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Quantum electrodynamics of non-Hermitian Dirac fermions
No full textAbstract
We develop an effective quantum electrodynamics for non-Hermitian (NH) Dirac materials interacting with photons. These systems are described by nonspatial symmetry protected Lorentz invariant NH Dirac operators, featuring two velocity parameters υH and υNH associated with the standard Hermitian and a masslike anti-Hermitian Dirac operators, respectively. They display linear energy-momentum relation, however, in terms of an effective Fermi velocity
υ
F
=
υ
H
2
‚àí
υ
NH
2
of NH Dirac fermions. Interaction with the fluctuating electromagnetic radiation then gives birth to an emergent Lorentz symmetry in this family of NH Dirac materials in the deep infrared regime, where the system possesses a unique terminal velocity υF = c, with c being the speed of light. While in two dimensions such a terminal velocity is set by the speed of light in the free space, dynamic screening in three spatial dimensions permits its nonuniversal values. Manifestations of such an emergent spacetime symmetry on the scale dependence of various physical observables in correlated NH Dirac materials are discussed.</jats:p
Properties of the Global Solutions of a Two-Dimensional Incompressible Dissipative Quasi-Geostrophic Equation
No full textWe consider a 2D quasi-geostrophic equation. We prove the existence of global smooth solution and weak solution to the Cauchy problem of this equation by using energy estimate. We also establish the elementary decay estimates and the primary decay estimate with sharp rate, the exact limits for all order derivatives of the global weak solutions to a two-dimensional incompressible dissipative quasi-geostrophic equation. We will consider our case for the initial function and the external force. We will couple together existing ideas (including the Fourier transformation and its properties, Parseval\u27s identity, iteration technique, Lebesgue\u27s dominated convergence theorem, Cauchy-Schwartz\u27s inequality, etc) existing results (the existence of global weak solutions)</p
Flux Compactifications and Intersecting Sources
No full textWhen discussing the expansion of the universe, we often use a scalarpotential as a model. To build this type of model, one can use flux
compactifications in type IIB string theory. In the introduction of this
thesis, we cover this and other relevant concepts. Then, in the next section,
we discuss our work in [5], where we examine a nongeometric model and
discuss the local minima of its associated scalar potential. Finally, in the
last section, we look at our work in [6], where we study the intersection
between two higher dimensional objects in string theory, known as D-branes
or O-planes. The intersection of these objects in string theory are of interest
when building models of particle physics and for flux compactifications.</p
Degradation of Bioactive Peptides by Exopeptidases Influences Cell Behavior
No full textBiomaterials act at the interface of biology to enhance, impart, or recapitulate function to biologic systems. Incorporation of bioactive peptides within these materials is often necessary to improve function, however, the stability of these peptides is often unclear. Current methods of peptide quantification are laborious, and are mostly designed to test one substrate, or one protease at a time. A more functional assay capable of quantifying peptide stability in the presence of cells, with all the proteases and inhibitors that cells produce is needed to better understand cell-material interactions. Presented in this thesis is a novel liquid chromatography – mass spectrometry (LC-MS) based assay capable of multiplex quantification of peptides in the presence of cells and all the proteases they excrete. Medium is sampled and directly injected into the LC-MS to maintain sample integrity, at the cost of chromatography column lifespan. This method was used show simple chain-end modifications to peptides provides the most control over non-specific degradation of those peptides. Also, a novel N-terminal acetylated β-alanine was shown to impart the most protection against non-specific aminopeptidases. Additionally, data to support the theory that non-specific degradation of peptides tethered to biomaterials influence cell behaviorThis work 1) develops new LC-MS based analytical techniques quantification of peptide stability in the presence of cells, 2) using RGEFV as a model peptide, demonstrate the importance of chain-end chemistry on peptide fidelity, and 3) demonstrate that non-specific degradation of peptides incorporated into hydrogels influences biological performance. Our results show that N-terminal amines were almost completely degraded in the presence of hMSCs, hUVECs, and Macrophages by 48 hours of culture independent of the terminal amino acid. Peptides with C-terminal carboxylic acids were also mostly degraded independent of terminal amino acid. However, simple chain-end modifications may prevent non-specific degradation of peptides, preserving function.</p
The Painful Ambivalence of Passing: Negotiating mixed-raced Identity in The Autobiography of an Ex-Colored Man
No full textThis work looks at James Weldon Johnson’s The Autobiography of an Ex-Colored Man to accentuate Johnson’s nuanced, complex portrayal of passing as an intergenerational strategy for survival amid white supremacy. In doing so, I complicate criticism that has perceived passing as selfish, individualistic, and merely an expression of internalized racism in order to revisit passing narratives for their contemporary relevance. Toward this end, this paper looks at the violent racialization of the novel’s narrator in childhood, his decision to pass, and the intergenerational complexities of passing. Johnson’s empathetic representation invites us to think Afrodiasporically, to trace long histories of assimilationist practices among people of African descent past and present, and to consider the consequences of these assimilationist behaviors. This paper also analyzes the Afrodiasporic vision cast by Johnson of Jacksonville, Florida as a utopian space of interethnic Black community, which Johnson represents as uniquely capable of enabling mixed-race people to live affirmatively in their blackness. </p
Life Cycle Analysis of High-Volume Replacement of Ordinary Portland Cement in Precast Concrete to Quantify Carbon Footprint Reductions Using Cradle-to-Gate Boundaries
No full textSince the dawn of the industrial age, the amount of anthropogenic green house gas emissions has increased exponentially. This phenomenon has been linked to global warming of the earth and consequentially a change to its climate. This has caused an increase in awareness of the environmental impacts of products used in daily life, chief among these is concrete. Concrete is the most consumed product on the planet. As the world develops, concrete is needed to build housing, schools, businesses, etc. Suffice to say, we cannot simply phase out concrete, meaning a reduction of footprint must occur. In order to quantify the environmental footprint and subsequent reduction of emissions, a proper Life Cycle Analysis (LCA) must take place. For this particular project the team proposed using fly-ash as a Supplementary Cementitious Material (SCM) to replace Ordinary Portland Cement (OPC). The goal of this was to provide evidence that the proposed forty percent replacement of OPC with fly-ash SCM reduced emissions over zero replacement and current maximum allowed replacement levels. The team\u27s LCA found that the proposed concrete mixture designs reduced environmental footprints forty-two percent and twenty-two percent over no replacement and maximum replacement mixtures accordingly. The work pairs with recent decisions by regulatory bodies to begin regulating based on embodied carbon instead of the traditional emissions regulations
Systematic Review of AI Ethics Education for K-12 and Higher Education
No full textSystematic review of AI ethics education in K-12 and higher education to uncover themes, challenges, and teaching practices.This project focuses on conducting a systematic review of AI ethics education for K-12 and higher education, addressing the critical gap in understanding the current state of teaching AI ethics. With the rapid integration of AI into daily life, there is an increasing need to ensure that students not only grasp fundamental AI concepts but also develop the ethical awareness necessary to responsibly use and create AI technologies. This project how and what AI ethics topics have been introduced in educational contexts. Currently, I am in the data extraction stage of the project. This involves systematically reviewing and coding data from selected peer-reviewed articles using a comprehensive coding scheme. This coding scheme has been iteratively refined to capture education motivation, key topics, instructional strategies, program types, and challenges associated with AI ethics education. The outcomes of this systematic review will provide valuable insights into existing AI ethics curricula and their implementation across diverse educational settings. These findings will serve as a foundation for designing improved AI ethics education frameworks, informing educators, policymakers, and researchers on how to foster ethical awareness among students.</p
Generative AI and Ethical Boundaries for Multilingual Writers - Project Summary
No full textThis research explores how writing teachers\u27 and multilingual students\u27 use of AI can shape their perceptions of ethics in composition.Multilingual English students often encounter difficulty writing research in English. In their first year, they must develop sufficient proficiency to attribute words and ideas to other sources, while learning the culturally defined ethical binaries regarding originality vs. plagiarism. A coping strategy for them is to use AI tools to explore how to write, and how to use feedback to revise. But where is the boundary between using AI to promote vs. replace learning? And how does using AI shape students\u27 perceptions of their own writing processes? To address these two questions, an exploratory ethnographic study following a group of multilingual students in their first year at university in writing courses (fall and spring semesters 2024-2025) is needed, a course where teachers guide students in AI use. The current research involves pre/post-instruction surveys and writing samples, class observations, analysis of student essays, and discussion groups to explore teacher\u27s instructional use of generative AI and its impact on freshman students\u27 perceptions of and engagement with the writing process. The intended outcome of the present research is a list of 8-10 effective class writing activities using AI with explanations and suggestions for composition teachers to consider