What about sleep? In slow-wave deep sleep, our glial cells rinse cerebral spinal fluid throughout our brains, 关于睡眠呢？在慢波深度睡眠时，我们的神经胶质细胞冲洗着我们大脑中的脑脊液， clearing away metabolic waste that accumulated in ou
February 28, 2008 THE PRESIDENT: Good morning. Laura and I, as you know, recently came back from Africa, where we saw firsthand how the Emergency Plan for AIDS Relief is saving lives. I had a chance t
Dear Dad, 亲爱的爸爸， I'm putting this in a letter because phone calls have a way of disappearing in the whatever it is. 我把想说的话写进信里，是因为通过电话倾诉总感觉缺点什么。 I'm trying to put into words what I feel most deeply, n
Hello, everyone. Nine months ago, I announced the Reach Higher Career App Challenge. We called on app developers, educators, entrepreneurs, and others to put their heads together and design new mobile
