Digital Commons Network^™

Sustainable Fertilizer Management Practices For Container Nursery Production, Saroj Burlakoti

All Graduate Theses and Dissertations, Fall 2023 to Present

Growing nursery plants in containers requires a timely supply of mineral nutrients for optimum growth. However, there is a misconception among growers that the application of higher doses of fertilizers hastens plant growth; instead, it can lead to runoff and leaching loss of nutrients. Reducing fertilizer application while sustaining healthy plants can not only negate environmental consequences but also save fertilizer costs. For example, two ground covers, Lysimachia nummularia (creeping jenny, moneywort) and Vinca minor 'Bowles' (periwinkle), can be grown for three months by applying 6 mg/L of phosphorus (P) as reduction of P to single application of 6 mg/L …

Role Of Proneurotrophin-P75ntr Signaling In A Mouse Model Of Depression, Kirsten Hodgson

All Graduate Theses and Dissertations, Fall 2023 to Present

Major depressive disorder, or depression, is among the leading causes of disability globally. Despite being a large public health challenge, depression remains difficult to treat as the underlying biology is still unknown and the currently available treatments are limited in effectiveness. This experiment was to test the efficacy of the drug LM11A-31, which works on the signaling pathway of proneurotrophin-p75NTR, a pathway that is not targeted by any currently used antidepressants. Male mice underwent a repeated forced swim, with all the mice receiving saline the first two days and then half the mice receiving saline and half receiving LM11A-31 before …

Causes And Consequences Of Space-Use Behavior Under Predation Risk In A Free-Living System, Brian J. Smith

All Graduate Theses and Dissertations, Fall 2023 to Present

Predators can have important ecological effects through killing and eating their prey, the so-called consumptive effect, but predators can also have a nonconsumptive effect (NCE) on their prey – this happens when the risk of predation itself causes prey to alter their behaviors or other traits and these alterations ultimately reduce prey survival, reproduction, or population size. While scientists understand the consumptive effects of predators well, we are still unsure whether NCEs are important in free-living systems. In this dissertation, I sought to better understand the potential NCEs of predators (wolves and cougars) on elk in northern Yellowstone National Park …

Environmental Factors Associated With Triploid Aspen Occurrence In Intermountain West Landscapes, James A. Walton

All Graduate Theses and Dissertations, Fall 2023 to Present

Polyploidy is common among plants and can contribute to physiological and morphological differences, altering how plants respond to environmental changes, promoting genetic diversification and even species radiation. Quaking aspen (Populus tremuloides), a keystone species associated with high plant and animal diversity is frequently found in mixed diploid/triploid populations in the Intermountain West. Triploid aspen carries an extra chromosomal copy, whereas the diploid type contains two chromosomal copies. High mortality rates and widespread population declines in aspen are of increasing concern in the Intermountain West, and often ascribed to changing climates and drought stress events. The goal of this …

Protein Residue Analysis In Archaeology: A Geological Contamination Experiment, Theresa Popp

All Graduate Theses and Dissertations, Fall 2023 to Present

Protein residue analysis has been used by archaeologists for decades to explore ancient diets and hunting behaviors based on proteins deposited on tools and artifacts, however, protein contamination of buried artifacts has been assumed but lacked formal study. Through a contamination experiment testing different geological contexts (e.g. water movement and freeze-thaw), possible routes of protein contamination within soil were identified, adversely impacting protein residue analysis conducted on buried artifacts. Protein was found to move through soil in large enough concentrations to elicit positive protein residue results on sterile artifacts that never made direct contact with the protein source used in …

Survival And Cause-Specific Mortality Of Mule Deer In The Eastern Sierra Nevada, California, Usa, Glenden Taylor

All Graduate Theses and Dissertations, Fall 2023 to Present

Survival of adult females is a key driver of population dynamics for ungulate species such as mule deer. Accurate survival estimates are therefore critical knowledge for managers trying to maintain ungulate populations. Additionally, understanding causes of mortality and their effects on populations is vitally important to enacting meaningful and appropriate management decisions. For this project, we estimated annual survival rates of six mule deer herds in the eastern Sierra Nevada, California, USA, and calculated rates of mortality for different causes to better understand factors affecting survival of mule deer in this region.

We estimated baseline annual survival using Cox proportional …

How Relational Instruction And Caring Learning Environments Relate To Mathematics Self-Concept: A Multilevel Investigation Of The High School Longitudinal Study Of Data, Sandra J. Miles

All Graduate Theses and Dissertations, Fall 2023 to Present

The purpose of this research is to look for ways mathematics teachers can increase their students' mathematics self-concept (i.e., achievement, confidence, and interest). Many students avoid taking upper-level mathematics classes or pursuing careers in science, technology, engineering, or mathematics (STEM). However, the need for STEM professionals in the workforce will increase in future years and there is a projected shortage of students who will be trained to fill the demand. This research proposes that mathematics teachers can actively work to improve their students' self-concept by providing a caring and emotionally supportive learning environment as well as providing instruction that builds …

Movement Behavior And Habitat Selection Of Juvenile Mountain Lions (Puma Concolor) During Three Behavioral States Of Dispersal, John F. Randolph

All Graduate Theses and Dissertations, Fall 2023 to Present

Juvenile dispersal, the act of moving from their natal range to the place where they eventually reproduce and establish an adult home range is hazardous. Juveniles must travel and find food across unfamiliar landscapes, where they must also cross roads, avoid harvest, and navigate developed landscapes. Despite the inherent dangers of dispersal, this demographic process is important for finding suitable mates and reducing inbreeding depression. Wildlife conservation concerns arise when individuals are unable to disperse due to a loss of connectivity, as this can negatively impact population demographics and genetic diversity. We explored the effects of hunting and human-developed landscapes …

The Effect Of Seed Mix Density And Composition On Wetland Plant Community Assembly In The Great Salt Lake Watershed, Elana Feldman

All Graduate Theses and Dissertations, Fall 2023 to Present

Wetlands provide important ecosystem services to society but are in danger across the globe partly due to the spread of invasive species (species that harm humans, the environment, or the economy). One species, Phragmites australis, is a widespread invader across the country, including in the wetlands of the Great Salt Lake and Utah Lake. Phragmites australis spreads widely and quickly outcompetes native species. In places where P. australis has already been removed, seeding wetlands helps block P. australis from returning. Native plants’ ability to prevent invasive species from entering the community is affected by many factors, but two that …

Resilience Of Birds To Habitat Change: Identification Of Interspecific Variation In Avian Resilience And Its Possible Mechanisms, Amanda L. Hayes-Puttfarcken

All Graduate Theses and Dissertations, Fall 2023 to Present

Humans have been changing landscape features that are important to birds for many years. This is a problem because 3 billion birds have been lost since 1970 and this affects our lives every day, since birds help us by pollinating our crops and controlling pests, among other services. It is critical that we understand which birds are most susceptible to a changing landscape so that we can slow their decline. Understanding birds’ resilience to these habitat changes can help wildlife managers make better informed decisions for birds living in a changing world. We looked at which bird species are present …

Revegetation Strategies For Native Wetland Plant Restoration In The Face Of Phragmites Australis Reinvasion And Hydrologic Extremes, Maddie Houde

All Graduate Theses and Dissertations, Fall 2023 to Present

Reestablishing native plant communities in degraded habitats through seeding or planting ("revegetation") is a necessary step to restore ecosystems and their functions (e.g., supporting biodiversity, nutrient cycling, etc.). Globally, wetlands have suffered high rates of degradation and also experience numerous invasions. Invasive species are those that cause environmental, economic, or societal harm. Phragmites australis is a widespread invasive species that outcompetes native plants and reduces habitat diversity. Reestablishing native plant communities can limit P. australis invasion, yet effective methods to do so remain somewhat untested in wetlands. Additionally, stressful environmental conditions can increase plant mortality in revegetation efforts. In semi-arid …

Experimental Nonnative Wood Addition Enhances Instream Habitat For Native Fishes And Investigating Dryland River Alterations, Benjamin J. Miller

All Graduate Theses and Dissertations, Fall 2023 to Present

The rivers of the Colorado River Basin (CRB) have been degraded by human activities such flow regulation, water overallocation, and the introduction of invasive riparian vegetation (primarily tamarisk tamarix spp. and Russian olive Elaeagnus angustifolia). These stressors have resulted in widespread habitat loss and simplification, which is a major contributor to the endangerment of native fishes in the CRB.

The objectives of this study were to 1) assess the effectiveness of enhancing native fish habitat by experimentally adding cut wood from nonnative Russian olive to the San Juan River, a highly degraded dryland river, and 2) determine the …

A Framework That Explores The Cognitive Load Of Cs1 Assignments Using Pausing Behavior, Joshua O. Urry

All Graduate Theses and Dissertations, Fall 2023 to Present

Pausing behavior in introductory Computer Science (CS1) courses has been related to a student’s performance in the course and could be linked to a student’s cognitive load, or assignment difficulty. Having an objective measure of the cognitive load would be beneficial to course instructors as it would help them design assignments that are not too difficult. Two studies are presented in this work. The first study uses Cognitive Load Theory and Vygotsky’s Zone of Proximal Development as a theoretical framework to analyze pause times between keystrokes to better understand what types of assignments need more educational support than others. The …

The Influence Of Individual Strategies On Cougar Ecology: Insights From Predation, Space Use, And Reproduction, Kristin Nicole Engebretsen

All Graduate Theses and Dissertations, Fall 2023 to Present

Carnivores are ecologically important to global ecosystems because they interact with their prey species and other carnivores in a variety of ways. Many carnivores have suffered habitat loss and persecution by humans, which has led some populations to become imperiled or locally extirpated. Despite these challenges, cougars (Puma concolor) continue to exist across North, Central, and South America. They exhibit behavioral adaptation across their wide range, thriving in terrain that ranges from temperate forests, to steppe scrub, to rainforest, to rugged deserts. Across these diverse ecosystems, cougars can successfully establish territories, hunt prey, and raise young to persist …

Informing Control Efforts For A Prolific Invasive Species: Characterizing Common Carp Spatio-Temporal Distribution And Evaluating The Impacts Of Gear Selectivity In Utah Lake, Rae Fadlovich

All Graduate Theses and Dissertations, Fall 2023 to Present

Management programs that aim to reduce the consequences of invasive species are often challenged by populations that can rapidly recover from removal efforts. Selectivity, the relative impact of harvest on different size classes, can contribute to population recovery when younger fish are not effectively targeted. In Utah Lake, the location of one of the world’s largest freshwater fish control programs, managers have been attempting to control the common carp (Cyprinus carpio, hereafter “carp”) population since 2009 but efforts have been hindered by the use of selective fishing gears. I conducted a lake-wide field study to gain insights into …

Nutrient Management Of Cannabis In Controlled Environments, Julie A. Hershkowitz

All Graduate Theses and Dissertations, Fall 2023 to Present

Cannabis has been cultivated for millennia as a multipurpose crop for food, fiber, and medicine. Secondary metabolites called cannabinoids, including cannabidiol (CBD) and the psychoactive Δ-9 tetrahydrocannabinol (Δ-9 THC), are responsible for the medicinal properties of cannabis. The intoxicating nature of THC resulted in legislation prohibiting the possession and production of cannabis within the United States during the 20^th century. As a result, research programs on cannabis production were halted at most institutions. In recent years, cannabis production has become widespread within the US as a result of increasing legalization. However, modern cannabis production nutrient management programs often include …

Novel Kinetic Description Of Real-Time Polymerase Chain Reaction Characterizes Interrelated Effects Of Sample, Master Mix, And Cycle Time, David Tafur

All Graduate Theses and Dissertations, Fall 2023 to Present

Real-time quantitative polymerase chain reaction fluorescent curves are influenced by the quantification method, template length, primer sequence, polymerase activity, reaction conditions, and unwanted side reactions. Interpretation of these curves depends on understanding the subjacent mechanisms by which those factors can alter the curve profile, particularly on highly diluted analytes or impure samples. However, such factors are individually described today, or their interplay is not fully developed. The present work examines the effect of primer dimer formation and extension, resource competition, template reannealing, and polymerase thermodegradation, in addition to novel descriptions of polymerase competitive inhibition, extended primer amplification, and the probability …

An Expansive Framing Intervention And Its Influence On Nursing Students' Perceptions Of Value For Mathematics, Kimberly Evagelatos Beck

All Graduate Theses and Dissertations, Fall 2023 to Present

Nurses regularly use mathematics on the job, yet they often do not view their work as mathematical. This may indicate a lack of transfer from the nursing school mathematics context to nursing practice. Further, nursing students often perceive very little usefulness and relevance for learning mathematics beyond simple calculations. Expansive Framing (EF) is a theory and instructional technique that has been shown to foster transfer by establishing intercontextuality, or connections made between disparate contexts. This research explored whether creating intercontextuality created through broad framing also improved perceptions of mathematics value and transferability, and how intercontextuality functioned as the driver of …

Analysis Of Water Pollutants Across Greater Omaha, Desmond Marshall

Theses/Capstones/Creative Projects

Water is a finite resource, and most water has the potential to become contaminated in sitting bodies. Health complications have an increased chance of occurring when these water sources have pollutants. Preventative and treatment methods are components of the legislation put in place to prevent concentrations from reaching levels capable of causing these ailments. However, sites sometimes fail to keep them under tolerated levels. This study is intended to examine if several locations across Omaha are keeping pollutants under legal concentrations and analyze any trends in the data. Locations (n=10) are sampled twice, with exactly two-weeks between collections. The water …

Development Of A Solution Concept Inventory For The High School Chemistry Classroom, Grace Tetschner

Theses/Capstones/Creative Projects

Many high school chemistry students struggle to learn the chemistry of solutions because they hold alternate conceptions—beliefs that differ from scientifically accepted ideas—related to the topics covered in a traditional solution unit. For this reason, high school chemistry teachers would benefit from the development of a Solution Concept Inventory (SCI)—a multiple-choice assessment that could be used in the high school classroom to identify student alternate conceptions on the concept of solutions. In this study, common solution-related alternate conceptions were identified, items for an SCI were developed, an analysis was performed to determine the quality of the items, and validity evidence …

Optimization Of Tyrosine Hydroxylase Antibody For Immunohistochemistry Fluorescence Detection In Zebrafish (Danio Rerio), Madison Thurber

Theses/Capstones/Creative Projects

Dopamine is an important neurotransmitter produced through the catecholamine synthesis pathway that affects brain activity. Unregulated dopamine levels can lead to various diseases such as Parkinson’s Disease or attention deficit hyperactivity disorder (ADHD). Optimization of an immunohistochemistry protocol will allow for the quantification of tyrosine hydroxylase antibody, which indirectly allows for dopamine quantification in dopaminergic regions within the brain. However, the antibody concentration to give the optimal signal-to-noise ratio in IHC varies across studies. Through this experiment, I determined the concentration of tyrosine hydroxylase (TyrH) antibody for immunohistochemistry that gave the best signal-to-background noise ratio within several known dopaminergic regions …

Cerebral Venous Sinus Thrombosis (Cvst): A Retrospective Study, Nia Acharya

Theses/Capstones/Creative Projects

This retrospective study investigates the long-term management of Cerebral Venous Sinus Thrombosis (CVST) in 51 patients over a 3-month follow-up. The analysis covers demographics, risk factors, CVST presentation, associated diseases, thrombophilia, laboratory results, and antithrombotic treatments. CVST, a rare thrombosis of dural/cerebral sinuses, poses life-threatening risks with an annual incidence aligning with literature, notably affecting young individuals. Underlying causes range from rare disorders to common triggers, complicating diagnosis, especially during pregnancy. Imaging techniques aid diagnosis, with systemic anticoagulation preferred despite bleeding risks. Noteworthy findings include a higher incidence in women, predominantly presenting with headaches. Two cases of vaccine-induced immune thrombotic …

Characterizing The Role Of Pa5189 Of Pseudomonas Aeruginosa In Deletion And Overexpression Mutants, Seh Na Mellick

Theses/Capstones/Creative Projects

In the context of rising multidrug resistance in biofilm-forming pathogens like Pseudomonas aeruginosa, this study investigates the role of the understudied transcription factor PA5189 in antibiotic resistance and biofilm formation. PA5189 deletion and overexpression mutants were created in a parent P. aeruginosa strain using pEX18Tc-based recombinant suicide vectors, with genotypic verification of putative triparental conjugants achieved through restriction digestion and PCR. The study revealed that PA5189 overexpression significantly increases resistance to commonly used broad spectrum antibiotics such as ciprofloxacin and imipenem. Additionally, differential expression of PA5189 was found to notably affect biofilm formation, with variations contingent on the nutrient …

Effects Various Distilled Water Brands Have On Chlorophytum Comosum., Brooke Bluhm

Theses/Capstones/Creative Projects

When first attempting home gardening, one of the challenges many home-renters are starting to face is being able to supply enough clean water to one’s plants. In order to overcome this challenge, many plant enthusiasts are utilizing prepackaged distilled water from price friendly brands available at most regional Walmart locations. With the number of choices available on the shelves of today’s grocery stores, and vague ingredient lists on packaging it can be challenging to determine which brand is actually best suited for one’s specific needs. In order to determine the best distilled water suited to grow Chlorophytum comosum, various gallons …

The Impact Of Policy And Perception On Women’S Health Since 2010, Eryn Busenbark

Theses/Capstones/Creative Projects

This project tackles the complicated relationship between policy and perception of women’s health in the last decade. This was achieved through research on existing literature and semi-structured interviews with five professionals in various areas of women’s health: mental health, public policy, sexual health education, and research. Literature reviews were conducted using University of Nebraska at Omaha Criss Library’s databases, with dozens of articles analyzed. The goal of this research was to gain an understanding of how public opinion and perceptions can sway policy, which has created challenges and consequences for women and their health.

The Effect Of An Oak Savanna Habitat Restoration On Bat Activity In Eastern Nebraska, Aidan Hatfield, Jeremy White

Theses/Capstones/Creative Projects

Oak savanna habitat has been drastically reduced throughout the Midwest. Temperate bats generally are edge adapted and may better utilize a restored oak savanna habitat than the now common deciduous forests that replaced them. Therefore, we analyzed the activity of 7 bats native to eastern Nebraska and in the process, compared the agreement of two different programs that claim to automatically identify bat species. In order to investigate this, we placed three audio detectors within both habitats for 1 week and allowed them to record from sunset to sunrise. The data obtained was analyzed and compared between two programs, Kaleidoscope …

A Conceptual Understanding Of Concepts In Organic Chemistry, Timerra Chisham

Theses/Capstones/Creative Projects

As students continue to make the transfer into organic chemistry from general chemistry, they will have to adjust to the new type of thinking required so that they will not fall behind in understanding material and will have success in the course. For this research project, I explored which concepts taught in organic chemistry are the most difficult for students to grasp. I had two main goals for this project. The first one is the central idea that I focused on, which was to see which concepts that have been taught in Organic Chemistry 1 the students are most confident …

Problems In Power: How The U.S. And Russia Have Battled Throughout The Decades, Abbie Russman

Theses/Capstones/Creative Projects

The battle between the U.S and Russia has taken many forms throughout the years. When taking a sample of conflicts that involve the U.S. and Russia in various capacities and different points in time, certain similarities are observed. Within the individual level of conflict analysis, leaders in the U.S., Russia, and other states involved often sway between dovish and hawkish tendencies. On a domestic level, the U.S. and Russia have opposing ideologies. The U.S. values democracy and capitalism, and often supports states that lean democratically. In contrast, Russia views democracy as a threat and supports states that value protectionism and …

Methamphetamine Activates Microglia And Increases Production Of Pro-Inflammatory Chemokine C-C Ligand 2, Colton Bredenkamp

Theses/Capstones/Creative Projects

Methamphetamine (meth) use continues to increase in the United States despite the apparent health risks that involve neuroinflammation and brain damage. Because neuroinflammation underlies several substance-use and neurological disorders, we investigated whether microglia, the resident immune cells in the brain, are activated and consequently increase production of pro-inflammatory chemokines such as C- C chemokine ligand 2 (CCL2) in the presence of increasing amounts of meth. To address this, we exposed immortalized microglia cells (IMG) isolated from mature mouse brains to increasing concentrations of meth (0, 10, 50, 100, 500 µM) and analyzed for the expression levels of activation markers (CD11b …

Determining Efficacy Of Check/Solid Stimuli Pair Vs Light/Dark Stimuli Pair For Pavlovian Fear Learning In Zebrafish (Danio Rerio), Kortney Johnson

Theses/Capstones/Creative Projects

Learning is a survival skill because it allows organisms to recall vital details about their habitats. Associative learning is another of those skills, the ability to pair two different stimuli in memory and associate them together upon recall. It has been studied in zebrafish with Pavlovian fear learning used as a methodology. Previous studies have utilized Check/Solid patterning, however, there are no published studies exploring alternative stimuli that could be effective in aversive learning. This study sought to determine if Check/Solid was the most effective at inducing aversive learning or if Light/Dark would be more efficient, due to zebrafish’s natural …