Electronic Theses and Dissertations

Permanent URI for this collection


Recent Submissions

Now showing 1 - 20 of 385
  • Item
    (August 2023) Zavala, Maria Louisa; Ghosh, Nabarun; Crosman, Erik T.; Rogers, William J.; Pjesky, Rex
    ABSTRACT Atrazine, a Restricted Use Pesticide classified by the EPA, is known to contaminate surface water and groundwater, primarily through agricultural runoff. Elevated levels of atrazine beyond EPA drinking water standards have raised concerns about human health impacts. Atrazine has been linked to adverse reproductive effects in wildlife and amphibians, with water contamination being a significant contributor. Studies have shown that Atrazine is linked to the decline of amphibians and other species. It is a known endocrine disruptor that affects sexual development in amphibians by changing the hormone cycle. Furthermore, ongoing research is exploring its potential as an endocrine disruptor and carcinogen. Despite the risks, atrazine remains popular in agriculture due to its effectiveness in controlling broadleaf and grassy weeds. So why is it used in agriculture so regularly? The mechanism of action is that atrazine disrupts photosynthesis in most broadleaf plants and grasses. Once applied it is taken up by the root system and the leaves moving upward in the plant areas of new growth making the plant dry out and die. While it is very effective in killing weed systems in 14-21 days, atrazine is shown to stay in the soil system for approximately 6 weeks after only one application. In those 6 weeks, many things can occur that can distribute the herbicide into many other locations which can in turn get into human systems. For instance, one of the top concerns is soil runoff getting into human water systems after excessive agricultural watering or even in a natural event of a rainstorm. Another instance would be the aerial application of the herbicide being distributed by the wind to another location the chemical was not initially intended for due iii to wind dispersion. The wind carries contaminants away from their intended source a problem in dry windy rural areas. Another factor that affects this herbicide would be volatilization which can also escape into our atmosphere. All the above factors are important arguments that need to be researched further as a circumstance that can cause human health issues with the distribution and use of atrazine leading to possible human exposure. To investigate its effects on community health, this study focused on two main areas, with particular emphasis on using the standard plant test system, Allium cepa. In the experiment, Allium cepa bulbs were subjected to various concentrations of the herbicide in chemical treatments. Allium cepa, commonly known as green onion, serves as a widely used “test system” for evaluating the impact of different mutagens on organisms globally. This versatile plant species is utilized as a model organism in chemical screening processes and in situ assessments to determine the genotoxicity of environmental contaminants. A.cepa offers several advantageous characteristics for cytological studies, making it an ideal test system. When cultivated hydroponically, it exhibits prolific root growth. The plant's chromosomes are large, well-defined, and present in a limited number (2n=16), allowing for easy analysis from metaphase plates. The second test system used for experimentation was the Daphnia magna. Daphnia as an indicator of environmental pollutants’ sensitivity. Daphnids reflect a high sensitivity to environmental pollutants because they are sensitive to toxicants and indicate water pollution. Daphnids demonstrate reproductive decline, aberrant vertical mobility, and phenoplasticity to name a few when exposed to environmental stressors. Abiotic and biotic stressors include chemical substances, synthetic hormones, acidity, salinity, etc. I iv tested the survival rate of Daphnia at different concentrations of the herbicide and recorded the concentration for the LD50 (Lethal Dose 50). I found that Daphnia exhibited lethality even with the very lowest experimented dose of the herbicide proving thereby the herbicide subjected to this experiment is both genotoxic and lethal to the daphnid and other organisms.
  • Item
    The Effect of a Direct-Fed Microbial on Salmonella Prevalence and Concentration in Feedlot Steers and Assessing Differences in Salmonella Carriage Between Dairy-Beef and Native Cattle
    (August 2023) Thompson-Smith, Aubrey Catherine 1995-; Lawrence, Ty E.; Tennant, Travis C.; Lucherk, Loni
    Multiple studies were conducted to evaluate differences in Salmonella prevalence and concentration in feedlot cattle within the Texas Panhandle. The first study evaluated the efficacy of a direct-fed microbial upon feedlot performance, carcass characteristics, and Salmonella prevalence in subiliac lymph nodes (SLN). Yearling crossbred beef steers (n= 6400; initial body weight (BW) 358 kg) were used to investigate the efficacy of a direct-fed microbial upon animal growth performance, carcass characteristics, and prevalence of Salmonella in SLNs after a feeding duration of 182 days. Steers were allocated to 1 of 32 pens (n=200/pen) within 16 blocks, and assigned to 1 of 2 dietary treatments; no probiotic (CON) or 2 g/steer/d of Lactobacillus acidophilus, Enterococcus faecium, Pediococcus pentosaceus, Lactobacillus brevis and Lactobacillus plantarum providing a total of 1 billion CFU (Life Products, Inc., Norfolk, NE; 10-G). At harvest, SLNs were randomly obtained from 40 animals per pen for blocks 1 through 10. Data were analyzed as a randomized complete block design and pen served as the experimental unit. No differences (P ≥ 0.26) were observed between treatments for dry matter intake, final BW, average daily gain, or feed efficiency. When evaluating carcass characteristics, there were no differences (P ≥ 0.15) for hot carcass weight or liver abscess prevalence. However, dressed carcass yield tended to differ (P = 0.07) between treatments (CON - 64.51%, 10-G - 64.34%). No differences (P ≥ 0.12) were observed for marbling score, ribeye area, backfat thickness, or USDA quality grade outcomes. Lower frequency (P = 0.03; CON - 37.95%, 10-G - 25.45%) of Salmonella positive subiliac lymph nodes was observed for cattle supplemented dietary 10-G, whereas log concentration of Salmonella did not differ (P = 0.31) between treatments (CON - 1.62 CFU/ln, 10-G - 1.32 CFU/ln). In conclusion, the supplementation of 10-G direct fed microbial did not influence live or carcass performance within this trial however prevalence of Salmonella positive subiliac lymph nodes was reduced. Fecal grabs and subiliac lymph nodes (SLN) were sampled from carcasses representing pens of beef (n = 25) and dairy-beef crossbred cattle (n = 25) within each of 10 different feedlots to investigate the prevalence and concentration of Salmonella at harvest, during the months of August, September, and October. Both beef and dairy-beef crosses were fed at the same feedlot within the Texas Panhandle, were harvested on the same day, and had longitudinal fecal and SLN samples collected. Immediately following exsanguination, via rectal palpation, fecal samples were collected, and immediately prior to chilling, SLN were obtained from 25 animals of each breed type, from each feedlot. Data were analyzed using a mixed model analysis, with breed type as a fixed effect and feedlot as a random variable. Differences (P < 0.01) were observed between cattle types for Salmonella prevalence within fecal samples at harvest. However, no differences (P ≥ 0.50) were observed for Salmonella prevalence within SLN or concentration within either fecal samples or SLN. When evaluating Salmonella outcomes by feedlot, differences (P ≤ 0.01) were observed for Salmonella prevalence and concentration within fecal samples, and Salmonella prevalence within SLNs. Salmonella prevalence within fecal samples ranged from 0 to 96% and concentration ranged from 0.00 to 6.28 CFU/g. Within subiliac lymph nodes, Salmonella prevalence ranged from 0.00 to 62.91% between feedlot locations. No differences (P = 0.47) were observed between feedlots for Salmonella concentration within SLN. In addition to the samples collected at harvest, fecal pat samples were collected from newly received cattle pens (n = 5 pens of beef; n = 5 pens of dairy-beef crosses) from 9 different feedlots in the Texas panhandle during a 5-week period between June and July 2023. No differences (P ≥ 0.22) in Salmonella prevalence or concentration were observed within fecal samples by breed type or by feedlot location. In conclusion, the only difference that appears to exist between native and dairy-beef cross animals is that of Salmonella prevalence, at harvest within fecal samples. In addition, stark differences exist for Salmonella prevalence and concentration across feedlots in samples collected at harvest. These outcomes suggest research should focus on reasons for variability in feedlot Salmonella rates in finishing cattle.
  • Item
    Ground-level ice nucleating particle abundance on the North Slope of Alaska during Fall-Winter 2021
    (August 2023) Simonsen, Stephanie R; Hiranuma, Naruki; Rogers, William J.; Bithi, Swastika; Bhattacharia, Sanjoy; Ottmar Möhler
    Atmospheric ice-nucleating particles (INPs) are an important subset of aerosol particles that promote the heterogeneous formation of ice crystals under ice supersaturated conditions. In the Arctic, INPs contribute to partitioning between ice and liquid water in mixed-phase clouds, influencing their albedo and climate forcing. Furthermore, because INPs can catalyze precipitation and function as cloud-destroying agents, the increase in INPs may result in accelerated positive radiative feedback. However, the abundance and source of Arctic INPs are not yet well understood. This study examined how profound atmospheric dynamics and extreme meteorological conditions coinciding with low-pressure systems introduce INP anomalies on the North Slope of Alaska (NSA). A Portable Ice Nucleation Experiment (PINE) chamber, which simulates adiabatic expansion cooling, was used to monitor, and measure INP abundance with ≈12-min time resolution at Barrow Atmospheric Baseline Observatory (71.32° N, 156.61° W). The INP abundance is reported as a function of freezing temperature between the approximate -15 °C and -30 °C range and collected in November-December 2021. The offline measurements of the same period are found using the West Texas Cryogenic Refrigerator Applied to Freezing Test (WT-CRAFT) at temperatures between 0 °C and -25 °C. Measured INP concentrations at overlapping temperatures of both instruments are then compared. Besides the discussion of general INP abundance in the NSA region, the influence of atmospheric low-pressure systems, as well as geopotential iii height anomalies, on the ground-based INP abundance (averaged for 6-hour) is discussed in this work. The influence of heating on multi-seasonal INP abundance is also discussed. A potential linkage was observed between INP concentration and the newly developed climate index Aleutian Low Beaufort Sea Anticyclone (ALBSA). Finally, the current international protocols for ambient aerosols, as well as further need in the international legitimate framework for the aerosol-cloud-climate interactions, are investigated and discussed.
  • Item
    Influence of Fire Seasonality on Insect Pollinators in a Sand sage ecosystem
    (August 2023) Rhodes, James Zachary 1991-; Johnson, James B.; Sissom, David; Crosman, Erik T.
    Pollinators are essential for seed production in natural and agricultural environments, but recent research indicates that their populations are declining. The observed decrease in pollinator population can be attributed to various factors such as habitat loss and fragmentation, disease, and pesticides. These declines have led land managers to explore ways to enhance pollinator habitats. The use of prescribed fire is one crucial tool for managing the landscape in the Rolling Plains of Texas. This study focuses on understanding how the seasonality of fires affects insect pollinators in the sand-sage prairie ecosystem at the Matador Wildlife Management Area in Cottle County, Texas. The Matador Wildlife Management Area 273-hectare “Headquarters Pasture” is the focus of this study. The pasture is divided into fifteen plots, each of which is subject to variations in prescribed burn treatment. Five plots are burned in winter, some are burned in the summer, while others remain unburned year-round. To assess the number of insect pollinators in each burn regime, malaise traps were set up at the center of every plot for two weeks, starting from the second week of May and July in 2021 and 2022. The samples were collected during the same period for both years. A total of 20,815 insects were collected in the malaise traps over eight weeks. Using R, a multivariate abundance model and Simpson's Diversity index were used to measure biodiversity and abundance across treatments, sampling seasons, and years. The multivariate abundance model indicated that the influence of burn treatment was not statistically significant. Abundance varied significantly between years and seasons for particular orders, likely due to weather patterns during the sampling periods. The diversity analysis using the Inverse Simpson's Diversity index did not show significant differences based on the burn treatment. However, there was a significant diversity difference for some orders based on the year, possibly due to weather conditions. The study's findings do not currently warrant any management recommendations. Future studies with higher resolution, more differentially burned plots, over more time, or to a finer taxonomic scale will be necessary to determine the impact of fire seasonality on insect pollinators in a sand sage ecosystem.
  • Item
    A Two-Dimensional Finite Element Model for Surface Flow Characteristics of the Chequamegon Bay, Lake Superior
    (August 2023) Jensen, Jana; Howell, Nathan; Lockwood, Pamela R.; Fisseha Alemayehu
    The Chequamegon Bay, a shallow bay on the south shore of Lake Superior, was modeled using 2D shallow water equations in FreeFEM++ with the finite element method to study the surface flow under varying boundary conditions and compare it to previously collected data. The approach did capture the velocity flow of the Bay about 63% of the time and 66% of the time for the direction of the flow. An understanding of how long it takes water in the Bay to exchange with rest of Lake Superior is essential for understanding the continued risk for water quality of the Chequamegon Bay. The surface flow was created by changing boundary conditions every 6 hours using data from a USGS buoy. Pollutants were added to the Bay in different locations. Pollutants stayed in the Bay for 40 to 66 days with the pollutants first reaching the outlet to Lake Superior between 16-22 days depending on where the source of the pollutant was located. Using FreeFEM++ the surface flow of the Chequamegon Bay was modeled using and further research can be done to further understand the deeper circulation of the Bay. FreeFEM++ has numerous examples for simulating 2D models and is developing finite volume methos as well. FreeFEM++ has shown to work well in this situation, modeling surface flow and studying residence time.
  • Item
    Grain Sorghum Production Analysis in U.S. under Declining Ogallala Aquifer, U.S.-China Grain Sorghum Trade, and Food Security Issues in Bangladesh
    (August 2023) Islam, Tania; Almas, Lal K.; Almas, Lal K.; Guerrero, Bridget; Marcillo, Guillermo; Arnold, Chelsea
    This master’s thesis investigates production patterns of grain sorghum in the United States, sorghum trade with China, and the interconnected aspects of food security in Bangladesh through three comprehensive essays. The first essay concentrates on sorghum production trends in Texas, emphasizing the adaptability and advantages of this cereal crop in regions grappling with environmental challenges. This research analyzes temporal changes in harvested acres, production, and yield patterns by utilizing state-level agricultural survey data from 1975 to 2018 and employing exponential growth and quadratic regression models. In addition, the Cobb-Douglas production function was used for identifying significant factors affecting the production. The study uncovers a consistent downward trajectory in harvested acres, and production quantity. However, it also highlights the potential for improvement by promoting the use of advanced sorghum varieties to bolster future production. The major factors influencing grain sorghum production are identified as harvested area, yield, and domestic consumption. The study indicates that providing financial support and encouraging farmers to adopt modern agricultural technologies will enhance grain sorghum productivity and sustainability. The second essay delves into the intricacies of sorghum trade between the United States and China. Sorghum, an ancient grain primarily used for livestock feed, holds considerable significance in the agricultural sector of the United States. Through a comprehensive analysis, this research investigates the determinants of sorghum import demand in China from the United States. Factors such as the sorghum-corn price ratio, exchange rate, per capita gross national product (GNP), and livestock production are considered. Taking annual time series data spanning from 1991 to 2020 and utilizing the single equation import demand model, the study identifies the influential role of these factors in shaping China’s sorghum import quantity. Moreover, it presents a forecast indicating a declining trend in Chinese sorghum imports from 2021 to 2030. The research results indicate that sorghum-corn price ratio, exchange rate, and per capita gross national product are significant factors which affect grain sorghum import quantity to China from the United States. The third essay addresses the urgent issue of food insecurity in Bangladesh, exploring the relationship between food insecurity, economic growth, education, environmental risks, and rice production. By utilizing annual data from 2001 to 2019 and employing an autoregressive distributed lag (ARDL) model, this study establishes a positive relationship between food insecurity and CO2 emissions. Furthermore, it demonstrates that government investment in education improves the lower-class income and lessens the extremity of food insecurity. However, rice production exhibits a negative association with food insecurity in the long run. To tackle this challenge effectively, the study proposes the implementation of favorable policies such as climate-smart agriculture practices, including conservation agriculture, improved water management, and the use of drought-tolerant or flood-resistant rice varieties. An early warning about weather-related risks will help the farmers. By connecting these three essays, this thesis sheds light on the multifaceted nature of sorghum production patterns, sorghum trade dynamics, and global food security. The study emphasizes the importance of favorable import policies for U.S. sorghum in the Chinese market. Additionally, the findings underscore the necessity of implementing socioeconomic and environmentally favorable policies to effectively address food insecurity in Bangladesh. These insights provide a comprehensive foundation for further research and policy development, aiming to foster sustainable and secure food systems on a global scale.
  • Item
    (August 2023) Hamilton, Aaron; Drumheller, Kristina; Drumheller, Kristina; Brooks, Mary E.; Kinsky, Emily
    Situational crisis communication theory, developed by Coombs (2007), was used to evaluate and code communication used by higher educational institutions in the Texas Panhandle during December 2019 through December 2020. This time period was determined relevant because the COVID-19 pandemic closed institutions down, and impacted fall 2020 enrollment (Centers for Disease Control and Prevention, 2022). Communication posted by the institutions across Instagram, Facebook, Twitter, and COVID-19 webpages was collected and coded. Communication was coded with a rubric that evaluated calls-to-action, crisis response types, and institutional responses. Calls-to-action were related to public health, admissions, enrollment, information relevant to the institutions. Crisis response types were deny, diminish, and rebuild based upon research by Liu et al. (2018). Institutional responses were guidance (connected to calls-to-action), informative, and neutral. The amount of communication institutions published was weighted against enrollment and admissions data. One finding is institutions of a larger size had more defined communication patterns than smaller institutions. The institutions in the study did not experience a secondary crisis that would warrant deny or diminish response. More beneficial communication an institution used could have a possible impact in retaining stakeholders. Ultimately institutions in the Panhandle may have used communication that would allow them to retain stakeholders during the crisis.
  • Item
    (May 2023) Devadoss, Timothy Pramod; Bithi, Swastika; Hiranuma, Naruki; Bhattacharia, Sanjoy
    Atmospheric ice-nucleating particles (INPs) promote the formation of ice particles in clouds. They usually modulate the properties of clouds, precipitation, and climate. The effect of INPs is predominant in low Arctic mixed-phase clouds. However, ambient ice nucleation in clouds is a complex process encompassing multiple freezing mechanisms. Limited knowledge about nature and the role of high-latitude INPs in the climate system is available. To fill the knowledge gap, this thesis project developed the West Texas A&M University Microfluidic Static Droplet Array (WT-MFSDA) platform for studying atmospheric ice nucleation, specifically immersion freezing. WT-MFSDA combines a microfluidic device containing interconnected droplet parking traps, a unique method of hand pipetting to create an array of INP-laden nanoliter-sized droplets, and a commercialized cooling unit for visualization and characterization of freezing events of hundreds of individual droplets. Each droplet is geometrically separated from each other and enveloped with a thin film of mineral oil. This spatial arrangement increases the reliability and reproducibility of the measurement by eliminating the artifacts due to surface contact, mass transfer, and/or evaporation. This platform is useful to simulate and investigate the immersion freezing of water and/or any INP-involved suspension down to the homogenous freezing temperature (below -35 °C) at a wide range of cooling rates from 0.01 to 30 ℃ per minute, which corresponds to atmospherically relevant cloud updraft velocities. A systematic uncertainty in terms of temperature is ± 0.3 °C. The device performance is verified with the known composition of bulk powder INP surrogates, such as illite NX, Snomax®, and microcrystalline cellulose. The results from nL-freezing assays of WT-MFSDA were compared and verified to/against the results of published immersion freezing results. The WT-MFSDA immersion freezing platform shows the potential as an affordable and handy tool for studying ice nucleation in clouds.
  • Item
    (August 2023) DeLeon, Lyanna; Ghosh, Nabarun; Crosman, Erik T.; Ghosh, Debajyoti; Ghosh, Nabarun; Pjesky, Rex
    Fungi can grow in both indoor and outdoor environments and may enter a house through open doorways, windows, vents, as well as heating and air conditioning systems. I have used two different techniques to capture and collect fungal samples. I used a Burkard Volumetric Spore Trap to capture the aeroallergens. It was placed on the third-floor roof of the Natural Science Building of West Texas A&M University. I collected the spores on the Sellotape placed on the drum and stained them with 2% safranin and mounted the slide in Gelvatol. I observed the prepared slides using BX-40 Olympus Microscope equipped with a DP-74 digital camera and the CellSens software. I observed the frequent presence of fungal spores like Alternaria alternata, Stachybotrys, Drechslera and ascospores. I also observed plenty of burnt residues, gums and resinous exudates from the plants and various forms of fibers. All these are considered as potential allergens and causal factors for allergic rhinitis and related symptoms. In the second part, I collected spoiled food materials and cheese. I stained the isolated fungal materials after a brief flaming on an alcohol lamp. After staining with Lacto-phenol Cotton Blue stain, I observed the spores and mycelia produced by the fungi using a Leica DM-750 digital microscope equipped with LAS V4.9 software for capturing images. Micrographs were captured, analyzed, and labeled accordingly. I observed Rhizopus stolonifer, Colletotrichum truncatum, Aspergillus niger, Penicillium notatum and several types of spores from Ascomyceteous fungi. Our continued research will include collection of fungal samples from different households, capturing iii images after staining suitably and analyzing them based on their spore morphology using the standard identification keys.
  • Item
    Antimicrobial Effectiveness of a Copper Surface Patch
    (August 2023) Cervantes, Keshon William Ladale 05/04/1997-; Bouma, Carolyn; Bouma, Carolyn; Karaganis, Stephen; Mukherjee, Maitreyee
    Microbial resistance to traditional antibiotics and household cleaning chemicals is an increasing problem in today’s climate. The world was recently in a global pandemic, and alternative techniques and products that can kill microbial organisms are now in high demand. One new product is Copper Clean™, an EPA approved antimicrobial surface patch intended for use on high-contact surfaces. Copper Clean’s™ alloy is a patent-pending technology that contains >90% Copper by weight, produced by Buffalo Technology Group. Our objective was to test Copper Clean’s™ ability to kill representative organisms from the human microbiome and environment using a time-kill assay. Seven organisms were used, including Gram-positive (Staphylococcus epidermidis, Streptococcus mutans, Methicillin-Resistant Staphylococcus aureus, and Bacillus megaterium) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and Salmonella enterica). We observed a ≥5-log reduction of Staphylococcus epidermidis, Methicillin-Resistant Staphylococcus aureus, Streptococcus mutans, and Escherichia coli after 2-3 hours of contact with Copper Clean™ in an aqueous environment when compared to our control. Our results demonstrate the effectiveness of Copper Clean™ against representative environmental and human microbiome organisms.
  • Item
    (August 2023) Belt, Kara Lynne Mease; Lawrence, Ty E.; Lucherk, Loni; Tennant, Travis C.; Perkins, Tommy
    The objective of this study was to compare live and carcass grading outcomes of dairy cross progeny from a sire derived via carcass cloning to progeny from a competitive traditional purebred Angus sire. Semen was artificially inseminated into Jersey cows from an F1 sire (AxG1) derived from USDA Prime Yield Grade One carcass clones and a high-performance purebred Angus sire (Foundation). Calves were born at the dairy, raised in hutches on the dairy, and grown in a separate facility - all in the Texas panhandle. Cattle were later transported to Nebraska for finishing. Both steers and heifers were harvested at a commercial beef processor in Colorado and vision camera grading data was collected to assess carcass quality and yield outcomes. Continuous data were analyzed using the MIXED procedure; frequency data were analyzed using the GLIMMIX procedure. The fixed effect was sire and the random effect was harvest date. Additionally, least squares means were calculated using the LSMEANS option, and mean separation was completed using the PDIFF option. Treatment comparisons were tested for significance at α = 0.05. In live growth, calves sired by Foundation were heavier (P < 0.01) both when they entered (396.1 vs 383.0 kg) and exited (590.1 vs 568.8 kg) the Nebraska feedyard. Similarly, calves sired by Foundation had heavier (P < 0.01) hot carcass weights than AxG1 (374.9 vs 361.4 kg). No difference (P = 0.27) was detected between sires for longissimus muscle area (96.6 vs 95.7 cm2) or marbling score (Moderate26 vs Moderate20). Moreover, AxG1 sired calves had greater (P < 0.01) longissimus muscle area per unit of carcass weight (26.7 vs 25.9 cm2/100kg). Calves sired by AxG1 were leaner (P < 0.01) than those sired by Foundation as evidenced by less 12th rib subcutaneous fat (1.11 vs 1.26 cm) coupled with lower calculated yield grades (2.37 vs 2.59). Moreover, calculated empty body fat was greater (P < 0.01) for Foundation sired carcasses than those sired by AxG1 (29.9 vs 28.9 %). Total carcass value differed (P < 0.01) with Foundation sired calves having the highest valued carcass, compared to calves sired by AxG1. Foundation sired calves were represented by a greater (P < 0.04) percentage of USDA Prime carcasses (26.32 vs 17.79 %) whereas AxG1 sired calves had a greater (P < 0.05) percentage of USDA Choice carcasses (77.74 vs 69.48 %). AxG1 sired calves were represented by a greater (P = 0.04) percentage of Yield Grade 1 carcasses (27.48 vs 19.25 %). No difference in frequency of Yield Grade 2 (55.40 vs 57.95 %) or 4 (1.41 vs 1.0 %) carcasses was observed between sires. Frequency of Yield Grade 3 carcasses was greater (P < 0.01) for Foundation compared to AxG1 (23.94 vs 13.58 %). Carcass outcomes suggest that progeny sired by Foundation were of slightly greater mass whereas progeny sired by AxG1 were of slightly higher yield. Our objective was to evaluate the sensory traits of beef steaks originating from two muscles packaged via two methods and subjected to four freezing durations. Paired strip loins (USDA IMPS #180) and top sirloin butts (USDA IMPS #184) from USDA Choice carcasses (n = 15) were cut into 2.54-cm-thick steaks represented by the M. longissimus lumborum (LL) and M. gluteus medius (GM). Individually vacuum packaged steaks were transported from Canyon, TX to Fayetteville, AR, and re-packaged according to randomly assigned treatment: vacuum (VAC) or overwrap (OW) packaging. After 3d of continuous exposure to light emitting diode retail display, steaks were separated by storage treatment: 6d fresh; 1-week, 1-month, 6-month, and 9-month frozen (-20°C). After each storage duration was completed, steaks were transported back to Canyon, TX for trained sensory panels (n = 75). During each panel, four steaks (VAC LL, VAC GM, OW LL and OW GM) were cooked to 71°C using clamshell grills, then cut into steak thickness x 1-cm cubes. Panelists evaluated samples for beef flavor identity, brown/roasted, bloody/serumy, fat-like, umami, overall tenderness, overall juiciness, and off flavors (bitter, cardboard, fishy, liver-like, oxidized, rancid, refrigerator/stale, and sour). Statistical analyses were conducted using the procedures of SAS. Least squares means were calculated using the LSMEANS option, and mean separation was completed using the PDIFF option with the Bonferroni option. Treatment comparisons were tested for significance using PROC GLIMMIX with α = 0.050. Fixed effects were muscle, package type, and duration, and the random effect was panel, ordered served within the sensory panel, and peak temperature. Muscle by storage duration interaction was observed for beef flavor identity, oxidized and sour (P ≤ 0.039). Trained panelists did not detect differences in beef flavor for LL across duration, however GM steaks had lower ratings at 6 and 9 months frozen. Panelists rated GM greater (P = 0.039) than LL for oxidized and sour flavors after 9 months frozen storage. The interaction (P = 0.024) between packaging type and muscle indicated OW GM was rated lower for juiciness than all other muscle/packaging types. An interaction was observed between package type and cold storage duration for beef flavor identity, oxidized, refrigerator-stale and sour flavors (P ≤ 0.009). Steaks VAC packaged had higher beef flavor ratings at 9 months frozen storage, whereas beef flavor of OW packaged steaks decreased (P = 0.009) as duration increased. Steaks in OW packaging increased (P ≤ 0.004) in oxidized, refrigerator/stale, and sour flavor ratings as storage duration increased. Steaks VAC packaged were rated more sour (P = 0.004) at 6 and 9 months frozen storage than OW. Brown roasted and fishy off-flavor ratings were higher (P ≤ 0.002) for OW steaks than VAC steaks. Bloody serumy, umami flavors, and tenderness outcomes were rated higher (P ≤ 0.006) for VAC steaks than OW steaks. Fat-like, umami flavors, and tenderness were rated higher (P < 0.001) for LL steaks whereas liver-like, rancid, and refrigerator/stale off-flavors were rated higher (P ≤ 0.008) for GM steaks. Cardboard, bitter, and rancid off-flavors were higher after 9 months of frozen storage compared to fresh steaks (P ≤ 0.012). Overall tenderness and juiciness of fresh and 9 months frozen steaks did not differ (P > 0.050). In conclusion, there was no detrimental effect on tenderness, juiciness, or flavor when freezing VAC steaks for up to 9 months. Steaks packaged OW were less tender, and the OW GM was less juicy when compared to VAC steaks. Undesirable off flavors were higher in GM vs. LL, OW vs. VAC and after longer cold storage durations.
  • Item
    Why do I want to work for you? An Analysis of Job Satisfaction, Laborer Retention, and Recruitment in the Cattle Feeding Industry
    (May 2023) Summers, Baily N.; Vestal, Mallory Kay; Vestal, Mallory Kay; Lawrence, Ty E.; Marcillo, Guillermo; Pipkin, John; Tarpley, Troy G.
    The Texas Cattle Feeders Association (TCFA) region is the most productive beef cattle region in the United States (TCFA, 2023). Productivity and efficiency are two areas that work hand in hand and employees drive both. To identify areas of growth for the beef cattle industry, assessing concerns of those who hold the future of the industry in their hands, the laborers, is crucial. Along with the challenge of a tightened labor force, the concentration of feedyards in this region poses a unique competition between yards to hire and retain valuable employees. A thorough understanding of laborers' perceptions is imperative to the industry and its' leaders. The primary objective of this study was to identify key themes of feedyard laborers' viewpoints regarding their overall job satisfaction and perceived obstacles of retention and recruitment. Secondary objectives were to observe theme frequencies across feedyard departments and determine if differences in laborers’ perspectives differed between feedyard capacity groups. This study builds upon previous research (Robinson, 2019), which provided benchmark data to gain an understanding of demographics, employee satisfaction, and employee attitudes and opinions. The survey instrument was designed and mailed in January 2019 to 685 laborers employed at 101 feedyards in the TCFA region (Robinson, 2019). Open-ended responses provided personal and accurate portrayals of the respondents' attitudes and opinions. Nine open-ended question written narratives from 146 laborers were analyzed in this study, which employed a phenomenological qualitative approach and coded responses. Coding included identifying patterns of terminology or phrases and allocating a code to the individual responses. Codes were grouped into themes and organized in a codebook to bring summarization. Results revealed the most common themes to be Compensation, Work-Life Balance, Psychological Income, and Work Conditions. Frequencies of themes were examined across feedyard departments, and differences in laborer perceptions between feedyard capacity groups were analyzed using chi square tests. Results indicated that themes of laborer perspectives differed between feedyard capacity groups.
  • Item
    (May 2023) Vareed, Daniel; Bartlett, Michelle; Bartlett, Michelle; Farren, Gene L.; Price, Blake
    Historically speaking, sports and politics have always been intertwined, and in this current time, more attention has been given to this fact. As athletes and their followers continue to become more vocal, they have used their increased voice to highlight controversial issues such as alleged police brutality, voting rights, transgender rights, and other issues as well. While professional athletes often get the spotlight to draw awareness to the discussed topics, collegiate athletes have also drawn light to such issues in the past and are starting to do so more frequently in the modern day. Given this development, the current study surveyed 93 student-athletes at a university located in the Southwest region of the United States. A series of results showed that most student-athletes are open and willing to listen to their teammates and colleagues when they engage in social justice activism. Political affiliation was the strongest indicator for determining whether a student-athlete was open to listening to and engaging in social justice activism. Other strong indicators were race and gender; however, sex was not associated to the social justice activism. Future research may look to engage in whether time in college changes these feelings toward activism and whether chemistry and rapport between teammates play a significant role in affecting social justice activism attitudes on campus.
  • Item
    A Genomic and Economic Analysis of Utilizing Pooled Genotypes in a Commercial Beef Cattle Feedlot Setting
    (May 2023) Prosser, Haleigh M; Perkins, Tommy; Perkins, Tommy; Scott, Matthew; Arnold, Chelsea
    Genotyping individual animals, the primary way to identify the genetic makeup of the animal, comes at a fiscal and logistical cost commercial beef cattle feedlots cannot afford in current markets. The purpose of this study was to utilize DNA pooling and a pooled genome-wide association study (GWAS) to allow the commercial feedlot setting to ascertain the benefits of genomic testing and make predictions contingent on these tests, as well as determine its economic feasibility. A total of 1,956 commercial feedlot cattle (1,715 steers; 241 heifers) completed the project with receival information, carcass data, and tissue samples. DNA was stratified into 79 pools (mean size = 25 individuals) based on receival weight within lot and arrival date and genotyped via GGP Bovine 100K array (Illumina). Data preparation with outlier filtering (OF) and repeated measures (RM) reduced phenotypic variation within pools by removing outlier-driven pools and replicating the pool genotype to an individual level, respectively. Pool average and individual calculated yield grade (CYG) and marbling (MARB), both essential carcass value determinants, served as phenotype data. A cost comparison of pooled and individual genotyping and a cost-benefit analysis of prospective pooling displayed the economic advantage and potential economic feasibility of the process. The RM CYG, OF CYG, RM MARB, and OF MARB trial GWAS identified 20, 10, 27, and 16 significant (p ≤ 0.001) SNPs, respectively. The estimated cost of individually genotyping the study ($105,354) was 4.5 times greater than the estimated pooled genotyping cost ($23,460). Utilizing pooled genotypes to make marketing decisions had a potential benefit-cost ratio of 2.33 (SD = 1.91). This research identified biologically logical associations despite high genetic variability between pools, signifying success in utilizing prospectively pooled DNA in GWAS. Further research and exploration are necessary for developing a successful strategy for its application. With potential benefits that outweigh the cost, the pooled genetic processing and analysis should be further evaluated in additional commercial feedlot settings.
  • Item
    (May 2023) Nguyen, Thinh 1999-; Shrestha, Keshav; Flynn, Nick; Pal, Anirban
    We have studied the Fermi surface characteristics of two Dirac type-II semimetal candidates (Ni, Zr)Te2 using the torque magnetometry technique under the magnetic field up to 35 T and temperature as low as 0.32 K. The torque signal shows clear de Haas-van Alphen (dHvA) oscillations above 20 T for both ZrTe2 and NiTe2 samples. Frequency analysis reveals one major frequency for ZrTe2 at 530 T; whereas there are three distinct frequencies Fα ∼ 72 T, Fβ ∼ 425 T, and Fγ ∼ 630 T for NiTe2. From the analyses of temperature-dependent dHvA oscillations data using the Lifshitz- Kosevich (LK) formula, we observed the effective masses charge carriers to be m*= 0.26me and m* = 0.13me for ZrTe2 and NiTe2, respectively, where me is the free electron mass. The Berry phase (Φ) is calculated to identify the topological nature of ZrTe2 and NiTe2 by constructing the Landau level fan diagram. It is found that Φ ∼ 0 and π for ZrTe2 and NiTe2, respectively. These results strongly suggest that ZrTe2 is a topologically trivial system, whereas NiTe2 is a topologically non-trivial system. These materials’ electronic band structure and Fermi surface were calculated using the density functional theory (DFT). Our DFT results show that the Dirac point is closer to the Fermi level in NiTe2 as compared to that for ZrTe2. Therefore, our torque results could only detect the signal from Dirac quasi-particles for NiTe2, not for ZrTe2.
  • Item
    (May 2023) Mumbulo, Rileigh; Tarpley, Troy G.; Robertson, J. T; Arnold, Chelsea
    Across all U.S. agricultural industries, women represented 14% of primary-operators in 2019. Women in the dairy industry are underrepresented with a 4.1% share of primary-operators compared to their male counterparts. The Journal of Dairy Science has approximately one published article in relation to decision-making systems or human management that includes gender demographics. Past research on agricultural decision-makers provides evidence that a productivity gap exists in male-dominated industries. A survey was conducted to investigate what factors influence a woman to become a primary decision-maker in the dairy industry. Participants were divided into two groups, a high and a low, based on the mean of total respondents’ (n=30) A-WEAI score. A Probit regression model was ran on variables to find correlation between the high group. Results demonstrate that a higher level of education was statistically significant (p>0.039) for respondents within the high A-WEAI score group. Previous research confirms that a higher level of formal education is a central theme shared by women who become decision-makers in the agricultural industries. Industry trends show that the future dairy industry will have more representation of women. As the percentage of women increases in the dairy sector, it may lower the wage for both women and men in the industry. Applicable implications for the dairy industry include bringing awareness to the barriers that women may face, restructuring of intrinsic values, monitoring the pay outlook, and working to make dairy industry employment competitive and progressive.
  • Item
    A Survey Assessing Interpersonal, Academic, and Employability Skills Associated with Participation on an Agriculturally-Based Competitive Team
    (May 2023) McNeill, Lindsey Renae 1992-; Williams, Kevin; Pipkin, John; Baker, Lance A.; Bigham, Gary; Robertson, J. T
    While several studies have assessed the skills produced by competing on agriculture-related judging teams, there are limited published reports assessing these same skills by students on other agriculture competitive teams (Rodeo, Equestrian, Ranch horse). The current study surveyed students across the United States using a 5-point Likert-Type scale to assess interpersonal, academic, and employability skills after participation on collegiate judging (Horse, Meat, Livestock), performance-type (Equestrian, Rodeo, Ranch/Stock), or both teams. The survey was sent to coaches of active teams at 4-yr universities and completed by students (n = 238) at the end of their team’s respective seasons. This study assessed 17 interpersonal, 14 academic, and 19 employability skills, which were previously identified by competitive team alumni in a Delphi Study. Participants were asked to self-assess interpersonal skills pre and post participation, and the means were compared using a paired t-test. Post-participation data from self-assessment of interpersonal, academic and employability skills by members of judging, performance-type, or both teams was analyzed using a one-way ANOVA. Significance was declared at P= 0.05. There was enhancement of interpersonal skills (P = 0.024), academic skills (P= <0.001) and employability skills (P= <0.001) between teams. A Chi-Square was performed for each skill or factor crossed with the type of team on which a student chose to participate. In the interpersonal category (P< 0.045) content knowledge, decision making, memory, networking, and public speaking were all deemed significant. In the academic category (P< 0.045), content knowledge, efficiency, motivation, structure, and test taking ability were deemed significant. Finally, in the employability category, communication skills, confidence, decision making, experience, learned skills/knowledge, multi-tasking, personal drive, and problem solving were all deemed significant (P< 0.043). Students who engaged in agriculturally-based competitive teams enhanced their skills regardless of their chosen team. However, some interpersonal, academic, and employability skills were significantly different between judging and performance competitors.
  • Item
    (May 2023) Martinez, Jose Carlos 06/25/1978-; Revett, Jonathan D.; Von Lintel, Amy; Gamble, Misty
    The work in my thesis is an investigation of abstraction through aerosol-based paintings that synthesize stencils of real-world objects and graffiti-based forms. Graffiti was an outlet in my youth to release anger in response to hard times and trauma. Tagging was a way to cope with my issues, to find a sense of control in the chaos that I faced. After years of doing work as a professional mural artist, my thesis work allowed me to return to my graffiti practice while bringing it to a new level: the level of abstract painting in a gallery setting. Abstraction can deeply communicate meaning and emotions, and my thesis work focuses on trauma experiences in ways that can cathartic and therapeutic for myself and for viewers.
  • Item
    (May 2023) Martinez, Daniel Jacob 1996-; Bhattacharia, Sanjoy; Leitch, Kenneth; Stephen Jones; Matthew Jackson
    This body of work provides a general analysis of the mechanical properties of 316L stainless steel prints that have been generated with laser powder bed fusion (LPBF). Powdered 316L stainless steel was utilized in the selective laser melting process to generate samples suitable for materials analysis. The aim of this body of work is to analyze how a specified LPBF process affects the material properties of 316L stainless steel. Thorough understanding of the effect that the LPBF process has on 316L stainless steel material properties may provide designers and engineers with information that aids in component design and reliability. The findings presented herein demonstrate that the LPBF process produces a state of material properties that are unlike its traditionally manufactured counterparts. Thorough investigation of the tensile properties, hardness, density, and microscopic properties of the material provide a material performance profile. This material profile was compared to the profile of a traditionally manufactured and annealed 316L steel samples. The results show that the use of LPBF can be used to generate high density, high strength components in the as-printed condition. Additionally, Anisotropic material performance was identified and measured in tensile tests, and in metallurgical microscopy.
  • Item
    Using Sensemaking to Examine One Female Television Journalist’s Experiences with Using Social Media Platforms
    (May 2023) Keenan-Kingston, Jacqueline 1987-; Kinsky, Emily; Mallard, Jessica; Garcia, Nancy; Drumheller, Kristina
    Using the lens of sensemaking and the theory of parasocial relationships, this autoethnography examines the social media harassment faced by one female television broadcast journalist who has worked in local television news for more than 15 years. Female journalists are harassed more often and face higher rates of violence on and offline than their male colleagues (Chen et al., 2020). These hazards make their critical work more difficult and dangerous. When leaving the news industry appears to be the only way for female journalists to protect themselves, society risks a nocuous void of voice. Many female journalists are failed by their employers’ social media policies which protect the news organization rather than the employee. Based on previous literature and the lived experience of the author, broadcast journalists are more likely to be protected by news directors who acknowledge and mitigate female journalists’ unique risks and prepare a safety plan to utilize when a threat arises.