Léo Strauss: art d'écrire, politique, philosophie

L'ouvrage examine la pensée de Léo Strauss (1899-1973) et étudie à partir d'elle les stratégies d'exposition et de dissimulation de la philosophie. Les études qu'il réunit mesurent la portée de l'hypothèse d'un "art d'écrire oublié" et examinent la fécondité et les limites de la conception straussienne de l'écriture philosophique.

Usages étudiants des outils informatiques liés à Smiley EE

Ce projet de recherche s’inscrit dans un contexte institutionnel particulier. Depuis 2011, l’ULB rénove ses différentes plateformes informatiques afin d’améliorer les outils et services rendus à la communauté étudiante. Portant le nom de « SMILEY », ce grand projet gère entre autres les outils MonULB, GeHol, Web mail, U.V. etc. et a pour objectif une gestion plus simple, plus efficace et plus flexible de l’Université. Étant donné la complexité initiale du système de gestion de l’ULB, la mise en place du projet Smiley ne s’est pas faite sans difficultés. Divers bugs et imprévus ont été et sont encore rencontrés. Dans ce cadre, les autorités de l’ULB ont décidé de créer un observatoire pour mener des recherches sur les usages étudiants des outils informatiques liés à SMILEY EE (pour Études et Étudiants) afin d’améliorer l’acceptation des outils concernés. Au cours de ces recherches, différentes variables en lien avec l’utilisabilité et l’expérience utilisateur seront envisagées :connaissance du web, connaissance des TIC, sentiment d’efficacité personnel, perception de l’utilité et de la facilité d’utilisation des interfaces, stratégies de recherche d’information utilisées, sentiment d’autonomie t de contrôle, satisfaction cognitive et affective, identification à l’institution… Dès lors, les objectifs sont ;outre l’étude des déterminants de l’acceptation des Tic étudiants, de collecter l’avis des utilisateurs concernés, de fournir des recommandations, d’accompagner la mise en œuvre des améliorations et d’anticiper les besoins/attentes futures en matière de TIC à l’université.Pour cela, les méthodologies employées seront qualitatives et quantitatives. Des groupes de discussions exploratoire seront organisés afin d’identifier plus précisément les facteurs de satisfaction et d’insatisfaction, et des tests d’utilisabilités seront élaborés pour déterminer in situ les difficultés rencontrées. Des questionnaires en ligne seront aussi diffusés afin de déterminer le rôle des variables susmentionnées auprès d’un échantillon représentatif de la communauté estudiantine. L’ensemble des résultats permettra alors de guider des actions concrètes sur les outils étudiés.

No self-interaction for two-column massless fields

We investigate the problem of introducing consistent self-couplings in free theories for mixed tensor gauge fields whose symmetry properties are characterized by Young diagrams made of two columns of arbitrary (but different) lengths. We prove that, in flat space, these theories admit no local, Poincaré-invariant, smooth, selfinteracting deformation with at most two derivatives in the Lagrangian. Relaxing the derivative and Lorentz-invariance assumptions, there still is no deformation that modifies the gauge algebra, and in most cases no deformation that alters the gauge transformations. Our approach is based on a Becchi-Rouet-Stora-iyutin (BRST) -cohomology deformation procedure. © 2005 American Institute of Physics.

Long-distance quantum communication just around the corner?

info:eu-repo/semantics/published

On the problems of object restoration and image extrapolation in optics

In this paper we consider the problems of object restoration and image extrapolation, according to the regularization theory of improperly posed problems. In order to take into account the stochastic nature of the noise and to introduce the main concepts of information theory, great attention is devoted to the probabilistic methods of regularization. The kind of the restored continuity is investigated in detail; in particular we prove that, while the image extrapolation presents a Hölder type stability, the object restoration has only a logarithmic continuity. © 1979 American Institute of Physics.

Extraction of polydispersity information from photon correlation data

Photon correlation spectroscopy (PCS) is a light-scattering technique for particle size diagnosis. It has been used mainly in the investigation of hydrosol particles since it is based on the measurement of the correlation function of the light scattered from the Brownian motion of suspended particles. Recently this technique also proved useful for studying soot particles in flames and similar aerosol systems. In the case of a polydispersed system the problem of recovering the particle size distribution can be reduced to the problem of inverting the Laplace transform. In this paper we review several methods introduced by the authors for the solution of this problem. We present some numerical results and we discuss the resolution limits characterizing the reconstruction of the size distributions. © 1989.

Project Manager

Le projet de construction au XXIe siècle :nouveaux acteurs, nouvelles responsabilités. L’apparition de nouveaux intervenants dans les projets de contruction bouleverse le schéma classique Maître d’ouvrage – Architecte – Entrepreneur. Parmi ceux-ci, le Project Manager occupe une place de premier rang, dès lors qu’il interviendra bien souvent dès l’entame du projet et jusqu’à complétion de celui-ci. L’ouvrage offre une première analyse complète de sa situation juridique, en mêlant littérature juridique (belge, française et américaine) et pratique de terrain. Envisagé ici à travers le prisme de sa relation contractuelle avec le Maître d’ouvrage, le Project manager reçoit une définition légale d’où sont déduits les éléments essentiels de se son contrat. Son statut, ses missions ainsi que ses responsabilités sont identiés précisément et articulés harmonieusement avec ceux d’autre professionnels (arhitectes et entrepreneurs). Spécialement sur la question des reponsabilités, l’ouvrage démontre que certains cas de responsabilité traditionnellement imputés à l’un de ces autres acteurs pourront être imputés au Project Manager, allant dans le sens d’un régime unifié de responsabilité pour l’ensemble de ces acteurs. L’ouvrage s’enrichit encore d’un modèle contractuel de base et d’une bibliographie.Incontestablement, l’ouvrage vient combler un vide doctrinal et constituera un guide essentiel, tant pour les Maîtres d’ouvrage que pour les Project Manager.

Catalyse et pot catalytique

Dans la lignée des précédents fascicules de chimie, ce dossier est consacré à la catalyse :qu'est-ce que la catalyse ?Exemples de réactions catalysées, le pot catalytique, quel carburant choisir ?Finie la pollution automobile ?La pile à combustible.

Supercontinuum generation in air-silica microstructured fibers with nanosecond and femtosecond pulse pumping

We study the generation of supercontinua in air-silica microstructured fibers by both nanosecond and femtosecond pulse excitation. In the nanosecond experiments, a 300-nm broadband visible continuum was generated in a 1.8-m length of fiber pumped at 532 nm by 0.8-ns pulses from a frequency-doubled passively Q-switched Nd:YAG microchip laser. At this wavelength, the dominant mode excited under the conditions of continuum generation is the LP 11 mode, and, with nanosecond pumping, self-phase modulation is negligible and the continuum generation is dominated by the interplay of Raman and parametric effects. The spectral extent of the continuum is well explained by calculations of the parametric gain curves for four-wave mixing about the zero-dispersion wavelength of the LP11 mode. In the femtosecond experiments, an 800-nm broad-band visible and near-infrared continuum has been generated in a 1-m length of fiber pumped at 780 nm by 100-fs pulses from a Kerr-lens model-locked Ti:sapphire laser. At this wavelength, excitation and continuum generation occur in the LP01 mode, and the spectral width of the observed continuum is shown to be consistent with the phase-matching bandwidth for parametric processes calculated for this fiber mode. In addition, numerical simulations based on an extended nonlinear Schrödinger equation were used to model supercontinuum generation in the femtosecond regime, with the simulation results reproducing the major features of the experimentally observed spectrum. © 2002 Optical Society of America.

Control estructural de agrietamientos poligonales en la Pedriza del Manzanares (Madrid)

Los agrietamientos poligonales representan una forma común de modelado granítico cuyo origen y evolución continúa en fase de estudio, no existiendo una sistematización de estas estructuras diversas. Algunos autores explican su origen por procesos geodinámicos internos, relacionándolo con movimientos de planos de fractura en estados tardíos de consolidación magmática. Otros autores atribuyen su formación y desarrollo a factores externos relacionados con el régimen climático. La gran variedad de agrietamientos poligonales requiere la utilización de un número mayor de variables para definir los distintos orígenes, y las posibles interrelaciones entre los factores externos e internos, así como para explicar la evolución de dichas estructuras y avanzar en la clasificación de los patrones concretos. Este trabajo pretende contribuir a sistematizar los mecanismos que intervienen en el desarrollo de agrietamientos poligonales. Para ello se estudian únicamente agrietamientos poligonales formados sobre planos de fractura verticales o subverticales. En particular se establecen relaciones entre la presencia de agrietamientos poligonales y la red de fracturación, la altura de aparición, la orientación e inclinación de la pared, la morfología de las placas y la profundidad de incisión de las grietas perimetrales. Por otra parte, establece relaciones entre procesos geodinámicos internos y procesos de meteorización externos.

Regularization and Bang-bang conjugate times in optimal control

Consideramos o problema de controlo óptimo de tempo mínimo para sistemas de controlo mono-entrada e controlo afim num espaço de dimensão finita com condições inicial e final fixas, onde o controlo escalar toma valores num intervalo fechado. Quando aplicamos o método de tiro a este problema, vários obstáculos podem surgir uma vez que a função de tiro não é diferenciável quando o controlo é bang-bang. No caso bang-bang os tempos conjugados são teoricamente bem definidos para este tipo de sistemas de controlo, contudo os algoritmos computacionais directos disponíveis são de difícil aplicação. Por outro lado, no caso suave o conceito teórico e prático de tempos conjugados é bem conhecido, e ferramentas computacionais eficazes estão disponíveis. Propomos um procedimento de regularização para o qual as soluções do problema de tempo mínimo correspondente dependem de um parâmetro real positivo suficientemente pequeno e são definidas por funções suaves em relação à variável tempo, facilitando a aplicação do método de tiro simples. Provamos, sob hipóteses convenientes, a convergência forte das soluções do problema regularizado para a solução do problema inicial, quando o parâmetro real tende para zero. A determinação de tempos conjugados das trajectórias localmente óptimas do problema regularizado enquadra-se na teoria suave conhecida. Provamos, sob hipóteses adequadas, a convergência do primeiro tempo conjugado do problema regularizado para o primeiro tempo conjugado do problema inicial bang-bang, quando o parâmetro real tende para zero. Consequentemente, obtemos um algoritmo eficiente para a computação de tempos conjugados no caso bang-bang.

As políticas educativas e o impacto no trabalho dos professores

A presente investigação, que tem os professores como figura central, constitui um trabalho de problematização sobre o impacto que as políticas educativas dos últimos dez anos têm tido na (re)definição da profissão e do trabalho docente. Num tempo marcado por rápidas e profundas mudanças económicas, políticas, sociais e culturais, os professores defrontam-se com novas situações, novos saberes e novas conceções pedagógicas. Por este motivo, impôs-se a preocupação académica de compreender o modo como os professores encaram a existência de novas exigências e dos desafios constantes com que são confrontados, lidam com eles, definem estratégias e finalidades de ação, enunciando os seus compromissos profissionais, os seus saberes e os modos de ser e de estar na profissão. Assim, a reflexão em torno das políticas educativas e do trabalho docente adquire uma importância inquestionável como uma problemática essencial para se compreender os sentidos da escola, das suas finalidades educativas e da ação dos professores. A investigação permitiu concluir que o Estado, agora avaliador, tende a abandonar o ideal de igualdades de oportunidades para o objetivo de igualdade dos resultados, onde sobressai o desenvolvimento de uma política educativa assente na lógica da eficácia e da competição. Concluiu-se, ainda, que a intensificação e a complexificação das tarefas que incumbem aos professores e o aumento exponencial de dispositivos burocráticos no exercício da profissão configuram a emergência de novas formas de governo e de controlo da profissão, contribuindo também para a sua desqualificação. Neste contexto, as relações profissionais que os docentes estabelecem entre si, o recentrar da escola na aprendizagem dos alunos e o conhecimento profissional dos professores são encarados pela autora como cruciais para a configuração de uma nova profissionalidade docente e para o desenvolvimento de perspetivas educacionais progressistas e emancipatórias. Foi intencional a opção por uma metodologia qualitativa, apoiada num paradigma que valoriza as vozes dos indivíduos que falam, quer o sujeito que, na sua qualidade de investigador, ouve ou lê a fala do narrador e a interpreta num encontro de subjetividades. Elegeu-se como estratégias de recolha de informação as entrevistas semiestruturadas e a aplicação de inquérito por questionário, na tentativa de recolher toda a riqueza subjetiva de quem neles se diz e de ultrapassar a velha aporia entre métodos quantitativos e qualitativos.

Nanosensor for assessing the risk of a cardiovascular disease

The incidence of cardiovascular diseases (CVD) has been increasing according to the European and global statistics. Thus, the development of new analytical devices, such as biosensors for assessing the risk of CVD could become a valuable approach for the improvement of healthcare service. In latest years, the nanotechnology has provided new materials with improved electronic properties which have an important contribution in the transduction mechanism of biosensors. Thus, in this thesis, biosensors based on field effect transistors with single-walled carbon nanotubes (NTFET) were developed for the detection of C-reactive protein (CRP) in clinical samples, that is, blood serum and saliva from a group of control patients and a group of CVD risk patients. CRP is an acute-phase protein, which is commonly known as the best validated biomarker for the assessment of CVD, the single-walled carbon nanotubes (SWCNT) were applied as transduction components, and the immunoreaction (interaction between the CRP antigen and the antibodies specific to CRP) was used as the mechanism of molecular recognition for the label-free detection of CRP. After the microfabrication of field effect transistors (FET), the screening of the most important variables for the dispersion of SWCNT, the assemblage of NTFET, and their application on standard solutions of CRP, it was found that NTFET respond accurately to CRP both in saliva and in serum samples, since similar CRP levels were found with the NTFET and the traditional methodology (ELISA technique). On the other hand, a strong correlation between salivary and serum CRP was found with NTFET, which means that saliva could be used, based on non-invasive sampling, as an alternative fluid to blood serum. It was also shown that NTFET could discriminate control patients from CVD risk patients, allowing the determination of a cut-off value for salivary CRP of 1900 ng L-1, which corresponds to the well established cut-off of 3 mg L-1 for CRP in serum, constituting an important finding for the possible establishment of a new range of CRP levels based on saliva. According to the data provided from the volunteer patients regarding their lipoprotein profile and lifestyle factors, it was concluded that the control and the CVD risk patients could be separated taking into account the various risk factors established in literature as strong contributors for developing a CVD, such as triglycerides, serum CRP, total cholesterol, LDL cholesterol, body mass index, Framingham risk score, hypertension, dyslipidemia, and diabetes mellitus. Thus, this work could provide an additional contribution to the understanding of the association of biomarkers levels in serum and saliva samples, and above all, cost-effective, rapid, label-free, and disposable NTFET were developed, based on a noninvasive sampling, for the assessment of CVD risk, thus constituting a potential point-of-care technology.

Formation en intégration scolaire impact sur les connaissances d'une enseignante et sur le fonctiononement social d'élèves intégrés et ordinaires

La présente recherche a pour but d'évaluer l'impact d'une formation en intégration scolaire sur une enseignante et ses élèves.La formation en question est un programme universitaire de deuxième cycle dispensé à l'Université de Sherbrooke. Le projet actuel vise à mesurer les retombées des deux premières activités de cette formation, c'est-à-dire celles visant la problématique de l'intégration scolaire et la connaissance de la clientèle. Pour ce faire, l'estime de soi, le climat de classe et le fonctionnement social des élèves d'un groupe expérimental sont comparés à ceux d'un groupe contrôle dont l'enseignante n'a pas suivi la formation. Les données sont collectées à l'aide de questionnaires, d'une grille d'observation et d'un sociogramme. Afin de vérifier s'il y a un changement au niveau de la connaissance des clientèles en difficulté, les deux enseignantes remplissent un questionnaire au début et à la fin de la deuxième activité de formation. Les différentes mesures adressées aux élèves sont collectées après l'activité de formation en question. (Résumé abrégé par UMI.)