• Provenance of invaders has scale-dependent impacts in a changing wetland ecosystem

      Amatangelo, Kathryn L.; Stevens, Lee; Wilcox, Douglas A.; Jackson, Stephen T.; Sax, Dov F.; Amatangelo, Kathryn L.; Stevens, Lee; Wilcox, Douglas A.; Jackson, Stephen T.; Sax, Dov F.; et al. (PENSOFT PUBL, 2019-11-19)
      Exotic species are associated with a variety of impacts on biodiversity, but it is unclear whether impacts of exotic specks differ from those of native species with similar growth forms or native species invading disturbed sites. We compared presence and abundance of native and exotic invaders with changes in wetland plant species diversity over a 28-year period by re-surveying 22 ponds to identify factors correlated with observed changes. We also compared communities found within dense patches of native and exotic emergent species with similar habits. Within patches, we found no categorical diversity differences between areas dominated by native or exotic emergent species. At the pond scale, the cover of the exotic grass Phragmites australis best predicted change in diversity and evenness over time, likely owing to its significant increase in coverage over the study period. These changes in diversity and evenness were strongest in younger, less successionally-advanced ponds. Changes associated with cover of P. australis in these ponds were not consistent with expected diversity decreases, but instead with a dampening of diversity gains, such that the least-invaded ponds increased in diversity the most over the study period. There were more mixed effects on evenness, ranging from a reduction in evenness gains to actual losses of evenness in the ponds with highest invader cover. In this wetland complex, the habit, origin and invasiveness of species contribute to diversity responses in a scale- and context-dependent fashion. Future efforts to preserve diversity should focus on preventing the arrival and spread of invaders that have the potential to cover large areas at high densities, regardless of their origin. Future studies should also investigate more thoroughly how changes in diversity associated with species invasions are impacted by other ongoing ecosystem changes.
    • Relationship between change in in-vivo exposure distress and PTSD symptoms during exposure therapy for active duty soldiers

      Norr, Aaron M; Bourassa, Kyle J; Stevens, Elizabeth S; Hawrilenko, Matthew J; Michael, Scott T; Reger, Greg M; Univ Arizona (PERGAMON-ELSEVIER SCIENCE LTD, 2019-09)
      Objective: The current study sought to examine the relationship between changes in distress for items on in-vivo exposure hierarchies and posttraumatic stress disorder (PTSD) symptom change over the course of exposure therapy. Methods: Active duty army soldiers (N = 108) were recruited from a military base in the U.S. and were enrolled in a randomized clinical trial comparing Prolonged Exposure (PE), Virtual Reality Exposure (VRE), and a waitlist control for the treatment of PTSD stemming from deployments to Iraq or Afghanistan. PTSD diagnosis followed DSM-IV-TR criteria. Outcome measures were assessed via self-report and clinician interview. The relationships between in-vivo exposure distress, imaginal exposure distress, and PTSD symptoms, were examined in a factor of curves model for participants in the treatment conditions. Results: Analyses revealed that, when controlling for one another, changes in in-vivo exposure distress were significantly associated with changes in PTSD symptoms (beta = 0.75, 95% CI [0.60, 0.90]), while changes in imaginal exposure distress were not (beta = 0.03, 95% CI [-0.27, 0.33]). The model also revealed that after accounting for the shared variation in trajectories of change, symptom clusters did not have unique variation, meaning that symptom clusters did not change independently. Conclusion: Results suggest the possibility that in-vivo exposures are more closely tied to changes in overall PTSD symptoms than imaginal exposures during exposure therapy. Furture research should incorporate more frequent measurement of in-vivo exposure distress to better elucidate these relations over the course of treatment.
    • Do non-human primates really represent others' ignorance? A test of the awareness relations hypothesis

      Horschler, Daniel J; Santos, Laurie R; MacLean, Evan L; Univ Arizona, Cognit Sci Grad Interdisciplinary Program; Univ Arizona, Dept Psychol; Univ Arizona, Cognit Sci Program; Univ Arizona, Sch Anthropol (ELSEVIER SCIENCE BV, 2019-09)
      Non-human primates can often predict how another agent will behave based on that agent's knowledge about the world. But how do non-human primates represent others' knowledge states? Researchers have recently proposed that non-human primates form "awareness relations" to attribute objectively true information to other minds, as opposed to human-like representations that track others' ignorance or false belief states. We present the first explicit test of the awareness relations hypothesis by examining when rhesus macaques' understanding of other agents' knowledge falters. In Experiment 1, monkeys watched an agent observe a piece of fruit (the target object) being hidden in one of two boxes. While the agent's view was occluded, either the fruit moved out of its box and directly back into it, or the box containing the fruit opened and immediately closed. We found that monkeys looked significantly longer when the agent reached incorrectly rather than correctly after the box's movement, but not after the fruit's movement. This result suggests that monkeys did not expect the agent to know the fruit's location when it briefly and arbitrarily moved while the agent could not see it, but did expect the agent to know the fruit's location when only the box moved while the agent could not see it. In Experiment 2, we replicated and extended both findings with a larger sample, a different target object, and opposite directions of motion in the test trials. These findings suggest that monkeys reason about others' knowledge of objects by forming awareness relations which are disrupted by arbitrary spatial manipulation of the target object while an agent has no perceptual access to it.
    • Supplemental Data Files for article "Tracking the growth of the Himalayan fold-and-thrust belt from lower Miocene foreland basin strata: Dumri Formation, western Nepal"

      Stickroth, Simon; Carrapa, Barbara; DeCelles, Peter; Gehrels, George; Thomson, Stuart N.; University of Arizona Department of Geosciences (2019-08-16)
      New data from the lower Miocene Dumri Formation of western Nepal document exhumation of the Himalayan fold-thrust belt and provenance of the Neogene foreland basin system. We employ U-Pb zircon, Th-Pb monazite, 40Ar/39Ar white mica, and zircon fission-track (ZFT) chronometers to detrital minerals to constrain provenance, timing, and rate of exhumation of Himalayan source regions. Clusters of Proterozoic-early Paleozoic (900-400 Ma) Th-Pb monazite and 40Ar/39Ar white mica detrital ages provide evidence for erosion of a Greater Himalayan sequence protolith unaffected by high-grade Eohimalayan metamorphism. A small population of ~40 Ma cooling ages in detrital white mica grains shows exhumation of low-grade metamorphic Tethyan Himalayan sequence through the ~350°C closure temperature along the Tethyan Frontal thrust (proto-South Tibetan detachment) during the late Eocene. Dumri Formation detritus shows a ~12 Myr time difference between cooling of its source rocks through the ~350°C and ~240°C closure temperatures as recorded by ~40-38 Ma youngest peak cooling ages in 40Ar/39Ar detrital white mica and ~28-24 Ma youngest populations in detrital ZFT. Exhumation between ca. 40 Ma and 28 Ma is consistent with slip and exhumation along the Main Central thrust. Combined with similar data from northwestern India, our study suggests west-to-east spatially variable exhumation rates along strike of the Main Central thrust. Our data also show an increase in exhumation during middle Miocene-Pliocene time, which is consistent with growth of the Lesser Himalaya duplex.
    • Transpiration on the rebound in lowland Sumatra

      Roell, A.; Niu, F.; Meijide, A.; Ahongshangbam, J.; Ehbrecht, M.; Guillaume, T.; Gunawan, D.; Hardanto, A.; Hendrayanto; Hertel, D.; et al. (ELSEVIER SCIENCE BV, 2019-08-15)
      Following large-scale conversion of rainforest, rubber and oil palm plantations dominate lowland Sumatra (Indonesia) and other parts of South East Asia today, with potentially far-reaching ecohydrological consequences. We assessed how such land-use change affects plant transpiration by sap flux measurements at 42 sites in selectively logged rainforests, agroforests and rubber and oil palm monoculture plantations in the lowlands of Sumatra. Site-to-site variability in stand-scale transpiration and tree-level water use were explained by stand structure, productivity, soil properties and plantation age. Along a land-use change trajectory forest rubber-oil palm, time-averaged transpiration decreases by 43 +/- 11% from forest to rubber monoculture plantations, but rebounds with conversion to smallholder oil palm plantations. We uncovered that particularly commercial, intensive oil palm cultivation leads to high transpiration (827 +/- 77 mm yr(-1)), substantially surpassing rates at our forest sites (589 +/- 52 mm yr(-1)). Compared to smallholder oil palm, land-use intensification leads to 1.7-times higher transpiration in commercial plantations. Combined with severe soil degradation, the high transpiration may cause periodical water scarcity for humans in oil palm-dominated landscapes. As oil palm is projected to further expand, severe shifts in water cycling after land-cover change and water scarcity due to land-use intensification may become more widespread.
    • Extent and Predictors of Potentially Inappropriate Antidepressant Use Among Older Adults With Dementia and Major Depressive Disorder

      Bhattacharjee, Sandipan; Lee, Jeannie K; Patanwala, Asad E; Vadiei, Nina; Malone, Daniel C; Knapp, Shannon M; Lo-Ciganic, Wei-Hsuan; Burke, William J; Univ Arizona, Coll Pharm, Dept Pharm Practice & Sci; Univ Arizona, Stat Consulting Lab, Bio5 Inst; et al. (ELSEVIER SCIENCE INC, 2019-08-01)
      Objective: To quantify the extent and identify predictors of potentially inappropriate antidepressant use among older adults with dementia and newly diagnosed major depressive disorders (MDD). Methods: This retrospective cohort study included older adults (aged = 65 years) with dementia and newly diagnosed MDD using Medicare 5% sample claims data (2012-2013). Based on Healthcare Effectiveness Data and Information Set guidelines, intake period for new antidepressant medication use was from May 1, 2012, through April 30, 2013. Index prescription start date was the first date of antidepressant prescription claim during the intake period. Dependent variable of this study was potentially inappropriate antidepressant use as defined by the Beers Criteria and the Screening Tool of Older Persons' potentially inappropriate Prescriptions criteria. The authors conducted multiple logistic regression analysis to identify individual-level predictors of potentially inappropriate antidepressant use. Results: The authors' final study sample consisted of 7,625 older adults with dementia and newly diagnosed MDD, among which 7.59% (N = 579) initiated treatment with a potentially inappropriate antidepressant. Paroxetine (N = 394) was the most commonly initiated potentially inappropriate antidepressant followed by amitriptyline (N = 104), nortriptyline (N = 35), and doxepin (N = 32). Initiation of a potentially inappropriate antidepressant was associated with age and baseline use of anxiolytic medications. Conclusion: More than 7% of older adults in the study sample initiated a potentially inappropriate antidepressant, and the authors identified a few individual-level factors significantly associated with it. Appropriately tailored interventions to address modifiable and nonmodifiable factors significantly associated with potentially inappropriate antidepressant prescribing are required to minimize risks in this vulnerable population.
    • Critical care nurses' clinical reasoning about physiologic monitor alarm customisation: An interpretive descriptive study

      Ruppel, Halley; Funk, Marjorie; Whittemore, Robin; Wung, Shu-Fen; Bonafide, Christopher P; Powell Kennedy, Holly; Univ Arizona, Coll Nursing (WILEY, 2019-08-01)
      Aims and objectives To explore clinical reasoning about alarm customisation among nurses in intensive care units. Background Critical care nurses are responsible for detecting and rapidly acting upon changes in patients' clinical condition. Nurses use medical devices including bedside physiologic monitors to assist them in their practice. Customising alarm settings on these devices can help nurses better monitor their patients and reduce the number of clinically irrelevant alarms. As a result, customisation may also help address the problem of alarm fatigue. However, little is known about nurses' clinical reasoning with respect to customising physiologic monitor alarm settings. Design This article is an in-depth report of the qualitative arm of a mixed methods study conducted using an interpretive descriptive methodological approach. Methods Twenty-seven nurses were purposively sampled from three intensive care units in an academic medical centre. Semi-structured interviews were conducted by telephone and were analysed using thematic analysis. Consolidated Criteria for Reporting Qualitative Research (COREQ) reporting guidelines were used. Results Four themes were identified from the interview data: unit alarm culture and context, nurse attributes, motivation to customise and customisation "know-how." A conceptual model demonstrating the relationship of these themes was developed to portray the factors that affect nurses' customisation of alarms. Conclusions In addition to drawing on clinical data, nurses customised physiologic monitor alarms based on their level of clinical expertise and comfort. Nurses were influenced by the alarm culture on their clinical unit and colleagues' and patients' responses to alarms, as well as their own technical understanding of the physiologic monitors. Relevance to clinical practice The results of this study can be used to design strategies to support the application of clinical reasoning to alarm management, which may contribute to more appropriate alarm customisation practices and improvements in safety.
    • Spectral clustering tools applied to Ceres in preparation for OSIRIS-REx color imaging of asteroid (101955) Bennu

      Rizos, Juan Luis; de León, Julia; Licandro, Javier; Campins, Humberto; Popescu, Marcel; Pinilla-Alonso, Noemí; Golish, Dathon; de Prá, Mario; Lauretta, Dante; Univ Arizona, Lunar & Planetary Lab (ACADEMIC PRESS INC ELSEVIER SCIENCE, 2019-08)
      The OSIRIS-REx asteroid sample-return mission is investigating primitive near-Earth asteroid (101955) Bennu. Thousands of images will be acquired by the MapCam instrument onboard the spacecraft, an imager with four color filters based on the Eight-Color Asteroid Survey (ECAS): b' (473 nm), v (550 nm), w (698 nm), and x (847 nm). This set of filters will allow identification and characterization of the absorption band centered at 700 nm and associated with hydrated silicates. In this work, we present and validate a spectral clustering methodology for application to the upcoming MapCam images of the surface of Bennu. Our procedure starts with the projection, calibration, and photometric correction of the images. In a second step, we apply a K-means algorithm and we use the Elbow criterion to identify natural clusters. This methodology allows us to find distinct areas with spectral similarities, which are characterized by parameters such as the spectral slope S' and the center and depth of the 700-nm absorption band, if present. We validate this methodology using images of (1) Ceres from NASA's Dawn mission. In particular, we analyze the Occator crater and Ahuna Mons. We identify one spectral cluster located in the outer parts of the Occator crater interior showing the 700-nm hydration band centered at 698 +/- 7 nm and with a depth of 3.4 +/- 1.0%. We interpret this finding in the context of the crater's near-surface geology.
    • Local niche differences predict genotype associations in sister taxa of desert tortoise

      Inman, Richard; Fotheringham, A. Stewart; Franklin, Janet; Esque, Todd; Edwards, Taylor; Nussear, Kenneth; Univ Arizona, Univ Arizona Genet Core (WILEY, 2019-08)
      Aims: To investigate spatial congruence between ecological niches and genotype in two allopatric species of desert tortoise that are species of conservation concern. Location: Mojave and Sonoran Desert ecoregions; California, Nevada, Arizona, Utah, USA. Methods: We compare ecological niches of Gopherus agassizii and Gopherus morafkai using species distribution modelling (SDM) and then calibrate a pooled-taxa distribution model to explore local differences in species-environment relationships based on the spatial residuals of the pooled-taxa model. We use multiscale geographically weighted regression (MGWR) applied to those residuals to estimate local species-environment relationships that can vary across the landscape. We identify multivariate clusters in these local species-environment relationships and compare them against models of (a) a geographically based taxonomic designation for two sister species and (b) an environmental ecoregion designation, with respect to their ability to predict a genotype association index for these two species. Results: We find non-identical niches for these species, with differences that span physiographic and vegetation niche dimensions. We find evidence for two distinct clusters of local species-environment relationships that when mapped, predict an index of genotype association for the two sister taxa better than did either the geographically based taxonomic designation or an environmental ecoregion designation. Main conclusions: Exploring local species-environment relationships by coupling SDM and MGWR can benefit studies of biogeography and conservation. We find that niche separation in habitat selection conforms to genotypic differences between sister taxa of tortoise in a recent secondary contact zone. This result may inform decision making by agencies with regulatory or land management authority for the two sister taxa addressed here.
    • A metacognitive intervention for teaching fractions to students with or at-risk for learning disabilities in mathematics

      Hacker, Douglas J.; Kiuhara, Sharlene A.; Levin, Joel R.; Univ Arizona, Educ Psychol (SPRINGER HEIDELBERG, 2019-08)
      Assessment data from the United States and international reports of student achievement indicate that upper elementary students are failing to meet basic levels of proficiency in fractions and writing, and that this is particularly prevalent with students with or at-risk for learning disabilities in mathematics. Proficiency with fractions has been identified as foundational for learning higher-level mathematics but remains one of the most difficult skills for students to learn. In addition, students' difficulty with fractions is exacerbated because of increased chances of comorbidity with language learning problems, particularly difficulties constructing arguments and communicating using writing. We describe FACT+(RC2)-C-2, a language-based, metacognitive instructional intervention that was designed using the Self-Regulated Strategy Development model (SRSD) for teaching foundational concepts of fractions. The results from two studies in which the intervention was administered to upper elementary students who exhibit mathematics difficulties indicated selected increases in students' computational accuracy, quality of mathematical reasoning, number of rhetorical elements, and total words. With evidence of improved performance in these areas, FACT+(RC2)-C-2 holds promise for helping these students become proficient self-regulated learners.
    • Disparities in colon and rectal cancer queried individually between Hispanics and Whites

      Koblinski, Jenna; Jandova, Jana; Pandit, Viraj; Omesiete, Pamela; Nfonsam, Valentine; Univ Arizona, Dept Surg (PIONEER BIOSCIENCE PUBL CO, 2019-08)
      Background: Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the second leading cause of cancer related deaths in the United States. Racial disparities between Hispanics and Whites exist for incidence of late-onset (LO) CRC. However, not much is known about potential disparities between colon cancer (CC) and rectal cancer (RC) incidence queried individually. Methods: Using the SEER database data from 2000 to 2010, we obtained the national estimates of CC and RC for Hispanics and Whites. We analyzed trends in incidence, mortality, gender and stage of disease for early-onset (EO) (<50 years old) and LO (>50 years old) CC and RC. Results: In Hispanics, the overall incidence of CC and RC increased by 47% and 52%, respectively; while in Whites, the overall incidence of CC and RC decreased by 13% and 2% respectively. Incidence of EO CC increased in both Hispanics and Whites by 83% and 17%, respectively, and incidence of EO RC also increased for both groups with a 76% increase in Hispanics and a 34% increase in Whites. For LO CC, the incidence increased by 37% in Hispanics while it decreased by 17% in Whites and for LO RC, the trend in incidence increased in Hispanics by 41%, but decreased in Whites by 11%. Conclusions: This study established that the incidence of CC and RC are different and there is racial disparity in incidence between Whites and Hispanics. This study, hopefully, will help in crafting public policy that might help in addressing this disparity.
    • Dark halos produced by current impact cratering on Mars

      Bart, Gwendolyn D.; Daubar, Ingrid J.; Ivanov, Boris A.; Dundas, Colin M.; McEwen, Alfred S.; Univ Arizona, Dept Planetary Sci (ACADEMIC PRESS INC ELSEVIER SCIENCE, 2019-08)
      Hundreds of new impact craters have been observed to form on Mars since spacecraft began imaging that planet. New impact craters produced visible ejecta deposits and many of them also have visible rays, similar to lunar and mercurian craters. However, some of the new martian impact craters have a circular feature of relatively low reflectance that we call a "halo." This feature is distinct from the usual visible ejecta deposits or ray patterns. In this paper we present an observational study of this halo feature and we discuss the results of this study with respect to the nature of the halos: what they are and how they may have formed. To address these questions, we measured diameters of both halos and their central craters. We found a strong correlation between halo diameter and crater diameter, which indicates that the nature of the halos is fundamentally governed by the amount of impact energy available at their formation. Specifically, halo size is controlled by impact energy according to the non-linear relationship D-H proportional to E-2/3, where D-H is the diameter of the halo and E is the impact energy. We also found that certain factors may influence the formation of the halos: a thicker dust layer and lower elevations are both correlated with larger halos. From these correlations we conclude that the local surface characteristics as well as local atmospheric pressure influence the formation of the halos. Our description and analysis of the martian halo features provide a framework upon which specific halo formation mechanisms can be developed and tested in the future.
    • A Regime-Based Evaluation of Southern and Northern Great Plains Warm-Season Precipitation Events in WRF

      Wang, Jingyu; Dong, Xiquan; Kennedy, Aaron; Hagenhoff, Brooke; Xi, Baike; Univ Arizona, Dept Hydrol & Atmospher Sci (AMER METEOROLOGICAL SOC, 2019-08)
      A competitive neural network known as the self-organizing map (SOM) is used to objectively identify synoptic patterns in the North American Regional Reanalysis (NARR) for warm-season (April-September) precipitation events over the Southern and Northern Great Plains (SGP/NGP) from 2007 to 2014. Classifications for both regions demonstrate contrast in dominant synoptic patterns ranging from extratropical cyclones to subtropical ridges, all of which have preferred months of occurrence. Precipitation from deterministic Weather Research and Forecasting (WRF) Model simulations run by the National Severe Storms Laboratory (NSSL) are evaluated against National Centers for Environmental Prediction (NCEP) Stage IV observations. The SGP features larger observed precipitation amount, intensity, and coverage, as well as better model performance than the NGP. Both regions' simulated convective rain intensity and coverage have good agreement with observations, whereas the stratiform rain (SR) is more problematic with weaker intensity and larger coverage. Further evaluation based on SOM regimes shows that WRF bias varies with the type of meteorological forcing, which can be traced to differences in the diurnal cycle and properties of stratiform and convective rain. The higher performance scores are generally associated with the extratropical cyclone condition than the subtropical ridge. Of the six SOM classes over both regions, the largest precipitation oversimulation is found for SR dominated classes, whereas a nocturnal negative precipitation bias exists for classes featuring upscale growth of convection.
    • Pricing Intertemporal Risk When Investment Opportunities Are Unobservable

      Cederburg, Scott; Univ Arizona, Eller Coll Management (CAMBRIDGE UNIV PRESS, 2019-08)
      The intertemporal capital asset pricing model (ICAPM) predicts that an unobservable factor capturing changes in expected market returns should be priced in the cross section. My Bayesian framework accounts for uncertainty in the intertemporal risk factor and gauges the effects of prior information about investment opportunities on model inferences. Whereas an uninformative prior specification produces weak evidence that intertemporal risk is priced, incorporating prior information about market-return predictability generates a large space of ex ante reasonable priors in which the estimated intertemporal risk factor is positively priced. Overall, the cross-sectional tests reject the capital asset pricing model (CAPM) and indicate support for the ICAPM.
    • Examining social capital in relation to sleep duration, insomnia, and daytime sleepiness

      Robbins, Rebecca; Jean-Louis, Girardin; Gallagher, Rebecca A; Hale, Lauren; Branas, Charles C; Gooneratne, Nalaka; Alfonso-Miller, Pamela; Perlis, Michael; Grandner, Michael A; Univ Arizona, Dept Psychiat, Sleep & Hlth Res Program, Coll Med (ELSEVIER SCIENCE BV, 2019-08)
      Objective: Sleep, which plays an important role in health and well-being, is socially patterned such that certain demographic groups have worse sleep health than others. One possible mechanism driving sleep disparities is social capital. The current study examines the association between social capital and self-reported sleep variables (eg, duration, insomnia symptoms, and daytime sleepiness) among a sample of 1007 participants from the Sleep Health and Activity, Diet and Environment Study (SHADES). Methods: Logistic regressions were used to estimate whether the sleep variables were associated with social capital measures. All models control for age, sex, race/ethnicity (Non-Hispanic White, Black/African-American, Hispanic/Latino, Asian, and multicultural/other), income, and education (less than high school, high school graduate, some college, and college graduate). Results: Lower likelihood of membership in groups was seen for long sleepers (>9hrs, p-value<0.05) and beliefs that neighbors rarely/never help each other was more likely among short sleepers (5-6hrs, p-value<0.05), relative to 7-8 h sleepers. A decreased sense of belonging was seen among short sleepers (5-6hrs, p-value<0.05). Decreased likelihood of trust was reported by those with moderate-severe insomnia (p-value<0.05). Similarly, neighborhood improvement efforts were less likely among individuals with moderate-to-severe insomnia (p-value<0.05). Conclusions: Results of our study show that short and long sleep duration, as well as insomnia, were inversely related to measures of social capital, such as group memberships and a sense of neighborhood belonging. Future research may explore the directionality of the relationship between social capital and sleep and perhaps consider future interventions to improve low social capital and/or poor sleep in community samples.
    • Prokaryotic Community Structure and Metabolisms in Shallow Subsurface of Atacama Desert Playas and Alluvial Fans After Heavy Rains: Repairing and Preparing for Next Dry Period

      Fernández-Martínez, Miguel Ángel; dos Santos Severino, Rita; Moreno-Paz, Mercedes; Gallardo-Carreño, Ignacio; Blanco, Yolanda; Warren-Rhodes, Kimberley; García-Villadangos, Miriam; Ruiz-Bermejo, Marta; Barberán, Albert; Wettergreen, David; et al. (Frontiers Media SA, 2019-07-24)
      The Atacama Desert, the oldest and driest desert on Earth, displays significant rains only once per decade. To investigate how microbial communities take advantage of these sporadic wet events, we carried out a geomicrobiological study a few days after a heavy rain event in 2015. Different physicochemical and microbial community analyses were conducted on samples collected from playas and an alluvial fan from surface, 10, 20, 50, and 80 cm depth. Gravimetric moisture content peaks were measured in 10 and 20 cm depth samples (from 1.65 to 4.1% w/w maximum values) while, in general, main anions such as chloride, nitrate, and sulfate concentrations increased with depth, with maximum values of 13-1,125; 168-10,109; and 9,904-30,952 ppm, respectively. Small organic anions such as formate and acetate had maximum concentrations from 2.61 to 3.44 ppm and 6.73 to 28.75 ppm, respectively. Microbial diversity inferred from DNA analysis showed Actinobacteria and Alphaproteobacteria as the most abundant and widespread bacterial taxa among the samples, followed by Chloroflexi and Firmicutes at specific sites. Archaea were mainly dominated by Nitrososphaerales, Methanobacteria, with the detection of other groups such as Halobacteria. Metaproteomics showed a high and even distribution of proteins involved in primary metabolic processes such as energy production and biosynthetic pathways, and a limited but remarkable presence of proteins related to resistance to environmental stressors such as radiation, oxidation, or desiccation. The results indicated that extra humidity in the system allows the microbial community to repair, and prepare for the upcoming hyperarid period. Additionally, it supplies biomarkers to the medium whose preservation potential could be high under strong desiccation conditions and relevant for planetary exploration.
    • A Novel, Highly Related Jumbo Family of Bacteriophages That Were Isolated Against Erwinia

      Sharma, Ruchira; Pielstick, Brittany A.; Bell, Kimberly A.; Nieman, Tanner B.; Stubbs, Olivia A.; Yeates, Edward L.; Baltrus, David A.; Grose, Julianne H.; Univ Arizona, Sch Plant Sci (Frontiers Media SA, 2019-07-23)
      Erwinia amylovora is a plant pathogen from the Erwiniaceae family and a causative agent of the devastating agricultural disease fire blight. Here we characterize eight lytic bacteriophages of E. amylovora that we isolated from the Wasatch front (Utah, United States) that are highly similar to vB_EamM_Ea35-70 which was isolated in Ontario, Canada. With the genome size ranging from 271 to 275 kb, this is a novel jumbo family of bacteriophages. These jumbo bacteriophages were further characterized through genomic and proteomic comparison, mass spectrometry, host range and burst size. Their proteomes are highly unstudied, with over 200 putative proteins with no known homologs. The production of 27 of these putative proteins was confirmed by mass spectrometry analysis. These bacteriophages appear to be most similar to bacteriophages that infect Pseudomonas and Ralstonia rather than Enterobacteriales bacteria by protein similarity, however, we were only able to detect infection of Erwinia and the closely related strains of Pantoea.
    • H-band discovery of additional second-generation stars in the Galactic bulge globular cluster NGC 6522 as observed by APOGEE and Gaia

      Cunha, K.; Univ Arizona, Steward Observ (EDP Sciences, 2019-07-22)
      We present an elemental abundance analysis of high-resolution spectra for five giant stars spatially located within the innermost regions of the bulge globular cluster NGC 6522 and derive Fe, Mg, Al, C, N, O, Si, and Ce abundances based on H-band spectra taken with the multi-object APOGEE-north spectrograph from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. Of the five cluster candidates, two previously unremarked stars are confirmed to have second-generation (SG) abundance patterns, with the basic pattern of depletion in C and Mg simultaneous with enrichment in N and Al as seen in other SG globular cluster populations at similar metallicity. In agreement with the most recent optical studies, the NGC 6522 stars analyzed exhibit (when available) only mild overabundances of the s-process element Ce, contradicting the idea that NGC 6522 stars are formed from gas enriched by spinstars and indicating that other stellar sources such as massive AGB stars could be the primary polluters of intra-cluster medium. The peculiar abundance signatures of SG stars have been observed in our data, confirming the presence of multiple generations of stars in NGC 6522.
    • On the Effect of Environment on Line Emission from the Circumgalactic Medium

      Zhang, Huanian; Zaritsky, Dennis; Behroozi, Peter; Werk, Jessica; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2019-07-22)
      We measure differences in the emission-line flux from the circumgalactic medium (CGM) of galaxies in different environments. Such differences could be a critical clue in explaining a range of galaxy properties that depend on environment. Using large samples of stacked archival spectra from the Sloan Digital Sky Survey, we find that the H alpha + [N II] emission-line flux from the CGM within 50 kpc of similar to L* galaxies is lower both for galaxies that lie within a projected distance of similar to 500 kpc from a massive (M-* > 10(11) M-circle dot) galaxy and for galaxies in richer/denser environments. The environmental differences are statistically significant even after we control for galaxy mass and morphology. We interpret these observations as a direct signature of environmentally caused strangulation. We present a simple, heuristic model for the effect of a massive parent galaxy. In this model, the CGM cool gas fraction within 50 kpc is significantly decreased for galaxies that lie within 700 kpc of a massive galaxy, with about 80% of the cool gas removed even when the galaxy is at a distance of 500 kpc from its massive parent. However, we discuss alternative physical causes for the observed behavior and discuss ways forward in addressing open questions.
    • ASASSN-15pz: Revealing Significant Photometric Diversity among 2009dc-like, Peculiar SNe Ia

      Chen, Ping; Dong, Subo; Katz, Boaz; Kochanek, C. S.; Kollmeier, Juna A.; Maguire, K.; Phillips, M. M.; Prieto, J. L.; Shappee, B. J.; Stritzinger, M. D.; et al. (IOP PUBLISHING LTD, 2019-07-22)
      We report comprehensive multi-wavelength observations of a peculiar Type Ia-like supernova ("SN Ia-pec") ASASSN-15pz. ASASSN-15pz is a spectroscopic "twin" of SN 2009dc, a so-called "Super-Chandrasekhar-mass" SN, throughout its evolution, but it has a peak luminosity M-B,(peak) = -19.69 +/- 0.12 mag that is approximate to 0.6 mag dimmer and comparable to the SN 1991T sub-class of SNe Ia at the luminous end of the normal width-luminosity relation. The synthesized Ni-56 mass of M-56Ni = 1.13 +/- 0.14 M-circle dot is also substantially less than that found for several 2009dc-like SNe. Previous well-studied 2009dc-like SNe have generally suffered from large and uncertain amounts of host-galaxy extinction, which is negligible for ASASSN-15pz. Based on the color of ASASSN-15pz, we estimate a host extinction for SN 2009dc of E(B - V)(host) = 0.12 mag and confirm its high luminosity (M-B,(peak) [2009dc] approximate to -20.3 mag). The 2009dc-like SN population, which represents similar to 1% of SNe Ia, exhibits a range of peak luminosities, and do not fit onto the tight width-luminosity relation. Their optical light curves also show significant diversity of late-time (greater than or similar to 50 days) decline rates. The nebular-phase spectra provide powerful diagnostics to identify the 2009dc-like events as a distinct class of SNe Ia. We suggest referring to these sources using the phenomenology-based "2009dc-like SN Ia-pec" instead of "Super-Chandrasekhar SN Ia," which is based on an uncertain theoretical interpretation.