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.
Eventually, children with Batten disease become blind, bedridden, and demented. Batten disease is often fatal by the late teens or twenties. Batten disease is named after the British pediatrician F. E. Batten who first described it in 1903. Also known as Spielmeyer-Vogt-Sjogren-Batten disease, it is the most common form of a group of disorders called Neuronal Ceroid Lipofuscinoses (or NCLs).
Tay shares the diseaseâs title with New York neurologist Bernard Sachs, who described the cellular changes present in the disease as well as its potential for heritability, shortly after Tayâs observation.