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.     

Cultural patterns in Dutch and Surinam nonverbal behavior: An analysis of simulated police/citizen encounters

Differences in nonverbal behavioral patterns in a simulated police interview setting were examined. One group of subjects was asked to tell the truth to a police officer whereas the other group was asked to deceive the officer. Major differences between our study and other deception studies include the distinction between nonverbal behavior displayed while listening and while speaking, and the inclusion of black subjects. Results show that there are differences in nonverbal behavior between deceivers and those who tell the truth, and generally support the finding that deception is associated with changes in vocal characteristics and hand and arm movements. However, differences in hand and arm movements occurred only while the deceiver was listening. Furthermore, findings showed that blacks looked less frequently at their discussion partner, smiled and laughed more, made more speech disturbances, spoke slower, and with more pitch raises, and were livelier in the sense that they made more trunk movements and gestures than whites.We wish to thank two anonymous reviewers for their constructive comments on an earlier draft. This project was in part supported by the PSYCHON Foundation, which is subsidized by the Netherlands Organization for Scientific Research.     

Men's experiences of violence: extent, nature and 'determinants'

We examined the extent, nature and 'determinants' of violence in a randomly selected sample of men from the general population (18–64 years, n = 520). The men were assessed on various factors (e.g. demographics). The design was cross-sectional and data were collected over eight consecutive weeks. About 68 per cent of the men reported experiencing violence at some point during their lifetime, and just over 14 per cent in the past 12 months. The violence occurred mainly in public and work settings, with threatening/aggressive language/physical assaults as the most common forms. The main perpetrators were strangers or clients. Sexual abuse was rare. Repeated/multiple abuses were common and injuries were sustained. The victims and non-victims were similar for many factors (e.g. alcohol use). Only younger age and being a blue-collar/low white-collar worker were risk factors for violence. Men's experiences of violence (e.g. physical assaults/multiple abuses) should be a source of concern as they can have profound negative effects. Extensive research on the impact of violence on men's health appears necessary in light of the present findings.     

A Randomized,Waiting-List-Controlled Study Shows That Brief,Mindfulness-Based Psychological Interventions Are Effective for Treatment of Women’s Low Sexual Desire

We evaluated two treatment conditions for low sexual desire in women: one where participants were administered a mindfulness-based treatment protocol and another with exercises focusing on scheduled sex and motivations for sex in addition to the aforementioned protocol. Seventy women (M_age 39.2, SD = 9.8) with complaints of low sexual desire were randomly allocated to one of these treatment conditions or a waiting-list condition. Participants attended four individual sessions and completed homework exercises. Questionnaire data were collected before and after treatment and at follow-ups three and six months later. Primary outcomes were the Female Sexual Function Index (FSFI) desire subdomain and the Sexual Interest and Desire Inventory–Female (SIDI-F). Secondary outcomes were the Female Sexual Distress Scale–Revised (FSDS-R), the Revised Dyadic Adjustment Scale (RDAS), the Perceived Relationship Quality Components Inventory (PRQC), and the Brief Symptom Inventory–18 (BSI-18). Women in both treatment conditions reported significantly higher sexual desire (FSFI desire d = 0.75 to 1.06) immediately following treatment, compared to the waiting list. Improvements were sustained at follow-up, accompanied by improvements in some secondary outcomes. We found no significant differences between the treatment conditions in terms of treatment effectiveness. Our study adds to the literature suggesting that mindfulness-based treatments are suitable options for treating low sexual desire in women.     

Dummy variables vs. category-wise models

Empirical research frequently involves regression analysis with binary categorical variables, which are traditionally handled through dummy explanatory variables. This paper argues that separate category-wise models may provide a more logical and comprehensive tool for analysing data with binary categories. Exploring different aspects of both methods, we contrast the two with a Monte Carlo simulation and an empirical example to provide a practical insight.     

Concurrent processing of heteroskedastic vector-valued mixture density models

We introduce a combined two-stage least-squares (2SLS)–expectation maximization (EM) algorithm for estimating vector-valued autoregressive conditional heteroskedasticity models with standardized errors generated by Gaussian mixtures. The procedure incorporates the identification of the parametric settings as well as the estimation of the model parameters. Our approach does not require a priori knowledge of the Gaussian densities. The parametric settings of the 2SLS_EM algorithm are determined by the genetic hybrid algorithm (GHA). We test the GHA-driven 2SLS_EM algorithm on some simulated cases and on international asset pricing data. The statistical properties of the estimated models and the derived mixture densities indicate good performance of the algorithm. We conduct tests on a massively parallel processor supercomputer to cope with situations involving numerous mixtures. We show that the algorithm is scalable.     

A General Statistical Framework for Multistage Designs

Abstract. The efficiency of observational studies may be increased by applying multistage sampling designs. It is, however, not always transparent how to construct such a design to obtain increased efficiency. We here present a general statistical framework for describing and constructing multistage designs. We also provide tools for efficiency and cost‐efficiency comparisons, to facilitate the choice of sampling scheme. The comparisons are based on Fisher information matrices and the results are presented in graphs, where either efficiency or cost‐adjusted efficiency is plotted against a normalized measure of cost. The former curve resides in the unit square and is analogous to the receiver operating characteristic curve used for testing.     

Marital Fertility Decline in the Netherlands: Child Mortality, Real Wages, and Unemployment, 1860–1939

Previous studies of the fertility decline in Europe are often limited to an earlier stage of the marital fertility decline, when the decline tended to be slower and before the large increase in earnings in the 1920s. Starting in 1860 (before the onset of the decline), this study follows marital fertility trends until 1939, when fertility reached lower levels than ever before. Using data from the Historical Sample of the Netherlands (HSN), this study shows that mortality decline, a rise in real income, and unemployment account for the decline in the Netherlands. This finding suggests that marital fertility decline was an adjustment to social and economic change, leaving little room for attitudinal change that is independent of social and economic change.