A control unit for a ventilator is arranged to receive, from each of a number of electrode pairs on an esophageal catheter a bioelectric signal having an ECG component. The ride-on, or ride-on vehicle, includes a frame having a seat adapted to support a child, and a drive assembly with a battery-powered motor assembly. The self-locking and adjustable apparatus can be used alone to apply circumferential force or with fasteners to apply linear force. The result of the second exclusive OR operation is stored. The invalid portion of the first stripe and a remainder of the first stripe are maintained until the first stripe is reclaimed.