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Effects of Allocation Frequency on Cattle Performance and Forage Utilization when Swath Grazing a Sorghum-Sudangrass Hybrid in Eastern Nebraska
Get PDFSummary with Implications
A sorghum-sudangrass hybrid was swath grazed by growing steers (529 ± 18 lb) from November 2023 to January 2024. Treatments were offering new forage once (1X) or twice (2X) per week to determine the effect of allocation frequency on animal performance and forage utilization. Average daily gain was not impacted by treatment (1X = 0.45 ± 0.1 lb/day, 2X = 0.45 ± 0.1 lb/day). Pre-and post-graze biomass samples were collected to estimate forage utilization, which was not different between treatments (1X = 57.1 ± 3.6%, 2X = 61.1 ± 3.6%). However, there was a difference in carrying capacity with the more frequent allocations having greater carrying capacity compared to the less frequent allocation (6.8 vs 5.8 AUM/ac for 2X vs 1X, respectively). In other words, cattle allocated new forage 1X used more acres than 2X when grazed for the same number of days. For producers considering swath grazing as a winter-feeding strategy, the management practice of allocating new forage more frequently had the ability to increase the carrying capacity of the field by 17%. This is likely due to decreased trampling loss when cattle were allocated new forage more frequently
Understanding the Nexus Between Food Insecurity and School Readiness: A Comprehensive Analysis in Ghana
Get PDFThis study delves into the multifaceted challenges of food insecurity and its profound impact on school readiness among children in Ghana. Utilizing data from the Ghana Statistical Service and the Comprehensive Food Security and Vulnerability Analysis, and employing ArcGIS for spatial analysis, the research maps high food insecurity areas and overlays population density to prioritize interventions. Findings reveal a stark concentration of food insecurity in northern Ghana, worsened by adverse weather conditions, underscoring the urgency for targeted interventions. The study highlights how food insecurity extends beyond nutritional deficits, affecting socio-economic structures and family dynamics. Children in food-insecure households face significant cognitive, socio-emotional, and physical development hurdles, impeding their readiness for school. Nevertheless, resilience emerges as families tap into resourcefulness and social networks to bolster academic achievement. The research advocates for holistic approaches that address nutritional needs, emotional well-being, community support, and educational resources. Policy recommendations emphasize the importance of social safety nets, school feeding programs, and initiatives to enhance parental engagement and community involvement. In essence, this study bridges empirical evidence with practical implications, providing a roadmap for policy and program development. By understanding and addressing the challenges of food insecurity, strategies can be crafted to improve educational outcomes, foster holistic child development, and pave the way for a more equitable future for Ghana’s youth
Understanding the Context of Bullying: Examination of the Healthy Context Paradox and Peer Acceptance for Students with Disabilities
No full textThe purpose of this dissertation study was to examine how perceptions of school climate and social acceptance influence the relationship between bullying victimization and anxious and depressive symptoms for youth with and without disabilities. Students with disabilities are at increased risk for involvement in the bullying dynamic, both by bullying others and by experiencing victimization. Victims of bullying are more likely to experience peer rejection and greater internalizing problems, including higher levels of anxious and depressive symptoms. Research suggests that school-wide efforts to reduce bullying may leave some youth vulnerable to worse psychosocial outcomes, which has been called, “the healthy context paradox” (Salmivalli, 2018). Evidence for this healthy context paradox suggests that negative psychosocial outcomes associated with bullying victimization may be exacerbated, rather than mitigated, in healthier social contexts. This phenomenon has been examined among school-aged youth; however, it has not been tested among students with disabilities. Moreover, mechanisms underlying this phenomenon are still unclear. Data for the current dissertation study were collected from a larger research study examining correlates of bullying among youth referred to a cognitive-behavioral intervention for bullying involvement. Multigroup path analyses were utilized to test individual-level processes aligned with the healthy context paradox by examining perceptions of school climate as a moderator and perceived social acceptance as a mediator in the relationship between bullying victimization and anxious and depressive symptoms for students with and without disabilities. Moderated mediation analyses demonstrated that bullying victimization was associated with higher anxious and depressive symptoms through lower levels of perceived social acceptance when perceptions of school climate were low, but not when perceptions of school climate were high. Findings were consistent for students with disabilities and students without disabilities, underscoring the protective role of school climate in mitigating negative outcomes for youth who experience bullying victimization.
Advisor: Susan M. Sweare
Resilience of Interdependent Transportation and Healthcare Systems: A Simulation-driven Framework Incorporating Social Equity and Facility Optimization
No full textThe overarching goal of this dissertation is to develop an integrated, simulation-driven framework to assess and enhance the resilience of interdependent transportation and healthcare systems before, during, and after natural hazards. By examining how spatial disruptions, social vulnerability, operational constraints, and infrastructure interdependencies affect access to and functionality of hospitals, this research offers a multifaceted evaluation of system performance under stress. This dissertation examines the impact of natural hazards, particularly floods, on the interdependent transportation and healthcare systems. The proposed approach combines and advances GIS-based network analysis, graph-theoretical modeling, and discrete-event simulation to evaluate system performance under different scenarios. The goal is to provide practical solutions that support natural hazards preparedness, protect vulnerable communities, and reduce delays in emergency care.
Key findings show that flood-related transportation disruptions significantly reduced timely access to hospitals, especially for socially vulnerable populations. Simulations revealed that removing a single hospital due to flooding could double the number of census tracts experiencing hospital overcapacity, many of which are in already underserved communities. The research also found that targeted recovery strategies, focusing on restoring the most critical roads first, led to faster access restoration compared to uniform approaches. At the facility level, a hospital layout study using real patient flow data demonstrated that layouts optimized for surge conditions not only performed better during surges but also improved operational efficiency under normal conditions. Together, these findings offer a simulation-driven framework that can support more equitable, flexible, and resilient hazard planning. This work provides practical tools for transportation planners, healthcare facility designers, and emergency managers to better prepare for and respond to future disruptions, especially in communities with higher vulnerability.
Advisors: Lily Wang and Jennifer Lathe
How Developers Read and Use Source Code When Summarizing APIs
No full textThe study investigates how developers use source code to generate API summaries. Eyetracking data is analyzed from 30 participants performing summarization tasks. The source code (no comments) was their only information source. Participants’ summaries were evaluated for correctness and visual attention was mapped to specific code elements in the Eclipse IDE. Results show that developers who correctly summarized code spent significantly less time (half, on average) on the task. More experienced developers generally took longer, though not always resulting in a correct summary. Semantic similarity tools were used to assess whether correct participant summaries better reflected what they read, with Sentence-BERT showing moderate alignment but no statistically significant differences overall. These findings suggest that summarization accuracy is influenced more by reading strategy than experience and that current similarity models struggle to fully capture human summarization behavior. This work informs future improvements in developer tools and automated summarization systems
Evaluating Biodegradable Mulch as a Soil Conservation Tool and the Impact on Soil Properties and Yield in Soybean (\u3cem\u3eGlycine max\u3c/em\u3e) Cropping Systems in Eastern Nebraska
No full textThis study, conducted during the 2024 growing season, evaluated short-term effects of soil management practices on greenhouse gas (GHG) emissions, soil microclimate, nitrogen dynamics, weed suppression, and soybean (Glycine max) yield. In addition to conventional tillage and no-till, this research included cereal rye (Secale cereale) cover cropping and a novel sprayable biodegradable mulch (BioWRAP®) to assess emerging strategies for sustainable soybean systems under contrasting moisture regimes.
Field trials were established at two eastern Nebraska locations: Havelock (dryland, silty clay loam) and ENREEC (irrigated, clay loam). A strip-block randomized design with four replications tested six soil management systems: conventional tillage, no-till, fall-planted rye terminated at planting, spring-planted rye, late-terminated rye (V4 stage), and BioWRAP®.
Measured variables included cumulative CO₂ and N₂O fluxes, soil temperature and moisture (0–10 cm), weed density, nitrate (NO₃⁻) concentration, and yield.
At the Havelock site, no-till significantly reduced CO₂ emissions, and BioWRAP® lowered N₂O emissions relative to other treatments. At ENREEC, GHG emissions did not differ among treatments. Soil temperature and moisture varied over time but showed no consistent treatment effects.
Weed density was lowest under BioWRAP® and late-terminated rye, indicating effective suppression. BioWRAP® and no-till also resulted in higher nitrate levels at harvest, suggesting improved nitrogen retention.
Soybean yields did not differ significantly among treatments at either site, indicating that conservation-oriented practices can reduce environmental impacts without compromising productivity.
These results underscore the value of integrating conventional and novel management strategies—such as no-till, cover crops, and biodegradable mulches—to improve nitrogen use efficiency and suppress weeds in soybean production. While short-term environmental benefits were observed, further research is needed to evaluate long-term effects and scalability across diverse agroecosystems.
Advisor: Christopher Procto
Evaluation of Mechanical and Durability Properties of Concrete Incorporating CO\u3c/sub\u3e-treated Recycled Concrete Aggregates
No full textThe increasing demand for sustainable construction materials has heightened interest in using recycled concrete aggregates (RCA) as viable replacements for natural aggregates. However, RCA’s inherently higher porosity, elevated residual mortar content (RMC), and reduced mechanical properties have traditionally limited its use in structural and pavement concrete. This research systematically investigates improving RCA properties through CO2 carbonation treatment to enhance both mechanical and durability performance. Unlike prior studies that focused on limited sources or small-scale setups, this study evaluates RCA from four distinct infrastructure sources, including highway and airfield pavements, applying accelerated carbonation treatments at mid-scale and commercial-scale chambers under control conditions. The investigation involved detailed characterization of RCA before and after treatment, assessing specific gravity, water absorption, residual mortar content (RMC), aggregate crushing value (ACV), and freeze-thaw (FT) mass loss. Lab-scale carbonation was applied to seven RCA sources, while mid- and commercial-scale treatments were conducted on four selected sources. Concrete mixtures incorporating 25%, 50%, or 75% untreated and CO2-treated RCA were prepared and tested alongside a control mix meeting the Nebraska Department of Transportation (NDOT) 47B standard. Performance evaluations included fresh properties, compressive and flexural strengths, drying shrinkage, rapid chloride ion penetration, surface resistivity, and freeze-thaw durability. Results show that CO2 carbonation improved RCA quality by reducing water absorption, enhancing freeze-thaw resistance, and increasing ACV. The Concrete with treated RCA demonstrated superior durability, notably in freeze-thaw resistance, chloride ion penetration, and surface resistivity, achieving or surpassing NDOT performance benchmarks. Treated RCA not only improved durability but also enabled the use of higher RCA replacement percentages in concrete, meeting all performance requirements. Field validation on pavement sections at Lincoln West A Street and the 60th Street Approach Road confirmed laboratory findings, with CO2-treated RCA concrete delivering mechanical strength and durability comparable to conventional natural aggregate pavements. By demonstrating the scalability of carbonation treatments from lab to industrial levels and validating performance in field applications, this research positions CO2-treated RCA as a sustainable, durable, and scalable material for resilient pavement construction, supporting its broader adoption in sustainable infrastructure development.
Advisor: Jiong H
Nebraska Balanced Mix Design - Phase II
No full textThis study aimed to propose a performance-based framework to evaluate highly recycled asphalt mixtures containing polymer-modified binders for potential use in a balanced mix design (BMD) specification in the state of Nebraska. For that, loose and compacted mixtures were directly collected from plant and field projects within a benchmarking study, subjected to an extensive experimental program. The laboratory investigation employed different monotonic tests recommended in BMD Phase 1, as well as the dynamic modulus test. Three long-term aging protocols were investigated in terms of their impact on the mechanical, rheological, and chemical characteristics of asphalt mixtures and binders. Moreover, field assessments with cores and pavement management system data were added to the analysis. Results evaluated the sensitivity and significance of various tests for characterizing rutting and cracking resistance across mixtures varying in binder sources, grades, recycled contents, and warm mix additives. The variability and discrimination potential of performance-based parameters were identified, and suitable performance tests were suggested for the BMD framework considering the type of mixtures and site conditions of this study. The preliminary threshold criteria for each performance test were selected using a mechanistic-empirical approach considering three representative structural layers. Regarding the aging protocol, while the studied aging protocols yielded similar cracking resistance trends, their aging severity differed. Considering mechanical, chemical, and rheological similarities, an adjusted long-term aging protocol was selected for the potential implementation in the state’s BMD framework. Reheating and dwelling time impacted performance indices, showing they could be considered in criteria selection. The selected performance-based parameters and threshold criteria corroborated with the results from field rutting, roughness, and cracking assessments, which further verify the outcomes. It was recommended to validate the selected performance tests, associated preliminary criteria, and aging protocol using more extended field data collection
Bovine Milk Extracellular Vesicles Prepared by Ultracentrifugation Contain Microbial mRNAs That Do Not Accumulate in Human Plasma Following Milk Consumption
No full textAim: Small extracellular vesicles (sEVs) and their RNA cargo are not exclusively derived from endogenous synthesis but can also be absorbed from milk and gut bacteria. Given the high rate of bacterial fermentation in the gastrointestinal tract of ruminants, we hypothesized that preparations of bovine milk sEVs (BMEs) contain bacterial mRNAs whose bioavailability in humans remains unknown. Methods: BMEs were purified from chilled antibiotics-treated raw milk (RM) and store-bought skim milk (SBM) using sequential ultracentrifugation. BMEs from RM were treated with RNase to remove RNA adsorbed to the BME surface. BMEs from SBM were treated (SBM+) or not treated (SBM–) with RNase. mRNAs were identified by RNA sequencing analysis and mapping to the bovine genome and bacterial reference. The bioavailability of bacterial mRNA was assessed by RNA sequencing analysis of plasma collected before and 4 h after consuming one liter of cow’s milk in humans. Results: Approximately 50% of the mRNA sequencing reads were non-bovine in BMEs from RM, SBM+, and BM–. Up to two-thirds of the non-bovine contigs mapped to microbial transcriptomes, including bacteria, viruses, and fungi. The levels of 17 bacterial mRNAs from Escherichia coli and Cutibacterium acnes were significantly higher after milk consumption compared to before milk consumption, but the number of reads was too low to confidently draw the conclusion that microbial mRNAs in milk are bioavailable in humans. Conclusions: BMEs prepared by ultracentrifugation contain bacterial mRNAs that are not bioavailable in humans
Exploring Identity through Six-Panel Memoirs with Collegiate and Secondary Students
No full textMemoir writing helps to provide mirrors and windows (Bishop, 1990) into the larger human experience by conveying narratives that center on actual life experiences. While memoirs are a well-established genre in literature and literary criticism (Aronowicz, 2024; Kleinbauer, 2007), only recently have graphic novels, including graphic novel memoirs, gained popularity and respect not only among teens, librarians and educators but also among the public (Williams, 2022). In this article, we describe a six-panel memoir assignment completed by collegiate and secondary students and analyze a sampling of memoir creations by both groups of students. Specifically, we are interested in the expressions and representations of identity the students created, including semiotics, mediums, the texts that shaped their lives (Kist, 2017) and the words they selected for their narratives. We conclude with recommendations for the mini-graphic novel memoir creation that can provide support for both critical reflection and graphic novel memoir writing development