TEXT: A seaman looks out from a checkpoint window that shows the reflection of a fence blanketed with national flags and homemade signs in support of submarine crew members of the missing  ARA San Juan, at the naval base in Mar de Plata, Argentina, Thursday, Nov. 23, 2017. More help was arriving in a multinational search Thursday for the Argentine submarine with 44 crew members as concern grew that the vessel's oxygen supply could soon start to run out. (AP Photo/Esteban Felix)