A. No. The deadline to contribute to 401k or 403b is Dec 31st of the plan year.
However, you get up to April 15 of the following year to contribute to your IRA or Roth IRA account, the annual limit is $5,500 for 2013 and 2014, respectively. So please don't lose this chance to contribute to your 2013 IRA or Roth IRA account now!