The endemic cyprinids of Lake Lanao, Philippines have been described as a species flock and are thought to be an example of explosive evolution. However, based on historical surveys, 16 of the 18 cyprinid species endemic to Lake Lanao are now believed to be extinct. Furthermore, non-native species have been...
Sea turtles are endangered species that can be censused with aerial surveys, but the number of turtles in an area must be extrapolated to include animals that are submerged. Twenty-one satellite tags were attached to juvenile loggerhead sea turtles (Caretta caretta) in North Carolina. I analyzed surfacing and dive behavior...
Marine ecosystems can be exposed to natural and anthropogenic disturbances that can lead to ecological failures. Marine reserves have been lately suggested to protect marine populations and communities that have been affected by habitat destruction and harvest. This research evaluates the potential role of two marine reserves established in Oregon...
Under laboratory conditions, elevated temperatures accelerated production of gametes. However, when conditioning for spawning at elevated temperatures was
initiated early in the season (January-March), larval survival and number of spat collected were significantly lower than when conditioning was initiated in may or June. At elevated temperatures, broodstock oysters were fed...
Protein microcapsules (PM) were developed as a tool for investigating aspects of dietary protein utilization by mussels, Mytilus edulis trossulus. Digestion of PM in vitro by protease, trypsin, amylase and extracts from the gut of mussels varied significantly depending on the type of protein encapsulated or whether carbohydrates were added...
Air temperatures and soil temperatures at the surface, two inches,
and four inches under a grass cover were recorded over a 93 day period.
These data were used along with other temperature data from bare soil
in the construction of three sets of models for the prediction of
maximum and...
A population of Columbian white-tailed deer (CWTD) was studied on a
refuge (790 ha) in southwestern Washington during 1972-77. Quality of
habitat was considered good for these deer and total population size remained
between 164-230 as determined by mark-recapture methods during
November. Population size declined significantly between the winters of...
Since the decline of salmonid populations in the Pacific Northwest, supplementation programs have become frequently implemented by hatcheries as a way to protect and conserve wild stock. However, hatchery-reared fish have lower fitness than wild fish which is likely due to adaptation to the hatchery environment, i.e., domestication selection. Fish...
Amendments and fertilizers applied to optimize crop production and improve soil health also supply inputs of soil organic matter (SOM) and nutrients that affect soil microorganisms. In the dairy-intensive Pacific Northwest, dairy manure is stored as slurry mixtures until conditions are appropriate for soil application. During storage, the manure begins...
Environmental scientists, land managers, and policy actors are increasingly presented with high-stakes high-uncertainty problems stemming from human-ecosystem interactions. To help address these problems, scientists frequently use models that produce enormous geospatial and temporal datasets that are constantly modified and often seek input from communities outside their discipline. To assist scientists—as...
Global biodiversity decline is primarily driven by habitat loss. Deforestation, the primary driver of terrestrial habitat loss, is increasing worldwide, with the most significant impact in the world biodiversity hotspots. Sadly, specific knowledge of such impacts in biodiversity-rich but data-poor countries are still unknown, and many national and regional narratives...
This is a Ph.D. dissertation for a study conducted at OSU/Horticulture. The main objective of this study was dissecting the genetic background for white mold resistance in common (snap) bean. Tow main approaches were followed to achieve the goal. The first approach was using the classical quantitative trait loci (QTL)...
Communities across the American West face new challenges in water management: historical management structures devised to prioritize economic uses, predominantly agriculture, are being tasked with adapting to address growing and changing populations, unaddressed species and ecosystem needs, and climatic changes. Scholars in the field of collaborative governance posit that collaborative...
Central Oregon's landscape is rich in dry forests prone to frequent wildfires. Climate change studies and improved modeling indicate this region could experience conditions that result in an increase in number and severity of wildfires. With the potential for increased environmental hazards, the nearby communities face potential risks and vulnerabilities...
Wheat (Triticum aestivum) is an important crop worldwide, however, in recent years concerns have been raised regarding two health issues, celiac disease and gluten sensitivity, and their relationship to wheat consumption. This increase has led to questions regarding potential changes over time in the composition of gluten (glutenin and gliadin)...
Objectives of this study were to examine effects of dietary pyrrolizidine alkaloids (PA) on copper and vitamin A metabolism in the chicken which are very susceptible to the hepatoxic effects of PA and Japanese quail which are highly resistant to PA. Also, the possible interaction between copper and vitamin A...
In 1987, Congress authorized a 5 year $150 million dollar research program called
the Strategic Highway Research Program (SHRP). SHRP was divided into four major
areas, including the asphalt research program. The asphalt research program was divided
into six major research contracts, one such contract, SHRP-003A was called Performance
Related...
Understanding the dynamics of open marine populations is difficult. Ecological processes may vary with the spatial structure of the habitat, and this variation may subsequently affect demographic rates. In a series of observational and experimental studies in the Bahamas, I examined the roles of emigration, mortality, and predation in the...
Research was carried out to determine the influence of increasing
the percentage base saturation of the soil on the yield of
the commercial strawberry. It was found that the effect of increasing
the bases in the soils was directly related to the original
percentage base saturation. When this original value...
Acoustic scanned holography is a method of lensless photography
which uses sound waves to construct the hologram and light waves to
reconstruct the image. The receiving transducer scans a plane area
containing the sound field generated or scattered from the objects. In
simultaneous source receiver scanning, both the source and...
Epichloë typhina (Ascomycetes: Clavicipitaceae) is an endophytic fungus that
infects perennial Pooid grasses and is the causal agent of choke disease. It is endemic
to Europe and was inadvertently introduced into orchardgrass seed production fields in
western Oregon. Choke disease, which was first recorded in Oregon in 1996, currently
infects...
The research presented in this dissertation focuses on the model generation and modeling processes of student teams that participate in capstone, undergraduate engineering physical and virtual laboratory projects. The Heat Exchange Laboratory Project, the Ion Exchange Laboratory Project, and the Virtual Chemical Vapor Deposition (CVD) Laboratory Project provide the context...
Knowledge of post-dispersal seed fates and other regeneration characteristics is
crucial for predicting abundances and distributions of populations and, ultimately,
community species composition and diversity. Seed fate studies, however, are rare
primarily due to the difficulty of determining seed fates and causes of mortality.
This thesis investigated post-dispersal seed fates...
Decline in cardiac pump function is a hallmark of aging where mitochondrial decay is an important underlying cause. Although certainly multifactorial in nature, both dysfunction of the machinery involved in the chemiosmotic process of energy transduction and lower capacity to maintain fatty acid-driven respiration are identified as intrinsic factors of...
Experiments were conducted to determine if the plagiotropic
growth habit of rooted cuttings of Douglas-fir might result from a
system favoring the accumulation of indoleacetic acid in the adaxial
side of the shoot in response to vertical placement.
Actively growing excised branch terminals were subjected to
gravitational disorientation to determine...
Pheromones are chemical cues produced by organisms that affect the behavior and/or physiology of conspecifics. The orchestration of reproductive behaviors in many animals depends on the expression of sex pheromones. In insects, intraspecific variation in sex pheromone expression is commonly observed and often influences social interactions between individuals. To what...
Wheat sharp eyespot (SES), caused by the soil-borne fungus Rhizoctonia cerealis is a common stem disease of wheat globally. The disease caused a severe and extensive epidemic throughout the Willamette Valley of Oregon in 2014 and has remained one of the most important wheat diseases in this region. However, litte...
Premature birth interrupts the typical development of the human fetus, leaving the infant born with underdeveloped gastrointestinal and immune systems. Preterm infants have reduced stomach acidity, reduced digestive protease activity, more permeable intestinal membranes, impaired innate and adaptive immune response, and poor microbiome development. Due to these factors, preterm infants...
Nanoparticles (NPs), defined as materials having at least one dimension (height, width, diameter) in the nanoscale, are increasingly being incorporated into a wide variety of products and are replacing traditional bulk materials in many applications. This is because they can be more efficacious, more sustainable, and can have unique characteristics...
The purpose of this study is to investigate the role of the
source of the external trade statistics in measuring the price
responsiveness of foreign demands and relative price competitiveness
of the major exporting countries in trade of agricultural commodities
in international markets. In particular, the papers included in this...
The purpose of the present study has been the specification
and measurement of the characteristics of the intraseasonal demand
for fresh Bartlett pears. In particular, the study has focused
attention on a particular producing area, the Rogue River Valley
of Oregon.
The intraseasonal analysis for fresh Bartlett pears was
performed...
In order to effectively use foodgrain prices as tools of government policy, it is necessary to know the possible effects of price incentives on different economic variables. The present study
attempts to measure the effects of foodgrain prices, upon various economic variables, including production, consumption, both at the farm and...
This study investigated how a minority population of Latino/a immigrant children attending a middle school in the Pacific Northwest made sense of engaging with school and school mathematics. A cross disciplinary theoretical framework was used to examine how individual student motivation is impacted by the social context in which the...
This dissertation re-examines the now standard perceptual model of hillslope
hydrological response to rainfall, which includes the growth of a saturated wedge at the soil-bedrock interface or impeding layer. It also challenges the notion of bedrock impermeability and the assumption that the pattern of subsurface stormflow is determined by the...