VictorJuiz/thesis huggingface dataset:
The Molecular Composition of Soil Organic Matter (SOM) and Potential Responses to Global Warming and Elevated CO2

Soil organic matter (SOM) contains about twice the amount of carbon in the atmosphere. With global changes, the potential shifts in SOM quantity and quality are a major concern. Due to its heterogeneity, SOM remains largely unknown in terms of its molecular composition and responses to climatic events. Traditional bulk soil analysis cannot depict the structural changes in SOM. This thesis applies two complementary molecular-level methods, i.e., SOM biomarker gas chromatography/mass spectrometry (GC/MS) and nuclear magnetic resonance (NMR) spectroscopy, to examine the origin and degradation of various SOM components in grassland and temperate forest soils, and to investigate the shifts in microbial community and SOM composition with both laboratory- and field-simulated global changes, such as frequent freeze-thaw cycles, increasing soil temperatures, elevated atmospheric CO2 levels, and nitrogen (N) deposition. This thesis has several major findings. First, as the most active component in soil, microbial communities were sensitive to substrate availability changes resulting from prolonged soil incubation, freeze-thaw-induced cell lyses, N fertilization and increased plant inputs under elevated CO2 or soil warming. Microbial community shifts have direct impacts on SOM decomposition patterns. For instance, an increased fungal community was believed to contribute to the enhanced lignin oxidation in an in situ soil warming experiment as the primary degrader of lignin in terrestrial environments. Second, contrast to the conventional belief that aromatic structure was recalcitrant and stable in SOM, ester-bond aliphatic lipids primarily originating from plant cutin and suberin were preferentially preserved in the Canadian Prairie grassland soil profiles as compared with lignin-derived phenols. Cutin- and suberin-derived compounds also demonstrated higher stability during soil incubation. With an increased litter production under elevated CO2 or global warming, an enrichment of alkyl structures that had strong contributions from leaf cuticles was observed in the Duke Forest Free Air CO2 Enrichment (FACE) and soil warming experiments, suggesting an accumulation of plant-derived recalcitrant carbon in the soil. These results have significant implications for carbon sequestration and terrestrial biogeochemistry. Overall, this thesis represents the first of its kind to employ comprehensive molecular-level techniques in the investigation of SOM structural alterations under global changes.

Keywords: soil organic matter
climate change
biomarker
NMR
decomposition
recalcitrance
microbial PLFA
cutin
suberin
lignin
freeze-thaw cycle
global warming
N fertilization
FACE
Prairie grassland
temperate forest
fungi
bacteria
Advisor: Simpson, Myrna J.
Fundamental Investigation of Inkjet Deposition and Physical Immobilization of Horseradish Peroxidase on Cellulosic Substrates

In this study, novel bio-inks formulated with horseradish peroxidase, HRP, and some additives were successfully developed for piezoelectric inkjet application. The optimized bio-ink formulation had a reliable jetting performance and maintained the biofunctionality before and after printing. The bio-ink also demonstrated a good storage life for up to 40 days at 4 oC with a negligible loss of biofunctionality. However, it was observed that some additives used in the bio-ink for obtaining necessary operational characteristics had detrimental effects on the enzyme activity. Especially, it was found that various viscosity modifiers typically used in commercial inkjet inks significantly impaired HRP activity prior to printing. Sodium Carboxymethyl Cellulose was shown to be an effective viscosity modifier that had no adverse effect on the biological activity of the HRP enzyme. Using a confocal scanning fluorescent microscope, a method for characterizing the spatial distribution of the active enzyme within the cellulosic paper substrates after inkjet printing was developed. Interestingly, it was found that the active printed HRP enzyme was mostly located in the cell walls of the cellulosic fibers instead of near the pigments or fillers. In an effort to better understand the fundamental interactions between the enzyme and the immobilization substrates, HRP adsorption isotherms on various substrate surfaces were obtained using the depletion method. The substrates included not only pulp fibers with varying degree of hydrophobicity and pigment and latex (the key materials used in papermaking), but also other types of cellulosic fibers of different morphologies, crystallinities, porosities, or surface charge densities. The influence on enzyme adsorption and inactivation behaviour of these substrates was compared with that of polystyrene beads (dialysed), which has been well studied in the literature. Results from this thesis indicated that hydrophobic interactions between the enzyme and the substrate surfaces had a major impact on the HRP adsorption behavior, while electrostatic interactions played a minor role. However, strong hydrophobic interactions could lead to enzyme inactivation. Research findings from this study suggested that cellulosic pulp fibers could be tailor-made into excellent enzyme immobilization supports by using existing fiber surface modification techniques.

Keywords: bioactive paper
enzyme
cellulosic fibers
surface energy
Advisor: Yan, Ning
Molecular Rationale and Determinants of Sensitivity for Statin-Induced Apoptosis of Human Tumour Cells

The statin family of hydroxymethylglutaryl coenzyme A reductase (HMGCR) inhibitors, used to control hypercholesterolemia, triggers apoptosis of various human tumour cells. HMGCR is the rate-limiting enzyme of the mevalonate (MVA) pathway, a fundamental metabolic pathway required for the generation of a number of biochemical end-products including cholesterol and isoprenoids, but the contribution of the MVA pathway to human cancer remains largely unexplored. Furthermore, as only a subset of tumour cells has been shown to be highly responsive to statins, the identification of appropriate subsets of patients will be required to successfully advance these agents as anticancer therapeutics. To this end, there were two major aims to this work: 1) Elucidate a molecular rationale for the observed therapeutic index of statin-induced apoptosis in normal and tumour cells; 2) Identify molecular determinants of sensitivity for statin-induced apoptosis in human tumour cells. To address the first aim we demonstrated that dysregulation of the MVA pathway, achieved by ectopic expression of either full length HMGCR (HMGCR-FL) or its novel splice variant lacking exon 13 (HMGCR-D13), increases transformation. Ectopic HMGCR promotes growth of transformed and non-transformed cells under anchorage-independent conditions or as xenografts in immunocompromised mice. We also show that high mRNA levels of HMGCR and four out of five other MVA pathway genes correlate with poor prognosis in primary breast cancer, suggesting the MVA pathway may play a role in the etiology of human cancers. To address the second aim, we show that dysregulation of the MVA pathway is a key determinant of sensitivity to statin-induced apoptosis in multiple myeloma. In a panel of 17 distinct myeloma cell lines, half were sensitive to statin-induced apoptosis and the remainder were insensitive. Interestingly, in sensitive cells, the classic feedback response to statin exposure is lost, a feature we demonstrated could distinguish a subset of statin-sensitive primary myeloma cells. We further illustrated that statins are highly effective and well tolerated in an orthotopic model of myeloma using cells harboring a dysregulated MVA pathway. Taken together, this work provides a molecular rationale and determinants of sensitivity for statin-induced apoptosis of human tumour cells.

Keywords: statins
anti-cancer therapeutics
HMGCR
HMG-CoA reductase
ovarian cancer
multiple myeloma
apoptosis
drug sensitivity
drug resistance
mevalonate
transformation
tumour metabolism
Advisor: Penn, Linda Z.
Distorted Historical Fictions of the Holocaust, the Chilean Dictatorship, and the Algerian War of Independence

The desire and need for historical representation in postmodernism are coupled with the self-reflexive acknowledgement of our inability to faithfully represent the past. This dissertation examines the ways in which certain historical events are represented in postmodern fiction. More specifically, it introduces the term ‘distortion’ to designate various ways that postmodern authors have attempted to convey traumatic and violent histories through intentional permutations of historical facts. In this study, I analyse six texts, representative works that present the multi-faceted nature of what I call ‘distorted’ historical fiction. Each text is devoted to one of three historical events: the Holocaust in Martin Amis’s Time’s Arrow and Art Spiegelman’s Maus; the Chilean dictatorship in Diamela Eltit’s Lumpérica and Isabel Allende’s La Casa de los espíritus; and finally, the Algerian War of Independence in Kateb Yacine’s Nedjma and Mohammed Dib’s Qui se souvient de la mer. The analyses of each text are guided by three main questions: How is the depicted history distorted in the narrative? Why is the historical reality distorted? And lastly, what are the hermeneutical effects for the reader of engaging with the distorted historical text? I contend that these historical fictions apply various modes of distortion to create a specific and often peculiar effect on the reader. These include distortions of narrative form and voice, as well as distortions of temporality and space. I argue that the reader’s encounter with distorted historical fiction creates a peculiar hermeneutical effect of ‘defamiliarisation,’ which has affinities with Viktor Shklovsky’s use of the term and Bertolt Brecht’s ‘V-effekt.’ The sense of defamiliarisation creates a conflict in readers, in which their foreknowledge of a past event clashes with the event's distorted depiction. This conflict demands that the reader be responsible, implying that the reader should not be ‘swept away’ by the distorted narrative. Instead the responsible reader is encouraged to interact with the text, apply previous historical knowledge to correct said distortions, and through this interaction gain a greater intimacy with the past.

Keywords: hermeneutics
ethics
history
postmodernism
Chilean dictatorship
Algerian War of Independence
Holocaust
distortion
20th century literature
Advisor: Hutcheon, Linda
The Cuckold, His Wife, and Her Lover: A Study of Infidelity in the Cent nouvelles nouvelles, the Decameron, and the Libro de buen amor

This dissertation compares representations of women in erotic triangles. I contend that despite the stability implied by the triangular shape, the erotic triangle can be made unstable through women’s language. The first chapter examines medieval and contemporary writing on an essential relationship in the triangle: the friendship between the husband and the lover. Amicitia, chaste friendships between men, had its roots in Greek and Latin philosophy, and recently these relationships have been investigated according to mimetic desire (Girard) or homosocial desire (Sedgwick). In both medieval and modern configurations, these relationships are usually predicated upon the exchange of women. Claude Lévi-Strauss, Gayle Rubin and Luce Irigaray provide anthropological and literary explorations of the economic model where men exchange women to strengthen their homosocial bond. In the three texts, women use linguistic techniques to destabilize the erotic triangle. One is irony: frequently, one character does not understand an ironic statement and is excluded from the relationship between the other two participants. A second is pragmatic implicature, which is also used for exclusionary purposes. Other women adopt economic terminology to negotiate with their husbands or lovers for control of their bodies. Through these linguistic devices women speak exclusively to another member of the triangle, thereby undermining male friendships and denying their bodies be used as objects of exchange. Although their strategies are not always successful and some women remain exchangeable objects, we nevertheless see that erotic triangles can be destabilized. Furthermore, counter to the prevailing anthropological theory, certain women are aware of their position as commodities. From this insight, a new perspective on sexuality is exposed. The formerly strong male relationship, built on classical ideals and predicated on equality, breaks down when one man’s virility is pitted against his rival’s. Sometimes even, the supposedly chaste male relationship reveals erotic undertones. Women’s sexuality is also transformed when certain women prove to be desiring subjects, able to manipulate the system of exchange. In the end, institutionalized notions of chaste male friendships and women as objects of exchange are disrupted, sometimes even undermined, by capable women who determine who should have access to their bodies.

Keywords: Cent nouvelles nouvelles
Decameron
Libro de buen amor
Adultery
Infidelity
Advisor: Ross, Jill
The Material Culture of Women's Accessories: Middle-class Performance, Race Formation and Feminine Display, 1830-1920

This dissertation investigates the cultural meaning ascribed to feminine fashionable objects such as gloves, fans, parasols and vanity sets. I pay particular attention to issues of middle-class formation, the performance of gender, and the materiality of race, empire and colonialism. While these issues lie at the heart of British historiography, this project is written from a unique perspective which privileges cultural artifacts through material culture analysis. While the emergence of the middle class is typically studied as a masculine/public phenomenon, this project corrects the overemphasis on male activity by showing that middle-class women created a distinctive ‘look’ for their class via the consumption of specific goods and through participation in daily beauty rituals. Adding to these ideas, I argue that Victorian women performed a distinct type of femininity represented as passivity, asexuality, innocence, and leisure. By studying the repetitive gestures, poses and consumption practices of middle-class women, I show that certain corporeal acts helped to create Victorian femininity. This work also suggests that women participated in the British colonial project by consuming objects that were represented in the Victorian imagination as imperial spoils. As such, I argue that imperialism penetrated the everyday lives of Britons through several everyday objects. Empire building also created anxieties surrounding questions of race. Women’s accessories, such as gloves and parasols, helped British women to maintain their whiteness, an important way of distinguishing the ‘civilized’ Britons from the ‘uncivilized’ tanned colonial peoples. Overall this project showed that within the everyday objects consumed by women we can identify the anxieties, hopes and dreams of Victorians.

Keywords: women
material culture
accessories
fashion
gender
identity
race
class
Advisor: Loeb, Lori
Teacher Learning Made Visible: Collaboration and the Study of Pedagogical Documentation in Two Childcare Centres

Pedagogical documentation inspired by the early childhood schools of Reggio Emilia, Italy is a tool for teacher inquiry, learning, and development. Teachers systematically reflect upon artifacts that make visible children’s thinking, using for instance, digital photographs, quotations of children’s verbal thoughts, and teachers’ field notes. In two Reggio-inspired childcare centres in Toronto, Ontario, Canada, early childhood educators formed two teacher learning groups to study pedagogical documentation. As participants studied these artifacts (i.e. documentation), an underlying question emerges: What happens to teacher learning when early childhood educators form teacher learning groups to study pedagogical documentation in childcare centres? From this question, participants collaborated throughout six to seven research meetings to discuss and reflect upon documentation that they created. Portraiture research as a method of qualitative inquiry (Lawrence-Lightfoot, 1983; Lawrence-Lightfoot & Davis, 1997) offered a range of data collection methods used in this study, including videotaped research meetings, participants’ documentation work, open-ended group interview, and researcher’s field notes. These methods informed the portraiture research and constructed a vivid, in-depth look at participants’ experiences in studying pedagogical documentation in teacher learning groups. The results of this study are retold through two portraits focusing on the co-construction of teacher knowledge in teacher learning groups. Participants’ experiences such as deconstructing barriers to documentation practice, developing new documentation skills, critical self-reflection upon teacher practice, and emergent curriculum planning generated two rich portraits of teacher learning and development. Essential themes, conclusions, and implications appear in the examination of the two portraits and are explored in the final chapter. The themes included: (1) Skills of documentation, (2) Teacher learning and, (3) Teacher collaboration. Overall, this research study exposed the questions and assumptions, process of inquires, and new teacher knowledges and practices developed by two groups of early childhood educators in this study.

Keywords: teacher learning
professional development
social constructivism
teacher learning groups
early childhood education
Reggio Emilia approach
pedagogical documentation
Advisor: Kooy, Mary
Cataloguing Wilderness: Whiteness, Masculinity and Responsible Citizenship in Canadian Outdoor Recreation Texts

This research examines representations of wilderness, Canadian nationalism and the production of responsible and respectable subjects in commonplace outdoor recreation texts from Mountain Equipment Co-op, the Bruce Trail Conservancy and the Bruce Peninsula National Park. Drawing theoretical insights from Foucault’s genealogy and technologies of the self, post-structural feminism and anti-racist scholarship on whiteness, I pose three broad questions: How is nature understood? How is Canada imagined? How are certain subjects produced through outdoor recreation? In this research, I outline five ways in which wilderness is represented. First, I consider how wilderness is produced as a place that is above all else empty (of human inhabitants and human presence). I then examine four ways in which the empty wilderness is represented: first, as dangerous and inhospitable, second, as threatened, third, as sublime and fourth, as the Canadian nation. I link the meanings invested into wilderness with a set of practices or desired forms of conduct in order to articulate how a specific subject is produced. These subjects draw on the meanings attributed to wilderness. The dangerous wilderness can only be navigated by a Calculating Adventurer. The threatened wilderness desperately needs the assistance of the Conscientious Consumer. The sublime wilderness provides respite for the Transformed Traveler. The Canadian or national wilderness is best suited to and belongs to the Wilderness Citizen. The four subjects I examine in this thesis each draw from particular wilderness representations and specific practices in order to be produced as desirable in the context of outdoor recreation. By examining the relationship between wilderness discourse, subjects and practices in everyday texts, I illustrate how masculine and white respectability operate in outdoor recreation. Pointing to subtle shifts in the meanings and values attributed to masculinity, Canadianness and whiteness, I articulate how outdoor recreation texts produce subject positions which are richly embedded in race and gender privilege and assertions about national belonging. In addition to examining whiteness, nationalism and masculinity, this research examines how individualized practices, such as consumer activism, become understood as the conduct of responsible neoliberal citizens concerned with national and environmental interests.

Keywords: whiteness
Foucault
outdoor recreation
masculinity
representation
Canadian nationalism
self governance
consumption
wilderness
Advisor: Dehli, Kari
Old Coyotes: Life Histories of Aging Gay Men in Rural Canada

Current understandings of aging and the life course are largely based on taken-for-granted hetero-normative assumptions. Gay men lack aging road maps that are unique to their life course experiences and which consider the changing contextual and social conditions that shape their participation choices in family and community roles. This is particularly so for gay men aging in rural environments as most studies of aging gay men focus on the urban experience. This study adds to understandings of aging and the life course by examining the lives of three gay men aging in rural environments. I use a life history approach to shed light on how sexual identity development and marginalization within rural environments intersect with shifting social contexts to shape the aging process in terms of engagement in social role opportunities, namely, community and family participation. As a life course researcher, I pay particular attention to the tensions between individual agency and structural constraints and how they are revealed through the life histories. Epistemological and methodological assumptions based on social constructivism, critical and queer theory inform the study while my own lived experiences as a gay man and an occupational therapist practitioner and educator ground the study. Cross-cutting themes identified in the life narratives reveal connections between sexual identity development and the coming out processes with patterns of social relationships and the gay aging process. These themes are then discussed in terms of their relevance to broader aging and life course constructs including generativity, social capital and gay aging; agency and structure in identity development; and expanded notions of family and social support for gay men. Findings from this study have implications for current explanations of ageing and life course processes; challenge limiting stereotypes of older gay men; inform health and social service professionals who work with older gay people; and provide examples of alternative queer life pathways for gay people of all ages.

Keywords: gay aging and the life course
gay aging in rural Canada
occupational aging
life history methodology
Advisor: Cole, Ardra