The two photocells are linked to the Tree: the Pre-Stage, and the Stage lights. When the car inches forward and blocks the first photocell, the Pre-Stage light comes on, indicating that the driver is close to the starting line. Most tracks have a rollout, or distance between the Pre-Stage and Stage beams of 6-8.
Batten disease is named after the British pediatrician Frederick Batten, who first described it in 1903. Also known as Spielmeyer-Vogt-SjÃ¶gren-Batten disease, it is the most common form of a group of disorders called neuronal ceroid lipofuscinosis (or NCLs).
Biographical Note for ampulla of vater Vater, Abraham (1684â1751), German anatomist. Vater was a professor of anatomy and botany and later of pathology and therapeutics at Wittenberg. In 1710 he first noted the ampulla that has been named after him, but he did not publish a description of it until 1720. In 1717 he described the terminal capsules of certain sensory nerve fibers.