Prevalence of Mixed-Methods Sampling Designs in Social Science Research

ERIC Educational Resources Information Center

Collins, Kathleen M. T.

2006-01-01

The purpose of this mixed-methods study was to document the prevalence of sampling designs utilised in mixed-methods research and to examine the interpretive consistency between interpretations made in mixed-methods studies and the sampling design used. Classification of studies was based on a two-dimensional mixed-methods sampling model. This…

Integrating Prospective Longitudinal Data: Modeling Personality and Health in the Terman Life Cycle and Hawaii Longitudinal Studies

PubMed Central

Kern, Margaret L.; Hampson, Sarah E.; Goldberg, Lewis R.; Friedman, Howard S.

2013-01-01

The present study used a collaborative framework to integrate two long-term prospective studies: the Terman Life Cycle Study and the Hawaii Personality and Health Longitudinal Study. Using a five-factor personality-trait framework, teacher assessments of child personality were rationally and empirically aligned to establish similar factor structures across samples. Comparable items related to adult self-rated health, education, and alcohol use were harmonized, and data were pooled on harmonized items. A structural model was estimated, allowing paths to differ by sample. Harmonized child personality factors were then used to examine markers of physiological dysfunction in the Hawaii sample and mortality risk in the Terman sample. Harmonized conscientiousness predicted less physiological dysfunction in the Hawaii sample and lower mortality risk in the Terman sample. These results illustrate how collaborative, integrative work with multiple samples offers the exciting possibility that samples from different cohorts and ages can be linked together to directly test lifespan theories of personality and health. PMID:23231689

CTEPP STANDARD OPERATING PROCEDURE FOR PACKING AND SHIPPING STUDY SAMPLES (SOP-3.11)

EPA Science Inventory

This SOP describes the methods for packing and shipping study samples. These methods are for packing and shipping biological and environmental samples. The methods have been tested and used in the previous pilot studies.

Oppositional Behavior and Anxiety in Boys and Girls: A Cross-Sectional Study in Two Community Samples

ERIC Educational Resources Information Center

Mireault, Gina; Rooney, Siri; Kouwenhoven, Kristen; Hannan, Carolyn

2008-01-01

Studies have repeatedly shown that oppositional behavior is linked to anxiety in clinical samples of children. This study explored whether these variables were similarly related in nonclinical samples of elementary and middle school students (N = 302). Despite greater self-reported oppositional behavior among boys in these samples, anxiety…

A Mixed Methods Investigation of Mixed Methods Sampling Designs in Social and Health Science Research

ERIC Educational Resources Information Center

Collins, Kathleen M. T.; Onwuegbuzie, Anthony J.; Jiao, Qun G.

2007-01-01

A sequential design utilizing identical samples was used to classify mixed methods studies via a two-dimensional model, wherein sampling designs were grouped according to the time orientation of each study's components and the relationship of the qualitative and quantitative samples. A quantitative analysis of 121 studies representing nine fields…

Capturing heterogeneity: The role of a study area's extent for estimating mean throughfall

NASA Astrophysics Data System (ADS)

Zimmermann, Alexander; Voss, Sebastian; Metzger, Johanna Clara; Hildebrandt, Anke; Zimmermann, Beate

2016-11-01

The selection of an appropriate spatial extent of a sampling plot is one among several important decisions involved in planning a throughfall sampling scheme. In fact, the choice of the extent may determine whether or not a study can adequately characterize the hydrological fluxes of the studied ecosystem. Previous attempts to optimize throughfall sampling schemes focused on the selection of an appropriate sample size, support, and sampling design, while comparatively little attention has been given to the role of the extent. In this contribution, we investigated the influence of the extent on the representativeness of mean throughfall estimates for three forest ecosystems of varying stand structure. Our study is based on virtual sampling of simulated throughfall fields. We derived these fields from throughfall data sampled in a simply structured forest (young tropical forest) and two heterogeneous forests (old tropical forest, unmanaged mixed European beech forest). We then sampled the simulated throughfall fields with three common extents and various sample sizes for a range of events and for accumulated data. Our findings suggest that the size of the study area should be carefully adapted to the complexity of the system under study and to the required temporal resolution of the throughfall data (i.e. event-based versus accumulated). Generally, event-based sampling in complex structured forests (conditions that favor comparatively long autocorrelations in throughfall) requires the largest extents. For event-based sampling, the choice of an appropriate extent can be as important as using an adequate sample size.

An internal pilot design for prospective cancer screening trials with unknown disease prevalence.

PubMed

Brinton, John T; Ringham, Brandy M; Glueck, Deborah H

2015-10-13

For studies that compare the diagnostic accuracy of two screening tests, the sample size depends on the prevalence of disease in the study population, and on the variance of the outcome. Both parameters may be unknown during the design stage, which makes finding an accurate sample size difficult. To solve this problem, we propose adapting an internal pilot design. In this adapted design, researchers will accrue some percentage of the planned sample size, then estimate both the disease prevalence and the variances of the screening tests. The updated estimates of the disease prevalence and variance are used to conduct a more accurate power and sample size calculation. We demonstrate that in large samples, the adapted internal pilot design produces no Type I inflation. For small samples (N less than 50), we introduce a novel adjustment of the critical value to control the Type I error rate. We apply the method to two proposed prospective cancer screening studies: 1) a small oral cancer screening study in individuals with Fanconi anemia and 2) a large oral cancer screening trial. Conducting an internal pilot study without adjusting the critical value can cause Type I error rate inflation in small samples, but not in large samples. An internal pilot approach usually achieves goal power and, for most studies with sample size greater than 50, requires no Type I error correction. Further, we have provided a flexible and accurate approach to bound Type I error below a goal level for studies with small sample size.

Research and development of a field-ready protocol for sampling of phosgene from stationary source emissions: Diethylamine reagent studies. Research report, 11 July 1995--30 September 1996

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

Steger, J.L.; Bursey, J.T.; Merrill, R.G.

1999-03-01

This report presents the results of laboratory studies to develop and evaluate a method for the sampling and analysis of phosgene from stationary sources of air emissions using diethylamine (DEA) in toluene as the collection media. The method extracts stack gas from emission sources and stabilizes the reactive gas for subsequent analysis. DEA was evaluated both in a benchtop study and in a laboratory train spiking study. This report includes results for both the benchtop study and the train spiking study. Benchtop studies to evaluate the suitability of DEA for collecting and analyzing phosgene investigated five variables: storage time, DEAmore » concentration, moisture/pH, phosgene concentration, and sample storage temperature. Prototype sampling train studies were performed to determine if the benchtop chemical studies were transferable to a Modified Method 5 sampling train collecting phosgene in the presence of clean air mixed with typical stack gas components. Four conditions, which varied the moisture and phosgene spike were evaluated in triplicate. In addition to research results, the report includes a detailed draft method for sampling and analysis of phosgene from stationary source emissions.« less

The accuracy of endometrial sampling in women with postmenopausal bleeding: a systematic review and meta-analysis.

PubMed

van Hanegem, Nehalennia; Prins, Marileen M C; Bongers, Marlies Y; Opmeer, Brent C; Sahota, Daljit Singh; Mol, Ben Willem J; Timmermans, Anne

2016-02-01

Postmenopausal bleeding (PMB) can be the first sign of endometrial cancer. In case of thickened endometrium, endometrial sampling is often used in these women. In this systematic review, we studied the accuracy of endometrial sampling for the diagnoses of endometrial cancer, atypical hyperplasia and endometrial disease (endometrial pathology, including benign polyps). We systematically searched the literature for studies comparing the results of endometrial sampling in women with postmenopausal bleeding with two different reference standards: blind dilatation and curettage (D&C) and hysteroscopy with histology. We assessed the quality of the detected studies by the QUADAS-2 tool. For each included study, we calculated the fraction of women in whom endometrial sampling failed. Furthermore, we extracted numbers of cases of endometrial cancer, atypical hyperplasia and endometrial disease that were identified or missed by endometrial sampling. We detected 12 studies reporting on 1029 women with postmenopausal bleeding: five studies with dilatation and curettage (D&C) and seven studies with hysteroscopy as a reference test. The weighted sensitivity of endometrial sampling with D&C as a reference for the diagnosis of endometrial cancer was 100% (range 100-100%) and 92% (71-100) for the diagnosis of atypical hyperplasia. Only one study reported sensitivity for endometrial disease, which was 76%. When hysteroscopy was used as a reference, weighted sensitivities of endometrial sampling were 90% (range 50-100), 82% (range 56-94) and 39% (21-69) for the diagnosis of endometrial cancer, atypical hyperplasia and endometrial disease, respectively. For all diagnosis studied and the reference test used, specificity was 98-100%. The weighted failure rate of endometrial sampling was 11% (range 1-53%), while insufficient samples were found in 31% (range 7-76%). In these women with insufficient or failed samples, an endometrial (pre) cancer was found in 7% (range 0-18%). In women with postmenopausal bleeding, the sensitivity of endometrial sampling to detect endometrial cancer and especially atypical hyperplasia and endometrial disease, including endometrial polyps, is lower than previously thought. Therefore, further diagnostic work-up for focal pathology is warranted, after a benign result of endometrial sampling. Copyright © 2015. Published by Elsevier Ireland Ltd.

The generalization ability of SVM classification based on Markov sampling.

PubMed

Xu, Jie; Tang, Yuan Yan; Zou, Bin; Xu, Zongben; Li, Luoqing; Lu, Yang; Zhang, Baochang

2015-06-01

The previously known works studying the generalization ability of support vector machine classification (SVMC) algorithm are usually based on the assumption of independent and identically distributed samples. In this paper, we go far beyond this classical framework by studying the generalization ability of SVMC based on uniformly ergodic Markov chain (u.e.M.c.) samples. We analyze the excess misclassification error of SVMC based on u.e.M.c. samples, and obtain the optimal learning rate of SVMC for u.e.M.c. We also introduce a new Markov sampling algorithm for SVMC to generate u.e.M.c. samples from given dataset, and present the numerical studies on the learning performance of SVMC based on Markov sampling for benchmark datasets. The numerical studies show that the SVMC based on Markov sampling not only has better generalization ability as the number of training samples are bigger, but also the classifiers based on Markov sampling are sparsity when the size of dataset is bigger with regard to the input dimension.

Limited-sampling strategies for anti-infective agents: systematic review.

PubMed

Sprague, Denise A; Ensom, Mary H H

2009-09-01

Area under the concentration-time curve (AUC) is a pharmacokinetic parameter that represents overall exposure to a drug. For selected anti-infective agents, pharmacokinetic-pharmacodynamic parameters, such as AUC/MIC (where MIC is the minimal inhibitory concentration), have been correlated with outcome in a few studies. A limited-sampling strategy may be used to estimate pharmacokinetic parameters such as AUC, without the frequent, costly, and inconvenient blood sampling that would be required to directly calculate the AUC. To discuss, by means of a systematic review, the strengths, limitations, and clinical implications of published studies involving a limited-sampling strategy for anti-infective agents and to propose improvements in methodology for future studies. The PubMed and EMBASE databases were searched using the terms "anti-infective agents", "limited sampling", "optimal sampling", "sparse sampling", "AUC monitoring", "abbreviated AUC", "abbreviated sampling", and "Bayesian". The reference lists of retrieved articles were searched manually. Included studies were classified according to modified criteria from the US Preventive Services Task Force. Twenty studies met the inclusion criteria. Six of the studies (involving didanosine, zidovudine, nevirapine, ciprofloxacin, efavirenz, and nelfinavir) were classified as providing level I evidence, 4 studies (involving vancomycin, didanosine, lamivudine, and lopinavir-ritonavir) provided level II-1 evidence, 2 studies (involving saquinavir and ceftazidime) provided level II-2 evidence, and 8 studies (involving ciprofloxacin, nelfinavir, vancomycin, ceftazidime, ganciclovir, pyrazinamide, meropenem, and alpha interferon) provided level III evidence. All of the studies providing level I evidence used prospectively collected data and proper validation procedures with separate, randomly selected index and validation groups. However, most of the included studies did not provide an adequate description of the methods or the characteristics of included patients, which limited their generalizability. Many limited-sampling strategies have been developed for anti-infective agents that do not have a clearly established link between AUC and clinical outcomes in humans. Future studies should first determine if there is an association between AUC monitoring and clinical outcomes. Thereafter, it may be worthwhile to prospectively develop and validate a limited-sampling strategy for the particular anti-infective agent in a similar population.

A measure of the signal-to-noise ratio of microarray samples and studies using gene correlations.

PubMed

Venet, David; Detours, Vincent; Bersini, Hugues

2012-01-01

The quality of gene expression data can vary dramatically from platform to platform, study to study, and sample to sample. As reliable statistical analysis rests on reliable data, determining such quality is of the utmost importance. Quality measures to spot problematic samples exist, but they are platform-specific, and cannot be used to compare studies. As a proxy for quality, we propose a signal-to-noise ratio for microarray data, the "Signal-to-Noise Applied to Gene Expression Experiments", or SNAGEE. SNAGEE is based on the consistency of gene-gene correlations. We applied SNAGEE to a compendium of 80 large datasets on 37 platforms, for a total of 24,380 samples, and assessed the signal-to-noise ratio of studies and samples. This allowed us to discover serious issues with three studies. We show that signal-to-noise ratios of both studies and samples are linked to the statistical significance of the biological results. We showed that SNAGEE is an effective way to measure data quality for most types of gene expression studies, and that it often outperforms existing techniques. Furthermore, SNAGEE is platform-independent and does not require raw data files. The SNAGEE R package is available in BioConductor.

Work Sampling Study of an Engineering Professor during a Regular Contract Period

ERIC Educational Resources Information Center

Brink, Jan; McDonald, Dale B.

2015-01-01

Work sampling is a technique that has been employed in industry and fields such as healthcare for some time. It is a powerful technique, and an alternative to conventional stop watch time studies, used by industrial engineers to focus upon random work sampling observations. This study applies work sampling to the duties performed by an individual…

Optical Methods for Identifying Hard Clay Core Samples During Petrophysical Studies

NASA Astrophysics Data System (ADS)

Morev, A. V.; Solovyeva, A. V.; Morev, V. A.

2018-01-01

X-ray phase analysis of the general mineralogical composition of core samples from one of the West Siberian fields was performed. Electronic absorption spectra of the clay core samples with an added indicator were studied. The speed and availability of applying the two methods in petrophysical laboratories during sample preparation for standard and special studies were estimated.

Validation sampling can reduce bias in healthcare database studies: an illustration using influenza vaccination effectiveness

PubMed Central

Nelson, Jennifer C.; Marsh, Tracey; Lumley, Thomas; Larson, Eric B.; Jackson, Lisa A.; Jackson, Michael

2014-01-01

Objective Estimates of treatment effectiveness in epidemiologic studies using large observational health care databases may be biased due to inaccurate or incomplete information on important confounders. Study methods that collect and incorporate more comprehensive confounder data on a validation cohort may reduce confounding bias. Study Design and Setting We applied two such methods, imputation and reweighting, to Group Health administrative data (full sample) supplemented by more detailed confounder data from the Adult Changes in Thought study (validation sample). We used influenza vaccination effectiveness (with an unexposed comparator group) as an example and evaluated each method’s ability to reduce bias using the control time period prior to influenza circulation. Results Both methods reduced, but did not completely eliminate, the bias compared with traditional effectiveness estimates that do not utilize the validation sample confounders. Conclusion Although these results support the use of validation sampling methods to improve the accuracy of comparative effectiveness findings from healthcare database studies, they also illustrate that the success of such methods depends on many factors, including the ability to measure important confounders in a representative and large enough validation sample, the comparability of the full sample and validation sample, and the accuracy with which data can be imputed or reweighted using the additional validation sample information. PMID:23849144

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

PubMed

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

2014-01-01

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

Urban Land Cover Mapping Accuracy Assessment - A Cost-benefit Analysis Approach

NASA Astrophysics Data System (ADS)

Xiao, T.

2012-12-01

One of the most important components in urban land cover mapping is mapping accuracy assessment. Many statistical models have been developed to help design simple schemes based on both accuracy and confidence levels. It is intuitive that an increased number of samples increases the accuracy as well as the cost of an assessment. Understanding cost and sampling size is crucial in implementing efficient and effective of field data collection. Few studies have included a cost calculation component as part of the assessment. In this study, a cost-benefit sampling analysis model was created by combining sample size design and sampling cost calculation. The sampling cost included transportation cost, field data collection cost, and laboratory data analysis cost. Simple Random Sampling (SRS) and Modified Systematic Sampling (MSS) methods were used to design sample locations and to extract land cover data in ArcGIS. High resolution land cover data layers of Denver, CO and Sacramento, CA, street networks, and parcel GIS data layers were used in this study to test and verify the model. The relationship between the cost and accuracy was used to determine the effectiveness of each sample method. The results of this study can be applied to other environmental studies that require spatial sampling.

Preserving, Enhancing, and Continuing the Scientific Legacy of the Apollo Sample Suite

NASA Astrophysics Data System (ADS)

Zeigler, R. A.; Evans, C. A.; Lehnert, K.; Cai, Y.; Todd, N. S.

2016-12-01

From 1969 to 1972, Apollo astronauts collected 382 kg of rocks, soils, and core samples from six geologically diverse locations on the Moon. In the nearly 50 years since the samples were collected, over 3000 different studies have been conducted using the nearly 2200 different Apollo samples. Despite the maturity of the sample collection, many new studies of lunar samples are undertaken each year, with an average of >55 requests and >600 distinct subsamples allocated annually over the past five years. The Apollo samples are a finite resource, however. Although new studies are encouraged, it is important that new studies do not duplicate previous studies, and where possible, leverage previous results to inform and enhance the current studies. This helps to preserve the samples and scientific funding, both of which are precious resources. We have initiated several new efforts to rescue some of the early analyses from these samples, including unpublished analytical data. We are actively scanning NASA documentation in paper form that is related to the Apollo missions and sample processing, and we are collaborating with IEDA to establish a geochemical data base called MoonDB. To populate this database, we are actively working with about a dozen prominent lunar PIs to organize and transcribe years of both published and unpublished data, making it available to all researchers. This effort will also take advantage of new online analytical tools like PetDB. There have already been tangible results from the MoonDB data rescue effort. A pilot project involving the rescue of geochemical data of John Delano on Apollo pyroclastic glasses has already been referenced in multiple Apollo sample requests, and in fact, the compiled data was used as part of one of the new studies. Similarly, scanned sample handling reports have been utilized to find previously analyzed samples that were appropriate to fulfill new sample requests. We have also begun to image the Apollo samples using (1) micro-CT scanning to document the interior structure of samples, and (2) comprehensive high resolution photography of samples, enabling high resolution 3D reconstructions of the samples. Both efforts will provide comprehensive access to these samples and allow for more targeted requests, and thus better curation of the samples for decades to come.

Preserving, Enhancing, and Continuing the Scientific Legacy of the Apollo Sample Suite

NASA Technical Reports Server (NTRS)

Zeigler, Ryan; Evans, Cindy; Cai, Yue; Lehnert, Kerstin; Todd, Nancy; Blumenfeld, Erika

2016-01-01

From 1969 to 1972, Apollo astronauts collected 382 kg of rocks, soils, and core samples from six geologically diverse locations on the Moon. In the nearly 50 years since the samples were collected, over 3000 different studies have been conducted using the nearly 2200 different Apollo samples. Despite the maturity of the sample collection, many new studies of lunar samples are undertaken each year, with an average of more than 55 requests and more than 600 distinct subsamples allocated annually over the past five years. The Apollo samples are a finite resource, however. Although new studies are encouraged, it is important that new studies do not duplicate previous studies, and where possible, leverage previous results to inform and enhance the current studies. This helps to preserve the samples and scientific funding, both of which are precious resources. We have initiated several new efforts to rescue some of the early analyses from these samples, including unpublished analytical data. We are actively scanning NASA documentation in paper form that is related to the Apollo missions and sample processing, and we are collaborating with IEDA to establish a geochemical data base called MoonDB. To populate this database, we are actively working with about a dozen prominent lunar PIs to organize and transcribe years of both published and unpublished data, making it available to all researchers. This effort will also take advantage of new online analytical tools like PetDB. There have already been tangible results from the MoonDB data rescue effort. A pilot project involving the rescue of geochemical data of John Delano on Apollo pyroclastic glasses has already been referenced in multiple Apollo sample requests, and in fact, the compiled data was used as part of one of the new studies. Similarly, scanned sample handling reports have been utilized to find previously analyzed samples that were appropriate to fulfill new sample requests. We have also begun to image the Apollo samples using (1) micro-CT scanning to document the interior structure of samples, and (2) comprehensive high resolution photography of samples, enabling high resolution 3D reconstructions of the samples. Both efforts will provide comprehensive access to these samples and allow for more targeted requests, and thus better curation of the samples for decades to come.

Evaluation of Primary Immunization Coverage of Infants Under Universal Immunization Programme in an Urban Area of Bangalore City Using Cluster Sampling and Lot Quality Assurance Sampling Techniques

PubMed Central

K, Punith; K, Lalitha; G, Suman; BS, Pradeep; Kumar K, Jayanth

2008-01-01

Research Question: Is LQAS technique better than cluster sampling technique in terms of resources to evaluate the immunization coverage in an urban area? Objective: To assess and compare the lot quality assurance sampling against cluster sampling in the evaluation of primary immunization coverage. Study Design: Population-based cross-sectional study. Study Setting: Areas under Mathikere Urban Health Center. Study Subjects: Children aged 12 months to 23 months. Sample Size: 220 in cluster sampling, 76 in lot quality assurance sampling. Statistical Analysis: Percentages and Proportions, Chi square Test. Results: (1) Using cluster sampling, the percentage of completely immunized, partially immunized and unimmunized children were 84.09%, 14.09% and 1.82%, respectively. With lot quality assurance sampling, it was 92.11%, 6.58% and 1.31%, respectively. (2) Immunization coverage levels as evaluated by cluster sampling technique were not statistically different from the coverage value as obtained by lot quality assurance sampling techniques. Considering the time and resources required, it was found that lot quality assurance sampling is a better technique in evaluating the primary immunization coverage in urban area. PMID:19876474

42 CFR 402.109 - Statistical sampling.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 2 2011-10-01 2011-10-01 false Statistical sampling. 402.109 Section 402.109... Statistical sampling. (a) Purpose. CMS or OIG may introduce the results of a statistical sampling study to... or caused to be presented. (b) Prima facie evidence. The results of the statistical sampling study...

42 CFR 402.109 - Statistical sampling.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 2 2010-10-01 2010-10-01 false Statistical sampling. 402.109 Section 402.109... Statistical sampling. (a) Purpose. CMS or OIG may introduce the results of a statistical sampling study to... or caused to be presented. (b) Prima facie evidence. The results of the statistical sampling study...

Investigating the Relationship between Self-Handicapping Tendencies, Self-Esteem and Cognitive Distortions

ERIC Educational Resources Information Center

Yavuzer, Yasemin

2015-01-01

The purpose of this study is to examine the relationship between cognitive distortions, self-handicapping tendencies, and self-esteem in a sample of students studying in a school of education. The sample of the study was comprised of 507 volunteer students chosen through random sampling from a total of 4,720 students who were studying teaching at…

General statistical considerations

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

Eberhardt, L L; Gilbert, R O

From NAEG plutonium environmental studies program meeting; Las Vegas, Nevada, USA (2 Oct 1973). The high sampling variability encountered in environmental plutonium studies along with high analytical costs makes it very important that efficient soil sampling plans be used. However, efficient sampling depends on explicit and simple statements of the objectives of the study. When there are multiple objectives it may be difficult to devise a wholly suitable sampling scheme. Sampling for long-term changes in plutonium concentration in soils may also be complex and expensive. Further attention to problems associated with compositing samples is recommended, as is the consistent usemore » of random sampling as a basic technique. (auth)« less

A standardized method for sampling and extraction methods for quantifying microplastics in beach sand.

PubMed

Besley, Aiken; Vijver, Martina G; Behrens, Paul; Bosker, Thijs

2017-01-15

Microplastics are ubiquitous in the environment, are frequently ingested by organisms, and may potentially cause harm. A range of studies have found significant levels of microplastics in beach sand. However, there is a considerable amount of methodological variability among these studies. Methodological variation currently limits comparisons as there is no standard procedure for sampling or extraction of microplastics. We identify key sampling and extraction procedures across the literature through a detailed review. We find that sampling depth, sampling location, number of repeat extractions, and settling times are the critical parameters of variation. Next, using a case-study we determine whether and to what extent these differences impact study outcomes. By investigating the common practices identified in the literature with the case-study, we provide a standard operating procedure for sampling and extracting microplastics from beach sand. Copyright © 2016 Elsevier Ltd. All rights reserved.

Formaldehyde Exposures in a University Anatomy Laboratory

NASA Astrophysics Data System (ADS)

Winkler, Kyle William

Air sampling studies were conducted within a university anatomical laboratory during the embalmment of a cadaver in order to determine if dangerous concentrations of formaldehyde existed. Three air sampling studies were conducted in the anatomical laboratory on three separate days that a cadaver was being embalmed. Samples were collected and analyzed using the Occupational Safety and Health Administration (OSHA) Sampling and Analytical Methods: Method 52. Each air sampling study sampled for short term exposure limit (STEL) and time weighted mean (TWA) breathing zone formaldehyde concentrations as well as area TWA formaldehyde concentrations. A personal aldehyde monitor was also used in each air sampling study to sample for breathing zone formaldehyde concentrations. Measured TWA mean exposures to formaldehyde ranged from 0.15--1.3 parts per million (ppm), STEL formaldehyde exposures ranged from 0.019--0.64 ppm, and eight-hour TWAs ranged from 0.03 to 3.6 ppm. All 8-hour TWA formaldehyde concentrations sampled in the anatomy laboratory during an embalmment were less than the permissible exposure limit (PEL) required by OSHA.

Towards robust and repeatable sampling methods in eDNA based studies.

PubMed

Dickie, Ian A; Boyer, Stephane; Buckley, Hannah; Duncan, Richard P; Gardner, Paul; Hogg, Ian D; Holdaway, Robert J; Lear, Gavin; Makiola, Andreas; Morales, Sergio E; Powell, Jeff R; Weaver, Louise

2018-05-26

DNA based techniques are increasingly used for measuring the biodiversity (species presence, identity, abundance and community composition) of terrestrial and aquatic ecosystems. While there are numerous reviews of molecular methods and bioinformatic steps, there has been little consideration of the methods used to collect samples upon which these later steps are based. This represents a critical knowledge gap, as methodologically sound field sampling is the foundation for subsequent analyses. We reviewed field sampling methods used for metabarcoding studies of both terrestrial and freshwater ecosystem biodiversity over a nearly three-year period (n = 75). We found that 95% (n = 71) of these studies used subjective sampling methods, inappropriate field methods, and/or failed to provide critical methodological information. It would be possible for researchers to replicate only 5% of the metabarcoding studies in our sample, a poorer level of reproducibility than for ecological studies in general. Our findings suggest greater attention to field sampling methods and reporting is necessary in eDNA-based studies of biodiversity to ensure robust outcomes and future reproducibility. Methods must be fully and accurately reported, and protocols developed that minimise subjectivity. Standardisation of sampling protocols would be one way to help to improve reproducibility, and have additional benefits in allowing compilation and comparison of data from across studies. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Testing how voluntary participation requirements in an environmental study affect the planned random sample design outcomes: implications for the predictions of values and their uncertainty.

NASA Astrophysics Data System (ADS)

Ander, Louise; Lark, Murray; Smedley, Pauline; Watts, Michael; Hamilton, Elliott; Fletcher, Tony; Crabbe, Helen; Close, Rebecca; Studden, Mike; Leonardi, Giovanni

2015-04-01

Random sampling design is optimal in order to be able to assess outcomes, such as the mean of a given variable across an area. However, this optimal sampling design may be compromised to an unknown extent by unavoidable real-world factors: the extent to which the study design can still be considered random, and the influence this may have on the choice of appropriate statistical data analysis is examined in this work. We take a study which relied on voluntary participation for the sampling of private water tap chemical composition in England, UK. This study was designed and implemented as a categorical, randomised study. The local geological classes were grouped into 10 types, which were considered to be most important in likely effects on groundwater chemistry (the source of all the tap waters sampled). Locations of the users of private water supplies were made available to the study group from the Local Authority in the area. These were then assigned, based on location, to geological groups 1 to 10 and randomised within each group. However, the permission to collect samples then required active, voluntary participation by householders and thus, unlike many environmental studies, could not always follow the initial sample design. Impediments to participation ranged from 'willing but not available' during the designated sampling period, to a lack of response to requests to sample (assumed to be wholly unwilling or unable to participate). Additionally, a small number of unplanned samples were collected via new participants making themselves known to the sampling teams, during the sampling period. Here we examine the impact this has on the 'random' nature of the resulting data distribution, by comparison with the non-participating known supplies. We consider the implications this has on choice of statistical analysis methods to predict values and uncertainty at un-sampled locations.

Study design and percent recoveries of anthropogenic organic compounds with and without the addition of ascorbic acid to preserve water samples containing free chlorine, 2004-06

USGS Publications Warehouse

Valder, Joshua F.; Delzer, Gregory C.; Price, Curtis V.; Sandstrom, Mark W.

2008-01-01

The National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS) began implementing Source Water-Quality Assessments (SWQAs) in 2002 that focus on characterizing the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems in the United States. As used for SWQA studies, source water is the raw (ambient) water collected at the supply well prior to water treatment (for ground water) or the raw (ambient) water collected from the river near the intake (for surface water). Finished water is the water that is treated, which typically involves, in part, the addition of chlorine or other disinfection chemicals to remove pathogens, and is ready to be delivered to consumers. Finished water is collected before the water enters the distribution system. This report describes the study design and percent recoveries of anthropogenic organic compounds (AOCs) with and without the addition of ascorbic acid to preserve water samples containing free chlorine. The percent recoveries were determined by using analytical results from a laboratory study conducted in 2004 by the USGS's National Water Quality Laboratory (NWQL) and from data collected during 2004-06 for a field study currently (2008) being conducted by the USGS's NAWQA Program. The laboratory study was designed to determine if preserving samples with ascorbic acid (quenching samples) adversely affects analytical performance under controlled conditions. During the laboratory study, eight samples of reagent water were spiked for each of five analytical schedules evaluated. Percent recoveries from these samples were then compared in two ways: (1) four quenched reagent spiked samples analyzed on day 0 were compared with four quenched reagent spiked samples analyzed on day 7 or 14, and (2) the combined eight quenched reagent spiked samples analyzed on day 0, 7, or 14 were compared with eight laboratory reagent spikes (LRSs). Percent recoveries from the quenched reagent spiked samples that were analyzed at two different times (day 0 and day 7 or 14) can be used to determine the stability of the quenched samples held for an amount of time representative of the normal amount of time between sample collection and analysis. The comparison between the quenched reagent spiked samples and the LRSs can be used to determine if quenching samples adversely affects the analytical performance under controlled conditions. The field study began in 2004 and is continuing today (February 2008) to characterize the effect of quenching on field-matrix spike recoveries and to better understand the potential oxidation and transformation of 277 AOCs. Three types of samples were collected from 11 NAWQA Study Units across the Nation: (1) quenched finished-water samples (not spiked), (2) quenched finished-water spiked samples, and (3) nonquenched finished-water spiked samples. Percent recoveries of AOCs in quenched and nonquenched finished-water spiked samples collected during 2004-06 are presented. Comparisons of percent recoveries between quenched and nonquenched spiked samples can be used to show how quenching affects finished-water samples. A maximum of 6 surface-water and 7 ground-water quenched finished-water spiked samples paired with nonquenched finished-water spiked samples were analyzed. Analytical results for the field study are presented in two ways: (1) by surface-water supplies or ground-water supplies, and (2) by use (or source) group category for surface-water and ground-water supplies. Graphical representations of percent recoveries for the quenched and nonquenched finished-water spiked samples also are presented.

Effect of a traditional processing method on the chemical composition of local white lupin (Lupinus albus L.) seed in North-Western Ethiopia.

PubMed

Yeheyis, Likawent; Kijora, Claudia; Wink, Michael; Peters, Kurt J

2011-01-01

The effect of a traditional Ethiopian lupin processing method on the chemical composition of lupin seed samples was studied. Two sampling districts, namely Mecha and Sekela, representing the mid- and high-altitude areas of north-western Ethiopia, respectively, were randomly selected. Different types of traditionally processed and marketed lupin seed samples (raw, roasted, and finished) were collected in six replications from each district. Raw samples are unprocessed, and roasted samples are roasted using firewood. Finished samples are those ready for human consumption as snack. Thousand seed weight for raw and roasted samples within a study district was similar (P > 0.05), but it was lower (P < 0.01) for finished samples compared to raw and roasted samples. The crude fibre content of finished lupin seed sample from Mecha was lower (P < 0.01) than that of raw and roasted samples. However, the different lupin samples from Sekela had similar crude fibre content (P > 0.05). The crude protein and crude fat contents of finished samples within a study district were higher (P < 0.01) than those of raw and roasted samples, respectively. Roasting had no effect on the crude protein content of lupin seed samples. The crude ash content of raw and roasted lupin samples within a study district was higher (P < 0.01) than that of finished lupin samples of the respective study districts. The content of quinolizidine alkaloids of finished lupin samples was lower than that of raw and roasted samples. There was also an interaction effect between location and lupin sample type. The traditional processing method of lupin seeds in Ethiopia has a positive contribution improving the crude protein and crude fat content, and lowering the alkaloid content of the finished product. The study showed the possibility of adopting the traditional processing method to process bitter white lupin for the use as protein supplement in livestock feed in Ethiopia, but further work has to be done on the processing method and animal evaluation.

Guidelines and sample protocol for sampling forest gaps.

Treesearch

J.R. Runkle

1992-01-01

A protocol for sampling forest canopy gaps is presented. Methods used in published gap studies are reviewed. The sample protocol will be useful in developing a broader understanding of forest structure and dynamics through comparative studies across different forest ecosystems.

Water- and air-quality monitoring of the Sweetwater Reservoir Watershed, San Diego County, California - Phase One results, continued, 2001-2003

USGS Publications Warehouse

Mendez, Gregory O.; Foreman, William T.; Morita, Andrew; Majewski, Michael S.

2008-01-01

In 1998, the U.S. Geological Survey, in cooperation with the Sweetwater Authority, began a study to monitor water, air, and sediment at the Sweetwater and Loveland Reservoirs in San Diego County, California. The study includes regular sampling of water and air at Sweetwater Reservoir for chemical constituents, including volatile organic compounds (VOC), polynuclear aromatic hydrocarbons (PAH), pesticides, and major and trace elements. The purpose of this study is to monitor changes in contaminant composition and concentration during the construction and operation of State Route 125. To accomplish this, the study was divided into two phases. Phase One sampling (water years 1998–2004) determined baseline conditions for the detection frequency and the concentrations of target compounds in air and water. Phase Two sampling (starting water year 2005) continues at selected monitoring sites during and after construction of State Route 125 to assess the chemical impact this roadway alignment may have on water quality in the reservoir. Water samples were collected for VOCs and pesticides at Loveland Reservoir during Phase One and will be collected during Phase Two for comparison purposes. Air samples collected to monitor changes in VOCs, PAHs, and pesticides were analyzed by adapting methods used to analyze water samples. Bed-sediment samples have been and will be collected three times during the study; at the beginning of Phase One, at the start of Phase Two, and near the end of the study. In addition to the ongoing data collection, several special studies were initiated to assess the occurrence of specific chemicals of concern, such as trace metals, anthropogenic indicator compounds, and pharmaceuticals. This report describes the study design, and the sampling and analytical methods, and presents data from water and air samples collected during the fourth and fifth years of Phase One of the study (October 2001 to September 2003). Data collected during the first three years has been previously published. Three types of quality-control samples were used in this study: blanks, spikes, and replicates. Blanks and spikes are used to estimate result bias, and replicates are used to estimate result variability. Additionally, surrogate compounds were added at the laboratory to samples of VOCs, PAHs, pesticides, anthropogenic indicator compounds, and pharmaceuticals to monitor sample-specific performance of the analytical method.

(PRESENTED NAQC SAN FRANCISCO, CA) COARSE PM METHODS STUDY: STUDY DESIGN AND RESULTS

EPA Science Inventory

Comprehensive field studies were conducted to evaluate the performance of sampling methods for measuring the coarse fraction of PM10 in ambient air. Five separate sampling approaches were evaluated at each of three sampling sites. As the primary basis of comparison, a discrete ...

Integration of DNA sample collection into a multi-site birth defects case-control study.

PubMed

Rasmussen, Sonja A; Lammer, Edward J; Shaw, Gary M; Finnell, Richard H; McGehee, Robert E; Gallagher, Margaret; Romitti, Paul A; Murray, Jeffrey C

2002-10-01

Advances in quantitative analysis and molecular genotyping have provided unprecedented opportunities to add biological sampling and genetic information to epidemiologic studies. The purpose of this article is to describe the incorporation of DNA sample collection into the National Birth Defects Prevention Study (NBDPS), an ongoing case-control study in an eight-state consortium with a primary goal to identify risk factors for birth defects. Babies with birth defects are identified through birth defects surveillance systems in the eight participating centers. Cases are infants with one or more of over 30 major birth defects. Controls are infants without defects from the same geographic area. Epidemiologic information is collected through an hour-long interview with mothers of both cases and controls. We added the collection of buccal cytobrush DNA samples for case-infants, control-infants, and their parents to this study. We describe here the methods by which the samples have been collected and processed, establishment of a centralized resource for DNA banking, and quality control, database management, access, informed consent, and confidentiality issues. Biological sampling and genetic analyses are important components to epidemiologic studies of birth defects aimed at identifying risk factors. The DNA specimens collected in this study can be used for detection of mutations, study of polymorphic variants that confer differential susceptibility to teratogens, and examination of interactions among genetic risk factors. Information on the methods used and issues faced by the NBDPS may be of value to others considering the addition of DNA sampling to epidemiologic studies.

Why sampling scheme matters: the effect of sampling scheme on landscape genetic results

Treesearch

Michael K. Schwartz; Kevin S. McKelvey

2008-01-01

There has been a recent trend in genetic studies of wild populations where researchers have changed their sampling schemes from sampling pre-defined populations to sampling individuals uniformly across landscapes. This reflects the fact that many species under study are continuously distributed rather than clumped into obvious "populations". Once individual...

Sampling in Developmental Science: Situations, Shortcomings, Solutions, and Standards.

PubMed

Bornstein, Marc H; Jager, Justin; Putnick, Diane L

2013-12-01

Sampling is a key feature of every study in developmental science. Although sampling has far-reaching implications, too little attention is paid to sampling. Here, we describe, discuss, and evaluate four prominent sampling strategies in developmental science: population-based probability sampling, convenience sampling, quota sampling, and homogeneous sampling. We then judge these sampling strategies by five criteria: whether they yield representative and generalizable estimates of a study's target population, whether they yield representative and generalizable estimates of subsamples within a study's target population, the recruitment efforts and costs they entail, whether they yield sufficient power to detect subsample differences, and whether they introduce "noise" related to variation in subsamples and whether that "noise" can be accounted for statistically. We use sample composition of gender, ethnicity, and socioeconomic status to illustrate and assess the four sampling strategies. Finally, we tally the use of the four sampling strategies in five prominent developmental science journals and make recommendations about best practices for sample selection and reporting.

[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.

Optimized probability sampling of study sites to improve generalizability in a multisite intervention trial.

PubMed

Kraschnewski, Jennifer L; Keyserling, Thomas C; Bangdiwala, Shrikant I; Gizlice, Ziya; Garcia, Beverly A; Johnston, Larry F; Gustafson, Alison; Petrovic, Lindsay; Glasgow, Russell E; Samuel-Hodge, Carmen D

2010-01-01

Studies of type 2 translation, the adaption of evidence-based interventions to real-world settings, should include representative study sites and staff to improve external validity. Sites for such studies are, however, often selected by convenience sampling, which limits generalizability. We used an optimized probability sampling protocol to select an unbiased, representative sample of study sites to prepare for a randomized trial of a weight loss intervention. We invited North Carolina health departments within 200 miles of the research center to participate (N = 81). Of the 43 health departments that were eligible, 30 were interested in participating. To select a representative and feasible sample of 6 health departments that met inclusion criteria, we generated all combinations of 6 from the 30 health departments that were eligible and interested. From the subset of combinations that met inclusion criteria, we selected 1 at random. Of 593,775 possible combinations of 6 counties, 15,177 (3%) met inclusion criteria. Sites in the selected subset were similar to all eligible sites in terms of health department characteristics and county demographics. Optimized probability sampling improved generalizability by ensuring an unbiased and representative sample of study sites.

A comparison of four-sample slope-intercept and single-sample 51Cr-EDTA glomerular filtration rate measurements.

PubMed

Porter, Charlotte A; Bradley, Kevin M; McGowan, Daniel R

2018-05-01

The aim of this study was to verify, with a large dataset of 1394 Cr-EDTA glomerular filtration rate (GFR) studies, the equivalence of slope-intercept and single-sample GFR. Raw data from 1394 patient studies were used to calculate four-sample slope-intercept GFR in addition to four individual single-sample GFR values (blood samples taken at 90, 150, 210 and 270 min after injection). The percentage differences between the four-sample slope-intercept and each of the single-sample GFR values were calculated, to identify the optimum single-sample time point. Having identified the optimum time point, the percentage difference between the slope-intercept and optimal single-sample GFR was calculated across a range of GFR values to investigate whether there was a GFR value below which the two methodologies cannot be considered equivalent. It was found that the lowest percentage difference between slope-intercept and single-sample GFR was for the third blood sample, taken at 210 min after injection. The median percentage difference was 2.5% and only 6.9% of patient studies had a percentage difference greater than 10%. Above a GFR value of 30 ml/min/1.73 m, the median percentage difference between the slope-intercept and optimal single-sample GFR values was below 10%, and so it was concluded that, above this value, the two techniques are sufficiently equivalent. This study supports the recommendation of performing single-sample GFR measurements for GFRs greater than 30 ml/min/1.73 m.

Volunteer Functions Inventory: A systematic review.

PubMed

Chacón, Fernando; Gutiérrez, Gema; Sauto, Verónica; Vecina, María L; Pérez, Alfonso

2017-08-01

The objective of this research study was to conduct a systematic review of the research on volunteers using Clary et al.’s VFI (1998). A total of 48 research studies including 67 independent samples met eligibility criteria. The total sample of the studies analyzed ranged from 20375 to 21988 participants, depending on the motivation analyzed. The results show that the Values factor obtained the highest mean score, both overall and in each type of volunteering, whereas the lowest scores were for the Career and Enhancement factors. Studies conducted with samples with a mean age under 40 years obtain higher scores on Career and Understanding scales when compared to studies in older samples. The group of studies with less than 50% women yield higher mean scores on the Social scale than studies with more than 50% women in the sample. All the scales show reliability coefficients between .78 and .84. Only eight of the articles provide data on the reliability of the scale with a mean value of .90. Of the 26 studies that performed factor analysis, 18 confirmed the original structure of six factors.

Review of sampling, sample and data collection procedures in nursing research--An example of research on ethical climate as perceived by nurses.

PubMed

Suhonen, Riitta; Stolt, Minna; Katajisto, Jouko; Leino-Kilpi, Helena

2015-12-01

To report a review of quality regarding sampling, sample and data collection procedures of empirical nursing research of ethical climate studies where nurses were informants. Surveys are needed to obtain generalisable information about topics sensitive to nursing. Methodological quality of the studies is of key concern, especially the description of sampling and data collection procedures. Methodological literature review. Using the electronic MEDLINE database, empirical nursing research articles focusing on ethical climate were accessed in 2013 (earliest-22 November 2013). Using the search terms 'ethical' AND ('climate*' OR 'environment*') AND ('nurse*' OR 'nursing'), 376 citations were retrieved. Based on a four-phase retrieval process, 26 studies were included in the detailed analysis. Sampling method was reported in 58% of the studies, and it was random in a minority of the studies (26%). The identification of target sample and its size (92%) was reported, whereas justification for sample size was less often given. In over two-thirds (69%) of the studies with identifiable response rate, it was below 75%. A variety of data collection procedures were used with large amount of missing data about the details of who distributed, recruited and collected the questionnaires. Methods to increase response rates were seldom described. Discussion about nonresponse, representativeness of the sample and generalisability of the results was missing in many studies. This review highlights the methodological challenges and developments that need to be considered in ensuring the use of valid information in developing health care through research findings. © 2015 Nordic College of Caring Science.

Time-of-travel data for Nebraska streams, 1968 to 1977

USGS Publications Warehouse

Petri, L.R.

1984-01-01

This report documents the results of 10 time-of-travel studies, using ' dye-tracer ' methods, conducted on five streams in Nebraska during the period 1968 to 1977. Streams involved in the studies were the North Platte, North Loup, Elkhorn, and Big Blue Rivers and Salt Creek. Rhodamine WT dye in a 20 percent solution was used as the tracer for all 10 time-of-travel studies. Water samples were collected at several points below each injection site. Concentrations of dye in the samples were measured by determining fluorescence of the sample and comparing that value to fluorescence-concentration curves. Stream discharges were measured before and during each study. Results of each time-by-travel study are shown on two tables and on graph. The first table shows water discharge at injection and sampling sites, distance between sites, and time and rate of travel of the dye between sites. The second table provides descriptions of study sites, amounts of dye injected in the streams, actual sampling times, and actual concentrations of dye detected. The graphs for each time-of-travel study provide indications of changing travel rates between sampling sites, information on length of dye clouds, and times for dye passage past given points. (USGS)

Maps showing water geochemistry of the Buffalo Peaks Wilderness Study Area, Lake, Park, and Chaffee Counties, Colorado

USGS Publications Warehouse

Nowlan, G.A.; Ficklin, Walter H.; Dover, Robert A.

1985-01-01

This report presents results of geochemical studies carried out in June and July of 1982 in the Buffalo Peaks Wilderness Study Area, Colo. (see index map). Samples of water were collected from 84 streams and 18 springs draining the study area. Tabulations of the analyses and a sample locality map are in Ficklin and others (1984). The geochemistry of stream sediments and panned concentrates of the study area is in Nowlan and Gerstel (1985). The geology of the study area and vicinity is in Hedlund (1985). The mineral resource potential of the study area is described in Hedlund and others (1983). This report (1) assists in the assessment of the mineral resource potential of the Buffalo Peaks Wilderness Study Area; and (2) compares analyses of water samples with analyses of stream-sediment and panned-concentrate samples (Nowlan and Gerstel, 1985).

Statistical methods for efficient design of community surveys of response to noise: Random coefficients regression models

NASA Technical Reports Server (NTRS)

Tomberlin, T. J.

1985-01-01

Research studies of residents' responses to noise consist of interviews with samples of individuals who are drawn from a number of different compact study areas. The statistical techniques developed provide a basis for those sample design decisions. These techniques are suitable for a wide range of sample survey applications. A sample may consist of a random sample of residents selected from a sample of compact study areas, or in a more complex design, of a sample of residents selected from a sample of larger areas (e.g., cities). The techniques may be applied to estimates of the effects on annoyance of noise level, numbers of noise events, the time-of-day of the events, ambient noise levels, or other factors. Methods are provided for determining, in advance, how accurately these effects can be estimated for different sample sizes and study designs. Using a simple cost function, they also provide for optimum allocation of the sample across the stages of the design for estimating these effects. These techniques are developed via a regression model in which the regression coefficients are assumed to be random, with components of variance associated with the various stages of a multi-stage sample design.

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.

FIELD-SCALE STUDIES: HOW DOES SOIL SAMPLE PRETREATMENT AFFECT REPRESENTATIVENESS ? (ABSTRACT)

EPA Science Inventory

Samples from field-scale studies are very heterogeneous and can contain large soil and rock particles. Oversize materials are often removed before chemical analysis of the soil samples because it is not practical to include these materials. Is the extracted sample representativ...

FIELD-SCALE STUDIES: HOW DOES SOIL SAMPLE PRETREATMENT AFFECT REPRESENTATIVENESS?

EPA Science Inventory

Samples from field-scale studies are very heterogeneous and can contain large soil and rock particles. Oversize materials are often removed before chemical analysis of the soil samples because it is not practical to include these materials. Is the extracted sample representativ...

The Effects of Finite Sampling on State Assessment Sample Requirements. NAEP Validity Studies. Working Paper Series.

ERIC Educational Resources Information Center

Chromy, James R.

This study addressed statistical techniques that might ameliorate some of the sampling problems currently facing states with small populations participating in State National Assessment of Educational Progress (NAEP) assessments. The study explored how the application of finite population correction factors to the between-school component of…

Teacher Efficacy Beliefs: A Case Study Investigation of Core Curriculum

ERIC Educational Resources Information Center

Brown, Natalie Marie

2017-01-01

The purpose of this qualitative case study was to understand how utilizing the Core Knowledge Sequence and aligned curricular resources influenced teachers' perceived self-efficacy for a sample of Arizona elementary charter school teachers. The sample for this study was a convenience sample of 15 elementary teachers, who were currently…

Integrating prospective longitudinal data: modeling personality and health in the Terman Life Cycle and Hawaii Longitudinal Studies.

PubMed

Kern, Margaret L; Hampson, Sarah E; Goldberg, Lewis R; Friedman, Howard S

2014-05-01

The present study used a collaborative framework to integrate 2 long-term prospective studies: the Terman Life Cycle Study and the Hawaii Personality and Health Longitudinal Study. Within a 5-factor personality-trait framework, teacher assessments of child personality were rationally and empirically aligned to establish similar factor structures across samples. Comparable items related to adult self-rated health, education, and alcohol use were harmonized, and data were pooled on harmonized items. A structural model was estimated as a multigroup analysis. Harmonized child personality factors were then used to examine markers of physiological dysfunction in the Hawaii sample and mortality risk in the Terman sample. Harmonized conscientiousness predicted less physiological dysfunction in the Hawaii sample and lower mortality risk in the Terman sample. These results illustrate how collaborative, integrative work with multiple samples offers the exciting possibility that samples from different cohorts and ages can be linked together to directly test life span theories of personality and health. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Validation sampling can reduce bias in health care database studies: an illustration using influenza vaccination effectiveness.

PubMed

Nelson, Jennifer Clark; Marsh, Tracey; Lumley, Thomas; Larson, Eric B; Jackson, Lisa A; Jackson, Michael L

2013-08-01

Estimates of treatment effectiveness in epidemiologic studies using large observational health care databases may be biased owing to inaccurate or incomplete information on important confounders. Study methods that collect and incorporate more comprehensive confounder data on a validation cohort may reduce confounding bias. We applied two such methods, namely imputation and reweighting, to Group Health administrative data (full sample) supplemented by more detailed confounder data from the Adult Changes in Thought study (validation sample). We used influenza vaccination effectiveness (with an unexposed comparator group) as an example and evaluated each method's ability to reduce bias using the control time period before influenza circulation. Both methods reduced, but did not completely eliminate, the bias compared with traditional effectiveness estimates that do not use the validation sample confounders. Although these results support the use of validation sampling methods to improve the accuracy of comparative effectiveness findings from health care database studies, they also illustrate that the success of such methods depends on many factors, including the ability to measure important confounders in a representative and large enough validation sample, the comparability of the full sample and validation sample, and the accuracy with which the data can be imputed or reweighted using the additional validation sample information. Copyright © 2013 Elsevier Inc. All rights reserved.

Designing occupancy studies: general advice and allocating survey effort

USGS Publications Warehouse

MacKenzie, D.I.; Royle, J. Andrew

2005-01-01

1. The fraction of sampling units in a landscape where a target species is present (occupancy) is an extensively used concept in ecology. Yet in many applications the species will not always be detected in a sampling unit even when present, resulting in biased estimates of occupancy. Given that sampling units are surveyed repeatedly within a relatively short timeframe, a number of similar methods have now been developed to provide unbiased occupancy estimates. However, practical guidance on the efficient design of occupancy studies has been lacking. 2. In this paper we comment on a number of general issues related to designing occupancy studies, including the need for clear objectives that are explicitly linked to science or management, selection of sampling units, timing of repeat surveys and allocation of survey effort. Advice on the number of repeat surveys per sampling unit is considered in terms of the variance of the occupancy estimator, for three possible study designs. 3. We recommend that sampling units should be surveyed a minimum of three times when detection probability is high (> 0.5 survey-1), unless a removal design is used. 4. We found that an optimal removal design will generally be the most efficient, but we suggest it may be less robust to assumption violations than a standard design. 5. Our results suggest that for a rare species it is more efficient to survey more sampling units less intensively, while for a common species fewer sampling units should be surveyed more intensively. 6. Synthesis and applications. Reliable inferences can only result from quality data. To make the best use of logistical resources, study objectives must be clearly defined; sampling units must be selected, and repeated surveys timed appropriately; and a sufficient number of repeated surveys must be conducted. Failure to do so may compromise the integrity of the study. The guidance given here on study design issues is particularly applicable to studies of species occurrence and distribution, habitat selection and modelling, metapopulation studies and monitoring programmes.

Detecting spatial structures in throughfall data: the effect of extent, sample size, sampling design, and variogram estimation method

NASA Astrophysics Data System (ADS)

Voss, Sebastian; Zimmermann, Beate; Zimmermann, Alexander

2016-04-01

In the last three decades, an increasing number of studies analyzed spatial patterns in throughfall to investigate the consequences of rainfall redistribution for biogeochemical and hydrological processes in forests. In the majority of cases, variograms were used to characterize the spatial properties of the throughfall data. The estimation of the variogram from sample data requires an appropriate sampling scheme: most importantly, a large sample and an appropriate layout of sampling locations that often has to serve both variogram estimation and geostatistical prediction. While some recommendations on these aspects exist, they focus on Gaussian data and high ratios of the variogram range to the extent of the study area. However, many hydrological data, and throughfall data in particular, do not follow a Gaussian distribution. In this study, we examined the effect of extent, sample size, sampling design, and calculation methods on variogram estimation of throughfall data. For our investigation, we first generated non-Gaussian random fields based on throughfall data with heavy outliers. Subsequently, we sampled the fields with three extents (plots with edge lengths of 25 m, 50 m, and 100 m), four common sampling designs (two grid-based layouts, transect and random sampling), and five sample sizes (50, 100, 150, 200, 400). We then estimated the variogram parameters by method-of-moments and residual maximum likelihood. Our key findings are threefold. First, the choice of the extent has a substantial influence on the estimation of the variogram. A comparatively small ratio of the extent to the correlation length is beneficial for variogram estimation. Second, a combination of a minimum sample size of 150, a design that ensures the sampling of small distances and variogram estimation by residual maximum likelihood offers a good compromise between accuracy and efficiency. Third, studies relying on method-of-moments based variogram estimation may have to employ at least 200 sampling points for reliable variogram estimates. These suggested sample sizes exceed the numbers recommended by studies dealing with Gaussian data by up to 100 %. Given that most previous throughfall studies relied on method-of-moments variogram estimation and sample sizes << 200, our current knowledge about throughfall spatial variability stands on shaky ground.

Detecting spatial structures in throughfall data: The effect of extent, sample size, sampling design, and variogram estimation method

NASA Astrophysics Data System (ADS)

Voss, Sebastian; Zimmermann, Beate; Zimmermann, Alexander

2016-09-01

In the last decades, an increasing number of studies analyzed spatial patterns in throughfall by means of variograms. The estimation of the variogram from sample data requires an appropriate sampling scheme: most importantly, a large sample and a layout of sampling locations that often has to serve both variogram estimation and geostatistical prediction. While some recommendations on these aspects exist, they focus on Gaussian data and high ratios of the variogram range to the extent of the study area. However, many hydrological data, and throughfall data in particular, do not follow a Gaussian distribution. In this study, we examined the effect of extent, sample size, sampling design, and calculation method on variogram estimation of throughfall data. For our investigation, we first generated non-Gaussian random fields based on throughfall data with large outliers. Subsequently, we sampled the fields with three extents (plots with edge lengths of 25 m, 50 m, and 100 m), four common sampling designs (two grid-based layouts, transect and random sampling) and five sample sizes (50, 100, 150, 200, 400). We then estimated the variogram parameters by method-of-moments (non-robust and robust estimators) and residual maximum likelihood. Our key findings are threefold. First, the choice of the extent has a substantial influence on the estimation of the variogram. A comparatively small ratio of the extent to the correlation length is beneficial for variogram estimation. Second, a combination of a minimum sample size of 150, a design that ensures the sampling of small distances and variogram estimation by residual maximum likelihood offers a good compromise between accuracy and efficiency. Third, studies relying on method-of-moments based variogram estimation may have to employ at least 200 sampling points for reliable variogram estimates. These suggested sample sizes exceed the number recommended by studies dealing with Gaussian data by up to 100 %. Given that most previous throughfall studies relied on method-of-moments variogram estimation and sample sizes ≪200, currently available data are prone to large uncertainties.

Population pharmacokinetic modelling of rupatadine solution in 6-11 year olds and optimisation of the experimental design in younger children.

PubMed

Santamaría, Eva; Estévez, Javier Alejandro; Riba, Jordi; Izquierdo, Iñaki; Valle, Marta

2017-01-01

To optimise a pharmacokinetic (PK) study design of rupatadine for 2-5 year olds by using a population PK model developed with data from a study in 6-11 year olds. The design optimisation was driven by the need to avoid children's discomfort in the study. PK data from 6-11 year olds with allergic rhinitis available from a previous study were used to construct a population PK model which we used in simulations to assess the dose to administer in a study in 2-5 year olds. In addition, an optimal design approach was used to determine the most appropriate number of sampling groups, sampling days, total samples and sampling times. A two-compartmental model with first-order absorption and elimination, with clearance dependent on weight adequately described the PK of rupatadine for 6-11 year olds. The dose selected for a trial in 2-5 year olds was 2.5 mg, as it provided a Cmax below the 3 ng/ml threshold. The optimal study design consisted of four groups of children (10 children each), a maximum sampling window of 2 hours in two clinic visits for drawing three samples on day 14 and one on day 28 coinciding with the final examination of the study. A PK study design was optimised in order to prioritise avoidance of discomfort for enrolled 2-5 year olds by taking only four blood samples from each child and minimising the length of hospital stays.

Effect of Different Sampling Schedules on Results of Bioavailability and Bioequivalence Studies: Evaluation by Means of Monte Carlo Simulations.

PubMed

Kano, Eunice Kazue; Chiann, Chang; Fukuda, Kazuo; Porta, Valentina

2017-08-01

Bioavailability and bioequivalence study is one of the most frequently performed investigations in clinical trials. Bioequivalence testing is based on the assumption that 2 drug products will be therapeutically equivalent when they are equivalent in the rate and extent to which the active drug ingredient or therapeutic moiety is absorbed and becomes available at the site of drug action. In recent years there has been a significant growth in published papers that use in silico studies based on mathematical simulations to analyze pharmacokinetic and pharmacodynamic properties of drugs, including bioavailability and bioequivalence aspects. The goal of this study is to evaluate the usefulness of in silico studies as a tool in the planning of bioequivalence, bioavailability and other pharmacokinetic assays, e.g., to determine an appropriate sampling schedule. Monte Carlo simulations were used to define adequate blood sampling schedules for a bioequivalence assay comparing 2 different formulations of cefadroxil oral suspensions. In silico bioequivalence studies comparing different formulation of cefadroxil oral suspensions using various sampling schedules were performed using models. An in vivo study was conducted to confirm in silico results. The results of in silico and in vivo bioequivalence studies demonstrated that schedules with fewer sampling times are as efficient as schedules with larger numbers of sampling times in the assessment of bioequivalence, but only if T max is included as a sampling time. It was also concluded that in silico studies are useful tools in the planning of bioequivalence, bioavailability and other pharmacokinetic in vivo assays. © Georg Thieme Verlag KG Stuttgart · New York.

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.

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

Comparison of stool collection on site versus at home in a population-based study : feasibility and participants' preference in Pretest 2 of the German National Cohort.

PubMed

Schultze, A; Akmatov, M K; Andrzejak, M; Karras, N; Kemmling, Y; Maulhardt, A; Wieghold, S; Ahrens, W; Günther, K; Schlenz, H; Krause, G; Pessler, F

2014-11-01

For certain laboratory investigations it is necessary to obtain native stool samples and process them within a narrow time window at the point of contact or a nearby laboratory. However, it is not known whether it is feasible to obtain stool samples from asymptomatic individuals during an appointment in a study center (SC). We therefore compared participants' preference, feasibility and acceptance of stool sample collection during the appointment at the study center (on-site sampling) to collection at home after the appointment. The study was conducted at two sites in Northern Germany (Bremen, n = 156; Hannover, n = 147) during the Pretest 2 phase of the German National Cohort (GNC), drawing upon a randomly selected population supplemented by a small convenience sample. In the study center, the participants were given the choice to provide a stool sample during the appointment or to collect a sample later at home and return it by mail. In all, 303 of the 351 participants (86 %) of Pretest 2 at these sites participated in this feasibility study. Only 7.9 % (24/303) of the participants chose on-site collection, whereas 92 % (279/303) chose at-home collection. There were significant differences between the two study sites in that 14 % (21/147) of participants in Hannover and 2 % (3/156) of participants in Bremen chose on-site collection. Compliance was high in both groups, as 100 % (24/24) and 98 % (272/279) of participants in the on-site and at-home groups, respectively, provided complete samples. Both methods were highly accepted, as 92 % of the participants in each group (22/24 and 227/248) stated that stool collection at the respective site was acceptable. When given a choice, most participants in this population-based study preferred home collection of stool samples to collection in the study center. Thus, native stool samples for immediate processing in the study center may potentially be obtained only from a subpopulation of participants, which may lead to selection bias. Home collection, on the other hand, proved to be a highly feasible method for studies that do not require freshly collected native stool.

Optimum sample size allocation to minimize cost or maximize power for the two-sample trimmed mean test.

PubMed

Guo, Jiin-Huarng; Luh, Wei-Ming

2009-05-01

When planning a study, sample size determination is one of the most important tasks facing the researcher. The size will depend on the purpose of the study, the cost limitations, and the nature of the data. By specifying the standard deviation ratio and/or the sample size ratio, the present study considers the problem of heterogeneous variances and non-normality for Yuen's two-group test and develops sample size formulas to minimize the total cost or maximize the power of the test. For a given power, the sample size allocation ratio can be manipulated so that the proposed formulas can minimize the total cost, the total sample size, or the sum of total sample size and total cost. On the other hand, for a given total cost, the optimum sample size allocation ratio can maximize the statistical power of the test. After the sample size is determined, the present simulation applies Yuen's test to the sample generated, and then the procedure is validated in terms of Type I errors and power. Simulation results show that the proposed formulas can control Type I errors and achieve the desired power under the various conditions specified. Finally, the implications for determining sample sizes in experimental studies and future research are discussed.

Comparing identified and statistically significant lipids and polar metabolites in 15-year old serum and dried blood spot samples for longitudinal studies: Comparing lipids and metabolites in serum and DBS samples

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

Kyle, Jennifer E.; Casey, Cameron P.; Stratton, Kelly G.

The use of dried blood spots (DBS) has many advantages over traditional plasma and serum samples such as smaller blood volume required, storage at room temperature, and ability for sampling in remote locations. However, understanding the robustness of different analytes in DBS samples is essential, especially in older samples collected for longitudinal studies. Here we analyzed DBS samples collected in 2000-2001 and stored at room temperature and compared them to matched serum samples stored at -80°C to determine if they could be effectively used as specific time points in a longitudinal study following metabolic disease. Four hundred small molecules weremore » identified in both the serum and DBS samples using gas chromatograph-mass spectrometry (GC-MS), liquid chromatography-MS (LC-MS) and LC-ion mobility spectrometry-MS (LC-IMS-MS). The identified polar metabolites overlapped well between the sample types, though only one statistically significant polar metabolite in a case-control study was conserved, indicating degradation occurs in the DBS samples affecting quantitation. Differences in the lipid identifications indicated that some oxidation occurs in the DBS samples. However, thirty-six statistically significant lipids correlated in both sample types indicating that lipid quantitation was more stable across the sample types.« less

Culture-independent analysis of hydrocarbonoclastic bacterial communities in environmental samples during oil-bioremediation.

PubMed

Dashti, Narjes; Ali, Nedaa; Salamah, Samar; Khanafer, Majida; Al-Shamy, Ghada; Al-Awadhi, Husain; Radwan, Samir S

2018-04-15

To analyze microbial communities in environmental samples, this study combined Denaturing Gradient Gel Electrophoresis of amplified 16S rRNA-genes in total genomic DNA extracts from those samples with gene sequencing. The environmental samples studied were oily seawater and soil samples, that had been bioaugmented with natural materials rich in hydrocarbonoclastic bacteria. This molecular approach revealed much more diverse bacterial taxa than the culture-dependent method we had used in an earlier study for the analysis of the same samples. The study described the dynamics of bacterial communities during bioremediation. The main limitation associated with this molecular approach, namely of not distinguishing hydrocarbonoclastic taxa from others, was overcome by consulting the literature for the hydrocarbonoclastic potential of taxa related to those identified in this study. By doing so, it was concluded that the hydrocarbonoclastic bacterial taxa were much more diverse than those captured by the culture-dependent approach. The molecular analysis also revealed the frequent occurrence of nifH-genes in the total genomic DNA extracts of all the studied environmental samples, which reflects a nitrogen-fixation potential. Nitrogen fertilization is long known to enhance microbial oil-bioremediation. The study revealed that bioaugmentation using plant rhizospheres or soil with long history of oil-pollution was more effective in oil-removal in the desert soil than in seawater microcosms. © 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Sample size considerations for paired experimental design with incomplete observations of continuous outcomes.

PubMed

Zhu, Hong; Xu, Xiaohan; Ahn, Chul

2017-01-01

Paired experimental design is widely used in clinical and health behavioral studies, where each study unit contributes a pair of observations. Investigators often encounter incomplete observations of paired outcomes in the data collected. Some study units contribute complete pairs of observations, while the others contribute either pre- or post-intervention observations. Statistical inference for paired experimental design with incomplete observations of continuous outcomes has been extensively studied in literature. However, sample size method for such study design is sparsely available. We derive a closed-form sample size formula based on the generalized estimating equation approach by treating the incomplete observations as missing data in a linear model. The proposed method properly accounts for the impact of mixed structure of observed data: a combination of paired and unpaired outcomes. The sample size formula is flexible to accommodate different missing patterns, magnitude of missingness, and correlation parameter values. We demonstrate that under complete observations, the proposed generalized estimating equation sample size estimate is the same as that based on the paired t-test. In the presence of missing data, the proposed method would lead to a more accurate sample size estimate comparing with the crude adjustment. Simulation studies are conducted to evaluate the finite-sample performance of the generalized estimating equation sample size formula. A real application example is presented for illustration.

Sampling design and procedures for fixed surface-water sites in the Georgia-Florida coastal plain study unit, 1993

USGS Publications Warehouse

Hatzell, H.H.; Oaksford, E.T.; Asbury, C.E.

1995-01-01

The implementation of design guidelines for the National Water-Quality Assessment (NAWQA) Program has resulted in the development of new sampling procedures and the modification of existing procedures commonly used in the Water Resources Division of the U.S. Geological Survey. The Georgia-Florida Coastal Plain (GAFL) study unit began the intensive data collection phase of the program in October 1992. This report documents the implementation of the NAWQA guidelines by describing the sampling design and procedures for collecting surface-water samples in the GAFL study unit in 1993. This documentation is provided for agencies that use water-quality data and for future study units that will be entering the intensive phase of data collection. The sampling design is intended to account for large- and small-scale spatial variations, and temporal variations in water quality for the study area. Nine fixed sites were selected in drainage basins of different sizes and different land-use characteristics located in different land-resource provinces. Each of the nine fixed sites was sampled regularly for a combination of six constituent groups composed of physical and chemical constituents: field measurements, major ions and metals, nutrients, organic carbon, pesticides, and suspended sediments. Some sites were also sampled during high-flow conditions and storm events. Discussion of the sampling procedure is divided into three phases: sample collection, sample splitting, and sample processing. A cone splitter was used to split water samples for the analysis of the sampling constituent groups except organic carbon from approximately nine liters of stream water collected at four fixed sites that were sampled intensively. An example of the sample splitting schemes designed to provide the sample volumes required for each sample constituent group is described in detail. Information about onsite sample processing has been organized into a flowchart that describes a pathway for each of the constituent groups.

RECRUITING FOR A LONGITUDINAL STUDY OF CHILDREN'S HEALTH USING A HOUSEHOLD-BASED PROBABILITY SAMPLING APPROACH

EPA Science Inventory

The sampling design for the National Children¿s Study (NCS) calls for a population-based, multi-stage, clustered household sampling approach (visit our website for more information on the NCS : www.nationalchildrensstudy.gov). The full sample is designed to be representative of ...

NHEXAS PHASE I ARIZONA STUDY--METALS IN BLOOD ANALYTICAL RESULTS

EPA Science Inventory

The Metals in Blood data set contains analytical results for measurements of up to 2 metals in 165 blood samples over 165 households. Each sample was collected as a venous sample from the primary respondent within each household during Stage III of the NHEXAS study. The samples...

Does Cognitive Function Increase over Time in the Healthy Elderly?

PubMed Central

de Rotrou, Jocelyne; Wu, Ya-Huei; Mabire, Jean-Bernard; Moulin, Florence; de Jong, Laura W.; Rigaud, Anne-Sophie; Hanon, Olivier; Vidal, Jean-Sébastien

2013-01-01

Background In dementia screening, most studies have focused on early cognitive impairment by comparing patients suffering from mild dementia or mild cognitive impairment with normal subjects. Few studies have focused on modifications over time of the cognitive function in the healthy elderly. The objective of the present study was to analyze the cognitive function changes of two different samples, born > 15 years apart. Method A first sample of 204 cognitively normal participants was recruited in the memory clinic of Broca hospital between 1991 and 1997. A second sample of 177 cognitively normal participants was recruited in 2008–2009 in the same institution. Both samples were from the same districts of Paris and were assessed with the same neuropsychological test battery. Mean cognitive test scores were compared between 1991 and 2008 samples, between < 80 years old and ≥ 80 years old in 1991 and 2008 samples, and finally between subjects < 80 year old of 1991 sample and subjects ≥ 80 years old of the 2008 sample. Means were compared with T-tests stratified on gender, age-groups and educational level. Results Cognitive scores were significantly higher in the 2008 sample. Participants < 80 years old outperformed those ≥ 80 in both samples. However, participants < 80 years old in 1991 sample and subjects ≥ 80 in the 2008 sample, born on average in 1923, performed mostly identically. Conclusion This study showed a significant increase of cognitive scores over time. Further, contemporary octogenarians in the later sample performed like septuagenarians in the former sample. These findings might be consistent with the increase in life expectancy and life span in good health. The study highlights the necessity to take into account factors which may contaminate and artificially inflate the age-related differences in favor of younger to the older adults. PMID:24244332

Sample size determination for estimating antibody seroconversion rate under stable malaria transmission intensity.

PubMed

Sepúlveda, Nuno; Drakeley, Chris

2015-04-03

In the last decade, several epidemiological studies have demonstrated the potential of using seroprevalence (SP) and seroconversion rate (SCR) as informative indicators of malaria burden in low transmission settings or in populations on the cusp of elimination. However, most of studies are designed to control ensuing statistical inference over parasite rates and not on these alternative malaria burden measures. SP is in essence a proportion and, thus, many methods exist for the respective sample size determination. In contrast, designing a study where SCR is the primary endpoint, is not an easy task because precision and statistical power are affected by the age distribution of a given population. Two sample size calculators for SCR estimation are proposed. The first one consists of transforming the confidence interval for SP into the corresponding one for SCR given a known seroreversion rate (SRR). The second calculator extends the previous one to the most common situation where SRR is unknown. In this situation, data simulation was used together with linear regression in order to study the expected relationship between sample size and precision. The performance of the first sample size calculator was studied in terms of the coverage of the confidence intervals for SCR. The results pointed out to eventual problems of under or over coverage for sample sizes ≤250 in very low and high malaria transmission settings (SCR ≤ 0.0036 and SCR ≥ 0.29, respectively). The correct coverage was obtained for the remaining transmission intensities with sample sizes ≥ 50. Sample size determination was then carried out for cross-sectional surveys using realistic SCRs from past sero-epidemiological studies and typical age distributions from African and non-African populations. For SCR < 0.058, African studies require a larger sample size than their non-African counterparts in order to obtain the same precision. The opposite happens for the remaining transmission intensities. With respect to the second sample size calculator, simulation unravelled the likelihood of not having enough information to estimate SRR in low transmission settings (SCR ≤ 0.0108). In that case, the respective estimates tend to underestimate the true SCR. This problem is minimized by sample sizes of no less than 500 individuals. The sample sizes determined by this second method highlighted the prior expectation that, when SRR is not known, sample sizes are increased in relation to the situation of a known SRR. In contrast to the first sample size calculation, African studies would now require lesser individuals than their counterparts conducted elsewhere, irrespective of the transmission intensity. Although the proposed sample size calculators can be instrumental to design future cross-sectional surveys, the choice of a particular sample size must be seen as a much broader exercise that involves weighting statistical precision with ethical issues, available human and economic resources, and possible time constraints. Moreover, if the sample size determination is carried out on varying transmission intensities, as done here, the respective sample sizes can also be used in studies comparing sites with different malaria transmission intensities. In conclusion, the proposed sample size calculators are a step towards the design of better sero-epidemiological studies. Their basic ideas show promise to be applied to the planning of alternative sampling schemes that may target or oversample specific age groups.

Results from a Survey of Current Practices for Sampling of Nervous System in Rodents and Non-rodents in General Toxicity Studies

EPA Science Inventory

A survey of current practices for sampling and examination of the nervous system in rodents and non-rodents for general and neurotoxicity (NT) studies was conducted by the Nervous System Sampling Subcommittee of the STP. For general toxicity studies most of those surveyed (>63%) ...

The Generation R Study: Biobank update 2015.

PubMed

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

2014-12-01

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

Insights from two industrial hygiene pilot e-cigarette passive vaping studies.

PubMed

Maloney, John C; Thompson, Michael K; Oldham, Michael J; Stiff, Charles L; Lilly, Patrick D; Patskan, George J; Shafer, Kenneth H; Sarkar, Mohamadi A

2016-01-01

While several reports have been published using research methods of estimating exposure risk to e-cigarette vapors in nonusers, only two have directly measured indoor air concentrations from vaping using validated industrial hygiene sampling methodology. Our first study was designed to measure indoor air concentrations of nicotine, menthol, propylene glycol, glycerol, and total particulates during the use of multiple e-cigarettes in a well-characterized room over a period of time. Our second study was a repeat of the first study, and it also evaluated levels of formaldehyde. Measurements were collected using active sampling, near real-time and direct measurement techniques. Air sampling incorporated industrial hygiene sampling methodology using analytical methods established by the National Institute of Occupational Safety and Health and the Occupational Safety and Health Administration. Active samples were collected over a 12-hr period, for 4 days. Background measurements were taken in the same room the day before and the day after vaping. Panelists (n = 185 Study 1; n = 145 Study 2) used menthol and non-menthol MarkTen prototype e-cigarettes. Vaping sessions (six, 1-hr) included 3 prototypes, with total number of puffs ranging from 36-216 per session. Results of the active samples were below the limit of quantitation of the analytical methods. Near real-time data were below the lowest concentration on the established calibration curves. Data from this study indicate that the majority of chemical constituents sampled were below quantifiable levels. Formaldehyde was detected at consistent levels during all sampling periods. These two studies found that indoor vaping of MarkTen prototype e-cigarette does not produce chemical constituents at quantifiable levels or background levels using standard industrial hygiene collection techniques and analytical methods.

Evaluation of Buccal Cell Samples for Studies of Oral Microbiota.

PubMed

Yu, Guoqin; Phillips, Steve; Gail, Mitchell H; Goedert, James J; Humphrys, Michael; Ravel, Jacques; Ren, Yanfang; Caporaso, Neil E

2017-02-01

The human microbiota is postulated to affect cancer risk, but collecting microbiota specimens with prospective follow-up for diseases will take time. Buccal cell samples have been obtained from mouthwash for the study of human genomic DNA in many cohort studies. Here, we evaluate the feasibility of using buccal cell samples to examine associations of human microbiota and disease risk. We obtained buccal cells from mouthwash in 41 healthy participants using a protocol that is widely employed to obtain buccal cells for the study of human DNA. We compared oral microbiota from buccal cells with that from eight other oral sample types collected by following the protocols of the Human Microbiome Project. Microbiota profiles were determined by sequencing 16S rRNA gene V3-V4 region. Compared with each of the eight other oral samples, the buccal cell samples had significantly more observed species (P < 0.002) and higher alpha diversity (Shannon index, P < 0.02). The microbial communities were more similar (smaller beta diversity) among buccal cells samples than in the other samples (P < 0.001 for 12 of 16 weighted and unweighted UniFrac distance comparisons). Buccal cell microbial profiles closely resembled saliva but were distinct from dental plaque and tongue dorsum. Stored buccal cell samples in prospective cohort studies are a promising resource to study associations of oral microbiota with disease. The feasibility of using existing buccal cell collections in large prospective cohorts allows investigations of the role of oral microbiota in chronic disease etiology in large population studies possible today. Cancer Epidemiol Biomarkers Prev; 26(2); 249-53. ©2016 AACR. ©2016 American Association for Cancer Research.

Opinions of Teachers and Preservice Teachers of Social Studies on Geo-Literacy

ERIC Educational Resources Information Center

Memisoglu, Hatice

2017-01-01

The purpose of this study is to investigate the opinions of teachers and preservice teachers of social studies on geo-literacy. The study used the qualitative research design of phenomenology to collect data. The study consisted of 20 teachers and 30 prospective teachers of social studies. The purposive sampling method of criterion sampling was…

Reproducibility of preclinical animal research improves with heterogeneity of study samples

PubMed Central

Vogt, Lucile; Sena, Emily S.; Würbel, Hanno

2018-01-01

Single-laboratory studies conducted under highly standardized conditions are the gold standard in preclinical animal research. Using simulations based on 440 preclinical studies across 13 different interventions in animal models of stroke, myocardial infarction, and breast cancer, we compared the accuracy of effect size estimates between single-laboratory and multi-laboratory study designs. Single-laboratory studies generally failed to predict effect size accurately, and larger sample sizes rendered effect size estimates even less accurate. By contrast, multi-laboratory designs including as few as 2 to 4 laboratories increased coverage probability by up to 42 percentage points without a need for larger sample sizes. These findings demonstrate that within-study standardization is a major cause of poor reproducibility. More representative study samples are required to improve the external validity and reproducibility of preclinical animal research and to prevent wasting animals and resources for inconclusive research. PMID:29470495

Groundwater-quality data in 12 GAMA study units: Results from the 2006–10 initial sampling period and the 2008–13 trend sampling period, California GAMA Priority Basin Project

USGS Publications Warehouse

Mathany, Timothy M.

2017-03-09

The Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) program was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey in cooperation with the California State Water Resources Control Board. From 2004 through 2012, the GAMA-PBP collected samples and assessed the quality of groundwater resources that supply public drinking water in 35 study units across the State. Selected sites in each study unit were sampled again approximately 3 years after initial sampling as part of an assessment of temporal trends in water quality by the GAMA-PBP. Twelve of the study units, initially sampled during 2006–11 (initial sampling period) and sampled a second time during 2008–13 (trend sampling period) to assess temporal trends, are the subject of this report.The initial sampling was designed to provide a spatially unbiased assessment of the quality of untreated groundwater used for public water supplies in the 12 study units. In these study units, 550 sampling sites were selected by using a spatially distributed, randomized, grid-based method to provide spatially unbiased representation of the areas assessed (grid sites, also called “status sites”). After the initial sampling period, 76 of the previously sampled status sites (approximately 10 percent in each study unit) were randomly selected for trend sampling (“trend sites”). The 12 study units sampled both during the initial sampling and during the trend sampling period were distributed among 6 hydrogeologic provinces: Coastal (Northern and Southern), Transverse Ranges and Selected Peninsular Ranges, Klamath, Modoc Plateau and Cascades, and Sierra Nevada Hydrogeologic Provinces. For the purposes of this trend report, the six hydrogeologic provinces were grouped into two hydrogeologic regions based on location: Coastal and Mountain.The groundwater samples were analyzed for a number of synthetic organic constituents (volatile organic compounds, pesticides, and pesticide degradates), constituents of special interest (perchlorate and 1,2,3-trichloropropane), and natural inorganic constituents (nutrients, major and minor ions, and trace elements). Isotopic tracers (tritium, carbon-14, and stable isotopes of hydrogen and oxygen in water) also were measured to help identify processes affecting groundwater quality and the sources and ages of the sampled groundwater. More than 200 constituents and water-quality indicators were measured during the trend sampling period.Quality-control samples (blanks, replicates, matrix-spikes, and surrogate compounds) were collected at about one-third of the trend sites, and the results for these samples were used to evaluate the quality of the data for the groundwater samples. On the basis of detections in laboratory and field blank samples collected by GAMA-PBP study units, including the 12 study units presented here, reporting levels for some groundwater results were adjusted in this report. Differences between replicate samples were mostly within acceptable ranges, indicating low variability in analytical results. Matrix-spike recoveries were largely within the acceptable range (70 to 130 percent).This study did not attempt to evaluate the quality of water delivered to consumers. After withdrawal, groundwater used for drinking water typically is treated, disinfected, and blended with other waters to achieve acceptable water quality. The comparison benchmarks used in this report apply to treated water that is served to the consumer, not to untreated groundwater. To provide some context for the results, however, concentrations of constituents measured in these groundwater samples were compared with benchmarks established by the U.S. Environmental Protection Agency and the State of California. Comparisons between data collected for this study and benchmarks for drinking water are for illustrative purposes only and are not indicative of compliance or non-compliance with those benchmarks.Most organic constituents that were detected in groundwater samples from the trend sites were found at concentrations less than health-based benchmarks. One volatile organic compound—perchloroethene—was detected at a concentration greater than the health-based benchmark in samples from one trend site during the initial and trend sampling periods. Chloroform was detected in at least 10 percent of the samples at trend sites in both sampling periods. Methyl tert-butyl ether was detected in samples from more than 10 percent of the trend sites during the initial sampling period. No pesticide or pesticide degradate was detected in greater than 10 percent of the samples from trend sites or at concentrations greater than their health-based benchmarks during either sampling period. Nutrients were not detected at concentrations greater than their health-based benchmarks during either sampling period.Most detections of major ions and trace elements in samples from trend sites were less than health-based benchmarks during both sampling periods. Arsenic and boron each were detected at concentrations greater than the health-based benchmark in samples from four trend sites during the initial and trend sampling periods. Molybdenum was detected in samples from four trend sites at concentrations greater than the health-based benchmark during both sampling periods. Samples from two of these trend sites had similar molybdenum concentrations, and two had substantially different concentrations during the initial and trend sampling periods. Uranium was detected at a concentration greater than the health-based benchmark only at two trend sites.

Sampling guidelines for oral fluid-based surveys of group-housed animals.

PubMed

Rotolo, Marisa L; Sun, Yaxuan; Wang, Chong; Giménez-Lirola, Luis; Baum, David H; Gauger, Phillip C; Harmon, Karen M; Hoogland, Marlin; Main, Rodger; Zimmerman, Jeffrey J

2017-09-01

Formulas and software for calculating sample size for surveys based on individual animal samples are readily available. However, sample size formulas are not available for oral fluids and other aggregate samples that are increasingly used in production settings. Therefore, the objective of this study was to develop sampling guidelines for oral fluid-based porcine reproductive and respiratory syndrome virus (PRRSV) surveys in commercial swine farms. Oral fluid samples were collected in 9 weekly samplings from all pens in 3 barns on one production site beginning shortly after placement of weaned pigs. Samples (n=972) were tested by real-time reverse-transcription PCR (RT-rtPCR) and the binary results analyzed using a piecewise exponential survival model for interval-censored, time-to-event data with misclassification. Thereafter, simulation studies were used to study the barn-level probability of PRRSV detection as a function of sample size, sample allocation (simple random sampling vs fixed spatial sampling), assay diagnostic sensitivity and specificity, and pen-level prevalence. These studies provided estimates of the probability of detection by sample size and within-barn prevalence. Detection using fixed spatial sampling was as good as, or better than, simple random sampling. Sampling multiple barns on a site increased the probability of detection with the number of barns sampled. These results are relevant to PRRSV control or elimination projects at the herd, regional, or national levels, but the results are also broadly applicable to contagious pathogens of swine for which oral fluid tests of equivalent performance are available. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Methodological issues affecting the study of fish parasites. II. Sampling method affects ectoparasite studies.

PubMed

Kvach, Yuriy; Ondračková, Markéta; Janáč, Michal; Jurajda, Pavel

2016-08-31

In this study, we assessed the impact of sampling method on the results of fish ectoparasite studies. Common roach Rutilus rutilus were sampled from the same gravel pit in the River Dyje flood plain (Czech Republic) using 3 different sampling methods, i.e. electrofishing, beach seining and gill-netting, and were examined for ectoparasites. Not only did fish caught by electrofishing have more of the most abundant parasites (Trichodina spp., Gyrodactylus spp.) than those caught by beach seining or gill-netting, they also had relatively rich parasite infracommunities, resulting in a significantly different assemblage composition, presumably as parasites were lost through handling and 'manipulation' in the net. Based on this, we recommend electrofishing as the most suitable method to sample fish for parasite community studies, as data from fish caught with gill-nets and beach seines will provide a biased picture of the ectoparasite community, underestimating ectoparasite abundance and infracommunity species richness.

Big Data and Large Sample Size: A Cautionary Note on the Potential for Bias

PubMed Central

Chambers, David A.; Glasgow, Russell E.

2014-01-01

Abstract A number of commentaries have suggested that large studies are more reliable than smaller studies and there is a growing interest in the analysis of “big data” that integrates information from many thousands of persons and/or different data sources. We consider a variety of biases that are likely in the era of big data, including sampling error, measurement error, multiple comparisons errors, aggregation error, and errors associated with the systematic exclusion of information. Using examples from epidemiology, health services research, studies on determinants of health, and clinical trials, we conclude that it is necessary to exercise greater caution to be sure that big sample size does not lead to big inferential errors. Despite the advantages of big studies, large sample size can magnify the bias associated with error resulting from sampling or study design. Clin Trans Sci 2014; Volume #: 1–5 PMID:25043853

Relationship between Dispositional Mindfulness and Substance Use: Findings from a Clinical Sample

PubMed Central

Bowen, Sarah; Enkema, Matthew C.

2014-01-01

There has been rapidly increasing interest over the past decade in the potential of mindfulness-based approaches to psychological and medical treatment, including a recent growth in the area of substance abuse. Thus, the relationship between trait mindfulness and substance use has been explored in several studies. Results, however, have been mixed. While several studies of college student populations have evinced positive correlations between levels of trait mindfulness and substance use, the opposite seems to be true in clinical samples, with multiple studies showing a negative association. The current study reviews research in both non-treatment seeking college students and in clinical samples, and examines the relationship between trait mindfulness and substance dependence in a clinical sample (N = 281). Further, the study assesses the moderating effect of avoidant coping that might explain the disparate findings in the clinical versus nonclinical samples. PMID:24290208

Zoonoses research in the German National Cohort : feasibility of parallel sampling of pets and owners.

PubMed

Hille, Katja; Möbius, Nadine; Akmatov, Manas K; Verspohl, Jutta; Rabold, Denise; Hartmann, Maria; Günther, Kathrin; Obi, Nadia; Kreienbrock, Lothar

2014-11-01

Cats and dogs live in more than 20 % of German households and the contact between these pets and their owners can be very close. Therefore, a transmission of zoonotic pathogens may occur. To investigate whether zoonotic research questions can be examined in the context of population-based studies like the German National Cohort (GNC), two studies on different study populations were conducted as part of the feasibility tests of the GNC. The aim of the first study was to quantify the actual exposure of participants of the GNC to cats and dogs. In the second study summarised here the feasibility of the sampling of cats and dogs by their owners was tested. To quantify the exposure of participants of the GNC to cats and dogs 744 study participants of the Pretests of the GNC were asked whether they had contact with animals. Currently 10 % have a dog and 14 % have a cat in their household. These figures confirm that a large proportion of the German population has contact with pets and that there is a need for further zoonoses research. To establish the collection of biological samples from cats and dogs in the context of large-scale population-based studies feasible methods are needed. Therefore, a study was conducted to test whether pet owners can take samples from their cats and dogs and whether the quality of these samples is comparable to samples taken by a qualified veterinarian. A total of 82 dog and 18 cat owners were recruited in two veterinary practices in Hannover and the Clinic for Small Animals at the University of Veterinary Medicine in Hannover. Sampling instructions and sample material for nasal and buccal swabs, faecal samples and, in the case of cat owners, a brush for fur samples, were given to the pet owners. The pet owners were asked to take the samples from their pets at home and to send the samples by surface mail. Swab samples were cultured and bacterial growth was quantified independent of bacterial species. The growth of Gram-positive and Gram-negative bacteria from samples taken by the veterinarian and the pet owners were compared. For Gram-positive bacteria the agreement of laboratory results was 71 % for nasal swabs and 78 % for oral swabs while for Gram-negative bacteria the agreement of laboratory results was 55 % for nasal swabs and 87 % for oral swabs. In conclusion it has been shown that participants of the GNC are exposed to cats and dogs and that the sampling of cats and dogs by their owners is a feasible method which can be a useful tool for zoonoses research in population-based studies.

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.

A computer program for sample size computations for banding studies

USGS Publications Warehouse

Wilson, K.R.; Nichols, J.D.; Hines, J.E.

1989-01-01

Sample sizes necessary for estimating survival rates of banded birds, adults and young, are derived based on specified levels of precision. The banding study can be new or ongoing. The desired coefficient of variation (CV) for annual survival estimates, the CV for mean annual survival estimates, and the length of the study must be specified to compute sample sizes. A computer program is available for computation of the sample sizes, and a description of the input and output is provided.

Clinical application of microsampling versus conventional sampling techniques in the quantitative bioanalysis of antibiotics: a systematic review.

PubMed

Guerra Valero, Yarmarly C; Wallis, Steven C; Lipman, Jeffrey; Stove, Christophe; Roberts, Jason A; Parker, Suzanne L

2018-03-01

Conventional sampling techniques for clinical pharmacokinetic studies often require the removal of large blood volumes from patients. This can result in a physiological or emotional burden, particularly for neonates or pediatric patients. Antibiotic pharmacokinetic studies are typically performed on healthy adults or general ward patients. These may not account for alterations to a patient's pathophysiology and can lead to suboptimal treatment. Microsampling offers an important opportunity for clinical pharmacokinetic studies in vulnerable patient populations, where smaller sample volumes can be collected. This systematic review provides a description of currently available microsampling techniques and an overview of studies reporting the quantitation and validation of antibiotics using microsampling. A comparison of microsampling to conventional sampling in clinical studies is included.

A study of the temporal variability of atrazine in private well water. Part I: Study design, implementation, and database development

USGS Publications Warehouse

Lorber, M.; Johnson, Kevin; Kross, B.; Pinsky, P.; Burmeister, L.; Thurman, M.; Wilkins, A.; Hallberg, G.

1997-01-01

In 1988, the Iowa Department of Natural Resources, along with the University of Iowa conducted the Statewide Rural Well Water Survey, commonly known as SWRL. A total of 686 private rural drinking water wells was selected by use of a probability sample and tested for pesticides and nitrates. Sixty-eight of these wells, the '10% repeat' wells, were additionally sampled in October, 1990 and June, 1991. Starting in November, 1991, the University of Iowa, with sponsorship from the United States Environmental Protection Agency, revisited these wells to begin a study of the temporal variability of atrazine and nitrates in wells. Other wells, which had originally tested positive for atrazine in SWRL but were not in the 10% repeat population, were added to the study population. Temporal sampling for a year-long period began in February of 1992 and concluded in January of 1993. All wells were sampled monthly, one subset was sampled weekly, and a second subset was sampled for 14-day consecutive periods. Two unique aspects of this study were the use of an immunoassay technique to screen for triazines before gas chromatography/mass spectrometry (GC/MS) analysis and quantification of atrazine, and the use of well owners to sample the wells. A total of 1771 samples from 83 wells are in the final data base for this study. This paper reviews the study design, the analytical methodologies, and development of the data base. A companion paper discusses the analysis of the data from this survey.

What is the optimum sample size for the study of peatland testate amoeba assemblages?

PubMed

Mazei, Yuri A; Tsyganov, Andrey N; Esaulov, Anton S; Tychkov, Alexander Yu; Payne, Richard J

2017-10-01

Testate amoebae are widely used in ecological and palaeoecological studies of peatlands, particularly as indicators of surface wetness. To ensure data are robust and comparable it is important to consider methodological factors which may affect results. One significant question which has not been directly addressed in previous studies is how sample size (expressed here as number of Sphagnum stems) affects data quality. In three contrasting locations in a Russian peatland we extracted samples of differing size, analysed testate amoebae and calculated a number of widely-used indices: species richness, Simpson diversity, compositional dissimilarity from the largest sample and transfer function predictions of water table depth. We found that there was a trend for larger samples to contain more species across the range of commonly-used sample sizes in ecological studies. Smaller samples sometimes failed to produce counts of testate amoebae often considered minimally adequate. It seems likely that analyses based on samples of different sizes may not produce consistent data. Decisions about sample size need to reflect trade-offs between logistics, data quality, spatial resolution and the disturbance involved in sample extraction. For most common ecological applications we suggest that samples of more than eight Sphagnum stems are likely to be desirable. Copyright © 2017 Elsevier GmbH. All rights reserved.

Confocal Raman studies in determining crystalline nature of PECVD grown Si nanowires

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

Ahmed, Nafis; Bhargav, P. Balaji; Ramasamy, P.

2015-06-24

Silicon nanowires of diameter ∼200 nm and length of 2-4 µm are grown in the plasma enhanced chemical vapour deposition technique using nanoclustered Au catalyst assisted vapour-liquid-solid process. The crystallinity in the as-grown and annealed samples is studied using confocal Raman spectroscopic studies. Amorphous phase is formed in the as-grown samples. Structural studies using high resolution transmission electron microscopy confirm the polycrystalline nature in the annealed sample.

Sample environment for in situ synchrotron corrosion studies of materials in extreme environments

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

Elbakhshwan, Mohamed S.; Gill, Simerjeet K.; Motta, Arthur T.

A new in situ sample environment has been designed and developed to study the interfacial interactions of nuclear cladding alloys with high temperature steam. The sample environment is particularly optimized for synchrotron X-ray diffraction (XRD) studies for in situ structural analysis. The sample environment is highly corrosion resistant and can be readily adapted for steam environments. The in situ sample environment design complies with G2 ASTM standards for studying corrosion in zirconium and its alloys and offers remote temperature and pressure monitoring during the in situ data collection. The use of the in situ sample environment is exemplified by monitoringmore » the oxidation of metallic zirconium during exposure to steam at 350°C. Finally, the in situ sample environment provides a powerful tool for fundamental understanding of corrosion mechanisms by elucidating the substoichiometric oxide phases formed during early stages of corrosion, which can provide a better understanding the oxidation process.« less

Sample environment for in situ synchrotron corrosion studies of materials in extreme environments

DOE PAGES

Elbakhshwan, Mohamed S.; Gill, Simerjeet K.; Motta, Arthur T.; ...

2016-10-25

A new in situ sample environment has been designed and developed to study the interfacial interactions of nuclear cladding alloys with high temperature steam. The sample environment is particularly optimized for synchrotron X-ray diffraction (XRD) studies for in situ structural analysis. The sample environment is highly corrosion resistant and can be readily adapted for steam environments. The in situ sample environment design complies with G2 ASTM standards for studying corrosion in zirconium and its alloys and offers remote temperature and pressure monitoring during the in situ data collection. The use of the in situ sample environment is exemplified by monitoringmore » the oxidation of metallic zirconium during exposure to steam at 350°C. Finally, the in situ sample environment provides a powerful tool for fundamental understanding of corrosion mechanisms by elucidating the substoichiometric oxide phases formed during early stages of corrosion, which can provide a better understanding the oxidation process.« less

Patient acceptability and practical implications of pharmacokinetic studies in patients with advanced cancer.

PubMed

Dobbs, N A; Twelves, C J; Ramirez, A J; Towlson, K E; Gregory, W M; Richards, M A

1993-01-01

We have studied the practical implications and acceptability to patients of pharmacokinetic studies in 34 women receiving anthracyclines for advanced breast cancer. The following parameters were recorded: age, ECOG performance status, psychological state (Rotterdam Symptom Checklist), cytotoxic drug and dose, number of venepunctures for treatment and sampling, and time when the sampling cannula was removed. Immediately after finishing pharmacokinetic sampling, patients completed a questionnaire which revealed that (i) all patients understood sampling was for research, (ii) 35% of patients experienced problems with sampling, (iii) benefits from participation were perceived by 56% of patients. Of 20 patients later questioned after completion of their treatment course, 40% recalled difficulties with blood sampling. Factors identifying in advance those patients who tolerate pharmacokinetic studies poorly were not identified but the number of venepunctures should be minimised. Patients may also perceive benefits from 'non-therapeutic' research.

Horizons and opportunities in lunar sample science

NASA Technical Reports Server (NTRS)

1985-01-01

The Moon is the cornerstone of planetary science. Lunar sample studies were fundamental in developing an understanding of the early evolution and continued development of planetary bodies, and have led to major revisions in understanding of processes for the accumulation of planetesimals and the formation of planets. Studies of lunar samples have increased an understanding of impact cratering, meteoroid and micrometeoroid fluxes, the interaction of planetary surfaces with radiations and particles, and even the history of the Sun. The lunar sample research program was especially productive, but by no means have all the important answers been determined; continued study of lunar samples will further illuminate the shadows of our knowledge about the solar system. Further, the treasures returned through the Apollo program provide information that is required for a return to the Moon, beginning with new exploration (Lunar Geoscience Observer (LGO)), followed by intensive study (new sample return missions), and eventually culminating in a lunar base and lunar resource utilization.

Forensic Tools to Track and Connect Physical Samples to Related Data

NASA Astrophysics Data System (ADS)

Molineux, A.; Thompson, A. C.; Baumgardner, R. W.

2016-12-01

Identifiers, such as local sample numbers, are critical to successfully connecting physical samples and related data. However, identifiers must be globally unique. The International Geo Sample Number (IGSN) generated when registering the sample in the System for Earth Sample Registration (SESAR) provides a globally unique alphanumeric code associated with basic metadata, related samples and their current physical storage location. When registered samples are published, users can link the figured samples to the basic metadata held at SESAR. The use cases we discuss include plant specimens from a Permian core, Holocene corals and derived powders, and thin sections with SEM stubs. Much of this material is now published. The plant taxonomic study from the core is a digital pdf and samples can be directly linked from the captions to the SESAR record. The study of stable isotopes from the corals is not yet digitally available, but individual samples are accessible. Full data and media records for both studies are located in our database where higher quality images, field notes, and section diagrams may exist. Georeferences permit mapping in current and deep time plate configurations. Several aspects emerged during this study. The first, ensure adequate and consistent details are registered with SESAR. Second, educate and encourage the researcher to obtain IGSNs. Third, publish the archive numbers, assigned prior to publication, alongside the IGSN. This provides access to further data through an Integrated Publishing Toolkit (IPT)/aggregators/or online repository databases, thus placing the initial sample in a much richer context for future studies. Fourth, encourage software developers to customize community software to extract data from a database and use it to register samples in bulk. This would improve workflow and provide a path for registration of large legacy collections.

ZnO/Ag nanocomposite: an efficient catalyst for degradation studies of textile effluents under visible light.

PubMed

Saravanan, R; Karthikeyan, N; Gupta, V K; Thirumal, E; Thangadurai, P; Narayanan, V; Stephen, A

2013-05-01

Degradation of model organic dye and industry effluent was studied using different weight percentages of Ag into ZnO as a catalyst. In this study, the catalysts were prepared by thermal decomposition method, which was employed for the first time in the preparation of ZnO/Ag nanocomposite catalysts. The physical and chemical properties of the prepared samples were studied using various techniques. The specific surface area, which plays an important role in the photocatalytic degradation, was studied using BET analysis and 10 wt.% Ag into ZnO showed the best degrading efficiency. The optical absorption (UV-vis) and emission (PL) properties of the samples were studied and results suggest better photocatalytic properties for 10 wt.% Ag sample compared to other samples. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Health Status of Gulf War and Era Veterans Serving in the US Military in 2000.

PubMed

Porter, Ben; Long, Kyna; Rull, Rudolph P; Dursa, Erin K

2018-05-01

This research describes Gulf War and era veterans enrolled in the Millennium Cohort Study, who were sampled from US military personnel serving in 2000, and compares health characteristics of this sample to a Department of Veterans Affairs study sampled from the complete population. Demographics characteristics of this sample were described. Self-reported health characteristics were compared between the two studies. Gulf War and era veterans in the Millennium Cohort were generally healthier than in the VA study; they had fewer medical conditions and mental health disorders and better self-reported health. In both studies, Gulf War veterans had poorer health outcomes than era veterans. The Millennium Cohort Study is a unique resource for examining the long-term health effects of Gulf War deployment, particularly comparing deployed and nondeployed personnel and examining illnesses with long latencies.

Social Competence in Preschool Children: Replication of Results and Clarification of a Hierarchical Measurement Model

ERIC Educational Resources Information Center

Santos, Antonio J.; Peceguina, Ines; Daniel, Joao R.; Shin, Nana; Vaughn, Brian E.

2013-01-01

This study tested assumptions and conclusions reached in an earlier confirmatory factor analysis (CFA) study of the social competence (SC) construct for preschool children. Two samples (total N = 408; a new Portuguese sample and one from US samples that had participated in the original study) contributed data. Seven SC indicators were tested for…

76 FR 56141 - Notice of Intent To Request New Information Collection

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-12

... level surveys of similar scope and size. The sample for each selected community will be strategically... of 2 hours per sample community. Full Study: The maximum sample size for the full study is 2,812... questionnaires. The initial sample size for this phase of the research is 100 respondents (10 respondents per...

Comparison of the Multiple-sample means with composite sample results for fecal indicator bacteria by quantitative PCR and culture

EPA Science Inventory

ABSTRACT: Few studies have addressed the efficacy of composite sampling for measurement of indicator bacteria by QPCR. In this study, composite results were compared to single sample results for culture- and QPCR-based water quality monitoring. Composite results for both methods ...

Observations of radiation fog chemistry in the Eastern United States

NASA Astrophysics Data System (ADS)

Straub, D.; Hutchings, J.; Herckes, P.

2010-07-01

The chemical composition of radiation fog in the Mid-Atlantic region of the United States has been the focus of an ongoing field campaign based in Selinsgrove, PA. This field study was established to provide a long term record that can be used to identify the effects of meteorology and air mass source regions on fog composition and to shed light on the role that fog can play in the production of secondary inorganic and organic aerosol mass. In the United States, studies that focus on radiation fog have been relatively rare. For the most part, they have been limited geographically to the Central Valley of California, though individual studies have also been conducted in the Central United States and along the Texas-Louisiana Gulf Coast. Sample collection for the current study began during the fall of 2007. Through 2009, samples from 25 radiation fog events have been obtained. A Caltech Heated Rod Cloudwater Collector (CHRCC) having a Dp50 of approximately 8 microns was used to collect one fog sample per event. Samples were typically collected between 2:00 AM and 7:00 AM under conditions of light winds, clear skies, and recent rainfall. Sample volumes ranged from 2.9 ml to 150 ml. Following collection, samples were analyzed for pH and then one of the following: major inorganic ions, dissolved total organic carbon, N-nitrosodimethylamine (NDMA), metals, or organic speciation. Through 2009, sample pH varied between 4.28 and 6.86 and averaged 5.03 based on H+ concentration. Ammonium and sulfate were found to be the most abundant ionic species in the fog samples. Sufficient ammonium was detected in nearly every sample to fully neutralize nitrate and sulfate. The concentrations of sulfate, nitrate, and ammonium observed in this study were lower than values reported in the literature for most other cloud and fog studies conducted in the US. Due to significant ammonium input, pH in the current study was higher than most other studies. Concentrations of total organic carbon averaged 7.22 mgC/L, which is lower than other radiation fogs studies but similar to that for many cloud studies. NDMA concentrations in two analyzed samples were considered high, but not outside the range that could be expected through equilibrium with potential gas phase concentrations.

Evaluation of anti-microbial activity of spore powder of Ganoderma lucidum on clinical isolates of Prevotella intermedia: A pilot study.

PubMed

Nayak, Ranganath N; Dixitraj, P T; Nayak, Aarati; Bhat, Kishore

2015-09-01

This study aimed at evaluating the anti-microbial activity of spore powder of Ganoderma lucidum on Prevotella intermedia isolated from subgingival plaque from chronic periodontitis patients. Written informed consent was obtained from each subject enrolled in the study. The Institutional Ethics Committee granted the ethical clearance for the study. This study included 20 patients diagnosed with chronic periodontitis. Pooled subgingival plaque samples were collected using sterile curettes from the deepest sites of periodontal pockets. The collected samples were then transported in 1 mL of reduced transport fluid. The organisms were cultured and confirmed. These organisms were then used for minimum inhibitory concentration (MIC) procedure. Mean of the MIC value obtained was calculated. Thirteen out of the 20 clinical samples were tested that showed sensitivity at various concentrations. Five samples showed sensitivity at all concentrations. Twelve samples showed sensitivity at 8 mcg/ml. Eleven samples showed sensitivity at 4 mcg/ml, 8 samples showed sensitivity at 2 mcg/ml, and 5 samples showed sensitivity even at 1 mcg/ml. Mean MIC value of G. lucidum spore powder for P. intermedia obtained was 3.62 mcg/ml. G. lucidum with its multipotential bioactivity could be used as an anti-microbial, in conjunction with conventional therapy in periodontal disease.

Diversity of Leptospira spp. in Rats and Environment from Urban Areas of Sarawak, Malaysia

PubMed Central

Pui, Chai Fung; Apun, Kasing; Su'ut, Lela

2017-01-01

Various prevalence studies on Leptospira in animals and humans, as well as environmental samples, had been conducted worldwide, including Malaysia. However, limited studies have been documented on the presence of pathogenic, intermediate, and saprophytic Leptospira in selected animals and environments. This study was therefore conducted to detect Leptospira spp. in rats, soil, and water from urban areas of Sarawak using the polymerase chain reaction (PCR) method. A total of 107 rats, 292 soil samples, and 324 water samples were collected from April 2014 to February 2015. Pathogenic Leptospira was present in 5.6% (6/107) of rats, 11.6% (34/292) of soil samples, and 1.9% (6/324) of water samples. Intermediate Leptospira was present in 2.7% (8/292) of soil samples and 1.9% (6/324) of water samples. Saprophytic Leptospira was present in 10.3% (11/107) of rats, 1.4% (4/292) of soil samples, and 0.3% (1/324) of water samples. From this study, 76 Leptospira spp. were isolated. Based on DNA sequencing, the dominant Leptospira spp. circulating in urban areas of Sarawak are pathogenic Leptospira noguchii, intermediate Leptospira wolffii serovar Khorat, and saprophytic Leptospira meyeri, respectively. Overall, this study provided important surveillance data on the prevalence of Leptospira spp. from rats and the environment, with dominant local serovars in urban areas of Sarawak. PMID:28348601

Diversity of Leptospira spp. in Rats and Environment from Urban Areas of Sarawak, Malaysia.

PubMed

Pui, Chai Fung; Bilung, Lesley Maurice; Apun, Kasing; Su'ut, Lela

2017-01-01

Various prevalence studies on Leptospira in animals and humans, as well as environmental samples, had been conducted worldwide, including Malaysia. However, limited studies have been documented on the presence of pathogenic, intermediate, and saprophytic Leptospira in selected animals and environments. This study was therefore conducted to detect Leptospira spp. in rats, soil, and water from urban areas of Sarawak using the polymerase chain reaction (PCR) method. A total of 107 rats, 292 soil samples, and 324 water samples were collected from April 2014 to February 2015. Pathogenic Leptospira was present in 5.6% (6/107) of rats, 11.6% (34/292) of soil samples, and 1.9% (6/324) of water samples. Intermediate Leptospira was present in 2.7% (8/292) of soil samples and 1.9% (6/324) of water samples. Saprophytic Leptospira was present in 10.3% (11/107) of rats, 1.4% (4/292) of soil samples, and 0.3% (1/324) of water samples. From this study, 76 Leptospira spp. were isolated. Based on DNA sequencing, the dominant Leptospira spp. circulating in urban areas of Sarawak are pathogenic Leptospira noguchii , intermediate Leptospira wolffii serovar Khorat, and saprophytic Leptospira meyeri , respectively. Overall, this study provided important surveillance data on the prevalence of Leptospira spp. from rats and the environment, with dominant local serovars in urban areas of Sarawak.

Measuring eating disorder attitudes and behaviors: a reliability generalization study

PubMed Central

2014-01-01

Background Although score reliability is a sample-dependent characteristic, researchers often only report reliability estimates from previous studies as justification for employing particular questionnaires in their research. The present study followed reliability generalization procedures to determine the mean score reliability of the Eating Disorder Inventory and its most commonly employed subscales (Drive for Thinness, Bulimia, and Body Dissatisfaction) and the Eating Attitudes Test as a way to better identify those characteristics that might impact score reliability. Methods Published studies that used these measures were coded based on their reporting of reliability information and additional study characteristics that might influence score reliability. Results Score reliability estimates were included in 26.15% of studies using the EDI and 36.28% of studies using the EAT. Mean Cronbach’s alphas for the EDI (total score = .91; subscales = .75 to .89), EAT-40 (total score = .81) and EAT-26 (total score = .86; subscales = .56 to .80) suggested variability in estimated internal consistency. Whereas some EDI subscales exhibited higher score reliability in clinical eating disorder samples than in nonclinical samples, other subscales did not exhibit these differences. Score reliability information for the EAT was primarily reported for nonclinical samples, making it difficult to characterize the effect of type of sample on these measures. However, there was a tendency for mean score reliability to be higher in the adult (vs. adolescent) samples and in female (vs. male) samples. Conclusions Overall, this study highlights the importance of assessing and reporting internal consistency during every test administration because reliability is affected by characteristics of the participants being examined. PMID:24764530

Generalizability of causal inference in observational studies under retrospective convenience sampling.

PubMed

Hu, Zonghui; Qin, Jing

2018-05-20

Many observational studies adopt what we call retrospective convenience sampling (RCS). With the sample size in each arm prespecified, RCS randomly selects subjects from the treatment-inclined subpopulation into the treatment arm and those from the control-inclined into the control arm. Samples in each arm are representative of the respective subpopulation, but the proportion of the 2 subpopulations is usually not preserved in the sample data. We show in this work that, under RCS, existing causal effect estimators actually estimate the treatment effect over the sample population instead of the underlying study population. We investigate how to correct existing methods for consistent estimation of the treatment effect over the underlying population. Although RCS is adopted in medical studies for ethical and cost-effective purposes, it also has a big advantage for statistical inference: When the tendency to receive treatment is low in a study population, treatment effect estimators under RCS, with proper correction, are more efficient than their parallels under random sampling. These properties are investigated both theoretically and through numerical demonstration. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

[The research protocol III. Study population].

PubMed

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

2016-01-01

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

Targeted or whole genome sequencing of formalin fixed tissue samples: potential applications in cancer genomics.

PubMed

Munchel, Sarah; Hoang, Yen; Zhao, Yue; Cottrell, Joseph; Klotzle, Brandy; Godwin, Andrew K; Koestler, Devin; Beyerlein, Peter; Fan, Jian-Bing; Bibikova, Marina; Chien, Jeremy

2015-09-22

Current genomic studies are limited by the poor availability of fresh-frozen tissue samples. Although formalin-fixed diagnostic samples are in abundance, they are seldom used in current genomic studies because of the concern of formalin-fixation artifacts. Better characterization of these artifacts will allow the use of archived clinical specimens in translational and clinical research studies. To provide a systematic analysis of formalin-fixation artifacts on Illumina sequencing, we generated 26 DNA sequencing data sets from 13 pairs of matched formalin-fixed paraffin-embedded (FFPE) and fresh-frozen (FF) tissue samples. The results indicate high rate of concordant calls between matched FF/FFPE pairs at reference and variant positions in three commonly used sequencing approaches (whole genome, whole exome, and targeted exon sequencing). Global mismatch rates and C · G > T · A substitutions were comparable between matched FF/FFPE samples, and discordant rates were low (<0.26%) in all samples. Finally, low-pass whole genome sequencing produces similar pattern of copy number alterations between FF/FFPE pairs. The results from our studies suggest the potential use of diagnostic FFPE samples for cancer genomic studies to characterize and catalog variations in cancer genomes.

A Comparison Study of Sampling and Analyzing Volatile Organic Compounds in Air in Kuwait by Using Tedlar Bags/Canisters and GC-MS with a Cryogenic Trap

PubMed Central

Tang, Hongmao; Beg, Khaliq R.; Al-Otaiba, Yousef

2006-01-01

Kuwait experiences desert climatic weather. Due to the extreme hot and dry conditions in this country, some analytical phenomena have been discovered. Therefore, a systematic study of sampling and analyzing volatile organic compounds in air by using GC-MS with a cryogenic trap is reported in this paper. This study included comparisons of using different sample containers such as Tedlar bags and SUMMA canisters, and different cryogenic freezing-out air volumes in the trap. Calibration curves for different compounds and improvement of replicated analysis results were also reported here. The study found that using different sample containers produced different results. Analysis of ambient air samples collected in Tedlar bags obtained several volatile organic compounds with large concentrations compared to using SUMMA canisters. Therefore, to choose a sample container properly is a key element for successfully completing a project. Because GC-MS with a cryogenic trap often generates replicated results with poor agreement, an internal standard added to gas standards and air samples by using a gas syringe was tested. The study results proved that it helped to improve the replicated results. PMID:16699723

A comparison study of sampling and analyzing volatile organic compounds in air in Kuwait by using Tedlar bags/canisters and GC-MS with a cryogenic trap.

PubMed

Tang, Hongmao; Beg, Khaliq R; Al-Otaiba, Yousef

2006-05-12

Kuwait experiences desert climatic weather. Due to the extreme hot and dry conditions in this country, some analytical phenomena have been discovered. Therefore, a systematic study of sampling and analyzing volatile organic compounds in air by using GC-MS with a cryogenic trap is reported in this paper. This study included comparisons of using different sample containers such as Tedlar bags and SUMMA canisters, and different cryogenic freezing-out air volumes in the trap. Calibration curves for different compounds and improvement of replicated analysis results were also reported here. The study found that using different sample containers produced different results. Analysis of ambient air samples collected in Tedlar bags obtained several volatile organic compounds with large concentrations compared to using SUMMA canisters. Therefore, to choose a sample container properly is a key element for successfully completing a project. Because GC-MS with a cryogenic trap often generates replicated results with poor agreement, an internal standard added to gas standards and air samples by using a gas syringe was tested. The study results proved that it helped to improve the replicated results.

Application of allflex conservation buffer in illumina genotyping.

PubMed

de Groot, M; Ras, T; van Haeringen, W A

2016-12-01

This experiment was designed to study if liquid conservation buffer used in the novel Tissue Sampling Technology (TST) from Allflex can be used for Illumina BeadChip genotyping. Ear punches were collected from 6 bovine samples, using both the Tissue Sampling Unit (TSU) as well as the Total Tagger Universal (TTU) collection system. The stability of the liquid conservation buffer was tested by genotyping samples on Illumina BeadChips, incubated at 0, 3, 15, 24, 48, 72, 168, 336, 720 h after sample collection. Additionally, a replenishment study was designed to test how often the liquid conservation buffer could be completely replenished before a significant call rate drop could be observed. Results from the stability study showed an average call rate of 0.993 for samples collected with the TSU system and 0.953 for samples collected with the TTU system, both exceeding the inclusion threshold call rate of 0.85. As an additional control, the identity of the individual animals was confirmed using the International Society of Animal Genetics (ISAG) recommended SNP panel. The replenishment study revealed a slight drop in the sample call rate after replenishing the conservation buffer for the fourth time for the TSU as well as the TTU samples. In routine analysis, this application allows for multiple experiments to be performed on the liquid conservation buffer, while maintaining the tissue samples for future use. The data collected in this study shows that the liquid conservation buffer used in the TST system can be used for Illumina BeadChip genotyping applications.

[Effect sizes, statistical power and sample sizes in "the Japanese Journal of Psychology"].

PubMed

Suzukawa, Yumi; Toyoda, Hideki

2012-04-01

This study analyzed the statistical power of research studies published in the "Japanese Journal of Psychology" in 2008 and 2009. Sample effect sizes and sample statistical powers were calculated for each statistical test and analyzed with respect to the analytical methods and the fields of the studies. The results show that in the fields like perception, cognition or learning, the effect sizes were relatively large, although the sample sizes were small. At the same time, because of the small sample sizes, some meaningful effects could not be detected. In the other fields, because of the large sample sizes, meaningless effects could be detected. This implies that researchers who could not get large enough effect sizes would use larger samples to obtain significant results.

Evaluation of two types of swabs for sampling allograft musculoskeletal tissue.

PubMed

Varettas, Kerry

2015-01-01

Allograft musculoskeletal tissue is commonly sampled by a swab for bioburden screening. To determine if bioburden recovery could be improved at the pre-analytical stage, two swab systems were evaluated: the Amies gel swab and the ESwab. In vitro studies were performed to determine the recovery of each swab system with <100 colony-forming unit of challenge organisms using inoculated swabs and by sampling inoculated femoral heads. The standard culture protocol used in this laboratory was also evaluated after sampling of inoculated femoral heads. A prospective study was performed with both swab systems used in parallel to sample cadaveric allograft musculoskeletal tissue. The challenge organisms could be recovered from the in vitro inoculated studies. The standard culture protocol in this laboratory recovered all challenge organisms from both swab systems. One hundred and six paired Amies and ESwabs were collected from eight cadaveric donors with skin commensals the predominant isolates. The sampling of an inoculated femoral head was included to reflect routine swab sampling practice as was the inclusion of the standard method used in this laboratory. This appears to be the first study to compare Amies gel swabs with ESwabs to sample allograft femoral heads and in a prospective study with cadaveric allograft musculoskeletal tissue. Other comparative studies of swab systems have used a much higher inoculum to mimic an infection; however, sepsis is an exclusion criterion for allograft donors. It was found that the Amies gel swab and ESwab are both suitable sampling devices for bioburden testing of allograft musculoskeletal tissue. © 2014 Royal Australasian College of Surgeons.

Pesticides in Wyoming Groundwater, 2008-10

USGS Publications Warehouse

Eddy-Miller, Cheryl A.; Bartos, Timothy T.; Taylor, Michelle L.

2013-01-01

Groundwater samples were collected from 296 wells during 1995-2006 as part of a baseline study of pesticides in Wyoming groundwater. In 2009, a previous report summarized the results of the baseline sampling and the statistical evaluation of the occurrence of pesticides in relation to selected natural and anthropogenic (human-related) characteristics. During 2008-10, the U.S. Geological Survey, in cooperation with the Wyoming Department of Agriculture, resampled a subset (52) of the 296 wells sampled during 1995-2006 baseline study in order to compare detected compounds and respective concentrations between the two sampling periods and to evaluate the detections of new compounds. The 52 wells were distributed similarly to sites used in the 1995-2006 baseline study with respect to geographic area and land use within the geographic area of interest. Because of the use of different types of reporting levels and variability in reporting-level values during both the 1995-2006 baseline study and the 2008-10 resampling study, analytical results received from the laboratory were recensored. Two levels of recensoring were used to compare pesticides—a compound-specific assessment level (CSAL) that differed by compound and a common assessment level (CAL) of 0.07 microgram per liter. The recensoring techniques and values used for both studies, with the exception of the pesticide 2,4-D methyl ester, were the same. Twenty-eight different pesticides were detected in samples from the 52 wells during the 2008-10 resampling study. Pesticide concentrations were compared with several U.S. Environmental Protection Agency drinking-water standards or health advisories for finished (treated) water established under the Safe Drinking Water Act. All detected pesticides were measured at concentrations smaller than U.S. Environmental Protection Agency drinking-water standards or health advisories where applicable (many pesticides did not have standards or advisories). One or more pesticides were detected at concentrations greater than the CAL in water from 16 of 52 wells sampled (about 31 percent) during the resampling study. Detected pesticides were classified into one of six types: herbicides, herbicide degradates, insecticides, insecticide degradates, fungicides, or fungicide degradates. At least 95 percent of detected pesticides were classified as herbicides or herbicide degradates. The number of different pesticides detected in samples from the 52 wells was similar between the 1995-2006 baseline study (30 different pesticides) and 2008-2010 resampling study (28 different pesticides). Thirteen pesticides were detected during both studies. The change in the number of pesticides detected (without regard to which pesticide was detected) in groundwater samples from each of the 52 wells was evaluated and the number of pesticides detected in groundwater did not change for most of the wells (32). Of those that did have a difference between the two studies, 17 wells had more pesticide detections in groundwater during the 1995-2006 baseline study, whereas only 3 wells had more detections during the 2008-2010 resampling study. The difference in pesticide concentrations in groundwater samples from each of the 52 wells was determined. Few changes in concentration between the 1995-2006 baseline study and the 2008-2010 resampling study were seen for most detected pesticides. Seven pesticides had a greater concentration detected in the groundwater from the same well during the baseline sampling compared to the resampling study. Concentrations of prometon, which was detected in 17 wells, were greater in the baseline study sample compared to the resampling study sample from the same well 100 percent of the time. The change in the number of pesticides detected (without regard to which pesticide was detected) in groundwater samples from each of the 52 wells with respect to land use and geographic area was calculated. All wells with land use classified as agricultural had the same or a smaller number of pesticides detected in the resampling study compared to the baseline study. All wells in the Bighorn Basin geographic area also had the same or a smaller number of pesticides detected in the resampling study compared to the baseline study.

One mouse, one pharmacokinetic profile: quantitative whole blood serial sampling for biotherapeutics.

PubMed

Joyce, Alison P; Wang, Mengmeng; Lawrence-Henderson, Rosemary; Filliettaz, Cynthia; Leung, Sheldon S; Xu, Xin; O'Hara, Denise M

2014-07-01

The purpose of this study was to validate the approach of serial sampling from one mouse through ligand binding assay (LBA) quantification of dosed biotherapeutic in diluted whole blood to derive a pharmacokinetic (PK) profile. This investigation compared PK parameters obtained using serial and composite sampling methods following administration of human IgG monoclonal antibody. The serial sampling technique was established by collecting 10 μL of blood via tail vein at each time point following drug administration. Blood was immediately diluted into buffer followed by analyte quantitation using Gyrolab to derive plasma concentrations. Additional studies were conducted to understand matrix and sampling site effects on drug concentrations. The drug concentration profiles, irrespective of biological matrix, and PK parameters using both sampling methods were not significantly different. There were no sampling site effects on drug concentration measurements except that concentrations were slightly lower in sodium citrated plasma than other matrices. We recommend the application of mouse serial sampling, particularly with limiting drug supply or specialized animal models. Overall the efficiencies gained by serial sampling were 40-80% savings in study cost, animal usage, study length and drug conservation while inter-subject variability across PK parameters was less than 30%.

Mars Sample Return Orbiter Architecture Options — Results of the ESA Mars Sample Return Architecture Assessment Study

NASA Astrophysics Data System (ADS)

Derz, U.; Joffre, E.; Perkinson, M.-C.; Huesing, J.; Beyer, F.; Sanchez Perez, J. M.

2018-04-01

This paper presents the identified most promising chemical and electric propulsion architecture options of the Mars Sample Return (MSR) orbiter identified during the recent ESA MSR Architecture Assessment Study.

The chemical and catalytic properties of nanocrystalline metal oxides prepared through modified sol-gel synthesis

NASA Astrophysics Data System (ADS)

Carnes, Corrie Leigh

The goal of this research was to synthesize, characterize and study the chemical properties of nanocrystalline metal oxides. Nanocrystalline (NC) ZnO, CuO, NiO, Al2O3, and the binary Al2O 3/MgO and ZnO/CuO were prepared through modified sol gel methods. These NC metal oxides were studied in comparison to the commercial (CM) metal oxides. The samples were characterized by XRD, TGA, FTIR, BET, and TEM. The NC samples were all accompanied by a significant increase in surface area and decrease in crystallite size. Several chemical reactions were studied to compare the NC samples to the CM samples. One of the reactions involved a high temperature reaction between carbon tetrachloride and the oxide to form carbon dioxide and the corresponding metal chloride. A similar high temperature reaction was conducted between the metal oxide and hydrogen sulfide to form water and the corresponding metal sulfide. A room temperature gas phase adsorption was studied where SO2 was adsorbed onto the oxide. A liquid phase adsorption conducted at room temperature was the destructive adsorption of paraoxon (a toxic insecticide). In all reactions the NC samples exhibited greater activity, destroying or adsorbing a larger amount of the toxins compared to the CM samples. To better study surface area effects catalytic reactions were also studied. The catalysis of methanol was studied over the nanocrystalline ZnO, CuO, NiO, and ZnO/CuO samples in comparison to their commercial counterparts. In most cases the NC samples proved to be more active catalysts, having higher percent conversions and turnover numbers. A second catalytic reaction was also studied, this reaction was investigated to look at the support effects. The catalysis of cyclopropane to propane was studied over Pt and Co catalysts. These catalysts were supported onto NC and CM alumina by impregnation. By observing differences in the catalytic behavior, support effects have become apparent.

Using dried blood spot sampling to improve data quality and reduce animal use in mouse pharmacokinetic studies.

PubMed

Wickremsinhe, Enaksha R; Perkins, Everett J

2015-03-01

Traditional pharmacokinetic analysis in nonclinical studies is based on the concentration of a test compound in plasma and requires approximately 100 to 200 μL blood collected per time point. However, the total blood volume of mice limits the number of samples that can be collected from an individual animal-often to a single collection per mouse-thus necessitating dosing multiple mice to generate a pharmacokinetic profile in a sparse-sampling design. Compared with traditional methods, dried blood spot (DBS) analysis requires smaller volumes of blood (15 to 20 μL), thus supporting serial blood sampling and the generation of a complete pharmacokinetic profile from a single mouse. Here we compare plasma-derived data with DBS-derived data, explain how to adopt DBS sampling to support discovery mouse studies, and describe how to generate pharmacokinetic and pharmacodynamic data from a single mouse. Executing novel study designs that use DBS enhances the ability to identify and streamline better drug candidates during drug discovery. Implementing DBS sampling can reduce the number of mice needed in a drug discovery program. In addition, the simplicity of DBS sampling and the smaller numbers of mice needed translate to decreased study costs. Overall, DBS sampling is consistent with 3Rs principles by achieving reductions in the number of animals used, decreased restraint-associated stress, improved data quality, direct comparison of interanimal variability, and the generation of multiple endpoints from a single study.

Using Dried Blood Spot Sampling to Improve Data Quality and Reduce Animal Use in Mouse Pharmacokinetic Studies

PubMed Central

Wickremsinhe, Enaksha R; Perkins, Everett J

2015-01-01

Traditional pharmacokinetic analysis in nonclinical studies is based on the concentration of a test compound in plasma and requires approximately 100 to 200 µL blood collected per time point. However, the total blood volume of mice limits the number of samples that can be collected from an individual animal—often to a single collection per mouse—thus necessitating dosing multiple mice to generate a pharmacokinetic profile in a sparse-sampling design. Compared with traditional methods, dried blood spot (DBS) analysis requires smaller volumes of blood (15 to 20 µL), thus supporting serial blood sampling and the generation of a complete pharmacokinetic profile from a single mouse. Here we compare plasma-derived data with DBS-derived data, explain how to adopt DBS sampling to support discovery mouse studies, and describe how to generate pharmacokinetic and pharmacodynamic data from a single mouse. Executing novel study designs that use DBS enhances the ability to identify and streamline better drug candidates during drug discovery. Implementing DBS sampling can reduce the number of mice needed in a drug discovery program. In addition, the simplicity of DBS sampling and the smaller numbers of mice needed translate to decreased study costs. Overall, DBS sampling is consistent with 3Rs principles by achieving reductions in the number of animals used, decreased restraint-associated stress, improved data quality, direct comparison of interanimal variability, and the generation of multiple endpoints from a single study. PMID:25836959

Mars Sample Return Architecture Assessment Study

NASA Astrophysics Data System (ADS)

Centuori, S.; Hermosín, P.; Martín, J.; De Zaiacomo, G.; Colin, S.; Godfrey, A.; Myles, J.; Johnson, H.; Sachdev, T.; Ahmed, R.

2018-04-01

Current paper presents the results of ESA funded activity "Mars Sample Return Architecture Assessment Study" carried-out by DEIMOS Space, Lockheed Martin UK Ampthill, and MDA Corporation, where more than 500 mission design options have been studied.

14C sample preparation for AMS microdosing studies at Lund University using online combustion and septa-sealed vials

NASA Astrophysics Data System (ADS)

Sydoff, Marie; Stenström, Kristina

2010-04-01

The Department of Physics at Lund University is participating in a European Union project called EUMAPP (European Union Microdose AMS Partnership Programme), in which sample preparation and accelerator mass spectrometry (AMS) measurements of biological samples from microdosing studies have been made. This paper describes a simplified method of converting biological samples to solid graphite for 14C analysis with AMS. The method is based on online combustion of the samples, and reduction of CO 2 in septa-sealed vials. The septa-sealed vials and disposable materials are used to eliminate sample cross-contamination. Measurements of ANU and Ox I standards show deviations of 2% and 3%, respectively, relative to reference values. This level of accuracy is sufficient for biological samples from microdosing studies. Since the method has very few handling steps from sample to graphite, the risk of failure during the sample preparation process is minimized, making the method easy to use in routine preparation of samples.

Investigation of a Hybrid Wafer Scale Integration Technique that Mounts Discrete Integrated Circuit Die in a Silicon Substrate.

DTIC Science & Technology

1988-03-01

Polyimides as Planarizing and Insulative Coatings 2-21 III. Experimental Procedure, Equipment, and Materials 3-1 Wet Orientation Dependent Etching Study 3...1 Die Bond Adhesives Study .3-7 Fabrication of Samples for Electrical Testing 3-21 Evaluation of the Final Samples 3-45 IV. Experimental Results and...Discussion .. 4-1 We :ientation Dependent Etching Study Results 4-1 Die Attach Adhesives Study Results 4-21 Fabrication of Samples for Electrical

40 CFR 761.326 - Conducting the comparison study.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Conducting the comparison study. 761...-liquid PCB Remediation Waste Samples § 761.326 Conducting the comparison study. Extract or analyze the comparison study samples using the alternative method. For an alternative extraction method or alternative...

40 CFR 761.326 - Conducting the comparison study.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Conducting the comparison study. 761...-liquid PCB Remediation Waste Samples § 761.326 Conducting the comparison study. Extract or analyze the comparison study samples using the alternative method. For an alternative extraction method or alternative...

CIDR

Science.gov Websites

studies. Investigators must supply positive and negative controls. Current pricing for CIDR Program studies are for a minimum study size of 90 samples and increasing in multiples of 90. Please inquire for for the assay is included for CIDR Program studies. FFPE samples are supported for MethylationEPIC

Sample size for post-marketing safety studies based on historical controls.

PubMed

Wu, Yu-te; Makuch, Robert W

2010-08-01

As part of a drug's entire life cycle, post-marketing studies are an important part in the identification of rare, serious adverse events. Recently, the US Food and Drug Administration (FDA) has begun to implement new post-marketing safety mandates as a consequence of increased emphasis on safety. The purpose of this research is to provide exact sample size formula for the proposed hybrid design, based on a two-group cohort study with incorporation of historical external data. Exact sample size formula based on the Poisson distribution is developed, because the detection of rare events is our outcome of interest. Performance of exact method is compared to its approximate large-sample theory counterpart. The proposed hybrid design requires a smaller sample size compared to the standard, two-group prospective study design. In addition, the exact method reduces the number of subjects required in the treatment group by up to 30% compared to the approximate method for the study scenarios examined. The proposed hybrid design satisfies the advantages and rationale of the two-group design with smaller sample sizes generally required. 2010 John Wiley & Sons, Ltd.

Biomarker discovery study design for type 1 diabetes in The Environmental Determinants of Diabetes in the Young (TEDDY) study.

PubMed

Lee, Hye-Seung; Burkhardt, Brant R; McLeod, Wendy; Smith, Susan; Eberhard, Chris; Lynch, Kristian; Hadley, David; Rewers, Marian; Simell, Olli; She, Jin-Xiong; Hagopian, Bill; Lernmark, Ake; Akolkar, Beena; Ziegler, Anette G; Krischer, Jeffrey P

2014-07-01

The Environmental Determinants of Diabetes in the Young planned biomarker discovery studies on longitudinal samples for persistent confirmed islet cell autoantibodies and type 1 diabetes using dietary biomarkers, metabolomics, microbiome/viral metagenomics and gene expression. This article describes the details of planning The Environmental Determinants of Diabetes in the Young biomarker discovery studies using a nested case-control design that was chosen as an alternative to the full cohort analysis. In the frame of a nested case-control design, it guides the choice of matching factors, selection of controls, preparation of external quality control samples and reduction of batch effects along with proper sample allocation. Our design is to reduce potential bias and retain study power while reducing the costs by limiting the numbers of samples requiring laboratory analyses. It also covers two primary end points (the occurrence of diabetes-related autoantibodies and the diagnosis of type 1 diabetes). The resulting list of case-control matched samples for each laboratory was augmented with external quality control samples. Copyright © 2013 John Wiley & Sons, Ltd.

β-trace protein as a diagnostic marker for perilymphatic fluid fistula: a prospective controlled pilot study to test a sample collection technique.

PubMed

Bachmann-Harildstad, Gregor; Stenklev, Niels Christian; Myrvoll, Elin; Jablonski, Greg; Klingenberg, Olav

2011-01-01

The diagnosis of perilymphatic fluid (PLF) fistula is still challenging. Perilymphatic fluid fistula is one possible complication after stapedotomy or cochlear implant surgery. We have performed a prospective diagnostic pilot study to further investigate β-trace protein (β-TP) as a marker for PLF fistula. In this pilot study, we tested the sensitivity of the β-TP marker using a simple method for sample collection from the tympanic cavity. Prospective controlled diagnostic study. Two-center tertiary referral hospitals. A total of 35 adult patients undergoing ear surgery were included. Subjects were divided into 2 groups: 1) 19 patients undergoing stapedotomy were investigated for PLF fistula in samples obtained from the tympanic cavity and 2) 16 patients undergoing myringoplasty were investigated for PLF fistula in samples from the tympanic cavity. This group served as the control. Mean age +/- SD at surgery was 49.9 +/- 8.0 years in the study group and 39.69 +/- 15.47 years in the control group. β-Trace protein (prostaglandin D synthase) in tympanic cavity samples and serum samples was analyzed. The samples were collected by gradually filling the tympanic cavity with 100 to 200 μl sodium chloride and by immediately collecting a volume of 60 to 100 μl in a mucus specimen set container. The concentration of β-TP was quantified using laser nephelometry. The median β-TP in the study group was 0.8 mg/L (range, 0.05-4.5 mg/L). In the control group, the median β-TP value was 0.16 mg/L (range, 0.01-0.36 mg/L). Thirty-five percent of the values in the study group were below the highest value in the negative control group. The β-TP values of the tympanic cavity samples were significantly higher in the study group than in controls (p = 0.0001). The serum values were 0.55 +/- 0.18 and 0.53 +/- 0.11 mg/L, respectively. It may be feasible to test for PLF fistula using β-TP in samples from the tympanic cavity. Our results, however, suggest a relative low diagnostic sensitivity, given a cutoff that is set to obtain a high specificity when using a simple sample collection method. Furthermore, the test does not permit the distinction between PLF fistula and cerebrospinal fluid fistula. Further studies should focus on minimal dilution at sampling and on minimizing sample volumes.

Sample size determination for mediation analysis of longitudinal data.

PubMed

Pan, Haitao; Liu, Suyu; Miao, Danmin; Yuan, Ying

2018-03-27

Sample size planning for longitudinal data is crucial when designing mediation studies because sufficient statistical power is not only required in grant applications and peer-reviewed publications, but is essential to reliable research results. However, sample size determination is not straightforward for mediation analysis of longitudinal design. To facilitate planning the sample size for longitudinal mediation studies with a multilevel mediation model, this article provides the sample size required to achieve 80% power by simulations under various sizes of the mediation effect, within-subject correlations and numbers of repeated measures. The sample size calculation is based on three commonly used mediation tests: Sobel's method, distribution of product method and the bootstrap method. Among the three methods of testing the mediation effects, Sobel's method required the largest sample size to achieve 80% power. Bootstrapping and the distribution of the product method performed similarly and were more powerful than Sobel's method, as reflected by the relatively smaller sample sizes. For all three methods, the sample size required to achieve 80% power depended on the value of the ICC (i.e., within-subject correlation). A larger value of ICC typically required a larger sample size to achieve 80% power. Simulation results also illustrated the advantage of the longitudinal study design. The sample size tables for most encountered scenarios in practice have also been published for convenient use. Extensive simulations study showed that the distribution of the product method and bootstrapping method have superior performance to the Sobel's method, but the product method was recommended to use in practice in terms of less computation time load compared to the bootstrapping method. A R package has been developed for the product method of sample size determination in mediation longitudinal study design.

OSL technique for studies of jasper samples

NASA Astrophysics Data System (ADS)

Teixeira, Maria Inês; Caldas, Linda V. E.

2014-02-01

Jasper samples (green, red, brown, ocean and striped) were studied in relation to their optically stimulated luminescence (OSL) dosimetric properties, in this work. Since 2000, the radiation metrology group of IPEN has studied different stones as new materials for application in high-dose dosimetry. The jasper samples were exposed to different radiation doses, using the Gamma-cell 220 system (60Co) of IPEN. Calibration curves were obtained for the jasper samples between 50 Gy and 300 kGy. The reproducibility of the OSL response and the lower detection doses were determined. All five types of jasper samples showed their usefulness as irradiation indicators and as high-dose dosimeters, using the OSL technique.

Fish biodiversity sampling in stream ecosystems: a process for evaluating the appropriate types and amount of gear

USGS Publications Warehouse

Smith, Joseph M.; Wells, Sarah P.; Mather, Martha E.; Muth, Robert M.

2014-01-01

When researchers and managers initiate sampling on a new stream or river system, they do not know how effective each gear type is and whether their sampling effort is adequate. Although the types and amount of gear may be different for other studies, systems, and research questions, the five-step process described here for making sampling decisions and evaluating sampling efficiency can be applied widely to any system to restore, manage, and conserve aquatic ecosystems. It is believed that incorporating this gear-evaluation process into a wide variety of studies and ecosystems will increase rigour within and across aquatic biodiversity studies.

[Formal sample size calculation and its limited validity in animal studies of medical basic research].

PubMed

Mayer, B; Muche, R

2013-01-01

Animal studies are highly relevant for basic medical research, although their usage is discussed controversially in public. Thus, an optimal sample size for these projects should be aimed at from a biometrical point of view. Statistical sample size calculation is usually the appropriate methodology in planning medical research projects. However, required information is often not valid or only available during the course of an animal experiment. This article critically discusses the validity of formal sample size calculation for animal studies. Within the discussion, some requirements are formulated to fundamentally regulate the process of sample size determination for animal experiments.

Mars Rover Sample Return mission

NASA Technical Reports Server (NTRS)

Bourke, Roger D.; Kwok, Johnny H.; Friedlander, Alan

1989-01-01

To gain a detailed understanding of the character of the planet Mars, it is necessary to send vehicle to the surface and return selected samples for intensive study in earth laboratories. Toward that end, studies have been underway for several years to determine the technically feasible means for exploring the surface and returning selected samples. This paper describes several MRSR mission concepts that have emerged from the most recent studies.

Effects of High School Students' Perceptions of School Life Quality on Their Academic Motivation Levels

ERIC Educational Resources Information Center

Akin Kösterelioglu, Meltem; Kösterelioglu, Ilker

2015-01-01

This study aims to identify the effects of high school students' perceptions of school life quality on their academic motivation levels. The study was conducted on a sample of high school students (n = 2371) in Amasya Province in the fall semester of 2013-2014 academic year. Study sample was selected with the help of cluster sampling method. Data…

Quality of Life and Emotional Intelligence in a Sample of Kuwait University Students

ERIC Educational Resources Information Center

Al-Huwailah, Amthal

2017-01-01

The purpose of the study is to describe of the nature of the relationship between quality of Life and Emotional Intelligence in a sample of Kuwait University students, as well as to identify the differences between males and females in the variables of the study, The study sample consists of 400 students from the University of Kuwait, (200) males…

A Monte Carlo Study of Levene's Test of Homogeneity of Variance: Empirical Frequencies of Type I Error in Normal Distributions.

ERIC Educational Resources Information Center

Neel, John H.; Stallings, William M.

An influential statistics test recommends a Levene text for homogeneity of variance. A recent note suggests that Levene's test is upwardly biased for small samples. Another report shows inflated Alpha estimates and low power. Neither study utilized more than two sample sizes. This Monte Carlo study involved sampling from a normal population for…

Study samples are too small to produce sufficiently precise reliability coefficients.

PubMed

Charter, Richard A

2003-04-01

In a survey of journal articles, test manuals, and test critique books, the author found that a mean sample size (N) of 260 participants had been used for reliability studies on 742 tests. The distribution was skewed because the median sample size for the total sample was only 90. The median sample sizes for the internal consistency, retest, and interjudge reliabilities were 182, 64, and 36, respectively. The author presented sample size statistics for the various internal consistency methods and types of tests. In general, the author found that the sample sizes that were used in the internal consistency studies were too small to produce sufficiently precise reliability coefficients, which in turn could cause imprecise estimates of examinee true-score confidence intervals. The results also suggest that larger sample sizes have been used in the last decade compared with those that were used in earlier decades.

Application of work sampling technique to analyze logging operations.

Treesearch

Edwin S. Miyata; Helmuth M. Steinhilb; Sharon A. Winsauer

1981-01-01

Discusses the advantages and disadvantages of various time study methods for determining efficiency and productivity in logging. The work sampling method is compared with the continuous time-study method. Gives the feasibility, capability, and limitation of the work sampling method.

Examination of participant flow in the CONSORT diagram can improve the understanding of the generalizability of study results.

PubMed

Andrade, Chittaranjan

2015-11-01

A fundamental principle in research is that the findings of a study can only be generalized to the population from which the sample of the study was drawn. What this population was can be discerned from an examination of the study selection criteria. Additional insights can sometimes be gleaned from the study flowchart or CONSORT diagram, which may show sample attenuation between subject screening and final recruitment. Such sample attenuation, if present, implies further limitation to the generalizability of the study outcomes. Two large, 2-year, randomized controlled maintenance therapy trials are described to illustrate sample attenuation that limits study generalizability, one in the context of mindfulness-based cognitive therapy versus antidepressant drugs for recurrent major depressive disorder and the other in the context of quetiapine versus placebo for bipolar disorder. Readers therefore need to examine both study selection criteria and the CONSORT diagram in order to better understand the extent to which study results apply to the patients whom they see. © Copyright 2015 Physicians Postgraduate Press, Inc.

Sampling estimators of total mill receipts for use in timber product output studies

Treesearch

John P. Brown; Richard G. Oderwald

2012-01-01

Data from the 2001 timber product output study for Georgia was explored to determine new methods for stratifying mills and finding suitable sampling estimators. Estimators for roundwood receipts totals comprised several types: simple random sample, ratio, stratified sample, and combined ratio. Two stratification methods were examined: the Dalenius-Hodges (DH) square...

Photon interaction studies using 241Am g-rays

NASA Astrophysics Data System (ADS)

Ramachandran, N.; Karunakaran Nair, K.; Abdullah, K. K.; Varier, K. M.

2006-09-01

We have carried out some photon interaction measurements using 59.54 keV γ-rays from a ^{241}Am source. These include γ attenuation studies as well as photoelectric absorption studies in various samples. The attenuation studies have been made using leaf and wood samples, samples like sand, sugar etc., which contain particles of varying sizes as well as pellets and aqueous solutions of rare earth compounds. In the case of the leaf and wood samples, we have used the γ-ray attenuation technique for the determination of the water content in fresh and dried samples. The variation of the attenuation coefficient with particle size has been investigated for sand and sugar samples. The attenuation studies as well as the photoelectric studies in the case of rare earth elements have been carried out on samples containing such elements whose K-absorption edge energies lie below and close to the γ-energy used. Suitable compounds of the rare earth elements have been chosen as mixture absorbers in these investigations. A narrow beam good geometry set-up was used for the attenuation measurements. A well-shielded scattering geometry was used for the photoelectric measurements. The mixture rule was invoked to extract the values of the mass attenuation coefficients for the elements from those of the corresponding compounds. The results are consistent with theoretical values derived from the XCOM package.

Assessment of sampling stability in ecological applications of discriminant analysis

USGS Publications Warehouse

Williams, B.K.; Titus, K.

1988-01-01

A simulation study was undertaken to assess the sampling stability of the variable loadings in linear discriminant function analysis. A factorial design was used for the factors of multivariate dimensionality, dispersion structure, configuration of group means, and sample size. A total of 32,400 discriminant analyses were conducted, based on data from simulated populations with appropriate underlying statistical distributions. A review of 60 published studies and 142 individual analyses indicated that sample sizes in ecological studies often have met that requirement. However, individual group sample sizes frequently were very unequal, and checks of assumptions usually were not reported. The authors recommend that ecologists obtain group sample sizes that are at least three times as large as the number of variables measured.

Options in Extraterrestrial Sample Handling and Study

NASA Technical Reports Server (NTRS)

Papanastassiou, Dimitri A.

2000-01-01

This presentation mentions important service functions such as: sample preservation, hazard assessment, and handling. It also discuss how preliminary examination of samples is necessary for sample hazard assessment and for sample allocations. Clean facilities and clean sample handling are required. Conflicts, cross contamination issues will be present and need to be resolved. Extensive experience is available for extraterrestrial samples and must be sought and applied. Extensive experience is available in studies of pathogenicity and must be sought and applied as necessary. Advisory and oversight structures must also be in place

Statistical considerations for agroforestry studies

Treesearch

James A. Baldwin

1993-01-01

Statistical topics that related to agroforestry studies are discussed. These included study objectives, populations of interest, sampling schemes, sample sizes, estimation vs. hypothesis testing, and P-values. In addition, a relatively new and very much improved histogram display is described.

Automated DBS microsampling, microscale automation and microflow LC-MS for therapeutic protein PK.

PubMed

Zhang, Qian; Tomazela, Daniela; Vasicek, Lisa A; Spellman, Daniel S; Beaumont, Maribel; Shyong, BaoJen; Kenny, Jacqueline; Fauty, Scott; Fillgrove, Kerry; Harrelson, Jane; Bateman, Kevin P

2016-04-01

Reduce animal usage for discovery-stage PK studies for biologics programs using microsampling-based approaches and microscale LC-MS. We report the development of an automated DBS-based serial microsampling approach for studying the PK of therapeutic proteins in mice. Automated sample preparation and microflow LC-MS were used to enable assay miniaturization and improve overall assay throughput. Serial sampling of mice was possible over the full 21-day study period with the first six time points over 24 h being collected using automated DBS sample collection. Overall, this approach demonstrated comparable data to a previous study using single mice per time point liquid samples while reducing animal and compound requirements by 14-fold. Reduction in animals and drug material is enabled by the use of automated serial DBS microsampling for mice studies in discovery-stage studies of protein therapeutics.

Accounting for between-study variation in incremental net benefit in value of information methodology.

PubMed

Willan, Andrew R; Eckermann, Simon

2012-10-01

Previous applications of value of information methods for determining optimal sample size in randomized clinical trials have assumed no between-study variation in mean incremental net benefit. By adopting a hierarchical model, we provide a solution for determining optimal sample size with this assumption relaxed. The solution is illustrated with two examples from the literature. Expected net gain increases with increasing between-study variation, reflecting the increased uncertainty in incremental net benefit and reduced extent to which data are borrowed from previous evidence. Hence, a trial can become optimal where current evidence is sufficient assuming no between-study variation. However, despite the expected net gain increasing, the optimal sample size in the illustrated examples is relatively insensitive to the amount of between-study variation. Further percentage losses in expected net gain were small even when choosing sample sizes that reflected widely different between-study variation. Copyright © 2011 John Wiley & Sons, Ltd.

Composite Sampling Approaches for Bacillus anthracis Surrogate Extracted from Soil

PubMed Central

France, Brian; Bell, William; Chang, Emily; Scholten, Trudy

2015-01-01

Any release of anthrax spores in the U.S. would require action to decontaminate the site and restore its use and operations as rapidly as possible. The remediation activity would require environmental sampling, both initially to determine the extent of contamination (hazard mapping) and post-decon to determine that the site is free of contamination (clearance sampling). Whether the spore contamination is within a building or outdoors, collecting and analyzing what could be thousands of samples can become the factor that limits the pace of restoring operations. To address this sampling and analysis bottleneck and decrease the time needed to recover from an anthrax contamination event, this study investigates the use of composite sampling. Pooling or compositing of samples is an established technique to reduce the number of analyses required, and its use for anthrax spore sampling has recently been investigated. However, use of composite sampling in an anthrax spore remediation event will require well-documented and accepted methods. In particular, previous composite sampling studies have focused on sampling from hard surfaces; data on soil sampling are required to extend the procedure to outdoor use. Further, we must consider whether combining liquid samples, thus increasing the volume, lowers the sensitivity of detection and produces false negatives. In this study, methods to composite bacterial spore samples from soil are demonstrated. B. subtilis spore suspensions were used as a surrogate for anthrax spores. Two soils (Arizona Test Dust and sterilized potting soil) were contaminated and spore recovery with composites was shown to match individual sample performance. Results show that dilution can be overcome by concentrating bacterial spores using standard filtration methods. This study shows that composite sampling can be a viable method of pooling samples to reduce the number of analysis that must be performed during anthrax spore remediation. PMID:26714315

Reliable Quantification of the Potential for Equations Based on Spot Urine Samples to Estimate Population Salt Intake: Protocol for a Systematic Review and Meta-Analysis.

PubMed

Huang, Liping; Crino, Michelle; Wu, Jason Hy; Woodward, Mark; Land, Mary-Anne; McLean, Rachael; Webster, Jacqui; Enkhtungalag, Batsaikhan; Nowson, Caryl A; Elliott, Paul; Cogswell, Mary; Toft, Ulla; Mill, Jose G; Furlanetto, Tania W; Ilich, Jasminka Z; Hong, Yet Hoi; Cohall, Damian; Luzardo, Leonella; Noboa, Oscar; Holm, Ellen; Gerbes, Alexander L; Senousy, Bahaa; Pinar Kara, Sonat; Brewster, Lizzy M; Ueshima, Hirotsugu; Subramanian, Srinivas; Teo, Boon Wee; Allen, Norrina; Choudhury, Sohel Reza; Polonia, Jorge; Yasuda, Yoshinari; Campbell, Norm Rc; Neal, Bruce; Petersen, Kristina S

2016-09-21

Methods based on spot urine samples (a single sample at one time-point) have been identified as a possible alternative approach to 24-hour urine samples for determining mean population salt intake. The aim of this study is to identify a reliable method for estimating mean population salt intake from spot urine samples. This will be done by comparing the performance of existing equations against one other and against estimates derived from 24-hour urine samples. The effects of factors such as ethnicity, sex, age, body mass index, antihypertensive drug use, health status, and timing of spot urine collection will be explored. The capacity of spot urine samples to measure change in salt intake over time will also be determined. Finally, we aim to develop a novel equation (or equations) that performs better than existing equations to estimate mean population salt intake. A systematic review and meta-analysis of individual participant data will be conducted. A search has been conducted to identify human studies that report salt (or sodium) excretion based upon 24-hour urine samples and spot urine samples. There were no restrictions on language, study sample size, or characteristics of the study population. MEDLINE via OvidSP (1946-present), Premedline via OvidSP, EMBASE, Global Health via OvidSP (1910-present), and the Cochrane Library were searched, and two reviewers identified eligible studies. The authors of these studies will be invited to contribute data according to a standard format. Individual participant records will be compiled and a series of analyses will be completed to: (1) compare existing equations for estimating 24-hour salt intake from spot urine samples with 24-hour urine samples, and assess the degree of bias according to key demographic and clinical characteristics; (2) assess the reliability of using spot urine samples to measure population changes in salt intake overtime; and (3) develop a novel equation that performs better than existing equations to estimate mean population salt intake. The search strategy identified 538 records; 100 records were obtained for review in full text and 73 have been confirmed as eligible. In addition, 68 abstracts were identified, some of which may contain data eligible for inclusion. Individual participant data will be requested from the authors of eligible studies. Many equations for estimating salt intake from spot urine samples have been developed and validated, although most have been studied in very specific settings. This meta-analysis of individual participant data will enable a much broader understanding of the capacity for spot urine samples to estimate population salt intake.

Does self-selection affect samples' representativeness in online surveys? An investigation in online video game research.

PubMed

Khazaal, Yasser; van Singer, Mathias; Chatton, Anne; Achab, Sophia; Zullino, Daniele; Rothen, Stephane; Khan, Riaz; Billieux, Joel; Thorens, Gabriel

2014-07-07

The number of medical studies performed through online surveys has increased dramatically in recent years. Despite their numerous advantages (eg, sample size, facilitated access to individuals presenting stigmatizing issues), selection bias may exist in online surveys. However, evidence on the representativeness of self-selected samples in online studies is patchy. Our objective was to explore the representativeness of a self-selected sample of online gamers using online players' virtual characters (avatars). All avatars belonged to individuals playing World of Warcraft (WoW), currently the most widely used online game. Avatars' characteristics were defined using various games' scores, reported on the WoW's official website, and two self-selected samples from previous studies were compared with a randomly selected sample of avatars. We used scores linked to 1240 avatars (762 from the self-selected samples and 478 from the random sample). The two self-selected samples of avatars had higher scores on most of the assessed variables (except for guild membership and exploration). Furthermore, some guilds were overrepresented in the self-selected samples. Our results suggest that more proficient players or players more involved in the game may be more likely to participate in online surveys. Caution is needed in the interpretation of studies based on online surveys that used a self-selection recruitment procedure. Epidemiological evidence on the reduced representativeness of sample of online surveys is warranted.

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

PubMed

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

2016-05-01

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

Intraosseous samples can be used for creatinine measurements--an experimental study in the anaesthetised pig.

PubMed

Strandberg, Gunnar; Lipcsey, Miklós; Eriksson, Mats; Larsson, Anders

2014-01-01

Intraosseous (IO) access is a valuable tool in prehospital locations and in emergency departments when other forms of vascular access are unavailable. Creatinine is often used for dose adjustment of drugs that may be administered through intraosseous cannulae. We aimed to study the possibility of analysing creatinine in intraosseous samples and study the accuracy and precision of such measurements. Eight pigs with endotoxin induced septic shock were sampled hourly for six hours and analysed for plasma creatinine. Samples were collected from arterial, venous, and IO cannulae. There was an increase in creatinine values during the later part of the experiment. The coefficients of variation between the three sampling sites were less than 10% at all sampling times. Based on our findings intraosseous samples can be used for creatinine determination in emergency settings.

Water-quality, streamflow, and ancillary data for nutrients in streams and rivers across the nation, 1992-2001

USGS Publications Warehouse

Mueller, David K.; Spahr, Norman E.

2005-01-01

Introduction: This report is the companion data report for: Nutrients in Streams and Rivers Across the Nation - 1992-2001 (D.K. Mueller and N.E. Spahr, U.S. Geological Survey written commun., 2005). The data contained in this report were collected as part of the National Water-Quality Assessment (NAWQA) Program. Investigations were conducted in 51 large river basins and aquifer systems, which are referred to as 'study units.' Implementation of study-unit investigations were phased so that high-intensity sampling occurred in about one-third of the study units at a time. Investigations in the first 20 study units began in 1991, and stream sampling began in 1992; however, most samples were collected during water years 1993-95. (Water year is defined as the period from October through September and is identified by the year in which it ends.) A second group of 16 study-unit investigations began in 1994, with most of the sampling completed during water years 1996-98. A third group, consisting of 15 study units, began in 1997 with most of the data collected during water years 1999-2001. At some sites, additional sampling continued after the high-intensity time period. Gilliom and others (1995) provide additional information about study-unit sampling design. Additional information about the NAWQA program is available at http://water.usgs.gov/nawqa/index.html.

What is an adequate sample size? Operationalising data saturation for theory-based interview studies.

PubMed

Francis, Jill J; Johnston, Marie; Robertson, Clare; Glidewell, Liz; Entwistle, Vikki; Eccles, Martin P; Grimshaw, Jeremy M

2010-12-01

In interview studies, sample size is often justified by interviewing participants until reaching 'data saturation'. However, there is no agreed method of establishing this. We propose principles for deciding saturation in theory-based interview studies (where conceptual categories are pre-established by existing theory). First, specify a minimum sample size for initial analysis (initial analysis sample). Second, specify how many more interviews will be conducted without new ideas emerging (stopping criterion). We demonstrate these principles in two studies, based on the theory of planned behaviour, designed to identify three belief categories (Behavioural, Normative and Control), using an initial analysis sample of 10 and stopping criterion of 3. Study 1 (retrospective analysis of existing data) identified 84 shared beliefs of 14 general medical practitioners about managing patients with sore throat without prescribing antibiotics. The criterion for saturation was achieved for Normative beliefs but not for other beliefs or studywise saturation. In Study 2 (prospective analysis), 17 relatives of people with Paget's disease of the bone reported 44 shared beliefs about taking genetic testing. Studywise data saturation was achieved at interview 17. We propose specification of these principles for reporting data saturation in theory-based interview studies. The principles may be adaptable for other types of studies.

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

PubMed

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

2014-09-01

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

THE NORTH CAROLINA HERALD PILOT STUDY

EPA Science Inventory

The sampling design for the National Children's Study (NCS) calls for a population-based, multi-stage, clustered household sampling approach. The full sample is designed to be representative of both urban and rural births in the United States, 2007-2011. While other sur...

Evaluation of Surface Sampling for Bacillus Spores Using ...

EPA Pesticide Factsheets

Journal Article In this study, commercially-available domestic cleaning robots were evaluated for spore surface sampling efficiency on common indoor surfaces. The current study determined the sampling efficiency of each robot, without modifying the sensors, algorithms, or logics set by the manufacturers.

40 CFR 761.323 - Sample preparation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROHIBITIONS Self-Implementing Alternative Extraction and Chemical Analysis Procedures for Non-liquid PCB Remediation Waste Samples § 761.323 Sample preparation. (a) The comparison study requires analysis of a... of use in this chemical extraction and chemical analysis comparison study, a person may adjust PCB...

Systematic Evaluation of the Use of Human Plasma and Serum for Mass-Spectrometry-Based Shotgun Proteomics.

PubMed

Lan, Jiayi; Núñez Galindo, Antonio; Doecke, James; Fowler, Christopher; Martins, Ralph N; Rainey-Smith, Stephanie R; Cominetti, Ornella; Dayon, Loïc

2018-04-06

Over the last two decades, EDTA-plasma has been used as the preferred sample matrix for human blood proteomic profiling. Serum has also been employed widely. Only a few studies have assessed the difference and relevance of the proteome profiles obtained from plasma samples, such as EDTA-plasma or lithium-heparin-plasma, and serum. A more complete evaluation of the use of EDTA-plasma, heparin-plasma, and serum would greatly expand the comprehensiveness of shotgun proteomics of blood samples. In this study, we evaluated the use of heparin-plasma with respect to EDTA-plasma and serum to profile blood proteomes using a scalable automated proteomic pipeline (ASAP 2 ). The use of plasma and serum for mass-spectrometry-based shotgun proteomics was first tested with commercial pooled samples. The proteome coverage consistency and the quantitative performance were compared. Furthermore, protein measurements in EDTA-plasma and heparin-plasma samples were comparatively studied using matched sample pairs from 20 individuals from the Australian Imaging, Biomarkers and Lifestyle (AIBL) Study. We identified 442 proteins in common between EDTA-plasma and heparin-plasma samples. Overall agreement of the relative protein quantification between the sample pairs demonstrated that shotgun proteomics using workflows such as the ASAP 2 is suitable in analyzing heparin-plasma and that such sample type may be considered in large-scale clinical research studies. Moreover, the partial proteome coverage overlaps (e.g., ∼70%) showed that measures from heparin-plasma could be complementary to those obtained from EDTA-plasma.

Variability of indoor fungal microbiome of green and non-green low-income homes in Cincinnati, Ohio.

PubMed

Coombs, Kanistha; Taft, Diana; Ward, Doyle V; Green, Brett J; Chew, Ginger L; Shamsaei, Behrouz; Meller, Jaroslaw; Indugula, Reshmi; Reponen, Tiina

2018-01-01

"Green" housing is designed to use low-impact materials, increase energy efficiency and improve occupant health. However, little is known about the indoor mycobiome of green homes. The current study is a subset of a multicenter study that aims to investigate the indoor environment of green homes and the respiratory health of asthmatic children. In the current study, the mycobiome in air, bed dust and floor dust was compared between green (study site) and non-green (control site), low-income homes in Cincinnati, Ohio. The samples were collected at baseline (within four months following renovation), and 12months after the baseline at the study site. Parallel sample collection was conducted in non-green control homes. Air samples were collected by PM2.5 samplers over 5-days. Bed and floor dust samples were vacuumed after the air sampling was completed. The DNA sample extracts were analyzed using ITS amplicon sequencing. Analysis indicated that there was no clear trend in the fungal communities between green and non-green homes. Instead, fungal community differences were greatest between sample types - air, bed, and floor. Microbial communities also changed substantially between sampling intervals in both green and non-green homes for all sample types, potentially indicating that there was very little stability in the mycobiomes. Research gaps remain regarding how indoor mycobiome fluctuates over time. Longer follow-up periods might elucidate the effect of green renovation on microbial load in buildings. Copyright © 2017 Elsevier B.V. All rights reserved.

Exposure to microbial components and allergens in population studies: a comparison of two house dust collection methods applied by participants and fieldworkers.

PubMed

Schram-Bijkerk, D; Doekes, G; Boeve, M; Douwes, J; Riedler, J; Ublagger, E; von Mutius, E; Benz, M; Pershagen, G; Wickman, M; Alfvén, T; Braun-Fahrländer, C; Waser, M; Brunekreef, B

2006-12-01

Dust collection by study participants instead of fieldworkers would be a practical and cost-effective alternative in large-scale population studies estimating exposure to indoor allergens and microbial agents. We aimed to compare dust weights and biological agent levels in house dust samples taken by study participants with nylon socks, with those in samples taken by fieldworkers using the sampling nozzle of the Allergology Laboratory Copenhagen (ALK). In homes of 216 children, parents and fieldworkers collected house dust within the same year. Dust samples were analyzed for levels of allergens, endotoxin, (1-->3)-beta-D-glucans and fungal extracellular polysaccharides (EPS). Socks appeared to yield less dust from mattresses at relatively low dust amounts and more dust at high dust amounts than ALK samples. Correlations between the methods ranged from 0.47-0.64 for microbial agents and 0.64-0.87 for mite and pet allergens. Cat allergen levels were two-fold lower and endotoxin levels three-fold higher in socks than in ALK samples. Levels of allergens and microbial agents in sock samples taken by study participants are moderately to highly correlated to levels in ALK samples taken by fieldworkers. Absolute levels may differ, probably because of differences in the method rather than in the person who performed the sampling. Practical Implications Dust collection by participants is a reliable and practical option for allergen and microbial agent exposure assessment. Absolute levels of biological agents are not (always) comparable between studies using different dust collection methods, even when expressed per gram dust, because of potential differences in particle-size constitution of the collected dust.

Effect of variable rates of daily sampling of fly larvae on decomposition and carrion insect community assembly: implications for forensic entomology field study protocols.

PubMed

Michaud, Jean-Philippe; Moreau, Gaétan

2013-07-01

Experimental protocols in forensic entomology successional field studies generally involve daily sampling of insects to document temporal changes in species composition on animal carcasses. One challenge with that method has been to adjust the sampling intensity to obtain the best representation of the community present without affecting the said community. To this date, little is known about how such investigator perturbations affect decomposition-related processes. Here, we investigated how different levels of daily sampling of fly eggs and fly larvae affected, over time, carcass decomposition rate and the carrion insect community. Results indicated that a daily sampling of <5% of the egg and larvae volumes present on a carcass, a sampling intensity believed to be consistent with current accepted practices in successional field studies, had little effect overall. Higher sampling intensities, however, slowed down carcass decomposition, affected the abundance of certain carrion insects, and caused an increase in the volume of eggs laid by dipterans. This study suggests that the carrion insect community not only has a limited resilience to recurrent perturbations but that a daily sampling intensity equal to or <5% of the egg and larvae volumes appears adequate to ensure that the system is representative of unsampled conditions. Hence we propose that this threshold be accepted as best practice in future forensic entomology successional field studies.

DNA barcoding using skin exuviates can improve identification and biodiversity studies of snakes.

PubMed

Khedkar, Trupti; Sharma, Rashmi; Tiknaik, Anita; Khedkar, Gulab; Naikwade, Bhagwat S; Ron, Tetsuzan Benny; Haymer, David

2016-01-01

Snakes represent a taxonomically underdeveloped group of animals in India with a lack of experts and incomplete taxonomic descriptions being the main deterrents to advances in this area. Molecular taxonomic approaches using DNA barcoding could aid in snake identification as well as studies of biodiversity. Here a non-invasive sampling method using DNA barcoding is tested using skin exuviates. Taxonomically authenticated samples were collected and tested for validation and comparisons to unknown snake exuviate samples. This approach was also used to construct the first comprehensive study targeting the snake species from Maharashtra state in India. A total of 92 skin exuviate samples were collected and tested for this study. Of these, 81 samples were successfully DNA barcoded and compared with unknown samples for assignment of taxonomic identity. Good quality DNA was obtained irrespective of age and quality of the exuviate material, and all unknown samples were successfully identified. A total of 23 species of snakes were identified, six of which were in the list of Endangered species (Red Data Book). Intra- and inter-specific distance values were also calculated, and these were sufficient to allow discrimination among species and between species without ambiguity in most cases. Two samples were suspected to represent cryptic species based on deep K2P divergence values (>3%), and one sample could be identified to the genus level only. Eleven samples failed to amplify COI sequences, suggesting the need for alternative PCR primer pairs. This study clearly documents how snake skin exuviates can be used for DNA barcoding, estimates of diversity and population genetic structuring in a noninvasive manner.

Improvement in the stability of serum samples stored in an automated refrigerated module.

PubMed

Parra-Robert, Marina; Rico-Santana, Naira; Alcaraz-Quiles, José; Sandalinas, Silvia; Fernández, Esther; Falcón, Isabel; Pérez-Riedweg, Margarita; Bedini, Josep Lluís

2016-12-01

In clinical laboratories it is necessary to know for how long the analytes are stable in the samples with specific storage conditions. Our laboratory has implemented the new Aptio Automation System (AAS) (Siemens Healthcare Diagnostics) where the analyzed samples are stored in a refrigerated storage module (RSM) after being sealed. The aim of the study was to evaluate the stability of serum samples with the AAS and comparing the results with a previous study using a conventional refrigerated system. Serum samples from a total of 50 patients were collected and for each of them 27 biochemical analytes were analyzed. The samples were divided in 5 sets of 10 samples. Each set was re-analyzed at one of the following times: 24, 48, 72, 96 and 120h. Stability was evaluated according to the Total Limit of Change (TLC) criteria, which combine both analytical and biologic variation. A total of 26 out of 27 analytes were stable at the end of the study according to TLC criteria. Lactate dehydrogenase was not stable at 48h observing a decrease in its concentration until the end of the study. In the previous study (conventional storage system) 9 biochemical analytes were not stable with an increase of their levels due to the evaporation process. The RSM connected to the AAS improves the stability of serum samples. This system avoids the evaporation process due to the sealing of samples and allows better control of the samples during their storage. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Comparison of Fecal Collection Methods for Microbiota Studies in Bangladesh

PubMed Central

Chen, Jun; Kibriya, Muhammad G.; Chen, Yu; Islam, Tariqul; Eunes, Mahbubul; Ahmed, Alauddin; Naher, Jabun; Rahman, Anisur; Amir, Amnon; Shi, Jianxin; Abnet, Christian C.; Nelson, Heidi; Knight, Rob; Chia, Nicholas; Ahsan, Habibul; Sinha, Rashmi

2017-01-01

ABSTRACT To our knowledge, fecal microbiota collection methods have not been evaluated in low- and middle-income countries. Therefore, we evaluated five different fecal sample collection methods for technical reproducibility, stability, and accuracy within the Health Effects of Arsenic Longitudinal Study (HEALS) in Bangladesh. Fifty participants from the HEALS provided fecal samples in the clinic which were aliquoted into no solution, 95% ethanol, RNAlater, postdevelopment fecal occult blood test (FOBT) cards, and fecal immunochemical test (FIT) tubes. Half of the aliquots were frozen immediately at −80°C (day 0) and the remaining samples were left at ambient temperature for 96 h and then frozen (day 4). Intraclass correlation coefficients (ICC) were calculated for the relative abundances of the top three phyla, for two alpha diversity measures, and for four beta diversity measures. The duplicate samples had relatively high ICCs for technical reproducibility at day 0 and day 4 (range, 0.79 to 0.99). The FOBT card and samples preserved in RNAlater and 95% ethanol had the highest ICCs for stability over 4 days. The FIT tube had lower stability measures overall. In comparison to the “gold standard” method using immediately frozen fecal samples with no solution, the ICCs for many of the microbial metrics were low, but the rank order appeared to be preserved as seen by the Spearman correlation. The FOBT cards, 95% ethanol, and RNAlater were effective fecal preservatives. These fecal collection methods are optimal for future cohort studies, particularly in low- and middle-income countries. IMPORTANCE The collection of fecal samples in prospective cohort studies is essential to provide the opportunity to study the effect of the human microbiota on numerous health conditions. However, these collection methods have not been adequately tested in low- and middle-income countries. We present estimates of technical reproducibility, stability at ambient temperature for 4 days, and accuracy comparing a “gold standard” for fecal samples in no solution, 95% ethanol, RNAlater, postdevelopment fecal occult blood test cards, and fecal immunochemical test tubes in a study conducted in Bangladesh. Fecal occult blood test cards and fecal samples stored in 95% ethanol or RNAlater adequately preserve fecal samples in this setting. Therefore, new studies in low- and middle-income countries should include collection of fecal samples using fecal occult blood test cards, 95% ethanol, or RNAlater for prospective cohort studies. PMID:28258145

Preanalytical Errors in Hematology Laboratory- an Avoidable Incompetence.

PubMed

HarsimranKaur, Vikram Narang; Selhi, Pavneet Kaur; Sood, Neena; Singh, Aminder

2016-01-01

Quality assurance in the hematology laboratory is a must to ensure laboratory users of reliable test results with high degree of precision and accuracy. Even after so many advances in hematology laboratory practice, pre-analytical errors remain a challenge for practicing pathologists. This study was undertaken with an objective to evaluate the types and frequency of preanalytical errors in hematology laboratory of our center. All the samples received in the Hematology Laboratory of Dayanand Medical College and Hospital, Ludhiana, India over a period of one year (July 2013-July 2014) were included in the study and preanalytical variables like clotted samples, quantity not sufficient, wrong sample, without label, wrong label were studied. Of 471,006 samples received in the laboratory, preanalytical errors, as per the above mentioned categories was found in 1802 samples. The most common error was clotted samples (1332 samples, 0.28% of the total samples) followed by quantity not sufficient (328 sample, 0.06%), wrong sample (96 samples, 0.02%), without label (24 samples, 0.005%) and wrong label (22 samples, 0.005%). Preanalytical errors are frequent in laboratories and can be corrected by regular analysis of the variables involved. Rectification can be done by regular education of the staff.

The Neighbourhood Effects on Health and Well-being (NEHW) study.

PubMed

O'Campo, Patricia; Wheaton, Blair; Nisenbaum, Rosane; Glazier, Richard H; Dunn, James R; Chambers, Catharine

2015-01-01

Many cross-sectional studies of neighbourhood effects on health do not employ strong study design elements. The Neighbourhood Effects on Health and Well-being (NEHW) study, a random sample of 2412 English-speaking Toronto residents (age 25-64), utilises strong design features for sampling neighbourhoods and individuals, characterising neighbourhoods using a variety of data sources, measuring a wide range of health outcomes, and for analysing cross-level interactions. We describe here methodological issues that shaped the design and analysis features of the NEHW study to ensure that, while a cross-sectional sample, it will advance the quality of evidence emerging from observational studies. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

STUDY OF HOME DEMONSTRATION UNITS IN A SAMPLE OF 27 COUNTIES IN NEW YORK STATE, NUMBER 3.

ERIC Educational Resources Information Center

ALEXANDER, FRANK D.; HARSHAW, JEAN

AN EXPLORATORY STUDY EXAMINED CHARACTERISTICS OF 1,128 HOME DEMONSTRATION UNITS TO SUGGEST HYPOTHESES AND SCOPE FOR A MORE INTENSIVE STUDY OF A SMALL SAMPLE OF UNITS, AND TO PROVIDE GUIDANCE IN SAMPLING. DATA WERE OBTAINED FROM A SPECIALLY DESIGNED MEMBERSHIP CARD USED IN 1962. UNIT SIZE AVERAGED 23.6 MEMBERS BUT THE RANGE WAS FAIRLY GREAT. A NEED…

Selected Factors Related to Selective Service Rejection and Rejection Rate in Delaware (1967): A Study of the Characteristics of Young Men Failing to Meet Mental Qualifications for Military Service.

ERIC Educational Resources Information Center

Price, Jay R.

This study sought information about selective service rejection in Delaware, specifically rejectee characteristics, reasons for rejection, and the high rejection rate in Delaware. The basic design was a modified case study method in which a sample of individual records were examined. Differences between this sample and national samples were tested…

The Center for Epidemiologic Studies Depression Scale: Factor Validity and Reliability in a French Sample of Adolescents with Intellectual Disability

ERIC Educational Resources Information Center

Maiano, Christophe; Morin, Alexandre J. S.; Begarie, Jerome

2011-01-01

The purpose of this study was to test the factor validity and reliability of the Center for Epidemiologic Studies Depression Scale (CES-D) within a sample of adolescents with mild to moderate Intellectual Disability (ID). A total sample of 189 adolescents (121 boys and 68 girls), aged between 12 and 18 years old, with mild to moderate ID were…

Effects of sample size on estimates of population growth rates calculated with matrix models.

PubMed

Fiske, Ian J; Bruna, Emilio M; Bolker, Benjamin M

2008-08-28

Matrix models are widely used to study the dynamics and demography of populations. An important but overlooked issue is how the number of individuals sampled influences estimates of the population growth rate (lambda) calculated with matrix models. Even unbiased estimates of vital rates do not ensure unbiased estimates of lambda-Jensen's Inequality implies that even when the estimates of the vital rates are accurate, small sample sizes lead to biased estimates of lambda due to increased sampling variance. We investigated if sampling variability and the distribution of sampling effort among size classes lead to biases in estimates of lambda. Using data from a long-term field study of plant demography, we simulated the effects of sampling variance by drawing vital rates and calculating lambda for increasingly larger populations drawn from a total population of 3842 plants. We then compared these estimates of lambda with those based on the entire population and calculated the resulting bias. Finally, we conducted a review of the literature to determine the sample sizes typically used when parameterizing matrix models used to study plant demography. We found significant bias at small sample sizes when survival was low (survival = 0.5), and that sampling with a more-realistic inverse J-shaped population structure exacerbated this bias. However our simulations also demonstrate that these biases rapidly become negligible with increasing sample sizes or as survival increases. For many of the sample sizes used in demographic studies, matrix models are probably robust to the biases resulting from sampling variance of vital rates. However, this conclusion may depend on the structure of populations or the distribution of sampling effort in ways that are unexplored. We suggest more intensive sampling of populations when individual survival is low and greater sampling of stages with high elasticities.

Do Research Findings Apply to My Students? Examining Study Samples and Sampling

ERIC Educational Resources Information Center

Cook, Bryan G.; Cook, Lysandra

2017-01-01

Special educators are urged to use research findings to inform their instruction in order to improve student outcomes. However, it can be difficult to tell whether and how research findings apply to one's own students. In this article, we discuss how special educators can consider the samples and the sampling methods in studies to examine the…

The Relationship between Sample Sizes and Effect Sizes in Systematic Reviews in Education

ERIC Educational Resources Information Center

Slavin, Robert; Smith, Dewi

2009-01-01

Research in fields other than education has found that studies with small sample sizes tend to have larger effect sizes than those with large samples. This article examines the relationship between sample size and effect size in education. It analyzes data from 185 studies of elementary and secondary mathematics programs that met the standards of…

Comparative Financial Statistics for Public Two-Year Colleges: FY 1995 Peer Groups Sample.

ERIC Educational Resources Information Center

Meeker, Bradley

Comparative financial information derived from a national sample of 405 two-year colleges is presented in this report for fiscal year 1994-95, including data for the national sample and for 6groups of peer institutions. The first section provides introductory information on the annual study, discussing the study sample and the use of study…

A re-evaluation of a case-control model with contaminated controls for resource selection studies

Treesearch

Christopher T. Rota; Joshua J. Millspaugh; Dylan C. Kesler; Chad P. Lehman; Mark A. Rumble; Catherine M. B. Jachowski

2013-01-01

A common sampling design in resource selection studies involves measuring resource attributes at sample units used by an animal and at sample units considered available for use. Few models can estimate the absolute probability of using a sample unit from such data, but such approaches are generally preferred over statistical methods that estimate a relative probability...

Are Apparent Sex Differences in Mean IQ Scores Created in Part by Sample Restriction and Increased Male Variance?

ERIC Educational Resources Information Center

Dykiert, Dominika; Gale, Catharine R.; Deary, Ian J.

2009-01-01

This study investigated the possibility that apparent sex differences in IQ are at least partly created by the degree of sample restriction from the baseline population. We used a nationally representative sample, the 1970 British Cohort Study. Sample sizes varied from 6518 to 11,389 between data-collection sweeps. Principal components analysis of…

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR FIELD COLLECTION OF INDOOR FLOOR SAMPLES AND POST FIELD SAMPLE HANDLING (UA-F-7.1)

EPA Science Inventory

The purpose of this SOP is to establish a uniform procedure for the collection of indoor floor dust samples in the field. This procedure was followed to ensure consistent data retrieval of dust samples during the Arizona NHEXAS project and the "Border" study. Keywords: field; va...

[Assessment of biological sampling's quality in a medical laboratory: case of Côte d' Ivoire Institute Pasteur].

PubMed

Kouassi-M'Bengue, Alphonsine; Koffi, Stephane; Manizan, Pascale; Ouattara, Abdoulaye; N'Douba, Adele Kacou; Dosso, Mireille

2008-01-01

Assurance quality is important in medical laboratory, but in Africa, few laboratories are involved in this process. The aim of this study was to assess biological sampling's quality in a bacteriological laboratory. A cross sectional study was undertaken in medical bacteriological laboratory of Côte d' Ivoire Institute Pasteur during 6 months. All urines, saddles, and bronchial expectorations collected from ambulatory patients during this period were included in the study. The quality of urine's, saddles and bronchial expectorations' sampling for a bacteriological analysis was evaluated. An interview based on Guidelines of good laboratories practices and referential ISO 15189 was used. A total of 300 samples were indexed. On a total of 300 recorded biological samples, 224 (74.7%) were not in conformity. In 87.5% of the cases of nonconformities, an antibiotic's treatment were preliminary instituted before the sampling. Corrective actions were carried in the laboratory on 30 samples with 56.6% for the urines, 26.7% for the saddles and 16.7% for the bronchial expectorations. At the end of this study, it arises that the quality of the biological sampling received at the medical bacteriology laboratory need to be improved.

The effect of carbon black filler to the mechanical properties of natural rubber as base isolation system

NASA Astrophysics Data System (ADS)

Ismail, R.; Mahadi, Z. A.; Ishak, I. S.

2018-04-01

This paper presented the study on the effect of carbon black as filler to the mechanical properties of natural rubber for base isolation system. This study used the five formulations with the different amount of carbon black filler for every sample. The samples were tested for tensile, hardness and resilience test. The samples were cured or vulcanized at 1500C for 23 minutes for every formulation. The filler used in this study was the carbon black filler with type N660. The tensile test was done to determine the ability of the sample in term of the elongation with the load at break. The hardness test, it has been done to determine the ability of the sample to resist the load. This hardness was measured in the unit of IRHD. The resilience test was being done to determine the properties of the sample in term of rebound characteristics. The finding of this study showed that, the high the loading of carbon black filler, the high the tensile strength of the sample and the high the hardness of the sample. In term of resilience, it was inversely proportional to the loading of the carbon black filler.

The Portuguese adaptation of the Gudjonsson Suggestibility Scale (GSS1) in a sample of inmates.

PubMed

Pires, Rute; Silva, Danilo R; Ferreira, Ana Sousa

2014-01-01

This paper comprises two studies which address the validity of the Portuguese adaptation of the Gudjonsson Suggestibility Scale, GSS1. In study 1, the means and standard deviations for the suggestibility results of a sample of Portuguese inmates (N=40, Mage=37.5 years, SD=8.1) were compared to those of a sample of Icelandic inmates (Gudjonsson, 1997; Gudjonsson & Sigurdsson, 1996). Portuguese inmates' results were in line with the original results. In study 2, the means and standard deviations for the suggestibility results of the sample of Portuguese inmates were compared to those of a general Portuguese population sample (N=57, Mage=36.1 years, SD=12.7). The forensic sample obtained significantly higher scores in suggestibility measures than the general population sample. ANOVA confirmed that the increased suggestibility in the inmates sample was due to the limited memory capacity of this latter group. Given that the results of both studies 1 and 2 are in keeping with the author's original results (Gudjonsson, 1997), this may be regarded as a confirmation of the validity of the Portuguese GSS1. Copyright © 2013 Elsevier Ltd. All rights reserved.

Molecular identification of isolated fungi, microbial and heavy metal contamination of canned meat products sold in Riyadh, Saudi Arabia

PubMed Central

Nasser, Laila A.

2014-01-01

Several studies have shown that canned meat products may be contaminated with fungal elements, bacteria and even heavy metals which may occur during the transportation, storage and handling processes. We conducted this study to determine the fungal, microbial and heavy metal contents of canned meats in Saudi Arabia. Of the 13 canned meat samples studied, Aspergillus and Penicillium were found in more than 70% of the total samples. Sequences of Penicillium species isolated from meat samples generated a phylogenetic tree which shows that the studied isolates were clustered in four groups. No bacterial contamination was noted in all of the samples. Nine of the 13 samples had iron concentrations above the permissible limit. All samples had zinc and copper levels below the maximum permissible limit. Four samples had cadmium levels above the maximum permissible level. All samples had levels of lead above the maximum permissible levels. These results indicate that fungal elements and higher levels of heavy metals such as lead and cadmium can be found in canned meat products. This may pose as a real danger to consumers, since canned meat products are readily accessible and convenient in Saudi Arabia. PMID:26288552

Stratified randomization controls better for batch effects in 450K methylation analysis: a cautionary tale.

PubMed

Buhule, Olive D; Minster, Ryan L; Hawley, Nicola L; Medvedovic, Mario; Sun, Guangyun; Viali, Satupaitea; Deka, Ranjan; McGarvey, Stephen T; Weeks, Daniel E

2014-01-01

Batch effects in DNA methylation microarray experiments can lead to spurious results if not properly handled during the plating of samples. Two pilot studies examining the association of DNA methylation patterns across the genome with obesity in Samoan men were investigated for chip- and row-specific batch effects. For each study, the DNA of 46 obese men and 46 lean men were assayed using Illumina's Infinium HumanMethylation450 BeadChip. In the first study (Sample One), samples from obese and lean subjects were examined on separate chips. In the second study (Sample Two), the samples were balanced on the chips by lean/obese status, age group, and census region. We used methylumi, watermelon, and limma R packages, as well as ComBat, to analyze the data. Principal component analysis and linear regression were, respectively, employed to identify the top principal components and to test for their association with the batches and lean/obese status. To identify differentially methylated positions (DMPs) between obese and lean males at each locus, we used a moderated t-test. Chip effects were effectively removed from Sample Two but not Sample One. In addition, dramatic differences were observed between the two sets of DMP results. After "removing" batch effects with ComBat, Sample One had 94,191 probes differentially methylated at a q-value threshold of 0.05 while Sample Two had zero differentially methylated probes. The disparate results from Sample One and Sample Two likely arise due to the confounding of lean/obese status with chip and row batch effects. Even the best possible statistical adjustments for batch effects may not completely remove them. Proper study design is vital for guarding against spurious findings due to such effects.

Stratified randomization controls better for batch effects in 450K methylation analysis: a cautionary tale

PubMed Central

Buhule, Olive D.; Minster, Ryan L.; Hawley, Nicola L.; Medvedovic, Mario; Sun, Guangyun; Viali, Satupaitea; Deka, Ranjan; McGarvey, Stephen T.; Weeks, Daniel E.

2014-01-01

Background: Batch effects in DNA methylation microarray experiments can lead to spurious results if not properly handled during the plating of samples. Methods: Two pilot studies examining the association of DNA methylation patterns across the genome with obesity in Samoan men were investigated for chip- and row-specific batch effects. For each study, the DNA of 46 obese men and 46 lean men were assayed using Illumina's Infinium HumanMethylation450 BeadChip. In the first study (Sample One), samples from obese and lean subjects were examined on separate chips. In the second study (Sample Two), the samples were balanced on the chips by lean/obese status, age group, and census region. We used methylumi, watermelon, and limma R packages, as well as ComBat, to analyze the data. Principal component analysis and linear regression were, respectively, employed to identify the top principal components and to test for their association with the batches and lean/obese status. To identify differentially methylated positions (DMPs) between obese and lean males at each locus, we used a moderated t-test. Results: Chip effects were effectively removed from Sample Two but not Sample One. In addition, dramatic differences were observed between the two sets of DMP results. After “removing” batch effects with ComBat, Sample One had 94,191 probes differentially methylated at a q-value threshold of 0.05 while Sample Two had zero differentially methylated probes. The disparate results from Sample One and Sample Two likely arise due to the confounding of lean/obese status with chip and row batch effects. Conclusion: Even the best possible statistical adjustments for batch effects may not completely remove them. Proper study design is vital for guarding against spurious findings due to such effects. PMID:25352862

Efficacy of adrenal venous sampling is increased by point of care cortisol analysis

PubMed Central

Viste, Kristin; Grytaas, Marianne A; Jørstad, Melissa D; Jøssang, Dag E; Høyden, Eivind N; Fotland, Solveig S; Jensen, Dag K; Løvås, Kristian; Thordarson, Hrafnkell; Almås, Bjørg; Mellgren, Gunnar

2013-01-01

Primary aldosteronism (PA) is a common cause of secondary hypertension and is caused by unilateral or bilateral adrenal disease. Treatment options depend on whether the disease is lateralized or not, which is preferably evaluated with selective adrenal venous sampling (AVS). This procedure is technically challenging, and obtaining representative samples from the adrenal veins can prove difficult. Unsuccessful AVS procedures often require reexamination. Analysis of cortisol during the procedure may enhance the success rate. We invited 21 consecutive patients to participate in a study with intra-procedural point of care cortisol analysis. When this assay showed nonrepresentative sampling, new samples were drawn after redirection of the catheter. The study patients were compared using the 21 previous procedures. The intra-procedural cortisol assay increased the success rate from 10/21 patients in the historical cohort to 17/21 patients in the study group. In four of the 17 successful procedures, repeated samples needed to be drawn. Successful sampling at first attempt improved from the first seven to the last seven study patients. Point of care cortisol analysis during AVS improves success rate and reduces the need for reexaminations, in accordance with previous studies. Successful AVS is crucial when deciding which patients with PA will benefit from surgical treatment. PMID:24169597

Biological data extraction from imagery - How far can we go? A case study from the Mid-Atlantic Ridge.

PubMed

Cuvelier, Daphne; de Busserolles, Fanny; Lavaud, Romain; Floc'h, Estelle; Fabri, Marie-Claire; Sarradin, Pierre-Marie; Sarrazin, Jozée

2012-12-01

In the past few decades, hydrothermal vent research has progressed immensely, resulting in higher-quality samples and long-term studies. With time, scientists are becoming more aware of the impacts of sampling on the faunal communities and are looking for less invasive ways to investigate the vent ecosystems. In this perspective, imagery analysis plays a very important role. With this study, we test which factors can be quantitatively and accurately assessed based on imagery, through comparison with faunal sampling. Twelve instrumented chains were deployed on the Atlantic Eiffel Tower hydrothermal edifice and the corresponding study sites were subsequently sampled. Discrete, quantitative samples were compared to the imagery recorded during the experiment. An observer-effect was tested, by comparing imagery data gathered by different scientists. Most factors based on image analyses concerning Bathymodiolus azoricus mussels were shown to be valid representations of the corresponding samples. Additional ecological assets, based exclusively on imagery, were included. Copyright © 2012 Elsevier Ltd. All rights reserved.

A preliminary study of Mars rover/sample return missions

NASA Technical Reports Server (NTRS)

1987-01-01

The Solar System Exploration Committee (SSEC) of the NASA Advisory Council recommends that a Mars Sample Return mission be undertaken before the year 2000. Comprehensive studies of a Mars Sample Return mission have been ongoing since 1984. The initial focus of these studies was an integrated mission concept with the surface rover and sample return vehicle elements delivered to Mars on a single launch and landed together. This approach, to be carried out as a unilateral U.S. initiative, is still a high priority goal in an Augmented Program of exploration, as the SSEC recommendation clearly states. With this background of a well-understood mission concept, NASA decided to focus its 1986 study effort on a potential opportunity not previously examined; namely, a Mars Rover/Sample Return (MRSR) mission which would involve a significant aspect of international cooperation. As envisioned, responsibility for the various mission operations and hardware elements would be divided in a logical manner with clearly defined and acceptable interfaces. The U.S. and its international partner would carry out separately launched but coordinated missions with the overall goal of accomplishing in situ science and returning several kilograms of surface samples from Mars. Important considerations for implementation of such a plan are minimum technology transfer, maximum sharing of scientific results, and independent credibility of each mission role. Under the guidance and oversight of a Mars Exploration Strategy Advisory Group organized by NASA, a study team was formed in the fall of 1986 to develop a preliminary definition of a flight-separable, cooperative mission. The selected concept assumes that the U.S. would undertake the rover mission with its sample collection operations and our international partner would return the samples to Earth. Although the inverse of these roles is also possible, this study report focuses on the rover functions of MRSR because rover operations have not been studied in as much detail as the sample return functions of the mission.

A Mixed Methods Sampling Methodology for a Multisite Case Study

ERIC Educational Resources Information Center

Sharp, Julia L.; Mobley, Catherine; Hammond, Cathy; Withington, Cairen; Drew, Sam; Stringfield, Sam; Stipanovic, Natalie

2012-01-01

The flexibility of mixed methods research strategies makes such approaches especially suitable for multisite case studies. Yet the utilization of mixed methods to select sites for these studies is rarely reported. The authors describe their pragmatic mixed methods approach to select a sample for their multisite mixed methods case study of a…

Note: long-range scanning tunneling microscope for the study of nanostructures on insulating substrates.

PubMed

Molina-Mendoza, Aday J; Rodrigo, José G; Island, Joshua; Burzuri, Enrique; Rubio-Bollinger, Gabino; van der Zant, Herre S J; Agraït, Nicolás

2014-02-01

The scanning tunneling microscope (STM) is a powerful tool for studying the electronic properties at the atomic level, however, it is of relatively small scanning range and the fact that it can only operate on conducting samples prevents its application to study heterogeneous samples consisting of conducting and insulating regions. Here we present a long-range scanning tunneling microscope capable of detecting conducting micro and nanostructures on insulating substrates using a technique based on the capacitance between the tip and the sample and performing STM studies.

Using a monitoring and evaluation framework to improve study efficiency and quality during a prospective cohort study in infants receiving rotavirus vaccination in El Alto, Bolivia: the Infant Nutrition, Inflammation, and Diarrheal Illness (NIDI) study.

PubMed

Aceituno, Anna M; Stanhope, Kaitlyn K; Rebolledo, Paulina A; Burke, Rachel M; Revollo, Rita; Iñiguez, Volga; Suchdev, Parminder S; Leon, Juan S

2017-11-28

Implementing rigorous epidemiologic studies in low-resource settings involves challenges in participant recruitment and follow-up (e.g., mobile populations, distrust), biological sample collection (e.g., cold-chain, laboratory equipment scarcity) and data collection (e.g., literacy, staff training, and infrastructure). This article describes the use of a monitoring and evaluation (M&E) framework to improve study efficiency and quality during participant engagement, and biological sample and data collection in a longitudinal cohort study of Bolivian infants. The study occurred between 2013 and 2015 in El Alto, Bolivia, a high-altitude, urban, low-resource community. The study's M&E framework included indicators for participant engagement (e.g., recruitment, retention, safety), biological sample (e.g., stool and blood), and data (e.g., anthropometry, questionnaires) collection and quality. Monitoring indicators were measured regularly throughout the study and used for course correction, communication, and staff retraining. Participant engagement indicators suggested that enrollment objectives were met (461 infants), but 15% loss-to-follow-up resulted in only 364 infants completing the study. Over the course of the study, there were four study-related adverse events (minor swelling and bruising related to a blood draw) and five severe adverse events (infant deaths) not related to study participation. Biological sample indicators demonstrated two blood samples collected from 95% (333 of 350 required) infants and stool collected for 61% of reported infant diarrhea episodes. Anthropometry data quality indicators were extremely high (median SDs for weight-for-length, length-for-age and weight-for-age z-scores 1.01, 0.98, and 1.03, respectively), likely due to extensive training, standardization, and monitoring efforts. Conducting human subjects research studies in low-resource settings often presents unique logistical difficulties, and collecting high-quality data is often a challenge. Investing in comprehensive M&E is important to improve participant recruitment, retention and safety, and sample and data quality. The M&E framework from this study can be applied to other longitudinal studies.

Pharmaceutical compounds in shallow groundwater in non-agricultural areas of Minnesota: study design, methods, and data, 2013

USGS Publications Warehouse

Elliott, Sarah M.; Erickson, Melinda L.

2014-01-01

The U.S. Geological Survey, in cooperation with the Minnesota Pollution Control Agency, completed a study on the occurrence of pharmaceutical compounds and other contaminants of emerging concern in shallow groundwater in non-agricultural areas of Minnesota during 2013. This report describes the study design and methods for the study on the occurrence of pharmaceuticals and other contaminants of emerging concern, and presents the data collected on pharmaceutical compounds. Samples were analyzed by the U.S. Geological Survey National Water Quality Laboratory for 110 pharmaceutical compounds using research method 9017. Samples from 21 of 45 wells had detectable concentrations of at least one of the 110 compounds analyzed. One sample contained detectable concentrations of nine compounds, which was the most detected in a single sample. Fewer than five compounds were detected in most samples. Among all samples, 27 of the 110 compounds were detected in groundwater from at least one well. Desmethyldiltiazem and nicotine were the most frequently detected compounds, each detected in 5 of 46 environmental samples (one well was sampled twice so a total of 46 environmental samples were collected from 45 wells). Caffeine had the highest detectable concentration of all the compounds at 2,060 nanograms per liter.

Analysis of the Touch-And-Go Surface Sampling Concept for Comet Sample Return Missions

NASA Technical Reports Server (NTRS)

Mandic, Milan; Acikmese, Behcet; Bayard, David S.; Blackmore, Lars

2012-01-01

This paper studies the Touch-and-Go (TAG) concept for enabling a spacecraft to take a sample from the surface of a small primitive body, such as an asteroid or comet. The idea behind the TAG concept is to let the spacecraft descend to the surface, make contact with the surface for several seconds, and then ascend to a safe location. Sampling would be accomplished by an end-effector that is active during the few seconds of surface contact. The TAG event is one of the most critical events in a primitive body sample-return mission. The purpose of this study is to evaluate the dynamic behavior of a representative spacecraft during the TAG event, i.e., immediately prior, during, and after surface contact of the sampler. The study evaluates the sample-collection performance of the proposed sampling end-effector, in this case a brushwheel sampler, while acquiring material from the surface during the contact. A main result of the study is a guidance and control (G&C) validation of the overall TAG concept, in addition to specific contributions to demonstrating the effectiveness of using nonlinear clutch mechanisms in the sampling arm joints, and increasing the length of the sampling arms to improve robustness.

Randomised prospective study compares efficacy of five different stomach tubes for rumen fluid sampling in dairy cows.

PubMed

Steiner, S; Neidl, A; Linhart, N; Tichy, A; Gasteiner, J; Gallob, K; Baumgartner, W; Wittek, T

2015-01-10

The objective of the study was to compare the performance of five types of stomach tubes for rumen fluid sampling. Rumen fluid was sampled in rumen fistulated cows assigned to a 5×5 Latin square study design. The pH values of samples taken by stomach tubes and via fistulas were measured; the results were compared with indwelling sensor measurements. The practicability of the stomach tubes for regular use was tested in the field. Rumen fluid samples were obtained rapidly. Volumes for transfaunation could be obtained. The pH-values of samples taken with the four out of the five tubes (Dirksen, Geishauser, tube 4 and a simple water hose used with a gag) did not show significant differences to samples taken via rumen fistulas. Mean differences ranged between -0.02 and +0.09. Samples taken with tube 4 and the water hose showed also no significant differences to pH-sensor measurements. This study demonstrates that stomach tubes are suitable for rumen fluid sampling. Tube 4 seems to be the best probe for work in the field. It was well tolerated by the animals, saliva contamination is negligible. We, therefore, conclude that the evaluation of rumen acid base status in the field is possible. British Veterinary Association.

If I Could in a Small Way Help”: Motivations for and Beliefs about Sample Donation for Genetic Research

PubMed Central

Michie, Marsha; Henderson, Gail; Garrett, Joanne; Corbie-Smith, Giselle

2012-01-01

Human genome research depends upon participants who donate genetic samples, but few studies have explored in depth the motivations of genetic research donors. This mixed methods study examines telephone interviews with 752 sample donors in a U.S. genetic epidemiology study investigating colorectal cancer. Quantitative and qualitative results indicate that most participants wanted to help society, and that many also wanted information about their own health, even though such information was not promised. Qualitative analysis reveals that donors believed their samples contributed to a scientific “common good”; imagined samples as information rather than tissues; and often blurred distinctions between research and diagnostic testing of samples. Differences between African American and White perspectives were distinct from educational and other possible explanatory factors. PMID:21680977

In situ study of live specimens in an environmental scanning electron microscope.

PubMed

Tihlaříková, Eva; Neděla, Vilém; Shiojiri, Makoto

2013-08-01

In this paper we introduce new methodology for the observation of living biological samples in an environmental scanning electron microscope (ESEM). The methodology is based on an unconventional initiation procedure for ESEM chamber pumping, free from purge-flood cycles, and on the ability to control thermodynamic processes close to the sample. The gradual and gentle change of the working environment from air to water vapor enables the study of not only living samples in dynamic in situ experiments and their manifestation of life (sample walking) but also its experimentally stimulated physiological reactions. Moreover, Monte Carlo simulations of primary electron beam energy losses in a water layer on the sample surface were studied; consequently, the influence of the water thickness on radiation, temperature, or chemical damage of the sample was considered.

Epidemiology of Salmonella sp. in California cull dairy cattle: prevalence of fecal shedding and diagnostic accuracy of pooled enriched broth culture of fecal samples.

PubMed

Abu Aboud, Omran A; Adaska, John M; Williams, Deniece R; Rossitto, Paul V; Champagne, John D; Lehenbauer, Terry W; Atwill, Robert; Li, Xunde; Aly, Sharif S

2016-01-01

The primary objective of this cross-sectional study was to estimate the crude, seasonal and cull-reason stratified prevalence of Salmonella fecal shedding in cull dairy cattle on seven California dairies. A secondary objective was to estimate and compare the relative sensitivity (Se) and specificity (Sp) for pools of 5 and 10 enriched broth cultures of fecal samples for Salmonella sp. detection. Seven dairy farms located in the San Joaquin Valley of California were identified and enrolled in the study as a convenience sample. Cull cows were identified for fecal sampling once during each season between 2014 and 2015, specifically during spring, summer, fall, and winter, and 10 cows were randomly selected for fecal sampling at the day of their sale. In addition, study personnel completed a survey based on responses of the herd manager to questions related to the previous four month's herd management. Fecal samples were frozen until testing for Salmonella. After overnight enrichment in liquid broth, pools of enrichment broth (EBP) were created for 5 and 10 samples. All individual and pooled broths were cultured on selective media with putative Salmonella colonies confirmed by biochemical testing before being serogrouped and serotyped. A total of 249 cull cows were enrolled into the study and their fecal samples tested for Salmonella. The survey-weighted period prevalence of fecal shedding of all Salmonella sp. in the cull cow samples across all study herds and the entire study period was 3.42% (N = 249; SE 1.07). The within herd prevalence of Salmonella shed in feces did not differ over the four study seasons (P = 0.074). The Se of culture of EBP of five samples was 62.5% (SE = 17.12), which was not statistically different from the Se of culture of EBP of 10 (37.5%, SE = 17.12, P = 0.48). The Sp of culture of EBP of five samples was 95.24% (SE = 3.29) and for pools of 10 samples was 100.00% (SE = 0). There was no statistical difference between the culture relative specificities of EBP of 5 and 10 (P > 0.99). Our study showed a numerically higher prevalence of Salmonella shedding in the summer, although the results were not significant, most likely due to a lack of power from the small sample size. A higher prevalence in summer months may be related to heat stress. To detect Salmonella, investigators may expect a 62.5% sensitivity for culture of EBP of five, relative to individual fecal sample enrichment and culture. In contrast, culture of EBP of 10 samples resulted in a numerically lower Se. Culture of EBP of size 5 or 10 samples, given similar prevalence and limit of detection, can be expected to yield specificities of 95 and 100%, respectively.

Epidemiology of Salmonella sp. in California cull dairy cattle: prevalence of fecal shedding and diagnostic accuracy of pooled enriched broth culture of fecal samples

PubMed Central

Abu Aboud, Omran A.; Adaska, John M.; Williams, Deniece R.; Rossitto, Paul V.; Champagne, John D.; Lehenbauer, Terry W.; Atwill, Robert; Li, Xunde

2016-01-01

Background The primary objective of this cross-sectional study was to estimate the crude, seasonal and cull-reason stratified prevalence of Salmonella fecal shedding in cull dairy cattle on seven California dairies. A secondary objective was to estimate and compare the relative sensitivity (Se) and specificity (Sp) for pools of 5 and 10 enriched broth cultures of fecal samples for Salmonella sp. detection. Methods Seven dairy farms located in the San Joaquin Valley of California were identified and enrolled in the study as a convenience sample. Cull cows were identified for fecal sampling once during each season between 2014 and 2015, specifically during spring, summer, fall, and winter, and 10 cows were randomly selected for fecal sampling at the day of their sale. In addition, study personnel completed a survey based on responses of the herd manager to questions related to the previous four month’s herd management. Fecal samples were frozen until testing for Salmonella. After overnight enrichment in liquid broth, pools of enrichment broth (EBP) were created for 5 and 10 samples. All individual and pooled broths were cultured on selective media with putative Salmonella colonies confirmed by biochemical testing before being serogrouped and serotyped. Results A total of 249 cull cows were enrolled into the study and their fecal samples tested for Salmonella. The survey-weighted period prevalence of fecal shedding of all Salmonella sp. in the cull cow samples across all study herds and the entire study period was 3.42% (N = 249; SE 1.07). The within herd prevalence of Salmonella shed in feces did not differ over the four study seasons (P = 0.074). The Se of culture of EBP of five samples was 62.5% (SE = 17.12), which was not statistically different from the Se of culture of EBP of 10 (37.5%, SE = 17.12, P = 0.48). The Sp of culture of EBP of five samples was 95.24% (SE = 3.29) and for pools of 10 samples was 100.00% (SE = 0). There was no statistical difference between the culture relative specificities of EBP of 5 and 10 (P > 0.99). Discussion Our study showed a numerically higher prevalence of Salmonella shedding in the summer, although the results were not significant, most likely due to a lack of power from the small sample size. A higher prevalence in summer months may be related to heat stress. To detect Salmonella, investigators may expect a 62.5% sensitivity for culture of EBP of five, relative to individual fecal sample enrichment and culture. In contrast, culture of EBP of 10 samples resulted in a numerically lower Se. Culture of EBP of size 5 or 10 samples, given similar prevalence and limit of detection, can be expected to yield specificities of 95 and 100%, respectively. PMID:27635350

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

PubMed

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

2008-01-01

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

Questa baseline and pre-mining ground-water quality investigation. 2. Low-flow (2001) and snowmelt (2002) synoptic/tracer water chemistry for the Red River, New Mexico

USGS Publications Warehouse

McCleskey, R. Blaine; Nordstrom, D. Kirk; Steiger, Judy I.; Kimball, Briant A.; Verplanck, Philip L.

2003-01-01

Water analyses are reported for 259 samples collected from the Red River, New Mexico, and its tributaries during low-flow(2001) and spring snowmelt (2002) tracer studies. Water samples were collected along a 20-kilometer reach of the Red River beginning just east of the town of Red River and ending at the U.S. Geological Survey streamflow-gaging station located east of Questa, New Mexico. The study area was divided into three sections where separate injections and synoptic sampling events were performed during the low-flow tracer study. During the spring snowmelt tracer study, three tracer injections and synoptic sampling events were performed bracketing the areas with the greatest metal loading into the Red River as determined from the low-flow tracer study. The lowflow tracer synoptic sampling events were August 17, 20, and 24, 2001. The synoptic sampling events for the spring snowmelt tracer were March 30, 31, and April 1, 2002. Stream and large inflow water samples were sampled using equal-width and depth-integrated sampling methods and composited into half-gallon bottles. Grab water samples were collected from smaller inflows. Stream temperatures were measured at the time of sample collection. Samples were transported to a nearby central processing location where pH and specific conductance were measured and the samples processed for chemical analyses. Cations, trace metals, iron redox species, and fluoride were analyzed at the U.S. Geological Survey laboratory in Boulder, Colorado. Cations and trace metal concentrations were determined using inductively coupled plasma-optical emission spectrometry and graphite furnace atomic absorption spectrometry. Arsenic concentrations were determined using hydride generation atomic absorption spectrometry, iron redox species were measured using ultraviolet-visible spectrometry, and fluoride concentrations were determined using an ion-selective electrode. Alkalinity was measured by automated titration, and sulfate, chloride, and bromide were analyzed by ion chromatography at the U.S. Geological Survey laboratory in Salt Lake City, Utah.

COMPARISON OF SAMPLING TECHNIQUES USED IN STUDYING LEPIDOPTERA POPULATION DYNAMICS

EPA Science Inventory

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

Feasibility of using subject-collected dust samples in epidemiologic and clinical studies of indoor allergens.

PubMed

Arbes, Samuel J; Sever, Michelle; Vaughn, Ben; Mehta, Jigna; Lynch, Jeffrey T; Mitchell, Herman; Hoppin, Jane A; Spencer, Harvey L; Sandler, Dale P; Zeldin, Darryl C

2005-06-01

Studies of indoor allergen exposures are often limited by the cost and logistics of sending technicians to homes to collect dust. In this study we evaluated the feasibility of having subjects collect their own dust samples. The objectives were to compare allergen concentrations between subject- and technician-collected samples and to examine the sample return rate. Using a dust collection device and written instructions provided to them by mail, 102 subjects collected a combined dust sample from a bed and bedroom floor. Later the same day, a technician collected a side-by-side sample. Dust samples were weighed and analyzed for the cat allergen Fel d 1 and the dust mite allergen Der p 1. Fifty additional subjects who were enrolled by telephone were mailed dust collection packages and asked to return a dust sample and questionnaire by mail. A technician did not visit their homes. Correlations between subject- and technician-collected samples were strong for concentrations of Fel d 1 (r = 0.88) and Der p 1 (r = 0.87). With allergen concentrations dichotomized at lower limits of detection and clinically relevant thresholds, agreements between methodologies ranged from 91 to 98%. Although dust weights were correlated (r = 0.48, p < 0.001), subjects collected lighter samples. Among the group of 50 subjects, 46 returned a dust sample and completed questionnaire. The median number of days to receive a sample was 15. With some limitations, subject-collected dust sampling appears to be a valid and practical option for epidemiologic and clinical studies that report allergen concentration as a measure of exposure.

Genomic regions associated with bovine milk fatty acids in both summer and winter milk samples

PubMed Central

2012-01-01

Background In this study we perform a genome-wide association study (GWAS) for bovine milk fatty acids from summer milk samples. This study replicates a previous study where we performed a GWAS for bovine milk fatty acids based on winter milk samples from the same population. Fatty acids from summer and winter milk are genetically similar traits and we therefore compare the regions detected in summer milk to the regions previously detected in winter milk GWAS to discover regions that explain genetic variation in both summer and winter milk. Results The GWAS of summer milk samples resulted in 51 regions associated with one or more milk fatty acids. Results are in agreement with most associations that were previously detected in a GWAS of fatty acids from winter milk samples, including eight ‘new’ regions that were not considered in the individual studies. The high correlation between the –log10(P-values) and effects of SNPs that were found significant in both GWAS imply that the effects of the SNPs were similar on winter and summer milk fatty acids. Conclusions The GWAS of fatty acids based on summer milk samples was in agreement with most of the associations detected in the GWAS of fatty acids based on winter milk samples. Associations that were in agreement between both GWAS are more likely to be involved in fatty acid synthesis compared to regions detected in only one GWAS and are therefore worthwhile to pursue in fine-mapping studies. PMID:23107417

Microbial and Antibiotic Susceptibility Profile among Clinical Samples of Patients with Acute Leukemia.

PubMed

Abdollahi, Alireza; Hakimi, Faezeh; Doomanlou, Mahsa; Azadegan, Azadeh

2016-04-01

Preventing and starting early treatment of infections in patients whose immunity system is weak due to malignancies like leukemia can reduce mortality. This study aimed to determine microbial and antibiotic resistance patterns in clinical samples of patients with acute leukemia to start early treatment before the results of clinical tests are known. In this cross-sectional study, the clinical samples of all patients hospitalized with the diagnosis of acute leukemia were cultured and their antibiogram was evaluated. Then, the data were analyzed by SPSS 18 based on the objectives of the study. Of a total of 2,366 samples, 18.95% were reported to be positive blood samples, 22.96% were reported to be urine samples and 36% wound samples. E. coli was the most common bacteria isolated from the blood and urine cultures (34% in blood, 32% in urine culture) while Staphylococcus Aureus was the most common in the wound culture (35%). The highest level of sensitivity in the organisms with positive blood culture was to Ciprofloxacin, while in positive urine and wound culture was to Imipenem. The highest resistance in blood, urine and wound culture was to Cotrimoxazole. According to results obtained from this study, it is necessary to conduct appropriate studies on this issue in specific conditions in our country. The findings of this study can be used in clinics for more accurate diagnosis, more effective treatment before the results of clinical tests are known and also for prevention of infection in cancer patients.

Local versus field scale soil heterogeneity characterization - a challenge for representative sampling in pollution studies

NASA Astrophysics Data System (ADS)

Kardanpour, Z.; Jacobsen, O. S.; Esbensen, K. H.

2015-06-01

This study is a contribution to development of a heterogeneity characterisation facility for "next generation" sampling aimed at more realistic and controllable pesticide variability in laboratory pots in experimental environmental contaminant assessment. The role of soil heterogeneity on quantification of a set of exemplar parameters, organic matter, loss on ignition (LOI), biomass, soil microbiology, MCPA sorption and mineralization is described, including a brief background on how heterogeneity affects sampling/monitoring procedures in environmental pollutant studies. The Theory of Sampling (TOS) and variographic analysis has been applied to develop a fit-for-purpose heterogeneity characterization approach. All parameters were assessed in large-scale profile (1-100 m) vs. small-scale (0.1-1 m) replication sampling pattern. Variographic profiles of experimental analytical results concludes that it is essential to sample at locations with less than a 2.5 m distance interval to benefit from spatial auto-correlation and thereby avoid unnecessary, inflated compositional variation in experimental pots; this range is an inherent characteristic of the soil heterogeneity and will differ among soils types. This study has a significant carrying-over potential for related research areas e.g. soil science, contamination studies, and environmental monitoring and environmental chemistry.

Time Clustered Sampling Can Inflate the Inferred Substitution Rate in Foot-And-Mouth Disease Virus Analyses.

PubMed

Pedersen, Casper-Emil T; Frandsen, Peter; Wekesa, Sabenzia N; Heller, Rasmus; Sangula, Abraham K; Wadsworth, Jemma; Knowles, Nick J; Muwanika, Vincent B; Siegismund, Hans R

2015-01-01

With the emergence of analytical software for the inference of viral evolution, a number of studies have focused on estimating important parameters such as the substitution rate and the time to the most recent common ancestor (tMRCA) for rapidly evolving viruses. Coupled with an increasing abundance of sequence data sampled under widely different schemes, an effort to keep results consistent and comparable is needed. This study emphasizes commonly disregarded problems in the inference of evolutionary rates in viral sequence data when sampling is unevenly distributed on a temporal scale through a study of the foot-and-mouth (FMD) disease virus serotypes SAT 1 and SAT 2. Our study shows that clustered temporal sampling in phylogenetic analyses of FMD viruses will strongly bias the inferences of substitution rates and tMRCA because the inferred rates in such data sets reflect a rate closer to the mutation rate rather than the substitution rate. Estimating evolutionary parameters from viral sequences should be performed with due consideration of the differences in short-term and longer-term evolutionary processes occurring within sets of temporally sampled viruses, and studies should carefully consider how samples are combined.

Circulating tumoral cells lack circadian-rhythm in hospitalized metastasic breast cancer patients.

PubMed

García-Sáenz, José Angel; Martín, Miguel; Maestro, Marisa; Vidaurreta, Marta; Veganzones, Silvia; Villalobos, Laura; Rodríguez-Lajusticia, Laura; Rafael, Sara; Sanz-Casla, María Teresa; Casado, Antonio; Sastre, Javier; Arroyo, Manuel; Díaz-Rubio, Eduardo

2006-11-01

The relationship between breast cancer and circadian rhythm variation has been extensively studied. Increased breast tumorigenesis has been reported in melatonin-suppressed experimental models and in observational studies. Circulating Tumor Cells (CTC) circadian- rhythm may optimize the timing of therapies. This is a prospective experimental study to ascertain the day-time and night-time CTC levels in hospitalized metastasic breast cancer (MBC) patients. CTC are isolated and enumerated from a 08:00 AM and 08:00 PM blood collections. 23 MBC and 23 healthy volunteers entered the study. 69 samples were collected (23 samples at 08:00 AM and 23 samples at 08:00 PM from MBC; 23 samples from healthy volunteers). Results from two patients were rejected due to sample processing errors. No CTC were isolated from healthy-volunteers. No-differences between daytime and night-time CTC were observed. Therefore, we could not ascertain CTC circadian-rhythm in hospitalized metastasic breast cancer patients.

Depth-Resolved Cathodoluminescence Study of Annealed Silicon Implanted Gallium Arsenide.

DTIC Science & Technology

1982-12-01

samples were Cr doped semi-insulat- ing GaAs crystals grown using the horizontal Bridgman method. Nine samples were prepared for this study, four were...function of depth. Cathodoluminescence was the excitation method. The crystals studied were grown using the horizontal Bridgman method. Four samples were...achieved by taking spectral data and successively chemically etching the surface of the crystal in 250 R steps. No new peaks were observed in the

Biomarker-Based Prediction Models for Response to Treatment in Systemic Sclerosis-Related Interstitial Lung Disease

DTIC Science & Technology

2017-10-01

in the baseline samples of the Scleroderma Lung Study II (SLS II). We are currently analyzing whether these serum proteins have predictive...In this project, we use the valuable samples collected in the Scleroderma Lung Study II (SLSII) clinical trial and the observational cohort, GENISOS...determine key serum protein levels and transcript signatures in whole blood and skin samples collected in the SLSII study . The identified candidate

Rare-Earth Oxide (Yb2O3) Selective Emitter Fabrication and Evaluation

NASA Technical Reports Server (NTRS)

Jennette, Bryan; Gregory, Don A.; Herren, Kenneth; Tucker, Dennis; Smith, W. Scott (Technical Monitor)

2001-01-01

This investigation involved the fabrication and evaluation of rare-earth oxide selective emitters. The first goal of this study was to successfully fabricate the selective emitter samples using paper and ceramic materials processing techniques. The resulting microstructure was also analyzed using a Scanning Electron Microscope. All selective emitter samples fabricated for this study were made with ytterbium oxide (Yb2O3). The second goal of this study involved the measurement of the spectral emission and the radiated power of all the selective emitter samples. The final goal of this study involved the direct comparison of the radiated power emitted by the selective emitter samples to that of a standard blackbody at the same temperature and within the same wavelength range.

Use of warrants for breath test refusal : case studies

DOT National Transportation Integrated Search

2007-10-01

This study investigated the use of warrants to obtain blood samples from drivers arrested for alcohol-impaired driving and who refuse to provide breath samples when requested to do so by law enforcement officers. Case studies were conducted in four S...

NHEXAS PHASE I ARIZONA STUDY--LIST OF STANDARD OPERATING PROCEDURES

EPA Science Inventory

This document lists available protocols and SOPs for the NHEXAS Phase I Arizona study. It identifies protocols and SOPs for the following study components: (1) Sample collection and field operations, (2) Sample analysis, (3) General laboratory procedures, (4) Quality Assurance, (...

Replicating studies in which samples of participants respond to samples of stimuli.

PubMed

Westfall, Jacob; Judd, Charles M; Kenny, David A

2015-05-01

In a direct replication, the typical goal is to reproduce a prior experimental result with a new but comparable sample of participants in a high-powered replication study. Often in psychology, the research to be replicated involves a sample of participants responding to a sample of stimuli. In replicating such studies, we argue that the same criteria should be used in sampling stimuli as are used in sampling participants. Namely, a new but comparable sample of stimuli should be used to ensure that the original results are not due to idiosyncrasies of the original stimulus sample, and the stimulus sample must often be enlarged to ensure high statistical power. In support of the latter point, we discuss the fact that in experiments involving samples of stimuli, statistical power typically does not approach 1 as the number of participants goes to infinity. As an example of the importance of sampling new stimuli, we discuss the bygone literature on the risky shift phenomenon, which was almost entirely based on a single stimulus sample that was later discovered to be highly unrepresentative. We discuss the use of both resampled and expanded stimulus sets, that is, stimulus samples that include the original stimuli plus new stimuli. © The Author(s) 2015.

Melting behavior and phase relations of lunar samples. [Apollo 12 rock samples

NASA Technical Reports Server (NTRS)

Hays, J. F.

1975-01-01

Cooling rate studies of 12002 were conducted and the results interpreted in terms of the crystallization history of this rock and certain other picritic Apollo 12 samples. Calculations of liquid densities and viscosities during crystallization, crystal settling velocities, and heat loss by the parent rock body are discussed, as are petrographic studies of other Apollo 12 samples. The process of magmatic differentiation that must have accompanied the early melting and chemical fractionation of the moon's outer layers was investigated. The source of regions of both high- and low-titanium mare basalts were also studied.

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR FIELD COLLECTION AND POST-FIELD SAMPLE HANDLING OF INDOOR FLOOR DUST SAMPLES (UA-F-7.1)

EPA Science Inventory

The purpose of this SOP is to establish a uniform procedure for the collection of indoor floor dust samples in the field. This procedure was followed to ensure consistent data retrieval of dust samples during the Arizona NHEXAS project and the Border study. Keywords: field; vacu...

A Comparison of Two Sampling Strategies to Assess Discomycete Diversity in Wet Tropical Forests

Treesearch

SHARON A. CANTRELL

2004-01-01

Most of the fungal diversity studies that have used a systematic collecting scheme have not included the discomycetes, so optimal sampling methods are not available for this group. In this study, I tested two sampling methods at each sites in the Caribbean National Forest, Puerto Rico and Ebano Verde Reserve, Dominican Republic. For a plot-based sampling method, 10 ×...

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR ANALYSIS OF SOIL OR HOUSE DUST SAMPLES USING CHLORPYRIFOS ELISA SAMPLES (BCO-L-1.0)

EPA Science Inventory

This abstract is included for completeness of documentation, but this SOP was not used in the study.

The purpose of this SOP is to describe the procedures for analyzing both Stage II and Stage III soil and vacuum-cleaner collected house dust samples, and Stage III air samples u...

Sample size calculations for case-control studies

Cancer.gov

This R package can be used to calculate the required samples size for unconditional multivariate analyses of unmatched case-control studies. The sample sizes are for a scalar exposure effect, such as binary, ordinal or continuous exposures. The sample sizes can also be computed for scalar interaction effects. The analyses account for the effects of potential confounder variables that are also included in the multivariate logistic model.

Sampling methods for the study of pneumococcal carriage: a systematic review.

PubMed

Gladstone, R A; Jefferies, J M; Faust, S N; Clarke, S C

2012-11-06

Streptococcus pneumoniae is an important pathogen worldwide. Accurate sampling of S. pneumoniae carriage is central to surveillance studies before and following conjugate vaccination programmes to combat pneumococcal disease. Any bias introduced during sampling will affect downstream recovery and typing. Many variables exist for the method of collection and initial processing, which can make inter-laboratory or international comparisons of data complex. In February 2003, a World Health Organisation working group published a standard method for the detection of pneumococcal carriage for vaccine trials to reduce or eliminate variability. We sought to describe the variables associated with the sampling of S. pneumoniae from collection to storage in the context of the methods recommended by the WHO and those used in pneumococcal carriage studies since its publication. A search of published literature in the online PubMed database was performed on the 1st June 2012, to identify published studies that collected pneumococcal carriage isolates, conducted after the publication of the WHO standard method. After undertaking a systematic analysis of the literature, we show that a number of differences in pneumococcal sampling protocol continue to exist between studies since the WHO publication. The majority of studies sample from the nasopharynx, but the choice of swab and swab transport media is more variable between studies. At present there is insufficient experimental data that supports the optimal sensitivity of any standard method. This may have contributed to incomplete adoption of the primary stages of the WHO detection protocol, alongside pragmatic or logistical issues associated with study design. Consequently studies may not provide a true estimate of pneumococcal carriage. Optimal sampling of carriage could lead to improvements in downstream analysis and the evaluation of pneumococcal vaccine impact and extrapolation to pneumococcal disease control therefore further in depth comparisons would be of value. Copyright © 2012 Elsevier Ltd. All rights reserved.

Detection of Genital HPV Infection Using Urine Samples: a Population Based Study in India.

PubMed

Sabeena, Sasidharanpillai; Bhat, Parvati; Kamath, Veena; Mathew, Mary; Aswathyraj, Sushama; Devadiga, Santhosha; Prabhu, Suresha; Hindol, Maity; Chameetachal, Akhil; Krishnan, Anjana; Arunkumar, Govindakarnavar

2016-01-01

Cervical cancer is the second commonest cancer among Indian women and its association with human papilloma virus (HPV) is well established. This preventable cancer accounts for the maximum number of cancer related deaths among rural Indian women. Unlike in developed countries there are no organized cervical cancer screening programmes in India due to lack of resources and manpower. To detect genital HPV infection using urine samples among asymptomatic rural women in the age group of 18-65 years. The study area chosen was Perdoor village in Udupi Taluk, Karnataka State and all the women in the age group of 18-65 years formed the study cohort. A cross sectional study was conducted by house visits and 1,305 women were enrolled in the study. After taking written informed consent a data sheet was filled and early stream random urine samples were collected, transported to a laboratory at 4OC and aliquoted. Samples were tested using nested HPV PCR with PGMY09/11 and GP5+/6+ primers. Positive cases were genotyped by sequence analysis. Study participants included 1,134 sexually active and 171 unmarried women with a mean age at marriage of 22.1 (SD=3.9) years. Study area showed high female literacy rate of 86.6%. Five urine samples tested positive for HPV DNA (0.4%). We found very low genital HPV infection rate among women from monogamous community. This is the first major population based study carried out among asymptomatic rural women to detect genital HPV infectio from Karnataka using urine samples.

Analysis of intraosseous samples in endotoxemic shock--an experimental study in the anaesthetised pig.

PubMed

Strandberg, G; Larsson, A; Lipcsey, M; Berglund, L; Eriksson, M

2014-03-01

Intraosseous (IO) access is used in emergency situations to allow rapid initiation of treatment. IO access is also sometimes used for blood sampling, although data on accuracy of such sampling in critical illness are limited. There is also a potential risk that bone marrow fragments in IO samples may damage laboratory equipment. It is ethically questionable to perform a simultaneous comparison between IO and arterial/venous sampling in critically ill humans. We have, thus, studied the analytical performance of IO sampling in a porcine septic shock model using a cartridge-based analyser. Eight pigs with endotoxin-induced septic shock were sampled hourly for 6 h, and analysed for blood gases, acid base status, haemoglobin, glucose and lactate using point of care instruments. Samples were taken from three IO cannulae (tibia bilaterally, one with infusion, and humerus), one arterial and one venous. An interaction test was used to assess changes in agreement between methods over time. Bland–Altman plots were constructed to study bias between methods. There were, to a varying extent, differences between IO and arterial/venous levels for all studied variables, but agreement did not change significantly during the experiment. A general finding was a large dispersion of differences between methods. IO sample values should be treated with caution in this setting but may add useful information to the clinical picture. The tibia or humerus may be used for sampling. IO infusion decreases agreement, thus sampling during infusion should be avoided.

Sample handling for mass spectrometric proteomic investigations of human sera.

PubMed

West-Nielsen, Mikkel; Høgdall, Estrid V; Marchiori, Elena; Høgdall, Claus K; Schou, Christian; Heegaard, Niels H H

2005-08-15

Proteomic investigations of sera are potentially of value for diagnosis, prognosis, choice of therapy, and disease activity assessment by virtue of discovering new biomarkers and biomarker patterns. Much debate focuses on the biological relevance and the need for identification of such biomarkers while less effort has been invested in devising standard procedures for sample preparation and storage in relation to model building based on complex sets of mass spectrometric (MS) data. Thus, development of standardized methods for collection and storage of patient samples together with standards for transportation and handling of samples are needed. This requires knowledge about how sample processing affects MS-based proteome analyses and thereby how nonbiological biased classification errors are avoided. In this study, we characterize the effects of sample handling, including clotting conditions, storage temperature, storage time, and freeze/thaw cycles, on MS-based proteomics of human serum by using principal components analysis, support vector machine learning, and clustering methods based on genetic algorithms as class modeling and prediction methods. Using spiking to artificially create differentiable sample groups, this integrated approach yields data that--even when working with sample groups that differ more than may be expected in biological studies--clearly demonstrate the need for comparable sampling conditions for samples used for modeling and for the samples that are going into the test set group. Also, the study emphasizes the difference between class prediction and class comparison studies as well as the advantages and disadvantages of different modeling methods.

Evaluation of Skin Surface as an Alternative Source of Reference DNA Samples: A Pilot Study.

PubMed

Albujja, Mohammed H; Bin Dukhyil, Abdul Aziz; Chaudhary, Abdul Rauf; Kassab, Ahmed Ch; Refaat, Ahmed M; Babu, Saranya Ramesh; Okla, Mohammad K; Kumar, Sachil

2018-01-01

An acceptable area for collecting DNA reference sample is a part of the forensic DNA analysis development. The aim of this study was to evaluate skin surface cells (SSC) as an alternate source of reference DNA sample. From each volunteer (n = 10), six samples from skin surface areas (forearm and fingertips) and two traditional samples (blood and buccal cells) were collected. Genomic DNA was extracted and quantified then genotyped using standard techniques. The highest DNA concentration of SSC samples was collected using the tape/forearm method of collection (2.1 ng/μL). Cotton swabs moistened with ethanol yielded higher quantities of DNA than swabs moistened with salicylic acid, and it gave the highest percentage of full STR profiles (97%). This study supports the use of SSC as a noninvasive sampling technique and as a extremely useful source of DNA reference samples among certain cultures where the use of buccal swabs can be considered socially unacceptable. © 2017 American Academy of Forensic Sciences.

How Large Should a Statistical Sample Be?

ERIC Educational Resources Information Center

Menil, Violeta C.; Ye, Ruili

2012-01-01

This study serves as a teaching aid for teachers of introductory statistics. The aim of this study was limited to determining various sample sizes when estimating population proportion. Tables on sample sizes were generated using a C[superscript ++] program, which depends on population size, degree of precision or error level, and confidence…

NHEXAS PHASE I ARIZONA STUDY--METALS IN DERMAL WIPES ANALYTICAL RESULTS

EPA Science Inventory

The Metals in Dermal Wipes data set contains analytical results for measurements of up to 11 metals in 179 dermal wipe samples over 179 households. Each sample was collected from the primary respondent within each household during Stage III of the NHEXAS study. The sampling per...

Preschoolers' Mathematics Skills and Behavior: Analysis of a National Sample

ERIC Educational Resources Information Center

Dobbs-Oates, Jennifer; Robinson, Chanele

2012-01-01

This study investigated the association between children's mathematical skills and their behavior in the prekindergarten year in a national sample of children attending center-based child care. The sample consisted of approximately 5,400 preschoolers in center-based care from the Early Childhood Longitudinal Study--Birth Cohort. Children's math…

NHEXAS PHASE I ARIZONA STUDY--METALS IN URINE ANALYTICAL RESULTS

EPA Science Inventory

The Metals in Urine data set contains analytical results for measurements of up to 6 metals in 176 urine samples over 176 households. Each sample was collected from the primary respondent within each household during Stage III of the NHEXAS study. The sample consists of the fir...

CoSMoS and TwinPaW: initial report on two new German twin studies.

PubMed

Spinath, Frank M; Wolf, Heike

2006-12-01

After briefly recapitulating two earlier German twin studies (BiLSAT and GOSAT), we present two new German twin studies with a longitudinal perspective: CoSMoS and TwinPaW. The twin study on Cognitive ability, Self-reported Motivation and School performance (CoSMoS) aims to investigate predictors and influences of school performance in a genetically sensitive design, beginning with children in late elementary school. The Twin study on Personality And Wellbeing (TwinPaW) focuses on adult personality and its relation to physical health as well as health-related behavior in an adult sample of twins. Both studies are characterized by an effort to recruit new large twin samples through a novel recruitment procedure aimed at reducing self-selective sampling. In two German federal states, contact information on persons born on the same day and with the same name was retrieved from record sections. From the resulting pool of more than 36,000 addresses we contacted approximately 2000 parents of twins aged 9 and 10 for CoSMoS, as well as 2000 adult twin pairs for TwinPaW by telephone and mail. Personal contact by telephone proved to be more efficient with agreement rates of 63% in the children sample and 65% in the adult sample. In this article we briefly describe the rationale and the study aims of CoSMoS and TwinPaW as well as the characteristics of the sample we have recruited so far.

Sexual Abuse among Female High School Students in Istanbul, Turkey

ERIC Educational Resources Information Center

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

2006-01-01

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

Adapting Depression and Anxiety Questionnaire for Children into Turkish: Reliability and Validity Studies

ERIC Educational Resources Information Center

Ay, Ismail; Secer, Ismail; Simsek, Mustafa Kerim

2017-01-01

Purpose of this study is to adapt anxiety and depression questionnaire for children into Turkish culture and to analyze the psychometric characteristics of it on clinical and nonclinical samples separately. The study is a descriptive survey research. The study was conducted on two different sample groups, clinical and nonclinical. The clinical…

Is there gender bias in nursing research?

PubMed

Polit, Denise F; Beck, Cheryl Tatano

2008-10-01

Using data from a consecutive sample of 259 studies published in four leading nursing research journals in 2005-2006, we examined whether nurse researchers favor females as study participants. On average, 75.3% of study participants were female, and 38% of studies had all-female samples. The bias favoring female participants was statistically significant and persistent. The bias was observed regardless of funding source, methodological features, and other participant and researcher characteristics, with one exception: studies that had male investigators had more sex-balanced samples. When designing studies, nurse researchers need to pay close attention to who will benefit from their research and to whether they are leaving out a specific group about which there is a gap in knowledge. (c) 2008 Wiley Periodicals, Inc.

Ovarian hormones and binge eating: exploring associations in community samples

PubMed Central

Klump, K. L.; Keel, P. K.; Culbert, K. M.; Edler, C.

2010-01-01

Background Significant associations between changes in ovarian hormones and binge eating are present across the menstrual cycle in women with bulimia nervosa. However, no study has examined these relationships in a non-clinical sample, despite the need for these data for designing risk-factor studies. Method In study 1, we modified several continuous measures of binge eating and identified those that were most sensitive to menstrual-cycle fluctuations in a non-clinical sample of 10 women who completed measures for 35 days. In study 2, we explored associations between ovarian hormones and binge-eating scores in nine women who completed these same measures for 65 days and provided daily saliva samples for assays of estradiol and progesterone concentrations. Results In study 1, the Emotional Eating subscale of the Dutch Eating Behavior Questionnaire exhibited superior reliability and was most sensitive to predicted menstrual-cycle changes in binge eating (i.e. increased scores in the mid-luteal/premenstrual compared with follicular/ovulatory phases). In study 2, this scale showed predicted inverse associations with estradiol and positive associations with progesterone across the menstrual cycle that could not be accounted for by changes in negative affect. Conclusion Associations between ovarian hormones and binge eating are robust and present in clinical and non-clinical samples. Findings support the ability to examine the role of ovarian hormones as risk factors for binge eating in large-scale prospective studies and twin studies. PMID:18307829

Mass spectra features of biomass burning boiler and coal burning boiler emitted particles by single particle aerosol mass spectrometer.

PubMed

Xu, Jiao; Li, Mei; Shi, Guoliang; Wang, Haiting; Ma, Xian; Wu, Jianhui; Shi, Xurong; Feng, Yinchang

2017-11-15

In this study, single particle mass spectra signatures of both coal burning boiler and biomass burning boiler emitted particles were studied. Particle samples were suspended in clean Resuspension Chamber, and analyzed by ELPI and SPAMS simultaneously. The size distribution of BBB (biomass burning boiler sample) and CBB (coal burning boiler sample) are different, as BBB peaks at smaller size, and CBB peaks at larger size. Mass spectra signatures of two samples were studied by analyzing the average mass spectrum of each particle cluster extracted by ART-2a in different size ranges. In conclusion, BBB sample mostly consists of OC and EC containing particles, and a small fraction of K-rich particles in the size range of 0.2-0.5μm. In 0.5-1.0μm, BBB sample consists of EC, OC, K-rich and Al_Silicate containing particles; CBB sample consists of EC, ECOC containing particles, while Al_Silicate (including Al_Ca_Ti_Silicate, Al_Ti_Silicate, Al_Silicate) containing particles got higher fractions as size increase. The similarity of single particle mass spectrum signatures between two samples were studied by analyzing the dot product, results indicated that part of the single particle mass spectra of two samples in the same size range are similar, which bring challenge to the future source apportionment activity by using single particle aerosol mass spectrometer. Results of this study will provide physicochemical information of important sources which contribute to particle pollution, and will support source apportionment activities. Copyright © 2017. Published by Elsevier B.V.

Discrimination of non-explosive and explosive samples through nitrocellulose fingerprints obtained by capillary electrophoresis.

PubMed

Fernández de la Ossa, Ma Ángeles; Ortega-Ojeda, Fernando; García-Ruiz, Carmen

2013-08-09

This work is focused on a novel procedure to discriminate nitrocellulose-based samples with non-explosive and explosive properties. The nitrocellulose study has been scarcely approached in the literature due to its special polymeric properties such as its high molar mass and complex chemical and structural characteristics. These properties require the nitrocellulose analysis to be performed by using a few organic solvents and in consequence, they limit the number of adequate analytical techniques for its study. In terms of identification of pre-blast explosives, mass spectrometry is one of the most preferred technique because it allows to obtain structural information. However, it has never been used to analyze polymeric nitrocellulose. In this study, the differentiation of non-explosive and explosive samples through nitrocellulose fingerprints obtained by capillary electrophoresis was investigated. A batch of 30 different smokeless gunpowders and 23 different everyday products were pulverized, derivatized with a fluorescent agent and analyzed by capillary electrophoresis with laser-induced fluorescence detection. Since this methodology is specific to d-glucopyranose derivatives (cellulosic and related compounds), and paper samples could be easily found in explosion scenes, 11 different paper samples were also included in the study as potential interference samples. In order to discriminate among samples, multivariate analysis (principal component analysis and soft independent modeling of class analogy) was applied to the obtained electrophoretic profiles. To the best of our knowledge, this represents the first study that achieve a successful discrimination between non-explosive and explosive nitrocellulose-based samples, as well as potential cellulose interference samples, and posterior classification of unknown samples into their corresponding groups using CE-LIF and chemometric tools. Copyright © 2013 Elsevier B.V. All rights reserved.

Linking Associations of Rare Low-Abundance Species to Their Environments by Association Networks

DOE PAGES

Karpinets, Tatiana V.; Gopalakrishnan, Vancheswaran; Wargo, Jennifer; ...

2018-03-07

Studies of microbial communities by targeted sequencing of rRNA genes lead to recovering numerous rare low-abundance taxa with unknown biological roles. We propose to study associations of such rare organisms with their environments by a computational framework based on transformation of the data into qualitative variables. Namely, we analyze the sparse table of putative species or OTUs (operational taxonomic units) and samples generated in such studies, also known as an OTU table, by collecting statistics on co-occurrences of the species and on shared species richness across samples. Based on the statistics we built two association networks, of the rare putativemore » species and of the samples respectively, using a known computational technique, Association networks (Anets) developed for analysis of qualitative data. Clusters of samples and clusters of OTUs are then integrated and combined with metadata of the study to produce a map of associated putative species in their environments. We tested and validated the framework on two types of microbiomes, of human body sites and that of the Populus tree root systems. We show that in both studies the associations of OTUs can separate samples according to environmental or physiological characteristics of the studied systems.« less

Linking Associations of Rare Low-Abundance Species to Their Environments by Association Networks

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

Karpinets, Tatiana V.; Gopalakrishnan, Vancheswaran; Wargo, Jennifer

Studies of microbial communities by targeted sequencing of rRNA genes lead to recovering numerous rare low-abundance taxa with unknown biological roles. We propose to study associations of such rare organisms with their environments by a computational framework based on transformation of the data into qualitative variables. Namely, we analyze the sparse table of putative species or OTUs (operational taxonomic units) and samples generated in such studies, also known as an OTU table, by collecting statistics on co-occurrences of the species and on shared species richness across samples. Based on the statistics we built two association networks, of the rare putativemore » species and of the samples respectively, using a known computational technique, Association networks (Anets) developed for analysis of qualitative data. Clusters of samples and clusters of OTUs are then integrated and combined with metadata of the study to produce a map of associated putative species in their environments. We tested and validated the framework on two types of microbiomes, of human body sites and that of the Populus tree root systems. We show that in both studies the associations of OTUs can separate samples according to environmental or physiological characteristics of the studied systems.« less

Caution regarding the choice of standard deviations to guide sample size calculations in clinical trials.

PubMed

Chen, Henian; Zhang, Nanhua; Lu, Xiaosun; Chen, Sophie

2013-08-01

The method used to determine choice of standard deviation (SD) is inadequately reported in clinical trials. Underestimations of the population SD may result in underpowered clinical trials. This study demonstrates how using the wrong method to determine population SD can lead to inaccurate sample sizes and underpowered studies, and offers recommendations to maximize the likelihood of achieving adequate statistical power. We review the practice of reporting sample size and its effect on the power of trials published in major journals. Simulated clinical trials were used to compare the effects of different methods of determining SD on power and sample size calculations. Prior to 1996, sample size calculations were reported in just 1%-42% of clinical trials. This proportion increased from 38% to 54% after the initial Consolidated Standards of Reporting Trials (CONSORT) was published in 1996, and from 64% to 95% after the revised CONSORT was published in 2001. Nevertheless, underpowered clinical trials are still common. Our simulated data showed that all minimal and 25th-percentile SDs fell below 44 (the population SD), regardless of sample size (from 5 to 50). For sample sizes 5 and 50, the minimum sample SDs underestimated the population SD by 90.7% and 29.3%, respectively. If only one sample was available, there was less than 50% chance that the actual power equaled or exceeded the planned power of 80% for detecting a median effect size (Cohen's d = 0.5) when using the sample SD to calculate the sample size. The proportions of studies with actual power of at least 80% were about 95%, 90%, 85%, and 80% when we used the larger SD, 80% upper confidence limit (UCL) of SD, 70% UCL of SD, and 60% UCL of SD to calculate the sample size, respectively. When more than one sample was available, the weighted average SD resulted in about 50% of trials being underpowered; the proportion of trials with power of 80% increased from 90% to 100% when the 75th percentile and the maximum SD from 10 samples were used. Greater sample size is needed to achieve a higher proportion of studies having actual power of 80%. This study only addressed sample size calculation for continuous outcome variables. We recommend using the 60% UCL of SD, maximum SD, 80th-percentile SD, and 75th-percentile SD to calculate sample size when 1 or 2 samples, 3 samples, 4-5 samples, and more than 5 samples of data are available, respectively. Using the sample SD or average SD to calculate sample size should be avoided.

NHEXAS PHASE I MARYLAND STUDY--LIST OF AVAILABLE DOCUMENTS: PROTOCOLS AND SOPS

EPA Science Inventory

This document lists available protocols and SOPs for the NHEXAS Phase I Maryland study. It identifies protocols and SOPs for the following study components: (1) Sample collection and field operations, (2) Sample analysis and general laboratory procedures, (3) Data Analysis Proced...

Statistical inference for the additive hazards model under outcome-dependent sampling.

PubMed

Yu, Jichang; Liu, Yanyan; Sandler, Dale P; Zhou, Haibo

2015-09-01

Cost-effective study design and proper inference procedures for data from such designs are always of particular interests to study investigators. In this article, we propose a biased sampling scheme, an outcome-dependent sampling (ODS) design for survival data with right censoring under the additive hazards model. We develop a weighted pseudo-score estimator for the regression parameters for the proposed design and derive the asymptotic properties of the proposed estimator. We also provide some suggestions for using the proposed method by evaluating the relative efficiency of the proposed method against simple random sampling design and derive the optimal allocation of the subsamples for the proposed design. Simulation studies show that the proposed ODS design is more powerful than other existing designs and the proposed estimator is more efficient than other estimators. We apply our method to analyze a cancer study conducted at NIEHS, the Cancer Incidence and Mortality of Uranium Miners Study, to study the risk of radon exposure to cancer.

Statistical inference for the additive hazards model under outcome-dependent sampling

PubMed Central

Yu, Jichang; Liu, Yanyan; Sandler, Dale P.; Zhou, Haibo

2015-01-01

Cost-effective study design and proper inference procedures for data from such designs are always of particular interests to study investigators. In this article, we propose a biased sampling scheme, an outcome-dependent sampling (ODS) design for survival data with right censoring under the additive hazards model. We develop a weighted pseudo-score estimator for the regression parameters for the proposed design and derive the asymptotic properties of the proposed estimator. We also provide some suggestions for using the proposed method by evaluating the relative efficiency of the proposed method against simple random sampling design and derive the optimal allocation of the subsamples for the proposed design. Simulation studies show that the proposed ODS design is more powerful than other existing designs and the proposed estimator is more efficient than other estimators. We apply our method to analyze a cancer study conducted at NIEHS, the Cancer Incidence and Mortality of Uranium Miners Study, to study the risk of radon exposure to cancer. PMID:26379363

Conventional and Accelerated-Solvent Extractions of Green Tea (Camellia sinensis) for Metabolomics-based Chemometrics

PubMed Central

Kellogg, Joshua J.; Wallace, Emily D.; Graf, Tyler N.; Oberlies, Nicholas H.; Cech, Nadja B.

2018-01-01

Metabolomics has emerged as an important analytical technique for multiple applications. The value of information obtained from metabolomics analysis depends on the degree to which the entire metabolome is present and the reliability of sample treatment to ensure reproducibility across the study. The purpose of this study was to compare methods of preparing complex botanical extract samples prior to metabolomics profiling. Two extraction methodologies, accelerated solvent extraction and a conventional solvent maceration, were compared using commercial green tea [Camellia sinensis (L.) Kuntze (Theaceae)] products as a test case. The accelerated solvent protocol was first evaluated to ascertain critical factors influencing extraction using a D-optimal experimental design study. The accelerated solvent and conventional extraction methods yielded similar metabolite profiles for the green tea samples studied. The accelerated solvent extraction yielded higher total amounts of extracted catechins, was more reproducible, and required less active bench time to prepare the samples. This study demonstrates the effectiveness of accelerated solvent as an efficient methodology for metabolomics studies. PMID:28787673

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

PubMed

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

2013-12-01

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

Development study of the X-ray scattering properties of a group of optically polished flat samples

NASA Technical Reports Server (NTRS)

Froechtenigt, J. F.

1973-01-01

A group of twelve optically polished flat samples were used to study the scattering of X-rays. The X-ray beam reflected from the twelve optical flat samples was analyzed by means of a long vacuum system of special design for these tests. The scattering measurements were made at 8.34A and 0.92 deg angle of incidence. The results for ten of the samples are comparable, the two exceptions being the fire polished samples.

Corn blight review: Sampling model and ground data measurements program

NASA Technical Reports Server (NTRS)

Allen, R. D.

1972-01-01

The sampling plan involved the selection of the study area, determination of the flightline and segment sample design within the study area, and determination of a field sample design. Initial interview survey data consisting of crop species acreage and land use were collected. On all corn fields, additional information such as seed type, row direction, population, planting date, ect. were also collected. From this information, sample corn fields were selected to be observed through the growing season on a biweekly basis by county extension personnel.

Effect of Salivary pH on Color Stability of Different Flowable Composites - A Prospective In-vitro Study.

PubMed

Batra, Renu; Kataria, Pratik; Kapoor, Sonali

2016-10-01

Scientifically and clinically there has been lot of development in the field of aesthetic dentistry. However, there is limited or restricted information regarding the color stability of flowable composite materials. The aim of this study was to evaluate the spectrophotometric color stability of three different flowable composite materials with respect to three different pH of saliva. The study included 90 different samples. Thirty samples in each composite group; (Group A: G-aenial universal flo; Group B: Z 350 XT flowable; Group C: Esthet x flow). All samples from each group were immersed in distilled water for 24 hours. Total color difference (ΔE) was recorded for each sample. After this 10 samples from each group were respectively immersed in 6.5, 7 and 7.5 pH of artificial saliva. All samples were kept in dark room for seven days and then ΔE for each sample was recorded and was compared to previous recorded ΔE for the same sample. Maximum color change was seen irrespective of material in 6.5 pH of saliva. G-aenial universal flo showed least change irrespective of pH of saliva. Thus, the present study reveals that acidic pH level affects the coloration of composite resins by affecting the surface integrity and as reported in previous studies, various coloring agents in beverages and other dietary components assists the process due to absorption of these coloring substances into the resin matrix.

Successful Sampling Strategy Advances Laboratory Studies of NMR Logging in Unconsolidated Aquifers

NASA Astrophysics Data System (ADS)

Behroozmand, Ahmad A.; Knight, Rosemary; Müller-Petke, Mike; Auken, Esben; Barfod, Adrian A. S.; Ferré, Ty P. A.; Vilhelmsen, Troels N.; Johnson, Carole D.; Christiansen, Anders V.

2017-11-01

The nuclear magnetic resonance (NMR) technique has become popular in groundwater studies because it responds directly to the presence and mobility of water in a porous medium. There is a need to conduct laboratory experiments to aid in the development of NMR hydraulic conductivity models, as is typically done in the petroleum industry. However, the challenge has been obtaining high-quality laboratory samples from unconsolidated aquifers. At a study site in Denmark, we employed sonic drilling, which minimizes the disturbance of the surrounding material, and extracted twelve 7.6 cm diameter samples for laboratory measurements. We present a detailed comparison of the acquired laboratory and logging NMR data. The agreement observed between the laboratory and logging data suggests that the methodologies proposed in this study provide good conditions for studying NMR measurements of unconsolidated near-surface aquifers. Finally, we show how laboratory sample size and condition impact the NMR measurements.

Logistics and quality control for DNA sampling in large multicenter studies.

PubMed

Nederhand, R J; Droog, S; Kluft, C; Simoons, M L; de Maat, M P M

2003-05-01

To study associations between genetic variation and disease, large bio-banks need to be created in multicenter studies. Therefore, we studied the effects of storage time and temperature on DNA quality and quantity in a simulation experiment with storage up to 28 days frozen, at 4 degrees C and at room temperature. In the simulation experiment, the conditions did not influence the amount or quality of DNA to an unsatisfactory level. However, the amount of extracted DNA was decreased in frozen samples and in samples that were stored for > 7 days at room temperature. In a sample of patients from 24 countries of the EUROPA trial obtained by mail with transport times up to 1 month DNA yield and quality were adequate. From these results we conclude that transport of non-frozen blood by ordinary mail is usable and practical for DNA isolation for polymerase chain reaction in clinical and epidemiological studies.

Estimating effect of environmental contaminants on women's subfecundity for the MoBa study data with an outcome-dependent sampling scheme

PubMed Central

Ding, Jieli; Zhou, Haibo; Liu, Yanyan; Cai, Jianwen; Longnecker, Matthew P.

2014-01-01

Motivated by the need from our on-going environmental study in the Norwegian Mother and Child Cohort (MoBa) study, we consider an outcome-dependent sampling (ODS) scheme for failure-time data with censoring. Like the case-cohort design, the ODS design enriches the observed sample by selectively including certain failure subjects. We present an estimated maximum semiparametric empirical likelihood estimation (EMSELE) under the proportional hazards model framework. The asymptotic properties of the proposed estimator were derived. Simulation studies were conducted to evaluate the small-sample performance of our proposed method. Our analyses show that the proposed estimator and design is more efficient than the current default approach and other competing approaches. Applying the proposed approach with the data set from the MoBa study, we found a significant effect of an environmental contaminant on fecundability. PMID:24812419

Psychometric properties and clinical cut-off scores of the Spanish version of the Social Anxiety Scale for Adolescents.

PubMed

Garcia-Lopez, Luis J; Inglés, Cándido J; García-Fernández, José M; Hidalgo, María D; Bermejo, Rosa; Puklek Levpušček, Melita

2011-01-01

This study examined the reliability and validity evidence drawn from the scores of the Spanish version of the Slovenian-developed Social Anxiety Scale for Adolescents (SASA; Puklek, 1997; Puklek & Vidmar, 2000) using a community sample (Study 1) and a clinical sample (Study 2). Confirmatory factor analysis in Study 1 replicated the 2-factor structure found by the original authors in a sample of Slovenian adolescents. Test-retest reliability was adequate. Furthermore, the SASA correlated significantly with other social anxiety scales, supporting concurrent validity evidence in Spanish adolescents. The results of Study 2 confirmed the correlations between the SASA and other social anxiety measures in a clinical sample. In addition, findings revealed that the SASA can effectively discriminate between adolescents with a clinical diagnosis of social anxiety disorder (SAD) and those without this disorder. Finally, cut-off scores for the SASA are provided for Spanish adolescents.

An experimental study on dynamic response for MICP strengthening liquefiable sands

NASA Astrophysics Data System (ADS)

Han, Zhiguang; Cheng, Xiaohui; Ma, Qiang

2016-12-01

The technology of bio-grouting is a new technique for soft ground improvement. Many researchers have carried out a large number of experiments and study on this topic. However, few studies have been carried out on the dynamic response of solidified sand samples, such reducing liquefaction in sand. To study this characteristic of microbial-strengthened liquefiable sandy foundation, a microorganism formula and grouting scheme is applied. After grouting, the solidified samples are tested via dynamic triaxial testing to examine the cyclic performance of solidified sand samples. The results indicate that the solidified sand samples with various strengths can be obtained to meet different engineering requirements, the use of bacteria solution and nutritive salt is reduced, and solidified time is shortened to 1-2 days. Most importantly, in the study of the dynamic response, it is found that the MICP grouting scheme is effective in improving liquefiable sand characteristic, such as liquefaction resistance.

Acoustically levitated droplets: a contactless sampling method for fluorescence studies.

PubMed

Leiterer, Jork; Grabolle, Markus; Rurack, Knut; Resch-Genger, Ute; Ziegler, Jan; Nann, Thomas; Panne, Ulrich

2008-01-01

Acoustic levitation is used as a new tool to study concentration-dependent processes in fluorescence spectroscopy. With this technique, small amounts of liquid and solid samples can be measured without the need for sample supports or containers, which often limits signal acquisition and can even alter sample properties due to interactions with the support material. We demonstrate that, because of the small sample volume, fluorescence measurements at high concentrations of an organic dye are possible without the limitation of inner-filter effects, which hamper such experiments in conventional, cuvette-based measurements. Furthermore, we show that acoustic levitation of liquid samples provides an experimentally simple way to study distance-dependent fluorescence modulations in semiconductor nanocrystals. The evaporation of the solvent during levitation leads to a continuous increase of solute concentration and can easily be monitored by laser-induced fluorescence.

Defining And Characterizing Sample Representativeness For DWPF Melter Feed Samples

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

Shine, E. P.; Poirier, M. R.

2013-10-29

Representative sampling is important throughout the Defense Waste Processing Facility (DWPF) process, and the demonstrated success of the DWPF process to achieve glass product quality over the past two decades is a direct result of the quality of information obtained from the process. The objective of this report was to present sampling methods that the Savannah River Site (SRS) used to qualify waste being dispositioned at the DWPF. The goal was to emphasize the methodology, not a list of outcomes from those studies. This methodology includes proven methods for taking representative samples, the use of controlled analytical methods, and datamore » interpretation and reporting that considers the uncertainty of all error sources. Numerous sampling studies were conducted during the development of the DWPF process and still continue to be performed in order to evaluate options for process improvement. Study designs were based on use of statistical tools applicable to the determination of uncertainties associated with the data needs. Successful designs are apt to be repeated, so this report chose only to include prototypic case studies that typify the characteristics of frequently used designs. Case studies have been presented for studying in-tank homogeneity, evaluating the suitability of sampler systems, determining factors that affect mixing and sampling, comparing the final waste glass product chemical composition and durability to that of the glass pour stream sample and other samples from process vessels, and assessing the uniformity of the chemical composition in the waste glass product. Many of these studies efficiently addressed more than one of these areas of concern associated with demonstrating sample representativeness and provide examples of statistical tools in use for DWPF. The time when many of these designs were implemented was in an age when the sampling ideas of Pierre Gy were not as widespread as they are today. Nonetheless, the engineers and statisticians used carefully thought out designs that systematically and economically provided plans for data collection from the DWPF process. Key shared features of the sampling designs used at DWPF and the Gy sampling methodology were the specification of a standard for sample representativeness, an investigation that produced data from the process to study the sampling function, and a decision framework used to assess whether the specification was met based on the data. Without going into detail with regard to the seven errors identified by Pierre Gy, as excellent summaries are readily available such as Pitard [1989] and Smith [2001], SRS engineers understood, for example, that samplers can be biased (Gy's extraction error), and developed plans to mitigate those biases. Experiments that compared installed samplers with more representative samples obtained directly from the tank may not have resulted in systematically partitioning sampling errors into the now well-known error categories of Gy, but did provide overall information on the suitability of sampling systems. Most of the designs in this report are related to the DWPF vessels, not the large SRS Tank Farm tanks. Samples from the DWPF Slurry Mix Evaporator (SME), which contains the feed to the DWPF melter, are characterized using standardized analytical methods with known uncertainty. The analytical error is combined with the established error from sampling and processing in DWPF to determine the melter feed composition. This composition is used with the known uncertainty of the models in the Product Composition Control System (PCCS) to ensure that the wasteform that is produced is comfortably within the acceptable processing and product performance region. Having the advantage of many years of processing that meets the waste glass product acceptance criteria, the DWPF process has provided a considerable amount of data about itself in addition to the data from many special studies. Demonstrating representative sampling directly from the large Tank Farm tanks is a difficult, if not unsolvable enterprise due to limited accessibility. However, the consistency and the adequacy of sampling and mixing at SRS could at least be studied under the controlled process conditions based on samples discussed by Ray and others [2012a] in Waste Form Qualification Report (WQR) Volume 2 and the transfers from Tanks 40H and 51H to the Sludge Receipt and Adjustment Tank (SRAT) within DWPF. It is important to realize that the need for sample representativeness becomes more stringent as the material gets closer to the melter, and the tanks within DWPF have been studied extensively to meet those needs.« less

Differential expression of extracellular matrix constituents and cell adhesion molecules between malignant pleural mesothelioma and mesothelial hyperplasia.

PubMed

Alì, Greta; Borrelli, Nicla; Riccardo, Giannini; Proietti, Agnese; Pelliccioni, Serena; Niccoli, Cristina; Boldrini, Laura; Lucchi, Marco; Mussi, Alfredo; Fontanini, Gabriella

2013-11-01

Malignant pleural mesothelioma (MPM) is a highly aggressive neoplasm associated with asbestos exposure. Currently, the molecular mechanisms that induce MPM development are still unknown. The purpose of this study was to identify new molecular biomarkers for mesothelial carcinogenesis. We analyzed a panel of 84 genes involved in extracellular matrix remodeling and cell adhesion by polymerase chain reaction (PCR) array in 15 samples of epithelioid mesothelioma and 10 samples of reactive mesothelial hyperplasia (MH; 3 of 25 samples were inadequate for mRNA analysis). To validate the differentially expressed genes identified by PCR array, we analyzed 27 more samples by immunohistochemistry, in addition to the 25 samples already studied. Twenty-five genes were differentially expressed in MPM and MH by PCR array. Of these we studied matrix metalloproteinase 7 (MMP7), MMP14, CD44, and integrin, alpha3 expression by immunohistochemistry in 26 epithelioid MPM and 26 MH samples from the entire series of 52 cases. We observed higher MMP14 and integrin, alpha3 expression in MPM samples compared with MH samples (p = 0.000002 and p = 0.000002, respectively). Conversely, CD44 expression was low in most (57.7%) mesothelioma samples but only in 11.5% of the MH samples (p = 0.0013). As regards MMP7, we did not observe differential expression between MH and MPM samples. We have extensively studied genes involved in cell adhesion and extracellular matrix remodeling in MPM and MH samples, gaining new insight into the pathophysiology of mesothelioma. Moreover, our data suggest that these factors could be potential biomarkers for MPM.

Ethnozoology in Brazil: analysis of the methodological risks in published studies.

PubMed

Lyra-Neves, R M; Santos, E M; Medeiros, P M; Alves, R R N; Albuquerque, U P

2015-11-01

There has been a growth in the field of Ethnozoology throughout the years, especially in Brazil, where a considerable number of scientific articles pertaining to this subject has been published in recent decades. With this increase in publications comes the opportunity to assess the quality of these publications, as there are no known studies assessing the methodological risks in this area. Based on this observation, our objectives were to compile the papers published on the subject of ethnozoology and to answer the following questions: 1) Do the Brazilian ethnozoological studies use sound sampling methods?; 2) Is the sampling quality influenced by characteristics of the studies/publications? The studies found in databases and using web search engines were compiled to answer these questions. The studies were assessed based on their nature, sampling methods, use of hypotheses and tests, journal's impact factor, and animal group studied. The majority of the studies analyzed exhibited problems associated with the samples, as 144 (66.98%) studies were classified as having a high risk of bias. With regard to the characteristics analyzed, we determined that a quantitative nature and the use of tests are essential components of good sampling. Most studies classified as moderate and low risk either did not provide these data or provided data that were not clear; therefore, these studies were classified as being of a quali-quantitative nature. Studies performed with vertebrate groups were of high risk. Most of the papers analyzed here focused on fish, insects, and/or mollusks, thus highlighting the difficulties associated with conducting interviews regarding tetrapod vertebrates. Such difficulties are largely related to the extremely strict Brazilian laws, justified by the decline and extinction of some species, related to the use of wild tetrapod vertebrates.

Preparing for chemical terrorism: stability of injectable atropine sulfate.

PubMed

Schier, Joshua G; Ravikumar, Padinjarekuttu R; Nelson, Lewis S; Heller, Michael B; Howland, Mary Ann; Hoffman, Robert S

2004-04-01

A massive nerve agent attack may rapidly deplete in-date supplies of atropine. The authors considered using atropine beyond its labeled shelf life. The objective was to determine the stability of premixed injectable atropine sulfate samples with different expiration dates. This was an in-vitro study using gas chromatography and mass spectrometry (GC/MS). Four atropine solutions (labeled concentration of 400 microg/mL) ranging from in date to 12 years beyond expiration (exp) and an additional sample of atropine sulfate (labeled concentration of 2,000 microg/mL) obtained from a World War II era autoinjector were assayed for atropine stability. Standards of atropine sulfate and tropine were prepared and quantified by GC/MS. Study samples were prepared by adding a buffer solution to free the base, extracting with an isopropanol/methylene chloride mixture and followed by evaporating the organic layer to dryness. Pentafluoropropionic anhydride and pentafluoropropanol were then added as derivatization reagents. Study samples were heated, the derivitization reagents were evaporated, and the remaining compound was reconstituted in ethyl acetate for injection into the GC/MS. All solutions were clear and colorless. Atropine concentrations were as follows: in date, 252 microg/mL; 2001 exp, 290 microg/mL; 1999 exp, 314 microg/mL; 1990 exp, 398 microg/mL; and WW II specimen, 1,475 microg/mL. Tropine was found in concentrations of <10 microg/mL in all study samples. Significant amounts of atropine were found in all study samples. All samples remained clear and colorless, and no substantial amount of tropine was found in any study sample. Further testing is needed to determine clinical effect.

Definition of intercultural competence (IC) in undergraduate students at a private university in the USA: A mixed-methods study.

PubMed

Gierke, Lioba; Binder, Nadine; Heckmann, Mark; Odağ, Özen; Leiser, Anne; Kedzior, Karina Karolina

2018-01-01

Intercultural competence (IC) is an important skill to be gained from higher education. However, it remains unclear what IC means to students and what factors might influence their definitions of IC. The aim of the current study was to qualitatively assess how students at one higher education institution in the USA define IC and to quantitatively test for relationships among IC components and various demographic characteristics, including intercultural experience and study context. A further aim was to descriptively compare the IC definitions from the US sample with the definitions obtained from another sample of university students in Germany. A purposive sample of n = 93 undergraduate, second semester students at Dickinson College, USA, participated in the study by completing an online questionnaire. The qualitative data were content-analyzed to define the dimensions of IC. The quantitative data were cluster-analyzed to assess the multivariate relationships among the IC components and the demographic characteristics of the sample. The most important dimensions of IC were Knowledge, External Outcomes (interaction, communication), and Attitudes (respect, tolerance) according to the US sample. The most frequently chosen dimensions of IC differed between both samples: Knowledge was chosen by the sample in the USA while External Outcomes was chosen by the sample in Germany. Relative to the US sample, significantly more students chose Attitudes, External Outcomes, and Intrapersonal Skills in the sample in Germany. The relationships among IC components and demographic characteristics were only weak in the US sample. A person with IC was rated as Open-minded and Respectful by students who lived predominantly in the USA or Tolerant and Curious by those who lived outside the USA for at least six months. The current results suggest that students residing in two countries (USA or Germany) define IC using similar dimensions. However, IC definitions may depend on the intercultural experience and the current global discourse. Longitudinal studies with representative samples are required to assess how IC definitions change over time.

Assessing the performance of a plastic optical fibre turbidity sensor for measuring post-fire erosion from plot to catchment scale

NASA Astrophysics Data System (ADS)

Keizer, J. J.; Martins, M. A. S.; Prats, S. A.; Santos, L. F.; Vieira, D. C. S.; Nogueira, R.; Bilro, L.

2015-09-01

This study is the first comprehensive testing of a novel plastic optical fibre turbidity sensor with runoff samples collected in the field and, more specifically, with a total of 158 streamflow samples and 925 overland flow samples from a recently burnt forest area in north-central Portugal, collected mainly during the first year after the wildfire, as well as with 56 overland flow samples from a nearby long-unburnt study site. Sediment concentrations differed less between overland flow and streamflow samples than between study sites and, at one study site, between plots with and without effective erosion mitigation treatments. Maximum concentrations ranged from 0.91 to 8.19 g L-1 for the micro-plot overland flow samples from the six burnt sites, from 1.74 to 8.99 g L-1 for the slope-scale overland flow samples from these same sites, and amounted to 4.55 g L-1 for the streamflow samples. Power functions provided (reasonably) good fits to the - expected - relationships of increasing normalized light loss with increasing sediment concentrations for the different sample types from individual study sites. The corresponding adjusted R2 values ranged from 0.64 to 0.81 in the case of the micro-plot samples from the six burnt sites, from 0.72 to 0.89 in the case of the slope-scale samples from these same sites, and was 0.85 in the case of the streamflow samples. While the overall performance of the sensor was thus rather satisfactory, the results pointed to the need for scale of site-specific calibrations to maximize the reliability of the predictions of sediment concentration by the POF (plastic optical fibre) sensor. This especially applied to the cases in which sediment concentrations were comparatively low, for example following mulching with forest residues.

Sample size calculation for a proof of concept study.

PubMed

Yin, Yin

2002-05-01

Sample size calculation is vital for a confirmatory clinical trial since the regulatory agencies require the probability of making Type I error to be significantly small, usually less than 0.05 or 0.025. However, the importance of the sample size calculation for studies conducted by a pharmaceutical company for internal decision making, e.g., a proof of concept (PoC) study, has not received enough attention. This article introduces a Bayesian method that identifies the information required for planning a PoC and the process of sample size calculation. The results will be presented in terms of the relationships between the regulatory requirements, the probability of reaching the regulatory requirements, the goalpost for PoC, and the sample size used for PoC.

Quality of shallow ground water in alluvial aquifers of the Willamette Basin, Oregon, 1993-95

USGS Publications Warehouse

Hinkle, Stephen R.

1997-01-01

The current (1993?95) quality of shallow ground water (generally, <25 meters below land surface) in Willamette Basin alluvium is described using results from two studies. A Study-Unit Survey, or regional assessment of shallow groundwater quality in alluvium, was done from June through August 1993. During the Study-Unit Survey, data were collected from 70 domestic wells chosen using a random-selection process and located mostly in areas of agricultural land use. An urban Land-Use Study, which was a reconnaissance of shallow urban ground-water quality from 10 monitoring wells installed in areas of residential land use, was done in July 1995. Concentrations of nitrite plus nitrate (henceforth, nitrate, because nitrite concentrations were low) ranged from <0.05 to 26 mg N/L (milligrams nitrogen per liter) in ground water from 70 Study-Unit-Survey wells; concentrations exceeded the U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Level (MCL) of 10 mg N/L in 9 percent of Study-Unit-Survey samples. Relationships were observed between nitrate concentrations and dissolved-oxygen concentrations, the amount of clay present within and overlying aquifers, overlying geology, and upgradient land use. Tritium (3H) data indicate that 21 percent of Study-Unit-Survey samples represented water recharged prior to 1953. Nitrogen-fertilizer application rates in the basin have increased greatly over the past several decades. Thus, some observed nitrate concentrations may reflect nitrogen loading rates that were smaller than those presently applied in the basin. Concentrations of phosphorus ranged from <0.01 to 2.2 mg/L in 70 Study-Unit-Survey wells and exceeded 0.10 mg/L in 60 percent of the samples. Phosphorus and nitrate concentrations were inversely correlated. From 1 to 5 pesticides and pesticide degradation products (henceforth, pesticides) were detected in ground water from each of 23 Study-Unit-Survey wells (33 percent of 69 wells sampled for pesticides) for a total of 51 pesticide detections. Thirteen different pesticides were detected; atrazine was the most frequently encountered pesticide. Although detections were widespread, concentrations were low (generally <1,000 ng/L [nanograms per liter]). (One ng/L is equal to 0.001 mg/L [micrograms per liter].) One detection (dinoseb, at 7,900 ng/L) exceeded a USEPA MCL. Relationships were observed between the occurrence of pesticides and the amount of clay present within and overlying aquifers, overlying geology, and land use. Between 1 and 5 volatile organic compounds (VOCs) were detected at each of 7 Study-Unit-Survey sites (11 percent of 65 sites evaluated), for a total of 14 VOC detections. One detection (tetrachloroethylene, at 29 mg/L) exceeded a USEPA MCL. Other detections were at low concentrations (0.2 to 2.0 mg/L). VOC detections generally were from sites associated with urban land use. Concentrations of arsenic ranged from <1 to 13 mg/L in 70 Study-Unit-Survey wells. Concentrations in 16 percent of samples exceeded the USEPA Risk-Specific-Dose Health Advisory of 2 mg/L. Radon concentrations ranged from 200 to 1,200 pCi/L (picocuries per liter) in 51 Study-Unit-Survey wells. All samples exceeded the USEPA Risk-Specific-Dose Health Advisory of 150 pCi/L. All urban Land-Use-Study samples were well oxygenated; thus, nitrate reduction probably did not affect these samples. Urban Land-Use-Study nitrate concentrations were similar to those of the well oxygenated, agricultural subset of Study-Unit-Survey samples. Pesticides were detected in samples from three urban Land-Use-Study sites, but concentrations were low (1 to 5 ng/L). In contrast, VOCs were detected in ground water from 80 percent of urban Land-Use-Study wells; concentrations ranged up to 7.6 mg/L. Trace-element concentrations in the urban Land-Use Study samples were low. Median concentrations consistently were <10 mg/L and frequently were <1 mg/L

Nitric Oxide Measurement Study. Volume II. Probe Methods,

DTIC Science & Technology

1980-05-01

case of the Task I study, it should be pointed out that at lower gas temperatures where much of the study was performed, the mass flow through the...third body as pointed out by Matthews, et al. (1977) but also dependent on the viscosity of the sampled gas for standard commercial units (Folsom and...substantially above the dew point (based on the maximum pressure in the sampling system and the initial water concentration) or (2) sample line and

The French Version of the Modified-Checklist for Autism in Toddlers (M-CHAT): A Validation Study on a French Sample of 24 Month-Old Children

ERIC Educational Resources Information Center

Baduel, Sophie; Guillon, Quentin; Afzali, Mohammad H.; Foudon, Nadège; Kruck, Jeanne; Rogé, Bernadette

2017-01-01

Early ASD screening has the potential to reduce delays between initial parental concerns and diagnosis, and promote early intervention. The aim of this study was to validate the M-CHAT on a French population sample of 24 month-old children. This study included a low-risk sample of 1,227 children. A total of 20 children screened positive on the…

Encouragement of Early Academic Skills at Home during Early Childhood Period: Validity and Reliability Study of the EASYC Scale

ERIC Educational Resources Information Center

Kara, H. Gözde Ertürk; Çoksoyluer, Seyda Kiliç

2017-01-01

The current study aims to perform the adaptation of the Encouragement of Academic Skills of Young Children (EASYC) Scale into Turkish. The study group was determined by means of the convenience sampling technique. A total of 124 students aged at 48-84 months were included in the sampling of the study. The data collection tools of the study are the…

The theoretical and experimental study of a material structure evolution in gigacyclic fatigue regime

NASA Astrophysics Data System (ADS)

Plekhov, Oleg; Naimark, Oleg; Narykova, Maria; Kadomtsev, Andrey; Betekhtin, Vladimir

2015-10-01

The work is devoted to the study of the metal structure evolution under gigacyclic fatigue (VHCF) regime. The study of the mechanical properties of the samples (Armco iron) with different state of life time existing was carried out on the base of the acoustic resonance method. The damage accumulation (porosity of the samples) was studied by the hydrostatic weighing method. A statistical model of damage accumulation was proposed in order to describe the damage accumulation process. The model describes the influence of the sample surface on the location of fatigue crack initiation.

Nonprobability and probability-based sampling strategies in sexual science.

PubMed

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

2015-01-01

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

Molecular epidemiology biomarkers-Sample collection and processing considerations

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

Holland, Nina T.; Pfleger, Laura; Berger, Eileen

2005-08-07

Biomarker studies require processing and storage of numerous biological samples with the goals of obtaining a large amount of information and minimizing future research costs. An efficient study design includes provisions for processing of the original samples, such as cryopreservation, DNA isolation, and preparation of specimens for exposure assessment. Use of standard, two-dimensional and nanobarcodes and customized electronic databases assure efficient management of large sample collections and tracking results of data analyses. Standard operating procedures and quality control plans help to protect sample quality and to assure validity of the biomarker data. Specific state, federal and international regulations are inmore » place regarding research with human samples, governing areas including custody, safety of handling, and transport of human samples. Appropriate informed consent must be obtained from the study subjects prior to sample collection and confidentiality of results maintained. Finally, examples of three biorepositories of different scale (European Cancer Study, National Cancer Institute and School of Public Health Biorepository, University of California, Berkeley) are used to illustrate challenges faced by investigators and the ways to overcome them. New software and biorepository technologies are being developed by many companies that will help to bring biological banking to a new level required by molecular epidemiology of the 21st century.« less

On the Link Between Emotionally Driven Impulsivity and Aggression: Evidence From a Validation Study on the Dutch UPPS-P.

PubMed

Bousardt, A M C; Noorthoorn, E O; Hoogendoorn, A W; Nijman, H L I; Hummelen, J W

2018-06-01

The UPPS-P seems to be a promising instrument for measuring different domains of impulsivity in forensic psychiatric patients. Validation studies of the instrument however, have been conducted only in student groups. In this validation study, three groups completed the Dutch UPPS-P: healthy student ( N = 94) and community ( N = 134) samples and a forensic psychiatric sample ( N = 73). The five-factor structure reported previously could only be substantiated in a confirmatory factor analysis over the combined groups but not in the subsamples. Subgroup sample sizes might be too small to allow such complex analyses. Internal consistency, as assessed by Cronbach's alpha, was high on most subscale and sample combinations. In explaining aggression, especially the initial subscale negative urgency (NU) was related to elevated scores on self-reported aggression in the healthy samples (student and community). The current study is the second study that found a relationship between self-reported NU and aggression highlighting the importance of addressing this behavioural domain in aggression management therapy.

Collaborative study using common samples to evaluate the performance of anti-drug antibody assays constructed by different companies.

PubMed

Niimi, Shingo; Nishimiya, Kazuhiro; Nishidate, Masanobu; Saito, Tetsu; Minoura, Kyoko; Kadotsuji, Kenta; Shimakura, Jin; Shigemizu, Hiroko; Hosogi, Jun; Adachi, Maiko; Hashimoto, Tsutomu; Mori, Tamiki; Harada, Hideki; Yamamoto, Ken-Ichi; Nakamura, Takahiro; Nomura, Tatsuki; Yamaguchi, Itadaki; Sonehara, Kazuhiko; Ishii-Watabe, Akiko; Kawasaki, Nana

2018-04-01

This study was undertaken to evaluate the performance of anti-drug antibody (ADA) assays constructed by each participating company using common samples including ADA, drug and human serum. The ADA assays constructed by each company showed good sensitivity and precision for evaluation of ADA. Cut points for screening and confirmatory assays and assay selectivity were determined by various calculation methods. In evaluations of blind ADA samples, nearly similar results were obtained by the study companies in determinations of whether samples were positive or negative except at the lowest sample concentration (5 ng/mL). In measurement of drug tolerance, for almost samples containing ADA and drugs, more positive results were obtained in assays using acid dissociation compared to those without acid dissociation. Overall, the performance of ADA assays constructed by the 10 companies participating in this study was acceptable in terms of sensitivity and reproducibility for detection and evaluation of immunogenicity in both patients and healthy subjects. On the other hand, based on results for samples containing ADA and drugs, validity of results for ADA assays conducted without acid dissociation was less meaningful and more difficult to evaluate. Thus, acid dissociation was confirmed to be useful for improving drug tolerance. Copyright © 2018 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.

Research on stored biological samples: views of African American and White American cancer patients.

PubMed

Pentz, Rebecca D; Billot, Laurent; Wendler, David

2006-04-01

Proposals on consent for research with biological samples should be informed by empirical studies of individuals' views. Studies to date queried mostly white research subjects. The aim of this study was to compare the views of two groups of patients: cancer patients at a university clinic (Winship Cancer Institute at Emory Healthcare) and cancer patients at an inner city county hospital (Grady) who were given the option of tissue banking. Overall, 315/452 (70%) patients completed the survey. The Grady cohort was 86% African American; the Winship cohort was 82% White. The vast majority (95%) of individuals in both cohorts agreed to provide a biological sample for future research. Both cohorts were willing for their samples to be used to study cancer and other diseases, including Alzheimer disease. Few participants preferred to control the disease to be studied (10%) or wished to be contacted again for consent for each future research project (11%). In our sample, almost all clinical patients, regardless of site of care, ethnicity or socioeconomic status, were willing to provide a biological sample for research purposes and allow investigators to determine the research to be done without contacting the patients again. These findings support the recommendation to offer individuals a simplified consent with a one-time binary choice whether to provide biological samples for future research. Copyright 2006 Wiley-Liss, Inc.

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

PubMed

Bhagavatula, Jyotsna; Singh, Lalji

2006-10-17

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

Bacterial water quality and network hydraulic characteristics: a field study of a small, looped water distribution system using culture-independent molecular methods.

PubMed

Sekar, R; Deines, P; Machell, J; Osborn, A M; Biggs, C A; Boxall, J B

2012-06-01

To determine the spatial and temporal variability in the abundance, structure and composition of planktonic bacterial assemblages sampled from a small, looped water distribution system and to interpret results with respect to hydraulic conditions. Water samples were collected from five sampling points, twice a day at 06:00 h and 09:00 h on a Monday (following low weekend demand) and a Wednesday (higher midweek demand). All samples were fully compliant with current regulated parameter standards. This study did not show obvious changes in bacterial abundance (DAPI count) or community structure Denaturing gradient gel electrophoresis analysis with respect to sample site and hence to water age; however, the study did show temporal variability with respect to both sampling day and sample times. Data suggests that variations in the bacterial assemblages may be associated with the local system hydraulics: the bacterial composition and numbers, over short durations, are governed by the interaction of the bulk water and the biofilm influenced by the hydraulic conditions. This study demonstrates general stability in bacterial abundance, community structure and composition within the system studied. Trends and patterns supporting the transfer of idealized understanding to the real world were evident. Ultimately, such work will help to safeguard potable water quality, fundamental to public health. © 2012 The Authors. Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

Characterization and Beneficiation Studies of a Low Grade Bauxite Ore

NASA Astrophysics Data System (ADS)

Rao, D. S.; Das, B.

2014-10-01

A low grade bauxite sample of central India was thoroughly characterized with the help of stereomicroscope, reflected light microscope and electron microscope using QEMSCAN. A few hand picked samples were collected from different places of the mine and were subjected to geochemical characterization studies. The geochemical studies indicated that most of the samples contain high silica and low alumina, except a few which are high grade. Mineralogically the samples consist of bauxite (gibbsite and boehmite), ferruginous mineral phases (goethite and hematite), clay and silicate (quartz), and titanium bearing minerals like rutile and ilmenite. Majority of the gibbsite, boehmite and gibbsitic oolites contain clay, quartz and iron and titanium mineral phases within the sample as inclusions. The sample on an average contains 39.1 % Al2O3 and 12.3 % SiO2, and 20.08 % of Fe2O3. Beneficiation techniques like size classification, sorting, scrubbing, hydrocyclone and magnetic separation were employed to reduce the silica content suitable for Bayer process. The studies indicated that, 50 % by weight with 41 % Al2O3 containing less than 5 % SiO2 could be achieved. The finer sized sample after physical beneficiation still contains high silica due to complex mineralogical associations.

A males only clinic session.

PubMed

Stupples, A

1980-01-01

The pressure to establish the Dunedin (New Zealand) Male Advice Clinic came from members of the Psychology Department of the University of Otago as a result of a study of attitudes towards the use and purchase of contraceptives among the local young people. The study findings and the suggestions made for the establishment of a male advice center are summarized. 3 samples were studied: a university sample (N=80); a sample of high school students (N=243); and a general population sample (N=70). The males in all samples were questioned regarding the process of purchasing contraceptives. The study findings indicated that embarrassment functioned as an impediment to obtaining contraceptive supplies. 76% of the university sample, 36% of the school sample, and 57% of the general population thought that males needed advice in choosing condoms. The male advice center would be open to anyone but designed specifically to cater to young men who anticipate or are already engaged in sexual intercourse. Services available would include contraceptive advice, contraceptive supplies, and sexual advice and counseling. Initial interest in the Dunedin Male Advice Clinic was considerable, but the question remained as to whether the group for whom the clinic was intended was really reached.

Microbial Communities in Pre-Columbian Coprolites

PubMed Central

Santiago-Rodriguez, Tasha M.; Narganes-Storde, Yvonne M.; Chanlatte, Luis; Crespo-Torres, Edwin; Toranzos, Gary A.; Jimenez-Flores, Rafael; Hamrick, Alice; Cano, Raul J.

2013-01-01

The study of coprolites from earlier cultures represents a great opportunity to study an “unaltered” composition of the intestinal microbiota. To test this, pre-Columbian coprolites from two cultures, the Huecoid and Saladoid, were evaluated for the presence of DNA, proteins and lipids by cytochemical staining, human and/or dog-specific Bacteroides spp. by PCR, as well as bacteria, fungi and archaea using Terminal Restriction Fragment analyses. DNA, proteins and lipids, and human-specific Bacteroides DNA were detected in all coprolites. Multidimensional scaling analyses resulted in spatial arrangements of microbial profiles by culture, further supported by cluster analysis and ANOSIM. Differences between the microbial communities were positively correlated with culture, and SIMPER analysis indicated 68.8% dissimilarity between the Huecoid and Saladoid. Proteobacteria, Bacteroidetes and methanogens were found in all coprolite samples. Propionebacteria, Shewanella and lactic acid bacteria dominated in the Huecoid samples, while Acidobacteria, and peptococci were dominant in Saladoid samples. Yeasts, including Candida albicans and Crypotococcus spp. were found in all samples. Basidiomycetes were the most notable fungi in Huecoid samples while Ascomycetes predominated in Saladoid samples, suggesting differences in dietary habits. Our study provides an approach for the study of the microbial communities of coprolite samples from various cultures. PMID:23755194

Sample size of the reference sample in a case-augmented study.

PubMed

Ghosh, Palash; Dewanji, Anup

2017-05-01

The case-augmented study, in which a case sample is augmented with a reference (random) sample from the source population with only covariates information known, is becoming popular in different areas of applied science such as pharmacovigilance, ecology, and econometrics. In general, the case sample is available from some source (for example, hospital database, case registry, etc.); however, the reference sample is required to be drawn from the corresponding source population. The required minimum size of the reference sample is an important issue in this regard. In this work, we address the minimum sample size calculation and discuss related issues. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--LIST OF STANDARD OPERATING PROCEDURES

EPA Science Inventory

This document lists available protocols and SOPs for the U.S.-Mexico Border Program study. It identifies protocols and SOPs for the following study components: (1) Sample collection and field operations, (2) Sample analysis, (3) General laboratory procedures, (4) Quality Assuranc...

Sampling bias in blending validation and a different approach to homogeneity assessment.

PubMed

Kraemer, J; Svensson, J R; Melgaard, H

1999-02-01

Sampling of batches studied for validation is reported. A thief particularly suited for granules, rather than cohesive powders, was used in the study. It is shown, as has been demonstrated in the past, that traditional 1x to 3x thief sampling of a blend is biased, and that the bias decreases as the sample size increases. It is shown that taking 50 samples of tablets after blending and testing this subpopulation for normality is a discriminating manner of testing for homogeneity. As a criterion, it is better than sampling at mixer or drum stage would be even if an unbiased sampling device were available.

A study on rate of infestation to Sarcocystis cysts in supplied raw hamburgers.

PubMed

Nematollahia, Ahmad; Khoshkerdar, Afsaneh; Helan, Javad Ashrafi; Shahbazi, Parisa; Hassanzadeh, Parviz

2015-06-01

This study was carried on for determination of presence of Sarcocystis cysts in raw hamburgers in Tabriz North West of Iran. Ninety-six samples of industrial (70 % meat content) and traditional (30 % meat content) hamburgers (80 samples industrial and 16 samples traditional) were obtained from retail fast food stores. The samples were examined by gross examination, and microscopic examination methods consist impression smear and peptic digestion. Macroscopic cysts did not observed in any of the samples in gross examination. Microscopic study showed that from 96 samples 54 (56.25 %) samples were infected by at least one bradyzoites of Sarcocystis. From 54 infected samples, 45 industrial hamburgers and nine traditional hamburgers samples were infected. Statistical analysis showed that there was not significant differences between industrial and traditional hamburgers in infection to Sarcocystis. Infestation of hamburgers to Sarcocystis in summer was higher than other seasons but this difference was not significant. In Iran, beef meat is used for preparation of 70 % of hamburger and infestation of cattle to sarcocystosis was reported in many investigations in Iran. With regard to the high prevalence of Sarcocystis infection in meat products such as hamburgers in this study, it is strongly recommended to avoid eating raw or under-cooked hamburgers or keep them at freezing temperature for at least 3-5 days.

Concentrated ERP Delivered in a Group Setting: A Replication Study.

PubMed

Havnen, Audun; Hansen, Bjarne; Öst, Lars-Göran; Kvale, Gerd

2017-09-01

In a previous effectiveness study (Havnen et al., 2014), 35 obsessive compulsive disorder (OCD) patients underwent Concentrated Exposure Treatment (cET), which is a newly developed group treatment format delivered over four consecutive days. The primary aims of the present study were to evaluate the treatment results for a new sample of OCD patients receiving the cET treatment approach and to replicate the effectiveness study described in Havnen et al. (2014). Forty-two OCD patients underwent cET treatment. Treatment was delivered by different therapists than in Havnen et al. (2014), except for two groups led by the developers of the treatment. Assessments of OCD symptom severity, treatment satisfaction, and occupational impairment were included. The results showed a significant reduction in Yale-Brown Obsessive Compulsive Scale scores from pre-treatment to post-treatment, which was maintained at 6-month follow-up. At post-treatment, 74% of the sample was remitted; at 6-month follow-up, 60% were recovered. The sample showed a very high degree of overall treatment satisfaction. The results from the present study were statistically compared with those obtained in the previous study. The analyses showed that the study samples had comparable demographic data and equal application of treatment. The outcome of the present and original study did not differ significantly on primary and secondary outcome measures. This study shows that cET was successfully replicated in a new patient sample treated by different therapists than the original study. The results indicate that cET is well accepted by the patients, and the potential for dissemination is discussed.

A descriptive study of sexual homicide in Canada: implications for police investigation.

PubMed

Beauregard, Eric; Martineau, Melissa

2013-12-01

Few empirical studies have been conducted that examine the phenomenon of sexual homicide, and among these studies, many have been limited by small sample size. Although interesting and informative, these studies may not be representative of the greater phenomenon of sexual murder and may be subject to sampling bias that could have significant effects on results. The current study aims to provide a descriptive analysis of the largest sample of sexual homicide cases across Canada in the past 62 years. In doing so, the study aims to examine offender and victim characteristics, victim targeting and access, and modus operandi. Findings show that cases of sexual homicide and sexual murderers included in the current study differ in many aspects from the portrait of the sexual murderer and his or her crime depicted in previous studies. The authors' results may prove useful to the police officers responsible for the investigation of these crimes.

Disentangling the relationship between child maltreatment and violent delinquency: using a nationally representative sample.

PubMed

Yun, Ilhong; Ball, Jeremy D; Lim, Hyeyoung

2011-01-01

This study uses the National Longitudinal Study of Adolescents (Add Health) data, a nationally representative sample of adolescents, to disentangle the relationship between child maltreatment and violent delinquency. Also examined are potential moderating effects of gender, socioeconomic status (SES), and religiosity on the association between child maltreatment and violent delinquency. Contrary to prior research findings, the current analyses reveal that physical abuse is not associated with future violent delinquency, whereas sexual abuse and neglect predict violent delinquency significantly. The current study also did not reveal any moderating effects of gender, SES, and religiosity on the association between maltreatment and violent delinquency. Interpretations of these findings are presented, drawing on the properties of the national probability sample compared to the findings of most prior studies that used localized samples.

Health workers cohort study: methods and study design.

PubMed

Denova-Gutiérrez, Edgar; Flores, Yvonne N; Gallegos-Carrillo, Katia; Ramírez-Palacios, Paula; Rivera-Paredez, Berenice; Muñoz-Aguirre, Paloma; Velázquez-Cruz, Rafael; Torres-Ibarra, Leticia; Meneses-León, Joacim; Méndez-Hernández, Pablo; Hernández-López, Rubí; Salazar-Martínez, Eduardo; Talavera, Juan O; Tamayo, Juan; Castañón, Susana; Osuna-Ramírez, Ignacio; León-Maldonado, Leith; Flores, Mario; Macías, Nayeli; Antúnez, Daniela; Huitrón-Bravo, Gerardo; Salmerón, Jorge

2016-01-01

To examine different health outcomes that are associated with specific lifestyle and genetic factors. From March 2004 to April 2006, a sample of employees from three different health and academic institutions, as well as their family members, were enrolled in the study after providing informed consent. At baseline and follow-up (2010-2013), participants completed a self-administered questionnaire, a physical examination, and provided blood samples. A total of 10 729 participants aged 6 to 94 years were recruited at baseline. Of these, 70% were females, and 50% were from the Mexican Social Security Institute. Nearly 42% of the adults in the sample were overweight, while 20% were obese. Our study can offer new insights into disease mechanisms and prevention through the analysis of risk factor information in a large sample of Mexicans.

Percent recoveries of anthropogenic organic compounds with and without the addition of ascorbic acid to preserve finished-water samples containing free chlorine, 2004-10

USGS Publications Warehouse

Valder, Joshua F.; Delzer, Gregory C.; Bender, David A.; Price, Curtis V.

2011-01-01

This report presents finished-water matrix-spike recoveries of 270 anthropogenic organic compounds with and without the addition of ascorbic acid to preserve water samples containing free chlorine. Percent recoveries were calculated using analytical results from a study conducted during 2004-10 for the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS). The study was intended to characterize the effect of quenching on finished-water matrix-spike recoveries and to better understand the potential oxidation and transformation of 270 anthropogenic organic compounds. The anthropogenic organic compounds studied include those on analytical schedules 1433, 2003, 2033, 2060, 2020, and 4024 of the USGS National Water Quality Laboratory. Three types of samples were collected from 34 NAWQA locations across the Nation: (1) quenched finished-water samples (not spiked), (2) quenched finished-water matrix-spike samples, and (3) nonquenched finished-water matrix-spike samples. Percent recoveries of anthropogenic organic compounds in quenched and nonquenched finished-water matrix-spike samples are presented. Comparisons of percent recoveries between quenched and nonquenched spiked samples can be used to show how quenching affects finished-water samples. A maximum of 18 surface-water and 34 groundwater quenched finished-water matrix-spike samples paired with nonquenched finished-water matrix-spike samples were analyzed. Percent recoveries for the study are presented in two ways: (1) finished-water matrix-spike samples supplied by surface-water or groundwater, and (2) by use (or source) group category for surface-water and groundwater supplies. Graphical representations of percent recoveries for the quenched and nonquenched finished-water matrix-spike samples also are presented.

Comparing Microbiome Sampling Methods in a Wild Mammal: Fecal and Intestinal Samples Record Different Signals of Host Ecology, Evolution

PubMed Central

Ingala, Melissa R.; Simmons, Nancy B.; Wultsch, Claudia; Krampis, Konstantinos; Speer, Kelly A.; Perkins, Susan L.

2018-01-01

The gut microbiome is a community of host-associated symbiotic microbes that fulfills multiple key roles in host metabolism, immune function, and tissue development. Given the ability of the microbiome to impact host fitness, there is increasing interest in studying the microbiome of wild animals to better understand these communities in the context of host ecology and evolution. Human microbiome research protocols are well established, but wildlife microbiome research is still a developing field. Currently, there is no standardized set of best practices guiding the collection of microbiome samples from wildlife. Gut microflora are typically sampled either by fecal collection, rectal swabbing, or by destructively sampling the intestinal contents of the host animal. Studies rarely include more than one sampling technique and no comparison of these methods currently exists for a wild mammal. Although some studies have hypothesized that the fecal microbiome is a nested subset of the intestinal microbiome, this hypothesis has not been formally tested. To address these issues, we examined guano (feces) and distal intestinal mucosa from 19 species of free-ranging bats from Lamanai, Belize, using 16S rRNA amplicon sequencing to compare microbial communities across sample types. We found that the diversity and composition of intestine and guano samples differed substantially. In addition, we conclude that signatures of host evolution are retained by studying gut microbiomes based on mucosal tissue samples, but not fecal samples. Conversely, fecal samples retained more signal of host diet than intestinal samples. These results suggest that fecal and intestinal sampling methods are not interchangeable, and that these two microbiotas record different information about the host from which they are isolated. PMID:29765359

Comparing Microbiome Sampling Methods in a Wild Mammal: Fecal and Intestinal Samples Record Different Signals of Host Ecology, Evolution.

PubMed

Ingala, Melissa R; Simmons, Nancy B; Wultsch, Claudia; Krampis, Konstantinos; Speer, Kelly A; Perkins, Susan L

2018-01-01

The gut microbiome is a community of host-associated symbiotic microbes that fulfills multiple key roles in host metabolism, immune function, and tissue development. Given the ability of the microbiome to impact host fitness, there is increasing interest in studying the microbiome of wild animals to better understand these communities in the context of host ecology and evolution. Human microbiome research protocols are well established, but wildlife microbiome research is still a developing field. Currently, there is no standardized set of best practices guiding the collection of microbiome samples from wildlife. Gut microflora are typically sampled either by fecal collection, rectal swabbing, or by destructively sampling the intestinal contents of the host animal. Studies rarely include more than one sampling technique and no comparison of these methods currently exists for a wild mammal. Although some studies have hypothesized that the fecal microbiome is a nested subset of the intestinal microbiome, this hypothesis has not been formally tested. To address these issues, we examined guano (feces) and distal intestinal mucosa from 19 species of free-ranging bats from Lamanai, Belize, using 16S rRNA amplicon sequencing to compare microbial communities across sample types. We found that the diversity and composition of intestine and guano samples differed substantially. In addition, we conclude that signatures of host evolution are retained by studying gut microbiomes based on mucosal tissue samples, but not fecal samples. Conversely, fecal samples retained more signal of host diet than intestinal samples. These results suggest that fecal and intestinal sampling methods are not interchangeable, and that these two microbiotas record different information about the host from which they are isolated.

Validation of Networks Derived from Snowball Sampling of Municipal Science Education Actors

ERIC Educational Resources Information Center

von der Fehr, Ane; Sølberg, Jan; Bruun, Jesper

2018-01-01

Social network analysis (SNA) has been used in many educational studies in the past decade, but what these studies have in common is that the populations in question in most cases are defined and known to the researchers studying the networks. Snowball sampling is an SNA methodology most often used to study hidden populations, for example, groups…

A Study on the Evaluation of the Applicability of an Environmental Education Modular Curriculum

ERIC Educational Resources Information Center

Artun, Hüseyin; Özsevgeç, Tuncay

2016-01-01

The purpose of this study was, in line with the views of the students & teacher, to examine Environmental Education Modular Curriculum (EEMC) developed to give environmental education with a specific content. In the study, the case study method was used. The research sample was determined with the purposeful sampling method & made up of 23…

ICT Competence and Lecturers' Job Efficacy: A Study of Two Universities in Nigeria

ERIC Educational Resources Information Center

Akpan, Charles P.

2014-01-01

The study sought to establish the influence of ICT competence on lecturers' job efficacy in two universities in Nigeria. The sample of the study consisted of 500 university teachers randomly sampled from a population of 1,795 teachers. The results of the study revealed that male and female lecturers did not differ significantly in their level of…

Evolving Curricular Models in Culinary Arts: An Instrumental Case Study of a Technical Field

ERIC Educational Resources Information Center

Cossio, Allison

2016-01-01

The purpose of this research study was to examine how chefs and other individuals in the food industry understood the field of culinary arts. This study used an instrumental case study with purposeful sampling of multiple cases. Through a series of open-ended interviews using snowball-sampling strategy that concluded with 45 participants sharing…

Investigating Test Equating Methods in Small Samples through Various Factors

ERIC Educational Resources Information Center

Asiret, Semih; Sünbül, Seçil Ömür

2016-01-01

In this study, equating methods for random group design using small samples through factors such as sample size, difference in difficulty between forms, and guessing parameter was aimed for comparison. Moreover, which method gives better results under which conditions was also investigated. In this study, 5,000 dichotomous simulated data…

Who Are We Studying? Sample Diversity in Teaching of Psychology Research

ERIC Educational Resources Information Center

Richmond, Aaron S.; Broussard, Kristin A.; Sterns, Jillian L.; Sanders, Kristina K.; Shardy, Justin C.

2015-01-01

The purpose of the current study was to examine the sample diversity of empirical articles published in four premier teaching of psychology journals from 2008 to 2013. We investigated which demographic information was commonly reported and if samples were ethnically representative and whether gender was representative compared to National…

Sampling Methods and the Accredited Population in Athletic Training Education Research

ERIC Educational Resources Information Center

Carr, W. David; Volberding, Jennifer

2009-01-01

Context: We describe methods of sampling the widely-studied, yet poorly defined, population of accredited athletic training education programs (ATEPs). Objective: There are two purposes to this study; first to describe the incidence and types of sampling methods used in athletic training education research, and second to clearly define the…

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR CUSTODY OF FIELD SAMPLES (UA-C-1.0)

EPA Science Inventory

The purpose of this SOP is to outline sample custody guidelines used by the Arizona Border Study. This procedure was followed to maintain sample integrity and ensure consistent data retrieval, transport, storage, shipment, and analysis during the Arizona NHEXAS project and the B...

THE MUTATION SPECTRA OF DRINKING WATER SAMPLES USING THE BASE-SPECIFIC TA7000 STRAINS OF SALMONELLA IN THE MICROSUSPENSION ASSAY

EPA Science Inventory

Previous studies showed that disinfected drinking water samples gave mutagenic spectra typical of halogenated furanones. In this study, we used the TA7000 base-¿specific Salmonella typhimurium tester strains to characterize water samples from two drinking water treatment plants (...

Synthesizing Information from Language Samples and Standardized Tests in School-Age Bilingual Assessment

ERIC Educational Resources Information Center

Ebert, Kerry Danahy; Pham, Giang

2017-01-01

Purpose: Although language samples and standardized tests are regularly used in assessment, few studies provide clinical guidance on how to synthesize information from these testing tools. This study extends previous work on the relations between tests and language samples to a new population--school-age bilingual speakers with primary language…

MEASUREMENT OF CHILDREN'S EXPOSURE TO PESTICIDES: ANALYSIS OF URINARY METABOLITE LEVELS IN A PROBABILITY-BASED SAMPLE

EPA Science Inventory

The Minnesota Children's Pesticide Exposure Study is a probability-based sample of 102 children 3-13 years old who were monitored for commonly used pesticides. During the summer of 1997, first-morning-void urine samples (1-3 per child) were obtained for 88% of study children a...

Technology Tips: Sample Too Small? Probably Not!

ERIC Educational Resources Information Center

Strayer, Jeremy F.

2013-01-01

Statistical studies are referenced in the news every day, so frequently that people are sometimes skeptical of reported results. Often, no matter how large a sample size researchers use in their studies, people believe that the sample size is too small to make broad generalizations. The tasks presented in this article use simulations of repeated…

Steroidal hormones and other endocrine active compounds in shallow groundwater in nonagricultural areas of Minnesota—Study design, methods, and data, 2009–10

USGS Publications Warehouse

Erickson, Melinda L.

2012-01-01

The U.S. Geological Survey, in cooperation with the Minnesota Pollution Control Agency, completed a study on the occurrence of steroidal hormones and other endocrine active compounds in shallow groundwater in nonagricultural areas of Minnesota during 2009–10. This report describes the study design and methods, and presents the data collected on steroidal hormones and other related compounds. Environmental and quality-control samples were collected from 40 wells as part of this study. Samples were analyzed by the U.S. Geological Survey National Water Quality Laboratory for 16 steroidal hormones and 4 other related compounds, of which all but 2 compounds are endocrine active compounds. Most of the water samples did not contain detectable concentrations of any of the 20 compounds analyzed. Water samples from three wells had detectable concentrations of one or more compounds. Bisphenol A was detected in samples from three wells, and trans-diethylstilbestrol was detected in one of the samples in which bisphenol A also was detected.

Inactivation of RNA Viruses by Gamma Irradiation: A Study on Mitigating Factors

PubMed Central

Hume, Adam J.; Ames, Joshua; Rennick, Linda J.; Duprex, W. Paul; Marzi, Andrea; Tonkiss, John; Mühlberger, Elke

2016-01-01

Effective inactivation of biosafety level 4 (BSL-4) pathogens is vital in order to study these agents safely. Gamma irradiation is a commonly used method for the inactivation of BSL-4 viruses, which among other advantages, facilitates the study of inactivated yet morphologically intact virions. The reported values for susceptibility of viruses to inactivation by gamma irradiation are sometimes inconsistent, likely due to differences in experimental protocols. We analyzed the effects of common sample attributes on the inactivation of a recombinant vesicular stomatitis virus expressing the Zaire ebolavirus glycoprotein and green fluorescent protein. Using this surrogate virus, we found that sample volume and protein content of the sample modulated viral inactivation by gamma irradiation but that air volume within the sample container and the addition of external disinfectant surrounding the sample did not. These data identify several factors which alter viral susceptibility to inactivation and highlight the usefulness of lower biosafety level surrogate viruses for such studies. Our results underscore the need to validate inactivation protocols of BSL-4 pathogens using “worst-case scenario” procedures to ensure complete sample inactivation. PMID:27455307

Genome-wide association analysis of secondary imaging phenotypes from the Alzheimer's disease neuroimaging initiative study.

PubMed

Zhu, Wensheng; Yuan, Ying; Zhang, Jingwen; Zhou, Fan; Knickmeyer, Rebecca C; Zhu, Hongtu

2017-02-01

The aim of this paper is to systematically evaluate a biased sampling issue associated with genome-wide association analysis (GWAS) of imaging phenotypes for most imaging genetic studies, including the Alzheimer's Disease Neuroimaging Initiative (ADNI). Specifically, the original sampling scheme of these imaging genetic studies is primarily the retrospective case-control design, whereas most existing statistical analyses of these studies ignore such sampling scheme by directly correlating imaging phenotypes (called the secondary traits) with genotype. Although it has been well documented in genetic epidemiology that ignoring the case-control sampling scheme can produce highly biased estimates, and subsequently lead to misleading results and suspicious associations, such findings are not well documented in imaging genetics. We use extensive simulations and a large-scale imaging genetic data analysis of the Alzheimer's Disease Neuroimaging Initiative (ADNI) data to evaluate the effects of the case-control sampling scheme on GWAS results based on some standard statistical methods, such as linear regression methods, while comparing it with several advanced statistical methods that appropriately adjust for the case-control sampling scheme. Copyright © 2016 Elsevier Inc. All rights reserved.

Assessment of On-site sanitation system on local groundwater regime in an alluvial aquifer

NASA Astrophysics Data System (ADS)

Quamar, Rafat; Jangam, C.; Veligeti, J.; Chintalapudi, P.; Janipella, R.

2017-12-01

The present study is an attempt to study the impact of the On-site sanitation system on the groundwater sources in its vicinity. The study has been undertaken in the Agra city of Yamuna sub-basin. In this context, sampling sites (3 nos) namely Pandav Nagar, Ayodhya Kunj and Laxmi Nagar were selected for sampling. The groundwater samples were analyzed for major cations, anions and faecal coliform. Critical parameters namely chloride, nitrate and Faecal coliform were considered to assess the impact of the On-site sanitation systems. The analytical results shown that except for chloride, most of the samples exceeded the Bureau of Indian Standard limits for drinking water for all the other analyzed parameters, i.e., nitrate and faecal coliform in the first two sites. In Laxmi Nagar, except for faecal coliform, all the samples are below the BIS limits. In all the three sites, faecal coliform was found in majority of the samples. A comparison of present study indicates that the contamination of groundwater in alluvial setting is less as compared to hard rock where On-site sanitation systems have been implemented.

Does Self-Selection Affect Samples’ Representativeness in Online Surveys? An Investigation in Online Video Game Research

PubMed Central

van Singer, Mathias; Chatton, Anne; Achab, Sophia; Zullino, Daniele; Rothen, Stephane; Khan, Riaz; Billieux, Joel; Thorens, Gabriel

2014-01-01

Background The number of medical studies performed through online surveys has increased dramatically in recent years. Despite their numerous advantages (eg, sample size, facilitated access to individuals presenting stigmatizing issues), selection bias may exist in online surveys. However, evidence on the representativeness of self-selected samples in online studies is patchy. Objective Our objective was to explore the representativeness of a self-selected sample of online gamers using online players’ virtual characters (avatars). Methods All avatars belonged to individuals playing World of Warcraft (WoW), currently the most widely used online game. Avatars’ characteristics were defined using various games’ scores, reported on the WoW’s official website, and two self-selected samples from previous studies were compared with a randomly selected sample of avatars. Results We used scores linked to 1240 avatars (762 from the self-selected samples and 478 from the random sample). The two self-selected samples of avatars had higher scores on most of the assessed variables (except for guild membership and exploration). Furthermore, some guilds were overrepresented in the self-selected samples. Conclusions Our results suggest that more proficient players or players more involved in the game may be more likely to participate in online surveys. Caution is needed in the interpretation of studies based on online surveys that used a self-selection recruitment procedure. Epidemiological evidence on the reduced representativeness of sample of online surveys is warranted. PMID:25001007

Recruiting and enrolling pregnant adolescents for research.

PubMed

Kaiser, Margaret M; Hays, Bevely J

2006-01-01

Difficulty obtaining a sample is not justification for failure to study a hard-to-enroll population, particularly a vulnerable population such as pregnant adolescents. Recruitment of a representative, adequate sample of pregnant adolescents for a recent instrument development study provided multiple challenges. Although carefully developed, the sampling plan required several modifications to achieve the sample (n=145). Those challenges and the ensuing modifications to the sampling plan are discussed in relation to (a) access/institutional concerns, (b) the human subject's protection considerations, and (c) developmental/personal concerns of the pregnant adolescents. Recommendations for sampling strategies for future research are offered.

Lessons Learned for the Assessment of Children’s Pesticide Exposure: Critical Sampling and Analytical Issues for Future Studies

PubMed Central

Fenske, Richard A.; Bradman, Asa; Whyatt, Robin M.; Wolff, Mary S.; Barr, Dana B.

2005-01-01

In this article we examine sampling strategies and analytical methods used in a series of recent studies of children’s exposure to pesticides that may prove useful in the design and implementation of the National Children’s Study. We focus primarily on the experiences of four of the National Institute of Environmental Health Sciences/U.S. Environmental Protection Agency/ Children’s Centers and include University of Washington studies that predated these centers. These studies have measured maternal exposures, perinatal exposures, infant and toddler exposures, and exposure among young children through biologic monitoring, personal sampling, and environmental monitoring. Biologic monitoring appears to be the best available method for assessment of children’s exposure to pesticides, with some limitations. It is likely that a combination of biomarkers, environmental measurements, and questionnaires will be needed after careful consideration of the specific hypotheses posed by investigators and the limitations of each exposure metric. The value of environmental measurements, such as surface and toy wipes and indoor air or house dust samples, deserves further investigation. Emphasis on personal rather than environmental sampling in conjunction with urine or blood sampling is likely to be most effective at classifying exposure. For infants and young children, ease of urine collection (possible for extended periods of time) may make these samples the best available approach to capturing exposure variability of nonpersistent pesticides; additional validation studies are needed. Saliva measurements of pesticides, if feasible, would overcome the limitations of urinary metabolite-based exposure analysis. Global positioning system technology appears promising in the delineation of children’s time–location patterns. PMID:16203262

Statistical inferences for data from studies conducted with an aggregated multivariate outcome-dependent sample design

PubMed Central

Lu, Tsui-Shan; Longnecker, Matthew P.; Zhou, Haibo

2016-01-01

Outcome-dependent sampling (ODS) scheme is a cost-effective sampling scheme where one observes the exposure with a probability that depends on the outcome. The well-known such design is the case-control design for binary response, the case-cohort design for the failure time data and the general ODS design for a continuous response. While substantial work has been done for the univariate response case, statistical inference and design for the ODS with multivariate cases remain under-developed. Motivated by the need in biological studies for taking the advantage of the available responses for subjects in a cluster, we propose a multivariate outcome dependent sampling (Multivariate-ODS) design that is based on a general selection of the continuous responses within a cluster. The proposed inference procedure for the Multivariate-ODS design is semiparametric where all the underlying distributions of covariates are modeled nonparametrically using the empirical likelihood methods. We show that the proposed estimator is consistent and developed the asymptotically normality properties. Simulation studies show that the proposed estimator is more efficient than the estimator obtained using only the simple-random-sample portion of the Multivariate-ODS or the estimator from a simple random sample with the same sample size. The Multivariate-ODS design together with the proposed estimator provides an approach to further improve study efficiency for a given fixed study budget. We illustrate the proposed design and estimator with an analysis of association of PCB exposure to hearing loss in children born to the Collaborative Perinatal Study. PMID:27966260

Africa was still far south in the Late Ypresian: Paleomagnetic study on the early Eocene 'Minia' formation in central Egypt

NASA Astrophysics Data System (ADS)

Lotfy, H.; Heleika, M. Abu; Mostafa, R.; Wahbah, D.

2017-12-01

The paleomagnetic study was carried out on three sections of the Late Ypresian "Minia" formation limestone, in order to shed light on the paleolatitude of northeast Africa upon the end of the Early Eocene. The initial study on the anisotropy of magnetic susceptibility [AMS] helped in confining the paleomagnetic sampling to the virtually isotropic limestone beds. The subsequent stepwise thermal demagnetization of the three-axis isothermal remanence acquired in one sample of each sampled site, revealed the limited contribution of goethite and hematite with the main remanence carrier magnetite in most samples.

Water-quality assessment of part of the upper Mississippi River basin, Minnesota and Wisconsin: Design and implementation of water-quality studies, 1995-98

USGS Publications Warehouse

Stark, James R.; Fallon, J.D.; Fong, A.L.; Goldstein, R.M.; Hanson, P.E.; Kroening, S.E.; Lee, K.E.

1999-01-01

This report describes the design, site-selection, and implementation of the study. Methods used to collect, process, and analyze samples; characterize sites; and assess habitat are described. A comprehensive list of sample sites is provided. Sample analyses for water-quality studies included chlorophyll a, major inorganic constituents, nutrients, trace elements, tritium, radon, environmental isotopes, organic carbon, pesticides, volatile organic compounds, and other synthetic and naturallyoccurring organic compounds. Aquatic-biological samples included fish, benthic macroinvertebrates, and algal enumeration and identification, as well as synthetic-organic compounds and trace elements in fish tissue.

Analytical study of comet nucleus samples

NASA Technical Reports Server (NTRS)

Albee, A. L.

1989-01-01

Analytical procedures for studying and handling frozen (130 K) core samples of comet nuclei are discussed. These methods include neutron activation analysis, x ray fluorescent analysis and high resolution mass spectroscopy.

THE NATIONAL CHILDREN'S STUDY: BEGINNING THE IMPLEMENTATION OF A NATIONAL-PROBABILITY SAMPLE

EPA Science Inventory

Introduction: The National Children's Study (NCS) is a longitudinal cohort study that will follow a sample of approximately 100,000 children born in the United States from before birth until 21 years of age. The NCS will investigate the separate and combined effects of environmen...

IDENTIFYING A POPULATION-BASED SAMPLE OF WOMEN OF REPRODUCTIVE AGE FOR ENVIRONMENTAL STUDIES USING A COMMERCIAL TELEPHONE DIRECTORY

EPA Science Inventory

Environmental studies examining reproductive endpoints such as spontaneous abortion or fertility often rely on very select study groups (i.e., convenience samples, highly exposed, etc.) that cannot be easily generalized to the overall population. For exposures limited to a parti...

Academic Self-Efficacy Perceptions of Teacher Candidates

ERIC Educational Resources Information Center

Yesilyurt, Etem

2013-01-01

This study aims determining academic self-efficacy perception of teacher candidates. It is survey model. Population of the study consists of teacher candidates in 2010-2011 academic years at Ahmet Kelesoglu Education Faculty of Education Formation of Selcuk University. A simple random sample was selected as sampling method and the study was…

Three Conceptual Replication Studies in Group Theory

ERIC Educational Resources Information Center

Melhuish, Kathleen

2018-01-01

Many studies in mathematics education research occur with a nonrepresentative sample and are never replicated. To challenge this paradigm, I designed a large-scale study evaluating student conceptions in group theory that surveyed a national, representative sample of students. By replicating questions previously used to build theory around student…

Advancing ecological understandings through technological transformations in noninvasive genetics

Treesearch

Albano Beja-Pereira; Rita Oliveira; Paulo C. Alves; Michael K. Schwartz; Gordon Luikart

2009-01-01

Noninvasive genetic approaches continue to improve studies in molecular ecology, conservation genetics and related disciplines such as forensics and epidemiology. Noninvasive sampling allows genetic studies without disturbing or even seeing the target individuals. Although noninvasive genetic sampling has been used for wildlife studies since the 1990s, technological...

Appearance Investment and Everyday Interpersonal Functioning: An Experience Sampling Study

ERIC Educational Resources Information Center

Forand, Nicholas R.; Gunthert, Kathleen C.; German, Ramaris E.; Wenze, Susan J.

2010-01-01

Several studies have shown that body satisfaction affects interpersonal functioning. However, few have studied the specific interpersonal correlates of another important body image dimension, appearance investment--that is, the importance a woman places on appearance. We used an experience sampling design with PDA (personal digital assistant)…

Management Philosophies of Primary School Principals

ERIC Educational Resources Information Center

Tas, Said

2011-01-01

The study aimed to determine the management philosophies of primary school principals. Stratification method of sampling was used in the study. The study sample consisted of 33 school principals and 132 teachers serving at primary education schools in Isparta in the academic year 2008-2009. The "Manager Philosophy Scale" developed by Tanriogen and…

Prevalence and types of preanalytical error in hematology laboratory of a tertiary care hospital in South India.

PubMed

Arul, Pitchaikaran; Pushparaj, Magesh; Pandian, Kanmani; Chennimalai, Lingasamy; Rajendran, Karthika; Selvaraj, Eniya; Masilamani, Suresh

2018-01-01

An important component of laboratory medicine is preanalytical phase. Since laboratory report plays a major role in patient management, more importance should be given to the quality of laboratory tests. The present study was undertaken to find the prevalence and types of preanalytical errors at a tertiary care hospital in South India. In this cross-sectional study, a total of 118,732 samples ([62,474 outpatient department [OPD] and 56,258 inpatient department [IPD]) were received in hematology laboratory. These samples were analyzed for preanalytical errors such as misidentification, incorrect vials, inadequate samples, clotted samples, diluted samples, and hemolyzed samples. The overall prevalence of preanalytical errors found was 513 samples, which is 0.43% of the total number of samples received. The most common preanalytical error observed was inadequate samples followed by clotted samples. Overall frequencies (both OPD and IPD) of preanalytical errors such as misidentification, incorrect vials, inadequate samples, clotted samples, diluted samples, and hemolyzed samples were 0.02%, 0.05%, 0.2%, 0.12%, 0.02%, and 0.03%, respectively. The present study concluded that incorrect phlebotomy techniques due to lack of awareness is the main reason for preanalytical errors. This can be avoided by proper communication and coordination between laboratory and wards, proper training and continuing medical education programs for laboratory and paramedical staffs, and knowledge of the intervening factors that can influence laboratory results.

Grays Harbor and Chehalis River Improvements to Navigation Environmental Studies. Grays Harbor Ocean Disposal Study. Literature Review and Preliminary Benthic Sampling,

DTIC Science & Technology

1980-05-01

transects extending approximately 16 kilometers from the mouth of Grays Harbor. Sub- samples were taken for grain size analysis and wood content. The...samples were thert was".d on a 1.0 mm screen to separate benthic organisms from non-living materials. Consideration of the grain size analysis ...Nutrients 17 B. Field Study 18 Methods 18 Grain Size Analysis 18 Wood Analysis 21 Wood Fragments 21 Sediment Types 21 Discussion 24 IV. BIOLOGICAL

Metabolomics: A Window for Understanding Long Term Physical Consequences of Distrubed Sleep and Hypothalamic Pituitary Adrenal Function in Posttraumatic Stress

DTIC Science & Technology

2017-09-01

performed on pre -collected plasma samples from a study that had a two- group cross-sectional design in which main comparisons were with medically...controls. Approach Metabolomic analysis will be performed on pre -collected plasma samples from a study that had a two- group cross-sectional design in...disturbances, and health. Metabolomic analysis will be performed on pre -collected plasma samples from a study that had a two- group cross-sectional

A Feasibility Study of the Collection of Unscheduled Maintenance Data Using Statistical Sampling Techniques.

DTIC Science & Technology

1985-09-01

TECHNIQUES THESIS Robert A. Heinlein Captain, USAF AFIT/GLM/LSM/855-32.- _ DTIC MU’noN ’ST.,TEMENT A A-ZELECTE Approved lt public teleo*I Al \\ Z #&N0V21...343" A FEASIBILITY STUDY OF THE COLLECTION OF UNSCHEDULED MAINTENANCE DATA USING STrATISTICAL SAMPLING TECHNIQUES THESIS L .9 Robe-t A. Heinlein...a AFIT/GLM/LSM/85S-32 A FEASIBILITY STUDY OF THE COLLECTION OF UNSCHEDULED MAINTENANCE DATA USING STATISTICAL SAMPLING TECHNIQUES THESIS

Procedures for Handling and Chemical Analysis of Sediment and Water Samples,

DTIC Science & Technology

1981-05-01

silts. Particularly suitable for studies of the sediment/ water interface, for studies on depositonal sediment structures. Al pi ne- ravity Cores of 2 m...adverse water quality impacts would occur. Elemental partitioning or sedimentation fractionation studies are the most complex of the tests considered...8217 water %nd blend the core or dredge sample. Place a{js roximalel-i 00 cc of’ the blended sample in an oxygen-free, poly - ca rbor’~ [ ’-l centrifuge bottle

A Psychometric Study of the Fear of Sleep Inventory-Short Form (FoSI-SF)

PubMed Central

Pruiksma, Kristi E.; Taylor, Daniel J.; Ruggero, Camilo; Boals, Adriel; Davis, Joanne L.; Cranston, Christopher; DeViva, Jason C.; Zayfert, Claudia

2014-01-01

Study Objectives: Fear of sleep may play a significant role in sleep disturbances in individuals with posttraumatic stress disorder (PTSD). This report describes a psychometric study of the Fear of Sleep Inventory (FoSI), which was developed to measure this construct. Methods: The psychometric properties of the FoSI were examined in a non-clinical sample of 292 college students (Study I) and in a clinical sample of 67 trauma-exposed adults experiencing chronic nightmares (Study II). Data on the 23 items of the FoSI were subjected to exploratory factor analyses (EFA) to identify items uniquely assessing fear of sleep. Next, reliability and validity of a 13-item version of the FoSI was examined in both samples. Results: A 13-item Short-Form version (FoSI-SF) was identified as having a clear 2-factor structure with high internal consistency in both the non-clinical (α = 0.76–0.94) and clinical (α = 0.88-0.91) samples. Both studies demonstrated good convergent validity with measures of PTSD (0.48-0.61) and insomnia (0.39-0.48) and discriminant validity with a measure of sleep hygiene (0.19-0.27). The total score on the FoSI-SF was significantly higher in the clinical sample (mean = 17.90, SD = 12.56) than in the non-clinical sample (mean = 4.80, SD = 7.72); t357 = 8.85 p < 0.001. Conclusions: Although all items are recommended for clinical purposes, the data support the use of the 13-item FoSI-SF for research purposes. Replication of the factor structure in clinical samples is needed. Results are discussed in terms of limitations of this study and directions for further research. Citation: Pruiksma KE, Taylor DJ, Ruggero C, Boals A, Davis JL, Cranston C, DeViva JC, Zayfert C. A psychometric study of the Fear of Sleep Inventory-short form (FoSI-SF). J Clin Sleep Med 2014;10(5):551-558. PMID:24812541

Sampling for pharmaceuticals and personal care products (PPCPs) and illicit drugs in wastewater systems: are your conclusions valid? A critical review.

PubMed

Ort, Christoph; Lawrence, Michael G; Rieckermann, Jörg; Joss, Adriano

2010-08-15

The analysis of 87 peer-reviewed journal articles reveals that sampling for pharmaceuticals and personal care products (PPCPs) and illicit drugs in sewers and sewage treatment plant influents is mostly carried out according to existing tradition or standard laboratory protocols. Less than 5% of all studies explicitly consider internationally acknowledged guidelines or methods for the experimental design of monitoring campaigns. In the absence of a proper analysis of the system under investigation, the importance of short-term pollutant variations was typically not addressed. Therefore, due to relatively long sampling intervals, potentially inadequate sampling modes, or insufficient documentation, it remains unclear for the majority of reviewed studies whether observed variations can be attributed to "real" variations or if they simply reflect sampling artifacts. Based on results from previous and current work, the present paper demonstrates that sampling errors can lead to overinterpretation of measured data and ultimately, wrong conclusions. Depending on catchment size, sewer type, sampling setup, substance of interest, and accuracy of analytical method, avoidable sampling artifacts can range from "not significant" to "100% or more" for different compounds even within the same study. However, in most situations sampling errors can be reduced greatly, and sampling biases can be eliminated completely, by choosing an appropriate sampling mode and frequency. This is crucial, because proper sampling will help to maximize the value of measured data for the experimental assessment of the fate of PPCPs as well as for the formulation and validation of mathematical models. The trend from reporting presence or absence of a compound in "clean" water samples toward the quantification of PPCPs in raw wastewater requires not only sophisticated analytical methods but also adapted sampling methods. With increasing accuracy of chemical analyses, inappropriate sampling increasingly represents the major source of inaccuracy. A condensed step-by-step Sampling Guide is proposed as a starting point for future studies.

Enhancing sampling design in mist-net bat surveys by accounting for sample size optimization.

PubMed

Trevelin, Leonardo Carreira; Novaes, Roberto Leonan Morim; Colas-Rosas, Paul François; Benathar, Thayse Cristhina Melo; Peres, Carlos A

2017-01-01

The advantages of mist-netting, the main technique used in Neotropical bat community studies to date, include logistical implementation, standardization and sampling representativeness. Nonetheless, study designs still have to deal with issues of detectability related to how different species behave and use the environment. Yet there is considerable sampling heterogeneity across available studies in the literature. Here, we approach the problem of sample size optimization. We evaluated the common sense hypothesis that the first six hours comprise the period of peak night activity for several species, thereby resulting in a representative sample for the whole night. To this end, we combined re-sampling techniques, species accumulation curves, threshold analysis, and community concordance of species compositional data, and applied them to datasets of three different Neotropical biomes (Amazonia, Atlantic Forest and Cerrado). We show that the strategy of restricting sampling to only six hours of the night frequently results in incomplete sampling representation of the entire bat community investigated. From a quantitative standpoint, results corroborated the existence of a major Sample Area effect in all datasets, although for the Amazonia dataset the six-hour strategy was significantly less species-rich after extrapolation, and for the Cerrado dataset it was more efficient. From the qualitative standpoint, however, results demonstrated that, for all three datasets, the identity of species that are effectively sampled will be inherently impacted by choices of sub-sampling schedule. We also propose an alternative six-hour sampling strategy (at the beginning and the end of a sample night) which performed better when resampling Amazonian and Atlantic Forest datasets on bat assemblages. Given the observed magnitude of our results, we propose that sample representativeness has to be carefully weighed against study objectives, and recommend that the trade-off between logistical constraints and additional sampling performance should be carefully evaluated.

Enhancing sampling design in mist-net bat surveys by accounting for sample size optimization

PubMed Central

Trevelin, Leonardo Carreira; Novaes, Roberto Leonan Morim; Colas-Rosas, Paul François; Benathar, Thayse Cristhina Melo; Peres, Carlos A.

2017-01-01

The advantages of mist-netting, the main technique used in Neotropical bat community studies to date, include logistical implementation, standardization and sampling representativeness. Nonetheless, study designs still have to deal with issues of detectability related to how different species behave and use the environment. Yet there is considerable sampling heterogeneity across available studies in the literature. Here, we approach the problem of sample size optimization. We evaluated the common sense hypothesis that the first six hours comprise the period of peak night activity for several species, thereby resulting in a representative sample for the whole night. To this end, we combined re-sampling techniques, species accumulation curves, threshold analysis, and community concordance of species compositional data, and applied them to datasets of three different Neotropical biomes (Amazonia, Atlantic Forest and Cerrado). We show that the strategy of restricting sampling to only six hours of the night frequently results in incomplete sampling representation of the entire bat community investigated. From a quantitative standpoint, results corroborated the existence of a major Sample Area effect in all datasets, although for the Amazonia dataset the six-hour strategy was significantly less species-rich after extrapolation, and for the Cerrado dataset it was more efficient. From the qualitative standpoint, however, results demonstrated that, for all three datasets, the identity of species that are effectively sampled will be inherently impacted by choices of sub-sampling schedule. We also propose an alternative six-hour sampling strategy (at the beginning and the end of a sample night) which performed better when resampling Amazonian and Atlantic Forest datasets on bat assemblages. Given the observed magnitude of our results, we propose that sample representativeness has to be carefully weighed against study objectives, and recommend that the trade-off between logistical constraints and additional sampling performance should be carefully evaluated. PMID:28334046

Correcting for the influence of sampling conditions on biomarkers of exposure to phenols and phthalates: a 2-step standardization method based on regression residuals.

PubMed

Mortamais, Marion; Chevrier, Cécile; Philippat, Claire; Petit, Claire; Calafat, Antonia M; Ye, Xiaoyun; Silva, Manori J; Brambilla, Christian; Eijkemans, Marinus J C; Charles, Marie-Aline; Cordier, Sylvaine; Slama, Rémy

2012-04-26

Environmental epidemiology and biomonitoring studies typically rely on biological samples to assay the concentration of non-persistent exposure biomarkers. Between-participant variations in sampling conditions of these biological samples constitute a potential source of exposure misclassification. Few studies attempted to correct biomarker levels for this error. We aimed to assess the influence of sampling conditions on concentrations of urinary biomarkers of select phenols and phthalates, two widely-produced families of chemicals, and to standardize biomarker concentrations on sampling conditions. Urine samples were collected between 2002 and 2006 among 287 pregnant women from Eden and Pélagie cohorts, from which phthalates and phenols metabolites levels were assayed. We applied a 2-step standardization method based on regression residuals. First, the influence of sampling conditions (including sampling hour, duration of storage before freezing) and of creatinine levels on biomarker concentrations were characterized using adjusted linear regression models. In the second step, the model estimates were used to remove the variability in biomarker concentrations due to sampling conditions and to standardize concentrations as if all samples had been collected under the same conditions (e.g., same hour of urine collection). Sampling hour was associated with concentrations of several exposure biomarkers. After standardization for sampling conditions, median concentrations differed by--38% for 2,5-dichlorophenol to +80 % for a metabolite of diisodecyl phthalate. However, at the individual level, standardized biomarker levels were strongly correlated (correlation coefficients above 0.80) with unstandardized measures. Sampling conditions, such as sampling hour, should be systematically collected in biomarker-based studies, in particular when the biomarker half-life is short. The 2-step standardization method based on regression residuals that we proposed in order to limit the impact of heterogeneity in sampling conditions could be further tested in studies describing levels of biomarkers or their influence on health.

Chemistry and origin of minor and trace elements in selected vitrinite concentrates from bituminous and anthracitic coals

USGS Publications Warehouse

Palmer, C.A.; Lyons, P.C.

1990-01-01

Twelve hand-picked vitrinite concentrates and companion whole-coal samples were analyzed for trace and minor elements by instrumental neutron activation analysis (INAA) and direct-current-arc spectrographic techniques (DCAS). The vitrinite concentrates contained 94 to nearly 100 vol.% vitrinite compared to 71-95 vol.% in the companion whole coals. The ash contents of the vitrinite concentrates were 2 to more than 190 times less than the ash contents of the companion whole coals. Organic and inorganic affinities were determined by comparing the elemental concentrations in the vitrinite concentrates to the concentrations in the companion whole coals. The ratios of these concentrations for 33 selected elements are shown in Figure 1. Ratios greater than 1 indicate organic affinity, and ratios less than 1 indicate inorganic affinity. Br and W generally showed organic affinity in all samples in this study. In the nine samples from the eastern United States (Fig. 1A-C) less than one-fourth of the trace elements show organic affinity compared to nearly one-half for the three English and Australian samples (Fig. 1D). The elements that generally show organic affinity in the non-U.S.A. samples studied include As, Cs, Hf, and Ni, which have generally inorganic affinities in the U.S.A. samples, and Cr, Sb, Se, and U, which have mixed (both organic and inorganic) affinities, in the U.S.A. coals studied, has an inorganic affinity in the English coals studied. B shows organic affinity in the samples from the Illinois basin (Fig. 1C). For the samples studied, Ba shows organic affinity in the Appalachian basin bituminous coals (Fig. 1B), inorganic affinity in the Illinois basin coals, and overall mixed affinities. In all the samples studied, Cu, Mn, Na, Sr, Ta, V, and Zn show mixed affinities, and A1, Co, Eu, Fe, Ga, K, La, Mg, Sc, Si, Th, Ti, and Ub have generally inorganic affinity. ?? 1990.

The importance of sampling standardization for comparisons of insect herbivory in deep time: a case study from the late Palaeozoic

NASA Astrophysics Data System (ADS)

Schachat, Sandra R.; Labandeira, Conrad C.; Maccracken, S. Augusta

2018-03-01

Sampling standardization has not been fully addressed for the study of insect herbivory in the fossil record. The effects of sampling within a single locality were explored almost a decade ago, but the importance of sampling standardization for comparisons of herbivory across space and time has not yet been evaluated. Here, we present a case study from the Permian in which we evaluate the impact of sampling standardization on comparisons of insect herbivory from two localities that are similar in age and floral composition. Comparisons of insect damage type (DT) diversity change dramatically when the number of leaves examined is standardized by surface area. This finding suggests that surface area should always be taken into account for comparisons of DT diversity. In addition, the three most common metrics of herbivory-DT diversity, proportion of leaves herbivorized and proportion of leaf surface area herbivorized-are inherently decoupled from each other. The decoupling of the diversity and intensity of insect herbivory necessitates a reinterpretation of published data because they had been conflated in previous studies. Future studies should examine the divergent ecological factors that underlie these metrics. We conclude with suggestions to guide the sampling and analysis of herbivorized leaves in the fossil record.

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

PubMed

Thomas, Elaine

2005-01-01

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

Geochemical data for stream-sediment, heavy-mineral-concentrate and rock samples collected from the Fortyseven Creek gold-arsenic-antimony-tungsten prospect, southwestern Alaska

USGS Publications Warehouse

Gray, John E.; Lee, G.K.; O'Leary, R. M.; Theodorakos, P.M.

1999-01-01

In the summer of 1991, we conducted a reconnaissance geochemical survey around the Fortyseven Creek Au-As-Sb-W prospect that is located in the southwestern part of the Sleetmute quadrangle. At that time, this project was a small part of a more comprehensive Alaska Mineral Resource Assessment Program (AMRAP) study of the Sleemute quadrangle. AMRAP studies were conducted by the U.S. Geological Survey (USGS) to fulfill requirements of the Alaska National Interests Lands Conservation Act (Public Law 96-487, 1980) to survey certain federal lands to determine their mineral potential. Although AMRAP is no longer in operation, this study represents a small topical study that was conducted during the Sleetmute quadrangle AMRAP study. The objective of the Fortyseven Creek work was to characterize the geochemistry of samples collected downstream from the Fortyseven Creek prospect, as well as mineralized and altered rock samples collected from the prospect. In this report, we describe the samples collected in 1991, the methods used for the analysis of the samples, and the geochemical data for these samples. The data in this report are also available in digital form on computer diskette in Gray and others (1999). An interpretation of these data appears in Gray and others (1998).

The Sample for the Sustaining Effects Study and Projections of its Characteristic to the National Population. Technical Report No. 1 from the Study of Sustaining Effects of Compensatory Education on Basic Skills.

ERIC Educational Resources Information Center

Hoepfner, Ralph; And Others

Sampling techniques used in "A Study of the Sustaining Effects of Compensatory Education" are described in detail. The Sustaining Effects Study is a large, multi-faceted study of issues related to the compensatory education of elementary school students. Public elementary schools that include grades between one and six are eligible for…

Stress, Geomagnetic Disturbance, Infradian and Circadian Sampling for Circulating Corticosterone and Models of Human Depression?

PubMed Central

Olah, A.; Jozsa, R.; Csernus, V.; Sandor, J.; Muller, A.; Zeman, M.; Hoogerwerf, W.; Cornélissen, G.; Halberg, F.

2008-01-01

While certain circadian hormonal changes are prominent, their predictable assessment requires a standardization of conditions of sampling. The 24-hour rhythm in circulating corticosterone of rodents, known since the 1950s, was studied as a presumed proxy for stress on 108 rats divided into 9 groups of 6 male and 9 groups of 6 female animals sampled every 4 hours for 24 hours. In a first stress study, the “no-rhythm” (zero-amplitude) assumption failed to be rejected at the 5% probability level in the two control groups and in 16 out of the 18 groups considered. A circadian rhythm could be detected with statistical significance, however, in three separate follow-up studies in the same laboratory, each on 168 rats kept on two antiphasic lighting regimens, with 4-hourly sampling for 7 or 14 days. In the first stress study, pooling of certain groups helped the detection and assessment of the circadian corticosterone rhythm. Without extrapolating to hormones other than corticosterone, which may shift more slowly or adjust differently and in response to different synchronizers, the three follow-up studies yielded uncertainty measures (95% confidence intervals) for the point estimate of its circadian period, of possible use in any future study as a reference standard. The happenstance of a magnetic disturbance at the start of two follow-up studies was associated with the detection of a circasemiseptan component, raising the question whether a geomagnetic disturbance could be considered as a “load”. Far beyond the limitations of sample size, the methodological requirements for standardization in the experimental laboratory concerning designs of studies are considered in the context of models of depression. Lessons from nature's unforeseen geomagnetic contribution and from human studies are noted, all to support the advocacy, in the study of loads, of sampling schedules covering more than 24 hours. PMID:18515211

Optimal design in pediatric pharmacokinetic and pharmacodynamic clinical studies.

PubMed

Roberts, Jessica K; Stockmann, Chris; Balch, Alfred; Yu, Tian; Ward, Robert M; Spigarelli, Michael G; Sherwin, Catherine M T

2015-03-01

It is not trivial to conduct clinical trials with pediatric participants. Ethical, logistical, and financial considerations add to the complexity of pediatric studies. Optimal design theory allows investigators the opportunity to apply mathematical optimization algorithms to define how to structure their data collection to answer focused research questions. These techniques can be used to determine an optimal sample size, optimal sample times, and the number of samples required for pharmacokinetic and pharmacodynamic studies. The aim of this review is to demonstrate how to determine optimal sample size, optimal sample times, and the number of samples required from each patient by presenting specific examples using optimal design tools. Additionally, this review aims to discuss the relative usefulness of sparse vs rich data. This review is intended to educate the clinician, as well as the basic research scientist, whom plan on conducting a pharmacokinetic/pharmacodynamic clinical trial in pediatric patients. © 2015 John Wiley & Sons Ltd.

Challenges in collecting clinical samples for research from pregnant women of South Asian origin: evidence from a UK study.

PubMed

Neelotpol, Sharmind; Hay, Alastair W M; Jolly, A Jim; Woolridge, Mike W

2016-08-31

To recruit South Asian pregnant women, living in the UK, into a clinicoepidemiological study for the collection of lifestyle survey data and antenatal blood and to retain the women for the later collection of cord blood and meconium samples from their babies for biochemical analysis. A longitudinal study recruiting pregnant women of South Asian and Caucasian origin living in the UK. Recruitment of the participants, collection of clinical samples and survey data took place at the 2 sites within a single UK Northern Hospital Trust. Pregnant women of South Asian origin (study group, n=98) and of Caucasian origin (comparison group, n=38) living in Leeds, UK. Among the participants approached, 81% agreed to take part in the study while a 'direct approach' method was followed. The retention rate of the participants was a remarkable 93.4%. The main challenges in recruiting the ethnic minority participants were their cultural and religious conservativeness, language barrier, lack of interest and feeling of extra 'stress' in taking part in research. The chief investigator developed an innovative participant retention method, associated with the women's cultural and religious practices. The method proved useful in retaining the participants for about 5 months and in enabling successful collection of clinical samples from the same mother-baby pairs. The collection of clinical samples and lifestyle data exceeded the calculated sample size required to give the study sufficient power. The numbers of samples obtained were: maternal blood (n=171), cord blood (n=38), meconium (n=176), lifestyle questionnaire data (n=136) and postnatal records (n=136). Recruitment and retention of participants, according to the calculated sample size, ensured sufficient power and success for a clinicoepidemiological study. Results suggest that development of trust and confidence between the participant and the researcher is the key to the success of a clinical and epidemiological study involving ethnic minorities. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Sampling challenges in a study examining refugee resettlement

PubMed Central

2011-01-01

Background As almost half of all refugees currently under United Nations protection are from Afghanistan or Iraq and significant numbers have already been resettled outside the region of origin, it is likely that future research will examine their resettlement needs. A number of methodological challenges confront researchers working with culturally and linguistically diverse groups; however, few detailed articles are available to inform other studies. The aim of this paper is to outline challenges with sampling and recruitment of socially invisible refugee groups, describing the method adopted for a mixed methods exploratory study assessing mental health, subjective wellbeing and resettlement perspectives of Afghan and Kurdish refugees living in New Zealand and Australia. Sampling strategies used in previous studies with similar refugee groups were considered before determining the approach to recruitment Methods A snowball approach was adopted for the study, with multiple entry points into the communities being used to choose as wide a range of people as possible to provide further contacts and reduce selection bias. Census data was used to assess the representativeness of the sample. Results A sample of 193 former refugee participants was recruited in Christchurch (n = 98) and Perth (n = 95), 47% were of Afghan and 53% Kurdish ethnicity. A good gender balance (males 52%, females 48%) was achieved overall, mainly as a result of the sampling method used. Differences in the demographic composition of groups in each location were observed, especially in relation to the length of time spent in a refugee situation and time since arrival, reflecting variations in national humanitarian quota intakes. Although some measures were problematic, Census data comparison to assess reasonable representativeness of the study sample was generally reassuring. Conclusions Snowball sampling, with multiple initiation points to reduce selection bias, was necessary to locate and identify participants, provide reassurance and break down barriers. Personal contact was critical for both recruitment and data quality, and highlighted the importance of interviewer cultural sensitivity. Cross-national comparative studies, particularly relating to refugee resettlement within different policy environments, also need to take into consideration the differing pre-migration experiences and time since arrival of refugee groups, as these can add additional layers of complexity to study design and interpretation. PMID:21406104

Sampling challenges in a study examining refugee resettlement.

PubMed

Sulaiman-Hill, Cheryl Mr; Thompson, Sandra C

2011-03-15

As almost half of all refugees currently under United Nations protection are from Afghanistan or Iraq and significant numbers have already been resettled outside the region of origin, it is likely that future research will examine their resettlement needs. A number of methodological challenges confront researchers working with culturally and linguistically diverse groups; however, few detailed articles are available to inform other studies. The aim of this paper is to outline challenges with sampling and recruitment of socially invisible refugee groups, describing the method adopted for a mixed methods exploratory study assessing mental health, subjective wellbeing and resettlement perspectives of Afghan and Kurdish refugees living in New Zealand and Australia. Sampling strategies used in previous studies with similar refugee groups were considered before determining the approach to recruitment A snowball approach was adopted for the study, with multiple entry points into the communities being used to choose as wide a range of people as possible to provide further contacts and reduce selection bias. Census data was used to assess the representativeness of the sample. A sample of 193 former refugee participants was recruited in Christchurch (n = 98) and Perth (n = 95), 47% were of Afghan and 53% Kurdish ethnicity. A good gender balance (males 52%, females 48%) was achieved overall, mainly as a result of the sampling method used. Differences in the demographic composition of groups in each location were observed, especially in relation to the length of time spent in a refugee situation and time since arrival, reflecting variations in national humanitarian quota intakes. Although some measures were problematic, Census data comparison to assess reasonable representativeness of the study sample was generally reassuring. Snowball sampling, with multiple initiation points to reduce selection bias, was necessary to locate and identify participants, provide reassurance and break down barriers. Personal contact was critical for both recruitment and data quality, and highlighted the importance of interviewer cultural sensitivity. Cross-national comparative studies, particularly relating to refugee resettlement within different policy environments, also need to take into consideration the differing pre-migration experiences and time since arrival of refugee groups, as these can add additional layers of complexity to study design and interpretation.

Reproducibility of urinary biomarkers in multiple 24-h urine samples.

PubMed

Sun, Qi; Bertrand, Kimberly A; Franke, Adrian A; Rosner, Bernard; Curhan, Gary C; Willett, Walter C

2017-01-01

Limited knowledge regarding the reproducibility of biomarkers in 24-h urine samples has hindered the collection and use of the samples in epidemiologic studies. We aimed to evaluate the reproducibility of various markers in repeat 24-h urine samples. We calculated intraclass correlation coefficients (ICCs) of biomarkers measured in 24-h urine samples that were collected in 3168 participants in the NHS (Nurses' Health Study), NHSII (Nurses' Health Study II), and Health Professionals Follow-Up Study. In 742 women with 4 samples each collected over the course of 1 y, ICCs for sodium were 0.32 in the NHS and 0.34 in the NHSII. In 2439 men and women with 2 samples each collected over 1 wk to ≥1 mo, the ICCs ranged from 0.33 to 0.68 for sodium at various intervals between collections. The urinary excretion of potassium, calcium, magnesium, phosphate, sulfate, and other urinary markers showed generally higher reproducibility (ICCs >0.4). In 47 women with two 24-h urine samples, ICCs ranged from 0.15 (catechin) to 0.75 (enterolactone) for polyphenol metabolites. For phthalates, ICCs were generally ≤0.26 except for monobenzyl phthalate (ICC: 0.55), whereas the ICC was 0.39 for bisphenol A (BPA). We further estimated that, for the large majority of the biomarkers, the mean of three 24-h urine samples could provide a correlation of ≥0.8 with true long-term urinary excretion. These data suggest that the urinary excretion of various biomarkers, such as minerals, electrolytes, most polyphenols, and BPA, is reasonably reproducible in 24-h urine samples that are collected within a few days or ≤1 y. Our findings show that three 24-h samples are sufficient for the measurement of long-term exposure status in epidemiologic studies. © 2017 American Society for Nutrition.

Reproducibility of urinary biomarkers in multiple 24-h urine samples123

PubMed Central

Sun, Qi; Bertrand, Kimberly A; Franke, Adrian A; Rosner, Bernard; Curhan, Gary C; Willett, Walter C

2017-01-01

Background: Limited knowledge regarding the reproducibility of biomarkers in 24-h urine samples has hindered the collection and use of the samples in epidemiologic studies. Objective: We aimed to evaluate the reproducibility of various markers in repeat 24-h urine samples. Design: We calculated intraclass correlation coefficients (ICCs) of biomarkers measured in 24-h urine samples that were collected in 3168 participants in the NHS (Nurses’ Health Study), NHSII (Nurses’ Health Study II), and Health Professionals Follow-Up Study. Results: In 742 women with 4 samples each collected over the course of 1 y, ICCs for sodium were 0.32 in the NHS and 0.34 in the NHSII. In 2439 men and women with 2 samples each collected over 1 wk to ≥1 mo, the ICCs ranged from 0.33 to 0.68 for sodium at various intervals between collections. The urinary excretion of potassium, calcium, magnesium, phosphate, sulfate, and other urinary markers showed generally higher reproducibility (ICCs >0.4). In 47 women with two 24-h urine samples, ICCs ranged from 0.15 (catechin) to 0.75 (enterolactone) for polyphenol metabolites. For phthalates, ICCs were generally ≤0.26 except for monobenzyl phthalate (ICC: 0.55), whereas the ICC was 0.39 for bisphenol A (BPA). We further estimated that, for the large majority of the biomarkers, the mean of three 24-h urine samples could provide a correlation of ≥0.8 with true long-term urinary excretion. Conclusions: These data suggest that the urinary excretion of various biomarkers, such as minerals, electrolytes, most polyphenols, and BPA, is reasonably reproducible in 24-h urine samples that are collected within a few days or ≤1 y. Our findings show that three 24-h samples are sufficient for the measurement of long-term exposure status in epidemiologic studies. PMID:28049663

Clustering Methods with Qualitative Data: A Mixed Methods Approach for Prevention Research with Small Samples

PubMed Central

Henry, David; Dymnicki, Allison B.; Mohatt, Nathaniel; Allen, James; Kelly, James G.

2016-01-01

Qualitative methods potentially add depth to prevention research, but can produce large amounts of complex data even with small samples. Studies conducted with culturally distinct samples often produce voluminous qualitative data, but may lack sufficient sample sizes for sophisticated quantitative analysis. Currently lacking in mixed methods research are methods allowing for more fully integrating qualitative and quantitative analysis techniques. Cluster analysis can be applied to coded qualitative data to clarify the findings of prevention studies by aiding efforts to reveal such things as the motives of participants for their actions and the reasons behind counterintuitive findings. By clustering groups of participants with similar profiles of codes in a quantitative analysis, cluster analysis can serve as a key component in mixed methods research. This article reports two studies. In the first study, we conduct simulations to test the accuracy of cluster assignment using three different clustering methods with binary data as produced when coding qualitative interviews. Results indicated that hierarchical clustering, K-Means clustering, and latent class analysis produced similar levels of accuracy with binary data, and that the accuracy of these methods did not decrease with samples as small as 50. Whereas the first study explores the feasibility of using common clustering methods with binary data, the second study provides a “real-world” example using data from a qualitative study of community leadership connected with a drug abuse prevention project. We discuss the implications of this approach for conducting prevention research, especially with small samples and culturally distinct communities. PMID:25946969

Water- and air-quality monitoring of the Sweetwater Reservoir Watershed, San Diego County, California-Phase One results, continued, 1999-2001

USGS Publications Warehouse

Mendez, Gregory O.; Foreman, William T.; Sidhu, Jagdeep S.; Majewski, Michael S.

2007-01-01

In 1998, the U.S. Geological Survey, in cooperation with the Sweetwater Authority, began a study to assess the overall health of the Sweetwater watershed with respect to chemical contamination. The study included regular sampling of air and water at Sweetwater Reservoir for chemical contaminants, including volatile organic compounds, polycyclic aromatic hydrocarbons, pesticides, and major and trace elements. Background water samples were collected at Loveland Reservoir for volatile organic compounds and pesticides. The purpose of this study was to monitor changes in contaminant composition and concentration in the air and water resulting from the construction and operation of State Route 125 near Sweetwater Reservoir. To accomplish this, the study was divided into two phases. Phase One sampling was designed to establish baseline conditions for target compounds in terms of detection frequency and concentration in air and water. Phase Two sampling is planned to continue at the established monitoring sites during and after construction of State Route 125 to assess the chemical impact this roadway alignment project may have on the water quality in the reservoir. In addition to the ongoing data collection, several special studies were initiated to assess the occurrence of specific chemicals of concern, such as low-use pesticides, trace metals, and wastewater compounds. This report describes the study design, and the sampling and analytical methods, and presents the results for the second and third years of the study (October 1999 to September 2001). Data collected during the first year of sampling (October 1998 to September 1999) were published in 2002.

Psychometric Properties of the Dutch Depression Stigma Scale (DSS) and Associations with Personal and Perceived Stigma in a Depressed and Community Sample

PubMed Central

Cuijpers, P.; Griffiths, K. M.; Kleiboer, A. M.

2016-01-01

Background Research on depression stigma is needed to gain more insight into the underlying construct and to reduce the level of stigma in the community. However, few validated measurements of depression stigma are available in the Netherlands. Therefore, this study first sought to examine the psychometric properties of the Dutch translation of the Depression Stigma Scale (DSS). Second, we examined which demographic (gender, age, education, partner status) and other variables (anxiety and knowledge of depression) are associated with personal and perceived stigma within these samples. Methods The study population consisted of an adult convenience sample (n = 253) (study 1) and a community adult sample with elevated depressive symptoms (n = 264) (study 2). Factor structure, internal consistency, and validity were assessed. The associations between stigma, demographic variables and anxiety level were examined with regression analyses. Results Confirmatory factor analysis supported the validity and internal consistency of the DSS personal stigma scale. Internal consistency was sufficient (Cronbach’s alpha = .70 (study 1) and .77 (study 2)). The results regarding the perceived stigma scale revealed no clear factor structure. Regression analyses showed that personal stigma was higher in younger people, those with no experience with depression, and those with lower education. Conclusions This study established the validity and internal consistency of the DSS personal scale in the Netherlands, in a community sample and in people with elevated depressive symptoms. However, additional research is needed to examine the factor structure of the DSS perceived scale and its use in other samples. PMID:27500969

Clustering Methods with Qualitative Data: a Mixed-Methods Approach for Prevention Research with Small Samples.

PubMed

Henry, David; Dymnicki, Allison B; Mohatt, Nathaniel; Allen, James; Kelly, James G

2015-10-01

Qualitative methods potentially add depth to prevention research but can produce large amounts of complex data even with small samples. Studies conducted with culturally distinct samples often produce voluminous qualitative data but may lack sufficient sample sizes for sophisticated quantitative analysis. Currently lacking in mixed-methods research are methods allowing for more fully integrating qualitative and quantitative analysis techniques. Cluster analysis can be applied to coded qualitative data to clarify the findings of prevention studies by aiding efforts to reveal such things as the motives of participants for their actions and the reasons behind counterintuitive findings. By clustering groups of participants with similar profiles of codes in a quantitative analysis, cluster analysis can serve as a key component in mixed-methods research. This article reports two studies. In the first study, we conduct simulations to test the accuracy of cluster assignment using three different clustering methods with binary data as produced when coding qualitative interviews. Results indicated that hierarchical clustering, K-means clustering, and latent class analysis produced similar levels of accuracy with binary data and that the accuracy of these methods did not decrease with samples as small as 50. Whereas the first study explores the feasibility of using common clustering methods with binary data, the second study provides a "real-world" example using data from a qualitative study of community leadership connected with a drug abuse prevention project. We discuss the implications of this approach for conducting prevention research, especially with small samples and culturally distinct communities.

MRSA in Conventional and Alternative Retail Pork Products

PubMed Central

O'Brien, Ashley M.; Hanson, Blake M.; Farina, Sarah A.; Wu, James Y.; Simmering, Jacob E.; Wardyn, Shylo E.; Forshey, Brett M.; Kulick, Marie E.; Wallinga, David B.; Smith, Tara C.

2012-01-01

In order to examine the prevalence of Staphylococcus aureus on retail pork, three hundred ninety-five pork samples were collected from a total of 36 stores in Iowa, Minnesota, and New Jersey. S. aureus was isolated from 256 samples (64.8%, 95% confidence interval [CI] 59.9%–69.5%). S. aureus was isolated from 67.3% (202/300) of conventional pork samples and from 56.8% (54/95) of alternative pork samples (labeled “raised without antibiotics” or “raised without antibiotic growth promotants”). Two hundred and thirty samples (58.2%, 95% CI 53.2%–63.1%) were found to carry methicillin-sensitive S. aureus (MSSA). MSSA was isolated from 61.0% (183/300) of conventional samples and from 49.5% (47/95) of alternative samples. Twenty-six pork samples (6.6%, 95% CI 4.3%–9.5%) carried methicillin-resistant S. aureus (MRSA). No statistically significant differences were observed for the prevalence of S. aureus in general, or MSSA or MRSA specifically, when comparing pork products from conventionally raised swine and swine raised without antibiotics, a finding that contrasts with a prior study from the Netherlands examining both conventional and “biologic” meat products. In our study spa types associated with “livestock-associated” ST398 (t034, t011) were found in 26.9% of the MRSA isolates, while 46.2% were spa types t002 and t008—common human types of MRSA that also have been found in live swine. The study represents the largest sampling of raw meat products for MRSA contamination to date in the U.S. MRSA prevalence on pork products was higher than in previous U.S.-conducted studies, although similar to that in Canadian studies. PMID:22276147

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

PubMed

Whitmore, Roy W; Chen, Wenlin

2013-12-04

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

Beyond the "science of sophomores": does the rational choice explanation of crime generalize from university students to an actual offender sample?

PubMed

Bouffard, Jeff; Bry, Jeff; Smith, Shamayne; Bry, Rhonda

2008-12-01

Much of the criminological literature testing rational choice theory has utilized hypothetical scenarios presented to university students. Although this research generally supports rational choice theory, a common criticism is that conclusions from these studies may not generalize to samples of actual offenders. This study proceeds to examine this issue in two steps. First, a traditional sample of university students is examined to determine how various costs and benefits relate to their hypothetical likelihood of offending. Then the same data collection procedures are employed with a somewhat different sample of younger, adjudicated, and institutionalized offenders to determine whether the conclusions drawn from the student sample generalize to this offender sample. Results generally suggest that the content and process of hypothetical criminal decision making differ in the sample of known offenders relative to the university students. Limitations of the current study, as well as suggestions for future research, are discussed.

Scalable multi-sample single-cell data analysis by Partition-Assisted Clustering and Multiple Alignments of Networks

PubMed Central

Samusik, Nikolay; Wang, Xiaowei; Guan, Leying; Nolan, Garry P.

2017-01-01

Mass cytometry (CyTOF) has greatly expanded the capability of cytometry. It is now easy to generate multiple CyTOF samples in a single study, with each sample containing single-cell measurement on 50 markers for more than hundreds of thousands of cells. Current methods do not adequately address the issues concerning combining multiple samples for subpopulation discovery, and these issues can be quickly and dramatically amplified with increasing number of samples. To overcome this limitation, we developed Partition-Assisted Clustering and Multiple Alignments of Networks (PAC-MAN) for the fast automatic identification of cell populations in CyTOF data closely matching that of expert manual-discovery, and for alignments between subpopulations across samples to define dataset-level cellular states. PAC-MAN is computationally efficient, allowing the management of very large CyTOF datasets, which are increasingly common in clinical studies and cancer studies that monitor various tissue samples for each subject. PMID:29281633

Outcome-Dependent Sampling Design and Inference for Cox's Proportional Hazards Model.

PubMed

Yu, Jichang; Liu, Yanyan; Cai, Jianwen; Sandler, Dale P; Zhou, Haibo

2016-11-01

We propose a cost-effective outcome-dependent sampling design for the failure time data and develop an efficient inference procedure for data collected with this design. To account for the biased sampling scheme, we derive estimators from a weighted partial likelihood estimating equation. The proposed estimators for regression parameters are shown to be consistent and asymptotically normally distributed. A criteria that can be used to optimally implement the ODS design in practice is proposed and studied. The small sample performance of the proposed method is evaluated by simulation studies. The proposed design and inference procedure is shown to be statistically more powerful than existing alternative designs with the same sample sizes. We illustrate the proposed method with an existing real data from the Cancer Incidence and Mortality of Uranium Miners Study.

Determination of the efficacy of preservation of non-eye area water-miscible cosmetic and toiletry formulations: collaborative study.

PubMed

Machtiger, N A; Fischler, G E; Adams, M C; Spielmaker, R; Graf, J F

2001-01-01

A collaborative study was conducted to test a method developed to distinguish between adequately and inadequately preserved cosmetic formulations. Nineteen laboratories participated in the study. Samples tested included shampoos, hair conditioners, oil-in-water emulsions, and water-in-oil-emulsions. Triplicate samples of 4 adequately preserved and 4 inadequately preserved cosmetic products were tested by each collaborative laboratory. Results showed that all inadequately preserved shampoo and conditioner samples failed to meet the acceptance criteria for adequately preserved formulations. Of the 51 preserved samples, 49 shampoos and 48 conditioners met the criteria for adequate preservation. All samples of inadequately preserved water-in-oil emulsions and oil-in-water emulsions failed to meet the acceptance criteria, whereas all adequately preserved emulsion formulations met the acceptance criteria.

Positron annihilation spectroscopy studies of bronze exposed to sandblasting at different pressure

NASA Astrophysics Data System (ADS)

Kurdyumov, S.; Siemek, K.; Horodek, P.

2017-11-01

An application of Doppler broadening of annihilation line spectroscopy to samples of beryllium bronze DIN-CuBe2 exposed to sandblasting is presented in performed studies. It is familiar that sandblasting introduces open-volume defects. Samples were sandblasted under different pressure for 1 minute using 110 μm particles of Al2O3. For a non-defected sample the constant value of S-parameter was detected. In the cases of sandblasted samples, S-parameter decreased when the depth enhanced. In our studies the thicknesses of defected zones were determined (it was c.a. 30 μm for a sample blasted under pressure of 1 bar and 110 μm - for 5 bar), and it was also observed that if sandblasting pressure is higher the defected zone is larger.

Factor analysis of Wechsler Adult Intelligence Scale-Revised in developmentally disabled persons.

PubMed

Di Nuovo, Santo F; Buono, Serafino

2006-12-01

The results of previous studies on the factorial structure of Wechsler Intelligence Scales are somewhat inconsistent across normal and pathological samples. To study specific clinical groups, such as developmentally disabled persons, it is useful to examine the factor structure in appropriate samples. A factor analysis was carried out using the principal component method and the Varimax orthogonal rotation on the Wechsler Adult Intelligence Scale (WAIS-R) in a sample of 203 developmentally disabled persons, with a mean age of 25 years 4 months. Developmental disability ranged from mild to moderate. Partially contrasting with previous studies on normal samples, results found a two-factor solution. Wechsler's traditional Verbal and Performance scales seems to be more appropriate for this sample than the alternative three-factor solution.

Evaluation of pesticide residues of organochlorine in vegetables and fruits in Qatar: statistical analysis.

PubMed

Al-Shamary, Noora M; Al-Ghouti, Mohammad A; Al-Shaikh, Ismail; Al-Meer, Saeed H; Ahmad, Talaat A

2016-03-01

The study aimed to examine the residues of organochlorines pesticides (OCPs) in vegetables and fruits in Qatar. A total of 127 samples was studied. Ninety percent of the imported samples recorded residues above the maximum residue levels (MRLs). The most frequently detected OCP in the samples was heptachlor (found in 75 samples). In the comparisons between the washed and unwashed samples, no significant differences were observed (P > 0.05). However, the effect of washing process with tap water depended on the type of vegetables and fruits.

The effect of liming on antibacterial and hormone levels in wastewater biosolids.

PubMed

Olszewski, Jennifer M; Lozano, Nuria; Haines, Christine; Rice, Clifford P; Ramirez, Mark; Torrents, Alba

2013-01-01

This study analyzes the effect of liming on levels of triclocarban (TCC), triclosan (TCS), estrone (E1), and progesterone (P), two antimicrobial agents and two natural hormones, respectively. Factors studied include lime particle size, mixing time, and overall lime contact time. The study results suggest that coarse lime may be more active than fine lime due to less interaction with surrounding air. Both TCS and TCC concentrations were lower in coarse limed samples versus unlimed samples and the decrease was a function of time. A similar, but statistically insignificant trend in TCC and TCS levels was observed in fine lime samples with respect to unlimed samples. Liming was also found to decrease apparent E1 levels, with more notable decreases in samples amended with coarse lime. P-levels significantly increased after 1-day of contact time, stabilizing over the next 14 days of the study period. This increase and stabilization of P-levels was attributed to the pH and moisture-driven conversion of more chemically complex steroids into P.

Cooperative investigation of precision and accuracy: In chemical analysis of silicate rocks

USGS Publications Warehouse

Schlecht, W.G.

1951-01-01

This is the preliminary report of the first extensive program ever organized to study the analysis of igneous rocks, a study sponsored by the United States Geological Survey, the Massachusetts Institute of Technology, and the Geophysical Laboratory of the Carnegie Institution of Washington. Large samples of two typical igneous rocks, a granite and a diabase, were carefully prepared and divided. Small samples (about 70 grams) of each were sent to 25 rock-analysis laboratories throughout the world; analyses of one or both samples were reported by 34 analysts in these laboratories. The results, which showed rather large discrepancies, are presented in histograms. The great discordance in results reflects the present unsatisfactory state of rock analysis. It is hoped that the ultimate establishment of standard samples and procedures will contribute to the improvement of quality of analyses. The two rock samples have also been thoroughly studied spectrographically and petrographically. Detailed reports of all the studies will be published.

Ventana immunohistochemistry ALK (D5F3) detection of ALK expression in pleural effusion samples of lung adenocarcinoma.

PubMed

Wang, Zheng; Wu, Xiaonan; Shi, Yuankai; Han, Xiaohong; Cheng, Gang; Cui, Di; Li, Lin; Zhang, Yuhui; Mu, Xinlin; Zhang, Li; Yang, Li; Di, Jing; Yu, Qi; Liu, Dongge

2015-08-01

To evaluate the Ventana IHC ALK (D5F3) assay for detecting anaplastic lymphoma kinase (ALK) protein expression in pleural effusion samples. Historical, selected (wild-type EGFR, K-RAS) pleural effusion cytologic blocks of lung adenocarcinoma samples (Study 1) and unselected lung adenocarcinoma pleural effusion cytologic blocks (Study 2) were tested by Ventana IHC ALK (D5F3) assay. Quantitative real-time-PCR was used to verify immunohistochemistry results. A total of 17 out of 100 (Study 1) and ten out of 104 (Study 2) pleural effusion samples were ALK expression positive by the Ventana IHC ALK (D5F3) assay. The ALK fusion results with immunohistochemistry and quantitative real-time-PCR had a concordance rate of 87.5% (κ = 0.886; p < 0.001). The Ventana IHC ALK (D5F3) assay is a reliable tool for detecting ALK protein expression in pleural effusion samples.

Defendant mental illness and juror decision-making: A comparison of sample types.

PubMed

Mossière, Annik; Maeder, Evelyn M

2015-01-01

Two studies were conducted with separate student and community samples to explore the effect of sample types and the influence of defendant mental illness on juror decision-making. Following the completion of a pre-trial questionnaire in which jurors' attitudes towards mental illness were assessed, participants were provided with a robbery trial transcript, wherein the mental illness of the defendant was manipulated. Participants then answered a questionnaire to assess their knowledge of the scenario, their verdict, verdict confidence, and sentencing decision. Limited relationships were found between the variables in both Study 1 and Study 2. Neither attitude ratings nor mental illness type had a significant effect on juror decisions. Samples differed in terms of the paths through which juror decisions were achieved. Findings suggest that sample type may be particularly relevant for this topic of study, and that future research is required on legal proceedings for cases involving a defendant with a mental illness. Copyright © 2015 Elsevier Ltd. All rights reserved.

Leachate Geochemical Results for Ash and Burned Soil Samples from the October 2007 Southern California Wildfires

USGS Publications Warehouse

Hageman, Philip L.; Plumlee, Geoffrey S.; Martin, Deborah A.; Hoefen, Todd M.; Meeker, Gregory P.; Adams, Monique; Lamothe, Paul J.; Anthony, Michael W.

2008-01-01

This report is the second release of leachate geochemical data included as part of a multidisciplinary study of ash and burned soil samples from the October 2007 wildfires in southern California. Geochemical data for the first set of samples were released in an Open-File Report (Plumlee and others, 2007). This study is a continuation of that work. The objectives of this leaching study are to aid in understanding the interactions of ash and burned soil with rainfall. For this study, 12 samples collected in early November 2007 were leached using the U.S. Geological Survey (USGS) Field Leach Test (FLT). Following leaching, sub-samples of the leachate were analyzed for pH and specific conductance. The leachate was then filtered, and aliquots were preserved for geochemical analysis. This report presents leachate geochemical data for pH, specific conductance, alkalinity, anions using ion chromatography (I.C.), cations using inductively coupled plasma?atomic mass spectrometry (ICP-MS), and mercury by continuous flow injection?cold vapor?atomic fluorescence (CVAFS).

A high-throughput robotic sample preparation system and HPLC-MS/MS for measuring urinary anatabine, anabasine, nicotine and major nicotine metabolites.

PubMed

Wei, Binnian; Feng, June; Rehmani, Imran J; Miller, Sharyn; McGuffey, James E; Blount, Benjamin C; Wang, Lanqing

2014-09-25

Most sample preparation methods characteristically involve intensive and repetitive labor, which is inefficient when preparing large numbers of samples from population-scale studies. This study presents a robotic system designed to meet the sampling requirements for large population-scale studies. Using this robotic system, we developed and validated a method to simultaneously measure urinary anatabine, anabasine, nicotine and seven major nicotine metabolites: 4-Hydroxy-4-(3-pyridyl)butanoic acid, cotinine-N-oxide, nicotine-N-oxide, trans-3'-hydroxycotinine, norcotinine, cotinine and nornicotine. We analyzed robotically prepared samples using high-performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometry in positive electrospray ionization mode using scheduled multiple reaction monitoring (sMRM) with a total runtime of 8.5 min. The optimized procedure was able to deliver linear analyte responses over a broad range of concentrations. Responses of urine-based calibrators delivered coefficients of determination (R(2)) of >0.995. Sample preparation recovery was generally higher than 80%. The robotic system was able to prepare four 96-well plate (384 urine samples) per day, and the overall method afforded an accuracy range of 92-115%, and an imprecision of <15.0% on average. The validation results demonstrate that the method is accurate, precise, sensitive, robust, and most significantly labor-saving for sample preparation, making it efficient and practical for routine measurements in large population-scale studies such as the National Health and Nutrition Examination Survey (NHANES) and the Population Assessment of Tobacco and Health (PATH) study. Published by Elsevier B.V.

The Study on Mental Health at Work: Design and sampling.

PubMed

Rose, Uwe; Schiel, Stefan; Schröder, Helmut; Kleudgen, Martin; Tophoven, Silke; Rauch, Angela; Freude, Gabriele; Müller, Grit

2017-08-01

The Study on Mental Health at Work (S-MGA) generates the first nationwide representative survey enabling the exploration of the relationship between working conditions, mental health and functioning. This paper describes the study design, sampling procedures and data collection, and presents a summary of the sample characteristics. S-MGA is a representative study of German employees aged 31-60 years subject to social security contributions. The sample was drawn from the employment register based on a two-stage cluster sampling procedure. Firstly, 206 municipalities were randomly selected from a pool of 12,227 municipalities in Germany. Secondly, 13,590 addresses were drawn from the selected municipalities for the purpose of conducting 4500 face-to-face interviews. The questionnaire covers psychosocial working and employment conditions, measures of mental health, work ability and functioning. Data from personal interviews were combined with employment histories from register data. Descriptive statistics of socio-demographic characteristics and logistic regressions analyses were used for comparing population, gross sample and respondents. In total, 4511 face-to-face interviews were conducted. A test for sampling bias revealed that individuals in older cohorts participated more often, while individuals with an unknown educational level, residing in major cities or with a non-German ethnic background were slightly underrepresented. There is no indication of major deviations in characteristics between the basic population and the sample of respondents. Hence, S-MGA provides representative data for research on work and health, designed as a cohort study with plans to rerun the survey 5 years after the first assessment.

Optimal designs for population pharmacokinetic studies of the partner drugs co-administered with artemisinin derivatives in patients with uncomplicated falciparum malaria.

PubMed

Jamsen, Kris M; Duffull, Stephen B; Tarning, Joel; Lindegardh, Niklas; White, Nicholas J; Simpson, Julie A

2012-07-11

Artemisinin-based combination therapy (ACT) is currently recommended as first-line treatment for uncomplicated malaria, but of concern, it has been observed that the effectiveness of the main artemisinin derivative, artesunate, has been diminished due to parasite resistance. This reduction in effect highlights the importance of the partner drugs in ACT and provides motivation to gain more knowledge of their pharmacokinetic (PK) properties via population PK studies. Optimal design methodology has been developed for population PK studies, which analytically determines a sampling schedule that is clinically feasible and yields precise estimation of model parameters. In this work, optimal design methodology was used to determine sampling designs for typical future population PK studies of the partner drugs (mefloquine, lumefantrine, piperaquine and amodiaquine) co-administered with artemisinin derivatives. The optimal designs were determined using freely available software and were based on structural PK models from the literature and the key specifications of 100 patients with five samples per patient, with one sample taken on the seventh day of treatment. The derived optimal designs were then evaluated via a simulation-estimation procedure. For all partner drugs, designs consisting of two sampling schedules (50 patients per schedule) with five samples per patient resulted in acceptable precision of the model parameter estimates. The sampling schedules proposed in this paper should be considered in future population pharmacokinetic studies where intensive sampling over many days or weeks of follow-up is not possible due to either ethical, logistic or economical reasons.

Lead as a legendary pollutant with emerging concern: Survey of lead in tap water in an old campus building using four sampling methods.

PubMed

Ng, Ding-Quan; Liu, Shu-Wei; Lin, Yi-Pin

2018-09-15

In this study, a sampling campaign with a total of nine sampling events investigating lead in drinking water was conducted at 7 sampling locations in an old building with lead pipes in service in part of the building on the National Taiwan University campus. This study aims to assess the effectiveness of four different sampling methods, namely first draw sampling, sequential sampling, random daytime sampling and flush sampling, in lead contamination detection. In 3 out of the 7 sampling locations without lead pipe, lead could not be detected (<1.1 μg/L) in most samples regardless of the sampling methods. On the other hand, in the 4 sampling locations where lead pipes still existed, total lead concentrations >10 μg/L were consistently observed in 3 locations using any of the four sampling methods while the remaining location was identified to be contaminated using sequential sampling. High lead levels were consistently measured by the four sampling methods in the 3 locations in which particulate lead was either predominant or comparable to soluble lead. Compared to first draw and random daytime samplings, although flush sampling had a high tendency to reduce total lead in samples in lead-contaminated sites, the extent of lead reduction was location-dependent and not dependent on flush durations between 5 and 10 min. Overall, first draw sampling and random daytime sampling were reliable and effective in determining lead contamination in this study. Flush sampling could reveal the contamination if the extent is severe but tends to underestimate lead exposure risk. Copyright © 2018 Elsevier B.V. All rights reserved.

Implementation of Web- Based Distance Education in Nursing Education in Turkey: A Sample Lesson in Patient Education

ERIC Educational Resources Information Center

Senyuva, Emine; Tasocak, Gülsün

2014-01-01

The research was carried out in 2005-2006 as a descriptive and methodological study. It aimed to obtain students' feedback and to serve as a source for future relevant studies. The setting of the study was Istanbul University Florence Nightingale Nursing College and at Istanbul University Bakirköy Health College. The sample of the study included…

Replication and contradiction of highly cited research papers in psychiatry: 10-year follow-up.

PubMed

Tajika, Aran; Ogawa, Yusuke; Takeshima, Nozomi; Hayasaka, Yu; Furukawa, Toshi A

2015-10-01

Contradictions and initial overestimates are not unusual among highly cited studies. However, this issue has not been researched in psychiatry. Aims: To assess how highly cited studies in psychiatry are replicated by subsequent studies. We selected highly cited studies claiming effective psychiatric treatments in the years 2000 through 2002. For each of these studies we searched for subsequent studies with a better-controlled design, or with a similar design but a larger sample. Among 83 articles recommending effective interventions, 40 had not been subject to any attempt at replication, 16 were contradicted, 11 were found to have substantially smaller effects and only 16 were replicated. The standardised mean differences of the initial studies were overestimated by 132%. Studies with a total sample size of 100 or more tended to produce replicable results. Caution is needed when a study with a small sample size reports a large effect. © The Royal College of Psychiatrists 2015.

Rapid regrowth and detection of microbial contaminants in equine fecal microbiome samples

PubMed Central

Beckers, Kalie F.; Childers, Gary W.

2017-01-01

Advances have been made to standardize 16S rRNA gene amplicon based studies for inter-study comparisons, yet there are many opportunities for systematic error that may render these comparisons improper and misleading. The fecal microbiome of horses has been examined previously, however, no universal horse fecal collection method and sample processing procedure has been established. This study was initialized in large part to ensure that samples collected by different individuals from different geographical areas (i.e., crowdsourced) were not contaminated due to less than optimal sampling or holding conditions. In this study, we examined the effect of sampling the surface of fecal pellets compared to homogenized fecal pellets, and also the effect of time of sampling after defecation on ‘bloom’ taxa (bloom taxa refers to microbial taxa that can grow rapidly in horse feces post-defecation) using v4 16S rRNA amplicon libraries. A total of 1,440,171 sequences were recovered from 65 horse fecal samples yielding a total of 3,422 OTUs at 97% similarity. Sampling from either surface or homogenized feces had no effect on diversity and little effect on microbial composition. Sampling at various time points (0, 2, 4, 6, 12 h) had a significant effect on both diversity and community composition of fecal samples. Alpha diversity (Shannon index) initially increased with time as regrowth taxa were detected in the amplicon libraries, but by 12 h the diversity sharply decreased as the community composition became dominated by a few bloom families, including Bacillaceae, Planococcaeae, and Enterococcaceae, and other families to a lesser extent. The results show that immediate sampling of horse feces must be done in order to ensure accurate representation of horse fecal samples. Also, several of the bloom taxa found in this study are known to occur in human and cattle feces post defecation. The dominance of these taxa in feces shortly after defecation suggests that the feces is an important habitat for these organisms, and horse fecal samples that were improperly stored can be identified by presence of bloom taxa. PMID:29091944

Methodological quality of behavioural weight loss studies: a systematic review

PubMed Central

Lemon, S. C.; Wang, M. L.; Haughton, C. F.; Estabrook, D. P.; Frisard, C. F.; Pagoto, S. L.

2018-01-01

Summary This systematic review assessed the methodological quality of behavioural weight loss intervention studies conducted among adults and associations between quality and statistically significant weight loss outcome, strength of intervention effectiveness and sample size. Searches for trials published between January, 2009 and December, 2014 were conducted using PUBMED, MEDLINE and PSYCINFO and identified ninety studies. Methodological quality indicators included study design, anthropometric measurement approach, sample size calculations, intent-to-treat (ITT) analysis, loss to follow-up rate, missing data strategy, sampling strategy, report of treatment receipt and report of intervention fidelity (mean = 6.3). Indicators most commonly utilized included randomized design (100%), objectively measured anthropometrics (96.7%), ITT analysis (86.7%) and reporting treatment adherence (76.7%). Most studies (62.2%) had a follow-up rate >75% and reported a loss to follow-up analytic strategy or minimal missing data (69.9%). Describing intervention fidelity (34.4%) and sampling from a known population (41.1%) were least common. Methodological quality was not associated with reporting a statistically significant result, effect size or sample size. This review found the published literature of behavioural weight loss trials to be of high quality for specific indicators, including study design and measurement. Identified for improvement include utilization of more rigorous statistical approaches to loss to follow up and better fidelity reporting. PMID:27071775

Dimensions of design space: a decision-theoretic approach to optimal research design.

PubMed

Conti, Stefano; Claxton, Karl

2009-01-01

Bayesian decision theory can be used not only to establish the optimal sample size and its allocation in a single clinical study but also to identify an optimal portfolio of research combining different types of study design. Within a single study, the highest societal payoff to proposed research is achieved when its sample sizes and allocation between available treatment options are chosen to maximize the expected net benefit of sampling (ENBS). Where a number of different types of study informing different parameters in the decision problem could be conducted, the simultaneous estimation of ENBS across all dimensions of the design space is required to identify the optimal sample sizes and allocations within such a research portfolio. This is illustrated through a simple example of a decision model of zanamivir for the treatment of influenza. The possible study designs include: 1) a single trial of all the parameters, 2) a clinical trial providing evidence only on clinical endpoints, 3) an epidemiological study of natural history of disease, and 4) a survey of quality of life. The possible combinations, samples sizes, and allocation between trial arms are evaluated over a range of cost-effectiveness thresholds. The computational challenges are addressed by implementing optimization algorithms to search the ENBS surface more efficiently over such large dimensions.

Samples in applied psychology: over a decade of research in review.

PubMed

Shen, Winny; Kiger, Thomas B; Davies, Stacy E; Rasch, Rena L; Simon, Kara M; Ones, Deniz S

2011-09-01

This study examines sample characteristics of articles published in Journal of Applied Psychology (JAP) from 1995 to 2008. At the individual level, the overall median sample size over the period examined was approximately 173, which is generally adequate for detecting the average magnitude of effects of primary interest to researchers who publish in JAP. Samples using higher units of analyses (e.g., teams, departments/work units, and organizations) had lower median sample sizes (Mdn ≈ 65), yet were arguably robust given typical multilevel design choices of JAP authors despite the practical constraints of collecting data at higher units of analysis. A substantial proportion of studies used student samples (~40%); surprisingly, median sample sizes for student samples were smaller than working adult samples. Samples were more commonly occupationally homogeneous (~70%) than occupationally heterogeneous. U.S. and English-speaking participants made up the vast majority of samples, whereas Middle Eastern, African, and Latin American samples were largely unrepresented. On the basis of study results, recommendations are provided for authors, editors, and readers, which converge on 3 themes: (a) appropriateness and match between sample characteristics and research questions, (b) careful consideration of statistical power, and (c) the increased popularity of quantitative synthesis. Implications are discussed in terms of theory building, generalizability of research findings, and statistical power to detect effects. PsycINFO Database Record (c) 2011 APA, all rights reserved

THE NEW YORK CITY URBAN DISPERSION PROGRAM MARCH 2005 FIELD STUDY: TRACER METHODS AND RESULTS.

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

WATSON, T.B.; HEISER, J.; KALB, P.

The Urban Dispersion Program March 2005 Field Study tracer releases, sampling, and analytical methods are described in detail. There were two days where tracer releases and sampling were conducted. A total of 16.0 g of six tracers were released during the first test day or Intensive Observation Period (IOP) 1 and 15.7 g during IOP 2. Three types of sampling instruments were used in this study. Sequential air samplers, or SAS, collected six-minute samples, while Brookhaven atmospheric tracer samplers (BATS) and personal air samplers (PAS) collected thirty-minute samples. There were a total of 1300 samples resulting from the two IOPs.more » Confidence limits in the sampling and analysis method were 20% as determined from 100 duplicate samples. The sample recovery rate was 84%. The integrally averaged 6-minute samples were compared to the 30-minute samples. The agreement was found to be good in most cases. The validity of using a background tracer to calculate sample volumes was examined and also found to have a confidence level of 20%. Methods for improving sampling and analysis are discussed. The data described in this report are available as Excel files. An additional Excel file of quality assured tracer data for use in model validation efforts is also available. The file consists of extensively quality assured BATS tracer data with background concentrations subtracted.« less

Filter forensics: microbiota recovery from residential HVAC filters.

PubMed

Maestre, Juan P; Jennings, Wiley; Wylie, Dennis; Horner, Sharon D; Siegel, Jeffrey; Kinney, Kerry A

2018-01-30

Establishing reliable methods for assessing the microbiome within the built environment is critical for understanding the impact of biological exposures on human health. High-throughput DNA sequencing of dust samples provides valuable insights into the microbiome present in human-occupied spaces. However, the effect that different sampling methods have on the microbial community recovered from dust samples is not well understood across sample types. Heating, ventilation, and air conditioning (HVAC) filters hold promise as long-term, spatially integrated, high volume samplers to characterize the airborne microbiome in homes and other climate-controlled spaces. In this study, the effect that dust recovery method (i.e., cut and elution, swabbing, or vacuuming) has on the microbial community structure, membership, and repeatability inferred by Illumina sequencing was evaluated. The results indicate that vacuum samples captured higher quantities of total, bacterial, and fungal DNA than swab or cut samples. Repeated swab and vacuum samples collected from the same filter were less variable than cut samples with respect to both quantitative DNA recovery and bacterial community structure. Vacuum samples captured substantially greater bacterial diversity than the other methods, whereas fungal diversity was similar across all three methods. Vacuum and swab samples of HVAC filter dust were repeatable and generally superior to cut samples. Nevertheless, the contribution of environmental and human sources to the bacterial and fungal communities recovered via each sampling method was generally consistent across the methods investigated. Dust recovery methodologies have been shown to affect the recovery, repeatability, structure, and membership of microbial communities recovered from dust samples in the built environment. The results of this study are directly applicable to indoor microbiota studies utilizing the filter forensics approach. More broadly, this study provides a better understanding of the microbial community variability attributable to sampling methodology and helps inform interpretation of data collected from other types of dust samples collected from indoor environments.

Fish stomach contents in benthic macroinvertebrate assemblage assessments.

PubMed

Tupinambás, T H; Pompeu, P S; Gandini, C V; Hughes, R M; Callisto, M

2015-01-01

The choice of sampling gears to assess benthic macroinvertebrate communities depends on environmental characteristics, study objectives, and cost effectiveness. Because of the high foraging capacity and diverse habitats and behaviors of benthophagous fishes, their stomach contents may offer a useful sampling tool in studies of benthic macroinvertebrates, especially in large, deep, fast rivers that are difficult to sample with traditional sediment sampling gear. Our objective was to compare the benthic macroinvertebrate communities sampled from sediments with those sampled from fish stomachs. We collected benthic macroinvertebrates and fish from three different habitat types (backwater, beach, riffle) in the wet season, drying season, and dry season along a single reach of the Grande River (Paraná River Basin, southeast Brazil). We sampled sediments through use of a Petersen dredge (total of 216 grabs) and used gill nets to sample fish (total of 36 samples). We analyzed the stomach contents of three commonly occurring benthophagous fish species (Eigenmannia virescens, Iheringichthys labrosus, Leporinus amblyrhynchus). Chironomids dominated in both sampling methods. Macroinvertebrate taxonomic composition and abundances from fish stomachs differed from those from sediment samples, but less so from riffles than from backwater and beach habitats. Macroinvertebrate taxa from E. virescens stomachs were more strongly correlated with sediment samples from all three habitats than were those from the other two species. The species accumulation curves and higher mean dispersion values, compared with with sediment samples suggest that E. virescens is more efficient than sediment samples and the other fish studied at collecting benthic taxa. We conclude that by analyzing the stomach contents of benthophagous fishes it is possible to assess important characteristics of benthic communities (dispersion, taxonomic composition and diversity). This is especially true for studies that only sample fish assemblages to evaluate aquatic ecosystem impacts. Therefore, this approach can be useful to amplify assessments of human impacts, and to incorporate additional bioindicators.

Sub-sampling genetic data to estimate black bear population size: A case study

USGS Publications Warehouse

Tredick, C.A.; Vaughan, M.R.; Stauffer, D.F.; Simek, S.L.; Eason, T.

2007-01-01

Costs for genetic analysis of hair samples collected for individual identification of bears average approximately US$50 [2004] per sample. This can easily exceed budgetary allowances for large-scale studies or studies of high-density bear populations. We used 2 genetic datasets from 2 areas in the southeastern United States to explore how reducing costs of analysis by sub-sampling affected precision and accuracy of resulting population estimates. We used several sub-sampling scenarios to create subsets of the full datasets and compared summary statistics, population estimates, and precision of estimates generated from these subsets to estimates generated from the complete datasets. Our results suggested that bias and precision of estimates improved as the proportion of total samples used increased, and heterogeneity models (e.g., Mh[CHAO]) were more robust to reduced sample sizes than other models (e.g., behavior models). We recommend that only high-quality samples (>5 hair follicles) be used when budgets are constrained, and efforts should be made to maximize capture and recapture rates in the field.

Calibration and field application of passive sampling for episodic exposure to polar organic pesticides in streams.

PubMed

Fernández, Diego; Vermeirssen, Etiënne L M; Bandow, Nicole; Muñoz, Katherine; Schäfer, Ralf B

2014-11-01

Rainfall-triggered runoff is a major driver of pesticide input in streams. Only few studies have examined the suitability of passive sampling to quantify such episodic exposures. In this study, we used Empore™ styrene-divinylbenzene reverse phase sulfonated disks (SDB disks) and event-driven water samples (EDS) to assess exposure to 15 fungicides and 4 insecticides in 17 streams in a German vineyard area during 4 rainfall events. We also conducted a microcosm experiment to determine the SDB-disk sampling rates and provide a free-software solution to derive sampling rates under time-variable exposure. Sampling rates ranged from 0.26 to 0.77 L d(-1) and time-weighted average (TWA) concentrations from 0.05 to 2.11 μg/L. The 2 sampling systems were in good agreement and EDS exceeded TWA concentrations on average by a factor of 3. Our study demonstrates that passive sampling is suitable to quantify episodic exposures from polar organic pesticides. Copyright © 2014 Elsevier Ltd. All rights reserved.

Giant African Pouched Rats as Detectors of Tuberculosis in Human Sputum: Comparison of Two Techniques for Sputum Presentation

ERIC Educational Resources Information Center

Wray, Alisha M.; Mahoney, Amanda; Weetjens, Bart J.; Cox, Christophe; Jubitana, Maureen; Kazwala, Rudovic; Mfinanga, Godfrey S.; Durgin, Amy; Poling, Alan

2013-01-01

Previous studies have shown that pouched rats can detect the presence of "Mycobacterium tuberculosis," which causes tuberculosis, in human sputum samples obtained from clinical facilities. Although pouched rats evaluate sputum samples quickly, preparing the samples is relatively slow. The present study evaluated whether the rats can detect…

Varieties of Stimulus Control in Matching-to-Sample: A Kernel Analysis

ERIC Educational Resources Information Center

Fields, Lanny; Garruto, Michelle; Watanabe, Mari

2010-01-01

Conditional discrimination or matching-to-sample procedures have been used to study a wide range of complex psychological phenomena with infrahuman and human subjects. In most studies, the percentage of trials in which a subject selects the comparison stimulus that is related to the sample stimulus is used to index the control exerted by the…

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…

An Assessment of Workplace Skills Acquired by Students of Vocational and Technical Education Institutions

ERIC Educational Resources Information Center

Bakar, Ab Rahim; Mohamed, Shamsiah; Hamzah, Ramlah

2013-01-01

This study was performed to identify the employability skills of technical students from the Industrial Training Institutes (ITI) and Indigenous People's Trust Council (MARA) Skills Training Institutes (IKM) in Malaysia. The study sample consisted of 850 final year trainees of IKM and ITI. The sample was chosen by a random sampling procedure from…

Application of the Tripartite Model to a Complicated Sample of Residential Youth with Externalizing Problems

ERIC Educational Resources Information Center

Chin, Eu Gene; Ebesutani, Chad; Young, John

2013-01-01

The tripartite model of anxiety and depression has received strong support among child and adolescent populations. Clinical samples of children and adolescents in these studies, however, have usually been referred for treatment of anxiety and depression. This study investigated the fit of the tripartite model with a complicated sample of…

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR SAMPLING WEIGHT CALCULATION (IIT-A-9.0)

EPA Science Inventory

The purpose of this SOP is to describe the procedures undertaken to calculate sampling weights. The sampling weights are needed to obtain weighted statistics of the study data. This SOP uses data that have been properly coded and certified with appropriate QA/QC procedures by th...

Scientific Temper among Academically High and Low Achieving Adolescent Girls

ERIC Educational Resources Information Center

Kour, Sunmeet

2015-01-01

The present study was undertaken to compare the scientific temper of high and low achieving adolescent girl students. Random sampling technique was used to draw the sample from various high schools of District Srinagar. The sample for the present study consisted of 120 school going adolescent girls (60 high and 60 low achievers). Data was…

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR FIELD COLLECTION OF YARD COMPOSITE SOIL SAMPLES (UA-F-5.1)

EPA Science Inventory

The purpose of this SOP is to establish a uniform procedure for the collection of yard composite soil samples in the field. This procedure was followed to ensure consistent and reliable collection of outdoor soil samples during the Arizona NHEXAS project and the "Border" study. ...

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR TRACKING SYSTEM (UA-D-28.0)

EPA Science Inventory

The Arizona Border Study used a system that tracks what occurs to a sample and provides the status of that sample at any given time. In essence, the tracking system provides an electronic chain of custody record for each sample as it moves through the project. This is achieved ...

The Influence of Principals Self Personality Values towards Their Work Culture

ERIC Educational Resources Information Center

Asri, Muhammad; Tahir, Lokman Bin Mohd.

2014-01-01

This study aimed to identify the influence of principals' self personality values toward teachers' work culture in high schools. The sample consisted of 34 principals from SMAN, SMKN and MAN in the City of Makassar, South Sulawesi Indonesia. The sample of this study is population sample. The instrument used was a questionnaire. Data were analyzed…

Molecular detection of fungi of public health importance in wild animals from Southern Brazil.

PubMed

Losnak, Debora O; Rocha, Francielle R; Almeida, Barbara S; Batista, Keila Z S; Althoff, Sérgio L; Haupt, Josiane; Ruiz, Luciana S; Anversa, Laís; Lucheis, Simone B; Paiz, Laís M; Donalisio, Maria Rita; Richini Pereira, Virginia B

2018-07-01

Some animals have an important relationship with fungal infections, and searching for pathogens in animal samples may be an opportunity for eco-epidemiological research. Since studies involving wildlife are generally restricted, using samples from road kills is an alternative. The aim of this study was to verify whether pathogenic fungi of public health importance occur in wildlife road kills from Santa Catarina State, Brazil. Organ samples (n = 1063) from 297 animals were analysed according to Polymerase Chain Reaction (PCR) using universal primers to detect fungi in general and, subsequently, using primers specific to Paracoccidioides brasiliensis, Histoplasma capsulatum and Cryptococcus spp. There were 102 samples positive for fungal species. Eight samples were positive for P. brasiliensis, three samples were positive for Cryptococcus spp. and one sample had coinfection by these two fungi. No sample was positive for Histoplasma spp. according to the molecular detection. Genetic sequencing allowed the identification of Fungal sp. in 89 samples, Cryptococcus neoformans in two samples and Aspergillus penicillioides in three samples. This study shows the importance of wild animals in the epidemiology of fungal infections and assists in the mapping of pathogen occurrence in a region that was not previously evaluated. © 2018 Blackwell Verlag GmbH.

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

PubMed

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

2012-04-27

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

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

PubMed Central

2012-01-01

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

Experiential sampling in the study of multiple personality disorder.

PubMed

Loewenstein, R J; Hamilton, J; Alagna, S; Reid, N; deVries, M

1987-01-01

The authors describe the application of experiential sampling, a new time-sampling method, to the assessment of rapid state changes in a woman with multiple personality disorder. She was signaled at random intervals during study periods and asked to provide information on alternate personality switches, amnesia, and mood state. The alternates displayed some characteristics that were as different as those occurring between separate individuals studied previously with this method. There were notable discrepancies between the self-report study data and information reported during therapy hours. The authors conclude that the phenomenology of multiple personality disorder is frequently more complex than is suspected early in the course of treatment.

Field-based random sampling without a sampling frame: control selection for a case-control study in rural Africa.

PubMed

Crampin, A C; Mwinuka, V; Malema, S S; Glynn, J R; Fine, P E

2001-01-01

Selection bias, particularly of controls, is common in case-control studies and may materially affect the results. Methods of control selection should be tailored both for the risk factors and disease under investigation and for the population being studied. We present here a control selection method devised for a case-control study of tuberculosis in rural Africa (Karonga, northern Malawi) that selects an age/sex frequency-matched random sample of the population, with a geographical distribution in proportion to the population density. We also present an audit of the selection process, and discuss the potential of this method in other settings.

MRI and unilateral NMR study of reindeer skin tanning processes.

PubMed

Zhu, Lizheng; Del Federico, Eleonora; Ilott, Andrew J; Klokkernes, Torunn; Kehlet, Cindie; Jerschow, Alexej

2015-04-07

The study of arctic or subarctic indigenous skin clothing material, known for its design and ability to keep the body warm, provides information about the tanning materials and techniques. The study also provides clues about the culture that created it, since tanning processes are often specific to certain indigenous groups. Untreated skin samples and samples treated with willow (Salix sp) bark extract and cod liver oil are compared in this study using both MRI and unilateral NMR techniques. The two types of samples show different proton spatial distributions and different relaxation times, which may also provide information about the tanning technique and aging behavior.

Guidelines for Design and Sampling for Cyanobacterial Toxin and Taste-and-Odor Studies in Lakes and Reservoirs

USGS Publications Warehouse

Graham, Jennifer L.; Loftin, Keith A.; Ziegler, Andrew C.; Meyer, Michael T.

2008-01-01

Cyanobacteria and associated toxins and taste-and-odor compounds are of increasing environmental concern. However, consistent guidelines for the development of studies assessing cyanobacterial toxins and taste-and-odor compounds presently are not available. This report provides guidance for the development of scientific studies of cyanobacteria and associated by-products in lakes and reservoirs. Topics include: background information on cyanobacteria, toxins, and taste-and-odor compounds; spatial and temporal considerations that are unique to the cyanobacteria in lakes and reservoirs; common study types, objectives, and approaches for studies of cyanobacteria and associated toxins and taste-and-odor compounds; general guidelines for collecting samples; and information on sample handling, preparation, processing, and shipping.

Utility of capillary microsampling for rat pharmacokinetic studies: Comparison of tail-vein bleed to jugular vein cannula sampling.

PubMed

Korfmacher, Walter; Luo, Yongyi; Ho, Stacy; Sun, Wei; Shen, Liduo; Wang, Jie; Wu, Zhongtao; Guo, Yang; Snow, Gregory; O'Shea, Thomas

2015-01-01

Serial sampling methods have been used for rat pharmacokinetic (PK) studies for over 20 years. Currently, it is still common to take 200-250 μL of blood at each timepoint when performing a PK study in rats and using serial sampling. While several techniques have been employed for collecting blood samples from rats, there is only limited published data to compare these methods. Recently, microsampling (≤ 50 μL) techniques have been reported as an alternative process for collecting blood samples from rats. In this report, five compounds were dosed orally into rats. For three proprietary compounds, jugular vein cannula (JVC) sampling was used to collect whole blood and plasma samples and capillary microsampling (CMS) was used to collect blood samples from the tail vein of the same animal. For the two other compounds, marketed drugs fluoxetine and glipizide, JVC sampling was used to collect both whole blood and blood CMS samples while tail-vein sampling from the same rats was also used to collect both whole blood and blood CMS samples. For the three proprietary compounds, the blood AUC as well as the blood concentration-time profile that were obtained from the tail vein were different from those obtained via JVC sampling. For fluoxetine, the blood total exposure (AUC) was not statistically different when comparing tail-vein sampling to JVC sampling, however the blood concentration-time profile that was obtained from the tail vein was different than the one obtained from JVC sampling. For glipizide, the blood AUC and concentration-time profile were not statistically different when comparing the tail-vein sampling to the JVC sampling. For both fluoxetine and glipizide, the blood concentration profiles obtained from CMS were equivalent to the blood concentration profiles obtained from the standard whole blood sampling, collected at the same sampling site. The data in this report provide strong evidence that blood CMS is a valuable small volume blood sampling approach for rats and that it provides results for test compound concentrations that are equivalent to those obtained from traditional whole blood sampling. The data also suggest that for some compounds, the concentration-time profile that is obtained for a test compound based on sampling from a rat tail vein may be different from that obtained from rat JVC sampling. In some cases, this shift in the concentration-time profile will result in different PK parameters for the test compound. Based on these observations, it is recommended that a consistent blood sampling method should be used for serial microsampling in discovery rat PK studies when testing multiple new chemical entities. If the rat tail vein sampling method is selected for PK screening, then conducting a bridging study on the lead compound is recommended to confirm that the rat PK obtained from JVC sampling is comparable to the tail-vein sampling. Copyright © 2015 Elsevier Inc. All rights reserved.

Planning and setting objectives in field studies: Chapter 2

USGS Publications Warehouse

Fisher, Robert N.; Dodd, C. Kenneth

2016-01-01

This chapter enumerates the steps required in designing and planning field studies on the ecology and conservation of reptiles, as these involve a high level of uncertainty and risk. To this end, the chapter differentiates between goals (descriptions of what one intends to accomplish) and objectives (the measurable steps required to achieve the established goals). Thus, meeting a specific goal may require many objectives. It may not be possible to define some of them until certain experiments have been conducted; often evaluations of sampling protocols are needed to increase certainty in the biological results. And if sampling locations are fixed and sampling events are repeated over time, then both study-specific covariates and sampling-specific covariates should exist. Additionally, other critical design considerations for field study include obtaining permits, as well as researching ethics and biosecurity issues.

Electron Spin Resonance (ESR) Studies of Returned Comet Nucleus Samples

NASA Technical Reports Server (NTRS)

Tsay, Fun-Dow; Kim, Soon Sam; Liang, Ranty H.

1997-01-01

Electron Spin Resonance (ESR) studies have been carried out on organic and inorganic free radicals generated by gamma-ray and/or UV-irradiation and trapped in ice matrices. It is suggested that the concentration of these free radicals together with their thermal stability can be used as an accurate built-in geothermometer and radiation probe for returned comet nucleus sample studies. ESR studies have also been carried out on paramagnetic (Mn(2+), Ti(3+), and Fe(3+)) and ferromagnetic (ferric oxide and metallic iron) centers known to be present in terrestrial and extraterrestrial samples. The presence or absence of these magnetic centers coupled with their characteristic ESR lineshape can be used to investigate the shock effects, quenching/cooling rate and oxidation-reduction conditions in the formation and subsequent evolution of returned comet nucleus samples.

Improved imputation accuracy in Hispanic/Latino populations with larger and more diverse reference panels: applications in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

PubMed Central

Nelson, Sarah C.; Stilp, Adrienne M.; Papanicolaou, George J.; Taylor, Kent D.; Rotter, Jerome I.; Thornton, Timothy A.; Laurie, Cathy C.

2016-01-01

Imputation is commonly used in genome-wide association studies to expand the set of genetic variants available for analysis. Larger and more diverse reference panels, such as the final Phase 3 of the 1000 Genomes Project, hold promise for improving imputation accuracy in genetically diverse populations such as Hispanics/Latinos in the USA. Here, we sought to empirically evaluate imputation accuracy when imputing to a 1000 Genomes Phase 3 versus a Phase 1 reference, using participants from the Hispanic Community Health Study/Study of Latinos. Our assessments included calculating the correlation between imputed and observed allelic dosage in a subset of samples genotyped on a supplemental array. We observed that the Phase 3 reference yielded higher accuracy at rare variants, but that the two reference panels were comparable at common variants. At a sample level, the Phase 3 reference improved imputation accuracy in Hispanic/Latino samples from the Caribbean more than for Mainland samples, which we attribute primarily to the additional reference panel samples available in Phase 3. We conclude that a 1000 Genomes Project Phase 3 reference panel can yield improved imputation accuracy compared with Phase 1, particularly for rare variants and for samples of certain genetic ancestry compositions. Our findings can inform imputation design for other genome-wide association studies of participants with diverse ancestries, especially as larger and more diverse reference panels continue to become available. PMID:27346520

Supercritical Fluid Extraction and Analysis of Tropospheric Aerosol Particles

NASA Astrophysics Data System (ADS)

Hansen, Kristen J.

An integrated sampling and supercritical fluid extraction (SFE) cell has been designed for whole-sample analysis of organic compounds on tropospheric aerosol particles. The low-volume extraction cell has been interfaced with a sampling manifold for aerosol particle collection in the field. After sample collection, the entire SFE cell was coupled to a gas chromatograph; after on-line extraction, the cryogenically -focused sample was separated and the volatile compounds detected with either a mass spectrometer or a flame ionization detector. A 20-minute extraction at 450 atm and 90 ^circC with pure supercritical CO _2 is sufficient for quantitative extraction of most volatile compounds in aerosol particle samples. A comparison between SFE and thermal desorption, the traditional whole-sample technique for analyses of this type, was performed using ambient aerosol particle samples, as well as samples containing known amounts of standard analytes. The results of these studies indicate that SFE of atmospheric aerosol particles provides quantitative measurement of several classes of organic compounds. SFE provides information that is complementary to that gained by the thermal desorption analysis. The results also indicate that SFE with CO _2 can be validated as an alternative to thermal desorption for quantitative recovery of several organic compounds. In 1989, the organic constituents of atmospheric aerosol particles collected at Niwot Ridge, Colorado, along with various physical and meteorological data, were measured during a collaborative field study. Temporal changes in the composition of samples collected during summertime at the rural site were studied. Thermal desorption-GC/FID was used to quantify selected compounds in samples collected during the field study. The statistical analysis of the 1989 Niwot Ridge data set is presented in this work. Principal component analysis was performed on thirty-one variables selected from the data set in order to ascertain different source and process components, and to examine concentration changes in groups of variables with respect to time of day and meteorological conditions. Seven orthogonal groups of variables resulted from the statistical analysis; the groups serve as molecular markers for different biologic and anthropogenic emission sources. In addition, the results of the statistical analysis were used to investigate how several emission source contributions vary with respect to local atmospheric dynamics. Field studies were conducted in the urban environment in and around Boulder, CO. to characterize the dynamics, chemistry, and emission sources which affect the composition and concentration of different size-fractions of aerosol particles in the Boulder air mass. Relationships between different size fractions of particles and some gas-phase pollutants were elucidated. These field studies included an investigation of seasonal variations in the organic content and concentration of aerosol particles, and how these characteristics are related to local meteorology and to the concentration of some gas-phase pollutants. The elemental and organic composition of aerosol particles was investigated according to particle size in preliminary studies of size-differentiated samples of aerosol particles. In order to aid in future studies of urban aerosol particles, samples were collected at a forest fire near Boulder. Molecular markers specific to wood burning processes will be useful indicators of residential wood burning activities in future field studies.

Biostatistics Series Module 5: Determining Sample Size

PubMed Central

Hazra, Avijit; Gogtay, Nithya

2016-01-01

Determining the appropriate sample size for a study, whatever be its type, is a fundamental aspect of biomedical research. An adequate sample ensures that the study will yield reliable information, regardless of whether the data ultimately suggests a clinically important difference between the interventions or elements being studied. The probability of Type 1 and Type 2 errors, the expected variance in the sample and the effect size are the essential determinants of sample size in interventional studies. Any method for deriving a conclusion from experimental data carries with it some risk of drawing a false conclusion. Two types of false conclusion may occur, called Type 1 and Type 2 errors, whose probabilities are denoted by the symbols σ and β. A Type 1 error occurs when one concludes that a difference exists between the groups being compared when, in reality, it does not. This is akin to a false positive result. A Type 2 error occurs when one concludes that difference does not exist when, in reality, a difference does exist, and it is equal to or larger than the effect size defined by the alternative to the null hypothesis. This may be viewed as a false negative result. When considering the risk of Type 2 error, it is more intuitive to think in terms of power of the study or (1 − β). Power denotes the probability of detecting a difference when a difference does exist between the groups being compared. Smaller α or larger power will increase sample size. Conventional acceptable values for power and α are 80% or above and 5% or below, respectively, when calculating sample size. Increasing variance in the sample tends to increase the sample size required to achieve a given power level. The effect size is the smallest clinically important difference that is sought to be detected and, rather than statistical convention, is a matter of past experience and clinical judgment. Larger samples are required if smaller differences are to be detected. Although the principles are long known, historically, sample size determination has been difficult, because of relatively complex mathematical considerations and numerous different formulas. However, of late, there has been remarkable improvement in the availability, capability, and user-friendliness of power and sample size determination software. Many can execute routines for determination of sample size and power for a wide variety of research designs and statistical tests. With the drudgery of mathematical calculation gone, researchers must now concentrate on determining appropriate sample size and achieving these targets, so that study conclusions can be accepted as meaningful. PMID:27688437

Ground-Water Quality Beneath Irrigated Cropland of the Northern and Southern High Plains Aquifer, Nebraska and Texas, 2003-04

USGS Publications Warehouse

Stanton, Jennifer S.; Fahlquist, Lynne

2006-01-01

A study of the quality of ground water beneath irrigated cropland was completed for the northern and southern High Plains aquifer. Ground-water samples were collected from 30 water-table monitoring wells in the northern agricultural land-use (NAL) study area in Nebraska in 2004 and 29 water-table monitoring wells in the southern agricultural land-use (SAL) study area in Texas in 2003. The two study areas represented different agricultural and hydrogeologic settings. The primary crops grown in the NAL study area were corn and soybeans, and the primary crop in the SAL study area was cotton. Overall, pesticide and fertilizer application rates were larger in the NAL study area. Also, precipitation and recharge rates were greater in the NAL study area, and depths to water and evapotranspiration rates were greater in the SAL study area. Ground-water quality beneath irrigated cropland was different in the two study areas. Nitrate concentrations were larger and pesticide detections were more frequent in the NAL study area. Nitrate concentrations in NAL samples ranged from 1.96 to 106 mg/L (milligrams per liter) as nitrogen, with a median concentration of 10.6 mg/L. Water in 73 percent of NAL samples had at least one pesticide or pesticide degradate detected. Most of the pesticide compounds detected (atrazine, alachlor, metolachlor, simazine, and degradates of those pesticides) are applied to corn and soybean fields. Nitrate concentrations in SAL samples ranged from 0.96 to 21.6 mg/L, with a median of 4.12 mg/L. Water in 24 percent of SAL samples had at least one pesticide or pesticide degradate detected. The pesticide compounds detected were deethylatrazine (a degradate of atrazine and propazine), propazine, fluometuron, and tebuthiuron. Most of the pesticides detected are applied to cotton fields. Dissolved-solids concentrations were larger in the SAL area and were positively correlated with both nitrate and chloride concentrations, suggesting a combination of human and natural sources. Dissolved-solids concentrations in NAL samples ranged from 272 to 2,160 mg/L, with a median of 442 mg/L, and dissolved solids in SAL samples ranged from 416 to 3,580 mg/L, with a median of 814 mg/L.

Concentrations of the Allelochemical (+/-)-catechin IN Centaurea maculosa soils.

PubMed

Perry, Laura G; Thelen, Giles C; Ridenour, Wendy M; Callaway, Ragan M; Paschke, Mark W; Vivanco, Jorge M

2007-12-01

The phytotoxin (+/-)-catechin has been proposed to mediate invasion and autoinhibition by the Eurasian plant Centaurea maculosa (spotted knapweed). The importance of (+/-)-catechin to C. maculosa ecology depends in part on whether sufficient catechin concentrations occur at appropriate times and locations within C. maculosa soil to influence neighboring plants. Previous research on catechin in C. maculosa soils has yielded conflicting results, with some studies finding high soil catechin concentrations and other, more recent studies finding little or no catechin in field soils. Here, we report the most extensive study of soil catechin concentrations to date. We examined soil catechin concentrations in 402 samples from 11 C. maculosa sites in North America sampled in consecutive months over 1 yr, excluding winter months. One site was sampled on seven dates, another was sampled twice, and the remaining nine sites were each sampled once on a range of sampling dates. Methods used were similar to those with which we previously measured high soil catechin concentrations. We detected catechin only in the site that was sampled on seven dates and only on one sampling date in that site (May 16 2006), but in all samples collected on that date. The mean soil catechin concentration on that date was 0.65 +/- 0.45 (SD) mg g(-1), comparable to previously reported high concentrations. There are a number of possible explanations for the infrequency with which we detected soil catechin in this work compared to previous studies. Differences in results could reflect spatial and temporal variation in catechin exudation or degradation, as we examined different sites in a different year from most previous studies. Also, large quantities of catechin were detected in blanks for two sampling periods in the present study, leading us to discard those data. This contamination suggests that previous reports of high catechin concentrations that did not include blanks should be viewed with caution. Our results suggest that pure catechin is only rarely present in C. maculosa bulk soils. Thus, although catechin may play a role in C. maculosa invasion, the infrequency of soil catechin that we determined in this study suggests that we cannot be as certain of its role as previous reports of high soil catechin concentrations suggested.

Latin American Study of Nutrition and Health (ELANS): rationale and study design.

PubMed

Fisberg, M; Kovalskys, I; Gómez, G; Rigotti, A; Cortés, L Y; Herrera-Cuenca, M; Yépez, M C; Pareja, R G; Guajardo, V; Zimberg, I Z; Chiavegatto Filho, A D P; Pratt, M; Koletzko, B; Tucker, K L

2016-01-30

Obesity is growing at an alarming rate in Latin America. Lifestyle behaviours such as physical activity and dietary intake have been largely associated with obesity in many countries; however studies that combine nutrition and physical activity assessment in representative samples of Latin American countries are lacking. The aim of this study is to present the design rationale of the Latin American Study of Nutrition and Health/Estudio Latinoamericano de Nutrición y Salud (ELANS) with a particular focus on its quality control procedures and recruitment processes. The ELANS is a multicenter cross-sectional nutrition and health surveillance study of a nationally representative sample of urban populations from eight Latin American countries (Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Perú and Venezuela). A standard study protocol was designed to evaluate the nutritional intakes, physical activity levels, and anthropometric measurements of 9000 enrolled participants. The study was based on a complex, multistage sample design and the sample was stratified by gender, age (15 to 65 years old) and socioeconomic level. A small-scale pilot study was performed in each country to test the procedures and tools. This study will provide valuable information and a unique dataset regarding Latin America that will enable cross-country comparisons of nutritional statuses that focus on energy and macro- and micronutrient intakes, food patterns, and energy expenditure. Clinical Trials NCT02226627.

Effect of Study Design on Sample Size in Studies Intended to Evaluate Bioequivalence of Inhaled Short‐Acting β‐Agonist Formulations

PubMed Central

Zeng, Yaohui; Singh, Sachinkumar; Wang, Kai

2017-01-01

Abstract Pharmacodynamic studies that use methacholine challenge to assess bioequivalence of generic and innovator albuterol formulations are generally designed per published Food and Drug Administration guidance, with 3 reference doses and 1 test dose (3‐by‐1 design). These studies are challenging and expensive to conduct, typically requiring large sample sizes. We proposed 14 modified study designs as alternatives to the Food and Drug Administration–recommended 3‐by‐1 design, hypothesizing that adding reference and/or test doses would reduce sample size and cost. We used Monte Carlo simulation to estimate sample size. Simulation inputs were selected based on published studies and our own experience with this type of trial. We also estimated effects of these modified study designs on study cost. Most of these altered designs reduced sample size and cost relative to the 3‐by‐1 design, some decreasing cost by more than 40%. The most effective single study dose to add was 180 μg of test formulation, which resulted in an estimated 30% relative cost reduction. Adding a single test dose of 90 μg was less effective, producing only a 13% cost reduction. Adding a lone reference dose of either 180, 270, or 360 μg yielded little benefit (less than 10% cost reduction), whereas adding 720 μg resulted in a 19% cost reduction. Of the 14 study design modifications we evaluated, the most effective was addition of both a 90‐μg test dose and a 720‐μg reference dose (42% cost reduction). Combining a 180‐μg test dose and a 720‐μg reference dose produced an estimated 36% cost reduction. PMID:29281130

Social Anxiety Disorder and Victimization in a Community Sample of Adolescents

ERIC Educational Resources Information Center

Gren-Landell, Malin; Aho, Nikolas; Andersson, Gerhard; Svedin, Carl Goran

2011-01-01

Despite high prevalence rates of social anxiety disorder (SAD) and high rates of victimization in adolescents, studies on the relationship between these phenomena are missing. In the present study we report associations between SAD and multiple victimization experiences in a community sample of adolescents. A cross-sectional study was conducted on…

Does Built Environment Matter to Early Adolescents' Physical Activity?

ERIC Educational Resources Information Center

Lin, Jen-Jia; Ting, Tzu-Cheng

2014-01-01

This study examined the relationship of built environments to physical activity among adolescents aged 12 to 14 years old. The study sample included 269 junior high school students studying in Nangang District, Taipei, Taiwan. Sample physical activity data were obtained by surveying adolescents using a self-administered short version of the…

A Study on Chocolate Consumption in Prospective Teachers

ERIC Educational Resources Information Center

Ozgen, Leyla

2016-01-01

This study was planned and conducted to determine the chocolate consumption habits of prospective teachers. The study population was comprised of students attending the Faculty of Education at Gazi University in Ankara and the sample consisted of 251 prospective teachers selected with simple random sampling. 96.4% and 3.6% of the prospective…

Solutions to Faculty Work Overload: A Study of Job Sharing

ERIC Educational Resources Information Center

Freeman, Brenda J.; Coll, Kenneth M.

2009-01-01

This study investigated the opinions of a national sample of counselor education chairs and college of education deans regarding the advantages and disadvantages of faculty job sharing. Results showed favorable responses toward faculty job sharing from approximately half the sample, despite limited experience with job sharing. The study found few…

Methods for measuring populations of small, diurnal forest birds.

Treesearch

D.A. Manuwal; A.B. Carey

1991-01-01

Before a bird population is measured, the objectives of the study should be clearly defined. Important factors to be considered in designing a study are study site selection, plot size or transect length, distance between sampling points, duration of counts, and frequency and timing of sampling. Qualified field personnel are especially important. Assumptions applying...

Sedentary lifestyle and its relation to cardiovascular risk factors, insulin resistance and inflammatory profile

USDA-ARS?s Scientific Manuscript database

The objective of this study is to analyze the association between sitting time and biomarkers of insulin resistance and inflammation in a sample of healthy male workers. A cross-sectional study was carried out in a sample of 929 volunteers belonging to the Aragon Workers' Health Study cohort. Sociod...

Paternal Alcoholism, Family Functioning, and Infant Mental Health

ERIC Educational Resources Information Center

Fitzgerald, Hiram E.; Eiden, Rina Das

2007-01-01

The authors share results from two longitudinal studies exploring the impact of father's alcohol use on child development. The Michigan Longitudinal Study (MLS) has followed a sample of alcoholic families with 3-5 year old children for 20 years. The Buffalo Longitudinal Study (BLS) has followed a sample of alcoholic and nonalcoholic families…

Career College Governance: A Study of the Faculty's Propensity to Participate

ERIC Educational Resources Information Center

King, Stephen H.

2012-01-01

This study investigated faculty perceptions of and propensity to participate in shared governance activities in proprietary, post-secondary educational institutions. The sample population for this study (n = 22) included adjunct and full-time faculty members and administrators selected through a snowball sampling method and initially inclusive of…

Papers presented to the Conference on Luna 24. [lunar soil studies

NASA Technical Reports Server (NTRS)

1977-01-01

Topics covered include: the regional geology, geochemistry, and geophysics of Mare Crisium and the Luna 24 landing site; the petrology, mineral chemistry, and cooling histories of lithic fragments, the chemistry, isotopic studies, and geochronology of Luna 24 samples; and regolith studies of soil samples. Subject and topical indexes are provided.

State Estimates of Disability in America. Disability Statistics Report 3.

ERIC Educational Resources Information Center

LaPlante, Mitchell P.

This study presents and discusses existing data on disability by state, from the 1980 and 1990 censuses, the Current Population Survey (CPS), and the National Health Interview Survey (NHIS). The study used direct methods for states with large sample sizes and synthetic estimates for states with low sample sizes. The study's highlighted findings…

Trends in Turkish Education Studies

ERIC Educational Resources Information Center

Varisoglu, Behice; Sahin, Abdullah; Goktas, Yuksel

2013-01-01

The purpose of this study was to determine trends in the subject areas, methods, data collection tools, data analysis methods, and sample types used in recent studies on Turkish education, published in journals from 2000-2011. A total of 558 articles from 44 journals were selected from databases by the purposive sampling method and examined using…

In vitro test of external Qigong

PubMed Central

Yount, Garret; Solfvin, Jerry; Moore, Dan; Schlitz, Marilyn; Reading, Melissa; Aldape, Ken; Qian, Yifang

2004-01-01

Background Practitioners of the alternative medical practice 'external Qigong' generally claim the ability to emit or direct "healing energy" to treat patients. We investigated the ability of experienced Qigong practitioners to enhance the healthy growth of cultured human cells in a series of studies, each following a rigorously designed protocol with randomization, blinding and controls for variability. Methods Qigong practitioners directed healing intentionality toward normal brain cell cultures in a basic science laboratory. Qigong treatments were delivered for 20 minutes from a minimum distance of 10 centimeters. Cell proliferation was measured by a standard colony-forming efficiency (CFE) assay and a CFE ratio (CFE for treated samples/CFE for sham samples) was the dependent measure for each experiment. Results During a pilot study (8 experiments), a trend of increased cell proliferation in Qigong-treated samples (CFE Qigong/sham ratios > 1.0) was observed (P = 0.162). In a formal study (28 experiments), a similar trend was observed, with Qigong-treated samples showing on average more colony formation than sham samples (P = 0.036). In a replication study (60 experiments), no significant difference between Qigong-treated samples and sham samples was observed (P = 0.465). Conclusion We observed an apparent increase in the proliferation of cultured cells following external Qigong treatment by practitioners under strictly controlled conditions, but we did not observe this effect in a replication study. These results suggest the need for more controlled and thorough investigation of external Qigong before scientific validation is claimed. PMID:15102336

Effects of cocoa butter triacylglycerides and minor compounds on oil migration.

PubMed

Wang, Hao; Maleky, Farnaz

2018-04-01

In a multi-component chocolate product, oil migration, from high oil content filling into chocolate, is one of the major contributors to the product quality loss. Among various parameters influencing oil diffusivity, cocoa butter is studied intensively. Studies have shown that the rate of oil transportion in cocoa butter is affected by its composition, the way that it is crystallized, and also the storage conditions. To model and study effects of cocoa butter type and processing conditions on oil migration, five different cocoa butter samples were studied in this work. Samples' chemical compositions in addition to their structural properties were analyzed to understand and compare oil migrations in the networks. Crystallized cocoa butter samples were placed in contact with a cream as a source of liquid oil. Using Magnetic Resonance Imaging, the movement of liquid oil into samples was investigated. The effects of minor differences in the cocoa butter chemical compositions on oil migrations rate are shown clearly. The highest effective diffusion coefficient was observed in the sample with the higher unsaturated fatty acids and phospholipids content. Although shearing at 250s -1 delayed oil migration in all the samples and a significantly lower diffusion coefficient was observed in the dynamic samples, the effects of chemical composition were still dominant. This study successfully highlighted that even minor differences in cocoa butter composition affect the network mass transfer phenomenon dramatically and that it is not easy to diminish these possessions by just crystallization processes. Published by Elsevier Ltd.

Conventional and accelerated-solvent extractions of green tea (camellia sinensis) for metabolomics-based chemometrics.

PubMed

Kellogg, Joshua J; Wallace, Emily D; Graf, Tyler N; Oberlies, Nicholas H; Cech, Nadja B

2017-10-25

Metabolomics has emerged as an important analytical technique for multiple applications. The value of information obtained from metabolomics analysis depends on the degree to which the entire metabolome is present and the reliability of sample treatment to ensure reproducibility across the study. The purpose of this study was to compare methods of preparing complex botanical extract samples prior to metabolomics profiling. Two extraction methodologies, accelerated solvent extraction and a conventional solvent maceration, were compared using commercial green tea [Camellia sinensis (L.) Kuntze (Theaceae)] products as a test case. The accelerated solvent protocol was first evaluated to ascertain critical factors influencing extraction using a D-optimal experimental design study. The accelerated solvent and conventional extraction methods yielded similar metabolite profiles for the green tea samples studied. The accelerated solvent extraction yielded higher total amounts of extracted catechins, was more reproducible, and required less active bench time to prepare the samples. This study demonstrates the effectiveness of accelerated solvent as an efficient methodology for metabolomics studies. Copyright © 2017. Published by Elsevier B.V.

Using Virtual Social Networks for Case Finding in Clinical Studies: An Experiment from Adolescence, Brain, Cognition, and Diabetes Study.

PubMed

Pourabbasi, Ata; Farzami, Jalal; Shirvani, Mahbubeh-Sadat Ebrahimnegad; Shams, Amir Hossein; Larijani, Bagher

2017-01-01

One of the main usages of social networks in clinical studies is facilitating the process of sampling and case finding for scientists. The main focus of this study is on comparing two different methods of sampling through phone calls and using social network, for study purposes. One of the researchers started calling 214 families of children with diabetes during 90 days. After this period, phone calls stopped, and the team started communicating with families through telegram, a virtual social network for 30 days. The number of children who participated in the study was evaluated. Although the telegram method was 60 days shorter than the phone call method, researchers found that the number of participants from telegram (17.6%) did not have any significant differences compared with the ones being phone called (12.9%). Using social networks can be suggested as a beneficial method for local researchers who look for easier sampling methods, winning their samples' trust, following up with the procedure, and an easy-access database.

Experimental aspect of solid-state nuclear magnetic resonance studies of biomaterials such as bones.

PubMed

Singh, Chandan; Rai, Ratan Kumar; Sinha, Neeraj

2013-01-01

Solid-state nuclear magnetic resonance (SSNMR) spectroscopy is increasingly becoming a popular technique to probe micro-structural details of biomaterial such as bone with pico-meter resolution. Due to high-resolution structural details probed by SSNMR methods, handling of bone samples and experimental protocol are very crucial aspects of study. We present here first report of the effect of various experimental protocols and handling methods of bone samples on measured SSNMR parameters. Various popular SSNMR experiments were performed on intact cortical bone sample collected from fresh animal, immediately after removal from animal systems, and results were compared with bone samples preserved in different conditions. We find that the best experimental conditions for SSNMR parameters of bones correspond to preservation at -20 °C and in 70% ethanol solution. Various other SSNMR parameters were compared corresponding to different experimental conditions. Our study has helped in finding best experimental protocol for SSNMR studies of bone. This study will be of further help in the application of SSNMR studies on large bone disease related animal model systems for statistically significant results. © 2013 Elsevier Inc. All rights reserved.

Comparative Study of the Effect of Sample Pretreatment and Extraction on the Determination of Flavonoids from Lemon (Citrus limon)

PubMed Central

Ledesma-Escobar, Carlos A.; Priego-Capote, Feliciano; Luque de Castro, María D.

2016-01-01

Background Flavonoids have shown to exert multiple beneficial effects on human health, being also appreciated by both food and pharmaceutical industries. Citrus fruits are a key source of flavonoids, thus promoting studies to obtain them. Characteristics of these studies are the discrepancies among sample pretreatments and among extraction methods, and also the scant number of comparative studies developed so far. Objective Evaluate the effect of both the sample pretreatment and the extraction method on the profile of flavonoids isolated from lemon. Results Extracts from fresh, lyophilized and air-dried samples obtained by shaking extraction (SE), ultrasound-assisted extraction (USAE), microwave-assisted extraction (MAE) and superheated liquid extraction (SHLE) were analyzed by LC–QTOF MS/MS, and 32 flavonoids were tentatively identified using MS/MS information. ANOVA applied to the data from fresh and dehydrated samples and from extraction by the different methods revealed that 26 and 32 flavonoids, respectively, were significant (p≤0.01). The pairwise comparison (Tukey HSD; p≤0.01) showed that lyophilized samples are more different from fresh samples than from air-dried samples; also, principal component analysis (PCA) showed a clear discrimination among sample pretreatment strategies and suggested that such differences are mainly created by the abundance of major flavonoids. On the other hand, pairwise comparison of extraction methods revealed that USAE and MAE provided quite similar extracts, being SHLE extracts different from the other two. In this case, PCA showed a clear discrimination among extraction methods, and their position in the scores plot suggests a lower abundance of flavonoids in the extracts from SHLE. In the two PCA the loadings plots revealed a trend to forming groups according to flavonoid aglycones. Conclusions The present study shows clear discrimination caused by both sample pretreatments and extraction methods. Under the studied conditions, liophilization provides extracts with higher amounts of flavonoids, and USAE is the best method for isolation of these compounds, followed by MAE and SE. On the contrary, the SHLE method was the less favorable to extract flavonoids from citrus owing to degradation. PMID:26807979

Slice sampling technique in Bayesian extreme of gold price modelling

NASA Astrophysics Data System (ADS)

Rostami, Mohammad; Adam, Mohd Bakri; Ibrahim, Noor Akma; Yahya, Mohamed Hisham

2013-09-01

In this paper, a simulation study of Bayesian extreme values by using Markov Chain Monte Carlo via slice sampling algorithm is implemented. We compared the accuracy of slice sampling with other methods for a Gumbel model. This study revealed that slice sampling algorithm offers more accurate and closer estimates with less RMSE than other methods . Finally we successfully employed this procedure to estimate the parameters of Malaysia extreme gold price from 2000 to 2011.

Comparability among four invertebrate sampling methods and two multimetric indexes, Fountain Creek Basin, Colorado, 2010–2012

USGS Publications Warehouse

Bruce, James F.; Roberts, James J.; Zuellig, Robert E.

2018-05-24

The U.S. Geological Survey (USGS), in cooperation with Colorado Springs City Engineering and Colorado Springs Utilities, analyzed previously collected invertebrate data to determine the comparability among four sampling methods and two versions (2010 and 2017) of the Colorado Benthic Macroinvertebrate Multimetric Index (MMI). For this study, annual macroinvertebrate samples were collected concurrently (in space and time) at 15 USGS surface-water gaging stations in the Fountain Creek Basin from 2010 to 2012 using four sampling methods. The USGS monitoring project in the basin uses two of the methods and the Colorado Department of Public Health and Environment recommends the other two. These methods belong to two distinct sample types, one that targets single habitats and one that targets multiple habitats. The study results indicate that there are significant differences in MMI values obtained from the single-habitat and multihabitat sample types but methods from each program within each sample type produced comparable values. This study also determined that MMI values calculated by different versions of the Colorado Benthic Macroinvertebrate MMI are indistinguishable. This indicates that the Colorado Department of Public Health and Environment methods are comparable with the USGS monitoring project methods for single-habitat and multihabitat sample types. This report discusses the direct application of the study results to inform the revision of the existing USGS monitoring project in the Fountain Creek Basin.

Increased anterior default-mode network homogeneity in first-episode, drug-naive major depressive disorder: A replication study.

PubMed

Guo, Wenbin; Cui, Xilong; Liu, Feng; Chen, Jindong; Xie, Guangrong; Wu, Renrong; Zhang, Zhikun; Chen, Huafu; Zhao, Jingping

2018-01-01

Abnormal default-mode network (DMN) homogeneity has been involved in the neurophysiology of major depressive disorder (MDD) with inconsistent findings. The inconsistency may be due to clinical and methodological variability, and the reproducibility of the findings is limited. The present study aimed to examine alterations of the DMN homogeneity in two independent samples of patients with first-episode, drug-naive MDD. The samples included 59 patients with MDD and 31 comparison subjects from Sample 1 and 29 patients with MDD and 24 comparison subjects from Sample 2. Network homogeneity (NH) was computed with an overlapping technique, which was employed to define brain regions with abnormal NH common to the MDD samples. Compared with comparison subjects, patients with MDD exhibited increased NH in an overlapped brain region of the left superior medial prefrontal cortex (MPFC). No correlations were found between abnormal NH and HAMD total/subscale scores in the patients of each sample and in the combined patients from both samples. This study is the first to examine alterations of DMN homogeneity in first-episode, drug-naive patients with MDD in two independent samples by using an overlapping technique. Patients with MDD exhibit increased NH in an overlapped region in the anterior DMN. The present study thus highlights the importance of the DMN in the neurophysiology of MDD. Copyright © 2017 Elsevier B.V. All rights reserved.

Factor Structure of the Internet Addiction Test in Online Gamers and Poker Players.

PubMed

Khazaal, Yasser; Achab, Sophia; Billieux, Joel; Thorens, Gabriel; Zullino, Daniele; Dufour, Magali; Rothen, Stéphane

2015-01-01

The Internet Addiction Test (IAT) is the most widely used questionnaire to screen for problematic Internet use. Nevertheless, its factorial structure is still debated, which complicates comparisons among existing studies. Most previous studies were performed with students or community samples despite the probability of there being more problematic Internet use among users of specific applications, such as online gaming or gambling. To assess the factorial structure of a modified version of the IAT that addresses specific applications, such as video games and online poker. Two adult samples-one sample of Internet gamers (n=920) and one sample of online poker players (n=214)-were recruited and completed an online version of the modified IAT. Both samples were split into two subsamples. Two principal component analyses (PCAs) followed by two confirmatory factor analyses (CFAs) were run separately. The results of principal component analysis indicated that a one-factor model fit the data well across both samples. In consideration of the weakness of some IAT items, a 17-item modified version of the IAT was proposed. This study assessed, for the first time, the factorial structure of a modified version of an Internet-administered IAT on a sample of Internet gamers and a sample of online poker players. The scale seems appropriate for the assessment of such online behaviors. Further studies on the modified 17-item IAT version are needed.

Impact of Processing Method on Recovery of Bacteria from Wipes Used in Biological Surface Sampling

PubMed Central

Olson, Nathan D.; Filliben, James J.; Morrow, Jayne B.

2012-01-01

Environmental sampling for microbiological contaminants is a key component of hygiene monitoring and risk characterization practices utilized across diverse fields of application. However, confidence in surface sampling results, both in the field and in controlled laboratory studies, has been undermined by large variation in sampling performance results. Sources of variation include controlled parameters, such as sampling materials and processing methods, which often differ among studies, as well as random and systematic errors; however, the relative contributions of these factors remain unclear. The objective of this study was to determine the relative impacts of sample processing methods, including extraction solution and physical dissociation method (vortexing and sonication), on recovery of Gram-positive (Bacillus cereus) and Gram-negative (Burkholderia thailandensis and Escherichia coli) bacteria from directly inoculated wipes. This work showed that target organism had the largest impact on extraction efficiency and recovery precision, as measured by traditional colony counts. The physical dissociation method (PDM) had negligible impact, while the effect of the extraction solution was organism dependent. Overall, however, extraction of organisms from wipes using phosphate-buffered saline with 0.04% Tween 80 (PBST) resulted in the highest mean recovery across all three organisms. The results from this study contribute to a better understanding of the factors that influence sampling performance, which is critical to the development of efficient and reliable sampling methodologies relevant to public health and biodefense. PMID:22706055

Development of a Standardized Approach for Environmental Microbiota Investigations related to Asthma Development in Children

PubMed Central

Fujimura, Kei E.; Rauch, Marcus; Matsui, Elizabeth; Iwai, Shoko; Calatroni, Agustin; Lynn, Henry; Mitchell, Herman; Johnson, Christine C.; Gern, James E.; Togias, Alkis; Boushey, Homer A.; Kennedy, Suzanne; Lynch, Susan V.

2013-01-01

Summary Standardized studies examining environmental microbial exposure in populations at risk for asthma are necessary to improve our understanding of the role this factor plays in disease development. Here we describe studies aimed at developing guidelines for high-resolution culture-independent microbiome profiling, using a phylogenetic microarray (PhyloChip), of house dust samples in a cohort collected as part of the NIH-funded Inner City Asthma Consortium (ICAC). We demonstrate that though extracted DNA concentrations varied across dust samples, the majority produced sufficient 16S rRNA to be profiled by the array. Comparison of array and 454-pyrosequencing performed in parallel on a subset of samples, illustrated that increasingly deeper sequencing efforts validated greater numbers of array-detected taxa. Community composition agreement across samples exhibited a hierarchy in concordance, with the highest level of agreement in replicate array profiles followed by samples collected from adjacent 1×1 m2 sites in the same room, adjacent sites with different sized sampling quadrants (1×1 and 2×2 m2), different sites within homes (living and bedroom) to lowest in living room samples collected from different homes. The guidelines for sample collection and processing in this pilot study extend beyond PhyloChip based studies of house-associated microbiota, and bear relevance for other microbiome profiling approaches such as next-generation sequencing. PMID:22975469

Arcobacter Isolation from Minced Beef Samples in Costa Rica.

PubMed

Córdoba-Calderón, Oscar; Redondo-Solano, Mauricio; Castro-Arias, Eduardo; Arias-EchandI, María Laura

2017-04-03

The presence of Arcobacter spp. in minced meat (including beef) samples has been well documented in different countries, with varying frequencies. Nevertheless, the only Latin American country reporting this bacterium in minced beef samples is Mexico, with a 28.8% frequency in 2003. Previous studies in Costa Rica have demonstrated the presence of Arcobacter species in samples taken from the poultry production chain, but still there are no studies performed in bovine meat. The aim of this study was to determine the frequency of this bacterium in 120 samples of minced beef acquired from the Central Valley region of Costa Rica and to describe the antibiotic sensitivity pattern of the isolates obtained. A total of 75 different Arcobacter strains were isolated from minced beef samples, for a final frequency of 48.3%. After species PCR identification, the strains were classified as A. butzleri (37.3%), A. cibarius (14.7%), A. thereius (12%), and Arcobacter spp. (36%). All samples were sensitive to gentamicin but were resistant to ampicillin, levofloxacin, nalidixic acid, and ciprofloxacin. The results obtained in this study show that the frequency of isolation of Arcobacter in minced beef samples is high and that there is a high resistance rate for antibiotics in common use. This suggests that Arcobacter represents a health risk for Costa Rica and that control measures should be developed to decrease its potential impact.

California GAMA program: ground-water quality data in the San Diego drainages hydrogeologic province, California, 2004

USGS Publications Warehouse

Wright, Michael T.; Belitz, Kenneth; Burton, Carmen A.

2005-01-01

Because of concerns over ground-water quality, the California State Water Resources Control Board (SWRCB), in collaboration with the U.S. Geological Survey and Lawrence Livermore National Laboratory, has implemented the Ground-Water Ambient Monitoring and Assessment (GAMA) Program. A primary objective of the program is to provide a current assessment of ground-water quality in areas where public supply wells are an important source of drinking water. The San Diego GAMA study unit was the first region of the state where an assessment of ground-water quality was implemented under the GAMA program. The San Diego GAMA study unit covers the entire San Diego Drainages hydrogeologic province, and is broken down into four distinct hydrogeologic study areas: the Temecula Valley study area, the Warner Valley study area, the Alluvial Basins study area, and the Hard Rock study area. A total of 58 ground-water samples were collected from public supply wells in the San Diego GAMA study unit: 19 wells were sampled in the Temecula Valley study area, 9 in the Warner Valley study area, 17 in the Alluvial Basins study area, and 13 in the Hard Rock study area. Over 350 chemical and microbial constituents and water-quality indicators were analyzed for in this study. However, only select wells were measured for all constituents and water-quality indicators. Results of analyses were calculated as detection frequencies by constituent classification and by individual constituents for the entire San Diego GAMA study unit and for the individual study areas. Additionally, concentrations of constituents that are routinely monitored were compared to maximum contaminant levels (MCL) and secondary maximum contaminant levels (SMCL). Concentrations of constituents classified as 'unregulated chemicals for which monitoring is required' (UCMR) were compared to the 'detection level for the purposes of reporting' (DLR). Eighteen of the 88 volatile organic compounds (VOCs) and gasoline oxygenates analyzed for were detected in ground-water samples. Twenty-eight wells sampled in the San Diego GAMA study had at least a single detection of VOCs or gasoline oxygenates. These constituents were most frequently detected in the Alluvial Basin study area (11 of 17 wells), and least frequently detected in the Warner Valley study area (one of nine wells). Trihalomethanes (THMs) were the most frequently detected class of VOCs (18 of 58 wells). The most frequently detected VOCs were chloroform (18 of 58 wells), bromodichloromethane (8 of 58 wells), and methyl tert-butyl ether (MTBE) (7 of 58 wells). Three VOCs were detected at concentrations greater than their MCLs. Tetrachloroethylene (PCE) and trichloroethylene (TCE) were detected in one well in the Hard Rock study area at concentrations of 9.75 and 7.27 micrograms per liter (?g/L), respectively; the MCL for these compounds is 5 ?g/L. MTBE was detected in one well in the Alluvial Basins study area at a concentration of 28.3 ?g/L; the MCL for MTBE is 13 ?g/L. Twenty-one of the 122 pesticides and pesticide degradates analyzed for were detected in ground-water samples. Pesticide or pesticide degradates were detected in 33 of 58 wells sampled, and were most frequently detected in the Temecula Valley study area wells (9 of 14 wells), and least frequently in the Warner Valley study area wells (3 of 9 wells). Herbicides were the most frequently detected class of pesticides (31 of 58 wells), and simazine was the most frequently detected compound (27 of 58 wells), followed by deethylatrazine (14 of 58 wells), prometon (10 of 58 wells), and atrazine (9 of 58 wells). None of the pesticides detected in ground-water samples had concentrations that exceeded MCLs. Eight waste-water indicator compounds were detected in ground-water samples. Twenty-one of 47 wells sampled for waste-water indicator compounds had at least a single detection. Waste-water indicator compounds were detected most frequently in the Allu

Isolation of Acanthamoeba Spp. from Drinking Waters in Several Hospitals of Iran

PubMed Central

Bagheri, HR; Shafiei, R; Shafiei, F; Sajjadi, SA

2010-01-01

Background Acanthamoeba is an opportunistic amphizoic protozoan found in different water sources including swimming pool as well as in sewage. The aim of this study was to investigate the prevalence of Acanthamoeba in tap-water samples in Iran. Method In this descriptive cross-sectional study, 94 samples of cold and warm tap-water were collected from different wards of hospitals in 13 cities of Iran in 2007–2008. Free residual chlorine, pH, and temperature of samples were measured. After filtration through multipore nylon membrane, samples were cultured on non-nutrient agar. Then we investigated existence of Acanthamoeba by reverse contrast phase microscope. Results Acanthamoeba was found in 45 samples (48%). Thirty-four and 11 positive samples were collected from cold and warm tap water, respectively. The samples belonged to the category of 20–30°C temperature with 0–2 ppm free residual chlorine and pH 6–7.4 showed the most coincidence to the positive cases. The greatest proportion of positive samples was obtained from Mashhad hospitals, while all samples collected from Arak and Semnan hospitals were negative. Conclusion considering the results of this study and the pathogenic role of this protozoan on patients with immunodeficiency, as well as capability of this microorganism in carrying other pathogens such as Legionella, further studies are needed. What is more important, potable water in hospitals should follow the procedure of treatment and sanitation, in order to prevent the relevant nosocomial infections. PMID:22347240

Association of classic lichen planus with human herpesvirus-7 infection.

PubMed

Nahidi, Yalda; Tayyebi Meibodi, Naser; Ghazvini, Kiarash; Esmaily, Habibollah; Esmaeelzadeh, Maryam

2017-01-01

Lichen planus is a mucocutaneous papulosquamous itchy disease with unknown etiology. A number of factors such as immune mechanisms, viral agents, and drugs have been implicated in pathogenesis of lichen planus. In recent years, several studies have indicated the role of viral agents in this disease, including human herpesvirus-7 (HHV-7). Studies have given contradictory results, which is why we decided to study the possible association between lichen planus with HHV-7. In this case-control study, which was conducted on 60 cutaneous classic lichen planus samples as well as 60 healthy control skin samples after matching the two groups in terms of gender and age, tissue samples of patients and controls were studied by real time polymerase chain reaction to detect for HHV-7. According to this study, HHV-7 DNA was found in 18 samples of the case group (30.0%) and in six (10.0%) of the control group (P = 0.006). The results of this study support the likely role of HHV-7 in pathogenesis of lichen planus. As an exogenous antigen, this virus may be involved in cellular immune-mediated destruction of keratinocytes. © 2016 The International Society of Dermatology.

Magnetic Properties and Microstructure of Some 2:17 High Temperature Magnets

NASA Astrophysics Data System (ADS)

Meng-Burany, X.; Hadjipanayis, George C.; Chui, S. T.

1997-03-01

Recent DOD demands for electric vehicle/plane applications require the use of magnets with operating temperatures > 450^circ C . Of existing high performance magnets, only the Sm(Co,Fe,Cu,Zr)z precipitation--hardened magnets have an operating temperature (300^circ C) which is close to the desired temperature and this makes these magnets potential candidates for further optimization studies. We have started a systematic study and modeling of the high temperature magnetic properties of several commercial magnets and other specially designed magnets supplied to us by Crucible Research. All the samples studied had a room temperature coercivity above 15 kOe. The coercivity was found to decrease with increasing temperature, with values of less than 4 kOe at 450^circ C , except for one sample which had a better temperature dependence with a coercivity above 6 kOe. TEM studies showed a cellular microstructure in all samples. The sample with better temperature properties had a smaller cell size but thicker cell walls. Lorentz electron microscopy studies are underway to image the domain walls and study their interaction with the cellular structure. The results of these studies will hopefully help us to understand the composition--microstructure--property relation in these magnets.

Synthesis and characterization of silicon nanorod on n-type porous silicon.

PubMed

Behzad, Kasra; Mat Yunus, Wan Mahmood; Bahrami, Afarin; Kharazmi, Alireza; Soltani, Nayereh

2016-03-20

This work reports a new method for growing semiconductor nanorods on a porous silicon substrate. After preparation of n-type porous silicon samples, a thin layer of gold was deposited on them. Gold deposited samples were annealed at different temperatures. The structural, thermal, and optical properties of the samples were studied using a field emission scanning electron microscope (FESEM), photoacoustic spectroscopy, and photoluminescence spectroscopy, respectively. FESEM analysis revealed that silicon nanorods of different sizes grew on the annealed samples. Thermal behavior of the samples was studied using photoacoustic spectroscopy. Photoluminescence spectroscopy showed that the emission peaks were degraded by gold deposition and attenuated for all samples by annealing.

A Trade Study and Metric for Penetration and Sampling Devices for Possible Use on the NASA 2003 and 2005 Mars Sample Return Missions

NASA Technical Reports Server (NTRS)

McConnell, Joshua B.

2000-01-01

The scientific exploration of Mars will require the collection and return of subterranean samples to Earth for examination. This necessitates the use of some type of device or devices that possesses the ability to effectively penetrate the Martian surface, collect suitable samples and return them to the surface in a manner consistent with imposed scientific constraints. The first opportunity for such a device will occur on the 2003 and 2005 Mars Sample Return missions, being performed by NASA. This paper reviews the work completed on the compilation of a database containing viable penetrating and sampling devices, the performance of a system level trade study comparing selected devices to a set of prescribed parameters and the employment of a metric for the evaluation and ranking of the traded penetration and sampling devices, with respect to possible usage on the 03 and 05 sample return missions. The trade study performed is based on a select set of scientific, engineering, programmatic and socio-political criterion. The use of a metric for the various penetration and sampling devices will act to expedite current and future device selection.

Influence of various water quality sampling strategies on load estimates for small streams

USGS Publications Warehouse

Robertson, Dale M.; Roerish, Eric D.

1999-01-01

Extensive streamflow and water quality data from eight small streams were systematically subsampled to represent various water‐quality sampling strategies. The subsampled data were then used to determine the accuracy and precision of annual load estimates generated by means of a regression approach (typically used for big rivers) and to determine the most effective sampling strategy for small streams. Estimation of annual loads by regression was imprecise regardless of the sampling strategy used; for the most effective strategy, median absolute errors were ∼30% based on the load estimated with an integration method and all available data, if a regression approach is used with daily average streamflow. The most effective sampling strategy depends on the length of the study. For 1‐year studies, fixed‐period monthly sampling supplemented by storm chasing was the most effective strategy. For studies of 2 or more years, fixed‐period semimonthly sampling resulted in not only the least biased but also the most precise loads. Additional high‐flow samples, typically collected to help define the relation between high streamflow and high loads, result in imprecise, overestimated annual loads if these samples are consistently collected early in high‐flow events.

Investigations on colour dependent photo induced microactuation effect of FSMA and proposing suitable mechanisms to control the effect

NASA Astrophysics Data System (ADS)

Bagchi, A.; Sarkar, S.; Mukhopadhyay, P. K.

2018-02-01

Three different coloured focused laser beams were used to study the photo induced microactuation effect found in some ferromagnetic shape memory alloys. Besides trying to uncover the basic causes of this unique and as yet unexplained effect, these studies are to help find other conditions to further characterize the effect for practical use. In this study some mechanisms have been proposed to control the amplitude of actuation of the sample. Control of the actuation of the FSMA sample both linearly with the help of a continuously variable neutral density filter as well periodically with the help of a linear polarizer was achieved. Statistical analysis of the experimental data was also done by applying ANOVA studies on the data to conclusively provide evidence in support of the relationship between the actuation of the sample and the various controlling factors. This study is expected to pave the way to implement this property of the sample in fabricating and operating useful micro-mechanical systems in the near future.

Sampling design trade-offs in occupancy studies with imperfect detection: examples and software

USGS Publications Warehouse

Bailey, L.L.; Hines, J.E.; Nichols, J.D.

2007-01-01

Researchers have used occupancy, or probability of occupancy, as a response or state variable in a variety of studies (e.g., habitat modeling), and occupancy is increasingly favored by numerous state, federal, and international agencies engaged in monitoring programs. Recent advances in estimation methods have emphasized that reliable inferences can be made from these types of studies if detection and occupancy probabilities are simultaneously estimated. The need for temporal replication at sampled sites to estimate detection probability creates a trade-off between spatial replication (number of sample sites distributed within the area of interest/inference) and temporal replication (number of repeated surveys at each site). Here, we discuss a suite of questions commonly encountered during the design phase of occupancy studies, and we describe software (program GENPRES) developed to allow investigators to easily explore design trade-offs focused on particularities of their study system and sampling limitations. We illustrate the utility of program GENPRES using an amphibian example from Greater Yellowstone National Park, USA.

Investigations on colour dependent photo induced microactuation effect of FSMA and proposing suitable mechanisms to control the effect

NASA Astrophysics Data System (ADS)

Bagchi, A.; Sarkar, S.; Mukhopadhyay, P. K.

2018-07-01

Three different coloured focused laser beams were used to study the photo induced microactuation effect found in some ferromagnetic shape memory alloys. Besides trying to uncover the basic causes of this unique and as yet unexplained effect, these studies are to help find other conditions to further characterize the effect for practical use. In this study some mechanisms have been proposed to control the amplitude of actuation of the sample. Control of the actuation of the FSMA sample both linearly with the help of a continuously variable neutral density filter as well periodically with the help of a linear polarizer was achieved. Statistical analysis of the experimental data was also done by applying ANOVA studies on the data to conclusively provide evidence in support of the relationship between the actuation of the sample and the various controlling factors. This study is expected to pave the way to implement this property of the sample in fabricating and operating useful micro-mechanical systems in the near future.

Laboratory Studies on Surface Sampling of Bacillus anthracis Contamination: Summary, Gaps, and Recommendations

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

Piepel, Gregory F.; Amidan, Brett G.; Hu, Rebecca

2011-11-28

This report summarizes previous laboratory studies to characterize the performance of methods for collecting, storing/transporting, processing, and analyzing samples from surfaces contaminated by Bacillus anthracis or related surrogates. The focus is on plate culture and count estimates of surface contamination for swab, wipe, and vacuum samples of porous and nonporous surfaces. Summaries of the previous studies and their results were assessed to identify gaps in information needed as inputs to calculate key parameters critical to risk management in biothreat incidents. One key parameter is the number of samples needed to make characterization or clearance decisions with specified statistical confidence. Othermore » key parameters include the ability to calculate, following contamination incidents, the (1) estimates of Bacillus anthracis contamination, as well as the bias and uncertainties in the estimates, and (2) confidence in characterization and clearance decisions for contaminated or decontaminated buildings. Gaps in knowledge and understanding identified during the summary of the studies are discussed and recommendations are given for future studies.« less

Pornography consumption and non-marital sexual behaviour in a sample of young Indonesian university students.

PubMed

Hald, Gert Martin; Mulya, Teguh Wijaya

2013-01-01

Using a sample of Indonesian university students and a cross sectional design, this study investigated prevalence rates and patterns of pornography consumption in Indonesia, a religious, sexually conservative, Muslim-majority nation with strict anti-pornography laws. Further, the association between pornography consumption and common non-marital sexual behaviours was explored. The study found that in this sample, pornography is as widely and readily consumed as in comparable international studies predominantly utilising Western background samples from more sexually liberal and less religious countries with very few laws on pornography. Gender differences in patterns of pornography consumption were pronounced and comparable with findings in international counterpart studies. For men only, pornography consumption was found to significantly predict common sexual behaviours in non-marital relations. The study is the first to provide insights into prevalence rates and patterns of pornography consumption and its association with common non-marital sexual behaviours in a sexually conservative, Muslim-majority nation with strict anti-pornography laws.

Prevalence of urinary tract infection (UTI) in sequential acutely unwell children presenting in primary care: exploratory study.

PubMed

O'Brien, Kathryn; Stanton, Naomi; Edwards, Adrian; Hood, Kerenza; Butler, Christopher C

2011-03-01

Due to the non-specific nature of symptoms of UTI in children and low levels of urine sampling, the prevalence of UTI amongst acutely ill children in primary care is unknown. To undertake an exploratory study of acutely ill children consulting in primary care, determine the feasibility of obtaining urine samples, and describe presenting symptoms and signs, and the proportion with UTI. Exploratory, observational study. Four general practices in South Wales. A total of 99 sequential attendees with acute illness aged less than five years. UTI defined by >10(5) organisms/ml on laboratory culture of urine. Urine samples were obtained in 75 (76%) children. Three (4%) met microbiological criteria for UTI. GPs indicated they would not normally have obtained urine samples in any of these three children. However, all had received antibiotics for suspected alternative infections. Urine sample collection is feasible from the majority of acutely ill children in primary care, including infants. Some cases of UTI may be missed if children thought to have an alternative site of infection are excluded from urine sampling. A larger study is needed to more accurately determine the prevalence of UTI in children consulting with acute illness in primary care, and to explore which symptoms and signs might help clinicians effectively target urine sampling.

Genetic Association of MPPED2 and ACTN2 with Dental Caries

PubMed Central

Stanley, B.O.C.; Feingold, E.; Cooper, M.; Vanyukov, M.M.; Maher, B.S.; Slayton, R.L.; Willing, M.C.; Reis, S.E.; McNeil, D.W.; Crout, R.J.; Weyant, R.J.; Levy, S.M.; Vieira, A.R.; Marazita, M.L.; Shaffer, J.R.

2014-01-01

The first genome-wide association study of dental caries focused on primary teeth in children aged 3 to 12 yr and nominated several novel genes: ACTN2, EDARADD, EPHA7, LPO, MPPED2, MTR, and ZMPSTE24. Here we interrogated 156 single-nucleotide polymorphisms (SNPs) within these candidate genes for evidence of association with dental caries experience in 13 race- and age-stratified samples from 6 independent studies (n = 3600). Analysis was performed separately for each sample, and results were combined across samples via meta-analysis. MPPED2 was significantly associated with caries via meta-analysis across the 5 childhood samples, with 4 SNPs showing significant associations after gene-wise adjustment for multiple comparisons (p < .0026). These results corroborate the previous genome-wide association study, although the functional role of MPPED2 in caries etiology remains unknown. ACTN2 also showed significant association via meta-analysis across childhood samples (p = .0014). Moreover, in adults, genetic association was observed for ACTN2 SNPs in individual samples (p < .0025), but no single SNP was significant via meta-analysis across all 8 adult samples. Given its compelling biological role in organizing ameloblasts during amelogenesis, this study strengthens the hypothesis that ACTN2 influences caries risk. Results for the other candidate genes neither proved nor precluded their associations with dental caries. PMID:24810274

Comparison of ELISA and Microscopy for detection of Cryptosporidium in stool

PubMed Central

Sharma, Madhu; Chaudhary, Uma; Yadav, Aparna

2014-01-01

Background: Cryptosporidiosis, a diarrheal disease caused by the protozoan parasite Cryptosporidium spp. has become recognized as one of the most common causes of water borne diseases in humans. Aims and Objectives: To compare the sensitivity of ELISA and Microscopy for detection of Cryptosporidium in stool samples Materials and Methods: The study was conducted in the Department of Microbiology of PT. B.D. Sharma PGIMS Rohtak, between January 2011 to june 2011 on 50 stool samples, which were processed for detection of cryptosporidial antigen by ELISA and detection of cysts by microscopy (Modified Ziehl and Nelsen staining). Study and Design: This was a prospective study conducted in the Department of Microbiology in PT. BD Sharma, PGIMS, Rohtak, India. Result: Out of total, 50 stool samples eighteen (36%) samples were found positive for Cryptosporidium cysts by microscopy in comparison to 3(6%) stool samples which were found positive for cryptosporidial antigen by ELISA. Samples found positive with ELISA were also positive with microscopy. Sensitivity, specificity, positive predictive value and negative predictive value for ELISA was 16.7%, 100%, 100% and 68% respectively. Conclusion: The study concludes that stool microscopic Modified acid fast staining is more sensitive method than ELISA for detection of Cryptosporidium in stool samples but the specificity of ELISA was more than microscopy. PMID:25584216

Prediction of reinforced concrete strength by ultrasonic velocities

NASA Astrophysics Data System (ADS)

Sabbağ, Nevbahar; Uyanık, Osman

2017-06-01

This study was aimed to determine the strength of the reinforced concrete and to reveal the reinforcement effect on the concrete strength by Ultrasonic P and S wave velocities. Studies were conducted with prepared 9 different concrete designs of showing low, medium and high strength features. 4 kinds of cubic samples which unreinforced and including 10, 14 or 20 mm diameter reinforcement were prepared for these designs. Studies were carried out on total 324 samples including 9 samples for each design of these 4 kinds. The prepared samples of these designs were subjected to water curing. On some days of the 90-day period, P and S wave measurements were repeated to reveal the changes in seismic velocities of samples depending on whether reinforced or unreinforced of samples and diameter of reinforcement. Besides, comparisons were done by performing uniaxial compressive strength test with crushing of 3 samples on 7th, 28th and 90th days. As a result of studies and evaluations, it was seen that values of seismic velocities and uniaxial compressive strength increased depending on reinforcement and diameter of reinforcement in low strength concretes. However, while the seismic velocities were not markedly affected from reinforcement or reinforcement diameter in high strength concrete, uniaxial compressive strength values were negatively affected.

Does Nosema ceranae Wipe Out Nosema apis in Turkey?

PubMed

Ivgin Tunca, Rahşan; Oskay, Devrim; Gosterit, Ayhan; Tekin, Olgay Kaan

2016-01-01

The aim of this study was to determine the prevalence of the Nosema ceranae and Nosema apis among apiaries using both spore counts and multiplex PCR and the replacement of N. apis by N. ceranae in some regions of Turkey. A hundred honey bee samples were collected from 99 apiaries in 11 different locations in 2011-2012 in Turkey. Nosema infection degree from collected samples was determined using light microscope and molecular detection of Nosema spp. ( N. ceranae and N. apis ) was performed using specific primers by multiplex PCR. N. ceranae was only found spores in sampling areas using molecular diagnosis. N. apis was not detected in whole sampling areas using both techniques. There are no Nosema spores detected in Konya one location using two techniques. The nucleotide sequences from amplification products of the Nosema infested honeybee samples were (98%) identical with the sequence of N. ceranae for many countries deposited in the GenBank database in this study. The present study illustrated that N. ceranae is the only spores for sampled areas in 2011-2012. The study could also indicate that N. ceranae has been replaced instead of N . apis in Turkey. In addition, the prevalence of N. ceranae and two microsporodia spores effects on honey bee colonies in Turkey were needed to determine with intensive sampling, periodically.

Small sample sizes in the study of ontogenetic allometry; implications for palaeobiology

PubMed Central

Vavrek, Matthew J.

2015-01-01

Quantitative morphometric analyses, particularly ontogenetic allometry, are common methods used in quantifying shape, and changes therein, in both extinct and extant organisms. Due to incompleteness and the potential for restricted sample sizes in the fossil record, palaeobiological analyses of allometry may encounter higher rates of error. Differences in sample size between fossil and extant studies and any resulting effects on allometric analyses have not been thoroughly investigated, and a logical lower threshold to sample size is not clear. Here we show that studies based on fossil datasets have smaller sample sizes than those based on extant taxa. A similar pattern between vertebrates and invertebrates indicates this is not a problem unique to either group, but common to both. We investigate the relationship between sample size, ontogenetic allometric relationship and statistical power using an empirical dataset of skull measurements of modern Alligator mississippiensis. Across a variety of subsampling techniques, used to simulate different taphonomic and/or sampling effects, smaller sample sizes gave less reliable and more variable results, often with the result that allometric relationships will go undetected due to Type II error (failure to reject the null hypothesis). This may result in a false impression of fewer instances of positive/negative allometric growth in fossils compared to living organisms. These limitations are not restricted to fossil data and are equally applicable to allometric analyses of rare extant taxa. No mathematically derived minimum sample size for ontogenetic allometric studies is found; rather results of isometry (but not necessarily allometry) should not be viewed with confidence at small sample sizes. PMID:25780770

[Anaerobic bacteria isolated from patients with suspected anaerobic infections].

PubMed

Ercis, Serpil; Tunçkanat, Ferda; Hasçelik, Gülşen

2005-10-01

The study involved 394 clinical samples sent to the Clinical Microbiology Laboratory of Hacettepe University Adult Hospital between January 1997 and May 2004 for anaerobic cultivation. Since multiple cultures from the same clinical samples of the same patient were excluded, the study was carried on 367 samples. The anaerobic cultures were performed in anaerobic jar using AnaeroGen kits (Oxoid, Basingstoke, U.K.) or GENbox (bioMérieux, Lyon, France). The isolates were identified by both classical methods and "BBL Crystal System" (Becton Dickinson, U.S.A.). While no growth was detected in 120 (32.7%) of the clinical samples studied, in 144 samples (39.2%) only aerobes, in 28 (7.6%) only anaerobes and in 75 (20.5%) of the samples both aerobes and anaerobes were isolated. The number of the anaerobic isolates was 217 from 103 samples with anaerobic growth. Of these 103 samples 15 showed single bacterial growth whereas in 88 samples multiple bacterial isolates were detected. Anaerobic isolates consisted of 92 Gram negative bacilli (Bacteroides spp. 50, Prevotella spp. 14, Porphyromonas spp. 10, Fusobacterium spp. 7, Tisierella spp. 2, unidentified 9), 57 Gram positive bacilli (Clostridium spp.17, Propionibacterium spp. 16, Lactobacillus spp. 8, Actinomyces spp. 5, Eubacterium spp. 2, Bifidobacterium adolescentis 1, Mobiluncus mulieris 1, unidentified nonspore forming rods 7), 61 Gram positive cocci (anaerobic cocci 44, microaerophilic cocci 17), and 7 Gram negative cocci (Veillonella spp.). In conclusion, in the samples studied with prediagnosis of anaerobic infection, Bacteroides spp. (23%) were the most common bacteria followed by anaerobic Gram positive cocci (20.3%) and Clostridium spp (7.8%).

[Methodological Aspects of the Sampling Design for the 2015 National Mental Health Survey].

PubMed

Rodríguez, Nelcy; Rodríguez, Viviana Alejandra; Ramírez, Eugenia; Cediel, Sandra; Gil, Fabián; Rondón, Martín Alonso

2016-12-01

The WHO has encouraged the development, implementation and evaluation of policies related to mental health all over the world. In Colombia, within this framework and promoted by the Ministry of Health and Social Protection, as well as being supported by Colciencias, the fourth National Mental Health Survey (NMHST) was conducted using a observational cross sectional study. According to the context and following the guidelines and sampling design, a summary of the methodology used for this sampling process is presented. The fourth NMHST used the Homes Master Sample for Studies in Health from the National System of Studies and Population Surveys for Health to calculate its sample. This Master Sample was developed and implemented in the year 2013 by the Ministry of Social Protection. This study included non-institutionalised civilian population divided into four age groups: children 7-11 years, adolescent 12-17 years, 18-44 years and 44 years old or older. The sample size calculation was based on the reported prevalences in other studies for the outcomes of mental disorders, depression, suicide, associated morbidity, and alcohol use. A probabilistic, cluster, stratified and multistage selection process was used. Expansions factors to the total population were calculated. A total of 15,351 completed surveys were collected and were distributed according to the age groups: 2727, 7-11 years, 1754, 12-17 years, 5889, 18-44 years, and 4981, ≥45 years. All the surveys were distributed in five regions: Atlantic, Oriental, Bogotá, Central and Pacific. A sufficient number of surveys were collected in this study to obtain a more precise approximation of the mental problems and disorders at the regional and national level. Copyright © 2016 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

Neural correlates of social exclusion across ages: A coordinate-based meta-analysis of functional MRI studies.

PubMed

Vijayakumar, Nandita; Cheng, Theresa W; Pfeifer, Jennifer H

2017-06-01

Given the recent surge in functional neuroimaging studies on social exclusion, the current study employed activation likelihood estimation (ALE) based meta-analyses to identify brain regions that have consistently been implicated across different experimental paradigms used to investigate exclusion. We also examined the neural correlates underlying Cyberball, the most commonly used paradigm to study exclusion, as well as differences in exclusion-related activation between developing (7-18 years of age, from pre-adolescence up to late adolescence) and emerging adult (broadly defined as undergraduates, including late adolescence and young adulthood) samples. Results revealed involvement of the bilateral medial prefrontal and posterior cingulate cortices, right precuneus and left ventrolateral prefrontal cortex across the different paradigms used to examine social exclusion; similar activation patterns were identified when restricting the analysis to Cyberball studies. Investigations into age-related effects revealed that ventrolateral prefrontal activations identified in the full sample were driven by (i.e. present in) developmental samples, while medial prefrontal activations were driven by emerging adult samples. In addition, the right ventral striatum was implicated in exclusion, but only in developmental samples. Subtraction analysis revealed significantly greater activation likelihood in striatal and ventrolateral prefrontal clusters in the developmental samples as compared to emerging adults, though the opposite contrast failed to identify any significant regions. Findings integrate the knowledge accrued from functional neuroimaging studies on social exclusion to date, highlighting involvement of lateral prefrontal regions implicated in regulation and midline structures involved in social cognitive and self-evaluative processes across experimental paradigms and ages, as well as limbic structures in developing samples specifically. Copyright © 2017 Elsevier Inc. All rights reserved.

Statistical inferences for data from studies conducted with an aggregated multivariate outcome-dependent sample design.

PubMed

Lu, Tsui-Shan; Longnecker, Matthew P; Zhou, Haibo

2017-03-15

Outcome-dependent sampling (ODS) scheme is a cost-effective sampling scheme where one observes the exposure with a probability that depends on the outcome. The well-known such design is the case-control design for binary response, the case-cohort design for the failure time data, and the general ODS design for a continuous response. While substantial work has been carried out for the univariate response case, statistical inference and design for the ODS with multivariate cases remain under-developed. Motivated by the need in biological studies for taking the advantage of the available responses for subjects in a cluster, we propose a multivariate outcome-dependent sampling (multivariate-ODS) design that is based on a general selection of the continuous responses within a cluster. The proposed inference procedure for the multivariate-ODS design is semiparametric where all the underlying distributions of covariates are modeled nonparametrically using the empirical likelihood methods. We show that the proposed estimator is consistent and developed the asymptotically normality properties. Simulation studies show that the proposed estimator is more efficient than the estimator obtained using only the simple-random-sample portion of the multivariate-ODS or the estimator from a simple random sample with the same sample size. The multivariate-ODS design together with the proposed estimator provides an approach to further improve study efficiency for a given fixed study budget. We illustrate the proposed design and estimator with an analysis of association of polychlorinated biphenyl exposure to hearing loss in children born to the Collaborative Perinatal Study. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

A psychometric study of the Fear of Sleep Inventory-Short Form (FoSI-SF).

PubMed

Pruiksma, Kristi E; Taylor, Daniel J; Ruggero, Camilo; Boals, Adriel; Davis, Joanne L; Cranston, Christopher; DeViva, Jason C; Zayfert, Claudia

2014-05-15

Fear of sleep may play a significant role in sleep disturbances in individuals with posttraumatic stress disorder (PTSD). This report describes a psychometric study of the Fear of Sleep Inventory (FoSI), which was developed to measure this construct. The psychometric properties of the FoSI were examined in a non-clinical sample of 292 college students (Study I) and in a clinical sample of 67 trauma-exposed adults experiencing chronic nightmares (Study II). Data on the 23 items of the FoSI were subjected to exploratory factor analyses (EFA) to identify items uniquely assessing fear of sleep. Next, reliability and validity of a 13-item version of the FoSI was examined in both samples. A 13-item Short-Form version (FoSI-SF) was identified as having a clear 2-factor structure with high internal consistency in both the non-clinical (α = 0.76-0.94) and clinical (α = 0.88-0.91) samples. Both studies demonstrated good convergent validity with measures of PTSD (0.48-0.61) and insomnia (0.39-0.48) and discriminant validity with a measure of sleep hygiene (0.19-0.27). The total score on the FoSI-SF was significantly higher in the clinical sample (mean = 17.90, SD = 12.56) than in the non-clinical sample (mean = 4.80, SD = 7.72); t(357) = 8.85 p < 0.001. Although all items are recommended for clinical purposes, the data support the use of the 13-item FoSI-SF for research purposes. Replication of the factor structure in clinical samples is needed. Results are discussed in terms of limitations of this study and directions for further research.

Characterization of pesticide exposure in a sample of pregnant women in Ecuador

PubMed Central

Handal, Alexis J.; Hund, Lauren; Páez, Maritza; Bear, Samantha; Greenberg, Carolyn; Fenske, Richard A.; Barr, Dana Boyd

2015-01-01

Background Few studies have detailed the prenatal pesticide exposure levels of women employed in or residing near large-scale agricultural industries. This study reports pesticide metabolite levels during and shortly after pregnancy in a pilot study of workers in Ecuador. Methods Urine samples were collected for 16 rose workers and 10 non-agricultural workers enrolled into the study in early pregnancy. We measured six nonspecific organophosphate dialkylphosphate (DAP) pesticide metabolites, two alkylenebis-dithiocarbamate pesticide metabolites (ethylene thiourea [ETU] and propylene thiourea [PTU]), 3,5,6-trichloro-2-pyridinol [TCPy], malathion dicarboxylic acid, and two pyrethroid metabolites (2,2-dimethylcyclopropanecarboxylic acid and 3-phenooxybenzoic acid). Results We collected 141 urine samples (mean: 5.4 per woman). We observed high detection frequencies for five DAP metabolites and ETU, PTU, and TCPy. We report elevated levels of ETU in the entire sample (median 4.24 ng/mL, IQR 2.23, 7.18), suggesting other possible non-occupational pathways of exposure. We found no statistical differences in pesticide levels by current employment status, though the highest pesticide levels were among rose workers. We observed within-woman correlation in TCPy and PTU levels, but not in ETU or DAP levels. Conclusions The present study is the first to characterize prenatal pesticide exposure levels among working women in Ecuador. Limitations include a small sample size and use of a convenience sample. Strengths include a longitudinal design and multiple urine samples per woman. Results provide an initial characterization of prenatal pesticide exposure levels and how these levels vary over pregnancy in a community impacted by agricultural industry and will inform further studies in the region. PMID:26311023

Does substance misuse moderate the relationship between criminal thinking and recidivism?

PubMed Central

Caudy, Michael S.; Folk, Johanna B.; Stuewig, Jeffrey B.; Wooditch, Alese; Martinez, Andres; Maass, Stephanie; Tangney, June P.; Taxman, Faye S.

2014-01-01

Purpose Some differential intervention frameworks contend that substance use is less robustly related to recidivism outcomes than other criminogenic needs such as criminal thinking. The current study tested the hypothesis that substance use disorder severity moderates the relationship between criminal thinking and recidivism. Methods The study utilized two independent criminal justice samples. Study 1 included 226 drug-involved probationers. Study 2 included 337 jail inmates with varying levels of substance use disorder severity. Logistic regression was employed to test the main and interactive effects of criminal thinking and substance use on multiple dichotomous indicators of recidivism. Results Bivariate analyses revealed a significant correlation between criminal thinking and recidivism in the jail sample (r = .18, p < .05) but no significant relationship in the probation sample. Logistic regressions revealed that SUD symptoms moderated the relationship between criminal thinking and recidivism in the jail-based sample (B = −.58, p < .05). A significant moderation effect was not observed in the probation sample. Conclusions Study findings indicate that substance use disorder symptoms moderate the strength of the association between criminal thinking and recidivism. These findings demonstrate the need for further research into the interaction between various dynamic risk factors. PMID:25598559

Dynamic microbial populations along the Cuyahoga River

PubMed Central

Craine, Joseph; Hester, James; Shalkhauser, Amanda; Chan, Ernest R.; Logue, Kyle; Small, Scott; Serre, David

2017-01-01

The study of the microbial communities has gained traction in recent years with the advent of next-generation sequencing with, or without, PCR-based amplification of the 16S ribosomal RNA region. Such studies have been applied to topics as diverse as human health and environmental ecology. Fewer studies have investigated taxa outside of bacteria, however. We present here data demonstrating the utility of studying taxa outside of bacteria including algae, diatoms, archaea and fungi. Here, we show how location along the Cuyahoga River as well as a transient rainfall event heavily influence the microbial composition. Our data reveal how individual OTUs vary between samples and how the patterns of OTU abundance can accurately predict sampling location. The clustering of samples reveals that these taxa are all sensitive to water conditions in unique ways and demonstrate that, for our dataset, algae was most distinctive between sample groups, surpassing bacteria. Diversity between sampling sites could allow studies investigating pollution or water quality to identify marker OTUs or patterns of OTU abundance as indicators to assess environmental conditions or the impact of human activity. We also directly compare data derived from primers amplifying distinct taxa and show that taxa besides bacteria are excellent indicators of water condition. PMID:29049324

Mechanical Properties of Lightweight Concrete Using Recycled Cement-Sand Brick as Coarse Aggregates Replacement

NASA Astrophysics Data System (ADS)

Joohari, Ilya; Farhani Ishak, Nor; Amin, Norliyati Mohd

2018-03-01

This paper presents the result of replacing natural course aggregate with recycled cement-sand brick (CSB) towards the mechanical properties of concrete. Natural aggregates were used in this study as a control sample to compare with recycled coarse aggregates. This study was also carried to determine the optimum proportion of coarse aggregates replacement to produce lightweight concrete. Besides, this study was conducted to observe the crack and its behaviour development during the mechanical testing. Through this study, four types of concrete mixed were prepared, which were the control sample, 25%, 50% and 75% replacement of CSB. The test conducted to determine the effectiveness of recycled CSB as coarse aggregates replacement in this study were slump test, density measurement, compression test, and flexural test and. The strength of concrete was tested at 7 days and 28 days of curing. From the results obtained, the optimum proportion which produced the highest strength is 25% replacement of recycled CSB. The compressive and flexural strength has decreased by 10%-12% and 4%-34% respectively compared to the control sample. The presence of recycled coarse aggregates in sample has decreased the density of concrete by 0.8%-3% compared to the control sample.

Detection of Candida species by nested PCR method in one-humped camels (Camelus dromedarius).

PubMed

Parin, Ugur; Erbas, Goksel; Kirkan, Sukru; Savasan, Serap; Tugba Yuksel, H; Balat, Gamze

2018-02-01

Systemic fungal diseases are the infections caused by false treatment protocols and generally are not taken into consideration especially in the veterinary field. One-humped camels are found in the western side of the Aegean region of our country and bred for wrestling. The aim of this study is the application of diagnosing systemic fungi infection from camel blood samples by the PCR method. In this study, specific primers for DNA topoisomerase II gene sequences were used. As a result, a systemic fungal infection was detected by the nested PCR method from 10 (20%) out of 50 DNA samples taken from camels located on the western side of the Aegean region. In this study, 3 (30%) samples were identified as Candida albicans, 3 (30%) samples were identified as C. glabrata, and 4 (40%) samples were identified as C. parapsilosis. In conclusion, the 20% positive systemic fungal infection rate in one-humped camels observed in the present study showed that the systemic fungal infections are not taken into considerations in veterinary medicine. Further studies are suggested in order to obtain and to maintain extensive data for systemic fungal diseases in our country for one-humped camels.

Moment-to-Moment Transfer of Positive Emotions in Daily Life Predicts Future Course of Depression in Both General Population and Patient Samples

PubMed Central

Höhn, Petra; Menne-Lothmann, Claudia; Peeters, Frenk; Nicolson, Nancy A.; Jacobs, Nele; Derom, Catherine; Thiery, Evert; van Os, Jim; Wichers, Marieke

2013-01-01

Objective Positive affect (PA) is closely linked to prevention of, and recovery from, depression. Previous studies have investigated PA reactivity to pleasant situations with respect to its protective properties in relation to mood disorder. The purpose of this study was to examine, and replicate, whether moment-to-moment transfer of PA in daily life (PA persistence) is relevant to the prediction of future course of depression. Method Individuals from three different studies (one general population sample (n=540), and two patient samples (n=43 and n=50) with matching controls (n=39 and n=21, respectively)) participated in an Experience Sampling Method (ESM) study. Time-lagged multilevel analyses were used to assess the degree of transfer (or persistence) of momentary positive affective states over time, in relation to naturalistic outcome (study 1) or treatment outcome (studies 2 and 3). Depressive symptoms were measured using the Symptom Checklist (SCL-90R) in sample 1 and the Hamilton Depression Rating Scale (HDRS) in samples 2 and 3. Results In study 1, participants with greater momentary PA persistence were less likely to show depressive symptoms at follow-up. In study 2, patients were more likely to respond to treatment if they displayed greater momentary PA persistence, particularly in those with recurrent depression. In study 3, patients with greater momentary PA persistence were similarly more likely to respond to treatment, especially when treated with imipramine rather than placebo. Conclusion The ability to transfer PA from one moment to the next is an important factor in the prevention of and recovery from depressive symptoms. Patients with recurrent depression and those who receive antidepressants rather than placebo may benefit most from this effect. The results suggest that treatment-induced improvement in depression is mediated by increased levels of momentary transfer of PA in daily life, acquisition of which may be contingent on duration of exposure to depressive experience. PMID:24086602

GY SAMPLING THEORY IN ENVIRONMENTAL STUDIES 1: ASSESSING SOIL SPLITTING PROTOCOLS

EPA Science Inventory

Five soil sample splitting methods (riffle splitting, paper cone riffle splitting, fractional shoveling, coning and quartering, and grab sampling) were evaluated with synthetic samples to verify Pierre Gy sampling theory expectations. Individually prepared samples consisting of l...

Sampling in ecology and evolution - bridging the gap between theory and practice

USGS Publications Warehouse

Albert, C.H.; Yoccoz, N.G.; Edwards, T.C.; Graham, C.H.; Zimmermann, N.E.; Thuiller, W.

2010-01-01

Sampling is a key issue for answering most ecological and evolutionary questions. The importance of developing a rigorous sampling design tailored to specific questions has already been discussed in the ecological and sampling literature and has provided useful tools and recommendations to sample and analyse ecological data. However, sampling issues are often difficult to overcome in ecological studies due to apparent inconsistencies between theory and practice, often leading to the implementation of simplified sampling designs that suffer from unknown biases. Moreover, we believe that classical sampling principles which are based on estimation of means and variances are insufficient to fully address many ecological questions that rely on estimating relationships between a response and a set of predictor variables over time and space. Our objective is thus to highlight the importance of selecting an appropriate sampling space and an appropriate sampling design. We also emphasize the importance of using prior knowledge of the study system to estimate models or complex parameters and thus better understand ecological patterns and processes generating these patterns. Using a semi-virtual simulation study as an illustration we reveal how the selection of the space (e.g. geographic, climatic), in which the sampling is designed, influences the patterns that can be ultimately detected. We also demonstrate the inefficiency of common sampling designs to reveal response curves between ecological variables and climatic gradients. Further, we show that response-surface methodology, which has rarely been used in ecology, is much more efficient than more traditional methods. Finally, we discuss the use of prior knowledge, simulation studies and model-based designs in defining appropriate sampling designs. We conclude by a call for development of methods to unbiasedly estimate nonlinear ecologically relevant parameters, in order to make inferences while fulfilling requirements of both sampling theory and field work logistics. ?? 2010 The Authors.

The Five-Factor Model of Personality and Its Relationship to Cognitive Style (Rush and Prudence) and Academic Achievement among a Sample of Students

ERIC Educational Resources Information Center

Barakat, Asia; Othman, Afaf

2015-01-01

The present study aims to identify the relationship between the five-factor model of personality and its relationship to cognitive style (rush and prudence) and academic achievement among a sample of students. The study is based on descriptive approach for studying the relationship between the variables of the study, results and analysis. The…

The Level of High-Order Thinking and Its Relation to Quality of Life among Students at Ajloun University College

ERIC Educational Resources Information Center

Al Rabadi, Wail Minwer; Salem, Rifqa Khleif

2018-01-01

The study was designed to identify the effect of high-order thinking on the quality of life among Ajloun University students. The study used the associative method. The randomly selected sample consisted of 147 students from Ajloun University College. The study used two tools: The two measures were applied to the sample of the current study after…

Factors Influence the Digital Media Teaching of Primary School Teachers in a Flipped Class: A Taiwan Case Study

ERIC Educational Resources Information Center

Cheng, Yung-Hsun; Weng, Chia-Wen

2017-01-01

The current study focuses on the key roles that affect the success of a flipped classroom. The research was conducted with a questionnaire survey created from a study of literature review. Out of a total of 441 samples, 424 valid samples (96.14%) from teachers have been received. The study key conclusions are as follows: (1) a principal leadership…

Meta-analysis with missing study-level sample variance data.

PubMed

Chowdhry, Amit K; Dworkin, Robert H; McDermott, Michael P

2016-07-30

We consider a study-level meta-analysis with a normally distributed outcome variable and possibly unequal study-level variances, where the object of inference is the difference in means between a treatment and control group. A common complication in such an analysis is missing sample variances for some studies. A frequently used approach is to impute the weighted (by sample size) mean of the observed variances (mean imputation). Another approach is to include only those studies with variances reported (complete case analysis). Both mean imputation and complete case analysis are only valid under the missing-completely-at-random assumption, and even then the inverse variance weights produced are not necessarily optimal. We propose a multiple imputation method employing gamma meta-regression to impute the missing sample variances. Our method takes advantage of study-level covariates that may be used to provide information about the missing data. Through simulation studies, we show that multiple imputation, when the imputation model is correctly specified, is superior to competing methods in terms of confidence interval coverage probability and type I error probability when testing a specified group difference. Finally, we describe a similar approach to handling missing variances in cross-over studies. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Importance of Thinking Locally for Mental Health: Data from Cross-Sectional Surveys Representing South East London and England

PubMed Central

Hatch, Stephani L.; Woodhead, Charlotte; Frissa, Souci; Fear, Nicola T.; Verdecchia, Maria; Stewart, Robert; Reichenberg, Abraham; Morgan, Craig; Bebbington, Paul; McManus, Sally; Brugha, Traolach; Kankulu, Bwalya; Clark, Jennifer L.; Gazard, Billy; Medcalf, Robert; Hotopf, Matthew

2012-01-01

Background Reliance on national figures may be underestimating the extent of mental ill health in urban communities. This study demonstrates the necessity for local information on common mental disorder (CMD) and substance use by comparing data from the South East London Community Health (SELCoH) study with those from a national study, the 2007 English Adult Psychiatric Morbidity Study (APMS). Methodology/Principal Findings Data were used from two cross-sectional surveys, 1698 men and women residing in south London and 7403 men and women in England. The main outcome, CMD, was indicated by a score of 12 or above on the Revised Clinical Interview Schedule. Secondary outcomes included hazardous alcohol use and illicit drug use. SELCoH sample prevalence estimates of CMD were nearly twice that of the APMS England sample estimates. There was a four-fold greater proportion of depressive episode in the SELCoH sample than the APMS sample. The prevalence of hazardous alcohol use was higher in the national sample. Illicit drug use in the past year was higher in the SELCoH sample, with cannabis and cocaine the illicit drugs reported most frequently in both samples. In comparisons of the SELCoH sample with the APMS England sample and the APMS sample from the Greater London area in combined datasets, these differences remained after adjusting for socio-demographic and socioeconomic indicators for all outcomes. Conclusions/Significance Local information for estimating the prevalence of CMD and substance use is essential for surveillance and service planning. There were similarities in the demographic and socioeconomic factors related to CMD and substance use across samples. PMID:23251330

Measuring the gut microbiome in birds: Comparison of faecal and cloacal sampling.

PubMed

Videvall, Elin; Strandh, Maria; Engelbrecht, Anel; Cloete, Schalk; Cornwallis, Charlie K

2018-05-01

The gut microbiomes of birds and other animals are increasingly being studied in ecological and evolutionary contexts. Numerous studies on birds and reptiles have made inferences about gut microbiota using cloacal sampling; however, it is not known whether the bacterial community of the cloaca provides an accurate representation of the gut microbiome. We examined the accuracy with which cloacal swabs and faecal samples measure the microbiota in three different parts of the gastrointestinal tract (ileum, caecum, and colon) using a case study on juvenile ostriches, Struthio camelus, and high-throughput 16S rRNA sequencing. We found that faeces were significantly better than cloacal swabs in representing the bacterial community of the colon. Cloacal samples had a higher abundance of Gammaproteobacteria and fewer Clostridia relative to the gut and faecal samples. However, both faecal and cloacal samples were poor representatives of the microbial communities in the caecum and ileum. Furthermore, the accuracy of each sampling method in measuring the abundance of different bacterial taxa was highly variable: Bacteroidetes was the most highly correlated phylum between all three gut sections and both methods, whereas Actinobacteria, for example, was only strongly correlated between faecal and colon samples. Based on our results, we recommend sampling faeces, whenever possible, as this sample type provides the most accurate assessment of the colon microbiome. The fact that neither sampling technique accurately portrayed the bacterial community of the ileum nor the caecum illustrates the difficulty in noninvasively monitoring gut bacteria located further up in the gastrointestinal tract. These results have important implications for the interpretation of avian gut microbiome studies. © 2017 John Wiley & Sons Ltd.

Reaching women who do not participate in the regular cervical cancer screening programme by offering self-sampling kits: a systematic review and meta-analysis of randomised trials.

PubMed

Verdoodt, F; Jentschke, M; Hillemanns, P; Racey, C S; Snijders, P J F; Arbyn, M

2015-11-01

Population coverage for cervical cancer screening is an important determinant explaining differences in the incidence of cervical cancer between countries. Offering devices for self-sampling has the potential to increase participation of hard-to-reach women. A systematic review and meta-analysis were performed to evaluate the participation after an invitation including a self-sampling device (self-sampling arm) versus an invitation to have a sample taken by a health professional (control arm), sent to under-screened women. Sixteen randomised studies were found eligible. In an intention-to-treat analysis, the pooled participation in the self-sampling arm was 23.6% (95% confidence interval (CI)=20.2-27.3%), when self-sampling kits were sent by mail to all women, versus 10.3% (95% CI=6.2-15.2%) in the control arm (participation difference: 12.6% [95% CI=9.3-15.9]). When women had to opt-in to receive the self-sampling device, as used in three studies, the pooled participation was not higher in the self-sampling compared to the control arm (participation difference: 0.2% [95% CI=-4.5-4.9%]). An increased participation was observed in the self-sampling arm compared to the control arm, if self-sampling kits were sent directly to women at their home address. However, the size of the effect varied substantially among studies. Since participation was similar in both arms when women had to opt-in, future studies are warranted to discern opt-in scenarios that are most acceptable to women. Copyright © 2015 Elsevier Ltd. All rights reserved.

The association between intelligence and lifespan is mostly genetic.

PubMed

Arden, Rosalind; Luciano, Michelle; Deary, Ian J; Reynolds, Chandra A; Pedersen, Nancy L; Plassman, Brenda L; McGue, Matt; Christensen, Kaare; Visscher, Peter M

2016-02-01

Several studies in the new field of cognitive epidemiology have shown that higher intelligence predicts longer lifespan. This positive correlation might arise from socioeconomic status influencing both intelligence and health; intelligence leading to better health behaviours; and/or some shared genetic factors influencing both intelligence and health. Distinguishing among these hypotheses is crucial for medicine and public health, but can only be accomplished by studying a genetically informative sample. We analysed data from three genetically informative samples containing information on intelligence and mortality: Sample 1, 377 pairs of male veterans from the NAS-NRC US World War II Twin Registry; Sample 2, 246 pairs of twins from the Swedish Twin Registry; and Sample 3, 784 pairs of twins from the Danish Twin Registry. The age at which intelligence was measured differed between the samples. We used three methods of genetic analysis to examine the relationship between intelligence and lifespan: we calculated the proportion of the more intelligent twins who outlived their co-twin; we regressed within-twin-pair lifespan differences on within-twin-pair intelligence differences; and we used the resulting regression coefficients to model the additive genetic covariance. We conducted a meta-analysis of the regression coefficients across the three samples. The combined (and all three individual samples) showed a small positive phenotypic correlation between intelligence and lifespan. In the combined sample observed r = .12 (95% confidence interval .06 to .18). The additive genetic covariance model supported a genetic relationship between intelligence and lifespan. In the combined sample the genetic contribution to the covariance was 95%; in the US study, 84%; in the Swedish study, 86%, and in the Danish study, 85%. The finding of common genetic effects between lifespan and intelligence has important implications for public health, and for those interested in the genetics of intelligence, lifespan or inequalities in health outcomes including lifespan. © The Author 2015; Published by Oxford University Press on behalf of the International Epidemiological Association.

The UK Biobank sample handling and storage validation studies.

PubMed

Peakman, Tim C; Elliott, Paul

2008-04-01

and aims UK Biobank is a large prospective study in the United Kingdom to investigate the role of genetic factors, environmental exposures and lifestyle in the causes of major diseases of late and middle age. It involves the collection of blood and urine from 500 000 individuals aged between 40 and 69 years. How the samples are collected, processed and stored will have a major impact on the future scientific usefulness of the UK Biobank resource. A series of validation studies was recommended to test the robustness of the draft sample handling and storage protocol. Samples of blood and urine were collected from 40 healthy volunteers and either processed immediately according to the protocol or maintained at specified temperatures (4 degrees C for all tubes with the exception of vacutainers containing acid citrate dextrose that were maintained at 18 degrees C) for 12, 24 or 36 h prior to processing. A further sample was maintained for 24 h at 4 degrees C, processed and the aliquots frozen at -80 degrees C for 20 days and then thawed under controlled conditions. The stability of the samples was compared for the different times in a wide variety of assays. The samples maintained at 4 degrees C were stable for at least 24 h after collection for a wide range of assays. Small but significant changes were observed in metabonomic studies in samples maintained at 4 degrees C for 36 h. There was no degradation of the samples for a range of biochemical assays after short-term freezing and thawing under controlled conditions. Whole blood maintained at 18 degrees C for 24 h in vacutainers containing acid citrate dextrose is suitable for viral immortalization techniques. The validation studies reported in this supplement provide justification for the sample handling and storage procedures adopted in the UK Biobank project.

The association between intelligence and lifespan is mostly genetic

PubMed Central

Arden, Rosalind; Deary, Ian J; Reynolds, Chandra A; Pedersen, Nancy L; Plassman, Brenda L; McGue, Matt; Christensen, Kaare; Visscher, Peter M

2016-01-01

Abstract Background: Several studies in the new field of cognitive epidemiology have shown that higher intelligence predicts longer lifespan. This positive correlation might arise from socioeconomic status influencing both intelligence and health; intelligence leading to better health behaviours; and/or some shared genetic factors influencing both intelligence and health. Distinguishing among these hypotheses is crucial for medicine and public health, but can only be accomplished by studying a genetically informative sample. Methods: We analysed data from three genetically informative samples containing information on intelligence and mortality: Sample 1, 377 pairs of male veterans from the NAS-NRC US World War II Twin Registry; Sample 2, 246 pairs of twins from the Swedish Twin Registry; and Sample 3, 784 pairs of twins from the Danish Twin Registry. The age at which intelligence was measured differed between the samples. We used three methods of genetic analysis to examine the relationship between intelligence and lifespan: we calculated the proportion of the more intelligent twins who outlived their co-twin; we regressed within-twin-pair lifespan differences on within-twin-pair intelligence differences; and we used the resulting regression coefficients to model the additive genetic covariance. We conducted a meta-analysis of the regression coefficients across the three samples. Results: The combined (and all three individual samples) showed a small positive phenotypic correlation between intelligence and lifespan. In the combined sample observed r  = .12 (95% confidence interval .06 to .18). The additive genetic covariance model supported a genetic relationship between intelligence and lifespan. In the combined sample the genetic contribution to the covariance was 95%; in the US study, 84%; in the Swedish study, 86%, and in the Danish study, 85%. Conclusions: The finding of common genetic effects between lifespan and intelligence has important implications for public health, and for those interested in the genetics of intelligence, lifespan or inequalities in health outcomes including lifespan. PMID:26213105

Evaluation of commercial kit based on loop-mediated isothermal amplification for rapid detection of low levels of uninjured and injured Salmonella on duck meat, bean sprouts, and fishballs in Singapore.

PubMed

Lim, Hazel Sin Yue; Zheng, Qianwang; Miks-Krajnik, Marta; Turner, Matthew; Yuk, Hyun-Gyun

2015-06-01

The objective of this study was to evaluate performance of the commercial kit based on loop-mediated isothermal amplification (LAMP) in comparison with the International Organization for Standardization method for detecting uninjured and sublethally injured Salmonella cells artificially inoculated at levels of 10(0) and 10(1) CFU/25 g on raw duck wing, raw mung bean sprouts, and processed fishballs. Injured cells were prepared by a heat treatment for duck wings and fishball samples and a chlorine treatment for bean sprout samples. Additionally, a validation study was performed on naturally contaminated food samples sold in Singapore. A total of 110 samples of each commodity were analyzed in this study. Regardless of inoculum levels, the detection by the commercial LAMP kit showed 100% sensitivity and specificity for both inoculated and uninoculated samples compared with the International Organization for Standardization method, with the exception of bean sprout samples. Only 20% of bean sprout samples inoculated with 10(0) CFU/25 g injured Salmonella cells were positive by using the commercial LAMP-based kit. However, all negative samples became positive following a secondary enrichment in Rappaport-Vassiliadis medium with soy broth or after concentration by centrifugation. These results suggest that secondary enrichment or centrifugation should be considered as an additional step to increase the sensitivity of the commercial LAMP-based kit with low numbers of injured target cells in samples with high background microflora (such as mung bean sprouts). The validation study also showed that the commercial LAMP-based kit provided 91% sensitivity and 95% specificity for naturally contaminated samples. Thus, this study demonstrates that the commercial LAMP-based kit might be a cost-effective method, as this system could provide rapid, accurate detection of both uninjured and injured Salmonella cells on raw duck wings, raw mung bean sprouts, and processed fishballs in less than 26 h.

A post-mortem survey on end-of-life decisions using a representative sample of death certificates in Flanders, Belgium: research protocol

PubMed Central

Chambaere, Kenneth; Bilsen, Johan; Cohen, Joachim; Pousset, Geert; Onwuteaka-Philipsen, Bregje; Mortier, Freddy; Deliens, Luc

2008-01-01

Background Reliable studies of the incidence and characteristics of medical end-of-life decisions with a certain or possible life shortening effect (ELDs) are indispensable for an evidence-based medical and societal debate on this issue. This article presents the protocol drafted for the 2007 ELD Study in Flanders, Belgium, and outlines how the main aims and challenges of the study (i.e. making reliable incidence estimates of end-of-life decisions, even rare ones, and describing their characteristics; allowing comparability with past ELD studies; guaranteeing strict anonymity given the sensitive nature of the research topic; and attaining a sufficient response rate) are addressed in a post-mortem survey using a representative sample of death certificates. Study design Reliable incidence estimates are achievable by using large at random samples of death certificates of deceased persons in Flanders (aged one year or older). This entails the cooperation of the appropriate administrative authorities. To further ensure the reliability of the estimates and descriptions, especially of less prevalent end-of-life decisions (e.g. euthanasia), a stratified sample is drawn. A questionnaire is sent out to the certifying physician of each death sampled. The questionnaire, tested thoroughly and avoiding emotionally charged terms is based largely on questions that have been validated in previous national and European ELD studies. Anonymity of both patient and physician is guaranteed through a rigorous procedure, involving a lawyer as intermediary between responding physicians and researchers. To increase response we follow the Total Design Method (TDM) with a maximum of three follow-up mailings. Also, a non-response survey is conducted to gain insight into the reasons for lack of response. Discussion The protocol of the 2007 ELD Study in Flanders, Belgium, is appropriate for achieving the objectives of the study; as past studies in Belgium, the Netherlands, and other European countries have shown, strictly anonymous and thorough surveys among physicians using a large, stratified, and representative death certificate sample are most suitable in nationwide studies of incidence and characteristics of end-of-life decisions. There are however also some limitations to the study design. PMID:18752659

The Importance of Meteorite Collections to Sample Return Missions: Past, Present, and Future Considerations

NASA Technical Reports Server (NTRS)

Welzenbach, L. C.; McCoy, T. J.; Glavin, D. P.; Dworkin, J. P.; Abell, P. A.

2012-01-01

While much of the scientific community s current attention is drawn to sample return missions, it is the existing meteorite and cosmic dust collections that both provide the paradigms to be tested by these missions and the context for interpreting the results. Recent sample returns from the Stardust and Hayabusa missions provided us with new materials and insights about our Solar System history and processes. As an example, Stardust sampled CAIs among the population of cometary grains, requiring extensive and unexpected radial mixing in the early solar nebula. This finding would not have been possible, however, without extensive studies of meteoritic CAIs that established their high-temperature, inner Solar System formation. Samples returned by Stardust also revealed the first evidence of a cometary amino acid, a discovery that would not have been possible with current in situ flight instrument technology. The Hayabusa mission provided the final evidence linking ordinary chondrites and S asteroids, a hypothesis that developed from centuries of collection and laboratory and ground-based telescopic studies. In addition to these scientific findings, studies of existing meteorite collections have defined and refined the analytical techniques essential to studying returned samples. As an example, the fortuitous fall of the Allende CV3 and Murchison CM2 chondrites within months before the return of Apollo samples allowed testing of new state-of-the-art analytical facilities. The results of those studies not only prepared us to better study lunar materials, but unanticipated discoveries changed many of our concepts about the earliest history and processes of the solar nebula. This synergy between existing collections and future space exploration is certainly not limited to sample return missions. Laboratory studies confirmed the existence of meteorites from Mars and raised the provocative possibility of preservation of ancient microbial life. The laboratory studies in turn led to a new wave of Mars exploration that ultimately could lead to sample return focused on evidence for past or present life. This partnership between collections and missions will be increasingly important in the coming decades as we discover new questions to be addressed and identify targets for for both robotic and human exploration . Nowhere is this more true than in the ultimate search for the abiotic and biotic processes that produced life. Existing collections also provide the essential materials for developing and testing new analytical schemes to detect the rare markers of life and distinguish them from abiotic processes. Large collections of meteorites and the new types being identified within these collections, which come to us at a fraction of the cost of a sample return mission, will continue to shape the objectives of future missions and provide new ways of interpreting returned samples.

X-ray diffraction on radioactive materials

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

Schiferl, D.; Roof, R.B.

1978-01-01

X-ray diffraction studies on radioactive materials are discussed with the aim of providing a guide to new researchers in the field. Considerable emphasis is placed on the safe handling and loading of not-too-exotic samples. Special considerations such as the problems of film blackening by the gamma rays and changes induced by the self-irradiation of the sample are covered. Some modifications of common diffraction techniques are presented. Finally, diffraction studies on radioactive samples under extreme conditions are discussed, with primary emphasis on high-pressure studies involving diamond-anvil cells.

The methodology study of time accelerated irradiation of elastomers

NASA Astrophysics Data System (ADS)

Ito, Masayuki

2005-07-01

The article studied the methods how to shorten the irradiation time by increasing dose rate without changing the relationship between dose versus properties of degraded samples. The samples used were nine kinds of EPDM which have different compounding formula. The different dose of Co-γ ray was exposed to the samples. The maximum dose was 2 MGy. The reference condition to be compared with two short time test conditions is irradiation of 0.33 kGy/h at room temperature. Two methods shown below were studied as the time-accelerate irradiation conditions.

Definition of intercultural competence (IC) in undergraduate students at a private university in the USA: A mixed-methods study

PubMed Central

Gierke, Lioba; Binder, Nadine; Heckmann, Mark; Odağ, Özen; Leiser, Anne

2018-01-01

Introduction Intercultural competence (IC) is an important skill to be gained from higher education. However, it remains unclear what IC means to students and what factors might influence their definitions of IC. The aim of the current study was to qualitatively assess how students at one higher education institution in the USA define IC and to quantitatively test for relationships among IC components and various demographic characteristics, including intercultural experience and study context. A further aim was to descriptively compare the IC definitions from the US sample with the definitions obtained from another sample of university students in Germany. Materials and methods A purposive sample of n = 93 undergraduate, second semester students at Dickinson College, USA, participated in the study by completing an online questionnaire. The qualitative data were content-analyzed to define the dimensions of IC. The quantitative data were cluster-analyzed to assess the multivariate relationships among the IC components and the demographic characteristics of the sample. Results The most important dimensions of IC were Knowledge, External Outcomes (interaction, communication), and Attitudes (respect, tolerance) according to the US sample. The most frequently chosen dimensions of IC differed between both samples: Knowledge was chosen by the sample in the USA while External Outcomes was chosen by the sample in Germany. Relative to the US sample, significantly more students chose Attitudes, External Outcomes, and Intrapersonal Skills in the sample in Germany. The relationships among IC components and demographic characteristics were only weak in the US sample. A person with IC was rated as Open-minded and Respectful by students who lived predominantly in the USA or Tolerant and Curious by those who lived outside the USA for at least six months. Discussion The current results suggest that students residing in two countries (USA or Germany) define IC using similar dimensions. However, IC definitions may depend on the intercultural experience and the current global discourse. Longitudinal studies with representative samples are required to assess how IC definitions change over time. PMID:29698525

Short communication: Comparison of pH, volatile fatty acids, and microbiome of rumen samples from preweaned calves obtained via cannula or stomach tube.

PubMed

Terré, M; Castells, L; Fàbregas, F; Bach, A

2013-08-01

The objective of this study was to compare rumen samples from young dairy calves obtained via a stomach tube (ST) or a ruminal cannula (RC). Five male Holstein calves (46±4.0 kg of body weight and 11±4.9 d of age) were ruminally cannulated at 15 d of age. Calves received 4 L/d of a commercial milk replacer (25% crude protein and 19.2% fat) at 12.5% dry matter, and were provided concentrate and chopped oats hay ad libitum throughout the study (56 d). In total, 29 paired rumen samples were obtained weekly throughout the study in most of the calves by each extraction method. These samples were used to determine pH and volatile fatty acids (VFA) concentration, and to quantify Prevotella ruminicola and Streptococcus bovis by quantitative PCR. Furthermore, a denaturing gradient gel electrophoresis was performed on rumen samples harvested during wk 8 of the study to determine the degree of similarity between rumen bacteria communities. Rumen pH was 0.30 units greater in ST compared with RC samples. Furthermore, total VFA concentrations were greater in RC than in ST samples. However, when analyzing the proportion of each VFA by ANOVA, no differences were found between the sampling methods. The quantification of S. bovis and P. ruminicola was similar in both extraction methods, and values obtained using different methods were highly correlated (R(2)=0.89 and 0.98 for S. bovis and P. ruminicola, respectively). Fingerprinting analysis showed similar bacteria band profiles between samples obtained from the same calves using different extraction methods. In conclusion, when comparing rumen parameters obtained using different sampling techniques, it is recommended that VFA profiles be used rather than total VFA concentrations, as total VFA concentrations are more affected by the method of collection. Furthermore, although comparisons of pH across studies should be avoided when samples are not obtained using the same sampling method, the comparison of fingerprinting of a bacteria community or a specific rumen bacterium is valid. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Sample size requirements for the design of reliability studies: precision consideration.

PubMed

Shieh, Gwowen

2014-09-01

In multilevel modeling, the intraclass correlation coefficient based on the one-way random-effects model is routinely employed to measure the reliability or degree of resemblance among group members. To facilitate the advocated practice of reporting confidence intervals in future reliability studies, this article presents exact sample size procedures for precise interval estimation of the intraclass correlation coefficient under various allocation and cost structures. Although the suggested approaches do not admit explicit sample size formulas and require special algorithms for carrying out iterative computations, they are more accurate than the closed-form formulas constructed from large-sample approximations with respect to the expected width and assurance probability criteria. This investigation notes the deficiency of existing methods and expands the sample size methodology for the design of reliability studies that have not previously been discussed in the literature.

On the abiotic formation of amino acids. I - HCN as a precursor of amino acids detected in extracts of lunar samples. II - Formation of HCN and amino acids from simulated mixtures of gases released from lunar samples

NASA Technical Reports Server (NTRS)

Yuasa, S.; Flory, D.; Basile, B.; Oro, J.

1984-01-01

Two studies on the abiotic formation of amino acids are presented. The first study demonstrates the role of hydrogen cyanide as a precursor of amino acids detected in extracts of lunar samples. The formation of several amino acids, including glycine, alanine, aspartic acid, and glutamic acid, under conditions similar to those used for the analysis of lunar samples is demonstrated. The second study investigates the formation of hydrogen cyanide as well as amino acids from lunar-sample gas mixtures under electrical discharge conditions. These results extend the possibility of synthesis of amino acids to planetary bodies with primordial atmospheres less reducing than a mixture of methane, ammonia, hydrogen and water.

Outcome-Dependent Sampling Design and Inference for Cox’s Proportional Hazards Model

PubMed Central

Yu, Jichang; Liu, Yanyan; Cai, Jianwen; Sandler, Dale P.; Zhou, Haibo

2016-01-01

We propose a cost-effective outcome-dependent sampling design for the failure time data and develop an efficient inference procedure for data collected with this design. To account for the biased sampling scheme, we derive estimators from a weighted partial likelihood estimating equation. The proposed estimators for regression parameters are shown to be consistent and asymptotically normally distributed. A criteria that can be used to optimally implement the ODS design in practice is proposed and studied. The small sample performance of the proposed method is evaluated by simulation studies. The proposed design and inference procedure is shown to be statistically more powerful than existing alternative designs with the same sample sizes. We illustrate the proposed method with an existing real data from the Cancer Incidence and Mortality of Uranium Miners Study. PMID:28090134

Water-quality assessment of the Ozark Plateaus study unit, Arkansas, Kansas, Missouri, and Oklahoma- summary of information on pesticides, 1970-90

USGS Publications Warehouse

Bell, Richard W.; Joseph, Robert L.; Freiwald, David A.

1996-01-01

Historical pesticide data from 1970-90 were compiled for 140 surface-water, 92 ground-water, 55 streambed-sediment, and 120 biological-tissue sampling sites within the Ozark Plateaus National Water-Quality Assessment Program study unit. Surface-water, bed-sediment, and biological-tissue sites have drainage basins predominantly in the Springfield and Salem Plateaus; ground-water sites are predominantly located in the Osage Plains and Mississippi Alluvial Plain. Many sites were sampled only once or twice during this period. A large percentage of the samples were collected in the mid-1970's and early 1980's for surface water, 1990 for ground water, the late 1980's for surface water, 1990 for ground water, the late 1980's for bed sediment, and the early 1980's for biological tissue. Pesticide use was approximately 4.2 million pounds per year of active ingredients from 1982-85 in the study unit and was generally greatest in the Springfield and Salem Plateaus pasturelands and in the Osage Plains and Mississippi Alluvial Plain cropland areas. The most frequently applied pesticide in the study unit was 2,4-D. Alachlor was the second most applied pesticide. Corn, pasture, rice, sorghum, and soybeans received approximately 90 percent of the pesticides applied within the study unit. The highest pesticide application rate per acre occurred on these crops in the Osage Plains and Mississippi Alluvial Plain. Pastureland was the predominant crop type in 50 of the 94 counties in the study unit. Toxaphene, the pesticide having the most number of detections in surface water, was found in 17 of 866 samples from 5 of 112 sites. Concentrations ranged from 0.1 to 6.0 micrograms per liter. Six other pesticides or pesticide metabolites were detected in 12 or more surface-water samples: DDE, dieldrin, DDT, aldrin, 2,4-D, and lindane. The maximum concentration for these pesticides was less than 1.0 micrograms per liter. Atrazine, the pesticide having the most number of detections in ground water, was found in 15 of 95 samples from 15 of 79 wells with concentrations ranging from 0.1 to 8.2 micrograms per liter. Metolachlor, alachlor, and prometon were detected more than once with maximum concentrations less than 1.0 micrograms per liter, except for prometon (2.4 micrograms per liter). Chlordane was the pesticide having the most number of detections in bed sediment and biological tissue. Chlordane was detected in 12 of 73 samples from 10 of 45 bed-sediment sites with concentrations ranging from 2.0 to 240 micrograms per kilogram. In biological tissue, chlordane was found in 93 of 151 samples from 39 of 53 sites with concentrations ranging from 0.009 to 8.6 milligrams per kilogram. Other pesticides or pesticide metabolites detected more than once in bed sediment include DDT, DDD, p,p'-DDE, DDE, and hexachlorobenzene and in biological tissue include DDT, p,p'-DDE, and hexachlorobenzene. Quality criteria or standards have been established for 15 of the pesticides detected in the study unit. For surface-water samples, the drinking water maximum contaminant level for alachlor was exceeded in one sample from one site in 1982. For ground-water samples, the drinking water maximum contaminant level for atrazine was exceeded in four samples from four wells in 1990. For biological-tissue samples collected during the years 1982-89, the fish tissue action levels for chlordane (19 sites; 26 samples), heptachlor epoxide (3 sites; 3 samples), p,p'-DDE (2 sites; 2 samples), dieldrin (2 sites, 2 samples), and mirex (1 site; 1 sample) were exceeded. For bed-sediment samples, quality criteria or standards were not exceeded for any pesticide. Pesticides do not pose any widespread or persistent problems in the study unit, based on the limited number of samples that exceeded quality criteria and standards.

Recruitment of healthy first-trimester pregnant women: lessons from the Chemicals, Health & Pregnancy study (CHirP).

PubMed

Webster, Glenys M; Teschke, Kay; Janssen, Patricia A

2012-02-01

To describe and evaluate recruitment techniques used to enroll 152 healthy pregnant women fewer than 15 weeks gestation into a prospective study of environmental chemical exposure during pregnancy. Posters, a website, online and print advertising, recruitment emails, media coverage, recruitment from clinic waiting rooms, networking within the pregnancy community and presenting a study booth at baby "trade shows" were used to advertise the study. Participants had to meet a strict set of eligibility criteria, and were asked to donate two-second-trimester blood samples, complete two questionnaires, have samples of air, dust, lint and tap water collected from their homes, and donate a cord blood sample at delivery. Over 17 months, 171 women enrolled (49% of initial contacts, and 99% of all eligible women) and 152 women completed the study (89% retention). Total recruitment costs were approximately $400 Cdn per final participant. Posters, study booth presentations and online advertising generated the most inquiries about the study. Word of mouth, referral from another study and direct email were the most cost-effective strategies. Not surprisingly, the recruited study population was less ethnically diverse, more affluent and more educated than the background population of pregnant women in Vancouver. A combination of passive and active recruitment techniques were successful for recruiting healthy women in roughly the first trimester of pregnancy (<15 weeks gestation). While a convenience sample of women is suitable for our study questions, additional strategies may be required to recruit a more representative pregnant population in future studies.

An empirical comparison of isolate-based and sample-based definitions of antimicrobial resistance and their effect on estimates of prevalence.

PubMed

Humphry, R W; Evans, J; Webster, C; Tongue, S C; Innocent, G T; Gunn, G J

2018-02-01

Antimicrobial resistance is primarily a problem in human medicine but there are unquantified links of transmission in both directions between animal and human populations. Quantitative assessment of the costs and benefits of reduced antimicrobial usage in livestock requires robust quantification of transmission of resistance between animals, the environment and the human population. This in turn requires appropriate measurement of resistance. To tackle this we selected two different methods for determining whether a sample is resistant - one based on screening a sample, the other on testing individual isolates. Our overall objective was to explore the differences arising from choice of measurement. A literature search demonstrated the widespread use of testing of individual isolates. The first aim of this study was to compare, quantitatively, sample level and isolate level screening. Cattle or sheep faecal samples (n=41) submitted for routine parasitology were tested for antimicrobial resistance in two ways: (1) "streak" direct culture onto plates containing the antimicrobial of interest; (2) determination of minimum inhibitory concentration (MIC) of 8-10 isolates per sample compared to published MIC thresholds. Two antibiotics (ampicillin and nalidixic acid) were tested. With ampicillin, direct culture resulted in more than double the number of resistant samples than the MIC method based on eight individual isolates. The second aim of this study was to demonstrate the utility of the observed relationship between these two measures of antimicrobial resistance to re-estimate the prevalence of antimicrobial resistance from a previous study, in which we had used "streak" cultures. Boot-strap methods were used to estimate the proportion of samples that would have tested resistant in the historic study, had we used the isolate-based MIC method instead. Our boot-strap results indicate that our estimates of prevalence of antimicrobial resistance would have been considerably lower in the historic study had the MIC method been used. Finally we conclude that there is no single way of defining a sample as resistant to an antimicrobial agent. The method used greatly affects the estimated prevalence of antimicrobial resistance in a sampled population of animals, thus potentially resulting in misleading results. Comparing methods on the same samples allows us to re-estimate the prevalence from other studies, had other methods for determining resistance been used. The results of this study highlight the importance of establishing what the most appropriate measure of antimicrobial resistance is, for the proposed purpose of the results. Copyright © 2017 Elsevier B.V. All rights reserved.

Cognitive Behavioral Therapy: A Meta-Analysis of Race and Substance Use Outcomes

PubMed Central

Windsor, Liliane Cambraia; Jemal, Alexis; Alessi, Edward

2015-01-01

Cognitive behavioral therapy (CBT) is an effective intervention for reducing substance use. However, because CBT trials have included predominantly White samples caution must be used when generalizing these effects to Blacks and Hispanics. This meta-analysis compared the impact of CBT in reducing substance use between studies with a predominantly non-Hispanic White sample (hereafter NHW studies) and studies with a predominantly Black and/or Hispanic sample (hereafter BH studies). From 322 manuscripts identified in the literature, 17 met criteria for inclusion. Effect sizes between CBT and comparison group at posttest had similar effects on substance abuse across NHW and BH studies. However, when comparing pre-posttest effect sizes from groups receiving CBT between NHW and BH studies, CBT’s impact was significantly stronger in NHW studies. T-test comparisons indicated reduced retention/engagement in BH studies, albeit failing to reach statistical significance. Results highlight the need for further research testing CBT’s impact on substance use among Blacks and Hispanics. PMID:25285527

Retirement Planning and Counseling: Issues and Challenges for Teachers in Public Schools in the Sekondi Circuit

ERIC Educational Resources Information Center

Wilson, Kwesi Nkum; Aggrey, Ellen Aba Munkua

2012-01-01

The purpose of the study was to explore retirement planning, challenges, and counseling among teachers of public schools in the Sekondi Circuit in the Western Region, Ghana. A sample of 50 teachers was selected through convenience sampling. Only teachers who expressed interest in participating in the study were sampled. The main instrument for…

Practical Guidelines for Evaluating Sampling Designs in Survey Studies.

ERIC Educational Resources Information Center

Fan, Xitao; Wang, Lin

The popularity of sample surveys in evaluation and research makes it necessary for consumers to tell a good survey from a poor one. Several sources were identified that gave advice on how to evaluate a sample design used in a survey study. The sources are either too limited or too extensive to be useful practically. The purpose of this paper is to…

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR FIELD COLLECTION OF YARD COMPOSITE SOIL SAMPLES (UA-F-5.1)

EPA Science Inventory

The purpose of this SOP is to establish a uniform procedure for the collection of yard composite soil samples in the field. This procedure was followed to ensure consistent and reliable collection of outdoor soil samples during the Arizona NHEXAS project and the Border study. Ke...

Partnership for a Drug-Free America: Partnership Attitude Tracking Study. Teens: Ethnic and Racial Trends, Spring 2002.

ERIC Educational Resources Information Center

Delaney, Barbara

The annual Partnership Attitude Tracking Study (PATS) tracks consumers' attitudes about illegal drugs. PATS consists of two nationally projectable samples: a teen sample for students in grades 7-12 and a parent sample. The 2002 PATS, conducted in homes and schools, collected data using self-report surveys. Results indicate that after a decade of…

The Influence of Support for Innovation on Organizational Innovation: Taking Organizational Learning as a Mediator

ERIC Educational Resources Information Center

Hsiao, Hsi-Chi; Chang, Jen-Chia; Chen, Su-Chang

2014-01-01

The purpose of this study was to examine the role of organizational learning as a mediator variable between support for innovation and organizational innovation. Samples for this study were randomly selected from 22 technological colleges in Taiwan. The final sample included 322 participants in the full sample which accounted for 58.42 % of the…

Comparative Financial Statistics for Public Two-Year Colleges: FY 1994 Peer Groups Sample.

ERIC Educational Resources Information Center

Dickmeyer, Nathan; Meeker, Bradley

Comparative financial information derived from a national sample of 427 two-year colleges is presented in this report for fiscal year 1993-94, including data for the national sample and 6 groups of peer institutions. The first section provides introductory information on the annual study, reviewing the objectives of the study and potential uses of…

Sample Invariance of the Structural Equation Model and the Item Response Model: A Case Study.

ERIC Educational Resources Information Center

Breithaupt, Krista; Zumbo, Bruno D.

2002-01-01

Evaluated the sample invariance of item discrimination statistics in a case study using real data, responses of 10 random samples of 500 people to a depression scale. Results lend some support to the hypothesized superiority of a two-parameter item response model over the common form of structural equation modeling, at least when responses are…

The Preparation of Gelatine-Embedded Soil and Litter Sections and Their Application to Some Soil Ecological Studies.

ERIC Educational Resources Information Center

Anderson, J. M.

1978-01-01

A method is described for preparing large gelatine-embedded soil sections for ecological studies. Sampling methods reduce structural disturbance of the samples to a minimum and include freezing the samples in the field to kill soil invertebrates in their natural microhabitats. Projects are suggested for upper secondary school students. (Author/BB)

The ethics of research on stored biological samples: outcomes of a Workshop.

PubMed

Vaz, Manjulika; Sridhar, T S; Pai, Sanjay A

2016-01-01

Research is often conducted using laboratory samples and data. The ethical issues that arise in a study involving residual samples are considerably different from those arising in a prospective study. Some of these ethical issues concern the risks to confidentiality, individual autonomy, trust in and credibility of the researcher or the research, commercialisation and even the nomenclature involved.

Psychometric Properties of the Resiliency Scales for Children and Adolescents and Use for Youth with Psychiatric Disorders

ERIC Educational Resources Information Center

Prince-Embury, Sandra

2010-01-01

This study examines psychometric properties of the Resiliency Scales for Children and Adolescents (RSCA) in two clinical samples: one child sample (n = 110) and one adolescent sample (n = 178). The purpose of the study was to examine the distribution characteristics and internal consistency of RSCA scale, subscale, and index scores for youth who…

Studies on the Presence of Mycotoxins in Biological Samples: An Overview

PubMed Central

Escrivá, Laura; Font, Guillermina; Manyes, Lara

2017-01-01

Mycotoxins are fungal secondary metabolites with bioaccumulation levels leading to their carry-over into animal fluids, organs, and tissues. As a consequence, mycotoxin determination in biological samples from humans and animals has been reported worldwide. Since most mycotoxins show toxic effects at low concentrations and considering the extremely low levels present in biological samples, the application of reliable detection methods is required. This review summarizes the information regarding the studies involving mycotoxin determination in biological samples over the last 10 years. Relevant data on extraction methodology, detection techniques, sample size, limits of detection, and quantitation are presented herein. Briefly, liquid-liquid extraction followed by LC-MS/MS determination was the most common technique. The most analyzed mycotoxin was ochratoxin A, followed by zearalenone and deoxynivalenol—including their metabolites, enniatins, fumonisins, aflatoxins, T-2 and HT-2 toxins. Moreover, the studies were classified by their purpose, mainly focused on the development of analytical methodologies, mycotoxin biomonitoring, and exposure assessment. The study of tissue distribution, bioaccumulation, carry-over, persistence and transference of mycotoxins, as well as, toxicokinetics and ADME (absorption, distribution, metabolism and excretion) were other proposed goals for biological sample analysis. Finally, an overview of risk assessment was discussed. PMID:28820481

Human papilloma virus 18 detection in oral squamous cell carcinoma and potentially malignant lesions using saliva samples.

PubMed

Goot-Heah, Khor; Kwai-Lin, Thong; Froemming, Gabriele Ruth Anisah; Abraham, Mannil Thomas; Nik Mohd Rosdy, Nik Mohd Mazuan; Zain, Rosnah Binti

2012-01-01

Oral cancer has become one of the most prevalent cancers worldwide and human Papillomavirus is one of the risk factors for developing oral cancer. For this study HPV18 was chosen as it is one of the high risk HPV types and may lead to carcinogenesis. However, prevalence of HPV18 infection in Oral Squamous Cell Carcinoma in Malaysia remains unclear. This study aimed to investigate the viral load of HPV18 DNA in OSCC and potentially malignant lesions using saliva samples. Genomic DNAs of thirty saliva samples of normal subjects and thirty saliva samples compromised of 16 samples from potentially malignant lesions and 14 of OSCC patients were amplified for HPV18 DNA using a nested polymerase chain reaction analysis. All PCR products were then analyzed using the Bioanalyzer to confirm presence of HPV18 DNA. From thirty patients examined, only one of 30 (3.3%) cases was found to be positive for HPV18 in this study. The finding of this study revealed that there is a low viral detection of HPV18 in Malaysian OSCC by using saliva samples, suggesting that prevalence of HPV18 may not be important in this group of Malaysian OSCC.