NCube/papyrus huggingface dataset:
Essays on skills and productivity

Why should we hire you? This question is almost always expected when going for a job interview. However, it is not obvious to agree on a standard answer to it. One formula that is often recommended is to share experiences that highlight the skills relevant to the position offered. No need to say that each job seeker is free to say what he wants. Skills are what employers are after. Although a minimum educational degree may be required for some positions, what matters is to be able to perform the duties associated with the proposed position. Education systems are built precisely to develop the skills employers are looking for. Determining whether these skills were indeed acquired at the end of these educational studies is another question.  My research uses theoretical and empirical, microeconomics and macroeconomics methods of analysis to examine various economic issues related to skills. I approach the notion of skills from different angles and in different contexts: productive skills not observable on the labor market and differentiated skills between immigrants and natives. This thesis compiles two essays in labor economics: the objective is to help understand how skills can affect the well-being of economic agents, but also their choices, whether these skills are observable or not.  The first chapter addresses the issue of the transparency of productive skills. Productive skills that are not ex ante observed by employers, are learnt throughout workers’ experience: this learning process affects the mobility of workers and especially the risk of layoff they face. In the second chapter, skills are equated with comparative advantages. This section looks more specifically at the impact of the entry of immigrants on the public finances of the host country. The conclusion is that the relative labor efficiency of immigrants is the factor with the largest marginal impact.

Keyphrases: Skills, Labor Mobility, Uncertainty, First Job, Survival Analysis, Immigration, Fiscal Policy, Sustainable Debt, Dette Soutenable
Forme et évolution des barres branchiales et des osselets de la classe Enteropneusta (Phylum Hemichordata)

The phylum Hemichordata forms, with Echinodermata, the group Ambulacraria that in turns forms with Chordata, the Deuterostomia. Among deuterostomes, the hemichordate class Enteropneusta is often viewed as the group that most closely resembles the last common ancestor of deuterostomes. Enteropneusts indeed share many traits with the other two deuterostome phyla and by studying them, we can infer the ancestral states of those traits. In the first chapter, I present the general morphology of hemichordates and their relationships with the other two deuterostome phyla. I also discuss the shared traits between the hemichordates, the echinoderms and the chordates. Last, I present the varied shapes that hard parts can take in animals, with a focus on deuterostomes. In chapter two, I describe the shape and mineral composition of ossicles in eight enteropneust species. This study is a major leap in our understanding of biomineralization in Hemichordata since up to this point ossicles were only described in two species and the mineral composition determined for only one. I discuss these results in an evolutionary context since hemichordate ossicles are probably homologous with echinoderm skeletal ossicles. This chapter is significant because it provides a hypothesis on the origin of ossicles in the last common ancestor of ambulacrarians.  In chapter three, I quantify the level of asymmetry of the pharyngeal slits in populations of two species of enteropneusts and the invertebrate cephalochordate Branchiostoma floridae. We found that adults of these species display fluctuating asymmetry in the gills and that this asymmetry is lower in filter feeding.  This is significant because it supports the hypothesis that filter feeding is an ancestral feature of deuterostomes and that the loss of this function increases developmental noise, vestigiality, or loss of the gills. In chapter four, I use X-ray microtomography to describe the enteropneust Balanoglossus occidentalis that was heretofore a nomen nudum. This new technique is compared with traditional histology to show that it is a viable tool in hemichordate taxonomical studies. In chapter five, I present a few experiments that had to be excluded from the other chapters because they gave negative, unpublishable results. I discuss the probable causes of their failures and potential ways to solve these issues for those who would want to pursue them further. Finally, I summarise the results of the previous chapters to show how studying hemichordates can still teach us a lot about the origin and evolution of the better studied deuterostome phyla.

Keyphrases: Deuterostomia, Hemichordata, Enteropneusta, Ambulacraria, Chordata, Biomineralization, Dermal ossicles, Fluctuating asymmetry, Taxonomy, Evolution
Le sommeil des enfants : questions méthodologiques, développementales et familiales

The overall objective of this thesis was to contribute new empirical knowledge on children's sleep assessed using actigraphy among typically-developing children.  The first article aimed to investigate the possibility for studies to use actigraphic data for which a sleep diary would not be available to guide the scoring of the data. The sample was composed of 60 children aged 6 to 10 years who wore an actigraph for 3 to 7 days and whose mothers completed a sleep diary for the same period. Actigraphic data were analyzed using two scoring conditions (with and without diary). The results suggest that the two conditions lead to similar results, virtually identical at the group level, but not interchangeable at the intra-individual level. This paper leads to the recommendation of parsimonious use of actigraphic data analyzed without a sleep diary. The second article aimed to study the developmental patterns of sleep in the preschool period. The sample included 128 children who wore an actigraph at 2, 3, and 4 years of age and for which the growth curves of five sleep indices were modeled using multi-level analyses. The results demonstrated a linear decrease in nighttime, daytime and 24-hour total sleep duration as well as a linear increase in the proportion of sleep taking place during the night and in sleep efficiency. This study confirms that developmental changes occur in several sleep variables during the preschool period and helps to provide quantitative points of reference regarding these changes. The third article aimed to examine different aspects of the father-child relationship as potential predictors of inter-individual differences in sleep growth curves during the preschool period. For 67 children, sleep growth curves between 2 and 4 years were estimated and the quality of father-child interactions as well as paternal mind-mindedness (fathers’ tendency to comment on child’s presumed mental states) were assessed by observation at 18 months. Fathers also completed a questionnaire assessing their involvement with their child at the age of 2 years. The results showed no significant association between sleep growth curves parameters and the degree of father involvement or the quality of father-child interactions. However, children whose fathers made more appropriate comments about their mental states at 18 months had a higher proportion of nighttime sleep as well as shorter daytime sleep duration and shorter 24-hour total duration at 2 years. In addition, these children subsequently exhibited less rapid changes in these sleep variables between 2 and 4 years. This paper suggests that children exposed to higher levels of paternal mind-mindedness appear to achieve more mature sleep patterns earlier in their development.

Keyphrases: Child sleep, Actigraphy, Sleep diary, Development, Preschool, Father-child relationship, Mind-mindedness
Différences individuelles et traitement visuel des fréquences spatiales

The contrast sensitivity function – the curve defining the way in which sensitivity differs according to spatial frequencies – was first measured in 1956 (Schade, 1956). The contrast sensitivity function differs from person to person and, although it was observed over 60 years ago, some factors which have an impact on these individual differences are not well understood.  The Campbell-Robson figure is a sinusoidal grating on which the spatial frequency varies on the x axis and contrast varies on the y axis, resulting in a perceived curve, between the grating and the perceived gray area of the grating, directly on the figure. If this figure contained information on the contrast sensitivity function, it would have been useful to develop a quick method to measure it. However, the results of article 1 show that there is little information on the contrast sensitivity function contained in the Campbell-Robson chart.   The way in which contrast sensitivity matures is not well understood. Because anterior studies used, among other things, different methods and tasks, the results they report vary greatly and are often contradictory. We have studied the question in article 2, using an objective method to measure contrast sensitivity for a large array of spatial frequencies (0.5 to 30 cycles per degree) and a large span of ages (4 to 27 years). Instead of using age as a categorial variable by separating the participants in age bins, we used a local regression technique (LOESS) in order to use age as a continuous variable and obtain a more precise estimate of the maturation age of contrast sensitivity. Results show that sensitivity becomes similar to an adult’s around 12 years old for low and high spatial frequencies, and around 17 years old for mid-range spatial frequencies. Other than age, the culture in which a person grows up is another factor that could have an impact on contrast sensitivity. In article 3, we verified the effect of culture on the contrast sensitivity function by measuring it using two different methods in Chinese and Canadian participants. Results don’t show that the contrast sensitivity function differs between the two cultures. Because of intercultural differences in ocular fixations on faces, we further verified if there are differences in the spatial frequencies contained in the internal representations of faces in the two cultures. Our results show that Chinese participants use lower spatial frequencies and Canadian participants use higher spatial frequencies when identifying faces. In sum, the results presented in this thesis help better understand individual differences in contrast sensitivity.

Keyphrases: Contrast sensitivity, Spatial frequencies, Face recognition, Individual differences, Cultural differences, Contrast sensitivity function, Bubbles
Le sommeil et les fonctions exécutives après un traumatisme crânio cérébral léger à l’âge préscolaire

Mild traumatic brain injury (mTBI) is a highly prevalent and serious public health concern.  Epidemiological data indicate that preschoolers (i.e., children under 5 years of age) are at especially high risk of sustaining TBI, yet few studies targeted this age group. This is of concern given that the brain is still immature in the early years of life, and children are at the beginning of their development, with few consolidated skills. The overall objective of this thesis is to expand our understanding of the impact of preschool mTBI, specifically on sleep and executive functioning. The thesis includes two empirical articles. The first article aimed to investigate sleep and its predictors in preschoolers with mTBI. The sample included 225 children, aged 18 to 60 months, divided into three groups: children with mTBI (n = 85), children with orthopedic injury (n = 58) and typically developing children (n = 82). Six months post-injury, parents were asked to fill out the Sleep scale from the Child Behavior Checklist, and children wore an actigraph for five days. No group differences were found in parental ratings of sleep problems or for nighttime sleep duration and sleep efficiency, as measured by actigraphy. However, preexisting sleep disturbances and brain injury resulting in alteration of consciousness were identified as predictors of poorer sleep six months post-injury in the mTBI group. The aim of the second article was to investigate executive functions six months post-injury in the same cohort of preschoolers, and to determine the role of sleep in the links between mTBI and executive functioning. Children with mTBI (n = 84) and typically developing children (n = 83) were included in the analyses. There were no significant group differences on measures of inhibition and cognitive flexibility six months post-injury. However, relative to controls, children with mTBI and shorter nighttime sleep duration or increased sleep problems exhibited poorer executive functions. This thesis allows a better understanding of the factors associated with sleep disturbance after preschool mTBI. In addition, the results highlight the importance of documenting sleep in preschoolers with mTBI, as sleep difficulties place children at risk for later executive dysfunction, which may subsequently impact other spheres of functioning.

Keyphrases: Cognition, Traumatic brain injury, Concussion, Pediatric, Children, Preschoolers, Sleep, Actigraphy, Executive functions
Les troubles psychotiques chez les enfants agressés sexuellement

In the last decade, several studies identified child sexual abuse as a risk factor for psychotic disorders. However, few longitudinal studies addressed the development of psychotic disorders in sexually abused children and adolescent. Previous studies mostly relied on retrospective designs, studying childhood trauma in adults with psychotic disorders, which limits our comprehension of the development of psychotic disorders in sexually abused children. The present thesis aims to achieve a better understanding of the development of psychotic disorders in youths who received a corroborated report of sexual abuse by the DYP. The first article aims to document the prevalence of psychotic disorders in sexually abused youth between the time of the first corroborated report of sexual abuse and the beginning of adulthood. Administrative databases of 882 youths who received a corroborated report of sexual abuse by the DPY were compared to 882 youths from the general population over a 13-year period. Conditional generalized linear mixed models reveal that sexually abused youth were 10 times more at risk to receive a diagnosis for a psychotic disorder than the general population. The second article documents the developmental trajectory of psychotic disorders following sexual abuse in terms of age at onset. The methods used are the same as the first article. Survival analysis reveal that sexual abuse and substance misuse are associated to the age at onset of psychotic disorder. Thus, studied youth are more at risk of receiving their first diagnosis of psychotic disorder early in their development when they received a corroborated report of sexual abuse or when they received a diagnosis for substance misuse. When the groups are compared separately, substance misuse is associated to the age at onset of psychotic disorder only in sexually abused youth. 8 The third article has an exploratory nature and aims to identify the psychological factors implied in the development of psychotic disorders in sexually abused youth. A first objective is to identify which psychological factors cooccur with psychotic disorder; a second objective is to identify which factors predicts psychotic disorders. For this article, only the sample of sexually abuse youth is used. Logistic regressions reveal that personality disorders are significantly associated to psychotic disorders. Youths with a diagnosis of personality disorders are 10 times more at risk of receiving also a diagnosis of psychotic disorder, regardless of the order in which they received either diagnosis. Intellectual disability and substance misuse are identified as factors who predict the development of psychotic disorders. The theoretical contributions of the present thesis to the literature on the association between childhood sexual abuse and psychotic disorders as well as the clinical implications for intervention and prevention programs offered to this population are discussed.

Keyphrases: childhood sexual abuse, psychotic disorder, developmental trajectories, etiology, longitudinal study, administrative databases
Is a picture worth a thousand words? : the development and validation of a picture-based knowledge transfer tool for university students

This thesis documents the development and validation of a picture-based mental health Knowledge Transfer tool for university students, named the PicMH-U. As a knowledge transfer tool, the PicMH-U was developed with the participation of the potential users (stakeholders): Canadian university students. The information it seeks to communicate is the mental health difficulties that have been found to most affect Canadian university students – as assessed by the 2016 Enquête sur la Santé Psychologique Étudiante – along with psychosocial resources they can access to seek assistance. This information and population are used in order to address the demonstrated alarming rate of mental health difficulties among university students and need for mental health awareness and intervention. The objectives for this thesis are two-fold: 1) to describe the state of the field of using images to communicate mental health/psychological research to North American adults; and 2) to develop and validate a mental health knowledge transfer/mobilization (KT) tool for a section of the adult population: university students. The first objective was satisfied through a systematic review (Article 1; Chapter 3) and the second objective through consultation with stakeholders (Chapter 2) and a longitudinal randomized controlled trial (Article 2; Chapter 4). The articles in this thesis have been submitted to peer-reviewed journals but are currently unpublished. Results from the systematic review (SR) indicate that experimental research on image-based mental health communication to North American adults is limited to tobacco use and control. The SR found that Picture Warning Labels spurred more negative affect and more conversations about the Health Warning Labels, were rated as more effective at encouraging quitting, and increased actual quit behaviors. Secondly, the randomized controlled trial found that the PicMH-U (image condition) had better results on tests of short-term, long-term, prompted and free recall, but not on user satisfaction, intention to use services, or actual use of services when compared to the text condition. This thesis contributes to the advancement of the field of picture-based communication, knowledge transfer and community mental health by researching an intervention often used in community practice but not commonly validated by experimental research. By validating the use of the picture-based mental health tool among university students, this thesis aims to provide empiric evidence to support the use of picture-based communication methods within mental health.

Keyphrases: knowledge transfer, knowledge mobilization, pictorial superiority effect, images, graphic medicine, mental health, university students, communication, art
Applications des structures algébriques associées aux systèmes intégrables

This thesis in three parts groups research work under the theme of the symmetries underlying integrable systems and the algebraic structures that encodes them. A first part illustrates how orthogonal polynomials, a type of special function, appear in the representation theory of various algebraic structures associated to symmetries. The second part focuses on an algebraic generalization of the classical Heun operator that leads to new algebraic structures with applications in signal processing and in the study of integrable systems. The last part concerns the formulation of a framework in the language of algorithmic information theory the enables a mathematical definition for the notion of emergence.

Keyphrases: Algebraic structures, Symmetries, Integrability, Orthogonal polynomials, Heun operators, Emergence
Primes with a missing digit : distribution in arithmetic progressions and sieve-theoretic applications

The theme of this thesis is to understand the distribution of prime numbers, which is a central topic in analytic number theory. More precisely, we prove Bombieri-Vinogradov type theorems for primes with a missing digit in their b-adic expansion for some large positive integer b. The proof is based on the circle method, which relies on the Fourier structure of the integers with a missing digit and the exponential sums over primes in arithmetic progressions. Combining our results with the semi-linear sieve, we obtain an upper bound and a lower bound of the correct order of magnitude for the number of primes of the form p=1+m^2+n^2 with a missing digit in a large odd base b.

Keyphrases: Analytic Number Theory, Sieve Methods, Exponential Sums, Fourier Transforms, Circle Method, Missing Digit
Quasi second-order methods for PDE-constrained forward and inverse problems

Computer-aided design (CAD), visual effects, robotics and many other fields such as computational biology, aerospace engineering etc. rely on the solution of mathematical problems. In most cases, computational methods are used to solve these problems. The choice and construction of the computational method has large impact on the results and the computational efficiency. The structure of the problem can be used to create methods, that are faster and produce qualitatively better results than methods that do not use the structure. This thesis presents three articles with three new computational methods tackling partial differential equation (PDE) constrained simulation and optimization problems.  In the first article, we tackle the problem of energy dissipation of common fluid solvers in visual effects. Fluid solvers are ubiquitously used to create effects in animated shorts and feature films. We present a time integration scheme for incompressible fluid dynamics which preserves energy better than many previous methods. The presented method has low overhead and can be integrated into a wide range of existing methods. The improved energy conservation leads to noticeably more dynamic animations.  We then move on to computational design whose goal is to harnesses computational techniques for the design process. Specifically, we look at sensitivity analysis, which computes the sensitivities of the simulation result with respect to the design parameters to automatically optimize the design. In this context, we present an efficient way to compute the Gauss-Newton search direction, leveraging modern sparse direct linear solvers. Our method reduces the computational cost of the optimization process greatly for a certain class of inverse design problems.  Finally, we look at topology optimization using machine learning techniques. We ask two questions: Can we do mesh-free topology optimization and can we learn a space of topology optimization solutions. We apply implicit neural representations and obtain structurally sensible results for mesh-free topology optimization by guiding the neural network during optimization process and adapting methods from finite element based topology optimization. Our method produces a continuous representation of the density field. Additionally, we present learned solution spaces using the implicit neural representation.

Keyphrases: Gauss-Newton, Fluid simulation, Advection-reflection, Sensitivity analysis, Computational design, Implicit neural representations, Topology optimization, Solution space