Pure motives with representable Chow groups

Let $k$ be an algebraically closed field. We show using Kahn's and Sujatha's theory of birational motives that a Chow motive over $k$ whose Chow groups are all representable belongs to the full and thick subcategory of motives generated by the twisted motives of curves. -- Motifs purs dont les groupes de Chow sont repr\'esentables. Soit $k$ un corps alg\'ebriquement clos. Nous prouvons, en nous servant de la th\'eorie des motifs birationnels d\'evelopp\'ee par Kahn et Sujatha, qu'un motif de Chow d\'efini sur $k$ dont les groupes de Chow sont tous repr\'esentables appartient \`a la sous-cat\'egorie pleine et \'epaisse des motifs engendr\'ee par les motifs de courbes tordus.Comment: 7 page

Homology and K-theory of the Bianchi groups

We reveal a correspondence between the homological torsion of the Bianchi groups and new geometric invariants, which are effectively computable thanks to their action on hyperbolic space. We use it to explicitly compute their integral group homology and equivariant $K$-homology. By the Baum/Connes conjecture, which holds for the Bianchi groups, we obtain the $K$-theory of their reduced $C^*$-algebras in terms of isomorphic images of the computed $K$-homology. We further find an application to Chen/Ruan orbifold cohomology. % {\it To cite this article: Alexander D. Rahm, C. R. Acad. Sci. Paris, Ser. I +++ (2011).

Some extremely amenable groups

A topological group $G$ is extremely amenable if every continuous action of $G$ on a compact space has a fixed point. Using the concentration of measure techniques developed by Gromov and Milman, we prove that the group of automorphisms of a Lebesgue space with a non-atomic measure is extremely amenable with the weak topology but not with the uniform one. Strengthening a de la Harpe's result, we show that a von Neumann algebra is approximately finite-dimensional if and only if its unitary group with the strong topology is the product of an extremely amenable group with a compact group.Comment: 7 pages, English with abridged French versio

Testing Invariance in Risk Taking: A Comparison Between Anglophone and Francophone Groups

This article investigates the measurement invariance of 3 related constructs across 2 groups sampled from Anglophone and Francophone adult populations. Multiple-group confirmatory factor analyses explored the factor structures of the Domain-Specific Risk-Taking (DOSPERT) Scale (Weber, Blais, & Betz, 2002), the Risk-Taking scale of the Jackson Personality Inventory (Jackson, 1994), and the Sensation-Seeking Scale (Zuckerman, 1980; 1994) both within and between the 2 groups of 172 Anglophone and 187 Francophone participants. The psychometric properties of the original and translated instruments are discussed, as is the meaningfulness of using these scales in these populations. Le présent article se penche sur l’invariance des mesures de trois construits corrélés pour deux groupes échantillonnés issus de populations adultes anglophones et francophones. Des analyses factorielles confirmatoires de groupes multiples ont été conduites sur les structures factorielles de l’échelle Domain-Specific Risk-Taking (DOSPERT) (Weber, Blais, et Betz, 2002), de l’échelle de prise de risque de l’inventaire de personnalité (Personality Inventory) de Jackson (Jackson, 1994), et de l’échelle de recherche de sensations (Sensation-Seeking Scale) de Zuckerman (Zuckerman, 1980; 1994) aussi bien à l’intérieur de deux groupes de 172 participants anglophones et de 187 participants francophones qu’entre ces deux mêmes groupes. Nous discutons des propriétés psychométriques des instruments originaux et traduits, de même que de la pertinence d’utiliser ces échelles au sein des populations en question.measurement invariance, psychometric scale, risk taking, sensation seeking, échelle psychométrique, invariance des mesures, prise de risques, recherche de sensations

Maximality of hyperspecial compact subgroups avoiding Bruhat-Tits theory

Let $k$ be a complete non-archimedean field (non trivially valued). Given a reductive $k$-group $G$, we prove that hyperspecial subgroups of $G(k)$ (i.e. those arising from reductive models of $G$) are maximal among bounded subgroups. The originality resides in the argument: it is inspired by the case of $\textrm{GL}_n$ and avoids all considerations on the Bruhat-Tits building of $G$.Comment: To appear at "Annales de l'Institut Fourier". This version avoids completely Berkovich geometr

La Responsabilité Sociétale de L'entreprise et Les Réactions des Parties Prenantes : le Cas de L'opérateur Téléphonique Mtn et des Utilisateurs de Téléphonie Mobile au Bénin

The purpose of this research is to understand the mechanisms by which the actions of corporate social responsibility can affect organizational commitment and organizational identification consumers. From an experiment performed with video support of social responsibility of the telephone operator MTN Benin, data were collected from a sample of judgment seven hundred and ten mobile phone users. The analysis shows that the consumer perception of the actions of social responsibility of the company affects their commitment and organizational identification. Socially responsible consumption appears as a moderating variable to put direct links days. However, the communication by the company on its "good deeds" does not seem to affect these relationships

Report on the support mision to the Coconut Agronomy & Farming System section of the Cocoa & Coconut Institute. Papua New Guinea, Stewart Research Station, Madang

Under 2003 programming by the French Embassy in Port Moresby, a multidisciplinary mission by an entomologist, Dr L. Ollivier, and an agronomist, Mr J. Ollivier from the CIRAD Tree Crops Department, was undertaken from 3 to 16 March 2004 at the Cocoa and Coconut Institute's Stewart Research Station in Madang Province, Papua New Guinea. The mission was used to take stock of the agronomy and farming systems activities being conducted by CCI at SRS, and in the COGENT participatory research network. Observations of the ongoing trials continued in 2003 and data were collected for analysis, the main results of which are presented in this report. Given budgetary restraints, it was not possible to fulfil some of the recommendations made at the time of the previous mission (fertilizer applications, leaf analyses). Some reorganization of the experimental design is proposed. In methodology terms, a presentation of the first results obtained using Olympe software to manage experimental data (also presented in the report) aroused a great deal of interest from our agronomy partners. Its use could be extended to processing data from on-farm participatory trials. The budget awarded by MOFA for 2004, which is in sharp decline, will not be enough to fund a CIRAD support mission in 2004 but could contribute towards our Papuan partners attending an international conference in Australia next August, where they would present work undertaken jointly with CIRAD. Restructuring of the research and extension services and their merger in 2003 to form the Cocoa and Coconut Institute (CC[) has led to a certain number of organizational changes: creation of a new organizational flow chart with 5 divisions (Cocoa Division, Coconut Division, Industry, Commercial and Corporate services). Mr. W. Akus, Coconut Division Head, expressed his desire to see collaboration with CIRAD continue in the form of regular support missions and training for CCI researchers at CIRAD. These links would make it possible to support CCI research activities in experimental data management and processing, draw up new research projects together, and disseminate the results obtained in scientific publications and articles

The congruence subgroup problem

This is a short survey of the progress on the congruence subgroup problem since the sixties when the first major results on the integral unimodular groups appeared. It is aimed at the non-specialists and avoids technical details.Comment: 10 page