Digital Commons Network^™

3d Interdigitated Electrode Array (Idea) Biosensor For Detection Of Serum Biomarker, Dheeraj Kumar Bhura

Dissertations and Theses

Miniaturization, integration and intelligence are the developing trends for sensor, especially for biosensors. The development of microelectronics technology is a powerful engine to full this objective. It is well known that the microelectronic fabrication process in proven technology for fabrication of integrated circuits. Advances in the field of micro-electronics and micro-mechanical devices combined with medical science have led to the development of numerous analytical devices in monitoring of a wide range of analytes. The unique properties of nanoscale materials offer excellent prospects for interfacing biological recognition events with electronic signal transduction and for designing a new generation of bio-electronic devices …

Information Processing In Two-Dimensional Cellular Automata, Martin Cenek

Dissertations and Theses

Cellular automata (CA) have been widely used as idealized models of spatially-extended dynamical systems and as models of massively parallel distributed computation devices. Despite their wide range of applications and the fact that CA are capable of universal computation (under particular constraints), the full potential of these models is unrealized to-date. This is for two reasons: (1) the absence of a programming paradigm to control these models to solve a given problem and (2) the lack of understanding of how these models compute a given task. This work addresses the notion of computation in two-dimensional cellular automata. Solutions using a …

Riparian Wetland Response To Livestock Exclusion In The Lower Columbia River Basin, Sarah Ann Holmen

Dissertations and Theses

The purpose of this study was to examine the characteristics of riparian plant communities along a succession gradient of livestock exclusion in the Lower Columbia River Basin (LCRB). Livestock exclusion is an example of a passive restoration practice throughout the region. However, few studies have focused on the effects of livestock or livestock exclusion on riparian wetland ecosystems in this area. Two passive restoration sites, 3 and 13 years since livestock exclusion, and a control site with a continued livestock grazing presence were examined. It was hypothesized that native plant species richness would be lower in the excluded wetlands than …

Foreign Language Teaching In U.S. Higher Education Classrooms: An Investigation Of The Relationship Between Teacher Pedagogical Beliefs And Classroom Teaching, Shaojuan Lin

Dissertations and Theses

Previous research indicates that former schooling is an important factor to shape teachers' beliefs about teaching; teachers change the way they teach when their beliefs about foreign language teaching change. However, little research has discovered direct evidence concerning the processes that effect change in teacher beliefs. This study investigated the relationship between teachers' pedagogical paradigms and practices in Chinese language classrooms. Specifically, a qualitative analysis of educated teachers born in China examined how early pedagogical frames were formed, and then transformed in the context of American classrooms. Results of this study indicate that early schooling, language learning, and initial teaching …

Growth And Optical Characterization Of Zinc Oxide Nanowires For Anti-Reflection Coatings For Solar Cells, Martha Coakley

Dissertations and Theses

The optical properties of solar cells greatly affect their efficiencies. Decreasing the broadband and directional reflectance of solar cells increases the solar irradiance transmitted and absorbed by the cell, thereby increasing the production of electron-hole pairs. Traditional optical enhancements such as light trapping and anti-reflection coatings reduce the reflectance of silicon at an optimized wavelength and angle of incidence. They do not perform as well at high angles of incidence or over the broadband solar spectrum. Theoretical studies suggest that layers with a suitable gradient-index of refraction can create both a broadband and directional anti-reflective coating. Through their variations in …

A Computational Model Of Adaptive Sensory Processing In The Electroreception Of Mormyrid Electric Fish, Eran Agmon

Dissertations and Theses

Electroreception is a sensory modality found in some fish, which enables them to sense the environment through the detection of electric fields. Biological experimentation on this ability has built an intricate framework that has identified many of the components involved in electroreception's production, but lack the framework for bringing the details back together into a system-level model of how they operate together. This thesis builds and tests a computational model of the Electrosensory Lateral Line Lobe (ELL) in mormyrid electric fish in an attempt to bring some of electroreception's structural details together to help explain its function. The ELL is …

"An I Don't Give A Damn 'Bout My Bad Reputation": The Effects Of Family Type And Patriarchy In The Home On Female Adolescent Delinquency And Mental Health, Stephanie-Kaye Guenther

Dissertations and Theses

This study examined the connection between household type and delinquency and depressive symptoms for female adolescents. The present study draws its claims from Power-control theory which, at its most abstract level, predicts gender differences in delinquency based on the level of patriarchy in the family and the theoretical works of Sarah Rosenfield, who argues that it is the over control of females that causes them to have higher rates depression than males. This study hoped to build on research that links differences in family type and parental control to sex differences in delinquency by using the Power-control theory to look …

Total Mercury In Stranded Marine Mammals From The Oregon And Southern Washington Coasts, Nathan J. Wintle

Dissertations and Theses

Muscle samples from 105 marine mammals stranded along the Oregon-Washington coasts (2002-2009) were tested for levels of total mercury by Cold Vapor Atomic Fluorescence Spectrometry. The total mercury present is predominantly in the form of highly toxic methylmercury. After normalizing muscle tissue to 75% water weight, due to variance in water content, Steller sea lions (Eumetopias jubatus) and northern elephant seals (Mirounga angustirostris) exhibited the highest mean concentrations of total mercury followed by harbor seals (Phoca vitulina), harbor porpoises (Phocoena phocoena), and California sea lions (Zalophus californianus); 0.34 ± 0.278, …

Measurement And Characterization Of Terahertz Radiation Propagating Through A Parallel Plate Waveguide, Matthew George Wachsmuth

Dissertations and Theses

As the amount of study into the terahertz (THz) region of the electromagnetic spectrum steadily increases, the parallel plate waveguide has emerged as a simple and effective fixture to perform many experiments. The ability to concentrate THz radiation into a small area or volume enables us to analyze smaller samples and perform more repeatable measurements, which is essential for future research. While the fundamental physics of PPW transmission are understood mathematically, the practical knowledge of building such a fixture for the THz domain and taking measurements on it with a real system needs to be built up through experience. In …

Antioxidant Anthocyanidins And Calcium Transport Modulation Of The Ryanodine Receptor Of Skeletal Muscle (Ryr1), Thomas J. Dornan

Dissertations and Theses

Cardiovascular disease (CVD) claims more lives than any other disease in the world. Although numerous biological pathways share the blame, ventricular tachyarrhythmia (VT) is estimated to account for ~25% of all CVD deaths. A complete understanding of the molecular mechanisms underlying VT is unknown but recent studies have linked VT to improper calcium handling in the heart (canine). The principle calcium regulator in the muscle cell is the calcium ion release channel (aka RyR). Numerous endogenous and exogenous compounds can affect the way the RyR regulates calcium. In particular, abnormal levels of oxidants (reactive oxygen species) can oxidize critical thiol …

Impacts Of Rhizosphere Co₂ On Root Phosphoenolpyruvate Carboxylase Activity, Root Respiration Rate And Rhizodeposition In Populus Spp., Dawn Marie Matarese

Dissertations and Theses

Roots live in and have evolved in a high carbon dioxide (CO₂) environment, yet relatively little research has been conducted on the impacts of soil dissolved inorganic carbon (DIC) on root metabolism. In this thesis, I explore the impacts of root-zone DIC on whole plant biomass accumulation, water use efficiency, and above-ground gas exchange. In addition, I explore the impacts of root-zone DIC on root processes: root PEP-Carboxylase activity, root respiration rate and root exudation of Krebs cycle organic acids.

Root-zone DIC did not impact biomass accumulation, leaf gas exchange parameters or water use efficiency under the growth conditions examined. …

The Effect Of Role Models On The Attitudes And Career Choices Of Female Students Enrolled In High School Science, Stephanie Justine Van Raden

Dissertations and Theses

Girls who have high aptitude in math are not entering careers related to science, technology, engineering, and math (STEM fields) at the same rate as boys. As a result, female students may have fewer employment opportunities. This study explores one potential way to reduce the gap between male and female career aspirations and choices. Specifically, it looks at the impact of bringing women with careers in math- and science-related fields into high school classrooms as role models. The study uses surveys to measure pre- and post-visit perceptions of science and scientific work as well as student's short-term interest in math …

Biological Erosion Of Marine Habitats And Structures By Burrowing Crustaceans, Timothy Mathias Davidson

Dissertations and Theses

Marine bioeroders, borers, and burrowers can have drastic effects to marine habitats and facilities. By physically altering the structure of marine habitats, these organisms may elicit ecosystem-level effects that cascade through the community. While borer damage is typically restricted to a few substratum types, burrowing isopods in the genus Sphaeroma attack a diversity of substrata in tropical and temperate systems. My dissertation examined how boring sphaeromatid isopods affect coastal habitats (saltmarshes, mangroves) and other estuarine substrata as well as marine structures. I used a combination of lab and mensurative field experiments to quantify the effects of boring by isopods and …

Prestructuring Multilayer Perceptrons Based On Information-Theoretic Modeling Of A Partido-Alto-Based Grammar For Afro-Brazilian Music: Enhanced Generalization And Principles Of Parsimony, Including An Investigation Of Statistical Paradigms, Mehmet Vurkaç

Dissertations and Theses

The present study shows that prestructuring based on domain knowledge leads to statistically significant generalization-performance improvement in artificial neural networks (NNs) of the multilayer perceptron (MLP) type, specifically in the case of a noisy real-world problem with numerous interacting variables.

The prestructuring of MLPs based on knowledge of the structure of a problem domain has previously been shown to improve generalization performance. However, the problem domains for those demonstrations suffered from significant shortcomings: 1) They were purely logical problems, and 2) they contained small numbers of variables in comparison to most data-mining applications today. Two implications of the former were …

Molecular Genetic Analysis Of Creld1 In Patients With Heterotaxy Disorder, Samaneh Zhian

Dissertations and Theses

Heterotaxy refers to the abnormal arrangement of internal organs in relation to each other. Model organism studies have shown that functions of more than eighty genes are required for normal asymmetric left-right organ development. CRELD1 has been shown to be necessary for proper heart development and mutations in CRELD1 are known to increase risk of cardiac atrioventricular septal defects (AVSD). AVSD is the most common form of heart defect associated with heterotaxy, and we have previously shown that some individuals heterotaxy-related AVSD have mutations in CRELD1.

Therefore, we propose to examine the CRELD1 gene in a large sample of …

Chronology And Ecology Of Late Pleistocene Megafauna In The Northern Willamette Valley, Oregon, Daniel Mcgowan Gilmour

Dissertations and Theses

This study is an investigation of the timing of extinction of late Pleistocene, large bodied mammalian herbivores (megafauna) and of the environment in which they lived. The demise of the megafauna near the end of the Pleistocene remains unexplained. Owing to potential human involvement in the extinctions, archaeologists have been particularly concerned to understand the causes for faunal losses. Our current lack of understanding of the timing and the causes of the extinctions in North America may result from a deficiency in understanding the histories of each individual species of extinct animal on a local level. Detailed regional chronologies of …

Physical And Electrical Characterization Of Triethanolamine Based Sensors For No₂ Detection And The Influence Of Humidity On Sensing Response, Zachariah Marcus Peterson

Dissertations and Theses

Triethanolamine (TEA) is a semiconducting polymer which exhibits a resistance change when exposed to various gases. The polymer also exhibits a number of reactions with nitrogen dioxide, with the reaction products being heavily dependent on the presence or absence of water vapor. Previous studies have attempted the incorporation of a TEA-carbon nanoparticle composite as the active sensing layer in a chemresistive sensor for detection of NO₂. The incorporation of carbon nanoparticles in the polymer nanocomposite was thought to amplify the sensor's response. There are a number of chemical reactions that can occur between TEA and NO₂, with the reaction products …

Improving Hypothesis Testing Skills: Evaluating A General Purpose Classroom Exercise With Biology Students In Grade 9., Michael Gregg Wilder

Dissertations and Theses

There is an increased emphasis on inquiry in national and Oregon state high school science standards. As hypothesis testing is a key component of these new standards, instructors need effective strategies to improve students' hypothesis testing skills. Recent research suggests that classroom exercises may prove useful. A general purpose classroom activity called the thought experiment is proposed. The effectiveness of 7 hours of instruction using this exercise was measured in an introductory biology course, using a quasi-experimental contrast group design. An instrument for measuring hypothesis testing skill is also proposed. Treatment (n=18) and control (n=10) sections drawn from preexisting high …

Using Archaeological Fish Remains To Determine The Native Status Of Anadromous Salmonids In The Upper Klamath Basin (Oregon, Usa) Through Mtdna And Geochemical Analysis, Alexander E. Stevenson

Dissertations and Theses

Within the Upper Klamath Basin, Oregon, the native status of anadromous salmonids (Oncorhynchus spp.) has been a long standing question. Ongoing efforts to establish if these fish were native to the region prior to the construction of the Copco I Dam on the Klamath River (c.1917) have relied on sparse, contradictory and sometimes unreliable historic documentation and informant testimony. Current restoration projects with very high financial and social costs necessitate accurate and reliable data on salmonid species which once called the region home. Often, archaeolofaunal remains present a novel way to determine species present in an area prior to …

Cultivating Environmental Stewardship In Middle School Students, Kelly Anne Fischer

Dissertations and Theses

Environmental stewardship is an important attribute for students and populations of all ages to have. This study looked at the effect of middle school students of a teacher who participated in a summer field ecology training program taking part in a long-term ecology project, and the impact of the experience on their environmental stewardship attitude. A variety of qualitative and quantitative techniques were used to look at changes in students' environmental stewardship attitudes including: surveying in a pre/post format, teacher, parent, and student focus groups, and teacher interviews. The teacher's experience with the summer field ecology training provided a foundation …

Population Structure Of Island-Associated Pantropical Spotted Dolphins (Stenella Attenuata) In Hawaiian Waters, Sarah Shelby Courbis

Dissertations and Theses

Understanding gene flow, diversity, and dispersal patterns is important for predicting effects of natural events and anthropogenic activities on dolphin populations. With the very recent exceptions of false killer whales (Pseudorca crassidens), spinner dolphins (Stenella longirostris), and common bottlenose dolphins (Tursiops truncatus), Hawaiian odontocete species are managed as single stocks within the U.S. Hawaiian Exclusive Economic Zone. These exceptions are a result of recent studies that have indicated that some species have populations that show fidelity to individual islands or groups of islands, resulting in genetic differentiation, often with management implications. The first part …

Synthesis And Characterization Of Glyconanomaterials, And Their Applications In Studying Carbohydrate-Lectin Interactions, Xin Wang

Dissertations and Theses

This dissertation focuses on the synthesis and characterization of glyconanomaterials, as well as their applications in studying carbohydrate-protein interactions. A new and versatile method for coupling underivatized carbohydrates to nanomaterials including gold and silica nanoparticles was developed via the photochemically induced coupling reaction of perfluorophenylazide (PFPA). A wide range of carbohydrates including mono-, oligo- and poly-saccharides were conjugated to the nanoparticles with high yields and efficiency. New analytical methods were developed to determine the binding affinities of glyconanoparticles (GNPs) with lectins; these include fluorescence-based competition assay, dynamic light scattering (DLS) and isothermal titration calorimetry (ITC). Results showed that the multivalent …

A Self-Configurable Architecture On An Irregular Reconfigurable Fabric, Avinash Amarnath

Dissertations and Theses

Reconfigurable computing architectures combine the flexibility of software with the performance of custom hardware. Such architectures are of particular interest at the nanoscale level. We argue that a bottom-up self-assembled fabric of nodes will be easier and cheaper to manufacture, however, one has to make compromises with regards to the device regularity, homogeneity, and reliability. The goal of this thesis is to evaluate the performance and cost of a self-configurable computing architecture composed of simple reconfigurable nodes for unstructured and unknown fabrics. We built a software and hardware framework for this purpose. The framework enables creating an irregular network of …

Identifying Regional Centers In Washington County, Oregon, Kevin Christopher Rancik

Dissertations and Theses

An increasing national focus on problems related to urban sprawl has fueled debate on the best way for urban areas to accommodate increasing populations. Portland, Oregon has attracted international attention for its growth policies, which are among the most stringent in the United States. Metro, the area's regional government in charge of long-range planning, has designated certain locations as regional centers where increased density and development are to occur. A logical question is whether or not these centers are developing as intended; do Metro's plans match reality on the ground? This study of Washington County, Oregon analyzes land value, building …

Potential For Speciation In Mammals Following Vast, Late Miocene Volcanic Interruptions In The Pacific Northwest, Ryan Thomas Mckenna

Dissertations and Theses

The impact of large-scale volcanic eruptions on landscapes can affect many processes ranging from interrupting or redirecting regional soil forming processes and hydrological systems to generating temporary changes in global climate. Though more studies exist every year, less is known of the direct impact of large-scale volcanic eruptions on ecosystems and extinction, while even less is known of their impact on speciation. In deposits throughout the Pacific Northwest a special combination and association of volcanic magnitude with palaeoecological yield frequently presents unique prospects for inquiry. In this study, particular attention is given to large, late Miocene ash-flow tuffs of central …

Spatial And Temporal Variability Of Glacier Melt In The Mcmurdo Dry Valleys, Antarctica, Matthew James Hoffman

Dissertations and Theses

In the McMurdo Dry Valleys, Victoria Land, East Antarctica, melting of glacial ice is the primary source of water to streams, lakes, and associated ecosystems. To better understand meltwater production, three hypotheses are tested: 1) that small changes in the surface energy balance on these glaciers will result in large changes in melt, 2) that subsurface melt does not contribute significantly to runoff, and 3) that melt from 25-m high terminal cliffs is the dominant source of baseflow during cold periods. These hypotheses were investigated using a surface energy balance model applied to the glaciers of Taylor Valley using 14 …

Effects Of Daily Social Support On Tension-Reduction Drinking, Deborah L. Brannan

Dissertations and Theses

Researchers have argued that in times of need having supportive, caring people available can make all the difference between achieving optimum health and well-being or suffering from mental or physical illness (Cobb, 1976; Sarason & Sarason, 1985; Thoits, 1986). The direct-effect model of support postulates that having the knowledge of available relationship resources (i.e., perceived support) and receiving benefits from those relationships (i.e., received support) both have beneficial effects on health behaviors and well-being (Cohen & Wills, 1985). According to the stress-buffering model, when stressors are encountered, the certainty of having available resources, as well as having tangible support resources, …

Deforestation, Drought And Humans: New Discoveries Of The Late Quaternary Paleoenvironment Of Rapa Nui (Easter Island), Candace Lynn Gossen

Dissertations and Theses

The mystery of the trees of Rapa Nui (Easter Island) is a complex problem within a dynamic ecosystem. With new physical cores from the volcanic crater lake Rano Kao, this dissertation uncovers a detailed 15,000 year ecological history of Easter Island and its climatic variability. New radiocarbon dating methods establish a more precise chronology which shows that the island before human habitation was very different than what we know today. It had a simple but prolific ecology that transitioned into a barren grassland. What factors caused the transition are unclear but are likely to be human related. As the forests …

The Role Of Microbial Endosymbionts In Sorghum Halepense Invasions: Evidence Of A New Invasion Strategy, Microbially Enhanced Competitive Ability (Meca), Marnie Erin Rout

Graduate Student Theses, Dissertations, & Professional Papers

Invasive plants can profoundly alter ecosystem processes, and tremendous economic costs are often associated with these disturbances. Attributes like higher growth rates, increased biomass, and enhanced chemical defenses have been documented in many invasive plants. When expanding into new ranges, these traits frequently allow invasive plants to outcompete native plant communities. Current theories suggest these invasive attributes are plant-regulated; however, my work shows that bacterial endosymbionts can regulate these traits in the invasive grass Sorghum halepense. Using culture and molecular approaches, I found the invasive grass harbors several bacterial organisms inside the roots and rhizomes. These bacterial endosymbionts were …

The Use Of Ct Analysis To Assess The Ages Of A Modern Human Tooth Sample: A Comparision With Dental Attrition And The Lamendin Method, Kristina Galdes

Graduate Student Theses, Dissertations, & Professional Papers

An analysis of 81 contemporary adult human teeth was conducted in order to determine which of three methods best determines age at death. The teeth were loaned from the University of Tennessee body farm to the University of Michigan’s Biomedical Research Laboratory and were comprised of central incisors, lateral incisors and canines. Each tooth was of known age and most were also associated with sex and ancestry. Three observers used Lovejoy’s (1985) method of dental attrition, the Lamendin et al. (1992) periodontosis method and micro computed tomography to determine how accurately each method was able to assess the ages at …