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.     

A non-parametric index of tracking

SUMMARY A two-sample version of the non-parametric index of tracking for longitudinal data introduced by Foulkes and Davis is described. The index is based on a multivariate U -statistic, and provides a measure of the stochastic ordering of the underlying growth curves of the samples. The utility of the U -statistic approach is explored with two applications related to growth curves and repeated measures analyses.     

Curved Chaotic Map Time Series Models and Their Stochastic Reversals

This paper considers two types of chaotic map time series models, including the well-known tent, logistic and binary-shift maps as special cases; these are called curved tent and curved binary families. Deterministic behaviour is investigated by invariant distributions, Lyapunov exponents, and by serial dependency. Stochastic time reversal of the families is shown to produce models which have a broader range of stochastic and chaotic properties than their deterministic counterparts. The marginal distributions may have concentrations and restricted supports and are shown to be a non-standard class of invariant distribution. Dependenc y is generally weaker with the reversed stochastic models. The work gives a broad statistical account of deterministic and stochastically reversed map models, such as are emerging in random number generation, communica tion systems and cryptography     

Statistical Methods and Graphical Displays for Analyzing How the Association Between Two Qualitative Variables Differs Among Countries, Among Groups, Or Over Time: A Modified Regression-Type Approach

Many interesting sociological questions pertain to how the association between two variables depends on a third variable. In sociological applications, the third variable often pertains to countries, to subgroups of a population, or to time periods. We propose a regression-type approach that specifies that the log-odds- ratios that describe the two-way association of interest are a linear function of latent scores for the third variable. Additive and multiplicative models currently in use by researchers are special cases of the regression-type model. To illustrate the utility of the regression-type approach, we apply this approach to analyze (1) data on occupational mobility in the United States, Britain, and Japan (comparing mobility in these countries) and (2) data on the association between religion and voting behavior in U.S. presidential elections from 1968 to 1992 (comparing this association in the different elections). We also introduce here graphical displays that can be used to obtain worthwhile information about goodness-of-fit and to aid in substantive interpretation.     

Severely Traumatized Siblings: A Treatment Strategy

Siblings who have suffered severe trauma and disrupted attachment relate to one another in ways that interfere with individual development, the chance to benefit from connections with adults, the establishment of healthy sibling relationships, and the working through of traumatic experiences. The authors use case examples to illustrate four distinct sibling patterns: absent, adult lockout, half and half, and trauma shield. The authors highlight the importance of recognizing these types and then varying the therapist's treatment stance to pursue five goals. These include suspending problematic sibling relationships to create room for bonding with caring adults, transferring attachment behaviors and impulses to a receptive adult, resuming healthy individual development, forming more adaptive sibling connections, and expressing shared traumatic content.     

ELASTIC CAPITAL SUPPLY AND THE EFFECTS OF FISCAL POLICY

Existing analyses of the effects of fiscal policy in general equilibrium models have typically been conducted under the assumption that the long-run supply of capital is perfectly elastic at a fixed rate of time preference. These analyses have shown that the long-run response of the capital stock to changes in fiscal policy is crucial to generating the potential for “multiplier” effects in these models. In this paper we ask, what are the implications of relaxing the assumption of perfectly elastic capital supply for the analysis of fiscal policy? We show that with less than perfectly elastic capital supply, the potential for multipliers is actually enhanced. (JEL E62, D90)     

Media Technologies, Images of Drugs, and an Evocative Telepresence

I regard electronic media technologies as framing devices for how viewers perceive issues associated with illegal drugs. Controllers of electronic media technologies produce and disseminate images of illegal drugs and users of such drugs to which viewers respond. People who control the images of electronic media production create an evocative telepresence, or a visual context that relies on appeals to authority and emotion. However, viewers do not merely respond to images of illegal drugs; rather, they actively interpret such images and draw their own conclusions. To demonstrate the complex relationship between electronic stimuli and viewer responses, I report on a classroom experiment comparing those who saw and heard a heroin user with those who only heard this user. I also report findings from student perceptions of and reactions to four drug films. Results of the experiment and the readings of films indicate that viewers, especially those who can see and hear electronic displays, are sophisticated consumers who respond to immediate stimuli while making reference to distal stimuli. In the main, I contend that electronic images of illegal drugs and users in an evocative telepresence are powerful stimuli, but they do not cause viewer perceptions.     

Organizational effectiveness. Primary care and the congruence model

The congruence model is a framework used to analyze organizational strengths and weaknesses and pinpoint specific areas for improving effectiveness. This article provides an overview of organizations as open systems, with examples in the primary care arena. It explains and applies the congruence model in the context of primary care issues and functions, including methods by which the model can be used to diagnose organizational problems and generate solutions. Changes needed in primary care due to the managed care environment, and areas of potential problems and sensitivities requiring organizational changes to meet market and regulatory demands now placed on PCOs are examined.     

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.     

The computerized patient record and confidentiality. The nabobs of negativism are wrong

The handwritten medical record has been the method of choice for documenting health care data since the last millennium. Given this successful tenure, it would be natural to greet any new information system that purports to be an advancement with skepticism. Moreover, physicians as a group are hardly progressive. Yet health care is taking a giant leap and is finally accepting computerization. The advantages and drawbacks of computerized information systems have long been thoroughly tested in such diverse industries as the military, banking, and the airlines. It is difficult to imagine any of these industries in their modern form without an advanced information system.