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Bioenergy Crop Production: Implications for Grassland Bird Communities in Southwestern Nebraska
No full textBiofuel and bioenergy systems are components of most climate stabilization pathways to reduce greenhouse gas emissions and limit global warming. Currently, corn (Zea mays) is the predominant feedstock used for bioenergy production in the United States. However, widespread production of this monoculture crop has resulted in many negative environmental impacts. The most notorious impact has been the loss of grassland habitat due to agriculture expansion which has had detrimental effects on wildlife that depend on grassland habitat. One such group, grassland birds, has faced steeper, more consistent, and more widespread declines than any other avian guild. Therefore, strategies to protect this imperiled group are of great importance to conservation managers within the Great Plains. Producing Switchgrass (Panicum virgatum) and other perennial grasslands as a bioenergy feedstock is one strategy that could increase grassland habitat and support renewable fuel goals. Among its many ecological benefits, bioenergy perennial grasslands have the capacity to support avian communities. However, in field characteristics and landscape context may influence the suitability of these grassland as avian habitat. We used traditional methods (i.e. point count surveys) and innovative technology (i.e. passive acoustic monitoring) to assess avian populations in perennial grasslands and croplands in southwestern Nebraska in 2021-2023. This research indicates that perennial grasslands support greater overall avian species richness, including higher richness of grassland obligates and species of conservation concern, compared to croplands. Also, integrating bioenergy grasslands on marginal agricultural lands can connect existing grassland patches, expand habitat and benefit area-sensitive bird species. The use of passive acoustic monitoring (PAM) offered a more comprehensive understanding of avian use of perennial grasslands, and we developed an effective method for analyzing acoustic data to draw reliable ecological conclusions. Qualitative interviews were conducted to identify themes that would inform the development of educational materials and conservation messaging aimed at promoting conservation actions. This study demonstrates that it is possible to protect threatened wildlife species and support human needs simultaneously, fostering a more holistic agriculture landscape for future generations.
Advisor: Andrew R. Littl
Detection of Activity Cliffs Produced by Anti-cancer Drugs and an Algorithm for Reliable Predictions in Affected Areas
No full textAn activity cliff (AC) occurs when drugs close in chemical space produce dissimilar biological results. We focus on developing an inferential procedure to detect the presence of ACs in a chemical landscape. If detected, we provide a distance-based procedure that can be used to identify regions of stability in the chemical landscape of interest and generate prediction with higher precision in those areas of stability. We conceptualize the chemical landscape as a spatial random field and use spatial models for prediction of efficacy for new drugs based on “distance” in chemical space. We argue that an AC manifests itself by inducing non-stationarity in the foregoing spatial random field. We utilize a formal non-parametric test of stationarity to detect the presence of ACs. If non-stationarity is detected, a metric-learning algorithm is employed to transform the coordinate system of the original random field. Once completed, the data are retested for stationarity. If the transformed random field is stationary, then ordinary kriging is used for predictions of test points. We show that the precision of the prediction can be further improved by generating convex clusters in the chemical landscape and training cluster-specific spatial models. Finally, we use Euler-Bernoulli beam theory to attach uncertainty to test points that fall outside all clusters.
Advisor: Souparno Ghos
Not the “Mere Creature” of Big Tech: The Constitutionality of Parental Consent Laws for Minors’ Social Media Accounts
No full textA growing number of states have passed laws requiring social media platforms to obtain parental consent before granting accounts to minors to combat rising mental health issues, cyberbullying, and screen addiction. Although well intentioned, every such law has been enjoined in the lower courts, and the Supreme Court has yet to address whether laws requiring parental consent for minors’ social‑media accounts violate the First Amendment. This Comment argues that lower courts have miscast such statutes as content‑based speech restrictions requiring strict scrutiny under Brown v. Entertainment Merchants’ Association. Parental consent laws differ from the content-based statute at issue in Brown. Moreover, when analyzed at the function level, parental consent laws regulate non-expressive functions, not speech itself. Therefore, parental consent laws should face intermediate scrutiny.
This Comment explores how parental consent laws pass constitutional muster while providing parents with a tool to protect minors online. Part II surveys several parental consent statutes and their mechanics. Part III reviews the existing First Amendment precedent in minors’, parents’, and platforms’ speech rights and examines the recent district‑court decisions on parental consent statutes. Part IV explains how the Supreme Court could distinguish parental consent laws from Brown v. Entertainment Merchants’ Association and uphold parental consent laws as content-neutral by analyzing them at the function level. Lastly, Part V outlines the First Amendment considerations legislatures should consider when drafting a parental consent law
Exploring Factors Influencing Student Growth in Mathematics: Elementary Teacher Instructional Practices, Beliefs, and Professional Development Experiences
No full textHigh-quality student learning experiences in mathematics rely on effective teaching. This mixed methods study investigates how elementary teachers’ instructional practices, beliefs about mathematics teaching and learning, and professional development experiences relate to student mathematics growth in a large urban district. Quantitative survey data were analyzed to examine relationships among these factors and student growth outcomes, while qualitative data complemented and deepened the measurable findings. This study builds on prior research on instructional practices and professional development effectiveness by integrating constructs typically examined separately and identifying multiple teacher-related factors that distinguish classrooms with high student growth from those with low growth. The findings and discussion offer evidence to support school and district leaders as they work to improve student growth and achievement in mathematics through the design of impactful professional development. The results may also contribute to policy and practice by clarifying which factors and experiences most strongly align with student growth.
Advisor: Taeyeon Ki
Developing a Metabolic Engineering Chassis from a Metabolically Versatile Organism, \u3cem\u3eRhodopseudomonas palustris\u3c/em\u3e CGA009
No full textMetabolic engineering has made it possible to develop biological processes that were once considered economically unfeasible or uncompetitive. This field has enabled both a robust niche market, whereby products, such as pharmaceutical substances like monoclonal antibodies, are produced exclusively through biological means, as well as an emerging commodity production market. Nonetheless, significant challenges remain in harnessing the unique metabolic capabilities of genetically non-tractable organisms. This dissertation focuses on Rhodopseudomonas palustris CGA009 as a potential chassis for metabolic engineering. To address the issue of genetic intractability, a synthetic biology toolkit was developed to facilitate the expression of heterologous proteins in R. palustris. Leveraging its unique capacity to degrade lignin, a multi-omics approach was employed to explore ligninolytic pathways and identify key enzymes involved in processing different lignin-derived feedstocks. The most significant finding is the hypothesis that R. palustris employs a shared catabolic pathway, utilizing the same set of enzymes to degrade all three major lignin types—H, G, and S. This work also covers the construction of an optimized plasmid-based expression system for R. palustris. This organism\u27s potential application in bioremediation was also assessed, revealing its ability to remove 44% of a 50 ppm dose of perfluorooctanoic acid. Finally, the plasmid retention effects of a relaxase-like mobilization protein, MobV, on R. palustris were investigated. Collectively, this research enhances the ability to metabolically engineer R. palustris, laying the groundwork for its broader application in sustainable biotechnology.
Advisor: Rajib Sah
Defending the Homeland: An Archaeoethnodemographic (AED) Analysis of Population Dynamics and Settlement Patterns in the Navajo Dinétah, AD 1720–1745
No full textThis dissertation presents an innovative archaeoethnodemographic (AED) analysis of Navajo population dynamics during the Middle Period (AD 1720−1745) of the Gobernador Phase in the Dinétah, the ancestral Navajo homeland in northwest New Mexico. During this critical quarter-century, intensified Ute and Comanche slave-raiding and Spanish military expeditions forced the Diné to abandon traditional dispersed settlement patterns in favor of defensive aggregation around fortified pueblitos—small masonry defensive structures built on boulder-tops and mesa-rims throughout the region.
The study employs an AED framework that systematically integrates archaeological site analysis, ethnographic household organization data, historical documentation, and demographic modeling to reconstruct population dynamics during this transformative period. This multi-source approach addresses three fundamental challenges that have limited previous demographic studies: determining site contemporaneity, establishing culturally appropriate household sizes, and reconciling conflicting evidence from archaeological and historical sources.
Archaeological analysis documents 64 pueblito sites (47 Interpueblito community sites and 17 non-community sites) and 183 associated hogans across eight Interpueblito communities, representing the largest concentration of defensive construction during the Gobernador Phase. Using ethnographically-derived household sizes of 4.0−5.5 individuals per dwelling—adjusted for crisis-period demographic conditions—the analysis yields population estimates of 800−1,200 individuals during peak occupation periods.
These estimates receive validation through triangulated approaches: depopulation projections from documented 1865 census data (793 individuals) and 1785 Spanish colonial records (773−966 individuals) converge remarkably with archaeological evidence. The study critically evaluates Naroll\u27s Constant, demonstrating its limitations when applied to circular structures like Navajo hogans, and establishes ethnographic analogies as more reliable demographic indicators.
The findings reveal hierarchical community organization rather than egalitarian settlement distribution, with demographic concentrations varying from 16−22 individuals in smaller communities to 244−336 individuals in major centers like San Rafael Canyon. This research provides essential demographic baselines for understanding Navajo cultural transformation during defensive aggregation and territorial consolidation. At the same time, the AED framework offers a replicable methodological approach for population reconstruction in other contact-period contexts where multiple data sources intersect.
Advisor: Carrie Heitma
A Temporal Extension of Tasselnet with Uncertainty Quantification Using Bayesian Latent Autoregressive Model
No full textManual counting of maize tassels remains a time-consuming and labor-intensive process. Automating tassel counting using maize field images has received significant interest, with researchers exploring methods to streamline this task. Accurate tassel detection can substantially reduce both time and labor costs, offering a practical solution for large-scale agricultural management. Current studies in this area predominantly focus on training object detection algorithms to enhance prediction accuracy and efficiency. Images for this task are often captured in sequences, meaning they capture the exact location of the maize fields over time. However, existing tassel detection and counting methods typically ignore this sequential nature, assuming independence between images. In our work, we propose a Bayesian latent AR process model to accurately forecast tassel densities in these image sequences while quantifying the uncertainty in the predictions. Our method leverages established ideas from local count regression approaches for tassel density prediction, adapting these principles to develop a feature extractor within a transfer learning framework. We then train a latent AR process model with Bayesian inference techniques to effectively capture the associations within image sequences of maize fields. We next extend our work to a case when some of the images in the image sequence are missing. We introduce a two-stage framework, where some representations for the missing images are constructed first, and then a Bayesian modeling framework is invoked on the existing and constructed feature representations to forecast tassel densities in a sequence of images. We also compared the performance of the proposed modeling frameworks against some reliable baseline models that heavily rely on deep learning. The results demonstrate that our method not only outperforms the baselines but also provides reliable uncertainty quantification to support informed decision-making.
Advisor: Souparno Ghos
Thinking Beyond Ourselves: Using Interdisciplinary Exploration and Speculative Scenarios to Understand the Human Experience
No full textThis essay presents an interdisciplinary seminar in honors that challenges students to move beyond the limitations of human experience and examine cognition and behavior across species, environments, and hypothetical extraterrestrial minds. A Choose Your Own Adventure structure encourages reflection on cognitive biases, thereby fostering a nuanced understanding of intelligence, perspective, and sociality. Author observes that students benefit from frameworks that disrupt human-centered biases and suggests that engaging students in speculative scenarios prompts confronting and questioning assumptions about intelligence, ethics, and social dynamics
An Updated Annotated Checklist of the Mammals of the Crane Trust, Hall County, Nebraska
No full textThe Crane Trust is a regional nonprofit conservation organization that has protected land in the biologically important Central Platte River Valley for over four decades. A mammal inventory was conducted on the Crane Trust’s main habitat complex in 1980. Since, a variety of environmental conditions have shifted locally, regionally, and globally. An analysis of the mammal community was conducted using past and recent data to determine how species composition and relative abundance have shifted categorically from 1980 to 2021. We used all available data to categorize relative abundance during two distinct time periods per a modified “DAFOR” scale including 7 total categories: dominant, abundant, frequent, occasional, rare, incidental, and not detected. We then discuss the potential drivers of that community change and their implications for regional conservation programs. Fifty-two mammal species have been identified on Crane Trust property since 1980, with 19 of them being new detections since 2011. However, this discrepancy in species richness over time is likely driven, in part, by the fact recent sampling efforts were more intensive. A handful of species did not change in abundance per our ordinal ranking system (n = 9). Several species shifted slightly, moving just one abundance category (n = 32). However, a moderate number of species shifted relative abundance significantly and changed by more than two ordinal categories (n = 10). Significant decreases in abundance were more commonly seen with species that occupy prairies. Notable increases in abundance were commonly seen with woodland and wetland species. These shifts may reflect local success in wetland restorations, regional woody encroachment, and regional declines in grassland quality and quantity
Eastern Kentucky University: Program Profile
No full textEastern Kentucky University (EKU) is a public comprehensive university in Richmond, Kentucky, with around 15,000 (primarily residential) students. The university offers 80 undergraduate majors, 36 master’s degrees, and four doctoral programs. Approximately 40 percent of undergraduates are first-generation students. EKU traditionally draws many students from its 22-county service region across southeastern Kentucky, but the university also recruits heavily in the larger metro areas of the region