Flying fruit flies (Drosophila melanogaster) locate a concealed appetitive odour source most accurately in environments containing vertical visual contrasts (Frye et al, 2003). To investigate how visuomotor and olfactory responses interact to cause this phenomenon, I implement a tracking system capable of recording flies’ flight trajectories in three dimensions. I examine free-flight behaviour in three different visual environments, with and without food odour present. While odour localisation is facilitated by a random chequerboard pattern compared to a horizontally striped one, a single vertical landmark also facilitates odour localisation, but only if the odour source is situated close to the landmark. I implement a closed-loop systems-level model of visuomotor control consisting of three parallel subsystems which use wide-field optic flow cues to control flight behaviour. These are: an optomotor response to stabilise the model fly’s yaw orientation; a collision avoidance system to initiate rapid turns (saccades) away from looming obstacles; and a speed regulation system. This model reproduces in simulation many of the behaviours I observe in flies, including distinctive visually mediated ‘rebound’ turns following saccades. Using recordings of real odour plumes, I simulate the presence of an odorant in the arena, and investigate ways in which the olfactory input could modulate visuomotor control. In accordance with the principle of Occam’s razor, I identify the simplest mechanism of crossmodal integration that reproduces the observed pattern of visual effects on the odour localisation behaviour of flies. The resulting model uses the change in odour intensity to regulate the sensitivity of collision avoidance, resulting in visually mediated chemokinesis. Additionally, it is necessary to amplify the optomotor response whenever odour is present, increasing the model fly’s tendency to steer towards features of the visual environment. This could be viewed as a change in behavioural context brought about by the possibility of feeding. A novel heterogeneous visual environment is used to validate the model. While its predictions are largely borne out by experimental data, it fails to account for a pronounced odour-dependent attraction to regions of exclusively vertical contrast. I conclude that visual and olfactory responses of Drosophila are not independent, but that relatively simple interaction between these modalities can account for the observed visual dependence of odour source localisation.

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

Because games set in persistent virtual game worlds (VGWs) have massive numbers of players, these games need methods of characterisation for playable characters (PCs) that differ from the methods used in traditional narrative media. VGWs have a number of particularly interesting qualities. Firstly, VGWs are places where players interact with and create elements carrying narrative potential. Secondly, players add goals, motives and driving forces to the narrative potential of a VGW, which sometimes originates from the ordinary world. Thirdly, the protagonists of the world are real people, and when acting in the world their characterisation is not carried out by an author, but expressed by players characterising their PCs. How they can express themselves in ways that characterise them depend on what they can do, and how they can do it, and this characterising action potential (CAP) is defined by the game design of particular VGWs. In this thesis, two main questions are explored. Firstly, how can CAP be designed to support players in expressing consistent  characters in VGWs? Secondly, how can VGWs support role-play in their rule-systems? By using iterative design, I explore the design space of CAP by building a semiautonomous agent structure, the Mind Module (MM) and apply it in five experimental prototypes where the design of CAP and other game features is derived from the MM. The term semiautonomy is used because the agent structure is designed to be used by a PC, and is thus partly controlled by the system and partly by the player. The MM models a PC's personality as a collection of traits, maintains dynamic emotional state as a function of interactions with objects in the environment, and summarises a PC's current emotional state in terms of `mood'.   The MM consists of a spreading-activation network of affect nodes that are interconnected by weighted relationships.  There are four types of affect node: personality trait nodes, emotion nodes, mood nodes, and sentiment nodes. The values of the nodes defining the personality traits of characters govern an individual PC's state of mind through these weighted relationships, resulting in values characterising for a PC's personality. The sentiment nodes constitute emotionally valenced connections between entities. For example, a PC can `feel' anger toward another PC. This thesis also describes a guided paper-prototype play-test of  the VGW prototype World of Minds, in which the game mechanics build upon the MM's model of personality and emotion. In a case study of AI-based game design, lessons learned from the test are presented. The participants in the test were able to form and communicate mental models of the MM and game mechanics, validating the design and giving valuable feedback for further development. Despite the constrained scenarios presented to test players, they discovered interesting, alternative strategies, indicating that for game design the `mental physics' of the MM may open up new  possibilities.The results of the play-test influenced the further development of the MM as it was used in the digital VGW prototype the Pataphysic Institute. In the Pataphysic Institute the CAP of PCs is largely governed by their mood. Depending on which mood  PCs are in they can cast different `spells', which affect values such as mental energy, resistance and emotion in their targets. The mood also governs which `affective actions' they can perform toward other PCs and what affective actions they are receptive to. By performing affective actions on each other PCs can affect each others' emotions, which - if they are strong - may result in sentiments toward each other. PCs' personalities govern the individual fluctuations of mood and emotions, and define which types of spell PCs can cast. Formalised social relationships such as friendships affect CAP, giving players more energy, resistance, and other benefits. PCs' states of mind are reflected in the VGW in the form of physical manifestations that emerge if an emotion is very strong. These manifestations are entities which cast different spells on PCs in close proximity, depending on the emotions that the manifestations represent. PCs can also partake in authoring manifestations that become part of the world and the game-play in it. In the Pataphysic Institute potential story structures are governed by the relations the sentiment nodes constitute between entities.Because games set in persistent virtual game worlds (VGWs) have massive numbers of players, these games need methods of characterisation for playable characters (PCs) that differ from the methods used in traditional narrative media. VGWs have a number of particularly interesting qualities. Firstly, VGWs are places where players interact with and create elements carrying narrative potential. Secondly, players add goals, motives and driving forces to the narrative potential of a VGW, which sometimes originates from the ordinary world. Thirdly, the protagonists of the world are real people, and when acting in the world their characterisation is not carried out by an author, but expressed by players characterising their PCs. How they can express themselves in ways that characterise them depend on what they can do, and how they can do it, and this characterising action potential (CAP) is defined by the game design of particular VGWs. In this thesis, two main questions are explored. Firstly, how can CAP be designed to support players in expressing consistent  characters in VGWs? Secondly, how can VGWs support role-play in their rule-systems? By using iterative design, I explore the design space of CAP by building a semiautonomous agent structure, the Mind Module (MM) and apply it in five experimental prototypes where the design of CAP and other game features is derived from the MM. The term \textit{semiautonomy} is used because the agent structure is designed to be used by a PC, and is thus partly controlled by the system and partly by the player. The MM models a PC's personality as a collection of traits, maintains dynamic emotional state as a function of interactions with objects in the environment, and summarises a PC's current emotional state in terms of `mood'.   The MM consists of a spreading-activation network of affect nodes that are interconnected by weighted relationships.  There are four types of affect node: personality trait nodes, emotion nodes, mood nodes, and sentiment nodes. The values of the nodes defining the personality traits of characters govern an individual PC's state of mind through these weighted relationships, resulting in values characterising for a PC's personality. The sentiment nodes constitute emotionally valenced connections between entities. For example, a PC can `feel' anger toward another PC. This thesis also describes a guided paper-prototype play-test of  the VGW prototype World of Minds, in which the game mechanics build upon the MM's model of personality and emotion. In a case study of AI-based game design, lessons learned from the test are presented. The participants in the test were able to form and communicate mental models of the MM and game mechanics, validating the design and giving valuable feedback for further development. Despite the constrained scenarios presented to test players, they discovered interesting, alternative strategies, indicating that for game design the `mental physics' of the MM may open up new  possibilities.The results of the play-test influenced the further development of the MM as it was used in the digital VGW prototype the Pataphysic Institute. In the Pataphysic Institute the CAP of PCs is largely governed by their mood. Depending on which mood  PCs are in they can cast different `spells', which affect values such as mental energy, resistance and emotion in their targets. The mood also governs which `affective actions' they can perform toward other PCs and what affective actions they are receptive to. By performing affective actions on each other PCs can affect each others' emotions, which - if they are strong - may result in sentiments toward each other. PCs' personalities govern the individual fluctuations of mood and emotions, and define which types of spell PCs can cast. Formalised social relationships such as friendships affect CAP, giving players more energy, resistance, and other benefits. PCs' states of mind are reflected in the VGW in the form of physical manifestations that emerge if an emotion is very strong. These manifestations are entities which cast different spells on PCs in close proximity, depending on the emotions that the manifestations represent. PCs can also partake in authoring manifestations that become part of the world and the game-play in it. In the Pataphysic Institute potential story structures are governed by the relations the sentiment nodes constitute between entities.

No description available.

Vaccines famously possess positive externalities that make them susceptible to the collective action dilemma: when I get vaccinated, I protect not only myself, but also those who I might otherwise have infected. Thus, some people will have an incentive to free ride on the immunity of others. In a population of rational agents, the critical level of vaccination uptake required for herd immunity will therefore be difficult to attain in the long run, which poses difficulties for disease eradication. In this doctoral dissertation, I explore different implications of the collective action dilemma of vaccination, and different ways of ameliorating it. First: given that coercion or force could solve the dilemma, and democracies may be less likely to engage in policies that violate the physical integrity of citizens, democracies may also be at a disadvantage compared to non-democracies when securing herd immunity. In essay I, I show that this is, empirically, indeed the case. Barring the use of extensive coercion therefore necessitates other solutions. In essay II, I highlight the exception to individual rationality found in other-regarding motivations such as altruism. Our moral psychology has likely evolved to take other's welfare into account, but the extent of our prosocial motivations vary: a wider form of altruism that encompasses not just family or friends, but strangers, is likely to give way to a more narrow form when humans pair-bond and have children. This dynamic is shown to apply to the sentiments underlying vaccination behavior as well: appeals to the welfare of society of getting vaccinated have positive effects on vaccination propensity, but this effect disappears in people with families and children. On this demographic, appeals to the welfare of close loved ones instead appears to have large effects. In essay III, I investigate whether the prosocial motivations underlying vaccination behavior are liable to be affected by motivation crowding - that is, whether they are crowded out when introducing economic incentives to get vaccinated. I find that on average, economic incentives do not have adverse effects, but for a small minority of highly prosocially motivated people, they might.

Participants executed right-handed reach-to-grasp movements toward horizontally translating targets. Visual feedback of the target when reaching, as well as the presence of additional cues placed close (Experiment 1) or far (Experiment 2) above and below the target’s path was manipulated. Additional cue presence appeared to impair participants’ ability to extrapolate the disappeared target’s motion, and caused grasps for occluded targets to be less accurate. Final gaze and grasp positions were more accurate when reaching for leftward moving targets, suggesting individuals use different grasp strategies when reaching for targets travelling away from the reaching hand. Comparison of average fixations at reach onset and at the time of the grasp suggested that participants accurately extrapolated the occluded target’s motion prior to reach onset, but not after, resulting in inaccurate grasps. New information is provided about the eye-hand strategies used when reaching for moving targets in unpredictable visual conditions. / October 2016

The presence of human pharmaceuticals in the environment has raised concerns regarding their potential adverse effects on non-target aquatic organisms. Pharmaceuticals are designed to target specific molecular pathways in humans in order to produce known pharmacological and physiological responses, before toxicological effects are seen. The “Read-Across Hypothesis” stipulates that pharmaceuticals can produce similar biological effects in fish, as in humans, if the molecular target is conserved, and the internal (blood plasma) concentrations are similar. The read-across hypothesis was tested using ibuprofen, a non-steroidal anti-inflammatory drug, and the model fish test species, the fathead minnow (Pimephales promelas), to determine if ibuprofen can cause similar target-mediated effects in teleost fish and humans, at comparable blood plasma concentrations. Fathead minnows were exposed, using continuous flow-through systems, for ≤96 hours to a range of ibuprofen water concentrations (100, 270, 370 and 500 µg/L) to determine if plasma concentrations similar to human therapeutic plasma concentrations (HTPCs, or Cmax) could be established in fish blood plasma. The mode of action of ibuprofen was used to identify relevant endpoints (i.e. cyclooxygenase (COX) enzyme) in order to examine target-mediated effects following drug exposure. The water and plasma ibuprofen concentrations were determined using LC-MS/MS. The measured ibuprofen plasma concentrations in individual fish were linked to target-mediated effects on COX gene expression, COX enzyme activity and prostaglandin E2 (PGE2) synthesis (products of COX activity), which were quantified using molecular (QPCR) and biochemical (colourimetric and enzyme immunoassay) assays, and linked with the Cmax of ibuprofen. It was demonstrated that in fish with a mean ibuprofen plasma concentration 1.8-fold below the Cmax, PGE2 concentrations (the most robust endpoint) was significantly inhibited following ibuprofen exposure. However, in fish exposed to an ibuprofen concentration closer to (2 to 3-fold above) environmentally relevant water concentrations (i.e. 9 µg/L), when the mean plasma concentration was 224-fold below the Cmax, fish did not respond to ibuprofen exposure. This study provides qualitative and quantitative evidence for the applicability of the “read-across hypothesis”, and highlights its potential utility for prioritising pharmaceuticals for environmental risk assessment.

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

Cette thèse examine comment en l'espace de quelques années, des collectifs sont créés au Liban, en tant qu'«espaces de passage» politiques pour des acteurs à la recherche de ressources permettant une reconversion d'un capital militant engrangé. Ce qui nous a amené à un double questionnement: que nous dit ce «moment» de l'altermondialisme au Liban de l'altermondialisme en général? Et de l'espace du militantisme au Liban? Comment le label altermondialiste est revendiqué dans un contexte particulièrement verrouillé d'une part par le système politique dont les acteurs dominants disposent de ressources importantes pour entraver les mobilisations protestataires, d'autre part par un système partisan et associatif dont les militants altermondialistes s'évertuent de se distinguer. Nous avons aussi examiné les «bricolages singuliers» de cadres de références altermondialistes, pour proposer une «analyse localisée» de l'altermondialisme : si la mouvance s'inscrit dans un horizon idéologique et langagier «international», elle s'organise, se comprend, s'énonce, se transforme avant tout dans un système de contraintes mais aussi un «dialecte» tout libanais. Plutôt que de proposer une analyse en termes d'importation de la cause, nous nous sommes penchés sur l'idée d'une greffe de la cause à saisir dans les interactions possibles entre son énonciation locale et ses avatars globaux, mais aussi entre les innovations militantes que l'altermondialisme libanais comprend et les formes de reproductions locales qui le travaillent. Basant la démonstration sur quatre collectifs, cette thèse vise à apporter un éclairage sur les politiques protestataires au Liban en combinant, aux différentes étapes de l'enquête et de la démonstration, une approche mésosociologique (au niveau des collectifs) et microsociologique (au niveau des acteurs). Nous tenterons ainsi de comprendre comment et pourquoi le militantisme altermondialiste a constitué un militantisme de «passage» au Liban. / This thesis explores how in the space of few years, we have witnessed the formation of collectives in Lebanon as "political pathways" for actors searching for resources to allow the reconversion of accumulated militant capital, which raises a two-folded question: What does this moment of "alternative-globalization" tell us about alternative globalization in general? And what does it tell us about the militant and activist space in Lebanon? How was the label of "alternative-globalization" reclaimed facing a context which from the one hand, important and significant resources are being employed by the Lebanese political system, and its dominant actors to haIt and hinder mobilizations and protests, while on the other, facing a partisan and associative system, which the alternative globalization militants and activists are striving to distinguish themselves from it. Throughout this thesis, we will be examining particular and specific "bricolages" of the alternative globalization's frame of reference to be able to propose a "localized analysis" of alternative globalization: Although the alternative globalization movement is of an international ideological and linguistic frame and context, yet it is organized, understood and transformed within a local system of constraints, and then voiced in a Lebanese "dialect". lnstead of proposing an analysis of importing the cause, we are examining the idea of adapting and reclaiming the cause between the existing and possible interactions between local limitations and manifestations and its global actors (avatars), but also, between the Lebanese activist innovations of alternative globalization and its reproduced local forms. Basing our analysis on four collectives, this thesis aims to shed the light on protest politics adopted in Lebanon, while combining, at different stages of our study, the meso-sociological (on the level of the collectives) and the micro-sociological (on the level of actors). By doing so, we are trying to understand how and why the alternative globalization constituted an activist/militant space of passage for the movement in Lebanon.

Le mouvement accru de rationalisation des dépenses publiques conduit les acteurs publics français et notamment les collectivités territoriales à faire de nombreux choix et arbitrages parmi les initiatives menées en-dehors du champ traditionnel de leurs compétences obligatoires. « Que faire de l'Action Internationale ? » est au centre des débats, alors que la demande sociale est toujours plus conséquente sur les territoires français. Comment comprendre qu'en parallèle des efforts de plus en plus importants demandés aux citoyens, on dépense de l'argent public ailleurs? En période de crise, certaines politiques publiques sont remises en question et peuvent paraître superflues. Au premier regard, l'action internationale est de celles-ci. Ce travail vise à répondre à la question suivante : pourquoi les collectivités territoriales coopèrent-elles à l'échelle internationale ?Les actions internationales des collectivités territoriales relèvent historiquement d'une démarche de solidarité internationale. La perception de la coopération décentralisée comme outil d'aide au développement dans les pays partenaires est, encore aujourd'hui, une réalité constamment rappelée dans les discours des élus locaux, des associations partenaires, et de l'Etat. Aussi, la coopération décentralisée ne révolutionne-t-elle pas les objectifs généraux de l'Aide Publique au Développement, dans la mesure où elle constitue davantage un changement d'échelle qu'un changement de modèle. Pourtant, ces dernières années, apparaissent des visions plus « stratégiques » de l'AICT, qui a connu des évolutions en termes notamment de diversification géographiques et thématiques. On voit ainsi se développer de plus en plus d‘actions internationales à caractère économique ou visant le rayonnement des territoires et leurs positionnement sur la scène internationale.En 2013, l'Action Internationale des Collectivités Territoriales se situe donc, selon les contextes, quelque part entre l'aide et une véritable co-opération. La nécessaire synthèse entre les attentes émises par les collectivités territoriales étrangères et l'intérêt local pour les territoires français oblige alors à questionner les aspects fondamentaux que sont le partenariat et la marge de négociation des deux parties. La réciprocité peut-elle exister ? Est-il possible de penser l'Action internationale comme un outil de résolution des problématiques locales ? De quelle(s) manière les expériences des collectivités territoriales partenaires peuvent elles représenter des sources d'inspiration et d'innovation utiles au développement des territoires français ? Ces différentes questions nous amèneront à interroger la place de l'Action internationale au sein des politiques publiques locales : une compétence à part entière ou un mode d'exercice et d'amélioration des compétences « traditionnelles » ? / Increasing cuts of local expenses lead French public authorities make decisions and choices between public policies which do not look priority. In times of economic crisis, some policies may look useless and can be questioned. Should local governments maintain international action whereas social demand is deeply increasing on French territories? Is it still justifiable to keep on spending public money abroad?Local government's international actions (LGIA) are historically based on an international solidarity practice. Decentralized cooperation does not seem to really “revolutionize” Development Public Aid: the scale has changed, not the model. Nevertheless, these last years, LGIA knew real deep geographical and thematic evolutions. Strategic visions are emerging. Economic cooperation, international forecasts…local government's international action became a way for territories to position on international scene.In 2013, Local Government's International Action is located, depending on the contexts, somewhere between aid and real cooperation. Which synthesis can be made between foreign partners' wishes and local interest? Partnership and negotiations between the two parties are key-notions. How to evaluate relationships between territories? Does reciprocity really exists? Can LGIA be part of territorial projects and seen as a strategic way to work on French territorial stakes? How can local governments improve their own practices by inspiring from foreign experiences? Is LGIA a fully local public policy or a transversal operating mode?