Ce travail de thèse cherche à mieux caractériser le comportement des matériaux hétérogènes sous cisaillement avec une approche multi-échelles (macro-méso-microscopique).Cela est rendu possible en développant un montage innovant qui couple un rhéomètre à un système d’imagerie de speckle résolue spatialement et temporellement (RheoSpeckle). Nous montrons la validation de notre expérience en l’appliquant sur deux matériaux parfaits : un solide et un liquide. Sur le solide, on mesure le champ de déplacement sur les images de speckle avec une résolution meilleure que 1 µm. Puis on prouve l’élasticité du matériau à l’échelle microscopique. Sur le liquide, la taille des nanoparticules est déterminée avec un excellent accord avec la spécification du fabriquant. Le champ de vitesse dans l’entrefer du Couette est calculé avec une bonne précision sur un temps inférieur à 1 s et avec une résolution spatiale de 100 µm sur 5mm. La dynamique microscopique d’une solution brownienne est étudiée et l’influence du cisaillement sur la décorrélation est déterminée. Nous montrons les capacités de notre expérience à étudier des matériaux hétérogènes en l’appliquant sur une solution concentrée de micelles géantes. La rhéologie linéaire est étudiée en rhéometrie classique mais aussi en utilisant l’imagerie du speckle. La rhéologie non linéaire de ce matériau est déterminé en rhéometrie (macro) mais aussi en calculant le champ de vitesse et l’intensité des images de speckle (méso) ou on caractérise les bandes de cisaillement qui se forment à partir d’un cisaillement critique. En fin la relaxation spatio-temporelle des bandes de cisaillement (micro) est caractérisée. On observe pour la première fois l’existence de deux temps de relaxation après l’arrêt du cisaillement et que la relaxation des bandes est relativement lente. / This work tries to better characterize the behavior of homogeneous and heterogeneous materials under shear with a multi-scale approach (macro-meso-micro-scopic). To do that, we have developed an innovative setup by coupling a rheometer to a speckle imaging geometry witch is spatially and temporally resolved (RheoSpeckle). We validate our experience using two perfect materials: a solid and a pure viscous fluid. On a solid sample, we calculate the displacement field on the speckle images with a resolution better than 1 µm. we demonstrate than, the microscopic elasticity of this material. On a pure viscous fluid, we measured the nanoparticle’s size with excellent accuracy. When a constant shear rate is applied, the velocity profile is measured with a time less than 1 s with a spatial resolution of 100 µm over 5 mm. The microscopic dynamic of a Brownian solution under shear is probed and the shear induced on the decorrelation of the intensity correlation function is studied. We show the capabilities of our experience using a concentrated solution of wormlike micelles. The linear rheology is studied using rheometric measurements and our speckle imaging system. Nonlinear rheology is studied using rheometric measurements (macro), but also by calculating the velocity filed and the intensity of speckle images (meso). With mesocopics measurements, the formation of shear banding is proved and characterized. Finally, the spatio-temporal relaxation (micro) of shear bands of this material is studied. We show for the first time the existence of two relaxations times after shear and that the relaxation of bands is relatively slow.

Neste trabalho estudamos, no contexto de campo médio, modelos microscópicos que possam descrever o comportamento termodinâmico das fases nemáticas em sistemas líquido-cristalinos. Considerando apenas interações atrativas, investigamos modelos de interações quadrupolares para objetos intrinsecamente biaxiais. Esses modelos apresentam mesofases nemáticas uniaxiais e biaxiais, pontos triplos e multicríticos (tricríticos, pontos de Landau, etc.). Ainda no contexto de forças atrativas, introduzimos um modelo de mistura binária de objetos intrinsecamente uniaxiais e objetos intrinsecamente biaxiais, numa formulação annealed. Essa mistura apresenta diagramas de fases bastante ricos, com topologias diversas, onde identificamos estruturas uniaxiais e biaxiais, fases reentrantes e uma grande variedade de pontos multicríticos (tricríticos, pontos críticos terminais, etc.). No caso de interações estéricas, estudamos uma teoria do funcional densidade para sistemas anisotrópicos densos, construída a partir de uma aproximação de van der Waals. Para esferoides prolatos, o modelo prevê um espaço de orientações com regiões não-acessíveis para as partículas. Além disso, o sistema apresenta uma região de coexistência entre as fases nemática e isotrópica. / We study, in a mean-field approximation, microscopic models which can lead to nematic liquid-crystalline phases. Considering attractive forces, we investigate models with quadrupolar interactions for intrinsically biaxial objects. These models present uniaxial and biaxial nematic mesophases, triple and multicritical points (tricritical point, Landau point, etc.). We also introduce a model for a binary mixture of intrinsically uniaxiail and biaxial objects, in an annealed treatment. The mixture exhibits phase diagrams with very rich topologies, where we find uniaxial and biaxial structures, reentrant phases and many different multicritical behaviors (tricritical point, critical endpoint, etc.). Moreover, assuming steric interactions, we investigate a density functional theory for hard anisotropic bodies at high densities, based on a van der Waals approximation. For hard spheroids, the model leads to an orientation space with forbidden regions for the particles. Also, the system phase separates in a nematic and an isotropic phases.

O objetivo dessa pesquisa foi determinar parâmetros qualitativos da madeira de Pinus caribaea var. bahamensis em 3 classes de diâmetro com uma classe comum, nos plantios 1969 e 1992, da Floresta Estadual de Manduri do Instituto Florestal - SP. Foram coletadas 3 árvores por classe e retiradas toras de 3 m. de altura. De cada tora foi retirada a prancha principal e desta retiradas amostras da região da base e do topo. Foram realizadas medições do lenho inicial e tardio de cada anel de crescimento para construção do gráfico de distribuição dos anéis de crescimento de cada árvore. Também foi realizada a amostragem paralela à medula, a amostragem acompanhando o anel de crescimento e na primeira tora a amostragem acompanhando o anel no topo da tora para a realização dos ensaios físicos e mecânicos. As curvas das isopropriedades puderam então ser determinadas. Nas árvores de mesma idade e diâmetro diferentes, as variações das dimensões das traqueídes foram observados nos 3º, 6º, 9º, 12º e 15º anel de crescimento e entre o lenho inicial e tardio. Entre as diferentes idades foi determinado se as variações no 16º(último anel de crescimento) das árvores jovens foram correspondentes ao 16º(anel de crescimento) nas árvores adultas. Também foi determinado se havia variações das dimensões das traqueídes nos últimos anéis de crescimento nas duas idades. Os resultados demonstraram: a)- as características anatômicas foram compatíveis para a espécie; b)- as dimensões das traqueídes variaram no sentido radial, entre idades diferentes e mesma classe e mostraram nas árvores jovens o menor valor de comprimento e espessura da parede e o maior valor de diâmetro tangencial e lume das traqueídes; o crescimento variou entre o 9º e 12º anel de crescimento,. c) a variação entre o lenho inicial e tardio nos 16º anéis de crescimento das árvores de menor idade comparada com os das árvores adultas, não apresentou um padrão definido; (d)- na comparação entre os últimos anéis de crescimento das árvores de idades diferentes o lenho inicial e tardio apresentou um padrão mais homogêneo. As curvas de isopropriedades mostraram o mesmo padrão de distribuição tanto das isopropriedades físicas como das mecânicas. Os tipos de amostras adotadas não apresentaram variações entre si. Os valores médios de cada isopropriedade no sentido axial mostraram os maiores valores de isodensidade aparente nas árvores adultas; para isoproporção de lenho inicial os maiores valores foram verificados nas árvores mais jovens e foram decrescentes no sentido radial; para isoproporção de lenho tardio e para isomódulo de elasticidade e ruptura, os maiores valores foram observados nas árvores adultas e foram crescentes da medula para a casca. Entre as idades estudadas verificam-se diferenças de distribuição das isopropriedades. O conhecimento da distribuição das curvas de isopropriedades possibilita um melhor aproveitamento de madeira. / The objective of this research has been to determine qualitative parameters of Pinus caribaea var. bahamensis wood in three diameter classes with a common base in 1969 and 1992 plantations from Floresta Estadual from the Manduri Instituto Florestal SP. three trees per class were collected and 3-m high logs were removed. From each log the main plank was removed and from this samples were taken from the base and top regions. Measurements of the early and late wood from each growth ring were made so that the distribution graph of the growth rings from each tree could be made. In order for the physical and mechanical tests to be made samplings were taken parallel to the pith, following the growth ring, and, in the first log, a sampling following the ring at the top of the log. The isoproperty curves could then be established. In the trees of same age and different diameters the variations in tracheid dimensions were examined at the 3rd, 6th, 9th, 12th, and 15th growth ring, and between early and late wood. Among different ages it was determined whether the variations at the 16th (last growth ring) of the young trees were equivalent to the 16th (growth ring) in adult trees. It was also determined whether there was any variation in tracheid dimensions in the last growth ring of the two ages. The results showed that: a) the anatomical characteristics were compatible for the species; b) the tracheid dimensions varied in the radial direction among different ages and same class, and showed in the young trees the lowest value for length and wall width, and the largest value for tangential diameter and tracheid lumen; the growth varied between the 9th and the 12th growth ring; c) the variation between early and late wood in the 16th growth rings of the youngest trees, as compared to adult trees did not show a definite pattern; d) in the comparison among the last growth ring of trees of different ages the early and late wood showed a nore homogeneous pattern. The isoproperty curves showed the same distribution pattern, both of the physical and mechanical isoproperties. The kinds of samples used did not show variations from each other. The average values for each isoproperty in the axial direction showed the greatest values of apparent isodensity in adult trees; concerning the isoproportion of early wood, the greatest values were found in the youngest trees and decreased in the radial direction; concerning the isoproportion of late wood, and elasticity and rupture isomodule the greatest values were found in adult trees and decreased from pith to bark. Among the ages studied differences in the distribution of isoproperties can be found. The knowledge of the distribution of the isoproperty curves permits an improved use of the wood.

Ce travail porte sur l'analyse d'images numériques biologiques. Il vise à définir et mettre en œuvre des processus de mesures automatiques de données biologiques à partir d'images numériques dans un cadre de traitement de masse, et aborde notamment : l'incidence des choix méthodologiques sur la stabilité des résultats, l'étude de la validation des mesures produites et les limites de la généricité des méthodes et modèles appliquées à la biologie végétale.La réflexion est menée dans le cadre de l'étude de certaines organisations cellulaires, et plus particulièrement de l'identification et l'analyse automatique de files cellulaires dans des mosaïques d'images microscopiques de bois. En effet, l'étude des tendances biologiques le long de ces structures est nécessaire pour comprendre la mise en place des différentes organisations et maturations de cellule. Elle ne peut être conduite qu'à partir d'une grande zone d'observation du plan ligneux. Pour cela,- nous avons mis en place un nouveau protocole de préparation (rondelles de bois poncées) et de numérisation des échantillons permettant d'acquérir entièrement la zone d'observation sans biais- nous avons développé une chaîne de traitement permettant l'extraction automatique des files cellulaires dans des mosaïques images numériques.- nous avons proposé des indices de fiabilité pour chaque mesure effectuée afin de mieux cibler les études statistiques à venir.Les méthodes développées dans la thèse permettent l'acquisition et le traitement rapide d'un volume important de données. Ces données devraient servir de base à de nombreuses investigations : des analyses architecturales des arbres avec le suivi de file cellulaire et/ou la détection de perturbations biologiques, des analyses de variabilité intra et inter arbres permettant de mieux comprendre la croissance endogène des arbres. / This study focuses on biological numeric picture processes. It aims to define and implement new automated measurements at large scale analysis. Moreover, this thesis addresses: The incidence of the proposed methodology on the results reliability measurements accuracy definition and analysis proposed approaches reproducibility limits when applied to plant biology.This work is part of cells organization study, and aims to automatically identify and analyze the cell lines in microscopic mosaic wood slice pictures. Indeed, the study of biological tendencies among the cells lines is necessary to understand the cell migration and organization. Such a study can only be realized from a huge zone of observation of wood plane. To this end, this work proposes:- a new protocol of preparation (slices of sanded wood) and of digitizing of samples, in order to acquire the entire zone of observation without bias,- a novel processing chain that permit the automated cell lines extraction in numeric mosaic pictures,- reliability indexes for each measurement for further efficient statistical analysis.The methods developed during this thesis enable to acquire and treat rapidly an important volume of information. Those data define the basis of numerous investigations, such as tree architectural analysis cell lines following and/or detection of biological perturbations. And it finally helps the analysis of the variability intra- or inter- trees, in order to better understand the tree endogenous growth.

<p>In a prospective randomised double-blind study eighty patients with MRI verified lumbar disc herniation and corresponding clinical findings underwent microscopic disc removal. The patients were peroperatively given systemic and local corticosteroids or placebo, and followed for 2 years. The hospital stay and time to return to full-time work was significantly shorter in the treatment group. Pain measured as worst pain during the last week was also lower in the corticosteroid group. The results indicate that peroperative treatment with corticosteroids reduces pain and improves the functional outcome in patients operated for lumbar disc herniations.</p><p>To evaluate whether thermal quantitative sensory testing (QST) is applicable in the study of sensory dysfunction in lumbar disc herniations 66 patients with disc herniations underwent thermal QST. We found that thermal QST reflects sensory dysfunction in patients with lumbar disc herniations. However, thermal QST seems to have a poor predictive value for identifying the anatomic location of a herniated lumbar disc.</p><p>Quantitative sensory testing (QST) was used to detect damage to the myelinated A-delta fibres (cold sense) and the unmyelinated C-fibres (warmth sense). Corticosteroids combined with surgery in lumbar disc surgery improved the normalisation for the warmth disturbance compared to the control group. </p><p>A prospective analysis was performed on the predictive value of preoperatively determined lumbar lordosis and flexion for pain and disability in patients treated by microscopic lumbar disc surgery. Preoperative hyperlordosis correlated to more pain postoperatively (p=0.004). In patients with hypoflexion there was an association between hyperlordosis and moderate or severe pain postoperatively (p<0.001). The same outcomes were found for DRI. The stiff and straight back indicates a good outcome of lumbar disc surgery concerning pain and disability. </p>

In a prospective randomised double-blind study eighty patients with MRI verified lumbar disc herniation and corresponding clinical findings underwent microscopic disc removal. The patients were peroperatively given systemic and local corticosteroids or placebo, and followed for 2 years. The hospital stay and time to return to full-time work was significantly shorter in the treatment group. Pain measured as worst pain during the last week was also lower in the corticosteroid group. The results indicate that peroperative treatment with corticosteroids reduces pain and improves the functional outcome in patients operated for lumbar disc herniations. To evaluate whether thermal quantitative sensory testing (QST) is applicable in the study of sensory dysfunction in lumbar disc herniations 66 patients with disc herniations underwent thermal QST. We found that thermal QST reflects sensory dysfunction in patients with lumbar disc herniations. However, thermal QST seems to have a poor predictive value for identifying the anatomic location of a herniated lumbar disc. Quantitative sensory testing (QST) was used to detect damage to the myelinated A-delta fibres (cold sense) and the unmyelinated C-fibres (warmth sense). Corticosteroids combined with surgery in lumbar disc surgery improved the normalisation for the warmth disturbance compared to the control group. A prospective analysis was performed on the predictive value of preoperatively determined lumbar lordosis and flexion for pain and disability in patients treated by microscopic lumbar disc surgery. Preoperative hyperlordosis correlated to more pain postoperatively (p=0.004). In patients with hypoflexion there was an association between hyperlordosis and moderate or severe pain postoperatively (p&lt;0.001). The same outcomes were found for DRI. The stiff and straight back indicates a good outcome of lumbar disc surgery concerning pain and disability.

The utility of dental calculus as a proxy for diet and mouth use is explored for the Middle Holocene Cis-Baikal region of Central Siberia based on two methods: a macroscopic analysis of severity and a microscopic analysis of particles within deposits. The study area was inhabited by two culturally and biologically distinct cultures, the Early Neolithic (EN) Kitoi culture (8,000 to 7,000/6,800 cal B.P.) and the Late Neolithic-Early Bronze Age (LN-EBA) Isakovo-Serovo-Glaskovo (ISG) cultural complex (6,000/5,800 to 4,000 cal B.P.), separated by a period of cultural transition marked by a cessation in formal cemetery use. Data were collected from four cemetery sites, two dating to the EN and two dating to the LN-EBA. Nonparametric testing of calculus severity revealed that, for adult males and juveniles, lakeshore populations displayed greater affinity to each other than to their contemporaneous cultural counterpart populations living along riverine systems in the Angara River Valley. Trends within the EN cemetery Shamanka II contrasted to the other cemetery populations, with noticeably larger deposits in anterior quadrants and significant sexual distinctions. The proportion of protein to carbohydrates consumed is known to influence calculus formation, but both cultural groups lived on a diet based predominately on meat sources so dietary ratios alone do not adequately explain the differences distinguished. A complex multifactorial model involving microregional differences in resources/environment, foraging patterns, individual variation, and dental wear patterns provides at least a partial explanation for the results observed. A wide range of particles were recovered during the microscopic analysis of calculus, albeit in low concentrations. The low starch grain counts were consistent with a diet based predominately on meats but still provide some of the first direct evidence for plant consumption in the Cis-Baikal, including possible plant processing by cooking or grinding based on damage evident on the grains. Other particles recovered may provide evidence of mouth use activities or palaeoenvironmental influences. Together, the two components of this analysis offer strong evidence that dental calculus is a useful tool for reconstructing hunter-gatherer lifeways but also highlight the limitations of conducting this type of research on previously excavated and potentially contaminated material.

Ο ρόλος των Ευφυών Συστημάτων Μεταφορών είναι η βελτίωση της οδικής ασφάλειας, μέσω της έγκαιρης ανίχνευσης συμβάντων και της αποτελεσματικής διαχείρισης της κυκλοφορίας. Στο πλαίσιο αυτό, η έρευνα αυτή εστιάζει στην ανάλυση της σχέσης μεταξύ ενός καθημερινού σοβαρού φαινομένου της κυκλοφορίας, όπως το κυκλοφοριακό πλήγμα (shockwave) και τα οχήματα που κινούνται σε σχηματισμό cluster, μέσω του κυκλοφοριακού πλήγματος. Για να σχηματιστεί ένα cluster απαιτείται δύο ή περισσότερα οχήματα να περιλαμβάνονται στην ακολουθία οχημάτων είτε λόγω της εγγύτητάς τους είτε λόγω της σχετικής τους απόστασής από άλλα οχήματα. Ξεκινώντας με βίντεο κυκλοφοριακής στον αυτοκινητόδρομο I-94, Minnesota, USA, οι τροχιές των οχημάτων εξήχθησαν. Τα αποτελέσματα χρησιμοποιήθηκαν στη συνέχεια προκειμένου να καθοριστούν μεταβλητές όπως χρονοαπόσταση, ταχύτητα, επιτάχυνση για τρεις ομάδες οχημάτων, το Cluster, η ομάδα Πριν το Cluster και η ομάδα Μετά το Cluster. Η σχέση μεταξύ αυτών των ομάδων μελετήθηκε και αποτυπώθηκε σε γραμμικές συναρτήσεις με πολλαπλές ανεξάρτητες μεταβλητές. / The role of Intellignet Transportation Systems is to enhance traffic safety, through timely detection of incidents and effective traffic management. In this framework, this research focuses into analyzing the relationship between a daily severe traffic phenomenon such as shockwave and vehicles which move in cluster formation through the shockwave. For a cluster to be formed it is required for two or more vehicles to be included either because of their closeness or because of their relative distance from other vehicles on the link. Starting with video recordings of traffic flow on I-94, Minnesota, USA, vehicles trajectories were extracted. The results were then used in order to define variables such as vehicles space and time headway, velocity, acceleration for three groups of vehicles; the Cluster, the Before Cluster group and the After Cluster group. The relationship between these groups was studied and was modeled in linear functions with multiple variables.

The western embayment of Lake Ontario, Hamilton Harbour, is one of the most polluted sites in the Laurentian Great Lakes and in recent years has seen a reoccurrence of cyanobacterial blooms. This study uses a multidisciplinary approach to examine the presences of toxic Cyanobacteria in the harbour in order to gain insight into these recurrent blooms. Microscopic analyses of phytoplankton samples collected during the 2009 summer-fall sampling season from two locations within the harbour showed the spatial and seasonal diversity of the contemporary cyanobacterial community. Microcystis colonies relative abundances in relation to total algal numbers were estimated. The lowest and highest relative abundances of Microcystis in the phytoplankton population were 0.6% and 9.7%, respectively, and showed seasonal variability between stations. Fourteen cyanobacterial genera comprising six families and three orders were identified and for which the most abundant filamentous genera during the summer-fall sampling season were Planktothrix, Aphanizomenon and Limnothrix. Potential microcystin producers Microcystis, Planktothrix, Aphanizomenon and Dolichospermum were also present and during the sampling period Microcystis was recorded at both stations on all dates, however, its relative abundance was below 10 % throughout the study period. The composition and abundance of filamentous cyanobacteria were observed to be positively statistically correlated to water quality environmental parameters dissolved nitrates (NO3/NO2), dissolved inorganic carbon (DIC), and conductivity. Redundancy analysis (RDA) found that 53.35% total variance of Aphanizomenon was correlated to low water column NO3/NO2 and conductivity, and higher water column DIC. 58.13% of the relative abundance of Planktothrix was correlated to high concentrations of dissolved nitrates, while 51.69% of total variance of Limnothrix was correlated to higher DIC and lower water column dissolved nitrate concentrations. Information about past cyanobacterial communities was obtained from the sediment core analysis, using paleolimnological and modern molecular methods. The age of the 100.5 cm long sediment core retrieved from the deepest part of Hamilton Harbour was established to be 140 years (1869-2009), using the Constant Rate of Supply (CRS) 210Pb age model. This age was not sufficient to provide information of harbour’s environmental conditions, presence of the blooms, and triggers for their occurrence before European settlement in the area. Results of the HPLC analysis of fossil pigments indicated that the dominant members of the algal community have not changed over the 140 years and that cyanobacteria were regular members of the phytoplankton community. The composition of the major chlorophyll pigments indicated high presence of Chlorophyta and Bacillariophyta in the harbour at all times. The main algal groups identified on the basis of marker pigments presence, besides the Chlorophyta and Bacillariophyta, were the Dinophyta and the Cryptophyta. The presence of a scytonemin derivative, compound B, indicated that cyanobacterial blooms were occurring in past, before the first officially recorded blooms in the 1960s. Cyanobacterial pigments presence indicated that Cyanobacteria have been a regular but not dominant feature of Hamilton Harbour phytoplankton in the past. To our knowledge, this study is the first one examining fossil pigments from Hamilton Harbour. Results of the PCR-DGGE molecular analysis of 16S rRNA-V3 gene fragments from sedimentary DNA revealed the presence of thirteen cyanobacterial genotypes. The temporal change in the cyanobacterial community composition was indicated by the increasing number of species over time, from the oldest to the most recent sediment layers. The deepest sediment strata showed the lowest number (two bands) and intensity of bands. The most recent sediment layer had the greatest numbers (11) and intensity of bands. This increased diversity indicated changing environmental conditions in the harbour, primarily nutrient pollution and worsening water quality. Results of the PCR-DGGE molecular analysis of mcyE-AMT gene fragments showed that Microcystis aeruginosa and Planktothrix rubescens were two microcystin producers present in Hamilton Harbour over the last 80 years. The persistent presence and resilience of these two genera indicated a more serious and longer-term issue of toxic blooms than previously recognized. Historical records show that noticeable anthropogenic impact on Lake Ontario environment has been measurable since the 1780s, the first dramatic impact on the Lake Ontario watershed was evident from the mid1880s, the earliest evidence of eutrophication in the lake occurred between 1820 and 1850, while human induced environmental changes in Hamilton Harbour date back ca. 350 years. In the 1960s, cyanobacterial blooms were first officially recognized in the harbour and the lower Great Lakes. The present research is the first report of the mcyE module and AMT domain of microcystin genes being amplified from sediment of North American lakes, and showed that toxic Cyanobacterial have been regular members of Hamilton Harbour phytoplankton community for almost a century. This research considerably deepened the knowledge of the past toxic cyanobacterial blooms in Hamilton Harbour and their possible causes. It also showed that in the absence of historical records, both the PCR-DGGE method and the mcyE-AMT gene may be used for reconstruction of the past toxic blooms not only in the Laurentian Great Lakes, but also in other aquatic regions of the world impacted by toxic cyanobacterial blooms. Also, it demonstrated the utility of the combined molecular and paleolimnological analyses, which might become a useful tool in the determination of the bloom causes factors and in the mitigation of the future production of toxic blooms.

No description available.