Rational homotopy theory of automorphisms of manifolds

We study the rational homotopy types of classifying spaces of automorphism groups of smooth simply connected manifolds of dimension at least five. We give dg Lie algebra models for the homotopy automorphisms and the block diffeomorphisms of such manifolds. Moreover, we use these models to calculate the rational cohomology of the classifying spaces of the homotopy automorphisms and block diffeomorphisms of the manifold #^g S^d x S^d relative to an embedded disk as g tends to infinity. The answer is expressed in terms of stable cohomology of arithmetic groups and invariant Lie algebra cohomology. Through an extension of Kontsevich's work on graph complexes, we relate our results to the (unstable) homology of automorphisms of free groups with boundaries.Comment: 83 pages. Revision of v2 prompted by referee comments. Final version, to appear in Acta Mathematic

Research-based assessment affordances and constraints: Perceptions of physics faculty

To help faculty use research-based materials in a more significant way, we learn about their perceived needs and desires and use this information to suggest ways for the Physics Education Research community to address these needs. When research-based resources are well aligned with the perceived needs of faculty, faculty members will more readily take them up. We used phenomenographic interviews of ordinary physics faculty and department chairs to identify four families of issues that faculty have around research-based assessments (RBA). First, many faculty are interested in using RBAs but have practical needs around how to do so: how to find them, which ones there are, and how to administer them. They want help addressing these needs. Second, at the same time, many faculty think that RBAs are limited and don't measure many of the things they care about, or aren't applicable in their classes. They want assessments to measure skills, perceptions, and specific concepts. Third, many faculty want to turn to communities of other faculty and experts to help them interpret their assessment results and suggest other ways to do assessment. They want to norm their assessment results by comparing to others and interacting with faculty from other schools to learn about how they do assessment. Fourth, many faculty consider their courses in the broader contexts of accountability and their departments. They want help with assessment in these broader contexts. We also discuss how faculty members role in their department and type of institution influence their perceived wants and needs around assessment.Comment: submitted to Physical Review Special Topics - Physics Education Researc

Leadership drivers of organizational creativity: a path model of creative climate in a professional service firm

The purpose of this study was to explore how and under what conditions two different leadership roles are able to facilitate an organizational climate that supports creativity. The study was conducted in a leading professional service firm. The introduced hypotheses were tested by means of a structural equation model. Findings indicate that the leadership roles are conceptually different and that organizational structure is important for leaders’ ability to create a climate that supports creativity. The results also indicate that relational and change leadership behaviors are vital for leaders when creating a climate that supports creativity. Furthermore, both job autonomy and intrinsic motivation are found to be important dimensions for enhancing the creative climate

À la recherche d'un boson de Higgs chargé impliquant des signatures leptoniques à l'aide de l'expérience ATLAS.

This thesis presents searches for a charged Higgs boson (H+) in proton-proton collisions with center-of-mass energies of 7 TeV and 8 TeV, using data collected by the ATLAS experiment at the CERN Large Hadron Collider. Multiple search channels are used with a common characteristic of at least one charged lepton (electron or muon) that effectively reduces the multi-jet background and is used for efficient triggering.Charged Higgs bosons decaying to a tau lepton and a neutrino are searched for using final states with two charged leptons or one charged lepton and a hadronically decaying tau. A significant background originates from quark- and gluon-initiated jets that may be misidentified as hadronic tau decays. Methods to estimate this background are developed, including a largely data-driven matrix method. Signal processes with a charged Higgs boson mass below or above that of the top quark are considered. With the dataset collected at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3/fb, upper limits at 95% confidence level are placed on the branching fraction Br(t -≻ bH+)*Br(H+ -≻ τν) in the range 1.1-0.3% for charged Higgs boson masses between 80 GeV and 160 GeV, and on the top-quark associated charged Higgs boson production cross section in the range 0.53-0.04 pb for charged Higgs boson masses between 180 GeV and 1 TeV.Cette thèse présente la recherche d'un boson de Higgs chargé (H+) qui serait produit dans les collisions proton-proton à des énergies de 7 TeV et 8 TeV, en utilisant les données recueillies par l'expérience ATLAS au LHC (Large Hadron Collider). Plusieurs canaux de recherche sont utilisés, présentant la caractéristique commune de contenir au moins un lepton chargé (électron ou muon) énergétique, ce qui réduit efficacement le bruit de fond contenant des jets, tout en permettant un déclenchement efficace du détecteur.Ici le boson de Higgs chargé se désintègre en un lepton tau et un neutrino, ce qui conduit à des états finaux avec deux leptons chargés, ou bien un lepton chargé et un tau hadronique. Une source importante de taus mal identifiés provient de quarks et de gluons, par l'intermédiaire des jets hadroniques qu'ils initient. Plusieurs méthodes ont été développées pour estimer ce bruit de fond, l'une d'elles étant basée directement sur les données. Des processus avec des bosons de Higgs chargés dont la masse est soit en dessous soit au-dessus de celle du quark top sont considérés. Avec l'ensemble de données recueillies à une énergie de 8 TeV, correspondant à une luminosité intégrée de 20,3/fb, des limites avec un taux de confiance de 95% sont placées sur le rapport de branchement Br(t -≻ bH+)*Br(H+ -≻ τν) entre 1,1 et 0,3% pour des masses du boson de Higgs chargé entre 80 GeV et 160 GeV, et sur la section efficace de production du boson de Higgs chargé en association avec un quark top entre 0,53 et 0,04 pb, pour un boson de Higgs chargé ayant cette fois une masse comprise entre 180 GeV et 1 TeV