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...
The moon has four basic phases: new moon, first quarter, full moon and third quarter. Since the moon doesn't emit its own light, it's only illuminated by sunlight. The dark section of the moon is the portion that is facing away from the sun, and only during a lunar eclipse is the Earth's shadow cast upon the moon.