VictorJuiz/thesis huggingface dataset:
Dynamics of dry friction damped systems subjected to multi-frequency excitations

This thesis is devoted to the nonlinear vibration analysis of mechanical systems subjected to both dry friction and multi-frequency excitations, with emphasis laid on analyzing the effects of the dry friction and the multi-frequency excitations on the system's dynamic characteristics. Various types of steady-state motions the systems may experience are analyzed in the thesis, including periodic, quasi-periodic and chaotic motions. The systems investigated contain those of single-degree-of-freedom (single DOF) as well as the multi-degree-of-freedom (multi-DOF) systems. First, single-degree-of-freedom systems are studied. The nonstick and stick-slip periodic responses are derived analytically for a single DOF dry friction oscillator with two-frequency excitations. Furthermore, the dynamics of a single-degree-of-freedom dry friction damped block-on-belt system under two-frequency excitations is studied with bifurcation analysis as well as analysis of Poincare sections and Lyapunov exponents. Two types of system models are investigated: one is excited by two external forces whereas the other is excited both externally and parametrically. Both systems possess rich dynamic behavior characterized by periodic, quasi-periodic and chaotic attractors. As for the multi-degree-of-freedom systems, the rotational vibration of a belt drive system with a Coulomb-damped tensioner and subjected to multi-frequency excitations is studied, with an analytical method presented for the first time. Two kinds of periodic responses of the system characterized by the nonstick and stick-slip motions of the tensioner arm are obtained analytically. The impacts of the tensioner dry friction and the excitation frequencies on the dynamic behavior of the system are illustrated via evaluating the frequency responses of a prototypical belt drive. Besides, the dynamics of a multi-DOF system with simultaneous Coulomb friction and multi-frequency excitations is studied. An original two-dimensional map is proposed, which reduces the system without losing its essential dynamic features and greatly simplifies the investigation.
Spinning transnational webs: Ethnic entrepreneurship and social networks in the Internet age

Research on transnational entrepreneurship has emerged since the 1990s. Although social networks have been theorized as the foundation of the transnational social field and the use of new technologies as the key characteristic that distinguishes contemporary transnational practices from historical ones, few studies have explored the relation of networks and Internet use to transnational entrepreneurship. Keyword: Social networks, economic sociology, entrepreneurship, transnationalism, international migration, race and ethnicity, technology and societyIntegrating three sets of literature: economic sociology, social network analysis, and technology and society, this dissertation examines how factors at the macro, meso, and micro levels facilitate or constrain Chinese Canadians' participation in transnational entrepreneurship. Using mixed methods, data were collected through ethnographic study, in-depth interviews, and a random sample survey. Results show that more than 40% of Chinese Canadian entrepreneurs are transnational. The opportunity structure shaped by Canada's immigration policies and China's national strategy of recruiting Overseas Chinese for economic development sets the stage for transnational entrepreneurship. Analyzing the various aspects of networks and Internet use, this dissertation reveals that transnational entrepreneurship is embedded in glocalized networks and facilitated by new communication technologies. Exploring how entrepreneurs cultivate networks, this research contributes to the entrepreneurship literature and social network analysis. Examining immigrant networks beyond the enclaves, this research advances the literature on ethnic economy and entrepreneurship. The significance of glocalized networks makes a strong case that ethnic entrepreneurship is not enclave bounded - spatially or socially. Moreover, this research contributes to the literature on technology and society by revealing both the possibilities and limitations of the Internet for building networks and participating in transnational entrepreneurship. These findings have policy implications for immigrant integration, entrepreneurship, and international trade.
Regulation of expression of CD200 in vitro

CD200 is a type I membrane glycoprotein and belongs to the immunoglobulin supergene family. CD200 delivers immunoregulatory signals through interaction with its receptors. Expression levels of the molecule regulate graft survival, susceptibility to autoimmune diseases, fetal loss, inflammation/infection and tumor rejection. Thus, exploration of the mechanism(s) controlling CD200 expression may provide insight into novel strategies for treatment of clinical disorders.

Keywords: Molecular biology
Genetics
Immunology
A novel polymorphism in ANKH is associated with ankylosing spondylitis

Ankylosing spondylitis (AS) is an inflammatory disease involving new bone formation in the sacroiliac joint and spine. HLA-B27 is a major genetic contributor to disease susceptibility; however, the concordance rates in twins indicate that there are other contributing factors, both genetic and non-genetic. ANKH is the human homolog of the mouse ank gene, in which a nonsense mutation causes progressive ankylosis similar to human AS. Other work in our laboratory showed that the ANKH region is significantly linked to AS. In this study, I performed a family-based association study which showed that a specific polymorphism in the 5 ′-noncoding region of ANKH is significantly associated with AS.
Credit barrier models

The thesis contains the construction of a new class of pricing models for credit derivatives. The underlying stochastic process models the credit quality of individual obligors within the wider context of all firms that issue debt. The challenge is to reconcile a broad set of statistical and pricing information within a model where the main observables can be computed as integrals or sums of well-known functions, and the other observables are obtainable through efficient numerical schemes. Lastly, we give applications of this credit model. Risk-neutral transition probabilities are calculated and compared with those calculated using previous models. Credit default swaps are priced. A mapping to equity in which the equity process is a martingale is constructed. This mapping to equity allows us to price, in particular, equity default swaps. Empirical results from the mapping indicate that the constant elasticity of variance (CEV) process would be an appropriate pure diffusion approximation to our process to price equity default swaps, and results using the CEV process are presented. In the first part, we use continuous processes that are based on square-root diffusion processes. Parameterized local volatility is introduced by a measure change and a coordinate transformation in such a way that the stochastic process retains integrability. Jumps in the process are introduced by subordinating on a random time-change. With this framework we are able to match empirical data on credit processes. Adding a drift enables us to introduce a measure change to the pricing measure to achieve consistency with market prices. In the second part, we discretise the stochastic process in such a way that node-to-node transition probabilities can be computed as sums of orthogonal polynomials. In this way, computing efficiency is increased while the empirical properties of the model remain intact.
Caenorhabditis elegans [beta]1,2 N-acetylglucosaminyltransferase I (GnT I) genes and functions

UDP-N-acetylglucosamine:α-3-D-mannoside β-1,2- N-acetylglucosaminyltransferase I (GnT I) is a key enzyme in the synthesis of Asn-linked complex and hybrid glycans. Studies on mice with a null mutation in the GnT I gene have indicated that N-glycans play critical roles in mammalian morphogenesis. This thesis presents studies on N-glycans during the development of the nematode Caenorhabditis elegans. We have cloned cDNAs for three predicted C. elegans genes homologous to mammalian GnT I (designated gly-12, gly-13 and gly-14). All three cDNAs encode proteins (467, 449 and 437 amino acids, respectively) with the domain structure typical of previously cloned Golgi-type glycosyltransferases. Expression in transgenic worms showed that they all encode active GnT I. GLY-13 is unique in that it only utilizes the physiological Man5GlcNAc2− as sugar acceptor. All three genes were expressed throughout worm development (embryo, larval stages L1 to L4 and adult worms). Experiments with lacZ reporter transgenes indicated that gly-12 and gly-13 promoters were expressed from embryogenesis to adulthood in many tissues. The gly-14 reporter was expressed only in gut cells from L1 to adult developmental stages. To better understand the role of complex N-glycans in C. elegans development, I isolated mutants lacking these three genes by the method of UV irradiation in the presence of trimethylpsoralen (TMP). These mutations are intragene deletions, removing large portions of the GnT I catalytic domain. Therefore they all are molecular nulls. I have characterized the gly-12 and gly-14 mutants as well as the gly-14; gly-12 double mutant. These mutants displayed wild-type phenotypes, indicating that neither gly-12 nor gly-14 is necessary for worm to develop under standard laboratory conditions. In contrast, the mutant lacking gly-13 gene displayed severe morphological and behavioural defects despite the presence of the other two GnT I genes, gly-12 and gly-14. I have shown that the observed phenotypes co-segregated with the gly-13 deletion in the genetic mapping experiments. However, I was unable to correct the phenotypes by transgene rescue approaches. Isolation of a second gly-13 null allele would provide an alternative means of verifying the requirement for gly-13. In conclusion, I have shown that all three C. elegans genes encode active GnT I, and they are expressed throughout development. Studies on the “knock-out” mutants revealed that hybrid and complex N-glycans are probably essential for the normal development of C. elegans, as they are for mammals.
Constitutively expressed heat shock proteins in the rat nervous system

The induction of heat shock proteins (Hsps) has been established as a characteristic feature of the heat shock response. Some Hsps are constitutively expressed in non-stressed cells. Constitutive Hsps may be of particular importance in the mammalian nervous system because of their higher expression levels in the neural tissues than other tissues. In this thesis, we examined the expression levels of constitutive Hsps in different classes of neurons, and investigated the involvement of Hsc70 in the neuronal heat shock response. Quantitative immunohistochemistry analysis revealed differing expression levels of constitutive Hsc70 and Hsp27 in different populations of neurons. Motor neurons in the spinal cord showed high levels of Hsc70 compared to dopaminergic neurons of the substantia nigra while neurons in the entorhinal cortex and hippocampus demonstrate even lower levels of Hsc70. Hsp27 was constitutively expressed at high levels in motor neurons of the spinal cord but was not detectable in neurons of the entorhinal cortex, hippocampus and substantia nigra. Other constitutively expressed Hsps, such as Hsp110, Hsp90, Hsp60 and Hsp40, did not demonstrate significant differences in levels in the various classes of neurons. The widely differing levels of constitutive Hsc70 and Hsp27 in different classes of neurons may have implications in neurodegenerative diseases. Neural cell types showing high levels of Hsc70 and Hsp27 may have a high buffering capacity against protein misfolding disorders. Following thermal stress, Hsc70 demonstrated a translocation to synapse-enriched areas of the cerebral cortex where it associated with Hsp40 to form a complex that can refold denatured proteins. The induction of Hsp70 was mainly observed in glial cells. Our results suggest that the heat shock response in the nervous system involves not only the synthesis of stress-inducible Hsps but also the redeployment of constitutively expressed Hsc70 to the synapse-enriched areas. Lipid rafts are an important compartment of synapses and platforms for signal transduction complexes involved in neurotransmission events. A set of constitutive Hsps was associated with lipid rafts and did not show major changes following thermal stress, suggesting that they may play roles in maintaining the stability of lipid raft-associated signal transduction complexes following neural stress.
Virulence mechanisms of mycobacteria - New insights from studies of BCG vaccine strains and cell wall biosynthesis

Virulence mechanisms of Mycobacterium tuberculosis remain largely unknown. Currently, only two well-established virulence determinants have been identified: the RD1 protein secretion system and the cell wall lipids. Studies of RD1 secretion system originated from the observation that the RD1 locus is deleted in all strains of Mycobacterium bovis Bacillus Calmette--Guerin (BCG), an attenuated, live vaccine that has been used in humans since 1920s. However, reintroduction of RD1 into BCG does not restore full virulence to BCG; therefore other mechanisms exist to fully account for the attenuation of BCG. The mycobacterial cell wall is a unique and complex structure that distinguishes mycobacteria from other bacteria. Although not fully understood, there is increasing evidence that the complex cell wall plays a major role in the virulence and pathogenesis of M. tuberculosis. However, the genetic and biochemical pathways leading to the biosynthesis of individual cell wall lipids remain incompletely understood. My thesis consists of two parts. In the first part, I describe the metabolic deficiency of BCG vaccine strains. I show that BCG exhibits dysregulation of glutamine synthetase, a key enzyme in nitrogen metabolism. This defect, together with mutations that affect the production (e.g., alanine dehydrogenase) or the expression (e.g., serine deaminase) of catabolic enzymes renders BCG with deficient growth under nitrogen-limited conditions in vitro, which may also contribute to the attenuation of BCG in vivo. These findings shed new light into the mechanisms of attenuation of BCG. The second part of my thesis deals with cell wall biosynthesis. I observed that some BCG strains cannot synthesize the virulence lipids phthiocerol dimycocerosates and phenolic glycolipids, providing an explanation for heterogeneity in residual BCG virulence and reactogenicity. I have also identified Lsr2, a previously uncharacterized protein found in all mycobacteria, as a novel regulator of lipid biosynthesis. Characterization of the Lsr2 protein revealed DNA-bridging properties functionally analogous to H-NS, a bacterial nucleoid associated protein. And like H-NS, Lsr2 likely functions as a global repressor for a number of genes including those involved in virulence. This finding opens new avenues for identifying novel virulence genes in M. tuberculosis.

Keywords: Genetics
Microbiology
Biochemistry
Analysis of Saccharomyces cerevisiae cyclin dependent kinase inhibitor Far1

In budding yeast, mating pheromone induces G1 arrest and prepares cells for conjugation. It's believed that phosphorylation of Far1, a protein required for mating-induced cell cycle arrest, by the pheromone-stimulated MAPK Fus3 enhances the binding of Far1 to G1-CDK complexes, whereby it inhibits the GI cyclin-associated kinase activity. In addition, previous studies have indicated that Far1 is subject to ubiquitin-mediated proteolysis via the SCF Cdc4 pathway. However, direct biochemical evidence supporting these views has remained elusive. In this study, I reconstitute the ubiquitination pathway for Far1 using recombinant Cln2-Cdc28 and SCFCdc4. I also demonstrate a multiple phosphorylation site dependent binding of Far1 to the Cdc4-Skp1 sub-complex. In addition, evidence is provided that Farl directly inhibits Cln-Cdc28 kinase, and that the affinity of Far1 for Cln-Cdc28 complexes is increased by its Fus3-dependent phosphorylation. Finally, I also provide evidence for a novel pheromone-dependent pathway that inhibits DNA replication downstream of Clb5-Cdc28 kinase activity.
An investigation of the structure and reactivity of coals for injection during blast furnace ironmaking

For more efficient combustion of coal an understanding of the physical and chemical properties of char is required. In this study the effects of pyrolysis conditions on the chemical and physical properties of several North American coals were examined. Chars were prepared in conditions similar to those experienced in the blast furnace during pulverized coal injection. Amorphous fraction and average crystallite height were determined using a quantitative X-ray diffraction technique. Chemical reactivity was measured in terms of intrinsic reactivity. It can be concluded that coals most suitable for pulverized injection in the blast furnace will possess a specific chemical/physical profile as represented by the following parameters: a high and stable amorphous fraction of carbon during pyrolysis and a high reactivity. The effects of a chemical enhancer containing copper sulfate and boric acid were also examined and it is suggested that this addition lowered the ignition temperature and accelerated coal pyrolysis.
In utero origins of carcinogenesis: developmental oxidative stress and vitamin E supplementation

We hypothesize that some cancers may begin before birth in the developing embryo and fetus. A number of normal physiological processes in the developing embryo produce highly reactive forms of oxygen known as reactive oxygen species (ROS), against which the embryo has substantially less protective antioxidative capacity than the adult. ROS can alter cellular signal transduction and/or oxidatively damage critical cellular macromolecules such as DNA, either of which may lead to cancer. The embryo accordingly may be more susceptible to the initiation of cancer that is manifested after birth. Using pregnant outbred CD-1 mice as a developmental model and a short term surrogate for cancer, we first showed that optimal doses of acute intraperitoneal (i.p.) or chronic dietary VE (VE), a common antioxidant, protected the embryo from oxidative DNA damage and embryopathies caused by both constitutive and drug-enhanced levels of ROS. Acute i.p. administration of VE (125 or 250 mg/kg) was substantially more protective against phenytoin-enhanced conceptal DNA oxidation and embryopathies, while the chronic dietary regimen was more protective against constitutive parameters. Dietary administration was limited to the period prior to breeding and until the end of pregnancy, when it was stopped to limit its effects to in utero exposure. Using this optimal dietary VE regimen and tumor-prone p53-knockout mice, we found that conceptal exposure to low-dose VE (0.1% w/w) reduced spontaneous postnatal tumorigenesis in p53 +/- offspring, while high-dose VE (10%) enhanced tumorigenesis in both p53 -/- and +/- offspring. These results indicated that some 11 cancers originate in utero, and postnatal risk can be differentially modulated in a VE dose-dependant fashion by exposure of the developing conceptus to VE.
Identity and hegemony in mid-Tokugawa Japan: a study of the Kyōhō reforms

This dissertation is a historical study of the dynamic interplay between the socio-political reforms and the formation of identity discourse in seventeenth- and early-eighteenth-century Japan. I examine the hitherto neglected ideological dimension of the Kyōhō reforms instituted by the eighth Tokugawa shogun Yoshimune (r. 1716–1745), which have been generally understood as an attempt at regaining the status quo of the samurai rulers. This characterization is correct as far as Yoshimune was resisting the expansion of a money economy, which was fueled by rural surpluses and urbanization. However, it can lead to the view that the mid-Tokugawa period (1650–1750) was just a time of stubborn refusal to change into a capitalistic society. Although such a gross characterization is rejected by many, a question remains: “Why it should have been the samurai, and not the farmers or the merchants, who eventually ‘led’ the process of modernization?”. Using a variety of primary sources, I have tried to answer this question by examining how the bakufu leaders readjusted their socio-political relationships with various social groups in dealing with the rise of a money economy. On the surface, the changes of these relationships took shape as institutional and legal responses to this rise. Yet the most enduring effect of these reforms was the formation of an identity discourse of socio-political relationships between the bakufu leaders and various social groups. I argue that the discourse thus created was able to portray different images of these bakufu leaders. By presenting themselves as a “group” of kinsmen to the daimyo, a “class” of moral leaders to the townspeople, and a “team” of bureaucrats to the farmers, the bakufu leaders transformed Japan into a society that was organic yet incongruent in life experience and collective consciousness. Finally, I suggest that, in order to understand how Japan entered an “early modern” phase since the mid-Tokugawa period, we cannot just treat it as a homogenous “nation” consisting of a dominant samurai class and other subordinate classes. Instead, homogeneity must be understood as consisting of a difficult unity of multiple identities of genealogical groups, economic classes, and political teams.
Technologies of remembrance: literary criticism and Duncan Campbell Scott's "Indian poems"

This thesis conceptualizes literary criticism as a “technology of remembrance.” It works with the theory of “remembrance/pedagogy” which proposes that all remembrance acts are inherently pedagogical. This thesis argues that Canadian literary criticism engages various public remembrance/pedagogies of the history of First Nations-Canadian relations, as those relations have been produced historically through colonial domination. This thesis examines literary criticism, spanning from 1914 to 1996, of Duncan Campbell Scott's canonized “Indian poems.” It also examines Scott's role in the department of Indian Affairs, especially from 1913 to 1932. It reads the literary readings of Scott and asks what is being remembered and forgotten about the colonial history of Canada in the remembrances of Scott? The thesis identifies and critiques three evaluative discourses in Scott literary criticism in terms of what they erase. It suggests two alternative evaluative discourses which are grounded in a counter-hegemonic view of the history of First Nations-Canadian relations.

Keywords: Canadian poetry, History and criticism
Indians in literature
Indigenous peoples in literature
Indians of North America, Canada
Whites, Attitudes
Whites, Canada