VictorJuiz/thesis huggingface dataset:
If you Want to be Slow you have to be Fast: Control of Slow Population Activities by Fast-spiking Interneurons via Network Multistability
Keywords: Hippocampus test
Slow population activities
Mathematical modelling

Slow population activities (SPAs) are population activities in the brain with frequencies of less than 5 Hz. SPAs are prominent in many brain structures including the neocortex and the hippocampus. Examples of SPAs include the neocortical EEG δ waves and the hippocampal large amplitude irregular activities during NREM sleep. These in vivo SPAs are believed to play a fundamental role in brain plasticity. However, despite many experimental attempts to understand SPAs, their mechanisms are still not well understood. It is unclear how the individual neurons can sustain low frequency activities on the network as a whole. In this thesis, we demonstrate that a mathematical and computational perspective is indispensable in understanding slow population phenomena and generating testable hypotheses for future experiments. Our focus is on a hippocampal slice preparation exhibiting spontaneous, inhibitory-based SPAs (hippocampal SPAs). We develop a multi-pronged approach consisting of parameter extraction, simulation, and mathematical analysis to elucidate the mechanisms responsible for hippocampal SPAs. Our results suggest that hippocampal SPAs are an emergent phenomenon. In other words, the network “slowness” is not directly represented by any particular individual element within the network. Instead, the low frequency activities on the network are the result of interactions between synaptic and intrinsic characteristics of individual inhibitory interneurons. Our simulations quantify these characteristics which underlie hippocampal SPAs. Specifically, our simulations predict that individual interneurons should 1) be moderately fast-spiking above threshold before the increase in spike frequency slows down with increasing drive, and 2) be well connected with one another for SPAs to occur. We also predict that excitatory noise levels have a larger influence on hippocampal SPAs than mean excitatory drive. Subsequent mathematical analyses show that the synaptic and intrinsic conditions of individual interneurons as predicted by simulations promote network multi-stability. Hippocampal SPAs occur when the network switches from one network firing state to another. Since many of the parameters we use for simulations are extracted from experiments, our simulation model is likely a reasonable representation of actual biological mechanisms in hippocampal networks.
Approaching the Examiner's Chair: Chronicling the Experiences of Piano Examiner Apprentices for the Royal Conservatory of Music
Keywords: music examiners
piano
piano pedagogy
Royal Conservatory of Music
music examinations
RCM exams
assessments
evaluations
music assessors
music evaluators
conservatories
examining boards
examiner training
music students
confidence level
comfort level
narrative inquiry

Examinations administered by the Royal Conservatory of Music (RCM) play a major role in the musical education of many individuals across Canada. The evaluative process needs to be a constructive one in order to ensure its positive impact on students’ musical education. Examiners who are confident and comfortable in their roles as assessors are more likely to provide this ideal environment for the students. Individuals at the dawn of their examining careers are prone to lower confidence and comfort levels due to their inexperience. Yet all music students deserve an optimal examination situation, even from new examiners. Ensuring that an examiner receives proper training will help to increase their confidence and comfort levels while assessing students. This study examined the elements of an examiner’s education, experience and preparation which contributed to higher confidence and comfort levels as they participated in the RCM evaluative process. Ten individuals participated in surveys and interviews. Seven were recent apprentices of the examiner training program and three were senior examiners. Their experiences and insights given in a narrative form shed light on which elements of their background and training benefited them as examiners. According to the participants, varied and extensive pedagogical training, taking exams as students and intensive performance education gave them the most advantages during their early careers as examiners. Regarding the examiner apprenticeship program, participants felt that they would have benefited from more practical experience during the early classroom seminar, additional opportunities to observe students at varying performing levels and more time for discussion with their mentors. These recommendations for background preparation and enhanced training are intended to give examiners greater confidence in their evaluative roles early in their careers, enabling them to provide constructive and effective assessments for students and their teachers.
Optimal Pricing and Capacity Planning in Operations Management
Keywords: Pricing
Capacity Planning
Location
Equilibrium

Pricing and capacity allocation are two important decisions that a service provider needs to make to maximize service quality and profit. This thesis attempts to address the pricing and capacity planning problems in operations management from the following three aspects. We first study a capacity planning and short-term demand management problem faced by firms with industrial customers that are insensitive to price incentives when placing orders. Industrial customers usually have downstream commitments that make it too costly to instantaneously adjust their schedule in response to price changes. Rather, they can only react to prices set at some earlier time. We propose a hierarchical planning model where price decisions and capacity allocation decisions must be made at different points of times. Customers first sign a service contract specifying how capacity at different times will be priced. Then, when placing an order, they choose the service time that best meets their needs. We study how to price the capacity so that the customers behave in a way that is consistent with a targeted demand profile at the order period. We further study how to optimally allocate capacity. Our numerical computations show that the model improves the operational revenue substantially. Second, we explore how a profit maximizing firm is to locate a single facility on a general network, to set its capacity and to decide the price to charge for service. Stochastic demand is generated from nodes of the network. Customers demand is sensitive to both the price and the time they expect to spend on traveling and waiting. Considering the combined effect of location and price on the firm's profit while taking into account the demand elasticity, our model provides managerial insights about how the interactions of these decision variables impact the firm's profit. Third, we extend this single facility problem to a multiple facility problem. Customers have multiple choices for service. The firm maximizes its profit subject to customers' choice criteria. We propose a system optimization model where customers cooperate with the firm to choose the facility for service and a user equilibrium model where customers choose the facilities that provide the best utility to them. We investigate the properties of the optimal solutions. Heuristic algorithms are developed for the user equilibrium model. Our results show that capacity planning and location decisions are closely related to each other. When customers are highly sensitive to waiting time, separating capacity planning and location decisions could result in a highly suboptimal solution.
Boredom Escapes Us: A Cultural Collage in Eleven Storeys
Keywords: boredom
sociology

Few sociologists have addressed the concept of boredom despite interest in the subject and experience of boredom from psychology, philosophy, the arts and popular culture. Classical sociological concepts of alienation, anomie and disenchantment are related to boredom, but do not address it directly. The history of the word boredom itself is not clear, though it appears it was first used in the late 19th century. Most authors agree that an increase in individualism and the concomitant rise in secularization, combined with industrial changes in labour and increased bureaucracy, help to explain a perceived increase in the experience of boredom. This dissertation is a phenomenological exploration of boredom, informed by the writings of Martin Heidegger and Walter Benjamin on the subject. Inspired by Benjamin’s method of literary montage, from his monumental Passagenwerk, I construct a cultural collage of the subject of boredom. I use the metaphor of storeys (the levels of a building) as an organizing device to construct the empirical work of this project. These storeys include a consideration and analysis of: billboards, internet advertising, the reflections of an overseas development worker, art installations, a poem, a greeting card, a play, song lyrics and Kafka’s short story character, the hunger artist. Each storey serves to inspire a sociological meditation on the subject of boredom, all of which are grounded in the historical, social and philosophical reviews in the first four chapters. These extensive reviews, as well as the eleven storeys, contribute a preliminary sociological analysis of the ambiguous yet ubiquitous experience of boredom in modernity.
Pesticide Fate in Different Climates
Keywords: Pesticides
Fate
Temporal trends
Surface sorption artefact

Passive air samplers (PAS) using XAD-resin were deployed at a wide variety of sites around the world for four years to asses the spatial and temporal trends of legacy organochlorine pesticides (OCPs) and current use pesticides (CUPs) in the global atmosphere. Legacy OCPs are prevalent in developing countries, whereas certain CUPs dominate in North America and Europe. OCP levels are declining world wide. Concentrations from the XAD-based PAS agreed with those from polyurethane foam (PUF) disk PAS within a factor of 4 for most sites. The comparison revealed that the sampling rate of the PUF-based PAS is more dependent on wind speed, whereas that of the XAD-PAS has a higher dependence on temperature. Analysis of PAS deployed across arid, subtropical Botswana showed that recent use has more impact on present day air concentrations than historical use. Year-long measurements by high volume air sampling in Botswana yielded higher HCB levels in winter, and higher endosulfan levels in summer. Those variations are neither related to temperature fluctuation nor seasonal hydrological events, and are therefore more likely caused by pesticide usage pattern. Very low levels of OCPs were found in the warm, dry, low organic matter soils of Botswana, including in soils from historical use areas. Such soils appear to have a low long-term storage capacity for pesticides allowing for rapid volatilization. They are thus not long-term sources of pesticides to the atmosphere. Endosulfan sulfate levels were observed to increase in tropical soils with increasing elevation. Water samples from high altitude cloud forests in Costa Rica contained very low concentrations of CUPs and it is unlikely that that those levels pose a threat to amphibians in cloud forests. Laboratory experiments and literature analysis showed that the inert gas stripping method for the determination of air-water partitioning equilibria is susceptible to surface sorption artifacts for chemicals with a interface-air partition coefficient log (KIA/m) > -3. Using larger bubbles reduces the surface-to-volume ratio and produces accurate air-water partition coefficients for chemicals with log (KIA/m) < -1.2.
Regulation of Homeostatic Intestinal IgA Responses by the TNF Family
Keywords: Intestinal immunology
Commensal flora
IgA
TNF superfamily
BAFF
Lymphotoxin
IgA nephropathy

The mammalian immune system has developed diverse strategies to protect the gastrointestinal tract, as this tissue locale represents a huge absorptive surface and is susceptible to microbial breach. Paradoxically, one key aspect of this protective strategy is the maintenance of selected commensal microorganisms. These commensals serve essential roles in digestion, interfere with pathogenic microbial invasion and stimulate development of the host immune system. Therefore, immune responses which deplete these commensal populations are detrimental to the host. One effective intestinal immune response which selectively promotes the survival of commensals is production of antibodies of the IgA isotype which bind to bacteria without triggering inflammatory cytokines. Proteins of the tumor necrosis factor (TNF) family such as Lymphotoxin and BAFF contribute to the induction of IgA responses. Lymphotoxin is required for generation and organization of most organized lymphoid tissues, where B cell differentiation occurs, while BAFF is necessary for B cell survival and induces B cells to produce IgA. In this thesis, I describe work I have done in examining the roles of the TNF family members Lymphotoxin, BAFF and two related TNF family member cytokines, LIGHT and APRIL, in the regulation of IgA production in mice and in humans. Specifically, LIGHT over-expression drives immense production of IgA, leading to renal deposition of immune complexes in mice. Similar to LIGHT, BAFF over-expression drives increases in IgA production in the intestine, however I have shown that the effects of the BAFF pathway on IgA hyper-production are independent of LIGHT activity. Secondly, examining the phenotype of BAFF-over-expressing mice, I have shown that this phenotype resembles human IgA nephropathy (IgAN) and is dependent on intestinal commensals. Finally, I have described a lymphotoxin-dependent chemokine system in the intestinal lamina propria that could be responsible for organizing cells for the development of IgA responses in this mucosal site.
Decomposition and Symmetry in Constraint Optimization Problems
Keywords: artificial
intelligence

This thesis presents several techniques that advance search-based algorithms for solving Constraint Optimization Problems (COPs). These techniques exploit structural features common in such problems. In particular, the thesis presents a number of innovative algorithms, and associated data structures, designed to exploit decomposition and symmetry in COPs. First, a new technique called component templating is introduced. Component templates are data structures for efficiently representing the disjoint sub-problems that are encountered during search. Information about each disjoint sub-problem can then be reused during search, increasing efficiency. A new algorithm called OR-decomposition is introduced. This algorithm obtains many of the computational benefits of decomposition without the need to resort to separate recursions. That is, the algorithm explores a standard OR tree rather than an AND-OR tree. In this way, the search algorithm gains greater freedom in its variable ordering compared to previous decomposition algorithms. Although decomposition algorithms such as OR-decomposition are effective techniques for solving COPs with low tree-width, existing decomposition algorithms offer little advantage over branch and bound search on problems with high tree-width. A new method for exploiting decomposition on problems with high tree-width is presented. This technique involves detecting and exploiting decompositions on a selected subset of the problem’s objectives. Such decompositions can then be used to more efficiently compute additional bounds that can be used by branch and bound search. The second half of the thesis explores the use of symmetries in COPs. Using component templates, it is possible to exploit dynamic symmetries that appear during search when some of the variables of a problem have been assigned a value. Symmetries have not previously been combined with decomposition in COPs. An algorithm called Set Branching is presented, which exploits almost-symmetries in the values of a variable by clustering similar values together, then branching on sets of values rather than on each single value. The decomposition and symmetry algorithms presented in this thesis increase the efficiency of constraint optimization solvers. The thesis also presents experimental results that test these algorithms on a variety of real world problems, and demonstrate performance improvements over current state-of-the-art techniques.
Fate of Current-use Pesticides in the Canadian Atmosphere
Keywords: pesticides
air sampling
atmospheric fate
environmental fate

Across Canada, and around the world, very large amounts of pesticides are produced and applied to agricultural crops each year. Although pesticide usage is declining, they are still a necessary part of industrial agriculture. Numerous pesticides have been quantified in the atmosphere, at high levels near regions of use and at lower, but still significant levels in remote regions. Some of the most persistent pesticides have been banned, but others continue to be used despite their persistence and potential for long-range transport (LRT). We have applied and refined an XAD-2 resin-based passive air sampler (PAS) to study the concentrations of pesticides in the atmosphere. A set of laboratory experiments measured the equilibria sorption coefficients for chemicals on XAD-2 resin, allowing the determination of a new predictive equation for equilibria sorption coefficients, and thus interpretation of the range of applicability of both XAD-based PAS and active air samplers (AAS). A set of field experiments were performed to compare the data obtained by both PAS and AAS, and to study the temporal trends of a wide range of pesticides in an agricultural area of southern Ontario. Because it is now apparent that XAD-PAS sampling rates can vary between compounds and with temperature, we also determined new compound-specific sampling rates for pesticides in the XAD-PAS. The XAD-PAS were deployed in two transects across Canada, one from the Great Lakes region to the Canadian Arctic, and one across southern British Columbia in four different mountain regions and at different elevations. The air concentrations of current-use pesticides were correlated with regions of their use in both transects. The variation of air concentration with elevation was correlated with local, ground-level sources in British Columbia. The LRT of pesticides was determined from the north-south transect, and correlated to their atmospheric half-lives. Historic-use pesticides such as hexachlorobenzene and hexachlorocyclohexane were found to have relatively uniform distributions in the Canadian atmosphere, while further evidence of α-hexachlorocyclohexane evaporation from oceans was observed in both transects.
Central Limit Theorem for Ginzburg-Landau Processes
Keywords: central
limit
theorem
interacting
particle
systems
decay
equilibrium
Ginzburg
Landau

The thesis considers the Ginzburg-Landau process on the lattice [special characters omitted] whose potential is a bounded perturbation of the Gaussian potential. For such processes the thesis establishes the decay rate to equilibrium in the variance sense is Cgt–d /2 + o (t –d/2), for any local function g that is bounded, mean zero, and having finite triple norm;
| g
| = [special characters omitted]
∂η(x) g
∞. The constant Cg is computed explicitly. This extends the decay to equilibrium result of Janvresse, Landim, Quastel, and Yau [JLQY99] for zero-range process, and the related result of Landim and Yau [LY03] for Ginzburg-Landau processes. The thesis also considers additive functionals [special characters omitted]g(ηs)ds of Ginzburg-Landau processes, where g is a bounded, mean zero, local function having finite triple norm. A central limit is proven for a–1(t) [special characters omitted] g(ηs)ds with a(t) = [special characters omitted] in d ≥ 3, a(t) = [special characters omitted] in d = 2, and a(t) = t3/4 in d = 1 and an explicit form of the asymptotic variance in each case. Corresponding invariance principles are also obtained. Standard arguments of Kipnis and Varadhan [KV86] are employed in the case d ≥ 3. Martingale methods together with L2 decay estimates for the semigroup associated with the process are employed to establish the result in the cases d = 1 and d = 2. This extends similar results for noninteracting random walks (see[CG84]), the symmetric simple exclusion processes (see [Kip87]), and the zero-range process (see [QJS02]).
Millimeter-wave Analog to Digital Converters: Technology Challenges and Architectures
Keywords: Analog to Digital Converter
mm-Wave Circuit
Track and Hold Amplifier
SiGe
CMOS
Data Converter
TIALA
Retimer

While data converters have been around for nearly nighty years, mm-wave data converters are still in their infancy. Only recently the 40-GHz sampling barrier was broken with the introduction of the next generation high-speed sampling oscilloscopes. Meanwhile, data communication is the main driving force behind mm-wave data converter development. As with any mm-wave circuit, designers must go beyond simply relying on technology advancement to archives acceptable performance. Careful device and passive modeling is critical and systematic design methodology may o er repeatable and scalable mm-wave designs. In this thesis the design methodology and architectural challenges of mm-wave ADCs are explored. Some of the fundamental mm-wave ADC building blocks such as track and hold ampli ers, data distribution networks and ip- ops are implemented in SiGe BiCMOS and CMOS technologies and characterized. Several record breaking circuits are presented along with systematic design methodology. The impact of these circuit blocks on the performance of the next generation ADCs is studied and experimentally veri ed using a 35-GS/s, 4-bit ADC-DAC chain implemented in a SiGe BiCMOS technology.
Magnetic Resonance Imaging Detected Intraplaque Haemorrhage as an Endogenous Imaging Biomarker and Therapeutic Target
Keywords: Magnetic Resonance
Intraplaque Haemmorhage

Cardiovascular diseases, such as stroke and heart attack, are one of the largest causes of death and morbidity in Canada. Atherosclerosis, or the thickening of the arterial wall, has been identified as the primary culprit lesion behind the end organ damage associated with cardiovascular diseases. Magnetic resonance imaging has taken a primary role in characterising the constituents of these atherosclerotic plaques. Of these components, MR detected intraplaque haemorrhage (IPH), or bleeding inside the vessel wall, appears to predispose a patient to future clinical events. This leads us to the conclusion that IPH is a secondary manifestation of plaque progression and complication, or somehow contributes to the complication of these atherosclerotic plaques. This thesis explores this second possibility, in line with the “iron hypothesis” of atherosclerosis which suggests that iron plays a significant, primary role in atherogenesis. In chapter two, the signal hyperintensity associated with IPH is correlated with the lipid oxidising potential of blood products in various oxidation states. It is found that the ferric paramagnetic species has a significantly greater ability to generate lipid oxide components and oxidise lipid surrogates. This finding suggests that it may be possible to alter the course of plaque progression by inhibiting the active ferric iron state. Chapter three explores an endogenous molecule, haptoglobin, whose purpose is to bind and inactivate free haemoglobin. It is shown that haptoglobin has the ability to modulate the MR signal intensity from IPH. Chapter four explores a mechanism to detect this imaging biomarker outside the MR environment using the electron paramagnetic resonance of the ferric haemoglobin. Results are shown in a custom made bench top system detecting ferric haemoglobin in an in vitro sample. This thesis provides more evidence for the iron hypothesis of atherosclerosis and explores methods of inhibiting and detecting this biomarker of disease.