Oregon White Oaks (Quercus garryana) were once abundant in the Willamette Valley, Oregon, but have drastically decreased because of fire suppression, agriculture, and human development. Oaks are an important ecosystem because they provide a diverse habitat for bird species that are insectivorous and/or cavity nesters. We studied the oak restoration...
The sagebrush ecosystem, home to numerous plant and animal species including big sagebrush (Artemisia tridentata) and the endemic greater sage-grouse (Centrocercus urophasianus), has endured fragmentation and degradation of both quantity and quality due to the cumulative and synergistic relationships between an abundance of individual disturbances including grazing, invasive annuals and...
Mammalian female reproduction requires preovulatory surges of gonadotropin-releasing hormone (GnRH) from neurons in the preoptic area (POA) of the hypothalamus, initiated by elevated estradiol (E₂). Rising E₂ activates a subset ofsexually dimorphic Kisspeptin neurons in the female, located in the anteroventralperiventricular nuclei (AVPV). Conversely, E₂ negative feedback is mediated by...
The sagebrush ecosystem, home to numerous plant and animal species including big sagebrush (Artemisia tridentata) and the endemic greater sage-grouse (Centrocercus urophasianus), has endured fragmentation and degradation of both quantity and quality due to the cumulative and synergistic relationships between an abundance of individual disturbances including grazing, invasive annuals and...
We developed an integration-based line detection algorithm. Existing line detection methods such as the Hough Transformation (HT) and its variants are insensitive to image noise. The reason is that HT finds lines by calculating the gradient of the image and assumes that the region where the gradient is the steepest...
In this paper I present the results of Monte Carlo simulations for a soft sphere fluid with a Weeks-Chandler-Anderson (WCA) pair potential. The results are compared to Soft Fundamental Measure Theory (SFMT) results obtained by our research group. One of the research group’s goals was to show that our SFMT...
When a star dies in a supernova, its constituent particles are torn apart and a gaseous cloud of atoms remains. These atoms may eventually condense again into large bodies such as planets and stars. There are three main theories as to how this happens: classical, kinetic, and non-local thermodynamic equilibrium...
This study examines climatological influences, particularly that of snowpack, on tree growth and stable carbon isotope discrimination (Δ¹³C) from ~1980 to 2013 at two sites located in the upper reaches of the McKenzie River watershed of the Oregon Cascade Mountains. We tested the use of Δ¹³C values from latewood, corroborated...
This research specifically examines the collective motion of populations of MDA-MB-231 breast cancer cells under the influence of a chemo-attractant gradient. Their motion is compared to the mathematical model of a persistent random walk, measuring the persistence bias of the cells from their autocorrelation function and applying to the mean...
Many biological processes are regulated by the presence and movement of cellular Ca²⁺ ions. The concentration of Ca²⁺ in a cellular environment is regulated by IP₃ sensitive channels that lie on the surface of a cell’s endoplasmic reticulum. Little is known about the macroscopic effects of intracellular Ca²⁺ activity, so...
Galápagos marine iguana population sizes have been declining since first contact with humans.This decline has historically been attributed mainly to predation by invasive species, but additional human-caused threats exist today. My thesis conducts an analysis of the present threats to the species and determines which are the most severe.Modern threats...
Carbon nanotubes are the subject of intense interest in virtually every field, from medicine to nano-scale electrical components. Multi-walled nanotubes exhibit a strong nonlinear response to high-field strength terahertz radiation. This research uses terahertz pulses with field strength exceeding 1 MV/cm generated by means of optical rectification utilizing a lithium...
Today, with countless study abroad programs available, students have the opportunity to travel and study all over the world. Those who are lucky enough to study abroad are able to embark on an international journey that will change their life forever. This thesis expands on what happens after returning home...
According to the World Health Organization’s (WHO) Tuberculosis Annual Report of 2014, from the 9 million cases worldwide, China has about 11% of these cases. Although the control of TB has improved over the years, China still has the second leading highest Tuberculosis epidemic in the world. Using literature reviews...
An experimental apparatus is modified to allow measurements of the Seebeck coefficient and resistivity to be taken simultaneously. This apparatus is designed for bulk and thin film samples between temperatures of 10 K and 300 K. The apparatus is constructed such that these simultaneous measurements do not interfere with each...
Fractal visual hashes have the potential to replace traditional hexadecimal hashes for SSH applications with the goal of increasing user recognition of identities of remote computers. Rather than rely on human users manually comparing two hexadecimal hashes as part of SSH's public-private key encryption process, users would compare fractal images...
This thesis looks at the third harmonic voltage response of a small incandescent lightbulb. The third harmonic voltage, or 3 omega (3ω) voltage, arises from applying a 1ω sinusoidal voltage across a resistive material. The 3ω voltage carries with it information about the thermal conductivity of the material. A lock-in-amplifier...
The current model for gamma ray bursts (GRBs) assumes that internal shocks are responsible for the emission of gamma-rays. Internal shocks occur when the fast expanding shell collides with the slowly expanding shells. The light curve of a GRB depends on the initial state and the expanding speed of the...
The scattering of optical rays by small spherical particles bears a strong resemblance to the
diffusion of fission neutrons in solid materials. This work explores the feasibility of
exploiting similarities between these two systems for the purposes of reactor component analysis, education, and outreach. After a brief overview of reactor-environment...
A method for determining bandgap energy using diffuse reflection is presented. The method uses bifurcated fiber optic cables to measure the diffuse reflection of diffusely reflective materials. The absorption spectrum is extrapolated from the diffuse reflection spectrum and used to determine the bandgap of powdered materials. The theory of nonspecular...
The synergetic interplay between the removal of saturated methyl esters and the addition of deoxygenated fatty acids on depressing the cloud point temperature of biodiesel was investigated in this study. Canola biodiesel was produced in batch as a standard with a cloud point of 1.37 +/- 6.3°C. Saturated methyl esters...
Pollination is a critical ecosystem function for sustaining biodiversity. However, pollinators and the services they provide are threatened by landscape-altering anthropogenic activities across the globe. Habitat loss and fragmentation, introduction of invasive species, chemical use, and urbanization have been shown to impact pollination. Pollinator foraging behavior is thought to be...
We construct the contact value approximation (CVA) for the pair distribution function,
g(²)(r₁, r₂), for an inhomogeneous hard sphere fluid. The CVA is an average of two radial
distribution functions, which each take as input the distance between the particles, |r₂ −r₁|,
and the average value of the radial distribution...