FOR Ricardo Moraes, a veteran photographer who for 11 years has documented for Reuters life in Rio de Janeiro's often dangerous cinderblock slums known as "favelas", work began at about 6 a.m. on Thursday, when he heard a radio report of a hostage situation in Sao Carlos, a sprawling tangle of hillside homes near the city centre. The images he would capture - a young woman, kneeling over her husband's body, overcome with grief and surrounded by heavily armed police - ultimately would appear on the front pages of Brazil's two largest newspapers. They resonated in a city fed up…