41.   Lawrence Turnbull, a top CIA seismologist, has long warned of clever ways to evade detection of nuclear explosions.

42.   Led by Republicans, the Senate rejected the global ban on nuclear explosions, and it is unclear whether the United States would now accuse Russia of violating it.

43.   Meanwhile, Sandia, which has years of experience using supercomputers to simulate nuclear explosions, will help Celera develop software to analyze biological data.

44.   National security officials said that the kind of machines currently used to simulate nuclear explosions, however, will remain strictly controlled.

45.   Not until the late Eighties did the first data dribble out about peaceful nuclear explosions.

46.   Nuclear explosions could have destroyed the Atlantean civilization and triggered an ice age.

47.   On Monday, the nations of the world observe a ban on underground nuclear explosions.

48.   Once, it meant the intense conflagration created by a nuclear explosion.

49.   One famous television commercial featured a young girl picking a daisy whose image gave way to footage of a mushroom cloud from a nuclear explosion.

50.   Participating cross-mythically in cultures that encompass the globe, the nuclear explosion must itself become a primary myth in the postnuclear world to come.