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Effects of Information on Markets and Behavioral Economics
No full textThe dissertation systematically analyzed the effect of information in various aspects of economic and social systems. Specifically, it focused on tax information on food markets, market information on strategic decisions, and social information on decision-making in economic games.
The first essay investigated the effects of sugar-sweetened beverages (SSBs) tax in the city of Berkeley and Philadelphia. We constructed a difference-in-difference (DID) model to examine the effects of the tax on the consumption and retail prices using Nielsen retail scanner data. The finding suggested that SSBs tax had no significant effect on consumption and prices in Berkeley, while the tax significantly increased the price and decreased the consumption of SSBs in Philadelphia. The opposite results in the city of Berkeley and Philadelphia suggested that geographical and social demographic characteristics would affect the effectiveness of a policy, and SSBs tax works better in large territories with diverse population.
The second essay analyzed transaction data from eBay to explore sellers��� strategies in online auctions. We focused on three selling formats on eBay: fixed-price listings, auctions, and BIN(Buy it Now)-auctions, comparing new products and outdated products for electronics. A probit model and Heckman correction procedure were applied to examine the effect of seller���s selling strategy on transaction success rate, final transaction price, and the seller���s revenue. Results indicate that fixed-price listings are preferred. Selling formats significantly influence outcomes for new products, while they show minimal effects for outdated ones. Moreover, we identify key price determinants for each listing format. The BIN price is crucial for fixed-price listings. For auctions and BIN-auctions, the duration and starting price emerge as key factors influencing transaction outcomes.
The third essay explores cooperation in social dilemmas, focusing on the impact of inequality on cooperation in public goods dilemmas. Our study evaluate cooperation in metrics of efficiency (total contribution) and equality (contribution from the wealthy). Incorporating 32 articles with 50 experiments, we found that heterogeneous endowments do not significantly affect equality, but it negatively impact efficiency, leading to decreased total contributions. Overall, heterogeneous endowments detrimentally affect cooperation. Furthermore, moderator analyses show that iteration numbers could negatively moderate the relationship between heterogeneous endowments and cooperation, indicating a greater detrimental effect on cooperation in public goods games with more iterations
Common Operating Picture Enhancement for Cyber-Physcial Data and Under Contingencies
No full textThe power grid is the foundation of contemporary society's infrastructure, so it is crucial to take strong cybersecurity precautions to guard against potential disruptions that could have a significant impact on the stability and functionality of society. The power grid is particularly vulnerable to new cyber threats that pose a growing threat to its resilience.
This research explores the crucial role of common operating pictures in bolstering the cybersecurity of critical infrastructure with easily understandable data. The primary approach to depicting the common operating picture involves the utilization of Graphical User Interfaces (GUIs), which serve as digital platforms enabling operators to engage with physical equipment via visual graphics and graphical icons. The study investigates the Cyber-Physical Resilient Energy Systems Energy Management System (CYPRES EMS) and places a significant emphasis on Cyber-Physical Situational Awareness (CyPSA).
Furthermore, the study illuminates the advantages of integrating a risk matrix graph within and environment called CYPSA live environment. This integration utilizes data on common vulnerabilities and exposures sourced from the National Vulnerabilities Database (NVD). The inclusion of the risk matrix graph provides heightened clarity on the intricacies of the risk landscape, equipping users with discerning options for informed decision-making.
This study builds upon established analytical methodologies, such as attack tree graphs and a method called Failure Modes, Effects, and Criticality Analysis (FMECA), to comprehensively identify and address potential risks and threats to the system.
In conclusion, the results underscore the potential insights derived from combining these technologies, offering a more effective means to protect critical infrastructure from evolving cyber threats and vulnerabilities. The findings contribute to the growing body of knowledge aimed at bolstering cybersecurity measures for vital systems
Musculoskeletal Pain and Preferred Pain Management Strategies Among Dental Professionals and Dental Students
No full textDental professionals and students are predisposed to musculoskeletal pain. However, few primary research studies have investigated musculoskeletal pain and pain management strategies among US-based dental professionals and students. Examining musculoskeletal pain and pain management experiences among dental professionals and students may provide inform opportunities to prevent musculoskeletal pain, thus improving their performance and retention in the workforce.
The primary purposes of this dissertation study were to: (1) understand issues that predispose dental professionals (workers and students) to musculoskeletal pain; (2) explain the associations between musculoskeletal pain and the strategies used for pain management; and (3) identify potentially harmful postures that could cause musculoskeletal pain among dental professionals by performing a concordance analysis of traditional ergonomic evaluation versus computer-based motion capture system assessment of select dental procedures.
The first study, a scoping review that examined musculoskeletal pain and pain management experiences of dental professionals and students, found musculoskeletal pain prevalence between 46% and 92.2%. The neck, wrist/hands, shoulders, and back had the most self-reported pain, while complementary alternative medicine (CAM) was the commonly used pain management strategy.
The second study administered internet-based surveys to dental professionals and dental students. Of the 1,510 study participants, 68.2% self-reported musculoskeletal pain. About 79.2% dental students, 70.6% dental assistants and hygienists, 65.7% dentists, and 60.4% dental therapists reported musculoskeletal pain. CAM (61.3%) and medication (49.7%) were the commonly used pain management strategies.
The third study, a concordance analysis of traditional (Rapid Entire Body Assessment, Rapid Upper Limb Assessment, and Strain Index) and computer-based ergonomic assessment (Humantech motion capture system) on non-participatory observation data, assessed the risk of developing musculoskeletal disorders among dental hygienists. Findings showed slight-to-fair agreement between traditional and computer-based ergonomic assessments. Findings suggest further refinement and testing of digital ergonomic assessment technologies are needed for the dental professions.
Taken together, this dissertation highlights the magnitude of musculoskeletal pain among dental professionals and students in the US and their preferences in strategies to manage pain. It illuminates factors associated with pain, the need for ergonomic assessment, and the potential for digital ergonomic assessment to detect harmful positions, which may cause or exacerbate musculoskeletal pain
The Formulation of a Consequence-Informed Methodology for the Design of Physical Protection Systems at Advanced Commercial Reactor Facilities
No full textThe survivability of the domestic nuclear power industry depends on the cost-competitiveness of safe and secure nuclear power generation. Advanced reactor design concepts aim to have increased safety margins over traditional large Light Water Reactors (LWRs). With increased safety margins comes the potential for a corresponding decrease in off-site risk to the general public from a hypothetical release of radioactivity caused by an accident or deliberate sabotage. Without sacrificing safety or security, advanced reactor designers may be able to achieve capital and operational cost improvements over current LWRs, in part, by designing less burdensome Physical Protection Systems (PPS), and by placing response forces off-site. To accommodate these developments, the U. S. Nuclear Regulatory Commission (NRC) is drafting new regulations for physical security when licensing through the current 10 CFR 50 or 52, along with drafting an entirely new licensing framework, 10 CFR 53.
This dissertation presents a novel technology-inclusive consequence-informed methodology for the selection of the optimal licensing path for the design of Physical Protection Systems (PPS) at advanced fixed-site commercial nuclear power facilities, and applies the methodology to a hypothetical reactor facility containing a microreactor design. The resulting methodology incorporates current and proposed regulatory limits for off-site dose consequence to the general public to guide the licensing applicant in choosing the licensing pathway which best suits their desired financial costs and PPS design characteristics. For the methodology application to a microreactor site, newly allowed PPS characteristics in proposed NRC draft regulations were incorporated into the ultimate PPS design. MELCOR code analysis of potential adversary-executed sabotage actions, and off-site doses predicted by the MACCS code, were coupled to determine off-site consequence of the facility while PathTrace and SCRIBE 3D were used to develop a PPS model of the facility for effectiveness testing. The resulting PPS was compared to a PPS at the same facility designed following traditional security licensing requirements in 10 CFR 73. Results of the comparison demonstrated an increase in necessary capital costs for the construction of a facility with enough delay to accommodate a 30-minute off-site response force response time. However, the reduction in security force staffing showed the potential for significant savings in operational staffing
The Coordination Between Peptidoglycan Hydrolases and Synthases in Myxococcus xanthus
No full textPeptidoglycan (PG) defines cell shape and protects bacteria against osmotic stress. The growth and integrity of PG require coordinated actions between synthases that insert new PG strands and hydrolases that generate openings to allow the insertion. However, the mechanisms of their coordination remain elusive. Here, I show that moenomycin that inhibits a family of PG synthases known as Class-A penicillin-binding proteins (aPBPs), triggers cell lysis despite aPBPs being non- essential for cell growth. We demonstrate that inhibited PBP1a2, an aPBP, accelerates the degradation of cell poles by DacB, a hydrolytic PG peptidase, in the bacterium Myxococcus xanthus. Moenomycin reduces the mobility of DacB molecules through PBP1a2, potentially promoting the binding between DacB and PG. Conversely, DacB also regulates the distribution and dynamics of aPBPs. These findings reveal the lethal action of moenomycin and suggest that disrupting the coordination between PG synthases and hydrolases could be more lethal than eliminating individual enzymes. The process of sporulation provides a unique scenario in M. xanthus to study PG regulation. Sporulation is the process by which spherical spores are formed in M. xanthus, from its regular rod shape in vegetative cells. Surprisingly, in our model organism, there is complete degradation of PG during this rod-to-sphere transition during chemically induced sporulation as well as during the formation of fruiting bodies. During this process, there is an upregulation of PG hydrolases, enzymes which are usually redundant in bacteria. Lytic transglycosylases, which cleave the glycan backbone, are important for the process of sporulation, and our results identified MXAN_3363 (LtgA) and MXAN_4034 (LtgB) as important for the process of sporulation, the former for glycerol induced sporulation and the latter for both sporulation pathways
Investigating Chronic Enterocolitis in Rhesus Macaques (Macaca mulatta) as a Natural Model for Post-Infectious Irritable Bowel Syndrome and the Role of Campylobacter spp. in Disease Development
No full textCampylobacter jejuni and C. coli represent the leading causes of bacterial gastroenteritis in humans worldwide and up to 20% of infections will result in post-infectious irritable bowel syndrome (PI-IBS). Investigations into the pathogenesis of PI-IBS have been hampered by lack of a complete animal model for the syndrome. We aimed to investigate the chronic diarrhea syndrome known as chronic enterocolitis (CE) in rhesus macaques (Macaca mulatta), and the potential contribution of Campylobacter infection to this syndrome, as a naturally occurring model of PI-IBS. We characterized subjective and objective variables in sections of the lower intestinal tract in 16 healthy rhesus macaques and compared these results to a cohort of 37 animals euthanized for CE. Similar to PI-IBS, animals with CE had elevated total leukocyte populations in the large intestine and significantly increased intraepithelial CD3+ T cells in the colon and rectum. Unlike PI-IBS, neutrophils were increased in CE and enteroendocrine cells, enterochromaffin cells, and mast cells displayed no differences between study groups. We then utilized culture, qPCR, and whole genome sequencing (WGS) to characterize the Campylobacter sp. circulating in the study colony. Culture and WGS of 275 samples yielded a non-clonal population of 103 C. coli and 8 C. jejuni isolates, each containing genes for all three subunits of cytolethal distending toxin. Certain MLSTs were found only in animals with intestinal disease and some only in healthy animals. Antimicrobial resistance patterns were similar between these isolates and human reports. qPCR detected a higher prevalence of both bacteria than culture, the quantity of bacteria was significantly higher in animals with intestinal disease, and nearly 1/3 of animals were positive for both C. jejuni and C. coli. Using generalized linear mixed modeling, the only significant risk factor for the presence of Campylobacter sp. or intestinal disease was young age. Ultimately, we added to the understanding of CE, identifying areas where the syndrome overlaps with PI-IBS and areas that warrant further investigation, and advanced our knowledge of Campylobacter sp. circulating in rhesus macaques, allowing honing of future studies to investigate a causal link between the bacteria and CE as exists in PI-IBS
Direct Synthesis of Dimethyl Carbonate from Carbon Dioxide and Methanol, Investigating the Effect of Reaction Conditions and Dehydrating Agents
No full textDimethyl carbonate (DMC) is attracting attention lately because of its environmentally friendly characteristics as it is known to be a non-toxic, non-corrosive, and biodegradable material. DMC direct synthesis presents an environmentally friendly approach as it utilizes carbon dioxide (CO2) and does not use hazardous materials as in other processes. Despite its potential for CO2 fixation, several challenges restrict methanol conversion to DMC to around 1%, primarily due to water formation favoring DMC hydrolysis. Therefore, solution such as the use of dehydrating agents and a reactive distillation have been proposed. Different dehydrating agents have been experimentally studied such as zeolite 3A, zeolite 4A, and ZSM-5. Before assessing dehydrating agents, various experiments were conducted to optimize reaction conditions, revealing that the highest DMC yield occurs at 110��C, 30 bar pressure, 200 mg catalyst dosage, and a 2-hour run duration. Tested dehydrating agents slightly increased DMC % yield; however, they failed to shift the equilibrium adequately. Consequently, reactive distillation is seen as a promising alternative, necessitating a kinetic model for accurate prediction. A low-pressure kinetic model was developed within this work, showing good agreement with experimental data (MAPE: 17%). After that, a CO2Fix metric was used to study the potential of the direct synthesis method for CO2 fixation. Based on the model, it was concluded that 2-CP exhibits the highest CO2Fix potential with a 3.68 CO2Fix. Moreover, it was determined that compounds with 6-membered nitrogen heteroaromatic ring such as benzonitrile, acetonitrile, and shows higher CO2Fix potential compared to other dehydrating agents
Assessing Orthodontic Compliance with Tailored vs Generic Reminders
No full textThe purpose of this study is to evaluate the effect of daily automated tailored reminders compared to generic ones on the improvement of oral hygiene compliance.
A blinded, prospective, randomized controlled trial was designed to evaluate the effects of the content of reminders. Subjects were recruited from patients undergoing orthodontic treatment at the Texas A&M University College of Dentistry, Department of Orthodontics and were treated with fixed full appliances in both arches. Subjects were randomly assigned to either a tailored text message group or a generic text message group. There were 68 subjects recruited who were 12 to 17 years of age. Oral hygiene was measured at the beginning of the study and again 8 weeks later.
The generic reminder group had significant improvements in oral hygiene compliance from timepoint 1 to timepoint 2. Decreases from T1 to T2 were 1.20 to 0.59, 1.88 to 1.10, and 3.56 to 2.90 for bleeding index (BI), gingival index (GI), and plaque index (PI), respectively (p<0.001). The tailored reminder group had significant improvements in oral hygiene compliance from timepoint 1 to timepoint 2 as well. Decreases from T1 to T2 were 1.33 to 0.58, 2.02 to 1.12, and 3.75 to 2.81 for bleeding index (BI), gingival index (GI), and plaque index (PI), respectively (p<0.001). All initial values in the tailored group and total decreases for all three periodontal tests were higher than in the generic group but were not statistically significant.
Tailored daily reminders are not more effective at improving oral hygiene compliance than generic daily reminders
Computational Fluid Dynamics Analysis of the Blockage Accident in Wire-Wrapped Fuel Rod Bundles
No full textThe purpose for reducing CO2 emissions and enhancing the safety of nuclear reactors have led to increased interest in Liquid Metal Fast Reactors (LMFRs). These reactors offer high power density, low-pressure operation, and the ability to breed fissile material. However, LMFR fuel assemblies, comprising fuel pins enclosed in hexagonal ducts with wire-wrapped spacers, are susceptible to coolant flow blockages due to debris buildup, potentially leading to reduced heat transfer and fuel cladding damage. This PhD dissertation aims to conduct a comprehensive computational fluid dynamics (CFD) analysis of blockage accidents in wire-wrapped fuel rod bundles. The objectives include the preparation and validation of CFD models for both nominal (unblocked) conditions and various blockage scenarios, considering solid and porous blockages. Conjugate heat transfer modeling is also incorporated to simulate the cladding temperature. The proposed research activities encompass analyzing fluid flow behavior, pressure drop, velocity, turbulent structures, and temperature profiles for the different blockage configurations. Experimental data from wire-wrapped test facilities is used to validate the CFD models. These facilities have provided high-fidelity data of velocity and pressure drop for transition and turbulent flow regimes at nominal conditions, as well as for blockage scenarios with solid and porous obstructions. The CFD methodology involves solving the incompressible Navier-Stokes equations with the Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) methods. The results demonstrate the accuracy of the proposed methodology in predicting friction factors and velocity profiles in both unblocked and blocked bundles after the comparison with the experimental data. The findings reveal that the presence of blockages in wire-wrapped fuel rod bundles significantly impact the thermal-hydraulic performance of LMFRs. The analyses show that solid blockages cause an increase in pressure drop and a decrease in velocity, while porous blockages have a lesser impact. The turbulence analysis reveals that the blockages lead to the formation of vortices and eddies, which can further impact the flow behavior and heat transfer. This research yields valuable insights into blockage accidents and contribute to gain more reliability in the use of CFD models for safety assessments of LMFRs
Structural Analysis of Irregular Cracking in Continuously Reinforced Concrete Pavements
No full textThis research study explores the analysis of irregular cracking in continuously reinforced concrete pavements (CRC) using a synergized approach of analytical and numerical methods. A Python script was developed to execute linearized finite difference analysis, assessing temperature and moisture profiles to compute environmental stresses, including thermal and shrinkage effects. This script integrates these stresses with user inputs to run finite element analysis using the ABAQUS solver. Concurrently, the study provides a revision of the AASHTO crack spacing formula presented in the Mechanistic-Empirical Pavement Design Guide (MEPDG) for CRC pavements. The modified formula addresses the limitations of the previous version, providing insight into the depth of crack initiation. The study uncovers several key insights into early-age cracking in continuously reinforced concrete pavements including -but not limited to- variations in temperature and moisture profiles across different locations and seasons that significantly impact the cracking mechanism. Longitudinal steel cover is found to be a critical factor, with smaller cover increasing the likelihood of top-down. The study also reveals that while active cracking control is effective in determining crack locations, its efficiency is compromised when the bonding to the underlying layer is weak. Ultimately, the high bonding strength between PCC slabs and the underlying layer not only increases the possibility of bottom-up cracking but also decreases crack spacing