Rajshahi University (RU) will go on a 15-day winter vacation from December 31, university sources said.Regular classes and examinations will remain closed from December 31 to January 14 while administrative activities will remain closed from January 1 to 7, confirmed public relations office of the university.The residential students have been asked to leave halls on December 31 by 12 noon. The halls will reopen for students on January 7.