Physical Sciences and Mathematics Commons^™

Competitive Effects And Equivalence Of Woody And Herbaceous Vegetation In A Young Boreal Mixedwood Stand, Hongan Yan, Phil G. Comeau, D. G. Pitt

North American Forest Ecology Workshop

Mixedwood stands of white spruce (Picea glauca [Moench] Voss) and trembling aspen (Populus tremuloides Michx.) are the major forest type in the boreal forests of western Canada. They contribute significantly to Canada’s wood supply and play important ecological services. Bluejoint grass (Calamagrostis canadensis (Michx.) Beauv.) is also a prominent component of boreal mixedwood ecosystems and can impede natural regeneration of white spruce and negatively affect the development of white spruce and aspen mixedwood stands. Several studies have shown that spruce growth declines with increasing aspen abundance. Hence, competition control is often required to achieve acceptable survival and growth of spruce. …

Overstory And Understory Vegetation Dynamics In Response To Thinning In Coniferous Stands In Western Oregon, Adrian Ares, Andrew R. Neill, Klaus J. Puttmann

North American Forest Ecology Workshop

Thinning even-aged coniferous stands in the Pacific Northwest is aimed at accelerating development of late-successional features, while maintaining long-term forest productivity. We examined effects of thinning on overstory and understory vegetation 11 years after harvest in 40- to 60-year old forests dominated by Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) on three sites in western Oregon. Each site contained an unthinned control (238-1446 tpha) and three thinning treatments selected to enhance overstory structural diversity by decreasing densities, and enhance spatial variability within stands (high density = 120 tpha; moderate density = 80 tpha; variable thin with 120, 80 and 40 tpha with …

Whitebark Pine As A Foundation And Keystone Species: Functional Roles And Community Interactions, Diana Tomback

North American Forest Ecology Workshop

Whitebark pine (Pinus albicaulis), a non-commercial five-needle white pine (Family Pinaceae, Subgenus Strobus), and the only North American stone pine (Subsection Cembrae), inhabits upper subalpine and treeline zones throughout the western United States and Canada. The most northerly in distribution of western North American white pines, it occurs across 18∞ of latitude and 21∞ of longitude, and comprises diverse community types--successional, climax, and treeline, mesic to xeric, and pure to mixed associations. Studies within the last three decades have elucidated a unique ecology for whitebark pine, derived in part from obligate seed dispersal by Clarkís nutcrackers, but also from its …

Forest Histories & Forest Futures, Cathy Whitlock

North American Forest Ecology Workshop

The climate changes projected for the future will have significant consequences for forest ecosystems and our ability to manage them. It is reasonable to ask: Are there historical precedents that help us understand what might happen in the future or are historical perspectives becoming irrelevant? What synergisms and feedbacks might be expected between rapidly changing climate and land–use in different settings, especially at the wildland–urban interface? What lessons from the past might help us plan for a changing world? Information on forest history comes from a variety of sources, including pollen and charcoal preserved in lake sediments spanning millennia, variations …

Flight Experiments On The Effects Of Contamination On Electron Emission Of Materials, John R. Dennison, Joshua L. Hodges, Jeff Duce, Amberly Evans

All Physics Faculty Publications

We report on a study of the effects of prolonged exposure to the space environment and of chargeenhanced contamination on the electron emission and resistivity of spacecraft materials. The State of Utah Space Environment & Contamination Study (SUSpECS) was deployed on the International Space Station (ISS) in March 2008 onboard the MISSE-6 payload during STS-123. The Materials International Space Station Experiment (MISSE-6) program is designed to characterize the performance of candidate new space materials over the course of its ~17 month exposure to the LEO environment, with a target return date of August 2009 on STS-127. Approximately 165 samples are …

The First Frontier: High Altitude Ballooning As A Platform For Student Research Experiences In Science And Engineering, Shane L. Larson, John C. Armstrong, William A. Hiscock

All Physics Faculty Publications

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High altitude balloon platforms are ideal for providing hands-on research experiences for students in physics, atmospheric science, engineering, and other aerospace-related disciplines. We describe a basic high altitude balloon platform that can be constructed and operated by undergraduate students. The existing HARBOR and BOREALIS programs are used to illustrate some possible science and engineering research projects that students can pursue as part of a high-altitude flight program.

Electron Densities In The Lower Thermosphere From Guvi 135.6 Nm Tomographic Inversions In Support Of Spreadfex, F. Kamalabadi, J. Comberiate, Michael J. Taylor, Pierre-Dominique Pautet

All Physics Faculty Publications

The SpreadFEx campaign was conducted with the goal of investigating potential neutral atmospheric dynamics influences in seeding plasma instabilities and bubbles extending to higher altitudes from September to November 2005, with primary measurements in Brazil. In this paper, we present the results of space-based UV and ground-based optical observations in support of this campaign. Specifically, we present multi-dimensional electron density images obtained tomographically from the 135.6 nm emissions measured by the GUVI instrument aboard the TIMED satellite that result from radiative recombination of O+ and compare those with the corresponding 630.0 nm OI images recorded in the Brazilian sector. The …

Simultaneous Observations Of Equatorial F-Region Plasma Depletions Over Brazil During The Spread-F Experiment (Spreadfex), Pierre-Dominique Pautet, Michael J. Taylor, N. P. Chapagain, H. Takahashi, A. F. Medeiros, F. T. São Sabbas, D. C. Fritts

All Physics Faculty Publications

From September to November 2005, the NASA Living with a Star program supported the Spread-F Experiment campaign (SpreadFEx) in Brazil to study the effects of convectively generated gravity waves on the ionosphere and their role in seeding Rayleigh-Taylor instabilities, and associated equatorial plasma bubbles. Several US and Brazilian institutes deployed a broad range of instruments (all-sky imagers, digisondes, photometers, meteor/VHF radars, GPS receivers) covering a large area of Brazil. The campaign was divided in two observational phases centered on the September and October new moon periods. During these periods, an Utah State University (USU) all-sky CCD imager operated at S˜ao …

Impact Of The Intraseasonal Variability Of Large-Scale Circulation Over The Western North Pacific On The Characteristics Of Tropical Cyclone Track, T. C. Chen, Shih-Yu (Simon) Wang, M. C. Yen, A. J. Clark

Plants, Soils, and Climate Faculty Publications

The life cycle of the Southeast Asian–western North Pacific monsoon circulation is established by the northward migrations of the monsoon trough and the western Pacific subtropical anticyclone, and is reflected by the intraseasonal variations of mo nsoon westerlies and trad e easterlies in the form of an east–west seesaw oscillation. In this paper, an effort is made to disclose the influence of this monsoon circulation on tropical cyclone tracks during its different ph ases using composite charts of large-scale circulation for certain types of tracks. A majority of straight-moving (recurving) tropical cyclones appear during weak (strong) monsoon west- erlies and …

The Spread-F Experiment (Spreadfex): Program Overview And First Results, David C. Fritts, M. A. Abdu, B. R. Batista, I. S. Batista, P. P. Batista, R. Buriti, B. R. Clemesha, T. Dautermann, E. De Paula, B. J. Fechine, Bela Fejer, D. Gobbi, J. Haase, F. Kamalabadi, B. Laughman, L. M. Lima, H. L. Liu, A. Medeiros, Pierre-Dominique Pautet, D. M. Riggin, F. São Sabbas, J. H. A. Sobral, P. Stamus, H. Takahashi, Michael J. Taylor, Sharon L. Vadas, C. M. Wrasse

Publications

We performed an extensive experimental campaign (the spread F Experiment, or SpreadFEx) from September to November 2005 to attempt to define the role of neutral atmosphere dynamics, specifically wave motions propagating upward from the lower atmosphere, in seeding equatorial spread F and plasma bubbles extending to higher altitudes. Campaign measurements focused on the Brazilian sector and included ground-based optical, radar, digisonde, and GPS measurements at a number of fixed and temporary sites. Related data on convection and plasma bubble structures were also collected by GOES 12 and the GUVI instrument aboard the TIMED satellite. Initial results of our analyses of …

The Effectiveness Of Institutional Intervention At Minimizing Demographic Inertia And Improving The Representation Of Women Faculty In Higher Education, Amanda V. Bakian

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

Across all science and engineering disciplines, women currently receive 46% of the doctoral degrees granted annually. Despite gains in doctoral degrees earned by women over the past 30 years, they remain under-represented among full time tenured /tenure-track science and engineering faculty compared to their presence among degree recipients. The inequality gap is widest among full professors at 4 year research universities where women account for a mere 16% of all S&E full time full professors. Multiple hypothesis have been proposed to account for women's under-representation relative to men including those based on human capital/economic theory, feminist theory, innate biological gender …

Random Motion And The Diffusion Of Brine Shrimp: A Project Based Learning Unit, Rebecca Atkins

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

Over the years, there have been several trends, philosophies, and ideas about how mathematics should be taught. These have included progressive movements, essentialist movements, drill and practice, teacher-centered methodologies, student-centered methodologies, and others. However, despite these various instructional trends, research has found that mathematics teachers have basically taught the same way for years, with little or no variation with respect to the changing trends (Ward, 2001). For many students, the traditional teaching method employed in their mathematics classes is typically centered on the teacher and includes lecture in which the teacher provides the necessary definitions and notations and does several …

Using Real-World Data As A Basis For Problem-Based Learning: Investigating Preservation Biases Of Fish In Fossil Butte National Monument, Blair Larsen

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

This project examined the design and development of an online problem-based learning module to teach earth-system science to K-12 educators. The module revolved around identifying earth sphere (lithosphere, hydrosphere, biosphere and atmosphere) interactions needed to produce mass fish mortality layers found in the Green River Formation at Fossil Butte National Monument. Students investigated the unique earth sphere combinations needed to produce mass fish mortality layers, reflected on the formation of such deposits, and examined the impact of these earth spheres on the earth system. As a supplement to the course, the students also analyzed data on fossils collected from a …

Investigations Into Mapping Lava Flows In The Snake River Plain, Idaho, Vinita Ruth Hobson-Broko

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

The origin of the Snake River plain continues to be debated, but the plume model is most popular at the current time. Some theories, such as meteorite impact, have been excluded, but the remaining theories require more scrutiny.

Various methods of examining phenomena in the Snake River Plain were employed. Unsupervised classification of Landsat ETM data indicates that spectra can be used to differentiate between flows. However, photographs of flows at Craters of the Moon National Monument show wide variations in texture and color within a single flow. Vegetation grows preferentially on the smoother pahoehoe slabs and significantly impacting the …

Teaching Probability Through Use Of An Applet, Melissa Gregory Jackson

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

The use of technology in the classroom is an ongoing debate by educators. Many teachers consider it to be a valuable teaching tool. Despite the many advantages, there are also drawbacks in using technology. A Java applet is a particular kind of multimedia technology proven to be useful in education. Because of students' struggles with learning basic probability in Statistics 1040, I have created a probability applet to reinforce the concept of probability. The applet was tested with two Statistics 1040 classes. The majority of students agreed that they learned more about probability from using the applet. Several of the …

Electrostatic Discharge In Spacecraft Materials, Jennifer Roth, Jr Dennison, Ryan C. Hoffman, David Peak

Senior Theses and Projects

Understanding the characteristics of electron beam bombardment that induce electrostatic discharge (ESD) of insulating materials is crucial to constructing an electrically stable spacecraft. A measurement system has been designed to determine the beam energy and charge flux densities at which typical spacecraft materials intended for the James Webb Space Telescope (JWST) undergo ESD. Because discharge events occur over time intervals ranging from nanoseconds to minutes, multiple detection methods were employed as charge was accumulated on a sample surface; these methods included monitoring of sample current and optical emissions from the sample surface. Each sample was also examined with optical microscopy …

The Pliocene/Pleistocene Evolution Of The Western Snake River Plain Near Grand View Idaho, Meagan R. Deraps

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

The Western Snake River Plain provides us with a unique opportunity to study the evolution of basaltic volcanism. In addition to studying the horizontal variation at the surface of the plain, erosion by the Snake River also allows the study of the vertical variation. With the aid of a USGS EDMAP grant we mapped the Dorsey Butte quadrangle and southern half of the Little Joe Butte quadrangle at a scale of 1 :24,000. The quadrangles are located within both the Ada and Elmore counties of southwestern Idaho, approximately 30 km west of Mountain Home and 2 km north of Grand …

Carbohydrate Derivatives In Antibiotics Research, Yi Liang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In this study, we investigated the potential applications of carbohydrates in the development of new antibiotics. To tackle the problem of multidrug-resistant variants of M. tuberculosis (MDR-TB), we investigated the biosynthesis pathways of trehalose, which has contributed to significant drug resistance. Some new methods were developed for the synthesis of potential inhibitors (6-azido-trehalose and 6,6'-diazido-trehalose) that have been designed to imitate the intermediate molecule (trehalose 6-phosphate, TPP) of OtsA-OtsB pathway. At the same time, some new antibacterial agents based on trehalose have been synthesized. Members of the 1,2,3-triazole family have shown interesting biological properties. Steroid derivatives have been developed in …

Detecting Organic Molecules On The Surface Of Inorganic Dust Particles Using Aerosol Mass Spectrometry, Sileola B. Akinsiku

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Detection of organic molecules present on the surface of dust particles is important in homeland security, agriculture, and several other applications. The research presented reports the ability of the aerosol mass spectrometer (AMS) to detect molecules on the surface of dust particles without detecting the particle core.

Experiments were carried out to detect semi-volatile organic compounds adsorbed onto the surface of particulates without interference from the dust particle core. Methyl salicylate, oleic acid, and organophosphorus pesticides such as Malathion were detected on the surface of particles representative of dust-type materials. Zeolite powders were used as aerosol support, representative of a …

Testing And Estimation For Functional Data With Applications To Magnetometer Records, Inga Maslova

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The functional linear model, Y_n = ψX_n + ε_n, with functional response and explanatory variables is considered. A simple test of the nullity of ψ based on the principal component decomposition is proposed. The test statistic has asymptotic chi-squared distribution, which is also an excellent approximation in finite samples. The methodology is applied to data from terrestrial magnetic observatories.

In recent years, the interaction of the auroral substorms with the equatorial and mid-latitude currents has been the subject of extensive research. We introduce a new statistical technique that allows us to test at a specified …

Covert Botnet Implementation And Defense Against Covert Botnets, Lokesh Babu Ramesh Babu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The advent of the Internet and its benevolent use has benefited mankind in private and business use alike. However, like any other technology, the Internet is often used for malevolent purposes. One such malevolent purpose is to attack computers using botnets. Botnets are stealthy, and the victims are typically unaware of the malicious activities and the resultant havoc they can cause. Computer security experts seek to combat the botnet menace. However, attackers come up with new botnet designs that exploit the weaknesses in existing defense mechanisms and, thus, continue to evade detection.

Therefore, it is necessary to analyze the weaknesses …

Analysis Of Total Electron Content (Tec) Variations In The Low- And Middle-Latitude Ionosphere, Ja Soon Shim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Detailed study of the spatial correlations of day-to-day ionospheric TEC variations on a global scale was performed for four 30-day-long periods in 2004 (January, March/April, June/July, September/October) using observations from more than 1000 ground-based GPS receivers. In order to obtain the spatial correlations, initially, the day-to-day variability was calculated by first mapping the observed slant TEC values for each 5-minute GPS ground receiver-satellite pair to the vertical and then differencing it with its corresponding value from the previous day. This resulted in more than 150 million values of day-to-day change in TEC (delta TEC). Next, statistics were performed on the …

Synthetic Studies Of Laulimalide Analogues, Ian Addison Mcalexander

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Chapter 1 provides some background information on the disease area of cancer and current modes of treatment. Chemotherapy treatment is discussed with a focus on the major cellular targets for these drugs: DNA and microtubules. For each target, classes of active compounds are described along with their mode of action. The microtubule stabilizing agent laulimalide is introduced and a case is made for analogue synthesis.

Chapter 2 describes our first generation efforts toward synthesis of des-methyl laulimalide. The target compound is divided into a northern and southern fragment with the synthesis of each fragment described. The preparation of landmark intermediates …

A Comparative Study Of The Structural Features And Kinetic Properties Of The Mofe And Vfe Proteins From Azotobacter Vinelandii, Miguel Alejandro Pabon Sanclemente

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Biological nitrogen fixation is accomplished in the bacterium Azotobacter vinelandii by means of three metalloenzymes: The molybdenum, vanadium, and iron-only nitrogenase. The knowledge regarding biological nitrogen fixation has come from studies on the Mo-dependent reaction. However, the V- and Fe-only-dependent reduction of nitrogen remains largely unknown.

By using homology modeling techniques, the protein folds that contain the metal cluster active sites for the V- and Fe-only nitrogenases were constructed. The models uncovered similarities and differences existing among the nitrogenases regarding the identity of the amino acid residues lining pivotal structural features for the correct functioning of the proteins. These differences, …

Novel Growth Of Ingaas/Gaas Nanostructures By Molecular Beam Epitaxy, Dong Jun Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This dissertation presents an extensive study of the epitaxial growth mechanism by a novel growth method. This novel growth method was developed at Utah State University and is a modification of the Stranski-Krastanov (S-K) growth mode. Our new growth method consists of a two-step process, low temperature growth and high temperature annealing. During low temperature growth, diffusion is minimized, resulting in the deposition of a pseudomorphic epilayer. During high temperature annealing, diffusion is induced from the pseudomorphic epilayer, resulting in the transformation of the epilayer into nanostructures. Benefits of this novel growth method are a significantly smaller segregation and suppressed …

Sonication Assisted Synthesis Of Oligomannosides, Christabel Tomla Tanifum

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Oligomannosides prevalently exist as cell surface antigens. They play important roles in diseases such as viral infection and cancer, and they have been shown to be useful as candidates for vaccines. HIV, one of the most devastating modern diseases, has a high content of mannose sugars on its envelope glycoprotein gp120. Oligomannosides of the HIV virus, also called Man9, which are found on the glycoprotein gp120, have been shown to play a protective role for the HIV virus, shielding highly conserved protein domains of gp120 from proteolytic attacks. Thus gp120 plays an important role in HIV infection of cells, being …

Fluvial Systems Tied Together Through A Common Base Level: The Geomorphic Response Of The Dirty Devil River, North Wash Creek, And The Colorado River To The Rapid Base Level Drop Of Lake Powell, Adam L. Majeski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fluvial adjustment to base level change has its roots in the fundamental concepts of geomorphology. This thesis explores the rate of erosion and sedimentation on the Colorado and Dirty Devil rivers and North Wash Creek under the current base level changes related to the drawdown conditions of Lake Powell. Through cross section and long profile resurveys, the current state of each system is captured and added to the historic record of sedimentation in Lake Powell. All three systems are generally forming narrow and deep incised channels driven by the rapid rate of base level fall. Cross sections that deviate from …

Symmetry Analysis Of General Rank-3 Pfaffian Systems In Five Variables, Francesco Strazzullo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In this dissertation we applied geometric methods to study underdetermined second order scalar ordinary differential equations (called general Monge equations), nonlinear involutive systems of two scalar partial differential equations in two independent variables and one unknown and non-Monge-Ampere Goursat parabolic scalar PDE in the plane. These particular kinds of differential equations are related to general rank-3 Pfaffian systems in five variables. Cartan studied these objects in his 1910 paper. In this work Cartan provided normal forms only for some general rank-3 Pfaffian systems with 14-, 7-, and 6-dimensional symmetry algebra.

In this dissertation we provided normal forms of all general …

On The Applicability Of Genetic Algorithms To Fast Solar Spectropolarimetric Inversions For Vector Magnetography, Brian J. Harker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The measurement of vector magnetic fields on the sun is one of the most important diagnostic tools for characterizing solar activity. The ubiquitous solar wind is guided into interplanetary space by open magnetic field lines in the upper solar atmosphere. Highly-energetic solar flares and Coronal Mass Ejections (CMEs) are triggered in lower layers of the solar atmosphere by the driving forces at the visible ``surface'' of the sun, the photosphere. The driving forces there tangle and interweave the vector magnetic fields, ultimately leading to an unstable field topology with large excess magnetic energy, and this excess energy is suddenly and …

Rayleigh-Lidar Observations Of Mesospheric Gravity Wave Activity Above Logan, Utah, Durga N. Kafle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A Rayleigh-scatter lidar operated from Utah State University (41.7°N, 111.8°W) for a period spanning 11 years ― 1993 through 2004. Of the 900 nights observed, data on 150 extended to 90 km or above. They were the ones used in these studies related to atmospheric gravity waves (AGWs) between 45 and 90 km. This is the first study of AGWs with an extensive data set that spans the whole mesosphere. Using the temperature and temperature gradient profiles, we produced a climatology of the Brunt-Väisälä (buoyancy) angular frequency squared, N² (rad/s)². The minimum and maximum values of N …