DEHRADUN, India: Tibetans in exile celebrate the 90th birthday of spiritual leader the Dalai Lama next week, an occasion overshadowed by uncertainty about the future of the role and what it means for their movement. The charismatic Nobel Peace Prize-winning Buddhist – who Tibetans say is the 14th reincarnation of the 600-year-old post – will reveal if there will be another Dalai Lama after him. The inevitable change ahead brings wider concerns for Tibetans over the struggle to keep their identity alive after generations in exile, following a failed 1959 uprising against Chinese rule.