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New Estimates of Snow Water Availability in the Northern Regions of North America.
No full textSeasonal snow has a crucial role on freshwater supply in mountainous regions and high latitudes. The advent of remote sensing data and Earth System reanalysis products has opened enormous opportunities for estimating snow water availability at larger scales. Despite these technological advancements, still estimating the water stored in snow and determining its variability in space and time pose major challenges. One major issue is limitations in the benchmarking studies and the fact that while several new datasets are introduced, little is known about their accuracy, reliability and robustness. The second issue is related to the way that water stored in the snowpack is assessed using the concept of Snow Water Equivalent (SWE). Most importantly, maximum annual SWE does not reflect the losses of snow water during winter melts– a phenomenon that has become widespread due to the rising temperature and more frequent winter rain as a result of climate change. In addition, SWE does not take into account snow cover extent, and therefore cannot distinguish whether changes in stored water in the snow correspond to changes in snow depth or snow cover. To address the first challenge, a formal benchmarking is performed to test three key snow fields of a newly released reanalysis product, ERA5-Land, over the area of Canada and Alaska, ~9% of global land in which snow processes have a critical role on water supply. The considered snow variables are snow depth, snow cover and SWE, from which snow density can be also retrieved. The ERA5-Land’s snow depth and SWE fields are intercompared with Canadian Meteorological Centre’s (CMC’s) snow depth and SWE, whereas snow cover field is tested against MODIS satellite observations as the reference. Special care is made to assess how spatial and temporal patterns of change and persistence are reconstructed using ERA5-Land’s snow field over 21 ecological regions that cover the domain. In addition, the spatial patterns discrepancies between ERA5-Land’s snow fields and corresponding reference products are explored to inspect whether they entail there is any significant dependence with latitude, longitude and elevation, which points to a systematic bias in ERA5-Land data. Based on this benchmarking attempt, it is advised against the use of ERA5-Land’s snow depth and SWE estimates in Canada and Alaska, while estimates of snow cover and snow density can be still used although with cautions, particularly for local assessments, which may require bias-correction. To address the second challenge, a new and more physically-appealing metric, Snow Water Availability (SWA), is defined that take into account snow cover extent in conjunction with snow depth and snow density. Based on the findings of the benchmarking attempt, four monthly estimates of SWA are established over Canada and Alaska by integrating CMC snow depth fields with ERA5-Lands’s and CMC’s snow density as well as MODIS’s and ERA5-Land’s snow cover during the water years of 2000 to 2020 at 25×25 km2 spatial resolution. Using these SWA estimates, the implications on water availability over 25 drainage regions in Canada and Alaska are explored and discussed. It is concluded that while Canada and Alaska as a whole has gained substantial amount of SWA during the study period, the strategically important drainage regions in western Canada have lost substantial amount of SWA since the beginning of the century. This can jeopardize regional water resource management in some of the world’s most important food baskets in Canadian Prairies, revealing the urgency for regional adaptation to maintain the water, food and energy security in Canada
Navigating Peer Conflict: Children’s Anticipated Disclosures to their Mothers about Experiences of Harming and Being Harmed by a Friend
Get PDFThis thesis examined children’s anticipated disclosure to parents regarding hypothetical situations of being harmed and harming a friend, along with their descriptions and evaluations of expected maternal responses. A sample of 196 children (92 boys, 104 girls) across three age groups (Mages = 8.57, 12.47, 17.58 years, respectively) responded to questions following two hypothetical conflict scenarios in which they were described as harming or being harmed by a friend (order counterbalanced). The first research aim was to examine whether children were more likely to disclose being harmed than harming a friend. Findings revealed that children were significantly more likely to disclose when they had been harmed. The second aim examined children’s expectations of maternal responses. Children expected more supportive responses and fewer negative judgments from their mothers when they had been harmed. The third aim explored whether children found maternal responses equally helpful across both events. Contrary to our expectations, children perceived their mothers’ responses as more helpful when they had harmed a friend. Lastly, the fourth aim examined how perceptions of maternal helpfulness were associated with children’s likelihood to disclose future experiences of harm. Children who perceived their mothers’ responses as more helpful were more likely to anticipate disclosing future experiences of harm. Children’s age and gender moderated some of these findings, and overall relationship quality also contributed uniquely to predicting disclosure patterns. Our study suggests disclosure of peer conflict and parent-child communication are fostered by a supportive, nonjudgmental environment in the context of high-quality, trusting relationships
Critiquing Rational Psychology: Meier and Kant on the Immortality of the Soul
Get PDFIn this paper, I aim to enrich scholarship on Georg Fredrich Meier and extend scholarship on Immanuel Kant’s critique of speculative metaphysics. Meier is a relatively underexamined philosopher who worked within the eighteenth-century Wolffian tradition of Rationalism and influenced Kant’s critical philosophy. Meier was critical of the metaphysical claims of the Rationalist school, particularly in his essay Thoughts on the State of the Soul after Death. Meier aimed his critique at Rational Psychology, which boasted proofs for the existence of the immortal soul and claims of certainty regarding its substantiality, simplicity, and maintenance of personality after death. Famously, in the Paralogisms section of the Critique of Pure Reason, Kant also critiques speculative metaphysics and claims about the qualities of the soul. In the Paralogisms, Kant directs his critique toward Rational Psychology but does not refer directly to the fallacious arguments of the Wolffian tradition of Rational Psychology. Kant’s avoidance of mentioning the Wolffian tradition has led to some degree of scholarly neglect for this essential context. I will argue that both Kant and Meier are critics of Rational Psychology who levy the same kind of argument against the claims of Rational Psychology: both argue that proof of the claims about the soul are beyond the capacities of human reason to obtain. In targeting the ground of these claims, the capacities of human reason itself, both Kant and Meier make room for faith, despite differing on the degree to which that faith is necessary for morality
Generative AI Image Tools for Creative Work: Social and Ethical Perspectives in Japan from Computer Science Graduate Students and Experts
Get PDFThe growing interest to incorporate generative artificial intelligence (GenAI) image tools into creative workflows has raised concerns about the social and ethical implications it may have on Japan’s creative industries. This exploratory study is the first to discuss what oversights may emerge on such issues from prospective Japanese generative AI researchers- computer science (CS) graduate students studying in Japan. From June 2023 to August 2023, nine CS graduate students studying in Tokyo were interviewed to understand how CS graduate students in Japan discuss GenAI image tools’ 1) technical aspects, 2) social and ethical aspects, and 3) cultures in AI research, as well as three experts to investigate the 4) legal, social, and cultural impacts of using GenAI image tools for creative work in Japan. The results indicate that CS graduate students do discuss various ethical and social aspects with GenAI image tools, but many neglected to see how widespread industry usage in Japan has the ability to further marginalize artists in creative workplaces and jeopardize critical aspects of workplace pedagogy in creative industries. This study provides insight into the mindsets of prospective GenAI researchers in Japan and indicates areas of future work that can better prepare them as future knowledge holders and innovators in the field. AI researchers from Canada, Japan, and around the world are encouraged to adopt participatory AI design practices to involve stakeholders throughout the planning, design, and evaluation processes of GenAI image research so they respond to the needs, values, and concerns of artists and creative professionals
EV-based Load-altering Attacks and their Impacts on the Stability of Power Grids
Get PDFThe extensive use of electric vehicles (EVs) provides energy-critical infrastructures with some advantages and drawbacks at the same time. The large-scale deployment of EVs can improve the reliability and efficiency of the power grid through, for instance, bidirectional energy transfers between grids and EVs, reduction in electricity bills, and ancillary services. The majority of these advantages are enabled by the use of communication and information technologies (ICTs) in the EV infrastructures and their associated smart power grids. Moreover, EV supplies equipment (EVSE) network, e.g., charging stations, including a variety of Internet of Things (IoT) devices and smartphone applications that facilitate the charging process for users. However, such a broad deployment of cyber devices and information technologies makes the EV ecosystem prone to cyber-attacks in the form of data manipulation, malware, and intrusions. The attacks against public and private EV charging stations, which are often designed without security concerns in mind, are threats against owners and can lead to complicated security issues for smart grids. Additionally, compromising the security of these large-scale EV infrastructures can propagate into the wide-area transmission power grid, cause resonance events, and result in instability and even blackouts. Studying potentially vulnerable points in the EV ecosystems that adversaries can exploit to impact the stability of power grids, and suggesting proper detection and mitigation strategies is of paramount importance. Finally, designing security metrics for distribution and transmission systems can assist power grid utilities in informing about the power grid security status in the presence of attacks originating from EV ecosystems
Investigating orthogonal interactions between 20S proteasome subunits by humanizing assembly chaperones in Saccharomyces cerevisiae
Get PDFThe proteasome is a large, multi-subunit protein complex essential for degrading unneeded, misfolded or damaged proteins in eukaryotic cells. Mutations in its subunits are linked to many human diseases. How these mutations affect proteasome function remains unclear, so scientists have begun developing a budding yeast (Saccharomyces cerevisiae) model with a fully humanized proteasome to accommodate detailed study.
To date, up to 6 of 7 alpha subunits in the 20S core of the proteasome can be humanized together, all except the α5 subunit, preventing complete humanization of alpha ring in S. cerevisiae. This suggests that yeast chaperones responsible for assembling the 20S proteosome complex may be incompatible with some human subunits (e.g. α5). Thus, to achieve my aim of completely humanizing the alpha ring, I created a set of genetically engineered yeast strains expressing orthologous human chaperones and investigated whether they improved proteasome humanization in yeast.
Results show that human chaperones do not complement phenotypes associated with deleting their yeast orthologs, suggesting they may be incapable of yeast proteosome assembly. Moreover, negative genetic interactions observed between human chaperones and human α5 or β2 subunits suggest these subunits may disrupt yeast 20S assembly. Human chaperone expression failed to permit humanization of α5 in strains harboring partially humanized alpha rings, suggesting that incompatible interactions involving assembly chaperones are not likely responsible for incomplete alpha ring humanization in yeast.
In conclusion, expressing human chaperones in S. cerevisiae failed to overcome barriers preventing complete proteasome humanization, but provided several insights to direct future studies focused on developing this model to study proteasome related diseases
Analyzing the Cryptocurrency Market: Event Studies and Pricing Factors
Get PDFThis thesis investigates the application of event study methodologies and cross-sectional factors in cryptocurrency markets, with a focus on understanding market dynamics and the drivers of cryptocurrency returns. Through two distinct but complementary studies, this work addresses both the methodological challenges of event studies in highly volatile markets and the role of novel factors in pricing ERC-20 tokens.
The first study examines the suitability of traditional event study methodologies in the context of cryptocurrency markets. Given the unique characteristics of cryptocurrencies—such as non-normal return distributions and extreme volatility—the study explores the efficacy of various parametric and non-parametric statistical tests. It identifies non-parametric approaches as more robust, particularly for smaller and highly volatile cryptocurrencies, and highlights the importance of sample size in achieving reliable results.
The second study investigates cross-sectional return predictors in the cryptocurrency market, with a specific focus on ERC-20 tokens. By leveraging both traditional factors such as size and momentum, as well as novel on-chain variables—including transaction value, transfer counts, and active addresses—the study constructs crypto-specific factors that provide deeper insights into token valuation and market behavior. It further demonstrates the relevance of these factors in explaining the variation in token returns.
Collectively, these studies contribute to the growing body of research on cryptocurrency markets by refining event study methodologies and introducing novel factors to better understand market reactions and return dynamics. The findings have broad implications for financial analysis in emerging and volatile asset classes, offering tools for researchers and investors to navigate the complexities of cryptocurrency markets
Change Orders Predictability in Construction Projects and Ways to Improve it – A Data-Driven Study
Get PDFChange orders are formal modifications to the scope of construction projects and play a critical role in shaping project outcomes. However, predicting change orders early in a project's lifecycle remains challenging due to their complex nature and the diverse factors influencing their occurrence. These include project specifications, spatial properties, and the performance of involved actors. Despite extensive research in construction change order management, predictive models for change orders have received limited attention.
This study aims to address this gap by exploring the correlation between project attributes and change order occurrences. It focuses on abstract and easily accessible project attributes such as project type and spatial features, which are more readily shared across the industry. A new set of attributes, derived from domain knowledge, is introduced to quantify project-specific change performance and enhance the prediction of change severity.
The study also tackles the challenge of change timing prediction by modeling the temporal dependence of change orders. Using a Markov Chain approach, it simplifies the relationship between change orders issued in different project phases, assuming each phase’s outcome depends solely on the preceding phase. The validity of this assumption is tested through the Chapman-Kolmogorov equation across projects of varying durations.
Results demonstrate a 15% improvement in change severity prediction performance, highlighting the effectiveness of the introduced attributes and feature selection techniques. The findings also confirm the suitability of the Markov Chain model for capturing temporal dependencies in change orders’ severity, offering valuable insights for early change prediction and better project planning
Semi-Robust Risk Minimizing Hedging Strategies
Get PDFThis thesis explores robust risk-minimizing hedging strategies for contingent claims in incomplete markets with transaction costs, offering a spectrum of tools to balance risk and cost effectiveness. Robust technique applications to finance and insurance have recently gained popularity due to their ability to mitigate model risk. Model risk arises when strategies (or models) become in and out of sync with the market. A model is robust if it can adapt to a wide range of market-dependent factors. However, robust models can be costly and computationally demanding, especially for complex financial and insurance products. Using a multidimensional event tree model, we employ the asymmetric norm as a semi-robust risk measure, integrating asymmetry for customized risk profiles. Three main strategies are developed: a super-replicating approach ensuring full claim coverage at a higher cost, the norm as constraint, which introduces controlled losses to reduce costs, and the norm as objective, minimizing losses directly to enhance capital efficiency. Additionally, self-financing strategies, which require no additional capital injections, offer cost-effective hedging, while portfolio value as state variable strategies allow real-time adjustments, enhancing robustness under volatile conditions. Testing on European call options show that semi-robust strategies - especially norm-constrained and self-financing approaches - maintain low tail risk with minimized cost, demonstrating versatility in adapting to diverse market conditions, investor goals, and risk tolerances while upholding robust risk control
Towards Spatiotemporal Resolution of Copper Aspartate in Gel
Get PDFChiral resolution is essential in the pharmaceutical and food industries, as well as in material engineering, due to the unique properties of enantiomers. This study explores the coordination polymerization of homochiral (L- and D-) and racemic (DL-) copper aspartate (CuAsp) and spatiotemporal resolution of racemic aspartic acid (DL-Asp) using L- and D-proline (Pro)-copper complexes as tailor-made additives (TMAs) via reaction-diffusion frameworks (RDFs) in both 1D and 2D agar gel systems. The imposed supersaturation gradient translates into a gradient of crystal sizes facilitating the formation of CuAsp coordination polymers with spherulitic morphology. Solid-state circular dichroism (CD) and powder X-ray diffraction (PXRD) analyses confirmed the chiral nature and crystalline phases of the CuAsp polymers, with DL-CuAsp forming as conglomerates. Drawing inspiration from Kaoru Harada’s seminal work on the resolution of DL-Asp using L- and D-Pro-copper complexes, the preferential crystallization with ‘rule of reversal’ was evident, where the crystalline CuAsp near the liquid-gel interface exhibited the opposite configuration to those of the TMA. Variability in chirality was noted further from the interface due to concentration gradients. These findings underscore the utility of RDF coupled with the rule of reversal in chiral resolutions, offering an effective strategy for enhancing enantioselectivity in racemic compounds across various applications