Epigenetic reprogramming of imprinted genes in embryonic stem cells, fertilized and cloned embryos

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Facteurs psychosociaux liés aux risques d'infections virales (VIH/sida et hépatites) chez les cocaïnomanes

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Physiologically based pharmacokinetic modelling in drug delivery

The application of pharmacokinetic modelling within the drug development field essentially allows one to develop a quantitative description of the temporal behaviour of a compound of interest at a tissue/organ level, by identifying and defining relationships between a dose of a drug and dependent variables. In order to understand and characterise the pharmacokinetics of a drug, it is often helpful to employ pharmacokinetic modelling using empirical or mechanistic approaches. Pharmacokinetic models can be developed within mathematical and statistical commercial software such as MATLAB using traditional mathematical and computation coding, or by using the Simbiology Toolbox available within MATLAB for a graphical user interface approach to developing pharmacokinetic (PBPK) models. For formulations dosed orally, a prerequisite for clinical activity is the entry of the drug into the systemic circulation.

Epigenetic reprogramming of imprinted genes in embryonic stem cells, fertilized and cloned embryos

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Facteurs psychosociaux liés aux risques d'infections virales (VIH/sida et hépatites) chez les cocaïnomanes

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Modern foreign languages get a voice: the role of the journals

This chapter investigates the significance of specialized journals for the development of modern language teaching. It begins by explaining the development of language journals up to the point at which language teaching reform really took off with the emergence of the so-called Reform Movement in the 1880s. The principal journal for this movement was Phonetische studien [Phonetic Studies] founded in 1888 and renamed Die neueren Sprachen [Modern languages] in 1894. The style of the early issues of this journal allows modern readers an insight into the discourse practices of that community of language scholars and teachers, the opportunity to hear its characteristic ‘voice’ and recreate the means by which modern foreign language teaching became an independent discipline.

STPA-SafeSec: Safety and Security Analysis for Cyber-Physical Systems

Cyber-physical systems tightly integrate physical processes and information and communication technologies. As today’s critical infrastructures, e.g., the power grid or water distribution networks, are complex cyber-physical systems, ensuring their safety and security becomes of paramount importance. Traditional safety analysis methods, such as HAZOP, are ill-suited to assess these systems. Furthermore, cybersecurity vulnerabilities are often not considered critical, because their effects on the physical processes are not fully understood. In this work, we present STPA-SafeSec, a novel analysis methodology for both safety and security. Its results show the dependencies between cybersecurity vulnerabilities and system safety. Using this information, the most effective mitigation strategies to ensure safety and security of the system can be readily identified. We apply STPA-SafeSec to a use case in the power grid domain, and highlight its benefits.

DES14X3taz: A Type I Superluminous Supernova Showing a Luminous, Rapidly Cooling Initial Pre-peak Bump

We present DES14X3taz, a new hydrogen-poor superluminous supernova (SLSN-I) discovered by the Dark Energy Survey (DES) supernova program, with additional photometric data provided by the Survey Using DECam for Superluminous Supernovae. Spectra obtained using Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy on the Gran Telescopio CANARIAS show DES14X3taz is an SLSN-I at z = 0.608. Multi-color photometry reveals a double-peaked light curve: a blue and relatively bright initial peak that fades rapidly prior to the slower rise of the main light curve. Our multi-color photometry allows us, for the first time, to show that the initial peak cools from 22,000 to 8000 K over 15 rest-frame days, and is faster and brighter than any published core-collapse supernova, reaching 30% of the bolometric luminosity of the main peak. No physical 56Ni-powered model can fit this initial peak. We show that a shock-cooling model followed by a magnetar driving the second phase of the light curve can adequately explain the entire light curve of DES14X3taz. Models involving the shock-cooling of extended circumstellar material at a distance of 400  are preferred over the cooling of shock-heated surface layers of a stellar envelope. We compare DES14X3taz to the few double-peaked SLSN-I events in the literature. Although the rise times and characteristics of these initial peaks differ, there exists the tantalizing possibility that they can be explained by one physical interpretation.

Towards a Resilience Metric Framework for Cyber-Physical Systems

Resilience is widely accepted as a desirable system property for cyber-physical systems. However, there are no metrics that can be used to measure the resilience of cyber-physical systems (CPS) while the multi-dimensional nature of performance in these systems is considered. In this work, we present first results towards a resilience metric framework. The key contributions of this framework are threefold: First, it allows to evaluate resilience with respect to different performance indicators that are of interest. Second, complexities that are relevant to the performance indicators of interest, can be intentionally abstracted. Third and final, it supports the identification of reasons for good or bad resilience to improve system design.

Comunicación

El primero de septiembre de 1976 se colectaron varias muestras de Equisetum giganteum en el Bajío de Palo Blanco, en la aldea Bolaños, cerca del Cerro y Río Singüil del departamento de Santa Ana no reportada para ese lugar. Fue reportada anteriormente en el pantano de Ateos por el Dr. Salvador Calderón e Ing. Paul C. Stanley en la flora salvadoreña, lista preliminar de plantas de El Salvador, C.A. El lugar donde fue reportada anteriormente ya no existe por lo cual esta especie se creía extinta. Posteriormente se hará un estudio exhaustivo de esta planta.

CAUSAL INFERENCE WITH A CONTINUOUS TREATMENT AND OUTCOME: ALTERNATIVE ESTIMATORS FOR PARAMETRIC DOSE-RESPONSE FUNCTIONS WITH APPLICATIONS.

Causal inference with a continuous treatment is a relatively under-explored problem. In this dissertation, we adopt the potential outcomes framework. Potential outcomes are responses that would be seen for a unit under all possible treatments. In an observational study where the treatment is continuous, the potential outcomes are an uncountably infinite set indexed by treatment dose. We parameterize this unobservable set as a linear combination of a finite number of basis functions whose coefficients vary across units. This leads to new techniques for estimating the population average dose-response function (ADRF). Some techniques require a model for the treatment assignment given covariates, some require a model for predicting the potential outcomes from covariates, and some require both. We develop these techniques using a framework of estimating functions, compare them to existing methods for continuous treatments, and simulate their performance in a population where the ADRF is linear and the models for the treatment and/or outcomes may be misspecified. We also extend the comparisons to a data set of lottery winners in Massachusetts. Next, we describe the methods and functions in the R package causaldrf using data from the National Medical Expenditure Survey (NMES) and Infant Health and Development Program (IHDP) as examples. Additionally, we analyze the National Growth and Health Study (NGHS) data set and deal with the issue of missing data. Lastly, we discuss future research goals and possible extensions.

Connecting: the use of information and communication technologies by older adults in a retirement community

This is a long-term study of the use of information and communication technologies by 30 older adults (ages 70–97) living in a large retirement community. The study spanned the years of 1996 to 2008, during which time the research participants grappled with the challenges of computer use while aging 12 years. The researcher, herself a ‘mature learner,’ used a qualitative research design which included observations and open-ended interviews. Using a strategy of “intermittent immersion,” she spent an average of two weeks per visit on site and participated in the lives of the research population in numerous ways, including service as their computer tutor. With e-mail and telephone contact, she was able to continue her interactions with participants throughout the 12-year period. A long-term perspective afforded the view of the evolution, devolution or cessation of the technology use by these older adults, and this process is chronicled in detail through five individual “profiles.” Three research questions dominated the inquiry: What function do computers serve in the lives of older adults? Does computer use foster or interfere with social ties? Is social support necessary for success in the face of challenging learning tasks? In answer to the first question, it became clear that computers were valued as a symbol of competence and intelligence. Some individuals brought their computers with them when transferred to the single-room residences of assisted living or nursing care facilities. Even when use had ceased, their computers were displayed to signal that their owners were or had once been keeping up to date. In answer to the second question, computer owners socialized around computing use (with in-person family members or friends) more than, or as much as, they socialized through their computers in the digital realm of the Internet. And in answer to the third question, while the existence of social support did facilitate computer exploration, more important was the social support network generated and developed among fellow computer users.

Dynamic instabilities in scalar neural field equations with space-dependent delays

In this paper we consider a class of scalar integral equations with a form of space-dependent delay. These non-local models arise naturally when modelling neural tissue with active axons and passive dendrites. Such systems are known to support a dynamic (oscillatory) Turing instability of the homogeneous steady state. In this paper we develop a weakly nonlinear analysis of the travelling and standing waves that form beyond the point of instability. The appropriate amplitude equations are found to be the coupled mean-field Ginzburg-Landau equations describing a Turing-Hopf bifurcation with modulation group velocity of O(1). Importantly we are able to obtain the coefficients of terms in the amplitude equations in terms of integral transforms of the spatio-temporal kernels defining the neural field equation of interest. Indeed our results cover not only models with axonal or dendritic delays but those which are described by a more general distribution of delayed spatio-temporal interactions. We illustrate the predictive power of this form of analysis with comparison against direct numerical simulations, paying particular attention to the competition between standing and travelling waves and the onset of Benjamin-Feir instabilities.