Digital Commons Network^™

Large-Scale Experimental Study On The Impact Of Air Cleaning & Ventilation On Indoor Air Quality And Student Illness-Related Absenteeism, Daud Nosham

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

This large-scale randomized experimental field study investigated the effect of portable air purifiers (PAPs) on classroom’s air quality and student’s illness related absenteeism. PAPs were installed in 317 classrooms from various school districts located in Eastern Nebraska. The classrooms were randomly assigned into four conditions: three treatment conditions (T1, T2 & T3) and one control condition (device without any filter). T1 was equipped with HEPA filters, T2 added Activated Carbon (AC) layer to HEPA, and T3 further integrated Germicidal Ultraviolet (GUV) alongside HEPA and AC filters. The measured variables were carbon dioxide (CO2), fine particles (PN2.5) and coarse particles (PNcoarse), …

Assessing Crop Rotation Productivity, Soil Health, And Fertility, And Economic Performance, To Enhance Semi-Arid High Plains Cropping Systems Sustainability, Ezequiel Maria Villamil

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Sustainable crop production in the semi-arid High Plains of Nebraska faces challenges from limited precipitation, high interannual variability, and economic risk. This dissertation investigates the long-term productivity, water use, soil health, and economic sustainability of dryland crop rotations, with emphasis on the role of pulses as alternatives to fallow.

Chapter 1 analyzes nearly three decades (1995–2023) of on-farm data from the High Plains Agricultural Laboratory (Sidney, Nebraska) to compare seven crop rotations, including wheat, corn, millet, sunflower, and field peas. Results showed that wheat–corn–fallow (W–C–F) consistently outperformed traditional wheat–fallow (W–F) and more intensified four-year rotations, providing the highest grain yields, …

Advancing Precision Agriculture Through The Application Of Remote Sensing Technologies In Plant Health Assessment, Thomas Wilbur Davis

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Monitoring plant health, including nutritional status assessment, is an important component of crop management decisions. This doctoral document addresses the use of agricultural remote sensing through focused investigations of plant disease detection and nutrient status assessment technologies that advance precision agriculture. The first chapter provides a comprehensive overview of remote sensing technologies in agriculture and examines current capabilities, limitations, and future directions. The final two chapters address studies that evaluated the virus-nitrogen interaction in wheat and compared methods to determine the nitrogen status of midseason field corn.

The first study evaluated the wheat streak mosaic virus (WSMV) × nitrogen interaction …

Detecting Prescribed Fire, Haying And Grazing Events Via Remote Sensing To Create Grassland Disturbance Landcovers For The Ring-Necked Pheasant (Phasianus Colchicus), Megan A. Baldissara

School of Natural Resources: Dissertations, Theses, and Student Research

This dissertation developed disturbance detection models to fulfill the need for remote sensing landcover products describing grassland structure. The use of landcover products derived from remote sensing is increasing over time in pheasant (Phasianus colchicus) research. Such landcover, however, does not provide relevant pheasant structural habitat information (Chapter 1). Pheasants require tall, high-density grassland for nesting, tall grassland with medium density for brood rearing, and tall grassland for wintering. Time since disturbance can serve as a proxy for structure, as it shapes vegetation by removing biomass and resetting succession. Disturbance is easier to detect than structure with current …

On Bayesian Empirical Likelihood-Based Method For Complex Survey Data With Application To Non-Probability Sampling, Md Hasibur Rahman

Department of Statistics: Dissertations, Theses, and Student Research

This thesis develops a Bayesian empirical likelihood (BEL) framework for inference under complex survey designs and extends it to non-probability sampling. Parametric likelihood based methods are difficult to apply to complex survey data because the likelihood is rarely available in closed form. EL provides a flexible alternative by replacing the parametric likelihood with an empirical likelihood constructed from moment conditions. The proposed method first integrates empirical likelihood constraints with survey design features then extends BEL to non-probability sampling through selection models and design consistent restrictions. Posterior inference is carried out using a Metropolis–Hastings MCMC algorithm. A real-data analysis further illustrates …

Modeling The Greenland-Iceland-Faroe Ridge Using Integrated Geophysical Analysis, Zachary Clowdus

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The Greenland-Iceland-Faroe Ridge (GIFR) is an area of significant geologic interest with anomalously thick crust related to enhanced melt generation from the interaction between the Mid-Atlantic Ridge and the Iceland hotspot. To the northeast of Iceland lies the Jan Mayen Microcontinent (JMMC), which is a continental fragment separated from Greenland during the opening of the Northern Atlantic. The overall extent of the JMMC, especially its southern boundary, remains poorly constrained. The crust beneath the GIFR is believed to be primarily of oceanic affinity. However, a recent discovery of felsic lavas in Iceland led to an alternative hypothesis that implies the …

The Urban Heat Island And Its Role In Shaping Convective Environments: An Observational Study, Benjamin W. Moll

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The continued spread of urbanization and its well-documented effects on regional weather and climate necessitate further research. Urban environments are often warmer and drier than their rural surroundings. This trade-off between a warmer but drier environment could have a complex impact on deep convection and its initiation. Previous studies have noted significant changes in precipitation patterns around cities as well as changes to ongoing deep convection. Given the well-documented theory and past research, it is hypothesized here that urban areas have a significant impact on the PBL thermodynamics of convective environments. The urban heat island (UHI) component of the Micro …

A Low-Power Mixed-Signal Potentiostat System-On-Chip With Integrated Dual-Slope Adc, Seth Mcrobert

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

This thesis presents the design and characterization of a low-power mixed-signal potentiostat that was integrated with a 65 nm core in a SoC for low-power electrochemical sensing applications. The system integrates a low-noise transimpedance-based potentiostat front end with a 12-bit dual-slope analog-to-digital converter (ADC) for accurate current-to-digital conversion. The potentiostat core—comprising the control amplifier, current-mirror network, and transimpedance amplifier—consumes 38.2 µA from a 2.5 V supply (95.5 µW) and achieves an input-referred noise floor of 113 µVRMS over a 330 Hz bandwidth, while having an input current range from 1 nA to 20 µA and a noise-limited sensitivity of 56.4 …

Llm-Assisted Cwe Identification, Severity Assessment, And Vulnerability Description Generation, Mohammad Jalili Torkamani

School of Computing: Dissertations, Theses, and Student Research

Identifying the underlying weakness types and assessing their severity using CWE and CVSS standards are critical steps in software vulnerability management. While timely assessment of vulnerabilities mitigates the impact of severe security incidents, automating joint CWE identification and severity assessment remains challenging due to the heterogeneity of vulnerabilities across different code granularities and programming languages. In addition, generating vulnerability descriptions is often time-consuming, as it requires extensive manual review, validation, and writing by security experts.

In this thesis, we leverage the capabilities of Large Language Models (LLMs) to automate the identification of CWE identifiers and the assessment of their severity …

Evaluation Of Distractor Model Specifications On Assessment Quality Within The Framework Of Assessment Engineering, Sunhyoung Lee

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Responding to the high demand for new test items, model-based item development has emerged as a promising approach for efficient item creation. Item models within Assessment Engineering (AE) offer a systematic framework that effectively generates a large volume of new items. In the development of multiple-choice questions, well-constructed distractors are essential for ensuring item quality, although creating them requires significant time and resources. A distractor model is a sub-model within an item model, producing correct answers and distractors aligned with all potential items to be generated. Various types of distractor models have different characteristics and offer efficient methods for generating …

Investigating Programming Behaviors To Understand Student Engagement And Experience In Introductory Programming Courses, Marcus Eugene Gubanyi

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Introductory programming courses are foundational to developing students’ problem-solving abilities and shaping their persistence in computing pathways. Engagement with programming tasks plays a central role in student learning and experience. Many research measures, including self-reports and code submissions, offer only a limited view of student engagement with programming tasks. This dissertation leverages programming process data, consisting of keystrokes and compilation events, to capture the programming process as it unfolds and to investigate observable programming behaviors. Guided by educational theories, three studies examine how students’ programming behaviors vary across instructional and assessment contexts, how they relate to motivational profiles, and how …

Making Deep Neural Networks Trustworthy: Intelligibility And Safety Through Symbolic Methods, Eleanor Catherine Quint

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The rapid adoption of deep learning has come at the cost of properties long valued in artificial intelligence: intelligibility and safety. This dissertation develops methods that restore these properties by coupling neural networks with symbolic structure.

First, for supervised classification, I propose a differentiable decision tree integrated with a supervised variational autoencoder. The resulting model maintains competitive accuracy and generative performance while exposing clear macro-features in its latent space, improving interpretability.

Second, for reinforcement learning, I extend constrained Markov decision processes by specifying constraints in formal languages. This formal language constrained MDP enables the use of automata for state augmentation, …

Modelling Groundwater Nitrate Transport In Bazile Creek Watershed Using Modflow, Prajwol Thapa

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Excessive application of inorganic nitrogen fertilizers has led to pervasive nitrate contamination of groundwater in agricultural regions worldwide. This study evaluates the fate and transport of nitrate beneath the Bazile Creek watershed in northeastern Nebraska by coupling groundwater‐flow (GWF) and solute‐transport (GWT) simulations within MODFLOW 6. A conceptual model was developed using hydrogeologic, topographic, recharge, and boundary‐condition data, and the domain was discretized with a quadtree-refined grid to capture surface-subsurface interactions. The steady-state flow model was calibrated against observed hydraulic heads and baseflow measurements using NSE, RMSE, and PBIAS metrics, and subsequently extended to a transient flow simulation spanning 2002-2023. …

Changepoint Detection As Model Selection: A General Framework, Michael A. Grantham

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

This dissertation presents a general framework for changepoint detection based on ℓ₀ model selection. The core method, Iteratively Reweighted Fused Lasso (IRFL), improves upon the generalized lasso by adaptively reweighting penalties to enhance support recovery and minimize criteria such as the Bayesian Information Criterion (BIC). The approach allows for flexible modeling of seasonal patterns, linear and quadratic trends, and autoregressive dependence in the presence of changepoints.

Simulation studies demonstrate that IRFL achieves accurate changepoint detection across a wide range of challenging scenarios, including those involving nuisance factors such as trends, seasonal patterns, and serially correlated errors. The framework is …

In-Field Tractor Operational Load Profile Generation In Support Of Advanced Tractor Testing In Mixedmode Power, Andrew Donesky

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

This dissertation addresses the need to better characterize real-world tractor power requirements across drawbar, power take-off (PTO), and hydraulic modes to support more representative tractor testing. Conventional testing protocols, such as OECD Code 2, emphasize steady-state performance under controlled high-load conditions, which do not reflect the mixed and dynamic demands of modern field operations. To address this gap, a Tractor Instrumentation System (TIS) was developed, validated, and deployed to collect high-resolution, mixed-mode power data during planting, anhydrous ammonia application, and grain cart operations. The TIS integrates physical sensors, including custom load pins, hydraulic pressure/flow sensors, and a redesigned PTO torque …

Evaluation Of Ramp Instead Of Forage During Grain Adaptation And Different Sorghum Varieties On Enteric Methane Production From Cattle, Jack T. Fort

Department of Animal Science: Dissertations, Theses, and Student Research

Two experiments were conducted to evaluate the use of RAMP (Cargill Corn Milling, Blair, Nebraska) compared with traditional forage-based adaptations on methane (CH₄) and carbon dioxide (CO₂) emissions, performance, and carcass characteristics. Experiment 1, 64 yearling British × Continental steers (initial BW = 423 ± 6 kg) were adapted using 100% RAMP (RAMP) or a traditional forage diet (CON; 43% forage) before transitioning 22 d to a common finishing diet containing 65.6% steam-flaked corn. Emissions were measured in paired replications using a two-chamber indirect calorimetry barn. During adaptation RAMP did not affect CH₄ production (g/d; …

Integrating Innovative Sensing And Ground Measurements For Forage Mass Estimation In Rye Pasture, Pedro Henrique Jota Fernandes

Department of Animal Science: Dissertations, Theses, and Student Research

The United States beef industry relies on forages to provide up to 80% of total lifetime dry matter intake, making accurate forage mass estimation essential for determining stocking rates, improving grazing efficiency, and supporting economic sustainability. Traditional methods to quantify forage mass, however, are time-consuming and labor-intensive. This thesis presents research efforts to achieve accurate forage mass estimation in cereal rye pasture by integrating novel sensing technologies.

Chapter 1 reviews the importance and evolution of forage mass estimation methods, from destructive clipping to indirect approaches based on canopy measurements. It then introduces remote sensing, from proximal tools to drone- and …

Occurrence Of Per And Polyfluoroalkyl Substances In Rural Wastewater Treatment Plants And Comparison To Large Treatments Plants, Madeleine Rauhauser

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Per and polyfluoroalkyl substances (PFAS) are a class of compounds defined by their carbon – fluorine bonds, which are incredibly strong. The strength of this bond makes these compounds very useful industrially, they are used as waterproof and grease proof coatings, and as fire retardants. The same thing that makes them useful industrially makes them incredibly recalcitrant in the environment, it is difficult to destroy these compounds. PFAS are also suspected to cause health impacts in people, such as kidney cancer and low birth weights. Wastewater has been commonly identified as a contributor to the amount of PFAS in the …

Musical Self-Efficacy Through Active Music Listening: A Phenomenological Approach, Amy Marie Fraser

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Music is often perceived as a talent reserved for the naturally gifted, rather than a fundamental human ability. This study questioned that perception by examining how active music listening can develop musical self-efficacy and reshape attribution beliefs about musical ability. Using a phenomenological approach, this study explored the experiences of students in a university music appreciation course, investigating how structured listening exercises, peer interactions, and reflections contribute to their perceived musical beliefs and competence. Grounded in Bandura’s self-efficacy theory and Weiner’s attribution theory, the study considered whether musical engagement can be accessible to all and not limited by perceived talent. …

Detecting Prescribed Fire, Haying And Grazing Events Via Remote Sensing To Create Grassland Disturbance Landcovers For The Ring-Necked Pheasant (Phasianus Colchicus), Megan Amy Baldissara

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

This dissertation developed disturbance detection models to fulfill the need for remote sensing landcover products describing grassland structure. The use of landcover products derived from remote sensing is increasing over time in pheasant (Phasianus colchicus) research. Such landcover, however, does not provide relevant pheasant structural habitat information (Chapter 1). Pheasants require tall, high-density grassland for nesting, tall grassland with medium density for brood rearing, and tall grassland for wintering. Time since disturbance can serve as a proxy for structure, as it shapes vegetation by removing biomass and resetting succession. Disturbance is easier to detect than structure with current …

Securing Connected And Autonomous Vehicles, Owana Marzia Moushi

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

A vehicular network is susceptible to various security flaws and attacks. Cryptographic techniques are used in vehicular networks but these alone cannot provide proper security to the network. Identifying various types of attacks is necessary to secure vehicular communication networks. In this dissertation, we focused on detecting various insider attacks in vehicular networks to enhance the security of the network.

Our first contribution in this dissertation is the detection of both binary and multi-class data replay and data replay Sybil attacks in vehicular networks. A publicly available dataset, VeReMi-Extension is used to detect these attacks. This dataset has been reformulated …

Effect Of Planting Date, Insecticide Efficacy, And Hail Injury On Soybean Gall Midge (Resseliella Maxima Gagné) Infestation In Soybean, Natasha Hiromi Umezu

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Resseliella maxima Gagné (Diptera: Cecidomyiidae) is a recently described and economically significant pest of soybean (Glycine max (L.) Merr.) in the Midwestern United States. Since its identification in 2019, this species has become widespread and is now associated with substantial yield losses in parts of the region. Prior to its formal description, orange larvae were observed in soybean associated with plants damaged by hail, suggesting that plant injury may influence infestation. Given the pest’s economic importance, understanding the role of hail injury and developing effective, integrated management strategies are critical for mitigating its impact.

Field studies were conducted to …

Real-Time, Co-Regulated Design For Cyber-Physical, Multi-Rotor Uas Swarms, Grant Simon Phillips

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Uncrewed Aerial Systems (UAS) have been integrated into a wide range of research and industrial applications, with growing interest in extending mission duration and spatial coverage through coordinated multi-UAS systems, or swarms. While swarming offers the potential for extended mission endurance and robustness through advanced path-planning, control, and estimation algorithms, significant challenges arise when implementing these methods on decentralized platforms composed of size, weight, and power-constrained (SWaP) vehicles. Limitations in onboard computational capacity and congested communication channels can break critical design-time assumptions, which at best, will degrade application quality of service, and at worst, destabilize the fleet through excessive delays …

Art Teams Year 4 Annual (Ad Hoc) Report 2024-2025, Guy Trainin, Kimberley D'Adamo, Hyeonjin Yoon, Azadeh Hassani, Zohreh Tamimdari, Jiabin Lyu, Michael Nti Ababio, Sarah Trainin

Research and Evaluation in Education, Technology, Art, and Design

This report documents the fourth year of the Art TEAMS project, a multi-year professional learning initiative focused on arts-integrated, transdisciplinary teaching practices across Nebraska K-12 schools. During the 2024-2025 academic year, the project advanced work with its second cohort of educators while maintaining engagement with the first cohort to assess the sustainability of implementation. The second cohort brought increased diversity in art forms, including ceramics, digital media, and career and technical education, demonstrating the versatility of arts integration across curricula.

Year Four activities included delivering refined professional development courses grounded in emergent curriculum design, with significant curriculum modifications based on …

Flea News 96 (November 2025), R. L. Bossard

Flea News

Flea News is a twice-yearly newsletter about fleas (Siphonaptera). Before including in publications any of the citations given here, please review for accuracy and correct formatting. Many of our sources are abstracting journals and current literature sources, and editors have not necessarily checked citations.

Announcements

Obituary: Lane Douglas Foil (June 16, 1949 - June 22, 2025)

Siphonaptera Literature (2025): Taxonomy, Conservation, Hosts and Distributions, Physiology and Morphology, Evolution, Ecology, Pathology and Control, Microbial Symbionts

Stable Isotope Paleoecology In The Bridgerian (Early Eocene): Investigation Of The Bridgerian Crash And The Canopy Effect, Aaron M. English

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The Early Eocene Climatic Optimum (EECO) was the warmest sustained interval of the Cenozoic. Its waning stages coincided with a marked decline in mammalian biodiversity known as the Bridgerian Crash, which was likely driven by increasingly cooler and drier conditions. Paleobotanical evidence suggests the early Eocene supported wet, subtropical to tropical forests at mid-latitudes, however the structure of these forests at the close of the EECO remains poorly understood. In this study, I measure carbon isotope values (d¹³C_E) from the enamel of early Bridgerian (~52.2 – 48.3 Ma) herbivorous mammals from the Greater Green River …

A Practice-Based Framework For Teaching Geography At The Secondary Level, Kyle F. Tredinnick

Department of Geography: Dissertations, Theses, and Student Research

Further work is necessary to carry out the goals set forth in geography education initiatives like the Geography for Life: National Geography Standards and Road Map for 21^st Century Geography Education Project. Methods to communicate the focus of geographic lessons at the secondary level can help guide teachers who are otherwise unaware of the ability for geography to answer questions and develop solutions to problems. Research and development of effective instructional tools to teach geography is needed. This research aims to provide a practice-based model for lesson-development in geography, as supported in academic literature. Input from higher-education faculty …

Characterization Of Sediment Loads And Size Distribution In Nebraska Roadway Runoff, Pavel Shrestha

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The Nebraska Department of Transportation (NDOT) must manage sediment and pollutant loads from roadway runoff to meet stormwater regulations for discharges into impaired waters. The SAFL Baffle, a hydrodynamic separator used by NDOT, depends on accurate estimates of total suspended solids (TSS) and particle size distribution (PSD). However, existing studies show large variability in these characteristics, limiting their relevance to Nebraska roadways.

This study monitored stormwater runoff for 1.5 years at four NDOT-maintained sites—two in Lincoln and two in Beatrice—that received runoff from areas outside the roadway right-of-way. The SAFL Baffle was evaluated using the SHSAM (Sizing Hydrodynamic Separators and …

The Big Bang Theory’S Blurred (Tele)Vision Of Scientific Ethics: Some Thoughts For Educators Who Want To Change The Channel, Lee-Anne Broadhead, Sean J. Howard

Dialogue: The Interdisciplinary Journal of Popular Culture and Pedagogy

This article investigates the way the popular American television program The Big Bang Theory represents the pursuit of scientific knowledge and reflects on the cultural and educational implications of the show’s contradictory problematization and valorization of the reductionist method at the core of modern Eurocentric science. Drawing on story-lines relating to military research, animal experimentation, and pharmaceutical drug trials, we consider the show’s precarious balance of implicit critique (the consistent exposé of systematically violent, often unethical research) and overt celebration (the presentation of science as “cool,” and its practitioners as flawed but endearing). This tension, we argue, enhances the show’s …

How Eppley Airfield Could Be Reducing Your Power Bill (But They’Re Not), Cherry Pham

Op-Eds from ENSC230 Energy and the Environment: Economics and Policies

Eppley Airfield in Nebraska is spending $950 million on their renovation and services are still running, even during construction. Part of the airport’s renovation budget could be allotted to installing solar canopies. In the long run, airports with solar canopies reduces their own electricity expenses.