BACKGROUND Many studies conducted in health and social sciences collect individual level data as outcome measures. Usually, such data have a hierarchical structure, with patients clustered within physicians, and physicians clustered within practices. Large survey data, including national surveys, have a hierarchical or clustered structure; respondents are naturally clustered in geographical uni...

Based on a Wiener process approximation, a sequential test for the bundle strength of filaments is proposed and studied here. Asymptotic expressions for the OC and ASN functions are derived, and it is shown that asymptotically the test is more efficient than the usual fixed sample size procedure based on the asymptotic normality of the standardized form of the bundle strength of filaments,

Background: Adequate sleep is essential for proper mental function. The aim of this study was to investigate the relationship between the intensive care unit nurses' psychological capital and their quality of sleep.   Methods: This was a descriptive correlational study. The study sample included 200 nurses from the educational medical centers affiliated to Iran University of Medical Sciences ...

Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/about/terms.html. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your perso...

The enzyme-linked immunosorbent assay (ELISA) is often used to measure protein levels in plasma and other solutions. In order for the assay to be quantitative, a standard curve must be prepared for each assay. Technical blunders in preparing the standard curve can render otherwise representative sample values useless. In order to recover these data, a protocol has been developed whereby a new s...