Has the HIV Epidemic Peaked?

This study reviews the highly diverse regional and country patterns of HIV epidemics and discusses possible causes of the geographic variation in epidemic sizes. Past trends and projections of the epidemics are presented and the peak years of epidemics are estimated. The potential future impact of new prevention technologies is briefly assessed. A final section summarizes the future impact of the epidemic on key demographic variables. The main finding of this analysis is that the HIV epidemic reached a major turning point over the past decade. The peak years of HIV incidence rates are past for all regions, and the peaks of prevalence rates are mostly in the past except in Eastern Europe, where they are expected to peak in 2008. But owing in part to the life‐prolonging effect of antiretroviral therapy and to sustained population growth, the absolute number of infected individuals is expected to keep growing slowly in sub‐Saharan Africa and to remain near current levels worldwide, thus posing a continuing challenge to public health programs. No country is expected to see a decline in its population size between 2005 and 2050 that is attributable to high mortality related to AIDS.     

AN EMPIRICAL ANALYSIS OF THE TAX COURT'S DETERMINATION OF REASONABLE COMPENSATION

The determination of reasonable compensation is one of the most frequently contested issues between the taxpayer and the IRS. The major purpose of this study is to develop a multiple regression model to predict accurately the amount of compensation allowed by the Tax Court as a percent of the amount in dispute between the taxpayer and the IRS. In general, the taxpayer receives favorable treatment in Tax Court when contesting unreasonable compensation payments. The multiple regression model, developed using a stepwise procedure, is a good predictor of the compensation allowed by the court. The overall results have important implications for developing taxpayers' appeal strategies.     

Linking Changes in Parenting to Parent–Child Relationship Quality and Youth Self‐Control: The Strong African American Families Program

A randomized prevention trial was conducted contrasting families who took part in the Strong African American Families Program (SAAF), a preventive intervention for rural African American mothers and their 11‐year‐olds, with control families. SAAF is based on a conceptual model positing that changes in intervention‐targeted parenting behaviors would enhance responsive‐supportive parent–child relationships and youths' self‐control, which protect rural African American youths from substance use and early sexual activity. Parenting variables included involvement‐vigilance, racial socialization, communication about sex, and clear expectations for alcohol use. Structural equation modeling analyses indicated that intervention‐induced changes in parenting were linked with changes in responsive–supportive parent–child relationships and youth self‐control.     

A UNIFIED FRAMEWORK FOR MODELLING WILDLIFE POPULATION DYNAMICS†

This paper proposes a unified framework for defining and fitting stochastic, discrete‐time, discrete‐stage population dynamics models. The biological system is described by a state‐space model, where the true but unknown state of the population is modelled by a state process, and this is linked to survey data by an observation process. All sources of uncertainty in the inputs, including uncertainty about model specification, are readily incorporated. The paper shows how the state process can be represented as a generalization of the standard Leslie or Lefkovitch matrix. By dividing the state process into subprocesses, complex models can be constructed from manageable building blocks. The paper illustrates the approach with a model of the British grey seal metapopulation, using sequential importance sampling with kernel smoothing to fit the model.     

Perceptions by treatment staff of critical tasks in the treatment of the compulsive gambler

Seventy-five clinicians who treat compulsive gamblers were surveyed. Each rated 89 clinical tasks and responsibilities for importance in the treatment of this population. Analysis of those items for which a plurality of clinicians rated the item as critical was chosen as the criteria of importance. A principal components analysis was conducted to determine the underlying structure of clinical perceptions of importance. An eight-dimensional model was found to describe perceptions in the most satisfactory way. The analysis revealed five major and three minor clusters of tasks and responsibilities. The major dimensions were labeled as (1) self-help/social support, (2) crisis interventions, (3) behavioral resources for change, (4) psychodynamics of treatment, and (5) crisis severity. The minor dimensions were (6) knowledge and training, (7) ethics and sensitivity to needs, and (8) confidentiality and regulations. A brief discussion of the implications are presented.This research was supported in part by a grant from the Massachusetts Department of Public Health.     

Definitions of conflict and the legitimation of resources: The case of environmental risk

This paper examines the social construction of conflict over environmental health and safety issues (i.e., environmental risk). Four explanations for such conflict are commonly offered in the environmental policy literature. We examine the interests served by each. We hypothesize that environmental policy professionals hold definitions of conflict consistent with the values and interests of the organizations for which they work and the professions of which they are members. These definitions enhance the legitimacy of the resources those groups possess in relative abundance. Data from a survey of risk professionals are generally consistent with these hypotheses. We conclude by generalizing beyond environmental conflict to identify ways in which disputes about the nature of a social problem or conflict are often at the same time struggles to determine the value of the resources available to social movements and their opponents.An earlier version of the paper was presented at the 1984 annual meeting of the American Sociological Association. The views expressed herein do not necessarily represent those of George Mason University, George Washington University, or the National Research Council or any of its constituent units.     

A note on the four-colourability of pedigrees and its consequences for probability calculations

A graph representing the probabilistic dependences between genotypes of individuals in a pedigree is shown to be four-colourable. The consequences of this for computation of probabilities, using both exact and Markov chain Monte Carlo methods, is discussed. A four-colouring and triangulation of an inbred section of a pedigree of Red-Crowned Cranes is illustrated.     

Uncertainty and the Value of Information with Stochastic Losses from Global Warming

We present an uncertainty analysis conducted using CETA-R, a model in which the costs of climate change are specified as Risks of large losses. In this analysis, we assume that three key parameters may each take on "high" or "low" values, leading to eight possible states of the world. We then explore optimal policies when the state of the world is known, and under uncertainty. Also, we estimate the benefits of resolving uncertainty earlier. We find that the optimal policy under uncertainty is similar to the policy that is optimal when each of the key parameters is at its low value. We also find that the value of immediate uncertainty resolution rises sharply as the alternative to immediate resolution is increasingly delayed resolution.