L'apport du réaffûtage à la variabilité morphométrique des pointes de projectile aurignaciennes en bois de cervidé

Ce projet combine l’archéologie expérimentale, l’analyse morphométrique et la comparaison des résultats à l’assemblage archéologique de l’Abri Cellier (Dordogne, France) (N = 12) dans le but de quantifier l’apport du réaffûtage à la variabilité des formes et des dimensions des pointes de projectile aurignaciennes en bois de cervidé. La relecture morphofonctionnelle de la série expérimentale de Knecht (N = 79) couplée à une reproduction expérimentale récente (N = 9) démontre que la nature des dommages infligés au fût des pointes dépend (1) de la force du tir, (2) de la nature de la cible impactée et, (3) des propriétés biomécaniques du matériau employé. Pour sa part, le réaffûtage dépend (1) de l’expérience du réaffûteur et, (2) de la séquence technique employée. Ce comportement est standardisé et demeure indépendant du type de pointe de même que du type de dommage du fût. Les changements morphométriques associés à ce comportement se résument (1) à un déplacement progressif de l’épaule de la base vers le fût de la pointe, (2) à une tendance à l’accroissement de l’angle du fût et, (3) à une localisation des traces de réaffûtage sur le tiers distal de la partie distale de la pointe. Puisque l’utilisation et le réaffûtage sont deux processus impossible à départager sur les artefacts, nous proposons l’adoption d’une mesure, le ratio proximo-distal (RP/D) afin de traduire l’intensité de ces processus convergents et faciliter la comparaison entre les assemblages archéologiques.

Multi-scale systems analysis of plant development : beyond cellular signaling and tissue morphodynamics

Les plantes sont essentielles pour les sociétés humaines. Notre alimentation quotidienne, les matériaux de constructions et les sources énergétiques dérivent de la biomasse végétale. En revanche, la compréhension des multiples aspects développementaux des plantes est encore peu exploitée et représente un sujet de recherche majeur pour la science. L'émergence des technologies à haut débit pour le séquençage de génome à grande échelle ou l'imagerie de haute résolution permet à présent de produire des quantités énormes d'information. L'analyse informatique est une façon d'intégrer ces données et de réduire la complexité apparente vers une échelle d'abstraction appropriée, dont la finalité est de fournir des perspectives de recherches ciblées. Ceci représente la raison première de cette thèse. En d'autres termes, nous appliquons des méthodes descriptives et prédictives combinées à des simulations numériques afin d'apporter des solutions originales à des problèmes relatifs à la morphogénèse à l'échelle de la cellule et de l'organe. Nous nous sommes fixés parmi les objectifs principaux de cette thèse d'élucider de quelle manière l'interaction croisée des phytohormones auxine et brassinosteroïdes (BRs) détermine la croissance de la cellule dans la racine du méristème apical d'Arabidopsis thaliana, l'organisme modèle de référence pour les études moléculaires en plantes. Pour reconstruire le réseau de signalement cellulaire, nous avons extrait de la littérature les informations pertinentes concernant les relations entre les protéines impliquées dans la transduction des signaux hormonaux. Le réseau a ensuite été modélisé en utilisant un formalisme logique et qualitatif pour pallier l'absence de données quantitatives. Tout d'abord, Les résultats ont permis de confirmer que l'auxine et les BRs agissent en synergie pour contrôler la croissance de la cellule, puis, d'expliquer des observations phénotypiques paradoxales et au final, de mettre à jour une interaction clef entre deux protéines dans la maintenance du méristème de la racine. Une étude ultérieure chez la plante modèle Brachypodium dystachion (Brachypo- dium) a révélé l'ajustement du réseau d'interaction croisée entre auxine et éthylène par rapport à Arabidopsis. Chez ce dernier, interférer avec la biosynthèse de l'auxine mène à la formation d'une racine courte. Néanmoins, nous avons isolé chez Brachypodium un mutant hypomorphique dans la biosynthèse de l'auxine qui affiche une racine plus longue. Nous avons alors conduit une analyse morphométrique qui a confirmé que des cellules plus anisotropique (plus fines et longues) sont à l'origine de ce phénotype racinaire. Des analyses plus approfondies ont démontré que la différence phénotypique entre Brachypodium et Arabidopsis s'explique par une inversion de la fonction régulatrice dans la relation entre le réseau de signalisation par l'éthylène et la biosynthèse de l'auxine. L'analyse morphométrique utilisée dans l'étude précédente exploite le pipeline de traitement d'image de notre méthode d'histologie quantitative. Pendant la croissance secondaire, la symétrie bilatérale de l'hypocotyle est remplacée par une symétrie radiale et une organisation concentrique des tissus constitutifs. Ces tissus sont initialement composés d'une douzaine de cellules mais peuvent aisément atteindre des dizaines de milliers dans les derniers stades du développement. Cette échelle dépasse largement le seuil d'investigation par les moyens dits 'traditionnels' comme l'imagerie directe de tissus en profondeur. L'étude de ce système pendant cette phase de développement ne peut se faire qu'en réalisant des coupes fines de l'organe, ce qui empêche une compréhension des phénomènes cellulaires dynamiques sous-jacents. Nous y avons remédié en proposant une stratégie originale nommée, histologie quantitative. De fait, nous avons extrait l'information contenue dans des images de très haute résolution de sections transverses d'hypocotyles en utilisant un pipeline d'analyse et de segmentation d'image à grande échelle. Nous l'avons ensuite combiné avec un algorithme de reconnaissance automatique des cellules. Cet outil nous a permis de réaliser une description quantitative de la progression de la croissance secondaire révélant des schémas développementales non-apparents avec une inspection visuelle classique. La formation de pôle de phloèmes en structure répétée et espacée entre eux d'une longueur constante illustre les bénéfices de notre approche. Par ailleurs, l'exploitation approfondie de ces résultats a montré un changement de croissance anisotropique des cellules du cambium et du phloème qui semble en phase avec l'expansion du xylème. Combinant des outils génétiques et de la modélisation biomécanique, nous avons démontré que seule la croissance plus rapide des tissus internes peut produire une réorientation de l'axe de croissance anisotropique des tissus périphériques. Cette prédiction a été confirmée par le calcul du ratio des taux de croissance du xylème et du phloème au cours de développement secondaire ; des ratios élevés sont effectivement observés et concomitant à l'établissement progressif et tangentiel du cambium. Ces résultats suggèrent un mécanisme d'auto-organisation établi par un gradient de division méristématique qui génèrent une distribution de contraintes mécaniques. Ceci réoriente la croissance anisotropique des tissus périphériques pour supporter la croissance secondaire. - Plants are essential for human society, because our daily food, construction materials and sustainable energy are derived from plant biomass. Yet, despite this importance, the multiple developmental aspects of plants are still poorly understood and represent a major challenge for science. With the emergence of high throughput devices for genome sequencing and high-resolution imaging, data has never been so easy to collect, generating huge amounts of information. Computational analysis is one way to integrate those data and to decrease the apparent complexity towards an appropriate scale of abstraction with the aim to eventually provide new answers and direct further research perspectives. This is the motivation behind this thesis work, i.e. the application of descriptive and predictive analytics combined with computational modeling to answer problems that revolve around morphogenesis at the subcellular and organ scale. One of the goals of this thesis is to elucidate how the auxin-brassinosteroid phytohormone interaction determines the cell growth in the root apical meristem of Arabidopsis thaliana (Arabidopsis), the plant model of reference for molecular studies. The pertinent information about signaling protein relationships was obtained through the literature to reconstruct the entire hormonal crosstalk. Due to a lack of quantitative information, we employed a qualitative modeling formalism. This work permitted to confirm the synergistic effect of the hormonal crosstalk on cell elongation, to explain some of our paradoxical mutant phenotypes and to predict a novel interaction between the BREVIS RADIX (BRX) protein and the transcription factor MONOPTEROS (MP),which turned out to be critical for the maintenance of the root meristem. On the same subcellular scale, another study in the monocot model Brachypodium dystachion (Brachypodium) revealed an alternative wiring of auxin-ethylene crosstalk as compared to Arabidopsis. In the latter, increasing interference with auxin biosynthesis results in progressively shorter roots. By contrast, a hypomorphic Brachypodium mutant isolated in this study in an enzyme of the auxin biosynthesis pathway displayed a dramatically longer seminal root. Our morphometric analysis confirmed that more anisotropic cells (thinner and longer) are principally responsible for the mutant root phenotype. Further characterization pointed towards an inverted regulatory logic in the relation between ethylene signaling and auxin biosynthesis in Brachypodium as compared to Arabidopsis, which explains the phenotypic discrepancy. Finally, the morphometric analysis of hypocotyl secondary growth that we applied in this study was performed with the image-processing pipeline of our quantitative histology method. During its secondary growth, the hypocotyl reorganizes its primary bilateral symmetry to a radial symmetry of highly specialized tissues comprising several thousand cells, starting with a few dozens. However, such a scale only permits observations in thin cross-sections, severely hampering a comprehensive analysis of the morphodynamics involved. Our quantitative histology strategy overcomes this limitation. We acquired hypocotyl cross-sections from tiled high-resolution images and extracted their information content using custom high-throughput image processing and segmentation. Coupled with an automated cell type recognition algorithm, it allows precise quantitative characterization of vascular development and reveals developmental patterns that were not evident from visual inspection, for example the steady interspace distance of the phloem poles. Further analyses indicated a change in growth anisotropy of cambial and phloem cells, which appeared in phase with the expansion of xylem. Combining genetic tools and computational modeling, we showed that the reorientation of growth anisotropy axis of peripheral tissue layers only occurs when the growth rate of central tissue is higher than the peripheral one. This was confirmed by the calculation of the ratio of the growth rate xylem to phloem throughout secondary growth. High ratios are indeed observed and concomitant with the homogenization of cambium anisotropy. These results suggest a self-organization mechanism, promoted by a gradient of division in the cambium that generates a pattern of mechanical constraints. This, in turn, reorients the growth anisotropy of peripheral tissues to sustain the secondary growth.

Impact du virus du Nil occidental sur les caractéristiques de la population de corneilles au Québec

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Non-linear boundary element formulation with tangent operator to analyse crack propagation in quasi-brittle materials

This work deals with analysis of cracked structures using BEM. Two formulations to analyse the crack growth process in quasi-brittle materials are discussed. They are based on the dual formulation of BEM where two different integral equations are employed along the opposite sides of the crack surface. The first presented formulation uses the concept of constant operator, in which the corrections of the nonlinear process are made only by applying appropriate tractions along the crack surfaces. The second presented BEM formulation to analyse crack growth problems is an implicit technique based on the use of a consistent tangent operator. This formulation is accurate, stable and always requires much less iterations to reach the equilibrium within a given load increment in comparison with the classical approach. Comparison examples of classical problem of crack growth are shown to illustrate the performance of the two formulations. (C) 2009 Elsevier Ltd. All rights reserved.

A method to analyse the alignment of core values in collaborative networked organisations

Since collaborative networked organisations are usually formed by independent and heterogeneous entities, it is natural that each member holds his own set of values, and that conflicts among partners might emerge because of some misalignment of values. In contrast, it is often stated in literature that the alignment between the value systems of members involved in collaborative processes is a prerequisite for successful co-working. As a result, the issue of core value alignment in collaborative networks started to attract attention. However, methods to analyse such alignment are lacking mainly because the concept of 'alignment' in this context is still ill defined and shows a multifaceted nature. As a contribution to the area, this article introduces an approach based on causal models and graph theory for the analysis of core value alignment in collaborative networks. The potential application of the approach is then discussed in the virtual organisations' breeding environment context.

Activités d’écriture approchée et entrée dans l’écrit des jeunes enfants: analyse comparative de démarches didactiques en première primaire en france

Nous présentons le suivi d’une cohorte d’élèves, de la grande section (troisième année de maternelle en France -5 ans) à la fin du CE1 (deuxième année de primaire –7/8 ans). La population est constituée d’un groupe contrôle et d’un groupe expérimental pratiquant des séances hebdomadaires d’écriture approchée, observées et filmées à différentes périodes de l’année (octobre, mars et juin). Dans notre contribution, nous analysons les séances filmées en fin de CP (première primaire), dans une perspective essentiellement comparatiste. L’objectif est de décrire la démarche didactique mise en œuvre par les enseignantes lors de séances d’enseignement de l’écriture. L'analyse des productions d'écrit et des verbalisations des élèves nous permet également d'évaluer ces démarches d’enseignement et de caractériser celle qui semble le plus propice au développement de compétences métalinguistiques des apprentis scripteurs

Analyse paléoécologique des formations récifales du golfe de Skoura (bordure méridionale du sillon Sud rifain; SE de Fés; Maroc). Implications paléogéographiques: communications Atlantique - Méditerranée au Miocène Terminal

The reef levels of the gulf of Skoura belong to the reef formation of the Upper Miocene of the South-Rifan straits. A detailed analysis of the vertical distribution of various forms of colonies has led to the establishment of precise coral morphologies zonation. This palaeoecological approach leads us to distinguish between two environments in the Skoura gulf, probably corresponding to two reef episodes. The palaeogeographical implications (relationships between the Atlantic ocean and the Mediterranean sea) will be pointed out.

Analyse paléoécologique des formations récifales du golfe de Skoura (bordure méridionale du sillon Sud rifain; SE de Fés; Maroc) implications paléogéographiques: communications Atlantique - Méditerranée au Miocène Terminal

The reef levels of the gulf of skoura belong to the reef formation of the Upper Miocene of the South-Rifan straits. A detailed analysis of the vertical distribution of various forms of colonies has led to the establishment of precise coral morphologies zonation. This palaeoecological approach leads us to distinguish between two environments in the Skoura gulf, probably corresponding to two reef episodes. The palaeogeographical implications (relationships between the Atlantic ocean and the Mediterranean sea) will be pointed out.

Data Extraction Tool to Analyse, Transform and Store Real Data from Electricity Markets

The study of electricity markets operation has been gaining an increasing importance in the last years, as result of the new challenges that the restructuring process produced. Currently, lots of information concerning electricity markets is available, as market operators provide, after a period of confidentiality, data regarding market proposals and transactions. These data can be used as source of knowledge to define realistic scenarios, which are essential for understanding and forecast electricity markets behavior. The development of tools able to extract, transform, store and dynamically update data, is of great importance to go a step further into the comprehension of electricity markets and of the behaviour of the involved entities. In this paper an adaptable tool capable of downloading, parsing and storing data from market operators’ websites is presented, assuring constant updating and reliability of the stored data.

La Réforme des soins en santé mentale en Belgique: analyse d'un modéle

RESUMO: O relatório anual de 2001 da Organização Mundial de Saúde (OMS), anunciou o interesse social dos problemas crescentes em matéria de saúde mental e relativo à necessidade urgente de uma extensão, como também, para uma melhor organização da oferta de tratamento. Sob proposta da Bélgica, esta observação foi traduzida em uma resolução « Mental health :responding to the call for action » (déclaração de intenção do 18 de maio de 2002). Nós notamos que certos países, como os Estados Unidos ou a Grã Bretanha transformam sistematicamente o tratamento residencial em um tratamento mais dirigido para a comunidade. Eles também se concentram na descoberta prematura dos problemas psiquiátricos. Este fenômeno de désinstitutionalisação obteve resultados concretos e traz um ganho certo, tanto para os atores do campo da saúde mental, como também para os candidatos a um tratamento. O tratamento das pessoas dentro do seu meio de vida é muito claramente reconhecido. As evoluções que marcaram os tratamentos em saúde mental na Bélgica durante estes utimos 40 anos mostram que vários paços importantes já foram feitos. A reforma tem como objetivo converter a oferta hospitalar e montar tratamentos dirigidos para e dentro da comunidade pela criação de equipas móveis que se inscrevem no dispositivo comunitário, historicamente muito activo bem que sub-financiado. A reorganização dos sistemas de tratamento está baseada na criação de redes, para construir um dispositivo flexível e contínuo que considera as necessidades dos pacientes. Esta reforma é, ao mesmo tempo, ambiciosa e complexa,. É uma visão nova, uma mudança de cultura, não só, para todos os atores da saúde mental, mas também para os pacientes e suas famílias. A reforma está baseada numa visão global e integrada que associa no mesmo movimento todas as autoridades competentes relativamente a saúde que elas sejam federais, regionais ou comunitárias.-----------ABSTRACT: The World Health Organization’s (WHO) annual report of 2001 identified a social interest for the increasing problems related to mental health and the urgent need of an extension and a better organization of mental health care. On a proposal of Belgium this statement was transformed into a resolution « Mental health: responding to the call for action» (Declaration of Intent, May 18th, 2002). Some countries such as the USA or the UK systematically dismantled in-patient residential care in favor of more community-based care and a focus on early detection of psychiatric problems. This de -institutionalization has clearly and concretely paid off and the value of bringing mental health care to claimants and treating them in their own residence was acknowledged. In Belgium, the evolutions which have shaped mental health care in the last forty years indicate that a number of important steps are already taken. The Reform aims to convert the supply of hospital care into community-based mental health care services through the creation of mobile teams which offer services in everyday life of the user. These teams take place in the community, historically highly active howbeit underfunded. The reorganization of health care system relies upon the creation of networks in order to build a flexible and continuous device which take into account user’s needs. This Reform can be seen as both ambitious and complex. It is a completely new vision, a major cultural shift for all mental health care stakeholders, but also for users and their relatives. The Reform is based on a global and integrated approach which links I, a same movement all relevant health authorities whether they be federal, regional or community. de-institutionalization – community mental health – recovery - users and families involvement - networking.

A systematic methodology to analyse the performance and design configurations of business interoperability in cooperative industrial networks

This thesis proposes a methodology for modelling business interoperability in a context of cooperative industrial networks. The purpose is to develop a methodology that enables the design of cooperative industrial network platforms that are able to deliver business interoperability and the analysis of its impact on the performance of these platforms. To achieve the proposed objective, two modelling tools have been employed: the Axiomatic Design Theory for the design of interoperable platforms; and Agent-Based Simulation for the analysis of the impact of business interoperability. The sequence of the application of the two modelling tools depends on the scenario under analysis, i.e. whether the cooperative industrial network platform exists or not. If the cooperative industrial network platform does not exist, the methodology suggests first the application of the Axiomatic Design Theory to design different configurations of interoperable cooperative industrial network platforms, and then the use of Agent-Based Simulation to analyse or predict the business interoperability and operational performance of the designed configurations. Otherwise, one should start by analysing the performance of the existing platform and based on the achieved results, decide whether it is necessary to redesign it or not. If the redesign is needed, simulation is once again used to predict the performance of the redesigned platform. To explain how those two modelling tools can be applied in practice, a theoretical modelling framework, a theoretical Axiomatic Design model and a theoretical Agent-Based Simulation model are proposed. To demonstrate the applicability of the proposed methodology and/or to validate the proposed theoretical models, a case study regarding a Portuguese Reverse Logistics cooperative network (Valorpneu network) and a case study regarding a Portuguese construction project (Dam Baixo Sabor network) are presented. The findings of the application of the proposed methodology to these two case studies suggest that indeed the Axiomatic Design Theory can effectively contribute in the design of interoperable cooperative industrial network platforms and that Agent-Based Simulation provides an effective set of tools for analysing the impact of business interoperability on the performance of those platforms. However, these conclusions cannot be generalised as only two case studies have been carried out. In terms of relevance to theory, this is the first time that the network effect is addressed in the analysis of the impact of business interoperability on the performance of networked companies and also the first time that a holistic approach is proposed to design interoperable cooperative industrial network platforms. Regarding the practical implications, the proposed methodology is intended to provide industrial managers a management tool that can guide them easily, and in practical and systematic way, in the design of configurations of interoperable cooperative industrial network platforms and/or in the analysis of the impact of business interoperability on the performance of their companies and the networks where their companies operate.