Physical Sciences and Mathematics Commons^™

Survival Analysis - Breast Cancer, Minh Hoang Pham

Undergraduate Journal of Mathematical Modeling: One + Two

In this study we used the parametric survival approach to analyze the survival time of African American breast cancer patients. In research about the survival time of patients, the Cox Proportional Hazard model, a semi-parametric method, is primarily used, but this approach does not rely on the distributional assumptions. The parametric method is more consistent with a theoretical approach compared to a semi-parametric approach. We observe that the survival time of African American breast cancer patients follows the Weibull Probability Distribution. First, we fitted the model to represent the survival ability of the general population (African American women diagnosed with …

Low Resolution Examination Of Cool-Water Carbonate Foraminifera Around Tasmania During The Pleistocene, Sara Jane Hughes

Masters Theses

Benthic foraminifera from nine sediment samples recovered during Ocean Drilling Program (ODP) Leg 189: The Tasman Gateway were examined to determine how changing Southern Ocean conditions affect benthic foraminiferal populations. All samples come from Site 1168 situated 70km from the coast of Tasmania on the western continental slope (2463 m below the surface) and are spaced at roughly 150,000 years apart. Identifications of benthic foraminifera were done with a dissecting microscope and several reference books. Foraminifera were correlated with environmental proxy data obtained from Brughmans (2003) (total organic carbon, carbonate, siliciclastics, coarse fractions, chlorin, barium, aluminum, iron, and titanium) and …

Role Of Feedstock And Process Conditions On Biomass Gasification For Synthesis Gas Production, Mayoorey Murugathasan

Masters Theses

In this study gasification of three different biomasses were performed to study the impact of process conditions and different feed stocks on final syngas composition. Final composition of the syngas determines the energy value of the resulting syngas and the suitability of syngas in chemical synthesis applications. Three kinds of feedstocks studied include switch grass pellets:wood chips 50:50 mixture, wood pellets:wood chips 50:50 mixture and wood pellets.

The effect of process conditions including temperature and feed stock composition on syngas composition were studied. Gas chromatography was used to analyze the final gas composition of syngas samples collected at five different …

Theoretical And Spectroscopic Analysis Of Ch...Π Interactions Of Fluorinated Aromatic Systems, Anuradha Gayathri Akmeemana

Masters Theses

CH...π interactions are non-covalent interactions which occur in organic compounds that are important in biological and chemical sciences in many ways. Microwave spectroscopy is an important technique that can be used to detect CH...π interactions in the gas phase molecules. Previously microwave spectroscopic studies of complexes containing CH...π interactions, benzene...HCCH (Ulrich, N.W.; Seifert, N.A.; Dorris, R.E.; Peebles, R.A.; Pate, B.H.; Peebles, S.A., Phys. Chem. Chem. Phys. 2014, 16, 8886-8894) and fluorobenzene...HCCH (Ulrich, N.W.; Songer, T.S.; Peebles, R.A.; Peebles, S.A.; Seifert, N.A.; Perez, C.; Pate, B.H. Phys. Chem. Chem. Phys., 2013, 15, 18148-18154) were done at Eastern Illinois University and the …

Computational And Experimental Studies Of Non-Covalent Interactions: Characterization Of Ch...Π Interactions And Structure Of 1,1-Difluoroethylene...Carbon Dioxide, Ashley M. Anderton

Masters Theses

Weakly bound CH/π interactions, due to the abundance of C-H bonds and π systems that exist in larger organic molecules, are an important driving force in the construction of biomacromolecules, supramolecular assemblies and crystal packing of organic compounds. To assist in the characterization of CH/π interactions, a density functional theory (DFT) study has been conducted to determine a quick and cheap method for accurate determination of the binding energy and rotational constants for CH/π interactions. Seven complexes were used in this study: five benzene-HY complexes (where Y= C≡CH, Cl, F, Br and C≡N) and two fluorobenzene-HY complexes (where Y= C≡CH …

Synthesis And Characterization Of Molecular Components For The Preparation Of Poly-Rotaxanes, Austin P. Welti

Masters Theses

The self-sorting ability of certain crown ethers make them important players in the field of supramolecular chemistry, especially those studying mechanically interlocked molecules (MIMs). Of these MIMs, rotaxanes and catenanes are the most common. Our approach in the synthesis of poly-rotaxane systems involves the preparation of axles containing multiple recognition motifs to determine the self-sorting principles that each motif shows. These principles include narcissistic self-sorting, and also type I and type II social self-sorting principles. Using these techniques, poly-rotaxane formation can be made readily available.

A hetero-poly-rotaxane equipped with a naphthalene diimide (NDI) site and two ammonium salt sites has …

Plan B Career Information: Annotated Resource List, Elizabeth Howard

Undergraduate Research Award

No abstract provided.

An Empirical Analysis Of Cost Recovery In Superfund Cases: Implications For Brownfields And Joint And Several Liability, Howard F. Chang, Hilary Sigman

All Faculty Scholarship

Economic theory developed in the prior literature indicates that under the joint and several liability imposed by the federal Superfund statute, the government should recover more of its costs of cleaning up contaminated sites than it would under nonjoint liability, and the amount recovered should increase with the number of defendants and with the independence among defendants in trial outcomes. We test these predictions empirically using data on outcomes in federal Superfund cases. Theory also suggests that this increase in the amount recovered may discourage the sale and redevelopment of potentially contaminated sites (or “brownfields”). We find the increase to …

Laser Spectroscopy Of Radicals Containing Group Iiia And Va Elements, Robert A. Grimminger

Theses and Dissertations--Chemistry

Radicals are interesting to study because of importance in so many processes such as semiconductor growth or stellar evolution. Laser induced fluorescence (LIF) and wavelength resolved emission spectra of jet cooled HPS, HAsO, AsD₂, H₂PS, and F₂BO have been measured using the pulsed discharge jet technique.

Several bands in the à ¹A′′ − X̃ ¹A′ transition of HPS were observed and assigned with the help of ab initio calculations. The ab initio geometries showed that HPS does not follow Walsh’s predictions for the angle change upon electronic excitation; Walsh predicts an increase …

Temperature-Dependent Tunable Photoluminescence Properties Of Carbon Nanodots Derived From Polyethylene Glycol, Sin Hea Yeom

Theses and Dissertations--Chemistry

Fluorescent carbon dots (C-dots) are well known for their low cell-cytotoxicity, biocompatibility, low preparation cost, excitation dependent photoluminescence, and excellent photostability. Typically, raw C-dots have low quantum efficiency and thus researchers have been utilizing biocompatible polymers such as polyethylene glycol (PEG) as a passivation agent in order to increase fluorescence signal. In this work, we report fluorescent self-passivated carbon nanodots (CNDs) synthesized from PEG by using it as a carbon source as well as a passivating agent. Importantly, the addition of graphene quantum dots (GQDs) during the synthesis of self-passivated CNDs can tune photoluminescence property. The results of bioimaging and …

A Study Of Lignin Depolymerization By Selective Cleavage Of The Cα-Cβ Linkages In Lignin Model Compounds Via Baeyer-Villiger Oxidation & An Investigation Of The Channeling Reaction In Nitrogen-Doped Multiwalled Carbon Nanotubes (N-Mwcnts), Nikhil Dilip Patil

Theses and Dissertations--Chemistry

A STUDY OF LIGNIN DEPOLYMERIZATION BY SELECTIVE CLEAVAGE OF THE Cα-Cβ LINKAGES IN LIGNIN MODEL COMPOUNDS VIA BAEYER-VILLIGER OXIDATION

Lignin is amorphous aromatic polymer derived from plants and is a potential source of fuels and bulk chemicals. Herein, we present a survey of reagents for selective stepwise oxidation of lignin model compounds. Specifically, we have targeted the oxidative cleavage of Cα-Cβ bonds as a means to depolymerize lignin and obtain useful aromatic compounds. In this work, we prepared several lignin model compounds that possess structures, characteristic reactivity, and linkages closely related to the parent lignin polymer. We observed that selective …

Associating Severe Thunderstorm Warnings With Demographic And Landscape Variables: A Geographically Weighted Regression-Based Mapping Of Forecast Bias, Megan L. White

Theses and Dissertations--Geography

Severe thunderstorm warnings (SVTs) are released by meteorologists in the local forecast offices of the National Weather Service (NWS). These warnings are issued with the intent of alerting areas in the path of severe thunderstorms that human and property risk are elevated, and that appropriate precautionary measures should be taken. However, studies have shown that the spatial distribution of severe storm warnings demonstrates bias. Greater numbers of severe thunderstorm warnings sometimes are issued where population is denser. By contrast, less populated areas may be underwarned. To investigate the spatial patterns of these biases for the central and southeastern United States, …

Biomechanical Effects Of Trees And Soil Thickness In The Cumberland Plateau, Michael Shouse

Theses and Dissertations--Geography

Previous research in the Ouachita Mountains, Arkansas suggests that, on relatively thin soils overlying bedrock, individual trees locally thicken the regolith by root penetration into bedrock. However, that work was conducted mainly in areas of strongly dipping and contorted rock, where joints and bedding planes susceptible to root penetration are more common and accessible. This project extended this concept to the Cumberland Plateau, Kentucky, with flat, level-bedded sedimentary rocks. Spatial variability of soil thickness was quantified at three nested spatial scales, and statistical relationships with other potential influences of thickness were examined. In addition, soil depth beneath trees was compared …

Long-Term Change In Copepod Community Structure In The Western Antarctic Peninsula: Linkage To Climate And Implications For Carbon Cycling, Miram Rayzel Gleiber

Dissertations, Theses, and Masters Projects

Copepods are the dominant mesozooplankton in the Southern Ocean, but long- term change in their abundance and distribution along the Western Antarctic Peninsula (WAP), a region experiencing rapid climate warming, is unknown. Copepods are also potentially important grazers of phytoplankton in the WAP and contributors to carbon export through production of sinking fecal pellets. I examined summer (January- February) copepod community structure and abundance along the WAP over two decades (1993-2013) and investigated long-term trends in copepod abundance and their relationship with environmental parameters (sea ice, phytoplankton biomass and productivity, climate indices, and sea surface temperature). Copepods comprised on average …

Magneto-Optics And Magneto-Transport Studies On Thin Films For Sensor Applications, Kaida Yang

Dissertations, Theses, and Masters Projects

Recent progress and interest have bought considerable effort to bear on the synthesis and opportunities of magnetic thin films in different fields. There are applications in many fields, including remote sensing, waveguide applications, hard drive applications, etc. at the College of William and Mary, we have focused on utilizing magnetic thin films in some of these applications and are deeply involved in the optimization process of the thin films.

Fishes In Seagrass Habitats: Species Composition, Trophic Interactions, And Production, Kathryn L. Sobocinski

Dissertations, Theses, and Masters Projects

The value of habitats in terms of biological production is of interest to ecologists and resource managers. Seagrasses are a commonly occurring habitat type in shallow marine waters and have been shown to support high abundances of fish and invertebrates. In lower Chesapeake Bay, seagrasses grow in a shallow fringe in the subtidal zone. Although, ample evidence exists for the value of these habitats as foraging and rearing areas for a variety of organisms, the connectivity among species and the benefits derived from these habitats in terms of production have not been well described, especially for small, seasonally occurring finfishes. …

Studies Of Mortality Estimation, Amy Y. Then

Dissertations, Theses, and Masters Projects

Instantaneous total mortality rate Z can be partitioned into two components: fishing, F, and natural mortality, M. A number of data-poor methods have been developed to estimate Z, F, and M, and these methods tend to rely on fairly restrictive assumptions as well as on data types that are easy to obtain, e.g., length or other life history information. The overarching goal of this dissertation is to contribute to the advancement of methods for estimating these important and influential stock parameters. The relevant issues and the gaps in knowledge pertaining to these data-poor methods are outlined in the Introduction chapter …

Observation Of Turbulent Intermittency Scaling With Magnetic Helicity In An Mhd Plasma Wind Tunnel, David A. Schaffner, A. Wan, M. R. Brown

Physics Faculty Research and Scholarship

The intermittency in turbulent magnetic field fluctuations has been observed to scale with the amount of magnetic helicity injected into a laboratory plasma. An unstable spheromak injected into the MHD wind tunnel of the Swarthmore Spheromak Experiment displays turbulent magnetic and plasma fluctuations as it relaxes into a Taylor state. The level of intermittency of this turbulence is determined by finding the flatness of the probability distribution function of increments for magnetic pickup coil fluctuations B_ðtÞ. The intermittency increases with the injected helicity, but spectral indices are unaffected by this variation. While evidence is provided which supports the hypothesis that …

Solid State 1 H Spin - Lattice Relaxation And Isolated - Molecule And Cluster Electronic Structure Calculations In Organic Molecular Solids: The Relationship Between Structure And Methyl Group And T - Butyl Group Rotation, Xianlong Wang, Frank B. Mallory, Clelia W. Mallory, Hosanna R. Odhner, Peter A. Beckmann

Physics Faculty Research and Scholarship

We report ab initio density functional theory electronic structure calculations of rotational barriers for t-butyl groups and their constituent methyl groups both in the isolated molecules and in central molecules in clusters built from the X-ray structure in four t-butyl aromatic compounds. The X-ray structures have been reported previously. We also report and interpret the temperature dependence of the solid state 1H nuclear magnetic resonance spin-lattice relaxation rate at 8.50, 22.5, and 53.0 MHz in one of the four compounds. Such experiments for the other three have been reported previously. We compare the computed barriers for methyl group and t-butyl …

I-127 And Pb-207 Solid-State Nmr Spectroscopy And Nuclear Spin Relaxation In Lead Iodide: A Preliminary Study, R. E. Taylor, Peter A. Beckmann, Shi Bai, C. Dybowski

Physics Faculty Research and Scholarship

Lead iodide is a layered structure that experiences polytypism. The 2H polytype contains high rates of iodine vacancies but retains its stoichiometry. This characteristic feature makes it potentially useful for many practical applications. The hopping of iodine ions among vacancies is the dominant motion in the 2H polytype. We present a preliminary 127I and 207Pb solid-state nuclear magnetic resonance (NMR) spectroscopy and spin–lattice relaxation study of the 2H polytype below 400 K. We present reasonable models for the solid-state NMR results in terms of the effects of iodine hopping and lattice vibrations.

Fusarium Head Blight Resistance And Agronomic Performance In Soft Red Winter Wheat Populations, Daniela Sarti Dvorjak

Theses and Dissertations--Plant and Soil Sciences

Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe [telomorph: Gibberella zeae Schwein.(Petch)], is recognized as one of the most destructive diseases of wheat (Triticum aestivum L. and T. durum L.) and barley (Hordeum vulgare L.) worldwide. Breeding for FHB resistance must be accompanied by selection for desirable agronomic traits. Donor parents with two FHB resistance quantitative trait loci (QTL) Fhb1 (chromosome 3BS) and QFhs.nau-2DL (chromosome 2DL) were crossed to four adapted SRW wheat lines to generate backcross and forward cross progeny. F₂ individuals were genotyped and assigned to 4 different groups according to presence/ absence of …

Field-Scale Water And Solute Transport, Yang Yang

Theses and Dissertations--Plant and Soil Sciences

Spatial variability of soil properties complicates the understanding of water and solute transport at the field scale. This study evaluated the impact of land use, soil surface roughness, and rainfall characteristics on water transport and Br^- leaching under field conditions by means of a new experimental design employing scale-dependent treatment distribution. On a transect with two land use systems, i.e., cropland and grassland, rainfall intensity and the time delay between Br^- application and subsequent rainfall were arranged in a periodically repetitive pattern at two different scales. Both scales were distinct from the scale of surface roughness as described …

Improving Methods For The Successful Establishment Of Switchgrass, Whitney Marie Monin

Theses and Dissertations--Plant and Soil Sciences

Our research investigated whether priming switchgrass seeds with water or ethephon would increase stand establishment in the field. ‘Alamo’ seed germinated faster and grew taller than ‘Cave-in-Rock.Seeds primed for six days in water or for one day in ethephon 10 mM had the greatest seedling densities. In growth chamber environments seed priming were tested to hasten germination velocity. Seeds primed for two, four or six days in water germinated faster than unprimed seeds. Ethephon treatments reduced overall germination and germination velocity. Accent and Accent Q herbicides containing nicosulfuron are used to control weeds. To test ‘Alamo’ sensitivity to these herbicides, …

Soil And Biosolid Nano- And Macro-Colloid Properties And Contaminant Transport Behavior, Jessique L. Ghezzi

Theses and Dissertations--Plant and Soil Sciences

Despite indications that they are potential contaminant transport systems and threats to groundwater quality, very little effort has been invested in comparing contaminant transport behavior of natural environmental nanocolloids and their corresponding macrocolloid fractions in the presence of As, Se, Pb, and Cu contaminants. This study involved physico-chemical, mineralogical, stability and contaminant-transport characterizations of nano- (< 100 nm) and macro-colloids (100-2000 nm) fractionated from three Kentucky soils and one biosolid waste. Particle size was investigated with SEM/TEM and dynamic light scattering. Surface reactivity was estimated using CEC and zeta potential. Mineralogical composition was determined by XRD, FTIR, and thermogravimetric analyses. Sorption isotherms assessed affinities for Cu²⁺, Pb²⁺, AsO₃^-, and SeO₄^-2 contaminants, while settling kinetics experiments of suspensions at 0, 2 and 10 mg/L contaminants determined stability and transportability potential. Undisturbed 18x30 cm KY Ashton Loam soil monoliths were also used for …

Applications Of Epr With An Emphasis On Tau Fibril Structure, Virginia Meyer

Electronic Theses and Dissertations

Substances containing unpaired electrons have been studied by electron paramagnetic resonance (EPR) for nearly 70 years. With continual development and enhancement of EPR techniques, questions have arisen regarding optimum method selection for a given sample based on its properties. In this work, radiation defects, natural lattice defects, solid organic radicals, radicals in solution, and spin-labeled proteins were analyzed using CW, pulse, and rapid scan EPR to compare methods. Studies of solid BDPA, E' in quartz, N_s⁰ in diamond, and a-Si:H, showed that rapid scan could overcome many obstacles presented by other techniques, cementing rapid scan as an effective …

Nanoscale Thermoelectrics: A Study Of The Absolute Seebeck Coefficient Of Thin Films, Sarah J. Mason

Electronic Theses and Dissertations

The worlds demand for energy is ever increasing. Likewise, the environmental impact of climate change due generating that energy through combustion of fossil fuels is increasingly alarming. Due to these factors new sources of renewable energies are constantly being sought out. Thermoelectric devices have the ability to generate clean, renewable, energy out of waste heat. However promising that is, their inefficiency severely inhibits applicability and practical use. The usefulness of a thermoelectric material increases with the dimensionless quantity, ZT, where, Z = S²σ/κ, and S, σ, and κ are the Seebeck coefficient and electrical and thermal …

The Impact Of Enterprise Resource Planning Systems On Small And Medium Enterprises, Miguel Buleje

CCE Theses and Dissertations

Enterprise resource planning (ERP) systems are considered the price of entry in today's business environment, and the number of small and medium-sized enterprises (SME) retiring legacy systems in favor of ERP systems is increasing exponentially.

However, there is a lack of knowledge and awareness of ERP systems and their potential benefit and effect on performance, and overall value to SMEs. While ERP adoption costs and potential benefits are high, it is not apparent whether the end result will translate into higher productivity for SMEs.

The goal of this study is to evaluate the benefits that accrue to a firm on …

An Interpretative Phenomenological Analysis Of Telehealth Champions, Ragan A. Dubose-Morris

CCE Theses and Dissertations

The implementation of telehealth applications is resource intensive and fraught with challenges unique to the people and places involved. The use of telehealth to provide clinical care to patients, educate patients and providers, and conduct research studies to advance medical science has been shown to positively affect issues of access and the quality of care. Previous research has focused on the use of specific technologies, known barriers to adoption and diffusion, and the general efficacy of these applications. Few studies have researched the role champions play in the deployment and operation of telehealth networks. The researcher proposed conducting an interpretative …

The Use Of Liquid Chromatography And Subcritical Fluid Chromatography For Chiral Separations Using Macrocyclic Chiral Stationary Phases: Insights Into Mechanisms Of Retention And Chiral Discrimination, Ross M. Woods

Chemistry & Biochemistry Dissertations

Enantiomeric separations are an essential component of pharmaceutical drug development, not only at the analytical scale, but also to separate usable quantities for further analysis. The field of asymmetric synthesis is also heavily dependent on chromatographic methods to separate and quantitate the results of asymmetric transformations as well as characterize new ligands and catalysts. This dissertation focuses on the use of macrocyclic chiral stationary phases for use in high performance liquid chromatography as well as subcritical fluid chromatography to separate individual enantiomers of molecules of importance to the scientific community. Optimized separation conditions are provided for many of these important …

Fundamental And Applied Studies Of An Ambient Ionization Technique: Continuous Flow-Extractive Desorption Electrospray Ionization - Mass Spectrometry, Li Li

Chemistry & Biochemistry Dissertations

Continuous flow extractive desorption electrospray ionization (CF-EDESI) is a novel ambient ionization technique that was developed to help analyze samples from non-ESI-friendly solvents, manipulate protein charge states, and couple to a flowing sample solution stream. CF-EDESI is performed by introducing a sample solution through a hypodermic needle set orthogonal to an on-axis electrospray ionization source. Samples dissolved in non-ESI-friendly solvents such as hexanes, ethyl acetate etc. can be successfully detected in CF-EDESI which then makes it an attractive detection technique for normal phase separation. Additionally, introducing samples separated from electrospray has provided freedom to optimize both the sample solvents and …