Les modèles cinématiques de plissement permettent de prévoir l'architecture des anticlinaux en profondeur à partir de leurs géométries de surface. Bien que les modèles classiques de type « kink-band » soient faciles à utiliser, ils ne peuvent expliquer que des géométries de plis limitées. Le modèle trishear surmonte cet inconvénient, mais son application reste difficile à mettre en oeuvre notamment en raison de nombreux paramètres mal contraints tels que le rapport P/S et l'angle de trishear. Dans cette thèse, nous avons développé un modèle cinématique de plissement à angle d'inter-flancs variable qui permet de rendre compte de toutes les variétés géométriques de plis sur propagation de faille. Ce modèle est basé sur la géométrie « kink-band » et son application nécessite de connaître uniquement les paramètres de surface du pli (plongements des flancs, amplitude et longueur d'onde du pli). Le modèle permet de quantifier le rapport P/S du pli durant sa croissance, ainsi que son évolution tardive en pli de rupture. Le modèle a été appliqué à la chaîne plissée et faillée de l'Atlas tunisien pour estimer la profondeur du niveau de décollement des plis sur propagation de faille. Les résultats se corrèlent bien avec les données de subsurface, au contraire des autres modèles classiques et du modèle de trishear où il est difficile d’établir une relation entre la géométrie de surface des anticlinaux et leur architecture profonde. / Kinematic models of folding allow deducing the deep architecture of folds from their surface geometries. Classical models are easy to use because of their kink-band geometry but they are only able to explain some particular fold shapes. The trishear model overcomes this drawback, but its application remains limited because it necessitates the knowledge of several unconstrained parameters such as the P/S ratio and the trishear angle. In this work, we developed a kinematic model based on the variation of the inter-limb angle during the folding. The model allows accounting for all surface geometries of fault-propagation folds. Since this model is based on the kink-band geometry, its application only requires the knowledge of the fold surface parameters, i.e. the dip of both limbs and the fold amplitude and wavelength. The model is also able to quantify the P/S ratio during the fold growth, together with its latest evolutional stage as a breakthrough fold. We applied the model in the Tunisian Atlas fold-and-thrust belt to estimate the depth of the decollement level associated to fault-propagation anticlines. Results are in good agreement with subsurface data. In contrast, both the other classical and trishear models are unable to explain the relationship between the surface geometry of anticlines and their deep architecture.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A partir de 2011, ocorreram e ainda ocorrerão eventos de grande repercussão para a cidade do Rio de Janeiro, como a conferência Rio+20 das Nações Unidas e eventos esportivos de grande importância mundial (Copa do Mundo de Futebol, Olimpíadas e Paraolimpíadas). Estes acontecimentos possibilitam a atração de recursos financeiros para a cidade, assim como a geração de empregos, melhorias de infraestrutura e valorização imobiliária, tanto territorial quanto predial. Ao optar por um imóvel residencial em determinado bairro, não se avalia apenas o imóvel, mas também as facilidades urbanas disponíveis na localidade. Neste contexto, foi possível definir uma interpretação qualitativa linguística inerente aos bairros da cidade do Rio de Janeiro, integrando-se três técnicas de Inteligência Computacional para a avaliação de benefícios: Lógica Fuzzy, Máquina de Vetores Suporte e Algoritmos Genéticos. A base de dados foi construída com informações da web e institutos governamentais, evidenciando o custo de imóveis residenciais, benefícios e fragilidades dos bairros da cidade. Implementou-se inicialmente a Lógica Fuzzy como um modelo não supervisionado de agrupamento através das Regras Elipsoidais pelo Princípio de Extensão com o uso da Distância de Mahalanobis, configurando-se de forma inferencial os grupos de designação linguística (Bom, Regular e Ruim) de acordo com doze características urbanas. A partir desta discriminação, foi tangível o uso da Máquina de Vetores Suporte integrado aos Algoritmos Genéticos como um método supervisionado, com o fim de buscar/selecionar o menor subconjunto das variáveis presentes no agrupamento que melhor classifique os bairros (Princípio da Parcimônia). A análise das taxas de erro possibilitou a escolha do melhor modelo de classificação com redução do espaço de variáveis, resultando em um subconjunto que contém informações sobre: IDH, quantidade de linhas de ônibus, instituições de ensino, valor m médio, espaços ao ar livre, locais de entretenimento e crimes. A modelagem que combinou as três técnicas de Inteligência Computacional hierarquizou os bairros do Rio de Janeiro com taxas de erros aceitáveis, colaborando na tomada de decisão para a compra e venda de imóveis residenciais. Quando se trata de transporte público na cidade em questão, foi possível perceber que a malha rodoviária ainda é a prioritária

The emergence of drug resistant strains of Plasmodium has given a new face to the old disease, malaria. One of the approaches is to block metabolic pathways of the pathogen. The current thesis describes the X-ray crystallographic analysis of two enzymes of the fatty acid biosynthesis pathway of the malaria parasite Plasmodium falciparum. In order to understand the functional mechanism and mode of inhibitor binding, enzyme-inhibitor complexes were characterized, which could help in further improvement of the efficacy of the inhibitors and hence to fight against the disease. The introductory chapter of the thesis presents a discussion on malaria and different metabolic pathways of the pathogen which could be suitable targets for novel antimalarials. In continuation to that, the pathway of our choice the fatty acid biosynthesis and an overview of the structural features of the enzymes involved in the pathway that have been characterized from different organisms are also described. The second chapter includes the tools of X-ray crystallography that were used for structural studies of the present work. It also discusses the biochemical, biophysical and other computational methods used to further characterize the enzymes under study. Triclosan, a well known inhibitor of Enoyl Acyl Carrier Protein Reductase (FabI) from several pathogenic organisms, is a promising lead compound to design effective drugs. The X-ray crystal structures of Plasmodium falciparum FabI (PfFabI), in complex with triclosan variants having different substituted and unsubstituted groups at different key functional locations, were determined and compared with triclosan binding which form the basis of chapter 3. The structures revealed that 4 and 2’ substituted compounds have more interactions with the protein, cofactor and solvent molecules as compared to triclosan. New water molecules were found to interact with some of these inhibitors. Substitution at the 2’ position of triclosan caused the relocation of a conserved water molecule, leading to an additional hydrogen bond with the inhibitor. This observation can help in conserved water based inhibitor design. 2’ and 4’ unsubstituted compounds showed a movement away from the hydrophobic pocket to compensate for the interactions made by the halogen groups of triclosan. This compound also makes additional interactions with the protein and cofactor which compensates for the lost interactions due to the unsubstitution at 2’ and 4’. In cell culture, this inhibitor shows less potency, which indicates that the chlorines at 2’ and 4’ positions increase the ability of the inhibitor to cross multilayered membranes. This knowledge helps us to modify the different functional groups of triclosan to get more potent inhibitors. Certain residues in the substrate binding tunnel of PfFabI were mutated to identify the role of these residues in substrate binding and protein stability, which forms the 4th chapter of the thesis. The substrate binding site residue Ala372 of PfFabI has been mutated to Methionine and Valine which increased the affinity of the enzyme towards triclosan to almost double, close to that of Escherichia coli FabI (EcFabI) which has a Methionine at the structurally similar position of Ala372 of PfFabI. Kinetic studies of the mutants of PfFabI and the crystal structure analysis of the A372M mutant revealed that a more hydrophobic environment enhances the affinity of the enzyme for the inhibitor. A triclosan derivative showed a 3-fold increase in the affinity towards the mutants compared to the wild type, due to additional interactions with the A372M mutant as revealed by the crystal structure. The enzyme has a conserved salt bridge which stabilizes the substrate binding loop and appears to be important for the active conformation of the enzyme. A second set of mutants generated to check this hypothesis exhibited loss of function, except in one case where, the crystal structure showed that the substrate binding loop is stabilized by a water bridge network. The main focus of chapter 5 is β-Hydroxyacyl-acyl carrier protein dehydratase of Plasmoduim falciparum (PfFabZ) which catalyzes the third and important reaction of the fatty acid elongation cycle. The crystal structure of PfFabZ was available in its hexameric (active) and dimeric (inactive) forms. However, until now PfFabZ has not been crystallized with any bound inhibitors. We have designed a new condition to crystallize PfFabZ with its inhibitors bound in the active site, and determined the crystal structures of three of these complexes. This is the first report of the crystal structures of PfFabZ with competitive inhibitor complexes and the first such study on any FabZ enzyme with active site inhibitors. These inhibitors in the active site stabilize the substrate binding loop, revealing the substrate binding tunnel with an overall shape of “U”. In the crystal structure, the residue Phe169 located in the middle of the tunnel was found to be in two different conformations, open and closed, implying that it controls the length of the tunnel and makes it suitable for accommodating longer substrates merely by changing its side chain conformation. The hydrophobic nature of the substrate binding channel signifies the specificity for the hydrophobic tail of fatty acid substrates. The volume of the active site tunnel is determined by the sequence as well as by the conformation of the substrate binding site loop region and varies between organisms for accommodating fatty acids of different chain lengths. All PfFabZ inhibitors reported here bind to the active site through specific contacts like hydrogen bonds with catalytic residues and hydrophobic interactions. This report on the crystal structures of the complexes of PfFabZ provides the structural basis of the inhibitory mechanism of the enzyme, that could be used to improve the potency of inhibitors against an important component of fatty acid synthesis common to many infectious organisms. The hot dog fold has been found in more than sixty proteins since the first report of its existence about a decade ago. The fold appears to have a strong association with fatty acid biosynthesis, its regulation and metabolism, as the proteins with this fold are predominantly coenzyme A-binding enzymes with a variety of substrates located at their active sites. We have analyzed the structural features and sequences of proteins having the hot dog fold. This study reveals that though the basic architecture of the fold is well conserved in these proteins, significant differences exist in their sequence, nature of substrate and oligomerization. Segments with certain conserved sequence motifs seem to play crucial structural and functional roles in various classes of these proteins. The analysis discussed in chapter 6, led to predictions regarding the functional classification and identification of possible catalytic residues of a number of hot dog fold-containing hypothetical proteins whose structures were determined in high throughput structural genomics projects. Rv0098, predicted to be the FabZ of Mycobacterium tuberculosis, was cloned, expressed, purified, crystallized, and X-ray diffraction data were collected. Molecular replacement trials with all “hot dog” fold proteins failed to yield any significant solution due to the low sequence similarity (<20%) of Rv0098 compared to other FabZs. During the trials of structure solution by multiple isomorphous replacement method, structure of Rv0098 was published and it was shown to be a long-chain fatty acyl-CoA thioesterase (FcoT). The crystal structure of Rv0098 did not explain the molecular basis of substrate specificity of varying chain lengths. Molecular dynamics studies were carried out, which revealed that certain residues of the substrate binding tunnel are flexible and thus modulates the length of the tunnel. Flexibility of the loop at the base of the tunnel was also found to be important for determining the length of the tunnel for accommodating appropriate substrates. The structural basis of accommodating long chain substrates by Rv0098 is discussed in chapter 7, by combining the crystallographic and molecular dynamics studies. Part of the work presented in the thesis has been reported in the following publications. Karmodiya, K., Sajad, S., Sinha, S., Maity, K., Suguna, K. and Surolia, N. (2007) Conformational stability and thermodynamic characterization of homotetrameric Plasmodium falciparum beta-ketoacyl-ACP reductase. IUBMB Life 59, 441-9. Pidugu, L. S., Maity, K., Ramaswamy, K., Surolia, N. and Suguna, K. (2009) Analysis of proteins with the 'hot dog' fold: prediction of function and identification of catalytic residues of hypothetical proteins. BMC Struct Biol 9, 37. Kapoor, N., Banerjee, T., Babu, P., Maity, K., Surolia, N. and Surolia, A. (2009) Design, development, synthesis, and docking analysis of 2'-substituted triclosan analogs as inhibitors for Plasmodium falciparum enoyl-ACP reductase. IUBMB Life 61, 1083-91. Maity, K., Bhargav, S. P., Sankaran, B., Surolia, N., Surolia, A. and Suguna, K. (2010) X-ray crystallographic analysis of the complexes of enoyl acyl carrier protein reductase of Plasmodium falciparum with triclosan variants to elucidate the importance of different functional groups in enzyme inhibition. IUBMB Life 62, 467-76. Maity, K., Banerjee, T., Narayanappa, P., Surolia, N., Surolia, A. and Suguna, K. (2010) Effect of substrate binding loop mutations on the structure, kinetics and inhibition of Enoyl Acyl Carrier Protein Reductase from Plasmodium falciparum. (Communicated) Maity, K., Bharat, S. V., Kapoor, N., Surolia, N., Surolia, A. and Suguna, K. (2010) Insights into the functional and inhibitory mechanism of the β-Hydroxyacyl-Acyl Carrier Protein Dehydratase of Plasmodium falciparum from the crystal structures of its complexes with active site inhibitors. (Communicated)

No description available.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A partir de 2011, ocorreram e ainda ocorrerão eventos de grande repercussão para a cidade do Rio de Janeiro, como a conferência Rio+20 das Nações Unidas e eventos esportivos de grande importância mundial (Copa do Mundo de Futebol, Olimpíadas e Paraolimpíadas). Estes acontecimentos possibilitam a atração de recursos financeiros para a cidade, assim como a geração de empregos, melhorias de infraestrutura e valorização imobiliária, tanto territorial quanto predial. Ao optar por um imóvel residencial em determinado bairro, não se avalia apenas o imóvel, mas também as facilidades urbanas disponíveis na localidade. Neste contexto, foi possível definir uma interpretação qualitativa linguística inerente aos bairros da cidade do Rio de Janeiro, integrando-se três técnicas de Inteligência Computacional para a avaliação de benefícios: Lógica Fuzzy, Máquina de Vetores Suporte e Algoritmos Genéticos. A base de dados foi construída com informações da web e institutos governamentais, evidenciando o custo de imóveis residenciais, benefícios e fragilidades dos bairros da cidade. Implementou-se inicialmente a Lógica Fuzzy como um modelo não supervisionado de agrupamento através das Regras Elipsoidais pelo Princípio de Extensão com o uso da Distância de Mahalanobis, configurando-se de forma inferencial os grupos de designação linguística (Bom, Regular e Ruim) de acordo com doze características urbanas. A partir desta discriminação, foi tangível o uso da Máquina de Vetores Suporte integrado aos Algoritmos Genéticos como um método supervisionado, com o fim de buscar/selecionar o menor subconjunto das variáveis presentes no agrupamento que melhor classifique os bairros (Princípio da Parcimônia). A análise das taxas de erro possibilitou a escolha do melhor modelo de classificação com redução do espaço de variáveis, resultando em um subconjunto que contém informações sobre: IDH, quantidade de linhas de ônibus, instituições de ensino, valor m médio, espaços ao ar livre, locais de entretenimento e crimes. A modelagem que combinou as três técnicas de Inteligência Computacional hierarquizou os bairros do Rio de Janeiro com taxas de erros aceitáveis, colaborando na tomada de decisão para a compra e venda de imóveis residenciais. Quando se trata de transporte público na cidade em questão, foi possível perceber que a malha rodoviária ainda é a prioritária

Made available in DSpace on 2016-12-23T14:33:42Z (GMT). No. of bitstreams: 1 Dissertacao de Daniel Regis Sarmento Caon.pdf: 1566094 bytes, checksum: 67b557539f4bc5b354bc90066e805215 (MD5) Previous issue date: 2010-08-27 / This work aims to provide automatic cognitive assistance via speech interface, to the elderly who live alone, at risk situation. Distress expressions and voice commands are part of the target vocabulary for speech recognition. Throughout the work, the large vocabulary continuous speech recognition system Julius is used in conjunction with the Hidden Markov Model Toolkit(HTK). The system Julius has its main features described, including its modification. This modification is part of the contribution which is in this work, including the detection of distress expressions ( situations of speech which suggest emergency). Four different languages were provided as target for recognition: French, Dutch, Spanish and English. In this same sequence of languages (determined by data availability and the local of scenarios for the integration of systems) theoretical studies and experiments were conducted to solve the need of working with each new configuration. This work includes studies of the French and Dutch languages. Initial experiments (in French) were made with adaptation of hidden Markov models and were analyzed by cross validation. In order to perform a new demonstration in Dutch, acoustic and language models were built and the system was integrated with other auxiliary modules (such as voice activity detector and the dialogue system). Results of speech recognition after acoustic adaptation to a specific speaker (and the creation of language models for a specific scenario to demonstrate the system) showed 86.39 % accuracy rate of sentence for the Dutch acoustic models. The same data shows 94.44 % semantical accuracy rate of sentence / Este trabalho visa prover assistência cognitiva automática via interface de fala, à idosos que moram sozinhos, em situação de risco. Expressões de angústia e comandos vocais fazem parte do vocabulário alvo de reconhecimento de fala. Durante todo o trabalho, o sistema de reconhecimento de fala contínua de grande vocabulário Julius é utilizado em conjunto com o Hidden Markov Model Toolkit(HTK). O sistema Julius tem suas principais características descritas, tendo inclusive sido modificado. Tal modificação é parte da contribuição desse estudo, assim como a detecção de expressões de angústia (situações de fala que caracterizam emergência). Quatro diferentes linguas foram previstas como alvo de reconhecimento: Francês, Holandês, Espanhol e Inglês. Nessa mesma ordem de linguas (determinadas pela disponibilidade de dados e local de cenários de integração de sistemas) os estudos teóricos e experimentos foram conduzidos para suprir a necessidade de trabalhar com cada nova configuração. Este trabalho inclui estudos feitos com as linguas Francês e Holandês. Experimentos iniciais (em Francês) foram feitos com adaptação de modelos ocultos de Markov e analisados por validação cruzada. Para realizar uma nova demonstração em Holandês, modelos acústicos e de linguagem foram construídos e o sistema foi integrado a outros módulos auxiliares (como o detector de atividades vocais e sistema de diálogo). Resultados de reconhecimento de fala após adaptação dos modelos acústicos à um locutor específico (e da criação de modelos de linguagem específicos para um cenário de demonstração do sistema) demonstraram 86,39% de taxa de acerto de sentença para os modelos acústicos holandeses. Os mesmos dados demonstram 94,44% de taxa de acerto semântico de sentença

Dans la thèse nous nous occupons de l'estimation de la moyenne d'un petit domaine sous un modèle one-fold et utilisant MINQUE pour estimer les composantes de la variance, sous un modèle two-fold avec variances aléatoires, sous des plans noninformatifs et informatifs. / Doctorat en sciences, Orientation statistique / info:eu-repo/semantics/nonPublished

Microscopic video images of microcirculation have been used in clinical diagnosis for years, and theparameters obtained from images reveal most physiological activities and body organizations.Particularly, the blood flow speed is one of important indexes, which reflects the state ofmicrocirculation and make significant marks in diagnosis.In order to measure capillary blood velocity, a quantity of methods and instruments have beenstudied and developed. Based on the format of measurement, microscopy approaches used widely,can be grouped into two categories. One direct way applies microscopic-imaging technology forvisualization. The other way uses assistant methods such as laser-illumination [1] or labeling RBCswith fluorescein isothiocyanate [2]. In previous study, four methods (Direct Observation Method,Dual-windows Method, Single-window Method, Optical Flow Method) have been studied andanalysed in order to achieve better performance. But still there is a non-negligible deviation inmeasurement within different tries and compared to the data we retrieve from hospital.This study, inspired by previous work, aims to further investigate efficient and reliable algorithms forextracting capillary blood velocity. One possible solution is to implement feature based estimation tocalculate the blood flow speed distribution automatically, point by point along the middle line oftargeting blood vessel. We inherit the idea of generating motion vectors from Optic Flow algorithmwhich has the best accuracy performance in vehicle identification domain. But original optic flowalgorithm makes the system too sophisticated and time consuming. Moreover, its two required basicrules may not stand during the blood flow velocity detection. So a customized feature basedestimation is brought up here and supposed to be a practicable method for analysis not only inaccuracy but also in efficiency. Moreover, this report also introduces picture shifting, red blood cellmotion, and double windows marking to compare and to confirm the results. Previous work will beused as a reference for the assessment of new algorithms. / Mikroskopiska videobilder av mikrosirkulation har använts vid klinisk diagnos i flera år, och parametrarna erhållna från bilder avslöjar de flesta fysiologiska aktiviteter och kroppsorganisationer. Särskilt är blodflödeshastigheten ett av viktiga index, som återspeglar tillståndet för mikrosirkulation och gör betydande märken vid diagnosen.För att mäta kapillärblodshastighet har en mängd metoder och instrument studerats och utvecklats. Baserat på mätformatet kan mikroskopimetoder som används allmänt grupperas i två kategorier. Ett direkt sätt använder mikroskopisk bildteknologi för visualisering. Det andra sättet använder assistentmetoder som laserbelysning [1] eller märkning av RBC med fluoresceinisotiocyanat [2]. I tidigare studier har fyra metoder (Direct Observation Method, Dual-windows Method, Single-Window Method, Optical Flow Method) studerats och analyserats för att uppnå bättre prestanda. Men det finns fortfarande en icke försumbar avvikelse i mätningen inom olika försök och jämfört med de data vi hämtar från sjukhuset.Denna studie, inspirerad av tidigare arbete, syftar till att ytterligare undersöka effektiva och tillförlitliga algoritmer för att extrahera kapillärblodhastighet. En möjlig lösning är att implementera funktionsbaserad uppskattning för att beräkna blodflödeshastighetsfördelningen automatiskt, punkt för punkt längs mittlinjen för riktad blodkärl. Vi ärver idén att generera rörelsesvektorer från Optic Flow-algoritmen som har den bästa noggrannhetsprestanda inom fordonsidentifieringsdomän. Men den ursprungliga optiska flödesalgoritmen gör systemet för sofistikerat och tidskrävande. Dessutom kanske dess två nödvändiga grundregler inte gäller under detektionen av blodflödeshastighet. Så en anpassad funktionsbaserad uppskattning tas upp här och antas vara en genomförbar metod för analys inte bara i noggrannhet utan också i effektivitet. Dessutom introducerar detta papper också bildförskjutning, rörelse av röda blodkroppar och dubbla fönstermarkeringar för att jämföra och bekräfta resultaten. Tidigare arbete kommer att användas som referens förbedömning av nya algoritmer.

This dissertation is a concise examination of the complete obverse manuscript (document 1) of the pre-Hispanic pictogram screen-fold painted by the Mixtec Indians of Oaxaca. The study begins with the historiography of Native American Mexican screen-fold books as related by the first historian of the New World, Peter Martyr d’Anghera, in his De orbe novo and proceeds through major authors from the early twentieth century to present day. The nature of “native” history is explored as is the nature of pictogram narrative history. The superficial narrative structure of Codex Zouche-Nuttall, document 1 is then defined and interpretative reading techniques employed in this dissertation are applied to it. The codex document 1 contents (pages 1-41) are then listed in detail by section, structure, personnel, events, and native dates corresponded with the European calendar, this latter in so far as is possible. This definition explicates each of three bifurcated sections of the document, each section consisting of a story plus genealogy or genealogies. Additionally, essays on codex contents are provided to further elaborate these divisions of study within Codex Zouche-Nuttall document 1. These essays explore certain mysterious parts of the stories, as in the case of the Ladies Three Flint and the Four Lords from Apoala. Inferences are made from codex text regarding Postclassic Period Mixtec social organization via both political structure and religion. The end result is a concise elaboration and explanation of the entire document. / text

La technologie des microarrays demeure à ce jour un outil important pour la mesure de l'expression génique. Au-delà de la technologie elle-même, l'analyse des données provenant des microarrays constitue un problème statistique complexe, ce qui explique la myriade de méthodes proposées pour le pré-traitement et en particulier, l'analyse de l'expression différentielle. Toutefois, l'absence de données de calibration ou de méthodologie de comparaison appropriée a empêché l'émergence d'un consensus quant aux méthodes d'analyse optimales. En conséquence, la décision de l'analyste de choisir telle méthode plutôt qu'une autre se fera la plupart du temps de façon subjective, en se basant par exemple sur la facilité d'utilisation, l'accès au logiciel ou la popularité. Ce mémoire présente une approche nouvelle au problème de la comparaison des méthodes d'analyse de l'expression différentielle. Plus de 800 pipelines d'analyse sont appliqués à plus d'une centaine d'expériences sur deux plateformes Affymetrix différentes. La performance de chacun des pipelines est évaluée en calculant le niveau moyen de co-régulation par l'entremise de scores d'enrichissements pour différentes collections de signatures moléculaires. L'approche comparative proposée repose donc sur un ensemble varié de données biologiques pertinentes, ne confond pas la reproductibilité avec l'exactitude et peut facilement être appliquée à de nouvelles méthodes. Parmi les méthodes testées, la supériorité de la sommarisation FARMS et de la statistique de l'expression différentielle TREAT est sans équivoque. De plus, les résultats obtenus quant à la statistique d'expression différentielle corroborent les conclusions d'autres études récentes à propos de l'importance de prendre en compte la grandeur du changement en plus de sa significativité statistique. / Microarrays remain an important tool for the measurement of gene expression, and a myriad of methods for their pre-processing or statistical testing of differential expression has been proposed in the past. However, insufficient and sometimes contradictory evidence has prevented the emergence of a strong consensus over a preferred methodology. This leaves microarray practitioners to somewhat arbitrarily decide which method should be used to analyze their data. Here we present a novel approach to the problem of comparing methods for the identification of differentially expressed genes. Over eight hundred analytic pipelines were applied to more than a hundred independent microarray experiments. The accuracy of each analytic pipeline was assessed by measuring the average level of co-regulation uncovered across all data sets. This analysis thus relies on a varied set of biologically relevant data, does not confound reproducibility for accuracy and can easily be extended to future analytic pipelines. This procedure identified FARMS summarization and the TREAT gene ordering statistic as algorithms significantly more accurate than other alternatives. Most interestingly, our results corroborate recent findings about the importance of taking the magnitude of change into account along with an assessment of statistical significance.