Russian authorities on Wednesday released Brazilian Greenpeace activist Ana Paula Maciel from prison in Saint Petersburg after she was bailed, the first of the group's campaigners arrested in Russia to walk out of jail, the group said. "Ana Paula Maciel has left prison! She is free! The first of the Arctic 30," the Russian Greenpeace office wrote on Twitter, as hearings continued into the 30 activists charged with hooliganism over their protest against Arctic oil drilling.