Physical Sciences and Mathematics Commons^™

A Simpler Machine Learning Model For Acute Kidney Injury Risk Stratification In Hospitalized Patients, Yirui Hu, Kunpeng Liu, Kevin Ho, David Riviello, Jason Brown, Alex R. Chang, Gurmukteshwar Singh, H. Lester Kirchner

Computer Science Faculty Publications and Presentations

Background: Hospitalization-associated acute kidney injury (AKI), affecting one-in-five inpatients, is associated with increased mortality and major adverse cardiac/kidney endpoints. Early AKI risk stratification may enable closer monitoring and prevention. Given the complexity and resource utilization of existing machine learning models, we aimed to develop a simpler prediction model. Methods: Models were trained and validated to predict risk of AKI using electronic health record (EHR) data available at 24 h of inpatient admission. Input variables included demographics, laboratory values, medications, and comorbidities. Missing values were imputed using multiple imputation by chained equations. Results: 26,410 of 209,300 (12.6%) inpatients developed AKI during …

Chemical Interactions And Cytotoxicity Of Terpene And Diluent Vaping Ingredients, Yanira Baldovinos, Alexandra Archer, James C. Salamanca, Robert M. Strongin, Christie Sayes

Chemistry Faculty Publications and Presentations

Vaping devices have risen in popularity since their inception in 2007. The practice involves using a variety of commercially available devices. Internal heating systems in devices aerosolize e-liquid formulations of complex mixtures including an active ingredient (e.g., THC, CBD, and nicotine), diluents (or cutting agents), solvents, and flavoring agents (e.g., terpenes and aldehydes). The vaping toxicology literature consists of cytotoxicity studies of individual chemicals and commercial formulas. Because of the variation of e-liquid composition, there is a limited understanding of the toxicity of ingredient combinations. This study analyzed the cytotoxic effects after exposure to individual and binary mixtures of a …

Computational Investigation Into Heteroleptic Photoredox Catalysts Based On Nickel(Ii) Tris-Pyridinethiolate For Water Splitting Reactions, Avik Bhattacharjee, Dayalis S.V. Brown, Trent E. Ethridge, Kristine M. Halvorsen, Alejandra C. Acevedo Montano, Theresa M. Mccormick

Chemistry Faculty Publications and Presentations

This work demonstrates a strategy to fine-tune the efficiency of a photoredox water splitting Ni(II) tris-pyridinethiolate catalyst through heteroleptic ligand design using computational investigation of the catalytic mechanism. Density functional theory (DFT) calculations, supported by topology analyses using quantum theory of atoms in molecules (QTAIM), show that the introduction of electron donating (ED) −CH3 and electron withdrawing (EW) −CF₃ groups on the thiopyridyl (PyS–) ligands of the same complex can tune the pK_a and E0, simultaneously. Computational modeling of two heteroleptic nickel(II) tris-pyridinethiolate complexes with 2:1 and 1:2 ED and EW −CH₃ and −CF_{3 …}

Cascadia Subduction Zone Earthquake Vertical Ground Acceleration Investigation And Potential Impact On Bridges In The Pacific Northwest, Rachel Caroline Bassil

Civil and Environmental Engineering Master's Project Reports

The effects of vertical ground accelerations during subduction zone earthquakes currently are not sufficiently understood. There are numerous case studies and evidence that effects of vertical ground accelerations can significantly impact the performance of bridges during a seismic event, but most previous research has been focused on shallow crustal earthquakes. Current bridge design codes provide little guidance for accounting for vertical ground accelerations in seismic design, in part because additional information is needed about the characteristics of vertical ground motions during Cascadia Subduction Zone (CSZ) earthquakes in the Pacific Northwest.

For this study, recorded seismic data from recent subduction zone …

Transient Vision Loss Associated With Prefilled Aflibercept Syringes: A Case Series And Analysis Of Injection Force, Daniel J. Lee, Brittni A. Scruggs, Erik J. Sánchez, Merina Thomas, Ambar Faridi

Physics Faculty Publications and Presentations

Purpose

To describe cases of significant vision loss after intravitreal aflibercept administration using prefilled syringes (PFS) and to study the relationships among syringe design, injection speed, and injection force.

Design

Retrospective case series and experimental study.

Participants

Twelve patients who received intravitreal aflibercept via PFS.

Methods

All retina specialists (n = 13) at Oregon Health & Science University and the Veterans Affairs Portland Medical Center were queried in December 2020 to report episodes of significant vision loss after aflibercept PFS use. Chart review was completed for all affected patients. Using a commercially available force measuring system, injection force was measured …

Biogeochemical Responses To Mixing Of Glacial Meltwater And Hot Spring Discharge In The Mount St. Helens Crater, Ashley Dubnick, Q. Faber, J. R. Hawkings, N. Bramall, B. C. Christner, Peter T. Doran, Jay Nadeau, C. Snyder, Multiple Additional Authors

Physics Faculty Publications and Presentations

Environments where geothermal waters and glacier meltwater mix are common on Earth yet little is known about the biogeochemical processes that occur when hot, reduced geothermal water mixes with cold, oxidized glacial meltwater in natural systems. Mount St. Helens provides an ideal location to study the interaction between geothermal and glacier waters since the water sources, and their mixing environment in Step Creek, are exposed in the volcanic crater. We find that the two water sources contain distinct major ion, trace element, dissolved organic matter (DOM), and biological signatures. The hot spring contains high concentrations of biogeochemically reactive components (e.g., …

Short Warm-Side Wet-Bulb Temperature Distribution Tails Lead To Accelerated Increases In Extreme Threshold Exceedances Under Global Warming, Yianna Sotirios Bekris

Dissertations and Theses

Humid-heat extremes threaten human health and are increasing in frequency with global warming, so elucidating factors affecting their rate of change is critical. This thesis examines the role of historical (1985-2014) wet-bulb temperature distribution tail shape on the probability of wet-bulb temperature extreme threshold exceedances under 2°Celsius global warming. Analysis of global climate models and reanalysis reveals that non-Gaussian wet-bulb temperature distribution tails are common worldwide across extensive, spatially coherent regions. More rapid increases in the number of days exceeding the historical 95th percentile are projected in locations with shorter-than-Gaussian warm-side tails. Of the two primary components of wet-bulb temperature, …

Topological Anomaly Detection In Dynamic Multilayer Blockchain Networks, Dorcas Ofori-Boateng, I. Segovia Dominguez, C. Akcora, M. Kantarcioglu, Y. R. Gel

Mathematics and Statistics Faculty Publications and Presentations

Motivated by the recent surge of criminal activities with cross-cryptocurrency trades, we introduce a new topological perspective to structural anomaly detection in dynamic multilayer networks. We postulate that anomalies in the underlying blockchain transaction graph that are composed of multiple layers are likely to also be manifested in anomalous patterns of the network shape properties. As such, we invoke the machinery of clique persistent homology on graphs to systematically and efficiently track evolution of the network shape and, as a result, to detect changes in the underlying network topology and geometry. We develop a new persistence summary for multilayer networks, …

Warming Of The Willamette River, 1850–Present: The Effects Of Climate Change And Direct Human Interventions, Stefan Talke, David Jay, Heida Diefenderfer

Civil and Environmental Engineering Faculty Publications and Presentations

Using archival research methods, we found and combined data from multiple sources to produce a unique, 140 year record of daily water temperature (Tw) in the lower Willamette River, Oregon (1881–1890, 1941–present). Additional daily weather and river flow records from the 1850s onwards are used to develop and validate a statistical regression model of Tw for 1850–2020. The model simulates the time-lagged response of Tw to air temperature and river flow, and is calibrated for three distinct time periods: the late 19th, mid 20th, and early 21st centuries. Results show that Tw has trended upwards at ~1.1 °C …

Introduction To Mathematical Analysis I - 3rd Edition, Beatriz Lafferriere, Gerardo Lafferriere, Mau Nam Nguyen

PDXOpen: Open Educational Resources

Video lectures explaining problem solving strategies are available.

This set of lecture notes is meant to provide students with a strong foundation in mathematical analysis. Such a foundation is crucial for future study of deeper topics of analysis. Students should be familiar with most of the concepts presented here after completing the calculus sequence. However, these concepts will be reinforced through rigorous proofs.

Introduction to Mathematical Analysis II contains lecture notes that complement this book, 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 …

Ecological Homogenization Of Oil Properties In The American Residential Macrosystem, Christopher D. Ryan, Peter M. Groffman, J. Morgan Grove, Sharon J. Hall, James B. Heffernan, Sarah E. Hobbie, Dexter H. Locke, Jennifer L. Morse, Rinku Roy Chowdhury, Tara Trammell, Multiple Additional Authors

Environmental Science and Management Faculty Publications and Presentations

The conversion of native ecosystems to residential ecosystems dominated by lawns has been a prevailing land-use change in the United States over the past 70 years. Similar development patterns and management of residential ecosystems cause many characteristics of residential ecosystems to be more similar to each other across broad continental gradients than that of former native ecosystems. For instance, similar lawn management by irrigation and fertilizer applications has the potential to influence soil carbon (C) and nitrogen (N) pools and processes. We evaluated the mean and variability of total soil C and N stocks, potential net N mineralization and nitrification, …

Predicting Springtime Herbicide Exposure Across Multiple Scales In Pacific Coastal Drainages (Oregon, Usa), Kaegan Michael Scully-Engelmeyer, Elise F. Granek

Environmental Science and Management Faculty Publications and Presentations

Identification of non-point sources of watershed pollution such as pesticide runoff is challenging due to spatial and temporal variation in landscape patterns of land use and environmental conditions. Regional case study monitoring investigations can document region-specific conditions and processes to inform managers about pesticide movement through watersheds. Additionally, modeling field-collected data within these contexts can be used to predict pesticide presence in un-sampled areas. During a 45 day period in the spring of 2019, we sampled sixteen coastal watersheds in Oregon, USA for current-use water-borne herbicides commonly used in forestland vegetation management. At 80 % of sampling locations, at least …

Motion-Adjustable Neural Implicit Video Representation, Long Mai, Feng Liu

Computer Science Faculty Publications and Presentations

Implicit neural representation (INR) has been successful in representing static images. Contemporary image-based INR, with the use of Fourier-based positional encoding, can be viewed as a mapping from sinusoidal patterns with different frequencies to image content. Inspired by that view, we hypothesize that it is possible to generate temporally varying content with a single image-based INR model by displacing its input sinusoidal patterns over time. By exploiting the relation between the phase information in sinusoidal functions and their displacements, we incorporate into the conventional image-based INR model a phase-varying positional encoding module, and couple it with a phase-shift generation module …

System Design For The Quantification Of Microbial Motility In Extreme Environments, Megan Marie Dubay

Dissertations and Theses

Motility of microorganisms is understudied but provides useful insights into their behavior. Organisms' ability to move autonomously changes how they interact with their environment--finding nutrients, interacting with other organisms, and avoiding unfavorable conditions. Understanding motility features can also be used to identify specific species, such as the identification of Vibrio cholerae in human samples. Motility might also be used as evidence of life existing in even the most extreme environments on Earth, and possibly beyond. Specialized microscopy systems can be required to examine the motility of microorganisms due to the nature of the environments to which the instruments are exposed. …

Proceedings Of The Rust-Edu Workshop, Bart Massey

Rust-Edu Workshop

The 2022 Rust-Edu Workshop was an experiment. We wanted to gather together as many thought leaders we could attract in the area of Rust education, with an emphasis on academic-facing ideas. We hoped that productive discussions and future collaborations would result. Given the quick preparation and the difficulties of an international remote event, I am very happy to report a grand success. We had more than 27 participants from timezones around the globe. We had eight talks, four refereed papers and statements from 15 participants. Everyone seemed to have a good time, and I can say that I learned a …

Forest Fire Effects On Landscape Snow Albedo Recovery And Decay, Max Gersh, Kelly E. Gleason, Anton Surunis

Environmental Science and Management Faculty Publications and Presentations

Surface snow albedo (SSA) darkens immediately following a forest fire, while landscape snow albedo (LSA) brightens as more of the snow-covered surface becomes visible under the charred canopy. The duration and variability of the post-fire snow albedo recovery process remain unknown beyond a few years following the fire. We evaluated the temporal variability of post-fire snow albedo recovery relative to burn severity across a chronosequence of eight burned forests burned from 2000 to 2019, using pre- and post-fire daily, seasonal, and annual landscape snow albedo data derived from the Moderate Resolution Imaging Spectroradiometer (MOD10A1). Post-fire annual LSA increased by 21% …

Spatial Analysis Of Burn Severity And Streamflow Response In The Western Conus, Will Brendan Long

Dissertations and Theses

Wildfire increases the magnitude of runoff in catchments, which can lead to the degradation of ecosystems, risk to infrastructure, and loss of life. The Labor Day Fires of 2020 provided an opportunity to compare multiple large and severe wildfires with the objective of determining potential changes to hydrologic processes in Oregon Cascades watersheds. Geographic information systems (GIS) were implemented to determine the total percentage burned and percentage of high burn severity class of six watersheds on the west-slope of the Oregon Cascade Range. In addition, two control watersheds were included to contrast the influence of climatic effects. Spatial arrangement of …

Investigation Of Basal Imnaha Basalt Flows And Their Relationship To The Picture Gorge Basalt Of The Columbia River Basalt Group, Luke James Fredenberg

Dissertations and Theses

The lower American Bar flows (AB 1 and 2) of the Imnaha Basalt have previously been observed as being chemically similar to those of the Picture Gorge Basalt (PGB). Previous age data separate eruption of the Imnaha and Picture Gorge Basalts by approximately 1.5 Ma, precluding the possibility of a genetic link between the two basalt units. New age data for the Picture Gorge Basalt has expanded the eruptive timeframe and the earliest flows coincide with the eruption of the Imnaha Basalt, making it possible that the lower American Bar flows of the Imnaha Basalt and the Picture Gorge Basalt …

System Dynamics Modeling For Traumatic Brain Injury: Mini-Review Of Applications, Erin S. Kenzie, Elle L. Parks, Nancy Carney, Wayne Wakeland

Complex Systems Faculty Publications and Presentations

Traumatic brain injury (TBI) is a highly complex phenomenon involving a cascade of disruptions across biomechanical, neurochemical, neurological, cognitive, emotional, and social systems. Researchers and clinicians urgently need a rigorous conceptualization of brain injury that encompasses nonlinear and mutually causal relations among the factors involved, as well as sources of individual variation in recovery trajectories. System dynamics, an approach from systems science, has been used for decades in fields such as management and ecology to model nonlinear feedback dynamics in complex systems. In this mini-review, we summarize some recent uses of this approach to better understand acute injury mechanisms, recovery …

Characterizing The Single-Photon State: Quantum Physics Experiments With Single-Photon Sensitivity, Sheldon Lee Field

University Honors Theses

Coincidence-counting and spontaneous parametric downconversion are central to introductory quantum mechanical experimentation but have remained largely out of reach of undergraduate physics instructors. This thesis summarizes the theory behind light polarization, spontaneous parametric downconversion, birefringent refractive indices, and an affordable self-contained photon coincidence counting unit (CCU). A method for implementing a CCU to demonstrate downconversion is presented, and empirical results are provided.

Post-Fire Erosional And Hydrological Processes Promoting Debris Flow Initiation In A Douglas Fir And Western Hemlock Forest In The Riverside Burn Area, Oregon, Morena Nicole Hammer

Dissertations and Theses

Post-fire debris flows initiated by overland flow in the Pacific Northwest (PNW) are largely undocumented. Instead, debris flows are typically initiated by shallow landslides that result in a mud slurry of water and sediments traveling downhill under the force of gravity. However, because of the Fall 2020 fires in Oregon, the typical initiation style and erosional patterns in burned catchments may have changed because of unusually high burn severity. Due to the intensity of these fires, we set out to determine how hydrologic processes and erosion occurred, when they occurred, and what process was primarily responsible for the erosion that …

On Capturing Human Agency And Methodological Interdisciplinarity In Socio-Hydrology Research, David J. Yu, Melissa Haeffner, Hanseok Jeong, Saket Pande, Juliane Dame, Giuliano Di Baldassarre, Glenda Garcia-Santos, Leon Hermans, Rashata Muneepeerakul, Multiple Additional Authors

Environmental Science and Management Faculty Publications and Presentations

Socio-hydrology has expanded and been effective in exposing the hydrological community to ideas and approaches from other scientific disciplines, and social sciences in particular. Yet it still has much to explore regarding how to capture human agency and how to combine different methods and disciplinary views from both the hydrological and the social sciences to develop knowledge. A useful starting ground is noting that the complexity of human–water relations is due to interactions not only across spatial and temporal scales but also across different organizational levels of social systems. This calls for consideration of another analytical scale, the human organizational …

Standardized Neon Organismal Data For Biodiversity Research, Daijiang Li, Sydne Record, Eric R. Sokol, Matthew E. Bitters, Melissa Y. Chen, Ruvi Jaimes, Matthew R. Helmus, Lara Jansen, Marta A. Jarzyna, Multiple Additional Authors

Environmental Science and Management Faculty Publications and Presentations

Understanding patterns and drivers of species distribution and abundance, and thus biodiversity, is a core goal of ecology. Despite advances in recent decades, research into these patterns and processes is currently limited by a lack of standardized, high-quality, empirical data that span large spatial scales and long time periods. The NEON fills this gap by providing freely available observational data that are generated during robust and consistent organismal sampling of several sentinel taxonomic groups within 81 sites distributed across the United States and will be collected for at least 30 years. The breadth and scope of these data provide a …

Quantum Algorithms For Attacking Hardness Assumptions In Classical And Post‐Quantum Cryptography, J.-F. Biasse, X. Bonnetain, E. Kirshanova, A. Schrottenloher, Fang Song

Computer Science Faculty Publications and Presentations

In this survey, the authors review the main quantum algorithms for solving the computational problems that serve as hardness assumptions for cryptosystem. To this end, the authors consider both the currently most widely used classically secure cryptosystems, and the most promising candidates for post-quantum secure cryptosystems. The authors provide details on the cost of the quantum algorithms presented in this survey. The authors furthermore discuss ongoing research directions that can impact quantum cryptanalysis in the future.

Understanding Water Security In Portland, Oregon: Using Newspapers As Tools For Science Communication And Education, Julian Roth

University Honors Theses

Water insecurity is faced by a large percentage of the global population, particularly in urban areas, which face greater and more complex needs for water resources. Better tools are needed to be able to recognize and communicate water security issues in a way that reinforces water systems, engages all stakeholders, and recognizes early warnings of environmental injustice. This research examines utilizing public newspaper articles to produce these tools. Using a case-study approach, this thesis explores newspaper articles about water from 2014-2020 in the urban center of Portland, Oregon, to understand local water security issues and to build a system of …

An Economical And Repeatable Method For Mapping Shade Cast On Water Channels, Eric M. Nielsen

Institute for Natural Resources Publications

The motivation of this work is to provide insights toward determining a viable strategy for statewide monitoring of riparian vegetation condition, with particular focus on developing a repeatable, costeffective method for assessment of progress toward achieving temperature-based water quality standards mandated by the federal Clean Water Act. A reliable monitoring strategy could in turn support a datadriven prioritization and assessment framework to increase the efficiency, effectiveness and accountability of riparian restoration efforts. In this project we developed and tested a method for mapping shade cast on water channels by riparian vegetation using optical imagery sources that are affordable and regularly …

Equilibria: Sustainability And Eco-Awareness In Music Production, Ashley A. Kahl-Placek

University Honors Theses

Cross-disciplinary exploration between science and the arts is one tool to help solve some of the biggest issues facing humans. Climate change and loss of biodiversity can be represented via sound art and contemporary music composition. Wholistic eco-awareness and sustainability are possible when projects are based in unique species-inspired soundscapes, the cultivation of targeted, action-inspiring lyricism, and a sustainable navigation of the marketing and distribution pathways of the music industry. From the fall of 2021 to summer of 2022, field recordings of unique ecosystems were collected and combined with songwriting rooted in a love and hope for the future of …

Multi-Method Investigation Of Factors Influencing Amyloid Onset And Impairment In Three Cohorts, Tobey J. Betthauser, Murat Bilgel, Rebecca L. Koscik, Bruno Jedynak, Yang An, Kristina A. Kellett, Abhay Moghekar, Erin M. Jonaitis, Charles K. Stone, Multiple Additional Authors

Mathematics and Statistics Faculty Publications and Presentations

Alzheimer’s disease biomarkers are becoming increasingly important for characterizing the longitudinal course of disease, predicting the timing of clinical and cognitive symptoms, and for recruitment and treatment monitoring in clinical trials. In this work, we develop and evaluate three methods for modelling the longitudinal course of amyloid accumulation in three cohorts using amyloid PET imaging. We then use these novel approaches to investigate factors that influence the timing of amyloid onset and the timing from amyloid onset to impairment onset in the Alzheimer’s disease continuum.

Data were acquired from the Alzheimer’s Disease Neuroimaging Initiative (ADNI), the Baltimore Longitudinal Study of …

An Integral Transform For Quantum Amplitudes, Jack C. Straton

Physics Faculty Publications and Presentations

The central impediment to reducing multidimensional integrals of transition amplitudes to analytic form, or at least to a fewer number of integral dimensions, is the presence of magnitudes of coordinate vector differences (square roots of polynomials) |x1−x2|2=x21−2x1x2cosθ+x2 √ in disjoint products of functions. Fourier transforms circumvent this by introducing a three-dimensional momentum integral for each of those products, followed in many cases by another set of integral transforms to move all of the resulting denominators into a single quadratic form in one denominator whose square my be completed. Gaussian transforms introduce a one-dimensional integral for each such product while squaring …

Orthotrichum Lyellii As An Active Moss Biomonitor: Examining The Interplay Between Ambient Pm10, Bulk Deposition And Heavy Metals In An Urban Environment, Scott Bradley Kiel

Dissertations and Theses

The importance of monitoring and preventing pollution in the environment is a globally recognized issue. Of the criteria pollutants outlined by the United States Environmental Protection Agency, particulate matter is among these least understood in relation to toxicity and most wide-spread. Many governments have employed continuous air quality monitoring networks to track ambient levels of particulate matter, but are often too widespread to capture the heterogeneity of the urban environment, especially for heavy metal deposition. In Portland, OR, the epiphytic moss Orthotrichum lyellii was successfully used as a low-cost passive biomonitor to increase the spatial resolution of pollution around the …