VictorJuiz/thesis huggingface dataset:
Surface Breakup of A Liquid Jet Injected Into A Gaseous Crossflow
Keywords: shear layer instability
two-phase flows
liquid jet
atomization
large eddy simulations

The normal injection of a liquid jet into a gaseous crossflow has many engineering applications. In this thesis, detailed numerical simulations based on the level set method are employed to understand the physical mechanism underlying the jet ``surface breakup''. The numerical observations reveal the existence of hydrodynamic instabilities on the jet periphery. The temporal growth of such azimuthal instabilities leads to the formation of interface corrugations, which are eventually sheared off of the jet surface as sheet-like structures. The sheets finally undergo disintegration into ligaments and drops during the surface breakup process. Temporal linear stability analyses are employed to understand the nature of these instabilities. To facilitate the analysis, analytical solutions for the flow fields of the jet and the crossflow are derived. We identify the ``shear instability'' as the primary destabilization mechanism in the flow. This inherently inviscid mechanism opposes the previously suggested mechanism of surface breakup (known as ``boundary layer stripping''), which is based on a viscous interpretation. The influence of the jet-to-crossflow density ratio on the flow stability are also studied. The findings show that a higher density jet leads to higher wavenumber instabilities on the jet surface and thereby subsequent smaller drops and ligaments. The stability characteristics of the most amplified modes (i.e., the wavenumber and corresponding growth rate) obtained from stability analyses and numerical simulations are in good agreement. The stability results of the jet also show that the density may have a non-monotonic stabilizing/destabilizing effect on the flow stability. To investigate such effect, the concept of wave resonance are employed to physically interpret the inviscid instability mechanism in two-phase flows with sharp interfaces and linear velocity profiles. We demonstrate that neutrally stable waves are formed due to the density jump in the flow, in addition to the well-known vorticity (Rayleigh) waves. Under certain conditions, such neutral waves are capable of resonating and generating unstable modes. The resonance of different pairs of neutral waves, therefore, results in either stabilizing or destabilizing effect of density variation. We predict similar reasoning behind the density behavior in the jet in crossflow configuration with smoothly varying velocity and density profiles.
Authentic Connectivity: A Pedagogue's Loving Responsibility
Keywords: authentic connectivity, bodily intelligence, elemental bridges, hemispheric transfer, biological conflict, interstitial thinking, affective idendity, emotion regulation, bridge thinking
observational pedagogy, flattened affect, pre-digital, digital and post-digital university students

I learned to authentically connect by observing the pedagogues who mentored me. My lived experience with them inspired me to base my pedagogical approach on the constructs of community and engagement that youth dismantled by displaying increasing disengagement, which transferred into disaffected relationships. This reflexive/narrative autoethnography investigates the problematic phenomenon affecting youth: the loss of authentic connectivity. I critically examine my professional journey with pre-digital, digital, and post-digital university students by analysing our common, cultural context, thereby interpreting my behaviour, thoughts, and experiences in relation to them. Hermeneutic phenomenology’s framework deepens the inquiry, as it involves a broader cultural, political, and social understanding to uncover deeper meaning in changing behaviours by reflecting on what is the lived experience of authentic connectivity for youth. My comprehensive research evidences that youth’s technological addiction has influenced rapid brain evolution, and exploded their visual and multimodal skills. Neuroscience has broadly concluded that the new forms of learning technology offers are changing the way the brain processes information. I suggest that youth are experiencing a biological conflict, the brain’s rapid evolution overwhelming more slowly evolving physical responses, effectively interfering with the flow of affective information that requires hemispheric transfer. Neither moving beyond the premise of intelligence as being predominantly brain-based, nor acknowledging the cooperative role our bodily intelligence plays, as the latter is embedded in our lived experience, the greater understanding of the whole of learning, and its ally, authentic connectivity, cannot be achieved. I submit that moving beyond the absoluteness of a purely scientific approach to the brain, and integrating both human and cognitive sciences are key in moving toward a more holistic, autonomous learning pedagogy, so to layer our understanding of the ‘person process’, that which includes whole thinking and whole being. To counter the affective devolution, which is detrimental not only to learning, but to being a well-adjusted person, this paper proposes a foundational shift in teacher training curriculum design by suggesting tools that foster an observational pedagogy, which seeks to teach those navigational skills that support higher-level analytical processes that can counteract the excessive reactions that impede learning, and teaching.
District Influence on Principals' Efficacy and Sensemaking in their School Improvement Efforts
Keywords: District Actions, District Influences, Principal's Sensemaking, Principal's Efficacy, Instructional Leadership, Principal's Leadership Practices

Part of a larger study of high-performing districts in Ontario, this mixed method (qualitative and quantitative) study identified school district actions perceived by principals to help them make sense of their leadership work and contribute to their sense of efficacy in carrying out that work. Qualitative data included interviews with 23 principals, 10 senior district leaders, and 5 trustees in two high-performing districts in the province. Narrative analysis was used to analyze these data. Quantitative data were provided by the responses of 1,563 principals and 250 senior district leaders to two forms of a survey which included sub-sets of questions about variables of special interest to this study. Descriptive statistics were used to summarize the survey results. Interview results showed that in the two study districts, each of 12 district actions framing the study were perceived to influence principals’ efficacy or principals’ sensemaking or both. Of those 12 district actions, principals in one of the two study districts identified 8 of the 12 district actions as especially influential in helping them to make sense of their work and to develop their sense of efficacy for carrying out that work; 10 of the 12 district actions were identified by principals in the second study district. Four of the 12 district actions were common across the responses of principals in both study districts including: networking interactions among principals; job-embedded and regional professional development opportunities; support from superintendents with the writing of school improvement plans; and emphasis and support with data interpretation and use for decision making processes. Except for one of these four district actions (use of evidence for decision making), survey results pointed to the same sets of district actions as particularly influential to both principals’ efficacy and sensemaking. This research adds to the understanding of what districts do that helps their school leaders work more effectively. Implications are identified for the actions of district leaders and for future research.
Anionic Nitrogen Chelate Ligands: From Molecular Self-assembly to Small Molecule Activation
Keywords: Small Molecule Activation
Chelate Ligands
Self-Assembly

This thesis examines the use of anionic nitrogen chelate ligands in coordination-driven self-assembly and small molecule activation. The two classes of anionic nitrogen chelate ligands that were explored are β-diiminate and 4,5-diazafluorenide derivatives. Chapter 2 deals with Pd β-diiminate chemistry. Chloro-bridged dimers served as versatile starting materials, and their reactivity toward pyridine and arylboronic acids was explored. An unusual transmetallation reaction with arylboronic acids triggered the self-assembly of tetrapallada-macrocycles. The formation of the self-assembled tetrapallada-macrocycles is through the generation of new Pd-C bonds. Chapter 3 deals with 4,5-diazafluorenide as an actor ligand in CO2 activation. A reversible formal insertion of CO2 into a remote ligand C-H bond was discovered. A variety of spectator metal centres were used to tune the reactivity of the actor ligand toward CO2. The spectator metal centre could even be replaced entirely with an organic group allowing for the first metal-free reversible tandem CO2 and C-H activation. Chapter 4 deals with the reactivity of dinuclear Rh 4,5-diazafluorenide-9-carboxylate complexes with dihydrogen in an attempt to reduce the trapped CO2 moiety. A series of stepwise stoichiometric reactions with H2, NMR experiments at low temperatures with added PPh3 or CO2, along with 13C-labelling experiments were conducted in an attempt to identify the products of this reaction and gain some mechanistic insight. Chapter 5 deals with using ambidentate 4,5-diazafluorene derivatives to synthesize linkage isomers, heterobimetallic complexes, and self-assembled macrocycles. The synthesis a new ligand family, 3,6-substituted 4,5-diazafluorene ligands is presented, along with coordination chemistry towards a {RuCp*}+ fragment. Finally in Chapter 6 the coordination chemistry of 3,6-diaryl substituted 4,5-diazafluorene derivatives was explored with the goal of generating low-coordinate species for the activation of small molecules, especially N2. The synthesis of the first trialkylborohydride complex of vanadium is presented.
Inferring Genetic Regulatory Networks Using Cost-based Abduction and Its Relation to Bayesian Inference
Keywords: Genetic Regulatory Networks
Cost-Based Abduction
Bayesian Network
Systems biology
recurrent neural network
Maximum a Posteriori Assignment
reasoning under uncertainty

Inferring Genetic Regulatory Networks (GRN) from multiple data sources is a fundamental problem in computational biology. Computational models for GRN range from simple Boolean networks to stochastic differential equations. To successfully model GRN, a computational method has to be scalable and capable of integrating different biological data sources effectively and homogeneously. In this thesis, we introduce a novel method to model GRN using Cost-Based Abduction (CBA) and study the relation between CBA and Bayesian inference. CBA is an important AI formalism for reasoning under uncertainty that can integrate different biological data sources effectively. We use three different yeast genome data sources—protein-DNA, protein-protein, and knock-out data—to build a skeleton (unannotated) graph which acts as a theory to build a CBA system. The Least Cost Proof (LCP) for the CBA system fully annotates the skeleton graph to represent the learned GRN. Our results show that CBA is a promising tool in computational biology in general and in GRN modeling in particular because CBA knowledge representation can intrinsically implement the AND/OR logic in GRN while enforcing cis-regulatory logic constraints effectively, allowing the method to operate on a genome-wide scale.Besides allowing us to successfully learn yeast pathways such as the pheromone pathway, our method is scalable enough to analyze the full yeast genome in a single CBA instance, without sub-networking. The scalability power of our method comes from the fact that our CBA model size grows in a quadratic, rather than exponential, manner with respect to data size and path length. We also introduce a new algorithm to convert CBA into an equivalent binary linear program that computes the exact LCP for the CBA system, thus reaching the optimal solution. Our work establishes a framework to solve Bayesian networks using integer linear programming and high order recurrent neural networks through CBA as an intermediate representation.
The Immigrant Experience, Child Feeding and Care: An Examination of the Determinants of Children's Health and Nutrition in Newcomer Families
Keywords: Household food insecurity
Immigrant Health
Child Health
Canada's Food Guide
Migration
Healthcare access

This study aims to examine how the migration experience influences newcomer mothers’ young child feeding and care practices and their children’s overall health. The thesis comprises three separate manuscripts, each of which examines one of the three intermediate determinants of the nutritional status of young children (UNICEF 1990): access to healthcare, household food insecurity, and child feeding and care practices. The research was conducted in Toronto’s Jane-Finch neighbourhood, a suburban neighbourhood home to a high density of newcomers. Thirty-two participants (16 Sri Lankan Tamil and 16 Latin American) who had migrated to Canada within the past five years as refugee claimants or family sponsored immigrants participated in the study. Data collection consisted of semi-structured interviews with women from low-income households who had a child between the ages of 1 and 5 years. Spanish and Tamil speaking interviewers interviewed each participant two or three times. Data was analyzed using a mid-level approach in which broad analytical themes are determined prior to analysis and specific themes were then generated based on participants’ perspectives and are grounded in the data. The first manuscript examines newcomer mothers’ experiences accessing physicians for their children and identifies the major gaps between mothers’ expectations and their actual experiences that lead to barriers in communication and overall patient dissatisfaction. The second manuscript demonstrates that mothers’ past experiences with food insecurity affect two aspects of the construct of food insecurity: its managed aspect and its temporal nature. This finding has implications for the measurement of food insecurity in newcomer populations. The third manuscript reveals that newcomer mothers are exposed to several parallel and often conflicting systems of knowledge concerning health and nutrition for their children, and that their utilization of Canada’s Food Guide is impeded by its failure to acknowledge alternate parallel knowledge systems. These findings can be applied to the development of social and health policy aimed at improving cultural competency in healthcare and nutrition education and at ameliorating the income constraints leading to household food insecurity.
Estimation of Volumetric Breast Density from Digital Mammograms
Keywords: Medical Physics
Radiology
Breast Cancer
Breast Density
Epidemiology
Quantitative Imaging

Mammographic breast density (MBD) is a strong risk factor for developing breast cancer. MBD is typically estimated by manually selecting the area occupied by the dense tissue on a mammogram. There is interest in measuring the volume of dense tissue, or volumetric breast density (VBD), as it could potentially be a stronger risk factor. This dissertation presents and validates an algorithm to measure the VBD from digital mammograms. The algorithm is based on an empirical calibration of the mammography system, supplemented by physical modeling of x-ray imaging that includes the effects of beam polychromaticity, scattered radation, anti-scatter grid and detector glare. It also includes a method to estimate the compressed breast thickness as a function of the compression force, and a method to estimate the thickness of the breast outside of the compressed region. The algorithm was tested on 26 simulated mammograms obtained from computed tomography images, themselves deformed to mimic the effects of compression. This allowed the determination of the baseline accuracy of the algorithm. The algorithm was also used on 55 087 clinical digital mammograms, which allowed for the determination of the general characteristics of VBD and breast volume, as well as their variation as a function of age and time. The algorithm was also validated against a set of 80 magnetic resonance images, and compared against the area method on 2688 images. A preliminary study comparing association of breast cancer risk with VBD and MBD was also performed, indicating that VBD is a stronger risk factor. The algorithm was found to be accurate, generating quantitative density measurements rapidly and automatically. It can be extended to any digital mammography system, provided that the compression thickness of the breast can be determined accurately.
A Randomized Controlled Trial Evaluating Lanolin for the Treatment of Nipple Pain Among Breastfeeding Women
Keywords: nipple pain
randomized controlled trial
breastfeeding

It is widely accepted that breast milk is the optimal source of infant nutrition. Despite the World Health Organization (WHO) recommendation of exclusive breastfeeding for the first 6 months of infant life, many women discontinue breastfeeding as a result of perceived difficulties. Nipple pain is a highly prevalent, significant reason for breastfeeding cessation. Among the numerous interventions for nipple pain, the application of lanolin is commonly recommended, with endorsement by Health Canada, The La Leche League, and International Board Certified Lactation Consultants. The few studies that have evaluated the effectiveness of lanolin on nipple pain have lacked methodologic rigor, and are thus not reliable or generalizable. As such, the purpose of this trial was to rigourously evaluate the effect of lanolin for the treatment of nipple pain among breastfeeding women. This single-site randomized controlled trial (RCT) compared the application of lanolin (treatment) to usual postpartum care (not applying lanolin) for the treatment of nipple pain. The primary outcome for this trial was the effect on pain severity, as measured by a numeric rating scale (NRS) at 4 days post-randomization. Of 186 participants, 93 were randomized to the treatment group and 93 to the usual care group. At 4 and 7 days post-randomization there were no statistically significant differences in pain scores between groups. It is noteworthy that by 7 days post-randomization there were clinically relevant decreases in nipple pain in both groups. However, there were no statistically significant differences between groups for other outcomes, including pain measured with the short-form McGill Pain Questionnaire, breastfeeding duration, breastfeeding exclusivity, and breastfeeding self-efficacy. Despite these findings, women in the treatment group were significantly more satisfied receiving lanolin for their nipple pain than those receiving usual care. Since the use of lanolin is no more effective than applying nothing to the nipples for the management of nipple pain, the widespread use of lanolin is questionable. Further research is required on the role of interventions to prevent nipple pain and damage, and the effect of anticipatory guidance on improving breastfeeding outcomes for those experiencing nipple pain in the early postpartum period.
Modulation of N-Methyl-D-Asparate Receptor by Transient Receptor Potential Melastatin Type-2 Regulates Neuronal Vulnerability to Ischemic Cell Death
Keywords: ischemia
TRPM2 NMDA

Neuronal vulnerability to ischemia is dependent on the balance between pro-survival and pro-death cellular signaling. In the latter, it is increasingly appreciated that toxic Ca2+ influx can occur not only via postsynaptic glutamate receptors, but also through other cation conductances. One such conductance, the Transient receptor potential melastatin type-2 (TRPM2) channel, is a non-specific cation channel having similar homology to TRPM7, a conductance reported to play a key role in anoxic neuronal death. The role of TRPM2 conductances in ischemic Ca2+ influx has been difficult to study due to the lack of specific modulators. Here we used TRPM2-null mice (TRPM2(-/-)) to study how TRPM2 may modulate neuronal vulnerability to ischemia. TRPM2(-/-) mice subjected to transient middle cerebral artery occlusion (tMCAO) exhibited smaller infarcts when compared to wild-type (WT) animals, suggesting the absence of TRPM2 to be protective. Surprisingly, field potentials (fEPSPs) recorded during oxidative stress in brain slices taken from TRPM2(-/-) mice revealed increased excitability, a phenomenon normally associated with ischemic vulnerability, whereas WT fEPSPs were unaffected. The upregulation in fEPSP in TRPM2(-/-) neurons was blocked selectively by an NR2A antagonist. This oxidative stress-induced increase in excitability of TRPM2(-/-) fEPSPs depended on the upregulation and downregulation of NR2A and NR2B-containing NMDARs, respectively, and augmented pro-survival signaling via Akt and ERK pathways culminating in the inhibition of the proapoptotic factor, GSK3β. Cultured hippocampal neurons from TRPM2(-/-) animals subjected to oxygen glucose deprivation had a reduction in cell death in comparison to WT neurons, demonstrating that absence of TRPM2 is protective at the neuronal level in vitro. Our results suggest that TRPM2 plays a role in downregulating pro-survival signals in central neurons and that TRPM2 channels may comprise a therapeutic target for preventing ischemic damage.
Syllabification and Phrasing in Three Dialects of Sudanese Arabic
Keywords: Arabic Phonology
Sudanese Arabic
Syllabification
Phrasal Syllabification in Arabic
Prosodic domains of syllabification
Prosodic domains of syncope and epenthesis
Repairing Unsyllabified segments
Sudanese Arabic Stress

This study is a synchronic derivational analysis of phonological phenomena in three dialects of Sudanese Arabic. Its main goal is to provide a unified prosodic account of syncope and of the phonological processes functioning as strategies of repairing unsyllabified segments in the dialects of Urban Central Sudanese Arabic, Shukriiya, and Hamar. The domains of these processes are argued to follow from the degree of restriction that dialects place on word-level and phrase-level syllabification. To this end, the study proposes an analysis of syllabification in the three dialects that identifies the degree to which word-level syllabification is exhaustive, the segments that may be marked extrasyllabic and the conditions regulating their extrasyllabic status, the phrasal level at which these segments must be syllabified, and the level at which alteration to syllable structure is disallowed. In identifying the degrees of restriction dialects place on syllabification and resyllabification, the analysis provides a principled explanation for the levels of repair of unsyllabified segments as well as the domains of syncope. The study also provides an analysis of word stress and an analysis of phonological phrase formation. By revealing and accounting for the interesting phonological patterns attested in these dialects, the study aims to contribute to the area of Arabic phonology in general and to research on the typology of Arabic dialects in particular. In addition to the analyses proposed, its substantial contribution in this regard is a significant body of original data that is being analysed for the first time. With respect to dialects of Sudanese Arabic, the study represents a new direction of enquiry, one that seeks to disentangle their respective grammars and reveal the interesting ways in which they pattern alike and diverge.