The objective of this research was to improve our understanding of how
changes in the environment affect ecological processes. Change detection is often
confounded by the large variation found in ecological data due to the difficulty of
finding replicates in nature. Intertidal communities were chosen for studies of biophysical
interactions...
The intriguing size- and shape dependent properties of nanoparticles have garnered recent attention in many science and engineering areas. When the particle size is in the nanometer size range, the material exhibits very different properties such as surface plasmon resonance (of gold nanoparticles) and superparamagnetism (of iron oxide nanoparticles). The...
Caenorhabditis elegans is arguably the best understood animal on the planet.
Used for over 50 years to study development, we have a vast amount of knowledge of
the inner workings of this worm. Our knowledge is incomplete, however, without
placing this organism in its evolutionary and ecological context. In this...
Changes in climate caused by increased concentrations of carbon dioxide (CO₂) in the Earth’s atmosphere have led land and ocean surface temperatures to increase by 0.85°C and sea level to increase by 19 cm relative to preindustrial times. Global climate change will lead to further alterations in mean temperature and...
Grasslands in the Pacific Northwest are characterized by seasonally wet, acidic soils that mainly support cool season grasses and a limited number of legume species. A major limitation to efficient animal production in grass-dominant pastures is the decline in the herbage growth rate and nutritional quality of forage from late...
During barley germination, α-amylase and other hydrolases are synthesized in the aleurone layer and secreted into the starchy endosperm. As starch is degraded by amylases, lysophospholipids are released from inclusion complexes with the starch and undergo hydrolysis by a lysophospholipase (LPL) activity. Studies with embryo-free half seeds and isolated aleurone...
The capability of the marine red macroalga Portieria hornemannii to remove and detoxify the nitroaromatic explosive 2,4,6-trinitrotoluene (TNT) in a seawater environment was evaluated using an axenic microplantlet suspension culture system. Microplantlets were challenged with TNT dissolved in seawater at concentrations of 1 to 50 mg L-1 in well-mixed photobioreactors...
The objective of this dissertation is to examine federally administered soil conservation policy within the United States and the broadly defined Columbia River Basin in the US Northwest. I accomplish this in five chapters. In the first chapter I provide background information for the study. In the second chapter I...
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...
Biological hydrogen production from renewable feedstocks was reckoned as a promising method for sustainable energy production. Bioelectrochemical hydrogen production using microbial electrolysis cells (MECs) demonstrated superiorities over the conventional methods for hydrogen production. The introduction of the membrane-less single chamber design further improved the feasibility of MECs for practical application,...
Reintroduction programs are increasingly being used to save animals from extinction and aid in their recovery. The California Condor (Gymnogyps californianus), one of the most endangered birds in the world, is a remarkable example of how reintroduction programs can help rapidly increase a species' population numbers and range following a...
Agricultural practices influence the nutrient dynamics of soil and plants, which may take more than a decade to be expressed in the drylands. The nutrient supplying capacity of soil is a crucial component of sustainable agriculture, and hence, this study can play an important role in policy making for the...
The symbiosis between cnidarians, such as corals and sea anemones, and photosynthetic dinoflagellates belonging to the genus Symbiodinium spp. is one of the most productive in the marine environment. This mutualistic endosymbiosis allow reef-building corals to lay down the foundation of coral reef ecosystems, which supports a highly biodiverse community...
Internally-pH-controlled, phosphate containing and non-phosphate
containing Italian bulk starter media were compared to
reconstituted nonfat dry milk and commercial bulk starter media
for their ability to support the growth and activities of
commercially frozen thermophilic lactic acid cultures. Cultures
grown in internally-pH-controlled media demonstrated superior
acid-production capability. The cheese made...
Determination of the source and fate of natural (higher plant lipids, marine
lipids, etc.) and anthropogenically (e.g., petroleum, coal emissions) derived
hydrocarbons and oxygenated compounds in the environment was accomplished
using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS)
to characterize or identify molecular biomarkers to be utilized as tracers....
Zoos, aquariums and other free-choice/informal education settings offer the public opportunities to interact with live animals in exhibits through animal encounters and/or touch experiences designed to carry a conservation mission. Many of these institutions are accredited by the American Association of Zoos and Aquariums (AZA) and the World Association of...
Aroma is one of the major components that determines the quality of wine and consumer acceptability. Fruitiness is a highly desirable aroma quality in white wines and has been well accepted by consumers across the globe. Tropical fruit aroma has been substantially studied in Sauvignon Blanc wines due to its...
This dissertation is informally divided into three major sections. In the first section (Chapter 2) I use data from field mapping, isotopic geochronology, whole rock geochemistry and trace element concentrations in zircons to examine the petrology, geochemistry and ages of the Haquira East porphyry copper deposit of southern Peru. In...
Anthropogenic land-cover change and climate change are the major drivers of the steep loss of avian biodiversity in past decades. Loss of avian biodiversity is predicted to result in the reduction of ecosystem services and ecological functions. Identifying avian population changes and the drivers of these trajectories is essential for...
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...
The potential for nanomedicine to reduce toxicity and improve therapeutic response to radiation is vast. Clinically, this potential has thus far only begun to be realized with the recent success of the radioenhancing nanoparticle, NBTXR3 by Nanobiotix. Radioenhancing nanoparticles, however, represent only a small class of nanomaterials that may be...
Modeling of hydraulic fracturing wastewater treatment systems must be very accurate so it can be used for real-time modeling and control of the process. The treatment of hydraulic fracturing wastewater is complex because of the variability of the composition of hydraulic fracturing wastewater. In this work, literature review of hydraulic...
Substantial research on the functionality of athletic apparel has been conducted; however little consideration has been given to the plus size figure. Societal messages suggest that overweight women are lazy and therefore would not be interested in athletic apparel. The purpose of this study was to determine overweight adult women's...
The 2-ka eruption of Misti volcano produced voluminous flowage deposits and a wide-spread tephra-fall deposit. The flowage deposits form large terraces within channels draining the south side of the volcano. All the channels drain into the city of Arequipa. Arequipa's city center is ~16 km from the summit of the...
Proteolytic degradation of fish flesh occurring at elevated temperatures is the
primary limitation for the commercial utilization of arrowtooth flounder (ATF).
Characterization of the autolytic activity of ATF muscle incubated at various pHs
and temperatures indicated the involvement of heat-activated proteinases active at
acidic and alkaline pHs. Further characterization of...
Due to a growing body of literature documenting declines in pollinator populations, there has been increased public interest in pollinator conservation. In urban and suburban landscapes, many gardeners and urban land managers are interested in gardening for pollinators, particularly bees. Simultaneously, many homeowners and municipalities are interested in other aspects...
Vegetation ecology of eight Oregon freshwater wetlands was
described and net aerial primary productivity estimated in four
wetlands. Plant cover samples were used to classify 37 wetland and
11 terrestrial communities by agglomerative hierarchical clustering.
Samples and species were ordinated. Direct measurements were made
of sample relative elevation, inundation duration,...
The dynamics of stands in the mid-elevation old-growth
Douglas-fir (Pseudotsuga menziesii) forests of the central western
Oregon Cascade Range were investigated using stand structure
analysis. Trees with different growth rates were commonly present
in the same stand, which resulted often in a weak correlation
between tree diameter and age. Thus,...
The causes of the global biodiversity crisis are varied and complex. Anthropogenic threats may act in isolation, or interact additively or synergistically with each other or with natural stressors to affect sensitive taxa. The recent emergence of many infectious diseases in wildlife has brought attention to the role of disease...
Rift Valley fever (RVF) is a mosquito-borne zoonotic viral disease native to the African continent. Outbreaks tend to occur in the wet seasons, and can affect numerous mammalian species including African buffalo. It is debated how the virus survives the inter-epidemic period when it is not detected in mammalian populations,...
Despite the advances in surgery, physical therapy, and pharmaceutical agents, muscle
dysfunction (i.e., atrophy and weakness) continues to impair recovery from an anterior
cruciate ligament (ACL) injury and surgery. Ischemia-reperfusion injury during surgery
and the subsequent limb disuse are two events experienced by patients having ACL
surgery. Oxidative stress and...
Brown marmorated stink bug (BMSB), (Halyomorpha halys, Hemiptera: Pentatomidae) is an invasive species that damages numerous agricultural crops including grapes. Related damage include lower berry weight with increased exposure and cracked berries as a result of BMSB feeding activity. The insect is currently detected in 43 US states including Oregon,...
Oxidative stress is the major driving force behind the aging process and many age-related diseases. However, direct experimental evidence of whether antioxidants, such as ascorbate (AA) and lipoic acid (LA) can slow the progression of aging process and/or reduce risks of developing degenerative disease is largely absent. This suggests a...
The federally threatened northern spotted owl (Strix occidentalis caurina) is the focus of intensive conservation efforts that have led to much forested land being reserved as habitat for the owl and associated wildlife species throughout the Pacific Northwest of the United States. Recently, however, a relatively new threat to spotted...
Knowledge of regional-scale patterns of plant community structure and controlling factors is largely qualitative and based on numerous local studies. Data from a subsample of 10,000 field plots were used to quantify and map compositional gradients of woody plant communities across Oregon forests. Canonical correspondence analyses explained 9-14% of the...
Millions of children are exposed to various types of violence throughout their school years. American children, by the time they are 18 years old, have seen more than 100,000 acts of violence on television alone. The effect of exposure to violence becomes a part of a child's life experience and...
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 western Nearctic species of the genus Phytocoris Fallen were
taxonomically revised. Over 15,000 specimens were examined.
Information concerning host plant associations and distributions was
compiled and summarized for use by future researchers. External
morphological features and characters of the male genitalia were used
to distinguish species. The genital tubercles...
Managers of forest and plantation ecosystems are encountering growing problems involving plant pathogens and the expanding geographic ranges of these pathogens. Historically unexposed stands are exceptionally vulnerable when a non-native pathogen is introduced because these pathogens can cause devastating disease in a host population that lacks co-evolved resistance mechanisms. One...
The genus Lopidea Uhler is revised for America north of
Mexico. The relationship of Lopidea to other orthotyline
genera is discussed and it is proposed that the genus
Ilnacora Reuter is the sister group of Lopidea.
Forty-eight species of Lopidea are recognized in North
America, one of which is described...
At a time when the biodiversity on Earth is being rapidly lost, new technologies and methods in genomic analysis are fortunately allowing scientists to catalog and explore the diversity that remains more efficiently and precisely. The studies in this dissertation investigate genomic diversity within the milkweed genus, Asclepias, at multiple...
Replication associated protein and enzyme activity levels increase as cells enter
S-phase of the cell cycle and diminish as cells leave S-phase. Accordingly, replication
associated functions decrease as myoblasts withdraw from the cell cycle to terminally
differentiate. In an effort to understand signals effecting growth associated expression
of genes, the...
A study was conducted to determine effects of year and season on diet quality of beef cattle grazing northern Great Basin rangelands from 1990 to 1993. Forage quality was high early in the growing season, then declined as seasons progressed (P<.05). Plant chemical composition was higher early in the growing...
The field of toxicology is challenged with a vast number of environmental chemicals and mixtures to which humans and ecosystems are exposed with limited toxicity data available. Chemical hazard assessment traditionally utilizes mammalian models and can be both cost- and time-limiting and may pose ethical concerns. To rapidly tackle this...