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This study was conducted to investigate the extent to which affectionate physical contact (i.e., cuddling) affects preschoolers’ and parents’ abilities to engage in theory-of-mind reasoning. We explored the hypothesis that if affectionate contact affected theory-of-mind, then preschoolers and parents who cuddled would outperform those who did not. To test this hypothesis, we recruited 44 preschool aged children (3.8-4.6-year-olds) and their primary caregivers. We found that children who cuddled with their primary caregiver during a storybook reading task performed significantly better on theory-of-mind tasks compared to children who did not receive a cuddle. Importantly, our findings support the contention that affectionate contact affected children’s performance on theory-of-mind related tasks specifically, but not performance on executive functioning or non-mental representation tasks. A secondary goal of this study was to explore whether any effects of affectionate contact would be mediated by functional polymorphisms of the oxytocin receptor gene (OXTR). Although we were unable to obtain a sample size that was sufficient to directly test this hypothesis, we found that parents homozygous for the G allele at rs2254298 were significantly better at decoding the affective mental states of others compared to those who carried at least one A allele. Thus, our results support the hypotheses that affectionate contact promotes children’s theory-of-mind reasoning abilities and that adult’s mental state decoding skills can be predicted by allelic variations on the OXTR gene. This study offers preliminary support for the role of affectionate contact and, separately, the oxytocinergic system on tasks related to theory-of-mind reasoning. These claims are discussed with respect to possible alternative explanations for our findings, as well as future directions to directly test the extent to which such experiential and psychobiological factors can affect theory-of-mind reasoning. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2013-08-15 14:13:54.174

Wet-work exposure has been recognized as a main risk factor for developing Irritant contact dermatitis of the hand. Duration and frequency of wet-work exposure are the key risk determinants, but there is still no reliable objective method to assess these factors in the workplace. The current study aimed to further validate a newly invented wet-work exposure monitor (WWEM) among four high risk occupational groups of hairdressers, florists, caterers and nurses. The WWEM, which consists of two similar thermocouples provides a real-time indication of the wetness of the finger by measuring the temperature changes when the finger is wet and subsequent cooling when the water evaporates from the skin. A suitable data analysis routine was constructed and direct observation was employed as the gold standard. Receiver Operating Characteristic (ROC) analysis was used to compare the results. In laboratory experiments, the most suitable wet-event threshold value, as a criterion to distinguish the wet and dry exposure periods was identified as 1.6°C (Mean+5SD of the “dry” data). Using this value sensitivity and specificity were 70% and 78%, respectively. An area under the curve (AUC) of 0.78 demonstrated a “high” accuracy for WWEM in lab experiments. Field testing in real occupational fields identified varying degrees of user acceptability and different wet-event threshold values to produce maximal sensitivity and specificity of the instrument. Among hairdressers, the WWEM showed a “moderate” accuracy at the threshold value of 1.37°C with an AUC of 0.62. For florists, the most suitable threshold value in the range of examined thresholds was 1.14°C with a “good” accuracy. Among a cohort of caterers, a threshold value of 1.6°C demonstrated a “hi gh” accuracy with an AUC of 0.72. The WWEM demonstrates the minimum value of the largest AUC for nurses. This is the minimum amount of accuracy among the four occupational groups. The figure is 0.52, achieved at a threshold value of 2.5°C. The WWEM enables the frequency and duration of wet-work exposure to be assessed in an objective manner rather than the current costly and unreliable subjective methods of direct observation and questionnaire. The results indicate that the WWEM has good sensitivity and high specificity in detecting exposure to wet-work. This device provides new experimental data on wetwork exposure and may be used in future as an educational tool to highlight the importance of wet-work exposure to both employees and employers.

L’étude du contact électrique quasi statique à plusieurs échelles permet de comprendre celui des micro-relais MEMS. Au cours de ce travail, une modélisation fine du contact est développée pour valider des lois de comportement établies à partir des mesures obtenues grâce à la mise au point de deux dispositifs expérimentaux originaux : la balance de précision, qui permet de réaliser un contact à l’échelle macroscopique entre barreaux croisés recouverts des films minces des matériaux à tester, et un nanoindenteur instrumenté pour la mesure électrique reproduisant un micro-contact identique à celui des micro-relais. Ils permettent tous deux de mener une étude comparative de différents échantillons en fonction de la force (de la dizaine de µN à quelques N), du courant (du µA à l’A), de l’état de surface (rugosité) ou encore du temps ; le contact étant caractérisé par sa résistance électrique. Ce travail concerne principalement le contact réalisé entre films minces en Au, matériau de contact de référence pour les applications micro-relais MEMS. L’étude des contacts de grande dimension a néanmoins été élargie à Ru, Rh, Pt et à l’alliage Au-Ni.Les résultats obtenus à l’aide de la balance de précision ont démontré la nécessité de prendre en compte l’influence de la configuration en film mince des matériaux de contact, tant du point de vue mécanique (rugosité) qu’électrique (répartition des lignes de courant). Leur comparaison à une modélisation statistique du contact rugueux donne des résultats satisfaisants. Cette approche a par ailleurs nécessité le développement d’un algorithme d’analyse d’image des relevés topographiques réalisés au microscope à force atomique, permettant ainsi de quantifier précisément les positions, taille et rayon de courbure de chaque aspérité de la surface.Les mesures effectuées à l’aide du nanoindenteur ont mis en évidence l’effet de la durée de fermeture des microcontacts sur la valeur de la résistance électrique. Le fluage des aspérités serait en partie responsable de la décroissance temporelle observée, aboutissant à des valeurs de résistance limite comparables à celles calculées à l’aide d'une modélisation numérique du contact entre des aspérités discrétisées et une sphère lisse. / The multi scale study of quasi static electrical contact is aimed at understanding those in MEMS microswitches. In this work, an accurate modeling of contact is developed to validate constitutive relations based on measurements obtained through the development of two original experimental set ups: a precision balance, which enables to perform a macroscopic contact between crossed roads coated with thin films of the materials to be tested, and a nanoindenter instrumented for electrical measurements reproducing microswitches contacts. They both allow a comparative study of different samples depending on the force (from μN to N), current (µA to A), surface condition (roughness) or time, while the contact is characterized through its electrical resistance. The measurements are obtained in the first place for gold, the reference contact material for MEMS microswitches applications. The study of large contacts was nevertheless extended to Ru, Rh, Pt and Au-Ni alloy.The results obtained using the precision balance showed the need to take into account the influence of the thin film configuration of contact materials, both in terms of mechanical (roughness) and electrical (distribution of current lines). Their comparison to a statistical model of rough contact gives satisfactory results. This approach also required the development of an image analysis algorithm of topographic maps obtained through atomic force microscopy. It allows quantifying precisely the position, height and radius of curvature of each surface asperity.Measurements made using the nanoindenter showed the effect of the time of closure of the micro contact on electrical resistance values. The creep of asperities may be partly responsible for the observed time decay, leading to limit resistance values comparable to those calculated using a numerical modeling of the contact between discretized asperities and a smooth sphere.

L’enjeu actuel pour les fabricants de turboréacteurs est de fournir des moteurs peu polluants tout en assurant un rendement élevé. Une solution consiste en une réduction significative du jeu entre le rotor aubagé et le stator. Toutefois, le fonctionnement à jeu très faible induit inévitablement des contacts pouvant engendrer des pertes d’aubes. De nombreuses études identifiant les phénomènes vibratoires se sont révélées insuffisantes pour appréhender le problème de contact rotor-stator. Afin de franchir un cap dans la compréhension du contact, ces travaux de thèse proposent de considérer l’influence des phénomènes se produisant lors d’un contact frottant aube-carter : l’usure et le comportement thermomécanique.D’abord des résultats d’essais de contact aube-carter sur un banc à échelle réelle sont analysés permettant d’observer clairement l’usure du carter et les échauffements à l’échelle locale du contact.Afin d’expliquer ces observations expérimentales, des simulations numériques sont réalisées. Les études de la dynamique d’aube apportent une explication sur les profils d’usure du carter. Des simulations thermomécaniques montrent une influence significative des dilatations thermiques au contact.Enfin, une étude numérique couplée d’une aube en contact avec un carter est menée, considérant l’usure du carter induite par la dynamique de l’aube en contact, les échauffements et les dilatations thermiques se produisant au contact aube-carter. L’influence de ces phénomènes sur la dynamique de l’aube est clairement démontrée notamment les variations de régime vibratoire et les conditions pouvant entrainer la divergence du système. / The issue for the turbojet engine designers is to make less polluting et more efficient engine. A solution is to reduce significantly the clearance between the rotating bladed disk and the casing. However, operating with a very tight clearance induces inevitably interactions which can lead to loses of blades. Many studies identifying the vibratory phenomena are appeared as insufficient to totally understand the problem of contact. To reach a milestone this work proposes the study of the influence of the local phenomena during a blade-casing rubbing contact: wear and thermomechanical behavior.At first, the results of a study of a blade-casing contact performed on an experimental compressor of a turbojet at a real scale are analyzed in order to clearly identify the wear of the casing and the heating at the contact.Numerical simulations are preformed to explain these experimental observations. A study of the blade dynamics can explain the wear pattern of the casing. Thermomechanical simulations highlight a significant influence of thermal expansions on the contact.A numerical study of the dynamics of a blade interacting with a casing is performed with the consideration of the wear induced by the contact and the heatings and thermal expansions occurring at the local contact. It clearly highlights the influence of these phenomena on the blade dynamics, notably the variations of vibratory behavior and the conditions which can lead to the divergence of the system.