61.   Centuries passed and humans on Earth began to detect the presence of alien vessels on the long-range scanners.

62.   Experts detected the presence of PCBs, polychlorinated biphenils, a toxic substance formerly used in insulating material, in the building.

63.   He said devices worn by workers detected the presence of methane gas, and the explosion occurred after evacuation began.

64.   He too detected the presence of Chaos Emeralds in the island.

65.   In New York, Pataki shut down his Manhattan office after an initial test detected the presence of anthrax.

66.   Instead, the agency said the tests sometimes fail to detect the presence of HIV.

67.   Instruments on the spacecraft earlier had detected the presence of hydrogen, suggesting the crater could contain ice.

68.   Its presence was detected by its faint ultraviolet light, which is invisible to conventional telescopes.

69.   Meanwhile, the Agriculture Department will begin certifying new tests designed to detect the presence of biotech ingredients in food.

70.   Microbiological tests to detect the presence of faecal coliform were also carried out.