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...
â¢ Great Red Spot â giant storm system over 400 years old. Could fit three Earths inside it. â¢ Thin, dark ring system, invisible to even powerful telescopes. â¢ Four Galilean Moons: Ganymede (largest moon in Solar System); Callisto (most cratered moon in Solar System); Io (most volcanic moon); Europa (may have ocean beneath its icy surface).