Digital Commons Network^™

Assessing Even Flat-Fan Nozzles For Spot Spray Herbicide Applications, Thiago H. Vitti

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Herbicide efficiency in row-crop agriculture can be improved using precision technologies for controlling weeds and minimize agronomic, economic, and environmental impacts. Site-specific weed management technologies, such as spot-sprayers, allow herbicides to be sprayed only where weeds are present in the field. Understanding application parameters and their influence on weed control for site-specific spot-spray applications is essential. This research involved laboratory and greenhouse studies to investigate the coverage and coefficient of variation (CV) of even flat-fan spray nozzles under different spot-spray application scenarios, as well as the effect of weed size and application method on the control of various weed species …

Identifying Genes Linked To Variation In Metabolic And Whole Plant Phenotypes Using Data From Genome Resequencing, Transcriptomics, And Metabolic Profiling Of A Field-Grown Maize Diversity Panel, Ramesh Kanna Mathivanan

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Maize metabolism is highly complex and influenced by genetic variation, yet the specific genes contributing to this variation and their links to non-metabolic traits remain less understood. To address this knowledge gap, we identified genes involved in maize metabolic variation and linked them to non-metabolic traits. We utilized a quadruplicate dataset of whole genome resequencing, transcriptomic, metabolic, and whole plant phenotype data from a single common field experiment of 660 diverse maize inbred lines. Leaf samples were collected shortly before flowering and analyzed using GC-MS for 26 metabolites. A Resampling Model Inclusion Probability Genome-Wide Association Study (RMIPGWAS) of approximately 2.6 …

Exploring Intraplate Seismicity In The Midwest, Alexa Fernández

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

Intraplate seismicity represents a notable occurrence within the stable North American Craton. This research explores the potential sources of stresses that could reactivate older faults and influence seismic activity within this region. Among these sources, the enduring impact of the last glacial period is considered, which includes continued glacial isostatic adjustments (GIA). During GIA the lithosphere rebounds due to the retreating ice, and the forebulge caused by far-field flexure in response to the glacial load, collapses. This results in significant faulting, fracturing, and seismic activity associated with the deglaciation phase. The adjustment of the lithosphere manifests as both near surface …

My Last Concussion, Shannon Valkr

Department of English: Dissertations, Theses, and Student Research

MY LAST CONCUSSION is a thesis consisting of a critical introduction, a number of poetic influences, and a collection of poems. The introduction touches on the themes of the collection, my personal history with my subject, my changing approach to poetry, and a brief evaluation of the work as a whole. It details my approach to Catholicism, paganism, transgender identity, and oppression. My work grapples with both my current understanding of myself and my inability to enunciate my reality in the past. I aim to view divinity and personal history through a lens of queerness.

Advisor: Kwame Dawes

Virion Composition Of Wheat Streak Mosaic Virus (Wsmv) And Its Use As An Expression Vector, Sourav Pal

Department of Plant Pathology: Dissertations, Theses, and Student Research

Wheat (Triticum aestivum L.) is the principal cereal grown in the United States, whose production ranks third in the world. Bacterial leaf streak (BLS) disease caused by Xanthomonas translucens pv. undulosa (xtu) is an emerging threat to wheat production in the Great Plains region of the United States of America. In this study, we engineered sequences encoding several plant-based antimicrobial peptides (AMP) were engineered into the WSMV genome and examined their effect on BLS disease in wheat infected by WSMV harboring AMP sequences. Out of nine AMPs, wheat expressing Ace-AMP1, PDF13, TK-AMP-D1, and TK-AMP-D3 produced resistance against the …

Transforming Grassland Conservation: Challenges And Opportunities Across Law, Policy, And Human Dimensions, Conor D. Barnes

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

Great Plains social-ecological systems are facing growing pressure from complex, ‘wicked’ problems. Addressing these problems will require integrating ecological resilience and complex systems thinking concepts into our legal framework in order to better reflect the changing ecological reality of the Great Plains and promote flexibility and adaptability in the face of that change. In this dissertation, I examine how past and present policy priorities have affected social-ecological systems on the Great Plains, and how ecological resilience and complex systems thinking might be applied to grassland management policy. In Chapter 2, I examine the rapid progress made in the adoption of …

Further Developing Drought Early Warning Information Systems Using Mixed-Methods And Multiple Streams Of Data, Caily Claire Schwartz

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

Drought is a complex phenomenon with varying degrees of impacts and monitoring methods. No drought is alike, creating a challenge for both water managers and communities. No area is immune to a drought. Due to the cyclical nature of drought events, clear information to those impacted is necessary to reduce risk and move towards proactive responses, as opposed to reactive responses. To better provide communication and mitigation tools, Drought Early Warning Information Systems (DEWIS) have been developed in various regions and contexts. To improve early warning, an understanding of the end user’s perceptions of risk, and the applicability of data …

Development Of Feature Extraction Models To Improve Image Analysis Applications In Cancer, Yu Shi

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

Cancer poses a significant global health challenge. With an estimated 20 million new cases diagnosed worldwide in 2022 and 9.7 million fatalities attributable to the disease, the economic burden of cancer is immense. It impacts healthcare systems and imposes substantial costs for its care on patients and their families. Despite advancements in early detection, prevention, and treatment that have reduced overall cancer mortality rates, the growing prevalence of cancer, particularly among younger individuals, remains a pressing issue.

Recent advancements in medical imaging technology have progressed significantly with the help of emerging computer vision and artificial intelligence (AI) technology. Despite these …

A Study On The Vanishing Of Ext, Andrew J. Soto Levins

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

This thesis has two goals. The first is to study an Ext analog of the rigidity of Tor, and the second is to study Auslander bounds.

In Chapter 2 we show that if R is an unramified hypersurface, if M and N are finitely generated R-modules, and if the nth Ext modules of M against N is zero for some n less than or equal to the grade of M, then the ith Ext module of M against N is zero for all i less than or equal to n. A corollary of this says that if …

Semigroup Well-Posedness And Finite Element Analysis Of A Biot-Stokes Interactive System, Sara Mcknight

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

The coupling of a porous medium modeled by the Biot equations and a fluid has many biological applications. There are numerous ways by which to model the fluid and to couple the porous medium with the fluid. This particular model couples the Biot equations to Stokes flow along the boundary, through the Beavers-Joseph-Saffman conditions. We address semigroup well-posedness of the system via an inf-sup approach, which along the way requires consideration of a related but uncoupled static Biot system. We also present the results of finite element analysis on both the uncoupled Biot system and the coupled system.

Advisor: Sara …

Investigation Of Faults In Air-Conditioning Systems In Commercial Buildings: Occurrence, Diagnostic Validation, And Energy Impacts, Yuxuan Chen

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

In commercial buildings, fault detection and diagnosis (FDD) tools have been developed for detecting and diagnosing faults in building systems, which can provide useful information regarding fault locations and potential causes of faults, so that building operators and facility staff can be notified in time and quickly respond as problems arise. Nowadays, there are many commercial FDD tools available in the market, and these tools have been widely adopted in large- and medium-scale commercial buildings in the United States. Several studies have demonstrated the energy saving potential with the use of FDD in commercial HVAC systems, and one critical aspect …

Integrating Water And Nitrogen Management For Sustainable Agriculture: Optimizing Resource Use Efficiency And Maximizing Crop Productivity, Jiaming Duan

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

Advisors: Derek Heeren and Daran Rudnick Maize, accounting for over 95% of national grain production in the United States, is highly sensitive to water and nitrogen (N) inputs. Conventional agricultural practices often lead to excessive application, causing groundwater contamination through nitrate leaching. Therefore, there is a demand for integrating water and nitrogen management with innovative scheduling methods for sustainable agricultural development.

This dissertation first reviewed two decades of U.S.-based research, highlighting the optimal management of water and N to enhance yield, water use efficiency (WUE), and nitrogen use efficiency (NUE). Findings indicate that maintaining optimal levels of N and water …

"I Will Write Mad Stories": The Hysterical "I" In The Diaries Of George Eliot, Charlotte Forten Grimke, Virginia Woolf, And Sylvia Plath, Jaclyn Marie Swiderski

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

This dissertation focuses on the long history of hysteria and the ways in which it has been used to denigrate and silence disabled women. Women diagnosed as hysterical, by either the medical establishment or the court of public opinion, are denied the right to generate knowledge about and for themselves – they are epistemologically disabled. The author argues that hysterical women have unique ways of looking at and understanding the world which push back against their epistemological disablement. In order to uncover some of this history of hysterical women, this dissertation uses the diaries of four “hysterical” women over the …

A Data-Driven Discovery System For Studying Extracellular Microrna Sorting And Rna-Protein Interactions, Sasan Azizian

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

Interactions between microRNAs (miRNAs) and RNA-binding proteins (RBPs) are pivotal in miRNA-mediated sorting, yet the molecular mechanisms underlying these interactions remain largely understudied. Few miRNA-binding proteins have been verified, typically requiring extensive laboratory work. This study introduces DeepMiRBP, a novel hybrid deep learning model designed to predict microRNA-binding proteins. The model integrates Bidirectional Long Short-Term Memory (Bi-LSTM) networks with attention mechanisms, transfer learning, and cosine similarity to offer a robust computational approach for inferring miRNA-protein interactions.

DeepMiRBP is implemented through two distinct architectures. The first architecture employs a Y-shaped model that uses Bi-LSTM networks and transfer learning to extract contextual …

Long Term Ultrasonic Monitoring And Machine Learning Investigation Of Micro-Crack Damaged Concrete, Yalei Tang

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

The thermal modulation method is a recently developed nonlinear ultrasonic technique for evaluating material damage. This method utilizes thermal strain changes resulting from temperature variations to excite the nonlinear behavior of materials and modulate high-frequency ultrasonic waves within them. Its working principle suggests significant potential for application in large-scale concrete structures and in-situ monitoring of real structures. Despite numerous laboratory demonstrations of its effectiveness, several gaps remain before it can be applied to in-service large concrete structures.

This study investigates the potential of the thermal modulation technique for evaluating concrete structures in ambient conditions, addressing key uncertainties for practical implementation. …

Role Of The Malate Dehydrogenase-Citrate Synthase Metabolon In Metabolic Flux Regulation, Joy John Omini

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

The TCA cycle enzymes- malate dehydrogenase (MDH) and citrate synthase (CS)- interact to transfer oxaloacetate from the active site of MDH to the active site of CS, through an electropositive channel. The MDH-CS metabolon is highly conserved across different domains of life, and it has been associated with many advantages. Some of these advantages include protecting oxaloacetate from competing enzymes like aspartate aminotransferase, allowing the thermodynamically unfavorable MDH forward reaction to occur and increasing the local concentration of oxaloacetate within the active site of CS. These advantages and conservativeness of the MDH-CS metabolon indicate that it is highly important to …

Teacher-Child Interaction Quality In Free Choice And Associations With Child Peer-Related Social Competence, Yuenjung Joo

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

Children’s peer-related social skills in early childhood set the stage for school readiness, social competence, and lifelong well-being. Preschoolers spend most of their classroom time in free choice, offering substantial opportunities for learning experiences that facilitate peer interactions that support social development. Yet, little is known about how early childhood teachers can best optimize children’s social learning without disrupting the benefits of play during this time. The purpose of this study is to investigate how preschool teachers’ social support behaviors during free choice align with children’s social needs (i.e., fit of teacher-child social interaction) and the association between the fit …

Spreads And Transversals And Their Connection To Geproci Sets, Allison Joan Ganger

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

Spreads of [set of prime numbers]³ over finite fields can yield geproci sets. We study the existence of transversals to such spreads, proving that spreads with two transversals exist for all finite fields, before further considering the groupoids coming from spreads when transversals do or do not exist. This is further considered for spreads of higher dimensional projective spaces. We also consider how certain spreads might generalize to characteristic zero and the connection to the previously known geproci sets coming from the root systems D₄ and F₄.

Advisor: Brian Harbourne

Perturbations Of Representations Of Cartan Inclusions, Catherine Zimmitti

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

A free semigroup algebra is the unital, weak operator topology closed algebra generated by a collection of Cuntz-Toeplitz isometries in B(H). Ken Davidson and David Pitts asked in [9] if a self-adjoint free semigroup algebra exists; Charles Read answered this question in [28] by constructing such an example, which Ken Davidson later simplified in [8]. The construction takes a standard representation of O₂ and multiplies it by a unitary operator in the diagonal MASA of the representation. This results in a new "perturbed" representation of O₂ generating a self-adjoint free semigroup algebra.

In this thesis, …

Laser Surface Processing For Enhanced Adhesion Between Diamond Coatings And Metallic Substrates, Zhipeng Wu

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

Application of diamond coatings on metallic substrates endows them with superior properties including mechanical robustness and corrosion resistance, rendering them highly adaptable for diverse industrial and technological applications. However, significant disparities in coefficients of thermal expansion (CTEs) result in pronounced residual stress near interfaces, causing delamination of the diamond coatings. Moreover, weak chemical bonding poses a concern for certain metallic substrates. Laser surface processing techniques show promise in enhancing adhesion by altering stress distribution and improving mechanical bonding. Therefore, the research efforts described in this dissertation mainly focus on femtosecond (fs) laser texturing for enhanced adhesion of diamond coatings on …

Three Essentials Of Private Property In Kant, Lauren Michelle Kashi

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

There are three principles of public right describing a civil condition and a citizenry that Kant offers: freedom, equality, and independence. I argue that these three principles offer further justification for both protection of property rights and enforcement of redistributive taxation than Kant’s Universal Law of Right and principles of property acquisition alone can. In a civil condition with legitimized laws protecting private property, citizens enjoy maximal freedom from interference, dependence, and inequality. Indeed, the purpose of the civil condition for Kant is to create such freedoms, which are made manifest by laws enforcing private ownership as well as redistribution …

The Effects Of Anchor Scheme On The Central And Peripheral Contributions To Performance Fatigability, Perceived Responses And Sensations, And Psychological Factors Following Sustained, Isometric Forearm Flexion Tasks To Failure, Robert Walker Smith

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

The Effects of Anchor Scheme on the Central and Peripheral Contributions to Performance Fatigability, Perceived Responses and Sensations, and Psychological Factors Following Sustained, Isometric Forearm Flexion Tasks to Failure Robert W. Smith, Ph.D. University of Nebraska, 2024 Advisor: Terry J. Housh This study assessed time to task failure (TTF), performance fatigability (PF), neuromuscular responses, central and peripheral measures of fatigue, and perceived responses including sensations and psychological factors that contributed to task termination during sustained, isometric forearm flexion tasks anchored to ratings of perceived exertion (RPE) and the torque corresponding to RPE. Fifteen men (age = 21.5 ± 2.3 yrs; …

Applying Circuit Theory To Describe Changes In Structural Landscape Connectivity In Response To Wildfire, Christian Ross Nielsen

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

Understanding and conserving ecological connectivity is critical to the preservation of vulnerable landscapes. Circuit theory, in which landscapes are imagined as circuit boards with varying resistances to the flow of current, is being increasingly used to model spatially explicit connectivity of landscapes and to inform land management and conservation decision-making. Utilizing continuous, quantitative estimates of percent cover by five land cover functional groups to create a conductance surface, this study expanded upon an established application of circuit theory that used the open-source software Circuitscape to model species-agnostic, omnidirectional connectivity. This model was automated using Python to create time-series connectivity maps …

Occurrence, Inputs, And Ecological Significance Of Antibiotics And Pharmaceuticals In Western Nebraska Streams, Katelyn F. Glause

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

Few emerging environmental contaminants are as concerning as antibiotics. Human and animal health benefits greatly from the prudent use of antibiotics, yet we give little thought to environmental release of these biologically active compounds. Environmental occurrence of these and other pharmaceutical compounds must be measured in different environmental compartments such as municipal wastewater and in the vicinity of large animal feeding operations to understand potential effects. This study reports the results of a monitoring study in western Nebraska, with a large population of livestock and smaller but more concentrated population of humans, comparing the relative environmental concentrations and loading from …

Analysis Of Drought-Flood Abrupt Alternation Events And Their Impacts In Kenya, Betty Makena

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

Drought-Flood Abrupt Alternation (DFAA) is a compound disaster event that refers to the abrupt shift of extreme drought events to extreme floods resulting in exacerbated impacts on already vulnerable communities and hindering their coping abilities. This study aimed to analyze drought-flood abrupt alternation events and their impacts in Kenya. The first chapter aimed to understand historical drought events in the Greater Horn of Africa and their impacts, while drawing comparisons with the recent 2020-2022 drought period, referred to as the ‘triple dip La Niña’. Datasets used in this study include the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS), Normalized …

Remotely Sensed Early Warning Of Algal Blooms In An Eastern Nebraska Reservoir: A Comparison Of Temporal And Spatial Indicators, Mercy Kipenda

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

Cyanobacterial harmful algal blooms (CyanoHABs) detrimentally affect human, animal, and ecosystem health. Remotely sensed early warning systems for cyanoHABs in inland lakes could contribute to more proactive water quality monitoring and help mitigate negative impacts. Advances in freely available remote sensing imagery, with finer spatial, temporal, and spectral resolutions, present new opportunities for the development and comparative analysis of methods to detect sudden deterioration in lake water quality. In this thesis, I compared and tested for temporal and spatial early warning signals of cyanoHABs in field-based and remotely sensed datasets from 2019 to 2023 in Pawnee Lake in southeast Nebraska, …

Impacts Of Invasive Carp And Their Population Dynamics On Fish Communities In The Missouri River, Joshua F. Kocik

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

Invasive Carp species: Silver Carp Hypophthalmichthys molitrix, Bighead Carp Hypophthalmichthys nobilis, Grass Carp Ctenopharyngodon idella, and Black Carp Mylopharyngodon piceus have both potential and realized abilities to negatively impact native species. Specifically, Bighead Carp and Silver Carp as filter feeders have been theorized to be detrimental not only to adult filter-feeding species, but to many fish which rely on plankton and algae in their early-life stages. The impact of Invasive Carp on the overall fish community remains underexplored. The fish communities below Gavins Point Dam (Invasive Carp present) and Fort Randall Dam (Invasive Carp absent) afford the …

Spatiotemporal Plasticity In Reproductive Readiness And Recruitment Of Ichthyoplankton Of Invasive Silver Carp Along A Western Invasion Front, Jessi L. Urichich

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

Individuals of invasive species at the edge of their invasion distribution may exhibit enhanced reproductive capacity and phenotypic plasticity leading to accelerated range expansion. Environmental conditions in highly fluctuating environments at distribution edges may either promote or hinder such reproductive readiness and phenotypic plasticity. Dynamic habitat conditions and periodic disturbances experienced in prairie streams, such as drought (e.g., low-flow, high water temperatures), may potentially reduce suitable spawning environments and ichthyoplankton recruitment of invasive Silver Carp, potentially slowing range expansion or enabling management strategies that reduce abundance in the absence of a reproducing population. Female Silver Carp batch fecundity, Gonadosomatic Index …

Assessing, Restoring, And Centering Social–Ecological Relationships For Advancing Social–Ecological Resilience In The Northern Great Plains Grasslands, Katia Pilar Carranza Bernal

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

The Northern Great Plains grasslands are social-ecological systems that were shaped by evolutionary and Indigenous social-ecological relationships. European colonization disrupted many of these interactions, including the coupling of fire and grazing, and degraded social-ecological resilience, shifting these grasslands to a new state. For those reasons, my research focused on assessing, restoring, and centering evolutionary and Indigenous social-ecological relationships for advancing social-ecological resilience in the Northern Great Plains grasslands. I first performed a study in the Nebraska Sandhillls assessing the potential of patch-burn grazing to support grassland resilience by comparing its effects to those of rotational grazing. Through vegetation and bird …

Sensitivity Of Present And Future Seasonal Precipitation Over Central United States To The Representation Of Rocky Mountain Topography, Ranasinghe Disanayakalage Sherly Shelton Ranathunga

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

Precipitation change across the Central United States (USA) is of great interest to the research community. Studies using global climate simulations suggest that the “100^th-Meridian”, which separates the “dry west” from the “moist east” will shift to the east as the climate responds to future emissions pathways. However, these simulations are run at relatively coarse resolutions, which do not accurately represent topography. Here, we perform regional simulations using the Weather Research and Forecasting (WRF) model to explore the sensitivity of present and future precipitation patterns across the central USA to the representation of the Rocky Mountains (RM). We …