VictorJuiz/thesis huggingface dataset:
Interface Properties of the Amorphous Silicon/Crystalline Silicon Heterojunction photovoltaic cell

Amorphous-crystalline silicon (a-Si:H/c-Si) heterojunctions have the potential of being a very high efficiency silicon photovoltaic platform technology with accompanying cost and energy budget reductions. In this research a heterojunction cell structure based on a-Si:H deposited using a DC saddle field plasma enhanced vapour deposition (DCSF PECVD) technique is studied, and the a-Si:H/c-Si and indium tin oxide/a-Si:H interfaces are examined using several characterization methods.Photocarrier radiometry (PCR) is used for the first time to probe the a-Si:H/c-Si junction. PCR is demonstrated as a carrier lifetime measurement technique - specifically, confirming carrier lifetimes above 1 ms for 1-5 Ohm.cm phosphorous-doped c-Si wafers passivated on both sides with 30 nm of i-a-Si:H. PCR is also used to determine surface recombination velocity and mobility, and to probe recombination at the a-Si:H/c-Si interface, distinguishing interface recombination from recombination within the a-Si:H layer or at the a-Si:H surface.A complementary technique, lateral conductivity is applied over a temperature range of 140 K to 430 K to construct energy band diagrams of a-Si:H/c-Si junctions. Boron doped a-Si:H films on glass are shown to have activation energies of 0.3 to 0.35 eV, tuneable by adjusting the diborane to silane gas ratio during deposition. Heterojunction samples show evidence of a strong hole inversion layer and a valence band offset of approximately 0.4 eV; carrier concentration in the inversion layer is reduced in p-a-Si:H/i-a-Si:H/c-Si structures as intrinsic layer thickness increases, while carrier lifetime is increased.The indium tin oxide/amorphous silicon interface is also examined. Optimal ITO films were prepared with a sheet resistance of 17.3 Ohm/square and AM1.5 averaged transmittance of 92.1%., for a film thickness of approximately 85 nm, using temperatures below 200 degrees celcius. Two different heat treatments are found to cause crystallization of ITO and to change the properties of the underlying a-Si:H film.Finally, an open circuit voltage of 699 mV was achieved using DCSF PECVD in the tetrode configuration to fabricate a metal/ITO/p-a-Si:H/i-a-Si:H/n-c-Si/i-a-Si:H/n+-a-Si:H/metal photovoltaic cell on a texturized wafer. The 4 cm2 cell had an efficiency of 16.5%, a short circuit current of 36.4 mA/cm2 and a fill factor of 64.7%.

Keywords: amorphous silicon
crystalline silicon
heterojunction
passivation
photocarrier radiometry
photovoltaics
Advisor: Kherani, Nazir P
Essays on Market Conditions and Corporate Investment Decisions

This thesis investigates how market conditions -- different beliefs about firm value, the business cycle, and financial regulations -- affect corporate investment decisions in firms, and the impact of these decisions on corporate performance. In Chapter 1, I document evidence that belief dispersion affects corporate investment allocation. When investors disagree with each other on expectations about future project returns, firms allocate a larger share of total investment in riskier projects (for example, R and M), in order to exploit the disagreement, and they allocate less in physical capital investment. This effect becomes amplified when firms experience a positive return shock to CAPX, when more investment in CAPX would be expected. To establish causality, I use mergers between brokerage houses to provide a source of exogenous shocks to belief dispersion. Chapter 2, written jointly with Mohammad Rahaman, uses economic recessions as settings for `creative destruction' and examines the efficiency of pro-cyclical capital reallocation through the corporate-control market. It shows that the efficacy of M investment activities varies with time and in intensity, as firms that concentrate most of their M activities in the good times are more likely to exit inefficiently in a subsequent recession. The results suggest that firms misallocate capital through excessive M\ during expansions, thus becoming more vulnerable when there is a negative aggregate shock. Chapter 3, written jointly with Varouj Aivazian and Mohammad Rahaman, provides cross-country evidence to show that adverse financial shocks to firms can be attenuated through regulations. Episodes of systemic banking crises across many countries are examined to identify unanticipated credit contractions; firm investment growth during and post crisis periods are compared to their pre-crisis levels. The chapter shows that credit contractions are costly for firms, and that they are more costly for firms that are more reliant on the external capital market. It is also shown that declines in investment growth are greater for externally dependent firms if such firms are embedded in ex-ante ``repressively" regulated financial markets. The results suggest that specific financial reforms play a significant role in attenuating the propagation of a banking crisis to the real sector.

Keywords: Corporate Fiannce
Corporate Investment
Financial Regulations
Investment Allocation
Investor Belief Dispersion
M
Advisor: Zhu, Xiaodong
Aivazian, Varouj A
Diverging and Contested Feminisms in Early Social Work History in Ontario (1900-1950)

AbstractThis study examines early Ontario social work history by documenting the lives of four women who contributed to the history of Ontario social work some of whom have largely been forgotten. While social work remains a female-dominated profession, both currently and historically, few historical studies have addressed this. This study attempts to equalize the views and voices of social workers by including select women who were active in the field illuminating and identifying some of the contributions of women to the debates which characterized early social work in Ontario. This study selected two women from the radical tradition with socialist/communist affiliations and as counterpoint two figures who were members of the Imperial Order of the Daughters of the Empire and who represent a conservative value system based in the tradition of British imperialism. Three guiding research questions for the study are 1) what conditions organizations and practices shaped and positioned social work as a profession in its formative years 2) how were the significant debates/discursive trajectories reflected in the organizational settings of early social work? 3) How were these ideas implicated in their practice? Did these women speak through the organizations they led or participated in? How did they contribute to the production of or alternative positions to, the competing epistemĂŠs of the time? This research provides an original contribution by elaborating a history of ideas in social work through the prism of organizational practice and key formative figures. By adopting this dual focus, I capture individual agency in life history but also the cultural shift of discourse and regimes of truth, not only within individual lives but also as a myriad of intersecting overlapping discursive (ideas) and material (practices) occurrences.

Keywords: Canadian history
Canadian social work
feminist history
imperialism
postcolonial feminist history
socialist feminism
Advisor: Chambon, Adrienne S
MicroRNAs in the Regulation of Cellular Stress Responses

MicroRNAs are key regulators of cellular functions at post-transcriptional level. There is an emerging concept that microRNAs are involved in the regulation of how cells respond to changes in environment and stress conditions. Understanding the consequence of microRNA regulatory network has the potential to answer a multitude of fundamental questions. Dysregulation of these processes is associated with cancer development and drug resistance. In this dissertation, four studies are presented. The first study demonstrated that microRNA-17 targets both oncogene MDM2 and tumor suppressor gene PTEN: it suppresses glioblastoma tumor cell proliferation in favorable condition. However, when challenged by starvation or chemotherapy, it induced angiogenesis and the generation of tumor stem-like cells, and helping tumor cells survive in metabolic stress. The second study revealed the role of microRNA-17 in the regulation of chemotherapy sensitivity. By analyzing tissue samples from colorectal cancer patients, we found that microRNA-17 serves as a predictive factor of chemotherapy and prognostic factor of overall survival. Overexpression of microRNA-17 in colorectal cancer cells increased drug resistance and cell motility. The third study focused on the impact of microRNA on antitumor immune response. We found vigorous anti-melanoma immune response in microRNA-17 transgenic mice, which is characterized by CD8+ T lymphocytes infiltration. We further demonstrated the potential role of microRNA in the coordination of interaction between tumor cells and microenvironment. The fourth study examined the function of microRNA in tissue regeneration. We found an enhanced wound healing process in anti-microRNA-378 transgenic mice that have otherwise normal phenotype. Knocking down microRNA increased the expression of its targets Vimentin and Integrin beta-3, helping wound healing. Conjugated gold nanoparticle treatment delivered antisense oligos to the wound area and achieved therapeutic effect. Taken together, these studies illustrate the multiplicity of microRNA in the coordination of cellular stress responses.

Keywords: Cancer
Chemotherapy
Homeostasis
Metastasis
microRNA
Stress
Advisor: Yang, Burton B
Impact of Mandatory Changes in Convertible Debt Accounting: Evidence from APB 14-1

Using a set of hand-collected data, I study the economic consequences of APB 14-1 adopted in 2008, which requires that issuers of cash-settled convertible debt divide the total proceeds from the issuance into liability and equity components ("bifurcation"). First, I find that issuers are more likely to reduce the outstanding amount of cash-settled convertible debt when the increase (decrease) in interest expense (leverage ratio) resulting from the bifurcation process is higher (lower). The probability of early repurchase is higher when mandatory accounting changes are included in the calculation of debt covenant compliance. This finding is consistent with the debt contracting hypothesis that APB 14-1 increases the probability of debt covenant violations. Next, I examine whether credit rating agencies evaluate the issuers' accounting information differently after the adoption of APB 14-1. I find that the financial ratios in the post-2008 period, such as interest coverage ratios and leverage ratios, can better explain the issuers' credit ratings than those in the pre-2008 period. Lastly, I find that shareholders of cash-settled convertible bond issuers experience an overall loss of wealth of 2.1% associated with APB 14-1. The negative shareholder reactions are greater when issuers use rolling GAAP in their bank loan agreements to calculate debt covenant compliance. These empirical results are consistent with the notion that mandatory changes in financial reporting of cash-settled convertible debt have real effects on managerial behavior and the usefulness of information from financial statements used by the credit market.

Keywords: Convertible debt
Credit ratings
Debt contract
Economic consequences of accounting standard
Shareholder wealth effects
Advisor: Richardson, Gordon D.
DeFranco, Gus
Immigrant Women and their Work in the Informal Economy in Toronto: Impacts and the Potential for Critical Transformations

This research examines the everyday experiences of immigrant women working informally in the City of Toronto (Canada). The study is based on analysis of original in depth interview (n = 27) and focus group data (n = 19). The thesis begins from the belief that the choice of highly educated immigrant women, with and without professional work experiences from their home countries, to do informal work in Canada is part of a fact that they are going through a particularly intensive process of change. With special attention to the potential for critical transformative learning (e.g. Mezirow; Freire) - how this change is produced, experienced, and addressed is the key focus in this study. The study considers three avenues of experience potentially influencing change in the lives of immigrant women post-immigration: i) the ways of knowing, frames of reference, and worldviews of these women as shaped by the complex relationship between their private (e.g. as mothers and wives) and public (e.g. as community members and informal product/service workers) lives; ii) the various economic and cultural relations and shifting locations that mediate how the individual makes choices regarding (formal and/or informal) work activities; and, iii) the social relations shaping the changing experiences and interpretations of interlocking systems of power relations involving gender, race, class and disability.Agentive participation and learning in the context of economic participation are key in understanding women's choices, experiences, and outcomes in the context of their work and life experiences in Canada. This study reveals the multidimensional, often contradictory, processes of change that individuals in marginalized situations post-immigration go through and their awareness of and influence over these change processes. The analysis suggests a multilayered process that supports and sometimes inhibits the creation of a new foundation for various types of transformative learning trajectories; one that keeps the loose threads together and moves people towards and along a path they individually or collectively choose to follow in order to find meaning and realize positive change.

Keywords: immigrant women
informal economy
learning
social relations
transformation
Advisor: Sawchuk, Peter
"Sophisticated Laddie:" Scottish Flute Music 1720-80 on a Stylistic Continuum

Eighteenth-century Scottish repertoire for flute has remained separate from mainstream continental flute music for both performance and study, and as a result, is not well known. This music, written in an environment where Scotsmen embraced nationalist pride and their Scottish identity, offers flutists insight into a unique repertoire that often carries distinct Scottish inflection. This study examines music for flute written by Scottish composers from 1720-80, identifying distinctive elements of style, and presents a view of the music on a stylistic continuum that demonstrates a blend of continental concert and Scottish traditional elements. Repertoire written by James Oswald, William McGibbon, Alexander Munro, General John Reid and Charles McLean serves as the main focus for examination. Placing this music in historical and musical context, the study synthesizes existing scholarship by Matthew Gelbart, Robert Gjerdingen and David Johnson with other research, to draw new connections to Italianate compositional practices and elements of Scottish traditional music performance practice. These new perspectives on Scottish flute literature can serve as a complement to the body of existing research of continental flute music performance practice.

Keywords: eighteenth-century
Flute
Performance Practice
Scottish
traditional
Advisor: Elliott, Robin
Functional Analysis of the Anorexia Mouse Mutation

The serotenergic and hypothalamic systems regulate mood and food intake, respectively, which can both be altered in neurodegenerative and psychiatric disorders. The spontaneous recessive anorexia (anx) mouse mutation has previously been shown to cause widespread deficits in serotonergic innervation, and more recently, hypothalamic neuronal degeneration. These neuronal deficits observed in anx/anx mice contribute to their emaciated appearance and abnormal behaviours. The anx mutation is located on mouse chromosome 2 in an interval syntenic to human 15q22, which has been linked with catatonic schizophrenia and cases of autism and phobic disorders. At present, while the mutation(s) causative of the anx phenotype remains unknown, I have further characterized a novel neurodegeneration phenotype in anx/anx brains. In addition, we have identified a genetic variant that contributes to the anx phenotype. To test the effects of the genetic variant, we generated normal and mutant transgenic mouse lines. The normal line resulted in the partial rescue of anx phenotypes. Conversely, the mutant line showed no rescue. Thus, we have identified the first genetic modifier of the anx phenotype. Given the neurobiological effects of the anx mutation coupled with its intriguing genetic location, further examining the anx mutation may contribute to a better understanding of human psychiatric and neurodegenerative disorders.

Keywords: Mouse genetics
Molecular Biology
Advisor: Cordes, Sabine
The Concept of Evidence in Health Technology Assessment (HTA)

This dissertation aims to make four contributions to knowledge. First, unlike other fields (e.g. science, medicine, etc.), the field of health technology assessment (HTA), has not thus far greatly benefited from a conceptually rigorous, philosophical analysis. Thus, the overall, and first, contribution of this dissertation is to begin to fill in some of this gap. Second, because cross-jurisdictional comparisons and analyses are uncommon in the HTA literature, the dissertation devises a heuristically useful scheme for this purpose, and subsequently utilises that scheme to compare Canada’s, Australia’s and UK’s approaches to HTA at the national level (focusing on CADTH, MSAC and NIHR, respectively). This analysis reveals that although HTA is claimed to be an evidence-based endeavour, the agencies’ assessments rely on a variety of probative inputs, raising the question of how, exactly, these bodies understand the concept of ‘evidence’? An analysis of the HTA literature, as well as of the publications of the HTA agencies themselves, reveals that HTA, unlike other evidence based fields (such as evidence-based medicine (EBM) and evidence-based health policy (EBHP)), has thus far failed to flesh out an account of evidence. Thus, as a third contribution to knowledge, an account of evidence that is suitable for HTA purposes is proposed here. Evidence is argued to be: available data that is relevant to the issue being addressed, question asked, decision made, etc. It is further argued that this definition enjoys numerous benefits, whilst simultaneously bypassing some of the problems around the definitions of evidence proposed in the EBM and EBHP literature. The tenability and utility of the proposed definition is tested twice. First, the definition is tested against CADTH’s, MSAC’s and NIHR’s evaluative practices vis-à-vis health technologies in general, and second, the definition is tested against the agencies’ evaluative practices vis-à-vis genetic tests in particular. Thus, as a fourth contribution, the dissertation addresses genetic tests as an HTA issue, rather than as a bioethics issue, as it is predominantly done in the literature. In case of both the assessments of health technologies generally speaking, and assessments of genetic tests in particular, it is argued that the proposed definition of evidence is both tenable and useful, as it captures all and only the probative inputs that are required by the health technological assessments.

Keywords: Health technology assessment
HTA
Evidence
Health policy
Advisor: Castle, David
Genetic-epigenetic Interactions: Sequence-dependent and Independent DNA Nethylation

The field of human epigenetics has become widely accepted, yet many basic principles remain unclear. It is important to determine the extent to which DNA methylation profiles are influenced by DNA sequence; we addressed this question using tissues from human monozygotic (MZ) and dizygotic (DZ) twins, post-mortem brain and germline samples. First, we analyzed white blood cells (WBC), buccal epithelium, and rectal biopsies from MZ twins, and annotated the epigenetic metastability of ~6,000 unique genomic regions. Our study was the first to utilize epigenome-wide profiling to document DNA methylation differences in MZ twins. We also found that DZ twins exhibited more epigenetic differences compared to MZ twins. Two competing hypotheses were tested: 1) DNA sequence differences caused the additional DZ epigenetic variation, or 2) additional epigenetic differences are present in the zygotes of DZ co-twins. Our animal and in silico studies supported hypothesis 2, providing the first evidence for twin-based epigenetic heritability. Still, genetic impact on epigenetic variation cannot be excluded. To explore DNA–epigenetic interactions and their role in disease, we mapped allele-specific methylation (ASM) in brain and sperm DNA from individuals affected with major psychosis and controls. We found that ~2.5% of brain SNPs show ASM, although genomic distribution of these “epiSNPs” varies between cohorts. EpiSNPs were generally enriched in untranslated regions (UTRs) and regions surrounding genes, and depleted in exons. The schizophrenia cohort contained twice as many epiSNPs as controls and bipolar disorder, although they largely overlapped. Most epiSNP Gene Ontology categories were related to brain development and function; differences between cohorts were observed in glutamate and insulin pathways. Tissue-specific epiSNPs were also detected in sperm DNA. Deep sequencing analysis revealed that any SNP could potentially demonstrate low-level ASM. This work describes various aspects of genetic–epigenetic interactions, while supporting epigenetic heritability and the role of genetic-epigenetic interactions in major psychiatric disease.

Keywords: epigenetics
genetics
twins
DNA methylation
microarray
allele-specific methylation
major psychosis
epigenetic inheritance
Advisor: Petronis, Arturas