A vented piston comprises a plunger having a front side and a rear side, a venting passage extending between the front side and the rear side, and a cap located adjacent the front side. At least one multitrack write head having N write elements arranged along a track width direction in an integral fashion and at least one multitrack read head having L read elements arranged along the track width direction in an integral fashion are formed on the rotary drum. The debit card platform establishes a telephone connection between the caller and the content provider to enable the content provider to provide a service to the caller through the telephone connection. In this manner, the system is able to electrically characterize individual or combined layers of the sample as well as embedded junctions. Accordingly, this disclosure includes, but is not limited to, medical devices, means of constructing medical devices, and methods of imaging medical devices using magnetic resonance and other technologies. The technique includes determining whether at least one of the interconnected devices needs power after the allocation of power among the neighbors and selectively further allocating power among the neighbors in a direction along the tree toward the root based on the determination.