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The Consequences of Connectivity : Informing Fish Passage and Restoration Decisions with Decision Analysis
No full textThesis (Ph.D.)--Michigan State University. Fisheries and Wildlife - Doctor of Philosophy, 2024Dams have dramatically altered riverine systems and are a major contributor to native fish population declines. Dam removal is now a common stream rehabilitation practice in the United States; however, many dams serve important ecological, social, and economic functions, such as flood control, invasive species control, and provision of recreational opportunities. Therefore, dam removal is often contentious among stakeholders and involves making tradeoffs among multiple competing objectives. Decision makers benefit from a thorough evaluation of the ecological, economic, and social consequences and tradeoffs of changes to connectivity using decision analysis and predictive models, yet few examples exist in the literature. The objectives of this research were to use a decision analytic framework and predictive models to evaluate the ecological, economic, and social consequences and tradeoffs of enhancing connectivity for migratory fishes in the Great Lakes basin. In Chapter 1, I used structured decision making to engage a diverse group of stakeholders and rightsholders to evaluate the ecological, social, and economic consequences and tradeoffs of enhancing connectivity for migratory fishes in the Boardman-Ottaway River watershed. The optimal management alternative was passage of native fishes only; however, the optimal alternative varied based on the weight stakeholders might place on each objective. Four weighting scenarios were developed to evaluate the change in optimal management alternative with changes in objective weights. In Chapter 2, an individual-based model framework was developed to forecast the response of migratory fishes to changes in connectivity and applied to predict the change in abundance and growth of six species under various fish passage scenarios on the Boardman-Ottaway River. Population response to barrier removal was species-specific and varied based on initial population size and distribution within the watershed, the number of fish passed upstream, and species life history traits. Species that were found only below the barrier prior to removal benefitted most. Non-native species were found to have greater production potential than native Great Lakes basin species under full passage scenarios. In Chapter 3, I evaluated stocking scenarios for lake sturgeon Acipenser fulvescens to aid decision making in the rehabilitation of an imperiled native Great Lakes basin species. Using the model from Chapter 2, several lake sturgeon stocking scenarios were simulated to forecast the potential time to reach a recovered lake sturgeon population. Sensitivity analysis and expected value of perfect information were used to elucidate key areas of uncertainty. The median time to reach the target abundance was estimated to take between 31 and 91 years, depending on the stocking strategy. The results of this research will help inform decision-makers in the Great Lakes basin on management alternatives for fish passage and restoration that are preferred by stakeholders and that are likely to achieve their objectives.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
JUSTICE AND REPRESENTATION AT A FORMER HERITAGE PLANTATION SITE : UNPACKING SUCCESSES, CHALLENGES, AND PITFALLS
No full textThesis (M.S.)--Michigan State University. Community Sustainability-Master of Science, 2024This study investigated a former plantation site, Arlington House, the Robert E. Lee Memorial (former confederate general), located in the current-day Arlington National Cemetery in Washington, D.C. The National Park Service (NPS) has managed this site since 1933. The house and site are named after R. E. Lee though the structures were built and maintained throughout much of its pre-NPS history by enslaved peoples. Arlington House is a cultural and historical heritage site that has a layered and complex history with multiple narratives of place. On-site interpretation at Arlington House (e.g., information placards, ranger interactions) has shifted recently from interpreting solely the story of Lee to include also interpreting the lives of the formerly enslaved peoples. This 5-chapter thesis used three different methodologies to better understand the site. The first chapter outlines the context of the site and the program of research. Chapter two delves into understanding how this shift in interpretation has been received by the descendants of the enslaved Africans, via two focus groups conducted in summer 2023. Chapter three details an administered on-site visitor survey (n=263) in fall 2023 on visitor heritage identities, expectations, and experiences. Chapter four covers interviews with interpretative rangers at the plantation site in winter 2023/2024 to better understand how they relay the stories of those who were enslaved. These findings are relayed through the concept Black Abstraction which depicts Black people in an abstract context by removing their humanity and feelings of empathy. The final chapter, chapter 5, reviews main findings from each paper and details contributions to theory and managerial recommendations.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Climate change impacts on the hydrology of the great lakes basin and societal implications
No full textThesis (M.S.)--Michigan State University. Environmental Engineering - Master of Science, 2024The Great Lakes Basin (GLB) in North America is home to over 30 million inhabitants and contributes more than 6 trillion dollars to the US GDP annually. Of which, ~20% is generated from agriculture, making it the 2nd largest primary sector in the region\u2019s economy. Thus, understanding the long-term impacts of climate change on the GLB hydrology is crucial for ensuring the well-being of its people, economy, and environment. In this study, I investigate the impacts of climate change on the hydrodynamics of the GLB by analyzing (1) historical data and (2) projected future conditions. The CaMa-Flood model, a high-resolution (~5km with flood attributes downscaled to ~90m) hydrodynamics model, is forced by combinations of different hydrological and global climate models from various sources to simulate future conditions under 3 socioeconomic development pathways, combinations of Representative Concentration Pathways and Shared Socioeconomic Pathways (RCP 2.6-SSP1, RCP 4.5-SSP3 and RCP 8.5-SSP5) over an 85-year period (2015-2100). Historically observed data from 254 USGS stream gauge stations showed that 87.8\% showed an increasing trend in water volume over the past 25 years, which has been linked to changes in precipitation, snow-melt timing, and increased magnitude and frequency of hydrological extremes including floods and droughts. Simulation results suggest that this trend is likely to continue into the future. First, substantial changes are expected in the seasonal hydrologic regime throughout the GLB, especially a major shift in the timing of peak flows from spring to winter, by up to a month in some areas by the end of the 21st century. Furthermore, results also suggest an overall increase in water balance, indicated by an increase in mean surface water storage by up to 20% in some areas. This is also reflected by an increase in lake water levels. Moreover, the frequency of extreme floods increases by 400-2000\% under all climate change scenarios by the late century, especially SSP3 and SSP5. This study provides a comprehensive analysis on the impacts of climate change on the hydrology of the GLB, allowing for the anticipation and design prevention of future devastating hydrological events.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Measuring responses to threatening anti-electronic cigarette messages, subsequent message recall, and vaping intentions
No full textThesis (Ph.D.)--Michigan State University. Communication - Doctor of Philosophy, 2024Prescriptive health messages frequently have limited success in changing minds, especially when perceived as threatening to a target audiences\u2019 autonomy or sense of self. To understand the gaps of when health messages have adverse effects, this study uses reactance theory and limited capacity model for motivated mediated message processing framework to identify how message language directs resource allocation during encoding and how such language affects perceived message effectiveness, message recall, and behavioral intentions over time. Results across two studies, a lab experiment collecting electroencephalography (EEG) data (n = 30) and a national online survey using MTurk (n = 111) demonstrated that participants exposed to experimentally controlled anti e-cigarette messages with freedom threatening language experienced more reactance, increases in e-cig use intention and decreases in health information recall, despite no differences in ERP responses and self-reporting that freedom threatening messages were more effective relative to non-freedom threatening messages. Updates to these bodies of literature reactance permanence and language effects on resource allocation were discussed, as well as practical implications for better persuasive health message strategies.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
EMPIRICAL ESSAYS IN DIGITAL MARKETING
No full textThesis (Ph.D.)--Michigan State University. Business Administration-Marketing-Doctor of Philosophy, 2024ABSTRACTThe heightened usage of social media and other digital platforms in the modern age has generated a large number of interesting and impactful questions for business academics and practitioners. Consequently, marketing scholars have sought to utilize the tremendous amounts of data available in the digital domain to better understand the behaviors of various stakeholders within these arenas. As such, I present two essays aimed at addressing questions housed in the digital marketing space. The first essay considers how the introduction of providing the ability to display mid-roll advertisements (MRAs) on a live streaming platform affects viewing consumption. Utilizing a difference-in-differences estimation approach, the results surprisingly indicate that the introduction of MRAs increases audience consumption. This study also provides evidence of the mechanisms, suggesting that streamers make strategic adjustments to increase viewership after the introduction of MRAs to collect ad revenue. The second essay explores how dark humor and slang usage in social media text impacts virality by examining data from a social and digital media site. By employing a number of tools such as content analysis and topic modelling (via Latent Dirichlet Allocation) in conjunction with a fixed effects approach, this essay provides evidence that social media posts containing dark humor are more viral than those without it, despite the controversial nature of dark humor. Conceptually, we posit that knowledge of the specific context is required to value dark humor. This relationship is further compared against informative versus persuasive posts, finding that the effects of dark humor are generally stronger for posts which are persuasive. This essay simultaneously explores internet slang, suggesting that the use of internet slang is also positively related to virality. The findings from both essays should be of interest to both researchers and practitioners.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Characterize Human Exposure to Per- and Polyfluoroalkyl Substances (PFAS) from Local and Homegrown Foods in and near PFAS-Impacted Sites
No full textThesis (Ph.D.)--Michigan State University. Food Science-Environmental Toxicology - Doctor of Philosophy, 2024Poly- and perfluoroalkyl substances (PFAS) are a group of persistent, toxic chemicals used in many consumer products. They get released into the environment during their manufacture, use, and disposal resulting in the contamination of surface and groundwater, aquatic and terrestrial organisms, sludge (biosolids), soils, and some compost. This has led to PFAS being found in the blood of most people, with some of the highest levels among people with contaminated drinking water or occupational exposures. Exposure to PFAS can have detrimental reproductive, developmental, liver, kidney, and immunological effects. While drinking water is the dominant exposure pathway for those with contaminated water, contaminated food is likely the primary exposure pathway for the general population. Known dietary sources of PFAS include ingestion of foods from grease-resistant paper packaging such as microwave popcorn, fish, and wildlife harvested from areas impacted by local contamination of surface and drinking water. Elevated PFAS concentrations in meat, eggs, dairy products, fruits, and vegetables have also been reported, indicating a need to investigate exposure pathways for livestock and produce in areas near fluorochemical production plants and/or contaminated sites. Therefore, we aim to characterize human exposure to PFAS from foods in and near PFAS-impacted sites in Michigan. Our overarching hypothesis is that PFAS-impacted sites will contribute to elevated concentrations in foods and human dietary exposure. This project will advance our understanding of human dietary exposure to PFAS from impacted sites. Specifically, we investigated these questions at two sites. One is an agricultural cornfield (Chapter 2) we investigated the variability in bioaccumulation for corn kernels grown in soil impacted by PFOS-impacted biosolids ( 64 2100 ng/g-dry weight of PFOS) by first estimating kernel concentrations using the range of literature-derived BAFs and then directly measuring kernel concentrations. Our overall findings indicate that corn kernels accumulate little to no PFOS under certain field conditions, even when soils are highly contaminated with PFOS. Also, inaccurate measurement of PFAS in food may contribute to high variability in BAFs and such variability can result in substantial uncertainty in exposure and risk assessment. For the other two chapters, we investigated a community with high levels of PFAS in drinking water (>1,000 ppt) due to the historic use and disposal of laminated paper products from a former paper mill. Food produced at local farms (Chapter 3) was collected to compare PFAS concentrations in foods near the contaminated site with background. Overall, our results indicate that even seasonal ingestion of foods produced near PFAS-impacted sites can increase dietary PFAS exposure. The Site egg composite contained predominantly PFOS whereas produce was predominant for other PFAS with the highest concentrations in foods with higher water content (e.g., squash and leafy greens). While Total PFAS was highest in Site eggs, exposure for toddlers was highest for squash due to its higher consumption rate among that age group. Also, biological, and environmental samples such as drinking water, garden soil, produce, and other local foods (Chapter 4) were collected from homes in the community. Additional food and soil samples were collected from non-impacted areas. We estimated dietary exposure to PFAS via the homegrown, locally captured, and home-raised for individuals in a community with historically contaminated drinking water. We found that this pathway can be an important ongoing source of exposure less than the drinking water pathway. The concentrations of 40 PFAS were measured in all the biological and environmental samples using high-performance LC-MS/MS and human exposure was estimated for the impacted and non-impacted areas in Michigan. The overall goal of this project is to advance our understanding of the impacts of PFAS on human exposure from contaminated soil and uptake into foods near impacted areas.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
A STUDY OF ADVANCED IGNITION SYSTEMS FOR SPARK IGNITED INTERNAL COMBUSTION ENGINES
No full textThesis (Ph.D.)--Michigan State University. Mechanical Engineering - Doctor of Philosophy, 2024Research into technologies directed towards the improvement in the efficiency of the internal combustion engine has been motivated over the past several years by the regulation of the United States automotive market to more stringent standards for fuel economy and emissions. Lean burn operation of spark-ignited (SI) internal combustion engines may have the potential to help meet the high fuel economy goals of the future decade by improving the efficiency of SI engines at partial loads. Although gains in efficiency are found for engines operating with diluted mixtures, these mixtures present difficulties that manifest themselves through the slow flame speeds and poor ignitability associated with lean or diluted air-fuel mixtures. Two types of ignition systems are examined here that attempt to mitigate these negative effects. They are a radio-frequency plasma-enhanced ignition system and a pre-chamber-initiated ignition system called Turbulent Jet Ignition.First, the effects of a plasma-enhanced ignition system on the performance of a small, single-cylinder, four-stroke gasoline engine are examined. Dynamometer testing of the 33.5 cm3 engine at various operating speeds was performed with both the engine\u2019s stock coil ignition system and a radio frequency plasma ignition system. The radio frequency system is designed to provide a quasi-non-equilibrium plasma discharge that features a high-voltage pulsar that provides 400 mJ of energy for each discharge and voltages of up to 30 kV. Tests show improvement in the engine\u2019s combustion stability at all operating conditions and the extension of the engine\u2019s lean flammability limit with the radio frequency system. Particular attention is given to the improvements that the radio frequency system provides while burning lean air-fuel mixtures. Additionally, analysis of the 33.5 cm3 engine\u2019s exhaust and high-speed images of the radio frequency system taken in a separate 0.4-liter optical engine are also presented. Second, fully three-dimensional computational fluid dynamic simulations with detailed chemistry of a single-orifice turbulent jet ignition device installed in a rapid compression machine are presented. The simulations were performed using the computational fluid dynamics software CONVERGE and its RANS turbulence models. Simulations of propane fueled combustion are compared to data collected in the optically accessible rapid compression machine that the model\u2019s geometry is based on to establish the validity and limitations of the simulations and to compare the behavior of the different air-fuel ratios that are used in the simulations. In addition to being compared to a companion experimental study, investigations into the effect of TJI orifice size and pre-chamber spark location are performed. The data generated in the simulations is analyzed and insights into the processes that make up the operation of the TJI are given. Finally, CFD analysis tools are applied to the early development and design of a TJI system intended for a heavy-duty diesel engine being converted to run on natural gas.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Doing (It) Right : Writing Center Consultants' Re-Entextualization of Language Ideologies
No full textThesis (Ph.D.)--Michigan State University. Second Language Studies - Doctor of Philosophy, 2024Public-facing statements about anti-racism and linguistic justice have become common tools for educational organizations to promote values of criticality and openness. Such statements often explicitly reject practices that equate language difference with deficit and continue to harm marginalized groups that speak languages or use pronouns that fall outside of the \u201cmainstream.\u201d As with all language policies, enacting such statements is far from straightforward as individual social actors bring to bear their own experiences and interpretations of the policy. Drawing on the methodological framework of nexus analysis and theoretical foundations regarding the re-entextualization of language ideologies, this dissertation examines one US university writing center\u2019s language statement as it seeks to decenter English-dominant standard language ideologies and to promote inclusive language practices in the center.In particular, this study highlights how four writing center consultants interpreted and appropriated the statement in diverse ways. Data sources included documents related to onboarding and training, extended semi-structured interviews about consultants\u2019 prior experiences with language difference and consulting practices, audio-recorded observations and field notes of hour-long writing consultations, participant journals, and post-observation reflection interviews. A poststructural, multi-scalar discourse analysis revealed tensions between policy and practice, as well as several profiles of ideological negotiation within the consultants. Discourses valuing competition, excellence, and expertise at the university level came into tension with discourses of relationality and collaboration within the writing center. In response to requests to correct clients\u2019 grammar, consultants developed and revised practices that re-entextualized their past experiences with language diversity as well as the center\u2019s policies about language. The choices to accept or challenge expertise positioning and agree or refuse to make direct edits on clients\u2019 writing were identified as key moments where consultants (re)created discursive relationships between their actions and institutional discourses about language use.Educational institutions seeking to support linguistic diversity through such value-laden language policies should also develop reflective and collaborative tools to assist its members in navigating these ideological tensions. The study lends continued support to using language ideology as an invaluable conceptual tool for administrators and educators interested in grappling with complex social problems.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
DEVELOPING AN INTEGRATED APPROACH FOR LIVERWORT MANAGEMENT IN CONTAINERIZED ORNAMENTAL PRODUCTION SYSTEMS
No full textThesis (Ph.D.)--Michigan State University. Horticulture - Doctor of Philosophy, 2024Weed control is an important management area in containerized production of nurseries and greenhouses because the market value of ornamentals is determined primarily by their quality, appearance, and aesthetics. Liverwort (Marchantia polymorpha) is a notable problematic weed that exists in nursery and greenhouse conditions. It has a flattened thalloid body that forms a mat-like structure on the top of container media. It thrives well in propagation and container production environments with low ultraviolet radiation, high humidity and/or soil moisture, and high fertility. Hand removal of liverwort is a laborious, time-consuming, and costly operation. Not many herbicides are labeled for liverwort control inside greenhouses as most of them can cause severe phytotoxic damage to sensitive ornamentals. Hence, the goal of this research was to develop an integrated management approach for liverwort infestations in nurseries and greenhouses. Various non-chemical methods including organic mulching, strategic fertilizer placements and allelopathic properties of organic mulches; and chemical methods including pre- and post-emergence application of synthetic and organic herbicides were studied for their effects on liverwort control. Absorption and translocation of 14C labeled radioactive 2,4-D and indaziflam in liverwort thallus were assessed by liquid scintillation spectrometry and phosphor imaging. Results indicate that mulching with rice hull and pine bark provided an excellent liverwort control and no phytotoxicity to Hosta spp. varieties \u2018Curly Fries\u2019 and \u2018Pandora Box\u2019. Thicker layers of mulching with cocoa hull and hardwood mulches caused phytotoxicity to \u2018Curly Fries\u2019 and \u2018Pandora Box\u2019, respectively. The sub-dressing and dibble placements of controlled-release fertilizers improved growth of dicot Begonia and monocot Dracaena while minimizing the fresh biomass of liverwort in containerized production. Agar impregnated with maple leaf and shredded cypress mulch based allelopathic extracts showed maximum suppression of liverwort gemmae germination in growth chamber studies. Whereas allelopathic extracts from pine bark and hardwood mulches were most effective for liverwort control under greenhouse conditions. The post-emergence application of glyphosate and 2,4-D at 1X rate and indaziflam at 2X and 3X rates were effective in controlling liverwort. Also, pre-emergence application of indaziflam provided complete inhibition of liverwort gemmae germination and establishment. In the 14C absorption and translocation studies, the total recovery of 14C radiolabeled 2,4-D ranged from 63-80% while it ranged from 49-80% for 14C radiolabeled indaziflam. Phosphor imaging of the translocation samples of liverwort thallus displayed higher movement of 2,4-D as compared to indaziflam in liverwort thallus. The organic herbicide treatments of WeedPharm and Scythe at 2X rate and Avenger at 1X rate provided season-long liverwort control. Overall, a proper utilization of multiple tactics including cultural methods (mulching and strategic fertilizer placement), allelopathy, and chemical methods (pre- and postemergence herbicides) can lead a way to develop an effective integrated control program for liverwort in nurseries and greenhouses.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
FIRST TOTAL SYNTHESIS OF NAGELAMIDE W AND DEVELOPMENT OF NITROGEN CONTAINING HETEROCYCLIC COMPOUNDS AS 20S PROTEASOME MODULATORS
No full textThesis (Ph.D.)--Michigan State University. Chemistry - Doctor of Philosophy, 2024Nitrogen-containing heterocyclic compounds are vital in organic chemistry due to their unique properties and reactivity, playing key roles in pharmaceuticals, agrochemicals, and functional materials. Over 75% of FDA-approved drugs include these heterocycles, underscoring their importance in modern medicine. The discovery of novel N-heterocyclic compounds with significant biological activities is rapidly expanding, driven by advances in synthetic methodologies like transition metal-catalysis and biocatalysis.Looking ahead, the importance of N-heterocyclic compounds is expected to grow. The advent of new technologies and an increasing understanding of disease mechanisms will likely drive the demand for novel pharmaceuticals incorporating nitrogen heterocycles. This trend is anticipated to lead to the discovery of new drugs with improved efficacy and safety profiles, addressing unmet medical needs and enhancing patient outcomes. This dissertation focuses on developing new methods for synthesizing N-heterocyclic compounds, specifically pyrazoles and pyridines, through reactions of epoxides with hydrazine and ammonia, respectively. Both established and novel methodologies were also utilized to synthesize the nitrogen-containing natural product nagelamide W in 11 linear steps, resulting in an overall yield of 6%. Additionally, N-heterocyclic compounds were evaluated as 20S proteasome modulators and used as chemical probes to elucidate their binding sites on the 20S proteasome. These efforts aim to enhance the understanding and application of N-heterocycles in medicinal and biological sciences.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references