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I−V Characteristics of Chiral Orbital Materials Mn3(Si1−x)Ge(x))2Te6 and Mn3Si2(Te(1−x)Se(x))6
Get PDFColossal Magnetoresistance (CMR) is characterized by a dramatic drop in resis-tivity under a small magnetic field. A similar effect, Giant Magnetoresistance, hasbeen utilized in magnetic memory storage to significant effect. CMR, being a muchmore sensitive effect, has great potential to be applied in similar systems. How-ever, the current understanding of the phenomenon is limited. The ferrimagneticinsulator Mn3Si2Te6 demonstrates a dramatic 7 order-of-magnitude negative MReffect, without the traditional spin polarization found in most magnetic materials.This effect has been explained by chiral orbital currents (COC) that encircle theMnTe6 octahedra. These COC become aligned under the magnetic field in place ofthe atomic spins. The COC may explain a number of other unusual effects presentin the electric transport properties of the material, including a first-order switchingtransition between two regions Negative Differential Resistance (NDR) present inthe I − V characteristic at 10K.
Introducing impurities of Ge and Se can have dramatic impacts on the I − Vrelationship. Replacing 5% of the Si with Ge can strengthen the NDR, expandingthe range of current and temperature where this effect occurs. Doping 7% of theTe ions with Si dramatically strengthens the NDR effect, persisting at 14T, whilestill preserving some of the switching effects.</p
Cadaveric Ethics in Figurative Art Instruction: Developing A Workshop for an Anatomical Approach
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In the modern era, learning from cadavers is an opportunity typically reserved for anatomy students, however, artists seeking to accurately represent the human form can benefit from the same experience. Through the development and facilitation of an “Anatomy for Artists” workshop in the CU cadaver labs and accompanying anatomical illustrations, the present work seeks to educate artists on anatomical information anatomical relative to their figurative work. Additionally, because cadavers are the primary source of information for the workshop, the historical context and contemporary ethics of dissection are intertwined with anatomical art in an interdisciplinary dialogue of science and art.
Through upending marginalization—in both art and anatomy—and exploring cadaveric ethics, this thesis weaves art, anatomy, history, and ethics to establish a new pedagogical approach at CU Boulder. The resulting workshop informs students of anatomical structures, equips them with the knowledge to advocate for ethical dissection practices, and ultimately creates a map for a more equitable and diverse future in cadaveric dissection and figurative art.
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Judgments of Response Speed as a Potential Screening Tool for Children from Diverse Language Backgrounds
Get PDFThis study investigates whether adults can identify children at risk for language impairment (LI) across different language backgrounds. Participants included 28 monolingual adults (Mean age = 22.03 years, Range = 20-28 years) who were asked to complete a judgment task. In this task, they listened to 60 paired audio clips, each pairing consisting one typically developing (TD) child and one child with a LI. The children, with a mean age of 59.83 months (SD = 6.76), came from three language backgrounds—Cantonese-English bilingual, Spanish-English bilingual, and Vietnamese monolingual children. Participants were asked to determine which child responded more slowly. The results showed that shorter clips led to higher judgment accuracy than longer clips. Adults demonstrated the highest accuracy when judging Cantonese-English bilingual children, while the lowest accuracy occurred when judging Vietnamese monolingual children. Additionally, there was no significant difference in accuracy based on whether the language was the child’s first or second language. These findings suggest that response speed may be a potential screening tool for language impairment, but variability across language groups and audio clip lengths indicates the need for further research. </p
Classical Lyapunov Exponents for the Hydrogen Atom
Get PDFFor classical chaos to occur, the equation of motion for the system has to be non-linear; incontrast, the Schrodinger equation in quantum mechanics is a linear differential equation, beggingthe question of how chaos arises from non-chaotic origins. One tool being heavily scrutinizedright now is the Lyapunov exponent. If a system’s sensitivity to initial conditions is exponential,with the exponential being characterized by the Lyapunov exponent, then the system is consideredchaotic. However, there are systems that are famously non-chaotic but have a Lyapunov exponent,making the effectiveness of it as a chaos diagnostic tool ambiguous. To help dispel this confusion,the Lyapunov exponent is calculated for the classical hydrogen atom, a known integrable system,finding that indeed there is one, but also that the value itself depends highly on the total angularmomentum of the system.</p
CHANGES IN PLANT SPECIES DIVERSITY AND FUNCTIONAL TRAITS DUE TO DROUGHT IN COLORADO
Get PDFDrought, exacerbated by climate change, presents an increasing threat to ecosystems, particularlyin the Southwestern United States, including Colorado. Extreme drought events compromiseboth biodiversity and ecosystem functioning, requiring plant communities to adapt to prolongedwater stress. This study investigates the role of plant functional traits and their diversity inenhancing grassland resilience by evaluating changes in productivity, biomass, and speciesdominance across three rainfall treatments: control, drought, and water addition, at anexperimental site in Boulder, CO. Results showed that while drought reduced biomass andbiomass resistance, it increased temporal biomass stability. Contrary to expectations, functionaldiversity did not significantly enhance resistance or stability, and fewer interactions betweenfunctional traits and treatments were observed than anticipated. Instead, resilience appeared to bedriven by species-specific traits, as communities shifted toward drought-tolerant species. Thesefindings suggest that trait-based diversity alone does not determine grassland stability underdrought, highlighting the context-dependent nature of community responses and the role ofspecies plasticity in ecosystem resilience.</p
A Qualitative Study on the Relationship Between Climate Activism Spaces and Live Music
Get PDFThis study focuses on finding the impact of using live music in climate activism spaces. By thinking of music as a way to communicate creatively, targeted audiences are observed at a multitude of events attended by Boulder, Colorado community members. The data is collected qualitatively from the perspective of the event planner who is also the soul researcher. This data includes audience observation, self-reflective journaling, literature review, and event specific qualitative data recording. Research is conducted at a variety of venues and takes place over an eight month period. The results of this study are recorded by the researcher and presented within this thesis in connection to relevant literature supporting the data. Significant events include, Stand Up for Climate Comedy 2024, Electric Honey Experience 2024, Climitique Imagination Portal December 2024, and a number of other small-scale musical gatherings near the CU Boulder campus. </p
The Impact of Cannabis Use Frequency on Neuronal Markers of Response Inhibition and Cognitive Control in a Go/No-Go Task
Get PDFCognitive control is an essential self-regulatory mechanism that selectively modulates attention processing by suppressing inappropriate responses (a process known as response inhibition) and is regulated by the prefrontal cortex (PFC). The PFC is responsible for evaluating novel stimuli and executing adaptive responses. Exogenous substances like cannabis have been found to disrupt the functioning of the prefrontal cortex. Thus, electroencephalogram (EEG) recordings were used to assess electrical activity at the cortical level during a cognitive performance task—the go/no-go paradigm—to capture stimulus-locked event-related potentials (ERP) of “never,” “infrequent,” and “frequent” cannabis users. Data analysis focused on the N200 amplitude, an indirect measure of cognitive effort. Thus, we hypothesize that frequent cannabis use is associated with increases in negative-going N200 amplitudes during a go/no-go task, suggesting a greater need for cognitive control to achieve successful inhibition. However, given that previous studies have identified potential gender interactions in cognitive control and substance use, we further hypothesize that gender will moderate these effects. We also do not expect significant impairments in behavioral performance (i.e., accuracy on go/no-go trials). A regression model analyzing both categorical and continuous cannabis use demonstrated significant effects of cannabis use, gender, and response type. For categorical cannabis use, men showed a greater mean N200 amplitude compared to women, and Hits elicited a greater mean amplitude than correct rejections. For continuous cannabis use, the effect of response type was significant, such that Hits elicited a greater mean amplitude than correct rejection. This investigation shows that cannabis use and gender modulate neuronal markers of response inhibition and cognitive control and showcases the significance of further investigations on the long-term effects of cannabis use on higher-order cognitive functioning.</p
The Campaign Against Birth Control: Medical Misinformation, Disinformation, and the Rise of Wellness Narratives in a Post-Dobbs United States
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This study explores how demographic factors and media consumption influence birth control distrust. This research highlights how non-expert content— especially from wellness influencers— shapes perceptions and decisions, particularly among young women shifting from hormonal methods to “natural” alternatives like fertility tracking. The variable measuring distrust in birth control revealed an average score of 1.73, arguing a slight level of distrust. Regression analysis demonstrated that greater reliance on social media was positively associated with a higher distrust in birth control, increased concern over hormonal contraception, and a greater trust in non-experts. These findings align with the Health Belief Model, in the context of social media, often exaggerating hormonal contraception risks while promoting alternative "natural" solutions, reinforcing wellness industry rhetoric. This provides a slippery slope for users as the more modern wellness industry connects to the alt-right. This study and its subsequent findings suggest that social media shapes public perceptions of contraception. Future research should counter misinformation by examining disinformation in minority communities and exploring how the doctor-patient relationship influences susceptibility to birth control propaganda.</p
Biodiversity and Metabolic Pathways in Antarctic Cryoconite Bacteria
Get PDFCryoconite holes are extreme environments that, despite the conditions, host active microbial communities. Canada Glacier in the McMurdo Dry Valleys of Antarctica contains cryoconite holes that form small ecosystems that remain isolated from the atmosphere and from nutrient addition, often for decades at a time. There is much interest in cryoconite holes as a model system for understanding life in the extreme cryosphere, but we know very little about what nutrients are most limiting to cryoconite microorganisms. Here I report on a nutrient addition experiment in realistic microcosms and metagenomic analyses of bacteria that were able to grow in the microcosms to gain a better understanding of how these model systems function as self-contained ecosystems. In contrast to limited information from field studies that indicated phosphorus (P) as the limiting nutrient in cryoconite, I found evidence of a co-limitation by both nitrogen and phosphorus. Genomic analyses of some of the key cryoconite microbes showed that one of the dominant organisms, a Nostoc species, has the genetic capacity to carryout both photosynthesis and nitrogen fixation. The Propionibacterium, Deinococcales, Polarmonas, and Sphingomonadales genomes studied all contained at least one copy of the bacteriorhodopsin gene and therefore may function as photoheterotrophs in this system. The Chloroflexota and Flavobacteria genomes studied did not contain any genes related to phototrophy, and both need further research to explain their metabolic success in cryoconite. Overall, this study provided new insights into how cryoconite microorganisms might be functioning in a model perennially cold, nutrient poor ecosystem.</p
The Versatility of the Drug Dystopia: Tracing Shifting Power Dynamics Through Psychopharmacology
Get PDFThis essay intends to examine two works from consecutive decades, Anthony Burgess’s A Clockwork Orange and Phillip K. Dick’s A Scanner Darkly, that, through their depictions of psychoactive substances, demonstrate the transformation of dialogues on drug use and their intersection with various power structures. This essay argues that those novels’ characterization of their respective regimes and the individuals subjected to them suggests a movement in power away from central governmental organizations toward corporate interests. On the individual level, power remains essentially the same; that is, individuals may possess the appearance of power, yet outside powers fundamentally shape their subjectivity. These portrayals of various power changes constitute a versatile genre capable of innovating social critique as the world changes. Finally, this essay argues that the roots of drug dystopia expose themselves in newer genres, like cyberpunk, suggesting a future direction for the genre.</p
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