US President Barack Obama and Vice-President Joe Biden's families wave to the audience at the conclusion of Obama and Biden's acceptance of the Democratic National Convention's nomination to run for a second term as president and vice-president at the Time Warner Cable Arena in Charlotte, North Carolina, on September 6, 2012 on the final day of the DNC.  AFP PHOTO  Stan HONDA        (Photo credit should read STAN HONDA/AFP/GettyImages)