Over the course of the last century, a successful history of fire suppression has contributed to unsuccessful present day control over wildfire. In the absence of fire and the janitorial and ecological services it provides, drier inland forests are shifting in species composition and exceeding densities that cannot survive and...
Giant chinquapin (Chrysolepis chrysophylla) is an evergreen hardwood often found as a shrubby understory component of coniferous forests in the Pacific Northwest United States. Due to its ability to sprout quickly after disturbances such as fire and logging it is often viewed as a pest by forest managers. Like its...
Fuel accumulation and climate shifts are predicted to increase the frequency of high-severity fires in ponderosa pine (Pinus ponderosa Dougl. ex Laws) forests of central Oregon. The combustion of fuels containing large downed wood can result in intense soil heating, alteration of soil properties, and mortality of microbes. Previous studies...
Background information is presented that provides historical perspectives on the field of mycology in the Pacific Northwest and its role in forest management. The series of events and decisions that have led to previous studies (or lack of studies) in the field also dictate the directions of current research. Culture,...
Ectomycorrhizal fungi (EmF) form symbioses with trees. These symbioses profoundly influence forest ecology. Certain EmF form specialized profusions of hyphae, known as ectomycorrhizal fungal mats (mats) which are visible to the naked eye, alter forest soil biogeochemistry, substantially contribute to soil microbial biomass/respiration and support unique microbial communities. Piloderma and...
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David D. Myrold JaneE. Smith
Ectomycorrhizal fungi (EmF) form symbioses with
Fire suppression in the last several decades has resulted in unprecedented accumulations of organic matter on the landscape, leading to an increase in large, intense wildfires. This study investigated the soil microbial community (using phospholipid fatty acid analysis) across recently burned forests on the eastern slope of the Cascade Range...
Land managers, scientists, and the interested public are confronted with uncertainty about the impacts of salvage logging on soil productivity. In recent years, stand-replacing wildfires in the western United States have increased in frequency, prompting the need to evaluate the effect of post-fire treatments on forest ecosystem recovery. This study...
Chemical compounds produced by organisms, or natural products, are excellent sources of inspiration for anticancer pharmaceutical discovery (Rodrigues et al., 2016). Microtubule targeting agents are a specific class of compounds, often discovered from natural sources, that have been developed as clinically successful anticancer therapies (Steinmetz and Prota, 2018). In the...
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JaneE. Ishmael, Ph.D.
Chemical compounds produced by organisms, or natural products, are
Cancer is the second leading cause of death in the United States. To date, over 60% of current anticancer drugs were inspired by the discovery of chemical structure from nature, commonly known as a natural product. This work represents the biological characterization of several marine natural product compounds and their...
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JaneE. Ishmael
Cancer is the second leading cause of death in the United States. To date
Natural products from both terrestrial and marine sources represent a significant source of novel drug leads, and have previously been developed into clinically-approved agents for the treatment of various human diseases. This work represents the biological characterization of the mechanistic basis for activity of several natural product structures in models...
Autophagy, a homeostatic degradation pathway, has a role in promoting cell survival under stress conditions, but can also promote cell death under conditions of sustained stress. This project investigates the cytotoxic potential of coibamide A and other natural products in autophagy-deficient and wild-type mouse embryonic fibroblasts (MEFs). Wild-type MEFs were...
Coibamide A is a methyl-stabilized cyclic depsipeptide with a lariat side chain that was isolated from a marine cyanobacterium as part of an International Cooperative Biodiversity Groups program based in Panama. Previous testing of this potent and selective growth-inhibitory agent in the National Cancer Institute (NCI) in vitro 60 human...
EF-hand proteins are a conserved family of proteins that are modulated by divalent cations and regulate diverse cellular activities. In the present study we characterized the molecular determinants of myosin regulatory light chain (RLC) interaction with several subunits of the N-methyl-D-aspartate (NMDA)-type glutamate receptor. Myosin RLC is an EF-hand protein...
The study of nonlinear vibrations of systems having two
degrees of freedom has met considerable attention during the past
few years. Nonlinear symmetrical systems have received most of it.
Normal mode motion of a system is defined as a periodic motion
such that the masses of the system assume repeated...
A mechanism is a constrained kinematic chain composed of
gears, links, cams, or the like. Mechanisms are the building blocks
of all machines, and, as such, their evaluation is of considerable
importance to the mechanical designer. Because the mathematical
analyses of systems with four or more moving members has been...
These studies are concerned with the forced motion of a two-degree-of-freedom system consisting of a "flexible beam" supported
by pendulum type hangers.
Using an asymptotic method, an approximate solution to the
nonlinear equations of motion was found. The solution takes the form
of a series in powers of the amplitude...
This thesis deals with the effect of pressure coupling on the
stresses in shells having geometric discontinuities. The problems
are, 1) cylinder with an axially symmetric thickness change and
2) cylinder with a hemispherical end closure. Solutions to the
above problems are based on differential equations that included the
straightening...
A model for analytical study of the attitude stability of an
orbiting satellite consists of a rigid body whose mass center is constrained to move at constant speed in a circular path about the
center of an inverse-square force field. The body is assumed to
have one axis of inertial...
The Timoshenko beam theory, as an engineering alternative to
the elementary and exact theories, introduces a factor, k', called
the shear coefficient which has been given various interpretations and
values. It is the objective of this study to experimentally evaluate
k' for a brass bar of rectangular cross-section.
Analytical results...
The equations which govern the motion of a rigid satellite in
an inverse-square force field exhibit a weak coupling between the
translation of, and the rotation about the center of mass. The effects
of this translational-rotational coupling on the equilibrium positions
in a circular orbit, and their stabilities are examined....
The purpose of this study was to compare the effectiveness of a
learner-centered teaching system and that of a conventional teaching of
basic electricity to university students. For this study 65 students
enrolled in basic electricity at Arizona State University in Tempe,
Arizona were used, distributed in two fall semester...
Purpose of the Study
The purpose of this study was to determine the exposure and
influence of recruitment techniques and influential sources and factors
which influenced student selection of vocational-technical education.
Procedures
The data for this study were obtained through the use of a student
questionnaire. The questionnaire was administered...
The crankshaft of an internal combustion engine
experiences torsional vibrations which become critical at
certain running speeds and can cause overstressing in the
crankshaft, leading to failure in some cases.
The object of this study was to design, construct and
test an instrument to measure these oscillations at one
point...
There were six major objectives of this study. The first was to
identify the common career education competencies that elementary
and/or junior high school teachers should have as they adopt and
utilize the concepts of career education. The second purpose was to
identify where, in the professional preparation of the...
The equations of motion of a suspended, inextensible cable in
the absence of damping are studied. A method is developed and
illustrated for determining the frequencies and mode shapes for small
oscillations about the equilibrium configuration.
With the introduction of a new variable, the fourth order equation
governing tangential displacement...
Purpose of the Study:
The purpose of this study was to identify and compare the current
written philosophical expressions of industrial arts with the
acceptance of these by select groups of industrial arts teacher educators.
Procedure:
The data for this study were obtained through the use of a
questionnaire derived...
The Purpose of the Study
The central purpose of this study was to identify the common
competency elements deemed necessary for entry-level vocational
certification and to develop these elements into groups that would
serve as a basis for use in an occupational competency test. Questions
to be answered from the...
The equations of motion of an elastic cable suspended in a
viscous medium from two arbitrary points are derived. These are
then linearized for the undamped, inextensible case, and it is found
that the equations describing the in-plane motion of the cable are
then independent of the equation describing the...
The stability of small oscillations of the troposkeinshaped
blade used on Darrieus wind turbines is investigated.
The blade is assumed to be attached to a perfectly rigid rotor
shaft and spinning in still air. Linear equations of motion are
derived which include the effects of in-plane, out-of-plane,
and torsional stiffness,...
A need exists to develop a high speed dynamic tow carriage used to
motivate hydrodynamic specimens through a fluid environment. It is
desired to simulate high Reynolds number unsteady flow about the
specimen by towing the specimen through the fluid. The fluid
environment is to be provided by the existing...
To design and precisely control a manipulator requires
developing an efficient dynamic model of the system. The
present work demonstrates how this can be accomplished by
employing Kane's dynamical equations. First, a detailed
manual derivation of the equations of motion for a
particular robot is presented in such way that...
For control of a flexible manipulator, the assumed- mode method is applied to the mathematical model of the model reference adaptive system. In the assumed-mode method, the flexible, continuous manipulator is described by a limited number of degrees of freedom. A modified model reference adaptive system is studied for direct...
Control of high-speed, light-weight robotic manipulators is a challenge because of their special dynamic characteristics. In this work, a two-stage control algorithm for the position control of flexible manipulators is proposed. First, the more complex, flexible robot system is replaced by a simplified hypothetical rigid body system (HRRA) with off-line...
In this paper, a numerical method is used to predict
the response of an elastic body during a collision in which
both normal and tangential impulses are important. Results
are compared with those from simplified prediction
procedures, which stem from the assumptions that the energy-returning
capacity of the normal deformation...
Even though the elastic deformations that occur during the
impact of colliding bodies may be small in comparison to their actual
dimensions, they play an important role in mechanical collisions.
During the time the bodies are in contact, elastic, friction, and inertia
properties combine to produce a complex variation of...
Impact is a large and complex field. It embraces both structures as simple as a
nail, and more complex systems, such as a car collision. A central feature of impact
theory is finding the dependence between the velocities before and after impact. The
transformation law of the velocities in an...
Predictions of mechanical collisions between two bodies frequently cannot be completed by the impulse-momentum equation together with a complete description of the motion of the system at the initial contact. Additional account must be taken of the deformations and frictional interaction induced by the impulsive reaction force, where the bodies...
The purpose of the study was to identify a list of skills, knowledges and related factors that are common to fourteen occupational cluster areas representative of the work community of Oregon. PROCEDURES A list of skills, knowledges and related factors needed for successful employment was derived from existing task analyses...
This thesis presents a method for determining the
kinematic geometry of arthropod legs. A kinematic
description makes possible the analysis of arthropod leg
motion, as a prelude to investigating how various arthropod
species are able to negotiate diverse terrains. Such
knowledge will aid in design of legged vehicles.
The focus...