• Restoring Palmer's agave in a Lehmann lovegrass dominated grassland in southeastern Arizona

  Gill, Amy S.; Oliver, Jeffrey C.; Fitting, Helen; Kubby, Brooke K.; Gornish, Elise S.; School of Natural Resources and the Environment, University of Arizona; Research Engagement, University Libraries, University of Arizona (Wiley, 2022-04-19)

  Dryland restoration is becoming increasingly challenging in arid and semiarid regions, such as in the southwestern United States, due to rapid land degradation, the spread of non-native species, and climate change. The development of strategies to enhance restoration of native species, particularly culturally and ecologically important native plants like Palmer's agave (Agave palmeri), is particularly critical in southeastern arid lands where scarce rainfall, herbivory, and invasive species dominance pose unique challenges to land management. In a large field experiment in southeastern Arizona, U.S.A., we assessed the utility of several management techniques to promote restoration and revegetation outcomes for Palmer's agave survival and growth, including protection from solar insolation and herbivory, and reduction in the competitiveness of Lehmann lovegrass (Eragrostis lehmanniana). We found that the combination of herbivory protection and shade resulted in the highest survival of planted agaves, while the shade treatment alone resulted in the largest agaves. In fact, our results suggest that dense Lehmann lovegrass cover protects agaves from direct sunlight and predation. If land managers are challenged by widespread Lehmann lovegrass, they can opt to mechanically reduce it. However, if population recovery of Palmer's agave is a priority and fire hazard is minimal, our work suggests that stakeholders concerned with population recovery of Palmer's agave can forgo removing existing vegetation and plant agaves in a matrix of (and/or under the canopy of) existing vegetation.
• Early age-related atrophy of cutaneous lymph nodes precipitates an early functional decline in skin immunity in mice with aging

  Sonar, Sandip Ashok; Uhrlaub, Jennifer L; Coplen, Christopher P; Sempowski, Gregory D; Dudakov, Jarrod A; van den Brink, Marcel R M; LaFleur, Bonnie J; Jergović, Mladen; Nikolich-Žugich, Janko; Department of Immunobiology, University of Arizona College of Medicine-Tucson; et al. (PNAS, 2022-04-19)

  Significance: Older adults are more vulnerable to infection and less capable of vigorously responding to vaccination. The contribution of peripheral T cell maintenance defects to these processes is incompletely understood. Here, we provide evidence that lymph nodes (LNs), which are critical for naive T (TN) cell maintenance and initiation of new immune responses, age asynchronously. Skin-draining LNs undergo early (6 to 9 mo) and deeper LN and spleen late-life (18 mo) atrophy, characterized by reduced ability to maintain TN cells, structural and numerical loss of LN stromal cell microenvironments, and reduced immunity to cutaneous vaccination. These results highlight the critical role of age-related LN atrophy in functional immunity and immune homeostasis.
• Assessing the Sampleability of Bennu’s Surface for the OSIRIS-REx Asteroid Sample Return Mission

  Walsh, Kevin J.; Bierhaus, Edward B.; Lauretta, Dante S.; Nolan, Michael C.; Ballouz, Ronald-Louis; Bennett, Carina A.; Jawin, Erica R.; Barnouin, Olivier S.; Berry, Kevin; Burke, Keara N.; et al. (Springer Science and Business Media LLC, 2022-04-19)

  NASA’s first asteroid sample return mission, OSIRIS-REx, collected a sample from the surface of near-Earth asteroid Bennu in October 2020 and will deliver it to Earth in September 2023. Selecting a sample collection site on Bennu’s surface was challenging due to the surprising lack of large ponded deposits of regolith particles exclusively fine enough (≤2cm diameter) to be ingested by the spacecraft’s Touch-and-Go Sample Acquisition Mechanism (TAGSAM). Here we describe the Sampleability Map of Bennu, which was constructed to aid in the selection of candidate sampling sites and to estimate the probability of collecting sufficient sample. “Sampleability” is a numeric score that expresses the compatibility of a given area’s surface properties with the sampling mechanism. The algorithm that determines sampleability is a best fit functional form to an extensive suite of laboratory testing outcomes tracking the TAGSAM performance as a function of four observable properties of the target asteroid. The algorithm and testing were designed to measure and subsequently predict TAGSAM collection amounts as a function of the minimum particle size, maximum particle size, particle size frequency distribution, and the tilt of the TAGSAM head off the surface. The sampleability algorithm operated at two general scales, consistent with the resolution and coverage of data collected during the mission. The first scale was global and evaluated nearly the full surface. Due to Bennu’s unexpected boulder coverage and lack of ponded regolith deposits, the global sampleability efforts relied heavily on additional strategies to find and characterize regions of interest based on quantifying and avoiding areas heavily covered by material too large to be collected. The second scale was site-specific and used higher-resolution data to predict collected mass at a given contact location. The rigorous sampleability assessments gave the mission confidence to select the best possible sample collection site and directly enabled successful collection of hundreds of grams of material.
• Faculty Senate Minutes April 4, 2022

  University of Arizona Faculty Senate (University of Arizona Faculty Senate (Tucson, AZ), 2022-04-04)
• Evaluating socially engaged climate research: Scientists’ visions of a climate resilient US Southwest

  Owen, Gigi; Climate Assessment for the Southwest, University of Arizona; Arizona Institutes for Resilient Environments and Societies, University of Arizona (Oxford University Press, 2021-01)

  Socially engaged science and collaborative research practices offer promising ways to address complex environmental and societal problems like climate variability and climate change. However, it is unclear if and how these types of collaborative knowledge production result in tangible impacts. Drawing from a 6-year evaluation, this article investigates the outcomes and contributions of ten collaborative research projects supported by a federally funded climate research program in the US Southwest. Based on a series of narratives that outline researchers’ objectives, anticipated outcomes are compared to those that emerged over a 6-year period. Results indicate several contributions that the program has made toward raising awareness about climate issues in the US Southwest, increasing capacity to adapt to climate change and climate variability, and building lasting individual and institutional collaborative relationships. However, researchers sometimes envision direct applications of their work, such as informing policy, planning, and decision-making, to be different than what occurred within the 6-year timeframe. Further exploration of these results reveals implicit assumptions in understanding how scientific information translates into use. This article offers insight into how researchers envision their impact, the management and development of a mission-oriented research program, and the use of evaluation to understand how collaborative research contributes to societal and environmental change.

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