MAR DEL PLATA, Argentina (Reuters) - Seven satellite calls that Argentine officials detected recently believed to have come from a navy submarine missing in the South Atlantic have not helped to determine the vessel s location, a navy official said on Sunday.  We analyzed these signals, which as we know were  intermittent and weak,  said Gabriel Galeazzi, a naval commander.  They could not help determine a point on the map to help the search.   