NCube/papyrus huggingface dataset:
Sur une classe de structures kählériennes généralisées toriques

This thesis is about the problem of finding a natural notion of "scalar curvature" in generalized Kähler geometry. The approach taken here is to compute the moment map for the action of the group of hamiltonian diffeomorphisms on the space of generalized Kähler structures of symplectic type. Indeed, it is well known that the moment map for the restriction of this action to the space of ordinary Kähler structures can be naturally identified with the riemannian scalar curvature. We concern ourselves only with a certain class of generalized Kähler structures on toric manifolds which we denote by $DGK_{\omega}^{\mathbb{T}}(M)$ and which we recognize as being classified by the data of an antisymetric matrix $C$ and a real-valued strictly convex functions $\tau$ (exhibiting appropriate behavior on a neighborhood of the boundary of the moment polytope). This viewpoint makes obvious the fact that any toric Kähler structure can be deformed to a non-Kähler element of $DGK_{\omega}^{\mathbb{T}}(M)$, and we note that this deformation happens along one of the classes which were shown by R. Goto to be unobstructed. We identify sufficient conditions on a pair $(\tau,C)$ for it to define an element of $DGK_{\omega}^{\mathbb{T}}(M)$ and we show that in dimension 4, these conditions are also necessary. Following the adage "the moment map is the curvature" mentioned above, formulas for notions of "generalized Hermitian scalar curvature" and "generalized Riemannian scalar curvature" (in dimension 4) are obtained in terms of the function $\tau$. Finally, an expression for the generalized Riemannian scalar curvature in terms of the underlying bi-Hermitian structure is found in dimension 4. When compared with the results of the physicists Coimbra et al., our formula suggests a canonical choice for the dilaton of their theory.

Keyphrases: Generalized Kähler geometry, Toric geometry, Scalar curvature
Relating Dependent Terms in Information Retrieval

Search engine has become an integral part of our life. More than one-third of world populations are Internet users. Most users turn to a search engine as the quick way to finding the information or product they want. Information retrieval (IR) is the foundation for modern search engines. Traditional information retrieval approaches assume that indexing terms are independent. However, terms occurring in the same context are often dependent. Failing to recognize the dependencies between terms leads to noise (irrelevant documents) in the result. Some studies have proposed to integrate term dependency of different types, such as proximity, co-occurrence, adjacency and grammatical dependency. In most cases, dependency models are constructed apart and then combined with the traditional word-based (unigram) model on a fixed importance proportion. Consequently, they cannot properly capture variable term dependency and its strength. For example, dependency between adjacent words “black Friday” is more important to consider than those of between “road constructions”. In this thesis, we try to study different approaches to capture term relationships and their dependency strengths. We propose the following methods for monolingual IR and Cross-Language IR (CLIR): We re-examine the combination approach by using different indexing units for Chinese monolingual IR, then propose the similar method for CLIR. In addition to the traditional method based on words, we investigate the possibility of using Chinese bigrams and unigrams as translation units. Several translation models from English words to Chinese unigrams, bigrams and words are created based on a parallel corpus. An English query is then translated in several ways, each producing a ranking score. The final ranking score combines all these types of translations. We incorporate dependencies between terms in our model using Dempster-Shafer theory of evidence. Every occurrence of a text fragment in a document is represented as a set which includes all its implied terms. Probability is assigned to such a set of terms instead of individual terms. During query evaluation phase, the probability of the set can be transferred to those of the related query, allowing us to integrate language-dependent relations to IR. We propose a discriminative language model that integrates different term dependencies according to their strength and usefulness to IR. We consider the dependency of adjacency and co-occurrence within different distances, i.e. bigrams, pairs of terms within text window of size 2, 4, 8 and 16. The weight of bigram or a pair of dependent terms in the final model is learnt according to a set of features. All the proposed methods are evaluated on several English and/or Chinese collections, and experimental results show these methods achieve substantial improvements over state-of-the-art baselines.

Keyphrases: Information retrieval, Language modeling, Translation unit, CLIR, Dempster-Shafer theory, Term dependency, Discriminative model, Dependency strength
La prévalence de la malnutrition chez les enfants et adolescents hospitalisés

Today, malnutrition still goes undetected in paediatric hospitals. Inadequate nutritional status has been associated with poor clinical outcomes and has shown to increase annual hospital costs, thereby affecting both the patient and the health care system. In the litterature, the prevalence in paediatric patients of malnutrition is highly variable ranging from 2,5 to 51%. This is mostly due to the diversity of methods used to detect and assess nutritional status as well as the lack of consensus around one definition for paediatric undernutrition. Growing evidence indicates that the nutritional status of sick children deteriorates during the course of hospitalization and that unfavorable hospital practices, such as the absence of nutritional screening, may in fact be aggravating the situation. This thesis mainly focuses on highlighting the issue of pediatric malnutrition in hospitals and aims to critically discuss its prevalence as a function of the different research protocols, their clinical characteristics as well as the methodology used. A second objective was to identify hospital practices that may negatively affect the nutritional status of hospitalized children. Finally, following this comprehensive analysis of the litterature, the third goal was to develop a structured protocol for a multicenter study on pediatric malnutrition in Canada.

Keyphrases: Malnutrition, Hospitalized children, Anthropometry, Hospital Practices
Voir la guerre venir : la Première Guerre mondiale vue par The New York Times (1914-1917)

The United States adopted a stance of strict neutrality when the European war broke out in August 1914. Overall, the population's opinions on this stance were mixed. America's two years and a half neutrality redefined, through critical events and themes, the role of the United States in the European war. These events served to justify America's entry into World War I in April 1917 and put the country at the forefront of the international scene.  The American press during America's period of neutrality in the Great War has not been studied extensively. This study seeks to analyze the content of front-page articles and editorials in The New York Times (NYT) by comparing the evolution of themes and opinions with the traditional historiography of the American neutrality. The goal of this project is to depict the vision of the NYT in relation to the war,  in order to understand how the press managed to affect the public opinion and to discuss how the conflict slowly sunk into the lives of the American people. Some themes, such as the preparedness movement or the coverage of the German American community, provide great insight into how the perception of the war evolved throughout the American neutrality.  According to the traditional historiography, the sinking of the Lusitania on the 7th May 1915, was the first step toward the breaking of the American neutrality and the initiation of an authentic pro-ally loyalty. Our analysis of this period shows, however, that other events and themes were responsible for the end of the American neutrality. New questions emerge regarding the temporality of the neutrality and its nature. Was it as really benevolent and selfless as President Wilson had wished or was it only an illusion?

Keyphrases: The New York Times, Lusitania, Preparedness, First World War, American neutrality, Editorials, Press coverage
Photorealistic Surface Rendering with Microfacet Theory

Photorealistic rendering involves the numeric resolution of physically accurate light/matter interactions which, despite the tremendous and continuously increasing computational power that we now have at our disposal, is nowhere from becoming a quick and simple task for our computers. This is mainly due to the way that we represent objects: in order to reproduce the subtle interactions that create detail, tremendous amounts of geometry need to be queried. Hence, at render time, this complexity leads to heavy input/output operations which, combined with numerically complex filtering operators, require unreasonable amounts of computation times to guarantee artifact-free images. In order to alleviate such issues with today's constraints, a multiscale representation for matter must be derived.  In this thesis, we derive such a representation for matter whose interface can be modelled as a displaced surface, a configuration that is typically simulated with displacement texture mapping in computer graphics. Our representation is derived within the realm of microfacet theory (a framework originally designed to model reflection of rough surfaces), which we review and augment in two respects. First, we render the theory applicable across multiple scales by extending it to support noncentral microfacet statistics. Second, we derive an inversion procedure that retrieves microfacet statistics from backscattering reflection evaluations. We show how this augmented framework may be applied to derive a general and efficient (although approximate) down-sampling operator for displacement texture maps that (a) preserves the anisotropy exhibited by light transport for any resolution, (b) can be applied prior to rendering and stored into MIP texture maps to drastically reduce the number of input/output operations, and (c) considerably simplifies per-pixel filtering operations, resulting overall in shorter rendering times. In order to validate and demonstrate the effectiveness of our operator, we render antialiased photorealistic images against ground truth. In addition, we provide C++ implementations all along the dissertation to facilitate the reproduction of the presented results. We conclude with a discussion on limitations of our approach, and avenues for a more general multiscale representation for matter.

Keyphrases: Microfacet Theory, Rendering, Photorealism, Antialiasing, Filtering
Advances in scaling deep learning algorithms

Deep learning algorithms are a new set of powerful methods for machine learning. The general idea is to combine layers of latent factors into hierarchies. This usually leads to a higher computational cost and having more parameters to tune. Thus scaling to larger problems will require not only reducing their computational cost but also improving regularization and optimization. This thesis investigates scaling from these three perspectives.  We first study the problem of reducing the computational cost of some deep learning algorithms. We propose methods to scale restricted Boltzmann machines (RBM) and denoising auto-encoders (DAE) to very high-dimensional sparse distributions. This is important for applications of deep learning to natural language processing. Both methods (Dauphin et al., 2011; Dauphin and Bengio, 2013) rely on importance sampling to subsample the learning objective of these models. We show that this greatly reduces the training time, leading to 2 orders of magnitude speed ups on several benchmark datasets without losses in the quality of the model.  Second, we introduce a powerful regularization method for deep neural nets. Experiments have shown that proper regularization is in many cases crucial to obtaining good performance out of larger networks (Hinton et al., 2012). In Rifai et al. (2011), we propose a new regularizer that combines unsupervised learning and tangent propagation (Simard et al., 1992). The method exploits several geometrical insights and was able at the time of publication to reach state-of-the-art results on competitive benchmarks.  Finally, we consider the problem of optimizing over high-dimensional non-convex loss surfaces like those found in deep neural nets. Traditionally, the main difficulty in these problems is considered to be the abundance of local minima. In Dauphin et al. (2014a) we argue, based on results from statistical physics, random matrix theory, neural network theory, and empirical evidence, that the vast majority of critical points are saddle points, not local minima. We also propose a new optimization method for non-convex optimization.

Keyphrases: Deep learning, Neural networks, High-dimensional non-convex optimization, Boltzmann machines, Auto-encoders
Effets des recuits ultra-rapides (10^5 K/s) sur la formation des siliciures métalliques en phase solide

The synthesis of metal silicides in the form of ultra-thin films remains a major issue in CMOS technology. Controlling the thermal budget to limit dopant diffusion is essential and ultra-rapid annealing techniques are commonly used. In this context, the nanocalorimetry technique is used in situ to study Ni silicides phase formation at heating rate as high as 10^5 K/s. Ni films from 9.3 nm to 0.3 nm are carried out on calorimeters with either a-Si or Si(100) substrate. Ex situ temperature-resolved x-ray diffraction, scanned at low heating rate (3 K/s), is used in order to compare the phase sequence with the ones obtained at ultra-high heating rates. First, the use of c-NC calorimeters equipped with a Si(100) substrate, 340 nm thick, results in a major challenge. An abnormal endothermic signal is measured at high temperature. Results show that microdefects in the SiNx membrane create short circuits between the Pt heating strip of the calorimeter and the metal sample. This phenomenon decreases with the thickness of the metal sample and has no effect below 400 °C. Below this temperature the Si charge carriers are not activated. Then, the heat flow signal was corrected as a function of the temperature with an uncertainty of 12 ° C. In regard to the formation of Ni silicides at ultra-high heating rates, the study shows that the phase sequence is changed. On Si(100) substrate, the metal rich phases such as Ni2Si and theta -phase are no longer detected. Also, a solid state amorphization is favored at the beginning of the reaction. The enthalpies of formation for layers thinner than 10 nm are generally higher, up to 66 %, than those listed in literature for thick layers. Moreover, the calorimetric measurements clearly show an endothermic signal at high temperature, revealing a competition between the reaction of phase formation and the layer agglomeration. For sample annealed at 3 K/s on Si(100), the critical thickness as described by Zhang and Luo, is observed around 4 nm of Ni. A model is proposed in order to explain the increased stability when the layer thicknesses decrease. It is based on the fact that the diffusion of atoms is harder when grain sizes decrease. It also explains why the endothermic signals in nanocalorimetry shift toward higher temperatures when the layer thickness decreases. In addition, a second critical thickness of about 1 nm is noted. Below, it seems that only one phase forms, presumably the NiSi2.

Keyphrases: Films minces, Nickel, Metal silicides, Nanocalorimetry, Ultra-fast annealing, Thin films
Association entre les affections buccodentaires et le cancer colorectal : une revue et synthèse de la littérature

Background: Chronic periodontitis and tooth loss are chronic oral conditions that, in recent decades, have been implicated in the occurence of certain types of cancer. In this review, we address the question of whether colorectal cancer is associated with these oral conditions. Results: Epidemiological studies evaluating a potential association between periodontitis, tooth loss and colorectal cancer are scarce. However, several mechanisms argue in favor of this association, notably inflammation, nutrition and possibly infection by specific bacteria, as suggested by this literature review.

Keyphrases: Fusobacterium nucleatum, Chronic periodontitis, Periodontal disease, Tooth loss, Colorectal cancer, Epidemiology, Etiology
Utilisation d’agrafes chirurgicales dans le suivi de tumeurs hépatiques appliquée à des
traitements de radiochirurgie stéréotaxique par CyberKnife

Recent progress in stereotactic body radiation therapy allows an ever larger number of people to receive non-invasive treatment for liver cancer. One of the methods that were developed involves tracking the tumor’s movements, using radio-opaque markers which are inserted into the liver of the patient, with the help of the tracking system of the CyberKnife. However, the insertion of these markers is sometimes too invasive for patients with poor liver condition. These patients often have a history of surgery which allows the tracking of surgical clips that are already present in the liver as a surrogate for the tumor. This new approach to treating liver cancer is investigated in the present study in order to identify the optimal parameters for a better practice of this therapy. An anthropomorphic phantom experiment lead to the conclusion that the clip contrast in the tissue increases with an increase of the two imaging parameters (kV and mA of the x-ray tube). In addition, the error that was made on the identification of the position of clips by the CyberKnife system was measured as being slightly superior to the error on platinum marker positions (approximately 1 mm vs less than 1 mm). This error is considered acceptable in the context of this particular type of treatment. Finally, a gamma analysis of the dosimetric impact of clip tracking shows that it is approximately equivalent to that of platinum marker tracking. From these observations, we conclude that the treatment of liver tumors using surgical clips is valid and can be improved following this study’s clinical recommendations.

Keyphrases: Cancer, CyberKnife, liver, surgical clips
Cohabitation entre les activités résidentielles et prostitutionnelles du quartier Hochelaga-Maisonneuve

This study aims to explore the universe of the cohabitation of street prostitution and residential activities in the district of Hochelaga-Maisonneuve. The research specifically focusses on the impact of such practices on theresidential environment. Rooted in a phenomenological perspective, the study is based on the speech of 35 key players reporting their cohabitation experiences. These actors are merchants, residents of the area, proximity stakeholders as well as sex workers. Through the analysis of interviews and of a hundred hours of field observation in the company of Montreal Police Service officers, the study outlines the cohabitation-related issues, introduces the idea of anegotiated tolerance and portrays the street narcoprostitution specific to Hochelaga-Maisonneuve district. In the light of our observations, we understand that it is difficult to separate prostitution activities and addiction habits. More precisely, street prostitution, the presence of cracks houses, public consumption and intoxication of individuals as well as gatherings of underground lifestyle people are all elements which are very often inter-connected and pointed out by the interviewed actors. The study highlights the impacts of these elements on theresidential neighborhood.

Keyphrases: narcoprostitution, crackhouse, cohabitation, Hochelaga-Maisonneuve, prostitution, street prostitution, methodology qualitative, grounded theory, crack house
Lectura feminista de las Comedias bárbaras de Ramón del Valle-Inclán : Lilith y las mujeres en la decadencia del patriarcado

This study presents an innovative interpretation of the Comedias bárbaras  (« Águila de blasón », « Romance de lobos » and « Cara de plata », 1907-1908-1922) by Ramón María del Valle-Inclán (Spain, 1866-1936) that differs from the dominant reception. Inspired by gender studies, this work revisits the trilogy by focussing on the feminine characters’ perspectives in contrast to the omnipresence of the myth of Lilith (or the legendary idea of sin being originated by a demon woman). Analyzing gender relations in the plot appears essential since the character of Don Juan Manuel Montenegro is also a version of the legendary Don Juan. Moreover, by giving a special attention to the distinct discourses about him and the grotesque elements, we perceive in the character’s treatment a criticism that goes beyond the historical context, revealing a much more universal dimension that points out the very logics of the patriarchal system and the legitimacy of power. All of these considerations allow us to better appreciate those aspects of the trilogy that brings it closer to the further aesthetic of the esperpento. This contemporary interpretation establishes a dialogue with some of the central debates around the work since its first publication (representability, literary genre, unity of the trilogy, classification) and revitalizes its reception in the XXI century, showing the fascinating contemporary relevance of the autor’s theater.

Keyphrases: Comedias bárbaras, Lilith, esperpento, Don Juan, feminism, dramatic character
La modulation du métabolisme cellulaire par l'E3 Ubiquitine Ligase MARCH-1

Relocation and degradation mediated by ubiquitination are used by the cell to control the localization and the expression of proteins. E3 ubiquitin ligase MARCH1 is known to be involved in post-translational regulation of MHC-II and CD86. In this thesis, we suggest an additional role to MARCH1. Our experimental results lead us to believe that MARCH1 may modulate cellular metabolism by promoting the relocation and degradation of enzymes involved in glycolysis. The vast majority of cells generate ATP from oxidative phosphorylation in presence of oxygen. In a hypoxic environment, the latter is non-functional and the cell must use the anaerobic glycolysis to produce ATP. A cancerous cell requires more energy due to increased biomass and its uncontrolled proliferation. To meet these needs, it maximizes its energy production regardless of oxygen concentrations. Many studies have shown that aerobic glycolysis is preferred to oxidative phosphorylation in cancer cells, even if the two pathway are used simultaneously; it is described as the Warburg effect. Similar modification of the cellular metabolism is also found in immune cells after an activation signal to fulfill the cell functions. Here we show that the maximal mitochondrial respiration, the respiratory reserves and the maximal glycolysis are reduced in antigen-presenting cells that express MARCH1. Furthermore, we showed that MARCH1 can be localized on the mitochondria to interact with it’s target. Finally, we quantified the expression of Eno1 and LDHB by Western blot to show an increased expression of these enzymes in the absence of MARCH1. Thus, we discuss the benefits of the expression reduction of MARCH1 in an inflammatory context, following the activation of antigen presenting cells. This phenomenon would allow a better antigen presentation, an increased energy production and a greater resistance to ROS, produced during the inflammatory response.

Keyphrases: MARCH1