An award-winning Iranian nuclear scientist, who disappeared last year under mysterious circumstances, has defected to the CIA and been resettled in the United States, according to people briefed on the operation by intelligence officials. Shahram Amiri, a nuclear physicist in his early 30s, went missing last June three days after arriving in Saudi Arabia on a pilgrimage, according to the Iranian government. The officials were said to have termed the defection of the scientist, Shahram Amiri, "an intelligence coup" in the continuing CIA operation to spy on and undermine Iran's nuclear program. A spokesperson for the CIA declined to comment....