Oxygen uptakes of Douglas-fir beetles collected during November
1969 through April 1970 were measured at different experimental temperatures.
The oxygen uptakes of adult beetles increased at each
experimental temperature as the seasons progressed from winter to
spring.
The larval and pupal Douglas-fir beetles, collected in February
1970, had lower oxygen...
Microtus canicaudus Miller, the gray-tailed vole, was studied
in the field and laboratory in order to clarify aspects of the relationship
of this species to its habitat. All trapping and sampling was done
on permanent pasture land in the William L. Finley National Wildlife
Refuge 12 miles south of Corvallis,...
A method was developed for converting the food producing capabilities
of Oregon's soils to numerical data from which state and county
carrying capacities for human populations could be calculated. Another
method was developed for converting the needs for housing and related
support construction to numerical data which would consume cultivated...
A conceptual model of the tidal flat system, emphasizing the
sulfur cycle was presented. Measurements were made of the vertical
distribution within tidal flat deposits of total aerobic and sulfate
reducing bacteria, total sulfides, redox potential, volatile solids,
and particle size. Variations in dissolved oxygen and free sulfides
in the...
Thais emarginata is a gastropod which inhabits the midlittoral
zone of the intertidal region. Oxygen consumption of high-level and
low-level organisms was determined at various seasons of the year
over an experimental temperature range of 5 to 20° C.
No significant difference in respiratory rate between separate
populations of high-level...
Abbott Creek Natural Area is a 2600 acre research area of the
Mixed-Conifer forest type. This study delineated plant association
units within the area, and demonstrates the use of the computer program
SIMORD as a tool in the definition of such associations. One
hundred fourteen sites were sampled by a...
In this work, we systematically explore the effectiveness of optical aberration correction over a wide range of optical depths using the Segmented and Zernike Polynomial bases. We manufacture a set of 16 optical phantom samples consisting of a clear polyester resin substrate embedded with varying concentrations of aluminum oxide (Al₂O₃)...
Hop powdery mildew (Podosphaera macularis) was confirmed in the Pacific Northwest in 1996. Before 2012, the most common race of P. macularis was able to infect plants that possessed powdery mildew resistance based on the R-genes Rb, R3, and R5. Post 2012, two additional races of P. macularis were discovered...
Using a plastic bottle, we explore the capabilities of a reflective phase-only Spatial Light Modulator (SLM) in removing wavefront aberrations using a Zernike polynomial phase mask, with the modulators phase depth limited to 0.8π radians. Wavefront aberrations, which can be modeled with Zernike polynomials, distort image transmission through various optical...
A multi-year field study was conducted in Oregon and Washington to evaluate the influence of nitrogen fertilization rate and timing on cone quality, nitrate accumulation in cones, severity of powdery mildew (caused by Podosphaera macularis), arthropod pests, and the stability of conservation biological control of the twospotted spider mite (Tetranychus...
Using a spectrometer and photomultiplier tube, I measured the electromagnetic radiation transmittance properties of three types of tissue-- ventral skin, cardiac muscle, and liver tissue--in the red-sided garter snake Thamnophis sirtalis parietalis between the wavelengths of 450 and 850 nanometers (nm). Control readings were taken using a 10⁻² neutral density...
In recent decades, the cell phone has provided a convenient form of long-distance communi-cation to the general public. Despite the technological improvements since, cell phones and their smartphone successors have suffered from a lack of clarity over a typical voice call, a result of their limited bandwidth. New phone services,...
The development and some applications of holographic optical tweezers (HOT) are presented. Our HOT system uses a spatial light modulator (SLM) to control the location and properties of the optical trap. We have developed a method for optimizing the diffraction efficiency of a SLM that can be applied in situ...
A method for determining bandgap energy using diffuse reflection is presented. The method uses bifurcated fiber optic cables to measure the diffuse reflection of diffusely reflective materials. The absorption spectrum is extrapolated from the diffuse reflection spectrum and used to determine the bandgap of powdered materials. The theory of nonspecular...
Podosphaera macularis, causal agent of hop powdery mildew, is known to produce cleistothecia (syn. chasmothecia) in eastern North America and Europe, but ascocarps are not reported from the Pacific Northwestern region of North America. Reasons for the apparent absence of cleistothecia in the Pacific Northwest are unknown. We established that...
:
_____________________________________________________________________
DavidH. Gent
Podosphaera macularis, causal agent of hop powdery mildew, is known to
Doppler-free saturation spectroscopy in an optically thick atomic vapor is used in an
optical-feedback configuration for two semiconductor diode laser systems. One laser
system consists of an unmodifed, commercially available diode laser. The other laser
system consists of a diode laser initially stabilized by optical feedback from a diffraction
grating....
A low velocity, low temperature beam of atoms is produced
from a two-dimensional magneto-optic trap known as an atomic
funnel. The funnel provides simultaneous spatial and velocity
compression of atoms and will provide a source for a three-grating
atomic interferometer. Rubidium atoms from an oven are slowed
by chirped cooling...
We have developed simple and inexpensive laser systems
using grating-feedback diode lasers with electronic feedback to the
injection current. These grating-feedback lasers can be
continuously scanned up to 10 GHz and have a linewidth of 150 kHz.
The three electronic frequency-stabilization systems we developed
use polarization spectroscopy, etalon transmission and...
A continuous, low-velocity, nearly monochromatic atomic beam is created using
laser cooling and two-dimensional magneto-optic trapping. Rubidium atoms from an
effusive oven are slowed and cooled using Zeeman-tuned slowing. The scattering force
from a counter-propagating, frequency-stabilized diode laser beam is used to decelerate
the thermal beam of atoms to a...
The three-grating optical interferometer is studied to identify restrictions
on alignment and improve stability. A description of the way a three-grating
interferometer works is given as well as a method for proper set up. The overall
power loss through the three gratings is measured and can be used to estimate...
In an effort to develop an optical-acoustical understanding of ultrasound contrast agent microbubble dynamics in a micro-environment that resembles blood vessels, this thesis presents experimental work on optical trapping and acoustical probing of ultrasound contrast agent microbubbles confined in regenerated cellulose capillaries. First, we showed by acoustical means that the...
A method for bandgap energy determination using di use re ection is presented and compared to the traditional integrating sphere method. We have found the bandgap energies of ZnO, TiO₂, Cu₂O, Si, SnZrS₃, SnZrSe₃, Sn₂S₃, and BiCuOSe powders with both methods and found they agree within 0.03 eV. We have...
Optical tweezers are capable of trapping micron sized particles through the transfer of
the momentum of light. These capabilities are expanded through the use of computer
controlled holograms for beam shaping. This hologram creation is facilitated through the use of
a spatial light modulator, which is a liquid crystal device...
The LIGO interferometers have reached their designed sensitivity level which is greater than any other interferometer ever built. At this point, it is important to have a proper understanding of small perturbations that might still exist (until now these issues did not come to the forefront because other more critical...
The optical characterization of transparent conductive thin films is demonstrated. The basics of transparency and conductivity, as they relate to transparent conductor research, are explained. A functional model of the reflectance and transmittance of a sample film, including interference fringes, is derived from the Fresnel electric field amplitude coefficients. The...
A method has been developed to measure the thickness of ZnS thin films on Si using optical interference. Thin film optical interference fringes are dependent upon the thickness of the film, and for this reason the thickness can be determined by measuring reflectance spectrum of a thin film. A grating...
Lingcod are an overexploited fish species in the Pacific Northwest and although there has been extensive study of the habitat requirements of adults, particularly during spawning, relatively little is known regarding the habitat requirements of post-settlement juveniles. Many juvenile fish use structural components of habitat to alleviate the risk of...
The two most economically important plant pathogens in the Pseudoperonospora (Peronosporaceae) genus are P. cubensis, causal agent of cucurbit downy mildew, and P. humuli, causal agent of hop downy mildew. These organisms have been shown to be very closely related phylogenetically and morphologically. In 2005, researchers in Korea proposed that...
:
_____________________________________________________________________
David. H. Gent Cynthia M. Ocamb
The two most economically important plant pathogens in
