College of Letters & Science
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The College of Letters and Science, the largest center for learning, teaching and research at Montana State University, offers students an excellent liberal arts and sciences education in nearly 50 majors, 25 minors and over 25 graduate degrees within the four areas of the humanities, natural sciences, mathematics and social sciences.
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Item Training community members to deliver an intervention for substance use disorder: Overcoming implementation barriers in American Indian communities(Elsevier BV, 2024-10) Skewes, Monica C.; Gonzalez, Vivian M.; Stix, AmyIntroduction. Although American Indian and Alaska Native (AI/AN) people have high rates of abstinence from alcohol and other drugs, there also is evidence of greater rates of substance use disorders (SUDs) in Native communities. Health disparities associated with substance use are compounded by inadequate access to evidence-based treatments (EBTs). Lack of mental health providers is one notable barrier to EBT implementation in rural AI reservation communities. Our Indigenous Recovery Planning (IRP) intervention merges cultural lessons and culturally adapted relapse prevention strategies to facilitate SUD recovery in the reservation environment. One key implementation strategy is training non-specialist community-based facilitators to deliver IRP, thereby increasing its acceptability and sustainability. This manuscript reports the facilitator training, supervision, and fidelity monitoring procedures used in our ongoing clinical trial of IRP. Method. The study recruited four AI non-specialist providers from the community to serve as IRP facilitators. Initial training involved an introductory motivational interviewing workshop followed by a 2-day workshop in the IRP curriculum. Then we conducted an open trial of the 6-week intervention with weekly supervision meetings as part of the facilitator training process. During the open trial we also assessed participant and facilitator receptivity to the IRP intervention and pilot tested our fidelity monitoring protocol. Results. The initial training workshops provided facilitators with information they needed to understand the rationale behind IRP and determine whether the facilitator role was a good fit; however, additional training and supervision during the open trial was needed to ensure proper treatment delivery. Although participant and facilitator feedback ratings were positive, the open trial helped us identify revisions needed to improve our approach to facilitator training, supervision, and fidelity monitoring. We revised these procedures, and also developed a protocol to train new facilitators who join the study midstream. Conclusion. The open trial was an important aspect of the facilitator training process and helped our team identify several areas of improvement. Our approach to training, supervising, and monitoring community member facilitators may serve as an example of how to overcome one barrier to implementing evidence-based SUD treatments in rural reservation communities with few mental health professionals.Item Political identity and risk politics: Evidence from a pandemic(Wiley, 2024-10) Raile, Eric D.; Haines, Pavielle; Raile, Amber N. W.; Shanahan, Elizabeth A.; Parker, David C. W.The way political identity serves as a foundation for political polarization in the United States permits elites to extend conflict rapidly to new issue areas. Further, the types of cognitive mechanisms and shortcuts used in the politically polarized information environment are similar to some of those used in risk perception. Consequently, political elites may easily create partisan risk positions, largely through politically focused social amplification of risk. The COVID-19 pandemic provided a natural experiment for testing predictions about such risk politics. We asked questions about pandemic-related views, behaviors, and policies at the outset of the pandemic in April 2020 and again in September 2020 via public opinion surveys. Our data and analyses focus primarily on a single state, with some analysis extended to four states. We begin by demonstrating strong linkages between political partisan identification on the one hand and support for co-partisan elites, use of partisan information sources, and support for co-partisan policies on the other hand. We then find evidence that pandemic risk positions correspond with partisan information sources and find support for a mechanism involving partisan-tinted evaluation of elite cues. Partisan risk positions quickly became part of the larger polarized structure of political support and views. Finally, our evidence shows on the balance that partisan risk positions related to the pandemic coalesced and strengthened over time. Overall, while self-identified Democrats consistently viewed the coronavirus as the primary threat, self-identified Republicans quickly pivoted toward threats to their freedoms and to the economy.Item Two-photon absorption reveals low-energy excited states of a 2,5,8-triamino-heptazine chromophore(SPIE, 2024-06) Stark, Charles W.; Arak, Johanna; Trummal, Aleksander; Uudsemaa, Merle; Sildoja, Meelis-Mait; Pahapill, Juri; Rebane, AleksTriamino-heptazines (TAH's) comprise the fundamental building blocks of graphitic carbon nitride, an alluring material with promising applications in optoelectronics. However, the core D3h molecular symmetry enforces a forbidden lowest-energy excited singlet state, making it a challenge to characterize via conventional spectroscopy. Here, we measure oneand two-photon absorption spectra of an acidic form of triamino-heptazine, 3H-TAH, and use reversible acid/base titration to further probe the symmetry of the low-energy transitions in aqueous solution, which suggests the molecular base structure is dimelem. Two-photon absorption reveals two distinct low-energy transitions in acidic conditions, both of which are one-photon forbidden. The lowest energy state additionally becomes one-photon allowed in basic conditions. Spectroscopic changes can be described according to chromophore symmetry switching, with C3h, D3h, or Cs point group symmetry in respective acidic, neutral, or basic environments.Item Effects of lignin syringyl to guaiacyl ratio on cottonwood biochar adsorbent properties and performance(Springer Science and Business Media LLC, 2024-08) Muretta, Julie E.; Uriarte, Jade; Compton, Dalton; LaDouceur, Richard; Kirtley, John; Prieto-Centurion, DarioLignin syringyl to guaiacyl ratio (S/G) has long been suspected to have measurable impacts on biochar formation, but these effects are challenging to observe in biochars formed from whole biomass. When the model bioenergy feedstock Populus trichocarpa (cottonwood), with predictable lignin macromolecular structure tied to genetic variation, is used as feedstock for biochar production, these effects become visible. In this work, two P. trichocarpa variants having lignin S/G of 1.67 and 3.88 were ground and pyrolyzed at 700 °C. Water-demineralization of feedstock was used to simultaneously evaluate any synergistic influences of S/G and naturally-occurring potassium on biochar physicochemical properties and performance. The strongest effects of lignin S/G were observed on specific surface area (SBET) and oxygen-content, with S/G of 1.67 improving SBET by 11% and S/G of 3.88 increasing total oxygen content in demineralized biochars. Functional performance was evaluated by breakthrough testing in 1% NH3. Breakthrough times for biochars were nearly double that of a highly microporous activated carbon reference material, and biochar with S/G of 3.88 had 10% longer breakthrough time than its lower S/G corollary. Results support a combination of pore structure and oxygen-functionalities in controlling ammonia breakthrough for biochar.Item Child Incarceration and Maternal Alcohol Use: Disentangling Within- and Between-Person Processes(SAGE Publications, 2024-01) Greene, Kaylin; Warner, CodyHaving a child incarcerated can take a toll on the physical, psychological, and financial well-being of mothers. These factors could, in turn, affect behavioral outcomes of mothers, such as alcohol use patterns. Some mothers might drink to cope with the experience of having a child incarcerated, but others may reduce alcohol use for various reasons. Given these uncertainties, the authors examined the association between child incarceration and maternal alcohol consumption (i.e., any use, frequency, quantity, and binge drinking). Eight waves of nationally representative data from the National Longitudinal Survey of Youth 1979 cohort were linked with the National Longitudinal Survey Children and Young Adults (n = 3,837 mothers; 678 had children incarcerated). Multilevel generalized linear regression models showed that compared with mothers with no child incarceration, mothers of ever-incarcerated children were more likely to binge drink and consume more drinks when drinking (between-person effects). In contrast, following child incarceration, women consumed alcohol less frequently and were less likely to binge drink than they were prior to experiencing child incarceration (within-person effects). Additional research should focus on mechanisms that explain these opposing associations to identify protective factors and institutional supports for women whose children have been incarcerated.Item Insights into the indigenous-managed landscape in southeast Australia during the Holocene(Springer Science and Business Media LLC, 2023-04) Adesanya Adeleye, Matthew; Graeme Haberle, Simon; Hopf, Felicitas; Harris, Stephen; McWethy, David BurchUnderstanding the long-term interactions between people and the ecosystem in which they live is vital for informing present-day ecosystem management plans. The use of pollen data for palaeoecological reconstructions is often limited by the low taxonomic resolution of pollen, which often reduces the detail of reconstructions of human influence on past vegetation. This is true for Australia where Myrtaceae, particularly Eucalyptus species, dominate the landscape, but their pollen is difficult to differentiate. We present a pollen record with high taxonomic resolution of Myrtaceae pollen from the Bass Strait area of southeast Australia, focusing on the period of major human occupation there during the Late Glacial transition. These results were compared to records of hydrology, fire, sediment deposition, herbivore abundance and human occupation. We found that Indigenous burning practices promoted open, subgenus Monocalyptus Eucalyptus woodland at the expense of dense subgenus Symphomyrtus Eucalyptus forest. Previous studies have shown the need for management of the vegetation of southeast Australia guided by Indigenous people, to promote ecosystem resilience and reduce the risk of wildfires. Our results reveal that in addition to reducing wildfires, cultural burning by Indigenous people has the potential to promote the diversity of ecosystems and habitats.Item Increased whitebark pine (Pinus albicaulis) growth and defense under a warmer and regionally drier climate(Frontiers Media SA, 2023-03) Kichas, Nickolas E.; Pederson, Gregory T.; Hood, Sharon M.; Everett, Richard G.; McWethy, David B.Introduction: Tree defense characteristics play a crucial role in modulating conifer bark beetle interactions, and there is a growing body of literature investigating factors mediating tree growth and resin-based defenses in conifers. A subset of studies have looked at relationships between tree growth, resin duct morphology and climate; however, these studies are almost exclusively from lower-elevation, moisture limited systems. The relationship between resin ducts and climate in higher-elevation, energy-limited ecosystems is currently poorly understood. Methods: In this study, we: (1) evaluated the relationship between biological trends in tree growth, resin duct anatomy, and climatic variability and (2) determined if tree growth and resin duct morphology of whitebark pine, a high-elevation conifer of management concern, is constrained by climate and/or regional drought conditions. Results: We found that high-elevation whitebark pine trees growing in an energy-limited system experienced increased growth and defense under warmer and regionally drier conditions, with climate variables explaining a substantive proportion of variation (∼20–31%) in tree diameter growth and resin duct anatomy. Discussion: Our results suggest that whitebark pine growth and defense was historically limited by short growing seasons in high-elevation environments; however, this relationship may change in the future with prolonged warming conditions.Item Assessing changes in global fire regimes(Springer Science and Business Media LLC, 2024-02) Sara Sayedi, Sayedeh et al.; McWethy, DavidBackground. The global human footprint has fundamentally altered wildfire regimes, creating serious consequences for human health, biodiversity, and climate. However, it remains difficult to project how long-term interactions among land use, management, and climate change will affect fire behavior, representing a key knowledge gap for sustainable management. We used expert assessment to combine opinions about past and future fire regimes from 99 wildfire researchers. We asked for quantitative and qualitative assessments of the frequency, type, and implications of fire regime change from the beginning of the Holocene through the year 2300. Results. Respondents indicated some direct human influence on wildfire since at least ~ 12,000 years BP, though natural climate variability remained the dominant driver of fire regime change until around 5,000 years BP, for most study regions. Responses suggested a ten-fold increase in the frequency of fire regime change during the last 250 years compared with the rest of the Holocene, corresponding first with the intensification and extensification of land use and later with anthropogenic climate change. Looking to the future, fire regimes were predicted to intensify, with increases in frequency, severity, and size in all biomes except grassland ecosystems. Fire regimes showed different climate sensitivities across biomes, but the likelihood of fire regime change increased with higher warming scenarios for all biomes. Biodiversity, carbon storage, and other ecosystem services were predicted to decrease for most biomes under higher emission scenarios. We present recommendations for adaptation and mitigation under emerging fire regimes, while recognizing that management options are constrained under higher emission scenarios. Conclusion. The influence of humans on wildfire regimes has increased over the last two centuries. The perspective gained from past fires should be considered in land and fire management strategies, but novel fire behavior is likely given the unprecedented human disruption of plant communities, climate, and other factors. Future fire regimes are likely to degrade key ecosystem services, unless climate change is aggressively mitigated. Expert assessment complements empirical data and modeling, providing a broader perspective of fire science to inform decision making and future research priorities.Item PEARLS: Discovery of Point-source Features within Galaxies in the North Ecliptic Pole Time Domain Field(American Astronomical Society, 2024-10) Ortiz III, Rafael et al.; Gim, Hansung B.The first public 0.9–4.4 μm NIRCam images of the North Ecliptic Pole Time Domain Field uncovered galaxies displaying point-source features in their cores as seen in the longer-wavelength filters. We visually identified a sample of 66 galaxies (∼1 galaxy arcmin–2) with pointlike cores and have modeled their two-dimensional light profiles with GalFit, identifying 16 galactic nuclei with measurable point-source components. GalFit suggests that the visual sample is a mix of both compact stellar bulge and point-source galaxy cores. This core classification is complemented by spectral energy distribution modeling to infer the sample's active galactic nucleus (AGN) and host-galaxy parameters. For galaxies with measurable point-source components, the median fractional AGN contribution to their 0.1–30.0 μm flux is 0.44, and 14/16 are color-classified AGN. We conclude that near-infrared point-source galaxy cores are signatures of AGN. In addition, we define an automated sample-selection criterion to identify these point-source features. This criterion can be used in other extant and future NIRCam images to streamline the search for galaxies with unresolved IR-luminous AGN. The James Webb Space Telescope's superb angular resolution and sensitivity at infrared wavelengths are resurrecting the morphological identification of AGN.Item A 2000-year record of fecal biomarkers reveals past herbivore presence and impacts in a catchment in northern Yellowstone National Park, USA(Public Library of Science, 2024-10) Wendt, John A .F.; Argiriadis, Elena; Whitlock, Cathy; Bortolini, Mara; Battistel, Dario; McWethy, David B.Molecular biomarkers preserved in lake sediments are increasingly used to develop records of past organism occurrence. When linked with traditional paleoecological methods, analysis of molecular biomarkers can yield new insights into the roles of herbivores and other animals in long-term ecosystem dynamics. We sought to determine whether fecal steroids in lake sediments could be used to reconstruct past ungulate use and dominant taxa in a small catchment in northern Yellowstone National Park. To do so, we characterized the fecal steroid profiles of a selection of North American ungulates historically present in the Yellowstone region (bison, elk, moose, mule deer, and pronghorn) and compared them with those of sediments from a small lake in the Yellowstone Northern Range. Analysis of a set of fecal steroids from herbivore dung (Δ5-sterols, 5α-stanols, 5β-stanols, epi5β-stanols, stanones, and bile acids) differentiated moose, pronghorn, and mule deer, whereas bison and elk were partially differentiated. Our results show that bison and/or elk were the primary ungulates in the watershed over the past c. 2300 years. Fecal steroid influxes reached historically unprecedented levels during the early and middle 20th century, possibly indicating high local use by ungulates. Comparison of fecal steroid influxes with pollen and diatom data suggests that elevated ungulate presence may have contributed to decreased forage taxa (Poaceae, Artemisia, and Salix), relative to long-term averages, and possibly increased lake production. Our results reflect past change within a single watershed, and extending this approach to a network of sites could provide much-needed information on past herbivore communities, use, and environmental influences in Yellowstone National Park and elsewhere.