VictorJuiz/thesis huggingface dataset:
The evolution of combined versus separate sexes in Wurmbea (Colchicaceae)

The evolution of separate sexes has occurred repeatedly throughout the history of the flowering plants in a wide variety of life-history contexts and ecological conditions. Yet despite its frequent origin, gender dimorphism in plants is relatively rare, occurring in less than 10% of angiosperm species. Theoretical models predict at least two factors are important in selection for gender dimorphism--resource allocation and the avoidance of inbreeding. Both of these factors can limit the seed fitness of cosexual plants relative to females, aiding their invasion and maintenance in populations of cosexuals, hence the establishment of dimorphic sexual systems. Stressful environmental conditions may favour (1) resource reallocation by limiting investment into expensive functions, such as fruits and seeds, or (2) the expression of inbreeding depression through effects on the mating system. Using ' Wurmbea' (Colchicaceae) as a study system, I investigated recent proposals that aridity has favoured the evolution of gender dimorphism through altered patterns of resource allocation or changes in pollination and mating. Phylogenetic analysis revealed multiple evolutionary transitions between monomorphic and dimorphic sexual systems of 'Wurmbea'. I found no evidence for a causal role of aridity in selection for separate sexes, although some species probably invaded dry habitats after gender dimorphism was established. One transition involved 'W. dioica' ssp. ' alba', a polymorphic subspecies in Western Australia containing populations, that are either monomorphic or dimorphic for gender. I found substantial morphological and ecological differentiation between the sexual systems of 'W. dioica '. Gender dimorphism was associated with drier microsites, allocation patterns favouring resource acquisition and storage, and physiological traits related to higher photosynthetic capacity and lower water use efficiency. In contrast, gender monomorphism was associated with wetter microsites, greater investment into leaves and flowers with increased resource availability and greater water use efficiency. Smaller flower size was favoured by low precipitation in both sexual systems. I found evidence that flower size and style morphology have important consequences for pollen dispersal in 'W. dioica', and may have mediated a change in the mating system in resource-limited sites. Thus, gender dimorphism in 'W. dioica' may have resulted from selection to enforce outcrossing in resource-limited conditions.
"You must remember this..." The law of recovered memory in Canada

"Recovered memory" refers to memories which are rendered unavailable to consciousness for a period of time, and later recovered or returned. In the legal context it is used to refer to memories of historical child sexual abuse. This thesis concerns the interface between psychology and law on the issue of recovered memory. It demonstrates how existing psychological concepts and theories of memory inform and determine how science approaches, analyses, and ultimately pronounces on the validity of new concepts and theories in the same field, such as those surrounding recovered memory. Similarly, it examines the law's note historical orientation to memory, particularly as it contributes to the law's approach to recovered memory revealed in the evidential issues identified in the case law by this thesis. In addition, the thesis illuminates the correspondence, or lack thereof, between psychological theories of memory and both legal conceptions and expectations of memory.
Identification and characterization of an Escherichia coli ribosomal ATPase

Protein synthesis is a unifying process of all living cells. The macromolecules involved in translation, ribosomes, RNAs and protein factors, as well as the mechanisms of protein synthesis, are all largely conserved across the spectrum of cell types. In this thesis, a ribosome-associated ATPase, RbbA, is identified in 'Escherichia coli' extracts. RbbA can bind both 70S ribosomes and 30S ribosomal subunits. The ATPase activity of RbbA increases two-fold in the presence of purified 70S ribosomes. RbbA cross-reacts with antibody raised against the fungal-specific translation factor EF-3, and like EF-3, RbbA stimulates the synthesis of polyphenylalanine from a poly(U) template 'in vitro'. Cross-linking data show that RbbA lies near 30S ribosomal subunit protein S1 and binds to a poly(G)-rich region of the 30S subunit rRNA, 16S rRNA. This region of the ribosome is known as the decoding region of the ribosome and is important for the binding of aminoacyl-tRNAs to the ribosomal A-site. Upon binding of RbbA, 16S rRNA undergoes a specific conformational change that has been demonstrated previously to affect translational fidelity. EF-Tu, which escorts aminoacyl-tRNAs to the A-site of the ribosome, is also capable of binding with RbbA. Hygromycin, an antibiotic that interferes with protein synthesis by binding to the decoding center of the ribosome, is able specifically to inhibit the ribosomal ATPase activity by displacing RbbA from the ribosome. Together, the data suggest that RbbA, the first ATPase demonstrated to be involved in prokaryotic protein synthesis, plays a major role in protein chain elongation.
Adhesion and Durability of Latex Paint on Wood Fiber Reinforced Polyethylene

The low surface free energy of polyethylene is a barrier for painting wood fiber reinforced polyethylene, particularly with water borne paints. In this study, the surface characteristics of compression molded WFRP, containing 50% w/w wood fiber, were investigated by means of optical and scanning electron microscopy. Image analysis was employed to measure the amount of exposed wood fiber as a function of mold temperature. The WFRP surface was modified using mechanical treatments and corona discharge. To evaluate the efficiency of the pretreatment methods, contact angle measurements were used to characterize the surface energy of the specimens. In addition, a scratch test and a 45° peel test were employed to measure the paint/substrate adhesion on both treated and untreated WFRP surfaces. The results indicated that, for the conditions used in this study, corona treatment improved the wettability of the WFRP surface and increased the paint/substrate adhesion better than mechanical treatments. The exposed wood fiber enhanced the paint/substrate adhesion and long term performance of the painted WFRP
Exploring the social construction of chronic obstructive pulmonary disease

A social constructionist perspective was used to investigate the experience and meaning of illness for the individual living with Chronic Obstructive Pulmonary Disease (COPD). Twenty-three persons with COPD were interviewed, and data were analyzed using a modified Grounded theory method. The major findings suggest that COPD has acute and chronic aspects to its illness course. There exist two pre-trajectories. Common to both COPD pretrajectories is the absence of the notion of chronic illness. These pretrajectory phases correspond to the early stage of the disease course. However, individuals with COPD do not acknowledge a chronic illness process. This shapes their response to illness, expectations and coping abilities. It also makes this group, among chronic illnesses, uniquely suited to sick role adoption. The findings of this study served to extend the literature on the illness experience of COPD, and chronic illness. In the thesis recommendations are made for practice and future research.
Competition policy for small market economies, market conditions under the magnifying glass

For the most part, competition policy literature focuses on large economies. Yet the economic paradigms on which such competition policies are based do not necessarily apply to the many small market economies that exist around the world. As this thesis demonstrates, the size of an economy affects the optimal competition policy that should be adopted by it. It demonstrates the effects of market size both on rules of thumb used in competition policy as well as on more general policy prescriptions, such as policy goals, trade-offs and remedial tools. The implications of this thesis extend beyond domestic competition policy to the evaluation of the current global trend towards the world-wide harmonization of competition policies.
Transition, understanding the dynamics of the in-patient rehabilitation process for older persons with a cancer diagnosis

A qualitative study was conducted using grounded theory methodology to examine the process that older persons with a cancer diagnosis experienced in an in-patient rehabilitation program. Six individuals with a cancer diagnosis were interviewed twice, within a week of being transferred from acute care to in-patient rehabilitation and just prior to their discharge. Participants had a variety of functional deficits that resulted from cancer or its treatment. Content analysis of the tape-recorded interviews revealed that participants experienced a transition while in the rehabilitation program. The transition consisted of three phases which were (a) taking stock of the situation, (b) looking and moving forward, and (c) preparing for home. The three phases consisted of five major categories. The categories were (a) getting and staying motivated, (b) actively participating, (c) regaining function, (d) adopting adaptive behaviours, and (e) remaining hopeful. The three phases and the five categories derived from the data formed the substantive theory that described the transitional processes that occurred for older persons with cancer in an in-patient rehabilitation program. Implications for practice and suggestions for further research were examined.
Non-orthogonal forward link for future CDMA cellular systems

In this thesis we propose the use of non-orthogonal forward link for future CDMA cellular systems. The non-orthogonal forward link uses long PN codes as the spreading codes. The use of long PN codes has a few advantages over the common practice of using orthogonal codes. It allows the design of a flexible air interface that can easily accommodate multimedia traffic, and has the potential to offer substantial capacity improvement by exploiting future advances in source and channel coding. In addition, it allows hand-off-without-signaling which may have application in highly-dynamic propagation environments. We study the novel issue of correlation of interference at different diversity branches in a non-orthogonal forward link. Its effect on the performance of diversity combining is analysed. Simulation on system capacity, with the correlation effect taken in consideration, reveals that with the use of proper antenna diversity and channel coding techniques, nonorthogonal forward link offers roughly equal capacity comparing to orthogonal forward link, and has the potential to offer substantially higher capacity with future advances in source and channel coding. Performance of hand-off-without-signaling is also analysed.
Towards a fibre optic nucleic acid biosensor, thiazole orange derivatives as sensitive fluorescent probes to detect DNA hybridization

Single-stranded DNA oligonucleotides (dT20) were immobilized onto the functionalized surface of fused silica optical fibres ' via' a hexaethylene glycol linker. 1-hydroxyethyl-4-[(3-methyl-6-methoxybenzothiazole-2-ylidine)methine] quinolium bromide (TOMEHE) was synthesized and characterized by mass spectrometry and uv-visible absorption spectrophotometry. Absorption of TOMEHE in the presence of single-stranded DNA or double-stranded DNA was found to be linear (r 2 = 0.998 and 0.995, respectively) over the concentration range studied (1:60, 1:30, 1:12, 1:3 and 1:1 dye:base or base pair ratios). Hybridization events were detected using a fibre optic nucleic: acid detection scheme whereby delivery of radiation to the surface of the optical fibre was achieved by total internal reflection. Fluorescence from TOMEHE associated with the DNA membrane was coupled into the fibre and measured. The fluorescence intensity maximum of TOMEHE associated with immobilized dT20 on the surface of the optical fibre was observed to lie at 560 ± 3 nm. The wavelength of the fluorescence maximum for TOMEHE when associated with hybidized DNA on the fibre surface was not observed to be significantly different from that of single-stranded DNA. TOMEHE demonstrated a 10-fold greater fluorescence enhancement over EB when bound to double-stranded DNA, but also displayed a 2.5 fold enhancement over EB when associated with single-stranded DNA. The linearity of fluorescence for TOMEHE when bound to double-stranded DNA was poor (r2 = 0.566) for the range studied (1:60, 1:30, 1:12, 1:3 and 1:1 dye:base pair ratios), suggesting that this dye may not be suitable for incorporation into the nucleic acid detection strategy described herein.
Spatial organization in international economics

This thesis consists of three essays that study key aspects of the spatial organization of economic activity. The first essay develops a theoretical framework that helps explain (i) the considerable productivity dispersion among plants, (ii) why exporters are more productive than non-exporters (iii) why exporters tend to be larger than non-exporters, (iv) why the fraction of plants that export is small, (v) why even among those plants that do export, the fraction of revenues earned from exporting tends to be small and (vi) why older plants tend to grow output at a slower rate than younger firms. It is also revealed that country size, as measured by the number of markets in a country, can have a significant effect on how quickly firms grow. The essay develops a novel way to solve dynamic optimization problems when "state-space" constraints are present. The solution strategy is applicable to a wide variety of problems in which agents are not constrained now but expect to be constrained in the future. The second essay develops a general equilibrium model in which oligopolistic competition leads to agglomeration. When trade costs fall sufficiently far, one region will become highly industrialized (the core) while the other region will become deindustrialized (the periphery). Higher demand for services and manufacturing workers will increase wages in the core but depress wages in the periphery. As a result, global inequality is seen to be an inevitable consequence of globalization and international trade. The third essay develops a model in which an increase in the volatility of firm-specific productivity shocks increases national income. Labour market pooling ensures that workers are always moving from less productive firms to more productive firms, thus raising the average productivity of the workforce. It is for this reason that firms tend to locate close to other firms, especially when they employ the same type of labour. It is shown that countries whose firms experience temporarily large firm-specific productivity shocks will run current account surpluses. The labour market pooling model is examined with data on job turnover. It is shown that the top 5 percent of most concentrated industries tend to have rates of labour turnover which are nearly twice the national average.
Ultrafast all-optical switching based on InGaAsP grown by He-plasma-assisted molecular beam epitaxy

We present the first experimental study of the optical properties of HELP InGaAsP (InGaAsP grown by He-plasma-assisted molecular beam epitaxy) relevant to all-optical switching, and the first demonstration of picosecond switching using this material. We observed an optical response time of 15 ps, a nonlinear index change as large as 0.077, a sharp absorption band edge, and a small absorption tail in HELP InGaAsP. The unique coexistence of ultrafast response, large interband nonlinearity, and small band-tail absorption, never before reported, makes HELP InGaAsP particularly suitable for ultrafast all-optical switching. Additionally, faster response (subpicosecond) was achieved by doping the material with beryllium, and moderate doping (up to ~1018 cm-3) did not significantly alter the absorption edge. We systematically studied the response time variations with doping concentration, annealing temperature, carrier density, and wavelength. We conclude that, (a) Be doping reduces the response time by compensating for donor-like mid-gap states, thus increasing the electron trap concentration; (b) annealing removes defects responsible for fast carrier trapping; (c) the response time increases with carrier density due to limited trap states; (d) the response time varies with wavelength due to difference in electron and hole trapping cross-sections, which were determined based on experimental results and a phenomenological two-trap-level rate equation model. We investigated two types of HELP-InGaAsP-based all-optical switching devices, the nonlinear directional coupler (NLDC) and the asymmetric Fabry-Pérot (AFP) switch. Based on numerical modelling and waveguide loss measurements, we conclude that, while HELP-InGaAsP-based passive NLDCs are in principle viable, practical devices will tend to require high switching energy, and will likely experience low contrast and high insertion loss. We demonstrated that AFP devices will outperform NLDCs in contrast ratio, throughput, bandwidth, switching time, and polarization-sensitivity. We designed and fabricated three prototype AFP devices, and achieved polarization-independent switching with a 5 ps switching window, 20 dB contrast ratio, >=10% throughput, 25-40 nm bandwidth (at >=10 dB contrast ratio), and 0.5-1.4 pJ/[mu]m2 switching energy density. HELP InGaAsP is a promising material for ultrafast switching and other applications requiring ultrafast nonlinear operations. The HELP-InGaAsP-based AFP device we demonstrated is well suited for demultiplexing high-bit-rate data in practical optical communications systems.
Bone-bonding to alkali/heat treated titanium

This study tests the hypothesis that surface topographical changes induced by alkali/heat treatment of cpTi metal implants will cause bone to mechanically bond with the surface of the implants. Therefore, the changes of the surface features of machined and acid-etched cpTi metal were characterized both prior to and after alkali/heat treatment. Such surface features were also analyzed with respect to the biological responses of both osteoconduction and bone-bonding. It was found that alkali/heat treatment of both machined and acid-etched surfaces (1) renders the surface oxide microporous, (2) significantly increases Ra, Rq, SA, SAI values, and (3) significantly increases surface wettability. The level of the osteoconductivity was found to be significantly higher on untreated or treated acid-etched vs. untreated-machined samples. Conducting the detachment tests it was found that considerable forces were required to detach the bone from alkali/heat treated surfaces and the cement line of the newly formed bone was interdigitating with the microporosity of the alkali/heat treated surfaces.
Risk factors for active tuberculosis among foreign-born persons arriving in Ontario

Migration has resulted in the resurgence of tuberculosis (TB) as a public health concern in developed countries. In Ontario over 80% of cases of TB occur among foreign-born persons. The study determined risk factors for TB among this group. This was a population based case-control study. Cases were enrolled from the Ontario Reportable Disease Information Service. Data was obtained from this source and databases maintained by Citizenship and Immigration Canada. Risk factors for the development of active TB included age at time of immigration, referral for post-landing surveillance (PLS) at time of immigration, world region of origin, time since landing and educational attainment. Persons referred for PLS, despite being at increased risk, accounted for only 13% of all the cases of TB. The provincial TB control program must develop alternative strategies to control TB among foreign-born persons in Ontario. This study provides key information for the development of such strategies.
Genetics of pancreatic adenocarcinoma

Recent evidence suggests that susceptibility to pancreatic adenocarcinoma may be inherited. This thesis examines germline and somatic mutations in pancreatic cancer patients. In the first series of experiments, 102 such patients were studied to define (i) the proportion belonging to hereditary cancer syndrome families, and (ii) the frequency of germline mutations of various cancer predisposing genes in patients with a personal or family history of cancer. Ina second related set of experiments, the role of germline 'p16' mutations in patients with both pancreatic adenocarcinoma and malignant melanoma was investigated. In the last set of experiments, the relationship between a specific type of tumor K-'ras' mutation and a history of smoking was examined. This work shows that known causes of genetic predisposition are an important risk factor only in a small proportion of pancreatic cancer patients and that there are probably, as yet unidentified genes predisposing to this disease.
Properties and regulation of small-conductance anion channels in a rat microglia cell line

Microglia, resident brain immune cells, are involved in brain pathologies; e.g., stroke. Using appropriate bath and pipette solutions, we isolated a whole-cell anion current in a rat microglia cell line and created a biophysical and pharmacological fingerprint. We also investigated the regulation of the underlying channels. The whole-cell current was outwardly rectified and displayed time- and voltage-independent gating. The channels were volume sensitive, modulated by intracellular ion content, had a selectivity sequence similar to Eisenman I $(\rm I\sp- > Br\sp- \approx Cl\sp-)$ and were permeable to the excitatory amino acid glutamate. The following traditional and non-traditional anion channel blockers inhibited the current: NPPB, flufenamic acid, glibenclamide, suramin and riluzole. Channel activation depended on cellular ATP and was not supported by GTP$\gamma$S alone. The channel properties are consistent with a potential role in glutamate neurotoxicity during pathological conditions. The biophysical and pharmacological properties of the anion channels are distinct from other known chloride channels; e.g. CIC-2 and CIC-3.
Start-up of a laboratory-scale anaerobic sequencing batch reactor treating glucose

A laboratory-scale anaerobic sequencing batch reactor (ANSBR) treating glucose at 21°C was started-up and loaded to an organic loading rate (OLR) of 3 kg·m-3·d-1. Higher loadings were not achieved due to acid accumulation and pH inhibition. Operational parameters such as influent concentration, total cycle time, and fill-to-cycle time (F/C) ratios were identified that could be modified to improve the reactor's performance without the need for external pH control. In addition, a straightforward experimental method was described that could determine substrate-specific kinetic parameters and active biomass fractions necessary for use in mathematical models of the ANSBR process. Low levels of aceticlastic methanogens (0.48%) and total active biomass (17.4%) were measured in the microcosm studies likely due to solids washout and temperature "shock". Model predictions of the five sets of ANSBR operational conditions studied in the laboratory generally agreed with experimental results for 6000 mg/L glucose influent, but differed for 3000 mg/L.