Experiments were conducted to study the effect of pore size
distribution on the diffusion of 2, 4-Dichlorophenoxyacetic acid (carbon-
14) through water saturated porous media. Eight size fractions of
glass beads were used representing the porous media. It was found
that as the average particle radius, and hence pore radius,...
In regions where soil temperatures limit plant growth, artificial
soil warming may be an economically feasible practice. This hypothesis
was evaluated in a soil warming experiment near Corvallis, Oregon.
This experiment was prompted by the observation that multiple
use of waste heat discharged in the condenser cooling water of thermal...
To learn more about the role β-galactosidase plays in rate of
acid production in milk by lactic acid bacteria, several lactobacilli
were examined for this enzyme. Cells from different species were
grown in lactose broth to induce β-galactosidase activity. The specific
activities of whole, solvent treated cells, and of cell-free...
Flood plain regulations are one of six major adjustments
used to cope with flood hazard in the United States. This adjustment
was essentially neglected in the national flood hazard policies
until Congress enacted the National Flood Insurance Act of 1968.
The implementation of regulations, as called for in the Act,...
A simple matrix method for the analysis of protein circular dichroism (CD) spectra is presented and used to compute the secondary structure of globular proteins in their native and denatured states. The method uses singular value decomposition and generalized inverse algorithms, and a basis set of CD spectra for proteins...
A number of investigators have proposed equations to predict
the permeability of porous media. Most of their equations are based
on the distributions of the sizes of the various contributing pores in
the medium. Presently the pore size distributions of agricultural
soils are most commonly obtained from soil water release...
The surface wind and stress responses to sea surface temperature (SST) are examined using collocated moored buoy and satellite observations in the Gulf Stream and the eastern equatorial Pacific. Using 17 buoy pairs, differences in the wind speed, 10-m equivalent neutral wind speed (ENW), and surface wind stress magnitude between...
Mice were used to compare the index and elite selection
methods for simultaneous selection of four traits. Selection was
for litter size, birth weight, weaning weight and post-weaning
gain. Progress was evaluated by examining total phenotypic merit.
The standard deviations from the cycle mean for the four traits
were summed...
Interactions between surface winds and meanders in mid-latitude sea surface temperature
(SST) fronts with horizontal length scales of 100-1000 km are investigated
from satellite observations and numerical simulations. Observations from the Sea-
Winds scatterometer on the QuikSCAT satellite show that the magnitude, direction,
curl, and divergence of the surface wind...
One of many important physical properties that must be known
to understand transport phenomena in soils is pore size distribution.
Presently the pore size distributions of soils are most commonly
obtained from soil water characteristic curves. The soil water characteristic
curves are usually obtained by the pressure plate technique.
It...
Freeze/thaw cycles are numerous in agricultural soils of the Pacific Northwest. Potential loss of soil by erosion is high whenever a soil thaws from the surface creating a saturated soil overlying an impermeable frozen layer. Field studies were conducted to investigate the effect of surface residue on soil freezing. Residue...
Forest soils with low bulk densities are often considered less
susceptible to compaction than soils with higher bulk densities. The
objective of this study was to determine if soil strength controlled the
compression of soils with low bulk density. Four soils were selected
for this evaluation. Three of these were...
Two new methods, one of broad specificity and the other of
narrow specificity, were developed for the identification of
agrobacteria. The former method was based on ribosomal antigens
that were common to members of the closely related Agrobacterium
and Rhizobium genera. Antisera to unwashed 50 S ribosomal subunits
from five...
Involvement has been defined and researched by many student affairs professionals and theorists over the past 40 plus years. While many studies have researched the relationship between involvement and a student's academic success, little research has been done that explores what involvement means to them, and the motivations and factors...
Crown gall was found in numerous pecan orchards in Georgia. In
some instances, 60% of the trees were diseased. Galled trees were
less vigorous than noninfected trees. Among the pathogenic
Agrobacterium strains isolated from 18 galled trees from six
counties, biovar 1 strains predominated and most were sensitive to
agrocin...
In 2013, a large upper-ocean thermal anomaly formed in the Gulf of Alaska (GOA) with sea surface temperatures (SSTs) warmer than 4 degrees Celsius above the climatological norm. This warm anomaly persisted for the next three years and has been linked to downstream effects on North American climate and negative...
Tomato seedlings were used to assay the population of A.
tumefaciens in artificially contaminated soil. Aqueous soil suspensions
were applied directly to the wounded stem. The bioassay was
used because not all pathologically important physiological strains
of A. tumefaciens would grow on any of the selective media available.
This method...
A study was made of compounds produced by Agrobacterium radiobacter
strain 84 that are inhibitory to some pathogenic strains of A.
tumefaciens. Agrocins (inhibitory compounds) were partially purified
from large volumes of A. radiobacter strain 84 culture supernatants to
determine (i) if more than one agrocin is produced, (ii) if...
I examine the strong co-variability between the surface divergence and vorticity and how it varies with latitude in the Pacific Ocean using surface vector winds from reanalysis and satellite scatterometer observations. This analysis was motivated in part by a significant correlation between divergence and vorticity over the global oceans that...
The taxonomic status of Microtus canicaudus was compared
with that of a morphologically similar vole, Microtus montanus. Four
means of comparison were utilized: hybridization experiments, comparative
karyology, growth distinctions (total length and body weight),
and qualitative behavioral observations. The hybridization experiments
indicated that, while the incidence of pregnancy of M....
Surface meteorological data collected at a mesonetwork in
Colorado during the 1973 National Hail Research Experiment were
analyzed to see if a diurnal oscillation of boundary layer wind exists
and also to determine the mechanism that drives the wind system.
The average temperature, pressure, and wind velocity for a month's...
Multiple use of waste heat from power plants may become an
important consideration in the development, siting, and certification
of these plants. A multiple use system of components that can
beneficially utilize waste heat may include home heating and cooling,
greenhouses, animal enclosures, open basins for single cell protein
production...
The major objective of this study was to determine why certain
winter wheat cultivars, when hybridized, will produce a greater proportion
of desirable plants in subsequent, segregating generations.
Three winter wheat parents were chosen as the experimental material,
based on their known performance as parents. Yamhill and
Pullman Selection 101...
Selenoprotein W (SeW) is a protein whose function is unknown, but potentially plays a vital role in calcium metabolism, as an indirect link has been established with white muscle disease (WMD). White muscle disease occurs in selenium deficient animals, and is characterized by the precipitation of calcium in muscle, leading...
This study concentrates on analysis of LongEZ aircraft data taken offshore of the Atlantic Coast of the United States. Due to the land structure of the region, it was possible to isolate the effect of narrow land on air as it flows offshore. The narrow land (Outer Banks) separates inland...
Several large-scale marine heatwave events occurred during the last 10 years in the North Pacific. A particular extreme marine heatwave in the North Pacific called the blob created an unprecedented high peak of sea surface temperature (SST) during 2013/14. MHW events had significant impacts on downstream weather and precipitation patterns...
The purpose of this study is to examine the role of a Filipino American college student organization at a Predominantly White Institution, and uncover elements of the organization that influence or limit the development of critical consciousness of its members. This study focuses on the aspect of critical consciousness that...
One hundred seventy-eight Agrobacterium isolates, 120 United
States (U.S.), 26 Australian and 32 of miscellaneous origin, were
characterized for their reactions to 20 biochemical and physiological
tests. Isolate pathogenicity and degree of host specificity, utilization
of nopaline and octopine, and sensitivity to agrocin-84 also were
determined. The U.S. isolates were...
Gamma-gamma directional correlations were measured
in Ba¹³⁴ at ten angles between 90 degrees and 180 degrees in ten
degree increments using a scintillation spectrometer. The spectrometer
which used NaI crystals, differential energy selection,
and standard coincidence techniques was tested by measuring the
directional correlation of the two cascade gamma rays...
The effect of a static quadrupole interaction on the 133-482 Kev
gamma-gamma angular correlation in Ta-181 has been studied by the
delayed coincidence method. Using a source of Hf-181 in polycrystalline
hafnium metal, the anisotropy was measured as a function of
time between the formation and decay of the 482...
Petroleum mulch applied on the soil surface over a row of
planted seeds promotes a more rapid and a more uniform germination
of seeds, enhances elongation of seedlings and in some cases increases
the yield of the crop. The beneficial effects of petroleum
mulch have usually been attributed to increased...
The stability of steady-state solutions of the equations governing two-dimensional,
homogeneous, incompressible fluid flow are analyzed in the context
of shear-flow in a channel. Both the linear and nonlinear theories are
reviewed and compared. In proving nonlinear stability of an equilibrium,
emphasis is placed on using the stability algorithm developed...
The use of efficient basis functions to model and represent flows with
internal sharp velocity gradients, such as shocks or eddy microfronts, are
investigated. This is achieved by analysing artificial data, observed atmospheric
turbulence data and by the use of a Burgers' equation based spectral
model. The concept of an...
Several horizontal flight segments from SESAME and
ALPEX are studied using structure functions and specral
analysis methods. Theoretical analysis of the relative
errors in structure function and correlation function in
the presence of large scale wave activity is presented. The
effect of stratification and shear on the -5/3 inertial
subrange...
An eigenvector analysis of the velocity-temperature correlation
matrix is applied to clear-air turbulence measured by aircraft in the
Bora. The eigenvectors are identified with the main eddies of the
turbulence. This study attempts to infer the three-dimensional
structure of these eddies. The results are compared with turbulent
structures in the...
The purpose of this study was to determine the importance and
the frequency of use of certain communication skills to job-entrylevel
mechanics as assessed by employers, educators at various levels,
and entry-level industrial mechanics. The study was conducted in
Lane County, Oregon. Communication skills investigated for importance
and for frequency...
The purpose of this study was to use computer analysis of soil and rainfall data to predict the possible occurrence of soil erosion in Central Tunisia. Analysis was done with the program OR-NATURE (M.Ungs et al, 1985) . Central Tunisia was subdivided into northern, central, and southern subzones. Data about...
The very stable boundary layer is a region of the atmosphere typified by large
vertical gradients of temperature and momentum. Analysis of very stable atmospheric
flows is complicated by the presence of nonlinear interactions among gravity waves, shear-driven
overturning circulations, two-dimensional vortical modes and intermittent turbulence
in various stages of...
The purpose of this study was to determine the concerns of past participants of the Summer Agriculture Institute regarding the use of agriculture as a context for teaching and to determine how they implement curriculum integration. The study used the Concerns-Based Adoption Model as a theoretical framework, which resulted in...
Gaseous diffusion equations which describe the diffusion of
oxygen and carbon dioxide through soil have been studied by several
investigators. However, these efforts seldom considered gaseous
diffusion through soil together with the effects of soil environmental
factors such as soil temperature and soil water content on sink or
source strength....
Gaseous transport through soil in the presence of soil
microorganisms has been investigated. More recently, modeling of
gaseous transport in the unsaturated zone has been investigated.
However, the problem of mathematical model of oxygen and carbon
dioxide transport through soil, as affected by the climatic
conditions, the transport of soil...
Atmospheric boundary layers become stably stratified at night over land when the surface becomes colder than the air layer above. In stable nocturnal boundary layers (SNBL), turbulence becomes weak and intermittent, terrain-induced phenomena such as drainage currents or gravity-waves emerge and the surface heterogeneity is enhanced. Because of their complexity...
Globally intermittent turbulence is characterized by sudden switching from significant turbulence to weak turbulence and back on time scales ranging from seconds to tens of minutes as opposed to microscale intermittency, which is due to organization of small scale gradients by individual eddies on scales as small as the Kolmogorov...
A two-scale approach for the turbulent mixing of momentum in an unstable stratified boundary layer is proposed in an attempt to eliminate existing inconsistencies between parameterized mixing of heat and momentum. The parameterization of the large eddy stress is suitable for simple boundary layer models where computational efficiency is important....
The principles of continuum mechanics provide a consistent
framework for the derivation of mathematical statements describing
transport of water and solute, and growth in plant tissue. These
derivations are based upon the explicit consideration of the tissue as
a mathematical continuum composed of a cell wall matrix, water, and
solute...
Sod-seeding techniques offer graziers a convenient way to introduce superior grass cultivars into underproductive permanent pastures. Production loss and erosion are minimized. In conjunction with improved grazing management and fertilization, renovation can significantly improve yield and quality of pastures. Existent vegetation must be suppressed prior to introducing new cultivars. This...
Sudden changes occur where the mean values associated with two adjacent non-overlapping
windows of data are anomalously different, and the transition between the
window means occurs over a scale that is small relative to the scale of the windows.
Positions of sudden changes can be economically retrieved. The sudden change...
The continuum theory provides a framework in which the growth
of a plant root as a dynamic process involving interactions among
transport of water and solute, cell division, and the subsequent cell
elongation can be described. A plant root is modeled as a one-dimensional,
multi-phase, mathematical continuum. The network of...
The effect of soil water suction and soil temperature on rates
of transpiration, photosynthesis, respiration and nitrogen fixation of
soybean (Glycine max. Merrill, var. Chippewa 64) seedlings was
studied. A special apparatus was developed in which the soil water
suction of several cells with soybeans growing in them could be...
Rates of germination and emergence of corn were measured as
influenced by soil physical parameters using blotter paper and a sandy
loam soil as growth media. The corn seeds used were a hybrid of
Funk's (DJ7xLH93).
Experimental conditions were soil temperature of 20°C, 25°C,
30°C, and 35°C, soil water potential...
In this dissertation, we investigate three numerical methods for inverting the Laplace transform. These methods are all based on the trapezoidal-type approximations to the Bromwich integral. The first method is the direct integration method: It is a straightforward application of the trapezoidal rule to the Bromwich integral, followed by convergence...
Sulfur-coated urea (SCU) is a slow release nitrogen fertilizer
manufactured by the Tennessee Valley Authority. Urea granules are
sprayed with molten sulfur, then holes in the sulfur coating are sealed
with a layer of wax sealant. The sulfur coatings are mixtures of
amorphous and crystalline allotropes of sulfur. Coating thickness...
Temperature and water potential effects on the growth,
transpiration, total nonstructural carbohydrate (TNC) content, and
nutrient uptake of sudangrass (Sorghum vulgare var. piper) were
investigated in laboratory experiments. The effect of nitrogen supply
on the growth and nutrient uptake at constant soil water potential was
also investigated in this study....
Laboratory experiments were used to investigate the mechanism
of plant response to water stress by determining the sensitivity of leaf
elongation, photosynthesis and transpiration in young corn plants to a
decrease in leaf water potential.
In initial experiments, 9 day old corn plants were grown at soil
water potentials of...
The influence of soil moisture stress and soil temperature on
transpiration has never been determined explicitly. This relationship
has been neglected mainly because of the lack of a satisfactory method
to control soil moisture stress.
A technique was developed to evaluate this relationship by
controlling soil moisture stress with osmotic...
The statistics describing variations of turbulent motions within the so called inertial range of length scales depend on the scale over which the motions are varying and the "average" rate at which the turbulent kinetic energy is being dissipated on the molecular scale. This hypothesis stemmed from the similarity arguments...
The effect of soil temperature and plant water stress on nitrogen
uptake, growth rate and transpiration rate of wheat (Triticum aestivum
VILL. , Host) seedlings was studied. A special apparatus for the control
of plant water stress and root temperature was used.
Leaf area was measured by the air flow...
Experimental Drainfields: Standard subsurface sewage disposal systems, gravity loaded and 60 cm deep on slopes above 15% did not show signs of effluent surfacing after 14 months of operation. However, subsurface signs of failure were found on both the experimental sites and on older drainfields established in identical soils. Evidence...
There is considerable evidence that the growth and elongation of
plant roots increases linearly or almost linearly with increasing water
contents or decreasing moisture-tension of soil. If this is true it is
difficult to distinguish the effects of different water contents on absorption
phenomena such as water or ion uptake...
Douglas-fir seedlings were inoculated with different species of
ectomycorrhizae-forming fungi in order to test the concept that
ectomycorrhizae enhance the drought tolerance of seedlings and to
investigate the mechanisms responsible for this effect.
Seedlings were transplanted at age 6 to 8 weeks into pots
containing pasteurized loam soil and inoculated...
At present the adsorption kinetic of ions by soil particles is considered to be a surface reaction. When the transport of solutes in soils is described using the one-dimensional flow equation, it becomes a serious problem that lateral diffusion of ions from the bulk solution towards the soil surfaces is...
Leaf elongation is a major indicator of plant growth. It is
controlled by complex interactions of many factors including light
intensity, photoperiod, water availability, atmospheric conditions,
and plant water stress. In this study, the response of leaf elongation
to length of photoperiod and to plant water stress as indicated by...
This study seeks to determine the correlation between changes in statewide land use planning policies and the resulting periods of high or low urban growth in the Willamette Valley, Oregon using automated classification methods and freely available satellite imagery. To protect its farms, forests and open spaces, Oregon became the...
The purpose of this study was to develop a valid and reliable
instrument to measure the organizational climate of the community
college as perceived by community college administrators, faculty, and
classified staff.
There were three phases in this study. The first was to develop a
pool of test items based...
No-till pasture renovation can increase the quality and forage yield of underproductive pastures. Decreased erosion, lower costs, and less lost grazing time are advantages of no-till renovation compared to conventional renovation. Unwanted vegetation is first controlled with herbicides to decrease competition for introduced orchardgrass. Two field trials were conducted using...
In a recent survey, it was observed that many woody plant species grown in Pacific Northwest nurseries exhibited disease symptoms typical of a bacterial infection and Pseudomonas syringae was commonly isolated from these tissues. The distribution of the ice nucleation phenotype among P. syringae strains recovered from these infected woody...
This thesis examines how two grass seed industries
respond to changes in the production environment. Two sets
of factors are necessary to understand what adjustments
would be made. First, it is necessary to know the nature of
the markets and whether market power is being exerted.
Second we need to...
This dissertation consists of two articles to be submitted for publication. The first,
a literature review, makes visible common influences on science teaching self-efficacy
beliefs and also points to potentially invisible validation concerns regarding the
instrument used. The second investigates the participants' invisible science teaching self-efficacy
beliefs and, through the...
The purpose of this study was to determine if there were common
factors influencing student decisions to terminate course work at the
College of San Mateo, San Mateo, California.
The following six null hypotheses were tested:
1. There will be no significant difference in responses
among those enrolled in transfer...
Over the past twenty years, the national three-year graduation rate for community college students has ranged from 44% to roughly 31% in 2013 (NCES, 2013). As a way to address such low graduation rates, colleges have implemented a myriad of services and programs (i.e., tutoring, mentoring, etc.). Another intervention is...
Interpretive rangers serve as one of the major educational resources that visitors may encounter during their visit to a park or other natural area, yet our understanding of their professional growth remains limited. This study helps address this issue by developing an instrument that evaluates the beliefs of resource interpreters...