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

The nonfiction collection of essays is about childhood and nostalgia, and how all the experiences as a kid make them into whom they will be.

The purpose of this paper is to analyse which navigational rights are applicable to foreign commercial vessels performing trans-arctic shipping through the Northwest Passage and how this affects the potential for Canada, through article 234 of the United Nations Convention on the Law of the Sea (UNCLOS), to issue national environmental legislation regulating pollution from ships. This is done through the method of legal dogmatics, characterised by analysis of the sources of law and the hierarchy between them. In this paper, the main sources of law employed are UNCLOS and relevant case law from the International Court of Justice. The main conclusions presented in the paper are that the Northwest Passage consists of a combination of territorial sea and exclusive economic zone, which generally means that commercial vessels are allowed innocent passage through the parts of the passage forming the territorial sea and are largely subject to freedom of navigation through those parts that form the exclusive economic zone. However, it seems likely that the Northwest Passage is a strait used for international navigation, in which case, the vessels passing through it are instead subject to the regime of transit passage. This would negatively affect the possibility for Canada to issue national legislation to regulate pollution from foreign vessels. However, as long as the Northwest Passage is covered by ice for most of the year, article 234 UNCLOS allows Canada far more leeway in regard to issuing anti-pollution legislation, both in the territorial sea and the exclusive economic zone, regardless of whether the Northwest Passage is found to be a strait used for international navigation. The passage regime applicable to foreign commercial vessels under article 234 could be characterised as a sui generis passage.

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, December 2014. / Industrial units cannot operate without failure forever. When the operation of a unit deviates from industrial standards, it is considered to have failed. The time from the moment a unit enters service until it fails is its lifetime. Within reliability and often in life data analysis in general, lifetime is the event of interest. For highly reliable units, accelerated life testing is required to obtain lifetime data quickly. Accelerated tests where failure is not instantaneous, but the end point of an underlying degradation process are considered. Failure during testing occurs when the performance of the unit falls to some specified threshold value such that the unit fails to meet industrial specifications though it has some residual functionality (degraded failure) or decreases to a critical failure level so that the unit cannot perform its function to any degree (critical failure). This problem formulation satisfies the random signs property, a notable competing risks formulation originally developed in maintenance studies but extended to accelerated testing here. Since degraded and critical failures are linked through the degradation process, the open problem of modelling dependent competing risks is discussed. A copula model is assumed and expert opinion is used to estimate the copula. Observed occurrences of degraded and critical failure times are interpreted as times when the degradation process first crosses failure thresholds and are therefore postulated to be distributed as inverse Gaussian. Based on the estimated copula, a use-level unit lifetime distribution is extrapolated from test data. Reliability metrics from the extrapolated use-level unit lifetime distribution are found to differ slightly with respect to different degrees of stochastic dependence between the risks. Consequently, a degree of dependence between the risks that is believed to be realistic to admit is considered an important factor when estimating the use-level unit lifetime distribution from test data. Keywords: Lifetime; Accelerated testing; Competing risks; Copula; First passage time.

Une multitude d'algorithmes d'exclusion mutuelle ont été conçus au cours des vingt cinq dernières années, dans le but d'améliorer les performances liées à l'exécution de sections critiques et aux verrous.Malheureusement, il n'existe actuellement pas d'étude générale et complète au sujet du comportement de ces algorithmes d'exclusion mutuelle sur des applications réalistes (par opposition à des applications synthétiques) qui considère plusieurs métriques de performances, telles que l'efficacité énergétique ou la latence.Dans cette thèse, nous effectuons une analyse pragmatique des mécanismes d'exclusion mutuelle, dans le but de proposer aux développeurs logiciels assez d'informations pour leur permettre de concevoir et/ou d'utiliser des mécanismes rapides, qui passent à l'échelle et efficaces énergétiquement.Premièrement, nous effectuons une étude de performances de 28 algorithmes d'exclusion mutuelle faisant partie de l'état de l'art, en considérant 40 applications et quatre machines multicœurs différentes.Nous considérons non seulement le débit (la métrique de performance traditionnellement considérée), mais aussi l'efficacité énergétique et la latence, deux facteurs qui deviennent de plus en plus importants.Deuxièmement, nous présentons une analyse en profondeur de nos résultats.Plus particulièrement, nous décrivons neufs problèmes de performance liés aux verrous et proposons six recommandations aidant les développeurs logiciels dans le choix d'un algorithme d'exclusion mutuelle, se basant sur les caractéristiques de leur application ainsi que les propriétés des différents algorithmes.A partir de notre analyse détaillée, nous faisons plusieurs observations relatives à l'interaction des verrous et des applications, dont plusieurs d'entre elles sont à notre connaissance originales:(i) les applications sollicitent fortement les primitives lock/unlock mais aussi l'ensemble des primitives de synchronisation liées à l'exclusion mutuelle (ex. trylocks, variables de conditions),(ii) l'empreinte mémoire d'un verrou peut directement impacter les performances de l'application,(iii) pour beaucoup d'applications, l'interaction entre les verrous et l'ordonnanceur du système d'exploitation est un facteur primordial de performance,(iv) la latence d'acquisition d'un verrou a un impact très variable sur la latence d'une application,(v) aucun verrou n'est systématiquement le meilleur,(vi) choisir le meilleur verrou est difficile, et(vii) l'efficacité énergétique et le débit vont de pair dans le contexte des algorithmes d'exclusion mutuelle.Ces découvertes mettent en avant le fait que la synchronisation à base de verrou ne se résume pas seulement à la simple interface "lock - unlock".En conséquence, ces résultats appellent à plus de recherche dans le but de concevoir des algorithmes d'exclusion mutuelle avec une empreinte mémoire faible, adaptatifs et qui implémentent l'ensemble des primitives de synchronisation liées à l'exclusion mutuelle.De plus, ces algorithmes ne doivent pas seulement avoir de bonnes performances d'un point de vue du débit, mais aussi considérer la latence ainsi que l'efficacité énergétique. / A plethora of optimized mutual exclusion lock algorithms have been designed over the past 25 years to mitigate performance bottlenecks related to critical sections and synchronization.Unfortunately, there is currently no broad study of the behavior of these optimized lock algorithms on realistic applications that consider different performance metrics, such as energy efficiency and tail latency.In this thesis, we perform a thorough and practical analysis, with the goal of providing software developers with enough information to achieve fast, scalable and energy-efficient synchronization in their systems.First, we provide a performance study of 28 state-of-the-art mutex lock algorithms, on 40 applications, and four different multicore machines.We not only consider throughput (traditionally the main performance metric), but also energy efficiency and tail latency, which are becoming increasingly important.Second, we present an in-depth analysis in which we summarize our findings for all the studied applications.In particular, we describe nine different lock-related performance bottlenecks, and propose six guidelines helping software developers with their choice of a lock algorithm according to the different lock properties and the application characteristics.From our detailed analysis, we make a number of observations regarding locking algorithms and application behaviors, several of which have not been previously discovered:(i) applications not only stress the lock/unlock interface, but also the full locking API (e.g., trylocks, condition variables),(ii) the memory footprint of a lock can directly affect the application performance,(iii) for many applications, the interaction between locks and scheduling is an important application performance factor,(iv) lock tail latencies may or may not affect application tail latency,(v) no single lock is systematically the best,(vi) choosing the best lock is difficult (as it depends on many factors such as the workload and the machine), and(vii) energy efficiency and throughput go hand in hand in the context of lock algorithms.These findings highlight that locking involves more considerations than the simple "lock - unlock" interface and call for further research on designing low-memory footprint adaptive locks that fully and efficiently support the full lock interface, and consider all performance metrics.

Nous étudions dans cette thèse le problème de reconstruction 3D multi-vue à partir d’une séquence d’images au sol acquises dans des environnements urbains ainsi que la prise en compte d’a priori permettant la préservation de la structure sous-jacente de la géométrie 3D observée, ainsi que le passage à l’échelle de tels processus de reconstruction qui est intrinsèquement délicat dans le contexte de l’imagerie urbaine. Bien que ces deux axes aient été traités de manière extensive dans la littérature, les méthodes de reconstruction 3D structurée souffrent d’une complexité en temps de calculs restreignant significativement leur intérêt. D’autre part, les approches de reconstruction 3D large échelle produisent généralement une géométrie simplifiée, perdant ainsi des éléments de structures qui sont importants dans le contexte urbain. L’objectif de cette thèse est de concilier les avantages des approches de reconstruction 3D structurée à celles des méthodes rapides produisant une géométrie simplifiée. Pour ce faire, nous présentons “Patchwork Stereo”, un framework qui combine stéréoscopie photométrique utilisant une poignée d’images issues de points de vue éloignés, et un nuage de point épars. Notre méthode intègre une analyse simultanée 2D-3D réalisant une extraction robuste de plans 3D ainsi qu’une segmentation d’images top-down structurée et repose sur une optimisation par champs de Markov aléatoires. Les contributions présentées sont évaluées via des expériences quantitatives et qualitatives sur des données d’imagerie urbaine complexes illustrant des performances tant quant à la fidélité structurelle des reconstructions 3D que du passage à l’échelle / In this thesis, we address the problem of 3D reconstruction from a sequence of calibrated street-level photographs with a simultaneous focus on scalability and the use of structure priors in Multi-View Stereo (MVS).While both aspects have been studied broadly, existing scalable MVS approaches do not handle well the ubiquitous structural regularities, yet simple, of man-made environments. On the other hand, structure-aware 3D reconstruction methods are slow and scale poorly with the size of the input sequences and/or may even require additional restrictive information. The goal of this thesis is to reconcile scalability and structure awareness within common MVS grounds using soft, generic priors which encourage : (i) piecewise planarity, (ii) alignment of objects boundaries with image gradients and (iii) with vanishing directions (VDs), and (iv) objects co-planarity. To do so, we present the novel “Patchwork Stereo” framework which integrates photometric stereo from a handful of wide-baseline views and a sparse 3D point cloud combining robust 3D plane extraction and top-down image partitioning from a unified 2D-3D analysis in a principled Markov Random Field energy minimization. We evaluate our contributions quantitatively and qualitatively on challenging urban datasets and illustrate results which are at least on par with state-of-the-art methods in terms of geometric structure, but achieved in several orders of magnitude faster paving the way for photo-realistic city-scale modeling

Considerando a importância dos rituais no processo de reconhecimento social mútuo entre os seres humanos e, consequentemente, no desenvolvimento dos adolescentes, este trabalho tem por objetivos: identificar, numa comunidade estudantil de uma escola de educação profissional, os impactos causados no processo de formação dos jovens, pelo declínio dos ritos de passagem e identificar, no imaginário desse grupo de alunos, os universos míticos que o compõem. Para isso, parte-se do pressuposto de que os rituais, sejam eles sagrados ou profanos, expressam as regras e os valores que orientam o comportamento dos seres humanos em grupo e em sociedade e que o declínio dos ritos iniciáticos, sobretudo na adolescência, faz dos jovens suas principais vítimas. Os eixos teóricos organizadores foram a Teoria do Imaginário de Gilbert Durand e a Sócioantropologia do Cotidiano de Michel Maffesoli. Como metodologias foram utilizados: questionários para a identificação da situação socioeconômica e cultural do grupo, observação para a identificação de ritos e mitos no contexto escolar, entrevistas com alunos, professores, coordenadores e outros funcionários e o Teste Arquetípico de Nove Elementos AT-9, elaborado por Yves Durand, para identificar os universos míticos do grupo de alunos e como esses se relacionam com o mundo. / Considering the importance of rituals in the process of mutual social recognition between human beings and in consequence, the development of adolescents, this study aims to identify, in a student community of a school of professional education, the impacts on the formation process young people, caused of the decline of rites of passage and identify in the imaginarys group, mythical universes that compose it. For this, we start from the assumption that rituals, whether sacred or profane, express the rules and values that guide the behavior of human beings in groups and in society and the decline of initiation rites, especially in adolescence, making of the youths its mayor victims. The theoretical axes organizers were the Theory of Imaginary Gilbert Durand and Social Anthropology of Quotidian by Michel Maffesoli. The methodology we used questionnaires to identify the socioeconomic and cultural group, observation to identify rites and myths in the school context, interviews with students, teachers, coordinator and other employees and Archetypal Test Nine Elements - AT-9, produced by Yves Durand, to identify the mythical universes group of students and how these relate to the world.

The effect of increased neutral detergent fibre digestibility (NDFD) of sugarcane silage on intake, rumen kinetics and metabolism, microbial population, performance, and body fatness of beef cattle was evaluated through two trials. In the metabolism trial, eight ruminal-cannulated Nellore steers were used in a replicated 4×4 Latin square design. In the performance trial, forty-eight Nellore young bulls were used in a complete randomized block design with a 2×2 factorial arrangement of treatments. Two sugarcane genotypes with high or low NDFD harvested for silage in two maturity stages were used (2 genotypes and 2 maturity stages). Diets were formulated with 40% of sugarcane on dry matter (DM) basis. Intake of DM was likely limited by metabolic feedback. The DM intake (DMI) of cannulated steers was reduced when late-maturity sugarcane was fed, but only with low-NDFD genotype. Turnover and passage rate of NDF was accelerated when high-NDFD genotype was fed. Rumen DM, NDF and iNDF pools were greater when diets with the low-NDFD genotype were fed. There was a tendency for greater relative populations of F. succinogenes and R. albus when animals were fed with diets containing low-NDFD genotype. Performance and carcass characteristics were not affected by treatments. Excess of NFC and fermentation end products of sugarcane silage can limit intake by metabolic pathway. High-NDFD genotype can accelerated NDF turnover and passage rate in the rumen. Late-maturity ensiled sugarcane can reduce DMI of beef steers fed with low-NDFD genotype. The effect of live yeast (LY - Saccharomyces cerevisiae CNCM I-1077) on in situ fiber digestibility, rumen fermentation, and rumen cellulolytic bacteria population of grazing Nellore cattle was evaluated throughout the year. Eight rumen cannulated steers were used in a 2x4 factorial arrangement of treatments: with or without LY, and the four seasons of the year. Yeast was given daily to provide 8x109 CFU per animal. Animals were kept on a rotational grazing system with mineral supplementation. Every 45 d, in situ rumen NDF degradability of 5 reference forages was determined after 24 and 48h incubation. Rumen fluid was collected to measure yeast count and fermentation parameters, and rumen contents collected for quantitative PCR quantification of cellulolytic bacteria. Although pasture composition varied greatly throughout the year, there was no LY*season interaction. Yeast supplementation increased NDF degradability in all seasons. Among the four rumen bacteria evaluated, R. flavefaciens was the most prevalent and LY increased R. flavefaciens population in the summer and spring. Supplementing LY can benefit fibre-degrading bacteria and increase fibre degradability of grazing animals, independently of the season. / O efeito do aumento da digestibilidade da fibra detergente neutro (DFDN) da silagem de cana-de-açúcar sobre consumo, cinética e metabolismo ruminal, população microbiana, desempenho e características de carcaça de bovinos de corte foram avaliados através de dois experimentos. No experimento de metabolismo, oito novilhos Nelore canulados no rúmen foram utilizados em delineamento experimental com dois quadrados latinos 4×4 contemporâneos. No experimento de desempenho, quarenta e oito novilhos nelore foram usados em delineamento em blocos inteiramente casualizados com arranjo de tratamento em fatorial 2×2. Dois genótipos de cana-de-açúcar com alta e baixa-DFDN colhidos para ensilagem em dois estágios de maturidade (2 genótipos e 2 estágios de maturidade). As dietas foram formuladas contendo 40% de silagem de cana-de-açúcar na matéria seca. O consumo de matéria seca (CMS) foi limitado pela via metabólica. O CMS dos novilhos canulados no rúmen foi reduzido quando foram alimentados com a cana-de-açúcar colhida na maturidade tardia, mas somente para o genótipo de baixa-DFDN. A taxa de passagem e o turnover de FDN foram acelerados quando o genótipo de alta-DFDN foi fornecido. O pool ruminal de MS, FDN e FDNi foram maiores para as dietas contendo o genótipo de baixa-DFDN. Houve tendência para maior população relativa de F. succinogenes e R. albus quando os animais foram alimentado com dietas contendo o genótipo de baixa-DFDN. O desempenho e as características de carcaça não foram afetados pelos tratamentos. O excesso de carboidratos não fibrosos (CNF) e os produtos de fermentação das silagens podem limitar o consumo pela via metabólica. O genótipo de alta-DFDN pode acelerar a taxa de passagem e o turnover de FDN no rúmen. O CMS pode ser reduzido quando o genótipo de baixa-DFDN é colhido para ensilagem com maturidade tardia. O feito da suplementação com levedura viva (LV - Saccharomyces cerevisiae CNCM I-1077) sobre a digestibilidade in situ, fermentação ruminal e população de bactérias celulolíticas no rúmen de bovinos Nelore em pastejo foi avaliado ao longo de um ano. Oito novilhos canulados no rúmen foram usados em arranjo fatorial 2×4: com ou sem LV e quantro estações do ano. O tratamento com LV foi realizado diariamente para promover uma suplementação de 8x109 UFC por animal. Os animais foram mantidos em sistema de pastejo rotativo com suplementação mineral. A cada 45 dias, foi realizada a degradação de FDN n situ de 5 forragens referencia, determinada após 24 e 48h de incubação ruminal. O fluido ruminal foi coletado para avaliar a contagem de leveduras e os parâmetros de fermentação, e ainda para a quantificação de bactérias celulolíticas por PCR. Mesmo com grande variação da qualidade do pasto ao longo do ano, não foi observado interação entre LV*estação do ano. A suplementação com LV aumentou a degradabilidade da FDN em todas as estações do ano. Entre as quatro bactérias ruminais avaliadas, a R. flavefaciens foi a mais prevalente e o tratamento com LV aumentou sua população relativa no verão e na primavera. A suplementação com LV pode beneficiar bactérias degradadoras de FDN e aumentar a digestibilidade ruminal de fibra em animais em pastejo, independentemente da estação do ano.

Células cultivadas por longos períodos acumulam alterações genéticas e epigenéticas que resultam frequentemente em uma inapropriada reprogramação nuclear de embriões submetidos à transferência nuclear a partir de células somáticas (TNCS). Além disso, a variável sexo é um fator limitante na produção de blastocistos e na competência de desenvolvimento pós-implantação de embriões produzidos in vitro. Desta maneira, o objetivo deste trabalho foi estudar o efeito do número da passagem nos experimentos de transferência nuclear, bem como, avaliar o efeito do sexo no desenvolvimento in vitro e no potencial pós-implantação destes embriões. Para tanto, oócitos derivados de matadouro foram enucleados e reconstruídos com células somáticas de animal adulto a partir de 18 horas pós-maturação. Após a fusão (dois pulsos de 2,25 kv/cm durante 65 µseg) e ativação química (ionomicina - 5,0 µM durante 5 minutos e 6-DMAP - 2,0 mM durante 3 horas), os zigotos reconstituídos com núcleo de célula somática foram cultivados em CR2 com monocamada de células da granulosa a 38,8ºC, em atmosfera umidificada e 5% de CO2 em ar durante 7 dias. Os resultados foram analisados utilizando o teste Qui-quadrado (X2). No cultivo in vitro, embriões reconstruídos com células em passagens tardias apresentaram menores taxas de clivagem, 8 células e desenvolvimento a blastocisto (p < 0,05). Embriões reconstruídos com células em passagens iniciais apresentaram maior competência em formar um blastocisto (16% versus 14% - intermediárias e 7% - tardias; p < 0,05). Apesar dos embriões reconstruídos com células em passagens tardias apresentarem resultados semelhantes de prenhez aos 30 dias (35% versus 27% - iniciais e 26% - intermediárias), não foram competentes para o desenvolvimento de uma gestação a termo (0% versus 34% - iniciais e 25% - intermediárias). Além de não apresentarem diferenças nas taxas de desenvolvimento a termo, neonatos produzidos com células em passagens iniciais e intermediárias apresentaram taxas equivalentes de sobrevivência (50% vs 57%, respectivamente). Em relação ao sexo, embora maior taxa de clivagem tenha sido observada para fêmeas (78% vs 74%; p < 0,05), embriões machos foram mais competentes no desenvolvimento a blastocisto (16% vs 14,5%; p < 0,05). As taxas de prenhez, desenvolvimento a termo e sobrevivência foram semelhantes entre os gêneros. Entretanto, fêmeas apresentaram maior taxa de aborto entre 90 e 120 dias de gestação (p < 0,05). Em conclusão, estes resultados indicam que células doadoras de núcleos cultivados por um longo período dificultam a produção de blastocistos e aumentam as chances de perdas durante a gestação. Também foi possível concluir que embriões clonados do gênero masculino apresentam maior competência para desenvolver a blastocisto e suportar uma gestação a temo. / Cells cultured for long-term periods accumulate genetic and epigenetic modifications that result in improper nuclear reprogramming of somatic cell nuclear transfer (SCNT) embryos. Furthermore, the sex may be a limiting factor in blastocysts production and in post-implantation developmental competence. Therefore, the objective of this study was to determine the effect of the passage number for SCNT, and to evaluate the effect of sex on in vitro development and on post-implantational competence of these embryos. Oocytes obtained from slaughtered cows were enucleated and reconstructed by TNCS from an adult animal at 18 hours of in vitro maturation. After fusion (two 2.25 kv/cm DC pulses for 65 µsec) and chemical activation (5.0 µM ionomycin for 5 min followed by 2.0 mM 6-DMAP for 3 hours), the reconstructed zygotes were cultured in CR2 on a granulosa cell monolayer at 38.8ºC in a humidified atmosphere of 5% CO2 in air for 7 days. Data were analyzed using Chi Square analysis. Reconstructed embryos with cells on late passages showed lower rates for cleavage, 8 cells embryos and blastocyst formation (p < 0.05). Reconstructed embryos with cells on early passages showed higher competence to blastocyst formation (16% versus 14% - intermediate and 7% - late; p < 0.05). Although reconstructed embryos with cells on late passages showed similar results for pregnancy on day 30 (35% versus 27% - early and 26% - intermediate), they were not competent to develop to term. Calving rates and perinatal survival (PNS) were similar when comparing early and intermediate passages (34% vs 25% and 50% vs 57%, respectively). Regarding sex, although cleavage rates were higher for female embryos (78% vs 74%; p < 0.05), male embryos were more competent for blastocyst formation (16% vs 14.5%; p < 0.05). The pregnancy rate, development to term and PNS were similar between gender, however, female embryos showed higher rates of abortion between day 90 and 120. In conclusion, these results indicate that long-term culture of donor cells decrease blastocyst formation and increase the chances of failure during pregnancy. Futhermore, cloned male embryos were more competent to form a blastocyst and had lower rates of abortion.

No presente trabalho provamos resultados sobre as flutuações dos fluxos de partículas e das partículas marcadas no processo de Hammersley multiclasse. Os métodos das demonstrações são robustos, formulados de modo a serem aplicados em outros processos, em particular se aplicam ao processo de exclusão totalmente assimétrico multiclasse (TASEP multiclasse) e à seu respectivo modelo de percolação de última passagem. Os principais teoremas obtidos são um teorema central do limite para o choque, seu coeficiente de difusão e uma fórmula exata para a variância do fluxo de partículas de classe N >1 para o processo em equilíbrio multiclasse. / We prove fluctuations results concerning fluxes of particles and tagged particles on multiclass Hammersley process. The methods used are robust and apply to other processes, in particular all the proofs can be adapted to the Multiclass totally asymmetric simple exclusion process (Multiclass TASEP) and its respective last passage percolation model. The main theorems obtained are a central limit theorem for the shock, its diffusion coefficient and an exact formula for the variance of the $N$-th class particle flux in a stationary version of the multiclass process when N > 1.