Placental transfer of the HIV protease inhibitor darunavir was investigated in 5 term human cotyledons perfused with darunavir (1,000 ng/ml) in the maternal to fetal direction. The mean (± the standard deviation [SD]) fetal transfer rate (FTR) (fetal/maternal concentration at steady state from 30 to 90 min) was 15.0%±2.1%, and the mean (±SD) clearance index (darunavir FTR/antipyrine FTR) was 40...

convolution each of the BOLD responses with a single universal transfer function, modeled BOLD signals were generated which when differenced with the measured BOLD signals showed residual signals which were smaller than the measurement uncertainty. The root mean square (RMS) of the residual signal (left number) was compared with the averaged standard deviation (SD) of the measured data (right n...

In most clinical and experimental studies, the standard deviation (SD) and the estimated standard error of the mean (SEM) are used to present the characteristics of sample data and to explain statistical analysis results. However, some authors occasionally muddle the distinctive usage between the SD and SEM in medical literature. Because the process of calculating the SD and SEM includes differ...

As a nonstatistician, I have watched the discussion on this topic with interest (1–8). Dr. Curren-Everett and others make a clear statement that variability of results should always be reported using the standard deviation (SD) and not the standard error (SE). Others cited above variously agree and disagree with the guidelines published by Dr. Curren-Everett and others. The reasoning provided i...

The World Health Organization (WHO) defines osteopenia as a bone density between 1 and 2.5 standard deviation (SD) below the bone density of a normal young adult Iqbal 2000. Osteoporosis is defined as 2.5 SD or more below that reference point Iqbal 2000. Bisphosphonates are a group of medications used to treat osteoporosis, Padget's disease of bone, and osteopenia. We report a woman who develop...

Ticks are obligate blood feeding ectoparasites that transmit a wide variety of pathogenic microorganisms to their vertebrate hosts. Amblyomma sculptum is vector of Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever (RMSF), the most lethal rickettsiosis that affects humans. It is known that the transmission of pathogens by ticks is mainly associated with the physiology of...

Rickettsia rickettsii is a tick-borne obligate intracellular bacterium that causes Rocky Mountain Spotted Fever (RMSF). In Brazil, two species of ticks in the genus Amblyomma, A. sculptum and A. aureolatum, are incriminated as vectors of this bacterium. Importantly, these two species present remarkable differences in susceptibility to R. rickettsii infection, where A. aureolatum is more suscept...

A Nephelometric turbidimeter coupled with a data acquisition unit was used to measure turbidity every second. The standard deviation (SD) of the measured turbidity was proportional to the square root of the floc size; a greater SD indicated larger floc sizes. Than the image analysis (Matrox Inspector V2.2) was used to measure the mean particle size to confirm whether Nephelometric technology is...

An important part of statistical analysis, perhaps the most important part, is the identification and quantification of sources of variation. For example, in a t-test the variation between groups is compared with variation within the groups to see if the former can be explained by the latter alone. The main tool for measuring variation is the standard deviation (SD), although it is sometimes us...