Movement down a concentration gradient occurs fairly rapidly over short distances like a micron or so, like the size of a bacterium.

顺浓度梯度扩散在一微米左右的短距离内,相当迅速,一微米相当于一个细菌的大小

耶鲁公开课 - 生物医学工程探索课程节选

I think maybe the concluding lesson the central banks were institutions that emerged out of experience with bankers.

新工具的迅速扩散,我认为也许结论就是,中央银行是银行主。

耶鲁公开课 - 金融市场课程节选