The Columbia Training School — pleasant on the outside, austere on the inside — has been home to 37 of the most troubled young women in Mississippi.These are harsh and disturbing charges — and, in the end, they were among the reasons why state officials announced in February that they will close Columbia. But they aren't uncommon.Across the country, in state after state, child advocates have deplored the conditions under which young offenders are housed — conditions that include sexual and physical abuse and even deaths in restraints. The U.S. Justice Department has filed lawsuits against facilities in 11 states for supervision that is either abusive or harmfully lax and shoddy.Still, a lack of oversight and nationally accepted standards of tracking abuse make it difficult to know exactly how many youngsters have been assaulted or neglected.The Associated Press contacted each state agency that oversees juvenile correction centers and asked for information on the number of deaths as well as the number of allegations and confirmed cases of physical, sexual and emotional abuse by staff members since Jan. 1, 2004. According to the survey, more than 13,000 claims of abuse were identified in juvenile correction centers around the country from 2004 through 2007 — a remarkable total, given that the total population of detainees was about 46,000 at the time the states were surveyed in 2007.Just 1,343 of those claims of abuse identified by the AP were confirmed by various authorities. Of 1,140 claims of sexual abuse, 143 were confirmed by investigators.Experts say only a fraction of the allegations are ever confirmed. These are some of the most troubled