VictorJuiz/thesis huggingface dataset:
Setting Accommodation and Item Difficulty

This study used multilevel measurement modeling to examine the differential difficulties of math and reading items for Grade 6 students participating in Ontario’s provincial assessment in 2005-2006, in relation to whether they received a setting accommodation, had a learning disability (LD), and spoke a language in addition to English. Both differences in difficulty between groups of students for all items (impact) and for individual items (differential item functioning) were examined. Students’ language backgrounds (whether they spoke a language in addition to English) were not significantly related to item difficulty. Compared to non-accommodated students with LD, math and reading items were relatively difficult for accommodated students with LD. Moreover, the difference in overall impact on math items was larger than on reading items for accommodated and non-accommodated students with LD. Overall, students without LD and who did not receive a setting accommodation outperformed students with LD and/or who received a setting accommodation as well as accommodated students without LD. It is important to note that, because this was an operational test administration, students were assigned to receive accommodations by their schools based on their individual needs. It is, therefore, not possible to separate the effect of the setting accommodation on item difficulty from the effects of other differences between the accommodated and non-accommodated groups. The differences in math and reading item difficulties between accommodated and non-accommodated students with LD may be due in part to factors such as comorbidity of LD and attention deficit hyperactivity disorder (ADHD) or a possible mismatch between the setting accommodation and the areas of disabilities. Moreover, the results of the present study support the underarousal/optimal stimulation hypothesis instead of the premise of the inhibitory control and attention for the use of setting accommodation. After controlling for the impact across all items of setting accommodation and LD, several math and reading items were found to exhibit differential item functioning (DIF). The possible sources of DIF were (1) math items that were not adherent to specific item-writing rules and (2) reading items targeting different types of comprehension. This study also found that the linguistic features of math items (total words, total sentences, average word length, monosyllabic words for math) and reading items (word frequency, average sentence length, and average words per sentence for reading) were associated with math and reading item difficulties for students with different characteristics. The total sentences and average word length in a math item as well as total words in a reading item significantly predicted the achievement gap between groups. Therefore, the linguistic features should be taken into account when assessments are developed and validated for examinees with varied characteristics.

Keywords: accommodations
assessments
educational measurement
item difficulty
large-scale assessment
math
reading
setting accommodation
Advisor: Childs, Ruth A.
LA-Courant Algebroids and their Applications

In this thesis we develop the notion of LA-Courant algebroids, the infinitesimal analogue of multiplicative Courant algebroids. Specific applications include the integration of q- Poisson (d, g)-structures, and the reduction of Courant algebroids. We also introduce the notion of pseudo-Dirac structures, (possibly non-Lagrangian) subbundles W ⊆ E of a Courant algebroid such that the Courant bracket endows W naturally with the structure of a Lie algebroid. Specific examples of pseudo-Dirac structures arise in the theory of q-Poisson (d, g)-structures.

Keywords: Differential Geometry
Mathematical Physics
Advisor: Meinrenken, Eckhard
Maternal Macronutrient Intakes, Glucose Metabolism during Pregnancy and Metabolic Hormones in Human Milk

Substantial evidence supports a role of diet in glucose metabolism, but only a few reports have investigated the impact of diet during pregnancy on risk of gestational diabetes (GDM). Although metabolic hormones have been detected in milk, no studies have investigated the impact of maternal metabolic status assessed during pregnancy on insulin and adiponectin concentrations in human milk. The purpose of this thesis was to investigate the association of maternal macronutrient intakes with metabolic status during pregnancy and its subsequent impact on human milk hormones. Participating women (n=216) underwent a 3-hour oral glucose tolerance test at 30 (95% confidence interval [CI] 25, 33) weeks gestation, recalled their second trimester dietary intake, and donated early (the first week) and mature (3 months postpartum) milk. Higher vegetable and fruit fiber intake was associated with reduced insulin resistance (beta±SE -0.100±0.029, p=0.0008) and increased insulin sensitivity (0.029±0.012, p=0.01) among those with a family history of type 2 diabetes. Lower % carbohydrate and higher % total fat were associated with increased GDM risk (odds ratio 0.60 [95% CI 0.40, 0.90] and 1.61 [1.06, 2.44], respectively). Prenatal metabolic abnormalities including higher pregravid body mass index (beta±SE 0.053±0.014, p=0.0003), in addition to gravid hyperglycemia (0.218±0.087, p=0.01), insulin resistance (0.255±0.047, p<0.0001), lower insulin sensitivity (-0.521±0.108, p<0.0001), and higher serum adiponectin (0.116±0.029, p<0.0001) were associated with higher insulin in mature milk. Obstetrical measures including nulliparity (0.171±0.058, p=0.004), longer duration of gestation (0.546±0.146, p=0.0002), and unscheduled caesarean section (0.387±0.162, p=0.02) were associated with higher adiponectin in early milk. Holder pasteurization, a process recommended by the Human Milk Bank Association of North America before distributing human donor milk, reduced milk adiponectin and insulin concentrations by 32.8% and 46.1%, respectively (both p<0.0001). In conclusion, the distribution of macronutrient intakes during pregnancy was associated with risk for abnormal glucose metabolism later in pregnancy. In addition, maternal prenatal metabolic abnormalities were associated with high insulin concentrations in mature milk, while only obstetrical parameters were associated adiponectin concentrations in early milk. Our findings support the need for continued work to determine optimal prenatal nutritional strategies to prevent GDM and subsequently to improve infant nutrition.

Keywords: pregnancy
human milk
macronutrient
glucose metabolism
gestational diabetes
adiponectin
insulin
lactation
Advisor: Hanley, Anthony James Gordon
O'Connor, Deborah Louise
Processing and Characterization of PCL- and PLGA-HA Composites for Bone Tissue Engineering

The focus of this research is to advance the processing techniques of fabricating scaffolds for tissue engineering and to gain a better understanding of the scaffold properties and behaviours. To achieve these objectives, the fundamental properties of two widely used biomaterials, poly(lactide-co-glycolide acid) (PLGA), poly(ε-caprolactone) (PCL), and their composites with hydroxyapatite were examined. Though increasing the mechanical properties of the bulk polymers, the addition of hydroxyapatite did not affect the thermal and viscoelastic properties, suggesting little interactions may exist between the polymer and the particles. Interestingly, though the addition of the fillers increased the mechanical properties of the bulk materials, the particles worsened the mechanical properties of gas foamed/salt leached scaffolds possibly due to the struts of the porous structure having similar thicknesses as the particles. In such a case, the filler acted as stress raisers and decreased the properties of the struts. The viscoelasticity of the scaffolds was also not affected by the fillers but was affected by the testing environment. An aqueous environment caused the PLGA, but not PCL, to transition such that the porous structure was altered. These results suggest that PLGA may not be ideal for scaffolds for load bearing applications. For electrospinning, a parametric study was performed to control the scaffold morphology, but more importantly, a novel process to fabricate 3D electrospun scaffolds was developed. The novel technique exploited the plasticizing effect of pressurized carbon dioxide on the polymer such that multiple layers of the thin meshes can be sintered together without the use of heat. The process was optimized for adhering layers of PLGA and its composite with nano-hydroxyapatite, and these scaffolds have a high open-porosity and better mechanical properties compared to the gas foamed/salt leached scaffolds. Finally, a model was derived for the viscoelasticity of the bulk materials and their scaffolds by applying fractional calculus on the classical standard linear solid model based on a system of springs and dashpots. The model fitted the data, and correlations between the static mechanical properties and the fitting parameters were found such that by performing static mechanical tests, the viscoelastic behaviours can be approximated.

Keywords: Tissue Engineering
Polymer
Viscoelasticity
Processing
Advisor: Naguib, Hani E.
Sefton, Michael
Cooperative Localization and Mapping in Sparsely-communicating Robot Networks

This thesis examines the use of multiple robots in cooperative simultaneous localization and mapping (SLAM), where each robot must estimate the poses of all robots in the team, along with the positions of all known landmarks. The robot team must operate under the condition that the communication network between robots is never guaranteed to be fully connected. Under this condition, a novel algorithm is derived that allows each robot to obtain the centralized-equivalent estimate in a decentralized manner, whenever possible. The algorithm is then extended to a decentralized and distributed approach where robots share the computational burden in considering different data association hypotheses in generating the centralized-equivalent consensus estimate.

Keywords: Multi-robot System
Simultaneous Localization and Mapping (SLAM)
Mobile Robotics
Networked Robotics
Advisor: Barfoot, Timothy D.
Liu, Hugh
Modern Foundations of Light Transport Simulation

Light transport simulation aims at the numerical computation of the propagation of visible electromagnetic energy in macroscopic environments. In this thesis, we develop the foundations for a modern theory of light transport simulation, unveiling the geometric structure of the continuous theory and providing a formulation of computational techniques that furnishes remarkably efficacy with only local information. Utilizing recent results from various communities, we develop the physical and mathematical structure of light transport from Maxwell's equations by studying a lifted representation of electromagnetic theory on the cotangent bundle. At the short wavelength limit, this yields a Hamiltonian description on six-dimensional phase space, with the classical formulation over the space of "positions and directions" resulting from a reduction to the five-dimensional cosphere bundle. We establish the connection between light transport and geometrical optics by a non-canonical Legendre transform, and we derive classical concepts from radiometry, such as radiance and irradiance, by considering measurements of the light energy density. We also show that in idealized environments light transport is a Lie-Poisson system for the group of symplectic diffeomorphisms, unveiling a tantalizing similarity between light transport and fluid dynamics. Using Stone's theorem, we also derive a functional analytic description of light transport. This bridges the gap to existing formulations in the literature and naturally leads to computational questions. We then address one of the central challenges for light transport simulation in everyday environments with scattering surfaces: how are efficient computations possible when the light energy density can only be evaluated pointwise? Using biorthogonal and possibly overcomplete bases formed by reproducing kernel functions, we develop a comprehensive theory for computational techniques that are restricted to pointwise information, subsuming for example sampling theorems, interpolation formulas, quadrature rules, density estimation schemes, and Monte Carlo integration. The use of overcomplete representations makes us thereby robust to imperfect information, as is often unavoidable in practical applications, and numerical optimization of the sampling locations leads to close to optimal techniques, providing performance which considerably improves over the state of the art in the literature.

Keywords: light transport simulation
geometric mechanics
reproducing kernel Hilbert space
Advisor: Fiume, Eugene
Executive Function, Iowa Gambling Task Decision Making and Suicide Risk in Women with Borderline Personality Disorder

Neuropsychological deficits may perpetuate the risk and chronicity of psychiatric disorder. Borderline Personality Disorder, characterized by significant suicide risk, intense affect and behavioural dysregulation, is frequently associated with the executive function (EF) deficits of decision making and inhibitory control. However, the role of inhibitory control on decision making remains poorly understood. This study examined the relationships among working memory, cognitive and motor inhibitory control, and IGT decision-making performance in 41 women with BPD and 41 healthy controls. Associations among EF and suicide risk were also explored. Experimental tasks included the Iowa Gambling Task, Digit Span, Stroop and Stop Tasks, and Raven’s Matrices. Only IGT decision-making deficits distinguished BPD subjects from healthy controls. Weaker yet normal range IQ and EFs in BPD women did not explain their disadvantageous IGT performance. Contrary to expectations, IGT deficits in BPD women did not predict any suicidal risk; however, intact interference control was as sensitive to suicidal risk as was depression. Normal interference control was associated with a reduction in suicide risk. While IGT decision making may be a marker for BPD, Stroop interference control is more sensitive to suicide risk and may represent a vulnerability for suicide that exists beyond psychiatric diagnosis.

Keywords: Executive Function
Iowa Gambling Task
Stroop Interference
Borderline Personality Disorder
Suicide Risk
Advisor: Links, Paul
The Pure Virtual Braid Group is Quadratic

If an augmented algebra K over Q is filtered by powers of its augmentation ideal I, the associated graded algebra grK need not in general be quadratic: although it is generated in degree 1, its relations may not be generated by homogeneous relations of degree 2. In this thesis we give a sufficient criterion (called the PVH Criterion) for grK to be quadratic. When K is the group algebra of a group G, quadraticity is known to be equivalent to the existence of a (not necessarily homomorphic) universal finite type invariant for G. Thus the PVH Criterion also implies the existence of a universal finite type invariant for the group G. We apply the PVH Criterion to the group algebra of the pure virtual braid group (also known as the quasi-triangular group), and show that the corresponding associated graded algebra is quadratic, and hence that these groups have a universal finite type invariant.

Keywords: Pure Virtual Braids
Quadraticity
Graded 1-Formal
Universal Finite Type Invariant
Advisor: Bar-Natan, Dror
Social Capital and Relational Coordination in Outpatient Clinics

Coordination is a vital component in health care provision and teamwork. The need for better coordination is particularly prominent in outpatient setting where patients assume the primary responsibility to follow-up on their own health care, especially when treatment is complex and lengthy in duration. Relational coordination represents a type of informal coordination process reinforced by communication and supportive relationships. This concept has been associated with enhanced interprofessional team performance, including patient care outcomes. This study aimed to examine the theoretical underpinnings of relational coordination in the outpatient setting using social capital theory. It was hypothesized that social capital, resources embedded within network of relationships, would predict relational coordination. Additionally, social capital was hypothesized to be predicted by team tenure; and relational coordination was hypothesized to be predicted by formal coordination mechanisms. A non-experimental, cross-sectional survey design was used to examine the relationship between social capital and relational coordination. Participants (N=342) were physicians and nurses recruited from outpatient clinics in two University affiliated hospitals. Study surveys were sent to 501 nurses and 187 physicians with follow-up reminders sent at three, five and seven weeks after the initial distribution of surveys. The overall response rate was 49.71%. Study variables were measured using previously validated instruments with acceptable levels of reliability and validity. Structural equation modeling (SEM) was used for hypothesis testing. Final analysis revealed good fit of data to the hypothesized model (Chi-square=383.38, df=177, p<0.001; CFI=0.966; RMSEA=0.060; SRMR=0.0316). SEM revealed that social capital predicted both factors of relational coordination [communication (β=0.70, p<0.001); supportive relationship (β=0.81, p<0.001)], and team tenure predicted social capital (β=0.13, p<0.05). In addition, the association between team tenure and relational coordination (β=0.09, p<0.05) was found to be partially mediated by social capital. Findings of this study suggested that characteristics within relational ties are predictive of informal coordination. Administrators may facilitate teamwork through team building initiatives that foster these relational qualities, such as trust and shared language. Future research can further investigate the association between social capital and relational coordination in other health care settings, as well, in larger teams involving health care professionals in addition to physicians and nurses.

Keywords: Ambulatory care
Teamwork
Coordination
Relational coordination
Interprofessional
Multidisciplinary
Social capital
Interpersonal relationship
Advisor: Doran, Diane
Structural Characterization of F-type and V-type Rotary ATPases by Single Particle Electron Cryomicroscpy

Adenosine triphosphate (ATP) is the molecular currency of intracellular energy transfer in living organisms. The enzyme ATP synthase is primarily responsible for ATP production in eukaryotes. In archaea and some bacteria, ATP is synthesized by V-ATPase that is related to ATP synthase both in structure and function. Both of these enzymes are reversible rotary motors capable of catalyzing ATP synthesis or hydrolysis. The rotation of the central rotor, which is powered by the flow of proton (or sometimes sodium ion) down the electrochemical gradient through the membrane-bound Fo/Vo region, leads to the chemical synthesis of ATP in F1/V1 region. The F1/V1 region, on the other hand, can catalyze ATP hydrolysis, which in turn leads to proton (or sodium) pumping across the membrane through rotation of the central rotor in the opposite direction. This thesis describes structure determination of both the intact F-type and V-type enzymes using single particle electron cryomicroscopy (cryo-EM), with the aim of better understanding their overall architecture, subunit organization and the mechanism of proton translocation. Our cryo-EM structural analysis on the F-type ATP synthase from Saccharomyces cerevisiae uncovered the arrangement of subunits a, b, c, and the two dimer-specific subunits e and g within the membrane-bound region of Fo. A model of oligomerization of the ATP synthase involving two distinct dimerization interfaces was proposed.The rotor-stator interaction within the membrane-bound region of both enzymes is responsible for proton translocation. Our cryo-EM structures of the V-ATPase from Thermus thermophilus reveal that the interaction between the rotary ring (rotor) and the I-subunit (stator) is surprisingly small, with only two subunits from the ring making contact with the I-subunit near the middle of the membrane. Furthermore, the spatial arrangement of transmembrane helices resolved in subunit I can form two passageways that could provide proton access through the membrane-bound region and is consistent with a two-channel model of proton translocation.

Keywords: electron cryomicroscopy
ATP synthase
V-ATPase
membrane protein
Advisor: Rubinstein, John
The Shores of Light

The Shores of Light is an orchestral composition which seeks to explore musical processes of coherence and evolution at a deeper level. The piece charts the journey of a single musical identity across a shifting aural landscape. This thematic idea — a strongly modal melody reminiscent of both plainchant and folksong, which serves as both the initial premise and foundation for the piece — is rooted in serene yet archaic stasis. After a brief introduction, the theme is subjected to tremendous pressure by external forces, which eventually crush it beyond recognition via a series of 'destructive' harmonic, contrapuntal, and acoustic procedures. Reduced to a shadow of its former self, the theme then undergoes a series of transformations, culminating in restoration — not to its original form, but to a new identity which functions as part of a whole, a 'master' entity whose components have been discreetly but gradually cohering throughout. This final realization is glimpsed but not necessarily fulfilled (hence the "shores of light") and the work, while striving at every register to return to its initial tonic, ends on a note that suggests (somewhat ominously) the possibility of a cyclical process. It is the essential tension between hierarchical complexity (tonality) and disorder (perceptual dissonance generated either by highly chromatic aggregates, acoustic saturation, or both) which plays the most crucial role in this discourse. The evolution toward greater and greater cohesion is achieved, necessarily, in opposition to the chaotic undercurrent which threatens to overwhelm or shatter the 'cohering' elements at every turn. The final chorale is a triumph of the 'meek,' as the elements of noise and distortion (ie. disorder) are stripped away to reveal an image of luminous simplicity. The use of tonal and non-tonal material as metaphors for order and chaos seems to betray an arbitrary initial condition — after all, there is no explicit logical connection between these parameters. But order, like beauty or meaning, is a perceptual phenomenon that transcends its processes. For me, the true complexity of the tonal hierarchy lies in its emergent qualities — the layers of content that emerge from a highly structured syntax. Thus, the gradual accretion of jumbled musical letters into recognizable words, then coherent sentences, then paragraphs imbued with specific meaning, carries with its own symbolism and structural significance.

Keywords: doctor of musical arts degree
musical composition
Advisor: Hatzis, Christos