S’engager à titre de collaborateur bénévole dans un projet de recherche participative : les motivations d’un groupe d’aînés

Cet article rapporte les résultats d’une étude visant l’examen des motivations à la source de l’implication d’aînés au sein d’un projet national de recherche-action. Les données ont été recueillies au moyen d’entrevues en profondeur auprès d’aînés (n=5) engagés dans le volet montréalais du projet. Les résultats révèlent six grandes classes de motivations : changer les choses, utiliser ses habiletés et son expérience, travailler en équipe, faire preuve d’altruisme, conserver un statut et un rôle dans la société et, enfin, agir en lien avec sa philosophie de vie. Ces résultats corroborent en partie ceux qui ont été présentés dans les études antérieures. Cependant, les motivations liées à la poursuite d’activités et de façons de faire expérimentées dans le travail qui précède la retraite ressortent davantage. La discussion aborde les stratégies à privilégier pour faciliter l’implication d’aînés en recherche-action.The purpose of this study was to investigate factors related to the involvement of seniors in a national action-research project. Information was collected by in-depth interviews with the participants involved (n=5) in the Montreal site of the project. The elderly described six main motivations: changing things, using one’s skills and experience, working with a team, being altruistic, maintaining a status and a valued role in society and, finally, acting according to one’s philosophy and ideology of life. These data partly corroborate previous results. However, this study highlights the importance of motivations linked to pursuing activities and ways of doing things developed at work before retirement. Strategies aimed at facilitating the involvement of elderly in action-research projects are presented in the discussion

L'efficacité relative d'interventions en lecture orientées vers le contexte en première année

Québec Université Laval, Bibliothèque 201

Outil d'aide à la décision pour la conception de systèmes manufacturiers cellulaires

Ce mémoire présente un outil d'aide à la décision pour la conception de systèmes manufacturiers cellulaires (SMC). L'outil se compose en trois phases. Pour la première phase, une heuristique de formation de cellules est démontrée selon sa particularité à pouvoir générer des scénarios de SMC reposant sur trois types de stratégies de configuration. La deuxième phase propose l'utilisation de la simulation pour combler le manque d'informations nécessaires à la conception que l'heuristique seule ne peut fournir. Pour cela, un modèle général de simulation spécialement conçu pour simuler différents scénarios est exposé et illustré. La dernière phase de l'outil présente une structure hiérarchique des critères quantitatifs et qualitatifs traités par la méthodologie du procédé d'analyse hiérarchique (AHP) qui permet au décideur, à l'aide d'une synthèse de pondération des critères, de choisir le meilleur des scénarios de système manufacturier générés dans les deux premières phases de la méthode de conception

Le conditionnement classique de la réponse sexuelle humaine masculine

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Uncertainty Propagation of a Multiscale Poromechanics-Hydration Model for Poroelastic Properties of Cement Paste at Early-Age

International audienceThe durability of concrete materials with regard to shrinkage and cracking phenomena depends on the evolution of the poroelastic properties of cement paste. The ability of engineers to control the uncertainty of the percolation threshold and the evolution of the elastic modulus, the Biot-Willis parameter and the skeleton Biot modulus is a keypoint of design practices to minimize the vulnerability of concrete structures at early-age. This article presents the uncertainty propagation and the sensitivity analysis of a multiscale poromechanics-hydration numerical model for cement pastes of water-to-cement ratio between 0.35 and 0.70. The model provides poroelastic properties required to model the behavior of partially saturated aging cement pastes (\emph{e.g.} autogenous shrinkage) and it predicts the percolation threshold and the undrained elastic modulus in good agreement with experimental data. The development of a stochastic metamodel using polynomial chaos expansion allows to propagate the uncertainty characteristic of the kinetic parameters of hydration, the quantitative cement phase composition, the elastic moduli of elementary material phases and the morphological parameters of the microstructure. The propagation does not magnify the uncertainty of the single poroelastic properties although, their correlation may amplify the variability of the estimates obtained from poroelastic state equations of cement paste. In order to reduce the uncertainty of the percolation threshold and of the poroelastic properties at early-age, it is recommanded to improve the accuracy of the apparent activation energy of calcium aluminate and, later on, of the elastic modulus of low density calcium-sillicate-hydrate

Proteomics reveals a switch in CDK1-associated proteins upon M-phase exit during the Xenopus laevis oocyte to embryo transition.

International audienceCyclin-dependent kinase 1 (CDK1) is a major M-phase kinase which requires the binding to a regulatory protein, Cyclin B, to be active. CDK1/Cyclin B complex is called M-phase promoting factor (MPF) for its key role in controlling both meiotic and mitotic M-phase of the cell cycle. CDK1 inactivation is necessary for oocyte activation and initiation of embryo development. This complex process requires both Cyclin B polyubiquitination and proteosomal degradation via the ubiquitin-conjugation pathway, followed by the dephosphorylation of the monomeric CDK1 on Thr161. Previous proteomic analyses revealed a number of CDK1-associated proteins in human HeLa cells. It is, however, unknown whether specific partners are involved in CDK1 inactivation upon M-phase exit. To better understand CDK1 regulation during MII-arrest and oocyte activation, we immunoprecipitated (IPed) CDK1 together with its associated proteins from M-phase-arrested and M-phase-exiting Xenopus laevis oocytes. A mass spectrometry (MS) analysis revealed a number of new putative CDK1 partners. Most importantly, the composition of the CDK1-associated complex changed rapidly during M-phase exit. Additionally, an analysis of CDK1 complexes precipitated with beads covered with p9 protein, a fission yeast suc1 homologue well known for its high affinity for CDKs, was performed to identify the most abundant proteins associated with CDK1. The screen was auto-validated by identification of: (i) two forms of CDK1: Cdc2A and B, (ii) a set of Cyclins B with clearly diminishing number of peptides identified upon M-phase exit, (iii) a number of known CDK1 substrates (e.g. peroxiredoxine) and partners (e.g. HSPA8, a member of the HSP70 family) both in IP and in p9 precipitated pellets. In IP samples we also identified chaperones, which can modulate CDK1 three-dimensional structure, as well as calcineurin, a protein necessary for successful oocyte activation. These results shed a new light on CDK1 regulation via a dynamic change in the composition of the protein complex upon M-phase exit and the oocyte to embryo transition

A Temporal Analysis of the Relation between Organisational Commitment and Work Motivation

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Dynamical Simulations of Magnetically Channeled Line-Driven Stellar Winds: II. The Effects of Field-Aligned Rotation

Building upon our previous MHD simulation study of magnetic channeling in radiatively driven stellar winds, we examine here the additional dynamical effects of stellar {\em rotation} in the (still) 2-D axisymmetric case of an aligned dipole surface field. In addition to the magnetic confinement parameter $\eta_{\ast}$ introduced in Paper I, we characterize the stellar rotation in terms of a parameter $W \equiv V_{\rm{rot}}/V_{\rm{orb}}$ (the ratio of the equatorial surface rotation speed to orbital speed), examining specifically models with moderately strong rotation $W =$ 0.25 and 0.5, and comparing these to analogous non-rotating cases. Defining the associated Alfv\'{e}n radius R_{\rm{A}} \approx \eta_{\ast}^{1/4} \Rstar and Kepler corotation radius R_{\rm{K}} \approx W^{-2/3} \Rstar, we find rotation effects are weak for models with $R_{\rm{A}} < R_{\rm{K}}$, but can be substantial and even dominant for models with R_{\rm{A}} \gtwig R_{\rm{K}}. In particular, by extending our simulations to magnetic confinement parameters (up to $\eta_{\ast} = 1000$) that are well above those ($\eta_{\ast} = 10$) considered in Paper I, we are able to study cases with $R_{\rm{A}} \gg R_{\rm{K}}$; we find that these do indeed show clear formation of the {\em rigid-body} disk predicted in previous analytic models, with however a rather complex, dynamic behavior characterized by both episodes of downward infall and outward breakout that limit the buildup of disk mass. Overall, the results provide an intriguing glimpse into the complex interplay between rotation and magnetic confinement, and form the basis for a full MHD description of the rigid-body disks expected in strongly magnetic Bp stars like $\sigma$ Ori E.Comment: 14 pp, visit this http://shayol.bartol.udel.edu/massivewiki-media/publications/rotation.pdf for full figure version of the paper. MNRAS, in pres

A dynamical magnetosphere model for periodic Halpha emission from the slowly rotating magnetic O star HD191612

The magnetic O-star HD191612 exhibits strongly variable, cyclic Balmer line emission on a 538-day period. We show here that its variable Halpha emission can be well reproduced by the rotational phase variation of synthetic spectra computed directly from full radiation magneto-hydrodynamical simulations of a magnetically confined wind. In slow rotators such as HD191612, wind material on closed magnetic field loops falls back to the star, but the transient suspension of material within the loops leads to a statistically overdense, low velocity region around the magnetic equator, causing the spectral variations. We contrast such "dynamical magnetospheres" (DMs) with the more steady-state "centrifugal magnetospheres" of stars with rapid rotation, and discuss the prospects of using this DM paradigm to explain periodic line emission from also other non-rapidly rotating magnetic massive stars.Comment: 5 pages, 5 figures, accepted for publication in MNRAS letter