DAMEnames

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Search for a W’ Boson Coupling to Third Generation Fermions with Semi-Leptonic Final States in Proton-Proton Collisions
(2024-07-25) Luo, Sifu; Eusebi, Ricardo; Dutta, Bhaskar; Safonov, Alexei; Moreno-Centeno, Erick
The Standard Model of fundamental particles and their interactions (SM) has accurately pre- dicted a large expanse of experimental phenomena since it was introduced in the 1970’s. A recent instance is the discovery of the Higgs boson in 2012, whose existence and other properties were predicted by the SM [1] [2]. However, the Standard Model is far from a complete theory and currently does not have explanations or predictions for neutrino masses, the presence of dark mat- ter, the matter-antimatter asymmetry in the universe, and other pressing questions. Perhaps a hint to understand the deficiencies of the Standard Model lies on those experiments whose results are in tension with the Standard Model predictions. One such experiment compares the decay of B mesons to the different leptons, B → D∗lνl, and evaluates the ratio R(D), which is a test of lep- ton universality in the B sector. The published results [3] indicate a deviation from the Standard Model prediction. This deviation can be explained by the introduction of another particle, the W′, which shares similar properties with its Standard Model counterpart, the W boson, but couples exclusively to c b t quarks, and τ ντ leptons. This dissertation presents a search for a W′ coupling exclusively to b and t quarks. Production of such a W′ can occur most copiously as an intermediate step in the decay products of top quark pair production in association with an initial state b-quark. This search is performed on datasets of proton-proton collision at a center of mass energy of 13 TeV collected with the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider. The signal extraction is enhanced by the development of a kinematic fitter that significantly im- prove the reach of the search, allowing strong upper limits on the cross-section of such a W′ in the mass region of 300 GeV to 1100 GeV. This is the first limit in the record set on a W′ of mass lower than 1000 GeV.
Parents and Science Education: Parents' at Home Learning Experiences During the COVID Lockdown
(2024-05-28) Porter, Cherilyn Renee; Yalvac, Bugrahan; Olson, Joanne; Singleton, Julie; Skaggs, Chris
Between 2020 and 2023, the COVID-19 lockdown resulted in massive school closures. Parents now had their children being educated at a distance and had to balance their work and life in a new way. This shift to home-based learning cultivated a new experience for parents. I conducted a phenomenological study with five participants. The phenomenon under investigation was a parent’s experiences with educating their child at home, with particular emphasis on science education, and the meaning the parent attributed to those experiences. Of the five parents who volunteered to participate in this study, one parent had already been home schooling her children when the lockdown occurred and three were current public educators. I collected data from the participants utilizing a survey and interview protocol. The analyses of the survey responses and the interview transcripts revealed four main themes. (1) The experiences participants lived through were overwhelming both in terms of their time-management and emotional capacity. (2) They were rewarding as they allowed growth in parenting skills and an appreciation for community. (3) Each participant was reflective of education’s role in their lives and found positive and negative aspects. (4) Participants were hopeful for the future and planning how to best help improve education. The study findings generated some implications that parents should focus on some particular skills in homeschooling and school districts must focus efforts on building relationships with parents in their community to encourage involvement and increased discourse regarding the nature of science. In light of other research regarding the lockdown, considerations can be made. (1) Schools should consider the best practice for integrating situated learning and assessment based on parent-defined success. (2) School districts must implement strategies to support parent involvement and accurate understanding of the NOS. (3) Parents must fight to ensure the best for their children and that requires keeping track of policy and maintaining partnerships with public educators. (4) Researchers can support these goals by focusing on describing what makes students successful, not to force comparisons of which modality is always best, and describe how to address parents NOS understanding.
An Investigation of the Genomic Space and Search for Hydrocarbon Biosynthetic Genes in the Green Microalga Botryococcus braunii
(2023-12-06) Boland, Devon Joseph; Straight, Paul; Devarenne, Timothy P; Raushel, Frank; Han, Arum
The colonial green microalga Botryococcus braunii is well known for producing liquid hydrocarbons that can be utilized as biofuel feedstocks. B. braunii is taxonomically classified as a single species made up of three chemical races, A, B, and L, that are mainly distinguished by the hydrocarbons produced. These hydrocarbons can be refined into chemically identical petroleum fuel equivalents. Making them a unique organism for the production and/or sourcing of biofuel feedstocks. There has long been a debate over the chemical race classification system used for B. braunii and if these chemical races are a single or different species. Here data is presented from a comparative genomics analysis (Chapter III) from newly assembled draft nuclear genomes of the A and L chemical races (Chapter II). This comparative analysis revealed many differences at the genomic level between all three chemical races, suggesting these chemical races are in fact distinct and different species within the genus Botryococcus. A reclassification is proposed of the three chemical races to the following species names: Botryococcus alkenealis (A race), Botryococcus braunii (B race), and Botryococcus lycopadienor (L race). Great efforts have been spent trying to elucidate and characterize the biosynthetic pathways responsible for hydrocarbon production in Botryococcus. Previous work has elucidated a nearly full biosynthetic pathway B. braunii (B race). Recently, the first committed step and all pathway intermediates in the hydrocarbon biosynthetic pathway for B. lycopadienor was elucidated. The remaining step in the pathway is the identification and characterization of the proposed reductase(s) that serially reduces these hydrocarbon intermediates to form lycopadiene. Here (Chapter IV), great efforts are detailed in the attempted identification of these reductase(s).
An Investigation and Proof of Concept for Subcritical Ultra-Low Temperature Organic Rankine Cycle
(2023-12-01) Smith, Jimmie Ray; Pate, Michael B; Delgado-Marquez, Adolfo; Tsvetkov, Pavel V
In support of a major push towards a greener world using renewable energy, the Organic Rankine Cycle (ORC) is a promising area of exploration for generating power from low grade thermal sources. An ORC is able to operate at lower temperatures and at reduced temperature differentials due to its use of alternative working fluids, rather than conventional water. This study seeks to prove the viability of an ultra-low grade ORC operating with a 10 degree temperature differential between the high to low temperature reservoirs. To accomplish this task, a carbon dioxide Organic Rankine Cycle was operated at a steady state marked by twenty minutes of unchanging states, thus achieving the correct test conditions for the chosen working fluid. A wide assortment of experimental data was then captured and used for analysis and modeling. The Engineering Equation Solver (EES) software was utilized to model the behavior of a Rankine Power Cycle that is capable of using different working fluids (i.e. an ORC with carbon dioxide) operating with a 10 degrees Fahrenheit temperature differential between 40 degrees Fahrenheit and 50 degrees Fahrenheit (i.e. temperature reservoirs). After comparing multiple refrigerants using the cycle model under idealized conditions, carbon dioxide was chosen with a theoretical net work production of 1.73 Btu/lbm and a 1.91% thermal efficiency. This latter value is comparable to the Carnot efficiency of 1.96% since the modeled pumps and turbine assumed a 100% isentropic efficiency, and heat transfer in the heat exchangers was assumed to occur over a 0 degrees Fahrenheit temperature difference. The test facility used in this study was designed and constructed based on the results of the simulation from the aforementioned cycle model. Even so, it was necessary to make numerous system modifications to overcome unforeseen problems once components and parts were procured (i.e. delivered to REEL) and assembled. Specifically, modifications had to be made to the condenser and chillers in order to achieve consistent liquid conversions in the heat exchangers. Furthermore, the original experimental system was assembled with a throttle valve to replace and simulate the pressure drop across a Tesla turbine, to be incorporated in the system at a later date. The results from the throttle valve testing indicated that if a turbine had been installed then the ORC test rig could achieve a power output of 1.91 Btu/lbm and a power draw of 6.05 Btu/lbm. However, the carbon dioxide test facility assembled and operated had mismatched carbon dioxide circulating pumps with the isentropic efficiency measured to be 4.46% and with an excessive power draw of 6.05 BTU/lbm. Even though these pumps will be switched out in the future, in terms of this study, the net work of -4.14 BTU/lbm is less important than the simulated 1.91 Btu/lbm power output achieved. The heat exchangers were analyzed and determined to have efficiencies of 19.2% and 24.5% for the evaporator and condenser, respectively. In summary, evaluating and testing additional working fluids, along with modifying the pumps to have increased efficiencies for low viscosity fluids, such as carbon dioxide, should allow for increased overall cycle efficiency and the potential to generate net positive power in the future.
Molecular Dynamics Simulations of Dislocation Mobility in the Transonic Regime
(2023-10-19) Duong, Ta Dinh; Demkowicz, Michael J; Pharr, George; Cagin, Tahir; Wilkerson, Justin
Determining dislocation mobility, i.e., the relationship between dislocation velocity and shear stress, is essential for predicting material response to external loading. However, dislocation mobility is not fully understood, especially for dislocations moving near or above a material's lowest sound speed. We use molecular dynamics to investigate the effect of free surfaces on the mobility of an edge, a screw, and a twinning dislocations in single crystal copper. We find that the upper limit of dislocation velocity depends on the dislocation type. By correlating instantaneous velocities v and resolved stresses tau, we show that the mobility law of each dislocation type can be decomposed into piece-wise continuous ranges of uniform motion separated by bands of forbidden velocity. The lower limiting velocity for uniform motion of all dislocations is the Rayleigh wave speed. When forced to propagate at an average velocity greater than c^R, dislocations exhibit periodic, intermittent, discrete jumps in instantaneous velocity between c^R and higher velocity branches of the mobility law. Bands of forbidden velocity may be calculated directly from the velocity dependence of dislocation drag coefficients. These findings provide atomistic insights of plastic deformation near free surface under high strain-rate loading.
Deterministic and Probabilistic Deep Learning in Predicting Reactor Physics of a Source-Driven Subcritical System
(2023-11-15) Gatchalian, Ronald Daryll Espino; Tsvetkov, Pavel V; Ford, John R; McDeavitt, Sean M; Pate, Michael B
Spatial, spectral, and modal effects prominent in subcritical regime led to challenges in evaluating integral physics parameters of source-driven subcritical systems. These effects cannot be natively accounted by standard experimental techniques based on Point Reactor Kinetics (PRK) primarily developed for critical systems. Deviation from PRK assumptions led to non-ideal response such as dependence to detector position of evaluated reactivity coefficient k-effective, presence of multiple-Alpha modes, and increasing reactivity coefficient k-effective bias as system becomes deeply subcritical. Capability to determine reactivity coefficient k-effective and other kinetics and subcritical parameters from system observables is paramount for ensuring nuclear safety by maintaining reactivity margins in Subcritical Assemblies (SCA), and safe approach to critical state in research reactors. This dissertation introduces a data-driven methodology based on Deep Learning (DL) for predicting the reactor physics parameters of an SCA by mapping from directly measurable properties like core arrangement, reaction rates, and detector response. Deterministic and Probabilistic deep neural networks were configured through supervised learning approach using simulation data from physics-based neutronics calculations covering both stationary state in source-equilibrium, and in dynamic state in Pulsed Neutron Source experiment. Optimized hyperparameters, architecture priors, preprocessing technique, and input data modality were assessed by inference on a withheld Test set. Test metrics showed accurate DL predictions with coefficient for determination greater than or equal to 0.99 for reactivity coefficient k-effective, lambda effective, orbital angular momentum of the unpaired nucleon, ks, Alpha, and theoretical intensity-independent effective similarity parameter that surpassed baseline performance derived from statistical and criticality safety considerations with superior accuracy and scalability than traditional Machine Learning approaches. Compared to standard reactivity measurement techniques, such as Amplified Source, Area-ratio, and Slope-fit methods, DL consistently provided accurate predictions well within plus-minus1$ of true values regardless of source location and subcriticality, eliminating the need for auxiliary corrective measures. Other physics parameters with no equivalent experimental techniques were also accurately predicted. This capability is unique from neutronics evaluations as measurable quantities are leveraged as predictors. These advantages extended to probabilistic DL capable of modelling aleatoric and epistemic uncertainties thus providing confidence bounds. Overall, the novel application of DL in subcritical physics evaluation shows promise in an operational setting, addressing current analytical challenges which can enhance the safety and performance of SCAs, and emerging subcritical nuclear systems for waste transmutation.
Reproductive Microbiomes and Cytokine Profiles of Beef Cattle in Relation to Fertility
(2023-12-04) Smith, Molly Sloan; Poole, Rebecca K; Pohler, Ky G; Dass, Sapna C; Farnell, Morgan B
Cytokines influence inflammatory signals that can upregulate immune responses and influence fertility. Additionally, shifts in commensal bacteria (for example, Lactobacillus in the phylum Firmicutes) in the bovine vaginal microbiome are associated with compromised fertility. Together, immune responses and the reproductive microbiome may result in nonproductive females that place financial burdens on ranchers. A more complete understanding of the immune system and reproductive microbiome may play an influential role in improving cattle reproduction and performance. Section 3 characterizes the reproductive microbiome and cytokine concentrations before artificial insemination (AI) in vaginal and uterine flushes from postpartum beef cows. Bos indicus-influenced beef cows were enrolled in the Bos indicus prostaglandin (PG) 5-day + controlled intervaginal drug-releasing (CIDR) estrus synchronization protocol. Pregnancy status was determined by transrectal ultrasonography, cows were identified as either Open or Pregnant. Uterine concentrations of interferon (IFN)Gamma, interleukin (IL)1Alpha, and IL21 were greater in Open than in Pregnant cows. Regardless of pregnancy status, uterine IL13 increased from d-3 to d-1. Uterine relative abundance of the phylum Firmicutes decreased from d-3 to d-1 in Open cows and the phylum Tenericutes increased from d-3 to d-1 in Pregnant cows. In Section 4, our aim was to characterize the circulating cytokines and the vaginal microbiome of Bos indicus females prior to fixed-time AI (FTAI). Bos indicus females on four operations were subjected to the 7-day CO-Synch + CIDR protocol. Transrectal ultrasonography determined pregnancy status for resulting Open females and Pregnant females. Circulating concentrations of the proinflammatory cytokines IFNGamma, IL1Alpha, and TNFAlpha were greater in Open females compared to Pregnant females. Interestingly, circulating concentrations of the anti-inflammatory cytokines IL13, IL1F5, and IL21 were greater in Open females compared to Pregnant females. The vaginal relative abundance of Firmicutes differed between CIDR IN, CIDR OUT, and AI days. A shift in relative abundance between CIDR IN, CIDR OUT, and AI days was observed for the phylum of Proteobacteria and Bacteroidetes. Overall, for Section 3 and Section 4, a difference in cytokine profiles and the reproductive microbiome were found before FTAI. Additionally, relative abundances within the vagina differ between ranches of similar genetics and regions.
Studies of High-Temperature Deformation Processes in Earth Materials: Experimental Investigations and Theoretical Modeling
(2023-12-04) Prakash, Abhishek; Kronenberg, Andreas; Duan, Benchun; Lamb, William; Newman, Julie; Radovic, Miladin
Experimental and theoretical investigations play a crucial role in advancing our understanding of high-temperature deformation processes, responsible for the plasticity and strength of the middle to lower crustal layers of continental lithospheres, plate boundaries, and subducting oceanic plates of subduction zones. I have conducted triaxial deformation experiments on naturally occurring perthitic single crystal feldspars to determine their plastic anisotropy, effects of solid solution, and exsolution and water on their mechanical properties. Deformation experiments were performed using a Griggs solid-medium apparatus, maintaining temperatures in the range of 800-900 degrees Celsius, strain rates (Epsilon) at 1.6x10^-6 s^-1 , and confining pressures ranging from 0.5 to 1.5 GPa. My findings revealed that feldspar samples compressed in [012] direction show the lowest flow strengths, while those deformed along the [001] direction displayed the highest flow strength. Deformation and strength measured in the [012] direction at different pressures (0.75-1.5 GPa) and temperatures (900 degrees Celsius) demonstrate that water weakening in feldspars due to intracrystalline defect interactions with hydrous defects depends on the water fugacity. Earthquakes occurring at depths beyond 15 km are often attributed to low effective pressures, owing to elevated pore pressures, as hydrous silicates such as serpentine dehydrate. However, recent assessments of intermediate-depth earthquakes have revealed that temperatures and pressures of seismogenic subducting slabs do not always correspond to antigorite serpentine, amphiboles, or talc dehydration. Altered mantle rocks of the upper lithosphere and mantle wedges also contain magnesian carbonates, which are stable to great depths. Carbonates of downgoing slabs are weaker than anhydrous mantle silicates. My theoretical modeling study of magnesian carbonate horizons within altered peridotite demonstrates that intermediate-depth earthquakes can result from strain localization within carbonates and thermal shear instabilities that lead to seismic rupture. Models of shear instabilities in ultramafic mantle rocks, are based on grain size-sensitive creep and changes in rheology with changes in grain size. Such analyses cannot be implemented for magnesian carbonates without a better understanding of the kinetics governing grain growth and refinement. The grain growth kinetics study of pure magnesite and Ca-rich magnesite show nearly parabolic grain growth for short annealing times in pure magnesite, when curved grain boundaries are dominant.
Studies of High-Temperature Deformation Processes in Earth Materials: Experimental Investigations and Theoretical Modeling
(2023-12-04) Prakash, Abhishek; Kronenberg, Andreas; Duan, Benchun; Lamb, William; Newman, Julie; Radovic, Miladin
Experimental and theoretical investigations play a crucial role in advancing our understanding of high-temperature deformation processes, responsible for the plasticity and strength of the middle to lower crustal layers of continental lithospheres, plate boundaries, and subducting oceanic plates of subduction zones. I have conducted triaxial deformation experiments on naturally occurring perthitic single crystal feldspars to determine their plastic anisotropy, effects of solid solution, and exsolution and water on their mechanical properties. Deformation experiments were performed using a Griggs solid-medium apparatus, maintaining temperatures in the range of 800-900 degrees Celsius, strain rates (Epsilon) at 1.6x10^-6 s^-1 , and confining pressures ranging from 0.5 to 1.5 GPa. My findings revealed that feldspar samples compressed in [012] direction show the lowest flow strengths, while those deformed along the [001] direction displayed the highest flow strength. Deformation and strength measured in the [012] direction at different pressures (0.75-1.5 GPa) and temperatures (900 degrees Celsius) demonstrate that water weakening in feldspars due to intracrystalline defect interactions with hydrous defects depends on the water fugacity. Earthquakes occurring at depths beyond 15 km are often attributed to low effective pressures, owing to elevated pore pressures, as hydrous silicates such as serpentine dehydrate. However, recent assessments of intermediate-depth earthquakes have revealed that temperatures and pressures of seismogenic subducting slabs do not always correspond to antigorite serpentine, amphiboles, or talc dehydration. Altered mantle rocks of the upper lithosphere and mantle wedges also contain magnesian carbonates, which are stable to great depths. Carbonates of downgoing slabs are weaker than anhydrous mantle silicates. My theoretical modeling study of magnesian carbonate horizons within altered peridotite demonstrates that intermediate-depth earthquakes can result from strain localization within carbonates and thermal shear instabilities that lead to seismic rupture. Models of shear instabilities in ultramafic mantle rocks, are based on grain size-sensitive creep and changes in rheology with changes in grain size. Such analyses cannot be implemented for magnesian carbonates without a better understanding of the kinetics governing grain growth and refinement. The grain growth kinetics study of pure magnesite and Ca-rich magnesite show nearly parabolic grain growth for short annealing times in pure magnesite, when curved grain boundaries are dominant.
Studies of High-Temperature Deformation Processes in Earth Materials: Experimental Investigations and Theoretical Modeling
(2023-12-04) Prakash, Abhishek; Kronenberg, Andreas; Duan, Benchun; Lamb, William; Newman, Julie; Radovic, Miladin
Experimental and theoretical investigations play a crucial role in advancing our understanding of high-temperature deformation processes, responsible for the plasticity and strength of the middle to lower crustal layers of continental lithospheres, plate boundaries, and subducting oceanic plates of subduction zones. I have conducted triaxial deformation experiments on naturally occurring perthitic single crystal feldspars to determine their plastic anisotropy, effects of solid solution, and exsolution and water on their mechanical properties. Deformation experiments were performed using a Griggs solid-medium apparatus, maintaining temperatures in the range of 800-900 degrees Celsius, strain rates (Epsilon) at 1.6x10^-6 s^-1 , and confining pressures ranging from 0.5 to 1.5 GPa. My findings revealed that feldspar samples compressed in [012] direction show the lowest flow strengths, while those deformed along the [001] direction displayed the highest flow strength. Deformation and strength measured in the [012] direction at different pressures (0.75-1.5 GPa) and temperatures (900 degrees Celsius) demonstrate that water weakening in feldspars due to intracrystalline defect interactions with hydrous defects depends on the water fugacity. Earthquakes occurring at depths beyond 15 km are often attributed to low effective pressures, owing to elevated pore pressures, as hydrous silicates such as serpentine dehydrate. However, recent assessments of intermediate-depth earthquakes have revealed that temperatures and pressures of seismogenic subducting slabs do not always correspond to antigorite serpentine, amphiboles, or talc dehydration. Altered mantle rocks of the upper lithosphere and mantle wedges also contain magnesian carbonates, which are stable to great depths. Carbonates of downgoing slabs are weaker than anhydrous mantle silicates. My theoretical modeling study of magnesian carbonate horizons within altered peridotite demonstrates that intermediate-depth earthquakes can result from strain localization within carbonates and thermal shear instabilities that lead to seismic rupture. Models of shear instabilities in ultramafic mantle rocks, are based on grain size-sensitive creep and changes in rheology with changes in grain size. Such analyses cannot be implemented for magnesian carbonates without a better understanding of the kinetics governing grain growth and refinement. The grain growth kinetics study of pure magnesite and Ca-rich magnesite show nearly parabolic grain growth for short annealing times in pure magnesite, when curved grain boundaries are dominant.
Studies of High-Temperature Deformation Processes in Earth Materials: Experimental Investigations and Theoretical Modeling
(2023-12-04) Prakash, Abhishek; Kronenberg, Andreas; Duan, Benchun; Lamb, William; Newman, Julie; Radovic, Miladin
Experimental and theoretical investigations play a crucial role in advancing our understanding of high-temperature deformation processes, responsible for the plasticity and strength of the middle to lower crustal layers of continental lithospheres, plate boundaries, and subducting oceanic plates of subduction zones. I have conducted triaxial deformation experiments on naturally occurring perthitic single crystal feldspars to determine their plastic anisotropy, effects of solid solution, and exsolution and water on their mechanical properties. Deformation experiments were performed using a Griggs solid-medium apparatus, maintaining temperatures in the range of 800-900 degrees Celsius, strain rates (Epsilon) at 1.6x10^-6 s^-1 , and confining pressures ranging from 0.5 to 1.5 GPa. My findings revealed that feldspar samples compressed in [012] direction show the lowest flow strengths, while those deformed along the [001] direction displayed the highest flow strength. Deformation and strength measured in the [012] direction at different pressures (0.75-1.5 GPa) and temperatures (900 degrees Celsius) demonstrate that water weakening in feldspars due to intracrystalline defect interactions with hydrous defects depends on the water fugacity. Earthquakes occurring at depths beyond 15 km are often attributed to low effective pressures, owing to elevated pore pressures, as hydrous silicates such as serpentine dehydrate. However, recent assessments of intermediate-depth earthquakes have revealed that temperatures and pressures of seismogenic subducting slabs do not always correspond to antigorite serpentine, amphiboles, or talc dehydration. Altered mantle rocks of the upper lithosphere and mantle wedges also contain magnesian carbonates, which are stable to great depths. Carbonates of downgoing slabs are weaker than anhydrous mantle silicates. My theoretical modeling study of magnesian carbonate horizons within altered peridotite demonstrates that intermediate-depth earthquakes can result from strain localization within carbonates and thermal shear instabilities that lead to seismic rupture. Models of shear instabilities in ultramafic mantle rocks, are based on grain size-sensitive creep and changes in rheology with changes in grain size. Such analyses cannot be implemented for magnesian carbonates without a better understanding of the kinetics governing grain growth and refinement. The grain growth kinetics study of pure magnesite and Ca-rich magnesite show nearly parabolic grain growth for short annealing times in pure magnesite, when curved grain boundaries are dominant.
Sometimes Too Hungry to Concentrate: Nontraditional and Traditional First-Generation Students’ Educational Food Practices
(2020-03-02) Cisneros, Marissa R.; Mcintosh, William A; Gatson, Sarah; Moore, Wendy L; Plankey-Videla, Nancy
In the long-valued narrative of meritocracy in the United States, ‘Pulling oneself up by the bootstraps’ is a myth which has been enacted to undermine the structural, even intentional, reality of the inequity between people. In order to situate the structural reality of inequity I focus this research on San Antonio, Texas. I first provide a case study of San Antonio in which I am able to evaluate how genocidal tactics through dispossession has created a classed and racialized inequity of resources. In order to explicate how this inequity is continued I focus this research on higher education. Literature on low rates of educational success of marginalized students tend to focus on how to greater prioritize the role of ‘student’. Most literature identifies individualistic methods to increase educational success of marginalized students. To counter this, I apply an intersectional approach to Bourdieu’s theory of practice to investigate how differential hazards and barriers negatively influence food experiences in higher education. I do this by collecting survey data on two different marginalized groups’ (nontraditional and first-generation students) food practices at the higher education institution, Texas A&M University San Antonio. I use logistic regression to analyze how work effects campus meal skipping while controlling for appropriate variables by student label. I then use logistic regression to identify propensity to use alternative food networks controlling for appropriate variables by student label. From this analysis I illuminate how efforts to obtain food in a field of institutional foodscape, varies by differential barriers and burdens within higher education putting strain on educational access and success. These barriers and burdens are dictated by the individual’s personal and socio-historical interactions with said institution. This navigation is further affected by the interaction of capital; not only to the development of the individual’s habitus but also ability to interact and take full advantage of access and hurdles of said foodscape barriers and burdens.
Enhancing the Hardware-Based Advanced Encryption Standard Implementation for Optimized Performance in Cyber-Physical Systems
(2023-11-30) Tariq, Usama; Crosby, Garth V; Fink, Rainer J; Davis, Katherine
Cyber-Physical Systems play a pivotal role in critical infrastructures but face distinct security challenges. Traditional software-based security measures often disregard to account for the resource limitations that these systems encounter. Field Programmable Gate Arrays offer a solution, enabling hardware-based cryptographic implementations to enhance security. This study delves into the design and analysis of optimized variants of cryptographic encryption implemented on hardware, shedding light on design methodologies and optimization techniques. Our research includes physical verification, rendering the encryption core readily applicable to be deployed in existing systems. Notably, this study goes beyond the existing research landscape, where the focus on specific metrics often neglects the holistic perspective. Our performance analysis, with a particular emphasis on throughput, undergoes rigorous scrutiny and provides a comprehensive view previously unexplored. This work significantly contributes to enhancing security by introducing efficient hardware-based cryptographic solutions and advancing the field with a comprehensive performance analysis.
Behind the Curtain of Grant Writing: A Content Analysis of Funded Proposals
(2023-12-04) Caldwell, Cassidy Jean; Young, Jemimah; Hill-Jackson, Valerie; Neshyba, Monica
This research explores the intricate landscape of grant procurement for global experiences situated in the field of education. Global experiences are widely recognized as transformative opportunities that foster intercultural competence and enrich learning environments. However, securing funding for these experiences remains a challenge filled with competition and complexity. Grant procurement, particularly for global experiences, poses many challenges. Applicants must navigate intricate application procedures, articulate project goals succinctly, and align with funding priorities. Moreover, the competitive nature of grant procurement places immense pressure on applicants to craft compelling proposals. This study focuses on a selection of federally funded grants awarded by the United States Department of Education in the 2020 funding year. The objectives of this research are twofold. Firstly, I aim to analyze awarded grant proposals to identify underlying themes, strategies, and factors contributing to their funding success. Secondly, I explore the unique characteristics and commonalities among successful proposals. The research methodology encompasses rigorous content analysis techniques, enabling a detailed examination of narratives, objectives, and methodologies within the awarded proposals. The subsequent discussion and implications sections present the study's detailed findings and reflect their broader implications. In conclusion, this research enriches our understanding of grant procurement strategies in the context of global experiences. By shedding light on the dynamics of successful funding, the study empowers educators and researchers with insights that can shape the future of transformative educational opportunities.
Do Liver Abscesses in Beef x Dairy Cattle Influence Postmortem Metabolites and Lean Color?
(2023-11-29) Schwartz, Trent E.; Savell, Jeffrey W; Gehring, Kerri B; Smith, Stephen B; Haneklaus, Ashley N; Anderson, David P.
Beef x Dairy (BxD) steers (n = 537) were identified and a subset (n = 201) were evaluated for the presence and severity of liver abscesses. Carcasses were selected (n = 30) to determine the relationship between liver abscesses, metabolites, and lean color. Three abscess categories were identified, 1) MAJOR (A+), 2) MINOR (A-,A), and 3) NORMAL (0). Liver, and pre-rigor M. sternomandibularis (Pre-Sterno) tissues were collected. Carcass data were recorded, post-rigor M. sternomandibularis (Post-Sterno) excised, and instrumental color and pH measured. Beef strip loins were collected (n = 30); one steak was frozen for further analyses and two steaks from each loin were evaluated for instrumental color over 5 d. Liver, Pre-Sterno, Post-Sterno, and strip loin tissue were evaluated for Glucose-6-Phosphate (G-6-P), glucose, glycogen, lactate, and citrate concentration. Liver abscess rate was 43.78% (n = 201), with 29.36% severe. There was no (P = 0.4374) difference in pH, and NORMAL possessed the highest in-plant a* values (P = 0.0211). For instrumental color over 5 d, MINOR had the highest L* values (P = 0.0035), MAJOR the highest a* (P = 0.0020) and chroma values (P < 0.0001), MAJOR and MINOR the highest b* values (P < 0.0001), and NORMAL the highest hue values (P < 0.0001). MAJOR had the highest ratio of oxymyoglobin (P < 0.0001) and deoxymyoglobin (P = 0.0088), and NORMAL the highest metmyoglobin (P < 0.0001). NORMAL had the most liver G-6-P (P = 0.0012), least liver glycogen (P = 0.342), most Pre-Sterno glucose (P = 0.0020), and most strip loin G-6-P (P = 0.0026). MAJOR contained the most liver glucose (P = 0.0054), and strip loin citrate (P = 0.0436). MAJOR and MINOR had the most liver glycogen (P = 0.0342), leading to the highest liver glycolytic potential (P = 0.0245). Initial a* values revealed a redder color for NORMAL early postmortem, but metabolite differences influenced higher color stability for MAJOR and MINOR over 5 d. Overall, differences in color and color stability of strip loins indicate that there could be a relationship between liver abscesses and postmortem lean color.
Prompting LLMs for Zero-Shot Next-Item Recommendation
(2023-12-01) Guo, Junyu; Caveerlee, James; Yang, Tianbao; Zou, Na
Recommendation systems can offer personalized suggestions based on user data, enhancing user experiences. Sequential recommendation is a specific subcategory of recommendation systems that focuses on the order and context of previous interactions to offer a sequence of item suggestions. Large language models (LLMs) have demonstrated exceptional prowess in tasks involving commonsense reasoning, knowledge utilization, and task generalization. In particular, they have exhibited remarkable zero-shot performance in numerous natural language processing (NLP) tasks, showcasing their capacity to recommend without extensive training data. This thesis explores the untapped potential of integrating LLMs into sequential recommendations to enhance performance and elevate the user experience. However, this endeavor faces three primary challenges: (i) The huge recommendation space poses significant challenges to LLM-based recommendations, (ii) LLMs face a fundamental constraint that it is not feasible to include all possible items in the prompt, and (iii) for items that appear infrequently in the training of an LLM, it can be challenging to model these items well to make recommendations. In this thesis, we propose a prompting strategy called zero-shot next-item recommendation (NIR) prompting to guide LLM to make next-item recommendations. Specifically, NIR-based strategies involve using external modules to generate candidate projects based on user filtering. Our strategy uses a 4-step prompt to guide GPT-3 to learn the user’s preferences through the user’s past interaction history and recommend a ranked list of K movies. We evaluate the proposed method using GPT-3 on the MovieLens 100K dataset and show that it achieves strong zero-shot performance. Additionally, we also demonstrate that LLMs can be affected by biases like position bias and popularity bias. By employing specialized prompting and bootstrapping strategies, these biases can be mitigated.
There is Nothing So Stable as Change: The Day-to-Day Stability of Safety Climate in the Offshore Oil and Gas Industry
(2023-11-29) Dumlao, Stefan Val; Payne, Stephanie C; Arthur Jr., Winfred; Peres, S Camille; Zhang, Bo
Safety climate is employees’ shared perceptions of the prioritization of safety in the workplace and of the value that organizations place on safe behaviors. Despite its importance in predicting adverse workplace safety-related events, organizations in the oil and gas industry typically only measure safety climate annually, at best. Absent an intervention or adverse event, the extant literature largely assumes that safety climate is a stable construct, though there are very few studies that directly test this assumption. If this assumption is incorrect, organizations may be effectively blind to changes in safety climate for months between assessments, losing an important indicator of an impending incident. To address this gap, this study followed two separate organizational samples of offshore oil and gas workers (Sample 1 n = 34; Sample 2 n = 36) for a period of 28 days, commonly referred to as a “hitch.” A total of 1,623 daily observations of safety climate were collected. Overall, the daily means, standard deviations, and 1-day lagged correlations of safety climate remained relatively stable over the course of the hitch. Despite this observed stability, the relationship between any two measurements of safety climate significantly diminished as the amount of time between measurements increased. Dynamic structural equation modeling revealed that some individuals demonstrated much more stable safety climate perceptions than others, but none of the study variables could be used to explain this stability. Implications for safety climate theory and measurement of safety climate are discussed.
Understanding Photoluminescence Quantum Yield In Cesium Lead Tribromide Nanocrystals
(2023-11-30) Mireles Villegas, Noel; Sheldon, Matthew T; Banerjee, Sarbajit; Yan, Xin; Belyanin, Alexey
Semiconducting nanoparticles have played a pivotal role in advancing optoelectronic technologies. The photoluminescence quantum yield (PLQY), which measures emitted photons relative to absorbed photons, stands as a critical performance metric for these materials, directly influencing device performance. In the case of CsPbX3 (X = Cl^-1, Br^-1 , I^-1 ) nanocrystals (NCs), the electronic structure is determined through the interactions of molecular orbitals within the PbX6^-1 repeating unit. The most prevalent crystal defect in these materials is halide vacancies, which can locally confine excited carriers, resulting in carrier relaxation through non-radiative recombination mechanisms. This dissertation focuses on understanding the formation of electronic traps within CsPbBr3 NCs and designing effective strategies to mitigate their impact and occurrence. Chapter 2 introduces two precise PLQY measurement methods for colloidal solutions: one compares emission spectra to a reference standard, and the other outlines a custom integrating sphere setup. This chapter provides comprehensive guidance for accurate PLQY measurement, with a particular focus on CsPbBr3 NCs, given that their absorption and emission properties influence PLQY measurement design. Chapter 3 delves into the design of saturated ligand solutions (SLSs), which I propose as a better solvent system for CsPbBr3 NCs. This endeavor involves a series of iterations with the SLSs formulation to identify specific ligand species conducive to optimal surface trap passivation. Our unique approach to the SLS preparation process enables the introduction of substantial quantities of ligands, previously unachievable through direct ligand addition. Concurrently, the SLSs facilitate continuous dilution of the colloidal solution without compromising the structural and optoelectronic quality of the NCs, addressing a significant field limitation. These methods present novel opportunities to gain insights into ligand interactions within perovskite systems and offer tailored solutions designed for perovskite materials. Lastly, Chapter 4 demonstrates the potential to limit the impact of electronic trap states in CsPbBr3 NCs when they are incorporated into solution-phase superlattices. Superlattices enable enhanced interparticle electronic coupling interactions due to the close proximity of individual NCs. This results in a more delocalized electronic structure and improved radiative recombination efficiency, offering insights into strategies for enhancing radiative recombination and outcompeting the kinetics of non-radiative electronic processes.
Boar Reproductive Microbiomes in Relation to Sperm Quality and Toll-Like Receptor Expression
(2023-12-04) McAnally, Brooke Elizabeth; Poole, Rebecca K; Wiegert, Jeffrey G; Dass, Sapna C; Clement, Tracy M
The standardization of artificial insemination practices in the swine industry has led to a greater demand for efficiently produced, healthy, fertile semen doses from boar stud operations. However, bacterial contamination of boar semen is a major concern as certain bacteria can be pathogenic and exert adverse effects on spermatozoa. Most bacteria have been identified using culture-based methodology, yet few studies have characterized the bacterial communities using more precise technologies such as 16S rRNA sequencing. The study in Section 3 sought to fill this gap by describing the boar semen microbiome using 16S rRNA sequencing. Semen doses from two different boar stud operations were sampled for five days. During this period, sperm quality parameters (motility, morphology, agglutination, etc.) and microbiome samples were collected daily. Stud B exhibited more positive sperm characteristics and a greater relative abundance of Proteobacteria than Stud A. Sperm motility decreased over time, with day one having increased bacterial richness and evenness compared to all other days. These results led to the development of the research objectives for Section 4, which were to characterize the bacterial communities in different boar reproductive tissues and investigate the expression of toll-like receptors (TLRs) in these tissues. Boar reproductive tracts were collected at different age points (pre-pubertal and pubertal), and samples were collected for the testis, epididymis, prostate, seminal vesicle, bulbourethral gland, bladder, and preputial diverticulum. The four main phyla for both pre-pubertal and pubertal boars were Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria. A few genera including Ruminococcus, Blautia, Bacteroides, Facklamia, and Oscillospria differed in relative abundance between the preputial diverticulum and the bulbourethral gland, epididymis, prostate, seminal vesicle, and testis in the prepubertal boars. In the pubertal boars, the relative abundance of many genera (Porphyromonas, Geobacillus, Caldicellulospiruptor, Peptoniphilus, and Facklamia) differed by tissue type. Further, TLR2 mRNAs had greater expression in the testis compared to the epididymis, prostate, and seminal vesicles in prepubertal boars. Based on these findings, there is a diverse community of bacteria residing in the boar semen microbiome and associated reproductive tissues. Additionally, certain bacteria can influence sperm cell longevity and can potentially interact with reproductive tissues using TLRs.
The Brain and Beyond: Maternal and Fetal Targets of Chronic Alcohol Exposure in Pregnancy
(2023-12-04) Lunde, Emilie Raine; Heaps, Cristine L; Golding, Michael C; Johnson, Gregory A; Miranda, Rajesh C
Fetal alcohol spectrum disorders (FASD) persists as significant a public health threat partly due to enmeshment of drinking culture in modern society and partly because of the inherent complexity of alcohol-mediated pathogenesis. Discernment of FASD pathogenesis remains warranted because of the persistence of this threat coupled with extremely limited treatment options for affected patients. In the following studies (Chapters 2 & 3) we used classic approaches to describe a potential mechanism for alcohol-mediated pathogenesis in an atypical focal point of FASD investigation: the maternal uterine artery. The latter part of this work (Chapters 5 & 6) applied advanced technologies (HPLC, next-gen RNA sequencing) to identify new foci in a classic FASD target: the fetal brain. All studies were completed using a well characterized in vivo model of chronic binge prenatal alcohol exposure with clinical relevance. In the uterine artery, alcohol impaired the myogenic response and endothelial-mediated vasodilation, and dysregulation of the nitric oxide (NO) pathway and the enzyme responsible for NO synthesis (eNOS) were presented as susceptible candidates for this dysfunction. Brain studies described here bolster support for pursuing investigation of how excitatory amino acid imbalances influence neurotoxicity, expressly in the developing cerebellum and hippocampus. Transcriptome analysis also identified new hippocampal genes and canonical pathways of investigational interest based on their previous linkage to alcohol and FASD-adjacent pathology but were not tied to FASD contextually to FASD until now. Ultimately, we affirmed that alcohol use during pregnancy is unsafe and poses significant health risks not only to fetal development but to maternal physiology essential for sustaining this development.

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