RIO DE JANEIRO — Military police in Rio de Janeiro are stepping up security after projectiles struck a bus carrying journalists to the main Olympic Park, the organizing committee for the games said. While authorities said it was not immediately clear what struck the bus, a retired U.S. Air Force captain who now writes about women’s basketball said she was certain it was gunfire.Britain’s Press Association on Wednesday quoted Lee Michaelson, who was on the bus Tuesday, as saying that she instinctively hit the floor when she heard the sound of gunfire and “hollered to the others … ‘Get down! Get down! We are taking fire.’”(nypost.com)…[+]