41.   The water appears to come from countless comets that have pounded the lunar surface over millions of years, said project scientist Alan Binder.

42.   There is plenty to study, in the meantime, about aspects of the dizzyingly complex puzzle that is the atmosphere, many scientists said.

43.   These, say the scientists, combine in mild weather to intensify a terrifying teen-ager lust for noise.

44.   This summer, several scientists said, will be a test of just how long-lasting, or fleeting, the West Nile virus scare will be.

45.   Two of the cases reported today involve a defect in the gene for leptin, the first such leptin defect found, said the scientists.

46.   Whatever the exact time, it did not take long, the Hubble scientists said, before these primeval galaxies resembled similar elliptical galaxies today.

47.   When closest to the Sun and its heat, as Pluto is currently, surface ice turns gaseous and expands the atmosphere, scientists said.

48.   When the animals were given antibodies that blocked resistin, their sugar and insulin abnormalities improved, said the scientists.

49.   While previous studies had implicated homocysteine as risk factor, the strength of its interaction with other risk factors was not appreciated, the scientists said.

50.   A big loser was the U.S. election system, which appears more fraught with imperfections than ever before, said political scientist Larry Sabato of the University of Virginia.