More than 20 years after the AIDS epidemic arrived in the United States, a significant proportion of African Americans embrace the theory that government scientists created the disease to control or wipe out their communities, according to a study released today by Rand Corp. and Oregon State University. That belief markedly hurts efforts to prevent the spread of the disease among black Americans, the study's authors and activists said. African Americans represent 13 percent of the U.S. population, according to Census Bureau figures, yet they account for 50 percent of new HIV infections in the nation, according to the Centers...