Persistence of females that produce only female progeny in lepidoptera

Summary In Lepidoptera females that produce only female progeny, can be found in wild populations of at least 11 species. The genetic variation is passed on to each generation of female offspring. If genetically abnormal females produce more female offspring than normal females do and mating is random, then populations containing these abnormal females will have a biased population sex ratio. Unmated females will increase due to the scarcity of males and so the population as a unit will die out. Several possible biological explanations for the persistence of the genetic variation have been proposed. But experiments and observations have not verified those hypotheses. Simulations of Heuch's model (1978), however, have shown that the variation persists if the population is distributed, in patches and there is dispersal among patches, even when insects disperse at random. Abnormal females tend to persist at both low and high migration rates, but the probability of persistence is higher at high migration rates. It has been suggested that abnormal females in a population are an adaptation, but the results of this investigation show that this explanation, may not be plausible.     

我国人口与经济增长稳定关系的实证分析（1953-2000）

改革开放前,我国人口数量和人口密度的增加推动了经济增长,人口与经济增长具有长期稳定关系;改革开放后,大部分地区的人口逐渐趋向于成为经济增长中的一个外生变量。在1953-2000年间,我国经济发展相对落后地区(以西藏为代表)的人口与经济增长存在长期稳定关系,人口数量和人口密度的增加对经济增长有正的效应。总体来看,在我国经济发展的较低阶段,人口与经济增长一般存在长期稳定关系,但当经济发展到较高阶段时,人口与经济增长可能不存在稳定关系。     

河南农村留守妇女状况调查研究

本文利用我们在河南农村的调查数据对留守妇女的状况进行了研究。结果表明,人口流动改变了农村留守妇女的家庭地位。由于丈夫的外出,留守妻子承担了更多的家庭责任和义务,还要想办法对付各种困难。     

New midyear age-sex-color-specific estimates of the U.S. population for the 1940s and 1950s: including a revision of coverage estimates for the 1940 and 1950 censuses

This paper describes new midyear (July 1) estimates of the "true" population of the United States by age, sex, and color (white, nonwhite) for the 1940s and 1950s. It also presents the corresponding implied coverage estimates for the 1940 and 1950 censuses. The new population estimates are calculated by combining the most recent figures on the 1960 population with estimates of the demographic components of change for the 1950s and 1940s in an iterative reverse cohort-component projection algorithm. Among the principal findings of the new estimates are: (a) existing midyear estimates of the "true" population in the 1950s are 450,000 to 500,000 too high; (b) existing age-specific estimates for the 1950s tend to underestimate the population at the older ages (55 years and over) and overestimate the population in the young and middle adult years (15 to 54 years); (c) estimates of the "true" population in the 1940s were too low except for nonwhites at ages 65 and over; (d) existing estimates of percentage net undercount and underenumeration for the 1950 and 1940 censuses tend to be too high, substantially so for nonwhites in the 1940 Census; and (e) nonwhites were more completely enumerated in 1940 than in 1950. Thus, in addition to being methodologically and temporally consistent with post-1960 estimates, the new population estimates described here imply some substantial revisions in demographic, social, and economic statistics for the two decades prior to 1960.     

Measuring and Analysing the Wellbeing of Australia’s Indigenous Population

According to most standard socioeconomic indicators (for example employment, income and education), Indigenous Australians tend to have worse outcomes than their non-Indigenous counterparts. Most objective health indicators including life expectancy also tend to be worse. Traditionally, these two domains and associated objective indicators have been the focus of research, government policy and evaluation. There has been less research, however, on differences between Indigenous and non-Indigenous Australians in subjective measures of wellbeing. In this paper, I attempt to answer three related research questions on Indigenous wellbeing—What is the average level of emotional wellbeing and satisfaction with life for the Indigenous and non-Indigenous population of Australia? How do the differences between the two populations change once other characteristics have been controlled for? What are the factors associated with emotional wellbeing within the Indigenous population? With regards to the first two questions, Indigenous Australians are less likely to report frequent periods of happiness and more likely to report periods of extreme sadness than the non-Indigenous population. Surprisingly, given these results for emotional wellbeing, a major finding from the analysis was that Indigenous Australians were significantly more likely to report above-average satisfaction with their life. The main finding with regards to the third question is that using retrospective measures, those in remote areas report higher levels of happiness than those in non-remote areas. This is different to the results for socioeconomic status and objective measures of health found elsewhere and has important implications for government policy in Australia.     

Impacts per unit weight in catch by two types of fisheries on a chub mackerel population

By using data on the age-specific annual fecundity and catches-at-age by each fishery in a chub mackerel (Scomber japonicus) population in the Pacific Ocean off Japan during 1970 to 1992, we evaluated the long-term fluctuation in impacts of two types of fisheries on the chub mackerel population. The purse-seine fishery consistently had a larger impact on the population than did the dip-net fishery, mainly because the catch by the former was much larger than that by the latter. To evaluate impact per unit weight in catch, we calculated the average reproductive value per unit weight over individuals caught by each fishery as an indicator of efficient use of bioresource. Because the proportion of immature fish caught by the purse-seine fishery was usually larger than that by the dip-net fishery, the impact per unit weight in catch by the purse-seine fishery was not always less than that by the dip-net fishery.     

广东退休人口的规模与结构特征分析

本文对劳动统计资料和人口普查资料的分析表明,广东退休人口总量持续快速增长,老年人口中退休人口比例提高。退休人口趋于向城市和珠江三角洲集聚。性别结构逐步向平衡方向变化,较高年龄的退休人口增多。退休人口在保持国有身份特征时趋向多样性。退休人口整体教育素质改善,流动退休人口具有一定的人力资源优势。     

老年抚养比：理论与实际的偏离

理论老年抚养比与实际老年抚养比存在严重偏离 ,老年人口劳动参与率及劳动年龄人口劳动参与率是影响老年抚养比偏离的主要因素 ,老年抚养比在社会经济中发挥的重要作用 ,决定了我们应当对老年抚养比偏离必须有一清晰认识 ,扭转长期以来用理论老年抚养比代替实际老年抚养比分析相关问题的习惯作法 ,走出多年来以理论老年抚养比代替实际老年抚养比的误区 ,更加科学、准确地分析和判断人口发展对社会经济发展的影响。     

1990-2010年广州青年人口增长及其社会构成变动

本文采用人口普查数据分析了1990-2010年广州青年人口数量增长与受教育程度、婚姻状况和职业构成变动特征.广州青年人口绝对规模扩大、增速下降和相对规模收缩.人口迁移流动是青年人口增长变化的最主要因素.青年人口的受教育程度构成由中低层次向中高层次转变,未婚为主、已婚有配偶居次的婚姻构成更趋向未婚状况,职业以体力劳动者为主、正逐步向高级化转变.这些社会构成存在性别和年龄差异.     

浅析上海市近年来对外来流动人口的政策变迁

本文主要是对上海市近年来对外来流动人口政策变迁的综述和浅析。根据文化程度的高低 ,一般将流动人口分为两个不同的层次 ,也相应出台了不同的政策 ,从针对层次较高的所谓“引进人才”的蓝印户口、工作证制度、以及居住证到针对层次较低的外来普通务工人员的就业证制度和综合保险政策。最后得出的结论是 :根据上海经济、社会发展变化的相应需求 ,“筑高门槛 ,开大城门” ,成为上海市对外来流动人口管理政策的基本趋势 ,外地人进入上海的难度在增加。     

Estimating historic population data for small geographies using census housing information

Historical population data for small geographies (e.g. blocks, block-groups, and census tracts) are not available for periods earlier than 1980. In this research note, we propose a geographically-constrained housing unit method (GHUM) to estimate historic population for small geographies using housing age data available in the 1980–2000 censuses. The GHUM is a two-stage method. The first stage follows a traditional housing unit method and provides initial household and group quarter population estimates for small geographies. The second stage takes advantage of the availability of historic data for larger geographies (e.g. counties, states) to adjust the first stage estimates and to provide final estimates. The GHUM is used to estimate 1940–1990 county population and census tract population in Kentucky. The quality of the population estimates is assessed. A two-sample Kolmogorov–Smirnov test indicates that these estimates are statistically reliable at the 10 % significance level.     

On Stable Population Theory With Immigration

The paper extends stable population theory to include a constant stream of immigration. Previous attempts at tackling the problem have either restricted themselves to a below-replacement native population or else used an approach that does not produce the values of all of the parameters explicitly. It is shown that under a constant stream of immigration, the population will asymptotically tend toward a constant, linear, or exponential behavior, depending on whether the fertility behavior is below, equal to, or above replacement level. All of the parameters are determined in terms of the characteristics of the population at the origin.     

云南流动人口与艾滋病扩散

人口流动既是社会经济进步的标志之一 ,也会带来一系列的社会问题。由于流动人口具有与常住人口不同的特征 ,在迁移过程中 ,他们不仅成为艾滋病的易感人群 ,同时也成为艾滋病扩散的重要媒介。这一点 ,可以从流动人口分布、流量与HIV/AIDS流行程度的时、空关系中得到清楚的印证     

基于ESDA的上海少数民族常住人口空间分析

利用2012年上海少数民族常住人口分布数据,采用数理统计和ESDA技术对上海少数民族常住人口数量、分布状况进行研究.研究表明：上海少数民族常住人口数量不断增加且集中分布于中心城边缘区和近郊区;少数民族常住人口在空间格局上存在显著的“同质集聚、异质隔离”;显著的“冷点”区域主要集中在崇明县、金山区等远郊区,显著的“热点”区域主要集中在五角场区域和九亭镇,较为热点的区域主要集中于花木镇、七宝街道、江川路街道、车墩镇和新桥镇等区域,而青浦区、浦东新区大部分区域则是较为冷点区域,中心城区大部分区域形成了随机分布的区域;不同族别的少数民族分布状况有着较大差异,亲缘、地缘和族缘为纽带的乡土观念仍然是少数民族常住人口集聚的重要因素.     

上海市人户分离状况的空间特征分析——基于“六普”数据

＂六普＂数据显示,近几年上海市人户分离状况呈现出新的空间特征,主要表现在：人户分离人口的规模和迁移率在空间分布上呈现出严重的不均衡;大部分区县人户分离人口的来源地及迁居目的地集中化程度高,具有＂近邻优先＂的特点;逐步形成由中心城区县流向近郊区区县和中心城区县之间相互流动的两大迁移圈;中心城核心区、边缘区、近郊区、远郊区等四大区域之间的人户分离人口流动呈现出三大迁居主流。本文在总结这些空间特征的同时,就如何解决上海市人户分离问题提出了几点建议,以期上海市内户籍人口的迁移能科学健康有序进行。     

Changing vital rates and age distributions

Abstract In a time of rapid change in birth and death rates demographers need to know the consequences of such changes for age distribution. Does the fall in death rates tend to make the age distribution older? It certainly enables individuals to grow older, but for population aggregates the effect depends on the ages at which mortality improves. Coale, Stolnitz, Schwarz, Lorimer, the United Nations and other writers have investigated trends in age-specific birth and death rates. In particular they have demonstrated that the falling mortality which is now nearly universal does not generally make the population older and sometimes makes it younger. The present article contributes a technique for further examination of this phenomenon.     

Health-related disabilities and matching of spouses: Analysis of Swedish population data

Recent research concerning the incidence of reported work-limiting disabilities in the married population indicates a degree of interdependence between spouses' disabilities. This pattern is consistent with several hypotheses. Spouses tend to share many lifestyle traits that might lead to common health outcomes. Alternatively, their joint reports might reflect a shared preference for income benefits or workplace accommodations available to disabled individuals. Another possibility is that disabled individuals tend to be matched in the process of marital formation. This paper investigates the latter hypothesis. Taking advantage of a unique data set from the Swedish population, we select a sample of recently married couples and trace them back in time to their single years. Our analysis indicates nonrandom matching on the basis of disability status. After controlling for observed traits such as age and education, we find a residual correlation between future spouses that is positive and strongly significant. The magnitude of the correlation is within the range of residual correlations obtained from other studies that address marital matching in the contexts of education and earnings. The authors wish to thank anonymous referees and the editors of this journal for helpful comments and prompt reviews. Responsible editor: Christian Dustmann.     

Aging population scenarios: an Australian experience

During the past decade, there has been wide public discussion about the effects of population and immigration policies. There is some consensus that an older population imposes economic costs but uncontrolled population growth imposes congestion and environmental burdens. While many realize that policies which restrict population tend to exacerbate aging, the inevitable trade-off is not widely acknowledged. Fewer still appreciate that there is a sustainable age distribution that is largely imposed on us by nature that cannot be defeated in the long term. In this paper, we look at the ‘aging issue’ for Australia by looking at the total population and age distribution as a joint outcome. For ease of interpretation, the age distribution is converted into a required retirement age (RRA) to maintain dependency ratios at 2010 levels. We examine the effects of alternative policy scenarios on total population and RRAs, benchmarked against a hypothetical population in zero population growth equilibrium. We account for differing demographic groups of immigrants and emigrants as well as trends in mortality. Policy scenarios can be well summarized by plotting the trajectory of the two outcomes, total population and RRA, with the equilibrium values as axes.     

广东省外来人口的定居性与流动性初步分析

根据人口普查资料,文章分析了广东省外来人口在居住地的时间分布情况,描述了不同人口属性和不同社会、经济特征的外来人口在居住时间上的差别,并且描述了在居住地出生"外来人口"的一些特征,最后利用Logistic回归对影响外来人口居住时间长短的多种因素做综合分析。在描述分析的基础上,论文最后指出,必须正视大量的外来人口实际上已经转变为长期定居人口的事实,并解决其产生的相关社会问题。     

Completing the fertility transition in the developing world: The role of educational differences and fertility preferences

This study summarizes patterns of educational differentials in wanted and unwanted fertility at different stages of the fertility transition. The data are from Demographic and Health Surveys in 57 less developed countries. As the transition proceeds, educational differentials in wanted fertility tend to decline and differentials in unwanted fertility tend to rise. An assessment of fertility patterns in developed and less developed countries with low fertility concludes that these differentials are likely to remain substantial when less developed countries reach the end of their transitions. This conclusion implies that the educational composition of the population remains a key predictor of overall fertility in late transitional countries and that low levels of schooling can be a cause of stalling fertility.