Physical Sciences and Mathematics Commons^™

Effects Of Spontaneous Curvature On Interfacial Adsorption And Collapse Of Phospholipid Monolayers, Bret A. Brandner, Shankar B. Rananavare, Stephen B. Hall

Chemistry Faculty Publications and Presentations

To function effectively, pulmonary surfactant must adsorb rapidly to the alveolar air/water interface but avoid collapse from the surface when compressed to high interfacial densities. Prior studies show that phospholipids in the cylindrical monolayers of the inverse hexagonal (HII) phase adsorb quickly. The monolayers have negative curvature, defined by the concave shape of the hydrophilic face. Formation of the HII structures, however, involves significant disruption of chain-packing. Samples with significant spontaneous curvature, formed in the absence of applied force, may nonetheless have lamellar structures that optimize chain-packing. The experiments here tested whether planar lamellar bilayers formed by phospholipids with negative …

Graph Regularized Sparse L2,1 Semi-Nonnegative Matrix Factorization For Data Reduction, Anthony Rhodes, Bin Jiang, Jenny Jiang

Mathematics and Statistics Faculty Publications and Presentations

Non-negative Matrix Factorization (NMF) is an effective algorithm for multivariate data analysis, including applications to feature selection, pattern recognition, and computer vision. Its variant, Semi-Nonnegative Matrix Factorization (SNF), extends the ability of NMF to render parts-based data representations to include mixed-sign data. Graph Regularized SNF builds upon this paradigm by adding a graph regularization term to preserve the local geometrical structure of the data space. Despite their successes, SNF-related algorithms to date still suffer from instability caused by the Frobenius norm due to the effects of outliers and noise. In this paper, we present a new L2,1 SNF algorithm that …

Causal Effect Estimation In Survival Analysis With High Dimensional Confounders, Fei Jiang, Ge Zhao, Rosa Rodriguez-Monguio, Yanyuan Ma

Mathematics and Statistics Faculty Publications and Presentations

With the ever advancing of modern technologies, it has become increasingly common that the number of collected confounders exceeds the number of subjects in a data set. However, matching based methods for estimating causal treatment effect in their original forms are not capable of handling high-dimensional confounders, and their various modified versions lack statistical support and valid inference tools. In this article, we propose a new approach for estimating causal treatment effect, defined as the difference of the restricted mean survival time (RMST) under different treatments in high-dimensional setting for survival data. We combine the factor model and the sufficient …

Re-Evaluating Hypertragulid Diversity In The John Day Basin, Oregon, Usa, Nicholas A. Famoso, Lana K. Jewell

Geology Faculty Publications and Presentations

Despite their relative abundance, members of the family Hypertragulidae (Artiodactyla, Mammalia) have proved a conundrum regarding species diversity in the Turtle Cove Member (Oligocene) of the John Day Formation, located in central and eastern Oregon. Three species and two separate genera are described in the area, but previous research lacks statistical support for this level of variation. We use coefficients of variation (V) on measurements of dentition and astragali of hypertragulid specimens designated Hypertragulus hesperius, Hypertragulus minutus, and Nanotragulus planiceps as a metric for determining whether there were multiple species present in the population. Asymptotic and modified signed-likelihood ratio V …

Oregon State Rank Assessment For Sheldon Tui Chub (Siphateles Bicolor Eurysoma), Eleanor P. Gaines

Institute for Natural Resources Publications

Oregon state conservation status assessment for Sheldon tui chub (Siphateles bicolor eurysoma) using NatureServe methodology, 2024.

Stability Analysis For Acoustic Waveguides. Part 3: Impedance Boundary Conditions, Leszek Demkowicz, Jay Gopalakrishnan, Norbert Heuer

Mathematics and Statistics Faculty Publications and Presentations

A model two-dimensional acoustic waveguide with lateral impedance boundary conditions (and outgoing boundary conditions at the waveguide outlet) is considered. The governing operator is proved to be bounded below with a stability constant inversely proportional to the length of the waveguide. The presence of impedance boundary conditions leads to a non self-adjoint operator which considerably complicates the analysis. The goal of this paper is to elucidate these complications and tools that are applicable, as simply as possible. This work is a continuation of prior waveguide studies (where self-adjoint operators arose) by J. M. Melenk et al. (2023), and L. Demkowicz …

Oregon State Rank Assessment For Goose Lake Tui Chub (Siphateles Bicolor Thalassinus), Jesse Laney

Institute for Natural Resources Publications

Oregon state conservation status assessment for Goose Lake tui chub (Siphateles bicolor thalassinus) using NatureServe methodology, 2024.

Projected Loss Of Rock Glacier Habitat In The Contiguous Western United States With Warming, Abigail C. Lute, John T. Abatzoglou, Andrew G. Fountain, Timothy C. Bartholomaus

Geology Faculty Publications and Presentations

Rock glaciers support alpine biodiversity and may respond more slowly to warming than snow or glaciers. While responses of snow and glaciers to climate change are relatively well understood, a robust assessment of rock glacier environmental niche, future distributions of rock glaciers and potential for development of rock glaciers from current glaciers is lacking. Using process-relevant, high-resolution environmental descriptors, we develop a species distribution model of the topographic, geologic and hydroclimatic niche of rock glaciers that provides novel estimates of potential rock glacier distributions for different climates. We identify mean annual air temperature and headwall area as the dominant controls …

On Localization Of Eigenfunctions Of The Magnetic Laplacian, Jeffrey S. Ovall, Hadrian Quan, Robyn Reid, Stefan Steinerberger

Mathematics and Statistics Faculty Publications and Presentations

Let Ω ⊂ ℝd and consider the magnetic Laplace operator given by H(A) = (–i∇ – A(x))2, where A : Ω → ℝd, subject to Dirichlet boundary conditions. For certain vector fields A, this operator can have eigenfunctions, H(A)ψ = λψ, that are highly localized in a small region of Ω. The main goal of this paper is to show that if |ψ| assumes its maximum at x0 ∈ Ω, then A behaves 'almost' like a conservative vector field in a -neighborhood of x0 in a precise sense. In particular, we expect localization in regions where |curl A| is small. …

Tabular Data-Centric Ai: Challenges, Techniques And Future Perspectives, Yanjie Fu, Dongjie Wang, Hui Xiong, Kunpeng Liu

Computer Science Faculty Publications and Presentations

Tabular data are the most widely used data formats in almost every application domain, such as, biology, ecology, and material science. The purpose of tabular data-centric AI is to use AI to augment the predictive power of tabular data to get better AI. Tabular data-centric AI is essential because it can reconstruct distance measures, reshape discriminative patterns, and improve data AI readiness (structural, predictive, interaction, and expression levels), which is significant in industries and real-world deployments. Therefore, our tutorial is designed to capture the interest of professionals with expertise in artificial intelligence, machine learning, and data mining, as well as …

A Coupled Spatial-Network Model: A Mathematical Framework For Applications In Epidemiology, Hannah Kravitz, Christina Duron, Moysey Brio

Mathematics and Statistics Faculty Publications and Presentations

There is extensive evidence that network structure (e.g., air transport, rivers, or roads) may significantly enhance the spread of epidemics into the surrounding geographical area. A new compartmental modeling framework is proposed which couples well-mixed (ODE in time) population centers at the vertices, 1D travel routes on the graph’s edges, and a 2D continuum containing the rest of the population to simulate how an infection spreads through a population. The edge equations are coupled to the vertex ODEs through junction conditions, while the domain equations are coupled to the edges through boundary conditions. A numerical method based on spatial finite …

Information-Theoretic Modeling Of Categorical Spatiotemporal Gis Data, David Percy, Martin Zwick

Geology Faculty Publications and Presentations

An information-theoretic data mining method is employed to analyze categorical spatiotemporal Geographic Information System land use data. Reconstructability Analysis (RA) is a maximum-entropy-based data modeling methodology that works exclusively with discrete data such as those in the National Land Cover Database (NLCD). The NLCD is organized into a spatial (raster) grid and data are available in a consistent format for every five years from 2001 to 2021. An NLCD tool reports how much change occurred for each category of land use; for the study area examined, the most dynamic class is Evergreen Forest (EFO), so the presence or absence of …

Minimal Separating Sets In Surfaces, Christopher Nelson Aagaard

Dissertations and Theses

Given a connected topolgical space X, we say that L ⊆ X is a minimal separating set if removing L from X gives a disconnected surface, butremoving any proper subset of L leaves the surface connected. We classify which embeddings of topological graphs are minimal separating in an orientable surface X with genus g, and construct a computer program to compute the number of such embeddings, and the number of topological graphs which admit such an embedding for g ≤ 5.

The Foodpunk City: Advancing Portland's Food Security Through A Shared Ideology Of Adaptation & Resistance, Nickolas Hash

Dissertations and Theses

Food injustice is a form of violence perpetrated by state and corporate actors against a constituency under their governing power, particularly impacting marginalized and impoverished communities. It denies individuals access to nutritious food, perpetuating cycles of poverty, inequality, physical health risks, and social exclusion. Grassroots movements have emerged to challenge dominant paradigms and advocate for food sovereignty, agroecology, and food anarchy. In Portland, the movement represents a nontraditional approach to food security that closely resembles the reactionary ideology of urban "punk" culture. Both groups prioritize community autonomy over food systems, sustainable agricultural practices, and resistance to oppressive structures that perpetuate …

Introduction To The Virtual Special Issue: Mathematics That Underpins Social Issues, Eva Thanheiser, Ami Mamolo

Mathematics and Statistics Faculty Publications and Presentations

This Virtual Special Issue on Mathematics in Society: Exploring the Mathematics that Underpins Social Issues features 13 articles which expand our understanding of how people build, retain, communicate, apply, and comprehend mathematical ideas as they relate to social and societal issues. The focus is on education research that explores the ways in which mathematics and a mathematical worldview can influence choices, on educational, personal and societal levels. We take a broad view and raise questions about what it means to be mathematical in society, and we consider the multifaceted ways in which abilities to derive and interpret information presented mathematically …

Beyond Environmental Harm: Industry Claims, Lived Experiences, And The Impacts Of Gas Extraction, Martina Angela Caretta, Melissa Haeffner, Ryan Emanuel, Racheal Hood, Julia Seydel

Environmental Science and Management Faculty Publications and Presentations

The peer-reviewed literature presents overwhelming evidence that fossil fuel based energy infrastructure projects are responsible for lower residential property values, environmental destruction and pollution that decrease residents' quality of life. These projects also challenge local people's sense of identity and even the threat of such a project can make residents question their sense of place. As evidence, we first present a bibliographic analysis of the environmental impact statements for the Mountain Valley Pipeline in West Virginia and the Jordan Cove Energy Project in Oregon. We find that their approval processes relies on non-peer-reviewed, industry-funded claims that pipelines will bring economic …

Regiongrow3d: A Deterministic Analysis For Characterizing Discrete Three-Dimensional Landslide Source Areas On A Regional Scale, Nicolas W. Mathews, Ben A. Leshchinsky, Benjamin B. Mirus, Michael J. Olsen, Adam M. Booth

Geology Faculty Publications and Presentations

Regional-scale characterization of shallow landslide hazards is important for reducing their destructive impact on society. These hazards are commonly characterized by (a) their location and likelihood using susceptibility maps, (b) landslide size and frequency using geomorphic scaling laws, and (c) the magnitude of disturbance required to cause landslides using initiation thresholds. Typically, this is accomplished through the use of inventories documenting the locations and triggering conditions of previous landslides. In the absence of comprehensive landslide inventories, physics-based slope stability models can be used to estimate landslide initiation potential and provide plausible distributions of landslide characteristics for a range of environmental …

Evaluation Of Transplant Benefits With The Us Scientific Registry Of Transplant Recipients By Semiparametric Regression Of Mean Residual Life, Ge Zhao, Yanyuan Ma, Huazhen Lin, Yi Li

Mathematics and Statistics Faculty Publications and Presentations

Kidney transplantation is the most effective renal replacement therapy for end stage renal disease patients. With the severe shortage of kidney supplies and for the clinical effectiveness of transplantation, patient’s life expectancy posttransplantation is used to prioritize patients for transplantation; however, severe comorbidity conditions and old age are the most dominant factors that negatively impact posttransplantation life expectancy, effectively precluding sick or old patients from receiving transplants. It would be crucial to design objective measures to quantify the transplantation benefit by comparing the mean residual life with and without a transplant, after adjusting for comorbidity and demographic conditions. To address …

Application Of Participatory Process Mapping To Evaluate Environmental Decision-Making And Implementation, Karissa Courtney, Emily Rabung, Jennifer Brousseau, Antony S. Cheng, A. Paige Fischer, Harrison Fried, Matthew Hamilton, Federico Holm, Jordan Inskeep, Max Nielsen-Pincus, Multiple Additional Authors

Environmental Science and Management Faculty Publications and Presentations

Environmental governance outcomes hinge on the design and implementation of management decisions. Yet, available research methodologies can be limited in their ability to capture the complexity of decision-making and implementation processes and in turn predict and explain environmental governance outcomes. We present participatory process mapping as a method for examining the pathways that emerge and evolve over time that result in natural resource management decisions and on-the-ground outcomes, as perceived by participants in collaborative processes. The approach leverages a large-N comparative design, participatory diagraming within semi-structured interviews, and mental modeling toward a method that can fit into both quantitative and …

Matrix-Free High-Performance Saddle-Point Solvers For High-Order Problems In H (Div), Will Pazner, Tzanio Kolev, Panayot S. Vassilevski

Mathematics and Statistics Faculty Publications and Presentations

This work describes the development of matrix-free GPU-accelerated solvers for high-order finite element problems in . The solvers are applicable to grad-div and Darcy problems in saddle-point formulation, and have applications in radiation diffusion and porous media flow problems, among others. Using the interpolation–histopolation basis (cf. [W. Pazner, T. Kolev, and C. R. Dohrmann, SIAM J. Sci. Comput., 45 (2023), pp. A675–A702]), efficient matrix-free preconditioners can be constructed for the -block and Schur complement of the block system. With these approximations, block-preconditioned MINRES converges in a number of iterations that is independent of the mesh size and polynomial degree. The …

The Basic Dualism In The World: Object-Oriented Ontology And Systems Theory, Martin Zwick

Complex Systems Faculty Publications and Presentations

Graham Harman writes that the “basic dualism in the world lies…between things in their intimate reality and things as confronted by other things.” However, dualism implies irreconcilable difference; what Harman points to is better expressed as a dyad, where the two components imply one another and interact. This article shows that systems theory has long asserted the fundamental character of Harman’s dyad, expressing it as the union of internal structure and external function, which correspond exactly to what Levi Bryant, characterizing Harman’s views, refers to as the intra-ontic and the inter-ontic, respectively. After interpreting Harman’s dyad in terms of the …

Agnotology Of The E-Cigarette Industry: How The E-Cigarette Industry Continues The Tobacco Industry's Legacy Of Creating Controversy And Confusion Within The Scientific Community And The General Population, Calvin Lewis

University Honors Theses

The purpose of this paper is to determine the extent to which the e-cigarette industry follows in the footsteps of the tobacco industry's attempts to disrupt science and cause controversy. Four tactics are described that the tobacco industry uses to disrupt science: funding research that is designed to show results that support their position, criticizing and suppressing research that goes against their position, changing risk assessment and scientific research standards to fit their aims, and spreading data created by their interest groups to politicians and the nonacademic press. Evidence is found to show that both the tobacco industry and e-cigarette …

Sustainability In The Specialty Mushroom Industry And The Fight Against Single-Use Plastic: A Case Study, Amanda Newman

University Honors Theses

Specialty mushroom cultivator, Bridgetown Mushrooms, generates approximately 3 metric tons of polypropylene plastic waste a year. This is just a fraction of the 1-2 million metric tons created by the specialty mushroom industry annually. With only 10% of plastic waste being used as secondary materials, the majority of this waste ends up in landfills or in the environment. Through collaboration with employees within Bridgetown’s operation and government agency mentorship, it was determined that the most viable and ecological solution to reduce on-farm plastic waste within Bridgetown’s operation was to develop a reusable growing apparatus as a direct replacement for polypropylene …

Story Of Your Lazy Function's Life: A Bidirectional Demand Semantics For Mechanized Cost Analysis Of Lazy Programs, Li-Yao Xia, Laura Israel, Maite Kramarz, Nicholas Coltharp, Koen Claessen, Stephanie Weirich, Yao Li

Computer Science Faculty Publications and Presentations

Lazy evaluation is a powerful tool that enables better compositionality and potentially better performance in functional programming, but it is challenging to analyze its computation cost. Existing works either require manually annotating sharing, or rely on separation logic to reason about heaps of mutable cells. In this paper, we propose a bidirectional demand semantics that allows for extrinsic reasoning about the computation cost of lazy programs without relying on special program logics. To show the effectiveness of our approach, we apply the demand semantics to a variety of case studies including insertion sort, selection sort, Okasaki's banker's queue, and the …

Accretion Of Warm Chondrules In Weakly Metamorphosed Ordinary Chondrites And Their Subsequent Reprocessing, Alex M. Ruzicka, Richard C. Hugo, Jon M. Friedrich, Michael T. Ream

Geology Faculty Publications and Presentations

To better understand chondrite accretion and subsequent processes, the textures, crystallography, deformation, and compositions of some chondrite constituents in ten lithologies of different cluster texture strength were studied in seven weakly metamorphosed (Type 3) and variably shocked ordinary chondrites (Ragland—LL3 S1, Tieschitz—H/L3 S1, NWA 5421—LL3 S2, NWA 5205—LL3 S2, NWA 11905—LL3-5 S3, NWA 5781—LL3 S3, NWA 11351—LL3-6 S4) using optical and electron microscopy and microtomography techniques.

Results support a four-stage model for chondrite formation. This includes 1) limited annealing following collisions during chondrule crystallization and rapid cooling in space prior to accretion, as evidenced by olivine microstructures consistent with dislocation …

Toxicity Of Waterpipe Tobacco Smoking: The Role Of Flavors, Sweeteners, Humectants, And Charcoal, Nada O F Kassem, Robert M. Strongin, Andrea M. Stroup, Marielle C. Brinkman, Ahmad El-Hellani, Hanno C. Erythropel, Arash Etemadi, Maciej L. Goniewicz, Eleanore G. Hansen, Noura O. Kassem, Multiple Additional Authors

Chemistry Faculty Publications and Presentations

Waterpipe tobacco (WPT) smoking is a public health concern, particularly among youth and young adults. The global spread of WPT use has surged since the introduction of pre-packaged flavored and sweetened WPT, which is widely marketed as a safer tobacco alternative. Besides flavorants and sugars, WPT additives include humectants, which enhance the moisture and sweetness of WPT, act as solvents for flavors, and impart smoothness to the smoke, thus increasing appeal to users. In the United States (U.S.), unlike cigarette tobacco flavoring (with the exception of menthol), there is no FDA product standard or policy in place prohibiting sales of …

Synthesis And Computational Studies Of Α- And Δ-Substituted Macrocyclic Europium And Ytterbium Complexes, Delainey Amara Winder

Dissertations and Theses

The uses of macrocyclic lanthanide complexes are vast, with many targeted MRI contrast agents at the forefront of the field. Many of these are ParaCEST agents, which require exchangeable protons accessible on the macrocycle and the slow exchange of coordinated water molecules. The substitution at both the α- and δ-carbon on the amide pendant arm of these macrocyclic lanthanide complexes can lock bulky groups on the δ-carbon to a pseudo-axial position. When the α- and δ-carbons have the same chirality, the bulky group will be pseudo-equatorial, and when the chirality is opposed, the bulky group will be pseudo-axial. By performing …

Oregon State Rank Assessment For Midget Quillwort (Isoetes Minima), Lindsey K. Wise

Institute for Natural Resources Publications

Oregon state conservation status assessment for midget quillwort (Isoetes minima) using NatureServe methodology, 2024.

When Overextended Surface Allocation Turns To Groundwater: A Q Methodology Of Well Users In Oregon’S High Desert, Melissa Haeffner, Janet Cowal, Brandy Walker, Clare Mcclellan

Environmental Science and Management Faculty Publications and Presentations

As legal battles over surface water allocation in Klamath County, Oregon, USA have gained national attention, earning the name “Water Wars,” authorities have been increasingly turning to groundwater to compensate for water shortfalls. This case study aims to identify the nuanced perspectives of household groundwater well users who are affected by groundwater extraction. Using Q methodology, we uncover groundwater well users’ perceptions and to what extent they think water problems are dealt with fairly. We identify four water perspectives that differ in the degree to which respondents prioritize clean water accessibility, industry accountability, individual responsibility for water management, and trust …

Synoptic Drivers Of Extreme Precipitation In The Upper Yuba Watershed Of California, Emma Nichole Russell

Dissertations and Theses

California's annual precipitation is dependent on a few strong storms and in addition to its Mediterranean climate, leads to great variability in precipitation both within and across years. While efforts to reduce the impacts of extreme precipitation events have been implemented, forecasting for these events remains a challenge in regions with complex terrain and dynamic meteorological drivers. In order to improve forecasting and preparedness for such events, it is important to understand the range of atmospheric drivers that lead to extreme precipitation, particularly on a small scale. Here we aim to better understand the variety of meteorological mechanisms resulting in …