The University of North Carolina School of Medicine conducted a study that shows that by training local birth attendants in a method promoted by the World Health Organization, the number of still births was reduced by about 30 percent.

VOA: standard.2010.05.11

It's a more powerful method than something called a cross-sectional study, and I'll come back in a later lecture and talk about these in more detail, but a cross-sectional study means you're taking a snapshot of a population of people at one time.

这种方法比所谓的横断面研究更加有效,我将在以后的课中,再仔细讨论这个问题,但横断面研究是指,你一次记录下一群人的状况

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

It's a more powerful method than something called a cross-sectional study, and I'll come back in a later lecture and talk about these in more detail, but a cross-sectional study means you're taking a snapshot of a population of people at one time.

这种方法比所谓的横断面研究更加有效,我将在以后的课中,再仔细讨论这个问题,但横断面研究是指,你一次记录下一群人的状况

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选