The United Nations has sounded the alarm bell over a potentially catastrophic humanitarian situation in Nigeria's Borno State. It says some 50,000 children under the age of five could starve to death. In South Africa, Olympic athlete Oscar Pistorius has been sentenced to six years in jail for the murder of his girlfriend Reeva Steenkamp. And in South Sudan, renewed violence has thrown the recent peace deal into doubt. Dozens of people died last week in clashes in the town of Wau.