If the temperature drops below a certain level it sends a signal, 'turn on the heat', and that signal stays on until it gets a negative signal to turn off.

如果温度降到一定程度以下时,探测器会发送一个信号,打开加热器,直到加热器再收到关闭的信号,它就会一直开着

耶鲁公开课 - 生物医学工程探索课程节选

Those same estimates say that if you could turn that around, that if the world could eat the recommended level of fruits and vegetables, that you'd reduce the prevalence of heart disease by 31%.

反过来说就是,如果大家都能食用适量的水果和蔬菜,那心脏病的普遍性将降低31%

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选