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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133 Cs NMR Study of the Ferroelectric and Antiferroelectric Transitions in CsH 2 PO 4
(1991-05-01) Schuele, Paul J.; Schmidt, V. Hugo
Pressure and temperature effects on the one dimensional (1D) and higher-dimensionality correlations associated with the ferroelectric (FE) and antiferroelectric (AFE) phase transitions in cesium dihydrogen phosphate were studied using 133Cs nuclear magnetic resonance at 6.5 MHz. The spin-latticerelaxation time T1 was measured at temperatures down to the FE Curie point TC at pressures of 1 bar and at 1.5 and 3.0 kbar, down to the triple point Tt = 124.6 K at 3.3 kbar, and down to the AFE Neel point TN at 3.6 kbar. Far from the transition T1 decreases exponentially with decreasing temperature due to 1D fluctuations associated with the Jb interactions in disordered hydrogen-bonded chains running along the b axis. As temperature is decreased further, T1 decreases linearly as the JC interaction between hydrogen-bonded chains in b-c planes becomes important. From these results the pressure dependences of Jb, JC and the interplanar interaction Ja were calculated. At 3.3 kbar Ja changes sign, so the stacking of ordered planes becomes AFE rather than FE. At pressures above about 9 kbar, where the interaction JC extrapolates to zero, a new AFE phase is predicted in which each b-axis chain is oriented AFE with respect to nearest neighbors in both the a and c directions.
17O NQR Study of the Antiferroelectric Phase Transition in TlH2PO4
(1988) Seliger, J.; Zagar, V.; Blinc, Robert; Schmidt, V. Hugo
The temperature dependence of the 1 7O NQR spectra in TlH2PO4 has been measured using a proton‐1 7 O nuclear quadrupole double resonance technique. The results show that the protons in the short one‐dimensionally linked O1–H1‐‐O1 and O2–H2‐‐O2hydrogen bonds are moving between two equilibrium sites above T c and freeze into one of the off‐center sites below T c . The protons in the asymmetric O3–H3‐‐O4hydrogen bonds are static and ordered above and below T c .
18β-Glycyrrhetinic Acid Induces Metabolic Changes and Reduces Staphylococcus aureus Bacterial Cell-to-Cell Interactions
(MDPI AG, 2022-06) Weaver, Alan J.; Borgogna, Timothy R.; O’Shea-Stone, Galen; Peters, Tami R.; Copié, Valérie; Voyich, Jovanka; Teintze, Martin
The rise in bacterial resistance to common antibiotics has raised an increased need for alternative treatment strategies. The natural antibacterial product, 18β-glycyrrhetinic acid (GRA) has shown efficacy against community-associated methicillin-resistant Staphylococcus aureus (MRSA), although its interactions against planktonic and biofilm modes of growth remain poorly understood. This investigation utilized biochemical and metabolic approaches to further elucidate the effects of GRA on MRSA. Prolonged exposure of planktonic MRSA cell cultures to GRA resulted in increased production of staphyloxanthin, a pigment known to exhibit antioxidant and membrane-stabilizing functions. Then, 1D 1H NMR analyses of intracellular metabolite extracts from MRSA treated with GRA revealed significant changes in intracellular polar metabolite profiles, including increased levels of succinate and citrate, and significant reductions in several amino acids, including branch chain amino acids. These changes reflect the MRSA response to GRA exposure, including potentially altering its membrane composition, which consumes branched chain amino acids and leads to significant energy expenditure. Although GRA itself had no significant effect of biofilm viability, it seems to be an effective biofilm disruptor. This may be related to interference with cell–cell aggregation, as treatment of planktonic MRSA cultures with GRA leads to a significant reduction in micro-aggregation. The dispersive nature of GRA on MRSA biofilms may prove valuable for treatment of such infections and could be used to increase susceptibility to complementary antibiotic therapeutics.
The 1972 Montana State Constitution--its provision for Montana Indians : a promise unfulfilled
(Montana State University - Bozeman, 1981) Eschler, Leonard Edward
A 1975 catalog of alternate and free secondary schools in Montana
(Montana State University - Bozeman, 1975) Lithander, Sherry Lee Miller
1982–2010 Trends of Light Use Efficiency and Inherent Water Use Efficiency in African vegetation: Sensitivity to Climate and Atmospheric CO2 Concentrations
(MDPI, 2014) Traore, Abdoul Khadre; Ciais, Philippe; Vuichard, Nicolas; McBean, Natasha; Dardel, Cecile; Poulter, Benjamin; Piao, Shilong; Fisher, Joshua; Viovy, Nicolas; Jung, Martin; Myneni, Ranga B.
Light and water use by vegetation at the ecosystem level, are key components for understanding the carbon and water cycles particularly in regions with high climate variability and dry climates such as Africa. The objective of this study is to examine recent trends over the last 30 years in Light Use Efficiency (LUE) and inherent Water Use Efficiency (iWUE*) for the major biomes of Africa, including their sensitivities to climate and CO2. LUE and iWUE* trends are analyzed using a combination of NOAA-AVHRR NDVI3g and fAPAR3g, and a data-driven model of monthly evapotranspiration and Gross Primary Productivity (based on flux tower measurements and remote sensing fAPAR, yet with no flux tower data in Africa) and the ORCHIDEE (ORganizing Carbon and Hydrology In Dynamic EcosystEms) process-based land surface model driven by variable CO2 and two different gridded climate fields. The iWUE* data product increases by 10%–20% per decade during the 1982–2010 period over the northern savannas (due to positive trend of vegetation productivity) and the central African forest (due to positive trend of vapor pressure deficit). In contrast to the iWUE*, the LUE trends are not statistically significant. The process-based model simulations only show a positive linear trend in iWUE* and LUE over the central African forest. Additionally, factorial model simulations were conducted to attribute trends in iWUE and LUE to climate change and rising CO2 concentrations. We found that the increase of atmospheric CO2 by 52.8 ppm during the period of study explains 30%–50% of the increase in iWUE* and >90% of the LUE trend over the central African forest. The modeled iWUE* trend exhibits a high sensitivity to the climate forcing and environmental conditions, whereas the LUE trend has a smaller sensitivity to the selected climate forcing.
1H NMR based metabolic profiling distinguishes the differential impact of capture techniques on wild bighorn sheep
(Springer Science and Business Media LLC, 2021-05) O’Shea-Stone, Galen; Lambert, Rachelle; Tripet, Brian; Berardinelli, James; Thomson, Jennifer; Copié, Valérie; Garrott, Robert
Environmental metabolomics has the potential to facilitate the establishment of a new suite of tools for assessing the physiological status of important wildlife species. A first step in developing such tools is to evaluate the impacts of various capture techniques on metabolic profiles as capture is necessary to obtain the biological samples required for assays. This study employed 1H nuclear magnetic resonance (NMR)-based metabolite profiling of 562 blood serum samples from wild bighorn sheep to identify characteristic molecular serum makers of three capture techniques (dart, dropnet, and helicopter-based captures) to inform future sampling protocols for metabolomics studies, and to provide insights into the physiological impacts of capture. We found that different capture techniques induce distinct changes in amino acid serum profiles, the urea cycle, and glycolysis, and attribute the differences in metabolic patterns to differences in physical activity and stress caused by the different capture methods. These results suggest that when designing experiments involving the capture of wild animals, it may be prudent to employ a single capture technique to reduce confounding factors. Our results also supports administration of tranquilizers as soon as animals are restrained to mitigate short-term physiological and metabolic responses when using pursuit and physical restraint capture techniques.
2017 Montana Climate Assessment: Stakeholder driven, science informed
(Montana Institute on Ecosystems, 2017-09) Whitlock, Cathy; Cross, Wyatt F.; Maxwell, Bruce D.; Silverman, Nick; Wade, Alisa A.
The Montana Climate Assessment (MCA) is an effort to synthesize, evaluate, and share credible and relevant scientific information about climate change in Montana with the citizens of the State. The motivation for the MCA arose from citizens and organizations in Montana who have expressed interest in receiving timely and pertinent information about climate change, including information about historical variability, past trends, and projections of future impacts as they relate to topics of economic concern.This first assessment reports on climate trends and their consequences for three of Montana’s vital sectors: water, forests, and agriculture. We consider the MCA to be a sustained effort. We plan to regularly incorporate new scientific information, cover other topics important to the people of Montana, and address the needs of the state.
75As nuclear quadrupole resonance in weakly substitutionally disordered Rb1‑x(NH4)xH2AsO4
(1994-07-11) Papantopoulos, G.; Papavassiliou, G.; Milia, F.; Schmidt, V. Hugo; Drumheller, John E.; Pinto, Nicholas J.; Blinc, Robert; Zalar, B.
A Deeper Look into eFEDS AGN Candidates in Dwarf Galaxies with Chandra
(American Astronomical Society, 2024-10) Sanchez, Adonis A.; Reines, Amy E.; Bogdán, Ákos; Kraft, Ralph
The ability to accurately discern active massive black holes (BHs) in nearby dwarf galaxies is paramount to understanding the origins and processes of "seed" BHs in the early Universe. We present Chandra X-ray Observatory observations of a sample of three local dwarf galaxies (M* ≤ 3 × 109M⊙, z ≤ 0.15) previously identified as candidates for hosting active galactic nuclei (AGN). The galaxies were selected from the NASA-Sloan Atlas with spatially coincident X-ray detections in the eROSITA Final Equatorial Depth Survey. Our new Chandra data reveal three X-ray point sources in two of the target galaxies with luminosities between log(L2−10 keV [erg s−1]) = 39.1 and 40.4. Our results support the presence of an AGN in these two galaxies and an ultraluminous X-ray source (ULX) in one of them. For the AGNs, we estimate BH masses of MBH ∼ 105−6M⊙ and Eddington ratios on the order of ∼10−3.
A dependable distance estimator to black hole low-mass X-ray binaries
(Oxford University Press, 2024-03) Abdulghani, Y.; Lohfink, A. M.; Chauhan, J.
Black Hole Low Mass X-ray Binaries (BH-LMXBs) are excellent observational laboratories for studying many open questions in accretion physics. However, determining the physical properties of BH-LMXBs necessitates knowing their distances. With the increased discovery rate of BH-LMXBs, many canonical methods cannot produce accurate distance estimates at the desired pace. In this study, we develop a versatile statistical framework to obtain robust distance estimates soon after discovery. Our framework builds on previous methods where the soft spectral state and the soft-to-hard spectral state transitions, typically present in an outbursting BH-LMXB, are used to place constraints on mass and distance. We further develop the traditional framework by incorporating general relativistic corrections, accounting for spectral/physical parameter uncertainties, and employing assumptions grounded in current theoretical and observational knowledge. We tested our framework by analyzing a sample of 50 BH-LMXB sources using X-ray spectral data from the Swift/XRT, MAXI/GSC, and RXTE/PCA missions. By modeling their spectra, we applied our framework to 26 sources from the 50. Comparison of our estimated distances to previous distance estimates indicates that our findings are dependable and in agreement with the accurate estimates obtained through parallax and H i absorption methods. Investigating the accuracy of our constraints, we have found that estimates obtained using both the soft and transition spectral information have a median uncertainty (1σ) of 20%, while estimates obtained using only the soft spectral state spectrum have a median uncertainty (1σ) of around 50%. Furthermore, we have found no instrument-specific biases.
A framework to link climate change, food security, and migration: unpacking the agricultural pathway
(Springer Science and Business Media LLC, 2024-03) Tuholske, Cascade; Di Landro, Maria Agustina; Anderson, Weston; van Duijne, Robbin Jan; de Sherbinin, Alex
Researchers have long hypothesized linkages between climate change, food security, and migration in low- and middle-income countries (LMICs). One such hypothesis is the “agricultural pathway,” which postulates that negative climate change impacts on food production harm livelihoods, which triggers rural out-migration, internally or abroad. Migration is thus an adaptation to cope with the impacts of climate change and bolster livelihoods. Recent evidence suggests that the agriculture pathway is a plausible mechanism to explain climate-related migration. But direct causal connections from climate impacts on food production to livelihood loss to rural out-migration have yet to be fully established. To guide future research on the climate-food-migration nexus, we present a conceptual framework that outlines the components and linkages underpinning the agricultural pathway in LMICs. We build on established environmental-migration conceptual frameworks that have informed empirical research and deepened our understanding of complex human-environmental systems. First, we provide an overview of the conceptual framework and its connection to the agricultural pathway hypothesis in the climate mobility literature. We then outline the primary components and linkages of the conceptual framework as they pertain to LMIC contexts, highlighting current research gaps and challenges relating to the agricultural pathway. Last, we discuss possible future research directions for the climate-food-migration nexus. By highlighting the complex, multiscale, interconnected linkages that underpin the agricultural pathway, our framework unpacks the multiple causal connections that currently lie hidden in the agricultural pathway hypothesis.
A Latitudinal Gradient of Reference Genomes
(Wiley, 2024-10) Linck, Ethan B.; Cadena, Carlos Daniel
Global inequality rooted in legacies of colonialism and uneven development can lead to systematic biases in scientific knowledge. In ecology and evolutionary biology, findings, funding and research effort are disproportionately concentrated at high latitudes, while biological diversity is concentrated at low latitudes. This discrepancy may have a particular influence in fields like phylogeography, molecular ecology and conservation genetics, where the rise of genomics has increased the cost and technical expertise required to apply state-of-the-art methods. Here, we ask whether a fundamental biogeographic pattern—the latitudinal gradient of species richness in tetrapods—is reflected in the available reference genomes, an important data resource for various applications of molecular tools for biodiversity research and conservation. We also ask whether sequencing approaches differ between the Global South and Global North, reviewing the last 5 years of conservation genetics research in four leading journals. We find that extant reference genomes are scarce relative to species richness at low latitudes and that reduced representation and whole-genome sequencing are disproportionately applied to taxa in the Global North. We conclude with recommendations to close this gap and improve international collaborations in biodiversity genomics.
A Luminous X-Ray Active Galactic Nucleus in the Dwarf–Dwarf Galaxy Merger RGG 66
(American Astronomical Society, 2024-10) Kimbrell, Seth J.; Reines, Amy E.
We present the discovery of a luminous X-ray active galactic nucleus (AGN) in the dwarf galaxy merger RGG 66. The black hole is predicted to have a mass of M BH ∼ 10 5.4 M ⊙ and to be radiating close to its Eddington limit ( L bol / L Edd ∼ 0.75). The AGN in RGG 66 is notable both for its presence in a late-stage dwarf–dwarf merger and for its luminosity of L 2–10 keV = 10 42.2 erg s −1 , which is among the most powerful AGNs known in nearby dwarf galaxies. The X-ray spectrum has a best-fit photon index of Γ = 2.4 and an intrinsic absorption of N H ∼ 10 21 cm −2 . These results come from a follow-up Chandra X-ray Observatory study of four irregular/disturbed dwarf galaxies with evidence for hosting AGNs based on optical spectroscopy. The remaining three dwarf galaxies do not have detectable X-ray sources with upper limits of L 2–10 keV ≲ 10 40 erg s −1 . Taken at face value, our results on RGG 66 suggest that mergers may trigger the most luminous of AGNs in the dwarf galaxy regime, just as they are suspected to do in more massive galaxy mergers.
A Radio Study of Persistent Radio Sources in Nearby Dwarf Galaxies: Implications for Fast Radio Bursts
(American Astronomical Society, 2024-09) Dong, Y.; Eftekhari, T.; Fong, W.; Bhandari, S.; Berger, E.; Ould-Boukattine, O.S.; Hessels, J. W. T.; Sridhar, N.; Reines, A.; Margalit, B.; Darling, J.; Gordon, A. C.; Greene, J. E.; Kilpatrick, C. D.; Marcote, B.; Metzger, B. D.; Nimmo, K.; Nugent, A. E.; Paragi, Z.; Williams, P. K. G.
We present 1–12 GHz Karl G. Jansky Very Large Array observations of nine off-nuclear persistent radio sources (PRSs) in nearby (z ≲ 0.055) dwarf galaxies, along with high-resolution European VLBI Network observations for one of them at 1.7 GHz. We explore the plausibility that these PRSs are associated with fast radio burst (FRB) sources by examining their properties—physical sizes, host-normalized offsets, spectral energy distributions (SEDs), radio luminosities, and light curves—and compare them to those of the PRSs associated with FRB 20121102A and FRB 20190520B, two known active galactic nuclei (AGN), and one likely AGN in our sample with comparable data, as well as other radio transients exhibiting characteristics analogous to FRB-PRSs. We identify a single source in our sample, J1136+2643, as the most promising FRB-PRS, based on its compact physical size and host-normalized offset. We further identify two sources, J0019+1507 and J0909+5655, with physical sizes comparable to FRB-PRSs, but which exhibit large offsets and flat spectral indices potentially indicative of a background AGN origin. We test the viability of neutron star wind nebula and hypernebula models for J1136+2643 and find that the physical size, luminosity, and SED of J1136+2643 are broadly consistent with these models. Finally, we discuss the alternative interpretation that the radio sources are instead powered by accreting massive black holes, and we outline future prospects and follow-up observations for differentiating between these scenarios.
A-site strontium doping effects on structure, magnetic, and photovoltaic properties of (Bi 1-x Sr x )FeO 3-δ multiferroic ceramics
(2015) Tu, Chi-Shun; Xu, Zhe-Rui; Schmidt, V. Hugo; Chan, T.-S.; Chien, R. R.; Son, H.
Raman spectroscopy, X-ray diffraction (XRD), magnetization hysteresis loop, synchrotron X-ray absorption spectroscopy, and photovoltaic effects have been measured in (Bi1−xSrx)FeO3−δ (BFO100xSr) ceramics for x=0.0, 0.05, 0.10, and 0.15. Raman spectra and XRD reveal a rhombohedral R3c structure in all compounds. A-site Sr2+ doping increases fluctuations in cation-site occupancy and causes broadening in Raman modes. BFO15Sr exhibits a strong ferromagnetic feature due to reduction of FeOFe bond angle evidenced by the extended synchrotron X-ray absorption fine structure. The heterostructure of indium tin oxide (ITO) film/(Bi1−xSrx)FeO3−δ ceramic/Au film exhibit clear photovoltaic (PV) responses under blue illumination of λ=405 nm. The maximal power-conversion efficiency and external quantum efficiency in ITO/BFO5Sr/Au are about 0.004% and 0.2%, respectively. A model based on optically excited charges in the depletion region between ITO and (Bi1−xSrx)FeO3−δ can well describe open-circuit voltage and short-circuit current as a function of illumination intensity.
A-site strontium doping effects on structure, magnetic, and photovoltaic properties of (Bi1−xSrx)FeO3−δ multiferroic ceramics
(2015-03) Tu, Chi-Shun; Xu, Zhe-Rui; Schmidt, V. Hugo; Chan, Ting-Shan; Chien, R.R.; Son, Hyungbin
Raman spectroscopy, X-ray diffraction (XRD), magnetization hysteresis loop, synchrotron X-ray absorption spectroscopy, and photovoltaic effects have been measured in (Bi1−xSrx)FeO3−δ (BFO100xSr) ceramics for x=0.0, 0.05, 0.10, and 0.15. Raman spectra and XRD reveal a rhombohedral R3c structure in all compounds. A-site Sr2+ doping increases fluctuations in cation-site occupancy and causes broadening in Raman modes. BFO15Sr exhibits a strong ferromagnetic feature due to reduction of Fesingle bondOsingle bondFe bond angle evidenced by the extended synchrotron X-ray absorption fine structure. The heterostructure of indium tin oxide (ITO) film/(Bi1−xSrx)FeO3−δ ceramic/Au film exhibit clear photovoltaic (PV) responses under blue illumination of λ=405 nm. The maximal power-conversion efficiency and external quantum efficiency in ITO/BFO5Sr/Au are about 0.004% and 0.2%, respectively. A model based on optically excited charges in the depletion region between ITO and (Bi1−xSrx)FeO3−δ can well describe open-circuit voltage and short-circuit current as a function of illumination intensity.
Ability to benefit : a credible basis for admissions to tribally controlled colleges
(Montana State University - Bozeman, College of Education, Health & Human Development, 1991) Boham, Sandra Lee
Absarog-Issawua (from the land of the Crow Indians)
(Montana State University - Bozeman, 1970) Toineeta, Joy Yellowtail
"This is an original piece of research into the Crow Indian uses of native plants and animals for food and medicinal, as well as other purposes. Incorporated into the manuscript are introductory legends or incidents surrounding or accompanying the recipes."
Absent autonomy: Relational competence and gendered paths to faculty self-determination in the promotion and tenure process
(2018-09) Skewes, Monica C.; Shanahan, Elizabeth A.; Smith, Jessi L.; Honea, Joy C.; Belou, Rebecca M.; Rushing, Sara; Intemann, Kristen; Handley, Ian M.
This research examines ways in which men and women university faculty sought self-determination in the promotion and tenure (P&T) process. Self-Determination Theory (SDT; Deci & Ryan, 2012) research tends to view autonomy as the central factor in self-determination, taking priority over other psychological needs of relatedness and competence. The P&T process occurs within a context that inherently limits autonomy, providing a unique opportunity to examine experiences of relatedness and competence when autonomy is constrained. We used a qualitative research strategy with a matched case study design to explore how individuals experience the constructs of SDT (i.e., autonomy, competence, and relatedness) within the P&T process. Our project focuses on faculty in science, technology, engineering, and mathematics (STEM) departments undergoing P&T review at one university. Women faculty in STEM were compared with men faculty at the same rank and in similar departments concurrently going through P&T review. Findings showed that men reported experiencing self-determination via informational competence whereas women approached self-determination through relational competence. Creating a level playing field for faculty navigating the P&T process requires being attuned to different paths to self-determination, fostering relationships between faculty, and clarifying policies and procedures.