Weather improves but clock ticks for Argentine submarine search

By Walter BianchiMAR DEL PLATA, Argentina (Reuters) - The search for a missing Argentine submarine and its 44-member crew was helped by calmer seas on Tuesday, but there were no new clues about its location and worries multiplied because the vessel may be running low on oxygen, a navy spokesman said.The ARA San Juan was en route from Ushuaia, the world's southernmost city, to its base in Mar del Plata and was about 300 miles (480 km) off the coast when it gave its last location on Wednesday, soo