Vocal Function Exercises (VFEs) is a well-known treatment program that consists of four exercises, in which the first and fourth tasks require maximally sustained phonation. However, the active ingredients responsible for treatment efficacy are still unknown. The primary purpose of this investigation was the explore the effects of maximally sustained phonation on the VFE outcome measure of maximum phonation time (MPT) in individuals between the ages of 18-40 with normal voice. Participants were randomized into three experimental groups that completed VFEs for six weeks. The baseline group sustained tasks one and four for as long as was achieved at the baseline session; The three-week group sustained the exercises for as long as possible the first three weeks, then to their three-week MPT average for the remaining three weeks of the program; The standard group maximally sustained phonation for all six weeks. Results indicated significant improvement in percent to MPT goal attainment in the standard group and three-week group. The baseline group did not result in significant change. Including maximally sustained phonation throughout the course of VFEs is essential to producing substantial improvements in voice production, in terms of percent to MPT goal.

L’objectif général de cette thèse était de tester l’efficacité d’un entraînement exécutif ainsi que de tester les transferts des bénéfices de cet entraînement sur d’autres fonctions cognitives notamment la mémoire épisodique au niveau comportemental et électrophysiologique chez des adultes âgés. Pour cela, des effets test-retest ont été observés lors de la passation d’un même test de façon consécutive. Ainsi, la création de nouveaux tests pour confectionner le programme d’entraînement a été nécessaire pour ne pas avoir ces effets tests re-tests lors de la passation des pré-tests et des post-tests. Les entraînements exécutifs ont permis l’amélioration du fonctionnement exécutif mais aussi l’amélioration de la vitesse de traitement, et ces bénéfices ont permis l’annulation des effets d’âge dans le groupe entraîné sur une fonction exécutive : la mise à jour de la mémoire de travail. De plus, des effets de transfert ont été obtenus sur l’utilisation stratégique lors de l’encodage d’information en mémoire épisodique. Plus précisément, les adultes âgés entraînés utilisaient plus de stratégies d’encodages efficaces (encodage profond de type imagerie mentale ou phrase) après l’entraînement exécutif et l’utilisation de ces stratégies était plus efficace. Au niveau cérébral, l’entraînement exécutif semble engendrer des processus de spécialisation cérébrale se traduisant par une diminution de l’activité cérébrale de certaines zones cérébrales. Ce travail de thèse incite le développement de programmes d’entraînement des fonctions exécutives qui semblent permettre des effets de transfert à des tâches non entraînées et ces bénéfices semblent aussi modifier le fonctionnement cérébral, ce qui suppose un effet plus durable. Ceci confirme l’idée qu’un environnement stimulant cognitivement est en lien avec de bonnes capacités cognitives et contribue à un vieillissement réussi / The main objective of this thesis was to test the efficiency of an executive training program and the transfer effects of this program on other cognitive functions, in particular episodic memory strategies and performance. The present work was based on behavioral and electrophysiological data. Practice effects of executive tests have been first tested in young and older adults. Two tests have been practiced across ten practice sessions, and the results showed that the executive functions scores increased after practice, more for the older adults than for the younger ones. In order to develop an executive training program requiring several different tests, we have created new executive tests. The psychometric validity of these tests has been verified and confirmed. These tests have been used for our executive program. Thus, if training effects appeared following this program, they will not be due to the practice of a unique test. Eight sessions of executive stimulation with our new tests have allowed older adults increasing their executive functioning, measured by tests which were different from those employed in the training program (near transfer effects). Other cognitive functions were also improved, as processing speed and episodic memory. For the first time in the literature, far transfer effect have been found memory strategy efficiency and memory performance. More especially, the older adults trained group used more efficient memory strategies (mental imagery or making sentence with the words to be learnt) after the executive training program, and these strategies were more efficient to recall the words. Thus, the memory performance was increased in this group, in comparison the older adults group who did not participate to the training program. At a cerebral level, the executive training seems to decrease the duration of the cerebral activity for the same memory task. However, these results must to be taken with caution and require further analyses to be interpreted correctly. The results of this thesis encourages the development of training programs for executive functions which allows the transfer effects to untrained tasks. These benefits also appear to modify the brain functioning, which implies a longer lasting benefit effect. This work supports the idea that a cognitively stimulating environment is in line with higher cognitive abilities and contributes to successful aging

This thesis explores the problems of fitting antedependence (AD) models and partial antecorrelation (PAC) models to continuous non-Gaussian longitudinal data. AD models impose certain conditional independence relations among the measurements within each subject, while PAC models characterize the partial correlation relations. The models are parsimonious and useful for data exhibiting time-dependent correlations. Since the relation of conditional independence among variables is rather restrictive, we first consider an autoregressively characterized PAC model with independent asymmetric Laplace (ALD) innovations and prove that this model is an AD model. The ALD distribution previously has been applied to quantile regression and has shown promise for modeling asymmetrically distributed ecological data. In addition, the double exponential distribution, a special case of the ALD, has played an important role in fitting symmetric finance and hydrology data. We give the distribution of a linear combination of independent standard ALD variables in order to derive marginal distributions for the model. For the model estimation problem, we propose an iterative algorithm for the maximum likelihood estimation. The estimation accuracy is illustrated by some numerical examples as well as some longitudinal data sets. The second component of this dissertation focuses on AD multivariate skew normal models. The multivariate skew normal distribution not only shares some nice properties with multivariate normal distributions but also allows for any value of skewness. We derive necessary and sufficient conditions on the shape and covariance parameters for multivariate skew normal variables to be AD(p) for some p. Likelihood-based estimation for balanced and monotone missing data as well as likelihood ratio hypothesis tests for the order of antedependence and for zero skewness under the models are presented. Since the class of skew normal random variables is closed under the addition of independent standard normal random variables, we then consider an autoregressively characterized PAC model with a combination of independent skew normal and normal innovations. Explicit expressions for the marginals, which all have skew normal distributions, and maximum likelihood estimates of model parameters, are given. Numerical results show that these three proposed models may provide reasonable fits to some continuous non-Gaussian longitudinal data sets. Furthermore, we compare the fits of these models to the Treatment A cattle growth data using penalized likelihood criteria, and demonstrate that the AD(2) multivariate skew normal model fits the data best among those proposed models.

This thesis considers statistical issues in source localization from the received signal strength (RSS) measurements at sensor locations, under the practical assumption of log-normal shadowing. Distance information of source from sensor locations can be estimated from RSS measurements and many algorithms directly use powers of distances to localize the source, even though distance measurements are not directly available. The first part of the thesis considers the statistical analysis of distance estimation from RSS measurments. We show that the underlying problem is inefficient and there is only one unbiased estimator for this problem and its mean square error (MSE) grows exponentially with noise power. Later, we provide the linear minimum mean square error (MMSE) estimator whose bias and MSE are bounded in noise power. The second part of the thesis establishes an isomorphism between estimates of differences between squares of distances and the source location. This is used to completely characterize the class of unbiased estimates of the source location and to show that their MSEs grow exponentially with noise powers. Later, we propose an estimate based on the linear MMSE estimate of distances that has error variance and bias that is bounded in the noise variance.

Semicontinuous data consist of a combination of a point-mass at zero and a positive skewed distribution. This type of non-negative data distribution is found in data from many fields, but presents unique challenges for analysis. Specifically, these data cannot be analyzed using positive distributions, but distributions that are unbounded are also likely a poor fit. Two-part models incorporate both the zero values from semicontinuous data and the positive continuous values. In this dissertation, we compare zero-inflated gamma (ZIG) and zero-inflated log-normal (ZILN) two-part models. For both of these models, the probability that an outcome is non-zero is modeled via logistic regression. Then the distribution of the non-zero outcomes is modeled via gamma regression with a log-link for ZIG regression and via log-normal regression for ZILN. In this dissertation we propose tests which combine the two parts of the ZIG and ZILN models in meaningful ways for performing a two group comparison. Then we compare these tests in terms of observed Type 1 error rates and power levels under both correctly specified and misspecified ZIG and ZILN models. Tests falling under two main hypotheses are examined. First, we look at two-part tests which come from a two-part hypothesis of no difference between the two groups in terms of the probability of non-zero values and in terms of the the mean of the non-zero values. The second type of tests are mean-based tests. These combine the two parts of the model in ways related to the overall group means of the semicontinuous variable. When not adjusting for covariates, two tests are developed based on a difference of means (DM) and a ratio of means (RM). When adjusting for covariates, tests using mean-based hypotheses are developed which marginalize over the values of the adjusting covariates. Under the adjusting framework, two ratio of means statistics are proposed and examined, an average of the subject specific ratio of means (RMSS) and a ratio of the marginal group means (RMMAR). Simulations are used to compare Type 1 error and power for these tests and standard two group comparison tests. Simulation results show that when ZIG and ZILN models are misspecified and the coefficient of variation (CoV) and/or sample size is large, there are differences in Type 1 error and power results between the misspecified and correctly specified models. Specifically, when ZILN data with high CoV or sample size are analyzed as ZIG, Type 1 error rates are prohibitively high. On the other hand, when ZIG data are analyzed as ZILN under these scenarios, power levels are much lower for ZILN analyses than for ZIG analyses. Examination of Q-Q plots show, however, that in these settings, distinguishing between ZIG and ZILN data can be relatively straightforward. When the coefficient of variation is small it is harder to distinguish between ZIG and ZILN models, but the differences between Type 1 error rates and power levels for misspecified or correctly specified models is also slight. Finally, we use the proposed methods to analyze a data set involving Parkinson's disease (PD) and driving. A number of these methods show that PD subjects exhibit poorer lane keeping ability than control subjects.

The chief aim in developing radiation treatment plans is to maximise tumour cell kill while minimising the killing of normal cells. The acceptance by a radiation oncologist of a radiation therapy treatment plan devised by the radiation therapist, at present is largely based on the oncologists' previous clinical experience with reference to established patterns of treatment and their clinical interpretation of the dose volume histogram. Some versions of radiotherapy planning computer software now incorporate a function that permits biologically based predictions about the probability of tumour control (TCP) and/or normal tissue complications (NTCP). The biological models used for these probabilities are founded upon statistical and mathematical principles as well as radiobiology concepts. TCP and NTCP potentially offer the capability of being able to better optimise treatments for an individual patient's tumour and normal anatomy. There have been few attempts in the past to correlate NTCPs to actual treatment complications, and the reported complications have generally not shown any significant correlation. Thus determining whether either or both NTCPs and TCPs could be correlated with the observed clinical outcomes of prostate radiotherapy is the central topic of this thesis. In this research, TCPs and NTCPs were prospectively calculated for prostate cancer patients receiving radiation therapy, and subsequently assessed against the clinical results of the delivered treatments. This research was conducted using two different types of NTCP models, which were correlated against observed treatment-induced complications in the rectum and bladder. The two NTCP models were also compared to determine their relative efficacy in predicting the recorded toxicities. As part of this research the refinement of some of the published bladder parameters required for NTCP calculations was undertaken to provide a better fit between predicted and observed complication rates for the bladder wall which was used in this research. TCPs were also calculated for each patient using the best available estimate of the radiosensitivity of the prostate gland from recent research. The TCP/NTCP data was analysed to determine if any correlations existed between the calculated probabilities and the observed clinical data. The results of the analyses showed that a correlation between the NTCP and a limited number of toxicities did occur. Additionally the NTCP predictions were compared to existing parameters and methods for radiotherapy plan evaluation - most notably DVHs. It is shown that NTCPs can provide superior discriminatory power when utilised for prospective plan evaluation. While the TCP could not be correlated with clinical outcomes due to insufficient follow-up data, it is shown that there was a correlation between the TCP and the treatment technique used.

Ce travail qui s'inscrit dans la problématique de la théorie des ambiances se propose, à travers l'approche d'un espace dédié à la pathologie mentale, de s'attacher aux rôles des ambiances intérieures de structures spécialisées dans l'accueil d'enfants présentant des troubles psychiques. Sur trois hôpitaux, la méthode comprend de longues campagnes d'observations ethnographiques des enfants dans leur milieu d'accueil, des relevés architecturaux et des mesures d'ambiance ainsi que diverses discussions avec les professionnels touchant à notre sujet. L'analyse s'est attachée, premièrement, aux conduites spatiales, sociales et affectives de ces enfants par rapport à leur environnement, deuxièmement, à dégager l'émergence de certains facteurs ambiants et combinaisons de facteurs participant aux conduites usagères et à la formation des ambiances situées. Les résultats intéressent donc, d'un point de vue architectural, une aide à la programmation et à la conception d'espaces pédopsychiatriques à partir de critères pertinents, comme par exemple, la lisibilité des espaces, la solidité de l'enveloppe spatiale, l'aménagement de transitions à différentes échelles du projet. Une autre retombée est l'aide à la communication entre la maîtrise d'ouvrage, les professionnels de la santé mentale et la maîtrise d'oeuvre. Plus largement, sur l'hypothèse d'une relation non antithétique entre normal et pathologique, cette recherche participe à l'affinement de nos connaissances sur la relation sensori-motrice que tout sujet entretient avec son environnement et sur la perception qu'il a d'un espace par la convocation et la combinaison de différentes modalités sensibles.

La modélisation géométrique d'un problème de gestion de la fabrication des mélanges (faisabilité simultanée de deux mélanges) fait apparaître des polytopes nouveaux résultant de la somme de triangles particuliers qui dans ce contexte sont appelés convexes de 2-mélanges. De façon plus générale, la somme de triangles peut être considérée comme la généralisation des zonotopes (somme de segments). De ce point de vue, l'étude menée ici fait apparaître que la propriété de zone associée à un segment du zonotope se généralise à trois demi-zones associées à chaque triangle; et que la complexité combinatoire (nombre de faces du polytope), par rapport au nombre de sommandes, est du même ordre de grandeur que celle des zonotopes. On traite également le problème de la construction de tels polytopes, des algorithmes optimaux en temps sont proposés. Concernant le problème particulier des mélanges, le premier cas non trivial est celui de mélanges à trois composantes qui nous place en dimension 6. L'appartenance d'un point au convexe de 2-mélanges détermine la faisabilité simultanée des mélanges. Les facettes de ce polytope sont décrites, en détail, dans le cas de la dimension 6, dans le but d'obtenir des conditions de faisabilité des deux mélanges. Le problème de la décomposition de polytopes en somme de Minkowski de polytopes plus simples est exposé, ainsi que les principaux résultats existant.

Dans ce travail de thèse, on s'est intéressé aux changement des propriétés électroniques en fonction du dopage de couches minces épitaxiées des composés supraconducteurs Bi2Sr2Can-1CunOy : phase Bi2Sr2CaCu2Oy (Tcmax=80 K) et Bi2Sr1.6La0.4CuOy (Tcmax=30 K) respectivement avec un et deux plans CuO2. Le changement des propriétés électroniques le plus étonnant se passe dans la région sous-dopée du diagramme de phase où un pseudogap s'ouvre à l'état normal dans le spectre des excitations électroniques. La mesure de la résistivité R(T), de l'effet Hall RH(T) et de la magnétorésistance MR(T,H) sur ces deux phases ayant le même réservoir de charges ont permis une étude directe de l'effet de pseudogap en fonction du nombre de plans CuO2 et de la température critique. Cet effet se manifeste par une déviation de R(T) par rapport à la loi linéaire se produisant au-dessous d'une température caractéristique T* et il est observé dans les deux phases. Toutes les courbes peuvent être superposées en fonction de T/T* sur une courbe unique, différente pour chaque phase, ce qui reflète une différence d'amplitude de l'effet de pseudogap dans R(T) d'un facteur 2, relié au nombre différent de plan CuO2. Par contre la température d'ouverture du pseudogap T* a le même ordre de grandeur dans les deux phases. Sa disparition rapide au voisinage de l'état optimal semble exclure une relation entre T* et Tc. De plus, l'existence d'un point critique au voisinage de l'état optimal est discutée ainsi que la corrélation possible entre les propriétés supraconductrices et les propriétés de l'état normal.

<p>Crystallographic and spectroscopic studies have been performed of structures, coordination and chemical bonding for series of trivalent metal ions solvated by two oxygen-coordinating solvents, water and dimethyl sulfoxide (DMSO). The hydrated scandium(III) and lanthanoid(III) ions, La to Lu, are surrounded by tricapped trigonal prisms of aqua ligands in the isomorphous series of trifluoromethanesulfonates, [M(H₂O)_n](CF₃SO₃)₃. For the smallest ions, M = Er, Tm, Yb, Lu, Sc, the hydration numbers decrease, <i>n</i> = 8.96(5), 8.8(1), 8.7(1), 8.5(1), 8.0(1), respectively, with decreasing size of the ion. The crystal structures at ambient temperature indicate randomly distributed vacancies of the capping oxygen atoms, and ²H solid-state NMR of the diamagnetic [M(H₂O)_n](CF₃SO₃)₃, M = Sc, Lu, Y and La compounds revealed increasing mobility of the water ligands in the coordination sphere with increasing temperature, also for the fully nonahydrated La^III and Y^III ions. The stretching force constants of the Ln-O bonds, evaluated from vibrational spectroscopy, increased from 0.81 to 1.16 N cm^-1 for the Ln-6O trigonal prism in a smooth correlation with the bond distances from La to Lu. For the capping Ln-3O bonds the increase from 0.49 to 0.65 N cm^-1 reflects the increased ligand-ligand repulsion with decreasing ion size. This is also the reason for the water deficiency of the Er, Tm, Yb, Lu and Sc salts, and for [Sc(H₂O)_8.0](CF₃SO₃)₃ the repulsion induced a phase transition at about 185 K that, by low temperature crystallography, was found to distort the coordination of water molecules toward a monocapped trigonal prism around the scandium(III) ion.</p><p>All crystal structures of the octakis(dimethyl sulfoxide)lanthanoid(III) iodides comprise discrete [Ln(dmso)₈]³⁺ complexes surrounded by iodide ions. The lanthanum(III) and praseodymium(III) compounds crystallize in the orthorhombic space group <i>Pbca</i> with more efficient packing than for the heavier and smaller ions in the lanthanoid series, which crystallize in the monoclinic space group <i>P2</i>₁/<i>n</i>. The group 13 metal ions, aluminium(III), gallium(III), indium(III), thallium(III), and also scandium(III) of group 3, form crystalline hexakis(dimethyl sulfoxide) solvates in the space group <i>R</i> 3, with octahedral MO₆ coordination entities, which are increasingly compressed along one threefold axis for increasing ionic size. EXAFS measurements on the solvated ions display similar M-O bond distances in dimethyl sulfoxide solution as in the solid solvates. For all the solid dimethyl sulfoxide solvates the strength and nature of the metal-oxygen bond has been evaluated by normal coordinate analysis of vibrational spectra, and correlated with the S-O stretching vibrational mode.</p><p>Distortions from regular octahedral six coordination are discussed for the hydrated isoelectronic soft mercury(II) and thallium(III) ions in the solid bisaquamercury(II) and trisaquatallium(III) trifluoromethanesulfonates, in terms of pseudo Jahn-Teller effects (PJTE). Mercury(II), generally more strongly influenced by PJTE distortions, displays a 2 + 4 Hg-O coordination forming chains that are held together in sheets by hydrogen bonds and in layers by van der Waals interactions, which explain the fragile structure of the crystals.</p>