Application of Markov chain Monte Carlo methods to modelling birth prevalence of Down syndrome

Data collected before the routine application of prenatal screening are of unique value in estimating the natural live-birth prevalence of Down syndrome. However, much of these data are from births from over 20 years ago and they are of uncertain quality. In particular, they are subject to varying degrees of underascertainment. Published approaches have used ad hoc corrections to deal with this problem or have been restricted to data sets in which ascertainment is assumed to be complete. In this paper we adopt a Bayesian approach to modelling ascertainment and live-birth prevalence. We consider three prior specifications concerning ascertainment and compare predicted maternal-age-specific prevalence under these three different prior specifications. The computations are carried out by using Markov chain Monte Carlo methods in which model parameters and missing data are sampled.     

A case study of the labour market status of recent mainland Chinese immigrants,metropolitan Toronto

"This article focuses on an analysis of the labour market status of recent MCIs [mainland Chinese immigrants to Canada], taking into account such factors as gender, educational attainment, language proficiency and period of arrival (or length of residence in Canada), and uses Metropolitan Toronto as a case study. The effect of each factor on MCIs' labour market status will be analysed separately, followed by two logit models examining the simultaneous effects of the factors and their relative importance." (SUMMARY IN FRE AND SPA)     

IDENTITY POLITICS, PARTISANSHIP, AND VOTING FOR WOMEN CANDIDATES

In 1992 a record 14 women sought statewide office by running"as women" and as representatives of women. In this articlewe examine whether their appeals led to widespread vot ing onthe basis of gender identity. We find evidence that the sexof the voter is significantly related to voting for female candidatesin eight of 13 states, and among partisans of both parties aswell as Independents. Further, we find that these effects areamplified by Democratic female candidates who are rated as mostfeminist, and that this is especially the case for those withno partisan attachments.     

Population growth and the changing ecosystem in Mindanao

Mindanao is the second largest island in the Philippines. Once considered the greenest spot on earth, it has since been highly exploited. This paper discusses the changing ecosystem of the island as a result of rapid population growth since the early 1900s. Not much is known about Mindanao before 1900. From 1913, however, population grew on Mindanao as the American colonial government established agricultural colonies to open up the south for trade and development. Colonial settlement together with migration and natural population increase led to environmental resource degradation and the displacement of indigenous communities such as the Moros and Lumads. Legal and illegal logging and rampant kaingin agriculture have also stressed the environment. The opening of the Mindanao frontier, Philippine development, the Great Migration, incursion of the Mindanao upland, deforestation, the displacement of indigenous communities, and the possible maintenance and rehabilitation of the ecosystem are discussed.     

Acing the 'chemistry' test

With the right boss, you can go far and learn much. The wrong boss could actually slow or even stall your executive career. When you interview for a job, you're also interviewing for a boss--and it's in your own interest to try to find the individual who is the best possible fit with your own management style. This is a matching process--not quite a courtship, but with some of the same characteristics. What can you do to ensure a good match with your new boss? (1) Do your homework; (2) Make your interview a dialog; (3) Use subtle strategies, too, such as watching for body language; (4) Ask the employer for references; and (5) Know yourself.     

Modeling household fertility decisions with generalized Poisson regression

This paper models household fertility decisions by using a generalized Poisson regression model. Since the fertility data used in the paper exhibit under-dispersion, the generalized Poisson regression model has statistical advantages over both standard Poisson and negative binomial regression models, and is suitable for analysis of count data that exhibit either over-dispersion or under-dispersion. The model is estimated by the method of maximum likelihood. Approximate tests for the dispersion and goodness-of-fit measures for comparing alternative models are discussed. Based on observations from the Panel Study of Income Dynamics of 1989 interviewing year, the empirical results support the fertility hypothesis of Becker and Lewis (1973). Received January 7, 1997 /Accepted April 3, 1997     

Ability, disability, and the oldest old

A measure of range of ability is used to profile the 85-years-old-and-older (oldest old) population, including the highly disabled institutional population. This new measure uses two new questions available in the 1990 Decennial Census concerning a self-care limitation and a mobility limitation as well as the usual question concerning a work limitation. In addition to examining the extent of disability among the oldest old, the article examines the extent of care potentially available in the household as well as the economic characteristics of this age group. It is also profiled in terms of relevant personal characteristics, including age, gender, marital status, race, ethnicity, rural residence, education, and employment. A key question addressed is the need for help or care among the oldest old and how various long-term care proposals would meet such needs. A careful analysis of this unique and growing population is necessary to both allay fears of the cost of care or help as well as to dispel stereotypes of this age group as frail and dependent, and in need of institutional care.