Characterizing rings in terms of the extent of injectivity and projectivity of their modules

Given a ring R, we define its right i-profile (resp. right p-profile) to be the collection of injectivity domains (resp. projectivity domains) of its right R-modules. We study the lattice theoretic properties of these profiles and consider ways in which properties of the profiles may determine the structure of rings and viceversa. We show that the i-profile is isomorphic to an interval of the lattice of linear filters of right ideals of R, and is therefore modular and coatomic. In particular, we give a practical characterization of the i-profile of a right artinian ring. We show through an example that the p-profile is not necessarily a set, and also characterize the right p-profile of a right perfect ring. The study of rings in terms of their (i- or p-)profile was inspired by the study of rings with no (i- or p-) middle class, initiated in recent papers by Er, L\'opez-Permouth and S\"okmez, and by Holston, L\'opez-Permouth and Orhan-Ertas. In this paper, we obtain further results about these rings and we also use our results to provide a characterization of a special class of QF-rings in which the injectivity and projectivity domains of any module coincide.Comment: 19 pages, examples and propositions added. Title change

Probing Galaxy Dark Matter Haloes in COSMOS with Weak Lensing Flexion

Current theories of structure formation predict specific density profiles of galaxy dark matter haloes, and with weak gravitational lensing we can probe these profiles on several scales. On small scales, higher-order shape distortions known as flexion add significant detail to the weak lensing measurements. We present here the first detection of a galaxy-galaxy flexion signal in space-based data, obtained using a new Shapelets pipeline introduced here. We combine this higher-order lensing signal with shear to constrain the average density profile of the galaxy lenses in the Hubble Space Telescope COSMOS survey. We also show that light from nearby bright objects can significantly affect flexion measurements. After correcting for the influence of lens light, we show that the inclusion of flexion provides tighter constraints on density profiles than does shear alone. Finally we find an average density profile consistent with an isothermal sphere.Comment: 14 pages, 14 figures. Accepted for publication in MNRA

Le regroupement en flexion: un traitement antalgique non pharmacologique pour le prématuré : revue de la littérature

Depuis 1980, la douleur du nouveau-né prématuré n’est plus remise en question. Cependant, celui-ci subit de nombreux soins invasifs lors de son hospitalisation en néonatologie. La prise de sang représente notamment le quart des procédures administrées au prématuré. Dans un souci de confort et de sécurité de leur patient, les infirmières en néonatologie tentent de soulager le nouveau-né prématuré à l’aide d’interventions non pharmacologiques en combinaison avec les traitements médicamenteux

The process of institutionalization-deinstitutionalization and children’s psychological adjustment in Rwanda:: Parents matter

Negative effects of institutionalization and positive effects of deinstitutionalization on children’s wellbeing have been well documented. However, the majority of reports on institutional care rely on adult interviews and there is a wide disparity of results and methodologies in few result-oriented studies of deinstitutionalization outcome. In addition, though all over the world, especially in developed countries, many children in orphanage have parents; little is known about on the effect of having or not living biological parents and be institutionalized. The present thesis aims generally to investigate whether institutionalization negatively impacts the psychological adjustment of children. Specifically, this thesis aims at (1) exploring children’s perceptions on institutionalization process; (2) investigating the influence of biological parental living status on institutionalized children’s psychological adjustment; and (3) evaluating the effectiveness of deinstitutionalization as well as conditions for better psychological adjustment once children are deinstitutionalized. With a prospective longitudinal comparative design, focus group discussions and self-report questionnaires were used by the present thesis to collect respectively qualitative and quantitative data from 177 children aged 9 to 16 and their parents/primary caregivers divided in 6 registered orphanages and 5 primary schools in Rwanda. Grounded theory was used to analyze qualitative data whilst analysis of variance and multiple regression were used to analyze quantitative data. Outcome variables included externalizing and internalizing behavior, attachment and self-esteem. Taken together, our results show that institutionalization has a negative impact on children’s psychological adjustment. The most remarkable and unexpected finding is that Rwandan children living in institution have more impairment in psychopathological symptoms when they have living parents. They considered institutionalization as an orphanization process. Another remarkable finding is that the present thesis failed to prove the improvement of psychological adjustment due to de-institutionalization in all domains as expected. The improvement was reported in attachment while no change was observed in externalizing behavior or self-esteem after deinstitutionalization and worse, internalizing behavior worsened among de-institutionalized children. Family relationships and parenting involvement were reported to be the strongest predictors of children’s psychological adjustment in most of measured outcome variables. Unexpectedly, socioeconomic status, didn’t gain as much importance in that prediction. Contrariwise, adult’s perceived quality of life was a significant mediated predictor in children’s externalizing behavior and had a moderating effect in children’s internalizing behavior. This should be considered to develop and improve supportive specific interventions for children and considered when making the decision of placing or not a child with parents in an institution. Results suggest the intensification of identifying and addressing the behavioral problems as part of deinstitutionalization process focusing also on family characteristics to improve children’s psychological adjustment. Moreover, understanding the development of psychopathological problems during the process of institutionalization and de-institutionalization may be key to preventing high costs associated with these disorders across the life course