Status of blood banking and the blood supply in Afghanistan.

Background: As a result of more than 20 years of war in Afghanistan, its blood supply system has been damaged. We carried out an assessment of that blood supply system to determine the type and extent of assistance needed to increase blood availability and safety.

Study Design And Methods: An assessment tool was developed, daily activities in Afghanistan were observed, and key personnel were interviewed.

Spatial dependence of the nonlinear BOLD response at short stimulus duration.

Most functional magnetic resonance imaging studies use linear models to predict the measured response by convolution of an impulse response with the stimulus profile. Using very short visual presentation times (<2 s), deviation from the linear model in the measured BOLD data from the human brain was found for the response integral, amplitude, and width. In this study, high temporal and spatial resolution were used to quantify nonlinear effects and investigate the spatial dependence.