Large, alluvial rivers are naturally diverse, both in structural complexity and as drivers of landscape dynamics. Floodplains provide a mosaic of habitat types for aquatic, semi-aquatic, and terrestrial organisms and act as the framework for vital chemical processes to occur. In large part, this variety is due to the ability...
The global cryosphere, defined as the world’s ice and snow covered regions, is a crucial water source for society and ecosystem functions, as well as an important regulator of the earth’s energy budget. Melt from glaciers and seasonal snow cover provides water for more than a sixth of the world’s...
In the Colombian Amazon there has been a complex interplay of rebel groups’ control over land, drug trafficking, and absence of the Government of Colombia. Here, I use satellite remote sensing, ethnographic research and statistical models to provide insights into causal effect and causal mechanisms of land change and economic...
Effective forest governance is central to the efficient, sustainable, and equitable use of forest resources, yet challenges in assessing forest governance impede efforts to improve it. Contemporary forest governance involves decisions by multiple stakeholders across multiple sectors of economy and society, from local to global scales – making forest governance...
We live on an Urban Planet. The current unprecedented urbanization is accompanied by intensive land cover transition and demographic shifts from rural to urban livelihoods. Cities serve as cultural, economic, political centers that facilitate wealth creation and innovation of the society, sustaining human from multi-dimensions with large ecological footprints far...
Developing accurate predictive distribution models requires adequately representing relevant spatial and temporal scales, as these scales are ultimately reflective of the relationships between distributions and influential environmental conditions. In this research, we considered both spatial and temporal scale and the influence each has on predicting broad-scale distributions of two disparate...
The objective of this dissertation is to enhance the monitoring of forest ecosystems through the utilization of remotely sensed data to address the exigencies posed by the Anthropocene. On a global scale, rising temperatures and fluctuating precipitation patterns have strained forests and produced shifts in natural disturbance regimes. Additionally, the...
A need exists to develop a non-destructive testing technique that can identify
the formation and propagation of diagonal tension cracks in conventionally
steel reinforced concrete deck girder (RCDG) highway bridges in the State of
Oregon. Such a technique could be included into a structural health
monitoring (SHM) system installed on...
Grapes (e.g. Vitis vinifera L.) are one of the more important fruit crops from an economic standpoint with world market values over 550 million US dollars in 2007 and 2008, second to apples (United States Department of Agriculture). While a satisfactory level of ripeness is of primary concern, the quality...
Mule deer (Odocoileus hemionus hemionus) and Rocky Mountain elk (Cervus canadensis nelsoni; hereafter elk) populations in northeast Oregon have declined in the past 10 to 20 years. Concurrent with these declines, cougar (Puma concolor) populations have apparently increased, leading to speculation that predation by cougars may be responsible for declining...
Cavitation instabilities in elastic-plastic solids under spherically-symmetric and axisymmetric loadings were investigated using the finite element method. Both quasi-static and dynamic analyses were used to solve these problems. In the quasi-static analyses, we investigated a cavitation instability in elastic/perfectly-plastic, linear hardening elastic-plastic, power hardening elasticplastic, and constrained silver materials. Here,...
On September 12th 1960, just two months prior to one of the closest
Presidential elections in American history, John F. Kennedy faced the Houston
Ministerial Association and delivered a powerful speech on religion and
Americanism. The "religious issue" of the 1960 campaign drew immense interest
and trumped other issues pertinent...
Several solar energy models exist, but all models must balance: computational runtime, light complexity, and model output volume. These models span the spectrum of simplistic global solar energy equation sets to complex light ray-tracing models. Spatiotemporally inaccurate representations of solar energy may cause compounding simulation effects and introduce unknown modeling...
Given the vital role of forest ecosystems in landscape pattern and process, it is important to quantify the effects, feedbacks, and uncertainties associated with forest disturbance dynamics. In western North America, insects and wildfires are both native disturbances that have influenced forests for millennia, and both are projected to increase...
The validity of the widely used stochastic linearization
method for analysing the response of guyed towers to stochastic loads
is investigated. The governing equations of a guyed tower have two
main sources of nonlinearities, fluid-structure interaction and the
restoring force of the cables. In this study, two models are
considered....
Energy development is expanding rapidly across the western US. Negative effects have been documented for some wildlife, but consequences of development are unclear for other taxa, including raptors. We had the opportunity to examine effects of oil and natural gas development on two raptor species of conservation concern, ferruginous hawks...
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Patricia L. Kennedy
Energy development is expanding rapidly across the western US
Many climatic factors influence grape berry composition including nutrient status, water availability, biotic stress, sun exposure and temperature. Previous research examined the effects of many factors listed above and much progress has been made. It is often difficult, however, to separate effects that typically confound each other, such as sun...
The object of this research, project was to study how
different parameters effect the magnitude and frequency
composition of forces exerted on simulated heat exchange
tubes immersed in a cold fluidized bed. Two arrays of
tubes were assembled with the tubes mounted in an
equilateral triangular pitch pattern. The center...
The purpose of this study was to determine if a significant
difference in cognitive achievement and retention occurred when skeletal
system anatomy and terminology were presented utilizing either videotaped
presentations or a traditional laboratory procedure.
Fifty-three first semester nursing students enrolled in biology
(Bio. 160 anatomy and physiology) at Lethbridge...
Many pollination studies with honey bees have examined the effect of colony density on crop yield and yet overlook the effect of variation in the population size of these colonies. High colony density in northern highbush blueberry has been met with concerns from beekeepers who feel higher densities will intensify...
The rate of interaction of carbon dioxide with eight detached organic films commonly used as coatings for metal surfaces was examined.
The films studied were lacquers of several different formulations
including oleoresinous, phenolic, vinyl, alkyd, epoxy, and
hydrocarbon types. The sorption was measured on a McBain type
gravimetric adsorption balance...
The purpose of this study was to investigate the household tasks that
school-age children perform and the average amount of time spent performing
those tasks. The sample included 219 children in 135 families
taken from the Oregon sample of 210 families interviewed for the Northeast
Regional Research Project 113: "An...
One group of four adult White Leghorn male chickens was fed a
diet containing 7.3% linoleic acid and 32.4 mg/ kg of added vitamin E
(group IV) for 50 weeks which was designated as the positive control.
A second lot (group I) containing 14 males received the same level of...
Since 2007, electronic cigarette (e-cigarette) sales in the U.S. have surpassed those of tobacco cigarettes. This is due, in part, to manufacturer’s claims that they are a safer alternative to tobacco cigarettes. However, formaldehyde, acrolein, and diacetyl have been detected in e-cigarettes and public knowledge of e-cigarette composition and potential...
Childhood cancers are rare diseases that affect 188 children in Texas for every million born. Leukemia is the most common childhood cancer and accounts for roughly one third of childhood cancer cases. However, it is estimated that only 10% of childhood cancer cases can be explained by known risk factors....
The overarching objective of this study is to examine and compare the vulnerabilities of bridges combining effects of earthquake-induced ground shaking, ground failure (e.g., landslides and lateral spreading), and tsunami inundation. A parametric study is performed to understand the sensitivity of economic loss and traffic capacity with respect to the...
Groundwater overdraft in the Wilcox Groundwater Basin, as a consequence of increasing rates of agricultural groundwater withdrawal, has led to significant regional groundwater level decline and threatens to undermine the basin’s long-term water resource security. Updated characterization of the basin’s water resource conditions and agricultural water demand is critically important...
The climate and geologic conditions of the Pacific Northwest leaves its roads highly susceptible to rockfall hazards. Rockfalls often occur on steep slopes that experience heavy rainfall, groundwater seepage, or strong shaking from earthquakes. The unpredictable nature of these events often creates substantial problems for communities, transportation infrastructure, and the...
The Supreme Court Bar-the lawyers who argue before the US Supreme Court-has historically been an elite and exclusive group. This investigation examines the demographic make-up of the Supreme Court Bar in the Roberts Court and compares it to previous iterations of the Supreme Court Bar, as well as the national...
Boreal and temperate biomes host nearly half of the earth’s forested ecosystems. The temperate rainforests of the Pacific coast of North America constitute nearly half of all temperate rainforests on earth. Along the northern extent of this region, the perhumid and sub-polar rainforests of southeast and southcentral Alaska are among...
Collaborative decision-making is often promoted as a means to achieve socially acceptable and enduring solutions to natural resource management issues, and one that holds promise for resolving “wicked” problems. However, success rates for implementation of collaborative recommendations are unknown. This paper explores challenges to collaborative salmon fishery management in Prince...
In mining and mineral processing, compressive loading is often encountered
during the comminution of ore bearing minerals and in the wear resistant materials
used in the comminution circuit. A common thread joining many of the materials that
are primarily used under compressive loading is the presence of a high modulus...
In 2003 and 2004 vigor zones were delineated in two commercial vineyard
sites based on vine growth variation to assess fruit and wine phenolic chemistry. In
2004, the effects of shading on the accumulation of phenolic compounds were also
investigated. Model extractions were done from the shading experiment and the...
In granular or fibrous materials, in which the dimensions of the internal
structure can be of the same order of magnitude as major flaws or holes, classical
elasticity theory does not consistently provide accurate models of the large stress
gradients that may develop. With the incorporation of additional rotational degrees...
Aquatic insect population counts can be a good indicator of the health, or water quality, of rivers and streams. Stoneflies (Plecoptera) are particularly susceptible to pollution in streams. However, today’s current method for obtaining these population counts requires biologists to examine individual specimens under a microscope for identification to the...
Polymeric composites exhibit time-dependent behavior, which raises a concern
about their long term durability and leads to a viscoelastic study of these materials.
Linear viscoelastic analysis has been found to be inadequate because many polymers
exhibit nonlinear viscoelastic behavior. Classical laminate theory is commonly used in
the study of laminated...
Improvement of manufacturing productivity is dependent on the successful
automation of manufacturing processes, the success of which is based in turn upon
the availability of information which describes the state of manufacturing operations.
Acoustic Emission (AE) signals related to the cutting process and tool wear have
been recently applied to...
The research undertaken consisted of the study of three topics
affecting the performance of asphalt concrete mixtures, that is, mixing
moisture, oxidative aging and higher tire pressures and axle loads.
This thesis presents the findings of the research comprising these
three topics.
In the first study, the effects of mixing...
Cognitive impairment, or cognitive decline, a noticeable and measurable decline in cognitive abilities (e.g. memory and learning) that exceeds those attributed to normal aging, represents an early symptom of neurodegeneration and increased risk for progression to more severe dementias, such as Alzheimer's disease (AD). While the complex etiology of these...
In order to estimate wind turbine residL2;characteristics
in the presence of atmospheric turbulence, the important atmospheric
sources for the force excitations felt by the wind turbine system
must be identified and characterized. The goal of this research
is to develop the wind turbulence input model for horizontal axis
wind turbines....
Despite numerous techniques for measuring and estimating water depth, bathymetry in the nearshore zone is notoriously difficult to map. Dangerous sea states, noisy environmental conditions, and expensive survey operations, particularly in remote areas, contribute to the difficulties of obtaining data along the coast. Global datasets, derived mainly from satellite altimetry...
In this work we consider the dependence of solutions to a partial differential equations system on its data. The problem of interest is a coupled model of nonlinear flow and transport in porous media, with applications, e.g. to environmental modeling. The model of flow we consider is known as the...
Oregon Department of Transportation’s bridge no. 9743b is a multi-span, two-girder steel deck bridge connecting the busy interstates 5 and 205. Vertical cracks have been detected in the welded girder-to-crossbeam connections at the bents. Distortion-induced fatigue is suspected to be responsible for the cracking. Linear elastic beam analysis, 2-D and...
