Preexisting computerized databases are potentially valuable sources of epidemiologic data. Since such databases are infrequently created specifically for etiologic research, data may be available for the exposure of interest and, through record linkage, for the endpoint of interest, but lacking for potential confounders. Because of the size of these databases, two-stage sampling is an efficient...

Methods for the analysis of unmatched case-control data based on a finite population sampling model are developed. Under this model, and the prospective logistic model for disease probabilities, a likelihood for case-control data that accommodates very general sampling of controls is derived. This likelihood has the form of a weighted conditional logistic likelihood. The flexibility of the meth...

Binocular deficits are relatively common within a typical sample of observers. This has implications for research on binocular vision, as a variety of stereo deficits can affect performance. Despite this, there is no agreed standard for testing stereo capabilities in observers and many studies do not report visual abilities at all. Within the stereo literature, failure to report screening and s...

A quantitative, descriptive, cross-sectional survey was carried out in the Limpopo Province to identify the perceptions of student nurses, nurse educators and unit supervisors concerning student nurses’ clinical accompaniment in this province. The research objective was to determine whether or not clinical accompaniment of student nurses in the Limpopo Province was perceived to be adequate by t...

The study examined the patterns and determinants of agricultural credit use among farming households in Oyo State, Nigeria. The primary data used for the study were obtained from a cross sectional survey of 114 farm households drawn by multi-stage random sampling technique. Both descriptive statistics and multiple regressions were used to analyze the data obtained. The study revealed that 47.4%...

The authors present 2 studies to explain the variability in the duration of emotional experience. Participants were asked to report the duration of their fear, anger, joy, gratitude, and sadness episodes on a daily basis. Information was further collected with regard to potential predictor variables at 3 levels: trait predictors, episode predictors, and moment predictors. Discrete-time survival...

BACKGROUND In population-based observational studies, non-participation and delayed response to the invitation to participate are complications that often arise during the recruitment of a sample. When both are not properly dealt with, the composition of the sample can be different from the desired composition. Inviting too many individuals or too few individuals from a particular subgroup coul...

Metagenomic studies have become increasingly popular. They allow for the estimation of biodiversity in complex populations. This diversity presents an enormous but largely unexpected genetic and biological pool and can be exploited for the recovery of novel genes, entire metabolic pathways and their products. Generally metagenomic study is a genomic analysis of organisms by direct extraction an...