For a good night of sleep, consider getting your circadian rhythm back in sync with the sun. Here’s how to do it.

Scientists discovered trees use a biological clock to time growth. Changing this clock helps trees grow better and adapt to new environments.

Could it happen?

Federal law prohibits the president from telling the I.R.S. to conduct specific tax investigations. 5 min read Columbia Vows to Reject Any Trump Deal That Threatens Its Independence 4 min read ...