The recovery of a 1.5 million yr long ice core from Antarctica represents a keystone of our understanding of Quaternary climate, the progression of glaciation over this time period and the role of greenhouse gas cycles in this progression. Here we tackle the question of where such ice may still...
Hatchability of the fertilized avian egg is impacted by factors which can be
categorized as being either genetic or environmental in nature. An elevated
incubation temperature, > 100 F reduces development time (time, days to hatch),
but increases embryonic mortality and lowers the numbers of fertile eggs that will
hatch....
The problem of optimization of stochastic dynamic systems with
random coefficients is discussed. Systems with both Wiener processes and uncertain random-process disturbances are dealt with in
this dissertation, and these include certain bilinear stochastic
systems. It is the purpose of this thesis to study the optimal control and, to some...
To face large scale environmental challenges like climate change, the Obama administration has turned to renewable sources of energy to offset the carbon emissions that result from traditional energy sources like coal and natural gas. However, finding suitable locations for large-scale renewable energy developments has proven difficult due to strong...
The growth of linear disturbances to stable and unstable time-periodic basic states is analyzed in an asymptotic
model of weakly nonlinear, baroclinic wave–mean interaction. In this model, an ordinary differential equation
for the wave amplitude is coupled to a partial differential equation for the zonal-flow correction. Floquet vectors,
the eigenmodes...
Currently, little work has been performed studying energy consumption in hop kilning. This thesis explores drying with an alternative drying schedule that extends the initially elevated drying temperature currently used by growers and examines its impact on drying time and energy use. Extending the time of the initially elevated drying...
The Surface Ocean CO2 Atlas (SOCAT), an activity of the international marine carbon research community, provides access to synthesis and gridded fCO2 (fugacity of carbon dioxide) products for the surface oceans. Version 2 of SOCAT is an update of the previous release (version 1) with more data (increased from 6.3...
We describe an integrated spatially distributed hydrologic
and glacier dynamic model, and use it to investigate
the effect of glacier recession on streamflow variations
for the upper Bow River basin, a tributary of the South
Saskatchewan River, Alberta, Canada. Several recent studies
have suggested that observed decreases in summer flows...
The second law of thermodynamics, through the exergy
concept, allows us to quantify and rationally cost the
consumption of exergy (irreversibility) used to drive the
heat exchange process and the effluent losses of exergy in
a heat exchanger For systems with a network of heat
exchangers, the exergy concept recognizes...
The purpose of this study was to determine the effects of long-term weighted vest
exercise on hip bone mass, functional ability and static balance in elderly women. This was
a within subject exercise intervention study and included a 6-month control period.
Twenty-three subjects (age 85 ± 6) were recruited and...
Methane is a product of biogeochemical processes which respond to changes in climate. The history of atmospheric methane is recorded by ice cores providing insight into past changes in these biogeochemical processes. This dissertation is comprised of three studies which focus on centennial- and millenial-scale variability of methane from ice...
Two experiments were conducted to determine the
effects of riboflavin and pantothenic acid deficiency
on the production of clubbed down embryos in Single
Combed White Leghorn (SCWL) and Rhode Island Red (RIR)
hens.
In experiment 1, sixteen SCWL and eight RIR hens
were assigned to one of four diets calculated...
Simulations of combustion and reacting flows often encounter stiffness in the equations governing chemical kinetics. Explicit solvers for these ordinary differential equations offer low computational expense, but typically cannot efficiently handle stiff systems. In contrast, implicit methods demand greater expense but offer unconditional stability—as a result, most reactive-flow solvers rely...
Combustion emissions produced from burning real transportation fuels have many environmental impacts. However, detailed chemistry across multiple phases, time scales, and thermodynamic conditions make predicting combustion emissions challenging. Detailed modeling of the gas phase alone is prohibitively expensive, due to the large size and stiffness of the kinetic models. The...
The South Pole ice core (SPC14), drilled in the field seasons of 2014/2015 and 2015/2016, is an intermediate length, 1,751-m ice core which preserves a 54,000-year record of past climate and atmospheric composition. The SPC14 ice core adds to the spatial grid of ice cores in Antarctica extending into the...
Three varieties of sweet corn (Zea mays L.) , including
two supersweet (Crisp 'N Sweet 710 and Rogers 3376) and one
normal sweet (Jubilee), were harvested at six stages of
maturity (80-72% moisture for supersweet and 75-68% moisture
for normal sweet) at three days intervals. Changes in
physical and chemical...
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...
Museums, aquariums, and technology centers are informal learning environments that facilitate the understanding of scientific phenomena while supporting self-motivated learning. Families are a social group that frequently visits these sites. There are multiple opportunities for adults and children to engage in independent sense-making and collective discussion about their experiences with...
Outreach is a small, but significant component to modern research.
Developing an exhibit for public display can be an effective way to communicate science to broad audiences, although it may be a less familiar method to scientists than writing papers or giving presentations. I outline the process of developing an...
We investigate the stability of marine ice sheets by coupling a gravitationally self-consistent sea level model valid for a self-gravitating, viscoelastically deforming Earth to a 1-D marine ice sheet-shelf model. The evolution of the coupled model is explored for a suite of simulations in which we vary the bed slope...
Accurately predicting key combustion phenomena in reactive-flow simulations, e.g., lean blow-out, extinction/ignition limits and pollutant formation, necessitates the use of detailed chemical kinetics. The large size and high levels of numerical stiffness typically present in chemical kinetic models relevant to transportation/power-generation applications make the efficient evaluation/factorization of the chemical kinetic...
Background:
Eastern equine encephalitis (EEE) virus (Togaviridae, Alphavirus) is a highly pathogenic mosquito-borne zoonosis that is responsible for occasional outbreaks of severe disease in humans and equines, resulting in high mortality and neurological impairment in most survivors. In the past, human disease outbreaks in the northeastern U.S. have occurred intermittently...
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nesting season]; T, transient.
Vertebrate Host Scientific Name R. C.*
May
No. (%)
June
No
As carbon emissions are negatively impacting ecosystems across the globe, researchers are in a race against time to provide cleaner and more eÿcient power. Detonation engines can help meet the increasing demands for cleaner and more eÿcient power generation by providing an alternative means to use oxy-fuel combustion for carbon...
Integrase catalyzes insertion of a retroviral genome into the host chromosome. Following reverse transcription, integrase binds specifically to the ends of the duplex retroviral DNA, endonucleolytically cleaves two nucleotides from each 3'-end (the processing activity), and inserts these ends into the host DNA (the joining activity) in a concerted manner....
A simple heat exchanger network has been studied as
an example of a dynamically interactive process. The
process is relatively simple, requiring only temperature
measurements and flow rate manipulations. Equations are
presented for the design of a physical process having a
specified steady-state Relative Gain Array and specified
dynamic characteristics....
The chemical kinetics ODEs arising from operator-split reactive-flow simulations were solved on GPUs using explicit integration algorithms. Nonstiff chemical kinetics of a hydrogen oxidation mechanism (9 species and 38 irreversible reactions) were computed using the explicit fifth-order Runge–Kutta–Cash–Karp method, and the GPU-accelerated version performed faster than single- and six-core CPU...
This dissertation concentrates on the controlling factors on the instability of the Laurentide Ice Sheet (LIS) and their effects on abrupt climate change. Northern Hemisphere climate fluctuated abruptly during the last deglaciation possibly related to variability in Atlantic meridional overturning circulation (AMOC) and reduced aerial extent of the LIS. Reductions...
This study addressed the following question: "How does facilitating informal explorations with friends and family outside of a science course help students who are enrolled in the course?" The context was a physics course for prospective elementary and middle school teachers. This was a qualitative study that analyzed student responses...
An important constraint on mechanisms of past
carbon cycle variability is provided by the stable isotopic
composition of carbon in atmospheric carbon dioxide (δ¹³C-CO₂) trapped in polar ice cores, but obtaining very precise
measurements has proven to be a significant analytical challenge.
Here we describe a new technique to determine...
A new and improved stabilizer was developed for the variable speed generation (VSG) system. The VSG system exhibits periodic oscillations which sometimes leads to a loss of synchronism. After careful study, a simple but effective strategy to stabilize the system was implemented with real time digital feedback control. The VSG...
Mercury and arsenic are known developmental toxicants and environmental exposures are ubiquitous worldwide from natural and anthropogenic sources. Prenatal exposure to both contaminants are independently associated with adverse perinatal health outcomes and latent disease risk that could be in part mediated by epigenetic reprogramming events. Fetal programming events involving DNA...
In this work we consider the dependence of solutions to a partial differential equations system on its data. The problem of interest is a coupled model of nonlinear flow and transport in porous media, with applications, e.g. to environmental modeling. The model of flow we consider is known as the...
The HIV pandemic continues to impose enormous morbidity, mortality and economic burdens across the globe. Simultaneously, innovations in antiretroviral therapy, diagnostic approaches and vaccine development are providing novel tools for treatment-as-prevention and prophylaxis. We developed a mathematical model to evaluate the added benefit of an HIV vaccine in the context...
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number of people
susceptible), vaccinated against HIV (R), acute HIV infection (A), undiagnosed HIV
In transboundary river basins, political borders oftentimes trace shared rivers across a basin. A border between territories can be seen as a space that is separated; however, it is actually one with the potential to unite populations and environments. A river basin is generally defined by its topography and hydrology....
The overall goal of this study was to utilize apple pomace, the byproduct from juice processing, as a renewable source of fiber to create sustainable packaging using molded pulp technology. The goal was accomplished through two studies: 1) to modify apple pomace fibers for increasing relative cellulose composition and improving...
Apart from the traditional role of preventing progression from HIV to AIDS, antiretroviral drug therapy (ART) has an additional benefit of substantially reducing infectiousness, making them potentially an important strategy in the fight against HIV. Recent advances in drug therapy have also seen the use of antiretroviral drugs as a...
Hydrological and biogeochemical processes occurring throughout a watershed are typically reflected in stream water chemistry, including in coastal watersheds. While Oregon Coast Range streams have been studied in the past, there is a dearth of knowledge in terms of seasonal temporal trends and spatial variability that this study seeks to...
Deoxyribonucleoside triphosphate (dNTP) concentrations measured in cells are not symmetric. dGTP almost always represents only 5-10% of the total dNTP pools in cells. In an in vitro replication system involving semiconservative replication from an SV 40 origin, the mutation frequency of an M13 phagemid replicated by human cell extracts in...
Studies on net carbon exchange, ¹⁴
C assimilation, and growth
analysis were done on four cultivars of high yielding soft white
winter wheat (Triticum aestivum L. em Thell), Anza/Sturdy, Hill-
81, Stephens, and Yamhill, which differ in morphology, maturity,
and yield, to see if differences in production and distribution
of...
Quantifying the mass transport through marine sediments, and the geochemical response to such flow with numerical models has become a common and powerful approach for geochemical data interpretation. In this dissertation, I developed and applied transport-reaction models to unravel complex and interdependent reactions involving carbon, sulfur and silica transformations in...
The primary purpose of this study was to (1) develop methods for the analysis of and (2) provide information on the chemical nature of reducing ends in typical cellulose substrates used for the study of cellulolytic enzymes. The studies were designed such that values obtained for cellulose substrates were compared...
The rare earth elements (REEs) have been established as powerful tracers for a range of physiochemical processes occurring in the natural environment. They also hold significant economic importance as many technological advancements are reliant upon the REEs for their unique magnetic, luminescent, and electrochemical characteristics. In sedimentary settings, understanding the...