Fragmentation des économies nationales : L’économie des personnes recourant au « don » alimentaire au Québec comme observatoire

Plutôt que d’envisager comme inéluctable la fragmentation des économies nationales constatée dans plusieurs recherches, cet article étudie l’économie des personnes recourant à l’aide alimentaire afin de mettre au jour, selon les milieux sociaux et à l’échelle individuelle, l’appropriation sociale des transformations socioéconomiques dans les pays développés. Un modèle de description de la circulation de biens sociaux à la fois comme forme de réciprocité (suivant les trois obligations de Mauss) et comme action sociale réciproque (selon la conception des relations sociales et de la mémoire de Halbwachs) rend compte de l’organisation de la diversité des formes de circulation vécues.Rather than to consider as unavoidable the fragmentation of the national economies observed in different studies, this article looks at people resorting to food banks. It allows us to update the appropriation of socioeconomics transformations in developed countries at these people’s social environment scale as well as at their individual scale. A description model of goods circulation as a form of reciprocity (according to the three obligations as defined by Mauss) and as a form of reciprocal social action (according to Halbwachs’ conception of social relationships and social memory) brings to light the various organization schemes of these forms of reciprocity, as experienced by the subjects.En lugar de ver como ineluctable la fragmentación de las economías nacionales constatadas por varias investigaciones, este articulo estudia la economía de las personas que recurren a la ayuda alimentaria con el fin de ilustrar, de acuerdo con los medios sociales y con la escala individual de la apropiación social, dichas transformaciones socioeconómicas en los países desarrollados. Un modelo descriptivo de la circulación de bienes sociales en tanto que formas de reciprocidad que respeta las tres obligaciones de Mauss, y de la acción social recíproca según la concepción de las relaciones sociales y de la memoria de Halbwachs, describe las diferentes organizaciones de la diversidad de formas de circulación experimentadas

Études de la pathogénèse du VIH chez différents modèles murins

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Effect of age and sex on echocardiographic left ventricular diastolic function parameters in patients with preserved ejection fraction and normal valvular function

Background: We conducted a retrospective study to specify the effect of age and gender on echocardiographic left ventricular diastolic function parameters.Methods: We included echocardiograms done in our institution between 1995 and 2007, for which data on diastolic function were available. In order to target a population as close aspossible to healthy subjects, echocardiograms reporting abnormal contraction, valvulopathy or extreme data were excluded.Results: A total of 14,298 patients (mean age 58.53 years; men 49.1%) were included in the study. Sex did not influence E/A ratio (p = 0.298) but age decreased it significantly (p < 0.001). E/e ratio increased significantly with age (p < 0.001) and was higher in women than in men (p < 0.001). After the age of 40, more than 10% of the patients had an E/e ratio superior than 8.Conclusions: To our knowledge, this is the most imposing study — in terms of number of patients from first to tenth decade of life that were included — addressing the effect of age and gender on diastolic function. Our results stress the need for future prospective trials to establishnormal diastolic function parameters according to age and gender, notably for the E/e ratio for which a significant proportion of our population had a ratio superior of what is actually considered normal

Tactile feedback display with spatial and temporal resolutions.

We report the electronic recording of the touch contact and pressure using an active matrix pressure sensor array made of transparent zinc oxide thin-film transistors and tactile feedback display using an array of diaphragm actuators made of an interpenetrating polymer elastomer network. Digital replay, editing and manipulation of the recorded touch events were demonstrated with both spatial and temporal resolutions. Analog reproduction of the force is also shown possible using the polymer actuators, despite of the high driving voltage. The ability to record, store, edit, and replay touch information adds an additional dimension to digital technologies and extends the capabilities of modern information exchange with the potential to revolutionize physical learning, social networking, e-commerce, robotics, gaming, medical and military applications

High-cycle fatigue behavior of a laser powder bed fusion additive manufactured Ti-6Al-4V titanium: effect of pores and tested volume size

This work is focused on the effect of natural defect on the fatigue resistance of a laser powder bed fusion additively manufactured Ti-6Al-4V titanium. To reveal the fatigue strength variability and its sensitivity to the defect size, push-pull fatigue tests have been undertaken on specimens with different sizes of highly loaded volume of material. In order to easily vary the size of the highly loaded volume, specimens containing different numbers of surface hemispherical shape holes of 600 μm in diameter have been tested. This method also allowed to test small volume which triggered crack initiation from microstructural features. The fatigue damage mechanisms observed and the average natural defect size measured on the failure surfaces depend on the size of the highly stressed region. A higher fatigue strength is observed for smaller stressed volumes and defect free regions. To reduce the impact lack-of-fusion on fatigue and increase the probability of triggering crack initiation from a microstructural feature, the specimens were built in the horizontal direction. For specimens where fatigue cracks initiated at natural discontinuities, the results reported in a Kitagawa-Takahashi diagram revealed a critical defect size (√area ) in the range of 30 μm. In addition, a probabilistic approach based on the weakest link theory is proposed. The model describes a probabilistic Kitagawa-Takahashi diagram accounting for the size of both the highly stressed volume and the natural defect

Cancellous bone and theropod dinosaur locomotion. Part III—Inferring posture and locomotor biomechanics in extinct theropods, and its evolution on the line to birds

This paper is the last of a three-part series that investigates the architecture of cancellous bone in the main hindlimb bones of theropod dinosaurs, and uses cancellous bone architectural patterns to infer locomotor biomechanics in extinct non-avian species. Cancellous bone is highly sensitive to its prevailing mechanical environment, and may therefore help further understanding of locomotor biomechanics in extinct tetrapod vertebrates such as dinosaurs. Here in Part III, the biomechanical modelling approach derived previously was applied to two species of extinct, non-avian theropods, Daspletosaurus torosus and Troodon formosus. Observed cancellous bone architectural patterns were linked with quasi-static, three-dimensional musculoskeletal and finite element models of the hindlimb of both species, and used to derive characteristic postures that best aligned continuum-level principal stresses with cancellous bone fabric. The posture identified for Daspletosaurus was largely upright, with a subvertical femoral orientation, whilst that identified for Troodon was more crouched, but not to the degree observed in extant birds. In addition to providing new insight on posture and limb articulation, this study also tested previous hypotheses of limb bone loading mechanics and muscular control strategies in non-avian theropods, and how these aspects evolved on the line to birds. The results support the hypothesis that an upright femoral posture is correlated with bending-dominant bone loading and abduction-based muscular support of the hip, whereas a crouched femoral posture is correlated with torsion-dominant bone loading and long-axis rotation-based muscular support. Moreover, the results of this study also support the inference that hindlimb posture, bone loading mechanics and muscular support strategies evolved in a gradual fashion along the line to extant birds

Insights into the Ecology and Evolutionary Success of Crocodilians Revealed through Bite-Force and Tooth-Pressure Experimentation

BackgroundCrocodilians have dominated predatory niches at the water-land interface for over 85 million years. Like their ancestors, living species show substantial variation in their jaw proportions, dental form and body size. These differences are often assumed to reflect anatomical specialization related to feeding and niche occupation, but quantified data are scant. How these factors relate to biomechanical performance during feeding and their relevance to crocodilian evolutionary success are not known.Methodology/Principal FindingsWe measured adult bite forces and tooth pressures in all 23 extant crocodilian species and analyzed the results in ecological and phylogenetic contexts. We demonstrate that these reptiles generate the highest bite forces and tooth pressures known for any living animals. Bite forces strongly correlate with body size, and size changes are a major mechanism of feeding evolution in this group. Jaw shape demonstrates surprisingly little correlation to bite force and pressures. Bite forces can now be predicted in fossil crocodilians using the regression equations generated in this research.Conclusions/SignificanceCritical to crocodilian long-term success was the evolution of a high bite-force generating musculo-skeletal architecture. Once achieved, the relative force capacities of this system went essentially unmodified throughout subsequent diversification. Rampant changes in body size and concurrent changes in bite force served as a mechanism to allow access to differing prey types and sizes. Further access to the diversity of near-shore prey was gained primarily through changes in tooth pressure via the evolution of dental form and distributions of the teeth within the jaws. Rostral proportions changed substantially throughout crocodilian evolution, but not in correspondence with bite forces. The biomechanical and ecological ramifications of such changes need further examination

Substantially improved pharmacokinetics of recombinant human butyrylcholinesterase by fusion to human serum albumin

<p>Abstract</p> <p>Background</p> <p>Human butyrylcholinesterase (huBChE) has been shown to be an effective antidote against multiple LD₅₀of organophosphorus compounds. A prerequisite for such use of huBChE is a prolonged circulatory half-life. This study was undertaken to produce recombinant huBChE fused to human serum albumin (hSA) and characterize the fusion protein.</p> <p>Results</p> <p>Secretion level of the fusion protein produced <it>in vitro </it>in BHK cells was ~30 mg/liter. Transgenic mice and goats generated with the fusion constructs expressed in their milk a bioactive protein at concentrations of 0.04–1.1 g/liter. BChE activity gel staining and a size exclusion chromatography (SEC)-HPLC revealed that the fusion protein consisted of predominant dimers and some monomers. The protein was confirmed to have expected molecular mass of ~150 kDa by Western blot. The purified fusion protein produced <it>in vitro </it>was injected intravenously into juvenile pigs for pharmacokinetic study. Analysis of a series of blood samples using the Ellman assay revealed a substantial enhancement of the plasma half-life of the fusion protein (~32 h) when compared with a transgenically produced huBChE preparation containing >70% tetramer (~3 h). <it>In vitro </it>nerve agent binding and inhibition experiments indicated that the fusion protein in the milk of transgenic mice had similar inhibition characteristics compared to human plasma BChE against the nerve agents tested.</p> <p>Conclusion</p> <p>Both the pharmacokinetic study and the <it>in vitro </it>nerve agent binding and inhibition assay suggested that a fusion protein retaining both properties of huBChE and hSA is produced <it>in vitro </it>and <it>in vivo</it>. The production of the fusion protein in the milk of transgenic goats provided further evidence that sufficient quantities of BChE/hSA can be produced to serve as a cost-effective and reliable source of BChE for prophylaxis and post-exposure treatment.</p

Experimental and numerical investigations of the electro-viscoelastic behavior of VHB 4905TM

Dielectric elastomers are a class of electro-active polymers (EAPs) that can be used for the development of simple soft actuators, sensors and energy harvesters. Their operation principle is based on the interaction of quasi-static electric charges in combination with soft dielectrics and deformable electrodes. Due to their ability to undergo large deformations with a time dependent material response of the underlying polymer, the mechanical behaviors of EAPs can be described by a finite strain viscoelastic material model [1]. This model is here augmented in order to account for the influence of the electro-mechanical coupling. In this contribution we pursue a comprehensive electro-mechanical characterization of the popular dielectric polymer VHB 4905™. In contrast to the results of the electro-mechanical experiments published previously [2] all of these experiments are conducted without the application of a pre-stretch and are therefore well suited for the identification of the coupling parameters of the material model. The presented model shows excellent agreements with experimental findings