The effects of optical blur on motion and texture perception.

Purpose: The purpose of this study is to determine how decreased visual acuity affects performance on tasks of motion and texture perception.

Methods: Positive diopter lenses were used to match three subjects at five levels of decimal visual acuity (DVA) ranging from an uncorrected DVA of 1.6 to the lowest DVA of 0.

The effect of disrupting the human magnocellular pathway on global motion perception.

The purpose of this study was to demonstrate the effect of human magnocellular (M)-pathway disruption on global motion perception. Coherence thresholds for global motion direction discrimination in random dot patterns were determined at slow and moderate dot speeds: (1) after adaptation to full-field sinusoidal flicker or a steady gray field, and (2) on a red or a gray background. Adaptation to flicker and a red background increased motion coherence thresholds relative to the gray baseline conditions at both dot speeds.

Implementation of the Ottawa Knee Rule for the use of radiography in acute knee injuries.

Context: The Ottawa Knee Rule is a previously validated clinical decision rule that was developed to allow physicians to be more selective and efficient in their use of plain radiography for patients with acute knee injuries.

Objective: To assess the impact on clinical practice of implementing the Ottawa Knee Rule.

Design: Controlled clinical trial with before-after and concurrent controls.

Safety and use of autologous blood donation during the third trimester of pregnancy.

To examine autologous blood donation during the third trimester of pregnancy, records of 272 blood donors who donated by standard procedures were reviewed. The incidence of vasovagal reactions at autologous donation was 2.1% (7/341) versus 1.

Fetomaternal hemorrhage associated with umbilical vein thrombosis. Case report.

Antenatal thrombosis of the umbilical vein is usually a fatal condition for the fetus or neonate. The probable pathophysiology of this condition and its relationship to fetomaternal hemorrhage is discussed. A systematic study of the entire umbilical cord should be done when fetomaternal bleeding is diagnosed.