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...
Cumulonimbus Clouds (thunderclouds). Cumulonimbus is a type of cloud that is tall, dense, and usually dark. These clouds form thunderstorms, and can create severe weather conditions, such as heavy rain, damaging winds, hail, lightning, and tornadoes. A cumulonimbus cloud that progresses to an intense, long-lived form is known as a supercell.