VictorJuiz/thesis huggingface dataset:
Investigating the Role of Apelin Receptor Signaling in Zebrafish Myocardial Progenitor Development
Keywords: cardiac development
developmental biology

In vertebrates, the heart is the first organ to form and function. The basic steps and molecular pathways involved in heart development are highly conserved. Myocardial progenitor-fated cells are among the first cells to migrate during gastrulation away from the primitive streak. These cells move bilaterally to populate the heart-forming region (HFR) in the anterior lateral plate mesoderm (ALPM). Once cells have reached the HFR, they receive the signals necessary to differentiate into myocardial progenitor cells. It is clear that the development of myocardial progenitor cells entails the migration of cells from the lateral embryonic margin to the ALPM. However, it is unclear whether cells are specified for a myocardial progenitor fate early in embryogenesis, a step that may promote their migration specifically to the ALPM, or whether the migration of cells to the ALPM alone is sufficient for differentiation into myocardial progenitor cells. A zebrafish mutant, grinch (grn), was indentified in which there is a defect in the development of myocardial progenitor cells. The mutation resulting in the grn phenotype was mapped to the gene encoding the G protein-coupled receptor Apelin receptor b (Aplnrb). I have used the aplnrb mutant embryo, as well as morpholino-mediated knockdown (morphant embryos) of aplnrb, and its paralog aplnra, to determine the function of Aplnr signaling in myocardial progenitor development. Results demonstrate that Aplnr signaling is necessary for the migration of cells from the lateral embryonic margin of the zebrafish embryo to the heart-forming region. Interestingly, this entails a novel cell-non-autonomous function for Aplnr signaling. Furthermore, both the only identified ligand for the receptor, Apelin, and the canonical mediators of Aplnr signaling, Gαi/o proteins, appear to be dispensable for this process. Loss of Aplnr signaling also appears to affect embryonic patterning of the early embryo through subtle perturbations of Nodal, Wnt, and Bmp signaling and attenuation of Nodal signaling can partially recapitulate the aplnr morphant cardiac phenotype. Taken together, my results suggest that Aplnr signaling plays a role in creating an environment that allows for the migration of cells to the heart-forming region, possibly through the regulation of early embryonic patterning.
Related and Conflated: A Theoretical and Discursive Framing of Multiculturalism and Global Citizenship Education in the Canadian Context
Keywords: Global Citizenship Education
Critical Multiculturalism
Citizenship Education
Situated Philosophy of Education
Critical Discourse Analysis

There is a public perception that Canada is an ideal place for cultivating global citizenship because of its culturally plural demographics and official policies of multiculturalism. Global Citizenship Education (GCE) is a growing field in Canadian education and is an explicit focus in the Alberta social studies curriculum. This thesis brings together four conversations within which multiculturalism and GCE are both related and conflated: (a) the public perceptions of Canada as a model of cultural diversity and global citizenship, (b) the scholarly discussions of GCE and multiculturalism, (c) the policy context where multiculturalism is set alongside GCE, and (d) the practical ways that the two are mutually related in curriculum and lesson documents. There are four interrelated sections to this thesis; each identifies the tensions inherent to multiculturalism, GCE, and the perceived relationship between these fields. First is a wider philosophical and theoretical framing of the topic. Second is the examination of educational research on the topic. Third is a critical discourse analysis of policy, curriculum, and lesson plan documents in the province of Alberta. Last is a synthesis of the findings from all three sections. The analysis finds that there are philosophical and ideological tensions inherent to both fields and to the relationships between them. This contributes to conceptual and ideological conflation and confusion. This finding raises some important concerns in terms of possibilities and constraints to thinking about cultural diversity and social inequities in new ways. It highlights how multicultural contexts of GCE can lead to the recreation of tensions, conflation, and ambiguity. However, the Alberta context demonstrates that a multicultural context can also open critical spaces and possibilities for GCE through engagements with tensions and complexities. Thus this thesis contributes theoretically, by presenting a framework and perspective for interrogating and critically inquiring into the relationship between the two fields. It also contributes to the policy and curriculum discussions in educational research and practice by highlighting the importance of foregrounding key tensions inherent to each field and by identifying the potential negative consequences of leaving these tensions implicit.
Tree Spanners of Simple Graphs
Keywords: graph spanner

A tree t-spanner T of a simple graph G is a spanning tree of G, such that for every pair of vertices of G their distance in T is at most t times their distance in G, where t is called a stretch factor of T in G. It has been shown that there is a linear time algorithm to find a tree 2-spanner in a graph; it has also been proved that, for each t > 3, determining whether a graph admits a tree t-spanner is an NP-complete problem. This thesis studies tree t-spanners from both theoretical and algorithmic perspectives. In particular, it is proved that a nontree graph admits a unique tree t-spanner for at most one value of stretch factor t. As a corollary, a nontree bipartite graph cannot admit a unique tree t -spanner for any t. But, for each t, there are infinitely many nontree graphs that admit exactly one tree t-spanner. Furthermore, for each t, let U( t) be the set of graphs being the union of two tree t-spanners of a graph. Although graphs in U(2) do not have cycles of length greater than 4, graphs in U(3) may contain cycles of arbitrary length. It turns out that any even cycle is an induced subgraph of a graph in U(3), while no graph in U(3) contains an induced odd cycle other than a triangle; graphs in U(3) are shown to be perfect. Also, properties of induced even cycles of graphs in U(3) are presented. For each t > 3, though, graphs in U( t) may contain induced odd cycles of any length. Moreover, there is an efficient algorithm to recognize graphs that admit a tree 3-spanner of diameter at most 4, while it is proved that, for each t > 3, determining whether a graph admits a tree t-spanner of diameter at most t +1 is an NP-complete problem. It is not known if it is hard to recognize graphs that admit a tree 3-spanner of general diameter; however integer programming is employed to provide certificates of tree 3-spanner inadmissibility for a family of graphs.
Structural Variation in the Human Genome
Keywords: human genetics
structural variation
whole genome sequencing
personal genome
bioinformatics
copy number variation
inversion
next generation sequencing
mechanism of formation
biotechnology

The study of variation found in DNA is fundamental in human genetic studies. Single nucleotide polymorphisms (SNPs) are simple to document because they can be captured in single DNA sequence reads. Larger structural variation including duplications, insertions, deletions, termed as copy number variation (CNV), inversions and translocations are more challenging to discover. Recent studies using microarray and sequencing technologies have demonstrated the prevalence of structural variation in humans. They can disrupt genic and regulatory sequences, be associated with disease, and fuel evolution. Therefore, it is important to identify and characterize both SNPs and structural variants to fully understand their impact. This thesis presents the analysis of structural variation in the human genome. The primary DNA sample used for my experiments is the DNA of J. Craig Venter, also termed HuRef. It was the first personal human genome sequenced. I combined computational re-analysis of sequence data with microarray-based analysis, and detected 12,178 structural variants covering 40.6 Mb that were not reported in the initial sequencing study. The results indicated that the genomes of two individuals differed 1.3% by CNV, 0.3% by inversion and 0.1% by SNP. Structural variation discovery is dependent on the strategy used. No single approach can readily capture all types of variation, and a combination of strategies is required. I analyzed the formation mechanisms of all HuRef structural variants. The results showed that the relative proportion of mutational processes changed across size range: the majority of small variants (<1kb) were associated with nonhomologous processes and microsatellite events; median size variants (<10kb) were commonly related to minisatellites and retrotransposons; and large variants were associated with nonallelic homologous recombination. Eight new breakpoint-resolved HuRef inversions were genotyped in populations to elucidate these understudied variants. I discovered that the structures of inversion could be complex, could create conjoined genes, and their frequencies could exhibit population differentiation. The data here contributes to our understanding of structural variation in humans. It shows the need to use multiple strategies to identify variants, and it emphasizes the importance to examine the full complement of variation in all biomedical studies.
Outcome and Predictors of In-hospital 6-week Mortality associated with Invasive Methicillin Resistant Staphylococcus aureus (MRSA) versus Methicillin Sensitive Staphylococcus aureus (MSSA) Infection
Keywords: MRSA
outcomes
mortality
staphylococcus aureus

Background: Staphylococcus aureus (SA) infections are common and important within the hospital environment. The case fatality rate of invasive Staphylococcus aureus (SA) infections is between 20-40%. Whether the infection is due to methicillin resistant SA (MRSA) or methicillin sensitive SA (MSSA) may determine outcomes. Literature to date is inconclusive regarding whether antimicrobial resistance in SA affects patient outcomes. Host factors, infection-host interactions, and treatment-related factors may also influence case fatality. Objectives: The purpose of this study was to determine if patients with MRSA invasive infections were more likely to die than those with MSSA invasive infections, and what factors were associated with death. Methods: A retrospective matched case control study was designed, comparing cases of MRSA with controls of MSSA invasive disease from hospitals participating in the Canadian Nosocomial Infection Surveillance Program (CNISP). Two analyses were run: the first, to identify the variables associated with MRSA vs. MSSA infections, and the second, to determine the variables associated with death in invasive Staphylococcal aureus (S. aureus) infections. Backward logistic regression analysis was used for the MRSA vs. MSSA analysis and a hierarchical logistic regression model for assessment of risk factors for death. Results: In the logistic regression MRSA model the variables: recent prior use of antibiotics, Charlson Comorbidity Index score > 2 and not having received appropriate empiric antibiotics were associated with MRSA vs. MSSA infections. The hierarchical model identified older age, higher CCI scores, immunosuppression, bloodstream infection, septic shock, neurological dysfunction and not receiving appropriate empiric antibiotic as associated with death. MRSA infection was not more likely to be associated with increased mortality than MSSA infection. Those with a resistant infection (MRSA) however, were less likely to receive appropriate empiric antibiotic treatment. Conclusions: Appropriate empiric antibiotics are the most important and only modifiable risk factor identified. Elderly patients who are on immunosuppressive drugs and have chronic comorbid conditions need to be monitored and screened more often since they are more at risk for death than others.
Low-power Charge-pump Based Switched-capacitor Circuits
Keywords: Switched-Capacitor Circuits
Charge-Pump
Delta-Sigma Modulator

In this thesis, low-power charge-pump (CP) based switched-capacitor (SC) circuits are proposed. The approach is validated in SC integrators and gain stages, and is shown to achieve power savings compared to conventional SC circuits. For the same thermal noise and settling performance, a CP based integrator with N sampling capacitors ideally consumes N^2 times lower OTA power compared to a conventional integrator. Practical effects such as the OTA partial slew-rate limitation and the CP parasitics reduce the power savings. In the case of a SC gain stage, reduction in power savings also occurs due to the load capacitance from the next stage. A prototype delta-sigma modulator employing a CP integrator at the front-end is fabricated. Experimental results demonstrate that the CP based ADC achieves the same performance as a conventional ADC while consuming three times lower OTA power in the front-end integrator. The CP ADC achieves 87.8 dB SNDR 89.2 dB SNR and 90 dB DR over a 10 kHz bandwidth while consuming 148 uW from a 1.2 V power supply. The conventional ADC has similar performance but dissipates 241 uW. The CP ADC figure-of-merit (FOM) is 0.369 pJ/conv-step, which is almost 40% lower than that of the conventional ADC.
Femtosecond Laser Fabrication of Optimized Multilayered Volume Diffractive Optical Elements
Keywords: Ultrafast lasers
Diffractive Optics
Talbot self-imaging
Volume gratings

Diffractive optical elements (DOEs) serve an important function in many dynamic and static optical systems. The theory and design of surface diffractive structures are well understood and practically applied at high spatial and phase resolution for a wide range of optical applications in science and industry. However, these structures normally only harness phase modulation of uniform fields for the beam diffraction and therefore limit their range of application, as well as being susceptible to surface damage. Multilayered volume diffractive elements offer a powerful opportunity to harness both phase and amplitude modulation for benefits in diffraction efficiency and beam shaping. However, multilayered combinations have been difficult to fabricate and provide only weak diffraction for phase gratings with low refractive index contrast. The advent of femtosecond laser writing inside transparent media has enabled the facile embedding of optical devices such as waveguides and diffractive optics into novel three-dimensional geometries that offer advanced functionality with compact design. In this work, femtosecond laser writing is pushed to the limits of forming high resolution phase elements with sufficiently strong refractive index contrast on which to develop volume phase gratings with the highest diffractive efficiency. The formation of both positive and negative zones of refractive index contrast together with rapid Talbot self imaging inside weakly contrasting phase gratings are major challenges here diminish the efficiency of assembled gratings. A method of strategic layering of otherwise weakly diffracting gratings onto Talbot planes is introduced to demonstrate, in FDTD models, the definitive enhancement of overall diffraction efficiency. A systematic optimization of laser writing in fused silica verify this enhancement or diminishment with weak volume gratings assembled on aligned or misaligned on Talbot planes. Advanced laser beam control methods were further demonstrated that underpin new direction for the facile assembly of highly functional DOEs that can exploit coherent light diffraction for opportunities in improving the performance of holographic devices and extend further to the powerful combination of phase and amplitude modulation control that is potentially available in a single optical device, thereby opening new directions for the design and fabrication of robust and strongly diffracting volume optical devices.
Creating Criminality: The Intensification of Institutional Risk Aversion Strategies and the Decline of the Bail Process
Keywords: institutional risk
organizational culture
workgroup
efficiency
bail
judicial interim release
remand
adjournment
surety
conditions of release
youth
Youth Criminal Justice Act

The question of whether or not to release an accused on bail pending case resolution involves an evaluation of the risk the accused poses to the community. In addition to this evaluation, the risk posed to the reputation of the criminal justice system should the accused re-offend while on bail has come to influence the timeliness of the bail decision as well as the conditions of the release order. It appears that questions of institutional risk have intensified strategies of process, whereby the bail decision making process has come to take considerably longer as court actors postpone making the release decision. This organizational culture of risk aversion is evidenced in the growing remand population, the dominance of adjournment requests, the presumption of surety supervision, as well as the imposition of numerous restrictive conditions of release that are questionably related to the grounds for detention and allegations of the offence. Due to the additional protections contained in the Youth Criminal Justice Act (YCJA), the expectation is bail should be more liberally used for youths. However, despite the additional legislated protections, bail practices for both adults and youths are operating in remarkably similar ways. Indeed, it appears that routine bail practices for both adults and youths are inconsistent with the essential principles of the bail process. In Canada there is a presumption in favour of release on bail and a presumption of release on the least restrictive form of release appropriate in the circumstances. Despite these principles there has been a relatively steady increase in the size of the remand population in Canada. Focusing on the situation in Ontario, this dissertation examines the bail process in an effort to understand how the remand population has come to exceed the population of sentenced prisoners in provincial prisons for both adults and youths.
Interrogation of Glioma Ontogeny using Mouse Models
Keywords: Gliomas
Mouse models

Glioblastoma Multiforme (GBM) is the most common and lethal of human primary central nervous system tumours, with a median survival of 14-16 months despite surgery, radiation and chemotherapy. A reason for this dismal prognosis is insufficient understanding of the ontogeny of GBMs, which are highly heterogeneous at a pathological level. This pathological diversity, between and within GBMs as well as varying grades of gliomas, is not fully explained on the grounds of an oncogenic stimulus. Interaction with the tumour microenvironment, as well as inherent characteristics of the tumour cell of origin are likely a source of this heterogeneity. In this thesis we describe the use of a novel mouse model which integrates Cre-Lox mediated and Tet-regulated gene expression. This system in combination with germline and somatic strategies has enabled us to interrogate how the state in glial development and the region in the brain where transformation occurs influence the process of gliomagenesis. The findings of this thesis suggest that the state of glial development at which a mutation is introduced is an important determinant of gliomagenesis. In support of this, we showed that early progenitors in the radial glial lineage are more susceptible to transformation than those, which have committed to a gliogenic lineage and are presumably further along in the process of differentiation. Highlighting the interplay between genetic alterations and the molecular changes that accompany the process of differentiation. Despite findings that suggest that neurogenic regions of the adult brain are more susceptible to transformation, we show that this is not always the case and instead, transformation is dependent on an interaction between specific combinations of genetic mutations and susceptible cell types regardless of the region of origin. Results from this thesis highlight the need to view the tumourigenic process of gliomas in the context of normal brain development as the cell context of oncogene expression may determine the phenotype and biologic aggressiveness of the tumour. Thus, the results of genetic or epigenetic alterations leading to brain tumours may be quite different in different cells of the hierarchy, suggesting unique treatment targets and strategies depending on the cell of origin.
The Distribution of Values of Logarithmic Derivatives of Real L-functions
Keywords: logarithmic derivatives
L-functions

We prove in this thesis three main results, involving the distribution of values of L′/L(σ,χ D), D being a fundamental discriminant, and χ D the real character attached to it. We prove two Omega theorems for L′/L(1,χ D), compute the moments of L′ /L(1,χD) and construct, under GRH, for each σ > 1/2, a density function [special characters omitted]σ such that #{D fundamental discriminants, such that |D| ≤ Y, and α ≤ L′/L(σ,χ D) ≤ β}[special characters omitted].
Becoming a Sustainability Chef: An Empirical Model of Sustainability Perspectives in Educational Leaders
Keywords: education for sustainable development (ESD)
sustainability learning
environmental education
sustainability practice
EcoSchools
educators' perspectives

This dissertation reports a study exploring adult engagement with sustainability learning practices in EcoSchools-certified secondary schools in Canada, Lithuania and Sweden as a means towards shaping a liveable future. The study is situated in the area of education for sustainable development. The study design was initially based on an interest in revealing specific practices of sustainability education as a means of improving the relationship between environmental impact and wealth. While echoing findings in the existing literature, this research contributes to the development of the field through insight into the perspectives that adults bring to sustainability education. Primary data collected in the spring of 2006 were recorded (mostly single) semistructured interviews with 30 individuals (national coordinators, caretakers, teachers and administrators), including 10 Canadians from four schools, 14 Lithuanians from four schools, and six Swedes from two schools. Four phases of qualitative analysis were used on the data: initial transcript coding and trends; précis document trends; a six-stage model of interview responses allowing vertical (between question) and horizontal (between stage) comparisons; word maps of subthemes as a scaffold to detail participants’ four primary views (long, wide, deep, dynamic) regarding sustainability. Ultimately, the results of this study point less than expected to revealing specific transferable practices regarding success and challenge in EcoSchools. Rather, these findings provide some insight into a means of shaping a sustainable future through an individual’s sustainability perspective: a living responsiveness based on a sense of connection, supported by improved sustainability cognition, and realized through sustainability practice and considered engagement.