Physical Sciences and Mathematics Commons^™

Conservation Genetics Of A Declining Bumble Bee In Western North America; The Influence Of Geography, Dispersal Limitation, And Anthopogenic Activity, Ashley T. Rohde

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Conservation biology addresses the problem of species loss by identifying species in need of protection. Conservation biology has subfields to address different aspects of biodiversity loss, including genetics and sociology. I used genetic approaches to assess the conservation status of western bumble bees, a bumble bee species of conservation concern.

The western bumble bee is a bumble bee species that ranges from Alaska to New Mexico and as far east as Wyoming and Colorado. This species is disappearing in some places. It may soon be listed as endangered in the United States and is already listed as endangered in parts …

Redefining Nba Basketball Positions Through Visualization And Mega-Cluster Analysis, Alexander L. Hedquist

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Basketball players have historically been classified based on one of five positions, namely Point Guards, Shooting Guards, Small Forwards, and Centers. While grouping players into these five categories may provide general descriptions of their perceived role, these standard positions fall short of describing players based on their true abilities and performance. This MS thesis proposes a method to group players of the National Basketball Association (NBA) from the past 20 seasons into more meaningful and specific player positions. We systematically group these players into nine distinct categories, and we draw from a vast array of visualization tools, techniques, and software …

An Introduction To Combinatorics Via Cayley's Theorem, Jaylee Willis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In this paper, we explore some of the methods that are often used to solve combinatorial problems by proving Cayley’s theorem on trees in multiple ways. The intended audience of this paper is undergraduate and graduate mathematics students with little to no experience in combinatorics. This paper could also be used as a supplementary text for an undergraduate combinatorics course.

Geometry- And Accuracy-Preserving Random Forest Proximities With Applications, Jake S. Rhodes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Many machine learning algorithms use calculated distances or similarities between data observations to make predictions, cluster similar data, visualize patterns, or generally explore the data. Most distances or similarity measures do not incorporate known data labels and are thus considered unsupervised. Supervised methods for measuring distance exist which incorporate data labels and thereby exaggerate separation between data points of different classes. This approach tends to distort the natural structure of the data. Instead of following similar approaches, we leverage a popular algorithm used for making data-driven predictions, known as random forests, to naturally incorporate data labels into similarity measures known …

Adapting To Low Colorado River Flows And Storage: Lessons From 3 Computer Exercises, David E. Rosenberg

Publications

As Colorado River flows and reservoir levels decline, discussion is ramping up about adapting operations to low flow and storage because existing operations adapt only to storage. This post reviews three recent computer exercises that adapted Colorado River operations to low flow and low storage. Three final paragraphs synthesize lessons to build towards more equitable and sustainable operations.

Uncertainties Of The Pulsed Electroacoustic Method: Peak Positions Of Embedded Charge Distributions, Zachary Gibson, J. R. Dennison

Physics Student Research

The pulsed electroacoustic (PEA) method allows for nondestructive measurements of internal charge distributions in dielectric materials. These measurements have been paramount in understanding and mitigating charge accumulation, aging, and electrostatic discharge in materials for various applications. This study aims to examine more closely the uncertainties of pulsed electroacoustic measurements. The first few moments of a charge distribution are directly related to the magnitude, peak position, full-width-at-half-maximum, and skewness. The uncertainty in the magnitude of the charge distribution is often quite large, but the peak position can be determined with a precision of <1 μm. This has been demonstrated in our lab with repeated PEA measurements of polyether-etherketone (PEEK) with internal charge present. This precision is further validated with measurements of PEEK irradiated with differing doses of 50 keV incident electrons, resulting in peak positions that differ by only a few μm. A final test is given by measurements monitoring the slow migration of the charge distributions in these irradiated samples over several months. The measured shifts in the peak position of the charge distributions are ≤1 μm. Though the spatial resolutions of PEA measurements are typically ~10 μm, as defined by the full- width-at-half-maximum of the leading interfacial peak, the precision of the peak position can be more than an order of magnitude greater. The statistical analysis of the repeated measurements to determine uncertainties, as well as the validation measurements, demonstrate the high precision determination of the peak position of embedded charge distributions.

What Is A Photon? Foundations Of Quantum Field Theory, Charles G. Torre

All Physics Faculty Publications

This is a brief, informal, and relatively low-level course on the foundations of quantum field theory. The prerequisites are undergraduate courses in quantum mechanics and electromagnetism.

Evidence For Multiple Potential Drivers Of Increased Phosphorus In High-Elevation Lakes, J. Scholz, Janice Brahney

Watershed Sciences Faculty Publications

Total phosphorus (TP) concentrations have increased in many remote mountain waterbodies across the western United States, and reports of algal blooms in these systems have increased in frequency. Explanations for observed TP increases are uncertain, and typical landscape drivers, such as agricultural/urban runoff, are implausible. We investigated multiple atmospheric and terrestrial-P loading mechanisms to explain the observed decadal increase in TP, including a novel hypothesis that warming soils may lead to elevated P fluxes to receiving water bodies. Using northern Utah mountains ranges as a case study, we measured prospective inputs of total and bioavailable P via dust deposition. Terrestrial …

Using Smart Foodscapes To Enhance The Sustainability Of Western Rangelands, Juan J. Villalba

Funded Research Records

No abstract provided.

Introduction To Classical Field Theory, Charles G. Torre

All Complete Monographs

This is an introduction to classical field theory. Topics treated include: Klein-Gordon field, electromagnetic field, scalar electrodynamics, Dirac field, Yang-Mills field, gravitational field, Noether theorems relating symmetries and conservation laws, spontaneous symmetry breaking, Lagrangian and Hamiltonian formalisms.

Collaborative Research: Surface-Specific Aerosol Chemistry: Direct Observations, Kinetics, And Environmental Impact, Yi Rao

Funded Research Records

No abstract provided.

Normal-Mode Oscillations For The Circular And Dipolar States Of A Filled Hexagonal Magnetic Dipole Cluster, Peter T. Haugen, Andrew D. P. Smith, Boyd F. Edwards

All Physics Faculty Publications

We analyze the rotational dynamics of six magnetic dipoles of identical strength at the vertices of a regular hexagon with a variable-strength dipole in the center. The seven dipoles spin freely about fixed axes that are perpendicular to the plane of the hexagon, with their dipole moments directed parallel to the plane. Equilibrium dipole orientations are calculated as a function of the relative strength of the central dipole. Small-amplitude perturbations about these equilibrium states are calculated in the absence of friction and are compared with analytical results in the limit of zero and infinite central dipole strength. Normal modes and …

Model Averaging In Agriculture And Natural Resources: What Is It? When Is It Useful? When Is It A Distraction?, Philip M. Dixon

Conference on Applied Statistics in Agriculture and Natural Resources

I use two examples to illustrate three methods for model averaging: using AIC weights, using BIC weights, and fully Bayesian analyses. The first example is a capture-recapture study that estimates the population size by averaging over 4 models for capture probabilities. The second is an analysis of a study of logging impacts on Curculionid weevils using a before-after-control-impact (BACI) study design. The estimated impact is averaged over 4 ecologically relevant models.

Both examples demonstrate the sensitivity of model weights, or posterior model probabilities, to the choice of prior model probabilities and prior distributions for parameters. The model averaged estimates and …

A Robust Clustering Method Using Compositional Data Restrictions: Studying Wood Properties In The Reforestation Of Portugal, Pamela M. Chiroque-Solano, Guido A. Moreira

Conference on Applied Statistics in Agriculture and Natural Resources

Classification of multivariate observations while preserving the data’s natural restriction is a challenge. Special properties such as identifiability, interpretability, and others need to be cared for to build a new approach. To avoid these complications, many transformation algorithms have been developed to use traditional models.In this context, the aim of this work is to propose a robust probabilistic distance algorithm to classify compositional data. Based on the probabilistic distance (PD) clustering approach, the proposal identifies clusters minimizing a joint distance function, JDF, which is part of a dissimilarity measure. This measure combines the PD clustering approach with the density of …

Random Regression For Modeling Semen Fertility In Hf Purebred And Crossbred Bulls Using A Bayesian Framework, Vrinda Ambike, R. Venkataramanan, S. M. K. Karthickeyan, K. G. Tirumurugaan, Kaustubh Bhave, M. Swaminathan

Conference on Applied Statistics in Agriculture and Natural Resources

Data on insemination records of Holstein Friesian (HF) purebred (n=45,497) and crossbred (n=58,497) collected from the BAIF Research Foundation were utilized. The conception rate was modeled as a binary trait, using linear repeatability models. Random regression models (RRM) were used to obtain the trajectory of variance components across age of the bulls. Legendre Polynomials up to order of fit of 4 were used for the random effects of additive genetic and permanent environmental effects. 200,000 Gibbs samples were generated with a burn-in of 20,000 and thinning interval of 50 using the THRGIBBS1F90 program. Heritability estimates were very low (0.1) in …

Principal Response Curve Analysis Of Arthropod Community Abundance Data With Sparse Subsets, Changjian Jiang, C. R. Brown, P. Asiimwe, Chen Meng, Adam W. Schapaugh

Conference on Applied Statistics in Agriculture and Natural Resources

Principal response curve (PRC) analysis was applied to an assessment of the ecological impact of the genetically-modified (GM), insect-resistant, cotton MON 88702 on predatory Hemiptera communities in the field. The field community was represented by ten taxa collected ten times across the season at six sites, in which individual taxa were not observed in at least 25% of the time (unique site x collection combinations). These complete absences and those nearly so, called sparse subsets of the data in this investigation, were the result of geoclimatic and seasonal variations, which are both independent of the treatment effect for which the …

Handling Non-Detects With Imputation In A Nested Design: A Simulation Study, Rose Adjei, John R. Stevens

Conference on Applied Statistics in Agriculture and Natural Resources

In this paper, a simulation study was conducted to assess whether it is ideal to address the issue of non-detects in data using a traditional substitution approach for non-detects, imputation, or a non-imputation based approach. Simulated data used were simple nested designs motivated by a real-life data in a study of bumble bee activity in a commercial cherry orchard by Kuivila et al. (2021). The simulated data were generated at different thresholds or censoring levels and at different effect sizes. For each simulated data, seven popular existing techniques to handle non-detects were applied: (i) Zero substitution, (ii) Substitution with half …

Overview Of Optimal Experimental Design And A Survey Of Its Expanse In Application To Agricultural Studies, Stephen J. Walsh

Conference on Applied Statistics in Agriculture and Natural Resources

Optimal Design of Experiments is currently recognized as the modern dominant approach to planning experiments in industrial engineering and manufacturing applications. This approach to design has gained traction among practitioners in the last two decades on two-fronts: 1) optimal designs are the result of a complicated optimization calculation and recent advances in both computing efficiency and algorithms have enabled this approach in real time for practitioners, and 2) such designs are now popular because they allow the researcher to ‘design for the experiment’ by working constraints, cost, number of experiments, and the model of the intended post-hoc data analysis into …

To The Moon And Mars And Back To The Archives: Working With Modern Space Collections At The University Of Arizona Libraries, Molly Stothert-Maurer, Lisa E. Duncan

Journal of Western Archives

With a long history at the University of Arizona with excellence in the lunar and planetary sciences, the University of Arizona Libraries Special Collections has increased its collecting of the History of Science and Technology. These large, modern space collections pose unique challenges and require specific needs to be addressed in order for the collections to be stored, processed and made available for access. It is essential for archivists working with these collections to ask their donors the right questions and learn the limitations and restrictions that often come with acquiring modern space collections. Archives around the country have started …

Quantifying Impacts Of Grazing And Poor Land Management Strategies On Erosion Through A Semi-Automated Change Detection Workflow In Ka’Amola, Molokai, L. Kalai Ellis, Richard A. Gill

Utah Space Grant Consortium

A challenge faced by those working in a system plagued by non-native vegetation invasion and disturbance from ungulates is the ability to collect landscape-level information about land cover change and the mass movement of soils associated pulsed rainfall events. Our goal was to conduct high-precision change detection of land cover and surface features during a two-year period that included several mass sediment flux events associated with tropical storms. We present here preliminary results of the development and testing of a rule set based classification algorithm used to classify imagery from 2019 and 2021 of a single watershed in Molokai to …

Aerodynamic Effects Of Phase Offset Between Synchronized Propellers In Hover, Nathan Welker, Daniel Maynes

Utah Space Grant Consortium

Emerging advances in electric-propulsion technology are enabling aircraft to use distributed electric propulsion (DEP) to increase efficiency and maneuverability. The implementation of DEP effectively decreases the spacing between propellers, introducing complex aerodynamic interactions that are not well understood. This study presents the use of stereoscopic particle image velocimetry (SPIV) to obtain 3D velocity measurements of the flow fields of phase locked and synchronized propellers at close proximity in a side-by-side configuration. These experiments were performed to explore the aerodynamic effect of phase offset between the propellers. It was found that while the propeller interactions cause an induced upwash and a …

Biophysical Factors Control Invasive Grass Hot Spots In The Mojave Desert, Tanner C. Smith, Tara B. B. Bishop, Michael C. Duniway, Ryan R. Jensen, Richard A. Gill

Utah Space Grant Consortium

Invasive annual grasses are a nuisance in the American Southwest through promotion of the grass-fire cycle. Annual grasses such as Bromus rubens, Bromus tectorum, Schismus barbatus, and Schismus arabicus have invaded the Mojave Desert and increased fire occurrence, thus it is important to identify and characterize the areas where persistent invasion has occurred and subsequently fire risk is increased by understanding the distribution of these invasive grasses. Here we use a remote sensing framework to map persistent and productive populations of invasive annual grass, called hot spots, in the entire Mojave Desert ecoregion over 12 years, identify …

Progress Report: Covid-19 Hotspot Detection In University Campus Settings, Garrett Duncan, William F. Christensen, Camilla Handley

Utah Space Grant Consortium

The COVID-19 pandemic caused a lot of disruption in the academic world. Many schools and universities shut down entirely and transitioned to online learning. As BYU made the transition back to in-person learning, the administration needed to know if there was in-class transmission happening on campus in order to regulate restrictions and keep students and faculty safe. Using demographic information about the students, we built an XGBoost model that produces an estimated probability of testing positive for each student. We incorporated engineered variables from the demographic information as well. We evaluated model fit using metrics such as AUC. Using a …

Internal Wave Generation By Multiple Peak Topographies, Natsha Wilson, Julie Crockett

Utah Space Grant Consortium

Internal waves are generated in the oceans and atmosphere and play an important role in their energy budgets. The semidiurnal oscillation of the tides over topography in the oceans combined with the density stratification can create internal waves that radiate away from their source. The effect of multiple peaks on a single topography has on internal wave generation is explored. Initial results begin to show that multiple ridges create two parallel IW beams with smaller IWs between them compared to the single beam created by a one ridge topography. Kinetic energy is also tightly clustered at lower wavenumbers in Fourier …

Exploration Of An Electrochemical Sensor For Continuous Monitoring Of Estradiol In Application To Fertility Tracking, Julia S. Dominesey, Shad J. Roundy

Utah Space Grant Consortium

Estradiol is one of three estrogens, the primary female sex hormone; it fluctuates diurnally, and monthly, dictating the menstrual cycle. We developed a bench-top electrochemical sensor to detect estradiol with the intention of future realization into an implantable, continuously sampling sensor to be used as an aid for fertility health. The electrochemical sensor is comprised of a three electrode system which utilizes a gold working electrode, platinum counter electrode, and Ag/AgCl reference electrode to perform cyclic voltammetry. A monolayer of estradiol aptamers and mercaptohexanethiol coat the working electrode surface. The monolayer was exposed to 10ng/mL, 100n/mL and 1,000ng/mL of estradiol. …

Refill Friction Stir Spot Welding As An Alternative Jointing Method For Wing Spar Structures, Paul Blackhurst, Yuri Hovanski, Andrew Curtis

Utah Space Grant Consortium

Refill Friction Stir Spot Welding (RFSSW) is an emerging solid state joining process for thin sheet aluminum. Many researchers are developing RFSSW process parameters, thus enabling the use of RFSSW in many industries. Some work within this development has been on the application of RFSSW to wing spar stringer and skin joining. This is thanks to the RFSSW process being capable of welding the high-strength aluminum alloys used for wing spar construction. Traditionally wing spar joining has been achieved using rivets. This newer method has the potential to improve the strength, reduce the weight, and lower the cost of wing …

Development Of Optical Systems For In-Situ Measurements Of High-Temperature Combustion Plumes, Cara Frischkorn, Stephen A. Whitmore

Utah Space Grant Consortium

Results from proof-of-concept tests using fiber-optic cables inserted into the combustion port of a lab-scale hybrid rocket system are reported. The fiber optic cables transmit optical signals to miniature spectrometers and allow in-situ optical characterization of the combustion plume properties including flame temperature and combustion plume species. Multiple firings with burn durations varying from 5 to 25 seconds were performed. The fiber optic sensors survived all tests and resulting rocket performance data were correlated with in-situ optical spectra data. When the optical measurements were adjusted to account for the spectrometer transfer function and the resulting spectra were curve-fit to Planck's …

Ionosphere/Thermosphere Dynamics Obtained From Cosmic Satellite Observations, Layne Pedersen, Ludger Scherliess

Utah Space Grant Consortium

The morphology and climatology of thermospheric neutral winds play an important role in ionospheric and thermospheric dynamics. Thermospheric neutral winds effect temporal and spatial variations of ionospheric plasma which plays an important role F-region dynamics. However, direct observations of thermospheric neutral winds are historically limited both temporally and spatially [1]. For example, interferometric methods for measuring thermospheric winds are restricted to nighttime observations and cloudless conditions and are limited to relatively few locations. Space-based observations made by cross-track measurements from accelerometers as well as onboard interferometers and spectrometers provide valuable information of thermospheric winds but coverage is inconsistent over a …

Acoustic Analysis Of The Delta Iv Heavy Launch Vehicle, Griffin Houston, Grant W. Hart, Kent L. Gee

Utah Space Grant Consortium

The Delta IV Heavy is an orbital heavy class launch vehicle that has been in operation since 2004. In this study, the overall sound power level and other acoustic properties of the Delta IV Heavy launch vehicle will be calculated and analyzed. Five data acquisition systems with a wide frequency bandwidth were placed in a far-field arc around a 2021 launch. Using a weighted mean to compare results across stations, a maximum overall sound pressure level (OASPL) of 140 dB and an average maximum polar directivity angle of 69 deg were calculated. An overall sound power level of 198 dB …

Selecting Appropriate Axis Of Movement For Accurate Breath Detection, Magaly Sencion, Joe Orr, Lara Brewer

Utah Space Grant Consortium

Opioid-Induced Respiratory Depression can be characterized as a severe side effect of opioid therapy that is well known for causing high mortality rates in the postoperative period. Other than suppressing various respiration parameters, like those such as respiration rate or tidal volume, the effects of opioids can lead to irregular breathing patterns.

A 3-axis accelerometer has been proposed as an affordable respiratory sensor to detect suppressed respiratory drive. The challenge is to identify the best signal of three recorded axes.

In this study, we tested an algorithm that could automatically detect the best signal of the three recorded axes (x,y, …