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  • High-resolution spectroscopy of SN 2017hcc and its blueshifted line profiles from post-shock dust formation

    Smith, Nathan; Andrews, Jennifer E; Steward Observatory, University of Arizona (Oxford University Press, 2020-10-09)
    SN 2017hcc was remarkable for being a nearby and strongly polarized superluminous Type IIn supernova (SN). We obtained high-resolution Echelle spectra that we combine with other spectra to investigate its line-profile evolution. All epochs reveal narrow P Cygni components from pre-shock circumstellar material (CSM), indicating an axisymmetric outflow from the progenitor of 40-50 km s−1. Broad and intermediate-width components exhibit the classic evolution seen in luminous SNe IIn: symmetric Lorentzian profiles from pre-shock CSM lines broadened by electron scattering at early times, transitioning at late times to multicomponent, irregular profiles coming from the SN ejecta and post-shock shell. As in many SNe IIn, profiles show a progressively increasing blueshift, with a clear flux deficit in red wings of the intermediate and broad velocity components after day 200. This blueshift develops after the continuum luminosity fades, and in the intermediate-width component, persists at late times even after the SN ejecta fade. In SN 2017hcc, the blueshift cannot be explained as occultation by the SN photosphere, pre-shock acceleration of CSM, or a lopsided explosion of CSM. Instead, the blueshift arises from dust formation in the post-shock shell and in the SN ejecta. The effect has a wavelength dependence characteristic of dust, exhibiting an extinction law consistent with large grains. Thus, SN 2017hcc experienced post-shock dust formation and had a mildly bipolar CSM shell, similar to SN 2010jl. Like other superluminous SNe IIn, the progenitor lost around 10 M☉ due to extreme eruptive mass-loss in the decade before exploding. © 2020 The Author(s)
  • Eigenspectra: a framework for identifying spectra from 3D eclipse mapping

    Mansfield, Megan; Schlawin, Everett; Lustig-Yaeger, Jacob; Adams, Arthur D; Rauscher, Emily; Arcangeli, Jacob; Feng, Y Katherina; Gupta, Prashansa; Keating, Dylan; Stevenson, Kevin B; et al. (Oxford University Press, 2020-10-15)
    Planetary atmospheres are inherently 3D objects that can have strong gradients in latitude, longitude, and altitude. Secondary eclipse mapping is a powerful way to map the 3D distribution of the atmosphere, but the data can have large correlations and errors in the presence of photon and instrument noise. We develop a technique to mitigate the large uncertainties of eclipse maps by identifying a small number of dominant spectra to make them more tractable for individual analysis via atmospheric retrieval. We use the eigencurves method to infer a multiwavelength map of a planet from spectroscopic secondary eclipse light curves. We then apply a clustering algorithm to the planet map to identify several regions with similar emergent spectra. We combine the similar spectra together to construct an 'eigenspectrum' for each distinct region on the planetary map. We demonstrate how this approach could be used to isolate hot from cold regions and/or regions with different chemical compositions in observations of hot Jupiters with the James Webb Space Telescope (JWST). We find that our method struggles to identify sharp edges in maps with sudden discontinuities, but generally can be used as a first step before a more physically motivated modelling approach to determine the primary features observed on the planet. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
  • Combinatorial Biosynthesis of Sulfated Benzenediol Lactones with a Phenolic Sulfotransferase from Fusarium graminearum PH-1

    Xie, Linan; Xiao, Dongliang; Wang, Xiaojing; Wang, Chen; Bai, Jing; Yue, Qun; Yue, Haitao; Li, Ye; Molnár, István; Xu, Yuquan; et al. (American Society for Microbiology, 2020-11-25)
    Total biosynthesis or whole-cell biocatalytic production of sulfated small molecules relies on the discovery and implementation of appropriate sulfotransferase enzymes. Although fungi are prominent biocatalysts and have been used to sulfate drug-like phenolics, no gene encoding a sulfotransferase enzyme has been functionally characterized from these organisms. Here, we identify a phenolic sulfotransferase, FgSULT1, by genome mining from the plant-pathogenic fungus Fusarium graminearum PH-1. We expressed FgSULT1 in a Saccharomyces cerevisiae chassis to modify a broad range of benzenediol lactones and their nonmacrocyclic congeners, together with an anthraquinone, with the resulting unnatural natural product (uNP) sulfates displaying increased solubility. FgSULT1 shares low similarity with known animal and plant sulfotransferases. Instead, it forms a sulfotransferase family with putative bacterial and fungal enzymes for phase II detoxification of xenobiotics and allelochemicals. Among fungi, putative FgSULT1 homologues are encoded in the genomes of Fusarium spp. and a few other genera in nonsyntenic regions, some of which may be related to catabolic sulfur recycling. Computational structure modeling combined with site-directed mutagenesis revealed that FgSULT1 retains the key catalytic residues and the typical fold of characterized animal and plant sulfotransferases. Our work opens the way for the discovery of hitherto unknown fungal sulfotransferases and provides a synthetic biological and enzymatic platform that can be adapted to produce bioactive sulfates, together with sulfate ester standards and probes for masked mycotoxins, precarcinogenic toxins, and xenobiotics.IMPORTANCE Sulfation is an expedient strategy to increase the solubility, bioavailability, and bioactivity of nutraceuticals and clinically important drugs. However, chemical or biological synthesis of sulfoconjugates is challenging. Genome mining, heterologous expression, homology structural modeling, and site-directed mutagenesis identified FgSULT1 of Fusarium graminearum PH-1 as a cytosolic sulfotransferase with the typical fold and active site architecture of characterized animal and plant sulfotransferases, despite low sequence similarity. FgSULT1 homologues are sparse in fungi but form a distinct clade with bacterial sulfotransferases. This study extends the functionally characterized sulfotransferase superfamily to the kingdom Fungi and demonstrates total biosynthetic and biocatalytic synthetic biological platforms to produce unnatural natural product (uNP) sulfoconjugates. Such uNP sulfates may be utilized for drug discovery in human and veterinary medicine and crop protection. Our synthetic biological methods may also be adapted to generate masked mycotoxin standards for food safety and environmental monitoring applications and to expose precarcinogenic xenobiotics.
  • Concordance cosmology?

    Park, Youngsoo; Rozo, Eduardo; Department of Physics, University of Arizona (Oxford University Press, 2020-09-01)
    We propose a new intuitive metric for evaluating the tension between two experiments, and apply it to several data sets. While our metric is non-optimal, if evidence of tension is detected, this evidence is robust and easy to interpret. Assuming a flat Lambda cold dark matter (ΛCDM) cosmological model, we find that there is a modest 2.2σ tension between the Dark Energy Survey (DES) Year 1 results and the Planck measurements of the cosmic microwave background. This tension is driven by the difference between the amount of structure observed in the late-time Universe and that predicted from fitting the Planck data, and appears to be unrelated to the tension between Planck and local estimates of the Hubble rate. In particular, combining DES, baryon acoustic oscillations, big bang nucleosynthesis, and supernovae measurements recover a Hubble constant and sound horizon consistent with Planck, and in tension with local distance-ladder measurements. If the tension between these various data sets persists, it is likely that reconciling all current data will require breaking the flat ΛCDM model in at least two different ways: one involving new physics in the early Universe, and one involving new late-time Universe physics. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
  • The Universe at z > 10: predictions for JWST from the universemachine DR1

    Behroozi, Peter; Conroy, Charlie; Wechsler, Risa H; Hearin, Andrew; Williams, Christina C; Moster, Benjamin P; Yung, L Y Aaron; Somerville, Rachel S; Gottlöber, Stefan; Yepes, Gustavo; et al. (Oxford University Press, 2020-10-14)
    The James Webb Space Telescope (JWST) is expected to observe galaxies at z > 10 that are presently inaccessible. Here, we use a self-consistent empirical model, the universemachine, to generate mock galaxy catalogues and light-cones over the redshift range z = 0-15. These data include realistic galaxy properties (stellar masses, star formation rates, and UV luminosities), galaxy-halo relationships, and galaxy-galaxy clustering. Mock observables are also provided for different model parameters spanning observational uncertainties at z < 10. We predict that Cycle 1 JWST surveys will very likely detect galaxies with M∗ > 107 M· and/or M1500 < -17 out to at least z ∼13.5. Number density uncertainties at z > 12 expand dramatically, so efforts to detect z > 12 galaxies will provide the most valuable constraints on galaxy formation models. The faint-end slopes of the stellar mass/luminosity functions at a given mass/luminosity threshold steepen as redshift increases. This is because observable galaxies are hosted by haloes in the exponentially falling regime of the halo mass function at high redshifts. Hence, these faint-end slopes are robustly predicted to become shallower below current observable limits (M∗ < 107 M· or M1500 > -17). For reionization models, extrapolating luminosity functions with a constant faint-end slope from M1500 = -17 down to M1500 = -12 gives the most reasonable upper limit for the total UV luminosity and cosmic star formation rate up to z ∼12. We compare to three other empirical models and one semi-analytic model, showing that the range of predicted observables from our approach encompasses predictions from other techniques. Public catalogues and light-cones for common fields are available online. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
  • Measurement Recorder: developing a useful tool for making species descriptions that produces computable phenotypes

    Cui, Hong; Zhang, Limin; Ford, Bruce; Cheng, Hsin-Liang; Macklin, James A; Reznicek, Anton; Starr, Julian; School of Information, University of Arizona (Oxford University Press, 2020-11-20)
    To use published phenotype information in computational analyses, there have been efforts to convert descriptions of phenotype characters from human languages to ontologized statements. This postpublication curation process is not only slow and costly, it is also burdened with significant intercurator variation (including curator-author variation), due to different interpretations of a character by various individuals. This problem is inherent in any human-based intellectual activity. To address this problem, making scientific publications semantically clear (i.e. computable) by the authors at the time of publication is a critical step if we are to avoid postpublication curation. To help authors efficiently produce species phenotypes while producing computable data, we are experimenting with an author-driven ontology development approach and developing and evaluating a series of ontology-aware software modules that would create publishable species descriptions that are readily useable in scientific computations. The first software module prototype called Measurement Recorder has been developed to assist authors in defining continuous measurements and reported in this paper. Two usability studies of the software were conducted with 22 undergraduate students majoring in information science and 32 in biology. Results suggest that participants can use Measurement Recorder without training and they find it easy to use after limited practice. Participants also appreciate the semantic enhancement features. Measurement Recorder's character reuse features facilitate character convergence among participants by 48% and have the potential to further reduce user errors in defining characters. A set of software design issues have also been identified and then corrected. Measurement Recorder enables authors to record measurements in a semantically clear manner and enriches phenotype ontology along the way. Future work includes representing the semantic data as Resource Description Framework (RDF) knowledge graphs and characterizing the division of work between authors as domain knowledge providers and ontology engineers as knowledge formalizers in this new author-driven ontology development approach. © The Author(s) 2020. Published by Oxford University Press.
  • Spatial Fingerprint of Younger Dryas Cooling and Warming in Eastern North America

    Fastovich, David; Russell, James M.; Jackson, Stephen T.; Krause, Teresa R.; Marcott, Shaun A.; Williams, John W.; Department of Geosciences, University of Arizona (Blackwell Publishing Ltd, 2020-10-22)
    The Younger Dryas (YD, 12.9–11.7 ka) is the most recent, near-global interval of abrupt climate change with rates similar to modern global warming. Understanding the causes and biodiversity effects of YD climate changes requires determining the spatial fingerprints of past temperature changes. Here we build pollen-based and branched glycerol dialkyl glycerol tetraether-based temperature reconstructions in eastern North America (ENA) to better understand deglacial temperature evolution. YD cooling was pronounced in the northeastern United States and muted in the north central United States. Florida sites warmed during the YD, while other southeastern sites maintained a relatively stable climate. This fingerprint is consistent with an intensified subtropical high during the YD and demonstrates that interhemispheric responses were more complex spatially in ENA than predicted by the bipolar seesaw model. Reduced-amplitude or antiphased millennial-scale temperature variability in the southeastern United States may support regional hotspots of biodiversity and endemism. © 2020. The Authors.
  • Poleward Excursions by the Himalayan Subtropical Jet Over the Past Four Centuries

    Thapa, U. K.; St. George, S.; Trouet, V.; Laboratory of Tree-Ring Research, University of Arizona (Blackwell Publishing Ltd, 2020-10-29)
    Since the 1980s, the subtropical jet stream has generally moved poleward, but its behavior varies by region and season. Here we examine the interannual variability and trends in the latitudinal position of the spring subtropical jet over the Himalayas. During the modern period (1948 to 2018), the spring (March-April-May) jet is typically anchored immediately south of the Himalayas but has rarely (in 1956, 1971, 1984, and 1999) moved poleward to pass over Kyrgyzstan and northwest China. A tree-ring reconstruction of the jet's latitude indicates that such poleward excursions may have become more frequent after 1950, but it is not clear whether that behavior is unprecedented within the past four centuries. These insights into the behavior of the Himalayan subtropical jet may improve seasonal weather forecasts for the region and provide a target for climate simulations to test whether the recent spate of excursions is unusual and due to anthropogenic warming. ©2020. American Geophysical Union. All Rights Reserved.
  • Exploring Community Psychosocial Stress Related to Per- and Poly-Fluoroalkyl Substances (PFAS) Contamination: Lessons Learned from a Qualitative Study

    Calloway, Eric E; Chiappone, Alethea L; Schmitt, Harrison J; Sullivan, Daniel; Gerhardstein, Ben; Tucker, Pamela G; Rayman, Jamie; Yaroch, Amy L; Department of Psychology, University of Arizona (MDPI AG, 2020-11-24)
    The purpose of this study was to qualitatively explore the per- and poly-fluoroalkyl substances (PFAS) exposure experience and associated stressors, to inform public health efforts to support psychosocial health and resilience in affected communities. Semi-structured interviews (n = 9) were conducted from July-September 2019 with community members and state public health department representatives from areas with PFAS-contaminated drinking water. Thematic analysis was completed and themes were described and summarized. Reported stressors included health concerns and uncertainty, institutional delegitimization and associated distrust, and financial burdens. Interviewees provided several strategies to reduce stress and promote stress coping capacity and resilience, including showing empathy and validating the normalcy of experiencing stress; building trust through visible action and sustained community engagement; providing information and actionable guidance; discussing stress carefully; fostering stress coping capacity and resilience with opportunities to build social capital and restore agency; and building capacity among government agencies and health care providers to address psychosocial stress. While communities affected by PFAS contamination will face unavoidable stressors, positive interactions with government responders and health care providers may help reduce negative stress. More research on how best to integrate community psychosocial health and stress coping and resilience concepts into the public health response to environmental contamination could be helpful in addressing these stressors.
  • Component properties and mutual orbit of binary main-belt comet 288P/(300163) 2006 VW139

    Agarwal, J.; Kim, Y.; Jewitt, D.; Mutchler, M.; Weaver, H.; Larson, S.; Lunar and Planetary Laboratory, University of Arizona (EDP Sciences, 2020-11-19)
    The binary asteroid 288P/(300163) is unusual both for its combination of wide-separation and high mass ratio and for its comet-like activity. It is not currently known whether there is a causal connection between the activity and the unusual orbit or if instead the activity helped to overcome a strong detection bias against such sub-arcsecond systems. Aims. We aim to find observational constraints discriminating between possible formation scenarios and to characterise the physical properties of the system components. Methods. We measured the component separation and brightness using point spread function fitting to high-resolution Hubble Space Telescope/Wide Field Camera 3 images from 25 epochs between 2011 and 2020.We constrained component sizes and shapes from the photometry, and we fitted a Keplerian orbit to the separation as a function of time. Results. Approximating the components A and B as prolate spheroids with semi-axis lengths a < b and assuming a geometric albedo of 0.07, we find aA 0.6 km, bA 1.4 km, aB 0.5 km, and bB 0.8 km.We find indications that the dust production may have concentrated around B and that the mutual orbital period may have changed by 1-2 days during the 2016 perihelion passage. Orbit solutions have semi-major axes in the range of (105-109) km, eccentricities between 0.41 and 0.51, and periods of (117.3-117.5) days preperihelion and (118.5-119.5) days post-perihelion, corresponding to system masses in the range of (6.67-7.23) 1012 kg. The mutual and heliocentric orbit planes are roughly aligned. Conclusions. Based on the orbit alignment, we infer that spin-up of the precursor by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect led to the formation of the binary system. We disfavour (but cannot exclude) a scenario of very recent formation where activity was directly triggered by the break-up, because our data support a scenario with a single active component. © J. Agarwal et al. 2020.
  • A data-driven approach to constraining the atmospheric temperature structure of the ultra-hot Jupiter KELT-9b

    Fossati, L.; Shulyak, D.; Sreejith, A. G.; Koskinen, T.; Young, M. E.; Cubillos, P. E.; Lara, L. M.; France, K.; Rengel, M.; Cauley, P. W.; et al. (EDP Sciences, 2020-11-13)
    Context. Observationally constraining the atmospheric temperature-pressure (TP) profile of exoplanets is an important step forward for improving planetary atmosphere models, thus further enabling one to place the detection of spectral features and the measurement of atomic and molecular abundances through transmission and emission spectroscopy on solid ground. Aims. The aim is to constrain the TP profile of the ultra-hot Jupiter KELT-9b by fitting synthetic spectra to the observed Hα and Hβ lines and identify why self-consistent planetary TP models are unable to fit the observations. Methods. We constructed 126 one-dimensional TP profiles varying the lower and upper atmospheric temperatures, as well as the location and gradient of the temperature rise. For each TP profile, we computed the transmission spectra of the Hα and Hβ lines employing the Cloudy radiative transfer code, which self-consistently accounts for non-local thermodynamic equilibrium (NLTE) effects. Results. The TP profiles, leading to best fit the observations, are characterised by an upper atmospheric temperature of 10 000-11 000 K and by an inverted temperature profile at pressures higher than 10-4 bar. We find that the assumption of local thermodynamic equilibrium (LTE) leads one to overestimate the level population of excited hydrogen by several orders of magnitude and hence to significantly overestimate the strength of the Balmer lines. The chemical composition of the best fitting models indicate that the high upper atmospheric temperature is most likely driven by metal photoionisation and that FeII and FeIII have comparable abundances at pressures lower than 10-6 bar, possibly making the latter detectable. Conclusions. Modelling the atmospheres of ultra-hot Jupiters requires one to account for metal photoionisation. The high atmospheric mass-loss rate (>1011 g s-1), caused by the high temperature, may have consequences on the planetary atmospheric evolution. Other ultra-hot Jupiters orbiting early-type stars may be characterised by similarly high upper atmospheric temperatures and hence high mass-loss rates. This may have consequences on the basic properties of the observed planets orbiting hot stars. © ESO 2020.
  • Source Apportionment of Aerosol at a Coastal Site and Relationships with Precipitation Chemistry: A Case Study over the Southeast United States

    Corral, Andrea F.; Dadashazar, Hossein; Stahl, Connor; Edwards, Eva-Lou; Zuidema, Paquita; Sorooshian, Armin; Department of Chemical and Environmental Engineering, The University of Arizona; Department of Hydrology and Atmospheric Sciences, The University of Arizona (MDPI AG, 2020-11-10)
    This study focuses on the long-term aerosol and precipitation chemistry measurements from colocated monitoring sites in Southern Florida between 2013 and 2018. A positive matrix factorization (PMF) model identified six potential emission sources impacting the study area. The PMF model solution yielded the following source concentration profiles: (i) combustion; (ii) fresh sea salt; (iii) aged sea salt; (iv) secondary sulfate; (v) shipping emissions; and (vi) dust. Based on these results, concentration-weighted trajectory maps were developed to identify sources contributing to the PMF factors. Monthly mean precipitation pH values ranged from 4.98 to 5.58, being positively related to crustal species and negatively related to SO42-. Sea salt dominated wet deposition volume-weighted concentrations year-round without much variability in its mass fraction in contrast to stronger seasonal changes in PM2.5 composition where fresh sea salt was far less influential. The highest mean annual deposition fluxes were attributed to Cl-, NO3-, SO42-, and Na+ between April and October. Nitrate is strongly correlated with dust constituents (unlike sea salt) in precipitation samples, indicative of efficient partitioning to dust. Interrelationships between precipitation chemistry and aerosol species based on long-term surface data provide insight into aerosol-cloud-precipitation interactions.
  • Protocol for the REPAT study: role of emotional processing in art therapy for breast cancer palliative care patients

    Czamanski-Cohen, Johanna; Wiley, Joshua; Weihs, KL; Department of Psychiatry College of Medicine, University of Arizona (BMJ Publishing Group, 2020-11-19)
    Introduction Patients with breast cancer (BC) cope with depression which is linked to functional limitations in survivorship and to physical symptoms. Pain and fatigue are prominent symptoms that affect the well-being of cancer survivors. Emotional processing has been associated with improved physical and psychological health in survivors. Art therapy is a form of psychotherapy that involves the use of visual art-making for expression and communication. It encourages emotional processing and has been linked to symptom reduction in patients with cancer. This protocol is designed to examine two mechanistic changes: Emotional processing (awareness, expression and acceptance) and cholinergic anti-inflammatory processes (heart rate variability and cytokine expression) through which an art therapy intervention may reduce depression, pain and fatigue. In addition, we will examine ethnocultural differences in the effect of art therapy in women from different ethnocultural backgrounds. Methods and analysis A randomised controlled study with careful controls will randomise 240 patient with BC (50% Jewish and 50% Arab) to an 8-week group art therapy intervention or an 8-week Mandala colouring comparison group. This design will test the mechanisms of art therapy on the targeted outcomes beyond the effects of time with a group, focus on a task and engagement with art materials. We will examine two potential mechanisms: Emotional processing and cholinergic anti-inflammatory processes; of the intervention effects on depression, pain and fatigue and compare these effects in Arab versus Jewish women. Ethics and dissemination Participants will sign informed consent before participation and will be informed that they can leave the study at any point in time without effect on their medical treatment. The Helsinki committees of each participating hospital have approved the study. Data collected in this study will be published in peer-review journals, and we will use the platform of the study website (http://repat.haifa.ac.il/en/) for further dissemination to the general public. © 2020 Author(s). Published by BMJ.
  • Evaluation of policy scenarios for water resources planning and management in an arid region

    Mohamed, Mohamed M.; El-Shorbagy, Walid; Kizhisseri, Mohamed I.; Chowdhury, Rezaul; McDonald, Adrian; Civil and Architectural Engineering and Mechanics, University of Arizona (Elsevier B.V., 2020-11-29)
    Study region: Abu Dhabi, United Arab Emirates (UAE) Study focus: Water demand in the Emirate of Abu Dhabi (EAD) has increased significantly over the last few decades. Hence, a main challenge for the EAD water policy makers is to develop long-term resilient water resources strategies. This study evaluates future water supply-demand condition in the EAD and identifies water management strategies that support a sustainable future. A dynamic water budget modelling framework is used to evaluate future water demand as affected by population growth, economic growth, proposed water related policies, consumption patterns, and climate change. The Abu Dhabi Dynamic Water Budget Model (ADWBM) is used to construct future water scenarios and assess the status of the EAD water system until 2050 in terms of water supply-demand balance. This study presents four suites of water scenarios, namely: Business as Usual (BAU), Policy First (PF), Sustainability by Conservation (SC), and Rainfall Enhanced Sustainability (RES) scenarios. New hydrological insights: Simulation results indicate that both SC and RES scenarios achieved balanced water budget without any shortage throughout the entire period until 2050. The RES scenario is recommended for adoption because of the reasonable and achievable proposed consumption reductions needed in the different demand sectors. The obtained results should be valuable for devising appropriate strategies to prevent potential future water shortages in the Emirate. © 2020 The Authors
  • Indemnifying precaution: economic insights for regulation of a highly infectious disease

    Robertson, Christopher T; Schaefer, K Aleks; Scheitrum, Daniel; Puig, Sergio; Joiner, Keith; James E. Rogers College of Law, University of Arizona; Department of Agricultural and Resource Economics, University of Arizona; Eller College of Management, University of Arizona (Oxford University Press, 2020-05-30)
    Economic insights are powerful for understanding the challenge of managing a highly infectious disease, such as COVID-19, through behavioral precautions including social distancing. One problem is a form of moral hazard, which arises when some individuals face less personal risk of harm or bear greater personal costs of taking precautions. Without legal intervention, some individuals will see socially risky behaviors as personally less costly than socially beneficial behaviors, a balance that makes those beneficial behaviors unsustainable. For insights, we review health insurance moral hazard, agricultural infectious disease policy, and deterrence theory, but find that classic enforcement strategies of punishing noncompliant people are stymied. One mechanism is for policymakers to indemnify individuals for losses associated with taking those socially desirable behaviors to reduce the spread. We develop a coherent approach for doing so, based on conditional cash payments and precommitments by citizens, which may also be reinforced by social norms.
  • Prophylactic inhibition of NF-κB expression in microglia leads to attenuation of hypoxic ischemic injury of the immature brain

    Zaghloul, Nahla; Kurepa, Dalibor; Bader, Mohammad Y; Nagy, Nadia; Ahmed, Mohamed N; Department of Pediatrics, Division of Neonatology, University of Arizona (BioMed Central Ltd, 2020-12-01)
    Background: Periventricular leukomalacia (PVL), a devastating brain injury affecting premature infants, is the most common cause of cerebral palsy. PVL is caused by hypoxia ischemia (HI) and is characterized by white matter necrotic lesions, microglial activation, upregulation of NF-κB, and neuronal death. The microglia is the main cell involved in PVL pathogenesis. The goal of this study was to investigate the role of microglial NF-κB activity and its prophylactic inhibition in a neonate mouse model of HI. Methods: Transgenic mice with specific knockout NF-κB in microglia and colony stimulating factor 1 receptor Cre with floxed IKKβ (CSF-1R Cre + IKKβflox/wt ) were used. Postnatal day 5 (P5) mice underwent sham or bilateral temporary carotid artery ligation followed by hypoxia. After HI insult, inflammatory cytokines, volumetric MRI, histopathology, and immunohistochemistry for oligodendroglia and microglial activation markers were analyzed. Long-term neurobehavioral assessment, including grip strength, rotarod, and open field testing, was performed at P60. Results: We demonstrate that selective inhibition of NF-κB in microglia decreases HI-induced brain injury by decreasing microglial activation, proinflammatory cytokines, and nitrative stress. Rescue of oligodendroglia is evidenced by immunohistochemistry, decreased ventriculomegaly on MRI, and histopathology. This selective inhibition leads to attenuation of paresis, incoordination, and improved grip strength, gait, and locomotion. Conclusion: We conclude that NF-κb activation in microglia plays a major role in the pathogenesis of hypoxic ischemic injury of the immature brain, and its prophylactic inhibition offers significant neuroprotection. Using a specific inhibitor of microglial NF-κB may offer a new prophylactic or therapeutic alternative in preterm infants affected by HI and possibly other neurological diseases in which microglial activation plays a role. © 2020, The Author(s).
  • Thermal Properties of Bayfol® HX200 Photopolymer

    Blanche, Pierre-Alexandre; Mahamat, Adoum H.; Buoye, Emmanuel; College of Optical Sciences, University of Arizona (MDPI AG, 2020-12-02)
    Bayfol® HX200 photopolymer is a holographic recording material used in a variety of applications such as a holographic combiner for a heads-up display and augmented reality, dispersive grating for spectrometers, and notch filters for Raman spectroscopy. For these systems, the thermal properties of the holographic material are extremely important to consider since temperature can affect the diffraction efficiency of the hologram as well as its spectral bandwidth and diffraction angle. These thermal variations are a consequence of the distance and geometry change of the diffraction Bragg planes recorded inside the material. Because temperatures can vary by a large margin in industrial applications (e.g., automotive industry standards require withstanding temperature up to 125◦C), it is also essential to know at which temperature the material starts to be affected by permanent damage if the temperature is raised too high. Using thermogravimetric analysis, as well as spectral measurement on samples with and without hologram, we measured that the Bayfol® HX200 material does not suffer from any permanent thermal degradation below 160◦C. From that point, a further increase in temperature induces a decrease in transmission throughout the entire visible region of the spectrum, leading to a reduced transmission for an original 82% down to 27% (including Fresnel reflection). We measured the refractive index change over the temperature range from 24◦C to 100◦C. Linear interpolation give a slope 4.5 × 10−4 K−1 for unexposed film, with the extrapolated refractive index at 0◦C equal to n0 = 1.51. This refractive index change decreases to 3 × 10−4 K−1 when the material is fully cured with UV light, with a 0◦C refractive index equal to n0 = 1.495. Spectral properties of a reflection hologram recorded at 532 nm was measured from 23◦C to 171◦C. A consistent 10 nm spectral shift increase was observed for the diffraction peak wavelength when the temperature reaches 171◦C. From these spectral measurements, we calculated a coefficient of thermal expansion (CTE) of 384 × 10−6 K−1 by using the coupled wave theory in order to determine the increase of the Bragg plane spacing with temperature. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
  • Assessing the Food Safety Risk Posed by Birds Entering Leafy Greens Fields in the US Southwest

    Fonseca, Jorge M; Ravishankar, Sadhana; Sanchez, Charles A; Park, Eunhee; Nolte, Kurt D; School of Animal & Comparative Biomedical Sciences, University of Arizona; Maricopa Agricultural Center, Department of Environmental Sciences, The University of Arizona (MDPI AG, 2020-11-24)
    In the US Southwest, it is common to observe birds in leafy green fields, though the risk they contribute to foodborne outbreaks remains unclear. In this study, we investigated and recorded the relationship between birds near leafy green fields and the risk for contaminated irrigation water or leafy green plants. We monitored the presence of birds for over two years and performed cloacal swab analysis for non-pathogenic Escherichia coli, E. coli O157:H7 and Salmonellaenterica, while also monitoring the incidence of other microbial indicators. We also assessed the risks from bird feces by performing observations in a commercial field reported with Salmonella positive samples and by analyzing the survival of foodborne pathogens in bird feces. Our results showed that most of the birds near the crop fields were resident small birds. We did not observe a correlation between the number of birds in sites and the incidence of indicator bacteria (e.g., coliforms, E. coli) in irrigation canal water, with the exception of one out of four sites where water flow was low or stagnant. Using walk-in-traps, 305 birds were captured and placed in short-term captivity to determine the presence of various bacteria. None of the birds tested positive for E. coli O157:H7 or Salmonella. However, nearly 40% of the birds captured were confirmed positive for non-pathogenic E. coli. We found no correlation between age (young, adult, unknown), gender (male, female, unknown) and the incidence of E. coli positive birds, but we observed significantly higher probability of incidence during October-December. The role of relative humidity and temperature on bacterial survival appeared to play a key role in the survival of Salmonella on the leaves of spinach plants in a commercial field. This was also confirmed in laboratory conditions where Salmonella inoculated in bird feces and exposed to 15 °C and 80% RH(Relative humidity) survived beyond 133 days, while at 26 °C and 40% RH, the organism was undetectable after 63 days. Our results suggest that local birds associated with leafy green fields likely pose a minimal impact of risk for food contamination, but also points out the need for increased analysis specifically for E. coli O157:H7. Furthermore, our study suggests the need for expanding research that addresses risks associated with large migratory birds, especially in areas where stagnated water sources would be used for overhead sprinkle irrigation.
  • Enhancing the Noah‐MP Ecosystem Response to Droughts With an Explicit Representation of Plant Water Storage Supplied by Dynamic Root Water Uptake

    Niu, Guo‐Yue; Fang, Yuan‐Hao; Chang, Li‐Ling; Jin, Jiming; Yuan, Hua; Zeng, Xubin; Department of Hydrology and Atmospheric Sciences, The University of Arizona (Blackwell Publishing Ltd, 2020-08-24)
    Plants are able to adapt to changing environments and thus survive droughts. However, most land surface models produce unrealistically low ecosystem resiliency to droughts, degrading the credibility of the model-predicted ecohydrological responses to climate change. We aim to enhance the Noah-MP modeled ecosystem resilience to droughts with an explicit representation of plant water storage supplied by dynamic root water uptake through hydrotropic root growth to meet the transpiration demand. The new model represents plant stomatal water stress factor as a function of the plant water storage and relates the rate of root water uptake to the profile of model-predicted root surface area. Through optimization of major leaf, root, and soil parameters, the new model improves the prediction of leaf area index, ecosystem productivity, evapotranspiration, and terrestrial water storage variations over most basins in the contiguous United States. Sensitivity experiments suggest that both dynamic root water uptake and groundwater capillary rise extend the plants' “memory” of antecedent rainfall. The modeled plants enhance their efficiency to use antecedent rain water stored in shallow soils mainly through more efficient root water uptake over the U.S. Southwest drylands while use that stored in deep soils and aquifers with the aid of groundwater capillary rise in the Central United States. Future plant hydraulic models should not ignore soil water retention model uncertainties and the soil macropore effects on soil water potential and infiltration. ©2020. The Authors.
  • The Photochemical Reflectance Index (PRI) Captures the Ecohydrologic Sensitivity of a Semiarid Mixed Conifer Forest

    Yang, Julia C.; Magney, Troy S.; Yan, Dong; Knowles, John F.; Smith, William K.; Scott, Russell L.; Barron‐Gafford, Greg A.; School of Geography and Development, University of Arizona; School of Natural Resources and the Environment, University of Arizona (Blackwell Publishing Ltd, 2020-10-27)
    At the seasonal time scale, daily photochemical reflectance index (PRI) measurements track changes in photoprotective pigment pools as plants respond to seasonally variable environmental conditions. As such, remotely sensed PRI products present opportunities to study seasonal processes in evergreen conifer forests, where complex vegetation dynamics are difficult to capture due to small annual changes in chlorophyll content or leaf structure. Because PRI is tied explicitly to short- and long-term changes in photoprotective pigments that are responsible for regulating stress, we hypothesize that PRI by extension could serve as a proxy for stomatal response to seasonally changing hydroclimate, assuming plant functional responses to stress covary in space and time. To test this, we characterized PRI in a semiarid, montane mixed conifer forest in the Madrean sky islands of Arizona, USA, during the monsoon growing season subject to precipitation pulse dynamics. To determine the sensitivity of PRI to ecohydrologic variability and associated changes in gross primary productivity (GPP), canopy spectral measurements were coupled with eddy covariance CO2 flux and sap flow measurements. Seasonally, there was a significant relationship between PRI and sap flow velocity (R2 = 0.56), and multiple linear regression analysis demonstrated a PRI response to dynamic water and energy limitations in this system. We conclude that PRI has potential to serve as a proxy for forest functional response to seasonal ecohydrologic forcing. The coordination between photoprotective pigments and seasonal stomatal regulation demonstrated here could aid characterization of vegetation response to future changes in hydroclimate at increasing spatial scales. ©2020. American Geophysical Union. All Rights Reserved.

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