Composition, biomass and structure of mangroves within the Zambezi River Delta

Treesearch

Carl C. Trettin; Christina E. Stringer; Stan Zarnoch

2015-01-01

We used a stratified random sampling design to inventory the mangrove vegetation within the Zambezi River Delta, Mozambique, to provide a basis for estimating biomass pools. We used canopy height, derived from remote sensing data, to stratify the inventory area, and then applied a spatial decision support system to objectively allocate sample plots among five...

Effects of unstratified and centre-stratified randomization in multi-centre clinical trials.

PubMed

Anisimov, Vladimir V

2011-01-01

This paper deals with the analysis of randomization effects in multi-centre clinical trials. The two randomization schemes most often used in clinical trials are considered: unstratified and centre-stratified block-permuted randomization. The prediction of the number of patients randomized to different treatment arms in different regions during the recruitment period accounting for the stochastic nature of the recruitment and effects of multiple centres is investigated. A new analytic approach using a Poisson-gamma patient recruitment model (patients arrive at different centres according to Poisson processes with rates sampled from a gamma distributed population) and its further extensions is proposed. Closed-form expressions for corresponding distributions of the predicted number of the patients randomized in different regions are derived. In the case of two treatments, the properties of the total imbalance in the number of patients on treatment arms caused by using centre-stratified randomization are investigated and for a large number of centres a normal approximation of imbalance is proved. The impact of imbalance on the power of the study is considered. It is shown that the loss of statistical power is practically negligible and can be compensated by a minor increase in sample size. The influence of patient dropout is also investigated. The impact of randomization on predicted drug supply overage is discussed. Copyright © 2010 John Wiley & Sons, Ltd.

Testing the Feasibility of Developmental Asset Measures on College Students to Guide Health Promotion Efforts

ERIC Educational Resources Information Center

Zullig, Keith J.; Ward, Rose Marie; King, Keith A.; Patton, Jon M.; Murray, Karen A.

2009-01-01

The purpose of this investigation was to assess the reliability and validity of eight developmental asset measures among a stratified, random sample (N = 540) of college students to guide health promotion efforts. The sample was randomly split to produce exploratory and confirmatory samples for factor analysis using principal axis factoring and…

Workforce Readiness: A Study of University Students' Fluency with Information Technology

ERIC Educational Resources Information Center

Kaminski, Karen; Switzer, Jamie; Gloeckner, Gene

2009-01-01

This study with data collected from a large sample of freshmen in 2001 and a random stratified sample of seniors in 2005 examined students perceived FITness (fluency with Information Technology). In the fall of 2001 freshmen at a medium sized research-one institution completed a survey and in spring 2005 a random sample of graduating seniors…

Computerized stratified random site-selection approaches for design of a ground-water-quality sampling network

USGS Publications Warehouse

Scott, J.C.

1990-01-01

Computer software was written to randomly select sites for a ground-water-quality sampling network. The software uses digital cartographic techniques and subroutines from a proprietary geographic information system. The report presents the approaches, computer software, and sample applications. It is often desirable to collect ground-water-quality samples from various areas in a study region that have different values of a spatial characteristic, such as land-use or hydrogeologic setting. A stratified network can be used for testing hypotheses about relations between spatial characteristics and water quality, or for calculating statistical descriptions of water-quality data that account for variations that correspond to the spatial characteristic. In the software described, a study region is subdivided into areal subsets that have a common spatial characteristic to stratify the population into several categories from which sampling sites are selected. Different numbers of sites may be selected from each category of areal subsets. A population of potential sampling sites may be defined by either specifying a fixed population of existing sites, or by preparing an equally spaced population of potential sites. In either case, each site is identified with a single category, depending on the value of the spatial characteristic of the areal subset in which the site is located. Sites are selected from one category at a time. One of two approaches may be used to select sites. Sites may be selected randomly, or the areal subsets in the category can be grouped into cells and sites selected randomly from each cell.

A comparison of two sampling designs for fish assemblage assessment in a large river

USGS Publications Warehouse

Kiraly, Ian A.; Coghlan, Stephen M.; Zydlewski, Joseph D.; Hayes, Daniel

2014-01-01

We compared the efficiency of stratified random and fixed-station sampling designs to characterize fish assemblages in anticipation of dam removal on the Penobscot River, the largest river in Maine. We used boat electrofishing methods in both sampling designs. Multiple 500-m transects were selected randomly and electrofished in each of nine strata within the stratified random sampling design. Within the fixed-station design, up to 11 transects (1,000 m) were electrofished, all of which had been sampled previously. In total, 88 km of shoreline were electrofished during summer and fall in 2010 and 2011, and 45,874 individuals of 34 fish species were captured. Species-accumulation and dissimilarity curve analyses indicated that all sampling effort, other than fall 2011 under the fixed-station design, provided repeatable estimates of total species richness and proportional abundances. Overall, our sampling designs were similar in precision and efficiency for sampling fish assemblages. The fixed-station design was negatively biased for estimating the abundance of species such as Common Shiner Luxilus cornutus and Fallfish Semotilus corporalis and was positively biased for estimating biomass for species such as White Sucker Catostomus commersonii and Atlantic Salmon Salmo salar. However, we found no significant differences between the designs for proportional catch and biomass per unit effort, except in fall 2011. The difference observed in fall 2011 was due to limitations on the number and location of fixed sites that could be sampled, rather than an inherent bias within the design. Given the results from sampling in the Penobscot River, application of the stratified random design is preferable to the fixed-station design due to less potential for bias caused by varying sampling effort, such as what occurred in the fall 2011 fixed-station sample or due to purposeful site selection.

Nonmanufacturing Businesses. U.S. Metric Study Interim Report.

ERIC Educational Resources Information Center

Cornog, June R.; Bunten, Elaine D.

In this fifth interim report on the feasibility of a United States changeover to a metric system stems from the U.S. Metric Study, a primary stratified sample of 2,828 nonmanufacturing firms was randomly selected from 28,184 businesses taken from Social Security files, a secondary sample of 2,258 firms was randomly selected for replacement…

The Relationship between Teachers Commitment and Female Students Academic Achievements in Some Selected Secondary School in Wolaita Zone, Southern Ethiopia

ERIC Educational Resources Information Center

Bibiso, Abyot; Olango, Menna; Bibiso, Mesfin

2017-01-01

The purpose of this study was to investigate the relationship between teacher's commitment and female students academic achievement in selected secondary school of Wolaita zone, Southern Ethiopia. The research method employed was survey study and the sampling techniques were purposive, simple random and stratified random sampling. Questionnaire…

Sampling error in timber surveys

Treesearch

Austin Hasel

1938-01-01

Various sampling strategies are evaluated for efficiency in an interior ponderosa pine forest. In a 5760 acre tract, efficiency was gained by stratifying into quarter acre blocks and sampling randomly from within. A systematic cruise was found to be superior for volume estimation.

Hierarchical model analysis of the Atlantic Flyway Breeding Waterfowl Survey

USGS Publications Warehouse

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

2014-01-01

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

Teachers' Methodologies and Sources of Information on HIV/AIDS for Students with Visual Impairments in Selected Residential and Integrated Schools in Ghana

ERIC Educational Resources Information Center

Hayford, Samuel K.; Ocansey, Frederick

2017-01-01

This study reports part of a national survey on sources of information, education and communication materials on HIV/AIDS available to students with visual impairments in residential, segregated, and integrated schools in Ghana. A multi-staged stratified random sampling procedure and a purposive and simple random sampling approach, where…

Modeling of Academic Achievement of Primary School Students in Ethiopia Using Bayesian Multilevel Approach

ERIC Educational Resources Information Center

Sebro, Negusse Yohannes; Goshu, Ayele Taye

2017-01-01

This study aims to explore Bayesian multilevel modeling to investigate variations of average academic achievement of grade eight school students. A sample of 636 students is randomly selected from 26 private and government schools by a two-stage stratified sampling design. Bayesian method is used to estimate the fixed and random effects. Input and…

Assessment of the effect of population and diary sampling methods on estimation of school-age children exposure to fine particles.

PubMed

Che, W W; Frey, H Christopher; Lau, Alexis K H

2014-12-01

Population and diary sampling methods are employed in exposure models to sample simulated individuals and their daily activity on each simulation day. Different sampling methods may lead to variations in estimated human exposure. In this study, two population sampling methods (stratified-random and random-random) and three diary sampling methods (random resampling, diversity and autocorrelation, and Markov-chain cluster [MCC]) are evaluated. Their impacts on estimated children's exposure to ambient fine particulate matter (PM2.5 ) are quantified via case studies for children in Wake County, NC for July 2002. The estimated mean daily average exposure is 12.9 μg/m(3) for simulated children using the stratified population sampling method, and 12.2 μg/m(3) using the random sampling method. These minor differences are caused by the random sampling among ages within census tracts. Among the three diary sampling methods, there are differences in the estimated number of individuals with multiple days of exposures exceeding a benchmark of concern of 25 μg/m(3) due to differences in how multiday longitudinal diaries are estimated. The MCC method is relatively more conservative. In case studies evaluated here, the MCC method led to 10% higher estimation of the number of individuals with repeated exposures exceeding the benchmark. The comparisons help to identify and contrast the capabilities of each method and to offer insight regarding implications of method choice. Exposure simulation results are robust to the two population sampling methods evaluated, and are sensitive to the choice of method for simulating longitudinal diaries, particularly when analyzing results for specific microenvironments or for exposures exceeding a benchmark of concern. © 2014 Society for Risk Analysis.

Spatial Sampling of Weather Data for Regional Crop Yield Simulations

NASA Technical Reports Server (NTRS)

Van Bussel, Lenny G. J.; Ewert, Frank; Zhao, Gang; Hoffmann, Holger; Enders, Andreas; Wallach, Daniel; Asseng, Senthold; Baigorria, Guillermo A.; Basso, Bruno; Biernath, Christian;

CTEPP STANDARD OPERATING PROCEDURE FOR SAMPLE SELECTION (SOP-1.10)

EPA Science Inventory

The procedures for selecting CTEPP study subjects are described in the SOP. The primary, county-level stratification is by region and urbanicity. Six sample counties in each of the two states (North Carolina and Ohio) are selected using stratified random sampling and reflect ...

A nonparametric method to generate synthetic populations to adjust for complex sampling design features.

PubMed

Dong, Qi; Elliott, Michael R; Raghunathan, Trivellore E

2014-06-01

Outside of the survey sampling literature, samples are often assumed to be generated by a simple random sampling process that produces independent and identically distributed (IID) samples. Many statistical methods are developed largely in this IID world. Application of these methods to data from complex sample surveys without making allowance for the survey design features can lead to erroneous inferences. Hence, much time and effort have been devoted to develop the statistical methods to analyze complex survey data and account for the sample design. This issue is particularly important when generating synthetic populations using finite population Bayesian inference, as is often done in missing data or disclosure risk settings, or when combining data from multiple surveys. By extending previous work in finite population Bayesian bootstrap literature, we propose a method to generate synthetic populations from a posterior predictive distribution in a fashion inverts the complex sampling design features and generates simple random samples from a superpopulation point of view, making adjustment on the complex data so that they can be analyzed as simple random samples. We consider a simulation study with a stratified, clustered unequal-probability of selection sample design, and use the proposed nonparametric method to generate synthetic populations for the 2006 National Health Interview Survey (NHIS), and the Medical Expenditure Panel Survey (MEPS), which are stratified, clustered unequal-probability of selection sample designs.

A nonparametric method to generate synthetic populations to adjust for complex sampling design features

PubMed Central

Dong, Qi; Elliott, Michael R.; Raghunathan, Trivellore E.

2017-01-01

Outside of the survey sampling literature, samples are often assumed to be generated by a simple random sampling process that produces independent and identically distributed (IID) samples. Many statistical methods are developed largely in this IID world. Application of these methods to data from complex sample surveys without making allowance for the survey design features can lead to erroneous inferences. Hence, much time and effort have been devoted to develop the statistical methods to analyze complex survey data and account for the sample design. This issue is particularly important when generating synthetic populations using finite population Bayesian inference, as is often done in missing data or disclosure risk settings, or when combining data from multiple surveys. By extending previous work in finite population Bayesian bootstrap literature, we propose a method to generate synthetic populations from a posterior predictive distribution in a fashion inverts the complex sampling design features and generates simple random samples from a superpopulation point of view, making adjustment on the complex data so that they can be analyzed as simple random samples. We consider a simulation study with a stratified, clustered unequal-probability of selection sample design, and use the proposed nonparametric method to generate synthetic populations for the 2006 National Health Interview Survey (NHIS), and the Medical Expenditure Panel Survey (MEPS), which are stratified, clustered unequal-probability of selection sample designs. PMID:29200608

A stratified random survey of the proportion of poor quality oral artesunate sold at medicine outlets in the Lao PDR – implications for therapeutic failure and drug resistance

PubMed Central

Sengaloundeth, Sivong; Green, Michael D; Fernández, Facundo M; Manolin, Ot; Phommavong, Khamlieng; Insixiengmay, Vongsavanh; Hampton, Christina Y; Nyadong, Leonard; Mildenhall, Dallas C; Hostetler, Dana; Khounsaknalath, Lamphet; Vongsack, Latsamy; Phompida, Samlane; Vanisaveth, Viengxay; Syhakhang, Lamphone; Newton, Paul N

2009-01-01

Background Counterfeit oral artesunate has been a major public health problem in mainland SE Asia, impeding malaria control. A countrywide stratified random survey was performed to determine the availability and quality of oral artesunate in pharmacies and outlets (shops selling medicines) in the Lao PDR (Laos). Methods In 2003, 'mystery' shoppers were asked to buy artesunate tablets from 180 outlets in 12 of the 18 Lao provinces. Outlets were selected using stratified random sampling by investigators not involved in sampling. Samples were analysed for packaging characteristics, by the Fast Red Dye test, high-performance liquid chromatography (HPLC), mass spectrometry (MS), X-ray diffractometry and pollen analysis. Results Of 180 outlets sampled, 25 (13.9%) sold oral artesunate. Outlets selling artesunate were more commonly found in the more malarious southern Laos. Of the 25 outlets, 22 (88%; 95%CI 68–97%) sold counterfeit artesunate, as defined by packaging and chemistry. No artesunate was detected in the counterfeits by any of the chemical analysis techniques and analysis of the packaging demonstrated seven different counterfeit types. There was complete agreement between the Fast Red dye test, HPLC and MS analysis. A wide variety of wrong active ingredients were found by MS. Of great concern, 4/27 (14.8%) fakes contained detectable amounts of artemisinin (0.26–115.7 mg/tablet). Conclusion This random survey confirms results from previous convenience surveys that counterfeit artesunate is a severe public health problem. The presence of artemisinin in counterfeits may encourage malaria resistance to artemisinin derivatives. With increasing accessibility of artemisinin-derivative combination therapy (ACT) in Laos, the removal of artesunate monotherapy from pharmacies may be an effective intervention. PMID:19638225

A stratified random survey of the proportion of poor quality oral artesunate sold at medicine outlets in the Lao PDR - implications for therapeutic failure and drug resistance.

PubMed

Sengaloundeth, Sivong; Green, Michael D; Fernández, Facundo M; Manolin, Ot; Phommavong, Khamlieng; Insixiengmay, Vongsavanh; Hampton, Christina Y; Nyadong, Leonard; Mildenhall, Dallas C; Hostetler, Dana; Khounsaknalath, Lamphet; Vongsack, Latsamy; Phompida, Samlane; Vanisaveth, Viengxay; Syhakhang, Lamphone; Newton, Paul N

2009-07-28

Counterfeit oral artesunate has been a major public health problem in mainland SE Asia, impeding malaria control. A countrywide stratified random survey was performed to determine the availability and quality of oral artesunate in pharmacies and outlets (shops selling medicines) in the Lao PDR (Laos). In 2003, 'mystery' shoppers were asked to buy artesunate tablets from 180 outlets in 12 of the 18 Lao provinces. Outlets were selected using stratified random sampling by investigators not involved in sampling. Samples were analysed for packaging characteristics, by the Fast Red Dye test, high-performance liquid chromatography (HPLC), mass spectrometry (MS), X-ray diffractometry and pollen analysis. Of 180 outlets sampled, 25 (13.9%) sold oral artesunate. Outlets selling artesunate were more commonly found in the more malarious southern Laos. Of the 25 outlets, 22 (88%; 95%CI 68-97%) sold counterfeit artesunate, as defined by packaging and chemistry. No artesunate was detected in the counterfeits by any of the chemical analysis techniques and analysis of the packaging demonstrated seven different counterfeit types. There was complete agreement between the Fast Red dye test, HPLC and MS analysis. A wide variety of wrong active ingredients were found by MS. Of great concern, 4/27 (14.8%) fakes contained detectable amounts of artemisinin (0.26-115.7 mg/tablet). This random survey confirms results from previous convenience surveys that counterfeit artesunate is a severe public health problem. The presence of artemisinin in counterfeits may encourage malaria resistance to artemisinin derivatives. With increasing accessibility of artemisinin-derivative combination therapy (ACT) in Laos, the removal of artesunate monotherapy from pharmacies may be an effective intervention.

A Dexterous Optional Randomized Response Model

ERIC Educational Resources Information Center

Tarray, Tanveer A.; Singh, Housila P.; Yan, Zaizai

2017-01-01

This article addresses the problem of estimating the proportion Pi[subscript S] of the population belonging to a sensitive group using optional randomized response technique in stratified sampling based on Mangat model that has proportional and Neyman allocation and larger gain in efficiency. Numerically, it is found that the suggested model is…

A Facility Specialist Model for Improving Retention of Nursing Home Staff: Results from a Randomized, Controlled Study

ERIC Educational Resources Information Center

Pillemer, Karl; Meador, Rhoda; Henderson, Charles, Jr.; Robison, Julie; Hegeman, Carol; Graham, Edwin; Schultz, Leslie

2008-01-01

Purpose: This article reports on a randomized, controlled intervention study designed to reduce employee turnover by creating a retention specialist position in nursing homes. Design and Methods: We collected data three times over a 1-year period in 30 nursing homes, sampled in stratified random manner from facilities in New York State and…

Comparison of sampling strategies for object-based classification of urban vegetation from Very High Resolution satellite images

NASA Astrophysics Data System (ADS)

Rougier, Simon; Puissant, Anne; Stumpf, André; Lachiche, Nicolas

2016-09-01

Vegetation monitoring is becoming a major issue in the urban environment due to the services they procure and necessitates an accurate and up to date mapping. Very High Resolution satellite images enable a detailed mapping of the urban tree and herbaceous vegetation. Several supervised classifications with statistical learning techniques have provided good results for the detection of urban vegetation but necessitate a large amount of training data. In this context, this study proposes to investigate the performances of different sampling strategies in order to reduce the number of examples needed. Two windows based active learning algorithms from state-of-art are compared to a classical stratified random sampling and a third combining active learning and stratified strategies is proposed. The efficiency of these strategies is evaluated on two medium size French cities, Strasbourg and Rennes, associated to different datasets. Results demonstrate that classical stratified random sampling can in some cases be just as effective as active learning methods and that it should be used more frequently to evaluate new active learning methods. Moreover, the active learning strategies proposed in this work enables to reduce the computational runtime by selecting multiple windows at each iteration without increasing the number of windows needed.

Using known map category marginal frequencies to improve estimates of thematic map accuracy

NASA Technical Reports Server (NTRS)

Card, D. H.

1982-01-01

By means of two simple sampling plans suggested in the accuracy-assessment literature, it is shown how one can use knowledge of map-category relative sizes to improve estimates of various probabilities. The fact that maximum likelihood estimates of cell probabilities for the simple random sampling and map category-stratified sampling were identical has permitted a unified treatment of the contingency-table analysis. A rigorous analysis of the effect of sampling independently within map categories is made possible by results for the stratified case. It is noted that such matters as optimal sample size selection for the achievement of a desired level of precision in various estimators are irrelevant, since the estimators derived are valid irrespective of how sample sizes are chosen.

Evaluation of Students' Perceptions about Efficiency of Educational Club Practices in Primary Schools

ERIC Educational Resources Information Center

Gelen, Ismail; Onay, Ihsan; Varol, Volkan

2014-01-01

The purpose of this study is to examine the efficiency of "Educational Club Practices" that has been in Elementary School program since 2005-2006, by examining the attitudes of students about "Educational Club Practices". Sample was selected in two steps. First, stratified sampling was employed and then random sampling was…

A New Stratified Sampling Procedure which Decreases Error Estimation of Varroa Mite Number on Sticky Boards.

PubMed

Kretzschmar, A; Durand, E; Maisonnasse, A; Vallon, J; Le Conte, Y

2015-06-01

A new procedure of stratified sampling is proposed in order to establish an accurate estimation of Varroa destructor populations on sticky bottom boards of the hive. It is based on the spatial sampling theory that recommends using regular grid stratification in the case of spatially structured process. The distribution of varroa mites on sticky board being observed as spatially structured, we designed a sampling scheme based on a regular grid with circles centered on each grid element. This new procedure is then compared with a former method using partially random sampling. Relative error improvements are exposed on the basis of a large sample of simulated sticky boards (n=20,000) which provides a complete range of spatial structures, from a random structure to a highly frame driven structure. The improvement of varroa mite number estimation is then measured by the percentage of counts with an error greater than a given level. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A direct observation method for auditing large urban centers using stratified sampling, mobile GIS technology and virtual environments.

PubMed

Lafontaine, Sean J V; Sawada, M; Kristjansson, Elizabeth

2017-02-16

With the expansion and growth of research on neighbourhood characteristics, there is an increased need for direct observational field audits. Herein, we introduce a novel direct observational audit method and systematic social observation instrument (SSOI) for efficiently assessing neighbourhood aesthetics over large urban areas. Our audit method uses spatial random sampling stratified by residential zoning and incorporates both mobile geographic information systems technology and virtual environments. The reliability of our method was tested in two ways: first, in 15 Ottawa neighbourhoods, we compared results at audited locations over two subsequent years, and second; we audited every residential block (167 blocks) in one neighbourhood and compared the distribution of SSOI aesthetics index scores with results from the randomly audited locations. Finally, we present interrater reliability and consistency results on all observed items. The observed neighbourhood average aesthetics index score estimated from four or five stratified random audit locations is sufficient to characterize the average neighbourhood aesthetics. The SSOI was internally consistent and demonstrated good to excellent interrater reliability. At the neighbourhood level, aesthetics is positively related to SES and physical activity and negatively correlated with BMI. The proposed approach to direct neighbourhood auditing performs sufficiently and has the advantage of financial and temporal efficiency when auditing a large city.

An Efficient Alternative Mixed Randomized Response Procedure

ERIC Educational Resources Information Center

Singh, Housila P.; Tarray, Tanveer A.

2015-01-01

In this article, we have suggested a new modified mixed randomized response (RR) model and studied its properties. It is shown that the proposed mixed RR model is always more efficient than the Kim and Warde's mixed RR model. The proposed mixed RR model has also been extended to stratified sampling. Numerical illustrations and graphical…

The Role of Religiosity in Influencing Adolescent and Adult Alcohol Use in Trinidad

ERIC Educational Resources Information Center

Rollocks, Steve C. T.; Dass, Natasha; Seepersad, Randy; Mohammed, Linda

2008-01-01

This study examined the role of religiosity among adolescents' and adults' alcohol use in Trinidad. A stratified random sample design of 369 adolescents and 210 adult parents belonging to the various religious groups in Trinidad was employed. Participants were randomly selected from various educational districts across Trinidad. Adolescent…

Teachers' Attitude towards Implementation of Learner-Centered Methodology in Science Education in Kenya

ERIC Educational Resources Information Center

Ndirangu, Caroline

2017-01-01

This study aims to evaluate teachers' attitude towards implementation of learner-centered methodology in science education in Kenya. The study used a survey design methodology, adopting the purposive, stratified random and simple random sampling procedures and hypothesised that there was no significant relationship between the head teachers'…

Testing homogeneity of proportion ratios for stratified correlated bilateral data in two-arm randomized clinical trials.

PubMed

Pei, Yanbo; Tian, Guo-Liang; Tang, Man-Lai

2014-11-10

Stratified data analysis is an important research topic in many biomedical studies and clinical trials. In this article, we develop five test statistics for testing the homogeneity of proportion ratios for stratified correlated bilateral binary data based on an equal correlation model assumption. Bootstrap procedures based on these test statistics are also considered. To evaluate the performance of these statistics and procedures, we conduct Monte Carlo simulations to study their empirical sizes and powers under various scenarios. Our results suggest that the procedure based on score statistic performs well generally and is highly recommended. When the sample size is large, procedures based on the commonly used weighted least square estimate and logarithmic transformation with Mantel-Haenszel estimate are recommended as they do not involve any computation of maximum likelihood estimates requiring iterative algorithms. We also derive approximate sample size formulas based on the recommended test procedures. Finally, we apply the proposed methods to analyze a multi-center randomized clinical trial for scleroderma patients. Copyright © 2014 John Wiley & Sons, Ltd.

Physical Activity among Rural Older Adults with Diabetes

ERIC Educational Resources Information Center

Arcury, Thomas A.; Snively, Beverly M.; Bell, Ronny A.; Smith, Shannon L.; Stafford, Jeanette M.; Wetmore-Arkader, Lindsay K.; Quandt, Sara A.

2006-01-01

Purpose: This analysis describes physical activity levels and factors associated with physical activity in an ethnically diverse (African American, Native American, white) sample of rural older adults with diabetes. Method: Data were collected using a population-based, cross-sectional stratified random sample survey of 701 community-dwelling…

Remote Sensing, Sampling and Simulation Applications in Analyses of Insect Dispersion and Abundance in Cotton

Treesearch

J. L. Willers; J. M. McKinion; J. N. Jenkins

2006-01-01

Simulation was employed to create stratified simple random samples of different sample unit sizes to represent tarnished plant bug abundance at different densities within various habitats of simulated cotton fields. These samples were used to investigate dispersion patterns of this cotton insect. It was found that the assessment of spatial pattern varied as a function...

Improvement of Predictive Ability by Uniform Coverage of the Target Genetic Space

PubMed Central

Bustos-Korts, Daniela; Malosetti, Marcos; Chapman, Scott; Biddulph, Ben; van Eeuwijk, Fred

2016-01-01

Genome-enabled prediction provides breeders with the means to increase the number of genotypes that can be evaluated for selection. One of the major challenges in genome-enabled prediction is how to construct a training set of genotypes from a calibration set that represents the target population of genotypes, where the calibration set is composed of a training and validation set. A random sampling protocol of genotypes from the calibration set will lead to low quality coverage of the total genetic space by the training set when the calibration set contains population structure. As a consequence, predictive ability will be affected negatively, because some parts of the genotypic diversity in the target population will be under-represented in the training set, whereas other parts will be over-represented. Therefore, we propose a training set construction method that uniformly samples the genetic space spanned by the target population of genotypes, thereby increasing predictive ability. To evaluate our method, we constructed training sets alongside with the identification of corresponding genomic prediction models for four genotype panels that differed in the amount of population structure they contained (maize Flint, maize Dent, wheat, and rice). Training sets were constructed using uniform sampling, stratified-uniform sampling, stratified sampling and random sampling. We compared these methods with a method that maximizes the generalized coefficient of determination (CD). Several training set sizes were considered. We investigated four genomic prediction models: multi-locus QTL models, GBLUP models, combinations of QTL and GBLUPs, and Reproducing Kernel Hilbert Space (RKHS) models. For the maize and wheat panels, construction of the training set under uniform sampling led to a larger predictive ability than under stratified and random sampling. The results of our methods were similar to those of the CD method. For the rice panel, all training set construction methods led to similar predictive ability, a reflection of the very strong population structure in this panel. PMID:27672112

MID-ATLANTIC COASTAL STREAMS STUDY: STATISTICAL DESIGN FOR REGIONAL ASSESSMENT AND LANDSCAPE MODEL DEVELOPMENT

EPA Science Inventory

A network of stream-sampling sites was developed for the Mid-Atlantic Coastal Plain (New Jersey through North Carolina) a collaborative study between the U.S. Environmental Protection Agency and the U.S. Geological Survey. A stratified random sampling with unequal weighting was u...

Employee Engagement and Performance of Lecturers in Nigerian Tertiary Institutions

ERIC Educational Resources Information Center

Agbionu, Uchenna Clementina; Anyalor, Maureen; Nwali, Anthony Chukwuma

2018-01-01

The study investigated employee engagement and performance of lecturers in Nigerian Tertiary Institutions. It employed descriptive and correlation research designs. Stratified random sampling was used to select three tertiary institutions in Nigeria and the sample size of 314 lecturers was obtained through Taro Yamane. Questionnaires were…

MID-ATLANTIC COASTAL STREAMS STUDY: STATISTICAL DESIGN FOR REGIONAL ASSESSMENT AND LANDSCAPE MODEL DEVELOPMENT

EPA Science Inventory

A network of stream-sampling sites was developed for the Mid-Atlantic Coastal Plain (New Jersey through North Carolina) as part of collaborative research between the U.S. Environmental Protection Agency and the U.S. Geological Survey. A stratified random sampling with unequal wei...

Resource Utilisation and Curriculum Implementation in Community Colleges in Kenya

ERIC Educational Resources Information Center

Kigwilu, Peter Changilwa; Akala, Winston Jumba

2017-01-01

The study investigated how Catholic-sponsored community colleges in Nairobi utilise the existing physical facilities and teaching and learning resources for effective implementation of Artisan and Craft curricula. The study adopted a mixed methods research design. Proportional stratified random sampling was used to sample 172 students and 18…

Detection and monitoring of invasive exotic plants: a comparison of four sampling methods

Treesearch

Cynthia D. Huebner

2007-01-01

The ability to detect and monitor exotic invasive plants is likely to vary depending on the sampling method employed. Methods with strong qualitative thoroughness for species detection often lack the intensity necessary to monitor vegetation change. Four sampling methods (systematic plot, stratified-random plot, modified Whittaker, and timed meander) in hemlock and red...

Relationships among Teachers' Self-Efficacy and Students' Motivation, Atmosphere, and Satisfaction in Physical Education

ERIC Educational Resources Information Center

Pan, Yi-Hsiang

2014-01-01

The purpose of this study was to confirm the relationships among teachers' self-efficacy, and students' learning motivation, learning atmosphere, and learning satisfaction in senior high school physical education (PE). A sample of 462 PE teachers and 2681 students was drawn using stratified random sampling and cluster sampling from high schools in…

Public Participation Guide: Citizen Juries

EPA Pesticide Factsheets

Citizen juries involve creating a “jury” a representative sample of citizens (usually selected in a random or stratified manner) who are briefed in detail on the background and current thinking relating to a particular issue or project.

NEKTON-HABITAT ASSOCIATIONS IN A PACIFIC NORTHWEST (USA) ESTUARY

EPA Science Inventory

Nekton−habitat associations were determined in Yaquina Bay, Oregon, United States, using a stratified-by-habitat, random, estuary-wide sampling design. Three habitats (intertidal eelgrass [Zostera marina], mud shrimp [Upogebia pugettensis], and ghost shrimp [Neotrypaea californie...

Evaluation of different approaches for identifying optimal sites to predict mean hillslope soil moisture content

NASA Astrophysics Data System (ADS)

Liao, Kaihua; Zhou, Zhiwen; Lai, Xiaoming; Zhu, Qing; Feng, Huihui

2017-04-01

The identification of representative soil moisture sampling sites is important for the validation of remotely sensed mean soil moisture in a certain area and ground-based soil moisture measurements in catchment or hillslope hydrological studies. Numerous approaches have been developed to identify optimal sites for predicting mean soil moisture. Each method has certain advantages and disadvantages, but they have rarely been evaluated and compared. In our study, surface (0-20 cm) soil moisture data from January 2013 to March 2016 (a total of 43 sampling days) were collected at 77 sampling sites on a mixed land-use (tea and bamboo) hillslope in the hilly area of Taihu Lake Basin, China. A total of 10 methods (temporal stability (TS) analyses based on 2 indices, K-means clustering based on 6 kinds of inputs and 2 random sampling strategies) were evaluated for determining optimal sampling sites for mean soil moisture estimation. They were TS analyses based on the smallest index of temporal stability (ITS, a combination of the mean relative difference and standard deviation of relative difference (SDRD)) and based on the smallest SDRD, K-means clustering based on soil properties and terrain indices (EFs), repeated soil moisture measurements (Theta), EFs plus one-time soil moisture data (EFsTheta), and the principal components derived from EFs (EFs-PCA), Theta (Theta-PCA), and EFsTheta (EFsTheta-PCA), and global and stratified random sampling strategies. Results showed that the TS based on the smallest ITS was better (RMSE = 0.023 m3 m-3) than that based on the smallest SDRD (RMSE = 0.034 m3 m-3). The K-means clustering based on EFsTheta (-PCA) was better (RMSE <0.020 m3 m-3) than these based on EFs (-PCA) and Theta (-PCA). The sampling design stratified by the land use was more efficient than the global random method. Forty and 60 sampling sites are needed for stratified sampling and global sampling respectively to make their performances comparable to the best K-means method (EFsTheta-PCA). Overall, TS required only one site, but its accuracy was limited. The best K-means method required <8 sites and yielded high accuracy, but extra soil and terrain information is necessary when using this method. The stratified sampling strategy can only be used if no pre-knowledge about soil moisture variation is available. This information will help in selecting the optimal methods for estimation the area mean soil moisture.

Mathematics Skill of Fifteen Years Old Students in Yogyakarta in Solving Problems Like PISA

ERIC Educational Resources Information Center

Wulandari, Nidya Ferry; Jailani

2018-01-01

The aims of this research were to describe mathematics skill of 8th fifteen-year old students in Yogyakarta in solving problem of PISA. The sampling was combination of stratified and cluster random sampling. The sample consisting of 400 students was selected from fifteen schools. The data collection was by tests. The research finding revealed that…

An Analysis of Job Satisfaction Among Public, College or University, and Special Librarians.

ERIC Educational Resources Information Center

Miniter, John J.

Usable data relating to six elements of job satisfaction: work, supervision, people, pay, promotion, and total satisfaction, were collected from 190 of a total sample of 310 librarians, chosen by stratified random sampling techniques from library association membership lists. The librarians, both male and female, represented three types of…

Factors Influencing Mathematic Problem-Solving Ability of Sixth Grade Students

ERIC Educational Resources Information Center

Pimta, Sakorn; Tayraukham, Sombat; Nuangchalerm, Prasart

2009-01-01

Problem statement: This study aims to investigate factors influencing mathematic problem-solving ability of sixth grade students. One thousand and twenty eight of sixth grade students, studying in the second semester of academic year 2007 were sampled by stratified random sampling technique. Approach: The research instruments used in the study…

Community of Inquiry Method and Language Skills Acquisition: Empirical Evidence

ERIC Educational Resources Information Center

Preece, Abdul Shakhour Duncan

2015-01-01

The study investigates the effectiveness of community of inquiry method in preparing students to develop listening and speaking skills in a sample of junior secondary school students in Borno state, Nigeria. A sample of 100 students in standard classes was drawn in one secondary school in Maiduguri metropolis through stratified random sampling…

A Study of the Effects of an Altered Workweek.

ERIC Educational Resources Information Center

Wood Educational Consultants, Edmonton (Alberta).

The purpose of this study was to examine the effects of organizational change arising from alterations in the structuring of the workweek. Data were collected from a stratified random sample of management and nonmanagement personnel employed within the various branches of the Alberta Department of Education. The sample consisted of 132 standard…

Academic Optimism and Organizational Citizenship Behaviour amongst Secondary School Teachers

ERIC Educational Resources Information Center

Makvandi, Abdollah; Naderi, Farah; Makvandi, Behnam; Pasha, Reza; Ehteshamzadeh, Parvin

2018-01-01

The purpose of the study was to investigate the simple and multiple relationships between academic optimism and organizational-citizenship behavior amongst high school teachers in Ramhormoz, Iran. The sample consisted of 250 (125 female and 125 male) teachers, selected by stratified random sampling in 2016- 2017. The measurement tools included…

Perceptions of Preservice Teachers regarding the Integration of Information and Communication Technologies in Turkish Education Faculties

ERIC Educational Resources Information Center

Akbulut, Yavuz; Odabasi, H. Ferhan; Kuzu, Abdullah

2011-01-01

This study explored the views of pre-service teachers regarding the indicators of information and communication technologies (ICT) at Turkish education faculties. A cross-sectional survey design was implemented with graduating students enrolled in Turkish education faculties. A combination of stratified random sampling and systematic sampling was…

Supporting Students in Learning with Multiple Representation to Improve Student Mental Models on Atomic Structure Concepts

ERIC Educational Resources Information Center

Sunyono; Yuanita, L.; Ibrahim, M.

2015-01-01

The aim of this research is identify the effectiveness of a multiple representation-based learning model, which builds a mental model within the concept of atomic structure. The research sample of 108 students in 3 classes is obtained randomly from among students of Mathematics and Science Education Studies using a stratified random sampling…

The Malleability of Spatial Ability under Treatment of a FIRST LEGO League-Based Robotics Simulation

ERIC Educational Resources Information Center

Coxon, Steve V.

2012-01-01

A stratified random sample of volunteer participants (N = 75) aged 9 to 14 was drawn from 16 public school districts' gifted programs, including as many females (n = 28) and children from groups traditionally underrepresented in gifted programs (n = 18) as available. Participants were randomly divided into an experimental (n = 38) and a control…

Methodology Series Module 5: Sampling Strategies.

PubMed

Setia, Maninder Singh

2016-01-01

Once the research question and the research design have been finalised, it is important to select the appropriate sample for the study. The method by which the researcher selects the sample is the ' Sampling Method'. There are essentially two types of sampling methods: 1) probability sampling - based on chance events (such as random numbers, flipping a coin etc.); and 2) non-probability sampling - based on researcher's choice, population that accessible & available. Some of the non-probability sampling methods are: purposive sampling, convenience sampling, or quota sampling. Random sampling method (such as simple random sample or stratified random sample) is a form of probability sampling. It is important to understand the different sampling methods used in clinical studies and mention this method clearly in the manuscript. The researcher should not misrepresent the sampling method in the manuscript (such as using the term ' random sample' when the researcher has used convenience sample). The sampling method will depend on the research question. For instance, the researcher may want to understand an issue in greater detail for one particular population rather than worry about the ' generalizability' of these results. In such a scenario, the researcher may want to use ' purposive sampling' for the study.

Methodology Series Module 5: Sampling Strategies

PubMed Central

Setia, Maninder Singh

2016-01-01

Once the research question and the research design have been finalised, it is important to select the appropriate sample for the study. The method by which the researcher selects the sample is the ‘ Sampling Method’. There are essentially two types of sampling methods: 1) probability sampling – based on chance events (such as random numbers, flipping a coin etc.); and 2) non-probability sampling – based on researcher's choice, population that accessible & available. Some of the non-probability sampling methods are: purposive sampling, convenience sampling, or quota sampling. Random sampling method (such as simple random sample or stratified random sample) is a form of probability sampling. It is important to understand the different sampling methods used in clinical studies and mention this method clearly in the manuscript. The researcher should not misrepresent the sampling method in the manuscript (such as using the term ‘ random sample’ when the researcher has used convenience sample). The sampling method will depend on the research question. For instance, the researcher may want to understand an issue in greater detail for one particular population rather than worry about the ‘ generalizability’ of these results. In such a scenario, the researcher may want to use ‘ purposive sampling’ for the study. PMID:27688438

Emotional, Social, Educational Adjustment of Higher Secondary School Students in Relation to Academic Achievement

ERIC Educational Resources Information Center

Sekar, J. Master Arul; Lawrence, A.S. Arul

2016-01-01

The present study aims to investigate whether there is any significant relationship between adjustment and academic achievement of higher secondary school students. In this survey study, the investigators used stratified random sampling technique for selecting the sample from the population. The stratification was done on the basis of gender and…

Assessing accuracy of point fire intervals across landscapes with simulation modelling

Treesearch

Russell A. Parsons; Emily K. Heyerdahl; Robert E. Keane; Brigitte Dorner; Joseph Fall

2007-01-01

We assessed accuracy in point fire intervals using a simulation model that sampled four spatially explicit simulated fire histories. These histories varied in fire frequency and size and were simulated on a flat landscape with two forest types (dry versus mesic). We used three sampling designs (random, systematic grids, and stratified). We assessed the sensitivity of...

Jackknifing Techniques for Evaluation of Equating Accuracy. Research Report. ETS RR-09-39

ERIC Educational Resources Information Center

Haberman, Shelby J.; Lee, Yi-Hsuan; Qian, Jiahe

2009-01-01

Grouped jackknifing may be used to evaluate the stability of equating procedures with respect to sampling error and with respect to changes in anchor selection. Properties of grouped jackknifing are reviewed for simple-random and stratified sampling, and its use is described for comparisons of anchor sets. Application is made to examples of item…

The Relationship between Happiness, Subjective Well-Being, Creativity and Job Performance of Primary School Teachers in Ramhormoz City

ERIC Educational Resources Information Center

Jalali, Zohreh; Heidari, Alireza

2016-01-01

The research aimed to investigate the relationship between happiness, subjective well-being, creativity and job performance of primary school teachers in Ramhormoz City. Hence, a sample of 330 individuals was selected through random stratified sampling. The research tools included Oxford Happiness Inventory, Subjective Well-being Scale by Keyes…

Inclusive Education in Spain: How Do Skills, Resources, and Supports Affect Regular Education Teachers' Perceptions of Inclusion?

ERIC Educational Resources Information Center

Chiner, Esther; Cardona, Maria Cristina

2013-01-01

This study examined regular education teachers' perceptions of inclusion in elementary and secondary schools in Spain and how these perceptions may differ depending on teaching experience, skills, and the availability of resources and supports. Stratified random sampling procedures were used to draw a representative sample of 336 general education…

Strategies for Coping with the Challenges of Incarceration among Nigerian Prison Inmates

ERIC Educational Resources Information Center

Agbakwuru, Chikwe; Awujo, Grace C.

2016-01-01

This paper investigated the strategies for coping with the challenges of incarceration among inmates of Port Harcourt Prison, Nigeria. The population was 2,997 inmates of the prison while the sample was 250 inmates drawn through stratified random sampling technique from the same Port Harcourt prison. Six research questions were posed and data for…

Employment Opportunities in Applied Biological and Agricultural Occupations in the Metropolitan Area of Chicago.

ERIC Educational Resources Information Center

Thomas, Hollie B.; Neavill, Arthur

Based on questionnaire data collected from a sample of employers, this phase of a larger research project ascertained employment opportunities in the area of applied biological and agricultural occupations in the metropolitan area of Chicago. Specific fields of business surveyed by stratified random sample were animal care, animal health care,…

Society Membership Survey: 1986 Salaries.

ERIC Educational Resources Information Center

Skelton, W. Keith; And Others

The fourth in a series of reports produced by the Education and Employment Statistics division of the American Insititute of Physics (AIP) is presented. Data are based on a stratified random sample survey of one-sixth of the U.S. and Canadian membership of the AIP member societies. In the spring of 1986, every individual in the sample received a…

Teaching Aptitude of Student Teachers and their Academic Achievements at Graduate Level

ERIC Educational Resources Information Center

Sajan, K. S.

2010-01-01

The present investigation aims at studying teaching aptitude of student teachers with respect to their gender and academic achievement at graduate level examination. The sample for this study is selected by stratified random sampling from the Teacher Education institutions of Malabar area of Kerala. Teaching Aptitude Test Battery (T A T B)…

Problems of Female School Teachers in District Kulgam (J&K)

ERIC Educational Resources Information Center

Rashid, Ruhee; Maharashi, Santosh Kumar

2015-01-01

The purpose of this study is to find the problems of employed female school teachers in district Kulgam. Sample of 100 employed women are selected from different education institutions as 20 Rehaber e Taleem (ReT) female teachers, 40 female teachers, 20 female masters and 20 female lecturers using stratified random sampling. In this study we use…

The Importance of Motivational Appeals to Cooperative Extension Agricultural Clientele. Summary of Research.

ERIC Educational Resources Information Center

Wilson, Gary; Newcomb, L. H.

A study was conducted to determine the relationship of certain motivational appeals to the extent of participation of extension clientele, as perceived by these clientele. A stratified random sample of thirty counties from the ten extension supervisory areas of Ohio was used for the study. This sample provided for 395 adult agricultural clientele…

The 1989 Georgia Survey of Adolescent Drug and Alcohol Use. Volume I: The Narrative Report for Survey Findings.

ERIC Educational Resources Information Center

Adams, Ronald D.; And Others

The 1989 Georgia Survey of Adolescent Drug and Alcohol Use was conducted in 373 schools throughout Georgia. The stratified random sample was obtained from schools that participated in the 1987 survey (in which 93% of the school systems in Georgia participated) and were selected randomly from strata based on size of community and geographic…

Stratified exact tests for the weak causal null hypothesis in randomized trials with a binary outcome.

PubMed

Chiba, Yasutaka

2017-09-01

Fisher's exact test is commonly used to compare two groups when the outcome is binary in randomized trials. In the context of causal inference, this test explores the sharp causal null hypothesis (i.e. the causal effect of treatment is the same for all subjects), but not the weak causal null hypothesis (i.e. the causal risks are the same in the two groups). Therefore, in general, rejection of the null hypothesis by Fisher's exact test does not mean that the causal risk difference is not zero. Recently, Chiba (Journal of Biometrics and Biostatistics 2015; 6: 244) developed a new exact test for the weak causal null hypothesis when the outcome is binary in randomized trials; the new test is not based on any large sample theory and does not require any assumption. In this paper, we extend the new test; we create a version of the test applicable to a stratified analysis. The stratified exact test that we propose is general in nature and can be used in several approaches toward the estimation of treatment effects after adjusting for stratification factors. The stratified Fisher's exact test of Jung (Biometrical Journal 2014; 56: 129-140) tests the sharp causal null hypothesis. This test applies a crude estimator of the treatment effect and can be regarded as a special case of our proposed exact test. Our proposed stratified exact test can be straightforwardly extended to analysis of noninferiority trials and to construct the associated confidence interval. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Training set optimization under population structure in genomic selection.

PubMed

Isidro, Julio; Jannink, Jean-Luc; Akdemir, Deniz; Poland, Jesse; Heslot, Nicolas; Sorrells, Mark E

2015-01-01

Population structure must be evaluated before optimization of the training set population. Maximizing the phenotypic variance captured by the training set is important for optimal performance. The optimization of the training set (TRS) in genomic selection has received much interest in both animal and plant breeding, because it is critical to the accuracy of the prediction models. In this study, five different TRS sampling algorithms, stratified sampling, mean of the coefficient of determination (CDmean), mean of predictor error variance (PEVmean), stratified CDmean (StratCDmean) and random sampling, were evaluated for prediction accuracy in the presence of different levels of population structure. In the presence of population structure, the most phenotypic variation captured by a sampling method in the TRS is desirable. The wheat dataset showed mild population structure, and CDmean and stratified CDmean methods showed the highest accuracies for all the traits except for test weight and heading date. The rice dataset had strong population structure and the approach based on stratified sampling showed the highest accuracies for all traits. In general, CDmean minimized the relationship between genotypes in the TRS, maximizing the relationship between TRS and the test set. This makes it suitable as an optimization criterion for long-term selection. Our results indicated that the best selection criterion used to optimize the TRS seems to depend on the interaction of trait architecture and population structure.

Estimation of infection prevalence and sensitivity in a stratified two-stage sampling design employing highly specific diagnostic tests when there is no gold standard.

PubMed

Miller, Ezer; Huppert, Amit; Novikov, Ilya; Warburg, Alon; Hailu, Asrat; Abbasi, Ibrahim; Freedman, Laurence S

2015-11-10

In this work, we describe a two-stage sampling design to estimate the infection prevalence in a population. In the first stage, an imperfect diagnostic test was performed on a random sample of the population. In the second stage, a different imperfect test was performed in a stratified random sample of the first sample. To estimate infection prevalence, we assumed conditional independence between the diagnostic tests and develop method of moments estimators based on expectations of the proportions of people with positive and negative results on both tests that are functions of the tests' sensitivity, specificity, and the infection prevalence. A closed-form solution of the estimating equations was obtained assuming a specificity of 100% for both tests. We applied our method to estimate the infection prevalence of visceral leishmaniasis according to two quantitative polymerase chain reaction tests performed on blood samples taken from 4756 patients in northern Ethiopia. The sensitivities of the tests were also estimated, as well as the standard errors of all estimates, using a parametric bootstrap. We also examined the impact of departures from our assumptions of 100% specificity and conditional independence on the estimated prevalence. Copyright © 2015 John Wiley & Sons, Ltd.

The Relationship between School Achievement and Peer Harassment in Canadian Adolescents: The Importance of Mediating Factors

ERIC Educational Resources Information Center

Beran, Tanya N.; Lupart, Judy

2009-01-01

The relationship between school achievement and peer harassment was examined using individual and peer characteristics as mediating factors. The sample consisted of adolescents age 12-15 years (n = 4,111) drawn from the Canadian National Longitudinal Survey of Children and Youth, which is a stratified random sample of 22,831 households in Canada.…

The Effective Management of Primary Schools in Ekiti State, Nigeria: An Analytical Assessment

ERIC Educational Resources Information Center

Adeyemi, T. O.

2009-01-01

This study investigated the management of education in primary schools in Ekiti State, Nigeria. As a correlational research, the study population comprised all the 694 primary schools in the State. Out of this, a sample of 320 schools was selected through the stratified random sampling technique. Two instruments were used to collect data for the…

A Validation Study of the Revised Personal Safety Decision Scale

ERIC Educational Resources Information Center

Kim, HaeJung; Hopkins, Karen M.

2017-01-01

Objective: The purpose of this study is to examine the reliability and validity of an 11-item Personal Safety Decision Scale (PSDS) in a sample of child welfare workers. Methods: Data were derived from a larger cross-sectional online survey to a random stratified sample of 477 public child welfare workers in a mid-Atlantic State. An exploratory…

North Carolina's Summer School Program for High-Risk Students: A Two-Year Follow-Up of Student Achievement.

ERIC Educational Resources Information Center

Ward, Martha Szegda

The long-term effectiveness of the North Carolina Basic Education Summer School Program (BEP) was examined. North Carolina has instituted a testing and summer remediation program for academically at-risk students at grades 3, 6, and 8. The BEP sample was obtained by a stratified random sampling of schools in North Carolina. Results were…

Increasing the Precision of Estimates in Follow-Up Surveys: A Case Study. AIR 1983 Annual Forum Paper.

ERIC Educational Resources Information Center

Clark, Sheldon B.; Nichols, James O.

Survey data concerning teacher education program graduates were used to demonstrate the advantages of a stratified random sampling approach, with followup, relative to a one-shot mailing to an entire population. Sampling issues involved in such an approach are addressed, particularly with regard to quantifying the effects of nonresponse on the…

Survey Response in a Statewide Social Experiment: Differences in Being Located and Collaborating, by Race and Hispanic Origin

ERIC Educational Resources Information Center

Nam, Yunju; Mason, Lisa Reyes; Kim, Youngmi; Clancy, Margaret; Sherraden, Michael

2013-01-01

This study examined whether and how survey response differs by race and Hispanic origin, using data from birth certificates and survey administrative data for a large-scale statewide experiment. The sample consisted of mothers of infants selected from Oklahoma birth certificates using a stratified random sampling method (N = 7,111). This study…

High resolution satellite remote sensing used in a stratified random sampling scheme to quantify the constituent land cover components of the shifting cultivation mosaic of the Democratic Republic of Congo

NASA Astrophysics Data System (ADS)

Molinario, G.; Hansen, M.; Potapov, P.

2016-12-01

High resolution satellite imagery obtained from the National Geospatial Intelligence Agency through NASA was used to photo-interpret sample areas within the DRC. The area sampled is a stratifcation of the forest cover loss from circa 2014 that either occurred completely within the previosly mapped homogenous area of the Rural Complex, at it's interface with primary forest, or in isolated forest perforations. Previous research resulted in a map of these areas that contextualizes forest loss depending on where it occurs and with what spatial density, leading to a better understading of the real impacts on forest degradation of livelihood shifting cultivation. The stratified random sampling approach of these areas allows the characterization of the constituent land cover types within these areas, and their variability throughout the DRC. Shifting cultivation has a variable forest degradation footprint in the DRC depending on many factors that drive it, but it's role in forest degradation and deforestation had been disputed, leading us to investigate and quantify the clearing and reuse rates within the strata throughout the country.

Education Needs of Michigan Farmers

ERIC Educational Resources Information Center

Suvedi, Murari; Jeong, Eunseong; Coombs, John

2010-01-01

In 2008 MSU Extension evaluated their program to identify the major areas of educational need for Michigan farmers and agribusiness operators. Surveys were mailed to a stratified random sample from Michigan Agricultural Statistics Service records of dairy, livestock, swine, cash crops, fruit, vegetable, and nursery/greenhouse producers. Findings…

New Mathematical Strategy Using Branch and Bound Method

NASA Astrophysics Data System (ADS)

Tarray, Tanveer Ahmad; Bhat, Muzafar Rasool

In this paper, the problem of optimal allocation in stratified random sampling is used in the presence of nonresponse. The problem is formulated as a nonlinear programming problem (NLPP) and is solved using Branch and Bound method. Also the results are formulated through LINGO.

[Study of spatial stratified sampling strategy of Oncomelania hupensis snail survey based on plant abundance].

PubMed

Xun-Ping, W; An, Z

2017-07-27

Objective To optimize and simplify the survey method of Oncomelania hupensis snails in marshland endemic regions of schistosomiasis, so as to improve the precision, efficiency and economy of the snail survey. Methods A snail sampling strategy (Spatial Sampling Scenario of Oncomelania based on Plant Abundance, SOPA) which took the plant abundance as auxiliary variable was explored and an experimental study in a 50 m×50 m plot in a marshland in the Poyang Lake region was performed. Firstly, the push broom surveyed data was stratified into 5 layers by the plant abundance data; then, the required numbers of optimal sampling points of each layer through Hammond McCullagh equation were calculated; thirdly, every sample point in the line with the Multiple Directional Interpolation (MDI) placement scheme was pinpointed; and finally, the comparison study among the outcomes of the spatial random sampling strategy, the traditional systematic sampling method, the spatial stratified sampling method, Sandwich spatial sampling and inference and SOPA was performed. Results The method (SOPA) proposed in this study had the minimal absolute error of 0.213 8; and the traditional systematic sampling method had the largest estimate, and the absolute error was 0.924 4. Conclusion The snail sampling strategy (SOPA) proposed in this study obtains the higher estimation accuracy than the other four methods.

Iodine and mental development of children 5 years old and under: a systematic review and meta-analysis.

PubMed

Bougma, Karim; Aboud, Frances E; Harding, Kimberly B; Marquis, Grace S

2013-04-22

Several reviews and meta-analyses have examined the effects of iodine on mental development. None focused on young children, so they were incomplete in summarizing the effects on this important age group. The current systematic review therefore examined the relationship between iodine and mental development of children 5 years old and under. A systematic review of articles using Medline (1980-November 2011) was carried out. We organized studies according to four designs: (1) randomized controlled trial with iodine supplementation of mothers; (2) non-randomized trial with iodine supplementation of mothers and/or infants; (3) prospective cohort study stratified by pregnant women's iodine status; (4) prospective cohort study stratified by newborn iodine status. Average effect sizes for these four designs were 0.68 (2 RCT studies), 0.46 (8 non-RCT studies), 0.52 (9 cohort stratified by mothers' iodine status), and 0.54 (4 cohort stratified by infants' iodine status). This translates into 6.9 to 10.2 IQ points lower in iodine deficient children compared with iodine replete children. Thus, regardless of study design, iodine deficiency had a substantial impact on mental development. Methodological concerns included weak study designs, the omission of important confounders, small sample sizes, the lack of cluster analyses, and the lack of separate analyses of verbal and non-verbal subtests. Quantifying more precisely the contribution of iodine deficiency to delayed mental development in young children requires more well-designed randomized controlled trials, including ones on the role of iodized salt.

A System Approach to Navy Medical Education and Training. Appendix 18. Radiation Technician.

DTIC Science & Technology

1974-08-31

attrition was forecast to approximate twenty percent, final sample and sub-sample sizes were adjusted accordingly. Stratified random sampling... HYPERTENSIVE INTRAVENOUS PYELOGRAMS 2 ITAKE RENAL LOOPOGRAMI I 3 ITAKE CIXU, I.Eo CONSTANT INFUSION 4 10 RENAL SPLIT FUNCTION TEST, E.G. STAMEY 5...ITAKE PORTAL FILM OF AREA BEING TREATED WITH COBALT 32 [INFORM DOCTOR OF UNEXPECTED X-RAY FINDINGS 33 IREAD X-RAY FILMS FOR TECHNICAL ADEQUACY 34

Computers in Public Education Study.

ERIC Educational Resources Information Center

HBJ Enterprises, Highland Park, NJ.

This survey conducted for the National Institute of Education reports the use of computers in U.S. public schools in the areas of instructional computing, student accounting, management of educational resources, research, guidance, testing, and library applications. From a stratified random sample of 1800 schools in varying geographic areas and…

Factors Affecting Retirement Attitude among Elementary School Teachers

ERIC Educational Resources Information Center

Hsu, Wan-Chen; Chiang, Chia-Hsun; Chuang, Hsueh-Hua

2015-01-01

This study investigated the relationships of teacher efficacy, perceived organizational control, and the teacher-student age gap with teachers' retirement attitudes. Stratified random sampling was adopted to collect survey responses. A total of 498 valid surveys from 33 elementary schools were collected. Correlational analyses revealed significant…

Multi-Sensory Intervention Observational Research

ERIC Educational Resources Information Center

Thompson, Carla J.

2011-01-01

An observational research study based on sensory integration theory was conducted to examine the observed impact of student selected multi-sensory experiences within a multi-sensory intervention center relative to the sustained focus levels of students with special needs. A stratified random sample of 50 students with severe developmental…

Mother Knows Best? Inhibitory Maternal Gatekeeping, Psychological Control, and the Mother-Adolescent Relationship

ERIC Educational Resources Information Center

Holmes, Erin Kramer; Dunn, KayLee C.; Harper, James; Dyer, W. Justin; Day, Randal D.

2013-01-01

We used structural equation modeling to explore associations between inhibitory maternal gatekeeping attitudes, reports of inhibitory maternal gatekeeping behaviors, maternal psychological control, observed mother-adolescent warmth, and adolescent reports of maternal involvement. Our random stratified sample consisted of 315 mothers and their…

Development of a sampling strategy and sample size calculation to estimate the distribution of mammographic breast density in Korean women.

PubMed

Jun, Jae Kwan; Kim, Mi Jin; Choi, Kui Son; Suh, Mina; Jung, Kyu-Won

2012-01-01

Mammographic breast density is a known risk factor for breast cancer. To conduct a survey to estimate the distribution of mammographic breast density in Korean women, appropriate sampling strategies for representative and efficient sampling design were evaluated through simulation. Using the target population from the National Cancer Screening Programme (NCSP) for breast cancer in 2009, we verified the distribution estimate by repeating the simulation 1,000 times using stratified random sampling to investigate the distribution of breast density of 1,340,362 women. According to the simulation results, using a sampling design stratifying the nation into three groups (metropolitan, urban, and rural), with a total sample size of 4,000, we estimated the distribution of breast density in Korean women at a level of 0.01% tolerance. Based on the results of our study, a nationwide survey for estimating the distribution of mammographic breast density among Korean women can be conducted efficiently.

Scientific Reasoning and Its Relationship with Problem Solving: The Case of Upper Primary Science Teachers

ERIC Educational Resources Information Center

Alshamali, Mahmoud A.; Daher, Wajeeh M.

2016-01-01

This study aimed at identifying the levels of scientific reasoning of upper primary stage (grades 4-7) science teachers based on their use of a problem-solving strategy. The study sample (N = 138; 32 % male and 68 % female) was randomly selected using stratified sampling from an original population of 437 upper primary school teachers. The…

Sexual Sensation Seeking, Social Stress, and Coping Styles as Predictors of HIV/STD Risk Behaviors in Adolescents

ERIC Educational Resources Information Center

Teva, Inmaculada; Bermudez, Maria Paz; Buela-Casal, Gualberto

2010-01-01

The aim of this study was to assess whether coping styles, social stress, and sexual sensation seeking were predictors of HIV/STD risk behaviours in adolescents. A representative sample of 4,456 female and male Spanish high school students aged 13 to 18 years participated. A stratified random sampling procedure was used. Self-report questionnaires…

The Relationship of Family Satisfaction to Satisfaction with the Military Way of Life among Soldiers. Technical Report 864.

ERIC Educational Resources Information Center

Bowen, Gary L.

This study investigated the relationship between soldiers' satisfaction with the environment for families in the Army and satisfaction with the military way of life. The report is based on a secondary analysis of the responses of a stratified random sample of 9,198 Army personnel, a sample that participated in the 1985 Department of Defense…

The linear trend of headache prevalence and some headache features in school children.

PubMed

Ozge, Aynur; Buğdayci, Resul; Saşmaz, Tayyar; Kaleağasi, Hakan; Kurt, Oner; Karakelle, Ali; Siva, Aksel

2007-04-01

The objectives of this study were to determine the age and sex dependent linear trend of recurrent headache prevalence in schoolchildren in Mersin. A stratified sample composed of 5562 children; detailed characteristics were previously published. In this study the prevalence distribution of headache by age and sex showed a peak in the female population at the age of 11 (27.2%) with a plateau in the following years. The great stratified random sample results suggested that, in addition to socio-demographic features, detailed linear trend analysis showed headache features of children with headache have some specific characteristics dependent on age, gender and headache type. This study results can constitute a basis for the future epidemiological based studies.

Kindergarten Teachers' Experience with Reporting Child Abuse in Taiwan

ERIC Educational Resources Information Center

Feng, Jui-Ying; Huang, Tzu-Yi; Wang, Chi-Jen

2010-01-01

Objective: The objectives were to examine factors associated with reporting child abuse among kindergarten teachers in Taiwan based on the Theory of Planned Behavior (TPB). Method: A stratified quota sampling technique was used to randomly select kindergarten teachers in Taiwan. The Child Abuse Intention Report Scale, which includes demographics,…

Psychological Distress and Related Factors in Female College Students

ERIC Educational Resources Information Center

Vazquez, Fernando L.; Otero, Patricia; Diaz, Olga

2012-01-01

Objective: This study assessed the psychological distress in Spanish college women and analyzed it in relation to sociodemographic and academic factors. Participants and Methods: The authors selected a stratified random sampling of 1,043 college women (average age of 22.2 years). Sociodemographic and academic information were collected, and…

Physical Activity among Older People Living Alone in Shanghai, China

ERIC Educational Resources Information Center

Chen, Yu; While, Alison E; Hicks, Allan

2015-01-01

Objective: To investigate physical activity among older people living alone in Shanghai, People's Republic of China, and key factors contributing to their physical activity. Methods: A cross-sectional questionnaire survey was administered in nine communities in Shanghai, using a stratified random cluster sample: 521 community-dwelling older people…

Determinants of Teachers' Attitudes towards E- Learning in Tanzanian Higher Learning Institutions

ERIC Educational Resources Information Center

Kisanga, Dalton H.

2016-01-01

This survey research study presents the findings on determinants of teachers' attitudes towards e-learning in Tanzanian higher learning institutions. The study involved 258 teachers from 4 higher learning institutions obtained through stratified, simple random sampling. Questionnaires and documentary review were used in data collection. Data were…

Abundance and population characteristics of Northern Spotted Owls (Strix occidentalis caurina) in Olympic National Park, Washington

Treesearch

D. Erran Seaman

1997-01-01

We monitored the threatened Northern Spotted Owl (Strix occidentalis caurina) in Olympic National Park from 1992 through 1996. We used a stratified random sampling scheme to survey 35 plots totaling 236 km?, approximately 10 percent of the forested area of the park.

Empirically Exploring Higher Education Cultures of Assessment

ERIC Educational Resources Information Center

Fuller, Matthew B.; Skidmore, Susan T.; Bustamante, Rebecca M.; Holzweiss, Peggy C.

2016-01-01

Although touted as beneficial to student learning, cultures of assessment have not been examined adequately using validated instruments. Using data collected from a stratified, random sample (N = 370) of U.S. institutional research and assessment directors, the models tested in this study provide empirical support for the value of using the…

Drug and Alcohol Use by Canadian University Athletes: A National Survey.

ERIC Educational Resources Information Center

Spence, John C.; Gauvin, Lise

1996-01-01

Using a stratified random sampling procedure, 754 student athletes were surveyed regarding drug and alcohol use in eight different sports from eight universities across Canada. Provides statistics of substances athletes reported using, including pain medications, weight loss products, anabolic steroids, smokeless tobacco products, alcohol,…

Women in University Management: The Nigerian Experience

ERIC Educational Resources Information Center

Abiodun-Oyebanji, Olayemi; Olaleye, F.

2011-01-01

This study examined women in university management in Nigeria. It was a descriptive research of the survey type. The population of the study comprised all the public universities in southwest Nigeria, out of which three were selected through the stratified random sampling technique. Three hundred respondents who were in management positions were…

Causative factors and countermeasures for rural and suburban pedestrian accidents : accident data collection and analysis

DOT National Transportation Integrated Search

1977-03-01

The objectives of the study were to collect and analyze data on rural pedestrian accidents and to identify potential countermeasures. Data on a stratified random sample of over 1,500 rural and suburban accidents from six states was collected during i...

School Nurse Communication Effectiveness with Physicians and Satisfaction with School Health Services

ERIC Educational Resources Information Center

Volkman, Julie E.; Hillemeier, Marianne M.

2008-01-01

This study examined school nurses' communication with community physicians and its relationship to school nurse satisfaction with school health services. A stratified random sample of school nurses in Pennsylvania (N = 615) were surveyed about communication effectiveness with community physicians, satisfaction with school health services for…

Training Neighborhood Residents to Conduct a Survey

ERIC Educational Resources Information Center

Back, Susan Malone; Tseng, Wan-Chun; Li, Jiaqi; Wang, Yuanhua; Phan, Van Thanh; Yeter, Ibrahim Halil

2015-01-01

As a requirement for a federal neighborhood revitalization grant, the authors trained resident interviewers and coordinated the conduct of more than 1000 door-to-door interviews of a stratified random sample. The targeted area was a multiethnic, lower income neighborhood that continues to experience the effects of past segregation. Monitoring and…

APPLICATION OF A MULTIPURPOSE UNEQUAL-PROBABILITY STREAM SURVEY IN THE MID-ATLANTIC COASTAL PLAIN

EPA Science Inventory

A stratified random sample with unequal-probability selection was used to design a multipurpose survey of headwater streams in the Mid-Atlantic Coastal Plain. Objectives for data from the survey include unbiased estimates of regional stream conditions, and adequate coverage of un...

Change in Sense of Community: An Empirical Finding

ERIC Educational Resources Information Center

Loomis, Colleen; Dockett, Kathleen H.; Brodsky, Anne E.

2004-01-01

This study investigated changes in students' psychological sense of community (SOC) under two conditions of external threat against their urban, historically Black, public nonresidential university in a U.S. mid-Atlantic city. Two independent stratified random samples (N = 801 and N = 241) consisting of undergraduate and graduate women (61%) and…

EXTENT, PROPERTIES, AND LANDSCAPE SETTING OF GEOGRAPHICALLY ISOLATED WETLANDS IN URBAN SOUTHERN NEW ENGLAND WATERSHEDS

EPA Science Inventory

We assessed the extent and characteristics of geographically isolated wetlands (i.e., wetlands completely surrounded by upland) in a series of drainage basins in the urban northeast U.S. We employed a random sampling design that stratifies study sites according to their degree o...

Psychological Security-Insecurity of Illinois Central College Students.

ERIC Educational Resources Information Center

Grout, David R.

This study attempted to discover the distribution of feelings of security and insecurity in the population of Illinois Central College (ICC) and whether significant differences exist among various subgroups. A 10 per cent stratified random sample of students were administered Maslow's Security-Insecurity Inventory. No significant difference was…

Homophobia in Registered Nurses: Impact on LGB Youth

ERIC Educational Resources Information Center

Blackwell, Christopher W.; Kiehl, Ermalynn M.

2008-01-01

This study examined registered nurses' overall attitudes and homophobia towards gays and lesbians in the workplace. Homophobia scores, represented by the Attitudes Toward Lesbians and Gay Men (ATLG) Scale, was the dependent variable. Overall homophobia scores were assessed among a randomized stratified sample of registered nurses licensed in the…

The Analysis of Iranian Students' Persistence in Online Education

ERIC Educational Resources Information Center

Mahmodi, Mahdi; Ebrahimzade, Issa

2015-01-01

In the following research, the relationship between instructional interaction and student persistence in e-learning has been analyzed. In order to conduct a descriptive-analytic survey, 744 undergraduate e-students were selected by stratified random sampling method to examine not only the frequency and the methods of establishing an instructional…

Causative factors and countermeasures for rural and suburban pedestrian accidents : accident data collection and analysis--appendices

DOT National Transportation Integrated Search

1977-06-01

The objectives of the study were to collect and analyze data on rural pedestrian accidents and to identify potential countermeasures. Data on a stratified random sample of over 1,500 rural and suburban accidents from six states was collected during i...

Do Social Workers Make Better Child Welfare Workers than Non-Social Workers?

ERIC Educational Resources Information Center

Perry, Robin E.

2006-01-01

Objective: To empirically examine whether the educational background of child welfare workers in Florida impacts on performance evaluations of their work. Method: A proportionate, stratified random sample of supervisor and peer evaluations of child protective investigators and child protective service workers is conducted. ANOVA procedures are…

Perceptions of Professionalism among Individuals in the Child Care Field

ERIC Educational Resources Information Center

Martin, Sue; Meyer, James; Jones, Robin Caudle; Nelson, Laverne; Ting, Ling

2010-01-01

Individuals working with young children, birth through age five, continue to strive for professional recognition. Factors that contribute to a person's feelings about being a child care professional were investigated. Stratified random sampling was used for data collection. Participants in the study responded to mailed questionnaires concerning a…

Assessing Principals' Quality Assurance Strategies in Osun State Secondary Schools, Nigeria

ERIC Educational Resources Information Center

Fasasi, Yunus Adebunmi; Oyeniran, Saheed

2014-01-01

This paper examined principals' quality assurance strategies in secondary schools in Osun State, Nigeria. The study adopted a descriptive survey research design. Stratified random sampling technique was used to select 10 male and 10 female principals, and 190 male and190 female teachers. "Secondary School Principal Quality Assurance…

Factors Associated with the Fulfillment of Residential Preferences.

ERIC Educational Resources Information Center

Hwang, Sean-Shong; Albrecht, Don E.

A 1983 survey of Texas homebuyers reveals a high degree of mismatch between the preferred and actual residence of homebuyers. Such mismatch is examined using social/psychological, life-cycle, racial, socioeconomic, and occupational factors as possible explanations. Questionnaires mailed to a stratified random sample of 960 homebuyers across 12…

Interpersonal Features and Functions of Nonsuicidal Self-Injury

ERIC Educational Resources Information Center

Muehlenkamp, Jennifer; Brausch, Amy; Quigley, Katherine; Whitlock, Janis

2013-01-01

Etiological models of nonsuicidal self-injury (NSSI) suggest interpersonal features may be important to understand this behavior, but social functions and correlates have not been extensively studied. This study addresses existing limitations by examining interpersonal correlates and functions of NSSI within a stratified random sample of 1,243…

Factors Associated with Successful Functioning in American Indian Youths

ERIC Educational Resources Information Center

Silmere, Hile; Stiffman, Arlene Rubin

2006-01-01

This study examines environmental and cultural factors related to successful functioning in a stratified random sample of 401 American Indian youths. The success index included seven indicators: good mental health, being alcohol and drug free, absence of serious misbehavior, clean police record, good grades, positive psychosocial functioning, and…

Job Insecurity and Employee Well-Being.

ERIC Educational Resources Information Center

Vance, Robert J.; Kuhnert, Karl W.

This study explored the consequences of perceived job security and insecurity on the psychological and physical health of employees. Data were gathered from employees of a large midwestern manufacturing organization that produced products for material removal applications. Surveys were sent through company mail to a stratified random sample of 442…

DSM-5 field trials in the United States and Canada, Part I: study design, sampling strategy, implementation, and analytic approaches.

PubMed

Clarke, Diana E; Narrow, William E; Regier, Darrel A; Kuramoto, S Janet; Kupfer, David J; Kuhl, Emily A; Greiner, Lisa; Kraemer, Helena C

2013-01-01

This article discusses the design,sampling strategy, implementation,and data analytic processes of the DSM-5 Field Trials. The DSM-5 Field Trials were conducted by using a test-retest reliability design with a stratified sampling approach across six adult and four pediatric sites in the United States and one adult site in Canada. A stratified random sampling approach was used to enhance precision in the estimation of the reliability coefficients. A web-based research electronic data capture system was used for simultaneous data collection from patients and clinicians across sites and for centralized data management.Weighted descriptive analyses, intraclass kappa and intraclass correlation coefficients for stratified samples, and receiver operating curves were computed. The DSM-5 Field Trials capitalized on advances since DSM-III and DSM-IV in statistical measures of reliability (i.e., intraclass kappa for stratified samples) and other recently developed measures to determine confidence intervals around kappa estimates. Diagnostic interviews using DSM-5 criteria were conducted by 279 clinicians of varied disciplines who received training comparable to what would be available to any clinician after publication of DSM-5.Overall, 2,246 patients with various diagnoses and levels of comorbidity were enrolled,of which over 86% were seen for two diagnostic interviews. A range of reliability coefficients were observed for the categorical diagnoses and dimensional measures. Multisite field trials and training comparable to what would be available to any clinician after publication of DSM-5 provided “real-world” testing of DSM-5 proposed diagnoses.

Aggregating pixel-level basal area predictions derived from LiDAR data to industrial forest stands in North-Central Idaho

Treesearch

Andrew T. Hudak; Jeffrey S. Evans; Nicholas L. Crookston; Michael J. Falkowski; Brant K. Steigers; Rob Taylor; Halli Hemingway

2008-01-01

Stand exams are the principal means by which timber companies monitor and manage their forested lands. Airborne LiDAR surveys sample forest stands at much finer spatial resolution and broader spatial extent than is practical on the ground. In this paper, we developed models that leverage spatially intensive and extensive LiDAR data and a stratified random sample of...

The Effect Of Age At Harvest On Bending And Tensile Properties Of Loblolly Pine From The Coastal Plain

Treesearch

Robert H. McAlister; Alexander Clark; Joseph R. Saucier

1997-01-01

The effect of rotation age on strength and stiffness of lumber produced from unthinned loblolly pine stands in the Coastal Plain of Georgia was examined. Six stands representing 22-, 28-, and 40-year-old roations were sampled. A stratified random sample of trees 8 to 16 inches in diameter at breast height was selected from each stand and processed into lumber....

Sampling designs for HIV molecular epidemiology with application to Honduras.

PubMed

Shepherd, Bryan E; Rossini, Anthony J; Soto, Ramon Jeremias; De Rivera, Ivette Lorenzana; Mullins, James I

2005-11-01

Proper sampling is essential to characterize the molecular epidemiology of human immunodeficiency virus (HIV). HIV sampling frames are difficult to identify, so most studies use convenience samples. We discuss statistically valid and feasible sampling techniques that overcome some of the potential for bias due to convenience sampling and ensure better representation of the study population. We employ a sampling design called stratified cluster sampling. This first divides the population into geographical and/or social strata. Within each stratum, a population of clusters is chosen from groups, locations, or facilities where HIV-positive individuals might be found. Some clusters are randomly selected within strata and individuals are randomly selected within clusters. Variation and cost help determine the number of clusters and the number of individuals within clusters that are to be sampled. We illustrate the approach through a study designed to survey the heterogeneity of subtype B strains in Honduras.

Mechanisms of Learning Transfer in Adventure Education: Qualitative Results from the NOLS Transfer Survey

ERIC Educational Resources Information Center

Sibthorp, Jim; Furman, Nate; Paisley, Karen; Gookin, John; Schumann, Scott

2011-01-01

Transfer of learning from adventure programs remains of critical interest to adventure education professionals. Although some research has investigated what transfers, notably less has focused on mechanisms that might influence transfer. This paper explores the mechanisms of transfer reported by a stratified random sample of National Outdoor…

ASSESSMENT OF THE WRITTEN LANGUAGE OF DEAF STUDENTS.

ERIC Educational Resources Information Center

MARKS, CLAUDE H.; STUCKLESS, E. ROSS

THIS INVESTIGATION WAS CONDUCTED TO DESCRIBE THE WRITTEN LANGUAGE OF DEAF STUDENTS BETWEEN 10 AND 18 YEARS OF AGE IN TERMS OF SIX MEASURABLE VARIABLES, AND TO RELATE THESE VARIABLES TO TEACHER JUDGMENTS OF QUALITY OF LANGUAGE. TEN STRATIFIED RANDOM SAMPLES OF COMPOSITIONS BY DEAF STUDENTS WERE SELECTED FROM 14 RESIDENTIAL AND DAY EDUCATIONAL…

The Effects of Grouping Practices and Curricular Adjustments on Achievement

ERIC Educational Resources Information Center

Tieso, Carol

2005-01-01

The purpose of this study was to examine the effects of curricular (textbook, revised, and differentiated) and grouping (whole, between, and within-class) practices on intermediate students' achievement in mathematics. A pretest-posttest, quasi-experimental design using a stratified random sample of 31 teachers and their students (N = 645) was…

Collaborative Job Training in Rural Areas

ERIC Educational Resources Information Center

Green, Gary Paul; Galetto, Valeria; Haines, Anna

2003-01-01

We examine collaborative efforts by employers to provide job training in rural areas and assess how this collaboration affects the willingness of employers to train workers. Data are drawn from a telephone survey conducted in 2001 of a stratified random sample of 1,590 nonmetropolitan firms in the U.S. The literature on job training suggests that…

Private Sector Views of Vocational Education: A Statewide Employer Survey.

ERIC Educational Resources Information Center

Owens, Thomas R.; Monthey, Wanda

A study examined the views of private sector employers in Oregon on vocational education. During the study, researchers mailed questionnaires to a stratified random sample of 1,500 employers throughout Oregon. In addition, they surveyed another 140 employers who were identified as hiring the largest numbers of vocational education completers in…

Impact of Teachers' Beliefs on Mathematics Education

ERIC Educational Resources Information Center

Bayaga, Anass; Wadesango, Newman; Wadesango, Ongayi Vongai

2015-01-01

The objective of the current study was to analyse the impact of teachers' personal theory and beliefs (PTB) towards Mathematics teaching. A total of 183 respondents were involved in this study, using the stratified random sampling method with Cronbach's alpha of 0.87. Due to the objective of the research and the hypothesis, it was positioned…

Cultural Diversity of Los Angeles County Residents Using Undeveloped Natural Areas

Treesearch

Patrick T. Tierney; Rene F. Dahl; Chavez Deborah J.

1998-01-01

A model of ethnic participation at undeveloped natural areas was developed and tested. The proposed model included the constructs of socio-economic status, perceived discrimination, assimilation, and ethnicity. Undeveloped natural areas were defined as being located outside of cities and primarily natural in composition. A telephone survey of a stratified random sample...

Multimedia Usage among Islamic Education Lecturers at Higher Education Institution

ERIC Educational Resources Information Center

Hamzah, Mohd Isa; Rinaldi; Razak, Khadijah Abdul

2014-01-01

This study aims to examine the level of multimedia usage among Islamic education lecturers at higher education institutions in West Sumatera, Indonesia. The participants were chosen from three types of higher institutions by using stratified random sampling. The data was collected from 250 students using questionnaires. The findings showed that…

Training Objectives, Transfer, Validation and Evaluation: A Sri Lankan Study

ERIC Educational Resources Information Center

Wickramasinghe, Vathsala M.

2006-01-01

Using a stratified random sample, this paper examines the training practices of setting objectives, transfer, validation and evaluation in Sri Lanka. The paper further sets out to compare those practices across local, foreign and joint-venture companies based on the assumption that there may be significant differences across companies of different…

Job Demand in the Cosmetology Industry.

ERIC Educational Resources Information Center

Rudner, Lawrence M.; Deutermann, William V., Jr.

In order to determine job demand in the cosmetology industry, a survey was made of a nationally representative stratified random sample of 1,454 beauty salons, barber shops, and unisex salons in July 1991. Salon owners were asked about 1990 and their plans for the future. Survey results were supplemented with information about the industry…

Recruitment to Teaching: Career Expectations of South Carolina Young People.

ERIC Educational Resources Information Center

Lyson, Thomas A.

Using data collected from a stratified random sample of South Carolina high school seniors in 1969, the study compared the patterns of occupational choices among white and black boys and girls, and examined the relationship among race, sex, and teacher recruitment. Social class origin, local residence place, and scholastic performance were…

Workforce Improvement Network 2000 Survey of Virginia Employers.

ERIC Educational Resources Information Center

Foucar-Szocki, Diane; Bolt, Les

A stratified random sample of Virginia's 4,000 employers with over 100 employees was surveyed about workplace-based foundational basic skills (oral and written communication, reading, math, thinking skills, teamwork, English proficiency, and basic computer literacy). A total of 446 surveys were sent with a usable response rate of 18 percent.…

Evaluation of LEAA Funded Courts Training Programs. Volume I.

ERIC Educational Resources Information Center

McManis Associates, Inc., Washington, DC.

An impact evaluation of eight courts training project (CTP) institutes funded by the Law Enforcement Assistance Administration was conducted. After a literature search and visits to potential evaluation sites in all fifty states, twelve sites were selected from a random stratified sample of court systems. Data were obtained from 1047 respondents…

Social Strain, Self-Control, and Juvenile Gambling Pathology: Evidence From Chinese Adolescents

ERIC Educational Resources Information Center

Cheung, Nicole W. T.

2016-01-01

Despite recent concerns over youthful problem gambling, few gambling studies have looked into Asian adolescent populations. This study of a stratified, random sample of high school students in Hong Kong is designed to estimate the prevalence of gambling pathology among Chinese adolescents and to examine the relationships between social strain,…

An Employer Needs Assessment for Vocational Education.

ERIC Educational Resources Information Center

Muraski, Ed J.; Whiteman, Dick

An employer needs assessment study was performed at Porterville College (PC), in California in 1991 as part of a comprehensive educational planning process for PC and the surrounding area. A validated survey instrument was sent to a stratified random sampling of 593 employers in the community, asking them to provide general information about their…

Screening and Brief Intervention for Tobacco Use by Student Health Providers on College Campuses

ERIC Educational Resources Information Center

Sutfin, Erin L.; McNamara, Robert S.; Blocker, Jill N.; Ip, Edward H.; O'Brien, Mary Claire; Wolfson, Mark

2012-01-01

Objective: This study assessed college students' reports of tobacco screening and brief intervention by student health center providers. Participants: Participants were 3,800 students from 8 universities in North Carolina. Methods: Web-based survey of a stratified random sample of undergraduates. Results: Fifty-three percent reported ever visiting…

The King Pre-Retirement Checklist: Assessing Differences in Pre-Retirement Planning.

ERIC Educational Resources Information Center

Zitzow, Darryl; King, Donald N.

In an effort to assess the retirement preparedness of Midwestern populations above the age of 28, the King Pre-Retirement Checklist was administered to a sampling of 458 persons randomly selected and proportionally stratified by geographic location and community size. Factors examined were financial, social, family cohesion, mobility/health,…

Factors Influencing Federal Employee Worker Satisfaction: A Baseline Study.

ERIC Educational Resources Information Center

Schmidt, Wallace V.; And Others

Utilizing data from the Federal Employee Attitude Survey, 1979, a survey was distributed to a stratified random sample of 20,000 employees to identify and analyze the factors influencing federal employee worker satisfaction. Questions on the survey ranged from demographics to personal evaluations of the work environment as recorded on a…

School Instructional Climate and Student Achievement: An Examination of Group Norms for Differentiated Instruction

ERIC Educational Resources Information Center

Goddard, Yvonne; Goddard, Roger; Kim, Minjung

2015-01-01

The purpose of this article is to investigate the relationship between school instructional climate and students' fifth-grade mathematics and reading achievement, with a particular emphasis on norms for practice consistent with differentiated instruction. Using data from a stratified random sample of Michigan elementary schools, we employed…

Secondary School Science and Mathematics Teachers, Characteristics and Service Loads.

ERIC Educational Resources Information Center

Mills, Thomas J.

Determined were the educational and professional backgrounds, and some aspects of the operational environment of teachers of secondary school science and mathematics (Grades 7-12) in the public and private schools of the United States during the school year 1960-61. A stratified random sampling method was used to ensure proportional representation…

An Employer Needs Assessment for Vocational Education: Palomar Community College District.

ERIC Educational Resources Information Center

Muraski, Ed J.; Barker, Cherie

A study was conducted to determine the employment needs within the Palomar Community College District. Surveys were mailed to a stratified random sample of 600 North San Diego County employers, requesting respondents to provide information on type and size of business, to rank the occupational programs offered by Palomar according to employment…

Influences on Students Selecting Cooperative Education Programs in Michigan High Schools. Final Report.

ERIC Educational Resources Information Center

Woloszyk, Carl A.

Factors influencing the decision of high school students to enroll in cooperative education programs were investigated in a survey. The stratified random sample consisted of 275 high school students currently enrolled in cooperative education programs in five different types of communities throughout Michigan. The survey questionnaire included 8…

Maneuvering the Role as a Community College Artist-Educator: Scholarship Assessed

ERIC Educational Resources Information Center

Gibson, John R.; Murray, John P.

2009-01-01

This study examined how Texas community college artist-educators balance artistic productivity with their teaching responsibilities. The 98 survey respondents represented 76.6% of a stratified random sample of the full-time instructors in visual arts departments within the 50 Texas public community college districts. Access to studio space and…

Impact Evaluation of Further Mathematics Curriculum in Nigeria

ERIC Educational Resources Information Center

Odili, Godwin Alo; Asuru, Vincent A.

2011-01-01

This research was a perceptual survey study carried out to determine whether the goals of Further Mathematics Curriculum (FMC) are being achieved at the Senior Secondary School level. The sample for the study consisted of 240 FM final year students, 45 FM teachers and 180 undergraduates who were selected by a multistage stratified random sampling…

AIP Report, 1989 Salaries: Society Membership Survey.

ERIC Educational Resources Information Center

Kellman, Dawn; Scholz, Catherine

This report examines the variations in salaries by degree level, employment sector, geographic location, and work activity among members of the scientific labor force and educational system. The data are based on a stratified random sample of one-sixth of the U.S. membership of the American Institute of Physics Member Societies; approximately…

Public-Private Partnership and Infrastructural Development in Nigerian Universities

ERIC Educational Resources Information Center

Oduwaiye, R. O.; Sofoluwe, A. O.; Bello, T. O.; Durosaro, I. A.

2014-01-01

This study investigated the degree to which Public-Private Partnership (PPP) services are related to infrastructural development in Nigerian Universities. The research design used was descriptive survey method. The population for the study encompassed all the 20 universities in South-west Nigeria. Stratified random sampling was used to select 12…

Cigarette Smoking and Anti-Smoking Counseling Practices among Physicians in Wuhan, China

ERIC Educational Resources Information Center

Gong, Jie; Zhang, Zhifeng; Zhu, Zhaoyang; Wan, Jun; Yang, Niannian; Li, Fang; Sun, Huiling; Li, Weiping; Xia, Jiang; Zhou, Dunjin; Chen, Xinguang

2012-01-01

Purpose: The paper seeks to report data on cigarette smoking, anti-smoking practices, physicians' receipt of anti-smoking training, and the association between receipt of the training and anti-smoking practice among physicians in Wuhan, China. Design/methodology/approach: Participants were selected through the stratified random sampling method.…

Student Teaching in the United States. Executive Summary

ERIC Educational Resources Information Center

National Council on Teacher Quality, 2011

2011-01-01

In an effort to understand what makes a student teaching experience strong, the National Council on Teacher Quality (NCTQ) has undertaken this comprehensive review. Over a period of two years, NCTQ researchers examined the student teaching programs of a stratified random sample of 134 higher education institutions across the United States, with at…

Effects of spatial allocation and parameter variability on lakewide estimates from surveys of Lake Superior, North America’s largest lake

EPA Science Inventory

Lake Superior was sampled in 2011 using a Generalized Random Tessellation Stratified design (n=54 sites) to characterize biological and chemical properties of this huge aquatic resource, with statistical confidence. The lake was divided into two strata (inshore <100m and offsh...

An Investigation of the Difficulties Faced by EFL Undergraduates in Speaking Skills

ERIC Educational Resources Information Center

Al-Jamal, Dina A.; Al-Jamal, Ghadeer A.

2014-01-01

Since speaking well in English is crucial for English language literature undergraduates, the present study aimed at describing difficulties that may be encountered at an EFL setting. The sample was stratified random as drawn from six Jordanian public universities. Survey questionnaires as well as semi-structured interviews were constructed. 64…

Maternal Religiosity, Family Resources and Stressors, and Parent-Child Attachment Security in Northern Ireland

ERIC Educational Resources Information Center

Goeke-Morey, Marcie C.; Cairns, Ed; Merrilees, Christine E.; Schermerhorn, Alice C.; Shirlow, Peter; Cummings, E. Mark

2013-01-01

This study explores the associations between mothers' religiosity, and families' and children's functioning in a stratified random sample of 695 Catholic and Protestant mother-child dyads in socially deprived areas in Belfast, Northern Ireland, a region which has experienced centuries of sectarian conflict between Protestant Unionists and…

Sex Roles and Perceived Job Stress of Washington Elementary Principals.

ERIC Educational Resources Information Center

Torelli, Joseph A.

The relationship between elementary principals' perceived job stress and sex role is examined. Questionnaires mailed to a random stratified sample of 200 elementary principals in Washington state (50 females, 150 males) yielded 172 useable returns, an 86 percent response rate. Two measurement instruments were used: the Bem Sex Role Inventory…

Correlates of Home Health Care Services Use among the Elderly.

ERIC Educational Resources Information Center

Starrett, Richard A.; And Others

The use of health and social services is influenced by economic, community, geographic, organizational, societal, and environmental factors. A study was conducted to examine predisposing, enabling, and need-for-care factors related to the use of home health care services by a stratified random sample of 400 older adults. Predisposing factors…

Mitigating budget constraints on visitation volume surveys: the case of U.S. National forests

Treesearch

Ashley E. Askew; Donald B.K. English; Stanley J. Zarnoch; Neelam C. Poudyal; J.M. Bowker

2014-01-01

Stratified random sampling (SRS) provides a scientifically based estimate of a population comprising mutually exclusive, homogenous subgroups. In the National Visitor Use Monitoring (NVUM) program, SRS is used to estimate recreation visitation and visitor characteristics across activities on National forests. However, with rising costs and declining budgets, carrying...

Exploring the Impact of Applicants' Gender and Religion on Principals' Screening Decisions for Assistant Principal Applicants

ERIC Educational Resources Information Center

Bon, Susan C.

2009-01-01

In this experimental study, a national random sample of high school principals (stratified by gender) were asked to evaluate hypothetical applicants whose resumes varied by religion (Jewish, Catholic, nondenominational) and gender (male, female) for employment as assistant principals. Results reveal that male principals rate all applicants higher…

Exploring Student Understanding of Grades and Report Cards

ERIC Educational Resources Information Center

Gwidt, Kathleen M.

2010-01-01

This qualitative study was designed to identify how students from a single high school in the rural Midwest perceive grades and report cards. Stratified purposeful random sampling resulted in the inclusion of 14 students who provided journal entries and participated in one-on-one interviews for the purpose of exploring student understanding of…

Information Needs of State Directors of Vocational Education.

ERIC Educational Resources Information Center

McCracken, J. David

To identify the critical problems of state directors of vocational education and the information sources utilized by them, data were collected by mail questionnaire and a series of telephone interviews with a stratified random sample of 15 state directors. Analysis of the data with respect to major problems, methods used to seek information,…

Reference List Accuracy in Social Work Journals: A Follow-Up Analysis

ERIC Educational Resources Information Center

Mitchell-Williams, Missy T.; Skipper, Antonius D.; Alexander, Marvin C.; Wilks, Scott E.

2017-01-01

Purpose: Following up an "Research on Social Work Practice" article published a decade ago, this study aimed to examine reference error rates among five, widely circulated social work journals. Methods: A stratified random sample of references was selected from the year 2013 (N = 500, 100/journal). Each was verified against the original…

Primary Teacher Trainees Preparedness to Teach Science: A Gender Perspective

ERIC Educational Resources Information Center

Mutisya, Sammy M.

2015-01-01

The purpose of this study was to determine Primary Teacher Education (PTE) Trainees' perceptions regarding their preparedness to teach science in primary schools. A descriptive survey research design was used and stratified proportionate random sampling techniques used to select 177 males and 172 females. The study found out that more male trainee…

Monitoring Achievement of Educational Governance/Management Policy Goals.

ERIC Educational Resources Information Center

Sederberg, Charles H.; Hendrix, Vernon L.

This paper reports on a field test of a system for monitoring the achievement of selected educational governance/management goals. The study entailed (1) collection of enrollment, revenue, expenditure, and teacher assignment data from a stratified random sample of Minnesota districts for a seven-year period, 1969-70 through 1975-76; (2) reduction…

Social Attitudes and Educational Needs of Women in the Chaffey Community College District.

ERIC Educational Resources Information Center

Lyman-Viera, Karen A.; Boggs, John

A socio-economically stratified sample of 368 randomly selected adult women residents of the Chaffey College district were interviewed to determine their demographic characteristics, educational needs and interests, perceived barriers to educational participation, and the adequacy of current college programs to meet the needs of women. Results of…

Early Adolescent Outcomes of Institutionally Deprived and Non-Deprived Adoptees. III. Quasi-Autism

ERIC Educational Resources Information Center

Rutter, Michael; Kreppner, Jana; Croft, Carla; Murin, Marianna; Colvert, Emma; Beckett, Celia; Castle, Jenny; Sonuga-Barke, Edmund

2007-01-01

Background: Some young children reared in profoundly depriving institutions have been found to show autistic-like patterns, but the developmental significance of these features is unknown. Methods: A randomly selected, age-stratified, sample of 144 children who had experienced an institutional upbringing in Romania and who were adopted by UK…

Assessment of the Implementation of Continuous Assessment: The Case of METTU University

ERIC Educational Resources Information Center

Walde, Getinet Seifu

2016-01-01

This paper examines the status of the implementation of continuous assessment (CA) in Mettu University. A random stratified sampling method was used to select 309 students and 29 instructors and purposive method used to select quality assurance and faculty Deans. Questionnaires, focus group discussion, interview and documents were used for data…

An Investigation on Secondary School Students' Attitude towards Science in Ogun State, Nigeria

ERIC Educational Resources Information Center

Sakariyau, A. O.; Taiwo, Michael O.; Ajagbe, Olalere W.

2016-01-01

The study investigated the attitudes of secondary school students towards science in Odeda Local Government Area of Ogun State, Nigeria. Two hundred senior secondary school students consisting of 84 males and 116 females were selected from five secondary schools using stratified random sampling techniques. A 20-item Attitude to Science…

Conflict Resolution Strategies in Non-Government Secondary Schools in Benue State, Nigeria

ERIC Educational Resources Information Center

Oboegbulem, Angie; Alfa, Idoko Alphonusu

2013-01-01

This study investigated perceived CRSs (conflict resolution strategies) for the resolution of conflicts in non-government secondary schools in Benue State, Nigeria. Three research questions and three hypotheses guided this study. Proportionate stratified random sampling technique was used in drawing 15% of the population which gave a total of 500…

Doing More with Less: A Preliminary Study of the School District Investment.

ERIC Educational Resources Information Center

MacPhail-Wilcox, Bettye

1983-01-01

Changes in cash management practices from 1978 to 1981 were investigated in a random sample of 145 North Carolina school districts, stratified by attendance size. Analysis using chi-square tests indicated the level of investment sophistication (as measured by the proportion of cash invested) has increased, especially for large districts. (RW)

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).

Improved Horvitz-Thompson Estimation of Model Parameters from Two-phase Stratified Samples: Applications in Epidemiology

PubMed Central

Breslow, Norman E.; Lumley, Thomas; Ballantyne, Christie M; Chambless, Lloyd E.; Kulich, Michal

2009-01-01

The case-cohort study involves two-phase sampling: simple random sampling from an infinite super-population at phase one and stratified random sampling from a finite cohort at phase two. Standard analyses of case-cohort data involve solution of inverse probability weighted (IPW) estimating equations, with weights determined by the known phase two sampling fractions. The variance of parameter estimates in (semi)parametric models, including the Cox model, is the sum of two terms: (i) the model based variance of the usual estimates that would be calculated if full data were available for the entire cohort; and (ii) the design based variance from IPW estimation of the unknown cohort total of the efficient influence function (IF) contributions. This second variance component may be reduced by adjusting the sampling weights, either by calibration to known cohort totals of auxiliary variables correlated with the IF contributions or by their estimation using these same auxiliary variables. Both adjustment methods are implemented in the R survey package. We derive the limit laws of coefficients estimated using adjusted weights. The asymptotic results suggest practical methods for construction of auxiliary variables that are evaluated by simulation of case-cohort samples from the National Wilms Tumor Study and by log-linear modeling of case-cohort data from the Atherosclerosis Risk in Communities Study. Although not semiparametric efficient, estimators based on adjusted weights may come close to achieving full efficiency within the class of augmented IPW estimators. PMID:20174455

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.

Data splitting for artificial neural networks using SOM-based stratified sampling.

PubMed

May, R J; Maier, H R; Dandy, G C

2010-03-01

Data splitting is an important consideration during artificial neural network (ANN) development where hold-out cross-validation is commonly employed to ensure generalization. Even for a moderate sample size, the sampling methodology used for data splitting can have a significant effect on the quality of the subsets used for training, testing and validating an ANN. Poor data splitting can result in inaccurate and highly variable model performance; however, the choice of sampling methodology is rarely given due consideration by ANN modellers. Increased confidence in the sampling is of paramount importance, since the hold-out sampling is generally performed only once during ANN development. This paper considers the variability in the quality of subsets that are obtained using different data splitting approaches. A novel approach to stratified sampling, based on Neyman sampling of the self-organizing map (SOM), is developed, with several guidelines identified for setting the SOM size and sample allocation in order to minimize the bias and variance in the datasets. Using an example ANN function approximation task, the SOM-based approach is evaluated in comparison to random sampling, DUPLEX, systematic stratified sampling, and trial-and-error sampling to minimize the statistical differences between data sets. Of these approaches, DUPLEX is found to provide benchmark performance with good model performance, with no variability. The results show that the SOM-based approach also reliably generates high-quality samples and can therefore be used with greater confidence than other approaches, especially in the case of non-uniform datasets, with the benefit of scalability to perform data splitting on large datasets. Copyright 2009 Elsevier Ltd. All rights reserved.

Dipolar eddies in a decaying stratified turbulent flow

NASA Astrophysics Data System (ADS)

Voropayev, S. I.; Fernando, H. J. S.; Morrison, R.

2008-02-01

Laboratory experiments on the evolution of dipolar (momentum) eddies in a stratified fluid in the presence of random background motions are described. A turbulent jet puff was used to generate the momentum eddies, and a decaying field of ambient random vortical motions was generated by a towed grid. Data on vorticity/velocity fields of momentum eddies, those of background motions, and their interactions were collected in the presence and absence of the other, and the main characteristics thereof were parametrized. Similarity arguments predict that dipolar eddies in stratified fluids may preserve their identity in decaying grid-generated stratified turbulence, which was verified experimentally. Possible applications of the results include mushroomlike currents and other naturally/artificially generated large dipolar eddies in strongly stratified layers of the ocean, the longevity of which is expected to be determined by the characteristics of the eddies and random background motions.

Alcohol- and Drug-Involved Driving in the United States: Methodology for the 2007 National Roadside Survey

PubMed Central

Lacey, John H.; Kelley-Baker, Tara; Voas, Robert B.; Romano, Eduardo; Furr-Holden, C. Debra; Torres, Pedro; Berning, Amy

2013-01-01

This article describes the methodology used in the 2007 U.S. National Roadside Survey to estimate the prevalence of alcohol- and drug-impaired driving and alcohol- and drug-involved driving. This study involved randomly stopping drivers at 300 locations across the 48 continental U.S. states at sites selected through a stratified random sampling procedure. Data were collected during a 2-hour Friday daytime session at 60 locations and during 2-hour nighttime weekend periods at 240 locations. Both self-report and biological measures were taken. Biological measures included breath alcohol measurements from 9,413 respondents, oral fluid samples from 7,719 respondents, and blood samples from 3,276 respondents. PMID:21997324

Demythologizing sex education in Oklahoma: an attitudinal study.

PubMed

Turner, N H

1983-08-01

A randomized study was conducted to determine the distribution of attitudes among Oklahomans of voting age toward sex education and to analyze the relationship of demographic, sociocultural, and attitudinal factors. The state was stratified into six regions. Forty-five percent of the sample lived in urban areas, and 55% in rural areas. Random digit dialing and random selection within households were utilized to ensure a representative sample of the population. Eighty percent of the sample was found to be favorable toward sex education in the public schools, while 20% was unfavorable. A majority of respondents in all religious groups including "fundamentalists" were favorable. Seventeen variables were found to be significant in the univariate analysis of the data; eight were not significant. In a multivariate analysis, three variables, age, Protestant denominational type and female employment, were shown to have predictive ability in determining favorability and unfavorability. Implications for building community support for sex education also are discussed.

In the Aftermath of Act 10: The Changed State of Teaching in a Changed State

ERIC Educational Resources Information Center

Swalwell, Katy; Schweber, Simone; Sinclair, Kristin; Gallagher, Jennifer; Schirmer, Eleni

2017-01-01

Act 10, the 2011 legislative ruling in Wisconsin that reduced public-sector unions' collective bargaining power, provides a descriptive case study to examine what happens to teachers when collective bargaining disappears. Analysis of interviews with social studies teachers (n = 26) from a stratified random sample of 13 districts shows that the…

Impact of Sex Education in Kogi State, Nigeria

ERIC Educational Resources Information Center

Sule, H. A.; Akor, J. A.; Toluhi, O. J.; Suleiman, R. O.; Akpihi, L.; Ali, O. U.

2015-01-01

The focus of this study was to investigate the impact of family sex education in secondary schools on students in Kogi State, Nigeria. The descriptive survey design was used for the study. A total of 1,960 secondary school students were drawn by stratified random sampling from 40 schools within Kogi State, Nigeria. Three research questions were…

Marital and Procreative Projections of Rural Louisiana Youth: A Historical Comparison.

ERIC Educational Resources Information Center

Smith, Kevin B.; Ohlendorf, George W.

Changes in marital and procreative projections among rural Louisiana high school youth between 1968 and 1972 were examined. In 1968 a proportionate, stratified, random cluster sampling technique was employed to secure data on seniors from 13 white and 7 black high schools. In 1972 public school integration and the establishment of private schools…

Teachers' Perception of Evaluation and Testing in Nigerian Secondary School System

ERIC Educational Resources Information Center

Oguzor, Nkasiobi Silas; Opara, Jacinta Agbarachi

2013-01-01

This study was aimed to find out from the teachers in Nigeria, their perception of the functionalism and their participation in the internal testing programme of secondary schools special reference to a state in southern Nigeria. A sample of 1,000 teachers was randomly stratified from the entire teachers' population of 6,000 in government-own…

Mental Health and Childhood Adversities: A Longitudinal Study in Kabul, Afghanistan

ERIC Educational Resources Information Center

Panter-Brick, Catherine; Goodman, Anna; Tol, Wietse; Eggerman, Mark

2011-01-01

Objective: To identify prospective predictors of mental health in Kabul, Afghanistan. Method: Using stratified random-sampling in schools, mental health and life events for 11- to 16-year-old students and their caregivers were assessed. In 2007, 1 year after baseline, the retention rate was 64% (n = 115 boys, 119 girls, 234 adults) with no…

Gender, Ethnicity, and Students' Perceptions about Science and Science-Related Careers in Fiji.

ERIC Educational Resources Information Center

Rennie, L. J.; Dunne, M.

1994-01-01

From data obtained from a questionnaire administered to a stratified, random sample of Form 5 (16-year-old) students in Fiji, it was concluded that gender and ethnicity were found to have no consistent relationship with students' perceptions, attitudes, and attributions about science. Different kinds of career advice were given to students on the…

Selected Health Practices Among Ohio's Rural Residents.

ERIC Educational Resources Information Center

Phillips, G. Howard; Pugh, Albert

Using a stratified random sample of 12 of Ohio's 88 counties, this 1967 study had as its objectives (1) to measure the level of participation in selected health practices by Ohio's rural residents, (2) to compare the level of participation in selected health practices of farm and rural nonfarm residents, and (3) to examine levels of participation…

Vocational + Academic Integration: Preparing Texas Students for the Work Force. Evaluation Report.

ERIC Educational Resources Information Center

Texas State Council on Vocational Education, Austin.

In a study of integration of vocational and academic education in Texas, administrators of a stratified random sample of 112 school districts in the state were surveyed, and 65% responded. Steps toward integration were being taken in 84% of the districts; however, only four districts have implemented integration plans described as comprehensive.…

Demographic trends in Claremont California’s street tree population

Treesearch

Natalie S. van Doorn; E. Gregory McPherson

2018-01-01

The aim of this study was to quantify street tree population dynamics in the city of Claremont, CA. A repeated measures survey (2000 and 2014) based on a stratified random sampling approach across size classes and for the most abundant 21 species was analyzed to calculate removal, growth, and replacement planting rates. Demographic rates were estimated using a...

Unmet Dental Needs and Barriers to Dental Care among Children with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Lai, Bien; Milano, Michael; Roberts, Michael W.; Hooper, Stephen R.

2012-01-01

Mail-in pilot-tested questionnaires were sent to a stratified random sample of 1,500 families from the North Carolina Autism Registry. Multivariate logistic regression analysis was used to determine the significance of unmet dental needs and other predictors. Of 568 surveys returned (Response Rate = 38%), 555 were complete and usable. Sixty-five…

A Correlation of Biology Teachers' Pupil Control Ideology and Their Classroom Teaching Practices.

ERIC Educational Resources Information Center

Jones, Paul L.; Blankenship, Jacob W.

The Pupil Control Ideology Form (PCI Form) and the Biology Classroom Activity Checklist (BCAC) were used to determine the relationship between teachers' stated pupil control ideology and the extent to which their students reported the use of inquiry methods in the classroom. Data were collected from a stratified random sample of 168 teachers and…

The Development and Validation of a Mechanical Critical Thinking Scale for High School Students

ERIC Educational Resources Information Center

Yu, Kuang-Chao; Lin, Kuen-Yi; Chang, Shu-Fen

2017-01-01

The purpose of this study was to develop a mechanical critical thinking scale for high school students. A stratified random sampling method was used to establish the norms. After pre-tests and item analysis, the scale was determined to have five subtest sections (i.e., recognition of assumptions, induction, deduction, interpretation, and…

Factors Affecting the Establishment of Young Farm Operators in Iowa and Implications for Agricultural Education.

ERIC Educational Resources Information Center

Crawford, Harold R.

A stratified random sample of 307 young farm operators from the five farming areas of Iowa were interviewed to: (1) ascertain factors influencing the establishment of young farm operators, (2) estimate the number of young farm operators becoming established each year, (3) determine their agricultural education needs, (4) examine differences among…

A Survey of Theatre in American Secondary Schools.

ERIC Educational Resources Information Center

Gillespie, Patti; And Others

In a survey of the status of theatre in high schools throughout the United States, questionnaires were sent to a random sample of high schools stratified by state and by school size. Analysis of the responses obtained from 606 schools (20.2% return) indicated that most secondary-school drama programs operate on the cocurricular level and emphasize…

Awareness, Knowledge and Exercise of Individual Employment Rights. Employment Relations Research Series.

ERIC Educational Resources Information Center

Meager, Nigel; Tyers, Claire; Perryman, Sarah; Rick, Jo; Willison, Rebecca

Recent employment law reforms in England precipitated a telephone survey of a stratified random sample of 5,120 employed people (1,000 respondents) that was intended to find their levels of awareness and knowledge of employment rights and their exercise of those rights. Survey results included the following: (1) nearly 70% of those questioned…

Multiple Intelligences Patterns of Students at King Saud University and Its Relationship with Mathematics' Achievement

ERIC Educational Resources Information Center

Kandeel, Refat A. A.

2016-01-01

The purpose of this study was to determine the multiple intelligences patterns of students at King Saud University and its relationship with academic achievement for the courses of Mathematics. The study sample consisted of 917 students were selected a stratified random manner, the descriptive analysis method and Pearson correlation were used, the…

The Interrelationships of Preadolescents' Student Characteristics Influencing Selection of Career Exploration Courses [And Abstract]. Industrial Arts Education Monograph No. 1.

ERIC Educational Resources Information Center

Meehan, Merrill L.

The study investigated the interaction of personal and environmental factors influencing seventh graders' selection of career exploration courses for increased exploration in the eighth grade. A stratified random sample (496 students) was drawn from the Pittsburgh Public School's Occupational, Vocational, and Technical Exploratory Program.…

A Classroom Observational Study of Qatar's Independent Schools: Instruction and School Reform

ERIC Educational Resources Information Center

Palmer, Douglas J.; Sadiq, Hissa M.; Lynch, Patricia; Parker, Dawn; Viruru, Radhika; Knight, Stephanie; Waxman, Hersh; Alford, Beverly; Brown, Danielle Bairrington; Rollins, Kayla; Stillisano, Jacqueline; Abu-Tineh, Abdullah M. Hamdan; Nasser, Ramzi; Allen, Nancy; Al-Binali, Hessa; Ellili, Maha; Al-Kateeb, Haithem; Al-Kubaisi, Huda

2016-01-01

Qatar initiated a K-12 national educational reform in 2001. However, there is limited information on the instructional practices of the teachers in the reform schools. This project was an observational study of classrooms with a stratified random sample of the first six cohorts of reform schools. Specifically, 156 classrooms were observed in 29…

The Malleability of Spatial Ability under Treatment of a FIRST LEGO League-Based Robotics Unit

ERIC Educational Resources Information Center

Coxon, Steven Vincent

2012-01-01

Spatial ability is important to science, technology, engineering, and math (STEM) success, but spatial talents are rarely developed in schools. Likewise, the gifted may become STEM innovators, but they are rarely provided with pedagogy appropriate to develop their abilities in schools. A stratified random sample of volunteer participants (n = 75)…

Date Fighting Experiences among College Students: Are They Associated with Other Health-Risk Behaviors?

ERIC Educational Resources Information Center

DuRant, Robert; Champion, Heather; Wolfson, Mark; Omli, Morrow; McCoy, Thomas; D'Agostino, Ralph B., Jr.; Wagoner, Kim; Mitra, Ananda

2007-01-01

Objective: The authors examined the clustering of health-risk behaviors among college students who reported date fight involvement. Participants and Methods: The authors administered a Web-based survey to a stratified random sample of 3,920 college students from 10 universities in North Carolina. Results: Among men, 5.6% reported date fight…

A Citation Analysis of Who's Who in Introductory Textbooks

ERIC Educational Resources Information Center

Griggs, Richard A.; Proctor, Derrick L.

2002-01-01

Given the many changes in the introductory psychology textbook market in the past 2 decades and the lack of a recent citation study of introductory texts, we conducted a citation analysis of a stratified random sample of current texts. To provide a more comprehensive picture of current citation emphases, we extended our analysis to the top 60…

An unconventional approach to ecosystem unit classification in western North Carolina, USA

Treesearch

W. Henry McNab; Sara A. Browning; Steven A. Simon; Penelope E. Fouts

1999-01-01

The authors used an unconventional combination of data transformation and multivariate analyses to reduce subjectivity in identification of ecosystem units in a mountainous region of western North Carolina, USA. Vegetative cover and environmental variables were measured on 79 stratified, randomly located, 0.1 ha sample plots in a 4000 ha watershed. Binary...

Understanding Intermediate-Level Speakers' Strengths and Weaknesses: An Examination of OPIc Tests from Korean Learners of English

ERIC Educational Resources Information Center

Cox, Troy L.

2017-01-01

This study profiled Intermediate-level learners in terms of their linguistic characteristics and performance on different proficiency tasks. A stratified random sample of 300 Korean learners of English with holistic ratings of Intermediate Low (IL), Intermediate Mid (IM), and Intermediate High (IH) on Oral Proficiency Interviews-computerized…

Development of Antisocial Personality Disorder in Detained Youths: The Predictive Value of Mental Disorders

ERIC Educational Resources Information Center

Washburn, Jason J.; Romero, Erin Gregory; Welty, Leah J.; Abram, Karen M.; Teplin, Linda A.; McClelland, Gary M.; Paskar, Leah D.

2007-01-01

Antisocial personality disorder (APD) is a serious public and mental health concern. Understanding how well conduct disorder (CD) and other mental disorders predict the development of APD among youths involved in the juvenile justice system is critical for prevention. The authors used a stratified random sample of 1,112 detained youths to examine…

Educational Service Quality in Zanjan University of Medical Sciences from Students' Point of View

ERIC Educational Resources Information Center

Mohammadi, Ali; Mohammadi, Jamshid

2014-01-01

This study aims at evaluating perceived service quality in Zanjan University of Medical Sciences (ZUMS). This study was cross-sectional and authors surveyed educational services at ZUMS. Through stratified random sampling, 384 students were selected and an adapted SERVQUAL instrument was used for data collection. Data analysis was performed by…

Teaching Effectiveness in Private Higher Education Institutions in Botswana: Analysis of Students' Perceptions

ERIC Educational Resources Information Center

Baliyan, Som Pal; Moorad, Fazlur Rehman

2018-01-01

This quantitative study analyzed the perceptions of students on teaching effectiveness in private higher education institutions in Botswana. An exploratory and descriptive survey research design was adopted in this study. A valid and reliable questionnaire was used to collect data through a survey of 560 stratified randomly sampled students in…

Students' and Human Rights Awareness in Secondary Schools' Environment in Delta State

ERIC Educational Resources Information Center

Akiri, Agharuwhe A.

2013-01-01

The paper reviewed the concept of human rights, possible origin and relevance to human society in general and the school system in particular. It evaluated people's level of awareness of these rights amongst students and teachers of secondary schools in Delta Central Senatorial District. The stratified random sampling technique was adopted to…

The Long-Term Effects of Florida's Third Grade Retention Policy

ERIC Educational Resources Information Center

Smith, Andre K.

2016-01-01

The purpose of this quantitative causal-comparative study was to evaluate the long-term effects of Florida's Third-Grade Retention policy on low performing students' subsequent academic performance as measured by FCAT reading scores. The study included a random stratified sample of 1500 retained third graders for failure to meet Florida's…

Do Human-Figure Drawings of Children and Adolescents Mirror Their Cognitive Style and Self-Esteem?

ERIC Educational Resources Information Center

Dey, Anindita; Ghosh, Paromita

2016-01-01

The investigation probed relationships among human-figure drawing, field-dependent-independent cognitive style and self-esteem of 10-15 year olds. It also attempted to predict human-figure drawing scores of participants based on their field-dependence-independence and self-esteem. Area, stratified and multi-stage random sampling were used to…

Implementation of Possession Laws and the Social Ecology of Tobacco Control

ERIC Educational Resources Information Center

Livingood, William C.; Woodhouse, Lynn D.; Wludyka, Peter

2009-01-01

The objective of this evaluation research was to assess the impact of programs intended to support the enforcement component of a comprehensive youth tobacco control. The research method was a survey of a randomly stratified cluster sample of law enforcement officers. Results of the evaluation showed that the enforcement behaviors of officers were…

Brain Hemisphericity and Mathematics Achievement of High School Students

ERIC Educational Resources Information Center

Fernandez, Sanny F.

2011-01-01

This study aimed to find out the brain hemisphericity and mathematics achievement of high school students. The respondents of the study were the 168 first year high school students of Colegio de San Jose, during school year 2010-2011 who were chosen through stratified random sampling. The descriptive and interview methods of research were used in…

An aging population: relationships between socio-demographics, motivations and participation

Treesearch

Karen Robinson; Robert C. Burns; Chad D. Pierskalla; Alan Graefe

2008-01-01

The purpose of this study was to examine the outdoor recreation behavior of Oregon's aging population, including developing a socio-demographic profile and examining the importance of their current motivations with the importance of their expected motivations 10 years from now. A stratified random sample was drawn of Oregon residents, and a mailback questionnaire...

The Degree of Symmetrical among the Teaching Staff at Tafila Technical University

ERIC Educational Resources Information Center

Kraimeen, Hani; Al-Hajaya, Suleiman

2017-01-01

The study was conducted to identify the degree of symmetrical among the teaching staff members at Tafila Technical University. The study community was comprised of all the 239 members of the teaching staff at Tafila Technical University. The study sample was selected by using the stratified random method according to the faculty variable which…

Level of Discipline among University Academic Staff as a Correlate of University Development in Nigeria

ERIC Educational Resources Information Center

Uhoman, Anyi Mary

2017-01-01

This study entitled "Level of Discipline Among University Academic Staff as a Correlate of University Development in Nigeria" adopted the correlation design with a population of 2,301 academic staff purposively selected from four Universities in the North-Central Geo-Political zone of Nigeria. The Stratified Random Sampling Method was…

Practising Mental Rotation Using Interactive Desktop Mental Rotation Trainer (iDeMRT)

ERIC Educational Resources Information Center

Rafi, Ahmad; Samsudin, Khairulanuar

2009-01-01

An experimental study involving 30 undergraduates (mean age = 20.5 years) in mental rotation (MR) training was conducted in an interactive Desktop Mental Rotation Trainer (iDeMRT). Stratified random sampling assigned students into one experimental group and one control group. The former trained in iDeMRT and the latter trained in conventional…

Focus Group Studies on Food Safety Knowledge, Perceptions, and Practices of School-Going Adolescent Girls in South India

ERIC Educational Resources Information Center

Gavaravarapu, Subba Rao M.; Vemula, Sudershan R.; Rao, Pratima; Mendu, Vishnu Vardhana Rao; Polasa, Kalpagam

2009-01-01

Objective: To understand food safety knowledge, perceptions, and practices of adolescent girls. Design: Focus group discussions (FGDs) with 32 groups selected using stratified random sampling. Setting: Four South Indian states. Participants: Adolescent girls (10-19 years). Phenomena of Interest: Food safety knowledge, perceptions, and practices.…

Factors That Predict Negative Versus Positive Addictions in Offspring: Are Dependent Exercisers Different Than Victims of Other Addictions?

ERIC Educational Resources Information Center

Manning, Terri M.

The study reported here assessed individuals' selection of excessive exercise dependent behaviors as they relate to self-esteem, family environment, and perceptions of family members exhibiting dysfunctional behaviors or addictions. A survey was taken of exercisers from a stratified random sample of competitive triathletes selected from the…

Culture, Motivation, and Vocational Decision-Making of Australian Senior High School Students in Private Schools

ERIC Educational Resources Information Center

Jung, Jae Yup; McCormick, John; Gregory, Gary; Barnett, Kerry

2011-01-01

The purpose of this study was to investigate the roles of culture and motivation in the occupational decisions of senior high school students attending private schools. A theoretical framework guided the study. A questionnaire was administered to 492 Grade 11 students attending a stratified random sample of six independent (private) schools…

WRITING SKILLS--ARE LARGE CLASSES CONDUCTIVE TO EFFECTIVE LEARNING.

ERIC Educational Resources Information Center

HOPPER, HAROLD H.; KELLER, HELEN

BY A STRATIFIED RANDOM SAMPLING, 274 STUDENTS WERE ASSIGNED TO THREE SECTIONS OF 56 STUDENTS EACH AND FOUR SECTIONS OF 28 STUDENTS. EVALUATION OF THE INSTRUCTION IN THE LARGE AND SMALL GROUPS INVOLVED ANALYSIS OF TWO ESSAYS AND INSTRUCTOR-STUDENT EVALUATIONS. WHILE THERE WAS SOME VARIATION IN STUDENT PREFERENCES, THE RESULTS OF THE PRETEST AND THE…

Evaluation of the Impact of Media Marketing Strategies on Continuing Education Enrollments. AIR Forum 1982 Paper.

ERIC Educational Resources Information Center

Campbell, Jill F.; Spiro, Louis M.

The impact of media marketing strategies on continuing education enrollment at the State University of New York College at Brockport (SUNY-CB), was evaluated. The evaluation of advertising impacts used advertising records of SUNY-CB and other area colleges and a telephone questionnaire instrument. A stratified, random countywide sample, in…

A Study of the Relationships between Distributed Leadership, Teacher Academic Optimism and Student Achievement in Taiwanese Elementary Schools

ERIC Educational Resources Information Center

Chang, I-Hua

2011-01-01

The purpose of this study was to explore the relationships between distributed leadership, teachers' academic optimism and student achievement in learning. The study targeted public elementary schools in Taiwan and adopted stratified random sampling to investigate 1500 teachers. Teachers' perceptions were collected by a self-report scale. In…

Investigating the Relationship between School Level and a School Growth Mindset

ERIC Educational Resources Information Center

Hanson, Janet; Ruff, William; Bangert, Arthur

2016-01-01

This study explored the relationship between school level and the psychosocial construct of a growth mindset school culture. Data was collected on the What's My School Mindset (WMSM) Survey from a stratified random sample of PK-12 faculty and administrators (n = 347) in 30 schools across a large northwestern state. The overarching research…

Precompetitive achievement goals, stress appraisals, emotions, and coping among athletes.

PubMed

Nicholls, Adam R; Perry, John L; Calmeiro, Luis

2014-10-01

Grounded in Lazarus's (1991, 1999, 2000) cognitive-motivational-relational theory of emotions, we tested a model of achievement goals, stress appraisals, emotions, and coping. We predicted that precompetitive achievement goals would be associated with appraisals, appraisals with emotions, and emotions with coping in our model. The mediating effects of emotions among the overall sample of 827 athletes and two stratified random subsamples were also explored. The results of this study support our proposed model in the overall sample and the stratified subsamples. Further, emotion mediated the relationship between appraisal and coping. Mediation analyses revealed that there were indirect effects of pleasant and unpleasant emotions, which indicates the importance of examining multiple emotions to reveal a more accurate representation of the overall stress process. Our findings indicate that both appraisals and emotions are just as important in shaping coping.

Examining an Alternative to Score Equating: A Randomly Equivalent Forms Approach. Research Report. ETS RR-08-14

ERIC Educational Resources Information Center

Liao, Chi-Wen; Livingston, Samuel A.

2008-01-01

Randomly equivalent forms (REF) of tests in listening and reading for nonnative speakers of English were created by stratified random assignment of items to forms, stratifying on item content and predicted difficulty. The study included 50 replications of the procedure for each test. Each replication generated 2 REFs. The equivalence of those 2…

Is a 'convenience' sample useful for estimating immunization coverage in a small population?

PubMed

Weir, Jean E; Jones, Carrie

2008-01-01

Rapid survey methodologies are widely used for assessing immunization coverage in developing countries, approximating true stratified random sampling. Non-random ('convenience') sampling is not considered appropriate for estimating immunization coverage rates but has the advantages of low cost and expediency. We assessed the validity of a convenience sample of children presenting to a travelling clinic by comparing the coverage rate in the convenience sample to the true coverage established by surveying each child in three villages in rural Papua New Guinea. The rate of DTF immunization coverage as estimated by the convenience sample was within 10% of the true coverage when the proportion of children in the sample was two-thirds or when only children over the age of one year were counted, but differed by 11% when the sample included only 53% of the children and when all eligible children were included. The convenience sample may be sufficiently accurate for reporting purposes and is useful for identifying areas of low coverage.

Feeding Tube Placement in Patients with Advanced Dementia: The Beliefs and Practice Patterns of Speech-Language Pathologists

ERIC Educational Resources Information Center

Sharp, Helen M.; Shega, Joseph W.

2009-01-01

Purpose: To describe the beliefs and practices of speech-language pathologists (SLPs) about the use of percutaneous endoscopic gastrostomy (PEG) among patients with advanced dementia and dysphagia. Method: A survey was mailed to a geographically stratified random sample of 1,050 medical SLPs. Results: The response rate was 57%, and 326 surveys met…

Outcomes of Parental Use of Psychological Aggression on Children: A Structural Model from Sri Lanka

ERIC Educational Resources Information Center

de Zoysa, Piyanjali; Newcombe, Peter A.; Rajapakse, Lalini

2010-01-01

The objective of this study was to explore the existence and, if so, the nature of the association between parental use of psychological aggression and psychological maladjustment in a 12-year-old Sri Lankan school population. A stratified random sampling technique was used to select 1,226 children from Colombo district schools. Three instruments,…

Effectiveness of a Test-Taking Strategy on Achievement in Essay Tests for Students with Learning Disabilities

ERIC Educational Resources Information Center

Therrien, William J.; Hughes, Charles; Kapelski, Cory; Mokhtari, Kouider

2009-01-01

Research was conducted to ascertain if an essay-writing strategy was effective at improving the achievement on essay tests for 7th- and 8th-grade students with reading and writing disabilities. Students were assigned via a stratified random sample to treatment or control group. Student scores were also compared to students without learning…

Commuters and Parking at UNC-G. Preliminary Findings from the Commuting Student Survey.

ERIC Educational Resources Information Center

Reichard, Donald J.; McArver, Patricia P.

Data gleaned from items relating to transportation and parking from the Commuting Student Survey are reported. The survey questionnaire was designed to provide an overview of several aspects of the commuting student's relationship with the university and was sent to a stratified random sample of 2,140 students who were enrolled for the spring 1975…

What Does Professional Rank Mean to Teachers? A Survey of the Multiple Impacts of Professional Rank on Urban and Rural Compulsory Education Teachers

ERIC Educational Resources Information Center

Yuyou, Qin; Wenjing, Zeng

2018-01-01

Professional rank is an important indicator of the professional capacity of compulsory education teachers. A rational professional rank evaluation system plays an important role in mobilizing the enthusiasm of teachers, improving the overall quality of teachers, and promoting the development of education. Based on stratified random sample data…

Demographic and Psychographic Variables Associated with Hispanic Business Majors Intending to Pursue Graduate Studies: Marketing Implications

ERIC Educational Resources Information Center

Adams, Russell; Kalliny, Morris; Saran, Anshu; de los Santos, Gilberto

2005-01-01

Increasing shifts in population proportions have led to an increasing demand on education institutions to recruit Hispanics. A random and stratified national sample was used to answer the following questions: (1) What are the psychographic typologies that are likely to identify Hispanic students by their desire to pursue or not to pursue graduate…

Dentists' Preferences for Diagnosis, Management and Referral of Chronic Oro-Facial Pain: Results from a National Survey

ERIC Educational Resources Information Center

Aggarwal, Vishal R.; Joughin, Amy; Zakrzewska, Joanna; Appelbe, Priscilla; Tickle, Martin

2012-01-01

Aim: To explore the diagnosis, treatment and referral patterns of chronic oro-facial pain patients by generalist primary care dentists (GDPs) in the UK. Methods: A cross-sectional survey was conducted using a non-stratified random sample of 500 GDPs who were selected from the General Dental Council register. A self-complete postal questionnaire…

The Invisible Student: A Longitudinal Study of the Beginning Freshman Class of 1963 at the University of New Mexico.

ERIC Educational Resources Information Center

Winther, Sven F.; And Others

The 1963 Freshman class at the University of New Mexico was studied through June, 1968, for performance patterns in relation to overall performance, high school grade-point average, male-female, Spanish surnames and non-Spanish surnames. In addition to university furnished data, questionnaires were submitted to a stratified random sample of…

Effect of Foreign Language Anxiety on Gender and Academic Achievement among Yemeni University EFL Students

ERIC Educational Resources Information Center

Razak, Norizan Abdul; Yassin, Amr Abdullatif; Maasum, Tengku Nor Rizan Bt Tengku Mohamad

2017-01-01

This study aimed to investigate the gender differences in terms of anxiety among Yemeni university EFL learners. It also aimed to investigate the correlation between the level of anxiety and the academic achievement of the students. The participants of this study were 155 students chosen from the population through stratified random sampling. The…

Student, Teacher, and Business Leader Perceptions of Academic, Work-Related, and Personal Skills in Rural Appalachian Communities.

ERIC Educational Resources Information Center

Bobbett, Gordon C.; And Others

The results of a study of six rural Appalachian high schools in Kentucky and Tennessee are presented. Multiple data sources were used to identify the relative effectiveness of these schools. Data were collected via administration of the: Wayson School Climate and Context Inventory to a stratified random sample of 20 faculty; Likert's…

Knowledge Level of Pre-Service Teachers in the Faculty of Education about Student Rights

ERIC Educational Resources Information Center

Topsakal, Cem

2012-01-01

As regards this study, it was aimed to determine the knowledge level of pre-service teachers in YYU faculty of education about student rights. The population of the study consisted of 3538 undergraduates in 2010-2011 academic year of YYU. By stratified and multi-phase sampling, 538 students from all departments and grades were randomly selected.…

Individual and Familial Correlates of Career Salience among Upwardly Mobile College Women. Final Report.

ERIC Educational Resources Information Center

Guttmacher, Mary Johnson

A case study was conducted using a sample of 271 women selected from a state college by a stratified random cluster technique that approximates proportional representation of women in all four classes and all college majors. The data source was an extensive questionnaire designed to measure the attitudes and behavior of interest. The major…

The Association of Health and Functional Status with Private and Public Religious Practice among Rural, Ethnically Diverse, Older Adults with Diabetes

ERIC Educational Resources Information Center

Arcury, Thomas A.; Stafford, Jeanette M.; Bell, Ronny A.; Golden, Shannon L.; Snively, Beverly M.; Quandt, Sara A.

2007-01-01

Purpose: This analysis describes the association of health and functional status with private and public religious practice among ethnically diverse (African American, Native American, white) rural older adults with diabetes. Methods: Data were collected using a population-based, cross-sectional, stratified, random sample survey of 701…

Effects of Training Method and Gender on Learning 2D/3D Geometry

ERIC Educational Resources Information Center

Khairulanuar, Samsudin; Nazre, Abd Rashid; Jamilah, H.; Sairabanu, Omar Khan; Norasikin, Fabil

2010-01-01

This article reports the findings of an experimental study involving 36 primary school students (16 girls, 20 boys, Mean age = 9.5 years, age range: 8-10 years) in geometrical understanding of 2D and 3D objects. Students were assigned into two experimental groups and one control group based on a stratified random sampling procedure. The first…

Self-Efficacy, Risk-Taking Behavior and Mental Health as Predictors of Personal Growth Initiative among University Undergraduates

ERIC Educational Resources Information Center

Ogunyemi, Ajibola O.; Mabekoje, Sesan Ola

2007-01-01

Introduction: This study sought to determine the combined and relative efficacy of self-efficacy, risk-taking behaviour and mental health on personal growth initiative of university undergraduates. Method: The expo-facto research design was used to conduct the study. Stratified random sampling technique was used to select 425 participants from 6…

Analysis of Teachers' Adoption of Technology for Use in Instruction in Seven Career and Technical Education Programs

ERIC Educational Resources Information Center

Kotrlik, Joe W.; Redmann, Donna H.

2009-01-01

This study addressed utilization of technology in instruction by secondary career and technical education (CTE) teachers in seven program areas in Louisiana. A stratified random sample was utilized, with 539 teachers responding to the survey after three data collection efforts. The data were determined to be representative of all CTE teachers in…

Assesment of Perceived Academic and Incentive Needs of Senior Secondary School Biology Teachers in Kwara State, Nigeria

ERIC Educational Resources Information Center

Ahmed, Mulkah Adebisi; Moradeyo, Ismail; Abimbola, Isaac Olakanmi

2016-01-01

The study investigated the Assessment of perceived academic and incentive needs of senior secondary school biology teachers in Kwara State, Nigeria. Stratified random sampling technique was used to select two hundred and fifty (250) biology teachers from the three senatorial district of Kwara State. A questionnaire was prepared, validated and used…

Assessing change in large-scale forest area by visually interpreting Landsat images

Treesearch

Jerry D. Greer; Frederick P. Weber; Raymond L. Czaplewski

2000-01-01

As part of the Forest Resources Assessment 1990, the Food and Agriculture Organization of the United Nations visually interpreted a stratified random sample of 117 Landsat scenes to estimate global status and change in tropical forest area. Images from 1980 and 1990 were interpreted by a group of widely experienced technical people in many different tropical countries...

Socio-Psychological Correlates of Non-Medical Use of Drugs Among University Students.

ERIC Educational Resources Information Center

Mehra, N.

This study was designed to collect and analyze study reactions on a broad range of social, cultural and educational issues including the nonmedical use of drugs. Two questionnaires and a personality inventory were used in the collection of data that was obtained from a stratified random sample of 282 students of the University of Alberta. An…

Restrictive Access to Books in School Library Media Centers in Georgia. Research Study.

ERIC Educational Resources Information Center

DuPree, Vi

This study sought to determine the extent of restrictive access to books in Georgia school library media centers and to discover by whose authority and for what reason these books might be placed on restrictive shelves. Questionnaires were completed and received from a stratified random sampling of 119 media specialists in high schools, middle or…

The Effect of School Bureaucracy on the Relationship between Principals' Leadership Practices and Teacher Commitment in Malaysia Secondary Schools

ERIC Educational Resources Information Center

Kean, Teoh Hong; Kannan, Sathiamoorthy; Piaw, Chua Yan

2017-01-01

The main aim of this research paper was to ascertain the relationship between principal leadership practices and teacher commitment. The study was conducted using quantitative survey questionnaire to 384 secondary school teachers, ranging from band 1 to band 6 in Malaysia using multi stage stratified cluster random sampling. This study was using…

Bridging the Gap: A Longitudinal Study of the Relationship between Pedagogical Continuity and Early Chinese Literacy Acquisition

ERIC Educational Resources Information Center

Li, Hui; Rao, Nirmala; Tse, Shek Kam

2011-01-01

This longitudinal study examined the relationship between pedagogical continuity in literacy education and early literacy development by comparing Chinese children in Hong Kong and Shenzhen. Stratified random sampling was used to select 24 preschool and Primary 1 classes in four communities catering to middle-class families in each city. The 24…

Wisconsin Youth Risk Behavior Survey. Executive Summary and Report.

ERIC Educational Resources Information Center

Sloan, Matt

The 1999 Wisconsin Youth Risk Behavior Survey (YRBS) was conducted as part of a national survey effort by the U.S. Centers for Disease Control and Prevention. A stratified random sample of classrooms in all public schools with ninth through twelfth grades was taken. The YRBS was administered to 1,336 students in 46 public schools in Wisconsin in…

Correlates to Human Papillomavirus Vaccination Status and Willingness to Vaccinate in Low-Income Philadelphia High School Students

ERIC Educational Resources Information Center

Bass, Sarah B.; Leader, Amy; Shwarz, Michelle; Greener, Judith; Patterson, Freda

2015-01-01

Background: Little is known about the correlates of human papillomavirus (HPV) vaccination or willingness to be vaccinated in urban, minority adolescents. Methods: Using responses to the 2013 Youth Risk Behavior Survey in Philadelphia, a random sample of high schools provided weighted data representing 20,941 9th to 12th graders. Stratified by…

Scholars' Satisfaction with Digital Library Collection and Gaps in the Provision of Effective Information Resources and Services: A Pakistani Perspective

ERIC Educational Resources Information Center

Khan, Amjid; Ahmed, Shamshad; Masrek, Mohamad Noorman

2014-01-01

The study aims to explore the researchers' satisfaction with digital library resources and services and how they improved the research culture in Pakistani universities. A descriptive survey method was employed to achieve objectives of this study. Using stratified random sampling, for this survey we selected 14 public sector universities of Khyber…

Trajectories of Familism Values and the Prosocial Tendencies of Mexican American Adolescents

ERIC Educational Resources Information Center

Knight, George P.; Mazza, Gina L.; Carlo, Gustavo

2018-01-01

We examined how the development of familism values from 5th to 10th grade relates to 12th-grade prosocial tendencies (after controlling for 10th-grade prosocial tendencies) using a stratified random sample of 749 Mexican American adolescents (M = 10.42 years of age at 5th grade; 48.9% girls) from 35 culturally and economically diverse…

Effects of Mayfield's Four Questions (M4Q) on Nursing Students' Self-Efficacy and Multiple-Choice Test Scores

ERIC Educational Resources Information Center

Mayfield, Linda Riggs

2010-01-01

This study examined the effects of being taught the Mayfield's Four Questions multiple-choice test-taking strategy on the perceived self-efficacy and multiple-choice test scores of nursing students in a two-year associate degree program. Experimental and control groups were chosen by stratified random sampling. Subjects completed the 10-statement…

'Pygmy' old-growth redwood characteristics on an edaphic ecotone in Mendocino County, California

Treesearch

Will Russell; Suzie. Woolhouse

2012-01-01

The 'pygmy forest' is a specialized community that is adapted to highly acidic, hydrophobic, nutrient deprived soils, and exists in pockets within the coast redwood forest in Mendocino County. While coast redwood is known as an exceptionally tall tree, stunted trees exhibit unusual growth-forms on pygmy soils. We used a stratified random sampling procedure to...

Teachers' Opinions on the Incorporation of Environmental Education in the Nigerian Primary School Curriculum

ERIC Educational Resources Information Center

Jekayinfa, Alice Arinlade; Yusuf, Abdul Raheem

2008-01-01

This paper presents the report of a research carried out in Kwara Sate of Nigeria to seek the opinions of teachers on the incorporation of Environmental Education (EE) in the Nigerian Primary School Curriculum. The descriptive survey method was employed for the study. 200 teachers were selected through stratified random sampling technique to cater…

The Influence of Instructional Minutes on Grade 11 Language Arts and Mathematics High School Proficiency Assessment Performance

ERIC Educational Resources Information Center

Welcome, Simone E.

2017-01-01

The purpose for this cross-sectional, non-experimental explanatory quantitative research study was to explain the amount of variance in the High School Proficiency Assessment-11 Language Arts and Mathematics scores accounted for by the amount of instructional minutes at high schools in New Jersey. A proportional, stratified random sample which…

Measures and Predictors of Educational Growth with Four Years of College. AIR Forum 1980 Paper.

ERIC Educational Resources Information Center

Dumont, Richard G.; Troelstrup, Richard L.

Use of the American College Testing (ACT) Program assessment battery for the measurement of student growth at a regional state university is described. A stratified random sample of 112 seniors at Tennessee Technological University was given the residual form of the ACT Assessment battery for comparison with their pre-college ACT test performance.…

Prevalence Incidence Mixture Models

Cancer.gov

The R package and webtool fits Prevalence Incidence Mixture models to left-censored and irregularly interval-censored time to event data that is commonly found in screening cohorts assembled from electronic health records. Absolute and relative risk can be estimated for simple random sampling, and stratified sampling (the two approaches of superpopulation and a finite population are supported for target populations). Non-parametric (absolute risks only), semi-parametric, weakly-parametric (using B-splines), and some fully parametric (such as the logistic-Weibull) models are supported.

Using maximum entropy modeling for optimal selection of sampling sites for monitoring networks

USGS Publications Warehouse

Stohlgren, Thomas J.; Kumar, Sunil; Barnett, David T.; Evangelista, Paul H.

2011-01-01

Environmental monitoring programs must efficiently describe state shifts. We propose using maximum entropy modeling to select dissimilar sampling sites to capture environmental variability at low cost, and demonstrate a specific application: sample site selection for the Central Plains domain (453,490 km2) of the National Ecological Observatory Network (NEON). We relied on four environmental factors: mean annual temperature and precipitation, elevation, and vegetation type. A “sample site” was defined as a 20 km × 20 km area (equal to NEON’s airborne observation platform [AOP] footprint), within which each 1 km2 cell was evaluated for each environmental factor. After each model run, the most environmentally dissimilar site was selected from all potential sample sites. The iterative selection of eight sites captured approximately 80% of the environmental envelope of the domain, an improvement over stratified random sampling and simple random designs for sample site selection. This approach can be widely used for cost-efficient selection of survey and monitoring sites.

Latin Hypercube Sampling (LHS) UNIX Library/Standalone

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

2004-05-13

The LHS UNIX Library/Standalone software provides the capability to draw random samples from over 30 distribution types. It performs the sampling by a stratified sampling method called Latin Hypercube Sampling (LHS). Multiple distributions can be sampled simultaneously, with user-specified correlations amongst the input distributions, LHS UNIX Library/ Standalone provides a way to generate multi-variate samples. The LHS samples can be generated either as a callable library (e.g., from within the DAKOTA software framework) or as a standalone capability. LHS UNIX Library/Standalone uses the Latin Hypercube Sampling method (LHS) to generate samples. LHS is a constrained Monte Carlo sampling scheme. Inmore » LHS, the range of each variable is divided into non-overlapping intervals on the basis of equal probability. A sample is selected at random with respect to the probability density in each interval, If multiple variables are sampled simultaneously, then values obtained for each are paired in a random manner with the n values of the other variables. In some cases, the pairing is restricted to obtain specified correlations amongst the input variables. Many simulation codes have input parameters that are uncertain and can be specified by a distribution, To perform uncertainty analysis and sensitivity analysis, random values are drawn from the input parameter distributions, and the simulation is run with these values to obtain output values. If this is done repeatedly, with many input samples drawn, one can build up a distribution of the output as well as examine correlations between input and output variables.« less

Shrub succession on eight mixed-severity wildfires in western Montana, northeastern Oregon, and northern Idaho

Treesearch

Dennis E. Ferguson; John C. Byrne

2016-01-01

The response of 28 shrub species to wildfire burn severity was assessed for 8 wildfires on 6 national forests in the northern Rocky Mountains, USA. Stratified random sampling was used to choose 224 stands based on burn severity, habitat type series, slope steepness, stand height, and stand density, which resulted in 896 plots measured at approximately 2-year intervals...

The Ambivalence of the Israeli Academic Profession: Research vs. Teaching. The Academic Profession Approaches the Twenty-First Century: the Carnegie Foundation International Survey, Symposium.

ERIC Educational Resources Information Center

Gottlieb, Esther E.; And Others

Attitudes of Israeli senior faculty concerning research and teaching were evaluated using the Carnegie international questionnaire. Approximately one third of the total faculty population in Israel was randomly sampled, but stratified by institutional size. The questionnaire was sent to 2,225 faculty and 502 returned completed forms (22.56…

Gender Differences and Public Sector Managers: Women's Perceptions of Equality in State Government.

ERIC Educational Resources Information Center

Whitcraft, Carol; Williams, M. Lee

A study assessed the equality of women managers in 11 of the largest state agencies in Texas. It also investigated the perceptions of men and women managers concerning a variety of work related issues in Texas state government. A stratified random sample of 25 percent of all managers was drawn, and 1,844 responses, representing a 55.5% response…

Teachers Use of Writing to Support Students' Learning in Middle School: A National Survey in the United States

ERIC Educational Resources Information Center

Ray, Amber B.; Graham, Steve; Houston, Julia D.; Harris, Karen R.

2016-01-01

A random sample of middle school teachers (grades 6-9) from across the United States was surveyed about their use of writing to support students' learning. The selection process was stratified so there were an equal number of English language arts, social studies, and science teachers. More than one-half of the teachers reported applying 15 or…

The Davis Social Environment-1990: A Report of Student Opinions.

ERIC Educational Resources Information Center

Low, Jane M.

A study was done to examine student opinion of the social environment on the University of California Davis campus in Spring 1990 as a follow up to a similar study conducted in 1987. The study used the Student Opinion Survey and mailed it to a stratified random sample of 1,649 students. Of the surveys sent, 57.7 percent were returned. The…

Public Perceptions of Agriculture: The Role of Government, Support for the Family Farm and Support of Domestic Food Programs.

ERIC Educational Resources Information Center

Mu'min, Ridgely A.; And Others

There are few racial or urban/rural differences in public attitudes toward agriculture and government agricultural policies. The Farming in American Life Study, a collaborative effort by 14 land grant institutions in the South and Midwest, gathered 3,239 completed questionnaires from a national stratified random sample for a completion rate of 46…

Do Children Who Bully Their Peers Also Play Violent Video Games? A Canadian National Study

ERIC Educational Resources Information Center

Dittrick, Crystal J.; Beran, Tanya N.; Mishna, Faye; Hetherington, Ross; Shariff, Shaheen

2013-01-01

The study examined whether children who bully others are likely to prefer playing video games that are rated high in maturity and violence. A stratified random sample of Canadian children ages 10 to 17 years from the provinces of Canada was obtained. Parents (n = 397) and their children (n = 492) completed an online survey of children's bullying…

Effects of low intensity prescribed fires on ponderosa pine forests in wilderness areas of Zion National Park, Utah

Treesearch

Henry V. Bastian

2001-01-01

Vegetation and fuel loading plots were monitored and sampled in wilderness areas treated with prescribed fire. Changes in ponderosa pine (Pinus ponderosa) forest structure tree species and fuel loading are presented. Plots were randomly stratified and established in burn units in 1995. Preliminary analysis of nine plots 2 years after burning show litter was reduced 54....

Validity of the Child Observation Record: An Investigation of the Relationship between Cor Dimensions and Social-Emotional and Cognitive Outcomes for Head Start Children

ERIC Educational Resources Information Center

Sekino, Yumiko; Fantuzzo, John

2005-01-01

The study examined the validity of the Child Observation Record (COR). Participants were 242 children, a stratified, random sample of a large, urban Head Start program. Teachers trained to collect COR data provided assessments on the Cognitive, Social Engagement, and Coordinated Movement dimensions of the COR. Outcome data included cognitive and…

The Psychological Effect of Errors in Standardized Language Test Items on EFL Students' Responses to the Following Item

ERIC Educational Resources Information Center

Khaksefidi, Saman

2017-01-01

This study investigates the psychological effect of a wrong question with wrong items on answering to the next question in a test of structure. Forty students selected through stratified random sampling are given 15 questions of a standardized test namely a TOEFL structure test in which questions number 7 and number 11 are wrong and their answers…

Graduate Science Enrollment in Fall 1975 is Up Again for Second Straight Year. Science Resources Studies Highlights, December 31, 1975.

ERIC Educational Resources Information Center

National Science Foundation, Washington, DC. Div. of Science Resources Studies.

This report is based upon the National Science Foundation (NSF) 1975 Quick Response Survey which consisted of a stratified random sample of l,297 departments in 294 institutions (including 67 medical schools) granting a Ph.D. in science or engineering. Variables investigated were: (1) area of science, (2) full-time enrollment number, (3) part-time…

A Comparative Study of Students' Access to and Utilization of Learning Resources in Selected Public and Private Universities in Southwest, Nigeria

ERIC Educational Resources Information Center

Lawal, B. O.; Viatonu, Olumuyiwa

2017-01-01

The study investigated students' access to and utilization of some learning resources in selected public and private universities in southwest Nigeria. Stratified random sampling technique was used to select 585 (295 public and 290 private) students from 12 (six public and six private) universities in southwest Nigeria. Two instruments--Cost and…

The Needs of Tribal Men and the Social Service Providers on or Near the Nez Perce Indian Nation.

ERIC Educational Resources Information Center

High Eagle, Gordon; And Others

This report results from an action research project of the Nee Mee Poom Ha Hum (Men's Coalition), investigating the needs of tribal men in the Nez Perce Indian Nation, as part of planning to improve men's development. Research was directed toward interviewing a stratified random sample of tribal men and interviewing the directors and employees of…

Relationship between Staff-Reported Culture Change and Occupancy Rate and Organizational Commitment among Nursing Homes in South Korea

ERIC Educational Resources Information Center

Lee, Minhong; Choi, Jae-Sung; Lim, Jinseop; Kim, Young Sun

2013-01-01

Purpose: This study aims to examine culture change in nursing homes in South Korea and to identify the outcomes of culture change implementation. Design and Methods: Data were taken from survey responses from 223 top- or mid-level staff among nursing homes in South Korea that were selected through a proportionate random-stratified sampling method…

Children Without Homes: An Examination of Public Responsibility to Children in Out-of-Home Care.

ERIC Educational Resources Information Center

Knitzer, Jane; And Others

This book is the seventh Children's Defense Fund report on major problems facing American children at risk of placement or already placed out of their homes. The findings are based on a survey of child welfare and probation offices in a stratified random sample of 140 counties (27 with populations over 300,000, and 113 with populations under…

Re-Engineering Vocational and Technical Education (VTE) for Sustainable Development in North Central Geo-Political Zone, Nigeria

ERIC Educational Resources Information Center

Sofoluwe, Abayomi Olumade

2013-01-01

The purpose of the study is to re-engineer vocational and technical education for sustainable development in the North Central Geo-Political Zone in Nigeria. The research design adopted was a survey inferential type. Stratified random was used to select 36 schools out of 98 schools while 920 students out of 3680 students were sampled. The data…

Geostatistical Sampling Methods for Efficient Uncertainty Analysis in Flow and Transport Problems

NASA Astrophysics Data System (ADS)

Liodakis, Stylianos; Kyriakidis, Phaedon; Gaganis, Petros

2015-04-01

In hydrogeological applications involving flow and transport of in heterogeneous porous media the spatial distribution of hydraulic conductivity is often parameterized in terms of a lognormal random field based on a histogram and variogram model inferred from data and/or synthesized from relevant knowledge. Realizations of simulated conductivity fields are then generated using geostatistical simulation involving simple random (SR) sampling and are subsequently used as inputs to physically-based simulators of flow and transport in a Monte Carlo framework for evaluating the uncertainty in the spatial distribution of solute concentration due to the uncertainty in the spatial distribution of hydraulic con- ductivity [1]. Realistic uncertainty analysis, however, calls for a large number of simulated concentration fields; hence, can become expensive in terms of both time and computer re- sources. A more efficient alternative to SR sampling is Latin hypercube (LH) sampling, a special case of stratified random sampling, which yields a more representative distribution of simulated attribute values with fewer realizations [2]. Here, term representative implies realizations spanning efficiently the range of possible conductivity values corresponding to the lognormal random field. In this work we investigate the efficiency of alternative methods to classical LH sampling within the context of simulation of flow and transport in a heterogeneous porous medium. More precisely, we consider the stratified likelihood (SL) sampling method of [3], in which attribute realizations are generated using the polar simulation method by exploring the geometrical properties of the multivariate Gaussian distribution function. In addition, we propose a more efficient version of the above method, here termed minimum energy (ME) sampling, whereby a set of N representative conductivity realizations at M locations is constructed by: (i) generating a representative set of N points distributed on the surface of a M-dimensional, unit radius hyper-sphere, (ii) relocating the N points on a representative set of N hyper-spheres of different radii, and (iii) transforming the coordinates of those points to lie on N different hyper-ellipsoids spanning the multivariate Gaussian distribution. The above method is applied in a dimensionality reduction context by defining flow-controlling points over which representative sampling of hydraulic conductivity is performed, thus also accounting for the sensitivity of the flow and transport model to the input hydraulic conductivity field. The performance of the various stratified sampling methods, LH, SL, and ME, is compared to that of SR sampling in terms of reproduction of ensemble statistics of hydraulic conductivity and solute concentration for different sample sizes N (numbers of realizations). The results indicate that ME sampling constitutes an equally if not more efficient simulation method than LH and SL sampling, as it can reproduce to a similar extent statistics of the conductivity and concentration fields, yet with smaller sampling variability than SR sampling. References [1] Gutjahr A.L. and Bras R.L. Spatial variability in subsurface flow and transport: A review. Reliability Engineering & System Safety, 42, 293-316, (1993). [2] Helton J.C. and Davis F.J. Latin hypercube sampling and the propagation of uncertainty in analyses of complex systems. Reliability Engineering & System Safety, 81, 23-69, (2003). [3] Switzer P. Multiple simulation of spatial fields. In: Heuvelink G, Lemmens M (eds) Proceedings of the 4th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences, Coronet Books Inc., pp 629?635 (2000).

A methodology for small scale rural land use mapping in semi-arid developing countries using orbital imagery. Part 5: Experimental and operational techniques of mapping land use

NASA Technical Reports Server (NTRS)

Vangenderen, J. L. (Principal Investigator); Lock, B. F.

1976-01-01

The author has identified the following significant results. Scope of the preprocessing techniques was restricted to standard material from the EROS Data Center accompanied by some enlarging procedures and the use of the diazo process. Investigation has shown that the most appropriate sampling strategy for this study is the stratified random technique. A viable sampling procedure, together with a method for determining minimum number of sample points in order to test results of any interpretation are presented.

Community Clinicians and the Veterans Choice Program for PTSD Care: Understanding Provider Interest During Early Implementation.

PubMed

Finley, Erin P; Noël, Polly H; Mader, Michael; Haro, Elizabeth; Bernardy, Nancy; Rosen, Craig S; Bollinger, Mary; Garcia, Hector; Sherrieb, Kathleen; Pugh, Mary Jo V

2017-07-01

In 2014, the Department of Veterans Affairs (VA) implemented the Veterans Choice Program (VCP) to provide reimbursement for community-based care to eligible veterans. Inadequate networks of participating providers may impact the utility of VCP for veterans with posttraumatic stress disorder (PTSD), a complex condition occurring at lower frequency among civilians. To compare characteristics and attitudes of community-based primary care and mental health providers reporting interest or no interest in VCP participation during early implementation; and to examine perceptions and experiences of VCP among "early adopters." Cross-sectional surveys with 2 samples: a stratified random sample of mental health and primary care prescribers and psychotherapists drawn from state licensing boards (Community Sample); and a stratified random sample of prescribers and psychotherapists identified as VCP-authorized providers (VCP-Authorized). Five hundred fifty-three respondents in the Community Sample and 115 in the VCP-Authorized (total, n=668; 21.1% response). Surveys assessed provider and practice characteristics, attitudes to VA and VCP, and experiences and satisfaction with the VCP; an open-ended survey item assessed providers' reasons for interest or lack of interest in VCP participation. Few providers reported VCP participation during this period. Interest in VCP participation was associated across provider groups with factors including being a veteran and receiving VA reimbursement; currently providing treatment for PTSD was associated with interest in VCP participation among psychotherapists, but not prescribers. Developing networks of VCP providers to serve Veterans with PTSD is likely to require targeting more receptive provider groups, reducing barriers to participation, and more effectively communicating the value of VCP participation to providers.

Influences of sampling size and pattern on the uncertainty of correlation estimation between soil water content and its influencing factors

NASA Astrophysics Data System (ADS)

Lai, Xiaoming; Zhu, Qing; Zhou, Zhiwen; Liao, Kaihua

2017-12-01

In this study, seven random combination sampling strategies were applied to investigate the uncertainties in estimating the hillslope mean soil water content (SWC) and correlation coefficients between the SWC and soil/terrain properties on a tea + bamboo hillslope. One of the sampling strategies is the global random sampling and the other six are the stratified random sampling on the top, middle, toe, top + mid, top + toe and mid + toe slope positions. When each sampling strategy was applied, sample sizes were gradually reduced and each sampling size contained 3000 replicates. Under each sampling size of each sampling strategy, the relative errors (REs) and coefficients of variation (CVs) of the estimated hillslope mean SWC and correlation coefficients between the SWC and soil/terrain properties were calculated to quantify the accuracy and uncertainty. The results showed that the uncertainty of the estimations decreased as the sampling size increasing. However, larger sample sizes were required to reduce the uncertainty in correlation coefficient estimation than in hillslope mean SWC estimation. Under global random sampling, 12 randomly sampled sites on this hillslope were adequate to estimate the hillslope mean SWC with RE and CV ≤10%. However, at least 72 randomly sampled sites were needed to ensure the estimated correlation coefficients with REs and CVs ≤10%. Comparing with all sampling strategies, reducing sampling sites on the middle slope had the least influence on the estimation of hillslope mean SWC and correlation coefficients. Under this strategy, 60 sites (10 on the middle slope and 50 on the top and toe slopes) were enough to ensure the estimated correlation coefficients with REs and CVs ≤10%. This suggested that when designing the SWC sampling, the proportion of sites on the middle slope can be reduced to 16.7% of the total number of sites. Findings of this study will be useful for the optimal SWC sampling design.

Stratifying to reduce bias caused by high nonresponse rates: A case study from New Mexico’s forest inventory

Treesearch

Sara A. Goeking; Paul L. Patterson

2013-01-01

The USDA Forest Service’s Forest Inventory and Analysis (FIA) Program applies specific sampling and analysis procedures to estimate a variety of forest attributes. FIA’s Interior West region uses post-stratification, where strata consist of forest/nonforest polygons based on MODIS imagery, and assumes that nonresponse plots are distributed at random across each stratum...

Response of six non-native invasive plant species to wildfires in the northern Rocky Mountains, USA

Treesearch

Dennis E. Ferguson; Christine L. Craig

2010-01-01

This paper presents early results on the response of six non-native invasive plant species to eight wildfires on six National Forests (NFs) in the northern Rocky Mountains, USA. Stratified random sampling was used to choose 224 stands based on burn severity, habitat type series, slope steepness, stand height, and stand density. Data for this report are from 219 stands...

A Description of the Building Materials Data Base for Portland, Maine.

DTIC Science & Technology

1986-06-01

WORDS (Continue on reveree side if neceseary and Identify by block number)". Acid precipitation, , Data bases, Damage assessment, Environmental...protection) Damage from acid deposition, Portland, Maine Damage to buildings, - Statistical analysis, . 20. ASsrRACT (Conlaue a reverse e(A It n -cwery md...types and amounts of building surface materials ex- posed to acid deposition. The stratified, systematic, unaligned random sampling approach was used

Accuracy assessments and areal estimates using two-phase stratified random sampling, cluster plots, and the multivariate composite estimator

Treesearch

Raymond L. Czaplewski

2000-01-01

Consider the following example of an accuracy assessment. Landsat data are used to build a thematic map of land cover for a multicounty region. The map classifier (e.g., a supervised classification algorithm) assigns each pixel into one category of land cover. The classification system includes 12 different types of forest and land cover: black spruce, balsam fir,...

The use of single-date MODIS imagery for estimating large-scale urban impervious surface fraction with spectral mixture analysis and machine learning techniques

NASA Astrophysics Data System (ADS)

Deng, Chengbin; Wu, Changshan

2013-12-01

Urban impervious surface information is essential for urban and environmental applications at the regional/national scales. As a popular image processing technique, spectral mixture analysis (SMA) has rarely been applied to coarse-resolution imagery due to the difficulty of deriving endmember spectra using traditional endmember selection methods, particularly within heterogeneous urban environments. To address this problem, we derived endmember signatures through a least squares solution (LSS) technique with known abundances of sample pixels, and integrated these endmember signatures into SMA for mapping large-scale impervious surface fraction. In addition, with the same sample set, we carried out objective comparative analyses among SMA (i.e. fully constrained and unconstrained SMA) and machine learning (i.e. Cubist regression tree and Random Forests) techniques. Analysis of results suggests three major conclusions. First, with the extrapolated endmember spectra from stratified random training samples, the SMA approaches performed relatively well, as indicated by small MAE values. Second, Random Forests yields more reliable results than Cubist regression tree, and its accuracy is improved with increased sample sizes. Finally, comparative analyses suggest a tentative guide for selecting an optimal approach for large-scale fractional imperviousness estimation: unconstrained SMA might be a favorable option with a small number of samples, while Random Forests might be preferred if a large number of samples are available.

Toward cost-efficient sampling methods

NASA Astrophysics Data System (ADS)

Luo, Peng; Li, Yongli; Wu, Chong; Zhang, Guijie

2015-09-01

The sampling method has been paid much attention in the field of complex network in general and statistical physics in particular. This paper proposes two new sampling methods based on the idea that a small part of vertices with high node degree could possess the most structure information of a complex network. The two proposed sampling methods are efficient in sampling high degree nodes so that they would be useful even if the sampling rate is low, which means cost-efficient. The first new sampling method is developed on the basis of the widely used stratified random sampling (SRS) method and the second one improves the famous snowball sampling (SBS) method. In order to demonstrate the validity and accuracy of two new sampling methods, we compare them with the existing sampling methods in three commonly used simulation networks that are scale-free network, random network, small-world network, and also in two real networks. The experimental results illustrate that the two proposed sampling methods perform much better than the existing sampling methods in terms of achieving the true network structure characteristics reflected by clustering coefficient, Bonacich centrality and average path length, especially when the sampling rate is low.

Spatial inventory integrating raster databases and point sample data. [Geographic Information System for timber inventory

NASA Technical Reports Server (NTRS)

Strahler, A. H.; Woodcock, C. E.; Logan, T. L.

1983-01-01

A timber inventory of the Eldorado National Forest, located in east-central California, provides an example of the use of a Geographic Information System (GIS) to stratify large areas of land for sampling and the collection of statistical data. The raster-based GIS format of the VICAR/IBIS software system allows simple and rapid tabulation of areas, and facilitates the selection of random locations for ground sampling. Algorithms that simplify the complex spatial pattern of raster-based information, and convert raster format data to strings of coordinate vectors, provide a link to conventional vector-based geographic information systems.

Correcting Classifiers for Sample Selection Bias in Two-Phase Case-Control Studies

PubMed Central

Theis, Fabian J.

2017-01-01

Epidemiological studies often utilize stratified data in which rare outcomes or exposures are artificially enriched. This design can increase precision in association tests but distorts predictions when applying classifiers on nonstratified data. Several methods correct for this so-called sample selection bias, but their performance remains unclear especially for machine learning classifiers. With an emphasis on two-phase case-control studies, we aim to assess which corrections to perform in which setting and to obtain methods suitable for machine learning techniques, especially the random forest. We propose two new resampling-based methods to resemble the original data and covariance structure: stochastic inverse-probability oversampling and parametric inverse-probability bagging. We compare all techniques for the random forest and other classifiers, both theoretically and on simulated and real data. Empirical results show that the random forest profits from only the parametric inverse-probability bagging proposed by us. For other classifiers, correction is mostly advantageous, and methods perform uniformly. We discuss consequences of inappropriate distribution assumptions and reason for different behaviors between the random forest and other classifiers. In conclusion, we provide guidance for choosing correction methods when training classifiers on biased samples. For random forests, our method outperforms state-of-the-art procedures if distribution assumptions are roughly fulfilled. We provide our implementation in the R package sambia. PMID:29312464

Financing Adult Education: How Adequate Are Current Sources in Facilitating Access and Participation in Centres in Murang'a South Sub-County, Murang'a County, Kenya?

ERIC Educational Resources Information Center

Maina, Ndonga James; Orodho, John Aluko

2016-01-01

The thrust of this study was to examine the level of adequacy of current sources in facilitating access and participation in adult education centres in Murang'a South Sub-County, Murang'a County, Kenya. The study adopted the descriptive survey design. Combinations of purposive and stratified random sampling techniques were used to select 82…

Teacher Education, Motivation, Compensation, Workplace Support, and Links to Quality of Center-Based Child Care and Teachers' Intention to Stay in the Early Childhood Profession

ERIC Educational Resources Information Center

Torquati, Julia C.; Raikes, Helen; Huddleston-Casas, Catherine A.

2007-01-01

The purposes of this study were to present a conceptual model for selection into the early childhood profession and to test the model using contemporaneous assessments. A stratified random sample of center-based child care providers in 4 Midwestern states (n=964) participated in a telephone interview, and 223 were also assessed with the Early…

Effect of initial spacing on mechanical properties of lumber sawn from unthinned slash pine at age 40

Treesearch

Robert H. McAlister; Alexander Clark; Joseph R. Saucier

1997-01-01

The effect of initial planting density on strength and stiffness of slash pine (Pinus elliotti Engelm. var elliotti) from a 40-year-old plantation on the Georgia Coastal Plain was examined. A stratified random sample of trees with diameters at breast height ranging from 8 to 16 inches from replicated stands representing tree spacing of 6 by 8, 8 by 8, 10 by 10, and 15...

A Comparative Study of the Academic Stress and Depression among High School Girl and Boy Students

ERIC Educational Resources Information Center

Khanehkeshi, Ali; Basavarajappa

2012-01-01

This paper compares the difference between boy and girl high school students of 1st grade to 3rd grade in academic stress and depression. Using a random stratified sampling 120 girl and boy students (60 girls and 60 boys) were selected from 1st grade (n = 40), 2nd grade (n = 40) and 3rd grade (n = 40) high school students. In this study gender and…

The Effectiveness of Using Brainstorming Strategy in the Development of Academic Achievement of Sixth Grade Students in English Grammar at Public Schools in Jordan

ERIC Educational Resources Information Center

Malkawi, Nibal Abdelkarim Mousa; Smadi, Mona

2018-01-01

The study aims to identify the effect of using brainstorming method in the teaching of English grammar; to improve the level of sixth grade students in English grammar at public schools in Jordan. The study population consisted of all sixth grade students of both sexes. The sample of the study was chosen in the random stratified manner,…

The Utility of Discriminant Analysis for Predicting Farmers' Intentions to Participate in Farmer-Managed Irrigation Systems in Iran

NASA Astrophysics Data System (ADS)

Zarafshani, Kiumars; Hossien Alibaygi, Amir; Afshar, Nasrin

Participatory irrigation management has been problematic in most parts of the world and Iran has been no exception. The purpose of this study was to assess farmers' intentions to participate in irrigation management based on selected variables using discriminant analysis. A survey questionnaire was used to collect information from a sample of Water Cooperatives in Javanrood Townships using stratified random sampling (n = 106). Results indicated that age, educational level, attitude towards PIM, irrigation performance, landholding size, agricultural and non-agricultural income affected farmers' intentions to participate in irrigation management.

Use of simulation to compare the performance of minimization with stratified blocked randomization.

PubMed

Toorawa, Robert; Adena, Michael; Donovan, Mark; Jones, Steve; Conlon, John

2009-01-01

Minimization is an alternative method to stratified permuted block randomization, which may be more effective at balancing treatments when there are many strata. However, its use in the regulatory setting for industry trials remains controversial, primarily due to the difficulty in interpreting conventional asymptotic statistical tests under restricted methods of treatment allocation. We argue that the use of minimization should be critically evaluated when designing the study for which it is proposed. We demonstrate by example how simulation can be used to investigate whether minimization improves treatment balance compared with stratified randomization, and how much randomness can be incorporated into the minimization before any balance advantage is no longer retained. We also illustrate by example how the performance of the traditional model-based analysis can be assessed, by comparing the nominal test size with the observed test size over a large number of simulations. We recommend that the assignment probability for the minimization be selected using such simulations. Copyright (c) 2008 John Wiley & Sons, Ltd.

The impact of traffic sign deficit on road traffic accidents in Nigeria.

PubMed

Ezeibe, Christian; Ilo, Chukwudi; Oguonu, Chika; Ali, Alphonsus; Abada, Ifeanyi; Ezeibe, Ezinwanne; Oguonu, Chukwunonso; Abada, Felicia; Izueke, Edwin; Agbo, Humphrey

2018-04-04

This study assesses the impact of traffic sign deficit on road traffic accidents in Nigeria. The participants were 720 commercial vehicle drivers. While simple random sampling was used to select 6 out of 137 federal highways, stratified random sampling was used to select six categories of commercial vehicle drivers. The study used qual-dominant mixed methods approach comprising key informant interviews; group interviews; field observation; policy appraisal and secondary literature on traffic signs. Result shows that the failure of government to provide and maintain traffic signs in order to guide road users through the numerous accident black spots on the highways is the major cause of road accidents in Nigeria. The study argues that provision and maintenance of traffic signs present opportunity to promoting safety on the highways and achieving the sustainable development goals.

Impact of Jos Crises on Pattern of Students/Teachers' Population in Schools and Its Implication on the Quality of Teaching and Peaceful Co-Existence in Nigeria

ERIC Educational Resources Information Center

Jacob, Sunday

2015-01-01

This study examined the pattern of students/teachers' population in schools as a result of the crises witnessed in Jos and its consequences on quality of teaching as well as peaceful living in Jos. Stratified simple random sampling technique was used to select the 18 schools that were used for this study. Questionnaire was used to collect…

First direct landscape-scale measurement of tropical rain forest Leaf Area Index, a key driver of global primary productivity

Treesearch

David B. Clark; Paulo C. Olivas; Steven F. Oberbauer; Deborah A. Clark; Michael G. Ryan

2008-01-01

Leaf Area Index (leaf area per unit ground area, LAI) is a key driver of forest productivity but has never previously been measured directly at the landscape scale in tropical rain forest (TRF). We used a modular tower and stratified random sampling to harvest all foliage from forest floor to canopy top in 55 vertical transects (4.6 m2) across 500 ha of old growth in...

Comparison of Self-Efficacy and Self-Regulation between the Students with School Refusal Behavior (SRB) and the Students without (SRB), and the Relationships of These Variables to Academic Performance

ERIC Educational Resources Information Center

Khanehkeshi, Ali; Ahmedi, Farahnaz Azizi Tas

2013-01-01

The purpose of this study was to compare self-efficacy and self-regulation between the students with SRB and students with NSRB, and the relationship of these variables to academic performance. Using a random stratified sampling technique 60 girl students who had school refusal behavior (SRB) and 60 of students without SRB were selected from 8…

Uranium and other natural radionuclides in drinking water and risk of leukemia: a case-cohort study in Finland.

PubMed

Auvinen, Anssi; Kurttio, Päivi; Pekkanen, Juha; Pukkala, Eero; Ilus, Taina; Salonen, Laina

2002-11-01

We assessed the effect of natural uranium and other radionuclides in drinking water on risk of leukemia. The subjects (n = 144,627) in the base cohort had lived outside the municipal tapwater system during 1967-1980. A subcohort was formed as a stratified random sample of the base cohort and subjects using drinking water from drilled wells prior to 1981 were identified. A case-cohort design was used comparing exposure among cases with leukemia (n = 35) with a stratified random sample (n = 274) from the subcohort. Activity concentrations of uranium, radium-226, and radon in the drinking water were analyzed using radiochemical and alpha-spectrometric methods. The median activity concentration of uranium in well water was 0.08 Bq/L for the leukemia cases and 0.06 Bq/L for the reference group, radon concentrations 80 and 130 Bq/L, respectively, and radium-226 concentrations 0.01 Bq/L for both groups. The hazard ratio of leukemia for uranium was 0.91 (95% confidence interval 0.73-1.13) per Bq/L. for radon 0.79 per Bq/L (95% CI 0.27-2.29), and for radium-226 0.80 (95% CI 0.46-1.39) per Bq/L. Our results do not indicate an increased risk of leukemia from ingestion of natural uranium or other radionuclides through drinking water at these exposure levels.

Hyperspectral analysis of clay minerals

NASA Astrophysics Data System (ADS)

Janaki Rama Suresh, G.; Sreenivas, K.; Sivasamy, R.

2014-11-01

A study was carried out by collecting soil samples from parts of Gwalior and Shivpuri district, Madhya Pradesh in order to assess the dominant clay mineral of these soils using hyperspectral data, as 0.4 to 2.5 μm spectral range provides abundant and unique information about many important earth-surface minerals. Understanding the spectral response along with the soil chemical properties can provide important clues for retrieval of mineralogical soil properties. The soil samples were collected based on stratified random sampling approach and dominant clay minerals were identified through XRD analysis. The absorption feature parameters like depth, width, area and asymmetry of the absorption peaks were derived from spectral profile of soil samples through DISPEC tool. The derived absorption feature parameters were used as inputs for modelling the dominant soil clay mineral present in the unknown samples using Random forest approach which resulted in kappa accuracy of 0.795. Besides, an attempt was made to classify the Hyperion data using Spectral Angle Mapper (SAM) algorithm with an overall accuracy of 68.43 %. Results showed that kaolinite was the dominant mineral present in the soils followed by montmorillonite in the study area.

The systematic component of phylogenetic error as a function of taxonomic sampling under parsimony.

PubMed

Debry, Ronald W

2005-06-01

The effect of taxonomic sampling on phylogenetic accuracy under parsimony is examined by simulating nucleotide sequence evolution. Random error is minimized by using very large numbers of simulated characters. This allows estimation of the consistency behavior of parsimony, even for trees with up to 100 taxa. Data were simulated on 8 distinct 100-taxon model trees and analyzed as stratified subsets containing either 25 or 50 taxa, in addition to the full 100-taxon data set. Overall accuracy decreased in a majority of cases when taxa were added. However, the magnitude of change in the cases in which accuracy increased was larger than the magnitude of change in the cases in which accuracy decreased, so, on average, overall accuracy increased as more taxa were included. A stratified sampling scheme was used to assess accuracy for an initial subsample of 25 taxa. The 25-taxon analyses were compared to 50- and 100-taxon analyses that were pruned to include only the original 25 taxa. On average, accuracy for the 25 taxa was improved by taxon addition, but there was considerable variation in the degree of improvement among the model trees and across different rates of substitution.

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.

Use of health insurance claim patterns to identify patients using nonsteroidal anti-inflammatory drugs for rheumatoid arthritis.

PubMed

Bernard, Marie-Agnès; Bénichou, Jacques; Blin, Patrick; Weill, Alain; Bégaud, Bernard; Abouelfath, Abdelilah; Moore, Nicholas; Fourrier-Réglat, Annie

2012-06-01

To determine healthcare claim patterns associated using nonsteroidal anti-inflammatory drugs (NSAIDs) for rheumatoid arthritis (RA). The CADEUS study randomly identified NSAID users within the French health insurance database. One-year claims data were extracted, and NSAID indication was obtained from prescribers. Logistic regression was used in a development sample to identify claim patterns predictive of RA and models applied to a validation sample. Analyses were stratified on the dispensation of immunosuppressive agents or specific antirheumatism treatment, and the area under the receiver operating characteristic curve was used to estimate discriminant power. NSAID indication was provided for 26,259 of the 45,217 patients included in the CADEUS cohort; it was RA for 956 patients. Two models were constructed using the development sample (n = 13,143), stratifying on the dispensation of an immunosuppressive agent or specific antirheumatism treatment. Discriminant power was high for both models (AUC > 0.80) and was not statistically different from that found when applied to the validation sample (n = 13,116). The models derived from this study may help to identify patients prescribed NSAIDs who are likely to have RA in claims databases without medical data such as treatment indication. Copyright © 2012 John Wiley & Sons, Ltd.

Factors associated with successful functioning in American Indian youths.

PubMed

Silmere, Hiie; Stiffman, Arlene Rubin

2006-01-01

This study examines environmental and cultural factors related to successful functioning in a stratified random sample of 401 American Indian youths. The success index included seven indicators: good mental health, being alcohol- and drug-free, absence of serious misbehavior, clean police record, good grades, positive psychosocial functioning, and positive behavior and emotions. Family satisfaction was positively related to overall successful functioning, whereas misbehaving peers, living in a dysfunctional neighborhood, and experiencing child abuse had an inverse relationship with success.

Properties of the endogenous post-stratified estimator using a random forests model

Treesearch

John Tipton; Jean Opsomer; Gretchen G. Moisen

2012-01-01

Post-stratification is used in survey statistics as a method to improve variance estimates. In traditional post-stratification methods, the variable on which the data is being stratified must be known at the population level. In many cases this is not possible, but it is possible to use a model to predict values using covariates, and then stratify on these predicted...

Risk-Stratified Imputation in Survival Analysis

PubMed Central

Kennedy, Richard E.; Adragni, Kofi P.; Tiwari, Hemant K.; Voeks, Jenifer H.; Brott, Thomas G.; Howard, George

2013-01-01

Background Censoring that is dependent on covariates associated with survival can arise in randomized trials due to changes in recruitment and eligibility criteria to minimize withdrawals, potentially leading to biased treatment effect estimates. Imputation approaches have been proposed to address censoring in survival analysis; and while these approaches may provide unbiased estimates of treatment effects, imputation of a large number of outcomes may over- or underestimate the associated variance based on the imputation pool selected. Purpose We propose an improved method, risk-stratified imputation, as an alternative to address withdrawal related to the risk of events in the context of time-to-event analyses. Methods Our algorithm performs imputation from a pool of replacement subjects with similar values of both treatment and covariate(s) of interest, that is, from a risk-stratified sample. This stratification prior to imputation addresses the requirement of time-to-event analysis that censored observations are representative of all other observations in the risk group with similar exposure variables. We compared our risk-stratified imputation to case deletion and bootstrap imputation in a simulated dataset in which the covariate of interest (study withdrawal) was related to treatment. A motivating example from a recent clinical trial is also presented to demonstrate the utility of our method. Results In our simulations, risk-stratified imputation gives estimates of treatment effect comparable to bootstrap and auxiliary variable imputation while avoiding inaccuracies of the latter two in estimating the associated variance. Similar results were obtained in analysis of clinical trial data. Limitations Risk-stratified imputation has little advantage over other imputation methods when covariates of interest are not related to treatment, although its performance is superior when covariates are related to treatment. Risk-stratified imputation is intended for categorical covariates, and may be sensitive to the width of the matching window if continuous covariates are used. Conclusions The use of the risk-stratified imputation should facilitate the analysis of many clinical trials, in which one group has a higher withdrawal rate that is related to treatment. PMID:23818434

[Design of the National Surveillance of Nutritional Indicators (MONIN), Peru 2007-2010].

PubMed

Campos-Sánchez, Miguel; Ricaldi-Sueldo, Rita; Miranda-Cuadros, Marianella

2011-06-01

To describe the design and methods of the national surveillance of nutritional indicators (MONIN) 2007-2010, carried out by INS/CENAN. MONIN was designed as a continuous (repeated cross-sectional) survey, with stratified multi-stage random sampling, considering the universe as all under five children and pregnant women residing in Peru, divided into 5 geographical strata and 6 trimesters (randomly permuted weeks, about 78% of the time between November 19, 2007 and April 2, 2010). The total sample was 3,827 children in 361 completed clusters. The dropout rate was 8.4% in clusters, 1.8% in houses, and 13.2% in households. Dropout was also 4.2, 13.3, 21.2, 55% and 29% in anthropometry, hemoglobin, food intake, retinol and ioduria measurements, respectively. The MONIN design is feasible and useful for the estimation of indicators of childhood malnutrition.

An employee total health management-based survey of Iowa employers.

PubMed

Merchant, James A; Lind, David P; Kelly, Kevin M; Hall, Jennifer L

2013-12-01

To implement an Employee Total Health Management (ETHM) model-based questionnaire and provide estimates of model program elements among a statewide sample of Iowa employers. Survey a stratified random sample of Iowa employers, and characterize and estimate employer participation in ETHM program elements. Iowa employers are implementing less than 30% of all 12 components of ETHM, with the exception of occupational safety and health (46.6%) and workers' compensation insurance coverage (89.2%), but intend modest expansion of all components in the coming year. The ETHM questionnaire-based survey provides estimates of progress Iowa employers are making toward implementing components of Total Worker Health programs.

Comparison of sampling designs for estimating deforestation from landsat TM and MODIS imagery: a case study in Mato Grosso, Brazil.

PubMed

Zhu, Shanyou; Zhang, Hailong; Liu, Ronggao; Cao, Yun; Zhang, Guixin

2014-01-01

Sampling designs are commonly used to estimate deforestation over large areas, but comparisons between different sampling strategies are required. Using PRODES deforestation data as a reference, deforestation in the state of Mato Grosso in Brazil from 2005 to 2006 is evaluated using Landsat imagery and a nearly synchronous MODIS dataset. The MODIS-derived deforestation is used to assist in sampling and extrapolation. Three sampling designs are compared according to the estimated deforestation of the entire study area based on simple extrapolation and linear regression models. The results show that stratified sampling for strata construction and sample allocation using the MODIS-derived deforestation hotspots provided more precise estimations than simple random and systematic sampling. Moreover, the relationship between the MODIS-derived and TM-derived deforestation provides a precise estimate of the total deforestation area as well as the distribution of deforestation in each block.

Comparison of Sampling Designs for Estimating Deforestation from Landsat TM and MODIS Imagery: A Case Study in Mato Grosso, Brazil

PubMed Central

Zhu, Shanyou; Zhang, Hailong; Liu, Ronggao; Cao, Yun; Zhang, Guixin

2014-01-01

Sampling designs are commonly used to estimate deforestation over large areas, but comparisons between different sampling strategies are required. Using PRODES deforestation data as a reference, deforestation in the state of Mato Grosso in Brazil from 2005 to 2006 is evaluated using Landsat imagery and a nearly synchronous MODIS dataset. The MODIS-derived deforestation is used to assist in sampling and extrapolation. Three sampling designs are compared according to the estimated deforestation of the entire study area based on simple extrapolation and linear regression models. The results show that stratified sampling for strata construction and sample allocation using the MODIS-derived deforestation hotspots provided more precise estimations than simple random and systematic sampling. Moreover, the relationship between the MODIS-derived and TM-derived deforestation provides a precise estimate of the total deforestation area as well as the distribution of deforestation in each block. PMID:25258742

Differentials in colostrum feeding among lactating women of block RS Pura of J and K: A lesson for nursing practice.

PubMed

Raina, Sunil Kumar; Mengi, Vijay; Singh, Gurdeep

2012-07-01

Breast feeding is universally and traditionally practicised in India. Experts advocate breast feeding as the best method of feeding young infants. To assess the role of various factors in determining colostrum feeding in block R. S. Pura of district Jammu. A stratified two-stage design with villages as the primary sampling unit and lactating mothers as secondary sampling unit. Villages were divided into different clusters on the basis of population and sampling units were selected by a simple random technique. Breastfeeding is almost universal in R. S. Pura. Differentials in discarding the first milk were not found to be important among various socioeconomic groups and the phenomenon appeared more general than specific.

[Compliance with process indicators in people with type 2 diabetes and linking incentives in Primary Care].

PubMed

Pascual de la Pisa, Beatriz; Márquez Calzada, Cristina; Cuberos Sánchez, Carla; Cruces Jiménez, José Miguel; Fernández Gamaza, Manuel; Martínez Martínez, María Isabel

2015-03-01

Pay-for-performance programs to improve the quality of health care are extending gradually, particularly en Primary Health Care. Our aim was to explore the relationship between the degree of compliance with the process indicators (PrI) of type 2 diabetes (T2DM) in Primary Care and linkage to incentives. Cross-sectional, descriptive, observational study. Six Primary Health Care centers in Seville Aljarafe District randomly selected and stratified by population size. From 3.647 adults included in Integrated Healthcare Process of T2DM during 2008, 366 patients were included according sample size calculation by stratified random sampling. PrI: eye and feet examination, glycated hemoglobin, lipid profile, microalbuminuria and electrocardiogram. Confounding: Age, gender, characteristics town for patients and professional variables. The mean age was 66.36 years (standard deviation [DE]: 11,56); 48.9% were women. PrI with better compliance were feet examination, glycated hemoglobin and lipid profile (59.6%, 44.3% and 44%, respectively). 2.7% of patients had simultaneous compliance of the six PrI and 11.74% of patients three PrI linkage to incentives. Statistical association was observed in the compliance of the PrI incentives linked or not (P=.001). The degree of compliance with the PrI for screening chronic complications of T2DM is mostly low but this was higher on indicators linked to incentives. Copyright © 2013 Elsevier España, S.L.U. All rights reserved.

Prevalence of Listeria monocytogenes in Idiazabal cheese.

PubMed

Arrese, E; Arroyo-Izaga, M

2012-01-01

Raw-milk cheese has been identified in risk assessment as a food of greater concern to public health due to listeriosis. To determine the prevalence and levels of Listeria monocytogenes in semi-hard Idiazabal cheese manufactured by different producers in the Basque Country at consumer level. A total of 51 Idiazabal cheese samples were obtained from 10 separate retail establishments, chosen by stratified random sampling. Samples were tested using the official standard ISO procedure 11290-1 for detection and enumeration methods. All cheese samples tested negative for L. monocytogenes. However, 9.8% tested positive for Listeria spp., different from L. monocytogenes. Positive samples came from two brands, two were natural and three were smoked. The presence of Listeria spss. suggests that the cheese making process and the hygiene whether at milking or during cheese making could be insufficient.

Prevalence of drug use among drivers based on mandatory, random tests in a roadside survey

PubMed Central

Alcañiz, Manuela; Guillen, Montserrat

2018-01-01

Background In the context of road safety, this study aims to examine the prevalence of drug use in a random sample of drivers. Methods A stratified probabilistic sample was designed to represent vehicles circulating on non-urban roads. Random drug tests were performed during autumn 2014 on 521 drivers in Catalonia (Spain). Participation was mandatory. The prevalence of drug driving for cannabis, methamphetamines, amphetamines, cocaine, opiates and benzodiazepines was assessed. Results The overall prevalence of drug use is 16.4% (95% CI: 13.9; 18.9) and affects primarily younger male drivers. Drug use is similarly prevalent during weekdays and on weekends, but increases with the number of occupants. The likelihood of being positive for methamphetamines is significantly higher for drivers of vans and lorries. Conclusions Different patterns of use are detected depending on the drug considered. Preventive drug tests should not only be conducted on weekends and at night-time, and need to be reinforced for drivers of commercial vehicles. Active educational campaigns should focus on the youngest age-group of male drivers. PMID:29920542

Number of pins in two-stage stratified sampling for estimating herbage yield

Treesearch

William G. O' Regan; C. Eugene Conrad

1975-01-01

In a two-stage stratified procedure for sampling herbage yield, plots are stratified by a pin frame in stage one, and clipped. In stage two, clippings from selected plots are sorted, dried, and weighed. Sample size and distribution of plots between the two stages are determined by equations. A way to compute the effect of number of pins on the variance of estimated...

Effect of low-level laser therapy (LLLT) and light-emitting diodes (LEDT) applied during combined training on performance and post-exercise recovery: protocol for a randomized placebo-controlled trial.

PubMed

Machado, Aryane Flauzino; Micheletti, Jéssica Kirsch; Vanderlei, Franciele Marques; Nakamura, Fabio Yuzo; Leal-Junior, Ernesto Cesar Pinto; Netto Junior, Jayme; Pastre, Carlos Marcelo

Previous studies have shown positive results of phototherapy for improving performance and accelerating recovery; however, the effects of phototherapy during training and after a primary adaptation remain unclear. The aim of this randomized controlled trial is to analyze the effects of phototherapy and combined training on clinical, functional, and psychological outcomes and on vascular endothelial growth factor. This randomized placebo-controlled trial by stratified sample will involve 45 healthy male participants. In phase 1, the participants will undergo six weeks of combined training (sprints and squats). In phase 2, participants will be allocated through stratified randomization (based on adaptation capacity) into three groups: active phototherapy group (AG), placebo group (PG), and non-treatment control group (CG). A new six-week training program will then start and the participants will receive the recovery strategy between sprints and squats. The primary outcome will be maximal isometric contraction. The secondary outcomes include strength and power testing, maximal incremental test, squat jump, sprint test, muscle soreness, pain threshold, perceptions of exertion and recovery, psychological questionnaire, and vascular endothelial growth factor. This will be the first trial to include phototherapy during training. We believe that this strategy will combine the ergogenic and prophylactic effects in the same session. Furthermore, an application protocol performed after primary adaptation may reflect the real effect of the technique. Copyright © 2017 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

On the importance of incorporating sampling weights in ...

EPA Pesticide Factsheets

Occupancy models are used extensively to assess wildlife-habitat associations and to predict species distributions across large geographic regions. Occupancy models were developed as a tool to properly account for imperfect detection of a species. Current guidelines on survey design requirements for occupancy models focus on the number of sample units and the pattern of revisits to a sample unit within a season. We focus on the sampling design or how the sample units are selected in geographic space (e.g., stratified, simple random, unequal probability, etc). In a probability design, each sample unit has a sample weight which quantifies the number of sample units it represents in the finite (oftentimes areal) sampling frame. We demonstrate the importance of including sampling weights in occupancy model estimation when the design is not a simple random sample or equal probability design. We assume a finite areal sampling frame as proposed for a national bat monitoring program. We compare several unequal and equal probability designs and varying sampling intensity within a simulation study. We found the traditional single season occupancy model produced biased estimates of occupancy and lower confidence interval coverage rates compared to occupancy models that accounted for the sampling design. We also discuss how our findings inform the analyses proposed for the nascent North American Bat Monitoring Program and other collaborative synthesis efforts that propose h

Serological status of Canadian cattle for brucellosis, anaplasmosis, and bluetongue in 2007-2008.

PubMed

Paré, Julie; Geale, Dorothy W; Koller-Jones, Maria; Hooper-McGrevy, Kathleen; Golsteyn-Thomas, Elizabeth J; Power, Christine A

2012-09-01

A national bovine serological survey was conducted to confirm that the prevalence of brucellosis, bluetongue, and anaplasmosis does not exceed 0.02% (95% confidence) in live cattle in Canada. Sampling consisted of a systematic random sample of 15 482 adult cattle slaughtered in federally inspected abattoirs, stratified by province. Samples were tested to detect antibodies for brucellosis, bluetongue, and anaplasmosis. All samples were negative for brucellosis. Three samples were seroreactors to bluetongue, 2 of which originated from the Okanagan Valley in British Columbia and 1 from Ontario, which after follow-up, was considered an atypical result. A total of 244 samples were seroreactors to Anaplasma and follow-up identified infection in Saskatchewan, Manitoba, and Quebec. In conclusion, the Canadian cattle population remains free of brucellosis and free of bluetongue outside the Okanagan Valley. Canada is no longer free of anaplasmosis and will be unable to claim freedom until eradication measures are completed.

Evaluation of a health promotion program in children: Study protocol and design of the cluster-randomized Baden-Württemberg primary school study [DRKS-ID: DRKS00000494

PubMed Central

2012-01-01

Background Increasing prevalences of overweight and obesity in children are known problems in industrialized countries. Early prevention is important as overweight and obesity persist over time and are related with health problems later in adulthood. "Komm mit in das gesunde Boot - Grundschule" is a school-based program to promote a healthier lifestyle. Main goals of the intervention are to increase physical activity, decrease the consumption of sugar-sweetened beverages, and to decrease time spent sedentary by promoting active choices for healthy lifestyle. The program to date is distributed by 34 project delivery consultants in the state of Baden-Württemberg and is currently implemented in 427 primary schools. The efficacy of this large scale intervention is examined via the Baden-Württemberg Study. Methods/Design The Baden-Württemberg Study is a prospective, stratified, cluster-randomized, and longitudinal study with two groups (intervention group and control group). Measurements were taken at the beginning of the academic years 2010/2011 and 2011/2012. Efficacy of the intervention is being assessed using three main outcomes: changes in waist circumference, skinfold thickness and 6 minutes run. Stratified cluster-randomization (according to class grade level) was performed for primary schools; pupils, teachers/principals, and parents were investigated. An approximately balanced number of classes in intervention group and control group could be reached by stratified randomization and was maintained at follow-up. Discussion At present, "Komm mit in das Gesunde Boot - Grundschule" is the largest school-based health promotion program in Germany. Comparative objective main outcomes are used for the evaluation of efficacy. Simulations showed sufficient power with the existing sample size. Therefore, the results will show whether the promotion of a healthier lifestyle in primary school children is possible using a relatively low effort within a school-based program involving children, teachers and parents. The research team anticipates that not only efficacy will be proven in this study but also expects many other positive effects of the program. Trial registration German Clinical Trials Register (DRKS), DRKS-ID: DRKS00000494 PMID:22394693

Evaluation of a health promotion program in children: Study protocol and design of the cluster-randomized Baden-Württemberg primary school study [DRKS-ID: DRKS00000494].

PubMed

Dreyhaupt, Jens; Koch, Benjamin; Wirt, Tamara; Schreiber, Anja; Brandstetter, Susanne; Kesztyüs, Dorothea; Wartha, Olivia; Kobel, Susanne; Kettner, Sarah; Prokopchuk, Dmytro; Hundsdörfer, Verena; Klepsch, Melina; Wiedom, Martina; Sufeida, Sabrina; Fischbach, Nanette; Muche, Rainer; Seufert, Tina; Steinacker, Jürgen Michael

2012-03-06

Increasing prevalences of overweight and obesity in children are known problems in industrialized countries. Early prevention is important as overweight and obesity persist over time and are related with health problems later in adulthood. "Komm mit in das gesunde Boot - Grundschule" is a school-based program to promote a healthier lifestyle. Main goals of the intervention are to increase physical activity, decrease the consumption of sugar-sweetened beverages, and to decrease time spent sedentary by promoting active choices for healthy lifestyle. The program to date is distributed by 34 project delivery consultants in the state of Baden-Württemberg and is currently implemented in 427 primary schools. The efficacy of this large scale intervention is examined via the Baden-Württemberg Study. The Baden-Württemberg Study is a prospective, stratified, cluster-randomized, and longitudinal study with two groups (intervention group and control group). Measurements were taken at the beginning of the academic years 2010/2011 and 2011/2012. Efficacy of the intervention is being assessed using three main outcomes: changes in waist circumference, skinfold thickness and 6 minutes run. Stratified cluster-randomization (according to class grade level) was performed for primary schools; pupils, teachers/principals, and parents were investigated. An approximately balanced number of classes in intervention group and control group could be reached by stratified randomization and was maintained at follow-up. At present, "Komm mit in das Gesunde Boot - Grundschule" is the largest school-based health promotion program in Germany. Comparative objective main outcomes are used for the evaluation of efficacy. Simulations showed sufficient power with the existing sample size. Therefore, the results will show whether the promotion of a healthier lifestyle in primary school children is possible using a relatively low effort within a school-based program involving children, teachers and parents. The research team anticipates that not only efficacy will be proven in this study but also expects many other positive effects of the program. German Clinical Trials Register (DRKS), DRKS-ID: DRKS00000494.

Age-specific seroprevalence of dengue infection in Hong Kong.

PubMed

Lee, Polly; Yeung, Apple C M; Chen, Zigui; Chan, Martin C W; Sze, Kin Ho; Chan, Paul K S

2018-05-02

A newly developed dengue virus vaccine (chimeric yellow fever virus-tetravalent dengue vaccine [CYD-TDV]) has recently been licensed for clinical use. The World Health Organization recommends vaccination for populations with seroprevalence of at least 70% to maximize public health impact. This study aimed to delineate the seroprevalence of dengue infection in Hong Kong. A total of 105 972 serum samples submitted for clinical testing during the period 2013-2015 were age-stratified and sex-stratified. For each year of collection, 25 samples were randomly selected from each age-sex group. Altogether, 2100 samples were tested for the dengue immunoglobulin G (IgG) antibody using a non-type-specific ELISA kit. The overall dengue IgG-positive rate was 4.6% and showed no significant change over the 3 years. The positive rate was not associated with sex, but a steep rise in seroprevalence for persons above 65 years (32.7%) was observed. The low dengue seroprevalence in Hong Kong does not support implementation of a national immunization program. Majority of the population in Hong Kong are susceptible to dengue infection, and a substantial proportion of persons older than 65 years could acquire secondary infection and are prone to develop severe dengue. © 2018 Wiley Periodicals, Inc.

An Employee Total Health Management–Based Survey of Iowa Employers

PubMed Central

Merchant, James A.; Lind, David P.; Kelly, Kevin M.; Hall, Jennifer L.

2015-01-01

Objective To implement an Employee Total Health Management (ETHM) model-based questionnaire and provide estimates of model program elements among a statewide sample of Iowa employers. Methods Survey a stratified random sample of Iowa employers, characterize and estimate employer participation in ETHM program elements Results Iowa employers are implementing under 30% of all 12 components of ETHM, with the exception of occupational safety and health (46.6%) and worker compensation insurance coverage (89.2%), but intend modest expansion of all components in the coming year. Conclusions The Employee Total Health Management questionnaire-based survey provides estimates of progress Iowa employers are making toward implementing components of total worker health programs. PMID:24284757

Teacher drug use: a response to occupational stress.

PubMed

Watts, W D; Short, A P

1990-01-01

Work-related stress is predicted to be correlated with wanting to leave the teaching profession and drug use. A stratified random sample of 500 Texas teachers was surveyed (56.5% responded), regarding working conditions, collegial and supervisory relationships, job satisfaction, rigidity of attitudes and drug use. Two-thirds of teachers may want to quit the profession, while 36.4 percent are likely to quit. Teachers report higher rates than a national sample of lifetime alcohol, amphetamine, and tranquilizer use and higher rates of alcohol use in the last year and last month. Selected measures of stress are correlated with drug use, particularly amphetamine use, over the lifetime, last year, and last month.

Exploitation: comparing sexual and violent imagery of females and males in advertising.

PubMed

Rudman, W J; Verdi, P

1993-01-01

This study examines the way female and male models are portrayed in magazine advertisements. Specifically, we focus on differences in sex role stereotyping, sexual display of the body, and violent imagery. Data were collected from a stratified random sample of magazines displaying fashion and fitness advertisements (N = 254). Findings from the analysis show that females are more likely than males to be placed in submissive positions, sexually displayed, and subjects of violent imagery. Sexual display and violent imagery measures are the strongest predictors of subjective level of exploitation.

Health status of hotel workers with special reference to high risk practices and STDs.

PubMed

Pawar, A T; Kakrani, V A

2007-01-01

A cross sectional study was conducted on health status of hotel workers of Pune city. Out of estimated 1000 hotel workers 516 were selected by stratified random sampling technique. The study revealed that 71.5% hotel workers were suffering from one or other type of morbid condition. Anemia was the commonest morbidity with prevalence of 40.3%. 187 (36.2%) of hotel workers had extramarital sexual relations. A total of 77 (14.9%) hotel workers were having STDs at the time of study.

Turkish adolescents' attitudes toward physical education.

PubMed

Hünük, Deniz; Demirhan, Giyasettin

2010-10-01

1,163 middle school students (586 girls, 577 boys; Grades 6-8) were selected through a stratified random sampling method to examine their attitudes toward physical education (PE) by grade, student's sex, sports participation characteristics, and teacher's sex. They were administered the Attitude Toward Physical Education Scale for Children. Factorial analysis of variance indicated that Grade 8 students' mean attitude scores were less positive than those of Grade 6 students, but the attitudes of boys and of sports participants were more positive than of girls and nonsports participants. Findings were similar regardless of the teacher's sex.

Social image of students who shop and don't shop online.

PubMed

Lammers, H Bruce; Curren, Mary T; Cours, Deborah; Lammers, Marilyn L

2003-06-01

A descriptive survey of a stratified random sample of 326 undergraduates from a large, diverse university in Los Angeles was conducted to assess whether resistance to online shopping might be, in part, related to negative social perceptions of those who shop online. Indirect questioning showed that students perceived online student shoppers as more lazy and less likely to fear for the safety and security of others but also as more trustworthy, attractive, successful, and smart. Differences in social perceptions were not related to these students' own online spending.

Designing a national soil erosion monitoring network for England and Wales

NASA Astrophysics Data System (ADS)

Lark, Murray; Rawlins, Barry; Anderson, Karen; Evans, Martin; Farrow, Luke; Glendell, Miriam; James, Mike; Rickson, Jane; Quine, Timothy; Quinton, John; Brazier, Richard

2014-05-01

Although soil erosion is recognised as a significant threat to sustainable land use and may be a priority for action in any forthcoming EU Soil Framework Directive, those responsible for setting national policy with respect to erosion are constrained by a lack of robust, representative, data at large spatial scales. This reflects the process-orientated nature of much soil erosion research. Recognising this limitation, The UK Department for Environment, Food and Rural Affairs (Defra) established a project to pilot a cost-effective framework for monitoring of soil erosion in England and Wales (E&W). The pilot will compare different soil erosion monitoring methods at a site scale and provide statistical information for the final design of the full national monitoring network that will: provide unbiased estimates of the spatial mean of soil erosion rate across E&W (tonnes ha-1 yr-1) for each of three land-use classes - arable and horticultural grassland upland and semi-natural habitats quantify the uncertainty of these estimates with confidence intervals. Probability (design-based) sampling provides most efficient unbiased estimates of spatial means. In this study, a 16 hectare area (a square of 400 x 400 m) positioned at the centre of a 1-km grid cell, selected at random from mapped land use across E&W, provided the sampling support for measurement of erosion rates, with at least 94% of the support area corresponding to the target land use classes. Very small or zero erosion rates likely to be encountered at many sites reduce the sampling efficiency and make it difficult to compare different methods of soil erosion monitoring. Therefore, to increase the proportion of samples with larger erosion rates without biasing our estimates, we increased the inclusion probability density in areas where the erosion rate is likely to be large by using stratified random sampling. First, each sampling domain (land use class in E&W) was divided into strata; e.g. two sub-domains within which, respectively, small or no erosion rates, and moderate or larger erosion rates are expected. Each stratum was then sampled independently and at random. The sample density need not be equal in the two strata, but is known and is accounted for in the estimation of the mean and its standard error. To divide the domains into strata we used information on slope angle, previous interpretation of erosion susceptibility of the soil associations that correspond to the soil map of E&W at 1:250 000 (Soil Survey of England and Wales, 1983), and visual interpretation of evidence of erosion from aerial photography. While each domain could be stratified on the basis of the first two criteria, air photo interpretation across the whole country was not feasible. For this reason we used a two-phase random sampling for stratification (TPRS) design (de Gruijter et al., 2006). First, we formed an initial random sample of 1-km grid cells from the target domain. Second, each cell was then allocated to a stratum on the basis of the three criteria. A subset of the selected cells from each stratum were then selected for field survey at random, with a specified sampling density for each stratum so as to increase the proportion of cells where moderate or larger erosion rates were expected. Once measurements of erosion have been made, an estimate of the spatial mean of the erosion rate over the target domain, its standard error and associated uncertainty can be calculated by an expression which accounts for the estimated proportions of the two strata within the initial random sample. de Gruijter, J.J., Brus, D.J., Biekens, M.F.P. & Knotters, M. 2006. Sampling for Natural Resource Monitoring. Springer, Berlin. Soil Survey of England and Wales. 1983 National Soil Map NATMAP Vector 1:250,000. National Soil Research Institute, Cranfield University.

Determination of reference values for elevated fasting and random insulin levels and their associations with metabolic risk factors among rural Pakistanis from Sindh Province.

PubMed

Ahmadani, Muhammad Yakoob; Hakeem, Rubina; Fawwad, Asher; Basit, Abdul; Shera, A Samad

2008-06-01

To assess insulin levels and their association with metabolic risk factors (family history of diabetes, abnormal glucose tolerance, hypertension, overweight and android obesity) among a representative group of Pakistan. The study data was taken from the database of a population-based survey conducted in Sindh Province, Pakistan, in 1994 to assess the prevalence of diabetes mellitus and impaired glucose tolerance (IGT). Through stratified random sampling; oral glucose tolerance tests were performed in 967 adults; every fifth sample was estimated for fasting and random (2-hour post-75 gm glucose load) insulin levels. The total number of metabolic risk factors was counted for each subject, and their association with insulin levels studied. Of the 130 subjects, 56.1% were females and 95.4% were Sindhi. The mean age of males and females was 43.84 and 40.61 years, respectively. Family history for diabetes and frequency of overweight had significant positive associations with both fasting and random insulin levels (P < 0.05). Association between hypertension and insulin levels was significant only for random insulin levels, and between android obesity, abnormal glucose tolerance, or male gender and insulin levels only for fasting insulin levels (P < 0.05). Metabolic risk factors had significant positive associations with both fasting (r = 0.351 P = 0.000) as well as random insulin levels (r = 0.364 P = 0.000). This paper provides baseline pioneering information applicable to the Pakistani population. Furthermore, the observations made in this study about differences in association of fasting or random insulin levels with various metabolic risk factors highlight the possibility of using either of them for risk assessment. This finding needs to be assessed in a larger and nationally representative sample.

Reasons for nonresponse in a web-based survey of alcohol involvement among first-year college students.

PubMed

Cranford, James A; McCabe, Sean Esteban; Boyd, Carol J; Slayden, Janie; Reed, Mark B; Ketchie, Julie M; Lange, James E; Scott, Marcia S

2008-01-01

This study conducted a follow-up telephone survey of a probability sample of college students who did not respond to a Web survey to determine correlates of and reasons for nonresponse. A stratified random sample of 2502 full-time first-year undergraduate students was invited to participate in a Web-based survey. A random sample of 221 students who did not respond to the original Web survey completed an abbreviated version of the original survey by telephone. Nonresponse did not vary by gender, but nonresponse was higher among Blacks and Hispanics compared to Whites, and Blacks compared to Asians. Nonresponders reported lower frequency of past 28 days drinking, lower levels of past-year and past 28-days heavy episodic drinking, and more time spent preparing for classes than responders. The most common reasons for nonresponse were "too busy" (45.7%), "not interested" (18.1%), and "forgot to complete survey" (18.1%). Reasons for nonresponse to Web surveys among college students are similar to reasons for nonresponse to mail and telephone surveys, and some nonresponse reasons vary as a function of alcohol involvement.

[Growth and development of children in Cuba].

PubMed

Jordán Rodríguez, J; Bebel Agua, A; Rubén, M; Hernández, J

1980-01-01

During the years 1972 to 1974, a great scale study was carried out on development and growth taking at random a stratified sample of multiple stages of 50,311 children from birth to 20 years. Fifteen anthropometric dimensions were considered and evaluation was made of sexual development in both sexes. In girls, the age of menarche was registered. An X-ray of the hand was taken to 10% of the sample. One year later, 30% of the sample was X-rayed again to determine speed of growth. Response of the population was close to 94%. The importance of a national system of growth is recognized, together with the colaboration of the orgaism of masses to achieve these purposes. Information related with some of measurements reported is offered and comments related with these findings are made.

A stratified two-stage sampling design for digital soil mapping in a Mediterranean basin

NASA Astrophysics Data System (ADS)

Blaschek, Michael; Duttmann, Rainer

2015-04-01

The quality of environmental modelling results often depends on reliable soil information. In order to obtain soil data in an efficient manner, several sampling strategies are at hand depending on the level of prior knowledge and the overall objective of the planned survey. This study focuses on the collection of soil samples considering available continuous secondary information in an undulating, 16 km²-sized river catchment near Ussana in southern Sardinia (Italy). A design-based, stratified, two-stage sampling design has been applied aiming at the spatial prediction of soil property values at individual locations. The stratification based on quantiles from density functions of two land-surface parameters - topographic wetness index and potential incoming solar radiation - derived from a digital elevation model. Combined with four main geological units, the applied procedure led to 30 different classes in the given test site. Up to six polygons of each available class were selected randomly excluding those areas smaller than 1ha to avoid incorrect location of the points in the field. Further exclusion rules were applied before polygon selection masking out roads and buildings using a 20m buffer. The selection procedure was repeated ten times and the set of polygons with the best geographical spread were chosen. Finally, exact point locations were selected randomly from inside the chosen polygon features. A second selection based on the same stratification and following the same methodology (selecting one polygon instead of six) was made in order to create an appropriate validation set. Supplementary samples were obtained during a second survey focusing on polygons that have either not been considered during the first phase at all or were not adequately represented with respect to feature size. In total, both field campaigns produced an interpolation set of 156 samples and a validation set of 41 points. The selection of sample point locations has been done using ESRI software (ArcGIS) extended by Hawth's Tools and later on its replacement the Geospatial Modelling Environment (GME). 88% of all desired points could actually be reached in the field and have been successfully sampled. Our results indicate that the sampled calibration and validation sets are representative for each other and could be successfully used as interpolation data for spatial prediction purposes. With respect to soil textural fractions, for instance, equal multivariate means and variance homogeneity were found for the two datasets as evidenced by significant (P > 0.05) Hotelling T²-test (2.3 with df1 = 3, df2 = 193) and Bartlett's test statistics (6.4 with df = 6). The multivariate prediction of clay, silt and sand content using a neural network residual cokriging approach reached an explained variance level of 56%, 47% and 63%. Thus, the presented case study is a successful example of considering readily available continuous information on soil forming factors such as geology and relief as stratifying variables for designing sampling schemes in digital soil mapping projects.

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.

Some design issues of strata-matched non-randomized studies with survival outcomes.

PubMed

Mazumdar, Madhu; Tu, Donsheng; Zhou, Xi Kathy

2006-12-15

Non-randomized studies for the evaluation of a medical intervention are useful for quantitative hypothesis generation before the initiation of a randomized trial and also when randomized clinical trials are difficult to conduct. A strata-matched non-randomized design is often utilized where subjects treated by a test intervention are matched to a fixed number of subjects treated by a standard intervention within covariate based strata. In this paper, we consider the issue of sample size calculation for this design. Based on the asymptotic formula for the power of a stratified log-rank test, we derive a formula to calculate the minimum number of subjects in the test intervention group that is required to detect a given relative risk between the test and standard interventions. When this minimum number of subjects in the test intervention group is available, an equation is also derived to find the multiple that determines the number of subjects in the standard intervention group within each stratum. The methodology developed is applied to two illustrative examples in gastric cancer and sarcoma.

Field substitution of nonresponders can maintain sample size and structure without altering survey estimates-the experience of the Italian behavioral risk factors surveillance system (PASSI).

PubMed

Baldissera, Sandro; Ferrante, Gianluigi; Quarchioni, Elisa; Minardi, Valentina; Possenti, Valentina; Carrozzi, Giuliano; Masocco, Maria; Salmaso, Stefania

2014-04-01

Field substitution of nonrespondents can be used to maintain the planned sample size and structure in surveys but may introduce additional bias. Sample weighting is suggested as the preferable alternative; however, limited empirical evidence exists comparing the two methods. We wanted to assess the impact of substitution on surveillance results using data from Progressi delle Aziende Sanitarie per la Salute in Italia-Progress by Local Health Units towards a Healthier Italy (PASSI). PASSI is conducted by Local Health Units (LHUs) through telephone interviews of stratified random samples of residents. Nonrespondents are replaced with substitutes randomly preselected in the same LHU stratum. We compared the weighted estimates obtained in the original PASSI sample (used as a reference) and in the substitutes' sample. The differences were evaluated using a Wald test. In 2011, 50,697 units were selected: 37,252 were from the original sample and 13,445 were substitutes; 37,162 persons were interviewed. The initially planned size and demographic composition were restored. No significant differences in the estimates between the original and the substitutes' sample were found. In our experience, field substitution is an acceptable method for dealing with nonresponse, maintaining the characteristics of the original sample without affecting the results. This evidence can support appropriate decisions about planning and implementing a surveillance system. Copyright © 2014 Elsevier Inc. All rights reserved.

Impact of canine-assisted ambulation on hospitalized chronic heart failure patients' ambulation outcomes and satisfaction: a pilot study.

PubMed

Abate, Samantha V; Zucconi, Michele; Boxer, Bruce Alan

2011-01-01

Chronic heart failure (HF) is a prevalent and costly disease process. Early ambulation has been shown to have a positive impact on patient outcomes and length of stay. Animal-assisted therapy is a novel modality that has shown to be a safe and effective adjunct to a number of traditional treatment plans. This study sought to synergistically combine ambulation and animal-assisted therapy by using canine-assisted ambulation (CAA) to improve the ambulation outcomes of HF patients. Sixty-nine hospitalized patients with a primary diagnosis of HF were approached to ambulate with a restorative aide. After recording their initial response, they were given the opportunity to participate in CAA (walking with a therapy dog). Initial ambulation refusal rate was compared with a historical population of 537 HF patients. Distance ambulated was recorded using a pedometer and compared with a randomly selected, 64-patient sample from the historical HF patient population, stratified by day of hospital stay. Patient satisfaction was assessed through a 5-item Likert scale survey. The 537-patient historical HF population had an ambulation refusal rate of 28%. When offered the chance to participate in CAA, only 7.2% of the study population refused ambulation (P = .0002). Of the 69-patient study sample, 13 initially refused ambulation then agreed when offered CAA (P = .0009). Distance ambulated increased from 120.2 steps in a randomly selected, stratified historical sample to 235.07 in the CAA study sample (P < .0001). Patients unanimously agreed that they enjoyed CAA and would like to participate in CAA again. Canine-assisted ambulation is a safe and effective adjunct to an early ambulation program for HF patients. Canine-assisted ambulation may decrease hospital length of stay and thereby decrease the costs of HF care. Additional research involving CAA's application to other disease processes in various settings is warranted.

Seroprevalence and some correlates of Helicobacter pylori at adult ages in Gülveren Health District, Ankara, Turkey.

PubMed Central

Akin, L.; Tezcan, S.; Hascelik, G.; Cakir, B.

2004-01-01

The purpose of the study was to detect the frequency and distribution of Helicobacter pylori in the Gülveren Health Centre service area among residents aged between 25 and 64 years and to evaluate the relation of H. pylori infections with general health status, socioeconomic status, and some lifestyle habits. The study included a representative sample of Gülveren Health Centre residents, aged between 25 and 64 years. A stratified random sample of 1672 individuals was selected for study purposes out of 10,569 residents, stratified by age and gender. A standardized questionnaire was completed for all study participants using a face-to-face interview and all participants were invited to the local health centre for a thorough physical examination and blood tests. The overall prevalence of H. pylori was found to be 77.5 % among individuals aged between 25 and 64 years. The frequency of H. pylori was higher among individuals with low socioeconomic status; those who migrated to Ankara after the age of 20 years; members of large families (household size of 4 or above); non-alcohol drinkers; and those who regularly drink tea. PMID:15473147

Visitor and community survey results for Prime Hook National Wildlife Refuge: Completion report

USGS Publications Warehouse

Sexton, Natalie R.; Stewart, Susan C.; Koontz, Lynne; Ponds, Phadrea; Walters, Katherine D.

2007-01-01

Community residents’ perceptions and opinions Data for this study were collected using a survey administered to visitors to Prime Hook NWR and individuals living in the communities surrounding the Refuge. Surveys were randomly distributed to both consumptive and nonconsumptive use visitors over a one year period (September 2004 to September 2005) to account for seasonal variation in Refuge use. Three hundred thirty-two visitor surveys were returned for a response rate of 80 percent with a confidence interval of ± 5.4. Surveys were also distributed to a stratified random sample of community members in adjacent and surrounding areas (Slaughter Beach, Broadkill Beach, Prime Hook Beach, Milton, Lewes, Milford, and surrounding communities). Four hundred ninety-one surveys from the overall community sample were returned for a response rate of 39 percent with a ± 4.4 confidence interval. Community member results were weighted by U.S. Census Bureau data to correct for age and gender bias, and for community proportionality.

Factual knowledge about AIDS and dating practices among high school students from selected schools.

PubMed

Nyachuru-Sihlangu, R H; Ndlovu, J

1992-06-01

Following various educational strategies by governmental and non-governmental organisations to educate youths and school teachers about HIV infection and prevention, this KABP survey was one attempt to evaluate the results. The study sample of 478 high school students was drawn from four randomly selected schools in Mashonaland and Matabeleland including high and low density, government and mission co-educational schools. The sample was randomly selected and stratified to represent sex and grade level. The KABP self administered questionnaire was used. The paper analyses the relationship between the knowledge and dating patterns. Generally, respondents demonstrated a 50pc to 80pc accuracy of factual knowledge. Of the 66pc Forms I through IV pupils who dated, 30pc preferred only sexually involved relationships and a small number considered the possibility of HIV/AIDS infection. A theoretically based tripartite coalition involving the school, the family health care services for education, guidance and support to promote responsible behaviour throughout childhood was suggested.

Vitamin A deficiency and xerophthalmia in western Yemen.

PubMed

Rosen, D S; al Sharif, Z; Bashir, M; al Shabooti, A; Pizzarello, L D

1996-01-01

To determine the prevalence of xerophthalmia and the extent of vitamin A deficiency in western Yemen. A stratified cluster sample of children aged 1-5 years with clinical examination for signs of xerophthalmia as well as blood serum survey. The 18 districts of western Yemen, of which 10 clusters were chosen at random. All children aged 1-5 years resident in the cluster sites (n = 2438). Clinical signs of xerophthalmia, a history of night blindness, serum retinol levels in a random sample of clinically normal children (n =338) in addition to all children with xerophthalmia. Night blindness was found in 0.5% of the children, Bitot's spots in 1.7%, corneal ulceration in 0.04% and corneal scars in 0.04% Of the subsample, 7.2% (95% confidence interval [c.i.] 4.4-10.0%) had serum retinol values below 10 micrograms/dl; 63.0% (95% c.i. 57.6- 68.4%) had values below 20 micrograms/dl. Xerophthalmia and vitamin A deficiency are public health problems in western Yemen.

A critical thinking disposition scale for nurses: short form.

PubMed

Hwang, Shiow-Y; Yen, Miaofen; Lee, Bih-O; Huang, Mei-C; Tseng, Hung-F

2010-11-01

The aim of this study was to test the Chinese version of the Critical Thinking Disposition Inventory (CTDI-CV) among nurses in Taiwan. Critical thinking is the use of purposeful self-regulatory judgments to identify patient's problems and provide patient care. Critical thinking influences nurses' decision making. To date, no inventory to understand nurse's critical thinking disposition has been developed. This was a survey design with a stratified random sampling to test the reliability and validity of the CTDI-CV. The participants comprised 864 registered nurses who were chosen by stratified random sampling from seven hospitals in Taiwan. Data were collected through self-administered structured questionnaires. A new scale, short form (SF) CTDI-CV, contains 18 items with three subscales: 'systematic analysis', 'thinking within the box' and 'thinking out of the box', was generated from the analysis with 44% explained variance. Cronbach's alpha coefficients and intra-class correlation coefficients for overall and subscale were above 0.8. Goodness-of-fit test for the final model of SF-CTDI-CV revealed an acceptable result in the overall fit (χ(2)/df = 4.04, p < 0.05, GFI = 0.93, AGFI = 0.91, SRMR = 0.076, RMSEA = 0.059). On the basis of these results, the SF-CTDI-CV is a reliable instrument for assessing critical thinking disposition for nurses. A short and valid critical thinking instrument for nurses will facilitate critical thinking research in the clinical practice arena. When designing continuing education activities, clinical educators will be able to efficiently and effectively evaluate the quality of critical thinking among practicing nurses. © 2010 Blackwell Publishing Ltd.

A tale of two "forests": random forest machine learning AIDS tropical forest carbon mapping.

PubMed

Mascaro, Joseph; Asner, Gregory P; Knapp, David E; Kennedy-Bowdoin, Ty; Martin, Roberta E; Anderson, Christopher; Higgins, Mark; Chadwick, K Dana

2014-01-01

Accurate and spatially-explicit maps of tropical forest carbon stocks are needed to implement carbon offset mechanisms such as REDD+ (Reduced Deforestation and Degradation Plus). The Random Forest machine learning algorithm may aid carbon mapping applications using remotely-sensed data. However, Random Forest has never been compared to traditional and potentially more reliable techniques such as regionally stratified sampling and upscaling, and it has rarely been employed with spatial data. Here, we evaluated the performance of Random Forest in upscaling airborne LiDAR (Light Detection and Ranging)-based carbon estimates compared to the stratification approach over a 16-million hectare focal area of the Western Amazon. We considered two runs of Random Forest, both with and without spatial contextual modeling by including--in the latter case--x, and y position directly in the model. In each case, we set aside 8 million hectares (i.e., half of the focal area) for validation; this rigorous test of Random Forest went above and beyond the internal validation normally compiled by the algorithm (i.e., called "out-of-bag"), which proved insufficient for this spatial application. In this heterogeneous region of Northern Peru, the model with spatial context was the best preforming run of Random Forest, and explained 59% of LiDAR-based carbon estimates within the validation area, compared to 37% for stratification or 43% by Random Forest without spatial context. With the 60% improvement in explained variation, RMSE against validation LiDAR samples improved from 33 to 26 Mg C ha(-1) when using Random Forest with spatial context. Our results suggest that spatial context should be considered when using Random Forest, and that doing so may result in substantially improved carbon stock modeling for purposes of climate change mitigation.

A Tale of Two “Forests”: Random Forest Machine Learning Aids Tropical Forest Carbon Mapping

PubMed Central

Mascaro, Joseph; Asner, Gregory P.; Knapp, David E.; Kennedy-Bowdoin, Ty; Martin, Roberta E.; Anderson, Christopher; Higgins, Mark; Chadwick, K. Dana

2014-01-01

Accurate and spatially-explicit maps of tropical forest carbon stocks are needed to implement carbon offset mechanisms such as REDD+ (Reduced Deforestation and Degradation Plus). The Random Forest machine learning algorithm may aid carbon mapping applications using remotely-sensed data. However, Random Forest has never been compared to traditional and potentially more reliable techniques such as regionally stratified sampling and upscaling, and it has rarely been employed with spatial data. Here, we evaluated the performance of Random Forest in upscaling airborne LiDAR (Light Detection and Ranging)-based carbon estimates compared to the stratification approach over a 16-million hectare focal area of the Western Amazon. We considered two runs of Random Forest, both with and without spatial contextual modeling by including—in the latter case—x, and y position directly in the model. In each case, we set aside 8 million hectares (i.e., half of the focal area) for validation; this rigorous test of Random Forest went above and beyond the internal validation normally compiled by the algorithm (i.e., called “out-of-bag”), which proved insufficient for this spatial application. In this heterogeneous region of Northern Peru, the model with spatial context was the best preforming run of Random Forest, and explained 59% of LiDAR-based carbon estimates within the validation area, compared to 37% for stratification or 43% by Random Forest without spatial context. With the 60% improvement in explained variation, RMSE against validation LiDAR samples improved from 33 to 26 Mg C ha−1 when using Random Forest with spatial context. Our results suggest that spatial context should be considered when using Random Forest, and that doing so may result in substantially improved carbon stock modeling for purposes of climate change mitigation. PMID:24489686

Knowledge, attitude, and practice (KAP) of food hygiene among schools students' in Majmaah city, Saudi Arabia.

PubMed

Almansour, Mohammed; Sami, Waqas; Al-Rashedy, Oliyan Shoqer; Alsaab, Rayan Saad; Alfayez, Abdulrahman Saad; Almarri, Nawaf Rashed

2016-04-01

To determine the level of knowledge, attitude, and practice of food hygiene among primary, intermediate and high school students and explore association, if any, with socio-demographic differences. The observational cross-sectional study was conducted at boy's schools in Majmaah, Kingdom of Saudi Arabia, from February to May 2014. Data was collected using stratified random sampling technique from students aged 8-25 year. Two schools from each level (primary, intermediate and high school) were randomly selected and data was collected from the selected schools using simple random sampling method. A self-administered modified Sharif and Al-Malki questionnaire for knowledge, attitude and practice of food hygiene was used with Arabic translation. The mean age of 377 male students in the study was 14.53±2.647 years. Knowledge levels was less in primary school students compared to high school students (p=0.026). Attitude level was high in primary school students compared to intermediate school students (p< 0.001). No significant difference was observed between groups with regard to practice levels (p=0.152). The students exhibited good practice levels, despite fair knowledge and attitude levels.

Complementary nonparametric analysis of covariance for logistic regression in a randomized clinical trial setting.

PubMed

Tangen, C M; Koch, G G

1999-03-01

In the randomized clinical trial setting, controlling for covariates is expected to produce variance reduction for the treatment parameter estimate and to adjust for random imbalances of covariates between the treatment groups. However, for the logistic regression model, variance reduction is not obviously obtained. This can lead to concerns about the assumptions of the logistic model. We introduce a complementary nonparametric method for covariate adjustment. It provides results that are usually compatible with expectations for analysis of covariance. The only assumptions required are based on randomization and sampling arguments. The resulting treatment parameter is a (unconditional) population average log-odds ratio that has been adjusted for random imbalance of covariates. Data from a randomized clinical trial are used to compare results from the traditional maximum likelihood logistic method with those from the nonparametric logistic method. We examine treatment parameter estimates, corresponding standard errors, and significance levels in models with and without covariate adjustment. In addition, we discuss differences between unconditional population average treatment parameters and conditional subpopulation average treatment parameters. Additional features of the nonparametric method, including stratified (multicenter) and multivariate (multivisit) analyses, are illustrated. Extensions of this methodology to the proportional odds model are also made.

Design and simulation study of the immunization Data Quality Audit (DQA).

PubMed

Woodard, Stacy; Archer, Linda; Zell, Elizabeth; Ronveaux, Olivier; Birmingham, Maureen

2007-08-01

The goal of the Data Quality Audit (DQA) is to assess whether the Global Alliance for Vaccines and Immunization-funded countries are adequately reporting the number of diphtheria-tetanus-pertussis immunizations given, on which the "shares" are awarded. Given that this sampling design is a modified two-stage cluster sample (modified because a stratified, rather than a simple, random sample of health facilities is obtained from the selected clusters); the formula for the calculation of the standard error for the estimate is unknown. An approximated standard error has been proposed, and the first goal of this simulation is to assess the accuracy of the standard error. Results from the simulations based on hypothetical populations were found not to be representative of the actual DQAs that were conducted. Additional simulations were then conducted on the actual DQA data to better access the precision of the DQ with both the original and the increased sample sizes.

Geochemical surveys in the United States in relation to health.

USGS Publications Warehouse

Tourtelot, H.A.

1979-01-01

Geochemical surveys in relation to health may be classified as having one, two or three dimensions. One-dimensional surveys examine relations between concentrations of elements such as Pb in soils and other media and burdens of the same elements in humans, at a given time. The spatial distributions of element concentrations are not investigated. The primary objective of two-dimensional surveys is to map the distributions of element concentrations, commonly according to stratified random sampling designs based on either conceptual landscape units or artificial sampling strata, but systematic sampling intervals have also been used. Political units have defined sample areas that coincide with the units used to accumulate epidemiological data. Element concentrations affected by point sources have also been mapped. Background values, location of natural or technological anomalies and the geographic scale of variation for several elements often are determined. Three-dimensional surveys result when two-dimensional surveys are repeated to detect environmental changes. -Author

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.

Lessons learned and insights from the implementation of a food and physical activity policy to prevent obesity in Mexican schools: An analysis of nationally representative survey results.

PubMed

Théodore, Florence L; Moreno-Saracho, Jessica E; Bonvecchio, Anabelle; Morales-Ruán, María Del Carmen; Tolentino-Mayo, Lizbeth; López-Olmedo, Nancy; Shamah-Levy, Teresa; Rivera, Juan A

2018-01-01

Obesity is a serious problem among children in Mexico. In 2010, the government implemented a national food and physical activity policy in elementary schools, to prevent obesity. The goal of this study is to assess the implementation of this policy, using the logic model from a descriptive survey with national representativeness at the elementary school level and based on a stratified cluster design. We used a systematic random sampling of schools (n = 122), stratified into public and private. We administered questionnaires to 116 principals, 165 members of the Food and Physical Activity Committees, 132 food school food vendors, 119 teachers, 348 parents. This study evidences a significant deviation in implementation from what had been planned. Our lessons learned are the importance to: base the design/implementation of the policy on a theoretical framework, make programs appealing to stakeholders, select concrete and measurable objective or goals, and support stakeholders during the implementation process.

Minnesota dentists׳ attitudes toward the dental therapist workforce model.

PubMed

Blue, Christine M; Rockwood, Todd; Riggs, Sheila

2015-06-01

The purpose of this study was to evaluate dentists' attitudes and perceptions toward dental therapists, a new licensed dental provider in Minnesota. This study employed mixed modes to administer a survey using a stratified random sample of 1000 dentists in Minnesota. The response rate was 55% (AAPOR RR1: n=551/999). Results showed a majority of dentists were opposed to dental therapists performing irreversible procedures. In addition, results identified perceived barriers to hiring a dental therapist and found dentists do not believe dental therapists will alleviate oral health disparity in the State. Published by Elsevier Inc.

Anthelmintic Intake on the Nutritional Status, Hemoglobin Content, and Learning Achievement of the Elementary School Student in Sukarami Palembang

NASA Astrophysics Data System (ADS)

Hartati; Aryanti, S.; Muherman, S. Y.

2017-03-01

The main purpose study was to find out the effect of once a year of 400 mg albendazole on the nutritional status and learning achievement of elementary school students in Sukarami Palembang. Methods study used quasi experimental research with non -equivalent control group pretest-posttest design. This study was conducted in Palembang, South Sumatera for one year. Samples of this study were 1914 students deriving from a systematic stratified random sampling and divided into 2 groups: 986 students for the treatment samples were given 400 mg albendazole and 928 students for the controlled samples were given placebo. The result of this study found that there was a decrease in the prevalence of worm infection both in the treatment and controlled samples. However the number of infected students in the treatment samples decreased. The implication research is the drug albendazole worm declared as the most effective drug to treat intestinal worm infections.

Sampling design for an integrated socioeconomic and ecological survey by using satellite remote sensing and ordination

PubMed Central

Binford, Michael W.; Lee, Tae Jeong; Townsend, Robert M.

2004-01-01

Environmental variability is an important risk factor in rural agricultural communities. Testing models requires empirical sampling that generates data that are representative in both economic and ecological domains. Detrended correspondence analysis of satellite remote sensing data were used to design an effective low-cost sampling protocol for a field study to create an integrated socioeconomic and ecological database when no prior information on ecology of the survey area existed. We stratified the sample for the selection of tambons from various preselected provinces in Thailand based on factor analysis of spectral land-cover classes derived from satellite data. We conducted the survey for the sampled villages in the chosen tambons. The resulting data capture interesting variations in soil productivity and in the timing of good and bad years, which a purely random sample would likely have missed. Thus, this database will allow tests of hypotheses concerning the effect of credit on productivity, the sharing of idiosyncratic risks, and the economic influence of environmental variability. PMID:15254298

Serological status of Canadian cattle for brucellosis, anaplasmosis, and bluetongue in 2007–2008

PubMed Central

Paré, Julie; Geale, Dorothy W.; Koller-Jones, Maria; Hooper-McGrevy, Kathleen; Golsteyn-Thomas, Elizabeth J.; Power, Christine A.

2012-01-01

A national bovine serological survey was conducted to confirm that the prevalence of brucellosis, bluetongue, and anaplasmosis does not exceed 0.02% (95% confidence) in live cattle in Canada. Sampling consisted of a systematic random sample of 15 482 adult cattle slaughtered in federally inspected abattoirs, stratified by province. Samples were tested to detect antibodies for brucellosis, bluetongue, and anaplasmosis. All samples were negative for brucellosis. Three samples were seroreactors to bluetongue, 2 of which originated from the Okanagan Valley in British Columbia and 1 from Ontario, which after follow-up, was considered an atypical result. A total of 244 samples were seroreactors to Anaplasma and follow-up identified infection in Saskatchewan, Manitoba, and Quebec. In conclusion, the Canadian cattle population remains free of brucellosis and free of bluetongue outside the Okanagan Valley. Canada is no longer free of anaplasmosis and will be unable to claim freedom until eradication measures are completed. PMID:23450858

Quantifying Uncertainties from Presence Data Sampling Methods for Species Distribution Modeling: Focused on Vegetation.

NASA Astrophysics Data System (ADS)

Sung, S.; Kim, H. G.; Lee, D. K.; Park, J. H.; Mo, Y.; Kil, S.; Park, C.

2016-12-01

The impact of climate change has been observed throughout the globe. The ecosystem experiences rapid changes such as vegetation shift, species extinction. In these context, Species Distribution Model (SDM) is one of the popular method to project impact of climate change on the ecosystem. SDM basically based on the niche of certain species with means to run SDM present point data is essential to find biological niche of species. To run SDM for plants, there are certain considerations on the characteristics of vegetation. Normally, to make vegetation data in large area, remote sensing techniques are used. In other words, the exact point of presence data has high uncertainties as we select presence data set from polygons and raster dataset. Thus, sampling methods for modeling vegetation presence data should be carefully selected. In this study, we used three different sampling methods for selection of presence data of vegetation: Random sampling, Stratified sampling and Site index based sampling. We used one of the R package BIOMOD2 to access uncertainty from modeling. At the same time, we included BioCLIM variables and other environmental variables as input data. As a result of this study, despite of differences among the 10 SDMs, the sampling methods showed differences in ROC values, random sampling methods showed the lowest ROC value while site index based sampling methods showed the highest ROC value. As a result of this study the uncertainties from presence data sampling methods and SDM can be quantified.

Omega-3 (ω-3) and social skills interventions for reactive aggression and childhood externalizing behavior problems: a randomized, stratified, double-blind, placebo-controlled, factorial trial.

PubMed

Raine, Adrian; Ang, Rebecca P; Choy, Olivia; Hibbeln, Joseph R; Ho, Ringo M-H; Lim, Choon Guan; Lim-Ashworth, Nikki S J; Ling, Shichun; Liu, Jean C J; Ooi, Yoon Phaik; Tan, Yi Ren; Fung, Daniel S S

2018-05-10

While studies suggest that nutritional supplementation may reduce aggressive behavior in children, few have examined their effects on specific forms of aggression. This study tests the primary hypothesis that omega-3 (ω-3), both alone and in conjunction with social skills training, will have particular post-treatment efficacy for reducing childhood reactive aggression relative to baseline. In this randomized, double-blind, stratified, placebo-controlled, factorial trial, a clinical sample of 282 children with externalizing behavior aged 7-16 years was randomized into ω-3 only, social skills only, ω-3 + social skills, and placebo control groups. Treatment duration was 6 months. The primary outcome measure was reactive aggression collected at 0, 3, 6, 9, and 12 months, with antisocial behavior as a secondary outcome. Children in the ω-3-only group showed a short-term reduction (at 3 and 6 months) in self-report reactive aggression, and also a short-term reduction in overall antisocial behavior. Sensitivity analyses and a robustness check replicated significant interaction effects. Effect sizes (d) were small, ranging from 0.17 to 0.31. Findings provide some initial support for the efficacy of ω-3 in reducing reactive aggression over and above standard care (medication and parent training), but yield only preliminary and limited support for the efficacy of ω-3 in reducing overall externalizing behavior in children. Future studies could test further whether ω-3 shows promise in reducing more reactive, impulsive forms of aggression.

Reductions of intimate partner violence resulting from supplementing children with omega-3 fatty acids: A randomized, double-blind, placebo-controlled, stratified, parallel-group trial.

PubMed

Portnoy, Jill; Raine, Adrian; Liu, Jianghong; Hibbeln, Joseph R

2018-05-20

Omega-3 supplementation has been found to reduce externalizing behavior in children. Reciprocal models of parent-child behavior suggest that improving child behavior could lead to improvements in parent behavior, however no study has examined whether omega-3 supplementation in children could reduce intimate partner violence or child maltreatment by their adult caregivers. In this randomized, double-blind, placebo-controlled, stratified, parallel group trial, a community sample of children were randomized to receive either a fruit drink containing 1 gm of omega-3 fats (Smartfish Recharge; Omega-3 group, n = 100) or the same fruit drink without omega-3's (Placebo group, n = 100). Child participants, adult caregivers, and research staff were blinded to group assignment. Adult caregivers reported inter-partner and child-directed physical assault and psychological aggression at baseline, 6 months (end of treatment) and 12 months (6 months post-treatment) using the Conflicts Tactics Scale. Caregivers of children in the omega-3 group reported long-term reductions in psychological aggression in a group × time interaction. Improvements in adult psychological aggression were correlated with improvements in child externalizing behavior scores. No differences were reported for child maltreatment. This study is the first to show that omega-3 supplementation in children can reduce inter-partner psychological aggression among adult caregivers not receiving supplements. Findings suggest that improving child behavior through omega-3 supplementation could have long-term benefits to the family system as a whole. © 2018 Wiley Periodicals, Inc.

Predictors of knowledge about tuberculosis: results from SANHANES I, a national, cross-sectional household survey in South Africa.

PubMed

Naidoo, Pamela; Simbayi, Leickness; Labadarios, Demetre; Ntsepe, Yoliswa; Bikitsha, Nwabisa; Khan, Gadija; Sewpaul, Ronel; Moyo, Sizulu; Rehle, Thomas

2016-03-18

South Africa is one of the 22 high tuberculosis burden countries that contribute 80% of the global tuberculosis cases. Tuberculosis is infectious and due to its rapid and easy transmission route poses a threat to population health. Considering the importance of social and psychological factors in influencing health outcomes, appraising knowledge and awareness of tuberculosis, remain vital for effective tuberculosis control. The main aim of this study was to investigate the factors that predict knowledge about tuberculosis among 18-64 year old adults in South Africa. A cross-sectional survey method was used. Multi-stage disproportionate, stratified cluster sampling was used to select households within enumeration areas stratified by province and locality type. Based on the Human Sciences Research Council 2007 master sample, 500 Enumerator Areas representative of the socio-demographic profile of South Africa were identified and a random sample of 20 households was randomly selected from each Enumerator Area, yielding an overall sample of 10,000 households. The tuberculosis module contained in the South African National Health And Nutrition Examination Survey I was the only module that examined the social determinants of an infectious disease. This module was questionnaire-based with no biomarkers obtained to screen for the presence of tuberculosis disease among the participants. Data was collected by administering a researcher developed individual level questionnaire. Simple and multiple linear regression was used to determine the independent variables associated with tuberculosis knowledge. Half the sample (52.6%) was female and the majority of the respondents were black African (76.5%). More than two thirds (68.0%) resided in urban areas, 56.9% did not complete high school and half were not in formal employment. Significant predictors of tuberculosis knowledge were race, sex, completion of high school, being in employment, having a diagnosis of the disease in ones' life-time and learning about tuberculosis from television, brochures, health workers, and teachers. To reduce the burden of tuberculosis in South Africa, media campaigns targeting both rural and urban communities should include conveying accurate information about the disease. Policy makers should also address structural barriers that vulnerable communities face.

Prevalence and correlates of problematic smartphone use in a large random sample of Chinese undergraduates.

PubMed

Long, Jiang; Liu, Tie-Qiao; Liao, Yan-Hui; Qi, Chang; He, Hao-Yu; Chen, Shu-Bao; Billieux, Joël

2016-11-17

Smartphones are becoming a daily necessity for most undergraduates in Mainland China. Because the present scenario of problematic smartphone use (PSU) is largely unexplored, in the current study we aimed to estimate the prevalence of PSU and to screen suitable predictors for PSU among Chinese undergraduates in the framework of the stress-coping theory. A sample of 1062 undergraduate smartphone users was recruited by means of the stratified cluster random sampling strategy between April and May 2015. The Problematic Cellular Phone Use Questionnaire was used to identify PSU. We evaluated five candidate risk factors for PSU by using logistic regression analysis while controlling for demographic characteristics and specific features of smartphone use. The prevalence of PSU among Chinese undergraduates was estimated to be 21.3%. The risk factors for PSU were majoring in the humanities, high monthly income from the family (≥1500 RMB), serious emotional symptoms, high perceived stress, and perfectionism-related factors (high doubts about actions, high parental expectations). PSU among undergraduates appears to be ubiquitous and thus constitutes a public health issue in Mainland China. Although further longitudinal studies are required to test whether PSU is a transient phenomenon or a chronic and progressive condition, our study successfully identified socio-demographic and psychological risk factors for PSU. These results, obtained from a random and thus representative sample of undergraduates, opens up new avenues in terms of prevention and regulation policies.

Design of a Phase III cluster randomized trial to assess the efficacy and safety of a malaria transmission blocking vaccine.

PubMed

Delrieu, Isabelle; Leboulleux, Didier; Ivinson, Karen; Gessner, Bradford D

2015-03-24

Vaccines interrupting Plasmodium falciparum malaria transmission targeting sexual, sporogonic, or mosquito-stage antigens (SSM-VIMT) are currently under development to reduce malaria transmission. An international group of malaria experts was established to evaluate the feasibility and optimal design of a Phase III cluster randomized trial (CRT) that could support regulatory review and approval of an SSM-VIMT. The consensus design is a CRT with a sentinel population randomly selected from defined inner and buffer zones in each cluster, a cluster size sufficient to assess true vaccine efficacy in the inner zone, and inclusion of ongoing assessment of vaccine impact stratified by distance of residence from the cluster edge. Trials should be conducted first in areas of moderate transmission, where SSM-VIMT impact should be greatest. Sample size estimates suggest that such a trial is feasible, and within the range of previously supported trials of malaria interventions, although substantial issues to implementation exist. Copyright © 2015 Elsevier Ltd. All rights reserved.

Increasing Medicaid child health screenings: the effectiveness of mailed pamphlets, phone calls, and home visits.

PubMed Central

Selby-Harrington, M; Sorenson, J R; Quade, D; Stearns, S C; Tesh, A S; Donat, P L

1995-01-01

OBJECTIVES. A randomized controlled trial was conducted to test the effectiveness and cost effectiveness of three outreach interventions to promote well-child screening for children on Medicaid. METHODS. In rural North Carolina, a random sample of 2053 families with children due or overdue for screening was stratified according to the presence of a home phone. Families were randomly assigned to receive a mailed pamphlet and letter, a phone call, or a home visit outreach intervention, or the usual (control) method of informing at Medicaid intake. RESULTS. All interventions produced more screenings than the control method, but increases were significant only for families with phones. Among families with phones, a home visit was the most effective intervention but a phone call was the most cost-effective. However, absolute rates of effectiveness were low, and incremental costs per effect were high. CONCLUSIONS. Pamphlets, phone calls, and home visits by nurses were minimally effective for increasing well-child screenings. Alternate outreach methods are needed, especially for families without phones. PMID:7573627

Interactive boundary delineation of agricultural lands using graphics workstations

NASA Technical Reports Server (NTRS)

Cheng, Thomas D.; Angelici, Gary L.; Slye, Robert E.; Ma, Matt

1992-01-01

A review is presented of the computer-assisted stratification and sampling (CASS) system developed to delineate the boundaries of sample units for survey procedures. CASS stratifies the sampling units by land-cover and land-use type, employing image-processing software and hardware. This procedure generates coverage areas and the boundaries of stratified sampling units that are utilized for subsequent sampling procedures from which agricultural statistics are developed.

Assessing soil carbon vulnerability in the Western USA by geospatial modeling of pyrogenic and particulate carbon stocks

NASA Astrophysics Data System (ADS)

Ahmed, Zia U.; Woodbury, Peter B.; Sanderman, Jonathan; Hawke, Bruce; Jauss, Verena; Solomon, Dawit; Lehmann, Johannes

2017-02-01

To predict how land management practices and climate change will affect soil carbon cycling, improved understanding of factors controlling soil organic carbon fractions at large spatial scales is needed. We analyzed total soil organic (SOC) as well as pyrogenic (PyC), particulate (POC), and other soil organic carbon (OOC) fractions in surface layers from 650 stratified-sampling locations throughout Colorado, Kansas, New Mexico, and Wyoming. PyC varied from 0.29 to 18.0 mg C g-1 soil with a mean of 4.05 mg C g-1 soil. The mean PyC was 34.6% of the SOC and ranged from 11.8 to 96.6%. Both POC and PyC were highest in forests and canyon bottoms. In the best random forest regression model, normalized vegetation index (NDVI), mean annual precipitation (MAP), mean annual temperature (MAT), and elevation were ranked as the top four important variables determining PyC and POC variability. Random forests regression kriging (RFK) with environmental covariables improved predictions over ordinary kriging by 20 and 7% for PyC and POC, respectively. Based on RFK, 8% of the study area was dominated (≥50% of SOC) by PyC and less than 1% was dominated by POC. Furthermore, based on spatial analysis of the ratio of POC to PyC, we estimated that about 16% of the study area is medium to highly vulnerable to SOC mineralization in surface soil. These are the first results to characterize PyC and POC stocks geospatially using stratified sampling scheme at the scale of 1,000,000 km2, and the methods are scalable to other regions.

Sleep Promotion Program for Improving Sleep Behaviors in Adolescents: A Randomized Controlled Pilot Study

PubMed Central

John, Bindu; Bellipady, Sumanth Shetty; Bhat, Shrinivasa Undaru

2016-01-01

Aims. The purpose of this pilot trial was to determine the efficacy of sleep promotion program to adapt it for the use of adolescents studying in various schools of Mangalore, India, and evaluate the feasibility issues before conducting a randomized controlled trial in a larger sample of adolescents. Methods. A randomized controlled trial design with stratified random sampling method was used. Fifty-eight adolescents were selected (mean age: 14.02 ± 2.15 years; intervention group, n = 34; control group, n = 24). Self-report questionnaires, including sociodemographic questionnaire with some additional questions on sleep and activities, Sleep Hygiene Index, Pittsburgh Sleep Quality Index, The Cleveland Adolescent Sleepiness Questionnaire, and PedsQL™ Present Functioning Visual Analogue Scale, were used. Results. Insufficient weekday-weekend sleep duration with increasing age of adolescents was observed. The program revealed a significant effect in the experimental group over the control group in overall sleep quality, sleep onset latency, sleep duration, daytime sleepiness, and emotional and overall distress. No significant effect was observed in sleep hygiene and other sleep parameters. All target variables showed significant correlations with each other. Conclusion. The intervention holds a promise for improving the sleep behaviors in healthy adolescents. However, the effect of the sleep promotion program treatment has yet to be proven through a future research. This trial is registered with ISRCTN13083118. PMID:27088040

Evaluating cost-efficiency and accuracy of hunter harvest survey designs

USGS Publications Warehouse

Lukacs, P.M.; Gude, J.A.; Russell, R.E.; Ackerman, B.B.

2011-01-01

Effective management of harvested wildlife often requires accurate estimates of the number of animals harvested annually by hunters. A variety of techniques exist to obtain harvest data, such as hunter surveys, check stations, mandatory reporting requirements, and voluntary reporting of harvest. Agencies responsible for managing harvested wildlife such as deer (Odocoileus spp.), elk (Cervus elaphus), and pronghorn (Antilocapra americana) are challenged with balancing the cost of data collection versus the value of the information obtained. We compared precision, bias, and relative cost of several common strategies, including hunter self-reporting and random sampling, for estimating hunter harvest using a realistic set of simulations. Self-reporting with a follow-up survey of hunters who did not report produces the best estimate of harvest in terms of precision and bias, but it is also, by far, the most expensive technique. Self-reporting with no followup survey risks very large bias in harvest estimates, and the cost increases with increased response rate. Probability-based sampling provides a substantial cost savings, though accuracy can be affected by nonresponse bias. We recommend stratified random sampling with a calibration estimator used to reweight the sample based on the proportions of hunters responding in each covariate category as the best option for balancing cost and accuracy. ?? 2011 The Wildlife Society.

The association between pre-hypertension status and oxidative stress markers related to atherosclerotic disease: the ATTICA study.

PubMed

Chrysohoou, Christina; Panagiotakos, Demosthenes B; Pitsavos, Christos; Skoumas, John; Economou, Manolis; Papadimitriou, Lambros; Stefanadis, Christodoulos

2007-05-01

We sought to evaluate the association between pre-hypertension status and oxidative stress markers (total antioxidant capacity (TAC) and oxidized low density lipoprotein (LDL)), in a random sample of cardiovascular disease-free adults. The ATTICA study is a cross-sectional population-based survey that conducted in Attica region during 2001-2002. Based on a multistage and stratified random sampling, 1514 men and 1528 women (18-89 years old) were enrolled. The survey included a detailed interview; blood samples collected after 12h of fasting and, among other clinical measurements, status of blood pressure levels was evaluated. Six hundred and fifty-three men (43%) and 535 women (35%) were defined as pre-hypertensives. Both systolic and diastolic blood pressures were inversely correlated with TAC (p<0.001) and positively correlated to oxidized LDL (p<0.001). Particularly, compared to normotensive subjects, pre-hypertensives had 7% lower TAC levels (p<0.001) and 15% higher oxidized LDL levels (p<0.05), after correcting for multiple comparisons and adjusting for age, body mass index, blood lipids, glucose, food groups consumed and other potential confounders. Studying a large sample of cardiovascular disease-free adults, we revealed an association of pre-hypertension with oxidative stress markers linking to atherosclerotic process.

Incidence of migraine and tension-type headache in three different populations at risk within the German DMKG headache study.

PubMed

Khil, Laura; Pfaffenrath, Volker; Straube, Andreas; Evers, Stefan; Berger, Klaus

2012-03-01

Unlike the prevalence, the incidence of headache disorders has attracted only little attention in epidemiological research. Different definitions of the 'population at risk' among the few published migraine and tension-type headache incidence studies limit their comparability and warrant further research. Therefore, we analysed data from the German Migraine and Headache Society (DMKG). Incidences were assessed in the general population in Germany via standardized headache questions using the International Classification of Headache Disorders, 2nd Edition (ICHD-2). The population was drawn from a 5-year age-group- stratified and gender-stratified random sample from the population register. Of the 1312 baseline participants examined between 2003 and 2004, 1122 (85.5%) participated in the follow-up in 2006 and were the basis for three different populations at risk. We found that the three populations differed in size, age, gender and incidence estimate. The total sample incidence of migraine ranged between 0% and 3.3% and of tension-type headache between 5.3% and 9.2% depending on the definition of 'at risk'. We concluded that one significant problem in headache incidence estimation is the definition of 'at risk', limiting comparability. Thus, this study supports the need for a common definition for prospective headache incidence estimations.

Design of dry sand soil stratified sampler

NASA Astrophysics Data System (ADS)

Li, Erkang; Chen, Wei; Feng, Xiao; Liao, Hongbo; Liang, Xiaodong

2018-04-01

This paper presents a design of a stratified sampler for dry sand soil, which can be used for stratified sampling of loose sand under certain conditions. Our group designed the mechanical structure of a portable, single - person, dry sandy soil stratified sampler. We have set up a mathematical model for the sampler. It lays the foundation for further development of design research.

Forest resource inventory assessment in Gunung Rara Forest Reserve, Sabah, using stratified field sampling

Treesearch

Kamaruzaman Jusoff

2000-01-01

The objective of this paper is to assess the current timber volume by stratified sampling on a proposed plantation area. The study area is located in Gunung Rara Forest Reserve in the district of Tawau, Sabah, Malaysia.

Design and simulation of stratified probability digital receiver with application to the multipath communication

NASA Technical Reports Server (NTRS)

Deal, J. H.

1975-01-01

One approach to the problem of simplifying complex nonlinear filtering algorithms is through using stratified probability approximations where the continuous probability density functions of certain random variables are represented by discrete mass approximations. This technique is developed in this paper and used to simplify the filtering algorithms developed for the optimum receiver for signals corrupted by both additive and multiplicative noise.

Inventory of forest resources (including water) by multi-level sampling. [nine northern Virginia coastal plain counties

NASA Technical Reports Server (NTRS)

Aldrich, R. C.; Dana, R. W.; Roberts, E. H. (Principal Investigator)

1977-01-01

The author has identified the following significant results. A stratified random sample using LANDSAT band 5 and 7 panchromatic prints resulted in estimates of water in counties with sampling errors less than + or - 9% (67% probability level). A forest inventory using a four band LANDSAT color composite resulted in estimates of forest area by counties that were within + or - 6.7% and + or - 3.7% respectively (67% probability level). Estimates of forest area for counties by computer assisted techniques were within + or - 21% of operational forest survey figures and for all counties the difference was only one percent. Correlations of airborne terrain reflectance measurements with LANDSAT radiance verified a linear atmospheric model with an additive (path radiance) term and multiplicative (transmittance) term. Coefficients of determination for 28 of the 32 modeling attempts, not adverseley affected by rain shower occurring between the times of LANDSAT passage and aircraft overflights, exceeded 0.83.

Framing Child Sexual Abuse: A Longitudinal Content Analysis of Newspaper and Television Coverage, 2002-2012.

PubMed

Weatherred, Jane Long

2017-01-01

The way in which the news media frame child sexual abuse can influence public perception. This content analysis of the child sexual abuse coverage of eight national news organizations in the United States from 2002 to 2012 includes the two dominant events of the Catholic Church and Pennsylvania State University child sexual abuse scandals. Census and systematic stratified sampling techniques were applied to articles obtained from the Lexis/Nexis Academic database, resulting in a sample of 503 articles. Intercoder reliability was ensured by double coding a randomly selected sample. Study findings indicate a shift in the attribution of responsibility of child sexual abuse among news organizations over the past decade from an individual-level problem with individual-level solutions to a societal-level problem with institutional culpability. Nevertheless, individual-level solutions continue to be framed as the best possible solution.

Field size, length, and width distributions based on LACIE ground truth data. [large area crop inventory experiment

NASA Technical Reports Server (NTRS)

Pitts, D. E.; Badhwar, G.

1980-01-01

The development of agricultural remote sensing systems requires knowledge of agricultural field size distributions so that the sensors, sampling frames, image interpretation schemes, registration systems, and classification systems can be properly designed. Malila et al. (1976) studied the field size distribution for wheat and all other crops in two Kansas LACIE (Large Area Crop Inventory Experiment) intensive test sites using ground observations of the crops and measurements of their field areas based on current year rectified aerial photomaps. The field area and size distributions reported in the present investigation are derived from a representative subset of a stratified random sample of LACIE sample segments. In contrast to previous work, the obtained results indicate that most field-size distributions are not log-normally distributed. The most common field size observed in this study was 10 acres for most crops studied.

Extricating Sex and Gender in Air Pollution Research: A Community-Based Study on Cardinal Symptoms of Exposure

PubMed Central

Oiamo, Tor H.; Luginaah, Isaac N.

2013-01-01

This study investigated sex and gender differences in cardinal symptoms of exposure to a mixture of ambient pollutants. A cross sectional population-based study design was utilized in Sarnia, ON, Canada. Stratified random sampling in census tracts of residents aged 18 and over recruited 804 respondents. Respondents completed a community health survey of chronic disease, general health, and socioeconomic indicators. Residential concentrations of NO2, SO2, benzene, toluene, ethylbenzene and o/m/p-xylene were estimated by land use regression on data collected through environmental monitoring. Classification and Regression Tree (CART) analysis was used to identify variables that interacted with sex and cardinal symptoms of exposure, and a series of logistic regression models were built to predict the reporting of five or more cardinal symptoms (5+ CS). Without controlling for confounders, higher pollution ranks increased the odds ratio (OR) of reporting 5+ CS by 28% (p < 0.01; Confidence Interval (CI): 1.07–1.54). Females were 1.52 (p < 0.05; CI: 1.03–2.26) times more likely more likely to report 5+ CS after controlling for income, age and chronic diseases. The CART analysis showed that allergies and occupational exposure classified the sample into the most homogenous groups of males and females. The likelihood of reporting 5+ CS among females was higher after stratifying the sample based on occupational exposure. However, stratifying by allergic disease resulted in no significant sex difference in symptom reporting. The results confirmed previous research that found pre-existing health conditions to increase susceptibility to ambient air pollution, but additionally indicated that stronger effects on females is partly due to autoimmune disorders. Furthermore, gender differences in occupational exposure confound the effect size of exposure in studies based on residential levels of air pollution. PMID:23975108

Helicity dynamics in stratified turbulence in the absence of forcing.

PubMed

Rorai, C; Rosenberg, D; Pouquet, A; Mininni, P D

2013-06-01

A numerical study of decaying stably stratified flows is performed. Relatively high stratification (Froude number ≈10(-2)-10(-1)) and moderate Reynolds (Re) numbers (Re≈ 3-6×10(3)) are considered and a particular emphasis is placed on the role of helicity (velocity-vorticity correlations), which is not an invariant of the nondissipative equations. The problem is tackled by integrating the Boussinesq equations in a periodic cubical domain using different initial conditions: a nonhelical Taylor-Green (TG) flow, a fully helical Beltrami [Arnold-Beltrami-Childress (ABC)] flow, and random flows with a tunable helicity. We show that for stratified ABC flows helicity undergoes a substantially slower decay than for unstratified ABC flows. This fact is likely associated to the combined effect of stratification and large-scale coherent structures. Indeed, when the latter are missing, as in random flows, helicity is rapidly destroyed by the onset of gravitational waves. A type of large-scale dissipative "cyclostrophic" balance can be invoked to explain this behavior. No production of helicity is observed, contrary to the case of rotating and stratified flows. When helicity survives in the system, it strongly affects the temporal energy decay and the energy distribution among Fourier modes. We discover in fact that the decay rate of energy for stratified helical flows is much slower than for stratified nonhelical flows and can be considered with a phenomenological model in a way similar to what is done for unstratified rotating flows. We also show that helicity, when strong, has a measurable effect on the Fourier spectra, in particular at scales larger than the buoyancy scale, for which it displays a rather flat scaling associated with vertical shear, as observed in the planetary boundary layer.

A comparative study of the health record cards in primary schools of Delhi.

PubMed

Handa, Ajay; Gupta, Sanjay; Tiwari, V K

2008-11-01

A comparative study was undertaken to understand the various measures required to strengthen and improve the health record cards (HRC) of various schools that subsequently help in improving the medical examination of children. By using a multi stage stratified random sampling method, 24 schools from Delhi, eight each from three broad categories of (i) corporation schools, (ii) other government schools, (iii) private schools were included in the study. The study finding revealed that in most of the government schools the health record cards were properly developed and structured as per the recommendations of various committee, though they are always in short supply.

Employee resourcing strategies and universities' corporate image: A survey dataset.

PubMed

Falola, Hezekiah Olubusayo; Oludayo, Olumuyiwa Akinrole; Olokundun, Maxwell Ayodele; Salau, Odunayo Paul; Ibidunni, Ayodotun Stephen; Igbinoba, Ebe

2018-06-01

The data examined the effect of employee resourcing strategies on corporate image. The data were generated from a total of 500 copies of questionnaire administered to the academic staff of the six (6) selected private Universities in Southwest, Nigeria, out of which four hundred and forty-three (443) were retrieved. Stratified and simple random sampling techniques were used to select the respondents for this study. Descriptive and Linear Regression, were used for the presentation of the data. Mean score was used as statistical tool of analysis. Therefore, the data presented in this article is made available to facilitate further and more comprehensive investigation on the subject matter.

Mapping permafrost in the boreal forest with Thematic Mapper satellite data

NASA Technical Reports Server (NTRS)

Morrissey, L. A.; Strong, L. L.; Card, D. H.

1986-01-01

A geographic data base incorporating Landsat TM data was used to develop and evaluate logistic discriminant functions for predicting the distribution of permafrost in a boreal forest watershed. The data base included both satellite-derived information and ancillary map data. Five permafrost classifications were developed from a stratified random sample of the data base and evaluated by comparison with a photo-interpreted permafrost map using contingency table analysis and soil temperatures recorded at sites within the watershed. A classification using a TM thermal band and a TM-derived vegetation map as independent variables yielded the highest mapping accuracy for all permafrost categories.

Exploring Oral Health Beliefs and Behaviour Among Tibetan Immigrants of Bylakkupe.

PubMed

Sivakumar, Vivek; Jain, Jithesh; Battur, Hemanth; Patil, Pavan Uday; Lingaraj, Sunil; Palliyal, Shanavaz

2016-01-01

To explore the oral health beliefs and behaviour among Tibetan immigrants of Bylakkupe village. A stratified random sampling technique involving 366 Tibetan monks in Bylakkupe monasteries was used in this study. The oral health beliefs were measured using a pre-tested questionnaire. The results showed that seriousness was higher compared to other domains in the health belief model. Further, as the duration of the stay increased, the perceived importance was also higher among the population studied. The results show that in general, although the seriousness of oral health was high among the participants, the perceived benefit of dental treatment was relatively low.

A comparison of selection at list time and time-stratified sampling for estimating suspended sediment loads

Treesearch

Robert B. Thomas; Jack Lewis

1993-01-01

Time-stratified sampling of sediment for estimating suspended load is introduced and compared to selection at list time (SALT) sampling. Both methods provide unbiased estimates of load and variance. The magnitude of the variance of the two methods is compared using five storm populations of suspended sediment flux derived from turbidity data. Under like conditions,...

The epidemiology of sepsis in Brazilian intensive care units (the Sepsis PREvalence Assessment Database, SPREAD): an observational study.

PubMed

Machado, Flavia R; Cavalcanti, Alexandre Biasi; Bozza, Fernando Augusto; Ferreira, Elaine M; Angotti Carrara, Fernanda Sousa; Sousa, Juliana Lubarino; Caixeta, Noemi; Salomao, Reinaldo; Angus, Derek C; Pontes Azevedo, Luciano Cesar

2017-11-01

The sepsis burden on acute care services in middle-income countries is a cause for concern. We estimated incidence, prevalence, and mortality of sepsis in adult Brazilian intensive care units (ICUs) and association of ICU organisational factors with outcome. We did a 1-day point prevalence study with follow-up of patients in ICU with sepsis in a nationally representative pseudo-random sample. We produced a sampling frame initially stratified by geographical region. Each stratum was then stratified by hospitals' main source of income (serving general public vs privately insured individuals) and ICU size (ten or fewer beds vs more than ten beds), finally generating 40 strata. In each stratum we selected a random sample of ICUs so as to enrol the total required beds in 1690 Brazilian adult ICUs. We followed up patients until hospital discharge censored at 60 days, estimated incidence from prevalence and length of stay, and generated national estimates. We assessed mortality prognostic factors using random-effects logistic regression models. On Feb 27, 2014, 227 (72%) of 317 ICUs that were randomly selected provided data on 2632 patients, of whom 794 had sepsis (30·2 septic patients per 100 ICU beds, 95% CI 28·4-31·9). The ICU sepsis incidence was 36·3 per 1000 patient-days (95% CI 29·8-44·0) and mortality was observed in 439 (55·7%) of 788 patients (95% CI 52·2-59·2). Low availability of resources (odds ratio [OR] 1·67, 95% CI 1·02-2·75, p=0·045) and adequacy of treatment (OR 0·56, 0·37-0·84, p=0·006) were independently associated with mortality. The projected incidence rate is 290 per 100 000 population (95% CI 237·9-351·2) of adult cases of ICU-treated sepsis per year, which yields about 420 000 cases annually, of whom 230 000 die in hospital. The incidence, prevalence, and mortality of ICU-treated sepsis is high in Brazil. Outcome varies considerably, and is associated with access to adequate resources and treatment. Our results show the burden of sepsis in resource-limited settings, highlighting the need to establish programmes aiming for sepsis prevention, early diagnosis, and adequate treatment. Fundação de Apoio a Pesquisa do Estado de São Paulo (FAPESP). Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of sex education on adolescents' use of condoms: applying the Solomon four-group design.

PubMed

Kvalem, I L; Sundet, J M; Rivø, K I; Eilertsen, D A; Bakketeig, L S

1996-02-01

A school-based sex education program was developed in order to prevent sexually transmitted diseases and unwanted pregnancies. A Solomon four-group design, with random assignment to the different conditions, was used to evaluate an intervention based on cognitive social learning theory and social influence theory. The main goal of the intervention was to increase use of condoms. A stratified sample of 124 classes (2,411 students) was drawn at random from all the upper secondary schools (high schools/colleges) in one county in Norway. The results indicate a consistent interaction between pretest and intervention, which seems to have an effect on condom use. Pretest or intervention alone did not contribute to this effect. The interaction effect appeared among the students with few sexual partners. Several possible explanations to the observed interaction effect and the implication for future interventions are discussed.

Quasi-Likelihood Techniques in a Logistic Regression Equation for Identifying Simulium damnosum s.l. Larval Habitats Intra-cluster Covariates in Togo.

PubMed

Jacob, Benjamin G; Novak, Robert J; Toe, Laurent; Sanfo, Moussa S; Afriyie, Abena N; Ibrahim, Mohammed A; Griffith, Daniel A; Unnasch, Thomas R

2012-01-01

The standard methods for regression analyses of clustered riverine larval habitat data of Simulium damnosum s.l. a major black-fly vector of Onchoceriasis, postulate models relating observational ecological-sampled parameter estimators to prolific habitats without accounting for residual intra-cluster error correlation effects. Generally, this correlation comes from two sources: (1) the design of the random effects and their assumed covariance from the multiple levels within the regression model; and, (2) the correlation structure of the residuals. Unfortunately, inconspicuous errors in residual intra-cluster correlation estimates can overstate precision in forecasted S.damnosum s.l. riverine larval habitat explanatory attributes regardless how they are treated (e.g., independent, autoregressive, Toeplitz, etc). In this research, the geographical locations for multiple riverine-based S. damnosum s.l. larval ecosystem habitats sampled from 2 pre-established epidemiological sites in Togo were identified and recorded from July 2009 to June 2010. Initially the data was aggregated into proc genmod. An agglomerative hierarchical residual cluster-based analysis was then performed. The sampled clustered study site data was then analyzed for statistical correlations using Monthly Biting Rates (MBR). Euclidean distance measurements and terrain-related geomorphological statistics were then generated in ArcGIS. A digital overlay was then performed also in ArcGIS using the georeferenced ground coordinates of high and low density clusters stratified by Annual Biting Rates (ABR). This data was overlain onto multitemporal sub-meter pixel resolution satellite data (i.e., QuickBird 0.61m wavbands ). Orthogonal spatial filter eigenvectors were then generated in SAS/GIS. Univariate and non-linear regression-based models (i.e., Logistic, Poisson and Negative Binomial) were also employed to determine probability distributions and to identify statistically significant parameter estimators from the sampled data. Thereafter, Durbin-Watson test statistics were used to test the null hypothesis that the regression residuals were not autocorrelated against the alternative that the residuals followed an autoregressive process in AUTOREG. Bayesian uncertainty matrices were also constructed employing normal priors for each of the sampled estimators in PROC MCMC. The residuals revealed both spatially structured and unstructured error effects in the high and low ABR-stratified clusters. The analyses also revealed that the estimators, levels of turbidity and presence of rocks were statistically significant for the high-ABR-stratified clusters, while the estimators distance between habitats and floating vegetation were important for the low-ABR-stratified cluster. Varying and constant coefficient regression models, ABR- stratified GIS-generated clusters, sub-meter resolution satellite imagery, a robust residual intra-cluster diagnostic test, MBR-based histograms, eigendecomposition spatial filter algorithms and Bayesian matrices can enable accurate autoregressive estimation of latent uncertainity affects and other residual error probabilities (i.e., heteroskedasticity) for testing correlations between georeferenced S. damnosum s.l. riverine larval habitat estimators. The asymptotic distribution of the resulting residual adjusted intra-cluster predictor error autocovariate coefficients can thereafter be established while estimates of the asymptotic variance can lead to the construction of approximate confidence intervals for accurately targeting productive S. damnosum s.l habitats based on spatiotemporal field-sampled count data.

The prevalence of domestic violence within different socio-economic classes in Central Trinidad.

PubMed

Nagassar, R P; Rawlins, J M; Sampson, N R; Zackerali, J; Chankadyal, K; Ramasir, C; Boodram, R

2010-01-01

Domestic violence is a medical and social issue that often leads to negative consequences for society. This paper examines the association between the prevalence of domestic violence in relation to the different socio-economic classes in Central Trinidad. The paper also explores the major perceived causes of physical abuse in Central Trinidad. Participants were selected using a two-stage stratified sampling method within the Couva district. Households, each contributing one participant, were stratified into different socioeconomic classes (SES Class) and each stratum size (or its share in the sample) was determined by the portion of its size in the sampling frame to the total sample; then its members were randomly selected. The sampling method attempted to balance and then minimize racial, age, cultural biases and confounding factors. The participant chosen had to be older than 16-years of age, female and a resident of the household. If more than one female was at home, the most senior was interviewed. The study found a statistically significant relationship between verbal abuse (p = 0.0017), physical abuse (p = 0.0012) and financial abuse (p = 0.001) and socio-economic class. For all the socio-economic classes considered, the highest prevalence of domestic violence occurred amongst the working class and lower middle socio-economic classes. The most prominent reasons cited for the physical violence was drug and alcohol abuse (37%) and communication differences (16.3%). These were the other two main perceived causes of the violence. The power of the study was 0.78 and the all strata prevalence of domestic violence was 41%. Domestic violence was reported within all socio-economic class groupings but it was most prevalent within the working class and lower middle socio-economic classes. The major perceived cause of domestic violence was alcohol/drug abuse.

How Big of a Problem is Analytic Error in Secondary Analyses of Survey Data?

PubMed

West, Brady T; Sakshaug, Joseph W; Aurelien, Guy Alain S

2016-01-01

Secondary analyses of survey data collected from large probability samples of persons or establishments further scientific progress in many fields. The complex design features of these samples improve data collection efficiency, but also require analysts to account for these features when conducting analysis. Unfortunately, many secondary analysts from fields outside of statistics, biostatistics, and survey methodology do not have adequate training in this area, and as a result may apply incorrect statistical methods when analyzing these survey data sets. This in turn could lead to the publication of incorrect inferences based on the survey data that effectively negate the resources dedicated to these surveys. In this article, we build on the results of a preliminary meta-analysis of 100 peer-reviewed journal articles presenting analyses of data from a variety of national health surveys, which suggested that analytic errors may be extremely prevalent in these types of investigations. We first perform a meta-analysis of a stratified random sample of 145 additional research products analyzing survey data from the Scientists and Engineers Statistical Data System (SESTAT), which describes features of the U.S. Science and Engineering workforce, and examine trends in the prevalence of analytic error across the decades used to stratify the sample. We once again find that analytic errors appear to be quite prevalent in these studies. Next, we present several example analyses of real SESTAT data, and demonstrate that a failure to perform these analyses correctly can result in substantially biased estimates with standard errors that do not adequately reflect complex sample design features. Collectively, the results of this investigation suggest that reviewers of this type of research need to pay much closer attention to the analytic methods employed by researchers attempting to publish or present secondary analyses of survey data.

How Big of a Problem is Analytic Error in Secondary Analyses of Survey Data?

PubMed Central

West, Brady T.; Sakshaug, Joseph W.; Aurelien, Guy Alain S.

2016-01-01

Secondary analyses of survey data collected from large probability samples of persons or establishments further scientific progress in many fields. The complex design features of these samples improve data collection efficiency, but also require analysts to account for these features when conducting analysis. Unfortunately, many secondary analysts from fields outside of statistics, biostatistics, and survey methodology do not have adequate training in this area, and as a result may apply incorrect statistical methods when analyzing these survey data sets. This in turn could lead to the publication of incorrect inferences based on the survey data that effectively negate the resources dedicated to these surveys. In this article, we build on the results of a preliminary meta-analysis of 100 peer-reviewed journal articles presenting analyses of data from a variety of national health surveys, which suggested that analytic errors may be extremely prevalent in these types of investigations. We first perform a meta-analysis of a stratified random sample of 145 additional research products analyzing survey data from the Scientists and Engineers Statistical Data System (SESTAT), which describes features of the U.S. Science and Engineering workforce, and examine trends in the prevalence of analytic error across the decades used to stratify the sample. We once again find that analytic errors appear to be quite prevalent in these studies. Next, we present several example analyses of real SESTAT data, and demonstrate that a failure to perform these analyses correctly can result in substantially biased estimates with standard errors that do not adequately reflect complex sample design features. Collectively, the results of this investigation suggest that reviewers of this type of research need to pay much closer attention to the analytic methods employed by researchers attempting to publish or present secondary analyses of survey data. PMID:27355817

Single-particle dispersion in stably stratified turbulence

NASA Astrophysics Data System (ADS)

Sujovolsky, N. E.; Mininni, P. D.; Rast, M. P.

2018-03-01

We present models for single-particle dispersion in vertical and horizontal directions of stably stratified flows. The model in the vertical direction is based on the observed Lagrangian spectrum of the vertical velocity, while the model in the horizontal direction is a combination of a continuous-time eddy-constrained random walk process with a contribution to transport from horizontal winds. Transport at times larger than the Lagrangian turnover time is not universal and dependent on these winds. The models yield results in good agreement with direct numerical simulations of stratified turbulence, for which single-particle dispersion differs from the well-studied case of homogeneous and isotropic turbulence.

Support of personalized medicine through risk-stratified treatment recommendations - an environmental scan of clinical practice guidelines

PubMed Central

2013-01-01

Background Risk-stratified treatment recommendations facilitate treatment decision-making that balances patient-specific risks and preferences. It is unclear if and how such recommendations are developed in clinical practice guidelines (CPGs). Our aim was to assess if and how CPGs develop risk-stratified treatment recommendations for the prevention or treatment of common chronic diseases. Methods We searched the United States National Guideline Clearinghouse for US, Canadian and National Institute for Health and Clinical Excellence (United Kingdom) CPGs for heart disease, stroke, cancer, chronic obstructive pulmonary disease and diabetes that make risk-stratified treatment recommendations. We included only those CPGs that made risk-stratified treatment recommendations based on risk assessment tools. Two reviewers independently identified CPGs and extracted information on recommended risk assessment tools; type of evidence about treatment benefits and harms; methods for linking risk estimates to treatment evidence and for developing treatment thresholds; and consideration of patient preferences. Results We identified 20 CPGs that made risk-stratified treatment recommendations out of 133 CPGs that made any type of treatment recommendations for the chronic diseases considered in this study. Of the included 20 CPGs, 16 (80%) used evidence about treatment benefits from randomized controlled trials, meta-analyses or other guidelines, and the source of evidence was unclear in the remaining four (20%) CPGs. Nine CPGs (45%) used evidence on harms from randomized controlled trials or observational studies, while 11 CPGs (55%) did not clearly refer to harms. Nine CPGs (45%) explained how risk prediction and evidence about treatments effects were linked (for example, applying estimates of relative risk reductions to absolute risks), but only one CPG (5%) assessed benefit and harm quantitatively and three CPGs (15%) explicitly reported consideration of patient preferences. Conclusions Only a small proportion of CPGs for chronic diseases make risk-stratified treatment recommendations with a focus on heart disease and stroke prevention, diabetes and breast cancer. For most CPGs it is unclear how risk-stratified treatment recommendations were developed. As a consequence, it is uncertain if CPGs support patients and physicians in finding an acceptable benefit- harm balance that reflects both profile-specific outcome risks and preferences. PMID:23302096

Statistical uncertainty analysis applied to the DRAGONv4 code lattice calculations and based on JENDL-4 covariance data

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

Hernandez-Solis, A.; Demaziere, C.; Ekberg, C.

2012-07-01

In this paper, multi-group microscopic cross-section uncertainty is propagated through the DRAGON (Version 4) lattice code, in order to perform uncertainty analysis on k{infinity} and 2-group homogenized macroscopic cross-sections predictions. A statistical methodology is employed for such purposes, where cross-sections of certain isotopes of various elements belonging to the 172 groups DRAGLIB library format, are considered as normal random variables. This library is based on JENDL-4 data, because JENDL-4 contains the largest amount of isotopic covariance matrixes among the different major nuclear data libraries. The aim is to propagate multi-group nuclide uncertainty by running the DRAGONv4 code 500 times, andmore » to assess the output uncertainty of a test case corresponding to a 17 x 17 PWR fuel assembly segment without poison. The chosen sampling strategy for the current study is Latin Hypercube Sampling (LHS). The quasi-random LHS allows a much better coverage of the input uncertainties than simple random sampling (SRS) because it densely stratifies across the range of each input probability distribution. Output uncertainty assessment is based on the tolerance limits concept, where the sample formed by the code calculations infers to cover 95% of the output population with at least a 95% of confidence. This analysis is the first attempt to propagate parameter uncertainties of modern multi-group libraries, which are used to feed advanced lattice codes that perform state of the art resonant self-shielding calculations such as DRAGONv4. (authors)« less

Use of psychotherapy in a representative adult community sample in São Paulo, Brazil

PubMed Central

Blay, Sergio L.; Fillenbaum, Gerda G.; da Silva, Paula Freitas R.; Peluso, Erica T.

2014-01-01

Little is known about the use of psychotherapy to treat common mental disorders in a major city in a middle income country. Data come from in-home interviews with a stratified random sample of 2,000 community residents age 18–65 in the city of São Paulo, Brazil. The information obtained included sociodemographic characteristics; psychotropic drugs; mental status; and lifetime, previous 12 months, and current use of psychotherapy. Logistic regression was used to examine determinants of use of psychotherapy. Of the sample, 22.7% met General Health Questionnaire-12 criteria for common mental disorders. Lifetime, previous 12 months, and current use of psychotherapy were reported by 14.6%, 4.6%, and 2.3% of the sample respectively. Users were typically women, more educated, higher income, not married, unemployed, with common mental disorders. Further analysis found that 47% (with higher education and income) paid out-of-pocket, and 53% used psychotropic medication. Psychotherapy does not appear to be the preferred treatment for common mental disorders. PMID:25118139

State-of-the-art practices in farmland biodiversity monitoring for North America and Europe.

PubMed

Herzog, Felix; Franklin, Janet

2016-12-01

Policy makers and farmers need to know the status of farmland biodiversity in order to meet conservation goals and evaluate management options. Based on a review of 11 monitoring programs in Europe and North America and on related literature, we identify the design choices or attributes of a program that balance monitoring costs and usefulness for stakeholders. A useful program monitors habitats, vascular plants, and possibly faunal groups (ecosystem service providers, charismatic species) using a stratified random sample of the agricultural landscape, including marginal and intensive regions. The size of landscape samples varies with the grain of the agricultural landscape; for example, samples are smaller in Europe and larger in North America. Raw data are collected in a rolling survey, which distributes sampling over several years. Sufficient practical experience is now available to implement broad monitoring schemes on both continents. Technological developments in remote sensing, metagenomics, and social media may offer new opportunities for affordable farmland biodiversity monitoring and help to lower the overall costs of monitoring programs.

Landsat image and sample design for water reservoirs (Rapel dam Central Chile).

PubMed

Lavanderos, L; Pozo, M E; Pattillo, C; Miranda, H

1990-01-01

Spatial heterogeneity of the Rapel reservoir surface waters is analyzed through Landsat images. The image digital counts are used with the aim or developing an aprioristic quantitative sample design.Natural horizontal stratification of the Rapel Reservoir (Central Chile) is produced mainly by suspended solids. The spatial heterogeneity conditions of the reservoir for the Spring 86-Summer 87 period were determined by qualitative analysis and image processing of the MSS Landsat, bands 1 and 3. The space-time variations of the different observed strata obtained with multitemporal image analysis.A random stratified sample design (r.s.s.d) was developed, based on the digital counts statistical analysis. Strata population size as well as the average, variance and sampling size of the digital counts were obtained by the r.s.s.d method.Stratification determined by analysis of satellite images were later correlated with ground data. Though the stratification of the reservoir is constant over time, the shape and size of the strata varys.

The Danish National Health Survey 2010. Study design and respondent characteristics.

PubMed

Christensen, Anne Illemann; Ekholm, Ola; Glümer, Charlotte; Andreasen, Anne Helms; Hvidberg, Michael Falk; Kristensen, Peter Lund; Larsen, Finn Breinholt; Ortiz, Britta; Juel, Knud

2012-06-01

In 2010 the five Danish regions and the National Institute of Public Health at the University of Southern Denmark conducted a national representative health survey among the adult population in Denmark. This paper describes the study design and the sample and study population as well as the content of the questionnaire. The survey was based on five regional stratified random samples and one national random sample. The samples were mutually exclusive. A total of 298,550 individuals (16 years or older) were invited to participate. Information was collected using a mixed mode approach (paper and web questionnaires). A questionnaire with a minimum of 52 core questions was used in all six subsamples. Calibrated weights were computed in order to take account of the complex survey design and reduce non-response bias. In all, 177,639 individuals completed the questionnaire (59.5%). The response rate varied from 52.3% in the Capital Region of Denmark sample to 65.5% in the North Denmark Region sample. The response rate was particularly low among young men, unmarried people and among individuals with a different ethnic background than Danish. The survey was a result of extensive national cooperation across sectors, which makes it unique in its field of application, e.g. health surveillance, planning and prioritizing public health initiatives and research. However, the low response rate in some subgroups of the study population can pose problems in generalizing data, and efforts to increase the response rate will be important in the forthcoming surveys.

Adjunctive Mitomycin C or Amniotic Membrane Transplantation for Ahmed Glaucoma Valve Implantation: A Randomized Clinical Trial.

PubMed

Yazdani, Shahin; Mahboobipour, Hassan; Pakravan, Mohammad; Doozandeh, Azadeh; Ghahari, Elham

2016-05-01

To determine whether adjunctive mitomycin C (MMC) or amniotic membrane transplantation (AMT) improve the outcomes of Ahmed glaucoma valve (AGV) implantation. This double-blind, stratified, 3-armed randomized clinical trial includes 75 eyes of 75 patients aged 7 to 75 years with refractory glaucoma. Eligible subjects underwent stratified block randomization; eyes were first stratified to surgery in the superior or inferior quadrants based on feasibility; in each subgroup, eyes were randomly assigned to the study arms using random blocks: conventional AGV implantation (group A, 25 eyes), AGV with MMC (group B, 25 eyes), and AGV with AMT (group C, 25 eyes). The 3 study groups were comparable regarding baseline characteristics and mean follow-up (P=0.288). A total of 68 patients including 23 eyes in group A, 25 eyes in group B, and 20 eyes group C completed the follow-up period and were analyzed. Intraocular pressure was lower in the MMC group only 3 weeks postoperatively (P=0.04) but comparable at other time intervals. Overall success rate was comparable in the 3 groups at 12 months (P=0.217). The number of eyes requiring medications (P=0.30), time to initiation of medications (P=0.13), and number of medications (P=0.22) were comparable. Hypertensive phase was slightly but insignificantly more common with standard surgery (82%) as compared with MMC-augmented (60%) and AMT-augmented (70%) procedures (P=0.23). Complications were comparable over 1 year (P=0.28). Although adjunctive MMC and AMT were safe during AGV implantation, they did not influence success rates or intraocular pressure outcomes. Complications, including hypertensive phase, were also comparable.

Improving depression and enhancing resilience in family dementia caregivers: a pilot randomized placebo-controlled trial of escitalopram.

PubMed

Lavretsky, Helen; Siddarth, Prabha; Irwin, Michael R

2010-02-01

This study examined the potential of an antidepressant drug, escitalopram, to improve depression, resilience to stress, and quality of life in family dementia caregivers in a randomized placebo-controlled double-blinded trial. Forty family caregivers (43-91 years of age, 25 children and 15 spouses; 26 women) who were taking care of their relatives with Alzheimer disease were randomized to receive either escitalopram 10 mg/day or placebo for 12 weeks. Severity of depression, resilience, burden, distress, quality of life, and severity of care-recipient's cognitive and behavioral disturbances were assessed at baseline and over the course of the study. The Hamilton Depression Rating Scale scores at baseline ranged between 10 and 28. The groups were stratified by the diagnosis of major and minor depression. Most outcomes favored escitalopram over placebo. The severity of depression improved, and the remission rate was greater with the drug compared with placebo. Measures of anxiety, resilience, burden, and distress improved on escitalopram compared with placebo. Among caregivers, this small randomized controlled trial found that escitalopram use resulted in improvement in depression, resilience, burden and distress, and quality of life. Our results need to be confirmed in a larger sample.

Slope And Equation of Line: Teach And Analysis In Terms of Emotional Intelligence

NASA Astrophysics Data System (ADS)

Dewi, A. C.; Budiyono; Riyadi

2017-09-01

Slope and equation of line is a sub-material of algebra and is one that is difficult for students to understand. The purpose of this study is to understand and explore the slope and equation so that students feel easy and ultimately improve their academic achievement. Experimental research was conducted by applying Jigsaw II learning model and Teams Games Tournament (TGT) and improvement in emotional intelligence (EI). The study sample was students from 3 different schools who were selected stratified cluster random sampling. The results showed that there is no influence of learning model and EI on academic achievement. This can happen even in the learning process students feel happy and interest. Although research shows different results with most theories, but it is expected that this research can be a good reference for students, teachers, and other researchers.

Simple and Multivariate Relationships Between Spiritual Intelligence with General Health and Happiness.

PubMed

Amirian, Mohammad-Elyas; Fazilat-Pour, Masoud

2016-08-01

The present study examined simple and multivariate relationships of spiritual intelligence with general health and happiness. The employed method was descriptive and correlational. King's Spiritual Quotient scales, GHQ-28 and Oxford Happiness Inventory, are filled out by a sample consisted of 384 students, which were selected using stratified random sampling from the students of Shahid Bahonar University of Kerman. Data are subjected to descriptive and inferential statistics including correlations and multivariate regressions. Bivariate correlations support positive and significant predictive value of spiritual intelligence toward general health and happiness. Further analysis showed that among the Spiritual Intelligence' subscales, Existential Critical Thinking Predicted General Health and Happiness, reversely. In addition, happiness was positively predicted by generation of personal meaning and transcendental awareness. The findings are discussed in line with the previous studies and the relevant theoretical background.

Relationship of hospital organizational culture to patient safety climate in the Veterans Health Administration.

PubMed

Hartmann, Christine W; Meterko, Mark; Rosen, Amy K; Shibei Zhao; Shokeen, Priti; Singer, Sara; Gaba, David M

2009-06-01

Improving safety climate could enhance patient safety, yet little evidence exists regarding the relationship between hospital characteristics and safety climate. This study assessed the relationship between hospitals' organizational culture and safety climate in Veterans Health Administration (VA) hospitals nationally. Data were collected from a sample of employees in a stratified random sample of 30 VA hospitals over a 6-month period (response rate = 50%; n = 4,625). The Patient Safety Climate in Healthcare Organizations (PSCHO) and the Zammuto and Krakower surveys were used to measure safety climate and organizational culture, respectively. Higher levels of safety climate were significantly associated with higher levels of group and entrepreneurial cultures, while lower levels of safety climate were associated with higher levels of hierarchical culture. Hospitals could use these results to design specific interventions aimed at improving safety climate.

[Sexual coercion and abortion: a context of vulnerability among young women].

PubMed

Pilecco, Flávia Bulegon; Knauth, Daniela Riva; Vigo, Álvaro

2011-03-01

This study aims to investigate the relationship between abortion and experiences of sexual coercion. The data came from GRAVAD, a household survey with a stratified random sample of young women (18-24 years) in Rio de Janeiro, Porto Alegre, and Salvador, Brazil. The sample used in this article included 870 interviews of women who reported having become pregnant. Abortion was associated with: a reported experience of sexual coercion, more schooling, failure to obtain first information about sex from parents, and a history of more pregnancies and sexual partners. The association between abortion and sexual coercion reflects a situation of gender vulnerability and reveals young women's precariousness in sex negotiation and reproduction. A veil of silence in public agencies concerning sexual coercion helps perpetuate young women's vulnerability, as it blocks access to the appropriate educational, legal, and health services.

Cognitive and academic functioning of juvenile detainees: implications for correctional populations and public health.

PubMed

Lansing, Amy E; Washburn, Jason J; Abram, Karen M; Thomas, Ursula C; Welty, Leah J; Teplin, Linda A

2014-01-01

Cognitive functioning affects health. This study assessed cognitive functioning among participants in the Northwestern Juvenile Project, a stratified random sample of 1,829 newly detained juveniles (10 to 18 years old) from Cook County, Illinois. The study examined receptive vocabulary, oral reading, arithmetic computation skills, and general intellectual abilities. The sample exhibited impaired overall intellectual functioning and deficits in all areas. Males performed more poorly than females. More than three quarters of males showed below average overall intellectual functioning, and 9 in 10 had below average receptive vocabulary skills. Hispanic and African American males performed more poorly than non-Hispanic White males. The multiple systems that serve delinquent youth--correctional, health, legal, and rehabilitative--must collaborate to tailor needed services to the cognitive level of youth in the juvenile justice system.

Cognitive and academic functioning of juvenile detainees: Implications for correctional populations and public health

PubMed Central

Lansing, Amy E.; Washburn, Jason J.; Abram, Karen M.; Thomas, Ursula C.; Welty, Leah J.; Teplin, Linda A.

2014-01-01

Cognitive functioning affects health. This study assessed cognitive functioning among participants in the Northwestern Juvenile Project, a stratified random sample of 1,829 newly detained juveniles (10-18 years old) from Cook County, Illinois. We examined receptive vocabulary, oral reading, arithmetic computation skills, and general intellectual abilities. Our sample exhibited impaired overall intellectual functioning and deficits in all areas. Males performed more poorly than females overall. More than three-quarters of males showed below average overall intellectual functioning, and nine in ten males had below average receptive vocabulary skills. Hispanic and African American males performed more poorly than non-Hispanic white males; The multiple systems that serve delinquent youth—correctional, health, legal, and rehabilitative—must collaborate to tailor needed services to the cognitive level of youth in the juvenile justice system. PMID:24352405

Composition and concentration of hydrocarbons in sediment samples from the oil producing area of the East Shetland Basin, Scotland.

PubMed

Russell, M; Webster, L; Walsham, P; Packer, G; Dalgarno, E J; McIntosh, A D; Fryer, R J; Moffat, C F

2008-04-01

The East Shetland Basin is one of the areas that the Fisheries Research Services (FRS) has concentrated on to assess the possible impacts of oil exploration and production on the marine environment. A stratified random survey of the sediment was carried out in 2002. TOCs were low across the basin and were positively correlated with grain size. The total PAH concentrations (2- to 6-ring parent and alkylated PAHs, including the 16 US EPA PAHs) were less than 150 microg kg(-1) dry weight and their composition indicated a predominantly pyrolytic input to the basin in 2002. Minor unresolved complex mixtures in the n-alkane profiles indicated a slight petrogenic input but further examination of the biomarkers (hopanes and steranes) showed a mixed North Sea and Middle Eastern source. The Middle Eastern source is likely due to inputs from shipping activity, as it is widely used as bunker fuel. Grid surveys were carried out in 1986, 1988-89 and 1994 and areas were selected for which there was data for all the historic grid surveys and the 2002 stratified random survey. Although referring to only a small part of the East Shetland Basin, comparison with these historic surveys shows clearly that the concentrations of Forties crude oil equivalents and total PAH concentrations were highest in 1988-89 and by 2002 had returned to concentrations the same as or less than observed in the original survey in 1986.

Local Environmental Factors Drive Divergent Grassland Soil Bacterial Communities in the Western Swiss Alps

PubMed Central

Pinto-Figueroa, Eric; Buri, Aline; Spangenberg, Jorge E.; Adatte, Thierry; Guisan, Antoine; van der Meer, Jan Roelof

2016-01-01

ABSTRACT Mountain ecosystems are characterized by a diverse range of climatic and topographic conditions over short distances and are known to shelter a high biodiversity. Despite important progress, still little is known on bacterial diversity in mountain areas. Here, we investigated soil bacterial biogeography at more than 100 sampling sites randomly stratified across a 700-km2 area with 2,200-m elevation gradient in the western Swiss Alps. Bacterial grassland communities were highly diverse, with 12,741 total operational taxonomic units (OTUs) across 100 sites and an average of 2,918 OTUs per site. Bacterial community structure was correlated with local climatic, topographic, and soil physicochemical parameters with high statistical significance. We found pH (correlated with % CaO and % mineral carbon), hydrogen index (correlated with bulk gravimetric water content), and annual average number of frost days during the growing season to be among the groups of the most important environmental drivers of bacterial community structure. In contrast, bacterial community structure was only weakly stratified as a function of elevation. Contrasting patterns were discovered for individual bacterial taxa. Acidobacteria responded both positively and negatively to pH extremes. Various families within the Bacteroidetes responded to available phosphorus levels. Different verrucomicrobial groups responded to electrical conductivity, total organic carbon, water content, and mineral carbon contents. Alpine grassland bacterial communities are thus highly diverse, which is likely due to the large variety of different environmental conditions. These results shed new light on the biodiversity of mountain ecosystems, which were already identified as potentially fragile to anthropogenic influences and climate change. IMPORTANCE This article addresses the question of how microbial communities in alpine regions are dependent on local climatic and soil physicochemical variables. We benefit from a unique 700-km2 study region in the western Swiss Alps region, which has been exhaustively studied for macro-organismal and fungal ecology, and for topoclimatic modeling of future ecological trends, but without taking into account soil bacterial diversity. Here, we present an in-depth biogeographical characterization of the bacterial community diversity in this alpine region across 100 randomly stratified sites, using 56 environmental variables. Our exhaustive sampling ensured the detection of ecological trends with high statistical robustness. Our data both confirm previously observed general trends and show many new detailed trends for a wide range of bacterial taxonomic groups and environmental parameters. PMID:27542929

Chloroacetanilide herbicide metabolites in Wisconsin groundwater: 2001 survey results.

PubMed

Postle, Jeffrey K; Rheineck, Bruce D; Allen, Paula E; Baldock, Jon O; Cook, Cody J; Zogbaum, Randy; Vandenbrook, James P

2004-10-15

A survey of agricultural chemicals in Wisconsin groundwater was conducted between October 2000 and April 2001 to obtain a current picture of agricultural chemicals in groundwater used for private drinking water. A stratified, random sampling procedure was used to select 336 sampling locations. Water from private drinking water wells randomly selected from within the 336 sampling locations was analyzed for 18 compounds including herbicides, herbicide metabolites, and nitrate. This report focuses on the frequency and concentration of chloroacetanilide herbicides and their metabolites. Analysis of data resulted in an estimated proportion of 38+/-5.0% of wells that contained detectable levels of a herbicide or herbicide metabolite. The most commonly detected compound was alachlor ESA with a proportion estimate of 28+/-4.6%. Other detected compounds in order of prevalence were metolachlor ESA, metolachlor OA, alachlor OA, acetochlor ESA, and parent alachlor. Estimates of the mean concentration for the detects ranged from 0.15+/-0.082 microg/L for acetochlor ESA to 1.8+/-0.60 microg/L for alachlor OA. Water quality standards have not been developed for these chloroacetanilide herbicide metabolites. The results of this survey emphasize the need for toxicological assessments of herbicide metabolite compounds and establishment of water quality standards at the state and federal levels.

A Repeat Random Survey of the Prevalence of Falsified and Substandard Antimalarials in the Lao PDR: A Change for the Better

PubMed Central

Tabernero, Patricia; Mayxay, Mayfong; Culzoni, María Julia; Dwivedi, Prabha; Swamidoss, Isabel; Allan, Elizabeth Louise; Khanthavong, Maniphone; Phonlavong, Chindaphone; Vilayhong, Chantala; Yeuchaixiong, Sengchanh; Sichanh, Chanvilay; Sengaloundeth, Sivong; Kaur, Harparkash; Fernández, Facundo M.; Green, Michael D.; Newton, Paul N.

2015-01-01

In 2003, a stratified random sample survey was conducted in the Lao People's Democratic Republic (Laos) to study the availability and quality of antimalarials in the private sector. In 2012, this survey was repeated to allow a statistically valid analysis of change through time. The counterfeit detection device 3 (CD-3) was used to assess packaging quality in the field and HPLC and mass spectroscopy analysis chemical analysis performed. The availability of oral artesunate monotherapies had significantly decreased from 22.9% (22) of 96 outlets in southern Laos in 2003 to 4.8% (7) of 144 outlets in 2012 (P < 0.0001). All the samples collected in the 2012 survey contained the correct active pharmaceutical ingredients (APIs) in contrast to the 21 (84%) falsified artesunate samples found in the 2003 survey. Although none of the medicines found in 2012 survey had evidence for falsification, 25.4% (37) of the samples were outside the 90–110% pharmacopeial limits of the label claim, suggesting that they were substandard or degraded. Results obtained from this survey show that patients are still exposed to poorly manufactured drugs or to ineffective medicines such as chloroquine. The quality of artemisinin-based combination therapies (ACTs) used in Laos needs to be monitored, since falsified ACTs would have devastating consequences in public health. PMID:25897062

[MESGI50 study: description of a cohort on Maturity and Satisfactory Ageing].

PubMed

Corominas Barnadas, Josep María; López-Pousa, Secundino; Vilalta-Franch, Joan; Calvó-Perxas, Laia; Juvinyà Canal, Dolors; Garre-Olmo, Josep

To describe the demographic, health and socio-economic characteristics of the participants in the Study on Maturity and Satisfactory Ageing in Girona (MESGI50 study). Population-based Study linked to the Survey of Health, Ageing, and Retirement in Europe (SHARE). The reference population was the inhabitants of the province of Girona (Spain) aged 50 and over. A probabilistic two-stage stratified cluster sampling according to the number of inhabitants and the degree of ageing of the population was used. Twenty-eight municipalities were randomly selected according to their type (demographically aged or young), and then stratified by the population size. The response rate was 65% with a mean of 1.7 eligible individuals per household and a final sample of 2,065 households and 3,331 participants. The design effect was 1.27. 52.9% were women and the mean age was 66.9 years (SD=11.5). The self-rated health status, hand grip strength, restriction in daily life activities and depressive symptomatology increased with age and more markedly in women. There were differences in alcohol consumption and eating patterns depending on the area of residence. The demographic, health and socio-economic characteristics during the ageing process differ depending on age group, gender, and area of residence. Copyright © 2016 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

Gambling problems in the family--a stratified probability sample study of prevalence and reported consequences.

PubMed

Wenzel, Hanne Gro; Oren, Anita; Bakken, Inger Johanne

2008-12-16

Prior studies on the impact of problem gambling in the family mainly include help-seeking populations with small numbers of participants. The objective of the present stratified probability sample study was to explore the epidemiology of problem gambling in the family in the general population. Men and women 16-74 years-old randomly selected from the Norwegian national population database received an invitation to participate in this postal questionnaire study. The response rate was 36.1% (3,483/9,638). Given the lack of validated criteria, two survey questions ("Have you ever noticed that a close relative spent more and more money on gambling?" and "Have you ever experienced that a close relative lied to you about how much he/she gambles?") were extrapolated from the Lie/Bet Screen for pathological gambling. Respondents answering "yes" to both questions were defined as Concerned Significant Others (CSOs). Overall, 2.0% of the study population was defined as CSOs. Young age, female gender, and divorced marital status were factors positively associated with being a CSO. CSOs often reported to have experienced conflicts in the family related to gambling, worsening of the family's financial situation, and impaired mental and physical health. Problematic gambling behaviour not only affects the gambling individual but also has a strong impact on the quality of life of family members.

Gambling problems in the family – A stratified probability sample study of prevalence and reported consequences

PubMed Central

Wenzel, Hanne Gro; Øren, Anita; Bakken, Inger Johanne

2008-01-01

Background Prior studies on the impact of problem gambling in the family mainly include help-seeking populations with small numbers of participants. The objective of the present stratified probability sample study was to explore the epidemiology of problem gambling in the family in the general population. Methods Men and women 16–74 years-old randomly selected from the Norwegian national population database received an invitation to participate in this postal questionnaire study. The response rate was 36.1% (3,483/9,638). Given the lack of validated criteria, two survey questions ("Have you ever noticed that a close relative spent more and more money on gambling?" and "Have you ever experienced that a close relative lied to you about how much he/she gambles?") were extrapolated from the Lie/Bet Screen for pathological gambling. Respondents answering "yes" to both questions were defined as Concerned Significant Others (CSOs). Results Overall, 2.0% of the study population was defined as CSOs. Young age, female gender, and divorced marital status were factors positively associated with being a CSO. CSOs often reported to have experienced conflicts in the family related to gambling, worsening of the family's financial situation, and impaired mental and physical health. Conclusion Problematic gambling behaviour not only affects the gambling individual but also has a strong impact on the quality of life of family members. PMID:19087339

Panels of tumor-derived RNA markers in peripheral blood of patients with non-small cell lung cancer: their dependence on age, gender and clinical stages.

PubMed

Chian, Chih-Feng; Hwang, Yi-Ting; Terng, Harn-Jing; Lee, Shih-Chun; Chao, Tsui-Yi; Chang, Hung; Ho, Ching-Liang; Wu, Yi-Ying; Perng, Wann-Cherng

2016-08-02

Peripheral blood mononuclear cell (PBMC)-derived gene signatures were investigated for their potential use in the early detection of non-small cell lung cancer (NSCLC). In our study, 187 patients with NSCLC and 310 age- and gender-matched controls, and an independent set containing 29 patients for validation were included. Eight significant NSCLC-associated genes were identified, including DUSP6, EIF2S3, GRB2, MDM2, NF1, POLDIP2, RNF4, and WEE1. The logistic model containing these significant markers was able to distinguish subjects with NSCLC from controls with an excellent performance, 80.7% sensitivity, 90.6% specificity, and an area under the receiver operating characteristic curve (AUC) of 0.924. Repeated random sub-sampling for 100 times was used to validate the performance of classification training models with an average AUC of 0.92. Additional cross-validation using the independent set resulted in the sensitivity 75.86%. Furthermore, six age/gender-dependent genes: CPEB4, EIF2S3, GRB2, MCM4, RNF4, and STAT2 were identified using age and gender stratification approach. STAT2 and WEE1 were explored as stage-dependent using stage-stratified subpopulation. We conclude that these logistic models using different signatures for total and stratified samples are potential complementary tools for assessing the risk of NSCLC.

A guide for the utilization of Health Insurance Review and Assessment Service National Patient Samples

PubMed Central

Kim, Logyoung; Kim, Jee-Ae; Kim, Sanghyun

2014-01-01

The claims data of the Health Insurance Review and Assessment Service (HIRA) is an important source of information for healthcare service research. The claims data of HIRA is collected when healthcare service providers submit a claim to HIRA to be reimbursed for a service that they provided to patients. To improve the accessibility of healthcare service researchers to claims data of HIRA, HIRA has developed the Patient Samples which are extracted using a stratified randomized sampling method. The Patient Samples of HIRA consist of five tables: a table for general information (Table 20) containing socio-demographic information such as gender, age and medical aid, indicators for inpatient and outpatient services; a table for specific information on healthcare services provided (Table 30); a table for diagnostic information (Table 40); a table for outpatient prescriptions (Table 53) and a table for information on healthcare service providers (Table of providers). Researchers who are interested in using the Patient Sample data for research can apply via HIRA’s website (https://www.hira.or.kr). PMID:25078381

Adapting to Life after Hurricane Katrina and the Deepwater Horizon Oil Spill: An Examination of Psychological Resilience and Depression on the Mississippi Gulf Coast.

PubMed

Blackmon, Bret J; Lee, Joohee; Cochran, David M; Kar, Bandana; Rehner, Timothy A; Baker, Alvin M

2017-01-02

The purpose of this study was to examine relationships among depression, psychological resilience, and other sociodemographic factors of individuals who were highly exposed to Hurricane Katrina in 2005 and the Deepwater Horizon Oil Spill in 2010. A spatially stratified random sample of 294 Mississippi Gulf Coast residents living in close proximity to the Gulf of Mexico were surveyed. Findings indicated that low education attainment, financial hardship, and disaster-related damages increased the likelihood of depression, whereas psychological resilience and having health insurance reduced the odds of depression. Implications for enhancing psychological resilience and increasing access to health insurance are discussed.

Principals' attitudes regarding inclusion of children with autism in Pennsylvania public schools.

PubMed

Horrocks, Judy L; White, George; Roberts, Laura

2008-09-01

This study sought to identify the attitudes that principals held regarding the inclusion of students with disabilities, and the relationship between their attitudes and their placement recommendations for children with autism and to identify the relationship between specific demographic factors and attitudes toward inclusion and placement. A stratified random sample was drawn from the active list of 3,070 principals in the Pennsylvania public schools. From 1,500 surveys, 571 principal responses were received. The most significant factor in predicting both a positive attitude toward inclusion of children with disabilities and higher recommendations of placements for children with autism was the principal's belief that children with autism could be included in a regular education classroom.

A comparison of top and middle level women administrators in social work, nursing, and education: career supports and barriers.

PubMed

Collins, S K

1984-01-01

Presented in this article are findings from a descriptive study of a national stratified random sample of 259 women administrators in social work, nursing, and education. Subjects responded to a 54 item, mailed questionnaire about their career experiences. The author explores career support from parents and persons within their work organizations. Barriers of sex discrimination and difficulties balancing career and family responsibilities are included. Finally, the extent to which the women administrators provided career assistance to other women is discussed. Comparisons between the three fields and between top and middle management levels are emphasized. Recommendations are made for increasing women's opportunities for career achievement within the fields studied.

Predictors of job satisfaction among academics at an Iranian university.

PubMed

Zarafshani, Kiumars; Alibaygi, Amir Hossein

2009-04-01

The overall job satisfaction of 128 faculty of Razi University in Iran was investigated using a modified version of the Minnesota Satisfaction Questionnaire to elicit information in this stratified random sample. Faculty members were most satisfied with intrinsic aspects of the work such as "social service," "activity," and "ability utilization" and less satisfied with extrinsic aspects of work such as "security," "university policies," and "compensation." Publication counts and years of teaching experience contributed significantly to the prediction of overall job satisfaction among these faculty members. Intervention efforts must involve socializing faculty in the early stages of their careers, encouraging them to engage in research activities and write for reputable journals, while providing compensation and job security.

Risk of Mycobacterium tuberculosis infection in Somalia: national tuberculin survey 2006.

PubMed

Munim, A; Rajab, Y; Barker, A; Daniel, M; Williams, B

2008-01-01

To estimate the annual risk of tuberculosis (TB) infection (ARTI) in Somalia a tuberculin survey was conducted in February/March 2006. Stratified cluster sampling was carried out within the 18 regions and 101 randomly selected primary schools. Tuberculin testing was done in 10 680 grade 1 schoolchildren. Transverse tuberculin reaction size was measured 72 hours later. The number of children with a satisfactory test read was 10 364. The overall BCG coverage was 54%. Based on frequency distribution of tuberculin reaction sizes, the ARTI in Somalia was estimated at 2.2% (confidence interval: 1.5%-3.2%). There was an annual decline of 2.6% comparing with a previous study in 1956.

An Exploratory Case Study of a Sexual Assault Telephone Hotline: Training and Practice Implications.

PubMed

Colvin, Marianna L; Pruett, Jana A; Young, Stephen M; Holosko, Michael J

2016-06-29

Using archival data, this case study systematically examines telephone calls received by a regional sexual assault hotline in the Southeastern United States over a 5-year period. A stratified random sample (n = 383) reveals that hotline staff require diversity and depth in knowledge and skills, demonstrated by the hotline's primary use as a crisis service, combined with notable use by long-term survivors. Findings include the utility of the hotline by survivors and community stakeholders, categories of assault, the time gap between incidents occurring and contacting the hotline, call severity and urgency, and services and referrals provided. Implications for training, practice, and future research are discussed. © The Author(s) 2016.

Comorbid Visual and Psychiatric Disabilities Among the Chinese Elderly: A National Population-Based Survey.

PubMed

Guo, Chao; Wang, Zhenjie; Li, Ning; Chen, Gong; Zheng, Xiaoying

2017-12-01

To estimate the prevalence of, and association between, co-morbid visual and psychiatric disabilities among elderly (>65 years-of-age) persons in China. Random representative samples were obtained using multistage, stratified, cluster sampling, with probabilities proportional to size. Standard weighting procedures were used to construct sample weights that reflected this multistage, stratified cluster sampling survey scheme. Logistic regression models were used to elucidate associations between visual and psychiatric disabilities. Among the Chinese elderly, >160,000 persons have co-morbid visual and psychiatric disabilities. The weighted prevalence among this cohort is 123.7 per 100,000 persons. A higher prevalence of co-morbid visual and psychiatric disabilities was found in the oldest-old (p<0.001); women (65-79 years-of-age, p=0.001; ≥80 years-of-age, p=0.004); illiterate (65-79 years-of-age, p<0.001; ≥80 years-of-age, p=0.02); and single elders (65-79 years-of-age, p=0.01; ≥80 years-of-age, p=0.001). Presence of a visual disability was significantly associated with a higher risk of having a psychiatric disability among persons aged ≥80 years-of-age [adjusted odds ratio, 1.24; 95% confidence interval (CI), 1.03-1.54]. A significant number of Chinese elderly persons were living with co-morbid visual and psychiatric disabilities. To address the challenge of these co-morbid disorders among Chinese elders, it is incumbent upon the government to implement additional and more comprehensive prevention and rehabilitation strategies for health-care systems, reinforce health promotion among the elderly, and improve accessibility to health-care services.

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

Heimburger, D.C.; Alexander, C.B.; Birch, R.

To test whether changes in folate and vitamin B/sub 12/ nutrition modify the severity of potentially premalignant lesions identified by cytology in sputum samples of smokers, the authors conducted a randomized, controlled prospective intervention trial in smokers with bronchial squamous metaplasia. Seventy-three men with a history of 20 or more pack-years of cigarette smoking who had metaplasia on one or more sputum samples were stratified according to smoking level and randomly assigned to four months' treatment with either placebo or 10 mg of folate plus 500 ..mu..g of hydroxocobalamin. Direct cytological comparison of the two groups after four months showedmore » significantly greater reduction of atypia in the supplemented group. This provides preliminary evidence that atypical bronchial squamous metaplasia may be reduced by supplementation with folate and vitamin B/sub 12/. However, the significance of these findings is tempered by substantial spontaneous variation in sputum cytologies, the small study population, the short duration of the trial, and the supraphysiological doses of folate and B/sub 12/ used. The results should not be construed as pointing to a potential way of preventing lung cancer in individuals who continue to smoke or as supporting self-medication with large doses of folate or B/sub 12/ by smokers.« less

Occupational position and its relation to mental distress in a random sample of Danish residents.

PubMed

Rugulies, Reiner; Madsen, Ida E H; Nielsen, Maj Britt D; Olsen, Lis R; Mortensen, Erik L; Bech, Per

2010-08-01

To analyze the distribution of depressive, anxiety, and somatization symptoms across different occupational positions in a random sample of Danish residents. The study sample consisted of 591 Danish residents (50% women), aged 20-65, drawn from an age- and gender-stratified random sample of the Danish population. Participants filled out a survey that included the 92 item version of the Hopkins Symptom Checklist (SCL-92). We categorized occupational position into seven groups: high- and low-grade non-manual workers, skilled and unskilled manual workers, high- and low-grade self-employed, and unemployed. Compared to the reference group of high-grade non-manual workers, the depressive symptom score was statistically significantly elevated among unskilled manual workers (P = 0.043) and the unemployed (P < 0.001), after adjustment for age, gender, cohabitation, life events, and low household income. The anxiety symptom score was elevated only among the unemployed (P = 0.004). The somatization symptom score was elevated among unskilled manual workers (P = 0.002), the low-grade self-employed (P = 0.023), and the unemployed (P = 0.001). When we analyzed caseness of severe symptoms, we found that unskilled manual workers (OR = 3.27, 95% CI = 1.06-10.04) and the unemployed (OR = 6.20, 95% CI = 1.98-19.42) had a higher prevalence of severe depressive symptoms, compared to the reference group of high-grade non-manual workers. The unemployed also had a higher prevalence of severe somatization symptoms (OR = 6.28, 95% CI = 1.39-28.46). Unskilled manual workers, the unemployed, and, to a lesser extent, the low-grade self-employed showed an increased level of mental distress. Activities to promote mental health in the Danish population should be directed toward these groups.

Evaluation of the Effectiveness of Chemical Dependency Counseling Course Based on Patrick and Partners

PubMed Central

Keshavarz, Yousef; Ghaedi, Sina; Rahimi-Kashani, Mansure

2012-01-01

Background The twelve step program is one of the programs that are administered for overcoming abuse of drugs. In this study, the effectiveness of chemical dependency counseling course was investigated using a hybrid model. Methods In a survey with sample size of 243, participants were selected using stratified random sampling method. A questionnaire was used for collecting data and one sample t-test employed for data analysis. Findings Chemical dependency counseling courses was effective from the point of view of graduates, chiefs of rehabilitation centers, rescuers and their families and ultimately managers of rebirth society, but it was not effective from the point of view of professors and lecturers. The last group evaluated the effectiveness of chemical dependency counseling courses only in performance level. Conclusion It seems that the chemical dependency counseling courses had appropriate effectiveness and led to change in attitudes, increase awareness, knowledge and experience combination and ultimately increased the efficiency of counseling. PMID:24494132

Fall Risk Assessment in Geriatric-Psychiatric Inpatients to Lower Events (FRAGILE).

PubMed

Nanda, Sudip; Dey, Tanujit; Gulstrand, Rudolph E; Cudnik, Daniel; Haller, Harold S

2011-02-01

The objectives of this retrospective case-control study were to identify risk factors of falls in geriatric-psychiatric inpatients and develop a screening tool to accurately predict falls. The study sample consisted of 225 geriatric-psychiatric inpatients at a Midwestern referral facility. The sample included 136 inpatients who fell and a random stratified sample of 89 inpatients who did not fall. Data collected included age, gender, activities of daily living, and nursing parameters such as bathing assistance, bed height, use of bed rails, one-on-one observation, fall warning system, Conley Scale fall risk assessment, medical diagnosis, and medications. History of falls, impaired judgment, impaired gait, dizziness, delusions, delirium, chronic use of sedative or antipsychotic agents, and anticholinergic urinary bladder medications significantly increased fall risk. Alzheimer's disease, acute use of sedative or anti-psychotic agents, and depression reduced fall risk. A falls risk tool, Fall Risk Assessment in Geriatric-psychiatric Inpatients to Lower Events (FRAGILE), was developed for assessment and risk stratification with new diagnoses or medications. Copyright 2011, SLACK Incorporated.

The factors that influence job satisfaction among royal Malaysian customs department employee

NASA Astrophysics Data System (ADS)

Ammar Shafi, Muhammad; Saifullah Rusiman, Mohd; Nor, Maria Elena; Khamis, Azme; Nabilah Syuhada Abdullah, Siti; Syafiq Azmi, Mohd; Sakinah Zainal Abidin, Munirah; Ali, Maselan

2018-04-01

This research aims to spot the factors that influence job satisfaction among Royal Malaysian Customs Department employees. Primary data was used in this research and it was collected from the employees who work in five different departments at Royal Malaysian Customs Department Tower Johor. Those departments were customs department, Internal Taxes, Technical Services, Management and Prevention. The research used stratified random sampling to collect the sample and Structural Equation Modelling (SEM) to measure the relationship between variables using AMOS software. About 127 employees are selected as the respondents from five departments to represent the sample. The result showed that ‘Organizational Commitment’ (p-value = 0.001) has significant and direct effect toward job satisfaction compared to the ‘Stress Condition’ (p-value = 0.819) and ‘Motivation’ factor (p-value = 0.978). It was also concluded that ‘Organizational Commitment’ was the most influential factor toward job satisfaction among Royal Malaysian Customs Department employees at Tower Custom Johor, Johor Bahru.

Contextual Approach with Guided Discovery Learning and Brain Based Learning in Geometry Learning

NASA Astrophysics Data System (ADS)

Kartikaningtyas, V.; Kusmayadi, T. A.; Riyadi

2017-09-01

The aim of this study was to combine the contextual approach with Guided Discovery Learning (GDL) and Brain Based Learning (BBL) in geometry learning of junior high school. Furthermore, this study analysed the effect of contextual approach with GDL and BBL in geometry learning. GDL-contextual and BBL-contextual was built from the steps of GDL and BBL that combined with the principles of contextual approach. To validate the models, it uses quasi experiment which used two experiment groups. The sample had been chosen by stratified cluster random sampling. The sample was 150 students of grade 8th in junior high school. The data were collected through the student’s mathematics achievement test that given after the treatment of each group. The data analysed by using one way ANOVA with different cell. The result shows that GDL-contextual has not different effect than BBL-contextual on mathematics achievement in geometry learning. It means both the two models could be used in mathematics learning as the innovative way in geometry learning.

Lifetime and current sexual assault and harassment victimization rates of active-duty United States Air Force women.

PubMed

Bostock, Deborah J; Daley, James G

2007-09-01

From a stratified random sample, 2,018 active-duty United States Air Force women completed a telephone survey dealing with sexual assault and harassment. The lifetime prevalence of rape among Air Force women (28%) was more than twice as high as the prevalence in a national sample (13%). Nearly half of the military sample had been the victims of rape, molestation, or attempted sexual assault. The majority of both initial rapes (75%) and most recent rapes (56%) involved assault by civilians when the victims were civilians. Family members perpetrated 29% of initial rapes and 33% of most recent rapes. Regarding military status of the perpetrator, 14% of first-time victims were raped by a military member, 26% of multiple-time victims were raped by a military member, 31.8% of military women were sexually harassed by a military supervisor or boss, and 26.7% of military women were sexually harassed by a military coworker.

[Study on correction of data bias caused by different missing mechanisms in survey of medical expenditure among students enrolling in Urban Resident Basic Medical Insurance].

PubMed

Zhang, Haixia; Zhao, Junkang; Gu, Caijiao; Cui, Yan; Rong, Huiying; Meng, Fanlong; Wang, Tong

2015-05-01

The study of the medical expenditure and its influencing factors among the students enrolling in Urban Resident Basic Medical Insurance (URBMI) in Taiyuan indicated that non response bias and selection bias coexist in dependent variable of the survey data. Unlike previous studies only focused on one missing mechanism, a two-stage method to deal with two missing mechanisms simultaneously was suggested in this study, combining multiple imputation with sample selection model. A total of 1 190 questionnaires were returned by the students (or their parents) selected in child care settings, schools and universities in Taiyuan by stratified cluster random sampling in 2012. In the returned questionnaires, 2.52% existed not missing at random (NMAR) of dependent variable and 7.14% existed missing at random (MAR) of dependent variable. First, multiple imputation was conducted for MAR by using completed data, then sample selection model was used to correct NMAR in multiple imputation, and a multi influencing factor analysis model was established. Based on 1 000 times resampling, the best scheme of filling the random missing values is the predictive mean matching (PMM) method under the missing proportion. With this optimal scheme, a two stage survey was conducted. Finally, it was found that the influencing factors on annual medical expenditure among the students enrolling in URBMI in Taiyuan included population group, annual household gross income, affordability of medical insurance expenditure, chronic disease, seeking medical care in hospital, seeking medical care in community health center or private clinic, hospitalization, hospitalization canceled due to certain reason, self medication and acceptable proportion of self-paid medical expenditure. The two-stage method combining multiple imputation with sample selection model can deal with non response bias and selection bias effectively in dependent variable of the survey data.

Group investigation with scientific approach in mathematics learning

NASA Astrophysics Data System (ADS)

Indarti, D.; Mardiyana; Pramudya, I.

2018-03-01

The aim of this research is to find out the effect of learning model toward mathematics achievement. This research is quasi-experimental research. The population of research is all VII grade students of Karanganyar regency in the academic year of 2016/2017. The sample of this research was taken using stratified cluster random sampling technique. Data collection was done based on mathematics achievement test. The data analysis technique used one-way ANOVA following the normality test with liliefors method and homogeneity test with Bartlett method. The results of this research is the mathematics learning using Group Investigation learning model with scientific approach produces the better mathematics learning achievement than learning with conventional model on material of quadrilateral. Group Investigation learning model with scientific approach can be used by the teachers in mathematics learning, especially in the material of quadrilateral, which is can improve the mathematics achievement.

Analysis of cattle breeder’s income in South Kualuh sub-district of Labuhan Batu Utara Regency

NASA Astrophysics Data System (ADS)

Hasnudi; Berutu, I. S.; Daulay, A. H.; Ginting, N.; Sembiring, I.

2018-02-01

Beef cattle breeding is a business of the majority people in South Kualuh Subdistrict among others business. Therefore it is necessary to know the people income of beef cattle farms in the district. This research was conducted in South Kualuh Subdistrict of Labuhan Batu Utara Regency of North Sumatera Province from October to December 2016. This research used survey method with family respondent unit that raising beef cattle. The sample was obtained through Proportional Stratified Random Sampling method and obtained by 97 farmers such as, from Tanjung Pasir village, 64 respondents, Simangalam village was 24 respondents and Lobu Huala village was 9 respondents. Data was analysed by multiple linear regression analysis. The results showed that scale of business, education of farmers positively affect the income of beef cattle farms while the age, breeding experience and the number of family dependents negatively affect to the income of beef cattle farms.

Research Data in Core Journals in Biology, Chemistry, Mathematics, and Physics.

PubMed

Womack, Ryan P

2015-01-01

This study takes a stratified random sample of articles published in 2014 from the top 10 journals in the disciplines of biology, chemistry, mathematics, and physics, as ranked by impact factor. Sampled articles were examined for their reporting of original data or reuse of prior data, and were coded for whether the data was publicly shared or otherwise made available to readers. Other characteristics such as the sharing of software code used for analysis and use of data citation and DOIs for data were examined. The study finds that data sharing practices are still relatively rare in these disciplines' top journals, but that the disciplines have markedly different practices. Biology top journals share original data at the highest rate, and physics top journals share at the lowest rate. Overall, the study finds that within the top journals, only 13% of articles with original data published in 2014 make the data available to others.

Research Data in Core Journals in Biology, Chemistry, Mathematics, and Physics

PubMed Central

Womack, Ryan P.

2015-01-01

This study takes a stratified random sample of articles published in 2014 from the top 10 journals in the disciplines of biology, chemistry, mathematics, and physics, as ranked by impact factor. Sampled articles were examined for their reporting of original data or reuse of prior data, and were coded for whether the data was publicly shared or otherwise made available to readers. Other characteristics such as the sharing of software code used for analysis and use of data citation and DOIs for data were examined. The study finds that data sharing practices are still relatively rare in these disciplines’ top journals, but that the disciplines have markedly different practices. Biology top journals share original data at the highest rate, and physics top journals share at the lowest rate. Overall, the study finds that within the top journals, only 13% of articles with original data published in 2014 make the data available to others. PMID:26636676

The relationship among the resiliency practices in supply chain, financial performance, and competitive advantage in manufacturing firms in Indonesia and Sierra Leone

NASA Astrophysics Data System (ADS)

Musa, I.; Nyoman Pujawan, I.

2018-04-01

Current supply chain management (SCM) has become a potentially treasured way of safeguarding competitive advantage and improving organizational performance since competition is no longer between organizations, but among supply chains. This research conceptualizes and develops four resiliency practices (Flexibility, Redundancy, Collaboration and Agility) and tests the relationships between organizations’ financial performance and competitive advantage in manufacturing firms. The study involves manufacturing firms in Indonesia and Sierra Leone. The study used stratified random sampling to pick a sample size of 95 manufacturing firms, which represented different industrial sectors. The respondents were mainly managers of different manufacturing companies. The relationships proposed in the conceptual framework were tested using correlation analysis. The results indicate that higher levels of resilience practices in manufacturing firms can lead to enhanced competitive advantage and improved financial performance.

Assessing technical performance at diverse ambulatory care sites.

PubMed

Osterweis, M; Bryant, E

1978-01-01

The purpose of the large study reported here was to develop and test methods for assessing the quality of health care that would be broadly applicable to diverse ambulatory care organizations for periodic comparative review. Methodological features included the use of an age-sex stratified random sampling scheme, dependence on medical records as the source of data, a fixed study period year, use of Kessner's tracer methodology (including not only acute and chronic diseases but also screening and immunization rates as indicators), and a fixed tracer matrix at all test sites. This combination of methods proved more efficacious in estimating certain parameters for the total patient populations at each site (including utilization patterns, screening, and immunization rates) and the process of care for acute conditions than it did in examining the process of care for the selected chronic condition. It was found that the actual process of care at all three sites for the three acute conditions (streptococcal pharyngitis, urinary tract infection, and iron deficiency anemia) often differed from the expected process in terms of both diagnostic procedures and treatment. For hypertension, the chronic disease tracer, medical records were frequently a deficient data source from which to draw conclusions about the adequacy of treatment. Several aspects of the study methodology were found to be detrimental to between-site comparisons of the process of care for chronic disease management. The use of an age-sex stratified random sampling scheme resulted in the identification of too few cases of hypertension at some sites for analytic purposes, thereby necessitating supplementary sampling by diagnosis. The use of a fixed study period year resulted in an arbitrary starting point in the course of the disease. Furthermore, in light of the diverse sociodemographic characteristics of the patient populations, the use of a fixed matrix of tracer conditions for all test sites is questionable. The discussion centers on these and other problems encountered in attempting to compare technical performance within diverse ambulatory care organizations and provides some guidelines as to the utility of alternative methods for assessing the quality of health care.

Reaching the Hard-to-Reach: A Probability Sampling Method for Assessing Prevalence of Driving under the Influence after Drinking in Alcohol Outlets

PubMed Central

De Boni, Raquel; do Nascimento Silva, Pedro Luis; Bastos, Francisco Inácio; Pechansky, Flavio; de Vasconcellos, Mauricio Teixeira Leite

2012-01-01

Drinking alcoholic beverages in places such as bars and clubs may be associated with harmful consequences such as violence and impaired driving. However, methods for obtaining probabilistic samples of drivers who drink at these places remain a challenge – since there is no a priori information on this mobile population – and must be continually improved. This paper describes the procedures adopted in the selection of a population-based sample of drivers who drank at alcohol selling outlets in Porto Alegre, Brazil, which we used to estimate the prevalence of intention to drive under the influence of alcohol. The sampling strategy comprises a stratified three-stage cluster sampling: 1) census enumeration areas (CEA) were stratified by alcohol outlets (AO) density and sampled with probability proportional to the number of AOs in each CEA; 2) combinations of outlets and shifts (COS) were stratified by prevalence of alcohol-related traffic crashes and sampled with probability proportional to their squared duration in hours; and, 3) drivers who drank at the selected COS were stratified by their intention to drive and sampled using inverse sampling. Sample weights were calibrated using a post-stratification estimator. 3,118 individuals were approached and 683 drivers interviewed, leading to an estimate that 56.3% (SE = 3,5%) of the drivers intended to drive after drinking in less than one hour after the interview. Prevalence was also estimated by sex and broad age groups. The combined use of stratification and inverse sampling enabled a good trade-off between resource and time allocation, while preserving the ability to generalize the findings. The current strategy can be viewed as a step forward in the efforts to improve surveys and estimation for hard-to-reach, mobile populations. PMID:22514620

Reliability of N-terminal proBNP assay in diagnosis of left ventricular systolic dysfunction within representative and high risk populations.

PubMed

Hobbs, F D R; Davis, R C; Roalfe, A K; Hare, R; Davies, M K

2004-08-01

To determine the performance of a new NT-proBNP assay in comparison with brain natriuretic peptide (BNP) in identifying left ventricular systolic dysfunction (LVSD) in randomly selected community populations. Blood samples were taken prospectively in the community from 591 randomly sampled individuals over the age of 45 years, stratified for age and socioeconomic status and divided into four cohorts (general population; clinically diagnosed heart failure; patients on diuretics; and patients deemed at high risk of heart failure). Definite heart failure (left ventricular ejection fraction (LVEF) < 40%) was identified in 33 people. Samples were handled as though in routine clinical practice. The laboratories undertaking the assays were blinded. Using NT-proBNP to diagnose LVEF < 40% in the general population, a level of > 40 pmol/l had 80% sensitivity, 73% specificity, 5% positive predictive value (PPV), 100% negative predictive value (NPV), and an area under the receiver-operator characteristic curve (AUC) of 76% (95% confidence interval (CI) 46% to 100%). For BNP to diagnose LVSD, a cut off level of > 33 pmol/l had 80% sensitivity, 88% specificity, 10% PPV, 100% NPV, and AUC of 88% (95% CI 75% to 100%). Similar NPVs were found for patients randomly screened from the three other populations. Both NT-proBNP and BNP have value in diagnosing LVSD in a community setting, with similar sensitivities and specificities. Using a high cut off for positivity will confirm the diagnosis of LVSD but will miss cases. At lower cut off values, positive results will require cardiac imaging to confirm LVSD.

Nonprescription Antimicrobial Use in a Primary Care Population in the United States

PubMed Central

Zoorob, Roger; Nash, Susan; Trautner, Barbara W.

2016-01-01

Community antimicrobial resistance rates are high in communities with frequent use of nonprescription antibiotics. Studies addressing nonprescription antibiotic use in the United States have been restricted to Latin American immigrants. We estimated the prevalence of nonprescription antibiotic use in the previous 12 months as well as intended use (intention to use antibiotics without a prescription) and storage of antibiotics and examined patient characteristics associated with nonprescription use in a random sample of adults. We selected private and public primary care clinics that serve ethnically and socioeconomically diverse patients. Within the clinics, we used race/ethnicity-stratified systematic random sampling to choose a random sample of primary care patients. We used a self-administered standardized questionnaire on antibiotic use. Multivariate regression analysis was used to identify independent predictors of nonprescription use. The response rate was 94%. Of 400 respondents, 20 (5%) reported nonprescription use of systemic antibiotics in the last 12 months, 102 (25.4%) reported intended use, and 57 (14.2%) stored antibiotics at home. These rates were similar across race/ethnicity groups. Sources of antibiotics used without prescriptions or stored for future use were stores or pharmacies in the United States, “leftover” antibiotics from previous prescriptions, antibiotics obtained abroad, or antibiotics obtained from a relative or friend. Respiratory symptoms were common reasons for the use of nonprescription antibiotics. In multivariate analyses, public clinic patients, those with less education, and younger patients were more likely to endorse intended use. The problem of nonprescription use is not confined to Latino communities. Community antimicrobial stewardship must include a focus on nonprescription antibiotics. PMID:27401572

Effectiveness Of Horizontal Peer-Assisted Learning In Physical Examination Performance.

PubMed

Shah, Inamullah; Mahboob, Usman; Shah, Sajida

2017-01-01

All students cannot be individually trained in physical examination skills due to faculty and time limitations. Peer-assisted learning (PAL) can solve this dilemma if it is used in undergraduate curriculum. Empirical effectiveness of horizontal peer-assisted learning model has not been reported previously. The objective of this study was to compare horizontal peer-assisted learning (PAL) with expert-assisted learning (EAL) in teaching of physical examination skills. This is a randomized controlled study (Solomon four group design) carried out at a medical school. A total of 120 undergraduate year 5 students were randomized into two groups to undergo training in four areas of physical examination. Stratified random sampling technique was used. Group 1 was trained by EAL while Group 2 by PAL. Half students from both groups were given a pre-test to assess the testing effect. Both groups were given a post-test in the form of an OSCE. Independent samples t-test and paired sample t-test were used as tests of significance. Group 2 scored significantly higher than Group 1. There was significant difference (p=.000) in mean post-test scores of Group-1 (69.98±5.6) and Group-2 (85.27±5.6). Difference in mean scores was not significant (p=.977) between students who had taken the pre-test and those who had not. This study has implications in curriculum development as it provides quantitative evidence indicating that horizontal PAL as a learning strategy can actually replace, rather than augment, expert-assisted learning in teaching clinical skills to undergraduate students.

Influence of marital and educational status on clients' psychosocial adjustment to HIV/AIDS in Calabar, Nigeria.

PubMed

Akpabio, Idongesit I; Uyanah, David A; Osuchukwu, Nelson C; Samson-Akpan, Patience E

2010-06-01

A comparative descriptive design and a stratified random sampling technique were adopted to study the influence of marital and educational status on the psychological, social, and spiritual adjustment of 280 respondents living with HIV/AIDS in two randomly selected clinics within Calabar, Nigeria. A 30 item questionnaire, with a content validity index of 0.92 and a Cronbach's alpha reliability coefficient of 0.94, was used for data collection, with due attention to ethical considerations. The findings showed that marital status had a significant influence on the respondents' psychological and social adjustment but not on their spiritual adjustment. Those that were married and those with higher educational qualifications had better psychological adjustment than those who had never married. The marital and educational status of clients should be considered when conducting education or counseling, making recommendations, or organizing support groups for living with HIV/AIDS. Furthermore, advocacy aimed at meeting the psychosocial needs of single and less-educated clients could enhance their psychosocial adjustment.

Exploring the "legacy" of the Tuskegee Syphilis Study: a follow-up study from the Tuskegee Legacy Project.

PubMed

Katz, Ralph V; Green, B Lee; Kressin, Nancy R; James, Sherman A; Wang, Min Qi; Claudio, Cristina; Russell, Stephanie Luise

2009-02-01

The purpose of this follow-up 2003 3-City Tuskegee Legacy Project (TLP) Study was to validate or refute our prior findings from the 1999-2000 4 City TLP Study, which found no evidence to support the widely acknowledged "legacy" of the Tuskegee Syphilis Study (TSS), ie, that blacks are reluctant to participate in biomedical studies due to their knowledge of the TSS. The TLP Questionnaire was administered in this random-digit-dial telephone survey to a stratified random sample of 1162 black, white, and Puerto Rican Hispanic adults in 3 different US cities. The findings from this current 3-City TLP Study fail to support the widely acknowledged "legacy" of the TSS, as awareness of the TSS was not statistically associated with the willingness to participate in biomedical studies. These findings, being in complete agreement with our previous findings from our 1999-2000 4-City TLP, validate those prior findings.

Exploring the “Legacy” of the Tuskegee Syphilis Study: A Follow-up Study From the Tuskegee Legacy Project

PubMed Central

Katz, Ralph V.; Green, B. Lee; Kressin, Nancy R.; James, Sherman A.; Wang, Min Qi; Claudio, Cristina; Russell, Stephanie Luise

2009-01-01

The purpose of this follow-up 2003 3-City Tuskegee Legacy Project (TLP) Study was to validate or refute our prior findings from the 1999–2000 4 City TLP Study, which found no evidence to support the widely acknowledged “legacy” of the Tuskegee Syphilis Study (TSS), ie, that blacks are reluctant to participate in biomedical studies due to their knowledge of the TSS. The TLP Questionnaire was administered in this random-digit-dial telephone survey to a stratified random sample of 1162 black, white, and Puerto Rican Hispanic adults in 3 different US cities. The findings from this current 3-City TLP Study fail to support the widely acknowledged “legacy” of the TSS, as awareness of the TSS was not statistically associated with the willingness to participate in biomedical studies. These findings, being in complete agreement with our previous findings from our 1999–2000 4-City TLP, validate those prior findings. PMID:19378637

Teacher coaching supported by formative assessment for improving classroom practices.

PubMed

Fabiano, Gregory A; Reddy, Linda A; Dudek, Christopher M

2018-06-01

The present study is a wait-list controlled, randomized study investigating a teacher coaching approach that emphasizes formative assessment and visual performance feedback to enhance elementary school teachers' classroom practices. The coaching model targeted instructional and behavioral management practices as measured by the Classroom Strategies Assessment System (CSAS) Observer and Teacher Forms. The sample included 89 general education teachers, stratified by grade level, and randomly assigned to 1 of 2 conditions: (a) immediate coaching, or (b) waitlist control. Results indicated that, relative to the waitlist control, teachers in immediate coaching demonstrated significantly greater improvements in observations of behavior management strategy use but not for observations of instructional strategy use. Observer- and teacher-completed ratings of behavioral management strategy use at postassessment were significantly improved by both raters; ratings of instructional strategy use were significantly improved for teacher but not observer ratings. A brief coaching intervention improved teachers' use of observed behavior management strategies and self-reported use of behavior management and instructional strategies. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Alcohol- and Drug-Involved Driving in the United States: Methodology for the 2007 National Roadside Survey

ERIC Educational Resources Information Center

Lacey, John H.; Kelley-Baker, Tara; Voas, Robert B.; Romano, Eduardo; Furr-Holden, C. Debra; Torres, Pedro; Berning, Amy

2011-01-01

This article describes the methodology used in the 2007 U.S. National Roadside Survey to estimate the prevalence of alcohol- and drug-impaired driving and alcohol- and drug-involved driving. This study involved randomly stopping drivers at 300 locations across the 48 continental U.S. states at sites selected through a stratified random sampling…

Interest of LQAS method in a survey of HTLV-I infection in Benin (West Africa).

PubMed

Houinato, Dismand; Preux, Pierre-Marie; Charriere, Bénédicte; Massit, Bruno; Avodé, Gilbert; Denis, François; Dumas, Michel; Boutros-Toni, Fernand; Salamon, Roger

2002-02-01

HTLV-I is heterogeneously distributed in Sub-Saharan Africa. Traditional survey methods as cluster sampling could provide information for a country or region of interest. However, they cannot identify small areas with higher prevalences of infection to help in the health policy planning. Identification of such areas could be done by a Lot Quality Assurance Sampling (LQAS) method, which is currently used in industry to identify a poor performance in assembly lines. The LQAS method was used in Atacora (Northern Benin) between March and May 1998 to identify areas with a HTLV-I seroprevalence higher than 4%. Sixty-five subjects were randomly selected in each of 36 communes (lots) of this department. Lots were classified as unacceptable when the sample contained at least one positive subject. The LQAS method identified 25 (69.4 %) communes with a prevalence higher than 4%. Using stratified sampling theory, the overall HTLV-I seroprevalence was 4.5% (95% CI: 3.6-5.4%). These data show the interest of LQAS method application under field conditions to detect clusters of infection.

Biomass energy inventory and mapping system

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

Kasile, J.D.

1993-12-31

A four-stage biomass energy inventory and mapping system was conducted for the entire State of Ohio. The product is a set of maps and an inventory of the State of Ohio. The set of amps and an inventory of the State`s energy biomass resource are to a one kilometer grid square basis on the Universal Transverse Mercator (UTM) system. Each square kilometer is identified and mapped showing total British Thermal Unit (BTU) energy availability. Land cover percentages and BTU values are provided for each of nine biomass strata types for each one kilometer grid square. LANDSAT satellite data was usedmore » as the primary stratifier. The second stage sampling was the photointerpretation of randomly selected one kilometer grid squares that exactly corresponded to the LANDSAT one kilometer grid square classification orientation. Field sampling comprised the third stage of the energy biomass inventory system and was combined with the fourth stage sample of laboratory biomass energy analysis using a Bomb calorimeter and was then used to assign BTU values to the photointerpretation and to adjust the LANDSAT classification. The sampling error for the whole system was 3.91%.« less

Improving depression and enhancing resilience in family dementia caregivers: a pilot randomized placebo-controlled trial of escitalopram

PubMed Central

Lavretsky, H.; Siddarth, P.; Irwin, M. R.

2009-01-01

Background This study examined the potential of an antidepressant drug, escitalopram, to improve depression, resilience to stress, and quality of life in family dementia caregivers in a randomized placebo-controlled double-blind trial. Methods Forty family caregivers (43–91 years of age, 25 children and 15 spouses; 26 women) who were taking care of their relatives with Alzheimer’s disease were randomized to receive either escitalopram 10 mg/day or placebo for 12 weeks. Severity of depression, resilience, burden, distress, quality of life, and severity of care-recipient’s cognitive and behavioral disturbances were assessed at baseline and over the course of the study. The Hamilton Depression Rating Scale (HDRS) scores at baseline ranged between 10–28. The groups were stratified by the diagnosis of major and minor depression. Results Most outcomes favored escitalopram over placebo. The severity of depression improved and the remission rate was greater with the drug compared to placebo. Measures of anxiety, resilience, burden and distress improved on escitalopram compared to placebo. Discussion Among caregivers, this small randomized controlled trial found that escitalopram use resulted in improvement in depression, resilience, burden and distress, and quality of life. Our results need to be confirmed in a larger sample. PMID:20104071

Effectiveness of interactive discussion group in suicide risk assessment among general nurses in Taiwan: a randomized controlled trial.

PubMed

Wu, Chia-Yi; Lin, Yi-Yin; Yeh, Mei Chang; Huang, Lian-Hua; Chen, Shaw-Ji; Liao, Shih-Cheng; Lee, Ming-Been

2014-11-01

The evidence of suicide prevention training for nurses is scarce. Strategies to enhance general nurses' ability in suicide risk assessment are critical to develop effective training programs in general medical settings. This study was aimed to examine the effectiveness of an interactive discussion group in a suicide prevention training program for general nurses. In this randomized study with two groups of pre-post study design, the sample was recruited from the Medical, Surgical, and Emergency/Intensive Care Sectors of a 2000-bed general hospital via stratified randomization. Among the 111 nurses, 57 participants randomly assigned to the control group received a two-hour baseline suicide gatekeeper lecture, and 54 participants assigning to the experimental group received an additional five-hour group discussion about suicide risk assessment skills. Using a case vignette, the nurses discussed and assessed suicide risk factors specified in a 10-item Chinese SAD PERSONS Scale during a group discussion intervention. The findings revealed that the nurses achieved significant and consistent improvements of risk identification and assessment after the intervention without influencing their mental health status for assessing suicide risks. The result suggested an effective approach of interactive group discussion for facilitating critical thinking and learning suicide risk assessment skills among general nurses. Copyright © 2014 Elsevier Ltd. All rights reserved.

A facility specialist model for improving retention of nursing home staff: results from a randomized, controlled study.

PubMed

Pillemer, Karl; Meador, Rhoda; Henderson, Charles; Robison, Julie; Hegeman, Carol; Graham, Edwin; Schultz, Leslie

2008-07-01

This article reports on a randomized, controlled intervention study designed to reduce employee turnover by creating a retention specialist position in nursing homes. We collected data three times over a 1-year period in 30 nursing homes, sampled in stratified random manner from facilities in New York State and Connecticut and randomly assigned to treatment and control conditions. Staff outcomes were measured through certified nursing assistant interviews, and turnover rates were measured over the course of the year. In the intervention condition, a staff member was selected to be the facility retention specialist, who would advocate for and implement programs to improve staff retention and commitment throughout the facility. Retention specialists received an intensive 3-day training in retention leadership and in a number of evidence-based retention programs. Ongoing support was provided throughout the project. Treatment facilities experienced significant declines in turnover rates compared to control facilities. As predicted, we found positive effects on certified nursing assistant assessments of the quality of retention efforts and of care provided in the facility; we did not find effects for job satisfaction or stress. The study provides evidence for the effectiveness of the retention specialist model. Findings from a detailed process evaluation suggest modifications of the program that may increase program effects.

Development of a diagnostic test set to assess agreement in breast pathology: practical application of the Guidelines for Reporting Reliability and Agreement Studies (GRRAS).

PubMed

Oster, Natalia V; Carney, Patricia A; Allison, Kimberly H; Weaver, Donald L; Reisch, Lisa M; Longton, Gary; Onega, Tracy; Pepe, Margaret; Geller, Berta M; Nelson, Heidi D; Ross, Tyler R; Tosteson, Aanna N A; Elmore, Joann G

2013-02-05

Diagnostic test sets are a valuable research tool that contributes importantly to the validity and reliability of studies that assess agreement in breast pathology. In order to fully understand the strengths and weaknesses of any agreement and reliability study, however, the methods should be fully reported. In this paper we provide a step-by-step description of the methods used to create four complex test sets for a study of diagnostic agreement among pathologists interpreting breast biopsy specimens. We use the newly developed Guidelines for Reporting Reliability and Agreement Studies (GRRAS) as a basis to report these methods. Breast tissue biopsies were selected from the National Cancer Institute-funded Breast Cancer Surveillance Consortium sites. We used a random sampling stratified according to woman's age (40-49 vs. ≥50), parenchymal breast density (low vs. high) and interpretation of the original pathologist. A 3-member panel of expert breast pathologists first independently interpreted each case using five primary diagnostic categories (non-proliferative changes, proliferative changes without atypia, atypical ductal hyperplasia, ductal carcinoma in situ, and invasive carcinoma). When the experts did not unanimously agree on a case diagnosis a modified Delphi method was used to determine the reference standard consensus diagnosis. The final test cases were stratified and randomly assigned into one of four unique test sets. We found GRRAS recommendations to be very useful in reporting diagnostic test set development and recommend inclusion of two additional criteria: 1) characterizing the study population and 2) describing the methods for reference diagnosis, when applicable.

Welfare, maternal work, and on-time childhood vaccination rates.

PubMed

Sohn, Min-Woong; Yoo, Joan; Oh, Elissa H; Amsden, Laura B; Holl, Jane L

2011-12-01

To examine effects of Temporary Assistance for Needy Families welfare cash assistance and maternal work requirements on "on-time" childhood vaccination rates. A stratified random sample of Illinois children from low-income families affected by welfare reform was monitored from 1997 to 2004. Medical records from pediatricians' offices and Medicaid claims data were used to identify the timeliness of 18 recommended vaccinations. Random-intercept logistic models were used to estimate on-time vaccine administration as a function of welfare receipt and maternal work with adjustment for characteristics of the children and mothers and time-varying covariates pertaining to the administration window for each recommended vaccine dose. Of all recommended vaccinations, 55.9% were administered on time. On-time vaccination rates were higher when families were receiving welfare than not (57.4% vs 52.8%). Children in families that either were receiving welfare or had working mothers were 1.7 to 2.1 times more likely to receive vaccinations on time compared with children in families that were not receiving welfare and did not have working mothers. When vaccine doses were stratified according to welfare status, maternal work was associated with decreased on-time vaccination rates (odds ratio: 0.73 [95% confidence interval: 0.59-0.90]) when families received welfare but increased on-time vaccination rates (odds ratio: 1.68 [95% confidence interval: 1.27-2.22]) when they did not receive welfare. These results indicate that maternal work requirements of Temporary Assistance for Needy Families had negative effects on timely administration of childhood vaccinations, although receipt of welfare itself was associated with increased on-time rates.

Prevalence of alcohol-impaired drivers based on random breath tests in a roadside survey in Catalonia (Spain).

PubMed

Alcañiz, Manuela; Guillén, Montserrat; Santolino, Miguel; Sánchez-Moscona, Daniel; Llatje, Oscar; Ramon, Lluís

2014-04-01

Sobriety checkpoints are not usually randomly located by traffic authorities. As such, information provided by non-random alcohol tests cannot be used to infer the characteristics of the general driving population. In this paper a case study is presented in which the prevalence of alcohol-impaired driving is estimated for the general population of drivers. A stratified probabilistic sample was designed to represent vehicles circulating in non-urban areas of Catalonia (Spain), a region characterized by its complex transportation network and dense traffic around the metropolis of Barcelona. Random breath alcohol concentration tests were performed during spring 2012 on 7596 drivers. The estimated prevalence of alcohol-impaired drivers was 1.29%, which is roughly a third of the rate obtained in non-random tests. Higher rates were found on weekends (1.90% on Saturdays and 4.29% on Sundays) and especially at night. The rate is higher for men (1.45%) than for women (0.64%) and it shows an increasing pattern with age. In vehicles with two occupants, the proportion of alcohol-impaired drivers is estimated at 2.62%, but when the driver was alone the rate drops to 0.84%, which might reflect the socialization of drinking habits. The results are compared with outcomes in previous surveys, showing a decreasing trend in the prevalence of alcohol-impaired drivers over time. Copyright © 2014 Elsevier Ltd. All rights reserved.

Design and methods of the Midwest Stream Quality Assessment (MSQA), 2013

USGS Publications Warehouse

Garrett, Jessica D.; Frey, Jeffrey W.; Van Metre, Peter C.; Journey, Celeste A.; Nakagaki, Naomi; Button, Daniel T.; Nowell, Lisa H.

2017-10-18

During 2013, the U.S. Geological Survey (USGS) National Water-Quality Assessment Project (NAWQA), in collaboration with the USGS Columbia Environmental Research Center, the U.S. Environmental Protection Agency (EPA) National Rivers and Streams Assessment (NRSA), and the EPA Office of Pesticide Programs assessed stream quality across the Midwestern United States. This Midwest Stream Quality Assessment (MSQA) simultaneously characterized watershed and stream-reach water-quality stressors along with instream biological conditions, to better understand regional stressor-effects relations. The MSQA design focused on effects from the widespread agriculture in the region and urban development because of their importance as ecological stressors of particular concern to Midwest region resource managers.A combined random stratified selection and a targeted selection based on land-use data were used to identify and select sites representing gradients in agricultural intensity across the region. During a 14-week period from May through August 2013, 100 sites were selected and sampled 12 times for contaminants, nutrients, and sediment. This 14-week water-quality “index” period culminated with an ecological survey of habitat, periphyton, benthic macroinvertebrates, and fish at all sites. Sediment was collected during the ecological survey for analysis of sediment chemistry and toxicity testing. Of the 100 sites, 50 were selected for the MSQA random stratified group from 154 NRSA sites planned for the region, and the other 50 MSQA sites were selected as targeted sites to more evenly cover agricultural and urban stressor gradients in the study area. Of the 50 targeted sites, 12 were in urbanized watersheds and 21 represented “good” biological conditions or “least disturbed” conditions. The remaining 17 targeted sites were selected to improve coverage of the agricultural intensity gradient or because of historical data collection to provide temporal context for the study.This report provides a detailed description of the MSQA study components, including surveys of ecological conditions, routine water sampling, deployment of passive polar organic compound integrative samplers, and stream sediment sampling at all sites. Component studies that were completed to provide finer scale temporal data or more extensive analysis at selected sites, included continuous water-quality monitoring, daily pesticide sampling, laboratory and in-stream water toxicity testing efforts, and deployment of passive suspended-sediment samplers.

The Prevalence of Four Types of Childhood Maltreatment in Denmark

PubMed Central

Christoffersen, Mogens N; Armour, Cherie; Lasgaard, Mathias; Andersen, Tonny E; Elklit, Ask

2013-01-01

Objectives: To estimate the prevalence of four types of childhood maltreatment in Denmark while taking into considerations how each of the types of maltreatment vary as a function of gender or child-protection status. Methods: Data were collected from a Danish national study conducted by The Danish National Centre for Social Research in 2008 and 2009. The study used a stratified random probability sample of young people aged 24 years. A sample of 4718 young adults were randomly selected by Statistics Denmark using the total birth cohort of all children born in 1984. The response rate was 63% leaving a total effective sample size of 2980. A structured residential or telephone interview enquired about a range of respondents maltreatment experiences. Results: Maltreatment is experienced by a significant proportion of Danish children. The reported prevalence rates were; physical neglect (3.0%), emotional abuse (5.2%), physical abuse (5.4%) and sexual abuse (3.4%). All trauma types were experienced by a greater percentage of females compared to males with the exception of physical abuse and all trauma types were experienced by a greater percentage of children given child-protection status. Conclusions: Female children and children who are given child protection status are those most at risk for experiencing maltreatment in Denmark. However, variability in prevalence rates of maltreatment across studies is problematic. Methodological variations and variation in abuse definitions may be partly attributable. PMID:24155769

Mental hospital depopulation in Canada: patient perspectives.

PubMed

Herman, N J; Smith, C M

1989-06-01

This paper reviews briefly the history of mental health depopulation in Canada over the past 30 years. The term "deinstitutionalization" is often used but is unsatisfactory. Using an exploratory, qualitative, methodological approach, data were collected on the problems encountered by a disproportionate, stratified random sample of 139 formerly institutionalized patients living in various geographical locales in Eastern Canada. Adopting a symbolic interactionist theoretical approach, this study, in an effort to fill a neglect in the literature, attempted to discover what the everyday world(s) of Canadian ex-mental patients was really like. Problems encountered related to stigma, poor housing, lack of back living skills, poverty, unemployment and aftercare. Quotations from patients are provided to illustrate such themes. The findings are discussed.

Patients' Care Needs: Documentation Analysis in General Hospitals.

PubMed

Paans, Wolter; Müller-Staub, Maria

2015-10-01

The purpose of the study is (a) to describe care needs derived from records of patients in Dutch hospitals, and (b) to evaluate whether nurses employed the NANDA-I classification to formulate patients' care needs. A stratified cross-sectional random-sampling nursing documentation audit was conducted employing the D-Catch instrument in 10 hospitals comprising 37 wards. The most prevalent nursing diagnoses were acute pain, nausea, fatigue, and risk for impaired skin integrity. Most care needs were determined in physiological health patterns and few in psychosocial patterns. To perform effective interventions leading to high-quality nursing-sensitive outcomes, nurses should also diagnose patients' care needs in the health management, value-belief, and coping stress patterns. © 2014 NANDA International, Inc.

Data survey on the effect of product features on competitive advantage of selected firms in Nigeria.

PubMed

Olokundun, Maxwell; Iyiola, Oladele; Ibidunni, Stephen; Falola, Hezekiah; Salau, Odunayo; Amaihian, Augusta; Peter, Fred; Borishade, Taiye

2018-06-01

The main objective of this study was to present a data article that investigates the effect product features on firm's competitive advantage. Few studies have examined how the features of a product could help in driving the competitive advantage of a firm. Descriptive research method was used. Statistical Package for Social Sciences (SPSS 22) was engaged for analysis of one hundred and fifty (150) valid questionnaire which were completed by small business owners registered under small and medium scale enterprises development of Nigeria (SMEDAN). Stratified and simple random sampling techniques were employed; reliability and validity procedures were also confirmed. The field data set is made publicly available to enable critical or extended analysis.

Profile of mathematical reasoning ability of 8th grade students seen from communicational ability, basic skills, connection, and logical thinking

NASA Astrophysics Data System (ADS)

Sumarsih; Budiyono; Indriati, D.

2018-04-01

This research aims to understand the students’ weaknesses in mathematical reasoning ability in junior secondary school. A set of multiple choice tests were used to measure this ability involve components mathematical communication, basic skills, connection, and logical thinking. A total of 259 respondents were determined by stratified cluster random sampling. Data were analyzed using one-way Anova test with Fobs = 109.5760 and F = 3.0000. The results show that students’ ability from schools with high National Exam in mathematics category was the best and followed by medium and low category. Mathematical connection is the most difficult component performed by students. In addition, most students also have difficulty in expressing ideas and developing logical arguments.

Research review: the effect of barriers to communication on job satisfaction and perceived work productivity.

PubMed

Rudman, W J; Gumbita, L

1995-05-01

The article describes a study that examined the effects of communication barriers on job satisfaction and perceived work productivity. Data for this study were collected from a stratified random sample of health information management professionals (n = 237). In general, supervisors and employees had similar responses on all three measures. Both supervisors and employees focused on defensiveness and personality conflicts as important barriers to communication, personal satisfaction with work and job pride as the most satisfying elements of their work, and control over the work environment as the least satisfying work condition. Also in general, personality conflicts among workers and lack of organizational skills had the strongest effects on job satisfaction and perceived work productivity.

Improving the accuracy of livestock distribution estimates through spatial interpolation.

PubMed

Bryssinckx, Ward; Ducheyne, Els; Muhwezi, Bernard; Godfrey, Sunday; Mintiens, Koen; Leirs, Herwig; Hendrickx, Guy

2012-11-01

Animal distribution maps serve many purposes such as estimating transmission risk of zoonotic pathogens to both animals and humans. The reliability and usability of such maps is highly dependent on the quality of the input data. However, decisions on how to perform livestock surveys are often based on previous work without considering possible consequences. A better understanding of the impact of using different sample designs and processing steps on the accuracy of livestock distribution estimates was acquired through iterative experiments using detailed survey. The importance of sample size, sample design and aggregation is demonstrated and spatial interpolation is presented as a potential way to improve cattle number estimates. As expected, results show that an increasing sample size increased the precision of cattle number estimates but these improvements were mainly seen when the initial sample size was relatively low (e.g. a median relative error decrease of 0.04% per sampled parish for sample sizes below 500 parishes). For higher sample sizes, the added value of further increasing the number of samples declined rapidly (e.g. a median relative error decrease of 0.01% per sampled parish for sample sizes above 500 parishes. When a two-stage stratified sample design was applied to yield more evenly distributed samples, accuracy levels were higher for low sample densities and stabilised at lower sample sizes compared to one-stage stratified sampling. Aggregating the resulting cattle number estimates yielded significantly more accurate results because of averaging under- and over-estimates (e.g. when aggregating cattle number estimates from subcounty to district level, P <0.009 based on a sample of 2,077 parishes using one-stage stratified samples). During aggregation, area-weighted mean values were assigned to higher administrative unit levels. However, when this step is preceded by a spatial interpolation to fill in missing values in non-sampled areas, accuracy is improved remarkably. This counts especially for low sample sizes and spatially even distributed samples (e.g. P <0.001 for a sample of 170 parishes using one-stage stratified sampling and aggregation on district level). Whether the same observations apply on a lower spatial scale should be further investigated.

Randomized Trial of a Gatekeeper Program for Suicide Prevention: 1-year Impact on Secondary School Staff

PubMed Central

Wyman, Peter A.; Brown, C Hendricks; Inman, Jeff; Cross, Wendi; Schmeelk-Cone, Karen; Guo, Jing; Pena, Juan B.

2009-01-01

Gatekeeper-training programs, designed to increase identification and referral of suicidal individuals, are widespread but largely untested. A group-based randomized trial with 32 schools examined impact of QPR (Question, Persuade, Refer) training on a stratified random sample of 249 staff with one-year average follow-up. To test QPR impact, we introduced and contrasted two models of gatekeeper-training effects in a population: Gatekeeper Surveillance and Gatekeeper Communication. Intent-to-treat analyses showed that training increased self-reported knowledge (ES 0.41) and appraisals of efficacy (ES 1.22) and service access (ES 1.07). Training effects varied dramatically. Appraisals increased most for staff with lowest baseline appraisals, and suicide identification behaviors increased most for staff already communicating with students about suicide and distress. Consistent with the Communication model, increased knowledge and appraisals were not sufficient to increase suicide identification behaviors. Also consistent with the Communication model were results from 2,059 8th and 10th graders surveyed showing that fewer with prior suicide attempts endorsed talking to adults about distress. Skill training for staff serving as ‘natural-gatekeepers’ plus interventions that modify students’ help-seeking behaviors are recommended to supplement universal gatekeeper training. PMID:18229988

Randomization in clinical trials in orthodontics: its significance in research design and methods to achieve it.

PubMed

Pandis, Nikolaos; Polychronopoulou, Argy; Eliades, Theodore

2011-12-01

Randomization is a key step in reducing selection bias during the treatment allocation phase in randomized clinical trials. The process of randomization follows specific steps, which include generation of the randomization list, allocation concealment, and implementation of randomization. The phenomenon in the dental and orthodontic literature of characterizing treatment allocation as random is frequent; however, often the randomization procedures followed are not appropriate. Randomization methods assign, at random, treatment to the trial arms without foreknowledge of allocation by either the participants or the investigators thus reducing selection bias. Randomization entails generation of random allocation, allocation concealment, and the actual methodology of implementing treatment allocation randomly and unpredictably. Most popular randomization methods include some form of restricted and/or stratified randomization. This article introduces the reasons, which make randomization an integral part of solid clinical trial methodology, and presents the main randomization schemes applicable to clinical trials in orthodontics.

Fitting parametric random effects models in very large data sets with application to VHA national data

PubMed Central

2012-01-01

Background With the current focus on personalized medicine, patient/subject level inference is often of key interest in translational research. As a result, random effects models (REM) are becoming popular for patient level inference. However, for very large data sets that are characterized by large sample size, it can be difficult to fit REM using commonly available statistical software such as SAS since they require inordinate amounts of computer time and memory allocations beyond what are available preventing model convergence. For example, in a retrospective cohort study of over 800,000 Veterans with type 2 diabetes with longitudinal data over 5 years, fitting REM via generalized linear mixed modeling using currently available standard procedures in SAS (e.g. PROC GLIMMIX) was very difficult and same problems exist in Stata’s gllamm or R’s lme packages. Thus, this study proposes and assesses the performance of a meta regression approach and makes comparison with methods based on sampling of the full data. Data We use both simulated and real data from a national cohort of Veterans with type 2 diabetes (n=890,394) which was created by linking multiple patient and administrative files resulting in a cohort with longitudinal data collected over 5 years. Methods and results The outcome of interest was mean annual HbA1c measured over a 5 years period. Using this outcome, we compared parameter estimates from the proposed random effects meta regression (REMR) with estimates based on simple random sampling and VISN (Veterans Integrated Service Networks) based stratified sampling of the full data. Our results indicate that REMR provides parameter estimates that are less likely to be biased with tighter confidence intervals when the VISN level estimates are homogenous. Conclusion When the interest is to fit REM in repeated measures data with very large sample size, REMR can be used as a good alternative. It leads to reasonable inference for both Gaussian and non-Gaussian responses if parameter estimates are homogeneous across VISNs. PMID:23095325

Crime Victimization in Adults With Severe Mental Illness

PubMed Central

Teplin, Linda A.; McClelland, Gary M.; Abram, Karen M.; Weiner, Dana A.

2006-01-01

Context Since deinstitutionalization, most persons with severe mental illness (SMI) now live in the community, where they are at great risk for crime victimization. Objectives To determine the prevalence and incidence of crime victimization among persons with SMI by sex, race/ethnicity, and age, and to compare rates with general population data (the National Crime Victimization Survey), controlling for income and demographic differences between the samples. Design Epidemiologic study of persons in treatment. Independent master’s-level clinical research interviewers administered the National Crime Victimization Survey to randomly selected patients sampled from 16 randomly selected mental health agencies. Setting Sixteen agencies providing outpatient, day, and residential treatment to persons with SMI in Chicago, Ill. Participants Randomly selected, stratified sample of 936 patients aged 18 or older (483 men, 453 women) who were African American (n = 329), non-Hispanic white (n = 321), Hispanic (n = 270), or other race/ethnicity (n = 22). The comparison group comprised 32449 participants in the National Crime Victimization Survey. Main Outcome Measure National Crime Victimization Survey, developed by the Bureau of Justice Statistics. Results More than one quarter of persons with SMI had been victims of a violent crime in the past year, a rate more than 11 times higher than the general population rates even after controlling for demographic differences between the 2 samples (P<.001). The annual incidence of violent crime in the SMI sample (168.2 incidents per 1000 persons) is more than 4 times higher than the general population rates (39.9 incidents per 1000 persons) (P<.001). Depending on the type of violent crime (rape/sexual assault, robbery, assault, and their subcategories), prevalence was 6 to 23 times greater among persons with SMI than among the general population. Conclusions Crime victimization is a major public health problem among persons with SMI who are treated in the community. We recommend directions for future research, propose modifications in public policy, and suggest how the mental health system can respond to reduce victimization and its consequences. PMID:16061769

Crime victimization in adults with severe mental illness: comparison with the National Crime Victimization Survey.

PubMed

Teplin, Linda A; McClelland, Gary M; Abram, Karen M; Weiner, Dana A

2005-08-01

Since deinstitutionalization, most persons with severe mental illness (SMI) now live in the community, where they are at great risk for crime victimization. To determine the prevalence and incidence of crime victimization among persons with SMI by sex, race/ethnicity, and age, and to compare rates with general population data (the National Crime Victimization Survey), controlling for income and demographic differences between the samples. Epidemiologic study of persons in treatment. Independent master's-level clinical research interviewers administered the National Crime Victimization Survey to randomly selected patients sampled from 16 randomly selected mental health agencies. Sixteen agencies providing outpatient, day, and residential treatment to persons with SMI in Chicago, Ill. Randomly selected, stratified sample of 936 patients aged 18 or older (483 men, 453 women) who were African American (n = 329), non-Hispanic white (n = 321), Hispanic (n = 270), or other race/ethnicity (n = 22). The comparison group comprised 32 449 participants in the National Crime Victimization Survey. National Crime Victimization Survey, developed by the Bureau of Justice Statistics. More than one quarter of persons with SMI had been victims of a violent crime in the past year, a rate more than 11 times higher than the general population rates even after controlling for demographic differences between the 2 samples (P<.001). The annual incidence of violent crime in the SMI sample (168.2 incidents per 1000 persons) is more than 4 times higher than the general population rates (39.9 incidents per 1000 persons) (P<.001). Depending on the type of violent crime (rape/sexual assault, robbery, assault, and their subcategories), prevalence was 6 to 23 times greater among persons with SMI than among the general population. Crime victimization is a major public health problem among persons with SMI who are treated in the community. We recommend directions for future research, propose modifications in public policy, and suggest how the mental health system can respond to reduce victimization and its consequences.

Local Environmental Factors Drive Divergent Grassland Soil Bacterial Communities in the Western Swiss Alps.

PubMed

Yashiro, Erika; Pinto-Figueroa, Eric; Buri, Aline; Spangenberg, Jorge E; Adatte, Thierry; Niculita-Hirzel, Hélène; Guisan, Antoine; van der Meer, Jan Roelof

2016-11-01

Mountain ecosystems are characterized by a diverse range of climatic and topographic conditions over short distances and are known to shelter a high biodiversity. Despite important progress, still little is known on bacterial diversity in mountain areas. Here, we investigated soil bacterial biogeography at more than 100 sampling sites randomly stratified across a 700-km 2 area with 2,200-m elevation gradient in the western Swiss Alps. Bacterial grassland communities were highly diverse, with 12,741 total operational taxonomic units (OTUs) across 100 sites and an average of 2,918 OTUs per site. Bacterial community structure was correlated with local climatic, topographic, and soil physicochemical parameters with high statistical significance. We found pH (correlated with % CaO and % mineral carbon), hydrogen index (correlated with bulk gravimetric water content), and annual average number of frost days during the growing season to be among the groups of the most important environmental drivers of bacterial community structure. In contrast, bacterial community structure was only weakly stratified as a function of elevation. Contrasting patterns were discovered for individual bacterial taxa. Acidobacteria responded both positively and negatively to pH extremes. Various families within the Bacteroidetes responded to available phosphorus levels. Different verrucomicrobial groups responded to electrical conductivity, total organic carbon, water content, and mineral carbon contents. Alpine grassland bacterial communities are thus highly diverse, which is likely due to the large variety of different environmental conditions. These results shed new light on the biodiversity of mountain ecosystems, which were already identified as potentially fragile to anthropogenic influences and climate change. This article addresses the question of how microbial communities in alpine regions are dependent on local climatic and soil physicochemical variables. We benefit from a unique 700-km 2 study region in the western Swiss Alps region, which has been exhaustively studied for macro-organismal and fungal ecology, and for topoclimatic modeling of future ecological trends, but without taking into account soil bacterial diversity. Here, we present an in-depth biogeographical characterization of the bacterial community diversity in this alpine region across 100 randomly stratified sites, using 56 environmental variables. Our exhaustive sampling ensured the detection of ecological trends with high statistical robustness. Our data both confirm previously observed general trends and show many new detailed trends for a wide range of bacterial taxonomic groups and environmental parameters. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Associations of School Connectedness With Adolescent Suicidality: Gender Differences and the Role of Risk of Depression

PubMed Central

Langille, Donald B; Asbridge, Mark; Cragg, Amber; Rasic, Daniel

2015-01-01

Objective: Previous studies have not examined associations of school connectedness with adolescent suicidal behaviours stratified by gender, while including a measure of depression. We analyzed survey data to determine whether there are independent protective associations of higher school connectedness with suicidal behaviours in Canadian adolescents, while controlling for potential confounders, including risk of depression; and whether such associations differ by gender. Method: Using data from a stratified cluster sample of randomly selected classes of students in schools in 3 of Canada’s Atlantic provinces, we used multiple logistic regression to examine whether associations of risk of depression, measured using the 12-item Center for Epidemiologic Studies–Depression scale, lessened protective associations of higher school connectedness with suicidal behaviours in grades 10 and 12 students, while stratifying by gender. Results: After adjusting for risk of depression, higher school connectedness was independently associated with decreased suicidal ideation in both genders and with suicidal attempt in females. In males, higher connectedness was no longer protective for suicide attempt when risk of depression was included in the model. Conclusions: School connectedness, which is felt to have positive influences on many types of adolescent behaviour, appears to also be both directly and indirectly protective for suicidality. These effects may occur through different pathways in females and males. Given the protection it offers both genders, including those at risk and not at risk of depression, increasing school connectedness should be considered as a universal adolescent mental health strategy. Studies that examine school connectedness should include analyses that examine potential differences between males and females. PMID:26175323

Cognitive function and dementia in six areas of England and Wales: the distribution of MMSE and prevalence of GMS organicity level in the MRC CFA Study. The Medical Research Council Cognitive Function and Ageing Study (MRC CFAS).

PubMed

1998-03-01

This two-stage prevalence survey involved geographically delimited areas, four urban (Liverpool, Newcastle, Nottingham and Oxford) and two rural (Cambridgeshire and Gwynedd), including institutions. Stratified random population samples of people in their 65th year and above, from Family Health Service Authorities were studied. The sample was stratified (65-74 years and > or = 75) to provide equal numbers. In Liverpool equal numbers in 5 year age groups were taken. After an initial screening interview, approximately 20% were selected on the basis of age, AGECAT organicity confidence level and MMSE score to proceed to a detailed assessment interview from which the full AGECAT organicity confidence level could be derived. Major influences on MMSE were confirmed as age, sex, social class and educational level. Estimates of prevalence of AGECAT O3 and above for each centre and the entire sample according to age are given, based on 1991 Census population structure, and suggest that around half a million (543,400) people in England and Wales would be defined as case level by this method. The five centres employing the same methodology showed no heterogeneity in prevalence. Prevalence of cognitive impairment and dementia appear not to vary widely across the centres examined in this study, which provides stable estimates by age and sex for AGECAT O3 and above, and norms for MMSE. Using these estimates as an indication of the size of the population affected, around 550,000 individuals in England and Wales would be expected to be suffering from dementia of mild or greater severity.

Maternal prenatal cortisol predicts infant negative emotionality in a sex-dependent manner.

PubMed

Braithwaite, Elizabeth C; Pickles, Andrew; Sharp, Helen; Glover, Vivette; O'Donnell, Kieran J; Tibu, Florin; Hill, Jonathan

2017-06-01

Prenatal stress influences fetal developmental trajectories, which may implicate glucocorticoid mechanisms. There is also emerging evidence that effects of prenatal stress on offspring development are sex-dependent. However, little is known about the prospective relationship between maternal prenatal cortisol levels and infant behaviour, and whether it may be different in male and female infants. We sought to address this question using data from a prospective longitudinal cohort, stratified by risk. The Wirral Child Health and Development Study (WCHADS) cohort (n=1233) included a stratified random sub-sample (n=216) who provided maternal saliva samples, assayed for cortisol, at home over two days at 32weeks of pregnancy (on waking, 30-min post-waking and during the evening) and a measure of infant negative emotionality from the Neonatal Behavioural Assessment Scale (NBAS) at five weeks-of-age. General population estimates of associations among measures were obtained using inverse probability weights. Maternal prenatal cortisol sampled on waking predicted infant negative emotionality in a sex-dependent manner (interaction term, p=0.005); female infants exposed to high levels of prenatal cortisol were more negative (Beta=0.440, p=0.042), whereas male infants were less negative (Beta=-0.407, p=0.045). There was no effect of the 30-min post-waking measure or evening cortisol. Our findings add to an emerging body of work that has highlighted sex differences in fetal programming, whereby females become more reactive following prenatal stress, and males less reactive. A more complete understanding of sex-specific developmental trajectories in the context of prenatal stress is essential for the development of targeted prevention strategies. Copyright © 2017. Published by Elsevier Inc.

The prevalence of depressive symptoms among adolescents in Nairobi public secondary schools: association with perceived maladaptive parental behaviour.

PubMed

Khasakhala, L I; Ndetei, D M; Mutiso, V; Mbwayo, A W; Mathai, M

2012-03-01

Depression in adolescents is a matter of concern because of its high prevalence, potential recurrence and impairment of functioning in the affected individual. The study sought to determine the prevalence of depressive symptoms among adolescents in Nairobi (Kenya) public secondary schools; make a comparison between day and boarding students; and identify associated factors in this population. A random sample of school going adolescents was taken from a stratified sample of 17 secondary schools out of the 49 public secondary schools in Nairobi province. The sample was stratified to take into account geographical distribution, day and boarding schools, boys only, girls only and mixed (co-education) schools in the capital city of Kenya. Self administered instruments (EMBU and CDI) were used to measure perceived parental behaviour and levels of depression in a total of 1,276 students excluding those who had no living parent. The prevalence of clinically significant depressive symptoms was 26.4%. The occurrence was higher in girls than it was in boys p<0.001. Students in boarding schools had more clinically significant depressive symptoms compared to day students (p=0.01). More girls exhibited suicidal behaviour than boys (p<0.001). There was a significant correlation between depressive symptoms and suicidal behaviour (p<0.001). CDI scores correlated positively with age (p<0.001) with an increase in CDI score with unit increase in age among students 14-17 years old, perceived rejecting maternal parenting behaviour (p<0.001), perceived no emotional attachment paternal behaviour (p<0.001), perceived no emotional attachment maternal behaviour (p<0.001), and perceived under protective paternal behaviour (p=0.005). Perceived maladaptive parental behaviours are substantially associated with the development of depressive symptoms and suicidal behaviour in children.

Characteristics and Course of Heart Failure Stages A-B and Determinants of Progression - design and rationale of the STAAB cohort study.

PubMed

Wagner, Martin; Tiffe, Theresa; Morbach, Caroline; Gelbrich, Götz; Störk, Stefan; Heuschmann, Peter U

2017-03-01

Background Data from the general population on the natural course of heart failure is lacking. The objectives of the STAAB cohort study are to determine the prevalence of heart failure stages A-B in a representative sample of the general population and to prospectively investigate the progression from asymptomatic cardiac dysfunction into symptomatic heart failure. Here we present study design, participation rates and baseline characteristics of the first 1468 enrolled subjects. Methods A random sample of inhabitants from the city of Würzburg stratified by age (30-79 years) and gender was drawn from the local registration office. Subjects receive invitation letters, while send-out batches are continuously adapted to response rates by age and gender. At baseline examination, data on echocardiographic cardiac function, comorbidities and preclinical cardiovascular phenotypes are collected. After 3-5 years, changes in cardiac function and occurrence of clinical events will be assessed in a follow-up visit. Results Between December 2013 and April 2015, 4499 subjects were invited; of those, 1510 (34.6%) responded positively, and 1468 were examined (32.6%). Stratified recruitment was on-target while the participation rate was highest in subjects aged 60-69 years (38%). Hypertension (42%) and dyslipidaemia (37%) were the most commonly reported comorbidities; 7% reported on diabetes and 23% of men ( vs. 17% of women) were smokers. Conclusions STAAB recruits a representative population-based sample suited to provide reliable estimates of the frequency of asymptomatic cardiac dysfunction and determinants of disease progression into symptomatic heart failure. These findings will build the ground for developing preventive strategies for heart failure at different stages of the disease continuum.

[Prevalence and risk factors of bronchial asthma among Li nationality in Hainan province].

PubMed

Ding, Yi-peng; Yao, Hong-xia; Tang, Xiao-lan; He, Hai-wu; Shi, Hui-fang; Lin, Li; Li, Min; Chen, Shan; Chen, Jing; Wang, Hai-jiao

2011-02-01

To study the risk factors of bronchial asthma of Li nationality in Hainan. A total of 13 050 subjects of Li nationality were selected by random unequal ratio stratified cluster sampling method from southern, central and western part of Hainan and investigated with Hainan Epidemiological Asthma Survey Questionnaire of Li Nationality. There were 441 cases of bronchial asthma, and 1296 cases of control that were sampled by random number table method. The logistic regression method was used to analyze risk factors. The asthma prevalence of Li nationality in Hainan was 3.38%(441/13 050). The main risk factors of asthma were family asthma (OR = 4.323, 95%CI = 3.259 - 5.735), hypersensitiveness (OR = 7.775, 95%CI = 5.686 - 10.632), smoking (OR = 1.494, 95%CI = 1.174 - 1.902), cooking fuels and living environment. Cold air change (OR = 1.604, 95%CI = 1.286 - 2.001) and respirable dust or irritant gas (OR = 2.123, 95%CI = 1.702 - 2.648) were the important incentives. The main risk factors of asthma among Li nationality were family asthma, hypersensitiveness, smoking, cooking fuels by means of fuel oil, hay or wood, living environment by means of couch grass room and human-livestock mix live, cold air change, respirable dust or irritant gas.

Socioeconomic status and weight control practices in British adults

PubMed Central

Wardle, J; Griffith, J

2001-01-01

STUDY OBJECTIVE—Attitudes and practices concerning weight control in British adults were examined to test the hypothesis that variation in concern about weight and deliberate weight control might partly explain the socioeconomic status (SES) gradient in obesity. Higher SES groups were hypothesised to show more weight concern and higher levels of dieting.
SETTING—Data were collected as part of the monthly Omnibus Survey of the Office of National Statistics in March 1999.
PARTICIPANTS—A stratified, probability sample of 2690 households was selected by random sampling of addresses in Britain. One randomly selected person in each household was interviewed at their home.
MAIN RESULTS—As predicted, higher SES men and women had higher levels of perceived overweight, monitored their weight more closely, and were more likely to be trying to lose weight. Higher SES groups also reported more restrictive dietary practices and more vigorous physical activity.
CONCLUSIONS—The results are consistent with the idea that part of the protection against weight gain in higher SES groups could be a higher frequency of weight monitoring, a lower threshold for defining themselves as overweight, and a greater likelihood of deliberate efforts at weight control.


Keywords: socioeconomic status; weight control; obesity PMID:11160173

Assessing map accuracy in a remotely sensed, ecoregion-scale cover map

USGS Publications Warehouse

Edwards, T.C.; Moisen, Gretchen G.; Cutler, D.R.

1998-01-01

Landscape- and ecoregion-based conservation efforts increasingly use a spatial component to organize data for analysis and interpretation. A challenge particular to remotely sensed cover maps generated from these efforts is how best to assess the accuracy of the cover maps, especially when they can exceed 1000 s/km2 in size. Here we develop and describe a methodological approach for assessing the accuracy of large-area cover maps, using as a test case the 21.9 million ha cover map developed for Utah Gap Analysis. As part of our design process, we first reviewed the effect of intracluster correlation and a simple cost function on the relative efficiency of cluster sample designs to simple random designs. Our design ultimately combined clustered and subsampled field data stratified by ecological modeling unit and accessibility (hereafter a mixed design). We next outline estimation formulas for simple map accuracy measures under our mixed design and report results for eight major cover types and the three ecoregions mapped as part of the Utah Gap Analysis. Overall accuracy of the map was 83.2% (SE=1.4). Within ecoregions, accuracy ranged from 78.9% to 85.0%. Accuracy by cover type varied, ranging from a low of 50.4% for barren to a high of 90.6% for man modified. In addition, we examined gains in efficiency of our mixed design compared with a simple random sample approach. In regard to precision, our mixed design was more precise than a simple random design, given fixed sample costs. We close with a discussion of the logistical constraints facing attempts to assess the accuracy of large-area, remotely sensed cover maps.

Predicting the onset and persistence of episodes of depression in primary health care. The predictD-Spain study: Methodology

PubMed Central

Bellón, Juan Ángel; Moreno-Küstner, Berta; Torres-González, Francisco; Montón-Franco, Carmen; GildeGómez-Barragán, María Josefa; Sánchez-Celaya, Marta; Díaz-Barreiros, Miguel Ángel; Vicens, Catalina; de Dios Luna, Juan; Cervilla, Jorge A; Gutierrez, Blanca; Martínez-Cañavate, María Teresa; Oliván-Blázquez, Bárbara; Vázquez-Medrano, Ana; Sánchez-Artiaga, María Soledad; March, Sebastia; Motrico, Emma; Ruiz-García, Victor Manuel; Brangier-Wainberg, Paulette Renée; del Mar Muñoz-García, María; Nazareth, Irwin; King, Michael

2008-01-01

Background The effects of putative risk factors on the onset and/or persistence of depression remain unclear. We aim to develop comprehensive models to predict the onset and persistence of episodes of depression in primary care. Here we explain the general methodology of the predictD-Spain study and evaluate the reliability of the questionnaires used. Methods This is a prospective cohort study. A systematic random sample of general practice attendees aged 18 to 75 has been recruited in seven Spanish provinces. Depression is being measured with the CIDI at baseline, and at 6, 12, 24 and 36 months. A set of individual, environmental, genetic, professional and organizational risk factors are to be assessed at each follow-up point. In a separate reliability study, a proportional random sample of 401 participants completed the test-retest (251 researcher-administered and 150 self-administered) between October 2005 and February 2006. We have also checked 118,398 items for data entry from a random sample of 480 patients stratified by province. Results All items and questionnaires had good test-retest reliability for both methods of administration, except for the use of recreational drugs over the previous six months. Cronbach's alphas were good and their factorial analyses coherent for the three scales evaluated (social support from family and friends, dissatisfaction with paid work, and dissatisfaction with unpaid work). There were 191 (0.16%) data entry errors. Conclusion The items and questionnaires were reliable and data quality control was excellent. When we eventually obtain our risk index for the onset and persistence of depression, we will be able to determine the individual risk of each patient evaluated in primary health care. PMID:18657275

Determinants of serum zinc in a random population sample of four Belgian towns with different degrees of environmental exposure to cadmium

PubMed Central

Thijs, Lutgarde; Staessen, Jan; Amery, Antoon; Bruaux, Pierre; Buchet, Jean-Pierre; Claeys, FranÇoise; De Plaen, Pierre; Ducoffre, Geneviève; Lauwerys, Robert; Lijnen, Paul; Nick, Laurence; Remy, Annie Saint; Roels, Harry; Rondia, Désiré; Sartor, Francis

1992-01-01

This report investigated the distribution of serum zinc and the factors determining serum zinc concentration in a large random population sample. The 1977 participants (959 men and 1018 women), 20–80 years old, constituted a stratified random sample of the population of four Belgian districts, representing two areas with low and two with high environmental exposure to cadmium. For each exposure level, a rural and an urban area were selected. The serum concentration of zinc, frequently used as an index for zinc status in human subjects, was higher in men (13.1 μmole/L, range 6.5–23.0 μmole/L) than in women (12.6 μmole/L, range 6.3–23.2 μmole/L). In men, 20% of the variance of serum zinc was explained by age (linear and squared term, R = 0.29), diurnal variation (r = 0.29), and total cholesterol (r = 0.16). After adjustment for these covariates, a negative relationship was observed between serum zinc and both blood (r = −0.10) and urinary cadmium (r = −0.14). In women, 11% of the variance could be explained by age (linear and squared term, R = 0.15), diurnal variation in serum zinc (r = 0.27), creatinine clearance (r = −0.11), log γ-glutamyltranspeptidase (r = 0.08), cholesterol (r = 0.07), contraceptive pill intake (r = −0.07), and log serum ferritin (r = 0.06). Before and after adjustment for significant covariates, serum zinc was, on average, lowest in the two districts where the body burden of cadmium, as assessed by urinary cadmium excretion, was highest. These results were not altered when subjects exposed to heavy metals at work were excluded from analysis. PMID:1486857

Cardiovascular risk reduction intervention among school-students in Kolkata, West Bengal - the CRRIS study protocol.

PubMed

Kumar, Soumitra; Ray, Saumitra; Mahapatra, Tanmay; Gupta, Kinnari; Mahapatra, Sanchita; Das, Mrinal K; Guha, Santanu; Deb, Pradip K; Banerjee, Amal K

2015-01-01

Increasing burden of cardiovascular risk-factors among adolescent school-children is a major concern in India. Dearth of information regarding the burden of these factors and the efficacy of educational intervention in minimizing them among urban school-students of India called for a school-based, educational intervention involving a representative sample of these students and their caregivers. Using a randomized-controlled design with stratified-random sampling, 1000 students (approximately 50/school) of 9th grade from 20 randomly selected schools (representing all socio-economic classes and school-types) and their caregivers (preferably mothers) will be recruited. Objectives of the study will include: estimation of the baseline burden and post-interventional change in cardiovascular risk-factors, related knowledge, perception and practice among participants in Kolkata. After obtaining appropriate consent (assent for adolescents), collection of the questionnaire-based data (regarding cardiovascular disease/risk-factor related knowledge, perception, practice), anthropometric measurements, stress assessment and cardiological check-up (pulse and blood pressure measurement along with auscultation for any abnormal heart sounds) will be conducted for each participating students twice at an interval of six months. In between 6 educational sessions will be administered in 10 of the 20 schools randomized to the intervention arm. After the follow-up data collection, same sessions will be conducted in the non-interventional schools. Descriptive and inferential analyses (using SAS 9.3) will be conducted to determine the distribution of the risk-factors and efficacy of the intervention in minimizing them so that policy-making can be guided appropriately to keep the adolescents healthy in their future life. Copyright © 2015 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

Psychosocial working conditions and work-related stressors among UK veterinary surgeons.

PubMed

Bartram, David J; Yadegarfar, Ghasem; Baldwin, David S

2009-08-01

Anecdotally, veterinary surgeons report high levels of work-related stress. To investigate psychosocial working conditions, self-reported causes of work-related stress and satisfaction among a representative sample of vets practising in the UK. A cross-sectional study using a questionnaire mailed to a stratified random sample of 3200 vets. The Health & Safety Executive Management Standards Indicator Tool and a series of bespoke questions were embedded in a 120 item questionnaire, which also assessed anxiety and depressive symptoms, alcohol consumption, suicidal ideation, positive mental well-being and work-home interaction. A total of 1796 useable questionnaires were returned (response rate 56%). Number of hours worked and making professional mistakes were the main reported contributors to stress. Good clinical outcomes and relationships with colleagues were the greatest sources of satisfaction. Anxiety and depressive symptoms are associated with less favourable working conditions. Compared to the general population, the sample reported higher risk of work-related stress for demands and managerial support but lower risk for relationships and change. The results could be used to inform the development of targeted interventions.

The utility of point count surveys to predict wildlife interactions with wind energy facilities: An example focused on golden eagles

USGS Publications Warehouse

Sur, Maitreyi; Belthoff, James R.; Bjerre, Emily R.; Millsap, Brian A.; Katzner, Todd

2018-01-01

Wind energy development is rapidly expanding in North America, often accompanied by requirements to survey potential facility locations for existing wildlife. Within the USA, golden eagles (Aquila chrysaetos) are among the most high-profile species of birds that are at risk from wind turbines. To minimize golden eagle fatalities in areas proposed for wind development, modified point count surveys are usually conducted to estimate use by these birds. However, it is not always clear what drives variation in the relationship between on-site point count data and actual use by eagles of a wind energy project footprint. We used existing GPS-GSM telemetry data, collected at 15 min intervals from 13 golden eagles in 2012 and 2013, to explore the relationship between point count data and eagle use of an entire project footprint. To do this, we overlaid the telemetry data on hypothetical project footprints and simulated a variety of point count sampling strategies for those footprints. We compared the time an eagle was found in the sample plots with the time it was found in the project footprint using a metric we called “error due to sampling”. Error due to sampling for individual eagles appeared to be influenced by interactions between the size of the project footprint (20, 40, 90 or 180 km2) and the sampling type (random, systematic or stratified) and was greatest on 90 km2 plots. However, use of random sampling resulted in lowest error due to sampling within intermediate sized plots. In addition sampling intensity and sampling frequency both influenced the effectiveness of point count sampling. Although our work focuses on individual eagles (not the eagle populations typically surveyed in the field), our analysis shows both the utility of simulations to identify specific influences on error and also potential improvements to sampling that consider the context-specific manner that point counts are laid out on the landscape.

Incidence of non-lung solid cancers in Czech uranium miners: a case-cohort study

PubMed Central

Kulich, M.; Řeřicha, V.; Řeřicha, R.; Shore, D.L.; Sandler, D.P.

2011-01-01

Objectives Uranium miners are chronically exposed to radon and its progeny, which are known to cause lung cancer and may be associated with leukemia. This study was undertaken to evaluate risk of non-lung solid cancers among uranium miners in Příbram region, Czech Republic. Methods A retrospective stratified case-cohort study in a cohort of 22,816 underground miners who were employed between 1949 and 1975. All incident non-lung solid cancers were ascertained among miners who worked underground for at least 12 months (n = 1020). A subcohort of 1707 subjects was randomly drawn from the same population by random sampling stratified on age. The follow-up period lasted from 1977 to 1996. Results Relative risks comparing 180 WLM (90th percentile) of cumulative lifetime radon exposure to 3 WLM (10th percentile) were 0.88 for all non-lung solid cancers combined (95% CI 0.73 – 1.04, n = 1020), 0.87 for all digestive cancers (95% CI 0.69 – 1.09, n = 561), 2.39 for gallbladder cancer (95% CI 0.52 – 10.98, n = 13), 0.79 for larynx cancer (95% CI 0.38 – 1.64, n = 62), 2.92 for malignant melanoma (95% CI 0.91 – 9.42, n = 23), 0.84 for bladder cancer (95% CI 0.43 – 1.65, n = 73), and 1.13 for kidney cancer (95% CI 0.62 – 2.04, n = 66). No cancer type was significantly associated with radon exposure; only malignant melanoma and gallbladder cancer showed elevated but non-significant association with radon. Conclusions Radon was not significantly associated with incidence of any cancer of interest, although a positive association of radon with malignant melanoma and gallbladder cancer cannot be entirely ruled out. PMID:21256480

Incidence of non-lung solid cancers in Czech uranium miners: a case-cohort study.

PubMed

Kulich, M; Reřicha, V; Reřicha, R; Shore, D L; Sandler, D P

2011-04-01

Uranium miners are chronically exposed to radon and its progeny, which are known to cause lung cancer and may be associated with leukemia. This study was undertaken to evaluate risk of non-lung solid cancers among uranium miners in Příbram region, Czech Republic. A retrospective stratified case-cohort study in a cohort of 22,816 underground miners who were employed between 1949 and 1975. All incident non-lung solid cancers were ascertained among miners who worked underground for at least 12 months (n=1020). A subcohort of 1707 subjects was randomly drawn from the same population by random sampling stratified on age. The follow-up period lasted from 1977 to 1996. Relative risks comparing 180 WLM (90th percentile) of cumulative lifetime radon exposure to 3 WLM (10th percentile) were 0.88 for all non-lung solid cancers combined (95% CI 0.73-1.04, n=1020), 0.87 for all digestive cancers (95% CI 0.69-1.09, n=561), 2.39 for gallbladder cancer (95% CI 0.52-10.98, n=13), 0.79 for larynx cancer (95% CI 0.38-1.64, n=62), 2.92 for malignant melanoma (95% CI 0.91-9.42, n=23), 0.84 for bladder cancer (95% CI 0.43-1.65, n=73), and 1.13 for kidney cancer (95% CI 0.62-2.04, n=66). No cancer type was significantly associated with radon exposure; only malignant melanoma and gallbladder cancer showed elevated but non-significant association with radon. Radon was not significantly associated with incidence of any cancer of interest, although a positive association of radon with malignant melanoma and gallbladder cancer cannot be entirely ruled out. Copyright © 2011 Elsevier Inc. All rights reserved.

Patient volume, staffing, and workload in relation to risk-adjusted outcomes in a random stratified sample of UK neonatal intensive care units: a prospective evaluation.

PubMed

Tucker, Janet

2002-01-12

UK recommendations suggest that large neonatal intensive-care units (NICUs) have better outcomes than small units, although this suggestion remains unproven. We assessed whether patient volume, staffing levels, and workload are associated with risk-adjusted outcomes, and with costs or staff wellbeing. 186 UK NICUs were stratified according to volume of patients, nursing provision, and neonatal consultant provision. Primary outcomes were hospital mortality, mortality or cerebral damage, and nosocomial bacteraemia. We studied 13515 infants of all birthweights consecutively admitted to 54 randomly selected NICUs. Multiple logistic regression analyses were done with every primary outcome as the dependent variable. Staff wellbeing and stress were assessed by anonymous mental health index (MHI)-5 questionnaires. Data were available for 13334 (99%) infants. High-volume NICUs treated the sickest infants and had highest crude mortality. Risk-adjusted mortality and mortality or cerebral damage were unrelated to patient volume or staffing provision; however, nosocomial bacteraemia was less frequent in NICUs with low neonatal consultant provision (odds ratio 0.65, 95% CI 0.43-0.98). Mortality was raised with increasing workload in all types of NICUs. Infants admitted at full capacity versus half capacity were about 50% more likely to die, but there was wide uncertainty around this estimate. Most staff had MHI-5 scores that suggested good mental health. The implications of this report for staffing policy, medicolegal risk management, and ethical practice remain to be tested. Centralisation of only the sickest infants could improve efficiency, provided that this does not create excessive workload for staff. Assessment of increased staffing levels that are closer to those in adult intensive care might be appropriate.

Unmet dental needs and barriers to dental care among children with autism spectrum disorders.

PubMed

Lai, Bien; Milano, Michael; Roberts, Michael W; Hooper, Stephen R

2012-07-01

Mail-in pilot-tested questionnaires were sent to a stratified random sample of 1,500 families from the North Carolina Autism Registry. Multivariate logistic regression analysis was used to determine the significance of unmet dental needs and other predictors. Of 568 surveys returned (Response Rate = 38%), 555 were complete and usable. Sixty-five (12%) children had unmet dental needs. Of 516 children (93%) who had been to a dentist, 11% still reported unmet needs. The main barriers were child's behavior, cost, and lack of insurance. The significant predictor variables of unmet needs were child's behavior (p = 0.01), child's dental health (p < 0.001), and caregiver's last dental visit greater than 6 months (p = 0.002). Type of ASD did not have an effect on having unmet dental needs.

Welfare reform and health insurance: consequences for parents.

PubMed

Holl, Jane L; Slack, Kristen Shook; Stevens, Amy Bush

2005-02-01

We assessed the relation between the work promotion, welfare reduction, and marriage goals of welfare reform and the stability of health insurance of parents in transition from welfare to work. We analyzed a panel survey (1999-2002) of a stratified random sample of Illinois families receiving welfare in 1998 (n=1363). Medicaid remains the foremost source of health insurance despite a significant decline in the proportion of parents with Medicaid. Regardless of work/welfare status in year 1, transitioning to work only or no work/no welfare increased the likelihood of having unstable health insurance in years 2 and 3 compared with those who remained on welfare only. Parents who meet the welfare reform goals of work promotion and reduction of welfare dependence experience significant loss and instability of health insurance.

Data article on the effect of work engagement strategies on faculty staff behavioural outcomes in private universities.

PubMed

Falola, Hezekiah Olubusayo; Olokundun, Maxwell Ayodele; Salau, Odunayo Paul; Oludayo, Olumuyiwa Akinrole; Ibidunni, Ayodotun Stephen

2018-06-01

The main objective of this study was to present a data article that investigate the effect of work engagement strategies on faculty behavioural outcomes. Few studies analyse how work engagement strategies could help in driving standard work behaviour particularly in higher institutions. In an attempt to bridge this gap, this study was carried out using descriptive research method and Structural Equation Model (AMOS 22) for the analysis of four hundred and forty one (441) valid questionnaire which were completed by the faculty members of the six selected private universities in Nigeria using stratified and simple random sampling techniques. Factor model which shows high-reliability and good fit was generated, while construct validity was provided through convergent and discriminant analyses.

The negative consequences of other students' drinking: inventory development and assessment of differences by student characteristics and risk behaviors.

PubMed

Rhodes, Scott D; McCoy, Thomas P; Omli, Morrow R; Cohen, Gail M; Wagoner, Kimberly G; Durant, Robert H; Vissman, Aaron T; Wolfson, Mark

2009-01-01

College students continue to report being disrupted by other students' alcohol use. This study was designed to develop measures to document the consequences resulting from other students' drinking and identify differences in experiencing these consequences by student characteristics and drinking behaviors. A stratified random sample of undergraduate students (N = 3,908) from ten universities in North Carolina, USA, completed a web-based assessment. Exploratory factor analysis (EFA) was performed on the random first split-half sample (n = 1,954) to identify factor structure. Confirmatory factor analysis (CFA) was performed on the remaining half sample (n = 1,954) using structural equation modeling. EFA revealed two inventories: interpersonal and community consequences of others' drinking inventories. CFA on the second split-half sample identified model fits for the two factor structure suggested by EFA. Of 3,908 participants, 78% reported experiencing one or more consequences due to others' drinking during the past 30 days. Multivariable generalized linear mixed modeling further validated the inventories and resulted in several associations. Male students who reported getting drunk experienced significantly more interpersonal consequences from others' drinking (p < .001). Minority students, students who lived on campus and students who reported getting drunk experienced significantly more community consequences from others' drinking (p < .01). These findings demonstrate that 4 out of 5 college students experience consequences from others' drinking, and consequences vary for different subgroups of students. Although these inventories should be tested further, these findings propose standardized measures that may be useful to assess the consequences of others' drinking among college students.

The reliability of information on work-related injuries available from hospitalisation data in Australia.

PubMed

McKenzie, Kirsten; Mitchell, Rebecca; Scott, Deborah Anne; Harrison, James Edward; McClure, Roderick John

2009-08-01

To examine the reliability of work-related activity coding for injury-related hospitalisations in Australia. A random sample of 4,373 injury-related hospital separations from 1 July 2002 to 30 June 2004 were obtained from a stratified random sample of 50 hospitals across four states in Australia. From this sample, cases were identified as work-related if they contained an ICD-10-AM work-related activity code (U73) allocated by either: (i) the original coder; (ii) an independent auditor, blinded to the original code; or (iii) a research assistant, blinded to both the original and auditor codes, who reviewed narrative text extracted from the medical record. The concordance of activity coding and number of cases identified as work-related using each method were compared. Of the 4,373 cases sampled, 318 cases were identified as being work-related using any of the three methods for identification. The original coder identified 217 and the auditor identified 266 work-related cases (68.2% and 83.6% of the total cases identified, respectively). Around 10% of cases were only identified through the text description review. The original coder and auditor agreed on the assignment of work-relatedness for 68.9% of cases. The best estimates of the frequency of hospital admissions for occupational injury underestimate the burden by around 32%. This is a substantial underestimate that has major implications for public policy, and highlights the need for further work on improving the quality and completeness of routine, administrative data sources for a more complete identification of work-related injuries.

Assessing the quality of reproductive health services in Egypt via exit interviews.

PubMed

Zaky, Hassan H M; Khattab, Hind A S; Galal, Dina

2007-05-01

This study assesses the quality of reproductive health services using client satisfaction exit interviews among three groups of primary health care units run by the Ministry of Health and Population of Egypt. Each group applied a different model of intervention. The Ministry will use the results in assessing its reproductive health component in the health sector reform program, and benefits from the strengths of other models of intervention. The sample was selected in two stages. First, a stratified random sampling procedure was used to select the health units. Then the sample of female clients in each health unit was selected using the systematic random approach, whereby one in every two women visiting the unit was approached. All women in the sample coming for reproductive health services were included in the analysis. The results showed that reproductive health beneficiaries at the units implementing the new health sector reform program were more satisfied with the quality of services. Still there were various areas where clients showed significant dissatisfaction, such as waiting time, interior furnishings, cleanliness of the units and consultation time. The study showed that the staff of these units did not provide a conductive social environment as other interventions did. A significant proportion of women expressed their intention to go to private physicians owing to their flexible working hours and variety specializations. Beneficiaries were generally more satisfied with the quality of health services after attending the reformed units than the other types of units, but the generalization did not fully apply. Areas of weakness are identified.

Forest inventory and stratified estimation: a cautionary note

Treesearch

John Coulston

2008-01-01

The Forest Inventory and Analysis (FIA) Program uses stratified estimation techniques to produce estimates of forest attributes. Stratification must be unbiased and stratification procedures should be examined to identify any potential bias. This note explains simple techniques for identifying potential bias, discriminating between sample bias and stratification bias,...

[Motivation to change unhealthy life styles and cardiovascular risk].

PubMed

Pérez-Manchón, David; Alvarez-García, Gema María; González-López, Esteban

2014-01-01

Study the relationship between motivation to change unhealthy life styles and cardiovascular risk. Cross sectional study, random, stratified by age, carried out in the field of primary care with a sample of 369 people. It was felt that with smoking or smoking cessation active consumption less than a year, the physical habit was valued at work and leisure, food habits were assessed in adherence to mediterranean diet and the stages of motivation were categorized precontemplative phase to maintenance phase. The cardiovascular risk was stratified with the SCORE table calibrated in Spain. The 49.6% were men and 50.4% were women, with an average age of 41.2 years. The prevalence of smoking was 31.4% (95% CI 26.56-36,30), 58% in sedentary lifestyle (95% CI 52.27-62,63) and 68% for bad diet (95% CI 63.97-73,69). The 69.8% of smokers, 77.8% of sedentary and 48.4% of people without proper diet was precontemplative to change their lifestyles. Precontemplative stages in unhealthy life styles have association with risk factors and increase the global cardiovascular risk. The transtheoretical model is a useful tool for the assessment of unhealthy behaviors in lifestyles. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

Assessing the sustainable construction of large construction companies in Malaysia

NASA Astrophysics Data System (ADS)

Adewale, Bamgbade Jibril; Mohammed, Kamaruddeen Ahmed; Nasrun, Mohd Nawi Mohd

2016-08-01

Considering the increasing concerns for the consideration of sustainability issues in construction project delivery within the construction industry, this paper assesses the extent of sustainable construction among Malaysian large contractors, in order to ascertain the level of the industry's impacts on both the environment and the society. Sustainable construction explains the construction industry's responsibility to efficiently utilise the finite resources while also reducing construction impacts on both humans and the environment throughout the phases of construction. This study used proportionate stratified random sampling to conduct a field study with a sample of 172 contractors out of the 708 administered questionnaires. Data were collected from large contractors in the eleven states of peninsular Malaysia. Using the five-level rating scale (which include: 1= Very Low; 2= Low; 3= Moderate; 4= High; 5= Very High) to describe the level of sustainable construction of Malaysian contractors based on previous studies, statistical analysis reveals that environmental, social and economic sustainability of Malaysian large contractors are high.

SCIENTIFIC PAPER PRESENTATION DURING CONCURRENT INTEREST SESSION. Community Health Nursing (Speciality). Iron-deficiency anemia.

PubMed

Kala, K

2015-01-01

Iron deficiency anaemia is the most common form of malnutrition in the world. The global prevalence of anaemia mainly in South East Asia is 65.5 percent, in India 56 percent among adolescent girls. A study conducted to assess the effectiveness of structured teaching programme on knowledge and attitude of adolescent girls in prevention of iron and folic acid deficiency anaemia at a selected corporation school. It adopted one group pre-test post-test design with 60 samples selected by employing stratified random sampling technique. The study revealed that during pre-test 90 percent of them had inadequate knowledge and 65 percent of them had unfavourable attitude towards iron and folic acid deficiency anaemia. After the structured teaching programme the knowledge and attitude was improved (73% had adequate knowledge and 79% had most favourable attitude). Overall the structured teaching programme was found effective in improving the knowledge and attitude of adolescent girls in prevention of iron and folic acid deficiency anaemia.

Undergraduate study in psychology: Curriculum and assessment.

PubMed

Norcross, John C; Hailstorks, Robin; Aiken, Leona S; Pfund, Rory A; Stamm, Karen E; Christidis, Peggy

2016-01-01

The undergraduate curriculum in psychology profoundly reflects and shapes the discipline. Yet, reliable information on the undergraduate psychology curriculum has been difficult to acquire due to insufficient research carried out on unrepresentative program samples with disparate methods. In 2014, APA launched the first systematic effort in a decade to gather national data on the psychology major and program outcomes. We surveyed a stratified random sample of department chairs/coordinators of accredited colleges and universities in the United States that offer undergraduate courses and programs in psychology. A total of 439 undergraduate psychology programs (45.2%) completed the survey. This article summarizes, for both associate and baccalaureate programs, the results of the Undergraduate Study in Psychology. Current practices concerning the introductory course, the courses offered, core requirements, the psychology minor, and tracks/concentrations are presented. The frequency of formal program reviews and program-level assessment methods are also addressed. By extending prior research on the undergraduate curriculum, we chronicle longitudinal changes in the psychology major over the past 20 years. (c) 2016 APA, all rights reserved).

Stressors and reactions to stressors among university students.

PubMed

Hamaideh, Shaher H

2011-01-01

University students are prone to stressors due to the transitional nature of university life. High levels of stress are believed to affect students' health as well as their academic performance. The aims of this study were to identify stressors and reactions to stressors among university students, and to examine the correlations between student stressors and study variables. A correlational descriptive design was used. Student-life Stress Inventory (SSI) was used to measure the stressors and reactions to stressors. Stratified random sampling was employed to recruit participants. The final sample consisted of 877 participants (students). s indicated that the highest group of stressors experienced by students were 'self-imposed' stressors followed by 'pressures'. Cognitive responses were found to be the highest responses to stressors experienced by students. Negative correlations were found with student's perception of health, and father's and mother's level of education. This study revealed that stressors among university students come from 'self-imposed' stressors and 'pressures'. Stress management, assertiveness skills, time management and counselling sessions will be effective in reducing stress experienced by students.