The migrations upstream of pre-spawned adult steelhead (Oncorhynchus mykiss) and
downstream of post-spawned steelhead (referred to as "kelts") can geographically and
temporally overlap in the Snake River, leading to management challenges for populations
listed under the Endangered Species Act (ESA). This thesis describes the development and
application of a method...
Sexual maturation and sex differentiation comprise facets of a
common theme: reproduction. The endocrine system regulates many
of the critical physiological processes necessary for reproduction and
offers a framework within which technologies can be developed for
controlling sexual maturation and sex differentiation. The studies
described in this thesis were undertaken...
Environmental factors such as chemical contamination can have immunomodulatory effects on the immune response of fish and may be contributing to the decline in salmonid populations by augmenting disease susceptibility. Xenobiotics can interfere with the immune system at several levels of complexity, and different immune cells and processes have variable...
The environment under which fish are maintained as broodstock before
reproduction is often stressful; however, the impact of stress on broodstock and gamete
quality is not well known. We investigated the effects of stress over the final stages (i.e.
the 3 months preceding ovulation) of sexual maturation of female rainbow...
Pacific lampreys (Lampetra tridentata) have declined in abundance in the Columbia River Basin. Although, the reasons for the decline are unclear, we suggest that development of hydroelectric dams and habitat alterations in tributaries as the main causes. The available knowledge of life history of Pacific lampreys and status from dam...
Sex differentiation in fish is a labile process that allows sex inversion in several species. The inherent capacity of fish germ cells to differentiate into oocytes or spermatocytes constitutes a key factor allowing for functional sex inversion. This thesis set out to determine the mechanism involved in steroid-induced sex differentiation...
Freshwater cyanobacterial blooms are a nuisance and health threat in the Pacific Northwest. The accepted methods of characterizing these blooms by microscopic cell counts cannot differentiate between toxic and non-toxic strains of the cyanobacterium Microcystis. Also, there is limited understanding of freshwater cyanophage that may control bloom dynamics. In order...
Alternative male phenotypes in salmonine fishes arise from individuals that mature as either larger and older anadromous marine-migrants or as smaller and younger freshwater residents. Variability in age and size of males at maturity is hypothesized to be preceded by early differences in growth in size and lipid storage. Water...
Early embryo development is dependent on maternally derived RNA and protein synthesized during oogenesis. In the bovine embryo this dependence lasts until the 8-16 cell stage, at which time embryonic transcripts become essential for continued development. One proposed mechanism for this transition from maternal to zygotic control of development (maternal...
While there are many more species of reptiles in the tropics than in temperate
latitudes, relatively little is known about the natural history of tropical species of
snakes. Even basic information, such as reproductive ecology and behavior, is lacking. Patterns of reproduction in tropical species differ from patterns in temperate...
The purpose of this work was to determine if environmentally-relevant concentrations of chlorpyrifos and copper, two commonly detected chemicals in Western surface waters, can negatively impact the biological health of salmonids. Both compounds are highly neurotoxic to fish, but each with distinct biological target sites and mechanisms of action. We...
Chinook salmon are the largest of any of the salmon in Oregon. Mature fish range from less than 2 pounds to more than 70 pounds. In the late 1800s, chinook salmon were almost the only species taken for canning in the Columbia River, with production peaking at 43 million pounds...
Coastal cutthroat trout is one of three cutthroat subspecies found in Oregon. The coastal subspecies, which is closely related to steelhead/rainbow trout and Pacific salmon, displays the most diverse and flexible life history of any of the Oregon salmonids. Coastal cutthroat can be found in streams and rivers from the...
The cultural and ecological values of Pacific lamprey (Lampetra tridentata) have not been understood by Euro-Americans and thus their great decline has almost gone unnoticed except by Native Americans, who elevated the issue and initiated research to restore its populations, at least in the Columbia Basin. They regard Pacific lamprey...
Anglers and naturelovers prize steelhead trout for their mystique and power. Oregon has two subspecies of steelhead (so-called because of the metallic appearance of maturing adults) or rainbow trout: a coastal form and an inland form.
I conducted field studies to determine the effect of insect herbivory and
intraspecific plant competition on ragwort Senecio jacobaea. The objectives were to
determine the patterns and causes in the distribution of the ragwort flea beetle
Longitarsus jacobaeae foraging among varying densities of ragwort, to measure the
behavioral and numerical...
Pheromones are chemical cues produced by organisms that affect the behavior and/or physiology of conspecifics. The orchestration of reproductive behaviors in many animals depends on the expression of sex pheromones. In insects, intraspecific variation in sex pheromone expression is commonly observed and often influences social interactions between individuals. To what...
An analytical method for predicting life-cycle maintainability labor costs is developed. The purpose of the analytical method is to allow the evaluation of products, based on life-cycle labor cost, early in the design process. The Boeing 737-300/400/500 Bleed Air Control System is used as a test model, and the results...
BoGL is a programming language created for the purpose of computer science education that is specific to the domain of board games. Although there is a language grammar and an existing implementation that is currently used by students, a complete and formal language standard does not yet exist. In the...
A technique that uses hypotonic lysis of erythrocytes was optimized for the purification of leukocytes from the peripheral blood and anterior kidney (pronephros) of rainbow trout Oncorhynchus mykiss. Comparisons of initial blood dilution (1:2, 1:4, and 1:6) and the time of exposure to hypotonic conditions (10, 20, and 40 s)...
Twenty-two steelhead trout (Salmo gairdneri) containing coded wire tags (CWT's) were captured in gillnets fished by the Oshoro-Maru in the Gulf of Alaska and along 180 during 1982-85. These fish originated from North American streams and hatcheries in British Columbia, Idaho, and Washington. One fish was age 0.1, 16 were...
The goal of this project was to develop and test non-herbicidal techniques that remove nonnative plant or weed seeds from the top 2 inches of the soil. The Nature Conservancy (TNC) is currently restoring prairies in the Willamette Valley. Some areas of the Pacific Northwest have already seen loss of...
The history of a software project plays a vital role in the software development process. Version control systems enable users of a software repository to look at the evolution of the source code, and see the changes that led to newer versions. Currently, version control systems provide commands that can...
The western purple martin (Progne subis arboricola) is a species of conservation concern throughout the Pacific Northwest. In western Oregon, the purple martin nests in three major ecosystem types: inland open-water, coastal, and upland forest. The availability of suitable breeding habitat is a major limiting factor for western purple martin...
This thesis examines the postmodern confrontation of representation throughout the oeuvre of Martin McDonagh. I particularly look to his later body of work, which directly and self-reflexively confronts issues of artistic representation & masculinity, in order to gain a more nuanced understanding of his earliest and most controversial plays. In...
Research on grief has been studied for nearly a century to understand its many facets, expressiveness, and timing. In the field of counseling, many changes in theories, models, and the lenses through which loss is responded to have been accomplished. However, one constant in the U.S. culture is that definitions...
Pseudomonas aeruginosa is a ubiquitous gram-negative bacterium that is capable of causing infections in people who are immune compromised. The bacterium can live in a variety of environments due to the variety of virulence factors it can produce. It is well adapted to living in iron-stringent conditions because it can...
When iron levels are low, the opportunistic pathogen Pseudomonas aeruginosa secretes the high-affinity iron-binding siderophore pyoverdine. The cognate ferripyoverdine receptor, FpvA, has gained attention as the most divergent gene in the organism’s genome, showing substantial evidence of positive selection. S-type pyocins, bacteriocins with specificity to Pseudomonads, enter cells through FpvA...
High nitrogen (N) accumulation in terrestrial ecosystems can shift patterns of nutrient limitation and deficiency beyond N toward other nutrients, most notably phosphorus (P) and base cations (calcium [Ca], magnesium [Mg], and potassium [K]). We examined how naturally high N accumulation from a legacy of symbiotic N fixation shaped P...
Cooperative behaviors in bacteria are increasingly appreciated for their relevance to microbial ecology and utility as model systems for social evolution. One example is the secretion of siderophores, a structurally diverse group of compounds that chelate extracellular iron. Siderophore production is considered cooperative because the benefits can be shared with...
An interdisciplinary study into the theory of design decisions has yielded a model for tracking design changes in hardware/software systems, but it still needs to be applied to a larger system to test its efficiency at tracking important data. This thesis creates an implementation of PLEXIL, a language in development...
Correctness and efficiency are important properties of programs. However, to support maintenance and debugging, the programs should also be understandable. Program explanations also play a vital role in educational settings, enhancing the understanding of programs among students.
Proof trees provide a sound basis for generating dynamic explanations of programs. But...
Research was conducted on the Keating rangelands in north-eastern Oregon to determine the food habits of deer and cattle and
similarity of their diets, and to estimate deer and cattle months of
grazing on both a quantitative and nutritional basis. Data were
collected during the winters of 1978-1979, 1979-1980 and...
We present the evolution of a reasoning system for inferring dimension information in
spreadsheets. The three papers included in this thesis show how the initial system can be
used to check the consistency of spreadsheet formulas and thus is able to detect errors in
spreadsheets, and the evolution to a...
The study of variational typing originated from the problem of type inference for variational programs, which encode numerous different but related plain programs. In this dissertation, I present a sound and complete type inference algorithm for inferring types of all plain programs encoded in variational programs. The proposed algorithm runs...
Spreadsheets are a pervasive technology throughout personal and industrial use. Often times, the user is not the author, contributing to a lack of understanding of the purpose and functionality of a spreadsheet. Furthermore, the lack of understanding is a major reason for mistakes in the use and maintenance of spreadsheets....
The use of board games for teaching introductory computer science is a promising recent avenue of research. The goal is to introduce computing concepts through their use in the implementations of simple games, thereby keeping students engaged through their learning process. However, there is a gap between students' algorithmic descriptions...
Pseudomonas aeruginosa is an opportunistic human pathogen that infects immunocompromised individuals such as those suffering from burns or the genetic disorder cystic fibrosis. This organism utilizes a cell-cell communication mechanism known as quorum sensing (QS) to coordinate virulence gene expression and biofilm formation. It has three interconnected QS systems, namely...
Spreadsheets are among the most widely used end-user programming systems. Unfortunately, there is a high incidence of errors in end-user spreadsheets, and some of these errors have high impact. In this dissertation, we describe techniques we have developed to help end users develop safer spreadsheets. As part of our research,...
The code reuse problem is a common software engineering problem in scientific computing. As a prevailing programming language in many scientific fields, Fortran does not provide support to address this problem. One particular reason is that Fortran lacks the support for generic programming. By applying program-generation techniques, we developed two...
Social behavior leading to the production of common goods is prone to exploitation. One such behavior in Pseudomonas aeruginosa is quorum sensing (QS), by which the bacteria produce signals to regulate extracellular common goods. Exploitation comes in the form of cheaters which have a mutation in the central quorum sensing...
Landscape models for elk distribution developed at Starkey Experimental Forest and Range from 1993-1995 were tested on another landscape during 2003-2005 at Sled Springs Wildlife Demonstration Area. Using location data obtained from 23 wild elk captured and fitted with GPS telemetry collars, 8 spatial resource selection function models representing 8...