Laplace-normal mixtures fitted to wind shear data

A mixture model with Laplace and normal components is fitted to wind shear data available in grouped form. A set of equations is presented for iteratively estimating the parameters of the model using an application of the EM algorithm. Twenty-four sets of data are examined with this technique, and the model is found to give a good fit to the data. Some hypotheses about the parameters in the model are discussed in light of the estimates obtained.     

Integrated marked Poisson processes with application to image correlation spectroscopy

Image correlation spectroscopy (ICS) is an experimental technique used in the study of cell tissue, specifically to obtain information about protein aggregates. This paper discusses a filtered Poisson process model of ICS, and uses this to obtain the sampling distribution of an estimator of interest, using spectral methods. Integrals of third- and fourth-order spectra are involved, and methods proposed in the literature are studied numerically. They are found to be infeasible methods, requiring months of computing time. An alternative method is proposed and is illustrated on some actual ICS experiments. A novel feature in this study is the use of a SIMD-class parallel computer, a MasPar MP-2 machine, to obtain some statistical properties of the estimation method.     

Fieldwork in forbidden terrain: the state,privatization and human subjects regulations

In this paper we explore the intersection of the modern-state and fieldwork practices within the social sciences. Our contention is that during the past decade or so there has been an expansion in forbidden or restricted research terrain that threatens the present and future conduct of social research. We argue that this restriction has been engendered by two related developments: privatization and human subjects regulations. The social and political implications of these trends are considered. Her most recent books areMadwives: Schizophrenic Women in the 1950s (Rutgers University Press, 1987) andGender Issues in Field Research (Sage, 1988). He is the author ofCastles of Our Conscience: Social Control and the American State, 1800–1985 (Forthcoming, Polity Press, Cambridge, U.K.)     

The value of green belt land

This paper estimates the value of green belt land by assessing its output: agricultural; amenity; recreational; and savings in costs, by restricting the size of urban areas. These outputs are valued in social terms by the application of welfare economics. Some types of agriculture are shown to impose net social cost rather than benefits. Hedonic price models and contingent valuation are used to assess amenity benefits which are revealed as the most important justification for green belts. These benefits are set against the opportunity cost of the land in terms of foregone housing and industrial development. Uncertainty and irreversibility of a land-use change, from green belt, suggests that the benefits of housing or industry should substantially exceed the value of green belt land before a land-use change is sanctioned.     

Older Workers: Who are the working poor in the U.S.?

With data from the 2000 Health and Retirement Study (HRS), the purpose of this study was to provide a profile of older workers who live poverty, and to compare the demographic, financial, employment, and health attributes of such individuals to similar persons not living in poverty. This study found that 3.5% of employed individuals between the ages of 51 and 61 belonged to the class of working poor. The results of the multivariate logistic regression analyses indicated that the older working poor were more likely to be non-White, less educated, non-married, and had lower levels of net worth than the working non-poor. They were more likely to be employed part time and were less likely to be covered by employee-sponsored health insurance.