Physical Sciences and Mathematics Commons^™

Mechanistic Studies Of The Iron And Molybdenum Nitrogenases, Derek Harris

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As a basic building block in many biological molecules the element nitrogen (N) is essential for life. Dinitrogen (N2) is abundant in Earth’s atmosphere, but this form is biologically unavailable. To be biologically available N2 must undergo an energy demanding reduction reaction to the fixed form, ammonia (NH3). The industrial Haber-Bosch process, which accounts for approximately 50% of the worlds fixed nitrogen, uses energy from fossil fuels to achieve high pressures and temperatures to facilitate the reaction. The energy used by Haber-Bosch accounts for approximately 2% of the world’s annual supply. The remainder of fixed nitrogen is produced biologically by …

Geological Characterization Of Precambrian Nonconformities: Implications For Injection-Induced Seismicity In The Midcontinent United States, Laura Cuccio

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The midcontinent United States, a region which typically does not experience many earthquakes, has experienced a significant increase in the number of earthquakes over the last decade. This increase in earthquake activity has been linked to wastewater injection, a process in which large volumes of wastewater from oil and gas extraction are injected into deep (2-3 km), high-permeability sedimentary rocks, near low-permeability Precambrian (>540-million-year-old) crystalline ‘basement’ rocks. The contact between these two rock types is referred to as the Precambrian nonconformity. Injection-induced earthquakes occur on or near basement-hosted faults due to an increase in pore fluid pressures, which implies …

Exact Approaches For Bias Detection And Avoidance With Small, Sparse, Or Correlated Categorical Data, Sarah E. Schwartz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Every day, traditional statistical methodology are used world wide to study a variety of topics and provides insight regarding countless subjects. Each technique is based on a distinct set of assumptions to ensure valid results. Additionally, many statistical approaches rely on large sample behavior and may collapse or degenerate in the presence of small, spare, or correlated data. This dissertation details several advancements to detect these conditions, avoid their consequences, and analyze data in a different way to yield trustworthy results.

One of the most commonly used modeling techniques for outcomes with only two possible categorical values (eg. live/die, pass/fail, …

Optimizing Barrier Removal To Restore Connectivity In Utah’S Weber Basin, Maggi Kraft

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

River barriers, such as dams, culverts and diversions are important for water conveyance, but disrupt river ecosystems and hydrologic processes. River barrier removal is increasingly used to restore and improve river habitat and connectivity. Most past barrier removal projects prioritized individual barriers using score-and-rank techniques, neglecting the spatial structure and cumulative change from multiple barrier removals. Similarly, most water demand models satisfy human water uses or, only prioritize aquatic habitat, failing to include both human and environmental water use benefits. In this study, a dual objective optimization model identified in-stream barriers that impede quality-weighted aquatic habitat connectivity for Bonneville cutthroat …

Twentieth Century Channel Change Of The Green River In Canyonlands National Park, Utah, Alexander E. Walker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Since the early 20^th century, river channels of the Colorado River basin have narrowed, decreasing available riparian and aquatic habitat. Changes are considered to be the result of three major factors: wide-spread water development, increasing hydroclimate variability and the invasion of non-native tamarisk (Tamarix spp.), altering flow regime and sediment supply. Different studies have reached different conclusions about the relative roles of flow regime, sediment supply and tamarisk in causing narrowing.

I investigated channel change in the lower Green River within Canyonlands National Park to describe channel changes in the 20^th century and understand the roles …

The Investigation Of Gravity Waves In The Mesosphere / Lower Thermosphere And Their Effect On Sporadic Sodium Layer, Xuguang Cai

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Gravity waves in the atmosphere are the waves with gravity and buoyancy force as the restoring forces. Gravity waves will significantly impact the Mesosphere Lower / Thermosphere (MLT), and the breaking of gravity waves is the key factor to cause the cool summer and warm winter in the Mesopause region. Therefore, it is important for us to investigate gravity waves. In this dissertation, we mainly use USU Na lidar data to explore gravity waves in the MLT. The exploration is made up of two projects. One is the investigation of gravity wave breaking and the associated dynamic instability by USU …

Exploring And Describing The Spatial And Temporal Dynamics Of Medusahead In The Channeled Scablands Of Eastern Washington Using Remote Sensing Techniques, Timothy M. Bateman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Medusahead is a harmful weed that is invading public lands in the West. The invasion is a serious concern to the public because it can reduce forage for livestock and wildlife, increase fire frequency, alter important ecosystem cycles (like water), reduce recreational activities, and produce landscapes that are aesthetically unpleasing. Invasions can drive up costs that generally require taxpayer’s dollars. Medusahead seedlings typically spread to new areas by attaching itself to passing objects (e.g. vehicles, animals, clothing) where it can quickly begin to affect plants communities. To be effective, management plans need to be sustainable, informed, and considerate to invasion …

Real Simple Lie Algebras: Cartan Subalgebras, Cayley Transforms, And Classification, Hannah M. Lewis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The differential geometry software package in Maple has the necessary tools and commands to automate the classification process for complex simple Lie algebras. The purpose of this thesis is to write the programs to complete the classification for real simple Lie algebras. This classification is difficult because the Cartan subalgebras are not all conjugate as they are in the complex case. For the process of the real classification, one must first identify a maximally noncompact Cartan subalgebra. The process of the Cayley transform is used to find this specific Cartan subalgebra. This Cartan subalgebra is used to find the simple …

Stream Temperature Monitoring And Modeling To Inform Restoration: A Study Of Thermal Variability In The Western Us, Jessica R. Wood

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Water temperature is an important variable for aquatic ecosystems. Salmonid population numbers and distribution are heavily influenced by stream temperature, and there is growing concern about the health of salmonid populations with anticipated climate change. Managers are looking to efficiently evaluate options to maintain stream temperatures needed by salmonids. This study evaluated and compared stream temperature restoration alternatives in two streams with warm temperatures using stream temperature monitoring and modeling.

The first study identified pockets of cold water that are important to native fish species in Nevada’s Walker River. Comparison of monitoring results with existing basin-scale model outputs identified two …

Usarray Imaging Of North American Continental Crust, Xiaofei Ma

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The layered structure and bulk composition of continental crust contains important clues about its history of mountain-building, about its magmatic evolution, and about dynamical processes that continue to happen now. Geophysical and geological features such as gravity anomalies, surface topography, lithospheric strength and the deformation that drives the earthquake cycle are all directly related to deep crustal chemistry and the movement of materials through the crust that alter that chemistry.

The North American continental crust records billions of years of history of tectonic and dynamical changes. The western U.S. is currently experiencing a diverse array of dynamical processes including modification …

Application Of Machine Learning And Statistical Learning Methods For Prediction In A Large-Scale Vegetation Map, Carla M. Brookey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Original analyses of a large vegetation cover dataset from Roosevelt National Forest in northern Colorado were carried out by Blackard (1998) and Blackard and Dean (1998; 2000). They compared the classification accuracies of linear and quadratic discriminant analysis (LDA and QDA) with artificial neural networks (ANN) and obtained an overall classification accuracy of 70.58% for a tuned ANN compared to 58.38% for LDA and 52.76% for QDA.

Because there has been tremendous development of machine learning classification methods over the last 35 years in both computer science and statistics, as well as substantial improvements in the speed of computer hardware, …

Longitudinal Thermal And Solute Dynamics In Regulated Rivers, Muhammad Rezaul Haider

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Dam releases increase river stage and can reverse groundwater movement into and out of the river. As the flood, thermal, and solute waves travel downstream in a regulated river, the size of the waves is anticipated to be affected both by river processes and exchanges with near river groundwater. This study established a modeling framework to quantify the influences of the groundwater exchanges on the temperatures and solute concentration dynamics along regulated rivers. The wave properties, volume of exchanges, conservative solute mass exchanges, and heat energy exchanges were calculated as a function of time and distance downstream. Results show that …

Approaches, Techniques, And Tools For Identifying Important Code Changes To Help Code Reviewers, Maneesh M. Mohanavilasam

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Software development is a collaborative process where many developers come together and work on a project. To make things easy and manageable, software is developed on a version control system. A version control system is a centralized system which stores code and adds code from all other developers as an increment to the code base in the repository. Since multiple people work on the same code repository together, it is important to make sure that their contributions do not conflict with each other. It is important to maintain the quality and integrity of the repository. This is where the code …

Optimizing Bioengineered Vascular Systems: A Genetic Algorithm Approach, Sima Mehri Kochaki

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Efficiency of current cell cultures producing biological products is limited due to accumulation of the product and waste on the cells. A previous work aims at assisting bioengineers in solving this problem by introducing a new set of cells which possess the ability to connect to one another and thus form a network. Once created, the network of cells can help the initial cellules by removing their waste and product as well as nourishing them. Our project explores a technique to be able to create the best network of such cells; hence maximizing the amount of metabolic product in the …

Extensions And Improvements To Random Forests For Classification, Anna Quach

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The motivation of my dissertation is to improve two weaknesses of Random Forests. One, the failure to detect genetic interactions between two single nucleotide polymorphisms (SNPs) in higher dimensions when the interacting SNPs both have weak main effects and two, the difficulty of interpretation in comparison to parametric methods such as logistic regression, linear discriminant analysis, and linear regression.

We focus on detecting pairwise SNP interactions in genome case-control studies. We determine the best parameter settings to optimize the detection of SNP interactions and improve the efficiency of Random Forests and present an efficient filtering method. The filtering method is …

Novel Statistical Models For Quantitative Shape-Gene Association Selection, Xiaotian Dai

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Other research reported that genetic mechanism plays a major role in the development process of biological shapes. The primary goal of this dissertation is to develop novel statistical models to investigate the quantitative relationships between biological shapes and genetic variants. However, these problems can be extremely challenging to traditional statistical models for a number of reasons: 1) the biological phenotypes cannot be effectively represented by single-valued traits, while traditional regression only handles one dependent variable; 2) in real-life genetic data, the number of candidate genes to be investigated is extremely large, and the signal-to-noise ratio of candidate genes is expected …

Rancher Perceptions Of Ecosystem Services From Rangelands Of The Intermountain West, Elisabeth C. York

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rangelands within the Great Basin are responsible for the provision of multiple resources that humans depend on for a variety of reasons. Ranchers in this region are dependent on public lands to remain economically viable in their cattle operations. As a majority of land in this region is publically owned, there are varying interests at play in what should and could be the focus of management. Ranchers are charged with implementing strategies aimed at conserving these landscapes and their motivations for what to manage may significantly influence resource provision from Intermountain West ecosystem.

In this study, I sought to understand …

Non-Methane Hydrocarbon Source Apportionment And Btex Risk Assessment Of Winter 2015 In Roosevelt, Utah, Jerimiah Lamb

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Non-Methane Hydrocarbons (NMHC) monitored in Roosevelt Utah including Benzene, Toluene, Ethylbenzene and Xylene (collectively known as BTEX) are associated with deleterious effects including cancer. This study was designed to assess the origin and effect of the toxicants and addressed two points: 1) Source identification using the USEPA’s Positive Matrix Factorization (PMF) and NOAA’s Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model and 2) A human health risk assessment based on ambient concentrations of BTEX collected at the Roosevelt site. Model fit indicated that the primary contributor to total NMHCs was local oil and gas operations and was supported by previous …

Extracting And Visualizing Data From Mobile And Static Eye Trackers In R And Matlab, Chunyang Li

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Eye tracking is the process of measuring where people are looking at with an eye tracker device. Eye tracking has been used in many scientific fields, such as education, usability research, sports, psychology, and marketing. Eye tracking data are often obtained from a static eye tracker or are manually extracted from a mobile eye tracker. Visualization usually plays an important role in the analysis of eye tracking data. So far, there existed no software package that contains a whole collection of eye tracking data processing and visualization tools. In this dissertation, we review the eye tracking technology, the eye tracking …

Geometric Facility Location Problems On Uncertain Data, Jingru Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In this dissertation, we study several facility location problems on uncertain data. We mainly consider the k-center problem and many of its variations. These are classical problems in computer science and operations research. These problems on deterministic data have been studied extensively in the literature. We consider them on uncertain data because data in the real world is often associated with uncertainty due to measurement inaccuracy, sampling discrepancy, outdated data sources, resource limitation, etc. Although we focus on the theoretical study, the algorithms developed in this dissertation may find applications in other areas such as data clustering, wireless sensor …

Database Auto Awesome: Enhancing Database-Centric Web Applications Through Informed Code Generation, Jonathan Adams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Database Auto Awesome is an approach to enhancing web applications comprised of forms used to interact with stored information. It was inspired by Google's Auto Awesome tool, which provides automatic enhancements for photos. Database Auto Awesome aims to automatically or semi-automatically provide improvements to an application by expanding the functionality of the application and improving the existing code.

This thesis describes a tool that gathers information from the application and provides details on how the parts of the application work together. This information provides the details necessary to generate new portions of an application.

These enhancements are directed by the …

Estimating Accuracy Of Personal Identifiable Information In Integrated Data Systems, Amani "Mohammad Jum'h" Amin Shatnawi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Both government agencies and private companies rely on the collection of personal data on an ever-increasing scale. Out of necessity, person data include Personal Identifiable Information (PII), which is information that could potentially identify a specific individual. Many of these data would be integrated, so data analyst, policy makers or corporate officers can use it to make decisions or get a conclusion. Integrating data in a heterogeneous database environment create a need to estimate the accuracy of that data; without a valid assessment of accuracy there is a risk of coming with incorrect conclusions or making bad decision based on …

A Comparison Of Five Statistical Methods For Predicting Stream Temperature Across Stream Networks, Maike F. Holthuijzen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The health of freshwater aquatic systems, particularly stream networks, is mainly influenced by water temperature, which controls biological processes and influences species distributions and aquatic biodiversity. Thermal regimes of rivers are likely to change in the future, due to climate change and other anthropogenic impacts, and our ability to predict stream temperatures will be critical in understanding distribution shifts of aquatic biota. Spatial statistical network models take into account spatial relationships but have drawbacks, including high computation times and data pre-processing requirements. Machine learning techniques and generalized additive models (GAM) are promising alternatives to the SSN model. Two machine learning …

Analysis Of The Hite Fault Group, Southeast Utah: Insights Into Fluid Flow Properties In A Reservoir Analog, Daniel J. Curtis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In the subsurface faults can act as both barriers and conduits for fluids or gases such as CO₂, hydrocarbons, or water. It is often thought that faults in porous rocks such as sandstone are barriers to fluid flow. In this study we show that this is not always the case. In sandstones like the Cedar Mesa Sandstone it is very important to understand the relationships between this history of fault slip and fluid flow. Better understanding of how fluids migrate through faults and the damaged areas surrounding these faults has strong significance to the oil and gas industry. …

Neutro-Connectedness Theory, Algorithms And Applications, Min Xian

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Connectedness plays an important role in human cognitive and learning activities. Human vision system is very sensitive to the connectedness property of objects and effective in "calculating" the property. The study of connectedness will help us explore the way of human brain extracting the global properties of objects, and enable different avenues to design new artificial intelligent (AI) systems with better performances.

However, connectedness is rarely considered in current AI systems because of the lack of complete theoretic system and efficient computation algorithm. In this work, I focus on building the connectedness theory and algorithms in digital space, and apply …

29-Day Analysis Of Scale Heights And The Inference Of The Topside Ionosphere Over Millstone Hill During The 2002 Incoherent Scatter Radar Campaign, Jennifer L. Meehan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study aims to characterize the topside ionospheric density and temperature profiles using readily available Global Positioning System (GPS) total electron content (TEC) and ionosonde bottomside profile of electron density. The aim of this study is to find a technique that can be applied globally rather than specific locations where a wealth of data exists. Knowledge of the distribution of electron density and its altitude dependence, known as scale height, is important for ionospheric empirical modeling and ionospheric studies, and for practical applications, such as time delay correction of radiowave propagation through the ionosphere.

Over the years, researchers have gathered …

Quantifying Riverbed Sediment Using Recreational-Grade Side Scan Sonar, Daniel Hamill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Colorado River in Glen, Marble, and Grand Canyons is subject to a complex regulatory framework, including the Colorado River Compact, the Endangered Species Act, and the Grand Canyon Protection Act of 1992. Physical, biological, and cultural resources are extensively monitored by the Glen Canyon Dam Adaptive Management Program (GCDAMP) to assess the effect of Glen Canyon Dam (GCD) operations on the downstream environment. The GCDAMP consists of a diverse group of stakeholders who identify priority resources and agree upon water releases at GCD. Large expenditures of money have been devoted to monitoring physical and biological resources in Grand Canyon. …

A Tournament Approach To Price Discovery In The Us Cattle Market, Jeffrey Wright

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Cattle price discovery is a process of determining the price in the market through the interactions of cattle buyers (packers) and sellers (ranchers). Locating the price discovery center or market, and estimating price interactions among the regional fed cattle markets and also among feeder cattle markets can help define a relevant fed cattle procurement market. This research identifies that the U.S. cattle markets is discovered in the futures markets, feeder cattle futures and fed futures.

Great Basin Bristlecone Pine Resistance To Mountain Pine Beetle: An Evaluation Of Dendroctonus Ponderosae Host Selection Behavior And Reproductive Success In Pinus Longaeva, Erika L. Eidson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The mountain pine beetle (Dendroctonus ponderosae) is a native bark beetle that attacks and kills most species of pines (Pinus) throughout its range in western North America. Due to the strong relationship between thermal conditions and mountain pine beetle population success, climate change-induced changes in mountain pine beetle outbreaks are a major concern for land managers. Over the past several decades, warmer than average temperatures allowed mountain pine beetle populations to reach epidemic levels across much of the western U.S. and Canada, including high elevations where outbreaks were previously limited by cool temperatures. Many high-elevation pine …

Spatial And Behavioral Patterns Of Captive Coyotes, Jeffrey T. Schultz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Environmental enrichment is a technique used at many captive animal facilities that can improve the well-being of their animals. It seeks to enhance habitat features and promote natural behavior by providing a variety of practical ways for captive animals to control their environmental settings, especially during stressful circumstances. Enclosure features, such as shelter structures, are one tool that promotes wild behavior by adding complexity to an enclosure’s physical environment. Enrichment efforts for captive wildlife are most effective when they are specialized to the biological needs of the animals. Human activity may alter captive animal behavior and utility of enclosure features, …