Island systems and species are susceptible to extinction because of their small population size and an ecological naiveté from an evolutionary past lacking strong competition and predation. For example, only one-fifth of the world’s bird species occur on islands, yet more than 90% of the avian extinctions witnessed during historic...
This dissertation consists of two papers on International Trade topics. The first paper addresses the development of trade patterns between countries in transition and developed economies. The second paper focuses on the nonparametric estimation of the Knowledge-Capital model of multinationals. The first paper provides a framework for understanding patterns of...
Indole-3-carbinol (I3C) and 3,3'-diindolylmethane (DIM), a primary I3C
derivative in vivo, are known chemopreventive agents available as dietary supplements.
I3C was found to suppress or enhance tumors in several animal models.
Chemoprotection is attributed to the ability of indoles to alter carcinogen metabolism
effectively blocking initiation. However, mechanisms for enhancement...
Advanced Very-High Resolution Radiometer 4-km data were collected over the northeast Atlantic for May-August, 1995-1999. Aerosol optical depth was retrieved in cloud-free pixels. In pixels containing clouds from only single-layered, low-level systems, a retrieval scheme that accounts for partly-cloudy pixels was used to retrieve: cloud optical depth, droplet effective radius,...
The purpose of this study was to explore the experiences, events, and circumstances that provided Latino educators the opportunity for ascendancy to the presidency of a California community college. This study aimed to recapture the individual experiences of current Latino community college presidents from working class, immigrant family backgrounds as...
Designing spectral efficient, high-speed wireless links that offer high quality-
of-service and range capability has been a critical research and engineering challenge. In this thesis, we mainly address the complexity and performance issues of
channel estimation and data detection in multiple-input multiple-output (MIMO)
orthogonal frequency division multiplexing (OFDM) systems over...
The viscosity of Zr[subscript 41.2]Ti[subscript 13.8]Cu[subscript 12.5]Ni[subscript 10.0]Be[subscript 22.5] (Vit1) has been measured above the liquidus temperature, T[subscript liq]=1026 K, using a high vacuum high temperature rapid annealing furnace equipped with a Couette Concentric Cylinder Rheometer. Steady state measurements have been taken over a temperature range of 1075-1300 K and...
During the past 30 years, numerous studies have focused on the toxicities of polycyclic aromatic hydrocarbons (PAH). Laboratory and field studies have helped elucidate the detrimental effects of these chemicals on growth, reproduction and immune response. Polycyclic aromatic hydrocarbons are in the priority list of chemicals to be studied by...
This research employed both quantitative and qualitative research methodologies to
explore the impact of mobile wireless technology (MWT) in higher education classrooms.
The methodology was developed using systems engineering concepts. A methodology to
evaluate and compare the cost, cost-effectiveness and cost-utility of different MWT
configurations was also developed. Five outcomes...
Two-phase flow in a fractal-like branching microchannel heat sink may have
enhanced heat transfer capabilities over single phase flow in the same branching
channel network. In order to exploit this potential, a complete understanding
of flow boiling in this geometry is required. The fractal-like geometry is similar
to that of...
The role of the nonionic surfactant Tween 80 on the behavior of the therapeutic recombinant protein Factor VIII (rFVIII) was investigated at solid/liquid and air/water interfaces. In order to provide a model system to compare results obtained for the complicated rFVIII-Tween system, a well-characterized globular protein lysozyme was used. The...
Four aspects of factors influencing the accuracy of nondestructive chlorophyll (Chl) and nitrogen (N) measurement in fresh leaves were studied: (1) optimum wavelength (OW) identification; (2) indices development and evaluation; (3) influence of leaf properties; and (4) influence of meter parameters and sampling technique. Results were used to develop indices...
This study was divided into three stages. The first phase of the study aimed to examine factors influencing the students' participation in physical activity. Eight female and male university students participated in the focus group. It was found that the participants' perceived benefits of physical activity were physical, psychological and...
Water availability is a critical limiting element in semi-arid ecosystem productivity and presents particular challenges in Sahelian countries such as Senegal. The landscapes are characterized by the presence of two common semi-arid shrubs (Piliostigma reticulatum and Guiera senegalensis), both of which may be important hydraulic regulators in these water-limited ecosystems....
Cordyceps is a genus of perithecial ascomycetes. It includes over 400 species
that are pathogens of arthropods and parasites of the truffle genus Elaphomyces. Based
on the morphology of cylindrical asci, thickened ascus apices and filiform ascospores,
it is classified in the Clavicipitaceae (Hypocreales), which also includes endophytes
and epiphytes...
The purpose of this study is to investigate the performance and stability of
the gas-injection enhanced natural circulation in heavy-liquid-metal-cooled systems.
The target system is STAR-LM, which is a 400-MWt-class advanced lead-cooled
fast reactor under development by Argonne National Laboratory and Oregon State
University. The primary loop of STAR-LM relies...
I examined the avian biogeography of the islands of Lago Gatun, Panama, in an effort to better understand the effects of forest fragmentation in this biodiverse region, and specifically to understand the importance of fragment isolation and the mechanism behind its effects on tropical bird distribution. I combined exhaustive surveys...
Lymphomas and leukemias are the most common cancer in children and young adults and in utero exposure to carcinogens may contribute to the etiology of these cancers. A polycyclic aromatic hydrocarbon (PAH), dibenzo[a,l]pyrene (DBP), was administered to pregnant mice (15 mg/Kg b.w., gavage) on gestation day 17. Significant mortalities in...
Studies towards the total synthesis of (-)-gymnodimine (1), a marine neurotoxin with a unique molecular architecture and pronounced biological activity, are described. These studies resulted in a convergent approach to the advanced intermediate 315, containing the C3-C32 section of 1. Two synthetic routes were developed to construct the tetrahydrofuran subunit...
The current project investigated the influence of three life transitions on the intimacy and contact siblings share in early adulthood. Using a web-based survey, 260 young adults from two large state universities and community members from the Portland, Oregon area were surveyed about their relationships with a single biological sibling....
The purpose of this study was to examine one case of embezzlement at one community college in order to assess the sociological effects of the embezzlement on that college. The research design for this study was qualitative using a case study approach. Although there was no attempt to generalize the...
Jets in crossflow are used in a wide range of engineering applications and have been studied for more than 60 years. The transversal penetration and structure of a jet placed in a crossflow is known to be strongly three-dimensional. It is believed that, by using a pulsed jet inclined in...
Regression calibration inference seeks to estimate regression models with measurement error in explanatory variables by replacing the mismeasured variable by its conditional expectation, given a surrogate variable, in an estimation procedure that would have been used if the true variable were available. This study examines the effect of the uncertainty...
This dissertation focuses on the life of Dixy Lee Ray as it examines important developments in marine biology and biological oceanography during the mid twentieth century. In addition, Ray's key involvement in the public understanding of science movement of the 1950s and 1960s provides a larger social and cultural context...
This thesis is an investigation of the natural products deriving from marine algae and cyanobacteria and has resulted in the discovery of eleven new secondary metabolites. The structure elucidations of these new molecules were performed using a variety of spectroscopic techniques. Four new macrolides were isolated and characterized from the...
The purpose of this study was to explore the phenomenon of community colleges creating pathways to degree completion in professional-technical programs by breaking degree programs into smaller portions, referred to as "chunks." The purpose or possible advantage of chunking was that it would improve the rate of degree completion among...
Our objectives were to determine 1) the concentration of prostaglandin
F2α (PGF2α) in whole and extended bovine semen, 2) if concentrations of
prostaglandins in extended bovine semen are correlated to fertility, and 3) if PGF2α
administered at the time of artificial insemination would improve conception rate.
Concentration of PGF2α tended...
Many Hymenoptera, with their painful stings and noxious chemical defenses, exhibit bright aposematic warning color patterns and are the most frequently mimicked group of organisms. Such aposematic color patterns are found in parasitic wasps of the Neotropical Compsobracon group (Braconidae). Many members of this group exhibit color patterns similar to...
The Central Oregon High Cascade Range is an anomalously mafic segment of the Cascade Arc due to ongoing intra-arc extension, which allows most magmas to traverse the crust without stalling and evolving to more evolved compositions. North Sister, a composite volcano in this arc segment, has produced a seemingly monotonous...
Community colleges are experiencing a decline in state allocated funding. Traditionally, college administrators look for ways to cut expenditures and raise tuition and fees to make up for the shortfall. Using available land resources to generate a revenue stream may provide revenue for community colleges.
The purpose of this study...
Numerical model and assimilation experiments were conducted in the tropical Pacific Ocean to obtain a better understanding of the processes that control the cold tongue surface mixed layer temperature balance during August 1999 to July 2004. The numerical model was first applied to test two hypotheses (asymmetric background currents and...
The objectives of the experiment were to: 1) determine the relationship
between overstory canopy cover and ungulate herbivory on understory production
composition and diversity and 2) determine the effects of timber harvest, ungulate
herbivory and season of use on botanical composition and nutritional quality of
beef cattle diets. Three randomly...
The purpose of this study was to investigate the knowledge base and instructional
practices of two highly qualified experienced secondary mathematics teachers within
the context of their classrooms during a unit in a geometry class. Data collected from
interviews, classroom observations, pre and post-observation questionnaires, and
detailed analyses of several...
Monophyly of the gomphoid-phalloid clade was confirmed based on multigene phylogenetic analyses. Four major subclades (Hysterangiales, Geastrales, Gomphales and Phallales) were also demonstrated to be monophyletic. The interrelationships among the subclades were, however, not resolved, and alternative topologies could not be rejected statistically. Nonetheless, most analyses showed that the Hysterangiales...
Within systems characterized by substantial spatial and temporal variability, abundances of organisms tend to be higher in localized areas. Within the northern California Current system, the identification of such marine, biological hotspots would be of great importance to resource managers, conservationists, and research planners, and is consequently a growing area...
Commonly proposed ocean wave energy converters (OWEC) use inefficient and maintenance demanding intermediate hydraulic and pneumatic systems. We propose a novel rotary direct-drive OWEC that eliminates these intermediate stages. The new device employs a contactless force transmission system (CFTS) comprising a “piston” and a “cylinder” and a ball screw to...
The use of high throughput molecular methods that allow for the study of bacterial communities in environmental samples is commonplace in microbial ecology. Until recently, fungal community ecology has
focused on isolation, collection of sporocarps, or collection of ectomycorrhizal roots. The techniques used to extract and amplify DNA from environmental...
Jointed goatgrass (Aegilops cylindrica Host) infestations in winter wheat (Triticum aestivum L.) production regions of the central and western USA result in severe economic losses in the wheat market. Field and greenhouse studies were conducted to determine the vernalization requirements of winter wheat, spring wheat, jointed goatgrass, and wheat by...
Digital-to-analog converters (DACs) suffer from static and dynamic nonlinearity problems, which degrade their accuracy and performance. Mismatch errors in the analog components restrict the maximum achievable linearity.
This thesis presents various techniques for correcting these errors. It describes a correction process for the nonlinear behavior of DACs, on three different...
Tan spot of wheat is an economically significant disease caused by the fungal pathogen, Pyrenophora tritici-repentis. Certain races of the fungus secrete Ptr ToxA (ToxA), a 13.2 kDa proteinaceous host-selective toxin that is responsible and sufficient to cause disease in susceptible wheat varieties. Disease symptoms develop only when the ToxA...
As researchers, policymakers and employers begin focusing
on consumer driven health plan models and medical savings
accounts (MSAs), a better understanding of the political
viability of such reform initiatives is necessary. The
purpose of this study was to survey state legislators'
knowledge and perceptions of medical savings accounts
(MSAs) and...
Laboratory data of free surface elevations and fluid velocities were
obtained using a laser-Doppler velocimeter for the case of a periodic wave
plunging over an impermeable, steep (1:10) slope with a fixed bottom roughness.
The measurements were conducted over 15 cross-shore locations from the outer
surf zone to the swash...
This study illustrates geoarchaeological and paleoenvironmental approaches to the
investigation of an active margin coastal setting and provides examples of how information gleaned through examination of the stratigraphic record can reveal depositional signatures that provide insights into the geomorphic and tectonic forces active within coastal river basins. Three case studies...
This dissertation addresses the "multi-machine carryover sequence
dependent group-scheduling problem with anticipatory setups," which arises in
the printed circuit board (PCB) manufacturing. Typically, in PCB manufacturing
different board types requiring similar components are grouped together to
reduce setup times and increase throughput. The challenge is to determine the
sequence of...
Phospholipase C-Jβ (PLCβ) is an important effector enzyme in G-protein-coupled
signaling pathways. Activation of PLCβ by Gα and Gβy subunits has been fairly well
characterized, but little is known about other protein interactions that may also
regulate PLCβ function. A yeast two-hybrid screen of a mouse brain cDNA library
with...
Wildfire impacts have increased in recent years. The management response outlined by recent policy initiatives (e.g., the National Fire Plan, Healthy Forests Restoration Act) emphasizes the use of prescribed fire and mechanized thinning to reduce the risk of future fire events. These policies also call for an unprecedented level of...
This study consisted of two research projects in the Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh) alliance, the most extensive of the big sagebrush complex in the Intermountain West. In the first project, we intensively sampled 107 relatively undisturbed, late seral Wyoming big sagebrush...
This is a phenomenological research study of the lived experience of women student mentors at one community college located in an urban setting on the West Coast. The study participants were women students who served as mentors to other women at the community college who are participants in a returning...
The challenges faced by manufacturing companies have forced them to become more efficient. Cellular manufacturing is a concept that has been accepted as a technique for increasing manufacturing productivity in batch type production by efficient grouping of parts (jobs) with some similarities in processing operations into groups and sequentially matching...