Serotonin (5-HT)-containing neuroepithelial cells (NECs) of the gill filament are believed to be the primary O2 chemosensors in fish. In the mammalian carotid body (CB), 5-HT is one of many neurotransmitters believed to play a role in transduction of hypoxic stimuli, with acetylcholine (ACh) being the primary fast-acting excitatory neurotransmitter. Immunohistochemistry and confocal microscopy was used to observe the presence of the vesicular acetylcholine transporter (VAChT), a marker for the presence of ACh, and its associated innervation in the gills of zebrafish. VAChT-positive cells were observed primarily along the afferent side of the filament, with some cells receiving extrabranchial innervation. No VAChT-positive cells were observed in the gills of goldfish; however, certain key morphological differences in the innervation of goldfish gills was observed, as compared to zebrafish. In addition, in zebrafish NECs, whole-cell current is dominated by an O2-sensitive background K+ current; however, this is just one of several currents observed in the mammalian CB. In zebrafish NECs and the CB, membrane depolarization in response to hypoxia, mediated by inhibition of the background K+ (KB) channels, is believed to lead to activation of voltage-gated Ca2+ (CaV) channels and Ca2+-dependent neurosecretion. Using patch-clamp electrophysiology, I discovered several ion channel types not previously observed in the gill chemosensors, including Ca2+-activated K+ (KCa), voltage-dependent K+ (KV), and voltage-activated Ca2+ (CaV) channels. Under whole-cell patch-clamp conditions, the goldfish NECs did not respond to hypoxia (PO2 ~ 11 mmHg). Employing ratiometric calcium imaging and an activity-dependent fluorescent vital dye, I observed that intact goldfish NECs respond to hypoxia (PO2 ~ 11 mmHg) with an increase in intracellular Ca2+ ([Ca2+]i) and increased synaptic vesicle activity. The results of these experiments demonstrate that (1) ACh appears to play a role in the zebrafish, but not goldfish gill, (2) goldfish NECs likely signal hypoxic stimuli primarily via the central nervous system (CNS), (3) goldfish NECs express a broad range of ion channels as compared to the NECs of zebrafish, and (4) goldfish NECs rely on some cytosolic factor(s) when responding to hypoxia (PO2 ~ 11 mmHg). This thesis represents a further step in the study of neurochemical and physiological adaptations to tolerance of extreme hypoxia.

This thesis is a dissertation to support the development of new domino pericyclic oxy-Cope/ene/Claisen/Diels-Alder reaction, diversity oriented synthesis of PPAPs scaffold via sequential one pot cascade reaction and ethyl aluminum sesquichloride catalyzed highly hindered Diels-Alder reaction. The first part concentrates on the domino pericyclic oxy-Cope/ene/Claisen/Diels-Alder reaction. As a result of this study, we have developed a general methodology for rapidly constructing complex diterpenes and discovered a thermal oxy-Cope/ene/Claisen/Claisen rearrangement, applied to the synthesis of trans decalin benzofurans. The second part involved the development of an efficient synthetic approach towards bicyclo[3.3.1]nonenone core found in many natural products, via a sequential Diels-Alder/gold(I)-catalyzed 6-endo-dig cyclization and its application to the synthesis of a diversified library of PPAPs. Finally, we have developed an efficient synthetic methodology for the formation of cyclohexene rings bearing quaternary carbon centers via an ethyl aluminum sesquichloride mediated highly hindered Diels-Alder reaction. This method solved an important problem encountered in the synthesis of many natural products including PPAPs. This methodology opened new opportunities in the total synthesis of PPAPs.

In view of the recent implementation of a publicly funded rotavirus vaccination program in Ontario, we undertook studies to help guide the design of a safety evaluation of the vaccine with respect to intussusception. We used administrative data to develop and validate an algorithm for intussusception, and quantified its incidence in Ontario. We also conducted a systematic review of study designs used to evaluate post-licensure vaccine safety, and discussed each design’s strengths and weaknesses. The validated algorithm for intussusception was sensitive (89.3%) and highly specific (>99.9%). We observed the highest mean incidence (34 / 100,000) in males <1 year of age. While other designs are more robust, the inability to ascertain individual vaccination status from Ontario’s administrative data dictated our selection of an ecological design for safety evaluation of rotavirus vaccine. Data assimilated from this thesis represent a critical step toward the timely evaluation of rotavirus vaccine safety in Ontario.

This dissertation is composed of three studies that examined illness-related stigma, depressive symptoms and attachment style among patients living with HIV and Hepatitis C (HCV). The first study examined the psychometric properties of a brief HIV Stigma Scale (B-HSS) in a sample of adult patients living with HIV (PHA) (n=94). The second study developed and explored the psychometric properties of the HCV Stigma Scale in a sample of adult patients living with HCV (PHC) (n =92). Psychometric properties were evaluated with classical test theory and item response theory methodology. The third study explored whether illness-related stigma mediated the relationship between insecure attachment styles (anxious attachment or avoidant attachment) and depressive symptoms among PHA (n =72) and PHC (n=83). From June to December 2008, patients were recruited to participate in a questionnaire study at the outpatient clinics in The Ottawa Hospital. Findings indicated that the 9-item B-HSS is a reliable and valid measure of HIV stigma with items that are highly discriminatory, which indicates that items are highly effective at discriminating patients with different levels of stigma. The 9-item HCV Stigma Scale was also found to be reliable and valid with highly discriminatory items that effectively differentiate PHC. Construct validity for both scales was supported by relationships with theoretically related constructs: depression and quality of life. Among PHA, when HIV stigma was controlled the relationship between anxious attachment style and depression was not significant. However, the relationship between avoidant attachment style and depressive symptoms decreased but remained significant. Among PHC when HCV stigma was controlled the relationship between insecure attachment styles and depressive symptoms was not significant. Dissertation results emphasize the importance of identifying patients experiencing illness-related stigma and the relevance of addressing stigma and attachment style when treating depressive symptoms among PHA and PHC.

In the first part of this thesis, we present the first non-trivial small value estimate that applies to an algebraic group of dimension 2 and which involves large sets of points. The algebraic group that we consider is the product ℂ× ℂ*, of the additive group ℂ by the multiplicative group ℂ*. Our main result assumes the existence of a sequence (PD)D ≥1 of non-zero polynomials in ℤ [X1, X2] taking small absolute values at many translates of a fixed point (ξ, η) in ℂ × ℂ* by consecutive multiples of a rational point (r, s) ∈ (ℚ*)2 with s = ±1. Under precise conditions on the size of the coefficients of the polynomials PD, the number of translates of (ξ, η) and the absolute values of the polynomials PD at these points, we conclude that both ξ and η are algebraic over ℚ. We also show that the conditions that we impose are close from being best possible upon comparing them with what can be achieved through an application of Dirichlet’s box principle. In the second part of the thesis, we consider points of the form θ = (1,θ1 , . . . ,θd-1 ,ξ) where {1,θ1 , . . . ,θd-1 } is a basis of a real number field K of degree d ≥ 2 over ℚ and where ξ is a real number not in K. Our main results provide sharp upper bounds for the uniform exponent of approximation to θ by rational points, denoted λ ̂(θ), and for its dual uniform exponent of approximation, denoted τ ̂(θ). For d = 2, these estimates are best possible thanks to recent work of Roy. We do not know if they are best possible for other values of d. However, in Chapter 2, we provide additional information about rational approximations to such a point θ assuming that its exponent λ ̂(θ) achieves our upper bound. In the course of the proofs, we introduce new constructions which are interesting by themselves and should be useful for future research.

Single Carrier Frequency Division Multiple Access (SC-FDMA) is a multiple access transmission scheme that has been adopted in the 4th generation 3GPP Long Term Evolution (LTE) of cellular systems. In fact, its relatively low peak-to-average power ratio (PAPR) makes it ideal for the uplink transmission where the transmit power efficiency is of paramount importance. Multiple access among users is made possible by assigning different users to different sets of non-overlapping subcarriers. With the current LTE specifications, if an SC-FDMA system is operating at its full capacity and a new user requests channel access, the system redistributes the subcarriers in such a way that it can accommodate all of the users. Having less subcarriers for transmission, every user has to increase its modulation order (for example from QPSK to 16QAM) in order to keep the same transmission rate. However, increasing the modulation order is not always possible in practice and may introduce considerable complexity to the system. The technique presented in this thesis report describes a new way of adding more users to an SC-FDMA system by assigning the same sets of subcarriers to different users. The main advantage of this technique is that it allows the system to accommodate more users than conventional SC-FDMA and this corresponds to increasing the spectral efficiency without requiring a higher modulation order or using more bandwidth. During this work, special attentions wee paid to the cases where two and three source signals are being transmitted on the same set of subcarriers, which leads respectively to doubling and tripling the spectral efficiency. Simulation results show that by using the proposed technique, it is possible to add more users to any SC-FDMA system without increasing the bandwidth or the modulation order while keeping the same performance in terms of bit error rate (BER) as the conventional SC-FDMA. This is realized by slightly increasing the energy per bit to noise power spectral density ratio (Eb/N0) at the transmitters.

The Pearson statistic, a well-known goodness-of fit test in the analysis of contingency tables, gives little guidance as to why a null hypothesis is rejected. One approach to determine the source(s) of deviation from the null is the decomposition of a chi-squared statistic. This allows writing the statistic as the sum of independent chi-squared statistics. First, three major types of contingency tables and the usual chi-squared tests are reviewed. Three types of decompositions are presented and applied: one based on the partition of the contingency table into independent subtables; one derived from smooth models and one from the eigendecomposition of the central matrix defining the statistics. A comparison of some of the omnibus statistics decomposed above to a χ2(1)-distributed statistic shows that the omnibus statistics lack power compared to this statistic for testing hypothesis of equal success probabilities against monotonic trend in the success probabilities in a column-binomial contingency table.

Females exhibit lower sudomotor response than males, which has been attributed to physiological differences between sexes. It is well accepted that non-thermal factors (i.e. baroreceptors and osmoreceptors) can influence thermoeffector responses. Even though there are sex-related differences in baroreceptor modulation of thermoeffector responses, it remains unknown if differences in osmoreceptor modulation could explain the lower sudomotor response in females. Therefore, we examined if there are sex-related differences in osmoreceptor modulation of sweating and cutaneous vascular conductance (CVC). A group of nine males and nine females were passively heated while in an isosmotic and hyperosmotic state. The onset and thermosensitivity of sweating and CVC were calculated and compared between groups and conditions. We show that the delay in onset of sweating and CVC is similar between sexes. However, thermosensitivity of sweating was lower in females than males. We conclude that hyperosmolality does not modulate the decreased sudomotor activity in females.

The purpose of this study was to understand the significance of emotions and the body in the lived creative experience in dance. Using a phenomenological approach, I was interested in gaining a deepened understanding of the creative experiences of members of Canada’s contemporary dance community. Currently, dance is taught in multiple contexts of education including K-12 arts education and physical education, recreational studios, university settings such as in faculties of education, kinesiology, and fine arts, and in conservatory-style pre-professional training programs. As a result, there appears to be little evidence of a holistic pedagogical approach. Coming from a predominantly ballet-oriented dance training background, I wanted to learn what it’s like to create dance; specifically how contemporary dancers use their bodies and emotions as part of their creative process. I had the pleasure of being an invited guest, writer, speaker, and researcher at the 2008 Canada Dance Festival (CDF), a biennial dance festival that takes place in Ottawa, Ontario, Canada. Results shed light on rarely discussed facets of the creative experience in dance. This study explores the way dancers optimally want to feel, how they prepare to feel the way they want to feel, what obstacles they encounter, and what strategies allow them to revisit their optimal feel within their creative experience in dance. Doing so, the role of the body and the emotions in dance are better understood. A description of the 2008 Canada Dance Festival as a transactional space also surfaced. There, the CDF is understood as a place where the art of dance’s perceived meaning and values are discussed, and ultimately negotiated. Finally, results also contributed to an enriched understanding of artistic identity in dance as an ongoing process of becoming. With an enhanced pedagogical understanding of dance education, a final discussion unearths implications of this work and shines a spotlight on future research in dance scholarship.

The concept of social media is top of mind for Canadians today. Decision makers, such as the Canadian government, try to identify ways in which they can benefit from tools such as Twitter. This thesis is an investigative analysis that studies how the Canadian government currently uses social media networks. Based on the conceptual framework of Rogers’ diffusion of innovations (2003) and Qualman’s socialnomics theory (2013), the study aims to define how members of the Parliamentary Press Gallery use the Government of Canada tweets. Through a series of interviews with members of the press and government communications executives, a themed analysis was conducted to demonstrate how Twitter is being used and if a dialogue exists between federal institutions and reporters. The research unveiled that the Government of Canada uses social media as a one-to-many broadcasting channel, not actively engaging in online dialogue with members of the press. Conversely, journalists use Twitter as a wire service to obtain instant information, and to gain insight from the consumers. However, they are not interested in conversing with the public service on social media as they want to protect the exclusivity of their story, and they criticize the anonymity of the government corporate accounts as having an impact on its credibility.