Physical Sciences and Mathematics Commons^™

Starships & The Physics Of Interstellar Travel, Shane L. Larson

Public Talks

No abstract provided.

Connections To The Cosmos: The Search For Life Beyond Earth, Shane L. Larson

Public Talks

No abstract provided.

A Transition-Phase Teleconnection Of The Pacific Quasi-Decadal Oscillation, Shih-Yu (Simon) Wang, R. R. Gillies, L. E. Hipps, J. Jin

Plants, Soils, and Climate Faculty Publications

The atmospheric circulation patterns associated with the Pacific quasi-decadal oscillation (QDO) are investigated using available observational data from 1948 to 2007. Previous studies indicate that the Pacific QDO is characterized by a distinct lifecycle in the form of sea surface temperature (SST) patterns. In the warm and cool phases of the Pacific QDO, the SST patterns resemble those associated with the El Niño-Southern Oscillation (ENSO). During the warm–cool and cool–warm transitions of the Pacific QDO, recurrent SST patterns are also clearly visible. The rotated empirical orthogonal function analysis on the 10–15 year filtered data shows that the evolutions of SST …

Lunar Dependent Equatorial Ionospheric Effects During Sudden Stratosphericwarmings, Bela G. Fejer, M. E. Olson, J. L. Chau, C. Stolle, H. Luhr, L. P. Goncharenko, K. Yumoto, T. Nagatsuma

Bela G. Fejer

[1] We have used plasma drift and magnetic field measurements during the 2001–2009 December solstices to study, for the first time, the longitudinal dependence of equatorial ionospheric electrodynamic perturbations during sudden stratospheric warmings. Jicamarca radar measurements during these events show large dayside downward drift (westward electric field) perturbations followed by large morning upward and afternoon downward drifts that systematically shift to later local times. Ground-based magnetometer measurements in the American, Indian, and Pacific equatorial regions show strongly enhanced electrojet currents in the morning sector and large reversed currents (i.e., counterelectrojets) in the afternoon sector with onsets near new and full …

Assessment Of Utah Bankruptcies By Census Tracts: A Spatial Statistical Approach, Kenneth Pena

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

There are two questions raised when looking at the spatial pattern of the rate of bankruptcies in Utah: (i) are there similarities between the bankruptcy data in adjacent census tracts and (ii) can local cluster and outliers be identified within the data? Specifically, are there similar rates of bankruptcies in bordering census tracts and are there any localized areas of interest where we find extremely high or extremely low rates of bankruptcies? This study uses spatial statistics to perform tests for spatial autocorrelation to address these two questions. It also looks at commonalities in the clusters and differences in the …

Improving Accuracy Of Large-Scale Prediction Of Forest Disease Incidence Through Bayesian Data Reconciliation, Ephraim M. Hanks

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Increasing the accuracy of predictions made from ecological data typically involves replacing or replicating the data, but the cost of updating large-scale data sets can be prohibitive. Focusing resources on a small sample of locations from a large, less accurate data set can result in more reliable observations, though on a smaller scale. We present an approach for increasing the accuracy of predictions made from a large-scale eco logical data set through reconciliation with a small, highly accurate data set within a Bayesian hierarchical modeling framework. This approach is illustrated through a study of incidence of eastern spruce dwarf mistletoe …

Numerical Solution Of The Five-Moment Ideal Two-Fluid Equations In One Dimension, Marcus Scott

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Plasmas are frequently treated as a single conducting fluid and modeled using the equations of magnetohydrodynamics. However, this regime works better for low-frequency plasmas. High-frequency plasmas may be modeled using the principles of kinetic theory. For plasmas with frequencies between these two extremes, a two-fluid approach can yield better results. In 2006, Ammar Hakim mathematically modeled a plasma with a set of equations called the five-moment ideal two-fluid equations. An attempt is made reproduce those results. A derivation of this set of equations by taking moments of the Boltzmann equation is presented. Electric and magnetic fields contribute to the source …

Assessing The Precision And Accuracy In A Small Sample Of Actical Devices, Peter Sherick

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Actigraphy is an increasingly popular approach in medicine to assess patient activity levels in a variety of scenarios. The devices are essentially accelerometers encased in a write-watch type assembly. This project sought to determine the device precision and accuracy for the Actical model. In a sample of four Acticals, it was found that intra-device variability was minimal. However, one device was found to be statistically biased in comparison to the other three. This bias could have adverse effects on aggregated or magnitude dependent data analysis. Also, inter-device comparisons may be problematic.

Grading Practice Influence On The Value Of An Assigned Grade, Carrie Bala

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

This article presents results of a study of grading practice influence on the value of an assigned grade. The value of an assigned grade, as an indication of student achievement of learning goals, was measured using the Utah Criterion-Referenced Test (CRT) in the subjects of Geometry and Algebra 2. The grading policies of six mathematics teachers at the same high school were categorized according to grading practice and their combined 587 students' scores on the Utah CRT were collected and analyzed. The findings suggest that certain grading practices , such as the use of a 1-4 scale and a criterion-referenced …

Assessing North American Influenza Dynamics With Hierarchical Spatio-Temporal Models, Jessica Anderson

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

We present a general statistical modeling framework to characterize continental-level influenza dynamics in the United States for the purposes of examining state-level epidemiological sources and sinks. The methods we describe depend directly on state-level influenza data that are updated weekly and available on the internet. Advances in search engine query analysis have provided powerful new tools for collecting epidemiological data and, when used in conjunction with sophisticated statistical models, allow for the identification and quantification of the flow of influenza across the continental United States. Our proposed methods, when conditioned on this comprehensive search query product, can provide unprecedented scientific …

A Comparison Of Prediction Methods Of Functional Autoregressive Time Series, Devin Didericksen

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Functional data analysis (FDA) is a relatively new branch of statistics that has seen a lot of expansion recently. With the advent of computer processing power and more efficient software packages we have entered the beginning stages of applying FDA methodology and techniques to data. Part of this undertaking should include an empirical assessment of the effectiveness of some of the tools of FDA, which are sound on theoretical grounds. In a small way, this project helps advance this objective.

This work begins by introducing FDA, scalar prediction techniques, and the functional autoregressive model of order one - FAR(1). Two …

Simulating Power For One-Way Anova By Using Non-Normal Error Distributions, Caixia Xu

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Usually we assume that the distribution of the additive errors in a one-way ANOVA linear model is normal. However, exceptions to this assumption about the error distribution may exist. In such cases, we might consider non-normal error distributions, but proceed with the "usual" ANOVA F-test analyses. This study focuses on simulating power for one-way ANOVA when using non-normal error distributions.

Statistical Analysis Of Wastewater Remediation And Bio-Fuels Production Of Algae, Jay D. Jones

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The Logan city wastewater treatment system consists of a series of seven large aerated ponds (460 acres) that biologically treats 15 million gallons per day of wastewater from Logan city and six other communities. Tighter regulations of allowed phosphorus levels in the effluent have recently been implemented due to environmental concerns of a downstream reservoir. The Biological Engineering program at Utah State University, the Bio-fuels Center, the Utah Water Research Laboratory (UWRL) and the city of Logan are working together to remediate the wastewater treatment system using microalgae. Algal growth requires the uptake of phosphorus. Thus, phosphorus in the effluent …

Evolving Models: A Density-Based Approach To Modeling Sexual Dimorphism And Adaptive Speciation, Audrey Smith

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

In this paper, we begin by extending existing deterministic and individual-based ecological models for sexual dimorphism and adaptive speciation into density-based mathematical models describing the density or number of individuals with various trait values, or phenotypes. These density-based models describe the dynamics of a population of males and females using both clonal and sexual reproduction. Each generation, the populations are subject to mating, mutation, and ecological dynamics including infraspecific competition and carrying capacity of the environment. By avoiding individual-based models, we are able to avoid simulations and instead achieve repeatable results.

Implementing these models numerically, we are able to show …

Absence Of Predation Eliminates Coexistence: Experience From The Fish-Zooplankton Interface, Z. M. Gilwicz, Wayne A. Wurtsbaugh, E. Szymansk

Watershed Sciences Faculty Publications

Examples from fishless aquatic habitats show that competition among zooplankton for resources instigates rapid exclusion of competitively inferior species in the absence of fish predation, and leads to resource monopolization by the superior competitor. This may be a single species or a few clones with large body size: a cladoceran such as Daphnia pulicaria, or a branchiopod such as Artemia franciscana, each building its population to a density far higher than those found in habitats with fish. The example of zooplankton from two different fish-free habitats demonstrates the overpowering force of fish predation by highlighting the consequences of its absence. …

Impact Of The Farmington Bay Eutrophication Plume On The Plankton Ecology Of Gilbert Bay, Great Salt Lake, Joe Crawford, Erin Fleming, Ashton Montrone, Meagan Wilcox, Jaclyn Wight

Watershed Sciences Student Research

Farmington Bay in the Great Salt Lake is hypereutrophic because of extreme nitrogen and phosphorus loading, largely from greater metropolitan Salt Lake City sewage effluents. Although this causes detrimental impacts within the bay, the influence of the outflow of its algal- and nutrient-rich waters into Gilbert Bay is largely unknown. To address this issue, students in the 2010 Aquatic Ecology Practicum course from Utah State University did a 13-km long transect analysis of trophic parameters from the causeway bridge separating the two bays, out into the pelagic zone of Gilbert Bay (Figure 1; Appendix A). On the September 30^{th …}

The Effects Of Surface Modification On Spacecraft Charging Parameters, Amberly Evans, John R. Dennison

All Physics Faculty Publications

Charging of materials by incident radiation is affected by both environmental and physical conditions. Modifying a material’s physical surface will change its reflection, transmission and absorption of the incident radiation which are integrally related to the accumulation of charge and energy deposition in the material. An optical analysis of the effect of surface modification on spacecraft charging parameters on prototypical Kapton HN and Cu samples is presented. Samples were roughened with abrasive compounds ranging from 0.5 to 10 μm in size, comparable to the range of incident wavelengths. They were also contaminated with thin layers of DC 704 diffusion pump …

Spacecraft Coating-Induced Charging: A Materials And Modeling Study Of Environmental Extreme, Michelle M. Donegan, Jennifer L. Sample, John R. Dennison, R. Hoffman

All Physics Faculty Publications

As mankind reaches to explore extreme environments in space, the application of ceramics surface coatings is increasing. The 2005 mission concept for Solar Probe used a unique design to achieve the necessary thermal control for a very close approach to the solar corona, including the use of a highly refractory, electrically insulating ceramic coating over a carbon-carbon composite heat shield. The proposed trajectory takes the spacecraft from a Jovian fly-by to within 4 solar radii of the Sun, spanning 5 orders of magnitude in solar radiation and solar wind plasma density as well as spacecraft temperatures from <100 K to >2000 K. Using …

A Passive Sampler For Ambient Gaseous Oxidized Mercury Concentrations, Seth N. Lyman, Mae Sexauer Gustin, Eric M. Prestbo

USU Uintah Basin Faculty Publications

This paper reports on the development of a passive sampler for estimating gaseous oxidized mercury concentrations. Atmospheric gaseous oxidized mercury concentrations calculated from passive sampler data were correlated with those obtained using an automated analyzer (r2 = 0.71, p < 0.01, n = 110 for one-week deployments; r2 = 0.89, p < 0.01, n = 22 for two-week deployments). Sampler uptake was not significantly affected by changes in temperature, humidity, or ozone concentration, but it was slightly dependent on wind speed. As such, an equation for correcting data due to this factor was developed based on wind tunnel and field data. The detection limit for a two-week sampler deployment was ∼5 pg m−3. Field data collected in Nevada and the southeastern United States showed these samplers are useful for investigating spatial and temporal variability in gaseous oxidized mercury concentrations.

Neuraminidase Activity Of Influenza Virus Strains That Differ In The Ability To Cause Disease, Benjamin Hanks Brown, Bart Tarbet

Browse All Undergraduate research

Influenza viruses are classified based on their surface glycoproteins: hemagglutinin and neuraminidase. Hemagglutinin (HA) is responsible for binding to the host cell, while neuraminidase (NA) facilitates escape of newly formed virus particles. These studies determined the NA activity of three subtypes of influenza A virus that differ in their ability to cause disease in mice: influenza A/NWS/33 (H1N1), influenza A/Victoria/3/75 (H3N2), and influenza A/Duck/MN/1525/81 (H5N1). Chemiluminescent quantitation of NA activity in equal amounts of each virus was determined in three replicate experiments. Results indicate that N1 virus subtypes have higher NA activity than do N2 subtypes. In addition, the NA …

Rehabilitate Failing Park Sewage System Environmental Assessment, United States Department Of The Interior, National Park Service

Environmental Assessments (UT)

The National Park Service (NPS) proposes to rehabilitate the failing sewage system within Bryce Canyon National Park, Utah. The rehabilitation would provide a safe, healthy, and functional environment, and maintain public health and future service for park visitors and staff. Portions of the sanitary sewage collection system were originally constructed in 1958 of clay pipe and currently service the lodge, staff housing, and visitor center before feeding into sewage treatment lagoons. Sections of the sewage system have deteriorated significantly with age. These sections of the system and appurtenant manholes are deteriorating into pieces that regularly clog the system and cause …

Environmental Assessment: Proposed Agricultural Research Center, Utah State University Campus, Logan, Utah, Sage Environmental

Environmental Assessments (UT)

Assess the environment on which Utah State University proposes to establish a new facility for the College of Agriculture

Tree Rings And Earthquakes, Matthew F. Bekker

Wasatch Dendroclimatology Research

The lithosphere, earth’s rigid outer shell comprising crust and upper mantle rock, is broken into about 14 tectonic plates (Christopherson 2009) that move a few centimeters per year over superheated, pliable rock underneath. Forces within earth’s interior push, pull and twist the plates in different directions, producing three types of plate boundaries: convergent (colliding with one another), divergent (moving away from one another) and transform (sliding past one another). Earthquakes occur when plates become locked together, building strain between and within them that is suddenly released, sending a burst of seismic waves that cause shaking and displacement of the surface. …

Fire Disturbance, Forest Structure, And Stand Dynamics In Montane Forests Of The Southern Cascades, Thousand Lakes Wilderness, California, Usa, Matthew F. Bekker, Alan H. Taylor

Wasatch Dendroclimatology Research

We examined tree diameter, age structure, and successional trends in 100 montane forest plots to identify the effects of variation in the return interval, severity, and extent of fires on forest structure and dynamics in the southern Cascade Range, California. We classified 100 forest plots into 8 groups based on stand structural characteristics. Median point fire return intervals were shortest in lower montane mixed conifer and Jeffrey pine–white fir stands (13-25 y) and upper montane red fir–white fir stands (14.5-19.5 y), intermediate in lodgepole pine stands (50-76.5 y), and longest in high-elevation red fir–mountain hemlock stands (100 y). Fire severity …

Understanding Space Weather Customers In Gps-Reliant Industries, Jennifer L. Meehan, G. Fisher, W. Murtagh

All Physics Faculty Publications

Since the last solar maximum, society has become extremely reliant on the Global Positioning System (GPS), which is often referred to as the “fourth utility” behind electricity, water, and natural gas. As the economy depends more and more on positioning, navigation, and timing, society's vulnerability to space weather continues to increase because space weather can be a significant cause of GPS errors. Critical applications such as railway control, highway traffic management, precision agriculture, emergency response, commercial aviation, and marine navigation all require GPS services. With such widespread and critical usage, industries are becoming more aware of how space weather can …

Does Chiasmus Appear In The Book Of Mormon By Chance?, Boyd F. Edwards, W. F. Edwards

All Physics Faculty Publications

Chiasmus is an inverted-parallel literary form that was employed by ancient Hebrew biblical writers, among others. An instance of this form, called a “chiasm,” presents two or more literary elements, and then restates them in reverse order. Short chiasms are not uncommon in literature. In some cases, the authors undoubtedly intended to use that form for literary effect (that is, by design); in other cases, the elements fell into that form without author intent (that is, by chance). In 1969, John W. Welch reported his discovery of many-element chiasms in the Book of Mormon,1 which Joseph Smith testified to …

Observations Of Prolific Transient Luminous Event Production Above A Mesoscale Convective System In Argentina During The Sprite2006 Campaign In Brazil, F. T. São Sabbas, Michael J. Taylor, Pierre-Dominique Pautet, T. Berkey, S. Cummer, R. R. Azambuja, J. P.C. Santiago, J. N. Thomas, O. Pinto Jr., N. N. Solorzano, N. J. Schuch, S. R. Freitas, N. J. Ferreira, J. C. Conforte

All Physics Faculty Publications

On the night of 22–23 February 2006, 444 transient luminous events (TLEs), 86% sprites, were observed above a prolific mesoscale convective system (MCS) over Argentina, as part of the third sprite campaign in Brazil. GOES infrared (IR) cloud top temperatures (Tc) and Tropical Rainfall Measuring Mission (TRMM) radar (PR) and microwave (TMI) data were used to investigate the MCS convective characteristics and their relationship with World Wide Location Network (WWLLN) detected cloud‐to‐ground (CG) lightning and TLE activity. The MCS had a minimum lifetime of 20 hours, 8.5 as a MCS, a maximum extent of ∼430,000 km2, and gusty winds of …

Measurement Methods Of Electron Emission Over A Full Range Of Sample Charging, R. Hoffman, John R. Dennison

All Physics Faculty Publications

The electron emission properties of a material subject to incident radiation flux are key parameters in determining to what equilibrium charge a spacecraft will established under given environmental conditions. However, there is a complex relation between these emission properties and the charge built up in spacecraft insulators. Complex modeling codes have been developed to predict the potential a spacecraft will adopt as a consequence of its interaction with the space plasma. These require correct models of the electron yields as a function of charge to accurately predict the both the charge build up and the equilibrium potential of spacecraft components. …

When Are Chiasms Admissible As Evidence?, Boyd F. Edwards, W. F. Edwards

All Physics Faculty Publications

Since John Welch’s discovery of chiasmus in the Book of Mormon in 1967, many critics have attempted to show how chiasmus appears in just about every type of literature, from Dr. Seuss to Strangite scripture. This article discusses the authors’ statistical admissibility tests to verify whether a chiasmus in a work shows strong evidence of intentionality by the original author. Their results indicate that certain passages in the Old Testament and in the Book of Mormon show deliberate chiasmus, while Strangite scripture, the Doctrine and Covenants, nursery rhymes, Dr. Seuss, and other works are not intentionally chiastic.

Approximation Of Range In Materials As A Function Of Incident Electron Energy, Gregory Wilson, John R. Dennison

All Physics Faculty Publications

A simple composite analytic expression has been developed to approximate the electron range in materials. The expression is applicable over more than six orders of magnitude in energy (10 MeV) and range (10-9 m to 10-2 m), with uncertainty of ≤20% for most conducting, semiconducting and insulating materials. This is accomplished by fitting data from two standard NIST databases [ESTAR for the higher energy range and the electron IMFP (inelastic mean free path) for the lower energies]. In turn, these data have been fit with well-established semi-empirical models for range and IMFP that are related to standard materials properties (e.g., …