热带雨林中居住的不那么鲜艳的鸟类和动物，往往依赖于视觉以外的信号形式，尤其是长距离的信号。

Less colorful birds and animals that inhabit the rain forest tend to rely on forms of signaling other than the visual, particularly over long distances.

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在森林中，视觉信号只能在没有树木遮挡的地方在短距离内被看到。

In forests, visual signals can be seen only at short distances, where they are not obstructed by trees.

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一个普通的手机可以发送信号的距离为70公里。

An ordinary cellphone may send a signal at the distance 70km.

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Here, what's different between autocrine and paracrine is that there's some distance between the cell that produces the signal and the cell that receives the signal, but it's not too great a distance because the blood system doesn't have to be involved.

自分泌和旁分泌的区别在于,旁分泌中,产生信号的细胞和接收信号的细胞,之间存在着一定的距离,但这个距离并不远,因为血液系统并不参与

耶鲁公开课 - 生物医学工程探索课程节选