Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “sampling design”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,171 records · Page 65Linked to original sources
PubMed2003

Foot and mouth disease and livestock husbandry practices in the Adamawa Province of Cameroon.

Foot and mouth disease (FMD) is a highly contagious viral disease of even-toed ungulates and is endemic in most of the tropics. A cross-sectional study using a stratified, two-stage random sample design was undertaken in the Adamawa Province of Cameroon. The objectives were to measure the reported herd-level prevalence of FMD and a range of husbandry practices important for its transmission. The owner-reported prevalence for the previous 12 months was 57.9% (50.4-65.4%), although there was a significant variation across the Province. During the previous dry season, 46.5% (38.6-54.4%) of herds had gone on transhumance. Herds had high numbers of contacts with other herds while on transhumance (98.6%), at pasture (95.8%) and at night (74.4%), with medians of 7-10, 4-6 and 1-3 daily contacts, respectively. The high level of endemic FMD and potential for disease spread presents a significant challenge for control and eradication. Locally sustainable methods need to be developed upon which larger regional control programmes could be built in the future.

Animal Husbandry↗
PubMed2004

Estimation of plant diversity at landscape level: a methodological approach applied to three Spanish rural areas.

Approaches linking biodiversity assessment with landscape structure are necessary in the framework of sustainable rural development. The present paper describes a methodology to estimate plant diversity involving landscape structure as a proportional weight associated with different plant communities found in the landscape mosaic. The area occupied by a plant community, its patch number or its spatial distribution of patches are variables that could be expressed in gamma plant diversity of a territory. The methodology applies (1) remote sensing information, to identify land cover and land use types; (2) aspect, to discriminate composition of plant communities in each land cover type; (3) multi-scale field techniques, to asses plant diversity; (4) affinity analysis of plant community composition, to validate the stratified random sampling design and (5) the additive model that partitions gamma diversity into its alpha and beta components. The method was applied to three Spanish rural areas and was able to record 150-260 species per ha. Species richness, Shannon information index and Simpson concentration index were used to measure diversity in each area. The estimation using Shannon diversity index and the product of patch number and patch interspersion as weighting of plant community diversity was found to be the most appropriate method of measuring plant diversity at the landscape level.

Biodiversity↗
PubMed2006

[How successful is inpatient treatment in child and adolescent psychiatry? Preliminary results of the Marburg Evaluation Project].

OBJECTIVES: From 1999 to 2006, the inpatient treatment of a complete clinical sample in a child and adolescent psychiatric hospital was evaluated in a naturalistic effectiveness study in order to obtain detailed information about the outcome of the therapies. METHODS: The project was realized as a longitudinal 1-sample design with measurements at three points in time (admission assessment; discharge assessment and 6-week follow-up; 1 1/2 year follow-up). An essential part of the assessments was conducted using standardized telephone interviews with the parents of the inpatients. The project included 1,321 inpatients; the 1 1/2 year follow-up was accomplished for 776 cases. RESULTS: In all repeated measurements, there were highly significant effects. The pre-post effect sizes were higher than 1. The effects which were achieved during inpatient treatment were stable over time with a slight improvement after treatment. The outcome of different diagnostic groups showed significant differences at the 1 1/2 year follow-up. CONCLUSIONS: The results should be used in the counselling of patients and their parents prior to starting therapy. It should be investigated whether the favourable results can be generalized for inpatient treatments in other hospitals of child psychiatry.

Adolescent↗
PubMed1997

Does unhappiness make you sick? The role of affect and neuroticism in the experience of common physical symptoms.

The relative strength of both affective state and the personality trait neuroticism in predicting common physical symptoms was tested. The authors used an event-sampling design to overcome methodological limitations of past research in the area. Contrary to much previous research, neuroticism was found to be unrelated to reports of physical symptoms, although it was found to be related to unpleasant affective state. Unpleasant affect bore a strong concurrent relation to the frequency of reported symptoms. Temporal relations between experiences of unpleasant affect and subsequent symptoms were found for some individuals, but wide individual variability was seen in both the strength and direction of this linkage. The findings suggest that when individuals are asked to report their subjective experiences of physical illness without the necessity to retrospect over significant periods of time, unpleasant affective state is more strongly related to experiences of symptoms than is the trait neuroticism.

Adaptation, Psychological↗
PubMed2001

Meta-analytic methods, the Rorschach, and the MMPI.

In response to concerns described by H. N. Garb, J. M. Wood, M. T. Nezworski, W. M. Grove, and W. J. Stejskal (2001), the authors present the weighted and unweighted means and medians of the effect sizes obtained by J. B. Hiller, R. Rosenthal, R. F. Bornstein, D. T. R. Berry, and S. Brunell-Neuleib (1999). These indices of central tendency are presented separately for Minnesota Multiphasic Personality Inventory (MMPI) and Rorschach effect sizes, both for all the studies in the meta-analysis and for a 10% trimmed sample designed to obtain more robust estimates of central tendency. The variability of these 4 indices is noticeably greater for the MMPI than for the Rorschach. Meta-analysts must compute, compare, and evaluate a variety of indices of central tendency, and they must examine the effects of moderator variables. The authors also comment briefly on the use of phi versus kappa, combining correlated effect sizes and possible hindsight biases.

Humans↗
PubMed2002

Neutralizing substitutes for leadership theory: leadership effects and common-source bias.

The purpose of this research was to examine alternative models of substitutes for leadership theory given the general lack of empirical support for the moderating effects postulated by the theory. On this basis, the research posited that the effects of substitutes also could be conceptualized as mediated relations. The research examined moderated and mediated relations for several sets of leader behaviors and substitutes that have been examined in the literature. The research design sampled 49 organizations, with 940 subordinates rating 156 leaders. Results, although generally not supportive of the moderator or mediator hypotheses, essentially demonstrated that leadership matters. The findings also suggest that prior significant effects in substitutes literature may be merely a statistical artifact, resulting from common-source bias.

Humans↗
PubMed2003

Interpersonal attraction and personality: what is attractive--self similarity, ideal similarity, complementarity or attachment security?

Little is known about whether personality characteristics influence initial attraction. Because adult attachment differences influence a broad range of relationship processes, the authors examined their role in 3 experimental attraction studies. The authors tested four major attraction hypotheses--self similarity, ideal-self similarity, complementarity, and attachment security--and examined both actual and perceptual factors. Replicated analyses across samples, designs, and manipulations showed that actual security and self similarity predicted attraction. With regard to perceptual factors, ideal similarity, self similarity, and security all were significant predictors. Whereas perceptual ideal and self similarity had incremental predictive power, perceptual security's effects were subsumed by perceptual ideal similarity. Perceptual self similarity fully mediated actual attachment similarity effects, whereas ideal similarity was only a partial mediator.

Adolescent↗
PubMed2007

Migrant mental health: a model for indicators of mental health and health care consumption.

OBJECTIVE: This study explores the relationship between mental health and health care consumption among migrants in the Netherlands. DESIGN: Samples of the Turkish (n = 648), Moroccan (n = 102), and Surinamese (n = 311) populations in Amsterdam were examined. The study tested a hypothesized model of risk factors for psychiatric morbidity, indicators of well-being, and indicators of health care consumption. The model was specified on the basis of information from earlier research on the sample and literature on the topic. The model was tested and refined using structural equation modeling. MAIN OUTCOME MEASURES: Psychiatric morbidity and well-being measures were assessed with the CIDI 1.1 and MOS-sf-36 subscales, respectively. Health care consumption was assessed by the question "Have you ever consulted one or more of these professionals or health care facilities with respect to mental health problems or problems related to alcohol or drugs usage?" RESULTS: The primary result of this study was the confirmation that health care consumption among migrants is predicted by need and predisposition factors, such as health condition and sociodemographic characteristics. In addition, mental health care consumption of migrants is predicted by acculturation characteristics. This result suggests an effect of cultural and migrant-specific factors in help-seeking behavior and barriers to mental health care facilities. CONCLUSIONS: Findings confirm the existence of migrant-specific mechanisms in health care consumption. Mental health care professionals should be aware of these. However, ignoring common ground for interventions unnecessarily creates distance between migrant groups and between migrant and indigenous Dutch groups.

Acculturation↗
PubMed1991

Outcome research on residential treatment: implications and suggested directions.

Reliance on single-sample designs without control groups has hampered the effectiveness of research on residential treatment for children and adolescents, although it has yielded useful information for conceptualization and postdischarge planning. More powerful comparative research designs between, within, and across programs are examined, and recommendations are made for their use in future outcome studies in this area.

Adolescent↗
PubMed2005

Gene-environment interactions in human diseases.

Studies of gene-environment interactions aim to describe how genetic and environmental factors jointly influence the risk of developing a human disease. Gene-environment interactions can be described by using several models, which take into account the various ways in which genetic effects can be modified by environmental exposures, the number of levels of these exposures and the model on which the genetic effects are based. Choice of study design, sample size and genotyping technology influence the analysis and interpretation of observed gene-environment interactions. Current systems for reporting epidemiological studies make it difficult to assess whether the observed interactions are reproducible, so suggestions are made for improvements in this area.

Environment↗
PubMed2004

The relationship between demographic and health-related factors on dental service attendance by older Australians.

OBJECTIVE: To determine factors associated with dental attendance by those of 60 years or older in a population-based sample. DESIGN: Cross-sectional national health survey. SETTING: The study used data from the Australian 1995 National Health Survey, which consisted of people interviewed by households. SUBJECTS AND METHODS: A total of 7,544 eligible respondents randomly selected by households from defined statistical areas.Main outcome measures The main outcome investigated in this study was having had a dental visit in the previous 12 months. MAIN RESULTS: Age, income, level of social disadvantage, level of education, uptake of private health insurance, smoking, exercise, self assessment of health and having a health concession card all independently influenced the attendance ratios. In combination, after adjusting for all other factors, factors associated with having visited a dentist for males were age, years of schooling, level of social disadvantage, exercise level index, possession of a health concession card and smoking status. Factors associated with having visited for females were age, education, exercise, smoking status and some levels of the interaction between possession of a health concession card and level of social disadvantage. CONCLUSIONS: The strong influence of age, education, exercise and smoking status indicated a need to target dental services towards those elderly persons in low attendance groups, which mostly represented disadvantaged groups.

Age Factors↗
PubMed2000

Low energy reporters vs others: a comparison of reported food intakes.

OBJECTIVE: To partition the food reports of low energy reporters (LERs) and non-LERs into four aspects-tendency to report a given food, frequency of reports per user, portion sizes per mention, and the qualitative (low-fat, low-sugar, low-energy) differences of the reports-in order to determine what differentiates them from one another. ASSESSMENT METHOD: Two non-consecutive 24h dietary recalls. Low energy reporting was defined as energy intake lower than 80% of estimated basal metabolic rate. SETTING: In-home personal interviews. SUBJECTS: 8334 adults from a stratified, multi-stage area probability sample designed to be representative of noninstitutionlized persons residing in households in the United States. RESULTS: Across all different types of foods, there are those food groups which LERs are less likely to report (28 of 44 food groups), those which they report less frequently when they do report them (15 of 44 groups), and those for which they report smaller quantities per mention (26 of 44). Qualitative differences in the food choices-that is, differences in fat, sugar, and/or energy content-were not so widespread (4 of 24 food groups). CONCLUSIONS: The practical application of analyses such as these is to improve the methods of gathering dietary data so that this kind of bias can be reduced. Further methodological research is needed to reduce the likelihood of respondents neglecting to mention foods and underestimating portion sizes.

Adult↗
PubMed2006

Associations of anthropometric characteristics with blood cholesterol fractions among adults. The Greek EPIC study.

OBJECTIVE: To explore the independent associations of body height, body mass index (BMI), waist circumference and hip circumference with high-density lipoprotein-cholesterol (HDL-cholesterol) and non-high-density lipoprotein-cholesterol (non-HDL-cholesterol), in a large general population sample. DESIGN: Cross sectional. SETTING: Urban and rural areas throughout Greece. SUBJECTS: In total,10 837 volunteers, 2034 men and 8803 women, aged 25-82 years, participants in the European Prospective Investigation into Cancer and Nutrition study (EPIC), who have never smoked and never been treated for dyslipidemia. INTERVENTIONS: None. RESULTS: The effect of height on non-HDL-cholesterol was opposite but in absolute terms almost as important as that of BMI with no gender interaction. Among women, hip circumference was inversely associated with non-HDL-cholesterol (standardized coefficient bst = -1.11, with standard error (s.e.)=0.42) and positively with HDL-cholesterol (bst = 0.85, s.e.= 0.12) whereas, waist circumference was inversely associated with HDL-cholesterol (bst = -1.16, s.e.=0.13) and strongly positively with non-HDL-cholesterol (bst = 8.83, s.e.= 0.45). Among men, associations were generally weaker (in absolute terms by about 50%) and for hip circumference the association with non-HDL-cholesterol was actually non significantly positive. CONCLUSIONS: Height was inversely associated with HDL and non-HDL-cholesterol implicating early life phenomena in the regulation of these variables. Larger hip circumference among women had beneficial effects on blood cholesterol fractions by increasing HDL-cholesterol and reducing non-HDL-cholesterol, whereas among men the relevant effects were less clear cut. The detrimental consequences of large waist circumference on both HDL (reduction) and non-HDL-cholesterol (increase) were also particularly marked among women. SPONSORSHIP: The European Prospective Investigation into Cancer and Nutrition (EPIC) is coordinated by the International Agency for Research on Cancer (World Health Organization) and supported by the Europe Against Cancer Program of the European Commission. The Greek segment of the EPIC study is also supported by the Greek Ministry of Health and the Greek Ministry of Education. This study was additionally supported by the fellowship 'Vassilios and Nafsika Tricha'.

Adult↗
PubMed2006

Putting the "landscape" in landscape genetics.

Landscape genetics has emerged as a new research area that integrates population genetics, landscape ecology and spatial statistics. Researchers in this field can combine the high resolution of genetic markers with spatial data and a variety of statistical methods to evaluate the role that landscape variables play in shaping genetic diversity and population structure. While interest in this research area is growing rapidly, our ability to fully utilize landscape data, test explicit hypotheses and truly integrate these diverse disciplines has lagged behind. Part of the current challenge in the development of the field of landscape genetics is bridging the communication and knowledge gap between these highly specific and technical disciplines. The goal of this review is to help bridge this gap by exposing geneticists to terminology, sampling methods and analysis techniques widely used in landscape ecology and spatial statistics but rarely addressed in the genetics literature. We offer a definition for the term "landscape genetics", provide an overview of the landscape genetics literature, give guidelines for appropriate sampling design and useful analysis techniques, and discuss future directions in the field. We hope, this review will stimulate increased dialog and enhance interdisciplinary collaborations advancing this exciting new field.

Animals↗
PubMed2005

Methods and the baseline situation in the field trial of home-based neonatal care in Gadchiroli, India.

In this paper, we describe the planning of the field trial and the methods used for collecting baseline health and ethnographic data in a rural field study site. We describe the study hypotheses, specific objectives, study design, sample size estimates, selection of study area, community consent, the organization of study teams, review mechanism, financial support and baseline data collection. Baseline population characteristics and vital statistics are presented. The qualitative information on traditional beliefs and practices prevalent in the study area revealed that parents felt powerless about newborn health and sickness. There was an enormous unmet need to reach the home-delivered neonates and their care-givers with the correct knowledge and health-care practices.

Home Care Services↗
PubMed2005

Effect of human milk fortifiers on bacterial growth in human milk.

BACKGROUND: As a component in human milk fortifiers (HMF), iron may equilibrate with human milk for as long as 24 hours, bind important bacteriostatic proteins, and potentially affect the host defense properties of human milk. OBJECTIVE: We compared bacterial growth in human milk prepared with each of two HMF differing in their content of iron. STUDY DESIGN: Samples of human milk obtained from mothers of premature infants were divided and mixed with one of two HMF and maintained at refrigerator temperature. Refrigerated milk samples were removed at 0, 24, and 72 hours for determination of total bacterial colony counts (TBCC). RESULTS: TBCC did not differ between groups but declined from 0 to 72 hours, p<0.001. CONCLUSION: These data suggest that differences in iron content, or other nutrients in HMF, do not affect bacterial growth in human milk. Storage of fortified human milk at refrigerator temperature for 72 hours results in decreased bacterial growth. As a component in human milk fortifiers (HMF), iron may equilibrate with human milk for as long as 24 hours, bind important bacteriostatic proteins, and potentially affect the host defense properties of human milk. We compared bacterial growth in human milk prepared with each of two HMF differing in their content of iron. Samples of human milk obtained from mothers of premature infants were divided and mixed with one of two HMF and maintained at refrigerator temperature. Refrigerated milk samples were removed at 0, 24, and 72 hours for determination of total bacterial colony counts (TBCC).

Bacteria↗
PubMed2006

New insight of amino acid-based dialysis solutions.

Malnutrition is a major complication of peritoneal dialysis (PD) and is associated with increased morbidity and mortality. Daily losses of proteins and amino acids (AAs) into dialysate contribute to this problem. Previous metabolic balance study demonstrated that treatment with 1.1% AA-based dialysis solution is safe and may improve protein malnutrition in continuous ambulatory peritoneal dialysis (CAPD) patients ingesting low protein intake. Other prospective studies also showed that AA solution can provide nutritional benefit for malnourished PD patients resulting in a significant improvement in some biochemical and/or anthropometric nutritional parameters. However, there are other studies showing no particular improvement in nutritional parameters after long-term use of AA solution. This may be related to the differences in the study design, sample size, methods used to assess nutritional status, and other factors such as dietary intake and comorbidities of study subjects. Published data will be reviewed to further emphasize the nutritional benefit of long-term use of AA solution in malnourished PD patients along with a brief discussion on the various reasons that may partly explain the different study results. We will also present the results of a longitudinal observational study evaluating changes in nutritional parameters following use of one exchange of 1.1% AA solution in malnourished Korean PD patients. A significant improvement of somatic protein status such as lean body mass (LBM) and hand grip strength was observed. No significant change in serum albumin level was noted. Patients with a positive estimated coefficient for LBM in the fitted regression model to the repeated observations over 1 year were classified as responders and patients with neutral or negative coefficient were considered as non-responders. Thirty-one out of 43 malnourished patients (72%) showed nutritional benefit based on the change of LBM. Hand grip strength and back lift strength were significantly higher in responders at baseline. Other baseline parameters did not differ between the two groups.

Amino Acids↗