A Bayesian Analysis of Abundance,Trend, and Population Viability for Harbor Seals in Iliamna Lake,Alaska

Harbor seals in Iliamna Lake, Alaska, are a small, isolated population, and one of only two freshwater populations of harbor seals in the world, yet little is known about their abundance or risk for extinction. Bayesian hierarchical models were used to estimate abundance and trend of this population. Observational models were developed from aerial survey and harvest data, and they included effects for time of year and time of day on survey counts. Underlying models of abundance and trend were based on a Leslie matrix model that used prior information on vital rates from the literature. We developed three scenarios for variability in the priors and used them as part of a sensitivity analysis. The models were fitted using Markov chain Monte Carlo methods. The population production rate implied by the vital rate estimates was about 5% per year, very similar to the average annual harvest rate. After a period of growth in the 1980s, the population appears to be relatively stable at around 400 individuals. A population viability analysis assessing the risk of quasi‐extinction, defined as any reduction to 50 animals or below in the next 100 years, ranged from 1% to 3%, depending on the prior scenario. Although this is moderately low risk, it does not include genetic or catastrophic environmental events, which may have occurred to the population in the past, so our results should be applied cautiously.     

Tribal membership requirements and the demography of ‘old’ and ‘new’ Native Americans

This paper examines the twentieth-century population recovery of Native Americans with reference to urbanization, intermarriage, and differing definitions of the Native American population from census and tribal enrollment data. The recent increase in the Native American population reflected in regular US decennial censuses since 1960 is discussed in terms of changing self-identification of individuals as Native American. Also discussed are criteria for enrollment in Native American tribes, particularly blood quantum requirements. Census enumerations are compared with tribal enrollment data, and it is illustrated that a large proportion of those identifying as Native American in the census are not enrolled in Native American tribes. Special attention is given to how Native American tribal enrollment criteria might impact future population size.     

Same-sex cohabiting elders versus different-sex cohabiting and married elders: Effects of relationship status and sex of partner on economic and health outcomes

In this article, I use pooled data from the 2008–2010 American Community Surveys to examine outcomes for different-sex married, different-sex cohabiting, and same-sex cohabiting elders across several key economic and health indicators, as well as other demographic characteristics. The findings suggest that elders in same-sex cohabiting partnerships differ from those in different-sex marriages and different-sex cohabiting relationships in terms of both financial and health outcomes, and that women in same-sex cohabiting partnerships fare worse than men or women in other couple types. The results indicate that financial implications related to the sex of one’s partner might be more predictive of economic and health outcomes in old age, rather than solely access to legal marriage. Nonetheless, findings suggest that individuals in same-sex cohabiting partnerships might experience worse outcomes in old age as a result of cumulative effects across the life course from both the sex of their partner (in the case of female couples) as well as their lack of access to benefits associated with marriage. Accordingly, these findings demonstrate that persons in same-sex cohabiting partnerships require unique policy considerations to address health and economic concerns in old age.     

Age at First Marriage and Age at Death in the Lincolnshire Fenland, 1252–1478

In five Lincolnshire villages between 1252 and 1478 there is evidence that men and women married fairly late before the Black Death, and that by 1348/9 the Western European marriage pattern of late and prudential marriage was well established. Households were usually nucleated; husbands were on average eight years older than their wives before 1348/9, and five years older after 1348/9. Marriages were short: according to the best calculation shorter before 1348/9 than after, most often terminated by the death of the first husband, and were unlikely to produce more than three children. Since there were more males than females amongst children and young adults, many men remained unmarried, but since the death rate of women was very high, men lived longer.     

Association of educational level and child sex ratio in rural and urban India

Utilizing data from the Census of India, this study compared child sex ratio in rural and urban regions of India and analyzed whether the child sex ratio was associated with mother’s education level. The child sex ratios in the rural and urban regions throughout India were analyzed using the two-sample and paired Student’s t-test. Further, the Chi-square test for trend in binomial proportions was used to assess the association between child sex ratios and mother’s education levels in rural and urban areas. Analysis of the data showed that there was a significant difference between the child sex ratios in rural areas versus urban areas. In addition, the Chi-square test for trend showed that there was a significant association of the child sex ratio and the educational levels of their mothers. This trend occurred in both rural and urban areas.     

知识经济与人口发展

知识经济将是经济发展的主流 ,它要求社会对科技有巨大的投入 ,而这种投入对经济和社会有更大的回馈 ;知识产业将成为经济结构中的主导产业 ;知识经济以知识价值为核心 ;在知识经济时代世界经济将形成全球化的新格局 ,并对传统产业进行技术改造。知识经济时代对人口数量的制约因素将主要是环境的和空间的适度 ;对提高人口素质的要求更为迫切 ;人口的经济结构将发生重要变化 ,知识工人将成为社会的主导力量 ;人口分布与迁移也将出现集中化分散化的新特点。知识经济对人口学研究提出了更高要求 ,人口学研究手段要实现现代化和信息化 ;人口学要开放化     

人口学界对“以人为本”思想的理解和研究

“以人为本”思想起源甚早,国内外许多领域的专家、学者以及实际工作者对这一思想都有过阐述和研究。从我国人口学的视角出发,结合三十多年以来我国计划生育政策的实践与发展,系统地总结了国内人口学界对“以人为本”思想的理解和研究。     

Extended household transitions, race/ethnicity, and early childhood cognitive outcomes

Beyond mothers’ union status transitions, other adults’ transitions into and out of the household contribute to family instability, particularly in early childhood. Using the Early Childhood Longitudinal Study-Birth Cohort (N ≅ 8550), this study examines associations between extended household transitions and age 2 cognitive development. A substantial minority of toddlers experiences these transitions, and their consequences vary by household member type, entry versus exit, and race/ethnicity. Extended household transitions predict lower cognitive scores for white children, but the selection of low-socioeconomic status families into extended households explains these disparities. Grandparent transitions predict significantly higher cognitive scores for African American and Latino children than whites, and some “other adult” transitions predict higher scores for Latinos than African Americans and whites. Extended household transitions’ consequences are independent of co-occurring residential moves and partner transitions. Findings suggest that studying extended household transitions is useful for understanding children’s early development, and their consequences vary by race/ethnicity.     

浅析我国农村育龄妇女流动的人口学价值

本文分析了改革开放以来出现的农村育龄妇女向城市流动的现象,阐述了这种流动对生育观转变、婚姻质量改善和人口经济结构变革产生的积极作用