Physical Sciences and Mathematics Commons^™

Iron Uptake And Accumulation Is A Target Of Nickel Toxicity During The Lag Phase In Escherichia Coli, Geoffrey Tuttle Ford

Theses and Dissertations

Various transition metals are essential to all forms of life, and are only required in trace amounts. But this dependence comes as a double-edged sword. All organisms must maintain a careful intracellular quota that does not traverse outside an acceptable range. One transition metal in particular is nickel. The importance of this transition metal has been debated widely and its function varies greatly between organisms, including bacteria. However, the adverse effects caused by over exposure to this metal have been the center of much experimentation in recent years. Still, the mechanisms of nickel toxicity and the subsequent effects on cellular …

Structural And Functional Studies Of Nicotinamide Adenine Dinucleotide And Streptolysin S Biosynthesis Proteins From Streptococcus Pyogenes, William T. Booth

Theses and Dissertations

Invasive infections caused by Streptococcus pyogenes, also known as Group A Strep (GAS), results in approximately 600,000 deaths annually. With evidence of antibiotic-resistant strains of this bacterium on the rise, there is a need for the identification of new drug targets to control these infections. In our approach we target the quinolinate-salvage pathway (QSP) and the streptolysin S (SLS) biosynthesis pathway. The QSP provides a secondary pathway for NAD+ biosynthesis within this organism; the SLS pathway leads to the formation of a quorum sensing molecule (SLS). We hypothesize that inhibition of the pathways will lead to GAS cell death or …

Development And Application Of Bayesian Semiparametric Models For Dependent Data, Junshu Bao

Theses and Dissertations

Dependent data are very common in many research fields, such as medicine (repeated measures), finance (time series), traffic (clustered), etc. Effective control/modeling of the dependency among data can enhance the performance of the models and result in better prediction. In many cases, the correlation itself may be of great interest. In this dissertation, we develop novel Bayesian semi-/nonparametric regression models to analyze data with various dependence structures. In Chapter 2, a Bayesian non- parametric multivariate ordinal regression model is proposed to fit drinking behavior survey data from DWI offenders. The responses are two-dimensional ordinal data, drinking frequency and drinking quantity …

Behavior Of Rare Earth Elements And High-Field Strength Elements During Peridotite - Seawater Interaction, Carl Pasquale Frisby

Theses and Dissertations

Serpentinized abyssal peridotites are evidence for active communication between the Earth’s hydrosphere and the upper mantle, where exchange and retention of both major and trace elements occur. Rare earth elements (REE) and high-field strength elements (HFSE: Ti, Zr, Hf, Nb, Ta) are generally thought of as immobile during serpentinization. In partially serpentinized abyssal peridotites, clinopyroxenes typically retain radiogenic Nd and Hf isotopic signatures that have been used to infer the composition and high temperature processes in the upper mantle. However, bulk rock Nd isotopes in some serpentinized abyssal peridotites less radiogenic values that approach that of seawater, which has been …

Determination Of The Polarization Observables Cx, Cz, And Py For Final-State Interactions In The Reaction −!D ! K+−!N, Tongtong Cao

Theses and Dissertations

The hyperon-nucleon (YN) interaction plays a key role in hypernuclei and strange nuclear matter and is an important part of the baryon-baryon interaction. While considerable progress has been made in the understanding of the nucleon-nucleon (NN) interaction, the YN interaction is less known. Some parameters of the YN potential can be obtained from the NN potential by using SU(3) symmetry. However, due to broken SU(3) there are parameters, which must be obtained from fits to experimental data. High-statistics data on exclusive photoproduction off the deuteron initiated with highly-polarized photons offer a unique opportunity to extract a large sample of polarization …

Bayesian Nonparametric Approaches To Multiple Testing, Density Estimation, And Supervised Learning, William Cipolli Iii

Theses and Dissertations

This dissertation presents methods for several applications of Polya tree models. These novel nonparametric approaches to the problems of multiple testing, density estimation and supervised learning provide an alternative to other parametric and nonparametric models. In Chapter 2, the proposed approximate finite Polya tree multiple testing procedure is very successful in correctly classifying the observations with non-zero mean in a computationally efficient manner; this holds even when the non-zero means are simulated from a mean-zero distribution. Further, the model is capable of this for “interestingly different” observations in the cases where that is of interest. Chapter 3 proposes discrete, and …

From Near And Far: Utilization Of In-Situ And Remotely Sensed Satellite Data From Nasa And Noaa, Jessica Rochelle Price Sutton

Theses and Dissertations

Satellite remote sensing observations have been used for numerous studies to better understand physical and biological properties over varying spatial and temporal scales. Depending on the satellite and sensor, the satellite-derived observations can provide high spatial and temporal resolution for many important physical and biological variables. While there are many limitations in utilizing satellite remote sensing products, there are also many advantages. This dissertation investigates three different applications for satellite remote sensing products to address climatological and ecological concerns. This dissertation is motivated by two overall research questions: (1) How can satellite remote sensing products be used to address important …

North American Butterfly Association Counts At Congaree National Park: A Case Study For Connecting Citizen Science To Management, Austin Clarridge

Theses and Dissertations

Citizen science is becoming an ever more popular way for scientists and resource managers to deal with needs for large temporal and spatial scale datasets. It provides a free or low cost means for collection of extensive amounts of data across time and space while acting as a public education and outreach tool, empowering communities to be involved in the management decisions being made in their back yard. Though large, well-known citizen science programs such as the Christmas Bird Counts are being used extensively for peer reviewed literature and management decisions, there are numerous smaller, local counts that have the …

Sensitivity Of The Cuore Detector To Solar Axions, Dawei Li

Theses and Dissertations

The strong CP problem in Quantum Chromodynamics (QCD), predicts the neutron electric dipole moment to be a factor of 1010 larger than the observed upper bound [15]. Roberto Peccei and Helen Quinn [58, 63] proposed an elegant solution to this problem by introducing a global U(1)PQ symmetry that is spontaneously broken at an energy scale fa. A consequence of this symmetry-breaking is that a new spin-zero neutral pseudoscalar particle, the axion, is generated which is a Nambu-Goldstone boson [70, 78]. The “invisible axion” models with fa >> fEW, typically KSVZ and DFSZ models, have been proposed and recognized to be far-reaching …

Ligand-Induced Magnetic Changes In Metal Thin Films, Fiona Senta Oberbeck-Oxsher

Theses and Dissertations

The investigation of magnetic properties of thin films whose surfaces were modified by organic molecules shows that the addition of any functional group to the surface measurably changes the magnetic properties. The effect often scales with ligand strength and is not limited to surfaces with ferromagnetic properties. Improving upon the technique developed by Knaus et al. [1], a stable and sensitive device was developed to measure this magnetic effect using the planar Hall effect (PHE) in order to shed light onto controversial questions of purported paramagnetism of thiolated gold. There is a measureable non-diamagnetic response of thin gold layers when …

Platinum Decoupling From Pge In Peridotitic Sulfides From The St. Elena Ophiolite In Costa Rica, Jessica A. Holm

Theses and Dissertations

The platinum group elements (Os, Ir, Ru, Rh, Pt, Pd) are important petrogenetic tracers of mantle processes and the Re-Os isotope system an important tool for tracing ancient depletion and refertilization processes in the mantle. A key characteristic of these elements is that they are siderophile and chalcophile, and their abundance in the Earth’s mantle is thought to be controlled by sulfides. Existing thermodynamic data suggests that at reducing conditions similar to those found at the early stages of serpentinization, PGE may exist as alloys in the mantle. While numerous studies report on the bulk peridotite PGE and sulfide PGE …

Quantum Dot Metrics For Preparative Chemistry And Fluorescence Applications, Yi Shen

Theses and Dissertations

Colloidal semiconductor quantum dots (QDs) are considered to be a promising candidate for bio-imaging and solar cells because of their extraordinary photo-physical properties. The ultimate goal of this dissertation is to design a reliable matrix and a reproducible method to prepare QDs-based biocompatible probe for fluorescence applications. Synthesis of quantum dots requires a large amount of ligands to improve the stability at high temperature. However, for further application and surface modification of QDs, excess ligands must be removed. In this dissertation, I will first describe using gel permeation chromatography (GPC) as a media to purify different types of QDs. A …

Small Mud And Sand Filled Paleochannels Offshore Charleston, Sc, Erin Smoak

Theses and Dissertations

The spatial variations of Quaternary sediments on the continental shelf record the progression of depositional environments during the latest sea-level rise, and are fundamental controls on submarine groundwater discharge (SGD) flow. SGD on continental shelves is an important but poorly constrained process. Spatial variations of lithologies on continental shelves, such as sand-filled paleochannels, are assumed to play a fundamental role in controlling where SGD occurs but coincident seismic mapping and sedimentological data are rare. Here we combine seismic mapping of paleochannel locations with sediment cores to examine the sedimentary characteristics of paleochannel fill and interfluvial deposits. To establish paleochannel locations …

Temperature Dependent Transport Properties Of Chemical Vapor Deposition Graphene With Metal And Metal Hydride Surface Functionalization, Bochen Zhong

Theses and Dissertations

Graphene, a two-dimensional semi-conductor material containing carbon atoms tightly bonded together in a hexagonal structure, was first isolated by mechanical exfoliation in 2004. Over the past decade, it has drawn huge research interest due to its outstanding mechanical, thermal, and electrical properties. These unique properties of graphene lead to very high carrier mobility. In particular, after an annealing treatment to remove the residual impurities, the suspended graphene mobility exceeds 200,000 cm2/Vs. However, this value is highly reduced to only a few thousand cm2 /Vs in supported graphene on SiO2 or SiC substrates, due to different sources of scattering. For example, …

Ecohydrology And Groundwater Dynamics In A Salt Marsh Island, Andrea L. H. Hughes

Theses and Dissertations

Tidal salt marshes are extraordinarily productive and valuable ecosystems that provide via groundwater a not insignificant portion of coastal solute and nutrient budgets. Among the many goods and services they provide are habitat for diverse wildlife, protection for coastal communities during storms, and protection for coastal surface waters by filtering anthropogenic pollutants. One threat to the health of tidal salt marshes along the East Coast have been episodes of Acute Marsh Dieback (AMD) from 1999 to 2001. Dieback was observed at North Inlet salt marsh from 2000 to 2001. Since salt marsh hydrology is dominated by the local tidal regime, …

Satellite-Assisted Assessment Of The Effects Of Human Development On Coral Reefs, Roatan Honduras, Clayton A. Helm

Theses and Dissertations

Human intervention is degrading coastal marine environments on a global scale. Coral reefs are one of the most valuable ecosystems occupying coastal areas that provide a vast majority of consumable fish, recreational activities, and protection from extreme events, such as tropical cyclones. Unfortunately, as human development activities such as the construction of buildings, road infrastructure, and agriculture increase in coastal areas, so do the detrimental impacts on the health of coral reefs. Consequences of coastal development such as pollution, sedimentation, eutrophication, overfishing, and recreational activities have been linked to diminished coral health. A degraded coral ecosystem can often be identified …

The Development Of A High Resolution Deep-Uv Spatial Heterodyne Raman Spectrometer, Nirmal Lamsal

Theses and Dissertations

Raman spectroscopy is a light scattering technique that has a huge potential for standoff measurements in applications such as planetary exploration because a Raman spectrum provides a unique molecular fingerprint that can be used for unambiguous identification of target molecules. For this reason, NASA has selected a Raman spectrometer as one of the major instruments for its new Mars lander mission, Mars 2020, in the search for biomarkers that would be the indicators of past or present life. Raman scattering is strongest at UV wavelengths because of the inherent increase in the Raman cross section at shorter wavelengths and because …

A Comparison Of Framing In Two Environmental Conflicts, Alexander M. Iannone

Theses and Dissertations

Frames can be perspectives about people, objects, events, or settings that guide action based on past experiences and values. Conflicts are created by different stakeholders “holding conflicting frames.” Researchers in the past have used framing analysis to try and better understand environmental conflicts that tend to perpetuate for extended periods of time. A set of researchers have relied on specific framing categories and typologies as a framework for analysis. They have found that the strong presence or lack thereof certain frames can tell us a lot about conflict dynamics and shed light into the undercurrents driving the complexity of the …

An Integrated Structural Analysis On Seismic Of A Paleo Mound Development (Woolsey Mound, Northern Gulf Of Mexico), Ricardo Tomas Troco Kabila

Theses and Dissertations

Woolsey Mound is ~1 km diameter thermogenic gas hydrate and cold seep (GHCS) complex system. It is located at ~900 m water depth in the Mississippi Canyon Lease Block 118 (MC–118) on the upper continental slope of the northern Gulf of Mexico (GOM). Due to its complex geology, widespread hydrate seepage activity and presence of benthic habitat, the mound serves as a permanent research site for a multidisciplinary seafloor observatory, thus providing insights into the dynamics of shallow fluid expulsion, their spatial and time variations and possible geological forcing mechanisms.

This study utilizes a set of high resolution 2D autonomous …

Novel Methods For Analyzing Longitudinal Data With Measurement Error In The Time Variable, Caroline Munindi Mulatya

Theses and Dissertations

In some longitudinal studies, the observed time points are often confounded with measurement error due to the sampling conditions, resulting into data with measurement error in the time variable. This type of data occurs mainly in observational studies when the onset of a longitudinal process is unknown or in clinical trials when individual visits do not take place as specified by the study protocol, but are often rounded to coincide with the study protocol. Methodological and inferential implications of error in time varying covariates for both linear and nonlinear models have been studied widely. In this dissertation, we shift attention …

Alongshore Momentum Balance Over Shoreface-Connected Ridges, Fire Island, Ny, Conor Ofsthun

Theses and Dissertations

Bathymetric variations, such as shoreface-connected ridges (SFCRs), modify inner shelf circulation, altering the significance of and relationships between alongshore momentum balance terms. The inner shelf of Fire Island, NY provides a study site representative of SFCRs around the world. During the winter of 2014, hydrodynamic observations (~12 m depth) from 6 ADCPs, 3 SeaGauge pressure sensors, 2 tide gauges, and 2 meteorological buoys were collected over a region of the inner shelf spanning a full wavelength of one such SFCR. Analysis of the data, under westward wind forcing, revealed a predominantly alongshore circulation with localized offshore (onshore) current veering over …

Spatio-Temporal Analysis Of The Occupational Fatal Victimization Of Law Enforcement Officers In The Us, Xueyi Xing

Theses and Dissertations

The models with constant coefficients of the covariates across space and time are commonly used in spatio-temporal analyses. However, the associations between risk factors and the outcome could have locally differential temporal trends in many cases. In this study, a Bayesian latent cluster modeling strategy is employed to identify potential spatial clusters in which locally specific sets of temporally varying coefficients of covariates are allowed. A state-level panel data of police officers occupational fatal victimization for the years 1979-2010 is used. To accommodate overdisperson and excess zeros, a negative binomial model and zero-inflated Poisson/negative binomial models are also utilized. A …

Characterization Of 1-Deoxy-D-Xylulose 5-Phosphate Reductoisomerase (Dxr) From Vibrio Vulnificus, Nikita K. Ussin

Theses and Dissertations

Vibrio vulnificus, a gram-negative bacterium, is the leading cause of seafood-borne illnesses and mortality in the United States. Previous studies of bacterial pathogens have identified a metabolite essential to V. vulnificus growth and function. 1-deoxy-D-xylulose 5-phosphate reductoisomerase (Dxr) is an essential enzyme in the viability of many bacteria and catalyzes the rearrangement of 1-deoxy-D-xylulose 5-phosphate (Dxp) to 2-C-methylerythritol 4-phosphate (MEP) within the MEP pathway found in plants and bacteria. Previous studies have been conducted to characterize Dxr homologs from other pathogens including E. coli, M. tuberculosis, and P. falciparum. Information on the structural and enzymatic characteristics of Dxr from Vibrio …

On Crown-Free Set Families, Diffusion State Difference, And Non-Uniform Hypergraphs, Edward Lawrence Boehnlein

Theses and Dissertations

We present results in three different arenas of discrete mathematics. Let La(n, H) denote the cardinality of the largest family on the Boolean lattice that does not contain H as a subposet. Denote π(H) := limn→∞ La(n,H) (bn/ n2c) . A crown O2k for k ≥ 2 is a poset on 2 levels whose Hasse diagram is a cycle. Griggs and Lu (2009) showed π(O4k) = 1 for k ≥ 2. Lu (2014) proved π(O2k) = 1 for odd k ≥ 7. We prove that the maximum size of a O6 -free family, when restricted to the middle two levels …

Score Test Derivations And Implementations For Bivariate Probability Mass And Density Functions With An Application To Copula Functions, Roy Bower

Theses and Dissertations

This dissertation is comprised and grounded in statistical theory with an application to solving real world problems. In particular, the development and implementation of multiple score tests under a variety of scenarios are derived, applied, and interpreted. In chapter 2, I propose a score test for independence of the marginals based on Lakshminarayana’s bivariate Poisson distribution. Each marginal distribution of the bivariate model is a univariate Poisson distribution, and the parameters of the bivariate distribution can be estimated using maximum likelihood methods. The simulation study shows that the score test maintains size close to the nominal level. To assess the …

The Development Of A Miniature Spatial Heterodyne Raman Spectrometer For Applications In Planetary Exploration And Other Extreme Environments, Patrick Doyle Barnett

Theses and Dissertations

Space exploration is arguably one of the most important endeavors our species has ever undertaken. Rapid advances in rocketry and robotics in recent years has allowed for positioning of complex scientific instruments on other planets with a precision that was previously thought impossible. This, along with the need for more sophisticated chemical measurements to achieve the goals of new, more ambitious missions and recent advances in in-situ and remote spectroscopic techniques, has led to a boom in the use of spectroscopic instruments for space exploration. However, future missions to the moons of Jupiter and Saturn, along with other planetary bodies …

Utilization Of Satellite-Derived Salinity For Enso Studies And Climate Indices, Caroline Mary Corbett

Theses and Dissertations

Conventionally, El Niño-Southern Oscillation (ENSO) is studied using sea surface temperature (SST) observations in the central and eastern equatorial Pacific Ocean. Recently, sea surface salinity (SSS) in the equatorial Pacific has been studied in relation to the phases of ENSO. Previously, SSS was observed in the equatorial Pacific using the Tropical Ocean Global Atmosphere (TOGA) / Tropical Atmosphere Ocean (TOA), the Argo float network, and Oceanic General Circulation Models (OGCM). The launch of NASA’s Aquarius Salinity Mission and ESA’s Soil Moisture Ocean Salinity (SMOS) opened a new era in which high resolution global near real-time SSS observations are readily available. …

Using Synthetic Lectins To Investigate Metastatic Potential In Colon Cancer, Erin E. Gatrone

Theses and Dissertations

Cancer is a disease that affects millions of people each year and it is well established that early diagnosis is a key factor towards improving survival rate, with that in mind there is a great need for better diagnostics. From the earliest onset of cancer, changes can be detected in the type and amount of carbohydrates expressed by the cancer cells, i.e., aberrant glycosylation. This process results in differing glycosylation patterns that can be used to detect cancer. Aberrant glycosylation can also greatly affect the potential of cancer cells to metastasize and can be used to stage the disease as …

Semiparametric Estimation Methods For Complex Accelerated Failure Time Model, Yinding Wang

Theses and Dissertations

The proportional hazards (PH) model and the accelerated failure time (AFT) model are the two most popular survival models in fitting the right-censored data. The AFT model is a useful alternative to the PH model, particularly when the PH assumption is not satisfied. Usually, the linear association is assumed with logarithm of survival time in the AFT model. However, the nonlinear association may exist in practice. The first project aims to handle the nonlinear component in the AFT model, which is called the semiparametric additive partial accelerated failure time (AP-AFT) model. Two estimation methods based on the rank-smooth method and …

Learning Human Poses From Monocular Images, Xiaochuan Fan

Theses and Dissertations

In this research, we mainly focus on the problem of estimating the 2D human pose from a monocular image and reconstructing the 3D human pose based on the 2D human pose. Here a 3D pose is the locations of the human joints in the 3D space and a 2D pose is the projection of a 3D pose on an image. Unlike many previous works that explicitly use hand-crafted physiological models, both our 2D pose estimation and 3D pose reconstruction approaches implicitly learn the structure of human body from human pose data.

This 3D pose reconstruction is an ill-posed problem without …