41.   The people who raised him used smoke signals for long-distance communication, or they blew through the hollowed-out horns of bulls, he said.

42.   The primary system is dead reckoning, but a soft tire can throw off the readings so the satellite signal is used as a cross-check.

43.   The robot carries a pair of Global Positioning System receivers and uses signals from orbiting satellites to pinpoint its location.

44.   Their interest will prompt broadcasters to start using the signals, he predicted.

45.   These unconscious emotional signals are then used to help select the best course of action.

46.   They use fewer signals than women and even fewer overt or sexual gestures, such as caresses or hiking their skirt up.

47.   This Time Machine keeps track of time down to the millisecond by automatically setting itself using shortwave signals from the U.S. Atomic Clock.

48.   Two new medical studies conclude that cellular telephones that use digital signals can interfere with the rate of pacemakers.

49.   Two Italian players were accused of using illegal signals.

50.   Using hand signals, he asked the French logistics manager whether he could keep the sturdy Japanese strapping that had defied gravity.