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

A practical model of convective dynamics for stellar evolution calculations

Turbulent motions in the interior of a star play an important role in its evolution, since they transport chemical species, thermal energy and angular momentum. Our overall goal is to construct a practical turbulent closure model for convective transport that can be used in a multi-dimensional stellar evolution calculation including the effects of rotation, shear and magnetic fields. Here, we focus on the first step of this task: capturing the well-known transition from radiative heat transport to turbulent convection with and without rotation, as well as the asymptotic relationship between turbulent and radiative transport in the limit of large Rayleigh number. We extend the closure model developed by Ogilvie (2003) and Garaud and Ogilvie (2005) to include heat transport and compare it with experimental results of Rayleigh-Benard convection.Comment: Conference proceeding for poster at conference "Unsolved problems in Stellar Physics

Chytridiomycosis related mortality in a midwife toad (Alytes obstetricans) in Belgium

Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis, contributes to amphibian declines worldwide. Recently, the fungus has shown to be widely distributed in Belgium and the Netherlands, although no clinical cases of the disease have been diagnosed yet. This case report describes the first case of mortality due to chytridiomycosis in Belgium in a wild population of midwife toads (Alytes obstetricans). The presence of clinical chytridiomycosis, combined with the relatively high prevalence of the fungus in Belgium, emphasizes the urgent need for a thorough study on the impact of infection on the native amphibian populations in Belgium

An experimental comparison of controllers for a vectored thrust, ducted fan engine

Experimental comparisons between four different control design methodologies are applied to a small vectored thrust engine. Each controller is applied to three trajectories of varying aggressiveness. The control strategies considered are LQR, ℋ∞, gain scheduling, and feedback linearization. The experiments show that gain scheduling is essential to achieving good performance. The strengths and weaknesses of each methodology are also examined

Do Female Northern Pintails, Anas acuta, Initiate Rapid Follicular Growth During Spring Migration?

We describe the reproductive status of female Northern Pintails (Anas acuta) staging on a flooded plain along the St. Lawrence River (Quebec, Canada) during the spring of 1997. Nine of the 27 female pintails we collected had ovarian follicles showing Rapid Follicular Growth (RFG). In RFG females, total blood calcium and ash mass increased with follicular development. They had greater muscle and bone mass, and higher blood calcium levels, compared to pre-RFG birds. However, carcass fat mass and sex hormone levels (estradiol and progesterone) did not differ between the two groups. Our results indicate that at least some Northern Pintails initiate egg formation processes prior to arrival at nesting areas, which is consistent with early nesting. The nutrients and energy required for this early egg formation must come from reserves stored during winter, foods consumed in staging areas, or both

Proposition d'une solution technologique pour le contrôle de la poussière provenant de la manutention de la pierre par convoyeur

L’objectif de cet essai est de recommander une solution optimale pour le contrôle de la poussière à l’usine de Graymont à Marbleton, au Québec, lors de la manutention de la pierre calcaire dans le secteur de concassage et de tamisage. La manutention se fait par convoyeurs à courroie et les points de transfert entre ceux-ci sont une source d’émission de poussière. La poussière est un polluant ayant plusieurs impacts notamment sur la santé respiratoire et sous forme de nuisances au voisinage. Elle entraîne également des impacts économiques importants, autant pour le producteur que pour le voisinage. C’est pourquoi il est nécessaire de contrôler les émissions de poussière, de manière à minimiser ces impacts. Une recherche et une analyse des solutions applicables ont été effectuées. Les critères d’efficacité, de maturité, de coût, d’impact sur les opérations et la maintenance et d’impact sur l’environnement et la santé et la sécurité ont été utilisés pour comparer entre elles les solutions. La solution la plus avantageuse consiste à installer des convoyeurs étanches aux points de transfert entre convoyeurs et des goulottes télescopiques dépoussiérées aux points de transfert vers les empilements. Cette solution l’emporte sur le dépoussiérage central typiquement utilisé en raison des coûts moindres, de son efficacité potentiellement supérieure et de sa passivité. Il reste néanmoins à tester la longueur appropriée de convoyeurs étanches à installer pour atteindre la performance de contrôle de poussière souhaitée

Functional Redundancy Patterns Reveal Non-Random Assembly Rules in a Species-Rich Marine Assemblage

The relationship between species and the functional diversity of assemblages is fundamental in ecology because it contains key information on functional redundancy, and functionally redundant ecosystems are thought to be more resilient, resistant and stable. However, this relationship is poorly understood and undocumented for species-rich coastal marine ecosystems. Here, we used underwater visual censuses to examine the patterns of functional redundancy for one of the most diverse vertebrate assemblages, the coral reef fishes of New Caledonia, South Pacific. First, we found that the relationship between functional and species diversity displayed a non-asymptotic power-shaped curve, implying that rare functions and species mainly occur in highly diverse assemblages. Second, we showed that the distribution of species amongst possible functions was significantly different from a random distribution up to a threshold of ∼90 species/transect. Redundancy patterns for each function further revealed that some functions displayed fast rates of increase in redundancy at low species diversity, whereas others were only becoming redundant past a certain threshold. This suggested non-random assembly rules and the existence of some primordial functions that would need to be fulfilled in priority so that coral reef fish assemblages can gain a basic ecological structure. Last, we found little effect of habitat on the shape of the functional-species diversity relationship and on the redundancy of functions, although habitat is known to largely determine assemblage characteristics such as species composition, biomass, and abundance. Our study shows that low functional redundancy is characteristic of this highly diverse fish assemblage, and, therefore, that even species-rich ecosystems such as coral reefs may be vulnerable to the removal of a few keystone species

Mathematical and physical ideas for climate science

The climate is a forced and dissipative nonlinear system featuring nontrivial dynamics on a vast range of spatial and temporal scales. The understanding of the climate's structural and multiscale properties is crucial for the provision of a unifying picture of its dynamics and for the implementation of accurate and efficient numerical models. We present some recent developments at the intersection between climate science, mathematics, and physics, which may prove fruitful in the direction of constructing a more comprehensive account of climate dynamics. We describe the Nambu formulation of fluid dynamics and the potential of such a theory for constructing sophisticated numerical models of geophysical fluids. Then, we focus on the statistical mechanics of quasi-equilibrium flows in a rotating environment, which seems crucial for constructing a robust theory of geophysical turbulence. We then discuss ideas and methods suited for approaching directly the nonequilibrium nature of the climate system. First, we describe some recent findings on the thermodynamics of climate, characterize its energy and entropy budgets, and discuss related methods for intercomparing climate models and for studying tipping points. These ideas can also create a common ground between geophysics and astrophysics by suggesting general tools for studying exoplanetary atmospheres. We conclude by focusing on nonequilibrium statistical mechanics, which allows for a unified framing of problems as different as the climate response to forcings, the effect of altering the boundary conditions or the coupling between geophysical flows, and the derivation of parametrizations for numerical models

0198: Global and regional echocardiographic strain to assess early phase of hypertrophic cardiomyopathy due to sarcomeric mutations

ObjectiveHypertrophic cardiomyopathy (HCM) is a genetic disease with delayed cardiac expression. Our objective was to characterize global and regional LV myocardial strain by two-dimensional imaging in sarcomeric HCM families and hypothesized that early systolic dysfunction, before hyper-trophic stage, may be diagnosed by this technique.Methods and resultsWe analyzed 81 adults: HCM patients with LV hypertrophy (LVH+, n=38), mutation carriers without LV hypertrophy (LVH/G+, n=20), and normal control subjects (n=23). We calculated global longitudinal strain (GLS), regional peak longitudinal strain and the Echo/TDI score (combination of 3 parameters about remodeling and pulse TDI). Age, sex ratio and body surface area were not significantly different between groups. Maximal 2D wall thickness of left ventricle was 10.1±1.6mm in LVH-/G+and not different from controls (9.9±1.2mm). We observed that LV GLS was not different in LVH-/G+as compared to controls (–21.6%±3.2 vs –23.5%±3.3) but was reduced in HCM patients (–15.3%±4.5) although a normal ejection fraction. Interestingly, regional peak longitudinal strain was similar in LVH-/G+and controls except antero-septo-basal segment strain that was decreased in LVH-/G+as compared to controls (–15.6%±7.2 vs –20.0%±3.9, p=0.025). A cut-off of –16% for abnormal strain of antero-septo-basal segment identified LVH-/G+subjects with a sensitivity of 47% and a specificity of 90%. The Echo/TDI score was different in LVH-/G+as compared to controls (p=0.0008) and sensitivity of previous defined cut-off was 83% for identification of LVH-/G+. All LVH-/G+subjects with abnormal regional strain, except one, had abnormal Echo/TDI score.ConclusionWe observed that regional longitudinal strain, but not global strain, was significantly reduced at early stage of HCM. This tool may be useful for clinical evaluation of relatives in daily practice, but does not provide significant additional information as compared to the Echo/TDI score