Mycobacterium avium is an intracellular pathogen that is associated with disseminated
infection, especially in patients with acquired immunodeficiency syndrome (AIDS). It
appears that patients with AIDS acquire M. avium mostly through the intestinal tract,
and that bacteria enter the intestinal wall at the terminal ileum. Previous studies have
found that...
Recent studies of headwater streams have demonstrated their importance to overall watershed biodiversity, nutrient cycling, and energy flux. However, little attention has been paid to long-term effects of forest harvest on macroinvertebrate communities in headwater streams. This study investigated headwater stream macroinvertebrate communities in the H.J. Andrews Experimental Forest, Oregon,...
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 thesis presents a comparison of time-domain and frequency-domain algorithms for phase noise calculation in oscillators. Floquet theory provides the mathematical foundation for these calculations and the numerical methods employ perturbation projection vectors (PPVs). The PPVs are an estimate of an oscillator's sensitivity to noise.
The in-house circuit simulator SPICE3...
North American sagebrush (Artemisia spp.) ecosystems are suffering from
reductions in habitat extent and quality. Only about 50% of sagebrush remains
from pre-settlement conditions, and much of the remaining habitat is
fragmented or degraded by invasive species, fire suppression and overgrazing.
Sagebrush-obligate species are experiencing population declines as a result...
Habitat loss causes a reduction in available resources for wildlife, alters the configuration of remaining habitat, and may isolate wildlife populations. White-breasted nuthatches (Sitta carolinensis) are experiencing long-term population declines in the Willamette Valley of Oregon, where they are historically associated with oak woodlands. As secondary cavity-nesters, white-breasted nuthatches may...
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...
For the first objective of this thesis, we attempt to understand the role of water flow and directionality in determining steelhead (Oncorhynchus mykiss) and spring/summer and fall Chinook (O. tschawytscha) migration patterns within the Columbia River Estuary and plume by integrating recent advances in biotelemetry and environmental observation and forecasting...
Functional programming is concerned with referential transparency, that is, given a certain function and its parameter, that the result will always be the same. However, it seems that this is violated in applications involving uncertainty, such as rolling a dice. This thesis defines the background of probabilistic programming and domain-specific...
This thesis presents new, compact configurations for RF/microwave bandstop and lowpass filters for embedded passive applications. A simple design methodology is presented for designing the folded-transmission line filters on a microstrip platform. Unlike the conventional stub-loaded filter designs, the proposed folded-line filters will have practical dimensions for a wide range...
Experiments were conducted to determine the influence of cultural management practices on weed growth in nursery containers. Experiments 1 and 2 evaluated the effects of dolomitic lime rate and application method on substrate pH, creeping woodsorrel (Oxalis corniculata L.) establishment in containers, and growth of azalea (Rhododendron ‘Rosebud’) and pieris...
In 2000, the US Congress responded to the industry-wide constriction of the West Coast groundfish industry by allocating $5 million in disaster relief for Oregon, Washington, and California. Each state, with minimal federal oversight, designed and executed its own disaster response program to help impacted members of the fishing industry...
Canopy gap formation is a major factor contributing to maintenance of overstory species diversity and stand structure in forests and may be integral to development of understory shrub and herb layers as well. Acknowledgement of gap formation as a fundamental feature of natural forests has led to consideration of gaps...
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...
The purpose of this thesis is to explore dependency speculation in Dynamic Simultaneous Multi-Threading (DSMT). DSMT is a microprocessor architecture which attempts to extract Thread Level Parallelism (TLP) from single-threaded programs at run-time. This is accomplished by running multiple iterations of program loops in parallel. The DSMT architecture was originally...
Previous research in South Fork Hinkle Creek suggested that coastal cutthroat trout exhibit an aggregated spatial pattern across multiple spatial scales. To evaluate the persistence of the observed abundance patterns and identify factors that affect those patterns, half-duplex passive integrated transponders (PIT-tags) were implanted in 320 coastal cutthroat trout (>...
Radiotelemetry was used to study the seasonal movements and habitat use of adult westslope cutthroat trout Oncorhynchus clarki lewisi in Roberts
Creek and Rail Creek, headwater tributaries of the John Day River, Oregon,
from September 2000 to December 2001. The objectives were to (1)
describe adult cutthroat trout life history...
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...
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....
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 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...
Biological agents and their products commonly cause foodborne illnesses. In the United States it is estimated that there are over 76 million cases of foodborne illnesses each year, resulting in an economic loss of approximately $40 billion. These high figures demonstrate the need for bioassays that display a rapid and...
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...
Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), a shade intolerant species, and western hemlock (Tsuga heterophylla (Raf.) Sarg.), a shade tolerant species, were compared to learn more about the temporal pattern of release from suppression in both species, whether hydraulic architecture or photosynthetic capacity constrain release and how wood functional properties change...
The objective of this study was to examine vegetation and vegetation change in Eritrea over a period from the mid 1980s to 2002 using satellite remote sensing, and relate observed changes to the recent history of drought and war in the region. Specific objectives were (1) to examine vegetation change...
Continuously tunable diode laser sources coupled to single-mode fiber are useful sources for fiber Bragg grating (FBG) strain sensors. This paper describes the
development and fabrication of such a device. An introduction is given describing
applications of tunable lasers and some of the different methods of creating a tunable
diode...
This research was designed to broaden the understanding of how timber-harvest affects aquatic macroinvertebrates in perennial and intermittent headwater streams. This study compared emergent and benthic macroinvertebrate assemblages from 20 headwater streams in the central Oregon Coast Range that varied by harvest condition and flow duration. Through comparison of the...
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...
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...
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...
Fire is a major disturbance process in many forests. Long-term studies of the biogeochemical effects of fires, especially on soils, are very rare.
Consequently, long-term effects of fire on soils are often hypothesized from
short-term effects. In a chronosequence study, I studied 24 western Cascades
(Oregon) forest stands thought to...
There is a large and growing market for portable consumer audio products
with very small size. As the size of these products is reduced, the area occupied
by batteries becomes significant and hence limits the number of batteries to one.
In order to build such small products, high levels of...
Previous observations of light levels and phytoplankton abundances along the Oregon coast demonstrated that phytoplankton attenuated light sufficiently to potentially limit the growth of intertidal macrophytes and therefore structure local intertidal communities. Inspired by this observation, in spring 2004, I initiated a study to quantify the direct and indirect benthic...
Previous research has revealed gender differences that impact females’ willingness to adopt software features in end users’ programming environments. Since these features have separately been shown to help end users problem solve, it is important to female end users’ productivity that we find ways to make these features more acceptable...
Recently, continuous-time ΔΣ modulators are appearing increasingly often in both the literature and the marketplace due to their features of inherent antialiasing and relaxed requirements for opamp and so on. However, several nonideal factors such as clock jitter, excess loop delay, inter-symbol interference and so on, degrade the SNR performance...
A large number of sequential decision-making problems in uncertain environments
can be modeled as Markov Decision Processes (MDPs). In such settings, an agent
can observe at each time step the state of the environment and then executes an
action, causing a stochastic transition to a new state of the environment...
Paclitaxel is a very important anticancer drug commonly called Taxol®.
We know from previous work (Hoffman, et al., 1998) that Taxol exists in filbert, Corylus avellana L. material. Quantification of Taxol in filbert plant material is painstaking and hitherto was accomplished by rapidly processing single batches in a complicated procedure...
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 links together two very complicated, but very important subjects: media bias and metaphor. More specifically, this study investigates whether or not examining a media outlet's use of metaphor is an effective methodology for investigating media bias. Using cluster analysis, I identified the source metaphors most commonly used on...
The design of a 10-bit pipelined charge redistribution DAC employing MOSCAPs biased in their accumulation mode is presented in this thesis. A switched capacitor filter and output buffer have also been designed for the system. The effect of MOSCAP nonlinearity on the performance of the pipelined charge redistribution DAC has...
With the ever-increasing demand for portable devices used in applications
such as wireless communication, mobile computing, consumer electronics, etc.,
the scaling of the CMOS process to deep submicron dimensions becomes more
important to achieve low-cost, low-power and high-performance digital systems.
However, this downscaling also requires similar shrinking of the supply...
End-user programmers, because they are human, make mistakes. However, past research has not considered how visual end-user debugging devices could be designed to ameliorate the effects of mistakes. This paper empirically examines oracle mistakes mistakes users make about which values are right and which are wrong to reveal differences in...
Ultra-wideband (UWB) radio is the transmission of data using an extremely wide bandwidth and very low power spectral density. In this thesis, the mereits and challenges of UWB architectures versus conventional narrowband architectures will be compared. Pulsed UWB systems can be implemented with very simple architectures. These advantages make UWB...
Ferrites have been used for various high frequency applications as bulk
materials. These applications, however, are limited to large dimension devices. In
this thesis, thin film ferrites were deposited from a low temperature solution-based
deposition process that is suitable for micro-scale high frequency applications. The
low temperature nature of this...
A discrete trap model is developed and employed for elucidation of thin-film transistor (TFT) device physics trends. An attractive feature of this model is that only two model parameters are required, the trap energy depth, E[subscript T], and the trap density, N[subscript T]. The most relevant trends occur when E[subscript...
Dissociation between catabolism and anabolism, generically termed “metabolic uncoupling”, has been studied for aerobic cultures of Shewanella oneidensis MR-1. Under conditions promoting metabolic uncoupling, the cell yield diminishes while the substrate utilization rate remains largely unchanged. The effects of excess substrate conditions and TCS addition on the metabolism of pyruvate...
Digital phase-locked loops (PLLs) have been receiving increasing attention recently due to their ease of integration, scalability and performance comparable to their analog counterparts. In digital PLLs, increased resolution in time-to-digital conversion is desirable for improved noise performance. This work describes the design and simulation of a stochastic time-to-digital converter...
Circuits operating outside the earth’s atmosphere are more vulnerable to cosmic radiation and require special design consideration. The purpose of this work is to explore methods of mitigating the effect of radiation in phase locked loop (PLL) circuits. Several voltage controlled oscillators (VCOs) and two complete PLLs are designed and...