Digital Commons Network^™

The Effects Of Multiple Gratitude Interventions Among Informal Caregivers Of Persons With Dementia And Alzheimer's Disease, Cristy Degregory

Theses and Dissertations

The purpose of this group randomized intervention trial was to examine the impact of participation in three telephone-based gratitude interventions on the physical, psychological and social functioning of participants in caregiver support groups who are unpaid family caregivers of persons with dementia and Alzheimer’s disease. Fredrickson’s (2001) Broaden-and-Build Theory informed the investigation of the effect of three gratitude interventions on participants’ levels of gratitude, positive aspects of caregiving, subjective well-being, physical health and mental health. This was a randomized, wait-list controlled study involving informal caregivers involved in support groups. The research questions were: 1.) How does gratitude contribute to subjective …

On The Development Of High Strain Rate Experiments For The Characterization Of Engineering Materials, Silas P. Mallon

Theses and Dissertations

In order to predict the damage accumulation and failure processes associated with highly dynamic events such as blast loading, shock wave loading, and ballistic impact loading, a commensurate understanding of the fundamental constitutive and fracture behavior of materials subjected to such high rate loading conditions is necessary. In this effort, high strain rate experimental facilities consisting of a shock tube apparatus and a torsional split Hopkinson bar apparatus have been designed, constructed, and subsequently used to investigate the mechanical properties of an array of engineering materials subjected to a variety of dynamic loading conditions. Designs for the experimental equipment utilized …

Characterization Of Electrodeposited Copper Foil Surface Roughness For Accurate Conductor Power Loss Modeling, Michael B. Griesi

Theses and Dissertations

As computer data rates have increased, designers observed that the standard models for estimating the impact of copper foil surface roughness on conductor loss are limited to a few GHz. The more recent snowball model (a “snowball” estimation of the Huray Model) has demonstrated improved conductor loss predictions up to 50 GHz by estimating the necessary parameters using reasonable assumptions about the geometric surface features of electrodeposited copper foil. Since then, the Huray Model has been incorporated into commercial electromagnetic field simulators. However, a standard method of characterizing the electrodeposited copper foil used in high-speed circuits to directly implement the …

A Theory Of Reward Stability, Justice Evaluations And Group Cooperation, Hyomin Park

Theses and Dissertations

The objective of this dissertation is to introduce a theory of the stability of rewards, justice evaluations and group cooperation with the results from three empirical tests of the theory. According to justice theory, rewards from exchange relations produce justice evaluations among individuals, leading to emotional and behavioral reactions. Specifically, unjust rewards cause lower levels of justice evaluations, positive emotions, and cooperative behaviors. Prospect theory and research on negativity bias posit the asymmetry between negative and positive events: negative events have a stronger effect than the same size of positive events on individuals’ perception. Combining the previous arguments, the theory …

Analysis Of Hurricane Preparedness Levels And Evacuation Intent For South Carolina Coastal Residents, Wesley Chad Seigler

Theses and Dissertations

Many communities across the nation, especially those in coastal areas, are experiencing extensive growth and expansion. This growth and the associated need for additional infrastructure, goods and services, and basic human needs often place people and the things they value in harm’s way due to the threat of a natural disaster. In order to properly prepare and mitigate disaster impacts, individuals and communities must view disasters as events that will likely occur at least once during their lifetime rather than simply outside possibilities. Residents of coastal communities must prepare for potential impacts from hurricanes and resulting storm surges and must …

Measurement Of Polarization Observables PZ, PSZ, And PCZ In Double-Pion Photoproduction Off The Proton, Yuqing Mao

Theses and Dissertations

Meson production from excited nucleons is important in the study of baryon resonances and pion photoproduction is attracting much attention. To date a rather large amount of unpolarized cross-section measurements have been reported for both single- and double-pion photoproduction. However, polarization observables provide complementary information as they probe different combinations of transition amplitudes. The database for polarization observables remains quite sparse. Double-pion photoproduction have been studied in Hall B at Jefferson Lab with linearly polarized tagged photon beams incident on longitudinally polarized protons. The experiment covered center-of-mass energies between 1.4 GeV and 2.3 GeV. The target was a FROzen Spin …

Determinants Of Cross-Country Differences In The Equity Risk Premium: A Cross-Sectional Analysis, William John Arant

Theses and Dissertations

The equity risk premium (ERP) is a critical factor in financial decision-making and allocating capital for the future. The ERP can indicate the aggregate risk in an economy and thereby the price agents attach to that risk. Understanding the factors that determine ERPs across countries is important for understanding investors’ actions in a globalized environment. This study will focus on long-run measures of the ERP across countries while applying four common measures. Variations in the size of the ERP across countries and across measures will be examined. Then, country-specific determinants of the long-run ERP will be investigated. These determinants include …

Essays On Battle Clusters In Internal Armed Conflicts And Insurgencies: Concept, Causes And Consequences, Chifeng Liu

Theses and Dissertations

With the purpose to re-conceptualize the intensity of internal armed conflicts, I argue that the characteristics such as location, scale and duration of “major battlefields,” i.e. the spatio-temporal clusters of combat events are important in the evaluation of impact of modern civil wars and insurgencies. I start with elaborating and constructing a new concept of conflict magnitude with battle clusters using up-to-date geo-referenced data and spatial statistic methods. In the second article, I first explain the location and duration of major battlefields. The findings indicate that an area with multiple non-state armed groups (NSAGs) is more likely to become main …

Single Nucleotide Polymorphisms In Dna Repair And Oxidative Stress Genes, And Their Interaction With Antioxidants On Prostate Cancer Aggressiveness, Samuel Antwi

Theses and Dissertations

Prostate cancer is the leading invasive malignancy and the second most common cause of cancer death among American men. Despite compelling evidence that oxidative stress, ineffective DNA damage repair, and habitually low antioxidants intake may act in tandem to influence prostate carcinogenesis, few studies have examined gene-diet interactions involving these risk factors. Even fewer studies have examined such interactions in relation to prostate cancer aggressiveness. This study investigated whether single nucleotide polymorphisms (SNPs) in DNA repair- and oxidative stress-related genes modulated associations between antioxidant intake and prostate cancer aggressiveness. We utilized data from the North Carolina-Louisiana Prostate Cancer Project (PCaP) …

Southern Language, Ideology, And Identity In A High School Sorority, Sara Lide

Theses and Dissertations

This dissertation explores the language practices of high school sorority members in a mid-sized city in the U.S. South. Specifically, it describes how economically privileged, white, female youth in the Young Ladies’ Society of Midway (YLSM) used Southern language to position themselves and others in relation to widely and locally circulating ideologies of language, region, gender, and class. Drawing on sociolinguistic and linguistic anthropological methods, this study addresses the issues of how Southern language practices and language ideologies relate and how indexical meanings and social identities emerge through linguistic interaction. As a study that examines the language of a group …

Attention-Deficit/Hyperactivity Disorder And Academic Performance: Student Engagement In The Classroom, Emily B. Mancil

Theses and Dissertations

Youth with Attention/Deficit-Hyperactivity Disorder (ADHD) have many obstacles to positive development (including difficulties in school settings) and are in need of support. However, few studies have focused on the ways in which positive factors, such as student engagement (SE), may be beneficial for this population to identify strategies for supporting their strengths. Although many studies have examined academic and behavioral aspects of SE, few studies have examined the psychological (i.e., teacher-student relationships, peer support for learning, family support for learning) and cognitive (i.e., control and relevance of school work, future aspirations and goals, extrinsic motivation) sub-components of engagement. The current …

Joint Representation Of Translational And Rotational Components Of Self-Motion In The Parietal Cortex, Adhira Sunkara

McKelvey School of Engineering Graduate Student Theses & Dissertations

Navigating through the world involves processing complex visual inputs to extract information about self-motion relative to one's surroundings. When translations (T) and rotations (R) are present together, the velocity patterns projected onto the retina (optic flow) are a combination of the two. Since navigational tasks can be extremely varied, such as deciphering heading or tracking moving prey or estimating one's motion trajectory, it is imperative that the visual system represent both the T and R components. Despite the importance of such joint representations, most previous studies have only focused on the representation of translations. Moreover, these studies emphasized the role …

Aerosol Techniques For Deposition And Characterization Of Biological And Biomimetic Sensitizers For Solar Devices, Vivek B. Shah

McKelvey School of Engineering Graduate Student Theses & Dissertations

Nano-structured columnar films synthesized by the aerosol chemical vapor deposition (ACVD) system are unique, and have proved to be useful for fabricating solar cells and in other applications. The film formation by ACVD process involves three main phenomenon - aerosol formation and growth, deposition, and restructuring. In this work, thin film formation by the ACVD process is simulated by combining three models - (A) particle formation in gas phase by atrimodal model, (B) particle deposition onto heated substrate by a Brownian dynamics model and (C) sintering on the heated substrate by a multi-particle geometric sintering model (MPGSM). Modelling and simulation …

A Reinforcement-Learning Framework For Interpreting Trial-By-Trial Motor Adaptation To Novel Haptic Environments, Ranjan Patrick Khan

McKelvey School of Engineering Graduate Student Theses & Dissertations

Motor adaptation is often considered to occur under the influence of sensory signals, which is usually readily available for humans performing most motor tasks. However, humans can also use reward or other qualitative feedback to reinforce previous actions and perform adaptation. In these experiments, we introduce reward feedback to a traditional motor adaptation experiment: reach adaptation to a velocity-dependent force field. Drawing from the literature of computer science and machine learning, we use a reinforcement-learning framework to interpret the pattern of force generation and reward-prediction errors and observe the effects of concurrent and isolated reward and sensory feedback.

It is …

Approximation And Relaxation Approaches For Parallel And Distributed Machine Learning, Stephen Tyree

McKelvey School of Engineering Graduate Student Theses & Dissertations

Large scale machine learning requires tradeoffs. Commonly this tradeoff has led practitioners to choose simpler, less powerful models, e.g. linear models, in order to process more training examples in a limited time. In this work, we introduce parallelism to the training of non-linear models by leveraging a different tradeoff--approximation. We demonstrate various techniques by which non-linear models can be made amenable to larger data sets and significantly more training parallelism by strategically introducing approximation in certain optimization steps.

For gradient boosted regression tree ensembles, we replace precise selection of tree splits with a coarse-grained, approximate split selection, yielding both faster …

What's Wrong With Me?: An Autoethnographic Investigation Of The Co-Cultural Communicative Practices Of Living With Tourette Syndrome During Adolescence, Mark Congdon Jr.

The Qualitative Report

Using an Autoethnographic methodology, this essay explores how I was diagnosed with Tourette Syndrome. My experience illustrates a dynamic and difficult process of understanding and negotiating assimilation, using a variety of communication strategies related to self-perception, perceptions of others, and interactions with others. Using Co-Cultural theory (CCT) as a theoretical framework, three themes emerged from my experience: (1) nonassertive assimilation: negotiating with relationships of authority, (2) aggressive assimilation: negotiating relationships with peers, and (3) nonassertive separation: the convergence of negotiating relationships of authority and with peers. It is my hope that my story expands the awareness and conversation among and …

The Automatic And Controlled Influence Of Environmental Cues During Recognition Judgments, Diana Selmeczy

Arts & Sciences Graduate Student Theses and Dissertations

Recognition judgments are often made in the context of environmental information, such as instructions or payout regimens that observers have been shown to use in order to adaptively bias their memory judgments. These adaptive biases are usually characterized as a strategic, controlled process that observers adopt intentionally, and this is formalized in signal detection theory wherein strategic criterion placement is assumed fully independent of recognition evidence signals. However, recent pilot research in our laboratory suggests that the ability to regulate recognition decision biases in the context of environmental cues may not be fully controlled by observers suggesting an automatic or …

Origin Of Maternal Age Effect In Congenital Heart Disease Risk For Offspring, Claire Elaine Schulkey

Arts & Sciences Graduate Student Theses and Dissertations

Increasing maternal age is widely acknowledged to lead to greater likelihood of pregnancy complications and congenital abnormalities, but the basis of this effect has not been well studied. Often dismissed as the product of oocyte ageing, the mechanistic basis of this maternal age effect is likely more complex.Congenital heart disease is a classic complex disease with multiple genetic and environmental modifiers, including maternal age. Maternal ageing is a known risk-factor in humans, and has been shown to exist in an Nkx2-5 haploinsufficient mouse model for the disease. This mouse model's maternal age risk is dependent upon strain background, with C57BL/6N …

Real-Time Temperature Imaging Using Ultrasonic Change In Backscattered Energy, Weiyuan Zhao

McKelvey School of Engineering Graduate Student Theses & Dissertations

Thermal therapy from low-temperature cryosurgery to high-temperature ablation of tumors and unwanted electrical pathways has gained increased attention. Temperature imaging (TI) from magnetic resonance studies is the de facto standard for volumetric estimation of temperature. Ultrasound has the advantages of being cheap, portable, non-invasive and non-ionizing. Our group showed in predictions for single scatterers, simulations of scatterer populations and measurements in 1D, 2D and 3D, that CBE changed monotonically with temperature with 1^oC accuracy. An obstacle to clinical application of CBE TI is estimation of temperature in real time, which is limited by time for motion compensation (MC). …

X-Ray Polarimetry With X-Calibur, Qingzhen Guo

Arts & Sciences Graduate Student Theses and Dissertations

ABSTRACT X-Ray Polarimetry with X-Calibur by Qingzhen Guo Doctor of Philosophy in Physics, Washington University in St. Louis, September, 2014. Professor Henric Krawczynski, Chair X-ray polarimetry is a prime tool to investigate the unexplored compact sources and to provide crucial information that other techniques can not produce. By measuring the degree and orientation of the polarization of radiation from a cosmic source, unique inferences about the morphology and the magnetic field structure can be made. Krawczysnki's group at Washington University is working on a uniquely sensitive scattering polarimeter, X-Calibur, to be used in the focal plane of a focusing X-ray …

The Effects Of Gamifying Optional Lessons On Motivation, Aaron Zemach

McKelvey School of Engineering Graduate Student Theses & Dissertations

Adding video-game elements to non-video-game interfaces (“gamification”) has become a common engagement strategy over the past several years in the domain of education. While prior studies have found that adding game elements to mandatory educational materials can increase students’ motivation to complete the materials, there has yet to be a study to investigate if game elements can make users more likely to engage with optional educational materials. In this study, we investigate whether users of a gamified educational interface are more motivated than users of a non-gamified interface to voluntarily complete educational materials. We found users of a gamified interface …

Modeling Algorithm Performance On Highly-Threaded Many-Core Architectures, Lin Ma

McKelvey School of Engineering Graduate Student Theses & Dissertations

The rapid growth of data processing required in various arenas of computation over the past decades necessitates extensive use of parallel computing engines. Among those, highly-threaded many-core machines, such as GPUs have become increasingly popular for accelerating a diverse range of data-intensive applications. They feature a large number of hardware threads with low-overhead context switches to hide the memory access latencies and therefore provide high computational throughput. However, understanding and harnessing such machines places great challenges on algorithm designers and performance tuners due to the complex interaction of threads and hierarchical memory subsystems of these machines. The achieved performance jointly …

Metabolic Engineering Of Cyanobacteria For Photosynthetic Production Of Drop-In Liquid Fuels, Bertram Michael Berla

McKelvey School of Engineering Graduate Student Theses & Dissertations

Cyanobacteria are oxygenic phototrophs with great potential as hosts for renewable fuel and chemical production. They grow very quickly (compared with plants) and can use sunlight for energy and CO2 as a carbon source (unlike yeast or E. coli). While cyanobacteria have been engineered to make many chemicals that are native and non-native parts of their metabolism, this work is concerned with the production of heptadecane in Synechocystis sp. PCC 6803. Heptadecane is in a class of natural products produced by all cyanobacteria, but in quantities insufficient for industrialization. Towards this future goal, we have built enabling systems for the …

A Four-Dimensional Image Reconstruction Framework For Pet Under Arbitrary Geometries, Aswin John Mathews

McKelvey School of Engineering Graduate Student Theses & Dissertations

Positron Emission Tomography (PET) is a functional imaging modality with applications ranging from the treatment of cancer, studying neurological diseases and disease models. Virtual-Pinhole PET technology improves the image quality in terms of resolution and contrast recovery. The technology calls for having a detector with smaller crystals placed near a region of interest in a conventional whole-body PET scanner. The improvement is from the higher spatial sampling of the imaging area near the detector. A prototype half-ring PET insert built to study head-and-neck cancer imaging was extended to breast cancer imaging. We have built a prototype half-ring PET insert for …

Contextualized Robot Navigation, David Vincent Lu

McKelvey School of Engineering Graduate Student Theses & Dissertations

In order to improve the interaction between humans and robots, robots need to be able to move about in a way that is appropriate to the complex environments around them. One way to investigate how the robots should move is through the lens of theatre, which provides us with ways to analyze the robot's movements and the motivations for moving in particular ways. In particular, this has proven useful for improving robot navigation. By altering the costmaps used for path planning, robots can navigate around their environment in ways that incorporate additional contexts. Experimental results with user studies have shown …

The Synchronized Filtering Dataflow, Peng Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

In the past decade, the world has seen the rise of big data, which calls for a paradigm shift in data processing. Streaming processing, where data are processed in their spatial or temporal order, is increasingly common. Meanwhile, parallel computing has become a household term in the computing world. The combination of streaming processing and parallel computing, streaming computing, has been playing an important role in data processing.

A streaming computing system is a network of nodes connected by unidirectional first-in first-out (FIFO) data channels. When a node has multiple input channels, to ensure the deterministic behavior of the whole …

Feeling Doctrine: Religious Meanings Of Emotion In Sixteenth-Century German Literature, Georgia Anna Leeper

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation explores the intersections of emotion and Protestant theology in late-16th-century German literature. The project demonstrates the availability of even secular texts to confessional readings through the analysis of representations of emotions. Post-Reformation texts practice an emotional exemplarity that highlights the effects - including the spiritual effects - which emotional experiences have on the individual. I argue that narrative representations of emotions at this moment reflect anxieties about the nebulous nature of faith, and its central role in Protestant salvation. Close readings of widely-read texts such as the 1587 Faustbuch, Melusine, and Hans Sach's Judith: ein Comedi, among others …

Zinc And Copper Isotopic Fractionation During Planetary Differentiation, Heng Chen

Arts & Sciences Graduate Student Theses and Dissertations

Zinc and copper are two important transition metal elements that are widely involved in every stage of planetary formation and differentiation. Their isotopic ratios are robust tracers used to understand the origin of the Solar System, planetary formation and differentiation processes. In this thesis, I focus on their isotopic behaviors during magmatic processes. I report the Zn isotopic compositions of representative igneous rocks to determine potential isotopic fractionations associated with magmatic processes, and to estimate the bulk silicate Earth value. I report isotopic compositions of various groups of iron meteorites (samples of which represent the core of asteroids) and discuss …

The Late Ordovician Biogeochemical Carbon Cycle, John Garrecht Metzger

Arts & Sciences Graduate Student Theses and Dissertations

The isotopic composition of the carbonate carbon (δ13Ccarb) is one of the best tools for understanding the biogeochemical carbon cycle through Earth history. δ13Ccarb is also used to chemostratigraphically correlate coeval strata. This dissertation has three main foci that all utilize δ13Ccarb as the common data type. The geologic interval investigated was the Late Ordovician (458-444 Ma) with emphasis on the Guttenberg δ13C excursion, a globally correlated, positive ~3 / event that is ~400 kyr in duration. In the first topic we evaluate post-depositional alteration (i.e., diagenesis) of δ13Ccarb signals. In the second topic, we make reconstructions of sea level …

Applications Of Nonlinear Optimization, Yao Xie

Arts & Sciences Graduate Student Theses and Dissertations

We apply an interior point algorithm to two nonlinear optimization problems and achieve improved results. We also devise an approximate convex functional alternative for use in one of the problems and estimate its accuracy. The first problem is maximum variance unfolding in machine learning. The traditional method to solve this problem is to convert it to a semi-definite optimization problem by defining a kernel matrix. We obtain better unfolding and higher speeds with the interior point algorithm on the original non-convex problem for data with less than 10,000 points. The second problem is a multi-objective dose optimization for intensity modulated …