This open access archive contains publications from University of Arizona faculty, researchers and staff, primarily open-access versions of formally published journal articles. The collection includes published articles and final accepted manuscripts submitted by UA faculty under the UA Open Access Policy. The collection also includes books, book chapters, book reviews, presentations, data, and other scholarly materials submitters have chosen to make available in the repository.


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Recent Submissions

  • Correlation of Electrophysiological and Gene Transcriptional Dysfunctions in Single Cortical Parvalbumin Neurons After Noise Trauma

    Wang, Weihua; Deng, Di; Jenkins, Kyle; Zinsmaier, Alexander K.; Zhou, Qiang; Bao, Shaowen; Department of Physiology, College of Medicine, University of Arizona; Department of Ecology & Evolutionary Biology, University of Arizona (Elsevier BV, 2022-02)
    Parvalbumin-expressing (PV+) interneurons in the sensory cortex form powerful inhibitory synapses on the perisomatic compartments and axon initial segments of excitatory principal neurons (PNs), and perform diverse computational functions. Impaired PV+ interneuron functions have been reported in neural developmental and degenerative disorders. Expression of the unique marker parvalbumin (PV) is often used as a proxy of PV+ interneuron functions. However, it is not entirely clear how PV expression is correlated with PV+ interneuron properties such as spike firing and synaptic transmission. To address this question, we characterized electrophysiological properties of PV+ interneurons in the primary auditory cortex (AI) using whole-cell patch clamp recording, and analyzed the expression of several genes in samples collected from single neurons using the patch pipettes. We found that, after noise induced hearing loss (NIHL), the spike frequency adaptation increased, and the expression of PV, glutamate decarboxylase 67 (GAD67) and Shaw-like potassium channel (KV3.1) decreased in PV+ neurons. In samples prepared from the auditory cortical tissue, the mRNA levels of the target genes were all pairwise correlated. At the single neuron level, however, the expression of PV was significantly correlated with the expression of GAD67, but not KV3.1, maximal spike frequency, or spike frequency adaptation. The expression of KV3.1 was correlated with spike frequency adaptation, but not with the expression of GAD67. These results suggest separate transcriptional regulations of PV/GAD67 vs. KV3.1, both of which are modulated by NIHL.
  • "Did You Leave the Wire in?" A Striking Case of Linear Pulmonary Cement Embolism

    Rao, Shishir; Chopra, Madhav; Puthalapattu, Swathy; Department of Medicine, Critical Care Medicine, University of Arizona; Division of Pulmonary, Critical Care Medicine, University of Arizona (American Thoracic Society, 2021)
  • Transformational ecology and climate change

    Jackson, Stephen T.; Department of Geosciences, University of Arizona (American Association for the Advancement of Science (AAAS), 2021-09-03)
  • Managing for RADical ecosystem change: applying the Resist‐Accept‐Direct (RAD) framework

    Lynch, Abigail J; Thompson, Laura M; Beever, Erik A; Cole, David N; Engman, Augustin C; Hawkins Hoffman, Cat; Jackson, Stephen T; Krabbenhoft, Trevor J; Lawrence, David J; Limpinsel, Douglas; et al. (Wiley, 2021-07-08)
    Ecosystem transformation involves the emergence of persistent ecological or social–ecological systems that diverge, dramatically and irreversibly, from prior ecosystem structure and function. Such transformations are occurring at increasing rates across the planet in response to changes in climate, land use, and other factors. Consequently, a dynamic view of ecosystem processes that accommodates rapid, irreversible change will be critical for effectively conserving fish, wildlife, and other natural resources, and maintaining ecosystem services. However, managing ecosystems toward states with novel structure and function is an inherently unpredictable and difficult task. Managers navigating ecosystem transformation can benefit from considering broader objectives, beyond a traditional focus on resisting ecosystem change, by also considering whether accepting inevitable change or directing it along some desirable pathway is more feasible (that is, practical and appropriate) under some circumstances (the RAD framework). By explicitly acknowledging transformation and implementing an iterative RAD approach, natural resource managers can be deliberate and strategic in addressing profound ecosystem change.
  • More than one way to kill a spruce forest: The role of fire and climate in the late‐glacial termination of spruce woodlands across the southern Great Lakes

    Jensen, Allison M.; Fastovich, David; Watson, Ben I.; Gill, Jacquelyn L.; Jackson, Stephen T.; Russell, James M.; Bevington, Joseph; Hayes, Katherine; Lininger, Katherine B.; Rubbelke, Claire; et al. (Wiley, 2020-11)
    In the southern Great Lakes Region, North America, between 19,000 and 8,000 years ago, temperatures rose by 2.5-6.5 degrees C and spruce Picea forests/woodlands were replaced by mixed-deciduous or pine Pinus forests. The demise of Picea forests/woodlands during the last deglaciation offers a model system for studying how changing climate and disturbance regimes interact to trigger declines of dominant species and vegetation-type conversions. The role of rising temperatures in driving the regional demise of Picea forests/woodlands is widely accepted, but the role of fire is poorly understood. We studied the effect of changing fire activity on Picea declines and rates of vegetation composition change using fossil pollen and macroscopic charcoal from five high-resolution lake sediment records. The decline of Picea forests/woodlands followed two distinct patterns. At two sites (Stotzel-Leis and Silver Lake), fire activity reached maximum levels during the declines and both charcoal accumulation rates and fire frequency were significantly and positively associated with vegetation composition change rates. At these sites, Picea declined to low levels by 14 kyr BP and was largely replaced by deciduous hardwood taxa like ash Fraxinus, hop-hornbeam/hornbeam Ostrya/Carpinus and elm Ulmus. However, this ecosystem transition was reversible, as Picea re-established at lower abundances during the Younger Dryas. At the other three sites, there was no statistical relationship between charcoal accumulation and vegetation composition change rates, though fire frequency was a significant predictor of rates of vegetation change at Appleman Lake and Triangle Lake Bog. At these sites, Picea declined gradually over several thousand years, was replaced by deciduous hardwoods and high levels of Pinus and did not re-establish during the Younger Dryas. Synthesis. Fire does not appear to have been necessary for the climate-driven loss of Picea woodlands during the last deglaciation, but increased fire frequency accelerated the decline of Picea in some areas by clearing the way for thermophilous deciduous hardwood taxa. Hence, warming and intensified fire regimes likely interacted in the past to cause abrupt losses of coniferous forests and could again in the coming decades.
  • Responding to Ecosystem Transformation: Resist, Accept, or Direct?

    Thompson, Laura M.; Lynch, Abigail J.; Beever, Erik A.; Engman, Augustin C.; Falke, Jeffrey A.; Jackson, Stephen T.; Krabbenhoft, Trevor J.; Lawrence, David J.; Limpinsel, Douglas; Magill, Robert T.; et al. (Wiley, 2020-09-15)
    Ecosystem transformation can be defined as the emergence of a self-organizing, self-sustaining, ecological or social-ecological system that deviates from prior ecosystem structure and function. These transformations are occurring across the globe; consequently, a static view of ecosystem processes is likely no longer sufficient for managing fish, wildlife, and other species. We present a framework that encompasses three strategies for fish and wildlife managers dealing with ecosystems vulnerable to transformation. Specifically, managers can resist change and strive to maintain existing ecosystem composition, structure, and function; accept transformation when it is not feasible to resist change or when changes are deemed socially acceptable; or direct change to a future ecosystem configuration that would yield desirable outcomes. Choice of a particular option likely hinges on anticipating future change, while also acknowledging that temporal and spatial scales, recent history and current state of the system, and magnitude of change can factor into the decision. This suite of management strategies can be implemented using a structured approach of learning and adapting as ecosystems change.
  • Investigating Antimicrobial Peptide–Membrane Interactions Using Fast Photochemical Oxidation of Peptides in Nanodiscs

    Reid, Deseree J.; Rohrbough, James G.; Kostelic, Marius M.; Marty, Michael T.; Department of Chemistry and Biochemistry, Bio5 Institute, University of Arizona (American Chemical Society (ACS), 2021-12-06)
    Antimicrobial peptides (AMPs) are an important part of the innate immune system and demonstrate promising applications in the fight against antibiotic-resistant infections due to their unique mechanism of targeting bacterial membranes. However, it is challenging to study the interactions of these peptides within lipid bilayers, making it difficult to understand their mechanisms of toxicity and selectivity. Here, we used fast photochemical oxidation of peptides, an irreversible footprinting technique that labels solvent accessible residues, and native charge detection-mass spectrometry to study AMP-lipid interactions with different lipid bilayer nanodiscs. We observed differences in the oxidation of two peptides, indolicidin and LL-37, in three distinct lipid environments, which reveal their affinity for lipid bilayers. Our findings suggest that indolicidin interacts with lipid head groups via a simple charge-driven mechanism, but LL-37 is more specific for Escherichia coli nanodiscs. These results provide complementary information on the potential modes of action and lipid selectivity of AMPs.
  • Kinetic Alfvénic cnoidal waves in Saturnian magnetospheric plasmas

    Singh, Manpreet; Singh, Kuldeep; Saini, N. S.; Department of Planetary Sciences-Lunar and Planetary Laboratory, University of Arizona (Informa UK, 2021-12-28)
    The characteristics of kinetic Alfvénic cnoidal waves (KACWs) in Saturn's magnetosphere plasma composed of two temperature superthermal electrons and inertial ions are presented. The Korteweg–de Vries (KdV) equation and its cnoidal wave solution are derived by adopting reductive perturbation technique. Only positive potential kinetic Alfvénic cnoidal and solitary waves are evolved in Saturnian magnetospheric plasma. The influence of superthermality of cold electrons, concentration of hot electrons, plasma beta and angle of propagation of the wave with respect to the magnetic field has been analyzed on the characteristics of KACWs. The findings of this investigation may shed the light on the possible existence of KACWs and acceleration as well as energy transportation in space plasmas especially in Saturn's magnetosphere.
  • A New Approach to Evaluate and Reduce Uncertainty of Model-Based Biodiversity Projections for Conservation Policy Formulation

    Myers, Bonnie J E; Weiskopf, Sarah R; Shiklomanov, Alexey N; Ferrier, Simon; Weng, Ensheng; Casey, Kimberly A; Harfoot, Mike; Jackson, Stephen T; Leidner, Allison K; Lenton, Timothy M; et al. (Oxford University Press (OUP), 2021-10-13)
    Biodiversity projections with uncertainty estimates under different climate, land-use, and policy scenarios are essential to setting and achieving international targets to mitigate biodiversity loss. Evaluating and improving biodiversity predictions to better inform policy decisions remains a central conservation goal and challenge. A comprehensive strategy to evaluate and reduce uncertainty of model outputs against observed measurements and multiple models would help to produce more robust biodiversity predictions. We propose an approach that integrates biodiversity models and emerging remote sensing and in-situ data streams to evaluate and reduce uncertainty with the goal of improving policy-relevant biodiversity predictions. In this article, we describe a multivariate approach to directly and indirectly evaluate and constrain model uncertainty, demonstrate a proof of concept of this approach, embed the concept within the broader context of model evaluation and scenario analysis for conservation policy, and highlight lessons from other modeling communities.
  • In-situ testing of organic photovoltaic (OPV) modules to examine modes of degradation in an arid-hot climate

    Chief, Manuelito; Boyer, Kyle; Simmons-Potter, Kelly; University of Arizona, Department of Electrical and Computer Engineering (SPIE, 2020-09-14)
    The AzRISE-TEP Solar Test Yard is a 600-module capacity test bed that provides the environment for in-situ testing of PV module performance, with real-time data collection of module power production and local weather conditions. This work involves the examination of flexible, semi-transparent, organic photovoltaic (OPV) modules in an outdoor testing environment to study degradation in the hot, arid, Tucson, AZ climate. The work reports on changes in the I-V performance and efficiency of a string of two OPV modules in order to estimate degradation experienced by the OPV modules. The study finds that the module string under test dropped to below 80% of its initial power conversion efficiency (PCE) after 54.58 days, and predicts that the PCE will drop below 50% of its initial state after 114.53 days from deployment.
  • Electroluminescence image analysis of a photovoltaic module under accelerated lifecycle testing

    Lai, Teh; Potter, B G; Simmons-Potter, Kelly; Univ Arizona, Dept Elect & Comp Engn; Univ Arizona, Dept Opt Sci; Univ Arizona, Dept Mat Sci & Engn (OPTICAL SOC AMER, 2020)
    Electroluminescence (EL) imaging of Si-based photovoltaic (PV) modules is used widely to spatially detect and characterize electrical defects, including handling and degradation-induced cracking of the component Si cells that are associated with reductions in module performance. In the present study, a commercial polycrystalline silicon PV module was subjected to accelerated lifecycle test environmental conditions and examined as a function of environmental exposure time using EL imaging. The approach followed pixel intensity distributions over each individual PV cell and confirmed a positive correlation between module conversion efficiency and results of the image analysis. Overall, an average of a 2.5% reduction in normalized EL intensity was correlated to a 0.35% reduction in actual power conversion efficiency (or a 2.3% decrease in relative efficiency). The imaging analysis technique offers a rapid, unsupervised means to assess EL data in lieu of conventional visual interpretation.
  • Barriers and facilitators for adopting a healthy lifestyle among Latina cancer survivors: A qualitative descriptive study

    Dolan, Hanne R.; Alvarez, Alexis A.; Freylersythe, Sarah J.; Penaloza, Irlena; Grijalva, Sofia; Taylor-Piliae, Ruth; Crane, Tracy E.; University of Arizona Cancer Center; College of Nursing, University of Arizona (Springer Science and Business Media LLC, 2021-11-24)
    Purpose: Cancer is the leading cause of death among Hispanics/Latinos in the USA. Latina cancer survivors experience higher symptom burden than other cancer survivors. A healthy lifestyle can decrease recurrent cancer risk, increase well-being, and may decrease symptom burden in cancer survivors. The purpose of this study was to explore the barriers and facilitators for adopting healthy lifestyle behaviors among Latina cancer survivors. Methods: Using the Health Belief Model as the theoretical framework, qualitative descriptive methodology was used for secondary analysis of data from a previously conducted randomized clinical trial. Transcripts from the telephone health coaching calls, analyzed in the original language (English or Spanish), were used for this qualitative analysis. Results: Intervention telephone call transcript data from Latina cancer survivors (n = 14) were analyzed. Major themes were as follows: Perceived susceptibility to other chronic illnesses, perceived benefits of a healthy lifestyle, and perceived barriers and facilitators of adopting a healthy lifestyle. Lack of knowledge about healthy lifestyle behaviors could prevent participants from adopting a healthy lifestyle; gaining new knowledge about healthy lifestyle behaviors was a facilitator for changing lifestyle. Family responsibility and wearable technology could both prevent and motivate the participants to adopt a healthy lifestyle. Conclusion: Developing culturally appropriate interventions for Latina cancer survivors is vital to decrease symptom burden and health risks, as well as improve health outcomes in this population.
  • Socially distributed leadership in elementary schools: teacher and staff leadership practice in Denmark and the USA

    Modeste, Marsha E.; Nguyen, Chi; Nafziger, Rhoda Nanre; Hermansen, Jonathan; University of Arizona (Emerald, 2021-12-24)
    Purpose: The purpose of this study is to examine the nature of socially distributed leadership in Denmark and the USA, specifically teacher and staff leadership practices distributed in schools. Design/methodology/approach: This study used a confirmatory factor analysis and a second-order factor analysis to examine elementary USA and 0–9 Danish school educators’ responses to the Comprehensive Assessment of Leadership for Learning. Findings: Findings from this analysis of leadership practice demonstrate (1) different approaches to teacher and staff leadership in Denmark and the USA; (2) the importance of a collaborative approach to developing and maintaining professional learning communities in schools in both contexts; and (3) different patterns of leadership practice that broadly reflect the local structure and approach to school leadership while responding to external policy demands. Originality/value: Drawing on the globalization scholarship, which acknowledges the connection between global policy development and local spaces of implementation, this comparative international study allowed us to examine how policy ideas are parlayed into practice through the use of a shared assessment of leadership practice. The results of this study suggest that while the work of teacher and staff leadership is important and something that educators in Denmark and the USA are engaging in to advance the overall instructional mission of their schools, the approaches taken in each context are different and reflect a local-level negotiation between contextual cultural norms and policy expectations.
  • Ecological generalism drives hyperdiversity of secondary metabolite gene clusters in xylarialean endophytes

    Franco, Mario E E; Wisecaver, Jennifer H; Arnold, A Elizabeth; Ju, Yu-Ming; Slot, Jason C; Ahrendt, Steven; Moore, Lillian P; Eastman, Katharine E; Scott, Kelsey; Konkel, Zachary; et al. (John Wiley and Sons Inc, 2021-12-07)
    - Although secondary metabolites are typically associated with competitive or pathogenic interactions, the high bioactivity of endophytic fungi in the Xylariales, coupled with their abundance and broad host ranges spanning all lineages of land plants and lichens, suggests that enhanced secondary metabolism might facilitate symbioses with phylogenetically diverse hosts. - Here, we examined secondary metabolite gene clusters (SMGCs) across 96 Xylariales genomes in two clades (Xylariaceae s.l. and Hypoxylaceae), including 88 newly sequenced genomes of endophytes and closely related saprotrophs and pathogens. We paired genomic data with extensive metadata on endophyte hosts and substrates, enabling us to examine genomic factors related to the breadth of symbiotic interactions and ecological roles. - All genomes contain hyperabundant SMGCs; however, Xylariaceae have increased num- bers of gene duplications, horizontal gene transfers (HGTs) and SMGCs. Enhanced metabolic diversity of endophytes is associated with a greater diversity of hosts and increased capacity for lignocellulose decomposition. - Our results suggest that, as host and substrate generalists, Xylariaceae endophytes experi- ence greater selection to diversify SMGCs compared with more ecologically specialised Hypoxylaceae species. Overall, our results provide new evidence that SMGCs may facilitate symbiosis with phylogenetically diverse hosts, highlighting the importance of microbial sym- bioses to drive fungal metabolic diversity.
  • How to decode interstellar messages

    Matessa, Michael; Vakoch, Douglas A.; Lower, Timothy A.; Barkow, Jerome H.; DeVito, Carl L.; Department of Mathematics, University of Arizona (Elsevier BV, 2022-03)
    How can we determine the meaning of a message from a distant civilization if we do not have a common language? This paper presents a general technique and principles for decoding interstellar messages: First, find the dimension of the message. Prime numbers may be useful in determining the proportions of messages. Next, find the symbols. This can be done considering symbol types: delimiters, values, relationships, and functions. Then, find the symbol meanings. Features that can help in determining meaning include sub-symbolic type, redundant symbols, expression consistency, physics ratios, and physics expression patterns. Concepts in this paper can be used when a message from another civilization is received, or they can be used to create messages, which can teach communication theory concepts.
  • The Scope of Rape Victimization and Perpetration Among National Samples of College Students Across 30 years

    Koss, Mary P.; Swartout, Kevin M.; Lopez, Elise C.; Lamade, Raina V.; Anderson, Elizabeth J.; Brennan, Carolyn L.; Prentky, Robert A.; Department of Health Promotion Sciences, Mel and Enid Zuckerman College of Public Health, University of Arizona (SAGE Publications, 2021-12-15)
    Research Questions: Rape prevention practice and policy have roots in data from 1985. This study uses 2015 national data to project recent prevalence, assesses whether rates now differ from those of 30 years ago, and disaggregates 2015 prevalence into rape of alcohol incapacitated victims, rapes combining both alcohol and physical tactics, and violent rape. Methods: Cross-sectional analyses were conducted comparing two national samples. The first was collected in 1984-85 (Koss, Gidycz, & Wisniewski, 1987); the second was collected 30 years later in 2014-2015. Both surveys used in-person administration and measurement by the most current version at the time of the Sexual Experiences Survey (SES). Prevalence rates were compared using Bayesian binomial tests. Results: In 2015, 33.4% (1 in 3) of women reported experiencing rape or attempted rape and 12.7% of men reported perpetration (1 in 8). Using Jeffreys' label for effect size of the Bayes binomial (1961), both results are “decisively” greater than expected given the 1985 benchmarks of 27.9% for victimization and 7.7% for perpetration. Victimization when incapacitated characterized approximately 75% of incidents in 2015 up from 50% in 1985. Cautions apply as cross-sectional data does not establish causality and the recent data set involved the revised SES. Conclusions: Across 30 years, neither containment nor reduction of rape was demonstrated and the increasingly prominent association with alcohol was apparent. Among the men who disclosed raping, 9 of 10 incidents were alcohol-involved. Prevention focus might profitably be directed to constraining alcohol environments and policies that facilitate rape of incapacitated persons and on misconduct responses that are proportional to the harm caused to rape victims, thereby raising the perceived risks of perpetration.
  • Holistic insights from pollen omics: co-opting stress-responsive genes and ER-mediated proteostasis for male fertility

    Sze, Heven; Palanivelu, Ravishankar; Harper, Jeffrey F; Johnson, Mark A; School of Plant Sciences, University of Arizona (Oxford University Press (OUP), 2021-10-02)
    Sexual reproduction in flowering plants takes place without an aqueous environment. Sperm are carried by pollen through air to reach the female gametophyte, though the molecular basis underlying the protective strategy of the male gametophyte is poorly understood. Here we compared the published transcriptomes of Arabidopsis thaliana pollen, and of heat-responsive genes, and uncovered insights into how mature pollen (MP) tolerates desiccation, while developing and germinating pollen are vulnerable to heat stress. Germinating pollen expresses molecular chaperones or “heat shock proteins” in the absence of heat stress. Furthermore, pollen tubes that grew through pistils at basal temperature showed induction of the endoplasmic reticulum (ER) stress response, which is a characteristic of stressed vegetative tissues. Recent studies show MP contains mRNA-protein (mRNP) aggregates that resemble “stress” granules triggered by heat or other stresses to protect cells. Based on these observations, we postulate that mRNP particles are formed in maturing pollen in response to developmentally programmed dehydration. Dry pollen can withstand harsh conditions as it is dispersed in air. We propose that, when pollen lands on a compatible pistil and hydrates, mRNAs stored in particles are released, aided by molecular chaperones, to become translationally active. Pollen responds to osmotic, mechanical, oxidative, and peptide cues that promote ER-mediated proteostasis and membrane trafficking for tube growth and sperm discharge. Unlike vegetative tissues, pollen depends on stress-protection strategies for its normal development and function. Thus, heat stress during reproduction likely triggers changes that interfere with the normal pollen responses, thereby compromising male fertility. This holistic perspective provides a framework to understand the basis of heat-tolerant strains in the reproduction of crops.
  • A Theory of the Merging Noospheres: Teilhard and Big History

    Campa, Riccardo; Corbally, Christopher; Rappaport, Margaret Boone; Department of Astronomy, University of Arizona (Informa UK Limited, 2021-12-12)
    As the number of detected Earth-like exoplanets keeps increasing, the prospect of contact with extraterrestrial civilizations becomes day after day more plausible. It has been noticed that the encounter between space civilizations implies a fusion of Big Histories. By following Teilhard, the authors argue that the hypothetical contact with alien intelligent life would also result in a merging of the noospheres. The long-term perspective of this process is the awakening of the entire universe. This article provides a history of the idea of noosphere, a reconstruction of Teilhard’s “sociological theory,” and an exploration of the theological consequences of his theory.
  • Sinuous channels east of Olympus Mons, Mars: Implications for volcanic, hydrological, and tectonic processes

    Sutton, Sarah S.; Hamilton, Christopher W.; Cataldo, Vincenzo; Williams, David A.; Bleacher, Jacob E.; Lunar and Planetary Laboratory, University of Arizona (Elsevier BV, 2022-03)
    The Late Amazonian volcanic plains east of Olympus Mons contain numerous channels and fossae. Channel formation hypotheses have included volcanic processes, flowing water, or a combination of both. To evaluate these hypotheses, we conducted detailed geomorphological and facies mapping at two sites containing channels and fossae representative of features in the region. Based on our mapping and morphological analyses using high resolution topography and images from HiRISE and CTX data, we classified channels into three types, and fossae into two types. Channel Type 1 and Type 2 are consistent with the morphology of lava channels, however, we found no evidence of channel formation due to thermo-mechanical erosion. Additionally, we calculated the potential for lava to achieve turbulent flow within our two study sites and found it unlikely. Channel Type 3 is consistent with fluvial bedrock erosion, likely sourced from erupted groundwater that entrained regolith into lahar-like flows. Fossae are classified as linear (Type L) or arcuate and branched (Type A). Type L fossae are interpreted to be surface fractures associated with dike emplacement, whereas Type A fossae are interpreted to be surface fractures due to sill emplacement, which may have melted buried ice deposits and generated meltwater floods. Type 1 and Type 2 channels are associated with Type L fossae and fissure-fed effusive eruptions of lava. In contrast, Type 3 channels are co-located with Type A fossae, and are likely due to outbursts of groundwater possibly related to sill emplacement. We attribute the formation and distribution of channels and fossae throughout the plains east of Olympus Mons to be a consequence of the region's evolving states of stress, which are predominantly influenced by the loading of Olympus Mons. © 2021 Elsevier Inc.
  • Pattern-based downscaling of snowpack variability in the western United States

    Gauthier, Nicolas; Anchukaitis, Kevin J.; Coulthard, Bethany; School of Geography, Development and Environment, University of Arizona; Laboratory of Tree-Ring Research, University of Arizona (Springer Science and Business Media LLC, 2021-12-27)
    The decline in snowpack across the western United States is one of the most pressing threats posed by climate change to regional economies and livelihoods. Earth system models are important tools for exploring past and future snowpack variability, yet their coarse spatial resolutions distort local topography and bias spatial patterns of accumulation and ablation. Here, we explore pattern-based statistical downscaling for spatially-continuous interannual snowpack estimates. We find that a few leading patterns capture the majority of snowpack variability across the western US in observations, reanalyses, and free-running simulations. Pattern-based downscaling methods yield accurate, high resolution maps that correct mean and variance biases in domain-wide simulated snowpack. Methods that use large-scale patterns as both predictors and predictands perform better than those that do not and all are superior to an interpolation-based “delta change” approach. These findings suggest that pattern-based methods are appropriate for downscaling interannual snowpack variability and that using physically meaningful large-scale patterns is more important than the details of any particular downscaling method.

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