Digital Commons Network^™

Microbial Response To Biodegradable Mulch: Can Degradation Rate Be Accelerated By Management?, M. Benjamin Samuelson

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

Single-use, petroleum-based polyethylene mulch is ubiquitous in certified organic mulched vegetable systems, representing a broken nutrient cycle and a waste concern. Current organic-allowable biodegradable mulches cannot match the performance of polyethylene, in part because of the requirements that they contain 100% bio-based feedstock, and biodegrade within two years after soil incorporation. It is valuable to understand whether management can influence postharvest degradation rate of mulch films. Two biodegradable mulches: a potentially organic nonwoven polylactic acid and wood particle prototype (PLA), and a widely-adopted non-organic starch/copolymer blend, Bio360® (BLK), were used in field trials in two distinct ecoregions of Nebraska, at …

Wyandot, Shawnee, And African American Resistance To Slavery In Ohio And Kansas, Diane Miller

Department of History: Dissertations, Theses, and Student Research

From the colonial period, enslaved Africans escaped bondage. Colonial records and treaties reveal that they often sought refuge with Indian tribes. This resistance to slavery through escape and flight constituted the Underground Railroad. As European colonies developed into the United States, alliances of subaltern groups posed a threat. Colonizers and settlers aimed to divide and control these groups and arrived at the intertwined public policies of African chattel slavery and Indian removal. Tribal abolitionism and participation in the Underground Railroad was more pronounced than scholars have recognized and constituted an important challenge to the expansion of slavery.

Encounters between fugitive …

Is This What You Wanted?: Expectations, Choice, And Rhetorical Agency In Composition, Caitlin C. Leibman

Department of English: Dissertations, Theses, and Student Research

Choices are a given in rhetorical education, but composition has not given enough attention to the relationship between choices and students’ experiences of rhetorical agency. This dissertation uses expectations as an entry point and choices as a unit of analysis to explore how students navigate and understand their decision-making processes during a single composition project. Drawing from activity theory, this study analyzes classroom data including drafts, author’s notes, and peer response materials as well as student interview data and writing center consultation transcripts. This dynamic approach allows for an exploration of the messiness of the process, creating a portrait of …

Drought Impacts Assessment In Brazil: A Remote Sensing Approach, Denis Mariano

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

Climate extremes are becoming more frequent in Brazil; studies project an increase in drought occurrences in many regions of the country. In the south, drought events lead to crop yield losses affecting the value chain and, therefore, the local economy. In the northeast, extended periods of drought lead to potential land degradation, affecting the livelihood and hindering local development. In the southern Amazon, an area that experienced intense land use change (LUC) in the last, the impacts are even more complex, ranging from crop yield loss and forest resilience loss, affecting ecosystem health and putting a threat on the native …

Regime Detection Measures For The Practical Ecologist, Jessica L. Burnett

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

Forecasting undesirable change is, arguably, the holy grail of ecology. Paired with an understanding of system interactions, a forecast is ideal if it provides reliable predictions in sufficient time to prevent or mitigate unwanted systemic change. Early warning systems (or early warning signals, early warning indicators) have been developed and tested for some ecological systems data, but have been mostly applied to marine fisheries time series and nutrient loadings in shallow lakes. Despite the numerous quantitative methods proposed for identifying or forecasting regime shifts in ecological data, few are used in practice. This dissertation contributes to our understanding of the …

Nitrate Removal And Placement Of Floating Treatment Wetlands In The Midwest, Mary G. Keilhauer

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

The Midwestern United States is vulnerable to eutrophic conditions from high nutrient concentrations. Recommendations for nonpoint source pollution management include runoff treatment (i.e., filter strips, riparian buffers) and in-situ lake treatment practices (i.e., aluminum sulfate (alum) treatments, aeration, up/downdraft pumping, floating treatment wetlands). Floating treatment wetlands (FTWs) are an innovative wetland design for nutrient removal from nonpoint sources and provide a unique in-situ treatment. Best management practice studies have commonly focused on adjacent to water practices, which have resulted in a gap for guidance for in-situ treatment placement and design. Therefore, the objectives of this project were to (1) Quantify …

Optimal Design For A Causal Structure, Zaher Kmail

Department of Statistics: Dissertations, Theses, and Student Research

Linear models and mixed models are important statistical tools. But in many natural phenomena, there is more than one endogenous variable involved and these variables are related in a sophisticated way. Structural Equation Modeling (SEM) is often used to model the complex relationships between the endogenous and exogenous variables. It was first implemented in research to estimate the strength and direction of direct and indirect effects among variables and to measure the relative magnitude of each causal factor.

Historically, traditional optimal design theory focuses on univariate linear, nonlinear, and mixed models. There is no current literature on the subject of …

Creating A “Good” Olmstead Plan For People With Serious Mental Illness: An Empirical Evaluation Of The Legal Frameworks, Andrea Avila

Department of Psychology: Dissertations, Theses, and Student Research

Olmstead v. L.C. ex rel Zimring (1999) was a landmark US Supreme Court decision holding that unjustified segregation of people with disabilities is impermissible discrimination; specifically, if the clinician and client believe community integration to be appropriate, the state must have reasonable accommodations in place for the client to be in the community. Enforcement of the Olmstead decision for people with serious mental illness has taken many shapes, from the DOJ’s settlement agreements requiring substantive development of community mental health services and aggressive community integration protocols, to the Third Circuit approach which requires only lower census numbers in the state …

Environmental Sampling Techniques For Herd-Level Surveillance Of Bovine Viral Diarrhea Virus, Jaden Carlson

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Control of Bovine Viral Diarrhea Virus (BVDV) relies on resource-intensive individual animal sampling to detect and remove persistently infected (PI) cattle. Herd-level surveillance tools would be useful for herds with unknown BVDV status and for monitoring herds with BVDV-free status. The overall objective of this thesis is to explore the viability of BVDV surveillance at a herd-level using samples collected without handling individual animals. The first objective was to determine the feasibility of using stable flies as a sampling tool to detect BVDV. The second objective was to determine the feasibility of using drinking water to detect BVDV. To accomplish …

Inhibitory Effects Of Shiitake-Derived Exosome-Like Nanoparticles On Nlrp3 Inflammasome Activation, Yizhu Lu

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

The NLRP3 inflammasome is a critical mediator of inflammation and consists of the sensor NOD-like receptor family, pyrin domain containing 3 (NLRP3), the adaptor apoptotic speck protein containing a caspase recruitment domain (ASC), and the effector caspase-1. Dysregulated or excessive activation of the NLRP3 inflammasome contributes to pathogenesis of diverse inflammatory diseases such as Type 2 diabetes and atherosclerosis. Therefore, the NLRP3 inflammasome is a promising therapeutic target for treating these diseases. Extracellular vesicles (EVs) are membrane-enclosed tiny particles released by almost any type of cells and they are involved in the intercellular communication by transferring their cargos including RNAs, …

Transport And Distribution Of Bovine Milk Exosomes And Mir-34a Cargo In Murine Cerebral Cortex Endothelial Bend.3 Cells And Bv2 Microglia, Pearl Ebea

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

The blood-brain barrier (BBB) poses an obstacle in the delivery of drugs to the brain. Bovine milk exosomes (BME) are explored for delivering antisense oligonucleotides to tumors, because BME are bioavailable and protect RNA cargos against degradation in the gastrointestinal tract. This study had the following objectives: 1) assess the transport kinetics of BME and their RNA cargos and secretion of RNA across the apical membrane in murine cerebral cortex endothelial bEnd.3 cells and 2) determine whether murine brain BV2 microglia have the potential to accumulate and, therefore, eliminate BME that crossed the BBB. The uptake of BME labeled with …

Cooperative Learning For The Consensus Of Multi-Agent Systems, Qishuai Liu

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

Due to a lot of attention for the multi-agent system in recent years, the consensus algorithm gained immense popularity for building fault-tolerant systems in system and control theory. Generally, the consensus algorithm drives the swarm of agents to work as a coherent group that can reach an agreement regarding a certain quantity of interest, which depends on the state of all agents themselves. The most common consensus algorithm is the average consensus, the final consensus value of which is equal to the average of the initial values. If we want the agents to find the best area of the particular …

Analysis Of Social Unrest Events Using Spatio-Temporal Data Clustering And Agent-Based Modelling, Sudeep Basnet

School of Computing: Dissertations, Theses, and Student Research

Social unrest such as appeals, protests, conflicts, fights and mass violence can result from a wide ranging of diverse factors making the analysis of causal relationships challenging, with high complexity and uncertainty. Unrest events can result in significant changes in a society ranging from new policies and regulations to regime change. Widespread unrest often arises through a process of feedback and cascading of a collection of past events over time, in regions that are close to each other. Understanding the dynamics of these social events and extrapolating their future growth will enable analysts to detect or forecast major societal events. …

Investigating Parental Effects On End-Use Quality In Hard Winter Wheat (Triticum Aestivum L.) Hybrids, Anthony Delaney

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

To optimize the performance and marketing of hybrid wheat, breeders need to understand the impact parents have on end-use quality. The goal of this study was to investigate the inheritance of end-use quality traits of hard winter wheat reciprocal hybrids produced by Easterly (2017). The 2016 analysis included 71 reciprocal hybrid combinations from 13 parents and the 2017 analysis included 79 reciprocal hybrid combinations from 14 parents. The reciprocals were composed of crosses between the top performing and bottom performing parents with respect to end-use quality as quantified by a Mixograph, a SDS sedimentation assay, and a SDS-SRC hybrid assay. …

Rust And Viral Mosaic Diseases In Biofuel Switchgrass, Anthony A. Muhle

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

Switchgrass (Panicum virgatum L.) is a perennial warm-season monocot that is indigenous to locations in North America east of the Rocky Mountains, and is considered a model grass for biofuel feedstock production. As switchgrass production increases, diseases pose a potential threat to biomass production and ethanol extraction. The two predominant switchgrass diseases in Nebraska are rust caused by Puccinia spp. and a viral mosaic disease caused by Panicum mosaic virus (PMV) and its associated Satellite panicum mosaic virus (SPMV). In this thesis, one study determined how SPMV affects PMV infection and systemic spread in two populations of switchgrass at different …

Hormonal Signaling Induced In Soybean By Lysobacter Enzymogenes Strain C3, Jessica C. Walnut

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

The biological control bacterium Lysobacter enzymogenes strain C3 has been shown to suppress fungal diseases by producing a suite of lytic enzymes and antimicrobial secondary metabolites. Previous studies have found that C3, when applied to grass and cereal plants, also is capable of inducing local and systemic resistance against fungal pathogens. It is unknown, however, whether the bacterium has the ability to induce resistance in dicots and what signaling pathways are involved. This study assessed the ability of C3 to trigger local and systemic induced resistance responses in soybean (Glycine max ‘Williams82’) by analyzing relative expression of salicylic acid …

Dual Biological Control: Characterization Of Fungi And Bacteria To Control Granary Weevil And Fungal Pathogens Of Stored Grain, Gülçin Ercan

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

Cereals are main food sources for humans and animals. However, during storage, cereal grains can be infested by insects and fungi. One of the most important insect storage pests is Sitophilus granarius (L., Coleoptera: Curculionidae). Adults and larvae can cause serious grain losses. In addition to insect pests, fungal pathogens may also invade the grain and cause economic loss, including contamination with mycotoxins, which threaten mammal health by causing serious disease. The most common mycotoxigenic grain fungi are species that belong to the genera Fusarium, Aspergillus and Penicillium. Currently, the most commonly used management strategies for insect and …

The Value Of Inspection Stations For Detecting Nonindigenous Species Lacking Agricultural Significance: The Mexican Treefrog, Smilisca Baudinii Complex (Duméril And Bibron 1841) (Hylidae), Interdicted In Florida, Usa, From A Shipment Of Peppers, Louis A. Somma

Papers in Herpetology

A Mexican Treefrog, Smilisca baudinii, a nonindigenous species, was interdicted for the first time from an imported shipment of peppers. The value of agriculture inspection stations used to make these interdictions is discussed. This is a single cargo interception (Stage 1: Colautti and MacIsaac 2004) and the first record for S. baudinii intercepted in Florida. Currently no evidence suggests that S. baudinii has been successfully introduced into and established in Florida, although this species could survive climatic conditions in the southern part of the state and at the scheduled destination of this shipment.

Cargo transport of alien species is a …

Effects Of Late Gestation Supplementation And Creep Feeding On Spring Calving Beef Cows In The Nebraska Sandhills, Devin Lynn Broadhead

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

The objectives of this research were to 1) evaluate the effects of late gestation supplementation, synchronization and creep feeding on cow and calf production traits 2) evaluate the pooled effects of 5 studies involving late gestation supplementation on cow and calf traits. Experiment 1 was a three year study conducted on 8 pastures at the Gudmundsen Sandhills Laboratory. Cows were assigned to 1 of 4 late-gestation supplementation treatments, postpartum progestin or control, and 1 of 2 creep feed treatments to make up a 4 x 2 x 2 factorial arrangement. Calves were followed through to slaughter.

Experiment 2 involved 5 …

Effects Of Alternative Carbohydrate Sources And Soybean-Derived Isoflavones On The Microbiome And Immune System Of Nursery Piglets And Intestinal Porcine Epithelial Cell Line J-2, Sydney Kinstler

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

Four experiments were conducted to characterize the microbiome of the piglet and observe effects of diet on growth performance and immunity. In Exp. 1, 96 nursery piglets were fed varying carbohydrate sources and in Exp. 2, 64 piglets were fed a soy protein concentrate or soybean meal as-is or supplemented with an isoflavone concentrate. Body and feeder weights were measured for growth performance estimation. Luminal contents and scrapings were isolated for microbial composition analysis. Fecal and blood samples were extracted in Exp. 2 for microbiome and immunity analysis. Diets did not affect growth performance (P > 0.10); however, Exp. 1 …

Phosphonate-Directed Catalytic Asymmetric Hydroboration: Synthesis Of Functionalized Chiral Secondary And Tertiary Boronic Esters And Mechanistic Insights, Suman Chakrabarty

Department of Chemistry: Dissertations, Theses, and Student Research

Over the past 30 years, catalytic asymmetric hydroboration (CAHB) of alkenes has emerged as a leading methodology to access chiral primary and secondary boronic esters. However, it wasn’t until 2015 that directed-CAHB was for the first time shown to efficiently access chiral tertiary boronic esters. The latter are excellent precursors to synthetically challenging structural motifs such as chiral tertiary alcohols, carbinamines and all-carbon quaternary stereocenters via stereospecific C-B bond substitutions. This dissertation focuses on phosphonate-directed CAHB of diverse alkene substrates, including challenging stereodefined trisubstituted alkenes, to efficiently access multifunctional chiral secondary and tertiary boronic esters. Mechanistic insights obtained via deuterium …

Validation Of A Death Assay For Angiostrongylus Cantonensis Larvae (L3) Using Propidium Iodide In A Rat Model (Rattus Norvegicus), Susan I. Jarvi, John Jacob, Robert T. Sugihara, Israel L. Leinbach, Ina H. Klasner, Lisa M. Kaluna, Kirsten A. Snook, M. Kathleen Howe, Steven H. Jacquier, Ingo Lange, Abigail L. Atkinson, Ashley R. Deane, Chris N. Niebuhr, Shane R. Siers

United States Department of Agriculture Wildlife Services: Staff Publications

Angiostrongylus cantonensis is a pathogenic nematode and the cause of neuroangiostrongyliasis, an eosinophilic meningitis more commonly known as rat lungworm disease. Transmission is thought to be primarily due to ingestion of infective third stage larvae (L3) in gastropods, on produce, or in contaminated water. The gold standard to determine the effects of physical and chemical treatments on the infectivity of A. cantonensis L3 larvae is to infect rodents with treated L3 larvae and monitor for infection, but animal studies are laborious and expensive and also raise ethical concerns. This study demonstrates propidium iodide (PI) to be a reliable marker of …

High Pressure Thawing Of Raw Poultry Meats, Ali Alqaraghuli

Department of Food Science and Technology: Dissertations, Theses, and Student Research

The melting temperature of water reaches its minimum when pressurized from 0 °C at atmospheric pressure down to -22 °C at 220 MPa, showing that frozen products at atmospheric pressure (0.1 MPa) can be thawed rapidly by simply increasing the pressure to 210-250 MPa. High pressure thawing (HPT) of poultry meats (ground chicken, chicken breast, thigh, liver, gizzard, and heart) commonly used in the raw pet food industry was evaluated at 240 MPa, two processing fluid temperatures (refrigerated, 0-10 °C and room, 20-30 °C), and four holding times (1, 180, 360, and 540 s). Changes in color via * * …

Changes In Mammalian Abundance Through The Eocene–Oligocene Climate Transition In The White River Group Of Nebraska, Usa, Robert Gillham

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

Marine records show major cooling during the Eocene-Oligocene Climate Transition (EOCT). Most proxy studies in the White River Group suggest drying across the EOCT, and some suggest cooling. The lower resolution continental record has hindered a direct correlation of the marine climate record to Nebraska. I explore various correlation schemes and what they imply for faunal changes. This study compiles and analyzes data from 4,875 specimens in the University of Nebraska State Museum (UNSM) collection to test the hypothesis that climate change across the Eocene-Oligocene (E-O) boundary caused significant abundance changes in mammals. A series of binning schemes was created. …

Human-Cognition-In-The-Loop: A Framework To Include Decision Process In Closed Loop Control, Mehdi Firouznia

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

This thesis proposes a framework to include human cognitive process in making decision into control loop. Our approach in solving this problem is to add a complementary control which includes a model of human decision to the controller, capable of predicting human command accuracy in the near future. The outcome of decision unit can either be presented to the operator as a directive or may adjust the issued command toward better results. In order to construct human decision model, we combined tree approaches of bio-physical connectionist, mathematical abstraction and behavioral cognitive models in the adaptive gain theory framework. We first …

Type X Strains Of Toxoplasma Gondii Are Virulent For Southern Sea Otters (Enhydra Lutris Nereis) And Present In Felids From Nearby Watersheds, Karen Shapiro, Elizabeth Vanwormer, Andrea Packham, Erin Dodd, Patricia A. Conrad, Melissa Miller

School of Veterinary and Biomedical Sciences: Faculty Publications

Why some Toxoplasma gondii-infected southern sea otters (Enhydra lutris nereis) develop fatal toxoplasmosis while others have incidental or mild chronic infections has long puzzled the scientific community. We assessed robust datasets on T. gondii molecular characterization in relation to detailed necropsy and histopathology results to evaluate whether parasite genotype influences pathological outcomes in sea otters that stranded along the central California coast. Genotypes isolated from sea otters were also compared with T. gondii strains circulating in felids from nearby coastal regions to assess land-to-sea parasite transmission. The predominant T. gondii genotypes isolated from 135 necropsied sea otters were atypical Type …

Reproductive Ecology And Movement Of Pallid Sturgeon In The Upper Missouri River, Montana, Luke M. Holmquist, Christopher S. Guy, Anne Tews, David J. Trimpe, Molly A.H. Webb

United States Fish and Wildlife Service: Publications

Successful recruitment of endangered pallid sturgeon has not been documented in the upper Missouri River basin for decades, and research on the reproductive ecology of pallid sturgeon has been hindered by low sample size. A conservation propagation program was initiated in the 1990s, and the oldest age class of hatchery‐origin pallid sturgeon are becoming sexually mature increasing the number of reproductively‐ active fish in the system. However, it is currently unknown how the reproductive ecology of hatchery‐origin pallid sturgeon relates to the few remaining wild fish. Following spring reproductive assessments, weekly relocations were recorded for each individual from late‐May to …

Assessing Anthocyanin Biosynthesis In Solanaceae As A Model Pathway For Secondary Metabolism, Zou Li, Trisha Vickrey, Moira G. Mcnally, Shirley J. Sato, Thomas E. Clemente, Jeffrey P. Mower

Center for Plant Science Innovation: Faculty Publications

Solanaceae have played an important role in elucidating how flower color is specified by the flavonoid biosynthesis pathway (FBP), which produces anthocyanins and other secondary metabolites. With well-established reverse genetics tools and rich genomic resources, Solanaceae provide a robust framework to examine the diversification of this well-studied pathway over short evolutionary timescales and to evaluate the predictability of genetic perturbation on pathway flux. Genomes of eight Solanaceae species, nine related asterids, and four rosids were mined to evaluate variation in copy number of the suite of FBP enzymes involved in anthocyanin biosynthesis. Comparison of annotation sources indicated that the NCBI …

The Design And Implementation Of Aida: Ancient Inscription Database And Analytics System, M. Parvez Rashid

School of Computing: Dissertations, Theses, and Student Research

AIDA, the Ancient Inscription Database and Analytic system can be used to translate and analyze ancient Minoan language. The AIDA system currently stores three types of ancient Minoan inscriptions: Linear A, Cretan Hieroglyph and Phaistos Disk inscriptions. In addition, AIDA provides candidate syllabic values and translations of Minoan words and inscriptions into English. The AIDA system allows the users to change these candidate phonetic assignments to the Linear A, Cretan Hieroglyph and Phaistos symbols. Hence the AIDA system provides for various scholars not only a convenient online resource to browse Minoan inscriptions but also provides an analysis tool to explore …

Mid To Late Season Weed Detection In Soybean Production Fields Using Unmanned Aerial Vehicle And Machine Learning, Arun Narenthiran Veeranampalayam Sivakumar

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

Mid-late season weeds are those that escape the early season herbicide applications and those that emerge late in the season. They might not affect the crop yield, but if uncontrolled, will produce a large number of seeds causing problems in the subsequent years. In this study, high-resolution aerial imagery of mid-season weeds in soybean fields was captured using an unmanned aerial vehicle (UAV) and the performance of two different automated weed detection approaches – patch-based classification and object detection was studied for site-specific weed management. For the patch-based classification approach, several conventional machine learning models on Haralick texture features were …