It also is possible, again it's just speculation, that population pressure might well be greater in the cities that did the colonizing.

再一次,只是猜测,也很有可能,这些进行殖民的城市,人口压力相对大

耶鲁公开课 - 古希腊历史简介课程节选

So in a town that's the size of new Haven with a population of let's say 100,000 people in just the immediate New Haven area, there might be 20 of these instances of very severe form of polio per year, 20 crippled children would result.

在一个像纽黑文这么大的城市里,大约有十万人口,生活在纽黑文地区的人当中,每年可能就会有二十人,感染到这种急性传染病,可能会导致二十个孩子残疾

耶鲁公开课 - 生物医学工程探索课程节选