La dialectique socialisation/individualisation à l’œuvre dans les pratiques culturelles des jeunes de la génération numérique

Ce mémoire cherche à concevoir en théorie la dialectique socialisa-tion/individualisation à l’œuvre dans la formation et la transmission des goûts et pratiques culturels chez les jeunes adultes. L'analyse de dix entretiens conduits auprès de jeunes Montréalais âgés de 18 à 24 ans révèle que la socialisation sous l’égide de la famille et de l’école reste active sans être coercitive du fait qu’elle s'avère propice à la capacité des jeunes à se concevoir sous leur propre gouverne et à développer leurs propres goûts en matière de pratiques culturelles. Les pairs jouent également un rôle à cet égard, rôle amplifié par les moyens numériques. Les relations entre pairs génèrent une espèce de tension entre conformité au groupe et volonté d’être soi-même et de pouvoir agir à sa guise. Les nouvelles technologies d’information et de communication, quant à elles, se révèlent de nos jours sources de socialisation et d’individualisation en donnant accès à des « réseaux » en vertu desquels s’infléchissent les goûts et les préférences qui façonnent la pratique de la culture tout en permettant aux jeunes d’avoir les coudées franches pour les développer par eux-mêmes.This dissertation seeks to conceptualize the socialization/individualization dialectic at work in the formation and transmission of cultural tastes and practices among young adults. The analysis of ten interviews, conducted with young Montrealers aged 18 to 24, reveals that socialization operating within the family and school remains active without being coercive, because it proves favourable to the aptitude of young people to define themselves autonomously and to develop their own tastes in cultural practices. Peers also play a role in this regard, a role amplified by digital means. Relationships between peers generate tensions between group conformity and willingness to be authentic and to act upon one’s behalf. New technologies of information and communication, furthermore, appear as a source of socialization and individualization by providing access to "networks" that inflect the tastes and preferences shaping the practice of culture, while simultaneously allowing young adults the freedom to develop themselves

The mitogen-activated protein kinase kinase kinase dual leucine zipper-bearing kinase (DLK) acts as a key regulator of keratinocyte terminal differentiation.

In the skin, epithelial cells undergo a terminal differentiation program leading to the formation of the stratum corneum. Although it is expected that the last phases of this process must be tightly regulated since it results in cell death, the signaling pathways involved in this induction remain ill defined. We now report that a single kinase, the mitogen-activated protein kinase kinase kinase dual leucine zipper-bearing kinase (DLK), acts in the epidermis to promote the terminal differentiation of human keratinocytes. In support of this notion, we showed that DLK expression was restricted to the granular layer in situ. In addition, cultured keratinocytes infected with a recombinant adenovirus expressing DLK exhibited morphological and biochemical changes, including a suprabasal localization, altered cell shape, compacted cytoplasm, DNA fragmentation, and the up-regulation of filaggrin, that are reminiscent of a terminally differentiated phenotype. Moreover the expression of wild-type DLK in keratinocytes stimulated transglutaminase activity and the consequent formation of the cornified cell envelope, while a kinase-inactive variant of DLK did not. Together these results identify DLK as a signaling molecule implicated in the regulation of keratinocyte terminal differentiation and cornification

Valorisation de matières premières locales pour l’alimentation des poulets en agriculture biologique

100 % organic feeding for monogastrics is a challenge for poultry value chain and feed industry. 100 % organic diets without including conventional protein concentrate is a challenge : this might increase the importation of organic proteins (soya) and involve risk on technical and economical performances. This article is a synthesis of different research projects lead in France and in Europe. Nutritional value of organic raw material is highly variable, especially oleaginous meal (whatever the process). Increasing knowledge about nutritional value of organic raw material is needed to support 100 % organic feeding. Even if different organic raw material could be used in diets, this material is not sufficiently available with regard to their quantity (French soya, organic maize gluten, sesame meal), their price (nuttle, hempseeds, spirulina, etc…) and/or there is regulation lock-in (fish meal, insect meal, etc…). In turn, 100 % organic feeding could increase the organic soya needs and importation. Experimental results showed supplementary explained by an increase of feeding costs and potentially an increase of feed conversion ratio. This negative impact could be counterbalanced with feeding strategies (less protein in finishing) combined with a high protein value of free range area. Increasing local raw material quality and availability and improving free range as nutrient source are promising options but would require additional experiment

The Apoptotic Regulator Nrz Controls Cytoskeletal Dynamics via the Regulation of Ca2+ Trafficking in the Zebrafish Blastula

SummaryBcl-2 family members are key regulators of apoptosis. Their involvement in other cellular processes has been so far overlooked. We have studied the role of the Bcl-2 homolog Nrz in the developing zebrafish. Nrz was found to be localized to the yolk syncytial layer, a region containing numerous mitochondria and ER membranes. Nrz knockdown resulted in developmental arrest before gastrulation, due to free Ca2+ increase in the yolk cell, activating myosin light chain kinase, which led to premature contraction of actin-myosin cables in the margin and separation of the blastomeres from the yolk cell. In the yolk syncytial layer, Nrz appears to prevent the release of Ca2+ from the endoplasmic reticulum by directly interacting with the IP3R1 Ca2+ channel. Thus, the Bcl-2 family may participate in early development, not only by controlling apoptosis but also by acting on cytoskeletal dynamics and cell movements via Ca2+ fluxes inside the embryo

Aménagements des parcours de poulets Label Rouge et Biologiques

La présence d'un parcours est un élément majeur caractérisant les productions de volailles sous signes de qualité Label Rouge et Biologique. Pour permettre la durabilité de ces modes de production, il est nécessaire d'optimiser la gestion des parcours, afin de concilier au mieux les besoins des volailles, la production d'un revenu supplémentaire pour l'éleveur et une gestion environnementale pertinente. Pour cela, il était avant tout nécessaire de connaître la diversité des caractéristiques des parcours existants. Une enquête a été réalisée auprès des éleveurs de différents bassins de production français, et a permis de décrire les aménagements arborés des parcours, et les pratiques de gestion. Sept types d'aménagements des parcours ont été mis en évidence selon la présence ou non de haies périphériques, d'arbustes à proximité des trappes des bâtiments à vocation d'aménagements zootechniques, d'arbres à distance plus ou moins éloignée du bâtiment, de plantations arborées entre ces deux zones de parcours. Cette typologie permet d'apporter des préconisations d'amélioration adaptées à chaque situation

Differential binding of the transcription factors Sp1, AP-1, and NFI to the promoter of the human α5 integrin gene dictates its transcriptional activity

Purpose. Damage to the corneal epithelium results in the massive secretion of fibronectin (FN) shortly after injury and induces the expression of its integrin receptor α5β1. The authors reported previously that FN induces α5 expression in human corneal epithelial cells and rabbit corneal epithelial cells by altering the binding of the transcription factor (TF) Sp1 to a regulatory element from the α5 promoter that it is also flanked by binding sites for the TFs NFI and AP-1. Here, they assessed the function of NFI and AP-1 on α5 gene expression and evaluated the contribution of FN to their overall regulatory influence. Methods. TF binding to the α5 promoter was evaluated in vitro by electrophoretic mobility shift assays and in vivo by ligation-mediated PCR or chromatin immunoprecipitation. TFs expression was monitored by Western blot, whereas their influence was assessed by transfection and RNAi analyses. Results. Coexpression of Sp1, NFI, and AP-1 was demonstrated in all cell types, and each TF was shown to bind efficiently to the α5 promoter. Whereas both AP-1 and Sp1 activated expression directed by the α5 promoter, NFI functioned as a potent repressor of that gene. Interestingly, FN could either promote or repress α5 promoter activity in a cell density–dependent manner by differentially altering the ratio of these TFs. Conclusions. These results suggest that α5 gene expression is likely dictated by subtle alterations in the nuclear ratio of TFs that either repress (NFI) or activate (Sp1 and AP-1) α5 transcription in corneal epithelial cells

In vivo remodeling of fibroblast-derived vascular scaffolds implanted for 6 months in rats

There is a clinical need for tissue-engineered small-diameter (<6 mm) vascular grafts since clinical applications are halted by the limited suitability of autologous or synthetic grafts. This study uses the self-assembly approach to produce a fibroblast-derived decellularized vascular scaffold (FDVS) that can be available off-the-shelf. Briefly, extracellular matrix scaffolds were produced using human dermal fibroblasts sheets rolled around a mandrel, maintained in culture to allow for the formation of cohesive and three-dimensional tubular constructs, and decellularized by immersion in deionized water. The FDVSs were implanted as an aortic interpositional graft in six Sprague-Dawley rats for 6 months. Five out of the six implants were still patent 6 months after the surgery. Histological analysis showed the infiltration of cells on both abluminal and luminal sides, and immunofluorescence analysis suggested the formation of neomedia comprised of smooth muscle cells and lined underneath with an endothelium. Furthermore, to verify the feasibility of producing tissue-engineered blood vessels of clinically relevant length and diameter, scaffolds with a 4.6 mm inner diameter and 17 cm in length were fabricated with success and stored for an extended period of time, while maintaining suitable properties following the storage period. This novel demonstration of the potential of the FDVS could accelerate the clinical availability of tissue-engineered blood vessels and warrants further preclinical studies

BMC Nephrol

An amendment to this paper has been published and can be accessed via the original article

Multi-disciplinary investigation of fluid seepage on an unstable margin: The case of the Central Nile deep sea fan

We report on a multidisciplinary study of cold seeps explored in the Central Nile deep-sea fan of the Egyptian margin. Our approach combines in situ seafloor observation, geophysics, sedimentological data, measurement of bottom-water methane anomalies, pore-water and sediment geochemistry, and 230Th/U dating of authigenic carbonates. Two areas were investigated, which correspond to different sedimentary provinces. The lower slope, at ∼ 2100 m water depth, indicates deformation of sediments by gravitational processes, exhibiting slope-parallel elongated ridges and seafloor depressions. In contrast, the middle slope, at ∼ 1650 m water depth, exhibits a series of debris-flow deposits not remobilized by post-depositional gravity processes. Significant differences exist between fluid-escape structures from the two studied areas. At the lower slope, methane anomalies were detected in bottom-waters above the depressions, whereas the adjacent ridges show a frequent coverage of fractured carbonate pavements associated with chemosynthetic vent communities. Carbonate U/Th age dates (∼ 8 kyr BP), pore-water sulphate and solid phase sediment data suggest that seepage activity at those carbonate ridges has decreased over the recent past. In contrast, large (∼ 1 km2) carbonate-paved areas were discovered in the middle slope, with U/Th isotope evidence for ongoing carbonate precipitation during the Late Holocene (since ∼ 5 kyr BP at least). Our results suggest that fluid venting is closely related to sediment deformation in the Central Nile margin. It is proposed that slope instability leads to focused fluid flow in the lower slope and exposure of ‘fossil’ carbonate ridges, whereas pervasive diffuse flow prevails at the unfailed middle slope