Digital Commons Network^™

Wet Meadow Plant Associations, Double O Unit, Malheur National Wildlife Refuge, Harney County, Oregon, John A. Christy

Institute for Natural Resources Publications

This report summarizes vegetation data collected in July 2015 in wet meadow and marshy habitats on the Double O Unit of Malheur National Wildlife Refuge (MNWR). Because vegetation sampled at the Double O was wetter and more alkaline than wet meadows sampled at the south end of the refuge in 2012 and 2013 (Christy 2014), data from the Double O Unit were analyzed and summarized separately. A total of 83 plots were sampled in 2015, and analysis of the data identified 14 plant associations: Alopecurus aequalis - Juncus balticus, Alopecurus pratensis - Potentilla anserina, Carex praegracilis - Juncus balticus, Cicuta …

Factors Influencing The Survival Of Outmigrating Juvenile Salmonids Through Multiple Dam Passages: An Individual-Based Approach, Timothy Elder, Christa M. Woodley, Mark A. Weiland, Angela L. Strecker

Environmental Science and Management Faculty Publications and Presentations

Substantial declines of Pacific salmon populations have occurred over the past several decades related to large-scale anthropogenic and climatic changes in freshwater and marine environments. In the Columbia River Basin, migrating juvenile salmonids may pass as many as eight large-scale hydropower projects before reaching the ocean; however, the cumulative effects of multiple dam passages are largely unknown. Using acoustic transmitters and an extensive system of hydrophone arrays in the Lower Columbia River, we calculated the survival of yearling Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) passing one, two, or three dams. We applied a unique index of biological characteristics …

Transdisciplinary Weed Research: New Leverage On Challenging Weed Problems?, N. Jordan, M. Schut, S. Grahan, J. N. Barney, D. Z. Childs, S. Christensen, R. D. Cousens, A. S. Davis, H. Eizenberg, David E. Ervin, C. Fernández-Quintanilla, L. J. Harrison, M. A. Harsch, S. Heijting, M. Liebman, D. Loddo, S. B. Mirsky, M. Riemens, P. Neve, D. A. Peltzer, M. Renton, M. Williams, J. Recasens, M. Sønderskov

Institute for Sustainable Solutions Publications and Presentations

Transdisciplinary weed research (TWR) is a promising path to more effective management of challenging weed problems. We define TWR as an integrated process of inquiry and action that addresses complex weed problems in the context of broader efforts to improve economic, environmental and social aspects of ecosystem sustainability. TWR seeks to integrate scholarly and practical knowledge across many stakeholder groups (e.g. scientists, private sector, farmers and extension officers) and levels (e.g. local, regional and landscape). Furthermore, TWR features democratic and iterative processes of decision-making and collective action that aims to align the interests, viewpoints and agendas of a wide range …

Clear Creek Estuary Restoration: Establishing An Ecological Monitoring Program And Baseline Conditions, Christine Butler-Minor

Environmental Science and Management Professional Master's Project Reports

Monitoring habitat conditions in the Clear Creek Estuary before the completion of the Bucklin Hill Bridge Project is a critical part of this ecosystem restoration planning and execution. The Clear Creek Trail Alliance (CCTA) is working with local partners to monitor the effects of the estuary restoration. In a wider effort to characterize salmonid habitat suitability of the estuary prior to the bridge replacement, CCTA would like to gather data related to water quality, beach/bank elevations, vegetation in the vicinity, and invertebrate diversity in the estuary. The development and implementation of this Clear Creek Estuary monitoring project provides an opportunity …

Bertrand Competition With Asymmetric Marginal Costs, Subhasish Dugar, Arnab Mitra

Economics Faculty Publications and Presentations

This paper tests the prediction of three discrete asymmetric duopoly price competition games in the laboratory. The games differ from each other in terms of the size of the cost asymmetry that induces a systematic variation in the difference between the firms’ marginal costs. While the standard theory requires the low-cost firm to set a price just equal to the high cost firm's marginal cost, which is identical across all three games, and win the entire market; intuition suggests that market price may increase with a decrease in the absolute difference between the two marginal costs. We develop a quantal …

Bayesian Methods For Comparing Species Physiological And Ecological Response Curves, Michael B. Ashcroft, Angélica Casanova-Katny, Kerrie Mengersen, Todd N. Rosenstiel, Johanna D. Turnbull, Jane Wasley, Melinda J. Waterman, Gustavo E. Zúñiga, Sharon A. Robinson

Biology Faculty Publications and Presentations

Many ecological questions require information on species' optimal conditions or critical limits along environmental gradients. These attributes can be compared to answer questions on niche partitioning, species coexistence and niche conservatism. However, these comparisons are unconvincing when existing methods do not quantify the uncertainty in the attributes or rely on assumptions about the shape of species' responses to the environmental gradient. The aim of this study was to develop a model to quantify the uncertainty in the attributes of species response curves and allow them to be tested for substantive differences without making assumptions about the shape of the responses. …

Characteristics Of Cannabis-Only And Other Drug Users Who Visit The Emergency Department, Susan I. Woodruff, Cameron T. Mccabe, Melinda Hohman, John D. Clapp, Audrey M. Shillington, Kimberly Eisenberg, C. Beth Sise, Edward M. Castillo, Theodore C. Chan, Michael J. Sise

Psychology Faculty Publications and Presentations

Emergency department (ED) settings have gained interest as venues for illegal drug misuse prevention and intervention, with researchers and practitioners attempting to capitalize on the intersection of need and opportunity within these settings. This study of 686 adult patients visiting two EDs for various reasons who admitted drug use compared daily cannabis-only users, nondaily cannabis-only users, and other drug users on sociodemographic and drug-related severity outcomes. The three drug use groups did not differ on most sociodemographic factors or medical problem severity scores. Forty-five percent of the sample was identified as having a drug use problem. ED patients who used …

Communication: Visualization And Spectroscopy Of Defects Induced By Dehydrogenation In Individual Silicon Nanocrystals, Dmitry A. Kislitsyn, Jon M. Mills, Vancho Kocevski, Sheng-Kuei Chiu, William J.I. Debenedetti, Christian F. Gervasi, Benjamen N. Taber, Ariel E. Rosenfield, Olle Eriksson, Ján Rusz, Andrea Mitchell Goforth, George V. Nazin

Chemistry Faculty Publications and Presentations

We present results of a scanning tunneling spectroscopy (STS) study of the impact of dehydrogenation on the electronic structures of hydrogen-passivated silicon nanocrystals (SiNCs) supported on the Au(111)surface. Gradual dehydrogenation is achieved by injecting high-energy electrons into individual SiNCs, which results, initially, in reduction of the electronic bandgap, and eventually produces midgap electronic states. We use theoretical calculations to show that the STS spectra of midgap states are consistent with the presence of silicon dangling bonds, which are found in different charge states. Our calculations also suggest that the observed initial reduction of the electronic bandgap is attributable to the …

The Influence Of Floodplain Restoration On Flow And Sediment Dynamics In An Urban River, Sangaralingam Ahilan, Mingfu Guan, Andrew Sleigh, Nigel G. Wright, Heejun Chang

Geography Faculty Publications and Presentations

A study of floodplain sedimentation on a recently restored floodplain is presented. This study uses a two-dimensional hydro-morphodynamic model for predicting flow and suspended-sediment dynamics in the downstream of Johnson Creek, the East Lents reach, where the bank of the river has been reconfigured to reconnect to a restored floodplain on a 0.26 km² (26-ha) site. The simulation scenarios include 10-, 50-, 100- and 500-year event-based deposition modelling of flood events and long-term modelling using the 64 historical flood events between 1941 and 2014. Simulation results showed that the restored floodplain significantly attenuates the upstream flood peak by up …

Trajectory Analysis Of Black Carbon In The Arctic Region, Kimberly Gottschalk

PSU McNair Scholars Online Journal

Black carbon (BC) is a troubling particulate. Commonly known as soot, BC forms through the incomplete combustion of fossil fuels, biofuels, and biomass. It has a very low albedo compared to natural particulates making it a very efficient absorber of solar radiation. As BC is deposited on snow and ice, albedo is decreased - enhancing solar heating and increasing meltwater production. With rising air temperatures, melting rates of polar ice are increasing and are being enhanced by BC, leading to accelerated global sea level rise.

This study aimed to document sources and deposition areas of BC in the Arctic. Utilizing …

Biomimetic Tools In Oxidative Metabolism: Characterization Of Reactive Metabolites From Antithyroid Drugs, Kudzanai Chipiso

Dissertations and Theses

Toxicities of sulfur-based drugs have been attributed to formation of highly reactive sulfur oxo-acids and depletion of glutathione by the formation of reactive metabolites. Metabolic activation of these sulfur centers to conceivably toxic reactive metabolites (RMs) that can covalently modify proteins is considered the initial step in drug-induced toxicity. Despite considerable effort and research, detection and characterization of these RMs during drug development and therapy remains a challenge. Methimazole (MMI) and 6-propyl-2-thiouracil (PTU) are two commonly used antithyroid, sulfur-based drugs. Though effective, these drugs are associated with idiosyncratic toxicity. PTU has acquired a black box warning and physicians are calling …

Aspirational Planning: A Statistical Model Of Hawthorne Bridge And Tilikum Crossing Bicycle Ride Counts, Robert Mccullough, Ramon Cabauatan, Jacob Gellman

Hatfield Graduate Journal of Public Affairs

Portland city planners have routinely planned for an increase in bicycle commutership and a decrease in automobile commutership. This paper discusses the latest data on Portland car and bicycle use. Portland and Multnomah County are observing an increase in single occupancy vehicle commuters, car ownership, and gasoline consumption. Bicycle use in Portland is found to have followed a logistic curve pattern since the early 1990s. The authors present an ordinary least squares model to explain bicycle ridership on the Hawthorne Bridge and the recently constructed Tilikum Crossing. When controlling for other factors such as weather and daylight, the Tilikum Crossing …

The Investigation And Optimization Of A Two-Heat-Pump System Incorporating Thermal Storage For Shaping Residential Heating Load, Emily Lord Barrett

Dissertations and Theses

Portland General Electric has proposed coupling one or more water tanks with two heat pumps in order to perform load-shifting in residential customer heating and cooling applications. By using the water tanks as a thermal storage unit, this project attempts to partially decouple energy consumption from generation to provide peak demand reduction and to better facilitate the integration of variable renewable energy resources. A scoping study was performed to evaluate the potential impact of this project if implemented in single family homes in Portland, Oregon. This study revealed that the system could provide meaningful savings in the cost of electricity …

Connecting To Nature, Community, And Self: A Conservation Corps Approach To Re-Engaging At-Risk Youth In Science Education, Sara Jo Linden

Dissertations and Theses

The social and environmental challenges of the coming decades will require that individuals possess environmental literacy: the understanding of natural systems combined with a sense of care for the earth, and the confidence and competency to act on its behalf. At the same time, disengaged youth need education environments that foster belonging and promote affective outcomes. The youth conservation corps model provides a natural context for engaging academically at-risk youth in environmental science education, while fostering connection to nature and student self-efficacy in ways that are experiential, relevant, and relationship-based. The focus of this study was a conservation corps program …

Stellar Works: Searching For The Lives Of Women In Science, Jennifer Elizabeth Woodman

Dissertations and Theses

While women have had a profound impact in the world of science, they struggle to gain an equal foothold in many science, technology, engineering, and mathematics (STEM) fields today. This has led to considerable public and private sector efforts to recruit women into these arenas. In order to understand how schools and nonprofits engage today's young women in STEM studies, this account includes time spent both in high school science classrooms and with ChickTech -- a Portland-based organization that works to provide a pathway into tech careers for high school-aged girls.

A historical perspective reveals that modern women aren't treading …

Empowering Students To Make Sense Of An Information Saturated World: The Evolution Of Information Searching And Analysis, James H. Wittebols

Communications in Information Literacy

How well students conduct research online is an increasing concern for educators at all levels but especially higher education. The paper describes the evolution of a course that grew from a unit within a course to a whole course that examines confirmation bias, information searching and the political economy of information as keys to becoming more information and media literate. After a key assignment in which students assess their own tendency to engage in confirmation bias, students choose a social justice issue to investigate across web, news and academic research resources. Designed to build good analytical skills in assessing the …

Identifying Threshold Concepts For Information Literacy: A Delphi Study, Lori Townsend, Amy R. Hofer, Silvia Lin Hanick, Korey Brunetti

Communications in Information Literacy

This study used the Delphi method to engage expert practitioners on the topic of threshold concepts for information literacy. A panel of experts considered two questions. First, is the threshold concept approach useful for information literacy instruction? The panel unanimously agreed that the threshold concept approach holds potential for information literacy instruction. Second, what are the threshold concepts for information literacy instruction? The panel proposed and discussed over fifty potential threshold concepts, finally settling on six information literacy threshold concepts.

The Terroir Of Pinot Noir Wine In The Willamette Valley, Oregon : A Broad Analysis Of Vineyard Soils, Grape Juice And Wine Chemistry, Kathryn Nora Barnard

Dissertations and Theses

Terroir is determined by a combination of factors in the vineyard including the grape varietal, geology and soil, soil hydrology, physiography, and climate. Although most studies have examined regional differences in wine flavors and associated provenance of wine based on chemistry, few have examined the chemistry of the soil and the ability to trace that chemistry to grape juice and, finally, to the wine. This dissertation examines what soil physical and chemical differences specific to this region might influence grape juice chemistry and wine chemistry.

Wine-grapes in the Willamette Valley, Oregon, are grown on three major soil parent materials: volcanic, …

Investigating The Potential Of Land Use Modifications To Mitigate The Respiratory Health Impacts Of No2: A Case Study In The Portland-Vancouver Metropolitan Area, Meenakshi Rao

Dissertations and Theses

The health impacts of urban air pollution are a growing concern in our rapidly urbanizing world. Urban air pollutants show high intra-urban spatial variability linked to urban land use and land cover (LULC). This correlation of air pollutants with LULC is widely recognized; LULC data is an integral input into a wide range of models, especially land use regression models developed by epidemiologists to study the impact of air pollution on human health. Given the demonstrated links between LULC and urban air pollution, and between urban air pollution and health, an interesting question arises: what is the potential of LULC …

Photoemission Electron Microscopy For Analysis Of Dielectric Structures And The Goos-Hänchen Shift, Theodore Axel Stenmark

Dissertations and Theses

Photoemission Electron Microscopy (PEEM) is a versatile tool that relies on the photoelectric effect to produce high-resolution electron images. Ultrafast pulse lasers allow for multi-photon PEEM where multiple visible or IR photons excite a single electron in a nonlinear process. The photoelectron yield in both cases is related to the near-field region of electromagnetic fields at the surface of the sample. We use this ability here to analyze wave propagation in a linear dielectric waveguide with wavelengths of 410 nm and 780 nm. The propagation constant of the waveguide can be extracted from interference patterns created by light propagating in …

Large Length Scale Capillary Fluidics: From Jumping Bubbles To Drinking In Space, Andrew Paul Wollman

Dissertations and Theses

In orbit, finding the "bottom" of your coffee cup is a non-trivial task. Subtle forces often masked by gravity influence the containment and transport of fluids aboard spacecraft, often in surprising non-intuitive ways. Terrestrial experience with capillary forces is typically relegated to the micro-scale, but engineering community exposure to large length scale capillary fluidics critical to spacecraft fluid management design is low indeed. Low-cost drop towers and fast-to-flight International Space Station (ISS) experiments are increasing designer exposure to this fresh field of study. This work first provides a wide variety of drop tower tests that demonstrate fundamental and applied capillary …

An Examination Of School Readiness: How Is The Construct Defined For Children Who Are Blind?, Lisa Joann Mcconachie

Dissertations and Theses

An increased focus on school readiness exists as students enter public school for the first time. Given unique challenges for students who are blind and use braille, school readiness in the transition to and preparation for kindergarten is even more critical to their future academic success. If children who are blind and use braille as their primary learning medium have the necessary school readiness skills entering kindergarten, they will be better prepared to participate in the academic classroom. There is a need for additional research to illuminate the skills needed for school readiness for children who are blind and use …

Daytime Variation Of Urban Heat Islands: The Case Study Of Doha, Qatar, Yasuyo Makido, Vivek Shandas, Salim Ferwati, David J. Sailor

Urban Studies and Planning Faculty Publications and Presentations

Recent evidence suggests that urban forms and materials can help to mediate temporal variation of microclimates and that landscape modifications can potentially reduce temperatures and increase accessibility to outdoor environments. To understand the relationship between urban form and temperature moderation, we examined the spatial and temporal variation of air temperature throughout one desert city—Doha, Qatar—by conducting vehicle traverses using highly resolved temperature and GPS data logs to determine spatial differences in summertime air temperatures. To help explain near-surface air temperatures using land cover variables, we employed three statistical approaches: Ordinary Least Squares (OLS), Regression Tree Analysis (RTA), and Random Forest …

On The Observability Of Bottom Topography From Measurements Of Tidal Sea Surface Height, Edward D. Zaron

Civil and Environmental Engineering Faculty Publications and Presentations

of whether features of the ocean bottom topography can be identified from measurements of water level is investigated using a simplified one-dimensional barotropic model. Because of the nonlinear dependence of the sea surface height on the water depth, a linearized analysis is performed concerning the identification of a Gaussian bump within two specific depth profiles, (1) a constant depth domain, and, (2) a constant depth domain adjoining a near-resonant continental shelf. Observability is quantified by examining the estimation error in a series of identical-twin experiments varying data density, tide wavelength, assumed (versus actual) topographic correlation scale, and friction. For measurements …

An Ensemble Approach To Weak-Constraint Four-Dimensional Variational Data Assimilation, Jeremy A. Shaw, Dacian Daescu

Mathematics and Statistics Faculty Publications and Presentations

This article presents a framework for performing ensemble and hybrid data assimilation in a weak-constraint four-dimensional variational data assimilation system (w4D-Var). A practical approach is considered that relies on an ensemble of w4D-Var systems solved by the incremental algorithm to obtain flow-dependent estimates to the model error statistics. A proof-of-concept is presented in an idealized context using the Lorenz multi-scale model. A comparative analysis is performed between the weak- and strong-constraint ensemble-based methods. The importance of the weight coefficients assigned to the static and ensemble-based components of the error covariances is also investigated. Our preliminary numerical experiments indicate that an …

Wildfire Risk As A Socioecological Pathology, A. Paige Fischer, Thomas A. Spies, Toddi A. Steelman, Cassandra Moseley, Bart R. Johnson, John D. Bailey, Alan A. Ager, Patrick Bourgeron, Susan Charnley, Brandon M. Collins, Jeffrey D. Kline, Jessica E. Leahy, Jeremy S. Littell, James D. A. Millington, Max Nielsen-Pincus, Christine S. Olsen, Travis B. Paveglio, Christopher I. Roos, Michelle M. Steen-Adams, Forrest R. Stevens, Jelena Vukomanovic, Eric M. White, David Bowman

Environmental Science and Management Faculty Publications and Presentations

Wildfire risk in temperate forests has become a nearly intractable problem that can be characterized as a socioecological “pathology”: that is, a set of complex and problematic interactions among social and ecological systems across multiple spatial and temporal scales. Assessments of wildfire risk could benefit from recognizing and accounting for these interactions in terms of socioecological systems, also known as coupled natural and human systems (CNHS). We characterize the primary social and ecological dimensions of the wildfire risk pathology, paying particular attention to the governance system around wildfire risk, and suggest strategies to mitigate the pathology through innovative planning approaches, …

Scientifically Defensible Fish Conservation And Recovery Plans: Addressing Diffuse Threats And Developing Rigorous Adaptive Management Plans, Kathleen G. Maas-Hebner, Carl B. Schreck, Robert M. Hughes, J. Alan Yeakley, Nancy Molina

Environmental Science and Management Faculty Publications and Presentations

We discuss the importance of addressing diffuse threats to long-term species and habitat viability in fish conservation and recovery planning. In the Pacific Northwest, USA, salmonid management plans have typically focused on degraded freshwater habitat, dams, fish passage, harvest rates, and hatchery releases. However, such plans inadequately address threats related to human population and economic growth, intra- and interspecific competition, and changes in climate, ocean, and estuarine conditions. Based on reviews conducted on eight conservation and/or recovery plans, we found that though threats resulting from such changes are difficult to model and/or predict, they are especially important for wide-ranging diadromous …

Can Significant Trends Be Detected In Surface Air Temperature And Precipitation Over South America In Recent Decades?, Daniel De Barros Soares, Huikyo Lee, Paul C. Loikith, Armineh Barkhordarian, Carlos R. Mechoso

Geography Faculty Publications and Presentations

Trends in near-surface air temperature and precipitation over South America are examined for the periods 1975–2004 and 1955–2004, respectively, using multiple observational and climate model data sets. The results for observed near-surface air temperature show an overall warming trend over much of the continent, with the largest magnitudes over central Brazil. These observed trends are found to be statistically significant using pre-industrial control simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) as the baseline to estimate natural climate variability. The observed trends are compared with those obtained in natural-only CMIP5 simulations, in which only natural forcings …

Research & Strategic Partnerships: Quarterly Review, Volume 3, Issue 2, Portland State University. Research & Strategic Partnerships

Portland State Research Magazine

Portland State University plays a central role in our city’s transformation into the country’s leading laboratory for transportation innovation. Starting over a decade ago, our engineering and urban studies researchers began receiving federal funding to study the connections between the ways people get around in cities and their quality of life. This issue of the RSP Quarterly Review highlights this growing body of work, focusing on the contributions made by the Transportation Research and Education Center, or TREC.

Development Of Middle School Teachers' Knowledge And Pedagogy Of Justification: Three Studies Linking Teacher Conceptions, Teacher Practice, And Student Learning, Carolyn Mccaffrey James

Dissertations and Theses

Justification and argumentation have been identified as important mathematical practices; however, little work has been done to understand the knowledge and pedagogy teachers need to support students in these ambitious practices. Data for this research was drawn from the Justification and Argumentation: Growing Understanding in Algebraic Reasoning (JAGUAR) project. JAGUAR was a multi-year research and professional development project in which 12 middle school math teachers and a group of researchers explored the knowledge and pedagogy needed to support student justifications. This dissertation consists of three case study analyses. The first paper describes the development of teacher conceptions of justification, including …