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Edge Percolation Centrality: A New Measure to Quantify the Influence of Edges During Percolation in Networks
No full textNumerous centrality measures exist to quantify the influence of edges within a network, with edge betweenness being one of the more well-known measures. However, such measures are inadequate in network percolation scenarios (e.g., the transmission of a disease over a transportation network of highways) as they fail to consider the changing percolation states of edges over time. This paper addresses this limitation by extending percolation centrality, a measure originally developed to evaluate the influence of vertices during a percolation process (i.e., a dynamic spread of a contagion) in the network, to the edge level. The proposed measure, edge percolation centrality, captures both the topological connectivity of the network as well as the percolation states of the edges. Although the algorithm’s observed complexity of O(|V|3.57) makes it computationally intensive, the utility of the proposed edge measure is evident in its application to both synthetic and real-world networks undergoing percolation processes
Urban Wildlife in Your Backyard: Community Experiences With Coyotes and Outdoor Cats
No full textUrbanization reshapes ecological processes by fragmenting habitat and altering patterns of human-wildlife interaction, often reducing biodiversity. However, at the household scale, residential yards can either enhance or inhibit ecological connectivity - functioning as informal habitat stepping stones or barriers to wildlife. This thesis examines how residents\u27 environmental attitudes, wildlife experiences, and socio-demographic characteristics influence yard-level behaviors and shape the presence of urban-adapted wildlife species, particularly coyotes and domestic cats, across the Portland, Oregon metropolitan region. A mixed-methods, social-ecological framework guided the analysis, integrating survey data from 244 households with wildlife detections from motion-triggered cameras (Urban Wildlife Information Network, UWIN), citizen science reports (Portland Urban Coyote Project, PUCP), and U.S. Census-based demographic data within 0.5- and 1-mile spatial buffers. Survey responses were used to construct indices of environmental values (Stewardship, Biocentric, and Utilitarian) and yard behaviors (wildlife-encouraging, discouraging, and neutral). Cronbach\u27s Alpha confirmed high internal reliability of the composite measures, which were subsequently analyzed through multiple and stepwise regression models. Results showed that Stewardship values were the strongest predictors of wildlife-supportive yard features - including native vegetation, bird feeders, and unstructured elements like wood piles - while Utilitarian values were weakly associated with deterrent features such as fences and impervious surfaces. Biocentric attitudes also correlated with higher habitat complexity. Although some behavioral patterns were associated with the frequency of seeing or hearing coyotes and cats, lived experiences were consistently weaker predictors than environmental values.
Correlations and regression models also revealed that demographic context significantly shaped wildlife detection patterns. Neighborhoods with higher percentages of young adults and residents holding graduate degrees were more likely to report or detect coyotes and cats, while lower-income and older populations were associated with fewer detections. Notably, PUCP coyote reports showed strong positive correlations with educational attainment and the proportion of Black and Asian residents, while income levels exhibited a negative relationship with coyote sightings across both survey and citizen science data. These relationships were confirmed through negative binomial regression models, underscoring the explanatory power of demographic structure. To assess concordance among the different data sources, Pearson and Spearman correlations and Welch\u27s t-tests were used to compare detection values across survey-reported sightings, UWIN detections, and PUCP reports. While all three methods confirmed coyote and cat presence, correlation coefficients were moderate at best, and significant differences in mean detections were found between methods. These discrepancies highlight the importance of triangulating data collection approaches when evaluating urban wildlife presence, as each method reflects different spatial biases and observational limitations.
Taken together, these findings demonstrate that individual yard management decisions are more strongly influenced by attitudinal orientations than by direct wildlife encounters, and that residential areas, through their varied social and physical characteristics, can act as extensions of broader ecological networks. This conclusion is supported by consistent associations between demographic variables, environmental features, and the presence of wildlife-encouraging or discouraging yard behaviors. GIS-linked analyses revealed that the spatial distribution of wildlife sightings was not random, but instead followed patterns shaped by both environmental context and neighborhood demographic composition. Without integrating behavioral, demographic, and ecological data, such cross-scale relationships would remain obscured. This thesis underscores the need for interdisciplinary approaches in urban ecology and provides actionable insights for city planners, wildlife managers, and conservation educators - for example, designing neighborhood specific education campaigns or targeting stewardship initiatives toward communities with lower access to green space or higher prevalence of outdoor cats. As urban development continues, private yards will play an increasingly critical role in supporting biodiversity and maintaining ecological connectivity across metropolitan landscapes
Dilemmas Encountered While Planning Social And/or Political Elementary Mathematics Tasks
No full textA mathematical task rooted in social and/or political contexts has the potential to engage students in exploring their own real-ities and learning about the realities of others while building their mathematical knowledge. While there are planning and in-structional practices recommended for these types of tasks, no single practice can fully capture the nuances and challenges thatteachers might encounter. Therefore, this study identified dilemmas encountered by a team of mathematics education research-ers while planning a mathematical task rooted in social and/or political contexts. Using qualitative analysis, the researchersidentified three planning dilemmas: (a) what social and/or political goal to establish, (b) how might students respond to the task,and (c) which language to privilege in the task. These dilemmas were connected to the core planning practices of establishingmathematical and social and/or political goals, designing a task, and anticipating student thinking
2025 Commencement College of Engineering and Computer Science Ceremony Video
No full textVideo presentation of the PSU Maseeh College of Engineering and Computer Science Commencement ceremony, held June 13, 2025, at the Viking Pavilion at Portland State University.https://pdxscholar.library.pdx.edu/commencement_2020s/1013/thumbnail.jp
Industries, Self-Rated Health, and Status Characteristics: An Exploration of Health in Industries at the Intersection of Race/Ethnicity, Gender, and Disability
No full textWhile industries, occupations, and health outcomes have been widely studied, research has neglected self-rated health (SRH) and the intersectionality of different status characteristics in various industries. Using an IPUMS version of the Current Population Survey, this study explores the possible relationships between industries and SRH. More specifically, it seeks to find if workers\u27 disability status, racial minority status, or gender moderates (i.e., differentiates) the relationship between their industry and SRH. Findings show that certain industries are significant predictors of SRH, and that women with disabilities working in Mining and Construction, and Business and Repair Service have significantly worse SRH than men with no disabilities working in Finance, Insurance, and Real Estate. Racial minorities with disabilities did not have significantly different SRH in any industry compared to their counterparts, going against hypothesized results
Justice Impacted Mothers: An Autoethnographic Study Exploring the Impacts of Quality Prison Visitation with Children
No full textThis study explores the impacts of in-person visitation at correctional facilities and how the quality of this contact affects relationships between justice impacted mothers and their children. Little is known about these nuanced lived experiences as revealed by qualitative data and from someone who is mothering during incarceration. The literature on maternal incarceration is vast, but relies heavily on quantitative data. Existing research indicates facility visits, particularly those of high quality, offer constructive benefits such as reductions in maternal recidivism rates. However, separation during incarceration has shown higher risks for adolescent substance abuse, behavioral, and academic struggles. This study expands upon prior scholarship by utilizing the qualitative research framework via autoethnography and addresses the multidimensionality of visiting experiences through the authors firsthand encounters. These findings could inform stakeholders of processes to improve mothering from the inside, with the aim of structuring frameworks that foster quality visitation environments, and thereby, strengthen relationships between mother/child, while extending benefits for communities, both inside and outside of prison walls
Biodiversity Conservation Depends on the Expansion of Taxonomy and Systematics Research
No full textDespite mammals constituting fewer than 0.3% of all described species, their conservation is compelling for a number of reasons. They contribute to biodiversity and are important in maintaining and regulating ecological communities. Many mammals have significant cultural and economic value, serving as sources of food, medicine, and tourism revenue. Furthermore, the conservation of mammals often leads to the protection of entire habitats, benefiting numerous other species and preserving ecosystem services that are critical for human well- being. Humans share a unique evolutionary history with other mammal species, making their preservation important for scientific research, education, and understanding of our own biology and evolution. In spite of this, mammalian biodiversity is at severe risk, with 26% of all mammal species threatened with extinction. Here, we propose to use a 4-step framework with which to approach conservation strategy for mammalian biodiversity. The framework is structured and based on a protocol initially established from the standpoint of parasites by Daniel R. Brooks and collaborators in 2014. The 4 key phases are documentation (species discovery and specimen collection); assessment (species relationships, genetic diversity, and climate change vulnerability); monitoring (tracking populations and habitats over time); and action (addressing the taxonomic impediment—the lack of human and financial resources to undertake taxonomy, as well as the discrepancy between real number of existing species and human knowledge of biodiversity—and expanding protected areas). The successful integration of politics, politicians, and stakeholders into the process of conservation is critical to the success of the protocol because of the requirement to enact policy. And the urgency is now, because nothing is more vital to the human condition than preservation of biodiversity
Connecting Canopies: Portland-Vancouver Regional Urban Tree Policy and Program Summary (Lunch and Learn)
No full textTed presented in greater detail on his 2025 UERC presentation:
Trees are crucial green infrastructure in a changing climate, but urban trees face an array of threats as cities grow and redevelop. Without plans, policies and programs for their conservation, tree loss undermines the long-term health and viability of urban communities.
We developed a framework to summarize and compare urban tree policies and programs for the Portland-Vancouver metropolitan region, using interviews and a cross-comparison of codes, investment and staff levels, and other features. Across the region, urban tree policies and programs differ among 42 distinct jurisdictions. Most communities have tree codes, but they vary in their strength and comprehensiveness. Staffing and management levels for trees also vary and are frequently split across departments within a jurisdiction. Few jurisdictions have tree or canopy cover inventories, and fewer use these inventories to direct tree management and investments. Investment levels in trees are difficult to ascertain and variable from one jurisdiction to another. Community partnerships and workforce development programs for trees are also inconsistent and frequently absent. Most community partnerships rely on volunteers, and few invest in jobs to plant and care for trees in low tree canopy settings.
Despite their ecological significance, urban tree policy and program information for the Portland-Vancouver region is difficult to access, and governance is fragmented with no minimum standards of protection or care. We compared our findings with two prior regional urban tree policy and program assessments from 2000 and 2010, to suggest that limited progress has been made over the past 20 years
State of the Climate in 2024: the Arctic
No full textThe Arctic environment in 2024 continued on a trajectory that has put it in a state far different from that of the twentieth century. Ongoing accumulation of greenhouse gases in the atmosphere continues to quickly warm the Arctic, resulting in rapid changes in the cryosphere that are driving cascading impacts to climate, ecological, and societal systems