• Square-shaped sensor clusters for acoustic source localization in anisotropic plates by wave front shape-based approach

      Sen, Novonil; Gawroński, Mateusz; Packo, Pawel; Uhl, Tadeusz; Kundu, Tribikram; Department of Aerospace and Mechanical Engineering, University of Arizona; Department of Civil and Architectural Engineering and Mechanics, University of Arizona (Elsevier BV, 2021-05)
      Various techniques have emerged in the past few years for localizing the acoustic source in an anisotropic plate. The wave front shape-based approach, one of the recent additions to this field of research, has the advantage of circumventing the unrealistic assumption of a straight line wave propagation path through an anisotropic medium. In their most recent versions, the two major wave front shape-based techniques (i.e., the ellipse- and the parametric curve-based techniques) are applicable to the situations with an unknown orientation of the axes of symmetry of an anisotropic plate. However, this approach still relies on estimating the angle of wave-incidence at a given location of the plate via a single L-shaped sensor cluster. The incidence angle so obtained may deviate significantly from the true angle of wave arrival. To improve the estimation accuracy of the incidence angle, in the present study a square-shaped cluster composed of four densely-spaced sensors forming the four vertices of a square is proposed to be installed at the location of interest. Essentially, a square-shaped sensor cluster contains four L-shaped clusters oriented in different directions. A formulation to estimate the angle of incidence from the signal data acquired by a squared-shaped cluster is presented. The wave front shape-based approach can then be applied to estimate the acoustic source location. A numerical study is conducted to illustrate the proposed methodology. Performance comparisons between square- and L-shaped clusters reveal that in general the square-shaped clusters lead to more accurate source location estimates than the L-shaped clusters. © 2020 Elsevier Ltd
    • Deuterium as a quantitative tracer of enhanced microbial methane production

      Ashley, Kilian; Davis, Katherine J.; Martini, Anna; Vinson, David S.; Gerlach, Robin; Fields, Matthew W.; McIntosh, Jennifer; Department of Hydrology and Atmospheric Sciences, University of Arizona (Elsevier BV, 2021-04)
      Microbial production of natural gas in subsurface organic-rich reservoirs (e.g., coal, shale, oil) can be enhanced by the introduction of amendments (e.g., algal extracts from biofuel production) to stimulate microbial communities to generate “new” methane resources on human timescales, potentially providing a lower carbon energy source. This study tests deuterated water as a tracer to quantify the amount of “new” methane generated and the effectiveness of Microbial Enhancement of Coalbed Methane (MECoM) approaches, as methanogens incorporate hydrogen from formation waters into methane during methanogenesis. Microorganisms (including methanogens), formation water, and coal obtained from the Powder River Basin were used to establish batch reactor stimulation experiments, using algal extracts, in which incremental amounts of deuterated water were added. The greatest amount of methane was produced in the amended coal-associated experiments and there was a consistent uptake of D into microbial methane. The shorter duration (36 days) coal amended experiment had a lower slope (m = 0.31) of δD-CH4 vs. δD-H2O and a similar offset between δD-H2O and δD-CH4 (371.2‰) compared to the longer duration (m = 0.44; 114 days; 358.8‰ offset) experiment, both consistent with the stimulation of primarily acetoclastic methanogenesis. The success of our proof-of-concept laboratory experiments confirms that deuterated water can be used as a quantitative tracer of stimulated coal-associated methanogenic activity. We also provide an example of how it can be applied in field-scale MECoM projects. In addition, deuterated water may serve as a useful tracer for other natural or enhanced subsurface microbial activities, such as microbial enhanced oil recovery or bioremediation of organic contaminants. © 2020 Elsevier Ltd
    • Trisomy 21 impairs PGE2 production in dermal fibroblasts

      Marentette, John O.; Anderson, Colin C.; Prutton, Kendra M.; Jennings, Erin Q.; Rauniyar, Abhishek K.; Galligan, James J.; Roede, James R.; Skaggs School of Pharmacy, University of Arizona (Elsevier BV, 2021-04)
      The triplication of human chromosome 21 results in Down syndrome (DS), the most common genetic form of intellectual disability. This aneuploid condition also results in an enhanced risk of a spectrum of comorbid conditions, such as leukemia, early onset Alzheimer's disease, and diabetes. Individuals with DS also display an increased incidence of wound healing complications and resistance to solid tumor development. Due to this unique phenotype and the involvement of eicosanoids in key comorbidities like poor healing and tumor development, we hypothesized that cells from DS individuals would display altered eicosanoid production. Using age- and sex-matched dermal fibroblasts we interrogated this hypothesis. Briefly, assessment of over 90 metabolites derived from cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome p450 systems revealed a possible deficiency in the COX system. Basal gene expression and Western blotting experiments showed significantly decreased gene expression of COX1 and 2, and COX2 protein abundance in DS fibroblasts compared to euploid controls. Further, using two different stressors, scratch wound or LPS, we found that DS fibroblasts could not upregulate COX2 abundance and prostaglandin E2 production. Together, these findings show that dermal fibroblasts from DS individuals have a deficient COX2 response, which may contribute to wound healing complications and tumor resistance in DS. © 2020 Elsevier Inc.
    • Association of Visual Acuity with Eye-Related Quality of Life and Functional Vision Across Childhood Eye Conditions

      Leske, David A.; Hatt, Sarah R.; Wernimont, Suzanne M.; Castañeda, Yolanda S.; Cheng-Patel, Christina S.; Liebermann, Laura; Birch, Eileen E.; Holmes, Jonathan M.; Department of Ophthalmology and Vision Science, University of Arizona (Elsevier BV, 2021-03)
      Purpose: We evaluated relationships between visual acuity (VA) and eye-related quality of life and functional vision in children, across a spectrum of pediatric eye conditions, using the Pediatric Eye Questionnaire (PedEyeQ). Design: Cross-sectional study. Methods: Three hundred ninety-seven children (5-11 years of age) with an eye condition and 104 visually normal control subjects completed the Child PedEyeQ (functional vision, bothered by eyes/vision, social, and frustration/worry domains). One parent for each child completed the Proxy PedEyeQ (same domains as child plus eye care) and parent PedEyeQ (impact on parent and family, worry about child's eye condition, worry about child's self-perception and interactions, and worry about functional vision domains). Each domain was Rasch-scored and Spearman rank correlations were calculated to evaluate relationships between better-seeing-eye and worse-seeing-eye VA and PedEyeQ domain score. Results: There was a significant relationship between poorer better-seeing-eye VA and lower (worse) PedEyeQ score on 2 of 4 child domains (e.g., functional vision, r = −0.1474; P = .005), on 2 of 5 proxy PedEyeQ domains (e.g., functional vision, r = −0.2183; P < .001), and on 2 of 4 parent PedEyeQ domains (e.g., impact on parent and family, r = −0.1607; P = .001). Worse-seeing-eye VA was associated with lower PedEyeQ scores across all child, proxy and parent domains (P < .01 for each) with the exception of the child social domain (P = .15). Conclusions: Both better-seeing-eye and worse-seeing-eye VA were associated with functional vision and eye-related quality of life in children, assessed using the PedEyeQ, although other factors may also influence relationships. These data further validate using the PedEyeQ across pediatric eye conditions. © 2020 Elsevier Inc.
    • Viscoelasticity of children and adolescent brains through MR elastography

      Ozkaya, Efe; Fabris, Gloria; Macruz, Fabiola; Suar, Zeynep M.; Abderezaei, Javid; Su, Bochao; Laksari, Kaveh; Wu, Lyndia; Camarillo, David B.; Pauly, Kim B.; et al. (Elsevier BV, 2021-03)
      Magnetic Resonance Elastography (MRE) is an elasticity imaging technique that allows a safe, fast, and non-invasive evaluation of the mechanical properties of biological tissues in vivo. Since mechanical properties reflect a tissue's composition and arrangement, MRE is a powerful tool for the investigation of the microstructural changes that take place in the brain during childhood and adolescence. The goal of this study was to evaluate the viscoelastic properties of the brain in a population of healthy children and adolescents in order to identify potential age and sex dependencies. We hypothesize that because of myelination, age dependent changes in the mechanical properties of the brain will occur during childhood and adolescence. Our sample consisted of 26 healthy individuals (13 M, 13 F) with age that ranged from 7-17 years (mean: 11.9 years). We performed multifrequency MRE at 40, 60, and 80 Hz actuation frequencies to acquire the complex-valued shear modulus G = G′ + iG″ with the fundamental MRE parameters being the storage modulus (G′), the loss modulus (G″), and the magnitude of complex-valued shear modulus (|G|). We fitted a springpot model to these frequency-dependent MRE parameters in order to obtain the parameter α, which is related to tissue's microstructure, and the elasticity parameter k, which was converted to a shear modulus parameter (μ) through viscosity (η). We observed no statistically significant variation in the parameter μ, but a significant increase of the microstructural parameter α of the white matter with increasing age (p < 0.05). Therefore, our MRE results suggest that subtle microstructural changes such as neural tissue's enhanced alignment and geometrical reorganization during childhood and adolescence could result in significant biomechanical changes. In line with previously reported MRE data for adults, we also report significantly higher shear modulus (μ) for female brains when compared to males (p < 0.05). The data presented here can serve as a clinical baseline in the analysis of the pediatric and adolescent brain's viscoelasticity over this age span, as well as extending our understanding of the biomechanics of brain development.
    • Pathways to better nutrition in South Asia: Evidence on the effects of food and agricultural interventions

      Dizon, Felipe; Josephson, Anna; Raju, Dhushyanth; University of Arizona (Elsevier BV, 2021-03)
      In South Asia, nearly half a billion people are malnourished. This paper examines the links of food and agriculture with nutrition in South Asia, with the goal of informing policy to reduce hunger and malnutrition in the region. We investigate pathways including public food transfer programs, agricultural diversification, and different methods of food fortification. We find that public food transfer programs, used to make food available and affordable to poor households, are often unable to significantly protect or promote nutrition. But several supply-side food and agricultural interventions show promise in improving nutrition, although their effects have yet to be well identified. These include the cultivation of home gardens, animal agriculture, and use of biofortification and post-harvest fortification. All these efforts to reduce hunger and malnutrition will be futile, however, without parallel efforts to mitigate rising challenges in the region, including those posed by climate change, urbanization, food loss and food waste, and food safety hazards. © 2020 Elsevier B.V.
    • Novel insecticides and generalist predators support conservation biological control in cotton

      Bordini, Isadora; Ellsworth, Peter C.; Naranjo, Steven E.; Fournier, Alfred; University of Arizona, Department of Entomology (Elsevier BV, 2021-03)
      Arizona has a successful integrated pest management plan for arthropod pests of cotton including two key pests, Bemisia argentifolii (=B. tabaci MEAM1) and Lygus hesperus. Central to this plan is conservation of natural enemies through threshold-based use of effective and selective insecticides. Field studies were designed to test the selectivity of the insecticides cyantraniliprole, flupyradifurone, pyrifluquinazon and sulfoxaflor on the cotton arthropod community (27 taxa measured), which includes the key generalist predator taxa: Collops spp., Orius tristicolor, Geocoris spp., Misumenops celer, Drapetis nr. divergens and Chrysoperla carnea s.l. Compared with an untreated check and in contrast to acephate-treated positive controls, predator densities were rarely affected, and the overall arthropod predator community was conserved by all insecticides. Occasional significant reductions in predator abundances were likely associated with lower prey availability after insecticide sprays rather than direct toxic effects. The proportions of time that predator to prey ratios were at or above levels indicative of functioning biological control were either significantly higher or not significantly different from the untreated check for these insecticides. The cotton food web populated by generalist predators is resilient and flexible enough to accommodate temporary reductions in abundance of some species, periods of low prey densities, or other constraints on individual predator species function. Our study demonstrates that the insecticides tested are selective and compatible with sustainable pest management in the Arizona cotton system, representing new options for insect pest control that conserve natural enemies and support biological control through generally favorable changes to predator to prey ratios. © 2020 The Authors
    • Social context-dependent singing alters molecular markers of synaptic plasticity signaling in finch basal ganglia Area X

      So, Lisa Y.; Miller, Julie E.; Univ Arizona, Dept Neurosci; Univ Arizona, Dept Speech Language & Hearing Sci (Elsevier BV, 2021-02)
      Vocal communication is a crucial skill required throughout life. However, there is a critical gap in our understanding of the underlying molecular brain mechanisms, thereby motivating our use of the zebra finch songbird model. Adult male zebra finches show differences in neural activity patterns in song-dedicated brain nuclei when they sing in two distinct social contexts: a male singing by himself (undirected, UD) and a male singing to a female (female-directed, FD). In our prior work, we showed that in song-dedicated basal ganglia Area X, protein levels of a N-methyl-D-aspartate receptor subtype 2B (NMDAR2B) increased with more UD song and decreased with more FD song. We hypothesized that molecules downstream of this receptor would show differential protein expression levels in Area X between UD and FD song. Specifically, we investigated calcium/calmodulin dependent protein kinase II beta (CaMKIIB), homer scaffold protein 1 (HOMER1), serine/threonine protein kinase (Akt), and mechanistic target of rapamycin kinase (mTOR) following singing and non-singing states in Area X. We show relationships between social context and protein levels. HOMER1 protein levels decreased with time spent singing FD song, and mTOR protein levels decreased with the amount of and time spent singing FD song. For both HOMER1 and mTOR, there were no differences with the amount of UD song. With time spent singing UD, CaMKIIB protein levels trended in a U-shaped curve whereas Akt protein levels trended down. Both molecules showed no change with FD song. Our results support differential involvement of molecules in synaptic plasticity pathways between UD and FD song behaviors.
    • Forward kinematic modeling of fault-bend folding

      Connors, Christopher D.; Hughes, Amanda N.; Ball, Stephen M.; Department of Geosciences, University of Arizona (Elsevier BV, 2021-02)
      We present a forward numerical modeling approach for fault-bend folding based on a velocity description of deformation. The approach incorporates algorithms capable of modeling multiple fault bends of different geometries (e. g. fault bends not stepping up from a detachment), imbricates, and variable velocity-boundary orientations, with corresponding varying slip ratios. When modeling contraction, the approach is capable of reproducing rounded-hinges and parallel folds with localized bed thinning or thickening commonly observed in natural structures. Extensional fault-bend folds can be modeled using the same set of equations, with the minor modification that velocity boundary orientations are defined independently of the fault shape. The modeled structures conserve area, and commonly observed features of extensional fault-bend folds, such as rollover structures with growth, are produced. Thus, we present a unified inclined-shear and flexural-slip general transformation associated with displacement over bends in faults, describing the theoretical framework which we have implemented in the associated program, fbfFor. We show the utility of this kinematic approach by matching seismic reflection examples, analog models, and mechanical models of fault-bend folds to create progressive, balanced kinematic interpretations and gain further insight into the formation of these structures. © 2020 The Author(s)
    • Native mass spectrometry reveals the simultaneous binding of lipids and zinc to rhodopsin

      Norris, Carolanne E.; Keener, James E.; Perera, Suchithranga M.D.C.; Weerasinghe, Nipuna; Fried, Steven D.E.; Resager, William C.; Rohrbough, James G.; Brown, Michael F.; Marty, Michael T.; Department of Chemistry and Biochemistry, University of Arizona; et al. (Elsevier BV, 2021-02)
      Rhodopsin, a prototypical G-protein-coupled receptor, is responsible for scoptic vision at low-light levels. Although rhodopsin's photoactivation cascade is well understood, it remains unclear how lipid and zinc binding to the receptor are coupled. Using native mass spectrometry, we developed a novel data analysis strategy to deconvolve zinc and lipid bound to the proteoforms of rhodopsin and investigated the allosteric interaction between lipids and zinc binding. We discovered that phosphatidylcholine bound to rhodopsin with a greater affinity than phosphatidylserine or phosphatidylethanolamine, and that binding of all lipids was influenced by zinc but with different effects. In contrast, zinc binding was relatively unperturbed by lipids. Overall, these data reveal that lipid binding can be strongly and differentially influenced by metal ions. © 2020 Elsevier B.V.
    • An in situ and morphometric study of maize (Zea mays L.) cob rondel phytoliths from Southwestern North American landraces

      Yost, Chad L.; Michas, McCaela; Adams, Karen R.; Swarts, Kelly; Puseman, Kathryn; Ball, Terry; Department of Geosciences, University of Arizona (Elsevier BV, 2021-02)
      We present the first comprehensive computer-assisted morphometric analysis of microscopic rondel1 phytoliths (plant opal microfossils) produced in the cobs of 24 historic Southwestern North American landraces of maize (Zea mays L.) after all were grown in a well-documented agronomic field study. We also present an in situ study of the location of rondel phytolith production within the maize cob and provide a detailed review of previous maize phytolith studies. We found that glumes contained abundant rondel phytoliths throughout the tissue; however, lemma/palea tissue contained no phytoliths. In contrast, cupule tissue had some areas with abundant phytoliths, some with fewer scattered phytoliths, and vast areas that contained no rondel phytoliths. The rondel-rich areas appear to be where the glumes had once attached to the cupule and may be remnants of glume tissue adhering to the cupule. From the morphometric study, we found there were significant differences in the size morphometries of glume rondels depending on their cob location (top, middle, base) but no significant differences in shape morphometries. Using shape morphometries, we could not discriminate reliably among maize cob rondel phytoliths produced by the diverse landraces considered. The inclusion of morphometrics from areas in addition to or in combination with the outer periclinal surface may allow for some discrimination of maize landraces and is an avenue that should be explored further. Although our approach was not successful at identifying differences between essentially modern landraces, there may be significant rondel phytolith morphometric differences between wild, progenitor, and domesticated Zea.
    • Restoration of a Shrub‐Encroached Semiarid Grassland: Implications for Structural, Hydrologic, and Sediment Connectivity

      Johnson, Justin C.; Williams, C. Jason; Guertin, D. Phillip; Archer, Steven R.; Heilman, Philip; Pierson, Frederick B.; Wei, Haiyan; Univ Arizona, Sch Nat Resources & Environm (Wiley, 2021-01-15)
      Cross‐scale structural and functional connectivity feedbacks can amplify exogenous forces in dryland environments leading to ecosystem state change (e.g. from grassland to shrubland). Attenuation of these connectivity feedbacks would ostensibly be required to restore transitioned ecosystems to their former state. We compared structural, hydrologic, and sediment connectivity on a shrub‐encroached semiarid grassland in southeastern Arizona, USA to that of a nearby site experiencing an increase in non‐native perennial grass (Lehmann lovegrass) abundance 5‐yr following treating shrubs with tebuthiuron herbicide. Soil/vegetation attributes were quantified and paired with hydrologic experiments at fine (0.5 m2) to hillslope (50 m2) scales. Fine‐scale rainfall simulations (120 mm·h‐1 rainfall intensity; 45 min) showed interspaces between shrubs were hydrologically similar on the treated and control sites, whereas herbicided shrub patches were more resource conserving than those within the control (terminal infiltration rates of 105 and 71 mm·h‐1), respectively. High structural connectivity of bare ground (basal gap lengths > 200 cm) was correlated with increased concentrated flow runoff and accompanied by greater sediment yields within the untreated site at a coarse scale (~ 9 m2). Hillslope‐scale modeling suggested a divergence between hydrologic and sediment connectivity: runoff from high intensity rainfall was similar between sites, while predicted sediment yield was 44% less within the tebuthiuron‐treated site. Our results indicate (i) hydraulic properties of soils between shrubs are unresponsive to herbicide treatment, (ii) disruption of structural connectivity of these interspaces associated with grass cover increases subsequent to herbicide application attenuated runoff and the energy needed for sediment transport, and (iii) sediment connectivity is reduced by conversion to a novel grassland ecological state.
    • Single-Cavity Three-Color All-Fiber Femtosecond Laser

      Akhoundi, Farhad; Peyghambarian, N.; College of Optical Sciences, The University of Arizona (Institute of Electrical and Electronics Engineers (IEEE), 2021-01-15)
      In this letter, the design and characterization of an all-fiber femtosecond laser is reported that generates three wavelengths at 1030 nm, 1550 nm, and 1900 nm from a single cavity. The cavity is based on Er-doped fiber and it is mode-locked by a fiber coupled saturable absorber mirror. We take advantage of fiber optics nonlinearity to generate 1030 nm and 1900 nm wavelengths which can be amplified using well-known Yb-doped and Tm-doped amplifiers. The third output of the laser can be optimized to generate femtosecond pulses at a wide range of central wavelength from 1700 nm to 2000 nm. Since all three outputs of the laser are being generated from the same cavity, they can be easily synchronized to be used in various pump and probe applications. This approach reduces the size, power consumption and cost of the laser compared to three individual mode-locked cavities. The laser can be packaged in a 20 cm times20 cm times20 cm form factor. © 1989-2012 IEEE.
    • Ulysses' pact or Ulysses' raft: Using pre‐analysis plans in experimental and nonexperimental research

      Janzen, Sarah A.; Michler, Jeffrey D.; Department of Agricultural and Resource Economics, University of Arizona (Wiley, 2021-01-09)
      Economists have recently adopted preanalysis plans in response to concerns about robustness and transparency in research. The increased use of registered preanalysis plans has raised competing concerns that detailed plans are costly to create, overly restrictive, and limit the type of inspiration that stems from exploratory analysis. We consider these competing views of preanalysis plans, and make a careful distinction between the roles of preanalysis plans and registries, which provide a record of all planned research. We propose a flexible “packraft” preanalysis plan approach that offers benefits for a wide variety of experimental and nonexperimental applications in applied economics.
    • Enriching Lives: How Spending Time with Pets is Related to the Experiential Well-Being of Older Americans

      Kalenkoski, Charlene M.; Korankye, Thomas; Personal and Family Financial Planning, Norton School of Family and Consumer Sciences, The University of Arizona (Springer Science and Business Media LLC, 2021-01-08)
      This study examines how caring for pets and walking, exercising, or playing with pets is associated with the experiential well-being of older Americans using activity-episode-level data from the 2010, 2012, and 2013 American Time Use Surveys (ATUS) and their associated Well-Being Modules (WBM). Estimating a series of ordered probit models that relate various measures of experiential well-being to different measures of pet-related activities, the results show that caring for pets is associated with greater meaning than other activities, controlling for a standard set of demographic and other person-level characteristics. Walking, exercising, or playing with household pets or animals is associated with greater happiness and meaning and less stress relative to other activities. The results from sensitivity analyses show that the magnitudes of the associations for people who live alone are larger than for those who live with others. © 2021, The International Society for Quality-of-Life Studies (ISQOLS) and Springer Nature B.V.
    • Distributed Branch Points and the Shape of Elastic Surfaces with Constant Negative Curvature

      Shearman, Toby L.; Venkataramani, Shankar C.; Department of Mathematics, University of Arizona (Springer Science and Business Media LLC, 2021-01-07)
      We develop a theory for distributed branch points and investigate their role in determining the shape and influencing the mechanics of thin hyperbolic objects. We show that branch points are the natural topological defects in hyperbolic sheets, they carry a topological index that gives them a degree of robustness, and they can influence the overall morphology of a hyperbolic surface without concentrating energy. We develop a discrete differential geometric approach to study the deformations of hyperbolic objects with distributed branch points. We present evidence that the maximum curvature of surfaces with geodesic radius R containing branch points grow sub-exponentially, 𝑂(𝑒𝑐𝑅√) in contrast to the exponential growth 𝑂(𝑒𝑐′𝑅) for surfaces without branch points. We argue that to optimize norms of the curvature, i.e., the bending energy, distributed branch points are energetically preferred in sufficiently large pseudospherical surfaces. Further, they are distributed so that they lead to fractal-like recursive buckling patterns.
    • Research ethics beyond the IRB: Selection bias and the direction of innovation in applied economics

      Michler, Jeffrey D.; Masters, William A.; Josephson, Anna; Department of Agricultural and Resource Economics, University of Arizona (Wiley, 2021-01-07)
      Principles for ethical behavior in the context of research are codified into rules that may change over time to meet peoples’ needs in specific institutions, including universities and professional associations. This paper aims to spark discussion about a set of ethical choices beyond those addressed by an IRB or recent association policy statements. Our specific focus is topic selection and the role of researchers’ interests and incentives in determining the kinds of research that we do. Using the principle of induced innovation, we show how changing incentives can influence the direction of research effort and thereby affect the kinds of policies or technologies that are supported by available evidence. With this paper, we hope to generate discussion among applied economists about selection bias in research and how we can use insights from economics itself to guide topic selection.
    • Methodological Approaches Frame Insights into Endophyte Richness and Community Composition

      Oita, Shuzo; Carey, Jamison; Kline, Ian; Ibáñez, Alicia; Yang, Nathaniel; Hom, Erik F. Y.; Carbone, Ignazio; U’Ren, Jana M.; Arnold, A. Elizabeth; School of Plant Sciences, University of Arizona; et al. (Springer Science and Business Media LLC, 2021-01-07)
      Isolating microbes is vital to study microbiomes, but insights into microbial diversity and ecology can be constrained by recalcitrant or unculturable strains. Culture-free methods (e.g., next-generation sequencing, NGS) have become popular in part because they detect greater richness than culturing alone. Both approaches are used widely to characterize microfungi within healthy leaves (foliar endophytes), but methodological differences among studies can constrain large-scale insights into endophyte ecology. We examined endophytes in a temperate plant community to quantify how certain methodological factors, such as the choice of cultivation media for culturing and storage period after leaf collection, affect inferences regarding endophyte communities; how such effects vary among plant taxa; and how complementary culturing and NGS can be when subsets of the same plant tissue are used for each. We found that endophyte richness and composition from culturing were consistent across five media types. Insights from culturing and NGS were largely robust to differences in storage period (1, 5, and 10 days). Although endophyte richness, composition, and taxonomic diversity identified via culturing vs. NGS differed markedly, both methods revealed host-structured communities. Studies differing only in cultivation media or storage period thus can be compared to estimate endophyte richness, composition, and turnover at scales larger than those of individual studies alone. Our data show that it is likely more important to sample more host species, rather than sampling fewer species more intensively, to quantify endophyte diversity in given locations, with the richest insights into endophyte ecology emerging when culturing and NGS are paired. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.
    • Accumulation of toxic elements in soil and date palm (Phoenix dactylifera L.) through fertilizer application

      Sulaiman, Mohsin; Purayil, Fayas Thayale; Krishankumar, Sonu; Kurup, Shyam S.; Pessarakli, Mohammad; School of Plant Sciences, College of Agriculture and Life Sciences, University of Arizona (Informa UK Limited, 2021-01-05)
      Dates are the staple food for Arabs as well as the major export crop in the Middle East. In this work, we analyzed the concentration of toxic elements in commonly used fertilizers and evaluated metal accumulation in soil and date palm. Different types of fertilizers randomly selected from fertilizer dealers in the UAE were investigated for their toxic metals. Soil and plant samples collected from continuously fertilized date plantations were analyzed. Sandy loam soil (0–30 cm) samples were collected from date palm plantations continuously fertilized for more than 10 years (11 samples) and unfertilized date palm plantations (11 samples). A significant increase in chromium (Cr) and cadmium (Cd) was observed in the leaves of the fertilized date palms, whereas, in date palm fruits, the concentration of copper (Cu) was higher. A distinct correlation was observed between the total and the available metal concentrations in the soil for Cd and Cu. The average concentrations of toxic metals, however, remained within the limits of those used worldwide. It is important to encourage manufacturers to indicate the concentrations of toxic elements on the fertilizer labels due to environmental and health implications. © 2020 Taylor & Francis Group, LLC.
    • A multimillennial snow water equivalent reconstruction from giant sequoia tree rings

      Touchan, R.; Black, B.; Shamir, E.; Hughes, M. K.; Meko, D. M.; Laboratory of Tree‐Ring Research, University of Arizona (Springer Science and Business Media LLC, 2021-01-02)
      The first dendroclimatic reconstruction of May 1 snow water equivalent (SWE) was developed from a Sequoiadendron giganteum regional tree-ring chronology network of 23 sites in central California for the period 90–2012 CE. The reconstruction is based on a significant relationship between May 1 SWE and tree-ring growth and shows climate variability from interannual to intercentennial time scales. A regression-based reconstruction equation explains up to 55% of the variance of SWE for 1940–2012. Split-sample validation supports our use of a reconstruction model based on the full period of reliable observational data (1940–2012). Thresholds for May 1 SWE low (15 percentile) and high (80 percentile) years were selected based on the exploratory scatterplots relationship between observed and reconstructed data for the period 1940–2012. The longest period of consecutive low-SWE years in the reconstruction is 2 years and the frequency of the lowest SWE years is highest during the period 710–809 CE. The longest high-SWE period, defined by consecutive wet years, is 3 years (558–560 CE). SWE and its reconstruction positively correlate with northeastern Pacific sea surface temperatures, the low-frequency variability of which may provide some predictive ability. Ultimately, the instrumental record and reconstruction suggest that unlike other sites in the region, twentieth century SWE variability in these Sequoia groves has remained within historical boundaries and relatively buffered from extremes and severe declines, though this is likely to change in coming decades with potentially negative effects on water availability for these trees. © 2021, Springer-Verlag GmbH Germany, part of Springer Nature.