• 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
    • Unanticipated events, perceptions, and household labor allocation in Zimbabwe

      Josephson, Anna; Shively, Gerald E.; University of Arizona (Elsevier BV, 2021-05)
      This paper investigates labor allocation as a strategy for coping with unanticipated events. We evaluate household responses to unforeseen death and rainfall shocks in Zimbabwe, during a period in which many households were already stressed due to the country's long-term economic crisis. In this context, shocks compound existing stresses. Different types of shocks disparately affect household labor allocation. Household perceptions about the shocks experienced also shift labor use. Perceived rainfall shocks positively affect the share of labor allocated to migration-related activities and negatively affect the share of labor allocated to non-participation. © 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.
    • An elastoplastic solution to undrained expansion of a cylindrical cavity in SANICLAY under plane stress condition

      Li, Lin; Chen, Haohua; Li, Jingpei; Sun, De'an; Department of Civil and Architectural Engineering and Mechanics, The University of Arizona (Elsevier BV, 2021-04)
      Although cylindrical cavity expansion under plane stress condition is commonly encountered in geotechnical problems, most currently available solutions have been developed for cavity expansion under plane strain condition. This paper develops a novel elastoplastic solution for undrained expansion of a cylindrical cavity in SANICLAY under plane stress condition. The SANICLAY model, which could well represent the mechanical behaviour of the anisotropic soil and overconsolidated soil, is employed in the present solution to model the responses of the soil around the expanded cavity. The problem is formulated as a system of first-order differential equations with the unknown variables as the functions of an auxiliary coordinate, which are solved as an initial value problem. The expansion responses under plane stress condition are comprehensively compared with those under plane stress condition to highlight the unique expansion responses under plane stress condition. The results show that the present solution could well reflect the unique expansion responses under plane stress condition, which are totally different from those under plane strain condition. It is expected the proposed solution could provide a reasonable approach to interpret the pressuremeter test and model pile installation effects near the surface of the natural anisotropic clays.
    • FEAST of biosensors: Food, environmental and agricultural sensing technologies (FEAST) in North America

      McLamore, Eric S.; Alocilja, Evangelyn; Gomes, Carmen; Gunasekaran, Sundaram; Jenkins, Daniel; Datta, Shoumen P.A.; Li, Yanbin; Mao, Yu (Jessie); Nugen, Sam R.; Reyes-De-Corcuera, José I.; et al. (Elsevier BV, 2021-04)
      We review the challenges and opportunities for biosensor research in North America aimed to accelerate translational research. We call for platform approaches based on: i) tools that can support interoperability between food, environment and agriculture, ii) open-source tools for analytics, iii) algorithms used for data and information arbitrage, and iv) use-inspired sensor design. We summarize select mobile devices and phone-based biosensors that couple analytical systems with biosensors for improving decision support. Over 100 biosensors developed by labs in North America were analyzed, including lab-based and portable devices. The results of this literature review show that nearly one quarter of the manuscripts focused on fundamental platform development or material characterization. Among the biosensors analyzed for food (post-harvest) or environmental applications, most devices were based on optical transduction (whether a lab assay or portable device). Most biosensors for agricultural applications were based on electrochemical transduction and few utilized a mobile platform. Presently, the FEAST of biosensors has produced a wealth of opportunity but faces a famine of actionable information without a platform for analytics. © 2021 Elsevier B.V.
    • 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.
    • 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
    • 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.
    • 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.
    • A reporting format for leaf-level gas exchange data and metadata

      Ely, Kim S.; Rogers, Alistair; Agarwal, Deborah A.; Ainsworth, Elizabeth A.; Albert, Loren P.; Ali, Ashehad; Anderson, Jeremiah; Aspinwall, Michael J.; Bellasio, Chandra; Bernacchi, Carl; et al. (Elsevier BV, 2021-03)
      Leaf-level gas exchange data support the mechanistic understanding of plant fluxes of carbon and water. These fluxes inform our understanding of ecosystem function, are an important constraint on parameterization of terrestrial biosphere models, are necessary to understand the response of plants to global environmental change, and are integral to efforts to improve crop production. Collection of these data using gas analyzers can be both technically challenging and time consuming, and individual studies generally focus on a small range of species, restricted time periods, or limited geographic regions. The high value of these data is exemplified by the many publications that reuse and synthesize gas exchange data, however the lack of metadata and data reporting conventions make full and efficient use of these data difficult. Here we propose a reporting format for leaf-level gas exchange data and metadata to provide guidance to data contributors on how to store data in repositories to maximize their discoverability, facilitate their efficient reuse, and add value to individual datasets. For data users, the reporting format will better allow data repositories to optimize data search and extraction, and more readily integrate similar data into harmonized synthesis products. The reporting format specifies data table variable naming and unit conventions, as well as metadata characterizing experimental conditions and protocols. For common data types that were the focus of this initial version of the reporting format, i.e., survey measurements, dark respiration, carbon dioxide and light response curves, and parameters derived from those measurements, we took a further step of defining required additional data and metadata that would maximize the potential reuse of those data types. To aid data contributors and the development of data ingest tools by data repositories we provided a translation table comparing the outputs of common gas exchange instruments. Extensive consultation with data collectors, data users, instrument manufacturers, and data scientists was undertaken in order to ensure that the reporting format met community needs. The reporting format presented here is intended to form a foundation for future development that will incorporate additional data types and variables as gas exchange systems and measurement approaches advance in the future. The reporting format is published in the U.S. Department of Energy's ESS-DIVE data repository, with documentation and future development efforts being maintained in a version control system.
    • Twisted moduli spaces and Duistermaat–Heckman measures

      Zerouali, Ahmed J.; University of Arizona, Department of Mathematics (Elsevier BV, 2021-03)
      Following Boalch–Yamakawa, Li-Bland–Ševera and Meinrenken, we consider a certain class of moduli spaces on bordered surfaces from a quasi-Hamiltonian perspective. For a given Lie group G, these character varieties parametrize flat G-connections on “twisted” local systems, in the sense that the transition functions take values in G⋊Aut(G). After reviewing the necessary tools to discuss twisted quasi-Hamiltonian manifolds, we construct a Duistermaat–Heckman (DH) measure on G that is invariant under the twisted conjugation action g↦hgκ(h−1) for κ∈Aut(G), and characterize it by giving a localization formula for its Fourier coefficients. We then illustrate our results by determining the DH measures of our twisted moduli spaces. © 2020 Elsevier B.V.
    • Trash reconsidered: A relational approach to deposition in the Pueblo Southwest

      Fladd, Samantha G.; Hedquist, Saul L.; Adams, E. Charles; School of Anthropology, University of Arizona; Arizona State Museum, University of Arizona (Elsevier BV, 2021-03)
      Deposition creates the archaeological record; however, the social implications of depositional practices are often overlooked, particularly when considering domestic materials found in upper room fill. In this paper, we argue that the term “trash” and its connotations mischaracterize the thought and meaning that motivate decisions about deposition, as exemplified by ethnohistoric and modern accounts of disposal within Pueblo society. Understanding the context and content of deposition can reveal important aspects of the identities, beliefs, and relationships of the individuals and groups who created them. We explore the social role of deposits at Homol'ovi I, an ancestral Hopi pueblo in northeastern Arizona, through detailed analyses of excavation data. Drawing on contemporary Hopi insights, rooms and objects are found to assume distinct social identities, specifically gender, that influence the placement of materials throughout the pueblo. We conclude that patterns of cultural deposition from all contexts have the potential to provide significant insights about the life histories, reuse, and commemoration of spaces and objects when considering archaeological contexts worldwide. © 2021 Elsevier Inc.
    • The concept of responsibility in the ethics of self-defense and war

      Sartorio, Carolina (Springer Science and Business Media LLC, 2021-02-03)
      The focus of this paper is an influential family of views in the ethics of self-defense and war: views that ground the agent’s liability to be attacked in self-defense in the agent’s moral responsibility for the threat posed (“Responsibility Views”). I critically examine the concept of responsibility employed by such views, by looking at potential connections with the contemporary literature on moral responsibility. I start by uncovering some of the key assumptions that Responsibility Views make about the relevant concept of responsibility, and by scrutinizing those assumptions under the lens of more general theorizing about responsibility. I identify an important conflict that arises at that point. The problem is that the concept presupposed by Responsibility Views is in tension with the standard way of understanding the connection between the neutral and non-neutral forms of moral responsibility. I draw attention to a particular strategy that could be used to address this challenge, but I also identify some important obstacles that stand in the way. © 2021, The Author(s), under exclusive licence to Springer Nature B.V. part of Springer Nature.
    • Smartphones and Social Support: Longitudinal Associations Between Smartphone Use and Types of Support

      Lapierre, Matthew A.; Zhao, Pengfei; University of Arizona (SAGE Publications, 2021-02-03)
      Smartphones provide users with a vast array of tools to reach out to the world. Smartphones can be used to reach out interpersonally with family, friends, and acquaintances, they can be used to scroll through social networking platforms where one can post comments on a friend’s status update or read about the personal lives of their favorite celebrity, and they can be used to surf the web or read the news. Yet, research has also shown that problematic smartphone use (PSU) can be harmful. Of interest in the current study is whether smartphones can help or harm social bonds longitudinally via social support. Working with a sample of 221 college students who were surveyed twice over a 3-month span, this study explored whether various types of smartphone use (e.g., person-to-person, social networking, and mass-mediated) along with PSU predicted different types of social support over time. The results showed that person-to-person smartphone use was associated with greater belonging support (i.e., feeling accepted by people around you) and tangible support (i.e., feeling that you can find people to help with practical needs) over time. In addition, increased PSU was associated with less tangible support longitudinally. Lastly, there were no effects for social networking or mass-mediated smartphone use on any type of social support. These results offer important insights into how smartphones potentially affect our ability to connect with others along with greater detail about specific kinds of use are implicated. © The Author(s) 2021.
    • 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.
    • Constructing a desert labyrinth: The psychological and emotional geographies of deterrence strategy on the U.S. / Mexico border

      Chambers, Samuel N.; Boyce, Geoffrey Alan; Jacobs, W. Jake; School of Geography, Development & Environment, The University of Arizona; Department of Psychology, The University of Arizona (Elsevier BV, 2021-02)
      Confinement, hindrance, and time bring anxiety, fear, and stress, often accompanied by confusion and desperation. In the case of undocumented immigrants in the Sonoran Desert, such conditions are manipulated by way of surveillance and policing. These conditions, in combination with physical exertion, augment a physiological stress response that coalesces with existing traumas and fear. We undertake a critical mapping of relations among enforcement infrastructure, migration routes, and measurable features of the physical landscape to demonstrate that a corridor in the region functions as a labyrinth, an outcome of a combination of threats and stressors determined by the spaces migrants find themselves in after crossing the U.S./Mexico border. We argue a biopolitical understanding of current border policies indicates it reduces migrants to bare life rather than using threat, stressors, or trauma as instruments for manipulating behavior. We discuss how this labyrinth works in combination with other mechanisms, including criminalization, detention, abuse, separation, and deportation, to deliver consequences that may deter migration. Despite these efforts, migration routes remain plastic, indicating the continued potential to resist and evade the surveillance technologies and enforcement deployed in the borderlands. We assert that an inevitable result of the desert labyrinth is human mortality. © 2021 Elsevier Ltd