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L'estimation de paramètres génétiques est un problème important dans le domaine de la génétique mathématique et statistique. Il existe plusieurs méthodes s'attaquant à ce problème. Certaines d'entre elles utilisent la méthode du maximum de vraisemblance. Celle-ci peut être calculée à l'aide des équations exactes de Griffiths-Tavaré, équations de récurrence provenant du processus de coalescence. Il s'agit alors de considérer plusieurs histoires possibles qui relient les données de l'échantillon initial de séquences d'ADN à un ancêtre commun. Habituellement, certaines des histoires possibles sont simulées, en conjonction avec l'application des méthodes Monte-Carlo. Larribe et al. (2002) utilisent cette méthode (voir chapitre IV). Nous explorons une nouvelle approche permettant d'utiliser les équations de Griffiths-Tavaré de façon différente pour obtenir une estimation quasi exacte de la vraisemblance sans avoir recours aux simulations. Pour que le temps de calcul nécessaire à l'application de la méthode demeure raisonnable, nous devons faire deux compromis majeurs. La première concession consiste à limiter le nombre de recombinaisons permises dans les histoires. La seconde concession consiste à séparer les données en plusieurs parties appelées fenêtres. Nous obtenons ainsi plusieurs vraisemblances marginales que nous mettons ensuite en commun en appliquant le principe de vraisemblance composite. À l'aide d'un programme écrit en C++, nous appliquons notre méthode dans le cadre d'un problème de cartographie génétique fine où nous voulons estimer la position d'une mutation causant une maladie génétique simple. Notre méthode donne des résultats intéressants. Pour de très petits ensembles de données, nous montrons qu'il est possible de permettre un assez grand nombre de recombinaisons pour qu'il y ait convergence dans la courbe de vraisemblance obtenue. Aussi, il est également possible d'obtenir des courbes dont la forme et l'estimation du maximum de vraisemblance sont similaires à celles obtenues avec la méthode de Larribe et al. Cependant, notre méthode n'est pas encore applicable dans son état actuel parce qu'elle est encore trop exigeante en termes de temps de calcul. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Équations exactes de Griffiths-Tavaré, Paramètres génétiques, Processus de coalescence, Vraisemblance composite.

Dans ce mémoire, nous présentons une nouvelle méthode de cartographie génétique fine ayant comme particularité de pouvoir être utilisée dans le cadre de modèles génétiques complexes. Nous présentons tout d'abord quelques concepts de génétique et de statistique génétique, avec une emphase particulière sur le processus de coalescence qui est à la base de notre travail. Par la suite, trois méthodes de cartographie génétique déjà existantes sont présentées ; notre nouvelle méthode contient des éléments de chacune d'entre elles. Nous décrivons ensuite la nouvelle méthode proposée dans ce mémoire. Finalement, nous testons notre nouvelle approche à l'aide de simulations; nous comparons par la suite les résultats obtenus avec notre méthode à ceux obtenus par des tests d'association classiques, et par deux des trois méthodes présentées au début du mémoire. Les résultats nous laissent croire que notre méthode est performante autant dans des cas de modèles génétiques simples que complexes, contrairement à la plupart des méthodes existantes. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : cartographie génétique, processus de coalescence, arbre de recombinaison ancestral, arbre partiel, distribution proposée, fonction de pénétrance.

Solid state ¹H MAS NMR spectroscopy was used to investigate the temperature and hydration dependance of water and hydroxyl proton spectra of hydrated mesoporous MCM-41. The NMR spectra show a complex peak structure, with hydroxyl proton resonances seen in dry MCM-41 disappearing as water is introduced into the pores, and new peaks appearing representing water and hydrated silanol groups. Until now the assignment of these peaks was unclear and the consensus was that magnetization exchange played an important role in the coalescence of the various peaks which appear in the spectra. It was found recently that magnetization exchange is not necessary to produce the spectral featured observed [Niknam, M., M.Sc. Thesis, University of Waterloo (2010)]. In the present study a simplified model, based on chemical shift averaging by the making and breaking of hydrogen bonds as water undergoes rotational motion and translational self-diffusion on the pore surface, has been developed to explain the NMR spectral results. The model is able to reproduce the experimental ¹H MAS NMR spectra for all hydrations and temperatures studied. For the first time, definitive spectral assignments for all hydroxyl and water protons in the sample has been achieved. Spectral features arising due to temperature change have been explained by using the known result that the proton chemical shift of a hydrogen atom involved in hydrogen bonding varies linearly with temperature. Furthermore, it is reported for the first time, that with increasing hydration, water molecules begin to favour forming two hydrogen bonds to the surface. This may represent the first step in the pore filling process.

Abstract The present thesis focused on the synthesis and phase transformation of tohdite and alumina via static compression of gels at high temperature-pressures and dynamic laser ablation condensation of metal target under oxygen background gas. In part I, hydrous Al2O3-TiO2 (78:22 in molar ratio) gel was fired at various PT conditions using a piston-cylinder apparatus and identified by XRD, FTIR, optical microscopy and electron microscopy. Below 675oC, the sample remained amorphous at ambient pressure, yet transformed at 1.5 kbar to Ti-doped tohdite, which is elongated along the crystallographic c-axis, with well-developed (0001) base and {10 0} faces. Tohdite has a significant water/hydroxy content and is therefore susceptible to pore coalescence parallel to the basal layer upon electron dosage. Tohdite also contains Ti4+ up to 3 at.%, which replaces Al3+ in tetrahedral and/or octahedral sites to form superstructures and defect microstructures. In contrast, a higher T-P condition (above 675oC and 8 kbar) caused the formation of more stable Ti-doped corundum, which is hexagonal-rhombohedral crystal form and in epitaxial association with rutile nuclei. Ti-doped tohdite and corundum shed light on a sol-gel route for their occurrence in peraluminous metamorphic rock. The nanoporous and nanodelaminated tohdite may have potential catalytic applications (Part I). In part II, amorphous Al2O3 nanocondensates were synthesized via very energetic Nd-YAG laser pulse irradiation of oxygen-purged Al target for a very rapid heating/cooling effect. The nanocondensates above a critical diameter of 20 nm were phase separated as

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The tumbling tip vortex effect of a reduced-scale, 1 m diameter, four-bladed rotor during hover is studied using vortex methods, combined with a center of mass analysis approach. Measurements of all three components of the velocity field are acquired using a stereo PIV system synchronized to capture up to 500 degrees of vortex age, with 10 degree wake age offsets, during hover conditions. The nominal operating condition of the rotor is at a rotational rate of 1520RPM, corresponding to ReC = 248,000 with a chord length of 58.5mm. The rotor is operated with a pitch of 7.2± 0.5 degrees and a CT/sigma of 0.045. The far wake vortex tumbling phenomenon is captured and described. It is shown that tip vortices from two blades tumble through approximately 90 degrees of rotation before they coalesce. It is also seen that the constituent parent vortices do not combine to create a stronger daughter vortex as was previously thought to happen. Instead, the merged vortex has a lower large-radius circulation than either of its parent vortices. An accurate characterization and prediction of the trajectory of the far wake vortex tumbling can enhance the ability to predict and alleviate the resuspension of particles during brownout as well as provide a database for far wake validation of CFD codes. / text

Solid state ¹H MAS NMR spectroscopy was used to investigate the temperature and hydration dependance of water and hydroxyl proton spectra of hydrated mesoporous MCM-41. The NMR spectra show a complex peak structure, with hydroxyl proton resonances seen in dry MCM-41 disappearing as water is introduced into the pores, and new peaks appearing representing water and hydrated silanol groups. Until now the assignment of these peaks was unclear and the consensus was that magnetization exchange played an important role in the coalescence of the various peaks which appear in the spectra. It was found recently that magnetization exchange is not necessary to produce the spectral featured observed [Niknam, M., M.Sc. Thesis, University of Waterloo (2010)]. In the present study a simplified model, based on chemical shift averaging by the making and breaking of hydrogen bonds as water undergoes rotational motion and translational self-diffusion on the pore surface, has been developed to explain the NMR spectral results. The model is able to reproduce the experimental ¹H MAS NMR spectra for all hydrations and temperatures studied. For the first time, definitive spectral assignments for all hydroxyl and water protons in the sample has been achieved. Spectral features arising due to temperature change have been explained by using the known result that the proton chemical shift of a hydrogen atom involved in hydrogen bonding varies linearly with temperature. Furthermore, it is reported for the first time, that with increasing hydration, water molecules begin to favour forming two hydrogen bonds to the surface. This may represent the first step in the pore filling process.

No description available.

This dissertation describes experiments on drop dynamics. It is split into two main parts: The first investigates the breakup of liquid during the impact of a drop on a pool surface, with focus on the smallest and fastest splashed satellite droplets. The second part studies the much slower coalescence of two minute water droplets in oil inside a micro-channel, with applications to separation of water droplets from crude oil emulsions. First, we study drop-on-liquid impacts in high-speed experiments with extreme time and spatial resolutions using up to 5 million frames-per-second video imaging. This is used to identify and explain two primary mechanisms which produce the smallest and fastest splashed secondary droplets, i.e. ejecta sheets and singular jets. Using a novel 25-m-tall vacuum tube we generate very large impact velocities, to reach regimes in parameter-space never studied before. During the earliest stage of the impact a fast-moving horizontal ejecta sheet emerges from the neck between drop and pool. The breakup of this sheet forms a myriad of micron-size droplets. The ejecta bending is dominated by air resistance, which we investigate under reduced ambient pressures and successfully model based on Bernoulli suction which pulls down the ejecta to hit the pool surface. The ejecta can initially bend up or down depending on the relative viscosities of the drop and pool, bending up if the pool is less viscous. Singular jets are produced by the collapse of drop-impact craters for deep pools, when a dimple forms at the bottom of the crater focusing the energy into a micron-sized region, with jetting velocities over 100 m/s. We use Gerris to study the fine details, obscured in the experiments. In the second part, we study the coalescence of water droplets inside an oil emulsion, developing an empirical relation between the coalescence interaction time tc and the modified shear-rate. This is done by tracking 3-D drop trajectories inside a microchannel, with two perpendicular high-speed cameras. For droplets in crude oil, we implement near-infrared visualization in an innovative device to quantify demulsifier efficiency, using mono-disperse micro-droplets.