Transcranial Doppler Assessment of Cerebral Flow Velocity During Cognitive Tasks Roger E. Kelley, MD; Jen Y. Chang, MS; Nancy J. Scheinman, PhD; Bonnie E. Levin, PhD; Robert C. Duncan, PhD; and Shih-Chang Lee, PhD Background and Purpose: The purpose of this study was to assess the ability of transcranial Doppler ultrasonography to detect selective circulatory changes during cognitive activity. Methods: We measured cerebral artery flow velocity in 21 normal volunteers by transcranial Doppler ultrasonography during rest followed by cerebral activation. Mean and peak systolic
Neptune has dark storms and eight named moons, although there are more than 8 moons. Source(s): My memory http://burro.astr.cwru.edu/stu/neptune_m...
In this demo, the New Moon occurs at the beginning of Day 1. A New Moon appears completely dark because the part of the Moon that is visible is the Moon's night side. During the next week (Days 1-7), less than 50% of the Moon's visible face is illuminated and we see a Crescent Moon. After one full week (Day 8), exactly 50% of the Moon's visible face is illuminated. We see a First Quarter Moon.