• Vacuum stabilized by anomalous magnetic moment

      Evans, Stefan; Rafelski, Johann; Univ Arizona, Dept Phys (AMER PHYSICAL SOC, 2018-07-10)
      An analytical result for Euler-Heisenberg effective action, valid for electron spin g-factor vertical bar g vertical bar < 2, was extended to the domain vertical bar g vertical bar > 2 via discovered periodicity of the effective action. This allows for a simplified computation of vacuum instability modified by the electron's measured g = 2.002319. We find a strong suppression of vacuum decay into electron positron pairs when magnetic fields are dominant. The result is reminiscent of mass catalysis by magnetic fields.
    • VALES – IV. Exploring the transition of star formation efficiencies between normal and starburst galaxies using APEX/SEPIA Band-5 and ALMA at low redshift

      Cheng, C; Ibar, E; Hughes, T M; Villanueva, V; Leiton, R; Orellana, G; Muñoz Arancibia, A; Lu, N; Xu, C K; Willmer, C N A; et al. (OXFORD UNIV PRESS, 2018-03-21)
      In this work, we present new the Swedish-ESO PI receiver for the Atacama Pathfinder Experiment APEX/SEPIA Band-5 observations targeting the CO (J = 2-1) emission line of 24 Herschel-detected galaxies at z = 0.1-0.2. Combining this sample with our recent new Valparafso ALMA Line Emission Survey (VALES), we investigate the star formation efficiencies [SFEs = star formation rate (SFR)/M-H2] of galaxies at low redshift. We find the SFE of our sample bridges the gap between normal star-forming galaxies and Ultra-Luminous Infrared Galaxies (ULIRGs), which are thought to be triggered by different star formation modes. Considering the SFE' as the SFR and the L'(CO) ratio, our data show a continuous and smooth increment as a function of infrared luminosity (or star formation rate) with a scatter about 0.5 dex, instead of a steep jump with a bimodal behaviour. This result is due to the use of a sample with a much larger range of sSFR/sSFR(ms) using LIRGs, with luminosities covering the range between normal and ULIRGs. We conclude that the main parameters controlling the scatter of the SFE in star-forming galaxies are the systematic uncertainty of the alpha(CO) conversion factor, the gas fraction, and physical size.
    • Validating Resilience and Vulnerability Indices in the Context of Natural Disasters

      Bakkensen, Laura A.; Fox-Lent, Cate; Read, Laura K.; Linkov, Igor; University of Arizona, School of Government and Public Policy; University of Arizona; School of Government and Public Policy; Tucson AZ USA; U.S. Army Corps of Engineers; Engineer Research & Development Center; Concord MA USA; U.S. Army Corps of Engineers; Engineer Research & Development Center; Concord MA USA; U.S. Army Corps of Engineers; Engineer Research & Development Center; Concord MA USA (WILEY, 2017-05)
      Due to persistent and serious threats from natural disasters around the globe, many have turned to resilience and vulnerability research to guide disaster preparation, recovery, and adaptation decisions. In response, scholars and practitioners have put forth a variety of disaster indices, based on quantifiable metrics, to gauge levels of resilience and vulnerability. However, few indices are empirically validated using observed disaster impacts and, as a result, it is often unclear which index should be preferred for each decision at hand. Thus, we compare and empirically validate five of the top U.S. disaster indices, including three resilience indices and two vulnerability indices. We use observed disaster losses, fatalities, and disaster declarations from the southeastern United States to empirically validate each index. We find that disaster indices, though thoughtfully substantiated by literature and theoretically persuasive, are not all created equal. While four of the five indices perform as predicted in explaining damages, only three explain fatalities and only two explain disaster declarations as expected by theory. These results highlight the need for disaster indices to clearly state index objectives and structure underlying metrics to support validation of the results based on these goals. Further, policymakers should use index results carefully when developing regional policy or investing in resilience and vulnerability improvement projects.
    • Validation of a Stochastic Discrete Event Model Predicting Virus Concentration on Nurse Hands

      Wilson, Amanda M; Reynolds, Kelly A; Verhougstraete, Marc P; Canales, Robert A; Univ Arizona, Dept Community Environm & Policy, Mel & Enid Zuckerman Coll Publ Hlth (WILEY, 2019-08-01)
      Understanding healthcare viral disease transmission and the effect of infection control interventions will inform current and future infection control protocols. In this study, a model was developed to predict virus concentration on nurses' hands using data from a bacteriophage tracer study conducted in Tucson, Arizona, in an urgent care facility. Surfaces were swabbed 2 hours, 3.5 hours, and 6 hours postseeding to measure virus spread over time. To estimate the full viral load that would have been present on hands without sampling, virus concentrations were summed across time points for 3.5- and 6-hour measurements. A stochastic discrete event model was developed to predict virus concentrations on nurses' hands, given a distribution of virus concentrations on surfaces and expected frequencies of hand-to-surface and orifice contacts and handwashing. Box plots and statistical hypothesis testing were used to compare the model-predicted and experimentally measured virus concentrations on nurses' hands. The model was validated with the experimental bacteriophage tracer data because the distribution for model-predicted virus concentrations on hands captured all observed value ranges, and interquartile ranges for model and experimental values overlapped for all comparison time points. Wilcoxon rank sum tests showed no significant differences in distributions of model-predicted and experimentally measured virus concentrations on hands. However, limitations in the tracer study indicate that more data are needed to instill more confidence in this validation. Next model development steps include addressing viral concentrations that would be found naturally in healthcare environments and measuring the risk reductions predicted for various infection control interventions.
    • Validation of salivary oxytocin and vasopressin as biomarkers in domestic dogs

      MacLean, Evan L.; Gesquiere, Laurence R.; Gee, Nancy; Levy, Kerinne; Martin, W. Lance; Carter, C. Sue; Univ Arizona, Sch Anthropol (ELSEVIER SCIENCE BV, 2018-01)
      Background: Oxytocin (OT) and Vasopressin (AVP) are phylogenetically conserved neuropeptides with effects on social behavior, cognition and stress responses. Although OT and AVP are-most commonly measured in blood, urine and cerebrospinal fluid (CSF), these approaches present an array of challenges including concerns related to the invasiveness of sample collection, the potential for matrix interference in immunoassays, and whether samples can be collected at precise time points to assess event-linked endocrine responses. New method: We validated enzyme-linked immunosorbent assays (ELISAs) for the measurement of salivary OT and AVP in domestic dogs. Results: Both OT and AVP were present in dog saliva and detectable by ELISA and high performance liquid chromatography - mass spectrometry (HPLC-MS). OT concentrations in dog saliva were much higher than those typically detected in humans. OT concentrations in the same samples analyzed with and without sample extraction were highly correlated, but this was not true for AVP. ELISA validation studies revealed good accuracy and parallelism, both with and without solid phase extraction. Collection of salivary samples with different synthetic swabs, or following salivary stimulation or the consumption of food led to variance in results. However, samples collected from the same dogs using different techniques tended to be positively correlated. We detected concurrent elevations in salivary and plasma OT during nursing. Comparison with existing methods: There are currently no other validated methods for measuring OT/AVP in dog saliva. Conclusions: OT and AVP are present in dog saliva, and ELISAs for their detection are methodologically valid. (C) 2017 Elsevier B.V. All rights reserved.
    • Validation of Spaceborne and Modelled Surface Soil Moisture Products with Cosmic-Ray Neutron Probes

      Montzka, Carsten; Bogena, Heye; Zreda, Marek; Monerris, Alessandra; Morrison, Ross; Muddu, Sekhar; Vereecken, Harry; Univ Arizona, Dept Hydrol & Atmospher Sci (MDPI AG, 2017-01-25)
      ]The scale difference between point in situ soil moisture measurements and low resolution satellite products limits the quality of any validation efforts in heterogeneous regions. Cosmic Ray Neutron Probes (CRNP) could be an option to fill the scale gap between both systems, as they provide area-average soil moisture within a 150-250 m radius footprint. In this study, we evaluate differences and similarities between CRNP observations, and surface soil moisture products from the Advanced Microwave Scanning Radiometer 2 (AMSR2), the METOP-A/B Advanced Scatterometer (ASCAT), the Soil Moisture Active and Passive (SMAP), the Soil Moisture and Ocean Salinity (SMOS), as well as simulations from the Global Land Data Assimilation System Version 2 (GLDAS2). Six CRNPs located on five continents have been selected as test sites: the Rur catchment in Germany, the COSMOS sites in Arizona and California (USA), and Kenya, one CosmOz site in New SouthWales (Australia), and a site in Karnataka (India). Standard validation scores as well as the Triple Collocation (TC) method identified SMAP to provide a high accuracy soil moisture product with low noise or uncertainties as compared to CRNPs. The potential of CRNPs for satellite soil moisture validation has been proven; however, biomass correction methods should be implemented to improve its application in regions with large vegetation dynamics.
    • Validation of the Predicted Heat Strain Model in Hot Underground Mines

      Lazaro, Paloma; Momayez, Moe; Univ Arizona, Dept Min & Geol Engn (SPRINGER HEIDELBERG, 2019-06-27)
      Heat-related illnesses (HRI) are relatively common in both hot surface and underground mining operations. When workers are exposed to extreme heat or strenuous work in a hot environment, they become prone to heat stress. Heat strain is the result of the body's response to external and internal heat stress. It is therefore vital for the conditions leading to heat strain be detected and treated in a timely manner. Heat-related illnesses are manifested by exhaustion and heat stroke. The predicted heat strain (PHS) [ISO 7933 (2004)] model has been developed to predict the health condition of the worker in terms of core body temperature and water loss. The PHS model tested in this study is based on eight physical parameters that are measured at different intervals during a work shift. They include air temperature, humidity, radiation, air velocity, metabolic rate, clothing insulation, posture, and acclimatization. The model predictions are then compared with a direct physiological measurement, such as core body temperature. We present the results of an extensive study that monitored and predicted body's response to heat stress under different environmental and working conditions. The PHS model provided reliable results in most instances in comparison with other prediction methods currently in use in the field.
    • Validity and Reliability of a New Measure of Nursing Experience With Unintended Consequences of Electronic Health Records.

      Gephart, Sheila M; Bristol, Alycia A; Dye, Judy L; Finley, Brooke A; Carrington, Jane M; Univ Arizona, Coll Nursing (LIPPINCOTT WILLIAMS & WILKINS, 2016-10)
      Unintended consequences of electronic health records represent undesired effects on individuals or systems, which may contradict initial goals and impact patient care. The purpose of this study was to determine the extent to which a new quantitative measure called the Carrington-Gephart Unintended Consequences of Electronic Health Record Questionnaire (CG-UCE-Q) was valid and reliable. Then, it was used to describe acute care nurses' experience with unintended consequences of electronic health records and relate them to the professional practice environment. Acceptable content validity was achieved for two rounds of surveys with nursing informatics experts (n = 5). Then, acute care nurses (n = 144) were recruited locally and nationally to complete the survey and describe the frequency with which they encounter unintended consequences in daily work. Principal component analysis with oblique rotation was applied to evaluate construct validity. Correlational analysis with measures of the professional practice environment and workarounds was used to evaluate convergent validity. Test-retest reliability was measured in the local sample (N = 68). Explanation for 63% of the variance across six subscales (patient safety, system design, workload issues, workarounds, technology barriers, and sociotechnical impact) supported construct validity. Relationships were significant between subscales for electronic health record-related threats to patient safety and low autonomy/leadership (P < .01), poor communication about patients (P < .01), and low control over practice (P < .01). The most frequent sources of unintended consequences were increased workload, interruptions that shifted tasks from the computer, altered workflow, and the need to duplicate data entry. Convergent validity of the CG-UCE-Q was moderately supported with both the context and processes of workarounds with strong relationships identified for when nurses perceived a block and altered process to work around it to subscales in the CG-UCE-Q for electronic health record system design (P < .01) and technological barriers (P < .01).
    • Validity and reliability of four language mapping paradigms

      Wilson, Stephen M.; Bautista, Alexa; Yen, Melodie; Lauderdale, Stefanie; Eriksson, Dana K.; Univ Arizona, Dept Speech Language & Hearing Sci; Univ Arizona, Dept Neurol; Univ Arizona, Dept Linguist (ELSEVIER SCI LTD, 2017)
      Language areas of the brain can be mapped in individual participants with functional MRI. We investigated the validity and reliability of four language mapping paradigms that may be appropriate for individuals with acquired aphasia: sentence completion, picture naming, naturalistic comprehension, and narrative comprehension. Five neurologically normal older adults were scanned on each of the four paradigms on four separate occasions. Validity was assessed in terms of whether activation patterns reflected the known typical organization of language regions, that is, lateralization to the left hemisphere, and involvement of the left inferior frontal gyrus and the left middle and/or superior temporal gyri. Reliability (test-retest reproducibility) was quantified in terms of the Dice coefficient of similarity, which measures overlap of activations across time points. We explored the impact of different absolute and relative voxelwise thresholds, a range of cluster size cutoffs, and limitation of analyses to a priori potential language regions. We found that the narrative comprehension and sentence completion paradigms offered the best balance of validity and reliability. However, even with optimal combinations of analysis parameters, there were many scans on which known features of typical language organization were not demonstrated, and test-retest reproducibility was only moderate for realistic parameter choices. These limitations in terms of validity and reliability may constitute significant limitations for many clinical or research applications that depend on identifying language regions in individual participants. (C) 2016 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license
    • The Validity of 21 cm Spin Temperature as a Kinetic Temperature Indicator in Atomic and Molecular Gas

      Shaw, Gargi; Ferland, G. J.; Hubeny, I.; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2017-07-14)
      The gas kinetic temperature (T-K) of various interstellar environments is often inferred from observations that can deduce level populations of atoms, ions, or molecules using spectral line observations; H I 21 cm is perhaps the most widely used, and has a long history. Usually the H I 21 cm line is assumed to be in thermal equilibrium. and the populations are given by the Boltzmann distribution. A variety of processes, many involving Ly alpha, can affect the 21 cm line. Here we show how this is treated in the spectral simulation code Cloudy, and present numerical simulations of environments where this temperature indicator is used, with a detailed treatment of the physical processes that determine level populations within H-0. We discuss situations where this temperature indicator traces TK, cases where it fails, as well as the effects of Lya pumping on the 21 cm spin temperature. We also show that the Lya excitation temperature rarely traces the gas kinetic temperature.
    • Validity of two retrospective questionnaire versions of the Consensus Sleep Diary: the whole week and split week Self-Assessment of Sleep Surveys

      Dietch, Jessica R; Sethi, Kevin; Slavish, Danica C; Taylor, Daniel J; Univ Arizona, Dept Psychol (ELSEVIER, 2019-11-01)
      Objective/Background: Prospective, daily sleep diaries are the gold standard for assessing subjective sleep but are not always feasible for cross-sectional or epidemiological studies. The current study examined psychometric properties of two retrospective questionnaire versions of the Consensus Sleep Diary. Participants/Methods: College students (N = 131, mean age = 19.39 +/- 1.65; 73% female) completed seven days of prospective sleep diaries then were randomly assigned to complete either the Self-Assessment of Sleep Survey (SASS), which assessed past week sleep (n = 70), or the SASS-Split (SASS-Y), which assessed weekday/weekend sleep separately (n = 61). Participants also completed psychosocial/sleep questionnaires including the Pittsburgh Sleep Quality Index (PSQI). Sleep parameters derived from SASS, SASS-Y, PSQI, and sleep diaries were assessed via Bland Altman plots, limits of agreement, mean differences, and correlations. Results: SASS-Y demonstrated stronger correlations with prospective sleep diaries and slightly less biased estimates (r = 0.51 to 0.85, alpha = -0.43 to 1.70) compared to SASS (r = 0.29 to 0.84, alpha = -1.63 to 2.33) for terminal wakefulness (TWAK), sleep onset latency (SOL), sleep efficiency (SE), and quality (QUAL). SASS resulted in slightly less bias for total sleep time (TST) and wake after sleep onset (WASO) (alpha = -0.65 and 0.93, respectively) compared to SASS-Y (alpha = 14.90 and 1.05, respectively). SASS and SASS-Y demonstrated greater convergence with sleep diary than PSQI. Conclusions: Results demonstrated good psychometric properties for the SASS and SASS-Y. When prospective sleep diaries are not feasible, the SASS and SASS-Y are acceptable substitutes to retrospectively estimate sleep parameters. Retrospective estimation of sleep parameters separately for weekdays/weekends may offer advantages compared to whole week estimation. (C) 2019 Published by Elsevier B.V.
    • The value of art-oriented pedagogical approaches to the teaching of optics and photonics

      Pompea, Stephen M.; Regens, Nancy L.; Univ Arizona (SPIE-INT SOC OPTICAL ENGINEERING, 2017-08-16)
      Art-oriented pedagogical approaches have been successfully applied to optics and photonics education. We will describe how art-based programs that incorporate a Visual Thinking Strategies (VTS) approach can be used by optics and photonics educators. VTS encourages both a deep appreciation of the content of optics images and phenomena and a highly participatory approach to understanding them. This type of approach has been used by the authors in a variety of educational settings including teacher professional development workshops, museum and science center-based programs, after school programs and in two-week intensive summer academies for students. These approaches work well with multiple age groups including primary and secondary grade students, university students, and adults who may have little apparent connection to optics and photonics. This art-science hybrid approach can be used by university professors, optics/ photonics professionals who do public programs, museum educators, and classroom science teachers.
    • The value of blood cytokines and chemokines in assessing COPD

      Bradford, Eric; Jacobson, Sean; Varasteh, Jason; Comellas, Alejandro P.; Woodruff, Prescott; O’Neal, Wanda; DeMeo, Dawn L.; Li, Xingnan; Kim, Victor; Cho, Michael; et al. (BIOMED CENTRAL LTD, 2017-10-24)
      Background: Blood biomarkers are increasingly used to stratify high risk chronic obstructive pulmonary disease (COPD) patients; however, there are fewer studies that have investigated multiple biomarkers and replicated in multiple large well-characterized cohorts of susceptible current and former smokers. Methods: We used two MSD multiplex panels to measure 9 cytokines and chemokines in 2123 subjects from COPDGene and 1117 subjects from SPIROMICS. These biomarkers included: interleukin (IL)-2, IL-6, IL-8, IL-10, tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, eotaxin/CCL-11, eotaxin-3/CCL-26, and thymus and activation-regulated chemokine (TARC)/CCL-17. Regression models adjusted for clinical covariates were used to determine which biomarkers were associated with the following COPD phenotypes: airflow obstruction (forced expiratory flow at 1 s (FEV1%) and FEV1/forced vital capacity (FEV1/FVC), chronic bronchitis, COPD exacerbations, and emphysema. Biomarker-genotype associations were assessed by genome-wide association of single nucleotide polymorphisms (SNPs). Results: Eotaxin and IL-6 were strongly associated with airflow obstruction and accounted for 3-5% of the measurement variance on top of clinical variables. IL-6 was associated with progressive airflow obstruction over 5 years and both IL-6 and IL-8 were associated with progressive emphysema over 5 years. None of the biomarkers were consistently associated with chronic bronchitis or COPD exacerbations. We identified one novel SNP (rs9302690 SNP) that was associated with CCL17 plasma measurements. Conclusion: When assessing smoking related pulmonary disease, biomarkers of inflammation such as IL-2, IL-6, IL-8, and eotaxin may add additional modest predictive value on top of clinical variables alone.
    • The value of by-catch data: how species-specific surveys can serve non-target species

      Mazzamuto, Maria Vittoria; Lo Valvo, Mario; Anile, Stefano; Univ Arizona, Sch Nat Resources & Environm (SPRINGER, 2019-08-08)
      Camera trapping has a wide range of research application, but, while research designs are often focused on the study of a single focal species, cameras can also record other non-target species. Occupancy modeling using by-catch data can be a valuable resource to gain information on these species maximizing the scientific effort and efficiency of wildlife surveys. In this study, we used by-catch data from a European wildcat (Felis silvestris silvestris) survey in Southern Italy to assess the habitat covariates determinant for the occupancy of the crested porcupine (Hystrix cristata). We recorded 33 detections at 17 out of 51 cameras (naive occupancy = 0.33). The best models fitted the data well, and porcupine occupancy estimate was 0.58 (SE +/- 0.09) with a detection probability of 0.11 (SE +/- 0.03). Average model showed that woodlands and number of shrub patches increased porcupine occupancy, while the reverse was true for altitude. Our results have improved the insights on the habitat use and ecological needs of this understudied species, and it is the first study that develops occupancy models for the porcupine using the presence/absence data obtained from a camera trap survey. Our study is an example of how camera trap surveys are often an under-exploited source of valuable information on a wider spectrum of sympatric species beyond the focal species for which camera traps were deployed. Minimum requirements for a camera trap survey to provide robust occupancy estimates for non-target species are discussed.
    • Vampirovibrio chlorellavorus draft genome sequence, annotation, and preliminary characterization of pathogenicity determinants

      Hovde, Blake T.; Steichen, Seth A.; Starkenburg, Shawn R.; Brown, Judith K.; Univ Arizona, Sch Plant Sci (WILEY, 2019-07-17)
      Vampirovibrio chlorellavorus is recognized as a pathogen of commercially-relevant Chlorella species. Algal infection and total loss of productivity (biomass) often occurs when susceptible algal hosts are cultivated in outdoor open pond systems. The pathogenic life cycle of this bacterium has been inferred from laboratory and field observations, and corroborated in part by the genomic analyses for two Arizona isolates recovered from an open algal reactor. V. chlorellavorus predation has been reported to occur in geographically- and environmentally-diverse conditions. Genomic analyses of these and additional field isolates is expected to reveal new information about the extent of ecological diversity and genes involved in host-pathogen interactions. The draft genome sequences for two isolates of the predatory V. chlorellavorus (Cyanobacteria; Ca. Melainabacteria) from an outdoor cultivation system located in the Arizona Sonoran Desert were assembled and annotated. The genomes were sequenced and analyzed to identify genes (proteins) with predicted involvement in predation, infection, and cell death of Chlorella host species prioritized for biofuel production at sites identified as highly suitable for algal production in the southwestern USA. Genomic analyses identified several predicted genes encoding secreted proteins that are potentially involved in pathogenicity, and at least three apparently complete sets of virulence (Vir) genes, characteristic of the VirB-VirD type system encoding the canonical VirB1-11 and VirD4 proteins, respectively. Additional protein functions were predicted suggesting their involvement in quorum sensing and motility. The genomes of two previously uncharacterized V. chlorellavorus isolates reveal nucleotide and protein level divergence between each other, and a previously sequenced V. chlorellavorus genome. This new knowledge will enhance the fundamental understanding of trans-kingdom interactions between a unique cosmopolitan cyanobacterial pathogen and its green microalgal host, of broad interest as a source of harvestable biomass for biofuels or bioproducts.
    • The VANDELS ESO public spectroscopic survey

      McLure, R J; Pentericci, L; Cimatti, A; Dunlop, J S; Elbaz, D; Fontana, A; Nandra, K; Amorin, R; Bolzonella, M; Bongiorno, A; et al. (OXFORD UNIV PRESS, 2018-09)
      VANDELS is a uniquely deep spectroscopic survey of high-redshift galaxies with the VIMOS spectrograph on ESO's Very Large Telescope (VLT). The survey has obtained ultradeep optical (0.48 < lambda < 1.0 mu m) spectroscopy of similar or equal to 2100 galaxies within the redshilt interval 1.0 <= z <= 7.0, over a total area of similar or equal to 0.2 deg(2) centred on the CANDLES Ultra Deep Survey and Chandra Deep Field South fields. Based on accurate photometric redshift. pre-selection, 85 per cent of the galaxies targeted by VANDELS were selected to be at z >= 3. Exploiting the red sensitivity of the refurbished VIMOS spectrograph, the fundamental aim of the survey is to provide the high-signal-to-noise ratio spectra necessary to measure key physical properties such as stellar population ages, masses, metallicities, and outflow velocities from detailed absorption-line studies. Using integration times calculated to produce an approximately constant signal-to-noise ratio (20 < t(int) < 80 h), the VANDELS survey targeted: (a) bright star-forming galaxies at 2.4 <= z <= 5.5, (b) massive quiescent galaxies at 1.0 <= z <= 2.5, (c) fainter star-forming galaxies at 3.0 <= z <= 7.0, and (d) X-ray/Spitzer-selected active galactic nuclei and Herschel-detected galaxies. By targeting two extragalactic survey fields with superb multiwavelength imaging data, VANDELS will produce a unique legacy data set for exploring the physics underpinning high-redshift. galaxy evolution. In this paper, we provide an overview of the VANDFTS survey designed to support the science exploitation of the first ESO public data release, focusing on the scientific motivation, survey design, and target selection.
    • The VANDELS ESO public spectroscopic survey: Observations and first data release

      Pentericci, L.; McLure, R. J.; Garilli, B.; Cucciati, O.; Franzetti, P.; Iovino, A.; Amorin, R.; Bolzonella, M.; Bongiorno, A.; Carnall, A. C.; et al. (EDP SCIENCES S A, 2018-09-03)
      This paper describes the observations and the first data release (DR1) of the ESO public spectroscopic survey "VANDELS, a deep VIMOS survey of the CANDELS CDFS and UDS fields". The main targets of VANDELS are star-forming galaxies at redshift 2.4 < z < 5.5, an epoch when the Universe had not yet reached 20% of its current age, and massive passive galaxies in the range 1 < z < 2.5. By adopting a strategy of ultra-long exposure times, ranging from a minimum of 20 h to a maximum of 80 h per source, VANDELS is specifically designed to be the deepest-ever spectroscopic survey of the high-redshift Universe. Exploiting the red sensitivity of the refurbished VIMOS spectrograph, the survey is obtaining ultra-deep optical spectroscopy covering the wavelength range 4800-10 000 angstrom with a sufficiently high signal-to-noise ratio to investigate the astrophysics of high-redshift galaxy evolution via detailed absorption line studies of well-defined samples of high-redshift galaxies. VANDELS-DR1 is the release of all medium-resolution spectroscopic data obtained during the first season of observations, on a 0.2 square degree area centered around the CANDELS-CDFS (Chandra deep-field south) and CANDELS-UDS (ultra-deep survey) areas. It includes data for all galaxies for which the total (or half of the total) scheduled integration time was completed. The DR1 contains 879 individual objects, approximately half in each of the two fields, that have a measured redshift, with the highest reliable redshifts reaching z(spec) similar to 6. In DR1 we include fully wavelength-calibrated and flux-calibrated 1D spectra, the associated error spectrum and sky spectrum, and the associated wavelength-calibrated 2D spectra. We also provide a catalog with the essential galaxy parameters, including spectroscopic redshifts and redshift quality flags measured by the collaboration. We present the survey layout and observations, the data reduction and redshift measurement procedure, and the general properties of the VANDELS-DR1 sample. In particular, we discuss the spectroscopic redshift distribution and the accuracy of the photometric redshifts for each individual target category, and we provide some examples of data products for the various target types and the different quality flags. All VANDELS-DR1 data are publicly available and can be retrieved from the ESO archive. Two further data releases are foreseen in the next two years, and a final data release is currently scheduled for June 2020, which will include an improved rereduction of the entire spectroscopic data set.
    • The vanishing cryovolcanoes of Ceres

      Sori, Michael M.; Byrne, Shane; Bland, Michael T.; Bramson, A. M.; Ermakov, Anton I.; Hamilton, Christopher W.; Otto, Katharina A.; Ruesch, Ottaviano; Russell, C. T.; Univ Arizona, Lunar & Planetary Lab; et al. (AMER GEOPHYSICAL UNION, 2017-02-16)
      Ahuna Mons is a 4 km tall mountain on Ceres interpreted as a geologically young cryovolcanic dome. Other possible cryovolcanic features are more ambiguous, implying that cryovolcanism is only a recent phenomenon or that other cryovolcanic structures have been modified beyond easy identification. We test the hypothesis that Cerean cryovolcanic domes viscously relax, precluding ancient domes from recognition. We use numerical models to predict flow velocities of Ahuna Mons to be 10-500 m/Myr, depending upon assumptions about ice content, rheology, grain size, and thermal parameters. Slower flow rates in this range are sufficiently fast to induce extensive relaxation of cryovolcanic structures over 10(8)-10(9) years, but gradual enough for Ahuna Mons to remain identifiable today. Positive topographic features, including a tholus underlying Ahuna Mons, may represent relaxed cryovolcanic structures. A composition for Ahuna Mons of >40% ice explains the observed distribution of cryovolcanic structures because viscous relaxation renders old cryovolcanoes unrecognizable.
    • Vaqaye'-e Ettefaqiyeh (1851–1861) and the Education of the Iranian Nation in the Middle of the Nineteenth Century

      Ebrahimian, Mojtaba; Univ Arizona, Sch Middle Eastern & North African Studies (ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, 2020-01-13)
      This article contributes to the discussions of the genesis of the print media in Iran by analysing the first official weekly gazette published for ten years in the country. It first, examines the present scholarship on Vaqaye'-e Ettefaqiyeh, which disregards the official Qajar gazette as a mouthpiece of the government, portrays it as only one of the administrative reforms of Amir Kabir, or considers it a precursor to more noteworthy print media of the turn of the twentieth century. Then, building upon and expanding such scholarship, this article demonstrates that as the only form of print media in Iran, the Qajar gazette firstly, contributed to the popularisation of reading in Iran, and secondly, introduced Iranians, both those who bought and read it as well as those who heard it read aloud in public spaces, to the current proceedings of the Qajar court, historical developments outside Iran, and most importantly, modern technological and democratic developments in Europe and the New World.
    • Variability in GRMHD Simulations of Sgr A*: Implications for EHT Closure Phase Observations

      Medeiros, Lia; Chan, Chi-Kwan; Özel, Feryal; Psaltis, Dimitrios; Kim, Junhan; Marrone, Daniel P.; Sa̧dowski, Aleksander; Univ Arizona, Steward Observ; Univ Arizona, Dept Astron (IOP PUBLISHING LTD, 2017-07-19)
      Closure phases along different baseline triangles carry a large amount of information regarding the structures of the images of black holes in interferometric observations with the Event Horizon Telescope. We use long time span, high cadence, GRMHD+radiative transfer models of Sgr A* to investigate the expected variability of closure phases in such observations. We find that, in general, closure phases along small baseline triangles show little variability, except in the cases when one of the triangle vertices crosses one of the small regions of low visibility amplitude. The closure phase variability increases with the size of the baseline triangle, as larger baselines probe the small-scale structures of the images, which are highly variable. On average, the funnel-dominated MAD models show less closure phase variability than the disk-dominated SANE models, even in the large baseline triangles, because the images from the latter are more sensitive to the turbulence in the accretion flow. Our results suggest that image reconstruction techniques need to explicitly take into account the closure phase variability, especially if the quality and quantity of data allow for a detailed characterization of the nature of variability. This also implies that, if image reconstruction techniques that rely on the assumption of a static image are utilized, regions of the u-v space that show a high level of variability will need to be identified and excised.