Complete Headline: Missing Argentine submarine 'is located by US Navy and a new sonar signal heard' as rescuers race to the spot with oxygen due to run out imminently Search for missing Argentine submarine intensifies as the crew said to run out of oxygen today US Navy aircraft reportedly detected a 'heat stain from a metallic object' at a depth of about 230ft Separately, a rescue vessel allegedly reported hearing an infrasound sonar signal late Tuesday night Sub with 44 crew went missing last Wednesday while sailing from Ushuaia to naval base in Mar del Plata They sailed on Monday,...