Physical Sciences and Mathematics Commons^™

Automated Midline Shift Detection On Brain Ct Images For Computer-Aided Clinical Decision Support, Xuguang Qi

Theses and Dissertations

Midline shift (MLS), the amount of displacement of the brain’s midline from its normal symmetric position due to illness or injury, is an important index for clinicians to assess the severity of traumatic brain injury (TBI). In this dissertation, an automated computer-aided midline shift estimation system is proposed. First, a CT slice selection algorithm (SSA) is designed to automatically select a subset of appropriate CT slices from a large number of raw images for MLS detection. Next, ideal midline detection is implemented based on skull bone anatomical features and global rotation assumptions. For the actual midline detection algorithm, a window …

Investigating The Potential Applications Of A Raman Tweezer System, John Wray

Theses and Dissertations

This thesis describes the construction of an Optical Tweezer apparatus to be used in conjunction with a confocal Raman spectrometer. The tweezer utilizes an infrared (λ=1064 nm) laser directed into an inverted microscope with NA=1.4 oil immersion 100x objective lens that strongly focuses the laser light into a sample to function as a single-beam gradient force trap. The long term goal of this research program is to develop a single molecule Raman tweezers apparatus that allows one to control the position of a Raman nanoplasmonic amplifier. This thesis describes the construction of the Raman tweezer apparatus along with several Raman …

Exploiting Rogue Signals To Attack Trust-Based Cooperative Spectrum Sensing In Cognitive Radio Networks, David Jackson

Theses and Dissertations

Cognitive radios are currently presented as the solution to the ever-increasing spectrum shortage problem. However, their increased capabilities over traditional radios introduce a new dimension of security threats. Cooperative Spectrum Sensing (CSS) has been proposed as a means to protect cognitive radio networks from the well known security threats: Primary User Emulation (PUE) and Spectrum Sensing Data Falsification (SSDF). I demonstrate a new threat to trust-based CSS protocols, called the Rogue Signal Framing (RSF) intrusion. Rogue signals can be exploited to create the illusion of malicious sensors which leads to the framing of innocent sensors and consequently, their removal from …

Analysis Of Defects In Gan Using Hybrid Density Functional Theory, Ibrahima Castillo Diallo

Theses and Dissertations

In this thesis, we first present a brief overview of various theoretical approaches used to examine the electronic structure of defects in GaN. Using the recently developed hybrid density functional theory (HSE06) along with the experimental measurements, we propose a new explanation of the nature of the yellow luminescence band in carbon-doped GaN. We conduct a systematic study of electronic and optical properties of defects (Carbon, Oxygen, Silicon related) that are candidates for the origin of yellow luminescence. We show that the CN-ON complex is significantly more likely to form compared to isolated carbon configurations. In contrast to the properties …

Reforestation Of Red Spruce (Picea Rubens) On The Cheat Mountain Range, West Virginia, Justin Madron

Theses and Dissertations

The (Plethodon nettingi) Cheat Mountain Salamander is a rare and endangered species that relies heavily on (Picea rubens) Red Spruce for habitat. P. rubens communities on the Cheat Mountain range in West Virginia have been disturbed by fires and logging, and regeneration of P. rubens stands are central to the survival of the P. netting. A supervised and unsupervised landscape classification of three Landsat images over the past 26 years was conducted to analyze change in P. rubens communities on Cheat Mountain Range. Change detection results revealed that from 1986-2012 a 52% growth increase of P. rubens stands, 18% loss, …

A Weak Groethendieck Compactness Principle For Infinite Dimensional Banach Spaces, Kaitlin Bjorkman

Theses and Dissertations

The goal of this thesis is to give an exposition of the following recent result of Freeman, Lennard, Odell, Turett and Randrianantoanina. A Banach space has the Schur property if and only if every weakly compact set is contained in the closed convex hull of a weakly null sequence. This result complements an old result of Grothendieck (now called the Grothendieck Compactness Principle) stating that every norm compact subset of a Banach space is contained in the closed convex hull of a norm null sequence. We include many of the relevant definitions and preliminary results which are required in the …

Uniqueness Of Bipartite Factors In Prime Factorizations Over The Direct Product Of Graphs, Owen Puffenberger

Theses and Dissertations

While it has been known for some time that connected non-bipartite graphs have unique prime factorizations over the direct product, the same cannot be said of bipartite graphs. This is somewhat vexing, as bipartite graphs do have unique prime factorizations over other graph products (the Cartesian product, for example). However, it is fairly easy to show that a connected bipartite graph has only one prime bipartite factor, which begs the question: is such a prime bipartite factor unique? In other words, although a connected bipartite graph may have multiple prime factorizations over the direct product, do such factorizations contain the …

Actual Entities: A Control Method For Unmanned Aerial Vehicles, Erica Absetz

Theses and Dissertations

The focus of this thesis is on Actual Entities, a concept created by the philosopher Alfred North Whitehead, and how the concept can be applied to Unmanned Aerial Vehicles as a behavioral control method. Actual Entities are vector based, atomic units that use a method called prehension to observe their environment and react with various actions. When combining multiple Actual Entities a Colony of Prehending Entities is created; when observing their prehensions an intelligent behavior emerges. By applying the characteristics of Actual Entities to Unmanned Aerial Vehicles, specifically in a situation where they are searching for targets, this emergent, intelligent …

Choosing The Cut Point For A Restricted Mean In Survival Analysis, A Data Driven Method, Emily H. Sheldon

Theses and Dissertations

Survival Analysis generally uses the median survival time as a common summary statistic. While the median possesses the desirable characteristic of being unbiased, there are times when it is not the best statistic to describe the data at hand. Royston and Parmar (2011) provide an argument that the restricted mean survival time should be the summary statistic used when the proportional hazards assumption is in doubt. Work in Restricted Means dates back to 1949 when J.O. Irwin developed a calculation for the standard error of the restricted mean using Greenwood’s formula. Since then the development of the restricted mean has …

Detecting And Correcting Batch Effects In High-Throughput Genomic Experiments, Sarah Reese

Theses and Dissertations

Batch effects are due to probe-specific systematic variation between groups of samples (batches) resulting from experimental features that are not of biological interest. Principal components analysis (PCA) is commonly used as a visual tool to determine whether batch effects exist after applying a global normalization method. However, PCA yields linear combinations of the variables that contribute maximum variance and thus will not necessarily detect batch effects if they are not the largest source of variability in the data. We present an extension of principal components analysis to quantify the existence of batch effects, called guided PCA (gPCA). We describe a …

Formation Mechanisms And Photocatalytic Properties Of Zno-Based Nanomaterials, Natalie Herring

Theses and Dissertations

Zinc Oxide (ZnO) is one of the most extensively studied semiconductors because of its unique properties, namely, its wide band gap (3.37 eV) and high excitation binding energy (60 meV). These properties make ZnO a promising material for uses in a broad range of applications including sensors, catalysis and optoelectronic devices. The presented research covers a broad spectrum of these interesting nanomaterials, from their synthesis and characterization to their use as photocatalyts. A new synthetic approach for producing morphology controlled ZnO nanostructures was developed using microwave irradiation (MWI). The rapid decomposition of zinc acetate in the presence of a mixture …

Multiple-Instance And One-Class Rule-Based Algorithms, Dat Nguyen

Theses and Dissertations

In this work we developed rule-based algorithms for multiple-instance learning and one-class learning problems, namely, the mi-DS and OneClass-DS algorithms. Multiple-Instance Learning (MIL) is a variation of classical supervised learning where there is a need to classify bags (collection) of instances instead of single instances. The bag is labeled positive if at least one of its instances is positive, otherwise it is negative. One-class learning problem is also known as outlier or novelty detection problem. One-class classifiers are trained on data describing only one class and are used in situations where data from other classes are not available, and also …

Graphene-Based Semiconductor And Metallic Nanostructured Materials, Abdallah Zedan

Theses and Dissertations

Exciting periods of scientific research are often associated with discoveries of novel materials. Such period was brought about by the successful preparation of graphene which is a 2D allotrope of carbon with remarkable electronic, optical and mechanical properties. Functional graphene-based nanocomposites have great promise for applications in various fields such as energy conversion, opteoelectronics, solar cells, sensing, catalysis and biomedicine. Herein, microwave and laser-assisted synthetic approaches were developed for decorating graphene with various semiconductor, metallic or magnetic nanostructures of controlled size and shape. We developed a scalable microwave irradiation method for the synthesis of graphene decorated with CdSe nanocrystals of …

Characterization Of A Weighted Quantile Score Approach For Highly Correlated Data In Risk Analysis Scenarios, Caroline Carrico

Theses and Dissertations

In risk evaluation, the effect of mixtures of environmental chemicals on a common adverse outcome is of interest. However, due to the high dimensionality and inherent correlations among chemicals that occur together, the traditional methods (e.g. ordinary or logistic regression) are unsuitable. We extend and characterize a weighted quantile score (WQS) approach to estimating an index for a set of highly correlated components. In the case with environmental chemicals, we use the WQS to identify “bad actors” and estimate body burden. The accuracy of the WQS was evaluated through extensive simulation studies in terms of validity (ability of the WQS …

Accounting For Model Uncertainty In Linear Mixed-Effects Models, Adam Sima

Theses and Dissertations

Standard statistical decision-making tools, such as inference, confidence intervals and forecasting, are contingent on the assumption that the statistical model used in the analysis is the true model. In linear mixed-effect models, ignoring model uncertainty results in an underestimation of the residual variance, contributing to hypothesis tests that demonstrate larger than nominal Type-I errors and confidence intervals with smaller than nominal coverage probabilities. A novel utilization of the generalized degrees of freedom developed by Zhang et al. (2012) is used to adjust the estimate of the residual variance for model uncertainty. Additionally, the general global linear approximation is extended to …

Hydration Of The Pyrimidine Radical Cation And Stepwise Solvation Of Protonated Pyrimidine With Water, Methanol, And Acetonitrile, Ahmed M. Hamid, Pramod Sharma, M. Samy El-Shall, Rifaat Hilal, Shaaban Elroby, Saadullah G. Aziz, Abdulrahman O. Alyoubi

Chemistry Publications

Equilibrium thermochemical measurements using an ion mobility drift cell technique have been utilized to investigate the binding energies and entropy changes associated with the stepwise hydration of the biologically significant ions pyrimidine radical cation and protonated pyrimidine. The binding energy of the hydrated pyrimidine radical cation is weaker than that of the proton-bound dimer pyrimidineH+(H2O) consistent with the formation of a weak carbon-based CHδ+··OH2 hydrogen bond (11.9 kcal/mol) and a stronger NH+··OH2 hydrogen bond (15.6 kcal/mol), respectively. Other proton-bound dimers such as pyrimidineH+(CH3OH) and pyrimidineH+(CH3CN) exhibit higher binding energies (18.2 kcal/mol and 22.8 kcal/mol, respectively) due to the higher proton …

Journal Of Mathematics And Science: Collaborative Explorations

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

Scientific Argumentation As A Foundation For The Design Of Inquiry-Based Science Instruction, A. Falk, L. Brodsky

Journal of Mathematics and Science: Collaborative Explorations

Despite the attention that inquiry has received in science education research and policy, a coherent means for implementing inquiry in the classroom has been missing [1]. In recent research, scientific argumentation has received increasing attention for its role in science and in science education [2]. In this article, we propose that organizing a unit of instruction around building a scientific argument can bring inquiry practices together in the classroom in a coherent way. We outline a framework for argumentation, focusing on arguments that are central to science—arguments for the best explanation. We then use this framework as the basis for …

Infusing Problem-Based Learning (Pbl) Into Science Methods Courses Across Virginia, K. R. Thomas, P. L. Horne, S. M. Donnelly, C. T. Berube

Journal of Mathematics and Science: Collaborative Explorations

This article outlines the results of a collaborative study of the effects of infusing problem-based learning (PBL) into K-12 science methods courses across four universities in Virginia. Changes in pre-service teachers' attitudes surrounding science teaching were measured before and after completing a science methods course in which they experienced PBL first-hand as participants, and then practiced designing their own PBL units for use in their future classrooms. The results indicate that exposure to PBL enhances pre-service teachers' knowledge of inquiry methods and self-efficacy in teaching science.

Inquiry Teaching: It Is Easier Than You Think!, S. Key, D. Owens

Journal of Mathematics and Science: Collaborative Explorations

This article is a survey of the literature on inquiry teaching. Many teachers do not participate in inquiry teaching for various reasons. The following are the main reasons: it takes too much time; students do not learn what they need for the state test; and, the teachers do not know how to grade projects and presentations. These reasons sound like rhetoric from long ago, but it is very current. In this article, research is used to show that students who participate in inquiry learning or any type of problem-based education do much better than students who do not have that …

Strong Support For Mathematics Specialists In Virginia, J. Singleton, D. Blount

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

Dynamics At A Janus Interface, M. Von Domaros, D. Bratko, B. Kirchner, A. Luzar

Chemistry Publications

Electric field effects on water interfacial properties abound, ranging from electrochemical cells to nanofluidic devices to membrane ion channels. On the nanoscale, spontaneous orientational polarization of water couples with field alignment, resulting in an asymmetric wetting behavior of opposing surfacesa field-induced analogue of a chemically generated Janus interface. Using atomistic simulations, we uncover a new and significant field polarity (sign) dependence of the dipolar- orientation polarization dynamics in the hydration layer. Applying electric fields across a nanoparticle, or a nanopore, can lead to close to 2 orders of magnitude difference in response times of water polarization at opposite surfaces. Typical …

Hydroxyl-Decorated Graphene Systems As Candidates For Organic Metal-Free Ferroelectrics, Multiferroics, And High-Performance Proton Battery Cathode Materials, Menghao Wu, J. D. Burton, Evgeny Y. Tsymbal, Xiao Cheng Zeng, Puru Jena

Physics Publications

Using a first-principles method we show that graphene based materials, functionalized with hydroxyl groups, constitute a class of multifunctional, lightweight, and nontoxic organic materials with functional properties such as ferroelectricity, multiferroicity, and can be used as proton battery cathode materials. For example, the polarizations of semihydroxylized graphane and graphone, as well as fully hydroxylized graphane, are much higher than any organic ferroelectric materials known to date. Further, hydroxylized graphene nanoribbons with proton vacancies at the end can have much larger dipole moments. They may also be applied as high-capacity cathode materials with a specific capacity that is six times larger …

The Effect Of Sulfur Covalent Bonding On The Electronic Shells Of Silver Clusters, Anthony F. Pedicini, Arthur C. Reber, Shiv N. Khanna

Physics Publications

The nature of the bonding in Ag n S m ^0/− clusters, n = 1–7; m = 1–4, has been analyzed to understand its effect on the electronic shell structure of silver clusters. First-principle investigations reveal that the sulfur atoms prefer 2 or 3-coordinate sites around a silver core, and that the addition of sulfur makes the planar structures compact. Molecular orbital analysisfinds that the 3p orbitals of sulfur form a bonding orbital and two weakly bonding lone pairs withsilver. We examine the electronic shell structures of Ag 6Sm, which are two electrons deficient of a spherical closed electronic shell …

Communication: In Search Of Four-Atom Chiral Metal Clusters, Xinxing Zhang, Bradley Visser, Martin Tschurl, Evan Collins, Yi Wang, Qian Wang, Yawei Li, Qiang Sun, Puru Jena, Gerd Gantefoer, Ulrich Boesl, Ulrich Heiz, Kit H. Bowen Jr.

Physics Publications

A combined study utilizing anion photoelectron spectroscopy and density functional theory was conducted to search for four-atom, chiral, metal, and mostly metal clusters. The clusters considered were AuCoMnBi−/0, AlAuMnO−/0, AgMnOAl−/0, and AuAlPtAg−/0, where the superscripts, −/0, refer to anionic and neutral cluster species, respectively. Based on the agreement of experimentally and theoretically determined values of both electron affinities and vertical detachment energies, the calculated cluster geometries were validated and examined for chirality. Among both anionic and neutral clusters, five structures were identified as beingchiral.

Magnetic Properties Of Co2-Xtmxc And Co3-Xtmxc Nanoparticles, Meichun Qian, Shiv N. Khanna

Physics Publications

Using synthetic chemical approaches, it is now possible to synthesize transition metal carbides nanoparticles with morphology, where the transition metal layers are embedded with intervening layers of carbon atoms. A composite material consisting of Co2C and Co3C nanoparticles has been found to exhibit unusually large coercivity and energy product. Here, we demonstrate that the magnetic moments and the anisotropy can be further enhanced by using a combination of Co and other transition metals (TM). Our studies are based on mixednanoparticles Co2−x TM xC and Co3−x TM xC, in which selected Co sites are replaced with 3d transition elements Cr, Mn, …

Structure And Properties Of Mn4cl9: An Antiferromagnetic Binary Hyperhalogen, Yawei Li, Shunhong Zhang, Qian Wang, Puru Jena

Physics Publications

Calculations based on density functional theory show that the structure of Mn₄Cl₉ anion is that of a Mn atom at the core surrounded by three MnCl₃ moieties. Since Mn is predominantly divalent and MnCl₃ is known to be a superhalogen with a vertical detachment energy (VDE) of 5.27 eV, Mn₄Cl₉ can be viewed as a hyperhalogen with the formula unit Mn(MnCl₃)₃. Indeed, the calculated VDE of Mn₄Cl₉ anion, namely 6.76 eV, is larger than that of MnCl₃ anion. More importantly, unlike previously discovered hyperhalogens, …

An All-Electron Density Functional Theory Study Of The Structure And Properties Of The Neutral And Singly Charged M-12 And M-13 Clusters: M = Sc-Zn, G. L. Gutsev, C. W. Weatherford, K. G. Belay, B. R. Ramachandran, P. Jena

Physics Publications

The electronic and geometrical structures of the M ₁₂ and M ₁₃ clusters where M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn along with their singly negatively and positively charged ions are studied using all-electron density functional theory within the generalized gradient approximation. The geometries corresponding to the lowest total energy states of singly and negatively charged ions of V₁₃, Mn₁₂, Co₁₂, Ni ₁₃, Cu ₁₃, Zn ₁₂, and Zn ₁₃ are found to be different from the geometries of the corresponding neutral parents. The computed …

Executive Summary — Teaching About Scientific Inquiry And The Nature Of Science

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

Quantification Of Biomass And Cell Motion In Human Pluripotent Stem Cell Colonies, Thomas A. Zangle, Jennifer Chun, Jin Zhang, Jason C. Reed, Michael A. Teitell

Physics Publications

Abstract

Somatic cell reprogramming to pluripotency requires an immediate increase in cell proliferation and reduction in cell size. It is unknown whether proliferation and biomass controls are similarly coordinated with early events during the differentiation of pluripotent stem cells (PSCs). This impasse exists because PSCs grow in tight clusters or colonies, precluding most quantifying approaches. Here, we investigate live cell interferometry as an approach to quantify the biomass and growth of HSF1 human PSC colonies before and during retinoic acid-induced differentiation. We also provide an approach for measuring the rate and coordination of intracolony mass redistribution in HSF1 clusters using …