A new any-point biasing scheme for Mach-Zehnder interferometer modulators which considers the complex phase is proposed. The Mach-Zehnder arm loss imbalance (imaginary part of the phase bias) is found by slightly perturbing the real and imaginary parts of the phase in each arm with low frequency pilot tones and monitoring and manipulating the spectral content at the output. This technique can be used to extend the possible extinction ratio, reduce the phase error, and better quantify the system chirp but also has some performance degradations which are also quantified and discussed. Simulation results indicate that the maximum extinction ratio of a typical modulator can be extended to ≳ 40 dB and maintained in the presence of ambient complex phase drift in the arms. Practical challenges for implementing this method with a silicon Mach-Zehnder modulator are discussed, but the analysis is general to other material platforms.

A new any-point biasing scheme for Mach-Zehnder interferometer modulators which considers the complex phase is proposed. The Mach-Zehnder arm loss imbalance (imaginary part of the phase bias) is found by slightly perturbing the real and imaginary parts of the phase in each arm with low frequency pilot tones and monitoring and manipulating the spectral content at the output. This technique can be used to extend the possible extinction ratio, reduce the phase error, and better quantify the system chirp but also has some performance degradations which are also quantified and discussed. Simulation results indicate that the maximum extinction ratio of a typical modulator can be extended to ≳ 40 dB and maintained in the presence of ambient complex phase drift in the arms. Practical challenges for implementing this method with a silicon Mach-Zehnder modulator are discussed, but the analysis is general to other material platforms.

This project explores the Ktunaxa Nation's creation stories in order to understand the significance of these narratives in the formation and maintenance of the Ktunaxa culture. These stories inform and support the Ktunaxa ways of knowing, their worldviews, their history pre- and post-contact, and their connection to the geography of the Ktunaxa territory. Performance theory has been used to identify the ways in which the stories were shared during the filming of this project, and narrative inquiry has been used to draw out the creation story's central themes and how they relate to the ethnophilosophy of the Ktunaxa people --the interdependence of humans with all of creation; lessons from the animals including Skincu¢ the Coyote; the trauma of residential schools and the impact that has had on the culture and stories of the Ktunaxa; the landforms within the territory; and the responsibilities of all human beings according to these teachings. The research reflections identify truths that emerged through the ceremony of storytelling--rules to live by, ways to approach those within and outside the culture, lessons about being part of a community, and how to pattern the people and the culture off of the surrounding wildlife and geography. These lessons and stories relate to and support the culture of the Ktunaxa, past and present, by providing a connection to the Ktunaxa landscape and all that is within it, and anchors the culture with stories of that place that have been told for many thousands of years. Finally, this project discusses how Aboriginal worldviews contribute to and nourish the field of communication studies.

Propofol is a widely in use anesthetic drug. Propofol’s abuse liability has been supported by many case reports and a few animal studies. However, propofol’s reinforcing properties have not yet been investigated in-depth. In this study, multiple aspects of propofol’s abuse-related behaviour were investigated using the drug self-administration model in rats. METHODS: Rats were subjected to propofol self-administration under a fixed ratio 1 (FR1) schedule and different aspects of propofol self-administration behaviour including acquisition, maintenance of the behaviour under a higher ratio schedule, extinction and reinstatement were investigated. RESULTS: Rats acquired propofol self-administration under a FR1 schedule. The acquired behaviour was maintained under a FR2 schedule, showed a modest variation over a range of doses, and was extinguished upon substitution of vehicle for propofol, showing no reinstatement using a range of priming doses of propofol. CONCLUSION: Propofol has abuse potential showing modest reinforcing properties under our experimental conditions.

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This work investigates the extinction limits of laminar diffusion counterflow flames for various gaseous (methane, syngas, biogas) fuels using a high flow rate counterflow burner designed and built for this work. Equal momenta of the fuel and oxidizer streams were not maintained to provide data to check the fidelity of the numerical schemes and their chemical mechanisms at "non-standard" conditions. Strain rate values at extinction were obtained as a function of fuel mole fraction. Preliminary work with the new burner found that the methane extinction limit results were consistent with results from literature. The results provide insight into the extinction limit conditions of the aforementioned fuels. The strain rate was found to increase with increasing fuel mole fraction. Extinction limit results indicated that fuels with the highest concentration of hydrogen have the greatest extinction limit, which is believed to be attributed to the high diffusivity and reactivity of hydrogen.

This work investigates the extinction limits of laminar diffusion counterflow flames for various gaseous (methane, syngas, biogas) fuels using a high flow rate counterflow burner designed and built for this work. Equal momenta of the fuel and oxidizer streams were not maintained to provide data to check the fidelity of the numerical schemes and their chemical mechanisms at "non-standard" conditions. Strain rate values at extinction were obtained as a function of fuel mole fraction. Preliminary work with the new burner found that the methane extinction limit results were consistent with results from literature. The results provide insight into the extinction limit conditions of the aforementioned fuels. The strain rate was found to increase with increasing fuel mole fraction. Extinction limit results indicated that fuels with the highest concentration of hydrogen have the greatest extinction limit, which is believed to be attributed to the high diffusivity and reactivity of hydrogen.

Propofol is a widely in use anesthetic drug. Propofol’s abuse liability has been supported by many case reports and a few animal studies. However, propofol’s reinforcing properties have not yet been investigated in-depth. In this study, multiple aspects of propofol’s abuse-related behaviour were investigated using the drug self-administration model in rats. METHODS: Rats were subjected to propofol self-administration under a fixed ratio 1 (FR1) schedule and different aspects of propofol self-administration behaviour including acquisition, maintenance of the behaviour under a higher ratio schedule, extinction and reinstatement were investigated. RESULTS: Rats acquired propofol self-administration under a FR1 schedule. The acquired behaviour was maintained under a FR2 schedule, showed a modest variation over a range of doses, and was extinguished upon substitution of vehicle for propofol, showing no reinstatement using a range of priming doses of propofol. CONCLUSION: Propofol has abuse potential showing modest reinforcing properties under our experimental conditions.

The ventral tegmental area (VTA) and its dopaminergic (DA) mesocorticolimbic projections are thought to be essential in the brain’s reward neurocircuitry. In humans and animal experimental subjects, mild electrical VTA stimulation increases dopamine levels and can induce euphoria. Paradoxically, aversive stimuli activate VTA neurons and forebrain DA activity, and excessive electrical stimulation of the VTA exaggerates fearfulness. Research suggests that experimental manipulation of either the amygdala or the VTA has similar effects on the acquisition and expression of Pavlovian conditioned fear. Recently it was demonstrated that electrical stimulation of the amygdala produced fear extinction deficits in rats. Fear extinction involves the progressive dissipation of conditioned fear responses by repeated non-reinforced exposure to a conditioned stimulus (CS). Maladaptive states of fear in fear-related anxiety disorders, such as post-traumatic stress disorders (PTSD) or specific phobias are thought to reflect fear extinction learning deficits. The primary purpose of the present study was to examine the effects of intra-VTA stimulation on fear extinction learning. Using fear-potentiated startle as a behavioural index of conditioned fear, it was found that 120 VTA stimulations paired or unpaired with non-reinforced CS presentations impaired the extinction of conditioned fear. This effect was not apparent in rats that received electrical stimulation of the substantia nigra (SN), suggesting that not all midbrain regions respond similarly. Electrical stimulation parameters did not have aversive affects because rats failed to show fear conditioning when electrical VTA stimulation was used as the unconditioned stimulus. Also, VTA stimulation did not alter conditioned fear expression in non-extinguished animals. Based on the results it is suggested that VTA activation disinhibited conditioned fear responding. Therefore, VTA neuronal excitation by aversive stimuli may play a role in fear-related anxiety disorders thought to reflect extinction learning deficits.