Physical Sciences and Mathematics Commons^™

A General Elliptic Nonlinear System Of Two Functions With Application, Timothy Robertson, Joon Hyuk Kang

Faculty Publications

The purpose of this paper is to give a sufficient condition for the existence and nonexistence of positive solutions to a rather general type of elliptic system of the Dirichlet problem on the bounded domain Ω in Rn. Also considered are the effects of perturbations on the coexistence state and uniqueness. The techniques used in this paper are upper-lower solutions, eigenvalues of operators, maximum principles and spectrum estimates. The arguments also rely on some detailed properties for the solution of logistic equations. These results yield an algebraically computable criterion for the positive coexistence of competing species of animals in many …

Growth Promotion Of Tomato By The Implementation Of Phosphate Solubilizing Bacteria And Plant Growth Regulators -Producing Bacteria In Calcareous Saline Soil In The United Arab Emirates, Asma Hamad Alsedeeri

Theses

In the present thesis, the ability of different plant growth promoting actinomycetes to promote the growth of tomato plants under saline conditions was examined using phosphorus solubilizing actinomycetes and/or plant growth regulates producing actinomycetes compared to tomato plants grown in soil not amended with any actinomycetes isolates. The overall aim of the present project was to determine whether enhanced phosphorus solubilization, as a result of soil inoculation with either phosphorus-solubilizing actinomycetes and/or with the production of plant growth regulators by plant growth promoting actinomycetes or the combination of both characteristics will results in the promotion of tomato plant growth.

To …

Changing Trends In Wave Heights In The U.S. Mid-Atlantic Region, Hillary Lane

Civil & Environmental Engineering Theses & Dissertations

The pace and effects of climate change are an area of constant focus for coastal engineers as evolving patterns in the atmosphere worldwide affect the oceans and coasts on a regional and global scale. Surface waves respond to changing wind patterns both locally and from propagating swell, and the difficulty in predicting future wind patterns is well-established. Expectations that climate change will result in more frequent and intense coastal storms and consequently greater wave heights in the North Atlantic are still unrealized, and recent forecasts from a variety of atmosphere-ocean coupled global climate models instead predict decreasing wave heights through …

Optimization Of Fuel Consumption For Municipal Solid Waste Collection In Al Ain City, Uae, Elkhalifa Mohamed Zeyada Swar Aldahab

Theses

Collection and transportation of municipal solid waste (MSW) often account for a significant amount of the total budget allocated for waste management. A major portion of that is attributed to fuel consumption. Meanwhile, vehicles involved with waste collection can emit significant levels of atmospheric pollutants. Hence, optimization of waste collection yields both financial and environmental benefits. No work has been done to optimize fuel consumption during MSW collection in Al Ain city. In this study, several cases were developed using ArcGIS Network Analyst tool in order to establish optimum conditions for MSW collection in Um Gafa district in Al Ain …

Multiple Imputation Of Missing Data In Structural Equation Models With Mediators And Moderators Using Gradient Boosted Machine Learning, Robert J. Milletich Ii

Psychology Theses & Dissertations

Mediation and moderated mediation models are two commonly used models for indirect effects analysis. In practice, missing data is a pervasive problem in structural equation modeling with psychological data. Multiple imputation (MI) is one method used to estimate model parameters in the presence of missing data, while accounting for uncertainty due to the missing data. Unfortunately, commonly used MI methods are not equipped to handle categorical variables or nonlinear variables such as interactions. In this study, we introduce a general MI framework that uses the Bayesian bootstrap (BB) method to generate posterior inferences for indirect effects and gradient boosted machine …

The State Of Man-In-The-Middle Tls Proxies: Prevalence And User Attitudes, Mark Thomas Oneill

Theses and Dissertations

We measure the prevalence and uses of Man-in-the-Middle TLS proxies using a Flash tool deployed with a Google AdWords campaign. We generate 15.2 million certificate tests across two large-scale measurement studies and find that 1 in 250 TLS connections are intercepted by proxies. The majority of these proxies appear to be benevolent, however we identify over 3,600 cases where eight malware products are using this technology nefariously. We also find thousands of instances of negligent, duplicitous, and suspicious behavior, some of which degrade security for users without their knowledge. Distinguishing these types of practices is challenging in practice, indicating a …

Peering Through The Cloud—Investigating The Perceptions And Behaviors Of Cloud Storage Users, Justin Chun Wu

Theses and Dissertations

We present the results of a survey and interviews focused on user perceptions and behaviors with respect to cloud storage services. In particular, we study behaviors such as which services are used, what types of data are stored, and how collaboration and sharing are performed. We also investigate user attitudes toward cloud storage on topics such as payment, privacy, security, and robustness. We find that users are drawn to cloud storage because it enables robust, ubiquitous access to their files, as well as enabling sharing and collaborative efforts. However, users' preferred medium for file sharing continues to be email, due …

Climate Change Impacts On Freshwater Wetland Hydrology And Vegetation Cover Cycling Along A Regional Aridity Gradient, Philip A. Fay, Glenn R. Guntenspergen, Jennifer H. Olker, W. Carter Johnson

Natural Resource Management Faculty Publications

Global mean temperature may increase up to 6°C by the end of this century and together with precipitation change may steepen regional aridity gradients. The hydrology, productivity, and ecosystem services from freshwater wetlands depend on their future water balance. We simulated the hydrology and vegetation dynamics of wetland complexes in the North American Prairie Pothole Region with the WETLANDSCAPE model. Simulations for 63 precipitation × temperature combinations spanning 6°C warming and −20% to +20% annual precipitation change at 19 locations along a mid-continental aridity gradient showed that aridity explained up to 99% of the variation in wetland stage and hydroperiod …

The Persistence And Characteristics Of Chinook Salmon Migrations To The Upper Klamath River Prior To Exclusion By Dams, John B. Hamilton, Dennis W. Rondorf, William R. Tinniswood, Ryan J. Leary, Tim Mayer, Charleen Gavette, Lynne A. Casal

Wildland Resources Faculty Publications

In this research article, John Hamilton and his co-authors present extensive new research and information gathered since a 2005 publication on the historical evidence of anadromomous fish distribution in the Upper Klamath River watershed. Using historical accounts from early explorers and ethnographers to early-twentieth-century photographs, newspaper accounts, and government reports, the authors provide a more complete record of past salmon migrations. The updated record “substantiate[s] the historical persistence of salmon, their migration characteristics, and the broad population baseline that will be key to future commercial, recreational, and Tribal fisheries in the Klamath River and beyond.” During a time when salmon …

Trimethylamine N-Oxide And Mortality Risk In Patients With Peripheral Artery Disease, Vichai Senthong, Zeneng Wang, Yiying Fan, Yuping Wu, Stanley L. Hazen, W.H. Wilson Tang

Mathematics and Statistics Faculty Publications

Background: Production of the proatherogenic metabolite, trimethylamine N-oxide (TMAO), from dietary nutrients by intestinal microbiota enhances atherosclerosis development in animal models and is associated with atherosclerotic coronary artery disease in humans. The utility of studying plasma levels of TMAO to risk stratify in patients with peripheral artery disease (PAD) has not been reported. Methods and Results: We examined the relationship between fasting plasma TMAO and all-cause mortality (5-year), stratified by subtypes of PAD and presence of coronary artery disease in 935 patients with PAD who underwent elective angiography for cardiac evaluation at a tertiary care hospital. Median plasma TMAO was …

ความลับจากตะกอนถ้ำ, สกลวรรณ ชาวไชย

Thai Environment

No abstract provided.

Distributions Of Euphausia Superba, Euphausia Crystallorophias, And Pleuragramma Antarcticum With Correlations To Environmental Variables In The Western Ross Sea, Antarctica, Linnea Brynn Davis

OES Theses and Dissertations

Antarctic krill (Euphausia superba), crystal krill (Euphausia crystallorophias), and Antarctic silverfish (Pleuragramma antarcticum) are key mid-trophic level species in the Ross Sea food web that provide connectivity between primary production and the upper trophic levels. Distributions of these species were constructed from net-based and acoustic observations collected in the western Ross Sea from 1988-2004. Distributions of environmental conditions in the Ross Sea were obtained from a high-resolution circulation model (temperature, mixed layer depth, surface speed) and satellite-derived observations (chlorophyll, sea ice cover). These distributions were analyzed with a range of statistical methods to determine …

Application Of The Dispersive Optical Model To 208pb, Michael Keim

Undergraduate Research Symposium Posters

A review of developments for the application of the dispersive optical model (DOM) to ²⁰⁸Pb is presented. By providing appropriate parameters describing real and imaginary parts of a nonlocal self-energy, connected through a dispersion relation, reasonable reproductions of both scattering and bound-state properties are generated. By fitting these parameters to experimental data, a more accurate description of the neutron skin may be achieved, which would have implications for the physics of neutron stars.

Responding To The U.S. Research Community's Liquid Helium Crisis, Simon R. Bare, Michael Lilly, Janie Chermak, Rod Eggert, William Halperin, Scott Hannahs, Sophia Hayes, Michael Hendrich, Alan Hurd, Mike Osofsky, Cathy Tway

Chemistry Faculty Research

An Action Plan to Preserve U.S. Innovation. This report lays out the issues facing researchers who use liquid helium and the negative impact on U.S. innovation. The report then proposes five key steps that will have a transformative effect on the ability to maintain the ready availability of helium and ensure the vibrancy of the U.S. low-temperature research capability. These recommendations focus on: conservation of helium use; a mechanism to pay for the capital investment required for helium recycling; a mechanism to ensure an appropriate price is paid by researchers for helium; and a methodology which allows researchers to best …

Bioenergetics: Experimental Demonstration Of Excess Protons And Related Features, Haitham A. Saeed

Chemistry & Biochemistry Theses & Dissertations

Over the last 50 years, ever since the Nobel-prize work of Peter Mitchell’s Chemiosmotic theory, the question whether bioenergetics energy transduction occurs through localized or delocalized protons has been a controversial issue among scientists. Recently, a proton-electrostatics localization hypothesis was formulated which may provide a new and clear understanding of localized and delocalized proton-coupling energy transduction in many biological systems. The aim of this dissertation was to test this new hypothesis.

To demonstrate the fundamental behavior of localized protons in a pure water-membrane-water system in relation to the newly derived pmf equation, excess protons and excess hydroxyl anions were generated …

Co2 Enhanced Oil Recovery Life Cycle Analysis Model (Rev. 2), Nicholas A. Azzolina, Wesley D. Peck, John A. Hamling, Charles D. Gorecki, Scott C. Ayash, Thomas E. Doll, David V. Nakles, L. Stephen Melzer

EERC Publications, Papers, & Presentations

In “How green is my oil?” by Azzolina et al., the authors presented an integrated life-cycle model for CO₂-EOR where the CO₂ is sourced from a coal-fired power plant. The model was developed entirely in Microsoft Excel^® to improve transparency and provide a useful tool for other practitioners. This model is an updated version of the model from the article. The cells have been unlocked so they can be modified.

Azzolina, N.A., Peck, W.D., Hamling, J.A., Gorecki, C.D., Ayash, S.C., Doll, T.E., Nakles, D.V., and Melzer, L.S., 2016, How green is my oil? a detailed look …

"Automated Debugging Considered Harmful" Considered Harmful: A User Study Revisiting The Usefulness Of Spectra-Based Fault Localization Techniques With Professionals Using Real Bugs From Large Systems, Xin Xia, Lingfeng Bao, David Lo, Shanping Li

Research Collection School Of Computing and Information Systems

Due to the complexity of software systems, bugs are inevitable. Software debugging is tedious and time consuming. To help developers perform this crucial task, a number of spectra-based fault localization techniques have been proposed. In general, spectra-based fault localization helps developers to find the location of a bug given its symptoms (e.g., program failures). A previous study by Parnin and Orso however implies that several assumptions made by existing work on spectra-based fault localization do not hold in practice, which hinders the practical usage of these tools. Moreover, a recent study by Xie et al. claims that spectra-based fault localization …

Anisoplanatic Electromagnetic Image Propagation Through Narrow Or Extended Phase Turbulence Using Altitude-Dependent Structure Parameter, Monish Ranjan Chatterjee, Ali Mohamed

Electrical and Computer Engineering Faculty Publications

The effects of turbulence on anisoplanatic imaging are often modeled through the use of a sequence of phase screens distributed along the optical path. We implement the split-step wave algorithm to examine turbulence-corrupted images.

Renewable Chemicals And Bioproducts: A Potential For Agricultural Diversification And Economic Development, Henry Brockman

Bulletins 4000 -

Renewable chemicals are a new category of novel products: building blocks and ingredients for the production of chemicals produced from renewable feedstock and sustainable advanced manufacturing processes, leaving a smaller environmental footprint than traditional petrochemicals. Biologically based products are mainly non-food products derived from biomass.

Renewable chemicals represent a market opportunity predicted to grow from US$2.8 billion in 2011 to US$98.5 billion by 2020, driven by consumers demanding safer and more environmentally friendly products and the creation of a market advantage by using novel products in the manufacturing process. Renewable chemicals are a sustainable diversification option for rangeland irrigation precincts, …

Modeling Pyrolysis Of Large Coal Particles With Many Species, Jianqing Li

Master's Theses (2009 -)

Coal currently supplies 40% of the world’s electricity needs, and is one of the most important energy sources. As the initial stage of coal combustion, pyrolysis is a thermal decomposition process which converts coal into light gases and tars, which are subsequently consumed in combustion reactions, as well as solid char. Recently there has been interest in using slow pyrolysis as a stand-alone process for the production of chemicals and fuels from large (mm-scale) coal particles. Simulations can be used to efficiently study the impact of pyrolysis conditions on gas, tar and char yields, as well as gas and tar …

Mapped Tent Pitching Schemes For Hyperbolic Systems, Jay Gopalakrishnan, Joachim Schöberl, C. Wintersteiger

Portland Institute for Computational Science Publications

A spacetime domain can be progressively meshed by tent shaped objects. Numerical methods for solving hyperbolic systems using such tent meshes to advance in time have been proposed previously. Such schemes have the ability to advance in time by different amounts at different spatial locations. This paper explores a technique by which standard discretizations, including explicit time stepping, can be used within tent-shaped spacetime domains. The technique transforms the equations within a spacetime tent to a domain where space and time are separable. After detailing techniques based on this mapping, several examples including the acoustic wave equation and the Euler …

The Associations Between Environmental Quality And Mortality In The Contiguous United States, 2000-2005, Yun Jian, Lynne C. Messer, Jyotsna S. Jagai, Kristen M. Rappazzo, Christine L. Gray, Shannon C. Grabich, Danelle T. Lobdell

OHSU-PSU School of Public Health Faculty Publications and Presentations

Background: Assessing cumulative effects of the multiple environmental factors influencing mortality remains a challenging task.

Objectives: This study aimed to examine the associations between cumulative environmental quality and all-cause and leading cause-specific (heart disease, cancer, and stroke) mortality rates.

Methods: We used the overall Environmental Quality Index (EQI) and its five domain indices (air, water, land, built and sociodemographic) to represent environmental exposure. Associations between the EQI and mortality rates (CDC WONDER) for counties in the contiguous United States (n=3109) were investigated using multiple linear regression models, and random intercept, random slope hierarchical models. Urbanicity, climate and their combination were …

Ubiquitous Electronic Medical Record (Emr) For Developing Countries, Nasser Mohammed Alkathiri

Master's Theses (2009 -)

Around the globe, Healthcare Information Technology (HIT) has been evolved either by governments or healthcare providers. The utilization of these technologies has resulted in the improvement of healthcare services all over the world. This evolution has been characterized by availability, reliability, serviceability to patients, and has been enhanced with increased cost and time efficiency. As such, new systems and terms have been established. Electronic Medical Record (EMR), which can also be used interchangeably with Electronic Health Record (EHR) is considered to be the main transformation in healthcare information technologies. EMR has been aimed to reduce and eliminate existing paper based …

Realizing Urban Water Pollution Impact In Melbourne, Australia Through Painting, Gregory Suplinskas

Independent Study Project (ISP) Collection

Throughout the month of November 2016, I undertook a creative environmental art project in Melbourne, Australia. I chose to create a water-soluble oil painting (dimensions 3 ft. x 4 ft.) that represents water pollution problems in the city of Melbourne, particularly in Port Phillip Bay. These problems include toxic stormwater runoff, plastics pollution and plastic nurdles, as well as nutrient buildup and algal overgrowth. The painting includes messages regarding sustainability; sustainable action limits the use of our natural resources so that humans can preserve the environment for future generations rather than degrade it. In the painting, I combine conceptual and …

The Effects Of Sub-Lethal Predation On The Reproductive Output Of Acanthaster Planci (Crown-Of-Thorns Starfish), Emily Mucha

Independent Study Project (ISP) Collection

Wide-scale declines in live coral cover have been observed throughout history. Modern day coral populations face a multitude of environmental disturbances, however one of the most devastating to the reefs in the Indo-Pacific is the crown-of-thorns starfish (Acanthaster planci), which feeds on the tissues of live corals. The rate at which these individuals feed combined with the explosion of populations in times of outbreak have been seen to exert some of the biggest pressures on coral reefs to date. Following recent episodes of crown-of-thorns starfish (COTS) outbreaks, research on the organism has become increasingly prevalent on the scientific …

Fish Diversity And Coral Health Of Tanzania's Reefs: A Comparative Study Between The Ushongo Village Reef And The Fungu Zinga Reef Over Time, Della Turque, Corinne Casper

Independent Study Project (ISP) Collection

The world’s oceans are becoming increasing acidic due to global climate change, posing a threat to marine ecosystems, including coral carbonate systems. Environmental threats are exacerbated by human development stressors as well: growing populations, dependency on marine resources, and unsustainable practices invaluable marine ecosystems at risk. Tanzania’s coral reef system extends for 3580 km2 (Muhando et al. 2008) near the Tanga region, serving over half a million people who are highly dependent on fishing and other marine resources as their livelihoods (Samoilys et. al. 2008). With Tanzania’s population rapidly growing, the unsustainable pressure on coral reefs for sustenance and livelihood …

Solid Waste Management Of Disposable Diaper Sanitation And The Connection To Environmental Awareness For Women In Zanzibar, Micalea Leaska

Independent Study Project (ISP) Collection

This project examined the solid waste management of disposable diapers in three locations, Stone Town, Mangapwani and Vikokotoni, within Zanzibar, Tanzania. Its methods included field observations of the solid waste disposal system in Zanzibar and interviews with women about their rationales for buying and using disposable diapers. For one of the first times, the data collected during this project will further assist to educate women about the benefits of cloth diapers and the negative effects disposable diapers create for Zanzibari families and the environment. This study has observed one of the most growing concerns regarding excess solid waste contributing to …

The Effects Of Sub-Lethal Predation On The Reproductive Output Of Acanthaster Planci (Crown-Of-Thorns Starfish), Emily Mucha

Independent Study Project (ISP) Collection

Wide-scale declines in live coral cover have been observed throughout history. Modern day coral populations face a multitude of environmental disturbances, however one of the most devastating to the reefs in the Indo-Pacific is the crown-of-thorns starfish (Acanthaster planci), which feeds on the tissues of live corals. The rate at which these individuals feed combined with the explosion of populations in times of outbreak have been seen to exert some of the biggest pressures on coral reefs to date. Following recent episodes of crown-of-thorns starfish (COTS) outbreaks, research on the organism has become increasingly prevalent on the scientific …

Multi-Sector Analysis Of The Progress And Challenges Of Soil-Transmitted Helminth Eradication In Rural Udaipur, Jessica Ellis

Independent Study Project (ISP) Collection

India is home to 240 million children currently at risk of Soil-Transmitted Helminthiasis, which is spread via unclean water, soil, and food, and causes acute pain and malnutrition. While acknowledging the research debates over WASH and mass drug administration, this study seeks to identify the systemic multidisciplinary issues affecting STH elimination efforts in rural Udaipur. Twenty-three interviews were conducted in villages, government departments, NGOs, and medical sectors to identify the challenges within each approach to deworming, and their experiences with multi-sectoral collaboration. The most recurring issues across disciplines were need for invested local leadership, increase in health literacy of adults, …

Potential Impacts Of Climate Change On Photochemistry Of Zostera Marina L., Billur Celebi

OES Theses and Dissertations

Seagrasses account for approximately 10% of the ocean’s total carbon storage, although photosynthesis of seagrasses is carbon limited at today’s oceanic pH. Therefore, increasing atmospheric CO₂ concentration, which results in ocean acidification/carbonation, is predicted to have a positive impact on seagrass productivity. Previous studies have confirmed the positive influence of increasing CO₂ on photosynthesis and survival of the temperate eelgrass Zostera marina L., but the acclimation of photoprotective mechanisms in this context has not been characterized. This study aimed to quantify the long-term impacts of ocean acidification on photochemical control mechanisms that promote photosynthesis while simultaneously protecting …