The platinum-group metals have been the subject of considerable discussion in the news media over the past few months, particularly because of their projected use as catalysts in automobile engines. Metals Week of August 27 shows that platinum commands a price of $176.00 per ounce, as compared to $150.00 per...
The recent increase in awareness of the seismic hazards in Oregon has led to a concern regarding the safety of Oregon State University buildings. While the decision has been made to initiate the seismic rehabilitation of campus facilities, the question of which buildings pose the greatest hazards, and are therefore...
Several uranium anomalies, with concentrations of U₃0₈ that
average below 0.003 percent and reach maximums of 0.069 percent,
are associated with black, fossiliferous, pyritic parts of the Ordovician
Ledbetter Slate in northern Stevens County, Washington. The most
uraniferous parts of the slate occur in small (average of 5 by 30...
Steven Universe, a relatively new show from Cartoon Network, explores an unexpectedly complex understanding of gender through their main protagonists. Utilizing Judith Butler’s work on gender performativity and doing gender, as well as Daniel Dennett’s conception of the self as a theorist’s fiction, and Alexander Weheliye’s understanding of power and...
Increased competition brought about by trade liberalization has raised the stakes
for improving productivity in U.S. and Canadian food processing. A key element of
productivity growth is technological change, which in turn results from R&D investment.
The present study employs an econometric model to assess rates of technological change
and...
Under the reauthorized Magnuson-Stevens Act (MSRA), US fisheries management councils must specify an annual catch limit (ACL) for each managed species and institute accountability measures (AMs) to ensure that actual harvest will not cause the stock to be overfished. While the details of implementation are still being developed, a set...
This thesis is an observational study that examines relationships between disturbance, forest stand development, and big huckleberry (Vaccinium membranaceum) fruit productivity and growth by combining ecological methods with the traditional ecological knowledge of Warm Springs ceremonial huckleberry pickers. Shrub fields of fruiting big huckleberry develop in early seral subalpine environments...
Following thermal neutron induced fission, supervised machine learning and temporal gamma-ray spectroscopy methods were used to identify differences in the delayed gamma-ray spectra of Pu-239 and U-235. The temporal gamma-ray spectroscopy method takes advantage of the time-dependent decay of fission products. Employing Spearman's rank-order correlation coefficient and without prior knowledge...
Radiological emergency plans ensure that protective actions can and will be taken in the event of an accident. Principle protective actions for the early phase of an emergency are evacuation and sheltering-in-place. While evacuations are generally safe, there are deterministic, long-term health consequences from prolonged displacement that outweigh the stochastic...
The performance of pull factors for total retail sales in Oregon's
nonmetropolitan counties during the economic cycle of boom, bust, and recovery
of the early 1980s is examined for geographic patterns. One regional pattern and
several county patterns are identified and discussed. Counties having the highest
and lowest pull factors,...
The goal of this dissertation was to improve our understanding of the physiology and life-history of invasive plants and of the mechanisms underlying life-history trade-offs. I compared invasive and noninvasive species of Rubus (blackberry) that grow together in the Pacific Northwest. Three hypotheses were investigated: (1) Invasive Rubus have higher...
In response to the events on September the Eleventh, various media attempted to make sense of the seemingly radical altered political landscape. Comic books, though traditionally framed as low brow pulp, were no exception. This thesis is a work of rhetorical criticism. It applies Walter Fisher's Narrative Paradigm to a...
The Regional Vegetation Management Model (RVMM) predicts the effects of associated vegetation on the growth and yield of young Douglas-fir (age [less than or equal to] 20 years) in the Pacific Northwest, and is a 'front-end' growth model for existing rotation-age growth models. Objectives of this thesis are to: (a)...
While many geographers believe that the regional
concept is central to geographic study, no definitive regional
scheme exists. The criteria considered in each regional study
will relate to a stated objective or study. Ecological
regionalization is a major contribution by geographers to
environmental studies. By examining spatial patterns of factors...
Breast cancer is the most common cancer among women as it accounts for about 25% of all female cancer cases. Studies have shown that early detection of breast cancer increases the chances of a positive prognosis amongst patients therefore it is crucial to provide accurate diagnosis tools in routine exams....
Thin foil samples of special nuclear materials (SNMs) were irradiated for 60s using a Mark TRIGA II reactor, and their associated gamma emissions were recorded with a count time of 60s following irradiation. A rapid pneumatic transfer system was used to irradiate the samples in front of beam port #4....
Natural uranium samples were irradiated in-core for 7 seconds using the pneumatic rabbit system within the TRIGA Mark II Reactor at Oregon State University, and then used to generate a gamma-ray spectrum with a high purity germanium (HPGe) detector. The irradiated sample was simulated in Monte Carlo N-Particle (MCNP), a...
Two experiments were conducted on the invasive plant species Potentilla recta in northeastern Oregon to investigate both biological and ecological characteristics of the species. Growth analysis was conducted on the plant at three sites over a period of two years (2002 and 2003). Relative growth rate (RGR) was calculated for...
Plant form is a compromise between resource gathering, reproduction and
the tolerance to physical demands of the abiotic and biotic environment. In
an agricultural field in addition to the natural factors causing stress, humans
also introduce physical and mechanical stresses, and chemical pesticides
into the environment. Many of these factors...
This thesis consists of four chapters. Literature is
reviewed in Chapter 1. Chapter 2 describes an addition
series experiment to determine the influence of species
density and proportion on vegetative and reproductive yield
of spring wheat and Lolium multiflorum. Chapter 3 consists
of a growth analysis experiment to determine whether...
Oregon land use specialists believe that the present
definitions of farm and forest land in the state planning
goals are too broad. This results in poor quality resource
lands being as strongly protected as those of top quality.
With persistent growth pressure on rural lands, a means to
distinguish among...
Models of weed communities aid in the development of
weed management strategies and elucidate the processes
and mechanisms that regulate plant populations and
communities. A conceptual weed community model was
developed to organize key regulatory life-history
processes. Specific investigations focused on the
processes of plant growth and competition, and
relationships...
Neutron radiography has been used to study cementitious materials. This thesis studies the impact of heavy water on both the rate of hydration and neutron radiography. The neutron attenuation coefficients of light and heavy water were measured. Cement pastes were made with both heavy and light water. The attenuation coefficients...
A new method for delayed gamma-ray spectrometry to quantify the relative content of fissile material is developed and demonstrated to support international efforts in bolstering non-destructive assay capabilities. Previous traditional delayed gamma-ray spectrometry techniques rely upon nuclear data that often carry very high uncertainty. The new method removes the requirement...
The neutron flux-energy spectral characterization of a Thermo Fisher MP320 deuterium-tritium neutron generator was performed for two shielding configurations, one with substantial moderator between the source and the sample and one without such moderator. The STAYSL PNNL spectral adjustment code was utilized in conjunction with MCNP modelled reference spectra and...
Breast cancer is the leading cancer in women with an estimated 13% of women in the United States developing a form of invasive breast cancer in her lifetime. The survival rate is estimated to be 85%, but the American Cancer Society estimates that early detection of breast cancer in the...
Agroforestry is a traditional farming practice in American Samoa that has helped to sustain the livelihood of the native population for centuries. These once self-sufficient islands have become economically dependent on U.S monies and other external resources during the past century. Dependency has caused a shift in the carrying capacity...
Salmonberry (Rubus spectabilis) and thimbleberry
(Rubus parviflorus) are clonal shrub species common to
reforestation sites in the Oregon Coast Range. These
species have economic importance, because they reduce
conifer seedling growth and survival. A population modeling
approach was used to facilitate study of the biology of
these species and to...
This study examines the relationships among variables influencing
solar access in the Portland-Vancouver Metropolitan Area. The
analysis is based on a random sample of approximately 400 single-family
homes in 21 local jurisdictions outside the city limits of Portland.
Relationships between percentage of available sunlight and selected
variables were examined by...
Allometric equations are useful tools for predicting tree biomass when direct measurements are impractical. Any factor affecting plant growth can be a significant variable in allometric equations. Density and species proportion are spatial variables that influence tree growth and should be considered when developing allometric equations. This consideration is especially...
Improving vegetation management decisions in Pacific Northwest forests requires a better understanding of the interactions between
planted conifers and associated vegetation. A practical index of interspecific competition, and quantitative models predicting conifer performance from such an index are particularly needed. To meet this
need, neighborhood models of interspecific competition were...
Sitka alder (Alnus sinuata (Regel) Rydb.) dominates many lodgepole pine (Pinus contorta ssp. latifolia Dougl.) sites following clearcutting in the Montane Spruce zone of the southern interior of British Columbia. The objectives of this study were to examine the effects of the sitka alder-dominated shrub community on the performance of...
Competitive interactions between Douglas-fir seedlings (Pseudotsuga menziesii), and seedlings of a nitrogen-fixing hardwood
associate, red alder (Alnus rubra), were investigated in an addition series experiment. The primary objective of the research was to identify and quantify key processes underlying intra- and interspecific competitive interactions of Douglas-fir and red alder seedlings....
I investigated the population dynamics of fireweed (Epilobium angustfolium), foxglove (Digitalis purpurea) , and woodland groundsel (Senecio sylvaticus) to understand
their colonization, persistence, and extirpation in Pacific Northwest Douglas-fir forests. Factors affecting the species' frequency and abundance in forest communities were evaluated. Their population dynamics were modeled and field experiments...
The response to various levels of stand density by natural Douglas-fir regeneration, shrub and sprouting hardwood species was studied in the mixed-evergreen-forests of southwest Oregon. Partial-cut old growth (harvested 22-31 years prior) and thinned evenaged (harvested 9-17 years prior) stand types were used as surrogates for intentionally managed uneven-aged stand...
Two tributaries of the south fork of the Burnt River, near Unity Oregon were studied
during the summers of 2000 and 2001 to determine water heating and cooling
patterns. Hourly temperature data were recorded for air, water, and soil parameters
at four elevations 150m apart on Barney and Stevens Creeks....
Understanding how N availability influences base cation stores is critical for long-term ecosystem sustainability. Indices of nitrogen (N) availability and the distribution of nutrients in plant biomass, soil, and soil water were examined across ten young, unpolluted Douglas-fir (Pseudotsuga menziesii) stands in the Oregon Coast Range spanning a three-fold soil...
Habitat restoration projects are vital for recovering ecosystems, but they can be expensive. One way to help justify the price tag is to value the economic benefits provided by the restored habitat. The issue is that many ecosystem services and the flow of benefits they produce are complex, requiring careful...
Nitric oxide (NO) is a signaling molecule that regulates blood pressure and vascular tone. Humans produce NO by endothelial nitric oxide synthase (eNOS), which is impaired in patients with cardiovascular disease leading to increased blood pressure, endothelial dysfunction, and an increased risk of adverse cardiovascular outcomes. Maintaining optimal levels of...
Differences in primary production and periphyton and macroinvertebrate
biomass between pairs of constrained (valley floor width of less than twice the active
channel width) and unconstrained reaches were investigated in Elk River and four
tributaries in southwest Oregon. In August 1991, macroinvertebrates were sampled
from individual cobbles, and rocks were...
The defining feature of our planet are the oceans, which make up 70% of the Earth’s surface. The importance of the ocean cannot be understated: 50% of oxygen originates from phytoplankton; heat is absorbed and redistributed by ocean currents; and hundreds of millions of people rely on the ocean for...
The onsite costs and benefits of conservation tillage in the
Camas Prairie Region of Northern Idaho were estimated. The evaluation
of these costs and benefits included a measurement of the
long-term effects of soil erosion on cropland productivity.
A model developed by Daniel Taylor (1982) was used as a base...
