Validation of Multimedia Models Assessing Exposure to PAHs—The SOLEX Study

Polluted soils have become a public health problem. While population exposure to soil pollutants is generally quantified using multimedia models, their estimations have not been validated, and studies that attempted to do so are scarce. The objective of the SOLEX study was to compare the predictions of pyrene exposure levels (converted into 1 hydroxypyrene) computed by several models with the results of urinary 1-hydropyrene (1-HOP) assays among 110 employees working at three sites polluted during their past use as manufactured gas plants. Four models were used: AERIS (Canada), CalTOX (California, USA), CLEA (UK), and HESP (The Netherlands). Three occupational exposure scenarios--with office, mixed, and outdoor workers--were constructed, based upon job activities during two measurement campaigns, one in winter and one in summer. The exposure levels estimated by the four models could differ markedly (from 7 up to 80 times) according to the exposure scenario. Also, the predominant exposure routes differed according to the model (direct soil ingestion for HESP and CalTOX, inhalation for AERIS, and dermal absorption for CLEA). The predictions of CalTOX are consistent with the 1-HOP measurements for all the scenarios. For HESP, the consistency is observed for the scenarios, office and mixed, for which the pyrene level in the soil is low. AERIS and CLEA yield results that are systematically above the 1-HOP measurements. This study confirms that validation of the models is crucial and points out to the need to proceed to assess components of the models that are the most influential using appropriate statistical analysis in combination with true field data.     

Convergence in the Social Welfare Systems in Europe: From Goal to Reality

The history of the social welfare systems in Europe in the postwar period appears as autonomous national processes because the construction of Europe which imposed common rules in many areas was equally consistent with the national development of social welfare systems, within each national culture. However, the idea of a common system of social protection has always remained linked to political and economic European construction which would create a more cohesive society. Many studies have analysed the trend of specific social policies and their convergence or divergence in Europe. Therefore, global convergence is often conceived as resulting from the domestic dynamics of each social risk. The paper focuses on one specific topic: the quantitative evaluation of convergence among the EU and OECD countries at the macroeconomic level. In the first part we explain the construction of social indicators which can assess the convergence or divergence of social expenditure in EU and OECD countries. In the second part we show many methodological problems and difficulties of interpretation of the social indicators. Then we see that the analysis of national trajectories of social expenditure and the link with economic development can enrich the analysis of convergence in social protection. Finally, the empirical analysis supports the idea of “adjustment” reforms rather than radical changes in a transitional period.     

Early stopping by using stochastic curtailment in a three-arm sequential trial

Summary. Interim analysis is important in a large clinical trial for ethical and cost considerations. Sometimes, an interim analysis needs to be performed at an earlier than planned time point. In that case, methods using stochastic curtailment are useful in examining the data for early stopping while controlling the inflation of type I and type II errors. We consider a three-arm randomized study of treatments to reduce perioperative blood loss following major surgery. Owing to slow accrual, an unplanned interim analysis was required by the study team to determine whether the study should be continued. We distinguish two different cases: when all treatments are under direct comparison and when one of the treatments is a control. We used simulations to study the operating characteristics of five different stochastic curtailment methods. We also considered the influence of timing of the interim analyses on the type I error and power of the test. We found that the type I error and power between the different methods can be quite different. The analysis for the perioperative blood loss trial was carried out at approximately a quarter of the planned sample size. We found that there is little evidence that the active treatments are better than a placebo and recommended closure of the trial.     

Sexual Activity and Weekly Contraceptive Discontinuation and Selection Among Young Adult Women in Michigan

Understanding young women’s contraceptive and pregnancy prevention behaviors is important for helping women and their partners control if and when they have children. Prior research on associations between patterns of sexual activity and contraceptive behaviors is limited. We assessed the influence of recent sexual activity on discontinuation and selection of specific contraceptive methods. We used weekly data from the Relationship Dynamics and Social Life (RDSL) study, a longitudinal 2.5-year population-based project that sampled woman ages 18 and 19 (N = 1,003) in one Michigan county. We estimated logistic and multinomial regression models that accounted for clustering of weekly observations within partnerships and women. Weekly discontinuation of longer-acting methods declined with increasing sexual activity in the past month, as did discontinuation of shorter-acting hormonal methods. Sexual activity was associated with decreased selection of condoms relative to other methods. Future research into life events that lead to changes in the frequency of sexual activity may provide insight into times when women are at risk of contraceptive discontinuation. These findings underscore the importance of anticipatory guidance in contraceptive counseling so that when women change their contraceptive behavior they are equipped in advance with resources to make safe transitions between methods.     

Causes,effects and mitigation of unreliable healthcare supplies

This study investigates the means by which hospitals can improve the reliability of their medical supply value streams. Field research involving pharmacy supplies in eight Australasian public sector hospitals utilised a rigorous, multi-method data collection procedure based around the uncertainty circle model. Value stream maturity, performance inhibitors and pathways to effective improvement are explored. The high levels of value stream uncertainty detected are commonly the result of process immaturity and poor inter-functional integration. Chief among the common root causes is failure by the executive to acknowledge the strategic value of medical supplies management, which ultimately leads to higher materials cost and increased risk of a medical mishap. The study demonstrates how managers can use systems thinking and a context-free performance benchmark to identify effective interventions and potentially transferable best practices.     

Hierarchical Bayesian models to assess between- and within-batch variability of pathogen contamination in food

Assessing within-batch and between-batch variability is of major interest for risk assessors and risk managers in the context of microbiological contamination of food. For example, the ratio between the within-batch variability and the between-batch variability has a large impact on the results of a sampling plan. Here, we designed hierarchical Bayesian models to represent such variability. Compatible priors were built mathematically to obtain sound model comparisons. A numeric criterion is proposed to assess the contamination structure comparing the ability of the models to replicate grouped data at the batch level using a posterior predictive loss approach. Models were applied to two case studies: contamination by Listeria monocytogenes of pork breast used to produce diced bacon and contamination by the same microorganism on cold smoked salmon at the end of the process. In the first case study, a contamination structure clearly exists and is located at the batch level, that is, between batches variability is relatively strong, whereas in the second a structure also exists but is less marked.     

Macroergonomic aspects in the design of development programs in IDCs

This paper revisits three reports on ergonomic aspects of development initiatives taking place in Industrially Developing Countries (IDCs). These include a macro-ergonomics intervention in a habitation community in Cape Verde (aimed at designing solutions contributing to sustainable development), the evolution of poultry growers' control strategies as an integrative broiler operation is introduced in Mozambique, and a set of macro-ergonomic considerations related to the Agro Forestry Village Project in Mozambique. The paper seeks to set the reviewed development endeavors against the backdrop of the goals of ergonomics interventions. This reflection may inform development agents in future processes of design and implementation of integrated community and work systems transformation.