Entanglement-assisted communication complexity and nonlocal games

Ce mémoire étudie le problème ancestral 1 de déterminer la puissance relative de l’intrication préalable en complexité de la communication comparée à la communication quantique. L’idée maîtresse du mémoire est d’opérer un rapprochement entre la complexité de la communication et la théorie des jeux non-locaux. Spécifiquement, nous contemplons une variété de manières de convertir des jeux non-locaux pour lesquels il est su que beaucoup d’intrication est requise en problèmes de complexité de la communication. Ce faisant, nous obtenons les problèmes de communications affichant les plus grands écarts connus à ce jour entre les deux modèles pour des problèmes fonctionnels.Ce mémoire étudie le problème ancestral 1 de déterminer la puissance relative de l’intrication préalable en complexité de la communication comparée à la communication quantique. L’idée maîtresse du mémoire est d’opérer un rapprochement entre la complexité de la communication et la théorie des jeux non-locaux. Spécifiquement, nous contemplons une variété de manières de convertir des jeux non-locaux pour lesquels il est su que beaucoup d’intrication est requise en problèmes de complexité de la communication. Ce faisant, nous obtenons les problèmes de communications affichant les plus grands écarts connus à ce jour entre les deux modèles pour des problèmes fonctionnels

On the Quantum Chromatic Numbers of Small Graphs

We make two contributions pertaining to the study of the quantum chromatic numbers of small graphs. Firstly, in an elegant paper, Man\v{c}inska and Roberson [\textit{Baltic Journal on Modern Computing}, 4(4), 846-859, 2016] gave an example of a graph $G_{14}$ on 14 vertices with quantum chromatic number 4 and classical chromatic number 5, and conjectured that this is the smallest graph exhibiting a separation between the two parameters. We describe a computer-assisted proof of this conjecture, thereby resolving a longstanding open problem in quantum graph theory. Our second contribution pertains to the study of the rank-$r$ quantum chromatic numbers. While it can now be shown that for every $r$, $\chi_q$ and $\chi^{(r)}_q$ are distinct, few small examples of separations between these parameters are known. We give the smallest known example of such a separation in the form of a graph $G_{21}$ on 21 vertices with $\chi_q(G_{21}) = \chi^{(2)}_q(G_{21}) = 4$ and $\xi(G_{21}) = \chi^{(1)}_q(G_{21}) = \chi(G_{21}) = 5$. The previous record was held by a graph $G_{msg}$ on 57 vertices that was first considered in the aforementioned paper of Man\v{c}inska and Roberson and which satisfies $\chi_q(G_{msg}) = 3$ and $\chi^{(1)}_q(G_{msg}) = 4$. In addition, $G_{21}$ provides the first provable separation between the parameters $\chi^{(1)}_q$ and $\chi^{(2)}_q$. We believe that our techniques for constructing $G_{21}$ and lower bounding its orthogonal rank could be of independent interest

Développement de la végétation saisonnière et dynamique hydrosédimentaire sur les bancs alluviaux

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

La réfutation kantienne des preuves de l'existence de Dieu

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Portée de l'archéoentomologie dans l'étude des maisons hivernales inuites (période de contact à Dog Island, Labrador, 17e et 18e siècles)

Cette recherche consiste en une analyse archéoentomologique portant sur des échantillons prélevés dans trois maisons hivernales inuites d’Oakes Bay 1, dans la région de Nain, au Labrador. L’analyse a deux objectifs : contribuer à la recherche sur la période transitoire critique que traversent les Inuits du Labrador entre le 17e et le 18e siècle, qu’on observe principalement dans un changement structural des maisons hivernales et explorer le potentiel de l’archéoentomologie dans les régions arctiques et subarctiques pour combler les lacunes dans nos interprétations. Une analyse approfondie de l’écologie des insectes indique que les assemblages archéoentomologiques provenant de contextes inuits ne sont pas les plus aptes à étudier les conditions de vie à l’intérieur des maisons. En revanche, ils servent à mieux comprendre l’utilisation de matériaux divers lors de l’occupation hivernale, à discuter du processus de formation du site et à éclairer le processus d’abandon temporaire et permanent de l’habitation hivernale, un aspect critique de l’histoire de l’occupation des sites archéologiques qu’il est difficile d’observer avec les méthodes de terrain conventionnelles.An archaeoentomological analysis was conducted on sediment samples collected from three Inuit winter houses located at Oakes Bay 1, in the Nain region, Labrador. The analysis’ primary goal is to contribute new perspectives to research concerning the reorganization of Labrador Inuit winter houses and winter households during the 17th and 18th centuries, a significant period of transition in their history. Secondly, the project seeks to explore the potential of archaeoentomology to contribute to archaeology in the Arctic and Subarctic regions. Following an in depth analysis of the ecology of insects collected from Oakes Bay 1, we conclude that archaeoentomological assemblages from Inuit contexts are not well suited for the study of domestic living conditions. Instead, archaeoentomological assemblages were more productively employed to document the use of a variety of food and raw materials in the house, to document site formation and to shed light on temporary and permanent abandonment of winter houses, a critical aspect of the occupation history of all archaeological sites that is difficult to observe through conventional archaeological field methods

Influence de la rigidité du revêtement sur les prédictions de soulèvement au gel

Chaque année, lors de la saison hivernale, la pénétration du gel dans les structures de chaussées induit de nouvelles contraintes pouvant provoquer des soulèvements au gel. En fonction de la structure de chaussée, plusieurs outils de prédiction permettent de quantifier la grandeur de ces soulèvements au gel. Par contre, dans ces outils, le type de revêtement n’est pas considéré. Le but de ce projet est de déterminer si la rigidité d’un revêtement de chaussée influence la grandeur des soulèvements au gel. Présentement, lors du dimensionnement d’une structure de chaussée, les soulèvements au gel sont limités sur autoroute par le Ministère des Transports du Québec à 50 mm pour les chaussées à revêtement bitumineux et 40 mm pour les chaussées à revêtement rigide. Lorsque les prévisions de soulèvements au gel dépassent ces valeurs, l’épaisseur de la couche de matériau granulaire est augmentée dans le but de diminuer la portion de sol d’infrastructure gélif exposé au gel. L’installation d’un revêtement de chaussée limitant les soulèvements au gel permettrait de diminuer l’épaisseur de la couche de matériau granulaire, ce qui pourrait entraîner des économies intéressantes. Pour répondre à la problématique, un logiciel d’analyse par différences finies a été utilisé dans le but d’y modéliser une structure de chaussée. Le revêtement de cette structure de chaussée a été modélisé dans le logiciel selon quatre scénarios; un revêtement d’enrobé bitumineux, un revêtement de béton armé continu (BAC), un revêtement de dalles courtes non armées non goujonnées (DCNANG) et un revêtement de dalles courtes non armées goujonnées (DCNAG). Les contraintes et les déformations liées aux soulèvements au gel de la chaussée à revêtement bitumineux ont été définies et ensuite appliquées sur les trois types de chaussées à revêtement de béton. Il a été possible de simuler la réaction des revêtements de béton face aux soulèvements au gel. Dans le cas où les contraintes liées aux soulèvements au gel de la chaussée bitumineuse ont été appliquées sur les trois types de chaussées de béton, les résultats montrent que la réduction de soulèvement est importante. Dans le cas où les déformations liées aux soulèvements au gel de la chaussée bitumineuse ont été appliquées sur les trois types de chaussées de béton, les résultats montrent que la réduction de soulèvement est aussi importante. Dans ces deux cas, une couche de matériau granulaire permettant de réduire l’exposition au gel d’un sol d’infrastructure gélif ne serait pas requise. Ces simulations montrent qu’un revêtement possédant une rigidité importante devrait être en mesure de limiter, en partie, la grandeur des soulèvements au gel prévus

Secondary metabolites a potential improvement for the economy of second generation biofuel production

The decreasing prices of oil ($29.44US – feb.2016) and natural gas ($1.97US– feb.2016) have significantly restrained the opportunity for the development of the second-generation biofuel industry. Numerous investigations focus on improving processes in order to improve the yield of biofuels. However, the latter being a commodity submitted to a strong competition by the fossil fuel industry, there is strong necessity to find other approaches allowing getting more revenues per tonne of converted biomass. Furthermore, despite the fact that the price of fossil fuels is decreasing, biomass still requires to be transported over long distances to reach a centralized conversion facility, thus, it is of outmost importance to get the most of this renewable feedstock. Secondary metabolites may represent an interesting way to generate complementary value to biofuels production. Extraction of secondary metabolites can 1) improve processes by removing undesirable compounds thus purifying the raw material (as an example by removing fermentation inhibitors) and 2) add an increased value by recovering high value compounds that could represent additional values as pharmaceuticals, cosmetics or food additives. Please click Additional Files below to see the full abstract

The isotope composition of inorganic Germanium in seawater and deep sea sponges

Although dissolved concentrations of germanium (Ge) and silicon (Si) in modern seawater are tightly correlated, uncertainties still exist in the modern marine Ge cycle. Germanium stable isotope systematics in marine systems should provide additional constraints on marine Ge sources and sinks, however the low concentration of Ge in seawater presents an analytical challenge for isotopic measurement. Here, we present a new method of pre-concentration of inorganic Ge from seawater which was applied to measure three Ge isotope profiles in the Southern Ocean and deep seawater from the Atlantic and Pacific Oceans. Germanium isotopic measurements were performed on Ge amounts as low as 2.6 ng using a double-spike approach and a hydride generation system coupled to a MC-ICP-MS. Germanium was co-precipitated with iron hydroxide and then purified through anion-exchange chromatography. Results for the deep (i.e. > 1000 m depth) Pacific Ocean off Hawaii (nearby Loihi Seamount) and the deep Atlantic off Bermuda (BATS station) showed nearly identical δ74/70Ge values at 3.19 ± 0.31 ‰ (2SD, n = 9) and 2.93 ± 0.10 ‰ (2SD, n = 2), respectively. Vertical distributions of Ge concentration and isotope composition in the deep Southern Ocean for water depth > 1300 m yielded an average δ74/70Ge = 3.13 ± 0.25 ‰ (2SD, n = 14) and Ge/Si = 0.80 ± 0.09 μmol/mol (2SD, n = 12). Significant variations in δ74/70Ge, from 2.62 to 3.71 ‰, were measured in the first 1000 m in one station of the Southern Ocean near Sars Seamount in the Drake Passage, with the heaviest values measured in surface waters. Isotope fractionation by diatoms during opal biomineralization may explain the enrichment in heavy isotopes for both Ge and Si in surface seawater. However, examination of both oceanographic parameters and δ74/70Ge values suggest also that water mass mixing and potential contribution of shelf-derived Ge also could contribute to the variations. Combining these results with new Ge isotope data for deep-sea sponges sampled nearby allowed us to determine a Ge isotope fractionation factor of -0.87 ± 0.37 ‰ (2SD, n = 12) during Ge uptake by sponges. Although Ge has long been considered as a geochemical twin of Si, this work underpins fundamental differences in their isotopic behaviors both during biomineralization processes and in their oceanic distributions. This suggests that combined with Si isotopes, Ge isotopes hold significant promise as a complementary proxy for delineating biological versus source effects in the evolution of the marine silicon cycle through time

The HAND-Q : Psychometrics of a New Patient-reported Outcome Measure for Clinical and Research Applications

Background: The perspective of the patient in measuring the outcome of their hand treatment is of key importance. We developed a hand-specific patient-reported outcome measure to provide a means to measure outcomes and experiences of care from the patient perspective, that is, HAND-Q. Methods: Data were collected from people with a broad range of hand conditions in hand clinics in six countries between April 2018 and January 2021. Rasch measurement theory analysis was used to perform item reduction and to examine reliability and validity of each HAND-Q scale. Results: A sample of 1277 patients was recruited. Participants ranged in age from 16 to 89 years, 54% were women, and a broad range of congenital and acquired hand conditions were represented. Rasch measurement theory analysis led to the refinement of 14 independently functioning scales that measure hand appearance, health-related quality of life, experience of care, and treatment outcome. Each scale evidenced reliability and validity. Examination of differential item functioning by age, gender, language, and type of hand condition (ie, nontraumatic versus traumatic) confirmed that a common scoring algorithm for each scale could be implemented. Conclusions: The HAND-Q was developed following robust psychometric methods to provide a comprehensive modular independently functioning set of scales. HAND-Q scales can be used to assess and compare evidence-based outcomes in patients with any type of hand condition.Peer reviewe

Evidence for oxygenic photosynthesis half a billion years before the Great Oxidation Event

The early Earth was characterized by the absence of oxygen in the ocean–atmosphere system, in contrast to the well-oxygenated conditions that prevail today. Atmospheric concentrations first rose to appreciable levels during the Great Oxidation Event, roughly 2.5–2.3 Gyr ago. The evolution of oxygenic photosynthesis is generally accepted to have been the ultimate cause of this rise, but it has proved difficult to constrain the timing of this evolutionary innovation. The oxidation of manganese in the water column requires substantial free oxygen concentrations, and thus any indication that Mn oxides were present in ancient environments would imply that oxygenic photosynthesis was ongoing. Mn oxides are not commonly preserved in ancient rocks, but there is a large fractionation of molybdenum isotopes associated with the sorption of Mo onto the Mn oxides that would be retained. Here we report Mo isotopes from rocks of the Sinqeni Formation, Pongola Supergroup, South Africa. These rocks formed no less than 2.95 Gyr ago in a nearshore setting. The Mo isotopic signature is consistent with interaction with Mn oxides. We therefore infer that oxygen produced through oxygenic photosynthesis began to accumulate in shallow marine settings at least half a billion years before the accumulation of significant levels of atmospheric oxygen