This new study combined a large number of previous studies and concluded that a lack of social interactions ranks right up with smoking,obesity, and alcoholism as a risk factor for death.

VOA: standard.2010.07.29

Essentially for our purposes here, you can just think of it as a conversion factor.

就是去掉库伦标签，这就是我们。

麻省理工公开课 - 化学原理课程节选

And one factor in Parkinson's is too little of a neurotransmitter known as dopamine.

引起帕金森症的一个病因,便是严重缺乏一种叫做多巴胺的神经递质

耶鲁公开课 - 心理学导论课程节选