Physical Sciences and Mathematics Commons^™

Refining Molecular Approaches For Bacterial Source Tracking (Bst) In Texas, Joy Truesdale

Open Access Theses & Dissertations

Bacterial source tracking (BST) is a new science that aids in identifying sources of human and animal fecal contamination of environmental water. There are currently two approaches used in BST, library-dependent and library-independent methods. The fecal bacterium E. coli is often used in library dependent methods because it indicates fecal contamination, has been used in human health risk assessments, and has water quality regulatory significance. A disadvantage of E. coli library dependent BST methods is that identification libraries of E. coli isolated from known fecal sources are needed to identify the sources of E. coli isolated from water samples. Further, …

Software Development For A 3d Gravity Inversion And Application To Study Of The Border Ranges Fault System, South-Central Alaska, Rolando Cardenas

Open Access Theses & Dissertations

The Border Ranges Fault System (BRFS) bounds the Cook Inlet and Susitna Basins, and is an important petroleum province within south-central Alaska. A primary goal of our research is to test several plausible models of structure along the BRFS using a novel three-dimensional inversion technique utilizing gravity data, constrained with other geophysical, borehole and surface geological information. This research involves the development of 3D inversion modeling software using C++ Builder from Embarcadero's XE2 Suite. The novel inversion approach directly models known geology with a priori uncertainties assigned to the geologic model to allow researchers to compare alternative interpretations. This technique …

Principal Differential Analysis: Incorporating Covariates Using Kernel Smoothers, Christopher Alfred Dodoo

Open Access Theses & Dissertations

Principal Differential Analysis is a statistical technique which suggests that a given set of functional data curves can be annihilated completely when an estimated linear differential

operator (LDO) is applied (Coddington & Levinson). The novelty of residuals as forcing functions is introduced in PDA.

This thesis builds on PDA with covariates by Jin et al, 2012 by dropping the assumption that the coefficients of the linear differential operator are a product of a function in t and v; the equivalent kernel is used to estimate the coefficient functions at target values. Incorporating covariates with kernel smoothers leads to two …

Functional Data Analysis To Guide A Conditional Likelihood Regression In A Case-Crossover Study Investigating Whether Social Characteristics Modify The Health Effects Of Air Pollution, Juana Maribel Herrera Hernandez

Open Access Theses & Dissertations

In this study we are focused on exploring whether social characteristics modify the relationship between air pollution and hospitalizations due to asthma or chronic pulmonary obstructive disease (COPD) in El Paso, Tx. The case-crossover design with conditional regression analysis was used, here the controls and the case are the same subject at different

times and has the advantage of removing confounding by permanently confounding factors. Social characteristics are included in the models as interactions with the pollutants, variables included are age, sex, ethnicity and insurance status as indicator for the socio-economic status. The pollutant's lags were chosen using the historical …

Changes In Net Ecosystem Production Over The Past 40 Years In Arctic Tundra Ponds Near Barrow, Alaska: Application Of Historic And Modern Techniques, Nickole Ann Miller

Open Access Theses & Dissertations

Arctic environments have gained interest recently due to their sensitivity to climate change. As warming has created longer growing seasons, extended ice-free periods as well as permafrost thaw, the production in freshwater ecosystems has the potential to be greatly impacted. It is hypothesized that as climate change and warming occurs, increases in primary production will occur and ponds will become carbon sinks. Net ecosystem production (NEP) was determined using phytoplankton and periphyton samples collected weekly during the growing season (June - August) from arctic tundra ponds near Barrow, Alaska. Enrichment with 14C was used to determine both weekly photosynthetic rates …

On Different Techniques For The Calculation Of Bouguer Gravity Anomalies For Joint Inversion And Model Fusion Of Geophysical Data In The Rio Grande Rift, Azucena Zamora

Open Access Theses & Dissertations

Density variations in the Earth result from different material properties, which reflect the tectonic processes attributed to a region. Density variations can be identified through measurable material properties, such as seismic velocities, gravity field, magnetic field, etc. Gravity anomaly inversions are particularly sensitive to density variations but suffer from significant non-uniqueness. However, using inverse models with gravity Bouguer anomalies and other geophysical data, we can determine three dimensional structural and geological properties of the given area. We explore different techniques for the calculation of Bouguer gravity anomalies for their use in joint inversion of multiple geophysical data sets and a …

Urban Impact Of Dissolved Metals In The Paso Del Norte Segment Of The Rio Grande, Sumayeh Ahmad Freiwan

Open Access Theses & Dissertations

The Paso del Norte segment of the Rio Grande experiences two seasons per year; the (wet) irrigation season and the (dry) non-irrigation season. The goal of this study was to improve the understanding of occurrence and contribution of dissolved metals in this region during the non-irrigation season. The objectives of this study were to (1) evaluate the impact of anthropogenic sources of metals on the Rio Grande water quality during the non-irrigation season, and (2) estimate the metal loads carried by the flow to the downstream region of El Paso. In order to evaluate the surface water quality of the …

Physical And Sequence Stratigraphy Of The Late Cretaceous Chispa Summit Formation, Jeff Davis County, Texas, Patrick Thomas Dietzel

Open Access Theses & Dissertations

The Late Cretaceous Chispa Summit Formation of west Texas has historically been of interest to the petroleum industry; with new technologies, this old, uneconomical play could prove significant, if not for energy resources, for educational purposes, but little work has been conducted on the formation. The Eagle Ford Formation of southern Texas is time equivalent to the Chispa Summit Formation and is a highly prolific hydrocarbon resource.

Located in western Jeff Davis County, Texas, the Chispa Summit Formation consists of marine shales interbedded with limestone beds and sporadically located siliciclastic beds, measuring a total of 610 m at the type …

Scalar Polarization Operator In A Superfluid Medium, Sajib Kumar Barman

Open Access Theses & Dissertations

A QCD-inspired effective theory of fermions is considered to study superfluidity. We calculate the quark propagator in a theory with fermion-fermion condensate at finite density. In this theory color degrees of freedom are absent and the quark-quark interaction is modeled through a Yukawa interaction term. Since the diquark condensate is neutral, the system is a superfluid. To study the response of this superfluid to the scalar field propagation, we find the scalar polarization operator of the system.

Olivine Ca Content Measured By Icp-Oes To Estimate P-T, Bradley Benavides

Open Access Theses & Dissertations

Ca is a trace element in olivine and its concentration is pressure and temperature dependent, providing a rare opportunity to estimate pressure conditions at which mantle-derived rocks (xenoliths) last equilibrated. This P-T dependence has previously been calibrated for mantle xenoliths, and we applied this technique to samples from Jasper Seamount (Jasper Seamount), an oceanic intraplate volcano (OIV) off the coast of the Baja California Peninsula of Mexico. Preliminary compositions for xenoliths from this location appear to define a magmatic plumbing system that features magma storage near the bottom of the crust. A more detailed analysis of the samples is required …

Determination Of The Effects Of Zno And Ceo2 Nanoparticles In Mesquite (Prosopis Juliflora) And Soybean (Glycine Max): Synchrotron And Spectroscopic Approaches, Jose Angel Hernandez Viezcas

Open Access Theses & Dissertations

The rapid growth of nanotechnology is exposing the environment to abnormal concentrations of engineered nanoparticles (NPs). There is concern about the unknown consequences of NPs on the environment and human health. This Dissertation has relied significantly on Synchrotron and other spectroscopic techniques to give insights on the effects, speciation and distribution of two metal oxide nanoparticles (ZnO, CeO2) on two plant species (Mesquite and Soybean). We evaluated the effects of ZnO (10 nm) and CeO2 (8 nm) NPs on a plant species native to the semi-arid regions of North America, Mesquite (Prosopis juliflora velutina). Mesquite plants grown in hydroponic culture …

Structural, Optical And Electrical Properties Of Yttrium-Doped Hafnium Oxide Nanocrystalline Thin Films, Abhilash Kongu

Open Access Theses & Dissertations

Hafnium oxide (HfO2) has emerged as the most promising high-k dielectric for Metal-Oxide-Semiconductor (MOS) devices and has been highlighted as the most suitable dielectric materials to replace silicon oxide because of its comprehensive performance. In the present research, yttrium-doped HfO2 (YDH) thin films were fabricated using RF magnetron sputter deposition onto Si (100) and quartz with a variable thickness. Cross-sectional scanning electron microscopy coupled with Filmetrics revealed that film thickness values range from 700 A° to 7500 A°. Electrical properties such as AC Resistivity and current-voltage (I-V) characteristics of YDH films were studied. YDH films that were relatively thin (<1500 A°) crystallized in monoclinic phase while thicker films crystallized in cubic phase. The band gap (Eg) of the films was calculated from the optical measurements. The band gap was found to be ∼5.60 eV for monoclinic while it is ∼6.05 eV for cubic phase of YDH films. Frequency dependence of the electrical resistivity (ρac) and the total conductivity of the films were measured. Resistivity decreased (by three orders of magnitude) with increasing frequency from 100 Hz to 1 MHz, attributed due to the hopping mechanism in YDH films. Whereas, while ρac∼1Ω-m at low frequencies (100 Hz), it decreased to ∼ 104 Ω-cm at higher frequencies (1 MHz). Aluminum (Al) metal electrodes were deposited to fabricate a thin film capacitor with YDH layer as dielectric film thereby employing Al-YDH-Si capacitor structure. The results indicate that the capacitance of the films decrease with increasing film thickness. A detailed analysis of the electrical characteristics of YDH films is presented.

Toward New Data And Information Management Solutions For Data-Intensive Ecological Research, Christine Marie Laney

Open Access Theses & Dissertations

Ecosystem health is deteriorating in many parts of the world due to direct and indirect anthropogenic pressures. Generating accurate, useful, and impactful models of past, current, and future states of ecosystem structure and function is a complex endeavor that often requires vast amounts of data from multiple sources and knowledge from collaborating researchers. Ecological data collection has improved rapidly over the past few decades due to the development, innovation, and large scale deployment of automated sensors, which are capable of measuring a gamut of ecosystem properties over broad spatiotemporal scales. Although complex ecosystem models and analyses are increasingly parameterized with …

Estimating Variations In Locking Depth For The Mojave Segment Of The San Andreas Fault Over The Past 1500 Years From Paleoseismic Stress Drop, Teira Solis

Open Access Theses & Dissertations

The most fundamental model for characterizing earthquake occurrence [Reid, 1910] assumes a constant stress accumulation rate on a locked fault segment, which eventually fails at a threshold stress level. While this model provides a conceptual framework for investigating the conditions that prepare a fault for failure, there is little evidence that faults rupture periodically or at a uniform threshold stress. Moreover, this model fails to explain the large differences in earthquake recurrence intervals and paleoseismic slip for segments of major fault systems: why do some faults rupture on the order of 10's of years, while others require 100's of years …

Automatic Elucidation Of Gpi Molecular Structures With Grid Computing Technology, Juan Clemente Aguilar Bonavides

Open Access Theses & Dissertations

Glycosylphosphatidylinositol (GPI)-anchored proteins are involved in many biological processes and are of medical importance. The identification and analysis of the entire collection of free and protein-linked GPIs within an organism (i.e., GPIomics) requires highly sensitive instruments. At present, liquid chromatography-tandem mass spectrometry (LC-MS/MS or -MSⁿ) is the most efficient laboratory technique for these tasks. As a typical MSⁿ experiment produces hundreds of thousands of spectra, the data analysis creates a major bottleneck in high-throughput GPIomic projects. Yet, no computational tool for characterizing the chemical structures of GPI is available to date. We propose a library-search algorithm to …

A Systematic Approach To Manage Missing Data In Pavement Management Systems, Mazin M. Al-Zou'bi

Open Access Theses & Dissertations

Pavements are an important part of the highway transportation infrastructure, accounting for the largest share of the overall investment. A tremendous amount of time and money is spent each year on the construction of new pavements, as well as on the maintenance and rehabilitation of existing pavements.

Transportation agencies use pavement management systems (PMS) for their maintenance and rehabilitation planning, programming, and budgeting. PMS are used to make decisions regarding when maintenance and rehabilitation should be applied. The systems also select what type of treatment should be applied for each pavement section in the network with clear estimations of the …

Improved Efficiency Of Rna Secondary Structure Prediction Using Distributed Computing, Gerardo A. Cardenas

Open Access Theses & Dissertations

The rapidly growing amounts of available biomolecular sequence data, which may represent information from small gene fragments to large complete genomes, have led to the a great need for powerful computational resources for data analysis and storage. With the decoding of the human and other genomes, RNA secondary structure prediction has become an important area of interest in biology and medicine because they help in understanding the mechanisms of many biological processes such as gene regulation and viral replication, and in designing RNA-based therapies to treat various diseases. Due to the complexity of their algorithms, many existing and upcoming computational …

A Declarative Domain Independent Approach For Querying And Generating Visualizations, Nicholas Ricky Del Rio

Open Access Theses & Dissertations

Constructing visualizations using modular visualization environments (MVEs) requires knowledge about visualization transformation theory as well as implementation specific details about how to programmatically chain together relevant sets of modules into pipe and filter-like architectures known as pipelines. Constructing visualization pipelines introduces a number of challenges including: understanding how to transform raw data into forms that can be ingested by MVEs, identifying target modules that map data into graphical data, and understanding how to further transform resulting graphical data into forms that can be presented. Users typically must immerse themselves in a deluge of documentation and usage examples before becoming proficient …

Deprivation And Hispanic Health Paradox: Neighborhood Effects On Children's Wheezing In El Paso, Texas, Young-An Kim

Open Access Theses & Dissertations

This study examines the impact of hypothetical health determinants - including objective and relative economic deprivation, as well as foreign-born composition -at the neighborhood-level on respiratory wheezing among Hispanic children in El Paso, Texas while accounting for individual-level covariates based on hierarchical logistic modeling (HLM). Due to El Paso's majority Latino/a population, focus is placed on the so-called "Hispanic health paradox" through analysis of the impact of neighborhood foreign-born composition on Hispanic children's wheezing. Neighborhood-level variables at the census tract-level are derived from US Census data. The percent of families in poverty and the GINI coefficient for income (income inequality) …

Strong Coupled Quark Matter And Drawbacks Of Its Bcs-Bec Crossover, Israel Portillo Vazquez

Open Access Theses & Dissertations

It was found many years ago, that the ground state wave functions of the Bardeen-Cooper-Schrieer (BCS) superconductivity in a degenerate Fermi gas and the Bose-Einstein condensation (BEC) of composite molecules are essentially the same, and those two states can be smoothly connected through a crossover. This BCS-BEC crossover has being recently extended to relativistic Fermi System. This thesis is dedicated to exploring the possible crossover from BEC to BCS phase on strong-interacting matter and its implications for the system Equation of State. The study will be concentrated on dierent phases of dense quark-matter for vanishing temperatures and densities beyond hadronic …

Utilizing Cyber Espionage To Combat Terrorism, Gary Adkins

Open Access Theses & Dissertations

The world has effectively exited the Industrial Age and is firmly planted in the Information Age. Global communication at the speed of light has been a great asset to both businesses and private citizens. However, there is a dark side to the age we live in, where terrorist groups are able to communicate, plan, fund, recruit, and spread their message to the world. The relative anonymity the internet provides hinders law enforcement and security agencies in not only locating would-be terrorists but also in disrupting their operations. The internet is a loosely knit group of computers and routers and is …

Upgrades To Nrlmol Code, Luis Basurto

Open Access Theses & Dissertations

This project consists of performing upgrades to the massively parallel NRLMOL electronic structure code in order to enhance its performance by increasing its flexibility by: a) Utilizing dynamically allocated arrays, b) Executing in a parallel environment sections of the program that were previously executed in a serial mode, c) Exploring simultaneous concurrent executions of the program through the use of an already existing MPI environment; thus enabling the simulation of larger systems than it is currently capable of performing. Also developed was a graphical user interface that will allow less experienced users to start performing electronic structure calculations by aiding …

Post-Pareto Optimality Methods For The Analysis Of Large Pareto Sets In Multi-Objective Optimization, Victor Manuel Carrillo

Open Access Theses & Dissertations

Multiple objective optimization involves the simultaneous optimization of more than one, possibly conflicting, objectives. Multiple objective optimization problems arise in a variety of real-world applications. In general, the main difference between single and multi-objective optimization is that in multi-objective optimization there is usually no single optimal solution, but a set of equally good alternatives with different trade-offs, also known as Pareto-optimal solutions. There are two general approaches to solve multiple objective optimization problems: mathematical methods and meta-heuristic methods. The first approach involves the aggregation of the attributes into a linear combination of the objective functions, also known as scalarization. The …

An Evaluation Of The Cerro Process As An Efficient Ro Concentrate Management System, Guillermo Guadalupe Delgado

Open Access Theses & Dissertations

The Concentrate Enhanced Recovery Reverse Osmosis (CERRO) Process is a new method to treat RO concentrate and brackish water with high concentrations of silica and calcium sulfate. Prior investigations have shown that the CERRO process can treat this kind of water without fouling or scaling the membranes, but the main factors that allow the system to operate in such conditions were not studied. The research presented here is an evaluation of the CERRO process as an efficient RO concentrate management system. The parameters of operation of the system were evaluated and improved. The precipitation of calcium sulfate was identified as …

Assessing The Equity Implications Of Greenspace Distribution In An Arid Region, Abdelatif Eldeb

Open Access Theses & Dissertations

In the last few decades, vegetation deterioration is receiving increased attention because of its adverse impacts on societal and human health, environmental sustainability, and quality of life. I have selected two cities in Chihuahua Desert region (El Paso and Juarez) as case study sites to develop a novel and applicable methodology for integrating remotely sensed data of different spectral and spatial resolutions into an analysis of the spatial distribution of an urban amenity. The primary objective of this research is to determine if the spatial distribution of greenspace in 2010 is equitable with respect to socio-demographics in El Paso and …

A Semantic Web-Based Methodology For Describing Scientific Research Efforts, Aida Gandara

Open Access Theses & Dissertations

Scientists produce research resources that are useful to future research and innovative efforts. In a typical scientific scenario, the results created by a collaborative team often include numerous artifacts, observations and relationships relevant to research findings, such as programs that generate data, parameters that impact outputs, workflows that describe processes, and publications, posters and presentations that explain results and findings. Scientists have options in what results to share and how to share them, however, there is no systematic approach to documenting scientific research and sharing it on the Web.

The goal of this research is to define a systematic approach …

Lead And Associated Heavy Metal Distribution In Ciudad Juarez, Mexico, Samia Elfituri Grimida

Open Access Theses & Dissertations

Concern over the extent and sources of heavy metals exposure has arisen worldwide since their significant effects have been discovered in the environment. There is general agreement that research is needed to examine the residual lead and its association to heavy metals contamination in soil and quantify the health hazards. This research was directed to quantify and document the geographic distribution of lead and associated heavy metals concentration in Ciudad Juarez, Mexico. Lead, cadmium, chromium, zinc, and copper were selected to analysis. The soil samples used in this research were collected during a previous Encountors Binational Community Lead Study (RO1ES …

Multiplicity Adjustments For Respecification Searches In Structural Equation Models, John Appiah Kubi

Open Access Theses & Dissertations

Structural Equation Modeling (SEM), as a statistical modeling technique, is one of the most comprehensive and flexible approaches to data analysis currently available. Its use has been increasing steadily over the past few decades. Generally, it refers to a family of

techniques that employs the analysis of covariance to establish relationships among a set of variables. It allows researchers (or users) to assess the adequacy of their hypothesized models with their sample data. Often times, in assessing their models, researchers are not

only interested in the overall fit of their model but they are also interested in knowing which proposed …

Comparison Of Bayesian Nonparametric Density Estimation Methods, Adel Bedoui

Open Access Theses & Dissertations

Density estimation has a long history in statistics. There are two main approaches to density, estimation parametric and nonparametric. The first approach requires specification of a family of densities f and estimation of the unknown parameter $\theta$ using a suitable estimation method, for example, maximum likelihood estimation. This approach may be prone to bias that arises from either estimation of the parameter or from incorrect specification of the probability distribution. The second approach, does not assume a specific parametric family.

In this thesis, we implement three density estimation methods that use Bayesian nonparametric approaches utilizing Markov Chain Monte Carlo methods. …

Investigation Of The Radiative Heat Release Factor Of Premixed Oxy-Syngas Flames, Martin De La Torre

Open Access Theses & Dissertations

A significant part of the United States is being powered by combustion devises relying on coal since it is abundant and is a high emitting source of electricity per unit energy, however; the burning of this fuel is responsible for a significant contribution for the pollutant emissions causing global warming. Because coal is one of the main sources of energy in the U.S. and around the globe, the scientific community has been investigating ways to meet current and future governmental emission requirements. It is now well established that radiating heat from the flame is a major contributor of the heat …