Physical Sciences and Mathematics Commons^™

A Plotless Density Estimator Based On The Asymptotic Limit Of Ordered Distance Estimation Values, Barry J. Kronenfeld

Barry J. Kronenfeld

Estimation of tree density from point-tree distances is an attractive option for quick inventory of new sites, but estimators that are unbiased in clustered and dispersed situations have not been found. Noting that bias of an estimator derived from distances to the kth nearest neighbor from a random point tends to decrease with increasing k, a method is proposed for estimating the limit of an asymptotic function through a set of ordered distance estimators. A standard asymptotic model is derived from the limiting case of a clustered distribution. The proposed estimator is evaluated against 13 types of simulated generating processes, …

Detecting Differentially Expressed Genes While Controlling The False Discovery Rate For Microarray Data, Shuo Jiao

Department of Statistics: Dissertations, Theses, and Student Work

Microarray is an important technology which enables people to investigate the expression levels of thousands of genes at the same time. One common goal of microarray data analysis is to detect differentially expressed genes while controlling the false discovery rate. This dissertation consists with four papers written to address this goal. The dissertation is organized as follows: In Chapter 1, a brief introduction of the Affymetrix GeneChip microarray technology is provided. The concept of differentially expressed genes and the definition of the false discovery rate are also introduced. In Chapter 2, a literature review of the related works on this …

Automatic Graphics And Game Content Generation Through Evolutionary Computation, Erin Hastings

Electronic Theses and Dissertations

Simulation and game content includes the levels, models, textures, items, and other objects encountered and possessed by players during the game. In most modern video games and simulation software, the set of content shipped with the product is static and unchanging, or at best, randomized within a narrow set of parameters. However, ideally, if game content could be constantly and automatically renewed, players would remain engaged longer in the evolving stream of content. This dissertation introduces three novel technologies that together realize this ambition. (1) The first, NEAT Particles, is an evolutionary method to enable users to quickly and easily …

Dense Spectral Beam Combining With Volume Bragg Gratings In Photo-Thermo-Refractive Glass, Oleksiy Andrusyak

Electronic Theses and Dissertations

Beam combining techniques have become an important tool in the design of high-power high-brightness laser systems. Spectral beam combining (SBC) is an incoherent combining technique that does not require phase control of sources, allowing for a stable and robust system. Using SBC, beams from an array of lasers with each element operated at a different wavelength are combined into a single near-diffraction-limited beam with the same aperture using dispersive optical elements. SBC by means of volume Bragg gratings (VBGs) utilizes unique spectral response of VBGs: diffraction efficiency is close to unity when the Bragg condition is satisfied and is close …

Design, Analysis, And Optimization Of Diffractive Optical Elements Under High Numerical Aperture Focusing, Toufic Jabbour

Electronic Theses and Dissertations

The demand for high optical resolution has brought researchers to explore the use of beam shaping diffractive optical elements (DOEs) for improving performance of high numerical aperture (NA) optical systems. DOEs can be designed to modulate the amplitude, phase and/or polarization of a laser beam such that it focuses into a targeted irradiance distribution, or point spread function (PSF). The focused PSF can be reshaped in both the transverse focal plane and along the optical axis. Optical lithography, microscopy and direct laser writing are but a few of the many applications in which a properly designed DOE can significantly improve …

Nonlinear Laser Energy Depletion In Laser-Plasma Accelerators, Bradley Allan Shadwick, Carl B. Schroeder, Eric Esarey

Department of Physics and Astronomy: Faculty Publications

Energy depletion of intense, short-pulse lasers via excitation of plasma waves is investigated numerically and analytically. The evolution of a resonant laser pulse proceeds in two phases. In the first phase, the pulse steepens, compresses, and frequency redshifts as energy is deposited in the plasma. The second phase of evolution occurs after the pulse reaches a minimum length at which point the pulse rapidly lengthens, losing resonance with the plasma. Expressions for the rate of laser energy loss and rate of laser redshifting are derived and are found to be in excellent agreement with the direct numerical solution of the …

A Wide-Angle Electron Grating Bi-Prism Beam Splitter, Adam Caprez, Roger Bach, Scot Mcgregor, Herman Batelaan

Department of Physics and Astronomy: Faculty Publications

We demonstrate a wide-angle electron beam splitter capable of producing 1 cm beam separation at the detection plane. The beam splitter utilizes a nanofabricated periodic grating in combination with a bi-prism element. In contrast to devices utilizing only bi-prism elements, the use of the periodic grating causes amplitude, and not wavefront, splitting. Even at maximum separation, beam profiles remain undistorted, providing evidence that coherence is intact. This is a step towards the realization of a large area electron interferometer using such a grating bi-prism combination.

Nonlinear Dynamics Of Infant Sitting Postural Control, Joan E. Deffeyes

Department of Psychology: Dissertations, Theses, and Student Research

Sitting is one of the first developmental milestones that an infant achieves. Thus measurements of sitting posture present an opportunity to assess sensorimotor development at a young age, in order to identify infants who might benefit from therapeutic intervention, and to monitor the efficacy of the intervention. Sitting postural sway data was collected using a force plate from infants with typical development, and from infants with delayed development, where the delay in development was due to cerebral palsy in most of the infants in the study. The center of pressure time series from the infant sitting was subjected to a …

A Tikz Tutorial: Generating Graphics In The Spirit Of Tex, Andrew Mertz, William Slough

Faculty Research and Creative Activity

TikZ is a system which can be used to specify graphics of very high quality. For example, accurate place- ment of picture elements, use of TEX fonts, ability to incorporate mathematical typesetting, and the possi- bility of introducing macros can be viewed as positive factors of this system. The syntax uses an amal- gamation of ideas from METAFONT, METAPOST, PSTricks, and SVG, allowing its users to \program" their desired graphics. The latest revision to TikZ introduces many new features to an already feature- packed system, as evidenced by its 560-page user manual. Here, we present a tutorial overview of this …

Transport Of Dust And Anthropogenic Aerosols Across Alexandria, Egypt, Hesham El-Askary, R. Farouk, C. Ichoku, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

The flow of pollutants from Europe and desert dust to Europe from the Sahara desert both affects the air quality of the coastal regions of Egypt. As such, measurements from both ground and satellite observations assume great importance to ascertain the conditions and flow affecting the Nile Delta and the large city of Alexandria. We note that special weather conditions prevailing in the Mediterranean Sea result in a westerly wind flow pattern during spring and from North to South during the summer. Such flow patterns transport dust-loaded and polluted air masses from the Sahara desert and Europe, respectively, through Alexandria, …

Book Review: Cyber Security And Global Information Assurance: Threat Analysis And Response Solutions, Gary C. Kessler

Publications

This document is Dr. Kessler's review of Cyber Security and Global Information Assurance: Threat Analysis and Response Solutions, edited by Kenneth J. Knapp. Information Science Reference, 2009. ISBN: 978-1-60566-326-5.

Tetranuclear Group 7/8 Mixed-Metal And Open Trinuclear Group 7 Metal Carbonyl Clusters Bearing Bridging 2-Mercapto-1-Methylimidazole Ligands, Shishir Ghosh, Shariff E. Kabir, Salina Pervin, Arun K. Raha, G. M. Golzar Hossain, Daniel T. Haworth, Sergey V. Lindeman, Dennis W. Bennett, Tasneem Siddiquee, Luca Salassa, Herbert W. Roesky

Chemistry Faculty Research and Publications

The reactivity of group 7 metal dinuclear carbonyl complexes [M₂(CO)₆(μ-SN₂C₄H₅)₂] (1, M = Re; 2, M = Mn) toward group 8 metal trinuclear carbonyl clusters were examined. Reactions of 1 and 2 with [Os₃(CO)₁₀(NCMe)₂] in refluxing benzene furnished the tetranuclear mixed-metal clusters [Os₃Re(CO)₁₃(μ₃-SN₂C₄H₅)] (3) and [Os₃Mn(CO)₁₃(μ₃-SN₂C₄H₅)] (4), respectively. Similar treatment of …

Carbon−Phosphorus Bond Activation Of Tri(2-Thienyl)Phosphine At Dirhenium And Dimanganese Centers, Md. Nazim Uddin, M. Abdul Mottalib, Noorjahan Begum, Shishir Ghosh, Arun K. Raha, Daniel T. Haworth, Sergey V. Lindeman, Tasneem Siddiquee, Dennis W. Bennett, Graeme Hogarth, Ebbe Nordlander, Shariff E. Kabir

Chemistry Faculty Research and Publications

Reaction of [Re₂(CO)₉(NCMe)] with tri(2-thienyl)phosphine (PTh₃) in refluxing cyclohexane affords three substituted dirhenium complexes: [Re₂(CO)₉(PTh₃)] (1), [Re₂(CO)₈(NCMe)(PTh₃)] (2), and [Re₂(CO)₈(PTh₃)₂] (3). Complex 2 was also obtained from the room-temperature reaction of [Re₂(CO)₈(NCMe)₂] with PTh₃ and is an unusual example in which the acetonitrile and phosphine ligands are coordinated to the same rhenium atom. Thermolysis of 1 and 3 in refluxing xylene …

Substrate Induced Structural And Dynamics Changes In Human Phosphomevalonate Iinase And Implications For Mechanism, Andrew Lawrence Olson, Huili Yao, Timothy J. Herdendorf, Henry M. Miziorko, Supa Hannongbua, Patchareenat Saparpakom, Sheng Cai, Daniel S. Sem

Chemistry Faculty Research and Publications

Phosphomevalonate kinase (PMK) catalyzes an essential step in the mevalonate pathway, which is the only pathway for synthesis of isoprenoids and steroids in humans. PMK catalyzes transfer of the γ-phosphate of ATP to mevalonate 5-phosphate (M5P) to form mevalonate 5-diphosphate. Bringing these phosphate groups in proximity to react is especially challenging, given the high negative charge density on the four phosphate groups in the active site. As such, conformational and dynamics changes needed to form the Michaelis complex are of mechanistic interest. Herein, we report the characterization of substrate induced changes (Mg-ADP, M5P, and the ternary complex) in PMK using …

Controlled Functionalization Of Crystalline Polyolefins And Their Application In Soluble Polymer Support, Jihoon Shin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Functionalization of polyolefins has been recognized as a useful methodology for the generation of new materials with a wide range of applications. Recently, crystalline or semi-crystalline polyolefins have drawn increasing attention in both industrial and academic fields as one of the most interesting engineering plastics, due to their remarkable physical and mechanical properties. This dissertation describes: (1) novel methods for the direct postfunctionalization of crystalline polyolefins to introduce functionality, (2) characterizations for the functionalized polymers to analyze their structures, molecular-weight properties, thermal properties, and hydrophilicity, and (3) an application of the modified crystalline polystyrene as a soluble polymer support for …

Statistical Inferences For Functions Of Parameters Of Several Pareto And Exponential Populations With Application In Data Traffic, Sumith Gunasekera

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this dissertation, we discuss the usability and applicability of three statistical inferential frameworks--namely, the Classical Method, which is sometimes referred to as the Conventional or the Frequentist Method, based on the approximate large sample approach, the Generalized Variable Method based on the exact generalized p -value approach, and the Bayesian Method based on prior densities--for solving existing problems in the area of parametric estimation. These inference procedures are discussed through Pareto and exponential distributions that are widely used to model positive random variables relevant to social, scientific, actuarial, insurance, finance, investments, banking, and many other types of observable phenomena. …

X-Ray Diffraction Study Of Dysprosium Single Crystal Samples In A Diamond Anvil Cell (Dac), Ognjen Grubor-Urosevic

UNLV Theses, Dissertations, Professional Papers, and Capstones

X-ray diffraction is the basis of crystallography, the study of the structure of crystals. It uses X-rays of a wavelength on the order of the size of atoms, so it can resolve the positions of individual atoms in a crystal. Illuminating the crystal with a well-collimated X-ray beam produces X-rays diffracted in a certain direction for a specific crystal orientation. By analyzing the relative phase of the incoming and outgoing scattered X-rays, the unique arrangements of atoms can be determined and the structure of the crystal can be solved.

There is a long standing controversy regarding the crystal structures and …

Evaluation Of Extraction Chromatography Resins For Rapid Actinide Analysis, Julie Marisa Gostic

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this work, physical and chemical parameters associated with extraction chromatography separation procedures were investigated for rapid actinide analysis. A vacuum box system was designed in-house and was characterized in terms of flow rate reproducibility, matrix effects on flow rate for sequential elution, and actinide separation efficiency using different types of resin (TEVA, DGA and TRU). Results indicated that the columnar kinetics of the resins were sufficiently rapid to run high purity samples through the unit over a wide range of flow rates for all resin types. Single matrix interferences at a metal ion ratio of 1:10 6 relative to …

Optimization Of Solid Oxide Fuel Cell Interconnect Design, Krishna C. Pulagam

UNLV Theses, Dissertations, Professional Papers, and Capstones

Performance of solid oxide fuel cells (SOFC) is dependent of a set of complex physical and chemical processes occurring simultaneously. Interconnect for SOFC is important as it provides electrical connection between anode of one individual cell to the cathode of neighboring one. It also acts as a physical barrier to protect the air electrode material from the reducing environment of the fuel on the fuel electrode side, and it equally prevents the fuel electrode material from contacting with oxidizing atmosphere of the oxidant electrode side. A three-dimensional numerical model has been developed to evaluate the SOFC including the current collector, …

Ac Susceptibility And Heat Capacity Studies Of The Geometrically Frustrated Pyrochlores Terbium Titanium Tin Oxides And Holmium Titanates, Daniel Antonio

UNLV Theses, Dissertations, Professional Papers, and Capstones

Materials with a geometrically frustrated magnetic pyrochlore lattice have been of interest due to their unusual ground states. Tb 2 Ti 2 O 7 is known for having a spin liquid ground state which does not transition to a long-range ordered state down to at least 50 mK. Ho 2 Ti 2 O 7 has a macroscopically degenerate spin ice ground state which resembles that of the proton ordering in water ice. Heat Capacity measurements of Tb 2 Ti 2- x Sn x O 7 were done down to 0.36 K and AC magnetic susceptibility measurements of Ho 2- x …

Characterization Of Iron Oxide Thin Films For Photoelectrochemical Hydrogen Production, Kyle Eustace Nelson George

UNLV Theses, Dissertations, Professional Papers, and Capstones

Solar energy is the most sustainable source of energy available. However, solar applications such as photovoltaic cells represent only a partial solution to weaning our dependence upon fossil fuels. Several methods of storing solar energy are currently being pursued, and chemical storage stands out as a promising option - combining design simplicity with high energy density, with hydrogen being particularly attractive because of its abundance and inherently clean nature. A monolithic Photoelectrochemical (PEC) device that produces hydrogen by electrolyzing water directly from sunlight has the benefit of utilizing "free" solar energy to drive the reaction.

Although α-Fe 2 O 3 …

Analytical Method Development For Determination Of Volatile Organic Compounds In Calcareous Desert Soil, Mary F. Turner

UNLV Theses, Dissertations, Professional Papers, and Capstones

Soil sample preservation for volatile organic compound analysis generally requires short sample holding times or preservation of the sample's chemical constituents with sodium bisulfate (NaHSO 4 ). Calcareous soils cannot be preserved using NaHSO4 because effervescence will promote the loss of analytes, and short holding times before analysis are not practical for remote sampling locations. An experimental approach was developed for determination of volatile organic compounds (VOCs) in soil that utilizes solid sorbents for sample preservation and solid-phase microextraction (SPME) sample preparation technique coupled with gas chromatography/mass spectrometry (GC/MS) for analysis. Solid sorbents are used to sequester readily extractable (vapor …

Mutation Of H63 And Its Catalytic Affect On The Methionine Aminopeptidase From Escherichia Coli, Sanghamitra Mitra, Brian Bennett, Richard C. Holz

Physics Faculty Research and Publications

In order to gain insight into the mechanistic role of a flexible exterior loop near the active site, made up of Y62, H63, G64, and Y65, that has been proposed to play an important role in substrate binding and recognition in the methionyl aminopeptidase from Escherichia coli (EcMetAP-I), the H63A enzyme was prepared. Mutation of H63 to alanine does not affect the ability of the enzyme to bind divalent metal ions. The specific activity of H63A EcMetAP-I was determined using four different substrates of varying lengths, namely, l-Met-p-NA, MAS, MGMM and MSSHRWDW. For the smallest/shortest …

Calculating The Volume Of The May 18, 1980 Eruption Of Mount St. Helens, Dâvid Nuñez Wickham

Environmental Science and Management Professional Master's Project Reports

The May 18, 1980 eruption of Mount St. Helens created a massive amount of sediment and debris, thought to be as much as 5.5 billion cubic yards. This sediment causes infill of river stretches and collects along levees protecting southwest Washington State. The sediment must be removed to ensure these areas do not flood. The US Army Corps of Engineers (USACOE) is tasked with flood protection for southwest Washington State and the levees protecting the cities of Castle Rock, Lexington, Kelso, and Longview. The Sediment Retention Dam, opened in 1989 is able to filter out larger particulate but fine grain …

Downspout Disconnection Suitability And Incentives Analysis For The City Of Gresham, Oregon, Brian C. Fletcher

Environmental Science and Management Professional Master's Project Reports

The City of Gresham is developing a Downspout Disconnection Program, which encourages homeowners to disconnect their roof downspouts from the storm sewer system and divert the stormwater onto their lawn or rain garden. Downspout disconnection is being evaluated for its effectiveness to help the city meet stormwater discharge requirements in their NPDES-MS4 permit from Oregon DEQ. This study reviewed current Natural Resources Conservation Service (NRCS) soil data and developed a suitability map showing High, Medium and Low suitability zones for on-site stormwater management. To validate the map, 55 soil textural classes and 11 infiltration rates were determined at residences throughout …

Study Of Corrosion Of Materials In The Sulfur-Iodine Hydrogen Production Cycle, Thao Trung Ho

UNLV Theses, Dissertations, Professional Papers, and Capstones

Hydrogen is of great interest since the availability of traditional fossil fuels is in decline. Strictly speaking, hydrogen is not a primary source of energy but is an energy carrier, since energy typically must be used from another source (electricity, natural gas, coal, etc.) to produce it. Of hydrogen production techniques, the Sulfur-Iodine thermochemical water splitting process (S-I cycle), which was proposed by General Atomics (GA), is promising with its simplicity and high efficiency. Most of the chemicals are recycled except water. However, the S-I cycle operates in a harsh, corrosive environment in the presence of a mixture of iodine …

High Pressure Phase Transistions In The Lanthanide Sesquioxides, Jason Patrick Mcclure

UNLV Theses, Dissertations, Professional Papers, and Capstones

Crystallizing into 5 known polymorphic forms, the rare-Earth sesquioxides RE 2 O 3 represent a family of 4-f electron compounds that have been the subject of study for many years. Aspects of the systematics in the structural phase transitions for RE 2 O 3 (RE=La, Sm, Eu, Gd, Y, Er, Yb, Lu) under pressure were studied using diamond anvil cells (DACs). As a part of this study, detailed equation of state (EOS) data for all these compounds were obtained through the use of angle-dispersive x-ray diffraction (XRD) where anomalies in compression data led to the detailed investigation into one particular …

Enhanced Pre-Monsoon Warming Over The Himalayan-Gangetic Region From 1979-2007, Ritesh Gautam, N. C. Hsu, K. M. Lau, S.-C. Tsay, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Fundamental to the onset of the Indian Summer Monsoon is the land-sea thermal gradient from the Indian Ocean to the Himalayas-Tibetan Plateau (HTP). The timing of the onset is strongly controlled by the meridional tropospheric temperature gradient due to the rapid premonsoon heating of the HTP compared to the relatively cooler Indian Ocean. Analysis of tropospheric temperatures from the longest available record of microwave satellite measurements reveals widespread warming over the Himalayan-Gangetic region and consequent strengthening of the land-sea thermal gradient. This trend is most pronounced in the pre-monsoon season, resulting in a warming of 2.7 C in the 29-year …

A Photochemically Initiated Chemistry For Coupling Underivatized Carbohydrates To Gold Nanoparticles, Xin Wang, Olof Ramström, Mingdi Yan

Chemistry Faculty Publications and Presentations

The sensitive optoelectronic properties of metal nanoparticles make nanoparticle-based materials a powerful tool to study fundamental biorecognition processes. Here we present a new and versatile method for coupling underivatized carbohydrates to gold nanoparticles (Au NPs) via the photochemically induced reaction of perfluorophenylazide (PFPA). A one-pot procedure was developed where Au NPs were synthesized and functionalized with PFPA by a ligand-exchange reaction. Carbohydrates were subsequently immobilized on the NPs by a fast light activation. The coupling reaction was efficient, resulting in high coupling yield as well as high ligand surface coverage. A colorimetric system based on the carbohydrate-modified Au NPs was …

Exploring The Ph Dependence Of Viologen Reduction By Alpha-Carbon Radicals Derived From Hcy And Cys, Dong Wang, William E. Crowe, Robert M. Strongin, Martha Sibrian-Vazquez

Chemistry Faculty Publications and Presentations

The colorimetric reaction of homocysteine (HCy) with a series of viologen salts suggests a linear correlation between the mid-point reduction potential of Hcy-derived α-carbon radicals and pH.