Digital Commons Network^™

Numerical Modeling Of Electromagnetic Scattering In Explosive Granular Media, Garth Sundberg

Dissertations and Theses

Terahertz (THz) reflection and transmission spectroscopy is a promising new field with applications in imaging and illicit material detection. One particularly useful application is for the detection of improvised explosive devices (IEDs) which is a favorite weapon of global terrorists. Explosive materials have been shown to have a unique spectral signature in the THz band which can be used to identify the explosives. However, the initial measurements performed on the explosive samples do not account for the modulation of the spectral features by random scattering that will be prevalent with actual samples encountered in applications. The intent of this work …

Diatom-Based Stream Bioassessment: The Roles Of Rare Taxa And Live/Dead Ratio, Nadezhda Dimitrova Gillett

Dissertations and Theses

It is unclear whether accounting for the number of rare taxa or differentiating live (cells with visible chloroplasts) and dead (empty cells) diatoms would enhance the accuracy and precision of diatom-based stream bioassessment. My dissertation research examines whether the number of rare taxa and percentage (%) live diatoms can be used as indicators of human disturbance in streams/rivers. To address my objectives, I analyzed two datasets collected at different spatial scales. The large scale dataset was collected over the course of five years and included more than 1300 sites and over 200 environmental variables from 12 Western US states (US …

Efficient Encoding Of Vocalizations In The Auditory Midbrain, Lars Andreas Holmstrom

Dissertations and Theses

An important question in sensory neuroscience is what coding strategies and mechanisms are used by the brain to detect and discriminate among behaviorally relevant stimuli. To address the noisy response properties of individual neurons, sensory systems often utilize broadly tuned neurons with overlapping receptive fields at the system's periphery, resulting in homogeneous responses among neighboring populations of neurons. It has been hypothesized that progressive response heterogeneity in ascending sensory pathways is evidence of an efficient encoding strategy that minimizes the redundancy of the peripheral neural code and maximizes information throughput for higher level processing. This hypothesis has been partly supported …

Use Of Media Technologies By Native American Teens And Young Adults: Evaluating Their Utility For Designing Culturally-Appropriate Sexual Health Interventions Targeting Native Youth In The Pacific Northwest, Stephanie Nicole Craig Rushing

Dissertations and Theses

American Indian and Alaska Native (AI/AN) youth are disproportionally burdened by high rates of sexually transmitted infections and teen pregnancy, heightening their need for sexual health interventions that are aligned to their unique culture and social context. Media technologies, including the Internet, cell phones, and video games, offer new avenues for reaching adolescents on a wide range of sensitive health topics. While several studies have informed the development of technology-based interventions targeting mainstream youth, no such data have been reported for AI/AN youth. To fill this gap, I: a) quantified media technology use in a select group of AI/AN teens …

The Micropivot : An Integrated Particle Image Velocimeter And Optical Tweezers Instrument For Microscale Investigations, Nathalie Neve De Mevergnies

Dissertations and Theses

This dissertation describes the development of a device capable of suspending a microscale object in a controlled flow. The uPIVOT is a system integrating two laser-based techniques: micron particle image velocimetry (uPIV) and optical tweezers (OT). The OT allows the suspension and manipulation of micron-sized objects such as microspheres or biological cells. uPIV provides imaging of the suspended object and velocity measurements from which fluid induced stresses can be determined. Using this device, we measured fluid velocities around an optically suspended polystyrene microsphere (an experimental first) and studied the interaction between two particles suspended in a uniform flow. The results …

Evolutionary Dynamics In Molecular Populations Of Ligase Ribozymes, Carolina Diaz Arenas

Dissertations and Theses

The emergence of life depended on the ability of the first biopolymer populations to thrive and approach larger population sizes and longer sequences. The evolution of these populations likely occurred under circumstances under which Muller's Ratchet in synergism with random drift could have caused large genetic deterioration of the biopolymers. This deterioration can drive the populations to extinction unless there is a mechanism to counteract it. The effect of the mutation rate and the effective population size on the time to extinction was tested on clonal populations of B16-19 ligase ribozymes, evolved with the continuous evolution in vitro system. Populations …

Parental Differential Treatment (Pdt) Of Siblings: Examining The Impact And Malleability Of Differential Warmth And Hostility On Children's Adjustment, Brianne H. Kothari

Dissertations and Theses

Parental differential treatment (PDT), the within-family differences in parenting experienced by siblings (Rivers & Stoneman, 2008), has been linked to detrimental adjustment outcomes for children (e.g., Conger & Conger, 1994). The primary goal of this research was to more closely examine how differential treatment in two domains of parent-child relations-displays of warmth and hostility- were associated with child outcomes. A secondary data analysis was conducted on a Randomized Controlled Trial (RCT) of a parent training intervention. Participants in this sample were high risk children and families, and they were randomly assigned to one of three groups: an intensive parent training …

Effects Of Biochar-Amended Soil On The Water Quality Of Greenroof Runoff, Deborah Aileen Beck

Dissertations and Theses

As the numbers of installed greenroofs continue to grow internationally, designing greenroof growing media to reduce the amount of nutrients in the stormwater runoff is becoming essential. Biochar, a carbon-net-negative soil amendment, has been promoted for its ability to retain nutrients in soils and increase soil fertility. This study evaluated the effect on water quality of greenroof runoff after adding biochar to a typical extensive greenroof soil. Prototype greenroof trays with and without 7% biochar (by weight) were planted with sedum or ryegrass, with barren soil trays for controls. The greenroof trays were subjected to two sequential 2.9 in/hr rainfall …

Biomechanical Assessment Of Parkinson's Disease, Edward A. Katz

Dissertations and Theses

Parkinson's disease is a chronic neurological disorder affecting hundreds of thousands of Americans. The current best practice for assessment of this disease is a clinical examination and subjective rating using the Unified Parkinson's Disease Rating Scale. Such ratings are coarse scaled, subject to rater bias, and costly. Instruments which provide objective measurements of disease state can eliminate rater bias, provide repeatable data, and increase the frequency and responsiveness of subject assessments, expediting the validation of new therapies and treatments. This thesis describes the design and implementation of a battery of bio-mechanical devices suitable for clinical and in home use, including …

Thermodynamic Effects Of 5' And 3' Single Strand Dangling Ends On Short Duplex Dna, Rebekah Dickman

Dissertations and Theses

Differential scanning calorimetry (DSC) melting analysis was performed on 27 short double stranded DNA duplexes containing 15 to 25 base pairs and short single stranded overhangs from one to 10 bases, on both ends. Molecules have two 5' dangling ends or one 5' and one 3' dangling end. For these molecules the duplex region was incrementally reduced from 25 to 15 base pairs with increased length of the dangling ends from one to 10 bases. A third set of molecules contained 21 base pair duplexes with a four base dangling end on either the 5' or 3' end. Blunt ended …

Do Parents Matter? Parental Attachment And Its Effect On Becoming Independent In Emerging Adulthood, Cara Joy Copeland

Dissertations and Theses

Data from the National Longitudinal Study of Adolescent Health Waves I and III are used to estimate the effect of parental attachment on independence in emerging adults ages 18 to 27. The nature of independence focused on living in a place of their own and not receiving financial support from parents, which described about half of the sample. The study finds that emerging adults who, in their youth, expressed high attachments to their parents, were slightly less likely to become independent as emerging adults. Rather, age and gender are greater positive predictors of independence.

An Environment-Based Education Approach To Professional Development: A Mixed Methods Analysis Of The Creeks And Kids Watershed Workshop And Its Impact On K-12 Teachers, Tiffany Bridgette Austin

Dissertations and Theses

This research is an in-depth study of an environment-based education (EBE) professional development program titled "Creeks and Kids" that models how to employ thematic instruction about watersheds using the environment of a school and its community as a context to integrate teaching and learning about water across core subject areas. This case study investigates the EBE characteristics of the Creeks and Kids Workshop and explores how they adhere to the National Research Council's Standards for Professional Development for Teachers of Science. A mixed-methods analysis gathered qualitative data about the overall experience of teacher-participants during the Creeks and Kids Workshop and …

Functional Separation Of Multimodular Type I Pks Polypeptides By Utilizing Matched Docking Domains From A Heterologous Pks System, John Kam Yan

Dissertations and Theses

Bacterial type I modular polyketide synthases (PKS) are large multifunctional enzyme systems responsible for the biosynthesis of complex polyketide natural products such as erythromycin, pikromycin, and borrelidin. Type I systems are comprised of a loading module which generally selects an appropriate acyl group starter unit, and multiple discrete extension modules, responsible for each single round of acyl group incorporation into the final polyketide core structure. These modules can exist naturally as either single discrete polypeptides, such as modules 5 and 6 from the pikromycin PKS (PikA3 and PikA4 respectively), or as multimodular polypeptides fused together by short intrapolypeptide linkers such …

The Effects Of Animals On Children's Development Of Perspective-Taking Abilities, Mika Maruyama

Dissertations and Theses

Although attention to the effects of child-animal interactions on children's development has increased in the last three decades, developmental psychology has not attended to the importance of the effects of animals on children's development. There is a need to consider the possible impacts of animals as significant social partners for children's socioemotional development. The current study, through survey questionnaires and interview methods, investigated whether interacting with animals, especially when children have responsibilities for the welfare of pets and perhaps have formed strong attachments with pets, will promote children's socio-emotional development, specifically their abilities to take the perspective of others. Sixty-five …

Genomic And Hormonal Components Of Altered Developmental Pathways In The Annual Killifish, Austrofundulus Limnaeus, Benjamin M. Pri-Tal

Dissertations and Theses

The annual killifish, Austrofundulus limnaeus, may enter embryonic diapause at three distinct points of development, termed diapause I, II, and III. Previous studies suggest a role for steroid hormones in the regulation of diapause in annual killifish. This study concerns the hormonal and genomic components involved in the developmental decision to enter or escape diapause II from both a maternal and embryonic perspective. Steroid hormone levels were measured in tissues isolated from adult female fish that were producing either high or low proportions of escape embryos. Levels of steroid hormones were also measured in new fertilized embryos that were known …

Spatial Segregation Of The Sexes In A Salt Marsh Grass Distichlis Spicata (Poaceae), Charlene Ashley Mercer

Dissertations and Theses

Understanding the maintenance of sexual systems is of great interest to evolutionary and ecological biologists because plant systems are extremely varied. Plant sexual systems have evolved to include not only complete plants with both male and female reproduction occurring on one plant (i.e., monoecious and hermaphroditic) but also plants with male and female function on separate plants (dioecious). The dioecious reproductive system can be used to test theories on niche differentiation given that having separate plants potentially allows for the exploitation of a broader niche. This increase in the realized niche is due to the ability for separate sexes to …

Beyond The "Stalled Revolution": Stay-At-Home Fathers, Gender Identity And The Division Of Household Labor, Aundrea Janae Snitker

Dissertations and Theses

The purpose of this thesis is to explore how stay-at-home fathers view their role as the primary caregiver, and how they encounter opposing masculinity issues. This is explored through discussion about daily life, the decision to stay home, and household labor, a particularly interesting reflection of gender roles and equality. The two research questions used to explore this included: How do stay-at-home fathers understand their masculinity and social role? How does talk about the negotiation of household labor in stay-at-home father/career mother families illustrate masculinity issues? Through an analysis of interviews of eight present or past stay-at-home fathers, I capture …

The Function Of An Alternate Tfb From Pyrococus Furiosus And The Orientation Of The Tfb B-Reader Within Archaeal Transcription Initiation Complexes, Michael Micorescu

Dissertations and Theses

The genome of the hyperthermophile archaeon Pyrococcus furiosus encodes two transcription factor B (TFB) paralogs, one of which (TFB1) was previously characterized in transcription initiation. The second TFB (TFB2) is unusual in that it lacks recognizable homology to the archaeal TFB/eukaryotic TFIIB B-reader (also called the B-finger) motif. TFB2 functions, though poorly, in promoter-dependent transcription initiation. Domain swaps between TFB1 and TFB2 showed that the low activity of TFB2 is determined mainly by its N terminus. The low activity of TFB2 in promoter opening and transcription can be partially relieved by transcription factor E (TFE). The results indicate that the …

Designing Exhibits For Gender Equity, Toni Nicole Dancu

Dissertations and Theses

Gender equity has been a national and global aim for over half a century (Ceci & Williams, 2007; National Center for Education Statistics, 2003; National Science Board, 2008). While gains have been made, one area where inequity remains is spatial reasoning ability, where a large gender gap in favor of males has persisted over the years (Else-Quest, Linn, & Shibley Hyde, 2010; National Science Board, 2008; Ruble, Martin, & Berenbaum, 2006). This gender gap in spatial reasoning has had substantial societal impact on the career interests of females in areas of Science, Technology, Engineering, and Math (STEM), contributing to the …

Genetic Patterns Of Dispersal And Colonization During Initial Invasion And Spread Of An Invasive Grass, Brachypodium Sylvaticum, Alisa Paulsen Ramakrishnan

Dissertations and Theses

Evolution of genotypes during range expansion is driven in part by colonization dynamics. I investigated genetic patterns of colonization and dispersal during initial expansion of an invasive bunchgrass, Brachypodium sylvaticum, into Oregon. Using microsatellite markers, I sampled plants at two different scales: at regular intervals along three parallel roads spanning about 30km, and in populations identified throughout Oregon. I also collected field-generated progeny from a subset of populations and used molecular identification of outcrossing events to estimate selfing rates in both central and peripheral populations. Dispersal patterns were similar at both scales, with non-contiguous dispersal responsible for colonization of new …

Comparison Of Microshear Bond Strength And Morphological Changes Between Active And Passive Application Of 4th Generation Etch-And-Rinse Etchant On Enamel, Sophia Tuyet-Nhi Trieu

Dissertations and Theses

Over 200 million dental restorations are performed each year in America. A dental restoration require a strong bonding of restoration to tooth structure and relies on the dental adhesive to create this mechanical and chemical bonding. Dental adhesion or bonding is the process of forming an adhesive joint between the composite and tooth substrate: dentin or enamel. Clinical problems such as microleakage at the restoration tooth interface, influx of fluids, or bacteria growth at the cavity wall can be prevented with adhesives that obtain a more intimate bonding. Longevity of the restoration can be enhanced by the adhesive that creates …

Modeling Terahertz Diffuse Scattering From Granular Media Using Radiative Transfer Theory, Kyung Moon Nam

Dissertations and Theses

Terahertz (THz) spectroscopy can potentially be used to probe and characterize inhomogeneous materials, however spectroscopic identification of such materials from spectral features of diffuse returns is a relatively underdeveloped area of study. In this thesis, diffuse THz scattering from granular media is modeled by applying radiative transfer (RT) theory for the first time in THz sensing. Both classical RT theory and dense media radiative transfer (DMRT) theory based on the quasi-crystalline approximation (QCA) are used to calculate diffuse scattered intensity. The numerical solutions of the vector radiative transfer equations (VRTE) were coded and calculated in MATLAB. The diffuse scattered field …

Stochastic Orders In Heterogeneous Samples With Applications, Maochao Xu

Dissertations and Theses

The statistics literature has mostly focused on the case when the data available is in the form of a random sample. In many cases, the observations are not identically distributed. Such samples are called heterogeneous samples. The study of heterogeneous samples is of great interest in many areas, such as statistics, econometrics, reliability engineering, operation research and risk analysis.

Stochastic orders between probability distributions is a widely studied concept. There are several kinds of stochastic orders that are used to compare different aspects of probability distributions like location, variability, skewness, dependence, etc.

In this dissertation, most of the work is …

Simplified Reversed Chloroquines To Overcome Malaria Resistance To Quinoline-Based Drugs, Bornface Gunsaru

Dissertations and Theses

Malaria is a major health problem, mainly in developing countries, and causes an estimated 1 million deaths per year. Plasmodium falciparum is the major type of human malaria parasite, and causes the most infections and deaths. Malaria drugs, like any other drugs, suffer from possible side effects and the potential for emergence of resistance. Chloroquine, which was a very effective drug, has been used since about 1945, but its use is severely limited by resistance, even though it has mild side effects, and is otherwise very efficacious. Research has shown that there are chloroquine reversal agents, molecules that can reinstate …

Engaging A Systems Approach To Evaluate Domestic Violence Intervention With Abusive Men: Reassessing The Role Of Community, Courtenay Silvergleid Wallpe

Dissertations and Theses

The domestic violence movement has had remarkable success illuminating the scope, prevalence and consequences of battering, but has been more limited in its ability to successfully intervene and prevent abuse of women by their intimate male partners. Surprisingly, there has been little research directed at understanding why intervention strategies with perpetrators are only minimally effective. Studies have focused on assessing the degree to which and for whom individual components such as arrest, prosecution and psycho-educational programs for abusive men are successful, but few explorations have attempted to describe limitations and challenges to the domestic violence intervention 'system as a whole'. …

La Palabra Es Salud: A Comparative Study Of The Effectiveness Of Popular Education Vs. Traditional Education For Enhancing Health Knowledge And Skills And Increasing Empowerment Among Parish-Based Community Health Workers (Chws), Noelle Wiggins

Dissertations and Theses

Popular education is a mode of teaching and learning which seeks to bring about more equitable social conditions by creating settings in which people can identify and solve their own problems. While the public health literature offers evidence to suggest that popular education is an effective strategy for increasing empowerment and improving health, there have been no systematic attempts to compare the outcomes of popular education to those of traditional education. The goal of La Palabra es Salud was to conduct such a comparison among Latino, parish-based Community Health Workers (CHWs). The study employed a quasi-experimental design, mixed methods, and …

The Law And Politics Of Us Participation In The Un Convention On The Rights Of Persons With Disabilities, Professor Michael Stein, Janet E. Lord, Penelope J.S. Stein

Articles

No abstract provided.

Symmetry And Stability Of Homogeneous Flocks, J. J. P. Veerman

Mathematics and Statistics Faculty Publications and Presentations

The study of the movement of flocks, whether biological or technological, is motivated by the desire to understand the capability of coherent motion of a large number of agents that only receive very limited information. In a biological flock a large group of animals seek their course while moving in a more or less fixed formation. It seems reasonable that the immediate course is determined by leaders at the boundary of the flock. The others follow: what is their algorithm? The most popular technological application consists of cars on a one-lane road. The light turns green and the lead car …

Expressive Motion Synthesis For Robot Actors In Robot Theatre, Mathias I. Sunardi

Dissertations and Theses

Lately, personal and entertainment robotics are becoming more and more common. In this thesis, the application of entertainment robots in the context of a Robot Theatre is studied. Specifically, the thesis focuses on the synthesis of expressive movements or animations for the robot performers (Robot Actors). The novel paradigm emerged from computer animation is to represent the motion data as a set of signals. Thus, preprogrammed motion data can be quickly modified using common signal processing techniques such as multiresolution filtering and spectral analysis. However, manual adjustments of the filtering and spectral methods parameters, and good artistic skills are still …

Occurrence And Concentrations Of Caffeine In Seawater From The Oregon Coast And Potential Effects On The Dominant Mussel, Mytilus Californianus, Zoe Rodriguez Del Rey

Dissertations and Theses

Caffeine, a biologically active drug with many known molecular targets, is recognized as a contaminant of aquatic systems including marine systems. Although the concentrations of caffeine reported from aquatic systems are low (ng/L to μ/L), harmful ecological effects not detected by traditional toxicity tests could occur as a result of caffeine contamination. The goals of this thesis project were to: 1) quantify concentrations of caffeine occurring in the coastal ocean off of the Oregon Coast and to determine if higher levels were correlated with proximity to caffeine pollution sources; and 2) investigate the sub-lethal cellular toxicity of environmentally relevant concentrations …