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Exploring the Considerations of School Zone Speed Control in Traffic Signal Timing
No full textSchool zone speed control is a crucial safety intervention that assists in slowing down traffic and warning drivers to pay more attention to vulnerable road users. This restriction may result in impacts on arterial traffic operations, including speed reduction and potentially additional stops at intersections. Among the various measures implemented for school zone speed control, the potential of utilizing traffic signal timing strategies to influence driver behavior and maintain reduced speeds in school zones remains largely unexplored in the literature. This study aims to develop a data-driven methodology based on probe vehicle trajectory data to explore and quantify the influence of school zone speed control, which can then identify the needs and considerations to adjust traffic signal timing. Traffic signal timing performance is generally evaluated using measures such as arterial average speed, the number of stops, and delay on minor movements to understand how traffic flows through the corridor. Subjects regarding whether school zone speed control can impact corridor signal coordination are investigated in this study through the dissection of probe vehicle trajectories within several school zones in the Reno-Sparks region in Nevada. WaySync software is used to compute arterial traffic signal performance measurements. Descriptive statistical analysis and t-tests have been conducted to understand the statistical significance of the school zone speed control flasher on these performance measurements. The findings indicate and quantify the influence on corridor signal coordination resulting from school zone speed control. In the case study, reductions are observed in corridor signal timing performance during the periods when school zone speed control is in effect. Further analysis focuses on driver behavior in school zones, specifically examining speed and acceleration profiles in response to downstream green and yellow signals. The findings reveal that drivers tend to accelerate when encountering a green or yellow light, potentially undermining the safety benefits of reduced speed limits in school zones. By integrating the impact of school zone speed control on both signal timing performance and driver behavior, this research provides actionable insights for optimizing traffic signal timing strategies
Towards Enhanced Earthquake Resilience: Linking Early Warning Systems, Ground Motion Prediction, and Stress Field Analysis
No full textEarthquakes pose a significant threat to life and infrastructure, making it essential to improve both our understanding and preparedness for seismic events. This study investigates several interconnected aspects of earthquake science to enhance our ability to forecast and mitigate the impacts of these natural disasters. We explore the development of Earthquake Early Warning (EEW) systems, which provide real-time alerts to minimize damage and save lives. While EEW systems like ShakeAlert, the system in operation along the west coast of the US, show great promise, challenges remain, particularly in accurately predicting ground motion and event characteristics in complex tectonic settings. To address this, we examine how fault complexity affects ground motion predictions, emphasizing that realistic fault geometries and fault-zone properties can significantly influence seismic behavior. The study also analyzes the local stress field in tectonically active regions to better understand earthquake dynamics and faulting patterns. Using data from focal mechanism catalogs, we investigate stress orientations and their role in earthquake triggering and fault reactivation. The findings highlight the importance of accurately modeling stress conditions and fault structures to refine seismic hazard assessments. By combining advancements in early warning systems, ground motion prediction, and stress analysis, this research contributes to more effective earthquake preparedness strategies, improving resilience in earthquake-prone regions
Post-translational phosphorylation dynamics in Arabidopsis and Physcomitrella
No full textPhosphorylation is the most abundant post-translational modification that involves the chemical addition of a phosphate group onto serine, threonine, or tyrosine residues of substrate proteins. Phosphorylation is utilized to regulate protein activity, stability, or localization to respond to cellular needs. This dissertation starts in Chapter Two by discussing the phospho-regulation of the Arabidopsis plant cellulose synthase complex and cellulose synthase-like proteins. Chapter Three discusses protein-protein complex dynamics in the model moss plant Physcomitrella patens. This chapter demonstrates that Physcomitrella convergently evolved to contain hetero-oligomeric cellulose synthase complexes similar to land plants like Arabidopsis. Chapter Four investigates how the loss-of-function of a secretory pathway protein can suppress the near-sterile phenotype of a calcium-dependent protein kinase in Arabidopsis pollen, providing the first genetic connection between a calcium kinase and the secretory pathway. Lastly, Chapter Five utilizes quantitative phospho-proteomics to identify two proteins with heat-stress-dependent phosphorylation sites with implications on pollen fitness. To conclude, this dissertation describes a phosphorylation-dependent link between the topics covered in each chapter and a concluding perspective on how this work could contribute to the future of plant phosphorylation research
Movement, Demography, and Population Dynamics of a Large Herbivore: Experimental Evaluation of Interspecific Competition
No full textMany aspects of the ecology of large, herbivorous mammals are influenced by density-dependent processes where the observed patterns in movement, demographic, and population dynamics are closely related to the size of the population in relation to the number of animals that can be supported by the environment. Dynamics of these populations are influenced by negative feedback loops that stem from the closeness of the population to the carrying capacity of the environment. Populations becomes more susceptible to stochastic fluctuations in the environment when the population is close to carrying capacity. Competitive interactions leading to resource limitation, resulting in a lowering of carrying capacity, is a mechanism with the potential to regulate populations of density-dependent species. Nevertheless, cause and effect relationship between competition and population regulation has not been clearly demonstrated for free-ranging large herbivores. Clearly defining these relationships requires experimental manipulations that are difficult to implement for these species. Moreover, interspecific competition between mule deer (Odocoileus hemionus) and North American elk (Cervus candandensis) has been postulated as one explanation for declines in mule deer populations across much of their range. The primary objective of my dissertation research was focused on using an experimental reduction of a population of elk that was sympatric with a mule deer population to test hypotheses related to whether competition with elk influences movements, demographics, and population dynamics of mule deer. Further, my research is an evaluation of the effectiveness of elk reduction as a management strategy to conserve declining populations of mule deer. The results of my research indicate that competition with elk influences selection of resources by mule deer. Mule deer avoided areas with high density of elk in the late spring and early summer. Patterns of avoidance following reduction of elk were lower during late spring than prior to the elk reduction, but during early summer avoidance of elk did not differ between those time periods. These effects on the movement patterns by mule deer did not translate into an increase in demographic or population growth rates following the reduction of elk. These results suggest that competition with elk was not regulating this population of mule deer and indicates that reduction of elk populations may not be an effective tool for management of mule deer populations. The primary drivers of population dynamics for this population of mule deer was a negative effect of winter severity on survival of adult females and a positive effect of body size at birth for survival of juveniles. These results highlight the importance of nutrition for population dynamics of mule deer. Adult mule deer that are on a higher plane of nutrition are more buffered against the effects of harsh winters. Further, adult females on a higher plane of nutrition were more likely to produce large juveniles with high probability of survival. These findings suggest that conservation of mule deer is best served by placing emphasis on habitat improvements that benefit the nutritional condition of the individuals in the population and may be a more effective tool for management than reducing elk populations
ELECTRONIC NICOTINE PRODUCTS AS A HARM REDUCTION INTERVENTION FOR CIGARETTE CESSATION AMONG PEOPLE WITH SUBSTANCE USE DISORDERS (PWSUDs)
No full textBackgroundThe prevalence of cigarette smoking in the US has continued to decline over the past two decades. However, the prevalence of cigarette smoking remains high among certain population groups, including people with substance use disorders (PWSUDs), compared to estimates in populations without substance use disorders. Due to the high rates of smoking among PWSUDs, they are disproportionately affected by tobacco-related illnesses compared to the general population. Therefore, identifying interventions that can reduce the harm of tobacco use and promoting the health of this population has the potential to save lives and promote health in the wider US population.
Purpose
The aims of my dissertation include the following: 1. to compare the uptake of cigarette smoking cessation aids (e.g., Food and Drug Administration (FDA)-approved cessation products or e-cigarettes) among US adults (18+ years) with substance use problems (PWSUPs) who currently smoke to people without substance use problems (SUPs) who currently smoke cigarettes in a nationally representative US sample; 2. to examine the effect of e-cigarette use with instructions as a switching tool on daily cigarette consumption among US adults (21+ years) with substance use disorders; and 3. to understand the experience of US adults (21+ years) with substance use disorders regarding the use of e-cigarettes for switching away from cigarettes and its acceptance within their social network following a brief intervention using e-cigarettes to switch to cigarettes.
Methods
In the first paper, I used a cross-sectional design with a nationally representative sample of US adults to investigate the differences in past year uptake of FDA-approved cessation aids (i.e., nicotine replacement therapies (NRTs), cessation medications (i.e., varenicline, bupropion)), e-cigarettes for cigarette cessation, and e-cigarettes for cigarette reduction among individuals with substance use problems compared to those without. The study sample was obtained from the US Population Assessment of Tobacco and Health (PATH) Study Wave 6, which was collected in 2021. Weighted multivariable logistic regression models were used to identify the uptake of cessation aids and e-cigarettes for cessation and reduction between individuals with high-severity SUPs and those without SUPs. In the second paper, I used an intensive longitudinal design with a sample of US adults enrolled in outpatient substance use treatment. The population provided daily diaries of number of cigarettes smoked per day (CPD) over a baseline period (days 1-7), and then received e-cigarette devices, guided instructions on how to switch from cigarettes to e-cigarettes, and four pods of tobacco-flavored nicotine e-liquids. Participants then provided daily records on CPD and daily e-cigarette puff times over a period of two weeks. Linear fixed effect models were used to estimate the change in CPD by e-cigarette puff times. For the third paper, I conducted in-depth qualitative interviews with participants who completed a two-week period of e-cigarette use for switching. I used an inductive approach to explore themes relating to the experience of switching to e-cigarettes on nicotine cravings, social relationships, and fit with substance use treatment among adults in outpatient treatment for substance use disorders.
Results
Study One
My results showed that among adults who smoke cigarettes, a higher proportion of those with high SUP severity used NRTs, cessation medications, and e-cigarettes for cigarette cessation, respectively (12.3%, 8.4%, 15.7%), compared to those with no/low SUP severity (9.8%, 6.0%, 8.9%). I also found that respondents with high SUPs had 63% (95% CI:1.16-2.29) higher odds of using e-cigarettes for cessation than those without SUPs.
Study Two
My study sample comprised 25 eligible adults who had a median age of 40 years. Following the switch to e-cigarettes on day-8, the number of cigarettes smoked per day (CPD) reduced on average by 21 cigarettes (β: -20.58; 95% CI: -22.10, -19.07). For every one time a participant used e-cigarettes above their personal average, they smoked 0.12 fewer cigarettes (95% CI: -0.20, -0.04), and as the days progressed following e-cigarette use, daily CPD decreased on average (β: -0.20; 95% CI: -0.32, -0.08).
Study Three
The study sample comprised 30 adults in outpatient treatment for substance use disorders. I identified six main lines of inquiry from descriptions participants provided about their experience using e-cigarettes to switch from cigarettes with multiple themes within each line of inquiry, namely: 1. Facilitators and barriers during switching experience; 2. Moments of persistent craving and smoking lapses; 3. Strategies and adaptation among PWSUDs using e-cigarettes to switch away from cigarettes; 4. Navigating e-cigarette use as a switching tool during substance use treatment; 5. Intentions on future e-cigarette use after switching. A common facilitator was the convenience of e-cigarettes based on their sensory and physical attributes, which simulate cigarettes. A common barrier was lack of satisfaction from e-cigarettes. Participants also indicated perceived health benefits, social opportunities were facilitators for switching; and moments of persistent cravings occurred in the mornings after waking, after meals, and during stressful situations. Notably, participants described tapering down their cigarette use rather than making an abrupt switch, as a more practical strategy. There were mixed intentions on whether to continue using e-cigarettes after quitting cigarettes or to quit e-cigarettes as well.
Conclusions
Research on smoking cessation among individuals with substance use disorders is crucial for saving lives and improving health outcomes in the US, as it has the potential to impact more than half of the 48.5 million US adults affected by SUDs who smoke cigarettes. This thesis contributes to the broader scientific literature by demonstrating that individuals with SUDs have higher odds of using e-cigarettes for cigarette cessation and reduction than those without SUDs. The research also suggests that nicotine e-cigarettes could be effective for reducing cigarette consumption when interpreted alongside other studies, with these findings extending to populations with problematic psychoactive substance use outside of residential treatment settings, using standardized devices with guided instructions.
Importantly, I found that the experience of using e-cigarettes as a smoking harm reduction tool—and switching from cigarettes to e-cigarettes—is multifaceted, with multiple individual-level factors (e.g., perceived satisfaction, motivation from health benefits) and social factors (e.g., familial or peer support) contributing to the potential success of cessation or reduction. Overall, these findings suggest that guided e-cigarette use may be an acceptable, effective, and practical cessation intervention for adults with SUDs who are interested in quitting or reducing cigarette smoking. Future studies can explore how evidence-based counseling and behavioral management strategies might be deployed to support cessation with e-cigarettes. Policy measures can also be developed to integrate e-cigarettes as smoking harm reduction tools for adults in SUD treatment who are motivated and interested in using them to quit or reduce cigarette smoking
Border-Lines, Volume X
No full textBorder-Lines is an interdisciplinary and intersectional academic journal dedicated to the dissemination of research on Chicana/o-Latina/o cultural, political and social issues. Border-Lines is a refereed journal that seeks to publish scholarly articles drawn from a variety of disciplines such as anthropology, education, geography, human health, literary and cultural studies, political science, social work and sociology
Advancing Urban Transportation System Operational Performance Evaluation Using Probe Vehicle Telematics Data
No full textEfficient urban transportation system operational performance evaluation closely relies on continuous and high-quality traffic data collection. Traditionally, traffic data is collected from manual labor counts or static detectors temporarily or permanently installed at fixed locations on urban roadways. However, there are several limitations of using traditional data collection methods for transportation system operational performance evaluation. Firstly, the manual labor count or temporary detector installations is cost-ineffective in terms of labor costs and limited spatial and temporal data coverage. Secondly, the number of permanent detector installations are limited in roadway networks and can only collect point-level data rather than reflecting a complete and detailed picture of vehicle operations. Thirdly, malfunctioning detectors can generate missing or bad-quality data, which significantly deteriorates the accuracy and reliability of operational performance evaluation. The emergence of probe vehicle telematics data (PVTD) has great potential to supplement the existing data sources to facilitate operational performance evaluation by generating large-scale and prolific vehicle trajectory data which contains high-resolution spatial, temporal, and operational information of individual vehicles. Therefore, this dissertation explores and presents three innovative applications of using PVTD to advance operational performance evaluation for different roadway facilities, including freeways and arterials.For freeways, this dissertation utilizes PVTD to verify the accuracy of speed measured by freeway detectors and compare the sensitivity of detecting congestion formation and dissipation between vehicle trajectory speeds and detector speeds on basic freeway segments.
For arterials, this first application is focused on utilizing PVTD as an alternative tool to facilitate the use of performance evaluation methodology of urban street facilities in the Highway Capacity Manual (HCM). The second application is to propose an easy-to-use trajectory-based performance measure, Arterial Through Percent Arrivals on Red (ATPAoR), and investigates the relationship between ATPAoR and Percent Arrivals on Red (PAoR) in the Automated Traffic Signal Performance Measures (ATSPM) for arterial signal coordination performance evaluation.
The lessons learnt from three applications aim to assist practitioners in better understanding the use of PVTD to supplement the existing data sources, performance measures, and performance evaluation methodologies to conduct urban transportation system operational performance evaluation in an efficient manner
How Long Is Enough? Floodplain Soil Recovery and the Effects of Intensive Grazing in Northern Nevada Lake Shores
No full textUnderstanding soil health is critical to assess effects of ecosystem disturbance. It is important to understand recovery rates of disturbed soils to better forecast soil-driven ecosystem process recovery. Nutrient cycling , water retention and distribution, and plant growth are tied to soil health. This study examines soil characteristic differences between paired wet meadow sites under different historic and current grazing regimes by comparing soil conditions of the surface horizons. Land use history, vegetative community, and vegetation cover were regressed with soil health indicators to determine their effects on soil structure and chemical makeup. Vegetation cover was found to be significantly (p<0.05) correlated with soil penetration resistance, water infiltration, aggregate stability, and bulk density, while community was found to be correlated with pH. Land use history affects aboveground vegetation. These findings indicate that the effects of land use history have not yet overshadowed the effects of vegetation and community because the differences between sites were most correlated with immediate effects of grazing, while the differences between communities described underlying soil characteristics. Soil structure and chemical makeup function as a lagging indicator of grazing, changing after defoliation