Because on second exposure there's another population of cells that I haven't mentioned before that remain after the primary exposure and those are called memory cells, they're down here.

因为在再次免疫中,有另外一些细胞,我之前并没有提到过它们,在初次免疫结束后保留下来的细胞,被称为记忆细胞,它们在下面

耶鲁公开课 - 生物医学工程探索课程节选

I'm going to have 2 still, and then this S1 is going to become a 1, and this S1 here is going to become a plus B S2, everyone happy with that?

还保留,S1求导后是1,这里的S1会变成B*S2,大家都会吧

耶鲁公开课 - 博弈论课程节选