Survival of water ice in Jupiter Trojans

Jupiter Trojans appear to be a key population of small bodies to study and test the models of the Solar System formation and evolution. Because understanding the evolution of Trojans can bring strong and unique constraints on the origins of our planetary system, a significant observational effort has been undertaken to unveil their physical characteristics. The data gathered so far are consistent with Trojans having volatile-rich interiors (possibly water ice) and volatile-poor surfaces (fine grained silicates). Since water ice is not thermodynamically stable against sublimation at the surface of an object located at ~5 AU, such layering seems consistent with past outgassing. In this work, we study the thermal history of Trojans after the formation of a dust mantle by possible past outgassing, so as to constrain the depth at which water ice could be stable. We find that it could have survived 100 m below the surface, even if Trojans orbited close to the Sun for ~10,000 years, as suggested by the most recent dynamical models. Water ice should be found ~10 m below the surface in most cases, and below 10 cm in the polar regions in some cases

Observation of elliptical rings in Type-I spontaneous parametric down-conversion

We investigate the transverse spatial profile of down-converted light produced by noncollinear, degenerate, Type-I spontaneous parametric down-conversion in two types of nonlinear crystals. We find that the pattern produced by one crystal, beta barium borate (BBO), produces a circular down-conversion pattern while the other crystal, bismuth triborate (BiBO) produces an elliptical pattern. We show this difference is due to the angle-independent refractive index experienced by the daughter photons in BBO, while they experience an angle-dependent refractive index in BiBO. We image the transverse spatial profile of the generated light to determine the eccentricity produced by each crystal and develop a model to explain our observation. Among other things, this model predicts that there is a wavelength for which the eccentricity from BiBO is nearly zero. Finally, we discuss how the elliptical ring pattern produced in BiBO potentially affects polarization entanglement for experimental setups that collect biphotons around the entire down-conversion ring. We show that the quality of polarization entanglement as measured by the overlap integral of the spectrum of the two rings, can remain high (>99.4%) around the entire ring at the expense of decreased biphoton rate

Médiation culturelle et résilience : La pratique du dit de vie en groupe interculturel

Cet article porte sur le rôle de médiation culturelle des ressources symboliques et narratives dans le processus de résilience qui est au coeur de l’expérience migratoire, notamment celle des migrations forcées. Il explique l’émergence du dit de vie et son processus d’élaboration à travers quatre exemples : le dit de vie de l’enfant comme une fraise ; le dit de vie de Kiroumi, l’enfant de nulle part ; le dit de vie de l’homme à la morsure de serpent ; le dit de vie de la profession et de la beauté, des forces de continuité dans la discontinuité. Enfin, il ouvre des pistes suggérant l’utilisation des dits de vie tirés de l’expérience des participants pour l’élaboration collective de dits de vie en groupes interculturels.This article focuses on the role of cultural mediation of symbolic and narrative resources in the resilience process which lies at the heart of the migration experience, including forced migrations. It explains the emergence of “ life tales ” (dits de vie) and their development process through four examples : the life tale of the child as a strawberry ; the life tale of Kiroumi, the child from nowhere ; the life tale of the man with the snake bite ; the life tale of the profession and beauty, of the forces of continuity and discontinuity. Finally, it explores the passage from the use of life tales based on participant’s experience for the collective development of life tales within intercultural groups

Determinants of the implementation of a new practice in hormonal contraception by Quebec nurses

In 2007, a task-shifting strategy through which a nurse, in collaboration with a community pharmacist, could start a healthy woman on hormonal contraception without a medical consultation was implemented in the province of Quebec. The purpose of this study was to identify factors associated with the 1) implementation of this new practice by nurses, 2) delay of implementation and 3) intensity of the practice. A validated questionnaire based on Rogers' theory of the diffusion of innovation was sent by postal mail or internet to all nurses that had successfully completed training in hormonal contraception since 2007, were registered at the College of nurses of Quebec and currently worked as nurses. The questionnaire was completed by 745 nurses between November 2011 and March 2012 for a response rate of 26.6%. Results show that implementation of this new nursing practice was more successful when nurses had a high degree of cosmopoliteness, they perceived the new practice as simple, they worked in youth clinics and if health organizations where they worked were open to innovation, had low centralized decision-making and organizational slack. Various attributes of innovation, diffusion networks and characteristics of the organizations also explained intensity of the new practice. The findings suggest new avenues to simplify and scale up this strategy for use in other health organizations. </jats:p