Developing Single-Laser Sources for Multimodal Coherent Anti-Stokes Raman Scattering Microscopy

Coherent anti-Stokes Raman scattering (CARS) microscopy has developed rapidly and is opening the door to new types of experiments. This work describes the development of new laser sources for CARS microscopy and their use for different applications. It is specifically focused on multimodal nonlinear optical microscopy—the simultaneous combination of different imaging techniques. This allows us to address a diverse range of applications, such as the study of biomaterials, fluid inclusions, atherosclerosis, hepatitis C infection in cells, and ice formation in cells. For these applications new laser sources are developed that allow for practical multimodal imaging. For example, it is shown that using a single Ti:sapphire oscillator with a photonic crystal fiber, it is possible to develop a versatile multimodal imaging system using optimally chirped laser pulses. This system can perform simultaneous two photon excited fluorescence, second harmonic generation, and CARS microscopy. The versatility of the system is further demonstrated by showing that it is possible to probe different Raman modes using CARS microscopy simply by changing a time delay between the excitation beams. Using optimally chirped pulses also enables further simplification of the laser system required by using a single fiber laser combined with nonlinear optical fibers to perform effective multimodal imaging. While these sources are useful for practical multimodal imaging, it is believed that for further improvements in CARS microscopy sensitivity, new excitation schemes are necessary. This has led to the design of a new, high power, extended cavity oscillator that should be capable of implementing new excitation schemes for CARS microscopy as well as other techniques. Our interest in multimodal imaging has led us to other areas of research as well. For example, a fiber-coupling scheme for signal collection in the forward direction is demonstrated that allows for fluorescence lifetime imaging without significant temporal distortion. Also highlighted is an imaging artifact that is unique to CARS microscopy that can alter image interpretation, especially when using multimodal imaging. By combining expertise in nonlinear optics, laser development, fiber optics, and microscopy, we have developed systems and techniques that will be of benefit for multimodal CARS microscopy.

Livelihood Strategies of Dock Workers in Durban, c. 1900-1959

This dissertation examines the livelihood strategies of African dock workers in Durban, South Africa, between the Anglo-Boer War and the 1959 strikes. These labourers did not conform to common conceptions of radical dock workers or conservative African migrant workers. While Marxist scholars have been correct to stress the working class consciousness of Durban’s dock workers, this consciousness was also more ambiguous. These workers and their leaders displayed a peculiar mix of concern for workers’ issues and defences of the rights and interests of African traders. Many of Durban’s dock workers were not only wage labourers. In fact, only a minority had wages as their only source of income. The Reserve economy played a role in sustaining the consumption levels of their households and, more importantly, more than half of the former dock workers interviewed for this research engaged in some form of commercial enterprise, often based on the pilferage and sale of cargoes. Some also teamed up with township women who sold pilfered goods while the men were at work. This combination of commercial strategies and wage labour has often been overlooked in the literature. By looking at these livelihood strategies, this dissertation considers how rural and urban economies interacted in households’ strategies and reinterprets the reproduction of labour and the household in order to move beyond dichotomies of proletarian versus rural consciousness. The dock workers’ households were neither proletarian households that were forced to reside in the countryside because of apartheid, nor traditional rural homesteads with a missing migrant member. The households were reproduced in three geographically separate spheres of production and consumption, none of which could reproduce the household on its own. These spheres were dependent on each other, but also separate, as physical distance gave the different household members some autonomy. Such multi-nodal households not only bridged the rural and the urban, but equally straddled the formal/informal divide. For many, their employment on the docks made their commercial enterprises possible, which allowed them to retire early from urban wage labour. Consequently, the interests of wage labourers could not be divorced from those of African small-scale entrepreneurs.

A Study of the Development of the Ability of the Archives Department of the Hudson's Bay Company to Carry Out Document Repairs

The objective of this thesis was to determine whether the establishment and operation of an archives services by the Hudson's Bay Company had an effect on the company's ability to carry out document repairs. Data collection methods included reviews of published material, archival records of the Hudson's Bay Company, and semi-structured interviews. The study found that the Hudson's Bay Company's commitment to operating a modern archives service in accordance with accepted archive administration practices had a substantial effect on its ability to carry out document repairs. The principled approach to repair, as practiced by the Public Record Office, was a major influence. A review of secondary sources placed this development squarely within the context of archival developments in 20th century England. Overall, the thesis findings add to the growing conversation about conservation history in England, in particular, archive conservation history as it occurred outside of the Public Record Office in the 20th century, by discussing how some methods of repair that were devised, adopted and extended by the Public Record Office in the 19th and 20th centuries were adopted and applied in the 20th century by a well-established business corporation.

Long-term hydroclimatic change and interannual variability in water sources, Apex River (Iqaluit), Baffin Island, Nunavut

The eastern Canadian Arctic is home to Canada’s largest Indigenous population, which depends on local freshwater sources for drinking water. However, small watersheds have rarely been analyzed for long-term hydrologic response to changing climate. This study aims to address this issue by examining the Apex River, a small watershed with a long hydroclimatic record, near Iqaluit, Nunavut. Particular emphasis was placed on the long-term changes in climate and river discharge, and the seasonal variability of water sources between two snapshots in time, 1983 and 2013. Long-term hydrological data were obtained from gauge station 10UH002, operated by Environment and Climate Change Canada, and long-term meteorological data were acquired from Environment Canada–operated stations near Iqaluit Airport. Breakpoint analysis suggested that long-term mean annual surface air temperatures have increased since 1994. In contrast, no long-term total precipitation or annual discharge changes were observed. However, river flow initiation and cessation analyses of the Apex River flow season indicates that flow extended into the autumn since the 2000s. The 2013 flow season lasted 44 days longer than the 1983 flow season. Systematic river sampling was undertaken throughout the 2013 thaw season to determine contributing proportions of event (snowmelt or rainfall) and pre-event (baseflow) water to river runoff. Results from the stable isotope hydrograph separation for 2013 were compared to findings for 1983. Snow was the main source of water to the river during the snowmelt period in 1983 and 2013, however baseflow was still an important contributor. Although there was high similarity of water sources early in the season in 1983 and 2013, the two years differed during the autumn. In 2013 there was a high rainfall runoff response that was not present in 1983, suggesting high release of late-season sub-surface water storage and an increased sensitivity to late-season rainfall events in 2013. This research provides insights into the hydrologic response of the Apex River to long-term climatic change, and highlights the need for high-quality precipitation and discharge data for effective long-term hydrological assessment.

ROCK OUTCROPS IN THE CANADIAN SHIELD: AN INVESTIGATION OF CONTAMINANT TRANSPORT FROM SURFACE SOURCES IN FRACTURED ROCK AQUIFERS

Flow, recharge and transport dynamics in fractured rock aquifers with low lying rock outcrops is a largely unexplored area of study in hydrogeology. The purpose of this thesis is to examine these topics in an agricultural area in Eastern Ontario. The study consists of a regional scale groundwater quality study, an infiltration experiment that considers bacteria transport from the ground surface to a well, and a numerical modelling study that tests the parameters that affect surface infiltration of a tracer from a rock outcrop to a deeper horizontal fracture. In the water quality study, approximately 65% of the samples contained total coliform, 16% contained E. coli, and 1% contained nitrate-N at greater than 5 mg/L. Occurrence of E. coli increased when considering seasonality, where wells were drilled on rock outcrops, and for shallow well intervals. Nitrate-N did not occur above the Guidelines for Canadian Drinking Water Quality (Health Canada, 2012) of 10 mg/L. Rapid arrival times were observed in the infiltration study for both the microspheres (30 minutes) and a dye tracer (45 minutes) in a well approximately 6.0 m in horizontal and 2.8 m in vertical distance from the tracer source. Transport velocities were approximately 38.9 m/day for the dye tracer and 115.2 m/day for the colloidal tracer. Results of the model runs indicate that overburden can provide an effective protective layer to transport in fractures, that high groundwater velocities occur in larger fracture apertures and higher gradients dilute tracer concentrations, and that lower groundwater velocities occur with smaller fracture apertures and lower gradients result in elevated tracer concentrations. Lower rainfall rates, larger fracture apertures, early tracer time, larger gradients, and lower water levels maintained unsaturated conditions for longer time periods such that tracer transport was delayed until saturated conditions were attained. The overall heterogeneity of this aquifer environment creates a source water protection conundrum where the water quality is generally good, while transport can occur very quickly in proximity to rock outcrops and in areas with limited overburden.

RELIGIOUS SCULPTURE OF THE CHILOÉ ARCHIPELAGO, FROM THE 17TH TO THE 21ST CENTURY

Despite its central role in religious life of the region, the sculptural tradition of the Southern Chilean Chiloé Archipelago, ranging from the 17th century to the present day, has been vastly understudied. Isidoro Vázquez de Acuña’s 1994 volume Santeria de Chiloe: ensayo y catastro remains the only catalogue of Chilote sculpture. Though the author includes photographs of a vast array of works, he does not attempt to place the sculptures within a chronology, or consider their place within the greater Latin American context. My thesis will place this group of works within a chronological and geographical context that reaches from the 16th century to the present day, connected to the artistic traditions of regions as far afield as Paraguay and Lima. I will first consider the works brought to the Archipelago by religious orders – the Jesuits and Franciscans – as well as influences on artistic style and religious culture throughout the 17th, 18th and 19th centuries. I will focus in particular on three works generally considered to be from the 17th and 18th centuries – the Virgin of Loreto at Achao, the Saint Michael at Castro, and the Jesus Nazareno of Caguach – using visual analysis and sifting through generations of primary and secondary sources to determine from where and when these sculptures came. With this investigation as a foundation, I will consider how they inspired vernacular sculptural expression and trace ‘family trees’ of vernacular works based on these precedents. Vernacular artistic traditions are often viewed as derivative and lacking in skill, but Chilote sculptors in fact engaged with a variety of outside influences and experimented with different sculptural styles. I will conclude by considering which aspects of these styles Chilote artists chose to incorporate into their own work, alter or exclude, artistic decisions that shed light on the Archipelago’s religious and cultural fabric.

Essays on Firm Heterogeneity with Empirical Applications in Economic History and Agricultural Economics

This thesis uses models of firm-heterogeneity to complete empirical analyses in economic history and agricultural economics. In Chapter 2, a theoretical model of firm heterogeneity is used to derive a statistic that summarizes the welfare gains from the introduction of a new technology. The empirical application considers the use of mechanical steam power in the Canadian manufacturing sector during the late nineteenth century. I exploit exogenous variation in geography to estimate several parameters of the model. My results indicate that the use of steam power resulted in a 15.1 percent increase in firm-level productivity and a 3.0-5.2 percent increase in aggregate welfare. Chapter 3 considers various policy alternatives to price ceiling legislation in the market for production quotas in the dairy farming sector in Quebec. I develop a dynamic model of the demand for quotas with farmers that are heterogeneous in their marginal cost of milk production. The econometric analysis uses farm-level data and estimates a parameter of the theoretical model that is required for the counterfactual experiments. The results indicate that the price of quotas could be reduced to the ceiling price through a 4.16 percent expansion of the aggregate supply of quotas, or through moderate trade liberalization of Canadian dairy products. In Chapter 4, I study the relationship between farm-level productivity and participation in the Commercial Export Milk (CEM) program. I use a difference-in-difference research design with inverse propensity weights to test for causality between participation in the CEM program and total factor productivity (TFP). I find a positive correlation between participation in the CEM program and TFP, however I find no statistically significant evidence that the CEM program affected TFP.

#DressCodePM & Re-Framing The Niqab: News Sources, Hashtag Activism, and Media Representation

This thesis originates from my interest in exploring how minorities are using social media to talk back to mainstream media. This study examines whether hashtags that trend on Twitter may impact how news stories related to minorities are covered in Canadian media. The Canadian Prime Minister Stephen Harper stated the niqab was “rooted in a culture that is anti-women” on 10 March 2015. The next day #DressCodePM trended in response to the PM’s niqab remarks. Using network gatekeeping theory, this study examines the types of sources quoted in the media stories published on 10 and 11 March 2015. The study’s goal is to explore whether using tweet quotes leads to the representation of a more diverse range of news sources. The study compares the types of sources quoted in stories that covered Harper’s comments without mentioning #DressCodePM versus stories that mention #DressCodePM. This study also uses Tuen A. van Dijk’s methodology of asking “who is speaking, how often and how prominently?” in order to examine whose voices have been privileged and whose voices have been marginalized in covering the niqab in Canadian media from the 1970s and until the days following the PM’s remarks. Network gatekeeping theory is applied in this study to assess whether the gated gained more power after #DressCodePM trended. The case study’s findings indicates that Caucasian male politicians were predominantly used as news sources in covering stories related to the niqab for the past 38 years in the Globe and Mail. The sourcing pattern of favouring politicians continued in Canadian print and online media on 10 March 2015 following Harper’s niqab comments. However, ordinary Canadian women, including Muslim women, were used more often than politicians as news sources in the stories about #DressCodePM that were published on 11 March 2015. The gated media users were able to gain power and attract Canadian Media’s attention by widely spreading #DressCodePM. This study draws attention to the lack of diversity of sources used in Canadian political news stories, yet this study also shows it is possible for the gated media users to amplify their voices through hashtag activism.

DIGITAL HISTORY: DESIGNING VIRTUAL ENVIRONMENTS THAT SUPPORT CRITICAL THINKING AND IDEA EXCHANGE, MOTIVATE AND ENGAGE USERS

In my thesis I argue for the use of system designs that: a) open access to a variety of users and allow for collaboration and idea exchange, while at the same time, b) are designed to motivate and engage users. To exemplify my proposed systems design, I created an interactive and open digital history project focused on Romanian culture and identity during Communism, from 1947, when the Communist Party took power by forcing the King to abdicate, until the revolution in 1989, which marked the end of Communism in Romania (Gilberg, 1990, Boia, 2014). In my project, I present the possibility to recreate Habermas’ notion of public sphere and “the unforced force of the better argument” (Habermas, 1989) and Dewey’s (2004) understanding of democracy as a mode of associated living imbued of the spirit of inquiry within contemporary digital history projects. Second, I outline system designs that motivate and engage users, by satisfying the basic psychological needs outlined in Ryan and Deci’s (2000) self-determination theory: autonomy, competence, and relatedness. Two more concepts are included to complete the proposed digital history project design: presence (Ryan, Rigby, & Przybylski, 2006) and learner hero (Rigby & Przybylski, 2009).

The relationship of E. coli and total coliform culture to the quantitative molecular detection of various fecal indicators, sources, and pathogens in private drinking water wells

Water remains a predominant vector for human enteric pathogens not just for developing countries but also developed nations, where numerous infectious disease outbreaks, linked to the contamination of drinking water have been documented. Private drinking water wells are a source of drinking water that is largely unstudied even though a significant percentage of the population in Ontario relies on wells as their primary water source. As there exists little to no systematic surveillance for enteric infections or outbreaks related to well water sources, these individuals may be at higher risk of waterborne infectious diseases. The relationships between various fecal indicators in the water of private drinking water wells, including E. coli, Total Coliforms (TC) and Bacteroides, and enteric pathogens, including Campylobacter jejuni, Salmonella spp., and Shiga toxin producing E. coli, were studied. Convenience private well water samples collected from various regions of interest during the summer of 2014 underwent membrane filtration and culture to determine quantities of E. coli and TC colony forming units. 289 E. coli positive and 230 TC-only waters were successfully analyzed by individual qPCR assays for the aforementioned enteric pathogens. Microbial source tracking methods targeted to specific Bacteroides were used to determine the source of fecal contamination as either human or bovine. The source of fecal contamination varied by geographic region and is thought to be due to such things as differences in septic tank density and underlying geology, among others. Fecal indicators, E. coli and Bacteroides, were significantly correlated. E. coli as measured by qPCR was more strongly correlated to both total and human-specific Bacteroides genetic markers than culturable E. coli. Lastly, 1.9% of samples showed molecular evidence of contamination with enteric pathogens. Although low, this finding is significant given the limited volume of water available for testing, and suggests a potential health risk to consumers. Knowing the extent of contamination, as well as the biologic source, can better inform risk assessment and the development of potential intervention strategies for private well water in specific regions of Ontario.

The Gentleman-Scholar at Home: Domesticity, Masculinity, and Civility in Dutch Seventeenth-Century Genre Painting

This dissertation examines the gentleman-scholar depicted at home in Dutch seventeenth-century genre paintings, focusing primarily on art created in the Northern Netherlands from the 1630s through the 1670s. The methodological approach is art historical but also pertains to history of architecture, history of dress, and gender studies. Employing the framework of the 'Ages of Man', this thesis investigates three related pictorial themes: the student, the scholar in his prime, and the aged scholar. Variations of male scholarly figures and the accoutrements of the study have a long history in Europe. Prototypical sources include religious history paintings of learned hermit-saints; artistic interest in the allegorical Saturnine persona; portraits of famous scholars; and the iconography of scholarly melancholy implied through vanitas allusions in portraiture and genre paintings. While the majority of Dutch genre paintings pertain to themes of women, male domestic routines form a small but important subset of this imagery and have not been studied. By the 1640s, this subject is readily identified by his setting, clothing, and actions. The ubiquity of scholarly attributes, such as books and globes, paired with the wearing of scholarly robes suggest the merits of intellectual curiosity and the privileges of studying as a pastime and designating a room as a study (studeerkamer). Distinct themes in genre also imply the challenges and rewards of scholarly activity pursued in concert with masculine civic and familial duty. Central to the development of this pictorial theme were: the innovative treatment of learned men by Rembrandt and his circle; the fijnschilder subjects of Dou; and the practice of amateur study by elite men, as suggested by the art of Vermeer. As this dissertation reveals, this convention did not grow to be consistent across the Northern Netherlands, nor was artistic interest limited to university towns. Rather, the larger relevance of scholars in Dutch society is evident in visual and literary sources. The domesticity of this figure in genre painting suggests that scholars mediated between an active and a contemplative life. Societal respect was garnered for scholars through their balance of familial and social duties with the honorable pastime of scholarly leisure.

‘Black Settlers’: Hybridity, Neoliberalism and Ecosystemic Change Among Tonga Farmers of Southern Zambia, 1964-2008

This dissertation examines a process of indigenous accumulation among Tonga farmers in Zambia’s Southern Province. In the 1970s multiple authors concluded that capitalist farmers had emerged among Tonga agro-pastoralists, predominantly within private titled holdings. Relying on archival research, newspapers, secondary sources and extensive oral testimony this thesis fills a 35-year gap on the topic, providing insights into the social and environmental impacts of neoliberal policy among African peasants and capitalist farmers. In contrast to dominant narratives of the post-independence period, this study argues that Zambia did experience a developmental process post-independence, which saw significant achievements made in the agricultural sector, including the doubling of national cattle stocks. The data reveals a painful process of disarticulation beginning in the late 1980s. Following neoliberal adjustment, we observe significant heterogeneity in production systems, some regional specialization, and processes of migration. Most importantly, the thesis uncovers processes of overwhelming ecosystemic change that contributed to livestock epidemics of severe scale and scope. Amazingly, this went largely undocumented because of the simultaneous crisis of the state, which left the national statistics office and other state bodies incapable of functioning from the late 1980s into the 2000s. In response, the Zambian state has introduced a number of neodevelopmental initiatives in the sector, yet the lack of animal traction remained up to 2008 and agricultural production declined, while more capitalized farmers (largely white, and/or with foreign direct investment) have become more significant players in the country. This thesis provides compelling evidence to challenge dominant economic thinking of the Washington institutions as well as many of the common Marxian formulations.