Principal curves revisited

A principal curve (Hastie and Stuetzle, 1989) is a smooth curve passing through the middle of a distribution or data cloud, and is a generalization of linear principal components. We give an alternative definition of a principal curve, based on a mixture model. Estimation is carried out through an EM algorithm. Some comparisons are made to the Hastie-Stuetzle definition.     

Clinical program renovation management

The day-to-day management of medical practice is so heavily influenced by tactical imperatives that few physicians have the time to think strategically. Traditionally, the difference between tactics and strategy is not a major concern of most physician executives. The realm of tactics is the short run, when managers must make do with the fixed resources at hand. Strategy addresses the long run, when all resources and markets are variable. A tactical focus is understandable, maybe even acceptable, in industries where nothing challenges traditional approaches to production of an established product or service. However, medical care in the 1990s is changing so fast that a physician executive must devote an incredible amount of time and effort just to stay confused about what is going on.     

"The responsibility to inform, the power to act": a conference for New England college newspaper editors on the role of the campus press in addressing substance use issues.

College newspapers are a powerful but underutilized medium for educating students on health issues, including those related to drug and alcohol use on campus. Editors of these publications are in a position to wield significant influence among their readers. In addition to communicating factual information about the prevalence and impact of substance use among college students, editors can use the press to advocate changes in students' attitudes and behaviors and in college or community policies that affect substance use. A pilot conference was held to help New England college newspaper editors perceive the importance of their role in educating their peers about substance use and other health-related issues, and to offer concrete suggestions as to how they can incorporate these topics into an "activist" campus press.     

Secularization and the politics of traditionalism: The case of the right-to-life movement

Research on the traditionalist movement against abortion needs alignment with currents in historical sociology, the theory of social movements and the sociology of politics. The religious (specifically, Christian) basis of the right-to-life movement has attracted considerable attention in the literature. The movement is seen as a traditionalist bloc claiming to oppose secularization and return to customary restrictions. However the tradition in question appears to be a recent social construction. There is slim warrant in the actual traditions of Western religion for asserting a categorical right to life. As a result, the movement's ideology is best approached as the product of—rather than the antidote to—secularizing processes (including the demographic transition, discourse about rights, markets for symbolic entrepreneurs and the separation of church and state) and possibly as an unintended import from non-Western religion. Implications for traditionalism, the functions of religion, and the study of countermovements are explored. This case illustrates the value of attending to historical sequences and the external cultural environments of social movements.     

Stochastic modelling of regional annual rainfall anomalies in East Africa

ARIMA (p, d, q) models were fitted to areal annual rainfall of two homogeneous regions in East Africa with rainfall records extending between the period 1922–80. The areal estimates of the regional rainfall were derived from the time series of the first eigenvector, which was significantly dominant at each of the two regions. The first eigenvector accounted for about 80% of the total rainfall variance in each region.

The class of ARIMA (p, d, q) models which best fitted the areal indices of relative wetness/dryness were the A R M A (3, 1) models. Tests of forecasting skill however indicated low skill in the forecasts given by these models. In all cases the models accounted for less than 50% of the total variance.

Spectral analysis of the indices time series indicated dominant quasi-periodic fluctuations around 2.2–2.8 years, 3–3.7 years, 5–6 years and 10–13 years. These spectral bands however accounted for very low proportion of the total rainfall variance.     

Marriage and its transition in Bangladesh

The author examines developments in marriage patterns in Bangladesh in light of social, cultural, and economic conditions. Previous literature on the subject is used to discuss Muslim marriage, Hindu marriage, child marriage, mate selection and social mobility, and the question of a marriage squeeze. "The analysis presents evidence that the society is experiencing a change in its family formation, mating process and family type. This transition is to some extent towards the characteristics of [the] Western World, but in a poor economy. Part of this transition is due to the effect of modernization and part due to increasing poverty."