Article Photos: Zoo: Liver problem to blame for panda cub death 1/4

  FILE - This Dec. 19, 2011 file photo shows Mei Xiang, the female giant panda at the Smithsonian's National Zoo in Washington. The zoo will disclose the cause of death of Mei Xiang's 6-day-old cub at a news conference Thursday morning, Oct. 11, 2012. The cub, believed to be female, died Sept. 23, 2012. (AP Photo/Susan Walsh, File)