Physical Sciences and Mathematics Commons^™

Spatial Analyses Of Trophic Linkages Between Basins In The Great Salt Lake, Wayne A. Wurtsbaugh, David Naftz, Shane Bradt

Watershed Sciences Faculty Publications

Although the Great Salt Lake is frequently treated as if it were a single body of water, the natural bays and transportation causeways have divided it into a system of four bays. The bays, however, do not function independently because water, nutrients and other contaminants flow between them. The purpose of our study was to analyze the water quality in three of the bays (Farmington, Bear River and Gilbert), to determine fluxes of nutrients between them, and to determine how this was influencing brine shrimp populations in the lake. Discharge and nutrient concentrations were measured at constrictions separating the three …

Approximate String Matching With Dynamic Programming And Suffix Trees, Leng Hui Keng

UNF Graduate Theses and Dissertations

The importance and the contribution of string matching algorithms to the modern society cannot be overstated. From basic search algorithms such as spell checking and data querying, to advanced algorithms such as DNA sequencing, trend analysis and signal processing, string matching algorithms form the foundation of many aspects in computing that have been pivotal in technological advancement.

In general, string matching algorithms can be divided into the categories of exact string matching and approximate string matching. We study each area and examine some of the well known algorithms. We probe into one of the most intriguing data structure in string …

P2pcompute - A Peer-To-Peer Computing Model, Jayant Mishra

UNF Graduate Theses and Dissertations

Peer-to-peer (P2P) networks consist of nodes which have both client and server capabilities and on which communication and data sharing is carried on directly between nodes, rather than being arbitrated by an intermediary node. The P2P architecture was popularized by file-sharing, one of the widely-used applications of the Internet. Many applications that are based on this architecture have been developed. It also provides an efficient platform to harness the computing power of a network of desktop computers. P2P computing power can help solve computationally complex problems that require powerful supercomputers. However, it has not been as widely used as the …

Wavelet-Based Index Of Magnetic Storm Activity, A. Jach, Piotr Kokoszka, Jan Josef Sojka, Lie Zhu

All Physics Faculty Publications

A wavelet-based method of computing an index of storm activity is put forward. The new index can be computed automatically using statistical procedures and does not require selecting quiet days and removing the secular component by polynomial fitting. This 1-min index is designed to facilitate the study of the fine structure of geomagnetic storm events and requires only the most recent magnetogram records, e.g., the 2 months including the storm event of interest. It can thus be computed over a moving window as soon as new magnetogram records become available. Averaged over 1-hour periods, it is practically indistinguishable from the …

Utah State University Global Assimilation Of Ionospheric Measurements Gauss-Markov Kalman Filter Model Of The Ionosphere: Model Description And Validation, Ludger Scherliess, Robert W. Schunk, Jan Josef Sojka, Donald C. Thompson, Lie Zhu

All Physics Faculty Publications

The Utah State University Gauss-Markov Kalman Filter (GMKF) was developed as part of the Global Assimilation of Ionospheric Measurements (GAIM) program. The GMKF uses a physics-based model of the ionosphere and a Gauss-Markov Kalman filter as a basis for assimilating a diverse set of real-time (or near real-time) observations. The physics-based model is the Ionospheric Forecast Model (IFM), which accounts for five ion species and covers the E region, F region, and the topside from 90 to 1400 km altitude. Within the GMKF, the IFM derived ionospheric densities constitute a background density field on which perturbations are superimposed based on …

Anomalous F Region Response To Moderate Solar Flares, C. G. Smithtro, Jan Josef Sojka, T. Berkey, Donald C. Thompson, Robert W. Schunk

All Physics Faculty Publications

Ionograms recorded with a dynasonde at Bear Lake Observatory, Utah, during moderate solar x-ray flares exhibit characteristic enhancements to the E and F 1 region ionosphere. However, during these same flares, the peak electron density of the ionosphere (N m F 2) unexpectedly decreases, recovering after the flare ends. In order to reconcile this anomalous behavior with expected increases to the total electron content (TEC), we undertake a modeling effort using the Time-Dependent Ionospheric Model (TDIM) developed at Utah State University. For solar input, a simple flare time irradiance model is created, using measurements from the Solar EUV Experiment instrument …

Probability Tails Of Wavelet Coefficients Of Magnetometer Records, Piotr Kokoszka, I. Maslova, Jan Josef Sojka, Lie Zhu

All Physics Faculty Publications

The ground-based magnetometer network has long been a powerful tool for monitoring and observing the variations of the currents flowing in the magnetosphere-ionosphere (M-I) system. The time series of magnetograms are nonstationary and their frequency behavior changes over time. They are therefore not amenable to traditional time domain or spectral (Fourier) analysis. In recent years, various new mathematical techniques have been developed to analyze magnetometer data and the wavelet technique has stood out as being particularly relevant. In order to correctly make statistical inferences based on wavelet analysis, the wavelet coefficient distributions of magnetograms must be examined. In this work, …

Uniqueness Of Solutions To The Helically Reduced Wave Equation With Sommerfeld Boundary Conditions, Charles G. Torre

All Physics Faculty Publications

We consider the helical reduction of the wave equation with an arbitrary source on (n+1)-dimensional Minkowski space, n ≥ 2. The reduced equation is of mixed elliptic-hyperbolic type on Rn. We obtain a uniqueness theorem for solutions on a domain consisting of an n-dimensional ball B centered on the reduction of the axis of helical symmetry and satisfying ingoing or outgoing Sommerfeld conditions on ∂B ≈ Sn−1. Nonlinear generalizations of such boundary value problems (with n = 3) arise in the intermediate phase of binary inspiral in general relativity.

Observables For The Polarized Gowdy Model, Charles G. Torre

All Physics Faculty Publications

We give an explicit characterization of all functions on the phase space for the polarized Gowdy 3-torus spacetimes which have weakly vanishing Poisson brackets with the Hamiltonian and momentum constraint functions.

E-Field Dependent Conduction In Low-Density Polyethylene, Jerilyn Brunson, John R. Dennison

All Physics Faculty Publications

Measurements of the resistivity of low density polyethylene (LDPE) samples of varying thickness have been made using the standard constant voltage method to explore electric field dependence using conduction mechanisms developed for amorphous solids and semi-conductors. Resistivity is related to carrier mobility within the bulk. Where electrons are the primary charge carriers, their mobility is dependent on their probability of hopping between trapping sites treated as potential wells. A series of constant voltage measurements at constant temperature show that LDPE follows the Poole-Frenkel theory of field-enhanced conduction at low applied fields.

Gravitational Waves: Just Plane Symmetry, Charles G. Torre

All Physics Faculty Publications

In four spacetime dimensions gravitational plane waves (a special case of the plane-fronted waves with parallel rays) admit a 5 parameter isometry group. We generalize this group to n-dimensions and explore some special features of spacetimes admitting this isometry group. In particular, it is shown that every generally covariant rank-2 symmetric tensor field constructed from a metric with plane wave symmetry will vanish except multiples of the metric and Ricci tensors. We show that, in four spacetime dimensions, a particular enlargement of the plane wave symmetry group is enough to force the group-invariant metrics to satisfy all generally covariant vacuum …

Validation Study Of The Ionospheric Forecast Model Using The Topex Tec Measurements, L. Zhu, Robert W. Schunk, G. Jee, Ludger Scherliess, Jan Josef Sojka, Donald C. Thompson

All Physics Faculty Publications

As a part of the validation program in the Utah State University Global Assimilation of Ionospheric Measurement (GAIM) project, a newly improved Ionosphere Forecast Model (IFM) was systematically validated by using a large database of TOPEX total electron content (TEC) measurements. The TOPEX data used for the validation are for the period from August 1992 to March 2003, and the total number of 18-s averaged data is close to 11 million. This model validation work covers a wide range of seasonal (winter, summer, and equinox) and solar (low-F 10.7, median F 10.7, and high-F 10.7) conditions as well as all …

Extreme Longitudinal Variability Of Plasma Structuring In The Equatorial Ionosphere On A Magnetically Quiet Equinoctial Day, Sarah E. Mcdonald, Sunanda Basu, Santimay Basu, Keith M. Groves, Cesar E. Valladares, Ludger Scherliess, Donald C. Thompson, Robert W. Schunk, Jan Josef Sojka

All Physics Faculty Publications

We investigate the extreme longitudinal variability of equatorial scintillation under quiet magnetic conditions during 22–23 March 2002. Scintillation Network Decision Aid (SCINDA) observations show intense activity in the South American–Atlantic sector during local evening hours, whereas an absence of scintillation is seen in the far east Asian sector. Ground- and space-based measurements from SCINDA, the Global Ultraviolet Imager (GUVI), TOPEX, and a chain of GPS receivers are used in combination with the Utah State University Global Assimilation of Ionospheric Measurements (USU-GAIM) model to explore the relationship between the large-scale ionization distribution and small-scale irregularities at low latitudes in both the …

Biconformal Matter Actions, A. Wehner, James Thomas Wheeler

All Physics Faculty Publications

We extend 2n-dim biconformal gauge theory by including Lorentz-scalar matter fields of arbitrary conformal weight. We show that for a massless scalar field of conformal weight zero in a torsion-free biconformal geometry, the solution is determined by the Einstein equation on an n-dim submanifold, with the stress-energy tensor of the scalar field as source. The matter field satisfies the n-dim Klein-Gordon equation.

Science Icebreaker Activities: An Example From Gravitational Wave Astronomy, Michelle B. Larson, Louis J. Rubbo, Kristina D. Zaleski, Shane L. Larson

All Physics Faculty Publications

At the beginning of a class, workshop, or meeting, an icebreaker activity is often used to help loosen up the group and get everyone talking. When used as a precursor to group learning, the icebreaker fosters communication so later activities function more smoothly. Science-based icebreaker activities serve the purpose of a traditional icebreaker, while also introducing science content to the audience. The content of the icebreaker may or may not be related to the topic of the upcoming class or meeting. Either way, the activity provides a way to get people talking while the participants simultaneously learn something new and …

Characteristics Of Wave Induced Oscillations In Mesospheric O2 Emission Intensity And Temperature, A. Taori, Michael J. Taylor

All Physics Faculty Publications

Gravity wave and tidal signatures in mesospheric emissions can be characterized using a quantity η which relates the wave intensity perturbations to the corresponding induced temperature oscillation. The quasi-monochromatic wave induced oscillations in the O₂ (0–1) atmospheric emission observed from Maui, Hawaii (20.8 N, 156.2 W) have been investigated for the periods ranging from 1–12 hours. Our results clearly show that ∣η∣ increases from 0.5 to 10 with the increasing wave periods while the phase Ø exhibits a decreasing trend (+75 to −100°). When compared with model, observed trends agree well while significant differences in the absolute values are …

Design And Construction Of A Misse-6 Payload: State Of Utah Space Environment & Contamination Study (Suspecs), Joshua L. Hodges, Jeff Duce, John R. Dennison

All Physics Faculty Publications

No abstract provided.

Gravitational Waves: New Observatories For New Astronomy, Louis J. Rubbo, Shane L. Larson, Michelle B. Larson, Kristina D. Zaleski

All Physics Faculty Publications

This article reviews the current status of gravitational wave astronomy and explains why astronomers are excited about the new generation of gravitational wave detectors. As part of the review we compare and contrast gravitational radiation to the more familiar electromagnetic radiation. We discuss the current indirect experimental evidence for gravitational waves and how current and future gravitational wave detectors will operate as our newest telescopes are pointed at the skies.

Integrated Restoration Strategies Towards Weed Control On Western Rangelands, U.S. Forest Service

Wildlife Conservation and Management

An attempt to find native plant materials competitive with cheatgrass to help break the cheatgrass-fire cycle and begin the transition from exotic annual-dominated vegetation to native perennial dominated vegetation.

Terpenes And Carbohydrate Source Influence Rumen Fermentation, Digestibility, Intake, And Preference In Sheep, J. J. Villalba, F. D. Provenza, K. C. Olson

Green Canyon Environmental Research Area, Logan Utah

We hypothesized that toxins and nutrients in foods interact to influence foraging behavior by herbivores. Based on this hypothesis we predicted that 1) terpenes in big sagebrush (Artemisia tridentata) influence intake and preference in sheep for diets varying in sources of nonstructural (barley grain) and structural (sugar beet pulp) carbohydrates, and 2) these effects are due to the differential effects of terpenes on fermentation products and apparent digestibility of each class of carbohydrates. Lambs were fed 2 isoenergetic and isonitrogenous diets with varying proportions of the same ingredients (beet pulp- and barley grain-based diet) or offered a choice between the …

Logic Circuits And The Quality Of Life, Vincent W. Childress

Publications

The article presents information on the relationship between the logic circuits and the quality of life. The applications of logic circuits are countless. With the flooding of New Orleans in the wake of Hurricane Katrina, people around the world became all too aware of human dependency on technology to manage the forces of nature and maintain a high quality of life. New Orleans' sewage and water control systems depend on water pumps to move sewage, storm-water runoff, and fresh water around the city. Under normal conditions, when it rains in New Orleans, a city that sits below sea level, massive …

Suspects- State Of Utah Space, Environment & Contamnation Study- Misse Vi, Jeff Ducea, Josh Hodgesa, Jacob Geddesa, Andrew Aumana, Sarah Bartona, Jr Dennison, Clint Thomsonc, J. W. Burnsc, L. Pearsonc, L. Davis, R. S. Hydec, James S. Dyerd

Posters

A Study of the effects of prolonged exposure to the space environment and of charge-enhanced contamination on the electron emission and resistivity of spacecraft materials, the State of Utah Space Environment & Contamination Study (SUSpECTS), is planned for flight aboard the MISSE-6 payload. the Materials International Space month exposure periods on-orbit on the International Space Station, with a target flight date of mid-2006. The study is conducted by the Utah State University Materials that contamination can lead to catastrophic charging effects under certain circumstances, little direct information is presently available on the effects of sample deterioration and on emission properties …

Structural Evolution And Vorticity Of Flow During Extrusion And Exhumation Of The Greater Himalayan Slab, Mount Everest Massif, Tibet/Nepal: Implications For Orogen-Scale Flow Partitioning, M. J. Jessup, R. D. Law, M. P. Searle, Mary S. Hubbard

Geosciences Faculty Publications

The Greater Himalayan Slab (GHS) is composed of a north-dipping anatectic core, bounded above by the South Tibetan detachment system (STDS_ and below by the Main Central thrust zone (MCTZ). Assuming simultaneous movement on the MCTZ and STDS, the GHS can be modelled as a southward-extruding wedge or channel. New insights into extrusion-related flow with the GHS emerge from detailed kinematic and vorticity analyses in the Everest region. At the highest structural levels, mean kinematic vorticity number (Wm) estimates of 0.74-0.91 (c. 45-28% pure shear) were obtained from sheared Tethyan limestone and marble from the Yellow Band on Mount Everest. …

Mineralogical Characterization Of Protolith And Fault Rocks From The Safod Main Hole, John G. Solum, Stephen H. Hickman, David A. Lockner, Diane E. Moore, Ben A. Van Der Pluijm, Anja M. Schleicher, James P. Evans

Geosciences Faculty Publications

Washed cuttings provide a continuous record of the rocks encountered during drilling of the main hole of the San Andreas Fault Observatory at Depth (SAFOD). Both protolith and fault rocks exhibit a wide variety of mineral assemblages that reflect variations in some combination of lithology, P-T conditions, deformation mechanisms, and fluid composition and abundance. Regions of distinct neomineralization bounded by faults may record alteration associated with fluid reservoirs confined by faults. In addition, both smectites occurring as mixed-layer phases and serpentine minerals are found in association with active strands of the San Andreas Fault that were intersected during drilling, although …

Enhanced Cerenkov Second-Harmonic Generation In Patterned Lithium Niobate, Cong Deng, Joseph W. Haus, Andrew Sarangan, Aziz Mahfoud, Concita Sibilia, Michael Scalora, Aleksei M. Zheltikov

Electro-Optics and Photonics Faculty Publications

We present experimental results of second harmonic generation enhancement through the resonance of the band edge in a photonic crystal based on lithium niobate. Proton exchange technique was used to fabricate a waveguide near the surface of the lithium niobate substrate. The photonic crystal structure over the waveguide was made by UV laser interferometry. Subsequently experiments were designed to quantify the Cerenkov second-harmonic generation (CSHG) radiated into the substrate. The SHG radiated inside the waveguides was also experimentally investigated. In our experiments, the second guided mode of the waveguide was tuned to the band edge resonance to enhance the second …

Recent Developments Inthe Mechanistic Enzymology Of The Atp-Dependent Lon Protease From Escherichia Coli: Highlights From Kinetic Studies, Irene Lee, Anthony J. Berdis, Carolyn K. Suzuki

Chemistry Faculty Publications

Lon protease, also known as protease La, is one of the simplest ATP-dependent proteases that plays vital roles in maintaining cellular functions by selectively eliminating misfolded, damaged and certain short-lived regulatory proteins. Although Lon is a homo-oligomer, each subunit of Lon contains both an ATPase and a protease active site. This relatively simple architecture compared to other hetero-oligomeric ATP-dependent proteases such as the proteasome makes Lon a useful paradigm for studying the mechanism of ATP-dependent proteolysis. In this article, we survey some recent developments in the mechanistic characterization of Lon with an emphasis on the utilization of pre-steady-state enzyme kinetic …

Microstructural Analysis Of A Drill Core From The Rhode Island Formation: Upper 750 Feet, Ashlee Kirkwood

Undergraduate Review

No abstract provided.

The Investigation Of Screening Of Chromoelectric And Chromomagnetic Fields In Noncovariant Gauges, Elşen Veli̇, Jale Yilmazkaya Süngü

Turkish Journal of Physics

According to Thermal Quantum Chromodynamics (TQCD) hadron matter may exist in the form of quark-gluon plasma (QGP) at high temperatures and densities. The aim of the present work is to investigate the screening of chromoelectric and chromomagnetic fields in QGP in noncovariant gauges. In noncovariant gauges, gluon propagator has unphysical poles and singularities appear in the gluon self-energy diagram calculations. In this paper, we investigate gluon self-energy in lightcone and temporal gauges. In order to remove singularities, we use the Mandelstam-Leibbrandt prescription (ML prescription). We obtain that chromoelectric fields are screened, but chromomagnetic fields are not screened. In coordinate space, …

Investigation Of The Multipolarity Of Electromagnetic Transitions In ^{88,90}Kr Nuclei, Nuretti̇n Türkan, Davut Olgun, İhsan Uluer, Sai̇t İnan

Turkish Journal of Physics

We have determined the most appropriate Hamiltonian that is needed for present calculations of nuclei about the A \cong 80 region by the view of Interacting Boson Model-2 (IBM-2). After obtaining the best Hamiltonian parameters, level energies and B(E2) probabilities of some transitions in ^{88,90}Kr nuclei were estimated. Results are compared with previous experimental and theoretical data and it is observed that they are in good agreement. Finally, R_1 = \frac{B(E2;4_1 \to 2_1)}{B(E2;2_1 \to 0_1)}, R_2 = \frac{B(E2;2_2 \to 2_1)}{B(E2;2_1 \to 0_1)}, \ R_3 = \frac{B(E2;0_2 \to 2_1)}{B(E2;2_1 \to 0_1)}, R_4 = \frac{{B(E2;2_2 \to 0_1)}{B(E2;2_2 \to 2_1)}, R_5 = \frac{B(E2;3_1 …

Peculiarities Of The Electric And Thermoelectric Properties Of Gate, M. M. Nassary

Turkish Journal of Physics

Measurements of electrical conductivity, Hall coefficient and thermoelectric power were carried out over the temperature range 136--563 K for GaTe compound grown in single crystal form by modified Bridgman technique. The crystals obtained had Positive-type conductivity with a hole concentration of 3.8 \times 10^{12} cm^{-3} at room temperature. Conductivity and Hall mobility at room temperature were evaluated as 4.4 \times 10^{-3} ohm^{-1} cm^{-1} and 7079 cm^2/V \cdot s, respectively. The energy gap width of 1.5 eV was found. The effective mass of holes and electrons at room temperature were 4.16 m_° and 0.1174 m_° , respectively