The composition of global agricultural trade is shifting from primary commodities to processed foods in terms of value and quantity. It is important to understand the linkages between agriculture and food processing to identify the sources of the structural change in agricultural trade. The question addressed by this research is...
This paper describes an attempt to ascertain the enzyme system
responsible for melanin formation in a melanin-and-microsclerotia-forming strain of Verticillium albo-atrum Reinke and Berth.
Previous work showed that near-UV radiation (3200-400 A⁰) inhibits
melanin synthesis and microsclerotia development in this strain and
that catechol almost wholly reverses this inhibition. During...
Projects in forestry and civil engineering depend on accurate information, which is often acquired through remote sensing techniques. One of the remote sensing technologies that has gained importance in the last decade is light detection and ranging (lidar), which describes the surveyed area with 3D points, presented as point clouds....
Instruments which combine the features of a digital-to-analog
conversion and a linear-to-logarithmic scale change usually perform
the digital-to-analog conversion first. These instruments are accurate
to within five or ten percent over ranges of five or six decades.
This thesis presents a method which uses combinatorial logic
to perform the linear-to-logarithmic...
The quest for greater computer-system speed has brought
about a continuing increase in the parallelism of these systems. In
particular, the number of processors and other devices which are
required to access the same core-memory not for economy, but
for the advantages to be derived from using the memory as...
PURPOSE: We tested the hypothesis that the unsupervised, isokinetic 3- minute all-out cycling test (3MT) would be a valid and reliable way to determine end power (EP) and work done above end power (WEP). Additionally, we hypothesized that EP would successfully demarcate between heavy and severe-intensity exercise and thus represent...
The purpose of this study is to determine if the
ntoraines damming proglacial Carver Lake are ice-cored.
The methodology to be employed consists of interpretation
of aerial photographs and field observations. The results
of these studies will be compared. to past research of
known ice-cored moraines in other regions of...
Approximately one quarter of America's students
leave school prior to graduation. Teaching practices
need to be examined if schools are to effectively deal
with the student population. at highest risk of dropping
out. The purpose of this study was to investigate the
attending behaviors high school teachers directed to
students...
Subduction zone earthquake and tsunami hazards affect tens of millions worldwide and the recurrence of these disasters can be evaluated with paleoseismic techniques, because earthquake cycles (and their supercycles) typically span many millennia. In these three chapters, I discuss a suite of analyses I use to evaluate the sedimentary record...
Full Text:
DISSERTATION OF
Jason R. Pa on for the degree of Doctor of Philosophy in Oceanography presented on
January 9
Ecological resources available to freshwater fish shift spatially, temporally and across life stages. To better understand how spatial-temporal availability of resources influence fish, I examined the phenologies of hatching and emergence of Coho Salmon (Oncorhynchus kisutch) in streams with contrasting and strongly defined seasonal thermal variability. The study streams included...
Alternative male phenotypes in salmonine fishes arise from individuals that mature as either larger and older anadromous marine-migrants or as smaller and younger freshwater residents. Variability in age and size of males at maturity is hypothesized to be preceded by early differences in growth in size and lipid storage. Water...
Large wood has been utilized in many restoration projects to improve in-stream habitat in the Pacific Northwest for salmon. However, the benefits of this practice remain the subject of ongoing debate and evaluation of these projects has scarcely been done for non-salmonid species such as lamprey. In this study we...
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Jason B. Dunham
Large wood has been utilized in many restoration projects to improve in
Internal curing is a term used to describe a process in which curing water is provided to a concrete mixture from inside the mixture. Internal curing water has typically been provided in North America mixtures by using prewetted porous materials, like fine lightweight aggregate (FLWA). Alternative materials, such as superabsorbent...
Tightness-looseness (TL) is a cultural construct that measures the level of social norms present in a community, and the level of scrutiny of deviance from these norms. This construct offers a unique foundation for investigating how norms influence behavioral processes. Research in TL is relatively young, creating a frontier of...
The use of fly ash as a supplementary cementitious material (SCM) has increased in the last century due to its various environmental benefits as a recycled product. Within the last 60 years, it has been found that it can be used to effectively control damage induced by Alkali-Silica Reaction. However,...
In the field of civil infrastructure, bridge desks are typically constructed using high performance concrete (HPC). Concrete bridge decks demand qualities such as low permeability, high abrasion resistance, superior durability, and long design life. Over decades of field and laboratory experience, many HPC bridge decks have been found to be...
Studies of the effects of forest harvest on streams and fish have a long history in the Pacific Northwest. Results of this work have prompted development of new forest harvest practices that are more protective of these resources, but the effectiveness of these new practices has not been fully evaluated....
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Jason B. Dunham
Studies of the effects of forest harvest on streams and fish have a long
Previous research has shown that using fine lightweight aggregate (FLWA) can be a promising strategy to mitigate alkali-silica reaction (ASR) in mortar and concrete. While several possible theories were proposed by researchers, discrepancies in testing methods, materials, and supporting evidence still exist. Therefore, this study was initiated. There are two...
The Critical Power - W’ model has many advantages compared to the traditional VO2max test, including tracking fitness changes over time in well trained athletes, predicting performances due to its discrete aerobic and high intensity tolerance variables, and prescribing exercise intensities with increased accuracy. However, a major disadvantage of this...
Coastal cutthroat trout (Oncorhynchus clarkii clarkii) and cottids (Cottus spp) commonly co-occur in headwater streams in western Oregon. Little is known about the comparative trophic ecology of these species or how they respond to seasonal scarcity of resources. In this study I evaluated the seasonal variability in diets and consumption...
Objectively quantifying workload is challenging due to a variety of factors. One way to measure workload is by training impulse (TRIMP). TRIMP uses time in physiologically significant heart rate zones to quantify a workload for a given bout of physical activity. Tracking average workload over time can then be used...
High Performance Concrete (HPC) is used in our crucial pieces of infrastructure, such as bridge decks, due to its enhanced durability and engineering properties. However, HPC is highly susceptible to early-age cracking. Cracking within the first months of a bridge deck’s lifespan can severely hinder its long-term performance and durability....
Sonification, or the “technique of rendering sound in response to data and interactions” [1], is an alternative to visual graphs and has the potential to make data more interpretable and accessible. As a combination of the arts (music) and the sciences (data), sonification is an interdisciplinary tool for connecting people...
Alkali-silica reaction (ASR) is one of the leading causes of concrete deterioration throughout the world, and affects both structural and non-structural elements. Despite strong research efforts since its discovery by Stanton in the late 1930s, this deteriorating reaction is still not clearly understood nor are proper preventative measures effectively applied...
The purpose of this thesis is to examine and compare sustainable design methods used in the United States and Chile, focusing on sustainable materials and certification programs, to see if sustainable design methods used in the United States can be implemented in Chile to further its sustainable development. Through literature...
High early strength (HES) concrete is becoming increasingly used to repair damaged concrete pavement sections. The use of HES concrete enables the repaired pavement to be opened to traffic within hours of placing the concrete. A common approach used for the rapid repair of concrete pavement consists of closing a...
This dissertation demonstrated that the electrical properties of complex oxide-based perovskite materials could be controlled through the careful modification of both material composition and structure. This was first shown through the modification of lead zirconate titanate (Pb(Zr0.52Ti0.48)O3, PZT) solid solutions with bismuth indate (BiInO3, BI) where the relative stability of...
The purpose of this study was to examine the validity and reliability of the 30-minute cycling time trial to estimate the heart rate at lactate threshold. Recreationally trained cyclists and triathletes (n = 47) performed 3 tests in random order: 1) One graded exercise test to directly determine lactate threshold...
Mean-squared errors of surface geostrophic velocity estimates from the crossover and parallel-track methods are calculated for altimeters in the Ocean Topography Experiment (TOPEX)/Poseidon and Jason orbits. As part of the crossover method analysis, the filtering properties and errors of cross-track speed estimates are examined. Velocity estimates from both the crossover...
We assessed use and selection of cover by coastal cutthroat trout (Oncorhynchus clarkii
clarkii) in six headwater streams in three watersheds in western Oregon, USA during the summer low flow period from 1 August and September 30, 2007. We tagged 1037 coastal cutthroat trout (>100 mm) with passive integrated transponder...
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Jason B. Dunham
We assessed use and selection of cover by coastal cutthroat trout
In this study, we used a combination of conventional statistical analyses and mechanistic bioenergetics models to understand the potential effects of environmental variability on growth of stream-living fishes in four headwater streams subject to upstream forest harvest. We focused on two common fish consumers in headwater streams in the Pacific...
Shallow lakes exist in either a clear or turbid state, with the clear state characterized by an abundance of aquatic macrophytes, diverse aquatic biota, low water column nutrients and phytoplankton biomass, whereas the turbid state is characterized by the opposite. These two distinct states are maintained by reinforcing (positive) feedback...
Automated decision aids can improve human decision-making but the benefits are often compromised by inefficient use. The current experiment examined whether metacognition—the ability to assess self-performance—and numeracy—the ability to understand and work with numbers—predict the efficiency of automation use in a signal detection task. Two-hundred twenty-one participants classified random dot...
When observers monitor for infrequent signals for extended durations, they generally experience a decline in detections over time. This decline is termed the vigilance decrement. Current theories of vigilance attribute the decrement to three potential mechanisms: conservative shifts in response bias, losses of sensitivity, and an increased rate of attentional...
Microbial ecology has been transformed by metagenomics, the study of the genetic in-formation in entire communities of organisms. In the following we develop metagenomic tools arising from the classic Wasserstein metric as applied to questions regarding the diversity between microbial communities. We provide a novel proof of the characteriza-tion of...
The LA Book is a free-to-students Linear Algebra textbook written at the introductory
level and suitable for teaching MTH341 at Oregon State University. It functions both as
a traditional, printed book (rendered via LaTeX) and as an online textbook (rendered via
HTML), viewable via any modern web-browser. It is built...
Age-related decline in the capacity of endogenous antioxidant systems
complicates pharmaceutical use by the elderly by potentially increasing the toxicity of
some compounds. Of particular interest is chemical detoxification via glutathione (GSH)
and attendant GSH-requiring detoxification enzymes, e.g. GSH peroxidases (GPX) and
GSH S-transferase (GST). These enzymes have been shown...
Anthropogenic CO₂ emissions are shifting the global climate equilibrium, causing widespread losses in biodiversity. Anthozoan cnidarians are some of the species most vulnerable to environmental change. Environmental stress causes corals and sea anemones to expel their endosymbiotic algae, which constitute a primary source of nutrition for some Anthozoa. Carbonic anhydrase...
Debris flows, common disturbances in many mountainous areas, initially scour or bury stream habitats; however, debris flows deliver vast amounts of wood, boulders, and gravel that may ultimately form complex stream habitat to potentially support a diverse salmonid assemblage. The materials deposited by debris flows would otherwise be inaccessible to...
Northern Spotted Owls (Strix occidentalis caurina) inhabit productive forests that historically supported frequent, large, variable-severity fires in the Klamath province of southwestern Oregon occur in complex. The potential for high-severity wildfire remains high throughout this region, so remaining spotted owl habitat is at risk. An adaptive management approach to fire...
Maximal aerobic capacity (V̇O₂max) is the most widely used measure for assessing cardiorespiratory fitness. It is a strong contributor to performance in endurance sports, predicts functional capacity in older adults, and is related to overall disease risk. As such, it is important that testing methodologies for determining V̇O₂max provide valid...
Several reports related to dams and dam removal have been released this decade by non-governmental organizations including Dam Removal: Science and Decision Making by The Heinz Center which focused on small dams, since most of the dams removed to date as well as those likely to be removed in the...
2020 and 2021 brought the first reported outbreaks of salmonellosis epidemiologically linked to dry bulb onions in the United States. Outbreak investigations were not able to implicate a specific source of the contamination but speculated that contaminated water was a significant contributor. The Produce Safety Rule established minimum standards for...
I evaluated hypotheses related to growth as a driver of depth use and diel vertical migration by bull trout (Salvelinus confluentus) in a thermally stratified reservoir. I applied a bioenergetic model to evaluate growth of bull trout in relation to potential patterns of diel depth use by bull trout in...
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Jason B. Dunham
I evaluated hypotheses related to growth as a driver of depth use and diel
Chloride-induced corrosion is one of the primary causes of the degradation of reinforced steel in concrete structures. Currently, the rapid chloride permeability test (RCPT) is the most specified method to determine the concrete’s resistivity to chloride ingress, thus a determining factor in assessing the durability of concrete. While it is...
High early strength concrete (HESC) allows for faster construction with less impact on traffic, thus reducing the indirect costs associated with a project. There are multiple methods for achieving early strength, such as alternative cements like calcium sulfoaluminate (CSA) or chemically accelerated portland cements. The standard criteria for an HESC...
During applied signal-detection (e.g., airport-baggage screening) human operators can be assisted in their decision-making process by automated devices. Automation implementation is aimed at increasing performance relative to unaided levels. Generally, this intended effect is empirically observed. However, operators consistently fall short of optimal levels of aided performance, indicating suboptimal aid-use...