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Psychopathy and Moral Decision Making
No full textSince the 1800s, psychopathy has been regarded as the absence of morality. The goal of our study was to explore whether psychopathic traits can affect the moral decision-making process in sacrificial moral dilemmas. Participants completed multiple self-report measures of psychopathic traits, utilitarian tendencies, and 16 sacrificial moral dilemma vignettes. After each hypothetical vignette, participants decided whether they believed it was morally right, permissible, and whether they behaviorally intended to sacrifice one person to save five people. Positive correlations emerged among all variables, which allowed us to perform a mediation analysis. Instrumental Harm – the idea of sacrificing one individual to save a greater number – accounted for more than half of the relationship between Callous Affect traits and ratings of Permissibility and Behavioral Intent. Specifically, the bias corrected indirect effect for permissibility was 0.07 (95% CI [0.01, 0.14]), which represents 54.5% of the total effect. The bias corrected indirect effect for behavioral intent was 0.08 (95% CI [0.01, 0.15]), which represents 53.6% of the total effect. Results indicated that participants high on psychopathic traits find it permissible and had the intent to sacrifice one person to save five. These findings imply that the concept of “moral insanity,” long associated with psychopathy, may not be an accurate representation of this population. Instead, it seems that individuals with Callous Affect psychopathic traits find it more permissible and are more likely to act on behaviors that minimize suffering for the largest amount of people
From Resistance to Host Response: An Integrative Study of C. difficile Infections
No full textClostridioides difficile infection (CDI) is a major healthcare challenge, causing severe gastrointestinal illness and significant mortality. Understanding the mechanisms of antibiotic resistance, epidemiology, and immune response in CDI is critical for developing effective treatments and prevention strategies.
This dissertation encompasses three complementary studies. The first study investigates the genetic mechanisms underlying cephalosporin resistance in C. difficile strain 630 through differential gene expression analysis. The second study provides a descriptive epidemiological analysis of C. difficile ribotypes in a Las Vegas patient population, highlighting differences between healthcare-associated (HA-CDI) and community-associated (CA-CDI) cases. The third study integrates serum analyte profiling and transcriptomic analysis to explore the differential immune responses in CDI, with a focus on the role of sex hormones.
The gene expression analysis identified several putative antibiotic resistance genes, including blaCDD, significantly upregulated in response to cephalosporin exposure, though deletion of these genes did not significantly affect cephalosporin resistance. These findings suggest an intrinsic resistance mechanism in C. difficile. The epidemiological study revealed diverse ribotypes with distinct distributions between HA-CDI and CA-CDI cases, with ribotype 027 being notably prevalent in healthcare settings. The integrative analysis of serum analytes and transcriptomics showed distinct hormone and cytokine profiles correlating with CDI severity and recovery, suggesting that hormonal fluctuations significantly influence immune responses.
This multi-faceted approach provides comprehensive insights into the genetic, epidemiological, and immunological aspects of CDI. The findings emphasize the need for alternative therapeutic strategies to combat antibiotic resistance, and continuous surveillance to manage CDI outbreaks. These integrated insights can guide the development of more effective interventions for preventing and treating CDI
Physiology and Genomics at the Bottom of the World: Genome to Phenome
No full textMammals are exposed to a suite of physiological challenges based on the environment in which they inhabit. Animal individuals can overcome challenges associated with the dynamic nature of their habitat through variation in phenotypic traits. The plasticity of a phenotype relies on an individual’s genome and the transcription factors that act on regulatory elements. Species living in Antarctica display physiological specializations to withstand harsh conditions, such as severe cold temperatures, shifts in available ice habitat, and annual fluctuations in daylight. To explore the connections between an individual’s genome and its phenotype, we investigated two physiologies of the Antarctic Weddell seal (Leptonychotes weddellii), diving and reproduction. We integrated multiple cellular and bioinformatic tools to investigate Weddell seal physiology based on the newly published genome.
Among phocids (true seals), Weddell seals are some of the deepest, longest divers with the ability to dive over 900 meters deep and spend over 90 minutes underwater. This behavior is supported by extensive breath-hold capacities that are facilitated by mechanisms such as 1) near-complete depletion of venous blood oxygen supplies and 2) compression of the lung under high pressures to limit barotrauma risks. These physiological features indicate that diving seals are routinely exposed to hypoxemia and atelectasis. These are considered pathologies in humans, both with sequelae mediated through stimulation of the innate immune system, directed by inflammatory cytokines. One hypothesis for how seals sustain repeated diving without development of chronic injuries is the seal’s ability to dampen their inflammation response. We investigated two components in Weddell seal blood that protect against inflammation. Chapter 2 characterized serum protein components and investigated whether protection is inherent in Weddell seals from birth or developed subsequent to diving behavior. We used an in vitro mouse macrophage model to test whether seal serum is protective against inflammatory stimulant lipopolysaccharide (LPS) and measured pro-inflammatory cytokine production following 6-h exposures. We correlated these measurements to diving behavior in 2 ways: 1) comparing inflammatory responses between experienced diving adults to novice diving pups (~35 days post-partum) and 2) correlating dive response across species with varying dive behaviors. Adult seal serum blunted the inflammatory response in mouse macrophages to a greater degree than their pup counterparts, and serum from Weddell seals is the most protective across all species examined. Additionally, proteomic analysis between pup and adult serum revealed differences including the abundance of colony stimulating factor 2 receptor beta (CSF2RB), which was 23-fold higher in adults than in pups.
Serum is only one component in blood, so we additional tested the inflammatory response in Weddell seal white blood cells. White blood cells have nuclear machinery and can mount a transcriptional response to a stimulus. When a tissue is inflamed, macrophages are among the first white blood cell that is recruited and will function to both rid the area of damage and initiate repair signaling. For chapter 3, we investigated the transcriptional difference between Weddell seal and human macrophage responses to LPS-induced inflammation. Weddell seal diving evokes hypoxemia (drop in blood oxygen levels), which in turn induces inflammation. This chapter had two main findings: 1) Weddell seal macrophages respond less to inflammatory stimuli compared to human cells, as evidenced by both a reduction in total number of differentially expressed genes (DEGs) and by a smaller fold change; and 2) Weddell seals activate unique DEGs reflecting enrichment of biological pathways that are distinct from human cells. We additionally analyzed the response of Weddell seal, human and Northern elephant seals (Mirounga angustirostris) macrophages to a dual LPS and hypoxia (1% oxygen) exposure. We found that Weddell seal macrophages have less mRNA expression for pro-inflammatory cytokines (Il6 and Tnf-) following dual exposure compared to the other species. Furthermore, Weddell seal macrophages have the highest mRNA expression of anti-inflammatory cytokines (Il1r and Tgf-) following dual exposure compared to the other species.
As the southernmost breeding mammal in the world, the reproductive physiology of Weddell seals is also worthy of investigation. The Erebus Bay population of Weddell seals is one of the most extensively studied free-ranging populations of large mammals and is part of an ongoing 50-year mark recapture study tracking demographic shifts in the population. Prior work identified a range of reproductive rates in the population of adult females, considered to have either a reproductively high output (average fecundity is higher than the population average) or reproductively low output. Chapter 4, outlines a pipeline to analyze genomic variants across 45 individuals representing high-, average-, and low-output females. We ran targeted analysis of 29 genes grouped in biological pathways associated with pregnancy, blastocyst invasion/implantation, inflammation, and cortisol. We ran a linear regression to determine if genetic variation among our sample’s genotype is correlated with reproductive output (standard deviation determined based on an individual’s total pup output from the average output). Across the 29 genes tested, we identified 222 variants (p-value \u3c 0.05) that could be explained by the reproductive output. Among the genes, ESR1, which encodes for estrogen receptor 1, was the gene with the most variance among loci primarily associated with low-output females. While we were able to identify statistical significance, multiple considerations were discussed related to future directions.
This dissertation links genetic traits to multiple aspects of phenotype and physiology in Weddell seals. In comparative physiology, understanding how mammals can thrive in extreme environments can be a proxy to understand the boundaries of human health. Uncovering unique genes and regulatory processes that underlie physiological phenotypes can be a tool for developing targeted therapies in human medicine
Density-Driven Investigations of Ruthenium Binary Compounds RuX2 (X = O, S, N)
No full textExploration and fine-tuning of the energy landscape of materials can be accessed by means of changes in material density, a key principle of high pressure research. Density-driven changes impact variations in oxidation states and coordination numbers for the element constituents of a compound. Pressure-induced modification of intrinsic density can promote the formation of new materials, variations in physical properties, and transformations in crystallographic symmetry. With this as our foundation, we focus on ruthenium binary compounds - altering the anion species to change electronegativity while probing pressure and temperature effects. This led us to the present study of ruthenium oxide RuO2, nitride RuN2, and sulfide RuS2, wherein we measure the pressure response of physical properties and characterize corresponding crystal structures. We report the discovery of multiple new high pressure phases of RuO2, the first high pressure experiments on RuS2, and the formation of RuN2 while seeking to explore new materials through high-pressure, high-temperature synthesis. These works utilized a combination of high pressure synchrotron x-ray diffraction, in-house Raman spectroscopy, diamond anvil cell electrical transport, laser heating, and cryostat techniques, with additional support and insight from DFT simulations
Implicit Bias: Principal Leadership and Social Justice
No full textBenson & Ellison (2017) contend that among the first steps toward addressing a more diverse school and student body is an augmentation of cultural competency leadership, which begins with principals knowing how to address their own implicit biases as leaders in their schools. The purpose of this qualitative research study was to explore different ways principals address implicit biases within their schools and what is needed to help them address implicit bias with teachers and staff. The study addressed two research questions: “What do school principals perceive as biases among teachers and staff?” and “What do principals perceive is needed to help them address implicit biases in their schools?
Resource Allocation for Vehicular Communication Systems
No full textSmart cities utilize real-time data to enhance mobility, connectivity, and safety services. Intelligent transportation systems (ITS) play a crucial role in this endeavor, striving to innovate, plan, operate, evaluate, and manage transportation systems through advanced information and communication technologies. Among these technologies, vehicle-to-everything (V2X) communication systems serve as key enablers for ITS. A leading wireless communication technology to realize V2X communications is the cellular-V2X (C-V2X) network leveraging wireless cellular networks for vehicular communications. However, the performance of C-V2X systems is significantly influenced by resource allocation challenges, including radio resources such as spectrum, transmission power, and energy consumption. This dissertation aims to design resource allocation schemes for vehicular communications in C-V2X networks. Given the limited resources and unique characteristics of vehicular communication systems, such as high vehicle mobility and diverse quality of service (QoS) requirements, the study explores techniques like full-duplex (FD) communications, frequency reuse (FR), and integration of unmanned aerial vehicles (UAVs) to enhance system efficiency. The dissertation addresses five challenges in vehicular communication within C-V2X networks. In the first problem, we address the issue of resource allocation in C-V2X networks, where both cellular and vehicular users contend for limited resources while possessing distinct QoS requirements. Subsequently, the focus narrows to vehicular users exclusively to enhance system efficiency considering resource constraints. The second problem centers on enhancing spectral efficiency in C-V2X networks through FD and FR techniques. In the third problem, the deployment of UAVs to provide communication services to vehicular users in intersection scenarios is explored, offering an energy-efficient resource allocation scheme. Moving forward, the fourth problem investigates the deployment of multiple UAVs in highway scenarios, comparing hovering and flying deployment strategies in terms of resource allocation efficiency. Finally, the fifth problem combines FD and UAV technologies, deploying an FD UAV to provide communication services to a group of vehicular users on a highway, presenting a comprehensive resource allocation policy. For each problem, the dissertation presents the system model and mathematically formulates the resource allocation problem as an optimization problem. Mathematical optimization techniques are employed to address problems one to four, while problem five utilizes reinforcement learning. Simulation results are utilized to evaluate the performance of the proposed schemes
The Role of Cognitive Dysfunction in Late-Life Depression
No full textDepression is one of the most common psychiatric concerns in older adults. Because of the intersection of biological, emotional, social, and cognitive factors that are at play in depression, symptoms are often heterogeneous in presence and severity. In combination with the expected changes in cognitive abilities as one ages, late-life depression can be additive to these changes. The higher risks of neurodegenerative processes and vascular events in later life can cause, magnify, or accelerate cognitive decline. As such, individuals with late-life depression often present with a complex array of problems that can impact cognition and functioning, and thus complicate the implementation of traditional psychotherapies. Although treatment methods have been adapted to target late-life depression, they are often modifications of treatment approaches for depression in other age groups, rather than developments to directly address unique late-life depression presentations. This dissertation will investigate and discuss aspects of our understanding of the role of cognitive functioning in late-life depression, with the overarching goal of narrowing the focus of research and clinical practice to targeting shortcomings and improve late-life depression treatment. The three main aims of the dissertation are broadly, (1) identify how the scientific literature accounts for cognitive functioning in late-life depression psychotherapy research, (2) determine whether cognitive functioning predicts late-life depression psychotherapy treatment response, and (3) understand the barriers and facilitators to practical implementation of an adapted psychotherapy for late-life depression
LMS Acceptance by Higher Education Faculty Post-ERT Due to the COVID-19 Pandemic
No full textThis study investigates the impact of emergency remote teaching (ERT) during the COVID-19 pandemic on faculty acceptance of learning management systems (LMS) in higher education. Using an extended Technology Acceptance Model (TAM) that incorporates resistance to change factors, this research examines the relationships between perceived ease of use, perceived usefulness, and behavioral intention to use an LMS. Additionally, it explores how four elements of dispositional resistance to change—routine seeking, emotional reactions, short-term focus, and cognitive rigidity—influence faculty\u27s intention to use an LMS.
The study investigated the relationships between learning management system (LMS) acceptance, resistance to change, and post-emergency remote teaching (ERT) LMS intended use among higher education faculty. Using the Technology Acceptance Model (TAM) and Resistance to Change Scale, a quantitative survey was conducted with 123 faculty members from seven public higher education institutions. Multiple regression analyses revealed that perceived ease of use and perceived usefulness were predictors of behavioral intention to use LMS, with perceived usefulness having the strongest positive relationship (β = .711, p \u3c .001). Among resistance to change factors, only routine seeking showed a significant, negative relationship with behavioral intention (β = -.201, p = .026). The study contributes to understanding faculty LMS acceptance in the post-ERT context and provides insights for higher education institutions in supporting faculty\u27s continued use of an LMS
Peer Led Learning Curriculum on Sexual Education
No full textSexual education is a necessary course that teaches students about health and safety. There have been many obstacles that educators have faced in implementing into schools. This has led to a statewide division in how the topic is taught. Because of this, gaps in students\u27 knowledge can lead to harmful practices or actions. A comprehensive sex ed, or CSE, needs to be utilized across the United States as this curriculum focuses on empirically based evidence and facts. Having an unbiased curriculum will improve student’s knowledge and help prevent parent backlash. However, sex ed needs to embrace peer-led learning as many students have prior knowledge about sex ed, whether due to other peers or the internet. This thesis combines both principles and offers a new curriculum to be taught in the Clark County School District among high schoolers. This new curriculum will open the doors for further research and can be built upon for future studies
Climate and Gypsum Parent Material Shape Biocrust Communities and Moss Ecology in the Chihuahuan and Mojave Deserts
No full textBiological soil crust communities (biocrusts) establishing on gypsum soils have been well-documented for their prolific appearance and rich diversity of lichens and bryophytes. However, studies characterizing gypsum biocrusts have occurred primarily outside of the U.S., most of which lack comparisons to other soil types. We conducted intensive field surveys to evaluate the ground cover and frequency of biocrust functional groups and moss species on gypsum and non-gypsum soils in the U.S. regions with the most extensive gypsum outcrops, the northern Chihuahuan and eastern Mojave Deserts. Study sites were stratified by geomorphology and paired, so that every gypsum site was matched with a non-gypsum site in the same region. We employed canonical correspondence analysis (CCA) to relate the observed differences in biocrust abundance and composition across soil types to distinct environmental variables. Additionally, we assessed species richness of biocrust mosses on gypsum versus non-gypsum soils, as well as in the Chihuahuan versus Mojave Deserts. Our results indicate that differences in biocrust communities on gypsum and non-gypsum soils are predominantly due to gypsum’s profuse dark algal (mostly cyanobacteria-formed) rather than lichen and moss biocrusts in these two hot desert biomes. Biocrust functional groups did not exhibit distinct associations with environmental variables. However, moss species appear to be strongly influenced by environmental variables and exhibited differential preferences for substrate parent material. Moss species richness was greater on gypsum soils and, surprisingly, in the hottest and driest North American Desert, the Mojave. Differences in species richness across deserts were strongly correlated to mean annual and seasonal temperatures, as well as mean winter precipitation. Overall, our data suggest that environmental and climate conditions all play important roles in the ecology of biocrusts, specifically moss diversity and distribution, in the northern Chihuahuan and eastern Mojave Deserts of the U.S. More importantly, we emphasize that gypsum soils of the U.S. are unique refugia for moss-forming biocrusts