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Articles 811 - 840 of 7340

Full-Text Articles in Physical Sciences and Mathematics

Hodographic Analysis Of Na Lidar Data To Measure Atmospheric Gravity Wave Parameters, Jeffrey Ormsby Aug 2020

Hodographic Analysis Of Na Lidar Data To Measure Atmospheric Gravity Wave Parameters, Jeffrey Ormsby

Physics Capstone Projects

The Utah State University Sodium lidar observatory, hosted in Science and Engineering Research building at Logan campus, measures the winds and temperature near the boundary of eddy diffusion dominated upper atmosphere between 80 and 110-km, where various atmospheric internal waves, especially atmospheric gravity waves (buoyancy waves), play important roles in the dynamics and chemistry. In this study, using a hodographic algorithm, the lidar data were analyzed to extract critical parameters of these gravity waves detected in this region, such as horizontal propagating phase velocity and wavelength. Results were compared with the independent Advanced Atmospheric Temperature Mapper (AMTM) observations, co-located at …


Massive Graviton Spectra In Supergravity, Kevin Dimmitt Aug 2020

Massive Graviton Spectra In Supergravity, Kevin Dimmitt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Development of a unified theory of physics would pave the way for new research and technology development for many years to come. Unfortunately, the two best current theories explaining nature, the Standard Model of particle physics and general relativity, do not seem to be compatible, requiring the development of more complicated models which contains both of these at their respective limits. Supergravities are one set of theories which may, at least in part, provide hints as to how it may be possible to unify physics into a single model.

This research project follows from a line of investigation which the …


Methods In Modeling Wildlife Disease From Model Selection To Parameterization With Multi-Scale Data, Ian Mcgahan Aug 2020

Methods In Modeling Wildlife Disease From Model Selection To Parameterization With Multi-Scale Data, Ian Mcgahan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of emerging wildlife diseases are global and profound, resulting in loss of human life, economic and agricultural impacts, declines in wildlife populations, and ecological disturbance. The spread of wildlife diseases can be viewed as the result of two simultaneous processes: spatial spread of wildlife populations and disease spread through a population. For many diseases these processes happen at different timescales, which is reflected in available data. These data come in two flavors: high-frequency, high-resolution telemetry data (e.g. GPS collar) and low-frequency, low-resolution presence-absence disease data. The multi-scale nature of these data makes analysis of such systems challenging. Mathematical …


Automating And Analyzing Whole-Farm Carbon Models, Aditi Maheshwari Aug 2020

Automating And Analyzing Whole-Farm Carbon Models, Aditi Maheshwari

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The goal of this research is to learn about whole farm carbon models. A whole farm carbon model estimates the emissions of greenhouse gasses (GHGs) based on information for a farm. We analyzed two models, HOLOS whole-farm and COMET-Farm, by running the models on random inputs and building classifiers from the runs. HOLOS estimates GHG emissions for a particular year based on crop and animal agriculture input, while COMET-farm adds past and future farm management practices. Users of the models must manually enter farm data through a graphical user interface (GUI), which is a good method for a single farm, …


Connections Between Hydrothermal System Geochemistry And Microbiology: Traversing Tectonic Boundaries In The South-Central Peruvian Andes, Heather Upin Aug 2020

Connections Between Hydrothermal System Geochemistry And Microbiology: Traversing Tectonic Boundaries In The South-Central Peruvian Andes, Heather Upin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Geochemistry and microbiology are inherently tied in the natural world. The study of geomicrobiology has historically taken place in extreme systems, like hot springs of Yellowstone National Park and deep-sea hydrothermal vents, because the organisms that exist there have deep lineages on the tree of life and provide insight into early life on Earth. These microbes use chemical energy from nutrients available in their environment rather than relying on photosynthesis, energy obtained from the sun, to support their metabolism. The goal of this study is to improve our understanding of geological controls (for example the tectonic setting) on hot spring …


Geomorphic History Of The Grand Staircase Region Of The Colorado Plateau: Understanding Arroyo Cut-Fill Dynamics, Erosion Rates, And Wildfire, Kerry E. Riley Aug 2020

Geomorphic History Of The Grand Staircase Region Of The Colorado Plateau: Understanding Arroyo Cut-Fill Dynamics, Erosion Rates, And Wildfire, Kerry E. Riley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Most streams in the southwestern United States do not flow all year, and given their delicate balance of sediment and water flow, they are sensitive to climate change. At the turn of the 20th century, many streams in the Southwest rapidly incised into their floodplains, forming arroyos with a channel entrenched into near-vertical channel banks mostly composed of sand and mud. This dissertation investigates past changes in watersheds draining the Grand Staircase region in southern Utah with the goal of understanding how changes in climate and sediment influence these types of streams. Results show sediment supply is highly variable across …


Greening-Induced Runoff Loss In The Western United States, Xueyan Zhang Aug 2020

Greening-Induced Runoff Loss In The Western United States, Xueyan Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study assessed how vegetation will influence long-term runoff trends across the western United States (western US) in the future. I used a land surface model with improved dynamic vegetation root processes to better quantify regional runoff trends across five regions (Upper and Lower Colorado, Great Basin, Pacific Northwest, and California). The model was driven by statistically downscaled and bias-corrected outputs from three global climate models under the Representative Concentration Pathway 4.5 and 8.5 scenarios. Vegetation greening dominated significant transpiration increases that contributed most to increasing evapotranspiration across the western US, especially during spring and summer. Consistent with these trends, …


Facial Expression Recognition In The Wild Using Convolutional Neural Networks, Amir Hossein Farzaneh Aug 2020

Facial Expression Recognition In The Wild Using Convolutional Neural Networks, Amir Hossein Farzaneh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Facial Expression Recognition (FER) is the task of predicting a specific facial expression given a facial image. FER has demonstrated remarkable progress due to the advancement of deep learning. Generally, a FER system as a prediction model is built using two sub-modules: 1. Facial image representation model that learns a mapping from the input 2D facial image to a compact feature representation in the embedding space, and 2. A classifier module that maps the learned features to the label space comprising seven labels of neutral, happy, sad, surprise, anger, fear, or disgust. Ultimately, …


A Stratospheric Approach To Diagnose The North American Winter Dipole, Henrik Panosyan Aug 2020

A Stratospheric Approach To Diagnose The North American Winter Dipole, Henrik Panosyan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

It has been well established in the literature that the stratosphere is dynamically coupled with the troposphere during boreal winter. The North American Winter Dipole is comprised of an upper-tropospheric contrast between a ridge over western North America, and a trough over eastern North America. The variance of this circulation regime has increased in recent years, with its amplified states being associated with extremes ranging from drought and floods, to extreme cold air outbreaks. This study explores the stratospheric link to this extreme weather regime, in the hopes of ultimately improving the predictability of this regime on intraseasonal-to-seasonal timescales. We …


Universal Localizations Of Certain Noncommutative Rings, Tyler B. Bowles Aug 2020

Universal Localizations Of Certain Noncommutative Rings, Tyler B. Bowles

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A common theme throughout algebra is the extension of arithmetic systems to ones over which new equations can be solved. For instance, someone who knows only positive numbers might think that there is no solution to x + 3 = 0, yet later learns x = -3 to be a feasible solution. Likewise, when faced with the equation 2x = 3, someone familiar only with integers may declare that there is no solution, but may later learn that x = 3/2 is a reasonable answer. Many eventually learn that the extension of real numbers to complex numbers unlocks solutions …


Machine Learning Enhanced Free-Space And Underwater Oam Optical Communications, Patrick L. Neary Aug 2020

Machine Learning Enhanced Free-Space And Underwater Oam Optical Communications, Patrick L. Neary

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Communications, bandwidth, security, and hardware simplicity are principles of interest to society at large. Recent advances in optics and in understanding properties of light, such as orbital angular momentum (OAM), have provided new potential mediums for communication.

Machine learning has wound its way into a broad range of fascinating areas. An emerging field of research is the use of a unique property of lasers called orbital angular momentum (OAM). With the proper hardware, a laser can go from a Gaussian shaped distribution to a doughnut shaped pattern, where the radius can be changed. Multiple OAM patterns, or modes, can be …


Social Justice Mathematical Modeling For Teacher Preparation, Patrick L. Seegmiller Aug 2020

Social Justice Mathematical Modeling For Teacher Preparation, Patrick L. Seegmiller

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Today's math teachers face significant social and political challenges for which they receive little preparation. Mathematics content courses can potentially provide additional preparation in this regard by providing future teachers with experiences to mathematically explore social justice issues. This provides them with opportunities to increase their awareness and sensitivity to social justice issues, develop greater empathy for their future students, and serve as examples for high quality instruction that they can emulate in their future careers. This dissertation recounts the development and revision of three social justice mathematical modeling projects, and shares evidence from student work samples of the ways …


Load Forecasting Analysis Using Contextual Data And Integration With Microgrids Used For Off Grid Ev Charging Stations, Ashit Neema Aug 2020

Load Forecasting Analysis Using Contextual Data And Integration With Microgrids Used For Off Grid Ev Charging Stations, Ashit Neema

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Electricity is an essential component of the smooth working of every sector. If a successful prediction of how much electricity will be required for say the next 24 hours or 48 hours can be made, it will not only help in efficiently planning the activities and operations but also help in minimizing the cost incurred. In this thesis the same is being attempted, first, a model is created that can predict the energy consumption of households using various tools available. To achieve this, historical data of the past 5 years that has been recorded in London has been used. Secondly, …


Boron In The Pariette Wetlands, Uinta Basin, Ut, Palak Vasudeva Aug 2020

Boron In The Pariette Wetlands, Uinta Basin, Ut, Palak Vasudeva

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Boron is a naturally occurring mineral in shale and coal beds formed in marine environments, as found in the Uinta Basin. Mining activity and the application of excess irrigation water on agricultural lands in the Pariette watershed lead to mobilization of B via surface run off. Water quality monitoring records from 2006- 2009 reported violations of Utah B standard for irrigation water 43-100% of the time, for water flowing through the Pariette Wetlands. This study aims to determine B distribution in abiotic (water, sediments) and biotic samples (macroinvertebrates, aquatic vegetation, fish, bird eggs), and to establish correlations between B concentrations …


Effect Of Plant Derived Tannins On Nitrogen And Carbon Cycling In Pasture Soils, Kathryn A. Slebodnik Aug 2020

Effect Of Plant Derived Tannins On Nitrogen And Carbon Cycling In Pasture Soils, Kathryn A. Slebodnik

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pasture-finished beef has become increasingly popular, but nitrogen losses from these pastures are of concern. Legumes containing condensed tannins such as birdsfoot trefoil (Lotus corniculatus) and sainfoin (Onobrychis viciifolia) may serve as environmentally and economically viable alternative forages in pasture finishing systems while reducing soil nitrogen loss. The goal of this project was to understand how tannin type and concentration affects soil nitrogen cycling both in the lab and the field. This thesis: 1) compared the physical, chemical, and biological characteristics of soil samples obtained from grazed grass and tannin and non-tannin containing legume pastures, 2) …


Some Examples Of The Liouville Integrability Of The Banded Toda Flows, Zachary Youmans Aug 2020

Some Examples Of The Liouville Integrability Of The Banded Toda Flows, Zachary Youmans

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Toda lattice is a famous integrable system studied by Toda in the 1960s. One can study the Toda lattice using a matrix representation of the system. Previous results have shown that this matrix of dimension n with 1 band and n‚àí1 bands is Liouville integrable. In this paper, we lay the foundation for proving the general case of the Toda lattice, where we consider the matrix representation with dimension n and a partially filled lower triangular part. We call this the banded Toda flow. The main theorem is that the banded Toda flow up to dimension 10 is …


Soil Health Assessment On Arid Rangeland Soils Impacted By Oil And Gas Exploration, Development, And Extraction, Justin Allred Aug 2020

Soil Health Assessment On Arid Rangeland Soils Impacted By Oil And Gas Exploration, Development, And Extraction, Justin Allred

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Oil and gas well pad reclamation in arid environments such as in the Uinta Basin of Utah, presents unique challenges, including remote locations, limited water, and elevated soil salinity and sodicity. Successfully reclaimed Plugged and Abandoned (P&A) well pads should resemble the surrounding rangeland once fully reclaimed. Revegetation of native species is the primary indicator of successful reclamation, but the lack of water makes it challenging to re-seed native plants, while trying to prevent the encroachment of invasive plant species such as Bromus tectorum (cheatgrass), Salsola tragus (Russian thistle), and Halogeton glomeratus (halogeton). Could successful reclamation be reflective of good …


Visual Saliency Estimation And Its Applications, Fei Xu Aug 2020

Visual Saliency Estimation And Its Applications, Fei Xu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The human visual system can automatically emphasize some parts of the image and ignore the other parts when seeing an image or a scene. Visual Saliency Estimation (VSE) aims to imitate this functionality of the human visual system to estimate the degree of human attention attracted by different image regions and locate the salient object. The study of VSE will help us explore the way human visual systems extract objects from an image. It has wide applications, such as robot navigation, video surveillance, object tracking, self-driving, etc.

The current VSE approaches on natural images models generic visual stimuli based on …


A Bayesian Markov Chain Monte Carlo Approach To Uncertainty Quantification, Matthew Isaac Aug 2020

A Bayesian Markov Chain Monte Carlo Approach To Uncertainty Quantification, Matthew Isaac

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Uncertainty quantification (UQ) is a framework used frequently in engineering analyses to understand how uncertainty in system inputs lead to uncertainty in the system output. An instability is observed in a UQ method proposed by Roy and Oberkampf and a Bayesian Markov Chain Monte Carlo approach to UQ is offered as an alternative. The Bayesian approach allows analysts to incorporate information from various available sources including observed measurements and expert opinion and to update the analysis and results as more information becomes available. An illustrative engineering example is provided as a platform to demonstrate the Bayesian UQ approach and to …


Analyzing The Von Neumann Entropy Of Contact Networks, Thomas J. Brower Aug 2020

Analyzing The Von Neumann Entropy Of Contact Networks, Thomas J. Brower

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

When modeling the spread of disease, ecologists use ecological or contact networks to model how species interact with their environment and one another. The structure of these networks can vary widely depending on the study, where the nodes of a network can be defined as individuals, groups, or locations among other things. With this wide range of definition and with the difficulty of collecting samples, it is difficult to capture every factor of every population. Thus ecologists are limited to creating smaller networks that both fit their budget as well as what is reasonable within the population of interest. With …


Storm-Time Equatorial Thermospheric Dynamics And Electrodynamics, Luis A. Navarro Dominguez Aug 2020

Storm-Time Equatorial Thermospheric Dynamics And Electrodynamics, Luis A. Navarro Dominguez

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We present the first complete study of the dynamics of the equatorial upper atmosphere (180-350 km) during periods of strong magnetic activity driven by the Sun, which are generally referred as geomagnetic storms. These storms have the potential to considerably affect satellite-based communications and navigation systems among other severe technological challenges. We used large databases of two of the most important parameters at these altitudes, which are the velocities of the neutral and ionized gas (plasma) referred to as neutral winds and plasma drifts. These measurements were acquired in the Peruvian equatorial region by the Jicamarca radar and by a …


Nitrogen Fertilizer Needs Of First-Year Small Grains Following Alfalfa, Collin Pound Aug 2020

Nitrogen Fertilizer Needs Of First-Year Small Grains Following Alfalfa, Collin Pound

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wheat, barley, triticale, and oats, are small grains commonly grown as hay and grain following alfalfa in Utah and the Intermountain West, especially during drought years as they require less irrigation than corn. Several studies in many parts of the world have shown that first-year corn following alfalfa rarely needs nitrogen (N) fertilizer, yet relatively few have evaluated the N needs of small grains, especially small grains grown for hay. Objectives of this research were to determine whether N fertilizer is needed to economically optimize the yield and quality of first-year small grains following alfalfa, develop N guidelines, and whether …


An Analysis Of Syntax Exercises On The Performance Of Cs1 Students, Shelsey B. Sullivan Aug 2020

An Analysis Of Syntax Exercises On The Performance Of Cs1 Students, Shelsey B. Sullivan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Students in introductory programming classes (CS1) generally have a difficult time learning the rules of programming. Although the general concepts of programming are relatively easy to learn, it can be difficult to learn what exactly can be typed in what order, which is known as syntax. To attempt to help students overcome this barrier, a study was conducted that introduced exercises into a CS1 class which taught the programming syntax in simple steps. The results of this study were obtained by analyzing the keys the students pressed, the errors of their code, their midterm exam scores, and their responses to …


Development And Identification Of Metrics To Predict The Impact Of Dimension Reduction Techniques On Classical Machine Learning Algorithms For Still Highway Images, Wasim Akram Khan Aug 2020

Development And Identification Of Metrics To Predict The Impact Of Dimension Reduction Techniques On Classical Machine Learning Algorithms For Still Highway Images, Wasim Akram Khan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We are witnessing an influx of data - images, texts, video, etc. Their high dimensionality and large volume make it challenging to apply machine learning to obtain actionable insight. This thesis explores several aspects pertaining to dimensional reduction: dimension reduction methods, metrics to measure distortion, image preprocessing, etc. Faster training and inference time on reduced data and smaller models which can be deployed on commodity hardware are a critical advantage of dimension reduction. For this study, classical machine learning methods were explored owing to their solid mathematical foundation and interpretability.

The dataset used is a time series of images from …


Collaborative Research: Network Cluster: Dust In The Critical Zone From The Great Basin To The Rocky Mountains, Janice Brahney Jul 2020

Collaborative Research: Network Cluster: Dust In The Critical Zone From The Great Basin To The Rocky Mountains, Janice Brahney

Funded Research Records

No abstract provided.


Design, Monitoring And Management Approaches For The Root-Zone In Microgravity, Scott B. Jones Jul 2020

Design, Monitoring And Management Approaches For The Root-Zone In Microgravity, Scott B. Jones

Funded Research Records

No abstract provided.


Using Disaster Outcomes To Validate Components Of Social Vulnerability To Floods: Flood Deaths And Property Damage Across The Usa, Beth Tellman, Cody Schank, Bessie Schwarz, Peter D. Howe, Alex De Sherbinin Jul 2020

Using Disaster Outcomes To Validate Components Of Social Vulnerability To Floods: Flood Deaths And Property Damage Across The Usa, Beth Tellman, Cody Schank, Bessie Schwarz, Peter D. Howe, Alex De Sherbinin

Environment and Society Faculty Publications

Social vulnerability indicators seek to identify populations susceptible to hazards based on aggregated sociodemographic data. Vulnerability indices are rarely validated with disaster outcome data at broad spatial scales, making it difficult to develop effective national scale strategies to mitigate loss for vulnerable populations. This paper validates social vulnerability indicators using two flood outcomes: death and damage. Regression models identify sociodemographic factors associated with variation in outcomes from 11,629 non-coastal flood events in the USA (2008–2012), controlling for flood intensity using stream gauge data. We compare models with (i) socioeconomic variables, (ii) the composite social vulnerability index (SoVI), and (iii) flood …


Fire Suppression Impacts On Fuels And Fire Intensity In The Western U.S.: Insights From Archaeological Luminescence Dating In Northern New Mexico, Christopher I. Roos, Tammy M. Rittenour, Thomas W. Swetnam, Rachel A. Loehman, Kacy L. Hollenback, Matthew J. Liebmann, Dana Drake Rosenstein Jul 2020

Fire Suppression Impacts On Fuels And Fire Intensity In The Western U.S.: Insights From Archaeological Luminescence Dating In Northern New Mexico, Christopher I. Roos, Tammy M. Rittenour, Thomas W. Swetnam, Rachel A. Loehman, Kacy L. Hollenback, Matthew J. Liebmann, Dana Drake Rosenstein

Geosciences Faculty Publications

Here, we show that the last century of fire suppression in the western U.S. has resulted in fire intensities that are unique over more than 900 years of record in ponderosa pine forests (Pinus ponderosa). Specifically, we use the heat-sensitive luminescence signal of archaeological ceramics and tree-ring fire histories to show that a recent fire during mild weather conditions was more intense than anything experienced in centuries of frequent wildfires. We support this with a particularly robust set of optically stimulated luminescence measurements on pottery from an archaeological site in northern New Mexico. The heating effects of an October 2012 …


Comparison Of Accelerated Solvent Extraction (Ase) And Energized Dispersive Guided Extraction (Edge) For The Analysis Of Pesticides In Leaves, Ashlie D. Kinross, Kimberly J. Hageman, William J. Doucette, Alexandria L. Foster Jul 2020

Comparison Of Accelerated Solvent Extraction (Ase) And Energized Dispersive Guided Extraction (Edge) For The Analysis Of Pesticides In Leaves, Ashlie D. Kinross, Kimberly J. Hageman, William J. Doucette, Alexandria L. Foster

Chemistry and Biochemistry Faculty Publications

Various techniques have been evaluated for the extraction and cleanup of pesticides from environmental samples. In this work, a Selective Pressurized Liquid Extraction (SPLE) method for pesticides was developed using a Thermo Fisher Scientific Accelerated Solvent Extraction (ASE) system. This instrument was compared to the newly introduced (2017) extraction instrument, the Energized Dispersive Guided Extraction (EDGE) system, which combines Pressurized Liquid Extraction (PLE) and dispersive Solid Phase Extraction (dSPE). We first optimized the SPLE method using the ASE instrument for pesticide extraction from alfalfa leaves using layers of Florisil and graphitized carbon black (GCB) downstream of the leaf homogenate in …


Coqui Frog Predator Avoidance And Recognition, Karen H. Beard Jul 2020

Coqui Frog Predator Avoidance And Recognition, Karen H. Beard

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The purpose of this study was to determine whether coqui frogs from their non-native range responded to native predators the same way as frogs from their native range. Frogs were collected from two sites in Puerto Rico (El Yunque and Rio Abajo) in May 2006 and one site in Hawaii (Hilo) in June 2006. At each site, frogs were collected from a high (> 700 m) and low (< 300 m) elevation population. Of the total number of frogs collected, 100 males were randomly selected to be used in this study (45 and 55 from Hawaii and Puerto Rico, respectively). Three tailless whipscorpions (Phrynus longipes) and three tarantulas (Avicularia laeta) were also collected in Puerto Rico in field sites where frogs were collected and shipped back to a laboratory.