ScienceDaily: Teenagers’ Use Of Cell Phones After Bedtime Contributes To Poor Sleep
Science Daily — The use of modern means of interpersonal and mass communication has become an essential part of being young. Technology has enabled two people to connect with each other virtually anywhere and at any time, a privilege that, according to new research, is often abused by youngsters and cutting into their sleep time.

A new study finds that cell phone use after bedtime is very prevalent among adolescents, and its use is related to increased levels of tiredness after one year.

uhm, duh?