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).
Commonly referred to as Batten disease, the Neuronal Ceroid Lipofuscinoses (NCLs) denote several different genetic life-limiting neurodegenerative diseases that share similar features. Although the disease was initially recognised in 1903 by Dr Frederik Batten, it wasnât until 1995 that the first genes causing NCL were identified.