Cuba's Fidel Castro is "very alert" and resting after stomach surgery, a senior aide said on Wednesday, but the man who has governed for 47 years has not appeared in public since standing down temporarily this week. There was also no sign of younger brother Raul, who took over power provisionally on Monday from Castro, 79, the world's longest-ruling head of government.Ricardo Alarcon, head of the national assembly and a close Castro aide, told a U.S. radio program he had spoken to the veteran communist leader on Tuesday. "He's in, I would say, a normal period of recovery after an important surgery, that's essentially what I would say, but very alive and very alert," Alarcon told the Democracy Now! show.