Alternatives to Risk Management Policies: View From the Country

Risk and Uncertainty,

Commentary: JWST near-infrared detector degradation— finding the problem, fixing the problem, and moving forward

The James Webb Space Telescope (JWST) is the successor to the Hubble Space Telescope. JWST will be an infrared-optimized telescope, with an approximately 6.5 m diameter primary mirror, that is located at the Sun-Earth L2 Lagrange point. Three of JWST’s four science instruments use Teledyne HgCdTe HAWAII-2RG (H2RG) near infrared detector arrays. During 2010, the JWST Project noticed that a few of its 5 μm cutoff H2RG detectors were degrading during room temperature storage, and NASA chartered a “Detector Degradation Failure Review Board” (DD-FRB) to investigate. The DD-FRB determined that the root cause was a design flaw that allowed indium to interdiffuse with the gold contacts and migrate into the HgCdTe detector layer. Fortunately, Teledyne already had an improved design that eliminated this degradation mechanism. During early 2012, the improved H2RG design was qualified for flight and JWST began making additional H2RGs. In this article, we present the two public DD-FRB “Executive Summaries” that: (1) determined the root cause of the detector degradation and (2) defined tests to determine whether the existing detectors are qualified for flight. We supplement these with a brief introduction to H2RG detector arrays, some recent measurements showing that the performance of the improved design meets JWST requirements, and a discussion of how the JWST Project is using cryogenic storage to retard the degradation rate of the existing flight spare H2RGs

Les contradictions fondamentales de l’école minoritaire

Dans des conditions sociales et démographiques très défavorables, nous demandons à l'école minoritaire de réussir là où la famille et la communauté éprouvent d'énormes difficultés. L'analyse reprend l'argumentation qui conduit à faire de l'école un agent de vitalité ethnolinguistique, examine l'environnement social qui délimite les véritables pouvoirs de l'école, et fait ressortir les contradictions fondamentales qui guettent l'école qui se donne comme mission le changement social. Devant l'ampleur de l'assimilation linguistique, la profondeur de l'acculturation et l'étendue de l'effritement des communautés canadiennes-françaises minoritaires, les défis de culturation et de communalisation de l'école sont démesurés par rapport aux moyens habituellement mis à sa disposition pour les relever.It is within very unfavourable social and demographic conditions that the minority school is required to succeed, even though the family and community have much difficulty in doing so. The analysis reexamines the reasoning that the role of the school is an agent of ethnolinguistic vitality, reexamines the social environment which establishes the real powers of the school, and finally demonstrates the fundamental contradictions that prevent the school from attaining social change objectives. The extent of linguistic assimilation, the impact of acculturation, and the reduction in French-Canadian minority communities are factors which provide too great a challenge in relation to the usual means provided for attaining socio-cultural objectives.Bajo condiciones sociales y demograficas muy desfavorables, exigimos que la escuela minoritaria tenga éxito en donde la familia y la comunidad sufren dificultades énormes. Este articulo hace un analisis retomando la argumentacion que conduce a hacer de la escuela un agente de vitalidad etnolingûïstica, examinando el entorno social que limita los verdaderos poderes de la escuela, y destacando las contradicciones fondamentales que acechan a la escuela que se da como mision el cambio social. Enfrentados con la amplitud de la asimilaciôn lingiiistica, la profundidad de la asimilaciôn cultural y la vastedad de la pulverizacion de las comunidades franco-canadienses minoritarias, los desafîos de culturacion y comunalizacion de la escuela son énormes en relacion con los medios normalmente puestos a su disposiciôn para enfrentrarlos.Auch dann, wenn die sozialen und demographischen Umstânde ungiinstig sind, wird von der Minderheitsschule verlangt, dass sie da Erfolg hat, wo Familie und Gemeinschaft énorme Schwierigkeiten haben. Der Au tor greift das Argument auf, nach welchem die Schule ein Motor der ethnolinguistischen Vitalitât ist, untersucht die sozialen Faktoren, die den Einfluss der Schule eindâmmen, und erortert die grundlegenden Widerspriiche, mit denen eine Schule konfrontiert wird, die soziale Verânderungen bewirken môchte. Die sprachliche Assimilation, die kulturelle Einverleibung und der gesellschaftliche Zerfall der frankokanadischen Minderheiten sind dermafien fortgeschritten, dass die Schule im Hinblick auf die geringen Mittel, iïber die sie herkômmlicherweise verfïigt, iiberfordert ist

Etude du ruissellement au Nord Cameroun : transfert de la parcelle au bassin versant

Les fonctions de production du ruissellement établies sur parcelles élémentaires, suivies en mode synchrone sous pluie simulée, et en diachrone sous pluies naturelles, ont été transposées à l'échelle du champ (3 000 m2) et du bassin versant (18,1 km2). L'étude sur le "Champ" a permis la décomposition de l'hydrogrammes global de crue en hydrogrammes partiels, représentatifs des deux aires participantes du bassin. Les volumes ruisselés sur chaque aire participante ont pu être calculés par les fonctions de production établies sous pluie simulée. (Résumé d'auteur

Short-range-order minerals and dominant accessory properties controlling P sorption in tropical tephra soils of the Cameroon volcanic line

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Voter discernment and candidate entry in pluralitarian election

The paper develops a sequential model of candidate entry into elections decided on the basis of plurality. We analyze the kinds of candidates who are most likely to enter elections and simulate several plausible myopic entry sequences under various assumptions about voter abilities to discern differences in candidate positions. In the cases examined, open elections for “important” positions attract the entry of more than two candidates. Moreover, myopic entry often generates electoral outcomes which depart from the median-mean outcomes of the conventional models. These results are consistent with the observed diversity of candidates in presidential and other significant primary elections which contrasts with many previous analyses of electoral entry