Philosophiae Doctor - PhD / There have been a number of attempts to measure the expansion rate of the Universe using age-dating of Luminous Red Galaxies (LRGs). Assuming that stars in LRGs form at the same time, age-dating of two populations of LRGs at different redshifts can provide an estimate of the time different associated with the corresponding redshift interval (dz/dt). This gives a direct estimate of the Hubble parameter H (z) at the average redshift of the two populations. In this thesis, we explore the validity of this method by using two different sets of data. Firstly, we select a homogeneous sample of passively evolving galaxies over 0.10 < z < 0.40 from the Sloan Digital Sky Survey Data Release Seven (SDSS-DR7) catalogue by applying a refined criteria, which is based on absolute magnitude. Secondly, we carry out series of observations on the Southern African Large Telescope (SALT) to obtain spectra of LRGs at two narrow redshift ranges z ' 0.40 and z ' 0.55 in order to calculate the Hubble parameter H(z) at z ' 0.47. We utilise two distinct methods of age-dating including the use of absorption Lick index lines and full spectral fitting on high signal-to-noise galaxy spectra from our sample. By establishing the age-redshift relation of the quiescent, passively evolving galaxies from SDSS, we obtain three improved new observational H(z) data points which are H(z) = 76.8 5.3 km s􀀀1Mpc􀀀1 at z ' 0.28, H(z) = 78.5 6.8 km s􀀀1Mpc􀀀1 at z ' 0.30 and H(z) = 86.3 7.6 km s􀀀1Mpc􀀀1 at z ' 0.32 respectively. We also find another H(z) value of 105 39 km s􀀀1Mpc􀀀1 at z ' 0.47 when age-dating LRGs observed with SALT. Combining all 4 data points with another 25 data points in the literature, we place better constraints on cosmological models and find the matter density parameter to be constrained by m = 0:32+0:05 􀀀0:06 and the Hubble constant to be H0 =68.5 2.4. These results are very consistent with other studies. Through this work, we are able to demonstrate that the cosmic chronometers approach can potentially be used to explore the evolution of the Universe.

It has been shown that the observation of two model types, or mixed-modeling, is more beneficial than watching a single type alone (Andrieux & Proteau, 2013; Robertson, 2015). Furthermore, observing others has been shown to lead to consolidation, however, the distinct behavioural outcomes are different than those following physical practice (Trempe et al., 2011). To date it is unknown, whether the observation of different model types, when interspersed with physical practice, will affect the amount of consolidation that occurs. The purpose of this research was to attempt to replicate the mixed-model benefit and to determine whether a mixed-model observation intervention would affect consolidation processes differentially compared to a single-model type alone. Forty-five university age students were randomly assigned to a mixed-model (MM), unskilled model (UM), or skilled model (SM) observation group. All participants were required to learn a waveform-matching task, in which they used their non-dominant arm to reproduce a waveform as accurately as possible within a goal movement time of 900ms. The experiment comprised three testing sessions. The first session required participants to complete a pretest, where they performed 10 trials of the skill with no knowledge of results (KR) provided. Following this, they did their first acquisition session where they received KR on all trials and performed nine blocks of 10 trials that consisted of six physical practice interspersed with four observation trials. Ten minutes following this session, participants performed an immediate retention test consisting of 10 no KR trials. The next day began with a delayed 24hr retention test of 10 no KR trials and another acquisition session. One week later, participants performed 10 no KR retention trials 10 transfer trials, in which participants reproduced a slightly different waveform under a goal movement-time of 1150ms. Root mean square error (RMSE), temporal accuracy and spatial accuracy were collected as dependent variables. Acquisition results demonstrated that all video conditions acquired the skill similarly in terms of all dependent variables. Retention results indicated a significant group by time interaction over the 24-hour retention interval (F(2, 42) = 3.809, p = .030), which showed that those in the MM group were significantly better at the 24-hour retention compared to the other groups, however, this mixed-model benefit was no longer seen at the weeklong retention. In conclusion, these results suggest that mixed-model observation is beneficial to motor learning at the 24-hour retention, in terms of temporal accuracy and also that mixed-model observation could potentially lead to enhanced consolidation of a motor skill.

Introduction : La réanimation est une discipline médicale récente ayant pour spécificité une surveillance rapprochée et tracée des patients et de leurs traitements. Une grande quantité de données concernant les caractéristiques des patients, leur prise en charge et leur évolution sont ainsi générées et collectées quotidiennement. La médecine basée sur les preuves oppose classiquement les études observationnelles et interventionnelles et confère à ces dernières, notamment aux études randomisées et contrôlées, un niveau de preuve scientifique supérieur.Objectifs : Décrire l’apport de l’utilisation des données observationnelles en réanimation au travers de travaux récents recourant à différentes méthodologies d’analyse. Discuter les contributions respectives qu’ont les études observationnelles et interventionnelles dans l’acquisition des connaissances scientifiques en réanimation.Méthode : Quatre études observationnelles prospectives multicentriques conduites en réanimation et publiées dans des revues à comité de relecture. Détail de la variété des outils disponibles dans la conception d’études observationnelles à travers différentes méthodes telles que l’utilisation de données en temps réel, la description de cohortes, et l’appariement sur un score de propension afin d’estimer l’effet d’un traitement. Résultats : Les différents travaux détaillés dans cette thèse décrivent la variété des apports des données observationnelles en réanimation. Ces données peuvent constituer un outil de surveillance des épidémies en temps réel comme nous l’avons montré au cours de la pandémie de grippe A H1N1 en France. Elles sont aussi indispensables à la réalisation d’études épidémiologiques telle celle que nous présentons concernant le syndrome de détresse respiratoire aigu. Nous montrons aussi comment ce type de données a remis en question la définition des groupes de sevrage de la ventilation mécanique initialement proposée par une conférence de consensus. Enfin, l’utilisation de techniques statistiques innovantes telles celles basées sur un score de propension a permis l’évaluation du bénéfice de l’utilisation de la circulation extra-corporelle à visée d’oxygénation dans les cas les plus sévères de détresse respiratoire secondaire à la grippe A H1N1.Conclusion : Les études observationnelles ne sont pas à opposer aux études interventionnelles mais apportent des résultats complémentaires et offrent des solutions alternatives lorsqu’une intervention ne peut pas être testée. Connaitre les avantages et limites de chacune des méthodes permet d’optimiser la conception des études l’interprétation des résultats. L’utilisation des données observationnelles en réanimation participe pleinement au progrès des connaissances de cette spécialité. / Introduction: Intensive care is a recent medical specialty which has the particularity to provide a close monitoring and traceability of patients and their treatments. Thus, a huge amount of data is daily collected on characteristics, management and evolution of patients. Evidence based medicine usually confronts observational and interventional studies confers to the latters, particularly randomized controlled trials, a higher scientific quality.Objective: To describe the benefit of observational data for intensive care through recent works using different analysis methods. To discuss respective benefits of observational and interventional studies for scientific knowledge in intensive care.Methods: Four prospective observational multicenter studies conducted in intensive care units and published in peer reviewed journals. Detail of the spectrum of available tools to design observational studies presenting different methods such as real time data use, cohort description and propensity matched analysis to estimate a treatment effect. Results: The studies presented in this thesis describe the different contributions of observational data for intensive care. As we demonstrated during the Influenza A H1N1 pandemics, observational data can be used for a real-time monitoring of epidemics. They are necessary to conduct epidemiological studies such as the acute respiratory distress syndrome study presented. We also show how observational data lead to question the definition of weaning from mechanical ventilation groups initially proposed by a consensus conference. Finally, innovative statistics techniques as propensity score allowed the evaluation of extracorporeal membrane oxygenation for the most severe cases of respiratory failure due the Influenza A H1N1. Conclusion: Observational studies should not be opposed to interventional studies as they provide additional results and give alternative options when an interventional cannot be tested. One must know the benefits and limits of each methods in order to optimize studies design and results interpretation. Observational data are fully part of the knowledge progress of intensive care specialty.

This study evaluates the efficacy of using Equivalence Based Instruction (EBI) to teach historical figures to teenagers with autism in a group setting. Stimuli consisted of three eight-member classes of (A) vocal names of inventors, (B) pictures of inventors, and (C) textual names of their inventions. Participants were assigned their own directly trained class members (Participant 1- A₁₂₃₄, B₁₂₃₄ ,C₁₂₃₄) and (Participant 2 - A₅₆₇₈, B₅₆₇₈, C₅₆₇₈). Participants trained on relation A→B, then after mastery, trained on relation B→C. Probes were conducted followed both A→B and B→C training to assess mastery. Participants each received instructions for three trials then alternated as observer for three trials. Results found both participants demonstrated class formation on their trained stimuli, and one participant demonstrated class formation for his train and observed stimuli. This suggest observational learning with EBI was effective for teaching new academic skills to teenagers with autism.

Indiana University-Purdue University Indianapolis (IUPUI) / Observational studies offer unique advantages over randomized clinical trials (RCTs) in many situations where RCTs are not feasible or suffer from major limitations such as insufficient sample sizes and narrowly focused populations. Because observational data are relatively easy and inexpensive to access, and contain rich and comprehensive demographic and medical information on large and representative populations, they have played a major role in the assessment of the effectiveness and safety of medical interventions. However, observational data also have the challenges of higher rates of missing data and the confounding effect. My proposal is on the development of three statistical methods to address these challenges. The first method is on the refinement and extension of a multiply robust (MR) estimation procedure that simultaneously accounts for the confounding effect and missing covariate process, where we derived the asymptotic variance estimator and extended the method to the scenario where the missing covariate is continuous. The second method focuses on the improvement of estimation precision in an RCT by a historical control cohort. This was achieved through augmenting the conventional effect estimator with an extra mean zero (approximately) term correlated with the conventional effect estimator. In the third method, we calibrated the hidden database bias of an electronic medical records database and utilized an empirical Bayes method to improve the accuracy of the estimation of the risk of acute myocardial infarction associated with a drug by borrowing information from other drugs.

Single subject studies analyze individual behavior identifying how interventions change behavior. Critical to this analysis are repeated baseline measures to identify behavior function and evaluate intervention effects. 40 studies treating child behavior problems between 1997 and 2015 were analyzed. Average student age was 8 years. Most studies used simple frequency counts (47%) of behavior. Baseline observation averaged 42 minutes and 7.4 observations. Most studies (81%) reported no systematic analysis of baseline stability, making it difficult to establish evidence-based effective interventions

Observational learning (OL) allows an individual to acquire novel responses by observing others' behavior and the corresponding consequences. The complexity of skills involved with OL may vary with the learning context. A learner may observe modeled responses to both trained (known) and untrained (unknown) stimuli or they may observe both reinforced (correct) and nonreinforced (incorrect) responses. The purpose of this study was to develop assessment and training procedures for OL component skills when the learner observes a combination of learning contexts: reinforced and nonreinforced responses to both trained and untrained stimuli. Two children with autism, Tom and David, participated. We assessed the following component skills in the context of tact trials: (1) Discriminating trained and untrained stimuli, (2) attending to the modeled performance, (3) discriminating consequences, and (4) conditionally responding based upon a name call. Next, we trained the component skill(s) for which the learner's performance did not meet criterion and then reassessed for OL. For both participants, immediate increases in OL were observed; however, modifications to the post-assessment (differential observing response for consequences and/or differential reinforcement) were required to produce (Tom) or maintain (David) criterion levels of responding. Interpretations of these outcomes, as well as limitations and directions for future research, are discussed.

I have developed a technique to solve for the khronon field in a space-time containing a slowly moving black hole in the khrono-metric regime of Hořava Gravity. To develop these solutions I first revisited the khronon field around static spherically symmetric black holes and perturbed them by a small velocity. The equations of motions of the perturbed field were identified along with the linearly dependent series expansions at the boundary points. Using the boundary conditions and equations of motion the khronon field was numerically solved throughout the space-time. These solutions were used to calculate a sensitivity parameter which defines how the black hole mass appears to be modified due to its velocity. It was found that the sensitivity parameters are highly suppressed and black holes should appear similar to their general relativity counterpart. / Thesis / Master of Science (MSc) / I have investigated slowly moving black holes in a theory of modified gravity. The goal was to see whether the theory breaks down in modelling these black holes and if not, is it possible to test the theory using these predictions. I ultimately found that this theory can model the slowly moving black holes and would appear almost indistinguishable from classically moving black holes. This means that slowly moving black holes on their own will not provide a sufficient test of the theory.

Quasar outflows are a major candidate for Active Galactic Nuclei (AGN) feedback, and their capacity to influence the evolution of their host galaxy depends on the mass-flow rate (M) and kinetic luminosity (E) of the outflowing material. Both quantities require measurement of the distance (R) to the outflow from the central source as well as physical conditions of the outflow, which can be determined using spectral observations of the quasar. This thesis presents spectral analyses leading to measurements of R, M and E for three different quasar outflows. Analysis of LBQS J1206+1052 revealed multiple diagnostic spectral features that could each be used to independently determine R. These diagnostics yielded measurements that were in close agreement, resulting in a robust outflow distance of 840 pc from the central source. This measurement is much larger than predicted from radiative acceleration models (~0.01-0.1 pc), suggesting that outflows appear much farther from the central source than is generally assumed. The outflow in SDSS J0831+0354 was found to carry a kinetic luminosity of 10^45.7 erg/s, which corresponds to 5.2 per cent of the Eddington luminosity of the quasar. This outflow is one of the most energetic outflows to date and satisfies the criteria required to produce AGN feedback effects. A variability study of NGC 5548 revealed an obscuring cloud of gas that shielded the outflow components, dramatically lowering their ionization state. This resulted in the appearance of absorption from the rare element Phosphorus, as well as from sparsely-populated energy levels of CIII and SiIII. These spectral features allowed for an accurate determination of R and for constraints on the ionization phase to be obtained. The latter constraints were used to develop a self-consistent model that explained the variability of all six outflow components during five observing epochs spanning 16 years. / Ph. D.

This thesis contributes to theorising observational drawing from a cognitive perspective. Our current understanding of drawing is developing rapidly through artistic and scientific enquiry. However, it remains fragmented because the frames of reference of those modes of enquiry do not coincide. Therefore, the foundations for a truly interdisciplinary understanding of observational drawing are still inceptive. This thesis seeks to add to those foundations by bridging artistic and scientific perspectives on observational process and the cognitive aptitudes underpinning it. The project is based on four case studies of experienced artists drawing processes, with quantitative and qualitative data gathered: timing of eye and hand movements, and artists verbal reports. The data sets are analysed with a generative approach, using behavioural and protocol analysis methods to yield comparative models that describe cognitive strategies for drawing. This forms a grounded framework that elucidates the cognitive activities and competences observational process entails. Cognitive psychological theory is consulted to explain the observed behaviours, and the combined evidence is applied to understanding apparent discrepancies in existing accounts of drawing. In addition, the use of verbal reporting methods in drawing studies is evaluated. The study observes how drawing process involves a segregation of activities that enables efficient use of limited and parametrically constrained cognitive resources. Differing drawing strategies are shown to share common key characteristics; including a staged use of selective visual attention, and the capacity to temporarily postpone critical judgement in order to engage fully in periods of direct perception and action. The autonomy and regularity of those activities, demonstrated by the artists studied, indicate that drawing ability entails tacit self-knowledge concerning the cognitive and perceptual capacities described in this thesis. This thesis presents drawing as a skill that involves strategic use of visual deconstruction, comparison, analogical transfer and repetitive cycles of construction, evaluation and revision. I argue that drawing skill acquisition and transfer can be facilitated by the elucidation of these processes. As such, this framework for describing and understanding drawing is offered to those who seek to understand, learn or teach observational practice, and to those who are taking a renewed interest in drawing as a tool for thought.