Model averaging inconcentration–QT analyses

This article describes how a frequentist model averaging approach can be used for concentration–QT analyses in the context of thorough QTc studies. Based on simulations, we have concluded that starting from three candidate model families (linear, exponential, and Emax) the model averaging approach leads to treatment effect estimates that are quite robust with respect to the control of the type I error in nearly all simulated scenarios; in particular, with the model averaging approach, the type I error appears less sensitive to model misspecification than the widely used linear model. We noticed also few differences in terms of performance between the model averaging approach and the more classical model selection approach, but we believe that, despite both can be recommended in practice, the model averaging approach can be more appealing because of some deficiencies of model selection approach pointed out in the literature. We think that a model averaging or model selection approach should be systematically considered for conducting concentration–QT analyses. Copyright © 2016 John Wiley & Sons, Ltd.     

On the robustness of the generalized fused lasso to prior specifications

Using networks as prior knowledge to guide model selection is a way to reach structured sparsity. In particular, the fused lasso that was originally designed to penalize differences of coefficients corresponding to successive features has been generalized to handle features whose effects are structured according to a given network. As any prior information, the network provided in the penalty may contain misleading edges that connect coefficients whose difference is not zero, and the extent to which the performance of the method depend on the suitability of the graph has never been clearly assessed. In this work we investigate the theoretical and empirical properties of the adaptive generalized fused lasso in the context of generalized linear models. In the fixed \(p\) setting, we show that, asymptotically, adding misleading edges in the graph does not prevent the adaptive generalized fused lasso from enjoying asymptotic oracle properties, while forgetting suitable edges can be more problematic. These theoretical results are complemented by an extensive simulation study that assesses the robustness of the adaptive generalized fused lasso against misspecification of the network as well as its applicability when theoretical coefficients are not exactly equal. Our contribution is also to evaluate the applicability of the generalized fused lasso for the joint modeling of multiple sparse regression functions. Illustrations are provided on two real data examples.     

Health Risk Assessment of a Modern Municipal Waste Incinerator

During the modernization of the municipal waste incinerator (MWI, maximum capacity of 180,000 tons per year) of Metropolitan Grenoble (405,000 inhabitants), in France, a risk assessment was conducted, based on four tracer pollutants: two volatile organic compounds (benzene and 1, 1, 1 trichloroethane) and two heavy metals (nickel and cadmium, measured in particles). A Gaussian plume dispersion model, applied to maximum emissions measured at the MWI stacks, was used to estimate the distribution of these pollutants in the atmosphere throughout the metropolitan area. A random sample telephone survey (570 subjects) gathered data on time-activity patterns, according to demographic characteristics of the population. Life-long exposure was assessed as a time-weighted average of ambient air concentrations. Inhalation alone was considered because, in the Grenoble urban setting, other routes of exposure are not likely. A Monte Carlo simulation was used to describe probability distributions of exposures and risks. The median of the life-long personal exposures distribution to MWI benzene was 3.2·10^–5 g/m³ (20th and 80th percentiles = 1.5·10^–5 and 6.5·10^–5 g/m³), yielding a 2.6·10^–10 carcinogenic risk (1.2·10^–10–5.4·10^–10). For nickel, the corresponding life-time exposure and cancer risk were 1.8·10^–4 g/m³ (0.9.10^–4 – 3.6·10^–4 g/m³) and 8.6·10^–8 (4.3·10^–8–17.3·10^–8); for cadmium they were respectively 8.3·10^–6 g/m³ (4.0·10^–6–17.6·10^–6) and 1.5·10^–8 (7.2·10^–9–3.1·10^–8). Inhalation exposure to cadmium emitted by the MWI represented less than 1% of the WHO Air Quality Guideline (5 ng/m³), while there was a margin of exposure of more than 10⁹ between the NOAEL (150 ppm) and exposure estimates to trichloroethane. Neither dioxins nor mercury, a volatile metal, were measured. This could lessen the attributable life-long risks estimated. The minute (VOCs and cadmium) to moderate (nickel) exposure and risk estimates are in accord with other studies on modern MWIs meeting recent emission regulations, however.     

Effects of long-term landscape dynamics and city growth on biodiversity in the Mediterranean: the case study of Montpellier,France

In the Mediterranean, long-term land-use changes have resulted into landscape mosaics composed of very few ancient woodland remnants scattered across extended post-agricultural woodlands. Patches of ancient woodlands are now suffering rapid urban growth that reduces their area and impact their associated biodiversity. Here we use the case study of Montpellier, one of the most dynamic cities in France, to 1) characterize temporal changes in land covers (between 1860 and 2006) in its area, and 2) using two guilds of fungal bioindicators (i.e., polypores and lichens), to compare biodiversity stakes between ancient and secondary Mediterranean woodlands. We used a combination of historical maps, archives, fungal collections and field survey in eight Quercus ilex patches (4 ancient versus 4 recent replicates) to reconstruct landscapes dynamics and assess biodiversity changes. From the 19th to the 21st century, over half (52.4%) of the ancient woodlands within Montpellier were replaced by other land covers, mainly by urban equipment, while secondary patches (16.8% of the total area) were naturally established. Remaining ancient woodlands show multi-layered vegetation made of multi-secular Pinus halepensis dominating a dynamic understorey made of Quercus ilex and various Mediterranean shrubs. Polypores, but not macrolichens, tended to differ in community composition between ancient and recent woodland patches, with the highest diversity found in ancient woodlands. This study highlights that urban woodland patches of contrasted histories harbour distinct biodiversity stakes to be included in urban planning and provide valuable areas to evaluate biodiversity patterns and dynamics.     

Local perceptions of socio-ecological drivers and effects of coastal armoring: the case of Moorea,French Polynesia

Population and Environment - This paper presents a transdisciplinary study focusing on the socio-ecological mechanisms at play in the alteration of Moorea’s (French Polynesia) coastline....     

Factors Constraining Building Effective and Fair Geographical Indications for Coffee: Insights from a Dominican Case Study

The commodity nature of green coffee is the main cause of the ‘coffee paradox’ (falling producer prices and rising consumer prices). Geographical Indications (GIs) may be an effective ‘decommodifier’ of the coffee market, but many constraints have to be overcome. Based on an analysis of how the characteristics of the coffee production system shape the positions of local stakeholders and, thus, the GI building process, this article identifies some constraining factors that can seriously undermine the capacity the GI has to decommodify the market and attain a fairer distribution of the benefits for local producers.     

A new measure of association

This paper presents a new measure of association. It is applicable to polytomies of either categorical or numerical type. It has the desirable property of being 0 if and only if the polytomies are independent. Its properties are studied and compared to those of existing measures. An interpretation of it is given. One situation where it is particularly useful is in measuring the ability to predict one polytomy given knowledge of the other. An example is given where the proposed measure is more relevant in describing the degree of association between two polytomies than are any of the existing measures. The corresponding sample quantity is presented and its asymptotic properties are studied. A discussion of its use in inference is given. The test for independence based on this measure is contrasted with the chi-square test.     

A Simplified Approach to Risk Assessment Based on System Dynamics: An Industrial Case Study

Seveso plants are complex sociotechnical systems, which makes it appropriate to support any risk assessment with a model of the system. However, more often than not, this step is only partially addressed, simplified, or avoided in safety reports. At the same time, investigations have shown that the complexity of industrial systems is frequently a factor in accidents, due to interactions between their technical, human, and organizational dimensions. In order to handle both this complexity and changes in the system over time, this article proposes an original and simplified qualitative risk evaluation method based on the system dynamics theory developed by Forrester in the early 1960s. The methodology supports the development of a dynamic risk assessment framework dedicated to industrial activities. It consists of 10 complementary steps grouped into two main activities: system dynamics modeling of the sociotechnical system and risk analysis. This system dynamics risk analysis is applied to a case study of a chemical plant and provides a way to assess the technological and organizational components of safety.     

L’Europe sociale : créativité institutionnelle communautaire et réalités nationales

“Social Europe” has been constructed following 50 years of EEC and EU policy-making, which has gradually extricated social questions from a pure rationale of economic integration in order to turn it into a lever for European political integration. The theoretical and disciplinary viewpoints are presented that, together, help us better understand the processes at work. Attention is drawn to three of them. First of all, the evolutionary process of building the EU accounts both for the differences between social Europe and national welfare systems, and for an ongoing process of institutional creation through an accumulation of EU legal achievements (acquis). Secondly, the expansion of the EU to twelve new member states lacking robust labor relation systems, along with globalization, represents a challenge for the future of the “European social model”. Finally, social Europe has not yet undergone an assessment. Problems arise owing to the short shrift given by treaties to questions of social legislation or redistribution, but the “Europeanization of national policies” apparently opens a way toward overcoming these obstacles.