Pre‐procreative ages in population stability and cyclicity

Age‐specific models of population renewal (with and without feedback) which imply convergence to a stable state for some levels of fertility or feedback may imply the presence of long‐term cycling around a constant or exponentially changing equilibrium for other levels of fertility or feedback. The switch from one regime to the other is a “bifurcation.”; The conditions for bifurcation involve the roots of an analogue of Lotka's Equation.

Typically bifurcation is induced by raising the strength of feedback or the level of fertility. It has been known since the early 1980s, however, that this is sometimes impossible. It is sometimes impossible even with the linear renewal equation itself and with the most basic of non‐linear models, Lee's cohort feedback model.

Here it is proved that this typical route to bifurcation does not fail for these basic models in the presence of a condition which always holds for realistic applications with higher organisms: the existence of a span of ages before the onset of fertility.

Specifically, a strictly positive lower bound on ages of procreation is proved to be sufficient to guarantee the existence of a rescaling of Lotka's Equation for which the real part of some complex root vanishes. This result holds for absolutely Lebesgue‐integrable (signed) net maternity functions on the positive real line and for absolutely summable (signed) net maternities on the positive integers.

It follows that Coale's rescaling device for the analysis of approach to stability in stable population theory can be implemented for all realistic human net maternity schedules. It also follows that the many special cases of the cohort feedback model throughout population biology will all generate persistent cycling instead of stability if feedback is sufficiently strong.     

城市人口密度、国内市场规模与就业增长

我国经济“高增长、低就业”现象的原因在于我国贸易成本过高，国内市场规模较少。解决我国就业问题的关键在于减少行政干预，顺应市场要求，促进人口在空间上的适度集中，提高人口密度，提高消费效率，扩大市场规模。应进一步完善城乡一体的户籍制度，完善整合城乡劳动力市场，提高要素流动能力等。     

西部人口与可持续发展

可持续发展要求有良好的人口环境。人口是西部可持续发展的首要问题。在西部发展中 ,制定积极的人口政策 ,控制人口、提高人口素质 ,为西部可持续发展创造良好的人口环境     

西夏开国人口考论

本文在认真研读相关文献的基础上 ,对西夏开国人口作了较为深入细致的考察和论述 ,认为由于史料采信等原因 ,以往研究与历史事实多有出入 ,存在不少问题。文章进而指出 ,特定的历史与地理条件决定了西夏自建国伊始即是一个“土地有限 ,人民有数”的地方性民族割据政权 ,其开国兵力不过 30余万 ,人口总数则仅及百万     

人口较少民族文化艺术遗产的新开发现象

我国 2 2个人口在 10万以下的少数民族主要生活在西部地区。近年来 ,他们在对待文化艺术遗产方面出现了一些新的特征 :歌手们更加关注自己民族的歌曲 ;地方政府在城镇和旅游建设中强调突出民族特色 ;农牧民组织民族服装模特队等。在此把这种发展变化称为“新开发”现象。     

青海同仁浪加村人口、婚姻与家庭调查

本文在田野调查的基础上,对青海同仁浪加村的人口、婚姻与家庭状况进行分析,总结了浪加村的人口年龄结构类型及婚姻与家庭的特征。     

社会工作视野下的城市少数民族流动人口问题

城市少数民族流动人口问题正逐渐成为社会关注的一大热点,文章主要对城市少数民族流动人口的现状、特点,对城市发挥的积极功能和城市少数民族流动人口问题的具体表现作一概述,并从社会工作这一新的视角分析了城市少数民族流动人口问题的成因,在此基础上就社会工作如何介入此问题提出一些建议.     

浅析中国土族人口分布格局及其社会发展

人口分布格局,既是人在空间分布上呈现出来的地理状态,又是许多附着于分布环境上的社会人文变量的外在表现,因此对其进行研究具有探索自然和认识社会的双重意义。本文就中国土族人口的分布格局进行探讨,从历史和现实两方面分析了形成这种分布的原因,并在此基础上探讨了与人口分布格局密切相关的人口城市化、人口流动、人口素质提高、区域经济发展等社会热点问题,以期为政府政策的制定提供可靠的依据。     

Consistent Probabilistic Social Choice

Two fundamental axioms in social choice theory are consistency with respect to a variable electorate and consistency with respect to components of similar alternatives. In the context of traditional non‐probabilistic social choice, these axioms are incompatible with each other. We show that in the context of probabilistic social choice, these axioms uniquely characterize a function proposed by Fishburn (1984). Fishburn's function returns so‐called maximal lotteries, that is, lotteries that correspond to optimal mixed strategies in the symmetric zero‐sum game induced by the pairwise majority margins. Maximal lotteries are guaranteed to exist due to von Neumann's Minimax Theorem, are almost always unique, and can be efficiently computed using linear programming.     

Nonparametric Estimation of the Number of Drug Users in Hong Kong Using Repeated Multiple Lists

We update a previous approach to the estimation of the size of an open population when there are multiple lists at each time point. Our motivation is 35 years of longitudinal data on the detection of drug users by the Central Registry of Drug Abuse in Hong Kong. We develop a two‐stage smoothing spline approach. This gives a flexible and easily implemented alternative to the previous method which was based on kernel smoothing. The new method retains the property of reducing the variability of the individual estimates at each time point. We evaluate the new method by means of a simulation study that includes an examination of the effects of variable selection. The new method is then applied to data collected by the Central Registry of Drug Abuse. The parameter estimates obtained are compared with the well known Jolly–Seber estimates based on single capture methods.