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Profitability of Classifying Pork Meat Quality in Canada
No full textThe Canadian pork industry is a key part of the national agricultural economy, contributing significantly to both local business and international trade. This thesis examines the economic challenges within the industry, focusing on the asymmetric information and quality uncertainty, which highlights issues where buyers cannot easily distinguish between high and low-quality products. This study evaluates the profitability effects of alternative configurations of a potential pork quality grading system (whole carcass) and classification system (primal cuts) for Canadian pork processors.
The study builds a model of processor profitability, which focuses on live animals purchased from producers into key primal cuts of pork. This model is grounded in econometric estimation of pork primal quality and is used to simulate the profitability of different grading scenarios. The potential grading system proposed in this study is based on the premise that primal cuts with higher-than-average quality parameters can command premiums, while those with lower-than-average quality parameters may be subject to discounts. To account for the inherent variability in animal-level quality parameters and market prices, Monte Carlo Simulation (MCS) is employed. Although MCS is not a model per se, it plays a crucial role in simulating various profitability outcomes under different market conditions.
The analysis demonstrates that implementing a quality-based premium and discount system could significantly enhance the profitability of Canadian pork processors. The findings suggest that offering premiums for higher quality products could increase average profitability by up to 6.57%, whereas discounts for lower quality products might reduce profitability by approximately 1.50%. These insights provide valuable guidance for pork processors in optimizing their pricing strategies, ultimately contributing to the sustainable growth of the industry
An investigation of the multi-generational impacts of a naphthenic acid extract isolated from oil sands process-affected water on Daphnia magna
No full textNaphthenic acids (NAs) naturally occur in bitumen deposits and surrounding water sources, such as those present in the Athabasca oil sands deposit in northern Alberta, Canada. Bitumen extraction processes produce extensive volumes of oil sands process-affected water (OSPW) as a by-product, with highly concentrated fractions of bitumen-derived inorganics and organics, including NAs. While NAs are considered the most toxic of all the constituents to aquatic biota, there is little understanding of the long-term impacts of NAs within freshwater systems. The growth and reproductive effects of a naphthenic acid extract (NAE) comprised of NAs derived from an OSPW sample were investigated using the cladoceran, Daphnia magna, in chronic 21 day and multi-generational exposure scenarios. Specifically for the latter, four generations (F0 to F3) were reared under continual NAE exposure. Chronic exposure encompassing a range of potential regional background NAE concentrations (0 – 11.46 mg/L) had no biologically relevant effect on survivorship or reproductive output. However, multi-generational exposure to above background NAE concentrations (25 mg/L) reduced survivorship, particularly in the F0 and F2 generations, to only 65% and 55% of the population surviving, respectively. Population recovery was exhibited in the F3 generation. Significant impacts on growth were also evident, whereby mass was decreased by up to 43%, and body length by up to 19% within generations following 25 mg/L NAE. Reproduction was delayed as well, generally by two days at 25 mg/L NAE, resulting in a decrease in the number of broods (~ 1 – 2 less) achieved within 21 days. In addition, all daphnids in 25 mg/L NAE had significantly increased non-viable neonate production throughout all generations (F0 – F3), increasing by up to 27-fold. Overall, the F2 generation was impacted the most by NAE exposure, and few endpoints demonstrated signs of recovery in the F3 generation. Taken together, these results suggest that exposure to NAE can considerably affect D. magna populations by causing individual mortality, and impact growth and reproductive abilities at high concentrations with effects persisting into the fourth (F3) generation of exposure. Thus, demonstrating the importance of a robust understanding of the sub-lethal impacts and related implications to populations and ecosystems. These results provide novel insight into how previously unexposed D. magna individuals, and subsequent generations, respond to potential environmental increases in exposure to NAs resulting from accidental release via OSPW spills or seepage into groundwater. This research may help to better inform potential future policies pertaining to OSPW treatment and contribute to developing safe potential release guidelines following treatment, should this be considered in the future
Three Essays on Behavioral Finance and the Over-the-Counter Market
No full textThis thesis explores the dynamics of the U.S. Over-The-Counter (OTC) market, a decentralized and underexplored segment of the financial system, through three essays that integrate behavioral finance theories and market structure analysis. It investigates the unique characteristics of OTC stocks, focusing on the role of behavioral biases in shaping risk premiums, the comovement of OTC returns with listed stocks, and the influence of social media on trading dynamics.
The first essay provides an updated analysis of OTC market anomalies, revealing that traditional risk premiums, such as size and illiquidity, largely align with those in listed markets, signifying increased integration. However, volatility and momentum premiums in OTC markets remain distinct, driven predominantly by retail investors' intrinsic preference for lottery-like payoffs. This behavioral bias leads to the overvaluation of high-volatility stocks and sustains the momentum premium.
The second essay investigates the integration between the OTC and listed markets, focusing on the comovement of returns and trading activities. The findings highlight that retail investor behavior plays a pivotal role in driving this integration, with speculative trading preferences and behavioral biases creating strong linkages between the two markets. The analysis reveals that OTC stocks, traditionally viewed as independent from listed markets, exhibit significant comovement with speculative segments of listed portfolios, particularly during periods of heightened retail sentiment.
The third essay examines the influence of StockTwits, a prominent social media platform, on OTC trading dynamics. The findings reveal that increased social media activity is associated with short-term excess returns, enhanced liquidity, and elevated volatility in OTC stocks, particularly those exhibiting lottery-like characteristics. Interestingly, the analysis also indicates that heightened social media attention is linked to reduced crash risk in these stocks.
By integrating behavioral finance with market structure analysis, this thesis contributes to a deeper understanding of the OTC market, emphasizing the critical role of investor psychology and the evolving influence of digital platforms on trading behaviors. These findings underscore the need for regulatory considerations and the refinement of traditional asset pricing models to account for the idiosyncratic dynamics of OTC trading
Investigating the physiological role of leupaxin in the function of CD8+ T cells and their contribution to antitumor immunity
Get PDFLeupaxin, a member of the paxillin family of adaptor proteins, plays a role in cell signaling, particularly in the integrin pathway. Although it is highly expressed in activated CD8+T cells, its function in these cells remains unclear. Previous research from our lab demonstrated that leupaxin undergoes phosphorylation following TCR and integrin (LFA-1) stimulation, suggesting its involvement in both signaling pathways within CD8+ T cells. These pathways are essential for various physiological processes in CD8+ T cells, including migration, cytotoxic functionality, and proliferation. I hypothesize that leupaxin as an adaptor protein regulates several key aspects of CD8+ T cells, including adhesion, migration, proliferation, cytotoxic activity, and impacts on anti-tumor response mediated by CD8+ T cells. To investigate the physiological role of leupaxin in CD8+ T cells, our lab previously generated Leupaxin-Knockout (LKO) mice, which are viable and T-cell development is intact. The LKO mice were created by deleting the leupaxin gene in all tissues using a Cre-loxP system, starting from leupaxin-floxed (Lfl/fl) mice. The Lfl/fl mice, in which leupaxin is expressed in all tissues, serve as the control group for the study.
I found that leupaxin deficiency leads to increased spreading of CD8+ T cells on different extracellular matrix (ECM) components while reducing their migration velocity on ICAM-1. Investigation into the role of leupaxin in CD8+ T cell proliferation revealed that leupaxin deficiency does not impair CD8+ T cell proliferation. However, under stimulatory conditions with anti-CD3 + IL-2, LKO CD8+ T cells exhibit enhanced proliferation compared to Lfl/fl cells. My findings indicate that leupaxin deficiency does not hinder the cytotoxicity of CTLs in vitro. This intact function aligns with in vivo results, where tumor growth was significantly reduced in LKO mice. The primary objective of chapters 4 and 5 of this thesis was to investigate the impact of leupaxin deficiency on CD8+ T cell-mediated antitumor responses in murine models of lymphoma and breast cancer. LKO mice showed significant tumor growth suppression in both tumor models compared to Lfl/fl mice. In the lymphoma model, this suppression was associated with an increased infiltration of CD8+ T cells in LKO tumors. Similarly, tumor growth inhibition in Cre CD8-Lfl/fl mice, where leupaxin is deleted explicitly in CD8+ T cells, closely resembled the suppression observed in LKO mice. This finding underscores the critical role of CD8+ T cells in mediating the enhanced antitumor response observed in leupaxin-deficient mice. The suppression of tumor growth in lymphoma models was also age dependent. At 8 weeks of age, no difference in tumor growth was observed between LKO and Lfl/fl mice. However, by 16 weeks of age, a significant inhibition of tumor growth was observed in LKO mice, suggesting an age-related enhancement of antitumor immunity. The robust antitumor responses observed in LKO mice across both tumor models were linked to an elevated frequency of effector and memory (Teff/Tem) CD8+ T cells in tumors. Additionally, a distinct subset of Teff/Tem CD8+ T cells expressing the NK1.1 marker—known for its potent antitumor properties—was significantly enriched in the tumors of LKO mice compared to Lfl/fl controls. This enrichment was consistently observed in both lymphoma and breast cancer models, highlighting the importance of this NK1.1+CD8+ T cell population in driving the enhanced antitumor effects in leupaxin-deficient mice.
In conclusion, this study is the first to comprehensively elucidate the physiological role of leupaxin in CD8+ T cells, particularly in antitumor immunity. The findings indicate that leupaxin deficiency enhances CD8+ T cell-mediated antitumor responses by increasing the frequency of effector and effector memory (Teff/Tem) CD8+ T cells expressing NK1.1 in an age-dependent manner. These insights deepen our understanding of leupaxin's regulatory role in CD8+ T cell responses and present promising avenues for novel cancer immunotherapies
Towards a better QA process
No full textFor web archivists, Quality Assurance (QA) is a lengthy manual process that involves inspecting hundreds or thousands of archived websites to see if they have been captured correctly, i.e., resemble the original. This paper describes how this process can be automated by using image comparison measures to detect quality problems in archived websites. To this end, we created a suite of Python tools to 1) create screenshots of live websites and their archived counterparts, and 2) calculate the image similarity between the screenshots. We tested our code on four web archive collections to test the efficacy and usefulness of six different image similarity measures. We compared their scores to human judgments of the quality of archived websites obtained from Amazon Mechanical Turk (AMT). Our results show that the Structural Similarity Index (SSIM) and the Normalized Root Mean Square (NRMSE) scores are able to distinguish between high and low-quality archived websites. Our research at every step was informed by the specific needs and challenges of web archivists. Having methods such as the one presented here can allow cultural heritage institutions or researchers to more quickly and effectively detect low-quality content and produce high-quality web archives
