The design considerations for fast-settling operational
amplifiers (opamps) differ significantly between sampled-data switchedcapacitor
(SC) and conventional continuous-time applications. In SC
circuits, the shape of the output voltage waveform of an opamp is of no
consequence provided that the output settles to within a specified
tolerance of its steady-state value prior...
Vertisols and other vertic-intergrade soils are found all over the globe, including many agricultural and urban areas. These soils are characterized by their cyclical shrinking and swelling behaviors, where bulk density and porosity distribution both vary as functions of time and/or soil moisture. In turn, alterations in physical soil parameters...
In recent years, studies dealing with temperature regulation,
temperature sensitivity, and physiological responses to temperature
in lizards and other reptiles have increased tremendously. It is
notable that snakes have been largely ignored in such studies. This
no doubt is due to their less direct relationship to ancestral endotherms.
However, problems...
Investigations were conducted to determine the nature, type,
functional properties and the amounts of different proteins found in
bovine rumen tissue.
Data concerning the effect of pH and salt concentration on
the extractability of proteins from rumen tissue indicated that 92%
of the proteins could be extracted in aqueous solutions...
Spores of Equisetum were germinated and the resulting
gametophytes grown to maturity in standard microcultures. Light and
electron microscope observations were made of the chloroplasts
within the gametophytes.
These chloroplasts were found to be oval to dumb-bell shaped
organelles possessing organized grana. By means of time-lapse
movies they were shown...
Samples of pre-rigor sternomandibularis muscle from ten
steers were pressurized at 15,000 psi for two min at 35°C to investigate
the effects of pressurization and incubation time on
the thermal stability of collagen. Immediately after pressurization,
pH of the treated samples (pH 5.71) was significantly lower
(P < 0.05) than...
Studies were conducted to determine the post-mortem stability
of lysosomes in the white muscle of rainbow trout (Salmo gairdneri)
and to determine whether lysosomal stability was related to rigor
mortis and its subsequent dissolution. In addition, isolated lysosomes
were subjected to different environments in an attempt to detect some
of...
The agricultural industry across the United States is experiencing a shortage of qualified and interested young professionals who aspire to enter the agricultural sector. Internships have largely been used as an effective hands-on learning tool, exposing college students to an array of occupational skills and expectations in hopes of creating...
The purpose of this study was to explore and describe how the orientations and knowledge of linguistically responsive teaching, as well as personal characteristics of school-based agriculture education (SBAE) teachers, influence the frequency of their implementation of linguistically responsive practices. Grounded in the Linguistically Responsive Teaching framework by Lucas and...
Sisson's formally exact series solution for momentum, heat and
mass transfer in steady two-dimensional or axi-symmetrical constant-property,
laminar boundary layer flow was examined. A new series
was proposed for the boundary condition accounting for the mass
transfer at the surface of the body on which the boundary layer is
formed....
The processes responsible for transporting and depositing thick
sections of coarse-grained terrigenous clastics on the abyssal floor
and for forming associated sedimentary structures are still conjectural.
Many workers attribute coarse deep-sea sediments and their
probable lithified equivalent, the graywackes of flysch deposits to
some type of density movement.
Deductions concerning...
Two studies were conducted to determine the in vitro metabolic and hormonal effects on glucose 6-phosphate dehydrogenase activity (G6PD) in bovine mammary explants. Study I was conducted to determine the effects of palmitoyl CoA (5 and 25 uM), acetate (1 and 10 mM), spermidine (0.4 mM) and putrescine (0.4 mM)...
Herein, a program of research is detailed related to transport through the Si metal oxide semiconductor (MOS) quantum dots fabricated in a process flow compatible with modern ULSI (ultra large scale integrated circuit). Silicon quantum dots were fabricated by placing split gates within a MOSFET structure. Quantum dots of several...
Oregon is a state with great social and ecological diversity. Unfortunately however, Oregon's water-rich reputation is more rumor than reality. As with many Western states, Oregon struggles with water scarcity, especially during dry summer months. Recent efforts by the state to develop an integrated water resource strategy (IWRS) to manage...
Oral administration is the most practical way of vaccination of fish. It has advantages over intraperitoneal injection and immersion methods that include no stressful handling, no interference with routine fish husbandry and antigens can be delivered to the fish in their feed.
An oral antigen delivery system was developed for...
In the western United States, bighorn sheep (Ovis canadensis) have suffered major die-offs in every state since the mid-1800s, and disease from domestic sheep (Ovis aries) has been a primary factor in these events. Beginning in the early 1900s, poly-factorial, poly-microbial pneumonia was identified as a major disease affecting bighorn...
Seed shattering is a constraint to improvement of seed yield in Lolium perenne L. and as a result, seed retention is an essential trait for this valuable crop. Field studies were conducted near Corvallis, OR in two years (2017-2018 and 2018-2019) to identify genetic variation for seed retention and to...
Phytoplankton are a sentinel class of organisms in the marine environment. Through their photosynthetic activity in sunlit waters worldwide, phytoplankton shape the health and productivity of marine ecosystems and impact the global climate. In this work a range of ocean sensing technologies (via ships, surf zone sampling, moorings, gliders, and...
The primary objective of this study was to develop a prototype
instrument of procedures and criteria to be used by community college
s for self-analysis and evaluation purposes. The study grew out of
the recognized need to assess and improve the effectiveness and pertinence
of community college philosophies, roles and...
Drought and mandatory water restrictions are limiting the availability of irrigation water in many important blueberry growing regions and new strategies are needed to maintain yield and fruit quality with less water. Three potential options for reducing water use, including deficit irrigation, irrigation cut-offs, and crop thinning, were evaluated for...
Coral reefs form vast ecosystems in tropical oceans that are hotspots for biodiversity and are economically valuable. The ecological success of coral reefs is made possible by the symbiotic relationship between corals and dinoflagellate algae from the family Symbiodiniaceae. In this symbiosis, the algae are found within host gastrodermal cells...
As part of investigations to adapt a suitable grazing system in
western Oregon, this research was designed to monitor the effects of
defoliation treatments on dry matter production, forage quality,
regrowth after defoliation, and species composition of a Lolium
perenne Trifolium subterraneum pasture for three consecutive
growing seasons from 1980...
Parasitological and selected microbiological safety aspects
of Nham (Thai-style fermented pork sausage) were evaluated. Pork
meat from pigs experimentally infected with Trichinella spiralis
was divided into 4 portions; 3 portions were frozen at -23°C for
12, 18 and 24 hours before they were made into Nham. The formula
for fermented...
Continental shelves located along eastern boundary currents occupy relatively small volumes of the world’s oceans, yet are responsible for a large proportion of global primary production. The Oregon coast is among these ecosystems. Recent analyses of dissolved oxygen at shallow depths in the water column has suggested increasing episodes of...
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...
Toxin production by cyanobacterial harmful algal blooms (cyanoHABs) in freshwater systems has lasting ecological and human impacts. Nutrients, light availability, hydrology, and microbial community composition impact the frequency and intensity of toxic cyanoHABs. Climate change will exacerbate toxic cyanoHABs, making real time and predictive monitoring a vital tool for managing...
Influence of abiotic and biotic factors were examined in selected
winter wheats previously identified as representing a range of
responses to septoria infection. In the greenhouse two and three
inoculations identified resistance when disease severity was assessed
either for the top four leaves or the flag leaf respectively. Kernel
number...
The purpose of this study was to explore how campus climate at Hispanic-Serving Institutions (HSIs) influences degree completion for Black women. As the number of HSIs has increased in the past decade, there exists a need to understand how Black women fare in such an institutional context. Though there is...
The importance of physical activity is well documented (Haskell et al., 2009a; McReynolds & Rossen, 2004; Steinbeck, 2001). Despite physical activity’s benefits, many individuals are not meeting current weekly physical activity guidelines recommending ≥ 150 minutes of moderate or ≥ 75 minutes of vigorous aerobic physical activity and 2 or...
Approximately half of the 6.4 million pregnancies occurring each year in the
United States are unintended (Finer & Henshaw, 2006). Unintended pregnancies, defined
as pregnancies not wanted at the time conception occurs, regardless of contraceptive use
(Chandra, Martinez, Mosher, Abma, & Jones, 2005) can have serious repercussions on
women, children,...
The effect of increased manganese superoxide dismutase (Mn-SOD) and cytosolic ascorbate peroxidase (cAPX) on various abiotic stresses was studied using transgenic tomato (Lycopersicon esculentum) plants. Transformants were selected in vitro based on kanamycin resistance, confirmed by PCR and northern blot analyses. Northern blots showed an enhanced gene expression of Mn-SOD...
Blue spruce (Picea pungens) and Engelmann spruce (Picea engelmannii) experience varying levels of spruce beetle (Dendroctonus rufipennis (Kirby)) colonization, yet the underlying differences and mechanisms resulting in lower colonization for blue spruce are not known. Both spruce species have important roles in subalpine ecosystems where examining changes in mortality, distribution,...
Since its inception as a laboratory animal in the early 1970s, the zebrafish has proven itself a rising star in the world of comparative biomedical sciences due to its short generation time, ease of care, external fertilization, and transparent larvae. In a very few decades, the zebrafish has been utilized...
A proposed state-and-transition model (STM) for the Deep Sand Savannah ecological site in central New Mexico was developed using historical data and expert knowledge. This STM was tested utilizing data from short and long term one-seed juniper (Juniperus monosperma (Engelm.) Sarg.) control experiments initiated in 1981 and 1985. Utilizing data...
Modern plant pathology benefits from integrating methods and concepts from evolutionary biology. For example, evolutionary concepts are used to identify and examine species boundaries of plant pathogens, recognize processes underlying pathogen biogeography, identify traits that characterize emerging species, and discover new molecular interactions that originate under processes of selection. In...
Two mathematical computer games, POE and EQUATIONS, were used to
test the effects of games as learning aids in a university entry-level
intermediate algebra course. Specifically, this study investigated
whether use of these games would significantly increase student achievement
in the course and improve student attitude toward mathematics.
EQUATIONS is...
A primary goal of population genetics is to identify the role of
microevolutionary forces in producing observed patterns of molecular and phenotypic
variation. I conducted four studies in the northern leopard frog, Rana pipiens, to
determine just how mutation, migration, genetic drift, and selection influenced,
genetic structure of mitochondrial DNA...
The primary question to be answered as a result of the
research was: Do native English-speaking undergraduate
students learn CD-ROM database search skills more
effectively through the use of conventional instruction
method or by training confined to a written manual self-instructional
method? Thirty-seven Oregon State
University students were randomly assigned...
The major nutrient requirements of the blue-green alga Anabaena
spiroides Klebahn were investigated. It was hoped that the results would allow the development of a balanced culture medium in
which the alga would exhibit rapid growth and retain typical morphological characteristics.
The alga was isolated from Upper Klamath Lake, Oregon,...
Diversity and inclusion represent central challenges and opportunities in the transnational field of higher education, as the number of students enrolled in higher education has expanded exponentially over the past century and universal access to tertiary education has emerged as a development imperative. Within this context, diversity has emerged as...
The microsporidian parasite, Pseudoloma neurophilia, is the most commonly diagnosed infectious disease in laboratory populations of the zebrafish, Danio rerio. Infections by P. neurophilia are generally subclinical, however, they can become acute either incidentally or due to experimental immune suppression. Non-protocol induced variation can confound results in laboratory experiments using...
Fennema and Sherman (1976) defined math anxiety as "feelings of anxiety, dread, nervousness, and associated bodily symptoms related to doing mathematics" (p. 326). The longitudinal impact that math anxiety has on adolescent students can include their experiencing reduced math achievement, avoiding majors that involve large amounts of math, and choosing...
Stable expression of transgenes is required for commercial uses of genetically engineered trees. To better understand the stability of transgene expression under field conditions, we studied transgene expression and RNA interference (RNAi)-induced transgene suppression in 2,480 transgenic poplars (460 transgene insertion events) over three years. Stability of expression was assessed...
Inflorescence necrosis (IN) is a recently described disorder in grapes
characterized by partial or complete deterioration of the pedicel and rachis near
bloom. Elevated levels of ammonium in the rachis are associated with the
incidence of IN and hypothesized as the cause of the disorder. An incubation
system with single-node...
This study was an experimental investigation of two methods of
teaching students the cognitive knowledge and psychomotor skills pertaining
to the automobile brake system. The methods investigated
were the experimental individualized learning system and the traditional
group-lecture and demonstration.
Experimental Design and Procedure
The experiment, conducted during the spring term...
In order to develop three models for use in quantifying the
environmental conditions of reforestation, extensive measurements
required for energy balance calculations were taken for a
reforestation site in southwest Oregon. The models are used to
decrease the number of measurements required to properly evaluate
the potential for heat or...
Corporate universities (CUs) have been in existence in the United States since the early 1900s. They are increasingly providing educational and developmental opportunities for workers; however, there is little empirical research on these types of organizations. This study examined a specific electrical distributor's CU using a theoretical framework as a...
Experiments were conducted to characterize the nongenomic effects of
progesterone (P4) on binding of oxytocin (OT) to the ovine oxytocin
receptor (OTR) and signal transduction. The dose-response relationship of
P4 to OT binding to the OTR in endometrium was examined. Progesterone
interfered with the binding of OT to the OTR...
The location of prune dwarf virus (PDV) and Prunus
necrotic ringspot virus (PNRSV) in pollen and seed
from infected and healthy sweet cherry trees pollinated
with infected pollen was investigated. Virus-like
particles were observed in the cytoplasm of pollen
grains from PDV-infected cherry trees using transmission
electron microscopy. No particles...
Forests play an integral role in the global carbon cycle, regulating the atmospheric CO₂ concentration by sequestering nearly one third of anthropogenic carbon emissions and storing carbon for centuries. Forest ecosystems are integrated into the culture, ecology, and economy of western North America, supporting wildlife habitat, local economies, recreation, and...
Statement of the Problem
The primary purpose of this investigation was to determine
if a valid and reliable assessment instrument could be
developed to measure the cultural competence of counselor
trainees.
Hypotheses
Five hypotheses were generated to establish the reliability
and validity of the instrument. The instrument consisted
of two...
The impact that pesticides may have had on the mortality rates and productivity rates of non-game birds during the last 25 years was evaluated by studying the population dynamics of 16 species. A mathematical model showing the relationships between population parameters that yielded stable populations was developed. The information needed...
Mycobacteriosis is a common disease of laboratory zebrafish (Danio rerio). Different infection patterns occur in zebrafish depending on mycobacterial species. Mycobacterium marinum and M. haemophilum produce virulent infections associated with high mortality, whereas M. chelonae is more wide spread and not associated with high mortality. Identification of mycobacterial infections to...
At a time when environmental conditions are rapidly changing, understanding how thermal extremes impact wildlife is imperative to fully understanding the consequences of climate change in natural ecosystems. While many organisms are currently impacted by rapidly warming and more erratic environmental conditions, identifying and investigating model species whose life histories...
The plant Senecio jacobaea (tansy ragwort) produces several macrocyclic pyrrolizidine alkaloids which cause irreversible liver cirrhosis. All of the pyrrolizidine alkaloids in Senecio jacobaea are macrocyclic diesters of the necine base retronecine, with the two most predominant being seneciphylline and jacobine. Unlike horses and cattle, sheep and goats are generally...
In this study I discuss the state of Free-Choice Learning research, and an investigation into the use of personal ubiquitous technology on visitors' experiences at a science center. The three manuscripts included in this document:
1. Review published research on free-choice learning from 1997-2007 from selected journals
2. Examine visitors'...
The enzymes of dNTP synthesis in T4 infection associate to form a multienzyme complex, the T4 dNTP synthetase complex, facilitating the flow of metabolites en route to dNTPs, and their subsequent flow into DNA. Study of protein-protein interactions helps one to understand how the enzymes in the complex are organized...
Two native shrub species (Piliostigma reticulatum and Guiera senegalensis) are prominent vegetation components in farmers’ fields in Senegal. However, their role in nutrient cycling and ecosystem function has largely been overlooked. A study including both laboratory and field experiments was conducted to evaluate potential biophysical interactions of the two shrub...
Parasitic infections and immune challenges can affect host reproductive fitness and, ultimately, the evolution of host populations in a myriad of ways. The fitness implications of parasitic infections range from increased host mortality to subtle changes in reproductive investment. From alterations of behaviors, sexual signaling, and competitive ability to changes...
Climate change impacts everyone’s food and water security. Increasing global temperatures accelerate the hydrologic cycle and consequently impact the water resources for billions of people worldwide. Countless models have been developed to represent various components of the hydrologic cycle at various spatial and temporal scales. These are often validated against...
This dissertation integrates a process-based hydrological investigation with an
ongoing paired-catchment study to better understand how forest harvest impacts
catchment function at multiple scales. We do this by addressing fundamental questions
related to the stocks, flows and transit times of water. Isotope tracers are used within a
top-down catchment intercomparison...
A saprozoic nematode, Diplogaster lheriteiri Maupas 1919,
was studied to determine its relationship to the plant pathogenic bacteria,
Agrobacterium tumefaciens (Smith and Townsend) Conn.,
Erwinia amylovora (Burrill) Winslow et al., Erwinia carotovora
(Jones) Holland, Pseudomonas phaseolicola (Burk. ) Dows.,
Xanthomonas campestris (Pam. ) Dows. and to a phage of A....
Two Oregon reservoirs contaminated by different mercury
sources were compared for mercury distribution in sediment and
bioaccumulation by fish. The average mercury concentration in
the sediment of Cottage Grove reservoir (0.67 ± 0.05 μg/g dry
wt) was higher than for Dorena Reservoir (0.12 ± 0.01 μg/g dry
wt). Sediment mercury...
The two studies of this dissertation examined mothers' perspectives of nonresident fathers' involvement in low-income families. The overall goal of these studies was to gain a more comprehensive understanding of nonresident fathers' involvement and its effect on family well-being. In the first study I applied a relatively new methodology, zero-inflated...
Biological plant invasions are diminishing the ecological integrity and function of ecosystems worldwide. A primary example of this is in the Great Basin of the United States, where invasive annual grasses, like cheatgrass (Bromus tectorum L.) and medusahead (Taeniatherum caput-medusae L. Nevski), are dominating many sagebrush-steppe ecosystems. In these invaded...
The first goal of this study was to understand the role of calpains in skeletal muscle
protein degradation in cultured cells. We have developed a genetic approach to inhibit
endogenous calpain activity through over-expressing dominant negative m-calpain (DN),
antisense m-calpain (AS) and calpastatin inhibitory domain (CID). We observed that,
under...
The global cryosphere, defined as the world’s ice and snow covered regions, is a crucial water source for society and ecosystem functions, as well as an important regulator of the earth’s energy budget. Melt from glaciers and seasonal snow cover provides water for more than a sixth of the world’s...
Early life stages of many marine and diadromous fish species use sandy beach surf zones, which occur along >50% of the world's marine coastlines. This extensive habitat can provide juvenile fishes with an abundant supply of potential prey and the ability to hide from predators in its shallow turbid waters....
Aromatic Nitro Compounds. The n-values for the reduction of
the isomers of nitrophenol and nitrobenzoic acid and for several
other nitro compounds are determined in dimethylsulfoxide by controlled
potential coulometry. A procedure is given in which one
mole of nitro compound may be determined with errors of less than
one...
The semi-arid sagebrush steppe ecosystem is one of the largest biomes in
North America. The steppe provides critical habitat and forage for wildlife and is
economically important to recreation and livestock industries. However, the ecosystem
is threatened primarily due to several negative effects associated with expansion of the
exotic annual...
A series of field experiments was established in 1978, 1979, and 1980 on Lower Klamath Lake where Mn deficiency of oats had been observed in previous years. The pH of the soils ranged from 7.6 to 8.3 and the organic matter content was between 17 and 19%. The objectives of...
The genus Phytophthora comprises numerous plant pathogens in both natural and managed ecosystems. For Phytophthora spp. that infect roots, dispersal occurs in soil water through a combination of advection and swimming of specialized motile propagules (zoospores). Specific biological and physico-chemical processes, however, remain poorly understood, due to difficulties in studying...
Self-harm is a frightening phenomenon that affects adolescents and young adults all over the world. While non-suicidal self-injury (NSSI) has a high prevalence rate, it is not a new behavior. One of the earliest documented cases of NSSI was in ancient Greece and it has gained popularity amongst adolescents. NSSI...
Emerging infectious diseases in wild animals threaten global biodiversity as well as domestic animal and human health. Their unprecedented increase in conjunction with anthropogenically induced range shifts of endemic pathogens exposes hosts to novel parasite combinations, lending urgency to research on disease dynamics in wildlife systems. In natural populations, hosts...
In the Pacific Northwest (PNW), concern about the impacts of climate and land cover change on water resources, flood-generating processes, and ecosystem dynamics emphasize the need for a mechanistic understanding of the interactions between forest canopies and hydrological processes. A detailed measurement and modeling program during the 1999 and 2000...
Successful ecosystem restoration requires an understanding of the ecological processes directing succession. One of the challenges in the semi-arid grasslands of western United States is replacement of native species by invasive annual grasses. Solutions to this problem require identifying and manipulating ecological processes that direct succession to favor desired vegetation....
Field experiments were established in 1982 and 1983 on a Woodburn silt loam soil (Aquultic Argixeroll) to examine the effect of S fertilizer on dinitrogen fixation and dry matter yield of 10 week-old seedling alfalfa (Medicago sativa L. cv. 'Apollo'). Six levels of S fertilizer (0 to 67.2 kg S/ha)...
A disease of sweet cherry (Prunus avium L.) known as "cherry
rosette" has threatened production of cherries in Oregon. In 1961
this disease was observed in widely separated orchards. Rosette
occurred in isolated trees or in spreading patterns, often from
identified single trees or from one section of an orchard....
Bioremediation in the vadose zone is unpredictable because of poor understanding of factors influencing microbial growth in this environment. A lab-scale experimental system was developed to examine, noninvasively, interactions between microbial growth, water flow, and solute transport in unsaturated porous media. Measurements of microbial colonization, and its impact on hydrology,...
This thesis examines factors limiting understory herb presence and flowering in young second-growth Douglas-fir (Pseudotsuga menziesii) forests on the west side of the Cascade Mountains, Oregon, USA. I studied the belowground effects of canopy trees on understory herbs and shrubs in old-growth forests using trenched plots from which tree roots...
Management of small dams may have profound implications for the health and integrity of small rivers and freshwater diversity. Global indicators suggest future growth in the small hydropower sector, particularly in developing countries. As a renewable energy source, it is often presumed that small hydropower entails fewer and less severe...
Parenting education is a process of providing information to parents on the
challenges of parenting, services available for families, and ideas on how to interact with
children. The federal Even Start family literacy program, designed to increase the
educational opportunities of parents and children, has a strong parenting education
component....
The education (particularly graduate education) of Americans
who were active in astronomical research between 1876 and 1941
is assessed for its effectiveness in preparing the astronomers for
careers in research. This period contains three dynamic changes:
the growth of American astronomy in becoming the world's leading
community of astronomers, the...