• The 1.4 mm Core of Centaurus A: First VLBI Results with the South Pole Telescope

      Kim, Junhan; Marrone, Daniel P.; Roy, Alan L.; Wagner, Jan; Asada, Keiichi; Beaudoin, Christopher; Blanchard, Jay; Carlstrom, John E.; Chen, Ming-Tang; Crawford, Thomas M.; et al. (IOP PUBLISHING LTD, 2018-07-10)
      Centaurus A (Cen A) is a bright radio source associated with the nearby galaxy NGC 5128 where high-resolution radio observations can probe the jet at scales of less than a light day. The South Pole Telescope (SPT) and the Atacama Pathfinder Experiment performed a single-baseline very-long-baseline interferometry (VLBI) observation of Cen A in 2015 January as part of VLBI receiver deployment for the SPT. We measure the correlated flux density of Cen A at a wavelength of 1.4 mm on a similar to 7000 km (5 G lambda) baseline. Ascribing this correlated flux density to the core, and with the use of a contemporaneous short-baseline flux density from a Submillimeter Array observation, we infer a core brightness temperature of 1.4 x 10(11) K. This is close to the equipartition brightness temperature, where the magnetic and relativistic particle energy densities are equal. Under the assumption of a circular Gaussian core component, we derive an upper limit to the core size phi = 34.0 +/- 1.8 mu as, corresponding to 120 Schwarzschild radii for a black hole mass of 5.5 x. 10(7) M-circle dot.
    • A 100,000 Scale Factor Radar Range

      Blanche, Pierre-Alexandre; Neifeld, Mark; Peyghambarian, Nasser; Univ Arizona, Coll Opt Sci (NATURE PUBLISHING GROUP, 2017-12-19)
      The radar cross section of an object is an important electromagnetic property that is often measured in anechoic chambers. However, for very large and complex structures such as ships or sea and land clutters, this common approach is not practical. The use of computer simulations is also not viable since it would take many years of computational time to model and predict the radar characteristics of such large objects. We have now devised a new scaling technique to overcome these difficulties, and make accurate measurements of the radar cross section of large items. In this article we demonstrate that by reducing the scale of the model by a factor 100,000, and using near infrared wavelength, the radar cross section can be determined in a tabletop setup. The accuracy of the method is compared to simulations, and an example of measurement is provided on a 1mm highly detailed model of a ship. The advantages of this scaling approach is its versatility, and the possibility to perform fast, convenient, and inexpensive measurements.
    • A 1200+year reconstruction of temperature extremes for the northeastern Mediterranean region

      Klippel, Lara; Krusic, Paul J.; Konter, Oliver; St George, Scott; Trouet, Valerie; Esper, Jan; Univ Arizona, Tree Ring Res Lab (WILEY, 2019-03-30)
      Proxy evidence is necessary to place current temperature and hydroclimatic changes in a long-term context and to assess the full range of natural and anthropogenic climate forcings. Here, we present the first millennium-length reconstruction of late summer (August-September) temperature variability for the Mediterranean region. We compiled 132 maximum latewood density (MXD) tree-ring series of living and relict Pinus heldreichii trees from a network of four high-elevation sites in the Pindus Mountains of Greece. Forty series reach back into the first millennium and the oldest sample dates to 575 CE. At annual to decadal scales, the record correlates significantly with August-September temperatures over the Balkan Peninsula and northeastern Mediterranean (r1950-2014 = 0.71, p < 0.001). We produce two reconstructions emphasizing interannual and decadal scale variance over the past millennium. Analysis of temperature extremes reveals the coldest summers occurred in 1035, 1117, 1217, 1884 and 1959 and the coldest decades were 1061-1070 and 1811-1820. The warmest summers occurred in 1240 and 1474, and the warmest decades were 1141-1150 and 1481-1490. Comparison of this new reconstruction with MXD-based summer temperature reconstructions across Europe reveals synchronized occurrences of extreme cool summers in the northeastern Mediterranean, and an antiphase-relationship with warm summer temperatures over the British Isles and Scandinavia. This temperature dipole is related to anomalies in the latitudinal position of the North Atlantic Jet. Despite the representation of common atmospheric forcing patterns, the occurrence of warm extremes is limited to few events, suggesting potential weaknesses of MXD to record warm temperature anomalies. In addition, we acknowledge problems in the observational data to capture local temperature variability due to small scale topographic differences in this high-elevation landscape. At a broader geographical scale, the occurrence of common cold summer extremes is restricted to years with volcanically induced changes in radiative forcing.
    • The 12C/ 13C Ratio in Sgr B2(N): Constraints for Galactic Chemical Evolution and Isotopic Chemistry

      Halfen, D. T.; Woolf, N. J.; Ziurys, L. M.; Univ Arizona, Dept Chem & Biochem; Univ Arizona, Dept Astron, Arizona Radio Observ (IOP PUBLISHING LTD, 2017-08-22)
      A study has been conducted of 12C/13C ratios in five complex molecules in the Galactic center. H2CS, CH3CCH, NH2CHO, CH2CHCN, and CH3CH2CN and their 13C-substituted species have been observed in numerous transitions at 1, 2, and 3 mm, acquired in a spectral-line survey of Sgr B2(N), conducted with the telescopes of the Arizona Radio Observatory (ARO). Between 22 and 54 individual, unblended lines for the 12C species and 2–54 for 13C-substituted analogs were modeled in a global radiative transfer analysis. All five molecules were found to consistently exhibit two velocity components near VLSR ∼ 64 and 73 km s−1, with column densities ranging from Ntot ∼ 3 × 1014 − 4 × 1017 cm−2 and ∼2 × 1013 − 1 × 1017 cm−2 for the 12C and 13C species, respectively. Based on 14 different isotopic combinations, ratios were obtained in the range 12C/13C = 15 ± 5 to 33 ± 13, with an average value of 24 ± 7, based on comparison of column densities. These measurements better anchor the 12C/13C ratio at the Galactic center, and suggest a slightly revised isotope gradient of 12C/13C = 5.21(0.52) DGC + 22.6(3.3). As indicated by the column densities, no preferential 13C enrichment was found on the differing carbon sites of CH3CCH, CH2CHCN, and CH3CH2CN. Because of the elevated temperatures in Sgr B2(N), 13C isotopic substitution is effectively “scrambled,” diminishing chemical fractionation effects. The resulting ratios thus reflect stellar nucleosynthesis and Galactic chemical evolution, as is likely the case for most warm clouds.
    • 12C/13C isotopic ratios in red-giant stars of the open cluster NGC 6791

      Szigeti, László; Mészáros, Szabolcs; Smith, Verne V; Cunha, Katia; Lagarde, Nadège; Charbonnel, Corinne; García-Hernández, D A; Shetrone, Matthew; Pinsonneault, Marc; Allende Prieto, Carlos; et al. (OXFORD UNIV PRESS, 2018-03)
      Carbon isotope ratios, along with carbon and nitrogen abundances, are derived in a sample of 11 red-giant members of one of the most metal-rich clusters in the Milky Way, NGC 6791. The selected red-giants have a mean metallicity and standard deviation of [Fe/H] = +0.39 +/- 0.06 (Cunha et al. 2015). We used high-resolution H-band spectra obtained by the SDSS-IV Apache Point Observatory Galactic Evolution Experiment. The advantage of using high-resolution spectra in the H band is that lines of CO are well represented and their line profiles are sensitive to the variation of C-12/C-13. Values of the C-12/C-13 ratio were obtained from a spectrum synthesis analysis. The derived C-12/C-13 ratios varied between 6.3 and 10.6 in NGC 6791, in agreement with the final isotopic ratios from thermohaline-induced mixing models. The ratios derived here are combined with those obtained for more metal poor red-giants from the literature to examine the correlation between C-12/C-13, mass, metallicity, and evolutionary status.
    • The 13th Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory

      Albareti, Franco D.; Prieto, Carlos Allende; Almeida, Andres; Anders, Friedrich; Anderson, Scott; Andrews, B.; Aragón-Salamanca, Alfonso; Argudo-Fernández, Maria; Armengaud, Eric; Aubourg, Eric; et al. (IOP PUBLISHING LTD, 2017-12-08)
      The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in 2014 July. It pursues three core programs: the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2), Mapping Nearby Galaxies at APO (MaNGA), and the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). As well as its core program, eBOSS contains two major subprograms: the Time Domain Spectroscopic Survey (TDSS) and the SPectroscopic IDentification of ERosita Sources (SPIDERS). This paper describes the first data release from SDSS-IV, Data Release 13 (DR13). DR13 makes publicly available the first 1390 spatially resolved integral field unit observations of nearby galaxies from MaNGA. It includes new observations from eBOSS, completing the Sloan Extended QUasar, Emission-line galaxy, Luminous red galaxy Survey (SEQUELS), which also targeted variability-selected objects and X-ray-selected objects. DR13 includes new reductions of the SDSS-III BOSS data, improving the spectrophotometric calibration and redshift classification, and new reductions of the SDSS-III APOGEE-1 data, improving stellar parameters for dwarf stars and cooler stars. DR13 provides more robust and precise photometric calibrations. Value-added target catalogs relevant for eBOSS, TDSS, and SPIDERS and an updated red-clump catalog for APOGEE are also available. This paper describes the location and format of the data and provides references to important technical papers. The SDSS web site, http://www.sdss.org, provides links to the data, tutorials, examples of data access, and extensive documentation of the reduction and analysis procedures. DR13 is the first of a scheduled set that will contain new data and analyses from the planned similar to 6 yr operations of SDSS-IV.
    • A 15-year record of CO emissions constrained by MOPITT CO observations

      Jiang, Zhe; Worden, John R.; Worden, Helen; Deeter, Merritt; Jones, Dylan B. A.; Arellano, Avelino F.; Henze, Daven K.; Univ Arizona, Dept Hydrol & Atmospher Sci (COPERNICUS GESELLSCHAFT MBH, 2017-04-06)
      Long-term measurements from satellites and surface stations have demonstrated a decreasing trend of tropospheric carbon monoxide (CO) in the Northern Hemisphere over the past decade. Likely explanations for this decrease include changes in anthropogenic, fires, and/or biogenic emissions or changes in the primary chemical sink hydroxyl radical (OH). Using remotely sensed CO measurements from the Measurement of Pollution in the Troposphere (MOPITT) satellite instrument, in situ methyl chloroform (MCF) measurements from the World Data Centre for Greenhouse Gases (WDCGG) and the adjoint of the GEOS-Chem model, we estimate the change in global CO emissions from 2001 to 2015. We show that the loss rate of MCF varied by 0.2 % in the past 15 years, indicating that changes in global OH distributions do not explain the recent decrease in CO. Our two-step inversion approach for estimating CO emissions is intended to mitigate the effect of bias errors in the MOPITT data as well as model errors in transport and chemistry, which are the primary factors contributing to the uncertainties when quantifying CO emissions using these remotely sensed data. Our results confirm that the decreasing trend of tropospheric CO in the Northern Hemisphere is due to decreasing CO emissions from anthropogenic and biomass burning sources. In particular, we find decreasing CO emissions from the United States and China in the past 15 years, and unchanged anthropogenic CO emissions from Europe since 2008. We find decreasing trends of biomass burning CO emissions from boreal North America, boreal Asia and South America, but little change over Africa. In contrast to prior results, we find that a positive trend in CO emissions is likely for India and southeast Asia.
    • 16S rRNA gene sequencing on a benchtop sequencer: accuracy for identification of clinically important bacteria.

      Watts, G S; Youens-Clark, K; Slepian, M J; Wolk, D M; Oshiro, M M; Metzger, G S; Dhingra, D; Cranmer, L D; Hurwitz, B L; Univ Arizona, Ctr Canc; et al. (WILEY, 2017-12-01)
      Test the choice of 16S rRNA gene amplicon and data analysis method on the accuracy of identification of clinically important bacteria utilizing a benchtop sequencer. Nine 16S rRNA amplicons were tested on an Ion Torrent PGM to identify 41 strains of clinical importance. The V1-V2 region identified 40 of 41 isolates to the species level. Three data analysis methods were tested, finding that the Ribosomal Database Project's SequenceMatch outperformed BLAST and the Ion Reporter Metagenomics analysis pipeline. Lastly, 16S rRNA gene sequencing mixtures of four species through a six log range of dilution showed species were identifiable even when present as 0·1% of the mixture. Sequencing the V1-V2 16S rRNA gene region, made possible by the increased read length Ion Torrent PGM sequencer's 400 base pair chemistry, may be a better choice over other commonly used regions for identifying clinically important bacteria. In addition, the SequenceMatch algorithm, freely available from the Ribosomal Database Project, is a good choice for matching filtered reads to organisms. Lastly, 16S rRNA gene sequencing's sensitivity to the presence of a bacterial species at 0·1% of a mixture suggests it has sufficient sensitivity for samples in which important bacteria may be rare. We have validated 16S rRNA gene sequencing on a benchtop sequencer including simple mixtures of organisms; however, our results highlight deficits for clinical application in place of current identification methods.
    • 17-β-Estradiol induces spreading depression and pain behavior in alert female rats

      Sandweiss, Alexander J.; Cottier, Karissa E.; McIntosh, Mary I.; Dussor, Gregory; Davis, Thomas P.; Vanderah, Todd W.; Largent-Milnes, Tally M.; Univ Arizona, Coll Med, Dept Pharmacol (IMPACT JOURNALS LLC, 2017-12-12)
      Aims: Test the putative contribution of 17-beta-estradiol in the development of spreading depression (SD) events and head pain in awake, non-restrained rats. Main Methods: Female, Sprague-Dawley rats were intact or underwent ovariectomy followed one week later by surgery to place electrodes onto the dura to detect epidural electroencephalographic activity (dEEG). dEEG activity was recorded two days later for 12 hours after systemic administration of 17-beta-estradiol (180 mu g/kg, i.p.). A separate set of rats were observed for changes in exploratory, ambulatory, fine, and rearing behaviors; periorbital allodynia was also assessed. Key Findings: A bolus of 17-beta-estradiol significantly elevated serum estrogen levels, increased SD episodes over a 12-hour recording period and decreased rearing behaviors in ovariectomized rats. Pre-administration of ICI 182,780, an estrogen receptor antagonist, blocked 17-beta-estradiol-evoked SD events and pain behaviors; similar results were observed when the antimigraine therapeutic sumatriptan was used. Significance: These data indicate that an estrogen receptor-mediated mechanism contributes to SD events in ovariectomized rats and pain behaviors in both ovariectomized -and intact-rats. This suggests that estrogen plays a different role in each phenomenon of migraine where intense fluctuations in concentration may influence SD susceptibility. This is the first study to relate estrogen peaks to SD development and pain behaviors in awake, freely moving female rats, establishing a framework for future preclinical migraine studies.
    • 197 CANDIDATES AND 104 VALIDATED PLANETS IN K2's FIRST FIVE FIELDS

      Crossfield, Ian J. M.; Ciardi, David R.; Petigura, Erik; Sinukoff, Evan; Schlieder, Joshua E.; Howard, Andrew W.; Beichman, Charles A.; Isaacson, Howard T.; Dressing, Courtney D.; Christiansen, Jessie L.; et al. (IOP PUBLISHING LTD, 2016-09-02)
      We present 197 planet candidates discovered using data from the first year of the NASA K2 mission (Campaigns 0-4), along with the results of an intensive program of photometric analyses, stellar spectroscopy, high-resolution imaging, and statistical validation. We distill these candidates into sets of 104 validated planets (57 in multi-planet systems), 30 false positives, and 63 remaining candidates. Our validated systems span a range of properties, with median values of R-P = 2.3 R-circle plus, P = 8.6 days, T-eff = 5300 K, and Kp = 12.7 mag. Stellar spectroscopy provides precise stellar and planetary parameters for most of these systems. We show that K2 has increased by 30% the number of small planets known to orbit moderately bright stars (1-4 R-circle plus, Kp = 9-13. mag). Of particular interest are 76 planets smaller than 2 R-circle plus, 15 orbiting stars brighter than Kp = 11.5. mag, 5 receiving Earth-like irradiation levels, and several multi-planet systems-including 4 planets orbiting the M dwarf K2-72 near mean-motion resonances. By quantifying the likelihood that each candidate is a planet we demonstrate that our candidate sample has an overall false positive rate of 15%-30%, with rates substantially lower for small candidates (<2 R-circle plus) and larger for candidates with radii >8 R-circle plus and/or with P < 3 days. Extrapolation of the current planetary yield suggests that K2 will discover between 500 and 1000 planets in its planned four-year mission, assuming sufficient follow-up resources are available. Efficient observing and analysis, together with an organized and coherent follow-up strategy, are essential for maximizing the efficacy of planet-validation efforts for K2, TESS, and future large-scale surveys.
    • 1H, 15N and 13C sequence specific backbone assignment of the vanadate inhibited hematopoietic tyrosine phosphatase

      Machado, Luciana E. S. F.; Page, Rebecca; Peti, Wolfgang; Univ Arizona, Dept Chem & Biochem (SPRINGER, 2018-04)
      The sequence-specific backbone assignment of hematopoietic protein tyrosine phosphatase (HePTP; PTPN7) in presence of vanadate has been determined, based on triple-resonance experiments using uniformly [C-13,N-15]-labeled protein. These assignments facilitate further studies of HePTP in the presence of inhibitors to target leukemia and provide further insights into the function of protein tyrosine phosphatases.
    • 1–2.4 μm Near-IR Spectrum of the Giant Planet β Pictoris b Obtained with the Gemini Planet Imager

      Chilcote, Jeffrey; Pueyo, Laurent; De Rosa, Robert J.; Vargas, Jeffrey; Macintosh, Bruce; Bailey, Vanessa P.; Barman, Travis S.; Bauman, Brian; Bruzzone, Sebastian; Bulger, Joanna; et al. (IOP PUBLISHING LTD, 2017-03-28)
      Using the Gemini Planet Imager located at Gemini South, we measured the near-infrared (1.0-2.4 mu m) spectrum of the planetary companion to the nearby, young star beta. Pictoris. We compare the spectrum obtained with currently published model grids and with known substellar objects and present the best matching models as well as the best matching observed objects. Comparing the empirical measurement of the bolometric luminosity to evolutionary models, we find a mass of 12.9. +/- 0.2. M-Jup, an effective temperature of 1724. +/- 15 K, a radius of 1.46. +/- 0.01. R-Jup, and a surface gravity of log g = 4.18. 0.01 [dex] (cgs). The stated uncertainties are statistical errors only, and do not incorporate any uncertainty on the evolutionary models. Using atmospheric models, we find an effective temperature of 1700-1800 K and a surface gravity of log g = 3.5-4.0 [dex] depending upon the model. These values agree well with other publications and with "hot-start" predictions from planetary evolution models. Further, we find that the spectrum of beta Pic. b best matches a low surface gravity L2. +/- 1 brown dwarf. Finally, comparing the spectrum to field brown dwarfs, we find the the spectrum best matches 2MASS J04062677- 381210 and 2MASS J03552337 + 1133437.
    • 2-D LDPC Codes and Joint Detection and Decoding for Two-Dimensional Magnetic Recording

      Matcha, Chaitanya Kumar; Roy, Shounak; Bahrami, Mohsen; Vasic, Bane; Srinivasa, Shayan Garani; Univ Arizona, Dept Elect & Comp Engn (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018-02)
      Two-dimensional magnetic recording (TDMR) is a promising technology for boosting areal densities (ADs) using sophisticated signal processing algorithms within a systems framework. The read/write channel architectures have to effectively tackle 2-D inter-symbol interference (ISI), 2-D synchronization errors, media and electronic noise sources, as well as thermal asperities resulting in burst erasures. The 1-D low-density parity check (LDPC) codes are well studied to correct large 1-D burst errors/erasures. However, such 1-D LDPC codes are not suitable for correcting 2-D burst errors/erasures due to the 2-D span of errors. In this paper, we propose construction of a native 2-D LDPC code to effectively correct 2-D burst erasures. We also propose a joint detection and decoding engine based on the generalized belief propagation algorithm to simultaneously handle 2-D ISI, as well as correct bit/burst errors for TDMR channels. This paper is novel in two aspects: 1) we propose the construction of native 2-D LDPC codes to correct large 2-D burst erasures and 2) we develop a 2-D joint signal detection-decoder engine that incorporates 2-D ISI constraints, and modulation code constrains along with LDPC decoding. The native 2-D LDPC code can correct >20% more burst erasures compared with the 1-D LDPC code over a 128 x 256 2-D page of detected bits. Also, the proposed algorithm is observed to achieve a signal-to-noise ratio gain of >0.5 dB in bit error rate performance (translating to 10% increase in ADs around the 1.8 Tb/in(2) regime with grain sizes of 9 nm) as compared with a decoupled detector-decoder system configuration over a small 2-D LDPC code of size 16 x 16. The efficacy of our proposed algorithm and system architecture is evaluated by assessing AD gains via simulations for a TDMR configuration comprising of a 2-D generalized partial response over the Voronoi media model assuming perfect 2-D synchronization.
    • The 2014–2017 outburst of the young star ASASSN-13db

      Sicilia-Aguilar, A.; Oprandi, A.; Froebrich, D.; Fang, M.; Prieto, J. L.; Stanek, K.; Scholz, A.; Kochanek, C. S.; Henning, Th.; Gredel, R.; et al. (EDP SCIENCES S A, 2017-11-24)
      Context. Accretion outbursts are key elements in star formation. ASASSN-13db is a M5-type star with a protoplanetary disk, the lowest-mass star known to experience accretion outbursts. Since its discovery in 2013, it has experienced two outbursts, the second of which started in November 2014 and lasted until February 2017. Aims. We explore the photometric and spectroscopic behavior of ASASSN-13db during the 2014-2017 outburst. Methods. We use high- and low-resolution spectroscopy and time-resolved photometry from the ASAS-SN survey, the LCOGT and the Beacon Observatory to study the light curve of ASASSN-13db and the dynamical and physical properties of the accretion flow. Results. The 2014-2017 outburst lasted for nearly 800 days. A 4.15 d period in the light curve likely corresponds to rotational modulation of a star with hot spot(s). The spectra show multiple emission lines with variable inverse P-Cygni profiles and a highly variable blue-shifted absorption below the continuum. Line ratios from metallic emission lines (Fe I/Fe II, Ti I/Ti II) suggest temperatures of similar to 5800-6000 K in the accretion flow. Conclusions. Photometrically and spectroscopically, the 2014-2017 event displays an intermediate behavior between EXors and FUors. The accretion rate (<(M)over dot> = 1-3 x 10(-7) M-circle dot/yr), about two orders of magnitude higher than the accretion rate in quiescence, is not significantly different from the accretion rate observed in 2013. The absorption features in the spectra suggest that the system is viewed at a high angle and drives a powerful, non-axisymmetric wind, maybe related to magnetic reconnection. The properties of ASASSN-13db suggest that temperatures lower than those for solar-type stars are needed for modeling accretion in very-low-mass systems. Finally, the rotational modulation during the outburst reveals that accretion-related structures settle after the beginning of the outburst and can be relatively stable and long-lived. Our work also demonstrates the power of time-resolved photometry and spectroscopy to explore the properties of variable and outbursting stars.
    • 2016 Infectious Diseases Society of America (IDSA) Clinical Practice Guideline for the Treatment of Coccidioidomycosis

      Galgiani, John N.; Ampel, Neil M.; Blair, Janis E.; Catanzaro, Antonino; Geertsma, Francesca; Hoover, Susan E.; Johnson, Royce H.; Kusne, Shimon; Lisse, Jeffrey; MacDonald, Joel D.; et al. (OXFORD UNIV PRESS INC, 2016-09-15)
      It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. Infectious Diseases Society of America considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances. Coccidioidomycosis, also known as San Joaquin Valley fever, is a systemic infection endemic to parts of the southwestern United States and elsewhere in the Western Hemisphere. Residence in and recent travel to these areas are critical elements for the accurate recognition of patients who develop this infection. In this practice guideline, we have organized our recommendations to address actionable questions concerning the entire spectrum of clinical syndromes. These can range from initial pulmonary infection, which eventually resolves whether or not antifungal therapy is administered, to a variety of pulmonary and extrapulmonary complications. Additional recommendations address management of coccidioidomycosis occurring for special at-risk populations. Finally, preemptive management strategies are outlined in certain at-risk populations and after unintentional laboratory exposure.
    • The 2016 June Optical and Gamma-Ray Outburst and Optical Microvariability of the Blazar 3C 454.3

      Weaver, Zachary R.; Balonek, Thomas J.; Jorstad, Svetlana G.; Marscher, Alan P.; Larionov, Valeri M.; Smith, Paul S.; Boni, Samantha J.; Borman, George A.; Chapman, K. J.; Jenks, Leah G.; et al. (IOP PUBLISHING LTD, 2019-04-09)
      The quasar 3C 454.3 underwent a uniquely structured multifrequency outburst in 2016 June. The blazar was observed in the optical R-band by several ground-based telescopes in photometric and polarimetric modes, at gamma-ray frequencies by the Fermi Large Area Telescope, and at 43 GHz with the Very Long Baseline Array. The maximum flux density was observed on 2016 June 24 at both optical and gamma-ray frequencies, reaching S-opt(max) = 18.91 +/- 0.08 mJy and S-gamma(max) = 22.20 +/- 0.18 x 10(-6) ph cm(-2) s(-1), respectively. The 2016 June outburst possessed a precipitous decay at both gamma-ray and optical frequencies, with the source decreasing in flux density by a factor of 4 over a 24 hr period in the R-band. Intraday variability was observed throughout the outburst, with flux density changes between 1 and 5 mJy over the course of a night. The precipitous decay featured statistically significant quasiperiodic microvariability oscillations with an amplitude of similar to 2%-3% about the mean trend and a characteristic period of 36 minutes. The optical degree of polarization jumped from similar to 3% to nearly 20% during the outburst, while the position angle varied by similar to 120 degrees. A knot was ejected from the 43 GHz core on 2016 February 25, moving at an apparent speed nu(app) = 20.3c +/- 0.8c. From the observed minimum timescale of variability tau(min)(opt) approximate to 2 hr and derived Doppler factor delta = 22.6, we find the size of the emission region r less than or similar to 2.6 x 10(15) cm. If the quasiperiodic microvariability oscillations are caused by periodic variations of the Doppler factor of emission from a turbulent vortex, we derive the rotational speed of the vortex to be similar to 0.2c.
    • The 2016 Mw 7.8 Pedernales, Ecuador, Earthquake: Rapid Response Deployment

      Meltzer, Anne; Beck, Susan; Ruiz, Mario; Hoskins, Mariah; Soto‐Cordero, Lillian; Stachnik, Joshua C.; Lynner, Colton; Porritt, Rob; Portner, Daniel; Alvarado, Alexandra; et al. (SEISMOLOGICAL SOC AMER, 2019-05)
      The April 2016 Pedernales earthquake ruptured a 100 km by 40 km segment of the subduction zone along the coast of Ecuador in an M-w 7.8 megathrust event east of the intersection of the Carnegie ridge with the trench. This portion of the subduction zone has ruptured on decadal time scales in similar size and larger earthquakes, and exhibits a range of slip behaviors, variations in segmentation, and degree of plate coupling along strike. Immediately after the earthquake, an international rapid response effort coordinated by the Instituto Geofisico at the Escuela Politecnica Nacional in Quito deployed 55 seismometers and 10 ocean-bottom seismometers above the rupture zone and adjacent areas to record aftershocks. In this article, we describe the details of the U.S. portion of the rapid response and present an earthquake cata-log from May 2016 to May 2017 produced using data recorded by these stations. Aftershocks focus in distinct clusters within and around the rupture area and match spatial patterns observed in long-term seismicity. For the first two and a half months, aftershocks exhibit a relatively sharp cutoff to the north of the mainshock rupture. In early July, an earthquake swarm occurred similar to 100 km to the northeast of the mainshock in the epicentral region of an M-w 7.8 earthquake in 1958. In December, an increase in seismicity occurred similar to 70 km to the northeast of the mainshock in the epicentral region of the 1906 earthquake. Data from the Pedernales earthquake and aftershock sequence recorded by permanent seismic and geodetic networks in Ecuador and the dense aftershock deployment provide an opportunity to examine the persistence of asperities for large to great earthquakes over multiple seismic cycles, the role of asperities and slow slip in subduction-zone megathrust rupture, and the relationship between locked and creeping parts of the subduction interface.
    • 20th century changes in carbon isotopes and water-use efficiency: tree-ring-based evaluation of the CLM4.5 and LPX-Bern models

      Keller, Kathrin M.; Lienert, Sebastian; Bozbiyik, Anil; Stocker, Thomas F.; Churakova (Sidorova), Olga V.; Frank, David C.; Klesse, Stefan; Koven, Charles D.; Leuenberger, Markus; Riley, William J.; et al. (COPERNICUS GESELLSCHAFT MBH, 2017-05-24)
      Measurements of the stable carbon isotope ratio (delta C-13) on annual tree rings offer new opportunities to evaluate mechanisms of variations in photosynthesis and stomatal conductance under changing CO2 and climate conditions, especially in conjunction with process-based biogeochemical model simulations. The isotopic discrimination is indicative of the ratio between the CO2 partial pressure in the intercellular cavities and the atmosphere (c(i)/c(a)) and of the ratio of assimilation to stomatal conductance, termed intrinsic water-use efficiency (iWUE). We performed isotope-enabled simulations over the industrial period with the land biosphere module (CLM4.5) of the Community Earth System Model and the Land Surface Processes and Exchanges (LPX-Bern) dynamic global vegetation model. Results for C3 tree species show good agreement with a global compilation of delta C-13 measurements on leaves, though modeled C-13 discrimination by C3 trees is smaller in arid regions than measured. A compilation of 76 tree-ring records, mainly from Europe, boreal Asia, and western North America, suggests on average small 20th century changes in isotopic discrimination and in c(i)/c(a) and an increase in iWUE of about 27% since 1900. LPX-Bern results match these century-scale reconstructions, supporting the idea that the physiology of stomata has evolved to optimize trade-offs between carbon gain by assimilation and water loss by transpiration. In contrast, CLM4.5 simulates an increase in discrimination and in turn a change in iWUE that is almost twice as large as that revealed by the tree-ring data. Factorial simulations show that these changes are mainly in response to rising atmospheric CO2. The results suggest that the downregulation of c(i)/c(a) and of photosynthesis by nitrogen limitation is possibly too strong in the standard setup of CLM4.5 or that there may be problems associated with the implementation of conductance, assimilation, and related adjustment processes on long-term environmental changes.
    • The 25 parsec local white dwarf population

      Holberg, J. B.; Oswalt, T. D.; Sion, E. M.; McCook, G. P.; Univ Arizona, Lunar & Planetary Lab (OXFORD UNIV PRESS, 2016-11-01)
      We have extended our detailed survey of the local white dwarf population from 20 to 25 pc, effectively doubling the sample volume, which now includes 232 stars. In the process, newstars within 20 pc have been added, a more uniform set of distance estimates as well as improved spectral and binary classifications are available. The present 25 pc sample is estimated to be about 68 per cent complete (the corresponding 20 pc sample is now 86 per cent complete). The space density of white dwarfs is unchanged at 4.8 +/- 0.5 x 10(-3) pc(-3). This new study includes a white dwarf mass distribution and luminosity function based on the 232 stars in the 25 pc sample. We find a significant excess of single stars over systems containing one or more companions (74 per cent versus 26 per cent). This suggests mechanisms that result in the loss of companions during binary system evolution. In addition, this updated sample exhibits a pronounced deficiency of nearby 'Sirius-like' systems. 11 such systems were found within the 20 pc volume versus only one additional system found in the volume between 20 and 25 pc. An estimate of white dwarf birth rates during the last similar to 8 Gyr is derived from individual remnant cooling ages. A discussion of likely ways new members of the local sample may be found is provided.
    • A 2500 deg2 CMB Lensing Map from Combined South Pole Telescope and Planck Data

      Omori, Y.; Chown, R.; Simard, G.; Story, K. T.; Aylor, K.; Baxter, E. J.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; et al. (IOP PUBLISHING LTD, 2017-11-07)
      We present a cosmic microwave background (CMB) lensing map produced from a linear combination of South Pole Telescope (SPT) and Planck temperature data. The 150 GHz temperature data from the 2500 deg(2) SPT-SZ survey is combined with the Planck 143 GHz data in harmonic space to obtain a temperature map that has a broader l coverage and less noise than either individual map. Using a quadratic estimator technique on this combined temperature map, we produce a map of the gravitational lensing potential projected along the line of sight. We measure the auto-spectrum of the lensing potential C-L(phi phi), and compare it to the theoretical prediction for a.CDM cosmology consistent with the Planck 2015 data set, finding a best-fit amplitude of 0.95(-0.06)(+0.06) (stat.)(-0.01)(+0.01)+ (sys.). The null hypothesis of no lensing is rejected at a significance of 24 sigma. One important use of such a lensing potential map is in cross-correlations with other dark matter tracers. We demonstrate this cross-correlation in practice by calculating the cross-spectrum, C-L(phi) G, between the SPT+ Planck lensing map and Wide-field Infrared Survey Explorer (WISE) galaxies. We fit C-L(phi G) to a power law of the form p(L) = a(L/L-0)(-b) with a, L-0, and b fixed, and find eta(phi G) = C-L(phi G)/p(L) = 0.94(-0.04)(+0.04), which is marginally lower, but in good agreement with eta(phi G) = 1.00-(+0.02)(0.01), the best-fit amplitude for the cross-correlation of Planck-2015 CMB lensing and WISE galaxies over similar to 67% of the sky. The lensing potential map presented here will be used for cross-correlation studies with the Dark Energy Survey, whose footprint nearly completely covers the SPT 2500 deg(2) field.