Digital Commons Network^™

Stacking The Gamma-Ray Sky To Search For Faint Astrophysical Populations, Yuzhe Song

Dissertations, Theses, and Capstone Projects

Gamma-ray emission can be generated from a wide variety of high-energy astrophysical phenomena, from stellar flares to pulsating neutron stars, and from interstellar clouds to the center of the Milky Way Galaxy. Entering the 13th year of its orbit around Earth, the Fermi Space Gamma-ray Telescope has been continually surveying the γ-ray sky with its Large Area Telescope (LAT) on board. The latest Fermi source catalog contains over 6000 sources. Yet, a lot of sources that are expected to emit γ-rays are not detected, and only small percentages of some populations are detected. For example, solar flares are detected in …

Towards Explaining Variation In Entrainment, Andreas Weise

Dissertations, Theses, and Capstone Projects

Entrainment refers to the tendency of human speakers to adapt to their interlocutors to become more similar to them. This affects various dimensions and occurs in many contexts, allowing for rich applications in human-computer interaction. However, it is not exhibited by every speaker in every conversation but varies widely across features, speakers, and contexts, hindering broad application. This variation, whose guiding principles are poorly understood even after decades of entrainment research, is the subject of this thesis. We begin with a comprehensive literature review that serves as the foundation of our own work and provides a reference to guide future …

Engineering Rare-Earth Based Color Centers In Wide Bandgap Semiconductors For Quantum And Nanoscale Applications, Gabriel I. López-Morales

Dissertations, Theses, and Capstone Projects

For many years, atomic point-defects have been readily used to tune the bulk properties of solid-state crystalline materials, for instance, through the inclusion of elemental impurities (doping) during growth, or post-processing treatments such as ion bombardment or high-energy irradiation. Such atomic point-defects introduce local ‘incompatible’ chemical interactions with the periodic atomic arrangement that makes up the crystal, resulting for example in localized electronic states due to dangling bonds or excess of electrons. When present in sufficient concentrations, the defects interact collectively to alter the overall bulk properties of the host material. In the low concentration limit, however, point-defects can serve …

Facing The Fringe, Laura Gradowski

Dissertations, Theses, and Capstone Projects

Fringe theories are a broad set of alternative views that mainstream scientists deny. Case studies from the past two centuries demonstrate that fringe theorists have sometimes been marginalized to the detriment of scientific advancements. While it is accepted that once in a blue moon comes a diamond in the rough, there are far more cases of fringe theories becoming mainstream than has been traditionally acknowledged. Indeed, fringe theories become mainstream with such regularity that our epistemic intolerance towards them is in need of urgent reexamination. With the recognition that tolerance is an epistemic virtue, we can view debates about theory …

Growth, Optimization, And Characterization Of Topological Insulator Nanostructures By Molecular Beam Epitaxy, Ido Levy

Dissertations, Theses, and Capstone Projects

Topological insulators (TIs) have been the subject of much research since their discovery in 2009. The unique band structure of the TIs makes them attractive in research of exotic physical phenomena, such as the realization of the quantum anomalous Hall effect, as well as novel applications, including quantum computing, spintronics, and more. From a crystal growth perspective, their van-der-Waals structure also provides new opportunities, for example, by enabling the growth on a large selection of substrates. This thesis presents the growth of three-dimensional TI layers, heterostructures and magnetic TIs by molecular beam epitaxy (MBE). First, we show the improvement of …

Decolonizing Genderqueer: An Inquiry Into The Gender Binary, Resistance, And Imperialistic Social Categories, Lauren E. Abruzzo

Dissertations, Theses, and Capstone Projects

This dissertation examines core metaphysical properties of nonbinary and genderqueer categories in dominant U.S. contexts. I address a prevailing argument that these categories, by definition, resist the gender binary and are therefore radical modes of existing. In response, I put forth a view of ‘nonbinary’ and ‘genderqueer’ that I call the Diachronic Approach, which describes these categories as yet another set of tools within an imperialistic gender system, much like ‘man’ or ‘woman.’ In other words, they are what I refer to as imperialistic social categories. While nonbinary and genderqueer people do not fall perfectly within the U.S. gender …

Dynamics Of Cubic Rational Maps Under Certain Constraints On Critical Points, Arkady Etkin

Dissertations, Theses, and Capstone Projects

There is a neat dichotomy for the Julia sets of quadratic rational maps; that is, they are either connected or a Cantor set. In contrast to the quadratic case, the Julia sets of rational maps of of degree ≥ 3 have more variations. In this project, we study the Julia sets of cubic rational maps under some constraints. We first extend the Julia set dichotomy to the cubic rational maps with all critical points escaping to an attracting fixed point. Then we consider two more classes of cubic rational maps: one class consists of the cubic rational maps with two …

Pervasive Nonarbitrariness: Meaning From Form In Natural Language, David J. Neely

Dissertations, Theses, and Capstone Projects

It is generally assumed that the expressions of a natural language are largely arbitrary. That is, any expressions that display a nonarbitrary connection between what their utterances sound like and what they mean are small in number and of no real theoretical importance.

This thesis challenges such a position. I argue that nonarbitrariness is a pervasive feature of natural language and that understanding the sound/meaning connections that exist in language is necessary if to appreciate how languages work.

I begin, in Chapter 1, by showing that many theorists are committed to the idea that nonarbitrary sound/meaning connections are of little …

High Water-Responsiveness Of Peptidoglycan And Its Water-Responsive Mechanism, Haozhen Wang

Dissertations, Theses, and Capstone Projects

Water-responsive materials that reversibly deform in response to humidity changes show great potential for developing muscle-like actuators for miniature and biomimetic robotics. This thesis demonstrates that peptidoglycan exhibits ultrahigh water-responsive actuation energy and power densities, which are orders of magnitude higher than those of frequently used actuators, such as piezoelectric actuators and dielectric elastomers. Surprisingly, peptidoglycan exhibits an energy conversion efficiency of ~66.8%, which could be attributed to its super-viscous nanoconfined water that efficiently translates water’s movement to peptidoglycan’s mechanical deformation. The systematic water-responsive characterizations of peptidoglycan from different microorganisms and peptide crystals indicate that enhanced H-bonding interactions in water-responsive …

Nmr Characterization Of Novel Materials For Battery Electrolyte Applications, Sahana Bhattacharyya

Dissertations, Theses, and Capstone Projects

The extensive application of renewable and non-renewable energy storage devices in commercial products and services and the global warming have created significant motivations to accelerate research in battery technology. In addition, the risk factors generated by the high heat generation and flammability of the batteries are being addressed by inventing new renewable or non-renewable energy resources that do not release greenhouse gases into the atmosphere. This thesis discusses the applications of Nuclear Magnetic Resonance (NMR) Spectroscopy in characterizing and understanding novel battery materials as potential battery electrolytes. Works discussed include: the variable temperature characterization of water-based solid polymer electrolyte for …

The Persistence Of Exclusion In Developmental Math Courses In Community Colleges: The Search For Equity And Justice In Math Education, Dora P. Trujillo

Dissertations, Theses, and Capstone Projects

This study examines how minoritized community college students taking developmental mathematics courses construct their math identities and how structures within academia affect this construction. It uses interviews and a focus group with open-ended questions to look beyond the quantitative studies examining the effectiveness of math developmental courses by exploring student narratives rather than statistical data. Both curricula and pedagogies need to be de-constructed so we may bring social change through diversity to the teaching and learning of mathematics at this level, as developmental math courses have become a systematized form of marginalization. In the process of de-constructing, we also need …

Play: A Normative Theory Of Agency And Culture, Maxaie Belmont

Dissertations, Theses, and Capstone Projects

From the beginning, people are introduced to many different attempts at engaging with various “cultures”, and of course, are born into their own. The extant literature of various fields in the social sciences have afforded us the realization that no one culture holds neither moral ground nor blueprint for how to be a culture, as our own culture is one of many, all a part of the world. Yet, because of the way our culture specifies how we are to engage and live, we tend towards the assumption that our culture has monopoly on the definition of culture. The following …

Grammar Competition Explored In Two Case Studies: The Null Subject Stage In English-Speaking Children And The Variation Observed In Old English, Soumik Dey

Dissertations, Theses, and Capstone Projects

Grammar competition theory postulates that variation in a speaker is the result of different grammars competing against each other. This study performs an analysis of two case studies of empirical observations attributed to possible grammar competition — subject drop in English-speaking children and variation observed in Old English.

Children in an English-speaking environment drop subjects early on during acquisition. Orfitelli and Hyams (2012) find that young English-speaking children mistakenly interpret imperative null subject utterances as declaratives. They suggest that this misinterpretation can be attributed to performance factors, which leads to grammar competition and subsequently subject drop in English children. We …

Using Protonation Microstates And Hydrogen Bond Networks To Track Proton Transfer Pathways In Complex I, Umesh Khaniya

Dissertations, Theses, and Capstone Projects

Complex I, NADH-ubiquinone oxidoreductase, is the first enzyme in the mitochondrial and bacterial aerobic respiratory chain. It pumps four protons through four transiently open pathways from the high pH, negative, N- side of the membrane to the positive, P-side driven by the exergonic transfer of electrons from NADH to a quinone. Three protons transfer through subunits descended from Mrp antiporters, while the fourth, E-channel is unique. Because of the complex possible paths thorough the many buried polar residues and lack of high-resolution crystal structure, the path for protons through the E-channel is elusive.

In this dissertation, the E-channel proton pumping …

An Analysis Of The Friendship Paradox And Derived Sampling Methods, Yitzchak Novick

Dissertations, Theses, and Capstone Projects

The friendship paradox (FP) is the famous sampling-bias phenomenon that leads to the seemingly paradoxical truth that, on average, people’s friends have more friends than they do. Among the many far-reaching research findings the FP inspired is a sampling method that samples neighbors of vertices in a graph in order to acquire random vertices that are of higher expected degree than average.

Our research examines the friendship paradox on a local level. We seek to quantify the impact of the FP on an individual vertex by defining the vertex’s “friendship index”, a measure of the extent to which the phenomenon …

The Separation Of Charm And Bottom Decays Measured In P+Au Collisions At 200 Gev, Zhiyan Wang

Dissertations, Theses, and Capstone Projects

It has long been observed experimentally, from previous heavy-flavor electron measurements, that heavy quarks are subject to substantial modifications of their momentum spectrum. Using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC), measurements of the production of open heavy flavor hadrons with charm and bottom quarks in p+Au collisions at 200 GeV are studied and presented in this thesis. Distance of closest approach analysis of electron tracks is used to study the semileptonic decay electrons from charm and bottom hadrons. The results include invariant yield and fraction of bottom electrons. In addition to the p+p and Au+Au collisions’ …

Bitrdf: Extending Rdf For Bitemporal Data, Di Wu

Dissertations, Theses, and Capstone Projects

The Internet is not only a platform for communication, transactions, and cloud storage, but it is also a large knowledge store where people as well as machines can create, manipulate, infer, and make use of data and knowledge. The Semantic Web was developed for this purpose. It aims to help machines understand the meaning of data and knowledge so that machines can use the data and knowledge in decision making. The Resource Description Framework (RDF) forms the foundation of the Semantic Web which is organized as the Semantic Web Layer Cake. RDF is limited and can only express a binary …

Learning Beyond Measure: Critical Numeracy And Resistance To Racial Capitalism, Atasi Das

Dissertations, Theses, and Capstone Projects

In this three-article dissertation, I connect with and expand from learning theories and mathematics and numeracy practices to reimagine numeracy as a potential tool towards liberation and human emancipation. Developing a framework and activity of critical numeracy, I explore the ways numbers and static categories have been used to “objectively” create, reproduce, and reify hierarchies within historical contexts and power relations. The core of this work examines, what do numbers and numeracy mean for us? Who are “the us” we can organize for? And for what purpose can and should we utilize, teach, and learn with numbers in and beyond …

Driven Dipolaritons In Van Der Waals Transition Metal Dichalcogenide Heterostructures: Properties And Applications, Patrick Serafin

Dissertations, Theses, and Capstone Projects

The need for advances in optical computation leads us toward the investigation of novel methods of re-routing light in optical circuits. The behavior and properties of electrically driven exciton-dipolaritons in van der Waals transition metal dichalcogenides are investigated as a platform for realizing working elements of a polaritronic transistor. In this work, we consider exciton-dipolaritons, which are three-way superposition of cavity photons, direct excitons, and indirect excitons in a bilayer semiconducting system embedded in an optical microcavity. We start by providing motivation for our study of polaritons and then survey the fundamental properties of exciton-dipolaritons. We also survey the basic …

Sensitized Photooxidation Of Prenylated Compounds: Mechanisms Of Downstream Dark Effects And Phototoxicity Priming, Shakeela Jabeen

Dissertations, Theses, and Capstone Projects

This thesis consists of four chapters as detailed below.

Chapter 1 discusses a singlet oxygen priming mechanism. Airborne singlet oxygen derived from photosensitization of triplet dioxygen is shown to react with an alkene surfactant (8-methylnon-7-ene-1 sulfonate) leading to ‘ene’ hydroperoxides that in the dark inactivate planktonic E. coli. The ‘ene’ hydroperoxide photoproducts are not toxic on their own, but they become toxic after the bacteria are pretreated with singlet oxygen. The total quenching rate constant (k_T) of singlet oxygen of the alkene surfactant was measured to be 1.1 × 10⁶ M⁻¹ s^{− …}

Intelligence Testing In The New (Langu)Age: Effects Of Item-Type And Assessment Medium Features On Fluid Intelligence Test Linguistic Group Score Differences, Paige R. Alenick

Dissertations, Theses, and Capstone Projects

As fluid intelligence tests are an integral part of modern employee selection protocols, assessment designers are tasked to ensure the construct is measured accurately for all test-takers regardless of their demographic traits. Disparities in bilingual and monolingual working memory capabilities, which are critical for successful fluid intelligence test performance, might make it challenging for test designers to accomplish this goal. Best design practice in such cases is to identify assessment conditions that allow for equitable expression of the test construct. Thus, the purpose of this study was to examine whether the content of items present on a fluid intelligence test …

Influence Level Prediction On Social Media Through Multi-Task And Sociolinguistic User Characteristics Modeling, Denys Katerenchuk

Dissertations, Theses, and Capstone Projects

Prediction of a user’s influence level on social networks has attracted a lot of attention as human interactions move online. Influential users have the ability to influence others’ behavior to achieve their own agenda. As a result, predicting users’ level of influence online can help to understand social networks, forecast trends, prevent misinformation, etc. The research on user influence in social networks has attracted much attention across multiple disciplines, from social sciences to mathematics, yet it is still not well understood. One of the difficulties is that the definition of influence is specific to a particular problem or a domain, …

Nutrient Dynamics And Ecosystem Development Of Urban Forests, Gisselle A. Mejía

Dissertations, Theses, and Capstone Projects

Urban growth and expansion are a major component of global environmental change, with impacts on climate, air and water quality, biodiversity, and human well-being. Forests embedded in urban landscapes are critical in mitigating these impacts at local, regional, and continental scales. However, assessing urban forests is difficult because cities are heterogenous in physical, chemical, biological, and social dimensions. This heterogeneity has constrained how urban forests are defined, and therefore, how they are studied. The objective of this dissertation is to determine how these biophysical and social factors drive ecological processes in urban forests and will address three outstanding challenges in …

Transforming Afterschool Programs Into "Engines Of Development": A Policy Analysis Of The Federal 21st Century Community Learning Centers, Jane Quinn

Dissertations, Theses, and Capstone Projects

Although schools receive most of the attention in discussions of and research about educational policy, an equally important—and under-investigated—arena is the non-school hours. American students spend more time outside of school than in school, and a host of studies have shown that the ways young people spend their discretionary time can greatly influence their short-term and long-term outcomes. Issues of educational equity are deeply embedded in the topic because opportunities to participate in high quality out-of-school learning experiences are not evenly distributed in American society. The single most important policy target in this aspect of student life is the federal …

Astrophysics, Cosmology And Particle Phenomenology At The Energy Frontier, Jorge Fernandez Soriano

Dissertations, Theses, and Capstone Projects

This dissertation consists of two parts, treating significantly separated fields. Each part consists on several chapters, each treating a somewhat isolated topic from the rest. In each chapter, I present some of the work developed during my passage through the graduate program, which has mostly been published elsewhere.

Part I – Cosmic Rays and Particle Physics

• Chapter 1: In this chapter we present an introduction to the topic of cosmic ray physics, with an special focus on the so-called ultra high energy cosmic rays: their potential origins, effects during their propagation between their sources and Earth, the different techniques used …

The Storytelling Cure: Medicine And Narrative From Galen To Shahrazad And Rousseau, Ryan A. Milov-Cordoba

Dissertations, Theses, and Capstone Projects

Are stories healing? This dissertation introduces and explores an idea that I call “the storytelling cure.” With this term I capture a set of related notions about the healing power of stories that span literary studies, intellectual history, philosophy, and medical practice. Through a comparative study I make the case for “the storytelling cure” as a cross-cultural, multiconfessional, and multilingual phenomenon of great age, complexity, and power, worthy of the most sustained attention by the contemporary field of Comparative Literature. Concretely, this dissertation presents three extended case studies of “storytelling cures” from three different kinds of texts (case history, frame …

The Microscopical Evidence Traces Analysis Of Household Dust And Its Statistical Significance As A Definitive Identification Technique, Stephanie Polifroni

Dissertations, Theses, and Capstone Projects

Evidence found at crime scenes is used to assist in creating a link the suspect, the victim, and the scene. As stated by the Locard’s Principle, every contact leaves a trace, that evidence can be used to link together an investigation. Traces are collected in hopes that they can be identified and associated to an individual or individuals to help solve that particular crime. However, the strongest conclusion for evidence traces is an association to a source, and unless a physical match of some kind is found, an individualization cannot be established even when known sample is available. However, having …

Control Of Nonlinear Properties Of Van Der Waals Materials, Rezlind Bushati

Dissertations, Theses, and Capstone Projects

Van der Waals materials are a broad class of materials that exhibit unique optoelectronic properties. They provide a rich playground for which they can be integrated into current on-chip devices due to their nanometer-scale size, and be utilized for studying fundamental physics. Strong coupling of emitters to microcavities provides many opportunities for new exotic physics through the formation of hybrid quasi-particles exciton-polaritons. This thesis
focuses on exploring and enhancing nonlinearity of van der Waals materials through strongly coupling to microcavities. By taking advantage of the stacking order of TMDs, we show intense second-harmonic generation from bulk, centrosymmetric TMD systems. In …

The Local Lifting Problem For Curves With Quaternion Actions, George Mitchell

Dissertations, Theses, and Capstone Projects

The lifting problem asks whether one can lift Galois covers of curves defined over positive characteristic to Galois covers of curves over characteristic zero. The lifting problem has an equivalent local variant, which asks if a Galois extension of complete discrete valuation rings over positive characteristic, with algebraically closed residue field, can be lifted to characteristic zero. In this dissertation, we content ourselves with the study of the local lifting problem when the prime is 2, and the Galois group of the extension is the group of quaternions. In this case, it is known that certain quaternion extensions cannot be …

Magnetic Field Effects On The Physics Of Neutron Stars, Aric A. Hackebill

Dissertations, Theses, and Capstone Projects

In the context of neutron stars (NS), dense-magnetized quark and hadron models have been well studied under the assumption that the system's pressures are isotropic. However, the pressures determined from semi-classical statistical averaging of the energy momentum tensor in the presence of a uniform background magnetic field are anisotropic with different pressures arising along and perpendicular to the magnetic field direction. Since large magnetic fields are expected to be present in the interior of NS, it is important to understand the roll the pressure anisotropy plays. While considering the pressure anisotropy, we revisit some important calculations in NS physics.

We …