Cultural Context in Career Theory and Practice: Role Salience and Values

Career theory and practice have long emphasized person variables (e.g., abilities, needs, interests) and have only recently begun focusing on environmental variables in addressing cultural context issues. Contemporary emphasis on contextual variables reflects notable movement toward attaining cultural relevance in career theory and practice. Role salience and values, which are central to developmental perspectives on career and have been considered in other approaches, are key contextual variables that can be examined to make additional progress toward this goal. The author argues that examining the cultural dimensions of social roles and values can enrich theory and enhance practice regarding life‐career development.     

On the Value of derivative evaluations and random walk suppression in Markov Chain Monte Carlo algorithms

Two strategies that can potentially improve Markov Chain Monte Carlo algorithms are to use derivative evaluations of the target density, and to suppress random walk behaviour in the chain. The use of one or both of these strategies has been investigated in a few specific applications, but neither is used routinely. We undertake a broader evaluation of these techniques, with a view to assessing their utility for routine use. In addition to comparing different algorithms, we also compare two different ways in which the algorithms can be applied to a multivariate target distribution. Specifically, the univariate version of an algorithm can be applied repeatedly to one-dimensional conditional distributions, or the multivariate version can be applied directly to the target distribution.     

Non-parametric Back-projection of HIV Positive Tests using Multinomial and Poisson Settings

Back-projection is a commonly used method in reconstructing HIV incidence. Instead of using AIDS incidence data in back-projection, this paper uses HIV positive tests data. Both multinomial and Poisson settings are used. The two settings give similar results when a parametric form or step function is assumed for the infection curve. However, this may not be true when the HIV infection in each year is characterized by a different parameter. This paper attempts to use simulation studies to compare these two settings by constructing various scenarios for the infection curve. Results show that both methods give approximately the same estimates of the number of HIV infections in the past, whilst the estimates for HIV infections in the recent past differ a lot. The multinomial setting always gives a levelling-off pattern for the recent past, while the Poisson setting is more sensitive to the change in the shape of the HIV infection curve. Nonetheless, the multinomial setting gives a relatively narrower point-wise probability interval. When the size of the epidemic is large, the narrow probability interval may be under-estimating the true underlying variation.     

Coping with War: Three Strategies Employed by Adolescent Citizens of Sierra Leone

Children and adolescents in Sierra Leone have suffered through a decade of catastrophic violence and dislocation resulting from a brutal civil war. Many have been forced to flee their villages and have found refuge in United Nations refugee camps in neighboring countries. These children have witnessed the torture, maiming, and murder of family, friends, and neighbors. Some have been forced to carry arms or to serve as domestic and sexual servants to predatory rebel combatants. All have confronted enormous hardship and loss. This paper identifies three coping strategies employed by adolescents in a large refugee camp. Implications for professional practice are discussed.     

Continuous-time capture-recapture models with time variation and behavioural response

This paper develops a likelihood-based inference procedure for continuous-time capture-recapture models. The first-capture and recapture intensities are assumed to be in constant proportion but may otherwise vary arbitrarily through time. The full likelihood is partitioned into two factors, one of which is analogous to the likelihood in a special type of multiplicative intensity model arising in failure time analysis. The remaining factor is free of the non-parametric nuisance parameter and is easily maximized. This factor provides an estimator of population size and an asymptotic variance under a counting process framework. The resulting estimation procedure is shown to be equivalent to that derived from a martingale-based estimating function approach. Simulation results are presented to examine the performance of the proposed estimators.     

Modeling Fetal Death and Malformation in Developmental Toxicity Studies

We review approaches to dose-response modeling and risk assessment for binary data from developmental toxicity studies. In particular, we focus on jointly modeling fetal death and malformation and use a continuation ratio formulation of the multinomial distribution to provide a model for risk. Generalized estimating equations are used to account for clustering of animals within litters. The fitted model is then used to calculate doses corresponding to a specified level of excess risk. Two methods of arriving at a lower confidence limit or Benchmark dose are illustrated and compared. We also discuss models based on single binary end points and compare our approach to a binary analysis of whether or not the animal was 'affected' (either dead or malformed). The models are illustrated using data from four developmental toxicity studies in EG, DEHP, TGDM, and DYME conducted through the National Toxicology Program.     

A bargaining model and empirical analysis of strike activity across industries

This study extends the analysis on the inter-industry propensity to strike found in Leigh (1983) by (1) developing a more elaborate model, (2) developing proxies for all the parameters of the model, and (3) testing the modified model on two new data sets. The results suggest that strikes are more frequent in hazardous industries employing few women and where the average level of schooling is low. In addition, the evidence suggests strikes and wages may be simultaneously determined.