<p>This paper integrates and applies established findings from previous research into peer collaboration</p><p>to a realistic classroom situation in Swedish upper elementary school. The aim is to</p><p>survey the research literature and to replicate some of the potentially beneficial effects of peer</p><p>collaboration in an ‘ecologically valid’ setting, thus providing teachers with justifiable and</p><p>readily adoptable techniques. The study investigated the effect of collaborative problem solving</p><p>on students’ learning, where the conditions for collaboration were ‘optimised’ according</p><p>to previous findings with regard to ability, gender, task characteristics, and collaboration</p><p>strategy. Participants were 80 year 9 students (aged 15 years), who individually completed a</p><p>pre- and post-test comprising moderately complex diagram interpretation tasks. During the</p><p>experimental phase, students completed a similar task, either individually or collaboratively.</p><p>Students who collaborated were assigned to mixed-gender pairs using a ‘weak-strong’ heuristic,</p><p>based on pre-test results. Results indicated that lower-ability students collaborating with</p><p>higher-ability peers improved from pre-test to post-test, while higher-ability students regressed</p><p>significantly. Students working collaboratively did not perform significantly better</p><p>than did students working alone. Discussion extends beyond these findings to implications of</p><p>research on peer collaboration for teachers and students’ learning.</p>

In this paper we find irreducible characters of G=SL(k,Z/p^nZ) where n >= 2, k=2,3 and, p is an odd prime. In the case k=2 we give a construction for every irreducible character of G without calculating the character values. Our method is based on finding a normal subgroup of G and applying Clifford theory. / Mathematics

Thèse--Universit́e de Paris. / A digital reproduction made from a copy held by Cornel University is available from the Cornell University Library's Historical Mathematics Monographs Web site.

Thesis (D. Th.)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Thesis (Ph. D.)--Oregon State University, 1980. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Cette thèse est consacrée à l'étude du groupe d'automorphismes de groupes agissant sur des arbres d'une part, et du rang des groupes de Coxeter d'autre part. Via la théorie de Bass-Serre, un groupe agissant sur un arbre est doté d'une structure algébrique particulière, généralisant produits amalgamés et extensions HNN. Le groupe est en fait déterminé par certaines données combinatoires découlant de cette action, appelées graphes de groupes. Un cas particulier de cette situation est celle d'un produit libre. Une présentation du groupe d'automorphisme d'un produit libre d'un nombre fini de groupes librement indécomposables en termes de présentation des facteurs et de leurs groupes d'automorphismes a été donnée par Fouxe-Rabinovich. Il découle de son travail que si les facteurs et leurs groupes d'automorphismes sont de présentation finie, alors le groupe d'automorphisme du produit libre est de présentation finie. Une première partie de cette thèse donne une nouvelle preuve de ce résultat, se basant sur le langage des actions de groupes sur les arbres. Un groupe accessible est un groupe de type fini déterminé par un graphe de groupe fini dont les groupes d'arêtes sont finis et les groupes de sommets ont au plus un bout, c'est-à-dire qu'ils ne se décomposent pas en produit amalgamé ni en extension HNN sur un groupe fini. L'étude du groupe d'automorphisme d'un groupe accessible est ramenée à l'étude de groupes d'automorphismes de produits libres, de groupes de twists de Dehn et de groupes d'automorphismes relatifs des groupes de sommets. En particulier, on déduit un critère naturel pour que le groupe d'automorphismes d'un groupe accessible soit de présentation finie, et on donne une caractérisation des groupes accessibles dont le groupe d'automorphisme externe est fini. Appliqués aux groupes hyperboliques de Gromov, ces résultats permettent d'affirmer que le groupe d'automorphismes d'un groupe hyperbolique est de présentation finie, et donnent une caractérisation précise des groupes hyperboliques dont le groupe d'automorphisme externe est fini. Enfin, on étudie le rang des groupes de Coxeter, c'est-à-dire le cardinal minimal d'un ensemble générateur pour un groupe de Coxeter donné. Plus précisément, on montre que si les composantes de la matrice de Coxeter déterminant un groupe de Coxeter sont suffisamment grandes, alors l'ensemble générateur standard est de cardinal minimal parmi tous les ensembles générateurs.

La recherche a montré que les enseignants se réfèrent à un sous-ensemble délèves, le steering group, pour piloter leur enseignement (planification y comprise). Alors que les résultats de certains auteurs montrent que lenseignement est calibré sur les faibles, dautres études indiquent que ce sont les forts qui sont pris en compte. Cette thèse de doctorat rassemble sept articles qui se penchent sur le phénomène de steering group. Les sept articles sont organisés en trois parties. La première combine deux articles de revue de littérature portant sur les processus de pensée des enseignants lors de la planification et de linteraction en classe. La problématique du steering group y est située dans les processus de gestion de dilemmes de la part des enseignants. Après une partie plus méthodologique, une partie empirique rassemble quatre articles portant sur ce même phénomène. La pertinence de lhypothèse de la mise en dilemmes est quantitativement vérifiée (150 enseignants primaires) : les enseignants se posent-ils la question des élèves sur qui centrer lenseignement dans le cadre de la gestion des programmes officiels : les forts ou les faibles ? Ensuite, la manière dont les enseignants utilisent leur(s) steering group(s) est analysée dans des études qualitatives (10 enseignants primaires). Les résultats des différentes études montrent, dune part, que lhypothèse de la mise en dilemme peut être conservée et, dautre part, que la gestion de la classe va au-delà dune affaire de forts ou de faibles. Les enseignants centrent leurs interventions sur les forts en appliquant des stratégies de compensation réservées aux faibles et inversement. Enfin, les sept articles sont mis en perspectives dans une discussion qui propose diverses ouvertures de recherches portant sur lanalyse des processus décisionnels des enseignants ainsi que sur le développement et lévolution de leurs croyances et connaissances psychopédagogiques. / Research has shown that teachers refer to a subgroup of pupils, named steering group, to pace their teaching (planning thought processes included). While some researchers have shown that teachers refer to the low performance pupils, some other have shown that the high performers are taken into account. Seven articles focussed on the steering group phenomenon are regrouped in this doctoral dissertation. These seven articles avec organised in three main areas. The first area is theoretical and presents two literature reviews concerning the teacher thought processes during planning and teaching interaction in the classroom. The steering group phenomenon is situated in the thought processes teachers are engaged when they manage teaching dilemmas. After an article dealing with methodological issues, an empirical area is presenting four articles focussed on the steering group phenomenon. The relevance of the dilemma management by teachers is quantitatively analysed (150 elementary teachers): are teachers concerned with the question on which pupils to focus instruction regarding to progression in the official curriculum: low or high performers? The manner teacher use their steering group(s) is then analysed in some qualitative studies (10 elementary teachers). Results show, on the one hand, that the dilemma management hypothesis could be maintained and, on the other hand, that classroom management goes beyond focussing on the high or low performers. Teachers pace their instruction for the high performers, while implementing compensation strategies for the low performers, and inversely. Finally, the seven articles are discussed to suggest different research perspectives concerning teachers decision making processes and the development and evolution of their knowledge and beliefs.

This paper integrates and applies established findings from previous research into peer collaboration to a realistic classroom situation in Swedish upper elementary school. The aim is to survey the research literature and to replicate some of the potentially beneficial effects of peer collaboration in an ‘ecologically valid’ setting, thus providing teachers with justifiable and readily adoptable techniques. The study investigated the effect of collaborative problem solving on students’ learning, where the conditions for collaboration were ‘optimised’ according to previous findings with regard to ability, gender, task characteristics, and collaboration strategy. Participants were 80 year 9 students (aged 15 years), who individually completed a pre- and post-test comprising moderately complex diagram interpretation tasks. During the experimental phase, students completed a similar task, either individually or collaboratively. Students who collaborated were assigned to mixed-gender pairs using a ‘weak-strong’ heuristic, based on pre-test results. Results indicated that lower-ability students collaborating with higher-ability peers improved from pre-test to post-test, while higher-ability students regressed significantly. Students working collaboratively did not perform significantly better than did students working alone. Discussion extends beyond these findings to implications of research on peer collaboration for teachers and students’ learning.

In this work we study the space of group homomorphisms Hom(Γ,G) from a geometric and simplicial point of view. The case in which the source group is a free abelian group of rank n is studied in more detail since this space can be identified with the space of commuting n-tuples of elements from G. This latter case is of particular interest when the target is a Lie group. The simplicial approach allows us to to construct a family of spaces that filters the classifying space of a group by filtering group theoretical information of the given group. Namely, we use the lower central series of free groups to construct a family of simplicial subspaces of the bar construction of the classifying space of a group. The first layer of this filtration is studied in more detail for transitively commutative (TC) groups.

Ostracism, the process of socially ignoring and excluding certain people, has attracted attention in recent years. Most studies have looked at full ostracism, in other words, when everyone in a group ignores a person. However, in real life, people are usually only partially ostracized – excluded by some members of a group and not by others. The present study is one of the first to provide an in-depth examination of reactions when different forms of partial ostracism occur in a group. It looks at partial ostracism in a field study and an experimental study. In the field study I proposed that because targets of partial ostracism receive mixed signals from their group, it is easier for them to interpret ostracism as an external event rather than internal; whereas in full ostracism because all the signs received by the target are the same, the target cannot interpret the act of ostracism in different ways. The results of the field study indicate that partial ostracism is not only more common than full ostracism at work, but targets of partial ostracism also make fewer internal attributions than do targets of full ostracism. The experimental study examined two dimensions of partial ostracism: activity exclusion (AE) and people exclusion (PE). Results indicate that as AE increases, i.e. targets are excluded from more activities, targets make fewer internal attributions, feel more threats to their basic needs (mediated by internal attributions), and have more desire to help others. As PE increases, targets feel more threats to their needs and put less effort into group tasks. Comparing AE and PE simultaneously, AE makes a difference in targets’ well-being while PE affects targets’ efforts in group tasks