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.     

《蓝调石墙T》中跨性别主体的性别表达

本文结合小说中主人公洁斯的成长历程,分析了洁斯性别表达过程中的存在及其困境,认为:孩童时期洁斯的选择恰好说明了性别是早已存在且流动的;洁斯选择成T后,"她"的选择正好等同于自我表达;洁斯进了男人们的疆域工作,性别表达受制于跨性别主体的经济地位;困于男人外表下的洁斯性别表达时面临了悖论式的困境:自我身份的危机;最终,洁斯找回本质自我,并以此坚持自我的性别表达。     

An evaluation of school district guidance and counseling programs: Procedures and results

This evaluation examines the administrative history, staffing levels, and content of school district guidance and counseling activities. Case studies were made in a 50% random sample of a district's 45 elementary schools. Eight hundred teachers, parents, and students were interviewed. All school plans were reviewed. Five-year staffing patterns and staff changes were studied. All district staff with guidance and counseling responsibilities recorded characteristics of guidance and counseling contacts for 15 days. Schools with and without counselors were studied to estimate differences in who receives services and what is provided. Results show systematic differences in the level and kind of services provided secondary and elementary students. Approximately one-third of the schools studied had stable programs. Schools with stable programs provided a broader range of services and distributed them in a more equitable manner.     

人口预测常用模型及其比较分析

人口问题一直是制约我国经济快速发展的关键因素之一，准确预报人口增长是人口研究的一个热点．本文根据（2005年中国统计年签》公布的人口数据分别建立了CM（1，1）模型、Leslie模型、Logistic模型来预测我国未来人口发展的趋势，并比较了这几个模型预测的优缺点．     

人口预测的随机方法:基于Leslie矩阵和ARMA模型

本文探讨了人口预测的一种随机方法。文章回顾了经典的Leslie矩阵并结合中国的人口统计数据,用时间序列的ARMA模型对未来的生育率、死亡率进行估计,并由此构造Les-lie矩阵,经时间序列的数据中心化,根据自相关函数、偏自相关函数的截尾性或拖尾性,以及贝叶斯信息准则函数方法对模型定阶,实现对ARMA模型的识别。在中国人口预测方面的应用证明,基于Leslie矩阵和ARMA模型的人口随机预测方法是稳健的,具有很强的适用性。由于统计数据可获得性的局限,对模型做了不少假设和近似。随着人口数据的积累,未来将会在此方面有所改进。     

Relation of transition probabilities in the Leslie model to those from experimental cumulative distributions

Summary We explore the relationship between transition probabilities in the Leslie model and those derived from experimental cumulative distributions. The nature of the two kinds of probabilities are discussed, and a formula derived for converting from one to the other. A numerical example is given to illustrate the differences.     

On the intrinsic force of convergence to stability∗

Observed populations differ greatly in the speed with which they approach the stable form, but what determines rates of convergence is not fully understood. The present paper shows that the force of convergence does not approach a fixed value, but oscillates indefinitely around an “intrinsic”; level. That level, h?, is determined by the square of the ratio of the 2 largest eigenvalues of the Leslie matrix. The value of h? can be closely approximated by a simple function that changes directly with the square of the coefficient of variation and inversely with the mean of the stable net maternity function. Population entropy, another measure of dispersion relative to the mean, is also highly correlated with h?.     

How responsive is U.S. population growth to immigration? A situational sensitivity analysis

There has been public concern about the effect of immigration on population growth in the U.S. But how responsive is population growth to immigration? This paper examines the sensitivity of intrinsic population growth to immigration and situates such sensitivity in fertility and survival changes. The application of second derivatives on a modified Leslie matrix facilitates the analysis of situational sensitivity of U.S. population growth to immigration. The results show that the sensitivity to immigration is not as influential as the sensitivity to fertility, and that the sensitivity to immigration further depends on changes in fertility and survival.     

Populations with constant immigration

We consider a Leslie‐type model of a one‐sex (female) population of natives with constant immigration. The fertility and mortality schedule of the natives may be below or above replacement level. Immigrants retain their fertility and mortality, their children adopt the fertility and mortality of the natives. It is shown how this model may be written in a homogeneous form (without additive term) with a Leslie‐type matrix. Reproductive values of individuals in each age group are discussed in terms of a left eigenvector of this matrix. The homogeneous form of our projection model permits the transformation into a Markov chain with transient and recurrent states. The Markov chain is the basis for the definition of genealogies, which incorporate immigration. It is shown that genealogies describe the life histories of individuals in a population with immigration. We calculate absorption times of the Markov chain and relate them to genealogies. This extends the theory originally designed for closed populations to populations with immigratioa     

Transnational Capitalist Class in the Global Financial Crisis: A Discussion with Leslie Sklair

In an interview, Leslie Sklair, author of The Transnational Capitalist Class (2001) and Professor Emeritus in Sociology at the London School of Economics, discusses his thoughts on today's global financial crisis, its connections to a globally dominant social class—the transnational capitalist class—as well as his views on the US invasion and occupation of Iraq, and clarifications on his theoretical approach.

En una entrevista, Leslie Sklair, autor de La clase capitalista trasnacional (2001) y profesor emérito en sociología de la Facultad de Economía de Londres, discute tanto sus pensamientos sobre la crisis financiera global actual, y sus conexiones con una clase social global dominante—la clase capitalista trasnacional—como sobre su punto de vista sobre la invasión y ocupación de Iraq por los E.E.U.U., y las aclaraciones sobre su enfoque teórico.