The systems called on can be rigorously mathematical, or intuitive and personal.
The screeners were trained to operate Explosive Detection Systems, called E.D.S.
Light reactions comprise two interdependent systems, called photosystems I and II.
The European rabbit constructs the most extensive burrow systems, called warrens.
These cryptographic systems, called end-to-end (E2E) secure, are the preferred systems from a security point of view.
Immunity from disease is actually conferred by two cooperative defense systems, called nonspecific, innate immunity and specific, acquired immunity.
The latter feature is offered by systems called videotex, which were first introduced in Great Britain and West Germany.
The safety systems, called positive train control (PTC), were required on commuter and some commercial rail lines in 2008 by Congress in the Rail Safety Improvement Act.
Governments continue to debate the practicality of magnetic-levitation transportation systems -- wheel-less trains that hover above the tracks and use magnetic propulsion systems called linear induction motors.
The touch-screen computer systems, called direct-recording electronic, which are the most modern and potentially accurate systems, cost $3,500 per unit.
Lined up against it are newer industry players like Bloomberg and Instinet, companies that run the increasingly popular alternative trading systems called electronic communications networks, or E.C.N.'s.
