? WELCOME: US president Barack Obama and first lady Michelle Obama are greeted upon their arrival at Waterkloof Air Base, yesterday, in Centurion, South Africa. The President is in South Africa, embarking on the second leg of his three-country African journey. Today he is to meet with South African president Jacob Zuma. The two men are then expected to hold a joint news conference. Mr Obama said he was not certain whether he would be able to see Mr Mandela, who is gravely ill, during his visit. Following his visit to South Africa, Mr Obama is scheduled to go to Tanzania. He travelled to South Africa from Dakar, Senegal