1517-9702 1517-9702 S1517-97022014000401015 10.1590/s1517-97022014051453 Chile 00 12 2014 00 12 2014 40 4 1015 1028

11 11 113-30 1 31 31 113-35 2 48 48 33-70 3 3 143-52