The purpose of this study was to describe the leadership development process
of former student leaders at Snow College. More specifically, the study focused on
understanding how, when, and where leadership development took place in their
"lived experience" within the student government at Snow College (Van Manen,
1998). Examining the...
A plethora of land use policies are implemented at the local, state, and federal levels to influence the manner in which land is utilized. The distribution of the costs and benefits associated with implementing such land use policies always has been, and will continue to be, a source of contention....
Treating durable, second-growth or plantation-grown material with supplemental chemicals could improve durability while enhancing the uniformity of the products. To test this hypothesis, the effect of two candidate biocide treatments on the durability of teak, redwood, and western redcedar was assessed in a ground proximity field test established in Hawaii....
Descriptions of the fire regime in the Douglas-fir/western hemlock region of the Pacific Northwest traditionally have emphasized infrequent, predominantly stand-replacement fires and an associated linear pathway of stand development, where all stands proceed along a common pathway until reset by the next fire. Although such a description may apply in...
The purpose of this study is to examine the learning that occurs in Latina students
who enroll in learning communities designed for underprepared community college
students. The research question guiding this study is: What are the experiences of Latina
students enrolled in developmental learning community courses which have the greatest...
Successful ecosystem restoration requires an understanding of the ecological processes directing succession. One of the challenges in the semi-arid grasslands of western United States is replacement of native species by invasive annual grasses. Solutions to this problem require identifying and manipulating ecological processes that direct succession to favor desired vegetation....
The development of microfluidic devices for heavy metal extraction is presented in this dissertation. Various research areas, covering subjects from photochromic compound syntheses to microchip fabrication techniques are explored to develop microfluidic devices capable of extracting heavy metal ions from drinking water. Through integration of the beneficial characteristics of both...
Microreactors offer high rates of heat transfer able to intensify highly endothermic biomass reforming reactions in supercritical water. In this study, two continuous flow microreactor configurations were used to gasify biomass constituents in supercritical water. The first reactor configuration was a micro diameter stainless steel or Hastelloy tube (508 µm...
When data are not missing at random, approaches to reduce nonresponse bias include subsampling nonresponding units and modeling. The objective of this thesis is to develop unbiased and precise model-assisted estimators of the population total that are applicable to data from a complex survey design with nonignorable nonresponse. When information...
This thesis describes circuit architectures and techniques that facilitate the
automatic synthesis and fabrication of analog-to-digital converters (ADCs). Since
automated synthesis already exists for digital circuits and is part of the digital
circuit design flow, this work demonstrates the feasibility of ADC synthesis with
little or no modification to presently...
We examined how the experiences of World War II and Korean War veterans,
including prewar, warzone, and postwar factors, affected PTSD symptoms in later life.
This dissertation consists of two studies. In Study 1, four different hypotheses from a
lifespan approach were examined (King et al., 1996): stress evaporation (only...
With little previous research on Astragalus peckii (Fabaceae), a state-listed
Threatened species in Oregon, I investigated three facets of its biology which are
integral to the conservation and management of the species. First, a four-year
demographic study of two large populations revealed increasing population growth at
one site (Chiloquin) and...
Renewable energy resources, such as wind, solar, and wave, have a number of advantages compared to traditional fossil fuels. Numerous studies attest to the physical potential for wave energy development in Oregon. In transitioning from conventional fossil fuel to alternative energy provision, citizen understanding of the global energy problems and...
A firm's productivity is composed of two parts: pure technical change and location-specific (agglomeration) externalities. Regional productivity is thus an aggregation of productivity of firms producing similar goods and located in a given region. International trade can affect both components of regional productivity. First, trade openness in a closed economy...
The kinetics of physical and chemical processes controlling the precipitation of iron oxide minerals in unsaturated media were investigated in this study. The characteristic morphology, mineralogy, and chemistry of iron oxides were also explored. Laboratory column experiments using fine and coarse grades of silica sand were conducted to compare the...
Moisture intrusion in residential structures can lead to substantial fungal decay and this damage costs billions in repair/replacement costs. The extent of damage and the rate at which it occurs are primarily dependent on the wood moisture content and temperature in the structure. Determining the risk of decay for various...
Cystic ovarian disease (COD) is an anovulatory condition in cattle
that afflicts between 6-18% of all dairy cows in the US. Ovulation is
dependent on the plasminogen activator (PA) family of proteases
and protease inhibitor for proteolysis, culminating in follicular rupture.
Failure of the follicle to ovulate suggests an aberration...
Pacific sardines (Sardinops sagax) are an economically and ecologically important forage fish which transfer energy from planktonic primary producers and secondary consumers to upper trophic predators. Previous genetics studies of Pacific sardine suggested a panmictic population with a shallow genetic structure. However, more than one subpopulation within the Central California...
Advances in process technologies have led to the development of low-power high speed digital signal processing blocks that occupy small areas. These advances are critical in the development of portable electronic devices with small feature size and long battery life. However, the design of analog and mixed-signal
building blocks, especially...
Fluid-structure interaction (FSI) is an interesting and challenging interdisciplinary area comprised of fields such as engineering- fluids/structures/solids, computational science, and mathematics. FSI has several practical engineering applications such as the design of coastal infrastructure (such as bridges, levees) subjected to harsh environments from natural forces such as tsunamis, storm surges,...
This dissertation presents the results of a research effort conducted to better understand the stress-strain, volume change, shear band formation, and strength characteristics of normally consolidated anisotropic clay under fully three-dimensional stress states. A series of consolidated drained true triaxial tests with a constant mean effective stress and constant Lode...
This dissertation presents the results of statistical analyses of large climate datasets from two time intervals – the 20th century instrumental record and the proxy record of the last deglaciation – in order to understand the forcings and mechanisms of past climate variability.
A longstanding question in climate dynamics concerns...
Delta-sigma analog-to-digital converters (ADCs) are suitable for many applications due to several advantages such as relaxed anti-aliasing filter, high signal-to noise and distortion ratio (SNDR) and most important of all, reduced sensitivity to
analog imperfections.This thesis introduces several structures to overcome loop imperfections and stability issues in delta-sigma modulators. First,...
As the aging population continues to grow the world over, age related complications become more and more apparent among the elderly population. One such complication is age associated memory impairment, which makes the elderly more dependent on caregivers early on. NMDA receptors in the brain are important for memory formation,...
The purpose of this study was to investigate the development of an interactive
aquarium design motivated by the employment of an innovative technology used in
scientific research. The study was informed by research on free-choice learning
describing the effects of interactive devices on visitor learning, engagement, and
attitudes. The researcher...
The genus Phytophthora comprises numerous plant pathogens in both natural and managed ecosystems. For Phytophthora spp. that infect roots, dispersal occurs in soil water through a combination of advection and swimming of specialized motile propagules (zoospores). Specific biological and physico-chemical processes, however, remain poorly understood, due to difficulties in studying...
Relationships between myosin heavy chain (MHC) isoform content and
eccentric-induced damage were investigated in chemically skinned muscle fiber
segments. Fibers were subjected to an eccentric contraction standardized for strain
magnitude (0.25 fiber length) and velocity (0.50 maximal shortening velocity).
Fiber MHC isoform content was identified by SDS-PAGE. Pre- to post-eccentric...
The purpose of this study was to understand, through nontraditional student perspectives, how institutional practices of postsecondary proprietary schools may influence the success of moderately to highly nontraditional students. The study was undertaken for these reasons: (a) A large and growing number of higher education students are nontraditional, putting them...
The thermophilic cyanobacterium Thermosynechococcus elongatus was examined for the ability to sequester CO₂ while producing hydrogen (H₂), polyhydroxybutyrate (PHB), lipids, and glycogen. H₂ was produced at a maximum rate of 188 nmol H₂ mg Chl a⁻¹ hr⁻¹. Hydrogen production occurred in the presence of methyl viologen but the cells were...
The primary goal of this study is to access the processes that alter primary melts after segregation from a mantle source and ultimately form petrologic Layers 2 and 3 of the Ocean Crust. Mineral, melt inclusion, and whole rock chemical compositions are utilized to further the understanding of 1) the...
Studies on the positive effects of stress, called stress-related growth (SRG), are increasing, and there are a variety of contradictory theoretical models and findings in the literature. This dissertation compared several of these models in two studies, using two waves of data from the Davis Longitudinal Study, a study of...
Sagebrush steppe ecosystems are one of the most widespread but endangered ecosystems in North America. A diverse array of human-related stressors has gradually compromised these ecosystems' resilience to disturbance and invasion by Bromus tectorum (cheatgrass). The role of the foundational shrub Artemisia as a driver of herbaceous community structure and...
Ocean wave energy shows great potential as a developing form of renewable energy. However, challenges arise in maturing this technology to achieve cost-effective energy conversion. Development and testing of wave energy converters can be problematic due to the harsh environment in which they are operated. To promote development of this...
Phase-Locked Loops (PLLs) are essential building blocks in many communication systems. Designing high performance analog PLLs in the presence of technology imposed constraints such as leakage, poor analog transistor behavior, process variability, and low supply voltage is a challenging task. To overcome these drawbacks, digital PLLs (DPLLs) have recently emerged...
Although the incidence of non-contact anterior cruciate ligament (ACL) injuries is greater among women than men athletes, the factors that contribute to this greater risk of injury are not well understood. One relevant question is whether decision making during landing influences the biomechanical and neuromuscular factors thought to contribute to...
Fall-planted barley makes the best use of available precipitation in the Pacific Northwest of the United States. This growth habit is also suitable to many other areas of the world. A prerequisite for production in most of these areas is tolerance of low temperature during the vegetative growth stages. Fall-planted...
Habitat for wildlife species that depend on sagebrush ecosystems is of great management concern. Evaluating how management activities and climate change may affect the abundance of moderate and high-quality habitat necessitates the development of models that examine vegetation dynamics, but modeling tools for rangeland systems are limited. I developed state-and-transition...
The flow of incompressible, viscous fluids in R³ is governed by the non-linear Navier-Stokes equations. Two common linearizations of the Navier-Stokes equations, the Stokes equations and the Oseen equations, are studied in this thesis using probabilistic methods.
The incompressibility condition presents new challenges for the well known theory relating partial...
The degenerate nature of the metric on null hypersurfaces creates many difficulties
when attempting to define a covariant derivative on null submanifolds. This dissertation
investigates these challenges and provides a technique for defining a connection on null
hypersurfaces in some cases. Recent approaches using decomposition to define a covariant
derivative...
Increased sales of surimi seafood, with the majority as crabstick in the United States indicates that surimi based products are becoming more popular. With growing popularity, there is increased competition for market share. Under these circumstances, some companies may be willing to sacrifice product quality in order to facilitate manufacture...
We investigate a number of techniques for increasing throughput and quality of media applications over wireless networks. A typical media communication application such as video streaming imposes strict requirements on the delay and throughout of its packets, which unfortunately, cannot be guaranteed by the underlying wireless network due inherently to...
Five U.S. high performance research reactors (HPRRs) are currently part of an international nonproliferation program with the objective of ultimately converting their highly enriched uranium (HEU) fuel to a new high density, low enriched uranium (LEU) fuel while still maintaining their reactor kinetic and thermal hydraulic performance. A uranium-molybdenum (U-Mo)...
Engineers, in practice, are often faced with the challenge of evaluating a fire-damaged structure and developing a rehabilitation and retrofit plan. In order to decide on a rehabilitation and retrofit plan, information on thermal degradation of building materials and connections are vital. A critical knowledge gap exists in terms of...
Interesting rovibrational characteristics of two D_(3h) oblate symmetric top molecules were studied. Hamiltonian models for the fine rovibrational level structure of [1.1.1]propellane (propellane) were obtained for many low-lying modes. Ground state parameters (GSP) that are not exclusively K^(2n) dependent were obtained. Initially, the GSP were used in conjunction with density...
Historical concepts of Clavicipitaceae have included a broad range of species that display diverse morphologies, ecological modes and host associations. When subjected to multigene phylogenetic investigation of evolutionary history, the family was found to be polyphyletic, largely driven by diversity in the genus Cordyceps, previously containing over 400 taxa. The...
Fire is an important disturbance mechanism in big sagebrush (Artemisia
tridentata) communities, yet little is known about wildlife population dynamics during
post-fire habitat succession. I estimated the abundance of small mammals and birds in
relation to fire history in mountain big sagebrush (A.t. spp. vaseyana) communities on the
Sheldon National...
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...
Eukaryotic small RNA (~20-30 nucleotides) are diverse regulatory molecules that repress gene expression at the transcriptional and post-transcriptional levels, defend hosts against invading viruses and defend genomes against selfish DNA elements. Small RNA populations are studied by high-throughput sequencing of the total small RNA fraction isolated from cells, however, the...
Changes in the type and amount of plant inputs can occur gradually, as with succession, or rapidly, as with harvesting or wildfire. With global change it is anticipated that both gradual and immediate scenarios will occur at increasing frequency. Changes in vegetation inputs alter the quality and quantity of soil...
Silicon carbide (SiC) and aluminum nitride (AlN) exhibit a combination of thermal and mechanical properties that are relevant to applications in electronics, aerospace, defense and automotive industries. However, the successful translation of these properties into final applications lies in the net-shaping of these ceramics into fully dense microstructures. Increasing the...