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PLANT METABOLISM OF POLYCHLORINATED BIPHENYLS (PCBs) BY ARABIDOPSIS THALIANA: IMPLICATIONS FOR BIOREMEDIATION OF PCBs BY PLANTS
Full text linkPlants absorb, accumulate, and metabolize persistent organic pollutants from the environment. Polychlorinated biphenyls (PCBs) are widespread toxic pollutants that pose a severe threat to humans and the environment. PCBs were banned in 1979 because of their toxicity and persistence in the environment. Plant safeners are compounds that are used to protect crops against the action of herbicides. Safeners are believed to act through the expression of detoxifying enzymes, like glutathione S-transferases. The main objective of this study is to test the potential of plant safeners that enhance the metabolism of PCBs in the model plant Arabidopsis thaliana. The first specific aim of this study was to determine the transcriptomic response of A. thaliana exposed to selected PCBs, i.e., 2,5-dichlorobiphenyl (2,5-DCB) and 4’-hydroxy-2,5-dichlorobiphenyl (4’-OH-2,5-DCB). Transcriptomic analysis revealed that both 2,5-DCB and 4’-OH-2,5-DCB induced the expression of genes potentially involved in the xenobiotic metabolism, including peroxidases and glutathione S-transferases, as well as genes involved in lignin biosynthesis, particularly the phenylpropanoid pathway. Using Fourier-transformed infrared (FTIR) spectroscopy confirmed that these compounds increased the lignin content in exposed plants. The second specific aim was to identify plant safeners that are effective at protecting the plants against the harmful effects of 3,3'-dichlorobiphenyl (3,3'-DCB). Using toxicity testing based on the germination rate and biomass growth, we observed that one safener, fenclorim, was capable of protecting Arabidopsis plants against the inhibitory effect of 3,3'-DCB. In specific aim three, gene expression analysis showed that the presence of fenclorim stimulated the expression of several genes potentially involved in the metabolism of 3,3'-DCB, including glutathione S-transferases and cytochrome P-450, explaining the protective effect of fenclorim on exposed plants. These results suggest that fenclorim can enhance the plant’s capability to metabolize 3,3’-DCB potentially making it a valuable tool for bioremediation efforts targeting environments contaminated with persistent organic pollutants. The study provides important insights into molecular mechanisms underlying plant response to chemical stress and the role of safeners in improving plant resilience. This suggests a promising approach for improving plant resilience and detoxification in environments contaminated with xenobiotic pollutants. Keywords: Arabidopsis thaliana, PCBs, RNA, RT-qPCR, safeners, fenclorim, lignin, RNA-sequencin
Expand Voting Access Reform: Automatic Voter Registration and Election Day as a Federal Holiday
Full text linkVoting is not just casting a vote; it also represents people having the freedom to choose what they like, to express to the present government, and to be representative, which is a fundamental stone to democracy. Freedom of speech and the right to act are deeply rooted in the Constitution, reflecting the core values of American democracy. In the Preamble for the Constitution, show how important liberty is to United States people: We the People of the United States, we secure the Blessings of Liberty to ourselves. Also, the First Amendment points out the freedom of speech that can’t be controlled by the government. Democracy is represented by the people.
Making elections more accessible and flexible can increase voter participation, which is crucial for a democratic country that values freedom and representation. Therefore, we must implement an expanded voting access reform. The 2020 presidential election achieved the highest voter turnout for any national election since 1900, with 66.7% of eligible voters participating (University of Florida Election Project, 2024). If we compare the 2016 United States voting-eligible population turnout rate, which is 60.12%, to 2024, which is 63.68%, it shows that with more and more flexible access to voting, people will be more engaged in voting (University of Florida Election Project, 2024). What we changed in 2020 is we expanded mail-in voting, or no-excuse absentee voting, due to the pandemic. We see the percentage of voters casting ballots by mail grew to 46 percent, more than doubling the fraction from 2016. Sixty percent of mail-in voters stated that it was “very likely” they would vote by mail again (MIT Election Data and Science Lab, 2023)
Managing Mental Health Calls for Service: An Evaluability Assessment of Co-Located Behavioral Health Specialists within a Public Safety Communications Center
Full text linkPublic support for reducing the role of the police in situations involving persons with mental illness (PWMI) has gained significant momentum in recent years. As a result, many jurisdictions have introduced initiatives that prioritize connecting PWMI with the type of resources best equipped to support them. A related but relatively nascent idea involves co-locating behavioral health specialists within public safety communications centers (e.g., where “911” calls are received) so that these professionals can be on hand for calls for service concerning PWMI. By incorporating behavioral health specialists within communications centers, PWMI can be diverted away from the criminal justice system at the first stage of the contact process. This study uses a multi-method approach applying original field research conducted inside one of the largest public safety communications hubs in the United States to determine the feasibility and practicality of embedding behavioral health specialists within a public safety communications center. Using data gathered through (1) systematic observations of mental health-related calls for service, (2) an employee survey, and (3) a focus group discussion with employees, this study gauges the extent to which these initiatives are suited to addressing different types of mental health-related calls for service. It also considers possible benefits and challenges to implementation within the context of a public safety communications center. Findings suggest that certain types of mental health calls for service are far more ambiguous and challenging than others, presenting obstacles for diverting calls away from law enforcement. Findings also uncovered a divergence between what callers want and what reformers want, with callers still relying heavily on the police to resolve problems despite calls from reformers to shift this responsibility to an alternative resource. Moreover, the findings highlighted the challenges associated with addressing the underlying causes that motivate specific mental health calls for service and how these calls can result in persistent, non-crisis calls. Finally, this study provides insight into the complex process behind the implementation of co-located behavioral health specialists within a public safety communications center regarding organizational constraints, concerns over safety and liability, and efforts to establish clear expectations and maintain distinctions between the various roles and responsibilities that must be coordinated to respond to mental health-related calls for service
Data-driven Spiking Neural Network Models that Refine Theories of Hippocampal Function
No full textComputational modeling complements and expands the benefits of animal experimentation. Hippocampome.org is a key resource for modeling neural activity exhibited by the hippocampal formation. My work addresses a gap in knowledge, namely how to find and use experimental work to increase the realism of hippocampal spiking neural network simulations. The overarching aim of my doctoral research was to create more Hippocampome.org resources and to use those resources to produce a spatial navigation simulation that closely matches real cell activities. I created a literature review and knowledge base of spiking neural networks in the hippocampal formation named Cognome. Findings included in Cognome, as well as several additional Hippocampome.org properties, informed the use of methods in the creation of a spatial navigation simulation. The simulation’s parameters included the use of results from research projects I worked on such as identifying synaptic probabilities and modeling, the creation of CARLsim 6, and measurements of grid cell firing metrics. I also contributed to research on neuron-type specific oscillatory phase locking in vivo and generated preliminary results of my spatial navigation simulation for Hippocampome.org’s version 2.0 release. Results of my work include several additions to Hippocampome.org resources, such as front- and back-end development of multiple functionalities, including browsable tables, display of experimental evidence, and online computational tools. My work on Cognome facilitates researchers’ abilities to find categorized knowledge on their cognitive functions of interest, as well as accompanying statistics. My work on a spatial navigation simulation adds to knowledge about the subject, for example, creating testable predictions about neural properties that generate characteristic grid cell firing. The open source release of this work makes it a beneficial tool for more computational researchers. The simulation reproduces well an assortment of neural firing activities of real cells. The work thus serves as an example for the research community of how Hippocampome.org resources can be integrated into popular network-level algorithms and theories, and how the resultant biological realism can facilitate comparisons with animal experimentation results
Exploring Police Exposure to Critical Incidents, Perceived Stress, and Turnover Intention in a Suburban-Rural Jurisdiction
Full text linkLaw enforcement is a physically and mentally demanding occupation. Police officers are not only repetitively exposed to traumatic events in the line of duty but also at higher risk of developing mental health problems. The accumulation of work-induced stressors such as primary traumatic incidents or exposure to citizens’ trauma/victimization over time may have deleterious impacts on officers’ wellbeing. While there has been some research focusing on officers’ mental health, the vast majority of the prior research was conducted in urban settings or large police departments, leaving a gap in understanding the unique challenges encountered by rural and suburban police officers and their mental health. This dissertation contributes to the existing knowledge by demonstrating the prevalence of critical incident exposure in a suburban-rural jurisdiction and examining how cumulative exposure to critical incidents affects officers’ perceived stress at work and whether perceived stress, in turn, affects turnover intention. The cross-sectional survey data were collected from a suburban-rural police department in Southwest Virginia during the implementation of a departmentwide wellness checks program conducted by a local mental health service provider in 2022. In order to address the research questions, descriptive statistics were reported to demonstrate the prevalence rates of critical incident exposure, and structural equation modeling (SEM) was used to examine the research hypotheses: (1) Officers with more critical incident exposure in the past experience a higher level of perceived stress at work; (2) resilience is a protective factor of stress; resilience can moderate the impact of cumulative exposure to critical incidents on stress; and (3) a higher level of perceived stress at work is positively associated with officers’ intention to leave law enforcement. Overall, I found that critical incidents involving personal threats or exposure to citizens’ trauma/victimization are more common than use of force incidents and death/injury of a colleague in the study site. Notably, of all the incidents, the prevalence rates are high in certain types of incidents in this study site compared to urban jurisdictions including being threatened with a gun or a knife/other weapon and loved ones being threatened. The prevalence rates of all secondary traumatic exposure are comparable with the rates found in urban jurisdictions such as exposure to physically or sexually assaulted child/adult or death-related incidents like making a death notification. As expected, the overall cumulative exposure to critical incidents is not as high in this suburban-rural setting as in urban settings. Nonetheless, the SEM results show that the cumulative exposure still presents a risk to officers’ perceived stress at work, which, in turn, is associated with a higher level of turnover intention. The analyses also reveal that resilience is a potential protective factor that can shield officers from feeling stressed due to exposure to repetitive critical incidents. This research provides important policy implications for law enforcement organizations. Collecting and tracking critical incident exposure data is crucial to identify officers who might be at high risk of mental health issues throughout their career. Implementing wellness checks conducted by an independent organization might be a feasible approach in law enforcement to track officers’ mental wellbeing. Moreover, enhancing officers’ self-resilience should be an integral part of prevention and intervention programs to improve officer wellness in law enforcement
"Peace is Our Thing": A Participatory Action Research Project with Youth Peacemakers in Baltimore
No full text“PEACE IS OUR THING”: A PARTICIPATORY ACTION RESEARCH PROJECT WITH YOUTH PEACEMAKERS IN BALTIMORENawal Rajeh, Ph.D. George Mason University, 2024 Dissertation Director: Dr. Susan H. Allen “Peace is Our Thing”: A Participatory Action Research Project of Youth Peacemakers in Baltimore, MD,” explores how a group of 10 youth at a Baltimore community peace program (Peace Camp) process the world around them and the role that peace education can play in creating meaningful and sustained change in their lives. Our PAR research team, composed of the author of this dissertation and 10 youth participants, set out to answer research questions around the evaluation of the Peace Camp experience as an intervention program, as well as explored issues surrounding policing, youth voice and agency, and civic education that excludes their realities and experiences. Conducted as a qualitative study, the research consisted of interviews, facilitated meetings, a focus group, and an “action” taken collectively and chosen by the youth members of the research team. In addition to uncovering new collective knowledge around the ways youth navigate challenges while holding their identity as peacemakers, the findings of this research suggest that PAR can enhance and complement peace interventions, that culture plays a role in building safe spaces for youth, and that youth voices are both stifled and empowered through formal and informal institutions. The study supports the development of policies from city governments to expand, fund, and support youth centers, peace centers, and peace programs like Peace Camp as interventions to create more lasting individual transformation and community change. It is also a case study for the field of Peace and Conflict Studies in how long-term, community-based interventions can sustain identity change and create a community of people who make peace “their thing.
Occlusion, Transparency, and Depth Effects in Visual Search for Laboratory and Familiar Real-World Objects
No full textThis work is embargoed by the author and will not be publicly available until May 2026.When visual search occurs in unnatural scenes (e.g. TSA baggage screening), we do not have contextual cues from top-down processing to aid search (e.g. initial searches for a laptop in an office may occur on top of a desk or in a bookbag), and in crowded scenes, the chance of occlusions occurring between targets and distractors increases, and occlusion affects our perception of objects. When laboratory objects are not fully visible, search is inefficient if there is a gap of visible information within an object, and search is even more inefficient when there is a distractor object on top of a target. To explore whether these visual search results are similar between laboratory and real-world objects, Study 1 (Experiment 1) examined if the type of missing visual information affected feature search of familiar real-world objects (Hershey Bar and a Remote Controller). In addition, Study 1 (Experiment 2) also tested whether there were differences between feature and identity searches (the latter is more typical in real-world scenarios). Bayesian analyses between occluder and stimuli type resulted in stronger evidence that search for complex objects is more effortful, and missing visual information was disruptive. White occluders affected feature searches more than identity searches. To determine if target depth and distractor object opacity levels drive search (when occlusion is present), Study 2 (Experiment 1) addressed if search for targets “above” a distractor was easier than search for targets “below,” and this study also addresses how search is affected by different distractor opacity levels (0%, 25%, 50%, 75%, 100%). To test whether an irrelevant feature (color) affects orientation search, Study 2 (Experiment 2) participants searched for a vertical bar (amongst horizontal bars) that was light blue or light yellow (colors sensitive to detection). Bayesian analyses show that the best model predictor for search of transparent stimuli includes depth and diagonal opacity--not including color. To test whether search for real-world targets was affected by depth and occluder opacity compared to a simple object, participants searched for Hershey bars or Remote Controllers (Study 3, Experiment 1) and grayscale-Hershey bars or grayscale Remote Controllers (Study 3, Experiment 2) with the same design and conditions as Study 2. Bayesian analyses show strong-to-decisive evidence for easier searches when objects are “above” a distractor, for differences between simple and complex real-world objects occuring in search for targets below a distractor object, and for differences between complex, real-world objects occur when targets are below and distractors are at 50% (and higher percentages) of opacity. Finally, Study 4 addresses how occlusion (0%, 25%, 50%, 100%) affects search for real-world objects when familiar real-world object distractors can partially occlude the target. In addition, stimuli type was manipulated between subjects (Normally colored, Grayscale, Transparent-Colored, Transparent-Grayscale). Since Study 1 and 3 results show evidence that occlusion decreases search efficiency, this study also addresses whether increasing levels of occlusion affect search efficiency. For naturally chromatic (colored) objects, transparency made search harder compared to opaque colored objects. For achromatic (grayscale) objects, there were no search efficiency differences between opaque and transparent objects. Thirdly, as a follow-up to study 3 on depth effects for object identity search, analysis on relative target-to-distractor layer effects was also conducted, and there was a significant layer effect, but follow-up Helmert contrasts show that significant differences only occurred between the target layer that has no occlusion and target layers with occlusion. Overall, when searches occur in congested scenes where occlusion is prevalent, depth and occlusion type affect feature and identity search for laboratory and complex, real-world objects. In addition, chromaticity seems to aid search for opaque, real-world objects.2026-05-1
INFLAMMATORY SIGNALING PATHWAYS IN ULCERATIVE COLITIS
Full text linkInflammatory bowel disease (IBD), including both Crohn's disease (CD) and ulcerative colitis (UC), is a complex condition that is characterized by immune system abnormalities as its fundamental cause. Despite the exact origin of these disorders remaining unknown, it is clear that many factors containing immunological, genetic, environmental, and microbial elements play a role in the pathogenesis of IBD by affecting the regulation of mucosal immunity and the integrity of the intestinal mucosal barrier. Traditional diagnostic and treatment approaches for IBD require invasive tests and procedures that can be both discomforting and risky to patients. To overcome these diagnostic challenges, the search for non-invasive biomarkers aims to replace these uncomfortable procedures. In this research, we have three core objectives, seeking to illustrate molecular basis underlying of IBD that can ultimately lead to enhance diagnostic capabilities and personalized strategies for treatment. Aim 1 Focuses on identifying UC biomarkers and genetic factors. Bioinformatics analysis identifies differentially expressed genes (DEGs) linked to UC and confirms their significance. This exploration paves the way for potential diagnostic markers and sheds light on UC's genetic foundations. Aim 2 distinguishes CD from UC by scrutinizing unique characteristics and mechanisms. Using a GEO dataset, genes significantly altered in UC patients, yet not in CD, are revealed, offering potential diagnostic insights. Tissue-specific gene expression patterns are also examined to pinpoint distinguishing markers. Pathway analysis unveils underlying molecular pathways, enhancing our understanding of CD and UC differences. Aim 3 delves into the role of T-cell inflammatory responses in IBD. The analysis identifies genes associated with T-cell function and their significance in UC. It unearths immune dysregulation, reaffirms the role of inflammatory responses in IBD, and highlights relevant pathways. In summary, this research navigates the complex landscape of IBD, from identifying biomarkers and genetic factors in UC to distinguishing CD from UC and exploring the essential role of T-cell responses in IBD. These findings offer potential diagnostic and treatment opportunities in IBD management
An Inquiry of Health Narratives of South Asian Immigrant and International Communities in the U.S.
No full textThe dissertation aims to explore the healthcare experiences of South Asian immigrant and international student communities in the U.S. healthcare system. Despite a significant number of immigrant population in the U.S., its’ healthcare system fails to fully engage with these communities in a way that is meaningful/beneficial to them. This study addresses the lack of research on South Asian immigrant/international student health narratives, focusing on their experiences accessing and navigating healthcare in the U.S. Through narrative-based interviews, it listens to their experiences as patients, caregivers and information-seekers, shedding light on how access issues exist for them and how they make choices in regard to access in the U.S. healthcare setting. By situating this work at the intersection of technical communication and rhetoric of health and medicine, it aims to initiate scholarly conversations and pedagogical practices on healthcare access for South Asian as well as broader marginalized immigrant and/or international student communities existing in the U.S. healthcare system
SOUTH SUDANESE YOUTH, THE ROLE OF CIVICS EDUCATION, AND THE WAYS OF IMPACT ON CIVICS EDUCATION
Full text linkThis study explored 12 South Sudanese males and females, aged 18-30, residing in Kampala, Uganda, regarding the role of civics education and understanding how they experience civics education, civic agency, and civic engagement. Rather than have participants respond to preconceived notions of what civics education is, this qualitative study, through a hermeneutic phenomenological methodological approach, investigated how youth describe their experiences of civics education to uncover deeper understandings and meaning making. By understanding the relationships between conflict and education and how students conceptualize civic engagement and civics education in social cohesion, this study aimed to better understand how South Sudanese youth conceptualize the role of civics education, and the way youth look at civic engagement towards their own agency. This study also aimed to better understand how South Sudan youth play a role in developing civics education curriculums in South Sudan and its diaspora. In person individual interviews were conducted twice with each participant and resulted in four common themes: (a) impact of conflict and displacement on defining civics education, (b) Practical and experiential applications of civics education, (c) awareness of rights and responsibilities, and (d) teaching history from a diverse, non-Western perspective. The study findings highlighted that South Sudanese youth hold a significant role in shaping civics education and are capable and experienced stakeholders to amplify the importance of civics education and its impact on South Sudan education, and underscore their perseverance and responsibility to their communities and country