An experiment was conducted to evaluate the influence of forest fuels reduction on the diet quality, botanical composition, relative preference, and foraging efficiency of beef cattle grazing at different stocking rates. A split plot factorial design was used, with the whole plots (3 ha) being fuel reduced or no treatment...
The results presented in this dissertation address a number of questions regarding late Pleistocene and Holocene ice-sheet and climate interactions, spanning disciplines involving paleoclimatology and atmospheric science. These studies use various techniques in geochemistry, climate modeling, and ice-sheet modeling to address ice- sheet response to climate and the attendant interactions...
This thesis presents the results of an investigation into the interactions between the present-day South Cascade Glacier and the former Mauna Kea ice cap at short (annual to centennial) and long (millennial and multimillennial) time scales. To quantify the response of South Cascade Glacier to atmospheric conditions, a surface energy...
This dissertation explores one overarching question relevant to the
paleoclimate of the latest Pleistocene glacial cycle (approximately the last
130,000 years): “How did spatial and temporal evolution of ocean
temperature, both at the surface and interior, relate to other parts of the
climate system in the late Pleistocene?” Results from...
Due to the increasing cost and concern of catastrophic wildfires in the Western United States, there is an increasing interest in fuels reduction projects. Fuel reduction treatments utilize various methods of thinning and/or prescribed fire to obtain desirable forest stand conditions. However, the effects of fuels reduction on ecosystem function...
An experiment was conducted to evaluate the influence of forest fuels reduction on diet quality, botanical composition, relative preference, and foraging efficiency of beef cattle grazing at different stocking rates. A split plot factorial design was used, with whole plots (3 ha) being fuel reduced or no treatment (control), and...
Management and conservation of rangelands are increasingly concerned with maintaining productivity, species composition, and diversity of native plant communities. We estimated aboveground annual productivity, species composition, and diversity of a native bunchgrass type community across 1152, 0.5 m2 plots at The Nature Conservancy’s Zumwalt Prairie Preserve in northeastern Oregon. Standing...
The goal of dissertation research was to use geochemical, statistical and geological methods to constrain and understand climate variability over several different time scales. Specifically, I have addressed three questions regarding past climate change: (1) how does the record of Irish cirque glaciers constrain the dimensions of the Irish Ice...
This dissertation presents the results of statistical analyses of large climate datasets from two time intervals – the 20th century instrumental record and the proxy record of the last deglaciation – in order to understand the forcings and mechanisms of past climate variability.
A longstanding question in climate dynamics concerns...
The estimation of standing crop is important in the management of rangeland resources. Direct measurements by clipping, drying, and weighing of herbaceous vegetation are time-consuming and labor-intensive. Therefore, non-destructive methods for efficiently and accurately estimating standing crop are needed in rangeland forage management. We assessed a visual obstruction (VO) technique...
Clark volcano of the Kermadec arc, northeast of New Zealand, is a large stratovolcano comprised of two coalescing volcanic cones; an apparently younger, more coherent, twin-peaked edifice to the northwest and a relatively older, more degraded and tectonized cone to the southeast. High-resolution water column surveys show an active hydrothermal...
We review and synthesize the geologic record that
constrains the sources of sea level rise and freshwater discharge
to the global oceans associated with retreat of ice
sheets during the last deglaciation. The Last Glacial Maximum
(~26–19 ka) was terminated by a rapid 5–10 m sea
level rise at 19.0–19.5...
A survey of the Brothers caldera volcano (Kermadec arc) with the autonomous underwater vehicle ABE has revealed new details of the morphology and structure of this submarine frontal arc caldera and the geologic setting of its hydrothermal activity. Brothers volcano has formed between major SW-NE–trending faults within the extensional field...
Assessing impacts of future anthropogenic carbon emissions is currently impeded by uncertainties in our knowledge of equilibrium climate sensitivity to atmospheric carbon dioxide doubling. Previous studies suggest 3 K as best estimate, 2–4.5 K as the 66% probability range, and non-zero probabilities for much higher values, the latter implying a...
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. Shakun,
3
Natalie M. Mahowald,
4
Peter U. 4
Clark,
5
Patrick J. Bartlein,
6
Alan C. Mix,
1
Ocean island basalts (OIB) with extremely radiogenic Pb-isotopic signatures are melts of a mantle component called HIMU (high µ, high ²³⁸U/²⁰⁴Pb). Until now, deeply dredged submarine HIMU glasses have not been available, which has inhibited complete geochemical (in particular, volatile element) characterization of the HIMU mantle. We report major, trace...
Sea-level and ice-sheet databases have driven numerous advances in understanding the Earth system. We describe the challenges and offer best strategies that can be adopted to build self-consistent and standardised databases of geological and geochemical information used to archive palaeo-sea-levels and palaeo-ice-sheets. There are three phases in the development of...
Most of the policy debate surrounding the actions needed to mitigate and adapt to anthropogenic climate change has been framed by observations of the past 150 years as well as climate and sea-level projections for the twenty-first century. The focus on this 250-year window, however, obscures some of the most...
The major purposes of this study were (1) to construct a reliable and
valid scale for measuring writing self-efficacy levels in adult basic education
students, (2) to further test the scale's validity and reliability by administering
it to a second selected group of adult basic education students, and (3) to...
The purpose of this study was to determine if male and female
Counselor-Trainees enrolled in master's degree programs in the
State of Oregon would emit significantly different responses to a
new and professionally developed video-based client simulation.
The sample consisted of ninety-two Counselor-Trainees
enrolled during the 1975-76 academic year in...
Simulations of past climates require altered
boundary conditions to account for known shifts in the Earth
system. For the Last Glacial Maximum (LGM) and subsequent
deglaciation, the existence of large Northern Hemisphere
ice sheets caused profound changes in surface topography
and albedo. While ice-sheet extent is fairly well
known, numerous...
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or-
bit around the Sun caused Northern Hemisphere ice-sheet re-
treat (Clark et al., 2009; Carlson
The purpose of this study was to understand the individual experiences of four adult literacy practitioners, Anne, Bill, Candy, and Emily, in the first cohort of the Oregon Field-Based Cohort Master's Program. This program, which Oregon established in 1993 as one venue of professional development for adult literacy and English...
Previous Paleoclimate Model Intercomparison Project (PMIP) simulations of the Last Glacial Maximum (LGM) Atlantic Meridional Overturning Circulation (AMOC) showed dissimilar results on transports and structure. Here we analyze the most recent PMIP3 models, which show a consistent increase (on average by 41 ± 26%) and deepening (663 ± 550 m)...
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Glacial Maximum (LGM, 26–19 kyr
before present [Clark et al., 2009]). It is an indicator of the transport
This qualitative study was designed to identify factors
that might affect the psychological and educational wellness
of nontraditional students in nontraditional graduate
programs in Education.
Specifically, informants were selected purposefully
from three Oregon State University extended-campus graduate
programs in Education. Student informants were working
professionals with family obligations. Faculty informants...
The purpose of this investigation was to examine the influence of selected historical, fiscal, and organizational factors on enrollment patterns in Oregon Community Colleges during the academic years 1978-79, 1981-82, and 1984-85. Oregon was selected insofar as it is one of the few remaining states which observes the principle of...
We apply GENMOM, a coupled atmosphere–ocean climate model, to simulate eight equilibrium time
slices at 3000-year intervals for the past 21,000 years forced
by changes in Earth–Sun geometry, atmospheric greenhouse
gases (GHGs), continental ice sheets, and sea level. Simulated
global cooling during the Last Glacial Maximum
(LGM) is 3.8°C and...
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continental ice sheets, GHGs (Clark et
al., 2012), and insolation (Fig. 5). The global average mean
annual
Bimetallic catalysis is a promising way to tune the catalytic properties of heterogeneous catalysts. In particular, bimetallic catalysts are extensively used to enhance the selectivity of monometallic catalysts in a variety of contexts, from oxidation catalysis to oxygenate coupling. In this work, we investigate PdxCuy/SiO2 and PdxAgy/SiO2 catalysts in the...
Many jobs in the United States have shifted to requiring education beyond high school credentials. Many potential workers are enrolled in pre-postsecondary education, or basic skills. A small percentage of students transition from basic skills to postsecondary education. Research identifies key institutional practices and supports have shown to increase transitions,...
Oregon Biography Index is intended to serve primarily as a starting point in locating biographies of Oregonians. We have indexed 47 historical volumes which are either entirely devoted to biographies or have large self-contained biographical sections. The profiles in the books vary widely in accuracy and detail. Birth dates of...
National statistics indicate that as many as 23
million adults in the United States are illiterate and
another 40 million lack literacy skills necessary to
function effectively or on more than a narrow basis in this
society. People without literacy skills or who have only
marginal reading ability find themselves...
In recent years interorganizational collaboration has increasingly been emphasized as an important step for addressing inefficiencies in the delivery of human services. Among the many benefits of collaboration described by human service authors are the creation of a more consumer-friendly service system, more efficient use of available resources, and avoiding...
The texture of processed berry fruits changes both during processing
and subsequent storage. A study was made of these changes
in processed strawberries, raspberries, blackberries, and blue-
berries, spin-cooked and stored at 100°F. for 28 days in tin and
glass containers. Four samples, from each of the two replications of...
Climate model simulations and paleoclimate proxies are two tools that enable an understanding of the climate history of the Earth. When utilized together, they form a powerful paradigm for understanding past changes. Proxies are the only physical link to the past conditions on Earth, and models “fill in the gaps”...
Due to lower sea levels during the Last Glacial Maximum (LGM), tidal energy dissipation was shifted from the shallow margins into the deep ocean. Here using a high-resolution tide model, we estimate that global energy fluxes below 200 m depth were almost quadrupled during the LGM. Applying the energy fluxes to...
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was
about 130m lower than it is today [Clark et al., 2009]. The LGM is one of the best studied time
These studies were conducted to examine the
influence of several variables on the growth hormone binding
protein (GHBP) in serum of pigs. Continuous long term
porcine somatotropin (pST) injections (daily for 6-7 wk)
increased GHBP activity (p < .05). However, periodic short
term pST injections (daily, every second d or...
The purpose of this study was to better understand the relationship between selected academic factors and the persistence of GED recipients in community colleges in the state of Oregon. With this purpose in mind, the study addressed the following research question: Is there a relationship between selected academic variables and...
The timing of the last interglacial (LIG) thermal
maximum across the globe remains to be precisely assessed.
Because of difficulties in establishing a common temporal
framework between records from different palaeoclimatic
archives retrieved from various places around the globe, it
has not yet been possible to reconstruct spatio-temporal variations
in...
Rhizopus microsporus is a globally ubiquitous opportunistic human and plant pathogen that is known to harbor endosymbiotic bacteria. Differences between populations of clinical and environmental R. microsporus isolates have yet to be assessed on a global scale. Whole-genome sequence data were used to explore fungal biology and to assess potential...
Questions: Are exotic plant species favoured by non-native ungulate herbivores and disadvantaged by native herbivores in forested rangelands? Do the impacts of ungulates on exotic vs native plants depend on forest management activities such as prescribed fire and stand thinning?
Location: Northeastern Oregon, USA.
Methods: We recorded changes in richness...
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et al. Effects of grazing on plant forest guilds
Acknowledgements
We thank AbeClark, John Cook
The purpose of this study was to compare two groups of freshmen
entering Oregon State University in the fall of 1970; (1) men and
women who were uncertain about choices of academic majors at the time
of entry, and (2) men and women who were certain about choices of
academic...
During the Last Glacial Maximum (LGM, ∼ 21 ky before present) the atmospheric CO2 concentration was about 100 ppm lower than its pre-industrial (PI)value. The missing carbon from the atmosphere must have been stored in thedeep ocean during this period, but the mechanisms driving such re-distribution ofthe carbon cycle are...
This thesis analyzes the efficacy of emancipatory (critical) pedagogical practices in an educational climate of standards-based reform. Using two films noir of the blacklist era--Body and Soul and Crossfire--as the core texts of a unit in a secondary school curriculum, I argue that an emphasis on student agency and a...
Naturally durable woods have a variety of commercial uses. Natural resistance to decay has been evaluated in field and laboratory tests of wood from many species, but there are few places where commercial wood users can find comparative assessments of natural durability. In this report, previous studies have been used...
Ungulates exert a strong influence on the composition and diversity of vegetation communities. However, little is known about how ungulate browsing pressure interacts with episodic disturbances such as fire and stand thinning. We assessed shrub responses to variable browsing pressure by cattle and elk in fuels treated (mechanical removal of...