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Instrument Trade Studies for Satellite Remote Sensing of Ammonia
Get PDFAtmospheric ammonia (NH3) has effects on air quality and water quality, but due to its short lifetime and high spatial variablility, obtaining global measurements is a challenge. Advances in radiative transfer modelling and radiometric instrument sensitivity have allowed for satellite NH3 observations to be performed by instruments such as NASA’s Tropospheric Emission Spectrometer and NASA’s Cross-track Infrared Sounder, but these instruments, and others like them, were not designed specifically to measure ammonia. This thesis pursues the development of an optimized instrument to measure ammonia with daily Canadian coverage, good ground spatial resolution (around 1 km), and a high signal-to-noise ratio. The work presented here shows an investigation into the optimized satellite remote sensing system by combining forward modelling, sensor design, and data retrieval algorithms. An imaging Fourier Transform Spectrometer (IFTS) is chosen for the instrument for its wide spectral range and high throughput. A software model of the instrument is used to generate interferograms for each pixel, average four neighbouring interferograms, and recover a spectrum. A secondary model convolves the theoretical instrument lineshape for an off-axis square pixel with the high-resolution radiance. The Rodgers-based retrieval algorithm takes in the spectrum from the full instrument model, and iterates (using the convolution model) to retrieve a surface temperature value and an ammonia profile. These three pieces working together allow for an exploration of different instrument configurations. The investigation of the instrument parameters resulted in two configurations that were selected for further study. These two configurations differed in the number of samples taken of the interferogram and the time required to obtain an interferogram, having undersampling factors of 2 and 3, respectively. In a large-scale run of microwindowed retrievals using high-resolution model fields of NH3, both sets of specifications were able to perform ammonia retrievals. Due to the use of microwindowing, the retrieved surface temperature values had errors large enough to impact the ammonia retrievals. Small tests using a full spectrum retrieval resulted in better performance for both the surface temperature and ammonia retrievals. Both sets of instrument specification meet the requirements for the project, though the case with an undersampling factor of 2 has a lower brightness noise level than the other case
Probing Matter with Photons, Electrons and Neutrons: A Study of Water and Flax
No full textScattering is a vital mechanism through which we interact with the world. This thesis utilizes various
scattering methods to probe the formation of ice structures and interactions between flax based peptides
and gold nanoparticles. The topics covered in this work differ greatly, however the approaches taken to
investigate the respective systems employ the same concepts of scattering. Scattering provides a basis for
the investigation of both water and the flax based semiconducting material. Structural investigations of ice
employing primarily elastic scattering methods supplemented by inelastic scattering methods. Electronic
structure investigations of the flax based semiconductor employed in elastic scattering methods, with the
absorption of visible light also interpreted through the lens of inelastic scattering.
Crystalline phases are typically plotted in phase diagrams with pressure and temperature dependence,
to denote the stability regions of the different structures. Meta-stable regions relating to transformation
and nucleation require further investigation and are often overlooked in these diagrams. Transformation
between adjacent phases portrayed in two dimensions depends on the path taken to achieve the transition.
This is evident in the recent discourse on ice Ih transformations where one can either observe crystal-crystal
transitions, or an intermediate amorphous phase in ice Ih transformation. Dependence on compression rate
and temperature play an important role in the mechanism of ice transformation. Standard clathrate hydrate
stability relations, between pressure and temperature, imply various clathrates are unlikely to form under
high vacuum. However, with appropriate mixtures and heating rates, several improbable hydrates have been
formed. Understanding the mechanism of formation is vital to the study of water mixtures in interstellar
environments.
Solar power is a possible solution to the growing problem of pollution. Conventional solar cells rely
on crystalline inorganic materials to absorb sunlight. Advances in organic semiconducting technology and
nano-fabrication open new avenues for energy production. Here, bio-organic molecules (Linusorbs) derived
from flax seed oil are combined with plasmonic photon absorption in an effort to convert light to electrical
power. Devices fabricated exhibited light absorbing properties however power conversion was limited, with
hysteresis observed while testing under illumination. Further investigation probed the binding interaction of
the peptides and nanoparticles, through insights into the binding angle of the peptide and gold surface.
Employing a combination of elastic and inelastic scattering methods structural transformations in water
and electronic structure of flax based semiconductor were investigated. These studies have very different
applications but are tied together through the methods employed for investigation. Scattering methods can
be used to investigate a wide range of parameters in a variety of systems. This thesis shows a small subset
of possible scattering methods available
Examination of diabetes as a risk factor for osteoporosis among older adults in Korea: A population-based cohort study
Get PDFWith population aging worldwide, the prevalence of diabetes has significantly risen, leading to various complications. Recent evidence suggests there could be potential associations between diabetes as osteoporosis risk. This thesis aimed to examine whether diabetes represents an independent risk factor for osteoporosis onset in Korean adults aged 50 years and older.
The analysis utilized longitudinal data from the Korean National Health Panel Survey from 2008-2018, following 7304 participants aged 50+ years at baseline. Among them, a total of, 1616 individuals with diabetes and 5688 without diabetes were followed for up to 11 years to identify new clinically diagnosed osteoporotic events, including osteoporosis or osteoporotic fractures, based on Korean Standard Disease Classification codes. Kaplan-Meier curves displayed visual comparison of survival over time between diabetes groups and other different risk factors for osteoporosis events, and Cox proportional hazards models calculated adjusted hazard ratios (HRs) of different risk factors.
Over the study period, 794 new osteoporotic events were documented. Diabetes status did not significantly impact osteoporosis risk in multivariate analysis. Older age (70+ years) (vs. 50-60 years) (HR=10.32, 95% CI: 3.25–32.80) and female sex (vs. male) (HR=9.05, 95% CI: 5.32–15.40) emerged as key factors independently associated with greater osteoporosis hazards. Unexpectedly, people with hypertension (vs no hypertension) and previous smokers (vs non-smokers) had lower osteoporosis risk. There was a significant interaction of sex and age, with 60–70-year-old females having higher risk than their male counterparts.
In summary, while diabetes itself was not implicated as an independent predictor, this thesis identified critical demographic and clinical factors for osteoporosis onset in Korean adults aged 50+ years. These findings can guide screening initiatives and future research on underlying mechanisms
Cholera Epidemic, Government’s Interventions and Public Responses in the 1970s, Ìbàdàn, Nigeria
Get PDFThis thesis uses an interdisciplinary approach to studying the Cholera epidemic in Ìbàdàn, Nigeria, in the 1970s. Cholera was considered a ‘stranger’ in the 1970s but is now endemic to the urban center of Ìbàdàn. This thesis demonstrates some of the historical reasons for this change from an interdisciplinary and social history perspective. Previous scholarship has focused more on its medical and epidemiological aspects, whereas I examine this epidemic as a social and medical history feature. I consider the cultural, socio-political, and historical explanations for its spread and persistence in this city. This thesis relies on the archived newspaper reports of the Nigerian Tribune, oral interviews, and indigenous songs that illustrate the cultural understanding of Cholera and its prevention. This thesis discusses how and why the people of Ìbàdàn gave Cholera multiple meanings, interpretations, and identities. I examine the Yorùbá language to expose how indigenous songs reinforced local beliefs about environmental conditions and the limits of public health interventions during the epidemic. The thesis critically discusses the indigenous methods adopted by local communities to curb Cholera, which sheds light on some of the tension that existed between Yorùbá understandings and Western biomedical depictions of the epidemic. Significantly, this thesis offers an understanding of how during an epidemic, health was perceived, formed, negotiated, resisted, nurtured, lived, and contested in places – public toilets, sewage, water system, riversides, and markets. In doing so, it reveals how the class structure, social attitudes, and living conditions affected how people responded to government public health orders, and in some cases, exacerbated the spread of Cholera
Lithium Orotate as an Improved Therapeutic Agent in the Treatment of Mania: Preclinical Evidence from a Murine Model
Get PDFLithium carbonate (LiCO) is a mainstay therapeutic for the prevention of mood-episode recurrence in bipolar disorder (BD). Unfortunately, lithium therapy is plagued by high rates of treatment non-compliance due to the unpleasant adverse effects associated with presently prescribed medications. Given that lithium-induced toxicities correlate with serum exposure, a lithium-based therapeutic that displays similar efficacy concurrent with lesser dosing requirements would likely improve treatment regimen adherence. Lithium orotate (LiOr) may meet this criteria, as previous research suggests it to possess unique uptake characteristics that may enable reductions in dosing and subsequent amelioration of toxicity. Thus, we hypothesized that LiOr is more potent than LiCO due to differential transport, allowing mitigation of side effect incidence consequent to lesser dosing requirements. Dose response curves were established for LiOr and LiCO in male and female mice using an amphetamine-induced hyperlocomotion (AIH) model; AIH captures manic elements of BD and is sensitive to a dose-dependent lithium block. LiCO induced a partial attenuation of AIH at doses of 15 mg/kg in males and 20 mg/kg in females. In contrast, LiOr elicited a near complete blockade at concentrations of just 1.5 mg/kg in both sexes, signifying superior potency and efficacy. Prior application of inhibitors of organic anion transporting polypeptides, or inhibition of orotate uptake into the pyrimidine biosynthesis pathway, completely abolished the effects of LiOr on AIH while sparing those of LiCO, thereby confirming the differential transport and compartmentalization of the two compounds. As proposed in our hypothesis, the increased potency of LiOr translated to improved tolerability: after 14 consecutive days of once daily administration, LiCO, but not LiOr, elicited polydipsia in both sexes, elevated serum creatinine expression in males, and increased serum TSH levels in females. In summation, LiOr demonstrates superior efficacy, potency, and tolerability to LiCO in both male and female mice, likely because of select transport-mediated uptake and incorporation into the pyrimidine biosynthesis pathway
The Turn: The Bank of Canada and the Strategic Communications Revolution
No full textBeginning in the 1980s, governments began to embrace practices associated with the New Public Management (NPM) aimed at making government systems more service-oriented, a disposition that typically translated into more external communication. This trend spread to the central banks in developed countries, which began to embrace openness and transparency in the late 1980s and 1990s. A core tenet of NPM is the establishing of clear policy objectives that can anchor public communications. In monetary policy, the clear policy objective became, almost universally, the achievement of a targeted inflation rate. The Bank of Canada was early to embrace this trend. In targeting this objective, the Bank of Canada gradually, over time, established a communication infrastructure that shaped every aspect of the Bank’s outward communication and became seen as integral to attaining its policy goals. Until the unfolding of the COVID-19 crisis, the Bank’s success in achieving its policy target shielded it from critical, political-level scrutiny. In the aftermath, however, the Bank policies and its communications practices have come under tremendous scrutiny politically, in the media, and within academia. To better understand this current debate, I trace how communications, as a monetary policy instrument, evolved at the Bank of Canada along six lines: the formulation of communication policies, changes to the institutional infrastructure, the hiring, training, and deployment of communication personnel, the shifting structure of central bank texts, the use of outside communication consultants, and the application of communications training. I conclude that, from the beginning, the Bank of Canada viewed its strategic communications function as a key monetary policy tool, inseparable from its inflation target objective. From something that did not exist 30 years ago, strategic communication has become an irreplaceable tool and integral part of the Bank’s operations, especially during crises such as the recent Covid-19 pandemic
Understanding Variable Rate Irrigation under Situations of Field Heterogeneity
No full textDue to the water sensitive nature of potatoes, variable rate irrigation (VRI) technology may be an
effective tool to optimize irrigation in this crop. However, the potential economic and agronomic
benefits of this technology are still unclear, especially over varying agricultural landscapes. We
hypothesize that VRI technology will be a valuable tool when used on potato fields that have a
high degree of soil and topographic heterogeneity. This hypothesis is tested using field-level data
from 2019, 2020 and 2021 collected in the Lethbridge region.
We define a site-specific irrigation-yield production function based on the water balance and
physical properties of unique management zones within a field, specifically soil texture and
topographic variability. The function is used in an economic optimization model to determine the
benefits of VRI technology relative to uniform irrigation.
After calibrating the optimization model with field level data, we conclude that heterogeneity
between management zones has a large impact on the net present value (NPV) of an investment
in VRI. Generally, as heterogeneity between management zones increases, the NPV of an
investment in VRI goes from being negative (a poor investment) to being positive (a strong
investment). Our study is one of the first to apply observational field data in an economic
optimization model to estimate the benefits of VRI relative to uniform irrigation
An Analysis of Water, Energy, and Food (WEF) Security in Alaska
No full textWater, energy, and food (WEF) security has increasingly become a key area of research in sustainable development. Prompted by the United Nations’ Sustainable Development Goals, a large body of research highlights the inter-connectedness of WEF systems and the dangers of their siloed treatment. Simultaneously, more attention is being placed on the lived conditions of remote populations in the Arctic, especially for areas like Alaska, where WEF insecurities are prevalent, yet obscured by national reporting. This research adapted the Global WEF Nexus Security Index to calculate the WEF security scores for Alaska and each of its five regions.
Despite the United States ranking 5th globally in WEF security in this index, Alaska and its 5 regions suffer from considerably higher rates of WEF insecurity. Results indicate that Alaska’s WEF index is 62.73, which is approximately 16 points below the US WEF security score, with Alaska’s sub-index scores ranging from 3.87 to 35.73 points lower than the US. Alaska performs comparable to the US in its water and energy pillars but shows the greatest variability in the food sub-index score with food availability being the lowest sub-pillar score. The regional scores show considerable variability between them, especially for food access and availability, though water accessibility is similar across the regions. The high WEF score of the US obfuscates the reality and variability in WEF security in Alaska and its regions.
Given the current WEF-related challenges faced by residents of Alaska, with their livelihoods closely intertwined with accessible and available WEF resources, this research offers a more nuanced representation of the variable insecurities experienced in Alaska and its most remote regions. This approach, and the results generated, can be used to inform future research that ultimately guides strategic interventions that lend to the WEF security of Alaskan residents
Effect of Transit Systems’ Long-Term Disruptions on Travel Behaviour
No full textThe abstract of this item is unavailable due to an embargo