VictorJuiz/thesis huggingface dataset:
Organic Residue Analysis and the Earliest Uses of Pottery in the Ancient Middle East

In this dissertation, I discuss the role of organic residue analysis in identifying economic activities and subsistence practices associated with the first uses of pottery in the Middle East, and present the results of my analyses of 280 potsherds recovered from 22 Neolithic and early Chalcolithic settlements dating between 7300 and 4300 cal BC. The adoption of pottery vessels in the early agricultural villages and pastoral encampments of the Middle East was not a uniform phenomenon, with this new technology not immediately of benefit, apparently, to all human groups. Results of my analyses have demonstrated that ‘conventional’ solvent extraction and alkaline hydrolysis techniques have limited utility in the recovery of diagnostic organic compounds from pottery from early ceramic horizons in the Middle East (Gregg et al. 2007), and that increased yields can be achieved through the use of a microwave-assisted liquid chromatography protocol (Gregg et al. 2009; Gregg and Slater in press). My research has established that there is greater diversity in the fractionation of stable carbon isotopes associated with the synthesis of fatty acids in domesticated animals than has previously been reported. In many instances, the ranges of modern isotopic values that have been used to categorize animal fats in archaeological potsherds in northern Europe cannot distinguish between the ∂13C ratios of ancient dairy residues and carcass fats of ruminant and non-ruminant species in central Europe or the Middle East (Gregg et al. 2009; Gregg and Slater in press). In light of these results, I evaluate the diagnostic potential and limitations of different methodological approaches in the recovery and characterization of organic residues, and propose a series of measures that will allow more confident categorization of the substances in early pottery vessels from the Middle East. I also make a number of recommendations for archaeologists considering the use of organic residue analysis, and suggest some practical ideas on how to develop the degree of confidence necessary to assess the methods used in acquisition of molecular and isotopic data, and ultimately, to evaluate the adequacy of the analytical criteria used to address specific archaeological research questions.

Keywords: Organic residues
Near Eastern prehistory
First uses of pottery
Stable isotope geochemistry
Advisor: Miller, Heather
A Design-rule-Based Constructive Approach To Building Traceable Software

The maintenance of large-scale software systems without trace information between development artifacts is a challenging task. This thesis focuses on the problem of supporting software maintenance through a mechanism for establishing traceability relations between the system requirements and its code elements. The core of the proposed solution is a set of design rules that regulates the positional (e.g., package), structural (e.g., class), and behavioral (e.g., method) aspects of the system elements, thus establishing traceability between requirements and code. We identify several types of requirements each of which can be supported by design rules. We introduce a rule-based approach to software construction and demonstrate that such a process can support maintainability through two mechanisms: (a) traceability and (b) reduction of defect rate. We distinguish our work from traditional traceability approaches in that we regard traceability as an intrinsic structural property of software systems. This view of traceability is in contrast to traditional traceability approaches where traceability is achieved extrinsically through creating maps such as the traceability matrices or allocation tables. The approach presented in this thesis has been evaluated through conducting several empirical studies as well as building a proof-of-concept system. The results we obtained demonstrate the effectiveness and usefulness of our approach.

Keywords: Traceability
Software Maintenance
Design Rules
Advisor: Wortman, David
Race, Ethnicity, Immigration And Jobs: Labour Market Access Among Ghanaian And Somali Youth In The Greater Toronto Area

This thesis uses focus group interviews and survey questionnaires to examine perceptions of Ghanaian and Somali youth, residing in Toronto, about barriers to their labour market access. The emphasis is on perceptions that deal with labour market discrimination based on race, ethnicity and recency of immigration. The results show that perceptions of discrimination based on these factors are widespread among all of the participants interviewed or surveyed. This suggests a very strong belief that employment discrimination is pervasive and persistent in the Toronto labour market. The findings also show that the perceptions of discrimination are largely driven by ‘lived discriminatory’ experiences faced by the participants as well as revealing their desire for fairness and equality in society. The perceptions of discrimination negatively affected the level of trust the research participants have in people and institutions as well as impacting their sense of belonging to their communities and the wider society. The relationship between perceptions of discrimination and low levels of trust and sense of belonging is established in the findings of the Ethnic Diversity Survey. The consequences of this impact on the research participants and their communities are high levels of unemployment, high poverty rates and participant dissatisfaction with their own communities and society at large. It is my belief that this thesis contributes to the debate about the significance of discrimination due to race, ethnicity and immigrant status in the Canadian labour market.

Keywords: Race
Ethnicity
Immigration
Labour Market
Youth
Black
Social Capital
Transnationalism
Advisor: Livingstone, David W.
Synthesis, Characterization and Thermal Decomposition of Hybrid and Reverse Fluorosilicones

Traditional fluorosilicones contain a siloxane backbone and pendant fluorinated group leading to low temperature ductility and excellent thermal stability. However, acidic or basic catalysts can reduce the thermal stability from a potential 350 °C to 150 °C. The predominant decomposition mechanism is through chain scission and it is hypothesized that preventing this will result in polymers with higher thermal stability. Three approaches were taken to prevent chain scission. First, a series of hybrid fluorosilicones based on (trifluorovinyl)benzene were synthesized through condensation polymerization with initial decomposition temperatures of approximately 240 °C. These were compared to similar aromatic polyethers and removal of the ether oxygen lowered the initial decomposition temperature by approximately 190 °C demonstrating the importance of this oxygen to the stability of polyethers. Second, reverse fluorosilicone (fluorinated backbone and pendant siloxane) terpolymers of chlorotrifluoroethylene (CTFE), vinyl acetate (VAc) and methacryloxypropyl-terminated polydimethylsiloxane (PDMSMA) were synthesized in supercritical CO2 (scCO2) or by emulsion polymerization. Chain scission was prevented as initial decomposition occurred between 231 and 278 °C. In both the emulsion and scCO2 cases, VAc was essential in facilitating cross-propagation between CTFE and PDMSMA and the branching was similar suggesting polymerization media does not affect polymer structure. Emulsion-based polymers had higher molar masses and thermal stability whereas comparable scCO2 polymers had higher yields and incorporated more PDMSMA. Third, a series of homo-, co-, and terpolymers of CTFE, VAc and methacryloxypropyl-terminated silsesquioxane (POSSMA) were synthesized representing the first synthesis of POSSMA containing polymers in scCO2 and demonstrating reverse fluorosilicones can be synthesized without VAc. Chain scission was prevented as initial decomposition occurred from 244 to 296 °C with thermal stability increasing with CTFE content to a limit. Decomposition of the polymers was examined and mechanism elucidated. In air, the copolymers give 40 to 47 wt% char since the silsesquioxane oxidizes to SiO2 while in N2, no residue is seen. In contrast, the terpolymers give a carbonaceous residue of approximately 20 wt% in N2. The flammability and surface properties of the polymers were examined with the terpolymers having flammability similar to p(CTFE) and surface properties comparable to p(POSSMA) giving a low-flammability, hydrophobic polymer.

Keywords: fluorosilicone
decomposition
polymer
synthesis
fluoropolymer
supercritical carbon dioxide
chlorotrifluoroethylene
vinyl acetate
polyhedral oligomeric silsesquioxane
flammability
thermal
thermo-oxidative
Advisor: Shoichet, Molly
Oxidation Resistant Catalyst Support for Proton Exchange Membrane Fuel Cells

In automotive applications, when proton exchange membrane fuel cells (PEMFCs) are subjected to frequent startup-shutdown cycles, a significant drop in performance is observed. One reason for this drop in performance is oxidation of the carbon in the catalyst layer when cathode potential excursions as high as 1.5V are observed. In this work, non-carbon based catalyst support materials were studied. The materials investigated include: tungsten carbide (WC), tungsten oxide (WOx), and niobium (Nb) or tungsten (W) doped titania. Platinum was dispersed on commercial samples of WC and WOx. Stability tests were performed by stepping the materials between 0.6 to 1.8V. Higher stability of both WC and WOx was observed compared to carbon based commercial catalyst (HiSpec 4000). The performance of Pt supported on WC or WOx was found to be lower than that of Pt/C due to poor dispersion of Pt on these low surface area commercial powders. High surface area Nb and W doped titania materials synthesized using sol-gel techniques were subjected to several heat treatments and atmospheres, and their resulting physical properties characterized. The materials’ phase changes and their impact on electrical conductivity were evaluated. W doped titania was found to be resistive, and for Nb doped titania, the rutile phase was found to be more conductive than the anatase iii phase. Conventionally, 10-50 wt% Pt is supported on carbon, but as the non-carbon catalyst support materials have different densities, similar mass ratios of catalyst to support will not result in directly comparable performances. It is recommended that the ratio of Pt surface area to the support surface area should be similar when comparing Pt supported on carbon to Pt supported on a non-carbon support. A normalization approach was investigated in this work, and the ORR performance of 40wt.%Pt/C was found to be similar to that of 10wt.%Pt/Nb-TiO2. Fuel cell performance tests showed significantly higher stability of Pt on Nb doped titania catalyst when compared to conventional Pt on carbon catalyst. It was found that, of the materials studied, only the rutile phase of Nb doped titania synthesized under reducing conditions is useful as a potential PEMFC catalyst support.

Advisor: Kesler, Olivera
Low-income Mothers, Provisioning, and Childcare Policy: A Vision of Shared Caring

This research examines how childcare policy in Ontario, Canada assists and constrains low-income urban women’s strategies of provisioning for their children. Childcare policy refers to the range of programs that assist families in reconciling paid work and parenthood. In Ontario, Canada, these programs include childcare fee subsidies, tax deductions, parental leave policies, child benefits/allowances and a program regulating live-in caregivers. Provisioning is used to capture an array of daily work-related activities (e.g. paid, unpaid and caring labour) that mothers perform to ensure their children’s survival and well-being. The qualitative study, based on individual semi-structured interviews with 20 low-income mothers living in an urban community, found that women carry out various activities in provisioning for their children. Some of these are familiar and visible activities such as providing domestic caring labour, engaging in the labour market, and undertaking volunteer work in the community. Others are less visible tasks such as sustaining their health and that of their children, making claims/asserting their rights, and ensuring safety. Low-income urban mothers provision under numerous constraints. A continuous shortage of money and childcare issues are at the core of these constraints. The study also found that the mothers encounter a variety of barriers in the community, such as a limited availability of social and community services and a high level of violence/criminal activity in their neighbourhoods. Issues related to poor health, an inadequate diet, or the necessity of caring for children with special needs further constrain women’s lives. Limited English language skills, racial barriers, and the struggles of adapting to a new country add to the multi-dimensional barriers facing low-income urban mothers. The research indicates that mothers use a variety of strategies to counter these barriers; however, these strategies cost women in terms of their time as well as their physical, mental and emotional energy. Childcare policy assists to a certain extent by providing some support to low-income mothers. Enhancements to the existing policies have potential benefits; however, they are like patches on a leaky bucket. Ultimately, the bucket needs to be replaced with a new way of envisioning family responsibilities, work and childcare.

Keywords: childcare policy
family policy
low income
mothers
poverty
immigrants
government policy making
provisioning
Advisor: Neysmith, Sheila
Almost CR Quantization via the Index of Transversally Elliptic Dirac Operators

Let M be a smooth compact manifold equipped with a co-oriented subbundle E ⊂ TM. We suppose that a compact Lie group G acts on M preserving E, such that the G-orbits are transverse to E. If the fibres of E are equipped with a complex structure then it is possible to construct a G-invariant Dirac operator [special characters omitted] in terms of the resulting almost CR structure. We show that there is a canonical equivariant differential form with generalized coefficients [special characters omitted](E, X) defined on M that depends only on the G-action and the co-oriented subbundle E. Moreover, the group action is such that [special characters omitted] is a G-transversally elliptic operator in the sense of Atiyah [Ati74]. Its index is thus defined as a generalized function on G. Beginning with the equivariant index formula of Paradan and Vergne [PV08b], we obtain an index formula for [special characters omitted] computed as an integral over M that is free of choices and growth conditions. This formula necessarily involves equivariant differential forms with generalized coefficients and we show that the only such form required is the canonical form [special characters omitted](E, X). In certain cases the index of [special characters omitted] can be interpreted in terms of a CR analogue of the space of holomorphic sections, allowing us to view our index formula as a character formula for the G-equivariant quantization of the almost CR manifold (M, E). In particular, we obtain the “almost CR” quantization of a contact manifold, in a manner directly analogous to the almost complex quantization of a symplectic manifold.

Keywords: Quantization
Contact geometry
Transversally elliptic operators
Equivariant index theory
Advisor: Meinrenken, Eckhard
Numerical Experiments in Core-collapse Supernova Hydrodynamics

The explosion of massive stars involves the formation of a shock wave. In stars that develop iron cores, this shock wave stalls on its way out due to neutrino emission and the breakup of heavy nuclei flowing through the shock. For the explosion to succeed, a fraction of the gravitational binding energy of the collapsed core that is radiated in neutrinos needs to be absorbed by the material below the shock. How much energy is needed depends on the interplay between non-spherical hydrodynamic instabilities, neutrino heating, and nuclear dissociation. This thesis seeks to understand this interplay through numerical experiments that model the key physical components of the system and separate them out to examine their individual effects. Specifically, one- and two-dimensional time-dependent hydrodynamic simulations are performed to study the effects of non-spherical shock oscillations, neutrino-driven convection, and alpha particle recombination on the dynamics of the system and the critical heating rate for explosion. We find that nuclear dissociation has a significant effect on the linear stability and saturation amplitude of shock oscillations. At the critical neutrino heating rate for an explosion, convection due to a negative entropy gradient plays a major role in driving dipolar shock motions. One dimensional explosions are due to a global instability involving the advection of entropy perturbations from the shock to the region where the accretion flow cools due to neutrino emission. Large scale shock expansions in two-dimensions are due to a finite amplitude instability involving the balance between buoyancy forces and the ram pressure of the flow upstream of the shock. During these expansions, a significant amount of energy is released when nucleons recombine into alpha particles, constituting a significant last step in the transition to explosion. The critical neutrino heating rate for an explosion depends sensitively on the starting radius of the shock relative to the radius at which the binding energy of an alpha particle is comparable to the gravitational binding energy.

Keywords: supernovae
hydrodynamics
Advisor: Thompson, Christopher
Social Conservatives and the Boundary of Politics in Canada and the United States

This dissertation investigates social conservative activism in the American Republican Party and in four parties of the Canadian right: the Progressive Conservative Party, Reform Party, Canadian Alliance Party, and Conservative Party of Canada. While issues like gay and lesbian rights and abortion became politically contentious in both countries during the late 1960s, American social conservatives emerged earlier than their Canadian counterparts and enjoyed considerably more success. Understanding this contrast explains an important part of the difference between Canadian and American politics and explicates a key aspect of modern conservatism in North America. The argument developed here focuses on different norms about the boundary of politics held in right-wing parties in the two countries. Norms are embedded components of institutions that codify the “logic of appropriateness” for actors within a given institution (March and Olsen 1989, 160) and both construct and regulate the identities of political actors (Katzentstein 1996). The recognition of norms has been an important development in organizational theory, but one that has never been applied to modern office-seeking parties (Ware 1996, Berman 1998). Qualitative case studies establish that many Republicans understood both sexuality and appeals to religion as politically legitimate throughout the period under investigation. In Canada, alternatively, Progressive Conservatives saw such questions as being inappropriate grounds for political activity. This norm restricted social conservative mobilization in the party. It was only when the Reform Party upset both the institutions and ideology of Canadian conservatism that social conservatives began to gain prominence in Canadian politics. Since then, the success of Canadian social conservatives has been limited by Canada’s political culture and institutions but they are now, as their American counterparts have long been, consistently recognized by other Canadian conservatives as partners in the conservative coalition.

Keywords: Conservatism
Party Politics
Social Issues
Canadian Politics
American Politics
Advisor: Forbes, Hugh Donald
Fermions and Bosons on an Atom Chip

Ultra-cold dilute gases of neutral atoms are attractive candidates for creating controlled mesoscopic quantum systems. In particular, quantum degenerate gases of bosonic and fermionic atoms can be used to model the correlated many-body behaviour of Bose and Fermi condensed matter systems, and to study matter wave interference and coherence. This thesis describes the experimental realization and manipulation of Bose-Einstein condensates (BECs) of 87Rb and degenerate Fermi gases (DFGs) of 40K using static and dynamic magnetic atom chip traps. Atom chips are versatile modern tools used to manipulate atomic gases. The chips consist of micrometre-scale conductors supported by a planar insulating substrate, and can be used to create confining potentials for neutral atoms tens or hundreds of micrometres from the chip surface. We demonstrate for the first time that a DFG can be produced via sympathetic cooling with a BEC using a simple single-vacuum-chamber apparatus. The large 40K-87Rb collision rate afforded by the strongly confining atom chip potential permits rapid cooling of 40K to quantum degeneracy via sympathetic cooling with 87Rb. By studying 40K-87Rb cross-thermalization as a function of temperature, we observe the Ramsauer-Townsend reduction in the 40K-87Rb elastic scattering cross-section. We achieve DFG temperatures as low as T = 0.1TF , and observe Fermi pressure in the time-of-flight expansion of the gas. This thesis also describes the radio-frequency (RF) manipulation of trapped atoms to create dressed state double-well potentials for BEC and DFG.We demonstrate for the first time that RF-dressed potentials are species-selective, permitting the formation of simultaneous 87Rb double-well and 40K single-well potentials using a 40K-87Rb mixture. We also develop tools to measure fluctuations of the relative atom number and relative phase of a dynamically split 87Rb BEC. In particular, we observe atom number fluctuations at the shot-noise level using time-of-flight absorption imaging. These measurement tools lay the foundation for future investigations of number squeezing and matter wave coherence in BEC and DFG systems.

Keywords: ultra-cold atoms
Bose-Einstein condensates
degenerate Fermi gases
quantum degenerate gases of neutral atoms
sympathetic cooling
radio-frequency double-well potentials
matter wave interference
atom chips
laser cooling
magnetic trapping
quantum atom optics
quantum statistics
Advisor: Thywissen, Joseph H.