Physical Sciences and Mathematics Commons^™

A Retrospective Study Of Dust Storms And Respiratory Hospitalizations In El Paso, Texas Using A Case-Crossover Study Design, Yanlei Peng

Open Access Theses & Dissertations

Dust storms frequently occur in El Paso, Texas, but little is known about their respiratory health effects. The association between dust storm and hospitalization for respiratory illness will be studied through a case-crossover study design. The goal is to ascertain the effect of dust storms, adjusted for weather and other pollutants, and to explore the potential harmfulness for different subgroups of residents. A case-crossover study allows patients to serve as their own controls, in order to reduce confounding. The history, relationship, and application of the case-control and case-crossover study designs are reviewed in this thesis. The estimating equations for conditional …

Computational Modeling Studies Of The Structures And Properties Of Organotin(Iv) And Stannyl-Thioether Systems With Comparisons To X-Ray Crystallography, Michelle R. Stem Joseph

Open Access Theses & Dissertations

Controlling the toxic effects of organotin(IV) compounds involves engineering the structure of the molecules to optimize their properties. Molecular engineering, coupled with improved capabilities to generate reliable computational optimization models (COMs), will enable researchers to have greater success at harnessing the highly specific cytotoxicity of organotins. For example, as the thio_n ligand phenyl groups were replaced with Cl atoms, the S-Sn intramolecularity was strengthened, the bond distance decreased, and the stannyl tetrahedral structure was deformed from its triphenyl conformation. With each substitution, conformation deformations lowered the damaging bioactivity levels of thio_n. Bonding various ligands to organotin(IV) compounds …

Multiplicative Riesz Decomposition On The Ring Of Matrices Over A Totally Ordered Field, Julio Cesar Urenda

Open Access Theses & Dissertations

The Riesz Decomposition Theorem for lattice ordered groups asserts that when G is an l-group and when a nonnegative element a is bounded by a product of nonnegative elements b1,...,bn, then a can be decomposed into a product of nonnegative elements b'1,...,b'n, i.e., a = b'1·...·b' n, with the property that b'i ≤ bi for any i = 1,...,n. In this work we characterize all nonnegative matrices for which this decomposition is possible with respect to matrix multiplication. In addition, we show that this result can be applied to ordered semigroups.

Experimental Study Of The Response Of Semiconductor Detectors For Edxrf Analysis., Sunil Kumar Valaparla

Open Access Theses & Dissertations

This present work relates to the study and characterization of the response function of an energy-dispersive x-ray spectrometer. The problems of energy, efficiency and resolution calibration of the system operating in the energy (5-60 keV) range are discussed. We present the operation characteristics of the portable pyro-electric x-ray generator (COOL-X) and the application of the calibrated response spectrum in the elemental analysis using X-ray Fluorescence (XRF).

We study the response of the Si(Li)-Pin XR-100CR semiconductor detector to low energy photons. The photopeak efficiency was determined experimentally by using radioisotopes and compared against a theoretical efficiency curve. The efficiency for gamma …

Using Chromium Stable Isotopes To Monitor Chromium Reactive Transport: Oxidation Experiments And Field Studies, Alejandro Villalobos Aragon

Open Access Theses & Dissertations

Chromium (Cr) is a common contaminant found at a number of sites globally. Cr sources can be either anthropogenic or natural. Cr occurs in nature in two valences, with Cr(VI) being carcinogenic, more toxic and mobile than Cr(III). Reduction of Cr(VI) to Cr(III) is a common remediation strategy, but monitoring Cr reduction using only concentration and speciation analyses is a difficult endeavor because concentrations can be affected by dilution and advection in addition to reduction. Cr isotopes are fractionated during reduction processes, so monitoring isotopic changes in Cr may be a faster and more effective way to monitor reduction. This …

By-Product Synergy In The Textile Industry: Indigo Waste Recovery In The Denim Finishing Process, Dennis Wambuguh

Open Access Theses & Dissertations

Textile dyeing effluents present a substantial environmental problem, primarily because such effluents contain high concentrations of waste dyes, dye-products, and variable salts. The stonewashing process for the degradation of blue indigo to create a `faded' look in blue denim results in high concentrations of indigo dye waste in the resulting effluent and because indigo is very difficult to decompose biologically, the effluent ends up in the environment, raising aesthetic concerns and damaging the integrity of the rceiving streams. Wastewater containing indigo is characterized by a moderate amount of chemical oxygen demand (COD), pH, suspended solids, dissolved solids and a dark …

Silica Removal From Brine By Using Ion Exchange, Carlos R. Acevedo

Open Access Theses & Dissertations

Local governments have been forced to look for additional water sources to satisfy the ever increasing demand for fresh water. Very often, the new water sources such as the underground water in continental territories have high salt content. Currently, reverse osmosis technology (RO) is one of the most common processes for water desalination. However, this process is limited by high silica and salt concentrations in water. At high concentrations silica clogs the membranes used in the RO process, reducing their life and increasing operational costs. In this study, quaternary ammonium resins and sulfonic acid resins were used to remove silica …

Multi-Objective Network Reliability Optimization Using Evolutionary Algorithms, Franciso Oswaldo Aguirre

Open Access Theses & Dissertations

This work presents a new multiple objective evolutionary algorithm to solve three well known network reliability allocation problems considering different conflicting objectives to be optimized simultaneously. The new algorithm is applied in the design of a telecommunication network that is formed for several stations or nodes interconnected by telecommunication links or paths. The problem presented in this work involves finding which links to activate in order to obtain connectivity in the nodes. The number of nodes that need to be connected depends of the case that is being evaluated. The three network reliability problems considered are: all-terminal, k-terminal, and two-terminal. …

Supporting Novice Application Users In Learning By Trial And Error And Using Help, Oscar Daniel Andrade

Open Access Theses & Dissertations

This thesis examines three related topics in analyzing user preferences for troubleshooting application usability problems and the kinds of issues that influence such preferences. The goal of this thesis is to propose (1) ways in which users can be supported to learn to use applications and (2) a model to rewrite help such that users are able to adapt its contents dynamically.

The consensus of documentation research is that users rarely use help, usually preferring to muddle through. To increase use of help, tutorials for novice users could be changed from guided presentations toward using the application's help system. To …

Symbiotic Effects Of The Fungus Glomus Sp. On Chromium(Iii), Chromium(Vi), And Lead(Ii) Uptake By Mesquite (Prosopis Sp.): A Novel Method To Remediate Heavy Metals, Jack A. Arias

Open Access Theses & Dissertations

The indiscriminate disposal of lead (Pb) and chromium (Cr) containing wastes has resulted in a detrimental impact on environmental health. Lead and Cr are in the EPA priority list due to their degree of toxicity on humans, animals, plants, and other living organisms. The removal of toxic wastes involves technologies that are expensive, sometimes incomplete, and could represent health hazards. In addition, site restoration after contaminant removal encompasses time and technological resources. Phytoremediation, the use of plants alone or associated with microorganisms, represents a potentially cost-effective option in the long term management of contaminated sites. Various plants known as "hyperaccumulators" …

Salsola Kali (Tumbleweed): A Possible Biomonitoring Device For The Detection Of Airborne Heavy Metals, Tenoch Benitez

Open Access Theses & Dissertations

Vehicular congestion generates particulate matter and contaminants such as lead, cadmium, copper, chromium, nickel, and zinc which have been detected in the U.S.-Mexico border region. To overcome the inconvenience of expensive sampling techniques, scientists started to assess air quality by using bioindicator plants, a technique called biomonitoring. Biomonitoring is an inexpensive and environmentally friendly approach to determine inorganic contaminants at trace levels. The purpose of this project was to determine the effectiveness of tumbleweed (Salsola kali) plants, sprayed with chelating agents, as a passive monitoring device to determine the possible presence of heavy metals in the ambient air around international …

Third Grade Students' Challenges And Strategies To Solving Mathematical Word Problems, Elizabeth Bernadette

Open Access Theses & Dissertations

This project explores the difficulties and challenges that third grade students face solving mathematical word problems. Three students were asked to be participants and share their knowledge on this topic as well as their work. After extensive interviews it was concluded that the challenges of mathematical word problems include but are not limited to the level of reading comprehension, conceptual understanding of mathematical concepts, and the belief that math is a compilation of computations and unexplainable procedures. The participants provided insight as to what strategies are helpful to students. These strategies include group discussion on problem solving strategies, self-assessment, incorporating …

Uptake Of Pahs And Metals By Plants In Arid Environment, Zarhelia Carlo

Open Access Theses & Dissertations

Study of plant uptake of PAHs with the concurrent presence of metals in laboratory conditions was done with the aim to resemble specific combinations of natural environment. Toxicological response of seedlings was tested to define treatment conditions or possible interferences. The levels of PAHs and metals in the treatments were set up to have no toxic effect on plant growth. The complexity of concurrent contamination was demonstrated in a laboratory with soil. No visual differences were observed among various dose treatments of Cu and Zn with organics three PAHs, Phenanthrene (Phen), Acetoanthrancene, and Benzo(a)pyrene (BaP). The metal analysis by ICP/OES …

Real-Time Image-Based Motion Detection Using Color And Structure, Manali Chakraborty

Open Access Theses & Dissertations

Motion detection is an important problem in computer vision and has multiple applications in the real world, including surveillance-related activities, gaming, and human-robot interactions. These systems need to be robust enough to handle fluctuations in light intensity and other external factors like noise and compression artifacts. In this thesis a method is proposed for detecting the regions of motion from a video sequence in real time. The main idea of this work is to detect motion based on both structure and color. Structure-based detection is carried out using information from the Census Transform computed on gradient images obtained with Sobel …

Introduction To Pseudo-Ordered Groups, Maria Dolores Cruz

Open Access Theses & Dissertations

We will give a definition, examples and basic properties of pseudo-ordered groups. These generalize partially-ordered groups. The pseudo-ordered groups have a compatible pseudo-order relation that may lack transitivity. Unlike partially-ordered groups, our groups can be finite and still admit a non-trivial pseudo-order. We will show necessary and sufficient conditions for a group to have a compatible pseudo-order. We also consider maximal pseudo-orders. We give a definition of a pseudo chain induced by a pseudo-order and characterize all pseudo chains on the group $\mathbb {Z}_{n}.$ We will calculate the number of non-isomorphic pseudo-orders on $\mathbb {Z}_{n}$ for $ n < 24.$

Geography Of Pestecide Exposure In The Lower Valley (El Paso County, Texas), Critina Solis Sanchez

Open Access Theses & Dissertations

Previous studies using GIS have been used to understand the demographics of particular areas of a city and the risks associated with living there. In the Lower Valley (Socorro, Clint, and San Elizario) area of El Paso County (TX), there has been a rapid growth in population. This increase in growth has led to this project about the types of pesticides used in farms and if they are creating possible health risks for people living in this area and which populations are most at risk. To determine population risk, I use existing GIS information, specifically a USDA aerial photograph taken …

Survey Research On Communication And Language For English Language Learners And Native English Speakers Enrolled In A College Course On Statistical Literacy, Maria Guadalupe Valenzuela

Open Access Theses & Dissertations

The purpose of this study was to examine in what ways language is a factor that affects the learning process of students in an introductory statistics class. This research used a questionnaire survey instrument called: CLASS, Communication, Language And Statistics Survey that was applied to a total of 137 college students from a large southwestern public university, 83 of these students were self-identified as native English speakers (NOELL) and 53 were self-identified as English learner speakers (ELL) and one was dropped. This research found that in statistical instruction, there are some particular differences in behavior and learning process in the …

In-Vivo Delivery Of Dna Vaccines Using Metallo-Lipid Nanoparticles, Clarissa Sara Gomez

Open Access Theses & Dissertations

There has been a rapidly growing area of research in the design and synthesis of molecules that self-organize in water to form functional nanosystems and due to the high interest in the area metal ligand complexes were tested as drug delivery systems with a Leishmania vaccine. Herein, we present the design, synthesis and functional activity of Cu(II) and Zn(II) complexes that self-assemble in water to form spherical nanoscale structures that exhibit an affinity to bind DNA and deliver it into eukaryotic cells with a high percent efficiency in-vitro. In order to assess the effectiveness of these nanoparticles to deliver DNA …

Adaptive Hp-Fem For Elliptic Problems In 3d On Irregular Meshes, David Andrs

Open Access Theses & Dissertations

This work deals with adaptive hp-FEM on irregular meshes. It shows the advantage of completely irregular meshes, using the arbitrary level hanging nodes. The above is demonstrated on a numerical example with distribution of electrical potencial.

Optical And Vibrational Spectroscopic Studies Of Synthetic Maya Pigments As A Function Of, Swati Kumar

Open Access Theses & Dissertations

Pigments developed by the Mayan civilization around 8th century, represent some of the most versatile pigments known to date. Several derivatives of these pigments are popular subjects of current research interest. This is due to the characteristic stability which is provided by a bonding mechanism between the dye and the clay. One such pigment "Maya Blue", a mixture of Indigo and Palygorskite, provides a dramatic background for murals and ceramics throughout Mesoamerica. Several research groups have devoted time and interest in unlocking its particular features.1-3

The work embodied in this Thesis is focused on the synThesis and characterization of three …

A Study Of The Interaction Of Thioindigo Dye, With Several Inorganic Host Materials, Alejandra Ramirez

Open Access Theses & Dissertations

Maya Blue has been the focus of numerous studies and is believed to be a mixture of palygorskite clay and indigo dye.^1,2 Several derivatives of this pigment have been developed with intriguing properties. For instance, the dye thioindigo reacts with the palygorskite clay to exhibit a broad range of colors from red to blue under UV-Vis excitation. Based on FT-Raman and computer simulation, previous work performed in our group could relate indigo and thioindigo interaction to the aluminum sites in the framework. super>3,4

The work performed with other inorganic host materials such as, layer structures and zeolites have …

Study Of Structural And Spectroscopic Properties Of Small Zns Clusters By Dft, Venkata Ramana Chaganti

Open Access Theses & Dissertations

ABSTRACT

The small clusters (aggregates of atoms containing a few tens of atoms) of semiconductors and metals often adopt very different shapes than the fragments of these materials in the bulk phase. Due to their large surface to volume ratio and unsaturated bonds, the small clusters often have properties that are very different from their bulk. Semiconductor clusters are extensively studied for their potential applications in a wide variety of systems from opto-electronic devices to spintronics. The present work is devoted to understanding the structural and electronic properties of small clusters of the zinc sulfide ZnnSn where n = 1 …

A Distributed Reconstruction Of Ekg Signals, Gabriel Cordova

Open Access Theses & Dissertations

In this Thesis the parallel computing methodology is applied to an algorithm used in the reconstruction of electrocardiographic (EKG) measurements. The reconstructions are being performed to obtain a better understanding of the source and behavior of the electrical activity that generates the EKG measurements. The contribution of this Thesis is to identify and eliminate inefficiencies present in the current reconstruction algorithm. Additionally, this Thesis reduces the computation times of the EKG reconstruction by applying distributed computing through the use of Remote Procedure Calls (RPC). Lastly, it provides an analysis of the speed-up and efficiency of the distribution implemented using parallel …

Evaluation Of An Image Processing Algorithm For Scene Change Detection, Daniel Flores

Open Access Theses & Dissertations

Despite the efforts to reduce traffic accidents by government entities and automobile manufactures, the numbers of accidents are not considerably reduced. An evaluation of an algorithm based on the fly's eye is done on this research applying its principles to detect scene change on images for printed circuit boards providing initial steps to implement this algorithm on vehicular traffic to keep track of objects moving on the field for collision avoidance purposes. The effectiveness of the algorithm is addressed through a comparison of its performance with that found in experimental data.

Screening The Phytoremediation Potential Of Native Plants Growing On Mine Tailings In Arizona, Usa, Md Nazmul Haque

Open Access Theses & Dissertations

Mining companies have been playing an important role for the utilization of the Earth's natural resources for the prosperity of human society. However, the mining of resources has generated solid wastes called tailings that have become a serious environmental threat worldwide. Technologies such as soil caping have been used to remediate the problem. Nevertheless, the remediation of mine tailings using conventional technologies is costly and environmentally unpleasant. Since the last few decades, a plant based technology known as phytoremediation has appeared as a promising alternative. Several plant species have demonstrated to have phytoremediation capabilities; though, best results have been obtained …

A Multi-Tracer Study Of Saltwater Origin, Cross-Formational Flow, And The Geochemical Evolution Of Groundwater In The Southern High Plains Aquifer Along The Western Caprock Escarpment, East-Central New Mexico, Jeff Langman

Open Access Theses & Dissertations

Sustainable management of groundwater resources requires sufficient knowledge of the distribution of fresh and saline groundwater and the processes affecting saltwater intrusion that may influence the beneficial use of groundwater. A hydrogeologic investigation that coupled various chemical and isotopic tracers, including 3H/3He, 14C, δD, δ18O, 87Sr/86Sr, and δ11B, with the physical characteristics of the aquifer was conducted to determine source waters, the origin of saltwater and its influence through cross-formational flow, and water-rock interactions in the Southern High Plains aquifer along the Western Caprock Escarpment. Sub-aquifers or local flow systems are present along the Western Caprock Escarpment, and the study …

Integrated Geophysical Data Processing And Interpretation Of Crustal Structure In Ethiopia With Emphasis On The Ogaden Basin And Adjacent Areas, Ketsela Tadesse

Open Access Theses & Dissertations

The combined effects of magmatism and stretching due to asthenosphere upwelling modifies the crustal structure of the Earth as seen in the Ethiopian rift and adjacent areas. The Ethiopian rift provides unique opportunities to understand the nature of rifted crust and the intensity of its modification by magmatic processes. I used geological and geophysical data to conduct an integrated study in and around the Ethiopian rift including the northern Kenyan rift and the northern part of the Kenyan dome. New gravity, controlled source seismic, and teleseismic data from the EAGLE (Ethiopia-Afar Geoscientific Lithospheric Experiment) were used as additional constraints in …

On Markov Chain Monte Carlo Methods For Neural Networks, Raul Cruz-Cano

Open Access Theses & Dissertations

Neural Networks (NN) have been used successfully to solve many different problems. It is an area of computer science and statistics that is very useful in real life. The advantages of NN consist of their ability to produce nonlinear input-output mapping, their adaptability, fault tolerance, uniform analysis and design. The search for better ways to train them consists of trying to find the optimal values of their free parameters. Some of these training algorithms are based on Markov Chains. They have some advantages over the traditionally used deterministic methods. In this document the main ideas related to these concepts are …

Lithospheric Structure Of The Basin And Range Province-Southwestern Colorado Plateau. Southeastern California, Southern Nevada, And Western Arizona, Nigel Oakley Hicks

Open Access Theses & Dissertations

The Basin and Range Province of the western United States is an unusually wide continental rift zone and its structure and evolution have been the topic of much debate. Active source seismic surveys within the Basin and Range Province have delineated a relatively uniform crustal thickness (-30 km) despite varying magnitudes of crustal extension (<10-300 km). Large scale Cenozoic crustal extension has exhumed midcrustal rocks (from 10-20 km depth) along low angle detachment faults to create metamorphic core complexes (exposed lower plate rocks). In contrast to the extreme amounts of extension and internal deformation of the Basin and Range, the Colorado Plateau has remained a relatively rigid block, with a crustal thickness of 40-50 km, apparently resistant to the deformation processes that have shaped the Basin and Range observed today. In general, geophysical surveys reveal a significant contrast in crustal structure between the Basin and Range and it's transition into the Colorado Plateau.

The debate about the origin of the Basin and Range has underscored the need for additional geophysical constraints. Thus in this study, a regional analysis of lithospheric structure in the region of southeastern California, southern Nevada, and western Arizona that includes the Basin and Rangesouthwestern …

Evolution Of Quaternary Intraplate Mafic Lavas Detailed Using Helium-3 Surface Exposure And Argon-40/Argon-39 Dating, And Elemental And Helium, Strontium, Neodymium And Lead Isotopic Signatures: Potrillo Volcanic Field, New Mexico, United States Of America And San Quintin Volcanic Field, Baja California Norte, Mexico, Wendi Joan Whitehead Williams

Open Access Theses & Dissertations

The Pleistocene Potrillo volcanic field (PVF) resides within the southern axis of the Rio Grande Rift, New Mexico, U.S.A., near the eastern extent of the Basin and Range Province. Its alkalic mafic volcanism has resulted in several hundred cones, flows and maars distributed over approximately 4,600 km2. Alignments are segregated into two halves relative to the East Robledo fault system that dissects this field. Three of the five maars have brought peridotitic and lower to upper crustal xenoliths to the surface; several older, non maar-related flows from the west half of the field host ultramafic clots. Stratigraphic relationships, 3He surface …