Physical Sciences and Mathematics Commons^™

Evolutionary Dynamics Of Speciation And Extinction, Dawn Michelle King

Dissertations

Presented here is an interdisciplinary study that draws connections between the fields of physics, mathematics, and evolutionary biology. Importantly, as we move through the Anthropocene Epoch, where human-driven climate change threatens biodiversity, understanding how an evolving population responds to extinction stress could be key to saving endangered ecosystems. With a neutral, agent-based model that incorporates the main principles of Darwinian evolution, such as heritability, variability, and competition, the dynamics of speciation and extinction is investigated. The simulated organisms evolve according to the reaction-diffusion rules of the 2D directed percolation universality class. Offspring are generated according to one of three reproduction …

Design Of Oppnet Virtual Machine For Opportunistic Resource Utilization Networks: A Universal Standard For Application-Level Resource Sharing, Mai A. Alduailij

Dissertations

Opportunistic resource utilization networks or oppnets are a paradigm for specialized ad hoc networks. The Oppnet Virtual Machine (OVM) is a collection of primitives designed to create a middleware for application-level resource acquisition by oppnets and oppnet-enabled systems and devices (where the latter are defined as the computational entities able to communicate with other oppnets or oppnet-enabled entities). Acquisition of communication resources is the foundation for acquisition of other resources.

The OVM primitives can be downloaded by any computational entity—making entity oppnet-enabled. OVM ensures that oppnet-enabled entities can communicate and acquire resources in an opportunistic and ad hoc manner. This …

Deposition And Characterization Of Carbon Nanotubes (Cnts) Based Films For Sensing Applications, Amila C. Dissanayake

Dissertations

The advent of carbon nanotubes (CNTs) has opened up lot of novel applications because of their unique electrical and mechanical properties. CNTs are well known material for its exceptional electrical, mechanical, optical, thermal and chemical properties. A single-wall nanotube (SWNT) can be either semiconducting, metallic or semi-metallic, based on its chirality and diameter. SWNTs can be used in transistor device as active channels due to high electron mobility (~10000 cm2/(V s), electrical interconnects, nano-scale circuits, field-emission displays, light-emitting devices and thermal heat sinks due to low resistivity, high current density (~109A cm-2) and high thermal conductivity (~3500 W m-1). Further, …

Design And Synthesis Of New Non-Steroidal Anti-Inflammatory Drugs With Anti-Cancer Activity On Colon Rectal Cancer Cell Lines Hct-116 And Caco-2, Wanda Ivette Rodríguez Rivera

Dissertations

Colon rectal cancer is one of the most common types of cancer and is the third leading cause of cancer related deaths among western countries. Current chemotherapy treatments are highly toxic and mostly result in only a low percentage of tumor reduction; therefore an effective treatment with low toxicity is needed.

In this study, different innovative new COX-2 inhibitors were synthesized using the frame of biologically active chalcones to which active COX-2 pharmacophores SO₂CH₃, SO₂NH₂, SO₂NHCOCH₃ were added. Additionally, the effect of different alkyl chain lengths and the effect …

Rank Based Procedures For Ordered Alternative Models, Yuanyuan Shao

Dissertations

The ordered alternatives in a one-way layout with k ordered treatment levels are appropriate for many applications, especially in psychology and medicine. There is extensive literature in this area, and many parametric and nonparametric approaches have been introduced. Abelson-Tukey (AT) test is a frequently used parametric method. Its coefficients provide an ideal way of combining means for the purpose of detecting a monotonic relationship between the independent and dependent variables. The AT method, though, is not robust. Furthermore, our initial empirical studies show that it is not more powerful than the Jonckheere-Terpstra (JT) and the Hettmansperger- Norton (HN) nonparametric tests …

Novel Software Defined Radio Architecture With Graphics Processor Acceleration, Lalith Narasimhan

Dissertations

Wireless has become one of the most pervasive core technologies in the modern world. Demand for faster data rates, improved spectrum efficiency, higher system access capacity, seamless protocol integration, improved security and robustness under varying channel environments has led to the resurgence of programmable software defined radio (SDR) as an alternative to traditional ASIC based radios. Future SDR implementations will need support for multiple standards on platforms with multi-Gb/s connectivity, parallel processing and spectrum sensing capabilities. This dissertation implemented key technologies of importance in addressing these issues namely development of cost effective multi-mode reconfigurable SDR and providing a framework to …

Identities And Motives Of Naturalist Development Program Attendees And Their Relation To Professional Careers, Jennifer A. Mraz

Dissertations

In recent years, there has been much concern over the decline of biologists who actually identify themselves to be naturalists, which negatively impacts the field of conservation and the study of biology as a whole. This could result in a decrease in individuals who participate in naturalist-like activities, such as informal environmental education and environmental volunteerism. The purpose of my study was to determine what discourse identities were held by naturalist development program participants, how these discourse identities related to their volunteer motives in environmental settings, and how discourse identity related to professional careers. I defined identity through the lens …

Hybrid Aryl-Ether-Ketone And Hyperbranched Epoxy Networks, John Misasi

Dissertations

In this dissertation, relationships between chemical structures, cure kinetics and network architectures are correlated to bulk mechanical properties for novel, hybrid epoxy-amine networks. The work is split into two primary sections: the first is the synthesis and characterization of multifunctional glassy networks based on aryl-ether-ketone diamine curatives, while the second is based on the synthesis and characterization of hyperbranched epoxy polymers and their resulting networks.

Three aryl-ether-ketone (AEK) diamines of increasing molecular weights were synthesized and used to cure 4,4’-tetraglycidylether of diaminodiphenylmethane (TGDDM); the resulting networks were compared to 4,4’-diaminodiphenyl sulfone cured TGDDM. Architectural differences were created by varying cure …

Olfactory Enrichment In California Sea Lions (Zalophus Californianus), Mystera M. Samuelson

Dissertations

In the wild, California sea lions (Zalophus californianus) are exposed to a wide array of sensory information at all times. However, it is impossible for captive environments to provide this level of complexity. Therefore unique procedures and practices are necessary for the maintenance of physiological and psychological health in captive animals (Wells, 2009). This project aims to explore the behavioral effect of scent added to the environment, with the goal of improving the welfare of captive sea lions by introducing two scent types: 1.) Natural scents, found in their native environment, and 2.) Non-natural scents, not found in …

Macrobenthic Communities In The Northern Gulf Of Mexico Hypoxic Zone: Testing The Pearson-Rosenberg Model, Shivakumar Shivarudrappa

Dissertations

The Pearson and Rosenberg (P-R) conceptual model of macrobenthic succession was used to assess the impact of hypoxia (dissolved oxygen [DO] ≤ 2 mg/L) on the macrobenthic community on the continental shelf of northern Gulf of Mexico for the first time. The model uses a stress-response relationship between environmental parameters and the macrobenthic community to determine the ecological condition of the benthic habitat. The ecological significance of dissolved oxygen in a benthic habitat is well understood. In addition, the annual recurrence of bottom-water hypoxia on the Louisiana/Texas shelf during summer months is well documented.

The P-R model illustrates the decreasing …

Development Of Dual-Cure Hybrid Polybenzoxazine Thermosets, Jananee Narayanan Sivakami

Dissertations

Polybenzoxazines are potential high performance thermoset replacements for traditional phenolic resins that can undergo an autocatalytic, thermally initiated ring - opening polymerization, and possess superior processing advantages including excellent shelf-life stability, zero volatile loss and limited volumetric shrinkage. The simplistic monomer synthesis and availability of a wide variety of inexpensive starting materials allows enormous molecular design flexibility for accessing a wide range of tailorable material properties for targeted applications. Despite the fact, once fully cured, benzoxazines are difficult to handle due to their inherent brittleness, leaving a very little scope for any modifications. The motivation of this dissertation is directed …

Hydrogen Bond-Mediated Structural Order In Hydroxylated Bis-Mpa Dendritic Polymers: Experimental And Molecular Dynamics Simulation Study, Maliha N. Syed

Dissertations

Dendritic architectures are echoed throughout nature. While the significance of these pervasive patterns is not entirely clear, connections between their structures and physical properties are fascinating to contemplate. Particular interest has been paid to a family of synthetically manufactured and commercially available dendritic polymers based on 2,2-bis(hydroxymethyl) propionic acid (bis-MPA) as a monomer. Composed of two hydroxyls and a carboxyl group, bis-MPA based structures hydrogen bond (H-bond) profusely. Given the high concentration and unique spatial orientation of end-groups, as well as the multitude of carbonyl, ester, and ether interior H-bond acceptors, a set of distinct H-bond organizations may be observed …

Asymmetric Synthesis Of Cα-Methyl-Γ- And Δ-Amino Acids From A Common Synthon And Evaluation Of Thionyl Chloride Assisted Peptide Esterifications, Emily Rose Vogel

Dissertations

C^α-methyl-γ- and δ-unnatural amino acids (UAAs) are important class of biomolecules used extensively as structural scaffolds, peptidomimetics, and in the development of pharmaceuticals. Due to steric congestion surrounding the quaternary center, asymmetric preparation of α,α-disubstituted UAAs are synthetically challenging. Herein, two methods for the synthesis of chiral synthons to prepare C^α-methyl-γ- and -δ-UAAs are reported. A crucial step in both strategies includes an enzymatic hydrolysis of prochiral malonic esters with pig liver esterase (PLE). The first method utilizes the Meyer Schuster rearrangement to prepare α,β-unsaturated diesters synthons, but the preparation of the precursor propargyl alcohol decomposes …

Development Of The Regenerative Glycosylation Approach For Manual And Automated Oligosaccharide Synthesis, Swati Sudhir Nigudkar

Dissertations

It has been recognized that carbohydrates are involved in all phases of life beginning with the embryonic development and cell growth. However, it is the involvement of carbohydrates in the progression of various deadly diseases that gave these natural compounds significant roles in diagnostics and as pharmaceuticals. Although carbohydrates are highly desirable to the biological and medical communities, these molecules are still very challenging targets for chemists. Functionalization, derivatization, controlling anomeric stereoselectivity, purification, and characterization are all existing experimental hurdles towards producing synthetic carbohydrates in large quantities and high purity. Advances in chemistry and biochemistry have certainly facilitated the synthesis …

Mining Biological Networks Towards Protein Complex Detection And Gene-Disease Association, Eileen Marie Hanna

Dissertations

Large amounts of biological data are continuously generated nowadays, thanks to the advancements of high-throughput experimental techniques. Mining valuable knowledge from such data still motivates the design of suitable computational methods, to complement the experimental work which is often bound by considerable time and cost requirements. Protein complexes or groups of interacting proteins, are key players in most cellular events. The identification of complexes not only allows to better understand normal biological processes but also to uncover Disease-triggering malfunctions. Ultimately, findings in this research branch can highly enhance the design of effective medical treatments. The aim of this research is …

Methods For The Direct Simulation Of Nanoscale Film Breakup And Contact Angles, Kyle Mahady

Dissertations

This thesis investigates direct simulation of fluids with free surfaces and contact lines, with a focus on capturing nanoscale physics in a continuum based computational framework. Free surfaces and contact lines have long presented some of the most challenging problems in computational fluid dynamics. Extensive progress has been made in recent years, and a wide variety of different methods are currently employed for direct simulation in these contexts. The complexity of the full governing equations for such flows poses significant challenges in terms of analytical techniques, and leads to lengthy computational times for direct simulations. For these reasons, reduced models …

Thermochemistry And Kinetics: Hydrogen Atom Addition Reactions With Alkenes, Oxidation Of Cyclopentadienone, Trifluoroethene And Transport Properties, Suriyakit Yommee

Dissertations

Thermochemical and transport properties and reaction kinetic parameters are important to understand and to model atmospheric chemistry, combustion and other thermal systems. These processes are all important to the environment. Thermochemical properties kinetic parameters and models for several atmospheric and combustion related chemical systems are determined using computational chemistry coupled with fundamentals of thermodynamics and statistical mechanics. Transport properties of hydrocarbon and oxygenated hydrocarbons which are important to the calculation of fluid dynamics of gas phase flow reactions and mixing needed for evaluation in the combustion and thermal (flow) fluid dynamic modeling. Transport properties of radicals cannot be measured so …

Social Analytics For Health Integration, Intelligence, And Monitoring, Xiang Ji

Dissertations

Nowadays, patient-generated social health data are abundant and Healthcare is changing from the authoritative provider-centric model to collaborative and patient-oriented care. The aim of this dissertation is to provide a Social Health Analytics framework to utilize social data to solve the interdisciplinary research challenges of Big Data Science and Health Informatics. Specific research issues and objectives are described below.

The first objective is semantic integration of heterogeneous health data sources, which can vary from structured to unstructured and include patient-generated social data as well as authoritative data. An information seeker has to spend time selecting information from many websites and …

Investigation Of Infinite-Dimensional Dynamical System Models Applicable To Granular Flows, Hao Wu

Dissertations

Recently Blackmore, Samulyak and Rosato developed a class of infinite-dimensional dynamical systems in the form of integro-partial differential equations, which have been called the BSR models. The BSR models were originally derived to model granular flows, but they actually have many additional applications in a variety of fields. BSR models have already been proven to be completely integrable infinite-dimensional Hamiltonian dynamical systems for perfectly elastic interactions in the case of one space dimension, but the well-posedness question of these systems is at least partially answered for the first time here. In particular, dynamical systems of the BSR type are proven …

Soluble Amyloid-Beta 42 Aggregates Stimulate Cellular Inflammation Independent Of Cd47, Sanjib Karki

Dissertations

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by the accumulation and deposition of aggregated amyloid-β protein (Aβ). Most of the studies indicate that Aβ1-42) and Aβ(1-40) play an important role in the neurodegenerative pathology in AD. A critical component of AD pathology is inflammation, which results from the activation of glial cells around the Aβ deposits. The goal of my dissertation research was to determine the role of Aβ aggregation in microglia-triggered inflammation and identify cellular components that mediate the inflammatory response. CD47 is a cellular receptor found on the microglia surface and it has been proposed to have …

Maintaining Consistency Between A Design Model And Its Implementation, Hector M. Chavez

Dissertations

Software design models are increasingly being used as part of the software development process as analysis and design artifacts and to automatically generate code that developers can further modify or extend, greatly expediting the software development process. This, however, has introduced the challenge of maintaining consistency between the design models and their implementation as they evolve during the development process. Traditional software testing and verification techniques have been well studied in the past, and they are an integral part of many software development projects, however, they are not well suited for consistency checking between a design model and its implementation. …

Ultrafast Charge Carrier Dynamics In Bare And Surface-Modified Semiconductor Nanoparticles, Jameel Abdul-Hadi Hasan

Dissertations

Charge-carrier relaxation dynamics in semiconductor nanoparticles has been in the forefront of research for last three decades both for their fundamental nature as well as for applications in light-harvesting, luminescent labels, light-emitting diodes and nonlinear optics. Significant research has focused on II-VI semiconductors with emphasis on CdS and CdSe that are toxic. On the other hand, ZnO and TiO2 semiconductor nanoparticles are less toxic and have enormous applications in photo-catalysis, water splitting, solar cells and optical sensors. However, the investigations of charge-carrier dynamics in these semiconductor nanomaterials compared to II-VI semiconductor quantum dots are quite limited. The knowledge of charge-carrier …

Solution Of Nonlinear Time-Dependent Pde Through Componentwise Approximation Of Matrix Functions, Alexandru Cibotarica

Dissertations

Exponential propagation iterative (EPI) methods provide an efficient approach to the solution of large stiff systems of ODE, compared to standard integrators. However, the bulk of the computational effort in these methods is due to products of matrix functions and vectors, which can become very costly at high resolution due to an increase in the number of Krylov projection steps needed to maintain accuracy. In this dissertation, it is proposed to modify EPI methods by using Krylov subspace spectral (KSS) methods, instead of standard Krylov projection methods, to compute products of matrix functions and vectors. This improvement allowed the benefits …

Assessing Biogeochemical Impacts And Environmental Conditions Associated With Cross-Shelf High Chlorophyll Plumes In The Northern Gulf Of Mexico, Erin Brooke Jones

Dissertations

The northern Gulf of Mexico is a complex marine system subject to episodic physical phenomena such as loop current eddies. Flow fields generated by these eddies can result in cross-shelf exchanges between riverine influenced shelf waters and the offshore water column. This study considers the impacts of high chlorophyll plumes (HCPs) resulting from cross-shelf exchanges to the bio-optical properties of affected waters and how these plumes are influenced by their environment. The seasonal, interannual and decadal chlorophyll cycles of the Gulf of Mexico and the northern Gulf of Mexico are described to provide context for evaluating the ecological effects of …

On The Selection Of A Good Shape Parameter For Rbf Approximation And Its Application For Solving Pdes, Lei-Hsin Kuo

Dissertations

Meshless methods utilizing Radial Basis Functions~(RBFs) are a numerical method that require no mesh connections within the computational domain. They are useful for solving numerous real-world engineering problems. Over the past decades, after the 1970s, several RBFs have been developed and successfully applied to recover unknown functions and to solve Partial Differential Equations (PDEs).
However, some RBFs, such as Multiquadratic (MQ), Gaussian (GA), and Matern functions, contain a free variable, the shape parameter, c. Because c exerts a strong influence on the accuracy of numerical solutions, much effort has been devoted to developing methods for determining shape parameters which provide …

Picolinyl-Assisted Approaches To Stereocontrolled Glycosylation, Jagodige Prithika Yasomanee

Dissertations

Although carbohydrates are the most abundant molecules on Earth, our current knowledge of these fascinating natural compounds is still limited. Some aspects that are already known include the carbohydrate involvement in damaging cellular processes such as bacterial and viral infections, development of tumors, metastasis, septic shock, etc. Consequently the development of effective methods for the synthesis, isolation, analysis, and investigation of complex carbohydrates has become critical in all areas of glycoscience. Among various focus areas, stereocontrolled glycosylation has emerged as a topic of particular importance. Yet, it remains a remarkable challenge to chemists because a new chirality center is formed …

Understanding Mechanistic Details Of Neuroinflammatory Pathways Stimulated By The Alzheimer's Disease Amyloid-Beta Protein, Shana Usery

Dissertations

Alzheimer’s disease (AD) is characterized by neuroinflammation. Senile plaques composed of aggregated amyloid-β protein (Aβ) are found in AD patients’ brains. The Aβ is formed by the proteolytic cleavage of the amyloid precursor protein (APP) resulting in Aβ fragments that are 39-42 amino acids in length. The two most common peptides are Aβ(1-40) and Aβ(1-42), which differ by two amino acids, isoleucine and alanine. Within the brain of AD patients, Aβ monomer self-assembles to form several aggregate morphologies, including oligomers, protofibrils, and fibrils. Activated microglial cells and associated secreted proinflammatory cytokines surround these plaques producing a localized inflammatory environment in …

Fast And Sensitive Genome-Hashing Software And Its Application In Using Ngs As A Detection Agent For Bacterial Presence In Oral Metagenomic Samples, Paul Michael Gontarz

Dissertations

Next generation sequencing has increased the throughput of sequenced DNA into the range of billions of nucleotides sequenced per day. With the increased speed of DNA sequencing and the short length of reads produced by next generation sequencers, a significant challenge has been created in quickly and accurately assembling the hundreds of millions of short reads created by modern sequencing instruments into their full genomic sequences. With the increase in throughput in next generation sequencing and the decrease in time and cost to perform DNA sequencing, novel applications for DNA sequencing are being considered. Among them is a methodology by …

Electron Transmission Through Micrometer Sized Funnelshaped Tapered Glass Capillaries And Electron Micro-Beam Production, Samanthi Jayamini Wickramarachchi

Dissertations

The prime motivation of this work is to understand the fundamental transmission process of an electron beam through a funnel-shaped capillary taking into account its shape together with the energy, angular and time dependence of the transmitted electrons produce a microsized electron beam. The utilized capillaries had inlet/outlet diameters of 800/16 μm, 800/100 μm and lengths of 35 mm. Considerable transmission of 800 and 1000 eV electrons for tilt angles up to 1.5^o and only small transmission for 500 eV electrons was observed for the capillary with the smaller outlet diameter of 16 μm. Incident electrons with energies of …

Edge Colorings Of Graphs And Their Applications, Daniel Johnston

Dissertations

Edge colorings have appeared in a variety of contexts in graph theory. In this work, we study problems occurring in three separate settings of edge colorings.

For more than a quarter century, edge colorings have been studied that induce vertex colorings in some manner. One research topic we investigate concerns edge colorings belonging to this class of problems. By a twin edge coloring of a graph G is meant a proper edge coloring of G whose colors come from the integers modulo k that induce a proper vertex coloring in which the color of a vertex is the sum of …