Sample selection in radiocarbon dating

Archaeologists working on the island of O'ahu, Hawai'i, use radiocarbon dating of samples of organic matter found trapped in fish-pond sediments to help them to learn about the chronology of the construction and use of the aquicultural systems created by the Polynesians. At one particular site, Loko Kuwili, 25 organic samples were obtained and funds were available to date an initial nine. However, on calibration to the calendar scale, the radiocarbon determinations provided date estimates that had very large variances. As a result, major issues of chronology remained unresolved and the archaeologists were faced with the prospect of another expensive programme of radiocarbon dating. This paper presents results of research that tackles the problems associated with selecting samples from those which are still available. Building on considerable recent research that utilizes Markov chain Monte Carlo methods to aid archaeologists in their radiocarbon calibration and interpretation, we adopt the standard Bayesian framework of risk functions, which allows us to assess the optimal samples to be sent for dating. Although rather computer intensive, our algorithms are simple to implement within the Bayesian radiocarbon framework that is already in place and produce results that are capable of direct interpretation by the archaeologists. By dating just three more samples from Loko Kuwili the expected variance on the date of greatest interest could be substantially reduced.     

Finite mixture models with concomitant information: assessing diagnostic criteria for diabetes

The World Health Organization (WHO) diagnostic criteria for diabetes mellitus were determined in part by evidence that in some populations the plasma glucose level 2 h after an oral glucose load is a mixture of two distinct distributions. We present a finite mixture model that allows the two component densities to be generalized linear models and the mixture probability to be a logistic regression model. The model allows us to estimate the prevalence of diabetes and sensitivity and specificity of the diagnostic criteria as a function of covariates and to estimate them in the absence of an external standard. Sensitivity is the probability that a test indicates disease conditionally on disease being present. Specificity is the probability that a test indicates no disease conditionally on no disease being present. We obtained maximum likelihood estimates via the EM algorithm and derived the standard errors from the information matrix and by the bootstrap. In the application to data from the diabetes in Egypt project a two-component mixture model fits well and the two components are interpreted as normal and diabetes. The means and variances are similar to results found in other populations. The minimum misclassification cutpoints decrease with age, are lower in urban areas and are higher in rural areas than the 200 mg dl^-1 cutpoint recommended by the WHO. These differences are modest and our results generally support the WHO criterion. Our methods allow the direct inclusion of concomitant data whereas past analyses were based on partitioning the data.     

GENDER, EARNINGS, AND THE ENGLISH SKILL ACQUISITION OF HISPANIC WORKERS IN THE UNITED STATES

Using the 1980 and 1990 Public Use Microdata Samples, we find that labor market outcomes associated with English proficiency vary with respect to gender. For example, a synthetic cohort analysis provides evidence of gender-related differences in Hispanic workers' English skill acquisition. Moreover, we observe that Hispanic women face a lower English deficiency earnings penalty that rises more sharply with education than the penalty obtained by their otherwise similar male peers. Finally, English fluency appears to serve as a stronger occupational sorting mechanism for women than men. ( JEL J3, J1)     

Primary care networks: choose your physicians wisely

As hospitals and health care systems maneuver for a position in the integrated health care delivery system, no initiative is more important than building an effective and competitive primary care network. Yet this critical initiative is fraught with potential pitfalls. In their haste to develop primary care networks, hospitals and health care systems may fail to thoroughly evaluate network participants and in turn create large, inclusive, and inefficient primary care networks that don't come close to breaking even, much less repay practice acquisition costs. In an effort to become more efficient, practitioners often find themselves in the unenviable position of "de-selecting" peers retrospectively. The author presents criteria for evaluating and selecting network physicians.     

The medical practice as business organization

Medical practices historically have not been examined in terms of their organizational structures and of the appropriateness of their structures for survival as business entities. In this paper, we propose a model for the typical medical practice and discuss its fit with current organizational theory. It is apparent that the medical practice organization does not fit with the demands of a rapidly changing and complex environment. To survive and grow, the medical practice organization must align itself with others that have an interest and stake in the health care system, develop teamwork among physicians, bridge the gap between physicians and others in the organization, and recognize that the work done in the organization depends on other components of the organization.     

Practicing managed care in the academic medical center

The purpose of this article is to outline the contrasts between the traditional AMC and an organization oriented toward the delivery of population-based managed care. Academic medical centers differ from one another considerably in the extent to which they serve as quaternary care community resources, the degree to which they emphasize primary care in training and care delivery, and the amount of research undertaken. Nor is there a single organizational structure for managed care; successful managed care is practices in IPAs, multispecialty groups, PHOs, and staff-model HMOs. Nonetheless, the contrasts outlined here between AMCs and managed care organizations (MCOs) are valid in most cases.     

The changing academic health center. The death of the traditional academic physician

Organizational change is required if academic health centers (AHCs) are to survive the decreased societal commitment to them. The changes will generate significant emotional responses in the physicians employed by such institutions. This article presents an analogy between the reactions of academic physicians to the changes they are experiencing, and the stages of grief that Dr. Kübler Ross described in terminally ill patients. By placing physician responses in this context, emotional responses to organizational changes can be more easily understood and managed, allowing academic physicians to devote more energy to facing the threats to AHCs in an innovative and constructive manner.     

International labour migration statistics in Asia: an appraisal

"The present paper attempts a critical review of the data systems of seven major labour-exporting countries--Bangladesh, India, Indonesia, Pakistan, Philippines, Sri Lanka and Thailand--which account for over 90 per cent of labour outflows from Asia....Data...are discussed under separate sections focusing on limitations as well as potential for further exploitation.... For all countries reviewed here, these data significantly understate total labour outflows, and the magnitude of the error seems to vary between countries and reflect both differences relating to the coverage and efficiency of the approval and monitoring procedure. This throws serious doubts on the appropriateness of official outmigration series for cross country comparison. Frequent changes in reporting procedures also make for discrete changes and spurious shifts in data which render trend analysis quite hazardous." (SUMMARY IN FRE AND SPA)     

The implementation of the healthy cities project in developing countries: lessons from Chittagong

The Chittagong Healthy City Project was carried out in late 1994 in Chittagong, Bangladesh. This paper presents findings of an evaluation of the project based upon internationally generated process indicators related to the institutional aspects of the project. The following issues are discussed with regard to project implementation: the institutional organization of local authorities, institutions' conceptual understanding of the project, formal insertion of the project into public authorities' activities, institutional leadership of the project, central-local relations, the lack of interministerial coordination, the project's office, international projects, and community organization. Giving consideration to these issues may help program planners detect problems in forthcoming projects prior to their implementation.