Compte-rendu de lecture : Mercure, Daniel et Vultur, Mircea (2010). La signification du travail : nouveau modèle productif et ethos du travail au Québec. Québec, Canada : Les Presses de l’Université Laval, 290 p.

International audienceQuel sens les Québécois de l’ère postfordiste donnent-ils à leur activité professionnelle alors qu’ils sont confrontés à une plus grande flexibilité, une autonomie accrue et une déresponsabilisation des employeurs quant à leur développement professionnel? Dans La signification du travail : nouveau modèle productif et ethos du travail au Québec, les sociologues Daniel Mercure (Département de sociologie, Université Laval) et Mircea Vultur (Centre Urbanisation Culture Société, Institut national de la recherche scientifique) tentent de répondre à ce questionnement. À la suite des grandes mutations que le monde du travail a connues au Québec et partout en Occident au cours des dernières décennies, les auteurs ont senti un besoin criant de faire le point sur « la place du travail dans la hiérarchie des valeurs de la population active québécoise et de dégager les différentes valeurs, attitudes et croyances associées au travail » (p. 7)

La formation professionnelle au Québec: le regard des élèves

S’appuyant sur les concepts de représentation sociale, personnelle et professionnelle, cette contribution s’intéresse aux représentations de la formation professionnelle québécoise. Des analyses de contenu de 53 entrevues avec des élèves montrent que cette voie est privilégiée en raison de ses spécificités pédagogiques, de la possibilité d’apprendre un métier et des perspectives d’insertion qu’elle offre. La formation professionnelle semble socialement dévalorisée, tout en étant valorisante pour l’individu. Cette vision contraste avec celle des pays, comme la Suisse, où cette voie est valorisée, mais sélective. Ces résultats soulignent l’importance de considérer l’influence des représentations et du contexte institutionnel sur les choix d’orientation.Based on the concepts of social, personal, and vocational representations, this contribution analyzes the portrayal of vocational education and training (VET) in Quebec. Content analyses of 53 interviews with students show that VET is preferred because of its pedagogical specificities, the opportunity to learn a trade and the attractive professional integration it assures. VET seems socially not valued, while being worthwhile for the individual. This vision contrasts with that of countries such as Switzerland, where VET is valued, but selective. Results then highlight the importance of considering the influence of representations and the institutional context on career decision

A comparative study at the global scale of ecological engineering techniques suitable for coral reef restoration

Afin de limiter l’effet des projets d’aménagement sur le déclin des écosystèmes coralliens tout en suivant une tendance déjà initiée en Europe et dans le monde, la législation française a, depuis 2009, rendu obligatoire la mise en place d’initiatives destinées à compenser les impacts subis par l’environnement. L’étude et la comparaison de 22 projets de restauration de récifs coralliens menés à travers le monde a permis de montrer que, depuis les nouvelles obligations réglementaires de compensation, les projets européens se sont multipliés, tentant de trouver des techniques de plus en plus efficaces à des coûts moindres. La mise en place de récifs artificiels et la transplantation corallienne sont à ce jour les deux outils d’ingénierie écologique apportant le plus de retours d’expériences positifs. Toutefois, malgré d’indéniables avancées en matière de recherche appliquée sur l’efficacité de ces techniques, mises en œuvre dans des conditions expérimentales, il ne semble pas exister à ce jour de méthodologie standard d’évaluation au cas par cas de leur application dans le cadre de mesures de compensation d’impacts environnementaux. Cette lacune méthodologique se traduit souvent par un décalage entre la restauration « scientifique » et la restauration « pratique » et par un désaccord fréquent sur les meilleures pratiques d’évaluation de la compensation.To limit the impact of development projects on the decline of coral ecosystem while following a trend already started in Europe and in the world; the French regulation has, since 2009, made obligatory the establishment of initiatives to offset the impacts caused to the environment. Artificial reefs and coral transplantation (or both together) are the two tools providing the most positive experience feedbacks worldwide. The study and comparison of 22 restoration projects of coral reefs conducted worldwide has shown that since the new regulatory obligations of mitigation, European projects have been multiplied, trying to find more effective techniques at lower costs. However, despite undeniable advances in applied research on the effectiveness of ecological engineering techniques used in experimental conditions, there is still no standard methodology of evaluation for each case of their application, in the context of mitigation measures for environmental impacts. This methodological gap often results in a gap between the “scientific” and the “practical” restorations and by frequent disagreement on the best practices for evaluation

Bifunctional coatings: coupling an organic adhesion promoter with an anticorrosion inorganic layer

International audienceIn this work, a multifunctional non-toxic chromium free treatment is proposed. Hexavalent chromium, largely used for anticorrosion surface treatments of aluminum alloys in aeronautics, will soon be completely banned due to its high toxicity (European REACH regulation) and new solutions are required. Here, in a first step, a polymeric film was grafted at the aluminum surface by the surface induced reduction of a diazonium salt. In a second step, the grafted surface was submitted to an anodization treatment, forming a thick aluminum oxide layer protecting the underlying metal against corrosion. No change in the organic coating was detected after the second step of the process. This leads to a multilayer coating, which provides competitive results regarding both the adhesion of paint and corrosion protection

Structure in Nascent Carbon Nanotubes Revealed by Spatially Resolved Raman Spectroscopy

The understanding of carbon nanotubes (CNT) growth is crucial for the control of their production. In particular, the identification of structural changes of carbon possibly occurring near the catalyst particle in the very early stages of their formation is of high interest. In this study, samples of nascent CNT obtained during nucleation step and samples of vertically aligned CNT obtained during growth step are analysed by combined spatially resolved Raman spectroscopy and X-Ray diffraction measurements. Spatially resolved Raman spectroscopy reveals that iron-based phases and carbon phases are co-localised at the same position, and indicates that sp2 carbon nucleates preferentially on iron-based particles during this nucleation step. Depth scan Raman spectroscopy analysis, performed on nascent CNT, highlights that carbon structural organisation is significantly changing from defective graphene layers surrounding the iron-based particles at their base up to multi-walled nanotube structures in the upper part of iron-based particles

Critical role of surface chemical modifications induced by length shortening on multi-walled carbon nanotubes-induced toxicity.

International audienceABSTRACT: Given the increasing use of carbon nanotubes (CNT) in composite materials and their possible expansion to new areas such as nanomedicine which will both lead to higher human exposure, a better understanding of their potential to cause adverse effects on human health is needed. Like other nanomaterials, the biological reactivity and toxicity of CNT were shown to depend on various physicochemical characteristics, and length has been suggested to play a critical role.We therefore designed a comprehensive study that aimed at comparing the effects on murine macrophages of two samples of multi-walled CNT (MWCNT) specifically synthesized following a similar production process (aerosol-assisted CVD), and used a soft ultrasonic treatment in water to modify the length of one of them.We showed that modification of the length of MWCNT leads, unavoidably, to accompanying structural (i.e. defects) and chemical (i.e. oxidation) modifications that affect both surface and residual catalyst iron nanoparticle content of CNT. The biological response of murine macrophages to the two different MWCNT samples was evaluated in terms of cell viability, pro-inflammatory cytokines secretion and oxidative stress. We showed that structural defects and oxidation both induced by the length reduction process are at least as responsible as the length reduction itself for the enhanced pro-inflammatory and pro-oxidative response observed with short (oxidized) compared to long (pristine) MWCNT.In conclusion, our results stress that surface properties should be considered, alongside the length, as essential parameters in CNT-induced inflammation, especially when dealing with a safe design of CNT, for application in nanomedicine for example

A comparative study on the enzymatic biodegradability of covalently functionalized double- and multi-walled carbon nanotubes

The assessment of the biodegradability potential of carbon nanotubes (CNTs) is a fundamental point towards their applications in materials science and biomedicine. Due to the continuous concerns about the fate of such type of nanomaterials, it is very important to understand if they can undergo degradation under certain conditions and if the morphology and structure of the nanotubes play a role in this process. For this purpose we have decided to undertake a comparative study on the enzymatic degradation of CNTs with concentric multilayers. Double-walled (DW) and multi-walled (MW) CNTs of various lengths, degrees of oxidation and functionalizations using different methods were treated with horseradish peroxidase (HRP). While all tested DWCNTs resulted resistant to the biodegradation, some of the MWCNTs were partially degraded by the enzyme. We have found that short oxidized multi-walled CNTs functionalized by amidation were reduced in length and presented a high amount of defects at the end of the period of treatment with HRP. This comparative study holds its importance in the understanding of the structural changes of different types of nanotubes towards the catalytic enzymatic degradation and will help to design safer CNTs for future applications

Fatty acid profile in peri-prostatic adipose tissue and prostate cancer aggressiveness in African-Caribbean and Caucasian patients

BACKGROUND: Genetic and nutritional factors have been linked to the risk of aggressive prostate cancer (PCa). The fatty acid (FA) composition of peri-prostatic adipose tissue (PPAT), which reflects the past FA intake, is potentially involved in PCa progression. We analysed the FA composition of PPAT, in correlation with the ethno-geographical origin of the patients and markers of tumour aggressiveness. METHODS: From a cohort of 1000 men treated for PCa by radical prostatectomy, FA composition of PPAT was analysed in 156 patients (106 Caucasians and 50 African-Caribbeans), 78 with an indolent tumour (ISUP group 1 + pT2 + PSA <10 ng/mL) and 78 with an aggressive tumour (ISUP group 4-5 + pT3). The effect of FA extracted from PPAT on in-vitro migration of PCa cells DU145 was studied in 72 patients, 36 Caucasians, and 36 African-Caribbeans. RESULTS: FA composition differed according to the ethno-geographical origin. Linoleic acid, an essential n-6 FA, was 2-fold higher in African-Caribbeans compared with Caucasian patients, regardless of disease aggressiveness. In African-Caribbeans, the FA profile associated with PCa aggressiveness was characterised by low level of linoleic acid along with high levels of saturates. In Caucasians, a weak and negative association was observed between eicosapentaenoic acid level (an n-3 FA) and disease aggressiveness. In-vitro migration of PCa cells using PPAT from African-Caribbean patients was associated with lower content of linoleic acid. CONCLUSION: These results highlight an important ethno-geographical variation of PPAT, in both their FA content and association with tumour aggressiveness

In silico Hierarchical Clustering of Neuronal Populations in the Rat Ventral Tegmental Area Based on Extracellular Electrophysiological Properties.

The ventral tegmental area (VTA) is a heterogeneous brain region, containing different neuronal populations. During recordings, electrophysiological characteristics are classically used to distinguish the different populations. However, the VTA is also considered as a region harboring neurons with heterogeneous properties. In the present study, we aimed to classify VTA neurons using approaches, in an attempt to determine if homogeneous populations could be extracted. Thus, we recorded 291 VTA neurons during extracellular recordings in anesthetized rats. Initially, 22 neurons with high firing rates (>10 Hz) and short-lasting action potentials (AP) were considered as a separate subpopulation, in light of previous studies. To segregate the remaining 269 neurons, presumably dopaminergic (DA), we performed analyses, using a combination of different electrophysiological parameters. These parameters included: (1) firing rate; (2) firing rate coefficient of variation (CV); (3) percentage of spikes in a burst; (4) AP duration; (5) Δt duration (i.e., time from initiation of depolarization until end of repolarization); and (6) presence of a notched AP waveform. Unsupervised hierarchical clustering revealed two neuronal populations that differed in their bursting activities. The largest population presented low bursting activities (17.5%). Within non-high-firing neurons, a large heterogeneity was noted concerning AP characteristics. In conclusion, this analysis based on conventional electrophysiological criteria clustered two subpopulations of putative DA VTA neurons that are distinguishable by their firing patterns (firing rates and bursting activities) but not their AP properties