VictorJuiz/thesis huggingface dataset:
A Quest for High-performance Peer-to-peer Live Multimedia Streaming

Demands for multimedia content, one form of digital content, are continuously increasing at a phenomenal pace, as video features are commonly available on personal devices, such as iPod, cell phone, laptop, PDA, and Blackberry. The streaming service poses unique bandwidth and delay challenges to application designers. The size of a typical video content is usually orders of magnitude larger than that of any other type of content, resulting in high demands for bandwidth contribution from the content providers. Even more challenging, the content must be delivered to end hosts in real time to maintain smooth playback, i.e., the content must be transmitted at a satisfactory rate. In this thesis, we present our research towards a high-quality peer-to-peer live streaming system that utilizes network coding, a novel technique that permits coding at every peer, which has proven benefits in file dissemination applications. To ensure the practicality of our work, it is our imperative objective to conduct all experiments under realistic settings.

Keywords: Peer-to-Peer multimedia streaming
Network Coding
Advisor: Li, Baochun
Malta, Motherhood, and Infant Mortality: Integrating Biological and Sociocultural Insights

Because infants are the most vulnerable members of a community, their deaths – and the resulting infant mortality rate (IMR) – are said to signal more fundamental problems that are likely to affect the general health of a community. However, a focus on proximate- and intermediate-level risk factors in epidemiological analyses presents a decontextualized picture and ignores the role of larger forces on health, disease, and illness. In response to this trend, this project will contribute to a revitalization of the use of infant mortality as an index of larger social problems by tempering statistical analyses with critical reflection regarding the effects of the liminal position of Malta within the British imperial system, prior to the Second World War. In addition, by bringing together several analytic approaches which often proceed in parallel, rather than in dialogue – historical epidemiology, social history, and the analysis of colonial discourse – this dissertation highlights the problematics of knowledge production at both the theoretical and methodological level. As a result, my work is not just about Malta, one moment in history, the calculation of infant mortality rates, or the disentanglement of various determinants of infant mortality in this context; it is about the dynamics and repercussions of power differentials and of social, economic, and political inequalities, as they define and structure health outcomes and experiences. Specifically, I will show that fluctuations in international tensions affected Malta’s population on a number of levels because of the island’s importance as a British military and naval base and its location in the middle of the Mediterranean. I will demonstrate how Malta’s “strategic position” restricted political and economic development in the island and articulated with colonial perceptions of the Maltese as “Other” and Malta as “overpopulated.” Finally, I will argue that international tensions, Malta’s location within Empire, and perceptions of the island and its inhabitants in the early twentieth century affected the ways in which infant deaths were explained and understood and the strategies of intervention initiated in the island to curtail infant mortality – all of which had a tremendous impact on the rates at which infants in Malta died.

Keywords: Infant mortality rate
Malta
Mothering
Historical demography
Colonial Discourse Analysis
Overpopulation
Social history
Critical Medical Anthropology
Advisor: Sawchuk, Lawrence A.
Knowledge-based Vertical Integration: The Nature of Knowledge and Economic Firm Boundary Location

This research extends the knowledge-based view of the firm as it relates to organizational structure. In particular, this research provides evidence that fundamental classifications of knowledge are measurable, in relative terms, as factors of production. It then relates differences in relative quantities of these classifications of knowledge to the presence or absence of inter-firm boundaries. Finally, this study provides evidence that financial performance may be related to the alignment of organizational structure with knowledge-based factors of production. This study contributes to strategic management theory by offering a potential solution to the difficulties of measuring knowledge as a factor of production. The research was motivated by the belief that it is the cost and value of knowledge that determines economic efficiency (Simon, 1999). By surveying professionals in the mutual fund industry for their relative reliance on three classifications of knowledge, this study suggests a set of measures of knowledge-based factors of production. These measures in turn support the testing of hypotheses related to the vertical integration (or de-integration) of adjacent stages of production. Researchers have typically categorized organizational knowledge as either tacit or explicit. This research develops the concept of encapsulated knowledge as a fundamental classification of knowledge. Encapsulated knowledge is neither tacit nor explicit, because it is externalized and implicit. Progress in measuring knowledge is made by distinguishing between knowledge that resides in human minds (tacit), knowledge that is codified as information (codified), and knowledge that is embodied in the design and functionality of physical artefacts (encapsulated). Relative reliance on the fundamentally different knowledge-based factors of production was found to vary between adjacent stages of production, despite the essential overlap of jointly held substantive knowledge. Portfolio managers are generally less (more) reliant on tacit (encapsulated) knowledge than other investment management professionals in the mutual fund complex. In addition, portfolio managers whose firms are de-integrated from the mutual fund management firms were found to be more (less) reliant on tacit (encapsulated) knowledge than their integrated counterparts. Finally, alignment between mutual fund structure and reliance on knowledge-based factors of production was found to affect performance of mutual funds.

Keywords: Strategic Management
Knowledge-Based View of the Firm
Organizational Structure
Mutual Funds
Advisor: Choo, Chun Wei
Silverman, Brian S.
Biomimetic Aminoacylation

Abstract “Biomimetic Aminoacylation” Svetlana K. Tzvetkova Doctor of Philosophy, 2008 Graduate Department of Chemistry University of Toronto The accuracy of ribosomal protein synthesis depends on the fidelity of highly specific enzymes, aminoacyl tRNA synthetases, towards amino acid – tRNA pairs. These biological catalysts are responsible for activating the amino acids as aminoacyl adenylates and for their subsequent attachment to the 2’- or 3’-OH at the 3’-terminal of the correct tRNA to give aminoacyl-tRNA. Extended diversity in protein structure and function could be achieved if non-natural side chains can be introduced in protein synthesis. This requires that the acceptor stem of a tRNA molecule be synthetically aminoacylated. The most widely used methods for charging tRNA with non-natural amino acids involve multi-step synthesis of an aminoacyl-pCpA and its consequent enzymatic ligation to truncated tRNA. No direct route to these species has been reported. We have developed a method for direct biomimetic aminoacylation of the 3’-terminal hydroxyls of tRNA. Our approach shows to be promising in reactions leading to direct 2’- or 3’-O-aminoacylation of not only nucleosides and nucleotides but also RNA in general and tRNA in particular. The system we have developed provides: 1) efficient activation of the amino acids as aminoacyl phosphates, analogues of the enzymatic intermediates, and 2) specific recognition of the 3’-terminal of tRNA by lanthanide ions present in the reaction. The aminoacylating reagents used in our studies were carefully selected to provide handles to follow the reaction: UV absorbance, fluorescence spectroscopy and 19F NMR. Lanthanide (III) ions can play a role similar to a key part of the aminoacyl tRNA synthetases – they bring the aminoacyl close to the 3’-terminal of tRNA, in this case by forming a bis-bidentate complex with the aminoacyl phosphate and the 2’,3’-diol functionality of the 3’-terminal adenosine. This process relies on the specificity towards the unique 3’-terminal diol on tRNA, provided by the metal ion and the simultaneous complexation of the aminoacyl phosphate.

Keywords: Aminoacylation tRNA
non-natural amino acids
Advisor: Kluger, Ronald
Investigating the Impact of Diffuse Axonal Injury on Working Memory Performance following Traumatic Brain Injury Using Functional and Diffusion Neuroimaging Methods

Traumatic brain injury (TBI) is a leading cause of disability globally. Cognitive deficits represent the primary source of on-going disability in this population, yet the mechanisms of these deficits remain poorly understood. Here functional and diffusion-weighted imaging techniques were employed to characterize the mechanisms of neurofunctional change following TBI and their relationship to cognitive function. TBI subjects who had sustained moderate to severe brain injury, demonstrated good functional and neuropsychological recovery, and screened positive for diffuse axonal injury but negative for focal brain lesions were recruited for the project. TBI subjects and matched controls underwent structural, diffusion-weighted and functional MRI. The functional scanning paradigm consisted of a complex working memory task with both load and executive control manipulations. Study one demonstrated augmented functional engagement for TBI subjects relative to healthy controls associated with executive control processing but not maintenance operations within working memory. In study two, multivariate neuroimaging analyses demonstrated that activity within a network of bilateral prefrontal cortex (PFC) and posterior parietal regions was compensatory for task performance in the TBI sample. Functional connectivity analyses revealed that a common network of bilateral PFC regions was active in both groups during working memory performance, although this activity was behaviourally relevant at lower levels of task demand in TBI subjects relative to healthy controls. In study three, diffusion-imaging was used to characterize the impact of diffuse white matter pathology on these neurofunctional changes. Unexpectedly, decreased white matter integrity was not correlated with working memory performance following TBI. However, markers of white matter pathology did inversely correlate with the compensatory functional changes observed previously. These results implicate diffuse white matter pathology as a primary mechanism of functional brain change following TBI. Moreover, reactive neurofunctional changes appear to mediate the impact of diffuse injury following brain trauma, suggesting new avenues for neurorehabilitation in this population.

Keywords: fMRI
TBI
Working Memory
Frontal Lobe
Advisor: Levine, Brian
Development, Evaluation and Application of a Pediatric Ulcerative Colitis Index (PUCAI)

This thesis uses the methods of sychometrics and clinimetrics to develop and evaluate a Pediatric Ulcerative Colitis Activity Index (PUCAI). The initial phases of item generation and reduction were performed previously. This thesis comprises five main studies. Study one: the weighting and formatting of an initial draft PUCAI using a cohort of 157 children with ulcerative colitis, enrolled prospectively in five pediatric IBD centers. Study two: the validation of the final draft on a separate prospective cohort of 48 children undergoing complete colonoscopy. The PUCAI was highly correlated with physician global assessment (PGA) (r=0.91), Mayo score (r=0.95) and colonoscopic appearance (r=0.77). The PUCAI was able to differentiate the different categories of disease activity, and cutoff points were defined. Study three: Assessment of the responsiveness of the PUCAI. The index demonstrated excellent responsiveness on 75 children seen twice during the study period (effect size=1.9, standardized response mean=2.2, responsiveness statistics=2.6, correlation with PGA of change=0.84, and area under the ROC curve=0.97 95%CI 0.93- 0.99). Study four was aimed at evaluating the predictive validity of the PUCAI, on a retrospective cohort of 99 children with severe ulcerative colitis admitted for intravenous corticosteroid therapy. The PUCAI, calculated on the third and fifth day of therapy was highly predictive of therapy failure at discharge and one year post discharge (area under the ROC curve 0.84 (95%CI 0.76-0.92). Study five: a methodological study evaluating the preferred way to determine the minimal clinically important difference (MCID) of health-related outcome measures. This study was conducted using the PUCAI and three other well established instruments. It was concluded that the MCID should be determined primarily by the anchor-based approach using the ROC curve method on the entire cohort, supplemented by calculating the minimal detectable difference beyond statistical error using the standard error of measurement. Small, moderate and large MCID values could be presented based on the degree of expected relevant change. Together, these studies have contributed to the rigorous development and thorough evaluation of a novel, non-invasive tool for assessing disease activity in pediatric ulcerative colitis clinical studies and practice.

Keywords: PUCAI
Validity
Responsiveness
Minimal important difference
Reliability
Ulcerative colitis
Pediatric
Acitivity index
Outcome measure
Advisor: Steinhart, A. Hillary
Physiology of Potassium Nutrition in Cereals: Fluxes, Compartmentation, and Ionic Interactions

Potassium (K+) is an essential nutrient and the most abundant cation in plant cells. Plants possess two transport systems for K+ acquisition: a high-affinity system (HATS), operating at external K+ concentrations ([K+]ext) below 1 mM, and showing reduced transport activity in the presence of ammonium (NH4+); and, a low-affinity system (LATS), operating at [K+]ext above 1 mM, that is not affected by NH4+. K+ transport and compartmentation were investigated in barley (Hordeum vulgare L.) and rice (Oryza sativa L.) using the non-invasive technique of compartmental analysis by tracer efflux (CATE), to simultaneously determine unidirectional membrane fluxes, ion concentrations, and exchange characteristics in subcellular compartments. These studies revealed striking differences in unidirectional K+ fluxes between HATS and LATS. It was found that flux measurements, using traditional direct influx (DI) protocols, accurately represented HATS influx, but underestimated LATS influx by as much as seven-fold. In both barley and rice, LATS K+ fluxes were found to undergo rapid, futile cycling, with the ratio of efflux:influx 3 to 5 times greater, and the cytosolic exchange rate 2 to 3 times faster than under HATS. Based upon plasma-membrane electrical potential measurements, efflux was found to be active under LATS conditions. LATS-mediated conditions for K+ were found to provide relief from NH4+ toxicity in barley by immediately reducing NH4+ influx by more than 50%, and significantly reducing NH4+ futile cycling. Employing the K+ channel inhibitors cesium, lanthanum, and tetraethylammonium, NH4+ was shown to have both K+-sensitive and –insensitive influx pathways at high [NH4+]ext. Based on current models of flux energetics, the combined uptake of K+ and NH4+ was found to utilize 60% of root oxygen consumption. Barley and rice both showed signs of NH4+ toxicity at low [K+]ext, but rice recovered at much lower [K+]ext, suggesting a crucial role of K+ in the NH4+-tolerance of rice. These experiments address fundamental aspects of K+ fluxes, and help provide a physiological framework for future studies of K+ transport and mineral nutrition.

Keywords: Potassium
Compartmental analysis
Nitrogen
Plant physiology
Efflux
Influx
Electrophysiology
Barley
Rice
Ammonium
Nitrate
Cellular Ion Exchange
Low-affinity transport system
High-affinity transport system
Advisor: Kronzucker, Herbert
Essays on Money, Banking and Payments

The history of money has always been intertwined with the history of banking. Nevertheless, very few papers have studied banking in a rigorous monetary environment. This thesis demonstrates that it is crucial to integrate these two literatures. I present three theories of money and banking, each generating results that are drastically different from those of the traditional banking models without microfoundations for money. Chapter 1 addresses the problem of monitoring the monitor in a model with private information and aggregate uncertainty. There is no need to monitor a bank if it requires loans to be repaid partly with money. A market arises at the repayment stage and generates information-revealing prices that perfectly discipline the bank. The mechanism also applies when multiple banks exist. With multiple banks, a prohibition on private money issuing not only eliminates welfare-improving money competition but also triggers free-rider problems among banks. In Chapter 2, I develop a dynamic model to address the following question: when both individuals and banks have private information, what is the optimal way to settle debts? I establish two main results: first, markets can improve upon the optimal dynamic contract in the presence of private information. Prices fully reveal the aggregate states and help solve the incentive problem of the bank. Secondly, it is optimal for the bank to require loans to be settled with short-term inside money, i.e., bank money that expires immediately after debt settlement. Short-term inside money makes it less costly to induce truthful revelation and achieves more efficient risk sharing. Chapter 3 studies bank runs in a model with coexistence of fiat money and private money. When fiat money is the only medium of exchange, a bank run equilibrium coexists with an equilibrium that achieves optimal risk sharing. In contrast, when private money is also a medium of exchange, there exists a unique equilibrium where no one demands early withdrawals of fiat money and agents in need of liquidity only use private money to finance consumption. This unique equilibrium achieves the first-best outcome and eliminates bank runs without having to resort to any government intervention.

Keywords: money
banking
payments
Advisor: Shi, Shouyong
Occupation Attributes Relate to Origin and Extent of Atrophy in Frontotemporal Lobar Degeneration

Occupation provides valuable information on premorbid ability in dementia. Not only is occupation related to cognitive and brain reserve, but premorbid sub-symptomatic impairment may influence prospective career choice. Frontotemporal lobar degeneration (FTLD) patients with professions dependent upon one hemisphere have demonstrated contralateral degeneration. The present work was the first group study to examine the relationship between atrophy in FTLD and occupation. Chapter one reviews methods for quantifying occupations and introduces the Occupational Information Network database. This database provided quantified occupation attribute data and enabled subsequent multivariate analyses. A principal component analysis yielded five factors that parsimoniously summarized verbal, physical, mechanical, mathematical and visuospatial occupational demands, some with hypothesized neuroanatomical substrates. Chapters two and three tested the hypothesis that occupation characteristics systematically relate to origin of atrophy in FTLD. In a multi-centre chart review of 588 patients, occupation information was related to location of atrophy. Patients with unilateral right atrophy had higher verbal scores than patients with unilateral left or bilateral atrophy. Thus, occupation selection occurring in early adulthood is related to lateralized brain damage in patients who develop FTLD decades later. The finding suggests that verbal occupations may have been pursued due to incipient right-hemisphere functional impairment. Alternatively, long-term engagement of verbal processes contributed to left-hemisphere reserve, right-hemisphere dysfunction, or both. In a subgroup of well-characterized patients with quantified brain imaging data, chapter three replicated and extended these findings. The lateralization effect was limited to the temporal lobes and included both verbal and mathematical ability. This pattern may reflect shared attributes between mathematics and language processing, which are mediated by left-temporal lobe structures. Patients whose professions placed high demands on language had relatively preserved left temporal lobes and atrophy originating in the right temporal lobes at disease onset whereas patients with less challenging linguistic occupations were more susceptible to the onset of atrophy in the left-temporal lobe. In chapter four, the hypothesized relationship between occupational attainment and global degeneration was supported. Patients with highly skilled occupations had less atrophy than patients with lower-skilled occupations. Notably, specific occupational attributes were predictive of brain volume after controlling for demography and disease progression. Overall, a relationship between occupation and FTLD is supported.

Keywords: Dementia
Occupation
Advisor: Levine, Brian
Spatially Explicit Simulation of Peatland Hydrology and Carbon Dioxide Exchange

In this research, a recent version of the Boreal Ecosystem Productivity Simulator (BEPS), called BEPS-TerrainLab, was adapted to northern peatlands and evaluated using observations made at the Mer Bleue bog located near Ottawa, Ontario, and the Sandhill fen located near Prince Albert, Saskatchewan. The code was extended and modified with a major focus on the adequate representation of northern peatlands' multi-layer canopy and the associated processes related to energy, water vapour and carbon dioxide fluxes through remotely-sensed leaf area index (LAI) maps. An important prerequisite for the successful mapping of LAI based on remote sensing imagery is the accurate measurement of LAI in the field with a standard technique such as the LAI-2000 plant canopy analyzer. As part of this research, a quick and reliable method to determine shrub LAI with the LAI-2000 instrument was developed. This method was used to collect a large number of LAI data at the Mer Bleue bog for the development of a new remote sensing-based methodology using multiple endmember spectral unmixing that allows for separate tree and shrub LAI mapping in ombrotrophic peatlands. A slight modification of this methodology allows for its application to minerotrophic peatlands and their surrounding landscapes. These LAI maps were used to explicitly represent the tree and shrub layers of the Mer Bleue bog and the tree and shrub/sedge layers of the Sandill fen within BEPS-TerrainLab. The adapted version of BEPS-TerrainLab was used to investigate the in fluence of mescoscale topography (Mer Bleue bog) and macro- and mesoscale topography (Sandhill fen) on wetness, evapotranspiration, and gross primary productivity during the snow-free period of 2004. This research suggests that future peatland ecosystem modelling efforts at regional and continental scales should include a peatland type-specific differentiation of macro- and mesoscale topographic effects on hydrology, to allow for a more realistic simulation of peatlands' soil water balance. This is an important prerequisite for the reduction of currently existing uncertainties in wetlands' contribution to North America's carbon dioxide and methane annual fluxes from an ecosystem modelling perspective.

Keywords: spatially explicit, process-oriented ecosystem modelling
biophysical parameter mapping
Advisor: Chen, Jing Ming