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Item Assessing the use of native rhizobia to improve nitrogen fixation under abiotic stress(Wiley, 2024-09) Loya, Jesus; Subramanian, Sen; Kalil, Audrey; Keene, Clair; Sanyal, Debankur; Eberly, Jed; Graham, ChristopherBiological nitrogen fixation by rhizobia bacteria plays a pivotal role in sustainable agriculture by converting atmospheric nitrogen into a form that plants can assimilate, thereby reducing the need for synthetic fertilizers. This process can be dramatically reduced by various abiotic stressors. Native rhizobia strains, which are naturally occurring, may be better adapted to the local soil and climatic conditions, making them more resilient to stress factors such as drought, salinity, temperature extremes, and pH variations compared to commercial strains that may have been developed in and for different environments. This study aimed to compare the efficacy of native rhizobia species with a commercial inoculant and uninoculated controls in maintaining nitrogen fixation under induced stress by delayed planting in field peas over two growing seasons (2021 and 2022) in central South Dakota. Our findings indicate that native rhizobia, while not outperforming the commercial inoculant, demonstrated competitive nitrogen fixation capacities. Overall, total nitrogen fixation was not statistically different between a commercial inoculant and native rhizobia formulations. Planting date emerged as a significant factor influencing nitrogen fixation, with later planting substantially reducing overall effectiveness. These results highlight the potential of native rhizobia as an alternative to commercial inoculants and underscore the need for increased screening throughput and improved methods to assess rhizobia efficacy and nodule competition in field settings.Item Changes in African lion demography and population growth with increased protection in a large, prey-depleted ecosystem(Wiley, 2024-12) Creel, Scott; Becker, Matthew S.; Goodheart, Ben; Kusler, Anna; Banda, Kachama; Vinks, Milan; Sun, Catherine; Dart, Chase; Matsushima, Stephi; Kabwe, Ruth; Donald, Will; Zyambo, Luka; Indala, Peter; Kaluka, Adrian; Chifunte, Clive; Reid, CraigLarge carnivores such as the lion are declining across Africa, in part because their large herbivore prey is declining. There is consensus that increased protection from prey depletion will be necessary to reverse the decline of lion populations, but few studies have tested whether increased protection is sufficient to reverse the decline, particularly in the large, open ecosystems where most lions remain. Here, we used an integrated population model to test whether lion demography and population dynamics were measurably improved by increased protection. We used data from monitoring of 358 individuals from 2013 to 2021 in the Greater Kafue Ecosystem, where prior research showed that lions were strongly limited by prey depletion, but protection increased in several well-defined areas beginning in 2018. In some other areas, protection decreased. In areas with high protection, lion fecundity was 29% higher, and mean annual apparent survival (φ) was 8.3% higher (with a minimum difference of 6.0% for prime-aged adult females and a maximum difference of 11.9% for sub-adult males). These demographic benefits combined to produce likely population growth in areas with high protection (φ= 1.085, 90% CI = 0.97, 1.21), despite likely population decline in areas with low protection (φ = 0.970, 90% CI = 0.88, 1.07). For the ecosystem as a whole, population size remained relatively constant at a moderate density of 3.74 (±0.49 SD) to 4.13 (±0.52 SD) lions/100 km2. With the growth observed in areas with high protection, the expected doubling time was 10 years. Despite this, recovery at the scale of the entire ecosystem is likely to be slow without increased protection; the current growth rate would require 50 years to double. Our results demonstrate that increased protection is likely to improve the reproduction and population growth rate of lions at a large scale within an unfenced ecosystem that has been greatly affected by poaching.Item Inferred attractiveness gravity-based models for estimating realized access at rural hospitals(Informa UK Limited, 2024-09) Harris, Sean; McGarvey, Ronald G.; Thorsen, Andreas; Thorsen, MaggieOperating obstetric units in rural America is financially challenging in part due to low birth volume. Birth volume at a hospital decreases when birthers bypass it to go to a farther hospital. Beyond financial considerations, it is important from a healthcare equity perspective for hospitals to know whether certain subgroups of birthers avoid utilizing the hospital’s services. This can better inform resource allocation decisions targeting those subgroups. In this paper, we use a nonlinear programming optimization model, inferred attractiveness gravity-based model (GBM), to estimate realized access to obstetric care at hospitals in Montana. We compare three variations of GBM and benchmark our results to a regression-based conditional logit model. Results indicate that hospital attractiveness varies across the level of obstetric care provided and depends on the subgroup of birthers considered. While all GBMs produced smaller errors for hospitals with higher birth volumes, our novel variant was more accurate for low-volume hospitals. Bootstrapping analyses and resolving the models for population subgroups indicated large variations in hospital attractiveness. Research findings contribute to new knowledge about equity in access to obstetric care, the importance of considering population heterogeneity in GBMs, and the benefit of using hospital demand-based thresholds for GBMs in rural settings.Item Response of indicator species to changes in food web and ocean dynamics of the Ross Sea, Antarctica(Cambridge University Press, 2024-09) Ainley, David G.; Morandini, Virginia; Salas, Leo; Rottella, Jay; Barton, Kerry; Lyver, Phil O'B.; Goetz, Kimberly T.; Larue, Michelle; Foster-Dyer, Rose; Parkinson, Claire L.; Arrigo, Kevin R.; Van Dijken, Gert; Beltran, Roxanne S.; Kim, Stacy; Brooks, Cassandra; Kooyman, Gerald; Ponganis, Paul J.; Shanhun, Fiona; Anderson, Dean P.Most of the Ross Sea has been designated a marine protected area (MPA), proposed ‘to protect ecosystem structure and function’. To assess effectiveness, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) selected Adélie (Pygoscelis adeliae) and emperor (Aptenodytes forsteri) penguins, Weddell seals (Leptonychotes weddellii) and Antarctic toothfish (Dissostichus mawsoni) as ecosystem change ‘indicator species’. Stable for decades, penguin and seal populations increased during 1998–2018 to surpass historical levels, indicating that change in ecosystem structure and function is underway. We review historical impacts to population trends, decadal datasets of ocean climate and fishing pressure on toothfish. Statistical modelling for Adélie penguins and Weddell seals indicates that variability in climate factors and cumulative extraction of adult toothfish may explain these trends. These mesopredators, and adult toothfish, all prey heavily on Antarctic silverfish (Pleuragramma antarcticum). Toothfish removal may be altering intraguild predation dynamics, leading to competitive release of silverfish and contributing to penguin and seal population changes. Despite decades of ocean/weather change, increases in indicator species numbers around Ross Island only began once the toothfish fishery commenced. The rational-use, ecosystem-based viewpoint promoted by CCAMLR regarding toothfish management needs re-evaluation, including in the context of the Ross Sea Region MPA.Item Effect of surface roughness on the microbiologically influenced corrosion (MIC) of copper 101(Frontiers Media SA, 2024-12) Archarjee, Amit; Keskin, Yagmur; Peyton, Brent M.; Fields, Matthew W.; Amendola, RobertaThe effect of varying surface roughness on microbiologically influenced corrosion by a model sulfate reducing bacterium Oleidesulfovibrio alaskensis G20 culture on copper 101 coupons was investigated using microscopic, spectroscopic and surface characterization techniques. After 7-day of anoxic exposure abundant biodeposits consisting of sessile cells and copper sulfide minerals were found and pitting attack was observed upon their removal. Results showed that the distribution and thickness of the biodeposits as well as the pitting severity were affected by the varying surface roughness. A direct relationship between surface roughness and microbial activity was not observed. However, a statistically significant reduction in the corrosion rate was recorded when the surface roughness was decreased from ∼2.71 μm to ∼0.006 μm.Item Generalized measures of population synchrony(Elsevier BV, 2024-12) Motta, Francis C.; McGoff, Kevin; Cummins, Breschine; Haase, Steven B.Synchronized behavior among individuals, broadly defined, is a ubiquitous feature of populations. Understanding mechanisms of (de)synchronization demands meaningful, interpretable, computable quantifications of synchrony, relevant to measurements that can be made of complex, dynamic populations. Despite the importance to analyzing and modeling populations, existing notions of synchrony often lack rigorous definitions, may be specialized to a particular experimental system and/or measurement, or may have undesirable properties that limit their utility. Here we introduce a notion of synchrony for populations of individuals occupying a compact metric space that depends on the Fréchet variance of the distribution of individuals across the space. We establish several fundamental and desirable mathematical properties of our proposed measure of synchrony, including continuity and invariance to metric scaling. We establish a general approximation result that controls the disparity between synchrony in the true space and the synchrony observed through a discretization of state space, as may occur when observable states are limited by measurement constraints. We develop efficient algorithms to compute synchrony for distributions in a variety of state spaces, including all finite state spaces and empirical distributions on the circle, and provide accessible implementations in an open-source Python module. To demonstrate the usefulness of the synchrony measure in biological applications, we investigate several biologically relevant models of mechanisms that can alter the dynamics of population synchrony over time, and reanalyze published experimental and model data concerning the dynamics of the intraerythrocytic developmental cycles of Plasmodium parasites. We anticipate that the rigorous definition of population synchrony and the mathematical and biological results presented here will be broadly useful in analyzing and modeling populations in a variety of contexts.Item Nest Defense Behavior of Suburban and Rural Red-shouldered Hawks(The Raptor Research Foundation, Inc., 2024-11) Dykstra, Cheryl R.; Dykstra, Laura R.; Simon, Melinda M.; Hays, Jeffrey L.; Wegman, Ann R.Urban and suburban raptors live in close proximity to humans, and some species defend their nests and young vigorously, even diving at or striking humans walking on the ground. Such raptors may be more defensive of their nests than rural birds. We investigated (1) whether Red-shouldered Hawk (Buteo lineatus) nest defense behavior differs between suburban and rural birds, (2) whether any environmental conditions are associated with aggressive nest defense, and (3) whether nest defense behavior is associated with reproductive rate. First, we used an experimental walk-up protocol to approach nests with incubating or brooding Red-shouldered Hawks at suburban and rural sites, and we scored the hawk's response to our approach. We measured environmental variables (nest height, distance to the nearest road and nearest house, and habitat proportions within 500 m of the nest) and determined reproductive rate. Second, we used our historical database to retrospectively classify hawks as most aggressive, moderately aggressive, or not aggressive, and we measured the same environmental variables at their nest sites. We found that most birds at both suburban and rural study areas responded to our experimental approach with minimal nest defense, though suburban birds responded with higher levels of nest defense. Environmental variables were unrelated to nest defense intensity in the experimental study. For the retrospective study in the suburban area, nest height was the only environmental factor distinguishing aggressive hawks from non-aggressive ones; aggressive nest defensive behavior was associated with lower nests. Reproductive rate was unrelated to nest defense behavior in both studies. Knowing which environmental factors may contribute to more aggressive behavior may help researchers, managers, and residents better understand bird behavior and predict the circumstances under which problems might develop, particularly in urban/suburban environments.Item Adiposity throughout Adulthood and Risk of Young-Onset Breast Cancer Tumor Subtypes in the Young Women’s Health History Study(American Association for Cancer Research, 2024-10) Marcus Post, Lydia; Pathak, Dorothy R.; Hamilton, Ann S.; Hirko, Kelly A.; Houang, Richard T.; Guseman, Emily H.; Sanfelippo, Dan; Carnegie, Nicole Bohme; Olson, L. Karl; Schwartz, Ann G.; Velie, Ellen M.Background: The role of adult adiposity in young-onset breast cancer (YOBC) subtype risk is not well understood. Methods: In this population-based case (n = 1812)–control (n = 1,381) study of invasive YOBC (ages <50 years), cases were identified from the Los Angeles County and Metropolitan Detroit Surveillance, Epidemiology, and End Results registries, 2010 to 2015. Area-based, frequency-matched controls were sampled from the 2010 Census. General adiposity [body mass index (BMI)] and central adiposity (waist circumference and waist-to-height ratio) across adulthood and covariates were collected from in-person interviews and measurements. ORs and 95% confidence intervals (CI) for adiposity and YOBC tumor subtypes [i.e., luminal A, luminal B, HER2+, and triple negative (TN)] were calculated, overall and by parity, using multivariable weighted logistic regression. Results: Obese young adult BMI was inversely associated with luminal A YOBC (OR = 0.35, 95% CI, 0.16–0.79); other subtype associations were nonsignificant. Similarly, adult overweight and obese BMIs were inversely associated with luminal A (OR = 0.66, 95% CI, 0.48–0.91 and OR = 0.59, 95% CI, 0.46–0.87, respectively), but not other subtypes. Conversely, larger waist circumference was associated with higher odds of luminal B and TN YOBC (OR = 1.48, 95% CI, 1.01–2.15 and OR = 2.48, 95% CI, 1.52–3.88, respectively), but not other subtypes (with similar results for weight-to-height ratio); highest odds were among parous women. Conclusions: Findings show greater general adult adiposity is associated with reduced odds of luminal A YOBC, whereas greater central adiposity is associated with increased odds of luminal B and TN YOBC, particularly among parous women. Impact: Additional studies of central adiposity and YOBC subtype risk, especially incorporating pregnancy history, are warranted.Item DIISC-IV. DIISCovery of Anomalously Low Metallicity H ii Regions in NGC 99: Indirect Evidence of Gas Inflows(American Astronomical Society, 2024-11) Olvera, Alejandro J.; Borthakur, Sanchayeeta; Padave, Mansi; Heckman, Timothy M.; Gim, Hansung B.; Koplitz, Brad; Dupuis, Christopher M.; Momjian, Emmanuel; Jansen, Rolf A.As a part of the Deciphering the Interplay between the Interstellar medium, Stars, and the Circumgalactic medium (DIISC) survey, we investigate indirect evidence of gas inflow into the disk of the galaxy NGC 99. We combine optical spectra from the Binospec spectrograph on the MMT telescope with optical imaging data from the Vatican Advanced Technology Telescope, radio H i 21 cm emission images from the NSF Karl G. Jansky's Very Large Array, and UV spectroscopy from the Cosmic Origins Spectrograph on the Hubble Space Telescope. We measure emission lines (Hα, Hβ, [O iii]λ5007, [N ii]λ6583, and [S ii]λ6717, 31) in 26 H ii regions scattered about the galaxy and estimate a radial metallicity gradient of −0.017 dex kpc−1 using the N2 metallicity indicator. Two regions in the sample exhibit an anomalously low metallicity (ALM) of 12 + log(O/H) = 8.36 dex, which is ∼0.16 dex lower than other regions at that galactocentric radius. They also show a high difference between their H i and Hα line of sight velocities on the order of 35 km s−1. Chemical evolution modeling indicates gas accretion as the cause of the ALM regions. We find evidence for corotation between the interstellar medium of NGC 99 and Lyα clouds in its circumgalactic medium, which suggests a possible pathway for low metallicity gas accretion. We also calculate the resolved Fundamental Metallicity Relation (rFMR) on subkiloparsec scales using localized gas-phase metallicity, stellar mass surface density, and star formation rate surface density. The rFMR shows a similar trend as that found by previous localized and global FMR relations.Item A Photovoltaic Self-Powered Volatile Organic Compounds Sensor Based on Asymmetric Geometry 2D MoS2 Diodes(The Electrochemical Society, 2024-09) Fawzy, Mirette; Reza Mohammadzadeh, Mohammad; Abnavi, Amin; De Silva, Thushani; Ahmadi, Ribwar; Ghanbari, Hamidreza; Kabir, Fahmid; Kavanagh, Karen L.; Hasani, Amirhossein; Adachi, Michael M.Transition metal dichalcogenides have gained considerable interest for vapour sensing applications due to their large surface-to-volume ratio and high sensitivity. Herein, we demonstrate a new self-powered volatile organic compounds (VOC) sensor based on asymmetric geometry multi-layer molybdenum disulfide (MoS2) diode. The asymmetric contact geometry of the MoS2 diode induces an internal built-in electric field resulting in self-powering via a photovoltaic response. While illuminated by UV-light, the sensor exhibited a high responsivity of ∼60% with a relatively fast response time of ∼10 sec to 200 ppm of acetone, without an external bias voltage. The MoS2 VOC diode sensor is a promising candidate for self-powered, fast, portable, and highly sensitive VOC sensor applications.