Older people must be given more chances to learn if they are to contribute to society rather than be a financial burden, according to a new study on population published recently.

根据最近发表的一项关于人口的研究，如果老年人要对社会作出贡献而不是成为经济负担，就必须给他们更多学习机会。

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It requires districts to have the same population, so that their boundaries must be redrawn after every census (ie, once a decade).

这就要求每个选区做到人口数目一致，每次人口普查(十年一次)之后重新划分选区。

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However, it must be stressed that public health authorities must always balance the health risk to the population against other undesirable consequences.

然而，必须要强调的一点是，公共卫生主管当局必须始终权衡人口卫生风险和其它不良后果。

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The required cell population that must be targeted (killed or controlled) to cure or control cancer, is the set of all malignant cells that could evolve.

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That's nearly half the population, who must be resettled before the winter rainy season if they are to plant the single annual rice crop.

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But while cases like Kaiba's are a medical boon, both Terzic and the UM researchers stress that this and other regenerative procedures must be replicated in a wider patient population.

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