When mobility makes sense: A qualitative and longitudinal study of the daily mobility of the elderly

A majority of North Americans hopes to grow old in the suburbs. This aspiration depends upon their ability to drive and their access to a car. Because it is essential for everyday travel, car-mobility in the suburbs is becoming a symbolic goal. The meanings of mobility for elderly will evolve over time, notably as a result of changes in autonomy. However, the mobility of older adults is mainly understood in terms of daily trips. Little research has considered the temporal dimension of aging as an evolving process. This study aimed at understanding with a qualitative and longitudinal perspective how older people stay (auto-)mobile in their house and their neighborhood against the need to adapt to reduced autonomy and mobility over time. A group of 22 suburbanites aged from 62 to 89 was interviewed in 1999 and in 2006. The results show that even if older people succeed in increasing their mobility, they are headed for inevitable immobility. Among the environmental adaptation strategies that were observed, the constructed behaviors, the dependencies demanding additional supports as well as the social life modulate different evolving experiences of the city: the shrinking city, the fragmented city, and the city by proxy. The built environment is at the heart of a complex process in which the adaptation of mobility contributes to the emergence of new residential experiences.     

Euarchontan affinity of Paleocene Afro-European adapisoriculid mammals and their origin in the late Cretaceous Deccan Traps of India

The controversial family Adapisoriculidae, a group of shrew-sized Paleocene mammals, had proposed relationships with insectivores, marsupials and more recently to plesiadapiforms. Adapisoriculid remains are numerous in the early Paleocene locality of Hainin, Belgium, and allow us a test of these different phylogenetic hypotheses. Here, we identify the first tarsal bones of adapisoriculid mammals. The highly specialised bones indicate an arboreal mode of life with euarchontan affinity. Moreover, the tarsal bones are morphologically very close to those of the late Cretaceous Deccanolestes from the Deccan intertrappean beds of India, and also share several characters with the Paleocene plesiadapiforms and the extant cynocephalid dermopterans. The adapisoriculid affinities of Deccanolestes are also confirmed by tooth morphology, indicating that Deccanolestes is a primitive member of this family. These phylogenetic affinities suggest a paleobiogeographic scenario for the family with dispersal either via East Africa or across the Tethys area.     

Detection of environmental clastogens and aneugens in human fibroblasts by cytokinesis-blocked micronucleus assay associated with immunofluorescent staining of CENP-A in micronuclei

The cytokinesis-blocked micronucleus (CBMN) assay, in combination with fluorescent in situ hybridization (FISH) of human pan-centromeric DNA probes, or with CREST antibodies that specifically stain kinetochore proteins, is widely used on several cell types. It distinguishes micronuclei containing one or several whole chromosomes, which are positively labeled (centromere positive micronucleus, C+MN, due to aneugenic effect), or acentric chromosome fragments, which are unlabeled due to the absence of centromere (centromere negative micronucleus, C−MN, due to clastogenic effect). However, the very slight level of the centromeric signals obtained with the FISH technique on primary human fibroblasts, a cell type commonly used in environmental genetic toxicology, leads to great difficulties in distinguishing C+MN and C−MN. Furthermore, the CREST technique may lead to inappropriate results particularly with regards to variations in antibody composition between patient sera. Our results show that the in vitro CBMN, in combination with immunofluorescence staining of CENP-A (centromere protein A), efficiently screens genotoxicants for their ability to induce clastogenic and/or aneugenic effects. We propose the in vitro CBMN assay in combination with immunofluorescence staining of CENP-A as a suitable tool in environmental genotoxicity testing of primary human fibroblasts.     

Beyond BAT: Selecting optimal combinations of available techniques,with an example from the limestone industry

Technological choices are multi-dimensional and thus one needs a multi-dimensional methodology to identify best available techniques. Moreover, in the presence of environmental externalities generated by productive activities, ‘best’ available techniques should be best from Society's point of view, not only in terms of private interests. In this paper we present a modeling framework based on methodologies appropriate to serve these two purposes, namely linear programming and internalization of external costs. We develop it as an operational decision tool, of interest for both firms and regulators, and we apply it to a plant in the lime industry. We show why, in this context, there is in general not a single best available technique (BAT), but well a best combination of available techniques to be used (BCAT).     

A theoretical and methodological framework for studying and modelling drivers’ mental representations

This article provides a synthetic overview of the research programme carried out at INRETS-LESCOT over the last 10 years, in view to studying and modelling the mental representations of car drivers. Theoretically, this research is in line with two complementary scientific traditions: Human Information Processing theories on the one hand, and theories of Operative Activity on the other. As discussed in Section 1 of the article, attention is given to the functional representations of drivers, constructed “by” and “for” the action, such as they are implemented in a driving situation, and taking into account both implicit and explicit dimensions. This aim directly impacts on the methodological approach implemented, in so far as it entails defining an “experimental continuum” ranging from naturalistic observations of the driving activity (on the open road), to setting up more controlled experimental protocols in order to permit in-depth, systematic and reproducible scientific investigations of drivers’ cognition. Section 2 of the article presents a synthetic view of these methods, while Section 3 presents several significant results obtained with them. Lastly, the final part of the article focuses on the computational formalism defined at INRETS-LESCOT (i.e. the driving schemas) designed to model driver knowledge and mental representations, and developed in a COgnitive Simulation MOdel of the DRIVEr called COSMODRIVE.     

Comparative study of different exposure routes on the biotransformation and genotoxicity of PAHs in the flatfish species, Scophthalmus maximus

In this study, laboratory experiments were carried out in order to come to a better understanding of the fate of polycyclic aromatic hydrocarbons (PAHs) in the marine environment and especially on their bioaccumulation, biotransformation and genotoxic effects in fish. Juveniles of turbot (Scophthalmus maximus) were exposed to PAHs through different routes via (1) a mixture of dissolved PAHs, (2) a PAH-polluted sediment and (3) an oil fuel elutriate. Fish were exposed 4 days followed by a 6-day depuration period. In each experiment, PAH concentrations in the seawater of the tanks were analysed regularly by gas chromatography coupled with mass spectrometry. Muscle and liver samples were also analysed for parent PAH levels and PAH bioconcentration factors were calculated. Biotransformation was evaluated by measuring the levels of PAH metabolites in fish bile. Genotoxicity was assessed by the alkaline comet assay. Regardless of exposure route, the parent PAH concentrations in the liver and muscle showed a peak level 1 day after the beginning of the exposure, followed by a decrease up to the background level towards the end of the experiment, except for the exposure to dissolved PAHs for which levels were relatively low throughout the study. As a consequence, no bioaccumulation was observed in fish tissues at the end of the experiment. In contrast, regardless of exposure routes, a rapid production of biliary metabolites was observed throughout the whole exposure experiment. This was especially true for 1-hydroxypyrene, the major metabolite of pyrene. After 6 days of recovery in clean water, a significant decrease in the total metabolite concentrations occurred in bile. Fish exposed through either route displayed a significant increase in DNA strand breaks after 4 days of exposure, and significant correlations were observed between the level of biliary PAH metabolites and the level of DNA lesions in fish erythrocytes. Overall results indicate that exposure to either a mixture of dissolved PAHs, a PAH-contaminated sediment or a dispersed oil fuel elutriate leads to biotransformation and increase in DNA damage in fish. The quantification of PAH metabolites in bile and DNA damage in erythrocytes appear to be suitable for environmental monitoring of marine pollution either in the case of accidental oil spills or sediment contamination.     

Concomitant Zn-Cd and Pb retention in a carbonated fluvio-glacial deposit under both static and dynamic conditions

The chemical and physical processes involved in the retention of 10(-2)M Zn, Pb and Cd in a calcareous medium were studied under saturated dynamic (column) and static (batch) conditions. Retention in columns decreased in order: Pb>Cd approximately Zn. In the batch experiments, the same order was observed for a contact time of less than 40h and over, Pb>Cd>Zn. Stronger Pb retention is in accordance with the lower solubility of Pb carbonates. However, the equality of retained Zn and Cd does not fit the solubility constants of carbonated solids. SEM analysis revealed that heavy metals and calcareous particles are associated. Pb precipitated as individualized Zn-Cd-Ca- free carbonated crystallites. All the heavy metals were also found to be associated with calcareous particles, without any change in their porosity, pointing to a surface/lattice diffusion-controlled substitution process. Zn and Cd were always found in concomitancy, though Pb fixed separately at the particle circumferences. The Phreeqc 2.12 interactive code was used to model experimental data on the following basis: flow fractionation in the columns, precipitation of Pb as cerrusite linked to kinetically controlled calcite dissolution, and heavy metal sorption onto proton exchanging sites (presumably surface complexation onto a calcite surface). This model simulates exchanges of metals with surface protons, pH buffering and the prevention of early Zn and Cd precipitation. Both modeling and SEM analysis show a probable significant decrease of calcite dissolution along with its contamination with metals.     

Bioremediation of halogenated compounds: comparison of dehalogenating bacteria and improvement of catalyst stability

Five bacterial strains were compared for halogenated compounds conversion in aqueous media. Depending on the strain, the optimal temperature for dehalogenase activity of resting cells varied from 30 to 45 degrees C, while optimal pH raised from 8.4 to 9.0. The most effective dehalogenase activity for 1-chlorobutane conversion was detected with Rhodococcus erythropolis NCIMB13064 and Escherichia coli BL21 (DE3) (DhaA). The presence of 2-chlorobutane or propanal in the aqueous media could inhibit the 1-chlorobutane transformation.     

Concentrations of chlorinated and brominated contaminants and their metabolites in serum of harbour seals and harbour porpoises

Harbour seals (Phoca vitulina) and harbour porpoises (Phocoena phocoena) are top predators in the North Sea and consequently accumulate a variety of pollutants in their tissues. Concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and their hydroxylated metabolites (HO-PCBs and HO-PBDEs) were measured in serum of wild harbour seals (n = 47) and captive harbour porpoises (n = 21). Both species exhibit long life spans and do not have extreme situations, such as complete fasting during periods of lactation, in their annual cycles. For PCBs, concentrations in adult males were slightly higher than in juveniles and lowest in juvenile females. For PBDEs, juveniles have higher levels than adult males and females, probably as a consequence of lactational transfer. However, differences between these age–gender groups were not statistical significant, indicating that individual variation was limited within each species, even without knowing the feeding status of the animals. Body condition, particularly emaciation, has a major influence on the levels of chlorinated and brominated contaminants in serum. Profiles of PCBs were CB 153 > CB 138 > CB 187 > CB 180 and CB 153 > CB 138 > CB 149 > CB 187 > CB 180 for harbour seals and porpoises respectively. For PBDEs, BDE 47 was the predominant congener followed by BDE 100 and 99 in both species. In harbour seals, concentrations of sum PCBs (median: 39,200 pg/ml) were more than 200 times higher than levels of sum PBDEs (median: 130 pg/ml) and almost 10 times higher than concentrations of sum HO-PCBs (4350 pg/ml). In harbour porpoises, concentrations of sum PCBs (median: 24,300 pg/ml) were about 20 times higher than concentrations of PBDEs (median: 1300 pg/ml). HO-PCBs were detected in only 4 harbour porpoises and this at very low concentrations. Naturally-produced MeO-PBDEs were only found in harbour porpoises at concentrations ranging from 120 to 810 pg/ml. HO-PBDEs were not found in any species. In general, harbour seals accumulate less compounds and have mostly lower concentrations than harbour porpoises possibly as a result of a better developed metabolism.