Longitudinal non-euclidean networks: Applying Galileo

This article discusses the theoretical utility of using a non-Euclidean spatial manifold when describing social networks. It proposes that a variant of metric MDS, the Galileo System, can be particularly useful in analyzing social networks and their changes over time, partially because it does not impose Euclidean assumptions on the data. Two sets of longitudinal network data are examined with Galileo. One is the American air traffic network from 1968–1981. The other is ten groups engaged in a computer conference over a 24 month period. In both cases, the results indicate that a Riemannian spatial manifold is required to describe the network structure. Consistent theoretically valid results based upon the non-Euclidean components of spatial manifold are obtained. Further, they could be readily explained by exogenous factors. The implications of these results for network analysis are discussed.     

A bayesian approach to a reliability problem: Theory,analysis and interesting numerics

We consider approximate Bayesian inference about the quantity R = P[Y₂> Y₁] when both the random variables Y₁, Y₂ have expectations that depend on certain explanatory variables. Our interest centers on certain characteristics of the posterior of R under Jeffreys's prior, such as its mean, variance and percentiles. Since the posterior of R is not available in closed form, several approximation procedures are introduced, and their relative performance is assessed using two real datasets.     

Estimation of Potential Health Effects from Acute Exposure to Hydrogen Fluoride Using a "Benchmark Dose" Approach

Communities across the United States are examining the manufacture, use, transport, and storage of hydrogen fluoride (HF) near residential areas as a consequence of a major release of HF in Texas in 1987. Reference exposure levels for routine and accidental HF emissions are calculated using existing animal and human data. The approach employs a logprobit extrapolation of concentration-response data to the 95% lower confidence limit on the toxic concentration producing a "benchmark dose" of 1% response (TC01), called a practical threshold. Species-specific and chemical-specific adjustment factors are applied to develop exposure levels applicable to the general public. Using this method, the 1-hr reference exposure level to protect the public against any irritation from a routine emission (REL-1) is 0.7 ppm and the level to protect against severe irritation from a once-in-a-lifetime (REL-2) release is 2 ppm. This approach is compared to a modified "uncertainty factor" approach.     

Aboriginal Harvesting in the Moose River Basin: A Historical and Contemporary Analysis

Les territoires traditionnels de chasse et de trappe des Cris dans les régions méridionales du bassin de Moose River ont été infiltrés au début du XXe siècle, par les colons euro-canadiens et l'exploitation des ressources qui s'est ensuivie, avec l'encouragement actif du gouvernement provincial. Après la Deuxième Guerre mondiale, ces tendances se sont également propagées au nord du bassin. Selon de nombreux contemporains, l'économie basée sur la chasse et la trappe des Cris s'était désintégrée face à la concurrence des Euro-Canadiens et l'appât du travail rémunéré et de la vie villageoise. Cependant, de récentes études sur le terrain démontrent l'importance continue et la viabilité de l'économie autochtone traditionnelle du bassin de Moose River.
The traditional hunting and trapping territories of the Cree in the southern reaches of the Moose River Basin were infiltrated by Euro-Canadian settlement and resource-based development early in the 20th century, with the active encouragement of the provincial government. After the Second World War, these trends were also evident in the northern part of the Basin. Many contemporaries believed that the Cree hunting and trapping economy had disintegrated in the face of Euro-Canadian competition and the lure of wage labour and village life. However, recent field studies document the continuing importance and viability of the traditional aboriginal economy of the Moose River Basin.     

Rethinking population distribution policies

Developed and developing nations are generally dissatisfied with the spatial distributions of their populations. Dissatisfaction is particularly acute on the part of developing nations which view their problems of population distribution as more serious than those of natural increase. The overwhelming majority of governments have already adopted policies to affect rates and patterns of internal migration or the configuration of their rural and urban populations. However, recent reviews of these policies suggest they have been only partially successful. Apparent policy deficiencies are reviewed and possible remedies suggested in regard to the need for intervention, the scope of policies, their objectives, instruments, and evaluation.     

The consequences of early marriage on marital dissolution

Research has been consistent in documenting the direct negative effect of early marriage on marital stability, while disagreeing over the level of influence of status attainment measures on divorce. However, the discipline has failed to come to consensus on the complexity of these relationships: that early marriage may operate indirectly through mediating variables to increase the likelihood of divorce. The focus of this paper is an analysis of a path model which includes the estimated effects of antecedents of early marriage, early marriage and education on the probability of divorce. Findings using the General Social Surveys support research that suggests that early marriage is the most important variable influencing divorce. Further, little influence of the early marriage measure through education was found.     

Neo-natal mortality in South Asia: The special role of tetanus

First-year mortality in rural Uttar Pradesh is characterized by a predominance (60 per cent) of deaths during the first month of life, of which 66 per cent are reported to be due to tetanus. This pattern is not typical of the historical experience of many developed countries and the current experience of some less developed countries where post-neo-natal mortality predominates. To examine this phenomenon, two causal models of neo-natal mortality (one for tetanus and one for all other diseases) are developed and tested using retrospective survey data from 2000 couples living in rural Uttar Pradesh.

Neo-natal tetanus mortality is found to be primarily a function of opportunities for exposure to the disease (e.g. lack of antiseptic birth practices, ownership of large animals) rather than of socio-economic status or demographic variables. The importance of examining neo-natal mortality by cause, and the shortcomings inherent in making inferences from the historical experiences of Western nations are emphasized.