Les initiatives informelles dans le Sud partagent-elles une logique capitaliste ou représentent-elles les germes d’une économie solidaire ? Le cas de Santiago du Chili

Conference (2013, June 08)

Mise en charge immédiate en zone esthétique avec un pilier zircone préformé

Conference (2013, June 08)

Proposition de nouveaux indices de détection de patrons de réponses inappropriés dans le contexte des enquêtes et des épreuves d’évaluation des apprentissages

Conference (2013, June 07)

Il n’est pas rare de voir des étudiants répondre de façon inappropriée à une épreuve d’évaluation comportant des items à réponses choisies. Par exemple, certains individus peuvent tricher alors que ... [more ▼]

Il n’est pas rare de voir des étudiants répondre de façon inappropriée à une épreuve d’évaluation comportant des items à réponses choisies. Par exemple, certains individus peuvent tricher alors que d’autres peuvent tenter de se sous-classer intentionnellement à un examen. Plusieurs approches ont été développées pour faire la détection de ce type d’étudiants. À ce jour, l’approche la plus prometteuse est l’utilisation d’indice de détection de type person‐fit (Meijer et Sijtsma, 2001). L’indice de détection lz (Drasgow, Levine et Williams, 1985) est fort probablement le plus utilisé et le plus connu d’entre tous. Malheureusement, cet indice est fortement affecté par le fait que l’habileté des étudiants est estimée et non pas réelle ; ce qui peut biaiser son calcul (Molenaar et Hoijtink, 1990). Pour pallier ce problème, Snijders (2001) a proposé une correction qui permet de diminuer considérablement le biais associé à la moyenne et à la variance de l’indice lz. Dans le cadre de notre projet doctoral, nous nous inspirerons de la suggestion de Snijders (2001) pour corriger deux autres indices de détection de patrons de réponses inappropriés : l’infit mean square (u) et l’outfit mean square (w). À cette fin, nous utiliserons une approche monte carliste afin d’investiguer plus en détails l’erreur de type 1 et la puissance de ces autres indices. Nos résultats préliminaires, que nous présenterons lors de cette communication, montrent que ces autres indices corrigés semblent eux aussi plus efficaces que leur version traditionnelle sans correction. [less ▲]

Actualité des manuscrits et études génétiques de Sartre : les années 1950

Conference (2013, June 07)

Multivariate statistics to understand the geochemical processes induced by groundwater pollution Multi-scale applying

Conference (2013, June 07)

Different hydrogeochemical approaches (classical diagrams, spatial distribution maps, geochemical equations and multivariate statistics) are combined to obtain a global understanding of the ... [more ▼]

Different hydrogeochemical approaches (classical diagrams, spatial distribution maps, geochemical equations and multivariate statistics) are combined to obtain a global understanding of the hydrogeochemical processus at regional and at local scale. [less ▲]

Procédés et enjeux de l'écriture polémique dans le dossier épistolaire anti-adoptianiste du concile de Francfort (794)

Conference (2013, June 06)

Nous proposons une relecture à deux voix – historico-littéraire – des pièces du dossier épistolaire de Francfort attribué à Alcuin. Nous envisagerons les stratégies littéraires et oratoires mises en ... [more ▼]

Nous proposons une relecture à deux voix – historico-littéraire – des pièces du dossier épistolaire de Francfort attribué à Alcuin. Nous envisagerons les stratégies littéraires et oratoires mises en œuvres par Alcuin au nom des évêques francs, d’une part, et de Charlemagne, de l’autre, pour tenter de ramener l’épiscopat espagnol dans le giron romain. Nous tenterons d’affiner notre lecture des positions de chacun, perçues à travers le prisme des mots du diacre anglo-saxon. La confrontation de ces lettres synodales à celles qui ont été envoyées par les évêques espagnols, emmenés par l’archevêque Élipand de Tolède, devrait nous permettre de nourrir une réflexion sur le rôle, l’importance et la puissance stylistique du genre épistolaire, hérité de l’Antiquité, dans deux foyers importants de haute culture de l’époque – la péninsule ibérique et le monde insulaire – ainsi que sur l’impact de cette querelle épistolaire dans le processus de re-développement du genre dans le cadre de la renaissance carolingienne. [less ▲]

Intérêt de l'épidémiologie et des modèles animaux expérimentaux dans l'étude des valvulopathies en cardiologie humaine et équine

Doctoral thesis (2013)

Valvular regurgitations are one of the most common causes of cardiac diseases in humans and in domestic animals. Clinical studies, epidemiological studies, and animal experimental models have been ... [more ▼]

Valvular regurgitations are one of the most common causes of cardiac diseases in humans and in domestic animals. Clinical studies, epidemiological studies, and animal experimental models have been developed to test new diagnostic and therapeutic techniques. Electrocardiography, Doppler echocardiography, angiography, magnetic resonance imaging (MRI) and computed tomography are currently used in clinical practice for diagnosis and prognosis. Medical management and, in humans, surgical treatments can increase life expectancy and improve quality of life of cardiac patients. In horses, cardiac clinical abnormalities including murmurs and arrhythmias are relatively common while the prevalence of clinically significant cardiac diseases is low. However, investigation of these with ECG and Doppler echocardiography is recommended as even mild cardiac abnormalities may lead to significant cardiac disease and cause poor performance in sport horses. To our knowledge, risk factors for several cardiac diseases have been suspected in equids. Few have been statistically demonstrated in a large equine population, since most studies about cardiac murmurs or arrhythmias concerned only racehorses. The first aim of this research work was to perform an epidemiological study in a large equine population to describe risk factors for various cardiac diseases. The prevalence of main cardiac diseases in the studied population was in accordance with previously described prevalence as mitral regurgitation (MR), atrial fibrillation (AF), aortic regurgitation (AR) and tricuspid regurgitation (TR) were the most frequently observed cardiac diseases. Various risk factors of these cardiac diseases were statistically demonstrated: Ageing and male gender appear to predispose to AR, TR appears to affect middle-aged patients, and AF was significantly more common in larger and heavier horses. Moreover MR was an important cardiac disease since it led to congestive heart failure (CHF) whereas AR was not a direct risk factor for CHF. Functional ischemic MR is one of the main human valvular diseases and is caused by ischemic cardiomyopathy with one or more prior myocardial infarctions involving most commonly the basal posterolateral myocardium of the left ventricle (LV). The therapeutic approach to functional MR is difficult and still controversy as regards the timing and the nature of the treatment. To our knowledge, no percutaneous large animal model of functional MR has been conceptualized. This model would be the first one to allow studying the dynamic component of functional MR. Therefore the second aim of this work was the development of an experimental animal model of functional ischemic MR. Goats appeared as good candidates for the model as they fulfill all requested conditions. They have a body and heart size comparable to that of humans and can be handled easily even during exercise tests. As few publications are available in this species, three first studies were designed to test the repeatability and to establish the reference values of measurements obtained using Two-Dimensional (2D), M-Mode, Pulsed-wave (PW) Doppler and 2D speckle tracking (2DST) echocardiography in unsedated standing adult goats. Standardized echocardiographic protocols were performed three times by the same observer at one day interval on 10 to 12 goats and the intra-observer inter-day repeatability and variability was calculated. 2D and M-Mode echocardiography showed a good inter-day repeatability and a low variability of the cardiac measurements, whereas PW Doppler measurements had a poor inter-day repeatability and a moderate variability. Caprine 2DST parameters demonstrated a poor but acceptable repeatability and a high variability and allowed determination of significant physiologic differences between measurements at rest and after exercise. Then the experimental model of functional ischemic mitral regurgitation induced by a percutaneous approach in goats was developed. This experimental study was conducted in two steps: first, the study of the goat coronary arteries anatomy to determine the best myocardial infarction location to induce ischemic MR in adult Saanen goats and, secondly, the development and the imaging characterization of the goat model of functional ischemic MR. The anatomic pattern of the coronary artery system of the goat was determined using casts made of auto polymerizing resin. Two coronary arteries branches were highlighted from the results of this anatomical study: the left marginal branch (LMB) and the posterior descending branch (PDB) of the left circumflex artery, which could supply the posterolateral wall of the LV. Then myocardial infarction was induced by microcoil embolization of LMB, PDB, or both, under fluoroscopic guidance. The results confirmed that LMB and PDB occlusion produced a large myocardial infarction and an immediate severe functional MR (n=3) unlike only LMB (n=2) or only PDB occlusion (n=2). Mortality rate of this model was high (56%), particularly when LMB and PDB were simultaneously occluded (87,5%). After the myocardial infarction, a complete follow-up was performed in each surviving goat using echocardiographic techniques previously described and MRI. 2DST techniques allowed quantifying LV dysfunction during acute ischemic MR. Quantification of functional MR was performed by Doppler techniques including measurements of the vena contracta width, the effective regurgitant orifice area and the regurgitant volume using the proximal isovelocity surface area method (PISA), and by 2D-echocardiographic technique analyzing the geometrical distortion of the mitral apparatus in mid-systole (tenting area and coaptation distance). Finally, MRI confirmed the location of myocardial ischemia and the presence of functional MR. These findings make this model an interesting alternative to study the pathophysiology of the functional ischemic MR, especially for its dynamic component yielding useful prognostic information. In conclusion, the two major aims of this research were met: the prevalence of various cardiac diseases and their risk factors in a large population of equids were described and an experimental model of functional ischemic mitral regurgitation induced by a percutaneous approach in goats was developed. This model of experimental ischemic MR could be useful to further study the pathophysiology of the functional ischemic MR, especially for its dynamic component and to maximize further treatment in problem patients. Our epidemiologic study confirmed that horses with cardiac murmurs or arrhythmias and presenting demonstrated risk factors, should routinely undergo ECG and Doppler echocardiography to diagnose and to evaluate the severity of any pathological cardiac abnormalities and to identify potential signs of evolution into CHF, including the presence of multiple cardiac diseases and enlargement of the cardiac chambers. [less ▲]

La protection de l’environnement et les installations classées

Conference given outside the academic context (2013)

Les microalgues: un défi énergétique

Scientific conference (2013, June 06)

Les microalgues sont des micro-organismes photosynthétiques dont la culture commerciale en masse est pratiquée depuis les années '60. Les rendements en biomasse de la culture de microalgues sont ... [more ▼]

Les microalgues sont des micro-organismes photosynthétiques dont la culture commerciale en masse est pratiquée depuis les années '60. Les rendements en biomasse de la culture de microalgues sont supérieurs à ceux de cultures traditionnelles, et elle peut s'effectuer sur des terrains impropres à l'agriculture traditionnelle. Les perspectives d'utilisation de la biomasse microalgale pour la production de biocarburants ont suscité d'importants efforts de recherche au cours des années récentes. Les recherches en cours visent à améliorer les souches d'algues utilisables ainsi que différents aspects des procédés de production, de traitement et d'extraction de la biomasse algale afin d'aboutir à moyen terme à un procédé durable et économiquement viable. [less ▲]

Innovative Methodology for the Definition of Design Spaces of Chromatographic Methods

Conference (2013, June 06)

As defined by ICH [1] and FDA, Quality by Design (QbD) stands for “a systematic approach to development that begins with predefined objectives and emphasizes product and process understanding and process ... [more ▼]

As defined by ICH [1] and FDA, Quality by Design (QbD) stands for “a systematic approach to development that begins with predefined objectives and emphasizes product and process understanding and process control, based on sound science and quality risk management”. A risk–based QbD–compliant approach is proposed for the robust development of analytical methods. This methodology based on Design of Experiments (DoE) to study the experimental domain models the retention times at the beginning, the apex and the end of each peak corresponding to the compounds of a mixture and uses the separation criterion (S) rather than the resolution (RS) as a Critical Quality Attribute. Stepwise multiple linear regressions are used to create the models. The estimated error is propagated from the modelled responses to the separation criterion (S) using Monte Carlo simulations in order to estimate the predictive distribution of the separation criterion (S) over the whole experimental domain. This allows finding ranges of operating conditions that will guarantee a satisfactory quality of the method in its future use. These ranges define the Design Space (DS) of the method. In chromatographic terms, the chromatograms processed at operating conditions within the DS will assuredly show high quality, with well separated peaks and short run time, for instance. This Design Space can thus be defined as the subspace, necessarily encompassed in the experimental domain (i.e. the knowledge space), within which the probability for the criterion to be higher than an advisedly selected threshold is higher than a minimum quality level. Precisely, the DS is defined as “the multidimensional combination and interaction of input variables (e.g., material attributes) and process parameters that have been demonstrated to provide assurance of quality” [1]. Therefore, this DS defines a region of operating conditions that provide prediction of assurance of quality rather than only quality as obtained with traditional mean response surface optimisation strategies. For instance, in the liquid chromatography there is a great difference in e.g. predicting a resolution (RS) higher than 1.5 vs. predicting that the probability for RS to be higher than 1.5 (i.e. P(RS> 1.5)) is high. The presentation of this global methodology will be illustrated for the robust optimisation and DS definition of several liquid chromatographic methods dedicated to the separation of different mixtures: pharmaceutical formulations, API and impurities/degradation products, plant extracts, separation of enantiomers, … [less ▲]