Physical Sciences and Mathematics Commons^™

The Discontinuous Petrov–Galerkin Method, Leszek Demkowicz, Jay Gopalakrishnan

Mathematics and Statistics Faculty Publications and Presentations

The discontinuous Petrov–Galerkin (DPG) method is a Petrov–Galerkin finite element method with test functions designed for obtaining stability. These test functions are computable locally, element by element, and are motivated by optimal test functions which attain the supremum in an inf-sup condition. A profound consequence of the use of nearly optimal test functions is that the DPG method can inherit the stability of the (undiscretized) variational formulation, be it coercive or not. This paper combines a presentation of the fundamentals of the DPG ideas with a review of the ongoing research on theory and applications of the DPG methodology. The …

Expanding And Mainstreaming Sociohydrology Toward Transdisciplinary Praxis, Shinichiro Nakamura, Heidi Kreibich, Melissa Haeffner, Jenia Mukherjee, Giuliano Di Baldassarre, Maiko Sakamoto, Mikiko Sugiura, Günter Blöschl, Taikan Oki, Murugesu Sivapalan

Environmental Science and Management Faculty Publications and Presentations

Since its development in the early 2010s, sociohydrology has deepened our understanding of the long-term coevolution of humans and water by integrating insights from both the natural and social sciences, while also fostering an interdisciplinary community. Its modus operandi to date has been to focus on emergent phenomena, manifesting as unintended consequences, in a variety of contexts. The compound disaster that struck Japan’s Noto Peninsula in 2024, and similar experiences in other parts of the world, underscore the urgent need for systemic approaches that are co-developed by academia and practitioners and focus on context-specific solutions. This perspective piece thus calls …

Robust Contraction Decomposition For Minor-Free Graphs And Its Applications, Bandyapadhyay Sayan, William Lochet, Daniel Lokshtanov, Dániel Marx, Pranabendu Misra, Multiple Additional Authors

Computer Science Faculty Publications and Presentations

We prove a robust contraction decomposition theorem for H-minor-free graphs, which states that given an H-minor-free graph G and an integer p, one can partition in polynomial time the vertices of G into p sets Z₁,… ,Z_p such that tw(G/(Z_i ⧵ Z')) = O(p + |Z'|) for all i ∈ [p] and Z' ⊆ Z_i. Here, tw(⋅) denotes the treewidth of a graph and G/(Z_i ⧵ Z') denotes the graph obtained from G by contracting all edges with both endpoints in Z_i ⧵ Z'. Our result generalizes earlier results by Klein [SICOMP 2008] and Demaine et al. [STOC 2011] based …

Potent Acridone Antimalarial Against All Three Life Stages Of Plasmodium, Papireddy Kancharla, Rozalia A. Dodean, Yuexin Li, Xiaowei Zhang, Sean Kelly, Jordan Charlton, Angley Binauhan, Laurize Garcia, Diana Caridha, Jane X. Kelly, Multiple Additional Authors

Chemistry Faculty Publications and Presentations

New antimalarial therapeutics ideally should target all three major life cycle stages. Here we present an acridone antimalarial chemotype that is potent against blood, liver, and mosquito stages of malaria parasites, with the potential for single-dose cure of bloodstream infections, radical cure of liver infections, and blocking of transmission to mosquitoes. Attributes of lead candidate T111 include potent in vitro activity against cultured parasites, ex vivo activity against clinical isolates, oral single dose cure in an asexual blood stage rodent model, inhibition of sexual blood stage parasites, activity against relapsing parasites in non-human primate liver cells, prevention of parasite development …

Bahadur Representations For Canonical Quantile Regression: A Correction And Extension, Stephen Portnoy

Mathematics and Statistics Faculty Publications and Presentations

Portnoy (2022) introduced a version of Canonical Correlation anal- ysis based on Regression Quantiles. The proof of the asymptotic convergence of the estimators contained some gaps. A new proof is developed using Bahadur representations to obtain asymptotic represen- tations for the Canonical Regression Quantile components with error uniformly O_p (n^-1/4 log n). These innovative representations justify approximations and automatically provide joint convergence in dis- tribution. This enables an inductive argument to obtain asymptotic results for all components. These novel Bahadur approximations may have more general application and interest.

Homework, Households, And Hurdles: The Unexpected Drivers Of Student Graduation Perceptions, Daniel Alhassan, Zahra Fatah, Priscilla Mansah Codjoe, Caroline Bena Kuno, Dorcas Ofori-Boateng

Mathematics and Statistics Faculty Publications and Presentations

Students’ perceptions of their likelihood to graduate are important determinants of their academic engagement, yet these perceptions remain understudied. This study, which is based on the 2021 Monitoring the Future survey of 8th- and 10th-grade students in the United States, uses machine learning algorithms to identify the most important factors that influence these perceptions. Among the tested models, random forest provided the best classification performance. Using permutation-based feature importance, we identified frequent participation in schoolwork, maternal education, paternal education, and homework completion as the most important predictors of students’ graduation perceptions. These results highlight the importance of targeted and well-coordinated …

Kolmogorov–Smirnov-Based Edge Centrality Measure For Metric Graphs, Christina Durón, H. Kravitz, Moysey Brio

Mathematics and Statistics Faculty Publications and Presentations

In this work, we introduce an edge centrality measure for the Helmholtz equation on metric graphs, a particular flow network, based on spectral edge energy density. This measure identifies influential edges whose removal significantly changes the energy flow on the network, as indicated by statistically significant p-values from the two-sample Kolmogorov–Smirnov test comparing edge energy densities in the original network to those with a single edge removed. We compare the proposed measure with eight vertex centrality measures applied to a line graph representation of each metric graph, as well as with two edge centrality measures applied directly to each …

Population Genomic Investigation Of The Oregon Slender Salamander (Batrachoseps Wrighti) Reveals Suburban Populations Are Remnants, Not Recent Introductions, Clare Yang, Laura Guderyahn, Charlotte Corkran, Steven Wagner, Lauren M. Chan

Environmental Science and Management Faculty Publications and Presentations

In the face of urbanization and anthropogenic change, some native species persist while others are lost. Understanding native populations, particularly in marginal habitat, can lend insights into the effects of habitat change. The Oregon Slender Salamander (Batrachoseps wrighti) is endemic to the late-successional forests of the Cascade Range in Oregon and has declined due to land use change. In 2007, several populations of the Oregon Slender Salamander were found within highly human-modified localities in the Portland Metropolitan Region. We investigate whether these, and other newly discovered suburban populations, represent remnant populations that persisted in the face of habitat …

The Discovery, Communication, And Implementation Of New Geologic Findings: Examining The Cascadia Earthquake, Saylor Brainard

University Honors Theses

The Cascadia Subduction Zone, located off the Coast of the Pacific Northwest, is at risk of generating a 9.0 magnitude earthquake in the near future. Despite its significance, the discovery of the seismic potential of Cascadia didn't occur until 1987, when geologist Brian Atwater searched for non-traditional forms of earthquake evidence. As decades of continued research fleshed out Atwater's initial discovery, the implications associated with the discovery became apparent, presenting Washington and Oregon with the high probability that a massive earthquake will take place within the next century. Communicating the severity of this geologic discovery to both the public and …

Pvc Biodegradation Potential Of Native Fungal Strains From Mt. Hood National And Tillamook State Forests, Bristol Ozturgut

University Honors Theses

Polyvinyl chloride (PVC) is a toxic, degradation-resistant environmental waste product. Recent research has revealed fungal enzymatic activity capable of biodegrading plastics. As PVC infiltrates local environments, it becomes imperative to determine the adaptability of local fungi to PVC substrates. In this experiment, 100 local native fungal strains sampled from the Tillamook State and Mt. Hood National forests and one commercial strain of common oyster mushroom were investigated for their ability to colonize and digest PVC by direct isolation on 0.1% and 0.2% PVC-enriched limited growth media. Substrates for positive cultures were imaged using Fourier transform infrared spectroscopy to analyze potential …

Characterization Of The Quaternary Active Twin Lakes Fault, Mount Hood, Oregon, Johnathan Peterson

University Honors Theses

The High Cascades chain of volcanoes results from Cascade Arc volcanism and is responsible for the generation of the highest topography in the state of Oregon. Surrounding Mt. Hood at the crest of the Cascade chain in northern Oregon is the Mt. Hood Fault Zone, an extensional fault zone of generally north-south trending normal faults that down-drop this high volcanic topography. The Twin Lakes Fault is located just south of Mt. Hood and is one of the southernmost faults in the Mt. Hood Fault Zone, previously mapped as approximately 12-13 km in length. This study provides the first in-depth characterization …

A Study On Fuzzy Time-Series And Its Applications To Stock Price Forecasting, Takeshi Stormer

University Honors Theses

Fuzzy mathematics looks to incorporate the vagueness that exists within the real world, specifically regarding imprecise classes, or non-numerical information expressed as "linguistic" variables. Since most traditional mathematical theories do not have the ability to be applied with the exactness that is otherwise seen in mathematics. As such, there had been many applications of fuzzy mathematics throughout many different fields of mathematics, including that of forecasting. By exploring the fundamentals of fuzzy mathematics, including fuzzy sets, operations of fuzzy sets, the surface level introduction to fuzzy logic, fuzzy relations, operations of fuzzy relations, and fuzzy time-series, this work looks to …

A Veblenian Approach To Chaos Theory, Isaiah Henry

Hatfield Graduate Journal of Public Affairs

This paper provides a comparative analysis of Veblen's belief in disequilibrium, the field of chaos theory, and how these two frameworks connect. We explore the similarities and differences between Veblen's theories and the principles of chaos theory, including their shared emphasis on complexity and unpredictability. By analyzing the connections between Veblen's economic theories and chaos theory, we can gain a deeper understanding of the nature of disequilibrium and the complex forces that shape our world.

Cannabis Concentrate Vaping Chemistry, Kaelas R. Munger, Killian M. Anreise, Robert M. Strongin

Chemistry Faculty Publications and Presentations

Background:

This review article addresses the vaping chemistry of manufactured cannabis concentrates—a topic that remains under-researched despite the widespread availability and growing popularity of these products. Given their current prevalence and the fact that many of the findings discussed herein are from early-stage investigations, further research is essential to fully assess the public health risks associated with concentrate use. The purpose of this article is to help begin to bridge this knowledge gap by outlining the technical challenges of studying cannabis concentrates and to present evidence-based data concerning toxicant exposures as a foundation for future investigations.

Methods:

A search of …

Temporal Modeling And Forecasting Of Blood Glucose Dynamics In Individuals With Diabetes Mellitus, Mj Ruff

University Honors Theses

People living with Diabetes Mellitus face significant health risks, including an increased likelihood of heart disease, stroke, and fluctuations in blood glucose levels. The unpredictable nature of glucose levels can lead to dangerous conditions such as ketoacidosis and hypoglycemia. This study employs advanced time series analysis tools to forecast the glucose levels for an individual diagnosed with Type 1 Diabetes Mellitus.

Teaching Diffuse, Specular, And Total Internal Reflection Via A Halo Effect, Paul R. Destefano, Ralf Widenhorn

Physics Faculty Publications and Presentations

Interesting and pedagogically useful physics can be found in the halo produced by a laser pointer directed into a shallow body of water. We describe a simple model for this phenomenon using geometric optics and support this model with empirical evidence. We also discuss and verify extensions to this model that explain variations in the visual pattern. These variants include a double halo pattern and a disk of dim light that can be produced with minor modifications of the single halo configuration. Although the level of complexity differs, all of these models rely on the same ray optics, specifically refraction …

Forecasting Influenza Rates Using Machine Learning: A Study Of Chatgpt's Predictive Accuracy, Sara Saleh

University Honors Theses

This study evaluates ChatGPT's ability to forecast influenza rates, such as the number of flu cases, hospitalizations, and death during peak season periods using CDC data, and comparing forecasts against actual results to calculate statistical accuracy and consistency. Influenza forecasting is essential for public health planning, but traditional methods may not always provide timely or accurate predictions. In this research study, ChatGPT was utilized to predict the influenza rates for the following week based on the previous week's data obtained from the FluView surveillance system. The predicted rates were compared to the actual influenza rates to assess the model's overall …

Investigation Into Thermodynamic And Kinetic Phenomena In Arylation Reactions With Diaryliodonium Salts, Soocheta Jha

Dissertations and Theses

Benzenoid rings are fundamental structural motifs in organic chemistry, widely recognized for their prevalence in natural products, pharmaceuticals, agrochemicals, and functional materials. Transition metal-catalyzed arylation, using catalysts such as palladium, nickel, or copper, has revolutionized C-C, C-O, and C-N bond formation, offering broad substrate scope and high efficiency. Among the reagents developed for efficient aryl group transfer, diaryliodonium salts have emerged as particularly powerful tools. Diaryliodonium salts facilitate metal-free arylations across a broad spectrum of nucleophiles, offering high reactivity, operational simplicity and environmental compatibility. The versatility of diaryliodonium salts has led to their widespread adoption as efficient arylating reagent in …

Short Communication: Multiscale Topographic Complexity Analysis With Pytopocomplexity, L. S.-H. Lai, Adam Booth, A. R. Duvall, E. Herzig

Geology Faculty Publications and Presentations

TopoComplexity is a Python package designed for efficient and customizable quantification of topographic complexity using four advanced methods: two-dimensional continuous wavelet transform analysis, fractal dimension estimation, rugosity index, and terrain position index calculations. This package addresses the lack of open-source software for these advanced terrain analysis techniques essential for modern geomorphology and geohazard research, enhancing data comparison and reproducibility. By assessing topographic complexity across multiple spatial scales, pyTopoComplexity allows users to identify characteristic morphological scales of studied landforms. The software repository also includes a Jupyter Notebook that integrates components from the surface-process modeling platform Landlab (Hobley et al., 2017), facilitating …

Poa Annua Ecology, Biology, And Integrated Weed Management Practices In Turfgrass, David Ervin

Environmental Science and Management Faculty Publications and Presentations

Poa annua L. is one of the most widespread and troublesome weeds of turfgrass. It persists as both an annual and perennial and is adaptable to almost any static maintenance regime, including adaptation to mowing heights and evolution of herbicide resistance. This management guide is intended to provide stakeholders with a summary of new and existing knowledge on integrated Poa annua management. Here we review the basic biology and ecology, as well as practical integrated weed management (IWM) strategies developed for its control.

Surface Temperature Analysis Report: Kellogg Creek Restoration & Community Enhancement Project, Dalton Palin

University Honors Theses

Kellogg Creek is located in the Kellogg-Mt Scott watershed which flows through downtown Milwaukie, Oregon into the Willamette River. At the confluence of Kellogg Creek and the Willamette River is the Kellogg Dam. This dam impedes salmon, steelhead, and lamprey movement up Kellogg Creek, which is known historically as a salmon and steelhead rearing and migrating habitat. A plan to remove Kellogg Dam and restore 14 acres of Kellogg Creek is in progress by North Clackamas Watersheds Council (NCWC) and partners. Water temperature studies in Kellogg Creek have been conducted for the past several years, this report analyzed thermal surface …

An Exposition Of "Probabilistic Polynomials And Hamming Nearest Neighbors", Vivek Srirama

University Honors Theses

This paper is an exposition of the paper Probabilistic Polynomials and Hamming Nearest Neighbors by Josh Alman and Ryan Williams. It presents the findings of this paper in a more accessible format for Computer Science students earlier in their career who may not be as familiar with Computational Theory and its concepts as their PhD counterparts are. The paper assumes that the reader has a basic understanding of Algorithms and Complexity, typically obtained in an introductory level Algorithms course.

The paper by Alman and Williams analyzes a specific problem known as the Hamming Nearest Neighbor problem. All known solutions for …

Raising The Roof For All: Integrating Companion Planting Ecology, Policy And Community In Portland's Green Roof Future, Zoe Edelman

University Honors Theses

Green roofs, or ecoroofs, provide environmental and social benefits in urban areas. Ecoroofs manage stormwater by absorbing rainfall, reducing rooftop temperatures, supporting pollinators, and offering green space in densely developed cities. Portland, Oregon has adopted progressive policies that encourage green roof installation through incentives and building requirements. However, many ecoroofs in the city are underperforming due to poor maintenance, low public awareness, and limited access to rooftop spaces. This thesis explores whether companion planting can improve the ecological performance and long- term viability of extensive green roofs. A rooftop experiment at Portland State University tested the growth of radishes, with …

Rebuilding Consent: Fear, Trust, And The Future Of Nuclear Energy, Austin Dunham

University Honors Theses

This thesis traces the cultural and emotional roots of nuclear fear in the United States and explores how those inherited anxieties continue to shape public resistance to nuclear energy in the face of a worsening climate crisis. Drawing on personal narrative, risk perception theory, and the history of nuclear discourse - from Hiroshima to Chernobyl to today - the research examines how trust, rather than technology, remains the largest barrier to progress. By analyzing the stories we tell about energy, disaster, control, and overall perceived risk, this work asks what it would take for Americans to imagine nuclear energy not …

Early-Stage Detection Of Copper Ion Release From Bronze Corrosion Using Uv/Vis Spectroscopy And Hydrogel Sensing, Hibah Khan

University Honors Theses

Detecting copper(I) (Cu⁺) release at early corrosion stages is important for preserving bronze heritage materials. This study investigated the use of neocuproine (NC), a Cu⁺-specific ligand, for simple and selective colorimetric detection of Cu⁺ in solution. NC reacts with Cu⁺ to form a Cu(NC)₂ complex, which produces a distinct orange-red color with peak absorbance at 455 nm. Solutions were prepared with varying concentrations of Cu⁺ generated by reducing Cu²⁺ with excess ascorbic acid. Ultraviolet/Visible (UV/Vis) spectroscopy was used to quantify absorbance changes. The absorbance at 455 nm increased linearly across the tested Cu⁺ concentration range (6.25–200 µM) with an R² …

Indigenous Science And The Legacy Of Fire: Resilience, Fuels, Mosaics, And Eco-Cultural Landscapes In Oregon’S Coastal And Cascade Range, Julia Alcalá

University Honors Theses

Most of Oregon's western Cascade and Coastal range is a landscape that has historically been considered devoid of mid to low-intensity fires by Western science. However, for time immemorial, Indigenous peoples have been stewarding the forests through the use of "good fire," creating diverse and heterogenous landscapes with mixed fire regimes, ranging from less than a decade to several centuries since the last fire, resulting in a mosaic of patchy forest, oak savannas, prairies, and wetlands. Yet centuries of Indigenous displacement, cultural assimilation, and suppression of cultural burning contributed to this prevailing belief. Despite that, in recent decades, Western scientists …

Advanced Machine Learning Techniques For Social Support Detection On Social Media, Olga Kolesnikova, Moein Shahiki Tash, Zahra Ahani, Ameeta Agrawal, Raúl Monroy, Grigori Sidorov

Computer Science Faculty Publications and Presentations

The widespread use of social media highlights the need to understand its impact, particularly the role of online social support. In this study, we present a dataset of YouTube comments, initially comprising 66,272 entries, which was refined to 42,695, with a subset of 10,000 comments selected for detailed analysis without additional filtering. The dataset is annotated for three classification tasks: (1) distinguishing supportive from non-supportive comments, (2) determining whether the support is directed at an individual or a group, and (3) further categorizing group support into six subtypes (Nation, LGBTQ, Black Community, Women, Religion, and Other). To address data imbalances …

Identifying Antimalarials That Disrupt Malaria Parasite Transmission When Fed To The Mosquito, Sarah N. Farrell, Anton Cozijnsen, Vanessa Mollard, Papireddy Kancharla, Rozalia A. Dodean, Jane X. Kelly, Geoffrey I. Mcfadden, Christopher D. Goodman

Chemistry Faculty Publications and Presentations

A decade-long decline in malaria cases has plateaued, primarily due to parasite drug resistance and mosquito resistance to insecticides used in bed nets and indoor residual spraying. Here, we explore the innovative control strategy targeting Plasmodium with antimalarials during the mosquito stages. This strategy has the potential to reduce the risk of resistance emerging because a relatively small population of parasites within the mosquito is subject to selection. After validating mosquito feeding strategies, we screened a range of parasiticidal compounds by feeding them to mosquitoes already infected with mouse malaria (P. berghei). Three antimalarials showed activity against P. berghei in …

Helmholtz Cage: Software Development And Implementation For Cubesat Testing, Gustavo A. Cotom Lopez

University Honors Theses

This paper details the successful development and deployment of a Helmholtz cage system, designed to produce precisely controlled magnetic fields for testing and calibration purposes. The core focus was on creating a robust, modular software architecture enabling independent current modulation on each axis, comprehensive serial communication between multiple microcontrollers, and real-time data acquisition from the MR3 magnetometer. All software components, including the serial communication drivers, control algorithms, command line interface, and calibration routines, were developed from the ground up. The system was fully operational upon completion: all hardware components functioned as intended, serial communication with each subsystem was reliable, and …

Book Review Of, Participatory Engineering Of Algorithmic Socialtechnologies: An Extended Book Review Of David G. Robinson's Voices Inthe Code, Rajesh Venkatachalapathy

Complex Systems Faculty Publications and Presentations

David G. Robinson’s Voices in the Code, reviewed here, approaches the issue of governance and regulation of algorithmic social technologies with a case study orientation that offers a grounding in the details, illuminating the fundamentally sociological and processual nature of modern governance issues that are mostly missed or left implicit in academic, regulatory, and legislative discussions. This important book urges us to design adaptive, malleable, and evolvable participatory organizational structures instead. Accepting the author’s invitation to carry the torch forward, this review builds on and extends the book’s arguments by presenting broad and transferable insights on regulation and governance …