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Novel Insights into Lead Corrosion Control: Safely Changing Source Waters, Effective Use of Zinc Phosphate Inhibitors, Electrochemical Reversal of Solder, and Significance of Lead-Polyphosphate Complexation
No full textRecent high profile lead contamination events arising from lead solder corrosion have drawn attention to our alarmingly inadequate understanding of corrosion control chemistry. This dissertation provides novel contributions to an improved understanding of lead corrosion control in four sequential chapters that: 1) develop a new framework to proactively evaluate the impact of source water changes on lead solder corrosion, 2) demonstrate that in certain corrosive waters zinc orthophosphate can dramatically reduce lead contamination from solder at pHs around 7.5-9.5, but is ineffective in relatively non-corrosive waters or at pHs outside this range, 3) reveal that prolonged exposure to free chlorine can dramatically reduce lead contamination from solder by causing "electrochemical reversal," protecting solder from galvanic corrosion, and 4) apply a method for measuring problematic lead complexation by polyphosphate, which reveals a significant health concern in some water chemistries but insignificant problems in others.
Chapter 2 describes how water utilities are increasingly changing source waters in response to groundwater contamination, sustainability efforts, new regulations, and consolidation. We worked with three communities who unexpectedly experienced very severe lead contamination from lead-tin solder following a seemingly innocuous change in source water. We demonstrate how existing frameworks did not anticipate lead solder corrosion problems because: 1) prolonged exposure to non-corrosive water can preserve lead solder in relatively pristine condition, which is more susceptible to severe corrosion following changes in water chemistry, and 2) prolonged exposure to corrosive water can be self-limiting because all exposed lead in copper pipes could have corroded away within a period of decades, counter-intuitively producing low present day lead contamination in a highly corrosive water. A failure to understand the implications of these scenarios resulted in erroneous logic predicting that a source water change would be safe when it was not. We develop a proactive bench scale testing protocol and improved framework that can allow utilities to avoid similar mistakes in the future.
Chapter 3 addresses divergent results regarding the effectiveness of zinc orthophosphate corrosion inhibitor in controlling lead solder corrosion; that is, some research reported remarkable advantages compared to adjusting pH/alkalinity or dosing orthophosphate alone, whereas other research found no benefits. We examined relative performance of zinc orthophosphate at a wide range of pHs (6.5, 7.5, 8.5, 9.5, 10.5) in a low alkalinity, low conductivity water with corrosivity increased by addition of extra chloride or nitrate, and demonstrate that the results depend on water chemistry. Specifically, zinc orthophosphate has little benefit in water with low chloride or nitrate, in which corrosivity is low, at any pH tested. But at higher corrosivity zinc orthophosphate significantly reduced lead release at pH 7.5-9.5, including 40X reductions in lead release at pH 8.5. Yet no relative advantage occurred at pH 6.5 and pH 10.5. Results are consistent with passivation from zinc phosphate precipitation from pH 7.5 to 9.5 as predicted by equilibrium modeling and supported by scale analysis. Similar methods can be used to predict relative performance of inhibitors for controlling lead solder corrosion in other source waters and determine if these results are generalizable.
Chapter 4 explores a 40-year-old mystery with profound present-day implications. A study in Portland, Oregon had revealed that free chlorine had orders of magnitude less lead contamination when compared to chloramine, but the result was discounted because chlorine was always believed to be more corrosive than chloramine. Here, we resolve the controversy by demonstrating "electrochemical reversal" of the copper-solder galvanic couple in synthesized water similar to Portland's. That is, short-term exposure to chlorine did not reduce lead contamination, but prolonged exposure to free chlorine caused the normally anodic solder to become cathodic via formation of a Pb(IV) scale. This eventually caused free-chlorine treated water to have 10-100X less lead contamination than chloramine-treated water after several months of exposure. This discovery has major implications for water treatment and can also help explain why some waters dosed with free chlorine have anomalously low lead contamination.
Chapter 5 examines fears that utilities adding polyphosphates to drinking water to sequester iron and manganese, or to prevent calcium carbonate scaling, will invariably suffer from higher lead solubility and a higher risk of lead contamination. Here, we develop a simple semi-quantitative method using cation exchange resins to evaluate the significance of lead-polyphosphate complexation. Applying this test in a range of waters, we reveal the dependency of lead-polyphosphate complexation on water hardness, polyphosphate dose, and the ratio of orthophosphate to polyphosphate. This approach can be used to predict the impact of a given polyphosphate product and dose on lead complexation, allowing utilities to predict the magnitude of the problem for a given water in about a day. We find a strong linear relationship between polyphosphate dose and complexed lead. Additionally, when >200 mg/L as CaCO3 of calcium is present, >3X less lead-polyphosphate complexation can occur versus when no calcium is present. Our work also demonstrates that testing artifacts probably caused past research to overestimate the danger of the lead complexation problem.
This work has significant implications for public health and is timely as water lead contamination is increasingly scrutinized. The simple tests and corrosion control methods described herein can help drinking water utilities make informed water treatment decisions to reduce lead contamination and protect public health.Doctor of PhilosophyLead is a toxic metal that was commonly used in the drinking water pipes of homes and buildings constructed before 1986. Drinking water can become contaminated by corroding lead as it flows through pipes, threatening the health of consumers at the tap. Lead levels in drinking water have been increasingly scrutinized following severe contamination events in Washington, D.C. and Flint, Michigan. Lead contamination is always highly influenced by water chemistry; the same pipe materials can cause non-detectable lead levels in one community's water, but severe problems in another.
Water utilities are increasingly changing their water sources due to groundwater contamination, concerns about sustainability, efforts to meet new regulations, and consolidation. We worked with several communities who have recently experienced severe lead contamination from lead solder in copper plumbing after changing source waters, and discovered cases in which severe contamination occurred when it was not predicted, and vice versa. To resolve existing erroneous logic and assumptions, we demonstrate that prolonged exposure to non-corrosive water can preserve lead solder in relatively pristine condition, which is highly susceptible to severe contamination following changes in water chemistry. Conversely, prolonged exposure to corrosive water can corrode all of the exposed lead in copper pipes within a period of decades, resulting in low lead contamination today. We develop a new framework and simple test to proactively assess the impact of source water changes on lead contamination from solder and avoid future problems.
Water utilities commonly add chemicals such as orthophosphate to mitigate corrosion by forming protective pipe scales that do not readily dissolve or detach into water. Some utilities have observed profound reductions in lead release from solder in copper plumbing by dosing both zinc and orthophosphate (i.e., "zinc orthophosphate"), although this strategy has been ineffective in other cases. Here, we determine that the effectiveness of zinc orthophosphate depends heavily on the water's pH and corrosivity. Dosing zinc orthophosphate can result in remarkable benefits in corrosive waters from around pH 7.5-9.5, but in other cases it has no advantages whatsoever.
Disinfectants such as free chlorine and chloramine are added to drinking water to kill harmful bacteria and viruses. Here, we determine that prolonged exposure to free chlorine can sometimes dramatically reduce lead contamination from solder compared to chloramine. While this is contrary to the conventional wisdom regarding higher corrosivity of chlorine, we show that in the long term, chlorine can actually protect lead solder from galvanic corrosion by forming a relatively insoluble and highly cathodic Pb(IV) corrosion scale on the solder surface.
Many utilities dose polyphosphate chemicals to water in order limit aesthetic problems with iron and manganese, or to prevent calcium scaling in water heaters and pipes. But there is fear that polyphosphates increase lead solubility and contamination. Here, we present the first simple method to rapidly quantify the impact of polyphosphate on lead release. We then determine polyphosphate can cause problems with lead release in some water chemistries (e.g., soft waters), while minimal problems occur in other cases (e.g., hard waters). This test can be used by utilities to make informed decisions as to when and how, polyphosphate can be dosed without significantly increasing lead in water.
This dissertation has important implications for avoiding public health problems with lead contamination. Water utilities are increasingly changing source waters and water treatment strategies, which can increase corrosivity, and low levels of lead once considered safe are now increasingly viewed with alarm. This work provides a range of tools and research results that can provide a basis for improved decision-making
Automating The Detection and Resolution of Build Conflicts in Software Merge for Java Programs
No full textVersion control systems (VCS) like Git provide an efficient environment for collaborative software development. However, a major challenge of using such systems is the conflicts that occur when developers try to merge branches. This research focuses on build conflicts--a category of higher-order software merge conflicts. The goal of our research is to develop and implement methodologies that automate the detection and resolution process of build conflicts. Our research consists of three pieces. First, we designed and implemented a graph-based pattern matching approach, BUCOND (Build Conflict Detector), to detect conflicts via static analysis. Our evaluation shows that BUCOND accurately identified build conflicts on both synthetic and real-world datasets; it demonstrated great applicability in scenarios where compiler-based tools are inapplicable. Second, we created a hybrid program transformation approach, BuCoR (Build Conflict Resolver), to opportunistically resolve conflicts. We evaluated BuCoR in real-world merging scenarios, observing its great capabilities of generating syntactically correct resolutions and mimicking human developers' resolution practices. Third, we explored a new approach of resolving conflicts using LLMs, and empirically compared the usage of different LLMs as well as diverse prompt designs. We demonstrate that, when properly guided, LLMs can provide highly accurate conflict resolutions. Our research will help developers detect conflicts more efficiently and resolve conflicts with higher effectiveness as well as rigor. Through addressing issues caused by merge conflicts, it will help improve programmer productivity and software reliability.Doctor of PhilosophyVersion Control Systems (VCS) like Git are essential for team-based software development but often struggle with merge conflicts. One complex category of such conflicts is build conflicts. This research aims to make it easier to detect and resolve these conflicts automatically. First, BUCOND, a graph-based tool, has been developed to identify build conflicts, even in scenarios where traditional methods may fail. Second, BuCoR, a program modification tool, has been created to provide automated fix suggestions for build conflicts, often matching what a human developer might do. Third, we investigate the use of Large Language Models (LLMs) for the purpose of build conflict resolution. By advancing the understanding and automation of these processes, this research work aims to improve the efficiency and reliability of collaborative software development
Command and Data Handling-Driven Spacecraft Operations Using Hardware-in-the-Loop Simulation
No full textCubeSats have emerged as a cost-effective platform for space research and technology demonstration, but mission success remains highly dependent on reliable command execution, telemetry handing, and subsystem coordination. Traditional satellite evaluation methods often emphasize isolated subsystem validation or environmental simulation, while providing limited insight into end-to-end spacecraft operations governed by the Command and Data Handling (CandDH) subsystem. The thesis addresses the need this gap by developing and evaluating a COSMOS-based CandDH architecture integrated with the EyasSat educational spacecraft to enable realistic, flight-like command and telemetry operations in a hardware-inthe- loop environment. While attitude determination and control subsystem (ADCS) experiments are used as a representative case study, the primary contribution of this work lies in demonstrating how CandDH-driven command sequencing, mode management, and telemetrytriggered logic can be exercised and validated prior to flight. Experimental results show reliable execution of scripted command sequences, deterministic telemetry-driven responses, and repeatable operational scenarios including payload activation, mode transitions, and closed-loop attitude responses. The integrated EyasSat–COSMOS environment provides a modular and extensible spacecraft operations testbed that shifts validation from isolated subsystem performance toward system-level operational readiness. This approach reduces integration risk, supports operator training, and enables future expansion toward full mission timeline testing involving multiple spacecraft subsystems. The results demonstrate that a low-cost educational spacecraft can effectively support CandDH-centric validation of spacecraft operations, bridging the gap between software-only simulation and flight hardware testing.Master of ScienceSmall satellites known as CubeSats have made space missions more affordable for universities and small research teams. To properly function, however, even these low-cost spacecraft must reliably receive commands, report their status, and coordinate their onboard systems in order to succeed. Many existing testing methods for satellites prior to sending them to space focus on individual components such as navigation or communication, or specific simulated environments such as microgravity or magnetic fields. Such tests can overlook how a spacecraft actually operates as a complete system during a mission. This thesis presents a new way to test spacecraft operations by connecting real satellite hardware to a ground-based control system that mimics how missions are run after launch. Using the EyasSat educational spacecraft and the COSMOS ground software, this work creates a realistic testing environment where commands are sent, response are monitored, and onboard decisions are triggered just as they would be in space.
Although spacecraft pointing experiments are used to demonstrate the system, the main focus of this research is not the attitude control itself, but how spacecraft commands and data are managed as part of normal operations. The test results show that automated command sequences run reliable, the spacecraft responds predictably to changing conditions, and common mission activities such as switching operating modes or turning instruments on and off can be validated before launch.
Overall, the work completed demonstrates that low-cost educational spacecraft can be used to practice and validate real mission operations. By testing how the spacecraft, software, and operators work together, this approach helps reduce mission risk, supports hands-on training, and bridges the gap between simple computer simulations and testing with real flight hardware
Collaborative governance in the face of global change: a social science approach to working effectively at the human-wildlife-environment interface
No full textThis dissertation explores the use of a collaborative governance framework for addressing a range of wildlife and environmental conservation issues. Conservation threats in general are often wide-reaching and interdisciplinary, meaning their impacts extend beyond what one organization or field has the resources and capacity to manage. Collaborative governance, a framework that outlines conditions and stakeholders necessary to work effectively across various boundaries like discipline, scale, and sector, is often used to address such conservation issues because of its ability to overcome such challenges. This dissertation comprises three standalone papers exploring the use of collaborative governance in three separate wildlife and environmental contexts.
The first paper focused on the State Wildlife Action Plan (SWAP) update process in the Southeastern United States leading up to the 2025 submission deadline. Using a qualitative semi-structured interview approach, this study explored how different agencies, organizations, and other entities collaborate to develop plan changes. This study focused particularly on how these plans address the movement of threatened and endangered species across state lines and how they incorporate climate change information as these are expected to worsen in coming years. Findings include the importance of trust, avenues for future collaborations, and the importance of regional agencies.
The second paper explored the development of an ecotourism circuit in Sierra Leone, with a focus on collaboration with local communities. Because tourism development has a strong history of excluding these groups, along with their wants, needs, and concerns, this study focused on assessing these constructs in two potential ecotourism development sites using a qualitative semi-structured interview approach. This ecotourism circuit development represents a unique opportunity to incorporate principles of collaborative governance and community engagement as there is not currently a well-established tourism sector in Sierra Leone. Most work on these concepts in tourism is done retroactively but employing them in Sierra Leone's tourism development can provide valuable information on the benefits and challenges of doing so more proactively. Findings include a desire among all groups for economic and infrastructure benefits, communication challenges between local communities and other stakeholders, and the importance of keeping ecotourism development in Sierra Leone manageable.
The third paper in this dissertation examined the use of the One Health framework in Sierra Leone. This framework emphasizes strong interconnections among human, animal, and environmental health, yet has historically overemphasized human health, particularly zoonotic disease transmission to humans. This imbalance is also present in Sierra Leone's use of One Health, which was formalized immediately after the 2014-2016 Ebola epidemic. The One Health framework, however, has much potential to effectively address other health and safety threats. In fact, expanding its use into other health and safety sectors will be necessary to take the holistic approach to health the framework strives for. This need is especially apparent in places like Sierra Leone, where environmental health threats like climate change, deforestation, urbanization, and natural disasters are rapidly increasing and pose a major threat to health and safety for humans, wildlife, livestock, and the environment. Collaborative governance represents a valuable tool for better integrating these threats and the organizations tasked with addressing them into One Health. This study utilized a qualitative semi-structured interview and focus group approach to explore potential cross-boundary collaborations to initiate or strengthen, challenges to such collaborations, and the most significant health and safety threats. Findings confirm environmental health threats that are rapidly growing, willingness to better incorporate said threats into One Health work, and challenges in putting collaborative plans and policies into action.
Taken as a whole, this dissertation identifies valuable, novel uses of the collaborative governance framework to improve management of threats at the human-animal-environment interface. It explores trends in collaborative governance drivers and challenges, contributing to more effective work in both the specific study settings and in general.Doctor of PhilosophyWildlife and environmental conservation issues are often wide-ranging and require involvement from agencies, organizations, and individual from a variety of backgrounds and fields of study, including but not limited to biology, geography, engineering, policy, and social sciences. Because these fields often deal with different forms of information and address problems in different ways, it can be challenging to align their goals, strategies, and even interpersonal skills like communication methods and conflict resolution. Collaborative governance, a framework that provides guidance on what kinds of groups and individuals are important to include and conditions necessary to make collaborations more successful, can be incredibly useful in such contexts. This dissertation utilizes the collaborative governance framework in three environmental and wildlife management study settings.
The first study in this dissertation focused on State Wildlife Action Plans (SWAPs) in the Southeastern United States. It is comprised of interviews with a range of wildlife planners and professionals on their experience in developing and updating SWAPs, particularly as factors like climate change grow and shift, with potential major impacts on wildlife in the study region. Interviews also explored how various conservation agencies and other organizations work together on these plans, particularly across boundaries like state lines or fields of study. Findings include the importance of trust in collaborations and the role of agencies or organizations dedicated to managing cross-boundary collaborations.
The second study in this dissertation examined ecotourism development in Sierra Leone. It focused on the role and experience of communities located around sites where ecotourism programs are being developed. More specifically, this study focused on what benefits communities would like to see result from ecotourism, their concerns about implementing the programs, and whether they felt meaningfully included in ecotourism planning. Findings include a consistent desire for economic, employment, and infrastructure development (construction of schools, water wells, etc.) as a result of ecotourism and challenges around communications between communities and other organizations involved in the project.
The third study centered on addressing environmental health and safety risks through the One Health framework in Sierra Leone. One Health is an approach that incorporates many different fields of study to address the strong connections among human, animal, and environmental health. However, it typically focuses disproportionately on the human health component and diseases that spread from animals to humans. In places like Sierra Leone, environmental health threats like natural disasters and access to clean food and water are becoming increasingly dangerous. This study examined challenges and opportunities to expanding and strengthening collaborative efforts to address these threats through Sierra Leone's One Health platform. Findings revealed overwhelming willingness to better integrate the environmental sector as well as challenges to doing so.
Overall, this dissertation addresses collaboration across boundaries like state lines, fields of study, and roles in addressing threats and challenges related to environmental and wildlife conservation. It explores trends in what makes these collaborations successful, what is challenging about them, and where they need to be strengthened or initiated in the three study sites. Additionally, results can help inform more general work in these fields, contributing to more effective cross-boundary collaborations in a variety of settings
Energy metabolism in skeletal muscle: mechanistic insights into mitochondrial function and growth
No full textSkeletal muscle metabolism is critical to understanding the efficiency of muscle growth for the global meat industry. As such, there are many contributing factors that can influence muscle growth yet there are still basic molecular mechanisms that remain unexplored. Specifically, the involvement of mitochondria during skeletal muscle hypertrophy. Armed with this goal, we sought to target the fundamental aspects of how the mitochondria facilitate muscle growth in various livestock species. We showed that skeletal muscle mitochondrial abundance through mitochondrial DNA (mtDNA) and protein may not be sufficient to determine their functionality significance in muscle of livestock. Particularly, avian mitochondrial function is independent of absolute mtDNA and protein abundance. However, porcine and bovine muscle mitochondria abundance correlated with skeletal muscle type function. These findings confirm the importance of evaluating mitochondrial content and function to determine their overall contribution to muscle metabolism. To investigate the role of the mitochondria during muscle growth, we utilized beta-adrenergic agonists (BAA) fed pigs harboring the constitutively active adenosine monophosphate activated protein kinase mutation (AMPKγ3R200Q) that results in greater oxidative capacity in a habitually glycolytic skeletal muscle. We discovered BAA supplementation stimulates beta-1 adrenergic receptor gene expression and impacts mitochondrial respiration. Interestingly, BAA feeding had more effect on control pig muscle compared to that of pigs harboring the AMPKγ3R200Q mutation. This further suggests BAA-induced muscle hypertrophy is not as effective on muscles with increased oxidative capacity. To expand our knowledge on muscle hypertrophy, we assessed the impact of finishing feeding regimes on beef cattle muscle energy utilization. We showed that mitochondria from muscle of forage-maintained cattle have greater respiration compared to mitochondria of those carbohydrate-maintained cattle and glycolytic muscles. These data indicate that diet impacts skeletal muscle metabolism specifically in the ability of mitochondria to utilize long- and short-chain fatty acids. In addition to studying muscle hypertrophy in livestock, we generated knockout mouse models to assess the necessity of mitochondria in skeletal muscle during post-weaning growth. We found that reduced mtDNA content has a mild impact on mitochondrial protein expression and functionality, yet appears accumulative in its impact on skeletal muscle as reflected in final body weight and lean mass of knockout mice. Finally, we created a knockout mouse lacking a functional mitochondrial ATP synthase subunit beta gene and found that the ability of the mitochondria to generate ATP was not requisite for post-weaning growth of muscles expressing myosin light chain-1. In summary, mitochondria contribute significantly to overall skeletal muscle metabolism yet may not be required for optimal muscle growth prior to maturity. Further understanding of the molecular mechanisms necessary for optimal muscle growth is necessary to provide additional opportunities to improve efficiency of livestock growth.Doctor of PhilosophySkeletal muscle metabolism is critical to understanding the efficiency of muscle growth for the global meat industry. As such, there are many contributing factors that can influence muscle growth yet there are still basic molecular mechanisms that remain unexplored. Specifically, the involvement of mitochondria during skeletal muscle hypertrophy. Armed with this goal, we sought to target the fundamental aspects of how the mitochondria facilitate muscle growth in various livestock species. We showed that skeletal muscle mitochondrial abundance through mitochondrial DNA (mtDNA) and protein may not be sufficient to determine their functionality significance in muscle of livestock. Particularly, avian mitochondrial function is independent of absolute mtDNA and protein abundance. However, porcine and bovine muscle mitochondria abundance correlated with skeletal muscle type function. These findings confirm the importance of evaluating mitochondrial content and function to determine their overall contribution to muscle metabolism. To investigate the role of the mitochondria during muscle growth, we utilized beta-adrenergic agonists (BAA) fed pigs harboring the constitutively active adenosine monophosphate activated protein kinase mutation (AMPKγ3R200Q) that results in greater oxidative capacity in a habitually glycolytic skeletal muscle. We discovered BAA supplementation stimulates beta-1 adrenergic receptor gene expression and impacts mitochondrial respiration. Interestingly, BAA feeding had more effect on control pig muscle compared to that of pigs harboring the AMPKγ3R200Q mutation. This further suggests BAA-induced muscle hypertrophy is not as effective on muscles with increased oxidative capacity. To expand our knowledge on muscle hypertrophy, we assessed the impact of finishing feeding regimes on beef cattle muscle energy utilization. We showed that mitochondria from muscle of forage-maintained cattle have greater respiration compared to mitochondria of those carbohydrate-maintained cattle and glycolytic muscles. These data indicate that diet impacts skeletal muscle metabolism specifically in the ability of mitochondria to utilize long- and short-chain fatty acids. In addition to studying muscle hypertrophy in livestock, we generated knockout mouse models to assess the necessity of mitochondria in skeletal muscle during post-weaning growth. We found that reduced mtDNA content has a mild impact on mitochondrial protein expression and functionality, yet appears accumulative in its impact on skeletal muscle as reflected in final body weight and lean mass of knockout mice. Finally, we created a knockout mouse lacking a functional mitochondrial ATP synthase subunit beta gene and found that the ability of the mitochondria to generate ATP was not requisite for post-weaning growth of muscles expressing myosin light chain-1. In summary, mitochondria contribute significantly to overall skeletal muscle metabolism yet may not be required for optimal muscle growth prior to maturity. Further understanding of the molecular mechanisms necessary for optimal muscle growth is necessary to provide additional opportunities to improve efficiency of livestock growth
Environmental Science & Technology
No full textDisinfection of drinking water provides essential protection against microbial pathogens. However, disinfectants react with organic matter and other constituents in water to form disinfection byproducts (DBPs), which are of concern for human health. Chlorocyanurates are chlorine-based disinfectants that have been used for drinking water in point-of-use and emergency contexts. Little is known about chlorocyanurate DBP formation beyond the potential to form lower regulated trihalomethanes and haloacetic acids compared to chlorine. In this study, regulated and unregulated DBP formation was evaluated for multiple chlorocyanurate formulations to understand the effect of the chlorine-to-cyanuric acid ratio on DBP mixture composition and calculated toxicity by comparison to conventional chlorine. Chlorocyanurates produced lower regulated DBPs by ∼10-50% compared to chlorine but promoted bromine incorporation in most DBP classes by 50-200% and produced higher calculated toxicity than chlorine under most conditions. Enhanced dichloroacetonitrile formation by chlorocyanurates was partly attributed to trichloramine formation from the degradation of chlorocyanurates by hypochlorite. Thus, chlorocyanurates may promote multiple DBP toxicity drivers. Water quality and operational considerations are identified to minimize DBP toxicity while using chlorocyanurate disinfectants, which remain an important option for drinking water disinfection in low-resource settings.Published versio
<i>Historias</i> for the Empire: Indigenous Translators and the Reproductions of Linguistic Conquest
No full textPublished versio
Macroscopic approximation of tight-binding models near spectral degeneracies and validity for wave packet propagation
No full textThis paper concerns the derivation and validity of macroscopic descriptions of wave packets supported in the vicinity of degenerate points (K,E) in the dispersion relation of tight-binding models accounting for macroscopic variations. We show that such wave packets are well approximated over long times by macroscopic models with varying orders of accuracy. Our main applications are in the analysis of single- and multilayer graphene tight-binding Hamiltonians modeling macroscopic variations such as those generated by shear or twist. Numerical simulations illustrate the theoretical findings
Sustainability
No full textClimate change is a pressing issue that has far-reaching effects on the global ecosystem, societies, and economies. Climate-induced disasters exacerbate multidimensional poverty through economic, social, and environmental pathways. This study examines the relationship between climate-induced disasters and multidimensional poverty, applying a mixed-method design comprising a PRISMA-guided systematic review and thematic analysis. Articles published between 1999 and 2025 were retrieved from Scopus and Web of Science, yielding 3587 articles. After reference checking and screening for relevance and availability, we finally reviewed 17 articles. The results highlight that climate-induced disasters disrupt economic and livelihood activities, negatively impact GDP, slow financial development, reduce per capita expenditure ability, and harm agricultural production. Disasters also have negative impacts on health and well-being, education, gender, the natural environment, and culture; these disasters promote intergenerational poverty. Among all stressors, floods and droughts are the most pervasive, and they have different magnitudes and durations of impacts. The assessment identifies governance quality, gender inequality, education, social positions, and environmental degradation as the significant mediating systems influencing vulnerability and recovery. To cope with vulnerabilities, individuals employ a variety of strategies based on their socioeconomic status. Building on these insights, the study develops the Multidimensional Climate–Poverty Dynamics (MCPD) Framework to conceptually capture climate–poverty as a socially constructed and institutionally mediated process. The study contributes theoretically to environmental sociology and empirically to climate policy by framing adaptation as a social process of transformation rather than as solely a survival mechanism.Published versio
Creating Exercises with Generative AI for Teaching Introductory Secure Programming: Are We There Yet?
No full textDespite ongoing efforts to integrate security concepts into computer science curricula, many graduates still lack practical software security skills. Active learning strategies—such as drill-and-practice— offer a promising approach to bridging this educational gap. To implement these strategies effectively, educators must design and deliver hands-on exercises focusing specifically on secure programming. However, creating effective secure programming exercises is difficult, requiring substantial time and in-depth expertise. This paper examines the potential of generative AI to aid in creating drill-and-practice exercises for introductory secure programming settings. Specifically, we prompt several large language models (LLMs) to assist in generating exercises targeting three common software vulnerability classes, with tasks aligned to the advanced beginner stage of the Dreyfus skills acquisition model. We systematically evaluate the generated exercises for correctness and instructional viability. Our results show that, for some vulnerabilities, LLMs can produce technically sound and useful exercises for advanced beginners. While many generated exercises were near classroom-ready, minor fine-tuning is often necessary to ensure quality and pedagogical alignment. These findings suggest that effective exercise generation in secure programming is best achieved through a symbiosis between generative AI and human educators.Published versio