K-State Electronic Theses, Dissertations, and Reports: 2004 -
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This is the collection for doctoral dissertations and masters theses and reports submitted electronically by K-State students. Electronic submission of doctoral dissertations was required beginning Fall semester 2006. Electronic submission for masters theses and reports was required beginning Fall 2007. The collection also contains some dissertations, theses, and reports from the years 2004 and 2005 that were submitted during a pilot test project. Some items before 2004 have been digitized and are available in K-State Electronic Theses, Dissertations, and Reports: pre-2004. Check the Library catalog for dissertations, theses, and reports not found in these collections.
All items included in this collection have been approved by the K-State Graduate School. More information can be found on the ETDR Information Page. Items within this collection are protected by U.S. Copyright. Copyright on each item is held by the individual author.
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Item Open Access Bridging the Gap Between Intention and Execution: Effective Tree Planting Practices in Manhattan, KansasSaunders, GabrielleTrees provide ecological, social, health, and economic benefits in urban and suburban environments. These include stormwater management, improved perception of safety, shade, and carbon sequestration. The realization of these benefits is contingent on trees growing to their full maturity and the overall wellness of trees. Tree planting ordinances in urban design often call for a certain number of trees for each new development, but design practices and the maintenance needed to keep trees alive often fall short. Young, vulnerable trees planted in harsh environments may only survive a few years past planting, while large, established trees are removed from sites to make way for future development. As trees die due to their surrounding conditions, projected benefits—why they were required and planted—are foregone completely and cities fall short in reaching climate action goals and creating healthy living environments. Insufficient attention is being paid to the implementation and maintenance strategies needed to keep the trees alive and thriving — past the establishment period — in order to actualize their benefits. This study aims to identify those strategies, and how to implement them effectively as high-density residential zoning districts densify from single-family homes to multi-family complexes. Several methods were used to answer the following question: As two sites in Manhattan, Kansas are densified, how can street trees be implemented and maintained to maximize their longevity and receive the full benefits they can provide, based on their contextual and biophysical conditions? Three precedent study reviews are followed by an analysis of residential blocks that have experienced densification and significant tree loss in the last 10 years. Projective designs show how innovative planting strategies can be applied to two sites. Planting design guidelines for future development, including site design essentials, tree planting drawings, and required implementation and maintenance strategies, will help ensure tree health past the establishment period. Design guidelines applied to two sites in Manhattan, Kansas (which have yet to be densified, but have a potential to be based on their zoning classification and contextual patterns of the neighborhoods they belong to) will help the City of Manhattan and Kansas Foresters as they review development proposals. This study builds upon past research and practices to identify when specific planting design, implementation, and maintenance strategies must be applied, and provides a framework that can be used in Manhattan, Kansas and other densifying urban landscapes.Item Open Access Connecting postsecondary quality of life to promises of IDEA: An issue of educational equityHeiman, MargaretThis mixed methods study on postsecondary outcomes for individuals with disabilities focused on the experiences of young adults with intellectual and developmental disabilities (IDD) and significant disabilities from their perspective. The research questions include understanding their overall quality of life (QOL), the supports, services, and experiences they received during Individuals with Disabilities Education Act (IDEA) Part B, and how these experiences contributed to their current QOL as young adults. The study used a constructivist and pragmatic worldview, focusing on the importance of understanding IDEA supports and services from the perspective of individuals who received them. The research design involved collecting both qualitative and quantitative data, with the qualitative phase informed by the quantitative phase. The research was completed in two phases, with the first phase focusing on the participants' overall QOL rating using the Wisconsin Quality of Life Survey and the second phase on the qualitative aspects of their QOL. The research provides a more comprehensive understanding of the experiences and perspectives of young adults with disabilities in postsecondary education. Ultimately, the study participants emphasized the challenges they face as young adults transitioning from IDEA Part B to adulthood. They stressed the importance of social networks and the need for individualized education plan (IEP) teams to support social nuance and meaningful connections throughout all their IDEA journey. The findings also bring to light the need for specialized ages 18-21 special education services, which are crucial for cultivating employability skills and life competencies. The findings in this study highlight the need for bridging the gap between policy and practice, which would empower young adults with disabilities to chart their own destinies with autonomy and agency. By bridging this gap, we can better create a future where individuals with disabilities are not just survivors but architects of their destinies, with dignity, in a place where opportunities abound.Item Open Access Human-environment interactions in rural and agricultural communities: Identifying opportunities for sustainability efforts using quantitative, qualitative, and GIS methodsAmariah, FischerThe United States agriculture industry, especially in the Midwest, is expected to be adversely impacted by the consequences of climate change, with temperature and precipitation changes making sufficient crop production exceedingly difficult to achieve. Further, the agriculture industry is also a significant contributor to climate change and faces a rising global population with increased food demands. The combination of these circumstances creates a context in which members of agriculture and food systems must adapt to a changing climate to increase food production while simultaneously rethinking traditional approaches to agriculture to mitigate contributions to climate change. This makes the study of agricultural sustainability, and the sustainability of the many rural communities that rely on agriculture, essential for the future of our planet. However, given the complex nature of problems in agricultural and rural sustainability, solutions often require an interdisciplinary approach and the consideration and integration of both human and natural systems. The goal of this research was to contribute to agriculture and rural sustainability by conducting three different research projects that each focused on an area of agricultural or rural sustainability. In chapter three, we investigate how the physical water environment shapes water conservation norms among farmers in the High Plains-Ogallala Aquifer, the largest source of groundwater in the United States. These questions were approached in terms of cultural adaptation to the physical environment, comparing irrigators with dryland farmers using survey and environmental data. I used the values-beliefs-norms (VBN) framework to develop a conceptual model to integrate the physical water context as an exogenous explanation of water conservation norms. Grouped simultaneous equation models indicate a limited form of cultural adaptation in the region that, from a biological perspective, could be considered evidence of mal-adaptation. Both irrigators and dryland operators in more water-rich environments hold stronger water conservation norms and those in more arid environments hold weaker water conservation norms. For irrigators, the relationship between the water context and norms is partially mediated by worldviews where irrigators in more water scarce contexts tend to hold more ecocentric worldviews that motivate conservation. The findings suggest the importance of considering farmers’ practices (dryland farming or irrigation) and their places (physical water context) in shaping their decision-making in an integrated socio-ecological context. In chapter four, measures of rurality were investigated. Government agencies and researchers often rely on quantitative measures to map where rural places are and who belongs to rural communities. To better understand the consistency, or lack thereof, across different quantitative rural measures, we compare four common measures applied at the county level for the contiguous United States. My purpose was to (1) quantify and map the degree of rural agreement among these selected rural measures and (2) describe key characteristics of counties classified as rural through urban. Comparing different measures yielded little agreement on rural places with consensus achieved for only 114 of 3,108 counties (3.7%). County variables contributing to good separability in rural to urban classifications included remoteness, population density, percent of the population aged 65 and over, employment in the agricultural sector, and both developed and grassland landcover. Closer examination of the underlying characteristics of the 114 consensus rural counties provides an opportunity to reflect on the nature of popular rural measures and the variables they use. If these counties are not representative of how researchers conceptualize “rural” across US regions, it is motivation for working toward new and/or spatially adaptive rural measures that better represent the communities that policy and research intends to help. In chapter five, the process of regenerative agriculture adoption was examined. To address the negative environmental impact of industrial agricultural practices, research has been dedicated to the adoption of regenerative agriculture (RA) as it has been shown to reduce agriculture’s overall contribution to climate change and better prepare farming operations for future changes in climate. The adoption of RA practices has been linked to systems thinking, with farmers employing regenerative farming practices reporting higher engagement with systems thinking. This study interrogates this relationship further by examining how industrial and regenerative farmers demonstrate systems thinking skills. To do this, sixteen cognitive maps of individual farm systems were collected through qualitative interviews with farmers in central Kansas. These cognitive maps were then used to compare systems thinking skills across farmers employing practices along the spectrum of industrial to regenerative. Results showed that regenerative farmers demonstrated more developed systems thinking skills when compared to industrial farmers. Further, the cognitive maps of regenerative farmers prioritized internal and ecological farm factors, particularly soil health, while those of industrial farmers emphasized external and human-driven farm factors.Item Open Access Extrusion-based 3D Freeze Printing of Multi-functional AerogelsYang, GuangAerogels constitute a unique class of synthetic porous ultralight materials, derived from gels where the liquid component is substituted by gas while retaining the gel structure. Their outstanding material properties, including high porosity and low density, have spurred exploration across various domains such as catalysis, thermal insulation, solar energy utilization, piezoelectricity, energy storage, low-temperature glass formation, sensors, adsorption, and photocatalysis. The integration of 3D printing technology into aerogel production offers unprecedented design flexibility and the capacity to customize material characteristics. Nevertheless, prevailing 3D printing methods for aerogels encounter challenges concerning printability, microstructure regulation, and macrostructure manipulation. To tackle these obstacles, a novel 3D printing method known as 3D Freeze Printing (3DFP) has been developed internally, merging freeze casting with additive manufacturing techniques. This approach facilitates the precise fabrication of tailored geometries with controlled microporous structures. Previous investigations have primarily focused on a limited range of materials such as graphene and silver nanowires, necessitating exploration into diverse materials to unlock the full potential of 3DFP. Additionally, comparative evaluations between multifunctional aerogels produced via 3DFP and those from conventional methods remain unexplored. Former studies predominantly relied on optical imaging for 3DFP characterization, constraining insights into material deposition and solidification. Systematic analysis of the extrusion process and quantitative assessment pose considerable challenges but are crucial for optimizing 3DFP processes across industries like chemical, machinery, electronics, aerospace, and biomedical engineering. This thesis addresses these gaps by fundamentally studying the extrusion-based 3DFP method and its potential applications. After a comprehensive review of freeze casting and current extrusion-based 3D printing techniques, precedes investigations using X-ray synchrotron micro-radiography from leading facilities like the Advanced Photon Source and SLAC National Accelerator Laboratory are presented. These experiments provide real-time insights into material behavior during freeze casting and 3DFP processes. Moreover, the fabrication and characterization of novel cellulose nanocrystal (CNC) aerogels using 3DFP demonstrate exceptional acoustic absorption and mechanical properties tailored through freezing direction modification. These nano-cellulose aerogels present promising applications in ultra-lightweight sound absorption devices for aerospace use. Additionally, this thesis extends to extrusion-based 3D printing of zirconium carbide (ZrC) nuclear fuel cell structures, reporting the influence of additives like Nano Crystalline Cellulose (NCC) and Vanadium Carbide (VC) through rheological and mechanical testing. Integrating additive manufacturing with advanced materials like ZrC and tailored additives marks a significant stride towards sustainable propulsion systems for future space missions. In conclusion, this thesis delves into the fundamental aspects and practical applications of extrusion-based 3DFP, paving the way for optimized aerogel production across diverse industries and advancing materials science for futuristic technologies.Item Open Access Foundational Sorghum Kombucha Research in Swine: Preference, Cognition, and Social TestingNelson, CatherineThe use of swine has the potential to extend greatly beyond their current facets of utilization. The combined advancements in the methodology of behavioral collection and precision animal technology allow for the refinement of swine testing procedures regarding both efficiency and welfare. This thesis will introduce the development of procedures using a novel 3-pod maze to assess preference as well as the social impacts of an in-pen cognitive feeding test. Study 1 was conducted to measure pig preference for three different strains of fermented sorghum tea utilizing a three-pod radial maze. The first phase served to eliminate neophobia by acclimating in pairs with each bowl containing a control isocaloric solution of sugar water (positive control). The second phase conditioned the pigs individually using the positive control in one arm and distilled water (negative control) in the other two arms. The first experimental phase consisted of testing of testing the preference of three different versions of fermented sorghum tea. Each solution utilized a different strain of commercial sorghum: 1) Raw white, mild flavor profile, 2) Raw sumac, medium flavor profile, and 3) Roasted sumac, bold flavor profile. There was no clear preference between strain so in the second experimental phase the three teas were mixed and put into one pod on a rotation with the positive and negative control. Results showed that the 3Tea was the most desirable treatment as it had the highest consumption volume over the positive and negative controls. Total duration spent in the pod as well as duration of head over bowl behaviors was greatest for pods containing the 3Tea mixture and lowest for the negative control. In conclusion, the pigs preferred the 3Tea mixture over a sweetened water. This study provides evidence that pigs do not have a strong aversion to novel, sour, and bitter flavors as previously thought. Study 2 was conducted to test a prototype for an in-pen cognitive feeding task. Pigs were exposed to a cognition task that required them to push a series of paddles to receive a food reward. After a conditioning phase the pigs were randomly assigned a pattern for individual acquisition. The pattern consisted of either alternating, inner or outer paddles. Once the pigs completed the individual acquisition phase they were exposed to the test with the same pattern in pairs. Performance on the task was assessed through latency, duration, and frequency measures. The paired phases allowed for the analysis of social hierarchy and cooperation on task performance with an end goal of assessing if sociality and format impacted test performance. Social behaviors assessed included advance, retreat, and neutral. Frequency data for these social behaviors was utilized to calculate dominance indices and determine social status. Format did not have a significant impact on overall performance. However, the outside format had the highest rate of correct paddle contact leading to the extrapolation that it was the easiest for the pigs to uptake. Submissive pigs also had a significantly higher number of overall paddle presses as well as presses on the correct paddle, indication higher motivation and contrafreeloading status when faced with a cognitive task. Dominant pigs were likened to freeloaders as their higher social status was their main tool for meal acquisition. The results of these studies are assessed together through hematology results reported in the final chapter. Blood was collected from all pigs pre and post study. Dominant and submissive status assigned in study 2 was used to assess hematological differences between pen-mates and the potential health benefits of the fermented sorghum tea consumption. Dominant pigs showed higher levels of plasma glucose, triglycerides, and cholesterol. Dominant pigs also had higher overall body weight correlating with higher fat and inflammatory markers seen in the blood results. Despite an increase in size dominant pigs experienced a decrease in all of these variables post-study, rendering further investigation of the effects of fermented sorghum essential. The development of procedures for these studies will assist in the refinement and ultimate advancement of the role swine can play within the scientific community. A refinement of behavioral and cognitive data collection will create for more efficient and ethical housing of swine in production and translational studies. The methodology outlined within this thesis can be used as a guide for future studies assessing swine preference, cognition, and social hierarchy.Item Open Access Effects of U.S. inflation rates on Fruitful Rim beef cow-calf production input costsBrauman, CallieThe United States relies on the beef industry for both import and export beef; however, the overall U.S. cattle herd size is the lowest it has been since 1954 due to wide variety of factors discussed in this analysis. The United States is one of the top beef exporters in the world, providing beef to many countries. This is also a crucial area of income for the U.S. Due to the increased cost of production and lower profit margins, there have been many herd liquidations across the country, having a negative impact on the national herd size. There are many factors that have affected beef cattle production's overall profitability within the last several years, including but not limited to weather, lack of succession planning, age of cattle producers, global events, and consumer habits. With an increasing inflation rate, many producers are unable to continue beef cattle production due to their inability to financially afford the resources and supplies needed to produce beef cattle, while also providing for their families and covering the increased cost of living. Aside from these things, many cattle producers, as well as other agricultural producers have always been able to rely on lenders to provide capital, allowing them to cover their operating costs until they receive payment for their product. It is the goal of this study to provide insight through analysis determining the effects of United States inflation on cow-calf production input costs within the Fruitful Rim region. This study uses data analysis through both correlation and regression methods. This analysis focuses on data pertaining to cow-calf producers within the Fruitful Rim Region, collected annually by the U.S. Department of Agriculture and the National Agriculture Statistics Services. The data included numerous categories of input costs as well as the Consumer Price Index (CPI) from 1996 to 2022 to analyze the correlation between the input costs and in inflation rates. Through this analysis it was discovered that certain input costs are more affected by changes in inflation than others. For example, there was little to no correlation between the CPI and vet/medicine costs; however, purchased feed cost was directly correlated with the CPI. Purchased feed costs increased $0.55 per head with one unit of increase in the CPI. Cattle for backgrounding were inversely related to the CPI and showed a $0.46 decrease per head of cattle when there was one unit of increase in the CPI. Producers can focus on more affected areas and be less concerned about costs that may not change much. For example, there is no direct correlation between veterinary and medicine costs and the CPI. Therefore, when inflation is increasing this would not be a cost to be as concerned with; however, the results show that purchased feed costs increase with CPI increases. Producers can focus on alternative means of feed, such as grazed feed, to save input costs when inflation is increasing. The information discovered and summarized in this study provides guidance to producers interested in making educated decisions in different economic situations. As the data shows, there are some categories of input costs that are highly affected by changes in inflation; however, there are others that are not affected at all.Item Open Access The effects of transportation on wheat prices to local Kansas wheat farmersShayna, DeGrootWheat farmers in Kansas play a critical role in helping feed the world. They work under volatile conditions that are unpredictable each year such as weather, basis, prices and yield. There are many factors that play into the volatility, specifically for basis prices, like transportation. This can be affected by the price of diesel, rail, ocean freight and futures price. While diesel is a major transportation input on farm operations and in grain transport, costs such as ocean freight and rail for exported commodities can be overlooked. Ocean freight plays a factor as roughly 50% of the wheat grown in Kansas is exported. The goal of this thesis is to examine how prices of diesel, rail, ocean freight and futures affect wheat basis for local wheat farmers across Kansas. The data for this study were collected from AgManager.info, the United States Department of Agriculture Agricultural Marketing Service, the United States Energy Information Administration and the Federal Reserve Economic Data. Data were collected as monthly averages from 2015 to 2023, a nine-year span, which included diesel prices, rail tariff rates, ocean freight rates, wheat futures prices and basis from elevators across Kansas including 21 towns from three counties in each of the seven agriculture districts. Elasticity has some variability across the models. Combining all seven districts, results indicated that on average, a 1% increase in futures would result in a 0.47% decrease in basis, a 1% increase in ocean freight would result in 2.47% increase in basis, a 1% increase in diesel would result in a 0.89% decrease in basis and a 1% increase in rail would result in a 0.12% increase in basis. Farmers should look at futures price, ocean freight, local diesel price and rail tariff rate before making decisions at elevators as all four factors affect wheat basis, with futures and diesel commonly decreasing basis and ocean freight and rail tariff rates commonly increasing basis. By looking at these factors, it will help farmers determine whether to sell their wheat or wait.Item Open Access Effects of flow training on movement, survival, and habitat associations of age-1 Colorado pikeminnow stocked in the San Juan River, Utah, and New MexicoCleveland, JohnStocking of hatchery-reared fish is an increasingly important management action to conserve and restore native fish populations. Colorado pikeminnow (Ptychocheilus lucius) was historically abundant throughout the Colorado River basin until the construction of dams and introduction of nonnative species caused a rapid decline and federal listing as endangered in 1973. Following the presumed extirpation of pikeminnow in the San Juan River in the late 1990s, a stocking program was developed in 2003. Due to an increasing adult abundance and potential for spawning, stocking protocols were changed from stocking young of year to age-1 pikeminnow with passive integrated transponders (PIT) tags to distinguish wild spawned and hatchery reared individuals. The addition of unique tags also allowed for hatchery experimentation such as flow training which was implemented in 2022 and 2023 to increase the survival of stocked age-1 pikeminnow. I used radio telemetry to compare movement, survival, and habitat associations among flow-trained and different size classes of non-flow-trained pikeminnow. We also used PIT tags implanted in stocked pikeminnow to evaluate differences in detection rates across treatments. The mean rate of movement for radio-tagged pikeminnow was similar across treatments (-0.08 ± 0.48 km/hr). At the conclusion of 60 days, no control (0%), one flow-trained (3.3%) and 12 larger pikeminnow (34.3%) were detected and determined to be alive and within our study reach across both years. One individual from the radio-tagged flow-trained group was detected 255 river kilometers downstream approximately five days post stocking in 2022 (rate of -2.13 km/hr), demonstrating the ability to move long distances following stocking. Effects of terrestrial predation was observed in both years with 11 radio transmitters and 59 PIT tags found on dry land within the river corridor. Another radio transmitter was triangulated in a great blue heron (Ardea herodias). Overall, results suggest stocked pikeminnow dispersed quickly downstream; flow-trained pikeminnow prior to stocking did not increase retention of radio tagged individuals; and terrestrial predators may be a large source of mortality. Increasing the duration or velocities of flow training, prey training, or using alternative stocking sites may reduce losses due to predators and emigration.Item Open Access Communicating climate-change impacts to youth: A social influence theory perspectiveCannon, LaurenClimate change is known to have severe impacts on Earth’s temperature, organisms, human health, and habitats. Despite overwhelming scientific evidence, many individuals hold misbeliefs about climate change. Misbeliefs can prevent policy changes or environmental action to reduce climate-change impacts from taking place. Previous scholars have addressed the potential causes behind these misbeliefs, including misinformation, confirmation bias, and tribalism. Since current solutions have not yet significantly reduced these misbeliefs or their causes, this report explores the issue using a social influence theory perspective. By synthesizing literature on social influence theory, climate-change communication, and the use of youth groups and activities for education, it is concluded that communicating to youth groups and their leaders about climate-change impacts could produce the greatest change in reducing misbeliefs. This is due to the combination of normative social influence, leadership and mentorship influence, and healthy environments in youth group structures. These findings inform a communication plan for reducing misbeliefs about climate in youth groups in low socioeconomic areas of Kansas. By educating youth about climate change, we can significantly reduce misbeliefs overall through generational replacement and allow more policy changes and environmental actions to be implemented to reduce climate-change impacts.Item Open Access Use of artificial intelligence to locate and treat weeds in Midwestern United States corn (Zea mays) and soybean (Glycine max) cropping systemsBarnhart, IsaacSite-specific weed management (SSWM) is defined as the process of managing weeds where they are growing as opposed to treating the whole field and treating areas with no weeds. Artificial intelligence (AI), the process of creating intelligent machines, has become a part of everyday life in modern society. Utilizing convolutional neural networks and object detection algorithms, weeds can be distinguished from crops, and herbicide applications can target weeds where they are growing. The objectives of this dissertation were to 1) train open-sourced object detection algorithms to detect in central Kansas soybean (Glycine Max [L.] Merr.) fields, focusing on Palmer amaranth (Amaranthus palmeri S. Watson, henceforth denoted as A. palmeri), 2) determine herbicide efficacy and cost savings of SSWM herbicide applications using a ONE SMART SPRAY research sprayer, an intelligent dual-boom sprayer using AI technology to locate and spray weeds growing within crops, and 3) compare traditional broadcast (BCST) applications with spot-spray (SS) herbicide applications using a commercial-sized ONE SMART SPRAY sprayer. Images were obtained from two soybean fields in 2021 containing A. palmeri infestations and were annotated with bounding boxes to identify both A. palmeri and soybean plants. In this study, the YOLOv5 object detection algorithm was identified as having the highest mean average precision scores and was therefore selected for further analysis. The precision, recall, and F1 evaluation metrics found for the test image dataset was 0.71, 0.70, and 0.71, respectively. Regression analysis revealed that our trained YOLOv5 model evaluation metrics were higher when identifying A. palmeri plants 2 cm in height at low plants m-2. For the second objective, corn (Zea mays L) and soybean field trials were conducted in Manhattan, KS and Seymour, IL with the research-sized ONE SMART SPRAY. Simultaneous herbicide applications of residual BCST + foliar SS, base-rate foliar BCST + SS “Spike” rates, and SS only were compared in corn (Zea mays L.) and soybean trials. Specific SS thresholds tested included an herbicide efficacy, balanced, savings, and traditional BCST applications were tested for comparison. Results showed that both residual BCST + foliar SS and “Spike” approaches provided weed-free area not different than traditional broadcast applications, in many cases. The greatest savings were achieved by SS only applications, but weed-free area was almost always significantly less than for other treatments. Simultaneous BCST + SS of soil residual and foliar herbicides, respectively, provided the most weed-free area with the greatest cost savings for both crops. Thirdly, we tested a commercial-sized ONE SMART SPRAY and compared traditional broadcast applications with SS only and simulated two-boom/two-tank applications using the foliar base rate + “Spike” approach. Treatments included SS only, low rate BCST + high rate SS, and high rate BCST + low rate SS applications. Results indicated that high rate BCST + low rate SS applications provided the highest weed-free area, but savings were not different from a broadcast application in soybeans. In corn, thresholds were not different, but both applications with BCST applications demonstrated greater weed-free area than SS only treatments. Overall, this research demonstrated that 1) open-sourced object detection algorithms can be custom trained to identify A. palmeri in soybean crops, with opportunities to train and identify other weed species in other crops, 2) intelligent AI sprayers show potential in providing weed-free area comparable to traditional BCST applications, especially systems that utilize two-tank/two-boom technology for simultaneous BCST and SS applications, and 3) herbicide costs were significantly reduced for SS applications compared to traditional BCST applications.Item Open Access Assessing the impact of cover crops on soil health in a long-term no-till rotation: A case study from Northeast KansasGrünberg, JessicaMaintaining soil health is essential for sustaining agricultural productivity and ecosystem resilience. Conservation agriculture, known for minimal soil disturbance and permanent soil cover, offers strategies to address soil degradation associated with conventional management practices like conventional tillage and prolonged fallow periods. Despite its recognized benefits, there are concerns regarding potential drawbacks, such as nutrient stratification and soil acidification over time. Cover crops have emerged as a promising tool for enhancing soil health, however, long-term effects of cover crops on soil proprieties under no-till management and various intensification schemes remain to be fully understood. This study aimed to assess (i) how different preceding cover crop types and varying nitrogen (N) rates applied to corn influence pH, soil organic carbon (SOC), and nutrient concentrations and distribution in the soil profile, and (ii) the effects of different intensification strategies on soil biological indicators and their persistence throughout subsequent years of the rotation. A long-term experiment consisting of a no-till three-year wheat (Triticum aestivum L.), sorghum [Sorghum bicolor (L.) Moench], soybean [Glycine max (L.) Merr] rotation was established in 2007 near Manhattan, Kansas. Sorghum was replaced with corn (Zea mays L.) in 2020. The different fallow managements imposed between wheat and corn included chemical fallow (CF), double-crop soybean (DSB), and four cover crop treatments. To meet the first objective of this study, soil profile samples were collected in 2021 and 2022 after corn harvest to determine how different fallow management preceding corn and different N rates applied to corn affect soil pH, SOC, Total N, and Melich-3 Phosphorus (P) concentration and their distribution in the soil profile. Nutrient concentrations were higher near the soil surface, and pH tended to decrease in the upper soil layers. Differences among the fallow management options were most pronounced at the 0-5 cm depth for all measurements. Soil organic carbon was enhanced by adding cover crops and DSB compared to CF. Similarly, Total N was greater whenever any cover crop treatment or DSB replaced a portion of fallow. Soil pH increased with cover crops and DSB and decreased with higher N rates only at surface layers. Phosphorus concentrations decreased with DSB and remained similar to CF for most cover crops. Overall, cover crops and intensification alternatives like double-cropping showed potential to improve SOC and N levels in the soil surface and enhance its capacity to buffer changes. Further research should address managing the negative impacts of P stratification on soil health and water quality. To meet the second objective, soil samples were collected in May 2022 and April 2023 in all crop phases, to capture the effect of fallow management on biochemical indicators at different time intervals after cover crop termination: immediately after cover crop termination (T0), in corn stubble one year after cover crop termination (T1), and in growing wheat two years after cover crop termination (T2). Samples were collected at the 0-5 cm depth and analyzed for the following biochemical indicators: POXC, soil protein, glucosidase and glucosaminidase activities, and soil respiration. Cover crops positively impacted all soil biochemical indicators immediately after cover crop termination (T0), increasing POXC by 30%, soil protein by 17%, glucosidase activity by 63%, glucosaminidase activity by 82%, and soil respiration by 116% compared to CF. In general, cover crops with larger biomass inputs provided the largest increases in biochemical indicators. Double-crop soybeans exhibited indicator levels similar to or slightly greater than CF, yet lower than most other cover crops. These responses were most evident immediately after cover crop termination and persisted to some extent for one year thereafter. However, the responses diminished over time and were not detectable two years after cover crop termination. This information could assist in determining how frequently cover crops should be integrated into cropping systems and identify the most effective mixtures and species for sustaining soil health benefits over time.Item Open Access Synthesis, characterization, and electrocatalytic hydrogen evolution of transition metal Schiff-base calixpyrrole complexes with pendant hydrogen bond donorsTrowbridge, LoganThree novel calixpyrrole complexes with pendant hydrogen bond donors were synthesized via the condensation of 5,5’-diformyl-2,2’-diphenyldipyrromethane and an aniline precursor. Single crystal X-ray diffraction revealed that these complexes displayed distorted square planar geometries, and significantly the pendant groups remained uncoordinated from the metal. Electrochemical studies, along with density functional theory (DFT) calculations, indicated that the ligand exhibited redox non-innocence as evidenced experimentally by similar irreversible oxidations in both the ligands and complexes. Electrochemical analysis in the presence of p-toluenesulfonic acid generated an irreversible reduction about 400-500 mV more positive than the background reduction by the glassy carbon electrode, indicative of electrocatalytic hydrogen evolution. All the complexes exhibited similar catalytic waves which persisted after rinse tests signifying the generation of an electrode-adsorbed catalyst which was stable under catalytic conditions. A square planar Ni(II) complex, Ni(DPMDA) (DPMDA=2,2’-((diphenylmethylene)bis(1H-pyrrole-5,2-diyl))bis-(methaneylylidene))bis(azaneylylidene))dianiline), of the previously reported calixpyrrole ligand of was synthesized and analyzed for electrocatalytic hydrogen evolution in the presence of anilinium tetrafluoroborate. It was found that under catalytic conditions a heterogeneous species was formed on the electrode surface which was found to be stable and operate at turnover frequencies (TOF) of up to 25,900 s⁻¹ or 366,000 s⁻¹ cm⁻². Kinetic isotope effect (KIE) and Tafel analysis suggest rate-limiting proton coupled electron transfer (PCET) likely facilitated by the pendant amines which enabled high TOF despite evidence of redox-mediated outer-sphere electron transfer. Ni(DPMDA) was evaluated for electrocatalytic hydrogen evolution in the presence of a weaker proton donor, triethylammonium tetrafluoroborate. Under catalytic conditions, a heterogeneous species was similarly formed. Experimental evidence suggested that the identity of this species differed from that formed in the presence of anilinium as evidenced the absence of redox features attributable to the heterogeneous species, peak potential dependence on bulk catalyst concentration, and lower overpotential despite the use of a weaker proton donor. The lack of features attributable to the heterogeneous species indicated inner-sphere electron transfer and TOF of 5,700 s-1 or 80,000 s-1cm-2 were observed. Similarly, KIE and Tafel analysis suggest rate-limiting PCET for which the pendant groups were implicated as hydrogen bond acceptors/donors during buffered solution studies.Item Open Access An investigation of the application of autoencoders and large-language models to privacy-utility tradeoffs in group-specific settingsMandal, BishwasMachine learning models have emerged as highly effective tools in tackling an array of practical challenges, including image classification, regression tasks, behavioral forecasting, and natural language processing, among others. Their ability to analyze substantial volumes of data endows them with significant value across diverse domains. The widespread success of machine learning models has led data analysts and scientists to extensively incorporate them into predictive and generative modeling endeavors. While leveraging data can enable professionals to gain insights into user preferences and refine predictive and generative accuracy, there exists a risk of inadvertently or intentionally inferring sensitive personal information from the data. Consequently, there is a critical need for the development of privacy mechanisms capable of sanitizing data to shield sensitive attributes while retaining data utility. Achieving this balance is pivotal in safeguarding individual privacy amidst the complexities of the digital age. In discussions revolving around privacy considerations, there is a prevalent assumption that privacy requirements are homogeneous across the populace, a construct termed as the single-group setting. This dissertation introduces an adversarial learning framework that employs various iterations of autoencoders, specifically designed to navigate the privacy-utility tradeoff within this single-group setting. While the single-group setting holds significance in numerous practical contexts, it fails to consistently capture the varied requirements of different use cases. Recognizing the imperative to address a broader spectrum of scenarios, this dissertation introduces a problem formulation focused on the privacy-utility tradeoff within two distinct user groups. These heterogeneous groups encompass users characterized by differing private and utility attributes, aiming to encompass a wider array of application scenarios within the privacy-utility tradeoff domain. Furthermore, the landscape of computer science is undergoing significant transformation, particularly in light of the recent surge in large language models (LLMs). LLMs are rapidly evolving, necessitating a thorough examination of the impact of these advancements on privacy domain. Thus, this dissertation endeavors to investigate whether LLMs, endowed with diverse capabilities, can be effectively employed for data sanitization to uphold user privacy. The straightforwardness of this approach without requiring specialized expertise underscores the adaptability of large language models in addressing privacy concerns. Collectively, this dissertation seeks to enhance the understanding of privacy-utility tradeoff in different group specific settings with adversarial learning frameworks and large language models. The findings underscore the potential of these methodologies to provide robust privacy protections while simultaneously preserving or augmenting the utility of data across a myriad of applications.Item Embargo Yes, You Can, In Fact, Reuse Your Leeches Without the Fear of Nosocomial InfectionsSoula, MariajesusIntroduction: Leeches are used in human and veterinary medicine as a treatment for venous congestion. It is recommended to discard leeches after one use. A concern with reusing leeches is potential spread of bacterial infections. If a leech were to harbor bacteria from one patient in its gastrointestinal (GI) tract, it may transmit them to another patient, potentially, even serving as a vector for multidrug resistant (MDR) infection. We sought to determine the safety of reusing leeches inoculated with an MDR Staphylococcus aureus. Study design: Experimental, ex-vivo Animals: 63 leeches were split into eight treatment groups and one control group. Methods: Treatment leeches were fed canine blood inoculated with an MDR strain of Staphylococcus aureus while control leeches were fed clean canine blood. Cultures were obtained at 1 day, 1 week, and 1-, 2-, 3- and 4-months post-inoculation. At each time point, cultures were taken of aquarium water, GI contents, and blood that the leeches were allowed to feed on. Cultures were evaluated for the presence of Staphylococcus aureus. Results: All water samples were negative except for one tank at seven days. After two months and three months, all GI tracts and blood meal samples were negative, respectively. Clinical significance: Leeches will harbor MDR Staphylococcus aureus after inoculation with infected canine blood. This bacterium is not detectable in the water after 7 days and no longer detectable in the leech or blood meal after 3 months.Item Embargo Dietary and physical activity risk and protective factors for lean non-alcoholic fatty liver disease: A scoping reviewCorrigan, JoanneNon-Alcoholic Fatty Liver Disease (NAFLD) is one of the most common causes of chronic liver disease globally and describes a spectrum of conditions ranging from simple hepatic steatosis to liver cirrhosis and/or failure. Although it is more prevalent in populations with metabolic risk factors including obesity, insulin resistance, dyslipidemia, and type 2 diabetes, it can also occur in lean populations who may or may not present with symptoms of NAFLD. Consequently, lean populations with NAFLD can be overlooked in both clinical and research settings. Despite the associations between diet and physical activity and the prevention of many chronic diseases, primary research exploring the association between diet and physical activity and NAFLD risk in lean populations is lacking. The purpose of this scoping review was to describe the available research on dietary and physical activity risk and protective factors in lean NAFLD, define key terms related to this condition, and identify knowledge gaps to inform future research. A literature search was conducted between March 2021 and August 2023 in PubMed, Global Health, ProQuest Nursing and Allied Health, Web of Science, and Scopus. Sixty-four articles were included in the review. The predominant study designs were cross-sectional and prospective. More than half of the studies were based in Asia. Research topics included the associations between specific diets, food groups, macronutrients, micronutrients, beverages, and varying physical activity characteristics, and lean NAFLD risk. Very few definitive conclusions could be made about potential dietary or physical activity risk and protective factors for lean NAFLD due to several limitations in the current body of evidence. These limitations included a high risk for bias and lack of ethnic diversity in study populations, as well as significant heterogeneity in results, definitions of key terms, and NAFLD diagnostic criteria. To address these deficits, future research is needed on topics explored in the current body of evidence, using higher quality study designs that limit the risk of bias, integrate more ethnic diversity in study populations, and implement consistent terminology and NAFLD diagnostic criteria.Item Open Access Theatre skills for conflict management: Using theatre performance techniques to teach college students better conflict management abilitiesMorrow, CaleThe life of a traditional aged college student is filled with many fast-moving decisions and new life experiences. When conflict arises in a student’s life, it can upend a student’s progression if they are not properly trained to deal with conflict. Current conflict management teaching curricula being given to students are insufficient due to overly complex language and lack of emphasis on the social and emotional intelligence skills training required for successful conflict mitigation. To correct this problem, this dissertation proposed the creation of a new conflict management curriculum that combined traditional conflict management techniques with select theatre performance techniques to account for the inadequacies in current conflict management curricula. This new curriculum was tested through a workshop process with traditional college students attending a mid-sized, Midwestern research university acting as participants. All participants either worked for or lived in a building run by university housing services. Interviews with students were conducted post-workshop, and a qualitative, narrative based, case study was conducted to test this theatre infused curriculum. Justification for this new curriculum, detailed lesson plans for the workshop, a breakdown of the creation of the new curriculum, and the results of the case study can be found within.Item Open Access Investigating changes in scientists’ ethical decision making and course designsGarcia, TylerOne way to bring about change in higher education is to introduce professional development programs for higher education, however these programs have been found to be ineffective at promoting positive change for individuals and departments. To address the need for better programs, I worked on two projects: one project attempts to identify a way to improve Responsible Conduct of Research training and the other project is an assessment designed to be distributed in a Thermal and Statistical Physics course that supports instructors on improving their curriculum. Many scientists view science as value-free, despite the fact that both epistemic and non-epistemic values structure scientific inquiry. Current Responsible Conduct of Research training usually focuses on transmitting knowledge about high-level ethical concepts or rules and is widely regarded as ineffective. We argue that Responsible Conduct of Research training will be more effective at improving ethical decision making if it focuses on connecting values to science. Due to the investigation of research ethics education in physics being relatively new, we pull from philosophy and psychology to define ethical decision making using the Four Component Model. This model states that in order to make an ethical decision someone must consider four components: moral sensitivity, moral reasoning, moral motivation, and moral implementation. For this study we formed a moderated fellowship of fourteen science faculty from different disciplines who met for ten sessions over the course of a year, where they discussed the values embedded in different scientific norms. We then conducted interviews before and after the year-long fellowship that involved guided reflection of scenarios where there was some kind of ethical misconduct where the scientific practice required value judgements (e.g using unpublished data). From this data we looked at how the fellowship affected the scientists’ ability to recognize ethical dimensions in their work. We found that this fellowship improves moral sensitivity, but their moral reasoning does not change. We then identified a more precise approach to looking at scientists’ moral reasoning. This work can inform future ethical training to align better with what scientists value and introduce useful concepts from philosophy and psychology to education research in physics. There are calls to create assessments that focus on gathering evidence that shows both knowledge of the desired subject and transferable skills between disciplines while providing useful feedback to instructors. To answer this call, we created a thermal and statistical physics assessment that provides evidence of student knowledge and skills in a thermal or statistical physics course that also provides actionable feedback to instructors. To create tasks, we use a knowledge-in-use framework that focuses on identifying the evidence we need to see in student answers to claim students are able to do physics, not just know physics. These “evidence statements" are the observable features students generate that show they have knowledge to complete a claim. We need to determine a way to validate the tasks based on the focus towards obtaining evidence of student abilities when solving tasks. Current literature focuses on bringing in experts to validate whether the tasks are at the right level for the students. We are looking to expand on literature in Physics Education Research (PER) by articulating a way to validate tasks that use evidence-centered design through looking at students’ evidence statements. To validate the assessment, we identified new components to gather evidence towards validation. Using these new components we introduced a new methodology to validate assessments that focus on delivering feedback through evidence. We have conducted and analyzed student think-aloud interviews answering the tasks in a free-response format or in a Coupled Multiple-Response format. We also conducted faculty interviews to see if the tasks are relevant to their courses. Through these interviews we developed a new methodology of contributing to the validation of assessments that focus on faculty feedback. This dissertation introduces new methodologies for future researchers to improve on Responsible Conduct of Research trainings and assessment designed for supporting instructor curriculum. Through these new methodologies scientists can address the calls for better professional development programs in higher education.Item Open Access Grain Weight Retention during Terminal Heat Stress in Hard Winter WheatSchuh, NicholasClimate-resilient wheat cultivars with tolerance to high temperatures after flowering are essential to reliable wheat production in the central and southern Great Plains. Breeders have an experiential understanding of germplasm capable of maintaining test weight under terminal heat stress, yet understanding of underlying genetics is limited. In a preliminary greenhouse/growth chamber experiment to identify post-anthesis heat stress tolerance genetic resources within central and southern Great Planes germplasm, two breeding lines were identified with contrasting tolerance phenotypes: HV9W03-1596R maintained green leaf area, and TX04M410164 maintained grain weight under post-anthesis heat stress. A recombinant inbred population (208 lines) was developed from the progeny of crossing these two lines and grown in ten Kansas field environments. Traits measured were yield, plant height, flowering time, physiological maturity time, grain fill period, test weight, kernel diameter, kernel weight, and kernel hardness. Yield, plant height, flowering time, test weight, kernel diameter, and kernel weight were all found to be highly heritable. In the 2018 field season, average high temperature during the 21 days following anthesis at three trial locations was 29.1C to 30.4C, while the optimal temperature for wheat grain filling is reported to be 21.3C. In three 2018 trial locations, mean test weight ranged from 652 to 758 g L-1, and mean kernel weight ranged from 19.8 to 23.5 mg. In contrast, in three 2020 trial locations, mean test weight ranged from 745 to 830 g L 1, and mean kernel weight ranged from 26.5 to 30.9 mg. Stress sensitivity indices (SSIs) were calculated at seven trials, using three highest yielding trials as the control environment. The SSIs for flowering time and physiological maturity had very little variation under an extreme stress environment and high variation under a moderately stressful environment. We observed the same phenomena in yield and kernel diameter SSIs. Two quantitative trait loci were found on chromosome 1B in a preliminary analysis, and SNP markers were developed. One SNP was significant for kernel diameter, kernel hardness, kernel weight, test weight, grain yield, plant height, and grain fill period length and the other was significant for kernel hardness, test weight, grain yield, plant height, and grain fill period length best linear unbiased predictors. One SNP was significant for kernel diameter and test weight stress sensitivity, and the second SNP was significant for kernel weight, grain fill period, and physiological maturity stress sensitivity. The RIL population also was segregating for the Ppd-D1 and Vrn-D3 genes that affect flowering time. These flowering time genes had significant effects on stress sensitivity. Future work will isolate near isogenic lines from RILs heterozygous at one or both of the 1B regions. These lines will be evaluated for heat tolerance in controlled environments and field environments to quantify the effects of these regions on post anthesis heat stress tolerance.Item Open Access Non-exponential reward discounting in deep reinforcement learningAli, Raja FarrukhThe science of sequential decision making, formalized through reinforcement learning (RL), has driven various recent technological breakthroughs, from mastering complex games that require strategic thinking to driving advancements in natural language processing. Central to an RL agent's learning is how it treats rewards (the learning signal) and adjusts its policy to maximize cumulative rewards. Future rewards are weighed less than immediate rewards, and traditional RL methods employ exponential discounting to balance immediate and future rewards. However, studies from neuroscience and psychology have shown that exponential discounting does not accurately reflect human and animal behavior, who instead exhibit hyperbolic discounting of future rewards. This dissertation explores non-exponential discounting, such as hyperbolic, in different facets of deep RL such that it can mirror the intricate decision-making processes found in humans, and evaluate its impact on agent performance in a variety of settings. First, I revisit the idea of hyperbolic discounting and the auxiliary task of learning over multiple horizons in RL agents while using off-policy value-based methods, studying its impact on sample efficiency and generalization to new tasks while incorporating architectural and implementation improvements. Second, I introduce a two-parameter discounting model based on generalized hyperbolic discounting in the deep RL setting. With its sensitivity-to-delay parameter, this model enriches temporal decision-making in RL, as evaluated through empirical evidence. Third, I apply hyperbolic discounting to multi-agent systems, examining its influence on collective decision-making and performance, revealing the potential for improved cooperation among agents. These contributions highlight the impact of non-exponential discounting on agent performance, linking theory with AI practice, facilitating human-like decision-making, and paving the way for new research directions.Item Open Access An examination of legal representation on plea bargained sentencing outcomes for criminal defendants.Grube, JohnathanThis dissertation examines the pervasive notion that retained attorneys offer superior legal defense compared to appointed attorneys. Such beliefs hold substantial implications for justice equity, as a defendant's financial resources should not dictate the caliber of their defense or the subsequent sentence they receive. Yet, a dearth of understanding persists regarding the influence of attorney type on sentencing outcomes. This study bridges this gap through a quantitative examination of attorney type and its impact on sentencing. Indigent defendants, unable to bear the financial burden of legal representation, are informed by a judge of the attorney appointed to represent them in criminal proceedings. Judges appoint attorneys because these defendants may lack the means to retain an attorney with a proven track record of trial success, which financially able defendants can readily secure. Consequently, a defendant's limited resources may hinder appointed attorneys from mounting a robust defense, potentially affecting the decision to pursue trial. Therefore, it is crucial to ascertain whether indigent defendants receive equitable representation compared to those capable of retaining their own legal counsel. To address this concern, this dissertation employs bivariate logistic regression models to analyze the impact of defense attorney type on the plea negotiation process, as evidenced by negotiated sentencing outcomes, within Kansas state district courts. Specifically, utilizing sentencing data from the Kansas Sentencing Commission spanning fiscal years 2015 to 2019, this study applied logistic regression analysis to investigate the impact of attorney type across three distinct research questions pertaining to sentence disposition, departure sentences, and the choice between concurrent and consecutive sentences. Notably, all three models yield statistical significance and identified significant variables for each research question. Alongside numerous significant demographic variables, the analysis reveals attorney type as a significant predictor of both sentence disposition and departure sentences. The implications of these findings, alongside theoretical and policy considerations, are thoroughly discussed, aiming to inform future academic and policymaking endeavors.
