Portland State University
  • Portland, OR, United States
Recent publications
In earthquake-prone regions such as the United States’ Pacific Northwest, post-event damage assessment tools are needed to enable safe and speedy recovery missions. Currently, damage assessment is performed mainly by visual inspection and often impossible for structural members that are inaccessible, such as deep foundations or interior members hidden by cladding. This research explores the possibility of using embedded ultrasonic transducers to monitor reinforced concrete members for damage progression under reverse-cyclic loading. The proposed approach uses a combination of passive and active ultrasonic stress wave monitoring approaches. The former, commonly referred to as acoustic emission monitoring, captures the energy released from active fracture sources. The latter is based on traditional and coda ultrasonic stress wave monitoring, which can take advantage of the highly sensitive diffuse portion of recorded waveforms to capture minute changes in a material. In this paper we introduce select results from a full-scale column-footing subassembly that was tested in the laboratory using a reverse-cyclic lateral loading protocol representative of a subduction zone earthquake with varying axial loading. A combination of surface-mounted and embedded transducers was employed to monitor the specimen throughout the loading process. The findings demonstrate the complementary information that may be gained from the proposed combined monitoring approach to characterize damage progression in reinforced concrete members.
Background: Patients report that familial support can facilitate initiation and maintenance of antiretroviral therapy (ART) and medications for opioid use disorder (MOUD). However, providing such support can create pressure and additional burdens for families of people with opioid use disorder (OUD) and HIV. We examined perspectives of people with HIV receiving treatment for OUD in Vietnam and their family members. Methods: Between 2015 and 2018, we conducted face-to-face qualitative interviews with 44 patients and 30 of their family members in Hanoi, Vietnam. Participants were people living with HIV and OUD enrolled in the BRAVO study comparing HIV clinic-based buprenorphine with referral to methadone treatment at 4 HIV clinics and their immediate family members (spouses or parents). Interviews were professionally transcribed, coded in Vietnamese, and analyzed using a semantic, inductive approach to qualitative thematic analysis. Results: Family members of people with OUD and HIV in Vietnam reported financially and emotionally supporting MOUD initiation and maintenance as well as actively participating in treatment. Family members described the burdens of supporting patients during opioid use, including financial costs and secondary stigma. Conclusions: Describing the role of family support in the lives of people living with OUD and HIV in the context of Vietnam enriches our understanding of their experiences and will support future treatment efforts targeting the family unit.
This paper analyzes the impact of supply-side abortion restrictions on aggregate abortion and birth rates in the USA. Specifically, I exploit state and time variation in the implementation of the first targeted regulation of abortion provider (TRAP) law in a state to identify the effects of the laws. I find that TRAP laws are associated with a reduction in the abortion rate of approximately 5% the year the first law is implemented, and an average reduction of 11–14% in subsequent years. There is also evidence that TRAP laws increased birth rates by 2–3%, which accounts for approximately 80–100% of the observed decline in abortion rates.
This paper presents a computational design exploration method called GA+TRIZ, which aids designers in defining the design problem clearly, making a parametric model where pertinent variables are included, obtaining a series of suitable solutions, and resolving existing conflicts among design objectives. The goal is to include the designer's qualitative and performance-based quantitative design goals in the design process, while promoting innovative ideas for resolving contradictory design objectives. The method employed is a Genetic Algorithm (GA), earlier implemented in an automated design exploration process called ParaGen, in combination with the Theory of Inventive Problem Solving (TRIZ), a novel methodology to assist architects and structural engineers in the conceptual phase of design. The GA+TRIZ method promotes automated design exploration, investigation of unexpected solutions, and continuous interaction with the computational generating system. Finally, this paper presents two examples that illustrate how the GA+TRIZ method assists designers in problem structuring, design exploration, and decision-making.
With the proliferation of electric scooters (e-scooters) in cities across the world, concerns continue to arise about their parking spots on sidewalks and other public spaces. Research has looked at e-scooter parking compliance and compared compliance to other mobility devices, but research has not yet examined the impacts of the built environment on parking compliance. Using a field observation dataset in Portland, Oregon, and novel GIS data, we attempt to understand the spatial distribution of e-scooter parking and the impact of built features on parking compliance, offering recommendations for policymakers and future research. The results of our study show that 76% of e-scooters observed fail at least one of the Portland’s parking compliance requirements and 59% fail at least two criteria. However, compliance varies spatially and by violation type, indicating that parking compliance (or non-compliance) is dependent on features of the built environment. Parking compliance is significantly higher on blocks with designated e-scooter parking than blocks without designated e-scooter parking. A statistically significant relationship is observed between the amount of legally parkable area on a city block and parking compliance. Parking compliance increases with larger percentages of legally parkable area. This finding can help policymakers prioritize dedicated e-scooter parking for blocks with limited legally parkable area.
The ability of a suite of models contributing to the sixth phase of the Coupled Model Intercomparison Project (CMIP6) to simulate observed large-scale atmospheric circulation patterns over the Pacific Northwest of North America is evaluated. Twelve representative patterns of 500-hPa geopotential height (Z500) anomalies are identified using the self-organizing map method applied to reanalysis. CMIP6 Z500 anomalies from simulations of the historical period are mapped to each reanalysis-derived pattern, and the resulting differences between patterns, as well as differences in frequency of pattern occurrence, are quantified. In general, models are able to simulate the range of Z500 patterns with reasonable fidelity, although model skill varies across the 25-member ensemble. Surface temperature and precipitation anomalies associated with each Z500 pattern are found to also be reasonably simulated by the models, with some biases noted. This boosts confidence that the models are simulating temperature and precipitation patterns for the correct physical reasons. The models exhibit a range of skill at simulating pattern occurrence frequency and pattern persistence, with more agreement in winter than summer. Results indicate that the CMIP6 models are appropriate for assessing future projections of key atmospheric circulation patterns and their impacts on temperature and precipitation over the region.
A learning experience designed for the Next Generation Science Standards (NGSS) should integrate the Science & Engineering Practices and Crosscutting Concepts (CCCs) with science content. Such three-dimensional learning engages students in the epistemic components of the scientific process. Whether the Practices and CCCs are used in epistemically meaningful ways to build more expert-like understanding and behaviors is context dependent. The NGSS defines learning progressions for the Practices and CCCs, but they do not provide the detail needed to build activities within the grade bands. It is also up to curriculum developers to decide how to incorporate the Practices and CCCs using technology in domain-specific inquiry contexts. We document the development and evaluation of the week-long middle school summer Camp NANO, where campers participated in an observational investigation of a stream habitat from the macro-to-nano scale using the scanning electron microscope (SEM) as well as produced an interactive Virtual Field Environment (VFE) communication of the stream environment. This pilot is an example of a domain-specific authentic scientific inquiry experience built around three-dimensional learning as guided by the novice-to-expert literature to meet the NGSS middle school learning targets of the selected Practices and CCCs. We found that it was possible to build an activity plan that authentically incorporated and integrated the Practices and CCCs with the SEM and VFE, and that the involvement with the SEM and VFE in association with the observational investigation facilitated expert-like thinking and behaviors towards the selected Practices and CCCs.
This paper addresses the study and applications of polyhedral duality in locally convex topological vector (LCTV) spaces. We first revisit the classical Rockafellar’s proper separation theorem for two convex sets one of which is polyhedral and then present its LCTV extension replacing the relative interior by its quasi-relative interior counterpart. Then we apply this result to derive enhanced calculus rules for normals to convex sets, coderivatives of convex set-valued mappings, and subgradients of extended-real-valued functions under certain polyhedrality requirements in LCTV spaces by developing a geometric approach. We also establish in this way new results on conjugate calculus and duality in convex optimization with relaxed qualification conditions in polyhedral settings. Our developments contain significant improvements to a number of existing results obtained by Ng and Song (Nonlinear Anal. 55, 845–858, 12).
Purpose: Mean length of utterance (MLU) is one of the most widely reported measures of syntactic development in the developmental literature, but its responsiveness in young school-age children’s language has been questioned, and it has been shown to correlate with nonsyntactic measures. This study tested the extent to which MLU shows measurement properties of responsiveness and construct validity when applied to language elicited from elementary school children. Method: Thirty-two typically developing children in two age groups (5 and 8 years) provided four short language samples each. Language samples were elicited in a question–answer context and a narrative context. MLU was calculated with both morpheme and word counts. Other established measures of syntactic complexity (clausal density [CD], developmental level [D-Level], mean length of clause [MLC]) and lexical diversity (lexical density, moving- average type–token ratio, number of different words) were also calculated. Results: Linear mixed-effects analyses revealed that MLU varied systematically with discourse context and children’s age group. The syntactic measures, CD and MLC, were found to vary systematically with MLU. None of the lexical diversity measures varied systematically with MLU. Conclusion: Results suggest that MLU is a responsive and valid measure of children’s syntactic development across age and discourse context during the early school-age years.
Purpose This study compared global coherence (GC) in individuals with Parkinson's disease (PD) to a healthy older adult (HOA) group during single (sitting) and dual (stationary cycling) tasks. Additionally, it explored the relationship between GC and cognition in PD. Method Thirty-seven individuals with PD and 19 HOAs participated in the prospective, cross-sectional study. Participants completed discourse monologues elicited using published prompts while seated and while pedaling a stationary bicycle. Four rating levels of GC were analyzed (GC1 = no relationship to the topic, GC2 = remote relationship, GC3 = conditional relationship, and GC4 = complete relationship) using a published protocol with good interrater reliability and test–retest stability. Participants completed a battery of cognitive tasks, from which four latent factors were extracted: processing speed, working memory, inhibition, and updating. Results Linear mixed modeling identified significant effects of GC level and GC level interactions with group, processing speed, and inhibition. The Group × GC Level interaction reflected that the PD group had a higher proportion of GC2 and GC1 utterances and fewer GC4 utterances than the HOA group. No differences between single and dual task conditions were found. Faster speed of processing predicted more GC4 utterances, whereas slower speed of processing predicted more G1 utterances. Better inhibition predicted fewer GC2 utterances. Group also predicted GC4 and GC2 proportions. Conclusions Individuals with PD experienced greater difficulties with GC than HOAs. Processing speed and inhibition contributed significantly to GC across groups. Analysis of GC should be considered an informative addition to assessment of communicative effectiveness in PD. Supplemental Material https://doi.org/10.23641/asha.20416056
Background When deep-sea hydrothermal fluids mix with cold oxygenated fluids, minerals precipitate out of solution and form hydrothermal deposits. These actively venting deep-sea hydrothermal vent deposits support a rich diversity of thermophilic microorganisms which are involved in a range of carbon, sulfur, nitrogen, and hydrogen metabolisms. Global patterns of thermophilic microbial diversity in deep-sea hydrothermal ecosystems have illustrated the strong connectivity between geological processes and microbial colonization, but little is known about the genomic diversity and physiological potential of these novel taxa. Here we explore this genomic diversity in 42 metagenomes from four deep-sea hydrothermal vent fields and a deep-sea volcano collected from 2004 to 2018, and document their potential implications in biogeochemical cycles. Results Our dataset represents 3,635 metagenome-assembled genomes encompassing 511 novel genera, with 395 Bacteria and 116 Archaea, providing many targets for cultivation of novel archaeal and bacterial families. Notably, 52% (206) of the novel bacterial genera and 72% (84) of the novel archaeal genera were found at the deep-sea Brothers volcano, many of which were endemic to the volcano. We report some of the first examples of medium to high-quality MAGs from phyla and families never previously identified, or poorly sampled, from deep-sea hydrothermal environments. We greatly expand the novel diversity of Thermoproteia, Patescibacteria (Candidate Phyla Radiation, CPR), and Chloroflexota found at deep-sea hydrothermal vents and identify a small sampling of two potentially novel phyla, designated JALSQH01 and JALWCF01. Metabolic pathway analysis of metagenomes provides insights into the prevalent carbon, nitrogen, sulfur and hydrogen metabolic processes across all sites, and illustrates sulfur and nitrogen metabolic ‘handoffs’ in community interactions. We confirm that Campylobacteria and Gammaproteobacteria occupy similar ecological guilds but their prevalence in a particular site is driven by shifts in the geochemical environment. Conclusion Our study of globally-distributed hydrothermal vent deposits provides a significant expansion of microbial genomic diversity associated with hydrothermal vent deposits and highlights the metabolic adaptation of taxonomic guilds. Collectively, our results illustrate the importance of comparative biodiversity studies in establishing patterns of shared phylogenetic diversity and physiological ecology, while providing many targets for enrichment and cultivation of novel and endemic taxa.
As migration and displacement continue to increase around the world, guidelines are needed clarifying how school counselors can use their power and privilege in working with refugee students and their families across K-12 education, more so in relation to the COVID-19 pandemic. We introduce the Refugee Well-Being Project intervention to school counselors and school counselor interns, focusing on the social determinants of health impacting the overall well-being of refugee students.
Activation of the complement pathway results in the production of bioactive C3a, a product of C3 cleavage, which interacts with membrane-bound receptor C3aR to regulate innate immune cell function and outcome of bacterial infection. Specifically, previous research has identified mechanistically distinct and cell type–specific roles for C3aR in regulating innate immune cell inflammatory state, antimicrobial killing capacity, and metabolism. Historically, the production of C3a has been relegated to the serum; however, recent studies have provided evidence that various cell types can produce intracellular C3a that stimulates intracellular C3aR. In light of these new results, it is imperative that we revisit previous studies regarding the role of C3aR in controlling bacterial infections and analyze these results in the context of both extracellular and intracellular C3a production and C3aR activation. Thus, this review will cover specific roles of C3aR in driving cell type–specific and tissue specific responses during bacterial infections and emphasize the contribution of the C3a–C3aR axis in regulating host resistance to bacterial infection.
Paid leave confers health benefits to new parents and their children, but the absence of a national paid family leave policy in the United States has left workers to navigate a patchwork of paid and unpaid parental leave benefits accessed through their employers. As public and private paid leave policies expand across the US, it is imperative to determine how these benefits impact leave taking behaviors among new parents. We use sequence and cluster analyses of administrative time-keeping records to detail parental leave-taking during the first 180 days after adding a child among employees of a large public-sector organization with a new paid parental leave policy. Results show that the additional paid leave benefits replaced some of the unpaid leave women were taking and also lengthened their total leave duration. For men, who were only taking paid leave, the additional benefits allowed them to save their sick leave but left total leave duration unaffected. This study highlights the complex ways paid leave policies impact leave-taking among new parents. As more state and municipal governments consider paid family leave policies, understanding the interplay between these policies and existing organizational structures is critical to maximize the benefits across the workplace and limit unintended consequences.
Surface wetting phenomena impact chemistry, physics, biology, and engineering. The wetting behaviors of partially-miscible binary liquid systems are especially complex. Here we report evidence of universal behavior in the divergence of wetting layer growth at liquid-vapor interfaces of the cyclohexane + aniline, hexane + o-toluidine, and methanol + carbon disulfide systems. Layer growth on the micron scale was followed using visible light scattering from stirred samples. Layer thicknesses diverged with decreasing temperature when coexistence was approached from the one-phase region, but only for solutions richer in the higher density / higher surface tension component. The onset of divergence was <1 K above the bulk coexistence temperature; nearer the critical composition, the onset temperature was the critical temperature itself. All three systems showed identical divergent wetting properties after variable normalization. In contrast, no divergent wetting layer formation was seen in the benzene + 1,2-propanediol or water + phenol systems. The mathematical sign of the Hamaker constant correlates with the contrasting behaviors. Collectively, these results have implications for theoretical descriptions of adsorption layer growth and crossover behavior, for measurements of complete wetting temperatures, and for practical applications.
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7,655 members
Liu-Qin Yang
  • Department of Psychology
Dara Shifrer
  • Department of Sociology
Erin E. Shortlidge
  • Department of Biology
David Harold Peyton
  • Department of Chemistry
Andrew Fountain
  • Department of Geology
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