Alteration of one sensory system can have striking effects on the processing and organization of the remaining senses, a phenomenon known as cross-modal plasticity. The goal of this thesis was to understand the circuit basis of this form of plasticity. I established the mouse as a model system for studying cross-modal plasticity by comparing population activity in visual cortex between animals reared in complete darkness from birth (DR) to those housed in a normal light/dark environment (LR). I found that secondary visual cortex (V2L) responds much more strongly to auditory stimuli in DR than LR. I provide evidence that there is a sensitive period for cross-modal responses that ends in early adulthood. I also show that exposure to light later in life reduces V2L auditory activity to LR levels. I recorded single units to show that there is a higher percentage of auditory responsive neurons in DR V2L. In collaboration with Lia Min in Michela Fagiolini’s laboratory, we discovered that this was associated with an increase in the number of projections from auditory thalamus and auditory cortex. We also provide evidence that V2L is multimodal from birth and becomes less so with visual experience. I examined several molecular pathways that are affected by dark-rearing to see if they are involved in cross-modal plasticity. I found that Nogo receptor (NgR), Lynx1, and Icam5 signaling all play a fundamental role in controlling the duration of plasticity. I also show that the hyperconnectivity in NgR -/- and DR mice leads to an increase in multisensory enhancement. In primary visual cortex, cross-modal influences were much weaker. Similar to V2L, the distribution of cell types was affected by NgR signaling. I also found that both the range of cross-modal influence and its sign (excitatory or inhibitory) is dependent on visual experience. Finally, I show that NgR signaling and the maturation of inhibitory circuits affect these two properties. Together, these results provide evidence of the molecular mechanisms underlying cross-modal plasticity. We believe that this will further our knowledge of how to improve rehabilitation strategies after loss of a sensory system.

This dissertation examines the role of modal verbs and rhetoric in the creation of Shakespeare's comic action. I argue that by focusing on the characters' uses of language in these plays, we can recover a sense of subjectivity and agency for Shakespeare's comic characters, instead of treating them as mere "types" swept along by the force of comic convention. Modal verbs--"can," "may," "must," "ought," and "will"--encode and enact subjectivity at the linguistic level, demonstrating a speaker's perceptions about the action of the main verb: whether a speaker thinks an action is possible or impossible, likely or unlikely, necessary or merely beneficial. Modal verbs therefore indicate an entirely different category of comic action: not just the oversized action of mistaken identity or farce, but the more subtle mental activity that underpins all subsequent action. Likewise, an examination of Shakespeare's comic rhetoric reveals that, far from being inconsequential or merely decorative, it is a force in its own right; I argue that the characters' insistence on the overt use of rhetorical devices, wordplay, and logical debate is a form of action that creates the comic world. Characters use strategies derived from logic and rhetoric in order to persuade themselves and others into positive action, achieving comic endings by verbal means.

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According to the United Nations’ report, State of World Population 2008, humankind has come to a turning point; more than 50% of the earth’s population now lives in urban centres. Along with considerations for housing, employment, and public health, this shift changes the way we design roads and streets; it escalates the number of automobiles in urban areas with finite room for road expansion. Space constraints, along with intense development of alternative transportation fuels, and the burden of sprawling suburbs on municipal infrastructures suggest the hypothesis that before we run out of energy alternatives for personal mechanized transport, we will run out of space in which to use it. This thesis explores how Toronto, a city largely designed for automobile use, is being re-adapted into a city wherein public and active transportation can once again be the primary means of urban mobility and the opportunities inherent in the development of interregional multi-modal transit stations for the cultivation of civic space, local commerce, urban form, and commercial transportation.

This dissertation deals with semantics of modality in general and semantics of the Norwegian modal verbs in particular. My lead-off assumption is that modality deals with people’s attitude towards the trustworthiness of propositions (epistemic attitude) and the presence or absence of obstacles for a state of affairs to occur (non-epistemic attitude). I distinguish between neutral and non-neutral attitude on the one hand and between simple and complex attitude on the other. Neutral attitude means that, in the speaker’s view (or someone else’s view, if the speaker is reporting others’ attitude), there are no obstacles to accept a proposition as correct or a state of affairs as likely to occur. However, the speaker may equally accept that the same proposition may turn out to be incorrect, or the same state of affairs may turn out not to be worth to occur. In either case, no conflict will arise between the speaker’s beliefs (expectations) and the reality. Non-neutral attitude means that the speaker only is willing to accept a proposition as correct, or a state of affairs as likely to occur. If the proposition turns out to be incorrect, or the state of affairs turns out not to be likely to occur, a conflict arises between the speaker’s beliefs (expectations) and reality. At the same time, the speaker may signal that other participants may have different attitudes than her own, which does not mean that the speaker is unsure about her own attitude. I use the terms simple and... [to full text] / Šioje disertacijoje tyrinėjama modalumo semantika, ypatingą dėmesį skiriant norvegų kalbos modaliniams veiksmažodžiams. Modalumas suvokiamas kaip kategorija, susijusi su žmonių požiūriu į propozicijų tikėtinumą (episteminis požiūris) ir į kliūčių įvykiams įvykti ar situacijoms susiklostyti buvimą ar nebuvimą (neepisteminis požiūris). Išskiriami, viena vertus, neutralus ir neneutralus požiūris, ir, kita vertus, paprastas ir kompleksinis požiūris. Terminas paprastas požiūris vartojamas kalbant apie atvejus, kai kalbėtojas posakyje tik išreiškia vieną požiūrį, nesudarymas prielaidų manyti, kad egzistuoja ir kitokių požiūrių galimybė. Terminas kompleksinis požiūris vartojamas kalbant apie atvejus, kai kalbėtojas, išreikšdamas vieną požiūrį, sykiu leidžia manyti, kad galima turėti ir kitokį, alternatyvų požiūrį. Neutralus požiūris visada būna paprastas, o neneutralus gali būti arba paprastas, arba kompleksinis. Toliau disertacijoje šis modelis pritaikomas norvegų kalbos modalinius veiksmažodžių KUNNE, MÅTTE, SKULLE, VILLE ir BURDE semantiniam aprašui. Esamojo laiko forma kan dažniausiai vartojama neutraliam požiūriui išreikšti, o esamojo laiko formos må, skal ir vil dažniausiai vartojamos paprastam neneutraliam požiūriui išreikšti. Ir esamojo laiko forma bør, ir būtojo laiko (preterito) forma burde dažniausiai vartojamos kompleksiniam neneutraliam požiūriui reikšti. Būtojo laiko formos skulle ir ville gali būti pavartojamos ne temporaline reikšme, transformuojant paprastą... [toliau žr. visą tekstą]

Šioje disertacijoje tyrinėjama modalumo semantika, ypatingą dėmesį skiriant norvegų kalbos modaliniams veiksmažodžiams. Modalumas suvokiamas kaip kategorija, susijusi su požiūriu į propozicijų tikėtinumą (episteminis požiūris) ir kliūčių buvimą ar nebuvimą įvykiams įvykti ar situacijoms susiklostyti (neepisteminis požiūris). Išskiriami, viena vertus, neutralus ir neneutralus požiūris, ir, kita vertus, paprastas ir kompleksinis požiūris. Terminas paprastas požiūris vartojamas kalbant apie atvejus, kai kalbėtojas posakyje tik išreiškia vieną požiūrį, nesudarymas prielaidų manyti, kad egzistuoja ir kitokių požiūrių galimybė. Terminas kompleksinis požiūris vartojamas kalbant apie atvejus, kai kalbėtojas, išreikšdamas vieną požiūrį, sykiu leidžia manyti, kad galima turėti ir kitokį, alternatyvų požiūrį. Neutralus požiūris visada būna paprastas, o neneutralus požiūris gali būti arba paprastas, arba kompleksinis. Toliau disertacijoje šis modelis pritaikomas norvegų kalbos modalinių veiksmažodžių KUNNE, MÅTTE, SKULLE, VILLE ir BURDE semantiniam aprašui. Esamojo laiko forma kan dažniausiai vartojama neutraliam požiūriui išreikšti, o esamojo laiko formos må, skal ir vil dažniausiai vartojamos paprastam neneutraliam požiūriui išreikšti. Ir esamojo laiko forma bør, ir būtojo laiko (preterito) forma burde dažniausiai vartojamos kompleksiniam neneutraliam požiūriui reikšti. Būtojo laiko formos skulle ir ville gali būti pavartojamos ne temporaline reikšme, transformuojant paprastą... [toliau žr. visą tekstą] / This dissertation deals with semantics of modality in general and semantics of the Norwegian modal verbs in particular. My starting point is the assumption that modality deals with people’s attitude towards the trustworthiness of propositions (epistemic attitude) and the presence or absence of obstacles for states of affairs to occur (non-epistemic attitude). I distinguish between neutral and non-neutral attitude on the one hand and between simple and complex attitude on the other. The terms simple and complex attitude are used to distinguish between cases where the speaker in her utterance expresses only one attitude without admitting any alternative attitudes (simple), and cases where she expresses one attitude at the same time as she signals in the same utterance that other participants may have a different attitude towards the status of the target of attitude (complex). Neutral attitude is always simple, while non-neutral attitude may be either simple or complex. Then I apply this model on the Norwegian modal verbs KUNNE, MÅTTE, SKULLE, VILLE and BURDE. I argue that the present tense form kan typically expresses neutral attitude, while the present tense forms må, skal and vil typically express non-neutral simple attitude. Both the present tense form bør and the preterite form burde typically express non-neutral complex attitude. The preterite forms skulle and ville may be used with non-temporal meaning, to transform a non-neutral simple attitude into complex attitude.

The availability and use of new materials and construction techniques are allowing bridges to be built that are longer and more slender to those that have been constructed in the past. This can cause bridges to have lower stiffness and damping, and thus be less able to resist dynamic effects. This is of special concern for pedestrian bridges, because the harmonic loads that pedestrians apply to the bridge have the potential to excite the bridge’s natural frequencies. In addition, pedestrians can be sensitive to these vibrations. A model was developed in order to better understand the effects that a pedestrian can have on these vibration-prone bridges. The model consisted of two parts: a finite element model that used the structural data for the bridge in order to produce mass-normalized mode shapes, and a bridge-pedestrian interaction program that used the structural and modal data, along with pedestrian loading scenarios, to generate the bridge response. A parametric study of two bridges was conducted. The bridges included: a short span bridge that would not be expected to respond excessively to pedestrian loads, and a long-span, lively bridge that had natural frequencies in the range of pedestrian loading. Many loading cases were examined by varying the following parameters: load case, number of pedestrians, damping, and pacing frequency. The modal solution was an effective method of finding the bridge responses. It was determined that pedestrian loads can be represented by a simple constant plus sinusoidal load. The excessive vibrations of long and slender bridges could be addressed by increasing damping on susceptible modes. / Thesis (Master, Civil Engineering) -- Queen's University, 2010-05-03 12:36:05.561

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Ultra-lightweight thermoformed stiffened structures are emerging as a viable option for spacecraft applications due to their advantage over inflatable structures. Although pressurization may be used for deployment, constant pressure is not required to maintain stiffness. However, thermoformed stiffening features are often locally nonlinear in their behavior under loading. This thesis has three aspects: 1) to understand stiffness properties of a thermoformed stiffened ultra-lightweight panel, 2) to develop finite element models using a phased-verification approach and 3) to verify panel response to dynamic loading. This thesis demonstrates that conventional static and dynamic testing principles can be applied to test ultra-lightweight thermoformed stiffened structures. Another contribution of this thesis is by evaluating the stiffness properties of different stiffener configurations. Finally, the procedure used in this thesis could be adapted in the study of similar ultra-lightweight thermoformed stiffened spacecraft structures.

Résumé : Le recalage automatique des images issues de la tomographie par émission de positrons (TEP) et de l’imagerie par résonance magnétique (IRM) du petit animal pose un problème difficile à résoudre, tant sur l’aspect de la précision, du taux de réussite et de convergence que sur la rapidité d’exécution. En fait, la plupart des techniques de recalage actuelles sont développées et appliquées aux cerveaux humains, mais ne sont pas aussi efficaces lorsqu’appliquées sur des données animales. L’anisotropie impor¬tante des voxels (résolution fine dans le plan de l’acquisition, mais grande épaisseur de coupe) et la dégradation des images associée à ce type d’acquisition s’additionne au manque d’information d’intensité et de complexité anatomique de ce type de jeu de données. Ce mémoire met l’accent sur les techniques multimodales de recalage automatique et de leurs limites, appliquées particulièrement à la TEP et l’IRM du petit animal. Dans l’article principal présenté dans ce mémoire, nous proposons une mesure qui utilise un recalage multirésolution en parallèle (imbriqué dans la fonction d’énergie) au lieu d’une approche classique de multirésolution séquentielle, influen¬çant directement la procédure du recalage. En combinant les niveaux de basse et haute résolution des images, nous nous assurons une plus grande insensibilité par rapport au bruit, d’une ouverture accrue permettant une meilleure convergence et rapidité d’exécution. L’article démontre que notre nouvelle approche automatique est un algorithme de recalage robuste et efficace avec un taux de réussite élevé. Nous présentons également dans ce mémoire certains détails d’implantation de l’outil, qui a été créé par l’auteur de ce document, reposant sur le recalage classique et la nouvelle méthode décrite dans ce mémoire.||Abstract: Automatic registration of small animal Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI) data represents a difficult problem in terms of convergence speed, accuracy and success rate. In fact, most existing registration methods are developed and applied to human brain volumes but these are not as effective for small animal data because of the lack of intensity information in the images and often the large anisotropy in voxel dimensions (very small in-plane resolution and large slice thickness). This master thesis focuses on multi-modal automatic registration techniques and their limitations, especially applied to PET-MRI registration. In the main article of this master thesis, we propose a new registration measure that combines multi-resolution in parallel (in the same energy function) instead of a classic sequential multi-resolution, which influence the procedure of the registration as well. By combining low and high resolution levels of images, we can gain from the low noise sensitivity and aperture at coarse levels and higher contrast and details at higher levels, which helps convergence accuracy and speed. The paper shows that our new approach is therefore an automatic, robust and efficient registration algorithm with a high success rate. We also present in this document some implementation details on the tool which was created by the author of this thesis based on the classic registration and the new approach described in this thesis.