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  1. Free, publicly-accessible full text available September 1, 2024
  2. Collective behavioural plasticity allows ant colonies to adjust to changing conditions. The red harvester ant (Pogonomyrmex barbatus), a desert seed-eating species, regulates foraging activity in response to water stress. Foraging ants lose water to evaporation. Reducing foraging activity in dry conditions sacrifices food intake but conserves water. Within a year, some colonies tend to reduce foraging on dry days while others do not. We examined whether these differences among colonies in collective behavioural plasticity persist from year to year. Colonies live 20–30 years with a single queen who produces successive cohorts of workers which live only a year. The humidity level at which all colonies tend to reduce foraging varies from year to year. Longitudinal observations of 95 colonies over 5 years between 2016 and 2021 showed that differences among colonies, in how they regulate foraging activity in response to day-to-day changes in humidity, persist across years. Approximately 40% of colonies consistently reduced foraging activity, year after year, on days with low daily maximum relative humidity; approximately 20% of colonies never did, foraging as much or more on dry days as on humid days. This variation among colonies may allow evolutionary rescue from drought due to climate change.

     
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    Free, publicly-accessible full text available September 1, 2024
  3. Abstract

    Viable nature-based climate solutions (NbCS) are needed to achieve climate goals expressed in international agreements like the Paris Accord. Many NbCS pathways have strong scientific foundations and can deliver meaningful climate benefits but effective mitigation is undermined by pathways with less scientific certainty. Here we couple an extensive literature review with an expert elicitation on 43 pathways and find that at present the most used pathways, such as tropical forest conservation, have a solid scientific basis for mitigation. However, the experts suggested that some pathways, many with carbon credit eligibility and market activity, remain uncertain in terms of their climate mitigation efficacy. Sources of uncertainty include incomplete GHG measurement and accounting. We recommend focusing on resolving those uncertainties before broadly scaling implementation of those pathways in quantitative emission or sequestration mitigation plans. If appropriate, those pathways should be supported for their cobenefits, such as biodiversity and food security.

     
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    Free, publicly-accessible full text available April 1, 2025
  4. Funded by the National Science Foundation (NSF) Racial Equity in STEM Education Program, this project aims to deeply interrogate the influence and pervasiveness of Whiteness in engineering culture. While there has been substantial research into the masculinity of engineering, Whiteness has received far less attention. We claim the centrality of Whiteness in engineering curricula informs the culture, climate, and discourse of engineering education, leading to an exclusionary culture within engineering as reflected by the lack of diversity and lower retention of students and faculty of color, and contributes to systemic barriers negatively impacting racial equity. Moving towards racial equity in engineering education requires a fundamental shift in thinking in two important ways: 1) we must reframe how we think about underserved populations from minority to minoritized by a dominant discourse, and 2) to begin to dismantle the impacts of Whiteness, we must first make this barrier visible. In the first year of this project, the diverse team of PIs began to explore scripts of Whiteness in engineering education by conducting a collaborative autoethnography through documenting and analyzing their own experiences facing, enacting, and challenging scripts of Whiteness in engineering spaces. A collaborative autoethnography (CAE) takes a collaborative approach to the process of critical self reflection and can be conducted in many forms, such as such as collecting personal memory data (e.g., journaling), interviewing each other, facilitating intentional dialogue, or observing each other (e.g., in the classroom). CAE is not a linear process, but requires an ongoing dialogue (conversations, negotiations, or even arguments) between researcher team members over a long period (at least months, if not years). Our diverse viewpoints and years-long experience working together facilitated rich conversations that let us interrogate the ways in which Whiteness reveals its form differently depending on one’s positionality. In the later years of the project, we will create a faculty development program intended to help engineering faculty develop their critical consciousness and begin to decenter Whiteness from their ways of thinking and discourses (i.e., beliefs, attitudes, value systems, actions, etc.) so they can begin to critically think about promoting and enacting practices that move engineering education toward racial equity. Although the pathway to critical consciousness is not linear, it is a one-way street; once faculty begin to see the systemic barriers (such as those created by scripts of Whiteness) around them, there is no going back. In the long term, we hope to lay the groundwork for recognizing, interrogating, and eventually dismantling forces of systemic oppression in engineering higher education. 
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    Free, publicly-accessible full text available June 25, 2024
  5. Free, publicly-accessible full text available June 1, 2024
  6. Does emphasizing the role of people in engineering influence the memorability of engineering content? This study is part of a larger project through which our team developed a new undergraduate energy course to better reflect students’ cultures and lived experiences through asset-based pedagogies to help students develop a sociotechnical mindset in engineering problem solving. In this study, students in the class were invited to participate in semi-structured interviews (n=5) to explore our effectiveness in helping them develop a sociotechnical mindset around energy issues and conceptualize engineering as a sociotechnical endeavor. This study focuses on an activity during the interview where the participants were asked to sort a variety of images associated with class learning experiences along a spectrum of least to most memorable. Emergent themes from students’ responses revolved around learning experiences that included global perspectives and emphasized a “who” (i.e., whose problems, who is impacted by engineering, and what type of engineers the students will choose to become) as the most memorable. Our results indicate that students found the sociotechnical aspects of the course more memorable than the traditional canonical engineering content. These findings suggest that framing engineering content as sociotechnical can be one strategy to increase student engagement, increase memorability of lessons, and help students to think more deeply about their own goals as future engineers. 
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    Free, publicly-accessible full text available July 6, 2024
  7. As watersheds are complex systems that are difficult to directly study, the streams that drain them are often sampled to search for watershed “signals.” These signals include the presence and/or abundance of isotopes, types of sediment, organisms (including pathogens), chemical compounds associated with ephemeral biogeochemical processes or anthropogenic impacts, and so on. Just like watersheds can send signals via the streams that drain from them, we present a conceptual analysis that suggests plant canopies (equally complex and hard-to-study systems) may send similar signals via the precipitation that drains down their stems (stemflow). For large, tall, hard-to-access tree canopies, this portion of precipitation may be modest, often <2%; however, stemflow waters, like stream waters, scour a large drainage network which may allow stemflow to pick up various signals from various processes within and surrounding canopies. This paper discusses some of the signals that the canopy environment may impart to stemflow and their relevance to our understanding of vegetated ecosystems. Being a conceptual analysis, some examples have been observed; most are hypothetical. These include signals from on-canopy biogeochemical processes, seasonal epi-faunal activities, pathogenic impacts, and the physiological activities of the canopy itself. Given stemflow's currently limited empirical hydrological, ecological and biogeochemical relevance to date (mostly due to its modest fraction in most forest water cycles), future work on the possible “signals in stemflow” may also motivate more natural scientists and, perhaps some applied researchers, to rigorously monitor this oft-ignored water flux. 
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  8. In the spring of 2021, the University of San Diego’s Department of Integrated Engineering taught the course, “Integrated Approach to Energy”, the second offering of a new required course, to nine second-year engineering students. The sociotechnical course covered modern energy concepts, with an emphasis on renewable energies and sustainability, and it exposed the students to other ways of being, knowing, and doing that deviated from the dominant masculine Western White colonial discourse. Following the course completion, we interviewed five students by using a semistructured protocol to explore how they perceived of and communicated about engineers and engineering. We sought to identify the takeaways from their course exposure to sustainability and the sociotechnical paradigm, which were central to the course. The findings suggest that the students were beginning to form sociotechnical descriptions, and that they were still developing their understanding and perceptions of engineers and engineering. Moreover, we observed that they were still wrestling with how best to integrate sustainability into those perceptions. There was an a-la-carte feel to the students’ conceptualizations of sustainability as it related to engineering, as in, “you can ‘do’ sustainability with engineering, but do not have to”. We argue that engineering students likely need these pedagogical paradigms (sociotechnical engineering and sustainability) woven through the entirety of their engineering courses if they are to fully accept and integrate them into their own constructs about engineers and engineering. 
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  9. null (Ed.)
    Engineers are increasingly called on to develop sustainable solutions to complex problems. Within engineering, however, economic and environmental aspects of sustainability are often prioritized over social ones. This paper describes how efficiency and sustainability were conceptualized and interrelated by students in a newly developed second-year undergraduate engineering course, An Integrated Approach to Energy. This course took a sociotechnical approach and emphasized modern energy concepts (e.g., renewable energy), current issues (e.g., climate change), and local and personal contexts (e.g., connecting to students’ lived experiences). Analyses of student work and semi-structured interview data were used to explore how students conceptualized sustainability and efficiency. We found that in this cohort (n = 17) students often approached sustainability through a lens of efficiency, believing that if economic and environmental resources were prioritized and optimized, sustainability would be achieved. By exploring sustainability and efficiency together, we examined how dominant discourses that privilege technical over social aspects in engineering can be replicated within an energy context. 
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