This study examines the transition of a population to stability following a shift to a new fixed set of vital rates. Specifically, the authors develop a simple discrete population model and use it to derive an explicit solution for the birth trajectory. "The new vital rates interact with the population's initial age composition and generate birth waves whose amplitude and attenuation depend on the ratio of ultimate to initial growth and on the new pattern of stable net maternity. A greater change in growth and a later stable net maternity pattern produce larger fluctuations in the number of births. Stabilization begins at the youngest ages and proceeds upward. Sixty years after the shift, the birth waves have largely disappeared and the proportion under age 15 approximates the stable level implied by the new rates. Those patterns are manifest in the stabilization of both observed and Coale-Demeny model stable populations." (SUMMARY IN FRE)

中文翻译：

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稳定、出生潮和老年人口激增*

这项研究检查了人口在转向一组新的固定生命率后向稳定的过渡。具体来说，作者开发了一个简单的离散人口模型，并使用它来推导出出生轨迹的明确解决方案。“新的生命率与人口的初始年龄构成相互作用并产生出生波，其振幅和衰减取决于最终与初始增长的比率以及稳定净生育的新模式。增长的更大变化和后来的稳定净生育模式产生较大的出生人数波动，从最年轻的年龄开始趋于稳定，然后向上推进。转变60年后，出生潮已经基本消失，15岁以下的比例接近新比率所暗示的稳定水平。