Heimdallr, Baldr, and Solarstein: designing the next generation of VLTI instruments in the Asgard suite.

High angular resolution imaging is an increasingly important capability in contemporary astrophysics. Of particular relevance to emerging fields such as the characterization of exoplanetary systems, imaging at the required spatial scales and contrast levels results in forbidding challenges in the correction of atmospheric phase errors, which in turn drives demanding requirements for precise wavefront sensing. Asgard is the next-generation instrument suite at the European Southern Observatory's Very Large Telescope Interferometer (VLTI), targeting advances in sensitivity, spectral resolution, and nulling interferometry. In this paper, we describe the requirements and designs of three core modules: Heimdallr, a beam combiner for fringe tracking, low order wavefront correction, and visibility science; Baldr, a Zernike wavefront sensor to correct high order atmospheric aberrations; and Solarstein, an alignment and calibration unit. In addition, we draw generalizable insights for designing such system and discuss integration plans.

Acceptability and Feasibility of Delivering Pentavalent Vaccines in a Compact, Prefilled, Autodisable Device in Vietnam and Senegal.

BACKGROUND: Prefilled syringes are the standard in developed countries but logistic and financial barriers prevent their widespread use in developing countries. The current study evaluated use of a compact, prefilled, autodisable device (CPAD) to deliver pentavalent vaccine by field actors in Senegal and Vietnam. METHODS: We conducted a logistic, programmatic, and anthropological study that included a) interviews of immunization staff at different health system levels and parents attending immunization sessions; b) observation of immunization sessions including CPAD use on oranges; and c) document review. RESULTS: Respondents perceived that the CPAD would improve safety by being non-reusable and preventing needle and vaccine exposure during preparation. Preparation was considered simple and may reduce immunization time for staff and caretakers. CPAD impact on cold storage requirements depended on the current pentavalent vaccine being used; in both countries, CPAD would reduce the weight and volume of materials and safety boxes thereby potentially improving outreach strategies and waste disposal. CPAD also would reduce stock outages by bundling vaccine and syringes and reduce wastage by using a non-breakable plastic presentation. Respondents also cited potential challenges including ability to distinguish between CPAD and other pharmaceuticals delivered via a similar mechanism (such as contraceptives), safety, and concerns related to design and ease of administration (such as activation, ease of delivery, and needle diameter and length). CONCLUSIONS: Compared to current pentavalent vaccine presentations in Vietnam and Senegal, CPAD technology will address some of the main barriers to vaccination, such as supply chain issues and safety concerns among health workers and families. Most of the challenges we identified can be addressed with health worker training, minor design modifications, and health messaging targeting parents and communities. Potentially the largest remaining barrier is the marginal increase in pentavalent cost--if any--from CPAD use, which we did not assess in our study.

La Sclérose En Plaques En Mauritanie

Introduction. Caracterisee par une demyelinisation de la substance blanche du systeme nerveux central; la Sclerose en plaques (SEP) se manifeste cliniquement par des tableaux encephaliques et/ ou medullaires subaigus. Il existerait un gradient Nord-Sud dans la repartition de la maladie. Les populations africaines (noires en particulier) et orientales seraient moins atteintes. La Mauritanie; par la diversite ethnique de sa population et sa situation geographique (trait d'union entre ces 2 regions) peut constituer un terrain interessant pour l'etude de cette maladie. De plus l'introduction de l'IRM dans notre pratique medicale depuis juillet 2005; constitue un atout pour le diagnostic de cette affection.Objectif. Presenter des observations de patients mauritaniens dont les tableaux cliniques et les explorations etaient en faveur d'une SEP. Methode. Nous avons selectionne 4 observations de malades hospitalises dans le Service de Neurologie du Centre Neuropsychiatrique de Nouakchott en Mauritanie; en 2005. Apres un examen clinique neurologique; ils avaient beneficie d'une exploration par IRM. Resultats. Le plus jeune de notre serie a 17 ans et le plus age 55 ans. Tous les patients etaient d'ethnie maure; trois etaient de race noire et un etait de race blanche. Tous ont presente des signes fortement evocateurs de SEP. Nous avons observe une forme d'emblee progressive; deux formes remittentes; et une premiere poussee chez une jeune fille. Les resultats de l'IRM cerebrale chez les 4 patients et de l'IRM medullaire chez trois patients ont montre des plaques de demyelinisation. Un seul patient pu avoir l'electrophorese des proteines du LCR qui a permis de montrer une distribution oligoclonale