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Evaluating the effects of beaver-related restoration on aquatic ecosystems Outcomes and risks of beaver reintroductions
Full text linkReversing or stemming declines in ecosystem function and biodiversity are main areas of focus for restoration ecology and conservation biology. Conservation and restoration ecologists have increasingly shifted towards restoring ecosystem processes rather than specific community compositions or habitat conditions. Rewilding is a promising strategy for restoring ecosystem processes at the landscape scale through reintroductions of species that regulate ecosystem processes. Beavers (Castor canadensis and Castor fiber) are well studied ecosystem engineers that have profound impacts on biotic and abiotic components of ecosystems. Beaver-related restoration (BRR), including beaver reintroductions and mimicry structures, is increasingly used to restore ecosystem processes and increase biodiversity in freshwater systems of the United States and Europe; however, implementation has outpaced research on aspects of the rewilding and ecosystem restoration process. In this dissertation, I focus on aspects of rewilding reintroductions and restoration ecology using BRR as a study system. Specifically, my research focuses on developing tools to assess population establishment, assessing disease risks associated with animal reintroductions, and synthesizing how ecosystem engineer reintroductions impact ecosystem processes and biodiversity across ecological contexts.For my first project, I evaluated the efficacy and spatial inference associated with environmental DNA (eDNA) techniques for detecting reintroduced beaver presence in natural wetland and stream systems. I conducted eDNA sampling paired with radio-tracking of translocated beavers to elucidate spatial patterns of site use, eDNA detection probability, and eDNA quantity. I find that eDNA techniques detect beaver rapidly over long distances and reliably detect upstream beavers. These findings suggest that eDNA methods could be a valuable tool for rapid inventory and assessment of beaver occupancy and highlight important implications for using eDNA to monitor other semi-aquatic mammal species that share similar life histories.For my second project, I evaluated whether one important fungal pathogen, Batrachochytrium dendrobatidis (Bd), maintains viability on beaver pelts and assess effects of neutralization treatments on Bd viability. I conducted a laboratory experiment by inoculating small sections of beaver pelt with high concentrations of live Bd zoospores, incubating them to observe viability and growth, and applying realistic neutralization treatments to pelt sections to evaluate the effects of treatment on Bd. I find the first evidence that Bd can adhere to and maintain viability on mammal hairs up to 21 days after initial exposure and provide evidence that simple treatments may be effective for reducing the risk of transmitting Bd during beaver relocation. My findings provide evidence that co-dispersal of external pathogens may be an important process to consider during animal reintroductions and mitigating these risks may be important for protecting recipient ecosystems from unintentional pathogen introductions.For my third project, I conducted a comprehensive literature review focused on beaver-related restoration’s (BRR) influence on habitat and biodiversity attributes that confer climate resilience across western North America. I used 161 sources, assigned confidence scores for specific outcomes, and identified climatic and hydrogeomorphic contexts where BRR may be most impactful at building climate resiliency. I find substantial evidence that BRR increases climate resiliency of stream and riparian ecosystems by reducing summer water temperatures, increasing water storage, and enhancing floodplain connectivity. However, benefits are only likely to accrue under certain climatic and hydrogeomorphic conditions, and I highlight the deficit of peer-reviewed literature at the spatial and temporal scope necessary bridge our understanding of the aspirational potential and the realized benefits of BRR. My findings suggest that rewilding and ecological restoration efforts require a deeper understanding of the ecological contexts that produce desired outcomes and recommend that future research needs to consider appropriate spatial and temporal scales
Examining Infant Asymmetry Across an Extended Negative Emotion Eliciting Task Considering Parenting Interaction and Temperamental Moderators
Full text linkFrontal electroencephalograph (EEG) asymmetry has emerged as a prominent neurophysiological temperament correlate, with relative left activation reflecting approach/positive affectivity and relative right activation indicative of avoidance emotions/motivation. EEG asymmetry during emotion-eliciting tasks has not been sufficiently examined, and this study considered changes in infant frontal alpha asymmetry during a distress-eliciting task relative to baseline, consistent with the capability model. This project had three primary aims: (1) model temperament effects related to changes in asymmetry across an emotion-eliciting task; (2) model effects of mother-infant interaction quality related to changes in asymmetry across trials of this task; and (3) quantify the extent to which frontal alpha asymmetry growth parameters across an emotion-eliciting task predict infant task completion – i.e., whether or not all of the trials of the task had been completed, or the task had to be cut short due to excessive distress. To address the first two aims/hypotheses, a latent growth model was estimated, considering infant EEG asymmetry across the five distinct trials of the Still-Face Paradigm, with the parent-child interaction and temperament factors used as predictors of intercept and growth parameters in turn. For the third aim/hypothesis, another latent model was examined, determining if frontal asymmetry growth parameters predict an infant’s ability to complete the task. Initial analysis supported a linear model as the best fitting parameter, and subsequently were computed with the interaction and temperament factors. Overall hypotheses were not supported, indicating that neither infants’ temperament nor their interactions with parents significantly impacted their neurophysiology at the start of the SFP task. Results and future directions are discussed in full
METHODS DEVELOPMENT FOR THE ANALYSIS OF BIOMOLECULES IN CHALLENGING PLANT AND MICROBIAL MATRICES
Full text linkReliable and reproducible method development and data analysis are crucial for biotechnological research. Focusing on two studies, we optimized the analytical workflows for gene expression and metabolite quantitation across distinct biological systems. One study focused on the quantitation of specific isoforms ferredoxin (Fd) and ferredoxin-NADP+ reductase (FNR) in peppermint (Mentha × piperita L.) across various peppermint organs and cell types, both of which have been determined to have essential roles in the reductive steps in the 2C-methyl-D-erythritol 4-phosphate (MEP) pathway of terpenoid biosynthesis in glandular trichomes (GTs). We recognized that a single reference gene approach for normalization was inadequate and determined that the utilization of a GPU-accelerated tool, NormiRazor, to validate a three-gene normalization strategy for reference gene stability was necessary. Based on the results from the expression patterns of each isoform, we determined that Fd II was highly expressed in GTs, with moderate expression in the roots, compared to the other isoform, Fd III, which had significantly less expression in the roots and the GTs. These results suggest that the high transcript abundance of Fd II is responsible for the flux through the MEP pathway rather than the biochemical differences in enzymes encoded by the Fd II and Fd III gene transcripts. The second study centered around genetically modified yeast strains (Saccharomyces cerevisiae Y55-1034 and Saccharomyces boulardii (SB)2022) from the AMES NASA BioNutrients-1 project for the biomanufacturing of essential carotenoids, β-carotene and zeaxanthin, for astronauts during long-term spaceflight. Due to the sensitive nature of carotenoids, which degrade due to temperature, light, and oxygen, robust methods for carotenoid extraction, as well as standard curve generation, were developed. First, stability analysis of carotenoids, specifically β-carotene, revealed that after short-term storage of samples, degradation of the carotenoid is observed, quantified by an increase in cleavage product peak areas and a decrease of the β-carotene peak area (one exhibiting a 51% decrease). Similarly, the method for carotenoid extraction optimization was crucial for ensuring complete recovery of the target compound. Adding a mechanical agitator significantly improved yeast cell lysis and β-carotene yield in the same experimental groups. In one case, the utilization of a mechanical agitator recovered enough β-carotene (95.5 μg/ g culture biomass) for HPLC instrument detection; compared to extraction without, there was no β-carotene detected. The standard curves were tightly correlated around their best-fit lines, validating the method for the development of reproducible and accurate standard curves. Together, these studies revolve around the critical need for method development to enable the accurate quantitation of biological molecules in challenging plant and microbial systems
IMPACT OF ANTICOAGULANT RODENTICIDES ON JUVENILE COHO SALMON (ONCORHYNCHUS KISUTCH) ASSESSING LETHAL & SUBLETHAL EFFECTS
Full text linkWhole island rodent eradications in the Aleutian Islands rely on aerial baiting with anticoagulant rodenticides (ARs) to protect native seabirds. While aerial applications aim for precision, pellets inevitably enter aquatic environments, raising concerns about non-target impacts on salmonids. However, toxicity data for aquatic species are limited. To address this gap, we used coho salmon (Oncorhynchus kisutch) to generate dose-response curves via intraperitoneal (IP) injections in corn oil, estimating 96-hour LD50 values of 80.1 µg/g (95% CI: 65.8–94.4 µg/g) for brodifacoum and 60.7 µg/g (95% CI: 55.9–65.5 µg/g) for diphacinone. IP injections deliver chemicals in oil for rapid uptake, but acetone is sometimes needed in the oil to maintain higher concentrations of ARs in solution. We found that the presence of acetone in injection stock significantly reduced the toxicity of diphacinone but not brodifacoum. The acetone may impact diphacinone bioavailability or metabolism, whereas brodifacoum is known to be poorly metabolized prior to elimination. Tissue analysis supported a difference in metabolism. In moribund fish dosed with 85 µg/g of brodifacoum, liver and muscle concentrations averaged (SD) 105.6 (31.4) µg/g and 21.5 (3.4) µg/g, respectively, with no significant reduction in surviving fish sampled at 96 hours. In contrast, diphacinone concentrations in moribund fish (100 µg/g dose) started at 176.5 (73.6) µg/g in the liver and 22.7 (5.1) µg/g in the muscle but were 0.899 (0.299) µg/g and 0.063 (0.053) µg/g, respectively, in survivors at 96 hours. Clotting time was used as a sublethal endpoint and was measured over time after administering a single sublethal dose. When exposed to 55.0 µg/g (LD14) of brodifacoum, coho had significantly longer clotting times at 72 and 96 hours post-injection. Clotting times returned to baseline by 120 hours post-injection. We did not observe significantly increased clotting times within 144 hours after dosing coho with 50 µg/g (LD2) of diphacinone. This suggests that diphacinone may affect coho through a different mode of action
UNDERSTANDING CLIMATE CHANGE MITIGATION AND ADAPTATION POLICY SUPPORT IN THE UNITED STATES OF AMERICA
Full text linkA discrepancy exists between public concern for climate change and support for policy solutions for climate change. Understanding why there is a discrepancy between concern and support is important to reduce that discrepancy. Much of this discrepancy has been attributed to sharp political divisions in support of climate policies. However, climate change policies are not one-dimensional. Only a few studies have examined differences in support in a way that distinguishes mitigation from adaptation policies, with a small number suggesting less political division over adaptation policies. This dissertation aims to fill this gap in the literature by exploring the latent structure of public support for climate change policies and understanding the nuanced variations in partisan support across different types of climate change policies.This dissertation utilizes survey data from voting-age U.S. residents to expand understanding of the multiple dimensions of public support for climate change policies. It is organized in a three-study format, each constituting a distinct paper, with each paper being suitable for independent submission to academic journals. The first study uses exploratory and confirmatory factor analysis to uncover the underlying structural dimensions of climate change policy support. The findings show that support for climate change policies is better understood as a multidimensional construct that distinguishes mitigation from adaptation policies. Researchers should avoid overly generalized discussions of climate change policies and should rather clearly specify whether they are referring to climate mitigation or adaptation policies in their research.The second study analyzes how political identity shapes public support for climate mitigation and adaptation policies. A comprehensive investigation of support for mitigation and adaptation policies reveals nuanced differences among Republicans in their support for adaptation versus mitigation. While Democrats show similar levels of support for mitigation and adaptation policies, Republicans show higher levels of support for adaptation than mitigation policies. These findings offer critical insights for crafting more successful policy approaches, which take advantage of the knowledge that climate adaptation policies are less polarized.The third study investigates a belief known as the inverted quarantine impulse, which maintains that individuals can personally shield themselves from climate harm. It examines how this impulse interacts with political identity to influence climate policy support preferences. The findings suggest that the inverted quarantine impulse may drive greater support for adaptation over mitigation policies. An interaction effect was found for Republicans who have higher levels of the inverted quarantine impulse, showing that they also have higher levels of support for climate mitigation policies
Locating Woodstock
Full text linkIn the annals of American cultural memory, the music festival that occurred between the 15th and 18th of August, 1969 is referred to as Woodstock. For individuals who access this memory, they understand this event to be Woodstock and the performances and moments that made it a cultural touchstone to be representative of Woodstock, the Woodstock generation, and Woodstock Nation. While Woodstock has percolated as a naturalized element of the American cultural landscape, this project begins by departing from that convention and centering the historical reality that the original name of Woodstock was, in fact, the Aquarian Exposition. By using Walter Benjamin’s method of brushing against the grain of history and Lawrence Grossberg’s radical contextual method, conjunctural analysis, this project locates Woodstock by identifying the process through which the original event, the Aquarian Exposition, became known as Woodstock and investigates the implications of that process. Locating Woodstock using this method occurs along three axes. First, this project examines the history of music festivals in the United States. In paying particular attention to folk music festivals from the middle of the 19th century through the middle of the 20th century, this project argues that music festivals are a crucial site of national, racial, and subject formation. Next, this project assembles a useful history of the Aquarian Exposition to destabilize Woodstock’s position in American cultural memory as a climactic and inevitable moment. The Aquarian Exposition, to varying degrees, came about as the result of a series of accidents, few of which have been processed into Woodstock. Finally, this project provides close readings of three texts, all of which were published between 1969 and 1979, that were crucial to the development of what this project terms the Woodstock archive. In discussing these texts, this project concludes its argument that what is referred to as Woodstock was not actually an event, but an assemblage of visual symbology and memory
EXPLORING THE DEVELOPMENT OF PRODUCTIVE STEM IDENTITY IN UNDERREPRESENTED MINORITIZED STUDENTS IN AN APPLIED MATHEMATICS CLASS CONTEXT
Full text linkThis mixed methods research study analyzed the development of student STEM identity in underrepresented/minoritized (URM) high school mathematics students by effective identity-building strategies implemented in the context of integrated STEM instruction (Civil, 2016). As a teacher-researcher, I identified student changes in three traits associated with productive STEM identity: agency, belongingness, and self-efficacy (Cobb, et al., 2009; Brickhouse & Potter, 2001; Carlone & Johnson, 2007). Using a funds of knowledge approach, I re-envisioned STEM learning as a cultural process that embraced relevant and authentic contexts provided by my students (Civil, 2016). Over the course of a school year, I collected and analyzed data from a demographically diverse class including surveys, student reflections, student interviews, artifacts, and journal entries. Results showed that embedding student-informed STEM activities in a mathematics course can promote productive STEM identity development in URM students. My study concluded that my instructional approach and architecture contributed to the productive development of student STEM identity and positively affected student engagement with and awareness of mathematical concepts in authentic applications
“MEDIA WAS THE ONLY WAY I COULD FIGURE OUT WHO I WAS” EXPLORING FICTIONAL ENTERTAINMENT’S ROLE IN IDENTITY AND COMMUNITY FORMATION AMONG RURAL LGBTQ+ YOUNG ADULTS
Full text linkIndividuals living in rural areas of the United States are widely considered to be more isolated compared to those in more populous urban cities. Minority groups in rural areas, such as the LGBTQ+ community, though, are all the more isolated than heteronormative community members. While previous media effects research has examined how online resources, such as chat rooms and blogs, can enhance the lives and access to queer information of rural LGBTQ+ individuals, little is known about the impacts that engaging in fictional entertainment film and television has on this subpopulation. With a theoretical framework of pertinent media effects research, the present study made use of qualitative in-depth semi-structured interviews with rural LGBTQ+ young adults to examine how fictional entertainment film and television helped such individuals build their queer identities and find queer community while living in rural areas of the United States. This research has broader implications in understanding the well-being of rural queer individuals and ways in which community can be built in the streaming age
INVESTIGATING THE PERFORMANCE OF CONNECTIONS IN CROSS-LAMINATED TIMBER (CLT) PANELS CONSTRUCTED FROM THERMALLY MODIFIED WESTERN HEMLOCK LUMBER
Full text linkCross-laminated timber (CLT) has emerged as a revolutionary and sustainable construction material, offering lower greenhouse gas emissions, ease of assembly, and affordability. However, their vulnerability to moisture, rot, and dimensional instability restricts their wider use in structural applications. While thermally modified (TM) CLT has demonstrated improved dimensional stability and enhanced resistance to moisture in prior research, the mechanical performance of connections in TM CLT remains unexplored. This lack of understanding prevents the full realization of the potential of TM CLT in modern construction. This study evaluates the mechanical behavior of connections in TM Western Hemlock (WH) 3-ply CLT treated at 180ׄ°C and compares it with unmodified (UM) CLT, focusing on the shear performance through component-level and system-level experimental tests.The component-level test involved a series of experimental tests performed on screws and TM and UM WH lumber and CLT panels, to evaluate the lateral resistance performance of connections in TM CLT panels and compare it with UM CLT panels. The study examined four different types of screws in single-fastener and multiple-fastener configurations, comparing the TM and UM WH CLT with analysis guided by the National Design Specification (NDS, 2018) yield limit equations to predict connection behavior across all potential failure modes theoretically. The lateral resistance test uncovered variations in the failure mechanisms governed by fastener geometry, revealing critical interactions between wood bearing capacity and screw performance. The systematic analysis between experimental test results and NDS predictions validated the applicability of conventional yield theory to TM CLT connections.The system-level connections test evaluated the in-plane shear performance of wall-to-floor assemblies using three commercially available angle brackets under monotonic and cyclic loading. The performance of connections was assessed in terms of strength and failure modes. Results showed a critical relationship between the connection geometry, load distribution, and the bearing capacity of CLT. Moreover, the results demonstrated that although TM lumber has lower dowel bearing capacity than UM lumber, TM CLT connections can achieve comparable performance to UM CLT connections with appropriate fastener selection and connection detailing.This study confirms that TM CLT panels made up of TM WH can achieve comparable connection capacity to both UM and conventional CLT. This outcome lays the groundwork for future research aimed at addressing the performance gaps in uplift, out-of-plane loads, and combined stress interactions, which will lead to greater confidence regarding the use of TM CLT in structural contexts. It should be noted that more experimental tests on larger sample groups and with different species and thermal modification processes are required to acquire greater confidence in the results, as time and material for this research were limited
3D-printed biocompatible hollow microneedle-based electrochemical sensor for wireless glucose monitoring
Full text linkWearable electrochemical sensors have aroused tremendous attention due to their great potential for in situ and continuous assessment for glucose monitoring. Conventional fingerstick test is the easiest and most efficient method for glucose evaluation, but invasive and painful. Here we introduce a wearable and user-friendly microneedle-based electrochemical sensor, fabricated via resin 3D printing and integration of a single-atom nanozyme-modified electrode, offering excellent biocompatibility, high sensitivity and superior selectivity for glucose monitoring. This minimally invasive electrochemical sensor demonstrates the capability to extract artificial interstitial fluid using biocompatible hollow microneedles and a finger-activated pump, enabling continuous monitoring of dynamic glucose concentration changes. This electrochemical sensor exhibits remarkable sensitivity and exceptional selectivity, with a linear range of 0.1 μM to 50 mM and a limit of detection of 0.059 μM, attributed to the incorporation of single-atom nanozymes with peroxidase-like enzymatic activity. The glucose concentration data are wirelessly transmitted to a mobile app in real time, offering user-friendly access and facilitating remote monitoring. The described electrochemical sensor presents the possibilities for point-of-care health monitoring applications. https://doi.org/10.26434/chemrxiv-2025-gv8xt ORCID: https://orcid.org/0000-0002-3138-0275 Content not peer-reviewed by ChemRxiv. License: CC BY 4.0