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...
(Å­m'brÉ) Plural umbras or umbrae (Å­m'brÄ) The darkest part of a shadow, especially the cone-shaped region of full shadow cast by Earth, the Moon, or another body during an eclipse. In a full lunar eclipse, which generally lasts for one or two hours, the entire disk of the Moon is darkened as it passes through the umbra.