A rib bone and a piece of cloth supposedly recovered after Joan of Arc was burned at the stake are probably not hers, according to experts trying to unravel one of the mysteries surrounding the 15th century French heroine.Eighteen experts began a series of tests six months ago on the fragments reportedly recovered from the pyre where the 19-year-old was burned for heresy.Although the tests have not been completed, findings so far indicate there is "relatively little chance" that the remnants are hers, Philippe Charlier, the head of the team, told The Associated Press on Saturday.The fragment of linen from...