If their population is tracked through time, it will be seen to be particularly unstable—soaring and plummeting in irregular cycles.

如果对它们的数量进行时间记录，就会发现它是很不稳定的——以不规则的周期急剧上升下降。

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AIM: to investigate the association between the matrix metalloproteinase-9 (MMP-9) gene C1562T polymorphism and the susceptibility to unstable angina pectoris (UAP) in Han population of South China.

目的：了解基质金属蛋白酶9基因C1562T多态性与中国南方汉族人群不稳定型心绞痛易感性的关系。

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Medicaid programs attempt, mostly through heroic individual efforts, to serve a desperately needy population of the poor, chronically ill, mentally unstable, and recklessly pregnant.

FORBES: Fools' Gold Rush: Obamacare And The Medicaid "Opportunity"