Thomas Perlmann (C), Secretary of the Nobel Committee for Physiology or Medicine, announces the winners of the 2017 Nobel Prize in Physiology or Medicine during a press conference in Stockholm, Sweden, Oct. 2, 2017. Three scientists share 2017 Nobel Prize in Physiology or Medicine, the Nobel Committee announced on Monday in Stockholm. The Nobel assembly at the Karolinska Institute has decided to award the 2017 physiology or medicine prize jointly to Jeffrey C. Hall, Michael Rosbash and Michael W. Young for their discoveries of molecular mechanisms controlling the circadian rhythm. (Xinhua/Shi Tiansheng)