Physical Sciences and Mathematics Commons^™

Oregon State Rank Assessment For Steens Mountain Cushion Buckwheat (Eriogonum Ovalifolium Var. Rubidum), Lindsey K. Wise

Institute for Natural Resources Publications

Oregon state conservation status assessment for Steens Mountain Cushion Buckwheat (Eriogonum ovalifolium var. rubidum) using NatureServe methodology, 2026.

Oregon State Rank Assessment For Oregon Daisy (Erigeron Oreganus), Nora Dunkirk, Sue Vrilakas

Institute for Natural Resources Publications

Oregon state conservation status assessment for Oregon Daisy (Erigeron oreganus) using NatureServe methodology, 2026.

Oregon State Rank Assessment For Bensonia (Bensoniella Oregana), Nora Dunkirk, Sue Vrilakas, Gabriel Campbell

Institute for Natural Resources Publications

Oregon state conservation status assessment for Bensonia (Bensoniella oregana) using NatureServe methodology, 2026.

Detecting And Correcting Systematic Image Distortion In Digital Atomic-Resolution Images From Crystals: Projected Symmetry Of Graphite Calibration Samples For Scanning Prove Microscopy And Subperiodic Crystals For Aberration-Corrected Transmission Electron Microscopy, Tyler Michael Bortel

Dissertations and Theses

Though it is an impressive technology, Scanning Tunneling Microscopy (STM) produces images commonly plagued by small systematic errors, often called "drift". These effects have a variety of causes, most notably nonlinear behavior of piezoelectric actuator tubes responsible for the positioning of the scanning probe or sample. One result of these distortions is a potential incorrect classification of the symmetry groups and projected Laue classes of recorded images from crystals—made possible by using recently developed objective methods. An implementation of a known method for detecting and correcting these errors is presented. This method operates strictly in Fourier space so as to …

Oregon State Rank Assessment For Deschutes Milkvetch (Astragalus Tegetarioides), Nora Dunkirk, Gabriel Campbell, Sue Vrilakas

Institute for Natural Resources Publications

Oregon state conservation status assessment for Deschutes Milkvetch (Astragalus tegetarioides) using NatureServe methodology, 2026.

Oregon State Rank Assessment For Mt. Hood Bugbane (Actaea Laciniata), Nora Dunkirk

Institute for Natural Resources Publications

Oregon state conservation status assessment for Mt. Hood Bugbane (Actaea laciniata) using NatureServe methodology, 2026.

Block Kinematics, Interseismic Coupling And Fault Slip Rates In The Aegean Region From Gps And Earthquake Slip Vector Data: 1. Upper Plate Structures, Konstantinos Chousianitis, Sotiris Sboras, Volkan Özbey, Robert Mccaffrey, Semih Ergintav

Geology Faculty Publications and Presentations

We represent the active deformation of the Aegean region with an elastic‐kinematic block model composed of a finite number of rotating crustal blocks whose boundaries coincide with major active structures. A total of 832 GPS velocities and 146 earthquake slip vectors were inverted to provide estimates of block rotations and interseismic locking on block‐bounding faults so as to best reproduce the observed deformation field. Our regional model allowed us to derive a self‐consistent set of geodetic slip rates for upper plate faults and the Hellenic subduction system, the results of which are presented in a companion paper, and to determine …

Glacier Elevation Difference Data For The Conterminous U.S., Andrew G. Fountain, Bryce Allen Glenn, Christopher Mcneil, Brian Menounos

Geology Faculty Datasets

Historic and recent elevation data for the glaciers in the conterminous US were differenced to estimate glacier mass and volume change.

Historic glacier elevations were obtained from the USGS National Elevation Dataset (https://doi.org/10.15760/geology-data.04), a digitized product from the USGS 1:24,000 paper topographic maps that included the glacier extent (Gesch, 2007). Recent glacier elevations were derived from aerial lidar and from satellite radar. The lidar data were largely obtained from the USGS 3D Elevation Program (Stoker and Miller, 2022; US Geological Survey, 2024), and filtered by acquisition date using only those data collected between mid-summer and early autumn. The …

The Geologic History Of The Chehalis Forearc Basin, Washington State, Usa, R. L. Moe, J. Bershaw, L. M. Staisch, A. R. Streig

Geology Faculty Publications and Presentations

The Chehalis basin is located between the Cascade arc and the Coast Range in southwest Washington State. It consists of sedimentary and volcanic rocks deposited throughout the Cenozoic and is underlain by the Siletzia terrane, a thick, large igneous province accreted in the Eocene. Here, we constrain evolution of the Chehalis basin depocenter using isochore maps derived from isostatic gravity anomalies, borehole data, and stratigraphy for several time periods: the Eocene (47.6–36.8 Ma), the Oligocene (36.8–20 Ma), and the Neogene (20–0 Ma). Our results suggest that local subsidence is driven by deformation on faults that bound and intersect the basin. …

Block Kinematics, Interseismic Coupling And Fault Slip Rates In The Aegean Region From Gps And Earthquake Slip Vector Data: 2. Hellenic Subduction System, Konstantinos Chousianitis, Volkan Özbey, Sotiris Sboras, Robert Mccaffrey, Semih Ergintav

Geology Faculty Publications and Presentations

The Hellenic subduction system is the primary locus of Nubia‐Eurasia convergence, yet thedistribution of strain accumulation along it is still debated. Here, we invert 832 geodetic velocities and 146earthquake slip vectors to assess the spatial variability of interseismic locking and provide new constraints onthe rate of slip deficit accumulation. We find that the subduction interface beneath southwestern Peloponneseand across the area from offshore south Peloponnese to offshore southwest of western Crete hosts three patchesof low to moderate locking (0%–40%) at 10–50 km depth whose slip rate deficits account for ∼15–30% of thetotal plate convergence. The offshore weakly locked patches show …

A Dynamical Realization Of Holography In Cosmology From Hyperbolic General Relativity: Explicit Dimensional Reduction Via Curvature-Generated Shock Relaxation, Kiperman Jack

Physics Faculty Publications and Presentations

Holography asserts that the dynamics of a gravitational system may be determined by degrees of freedom associated with a lower-dimensional structure, rather than by independent volumetric variables. While this principle is well established in boundary-based constructions, its realization in cosmology has remained elusive due to the absence of fixed asymptotic boundaries. In this work, we present an explicit realization of holography in cosmology arising directly from the hyperbolic structure of general relativity. We show that the nonlinear evolution of the Einstein equations coupled to a scalar field generically produces a global control structure identified with the cosmological apparent horizon. By …

Anticodon Loop Remodeling And D-Stem Shape Drive The Specific Recognition Of Ann-Decoding Trnas For T6a Modification, Ana Kutchuashvili, Erik Scheleen, George Guynes, Junzhou Wu, Chi-Kong Chan, Peter Dedon, Dirk Iwata-Reuyl, Manal A. Swairjo

Chemistry Faculty Publications and Presentations

N6-threonylcarbamoyladenosine (t6A) is a universal transfer RNA (tRNA) modification essential for translational fidelity. The modification is installed at position 37 of ANN-decoding tRNAs (N is A, U, G, or C) by transfer of a threonylcarbamoyl moiety from a pathway intermediate, catalyzed in bacteria by the TsaBD complex. Despite the strict requirement for the 36-UAA-38 sequence in substrate tRNAs, the structural basis for this specificity has remained unclear. We determined cryo-EM structures of the Thermotoga maritima t 6A synthase bound to unmodified and to natively modified tRNA carrying the t 6A37 modification, at a nominal resolution of 3.2 A˚ . In …

(Re)Claiming Homeplace: Dance As Embodied Resistance & Healing For Health & Spatial Justice, Preeya G. Kannan

University Honors Theses

This thesis argues that dance functions as both an upstream public health intervention and a form of radical spatial resistance; creating healing, agency, and belonging among historically marginalized communities. Drawing on bell hooks' concept of homeplace, Jasbir Puar's assemblage theory, Nancy Krieger's eco-social theory, and Katherine McKittrick's Black geographies, I position the body as both an ecological and political landscape shaped by histories of colonialism, racial capitalism, displacement, and resilience.

Through this community-based participatory research study, Homeplace, I explore dance as a form of social prescription that centers liberation rather than pathology. Movement is often reduced in public health discourse …

Beyond The Best Prompt: A Coverage View Of Multilingual Reasoning, Harshiv Mistry

University Honors Theses

Multilingual LLMs reason more accurately in English than in other languages, and recent work links part of this gap to reasoning behavior: native-language traces contain fewer cognitive behaviors (verification, backtracking, subgoal setting, backward chaining) that support effective problem solving. We test whether prompting for these behaviors at inference time narrows the gap, across seven conditions varying chain-of-thought, instruction and reasoning language, and cognitive-behavior descriptions, on two models, three languages. We find that English-scaffolded reasoning is the strongest single strategy on both models, closing the Hindi gap on Qwen, though the explicit scaffold's value over plain chain-of-thought is model-dependent. Beyond aggregate …

Chondrites From Northwestern Nevada: The Jungo Dense Collection Area, Nico Morrelli

University Honors Theses

Dense collection areas are regions where meteorites are more frequently found, and can help researchers study the meteorite flux to Earth. The Jungo dry lake bed is a dense collection area (DCA) in Humboldt County, Nevada and is currently the recovery location of eleven officially classified meteorites. Five of these samples were classified as part of this work. All five are ordinary chondrites, two of which are likely paired with previously classified Jungo samples. Jungo 021 is likely paired with Jungo 005, and Jungo 017 is likely part of the previously established pairing group of Jungo 002, 003, and 004. …

Effects Of Fine Sediment On The Productivity Of Stream Ecosystems In The Pacific Northwest, Veena I. Davis

University Honors Theses

Salmon are important to the culture, ecosystem and economy of the Pacific Northwest. However, populations have declined significantly since European colonization. Salmon require specific conditions for each life stage and are highly sensitive to environmental stressors. Excess fine sediment is a leading form of pollution as it degrades salmon spawning habitat and the benthos upon which their main food source, stream insects, live. To evaluate the effect of sediment pollution on food availability for salmon smolt, we conducted an experiment  estimating the amount of stream insect biomass and calories lost due to sediment pollution. We counted insects on substrate samples …

Mycelial Modeling: Teaching Biology Students Statistical Modeling With Mushrooms, Colette Wolf

University Honors Theses

This paper summarizes and describes the development of a set of learning materials that were created to educate students and professionals from other fields in statistical modeling techniques. These materials are primarily aimed at biology students, but are still intended to be useful for anyone who is interested in incorporating decision trees and random forest models into their personal research in the future. By directing the reader towards the JMP software, these materials navigate around the statistical knowledge base and coding implementation practices that otherwise would serve as a barrier to learning statistical modeling techniques, and instead focus on the …

Pitching Fwar Vs Bwar As Predictors Of Team Success In The Mlb Regular Season, Jason Lee

University Honors Theses

Pitching Wins Above Replacement (WAR) is an area of sabermetrics capable of being used to predict regular season success in Major League Baseball. Fangraphs WAR (fWAR) and Baseball Reference WAR (bWAR) were used to construct regression models to predict regular season winning percentage, to build logistic models to establish a relationship between pitching WAR and the probability to win an individual regular season game, and to overlay density plots to consider WAR accumulation by pitching role and observe the difference of impact between starter and relief pitchers. This research finds that while pitching fWAR and pitching bWAR are both statistically …

Assessing Spatial Distribution Of Plausible Earthquake-Triggered Landslides Relative To Ca. 1000 Ybp Earthquake On The Gales Creek Fault, Jacqueline Rheingans

University Honors Theses

Modern coseismic landslides cluster near the surface trace of the fault that ruptured, suggesting that clustering of paleolandslides may record information about paleoearthquakes. This study documents the pattern of prehistoric landslides near the Gales Creek Fault (GCF), northwest Oregon, to assess whether it reflects an independently known paleoearthquake. The GCF is located northwest of Portland through the Cascadia fore-arc basin where landslides are often triggered by intense rainfall during the wet season or potentially by seismic shaking on the megathrust or on crustal faults. In order to understand how a seismic event on the GCF will impact landslide distribution I …

Custom Sbc Gps Tracking And Geocaching Carputer Software Development And Implementation, Joshua A. Davis

University Honors Theses

This thesis argues that hardware-integrated capstone projects develop software engineering skills that traditional coursework cannot replicate. A team of eight developers built a GPS tracking system on a Raspberry Pi 4 over two academic terms, integrating real-time position streaming, the APRS amateur radio protocol for network-independent location sharing, and PostGIS spatial queries for "new road" detection. The system implements SmartBeaconing for adaptive GPS data reduction, achieving approximately 80% storage savings while preserving route fidelity. The project exposed challenges absent from classroom assignments: hardware debugging without stack traces, cross-layer integration failures, and coordination overhead when deploying to unfamiliar architecture; demonstrating that …

Effects Of Changing Fire Regimes On Black Huckleberry Habitat Suitability, Emily Labarge

University Honors Theses

Black huckleberries are a significant cultural, ecological, and economic species in the Pacific Northwest. Historically, black huckleberries were tended with cultural fire by Indigenous peoples, and now also hold importance as a resource in the non-timber forest product economy. Research has begun on the impacts of climate change on suitable black huckleberry habitat and on changing fire regimes, but not in relation to each other. To address this gap, I examined the area of overlap between suitable black huckleberry habitat and fire burn probability into mid-century climate projections. I determined the current ownership entities with management jurisdiction in areas with …

Rapid-Prototyping Nanofabrication: Lcd-Based Projection Lithography And Physical Vapor Deposition, Sabeel Saleem Mohammmed

University Honors Theses

The semiconductor industry's continued growth, driven in large part by demand for artificial intelligence hardware, has highlighted the need for greater workforce development in regions adjacent to major fabrication centers like Oregon's Silicon Forest. This capstone project lays the groundwork for a small scale and student led semiconductor fabrication lab at Portland State University by demonstrating two of the core steps in chip manufacturing: photolithography and thin film deposition. Rather than relying on conventional fixed reticles, this work explores a unique, low cost approach to patterning that uses an ultraviolet-compatible liquid crystal display (LCD) as a programmable reticle, allowing arbitrary …

A Novel, Embedding-Based Approach To Longitudinal Survey Data Imputation, Julia Rezvani

University Honors Theses

Longitudinal surveys are ubiquitous in the social sciences as a means of tracking changes in behavior and opinions with time and identifying potential causal mechanisms. These surveys are frequently plagued by missing data and semantic drift, both of which limit their effectiveness and scientific utility. Imputation algorithms allow researchers to fill gaps in collected survey datasets, imperfectly reconstructing lost data. Although deep learning algorithms have been used in imputation to great success, approaches which simultaneously leverage the semantic and temporal structure of longitudinal surveys have not yet been developed. We propose a novel imputation architecture which is capable of leveraging …

Projected Climate Change Impacts On Soil Greenhouse Gas Emissions From A Restored Freshwater Marsh, Annika Hendrickson

University Honors Theses

Wetlands provide valuable ecosystem services, one of which is a wetlands ability to sequester carbon. Climate change and human land use threaten a wetlands ability to do so. Globally, 21% of wetlands have been lost since the 1700s. As a result, restoration of wetlands has been increasing. However, wetlands in the process of restoration emit more methane than degraded ones, and as the climate continues to change, these fluxes could respond. Projected sea level rise is expected to cause salt water to infiltrate coastal freshwater systems, increasing the salinity. Past research has found that increased salinity has led to suppressed …

Uniform Stability Of Katyusha In Strongly-Convex Settings, Don Li

University Honors Theses

Acceleration of convergence and reduction of variance constitute a trade-off in the design of stochastic optimization machine learning algorithms. Katyusha was introduced to address this trade-off, synthesizing Nesterov Accelerated Gradient (NAG) and Stochastic Variance-Reduced Gradient (SVRG) into a single first-order optimizer with promising empirical performance. However, the generalization properties of Katyusha remain largely unexplored. We conjecture that, in the smooth quadratic regime (i.e., under assumptions of strong convexity and smoothness of the loss function, and boundedness of gradients), Katyusha is uniformly stable in the sense of Bousquet and Elisseeff. Instantiating our framework for NAG, we extend the use of Lyapunov …

Oregon State Rank Assessment For Willamette Navarretia (Navarretia Willamettensis), Nora Dunkirk

Institute for Natural Resources Publications

Oregon state conservation status assessment for Willamette Navarretia (Navarretia willamettensis) using NatureServe methodology, 2026.

The Method Of Periodic Averaging Applied To Reduced Coupled Mode Theory Models For Fiber Laser Amplifiers, Rebecca Nicole Bryant

Dissertations and Theses

Fiber laser amplifier (FLA) models are often implemented without rigorous mathematical justification or thorough numerical validation. Without a proper theoretical basis for assumptions and approximations, or a technical analysis of model performance, there is significant uncertainty about the limitations of any given reduced model and its suitability for an application. This research aims to address the lack of comprehensive assessment of FLA models by directly comparing distinct models and recommending a mathematical alternative to replace heuristic model-reduction techniques. The work in this dissertation is divided into two projects: a comparative study that uses existing FLA models to assess the validity …

Assessment Of The Readiness Of Architectural Design Companies To Adopt Eco-Friendly Nanotechnologies In Sustainable Building Design, Ashwaq Essa Al Khalil

Dissertations and Theses

Nanotechnology is emerging as a promising innovation in sustainable architectural design, although its adoption remains slow. Research highlights the advantages of incorporating nanotechnologies in architecture, including improved material performance, enhanced thermal efficiency, reduced energy consumption, improved durability, and progress toward the Sustainable Development Goals (SDGs). These advantages make nanomaterials a promising solution for sustainable building design, particularly in hot-climate regions where energy consumption and carbon emissions associated with conventional building design practices remain major concerns.

Despite this potential, nanotechnology adoption in architecture faces several challenges, including limited real-world applications, slow diffusion in practice, and persistent organizational, economic, and regulatory barriers. …

Introduction To Mathematical Analysis Ii, Beatriz Lafferriere, Gerardo Lafferriere, Mau Nam Nguyen

PDXOpen: Open Educational Resources

These lecture notes complement the book Introduction to Mathematical Analysis I, Third Edition, with sections on integration, numerical series, series of functions, and selected advanced topics. Together, both volumes support a one semester or two-quarter course on introductory mathematical analysis.

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Investigating An Energy-Preserving Spectral Finite Difference Numerical Method For A Wave Equation On The Metric Graph, Tue Minh Tran

University Honors Theses

To investigate the accuracy and long-term energy conservation of a spectral finite difference numerical method for a wave equation on metric graphs. In conservative systems, numerical methods should preserve total energy. However, explicit finite difference methods require impractically small space steps and exhibit energy drift at end points. To address these limitations, a spectral finite difference method is implemented using a Fourier transformation. This semi-spectral method improves stability at endpoints while maintaining second-order accuracy, achieving an overall error of O(∆t²). We implement the semi-spectral method on the IEEE14 metric graph and provide visuals showing the initial condition …