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Sample records for chasing highly obscured

  1. Three steps to the CIELO: VO and high-resolution spectroscopy chase the origin of soft X-rays in obscured AGN

    NASA Astrophysics Data System (ADS)

    Guainazzi, M.; Bianchi, S.

    The origin of the soft X-ray emission in obscured Active Galactic Nuclei AGN is still largely unknown despite important progress made possible by recent measurements with Chandra and XMM-Newton Our understanding of the evolution of accretion onto supermassive black holes and of its interaction with gas and stars in the dense nuclear environment would receive a dramatic burst by the solution of this mystery In this paper we will a show why high-resolution X-ray spectroscopy is crucial to the solution of this issue b present CIELO the first catalogue of soft X-ray emission lines in obscured AGN 80 sources built from observations of the Reflection Grating Spectrometer RGS on-board XMM-Newton c discuss the implementation of the IVOA Line Data Model in VO tools such as the SED builder VOSpec and its application to CIELO The combination of the unprecedented RGS sensitivity in the soft X-ray regime and of the VO protocols power leads us to be closer than ever to unveiling the nature of soft X-ray emission in obscured AGN

  2. Obscured AGN at High Redshift

    NASA Technical Reports Server (NTRS)

    Stern, Daniel

    2008-01-01

    This viewgraph presentation reviews the obscured sources of Active Galactic Nuclei (AGN) in the universe at high redshift. The cosmic X-ray background, unified models of AGN and clues to galaxy formation/evolution is the motivation for this study.

  3. FE Features in Highly Obscured AGN

    NASA Technical Reports Server (NTRS)

    Schachter, Jonathan F.

    1999-01-01

    This final report is a summary of the combined study of ASCA (Advanced Satellite for Cosmology and Astrophysics) observations of NGC 7582 with archival ROSAT HRI (High Resolution Imager) and PSPC (Position Sensitive Proportional Counter) data. These observations were important in that they established that X-ray emission in NGC 7582, the most narrow-line of NLXGs (narrow-line X-ray galaxies), is associated with an AGN (Active Galactic Nuclei). Thus implying that all NLXGs are obscured AGN, as has been hypothesized to explain the X-ray spectral background paradox.

  4. Dust Obscured Blazars as sources of high-energy neutrinos

    NASA Astrophysics Data System (ADS)

    Maggi, G.; de Vries, K. D.; van Eijndhoven, N.

    2016-08-01

    Active Galactic Nuclei (AGN) are believed to be among the most promising sources of the ultra-high-energy cosmic ray flux. A hadronic component which is accelerated in the high energy environment of an AGN immediately implies the production of high-energy neutrinos. Nevertheless, no clear correlation between AGN and the high-energy cosmic-neutrino flux obtained by IceCube has been found so-far, putting strong limits on the neutrino production at AGN. We discuss a specific type of AGN for which an enhanced neutrino production is expected. This specific sub-set is given by AGN with their high-energy jet directed toward Earth, which is obscured by surrounding dust or gas, defining Dust Obscured Blazars. This type of AGN is predicted to have an enhanced neutrino emission due to the interaction of a possible hadronic component inside the AGN-jet with the surrounding matter. From two different galaxy catalogs, we have selected a sample of nearby sources with the characteristics of Dust Obscured Blazars. This selection is based on observations in the X-ray and radio bands. The data is consequently used to investigate the column density of the surrounding matter, providing an estimate for the neutrino production enhancement due to the nucleon-matter interactions in a beam dump scenario for various dust or gas compositions.

  5. Optically Modulated Fluorescence Bioimaging: Visualizing Obscured Fluorophores in High Background

    PubMed Central

    2015-01-01

    Conspectus Fluorescence microscopy and detection have become indispensible for understanding organization and dynamics in biological systems. Novel fluorophores with improved brightness, photostability, and biocompatibility continue to fuel further advances but often rely on having minimal background. The visualization of interactions in very high biological background, especially for proteins or bound complexes at very low copy numbers, remains a primary challenge. Instead of focusing on molecular brightness of fluorophores, we have adapted the principles of high-sensitivity absorption spectroscopy to improve the sensitivity and signal discrimination in fluorescence bioimaging. Utilizing very long wavelength transient absorptions of kinetically trapped dark states, we employ molecular modulation schemes that do not simultaneously modulate the background fluorescence. This improves the sensitivity and ease of implementation over high-energy photoswitch-based recovery schemes, as no internal dye reference or nanoparticle-based fluorophores are needed to separate the desired signals from background. In this Account, we describe the selection process for and identification of fluorophores that enable optically modulated fluorescence to decrease obscuring background. Differing from thermally stable photoswitches using higher-energy secondary lasers, coillumination at very low energies depopulates transient dark states, dynamically altering the fluorescence and giving characteristic modulation time scales for each modulatable emitter. This process is termed synchronously amplified fluorescence image recovery (SAFIRe) microscopy. By understanding and optically controlling the dye photophysics, we selectively modulate desired fluorophore signals independent of all autofluorescent background. This shifts the fluorescence of interest to unique detection frequencies with nearly shot-noise-limited detection, as no background signals are collected. Although the fluorescence

  6. Tornado Chasing.

    ERIC Educational Resources Information Center

    Faidley, Warren

    1991-01-01

    Presents the rationale and purposes behind the phenomenon known as storm chasing, as well as the contributions that tornado chasers have made to both scientific knowledge and public safety. Provides statistical information on tornado frequencies and locations and contact addresses for storm chasers. (JJK)

  7. Infants’ perception of chasing

    PubMed Central

    Frankenhuis, Willem E.; House, Bailey; Barrett, H. Clark; Johnson, Scott P.

    2012-01-01

    Two significant questions in cognitive and developmental science are first, whether objects and events are selected for attention based on their features (featural processing) or the configuration of their features (configural processing), and second, how these modes of processing develop. These questions have been addressed in part with experiments focused on infants’ perception of faces, human body shapes, and biological motion of individual agents. Here, we investigate 4- and 10-month-old infants’ (N = 192) attention to social motions, specifically to chasing—a ubiquitous, ancient, and fitness-relevant mode of interaction. We constructed computer-generated animations of chasing that had three properties: acceleration, high turning rates, and attraction (“heat-seeking”). In the first experiment we showed chasing side-by-side with a control display of inanimate, billiard-ball-like motions. Infants strongly preferred attending to chasing. In the next three studies, we systematically investigated the effect of each property in turn (acceleration, turning, and attraction) by showing a display of that property side-by-side with the control display. Infants preferentially attended to acceleration, and to attraction, but not to turning. If infants preferred chasing for its configuration, then the sum of the effect sizes of individual properties should be smaller than their combined effects. That is not what we found: instead, on three measures of visual behavior, the summed effects of individual properties equaled (or exceeded) that of chasing. Moreover, although attraction drew little attention and turning no attention at all, acceleration drew (nearly) as much attention as chasing. Our results thus provide evidence that infants preferred chasing because of its features, not its configuration. PMID:23121710

  8. XMM-Newton spectroscopy of high-redshift Dust Obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Lanzuisi, Giorgio

    2010-10-01

    A population of Dust Obscured Galaxies (DOGs; (F(24um)/F(R)>1000 and F(24um)> 1 mJy) at z>1, likely associated with an obscured phase in the quasar lifetime, has recently been revealed. Redshift distribution, broad-band photometry and bolometric luminosities of DOGs indicate that these systems may represent an early dust-embedded phase of powerful AGN activity. Due to low space density, DOGs are rarely detected even in the deepest X-ray surveys. However, low-quality X-ray spectroscopy has revealed the common presence of highly obscured AGN in their nuclei. XMM-Newton is the ideal telescope to study their largely unexplored X-ray properties. We propose here to obtain a high signal-to-noise X-ray spectrum for two unique, optically-identified DOGs from the Bootes survey.

  9. XMM-Newton spectroscopy of high-redshift Dust Obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Lanzuisi, Giorgio

    2011-10-01

    A population of Dust Obscured Galaxies (DOGs; (F(24um)/F(R)>1000 and F(24um)> 1 mJy) at z>1, associated with an obscured phase in the quasar lifetime, has recently been revealed. Redshift distribution, broad-band photometry and bolometric luminosities indicate that these systems may represent an early dust-embedded phase of AGN activity. Due to low space density, DOGs are rarely detected even in the deepest X-ray surveys. However, low-quality X-ray spectroscopy has revealed the common presence of highly obscured AGN in their nuclei. XMM-Newton is the ideal telescope to study their largely unexplored X-ray properties. We propose here to obtain a high signal-to-noise X-ray spectrum for two unique, optically-identified DOGs from the Bootes survey.

  10. Unveiling the High Energy Obscured Universe: Hunting Collapsed Objects Physics

    NASA Technical Reports Server (NTRS)

    Ubertini, P.; Bazzano, A.; Cocchi, M.; Natalucci, L.; Bassani, L.; Caroli, E.; Stephen, J. B.; Caraveo, P.; Mereghetti, S.; Villa, G.

    2005-01-01

    A large part of energy from space is coming from collapsing stars (SN, Hypernovae) and collapsed stars (black holes, neutron stars and white dwarfs). The peak of their energy release is in the hard-X and gamma-ray wavelengths where photons are insensitive to absorption and can travel from the edge the Universe or the central core of the Galaxy without loosing the primordial information of energy, time signature and polarization. The most efficient process to produce energetic photons is gravitational accretion of matter from a "normal" star onto a collapsed companion (LGxMcollxdMacc/dtx( 1Rdisc)-dMacc/dt x c2), exceeding by far the nuclear reaction capability to generate high energy quanta. Thus our natural laboratory for "in situ" investigations are collapsed objects in which matter and radiation co-exist in extreme conditions of temperature and density due to gravitationally bent geometry and magnetic fields. This is a unique opportunity to study the physics of accretion flows in stellar mass and super-massive Black Holes (SMBHs), plasmoids generated in relativistic jets in galactic microQSOs and AGNs, ionised plasma interacting at the touching point of weakly magnetized NS surface, GRB/Supernovae connection, and the mysterious origins of "dark" GRB and X-ray flash.

  11. Rate of chase-promoted hydrolysis of ATP in the high affinity catalytic site of beef heart mitochondrial ATPase

    SciTech Connect

    Penefsky, H.S.

    1988-05-05

    Incubation of (..gamma..-/sup 32/P)ATP with a molar excess of the soluble, homogeneous ATPase from beef heart mitochondria (F/sub 1/) results in binding of substrate primarily in a single, very high affinity catalytic site and in a slow rate of hydrolysis characteristic of single site catalysis. Subsequent addition of millimolar concentrations of nonradioactive ATP as a cold chase, sufficient to fill catalytic sites on the enzyme, results in an acceleration of hydrolysis of bound radioactive ATP of as much as 10/sup 6/-fold, that is to V/sub max/ rates. For this reason, it was proposed that the high affinity catalytic site is a normal catalytic site on the molecule. This paper shows, in experiments with a rapid mixing-chemical quench apparatus, that hydrolysis of ATP bound in the high affinity catalytic site is accelerated to V/sub max/ rates following addition of 5 ..mu..M ATP as a cold chase. Hydrolysis of bound ATP appears to precede that of the chase. The weight of the available evidence continues to support the original suggestion that the high affinity catalytic site of beef heart F/sub 1/ is a normal catalytic site.

  12. The Most Luminous Heavily Obscured Quasars Have a High Merger Fraction: Morphological Study of WISE-selected Hot Dust-obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Fan, Lulu; Han, Yunkun; Fang, Guanwen; Gao, Ying; Zhang, Dandan; Jiang, Xiaoming; Wu, Qiaoqian; Yang, Jun; Li, Zhao

    2016-05-01

    Previous studies have shown that Wide-field Infrared Survey Explorer-selected hyperluminous, hot dust-obscured galaxies (Hot DOGs) are powered by highly dust-obscured, possibly Compton-thick active galactic nuclei (AGNs). High obscuration provides us a good chance to study the host morphology of the most luminous AGNs directly. We analyze the host morphology of 18 Hot DOGs at z ˜ 3 using Hubble Space Telescope/WFC3 imaging. We find that Hot DOGs have a high merger fraction (62 ± 14%). By fitting the surface brightness profiles, we find that the distribution of Sérsic indices in our Hot DOG sample peaks around 2, which suggests that most Hot DOGs have transforming morphologies. We also derive the AGN bolometric luminosity (˜1014 L ⊙) of our Hot DOG sample by using IR spectral energy distributions decomposition. The derived merger fraction and AGN bolometric luminosity relation is well consistent with the variability-based model prediction. Both the high merger fraction in an IR-luminous AGN sample and relatively low merger fraction in a UV/optical-selected, unobscured AGN sample can be expected in the merger-driven evolutionary model. Finally, we conclude that Hot DOGs are merger-driven and may represent a transit phase during the evolution of massive galaxies, transforming from the dusty starburst-dominated phase to the unobscured QSO phase.

  13. Obscured AGN

    NASA Astrophysics Data System (ADS)

    Barger, Amy

    2014-07-01

    Obscured AGN may correspond to a substantial fraction of the supermassive black hole growth rate. I will present new surveys with the SCUBA-2 instrument on the James Clerk Maxwell Telescope of the Chandra Deep Fields and discuss whether we can distinguish obscured AGN in hard X-ray and radio selected samples using submillimeter observations.

  14. Type 2 Quasars at the heart of dust-obscured galaxies (DOGs) at high z

    NASA Astrophysics Data System (ADS)

    Piconcelli, E.; Lanzuisi, G.; Fiore, F.; Feruglio, C.; Vignali, C.; Salvato, M.; Gruppioni, C.

    2010-07-01

    Dust-obscured galaxies (DOGs) represent a recently-discovered, intriguing class of mid-IR luminous sources at high redshifts. Evidence is mounting that DOGs (selected on the basis of extreme optical/mid-IR color cut and high mid-IR flux level) may represent systems caught in the process of host galaxy formation and intense SMBH growth. Here we report the results of an X-ray spectroscopic survey aimed at studying the X-ray properties of these sources and establishing the fraction of Type 2 quasars among them.

  15. Exposing high-z obscured AGNs in the deepest IR/X-rays surveys

    NASA Astrophysics Data System (ADS)

    Daddi, Emanuele

    2012-01-01

    The identification and study of the elusive population of high redshift obscured AGNs is an important step towards understanding the fundamental phase of black hole growth in the young universe. Here we propose NIR spectroscopy with MOIRCS to confirm and characterize candidate high-z obscured/Compton-thick AGNs found in the deepest Herschel and X-ray surveys. The sample, designed to cover a range of redshifts (1.5 < z < 4), is selected from the GOODS field by use of Herschel+Spitzer (MIR to FIR colors and the presence of power-law MIR emission) and X-ray spectral properties from XMM and Chandra. The MOIRCS data are crucial to fully confirm and exploit our sample. The specific science goals include (a) obtaining independent AGN classifications and luminosities via rest-frame optical spectroscopy; (b) testing for the expected strong outflows in these high bolometric luminosity QSOs; (c) spectroscopically confirming redshifts of objects which currently have only z_phot. In the larger picture, this study will put stronger constraints on the number density of Compton-thick AGNs and on the evolution of supermassive black holes and their host galaxies.

  16. Obscured AGN

    NASA Technical Reports Server (NTRS)

    Ptak, Andrew

    2011-01-01

    Many obscured AGN show evidence of significant starburst emission dominating below 2 keV. Therefore wide-field X-ray surveys sensitive enough to luminosities below approximately 10^42 ergs per second will result in detections of galaxies with contributions of both obscured AGN and starburst emission. We will discuss Bayesian approaches to assessing the relative contribution of each component, minimizing survey biases and using the resultant posterior probabilities for the AGN and starburst components to determine their evolution.

  17. Morphologies of High-Redshift Dust-Obscured Galaxies from Keck Laser Guide Star Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Melbourne, J.; Desai, V.; Armus, Lee; Dey, Arjun; Brand, K.; Thompson, D.; Soifer, B. T.; Matthews, K.; Jannuzi, B. T.; Houck, J. R.

    2008-09-01

    Spitzer MIPS images in the Boötes field of the NOAO Deep Wide-Field Survey have revealed a class of extremely dust-obscured galaxy (DOG) at z ~ 2. The DOGs are defined by very red optical to mid-infrared (IR; observed-frame) colors, R - [24 μm]>14 mag, i.e. f ν(24 μm)/f ν(R)>1000. They are ultra-luminous infrared galaxies with L 8-1000 μm > 1012-1014 L sun, but typically have very faint optical (rest-frame UV) fluxes. We imaged three DOGs with the Keck laser guide star adaptive optics (LGSAO) system, obtaining ~0.06'' resolution in the K'-band. One system was dominated by a point source, while the other two were clearly resolved. Of the resolved sources, one can be modeled as a exponential disk system. The other is consistent with a de Vaucouleurs profile typical of elliptical galaxies. The nonparametric measures of their concentration and asymmetry show the DOGs to be both compact and smooth. The AO images rule out double nuclei with separations of greater than 0.1'' (<1 kpc at z = 2), making it unlikely that ongoing major mergers (mass ratios of 1/3 and greater) are triggering the high-IR luminosities. By contrast, high-resolution images of z ~ 2 SCUBA sources tend to show multiple components and a higher degree of asymmetry. We compare near-IR morphologies of the DOGs with a set of z = 1 luminous infrared galaxies (LIRGs; L IR ~ 1011 L sun) imaged with Keck LGSAO by the Center for Adaptive Optics Treasury Survey. The DOGs in our sample have significantly smaller effective radii, ~1/4 the size of the z = 1 LIRGs, and tend toward higher concentrations. The small sizes and high concentrations may help explain the globally obscured rest-frame blue-to-UV emission of the DOGs.

  18. Millimeter Observations of a Sample of High-Redshift Obscured Quasars

    NASA Astrophysics Data System (ADS)

    Martínez-Sansigre, Alejo; Karim, Alexander; Schinnerer, Eva; Omont, Alain; Smith, Daniel J. B.; Wu, Jingwen; Hill, Gary J.; Klöckner, Hans-Rainer; Lacy, Mark; Rawlings, Steve; Willott, Chris J.

    2009-11-01

    We present observations at 1.2 mm with Max-Planck Millimetre Bolometer Array (MAMBO-II) of a sample of z gsim 2 radio-intermediate obscured quasars, as well as CO observations of two sources with the Plateau de Bure Interferometer. The typical rms noise achieved by the MAMBO observations is 0.55 mJy beam-1 and five out of 21 sources (24%) are detected at a significance of >=3σ. Stacking all sources leads to a statistical detection of langS 1.2 mmrang = 0.96 ± 0.11 mJy and stacking only the non-detections also yields a statistical detection, with langS 1.2 mmrang = 0.51 ± 0.13 mJy. At the typical redshift of the sample, z = 2, 1 mJy corresponds to a far-infrared luminosity L FIR~4 × 1012 L sun. If the far-infrared luminosity is powered entirely by star formation, and not by active galactic nucleus heated dust, then the characteristic inferred star formation rate is ~700 M sun yr-1. This far-infrared luminosity implies a dust mass of M d~3 × 108 M sun, which is expected to be distributed on ~kpc scales. We estimate that such large dust masses on kpc scales can plausibly cause the obscuration of the quasars. Combining our observations at 1.2 mm with mid- and far-infrared data, and additional observations for two objects at 350 μm using SHARC-II, we present dust spectral energy distributions (SEDs) for our sample and derive a mean SED for our sample. This mean SED is not well fitted by clumpy torus models, unless additional extinction and far-infrared re-emission due to cool dust are included. This additional extinction can be consistently achieved by the mass of cool dust responsible for the far-infrared emission, provided the bulk of the dust is within a radius ~2-3 kpc. Comparison of our sample to other samples of z ~ 2 quasars suggests that obscured quasars have, on average, higher far-infrared luminosities than unobscured quasars. There is a hint that the host galaxies of obscured quasars must have higher cool-dust masses and are therefore often found at an

  19. High Redshift Dust Obscured Galaxies, A Morphology-SED Connection Revealed by Keck Adaptive Optics Imaging

    NASA Astrophysics Data System (ADS)

    Melbourne, Jason

    2009-01-01

    Keck Adaptive Optics (AO) K'-band images reveal the morphologies of 15 high redshift (z 2) dust obscured galaxies (DOGs). DOGs are defined by an optical to mid-IR color of fν(24) / fν(R) > 1000, redder than Arp 220 at any redshift. With ultra-luminous infrared luminosities, DOGs are thought to be powered by a combination of AGN and star formation. We use high spatial resolution (0.5 - 1 kpc at these redshifts) AO images to help disentangle the dominant energy source in each DOG and to look for triggers, such as evidence of ongoing mergers. We find evidence for ongoing merging in 10-20% of the sample. We also find a statistically significant correlation between galaxy compactness and 24 micron flux (luminosity), with the brightest DOGs exhibiting more compact morphologies than fainter DOGs. The most diffuse systems tend to show a 1.6 micron stellar bump in their spectral energy distributions redshifted to the Spitzer IRAC bands (4.5 - 8.0 microns). The imaging results lend further support to the idea that the highest luminosity DOGs are AGN dominated (resulting in compact morphology), while the lower luminosity, diffuse, DOGs tend to be star formation dominated.

  20. MILLIMETER OBSERVATIONS OF A SAMPLE OF HIGH-REDSHIFT OBSCURED QUASARS

    SciTech Connect

    Martinez-Sansigre, Alejo; Karim, Alexander; Schinnerer, Eva E-mail: karim@mpia.d

    2009-11-20

    We present observations at 1.2 mm with Max-Planck Millimetre Bolometer Array (MAMBO-II) of a sample of z approx> 2 radio-intermediate obscured quasars, as well as CO observations of two sources with the Plateau de Bure Interferometer. The typical rms noise achieved by the MAMBO observations is 0.55 mJy beam{sup -1} and five out of 21 sources (24%) are detected at a significance of >=3sigma. Stacking all sources leads to a statistical detection of (S{sub 1.2mm}) = 0.96 +- 0.11 mJy and stacking only the non-detections also yields a statistical detection, with (S{sub 1.2mm}) = 0.51 +- 0.13 mJy. At the typical redshift of the sample, z = 2, 1 mJy corresponds to a far-infrared luminosity L{sub FIR}approx4 x 10{sup 12} L{sub sun}. If the far-infrared luminosity is powered entirely by star formation, and not by active galactic nucleus heated dust, then the characteristic inferred star formation rate is approx700 M{sub sun} yr{sup -1}. This far-infrared luminosity implies a dust mass of M{sub d}approx3 x 10{sup 8} M{sub sun}, which is expected to be distributed on approxkpc scales. We estimate that such large dust masses on kpc scales can plausibly cause the obscuration of the quasars. Combining our observations at 1.2 mm with mid- and far-infrared data, and additional observations for two objects at 350 mum using SHARC-II, we present dust spectral energy distributions (SEDs) for our sample and derive a mean SED for our sample. This mean SED is not well fitted by clumpy torus models, unless additional extinction and far-infrared re-emission due to cool dust are included. This additional extinction can be consistently achieved by the mass of cool dust responsible for the far-infrared emission, provided the bulk of the dust is within a radius approx2-3 kpc. Comparison of our sample to other samples of z approx 2 quasars suggests that obscured quasars have, on average, higher far-infrared luminosities than unobscured quasars. There is a hint that the host galaxies of obscured

  1. Obscured quasars at high redshift in the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Strauss, Michael

    2016-08-01

    The SDSS has uncovered a substantial number of luminous quasars with weak continuum, strong narrow lines, and strong evidence for obscuration, at redshifts from 0.4 to 4. I will discuss the selection of such objects and their properties in the optical and infrared. Some of these objects show evidence for significant outflows, with substantial wings in their [OIII] profiles.

  2. Probing highly obscured, self-absorbed galaxy nuclei with vibrationally excited HCN

    NASA Astrophysics Data System (ADS)

    Aalto, S.; Martín, S.; Costagliola, F.; González-Alfonso, E.; Muller, S.; Sakamoto, K.; Fuller, G. A.; García-Burillo, S.; van der Werf, P.; Neri, R.; Spaans, M.; Combes, F.; Viti, S.; Mühle, S.; Armus, L.; Evans, A.; Sturm, E.; Cernicharo, J.; Henkel, C.; Greve, T. R.

    2015-12-01

    We present high resolution (0.̋4) IRAM PdBI and ALMA mm and submm observations of the (ultra) luminous infrared galaxies ((U)LIRGs) IRAS 17208-0014, Arp220, IC 860 and Zw049.057 that reveal intense line emission from vibrationally excited (ν2 = 1) J = 3-2 and 4-3 HCN. The emission is emerging from buried, compact (r< 17-70 pc) nuclei that have very high implied mid-infrared surface brightness > 5 × 1013 L⊙ kpc-2. These nuclei are likely powered by accreting supermassive black holes (SMBHs) and/or hot (>200 K) extreme starbursts. Vibrational, ν2 = 1, lines of HCN are excited by intense 14 μm mid-infrared emission and are excellent probes of the dynamics, masses, and physical conditions of (U)LIRG nuclei when H2 column densities exceed 1024 cm-2. It is clear that these lines open up a new interesting avenue to gain access to the most obscured AGNs and starbursts. Vibrationally excited HCN acts as a proxy for the absorbed mid-infrared emission from the embedded nuclei, which allows for reconstruction of the intrinsic, hotter dust SED. In contrast, we show strong evidence that the ground vibrational state (ν = 0), J = 3-2and 4-3 rotational lines of HCN and HCO+ fail to probe the highly enshrouded, compact nuclear regions owing to strong self- and continuum absorption. The HCN and HCO+ line profiles are double-peaked because of the absorption and show evidence of non-circular motions - possibly in the form of in- or outflows. Detections of vibrationally excited HCN in external galaxies are so far limited to ULIRGs and early-type spiral LIRGs, and we discuss possible causes for this. We tentatively suggest that the peak of vibrationally excited HCN emission is connected to a rapid stage of nuclear growth, before the phase of strong feedback. Based on observations carried out with the IRAM Plateau de Bure and ALMA Interferometers. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). ALMA is a partnership of ESO (representing its member states

  3. How to reveal the mysteries of the most obscured high-energy sources of our Galaxy, discovered by INTEGRAL?

    SciTech Connect

    Chaty, Sylvain

    2007-07-12

    A new type of high-energy binary systems has been revealed by the INTEGRAL satellite. These sources are in the course of being unveiled by means of multi-wavelength optical, near- and mid-infrared observations. Among these sources, two distinct classes are appearing: the first one is constituted of intrinsically obscured high-energy sources, of which IGR J16318-4848 seems to be the most extreme example. The second one is populated by the so-called supergiant fast X-ray transients, with IGR J17544-2619 being the archetype. We report here on multi-wavelength optical to mid-infrared observations of these systems. We show that in the case of the obscured sources our observations suggest the presence of absorbing material (dust and/or cold gas) enshrouding the whole binary system. We then discuss the nature of these two different types of systems.

  4. High precision X-ray log N - log S distributions: implications for the obscured AGN population

    NASA Astrophysics Data System (ADS)

    Mateos, S.; Warwick, R. S.; Carrera, F. J.; Stewart, G. C.; Ebrero, J.; Della Ceca, R.; Caccianiga, A.; Gilli, R.; Page, M. J.; Treister, E.; Tedds, J. A.; Watson, M. G.; Lamer, G.; Saxton, R. D.; Brunner, H.; Page, C. G.

    2008-12-01

    source count distributions than AGN. We find a substantial increase in the relative fraction of hard X-ray sources at higher energies, from ≥55% below 2 keV to ≥77% above 2 keV. However, the majority of sources detected above 4.5 keV still have significant flux below 2 keV. Comparison with predictions from the synthesis models suggest that the models might be overpredicting the number of faint absorbed AGN, which would call for fine adjustment of some model parameters such as the obscured to unobscured AGN ratio and/or the distribution of column densities at intermediate obscuration. Appendices A and B are only available in electronic form at http://www.aanda.org

  5. Blowin' in the Wind: Both "Negative" and "Positive" Feedback in an Obscured High-z Quasar

    NASA Astrophysics Data System (ADS)

    Cresci, G.; Mainieri, V.; Brusa, M.; Marconi, A.; Perna, M.; Mannucci, F.; Piconcelli, E.; Maiolino, R.; Feruglio, C.; Fiore, F.; Bongiorno, A.; Lanzuisi, G.; Merloni, A.; Schramm, M.; Silverman, J. D.; Civano, F.

    2015-01-01

    Quasar feedback in the form of powerful outflows is invoked as a key mechanism to quench star formation in galaxies, preventing massive galaxies to overgrow and producing the red colors of ellipticals. On the other hand, some models are also requiring "positive" active galactic nucleus feedback, inducing star formation in the host galaxy through enhanced gas pressure in the interstellar medium. However, finding observational evidence of the effects of both types of feedback is still one of the main challenges of extragalactic astronomy, as few observations of energetic and extended radiatively driven winds are available. Here we present SINFONI near infrared integral field spectroscopy of XID2028, an obscured, radio-quiet z = 1.59 QSO detected in the XMM-COSMOS survey, in which we clearly resolve a fast (1500 km s-1) and extended (up to 13 kpc from the black hole) outflow in the [O III] lines emitting gas, whose large velocity and outflow rate are not sustainable by star formation only. The narrow component of Hα emission and the rest frame U-band flux from Hubble Space Telescope/Advanced Camera for Surveys imaging enable to map the current star formation in the host galaxy: both tracers independently show that the outflow position lies in the center of an empty cavity surrounded by star forming regions on its edge. The outflow is therefore removing the gas from the host galaxy ("negative feedback"), but also triggering star formation by outflow induced pressure at the edges ("positive feedback"). XID2028 represents the first example of a host galaxy showing both types of feedback simultaneously at work.

  6. BLOWIN' IN THE WIND: BOTH ''NEGATIVE'' AND ''POSITIVE'' FEEDBACK IN AN OBSCURED HIGH-z QUASAR

    SciTech Connect

    Cresci, G.; Mannucci, F.; Mainieri, V.; Brusa, M.; Perna, M.; Lanzuisi, G.; Piconcelli, E.; Feruglio, C.; Fiore, F.; Bongiorno, A.; Maiolino, R.; Merloni, A; Schramm, M.; Silverman, J. D.; Civano, F.

    2015-01-20

    Quasar feedback in the form of powerful outflows is invoked as a key mechanism to quench star formation in galaxies, preventing massive galaxies to overgrow and producing the red colors of ellipticals. On the other hand, some models are also requiring ''positive'' active galactic nucleus feedback, inducing star formation in the host galaxy through enhanced gas pressure in the interstellar medium. However, finding observational evidence of the effects of both types of feedback is still one of the main challenges of extragalactic astronomy, as few observations of energetic and extended radiatively driven winds are available. Here we present SINFONI near infrared integral field spectroscopy of XID2028, an obscured, radio-quiet z = 1.59 QSO detected in the XMM-COSMOS survey, in which we clearly resolve a fast (1500 km s{sup –1}) and extended (up to 13 kpc from the black hole) outflow in the [O III] lines emitting gas, whose large velocity and outflow rate are not sustainable by star formation only. The narrow component of Hα emission and the rest frame U-band flux from Hubble Space Telescope/Advanced Camera for Surveys imaging enable to map the current star formation in the host galaxy: both tracers independently show that the outflow position lies in the center of an empty cavity surrounded by star forming regions on its edge. The outflow is therefore removing the gas from the host galaxy (''negative feedback''), but also triggering star formation by outflow induced pressure at the edges (''positive feedback''). XID2028 represents the first example of a host galaxy showing both types of feedback simultaneously at work.

  7. Pulse-chase analysis for studying protein synthesis and maturation.

    PubMed

    Fritzsche, Susanne; Springer, Sebastian

    2014-11-03

    Pulse-chase analysis is a well-established and highly adaptable tool for studying the life cycle of endogenous proteins, including their synthesis, folding, subunit assembly, intracellular transport, post-translational processing, and degradation. This unit describes the performance and analysis of a radiolabel pulse-chase experiment for following the folding and cell surface trafficking of a trimeric murine MHC class I glycoprotein. In particular, the unit focuses on the precise timing of pulse-chase experiments to evaluate early/short-time events in protein maturation in both suspended and strictly adherent cell lines. The advantages and limitations of radiolabel pulse-chase experiments are discussed, and a comprehensive section for troubleshooting is provided. Further, ways to quantitatively represent pulse-chase results are described, and feasible interpretations on protein maturation are suggested. The protocols can be adapted to investigate a variety of proteins that may mature in very different ways.

  8. MAMBO observations at 240GHz of optically obscured Spitzer sources: source clumps and radio activity at high redshift

    NASA Astrophysics Data System (ADS)

    Andreani, P.; Magliocchetti, M.; de Zotti, G.

    2010-01-01

    Optically very faint (R > 25.5) sources detected by the Spitzer Space Telescope at 24μm represent a very interesting population at redshift z ~ (1.5-3). They exhibit strong clustering properties, implying that they are hosted by very massive haloes, and their mid-infrared emission could be powered by either dust-enshrouded star formation and/or by an obscured active galactic nucleus (AGN). We report observations carried out with the Max Planck Millimetre Bolometer (MAMBO) array at the IRAM 30-m antenna on Pico Veleta of a candidate protocluster with five optically obscured sources selected from the 24-μm Spitzer sample of the First-Look Survey. Interestingly, these sources appear to lie on a high-density filament aligned with the two radio jets of an AGN. Four out of five of the observed sources were detected. We combine these measurements with optical, infrared and radio observations to probe the nature of the candidate protocluster members. Our preliminary conclusions can be summarized as follows: the spectral energy distributions (SEDs) of all sources include both AGN and starburst contributions; the AGN contribution to the bolometric luminosities ranges between 14 and 26 per cent of the total. Such a contribution is enough for the AGN to dominate the emission at 5.8, 8 and 24μm, while the stellar component, inferred from SED fitting, prevails at 1.25mm and at λ < 4.5μm. The present analysis suggests a coherent interplay at high z between extended radio activity and the development of filamentary large-scale structures.

  9. Obscured accretion from AGN surveys

    NASA Astrophysics Data System (ADS)

    Vignali, Cristian

    2014-07-01

    Recent models of super-massive black hole (SMBH) and host galaxy joint evolution predict the presence of a key phase where accretion, traced by obscured Active Galactic Nuclei (AGN) emission, is coupled with powerful star formation. Then feedback processes likely self-regulate the SMBH growth and quench the star-formation activity. AGN in this important evolutionary phase have been revealed in the last decade via surveys at different wavelengths. On the one hand, moderate-to-deep X-ray surveys have allowed a systematic search for heavily obscured AGN, up to very high redshifts (z~5). On the other hand, infrared/optical surveys have been invaluable in offering complementary methods to select obscured AGN also in cases where the nuclear X-ray emission below 10 keV is largely hidden to our view. In this review I will present my personal perspective of the field of obscured accretion from AGN surveys.

  10. X-ray View of Four High-Luminosity Swift-BAT AGN: Unveiling Obscuration and Reflection with Suzaku

    NASA Technical Reports Server (NTRS)

    Fiorettil, V.; Angelini, L.; Mushotzky, R. F.; Koss, M.; Malaguti, G.

    2013-01-01

    Aims. A complete census of obscured Active Galactic Nuclei (AGN) is necessary to reveal the history of the super massive black hole (SMBH) growth and galaxy evolution in the Universe given the complex feedback processes and the fact that much of this growth occurs in an obscured phase. In this context, hard X-ray surveys and dedicated follow-up observations represent a unique tool for selecting highly absorbed AGN and for characterizing the obscuring matter surrounding the SMBH. Here we focus on the absorption and reflection occurring in highly luminous, quasar-like AGN, to study the relation between the geometry of the absorbing matter and the AGN nature (e.g. X-ray, optical, and radio properties), and to help to determine the column density dependency on the AGN luminosity. Methods. The Swift/BAT nine-month survey observed 153 AGN, all with ultra-hard X-ray BAT fluxes in excess of 10(exp -11) erg per square centimeter and an average redshift of 0.03. Among them, four of the most luminous BAT AGN (44.73 less than LogLBAT less than 45.31) were selected as targets of Suzaku follow-up observations: J2246.0+3941 (3C 452), J0407.4+0339 (3C 105), J0318.7+6828, and J0918.5+0425. The column density, scattered/reflected emission, the properties of the Fe K line, and a possible variability are fully analyzed. For the latter, the spectral properties from Chandra, XMM-Newton and Swift/XRT public observations were compared with the present Suzaku analysis, adding an original spectral analysis when non was available from the literature. Results. Of our sample, 3C 452 is the only certain Compton-thick AGN candidate because of i) the high absorption (N(sub H) approximately 4 × 10(exp 23) per square centimeter) and strong Compton reflection; ii) the lack of variability; iii) the "buried" nature, i.e. the low scattering fraction (less than 0.5%) and the extremely low relative [OIII] luminosity. In contrast 3C 105 is not reflection-dominated, despite the comparable column density

  11. Dust Formation, Evolution, and Obscuration Effects in the Very High-Redshift Universe

    NASA Technical Reports Server (NTRS)

    Dwek, Eli; Staguhn, Johannes; Arendt, Richard G.; Kovacs, Attila; Su, Ting; Benford, Dominic J.

    2014-01-01

    The evolution of dust at redshifts z > or approx. 9, and consequently the dust properties, differs greatly from that in the local universe. In contrast to the local universe, core collapse supernovae (CCSNe) are the only source of thermally-condensed dust. Because of the low initial dust-to-gas mass ratio, grain destruction rates are low, so that CCSNe are net producers of interstellar dust. Galaxies with large initial gas mass or high mass infall rate will therefore have a more rapid net rate of dust production comported to galaxies with lower gas mass, even at the same star formation rate. The dust composition is dominated by silicates, which exhibit a strong rise in the UV opacity near the Lyman break. This "silicate-UV break" may be confused with the Lyman break, resulting in a misidentification of a galaxies' photometric redshift. In this paper we demonstrate these effects by analyzing the spectral energy distribution (SED) of MACS1149-JD, a lensed galaxy at z = 9.6. A potential 2mm counterpart of MACS1149-JD has been identified with GISMO. While additional observations are required to corroborate this identification, we use this possible association to illustrate the physical processes and the observational effects of dust in the very high redshift universe. Subject headings: galaxies: high-redshift - galaxies: evolution - galaxies: individual (MACS1149- JD) - Interstellar medium (ISM), nebulae: dust, extinction - physical data and processes: nuclear reactions, nucleosynthesis, abundances.

  12. HIGH-REDSHIFT DUST OBSCURED GALAXIES: A MORPHOLOGY-SPECTRAL ENERGY DISTRIBUTION CONNECTION REVEALED BY KECK ADAPTIVE OPTICS

    SciTech Connect

    Melbourne, J.; Matthews, K.; Soifer, B. T. E-mail: bts@submm.caltech.edu

    2009-06-15

    A simple optical to mid-IR color selection, R - [24]>14, i.e., f {sub {nu}}(24 {mu}m)/f {sub {nu}}(R) {approx}> 1000, identifies highly dust obscured galaxies (DOGs) with typical redshifts of z {approx} 2 {+-} 0.5. Extreme mid-IR luminosities (L {sub IR} > 10{sup 12-14}) suggest that DOGs are powered by a combination of active galactic nuclei (AGNs) and star formation, possibly driven by mergers. In an effort to compare their photometric properties with their rest-frame optical morphologies, we obtained high-spatial resolution (0.''05-0.''1) Keck Adaptive Optics K'-band images of 15 DOGs. The images reveal a wide range of morphologies, including small exponential disks (eight of 15), small ellipticals (four of 15), and unresolved sources (two of 15). One particularly diffuse source could not be classified because of low signal-to-noise ratio. We find a statistically significant correlation between galaxy concentration and mid-IR luminosity, with the most luminous DOGs exhibiting higher concentration and smaller physical size. DOGs with high concentration also tend to have spectral energy distributions (SEDs) suggestive of AGN activity. Thus, central AGN light may be biasing the morphologies of the more luminous DOGs to higher concentration. Conversely, more diffuse DOGs tend to show an SED shape suggestive of star formation. Two of 15 in the sample show multiple resolved components with separations of {approx}1 kpc, circumstantial evidence for ongoing mergers.

  13. DUST FORMATION, EVOLUTION, AND OBSCURATION EFFECTS IN THE VERY HIGH-REDSHIFT UNIVERSE

    SciTech Connect

    Dwek, Eli; Benford, Dominic J.; Staguhn, Johannes; Su, Ting; Arendt, Richard G.; Kovacks, Attila

    2014-06-20

    The evolution of dust at redshifts z ≳ 9, and consequently the dust properties, differs greatly from that in the local universe. In contrast to the local universe, core collapse supernovae (CCSNe) are the only source of thermally condensed dust. Because of the low initial dust-to-gas mass ratio, grain destruction rates are low, so that CCSNe are net producers of interstellar dust. Galaxies with large initial gas mass or high mass infall rate will therefore have a more rapid net rate of dust production compared to galaxies with lower gas mass, even at the same star formation rate. The dust composition is dominated by silicates, which exhibit a strong rise in the UV opacity near the Lyman break. This ''silicate-UV break'' may be confused with the Lyman break, resulting in a misidentification of a galaxy's photometric redshift. In this Letter we demonstrate these effects by analyzing the spectral energy distribution of MACS1149-JD, a lensed galaxy at z = 9.6. A potential 2 mm counterpart of MACS1149-JD has been identified with GISMO. While additional observations are required to corroborate this identification, we use this possible association to illustrate the physical processes and the observational effects of dust in the very high-redshift universe.

  14. Dust Formation, Evolution, and Obscuration Effects in the Very High-Redshift Universe

    NASA Technical Reports Server (NTRS)

    Dwek, Eli; Staguhn, Johannes; Arendt, Richard G.; Kovacks, Attila; Su, Ting; Benford, Dominic J.

    2014-01-01

    The evolution of dust at redshifts z > or approx. 9, and consequently the dust properties, differs greatly from that in the local universe. In contrast to the local universe, core collapse supernovae (CCSNe) are the only source of thermally-condensed dust. Because of the low initial dust-togas mass ratio, grain destruction rates are low, so that CCSNe are net producers of interstellar dust. Galaxies with large initial gas mass or high mass infall rate will therefore have a more rapid net rate of dust production comported to galaxies with lower gas mass, even at the same star formation rate. The dust composition is dominated by silicates, which exhibit a strong rise in the UV opacity near the Lyman break. This "silicate-UV break" may be confused with the Lyman break, resulting in a misidentification of a galaxies' photometric redshift. In this paper we demonstrate these effects by analyzing the spectral energy distribution (SED) of MACS1149-JD, a lensed galaxy at z = 9.6. A potential 2mm counterpart of MACS1149-JD has been identified with GISMO. While additional observations are required to corroborate this identification, we use this possible association to illustrate the physical processes and the observational effects of dust in the very high redshift universe.

  15. Demonstration of high contrast with an obscured aperture with the WFIRST-AFTA shaped pupil coronagraph

    NASA Astrophysics Data System (ADS)

    Cady, Eric; Prada, Camilo Mejia; An, Xin; Balasubramanian, Kunjithapatham; Diaz, Rosemary; Kasdin, N. Jeremy; Kern, Brian; Kuhnert, Andreas; Nemati, Bijan; Poberezhskiy, Ilya; Eldorado Riggs, A. J.; Zimmer, Robert; Zimmerman, Neil

    2016-01-01

    The coronagraph instrument on the Wide-Field Infrared Survey Telescope-Astrophysics-Focused Telescope Asset (WFIRST-AFTA) mission study has two coronagraphic architectures, shaped pupil and hybrid Lyot, which may be interchanged for use in different observing scenarios. Each architecture relies on newly developed mask components to function in the presence of the AFTA aperture, and so both must be matured to a high technology readiness level in advance of the mission. A series of milestones were set to track the development of the technologies required for the instrument; we report on completion of WFIRST-AFTA coronagraph milestone 2-a narrowband 10-8 contrast test with static aberrations for the shaped pupil-and the plans for the upcoming broadband coronagraph milestone 5.

  16. Pursuit tracks chase: exploring the role of eye movements in the detection of chasing

    PubMed Central

    Träuble, Birgit

    2015-01-01

    We explore the role of eye movements in a chase detection task. Unlike the previous studies, which focused on overall performance as indicated by response speed and chase detection accuracy, we decompose the search process into gaze events such as smooth eye movements and use a data-driven approach to separately describe these gaze events. We measured eye movements of four human subjects engaged in a chase detection task displayed on a computer screen. The subjects were asked to detect two chasing rings among twelve other randomly moving rings. Using principal component analysis and support vector machines, we looked at the template and classification images that describe various stages of the detection process. We showed that the subjects mostly search for pairs of rings that move one after another in the same direction with a distance of 3.5–3.8 degrees. To find such pairs, the subjects first looked for regions with a high ring density and then pursued the rings in this region. Most of these groups consisted of two rings. Three subjects preferred to pursue the pair as a single object, while the remaining subject pursued the group by alternating the gaze between the two individual rings. In the discussion, we argue that subjects do not compare the movement of the pursued pair to a singular preformed template that describes a chasing motion. Rather, subjects bring certain hypotheses about what motion may qualify as chase and then, through feedback, they learn to look for a motion pattern that maximizes their performance. PMID:26401454

  17. REVEALING THE HEAVILY OBSCURED ACTIVE GALACTIC NUCLEUS POPULATION OF HIGH-REDSHIFT 3CRR SOURCES WITH CHANDRA X-RAY OBSERVATIONS

    SciTech Connect

    Wilkes, Belinda J.; Kuraszkiewicz, Joanna; Willner, S. P.; Ashby, M. L. N.; Fazio, G. G.; Haas, Martin; Chini, Rolf; Barthel, Peter; Leipski, Christian; Worrall, D. M.; Birkinshaw, Mark; Antonucci, Robert; Lawrence, Charles; Ogle, Patrick; Schulz, Bernhard

    2013-08-10

    Chandra observations of a complete, flux-limited sample of 38 high-redshift (1 < z < 2), low-frequency-selected (and so unbiased in orientation) 3CRR radio sources are reported. The sample includes 21 quasars (=broad-line radio galaxies) and 17 narrow-line radio galaxies (NLRGs) with matched 178 MHz radio luminosity (log L{sub R}(5 GHz) {approx}44-45). The quasars have high radio core fraction, high X-ray luminosities (log L{sub X} {approx}45-46), and soft X-ray hardness ratios (HR {approx}-0.5) indicating low obscuration. The NLRGs have lower core fraction, lower apparent X-ray luminosities (log L{sub X} {approx}43-45), and mostly hard X-ray hardness ratios (HR >0) indicating obscuration (N{sub H} {approx}10{sup 22}-10{sup 24} cm{sup -2}). These properties and the correlation between obscuration and radio core fraction are consistent with orientation-dependent obscuration as in unification models. About half the NLRGs have soft X-ray hardness ratios and/or a high [O III] emission line to X-ray luminosity ratio suggesting obscuration by Compton thick (CT) material so that scattered nuclear or extended X-ray emission dominates (as in NGC 1068). The ratios of unobscured to Compton-thin (10{sup 22} cm{sup -2} < N{sub H}(int) <1.5 Multiplication-Sign 10{sup 24} cm{sup -2}) to CT (N{sub H}(int) >1.5 Multiplication-Sign 10{sup 24} cm{sup -2}) is 2.5:1.4:1 in this high-luminosity, radio-selected sample. The obscured fraction is 0.5, higher than is typically reported for active galactic nuclei at comparable luminosities from multi-wavelength surveys (0.1-0.3). Assuming random nuclear orientation, the unobscured half-opening angle of the disk/wind/torus structure is {approx}60 Degree-Sign and the obscuring material covers 30 Degree-Sign , {approx}12 Degree-Sign of which is CT. The multi-wavelength properties reveal that many NLRGs have intrinsic absorption 10-1000 Multiplication-Sign higher than indicated by their X-ray hardness ratios, and their true L{sub X} values are

  18. The Environments of Obscured Quasars

    NASA Astrophysics Data System (ADS)

    Jones, Kristen M.; Lacy, Mark; Nielsen, Danielle

    2016-01-01

    Supermassive Black Hole (SMBH) feedback is prescribed for driving the high-end shape of the galaxy luminosity function, clearing the circumnuclear environment during the end stages of mergers, and eventually turning off its own accretion. Yet the dominant processes and characteristics of active galactic nuclei are indistinct. Chief among this confusion is how significant the role of dust is in each galaxy. Orientation of the dusty torus is attributed to causing the differences between Sy1 and Sy2, but whether obscured quasars are found in particularly dusty host galaxies, if they exist at a different stage in the merger process (early on, before the dust is blown out), or if they are merely oriented differently than optical quasars is not yet so well distinguished. With obscured quasars now observed to make up 50% or greater of the population of quasars, the question of what causes obscuration becomes vital to address. With this in mind, I study matched samples of obscured and unobscured quasars to characterize their environments, with the intent of addressing what contribution environment has to obscuration levels. I investigate the megaparsec-scale environments of SIRTF Wide-field Infra-Red Extragalactic Survey (SWIRE) quasars at z ˜ 1-3 by cross-correlating the sample with 3.8 million galaxies from the Spitzer Extragalactic Representative Volume Survey (SERVS). Optically obscured quasars are compared to a control sample of optically-bright quasars via selection in the mid-infrared. Environments were observed at 3.6 and 4.5 μm to a depth of ≈ 2 μJy (AB = 23.1). Recent work has found diverse results in such studies, with dependence of environmental richness on both redshift and level of obscuration. I find that, within reasonable error, on average there is no distinct difference between the level of clustering for obscured and normal quasars, and that there is no dependence on redshift of this result within the range of 1.3 < z < 2.5. I compare our results

  19. Obscured Star-Formation in Merging Galaxies: High Resolution Radio Imaging of a Time-Ordered Sequence

    NASA Technical Reports Server (NTRS)

    Neff, S. G.; Campion, S. D.; Ulvestad, J. S.

    2003-01-01

    We present new, deep, high resolution 6cm and 4cm radio continuum images of the central regions of a time-ordered sequence of seven large galaxy mergers. The radio observations are able to detect star-forming re- gions that are completely obscured at optical wavelengths. In all systems, we detect numerous compact radio sources embedded in more diffuse ra- dio emission, with limiting luminosities of approx. 1-5 x 10(exp l8) W Hz or approx. 1-5 times the luminosity of Cas A. Many of the compact radio sources are loosely associated with active starforming regions but not with specific optical or W emission sources. Several of the compact radio sources are coincident with Ultra-luminous X-ray objects (ULX's). In most systems, we are able to measure reliable spectral indices for the stronger sources. We find that the fraction of compact radio cources with nominally flat radio spectral indices (indicating they ae dominated by thermal radio emission from HII regions) decreases with merger age, while the fraction of sources with nonimally steep spectral indices (indicating they are dominated by nonthermal emission from supernova remnants) increases. For the flat-spectrum sources, we estimate the numbers of young massive stars, associated ionized gas masses, we estimate supernova rates and required star-formation rates, We compare these results with those from other well-studied merging galaxy systems and from other determinations of star-formation rates. We gratefully acknowledge use of the NRAO Very Large Array (VLA) and the VLA Archive. NRAO is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

  20. Star formation and obscuration in AGN: A sub-mm study of high-redshift mid-IR selected type-2 QSOs

    NASA Astrophysics Data System (ADS)

    Violino, Giulio; Stevens, Jason; Coppin, Kristen; Geach, James

    2016-08-01

    The AGN unification model describes unobscured and obscured AGN (AGN1 and AGN2) as identical sources, with their different observed properties explained solely by orientation effects; as a result, it predicts no difference in the host galaxies. As an alternative, a second scenario has been proposed in which type-2 AGN represent an earlier stage in the life of AGN characterized by dust-enshrouded host galaxies which contribute to the obscuration and higher star formation activity, at least at earlier epochs. To test this scenario we employ Herschel data at three different wavelengths (250, 350, 500 um) to study the far-IR-to-submm properties of a sample of mid-IR selected type 2 QSOs at high redshift (1.5obscuration of the nucleus (perhaps via a merger) since our AGN1 have systematically lower radio luminosities than our AGN2.

  1. Chasing the High School Graduation Rate: Getting the Data We Need and Using It Right. Policy Information Perspective

    ERIC Educational Resources Information Center

    Barton, Paul E.

    2009-01-01

    This Policy Information Perspective provides a status report on efforts to measure the high school graduation rate more accurately and use it more constructively. The first section of the report discusses obtaining reliable national survey data on the graduation status of young adults and of the population as a whole. The second section makes the…

  2. COMOVING SPACE DENSITY AND OBSCURED FRACTION OF HIGH-REDSHIFT ACTIVE GALACTIC NUCLEI IN THE SUBARU/XMM-NEWTON DEEP SURVEY

    SciTech Connect

    Hiroi, Kazuo; Ueda, Yoshihiro; Akiyama, Masayuki; Watson, Mike G.

    2012-10-10

    We study the comoving space density of X-ray-selected luminous active galactic nuclei (AGNs) and the obscured AGN fraction at high redshifts (3 < z < 5) in the Subaru/XMM-Newton Deep Survey field. From an X-ray source catalog with high completeness of optical identification thanks to deep optical images, we select a sample of 30 AGNs at z > 3 with intrinsic (de-absorbed and rest-frame 2-10 keV) luminosities of L{sub X} = 10{sup 44-45} erg s{sup -1} detected in the 0.5-2 keV band, consisting of 20 and 10 objects with spectroscopic and photometric redshifts, respectively. Utilizing the 1/V{sub max} method, we confirm that the comoving space density of luminous AGNs decreases with redshift above z > 3. When combined with the Chandra-COSMOS result of Civano et al., the density decline of AGNs with L{sub X} = 10{sup 44-45} erg s{sup -1} is well represented by a power law of (1 + z){sup -6.2{+-}0.9}. We also determine the fraction of X-ray obscured AGNs with N{sub H} > 10{sup 22} cm{sup -2} in the Compton-thin population to be 0.54{sup +0.17}{sub -0.19}, by carefully taking into account observational biases including the effects of photon statistics for each source. This result is consistent with an independent determination of the type-2 AGN fraction based on optical properties, for which the fraction is found to be 0.59 {+-} 0.09. Comparing our result with that obtained in the local universe, we conclude that the obscured fraction of luminous AGNs increases significantly from z = 0 to z > 3 by a factor of 2.5 {+-} 1.1.

  3. On the origin of soft X-rays in obscured AGN: answers from high-resolution spectroscopy with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Guainazzi, Matteo; Bianchi, Stefano

    2007-02-01

    We present results of a high-resolution soft X-ray (0.2-2 keV) spectroscopic study of a sample of 69 nearby obscured active galactic nuclei (AGNs) observed with the reflection grating spectrometer (RGS) onboard XMM-Newton. This is the largest sample ever studied with this technique so far. The main conclusions of our study can be summarized as follows: (i) narrow radiative recombination continua are detected in about 36 per cent of the objects in our sample (in 26 per cent their intrinsic width is <=10 eV); (ii) higher order transitions are generally enhanced with respect to pure photoionization, indicating that resonant scattering plays an important role in the ionization/excitation balance. These results support the scenario, whereby the active nucleus is responsible for the X-ray `soft excess' almost ubiquitously observed in nearby obscured AGNs via photoionization of circumnuclear gas. They confirm on a statistical basis the conclusions drawn from the detailed study of the brightest spectra in the sample. Furthermore, we propose a criterion to statistically discriminate between AGN-photoionized sources and starburst galaxies, based on intensity of the forbidden component of the OVII Heα triplet (once normalized to the OVIII Lyα) coupled with the integrated luminosity in He- and H-like oxygen lines.

  4. The Car Chase.

    ERIC Educational Resources Information Center

    Van Dyke, Phylis

    1989-01-01

    Unmotivated and/or slow learning high-school students learned to effectively use consumer information sources by writing reports that justified the hypothetical purchase of a particular automobile. Presented are procedures for setting up the project, a timeline/lesson plan for the unit, grading system, and outcomes. (JDD)

  5. A Blast To Chase

    NASA Astrophysics Data System (ADS)

    2006-02-01

    , this is one of the most prolific galaxies as far as supernovae are concerned. Since 1900, four others have been discovered in it: SN 1901B, SN 1914A, SN 1959E, and SN 1979C. Recent observations with ESA's XMM-Newton space observatory have shown quite surprisingly that SN 1979C is still as bright in X-ray light as it was 25 years ago. In visible light, however, SN 1979C has since then faded by a factor 250. SN 1979C belongs to the class of Type II supernovae and is the result of the explosion of a star that was 18 times more massive than our Sun. High resolution images and their captions are available on this page.

  6. Loss-Chasing, Alexithymia, and Impulsivity in a Gambling Task: Alexithymia as a Precursor to Loss-Chasing Behavior When Gambling

    PubMed Central

    Bibby, Peter A.

    2016-01-01

    Objective: To examine the relationship between loss-chasing, the propensity to continue gambling to recover from losses, alexithymia, a personality trait associated poor emotional processing and impulsivity, the tendency to act quickly without reflection or consideration of the consequences. Method: Two experiments are reported (E1: N = 60, Males, 11; Age, 21.6 years. E2: N = 49, Males, 22; Age, 21.1 years). In experiment 1, two groups (low alexithymia, high alexithymia) completed the Cambridge Gambling Task (CGT). Loss-chasing behavior was investigated. In experiment 2, both alexithymia (low, high) and impulsivity (low, high) were examined also using the CGT. A further change was the order of bet proportion from ascending to descending. Results: Experiment 1 shows loss-chasing behavior in participants high in alexithymia but not those low in alexithymia (ηp2=0.09). Experiment 2 shows loss-chasing behavior in participants both low and high in alexithymia but it was greater for participants high in alexithymia (ηp2 = 0.09). The effect of impulsivity was not statistically significant (ηp2 = 0.01). Loss-chasing behavior was correlated with the emotional facets of alexithymia but not the cognitive facet. Conclusions: Alexithymia is a precursor to loss-chasing when gambling and loss-chasing reflects the cognitive and emotional aspects of gambling. Specifically, the tendency to loss-chase depends on the need to recoup previous losses and failure to process the emotional consequences of those losses. PMID:26834676

  7. The Kiloparsec-scale Star Formation Law at Redshift 4: Widespread, Highly Efficient Star Formation in the Dust-obscured Starburst Galaxy GN20

    NASA Astrophysics Data System (ADS)

    Hodge, J. A.; Riechers, D.; Decarli, R.; Walter, F.; Carilli, C. L.; Daddi, E.; Dannerbauer, H.

    2015-01-01

    We present high-resolution observations of the 880 μm (rest-frame FIR) continuum emission in the z = 4.05 submillimeter galaxy GN20 from the IRAM Plateau de Bure Interferometer (PdBI). These data resolve the obscured star formation (SF) in this unlensed galaxy on scales of 0.''3 × 0.''2 (~2.1 × 1.3 kpc). The observations reveal a bright (16 ± 1 mJy) dusty starburst centered on the cold molecular gas reservoir and showing a bar-like extension along the major axis. The striking anti-correlation with the Hubble Space Telescope/Wide Field Camera 3 imaging suggests that the copious dust surrounding the starburst heavily obscures the rest-frame UV/optical emission. A comparison with 1.2 mm PdBI continuum data reveals no evidence for variations in the dust properties across the source within the uncertainties, consistent with extended SF, and the peak star formation rate surface density (119 ± 8 M ⊙ yr-1 kpc-2) implies that the SF in GN20 remains sub-Eddington on scales down to 3 kpc2. We find that the SF efficiency (SFE) is highest in the central regions of GN20, leading to a resolved SF law with a power-law slope of ΣSFR ~ Σ _H_2^2.1+/- 1.0, and that GN20 lies above the sequence of normal star-forming disks, implying that the dispersion in the SF law is not due solely to morphology or choice of conversion factor. These data extend previous evidence for a fixed SFE per free-fall time to include the star-forming medium on ~kiloparsec scales in a galaxy 12 Gyr ago. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  8. The Evolution of Obscuration in AGN

    NASA Astrophysics Data System (ADS)

    Treister, Ezequiel; Urry, M.; Virani, S.

    2006-09-01

    One fundamental ingredient in our understanding of the AGN population is the ratio of obscured to unobscured AGN and whether this ratio depends on other parameters like intrinsic luminosity or redshift. Observationally, deep X-ray surveys found that the obscured AGN fraction depends on luminosity. However, the dependence on redshift is less clear. In this work, we constructed the largest sample to date of AGN selected in hard X-rays, containing a total of 1229 sources, 631 of them obscured, with a high spectroscopic completeness in order to study the possible dependence of the fraction of obscured sources with redshift and/or luminosity. We confirm that this fraction decreases with increasing luminosity as previously reported and found that at the same time it increases with increasing redshift. This is the first time that this evolution is significantly detected using only optical spectroscopy to separate obscured and unobscured AGN. Additionally, we use the spectral shape and intensity of the X-ray background as a separate constraint on the evolution of the obscured AGN fraction finding consistent results. This result can be interpreted as an evolution in the location of the obscuration, from the central parsec-scale region (the torus) at low redshift to kiloparsec scales (the host galaxy) at high redshift, as it is known that most galaxies contained more dust in the past. Using these results, we calculate the integrated bolometric AGN emission finding it to be at most 5% of the total extragalactic light. Hence, while AGN contribute most of the light at X-ray wavelengths, they constitute only a small fraction of the integrated extragalactic light. We thank the support of the Centro de Astrof\\'{\\i}sica FONDAP and from NASA/{\\it INTEGRAL} grant NNG05GM79G.

  9. Dust Obscuration and Metallicity at High Redshift: New Inferences from UV, Hα, and 8 μm Observations of z ~ 2 Star-forming Galaxies

    NASA Astrophysics Data System (ADS)

    Reddy, Naveen A.; Erb, Dawn K.; Pettini, Max; Steidel, Charles C.; Shapley, Alice E.

    2010-04-01

    We use a sample of 90 spectroscopically confirmed Lyman break galaxies with Hα measurements and Spitzer MIPS 24 μm observations to constrain the relationship between rest-frame 8 μm luminosity (L 8) and star formation rate (SFR) for L* galaxies at z ~ 2. We find a tight correlation with 0.24 dex scatter between L 8 and Hα luminosity/SFR for z ~ 2 galaxies with 1010 L sun <~ L IR <~ 1012 L sun. Employing this relationship with a larger sample of 392 galaxies with spectroscopic redshifts, we find that the UV slope β can be used to recover the dust attenuation of the vast majority of moderately luminous L* galaxies at z ~ 2 to within a 0.4 dex scatter using the local correlation. Separately, young galaxies with ages lsim100 Myr appear to be less dusty than their UV slopes would imply based on the local trend and may follow an extinction curve that is steeper than what is typically assumed. Consequently, very young galaxies at high redshift may be significantly less dusty than inferred previously. Our results provide the first direct evidence, independent of the UV slope, for a correlation between UV and bolometric luminosity (L bol) at high redshift, in the sense that UV-faint galaxies are on average less infrared and less bolometrically luminous than their UV-bright counterparts. The L bol-L UV relation indicates that as the SFR increases, L UV turns over (or "saturates") around the value of L* at z ~ 2, implying that dust obscuration may be largely responsible for modulating the bright end of the UV luminosity function. Finally, dust attenuation is found to correlate with oxygen abundance at z ~ 2. Accounting for systematic differences in local and high-redshift metallicity calibrations, we find that L* galaxies at z ~ 2, while at least an order of magnitude more bolometrically luminous, exhibit ratios of metals to dust that are similar to those of local starbursts. This result is expected if high-redshift galaxies are forming their stars in a less metal

  10. Discovery of an Obscured Broad-Line Region in the High-Redshift Radio Galaxy MRC 2025-218.

    PubMed

    Larkin; McLean; Graham; Becklin; Figer; Gilbert; Levenson; Teplitz; Wilcox; Glassman

    2000-04-10

    This Letter presents infrared spectra taken with the newly commissioned near-infrared spectrometer (NIRSPEC) on the Keck II telescope of the high-redshift radio galaxy MRC 2025-218 (z=2.63). These observations represent the deepest infrared spectra of a radio galaxy to date and have allowed for the detection of Hbeta, [O iii] lambdalambda4959, 5007, [O i] lambda6300, Halpha, [N ii] lambdalambda6548, 6583, and [S ii] lambdalambda6716, 6713. The Halpha emission is very broad (FWHM=9300 km s-1) and luminous (2.6x1044 ergs s-1), and it is very comparable to the line widths and strengths of radio-loud quasars at the same redshift. This strongly supports active galactic nucleus unification models linking radio galaxies and quasars, although we discuss some of the outstanding differences. The line [O iii] lambda5007 is extremely strong and has extended emission with large relative velocities toward the nucleus. We also derive that if the extended emission is due to star formation, each knot has a star formation rate comparable to a Lyman-break galaxy at the same redshift.

  11. THE KILOPARSEC-SCALE STAR FORMATION LAW AT REDSHIFT 4: WIDESPREAD, HIGHLY EFFICIENT STAR FORMATION IN THE DUST-OBSCURED STARBURST GALAXY GN20

    SciTech Connect

    Hodge, J. A.; Riechers, D.; Decarli, R.; Walter, F.; Carilli, C. L.; Daddi, E.

    2015-01-01

    We present high-resolution observations of the 880 μm (rest-frame FIR) continuum emission in the z = 4.05 submillimeter galaxy GN20 from the IRAM Plateau de Bure Interferometer (PdBI). These data resolve the obscured star formation (SF) in this unlensed galaxy on scales of 0.''3 × 0.''2 (∼2.1 × 1.3 kpc). The observations reveal a bright (16 ± 1 mJy) dusty starburst centered on the cold molecular gas reservoir and showing a bar-like extension along the major axis. The striking anti-correlation with the Hubble Space Telescope/Wide Field Camera 3 imaging suggests that the copious dust surrounding the starburst heavily obscures the rest-frame UV/optical emission. A comparison with 1.2 mm PdBI continuum data reveals no evidence for variations in the dust properties across the source within the uncertainties, consistent with extended SF, and the peak star formation rate surface density (119 ± 8 M {sub ☉} yr{sup –1} kpc{sup –2}) implies that the SF in GN20 remains sub-Eddington on scales down to 3 kpc{sup 2}. We find that the SF efficiency (SFE) is highest in the central regions of GN20, leading to a resolved SF law with a power-law slope of Σ{sub SFR} ∼ Σ{sub H{sub 2}{sup 2.1±1.0}}, and that GN20 lies above the sequence of normal star-forming disks, implying that the dispersion in the SF law is not due solely to morphology or choice of conversion factor. These data extend previous evidence for a fixed SFE per free-fall time to include the star-forming medium on ∼kiloparsec scales in a galaxy 12 Gyr ago.

  12. BLACK HOLE GROWTH AND ACTIVE GALACTIC NUCLEI OBSCURATION BY INSTABILITY-DRIVEN INFLOWS IN HIGH-REDSHIFT DISK GALAXIES FED BY COLD STREAMS

    SciTech Connect

    Bournaud, Frederic; Teyssier, Romain; Daddi, Emanuele; Dekel, Avishai; Cacciato, Marcello; Juneau, Stephanie; Shankar, Francesco E-mail: dekel@phys.huji.ac.il

    2011-11-10

    Disk galaxies at high redshift have been predicted to maintain high gas surface densities due to continuous feeding by intense cold streams leading to violent gravitational instability, transient features, and giant clumps. Gravitational torques between the perturbations drive angular momentum out and mass in, and the inflow provides the energy for keeping strong turbulence. We use analytic estimates of the inflow for a self-regulated unstable disk at a Toomre stability parameter Q {approx} 1, and isolated galaxy simulations capable of resolving the nuclear inflow down to the central parsec. We predict an average inflow rate {approx}10 M{sub Sun} yr{sup -1} through the disk of a 10{sup 11} M{sub Sun} galaxy, with conditions representative of z {approx} 2 stream-fed disks. The inflow rate scales with disk mass and (1 + z){sup 3/2}. It includes clump migration and inflow of the smoother component, valid even if clumps disrupt. This inflow grows the bulge, while only a fraction of {approx}> 10{sup -3} of it needs to accrete onto a central black hole (BH), in order to obey the observed BH-bulge relation. A galaxy of 10{sup 11} M{sub Sun} at z {approx} 2 is expected to host a BH of {approx}10{sup 8} M{sub Sun }, accreting on average with moderate sub-Eddington luminosity L{sub X} {approx} 10{sup 42}-10{sup 43} erg s{sup -1}, accompanied by brighter episodes when dense clumps coalesce. We note that in rare massive galaxies at z {approx} 6, the same process may feed {approx}10{sup 9} M{sub Sun} BH at the Eddington rate. High central gas column densities can severely obscure active galactic nuclei in high-redshift disks, possibly hindering their detection in deep X-ray surveys.

  13. 'Chasing the dragon': new knowledge for an old practice.

    PubMed

    Cordova, Juan P; Balan, Sabish; Romero, Jorge; Korniyenko, Aleksandr; Alviar, Carlos L; Paniz-Mondolfi, Alberto; Jean, Raymonde

    2014-01-01

    Heroin administration by "chasing the dragon," whereby the user places freebase heroin on aluminum foil, heats it below with a flame, and inhales the pyrolysate through a straw, can be associated with the rare development of a delayed-onset spongiform leukoencephalopathy. We report the case of a 46-year-old woman with a psychiatric diagnosis of depression and heroin dependence by "chasing the dragon" admitted with features of altered mental status and later development of catatonia, abulia, and akinetic mutism. A brain magnetic resonance image evidenced bilateral symmetric high-signal lesions in the white matter of the cerebrum and cerebellum on T2-weighted images compatible with toxic leukoencephalopathy. The patient's condition resolved after a hospital stay of 2 months with supportive treatment. Acute onset of neurobehavioral changes, including confusion, apathy, and cerebellar signs in a person with exposure to heroin, should prompt one to consider toxic leukoencephalopathy as a cause of presentation.

  14. HERA: Chasing Our Cosmic Dawn

    NASA Astrophysics Data System (ADS)

    DeBoer, David; Bowman, J. D.; Jacobs, D.; Parsons, A.; Liu, A.; Werthimer, D.; Ali, Z.; Carilli, C. L.; Chiang, C.; Sievers, J. L.; Furlanetto, S. R.; Hewitt, J. N.; Tegmark, M.; Dillon, J. S.; Bradley, R. F.; Moore, D.; Aguirre, J. E.; Bernardi, G.; Walbrugh, W.; Morales, M. F.; Pober, J.

    2014-04-01

    The Hydrogen Epoch of Reionization Arrays (HERA) roadmap is a staged program that uses the unique properties of the 21-cm line from neutral hydrogen to probe the Epoch of Reionization (EoR) and the preceding Dark Ages. During these epochs, roughly 0.3-1 Gyr after the Big Bang, the first stars and black holes heated and reionized the Universe following cosmic recombination. Direct observation of the large scale structure of reionization and its evolution with time will have a profound impact on our understanding of the birth of the first galaxies and black holes, their influence on the intergalactic medium (IGM), and cosmology. Detecting, characterizing and ultimately imaging this epoch is a key goal for the community and was the top priority in the Radio, Millimeter, and Sub-millimeter category of recommended new facilities for mid-scale funding in the most recent decadal survey. Current projects (PAPER, MWA, LOFAR, GMRT) are striving to make the first detection of the statistical power spectrum of the signal, but current best limits still fall above even optimistic predictions of its intrinsic strength. While these projects are still taking data, it is recognized that an optimized array based on our new understanding of the signal characteristics is needed to make a strong detection and begin to characterize this signal over multiple scales and redshifts. The HERA collaboration is chasing this signal by selectively expanding the sensitivity at these frequencies with a new array to be constructed in South Africa, at the current location of PAPER. As the area increases, so do the data and pipeline needs. This paper will outline the telescope and discuss its processing needs.

  15. Chinese Learning Journeys: Chasing the Dream

    ERIC Educational Resources Information Center

    Su, Feng, Ed.

    2011-01-01

    Eight students from mainland China chart their learning journeys across national and continental boundaries and socio-cultural contexts. The five women and three men structure their experiences of studying in China and the West around the turning points and life changing choices they made in chasing their dreams. They embody its emergent…

  16. Does the obscured AGN fraction really depend on luminosity?

    NASA Astrophysics Data System (ADS)

    Sazonov, S.; Churazov, E.; Krivonos, R.

    2015-12-01

    We use a sample of 151 local non-blazar active galactic nuclei (AGN) selected from the INTEGRAL all-sky hard X-ray survey to investigate if the observed declining trend of the fraction of obscured (i.e. showing X-ray absorption) AGN with increasing luminosity is mostly an intrinsic or selection effect. Using a torus-obscuration model, we demonstrate that in addition to negative bias, due to absorption in the torus, in finding obscured AGN in hard X-ray flux-limited surveys, there is also positive bias in finding unobscured AGN, due to Compton reflection in the torus. These biases can be even stronger taking into account plausible intrinsic collimation of hard X-ray emission along the axis of the obscuring torus. Given the AGN luminosity function, which steepens at high luminosities, these observational biases lead to a decreasing observed fraction of obscured AGN with increasing luminosity even if this fraction has no intrinsic luminosity dependence. We find that if the central hard X-ray source in AGN is isotropic, the intrinsic (i.e. corrected for biases) obscured AGN fraction still shows a declining trend with luminosity, although the intrinsic obscured fraction is significantly larger than the observed one: the actual fraction is larger than ˜85 per cent at L ≲ 1042.5 erg s-1 (17-60 keV), and decreases to ≲60 per cent at L ≳ 1044 erg s-1. In terms of the half-opening angle θ of an obscuring torus, this implies that θ ≲ 30° in lower luminosity AGN, and θ ≳ 45° in higher luminosity ones. If, however, the emission from the central supermassive black hole is collimated as dL/dΩ ∝ cos α, the intrinsic dependence of the obscured AGN fraction is consistent with a luminosity-independent torus half-opening angle θ ˜ 30°.

  17. 27 CFR 19.346 - Determining obscuration.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... water may be added to a lot of spirits to be bottled for which the determination of proof obscuration is... chapter, the proof obscuration of spirits to be bottled on the basis of a representative sample taken...

  18. 27 CFR 19.346 - Determining obscuration.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... water may be added to a lot of spirits to be bottled for which the determination of proof obscuration is... chapter, the proof obscuration of spirits to be bottled on the basis of a representative sample taken...

  19. 27 CFR 19.346 - Determining obscuration.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... water may be added to a lot of spirits to be bottled for which the determination of proof obscuration is... chapter, the proof obscuration of spirits to be bottled on the basis of a representative sample taken...

  20. 27 CFR 19.346 - Determining obscuration.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... water may be added to a lot of spirits to be bottled for which the determination of proof obscuration is... chapter, the proof obscuration of spirits to be bottled on the basis of a representative sample taken...

  1. Chasing losses in online poker and casino games: characteristics and game play of Internet gamblers at risk of disordered gambling.

    PubMed

    Gainsbury, Sally M; Suhonen, Niko; Saastamoinen, Jani

    2014-07-30

    Disordered Internet gambling is a psychological disorder that represents an important public health issue due to the increase in highly available and conveniently accessible Internet gambling sites. Chasing losses is one of the few observable markers of at-risk and problem gambling that may be used to detect early signs of disordered Internet gambling. This study examined loss chasing behaviour in a sample of Internet casino and poker players and the socio-demographic variables, irrational beliefs, and gambling behaviours associated with chasing losses. An online survey was completed by 10,838 Internet gamblers (58% male) from 96 countries. The results showed that Internet casino players had a greater tendency to report chasing losses than poker players and gamblers who reported chasing losses were more likely to hold irrational beliefs about gambling and spend more time and money gambling than those who reported that they were unaffected by previous losses. Gamblers who played for excitement and to win money were more likely to report chasing losses. This study is one of the largest ever studies of Internet gamblers and the results are highly significant as they provide insight into the characteristics and behaviours of gamblers using this mode of access.

  2. Chasing losses in online poker and casino games: characteristics and game play of Internet gamblers at risk of disordered gambling.

    PubMed

    Gainsbury, Sally M; Suhonen, Niko; Saastamoinen, Jani

    2014-07-30

    Disordered Internet gambling is a psychological disorder that represents an important public health issue due to the increase in highly available and conveniently accessible Internet gambling sites. Chasing losses is one of the few observable markers of at-risk and problem gambling that may be used to detect early signs of disordered Internet gambling. This study examined loss chasing behaviour in a sample of Internet casino and poker players and the socio-demographic variables, irrational beliefs, and gambling behaviours associated with chasing losses. An online survey was completed by 10,838 Internet gamblers (58% male) from 96 countries. The results showed that Internet casino players had a greater tendency to report chasing losses than poker players and gamblers who reported chasing losses were more likely to hold irrational beliefs about gambling and spend more time and money gambling than those who reported that they were unaffected by previous losses. Gamblers who played for excitement and to win money were more likely to report chasing losses. This study is one of the largest ever studies of Internet gamblers and the results are highly significant as they provide insight into the characteristics and behaviours of gamblers using this mode of access. PMID:24746392

  3. 78 FR 23800 - JPMorgan Chase & Co., et al.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-22

    ... Hambrecht & Quist Employee Venture Fund, L.P. (collectively, the ``Existing Partnerships''); The BSC... Venture Fund, L.P., et al., Investment Company Act Release Nos. 23396 (August 21, 1998) (notice) and 23438... benefit of highly compensated employees of JPMorgan Chase, as part of a program designed to create...

  4. An un-obscured four spherical mirrors based" collimator as a tradeoff solution for the Optical Ground Support Equipment (OGSE) of the High Resolution Camera (HRIC) of Simbio-Sys

    NASA Astrophysics Data System (ADS)

    Barilli, M.; Bartoli, A.; Dami, M.; Flamini, E.; Formaro, R.; Grifoni, F.; Longo, F.; Pompei, C.

    2012-09-01

    The authors present the tradeoff and the merit criteria that lead to the selection of the M. Brunn [1] "un obscured four mirrors based telescope" as the collimator of the Optical Ground Support Equipment in the frame of the Assembly Integration and Verification (AIV) activities forecast for the optical characterization of the High Resolution Camera (HRIC) on board of the Simbio-sys mission to Mercury, instrument currently under development and manufacturing at Selex Galileo (SG) facilities in its Florence site. Several optical configurations have been accounted for the design and manufacturing of the three meters focal length, diffraction limited and wide field of view (0.4X0.6 degs) toolkit. From the classical un obscured systems such as the aspheric solution based onto two hyperbolic mirror, working under an f - number of 13.6, the Brunn solution revealed excellent optical quality free from coma, astigmatism and spherical aberration accomplished by an ultra compact design in within a volume of 1.2x1.0 x0.5 cubic meters and other basic advantages such as the relative easy way in aligning and manufacturing the mirrors.

  5. Single dose testosterone administration reduces loss chasing in healthy females.

    PubMed

    Wu, Yin; Liu, Jinting; Qu, Lujing; Eisenegger, Christoph; Clark, Luke; Zhou, Xiaolin

    2016-09-01

    Testosterone has been linked to modulation of impulsivity and risky choice, potentially mediated by changes in reward or punishment sensitivity. This study investigated the effect of testosterone on risk-taking and the adjustment of risk-taking on trials following a gain or a loss. Loss chasing is operationalized herein as the propensity to recover losses by increasing risky choice. Healthy female participants (n=26) received a single-dose of 0.5mg sublingual testosterone in a double-blind, placebo-controlled crossover design. At 240min post-administration, participants performed a gambling task with a high and a low risk option. In the placebo condition, participants were more likely to choose the high risk option following losses compared to wins. This effect was abolished on the testosterone session. Ignoring prior outcomes, no overall changes in risk-taking were observed. Our data indicate that testosterone affects human decision-making via diminishing sensitivity to punishment. PMID:27236486

  6. NO2 DOAS Measurements of Traffic Emissions by Chasing Cars

    NASA Astrophysics Data System (ADS)

    Zhu, Ying; Lipkowitsch, Ivo; Chan, Ka Lok; Bräu, Melanie; Wenig, Mark

    2016-04-01

    On this poster we present NO2 measurements using a Cavity-Enhanced DOAS on a measurement bus which we used to chase other vehicles to measure their NO2 emissions. Emissions of nitrogen oxides from on-road vehicles have received highly attention recently due to the increasing trend of ambient NOx level. It is particularly important to identify and quantify the direct emission and secondary formation of NO2 contributed by traffic emissions, in order to study the impact to the local air quality. We sampled on-road emissions in different environments and different driving conditions (e.g. urban, highway, different speeds). We analyse the data set in terms of spatial and temporal variability to search for temporal and spatial patterns. We present mean values sorted for different vehicle types, distance to the target car and travelling speeds to provide an emission data base from this measurement study.

  7. Toxic leucoencephalopathy after 'chasing the dragon'.

    PubMed

    Singh, Rajinder; Saini, Monica

    2015-06-01

    Toxic leucoencephalopathy (TLE) is a rare neurological complication of heroin abuse. 'Chasing the dragon' is an inhalational mode of heroin abuse that originated in Southeast Asia. Intriguingly, no cases of TLE have been reported from this region, although the inhalational mode of heroin abuse is common. We herein report the case of a middle-aged man with a history of polysubstance abuse who presented with progressive neurological symptoms and progressed to an uncommunicative state. While the initial impression was that of iatrogenic parkinsonism, diffuse leucoencephalopathy with sparing of the cerebellum was noted on magnetic resonance imaging. In view of his history of inhalational heroin abuse close to the onset of the neurological symptoms, a diagnosis of TLE was made. No clinical improvement was noted with administration of a dopaminergic agent. This is the first known case of delayed TLE following heroin inhalation from Southeast Asia with the unusual feature of cerebellar sparing.

  8. The Chase to Capture Gamma Ray Bursts

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil

    2008-01-01

    Gamma-ray bursts are the most powerful explosions in the universe, thought to be the birth cries of black holes. It has taken 40 years of international cooperation and competition to begin to unravel the mystery of their origin. The most recent chapter in this field is being written by the SWIFT mission, a fast-response satellite with 3 power telescopes. An international team from countries all over the world participates in the chase to capture the fading light of bursts detected by SWIFT. This talk will discuss the challenges and excitement of building this space observatory. New results will be presented on our growing understanding of exploding stars and fiery mergers of orbiting stars.

  9. Sensitive radio survey of obscured quasar candidates

    NASA Astrophysics Data System (ADS)

    Alexandroff, Rachael M.; Zakamska, Nadia L.; van Velzen, Sjoert; Greene, Jenny E.; Strauss, Michael A.

    2016-08-01

    We study the radio properties of moderately obscured quasars in samples at both low (z ˜ 0.5) and high (z ˜ 2.5) redshift to understand the role of radio activity in accretion, using the Karl G. Jansky Very Large Array (VLA) at 6.0GHz and 1.4GHz. Our z ˜ 2.5 sample consists of optically-selected obscured quasar candidates, all of which are radio-quiet, with typical radio luminosities of νLν[1.4 GHz]⪉ 10^{40} erg s-1. Only a single source is individually detected in our deep (rms˜10 μJy) exposures. This population would not be identified by radio-based selection methods used for distinguishing dusty star-forming galaxies and obscured active nuclei. In our pilot A-array study of z ˜ 0.5 radio-quiet quasars, we spatially resolve four of five objects on scales ˜5 kpc and find they have steep spectral indices with an average value of α = -0.75. Therefore, radio emission in these sources could be due to jet-driven or radiatively driven bubbles interacting with interstellar material on the scale of the host galaxy. Finally, we also study the additional population of ˜200 faint (˜40μJy - 40mJy) field radio sources observed over ˜120 arcmin2 of our data. 60% of these detections (excluding our original targets) are matched in the Sloan Digital Sky Survey (SDSS) and/or Wide-Field Infrared Survey Explorer (WISE) and are, in roughly equal shares, active galactic nuclei (AGN) at a broad range of redshifts, passive galaxies with no other signs of nuclear activity and infrared-bright but optically faint sources. Spectroscopically or photometrically confirmed star-forming galaxies constitute only a small minority of the matches. Such sensitive radio surveys allow us to address important questions of AGN evolution and evaluate the AGN contribution to the radio-quiet sky.

  10. Chasing behavior and optomotor following in free-flying male blowflies: flight performance and interactions of the underlying control systems.

    PubMed

    Trischler, Christine; Kern, Roland; Egelhaaf, Martin

    2010-01-01

    The chasing behavior of male blowflies after small targets belongs to the most rapid and virtuosic visually guided behaviors found in nature. Since in a structured environment any turn towards a target inevitably leads to a displacement of the entire retinal image in the opposite direction, it might evoke optomotor following responses counteracting the turn. To analyze potential interactions between the control systems underlying chasing behavior and optomotor following, respectively, we performed behavioral experiments on male blowflies and examined the characteristics of the two flight control systems in isolation and in combination. Three findings are particularly striking. (i) The characteristic saccadic flight and gaze style - a distinctive feature of blowfly cruising flights - is largely abandoned when the entire visual surroundings move around the fly; in this case flies tend to follow the moving pattern in a relatively continuous and smooth way. (ii) When male flies engage in following a small target, they also employ a smooth pursuit strategy. (iii) Although blowflies are reluctant to fly at high background velocities, the performance and dynamical characteristics of the chasing system are not much affected when the background moves in either the same or in the opposite direction as the target. Hence, the optomotor following response is largely suppressed by the chasing system and does not much impair chasing performance.

  11. Handling target obscuration through Markov chain observations

    NASA Astrophysics Data System (ADS)

    Kouritzin, Michael A.; Wu, Biao

    2008-04-01

    Target Obscuration, including foliage or building obscuration of ground targets and landscape or horizon obscuration of airborne targets, plagues many real world filtering problems. In particular, ground moving target identification Doppler radar, mounted on a surveillance aircraft or unattended airborne vehicle, is used to detect motion consistent with targets of interest. However, these targets try to obscure themselves (at least partially) by, for example, traveling along the edge of a forest or around buildings. This has the effect of creating random blockages in the Doppler radar image that move dynamically and somewhat randomly through this image. Herein, we address tracking problems with target obscuration by building memory into the observations, eschewing the usual corrupted, distorted partial measurement assumptions of filtering in favor of dynamic Markov chain assumptions. In particular, we assume the observations are a Markov chain whose transition probabilities depend upon the signal. The state of the observation Markov chain attempts to depict the current obscuration and the Markov chain dynamics are used to handle the evolution of the partially obscured radar image. Modifications of the classical filtering equations that allow observation memory (in the form of a Markov chain) are given. We use particle filters to estimate the position of the moving targets. Moreover, positive proof-of-concept simulations are included.

  12. For College Freshmen, Four-Legged Friends Chase Away Homesickness

    MedlinePlus

    ... College Freshmen, Four-Legged Friends Chase Away Homesickness Dog therapy helps boost students' life satisfaction, researchers say ... buddy, new research suggests. The study found that dog therapy can ease homesickness in first-year college ...

  13. Chasing Mendel: five questions for personalized medicine.

    PubMed

    Joyner, Michael J; Prendergast, Franklyn G

    2014-06-01

    Ideas about personalized medicine are underpinned in part by evolutionary biology's Modern Synthesis. In this essay we link personalized medicine to the efforts of the early statistical investigators who quantified the heritability of human phenotype and then attempted to reconcile their observations with Mendelian genetics. As information about the heritability of common diseases was obtained, similar efforts were directed at understanding the genetic basis of disease phenotypes. These ideas were part of the rationale driving the Human Genome Project and subsequently the personalized medicine movement. In this context, we discuss: (1) the current state of the genotype-phenotype relationship in humans, (2) the common-disease-common-variant hypothesis, (3) the current ability of 'omic' information to inform clinical decision making, (4) emerging ideas about the therapeutic insight available from rare genetic variants, and (5) the social and behavioural barriers to the wider potential success of personalized medicine. There are significant gaps in knowledge as well as conceptual, intellectual, and philosophical limitations in each of these five areas. We then provide specific recommendations to mitigate these limitations and close by asking if it is time for the biomedical research community to 'stop chasing Mendel?'

  14. Flamingos 2 Spectroscopy of Obscured and Unobscured Quasars

    NASA Astrophysics Data System (ADS)

    Ridgway, Susan; Lacy, Mark; Urrutia, Tanya; Petric, Andreea

    2013-08-01

    We will use Flamingos-2 to obtain spectra of luminous AGN and quasars selected in the mid-infrared. Mid-infrared selection is much less biased with respect to obscuration than optical and X-ray techniques, and hence allows for finding obscured (Type-2) quasars as well as Type-1 quasars. Our survey so far has been very successful and has provided an unique opportunity to construct luminosity functions for both Type-1 and Type-2 quasars selected in the same way and covering similar redshifts and luminosities. We have quantifed the change in the obscured fraction with luminosity and redshift for the first time, and find interesting indications that at high redshift the obscured fraction rises, consistent with models for the joint formation of the galaxy and black hole populations. Our samples are, however, still quite incomplete at low fluxes (and therefore lower luminosities at a given redshift), particularly in the southern hemisphere. Near-infrared spectroscopy, such as that we have previously obtained with NIRI at Gemini N, offers us the best possibility of bringing these southern samples to a reasonable completeness level, and will greatly increase the number of high z quasars in our sample. This will allow us to better judge our tantalizing initial results on the redshift evolution of the obscured fraction. In addition, these southern targets can be followed up with ALMA and GEMS/GSAOI to study the morphologies and star-formation properties of the hosts, allowing further exploration of the relationship between the formation of massive bulges and supermassive blackholes in the early universe.

  15. ECMO: Improving our Results by Chasing the Rabbits

    PubMed Central

    Canêo, Luiz Fernando; Neirotti, Rodolfo A.

    2015-01-01

    As Marcelo Giugale published in the Financial Times, Latin America, on the whole, has not excelled at innovation - doing the same things in a new and better way or at doing new things. It has been slow to acquire, adopt and adapt technologies by this time available in other places[1]. Although extracorporeal membrane oxygenation (ECMO) is not a new technology, its use in Latin America is not widespread as needed. Furthermore, we still have a number centers doing ECMO, not reporting their cases, lacking a structured training program and not registered with the extracorporeal life support organization (ELSO). With this scenario, and accepting that ECMO is the first step in any circulatory support program, it is difficult to anticipate the incorporation of new and more complex devices as the technologically advanced world is currently doing. However, the good news is that with the support of experts from USA, Europe and Canada the results in Latin America ELSO'S centers are improving by following its guidelines for training, and using a standard educational process. There is no doubt that we can learn a great deal from the high velocity organizations - the rabbits - whom everyone chases but never catches, that manage to stay ahead because of their endurance, responsiveness, and their velocity in self-correction[2]. PMID:26934407

  16. The CHASE laboratory search for chameleon dark energy

    SciTech Connect

    Steffen, Jason H.; /Fermilab

    2010-11-01

    A scalar field is a favorite candidate for the particle responsible for dark energy. However, few theoretical means exist that can simultaneously explain the observed acceleration of the Universe and evade tests of gravity. The chameleon mechanism, whereby the properties of a particle depend upon the local environment, is one possible avenue. We present the results of the Chameleon Afterglow Search (CHASE) experiment, a laboratory probe for chameleon dark energy. CHASE marks a significant improvement other searches for chameleons both in terms of its sensitivity to the photon/chameleon coupling as well as its sensitivity to the classes of chameleon dark energy models and standard power-law models. Since chameleon dark energy is virtually indistinguishable from a cosmological constant, CHASE tests dark energy models in a manner not accessible to astronomical surveys.

  17. The most obscured AGN in the COSMOS field

    NASA Astrophysics Data System (ADS)

    Lanzuisi, G.; Perna, M.; Delvecchio, I.; Berta, S.; Brusa, M.; Cappelluti, N.; Comastri, A.; Gilli, R.; Gruppioni, C.; Mignoli, M.; Pozzi, F.; Vietri, G.; Vignali, C.; Zamorani, G.

    2015-06-01

    Highly obscured active galactic nuclei (AGN) are common in nearby galaxies, but are difficult to observe beyond the local Universe, where they are expected to significantly contribute to the black hole accretion rate density. Furthermore, Compton-thick (CT) absorbers (NH ≳ 1024 cm-2) suppress even the hard X-ray (2-10 keV) AGN nuclear emission, and therefore the column density distribution above 1024 cm-2 is largely unknown. We present the identification and multi-wavelength properties of a heavily obscured (NH ≳ 1025 cm-2), intrinsically luminous (L2-10 > 1044 erg s-1) AGN at z = 0.353 in the COSMOS field. Several independent indicators, such as the shape of the X-ray spectrum, the decomposition of the spectral energy distribution and X-ray/[NeV] and X-ray/6 μm luminosity ratios, agree on the fact that the nuclear emission must be suppressed by a ≳1025 cm-2 column density. The host galaxy properties show that this highly obscured AGN is hosted in a massive star-forming galaxy, showing a barred morphology, which is known to correlate with the presence of CT absorbers. Finally, asymmetric and blueshifted components in several optical high-ionization emission lines indicate the presence of a galactic outflow, possibly driven by the intense AGN activity (LBol/LEdd = 0.3-0.5). Such highly obscured, highly accreting AGN are intrinsically very rare at low redshift, whereas they are expected to be much more common at the peak of the star formation and BH accretion history, at z ~ 2-3. We demonstrate that a fully multi-wavelength approach can recover a sizable sample of such peculiar sources in large and deep surveys such as COSMOS.

  18. The impact of the dusty torus on obscured quasar halo mass measurements

    NASA Astrophysics Data System (ADS)

    DiPompeo, M. A.; Runnoe, J. C.; Hickox, R. C.; Myers, A. D.; Geach, J. E.

    2016-07-01

    Recent studies have found that obscured quasars cluster more strongly and are thus hosted by dark matter haloes of larger mass than their unobscured counterparts. These results pose a challenge for the simplest unification models, in which obscured objects are intrinsically the same as unobscured sources but seen through a dusty line of sight. There is general consensus that a structure like a `dusty torus' exists, meaning that this intrinsic similarity is likely the case for at least some subset of obscured quasars. However, the larger host halo masses of obscured quasars imply that there is a second obscured population that has an even higher clustering amplitude and typical halo mass. Here, we use simple assumptions about the host halo mass distributions of quasars, along with analytical methods and cosmological N-body simulations to isolate the signal from this population. We provide values for the bias and halo mass as a function of the fraction of the `non-torus-obscured' population. Adopting a reasonable value for this fraction of ˜25 per cent implies a non-torus-obscured-quasar bias that is much higher than the observed obscured quasar bias, because a large fraction of the obscured population shares the same clustering strength as the unobscured objects. For this non-torus-obscured population, we derive a bias of ˜3, and typical halo masses of ˜3 × 1013 M⊙ h-1 at z = 1. These massive haloes are likely the descendants of high-mass unobscured quasars at high redshift, and will evolve into members of galaxy groups at z = 0.

  19. 27 CFR 19.376 - Determining obscuration.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... obsecuration as prescribed in 27 CFR § 30.32 of spirits to be bottled on the basis of a representative sample... degree of the proof at which the spirits will be bottled. Only water may be added to a lot of spirits to be bottled for which the determination of proof obscuration is made from a sample under this...

  20. Giant scattering cones in obscured quasars

    NASA Astrophysics Data System (ADS)

    Obied, Georges; Zakamska, Nadia L.; Wylezalek, Dominika; Liu, Guilin

    2016-03-01

    We analyse Hubble Space Telescope observations of scattering regions in 20 luminous obscured quasars at 0.24 < z < 0.65 (11 new observations and nine archival ones) observed at rest frame ˜3000 Å. We find spectacular 5-10 kpc-scale scattering regions in almost all cases. The median scattering efficiency at this wavelength (the ratio of observed to estimated intrinsic flux) is 2.3, and 73 per cent of the observed flux at this wavelength is due to scattered light, which if unaccounted for may strongly bias estimates of quasar hosts' star formation rates. Modelling these regions as illuminated dusty cones, we estimate the radial density distributions of the interstellar medium as well as the geometric properties of circumnuclear quasar obscuration - inclinations and covering factors. Small derived opening angles (median half-angle and standard deviation 27° ± 9°) are inconsistent with a 1:1 type 1/type 2 ratio. We suggest that quasar obscuration is patchy and that the observer has an ˜40 per cent chance of seeing a type 1 source even through the obscuration. We estimate median density profile of the scattering medium to be nH = 0.04-0.5 (1 kpc/r)2 cm-3, depending on the method. Quasars in our sample likely exhibit galaxy-wide winds, but if these consist of optically thick clouds then only a small fraction of the wind mass ( ≲ 10 per cent) contributes to scattering.

  1. Speech masking and cancelling and voice obscuration

    DOEpatents

    Holzrichter, John F.

    2013-09-10

    A non-acoustic sensor is used to measure a user's speech and then broadcasts an obscuring acoustic signal diminishing the user's vocal acoustic output intensity and/or distorting the voice sounds making them unintelligible to persons nearby. The non-acoustic sensor is positioned proximate or contacting a user's neck or head skin tissue for sensing speech production information.

  2. Calculating Obscuration Ratios Of Contaminated Surfaces

    NASA Technical Reports Server (NTRS)

    Barengoltz, Jack B.

    1989-01-01

    Equations derived to estimate obscuration ratios of surfaces contaminated by particles. Ratio is fraction of surface area covered by particles. Useful as index of cleanliness in clean-room operations in manufacturing of semiconductor devices, magnetic recording media, optical devices, and pharmaceutical and biotechnological products.

  3. 75 FR 31510 - Fox Chase Bancorp, Inc., Hatboro, PA; Approval of Conversion

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-03

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE TREASURY Office of Thrift Supervision Fox Chase Bancorp, Inc., Hatboro, PA; Approval of Conversion Application... Fox Chase MHC and Fox Chase Bank, Hatboro, Pennsylvania, to convert to the stock form of...

  4. Obscurant representation for realistic IR simulation

    NASA Astrophysics Data System (ADS)

    Gozard, Patrick; Le Goff, Alain; Cathala, Thierry; Latger, Jean; Boudet, Antoine

    2003-09-01

    Obscurant representation is a key component of ground battlefield simulation, especially in the infrared domain. Obscurant are special counter measures (clouds) classically used to hide armored vehicles and deceive threatens. Obscurants are very difficult to represent especially because of multi diffusion effects of hot particles and smoke, but this representation is very important to quantify the efficiency of the decoy. This article describes a new model being involved in the simulation workshop CHORALE of the French MoD. The simulation workshop CHORALE developed in collaboration with OKTAL SE company is used by government services and industrial companies for weapon system validation and qualification trials in the infrared domain. The main operational reference for CHORALE is the assessment of the infrared guidance system of the Storm Shadow missile French version, called Scalp. This new model, integrated in CHORALE, enables to simulate the emitted radiance and the transmission of any pre computed obscurant cloud in the virtual battlefield. In the modeling step, the cloud is defined by a set of "voxels" (elementary volume elements). Each voxel contains the spectral extinction coefficient and the spectral scattering coefficients. The shape, i.e. the voxels content, is changing with time to convey the dynamic evolution of the obscurant. In the Non Real Time rendering step, primary rays are traced inside the clouds. For each voxel, scattering rays are then traced to their neighboring voxels and the local hot sources. Actually, ray tracing is used to solve the Radiative Transfer Equation. The main advantage is to be able to solve it taking into account the synthetic environment: the local terrain, the target hidden in the cloud, the atmospheric and weather conditions. The main originality is the multithreading ray tracing which enables to tackle huge quantities of rays in complex geometric environment.

  5. Stuart Chase: At Right Angles to Laissez-faire

    ERIC Educational Resources Information Center

    Saeger, James Schofield

    1972-01-01

    Stuart Chase, through his writings, contributed greatly to acquainting the American public with many concepts generally accepted today: social planning to eliminate economic waste, greater government regulation of business, confrontation of technological unemployment, a national approach to social and economic questions at right angles to laissez…

  6. A compilation of chase work characterizes this image, looking south, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    A compilation of chase work characterizes this image, looking south, in the niche which slightly separates E Building form R Building, on the north side - Department of Energy, Mound Facility, Electronics Laboratory Building (E Building), One Mound Road, Miamisburg, Montgomery County, OH

  7. Heroin smoking by 'chasing the dragon': origins and history.

    PubMed

    Strang, J; Griffiths, P; Gossop, M

    1997-06-01

    The history of heroin smoking and the subsequent development and spread of 'chasing the dragon' are examined. The first heroin smoking originated in Shanghai in the 1920s and involved use of porcelain bowls and bamboo tubes, thereafter spreading across much of Eastern Asia and to the United States over the next decade. 'Chasing the dragon' was a later refinement of this form of heroin smoking, originating in or near Hong Kong in the 1950s, and refers to the ingestion of heroin by inhaling the vapours which result when the drug is heated-typically on tin-foil above a flame. Subsequent spread of 'chasing the dragon' included spread to other parts of South East Asia during the 1960s and 1970s, to some parts of Europe during the late 1970s and early 1980s, and to much of the Indian sub-continent during the 1980s. At the time of writing, 'chasing the dragon' has now been reliably reported from many parts of the world but not from others with an established heroin problem-such as the United States and Australia. The significance of this new form of heroin use is examined, including consideration of the role of the different effect with this new form of use, the different types of heroin, and changing public attitudes to injecting.

  8. Beyond prevention: containment rhetoric in the case of bug chasing.

    PubMed

    Malkowski, Jennifer

    2014-06-01

    Bug chasing, the practice of pursuing HIV positive sexual partners in order to acquire HIV, presents multiple dilemmas for health affiliates in terms of how to address discourses and practices that challenge widely held beliefs about health and medicine. In order to examine how researchers respond to controversial counterpublic rhetorics, this essay chronicles the construction of "bug chasing" in published social science literature. Guided by a theory of containment rhetoric, I analyze how bug chasers are configured in the language of social science used to describe and explain them. I find that social scientific coverage of bug chasing often addresses the behavior using a recipe of rhetorical containment: first, authors gaze upon bug chasers via distanced descriptions of the community; second, authors characterize the behavior as exhibiting an idealistic naiveté; and, third, authors stress the inconceivable, and therefore reproachable, sacrifice that bug chasing ultimately demands of its onlookers and participants. In closing, I evaluate the consequences of this containment rhetoric and offer three rhetorical maneuvers to aid future scholarship that examines the discourses and communities that counter dominant health ideologies. PMID:24682645

  9. From Student to Banker: Observations from the Chase Bank.

    ERIC Educational Resources Information Center

    Burns, Stanley

    The experience of Chase Manhattan Bank in hiring a diverse group of college graduates and preparing them to be entry-level relationship managers is discussed. The objectives and procedures followed by the bank in recruitment and training of new staff are addressed. Trainees are screened for six mental abilities that correlate with success in this…

  10. 6. CONSTRUCTION PROGRESS VIEW (EXTERIOR) OF TANK, CABLE CHASE, AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. CONSTRUCTION PROGRESS VIEW (EXTERIOR) OF TANK, CABLE CHASE, AND MOUNDED BUNKER. CONSTRUCTION WAS 99 PERCENT COMPLETE. CAMERA IS FACING WEST. INEL PHOTO NUMBER 65-5435, TAKEN OCTOBER 20, 1965. - Idaho National Engineering Laboratory, Advanced Reentry Vehicle Fusing System, Scoville, Butte County, ID

  11. F-18 chase craft with NASA test pilots Schneider and Fulton

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Ed Schneider, (left), is the project pilot for the F-18 High Angle of Attack program at NASA's Dryden Flight Research Center, Edwards, California. He has been a NASA research pilot at Dryden since 1983. In addition to his assignment with the F-18 High Angle of Attack program, Schneider is a project pilot for the F-15B aeronautical research aircraft, the NASA NB-52B launch aircraft, and the SR-71 'Blackbird' aircraft. He is a Fellow and was the 1994 President of the Society of Experimental Test Pilots. In 1996 he was awarded the NASA Exceptional Service Medal. Schneider is seen here with Fitzhugh L. Fulton Jr., (right), who was a civilian research pilot at Dryden. from August 1, 1966, until July 3, 1986, following 23 years of service as a pilot in the U.S. Air Force. Fulton was the project pilot on all early tests of the 747 Shuttle Carrier Aircraft (SCA) used to air launch the Space Shuttle prototype Enterprise in the Approach and Landing Tests (ALT) at Dryden in l977. For his work in the ALT program, Fulton received NASA's Exceptional Service Medal. He also received the Exceptional Service Medal again in 1983 for flying the 747 SCA during the European tour of the Space Shuttle Enterprise. During his career at Dryden, Fulton was project pilot on NASA's NB-52B launch aircraft used to air launch a variety of piloted and unpiloted research aircraft, including the X-15s and lifting bodies. He flew the XB-70 prototype supersonic bomber on both NASA-USAF tests and NASA research flights during the late 1960s, attaining speeds exceeding Mach 3. He was also a project pilot on the YF-12A and YF-12C research program from April 14, 1969, until September 25, 1978. The F/A-18 Hornet seen behind them is used primarily as a safety chase and support aircraft at NASA's Dryden Flight Research Center, Edwards, Calif. As support aircraft, the F-18's are used for safety chase, pilot proficiency and aerial photography. As a safety chase aircraft, F-18's, flown by research pilots

  12. Exploring the Obscured Milky Way with Multi-Object Spectroscopy

    NASA Astrophysics Data System (ADS)

    Negueruela, I.; Clark, J. S.; Dorda, R.; González-Fernández, C.; Marco, A.; Monguió, M.

    2016-10-01

    Most of the Milky Way is hidden by dust clouds. Along many sightlines extinction grows to several magnitudes within just 2 or 3 kpc. High-mass stars on the other hand are so luminous that they can be seen, at least in the infrared, out to very large distances. They are short-lived and thus trace recent star formation and Galactic structure. If we were able to identify them in the middle of crowded Galactic Plane fields, we could probe a range of distances and extinctions that most spectroscopic surveys (and even Gaia) will fail to cover. Is it possible to tell a highly-reddened distant high-mass star from a nearby intrinsically faint and red star? We have been developing selection criteria that allow the identification of candidate obscured high-mass stars in different Galactic environments. Here we present a selection of results from several test observations carried out with AF2, AAOmega and FLAMES along different sightlines. The results are extremely encouraging. With the advent of large-scale photometric surveys, such as VVV, IPHAS or VPHAS+, we can refine search criteria to the point that next-generation instruments, such as WEAVE or MOONS, can be used to explore most of the obscured Milky Way.

  13. Principal as Curriculum Leader: Chase Manhattan Project.

    ERIC Educational Resources Information Center

    Petruzillo, Eileen; Scheinbart, Diane S.

    1986-01-01

    Describes a program initiated at a high school in New York City that identified learning styles of special education students in an effort to increase their achievement. Concludes that the program led to gains in motivation as well as achievement. Contains materials used to identify learning styles. (FL)

  14. Angular Clustering of Obscured Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Gandhi, Poshak; Garcet, O.; Disseau, L.; Pacaud, F.; Pierre, M.; Gueguen, A.; Alloin, D.; Chiappetti, L.; Gosset, E.; Maccagni, D.; Surdej, J.; Valtchanov, I.

    2006-09-01

    We describe the properties of X-ray point-like sources detected over 4.2 sq. degs. of the largest contiguous survey with XMM-Newton to date (the XMM-LSS survey) to fluxes of F2-10 keV 8x10-15 erg/s/cm2 and F0.5-2 keV 2x10-15 erg/s/cm2 respectively. For 1200 sources in the soft band, we find a two-point angular correlation function (ACF) signal similar to previous work, but no correlation for 400 sources in the hard band. A sample of 200 faint sources with hard X-ray spectra does show a 2-3 sigma positive signal with a power-law normalization theta0>40 arcsec. We discuss implications, including the fact that a large correlation length for obscured AGN is inconsistent with simple AGN Unification based on orientation only.

  15. Chasing the dreams of early connectionists.

    PubMed

    van den Heuvel, Martijn P; de Reus, Marcel A

    2014-07-16

    Mapping and examining the wiring pattern of neural systems is a fundamental pillar of neuroscience. In this Viewpoint, we review a recently described mesoscale connectome map of the mouse brain. We underscore the map's high spatial resolution and discuss key organizational network attributes of the presented connectome, its potential impact on neuroscience, and the general importance of connectome maps to obtain insight in the workings of the brain at a system's level.

  16. A NICMOS search for obscured supernovae in starburst galaxies

    NASA Astrophysics Data System (ADS)

    Maiolino, Roberto

    2003-07-01

    Recent near-IR monitoring campaigns were successful in detecting obscured supernovae {SNe} in starburst galaxies. The inferred SN rate is much higher than that obtained in previous optical campaigns, but it is still significanly lower than expected by the high level star formation of these systems. One possible explanation for the shortage of SNe is that most of them occur in the nuclear region, where the limited angular resolution of groundbased observations prevents their detection. We propose NICMOS SNAP observations of a sample of starburst galaxies already observed once by NICMOS, with the goal of exploiting its sensitivity and angular resolution to detect nuclear obscured SNe which might have been missed by groundbased surveys. These observation will allow to assess the real SN rate in starbust galaxies and deliver a sample of SN occurring in the extreme environment of galactic nuclei. We expect to detect more than 55 SNe {if the whole sample is observed}. If the number of SNe detected in the program is much lower than expected it would prompt for a revision of our understanding of the relation between the star formation rate and the SN rate.

  17. A Burst Chasing X-ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Hill, Joanne; Hill, Joe; Barthelmy, S.; Black, K.; Deines-Jones, P.; Jahoda, K.; Sakamoto, T.; Kaaret, P.; McConnell, M.; Bloser, P.; Macri, J.; Legere, J.; Ryan, J.; Smith, B., Jr.; Zhang, B.

    2007-01-01

    Tihs is a viewgraph presentation of a discussion of the X-ray Polarimeter. Gamma-ray bursts are one of the most powerful explosions in the universe and have been detected out to distances of almost 13 billion light years. The exact origin of these energetic explosions is still unknown but the resulting huge release of energy is thought to create a highly relativistic jet of material and a power-law distribution of electrons. There are several theories describing the origin of the prompt GRB emission that currently cannot be distinguished. Measurements of the linear polarization would provide unique and important constraints on the mechanisms thought to drive these powerful explosions. We present the design of a sensitive, and extremely versatile gamma-ray burst polarimeter. The instrument is a photoelectric polarimeter based on a time-projection chamber. The photoelectric time-projection technique combines high sensitivity with broad band-pass and is potentially the most powerful method between 2 and 100 keV where the photoelectric effect is the dominant interaction process We present measurements of polarized and unpolarized X-rays obtained with a prototype detector and describe the two mission concepts, the Gamma-Ray Burst Polarimeter (GRBP) for thc U S Naval Academy satellite MidSTAR-2, and thc Low Energy Polarimeter (LEP) onboard POET, a broadband polarimetry concept for a small explorer mission.

  18. A Burst Chasing X-ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Hill, Joanne E.; Barthelmy, Scott; Black, J. kevin; Deines-Jones, Philip; Jahoda, Keith; Sakamoto, Takanori; Kaaret, Philip; McConnell, Mark L.; Bloser, Peter F.; Macri, John R.; Legere, Jason S.; Ryan, James M.; Smith, Billy R., Jr.; Zhang, Bing

    2007-01-01

    Gamma-ray bursts are one of the most powerful explosions in the universe and have been detected out to distances of almost 13 billion light years. The exact origin of these energetic explosions is still unknown but the resulting huge release of energy is thought to create a highly relativistic jet of material and a power-law distribution of electrons. There are several theories describing the origin of the prompt GRB emission that currently cannot be distinguished. Measurements of the linear polarization would provide unique and important constraints on the mechanisms thought to drive these powerful explosions. We present the design of a sensitive, and extremely versatile gamma-ray burst polarimeter. The instrument is a photoelectric polarimeter based on a time-projection chamber. The photoelectric time-projection technique combines high sensitivity with broad band-pass and is potentially the most powerful method between 2 and 100 keV where the photoelectric effect 1s the dominant interaction process We present measurements of polarized and unpolarized X-rays obtained with a prototype detector and describe the two mission concepts, the Gamma-Ray Burst Polarimeter (GRBP) for thc U S Naval Academy satellite MidSTAR-2, and thc Low Energy Polarimeter (LEP) onboard POET, a broadband polarimetry concept for a small explorer mission.

  19. Chasing a Comet with a Solar Sail

    NASA Technical Reports Server (NTRS)

    Stough, Robert W.; Heaton, Andrew F.; Whorton, Mark S.

    2008-01-01

    Solar sail propulsion systems enable a wide range of missions that require constant thrust or high delta-V over long mission times. One particularly challenging mission type is a comet rendezvous mission. This paper presents optimal low-thrust trajectory designs for a range of sailcraft performance metrics and mission transit times that enables a comet rendezvous mission. These optimal trajectory results provide a trade space which can be parameterized in terms of mission duration and sailcraft performance parameters such that a design space for a small satellite comet chaser mission is identified. These results show that a feasible space exists for a small satellite to perform a comet chaser mission in a reasonable mission time.

  20. Reflections on the development of CHASE Children's Hospice Service.

    PubMed

    Menezes, A

    2001-01-01

    The tasks along the way to developing a children's hospice service are examined. CHASE Children's Hospice Service aims to establish a network of care for life-limited and life-threatened children, young people and their families. The services will be provided for families living mainly in SW London, Surrey and parts of West Sussex. They will comprise a source of palliative and respite care for the children and their families in their own homes (community care), backed-up by a respite care service in the related hospice at Artington, near Guildford (Christopher's).

  1. Chasing Nutrients with an Arctic Sedge

    NASA Astrophysics Data System (ADS)

    Iverson, S. L.; Schimel, J.

    2013-12-01

    Climate change has put the Arctic into a state of flux. Understanding the effects an altered climate will have on vegetation and nutrient cycling requires more knowledge of the key plant and soil functions of major arctic ecosystems. One of these ecosystems, moist acidic tussock tundra, is dominated by a single plant species, the tussock-forming sedge Eriophorum vaginatum. This plant has unusual underground biomass: long, fast-growing, non-branching, non-mycorrhizal roots. In contrast to many other plants in nutrient-limiting environments, this sedge is highly successful without maximizing its root surface area to volume ratio. The benefits of this growth strategy to the plants and its effects on the accompanying soil-microbe-plant relationships are not fully understood. One possibility is that the roots may help the plant take advantage of nutrients released into the active layer of soil as it thaws in the spring. The roots may also stimulate microbial activity, increasing nutrient turnover and availability. A study was undertaken to explore the nitrogen (N) and carbon (C) dynamics in these plants, as well as the microbial populations associated with active E. vaginatum roots. Intact tussock microcosms (plant and accompanying soil) were removed from the tundra and cultivated in transparent boxes. Half the plants were kept in light to encourage photosynthesis (and thus greater plant activity), while the other half was kept in the dark to inhibit it. Using a 15N isotopic tracer injected at the extremity of root penetration into the soil, the N uptake capacity of E. vaginatum roots at depth was explored. This uptake capacity is compared to measures of plant activity, microbial activity, and soil solution chemistry in order to paint a clearer picture of the role of E. vaginatum in the soil ecosystem.

  2. Chasing Lightning: Sferics, Tweeks and Whistlers

    NASA Astrophysics Data System (ADS)

    Webb, P. A.; Franzen, K.; Garcia, L.; Schou, P.; Rous, P.

    2008-12-01

    We all know what lightning looks like during a thunderstorm, but the visible flash we see is only part of the story. This is because lightning also generates light with other frequencies that we cannot perceive with our eyes, but which are just as real as visible light. Unlike the visible light from lightning, these other frequencies can carry the lightning's energy hundreds or thousands of miles across the surface of the Earth in the form of special signals called "tweeks" and "sferics". Some of these emissions can even travel tens of thousands of miles out into space before returning to the Earth as "whistlers". The INSPIRE Project, Inc is a non-profit scientific and educational corporation whose beginning mission was to bring the excitement of observing these very low frequency (VLF) natural radio waves emissions from lightning to high school students. Since 1989, INSPIRE has provided specially designed radio receiver kits to over 2,600 participants around the world to make observations of signals in the VLF frequency range. Many of these participants are using the VLF data they collect in very creative projects that include fiction, music and art exhibitions. During the Fall 2008 semester, the first INSPIRE based university-level course was taught at University of Maryland Baltimore County (UMBC) as part of its First-Year Seminar (FYS) series. The FYS classes are limited to 20 first-year students per class and are designed to create an active-learning environment that encourages student participation and discussion that might not otherwise occur in larger first-year classes. This presentation will cover the experiences gained from using the INSPIRE kits as the basis of a university course. This will include the lecture material that covers the basic physics of lightning, thunderstorms and the Earth's atmosphere, as well as the electronics required to understand the basic workings of the VLF kit. It will also cover the students assembly of the kit in an

  3. X-31 in Flight with F-18 Chase

    NASA Technical Reports Server (NTRS)

    1994-01-01

    One of two X-31 Enhanced Fighter Maneuverability Demonstrator aircraft (top), flown by an international test organization at NASA's Dryden Flight Research Center, Edwards, California, is seen here accompanied by a NASA F-18 chase aircraft during a research flight over the desert floor. The X-31 had a three-axis thrust-vectoring system, coupled with advanced flight controls, to allow it to maneuver tightly at very high angles of attack. The X-31 Enhanced Fighter Maneuverability (EFM) demonstrator flew at the Ames- Dryden Flight Research Facility, Edwards, California (redesignated the Dryden Flight Research Center in 1994) from February 1992 until 1995 and before that at the Air Force's Plant 42 in Palmdale, California. The goal of the project was to provide design information for the next generation of highly maneuverable fighter aircraft. This program demonstrated the value of using thrust vectoring (directing engine exhaust flow) coupled with an advanced flight control system to provide controlled flight to very high angles of attack. The result was a significant advantage over most conventional fighters in close-in combat situations. The X-31 flight program focused on agile flight within the post-stall regime, producing technical data to give aircraft designers a better understanding of aerodynamics, effectiveness of flight controls and thrust vectoring, and airflow phenomena at high angles of attack. Stall is a condition of an airplane or an airfoil in which lift decreases and drag increases due to the separation of airflow. Thrust vectoring compensates for the loss of control through normal aerodynamic surfaces that occurs during a stall. Post-stall refers to flying beyond the normal stall angle of attack, which in the X-31 was at a 30-degree angle of attack. During Dryden flight testing, the X-31 aircraft established several milestones. On November 6, 1992, the X-31 achieved controlled flight at a 70-degree angle of attack. On April 29, 1993, the second X-31

  4. X-31 in Flight with F-18 Chase

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A head-on view of the X-31 Enhanced Fighter Maneuverability Demonstrator aircraft (right), accompanied by a NASA F-18 chase aircraft during a research flight over the desert floor. The X-31 had a three-axis thrust-vectoring system, coupled with advanced flight controls, to allow it to maneuver tightly at very high angles of attack. The X-31 Enhanced Fighter Maneuverability (EFM) demonstrator flew at the Ames- Dryden Flight Research Facility, Edwards, California (redesignated the Dryden Flight Research Center in 1994) from February 1992 until 1995 and before that at the Air Force's Plant 42 in Palmdale, California. The goal of the project was to provide design information for the next generation of highly maneuverable fighter aircraft. This program demonstrated the value of using thrust vectoring (directing engine exhaust flow) coupled with an advanced flight control system to provide controlled flight to very high angles of attack. The result was a significant advantage over most conventional fighters in close-in combat situations. The X-31 flight program focused on agile flight within the post-stall regime, producing technical data to give aircraft designers a better understanding of aerodynamics, effectiveness of flight controls and thrust vectoring, and airflow phenomena at high angles of attack. Stall is a condition of an airplane or an airfoil in which lift decreases and drag increases due to the separation of airflow. Thrust vectoring compensates for the loss of control through normal aerodynamic surfaces that occurs during a stall. Post-stall refers to flying beyond the normal stall angle of attack, which in the X-31 was at a 30-degree angle of attack. During Dryden flight testing, the X-31 aircraft established several milestones. On November 6, 1992, the X-31 achieved controlled flight at a 70-degree angle of attack. On April 29, 1993, the second X-31 successfully executed a rapid minimum-radius, 180-degree turn using a post-stall maneuver, flying well

  5. Radio constraints on heavily obscured star formation within dark gamma-ray burst host galaxies

    SciTech Connect

    Perley, D. A.; Perley, R. A.

    2013-12-01

    Highly dust-obscured starbursting galaxies (submillimeter galaxies and their ilk) represent the most extreme sites of star formation in the distant universe and contribute significantly to overall cosmic star formation beyond z > 1.5. Some stars formed in these environments may also explode as gamma-ray bursts (GRBs) and contribute to the population of 'dark' bursts. Here we present Very Large Array wideband radio-continuum observations of 15 heavily dust-obscured Swift GRBs to search for radio synchrotron emission associated with intense star formation in their host galaxies. Most of these targets (11) are not detected. Of the remaining four objects, one detection is marginal, and for two others we cannot yet rule out the contribution of a long-lived radio afterglow. The final detection is secure, but indicates a star formation rate (SFR) roughly consistent with the dust-corrected UV-inferred value. Most galaxies hosting obscured GRBs are therefore not forming stars at extreme rates, and the amount of optical extinction seen along a GRB afterglow sightline does not clearly correlate with the likelihood that the host has a sufficiently high SFR to be radio-detectable. While some submillimeter galaxies do readily produce GRBs, these GRBs are often not heavily obscured—suggesting that the outer (modestly obscured) parts of these galaxies overproduce GRBs and the inner (heavily obscured) parts underproduce GRBs relative to their respective contributions to star formation, hinting at strong chemical or initial mass function gradients within these systems.

  6. A black hole nova obscured by an inner disk torus.

    PubMed

    Corral-Santana, J M; Casares, J; Muñoz-Darias, T; Rodríguez-Gil, P; Shahbaz, T; Torres, M A P; Zurita, C; Tyndall, A A

    2013-03-01

    Stellar-mass black holes (BHs) are mostly found in x-ray transients, a subclass of x-ray binaries that exhibit violent outbursts. None of the 50 galactic BHs known show eclipses, which is surprising for a random distribution of inclinations. Swift J1357.2-093313 is a very faint x-ray transient detected in 2011. On the basis of spectroscopic evidence, we show that it contains a BH in a 2.8-hour orbital period. Further, high-time-resolution optical light curves display profound dips without x-ray counterparts. The observed properties are best explained by the presence of an obscuring toroidal structure moving outward in the inner disk, seen at very high inclination. This observational feature should play a key role in models of inner accretion flows and jet collimation mechanisms in stellar-mass BHs. PMID:23449588

  7. A black hole nova obscured by an inner disk torus.

    PubMed

    Corral-Santana, J M; Casares, J; Muñoz-Darias, T; Rodríguez-Gil, P; Shahbaz, T; Torres, M A P; Zurita, C; Tyndall, A A

    2013-03-01

    Stellar-mass black holes (BHs) are mostly found in x-ray transients, a subclass of x-ray binaries that exhibit violent outbursts. None of the 50 galactic BHs known show eclipses, which is surprising for a random distribution of inclinations. Swift J1357.2-093313 is a very faint x-ray transient detected in 2011. On the basis of spectroscopic evidence, we show that it contains a BH in a 2.8-hour orbital period. Further, high-time-resolution optical light curves display profound dips without x-ray counterparts. The observed properties are best explained by the presence of an obscuring toroidal structure moving outward in the inner disk, seen at very high inclination. This observational feature should play a key role in models of inner accretion flows and jet collimation mechanisms in stellar-mass BHs.

  8. Group chase and escape model with chasers' interaction

    NASA Astrophysics Data System (ADS)

    Saito, Takuya; Nakamura, Tomomichi; Ohira, Toru

    2016-04-01

    Group chase and escape is a new direction of studying collective behaviors merged with the traditional mathematical problems of chases and escapes proposed by Kamimura and Ohira in 2010. In their model, the chasers recognize only the escapees and pursue the nearest neighbor escapee, and the escapees recognize only the chasers and flee from the nearest neighbor chaser. We call the basic moving rule the nearest opponent interaction (NOI) strategy. In this paper we introduce a new strategy in the model. It is a local interaction that the chasers do not get too close each other, where we call the chasers' local interaction (CLI) strategy. The result of comparisons of the two strategies shows that when the number of the chasers is relatively small compared to the number of the escapees, the trapping time by the CLI strategy is much shorter than that by the NOI strategy. On the other hand, when the number of the chasers is larger than that of the escapees, this advantage of the CLI strategy does not appear. Also, we find that although chasers form clusters (spatial aggregates of chasers) when we apply the NOI strategy, the clusters appear less when we apply the CLI strategy.

  9. Environmental Effects on Compulsive Tail Chasing in Dogs

    PubMed Central

    Tiira, Katriina; Hakosalo, Osmo; Kareinen, Lauri; Thomas, Anne; Hielm-Björkman, Anna; Escriou, Catherine; Arnold, Paul; Lohi, Hannes

    2012-01-01

    Obsessive Compulsive Disorder (OCD) is a neuropsychiatric disorder observed both in humans and animals. Examples of Canine Compulsive Disorder (CD) include excessive tail chasing (TC), light/shadow chasing and flank sucking. We performed a questionnaire survey to investigate the characteristics of compulsive (TC) and its possible associations with environmental correlates and personality in a pet population of 368 dogs from four dog breeds. We observed an early onset of TC at 3–6 months of age and a large variation in TC frequency in all breeds, with an overrepresentation of milder cases. Almost half of the TC dogs showed lowered responsiveness during bouts and displayed also other types of compulsions more often than the controls. Interestingly, dogs that received dietary supplements, especially vitamins and minerals, expressed less TC compared to dogs that did not receive any supplements. Neutered females had less TC, suggesting an influence of ovarian hormones on TC. Tail chasers were shyer and had separated earlier from their mothers than the controls. Finally, our genetic study did not find an association between TC and CDH2, a locus previously associated with the canine flank sucking compulsion. In conclusion, the early-onset and the variable nature of the repetitive behaviour, which is affected by environmental factors such as micronutrients, neutering and maternal care, share several similar components between canine and human compulsions and supports canine TC as a model for human OCD. PMID:22844513

  10. Significance chasing in research practice: Causes, consequences, and possible solutions

    PubMed Central

    Ware, Jennifer J.; Munafò, Marcus R.

    2016-01-01

    Background and Aims The low reproducibility of findings within the scientific literature is a growing concern. This may be due to many findings being false positives, which in turn can misdirect research effort and waste money. Methods We review factors that may contribute to poor study reproducibility and an excess of ‘significant’ findings within the published literature. Specifically, we consider the influence of current incentive structures, and the impact of these on research practices. Results The prevalence of false positives within the literature may be attributable to a number of questionable research practices, ranging from the relatively innocent and minor (e.g., unplanned post hoc tests), to the calculated and serious (e.g., fabrication of data). These practices may be driven by current incentive structures (e.g. pressure to publish), alongside the preferential emphasis placed by journals on novelty over veracity. There are a number of potential solutions to poor reproducibility, such as new publishing formats that emphasise the research question and study design, rather than the results obtained. This has the potential to minimise significance chasing and non-publication of null findings. Conclusions Significance chasing, questionable research practices, and poor study reproducibility are the unfortunate consequence of a “publish or perish” culture and a preference among journals for novel findings. It is likely that top-down change implemented by those with the ability to modify current incentive structure (e.g., funders and journals) will be required to address problems of poor reproducibility. PMID:25040652

  11. A SPECTACULAR OUTFLOW IN AN OBSCURED QUASAR

    SciTech Connect

    Greene, Jenny E.; Zakamska, Nadia L.; Smith, Paul S.

    2012-02-10

    SDSS J1356+1026 is a pair of interacting galaxies at redshift z = 0.123 that hosts a luminous obscured quasar in its northern nucleus. Here we present two long-slit Magellan LDSS-3 spectra that reveal a pair of symmetric {approx}10 kpc size outflows emerging from this nucleus, with observed expansion velocities of {approx}250 km s{sup -1} in projection. We present a kinematic model of these outflows and argue that the deprojected physical velocities of expansion are likely {approx}1000 km s{sup -1} and that the kinetic energy of the expanding shells is likely 10{sup 44-45} erg s{sup -1}, with an absolute minimum of >10{sup 42} erg s{sup -1}. Although a radio counterpart is detected at 1.4 GHz, it is faint enough that the quasar is considered to be radio quiet by all standard criteria, and there is no evidence of extended emission due to radio lobes, whether aged or continuously powered by an ongoing jet. We argue that the likely level of star formation is insufficient to power the observed energetic outflow and that SDSS J1356+1026 is a good case for radio-quiet quasar feedback. In further support of this hypothesis, polarimetric observations show that the direction of quasar illumination is coincident with the direction of the outflow.

  12. Environment and properties of obscured and unobscured active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Taormina, M.; Bornancini, C.

    We analyze the properties of obscured and unobscured active galactic nuclei selected using mid-infrared colors in the redshift range 1 < z < 3. We find that obscured objects are located in a denser local galaxy environment compared to the unobscured sample.

  13. HST Morphologies of z ˜ 2 Dust Obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Bussmann, R. S.; Dey, A.

    2009-10-01

    We present high spatial resolution Cycle~15 HST imaging of 31 z ˜ 2 Dust Obscured Galaxies (DOGs) in the Boötes Field of the NOAO Deep Wide-Field Survey. Although this subset of DOGs have mid-IR spectral features typical of AGN, all but one of the galaxies are spatially extended and not dominated by an unresolved component at rest-frame optical wavelengths. Sérsic profile fitting indicates effective radii of 1-5~kpc, roughly intermediate between SMGs and quiescent BzKs and DRGs. DOG morphologies suggest they are more dynamically relaxed than local ULIRGs. HST imaging of a different sample of DOGs in Boötes observed during Cycle~16 shows qualitative evidence for a higher rate of interaction compared to the Cycle~15 sample. If major mergers are the progenitors of DOGs, then our observations suggest that DOGs may represent various stages of a post-merger evolutionary phase.

  14. X-ray obscured AGN in the GOODS-N

    NASA Astrophysics Data System (ADS)

    Georgantopoulos, I.; Akylas, A.; Rovilos, E.; Xilouris, M.

    2010-07-01

    We explore the X-ray properties of the Dust Obscured Galaxies (DOGs) i.e. sources with f24μ/fR>1000. This population has been proposed to contain a significan fraction of Compton-thick sources at high redshift. In particular we study the X-ray spectra of the 14 DOGS detected in the CDFN 2Ms exposure. Their stacked spectrum is fla with Γ = 1+/-0.1 very similar to the stacked spectrum of the undetected DOGs (Γ = 0.8+/-0.2). However, many of our X-ray detected DOGs present only moderate absorption with column densities 1022

  15. Reflection in obscured Seyfert galaxies and the CXB

    NASA Astrophysics Data System (ADS)

    Walter, Roland

    We present a study of the average hard X-ray spectra of Seyfert galaxies obtained accumulating one billion seconds of Swift/BAT data and reaching a sensitivity of 20 micro-Cras in the hard X-rays. As already suggested by INTEGRAL data, this analysis confirms that midly obsured Seyfert 2 galaxies feature much more reflection than unabsorbed sources. The ratio of the average spectra of obscured and unobscured sources, derived with high accuracy, is characteristic of a reflection hump with a broad excess peaking at 40 keV. This large reflection cannot be explained easily by the unified model and points towards the clumpy torus model. It also provides a natural explanation for the peak of the cosmic X-ray background without requiring a large population of Compton thick sources.

  16. Toxic leucoencephalopathy after ‘chasing the dragon’

    PubMed Central

    Singh, Rajinder; Saini, Monica

    2015-01-01

    Toxic leucoencephalopathy (TLE) is a rare neurological complication of heroin abuse. ‘Chasing the dragon’ is an inhalational mode of heroin abuse that originated in Southeast Asia. Intriguingly, no cases of TLE have been reported from this region, although the inhalational mode of heroin abuse is common. We herein report the case of a middle-aged man with a history of polysubstance abuse who presented with progressive neurological symptoms and progressed to an uncommunicative state. While the initial impression was that of iatrogenic parkinsonism, diffuse leucoencephalopathy with sparing of the cerebellum was noted on magnetic resonance imaging. In view of his history of inhalational heroin abuse close to the onset of the neurological symptoms, a diagnosis of TLE was made. No clinical improvement was noted with administration of a dopaminergic agent. This is the first known case of delayed TLE following heroin inhalation from Southeast Asia with the unusual feature of cerebellar sparing. PMID:26106246

  17. Coplanar tail-chase aerial combat as a differential game

    NASA Technical Reports Server (NTRS)

    Merz, A. W.; Hague, D. S.

    1977-01-01

    A reduced-order version of the one-on-one aerial combat problem is studied as a pursuit-evasion differential game. The coplanar motion takes place at given speeds and given maximum available turn rates, and is described by three state equations which are equivalent to the range, bearing, and heading of one aircraft relative to the other. The purpose of the study is to determine those relative geometries from which either aircraft can be guaranteed a win, regardless of the maneuver strategies of the other. Termination is specified by the tail-chase geometry, at which time the roles of pursuer and evader are known. The roles are found in general, together with the associated optimal turn maneuvers, by solution of the differential game of kind. For the numerical parameters chosen, neither aircraft can win from the majority of possible initial conditions if the other turns optimally in certain critical geometries.

  18. Dust-obscured Galaxies in the Local Universe

    NASA Astrophysics Data System (ADS)

    Hwang, Ho Seong; Geller, Margaret J.

    2013-06-01

    We use Wide-field Infrared Survey Explorer (WISE), AKARI, and Galaxy Evolution Explorer (GALEX) data to select local analogs of high-redshift (z ~ 2) dust obscured galaxies (DOGs). We identify 47 local DOGs with S 12 μm/S 0.22 μm >= 892 and S 12 μm > 20 mJy at 0.05 < z < 0.08 in the Sloan Digital Sky Survey data release 7. The infrared (IR) luminosities of these DOGs are in the range 3.4 × 1010 (L ⊙) <~ L IR <~ 7.0 × 1011 (L ⊙) with a median L IR of 2.1 × 1011 (L ⊙). We compare the physical properties of local DOGs with a control sample of galaxies that have lower S 12 μm/S 0.22 μm but have similar redshift, IR luminosity, and stellar mass distributions. Both WISE 12 μm and GALEX near-ultraviolet (NUV) flux densities of DOGs differ from the control sample of galaxies, but the difference is much larger in the NUV. Among the 47 DOGs, 36% ± 7% have small axis ratios in the optical (i.e., b/a < 0.6), larger than the fraction among the control sample (17% ± 3%). There is no obvious sign of interaction for many local DOGs. No local DOGs have companions with comparable optical magnitudes closer than ~50 kpc. The large- and small-scale environments of DOGs are similar to the control sample. Many physical properties of local DOGs are similar to those of high-z DOGs, even though the IR luminosities of local objects are an order of magnitude lower than for the high-z objects: the presence of two classes (active galactic nuclei- and star formation-dominated) of DOGs, abnormal faintness in the UV rather than extreme brightness in the mid-IR, and diverse optical morphology. These results suggest a common underlying physical origin of local and high-z DOGs. Both seem to represent the high-end tail of the dust obscuration distribution resulting from various physical mechanisms rather than a unique phase of galaxy evolution.

  19. Dust-obscured galaxies in the local universe

    SciTech Connect

    Hwang, Ho Seong; Geller, Margaret J. E-mail: mgeller@cfa.harvard.edu

    2013-06-01

    We use Wide-field Infrared Survey Explorer (WISE), AKARI, and Galaxy Evolution Explorer (GALEX) data to select local analogs of high-redshift (z ∼ 2) dust obscured galaxies (DOGs). We identify 47 local DOGs with S {sub 12μm}/S {sub 0.22μm} ≥ 892 and S {sub 12μm} > 20 mJy at 0.05 < z < 0.08 in the Sloan Digital Sky Survey data release 7. The infrared (IR) luminosities of these DOGs are in the range 3.4 × 10{sup 10} (L {sub ☉}) ≲ L {sub IR} ≲ 7.0 × 10{sup 11} (L {sub ☉}) with a median L {sub IR} of 2.1 × 10{sup 11} (L {sub ☉}). We compare the physical properties of local DOGs with a control sample of galaxies that have lower S {sub 12μm}/S {sub 0.22μm} but have similar redshift, IR luminosity, and stellar mass distributions. Both WISE 12 μm and GALEX near-ultraviolet (NUV) flux densities of DOGs differ from the control sample of galaxies, but the difference is much larger in the NUV. Among the 47 DOGs, 36% ± 7% have small axis ratios in the optical (i.e., b/a < 0.6), larger than the fraction among the control sample (17% ± 3%). There is no obvious sign of interaction for many local DOGs. No local DOGs have companions with comparable optical magnitudes closer than ∼50 kpc. The large- and small-scale environments of DOGs are similar to the control sample. Many physical properties of local DOGs are similar to those of high-z DOGs, even though the IR luminosities of local objects are an order of magnitude lower than for the high-z objects: the presence of two classes (active galactic nuclei- and star formation-dominated) of DOGs, abnormal faintness in the UV rather than extreme brightness in the mid-IR, and diverse optical morphology. These results suggest a common underlying physical origin of local and high-z DOGs. Both seem to represent the high-end tail of the dust obscuration distribution resulting from various physical mechanisms rather than a unique phase of galaxy evolution.

  20. 38. INTERIOR VIEW OF TANK. Suspended wooden platform obscures bottom ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. INTERIOR VIEW OF TANK. Suspended wooden platform obscures bottom of tank No date - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  1. A physical model for z ~ 2 dust-obscured galaxies

    NASA Astrophysics Data System (ADS)

    Narayanan, Desika; Dey, Arjun; Hayward, Christopher C.; Cox, Thomas J.; Bussmann, R. Shane; Brodwin, Mark; Jonsson, Patrik; Hopkins, Philip F.; Groves, Brent; Younger, Joshua D.; Hernquist, Lars

    2010-09-01

    We present a physical model for the origin of z ~ 2 dust-obscured galaxies (DOGs), a class of high-redshift ultraluminous infrared galaxies (ULIRGs) selected at 24μm which are particularly optically faint (F24μm/FR > 1000). By combining N-body/smoothed particle hydrodynamic simulations of high-redshift galaxy evolution with 3D polychromatic dust radiative transfer models, we find that luminous DOGs (with F24 >~ 0.3mJy at z ~ 2) are well modelled as extreme gas-rich mergers in massive (~5 × 1012-1013Msolar) haloes, with elevated star formation rates (SFR; ~500-1000Msolaryr-1) and/or significant active galactic nuclei (AGN) growth , whereas less luminous DOGs are more diverse in nature. At final coalescence, merger-driven DOGs transition from being starburst dominated to AGN dominated, evolving from a `bump' to a power-law (PL) shaped mid-IR (Infrared Array Camera, IRAC) spectral energy distribution (SED). After the DOG phase, the galaxy settles back to exhibiting a `bump' SED with bluer colours and lower SFRs. While canonically PL galaxies are associated with being AGN dominated, we find that the PL mid-IR SED can owe both to direct AGN contribution and to a heavily dust obscured stellar bump at times that the galaxy is starburst dominated. Thus, PL galaxies can be either starburst or AGN dominated. Less luminous DOGs can be well-represented either by mergers or by massive (Mbaryon ~ 5 × 1011Msolar) secularly evolving gas-rich disc galaxies (with SFR >~ 50Msolaryr-1). By utilizing similar models as those employed in the submillimetre galaxy (SMG) formation study of Narayanan et al., we investigate the connection between DOGs and SMGs. We find that the most heavily star-forming merger-driven DOGs can be selected as submillimetre galaxies, while both merger-driven and secularly evolving DOGs typically satisfy the BzK selection criteria. The model SEDs from the simulated galaxies match observed data reasonably well, though Mrk 231 and Arp 220 templates provide

  2. Effect of predictability on the stress response to chasing in Atlantic salmon (Salmo salar L.) parr.

    PubMed

    Madaro, Angelico; Fernö, Anders; Kristiansen, Tore S; Olsen, Rolf Erik; Gorissen, Marnix; Flik, Gert; Nilsson, Jonatan

    2016-01-01

    The possibility to prepare for and respond to challenges in a proper manner is essential to cope with a changing environment, and learning allows fish to up or downregulate the stress response based on experience. The regulation of the response to predicted needs should be easier in more predictable environments. We exposed salmon parr to chasing of either 15 s (weak stressor) or 5 min (strong stressor) twice daily for a 7-day learning period, with chasing either announced by a 30 s light signal (conditioned) or not announced (unconditioned). The behavioural response to the light signal was different between the conditioned and unconditioned groups, demonstrating that conditioned groups associated the signal with chasing. We could, however, not demonstrate any effect on the stress response of anticipation. The fish habituated to repeated stress exposures with a similar decrease in oxygen hyperconsumption in all groups. Due to habituation, possible effects of predictable announcement of a stressor on the physiological stress response may not have been expressed in this study. Plasma cortisol concentrations 1h after light signal and chasing the day after the training period was moderate in all groups although higher after 5 min chasing (13 ng ml(-1)) than 15 s chasing (7 ng ml(-1)). There was no physiological stress response after exposure to the light signal only after the learning period. We argue that the benefit of predictability of stressors is limited when the fish have no way to avoid the stressor.

  3. Effect of predictability on the stress response to chasing in Atlantic salmon (Salmo salar L.) parr.

    PubMed

    Madaro, Angelico; Fernö, Anders; Kristiansen, Tore S; Olsen, Rolf Erik; Gorissen, Marnix; Flik, Gert; Nilsson, Jonatan

    2016-01-01

    The possibility to prepare for and respond to challenges in a proper manner is essential to cope with a changing environment, and learning allows fish to up or downregulate the stress response based on experience. The regulation of the response to predicted needs should be easier in more predictable environments. We exposed salmon parr to chasing of either 15 s (weak stressor) or 5 min (strong stressor) twice daily for a 7-day learning period, with chasing either announced by a 30 s light signal (conditioned) or not announced (unconditioned). The behavioural response to the light signal was different between the conditioned and unconditioned groups, demonstrating that conditioned groups associated the signal with chasing. We could, however, not demonstrate any effect on the stress response of anticipation. The fish habituated to repeated stress exposures with a similar decrease in oxygen hyperconsumption in all groups. Due to habituation, possible effects of predictable announcement of a stressor on the physiological stress response may not have been expressed in this study. Plasma cortisol concentrations 1h after light signal and chasing the day after the training period was moderate in all groups although higher after 5 min chasing (13 ng ml(-1)) than 15 s chasing (7 ng ml(-1)). There was no physiological stress response after exposure to the light signal only after the learning period. We argue that the benefit of predictability of stressors is limited when the fish have no way to avoid the stressor. PMID:26440316

  4. PaperChase: a user-friendly program for searching the biomedical literature.

    PubMed

    Lawson, R

    1990-06-01

    PaperChase is a computer program which provides an efficient interface to the National Library of Medicine's MEDLINE database of references to the biomedical literature. The database includes references (citations) and abstracts compiled from Index Medicus, the International Nursing Index and the Index to Dental Literature. PaperChase may be accessed using any computer terminal or personal computer with modem. No special knowledge of computers or biomedical terms is necessary. Simple menus enable the novice to search the biomedical literature without training. A command language speeds searching for the experienced user. PaperChase does not require the user to know the database's indexing terminology, called Medical Subject Headings. Everyday language may be used and PaperChase will translate, or "map", the user's search term into the required Medical Subject Heading. PaperChase monitors a search in progress and suggests additional Medical Subject Headings which can be used to broaden or narrow a search. The searcher can order a full-text photocopy of any reference found in PaperChase. Support documentation and a subscriber newsletter are provided at no charge. Trained search specialists are available to offer assistance and to answer questions. PMID:2192743

  5. X-ray Obscured AGN in the GOODS-N

    NASA Astrophysics Data System (ADS)

    Georgantopoulos, I.; Akylas, A.; Rovilos, E.; Xilouris, E.

    2010-07-01

    We explore the X-ray properties of the Dust Obscured Galaxies (DOGs) i.e. sources with f24μ / fR > 1000. This population has been proposed to contain a significant fraction of Compton-thick sources at high redshift. In particular we study the X-ray spectra of the 14 DOGS detected in the CDFN 2Ms exposure. Their stacked spectrum is flat with Γ=1±0.1 very similar to the stacked spectrum of the undetected DOGs (Γ=0.8±0.2). However, most of our X-ray detected DOGs present only moderate absorption with column densities 1022 < NH < 1024 cm-2. Only three sources (20%) present very flat spectra and are probably associated with reflection dominated Compton-thick sources. Our finding is rather at odds with papers which claim that the vast majority of DOGs are associated with Compton-thick sources. In any case, such sources at high redshift (z > 2) present limited interest for the X-ray background: the population synthesis models predict a contribution, for the z > 2 Compton-thick AGN, to the X-ray background flux at 30 keV, of less than 1 percent.

  6. Obscure gastrointestinal bleeding due to multifocal intestinal angiosarcoma

    PubMed Central

    Navarro-Chagoya, Dolores; Figueroa-Ruiz, Marco; López-Gómez, Javier; Nava-Leyva, Héctor; Álvarez-Ponce, Carlos Eduardo; Guzmán-Sombrero, Gustavo; Velazquez-Garcia, José

    2015-01-01

    Introduction Intestinal angiosarcomas are an extremely rare and aggressive vascular tumors, with a few cases reported in the literature. Presentation of case A 45 years-old male arrived to our hospital with intermittent gastrointestinal bleeding presenting melena and weight loss, he has antecedent of pelvic radiotherapy ten years before admission for an unknown pelvic tumor. Emergency surgery was required because of uncontrolled bleeding and hemodynamic instability. Histopathological findings revealed a multifocal high-grade epithelioid angiosarcoma, with cells reactive for CD31, keratins CKAE 1/AE3 and factor VIII. Discussion Angiosarcomas are aggressive tumors with a high rate of lymph node metastasis and peripheral organs. The diagnosis is difficult because it present nonspecific clinical presentation, radiological and histopathological findings. There are few reports of angiosarcoma involving the small intestine and the most common presentation are abdominal pain and gastrointestinal bleeding. There is not enough information for intestinal angiosarcoma secondary to radiation therapy, but there have been proposed criteria for diagnosis: no microscopic or clinical evidence of antecedent malignant lesion, angiosarcoma presented in the field of irradiation, long latency period between radiation and angiosarcoma and histological confirmation. We suspect our patient course with a secondary form of angiosarcoma. Therapy for bleeding angiosarcoma consists in control of bleeding and medical management to stabilize the patient. Once accomplished surgical resection is required. Conclusion We should keep in mind this tumors as a cause of obscure intestinal bleeding in patients with medical history of radiation therapy. PMID:25853844

  7. Mildly obscured active galaxies and the cosmic X-ray background

    NASA Astrophysics Data System (ADS)

    Esposito, V.; Walter, R.

    2016-05-01

    Context. The diffuse cosmic X-ray background (CXB) is the sum of the emission of discrete sources, mostly massive black-holes accreting matter in active galactic nuclei (AGN). The CXB spectrum differs from the integration of the spectra of individual sources, calling for a large population, undetected so far, of strongly obscured Compton-thick AGN. Such objects are predicted by unified models, which attribute most of the AGN diversity to their inclination on the line of sight, and play an important role for the understanding of the growth of black holes in the early Universe. Aims: The percentage of strongly obscured Compton-thick AGN at low redshift can be derived from the observed CXB spectrum, if we assume AGN spectral templates and luminosity functions. Methods: We show that high signal-to-noise stacked hard X-ray spectra, derived from more than a billion seconds of effective exposure time with the Swift/BAT instrument, imply that mildly obscured Compton-thin AGN feature a strong reflection and contribute massively to the CXB. Results: A population of Compton-thick AGN larger than that which is effectively detected is not required to reproduce the CXB spectrum, since no more than 6% of the CXB flux can be attributed to them. The stronger reflection observed in mildly obscured AGN suggests that the covering factor of the gas and dust surrounding their central engines is a key factor in shaping their appearance. These mildly obscured AGN are easier to study at high redshift than Compton-thick sources are.

  8. The nature of dust-obscured galaxies at z~2

    NASA Astrophysics Data System (ADS)

    Bussmann, Robert Shane

    I use observational evidence to examine the nature and role in galaxy evolution of a population of dust-obscured galaxies (DOGs) at z ˜ 2. These objects are selected with the Spitzer Space Telescope, are bright in the mid-infrared (mid-IR) but faint in the optical, and contribute a significant fraction of the luminosity density in the universe at z ˜ 2. The first component of my thesis is a morphological study using high spatial resolution imaging with the Hubble Space Telescope of two samples of DOGs. One set of 33 DOGs have mid-IR spectral features typical of an obscured active galactic nucleus (AGN) (called power-law DOGs), while the other set of 20 DOGs have a local maximum in their spectral energy distribution (SED) at rest-frame 1.6microm associated with stellar emission (called bump DOGs). The host galaxy dominates the light profile in all but two of these DOGs. In addition, bump DOGs are larger than power-law DOGs and exhibit more diffuse and irregular morphologies; these trends are consistent with expectations from simulations of major mergers in which bump DOGs evolve into power-law DOGs. The second component of my thesis is a study of the dust properties of DOGs, using sub-mm imaging of 12 power-law DOGs. These power-law DOGs are hyper-luminous (2 x 1013 L⊙ ) and have predominantly warm dust (Tdust > 35 -- 60 K). These results are consistent with an evolutionary sequence in which power-law DOGs represent a brief but important phase when AGN feedback heats the interstellar medium and quenches star-formation. The third component of my thesis is a study of the stellar masses and star-formation histories of DOGs, using stellar population synthesis models and broadband photometry in the rest-frame ultra-violet, optical, and near-IR. The best-fit quantities indicate bump DOGs are less massive than power-law DOGs. The relatively low stellar masses found from this line of analysis favor a merger-driven origin for ULIRGs at z ˜ 2.

  9. Predator pursuit strategies: how do falcons and hawks chase prey?

    NASA Astrophysics Data System (ADS)

    Kane, Suzanne Amador; Zamani, Marjon; Fulton, Andrew; Rosenthal, Lee

    2014-03-01

    This study reports on experiments on falcons, goshawks and red-tailed hawks wearing miniature videocameras mounted on their backs or heads while pursuing flying or ground-based prey. Videos of hunts recorded by the raptors were analyzed to determine apparent prey positions on their visual fields during pursuits. These video data then were interpreted using computer simulations of pursuit steering laws observed in insects and mammals. A comparison of the empirical and modeling data indicates that falcons use cues due to the apparent motion of prey on the falcon's visual field to track and capture flying prey via a form of motion camouflage. The falcons also were found to maintain their prey's image at visual angles consistent with using their shallow fovea. Results for goshawks and red-tailed hawks were analyzed for a comparative study of how pursuits of ground-based prey by accipeters and buteos differ from those used by falcons chasing flying prey. These results should prove relevant for understanding the coevolution of pursuit and evasion, as well as the development of computer models of predation on flocks,and the integration of sensory and locomotion systems in biomimetic robots.

  10. Reflection in obscured Seyfert galaxies and the CXB

    NASA Astrophysics Data System (ADS)

    Walter, Roland; Esposito, Valentino

    2015-08-01

    We present a study of the average hard X-ray spectra of Seyfert galaxies of different types obtained accumulating one billion seconds of Swift/BAT data and reaching a sensitivity of 20 micro-Crab in the hard X-rays. The resulting spectra are representative of the average emission of these objects (in the local Universe) and can be used as a template for the synthesis of the Cosmic X-ray Background.The ratio of the average spectra obtained for Compton-thin obscured and unobscured sources, derived with high accuracy, is characteristic of a reflection hump and confirms that midly obsured and Compton thin Seyfert 2 galaxies feature much more reflection than unabsorbed sources.This large reflection cannot be explained easily by the unified model and points towards the clumpy torus model. It also provides a natural explanation for the peak, intensity and spectral shape of the Cosmic X-ray Background without requiring a large population of Compton thick sources.

  11. GEMS Observations of Obscured Galactic Bulge Globular Clusters

    NASA Astrophysics Data System (ADS)

    Geisler, Douglas; Saracino, Sara; Dalessandro, Emanuele; Ferraro, Francesco; Lanzoni, Barbara; Mauro, Francesco; Villanova, Sandro; Moni Bidin, Christian; Miocchi, Paolo; Massari, Davide

    2016-01-01

    We will present results for several heavily obscured Galactic globular clusters lying in the bulge, including Liller 1 and NGC 6624. The observations were obtained exploiting the exceptional high-resolution capabilities of the near-IR camera GSAOI combined with the Gemini Multi-Conjugate Adaptive Optics System at the GEMINI South Telescope. The images in the J and K bands are generally sub-0.1", only slightly larger than the diffraction limit of the telescope, yielding the deepest and most accurate color-magnitude diagrams obtained so far from the ground for these clusters. We derived the structural and physical properties of both clusters, supplementing the GEMS data with data from the Vista Variables in the Via Lactea project. We were also able to investigate the age of NGC 6624. We find that Liller 1 is significantly less concentrated and less extended than previously thought. We estimated the mass of Liller 1 to be 2.3 million solar masses, comparable to that of the most massive clusters in the Galaxy. Also, Liller 1 has the second-highest collision rate among all star clusters in the Galaxy, thus confirming that it is an ideal environment for the formation of collisional objects (such as millisecond pulsars). The NGC 6624 CMD reveals the second knee of the mainsequence and allows us to determine a very accurate age of 12.0 +-0.5 Gyr.

  12. Sperm whale predator-prey interactions involve chasing and buzzing, but no acoustic stunning.

    PubMed

    Fais, A; Johnson, M; Wilson, M; Aguilar Soto, N; Madsen, P T

    2016-01-01

    The sperm whale carries a hypertrophied nose that generates powerful clicks for long-range echolocation. However, it remains a conundrum how this bizarrely shaped apex predator catches its prey. Several hypotheses have been advanced to propose both active and passive means to acquire prey, including acoustic debilitation of prey with very powerful clicks. Here we test these hypotheses by using sound and movement recording tags in a fine-scale study of buzz sequences to relate the acoustic behaviour of sperm whales with changes in acceleration in their head region during prey capture attempts. We show that in the terminal buzz phase, sperm whales reduce inter-click intervals and estimated source levels by 1-2 orders of magnitude. As a result, received levels at the prey are more than an order of magnitude below levels required for debilitation, precluding acoustic stunning to facilitate prey capture. Rather, buzzing involves high-frequency, low amplitude clicks well suited to provide high-resolution biosonar updates during the last stages of capture. The high temporal resolution helps to guide motor patterns during occasionally prolonged chases in which prey are eventually subdued with the aid of fast jaw movements and/or buccal suction as indicated by acceleration transients (jerks) near the end of buzzes. PMID:27340122

  13. Sperm whale predator-prey interactions involve chasing and buzzing, but no acoustic stunning

    PubMed Central

    Fais, A.; Johnson, M.; Wilson, M.; Aguilar Soto, N.; Madsen, P. T.

    2016-01-01

    The sperm whale carries a hypertrophied nose that generates powerful clicks for long-range echolocation. However, it remains a conundrum how this bizarrely shaped apex predator catches its prey. Several hypotheses have been advanced to propose both active and passive means to acquire prey, including acoustic debilitation of prey with very powerful clicks. Here we test these hypotheses by using sound and movement recording tags in a fine-scale study of buzz sequences to relate the acoustic behaviour of sperm whales with changes in acceleration in their head region during prey capture attempts. We show that in the terminal buzz phase, sperm whales reduce inter-click intervals and estimated source levels by 1–2 orders of magnitude. As a result, received levels at the prey are more than an order of magnitude below levels required for debilitation, precluding acoustic stunning to facilitate prey capture. Rather, buzzing involves high-frequency, low amplitude clicks well suited to provide high-resolution biosonar updates during the last stages of capture. The high temporal resolution helps to guide motor patterns during occasionally prolonged chases in which prey are eventually subdued with the aid of fast jaw movements and/or buccal suction as indicated by acceleration transients (jerks) near the end of buzzes. PMID:27340122

  14. Sperm whale predator-prey interactions involve chasing and buzzing, but no acoustic stunning.

    PubMed

    Fais, A; Johnson, M; Wilson, M; Aguilar Soto, N; Madsen, P T

    2016-06-24

    The sperm whale carries a hypertrophied nose that generates powerful clicks for long-range echolocation. However, it remains a conundrum how this bizarrely shaped apex predator catches its prey. Several hypotheses have been advanced to propose both active and passive means to acquire prey, including acoustic debilitation of prey with very powerful clicks. Here we test these hypotheses by using sound and movement recording tags in a fine-scale study of buzz sequences to relate the acoustic behaviour of sperm whales with changes in acceleration in their head region during prey capture attempts. We show that in the terminal buzz phase, sperm whales reduce inter-click intervals and estimated source levels by 1-2 orders of magnitude. As a result, received levels at the prey are more than an order of magnitude below levels required for debilitation, precluding acoustic stunning to facilitate prey capture. Rather, buzzing involves high-frequency, low amplitude clicks well suited to provide high-resolution biosonar updates during the last stages of capture. The high temporal resolution helps to guide motor patterns during occasionally prolonged chases in which prey are eventually subdued with the aid of fast jaw movements and/or buccal suction as indicated by acceleration transients (jerks) near the end of buzzes.

  15. Geology and hydrogeology of Naval Air Station Chase Field and Naval Auxiliary Landing Field Goliad, Bee and Goliad counties, Texas

    USGS Publications Warehouse

    Snyder, G.L.

    1995-01-01

    Large vertical hydraulic-head gradients are present between the unconfined Evangeline aquifer and confined Fleming aquifers at Naval Air Station Chase Field and Naval Auxiliary Landing Field Goliad. These gradients, together with the results of the aquifer test at Naval Air Station Chase Field and assumed characteristics of the confining units, indicate that downward flow of ground water probably occurs from the water-table aquifer to the underlying aquifers. The rate of downward flow between the two confined Fleming aquifers (from A-sand to B-sand) can be approximated using an estimate of vertical hydraulic conductivity of the intervening confining unit obtained from assumed storage characteristics and data from the aquifer test. Under the relatively high vertical hydraulic-head gradient induced by the aquifer test, ground-water movement from the A-sand aquifer to the B-sand aquifer could require about 490 years; and about 730 years under the natural gradient. Future increases in ground-water withdrawals from the B-sand aquifer might increase downward flow in the aquifer system of the study area.

  16. Proteomic Analysis of Protein Turnover by Metabolic Whole Rodent Pulse-Chase Isotopic Labeling and Shotgun Mass Spectrometry Analysis.

    PubMed

    Savas, Jeffrey N; Park, Sung Kyu; Yates, John R

    2016-01-01

    The analysis of protein half-life and degradation dynamics has proven critically important to our understanding of a broad and diverse set of biological conditions ranging from cancer to neurodegeneration. Historically these protein turnover measures have been performed in cells by monitoring protein levels after "pulse" labeling of newly synthesized proteins and subsequent chase periods. Comparing the level of labeled protein remaining as a function of time to the initial level reveals the protein's half-life. In this method we provide a detailed description of the workflow required for the determination of protein turnover rates on a whole proteome scale in vivo. Our approach starts with the metabolic labeling of whole rodents by restricting all the nitrogen in their diet to exclusively nitrogen-15 in the form of spirulina algae. After near complete organismal labeling with nitrogen-15, the rodents are then switched to a normal nitrogen-14 rich diet for time periods of days to years. Tissues are harvested, the extracts are fractionated, and the proteins are digested to peptides. Peptides are separated by multidimensional liquid chromatography and analyzed by high resolution orbitrap mass spectrometry (MS). The nitrogen-15 containing proteins are then identified and measured by the bioinformatic proteome analysis tools Sequest, DTASelect2, and Census. In this way, our metabolic pulse-chase approach reveals in vivo protein decay rates proteome-wide. PMID:26867752

  17. Decoding Biosynthetic Pathways in Plants by Pulse-Chase Strategies Using 13CO2 as a Universal Tracer †

    PubMed Central

    Bacher, Adelbert; Chen, Fan; Eisenreich, Wolfgang

    2016-01-01

    13CO2 pulse-chase experiments monitored by high-resolution NMR spectroscopy and mass spectrometry can provide 13C-isotopologue compositions in biosynthetic products. Experiments with a variety of plant species have documented that the isotopologue profiles generated with 13CO2 pulse-chase labeling are directly comparable to those that can be generated by the application of [U-13C6]glucose to aseptically growing plants. However, the application of the 13CO2 labeling technology is not subject to the experimental limitations that one has to take into account for experiments with [U-13C6]glucose and can be applied to plants growing under physiological conditions, even in the field. In practical terms, the results of biosynthetic studies with 13CO2 consist of the detection of pairs, triples and occasionally quadruples of 13C atoms that have been jointly contributed to the target metabolite, at an abundance that is well above the stochastic occurrence of such multiples. Notably, the connectivities of jointly transferred 13C multiples can have undergone modification by skeletal rearrangements that can be diagnosed from the isotopologue data. As shown by the examples presented in this review article, the approach turns out to be powerful in decoding the carbon topology of even complex biosynthetic pathways. PMID:27429012

  18. Obscurity and Gender Resistance in Patricia Duncker's James Miranda Barry

    PubMed Central

    Funke, Jana

    2012-01-01

    Since his death in 1865, military surgeon James Barry has alternately been classified as a cross-dressing woman or as an intersexed individual. Patricia Duncker's novel James Miranda Barry (1999) poses an important challenge to such readings, as it does not reveal any foundational truth about Barry's sex. Resting on obscurity rather than revelation, the text frustrates the desire to know the past in terms of gender binaries and stable sexual identity categories. Drawing on feminist and queer theorisations of the relation between gender and time, this essay demonstrates that Duncker's use of obscurity opens up alternative strategies of gender resistance. PMID:25400502

  19. THE OBSCURED FRACTION OF ACTIVE GALACTIC NUCLEI IN THE XMM-COSMOS SURVEY: A SPECTRAL ENERGY DISTRIBUTION PERSPECTIVE

    SciTech Connect

    Lusso, E.; Hennawi, J. F.; Richards, G. T.; Comastri, A.; Zamorani, G.; Vignali, C.; Gilli, R.; Treister, E.; Schawinski, K.; Salvato, M.

    2013-11-10

    The fraction of active galactic nucleus (AGN) luminosity obscured by dust and re-emitted in the mid-IR is critical for understanding AGN evolution, unification, and parsec-scale AGN physics. For unobscured (Type 1) AGNs, where we have a direct view of the accretion disk, the dust covering factor can be measured by computing the ratio of re-processed mid-IR emission to intrinsic nuclear bolometric luminosity. We use this technique to estimate the obscured AGN fraction as a function of luminosity and redshift for 513 Type 1 AGNs from the XMM-COSMOS survey. The re-processed and intrinsic luminosities are computed by fitting the 18 band COSMOS photometry with a custom spectral energy distribution fitting code, which jointly models emission from hot dust in the AGN torus, from the accretion disk, and from the host galaxy. We find a relatively shallow decrease of the luminosity ratio as a function of L{sub bol}, which we interpret as a corresponding decrease in the obscured fraction. In the context of the receding torus model, where dust sublimation reduces the covering factor of more luminous AGNs, our measurements require a torus height that increases with luminosity as h ∝ L{sub bol}{sup 0.3-0.4}. Our obscured-fraction-luminosity relation agrees with determinations from Sloan Digital Sky Survey censuses of Type 1 and Type 2 quasars and favors a torus optically thin to mid-IR radiation. We find a much weaker dependence of the obscured fraction on 2-10 keV luminosity than previous determinations from X-ray surveys and argue that X-ray surveys miss a significant population of highly obscured Compton-thick AGNs. Our analysis shows no clear evidence for evolution of the obscured fraction with redshift.

  20. RING-APODIZED VORTEX CORONAGRAPHS FOR OBSCURED TELESCOPES. I. TRANSMISSIVE RING APODIZERS

    SciTech Connect

    Mawet, D.; Pueyo, L.; Carlotti, A.; Mennesson, B.; Serabyn, E.; Wallace, J. K.

    2013-11-01

    The vortex coronagraph (VC) is a new generation small inner working angle (IWA) coronagraph currently offered on various 8 m class ground-based telescopes. On these observing platforms, the current level of performance is not limited by the intrinsic properties of actual vortex devices, but by wavefront control residuals and incoherent background (e.g., thermal emission of the sky), or the light diffracted by the imprint of the secondary mirror and support structures on the telescope pupil. In the particular case of unfriendly apertures (mainly large central obscuration) when very high contrast is needed (e.g., direct imaging of older exoplanets with extremely large telescopes or space-based coronagraphs), a simple VC, like most coronagraphs, cannot deliver its nominal performance because of the contamination due to the diffraction from the obscured part of the pupil. Here, we propose a novel yet simple concept that circumvents this problem. We combine a vortex phase mask in the image plane of a high-contrast instrument with a single pupil-based amplitude ring apodizer, tailor-made to exploit the unique convolution properties of the VC at the Lyot-stop plane. We show that such a ring-apodized vortex coronagraph (RAVC) restores the perfect attenuation property of the VC regardless of the size of the central obscuration, and for any (even) topological charge of the vortex. More importantly, the RAVC maintains the IWA and conserves a fairly high throughput, which are signature properties of the VC.

  1. The Landmark Decision that Faded into Historical Obscurity

    ERIC Educational Resources Information Center

    Nance, Molly

    2007-01-01

    This article takes a look at the Mendez v. Westminster School District, a landmark case that faded into historical obscurity. In the 1940s, Gonzalo and Felicita Mendez wanted their three children to attend the school nearest their farm, which was the 17th Street Elementary School in Westminster. But in the Westminster, Orange County, El Medina,…

  2. Anatomy of the AGN in NGC 5548. VII. Swift study of obscuration and broadband continuum variability

    NASA Astrophysics Data System (ADS)

    Mehdipour, M.; Kaastra, J. S.; Kriss, G. A.; Cappi, M.; Petrucci, P.-O.; De Marco, B.; Ponti, G.; Steenbrugge, K. C.; Behar, E.; Bianchi, S.; Branduardi-Raymont, G.; Costantini, E.; Ebrero, J.; Di Gesu, L.; Matt, G.; Paltani, S.; Peterson, B. M.; Ursini, F.; Whewell, M.

    2016-04-01

    We present our investigation into the long-term variability of the X-ray obscuration and optical-UV-X-ray continuum in the Seyfert 1 galaxy NGC 5548. In 2013 and 2014, the Swift observatory monitored NGC 5548 on average every day or two, with archival observations reaching back to 2005, totalling about 670 ks of observing time. Both broadband spectral modelling and temporal rms variability analysis are applied to the Swift data. We disentangle the variability caused by absorption, due to an obscuring weakly-ionised outflow near the disk, from variability of the intrinsic continuum components (the soft X-ray excess and the power law) originating in the disk and its associated coronae. The spectral model that we apply to this extensive Swift data is the global model that we derived for NGC 5548 from analysis of the stacked spectra from our multi-satellite campaign of 2013 (including XMM-Newton, NuSTAR, and HST). The results of our Swift study show that changes in the covering fraction of the obscurer is the primary and dominant cause of variability in the soft X-ray band on timescales of 10 days to ~5 months. The obscuring covering fraction of the X-ray source is found to range between 0.7 and nearly 1.0. The contribution of the soft excess component to the X-ray variability is often much less than that of the obscurer, but it becomes comparable when the optical-UV continuum flares up. We find that the soft excess is consistent with being the high-energy tail of the optical-UV continuum and can be explained by warm Comptonisation: up-scattering of the disk seed photons in a warm, optically thick corona as part of the inner disk. To this date, the Swift monitoring of NGC 5548 shows that the obscurer has been continuously present in our line of sight for at least 4 years (since at least February 2012).

  3. Radio recombination lines from obscured quasars with the SKA

    NASA Astrophysics Data System (ADS)

    Manti, S.; Gallerani, S.; Ferrara, A.; Feruglio, C.; Graziani, L.; Bernardi, G.

    2016-02-01

    We explore the possibility of detecting hydrogen radio recombination lines from 0 < z < 10 quasars. We compute the expected Hnα flux densities as a function of absolute magnitude and redshift by considering (i) the range of observed active galactic nucleus spectral indices from UV to X-ray bands, (ii) secondary ionizations from X-ray photons, and (iii) stimulated emission due to non-thermal radiation. All these effects are important to determine the line fluxes. We find that the combination of slopes: αX,hard = -1.11, αX,soft = -0.7, αEUV = -1.3, αUV = -1.7, maximizes the expected flux, fHnα ≈ 10 μJy for z ˜ 7 quasars with MAB = -27 in the n ˜ 50 lines; allowed spectral energy distribution variations produce variations by a factor of 3 around this value. Secondaries boost the line intensity by a factor of 2-4 , while stimulated emission in high-z quasars with MAB ≈ -26 provides an extra boost to radio recombination line flux observed at ν ˜ 1 GHz if recombinations arise in H II regions with Te ≈ 103 - 5 K, ne ≈ 103 - 5 cm-3. We compute the sensitivity required for a 5σ detection of Hnα lines using the Square Kilometre Array (SKA), finding that the SKA-MID could detect sources with MAB ≲ -27 (MAB ≲ -26) at z ≲ 8 (z ≲ 3) in less than 100 h of observing time. These observations could open new paths to searches for obscured SMBH progenitors, complementing X-ray, optical/IR and sub-mm surveys.

  4. PRIMUS: OBSCURED STAR FORMATION ON THE RED SEQUENCE

    SciTech Connect

    Zhu Guangtun; Blanton, Michael R.; Burles, Scott M.; Coil, Alison L.; Moustakas, John; Aird, James; Cool, Richard J.; Eisenstein, Daniel J.; Wong, Kenneth C.

    2011-01-10

    We quantify the fraction of galaxies at moderate redshifts (0.1 < z < 0.5) that appear red-and-dead in the optical, but in fact contain obscured star formation detectable in the infrared (IR), with the PRIsm MUlti-object Survey (PRIMUS). PRIMUS has measured {approx}120,000 robust redshifts with a precision of {sigma}{sub z}/(1 + z) {approx} 0.5% over 9.1 deg{sup 2} of the sky to the depth of i {approx} 23 (AB), up to redshift z {approx} 1. We specifically targeted 6.7 deg{sup 2} fields with existing deep IR imaging from the Spitzer Space Telescope from the SWIRE and S-COSMOS surveys. We select in these fields an i-band flux-limited sample (i < 20 mag in the SWIRE fields and i < 21 mag in the S-COSMOS field) of 3310 red-sequence galaxies at 0.1 < z < 0.5 for which we can reliably classify obscured star-forming (SF) and quiescent galaxies using IR color. Our sample constitutes the largest galaxy sample at intermediate redshift to study obscured star formation on the red sequence, and we present the first quantitative analysis of the fraction of obscured SF galaxies as a function of luminosity. We find that on average, at L {approx} L*, about 15% of red-sequence galaxies have IR colors consistent with SF galaxies. The percentage of obscured SF galaxies increases by {approx}8% per mag with decreasing luminosity from the highest luminosities to L {approx} 0.2 L*. Our results suggest that a significant fraction of red-sequence galaxies have ongoing star formation and that galaxy evolution studies based on optical color therefore need to account for this complication.

  5. GammeV and GammeV-CHASE

    SciTech Connect

    Wester, W.; /Fermilab

    2011-11-01

    Physics beyond the Standard Model might include Weakly Interacting Slim Particles (WISPs) that address questions such as what is the nature of dark matter or even shed insight into the underlying nature of dark energy. WISPs are a general class of particles that include axions, axion-like particles, hidden sector photons, milli-charged particles, chameleons, etc. The GammeV (Gamma to milli-eV) experiment originated in 2007 in order to test a positive anomalous axion-like particle interpretation of the PVLAS experiment which was not evident in subsequent data. The experiment was also motivated as it was realized that the milli-eV scale appears naturally in a see-saw between the electroweak and Planck scales, neutrino mass differences, the dark energy density, and the possible mass for certain dark matter candidates. GammeV was first to exclude both a scalar and pseudoscalar axion-like particle interpretation of the anomalous PVLAS result setting a limit of around 3.1 x 10{sup -7} GeV{sup -1} on the coupling to photons for low mass axion-like particles. It has also been found that the parameter space of a variety of other WISP candidates is both largely unexplored and is accessible by modest experiments employing lasers and possibly accelerator magnets. GammeV data has also been used to set limits on possible hidden sector photons. Further work by the GammeV team has focused on a reconfiguration of the apparatus to be sensitive to possible chameleon particles. Chameleons are scalar (or pseudoscalar) particles that couple to the stress energy tensor in a potential such that their properties depend on their environment. In particular, a chameleon acquires an effective mass which increases with local matter density, {rho}. For a certain class of such potentials, the chameleon field has properties that might explain dark energy. GammeV set the first limits on the coupling of chameleons to photons. A dedicated follow-up experiment, GammeV-CHASE, (CHameleon Afterglow

  6. Contaminant levels in eggs of American white pelicans, Pelecanus erythrorhynchos, from Chase Lake, North Dakota

    USGS Publications Warehouse

    Pietz, Pamela J.; Sovada, Marsha A.; Custer, Christine M.; Custer, Thomas W.; Johnson, Kevin M.

    2008-01-01

    American White Pelicans (Pelecanus erythrorhynchos) are colonial nesters, making them susceptible to site-specific mortality factors. One of the largest known breeding colonies is at Chase Lake National Wildlife Refuge in North Dakota. In 2004, this colony suffered total reproductive failure. In 2005, we collected abandoned eggs from this colony to test for environmental contaminants. Nine eggs were analyzed for 28 organochlorine pesticides, total polychlorinated biphenyls, and 26 inorganic elements. Based on concentrations in this sample of eggs and levels linked to reproductive problems in birds, adult pelicans in the Chase Lake breeding colony are not at known risk from any of the environmental contaminants we measured.

  7. Half of the Most Luminous Quasars May Be Obscured: Investigating the Nature of WISE-Selected Hot Dust-Obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Assef, R. J.; Eisenhardt, P. R. M.; Stern, D.; Tsai, C.-W.; Wu, J.; Wylezalek, D.; Blain, A. W.; Bridge, C. R.; Donoso, E.; Gonzales, A.; Griffith, R. L.; Jarrett, T. H.

    2015-05-01

    The Wide-field Infrared Survey Explorer mission has unveiled a rare population of high-redshift (z = 1-4.6), dusty, hyper-luminous galaxies, with infrared luminosities {{L}IR}\\gt {{10}13} {{L}⊙ }, and sometimes exceeding {{10}14} {{L}⊙ }. Previous work has shown that their dust temperatures and overall far-infrared spectral energy distributions (SEDs) are significantly hotter than expected to be powered by star formation. We present here an analysis of the rest-frame optical through mid-infrared SEDs for a large sample of these so-called “hot, dust-obscured galaxies” (Hot DOGs). We find that the SEDs of Hot DOGs are generally well modeled by the combination of a luminous, yet obscured active galactic nuclei (AGNs) that dominates the rest-frame emission at λ \\gt 1 μ m and the bolometric luminosity output, and a less luminous host galaxy that is responsible for the bulk of the rest optical/UV emission. Even though the stellar mass of the host galaxies may be as large as 1011-1012 M⊙, the AGN emission, with a range of luminosities comparable to those of the most luminous QSOs known, require that either Hot DOGs have black hole masses significantly in excess of the local relations, or that they radiate significantly above the Eddington limit, at a level at least 10 times more efficiently than z ˜ 2 QSOs. We show that, while rare, the number density of Hot DOGs is comparable to that of equally luminous but unobscured (i.e., Type 1) QSOs. This may be at odds with the trend suggested at lower luminosities for the fraction of obscured AGNs to decrease with increasing luminosity. That trend may, instead, reverse at higher luminosities. Alternatively, Hot DOGs may not be the torus-obscured counterparts of the known optically selected, largely unobscured, hyper-luminous QSOs, and may represent a new component of the galaxy evolution paradigm. Finally, we discuss the environments of Hot DOGs and statistically show that these objects are in regions as dense as

  8. Heavily obscured quasar host galaxies at z ∼ 2 are discs, not major mergers

    NASA Astrophysics Data System (ADS)

    Schawinski, Kevin; Simmons, Brooke D.; Urry, C. Megan; Treister, Ezequiel; Glikman, Eilat

    2012-09-01

    We explore the nature of heavily obscured quasar host galaxies at z˜ 2 using deep Hubble Space Telescope Wide Field Camera 3/infrared imaging of 28 dust-obscured galaxies (DOGs) to investigate the role of major mergers in driving black hole growth. The high levels of obscuration of the quasars selected for this study act as a natural coronagraph, blocking the quasar light and allowing a clear view of the underlying host galaxy. The sample of heavily obscured quasars represents a significant fraction of the cosmic mass accretion on supermassive black holes as the quasars have inferred bolometric luminosities around the break of the quasar luminosity function. We find that only a small fraction (4 per cent, at most 11-25 per cent) of the quasar host galaxies are major mergers. Fits to their surface brightness profiles indicate that 90 per cent of the host galaxies are either disc dominated, or have a significant disc. This disc-like host morphology, and the corresponding weakness of bulges, is evidence against major mergers and suggests that secular processes are the predominant driver of massive black hole growth. Finally, we suggest that the coincidence of mergers and active galactic nucleus activity is luminosity dependent, with only the most luminous quasars being triggered mostly by major mergers. a MUSYC catalogue ID, see Cardamone et al. (2010). Objects with X-ray detections are marked with *. b See images shown in Fig. 1. c The ratio of the host luminosity to the point source luminosity, reported only when GALFIT requires an unresolved object to yield a physical fit. This may be due to an AGN point source (in the case of the X-ray-detected DOGs) or an unresolved bulge or central concentration, i.e. a central bulge. d See Fig. 2.

  9. Evaluation of diesel fleet emissions and control policies from plume chasing measurements of on-road vehicles

    NASA Astrophysics Data System (ADS)

    Lau, Chui Fong; Rakowska, Agata; Townsend, Thomas; Brimblecombe, Peter; Chan, Tat Leung; Yam, Yat Shing; Močnik, Griša; Ning, Zhi

    2015-12-01

    Vehicle emissions are an important source of urban air pollution. Diesel fuelled vehicles, although constituting a relatively small fraction of fleet population in many cities, are significant contributors to the emission inventory due to their often long mileage for goods and public transport. Recent classification of diesel exhaust as carcinogenic by the World Health Organization also raises attention to more stringent control of diesel emissions to protect public health. Although various mandatory and voluntary based emission control measures have been implemented in Hong Kong, there have been few investigations to evaluate if the fleet emission characteristics have met desired emission reduction objectives and if adoption of an Inspection/Maintenance (I/M) programme has been effective in achieving these objectives. The limitations are partially due to the lack of cost-effective approaches for the large scale characterisation of fleet based emissions to assess the effectiveness of control measures and policy. This study has used a plume chasing method to collect a large amount of on-road vehicle emission data of Hong Kong highways and a detailed analysis was carried out to provide a quantitative evaluation of the emission characteristics in terms of the role of high and super-emitters in total emission reduction, impact of after-treatment on the multi-pollutants reduction strategy and the trend of NO2 emissions with newer emission standards. The study revealed that not all the high-emitters are from those vehicles of older Euro emission standards. Meanwhile, there is clear evidence that high-emitters for one pollutant may not be a high-emitter for another pollutant. Multi-pollutant control strategy needs to be considered in the enactment of the emission control policy which requires more comprehensive retrofitting technological solutions and matching I/M programme to ensure the proper maintenance of fleets. The plume chasing approach used in this study also

  10. OBSCURATION BY GAS AND DUST IN LUMINOUS QUASARS

    SciTech Connect

    Usman, S. M.; Murray, S. S.; Hickox, R. C.; Brodwin, M.

    2014-06-10

    We explore the connection between absorption by neutral gas and extinction by dust in mid-infrared (IR) selected luminous quasars. We use a sample of 33 quasars at redshifts 0.7 < z ≲ 3 in the 9 deg{sup 2} Boötes multiwavelength survey field that are selected using Spitzer Space Telescope Infrared Array Camera colors and are well-detected as luminous X-ray sources (with >150 counts) in Chandra observations. We divide the quasars into dust-obscured and unobscured samples based on their optical to mid-IR color, and measure the neutral hydrogen column density N {sub H} through fitting of the X-ray spectra. We find that all subsets of quasars have consistent power law photon indices Γ ≈ 1.9 that are uncorrelated with N {sub H}. We classify the quasars as gas-absorbed or gas-unabsorbed if N {sub H} > 10{sup 22} cm{sup –2} or N {sub H} < 10{sup 22} cm{sup –2}, respectively. Of 24 dust-unobscured quasars in the sample, only one shows clear evidence for significant intrinsic N {sub H}, while 22 have column densities consistent with N {sub H} < 10{sup 22} cm{sup –2}. In contrast, of the nine dust-obscured quasars, six show evidence for intrinsic gas absorption, and three are consistent with N {sub H} < 10{sup 22} cm{sup –2}. We conclude that dust extinction in IR-selected quasars is strongly correlated with significant gas absorption as determined through X-ray spectral fitting. These results suggest that obscuring gas and dust in quasars are generally co-spatial, and confirm the reliability of simple mid-IR and optical photometric techniques for separating quasars based on obscuration.

  11. A Significant Population of Very Luminous Dust-Obscured Galaxies at Redshift z ~ 2

    NASA Astrophysics Data System (ADS)

    Dey, Arjun; Soifer, B. T.; Desai, Vandana; Brand, Kate; Le Floc'h, Emeric; Brown, Michael J. I.; Jannuzi, Buell T.; Armus, Lee; Bussmann, Shane; Brodwin, Mark; Bian, Chao; Eisenhardt, Peter; Higdon, Sarah J.; Weedman, Daniel; Willner, S. P.

    2008-04-01

    The Spitzer Space Telescope has revealed a significant population of high-redshift (z ~ 2) dust-obscured galaxies with large mid-infrared to ultraviolet luminosity ratios. Due to their optical faintness, these galaxies have been previously missed in traditional optical studies of the distant universe. We present a simple method for selecting this high-redshift population based solely on the ratio of the observed mid-infrared 24 μm to optical R-band flux density. We apply this method to observations of the ≈8.6 deg2 NOAO Deep Wide-Field Survey Boötes field, and uncover ≈2600 dust-obscured galaxy candidates [i.e., 0.089 arcmin-2) with 24 μm flux densities F24 μ m >= 0.3 mJy and (R - [ 24]) >= 14 (i.e., Fν(24 μ m)/Fν(R) gtrsim 1000]. These galaxies have no counterparts in the local universe. They represent 7% +/- 0.6% of the 24 μm source population at F24 μ m >= 1 mJy but increase to ≈13% +/- 1% of the population at ≈0.3 mJy. These galaxies exhibit evidence of both star formation and AGN activity, with the brighter 24 μm sources being more AGN-dominated. We have measured spectroscopic redshifts for 86 of these galaxies, and find a broad redshift distribution centered at \\overline{z}≈ 1.99+/- 0.05. The space density of this population is ΣDOG(F24μ m >= 0.3 mJy) = (2.82 +/- 0.05) × 10-5h370 Mpc -3, similar to that of bright submillimeter-selected galaxies at comparable redshifts. These redshifts imply large luminosities, with median ν Lν(8 μ m) ≈ 4 × 1011 L⊙. The infrared luminosity density contributed by this relatively rare dust-obscured galaxy population is log (IRLD) ≈ 8.23+ 0.18-0.30. This is ≈60+ 40-15% of that contributed by z ~ 2 ultraluminous infrared galaxies (ULIRGs, with LIR > 1012 L⊙) our simple selection thus identifies a significant fraction of z ~ 2 ULIRGs. This IRLD is ≈26% +/- 14% of the total contributed by all z ~ 2 galaxies. We suggest that these dust-obscured galaxies are the progenitors of luminous (~4L

  12. Whole-body MR angiography using variable density sampling and dual-injection bolus-chase acquisition.

    PubMed

    Du, Jiang; Korosec, Frank R; Wu, Yijing; Grist, Thomas M; Mistretta, Charles A

    2008-02-01

    Conventional bolus-chase acquisition generates peripheral runoff images using a single injection of the contrast material. Low spatial resolution, small slice coverage and venous contamination are major problems especially in the distal stations. A technique is presented herein in which whole-body magnetic resonance angiography is performed using a dual-contrast-injection four-station acquisition protocol. Bolus sharing was performed between two stations: the abdomen and calf stations share the first bolus injection, while the thorax and thigh stations share the second bolus injection. The combination of variable density sampling and elliptical centric acquisition order was applied to the abdomen and thorax stations. The scan time was extended to generate high spatial resolution arterial phase images with broad slice coverage for the calf and thigh stations. The feasibility of this technique was demonstrated using phantom and in vivo human volunteer studies.

  13. Novel capsules for potential theranostics of obscure gastrointestinal bleedings.

    PubMed

    Çolak, Bayram; Şakalak, Hüseyin; Çavuşoğlu, Halit; Yavuz, Mustafa Selman

    2016-09-01

    Obscure gastrointestinal (GI) bleeding is identified as persistent or repeated bleeding from the gastrointestinal tract which could not be defined by conventional gastrointestinal endoscopy and radiological examinations. These GI bleedings are assessed through invasive diagnostic and treatment methods including enteroscopy, angiography and endoscopy. In addition, video capsule endoscopy (VCE) is a non-invasive method used to determine the location of the bleeding, however, this does not provide any treatment. Despite of these successful but invasive methods, an effective non-invasive treatment is desperately needed. Herein, we prepare non-invasive theranostic capsules to cure obscure GI bleeding. An effective theranostic capsule containing endothelin as the targeting agent, thrombin-fibrinogen or fibrin as the treating agent, and fluorescein dye as the diagnostic tool is suggested. These theranostic capsules can be administered orally in a simple and non-invasive manner without a risk of complication. By using these novel capsules, one can diagnose obscure GI bleeding with having a possibility of curing. PMID:27515212

  14. Chase and NYANA: A Partnership To Remove Barriers to Job Performance 1993-94. Final Report.

    ERIC Educational Resources Information Center

    Auerbach, Charles

    A workplace literacy program implemented cooperatively by the New York Association for New Americans, Inc. (NYANA) and Chase Manhattan Bank is reported. The federally-funded project provided individualized communication workplace behavior and skills training in English as a Second Language for 30 limited-English-proficient bank employees working…

  15. 78 FR 69663 - Jonathan and Jayne Chase Troy Mills Hydroelectric Inc.; Notice of Transfer of Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-20

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Jonathan and Jayne Chase Troy Mills Hydroelectric Inc.; Notice of Transfer... exemption from licensing for the Troy Hydroelectric Project, FERC No. 13381, originally issued December...

  16. History Run Wild: The Alternate World of Joan Aiken's "The Wolves of Willoughby Chase" Series

    ERIC Educational Resources Information Center

    Dams, Isobel

    2005-01-01

    This article examines the historical fantasy world created by Joan Aiken in the eleven volumes of her "Wolves of Willoughby Chase" series. In particular it looks at her subversion of historical reality by the creation of an alternative yet recognisable representation of our own world, using a wide range of events, and the remoulding of aspects of…

  17. 78 FR 31839 - Establishment of Class E Airspace; Beeville-Chase Field, TX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-28

    ... page 18801, column 2, line 14, the title as published in the Federal Register of March 28, 2013 (78 FR 18801) FR Doc. 2013-06913, is corrected to read `` . . . Beeville-Chase Field, TX''; and on page 18802... Industrial Airport, Beeville, TX (78 FR 18801, March 28, 2013). Subsequent to publication, the FAA found...

  18. The Psychophysics of Chasing: A Case Study in the Perception of Animacy

    ERIC Educational Resources Information Center

    Gao, Tao; Newman, George E.; Scholl, Brian J.

    2009-01-01

    Psychologists have long been captivated by the perception of animacy--the fact that even simple moving shapes may appear to engage in animate, intentional, and goal-directed movements. Here we report several new types of studies of a particularly salient form of perceived animacy: "chasing", in which one shape (the "wolf") pursues another shape…

  19. Remembering Dr. George J. Apel, Jr: A Posthumous Tribute to an Innovative, Obscure Pioneer in Christian Higher Education

    ERIC Educational Resources Information Center

    Lumadue, Richard T.

    2007-01-01

    This paper is a belated tribute to George J. Apel, Jr., an innovative and obscure Christian higher educator. Peruse the name and subject indices of any and all books about Christian higher education, and nowhere will there appear even a reference to George J. Apel, Jr. Although Apel never finished high school or college, he was awarded an honorary…

  20. SR-71B - in Flight with F-18 Chase Aircraft - View from Air Force Tanker

    NASA Technical Reports Server (NTRS)

    1996-01-01

    NASA 831, an SR-71B operated by the Dryden Flight Research Center, Edwards, California, cruises over the Mojave Desert with an F/A-18 Hornet flying safety chase. They were photographed on a 1996 mission from an Air Force refueling tanker The F/A-18 Hornet is used primarily as a safety chase and support aircraft at Dryden. As support aircraft, the F-18s are used for safety chase, pilot proficiency and aerial photography. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used

  1. Hot Dust Obscured Galaxies with Excess Blue Light: Dual AGN or Single AGN Under Extreme Conditions?

    NASA Astrophysics Data System (ADS)

    Assef, R. J.; Walton, D. J.; Brightman, M.; Stern, D.; Alexander, D.; Bauer, F.; Blain, A. W.; Diaz-Santos, T.; Eisenhardt, P. R. M.; Finkelstein, S. L.; Hickox, R. C.; Tsai, C.-W.; Wu, J. W.

    2016-03-01

    Hot dust-obscured galaxies (Hot DOGs) are a population of hyper-luminous infrared galaxies identified by the Wide-field Infrared Survey Explorer (WISE) mission from their very red mid-IR colors, and characterized by hot dust temperatures (T > 60 K). Several studies have shown clear evidence that the IR emission in these objects is powered by a highly dust-obscured active galactic nucleus (AGN) that shows close to Compton-thick absorption at X-ray wavelengths. Thanks to the high AGN obscuration, the host galaxy is easily observable, and has UV/optical colors usually consistent with those of a normal galaxy. Here we discuss a sub-population of eight Hot DOGs that show enhanced rest-frame UV/optical emission. We discuss three scenarios that might explain the excess UV emission: (i) unobscured light leaked from the AGN by reflection over the dust or by partial coverage of the accretion disk; (ii) a second unobscured AGN in the system; or (iii) a luminous young starburst. X-ray observations can help discriminate between these scenarios. We study in detail the blue excess Hot DOG WISE J020446.13-050640.8, which was serendipitously observed by Chandra/ACIS-I for 174.5 ks. The X-ray spectrum is consistent with a single, hyper-luminous, highly absorbed AGN, and is strongly inconsistent with the presence of a secondary unobscured AGN. Based on this, we argue that the excess blue emission in this object is most likely either due to reflection or a co-eval starburst. We favor the reflection scenario as the unobscured star formation rate needed to power the UV/optical emission would be ≳1000 M⊙ yr-1. Deep polarimetry observations could confirm the reflection hypothesis.

  2. Similarity of ionized gas nebulae around unobscured and obscured quasars

    NASA Astrophysics Data System (ADS)

    Liu, Guilin; Zakamska, Nadia L.; Greene, Jenny E.

    2014-08-01

    Quasar feedback is suspected to play a key role in the evolution of massive galaxies, by removing or reheating gas in quasar host galaxies and thus limiting the amount of star formation. In this paper, we continue our investigation of quasar-driven winds on galaxy-wide scales. We conduct Gemini Integral Field Unit spectroscopy of a sample of luminous unobscured (type 1) quasars, to determine the morphology and kinematics of ionized gas around these objects, predominantly via observations of the [O III] λ5007 Å emission line. We find that ionized gas nebulae extend out to ˜13 kpc from the quasar, that they are smooth and round, and that their kinematics are inconsistent with gas in dynamical equilibrium with the host galaxy. The observed morphological and kinematic properties are strikingly similar to those of ionized gas around obscured (type 2) quasars with matched [O III] luminosity, with marginal evidence that nebulae around unobscured quasars are slightly more compact. Therefore, in samples of obscured and unobscured quasars carefully matched in [O III] luminosity, we find support for the standard geometry-based unification model of active galactic nuclei, in that the intrinsic properties of the quasars, of their hosts and of their ionized gas appear to be very similar. Given the apparent ubiquity of extended ionized regions, we are forced to conclude that either the quasar is at least partially illuminating pre-existing gas or that both samples of quasars are seen during advanced stages of quasar feedback. In the latter case, we may be biased by our [O III]-based selection against quasars in the early `blow-out' phase, for example due to dust obscuration.

  3. An Emerging Class of Extragalactic Self-Obscured Stars

    NASA Astrophysics Data System (ADS)

    Khan, Rubab M.

    2015-01-01

    The evolution of the most massive stars such as η Carinae is controlled by the effects of mass-loss. Understanding these stars is challenging because no true analogs of η Car have been clearly identified in the Milky Way or other galaxies. Copious mass-loss leads to circumstellar dust formation, obscuring the star in the optical. But as the light is re-emitted by the dust, these objects become very luminous in the mid-IR. We have carried out a systematic search for η Car analogs in 7 galaxies, utilizing data from Spitzer, Herschel, HST and other sources. Our search detected no true analogs of η Car, however, we do identify a significant population of 18 lower luminosity (log(L/L_⊙)≃5.5-6.0) dusty stars. Stars enter this phase at a rate that is a fraction 0.09 ≲ F ≲ 0.55 of the ccSN rate, and this is consistent with all 25 < M_{ZAMS} < 60M_⊙ stars undergoing an obscured phase at most lasting a few thousand years once or twice. These phases constitute a negligible fraction of post-main sequence lifetimes of massive stars, which implies that these events are likely to be associated with special periods in the evolution of the stars. The mass of the obscuring material is of order ˜ M_⊙, and we simply do not find enough heavily obscured stars for these phases to represent more than a modest fraction (˜ 10% not ˜ 50%) of the total mass lost by these stars. While this search has been feasible using archival Spitzer data, JWST will be a far more powerful probe of these stars. The HST-like resolution of JWST will either greatly reduce the problem of confusion or greatly expand the possible survey volume. Far more important will be the ability to carry out the survey at 24μm, which will increase the time over which dusty shells can be identified from hundreds of years to thousands of years, greatly improving the statistics and our ability to survey the long term evolution of these systems and the relationship between stellar eruptions and supernovae.

  4. Large scale obscuration and related climate effects open literature bibliography

    SciTech Connect

    Russell, N.A.; Geitgey, J.; Behl, Y.K.; Zak, B.D.

    1994-05-01

    Large scale obscuration and related climate effects of nuclear detonations first became a matter of concern in connection with the so-called ``Nuclear Winter Controversy`` in the early 1980`s. Since then, the world has changed. Nevertheless, concern remains about the atmospheric effects of nuclear detonations, but the source of concern has shifted. Now it focuses less on global, and more on regional effects and their resulting impacts on the performance of electro-optical and other defense-related systems. This bibliography reflects the modified interest.

  5. Large Scale Obscuration and Related Climate Effects Workshop: Proceedings

    SciTech Connect

    Zak, B.D.; Russell, N.A.; Church, H.W.; Einfeld, W.; Yoon, D.; Behl, Y.K.

    1994-05-01

    A Workshop on Large Scale Obsurcation and Related Climate Effects was held 29--31 January, 1992, in Albuquerque, New Mexico. The objectives of the workshop were: to determine through the use of expert judgement the current state of understanding of regional and global obscuration and related climate effects associated with nuclear weapons detonations; to estimate how large the uncertainties are in the parameters associated with these phenomena (given specific scenarios); to evaluate the impact of these uncertainties on obscuration predictions; and to develop an approach for the prioritization of further work on newly-available data sets to reduce the uncertainties. The workshop consisted of formal presentations by the 35 participants, and subsequent topical working sessions on: the source term; aerosol optical properties; atmospheric processes; and electro-optical systems performance and climatic impacts. Summaries of the conclusions reached in the working sessions are presented in the body of the report. Copies of the transparencies shown as part of each formal presentation are contained in the appendices (microfiche).

  6. Clustering of Dust-Obscured Galaxies at z ~ 2

    NASA Astrophysics Data System (ADS)

    Brodwin, Mark; Dey, Arjun; Brown, Michael J. I.; Pope, Alexandra; Armus, Lee; Bussmann, Shane; Desai, Vandana; Jannuzi, Buell T.; Le Floc'h, Emeric

    2008-11-01

    We present the angular autocorrelation function of 2603 dust-obscured galaxies (DOGs) in the Boötes field of the NOAO Deep Wide-Field Survey. DOGs are red, obscured galaxies, defined as having R - [ 24] >= 14 (F24/FRgtrsim 1000). Spectroscopy indicates that they are located at 1.5 lesssim z lesssim 2.5. We find strong clustering, with r0 = 7.40-0.84+1.27 h-1 Mpc for the full F24 > 0.3 mJy sample. The clustering and space density of the DOGs are consistent with those of submillimeter galaxies, suggestive of a connection between these populations. We find evidence for luminosity-dependent clustering, with the correlation length increasing to r0 = 12.97-2.64+4.26 h-1 Mpc for brighter (F24 > 0.6 mJy) DOGs. Bright DOGs also reside in richer environments than fainter ones, suggesting these subsamples may not be drawn from the same parent population. The clustering amplitudes imply average halo masses of log M = 12.2-0.2+0.3 M⊙ for the full DOG sample, rising to log M = 13.0-0.3+0.4 M⊙ for brighter DOGs. In a biased structure formation scenario, the full DOG sample will, on average, evolve into ~3L* present-day galaxies, whereas the most luminous DOGs may evolve into brightest cluster galaxies.

  7. Hierarchical human action recognition around sleeping using obscured posture information

    NASA Astrophysics Data System (ADS)

    Kudo, Yuta; Sashida, Takehiko; Aoki, Yoshimitsu

    2015-04-01

    This paper presents a new approach for human action recognition around sleeping with the human body parts locations and the positional relationship between human and sleeping environment. Body parts are estimated from the depth image obtained by a time-of-flight (TOF) sensor using oriented 3D normal vector. Issues in action recognition of sleeping situation are the demand of availability in darkness, and hiding of the human body by duvets. Therefore, the extraction of image features is difficult since color and edge features are obscured by covers. Thus, first in our method, positions of four parts of the body (head, torso, thigh, and lower leg) are estimated by using the shape model of bodily surface constructed by oriented 3D normal vector. This shape model can represent the surface shape of rough body, and is effective in robust posture estimation of the body hidden with duvets. Then, action descriptor is extracted from the position of each body part. The descriptor includes temporal variation of each part of the body and spatial vector of position of the parts and the bed. Furthermore, this paper proposes hierarchical action classes and classifiers to improve the indistinct action classification. Classifiers are composed of two layers, and recognize human action by using the action descriptor. First layer focuses on spatial descriptor and classifies action roughly. Second layer focuses on temporal descriptor and classifies action finely. This approach achieves a robust recognition of obscured human by using the posture information and the hierarchical action recognition.

  8. Obscured Asymptotic Giant Branch Stars in the Magellanic Clouds

    NASA Astrophysics Data System (ADS)

    van Loon, J. T.

    The most drastic change in the life of an intermediate mass star occurs when it approaches the tip of the Asymptotic Giant Branch (AGB). Large amplitude pulsation of the stellar photosphere and favourable conditions for dust formation cause these stars to develop heavy mass loss, leading to the star's death. The dusty circumstellar envelope (CSE) obscures the optical light from the star and re-emits at longer wavelengths, making it a very bright infrared (IR) object. The physical mechanism of the mass loss and its temporal behaviour are not understood. AGB stars can be best studied in either of the Magellanic Clouds, as these stars are all at nearly the same, well known distance to us, and suffer relatively little interstellar extinction. The Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) have metallicities a factor ~ 2 and 5 lower than the Milky Way, hence the metallicity dependence of the evolution and mass loss of AGB stars can be studied. A significant number of obscured AGB stars have been found in the Magellanic Clouds only very recently (Loup et al. 1997; Zijlstra et al. 1996; van Loon et al. 1997, 1998a; Groenewegen and Blommaert 1998). I first briefly describe our searches for AGB stars as counterparts of IRAS point sources in the Magellanic Clouds, using near-IR photometers and arrays. IR spectrophotometry and spectroscopy from the ground and from space (IRAS and ISO) are used to classify the stars as oxygen or carbon rich AGB stars. Both oxygen and carbon stars can be found at all luminosities from 6,000 to 40,000 Lo. Luminous carbon stars are the result of a reduced envelope mass due to mass loss, switching off Hot Bottom Burning. Near-IR monitoring has resulted in known periods and amplitudes for the obscured AGB stars in the Large Magellanic Cloud. The period-luminosity diagram of these Long Period Variables (LPVs) indicates the occurrence of thermal pulses. I show that the reddest stars, with the optically thickest CSEs, are not the

  9. Obscuration effects in super-soft-source X-ray spectra

    NASA Astrophysics Data System (ADS)

    Ness, J.-U.; Osborne, J. P.; Henze, M.; Dobrotka, A.; Drake, J. J.; Ribeiro, V. A. R. M.; Starrfield, S.; Kuulkers, E.; Behar, E.; Hernanz, M.; Schwarz, G.; Page, K. L.; Beardmore, A. P.; Bode, M. F.

    2013-11-01

    Context. Super-soft-source (SSS) X-ray spectra are blackbody-like spectra with effective temperatures ~3-7 × 105 K and luminosities of 1035-38 erg s-1. Grating spectra of SSS and novae in outburst that show SSS type spectra display atmospheric absorption lines. Radiation transport atmosphere models can be used to derive physical parameters. Blue-shifted absorption lines suggest that hydrostatic equilibrium is an insufficient assumption, and more sophisticated models are required. Aims: In this paper, we bypass the complications of spectral models and concentrate on the data in a comparative, qualitative study. We inspect all available X-ray grating SSS spectra to determine systematic, model-independent trends. Methods: We collected all grating spectra of conventional SSS like Cal 83 and Cal 87 plus observations of novae during their SSS phase. We used comparative plots of spectra of different systems to find common and different features. The results were interpreted in the context of system parameters obtained from the literature. Results: We find two distinct types of SSS spectra that we name SSa and SSe. Their main observational characteristics are either clearly visible absorption lines or emission lines, respectively, while both types contain atmospheric continuum emission. SSa spectra are highly structured with no spectral model currently able to reproduce all details. The emission lines clearly seen in SSe may also be present in SSa, hidden within the forest of complex atmospheric absorption and emission features. This suggests that SSe are in fact obscured SSa systems. Similarities between SSe and SSa with obscured and unobscured AGN, respectively, support this interpretation. We find all known or suspected high-inclination systems to emit permanently in an SSe state. Some sources are found to transition between SSa and SSe states, becoming SSe when fainter. Conclusions: SSS spectra are subject to various occultation processes. In persistent SSS spectra

  10. Inner disc obscuration in GRS 1915+105 based on relativistic slim disc model

    NASA Astrophysics Data System (ADS)

    Vierdayanti, K.; Sadowski, A.; Mineshige, S.; Bursa, M.

    2013-11-01

    We study the observational signatures of the relativistic slim disc of 10 M⊙ black hole, in a wide range of mass accretion rate, dot{m}, dimensionless spin parameter, a*, and viewing angle, i. In general, the innermost temperature, Tin, increases with the increase of i for a fixed value of dot{m} and a*, due to the Doppler effect. However, for i > 50° and dot{m}>dot{m}_turn, Tin starts to decrease with the increase of dot{m}. This is a result of self-obscuration - the radiation from the innermost hot part of the disc is blocked by the surrounding cooler part. The value of dot{m}_turn and the corresponding luminosities depend on a* and i. Such obscuration effects cause an interesting behaviour on the disc luminosity (Ldisc)-Tin plane for high inclinations. In addition to the standard disc branch which appears below dot{m}_turn and which obeys L_disc ∝ T_in4 relation, another branch above dot{m}_turn, which is nearly horizontal, may be observed at luminosities close to the Eddington luminosity. We show that these features are likely observed in a Galactic X-ray source, GRS 1915+105. We support a high spin parameter (a* > 0.9) for GRS 1915+105 since otherwise the high value of Tin and small size of the emitting region (rin < 1rS) cannot be explained.

  11. Probing dust-obscured star formation in the most massive gamma-ray burst host galaxies

    NASA Astrophysics Data System (ADS)

    Greiner, Jochen; Michałowski, Michał J.; Klose, Sylvio; Hunt, Leslie K.; Gentile, Gianfranco; Kamphuis, Peter; Herrero-Illana, Rubén; Wieringa, Mark; Krühler, Thomas; Schady, Patricia; Elliott, Jonathan; Graham, John F.; Ibar, Eduardo; Knust, Fabian; Nicuesa Guelbenzu, Ana; Palazzi, Eliana; Rossi, Andrea; Savaglio, Sandra

    2016-08-01

    Context. As a result of their relation to massive stars, long-duration gamma-ray bursts (GRBs) allow the pinpointing of star formation in galaxies independent of redshift, dust obscuration, or galaxy mass/size, thus providing a unique tool to investigate star formation history over cosmic time. Aims: About half of the optical afterglows of long-duration GRBs are missed owing to dust extinction and are primarily located in the most massive GRB hosts. It is important to investigate the amount of obscured star formation in these GRB host galaxies to understand this bias. Methods: Radio emission of galaxies correlates with star formation, but does not suffer extinction as do the optical star formation estimators. We selected 11 GRB host galaxies with either large stellar mass or large UV-based and optical-based star formation rates (SFRs) and obtained radio observations of these with the Australia Telescope Compact Array and the Karl Jansky Very Large Array. Results: Despite intentionally selecting GRB hosts with expected high SFRs, we do not find any radio emission related to star formation in any of our targets. Our upper limit for GRB 100621A implies that the earlier reported radio detection was due to afterglow emission. We detect radio emission from the position of GRB 020819B, but argue that it is in large part, if not completely, due to afterglow contamination. Conclusions: Half of our sample has radio-derived SFR limits, which are only a factor 2-3 above the optically measured SFRs. This supports other recent studies that the majority of star formation in GRB hosts is not obscured by dust. Based on observations collected with ATCA under ID C2718, and at VLA under ID 13B-017.

  12. Cheetahs, Acinonyx jubatus, balance turn capacity with pace when chasing prey.

    PubMed

    Wilson, John W; Mills, Michael G L; Wilson, Rory P; Peters, Gerrit; Mills, Margaret E J; Speakman, John R; Durant, Sarah M; Bennett, Nigel C; Marks, Nikki J; Scantlebury, Michael

    2013-10-23

    Predator-prey interactions are fundamental in the evolution and structure of ecological communities. Our understanding, however, of the strategies used in pursuit and evasion remains limited. Here, we report on the hunting dynamics of the world's fastest land animal, the cheetah, Acinonyx jubatus. Using miniaturized data loggers, we recorded fine-scale movement, speed and acceleration of free-ranging cheetahs to measure how hunting dynamics relate to chasing different sized prey. Cheetahs attained hunting speeds of up to 18.94 m s(-1) and accelerated up to 7.5 m s(-2) with greatest angular velocities achieved during the terminal phase of the hunt. The interplay between forward and lateral acceleration during chases showed that the total forces involved in speed changes and turning were approximately constant over time but varied with prey type. Thus, rather than a simple maximum speed chase, cheetahs first accelerate to decrease the distance to their prey, before reducing speed 5-8 s from the end of the hunt, so as to facilitate rapid turns to match prey escape tactics, varying the precise strategy according to prey species. Predator and prey thus pit a fine balance of speed against manoeuvring capability in a race for survival.

  13. Cheetahs, Acinonyx jubatus, balance turn capacity with pace when chasing prey

    PubMed Central

    Wilson, John W.; Mills, Michael G. L.; Wilson, Rory P.; Peters, Gerrit; Mills, Margaret E. J.; Speakman, John R.; Durant, Sarah M.; Bennett, Nigel C.; Marks, Nikki J.; Scantlebury, Michael

    2013-01-01

    Predator–prey interactions are fundamental in the evolution and structure of ecological communities. Our understanding, however, of the strategies used in pursuit and evasion remains limited. Here, we report on the hunting dynamics of the world's fastest land animal, the cheetah, Acinonyx jubatus. Using miniaturized data loggers, we recorded fine-scale movement, speed and acceleration of free-ranging cheetahs to measure how hunting dynamics relate to chasing different sized prey. Cheetahs attained hunting speeds of up to 18.94 m s−1 and accelerated up to 7.5 m s−2 with greatest angular velocities achieved during the terminal phase of the hunt. The interplay between forward and lateral acceleration during chases showed that the total forces involved in speed changes and turning were approximately constant over time but varied with prey type. Thus, rather than a simple maximum speed chase, cheetahs first accelerate to decrease the distance to their prey, before reducing speed 5–8 s from the end of the hunt, so as to facilitate rapid turns to match prey escape tactics, varying the precise strategy according to prey species. Predator and prey thus pit a fine balance of speed against manoeuvring capability in a race for survival. PMID:24004493

  14. Cheetahs, Acinonyx jubatus, balance turn capacity with pace when chasing prey.

    PubMed

    Wilson, John W; Mills, Michael G L; Wilson, Rory P; Peters, Gerrit; Mills, Margaret E J; Speakman, John R; Durant, Sarah M; Bennett, Nigel C; Marks, Nikki J; Scantlebury, Michael

    2013-10-23

    Predator-prey interactions are fundamental in the evolution and structure of ecological communities. Our understanding, however, of the strategies used in pursuit and evasion remains limited. Here, we report on the hunting dynamics of the world's fastest land animal, the cheetah, Acinonyx jubatus. Using miniaturized data loggers, we recorded fine-scale movement, speed and acceleration of free-ranging cheetahs to measure how hunting dynamics relate to chasing different sized prey. Cheetahs attained hunting speeds of up to 18.94 m s(-1) and accelerated up to 7.5 m s(-2) with greatest angular velocities achieved during the terminal phase of the hunt. The interplay between forward and lateral acceleration during chases showed that the total forces involved in speed changes and turning were approximately constant over time but varied with prey type. Thus, rather than a simple maximum speed chase, cheetahs first accelerate to decrease the distance to their prey, before reducing speed 5-8 s from the end of the hunt, so as to facilitate rapid turns to match prey escape tactics, varying the precise strategy according to prey species. Predator and prey thus pit a fine balance of speed against manoeuvring capability in a race for survival. PMID:24004493

  15. The origins of active galactic nuclei obscuration: the 'torus' as a dynamical, unstable driver of accretion

    NASA Astrophysics Data System (ADS)

    Hopkins, Philip F.; Hayward, Christopher C.; Narayanan, Desika; Hernquist, Lars

    2012-02-01

    Recent multiscale simulations have made it possible to follow gas inflows responsible for high-Eddington ratio accretion on to massive black holes (BHs) from galactic scales to the BH accretion disc. When sufficient gas is driven towards a BH, gravitational instabilities generically form lopsided, eccentric discs that propagate inwards from larger radii. The lopsided stellar disc exerts a strong torque on the gas, driving inflows that fuel the growth of the BH. Here, we investigate the possibility that the same disc, in its gas-rich phase, is the putative 'torus' invoked to explain obscured active galactic nuclei (AGN) and the cosmic X-ray background. The disc is generically thick and has characteristic ˜1-10 pc sizes and masses resembling those required of the torus. Interestingly, the scale heights and obscured fractions of the predicted torii are substantial even in the absence of strong stellar feedback providing the vertical support. Rather, they can be maintained by strong bending modes and warps/twists excited by the inflow-generating instabilities. A number of other observed properties commonly attributed to 'feedback' processes may in fact be explained entirely by dynamical, gravitational effects: the lack of alignment between torus and host galaxy, correlations between local star formation rate (SFR) and turbulent gas velocities and the dependence of obscured fractions on AGN luminosity or SFR. We compare the predicted torus properties with observations of gas surface density profiles, kinematics, scale heights and SFR densities in AGN, and find that they are consistent in all cases. We argue that it is not possible to reproduce these observations and the observed column density distribution without a clumpy gas distribution, but allowing for simple clumping on small scales the predicted column density distribution is in good agreement with observations from NH˜ 1020-1027 cm-2. We examine how the NH distribution scales with galaxy and AGN properties

  16. On suffering and sympathy: "Jude the Obscure," evolution, and ethics.

    PubMed

    Sumpter, Caroline

    2011-01-01

    This article links Thomas Hardy's exploration of sympathy in "Jude the Obscure" to contemporary scientific debates over moral evolution. Tracing the relationship between pessimism, progressivism, and determinism in Hardy's understanding of sympathy, it also considers Hardy's conception of the author as enlarger of 'social sympathies' - a position, I argue, that was shaped by Leslie Stephen's advocacy of novel writing as moral art. Considering Hardy's engagement with writings by Charles Darwin, T.H. Huxley, Herbert Spencer, and others, I explore the novel's participation in a debate about the evolutionary significance of sympathy and its implications for Hardy's understanding of moral agency. Hardy, I suggest, offered a stronger defence of morality based on biological determinism than Darwin, but this determinism was linked to an unexpected evolutionary optimism. PMID:22355828

  17. A Lip Extraction Algorithm by Using Color Information Considering Obscurity

    NASA Astrophysics Data System (ADS)

    Shirasawa, Yoichi; Nishida, Makoto

    This paper proposes a method for extracting lip shape and its location from sequential facial images by using color information. The proposed method has no need of extra information on a position nor a form in advance. It is also carried out without special conditions such as lipstick or lighting. Psychometric quantities of a metric hue angle, a metric hue difference and a rectangular coordinates, which are defined in CIE 1976 L*a*b* color space, are used for the extraction. The method employs fuzzy reasoning in order to consider obscurity in image data such as shade on the face. The experimental result indicate the effectiveness of the proposed method; 100 percent of facial images data was estimated a lip’s position, and about 94 percent of facial images data was extracted its shape.

  18. On suffering and sympathy: "Jude the Obscure," evolution, and ethics.

    PubMed

    Sumpter, Caroline

    2011-01-01

    This article links Thomas Hardy's exploration of sympathy in "Jude the Obscure" to contemporary scientific debates over moral evolution. Tracing the relationship between pessimism, progressivism, and determinism in Hardy's understanding of sympathy, it also considers Hardy's conception of the author as enlarger of 'social sympathies' - a position, I argue, that was shaped by Leslie Stephen's advocacy of novel writing as moral art. Considering Hardy's engagement with writings by Charles Darwin, T.H. Huxley, Herbert Spencer, and others, I explore the novel's participation in a debate about the evolutionary significance of sympathy and its implications for Hardy's understanding of moral agency. Hardy, I suggest, offered a stronger defence of morality based on biological determinism than Darwin, but this determinism was linked to an unexpected evolutionary optimism.

  19. Necrotizing sialometaplasia obscuring an underlying malignancy: report of a case.

    PubMed

    Poulson, T C; Greer, R O; Ryser, R W

    1986-07-01

    Necrotizing sialometaplasia poses many diagnostic problems, both clinically and microscopically. Caution had most frequently been urged for distinguishing between malignancy and NS, so as to avoid mutilating surgical treatment resulting from the misdiagnosis of a lesion that is benign and self-limiting. This case has been presented to alert the practitioner to the possibility that NS may obscure an underlying malignant disease process, possibly resulting in delays in referral or treatment. The exceedingly rapid growth of this mesenchymal neoplasm may have caused obstruction of the blood supply to the overlying mucosa and submucosa, thereby producing the ischemic alterations observed in the first biopsy specimens. Some of the difficulties encountered in the detection and diagnosis of neoplasms arising in the parapharyngeal space were discussed, and some previously published suggestions to aid in these efforts were reiterated.

  20. A NICMOS search for obscured supernovae in starburst galaxies

    NASA Astrophysics Data System (ADS)

    Cresci, G.; Mannucci, F.; Della Valle, M.; Maiolino, R.

    2007-02-01

    The detection of obscured supernovae (SNe) in near-infrared monitoring campaigns of starburst galaxies has shown that a significant fraction of SNe is missed by optical surveys. However, the number of SNe detected in ground-based near-IR observations is still significantly lower than the number of SNe extrapolated from the FIR luminosity of the hosts. A possibility is that most SNe occur within the nuclear regions, where the limited angular resolution of ground-based observations prevents their detection. This issue prompted us to exploit the superior angular resolution of NICMOS-HST to search for obscured SNe within the first kpc from the nucleus of strong starbursting galaxies. A total of 17 galaxies were observed in SNAPSHOT mode. Based on their FIR luminosity, we did not expect to detect fewer than ~ 12 SNe. However, no confirmed SN event was found. From our data we derived an observed nuclear SN rate <0.5 SN/yr per galaxy. The shortage of SN detections can be explained by a combination of several effects. The most important are: i) the existence of a strong extinction, A_V⪆ 11; ii) most SNe occur within the first 0.5 arcsec (which corresponds in our sample to about 500 pc) where even NICMOS is unable to detect SN events. Based on observations made with the NASA/ESA Hubble Space Telescope associated with program 9726, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555, and on data obtained at the VLT through the ESO program 272.D-5043.

  1. Obscuring ecosystem function with application of the ecosystem services concept.

    PubMed

    Peterson, Markus J; Hall, Damon M; Feldpausch-Parker, Andrea M; Peterson, Tarla Rai

    2010-02-01

    Conservationists commonly have framed ecological concerns in economic terms to garner political support for conservation and to increase public interest in preserving global biodiversity. Beginning in the early 1980s, conservation biologists adapted neoliberal economics to reframe ecosystem functions and related biodiversity as ecosystem services to humanity. Despite the economic success of programs such as the Catskill/Delaware watershed management plan in the United States and the creation of global carbon exchanges, today's marketplace often fails to adequately protect biodiversity. We used a Marxist critique to explain one reason for this failure and to suggest a possible, if partial, response. Reframing ecosystem functions as economic services does not address the political problem of commodification. Just as it obscures the labor of human workers, commodification obscures the importance of the biota (ecosystem workers) and related abiotic factors that contribute to ecosystem functions. This erasure of work done by ecosystems impedes public understanding of biodiversity. Odum and Odum's radical suggestion to use the language of ecosystems (i.e., emergy or energy memory) to describe economies, rather than using the language of economics (i.e., services) to describe ecosystems, reverses this erasure of the ecosystem worker. Considering the current dominance of economic forces, however, implementing such solutions would require social changes similar in magnitude to those that occurred during the 1960s. Niklas Luhmann argues that such substantive, yet rapid, social change requires synergy among multiple societal function systems (i.e., economy, education, law, politics, religion, science), rather than reliance on a single social sphere, such as the economy. Explicitly presenting ecosystem services as discreet and incomplete aspects of ecosystem functions not only allows potential economic and environmental benefits associated with ecosystem services, but also

  2. The Nature of Soft X-ray Emission in Obscured AGN

    NASA Astrophysics Data System (ADS)

    Guainazzi, M.

    2006-08-01

    We present results of a high-resolution soft X-ray (0.2 - 2 keV) spectroscopic study on a sample of 66 nearby obscured AGN observed by the Reflection Grating Spectrometer (RGS) on board XMM-Newton. This is the largest sample ever studied with this technique so far. The main conclusions of our study can be summarized as follows: a) narrow Radiative Recombination Continua are detected in 40% of the objects in our sample; in 27% their width is ≤ 10 eV; b) higher order transitions are generally enhanced with respect to pure photoionization, indicating that resonant scattering plays an important role in the ionization/excitation balance. These results support the scenario whereby the active nucleus is responsible for the X-ray 'soft excess' almost ubiquitously observed in nearby obscured AGN via photoionization of circumnuclear gas. They confirm on a statistical basis the conclusions drawn from the detailed study of the brightest spectra in the sample. Furthermore, we propose a criterion to statistically discriminate between AGN-photoionized sources and starbursts galaxies, based on intensity of the forbidden component of the OVII He-alpha triplet (once normalized to the OVIII Ly-alpha) coupled with the integrated luminosity in He-like and H-like oxygen lines.

  3. Dust Properties of Local Dust-obscured Galaxies with the Submillimeter Array

    NASA Astrophysics Data System (ADS)

    Hwang, Ho Seong; Andrews, Sean M.; Geller, Margaret J.

    2013-11-01

    We report Submillimeter Array observations of the 880 μm dust continuum emission for four dust-obscured galaxies (DOGs) in the local universe. Two DOGs are clearly detected with S ν(880 μm) =10-13 mJy and S/N > 5, but the other two are not detected with 3σ upper limits of S ν(880 μm) =5-9 mJy. Including an additional two local DOGs with submillimeter data from the literature, we determine the dust masses and temperatures for six local DOGs. The infrared luminosities and dust masses for these DOGs are in the ranges of 1.2-4.9 × 1011(L ⊙) and 4-14 × 107(M ⊙), respectively. The dust temperatures derived from a two-component modified blackbody function are 23-26 K and 60-124 K for the cold and warm dust components, respectively. Comparison of local DOGs with other infrared luminous galaxies with submillimeter detections shows that the dust temperatures and masses do not differ significantly among these objects. Thus, as argued previously, local DOGs are not a distinctive population among dusty galaxies, but simply represent the high-end tail of the dust obscuration distribution.

  4. The Obscuring Starburst of NGC 6221 and Implications for the Hard X-Ray Background

    NASA Technical Reports Server (NTRS)

    Levenson, N. A.; CidFernandes, R., Jr.; Weaver, K. A.; Heckman, T. M.; Storchi-Bergmann, T.; White, Nicholas E. (Technical Monitor)

    2001-01-01

    We present NGC 6221 as a case study of "X-ray-loud composite galaxies," which appear similar to starbursts at optical wavelengths and resemble traditional active galactic nuclei in X-rays. The net optical spectrum of NGC 6221 is properly characterized as a starburst galaxy, but in X-rays, NGC 6221 is similar to Seyfert 1 galaxies, exhibiting a power-law continuum spectrum, a broad Fe K(alpha) line, and continuum variability on timescales of days and years. High-resolution images reveal that the detected active nucleus is relatively weak, not only at optical, but also at near-infrared wavelengths. An obscuring starburst, in which the interstellar gas and dust associated with the starburst conceal the active nucleus, accounts for these peculiar features. We demonstrate quantitatively that obscuration by column density N(sub H) = 10(exp 22)/sq cm combined with relatively weak intrinsic nuclear activity can produce an optical spectrum that is characteristic of the surrounding starburst alone. While optical surveys would not identify the active nuclei that make these galaxies significant X-ray sources, such galaxies may, in fact, be important contributors to the X-ray background.

  5. DUST PROPERTIES OF LOCAL DUST-OBSCURED GALAXIES WITH THE SUBMILLIMETER ARRAY

    SciTech Connect

    Hwang, Ho Seong; Andrews, Sean M.; Geller, Margaret J. E-mail: sandrews@cfa.harvard.edu

    2013-11-01

    We report Submillimeter Array observations of the 880 μm dust continuum emission for four dust-obscured galaxies (DOGs) in the local universe. Two DOGs are clearly detected with S{sub ν}(880 μm) =10-13 mJy and S/N > 5, but the other two are not detected with 3σ upper limits of S{sub ν}(880 μm) =5-9 mJy. Including an additional two local DOGs with submillimeter data from the literature, we determine the dust masses and temperatures for six local DOGs. The infrared luminosities and dust masses for these DOGs are in the ranges of 1.2-4.9 × 10{sup 11}(L{sub ☉}) and 4-14 × 10{sup 7}(M{sub ☉}), respectively. The dust temperatures derived from a two-component modified blackbody function are 23-26 K and 60-124 K for the cold and warm dust components, respectively. Comparison of local DOGs with other infrared luminous galaxies with submillimeter detections shows that the dust temperatures and masses do not differ significantly among these objects. Thus, as argued previously, local DOGs are not a distinctive population among dusty galaxies, but simply represent the high-end tail of the dust obscuration distribution.

  6. Fraunhofer diffraction patterns from uniformly illuminated square output apertures with noncentered square obscurations.

    PubMed

    Sutton, G W; Weiner, M M; Mani, S A

    1976-09-01

    Theoretical Fraunhofer diffraction patterns are presented for uniformly illuminated square apertures with noncentered square obscurations. The energy within a given subtended solid angle in the far field is calculated. It is shown that the cornered-off-axis obscuration provides much more far-field energy in a given spot size than the centered obscuration for the same clear aperture area and total energy, for example, 82% more far-field energy in the first Airy square for 50% obscuration, thus providing superior performance for practical systems.

  7. A COMPARISON OF X-RAY AND MID-INFRARED SELECTION OF OBSCURED ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Eckart, Megan E.; Harrison, Fiona A.; McGreer, Ian D.; Helfand, David J.; Stern, Daniel

    2010-01-01

    We compare the relative merits of active galactic nuclei (AGNs) selection at X-ray and mid-infrared wavelengths using data from moderately deep fields observed by both Chandra and Spitzer. The X-ray-selected AGN sample and associated photometric and spectroscopic optical follow-up are drawn from a subset of fields studied as part of the Serendipitous Extragalactic X-ray Source Identification (SEXSI) program. Mid-infrared data in these fields are derived from targeted and archival Spitzer imaging, and mid-infrared AGN selection is accomplished primarily through application of the Infrared Array Camera (IRAC) color-color AGN 'wedge' selection technique. Nearly all X-ray sources in these fields which exhibit clear spectroscopic signatures of AGN activity have mid-infrared colors consistent with IRAC AGN selection. These are predominantly the most luminous X-ray sources. X-ray sources that lack high-ionization and/or broad lines in their optical spectra are far less likely to be selected as AGNs by mid-infrared color selection techniques. The fraction of X-ray sources identified as AGNs in the mid-infrared increases monotonically as the X-ray luminosity increases. Conversely, only 22% of mid-infrared-selected AGNs are detected at X-ray energies in the moderately deep ((t{sub exp}) approx 100 ks) SEXSI Chandra data. We hypothesize that IRAC sources with AGN colors that lack X-ray detections are predominantly high-luminosity AGNs that are obscured and/or lie at high redshift. A stacking analysis of X-ray-undetected sources shows that objects in the mid-infrared AGN selection wedge have average X-ray fluxes in the 2-8 keV band 3 times higher than sources that fall outside the wedge. Their X-ray spectra are also harder. The hardness ratio of the wedge-selected stack is consistent with moderate intrinsic obscuration, but is not suggestive of a highly obscured, Compton-thick source population. It is evident from this comparative study that in order to create a complete

  8. Four Asteroids and a Question Mark: Chasing Ross' Variables

    NASA Astrophysics Data System (ADS)

    Bedient, James

    2004-06-01

    F. E. Ross published a series of papers in 1925-1931 listing 379 new variable stars discovered during his search for high-proper-motion stars. In the years since then 271 have been studied and catalogued in the General Catalogue of Variable Stars. This paper identifies four of the remainder as asteroids, and discusses interesting observations of another.

  9. Chasing the College Dream in Hard Economic Times. Issue Brief

    ERIC Educational Resources Information Center

    Buddin, Richard; Croft, Michelle

    2014-01-01

    Slow economic growth in the past several years has strained the financial resources of many American families and heightened financial burdens for families hoping to support their children's college education. These economic struggles come at a critical time for high school students who rely on family resources to fund large portions of college…

  10. In the Dusty Recesses: Characterizing the Dark Matter Halos of Obscured Quasars via Clustering and CMB Lensing

    NASA Astrophysics Data System (ADS)

    Myers, Adam D.; DiPompeo, Michael A.; Hickox, Ryan C.; Runnoe, Jessie C.

    2016-06-01

    The spatial clustering of obscured and unobscured quasars provides an interesting constraint on the connection between the growth of supermassive black holes and the evolution of galaxies and large-scale structure. In pursuit of these constraints, we update our recent measurements of quasar clustering using WISE and Planck data. We carefully assess how alterations in these missions' data reduction pipelines result in different systematics on a range of angular scales, and define samples of WISE-selected quasars that appear to be least-influenced by differences in data calibration. With these samples we analyze quasar clustering via two complementary methods; the angular autocorrelation function and cosmic microwave background lensing cross-correlations. We measure a higher bias and halo mass for obscured quasars (b ~ 2.1) as compared to unobscured quasars (b ~ 1.8). This is at odds with simple orientation models but at a reduced significance (1.5σ) as compared to our work with previous survey data. Assuming that some fraction (as high as 75%) of obscured quasars are intrinsically similar to unobscured quasars but viewed through a "dusty torus," we infer that the remaining non-torus obscured quasar population must have a large clustering bias of ~3, and inhabit typical halo masses of ~3 × 1013 h-1M⊙ at a redshift of z ~ 1. These massive halos are likely the descendants of high-mass unobscured quasars at high redshift, and will evolve into members of galaxy groups by z ~ 0. This work was supported in part by NSF grants 1211112, 1515404 and 1515364.

  11. Aeromag interpretation technology helps chase Cambrian in New York

    SciTech Connect

    Fagan, J.P. Jr.; Copley, D.L.

    1998-02-16

    Building a geologic model from the bottom up, Ardent Resources Inc. conducted a high-sensitivity, high-resolution aeromagnetic survey in western New York. The aeromagnetic survey was flown to delineate deep-seated structural patterns which affected emplacement of Cambrian oil and gas reservoirs. In an effort to extend the Rose Run play into western New York, Ardent employed Pearson, deRidder and Johnson Inc. (PRJ) to acquire, process, and interpret an aeromagnetic survey covering about 170,000 acres. An exploratory well drilled upon the interpretation results of the survey is an indicated gas discovery in the Rose run equivalent upper Cambrian Theresa formation. The paper describes the geologic rationale, an integrated study, and future developments.

  12. Chaotic component obscured by strong periodicity in voice production system

    PubMed Central

    Tao, Chao; Jiang, Jack J.

    2010-01-01

    The effect of glottal aerodynamics in producing the nonlinear characteristics of voice is investigated by comparing the outputs of the asymmetric composite model and the two-mass model. The two-mass model assumes the glottal airflow to be laminar, nonviscous, and incompressible. In this model, when the asymmetric factor is decreased from 0.65 to 0.35, only 1:1 and 1:2 modes are detectable. However, with the same parameters, four vibratory modes (1:1, 1:2, 2:4, 2:6) are found in the asymmetric composite model using the Navier-Stokes equations to describe the complex aerodynamics in the glottis. Moreover, the amplitude of the waveform is modulated by a small-amplitude noiselike series. The nonlinear detection method reveals that this noiselike modulation is not random, but rather it is deterministic chaos. This result agrees with the phenomenon often seen in voice, in which the voice signal is strongly periodic but modulated by a small-amplitude chaotic component. The only difference between the two-mass model and the composite model is in their descriptions of glottal airflow. Therefore, the complex aerodynamic characteristics of glottal airflow could be important in generating the nonlinear dynamic behavior of voice production, including bifurcation and a small-amplitude chaotic component obscured by strong periodicity. PMID:18643315

  13. Studying AGN Feedback with Galactic Outflows in Luminous Obscured Quasar

    NASA Astrophysics Data System (ADS)

    Sun, Ai-Lei

    2016-01-01

    Feedback from Active galactic nuclei (AGN) has been proposed as an important quenching mechanism to suppress star formation in massive galaxies. We investigate the most direct form of AGN feedback - galactic outflows - in the most luminous obscured AGN (L>10^45 erg/s) from the SDSS sample in the nearby universe (z<0.2). Using ALMA and Magellan observations to target molecular and ionized outflows, we find that luminous AGN can impact the dynamics and phase of the galactic medium, and confirm the complex multi-phase and multi-scaled nature of the feedback phenomenon. In particular, we found that most of these luminous AGN hosts ionized outflows. The outflow size, velocity, and energetics correlate with the AGN luminosity, and can be very extended (r > 10 kpc) and fast (v > 1000 km/s) for the most luminous ones. I end with presenting a new technique to find extended ionized outflows using broadband imaging surveys, and to characterize their occurrence rate, morphology, size distribution, and their dependence on the AGN luminosity. This technique will open a new window for feedback studies in the era of large-scale optical imaging surveys, e.g., HSC and then LSST.

  14. The COSPIX Mission: Focusing on the Energetic and Obscured Universe

    NASA Technical Reports Server (NTRS)

    Ferrando, P.; Goldwurm, A.; Laurent, P.; Limousin, O.; Beckmann, V; Arnaud, M.; Barcons, X.; Bomans, D.; Caballero, I.; Carrera, F.; Chaty, S.; Chenevez, J.; Claret, A.; Corbel, S.; Croston, J.; Daddi, E.; De Becker, M.; Decourchelle, A.; Elbaz, D.; Falanga, M.; Ferrari, C.; Feruglio, C.; Gotz, D.; Gouiffes, C.; Hailey, C.

    2010-01-01

    Tracing the formation and evolution of all supermassive black holes, including the obscured ones, understanding how black holes influence their surroundings and how matter behaves under extreme conditions, are recognized as key science objectives to be addressed by the next generation of instruments. These are the main goals of the COSPIX proposal, made to ESA in December 2010 in the context of its call for selection of the M3 mission. In addition, COSPIX, will also provide key measurements on the non thermal Universe, particularly in relation to the question of the acceleration of particles, as well as on many other fundamental questions as for example the energetic particle content of clusters of galaxies. COSPIX is proposed as an observatory operating from 0.3 to more than 100 keV. The payload features a single long focal length focusing telescope offering an effective area close to ten times larger than any scheduled focusing mission at 30 keV, an angular resolution better than 20 arcseconds in hard X-rays, and polarimetric capabilities within the same focal plane instrumentation. In this paper, we describe the science objectives of the mission, its baseline design, and its performances, as proposed to ESA.

  15. Manual for obscuration code with space station applications

    NASA Technical Reports Server (NTRS)

    Marhefka, R. J.; Takacs, L.

    1986-01-01

    The Obscuration Code, referred to as SHADOW, is a user-oriented computer code to determine the case shadow of an antenna in a complex environment onto the far zone sphere. The surrounding structure can be composed of multiple composite cone frustums and multiply sided flat plates. These structural pieces are ideal for modeling space station configurations. The means of describing the geometry input is compatible with the NEC-BASIC Scattering Code. In addition, an interactive mode of operation has been provided for DEC VAX computers. The first part of this document is a user's manual designed to give a description of the method used to obtain the shadow map, to provide an overall view of the operation of the computer code, to instruct a user in how to model structures, and to give examples of inputs and outputs. The second part is a code manual that details how to set up the interactive and non-interactive modes of the code and provides a listing and brief description of each of the subroutines.

  16. A Tutorial on Hunting Statistical Significance by Chasing N

    PubMed Central

    Szucs, Denes

    2016-01-01

    There is increasing concern about the replicability of studies in psychology and cognitive neuroscience. Hidden data dredging (also called p-hacking) is a major contributor to this crisis because it substantially increases Type I error resulting in a much larger proportion of false positive findings than the usually expected 5%. In order to build better intuition to avoid, detect and criticize some typical problems, here I systematically illustrate the large impact of some easy to implement and so, perhaps frequent data dredging techniques on boosting false positive findings. I illustrate several forms of two special cases of data dredging. First, researchers may violate the data collection stopping rules of null hypothesis significance testing by repeatedly checking for statistical significance with various numbers of participants. Second, researchers may group participants post hoc along potential but unplanned independent grouping variables. The first approach ‘hacks’ the number of participants in studies, the second approach ‘hacks’ the number of variables in the analysis. I demonstrate the high amount of false positive findings generated by these techniques with data from true null distributions. I also illustrate that it is extremely easy to introduce strong bias into data by very mild selection and re-testing. Similar, usually undocumented data dredging steps can easily lead to having 20–50%, or more false positives. PMID:27713723

  17. Chasing polys: Interdisciplinary affinity and its connection to physics identity

    NASA Astrophysics Data System (ADS)

    Scott, Tyler D.

    This research is based on two motivations that merge by means of the frameworks of interdisciplinary affinity and physics identity. First, a goal of education is to develop interdisciplinary abilities in students' thinking and work. But an often ignored factor is students interests and beliefs about being interdisciplinary. Thus, this work develops and uses a framework called interdisciplinary affinity. It encompasses students interests in making connections across disciplines and their beliefs about their abilities to make those connections. The second motivation of this research is to better understand how to engage more students with physics. Physics identity describes how a student sees themselves in relation to physics. By understanding how physics identity is developed, researchers and educators can identify factors that increase interest and engagement in physics classrooms. Therefore, physics identity was used in conjunction with interdisciplinary affinity. Using a mixed methods approach, this research used quantitative data to identify the relationships interdisciplinary affinity has with physics identity and the physics classroom. These connections were explored in more detail using a case study of three students in a high school physics class. Results showed significant and positive relationships between interdisciplinary affinity and physics identity, including the individual interest and recognition components of identity. It also identified characteristics of physics classrooms that had a significant, positive relationship with interdisciplinary affinity. The qualitative case study highlighted the importance of student interest to the relationship between interdisciplinary affinity and physics identity. It also identified interest and mastery orientation as key to understanding the link between interdisciplinary affinity and the physics classroom. These results are a positive sign that by understanding interdisciplinary affinity and physics identity

  18. Plasma level monitoring of the major metabolites of diacetylmorphine (heroin) by the "chasing the dragon" route in severe heroin addicts.

    PubMed

    Dubois, N; Demaret, I; Ansseau, M; Rozet, E; Hubert, Ph; Charlier, C

    2013-01-01

    The objective of the present study was to verify if severe physical health problems frequently encountered in heroin addicts and the concomitant use of alcohol and legal or illegal drugs other than heroin influenced the pharmacokinetics of the major metabolites of heroin. We conducted a 90 minutes follow-up of the plasma concentrations of the pharmaceutical heroin, named diacetylmorphine (DAM), in patients recruited in a DAM assisted treatment centre. TADAM (Traitement Assisté par DiAcétylMorphine) aimed to compare the efficacy of heroin-assisted treatment (HAT) compared with methadone maintenance treatment (MMT) for heroin users considered as treatment resistant patients and who have severe physical and mental health problems. Eleven patients were recruited. Blood samples were collected at baseline and 15, 45 and 90 minutes after DAM administration. All patients received DAM by the "chasing the dragon" route. Plasma samples were analyzed by a previously described ultra-high pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC/MS-MS) method. A principal component analysis (PCA) was performed and 8 metabolite concentrations ratios were calculated to evaluate the influence of various factors (DAM dose, patient pathologies, concomitant use of medications, methadone, street heroin, alcohol and cocaine) on heroin metabolite pharmacokinetics. It seemed to be not affected by the DAM dose, patient pathologies and the concomitant use of medications, methadone, street heroin and alcohol. Cocaine use was the only parameter which showed differences in heroin pharmacokinetics. PMID:24579243

  19. Plasma level monitoring of the major metabolites of diacetylmorphine (heroin) by the "chasing the dragon" route in severe heroin addicts.

    PubMed

    Dubois, N; Demaret, I; Ansseau, M; Rozet, E; Hubert, Ph; Charlier, C

    2013-01-01

    The objective of the present study was to verify if severe physical health problems frequently encountered in heroin addicts and the concomitant use of alcohol and legal or illegal drugs other than heroin influenced the pharmacokinetics of the major metabolites of heroin. We conducted a 90 minutes follow-up of the plasma concentrations of the pharmaceutical heroin, named diacetylmorphine (DAM), in patients recruited in a DAM assisted treatment centre. TADAM (Traitement Assisté par DiAcétylMorphine) aimed to compare the efficacy of heroin-assisted treatment (HAT) compared with methadone maintenance treatment (MMT) for heroin users considered as treatment resistant patients and who have severe physical and mental health problems. Eleven patients were recruited. Blood samples were collected at baseline and 15, 45 and 90 minutes after DAM administration. All patients received DAM by the "chasing the dragon" route. Plasma samples were analyzed by a previously described ultra-high pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC/MS-MS) method. A principal component analysis (PCA) was performed and 8 metabolite concentrations ratios were calculated to evaluate the influence of various factors (DAM dose, patient pathologies, concomitant use of medications, methadone, street heroin, alcohol and cocaine) on heroin metabolite pharmacokinetics. It seemed to be not affected by the DAM dose, patient pathologies and the concomitant use of medications, methadone, street heroin and alcohol. Cocaine use was the only parameter which showed differences in heroin pharmacokinetics.

  20. Multiple scattering from clear atmosphere obscured by transparent crystal clouds in satellite-borne lidar sensing.

    PubMed

    Flesia, C; Starkov, A V

    1996-05-20

    The contribution of multiple scattering to a spaceborne lidar return from clear molecular atmosphere obscured by transparent upper-level crystal clouds is assessed by the use of the variance-reduction Monte Carlo technique. High anisotropy of scattering in the forward direction by polydispersions of ice crystals is the basis of a significant effect of multiple scattering for small values of the lidar receiver field of view. Because of scattering by large nonspherical crystal particles, the lidar signal backscattered from the molecular atmosphere under the cloud increases significantly compared with the single-scattering return. The ratio of the multiple-to-single-scattering contributions from the clear atmosphere hidden by the clouds is greater than from the crystal clouds themselves, and it is proportional to the values of cloud optical thickness.

  1. A Submillimeter Survey of Dust Continuum Emission in Local Dust-Obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Lee, Jong Chul; Hwang, Ho Seong; Lee, Gwang-Ho

    2015-08-01

    Dusty star-forming galaxies are responsible for the bulk of cosmic star formation at 1high redshift. The submillimeter data on the 'Rayleigh-Jeans' side of the infrared spectral energy distributions (SEDs) of these galaxies are crucial for deriving the physical parameters of the dust content. We therefore conduct a submillimeter survey of local dust-obscured galaxies (DOGs) with the Caltech Submillimeter Observatory and the Submillimeter Array to study their dust properties. We determine the dust masses and temperatures for 16 local DOGs from the SED fit, and compare them with other dusty galaxies to understand a possible evolutionary link among them.

  2. Chasing the Late Jurassic APW Monster Shift in Ontario Kimberlites

    NASA Astrophysics Data System (ADS)

    Kent, D. V.; Muttoni, G.; Gee, J. S.; Kjarsgaard, B. A.

    2012-12-01

    A 30° gap was recognized in a composite APW path when global poles from predominantly igneous rocks were assembled in North American coordinates using plate reconstructions (Kent & Irving 2010 JGR). The 'monster shift' occurred between a 160-190 Ma cluster of mean poles at 75-80°N 90-110°E to a 140-145 Ma grouping centered at 60-65°N ~200°E. There are hardly any intermediate igneous poles whereas the rather divergent directions from the Late Jurassic Morrison Formation published by Steiner & Helsley (1975 GSA Bulletin) are subject to adjustments for Colorado Plateau rotation and sedimentary inclination error, neither of which are precisely known for this redbed unit sampled in Colorado. On the other hand, similar large rapid swings have been recognized in the Late Jurassic APW path for Adria (Channell et al. 2010 Paleo3), suggesting a global phenomena. In an effort to fill the data gap between ~145 and 160 Ma, we sampled accessible outcrops/subcrops of kimberlites in the Timiskaming area of Ontario, Canada, that are associated with high precision U-Pb perovskite ages (Heamon & Kjarsgaard 2000 EPSL). We report initial results from two of the intrusions: the 153.6±2.4 Ma Peddie kimberlite from outcrop and the Triple B kimberlite that was accessible by trenching and is assumed to be the same age as the nearby 153.7±1.8 Ma Seed kimberlite as delineated by aeromagnetic surveys and borings. Systematic progressive thermal demagnetization indicated in each unit a dominant characteristic component with unblocking temperatures to 575° that presumably reflect a magnetite carrier that will be checked by further rock magnetic experiments. Samples from the Peddie kimberlite had stable downward (normal polarity) magnetizations whose mean direction gives a paleopole at 73°N 184°E. In contrast, samples from the Triple B kimberlite have upward (reverse polarity) magnetizations with a well-grouped direction whose (north) paleopole is 78°N 197°E, proximal to the Peddie

  3. Dust Obscured AGN are Masquerading as Star Formation in the Early Universe

    NASA Astrophysics Data System (ADS)

    Kirkpatrick, Allison; Pope, Alexandra; Sajina, Anna; Roebuck, Eric

    2016-01-01

    The buildup of stellar and black hole mass peaked during z=1-3, making this a key epoch for understanding how the interplay of star formation and an active galactic nucleus (AGN) drive galaxy evolution. IR luminous galaxies, which are massive and heavily dust obscured (LIR > 1011 Lsun), dominate the stellar growth during this era, and many are harboring a hidden AGN. I have quantified the contribution of AGN heating to the infrared emission of 343 IR luminous galaxies from z=0.5-2.8 using Spitzer mid-IR spectroscopy, available for every source, making this an unprecedented sample. I classify sources as star forming galaxies, AGN, or composites based on the presence of mid-IR continuum emission due to a dusty torus. My findings are: 1) Surprisingly, 60% of IR luminous galaxies show signs of some dust heating emanating from an AGN. I quantify the far-IR emission using deep Herschel imaging and find that the strength of mid-IR AGN emission is tightly correlated with the total contribution of an AGN to LIR, which has important consequences for calculating star formation rates in dusty high redshift galaxies. I demonstrate techniques to remove the contribution of AGN to LIR when mid-IR spectroscopy is available and when only limited photometry is available. 2) The composites are a separate class of galaxy which show a true mix of star formation and AGN activity in their mid- and far-IR emission. Because of dust obscuration, this activity is largely undetected at other wavelengths. This composite population is important for understanding galaxy evolution and makes up at least 30% of the deepest IR selected samples. I underscore the importance of considering composite galaxies separately in studies of star formation and black hole growth at high redshift.

  4. DUST-OBSCURED STAR FORMATION IN INTERMEDIATE REDSHIFT GALAXY CLUSTERS

    SciTech Connect

    Finn, Rose A.; Desai, Vandana; Rudnick, Gregory; Poggianti, Bianca; Bell, Eric F.; Hinz, Joannah; Zaritsky, Dennis; Jablonka, Pascale; Milvang-Jensen, Bo; Moustakas, John; Rines, Kenneth E-mail: jmoustakas@ucsd.ed

    2010-09-01

    We present Spitzer MIPS 24 {mu}m observations of sixteen 0.4 < z < 0.8 galaxy clusters drawn from the ESO Distant Cluster Survey. This is the first large 24 {mu}m survey of clusters at intermediate redshift. The depth of our imaging corresponds to a total IR luminosity of 8 x 10{sup 10} L{sub sun}, just below the luminosity of luminous infrared galaxies (LIRGs), and 6{sup +1}{sub -1}% of M{sub V} < -19 cluster members show 24 {mu}m emission at or above this level. We compare with a large sample of coeval field galaxies and find that while the fraction of cluster LIRGs lies significantly below that of the field, the IR luminosities of the field and cluster galaxies are consistent. However, the stellar masses of the EDisCS LIRGs are systematically higher than those of the field LIRGs. A comparison with optical data reveals that {approx}80% of cluster LIRGs are blue and the remaining 20% lie on the red sequence. Of LIRGs with optical spectra, 88{sup +4} {sub -5}% show [O II] emission with EW([O II]) > 5 A, and {approx}75% exhibit optical signatures of dusty starbursts. On average, the fraction of cluster LIRGs increases with projected clustercentric radius but remains systematically lower than the field fraction over the area probed (<1.5x R {sub 200}). The amount of obscured star formation declines significantly over the 2.4 Gyr interval spanned by the EDisCS sample, and the rate of decline is the same for the cluster and field populations. Our results are consistent with an exponentially declining LIRG fraction, with the decline in the field delayed by {approx}1 Gyr relative to the clusters.

  5. Continuous Turnover of Carotenes and Chlorophyll a in Mature Leaves of Arabidopsis Revealed by 14CO2 Pulse-Chase Labeling[OA

    PubMed Central

    Beisel, Kim Gabriele; Jahnke, Siegfried; Hofmann, Diana; Köppchen, Stephan; Schurr, Ulrich; Matsubara, Shizue

    2010-01-01

    Carotenoid turnover was investigated in mature leaves of Arabidopsis (Arabidopsis thaliana) by 14CO2 pulse-chase labeling under control-light (CL; 130 μmol photons m−2 s−1) and high-light (HL; 1,000 μmol photons m−2 s−1) conditions. Following a 30-min 14CO2 administration, photosynthetically fixed 14C was quickly incorporated in β-carotene (β-C) and chlorophyll a (Chl a) in all samples during a chase of up to 10 h. In contrast, 14C was not detected in Chl b and xanthophylls, even when steady-state amounts of the xanthophyll-cycle pigments and lutein increased markedly, presumably by de novo synthesis, in CL-grown plants under HL. Different light conditions during the chase did not affect the 14C fractions incorporated in β-C and Chl a, whereas long-term HL acclimation significantly enhanced 14C labeling of Chl a but not β-C. Consequently, the maximal 14C signal ratio between β-C and Chl a was much lower in HL-grown plants (1:10) than in CL-grown plants (1:4). In lut5 mutants, containing α-carotene (α-C) together with reduced amounts of β-C, remarkably high 14C labeling was found for α-C while the labeling efficiency of Chl a was similar to that of wild-type plants. The maximum 14C ratios between carotenes and Chl a were 1:2 for α-C:Chl a and 1:5 for β-C:Chl a in CL-grown lut5 plants, suggesting high turnover of α-C. The data demonstrate continuous synthesis and degradation of carotenes and Chl a in photosynthesizing leaves and indicate distinct acclimatory responses of their turnover to changing irradiance. In addition, the results are discussed in the context of photosystem II repair cycle and D1 protein turnover. PMID:20118270

  6. Pulse-chase analysis for studies of MHC class II biosynthesis, maturation, and peptide loading

    PubMed Central

    Hou, Tieying; Rinderknecht, Cornelia H; Hadjinicolaou, Andreas V; Busch, Robert; Mellins, Elizabeth

    2014-01-01

    Pulse-chase analysis is a commonly used technique for studying the synthesis, processing and transport of proteins. Cultured cells expressing proteins of interest are allowed to take up radioactively labeled amino acids for a brief interval (“pulse”), during which all newly synthesized proteins incorporate the label. The cells are then returned to non-radioactive culture medium for various times (“chase”), during which proteins may undergo conformational changes, trafficking, or degradation. Proteins of interest are isolated (usually by immunoprecipitation) and resolved by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and the fate of radiolabeled molecules is examined by autoradiography. This chapter describes a pulse-chase protocol suitable for studies of major histocompatibility complex (MHC) class II biosynthesis and maturation. We discuss how results are affected by the recognition by certain anti-class II antibodies of distinct class II conformations associated with particular biosynthetic states. Our protocol can be adapted to follow the fate of many other endogenously synthesized proteins, including viral or transfected gene products, in cultured cells. PMID:23329504

  7. A Novel Pulse-Chase Paradigm to Visualize the Trafficking of Transport Vesicles in Neurons

    NASA Astrophysics Data System (ADS)

    Al-Bassam, Sarmad

    In neurons transmembrane proteins are targeted to dendrites in vesicles that traffic solely within the somatodendritic compartment. How these vesicles are retained within the somatodendritic domain is unknown. Here we adapt a novel pulse chase system that allows synchronous release of exogenous transmembrane proteins from the endoplasmic reticulum using FKBP12 and Rapamycin. We demonstrate proof-of-concept and establish protein trafficking controls in incremental steps. We demonstrate the utility of this approach in studying protein trafficking and establish parameters for analysis of time-lapse images. We implement this novel pulse-chase strategy to track the movements of post-Golgi transport vesicles. Surprisingly, we found that post-Golgi vesicles carrying dendritic proteins were equally likely to enter axons and dendrites. However, once such vesicles entered the axon they very rarely moved beyond the axon initial segment, but instead either halted or reversed direction in an actin and Myosin Va-dependent manner. In contrast, vesicles carrying either an axonal or a nonspecifically localized protein only rarely halted or reversed and instead generally proceeded to the distal axon. Thus, our results are consistent with the axon initial segment behaving as a vesicle filter that mediates the differential trafficking of transport vesicles.

  8. Cell traction in collective cell migration and morphogenesis: The chase and run mechanism

    PubMed Central

    Szabó, András; Mayor, Roberto

    2015-01-01

    Directional collective cell migration plays an important role in development, physiology, and disease. An increasing number of studies revealed key aspects of how cells coordinate their movement through distances surpassing several cell diameters. While physical modeling and measurements of forces during collective cell movements helped to reveal key mechanisms, most of these studies focus on tightly connected epithelial cultures. Less is known about collective migration of mesenchymal cells. A typical example of such behavior is the migration of the neural crest cells, which migrate large distances as a group. A recent study revealed that this persistent migration is aided by the interaction between the neural crest and the neighboring placode cells, whereby neural crest chase the placodes via chemotaxis, but upon contact both populations undergo contact inhibition of locomotion and a rapid reorganization of cellular traction. The resulting asymmetric traction field of the placodes forces them to run away from the chasers. We argue that this chase and run interaction may not be specific only to the neural crest system, but could serve as the underlying mechanism for several morphogenetic processes involving collective cell migration. PMID:26267782

  9. Dynamic properties of chasers in a moving queue based on a delayed chasing model

    NASA Astrophysics Data System (ADS)

    Ning, Guo; Jian-Xun, Ding; Xiang, Ling; Qin, Shi; Reinhart, Kühne

    2016-05-01

    A delayed chasing model is proposed to simulate the chase behavior in the queue, where each member regards the closest one ahead as the target, and the leader is attracted to a target point with slight fluctuation. When the initial distances between neighbors possess an identical low value, the fluctuating target of the leader can cause an amplified disturbance in the queue. After a long period of time, the queue recovers the stable state from the disturbance, forming a straight-line-like pattern again, but distances between neighbors grow. Whether the queue can keep stable or not depends on initial distance, desired velocity, and relaxation time. Furthermore, we carry out convergence analysis to explain the divergence transformation behavior and confirm the convergence conditions, which is in approximate agreement with simulations. Project supported by the National Natural Science Foundation of China (Grant Nos. 71071044, 71001001, 71201041, and 11247291), the Doctoral Program of the Ministry of Education of China (Grant Nos. 20110111120023 and 20120111120022), the Postdoctoral Fund Project of China (Grant No. 2013M530295), the National Basic Research Program of China (Grant No. 2012CB725404), and 1000 Plan for Foreign Talent, China (Grant No. WQ20123400070).

  10. XB-70A #1 liftoff with TB-58A chase aircraft

    NASA Technical Reports Server (NTRS)

    1960-01-01

    This photo shows XB-70A #1 taking off on a research flight, escorted by a TB-58 chase plane. The TB-58 (a prototype B-58 modified as a trainer) had a dash speed of Mach 2. This allowed it to stay close to the XB-70 as it conducted its research maneuvers. When the XB-70 was flying at or near Mach 3, the slower TB-58 could often keep up with it by flying lower and cutting inside the turns in the XB-70's flight path when these occurred. The XB-70 was the world's largest experimental aircraft. It was capable of flight at speeds of three times the speed of sound (roughly 2,000 miles per hour) at altitudes of 70,000 feet. It was used to collect in-flight information for use in the design of future supersonic aircraft, military and civilian. The major objectives of the XB-70 flight research program were to study the airplane's stability and handling characteristics, to evaluate its response to atmospheric turbulence, and to determine the aerodynamic and propulsion performance. In addition there were secondary objectives to measure the noise and friction associated with airflow over the airplane and to determine the levels and extent of the engine noise during takeoff, landing, and ground operations. The XB-70 was about 186 feet long, 33 feet high, with a wingspan of 105 feet. Originally conceived as an advanced bomber for the United States Air Force, the XB-70 was limited to production of two aircraft when it was decided to limit the aircraft's mission to flight research. The first flight of the XB-70 was made on Sept. 21, 1964. The number two XB-70 was destroyed in a mid-air collision on June 8, 1966. Program management of the NASA-USAF research effort was assigned to NASA in March 1967. The final flight was flown on Feb. 4, 1969. Designed by North American Aviation (later North American Rockwell and still later, a division of Boeing) the XB-70 had a long fuselage with a canard or horizontal stabilizer mounted just behind the crew compartment. It had a sharply swept 65

  11. Chasing Chooz

    NASA Astrophysics Data System (ADS)

    Ramond, P.

    We relate the MNS and CKM mixing matrices using ideas from grand unification. We catalog models in terms of the family symmetries of the down quark mass matrices, and emphasize the role of the Cabibbo angle in the lepton mixing matrix. We find a large class of models with an observable CHOOZ angle ˜λ /√ {2}.

  12. Chasing Chooz

    NASA Astrophysics Data System (ADS)

    Ramond, P.

    2004-01-01

    We relate the MNS and CKM mixing matrices using ideas from grand unification. We catalog models in terms of the family symmetries of the down quark mass matrices, and emphasize the role of the Cabibbo angle in the lepton mixing matrix. We find a large class of models with an observable CHOOZ angle ˜ λ λ {√ 2 }};.

  13. Chasing Sounds

    PubMed Central

    Neiworth, Julie J

    2012-01-01

    Prior work with Wright and others demonstrated that rhesus monkeys recognized the relative relationships of notes in common melodies. As an extension of tests of pattern similarities, tamarins were habituated to 3-sound unit patterns in an AAB or ABB form that were human phonemes, piano notes, or monkey calls. The subjects were tested with novel sounds in each category constructed either to match the prior pattern or to violate the prior habituated pattern. The monkeys attended significantly more to a violation of their habituated pattern to a new pattern when human phonemes were used, and there was a trend difference in attention toward pattern violations with melodies. Monkey call patterns generated a variety of behavioral responses, were less likely to show habituation, and did not generate a strong attention reaction to changes in the patterns. Monkeys can extract abstract rules and patterns from auditory stimuli but the stimuli, by their nature, may generate competing responses which block processing of abstract regularities. PMID:23219981

  14. The Star Formation Histories of z ~ 2 Dust-obscured Galaxies and Submillimeter-selected Galaxies

    NASA Astrophysics Data System (ADS)

    Bussmann, R. S.; Dey, Arjun; Armus, L.; Brown, M. J. I.; Desai, V.; Gonzalez, A. H.; Jannuzi, B. T.; Melbourne, J.; Soifer, B. T.

    2012-01-01

    The Spitzer Space Telescope has identified a population of ultraluminous infrared galaxies (ULIRGs) at z ~ 2 that may play an important role in the evolution of massive galaxies. We measure the stellar masses (M *) of two populations of Spitzer-selected ULIRGs that have extremely red R - [24] colors (dust-obscured galaxies, or DOGs) and compare our results with submillimeter-selected galaxies (SMGs). One set of 39 DOGs has a local maximum in their mid-infrared (mid-IR) spectral energy distribution (SED) at rest frame 1.6 μm associated with stellar emission ("bump DOGs"), while the other set of 51 DOGs have power-law mid-IR SEDs that are typical of obscured active galactic nuclei ("power-law DOGs"). We measure M * by applying Charlot & Bruzual stellar population synthesis models to broadband photometry in the rest-frame ultraviolet, optical, and near-infrared of each of these populations. Assuming a simple stellar population and a Chabrier initial mass function, we find that power-law DOGs and bump DOGs are on average a factor of 2 and 1.5 more massive than SMGs, respectively (median and inter-quartile M * values for SMGs, bump DOGs, and power-law DOGs are log(M */M ⊙) = 10.42+0.42 - 0.36, 10.62+0.36 - 0.32, and 10.71+0.40 - 0.34, respectively). More realistic star formation histories drawn from two competing theories for the nature of ULIRGs at z ~ 2 (major merger versus smooth accretion) can increase these mass estimates by up to 0.5 dex. A comparison of our stellar masses with the instantaneous star formation rate (SFR) in these z ~ 2 ULIRGs provides a preliminary indication supporting high SFRs for a given M *, a situation that arises more naturally in major mergers than in smooth accretion-powered systems.

  15. Characterization of the OPAL LiDAR under controlled obscurant conditions

    NASA Astrophysics Data System (ADS)

    Cao, Xiaoying; Church, Philip; Matheson, Justin

    2016-05-01

    Neptec Technologies' OPAL-120 3D LiDAR is optimized for obscurant penetration. The OPAL-120 uses a scanning mechanism based on the Risley prism pair. The scan patterns are created by rotating two prisms under independent motor control. The geometry and material properties of the prisms define the conical field-of-view of the sensor, which can be built to between 60 to 120 degrees. The OPAL-120 was recently evaluated using a controlled obscurant chamber capable of generating clouds of obscurants over a depth of 22m. Obscurants used in this investigation include: Arizona road dust, water fog, and fog-oil. The obscurant cloud optical densities were monitored with a transmissometer. Optical depths values ranged from an upper value of 6 and progressively decreased to 0. Targets were positioned at the back of the obscurant chamber at a distance of 60m from the LiDAR. The targets are made of a foreground array of equally spaced painted wood stripes in front of a solid background. Reflectivity contrasts were achieved with foreground/background combinations of white/white, white/black and black/white. Data analysis will be presented on the effect of optical densities on range and cross-range resolution, and accuracy. The analysis includes the combinations of all obscurant types and target reflectivity contrasts.

  16. Smokes and obscurants: A health and environmental effects data base assessment: A first-order, environmental screening and ranking of Army smokes and obscurants: Phase 1 report

    SciTech Connect

    Shinn, J.H.; Martins, S.A.; Cederwall, P.L.; Gratt, L.B.

    1985-03-01

    An initial environmental screening and ranking is provided for each Army smoke and obscurant (S and O) depending on smoke type and smoke-generating device. This was done according to the magnitude of the impact area, the characteristic environmental concentration, the relative inhalation toxicity, the relative toxicity when ingested by animals, the aquatic toxicity, the environmental mobility when freshly deposited, and the ultimate mobility and fate in the environment. The major smoke types considered were various forms of white phosphorus (WP), red phosphorus (RP), hexachloroethane-derived smokes (HC), fog oil (SGF-2), diesel fuel smokes (DF), and some infrared obscuring agents (IR).

  17. 76 FR 31955 - Jonathan and Jayne Chase; Notice of Application Accepted for Filing With the Commission, Intent...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-02

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Jonathan and Jayne Chase; Notice of Application Accepted for Filing With the... an Expedited Schedule for Processing Take notice that the following hydroelectric application...

  18. A pulse-chase strategy for EdU labelling assay is able to rapidly quantify cell division orientation.

    PubMed

    Yin, Xiaofeng; Tsukaya, Hirokazu

    2016-09-01

    Measurement of the direction of cell division is an important, yet difficult, task to analyse how a plant organ acquires its final shape from an initially small group of cells. We introduce a method that rapidly and easily quantifies cell division direction and is applicable to all plant species. A pulse-chase strategy for 5-ethynyl-2'-deoxyuridine (EdU) labelling assay was established and was shown to be successful for leaves of Arabidopsis thaliana (Arabidopsis) and Juncus prismatocarpus. By optimization of the pulse and chase periods, most of the signals obtained were sets of daughter nuclei. For Arabidopsis, the optimal time was a 45-min pulse and a 7-h chase. For J. prismatocarpus, the optimal time was a 2-h pulse and a 13.5-h chase. The positions of the daughter nuclei were used to quantify cell division direction in the Arabidopsis leaf primordia. Overall, cell division along the proximal-distal axis was more frequent than along the medial-lateral axis. In petiole, major vein, minor vein and margin areas, the major cell division direction seemed to be coincident with the direction of auxin flow. The advantages of our method over the few methods used previously are discussed. We anticipate that it will provide opportunities to study plant development in the near future.

  19. Deep brain stimulation of the subthalamic nucleus transiently enhances loss-chasing behaviour in patients with Parkinson's disease.

    PubMed

    Rogers, Robert D; Wielenberg, Birgit; Wojtecki, Lars; Elben, Saskia; Campbell-Meiklejohn, Daniel; Schnitzler, Alfons

    2011-09-01

    Dopaminergic treatments are associated with impulse control disorders such as pathological gambling in a subset of patients with Parkinson's Disease. While deep brain stimulation of the subthalamic nucleus has been reported to reduce symptoms of impulse control disorders in some Parkinson's Disease patients, little is known about its specific effects on gambling behaviour. In this experiment, we investigated the effects of deep brain stimulation of the subthalamic nucleus on one of the central features of pathological gambling: the tendency to chase losses. Loss-chasing is associated with impaired control over gambling behaviour and it is one of the most salient features of pathological gambling as it presents in the clinic. Twenty two patients with advanced idiopathic Parkinson's Disease and chronically implanted subthalamic nucleus electrodes for deep brain stimulation completed a simple laboratory model of loss-chasing behaviour twice: once with and once without stimulation. Exploratory analysis indicated that deep brain stimulation of the subthalamic nucleus increased the value of losses chased by patients with Parkinson's Disease when shifting from off- to on-stimulation. These effects were not attributable to changes in state affect or to the motor impairments produced by the withdrawal of deep brain stimulation of the subthalamic nucleus. The effects of the stimulation on the value of losses chased were more pronounced in female than in male patients and reduced in patients taking dopamine receptor agonists. Collectively, these results suggest that deep brain stimulation of the subthalamic nucleus can transiently alter the evaluation of accumulated losses during gambling episodes in idiopathic Parkinson's Disease. PMID:21726554

  20. Measuring Subvisible Particles in Protein Formulations Using a Modified Light Obscuration Sensor with Improved Detection Capabilities.

    PubMed

    Ríos Quiroz, Anacelia; Québatte, Gabriela; Stump, Fabian; Finkler, Christof; Huwyler, Joerg; Schmidt, Roland; Mahler, Hanns-Christian; Koulov, Atanas V; Adler, Michael

    2015-06-16

    Although light obscuration is the "gold standard" for subvisible particle measurements in biopharmaceutical products, the current technology has limitations with respect to the detection of translucent proteinaceous particles and particles of sizes smaller and around 2 μm. Here, we describe the evaluation of a modified light obscuration sensor utilizing a novel measuring mode. Whereas standard light obscuration methodology monitors the height (amplitude) of the signal, the new approach monitors its length (width). Experimental evaluation demonstrated that this new detection mode leads to improved detection of subvisible particles of sizes smaller than 2 μm, reduction of artifacts during measurements especially of low concentrations of translucent protein particles, and higher counting accuracy as compared to flow imaging microscopy and standard light obscuration measurements.

  1. Characterizing the redshifts and luminosities of WISE selected obscured AGN using SALT optical spectra.

    NASA Astrophysics Data System (ADS)

    Hviding, Raphael E.; Hickox, Ryan C.; Hainline, Kevin N.; Carroll, Christopher M.; DiPompeo, Mike A.; Jones, Mackenzie L.

    2016-08-01

    We present the results of several optical spectroscopic surveys covering over 100 candidate luminous obscured active galactic nuclei (AGN) identified by their mid-infrared emission detected with the Wide-Field Infrared Survey Explorer (WISE). These galaxies were selected based on red WISE colors and galaxy-like optical emission, and were studied using long-slit optical spectroscopy with the Robert Stobie Spectrograph (RSS) on the Southern African Large Telescope (SALT). Our spectra were analyzed to obtain redshifts and emission line flux ratios for each galaxy. These results verify that WISE is an effective section method for luminous obscured AGN, allow for the characterization of redshifts and luminosities of the WISE color selected obscured AGN population, and could potentially contribute to large statistical studies of obscured AGN distributions in the future.

  2. The shadow principle: An optimal survival strategy for a prey chased by random predators

    NASA Astrophysics Data System (ADS)

    Moreau, M.; Bénichou, O.; Oshanin, G.; Voituriez, R.

    2013-07-01

    We consider a lattice model of the annihilation process A+B→B, when a mobile prey A is chased by identical, independent predators B performing random motions until one of them finds A and destroys it. It is assumed that each predator follows some “most probable” trajectory around which it performs a random motion. It is shown that, if the random motion of the predators satisfies certain conditions, the prey A can maximize its survival probability by following a specific trajectory which mimics the preferred trajectories of the predators: we call this optimal trajectory as the “shadow” of the predator. This is an extension of the so-called “Pascal Principle”, studied in the recent literature. We discuss the conditions which allow for such extensions, and give examples where they are realized.

  3. Behaviorism Makes Its Debut: A Review of Lattal and Chase's Behavior Theory and Philosophy

    PubMed Central

    Zuriff, G.E

    2005-01-01

    Behavior Theory and Philosophy, masterfully edited by Lattal and Chase, is a collection of 21 papers by major behaviorists, presented and discussed at a conference on the intersection of philosophy and behavior analysis held at West Virginia University in 2000. The chapters in Part I are devoted to philosophy of science (causality, constructs, theory, explanation, reductionism) and the relations among behavior analysis and several contemporary philosophical movements (humanism, empiricism, pragmatism, selectionism, analytic philosophy). Part II examines behavior-analytic interpretations of mentalistic concepts (intention, imagination, ethics, cognition). Part III presents extensions and applications of basic research in behavior analysis (verbal behavior, creativity, development, education, disability, and corporate culture). The publication of this book signals that behaviorism has developed mature philosophical foundations.

  4. Biosynthesis of Nudicaulins: A (13) CO2 -pulse/chase labeling study with Papaver nudicaule.

    PubMed

    Tatsis, Evangelos C; Eylert, Eva; Maddula, Ravi Kumar; Ostrozhenkova, Elena; Svatoš, Aleš; Eisenreich, Wolfgang; Schneider, Bernd

    2014-07-21

    Nudicaulins are unique alkaloids responsible for the yellow color of the petals of some papaveraceaous plants. To elucidate the unknown biosynthetic origin of the skeleton, a (13) CO2 -pulse/chase experiment was performed with growing Papaver nudicaule plants. (13) C NMR analysis revealed more than 20 multiple (13) C-enriched isotopologues in nudicaulins from the petals of (13) CO2 -labeled plants. The complex labeling pattern was compared with the isotopologue composition of a kaempferol derivative that was isolated from petals of the same (13) CO2 -labeled plants. The deconvolution of the labeling profiles indicated that the nudicaulin scaffold is assembled from products or intermediates of indole metabolism, the phenylpropanoid pathway, and the polyketide biosynthesis. Naringenin-type compounds and tryptophan/tryptamine are potential substrates for the condensation reaction finally generating the aglycone skeleton of nudicaulins.

  5. Chasing Science at Sea: Racing Hurricanes, Stalking Sharks, and Living Undersea With Ocean Experts

    NASA Astrophysics Data System (ADS)

    Lee, Cindy

    2008-12-01

    Ellen Prager's new book, Chasing Science at Sea, is a personal account of why fieldwork is so important in many areas of ocean science, and how exciting that fieldwork can be. Prager has interwoven her own story of studying carbonates at the interface between biology and geology with stories from friends and colleagues. Storm stories and up-close-and-personal encounters with ocean creatures such as reef squid, marine iguanas, and whales abound. Throughout the book, she emphasizes the idea that the combination of observations and serendipity plays a critical role in science, and she gives examples of where this combination has led to especially important discoveries (e.g., that of hydrothermal vent organisms).

  6. Black carbon, particle number concentration and nitrogen oxide emission factors of random in-use vehicles measured with the on-road chasing method

    NASA Astrophysics Data System (ADS)

    Ježek, I.; Katrašnik, T.; Westerdahl, D.; Močnik, G.

    2015-06-01

    The chasing method was used in an on-road measurement campaign, and emission factors (EF) of black carbon (BC), particle number (PN) and nitrogen oxides (NOx) were determined for 139 individual vehicles of different types encountered on the roads. The aggregated results provide EFs for BC, NOx and PN for three vehicle categories: goods vehicles, gasoline and diesel passenger cars. This is the first on-road measurement study where BC EFs of numerous individual diesel cars were determined in real-world driving conditions. We found good agreement between EFs of goods vehicles determined in this campaign and the results of previous studies that used either chasing or remote sensing measurement techniques. The composition of the sampled car fleet determined from the national vehicle registry information is reflective of Eurostat statistical data on the Slovenian and European vehicle fleet. The median BC EF of diesel and gasoline cars that were in use for less than 5 years, decreased by 60 and 47% from those in use for 5-10 years, respectively, the median NOx and PN EFs, of goods vehicles that were in use for less than five years, decreased from those in use for 5-10 years by 52 and 67%, respectively. The influence of engine maximum power of the measured EFs showed an increase in NOx EF from least to more powerful vehicles with diesel engines. Finally a disproportionate contribution of high emitters to the total emissions of the measured fleet was found; the top 25% of emitting diesel cars contributed 63, 47 and 61% of BC, NOx and PN emissions respectively. With the combination of relatively simple on-road measurements with sophisticated post processing individual vehicles EF can be determined and useful information about the fleet emissions can be obtained by exactly representing vehicles which contribute disproportionally to vehicle fleet emissions; and monitor how the numerous emission reduction approaches are reflected in on-road driving conditions.

  7. Improved clearance of radiolabeled biotinylated monoclonal antibody following the infusion of avidin as a {open_quotes}chase{close_quotes} without decreased accumulation in the target tumor

    SciTech Connect

    Kobayashi, Hisataka; Sakahara, Harumi; Hosono, Makoto

    1994-10-01

    The techniques of radioimmunoimaging and radioimmunotherapy suffer from prolonged high background radioactivity because intravenously injected antibodies remain in the circulation and in the organs far longer than necessary for effective binding to the target. To decrease background and increase radionuclide excretion without decreasing the dose of radioactivity delivered to the target tumor, we used radiolabeled biotinylated antibodies followed by a {open_quotes}chase{close_quotes} avidin injection. A mouse monoclonal antibody, OST7 (lgG1), which reacts with human osteosarcoma, was biotinylated and labeled with {sup 125}I, {sup 131}I or {sup 22m}Tc. Radiolabeled biotinylated OST7 (10 {mu}g) was administered intravenously into nude mice bearing human osteosarcomas and 30 {mu}g of avidin was injected intravenously 6 or 24 hr later. Following avidin injection in mice pretreated with radiolabeled biotinylated antibodies, radioactivity was promptly cleared from the blood and deposited in the liver and spleen, after which radioiodine was rapidly detached from the antibody and excreted in the urine. The tumor-to-blood ratios at 6 and 24 hr after the injection of {sup 125}I-labeled biotinylated OST7 increased compared with the values before the avidin chase without any loss of tumor radioactivity. Furthermore, the tumor -to-background radioactivity ratio was improved and better images were obtained more rapidly after the injection of radiolabeled biotiny-lated antibodies than with conventional immunoscintigraphy. This method may find application in clinical radio-immunoimaging, especially using short half-life radionuclides such as {sup 39m}Tc and {sup 123}I. 24 refs., 8 figs., 3 tabs.

  8. The HELLAS2XMM survey. XIII. Multi-component analysis of the spectral energy distribution of obscured AGN

    NASA Astrophysics Data System (ADS)

    Pozzi, F.; Vignali, C.; Comastri, A.; Bellocchi, E.; Fritz, J.; Gruppioni, C.; Mignoli, M.; Maiolino, R.; Pozzetti, L.; Brusa, M.; Fiore, F.; Zamorani, G.

    2010-07-01

    Aims: We combine near-to-mid-IR Spitzer data with shorter wavelength observations (optical to X-rays) to get insight into the properties of a sample of luminous, obscured active galactic nuclei (AGN). We aim at modelling their broad-band spectral energy distributions (SEDs) in order to estimate the main parameters related to the dusty torus that is assumed to be responsible for the reprocessed IR emission. Our final goal is to estimate the intrinsic nuclear luminosities and the Eddington ratios for our luminous, obscured AGN. Methods: The sample comprises 16 obscured high-redshift (0.9 ⪉ z ⪉ 2.1), X-ray luminous quasars (L2-10 keV ~ 1044 erg s-1) selected from the HELLAS2XMM survey in the 2-10 keV band. The optical-IR SEDs are described by a multi-component model that includes a stellar component to account for the optical and near-IR emission, an AGN component that dominates in the mid-IR (mainly emission from a dusty torus heated by nuclear radiation), and a starburst to reproduce the far-IR bump. A radiative transfer code to compute the spectrum and intensity of dust reprocessed emission was extensively tested against our multiwavelength data. While the torus parameters and the BH accretion luminosities are a direct output of the SED-fitting procedure, the BH masses were estimated indirectly by means of the local Mbulge-MBH relation. Results: The majority (~80%) of the sources show moderate optical depth (τ9.7 µm ≤ 3), and the derived column densities NH are consistent with the X-ray inferred values (1022 ⪉ NH ⪉ 3 × 1023 cm-2) for most of the objects, confirming that the sources are moderately obscured Compton-thin AGN. Accretion luminosities in the range 5 × 1044 ⪉ Lbol ⪉ 4 × 1046 erg s-1 are inferred from the multiwavelength fitting procedure. We compare model luminosities with those obtained by integrating the observed SED, finding that the latter are lower by a factor of ~2 in the median. The discrepancy can be as high as an order of

  9. CHASE domain-containing receptors play an essential role in the cytokinin response of the moss Physcomitrella patens.

    PubMed

    von Schwartzenberg, Klaus; Lindner, Ann-Cathrin; Gruhn, Njuscha; Šimura, Jan; Novák, Ondřej; Strnad, Miroslav; Gonneau, Martine; Nogué, Fabien; Heyl, Alexander

    2016-02-01

    While the molecular basis for cytokinin action is quite well understood in flowering plants, little is known about the cytokinin signal transduction in early diverging land plants. The genome of the bryophyte Physcomitrella patens (Hedw.) B.S. encodes three classical cytokinin receptors, the CHASE domain-containing histidine kinases, CHK1, CHK2, and CHK3. In a complementation assay with protoplasts of receptor-deficient Arabidopsis thaliana as well as in cytokinin binding assays, we found evidence that CHK1 and CHK2 receptors can function in cytokinin perception. Using gene targeting, we generated a collection of CHK knockout mutants comprising single (Δchk1, Δchk2, Δchk3), double (Δchk1,2, Δchk1,3, Δchk2,3), and triple (Δchk1,2,3) mutants. Mutants were characterized for their cytokinin response and differentiation capacities. While the wild type did not grow on high doses of cytokinin (1 µM benzyladenine), the Δchk1,2,3 mutant exhibited normal protonema growth. Bud induction assays showed that all three cytokinin receptors contribute to the triggering of budding, albeit to different extents. Furthermore, while the triple mutant showed no response in this bioassay, the remaining mutants displayed budding responses in a diverse manner to different types and concentrations of cytokinins. Determination of cytokinin levels in mutants showed no drastic changes for any of the cytokinins; thus, in contrast to Arabidopsis, revealing only small impacts of cytokinin signaling on homeostasis. In summary, our study provides a first insight into the molecular action of cytokinin in an early diverging land plant and demonstrates that CHK receptors play an essential role in bud induction and gametophore development.

  10. CHASE domain-containing receptors play an essential role in the cytokinin response of the moss Physcomitrella patens

    PubMed Central

    von Schwartzenberg, Klaus; Lindner, Ann-Cathrin; Gruhn, Njuscha; Šimura, Jan; Novák, Ondřej; Strnad, Miroslav; Gonneau, Martine; Nogué, Fabien; Heyl, Alexander

    2016-01-01

    While the molecular basis for cytokinin action is quite well understood in flowering plants, little is known about the cytokinin signal transduction in early diverging land plants. The genome of the bryophyte Physcomitrella patens (Hedw.) B.S. encodes three classical cytokinin receptors, the CHASE domain-containing histidine kinases, CHK1, CHK2, and CHK3. In a complementation assay with protoplasts of receptor-deficient Arabidopsis thaliana as well as in cytokinin binding assays, we found evidence that CHK1 and CHK2 receptors can function in cytokinin perception. Using gene targeting, we generated a collection of CHK knockout mutants comprising single (Δchk1, Δchk2, Δchk3), double (Δchk1,2, Δchk1,3, Δchk2,3), and triple (Δchk1,2,3) mutants. Mutants were characterized for their cytokinin response and differentiation capacities. While the wild type did not grow on high doses of cytokinin (1 µM benzyladenine), the Δchk1,2,3 mutant exhibited normal protonema growth. Bud induction assays showed that all three cytokinin receptors contribute to the triggering of budding, albeit to different extents. Furthermore, while the triple mutant showed no response in this bioassay, the remaining mutants displayed budding responses in a diverse manner to different types and concentrations of cytokinins. Determination of cytokinin levels in mutants showed no drastic changes for any of the cytokinins; thus, in contrast to Arabidopsis, revealing only small impacts of cytokinin signaling on homeostasis. In summary, our study provides a first insight into the molecular action of cytokinin in an early diverging land plant and demonstrates that CHK receptors play an essential role in bud induction and gametophore development. PMID:26596764

  11. Heavy Dust Obscuration of z = 7 Galaxies in a Cosmological Hydrodynamic Simulation

    NASA Astrophysics Data System (ADS)

    Kimm, Taysun; Cen, Renyue

    2013-10-01

    Hubble Space Telescope observations with the Wide Field Camera 3/Infrared reveal that galaxies at z ~ 7 have very blue ultraviolet (UV) colors, consistent with these systems being dominated by young stellar populations with moderate or little attenuation by dust. We investigate UV and optical properties of the high-z galaxies in the standard cold dark matter model using a high-resolution adaptive mesh refinement cosmological hydrodynamic simulation. For this purpose, we perform panchromatic three-dimensional dust radiative transfer calculations on 198 galaxies of stellar mass 5 × 108-3 × 1010 M ⊙ with three parameters: the dust-to-metal ratio, the extinction curve, and the fraction of directly escaped light from stars (f esc). Our stellar mass function is found to be in broad agreement with Gonzalez et al., independent of these parameters. We find that our heavily dust-attenuated galaxies (AV ~ 1.8) can also reasonably match modest UV-optical colors, blue UV slopes, as well as UV luminosity functions, provided that a significant fraction (~10%) of light directly escapes from them. The observed UV slope and scatter are better explained with a Small-Magellanic-Cloud-type extinction curve, whereas a Milky-Way-type curve also predicts blue UV colors due to the 2175 Å bump. We expect that upcoming observations by the Atacama Large Millimeter/submillimeter Array will be able to test this heavily obscured model.

  12. HEAVY DUST OBSCURATION OF z = 7 GALAXIES IN A COSMOLOGICAL HYDRODYNAMIC SIMULATION

    SciTech Connect

    Kimm, Taysun; Cen, Renyue

    2013-10-10

    Hubble Space Telescope observations with the Wide Field Camera 3/Infrared reveal that galaxies at z ∼ 7 have very blue ultraviolet (UV) colors, consistent with these systems being dominated by young stellar populations with moderate or little attenuation by dust. We investigate UV and optical properties of the high-z galaxies in the standard cold dark matter model using a high-resolution adaptive mesh refinement cosmological hydrodynamic simulation. For this purpose, we perform panchromatic three-dimensional dust radiative transfer calculations on 198 galaxies of stellar mass 5 × 10{sup 8}-3 × 10{sup 10} M{sub ☉} with three parameters: the dust-to-metal ratio, the extinction curve, and the fraction of directly escaped light from stars (f{sub esc}). Our stellar mass function is found to be in broad agreement with Gonzalez et al., independent of these parameters. We find that our heavily dust-attenuated galaxies (A{sub V} ∼ 1.8) can also reasonably match modest UV-optical colors, blue UV slopes, as well as UV luminosity functions, provided that a significant fraction (∼10%) of light directly escapes from them. The observed UV slope and scatter are better explained with a Small-Magellanic-Cloud-type extinction curve, whereas a Milky-Way-type curve also predicts blue UV colors due to the 2175 Å bump. We expect that upcoming observations by the Atacama Large Millimeter/submillimeter Array will be able to test this heavily obscured model.

  13. Disk, merger, or outflow? Molecular gas kinematics in two powerful obscured QSOs at z ≥ 3.4

    NASA Astrophysics Data System (ADS)

    Polletta, M.; Nesvadba, N. P. H.; Neri, R.; Omont, A.; Berta, S.; Bergeron, J.

    2011-09-01

    We report on the detection of bright CO(4-3) line emission in two powerful, obscured quasars discovered in the SWIRE survey, SW022513 and SW022550 at z ≥ 3.4. We analyze the line strength and profile to determine the gas mass, dynamical mass, and the gas dynamics for both galaxies. In SW022513 we may have found the first evidence for a molecular, AGN-driven wind in the early Universe. The line profile in SW022513 is broad (FWHM=1000 km s-1) and blueshifted by -200 km s-1 relative to systemic (where the systemic velocity is estimated from the narrow components of ionized gas lines, as is commonly done for AGN at low and high redshifts). SW022550 has a more regular, double-peaked profile, which is marginally spatially resolved in our data, consistent with either a merger or an extended disk. The molecular gas masses, 4 × 1010 M⊙, are large and account for <30% of the stellar mass, making these obscured QSOs as gas rich as other powerful CO emitting galaxies at high redshift, i.e., submillimeter galaxies. Our sources exhibit relatively lower star-formation efficiencies compared to other dusty, powerful starburst galaxies at high redshift. We speculate that this could be a consequence of the AGN perturbing the molecular gas. Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).

  14. Obscured and powerful AGN and starburst activities at z ~ 3.5

    NASA Astrophysics Data System (ADS)

    Polletta, M.; Omont, A.; Berta, S.; Bergeron, J.; Stalin, C. S.; Petitjean, P.; Giorgetti, M.; Trinchieri, G.; Srianand, R.; McCracken, H. J.; Pei, Y.; Dannerbauer, H.

    2008-12-01

    Aims: Short phases of coeval powerful starburst and AGN activity during the lifetimes of the most massive galaxies are predicted by various models of galaxy formation and evolution. In spite of their recurrence and high luminosity, such events are rarely observed. Finding such systems, understanding their nature, and constraining their number density can provide key constraints to galaxy evolutionary models and insights into the interplay between starburst and AGN activities. Methods: We report the discovery of two sources at z=3.867 and z=3.427 that exhibit both powerful starburst and AGN activities. They benefit from multi-wavelength data from radio to X rays from the CFHTLS-D1/SWIRE/XMDS surveys. Follow-up optical and near-infrared spectroscopy, and millimeter IRAM/MAMBO observations are also available. We performed a multi-wavelength analysis of their spectral energy distributions with the aim of understanding the origin of their emission and constraining their luminosities. A comparison with other composite systems at similar redshifts from the literature is also presented. Results: The AGN and starburst bolometric luminosities are 1013 L⊙. The AGN emission dominates at X ray, optical, mid-infrared wavelengths, and probably also in the radio. The starburst emission dominates in the far-infrared. The estimated star formation rates range from 500 to 3000 M⊙/yr. The AGN near-infrared and X ray emissions are heavily obscured in both sources with an estimated dust extinction {A_V} ≥ 4, and Compton-thick gas column densities. The two sources are the most obscured and most luminous AGNs detected at millimeter wavelengths currently known. Conclusions: The sources presented in this work are heavily obscured QSOs, but their properties are not fully explained by the standard AGN unification model. In one source, the ultraviolet and optical spectra suggest the presence of outflowing gas and shocks, and both sources show emission from hot dust, most likely in the

  15. Reducing Cloud Obscuration of MODIS Snow Cover Products Using Information from the Repetitive Patterns of Snow Distribution and Ablation

    NASA Astrophysics Data System (ADS)

    Arogundade, A. B.; Qualls, R. J.

    2012-12-01

    Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover products have been used successfully and are still appealing for variety of hydrological applications owing to their high spatial and temporal resolution; however, cloud obscuration remains their major limitation. On the other hand, several researchers have observed that snow accumulation and ablation occur in reasonably regular patterns from one year to the next. Thus, information from satellite imagery across different years ought to be able to inform the spatial distribution of snow in one year based on information in another to circumvent the cloud obscuration problem. This is a vital piece of information which has not yet been fully recognized or exploited. In this study we utilized a collection of snow cover maps produced from MODIS data across multiple years (2001 to 2011) coupled with the melt-out date of a collection of Snowpack Telemetry (SNOTEL) stations within a region of study to synthesize the regular pattern of snow depletion from the beginning to the end of melt seasons. The synthesized spatial time series are used as a template to determine what condition for cloud obscured areas, snow or no snow, ought to be expected, given the spatial pattern of snow cover on the visible portions of the image in comparison to the synthesized template. The accuracy of this method is evaluated over a basin located in Western Wyoming, in the United States. The results indicate that this method, though simple, is tremendously efficient in cloud reduction and removal and confirm the year to year similarity in the pattern of snow distribution and ablation.

  16. The Role of Molecular Gas in Obscuring Seyfert Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Hicks, E. K. S.; Davies, R. I.; Malkan, M. A.; Genzel, R.; Tacconi, L. J.; Müller Sánchez, F.; Sternberg, A.

    2009-05-01

    In a sample of local active galactic nuclei (AGNs) studied at a spatial resolution on the order of 10 pc, we show that the interstellar medium traced by the molecular hydrogen ν = 1-0 S(1) line at 2.1 μm forms a geometrically thick, clumpy disk. The kinematics of the molecular gas reveals general rotation, although an additional significant component of random bulk motion is required by the high local velocity dispersion. The size scale of the typical gas disk is found to have a radius of ~30 pc with a comparable vertical height. Within this radius, the average gas mass is estimated to be ~107 M sun based on a typical gas mass fraction of 10%, which suggests column densities of N H ~ 5 × 1023 cm-2. Extinction of the stellar continuum within this same region suggests lower column densities of N H ~2 × 1022 cm-2, indicating that the gas distribution on these scales is dominated by dense clumps. In half of the observed Seyfert galaxies, this lower column density is still great enough to obscure the AGN at optical/infrared wavelengths. We conclude, based on the spatial distribution, kinematics, and column densities that the molecular gas observed is spatially mixed with the nuclear stellar population and is likely to be associated with the outer extent of any smaller scale nuclear obscuring structure. Furthermore, we find that the velocity dispersion of the molecular gas is correlated with the star formation rate per unit area, suggesting a link between the two phenomena, and that the gas surface density follows known "Schmidt-Kennicutt" relations. The molecular/dusty structure on these scales may be dynamic since it is possible that the velocity dispersion of the gas, and hence the vertical disk height, is maintained by a short, massive inflow of material into the nuclear region and/or by intense, short-lived nuclear star formation. Based on observations at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of

  17. Obscuration, orientation, and the infrared properties of radio-loud active galaxies

    NASA Technical Reports Server (NTRS)

    Heckman, Timothy M.; O'Dea, Christopher P.; Baum, Stefi A.; Laurikainen, Eija

    1994-01-01

    We report on a study of the mid- and far-infrared (MFIR) properties of several different classes of radio-loud active galactic nuclei (AGNs) using the IRAS database. Our goal is to try to improve the understanding of the possible relationships between the diverse classes of AGNs. The MFIR and radio properties of radio-loud AGNs are especially useful in this regard, since (excluding the blazar class, which we do not study here) the radio emission is thought to be emitted isotropically, and the radio and MFIR radiation should be much less affected by dust obscuration than radiation at shorter wavelengths. We have first compared samples of 3CR broad-line radio galaxies (BLRGs) and narrow-line radio galaxies (NLRGs) matched in radio flux and mean redshift. We find that the BLRGs are stronger than the NLRGs by a factor of 4-5 in their mid-IR emission but are similar to the NLRGs in the far-IR. This is qualitatively consistent with recent 'unification' models for NLRGs and BLRGs which invoke thermal MFIR emission from dusty 'obscuring tori,' but there may be an additional source of far-IR emission present in the more luminous broad-line objects (the radio-loud quasars) studied previously by Heckman, Chambers & Postman (1992). We have also compared samples of Fanaroff-Riley class I (FRI) and Fanaroff-Riley class II (FRII) radio galaxies matched in radio flux and redshift. The FRII galaxies are stronger MFIR emitters than the FRI galaxies by a factor of about 4. This is consistent with suggestions that the central engine in FRI galaxies produces relatively little radiant energy per unit jet power (expecially since we find that the weak MFIR emission from the FRI galaxies may not be powered by the AGN). Comparing samples of gigahertz-peaked spectrum (GPS) and compact steep spectrum (CSS) sources versus non-GPS-CSS sources, we find that the GPS-CSS and non-GPS-CSS sources have similar MFIR strengths. This suggests that the efficiency of the conversion of jet kinetic energy

  18. The fill-in effect in serial recall can be obscured by omission errors.

    PubMed

    Osth, Adam F; Dennis, Simon

    2015-09-01

    Henson (1996) provided a number of demonstrations of error patterns in serial recall that contradict chaining models. Chaining models predict that when participants erroneously recall an item too early, recall should proceed from the point of error. In contradiction to such a prediction, Henson found evidence for a fill-in effect: participants were much more likely to revisit an erroneously skipped item than to continue onward to later list items. However, recent reanalyses of serial recall data sets have found evidence for the opposite pattern in serial recall experiments that use open sets of items. We tested the hypothesis that open sets of items produce fill-in effects by comparing serial recall with an open set and a closed set, and when participants were allowed and prohibited from skipping over responses, and comparing serial recall with a reconstruction of order task. Fill-in effects were observed in all cases except when participants were not encouraged to skip over responses. Subsequent analyses indicated that when omission rates were equated, a fill-in effect was observed for all conditions when lists contained no omissions. These results suggest that high omission rates in open-set designs obscure a fill-in effect and further sound a cautionary note about interpreting cases in which recall continues in the forward direction after a skipped response.

  19. Environmental and health effects review for obscurant graphite flakes. Final report, 1991 July--1993 May

    SciTech Connect

    Driver, C.J.; Ligotke, M.W.; Landis, W.G.; Downs, J.L.; Tiller, B.L.; Moore, E.B. Jr.; Cataldo, D.A.

    1993-07-01

    The health and environmental effects of obscurant graphite flakes were reviewed and compared to predicted levels of graphite flake material in the field during typical testing and training scenarios. Graphite flake dispersion and deposition for simulated mechanical and pyrotechnic releases were determined using a modified Gaussian atmospheric plume-dispersion model. The potential for wind resuspension of graphite flakes is controlled by weathering processes and incorporation rates in soil. Chemically, graphite flakes pose little risk to aquatic or terrestrial systems. Mechanical damage to plants and invertebrate and vertebrate organisms from the flakes is also minimal. In humans, the pathological and physiological response to inhaled graphite flake is similar to that induced by nuisance dusts and cause only transient pulmonary changes. Repeated exposure to very high concentrations (such as those near the source generator) may overwhelm the clearance mechanisms of the lung and result in pulmonary damage from the retained particles in unprotected individuals. However, these lesions either resolve with time or are of limited severity. Health effects of mixed aerosols of mixed aerosols of graphite and fog oil are similar to those produced by graphite flakes alone. Environmental impacts of fog oil-coated graphite flakes are not well known.

  20. CONSTRAINTS ON OBSCURED STAR FORMATION IN HOST GALAXIES OF GAMMA-RAY BURSTS

    SciTech Connect

    Hatsukade, Bunyo; Ohta, Kouji; Hashimoto, Tetsuya; Nakanishi, Kouichiro; Tamura, Yoichi; Kohno, Kotaro

    2012-04-01

    We present the results of the 16 cm wave band continuum observations of four host galaxies of gamma-ray bursts (GRBs) 990705, 021211, 041006, and 051022 using the Australia Telescope Compact Array. Radio emission was not detected in any of the host galaxies. The 2{sigma} upper limits on star formation rates derived from the radio observations of the host galaxies are 23, 45, 27, and 26 M{sub Sun} yr{sup -1}, respectively, which are less than about 10 times those derived from UV/optical observations, suggesting that they have no significant dust-obscured star formation. GRBs 021211 and 051022 are known as the so-called dark GRBs and our results imply that dark GRBs do not always occur in galaxies enshrouded by dust. Because large dust extinction was not observed in the afterglow of GRB 021211, our result suggests the possibility that the cause of the dark GRB is the intrinsic faintness of the optical afterglow. On the other hand, by considering the high column density observed in the afterglow of GRB 051022, the likely cause of the dark GRB is the dust extinction in the line of sight of the GRB.

  1. Host galaxy colour gradients and accretion disc obscuration in AEGIS z ~ 1 X-ray-selected active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Pierce, C. M.; Lotz, J. M.; Salim, S.; Laird, E. S.; Coil, A. L.; Bundy, K.; Willmer, C. N. A.; Rosario, D. J. V.; Primack, J. R.; Faber, S. M.

    2010-10-01

    We describe the effect of active galactic nucleus (AGN) light on host galaxy optical and UV-optical colours, as determined from X-ray-selected AGN host galaxies at z ~ 1, and compare the AGN host galaxy colours to those of a control sample matched to the AGN sample in both redshift and stellar mass. We identify as X-ray-selected AGNs 8.7+4-3 per cent of the red-sequence control galaxies, 9.8 +/- 3 per cent of the blue-cloud control galaxies and 14.7+4-3 per cent of the green-valley control galaxies. The nuclear colours of AGN hosts are generally bluer than their outer colours, while the control galaxies exhibit redder nuclei. AGNs in blue-cloud host galaxies experience less X-ray obscuration, while AGNs in red-sequence hosts have more, which is the reverse of what is expected from general considerations of the interstellar medium. Outer and integrated colours of AGN hosts generally agree with the control galaxies, regardless of X-ray obscuration, but the nuclear colours of unobscured AGNs are typically much bluer, especially for X-ray luminous objects. Visible point sources are seen in many of these, indicating that the nuclear colours have been contaminated by AGN light and that obscuration of the X-ray radiation and visible light are therefore highly correlated. Red AGN hosts are typically slightly bluer than red-sequence control galaxies, which suggests that their stellar populations are slightly younger. We compare these colour data to current models of AGN formation. The unexpected trend of less X-ray obscuration in blue-cloud galaxies and more in red-sequence galaxies is problematic for all AGN feedback models, in which gas and dust is thought to be removed as star formation shuts down. A second class of models involving radiative instabilities in hot gas is more promising for red-sequence AGNs but predicts a larger number of point sources in red-sequence AGNs than is observed. Regardless, it appears that multiple AGN models are necessary to explain the

  2. LLRV flight #1-16-61F with Bell 47 Helicopter providing chase support.

    NASA Technical Reports Server (NTRS)

    1965-01-01

    LLRV flight #1-16-61F with Bell 47 Helicopter providing chase support. The use of chase planes was a critical part of flight research well before the establishment of what was then called the NACA Muroc Flight Test Unit in September 1947 (now the NASA Dryden Flight Research Center). They act as a second set of eyes for the research pilot, warning him of any problems. When test flights of the LLRV began in October 1964, chase support for the vehicle was supplied by a Bell 47 helicopter. It could hover close by, providing information such as altitude and descent rate. LLRV test operations were phased out in late 1966 and early 1967. When Apollo planning was underway in 1960, NASA was looking for a simulator to profile the descent to the moon's surface. Three concepts surfaced: an electronic simulator, a tethered device, and the ambitious Dryden contribution, a free-flying vehicle. All three became serious projects, but eventually the NASA Flight Research Center's (FRC) Lunar Landing Research Vehicle (LLRV) became the most significant one. After conceptual planning and meetings with engineers from Bell Aerosystems Company, Buffalo, N.Y., NASA FRC issued a $3.6 million production contract awarded in 1963, for delivery of the first of two vehicles for flight studies. Built of tubular aluminum alloy like a giant four-legged bedstead, the vehicle was to simulate a lunar landing profile from around 1500 feet to the moon's surface. The LLRV had a turbofan engine mounted vertically in a gimbal, with 4200 pounds of thrust. The engine, lifted the vehicle up to the test altitude and was then throttled back to support five-sixths of the vehicle's weight, thus simulating the reduced gravity of the moon. Two lift rockets with thrust that could be varied from 100 to 500 pounds handled the LLRV's rate of descent and horizontal translations. Sixteen smaller rockets, mounted in pairs, gave the pilot control in pitch, yaw, and roll. The pilot's platform extended forward between two

  3. A Vicious Cycle: A Cross-Sectional Study of Canine Tail-Chasing and Human Responses to It, Using a Free Video-Sharing Website

    PubMed Central

    Burn, Charlotte C.

    2011-01-01

    Tail-chasing is widely celebrated as normal canine behaviour in cultural references. However, all previous scientific studies of tail-chasing or ‘spinning’ have comprised small clinical populations of dogs with neurological, compulsive or other pathological conditions; most were ultimately euthanased. Thus, there is great disparity between scientific and public information on tail-chasing. I gathered data on the first large (n = 400), non-clinical tail-chasing population, made possible through a vast, free, online video repository, YouTube™. The demographics of this online population are described and discussed. Approximately one third of tail-chasing dogs showed clinical signs, including habitual (daily or ‘all the time’) or perseverative (difficult to distract) performance of the behaviour. These signs were observed across diverse breeds. Clinical signs appeared virtually unrecognised by the video owners and commenting viewers; laughter was recorded in 55% of videos, encouragement in 43%, and the commonest viewer descriptors were that the behaviour was ‘funny’ (46%) or ‘cute’ (42%). Habitual tail-chasers had 6.5+/−2.3 times the odds of being described as ‘Stupid’ than other dogs, and perseverative dogs were 6.8+/−2.1 times more frequently described as ‘Funny’ than distractible ones were. Compared with breed- and age-matched control videos, tail-chasing videos were significantly more often indoors and with a computer/television screen switched on. These findings highlight that tail-chasing is sometimes pathological, but can remain untreated, or even be encouraged, because of an assumption that it is ‘normal’ dog behaviour. The enormous viewing figures that YouTube™ attracts (mean+/−s.e. = 863+/−197 viewings per tail-chasing video) suggest that this perception will be further reinforced, without effective intervention. PMID:22096487

  4. Performance of an electro-optical solar compass in partially obscured Sun conditions.

    PubMed

    Bollanti, S; De Meis, D; Di Lazzaro, P; Flora, F; Gallerano, G P; Mezi, L; Murra, D; Vicca, D

    2016-04-20

    Solar compasses are designed to accurately find true North on sunny days. However, no data on their performance are available when sunlight is partially blocked, e.g., by a cloud. We have measured, for the first time to the best of our knowledge, the performance of one of the most accurate electro-optical solar compasses (accuracy better than 0.01  deg) as a function of the solar disk obscuration during the Sun's eclipse on 20 March 2015. The measurements show that the accuracy level is mainly dependent on the asymmetry of the obscuration with respect to the main axis of the optical detection system and, to a lesser extent, on the percentage of the solar disk covered. In particular, azimuth measurement suffered a maximum deviation of 0.08 deg when 35% of the solar disk was asymmetrically obscured. The deviation was smaller when 46% of the solar disk was more symmetrically obscured. This experiment demonstrates that, even in the case of a partially obscured Sun, the electro-optical solar compass maintains an accuracy better than magnetic and electronic compasses. PMID:27140077

  5. Performance of an electro-optical solar compass in partially obscured Sun conditions.

    PubMed

    Bollanti, S; De Meis, D; Di Lazzaro, P; Flora, F; Gallerano, G P; Mezi, L; Murra, D; Vicca, D

    2016-04-20

    Solar compasses are designed to accurately find true North on sunny days. However, no data on their performance are available when sunlight is partially blocked, e.g., by a cloud. We have measured, for the first time to the best of our knowledge, the performance of one of the most accurate electro-optical solar compasses (accuracy better than 0.01  deg) as a function of the solar disk obscuration during the Sun's eclipse on 20 March 2015. The measurements show that the accuracy level is mainly dependent on the asymmetry of the obscuration with respect to the main axis of the optical detection system and, to a lesser extent, on the percentage of the solar disk covered. In particular, azimuth measurement suffered a maximum deviation of 0.08 deg when 35% of the solar disk was asymmetrically obscured. The deviation was smaller when 46% of the solar disk was more symmetrically obscured. This experiment demonstrates that, even in the case of a partially obscured Sun, the electro-optical solar compass maintains an accuracy better than magnetic and electronic compasses.

  6. Fusion of lidar and radar for detection of partially obscured objects

    NASA Astrophysics Data System (ADS)

    Hollinger, Jim; Kutscher, Brett; Close, Ryan

    2015-05-01

    The capability to detect partially obscured objects is of interest to many communities, including ground vehicle robotics. The ability to find partially obscured objects can aid in automated navigation and planning algorithms used by robots. Two sensors often used for this task are Lidar and Radar. Lidar and Radar systems provide complementary data about the environment. Both are active sensing modalities and provide direct range measurements. However, they operate in very different portions of the radio frequency spectrum. By exploiting properties associated with the different frequency spectra, the sensors are able to compensate for each other's shortcomings. This makes them excellent candidates for sensor processing and data fusion systems. The benefits associated with Lidar and Radar sensor fusion for a ground vehicle application, using economical variants of these sensors, are presented. Special consideration is given to detecting objects partially obscured by light to medium vegetation.

  7. OBSCURING FRACTION OF ACTIVE GALACTIC NUCLEI: IMPLICATIONS FROM RADIATION-DRIVEN FOUNTAIN MODELS

    SciTech Connect

    Wada, Keiichi

    2015-10-10

    Active galactic nuclei (AGNs) are believed to be obscured by an optical thick “torus” that covers a large fraction of solid angles for the nuclei. However, the physical origin of the tori and the differences in the tori among AGNs are not clear. In a previous paper based on three-dimensional radiation-hydorodynamic calculations, we proposed a physics-based mechanism for the obscuration, called “radiation-driven fountains,” in which the circulation of the gas driven by central radiation naturally forms a thick disk that partially obscures the nuclear emission. Here, we expand this mechanism and conduct a series of simulations to explore how obscuration depends on the properties of AGNs. We found that the obscuring fraction f{sub obs} for a given column density toward the AGNs changes depending on both the AGN luminosity and the black hole mass. In particular, f{sub obs} for N{sub H} ≥ 10{sup 22} cm{sup −2} increases from ∼0.2 to ∼0.6 as a function of the X-ray luminosity L{sub X} in the L{sub X} = 10{sup 42–44} erg s{sup −1} range, but f{sub obs} becomes small (∼0.4) above a luminosity (∼10{sup 45} erg s{sup −1}). The behaviors of f{sub obs} can be understood by a simple analytic model and provide insight into the redshift evolution of the obscuration. The simulations also show that for a given L{sub AGN}, f{sub obs} is always smaller (∼0.2–0.3) for a larger column density (N{sub H} ≥ 10{sup 23} cm{sup −2}). We also found cases that more than 70% of the solid angles can be covered by the fountain flows.

  8. Obscuring Fraction of Active Galactic Nuclei: Implications from Radiation-driven Fountain Models

    NASA Astrophysics Data System (ADS)

    Wada, Keiichi

    2015-10-01

    Active galactic nuclei (AGNs) are believed to be obscured by an optical thick “torus” that covers a large fraction of solid angles for the nuclei. However, the physical origin of the tori and the differences in the tori among AGNs are not clear. In a previous paper based on three-dimensional radiation-hydorodynamic calculations, we proposed a physics-based mechanism for the obscuration, called “radiation-driven fountains,” in which the circulation of the gas driven by central radiation naturally forms a thick disk that partially obscures the nuclear emission. Here, we expand this mechanism and conduct a series of simulations to explore how obscuration depends on the properties of AGNs. We found that the obscuring fraction fobs for a given column density toward the AGNs changes depending on both the AGN luminosity and the black hole mass. In particular, fobs for NH ≥ 1022 cm‑2 increases from ∼0.2 to ∼0.6 as a function of the X-ray luminosity LX in the LX = 1042–44 erg s‑1 range, but fobs becomes small (∼0.4) above a luminosity (∼1045 erg s‑1). The behaviors of fobs can be understood by a simple analytic model and provide insight into the redshift evolution of the obscuration. The simulations also show that for a given LAGN, fobs is always smaller (∼0.2–0.3) for a larger column density (NH ≥ 1023 cm‑2). We also found cases that more than 70% of the solid angles can be covered by the fountain flows.

  9. Coevolutionary chase in two-species systems with applications to mimicry.

    PubMed

    Gavrilets, S; Hastings, A

    1998-04-21

    We study a general dynamical model describing coevolution of two haploid populations with two alleles at a single locus under weak linear symmetric frequency-dependent selection. A novel and more realistic element of our modeling approach is that both species are allowed to evolve. We analyse conditions for "evolutionary chase" between two phenotypically similar species in which one species evolves to decrease its resemblance with the other species while this other species evolves to increase its resemblance with the first species. We apply our results to a series of simple population genetics models describing classical Müllerian and Batesian mimicries as well as intermediate cases. We show that one of the most important factors influencing the plausibility of non-equilibrium dynamics in systems of mimicry is the relationship between the strength of between-species and within-species interactions. This indicates that this relationship should be the focus of both experimental and theoretical work. Our results suggest that systematic studies of frequencies of different mimicry morphs through time may be very useful.

  10. Is There an Obscured AGN in the Normal Galaxy IRASF01063-8034

    NASA Technical Reports Server (NTRS)

    Greenhill, Lincoln J.

    2005-01-01

    The XMM target for this program is ostensibly a "normal" galaxy, but the presence of water maser emission indicated that it may be an obscured AGN. Our primary goal is to test this hypothesis; detection hard X-ray emission and a reflection-dominated spectrum would indicate an AGN is present. Demonstration that the local universe contains obscured AGN is important to constraining models of the hard cosmic X-ray background, as is identification of efficient methods to locate them (e.g., ground-based detection of maser emission at microwave frequencies).

  11. Does lateral transmission obscure inheritance in hunter-gatherer languages?

    PubMed

    Bowern, Claire; Epps, Patience; Gray, Russell; Hill, Jane; Hunley, Keith; McConvell, Patrick; Zentz, Jason

    2011-01-01

    In recent years, linguists have begun to increasingly rely on quantitative phylogenetic approaches to examine language evolution. Some linguists have questioned the suitability of phylogenetic approaches on the grounds that linguistic evolution is largely reticulate due to extensive lateral transmission, or borrowing, among languages. The problem may be particularly pronounced in hunter-gatherer languages, where the conventional wisdom among many linguists is that lexical borrowing rates are so high that tree building approaches cannot provide meaningful insights into evolutionary processes. However, this claim has never been systematically evaluated, in large part because suitable data were unavailable. In addition, little is known about the subsistence, demographic, ecological, and social factors that might mediate variation in rates of borrowing among languages. Here, we evaluate these claims with a large sample of hunter-gatherer languages from three regions around the world. In this study, a list of 204 basic vocabulary items was collected for 122 hunter-gatherer and small-scale cultivator languages from three ecologically diverse case study areas: northern Australia, northwest Amazonia, and California and the Great Basin. Words were rigorously coded for etymological (inheritance) status, and loan rates were calculated. Loan rate variability was examined with respect to language area, subsistence mode, and population size, density, and mobility; these results were then compared to the sample of 41 primarily agriculturalist languages. Though loan levels varied both within and among regions, they were generally low in all regions (mean 5.06%, median 2.49%, and SD 7.56), despite substantial demographic, ecological, and social variation. Amazonian levels were uniformly very low, with no language exhibiting more than 4%. Rates were low but more variable in the other two study regions, in part because of several outlier languages where rates of borrowing were

  12. Does Lateral Transmission Obscure Inheritance in Hunter-Gatherer Languages?

    PubMed Central

    Bowern, Claire; Epps, Patience; Gray, Russell; Hill, Jane; Hunley, Keith; McConvell, Patrick; Zentz, Jason

    2011-01-01

    In recent years, linguists have begun to increasingly rely on quantitative phylogenetic approaches to examine language evolution. Some linguists have questioned the suitability of phylogenetic approaches on the grounds that linguistic evolution is largely reticulate due to extensive lateral transmission, or borrowing, among languages. The problem may be particularly pronounced in hunter-gatherer languages, where the conventional wisdom among many linguists is that lexical borrowing rates are so high that tree building approaches cannot provide meaningful insights into evolutionary processes. However, this claim has never been systematically evaluated, in large part because suitable data were unavailable. In addition, little is known about the subsistence, demographic, ecological, and social factors that might mediate variation in rates of borrowing among languages. Here, we evaluate these claims with a large sample of hunter-gatherer languages from three regions around the world. In this study, a list of 204 basic vocabulary items was collected for 122 hunter-gatherer and small-scale cultivator languages from three ecologically diverse case study areas: northern Australia, northwest Amazonia, and California and the Great Basin. Words were rigorously coded for etymological (inheritance) status, and loan rates were calculated. Loan rate variability was examined with respect to language area, subsistence mode, and population size, density, and mobility; these results were then compared to the sample of 41 primarily agriculturalist languages in [1]. Though loan levels varied both within and among regions, they were generally low in all regions (mean 5.06%, median 2.49%, and SD 7.56), despite substantial demographic, ecological, and social variation. Amazonian levels were uniformly very low, with no language exhibiting more than 4%. Rates were low but more variable in the other two study regions, in part because of several outlier languages where rates of borrowing were

  13. Hubble Space Telescope Morphologies of z ~ 2 Dust Obscured Galaxies. I. Power-Law Sources

    NASA Astrophysics Data System (ADS)

    Bussmann, R. S.; Dey, Arjun; Lotz, J.; Armus, L.; Brand, K.; Brown, M. J. I.; Desai, V.; Eisenhardt, P.; Higdon, J.; Higdon, S.; Jannuzi, B. T.; Le Floc'h, E.; Melbourne, J.; Soifer, B. T.; Weedman, D.

    2009-03-01

    We present high-spatial resolution optical and near-infrared imaging obtained using the ACS, WFPC2, and NICMOS cameras aboard the Hubble Space Telescope of 31 24 μm bright z ≈ 2 Dust Obscured Galaxies (DOGs) identified in the Boötes Field of the NOAO Deep Wide-Field Survey. Although this subset of DOGs have mid-IR spectral energy distributions dominated by a power-law component suggestive of an AGN, all but one of the galaxies are spatially extended and not dominated by an unresolved component at rest-frame UV or optical wavelengths. The observed V - H and I-H colors of the extended components are 0.2-3 magnitudes redder than normal star-forming galaxies. All but one have axial ratios >0.3, making it unlikely that DOGs are composed of an edge-on star-forming disk. We model the spatially extended component of the surface brightness distributions of the DOGs with a Sérsic profile and find effective radii of 1-6 kpc. This sample of DOGs is smaller than most submillimeter galaxies (SMGs), but larger than quiescent high-redshift galaxies. Nonparametric measures (Gini and M20) of DOG morphologies suggest that these galaxies are more dynamically relaxed than local ULIRGs. We estimate lower limits to the stellar masses of DOGs based on the rest-frame optical photometry and find that these range from ~109-1011 M sun. If major mergers are the progenitors of DOGs, then these observations suggest that DOGs may represent a postmerger evolutionary stage.

  14. Radio Jet Feedback and Star Formation in Heavily Obscured, Hyperluminous Quasars at Redshifts ∼ 0.5–3. I. ALMA Observations

    NASA Astrophysics Data System (ADS)

    Lonsdale, Carol J.; Lacy, M.; Kimball, A. E.; Blain, A.; Whittle, M.; Wilkes, B.; Stern, D.; Condon, J.; Kim, M.; Assef, R. J.; Tsai, C.-W.; Efstathiou, A.; Jones, S.; Eisenhardt, P.; Bridge, C.; Wu, J.; Lonsdale, Colin J.; Jones, K.; Jarrett, T.; Smith, R.

    2015-11-01

    We present Atacama Large Millimeter/submillimeter Array (ALMA) 870 μm (345 GHz) data for 49 high-redshift (0.47 < z < 2.85), luminous (11.7\\lt {log}({L}{{bol}}/{L}ȯ )\\lt 14.2) radio-powerful active galactic nuclei (AGNs), obtained to constrain cool dust emission from starbursts concurrent with highly obscured radiative-mode black hole (BH) accretion in massive galaxies that possess a small radio jet. The sample was selected from the Wide-field Infrared Survey Explorer with extremely steep (red) mid-infrared colors and with compact radio emission from NVSS/FIRST. Twenty-six sources are detected at 870 μm, and we find that the sample has large mid- to far-infrared luminosity ratios, consistent with a dominant and highly obscured quasar. The rest-frame 3 GHz radio powers are 24.7\\lt {log}({P}\\text{3.0 GHz}/{{{W}} {Hz}}-1)\\lt 27.3, and all sources are radio-intermediate or radio-loud. BH mass estimates are 7.7 < log(MBH/M⊙) < 10.2. The rest-frame 1–5 μm spectral energy distributions are very similar to the “Hot DOGs” (hot dust-obscured galaxies), and steeper (redder) than almost any other known extragalactic sources. ISM masses estimated for the ALMA-detected sources are 9.9 < log (MISM/M⊙) < 11.75 assuming a dust temperature of 30 K. The cool dust emission is consistent with star formation rates reaching several thousand M⊙ yr‑1, depending on the assumed dust temperature, but we cannot rule out the alternative that the AGN powers all the emission in some cases. Our best constrained source has radiative transfer solutions with approximately equal contributions from an obscured AGN and a young (10–15 Myr) compact starburst.

  15. Radio Jet Feedback and Star Formation in Heavily Obscured, Hyperluminous Quasars at Redshifts ˜ 0.5-3. I. ALMA Observations

    NASA Astrophysics Data System (ADS)

    Lonsdale, Carol J.; Lacy, M.; Kimball, A. E.; Blain, A.; Whittle, M.; Wilkes, B.; Stern, D.; Condon, J.; Kim, M.; Assef, R. J.; Tsai, C.-W.; Efstathiou, A.; Jones, S.; Eisenhardt, P.; Bridge, C.; Wu, J.; Lonsdale, Colin J.; Jones, K.; Jarrett, T.; Smith, R.

    2015-11-01

    We present Atacama Large Millimeter/submillimeter Array (ALMA) 870 μm (345 GHz) data for 49 high-redshift (0.47 < z < 2.85), luminous (11.7\\lt {log}({L}{{bol}}/{L}⊙ )\\lt 14.2) radio-powerful active galactic nuclei (AGNs), obtained to constrain cool dust emission from starbursts concurrent with highly obscured radiative-mode black hole (BH) accretion in massive galaxies that possess a small radio jet. The sample was selected from the Wide-field Infrared Survey Explorer with extremely steep (red) mid-infrared colors and with compact radio emission from NVSS/FIRST. Twenty-six sources are detected at 870 μm, and we find that the sample has large mid- to far-infrared luminosity ratios, consistent with a dominant and highly obscured quasar. The rest-frame 3 GHz radio powers are 24.7\\lt {log}({P}\\text{3.0 GHz}/{{{W}} {Hz}}-1)\\lt 27.3, and all sources are radio-intermediate or radio-loud. BH mass estimates are 7.7 < log(MBH/M⊙) < 10.2. The rest-frame 1-5 μm spectral energy distributions are very similar to the “Hot DOGs” (hot dust-obscured galaxies), and steeper (redder) than almost any other known extragalactic sources. ISM masses estimated for the ALMA-detected sources are 9.9 < log (MISM/M⊙) < 11.75 assuming a dust temperature of 30 K. The cool dust emission is consistent with star formation rates reaching several thousand M⊙ yr-1, depending on the assumed dust temperature, but we cannot rule out the alternative that the AGN powers all the emission in some cases. Our best constrained source has radiative transfer solutions with approximately equal contributions from an obscured AGN and a young (10-15 Myr) compact starburst.

  16. Edgar Allan Poe: a case description of the Marfan syndrome in an obscure short story.

    PubMed

    Battle, Robert W

    2011-07-01

    In the obscure short story “A Tale of the Ragged Mountains,” Edgar Allen Poe meticulously described a character with features remarkably consistent with the Marfan syndrome. This description appeared in fiction >50 years before the celebrated index description in the published medical research by Professor Antoine Marfan in Paris in 1896.

  17. AGN Obscuration Through Dusty Infrared Dominated Flows. 1; Radiation-Hydrodynamics Solution for the Wind

    NASA Technical Reports Server (NTRS)

    Dorodnitsyn, A.; Bisnovatyi-Kogan. G. S.; Kallman, T.

    2011-01-01

    We construct a radiation-hydrodynamics model for the obscuring toroidal structure in active galactic nuclei. In this model the obscuration is produced at parsec scale by a dense, dusty wind which is supported by infrared radiation pressure on dust grains. To find the distribution of radiation pressure, we numerically solve the 2D radiation transfer problem in a flux limited diffusion approximation. We iteratively couple the solution with calculations of stationary 1D models for the wind, and obtain the z-component of the velocity. Our results demonstrate that for AGN luminosities greater than 0.1 L(sub edd) external illumination can support a geometrically thick obscuration via outflows driven by infrared radiation pressure. The terminal velocity of marginally Compton-thin models (0.2 < tau(sub T) < 0.6), is comparable to or greater than the escape velocity. In Compton thick models the maximum value of the vertical component of the velocity is lower than the escape velocity, suggesting that a significant part of our torus is in the form of failed wind. The results demonstrate that obscuration via normal or failed infrared-driven winds is a viable option for the AGN torus problem and AGN unification models. Such winds can also provide an important channel for AGN feedback.

  18. Critical evaluation of the Obscure Figures Test as an instrument for measuring "cognitive innovation".

    PubMed

    Voss, H G; Keller, H

    1977-10-01

    The Obscure Figure Test has been conceptualized by Acker and McReynolds (1965) as a measure of Cognitive Innovation. As a general concept Cognitive Innovation refers to an integration of different kinds of behavioral systems, e.g., creativity and exploratory behavior. Considering recent research about the relationship between curiosity and creativity as well as basic assumptions underlying this test, it is hypothesized that this is an instrument for measuring creativity rather than curiosity. 41 boys and 41 girls ranging from 7 to 10 yr. of age were given a battery of tests of curiosity and creativity. There were significant correlations between Obscure Figures Test and creativity measures. No such relationships were found between obscure figures and curiosity measures. A factor analysis yielded two factors which could be interpreted as "visual exploration" and "creativity", the obscure figures being a marker variable on the latter factor. Results are discussed in terms of the theoretical assumptions underlying the concepts of curiosity, creativity, and Cognitive Innovation. Further implications with respect to the requirements for an operationalization of Cognitive Innovations are mentioned.

  19. NuSTAR observations of heavily obscured quasars at z ∼ 0.5

    SciTech Connect

    Lansbury, G. B.; Alexander, D. M.; Moro, A. Del; Gandhi, P.; Aird, J.; Assef, R. J.; Stern, D.; Ballantyne, D. R.; Baloković, M.; Grefenstette, B. W.; Harrison, F. A.; Bauer, F. E.; Boggs, S. E.; Brandt, W. N.; Christensen, F. E.; Craig, W. W.; Elvis, M.; Hailey, C. J.; Hickox, R. C.; Koss, M.; and others

    2014-04-10

    We present NuSTAR hard X-ray observations of three Type 2 quasars at z ≈ 0.4-0.5, optically selected from the Sloan Digital Sky Survey. Although the quasars show evidence for being heavily obscured, Compton-thick systems on the basis of the 2-10 keV to [O III] luminosity ratio and multiwavelength diagnostics, their X-ray absorbing column densities (N {sub H}) are poorly known. In this analysis, (1) we study X-ray emission at >10 keV, where X-rays from the central black hole are relatively unabsorbed, in order to better constrain N {sub H}. (2) We further characterize the physical properties of the sources through broad-band near-UV to mid-IR spectral energy distribution analyses. One of the quasars is detected with NuSTAR at >8 keV with a no-source probability of <0.1%, and its X-ray band ratio suggests near Compton-thick absorption with N {sub H} ≳ 5 × 10{sup 23} cm{sup –2}. The other two quasars are undetected, and have low X-ray to mid-IR luminosity ratios in both the low-energy (2-10 keV) and high-energy (10-40 keV) X-ray regimes that are consistent with extreme, Compton-thick absorption (N {sub H} ≳ 10{sup 24} cm{sup –2}). We find that for quasars at z ∼ 0.5, NuSTAR provides a significant improvement compared to lower energy (<10 keV) Chandra and XMM-Newton observations alone, as higher column densities can now be directly constrained.

  20. Obscuring Torus Geometry from the NuSTAR Survey of Swift/BAT AGN

    NASA Astrophysics Data System (ADS)

    Balokovic, Mislav; Harrison, Fiona; NuSTAR

    2016-06-01

    The Nuclear Spectroscopic Telescope Array (NuSTAR) has enabled studies of the local active galactic nuclei (AGN) to extend into the spectral window above 10 keV with unprecedented spatial resolution and two orders of magnitude better sensitivity than any other instrument operating in that energy range. As a part of its long-term extragalactic program NuSTAR is surveying the nearby population of AGN detected at hard X-ray energies by the Swift Burst Alert Telescope (Swift/BAT). I will present spectroscopic results based on NuSTAR and Swift observations of ~150 Swift/BAT AGN surveyed in the first three years of NuSTAR operation. This sample forms an atlas of the highest quality hard X-ray spectra available to date for a large number of AGN, providing unprecedented insight into the variety AGN spectra in the hard X-ray band. In addition to phenomenology, which is an essential ingredient of Cosmic X-ray Background studies, it is possible to use new fitting models to directly probe the geometry of the toroidal obscurer (torus). Its main spectral features lie within the NuSTAR bandpass, making it possible to test the common assumption that a similar Compton-thick torus exists around essentially every Seyfert-type AGN. I will discuss torus geometry constraints based on the X-ray spectra in relation to those from other wavelengths, the effects on interpretation of high-redshift AGN observations, and the limitations of the current results.

  1. The nature of the dense obscuring material in the nucleus of NGC 1068

    NASA Technical Reports Server (NTRS)

    Tacconi, L. J.; Genzel, R.; Blietz, M.; Cameron, M.; Harris, A. I.; Madden, S.

    1994-01-01

    High spatial and spectral resolution observations of the distribution, physical parameters, and kinematics of the molecular interstellar medium toward the nucleus of the Seyfert 2 galaxy NGC 1068 are reported. The data consist of 2.4 by 3.4 arcseconds resolution interferometry of the 88.6 GHz HCN J = 1 towards 0 line at 17 km/s spectral resolution, single dish observations of several mm/submm isotopic lines of CO and HCN, and 0.85 arcseconds imaging spectroscopy of the 2.12 micron H2 S(1) line at a velocity resolution of 110 km/s. The central few hundred parsecs of NGC 1068 contain a system of dense (N(H2) approximately 10(exp 5) cm(exp -3)), warm (T greater than or equal to 70 K) molecular cloud cores. The low density molecular envelopes have probably been stripped by the nuclear wind and radiation. The molecular gas layer is located in the plane of NGC 1068's large scale disk (inclination approximately 35 deg) and orbits in elliptical streamlines in response to the central stellar bar. The spatial distribution of the 2 micron H2 emission suggests that gas is shocked at the leading edge of the bar, probably resulting in gas influx into the central 100 pc at a rate of a few solar mass per year. In addition to large scale streaming (with a solid body rotation curve), the HCN velocity field requires the presence of random motions of order 100 km/s. We interpret these large random motions as implying the nuclear gas disk to be very thick (scale height/radius approximately 1), probably as the result of the impact of nuclear radiation and wind on orbiting molecular clouds. Geometry and column density of the molecular cloud layer between approximately 30 pc to 300 pc from the nucleus can plausibly account for the nuclear obscuration and anisotropy of the radiation field in the visible and UV.

  2. Imaging through obscurations for sluicing operations in the waste storage tanks

    SciTech Connect

    Peters, T.J.; McMakin, D.L.; Sheen, D.M.; Chieda, M.A.

    1994-08-01

    Waste remediators have identified that surveillance of waste remediation operations and periodic inspections of stored waste are required under very demanding and difficult viewing environments. In many cases, obscurants such as dust or water vapor are generated as part of the remediation activity. Methods are required for viewing or imaging beyond the normal visual spectrum. Work space images guide the movement of remediation equipment, creating a need for rapidly updated, near real-time imaging capability. In addition, there is a need for three-dimensional topographical data to determine the contours of the wastes, to plan retrieval campaigns, and to provide a three-dimensional map of a robot`s work space as basis for collision avoidance. Three basic imaging techniques were evaluated: optical, acoustic and radar. The optical imaging methods that were examined used cameras which operated in the visible region and near-infrared region and infrared cameras which operated in the 3--5 micron and 8--12 micron wavelength regions. Various passive and active lighting schemes were tested, as well as the use of filters to eliminate reflection in the visible region. Image enhancement software was used to extend the range where visual techniques could be used. In addition, the operation of a laser range finder, which operated at 0.835 microns, was tested when fog/water droplets were suspended in the air. The acoustic technique involved using commercial acoustic sensors, operating at approximately 50 kHz and 215 kHz, to determine the attenuation of the acoustic beam in a high-humidity environment. The radar imaging methods involved performing millimeter wave (94 GHz) attenuation measurement sin the various simulated sluicing environments and performing preliminary experimental imaging studies using a W-Band (75--110 GHz) linearly scanned transceiver in a laboratory environment. The results of the tests are discussed.

  3. NuSTAR Observations of Heavily Obscured Quasars at z Is Approximately 0.5

    NASA Technical Reports Server (NTRS)

    Lansbury, G. B.; Alexander, D. M.; Del Moro, A.; Gandhi, P.; Assef, R. J.; Stern, D.; Aird, J.; Ballantyne, D. R.; Balokovic, M.; Bauer, F. E.; Boggs, S. E.; Brandt, W. N.; Christensen, F. E.; Craig, W. W.; Elvis, M.; Grefenstette, B. W.; Hailey, C. J.; Harrison, F. A.; Hickox, R. C.; Koss, M.; LaMassa, S. M.; Luo, B.; Mullaney, J. R.; Teng, S. H.; Urry, C. M.; Zhang, W. W.

    2014-01-01

    We present NuSTAR hard X-ray observations of three Type 2 quasars at z approx. = 0.4-0.5, optically selected from the Sloan Digital Sky Survey. Although the quasars show evidence for being heavily obscured, Compton-thick systems on the basis of the 2-10 keV to [O(sub III)] luminosity ratio and multiwavelength diagnostics, their X-ray absorbing column densities (N(sub H)) are poorly known. In this analysis, (1) we study X-ray emission at greater than 10 keV, where X-rays from the central black hole are relatively unabsorbed, in order to better constrain N(sub H). (2) We further characterize the physical properties of the sources through broad-band near-UV to mid-IR spectral energy distribution analyses. One of the quasars is detected with NuSTAR at greater than 8 keV with a no-source probability of less than 0.1%, and its X-ray band ratio suggests near Compton-thick absorption with N(sub H) is approximately greater than 5 × 10(exp 23) cm(exp -2). The other two quasars are undetected, and have low X-ray to mid-IR luminosity ratios in both the low-energy (2-10 keV) and high-energy (10-40 keV) X-ray regimes that are consistent with extreme, Compton-thick absorption (N(sub H) is approximately greater than 10(exp 24) cm(exp -2)). We find that for quasars at z is approximately 0.5, NuSTAR provides a significant improvement compared to lower energy (less than 10 keV) Chandra and XMM-Newton observations alone, as higher column densities can now be directly constrained.

  4. Transitory O-rich chemistry in heavily obscured C-rich post-AGB stars

    NASA Astrophysics Data System (ADS)

    García-Hernández, D. A.; García-Lario, P.; Cernicharo, J.; Engels, D.; Perea-Calderón, J. V.

    2016-07-01

    Spitzer/IRS spectra of eleven heavily obscured C-rich sources rapidly evolving from asymptotic giant branch (AGB) stars to Planetary Nebulae are presented. IRAM 30m observations for three of these post-AGBs are also reported. A few (3) of these sources are known to exhibit strongly variable maser emission of O-bearing molecules such as OH and H2 O, suggesting a transitory O-rich chemistry because of the quickly changing physical and chemical conditions in this short evolutionary phase. Interestingly, the Spitzer/IRS spectra show a rich circumstellar carbon chemistry, as revealed by the detection of small hydrocarbon molecules such as C2H2, C4H2, C6H2, C6H6, and HCN. Benzene is detected towards two sources, bringing up to three the total number of Galactic post-AGBs where this molecule has been detected. In addition, we report evidence for the possible detection of other hydrocarbon molecules like HC3N, CH3C2H, and CH3 in several of these sources. The available IRAM 30m data confirm that the central stars are C-rich - in despite of the presence of O-rich masers - and the presence of high velocity molecular outflows together with extreme AGB mass-loss rates (∼⃒10-4 Mʘ /yr). Our observations confirm the polymerization model of Cernicharo [1] that predicts a rich photochemistry in the neutral regions of these objects on timescales shorter than the dynamical evolution of the central HII region, leading to the formation of small C-rich molecules and a transitory O-rich chemistry.

  5. HUBBLE SPACE TELESCOPE MORPHOLOGIES OF z {approx} 2 DUST-OBSCURED GALAXIES. II. BUMP SOURCES

    SciTech Connect

    Bussmann, R. S.; Dey, Arjun; Lotz, J.; Jannuzi, B. T.; Armus, L.; Desai, V.; Soifer, B. T.; Brown, M. J. I.; Eisenhardt, P.; Higdon, J.; Higdon, S.; Le Floc'h, E.; Melbourne, J.; Weedman, D.

    2011-05-20

    We present Hubble Space Telescope imaging of 22 ultra-luminous infrared galaxies (ULIRGs) at z {approx} 2 with extremely red R - [24] colors (called dust-obscured galaxies, or DOGs) which have a local maximum in their spectral energy distribution (SED) at rest-frame 1.6 {mu}m associated with stellar emission. These sources, which we call 'bump DOGs', have star formation rates (SFRs) of 400-4000 M{sub sun} yr{sup -1} and have redshifts derived from mid-IR spectra which show strong polycyclic aromatic hydrocarbon emission-a sign of vigorous ongoing star formation. Using a uniform morphological analysis, we look for quantifiable differences between bump DOGs, power-law DOGs (Spitzer-selected ULIRGs with mid-IR SEDs dominated by a power law and spectral features that are more typical of obscured active galactic nuclei than starbursts), submillimeter-selected galaxies, and other less-reddened ULIRGs from the Spitzer Extragalactic First Look Survey. Bump DOGs are larger than power-law DOGs (median Petrosian radius of 8.4 {+-} 2.7 kpc versus 5.5 {+-} 2.3 kpc) and exhibit more diffuse and irregular morphologies (median M{sub 20} of -1.08 {+-} 0.05 versus -1.48 {+-} 0.05). These trends are qualitatively consistent with expectations from simulations of major mergers in which merging systems during the peak SFR period evolve from M{sub 20} = -1.0 to M{sub 20} = -1.7. Less-obscured ULIRGs (i.e., non-DOGs) tend to have more regular, centrally peaked, single-object morphologies rather than diffuse and irregular morphologies. This distinction in morphologies may imply that less-obscured ULIRGs sample the merger near the end of the peak SFR period. Alternatively, it may indicate that the intense star formation in these less-obscured ULIRGs is not the result of a recent major merger.

  6. Hubble Space Telescope Morphologies of z ~ 2 Dust-obscured Galaxies. II. Bump Sources

    NASA Astrophysics Data System (ADS)

    Bussmann, R. S.; Dey, Arjun; Lotz, J.; Armus, L.; Brown, M. J. I.; Desai, V.; Eisenhardt, P.; Higdon, J.; Higdon, S.; Jannuzi, B. T.; Le Floc'h, E.; Melbourne, J.; Soifer, B. T.; Weedman, D.

    2011-05-01

    We present Hubble Space Telescope imaging of 22 ultra-luminous infrared galaxies (ULIRGs) at z ≈ 2 with extremely red R - [24] colors (called dust-obscured galaxies, or DOGs) which have a local maximum in their spectral energy distribution (SED) at rest-frame 1.6 μm associated with stellar emission. These sources, which we call "bump DOGs," have star formation rates (SFRs) of 400-4000 M sun yr-1 and have redshifts derived from mid-IR spectra which show strong polycyclic aromatic hydrocarbon emission—a sign of vigorous ongoing star formation. Using a uniform morphological analysis, we look for quantifiable differences between bump DOGs, power-law DOGs (Spitzer-selected ULIRGs with mid-IR SEDs dominated by a power law and spectral features that are more typical of obscured active galactic nuclei than starbursts), submillimeter-selected galaxies, and other less-reddened ULIRGs from the Spitzer Extragalactic First Look Survey. Bump DOGs are larger than power-law DOGs (median Petrosian radius of 8.4 ± 2.7 kpc versus 5.5 ± 2.3 kpc) and exhibit more diffuse and irregular morphologies (median M 20 of -1.08 ± 0.05 versus -1.48 ± 0.05). These trends are qualitatively consistent with expectations from simulations of major mergers in which merging systems during the peak SFR period evolve from M 20 = -1.0 to M 20 = -1.7. Less-obscured ULIRGs (i.e., non-DOGs) tend to have more regular, centrally peaked, single-object morphologies rather than diffuse and irregular morphologies. This distinction in morphologies may imply that less-obscured ULIRGs sample the merger near the end of the peak SFR period. Alternatively, it may indicate that the intense star formation in these less-obscured ULIRGs is not the result of a recent major merger.

  7. COMPARING ULTRAVIOLET- AND INFRARED-SELECTED STARBURST GALAXIES IN DUST OBSCURATION AND LUMINOSITY

    SciTech Connect

    Sargsyan, Lusine A.; Weedman, Daniel W.; Houck, James R. E-mail: dweedman@isc.astro.cornell.ed

    2010-06-01

    We present samples of starburst galaxies that represent the extremes discovered with infrared and ultraviolet observations, including 25 Markarian galaxies, 23 ultraviolet-luminous galaxies discovered with GALEX, and the 50 starburst galaxies having the largest infrared/ultraviolet ratios. These sources have z < 0.5 and cover a luminosity range of {approx}10{sup 4}. Comparisons between infrared luminosities determined with the 7.7 {mu}m polycyclic aromatic hydrocarbon feature and ultraviolet luminosities from the stellar continuum at 153 nm are used to determine obscuration in starbursts and dependence of this obscuration on infrared or ultraviolet luminosity. A strong selection effect arises for the ultraviolet-selected samples: the brightest sources appear bright because they have the least obscuration. Obscuration correction for the ultraviolet-selected Markarian+GALEX sample has the form log[UV(intrinsic)/UV(observed)] = 0.07({+-}0.04)M(UV) + 2.09 {+-} 0.69 but for the full infrared-selected Spitzer sample is log[UV(intrinsic)/UV(observed)] = 0.17({+-}0.02)M(UV) + 4.55 {+-} 0.4. The relation of total bolometric luminosity L {sub ir} to M(UV) is also determined for infrared-selected and ultraviolet-selected samples. For ultraviolet-selected galaxies, log L {sub ir} = -(0.33 {+-} 0.04)M(UV) + 4.52 {+-} 0.69. For the full infrared-selected sample, log L {sub ir} = -(0.23 {+-} 0.02)M(UV) + 6.99 {+-} 0.41, all for L {sub ir} in L{sub sun} and M(UV) the AB magnitude at rest frame 153 nm. These results imply that obscuration corrections by factors of 2-3 determined from reddening of the ultraviolet continuum for Lyman break galaxies with z>2 are insufficient, and should be at least a factor of 10 for M(UV) {approx} -17, with decreasing correction for more luminous sources.

  8. Infrared Spectral Energy Distribution Decomposition of WISE-selected, Hyperluminous Hot Dust-obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Fan, Lulu; Han, Yunkun; Nikutta, Robert; Drouart, Guillaume; Knudsen, Kirsten K.

    2016-06-01

    We utilize a Bayesian approach to fit the observed mid-IR-to-submillimeter/millimeter spectral energy distributions (SEDs) of 22 WISE-selected and submillimeter-detected, hyperluminous hot dust-obscured galaxies (Hot DOGs), with spectroscopic redshift ranging from 1.7 to 4.6. We compare the Bayesian evidence of a torus plusgraybody (Torus+GB) model with that of a torus-only (Torus) model and find that the Torus+GB model has higher Bayesian evidence for all 22 Hot DOGs than the torus-only model, which presents strong evidence in favor of the Torus+GB model. By adopting the Torus+GB model, we decompose the observed IR SEDs of Hot DOGs into torus and cold dust components. The main results are as follows. (1) Hot DOGs in our submillimeter-detected sample are hyperluminous ({L}{IR}≥slant {10}13{L}ȯ ), with torus emission dominating the IR energy output. However, cold dust emission is non-negligible, contributing on average ˜ 24% of total IR luminosity. (2) Compared to QSO and starburst SED templates, the median SED of Hot DOGs shows the highest luminosity ratio between mid-IR and submillimeter at rest frame, while it is very similar to that of QSOs at ˜ 10{--}50 μ {{m}}, suggesting that the heating sources of Hot DOGs should be buried AGNs. (3) Hot DOGs have high dust temperatures ({T}{dust}˜ 72 K) and high IR luminosity of cold dust. The {T}{dust}{--}{L}{IR} relation of Hot DOGs suggests that the increase in IR luminosity for Hot DOGs is mostly due to the increase of the dust temperature, rather than dust mass. Hot DOGs have lower dust masses than submillimeter galaxies (SMGs) and QSOs within a similar redshift range. Both high IR luminosity of cold dust and relatively low dust mass in Hot DOGs can be expected by their relatively high dust temperatures. (4) Hot DOGs have high dust-covering factors (CFs), which deviate from the previously proposed trend of the dust CF decreasing with increasing bolometric luminosity. Finally, we can reproduce the observed

  9. Infrared Spectral Energy Distribution Decomposition of WISE-selected, Hyperluminous Hot Dust-obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Fan, Lulu; Han, Yunkun; Nikutta, Robert; Drouart, Guillaume; Knudsen, Kirsten K.

    2016-06-01

    We utilize a Bayesian approach to fit the observed mid-IR-to-submillimeter/millimeter spectral energy distributions (SEDs) of 22 WISE-selected and submillimeter-detected, hyperluminous hot dust-obscured galaxies (Hot DOGs), with spectroscopic redshift ranging from 1.7 to 4.6. We compare the Bayesian evidence of a torus plusgraybody (Torus+GB) model with that of a torus-only (Torus) model and find that the Torus+GB model has higher Bayesian evidence for all 22 Hot DOGs than the torus-only model, which presents strong evidence in favor of the Torus+GB model. By adopting the Torus+GB model, we decompose the observed IR SEDs of Hot DOGs into torus and cold dust components. The main results are as follows. (1) Hot DOGs in our submillimeter-detected sample are hyperluminous ({L}{IR}≥slant {10}13{L}⊙ ), with torus emission dominating the IR energy output. However, cold dust emission is non-negligible, contributing on average ˜ 24% of total IR luminosity. (2) Compared to QSO and starburst SED templates, the median SED of Hot DOGs shows the highest luminosity ratio between mid-IR and submillimeter at rest frame, while it is very similar to that of QSOs at ˜ 10{--}50 μ {{m}}, suggesting that the heating sources of Hot DOGs should be buried AGNs. (3) Hot DOGs have high dust temperatures ({T}{dust}˜ 72 K) and high IR luminosity of cold dust. The {T}{dust}{--}{L}{IR} relation of Hot DOGs suggests that the increase in IR luminosity for Hot DOGs is mostly due to the increase of the dust temperature, rather than dust mass. Hot DOGs have lower dust masses than submillimeter galaxies (SMGs) and QSOs within a similar redshift range. Both high IR luminosity of cold dust and relatively low dust mass in Hot DOGs can be expected by their relatively high dust temperatures. (4) Hot DOGs have high dust-covering factors (CFs), which deviate from the previously proposed trend of the dust CF decreasing with increasing bolometric luminosity. Finally, we can reproduce the observed

  10. Black carbon, particle number concentration and nitrogen oxide emission factors of random in-use vehicles measured with the on-road chasing method

    NASA Astrophysics Data System (ADS)

    Ježek, I.; Katrašnik, T.; Westerdahl, D.; Močnik, G.

    2015-10-01

    The chasing method was used in an on-road measurement campaign, and emission factors (EF) of black carbon (BC), particle number (PN) and nitrogen oxides (NOx) were determined for 139 individual vehicles of different types encountered on the roads. The aggregated results provide EFs for BC, NOx and PN for three vehicle categories: goods vehicles, gasoline and diesel passenger cars. This is the first on-road measurement study where BC EFs of numerous individual diesel cars were determined in real-world driving conditions. We found good agreement between EFs of goods vehicles determined in this campaign and the results of previous studies that used either chasing or remote-sensing measurement techniques. The composition of the sampled car fleet determined from the national vehicle registry information is reflective of Eurostat statistical data on the Slovenian and European vehicle fleet. The median BC EF of diesel and gasoline cars that were in use for less than 5 years decreased by 60 and 47 % from those in use for 5-10 years, respectively; the median NOx and PN EFs of goods vehicles that were in use for less than 5 years decreased from those in use for 5-10 years by 52 and 67 %, respectively. Surprisingly, we found an increase of BC EFs in the newer goods vehicle fleet compared to the 5-10-year old one. The influence of engine maximum power of the measured EFs showed an increase in NOx EF from least to more powerful vehicles with diesel engines. Finally, a disproportionate contribution of high emitters to the total emissions of the measured fleet was found; the top 25 % of emitting diesel cars contributed 63, 47 and 61 % of BC, NOx and PN emissions respectively. With the combination of relatively simple on-road measurements and sophisticated post processing, individual vehicle EF can be determined and useful information about the fleet emissions can be obtained by exactly representing vehicles which contribute disproportionally to vehicle fleet emissions; and

  11. Changes in the 14C-Labeled Cell Wall Components with Chase Time after Incorporation of UDP[14C]Glucose by Intact Cotton Fibers 1

    PubMed Central

    Dugger, W. M.; Palmer, Raymond L.

    1988-01-01

    Intact, in vitro-grown cotton fibers will incorporate [14C]glucose from externally supplied UDP[14C]glucose into a variety of cell wall components including cellulose; this labeled fraction will continue to increase up to 4 hours chase time. In the fraction soluble in hot water there was no significant change in total label; however, the largest fraction after the 30 minute pulse with UDP[14C]glucose was chloroform-methanol soluble (70%) and showed a significant decrease with chase. The lipids that make up about 85% of this fraction were identified by TLC as steryl glucosides, acylated steryl glucosides, and glucosyl-phosphoryl-polyprenol. Following the pulse, the loss of label from acylated steryl glucosides and glucosylphophoryl-polyprenol was almost complete within 2 hours of chase; steryl glucosides made up about 85% of the fraction at that chase time. The total loss in the lipid fraction (about 100 picomoles per milligram dry weight of fiber) with chase times of 4 hours approximates the total gain in the total glucans. PMID:16666066

  12. High Power Cryogenic Targets

    SciTech Connect

    Gregory Smith

    2011-08-01

    The development of high power cryogenic targets for use in parity violating electron scattering has been a crucial ingredient in the success of those experiments. As we chase the precision frontier, the demands and requirements for these targets have grown accordingly. We discuss the state of the art, and describe recent developments and strategies in the design of the next generation of these targets.

  13. DETECTION OF THE INTERMEDIATE-WIDTH EMISSION LINE REGION IN QUASAR OI 287 WITH THE BROAD EMISSION LINE REGION OBSCURED BY THE DUSTY TORUS

    SciTech Connect

    Li, Zhenzhen; Zhou, Hongyan; Wang, Huiyuan; Liu, Bo; Liu, Wen-Juan; Pan, Xiang; Jiang, Peng; Hao, Lei; Ji, Tuo; Shi, Xiheng; Zhang, Shaohua E-mail: zhouhongyan@pric.org.cn

    2015-10-20

    The existence of intermediate-width emission line regions (IELRs) in active galactic nuclei has been discussed for over two decades. A consensus, however, is yet to be arrived at due to the lack of convincing evidence for their detection. We present a detailed analysis of the broadband spectrophotometry of the partially obscured quasar OI 287. The ultraviolet intermediate-width emission lines (IELs) are very prominent, in high contrast to the corresponding broad emission lines (BELs) which are heavily suppressed by dust reddening. Assuming that the IELR is virialized, we estimated its distance to the central black hole to be ∼2.9 pc, similar to the dust sublimation radius of ∼1.3 pc. Photo-ionization calculations suggest that the IELR has a hydrogen density of ∼10{sup 8.8}–10{sup 9.4} cm{sup −3}, within the range of values quoted for the dusty torus near the sublimation radius. Both its inferred location and physical conditions suggest that the IELR originates from the inner surface of the dusty torus. In the spectrum of this quasar, we identified only one narrow absorption-line system associated with the dusty material. With the aid of photo-ionization model calculations, we found that the obscuring material might originate from an outer region of the dusty torus. We speculate that the dusty torus, which is exposed to the central ionizing source, may produce IELs through photo-ionization processes, as well as obscure BELs as a natural “coronagraph.” Such a “coronagraph” could be found in a large number of partially obscured quasars and may be a useful tool to study IELRs.

  14. A population of massive, luminous galaxies hosting heavily dust-obscured gamma-ray bursts: Implications for the use of GRBs as tracers of cosmic star formation

    SciTech Connect

    Perley, D. A.; Levan, A. J.; Tanvir, N. R.; Cenko, S. B.; Bloom, J. S.; Filippenko, A. V.; Morgan, A. N.; Hjorth, J.; Krühler, T.; Fynbo, J. P. U.; Milvang-Jensen, B.; Fruchter, A.; Kalirai, J.; Jakobsson, P.; Prochaska, J. X.

    2013-12-01

    We present observations and analysis of the host galaxies of 23 heavily dust-obscured gamma-ray bursts (GRBs) observed by the Swift satellite during the years 2005-2009, representing all GRBs with an unambiguous host-frame extinction of A{sub V} > 1 mag from this period. Deep observations with Keck, Gemini, Very Large Telescope, Hubble Space Telescope, and Spitzer successfully detect the host galaxies and establish spectroscopic or photometric redshifts for all 23 events, enabling us to provide measurements of the intrinsic host star formation rates, stellar masses, and mean extinctions. Compared to the hosts of unobscured GRBs at similar redshifts, we find that the hosts of dust-obscured GRBs are (on average) more massive by about an order of magnitude and also more rapidly star forming and dust obscured. While this demonstrates that GRBs populate all types of star-forming galaxies, including the most massive, luminous systems at z ≈ 2, at redshifts below 1.5 the overall GRB population continues to show a highly significant aversion to massive galaxies and a preference for low-mass systems relative to what would be expected given a purely star-formation-rate-selected galaxy sample. This supports the notion that the GRB rate is strongly dependent on metallicity, and may suggest that the most massive galaxies in the universe underwent a transition in their chemical properties ∼9 Gyr ago. We also conclude that, based on the absence of unobscured GRBs in massive galaxies and the absence of obscured GRBs in low-mass galaxies, the dust distributions of the lowest-mass and the highest-mass galaxies are relatively homogeneous, while intermediate-mass galaxies (∼10{sup 9} M {sub ☉}) have diverse internal properties.

  15. ALMA observations of a candidate molecular outflow in an obscured quasar

    SciTech Connect

    Sun, Ai-Lei; Greene, Jenny E.; Zakamska, Nadia L.; Nesvadba, Nicole P. H.

    2014-08-01

    We present Atacama Large Millimeter/Submillimeter Array CO (1-0) and CO (3-2) observations of SDSS J135646.10+102609.0, an obscured quasar and ultra-luminous infrared galaxy with two merging nuclei and a known 20 kpc scale ionized outflow. The total molecular gas mass is M{sub mol}≈9{sub −6}{sup +19}×10{sup 8} M{sub ☉}, mostly distributed in a compact rotating disk at the primary nucleus (M{sub mol} ≈ 3 × 10{sup 8} M{sub ☉}) and an extended tidal arm (M{sub mol} ≈ 5 × 10{sup 8} M{sub ☉}). The tidal arm is one of the most massive molecular tidal features known; we suggest that it is due to the lower chance of shock dissociation in this elliptical/disk galaxy merger. In the spatially resolved CO (3-2) data, we find a compact (r ≈ 0.3 kpc) high-velocity (v ≈ 500 km s{sup –1}) redshifted feature in addition to the rotation at the N nucleus. We propose a molecular outflow as the most likely explanation for the high-velocity gas. The outflowing mass of M{sub mol} ≈ 7 × 10{sup 7} M{sub ☉} and the short dynamical time of t{sub dyn} ≈ 0.6 Myr yield a very high outflow rate of M-dot{sub mol}≈350 M{sub ☉} yr{sup –1} and can deplete the gas in a million years. We find a low star formation rate (<16 M{sub ☉} yr{sup –1} from the molecular content and <21 M{sub ☉} yr{sup –1} from the far-infrared spectral energy distribution decomposition) that is inadequate to supply the kinetic luminosity of the outflow ( E-dot ≈3×10{sup 43} erg s{sup –1}). Therefore, the active galactic nucleus (AGN), with a bolometric luminosity of 10{sup 46} erg s{sup –1}, likely powers the outflow. The momentum boost rate of the outflow ( p-dot /(L{sub bol}/c)≈3) is lower than typical molecular outflows associated with AGNs, which may be related to its compactness. The molecular and ionized outflows are likely two distinct bursts induced by episodic AGN activity which varies on a timescale of 10{sup 7} yr.

  16. A pulse-chase strategy combining click-EdU and photoconvertible fluorescent reporter: tracking Golgi protein dynamics during the cell cycle.

    PubMed

    Bourge, Mickaël; Fort, Cécile; Soler, Marie-Noëlle; Satiat-Jeunemaître, Béatrice; Brown, Spencer C

    2015-01-01

    Imaging or quantifying protein synthesis in cellulo through a well-resolved analysis of the cell cycle (also defining G1 subcompartments) is a methodological challenge. Click chemistry is the method of choice to reveal the thymidine analogue 5-ethynyl-2'-deoxyuridine (EdU) and track proliferating nuclei undergoing DNA synthesis. However, the click reaction quenches fluorescent proteins. Our challenge was to reconcile these two tools. A robust protocol based on a high-resolution cytometric cell cycle analysis in tobacco (Nicotiana tabacum) BY2 cells expressing fluorescent Golgi markers has been established. This was broadly applicable to tissues, cell clusters, and other eukaryotic material, and compatible with Scale clearing. EdU was then used with the photoconvertible protein sialyl transferase (ST)-Kaede as a Golgi marker in a photoconversion pulse-chase cytometric configuration resolving, in addition, subcompartments of G1. Quantitative restoration of protein fluorescence was achieved by introducing acidic EDTA washes to strip the copper from these proteins which were then imaged at neutral pH. The rate of synthesis of this Golgi membrane marker was low during early G1, but in the second half of G1 (30% of cycle duration) much of the synthesis occurred. Marker synthesis then persisted during S and G2. These insights into Golgi biology are discussed in terms of the cell's ability to adapt exocytosis to cell growth needs.

  17. Detection of foliage-obscured vehicle using a multiwavelength polarimetric lidar

    USGS Publications Warehouse

    Tan, S.; Stoker, J.; Greenlee, S.

    2008-01-01

    Foliage obscured man-made targets detection and identification is of great interest to many applications. In this paper, the backscattered laser signals from a multiwavelength polarimetric lidar were used to detect a vehicle hidden inside a vegetated area. The Polarimetric reflectance data from the lidar at two separate laser wavelengths at 1064 nm and 532 nm revealed distinct target characteristics from both the vehicle and the vegetation. The results from this case study demonstrated the validity of the proposed lidar detection technique. Furthermore, the results could potentially lead to a lidar detection and identification technique for a wide variety of foliage-obscured man-made targets under various application scenarios. ?? 2007 IEEE.

  18. Effects of atmospheric and man-made obscurants on visual contrast

    NASA Astrophysics Data System (ADS)

    Shirkey, R. C.

    1981-01-01

    Features of the Army-developed electrooptical systems atmospheric effects library for direct quantification of the alteration of optical radiation due to atmospheric conditions or obscurants are described. Data have been cataloged regarding the propagation of radiation through different types of clouds, dust, gases, precipitation events, and chemical smoke. The propagation of UV, visible, near-, mid-, and far-IR portions of the spectrum, as well as 53 laser lines and the 10-350 GHz region has been characterized. Performance degradation is coded in ANSII FORTRAN and stored in the modular library memory. A quantitative formula defines the apparent contrast between a target and background, with consideration of the contributions of scattered and reflected radiation. Meteorological and obscurant data can be input, together with the radiation used, to determine the probability of detecting a target. It is noted that the sensitivity of optical detection is strongly dependent on the path angle of the beam.

  19. Search for Obscured Nucleus in a Luminous IRAS Galaxy NGC 6240

    NASA Technical Reports Server (NTRS)

    Leighly, Karen

    1999-01-01

    IRAS discovered very luminous objects which emit the vast majority of their radiation in the infrared wavelength. The energy source of such a tremendous amount of emission is not understood. Starburst and active galactic nuclei (AGN) are thought to be the origin of their power. X-ray observations are expected to be able to reveal the characteristics of the AGN component. However, some are very X-ray quiet, because the AGN is thought to be obscured by a large column density. In order to determine the primary luminosity of the nucleus, we need an X-ray observation with a wide energy band at least up to several tens of keV. We propose to observe NGC 6240, one of the luminous IRAS galaxies, to investigate the characteristics of its AGN, which must be obscured by large column density.

  20. AGN Obscuration Through Dusty Infrared Dominated Flows. II. Multidimensional, Radiation-Hydrodynamics Modeling

    NASA Technical Reports Server (NTRS)

    Dorodnitsyn, Anton; Kallman, Tim; Bisno\\vatyiI-Kogan, Gennadyi

    2011-01-01

    We explore a detailed model in which the active galactic nucleus (AGN) obscuration results from the extinction of AGN radiation in a global ow driven by the pressure of infrared radiation on dust grains. We assume that external illumination by UV and soft X-rays of the dusty gas located at approximately 1pc away from the supermassive black hole is followed by a conversion of such radiation into IR. Using 2.5D, time-dependent radiation hydrodynamics simulations in a ux-limited di usion approximation we nd that the external illumination can support a geometrically thick obscuration via out ows driven by infrared radiation pressure in AGN with luminosities greater than 0:05 L(sub edd) and Compton optical depth, Tau(sub T) approx > & 1.

  1. Searching for heavily obscured post-AGB stars and planetary nebulae. II. Near-IR observations of IRAS sources

    NASA Astrophysics Data System (ADS)

    Ramos-Larios, G.; Guerrero, M. A.; Suárez, O.; Miranda, L. F.; Gómez, J. F.

    2012-09-01

    The most massive AGB stars are expected to result in heavily obscured post-AGB stars, proto-PNe and PNe with highly axisymmetric morphologies. To investigate this evolutionary connection, we have selected a sample of 165 presumably obscured IRAS post-AGB star and PN candidates and obtained near-IR JHK images for 164 of them. These images, in conjunction with DSS, 2MASS, Spitzer GLIMPSE, MSX, AKARI, and IRAS archival data, have allowed us to identify the near-IR counterparts of 154 of these sources, providing reliable finding charts and coordinates. Near-IR narrow-band Brγ, H2, and K continuum images were acquired for 6 of these sources that were found to be resolved in near-IR JHK images. Among the extended post-AGB source and PN candidates, three are round and seven have bipolar morphologies. Five of the extended sources are ionized and may have thus entered the PN stage. We note that all extended sources with water maser emission have bipolar morphology. We have investigated the Galactic distribution of sources with the largest flux drop from the 9 μm AKARI band to the near-IR J band and found that the width of the distribution in Galactic latitude is consistent with those of bipolar PNe and DUPLEX (DUst-Prominent Longitudinally EXtended) sources. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile (081.D-0812), observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, and on observations with AKARI, a JAXA project with the participation of ESA.

  2. Continuing challenges in the diagnosis and management of obscure gastrointestinal bleeding

    PubMed Central

    Baptista, Veronica; Marya, Neil; Singh, Anupam; Rupawala, Abbas; Gondal, Bilal; Cave, David

    2014-01-01

    The diagnosis and management of obscure gastrointestinal bleeding (OGIB) have changed dramatically since the introduction of video capsule endoscopy (VCE) followed by deep enteroscopy and other imaging technologies in the last decade. Significant advances have been made, yet there remains room for improvement in our diagnostic yield and treatment capabilities for recurrent OGIB. In this review, we will summarize the latest technologies for the diagnosis of OGIB, limitations of VCE, technological enhancement in VCE, and different management options for OGIB. PMID:25400996

  3. San Pedro Mártir observations of microvariability in obscured quasars

    NASA Astrophysics Data System (ADS)

    Polednikova, J.; Ederoclite, A.; Cepa, J.; de Diego, J. A.; González-Serrano, J. I.; Bongiovanni, A.; Oteo, I.; Pérez García, A. M.; Pérez-Martínez, R.; Pintos-Castro, I.; Ramón-Pérez, M.; Sánchez-Portal, M.

    2015-06-01

    Fast brightness variations are a unique tool to probe the innermost regions of active galactic nuclei (AGN). These variations are called microvariability or intra-night variability, and this phenomenon has been monitored in samples of blazars and unobscured AGNs. Detecting optical microvariations in targets hidden by the obscuring torus is a challenging task because the region responsible for the variations is hidden from our sight. However, there have been reports of fast variations in obscured Seyfert galaxies in X-rays, which rises the question whether microvariations can also be detected in obscured AGNs in the optical regime. Because the expected variations are very small and can easily be lost within the noise, the analysis requires a statistical approach. We report the use of a one-way analysis of variance, ANOVA, with which we searched for microvariability. ANOVA was successfully employed in previous studies of unobscured AGNs. As a result, we found microvariable events during three observing blocks: in two we observed the same object (Mrk 477), and in another, J0759+5050. The results on Mrk 477 confirm previous findings. However, since Mrk 477 is quite a peculiar target with hidden broad-line regions, we cannot rule out the possibility that we have serendipitously chosen a target prone to variations.

  4. Interferometric follow-up of WISE hyper-luminous hot, dust-obscured galaxies

    SciTech Connect

    Wu, Jingwen; Wright, Edward L.; Bussmann, R. Shane; Tsai, Chao-Wei; Eisenhardt, Peter R. M.; Stern, Daniel; Moustakas, Leonidas; Petric, Andreea; Blain, Andrew; Bridge, Carrie R.; Benford, Dominic J.; Assef, Roberto J.; Gelino, Christopher R.

    2014-09-20

    The Wide-field Infrared Survey Explorer (WISE) has discovered an extraordinary population of hyper-luminous dusty galaxies that are faint in the two bluer passbands (3.4 μm and 4.6 μm) but are bright in the two redder passbands of WISE (12 μm and 22 μm). We report on initial follow-up observations of three of these hot, dust-obscured galaxies, or Hot DOGs, using the Combined Array for Research in Millimeter-wave Astronomy and the Submillimeter Array interferometer arrays at submillimeter/millimeter wavelengths. We report continuum detections at ∼1.3 mm of two sources (WISE J014946.17+235014.5 and WISE J223810.20+265319.7, hereafter W0149+2350 and W2238+2653, respectively), and upper limits to CO line emission at 3 mm in the observed frame for two sources (W0149+2350 and WISE J181417.29+341224.8, hereafter W1814+3412). The 1.3 mm continuum images have a resolution of 1''-2'' and are consistent with single point sources. We estimate the masses of cold dust are 2.0 × 10{sup 8} M {sub ☉} for W0149+2350 and 3.9 × 10{sup 8} M {sub ☉} for W2238+2653, comparable to cold dust masses of luminous quasars. We obtain 2σ upper limits to the molecular gas masses traced by CO, which are 3.3 × 10{sup 10} M {sub ☉} and 2.3 × 10{sup 10} M {sub ☉} for W0149+2350 and W1814+3412, respectively. We also present high-resolution, near-IR imaging with the WFC3 on the Hubble Space Telescope for W0149+2653 and with NIRC2 on Keck for W2238+2653. The near-IR images show morphological structure dominated by a single, centrally condensed source with effective radius less than 4 kpc. No signs of gravitational lensing are evident.

  5. GEMINI/GeMS Observations Unveil the Structure of the Heavily Obscured Globular Cluster Liller 1.

    NASA Astrophysics Data System (ADS)

    Saracino, S.; Dalessandro, E.; Ferraro, F. R.; Lanzoni, B.; Geisler, D.; Mauro, F.; Villanova, S.; Moni Bidin, C.; Miocchi, P.; Massari, D.

    2015-06-01

    By exploiting the exceptional high-resolution capabilities of the near-IR camera GSAOI combined with the Gemini Multi-Conjugate Adaptive System at the GEMINI South Telescope, we investigated the structural and physical properties of the heavily obscured globular cluster Liller 1 in the Galactic bulge. We have obtained the deepest and most accurate color–magnitude diagram published so far for this cluster, reaching {{K}s}∼ 19 (below the main-sequence turnoff level). We used these data to redetermine the center of gravity of the system, finding that it is located about 2.″2 southeast from the literature value. We also built new star density and surface brightness profiles for the cluster and rederived its main structural and physical parameters (scale radii, concentration parameter, central mass density, total mass). We find that Liller 1 is significantly less concentrated (concentration parameter c=1.74) and less extended (tidal radius {{r}t}=298\\prime\\prime and core radius {{r}c}=5\\buildrel{\\prime\\prime}\\over{.} 39) than previously thought. By using these newly determined structural parameters, we estimated the mass of Liller 1 to be {{M}tot}=2.3+0.3-0.1× {{10}6} {{M}ȯ } ({{M}tot}=1.5+0.2-0.1× {{10}6} {{M}ȯ } for a Kroupa initial mass function), which is comparable to that of the most massive clusters in the Galaxy (ω Centari and Terzan 5). Also, Liller 1 has the second-highest collision rate (after Terzan 5) among all star clusters in the Galaxy, thus confirming that it is an ideal environment for the formation of collisional objects (such as millisecond pulsars). Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da

  6. Infrared Luminosities and Dust Properties of z ≈ 2 Dust-obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Bussmann, R. S.; Dey, Arjun; Borys, C.; Desai, V.; Jannuzi, B. T.; Le Floc'h, E.; Melbourne, J.; Sheth, K.; Soifer, B. T.

    2009-11-01

    We present SHARC-II 350 μm imaging of twelve 24 μm bright (F 24 μm > 0.8 mJy) Dust-Obscured Galaxies (DOGs) and Combined Array for Research in Millimeter-wave Astronomy (CARMA) 1 mm imaging of a subset of two DOGs. These objects are selected from the Boötes field of the NOAO Deep Wide-Field Survey. Detections of four DOGs at 350 μm imply infrared (IR) luminosities which are consistent to within a factor of 2 of expectations based on a warm-dust spectral energy distribution (SED) scaled to the observed 24 μm flux density. The 350 μm upper limits for the 8 non-detected DOGs are consistent with both Mrk 231 and M82 (warm-dust SEDs), but exclude cold dust (Arp 220) SEDs. The two DOGs targeted at 1 mm were not detected in our CARMA observations, placing strong constraints on the dust temperature: T dust > 35-60 K. Assuming these dust properties apply to the entire sample, we find dust masses of ≈3 × 108 M sun. In comparison to other dusty z ~ 2 galaxy populations such as submillimeter galaxies (SMGs) and other Spitzer-selected high-redshift sources, this sample of DOGs has higher IR luminosities (2 × 1013 L sun versus 6 × 1012 L sun for the other galaxy populations) that are driven by warmer dust temperatures (>35-60 K versus ~30 K) and lower inferred dust masses (3 × 108 M sun versus 3 × 109 M sun). Wide-field Herschel and Submillimeter Common-User Bolometer Array-2 surveys should be able to detect hundreds of these power-law-dominated DOGs. We use the existing Hubble Space Telescope and Spitzer/InfraRed Array Camera data to estimate stellar masses of these sources and find that the stellar to gas mass ratio may be higher in our 24 μm bright sample of DOGs than in SMGs and other Spitzer-selected sources. Although much larger sample sizes are needed to provide a definitive conclusion, the data are consistent with an evolutionary trend in which the formation of massive galaxies at z ~ 2 involves a submillimeter bright, cold-dust, and star

  7. Is there an Obscured AGN in the Normal Galaxy IRASF01063-8034

    NASA Technical Reports Server (NTRS)

    Greenhill, Lincoln J.

    2004-01-01

    The target galactic nucleus is ostensibly "normal," but the presence of water maser emission indicates that it may be an obscured AGN. Our primary goal has been to test this hypothesis through the detection hard X-ray emission and an X-ray spectrum characteristic of heavy absorption. The data for this program became available in May 2003. Light curves show that most of the data are good and that the background was well behaved. We have constructed images and found the X-ray emission in this target is a hard and may be extended. The presence of an AGN has been confirmed through observation with XMM. This is one of many edge-on normal galaxies that may contain AGN. The orientation of the extension will be compared to the structure of molecular gas observed at high angular resolution with VLBI. These radio observations were completed in August 2003. Correlation was completed in late 2003. The data have yet to be delivered by the ATNF. Since the start of the program, we have also obtained six radio spectra, on top of the two obtained at or close to the epoch of discovery for the maser. Early indications were that the maser emission exhibited unusually broad velocity extent and that it "jumped in velocity on time scales of weeks. This behavior has been speculated to be the signature of emission excited by jet-ISM interactions. After more extensive and more sensitive radio study, we find that (1) the emission does not in fact change velocity centroid substantially and (2) it comprises narrower, more "normal" emission features. The joint interpretation of radio and XMM data will be possible once the VLBI images and position-resolved X-ray spectra have been made, probably in summer 2004. If the radio emission arises in an accretion disk, rather than a jet, then we may predict that the VLBI images will exhibit velocity-position gradients orthogonal to the extension of X-ray emission, which presumably traces an optical narrow line or outflow region.

  8. Hybrid electromagnetic models for the purpose of detection and identification of visually obscured targets

    NASA Astrophysics Data System (ADS)

    Dehmollaian, Mojtaba

    This thesis focuses on the application of radio waves for detection and recognition of visually obscured targets. To provide practical solutions, comprehensive forward and inverse models are needed to capture and exploit the physical phenomena involved. These models must accurately simulate wave propagation in the environment in which the target is imbedded, scattering from the target and wave interaction of the medium scatterers and the target. In this dissertation, two problems of major importance are investigated. The first problem is detection of complex targets camouflaged inside forest and the second problem pertains to imaging of building interiors and detection of targets within. In the early chapters, a hybrid target-foliage model is developed to investigate the scattering behavior of hard targets embedded inside a forest canopy. This model is composed of two parts, one for foliage and the other for hard targets. The connection between these two models that accounts for the first-order interaction between the foliage scatterers and the target is accomplished through the application of the reciprocity theorem. The foliage penetration model is based on the coherent single scattering theory, developed previously. The target scattering model is based on either exact numerical finite difference time domain technique or high frequency asymptotic iterative physical optics approximation. Having the hybrid target-foliage model, a polarization synthesis optimization method for improving signal to clutter ratio is presented, using genetic algorithms. In the later chapters, the problem of through-wall imaging using the synthetic aperture radar technique by employing ultra wideband antennas and scanning over a wide range of incidence angles is investigated. Theoretical and experimental studies on the effects of different walls on point target images are carried out and refocusing approaches are introduced to remove the wall effects and restore the image resolution

  9. INFRARED LUMINOSITIES AND DUST PROPERTIES OF z approx 2 DUST-OBSCURED GALAXIES

    SciTech Connect

    Bussmann, R. S.; Dey, Arjun; Jannuzi, B. T.; Borys, C.; Desai, V.; Sheth, K.; Soifer, B. T.; Le Floc'h, E.; Melbourne, J.

    2009-11-01

    We present SHARC-II 350 mum imaging of twelve 24 mum bright (F{sub 24m}u{sub m} > 0.8 mJy) Dust-Obscured Galaxies (DOGs) and Combined Array for Research in Millimeter-wave Astronomy (CARMA) 1 mm imaging of a subset of two DOGs. These objects are selected from the Booetes field of the NOAO Deep Wide-Field Survey. Detections of four DOGs at 350 mum imply infrared (IR) luminosities which are consistent to within a factor of 2 of expectations based on a warm-dust spectral energy distribution (SED) scaled to the observed 24 mum flux density. The 350 mum upper limits for the 8 non-detected DOGs are consistent with both Mrk 231 and M82 (warm-dust SEDs), but exclude cold dust (Arp 220) SEDs. The two DOGs targeted at 1 mm were not detected in our CARMA observations, placing strong constraints on the dust temperature: T{sub dust} > 35-60 K. Assuming these dust properties apply to the entire sample, we find dust masses of approx3 x 10{sup 8} M{sub sun}. In comparison to other dusty z approx 2 galaxy populations such as submillimeter galaxies (SMGs) and other Spitzer-selected high-redshift sources, this sample of DOGs has higher IR luminosities (2 x 10{sup 13} L{sub sun} versus 6 x 10{sup 12} L{sub sun} for the other galaxy populations) that are driven by warmer dust temperatures (>35-60 K versus approx30 K) and lower inferred dust masses (3 x 10{sup 8} M{sub sun} versus 3 x 10{sup 9} M{sub sun}). Wide-field Herschel and Submillimeter Common-User Bolometer Array-2 surveys should be able to detect hundreds of these power-law-dominated DOGs. We use the existing Hubble Space Telescope and Spitzer/InfraRed Array Camera data to estimate stellar masses of these sources and find that the stellar to gas mass ratio may be higher in our 24 mum bright sample of DOGs than in SMGs and other Spitzer-selected sources. Although much larger sample sizes are needed to provide a definitive conclusion, the data are consistent with an evolutionary trend in which the formation of massive galaxies

  10. Interferometric Follow-up of WISE Hyper-luminous Hot, Dust-obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Wu, Jingwen; Bussmann, R. Shane; Tsai, Chao-Wei; Petric, Andreea; Blain, Andrew; Eisenhardt, Peter R. M.; Bridge, Carrie R.; Benford, Dominic J.; Stern, Daniel; Assef, Roberto J.; Gelino, Christopher R.; Moustakas, Leonidas; Wright, Edward L.

    2014-09-01

    The Wide-field Infrared Survey Explorer (WISE) has discovered an extraordinary population of hyper-luminous dusty galaxies that are faint in the two bluer passbands (3.4 μm and 4.6 μm) but are bright in the two redder passbands of WISE (12 μm and 22 μm). We report on initial follow-up observations of three of these hot, dust-obscured galaxies, or Hot DOGs, using the Combined Array for Research in Millimeter-wave Astronomy and the Submillimeter Array interferometer arrays at submillimeter/millimeter wavelengths. We report continuum detections at ~1.3 mm of two sources (WISE J014946.17+235014.5 and WISE J223810.20+265319.7, hereafter W0149+2350 and W2238+2653, respectively), and upper limits to CO line emission at 3 mm in the observed frame for two sources (W0149+2350 and WISE J181417.29+341224.8, hereafter W1814+3412). The 1.3 mm continuum images have a resolution of 1''-2'' and are consistent with single point sources. We estimate the masses of cold dust are 2.0 × 108 M ⊙ for W0149+2350 and 3.9 × 108 M ⊙ for W2238+2653, comparable to cold dust masses of luminous quasars. We obtain 2σ upper limits to the molecular gas masses traced by CO, which are 3.3 × 1010 M ⊙ and 2.3 × 1010 M ⊙ for W0149+2350 and W1814+3412, respectively. We also present high-resolution, near-IR imaging with the WFC3 on the Hubble Space Telescope for W0149+2653 and with NIRC2 on Keck for W2238+2653. The near-IR images show morphological structure dominated by a single, centrally condensed source with effective radius less than 4 kpc. No signs of gravitational lensing are evident.

  11. Remote Optical Imagery of Obscured Objects in Low-Visibility Environments Using Parametric Amplification

    SciTech Connect

    Asher, R.B.; Bliss, D.E.; Cameron, S.M.; Hamil, R.A.

    1998-10-14

    The development of unconventional active optical sensors to remotely detect and spatially resolve suspected threats obscured by low-visibility observation conditions (adverse weather, clouds, dust, smoke, precipitation, etc.) is fundamental to maintaining tactical supremacy in the battlespace. In this report, the authors describe an innovative frequency-agile image intensifier technology based on time-gated optical parametic amplification (OPA) for enhanced light-based remote sensing through pervasive scattering and/or turbulent environments. Improved dynamic range characteristics derived from the amplified passband of the OPA receiver combined with temporal discrimination in the image capture process will offset radiant power extinction losses, while defeating the deugradative effects & multipath dispersion and ,diffuse backscatter noise along the line-of-sight on resultant image contrast and range resolution. Our approach extends the operational utility of the detection channel in existing laser radar systems by increasing sensitivity to low-level target reffectivities, adding ballistic rejection of scatter and clutter in the range coordinate, and introducing multispectral and polarization discrimination capability in a wavelen~h-tunable, high gain nonlinear optical component with strong potential for source miniaturization. A key advantage of integrating amplification and tlequency up-conversion functions within a phasematched three-wave mixing parametric device is the ability to petiorm background-free imaging with eye-safe or longer inilared illumination wavelengths (idler) less susceptible to scatter without sacrificing quantum efficiency in the detection process at the corresponding signal wavelength. We report benchmark laboratory experiments in which the OPA gating process has been successfidly demonstrated in both transillumination and reflection test geometries with extended pathlengths representative of realistic coastal sea water and cumulus cloud

  12. GEMINI/GeMS Observations Unveil the Structure of the Heavily Obscured Globular Cluster Liller 1.

    NASA Astrophysics Data System (ADS)

    Saracino, S.; Dalessandro, E.; Ferraro, F. R.; Lanzoni, B.; Geisler, D.; Mauro, F.; Villanova, S.; Moni Bidin, C.; Miocchi, P.; Massari, D.

    2015-06-01

    By exploiting the exceptional high-resolution capabilities of the near-IR camera GSAOI combined with the Gemini Multi-Conjugate Adaptive System at the GEMINI South Telescope, we investigated the structural and physical properties of the heavily obscured globular cluster Liller 1 in the Galactic bulge. We have obtained the deepest and most accurate color-magnitude diagram published so far for this cluster, reaching {{K}s}˜ 19 (below the main-sequence turnoff level). We used these data to redetermine the center of gravity of the system, finding that it is located about 2.″2 southeast from the literature value. We also built new star density and surface brightness profiles for the cluster and rederived its main structural and physical parameters (scale radii, concentration parameter, central mass density, total mass). We find that Liller 1 is significantly less concentrated (concentration parameter c=1.74) and less extended (tidal radius {{r}t}=298\\prime\\prime and core radius {{r}c}=5\\buildrel{\\prime\\prime}\\over{.} 39) than previously thought. By using these newly determined structural parameters, we estimated the mass of Liller 1 to be {{M}tot}=2.3+0.3-0.1× {{10}6} {{M}⊙ } ({{M}tot}=1.5+0.2-0.1× {{10}6} {{M}⊙ } for a Kroupa initial mass function), which is comparable to that of the most massive clusters in the Galaxy (ω Centari and Terzan 5). Also, Liller 1 has the second-highest collision rate (after Terzan 5) among all star clusters in the Galaxy, thus confirming that it is an ideal environment for the formation of collisional objects (such as millisecond pulsars). Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da

  13. Herschel spectroscopic observations of the compact obscured nucleus in Zw 049.057

    NASA Astrophysics Data System (ADS)

    Falstad, N.; González-Alfonso, E.; Aalto, S.; van der Werf, P. P.; Fischer, J.; Veilleux, S.; Meléndez, M.; Farrah, D.; Smith, H. A.

    2015-08-01

    Context. The luminous infrared galaxy Zw 049.057 contains a compact obscured nucleus where a considerable amount of the galaxy's luminosity is generated. This nucleus contains a dusty environment that is rich in molecular gas. One approach to probing this kind of environment and to revealing what is hidden behind the dust is to study the rotational lines of molecules that couple well with the infrared radiation emitted by the dust. Aims: We probe the physical conditions in the core of Zw 049.057 and establish the nature of its nuclear power source (starburst or active galactic nucleus). Methods: We observed Zw 049.057 with the Photodetector Array Camera and Spectrometer (PACS) and the Spectral and Photometric Imaging Receiver (SPIRE) onboard the Herschel Space Observatory in rotational lines of H2O, H218O, OH, 18OH, and [O I]. We modeled the unresolved core of the galaxy using a spherically symmetric radiative transfer code. To account for the different excitation requirements of the various molecular transitions, we use multiple components and different physical conditions. Results: We present the full high-resolution SPIRE FTS spectrum of Zw 049.057, along with relevant spectral scans in the PACS range. We find that a minimum of two different components (nuclear and extended) are required in order to account for the rich molecular line spectrum of Zw 049.057. The nuclear component has a radius of 10-30 pc, a very high infrared surface brightness (~1014L⊙kpc-2), warm dust (Td > 100 K), and a very large H2 column density (NH2 = 1024-1025 cm-2). The modeling also indicates high nuclear H2O (~5 × 10-6) and OH (~4 × 10-6) abundances relative to H2 as well as a low 16O/18O-ratio of 50-100. We also find a prominent infall signature in the [O I] line. We tentatively detect a 500 km s-1 outflow in the H2O 313 → 202 line. Conclusions: The high surface brightness of the core indicates the presence of either a buried active galactic nucleus or a very dense nuclear

  14. X-ray observations of dust obscured galaxies in the Chandra deep field south

    NASA Astrophysics Data System (ADS)

    Corral, A.; Georgantopoulos, I.; Comastri, A.; Ranalli, P.; Akylas, A.; Salvato, M.; Lanzuisi, G.; Vignali, C.; Koutoulidis, L.

    2016-08-01

    We present the properties of X-ray detected dust obscured galaxies (DOGs) in the Chandra deep field south. In recent years, it has been proposed that a significant percentage of the elusive Compton-thick (CT) active galactic nuclei (AGN) could be hidden among DOGs. This type of galaxy is characterized by a very high infrared (IR) to optical flux ratio (f24 μm/fR > 1000), which in the case of CT AGN could be due to the suppression of AGN emission by absorption and its subsequent re-emission in the IR. The most reliable way of confirming the CT nature of an AGN is by X-ray spectroscopy. In a previous work, we presented the properties of X-ray detected DOGs by making use of the deepest X-ray observations available at that time, the 2Ms observations of the Chandra deep fields, the Chandra deep field north (CDF-N), and the Chandra deep field south (CDF-S). In that work, we only found a moderate percentage (<50%) of CT AGN among the DOGs sample. However, we pointed out that the limited photon statistics for most of the sources in the sample did not allow us to strongly constrain this number. In this paper, we further explore the properties of the sample of DOGs in the CDF-S presented in that work by using not only a deeper 6Ms Chandra survey of the CDF-S, but also by combining these data with the 3Ms XMM-Newton survey of the CDF-S. We also take advantage of the great coverage of the CDF-S region from the UV to the far-IR to fit the spectral energy distributions (SEDs) of our sources. Out of the 14 AGN composing our sample, 9 are highly absorbed (NH > 1023 cm-2), whereas 2 look unabsorbed, and the other 3 are only moderately absorbed. Among the highly absorbed AGN, we find that only three could be considered CT AGN. In only one of these three cases, we detect a strong Fe Kα emission line; the source is already classified as a CT AGN with Chandra data in a previous work. Here we confirm its CT nature by combining Chandra and XMM-Newton data. For the other two CT

  15. A spectroscopic survey of WISE-selected obscured quasars with the southern african large telescope

    SciTech Connect

    Hainline, Kevin N.; Hickox, Ryan C.; Carroll, Christopher M.; Myers, Adam D.; DiPompeo, Michael A.; Trouille, Laura

    2014-11-10

    We present the results of an optical spectroscopic survey of a sample of 40 candidate obscured quasars identified on the basis of their mid-infrared emission detected by the Wide-Field Infrared Survey Explorer (WISE). Optical spectra for this survey were obtained using the Robert Stobie Spectrograph on the Southern African Large Telescope. Our sample was selected with WISE colors characteristic of active galactic nuclei (AGNs), as well as red optical to mid-IR colors indicating that the optical/UV AGN continuum is obscured by dust. We obtain secure redshifts for the majority of the objects that comprise our sample (35/40), and find that sources that are bright in the WISE W4 (22 μm) band are typically at moderate redshift ((z) = 0.35) while sources fainter in W4 are at higher redshifts ((z) = 0.73). The majority of the sources have narrow emission lines with optical colors and emission line ratios of our WISE-selected sources that are consistent with the locus of AGN on the rest-frame g – z color versus [Ne III] λ3869/[O II] λλ3726+3729 line ratio diagnostic diagram. We also use empirical AGN and galaxy templates to model the spectral energy distributions (SEDs) for the objects in our sample, and find that while there is significant variation in the observed SEDs for these objects, the majority require a strong AGN component. Finally, we use the results from our analysis of the optical spectra and the SEDs to compare our selection criteria to alternate criteria presented in the literature. These results verify the efficacy of selecting luminous obscured AGNs based on their WISE colors.

  16. Unveiling the Composite Nature of Dust-Obscured Galaxies (DOGs) with Herschel

    NASA Astrophysics Data System (ADS)

    Riguccini, Laurie A.; Le Floc'h, Emeric; Mullaney, James

    2015-08-01

    DOGs are bright 24um-selected sources with extreme obscuration at optical wavelengths. Some of them are characterized by a rising power-law continuum of hot dust (T_D ~ 200-1000 K) in the near-IR emission indicating that their mid-IR luminosity is dominated by an AGN. Whereas DOGs with a fainter 24um flux display a stellar bump and their mid-IR luminosity is believed to be mainly powered by dusty star-formation. Another explanation is that the mid-IR emission still comes from AGN activity but the torus emission is so obscured that it becomes negligible with respect to the emission from the host component.In an effort to characterize the nature of the physical processes underlying their IR emission, we focus on DOGs (F24/FR>982) within the COSMOS field with Herschel data and derive their far-IR properties (e.g., total IR luminosities; mid-to-far IR colors; dust temperatures and masses and AGN contribution) based on SED fitting.Of particular interest are the 24um-bright DOGs (F24>1mJy). They present bluer far-IR/mid-IR colors than the rest of the sample, unveiling the potential presence of an AGN. The AGN contribution to the total 8-1000um flux increases as a function of the rest-frame 8um-luminosity irrespective of the redshift, with a stronger contribution at lower redshift. This confirms that faint DOGs (F24<1mJy) are dominated by star-formation while brighter DOGs show a larger contribution from an AGN.Is this FIR-selection technique allowing us to probe a new population of obscured AGN? Or does it corresponds to already known AGN in the X-rays, NIR or radio? The wealth of multi wavelength data in COSMOS will allow us to describe our results here.

  17. Using VO tools to investigate distant radio starbursts hosting obscured AGN in the HDF(N) region

    NASA Astrophysics Data System (ADS)

    Richards, A. M. S.; Muxlow, T. W. B.; Beswick, R.; Allen, M. G.; Benson, K.; Dickson, R. C.; Garrett, M. A.; Garrington, S. T.; Gonzalez-Solarez, E.; Harrison, P. A.; Holloway, A. J.; Kettenis, M. M.; Laing, R. A.; Richards, E. A.; Thrall, H.; van Langevelde, H. J.; Walton, N. A.; Wilkinson, P. N.; Winstanley, N.

    2007-09-01

    Context: A 10-arcmin region around the Hubble Deep Field (North) contains 92 radio sources brighter than 40 μJy which are well-resolved by MERLIN+VLA at 0.2arcsec-2' resolution (average size ~1"). 55 of these have Chandra X-ray counterparts in the 2-Ms CDF(N) field including at least 17 with a hard X-ray photon index and high luminosity characteristic of a type-II (obscured) AGN. More than 70% of the radio sources have been classified as starbursts or AGN using radio morphologies, spectral indices and comparisons with optical appearance and rest-frame MIR emission. On this basis, starbursts outnumber radio AGN 3:1. Aims: We investigate the possibility that very luminous radio and X-ray emission originates from different phenomena in the same high-redshift galaxies. Methods: This study extends the Virtual Observatory (VO) methods previously used to identify X-ray-selected obscured type-II AGN, to examine the relationship between radio and X-ray emission. We describe a VO cut-out server for MERLIN+VLA 1.4-GHz radio images in the HDF(N) region. Results: The high-redshift starbursts have typical sizes of 5-10 kpc and star formation rates of ~1000 M⊙ yr-1, an order of magnitude more extended and intense than in the local universe. There is no obvious correlation between radio and X-ray luminosities nor spectral indices at z ⪆ 1.3. About 70% of both the radio-selected AGN and the starburst samples were detected by Chandra. The X-ray luminosity indicates the presence of an AGN in at least half of the 45 cross-matched radio starbursts. Eleven of these are type-II AGN, of which 7 are at z ≥ 1.5. This distribution overlaps closely with the X-ray detected radio sources which were also detected by SCUBA. In contrast, all but one of the AGN-dominated radio sources are at z < 1.5, including the 4 which are also X-ray selected type-II AGN. The stacked 1.4-GHz emission at the positions of radio-faint X-ray sources is correlated with X-ray hardness. Conclusions: Almost all

  18. Herschel reveals the obscured star formation in HiZELS Hα emitters at z = 1.47

    NASA Astrophysics Data System (ADS)

    Ibar, E.; Sobral, D.; Best, P. N.; Ivison, R. J.; Smail, I.; Arumugam, V.; Berta, S.; Béthermin, M.; Bock, J.; Cava, A.; Conley, A.; Farrah, D.; Geach, J.; Ikarashi, S.; Kohno, K.; Le Floc'h, E.; Lutz, D.; Magdis, G.; Magnelli, B.; Marsden, G.; Oliver, S. J.; Page, M. J.; Pozzi, F.; Riguccini, L.; Schulz, B.; Seymour, N.; Smith, A. J.; Symeonidis, M.; Wang, L.; Wardlow, J.; Zemcov, M.

    2013-10-01

    obscured star-forming regions, especially in massive galaxies where these dominate. The luminosity-limited HiZELS sample tends to lie above of the so-called main sequence for star-forming galaxies, especially at low stellar masses, indicating high star formation efficiencies in these galaxies. This work has implications for SFR indicators and suggests that obscured star formation is linked to the assembly of stellar mass, with deeper potential wells in massive galaxies providing dense, heavily obscured environments in which stars can form rapidly.

  19. [Non-small bowel lesions detected with capsule endoscopy in patients with obscure gastrointestinal bleeding].

    PubMed

    Juanmartiñena Fernández, J F; Fernández-Urién, I; Saldaña Dueñas, C; Elosua González, A; Borda Martín, A; Vila Costas, J J

    Obscure gastrointestinal bleeding accounts for approximately 5-10% of patients presenting with gastrointestinal haemorrhage. The majority of lesions responsible were found to be located in the small bowel. Currently, capsule en-doscopy is the first-line tool to investigate the small bowel as it is a non-invasive, feasible and simple procedure. Howe-ver, capsule endoscopy sometimes identifies the source of bleeding outside the small bowel and within the reach of conventional endoscopy. We present the case of a 46 year-old man with few prior negative endoscopic procedures and iron-deficiency anaemia due to gastric GIST. PMID:27599960

  20. Unmasking a shady mirror effect: recognition of normal versus obscured faces.

    PubMed

    Vokey, John R; Hockley, William E

    2012-01-01

    Hockley, Hemsworth, and Consoli (1999) found that following the study of normal faces, a recognition test of normal faces versus faces wearing sunglasses produced a mirror effect: The sunglasses manipulation decreased hit rates and increased false-alarm rates. The stimuli used by Hockley et al. (1999) consisted of separate poses of models wearing or not wearing sunglasses. In the current experiments, we separately manipulated same versus different depictions of individual faces and whether or not the faces were partially obscured. The results of a simulation and four experiments suggest that the test-based, mirror effect observed by Hockley et al. (1999) is actually two separable effects.

  1. Proliferation pattern during rostrum regeneration of the symbiotic flatworm Paracatenula galateia: a pulse-chase-pulse analysis.

    PubMed

    Dirks, Ulrich; Gruber-Vodicka, Harald R; Egger, Bernhard; Ott, Jörg A

    2012-08-01

    The remarkable totipotent stem-cell-based regeneration capacities of the Platyhelminthes have brought them into the focus of stem cell and regeneration research. Although selected platyhelminth groups are among the best-studied invertebrates, our data provide new insights into regenerative processes in the most basally branching group of the Platyhelminthes, the Catenulida. The mouth- and gutless free-living catenulid flatworm Paracatenula galateia harbors intracellular bacterial symbionts in its posterior body region, the trophosome region, accounting for up to 50% of the volume. Following decapitation of this flatworm, we have analyzed the behavior of the amputated fragments and any anterior and posterior regeneration. Using an EdU-pulse-chase/BrdU-pulse thymidine analog double-labeling approach combined with immunohistochemistry, we show that neoblasts are the main drivers of the regeneration processes. During anterior (rostrum) regeneration, EdU-pulse-chase-labeled cells aggregate inside the regenerating rostrum, whereas BrdU pulse-labeling before fixation indicates clusters of S-phase neoblasts at the same position. In parallel, serotonergic nerves reorganize and the brain regenerates. In completely regenerated animals, the original condition with S-phase neoblasts being restricted to the body region posterior to the brain is restored. In contrast, no posterior regeneration or growth of the trophosome region in anterior fragments cut a short distance posterior to the brain has been observed. Our data thus reveal interesting aspects of the cellular processes underlying the regeneration of the emerging catenulid-bacteria symbiosis model P. galateia and show that a neoblast stem cell system is indeed a plesiomorphic feature of basal platyhelminths.

  2. The Physicochemical Stability of Complex Intravenous Lipid Dispersions Supported by Light Obscuration and Dynamic Light Scattering Techniques.

    NASA Astrophysics Data System (ADS)

    Driscoll, David Francis

    1994-01-01

    Procedures. The physicochemical stability of 45 clinically relevant intravenous nutritional emulsions were assessed employing a balanced fractional factorial design. Six factors were identified as influencing stability and included final concentrations of (1) Amino acids (%); (2) Glucose (%); (3) Lipids (%); (4) Monovalent Cations (mEq/L); (5) Divalent Cations (mEq/L); (6) Trivalent Cations (mg/L) Stability assessments included particle size analysis, pH changes and the visual development of cream layers and phase separation of free oil. Particle size analyses were accomplished employing laser techniques for particle counting and distribution. Particle sizing and counting was achieved using light obscuration and particle distributions were constructed with the aid of dynamic light scatter techniques. Results. Multiple stepwise regression analyses revealed that trivalent cation concentrations (as iron dextran) was the only variable to have any significant effect on the emulsions accounting for almost 60% of the adverse changes in the emulsions (increasing lipid particle sizes) during the course of the investigation. In addition, when the percent fat (PFAT) from time 0 comprised > 0.4% in the size range of >5 μm in diameter, it was associated with, highly unstable and potentially dangerous infusions. Importantly, these unstable emulsions were visually detectable only about 65% of the time. Assessment of the potential danger of these formulations with respect to pulmonary embolism was performed by infusing the admixture with the worst emulsion profile, yet was visually acceptable, in two groups of guinea pigs. Group 1 received the admixture which contained iron dextran and Group 2 received the identical admixture without iron dextran. The admixtures were prepared 24 hours prior to infusion and given to the animals over the last six hours of its expiration date. Prior to infusion, particle size analysis revealed a 100-fold increase in PFAT >5 μm in the iron dextran

  3. CONTRIBUTION OF THE ACCRETION DISK, HOT CORONA, AND OBSCURING TORUS TO THE LUMINOSITY OF SEYFERT GALAXIES: INTEGRAL AND SPITZER OBSERVATIONS

    SciTech Connect

    Sazonov, S.; Churazov, E.; Krivonos, R.; Revnivtsev, M.; Sunyaev, R.; Vikhlinin, A.; Hickox, R. C.; Gorjian, V.; Werner, M. W.; Fabian, A. C.; Forman, W. R.

    2012-10-01

    We estimate the relative contributions of the supermassive black hole (SMBH) accretion disk, corona, and obscuring torus to the bolometric luminosity of Seyfert galaxies, using Spitzer mid-infrared (MIR) observations of a complete sample of 68 nearby active galactic nuclei (AGNs) from the INTEGRAL all-sky hard X-ray (HX) survey. This is the first HX-selected (above 15 keV) sample of AGNs with complementary high angular resolution, high signal-to-noise, MIR data. Correcting for the host galaxy contribution, we find a correlation between HX and MIR luminosities: L{sub 15{mu}m}{proportional_to}L{sup 0.74{+-}0.06}{sub HX}. Assuming that the observed MIR emission is radiation from an accretion disk reprocessed in a surrounding dusty torus that subtends a solid angle decreasing with increasing luminosity (as inferred from the declining fraction of obscured AGNs), the intrinsic disk luminosity, L{sub Disk}, is approximately proportional to the luminosity of the corona in the 2-300 keV energy band, L{sub Corona}, with the L{sub Disk}/L{sub Corona} ratio varying by a factor of 2.1 around a mean value of 1.6. This ratio is a factor of {approx}2 smaller than for typical quasars producing the cosmic X-ray background. Therefore, over three orders of magnitude in luminosity, HX radiation carries a large, and roughly comparable, fraction of the bolometric output of AGNs. We estimate the cumulative bolometric luminosity density of local AGNs at {approx}(1-3) Multiplication-Sign 10{sup 40} erg s{sup -1} Mpc{sup -3}. Finally, the Compton temperature ranges between kT{sub c} Almost-Equal-To 2 and Almost-Equal-To 6 keV for nearby AGNs, compared to kT{sub c} Almost-Equal-To 2 keV for typical quasars, confirming that radiative heating of interstellar gas can play an important role in regulating SMBH growth.

  4. The formation of aromatic molecules in heavily obscured post-AGB stars with O-rich masers

    NASA Astrophysics Data System (ADS)

    Garcia-Lario, Pedro; Garcia-Hernandez, Domingo Aníbal; Cernicharo, Jose; Perea-Calderon, Jose Vicente; Engels, Dieter

    2015-08-01

    We report Spitzer/IRS spectra of a small sample of heavily obscured and high mass loss post-AGB stars with O-rich maser emission. IRAM 30 m observations for two post-AGBs are also reported. The Spitzer/IRS spectra show the C-rich character of their circumstellar envelopes (CSE), as revealed by the presence of small hydrocarbon molecules such as C2H2, C4H2, C6H2, C6H6 , and HCN. Benzene (C6H6) is detected toward two sources in our sample, bringing up to three the total number of Galactic post-AGB objects where this molecule has been detected. The available IRAM 30 m data confirm that the central stars are C-rich, despite the presence of O-rich masers, and the presence of high velocity molecular outflows together with extreme mass loss rates (10-4 M⊙ yr-1). Our Spitzer and IRAM 30 m observations confirm the model of Cernicharo (2004) that predicts a rich photochemistry in the neutral regions of these objects on timescales shorter than the dynamical evolution of the central HII region, leading to the formation of large, complex carbon-rich molecules. This model also explain the presence of O-rich masers in C-rich post-AGB stars as a consequence of the extreme mass loss rate, being not necessary to invoke a chemistry change in their circumstellar envelopes.

  5. See-through obscurants via compressive sensing in degraded visual environment

    NASA Astrophysics Data System (ADS)

    Lau, Richard C.; Woodward, T. K.

    2015-05-01

    This paper proposes a new approach for seeing through obscurants in a severe degraded visual environment (DVE). The proposed method allows extraction of hidden information from the raw sensor data via computational imaging technologies. We show that although to the human eye a sensor captures a zero-visibility view of an object through dense obscurants, it is possible to recover the hidden visual information of the object and display its visual cue to the aircraft pilot to aid in landing and maneuvering. The proposed approach uses a compressive sensing algorithm incorporating an over-complete dictionary composed of pose transformation of the targeted object. Information on the recovered image is used in a feedback loop to further remove perception noise and maintain tracking of the object from a moving aircraft. The proposed algorithm is sensor agnostic and can be applied to images taken from Infrared, LIDAR, or RF imagery sensors. We quantify the upper bound of the DVE noise in which the proposed method is effective via simulation results.

  6. The obscuration by dust of most of the growth of supermassive black holes.

    PubMed

    Martínez-Sansigre, Alejo; Rawlings, Steve; Lacy, Mark; Fadda, Dario; Marleau, Francine R; Simpson, Chris; Willott, Chris J; Jarvis, Matt J

    2005-08-01

    Supermassive black holes underwent periods of exponential growth during which we see them as quasars in the distant Universe. The summed emission from these quasars generates the cosmic X-ray background, the spectrum of which has been used to argue that most black-hole growth is obscured. There are clear examples of obscured black-hole growth in the form of 'type-2' quasars, but their numbers are fewer than expected from modelling of the X-ray background. Here we report the direct detection of a population of distant type-2 quasars, which is at least comparable in size to the well-known unobscured type-1 population. We selected objects that have mid-infrared and radio emissions characteristic of quasars, but which are faint at near-infrared and optical wavelengths. We conclude that this population is responsible for most of the black-hole growth in the young Universe and that, throughout cosmic history, black-hole growth occurs in the dusty, gas-rich centres of active galaxies.

  7. Delving into X-ray obscuration of type 2 AGN, near and far

    SciTech Connect

    LaMassa, Stephanie M.; Meg Urry, C.; Yaqoob, Tahir; Ptak, Andrew F.; Gandhi, Poshak

    2014-05-20

    Using self-consistent, physically motivated models, we investigate the X-ray obscuration in 19 Type 2 [O III] 5007 Å selected active galactic nuclei (AGNs), 9 of which are local Seyfert 2 galaxies and 10 of which are Type 2 quasar candidates. We derive reliable line-of-sight and global column densities for these objects, which is the first time this has been reported for an AGN sample; four AGNs have significantly different global and line-of-sight column densities. Five sources are heavily obscured to Compton-thick. We comment on interesting sources revealed by our spectral modeling, including a candidate 'naked' Sy2. After correcting for absorption, we find that the ratio of the rest-frame, 2-10 keV luminosity (L{sub 2-10} {sub keV,} {sub in}) to L{sub [O} {sub III]} is 1.54 ± 0.49 dex which is essentially identical to the mean Type 1 AGN value. The Fe Kα luminosity is significantly correlated with L{sub [O} {sub III]} but with substantial scatter. Finally, we do not find a trend between L {sub 2-10keV,} {sub in} and global or line-of-sight column density, between column density and redshift, between column density and scattering fraction, or between scattering fraction and redshift.

  8. Delving Into X-ray Obscuration of Type 2 AGN, Near and Far

    NASA Astrophysics Data System (ADS)

    LaMassa, Stephanie M.; Yaqoob, Tahir; Ptak, Andrew F.; Jia, Jianjun; Heckman, Timothy M.; Gandhi, Poshak; Meg Urry, C.

    2014-05-01

    Using self-consistent, physically motivated models, we investigate the X-ray obscuration in 19 Type 2 [O III] 5007 Å selected active galactic nuclei (AGNs), 9 of which are local Seyfert 2 galaxies and 10 of which are Type 2 quasar candidates. We derive reliable line-of-sight and global column densities for these objects, which is the first time this has been reported for an AGN sample; four AGNs have significantly different global and line-of-sight column densities. Five sources are heavily obscured to Compton-thick. We comment on interesting sources revealed by our spectral modeling, including a candidate "naked" Sy2. After correcting for absorption, we find that the ratio of the rest-frame, 2-10 keV luminosity (L 2-10 keV, in) to L [O III] is 1.54 ± 0.49 dex which is essentially identical to the mean Type 1 AGN value. The Fe Kα luminosity is significantly correlated with L [O III] but with substantial scatter. Finally, we do not find a trend between L 2-10 keV, in and global or line-of-sight column density, between column density and redshift, between column density and scattering fraction, or between scattering fraction and redshift.

  9. AGN obscuration from winds: from dusty infrared-driven to warm and X-ray photoionized

    PubMed Central

    Dorodnitsyn, A.; Kallman, T.

    2016-01-01

    We present calculations of AGN winds at ~parsec scales, along with the associated obscuration. We take into account the pressure of infrared radiation on dust grains and the interaction of X-rays from a central black hole with hot and cold plasma. Infrared radiation (IR) is incorporated in radiation-hydrodynamic simulations adopting the flux-limited diffusion approximation. We find that in the range of X-ray luminosities L=0.05 – 0.6Ledd, the Compton-thick part of the flow (aka torus) has an opening angle of approximately 72° – 75° regardless of the luminosity. At L ≳ 0.1 the outflowing dusty wind provides the obscuration with IR pressure playing a major role. The global flow consists of two phases: the cold flow at inclinations θ ≳ 70° and a hot, ionized wind of lower density at lower inclinations. The dynamical pressure of the hot wind is important in shaping the denser IR supported flow. At luminosities ≤0.1Ledd episodes of outflow are followed by extended periods when the wind switches to slow accretion.

  10. Delving into X-Ray Obscuration of Type 2 AGN, Near and Far

    NASA Technical Reports Server (NTRS)

    Lamassa, Stephanie M.; Yaqoob, Tahir; Ptak, Andrew F.; Jia, Jianjun; Heckman, Timothy M.; Gandhi, Poshak; Urry, C. Meg

    2014-01-01

    Using self-consistent, physically motivated models, we investigate the X-ray obscuration in 19 Type 2 [O iii] 5007Å selected active galactic nuclei (AGNs), 9 of which are local Seyfert 2 galaxies and 10 of which are Type 2 quasar candidates. We derive reliable line-of-sight and global column densities for these objects, which is the first time this has been reported for an AGN sample; four AGNs have significantly different global and line-of-sight column densities. Five sources are heavily obscured to Compton-thick. We comment on interesting sources revealed by our spectral modeling, including a candidate "naked" Sy2. After correcting for absorption, we find that the ratio of the rest-frame, 2-10 keV luminosity (L2-10 keV,in) to L[O iii] is 1.54 +/- 0.49 dex which is essentially identical to the mean Type 1 AGN value. The Fe K(alpha) luminosity is significantly correlated with L[O iii] but with substantial scatter. Finally, we do not find a trend between L2-10 keV,in and global or line-of-sight column density, between column density and redshift, between column density and scattering fraction, or between scattering fraction and redshift. Key words: galaxies: active - galaxies: Seyfert - X-rays: general

  11. AGN Obscuration from Winds: From Dusty Infrared-Driven to Warm and X-Ray Photoionized

    NASA Technical Reports Server (NTRS)

    Dorodnitsyn, A.; Kallman, T.

    2012-01-01

    We present calculations of AGN winds at approximate parsec scales, along with the associated obscuration. We take into account the pressure of infrared radiation on dust grains and the interaction of X-rays from a central black hole with hot and cold plasma. Infrared radiation (IR) is incorporated in radiation-hydrodynamic simulations adopting the flux-limited diffusion approximation. We find that in the range of X-ray luminosities L=0.05 - 0.6L(sub Edd) the Compton-thick part of the flow (aka torus) has an opening angle of approximately 72? -75? regardless of the luminosity. At L 0.1 the outflowing dusty wind provides the obscuration with IR pressure playing a major role. The global flow consists of two phases: the cold flow at inclinations (theta) greater than or approximately 70? and a hot, ionized wind of lower density at lower inclinations. The dynamical pressure of the hot wind is important in shaping the denser IR supported flow. At luminosities less than or equal to 0.1L(sub Edd) episodes of outflow are followed by extended periods when the wind switches to slow accretion.

  12. Deep Mid-Infrared Silicate Absorption as a Diagnostic of Obscuring Geometry toward Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Levenson, N. A.; Sirocky, M. M.; Hao, L.; Spoon, H. W. W.; Marshall, J. A.; Elitzur, M.; Houck, J. R.

    2007-01-01

    The silicate cross section peak near 10 μm produces emission and absorption features in the spectra of dusty galactic nuclei observed with the Spitzer Space Telescope. Especially in ultraluminous infrared galaxies, the observed absorption feature can be extremely deep, as IRAS 08572+3915 illustrates. A foreground screen of obscuration cannot reproduce this observed feature, even at a large optical depth. Instead, the deep absorption requires a nuclear source to be deeply embedded in a smooth distribution of material that is both geometrically and optically thick. In contrast, a clumpy medium can produce only shallow absorption or emission, which are characteristic of optically identified active galactic nuclei. In general, the geometry of the dusty region and the total optical depth, rather than the grain composition or heating spectrum, determine the silicate feature's observable properties. The apparent optical depth calculated from the ratio of line to continuum emission generally fails to accurately measure the true optical depth. The obscuring geometry, not the nature of the embedded source, also determines the far-IR spectral shape.

  13. Pyloric giant Brunner's gland hamartoma as a cause of both duodenojejunal intussusception and obscure gastrointestinal bleeding.

    PubMed

    Bayan, Kadim; Tüzün, Yekta; Yilmaz, Serif; Yilmaz, Gülşen; Bilici, Aslan

    2009-03-01

    Obscure gastrointestinal bleeding is an important dilemma. Brunner's gland hamartoma is an extremely rare tumor generally localized in the duodenal bulb. We present a 34-year-old woman who had suffered from several episodes of melena for the past three years. Endoscopic examinations were normal. Computed tomography showed a large target lesion over the right abdomen and an image representing intestinal malrotation, which was supported by enteroclysis. At exploratory laparotomy, ligamentum of Treitz was located in the mid-to-right side of the columna vertebralis, and the duodenal bulb was found to be invaginated into the proximal jejunum. After longitudinal duodenotomy, a pedunculated ring-shaped large polyp originating from the pyloric ring was seen and excised. Histology was consistent with Brunner's gland hamartoma. This case with obscure bleeding was original with respect to its rarity and being a huge, ring-shaped tumor with pyloric localization. Moreover, the patient had a rare clinical presentation of duodenojejunal intussusception with accompanying intestinal malrotation.

  14. Using R-W1 to Uncover Obscured AGN in X-ray Surveys

    NASA Astrophysics Data System (ADS)

    Lamassa, Stephanie

    2016-08-01

    X-ray surveys provide perhaps the most efficient method for discovering AGN across the Universe, though a major challenge is the time investment involved in following-up X-ray sources to identify them. To make the best use of limited resources, we explored the efficacy of m_r (optical) - m_3.4-micron (mid-infrared), hereafter R-W1, as a color diagnostic to hone in on signatures of obscured black hole growth in wide-area X-ray surveys which would otherwise be missed in optical and infrared surveys. We calibrated this color on the 16.5 deg^2 release of the Stripe 82X survey, finding that most X-ray emitting stars lie along a well-defined locus in R-W1 v. R-K color space and most AGN hosted in optically normal galaxies beyond z>0.5 have red R-W1 colors (R-W1 > 4 Vega). Our results will be useful for crafting target lists for current and future wide-area X-ray surveys to follow-up the most promising obscured AGN candidates.

  15. The angular clustering of WISE-selected active galactic nuclei: Different halos for obscured and unobscured active galactic nuclei

    SciTech Connect

    Donoso, E.; Yan, Lin; Stern, D.; Assef, R. J.

    2014-07-01

    We calculate the angular correlation function for a sample of ∼170,000 active galactic nuclei (AGNs) extracted from the Wide-field Infrared Survey Explorer (WISE) catalog, selected to have red mid-IR colors (W1 – W2 > 0.8) and 4.6 μm flux densities brighter than 0.14 mJy). The sample is expected to be >90% reliable at identifying AGNs and to have a mean redshift of (z) = 1.1. In total, the angular clustering of WISE AGNs is roughly similar to that of optical AGNs. We cross-match these objects with the photometric Sloan Digital Sky Survey catalog and distinguish obscured sources with r – W2 > 6 from bluer, unobscured AGNs. Obscured sources present a higher clustering signal than unobscured sources. Since the host galaxy morphologies of obscured AGNs are not typical red sequence elliptical galaxies and show disks in many cases, it is unlikely that the increased clustering strength of the obscured population is driven by a host galaxy segregation bias. By using relatively complete redshift distributions from the COSMOS survey, we find that obscured sources at (z) ∼ 0.9 have a bias of b = 2.9 ± 0.6 and are hosted in dark matter halos with a typical mass of log (M/M {sub ☉} h {sup –1}) ∼ 13.5. In contrast, unobscured AGNs at (z) ∼ 1.1 have a bias of b = 1.6 ± 0.6 and inhabit halos of log (M/M {sub ☉} h {sup –1}) ∼ 12.4. These findings suggest that obscured AGNs inhabit denser environments than unobscured AGNs, and they are difficult to reconcile with the simplest AGN unification models, where obscuration is driven solely by orientation.

  16. THE STAR FORMATION HISTORIES OF z {approx} 2 DUST-OBSCURED GALAXIES AND SUBMILLIMETER-SELECTED GALAXIES

    SciTech Connect

    Bussmann, R. S.; Dey, Arjun; Jannuzi, B. T.; Armus, L.; Desai, V.; Soifer, B. T.; Brown, M. J. I.; Gonzalez, A. H.; Melbourne, J.

    2012-01-10

    The Spitzer Space Telescope has identified a population of ultraluminous infrared galaxies (ULIRGs) at z {approx} 2 that may play an important role in the evolution of massive galaxies. We measure the stellar masses (M{sub *}) of two populations of Spitzer-selected ULIRGs that have extremely red R - [24] colors (dust-obscured galaxies, or DOGs) and compare our results with submillimeter-selected galaxies (SMGs). One set of 39 DOGs has a local maximum in their mid-infrared (mid-IR) spectral energy distribution (SED) at rest frame 1.6 {mu}m associated with stellar emission ({sup b}ump DOGs{sup )}, while the other set of 51 DOGs have power-law mid-IR SEDs that are typical of obscured active galactic nuclei ({sup p}ower-law DOGs{sup )}. We measure M{sub *} by applying Charlot and Bruzual stellar population synthesis models to broadband photometry in the rest-frame ultraviolet, optical, and near-infrared of each of these populations. Assuming a simple stellar population and a Chabrier initial mass function, we find that power-law DOGs and bump DOGs are on average a factor of 2 and 1.5 more massive than SMGs, respectively (median and inter-quartile M{sub *} values for SMGs, bump DOGs, and power-law DOGs are log(M{sub *}/M{sub Sun }) = 10.42{sup +0.42}{sub -0.36}, 10.62{sup +0.36}{sub -0.32}, and 10.71{sup +0.40}{sub -0.34}, respectively). More realistic star formation histories drawn from two competing theories for the nature of ULIRGs at z {approx} 2 (major merger versus smooth accretion) can increase these mass estimates by up to 0.5 dex. A comparison of our stellar masses with the instantaneous star formation rate (SFR) in these z {approx} 2 ULIRGs provides a preliminary indication supporting high SFRs for a given M{sub *}, a situation that arises more naturally in major mergers than in smooth accretion-powered systems.

  17. The Geometry of the Infrared and X-Ray Obscurer in a Dusty Hyperluminous Quasar

    NASA Astrophysics Data System (ADS)

    Farrah, Duncan; Baloković, Mislav; Stern, Daniel; Harris, Kathryn; Kunimoto, Michelle; Walton, Dominic J.; Alexander, David M.; Arévalo, Patricia; Ballantyne, David R.; Bauer, Franz E.; Boggs, Steven; Brandt, William N.; Brightman, Murray; Christensen, Finn; Clements, David L.; Craig, William; Fabian, Andrew; Hailey, Charles; Harrison, Fiona; Koss, Michael; Lansbury, George B.; Luo, Bin; Paine, Jennie; Petty, Sara; Pitchford, Kate; Ricci, Claudio; Zhang, William

    2016-11-01

    We study the geometry of the active galactic nucleus (AGN) obscurer in IRAS 09104+4109, an IR-luminous, radio-intermediate FR-I source at z = 0.442, using infrared data from Spitzer and Herschel, X-ray data from NuSTAR, Swift, Suzaku, and Chandra, and an optical spectrum from Palomar. The infrared data imply a total rest-frame 1–1000 μm luminosity of 5.5 × 1046 erg s‑1 and require both an AGN torus and a starburst model. The AGN torus has an anisotropy-corrected IR luminosity of 4.9 × 1046 erg s‑1 and a viewing angle and half-opening angle both of approximately 36° from pole-on. The starburst has a star formation rate of (110 ± 34) M ⊙ yr‑1 and an age of <50 Myr. These results are consistent with two epochs of luminous activity in IRAS 09104+4109: one approximately 150 Myr ago, and one ongoing. The X-ray data suggest a photon index of Γ ≃ 1.8 and a line-of-sight column density of N H ≃ 5 × 1023 cm‑2. This argues against a reflection-dominated hard X-ray spectrum, which would have implied a much higher N H and luminosity. The X-ray and infrared data are consistent with a bolometric AGN luminosity of L bol ∼ (0.5–2.5) × 1047 erg s‑1. The X-ray and infrared data are further consistent with coaligned AGN obscurers in which the line of sight “skims” the torus. This is also consistent with the optical spectra, which show both coronal iron lines and broad lines in polarized but not direct light. Combining constraints from the X-ray, optical, and infrared data suggest that the AGN obscurer is within a vertical height of 20 pc, and a radius of 125 pc, of the nucleus.

  18. Intraabdominal cystic lymphangiomas obscured by marked superimposed reactive changes: clinicopathological analysis of a series.

    PubMed

    Hornick, Jason L; Fletcher, Christopher D M

    2005-04-01

    Cystic (or cavernous) lymphangiomas are uncommon tumors that most often occur in the head and neck, axilla, or groin of young children but are detected occasionally in adulthood at various other anatomic sites. When arising in the abdomen, cystic lymphangiomas may present with acute abdominal pain. We have encountered examples of mesenteric and retroperitoneal cystic lymphangiomas associated with such marked superimposed reactive and inflammatory changes that their lymphatic nature is obscured, a situation that is not widely recognized. To further characterize these lesions, 7 abdominal lymphangiomas associated with florid reactive changes were retrieved from the authors' consultation files. There were 5 female patients and 2 male patients (median age, 42 years; range, 1 month to 51 years). Five cases presented in adulthood. Tumor size ranged from 8 to 20 cm (median, 15 cm). Three tumors arose in the mesentery of the small intestine and 4 arose in the retroperitoneum (one of which also involved the posterior mediastinum). Three patients presented with a short history of abdominal pain. Radiological studies revealed large cystic or solid masses; clinical differential diagnoses included sarcoma (2 cases), enteric duplication cyst (2 cases), and cystic tumor not otherwise specified. Grossly, the tumors were generally multiloculated cystic masses associated with areas of fat necrosis and hemorrhage. The cysts often contained thick, gelatinous, or milky fluid. Histologically, all cases showed extensive areas of granulation tissue, most also including a floridly cellular reactive myofibroblastic proliferation, obscuring the lymphatic nature of the lesion. Two cases contained extensive areas of xanthogranulomatous inflammation. In foci where the underlying lesion could be discerned, the tumors were composed of cystically dilated lymphatic spaces, some of which were partially invested by a layer of smooth muscle and were associated with occasional lymphoid aggregates. The

  19. GPU-accelerated real-time IR smoke screen simulation and assessment of its obscuration

    NASA Astrophysics Data System (ADS)

    Wu, Xin; Zhang, Jian-qi; Huang, Xi; Liu, De-lian

    2012-01-01

    With the growing demand for the Battlefield Environment Simulation (BES), IR smoke screen, which is computationally expensive and absolutely indispensable, should be modeled true to life and correct in its thermal radiation characteristics. This paper analyzes the features of an IR smoke screen, and represents an IR smoke screen model based on light extinction, particle dispersion and temperature attenuation, which is calculated by GPU and rendered to screen in real time. Thus a method considering both the real-life in profile and the real-time in efficiency is presented. Additionally, the comparison between the simulated results and the measured data is made to verify the correctness of the smoke screen's obscuration, which illustrates the effect of its interference feature in an infrared scene.

  20. Covering factors of the dusty obscurers in radio-loud and radio-quiet quasars

    NASA Astrophysics Data System (ADS)

    Gupta, Maitrayee; Sikora, Marek; Nalewajko, Krzysztof

    2016-09-01

    We compare covering factors of circumnuclear dusty obscurers in radio-loud and radio-quiet quasars. The radio-loud quasars are represented by a sample of FR II quasars obtained by cross-matching a catalog of the FR II radio sources selected by van Velzen et al. with the SDSS DR7 catalog of quasars. Covering factors of FR II quasars are compared with covering factors of the radio-quiet quasars matched with them in redshift, black hole mass, and Eddington-ratio. We found that covering factors, proxied by the infrared-to-bolometric luminosity ratio, are on average slightly smaller in FR II quasars than in radio-quiet quasars, however, this difference is statistically significant only for the highest Eddington ratios. For both samples, no statistically significant dependence of a median covering factor on Eddington ratio, black hole mass, nor redshift can be claimed.

  1. "Lansania Journal of Arachnology and Zoology" - a rare and obscure Japanese natural history journal.

    PubMed

    Tennent, W John; Yasuda, Masatoshi; Morimoto, Katsura

    2008-01-01

    Publication data relating to a rare and obscure Japanese journal "Lansania Journal of Arachnology and Zoology" (1929-1941) are examined. Available facts, together with a substantial body of circumstantial and anecdotal evidence suggest that many planned issues, including several cited by independent sources as having been published, were not published. Some biographical data relating to the editor, Kyukichi Kishida (1888-1968), are provided. Titles of all papers known to have been published in "Lansania," with page numbers and claimed publication dates are presented, together with a list of 113 new zoological names proposed in the journal. Known library holdings of the journal worldwide are indicated. Details are provided of unpublished manuscripts in proof obtained from Kishida in the 1960s. The strong probability that some printed publication dates are inaccurate is discussed in detail.

  2. Small bowel Dieulafoy lesions: An uncommon cause of obscure bleeding in cirrhosis.

    PubMed

    Holleran, Grainne; Hussey, Mary; McNamara, Deirdre

    2016-08-25

    Dieulafoy lesions (DLs) are an uncommon cause of gastrointestinal bleeding, accounting for up to 2% of cases overall. They are largely under recognised and difficult to treat. Up to 95% occur in the stomach, and only case reports document their occurrence in the small bowel (SB). Little is known about their pathophysiology, although there have been associations made previously with chronic liver disease, thought to be due to the erosive effects of alcohol on the mucosa overlying the abnormally dilated vessels. We present a case series of 4 patients with a long duration of obscure gastrointestinal bleeding, who were diagnosed with small intestinal DLs and incidentally diagnosed with chronic liver disease. The histories describe the challenges in both diagnosis and treatment of small intestinal DLs. Our case series suggest a previously unreported link between chronic liver disease and SB DLs which may be due to anatomical vasculature changes or a shift in angiogenic factors as a consequence of portal hypertension or liver cirrhosis.

  3. Small bowel Dieulafoy lesions: An uncommon cause of obscure bleeding in cirrhosis

    PubMed Central

    Holleran, Grainne; Hussey, Mary; McNamara, Deirdre

    2016-01-01

    Dieulafoy lesions (DLs) are an uncommon cause of gastrointestinal bleeding, accounting for up to 2% of cases overall. They are largely under recognised and difficult to treat. Up to 95% occur in the stomach, and only case reports document their occurrence in the small bowel (SB). Little is known about their pathophysiology, although there have been associations made previously with chronic liver disease, thought to be due to the erosive effects of alcohol on the mucosa overlying the abnormally dilated vessels. We present a case series of 4 patients with a long duration of obscure gastrointestinal bleeding, who were diagnosed with small intestinal DLs and incidentally diagnosed with chronic liver disease. The histories describe the challenges in both diagnosis and treatment of small intestinal DLs. Our case series suggest a previously unreported link between chronic liver disease and SB DLs which may be due to anatomical vasculature changes or a shift in angiogenic factors as a consequence of portal hypertension or liver cirrhosis.

  4. Resurrection of the Island Rule: Human-Driven Extinctions Have Obscured a Basic Evolutionary Pattern.

    PubMed

    Faurby, Søren; Svenning, Jens-Christian

    2016-06-01

    Islands are or have been occupied by unusual species, such as dwarf proboscideans and giant rodents. The discussion of the classical but controversial island rule-which states that mammalian body sizes converge on intermediate sizes on islands-has been stimulated by these unusual species. In this study, we use an unprecedented global data set of the distributions and body sizes of late Quaternary mammal species and a novel analytical method to analyze body size evolution on islands. The analyses produced strong support for the island rule. Islands have suffered massive human-driven losses of species, and we found that the support for the island rule was substantially stronger when the many late Quaternary extinct species were also considered (particularly the tendency for dwarfing in large taxa). The decisive support for the island rule in this study confirms that evolution plays out in a markedly different way on islands and that human impact may obscure even fundamental evolutionary patterns. PMID:27172600

  5. Multiple-return laser radar for three-dimensional imaging through obscurations

    NASA Astrophysics Data System (ADS)

    Schilling, Bradley W.; Barr, Dallas N.; Templeton, Glen C.; Mizerka, Lawrence J.; Trussell, C. Ward

    2002-05-01

    A compact imaging laser radar was constructed and tested to investigate phenomenological issues in targeting, especially cases involving imaging through obscurations such as foliage and camouflage netting. The laser radar employs a Nd:YAG microchip laser that operates at a wavelength of 1.06 mum and produces pulses of 1.2-ns duration at a 3-kHz rate. The detector is a commercial indium gallium arsenide avalanche photodiode. A single computer controls the scanning mirrors and performs the digitization of the returning signal at 2 giga samples/s. A detailed description of the laser radar is presented as well as results from field experiments that examined its range accuracy capability and its ability to image a target through camouflage. Results of data collected from deciduous tree lines are also discussed to characterize the presence and quantity of multiple returns.

  6. Therapeutic or spontaneous Helicobacter pylori eradication can obscure magnifying narrow-band imaging of gastric tumors

    PubMed Central

    Kobayashi, Masaaki; Hashimoto, Satoru; Mizuno, Ken-ichi; Takeuchi, Manabu; Sato, Yuichi; Watanabe, Gen; Ajioka, Yoichi; Azumi, Motoi; Akazawa, Kouhei; Terai, Shuji

    2016-01-01

    Background and study aims: We previously reported that narrow-band imaging with magnifying endoscopy (NBI-ME) revealed a unique “gastritis-like” appearance in approximately 40 % of early gastric cancers after Helicobacter pylori eradication. Because rates of gastric cancer are increasing in patients with non-persistent infection of H. pylori, we aimed to clarify contribution factors to obscure tumors after therapeutic or spontaneous eradication. Patients and methods: NBI-ME findings were examined retrospectively in 194 differentiated-type adenocarcinomas from H. pylori-negative patients with prior eradication therapy (83 patients) or without prior eradication therapy (72 patients). A gastritis-like appearance under NBI-ME was defined as an orderly microsurface structure and/or loss of clear demarcation with resemblance to the adjacent, non-cancerous mucosa. The correlation of this phenomenon with the degree of atrophic gastritis, determined both histologically in the adjacent mucosa and endoscopically, was evaluated. Results: The tumor-obscuring gastritis-like appearance was observed in 42 % and 23 % of the patients in the H. pylori eradication and non-eradication groups, respectively. The development of this appearance was affected by the histological grade of atrophy (P = 0.003) and intestinal metaplasia (P < 0.001) on univariate analysis. Multivariate analysis revealed an odds ratio of 0.25 (95 % confidence interval 0.10 – 0.61, P = 0.002) for an endoscopically severe extent of atrophy, independently of eradication therapy. Conclusions: An endoscopically mild or moderate extent of atrophy is associated with a gastritis-like appearance under NBI-ME in currently H. pylori-negative gastric cancers. Surveillance endoscopy should be performed carefully after successful eradication or spontaneous elimination of H. pylori, particularly in patients with non-severe atrophic background mucosa. PMID:27556076

  7. A New Black Hole Mass Estimate for Obscured Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Minezaki, Takeo; Matsushita, Kyoko

    2015-04-01

    We propose a new method for estimating the mass of a supermassive black hole, applicable to obscured active galactic nuclei (AGNs). This method estimates the black hole mass using the width of the narrow core of the neutral FeKα emission line in X-rays and the distance of its emitting region from the black hole based on the isotropic luminosity indicator via the luminosity scaling relation. Assuming the virial relation between the locations and the velocity widths of the neutral FeKα line core and the broad Hβ emission line, the luminosity scaling relation of the neutral FeKα line core emitting region is estimated. We find that the velocity width of the neutral FeKα line core falls between that of the broad Balmer emission lines and the corresponding value at the dust reverberation radius for most of the target AGNs. The black hole mass {{M}BH,FeKα } estimated with this method is then compared with other black hole mass estimates, such as the broad emission-line reverberation mass {{M}BH,rev} for type 1 AGNs, the mass {{M}BH,{{H2}O}} based on the H2O maser, and the single-epoch mass estimate {{M}BH,pol} based on the polarized broad Balmer lines for type 2 AGNs. We find that {{M}BH,FeKα } is consistent with {{M}BH,rev} and {{M}BH,pol}, and find that {{M}BH,FeKα } correlates well with {{M}BH,{{H2}O}}. These results suggest that {{M}BH,FeKα } is a potential indicator of the black hole mass for obscured AGNs. In contrast, {{M}BH,FeKα } is systematically larger than {{M}BH,{{H2}O}} by about a factor of 5, and the possible origins are discussed.

  8. Evidence for Fluorescent Fe II Emission from Extended Low Ionization Outflows in Obscured Quasars

    NASA Astrophysics Data System (ADS)

    Wang, Tinggui; Ferland, Gary J.; Yang, Chenwei; Wang, Huiyuan; Zhang, Shaohua

    2016-06-01

    Recent studies have shown that outflows in at least some broad absorption line (BAL) quasars are extended well beyond the putative dusty torus. Such outflows should be detectable in obscured quasars. We present four WISE selected infrared red quasars with very strong and peculiar ultraviolet Fe ii emission lines: strong UV Fe ii UV arising from transitions to ground/low excitation levels, and very weak Fe ii at wavelengths longer than 2800 Å. The spectra of these quasars display strong resonant emission lines, such as C iv, Al iii and Mg ii but sometimes, a lack of non-resonant lines such as C iii], S iii and He ii. We interpret the Fe ii lines as resonantly scattered light from the extended outflows that are viewed nearly edge-on, so that the accretion disk and broad line region are obscured by the dusty torus, while the extended outflows are not. We show that dust free gas exposed to strong radiation longward of 912 Å produces Fe ii emission very similar to that observed. The gas is too cool to collisionally excite Fe ii lines, accounting for the lack of optical emission. The spectral energy distribution from the UV to the mid-infrared can be modeled as emission from a clumpy dusty torus, with UV emission being reflected/scattered light either by the dusty torus or the outflow. Within this scenario, we estimate a minimum covering factor of the outflows from a few to 20% for the Fe ii scattering region, suggesting that Fe ii BAL quasars are at a special stage of quasar evolution.

  9. Localization of obscure gastrointestinal bleeding by technetium 99m-labeled red blood cell scintigraphy.

    PubMed

    Wang, C S; Tzen, K Y; Huang, M J; Wang, J Y; Chen, M F

    1992-01-01

    When a bleeding source from the gastrointestinal (GI) tract cannot be identified with conventional diagnostic studies, it is known as GI bleeding of an obscure origin. In the past three years, in vivo Technetium 99m-labeled red blood cell scintigraphy (RBC scan) has been added to our armamentarium for the diagnosis of obscure GI bleeding. Out of a total of 26 cases, the bleeders could be detected in 12 or 46.2% by RBC scan. The time required ranged from 15 minutes to 24 hours (median, one hour). In 14 patients with active bleeding during the scan period, 11 had positive scans (sensitivity, 78.6%). In 12 patients with inactive bleeding, 11 had negative scans (specificity, 91.7%). Angiography was conducted in nine cases, with all showing negative findings; however, six of them had a positive focus by RBC scan. Laparotomy was performed in seven scan-positive patients, and in three scan-negative patients because of a positive Meckel's scan (two cases) or recurrent bleeding (one case). Of the 12 scan-positive patients, incorrect localization was noted in two patients due to rapid transit of the labeled RBC in the small bowel. False localization could be prevented by shortening the sequential imaging interval. It is concluded that an RBC scan is a very sensitive and safe tool for detection of GI bleeding of an intermittent nature, because the bleeder can be monitored for 24 hours after a single injection. It can be used as a preangiographic screening test and to guide the surgeon in surgical planning or decision-making.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1352337

  10. Estimating how inflated or obscured effects of climate affect forecasted species distribution.

    PubMed

    Real, Raimundo; Romero, David; Olivero, Jesús; Estrada, Alba; Márquez, Ana L

    2013-01-01

    Climate is one of the main drivers of species distribution. However, as different environmental factors tend to co-vary, the effect of climate cannot be taken at face value, as it may be either inflated or obscured by other correlated factors. We used the favourability models of four species (Alytes dickhilleni, Vipera latasti, Aquila fasciata and Capra pyrenaica) inhabiting Spanish mountains as case studies to evaluate the relative contribution of climate in their forecasted favourability by using variation partitioning and weighting the effect of climate in relation to non-climatic factors. By calculating the pure effect of the climatic factor, the pure effects of non-climatic factors, the shared climatic effect and the proportion of the pure effect of the climatic factor in relation to its apparent effect (ρ), we assessed the apparent effect and the pure independent effect of climate. We then projected both types of effects when modelling the future favourability for each species and combination of AOGCM-SRES (two Atmosphere-Ocean General Circulation Models: CGCM2 and ECHAM4, and two Special Reports on Emission Scenarios (SRES): A2 and B2). The results show that the apparent effect of climate can be either inflated (overrated) or obscured (underrated) by other correlated factors. These differences were species-specific; the sum of favourable areas forecasted according to the pure climatic effect differed from that forecasted according to the apparent climatic effect by about 61% on average for one of the species analyzed, and by about 20% on average for each of the other species. The pure effect of future climate on species distributions can only be estimated by combining climate with other factors. Transferring the pure climatic effect and the apparent climatic effect to the future delimits the maximum and minimum favourable areas forecasted for each species in each climate change scenario.

  11. Suzaku follow-up of heavily obscured active galactic nuclei detected in Swift/BAT survey: NGC 1106, UGC 03752, and NGC 2788A

    NASA Astrophysics Data System (ADS)

    Tanimoto, Atsushi; Ueda, Yoshihiro; Kawamuro, Taiki; Ricci, Claudio

    2016-06-01

    We present the broad-band (0.5-100 keV) spectra of three heavily obscured active galactic nuclei (AGNs), NGC 1106, UGC 03752, and NGC 2788A, observed with Suzaku and the Swift/Burst Alert Telescope (BAT). The targets are selected from the Swift/BAT 70-month catalog on the basis of their high hardness ratio between above and below 10 keV, and their X-ray spectra are reported here for the first time. We apply three models: a conventional model utilizing an analytic reflection code, and two Monte Carlo based torus models with a doughnut-like geometry (MYTorus: Murphy & Yaqoob, 2009, MNRAS, 397, 1549) and with a nearly spherical geometry (Ikeda torus: Ikeda et al., 2009, ApJ, 692, 608). The three models can successfully reproduce the spectra, and the Ikeda torus model gives a better description than the MYTorus model in all targets. We identify NGC 1106 and NGC 2788A as Compton-thick AGNs. We point out that the common presence of unabsorbed reflection components below 7.1 keV in obscured AGNs, as observed from UGC 03752, is evidence for clumpy tori. This implies that detailed studies utilizing clumpy torus models are required to reach correct interpretation of the X-ray spectra of AGNs.

  12. Sarcomatoid carcinoma of the jejunum presenting as obscure gastrointestinal bleeding in a patient with a history of gliosarcoma

    PubMed Central

    Alfonso Puentes, Nidia; Jimenez-Alfaro Larrazabal, Carmen; García Higuera, Maria Isabel

    2014-01-01

    Small bowel malignant tumors are rare and sarcomatoid carcinomas have rarely been reported at this site. We report a 56-year-old woman, with history of an excised gliosarcoma, who presented with recurrent obscure gastrointestinal bleeding. She underwent endoscopy and colonoscopy, which failed to identify the cause of the bleeding. The abdominal computed tomography scan located a tumor in the small bowel. Pathology revealed a jejunal sarcomatoid carcinoma. She developed tumor recurrence and multiple liver metastases shortly after surgery. Immunohistochemistry is required for accurate diagnosis. Sarcomatoid carcinoma is a rare cause of obscure gastrointestinal bleeding, which is associated with a poor prognosis. PMID:24759341

  13. Nitrogen and Carbon Flows Estimated by 15N and 13C Pulse-Chase Labeling during Regrowth of Alfalfa.

    PubMed Central

    Avice, J. C.; Ourry, A.; Lemaire, G.; Boucaud, J.

    1996-01-01

    The flow of 15N and 13C from storage compounds in organs remaining after defoliation (sources) to regrowing tissue (sinks), and 13C losses through root or shoot respiration were assessed by pulse-chase labeling during regrowth of alfalfa (Medicago sativa L.) following shoot removal. A total of 73% of labeled C and 34% of labeled N were mobilized in source organs within 30 d. Although all of the 15N from source organs was recovered in the regrowing tissue, much of the 13C was lost, mainly as CO2 respired from the root (61%) or shoot (8%), and was found to a lesser extent in sink tissue (5%). After 3, 10, or 30 d of regrowth, 87, 66, and 52% of shoot N, respectively, was derived from source tissue storage compounds; the rest resulted from translocation of fixed N2. Overall results suggest that most shoot C was linked to photosynthetic activity rather than being derived from mobilization of stored C in source organs. Furthermore, isotopic analysis of different chemical fractions of plant tissue suggests that between 14 and 58% of the shoot C derived from source tissues was linked to the mobilization of N compounds, not carbohydrates. PMID:12226391

  14. Costs of locomotion in polar bears: when do the costs outweigh the benefits of chasing down terrestrial prey?

    PubMed Central

    Gormezano, Linda J.; McWilliams, Scott R.; Iles, David T.; Rockwell, Robert F.

    2016-01-01

    Trade-offs between locomotory costs and foraging gains are key elements in determining constraints on predator–prey interactions. One intriguing example involves polar bears pursuing snow geese on land. As climate change forces polar bears to spend more time ashore, they may need to expend more energy to obtain land-based food. Given that polar bears are inefficient at terrestrial locomotion, any extra energy expended to pursue prey could negatively impact survival. However, polar bears have been regularly observed engaging in long pursuits of geese and other land animals, and the energetic worth of such behaviour has been repeatedly questioned. We use data-driven energetic models to examine how energy expenditures vary across polar bear mass and speed. For the first time, we show that polar bears in the 125–235 kg size range can profitably pursue geese, especially at slower speeds. We caution, however, that heat build-up may be the ultimate limiting factor in terrestrial chases, especially for larger bears, and this limit would be reached more quickly with warmer environmental temperatures. PMID:27757238

  15. The Nudix Hydrolase CDP-Chase, a CDP-Choline Pyrophosphatase, Is an Asymmetric Dimer with Two Distinct Enzymatic Activities

    SciTech Connect

    Duong-Ly, Krisna C.; Gabelli, Sandra B.; Xu, WenLian; Dunn, Christopher A.; Schoeffield, Andrew J.; Bessman, Maurice J.; Amzel, L. Mario

    2011-09-06

    A Nudix enzyme from Bacillus cereus catalyzes the hydrolysis of CDP-choline to produce CMP and phosphocholine. Here, we show that in addition, the enzyme has a 3{prime} {yields} 5{prime} RNA exonuclease activity. The structure of the free enzyme, determined to a 1.8-{angstrom} resolution, shows that the enzyme is an asymmetric dimer. Each monomer consists of two domains, an N-terminal helical domain and a C-terminal Nudix domain. The N-terminal domain is placed relative to the C-terminal domain such as to result in an overall asymmetric arrangement with two distinct catalytic sites: one with an 'enclosed' Nudix pyrophosphatase site and the other with a more open, less-defined cavity. Residues that may be important for determining the asymmetry are conserved among a group of uncharacterized Nudix enzymes from Gram-positive bacteria. Our data support a model where CDP-choline hydrolysis is catalyzed by the enclosed Nudix site and RNA exonuclease activity is catalyzed by the open site. CDP-Chase is the first identified member of a novel Nudix family in which structural asymmetry has a profound effect on the recognition of substrates.

  16. The Swift BAT Survey Detects Two Optical Broad Line, X-Ray Heavily Obscured Active Galaxies: NVSS 193013+341047 and IRAS 05218-1212

    NASA Astrophysics Data System (ADS)

    Hogg, J. Drew; Winter, Lisa M.; Mushotzky, Richard F.; Reynolds, Christopher S.; Trippe, Margaret

    2012-06-01

    The Swift Burst Alert Telescope (BAT) is discovering interesting new objects while monitoring the sky in the 14-195 keV band. Here we present the X-ray properties and spectral energy distributions (SEDs) for two unusual active galactic nucleus sources. Both NVSS 193013+341047 and IRAS 05218-1212 are absorbed, Compton-thin, but heavily obscured (N H ~ 1023 cm-2), X-ray sources at redshifts <0.1. The SEDs reveal these galaxies to be very red, with high extinction in the optical and UV. A similar SED is seen for the extremely red objects (EROs) detected in the higher redshift universe. This suggests that these unusual BAT-detected sources are a low-redshift (z Lt 1) analog to EROs, which recent evidence suggests are a class of the elusive type II quasars. Studying the multi-wavelength properties of these sources may reveal the properties of their high-redshift counterparts.

  17. Updated measurements of the dark matter halo masses of obscured quasars with improved WISE and Planck data

    NASA Astrophysics Data System (ADS)

    DiPompeo, M. A.; Hickox, R. C.; Myers, A. D.

    2016-02-01

    Using the most recent releases of WISE and Planck data, we perform updated measurements of the bias and typical dark matter halo mass of infrared (IR)-selected obscured and unobscured quasars, using the angular autocorrelation function and cosmic microwave background lensing cross-correlations. Since our recent work of this kind, the WISE ALLWISE catalogue was released with improved photometry, and the Planck mission was completed and released improved products. These new data provide a more reliable measurement of the quasar bias and provide an opportunity to explore the role of changing survey pipelines in results downstream. We present a comparison of IR colour-selected quasars, split into obscured and unobscured populations based on optical-IR colours, selected from two versions of the WISE data. Which combination of data is used impacts the final results, particularly for obscured quasars, both because of mitigation of some systematics and because the newer catalogue provides a slightly different sample. We show that ALLWISE data is superior in several ways, though there may be some systematic trends with Moon contamination that were not present in the previous catalogue. We opt currently for the most conservative sample that meet our selection criteria in both the previous and new WISE catalogues. We measure a higher bias and halo mass for obscured quasars (bobsc ˜ 2.1, bunob ˜ 1.8) - at odds with simple orientation models - but at a reduced significance (˜1.5σ) as compared to our work with previous survey data.

  18. Atmospheric propagation effects through natural and man-made obscurants for visible to MM-wave radiation

    NASA Astrophysics Data System (ADS)

    1993-11-01

    Modern, precision-guided weapons require that guidance and target acquisition/recognition systems take into account the effects of the propagation environment. Successful performance must be obtained under adverse weather conditions such as haze, clouds, fog, rain, and snow and under adverse battlefield conditions such as dust, smoke, and man-made obscurants. Sensors operate at wavelengths ranging across the millimeter, IR, and the visible regions of the electromagnetic spectrum. Propagation effects vary drastically over this wavelength span and systems may employ a combination of sensors to mitigate adverse environmental conditions. The effectiveness of countermeasures such as multispectral obscurants and multispectral camouflage also depends on atmospheric properties. System performance is measured in terms of probability of detection, probability of recognition, and, ultimately, in terms of probability of a kill. A partial listing of the processes that affect theses probabilities and, in turn, are affected by the propagation environment includes extinction, angles and amplitude scintillation, target to background contrast, contrast transmission, and clutter characteristics. The symposium addresses the following topics: natural obscurants, multispectral camouflage, man-made obscurants and battlefield-induced phenomena, and target and background signatures.

  19. Disentangling Dominance: Obscured AGN Activity versus Star Formation in BPT-Composites

    NASA Astrophysics Data System (ADS)

    Trouille, Laura

    2011-11-01

    Approximately 20% of SDSS emission-line galaxies (ELG) lie in the BPT-comp regime, between the Kauffmann et al. (2003) empirically determined SF-dominated regime and the Kewley et al. (2001) theoretically predicted AGN-dominated regime. BPT-AGN, on the other hand, make up only 11% of the ELG population. Whether to include the significant number of BPT-comp in samples of AGN or samples of star-forming galaxies is an open question and has important implications for galaxy evolution studies, metallicity studies, etc. Using a large pectroscopic sample of GOODS-N and LH galaxies with deep Chandra imaging, we perform an X-ray stacking analysis of BPT-comp. We find the stacked signal to be X-ray hard. This X-ray hardness can be indicative of obscured AGN activity or the presence of HMXBs associated with ongoing star formation. In order to distinguish between these scenarios, we perform an IR stacking analysis using Spitzer 24 micron data. The stacked BPT-comp lies well above the expected value for L_x/L_IR for pure star-forming galaxies; similarly for the X-ray detected BPT-comp. We also find that the BPT-comp lie in the AGN-dominated regime of our new TBT diagnostic, which uses [NeIII]/[OII] versus rest-frame g-z colour to identify AGN and star forming galaxies out to z=1.4. [NeIII], which has a higher ionisation potential than other commonly used forbidden emission lines, appears to foster a more reliable selection of AGN-dominated galaxies. These findings suggest that both the X-ray and optical signal in BPT-comp are dominated by obscured or low accretion rate AGN activity rather than star formation. This is in contrast to claims by previous optical emission-line studies that the signal in BPT-comp is dominated by star-formation activity. Therefore, we recommend that groups carefully consider the impact of excluding or including BPT-comp on the interpretation of their results. For example, for studies involving determining the bolometric contribution from AGN activity

  20. THE XMM-NEWTON WIDE-FIELD SURVEY IN THE COSMOS FIELD (XMM-COSMOS): DEMOGRAPHY AND MULTIWAVELENGTH PROPERTIES OF OBSCURED AND UNOBSCURED LUMINOUS ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Brusa, M.; Cappelluti, N.; Merloni, A.; Bongiorno, A.; Civano, F.; Elvis, M.; Hao, H.; Comastri, A.; Zamorani, G.; Gilli, R.; Miyaji, T.; Salvato, M.; Hasinger, G.; Fiore, F.; Mainieri, V.; Capak, P.; Jahnke, K.; Koekemoer, A. M.; Ilbert, O.; Le Floc'h, E.

    2010-06-10

    We report the final optical identifications of the medium-depth ({approx}60 ks), contiguous (2 deg{sup 2}) XMM-Newton survey of the COSMOS field. XMM-Newton has detected {approx}1800 X-ray sources down to limiting fluxes of {approx}5 x 10{sup -16}, {approx}3 x 10{sup -15}, and {approx}7 x 10{sup -15} erg cm{sup -2} s{sup -1} in the 0.5-2 keV, 2-10 keV, and 5-10 keV bands, respectively ({approx}1 x 10{sup -15}, {approx}6 x 10{sup -15}, and {approx}1 x 10{sup -14} erg cm{sup -2} s{sup -1}, in the three bands, respectively, over 50% of the area). The work is complemented by an extensive collection of multiwavelength data from 24 {mu}m to UV, available from the COSMOS survey, for each of the X-ray sources, including spectroscopic redshifts for {approx}>50% of the sample, and high-quality photometric redshifts for the rest. The XMM and multiwavelength flux limits are well matched: 1760 (98%) of the X-ray sources have optical counterparts, 1711 ({approx}95%) have IRAC counterparts, and 1394 ({approx}78%) have MIPS 24 {mu}m detections. Thanks to the redshift completeness (almost 100%) we were able to constrain the high-luminosity tail of the X-ray luminosity function confirming that the peak of the number density of log L{sub X} > 44.5 active galactic nuclei (AGNs) is at z {approx} 2. Spectroscopically identified obscured and unobscured AGNs, as well as normal and star-forming galaxies, present well-defined optical and infrared properties. We devised a robust method to identify a sample of {approx}150 high-redshift (z > 1), obscured AGN candidates for which optical spectroscopy is not available. We were able to determine that the fraction of the obscured AGN population at the highest (L{sub X} > 10{sup 44} erg s{sup -1}) X-ray luminosity is {approx}15%-30% when selection effects are taken into account, providing an important observational constraint for X-ray background synthesis. We studied in detail the optical spectrum and the overall spectral energy distribution of a

  1. NuSTAR and XMM-Newton Observations of Luminous, Heavily Obscured, WISE-selected Quasars at z ~ 2

    NASA Astrophysics Data System (ADS)

    Stern, D.; Lansbury, G. B.; Assef, R. J.; Brandt, W. N.; Alexander, D. M.; Ballantyne, D. R.; Baloković, M.; Bauer, F. E.; Benford, D.; Blain, A.; Boggs, S. E.; Bridge, C.; Brightman, M.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Del Moro, A.; Eisenhardt, P. R. M.; Gandhi, P.; Griffith, R. L.; Hailey, C. J.; Harrison, F. A.; Hickox, R. C.; Jarrett, T. H.; Koss, M.; Lake, S.; LaMassa, S. M.; Luo, B.; Tsai, C.-W.; Urry, C. M.; Walton, D. J.; Wright, E. L.; Wu, J.; Yan, L.; Zhang, W. W.

    2014-10-01

    We report on a NuSTAR and XMM-Newton program that has observed a sample of three extremely luminous, heavily obscured WISE-selected active galactic nuclei (AGNs) at z ~ 2 across a broad X-ray band (0.1 - 79 keV). The parent sample, selected to be faint or undetected in the WISE 3.4 μm (W1) and 4.6 μm (W2) bands but bright at 12 μm (W3) and 22 μm (W4), are extremely rare, with only ~1000 so-called "W1W2-dropouts" across the extragalactic sky. Optical spectroscopy reveals typical redshifts of z ~ 2 for this population, implying rest-frame mid-IR luminosities of νL ν(6 μm) ~ 6 × 1046 erg s-1 and bolometric luminosities that can exceed L bol ~ 1014 L ⊙. The corresponding intrinsic, unobscured hard X-ray luminosities are L(2-10 keV) ~ 4 × 1045 erg s-1 for typical quasar templates. These are among the most AGNs known, though the optical spectra rarely show evidence of a broad-line region and the selection criteria imply heavy obscuration even at rest-frame 1.5 μm. We designed our X-ray observations to obtain robust detections for gas column densities N H <= 1024 cm-2. In fact, the sources prove to be fainter than these predictions. Two of the sources were observed by both NuSTAR and XMM-Newton, with neither being detected by NuSTAR (f 3-24 keV <~ 10-13 erg cm-2 s-1), and one being faintly detected by XMM-Newton (f 0.5-10 keV ~ 5 × 10-15 erg cm-2 s-1). A third source was observed only with XMM-Newton, yielding a faint detection (f 0.5-10 keV ~ 7 × 10-15 erg cm-2 s-1). The X-ray data imply these sources are either X-ray weak, or are heavily obscured by column densities N H >~ 1024 cm-2. The combined X-ray and mid-IR analysis seems to favor this second possibility, implying the sources are extremely obscured, consistent with Compton-thick, luminous quasars. The discovery of a significant population of heavily obscured, extremely luminous AGNs would not conform to the standard paradigm of a receding torus, in which more luminous quasars are less likely to be

  2. Infrared Spectroscopy of a Massive Obscured Star Cluster in the Antennae Galaxies (NGC 4038/9) with NIRSPEC.

    PubMed

    Gilbert; Graham; McLean; Becklin; Figer; Larkin; Levenson; Teplitz; Wilcox

    2000-04-10

    We present infrared spectroscopy of the Antennae galaxies (NGC 4038/9) with the near-infrared spectrometer (NIRSPEC) at the W. M. Keck Observatory. We imaged the star clusters in the vicinity of the southern nucleus (NGC 4039) with 0&farcs;39 seeing in the K band using NIRSPEC's slit-viewing camera. The brightest star cluster revealed in the near-IR [MK&parl0;0&parr0; approximately -17.9] is insignificant optically but is coincident with the highest surface brightness peak in the mid-IR (12-18 µm) Infrared Space Observatory image presented by Mirabel et al. We obtained high signal-to-noise ratio 2.03-2.45 µm spectra of the nucleus and the obscured star cluster at R approximately 1900. The cluster is very young ( approximately 4 Myr), massive (M approximately 16x106 M middle dot in circle), and compact (with a density of approximately 115 M middle dot in circle pc-3 within a 32 pc half-light radius), assuming a Salpeter initial mass function (0.1-100 M middle dot in circle). Its hot stars have a radiation field characterized by Teff approximately 39,000 K, and they ionize a compact H ii region with ne approximately 104 cm-3. The stars are deeply embedded in gas and dust (AV approximately 9-10 mag), and their strong far-ultraviolet field powers a clumpy photodissociation region with densities nH greater, similar105 cm-3 on scales of approximately 200 pc, radiating LH21-0S&parl0;1&parr0;=9600 L middle dot in circle.

  3. Infrared Spectroscopy of a Massive Obscured Star Cluster in the Antennae Galaxies (NGC 4038/9) with NIRSPEC.

    PubMed

    Gilbert; Graham; McLean; Becklin; Figer; Larkin; Levenson; Teplitz; Wilcox

    2000-04-10

    We present infrared spectroscopy of the Antennae galaxies (NGC 4038/9) with the near-infrared spectrometer (NIRSPEC) at the W. M. Keck Observatory. We imaged the star clusters in the vicinity of the southern nucleus (NGC 4039) with 0&farcs;39 seeing in the K band using NIRSPEC's slit-viewing camera. The brightest star cluster revealed in the near-IR [MK&parl0;0&parr0; approximately -17.9] is insignificant optically but is coincident with the highest surface brightness peak in the mid-IR (12-18 µm) Infrared Space Observatory image presented by Mirabel et al. We obtained high signal-to-noise ratio 2.03-2.45 µm spectra of the nucleus and the obscured star cluster at R approximately 1900. The cluster is very young ( approximately 4 Myr), massive (M approximately 16x106 M middle dot in circle), and compact (with a density of approximately 115 M middle dot in circle pc-3 within a 32 pc half-light radius), assuming a Salpeter initial mass function (0.1-100 M middle dot in circle). Its hot stars have a radiation field characterized by Teff approximately 39,000 K, and they ionize a compact H ii region with ne approximately 104 cm-3. The stars are deeply embedded in gas and dust (AV approximately 9-10 mag), and their strong far-ultraviolet field powers a clumpy photodissociation region with densities nH greater, similar105 cm-3 on scales of approximately 200 pc, radiating LH21-0S&parl0;1&parr0;=9600 L middle dot in circle. PMID:10727391

  4. Evidence for a Wide Range of Ultraviolet Obscuration in z ~ 2 Dusty Galaxies from the GOODS-Herschel Survey

    NASA Astrophysics Data System (ADS)

    Penner, Kyle; Dickinson, Mark; Pope, Alexandra; Dey, Arjun; Magnelli, Benjamin; Pannella, Maurilio; Altieri, Bruno; Aussel, Herve; Buat, Veronique; Bussmann, Shane; Charmandaris, Vassilis; Coia, Daniela; Daddi, Emanuele; Dannerbauer, Helmut; Elbaz, David; Hwang, Ho Seong; Kartaltepe, Jeyhan; Lin, Lihwai; Magdis, Georgios; Morrison, Glenn; Popesso, Paola; Scott, Douglas; Valtchanov, Ivan

    2012-11-01

    Dusty galaxies at z ~ 2 span a wide range of relative brightness between rest-frame mid-infrared (8 μm) and ultraviolet wavelengths. We attempt to determine the physical mechanism responsible for this diversity. Dust-obscured galaxies (DOGs), which have rest-frame mid-IR to UV flux density ratios >~ 1000, might be abnormally bright in the mid-IR, perhaps due to prominent emission from active galactic nuclei and/or polycyclic aromatic hydrocarbons, or abnormally faint in the UV. We use far-infrared data from the GOODS-Herschel survey to show that most DOGs with 1012 L ⊙ <~ L IR <~ 1013 L ⊙ are not abnormally bright in the mid-IR when compared to other dusty galaxies with similar IR (8-1000 μm) luminosities. We observe a relation between the median IR to UV luminosity ratios and the median UV continuum power-law indices for these galaxies, and we find that only 24% have specific star formation rates that indicate the dominance of compact star-forming regions. This circumstantial evidence supports the idea that the UV- and IR-emitting regions in these galaxies are spatially coincident, which implies a connection between the abnormal UV faintness of DOGs and dust obscuration. We conclude that the range in rest-frame mid-IR to UV flux density ratios spanned by dusty galaxies at z ~ 2 is due to differing amounts of UV obscuration. Of galaxies with these IR luminosities, DOGs are the most obscured. We attribute differences in UV obscuration to either (1) differences in the degree of alignment between the spatial distributions of dust and massive stars or (2) differences in the total dust content. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  5. EVIDENCE FOR A WIDE RANGE OF ULTRAVIOLET OBSCURATION IN z {approx} 2 DUSTY GALAXIES FROM THE GOODS-HERSCHEL SURVEY

    SciTech Connect

    Penner, Kyle; Dickinson, Mark; Dey, Arjun; Kartaltepe, Jeyhan; Pope, Alexandra; Magnelli, Benjamin; Pannella, Maurilio; Aussel, Herve; Daddi, Emanuele; Elbaz, David; Buat, Veronique; Bussmann, Shane; Hwang, Ho Seong; Charmandaris, Vassilis; Dannerbauer, Helmut; Lin Lihwai; Magdis, Georgios; Morrison, Glenn; and others

    2012-11-01

    Dusty galaxies at z {approx} 2 span a wide range of relative brightness between rest-frame mid-infrared (8 {mu}m) and ultraviolet wavelengths. We attempt to determine the physical mechanism responsible for this diversity. Dust-obscured galaxies (DOGs), which have rest-frame mid-IR to UV flux density ratios {approx}> 1000, might be abnormally bright in the mid-IR, perhaps due to prominent emission from active galactic nuclei and/or polycyclic aromatic hydrocarbons, or abnormally faint in the UV. We use far-infrared data from the GOODS-Herschel survey to show that most DOGs with 10{sup 12} L {sub Sun} {approx}< L {sub IR} {approx}< 10{sup 13} L {sub Sun} are not abnormally bright in the mid-IR when compared to other dusty galaxies with similar IR (8-1000 {mu}m) luminosities. We observe a relation between the median IR to UV luminosity ratios and the median UV continuum power-law indices for these galaxies, and we find that only 24% have specific star formation rates that indicate the dominance of compact star-forming regions. This circumstantial evidence supports the idea that the UV- and IR-emitting regions in these galaxies are spatially coincident, which implies a connection between the abnormal UV faintness of DOGs and dust obscuration. We conclude that the range in rest-frame mid-IR to UV flux density ratios spanned by dusty galaxies at z {approx} 2 is due to differing amounts of UV obscuration. Of galaxies with these IR luminosities, DOGs are the most obscured. We attribute differences in UV obscuration to either (1) differences in the degree of alignment between the spatial distributions of dust and massive stars or (2) differences in the total dust content.

  6. THE STELLAR CONTENT OF OBSCURED GALACTIC GIANT H II REGIONS. VII. W3

    SciTech Connect

    Navarete, F.; Figueredo, E.; Damineli, A.; Moises, A. P.; Blum, R. D.; Conti, P. S.

    2011-09-15

    Spectrophotometric distances in the K band have been reported by different authors for a number of obscured Galactic H II regions. Almost 50% of them show large discrepancies compared to the classical method using radial velocities measured in the radio spectral region. In order to provide a crucial test of both methods, we selected a target that does not present particular difficulty for any method and which has been measured by as many techniques as possible. The W3 star-forming complex, located in the Perseus arm, offers a splendid opportunity for such a task. We used the Near-Infrared Integral Field Spectrograph on the Frederick C. Gillett Gemini North telescope to classify candidate 'naked photosphere' OB stars based on Two Micron All Sky Survey photometry. Two of the targets are revealed to be mid-O-type main-sequence stars leading to a distance of d = 2.20 kpc. This is in excellent agreement with the spectrophotometric distance derived in the optical band (d = 2.18 pc) and with a measurement of the W3 trigonometric parallax (d = 1.95 kpc). Such results confirm that the spectrophotometric distances in the K band are reliable. The radio-derived kinematic distance, on the contrary, gives a distance twice as large (d = 4.2 kpc). This indicates that this region of the Perseus arm does not follow the Galactic rotation curve, and this may also be the case for other H II regions for which discrepancies have been found.

  7. Small bowel Dieulafoy lesions: An uncommon cause of obscure bleeding in cirrhosis

    PubMed Central

    Holleran, Grainne; Hussey, Mary; McNamara, Deirdre

    2016-01-01

    Dieulafoy lesions (DLs) are an uncommon cause of gastrointestinal bleeding, accounting for up to 2% of cases overall. They are largely under recognised and difficult to treat. Up to 95% occur in the stomach, and only case reports document their occurrence in the small bowel (SB). Little is known about their pathophysiology, although there have been associations made previously with chronic liver disease, thought to be due to the erosive effects of alcohol on the mucosa overlying the abnormally dilated vessels. We present a case series of 4 patients with a long duration of obscure gastrointestinal bleeding, who were diagnosed with small intestinal DLs and incidentally diagnosed with chronic liver disease. The histories describe the challenges in both diagnosis and treatment of small intestinal DLs. Our case series suggest a previously unreported link between chronic liver disease and SB DLs which may be due to anatomical vasculature changes or a shift in angiogenic factors as a consequence of portal hypertension or liver cirrhosis. PMID:27621769

  8. Small bowel Dieulafoy lesions: An uncommon cause of obscure bleeding in cirrhosis.

    PubMed

    Holleran, Grainne; Hussey, Mary; McNamara, Deirdre

    2016-08-25

    Dieulafoy lesions (DLs) are an uncommon cause of gastrointestinal bleeding, accounting for up to 2% of cases overall. They are largely under recognised and difficult to treat. Up to 95% occur in the stomach, and only case reports document their occurrence in the small bowel (SB). Little is known about their pathophysiology, although there have been associations made previously with chronic liver disease, thought to be due to the erosive effects of alcohol on the mucosa overlying the abnormally dilated vessels. We present a case series of 4 patients with a long duration of obscure gastrointestinal bleeding, who were diagnosed with small intestinal DLs and incidentally diagnosed with chronic liver disease. The histories describe the challenges in both diagnosis and treatment of small intestinal DLs. Our case series suggest a previously unreported link between chronic liver disease and SB DLs which may be due to anatomical vasculature changes or a shift in angiogenic factors as a consequence of portal hypertension or liver cirrhosis. PMID:27621769

  9. Boundaries obscured and boundaries reinforced: incorporation as a strategy of occupational enhancement for intensive care.

    PubMed

    Carmel, Simon

    2006-03-01

    Medical dominance is a recurring theme in sociological analyses of healthcare work. One example of a theoretical framework by which the medical profession is said to dominate other healthcare occupations is Turner's (1995: 138) enumeration of the modes of subordination, limitation and exclusion. As Elston (1991) has noted, however, such frameworks tend to be rather speculative and there is not a great deal of evidence on how these strategies are exercised, for example, at a micro-level. There is also a tendency to portray healthcare occupations as monolithic entities, without acknowledging differences within healthcare occupations, and the relationships between them, which can arise in different clinical locales. Through a micro-level analysis of the practice of intensive care, using ethnographic data collected on three intensive care units (ICUs) in England, this paper proposes a hitherto unidentified strategy -incorporation- for medical dominance at a micro-level. Paradoxically, an enhanced position for both intensive care medicine and intensive care nursing arises, relative to proximal healthcare groups. The argument of this paper is that within the ICU an occupational boundary (doctor-nurse) is obscured, while an organisational boundary which differentiates the ICU from the wider hospital is reinforced. Overall, the power relationship between medicine and nursing in intensive care is not 'zero-sum': the influence of both groups in the wider hospital is increased by this strategy of incorporation.

  10. Occult and obscure gastrointestinal bleeding: Causes and diagnostic approach in 2009

    PubMed Central

    Bresci, Giampaolo

    2009-01-01

    Gastrointestinal bleeding can be obscure or occult (OGIB), the causes and diagnostic approach will be discussed in this editorial. The evaluation of OGIB consists on a judicious search of the cause of bleeding, which should be guided by the clinical history and physical findings. The standard approach to patients with OGIB is to directly evaluate the gastrointestinal tract by endoscopy, abdominal computed tomography, angiography, radionuclide scanning, capsule endoscopy. The source of OGIB can be identified in 85%-90%, no bleeding sites will be found in about 5%-10% of cases. Even if the bleedings originating from the small bowel are not frequent in clinical practice (7.6% of all digestive haemorrhages, in our casuistry), they are notoriously difficult to diagnose. In spite of progress, however, a number of OGIB still remain problematic to deal with at present in the clinical context due to both the difficulty in exactly identifying the site and nature of the underlying source and the difficulty in applying affective and durable diagnostic approaches so no single technique has emerged as the most efficient way to evaluate OGIB. PMID:21160643

  11. Jansky VLA Imaging of Heavily Obscured, Luminous Quasars at Redshifts ~2

    NASA Astrophysics Data System (ADS)

    Trapp, Adam; Lonsdale, Carol J.; Patil, Palavi; Whittle, Mark; Lacy, Mark; Lonsdale, Colin J.

    2016-01-01

    We present JVLA A and B array observations in X-band (8-12 GHz) of a sample of radio powerful, bolometrically luminous, but optically obscured quasars. The quasars were selected using a cross-match between WISE mid-IR sources brighter than 7 mJ at 22 mu and NVSS and/or FIRST radio surveys, with a further constraint that the sources were optically faint. The survey aims to select young quasars with young radio sources at redshifts z ~ 1-3. Ultimately, we wish to study the role that radio jets play in quasar driven feedback. Our VLA observations provide fundamental information on radio source size, structure, power and spectral index, all of which shed light on the properties of the young radio source. We will present images and data on 155 objects from our primary sample WISE-NVSS sample of 156.The majority of sources are found to be compact, steep-spectrum, and sub-galactic in scale, with a significant minority of resolved doubles, triples, and core-jets. Using radio data at other wavelengths taken from the literature, we use SED fits to identify or constrain the turn-over frequencies. Combining size and turn-over frequency, the majority of the sources are found to be CSS, GPS or HFPs, consistent with young radio source ages.

  12. The Vector Vortex Coronagraph: sensitivity to central obscuration, low-order aberrations, chromaticism, and polarization

    NASA Astrophysics Data System (ADS)

    Mawet, Dimitri; Pueyo, Laurent; Moody, Dwight; Krist, John; Serabyn, Eugene

    2010-07-01

    The Vector Vortex Coronagraph is a phase-based coronagraph, one of the most efficient in terms of inner working angle, throughput, discovery space, contrast, and simplicity. Using liquid-crystal polymer technology, this new coronagraph has recently been the subject of lab demonstrations in the near-infrared, visible and was also used on sky at the Palomar observatory in the H and K bands (1.65 and 2.2 μm, respectively) to image the brown dwarf companion to HR 7672, and the three extra-solar planets around HR 8799. However, despite these recent successes, the Vector Vortex Coronagraph is, as are most coronagraphs, sensitive to the central obscuration and secondary support structures, low-order aberrations (tip-tilt, focus, etc), bandwidth (chromaticism), and polarization when image-plane wavefront sensing is performed. Here, we consider in detail these sensitivities as a function of the topological charge of the vortex and design features inherent to the manufacturing technology, and show that in practice all of them can be mitigated to meet specific needs.

  13. The Vector Vortex Coronagraph: Sensitivity to Low-Order Aberrations, Central Obscuration, Chromaticism, and Polarization

    NASA Technical Reports Server (NTRS)

    Mawet, Dimitri; Pueyo, Laurent; Moody, Dwight; Krist, John; Serabyn, Eugene

    2010-01-01

    The Vector Vortex Coronagraph is a phase-based coronagraph, one of the most efficient in terms of inner working angle, throughput, discovery space, contrast, and simplicity. Using liquid-crystal polymer technology, this new coronagraph has recently been the subject of lab demonstrations in the near-infrared, visible and was also used on sky at the Palomar observatory in the H and K bands (1.65 and 2.2 micrometers, respectively) to image the brown dwarf companion to HR 7672, and the three extasolar planets around HR 8799. However, despite these recent successes, the Vector Vortex Coronagraph is, as are most coronagraphs, sensitive to the central obscuration and secondary support structures, low-order aberrations (tip-tilt, focus, etc), bandwidth (chromaticism), and polarization when image-plane wavefront sensing is performed. Here, we consider in detail these sensitivities as a function of the topological charge of the vortex and design properties inherent to the manufacturing technology, and show that in practice all of them can be mitigated to meet specific needs.

  14. [Actinic enteritis as a cause of digestive bleeding of obscure origin].

    PubMed

    Vásquez, Luis; Guevara, Julissa; Aguilar, Victor; Menéndez, Monica; Bravo, Eduar; Guzman Rojas, Patricia; Pichilingue, Catherina; Zegarra, Arturo; Huerta-Mercado, Jorge; Pinto, José; Prochazka, Ricardo; Valenzuela, Vanessa; Bussalleu, Alejandro

    2016-01-01

    Chronic actinic enteritis is a malfunction of the small bowel, occurring in the 6 months post-radiotherapy, and it can be manifestated as malabsortion, stenosis, fistula formation, local abscesses, perforation and bleeding, We report a case of an elderly patient who presents an episode of obscure gastrointestinal bleeding (OGIB) secondary to actinic enteritis. She is a 64-year- old female patient with the past medical history of cervical cancer who received radiotherapy and brachytherapy. One year after the treatment, the patient presents a chronic episode of melena and symptomatic anemia and 1 week before the admission she had hematochezia. At admission she has hemodynamic instability with a hemoglobin value of 2.7 gr/dl. We did an upper endoscopy, a colonoscopy and abdomino-pelvic tomography without any findings of the bleeding’s source. Reason why an endoscopic capsule was done, showing bleeding areas in the medial and distal small bowel. The patient had another gastrointestinal bleeding requiring a surgery where they decide to do a resection of the small bowel and a right hemicholectomy. The pathology was compatible with actinic enteritis. The patient after the surgery had a torpid evolution, and finally dies. We describe this case and do a review of all the existent data around the world, because is the first case reported in Peru of an actinic enteritis as a cause of OGIB. PMID:27409093

  15. Unusual presentation of obscure Meckel diverticulum treated with robot-assisted diverticulectomy

    PubMed Central

    Pandey, Sagar; Fan, Miao; Xu, Zhe; Yan, Chaogui; Zhu, Junfeng; Li, Xiuhong

    2016-01-01

    Abstract Introduction: Meckel diverticulum (MD) is the most common congenital abnormality of gastrointestinal tract. Tough believed to occur in 2% of population, most of them remain veiled because majority are clinically asymptomatic and remain obscure in radiological examination. Clinical Findings and Diagnosis: A 26-year-old male with episodic black colored stool since last 10 years. Tough symptomatic, diagnosis of pathological lesion, and the bleeding site could not be established with any of the sophisticated diagnostic technique. After 10 years, it was finally diagnosed as MD with careful observation of bowel loops on computed tomography enterography (CTE) where remnant of vitelline vessel and hyper-enhancing nodule are seen along the wall of diverticular loop. Interventions and outcomes: The patient underwent robot assisted laparoscopic surgery with excision of diverticular loop. To the best of our knowledge, this robot-assistant Meckel diverculectomy is probably the first reported surgical procedure in PubMed. Follow-up for 3 month showed no complication or recurrence. Conclusion: Every case is unique and we must be aware and remain alert in tracing the possible morphological variation of the case. Here, we present one unique but rare feature of MD, which helped us in making diagnosis. PMID:27741148

  16. Obscured AGNs in Bulgeless Hosts discovered by WISE: The Case Study of SDSS J1224+5555

    NASA Astrophysics Data System (ADS)

    Satyapal, S.; Secrest, N. J.; Rothberg, B.; O'Connor, J. A.; Ellison, S. L.; Hickox, R. C.; Constantin, A.; Gliozzi, M.; Rosenberg, J. L.

    2016-08-01

    There is mounting evidence that supermassive black holes (SMBHs) form and grow in bulgeless galaxies. However, a robust determination of the fraction of active galactic nuclei (AGNs) in bulgeless galaxies, an important constraint to models of SMBH seed formation and merger-free models of AGN fueling, is unknown, since optical studies have been shown to be incomplete for AGNs in low-mass galaxies. In a recent study using the Wide-field Infrared Survey Explorer, we discovered hundreds of bulgeless galaxies that display mid-infrared signatures of extremely hot dust suggestive of powerful accreting massive black holes, despite having no signatures of black hole activity at optical wavelengths. Here we report X-ray follow-up observations of J122434.66+555522.3, a nearby (z = 0.052) isolated bulgeless galaxy that contains an unresolved X-ray source detected at the 3σ level by XMM-Newton with an observed luminosity uncorrected for intrinsic absorption of {L}2-10{keV}=(1.1+/- 0.4)× {10}40 erg s-1. Ground-based near-infrared spectroscopy with the Large Binocular Telescope and multiwavelength observations from ultraviolet to millimeter wavelengths together suggest that J1224+5555 harbors a highly absorbed AGN with an intrinsic absorption of {N}{{H}}\\gt {10}24 cm-2. The hard X-ray luminosity of the putative AGN corrected for absorption is {L}2-10{keV}˜ 3× {10}42 erg s-1, which, depending on the bolometric correction factor, corresponds to a bolometric luminosity of the AGN of {L}{bol}.˜ 6× {10}43-3 × 1044 {erg} {{{s}}}-1 and a lower mass limit for the black hole of {M}{BH}≃ 2× {10}6 {M}⊙ , based on the Eddington limit. While enhanced X-ray emission and hot dust can be produced by star formation in extremely low metallicity environments typical in dwarf galaxies, J1224+5555 has a stellar mass of ˜ 2.0× {10}10 {M}⊙ and an above solar metallicity (12 + {logO}/{{H}} = 9.11), typical of our WISE-selected bulgeless galaxy sample. While collectively these

  17. Obscured AGNs in Bulgeless Hosts discovered by WISE: The Case Study of SDSS J1224+5555

    NASA Astrophysics Data System (ADS)

    Satyapal, S.; Secrest, N. J.; Rothberg, B.; O’Connor, J. A.; Ellison, S. L.; Hickox, R. C.; Constantin, A.; Gliozzi, M.; Rosenberg, J. L.

    2016-08-01

    There is mounting evidence that supermassive black holes (SMBHs) form and grow in bulgeless galaxies. However, a robust determination of the fraction of active galactic nuclei (AGNs) in bulgeless galaxies, an important constraint to models of SMBH seed formation and merger-free models of AGN fueling, is unknown, since optical studies have been shown to be incomplete for AGNs in low-mass galaxies. In a recent study using the Wide-field Infrared Survey Explorer, we discovered hundreds of bulgeless galaxies that display mid-infrared signatures of extremely hot dust suggestive of powerful accreting massive black holes, despite having no signatures of black hole activity at optical wavelengths. Here we report X-ray follow-up observations of J122434.66+555522.3, a nearby (z = 0.052) isolated bulgeless galaxy that contains an unresolved X-ray source detected at the 3σ level by XMM-Newton with an observed luminosity uncorrected for intrinsic absorption of {L}2-10{keV}=(1.1+/- 0.4)× {10}40 erg s‑1. Ground-based near-infrared spectroscopy with the Large Binocular Telescope and multiwavelength observations from ultraviolet to millimeter wavelengths together suggest that J1224+5555 harbors a highly absorbed AGN with an intrinsic absorption of {N}{{H}}\\gt {10}24 cm‑2. The hard X-ray luminosity of the putative AGN corrected for absorption is {L}2-10{keV}˜ 3× {10}42 erg s‑1, which, depending on the bolometric correction factor, corresponds to a bolometric luminosity of the AGN of {L}{bol}.˜ 6× {10}43‑3 × 1044 {erg} {{{s}}}-1 and a lower mass limit for the black hole of {M}{BH}≃ 2× {10}6 {M}ȯ , based on the Eddington limit. While enhanced X-ray emission and hot dust can be produced by star formation in extremely low metallicity environments typical in dwarf galaxies, J1224+5555 has a stellar mass of ˜ 2.0× {10}10 {M}ȯ and an above solar metallicity (12 + {logO}/{{H}} = 9.11), typical of our WISE-selected bulgeless galaxy sample. While collectively these

  18. Chasing Personal Meaning: Pedagogical Lessons through Luis Rodriguez's "Always Running"

    ERIC Educational Resources Information Center

    Theisen-Homer, Victoria

    2014-01-01

    In this autobiographical narrative, the author recounts her experiences teaching the novel "Always Running" by Luis Rodriguez with her English classes at a high school in a gang-heavy area. When she first started teaching, this teacher struggled to engage students. One particularly disruptive student requested to read "Always…

  19. Suzaku Observations of Moderately Obscured (Compton-thin) Active Galactic Nuclei Selected by Swift/BAT Hard X-ray Survey

    NASA Astrophysics Data System (ADS)

    Kawamuro, Taiki; Ueda, Yoshihiro; Tazaki, Fumie; Ricci, Claudio; Terashima, Yuichi

    2016-07-01

    We report the results obtained by a systematic, broadband (0.5-150 keV) X-ray spectral analysis of moderately obscured (Compton-thin, 22≤slant {log}{N}{{H}}\\lt 24) active galactic nuclei (AGNs) observed with Suzaku and Swift/Burst Alert Telescope (BAT). Our sample consists of 45 local AGNs at z\\lt 0.1 with {log}{L}14-195{keV}\\gt 42 detected in the Swift/BAT 70-month survey, whose Suzaku archival data are available as of 2015 December. All spectra are uniformly fit with a baseline model composed of an absorbed cutoff power-law component, reflected emission accompanied by a narrow fluorescent iron-Kα line from cold matter (torus), and scattered emission. The main results based on the above analysis are as follows. (1) The photon index is correlated with Eddington ratio, but not with luminosity or black hole mass. (2) The ratio of the luminosity of the iron-Kα line to the X-ray luminosity an indicator of the covering fraction of the torus, shows significant anticorrelation with luminosity. (3) The averaged reflection strength derived from stacked spectra above 14 keV is larger in less luminous ({log}{L}10-50{keV}≤slant 43.3, R={1.04}-0.19+0.17) or highly obscured ({log}{N}{{H}}\\gt 23, R={1.03}-0.17+0.15) AGNs than in more luminous ({log}{L}10-50{keV}\\gt 43.3, R={0.46}-0.09+0.08) or lightly obscured ({log}{N}{{H}}≤slant 23, R={0.59}-0.10+0.09) objects. (4) The ratio of the luminosity of the [{{O}} {{IV}}] 25.89 μm line to the X-ray luminosity is significantly smaller in AGNs with lower soft X-ray scattering fractions, suggesting that the former luminosity underestimates the intrinsic power of an AGN buried in a torus of small opening angle.

  20. Suzaku Observations of Moderately Obscured (Compton-thin) Active Galactic Nuclei Selected by Swift/BAT Hard X-ray Survey

    NASA Astrophysics Data System (ADS)

    Kawamuro, Taiki; Ueda, Yoshihiro; Tazaki, Fumie; Ricci, Claudio; Terashima, Yuichi

    2016-07-01

    We report the results obtained by a systematic, broadband (0.5–150 keV) X-ray spectral analysis of moderately obscured (Compton-thin, 22≤slant {log}{N}{{H}}\\lt 24) active galactic nuclei (AGNs) observed with Suzaku and Swift/Burst Alert Telescope (BAT). Our sample consists of 45 local AGNs at z\\lt 0.1 with {log}{L}14-195{keV}\\gt 42 detected in the Swift/BAT 70-month survey, whose Suzaku archival data are available as of 2015 December. All spectra are uniformly fit with a baseline model composed of an absorbed cutoff power-law component, reflected emission accompanied by a narrow fluorescent iron-Kα line from cold matter (torus), and scattered emission. The main results based on the above analysis are as follows. (1) The photon index is correlated with Eddington ratio, but not with luminosity or black hole mass. (2) The ratio of the luminosity of the iron-Kα line to the X-ray luminosity an indicator of the covering fraction of the torus, shows significant anticorrelation with luminosity. (3) The averaged reflection strength derived from stacked spectra above 14 keV is larger in less luminous ({log}{L}10-50{keV}≤slant 43.3, R={1.04}-0.19+0.17) or highly obscured ({log}{N}{{H}}\\gt 23, R={1.03}-0.17+0.15) AGNs than in more luminous ({log}{L}10-50{keV}\\gt 43.3, R={0.46}-0.09+0.08) or lightly obscured ({log}{N}{{H}}≤slant 23, R={0.59}-0.10+0.09) objects. (4) The ratio of the luminosity of the [{{O}} {{IV}}] 25.89 μm line to the X-ray luminosity is significantly smaller in AGNs with lower soft X-ray scattering fractions, suggesting that the former luminosity underestimates the intrinsic power of an AGN buried in a torus of small opening angle.

  1. Smoke and obscurants; a health and environmental effects data base assessment. A first-order, environmental screening and ranking of Army smokes and obscurants. Report for 1983-1985 on Phase 1

    SciTech Connect

    Shinn, J.H.; Martins, S.A.; Cedarwall, P.L.; Gratt, L.B.

    1985-02-01

    An initial environmental screening and ranking is provided for each Army smoke and obscurant depending on smoke type and smoke-generating device. This was done according to the magnitude of the impact area, the characteristic environmental concentration, the relative inhalation toxicity, the relative toxicity when ingested concentration, the relative inhalation toxicity, the relative toxicity when ingested by animals, the aquatic toxicity, the environmental mobility when freshly deposited, and the ultimate mobility and fate in the environment. The major smoke types considered were various forms of white phosphorus, red phosphorus, hexachlorethane-derived smokes (HC), fog-oil (SGF-2), diesel fuel smokes (DF), and some infrared obscuring agents. The results were ranked according to: Device Impact Area and Environmental Concentration; Inhalation Toxicity and Air Concentration Quotient; Oral Toxicity and Ingestion Quotient; Aquatic Toxicity Quotient; Short-Term and Long-Term Mobility in the Environment; and Overall Environmental Importance.

  2. Stellar and quasar feedback in concert: effects on AGN accretion, obscuration, and outflows

    NASA Astrophysics Data System (ADS)

    Hopkins, Philip F.; Torrey, Paul; Faucher-Giguère, Claude-André; Quataert, Eliot; Murray, Norman

    2016-05-01

    We study the interaction of feedback from active galactic nuclei (AGN) and a multiphase interstellar medium (ISM), in simulations including explicit stellar feedback, multiphase cooling, accretion-disc winds, and Compton heating. We examine radii ˜0.1-100 pc around a black hole (BH), where the accretion rate on to the BH is determined and where AGN-powered winds and radiation couple to the ISM. We conclude: (1) the BH accretion rate is determined by exchange of angular momentum between gas and stars in gravitational instabilities. This produces accretion rates ˜0.03-1 M⊙ yr-1, sufficient to power luminous AGN. (2) The gas disc in the galactic nucleus undergoes an initial burst of star formation followed by several million years where stellar feedback suppresses the star formation rate (SFR). (3) AGN winds injected at small radii with momentum fluxes ˜LAGN/c couple efficiently to the ISM and have dramatic effects on ISM properties within ˜100 pc. AGN winds suppress the nuclear SFR by factors ˜10-30 and BH accretion rate by factors ˜3-30. They increase the outflow rate from the nucleus by factors ˜10, consistent with observational evidence for galaxy-scale AGN-driven outflows. (4) With AGN feedback, the predicted column density distribution to the BH is consistent with observations. Absent AGN feedback, the BH is isotropically obscured and there are not enough optically thin sightlines to explain type-I AGN. A `torus-like' geometry arises self-consistently as AGN feedback evacuates gas in polar regions.

  3. Star Formation and Dust Obscuration at z ≈ 2: Galaxies at the Dawn of Downsizing

    NASA Astrophysics Data System (ADS)

    Pannella, M.; Carilli, C. L.; Daddi, E.; McCracken, H. J.; Owen, F. N.; Renzini, A.; Strazzullo, V.; Civano, F.; Koekemoer, A. M.; Schinnerer, E.; Scoville, N.; Smolčić, V.; Taniguchi, Y.; Aussel, H.; Kneib, J. P.; Ilbert, O.; Mellier, Y.; Salvato, M.; Thompson, D.; Willott, C. J.

    2009-06-01

    We present first results of a study aimed to constrain the star formation rate (SFR) and dust content of galaxies at z ≈ 2. We use a sample of BzK-selected star-forming galaxies, drawn from the Cosmic Evolution Survey, to perform a stacking analysis of their 1.4 GHz radio continuum as a function of different stellar population properties, after cleaning the sample from contamination by active galactic nuclei. Dust unbiased SFRs are derived from radio fluxes assuming the local radio-IR correlation. The main results of this work are: (1) specific star formation rate (SSFR)s are constant over about 1 dex in stellar mass and up to the highest stellar mass probed, (2) the dust attenuation is a strong function of galaxy stellar mass with more massive galaxies being more obscured than lower mass objects, (3) a single value of the UV extinction applied to all galaxies would lead to a gross underestimate of the SFR in massive galaxies, (4) correcting the observed UV luminosities for dust attenuation based on the Calzetti recipe provides results in very good agreement with the radio derived ones, (5) the mean SSFR of our sample steadily decreases by a factor of ~4 with decreasing redshift from z = 2.3 to 1.4 and a factor of ~40 down the local universe. These empirical SFRs would cause galaxies to dramatically overgrow in mass if maintained all the way to low redshifts; we suggest that this does not happen because star formation is progressively quenched, likely starting from the most massive galaxies. Based on observations collected, within the COSMOS Legacy Survey, at the HST, Chandra, XMM, Keck, NRAO-VLA, Subaru, KPNO, CTIO, CFHT, and ESO observatories. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  4. Seafood substitutions obscure patterns of mercury contamination in Patagonian toothfish (Dissostichus eleginoides) or "Chilean sea bass".

    PubMed

    Marko, Peter B; Nance, Holly A; van den Hurk, Peter

    2014-01-01

    Seafood mislabeling distorts the true abundance of fish in the sea, defrauds consumers, and can also cause unwanted exposure to harmful pollutants. By combining genetic data with analyses of total mercury content, we have investigated how species substitutions and fishery-stock substitutions obscure mercury contamination in Patagonian toothfish (Dissostichus eleginoides), also known as "Chilean sea bass". Patagonian toothfish show wide variation in mercury concentrations such that consumers may be exposed to either acceptable or unacceptable levels of mercury depending on the geographic origins of the fish and the allowable limits of different countries. Most notably, stocks of Patagonian toothfish in Chile accumulate significantly more mercury than stocks closer to the South Pole, including the South Georgia/Shag Rocks stock, a fishery certified by the Marine Stewardship Council (MSC) as sustainably fished. Consistent with the documented geography of mercury contamination, our analysis showed that, on average, retail fish labeled as MSC-certified Patagonian toothfish had only half the mercury of uncertified fish. However, consideration of genetic data that were informative about seafood substitutions revealed a complex pattern of contamination hidden from consumers: species substitutions artificially inflated the expected difference in mercury levels between MSC-certified and uncertified fish whereas fishery stock substitutions artificially reduced the expected difference in mercury content between MSC-certified and uncertified fish that were actually D. eleginoides. Among MSC-certified fish that were actually D. eleginoides, several with exogenous mtDNA haplotypes (i.e., not known from the certified fishery) had mercury concentrations on par with uncertified fish from Chile. Overall, our analysis of mercury was consistent with inferences from the genetic data about the geographic origins of the fish, demonstrated the potential negative impact of seafood

  5. Radiation obscuration by dust devils at Gale as observed by the REMS UV Sensor

    NASA Astrophysics Data System (ADS)

    Zorzano, María-Paz; Martín-Torres, Francisco Javier; Kahanpää, Henrik; Moore, John; Navarro, Sara; Lepinette, Alain; Sebastian, Eduardo; Gómez-Elvira, Javier; REMS Team; MSL Science Team

    2013-04-01

    The Rover Environmental Monitoring Station (REMS) on board the Curiosity rover has been exploring the surface environment of Mars since its arrival to Gale on August 2012. REMS provides a mimimum of 5 minutes of acquisitions every hour and extended 1-hour acquisitions of all its sensors, namely wind, air temperature, ground temperature, pressure, humidity and ultraviolet sensors. The UV sensor (UVS) of REMS is dedicated to monitoring the downwelling UV irradiance as well as to monitor the atmospheric dust cycle of Mars. This includes observation of plausible dust loading processes such as dust devils. A dust devil is a convective vortex that rises dust in a whirlwind structure. The base of the dust devil moves with a certain speed and its column of dust may traverse the path of observation of the Sun. Usually when this happens a sudden drop of the UV signature is observed. In other cases a plume rises dust and changes the UV diffuse irradiance profile. Since the beginning of REMS operations in Mars, a number of processes have left signatures on the UV direct or diffuse irradiance as observed by the REMS UV sensor. The signatures of some specific examples are analyzed and compared with the observations provided by other REMS sensors. These are the first measurements of its kind of a dust devil in Mars and provide estimates of the UV opacity of these structures and of their scale. When an obscuration is observed the decay of each specific channel can used to evaluate the spectral variation of the irradiance. This kind of studies may be extremelly interesting to compare with visible opacities of dust devils as observed by the MSL cameras. The regular acquisition pattern of REMS will allow to estimate sistematically the opacity of these structures during the two years of nominal operation from the Martian surface.

  6. Search for Hyperluminous Infrared Dust-obscured Galaxies Selected with WISE and SDSS

    NASA Astrophysics Data System (ADS)

    Toba, Y.; Nagao, T.

    2016-03-01

    We aim to search for hyperluminous infrared (IR) galaxies (HyLIRGs) with IR luminosity {L}{{IR}} > 1013 L⊙ by applying the selection method of dust-obscured galaxies (DOGs). They are spatially rare but could correspond to a maximum phase of cosmic star formation (SF) and/or active galactic nucleus (AGN) activity hence, they are a crucial population for understanding the SF and mass assembly history of galaxies. Combining the optical and IR catalogs obtained from the Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer (WISE), we performed the extensive HyLIRGs survey; we selected 5311 IR-bright DOGs with i - [22] > 7.0 and flux at 22 μm > 3.8 mJy in 14,555 deg2, where i and [22] are i-band and 22 μm AB magnitudes, respectively. Among them, 67 DOGs have reliable spectroscopic redshifts that enable us to estimate their total IR luminosity based on the spectral energy distribution fitting. Consequently, we successfully discovered 24 HyLIRGs among the 67 spectroscopically confirmed DOGs. We found that (i) i - [22] color of IR-bright DOGs correlates with the total IR luminosity and (ii) the surface number density of HyLIRGs is >0.17 deg-2. A large fraction (˜73%) of IR-bright DOGs with i - [22] > 7.5 show {L}{{IR}} > 1013 L⊙, and the DOG criterion we adopted could be independently effective against the “W1W2-dropout method,” based on four WISE bands, for searching hyperluminous IR populations of galaxies.

  7. A differential game solution to the Coplanar tail-chase aerial combat problem

    NASA Technical Reports Server (NTRS)

    Merz, A. W.; Hague, D. S.

    1976-01-01

    Numerical results obtained in a simplified version of the one on one aerial combat problem are presented. The primary aim of the data is to specify the roles of pursuer and evader as functions of the relative geometry and of the significant physical parameters of the problem. Numerical results are given in a case in which the slower aircraft is more maneuverable than the faster aircraft. A third order dynamic model of the relative motion is described, for which the state variables are relative range, bearing, and heading. The ranges at termination are arbitary in the present version of the problem, so the weapon systems of both aircraft can be visualized as forward firing high velocity weapons, which must be aimed at the tail pipe of the evader. It was found that, for the great majority of the ralative geometries, each aircraft can evade the weapon system of the other.

  8. Survey and Chase: A New Method of Observations For The Michigan Orbital Debris Survey Telescope (MODEST)

    NASA Technical Reports Server (NTRS)

    Abercromby, Kira J.; Seitzer, Patrick; Rodriquez, Heather M.; Barker, Edwin S.; Matney, Mark J.

    2006-01-01

    For more than 40 years astronauts have been observing Earth, taking photographs or digital images from their spacecraft. Today, a robust program of observation from the International Space Station (ISS) has yielded hundreds of thousands of images of the Earth s surface collected since 2001. Seeing Earth through the eyes of an astronaut is exciting to the general public, and the images are popular in classrooms. Because the ISS has an orbital inclination of 51.6 degrees (the north-south limits of the orbit are at 51.6 degrees latitude), high latitude observations are common. Some of the most striking images collected include views of polar phenomena. Astronauts routinely pass above brilliant red and green aurora; view high, wispy clouds at the top of the atmosphere; or look down on glaciers and floating ice rafts. These images, framed and captured by humans, are easily interpreted by students and teachers. Astronaut observations provide a way to visualize complicated polar phenomena and communicate about them to students of all ages. Over the next two years, astronauts aboard the ISS will formally focus their observations on polar phenomena as participants in the International Polar Year (IPY). Imagery acquisition from the ISS will be coordinated with other IPY scientists staging studies and field campaigns on the ground. The imagery collected from the ISS will be cataloged and served on NASA s web-based database of images, http://eol.jsc.nasa.gov . The website allows investigators, students and teachers to search through the imagery, assemble image datasets, and download the imagery and the metadata. We display some of the most spectacular examples of polar imagery and demonstrate NASA s database of astronaut images of Earth.

  9. X-RAY AND NEAR-INFRARED OBSERVATIONS OF THE OBSCURED ACCRETING PULSAR IGR J18179-1621

    SciTech Connect

    Nowak, M. A.; Paizis, A.; Rodriguez, J.; Chaty, S.; Grinberg, V.; Wilms, J.; Chini, R. E-mail: ada@iasf-milano.inaf.it

    2012-10-01

    IGR J18179-1621 is an obscured accreting X-ray pulsar discovered by INTEGRAL on 2012 February 29. We report on our 20 ks Chandra-High Energy Transmission Gratings Spectrometer observation of the source performed on 2012 March 17, on two short contemporaneous Swift observations, and on our two near-infrared (K{sub s} , H{sub n} , and J{sub n} ) observations performed on 2012 March 13 and 26. We determine the most accurate X-ray position of IGR J18179-1621, {alpha}{sub J2000} = 18{sup h}17{sup m}52.{sup s}18, {delta}{sub J2000} = -16 Degree-Sign 21'31.''68 (90% uncertainty of 0.''6). A strong periodic variability at 11.82 s is clearly detected in the Chandra data, confirming the pulsating nature of the source, with the light-curve softening at the pulse peak. The quasi-simultaneous Chandra-Swift spectra of IGR J18179-1621 can be well fit by a heavily absorbed hard power law (N{sub H} = 2.2 {+-} 0.3 Multiplication-Sign 10{sup 23} cm{sup -2} and photon index {Gamma} = 0.4 {+-} 0.1) with an average absorbed 2-8 keV flux of 1.4 Multiplication-Sign 10{sup -11} erg cm{sup -2} s{sup -1}. At the Chandra-based position, a source is detected in our near-infrared (NIR) maps with K{sub s} 13.14 {+-} 0.04 mag, H{sub n} = 16 {+-} 0.1 mag, and no J{sub n} -band counterpart down to {approx}18 mag. The NIR source, compatible with 2MASS J18175218-1621316, shows no variability between 2012 March 13 and 26. Searches of the UKIDSS database show similar NIR flux levels at epochs six months prior to and after a 2007 February 11 archival Chandra observation where the source's X-ray flux was at least 87 times fainter. In many ways IGR J18179-1621 is unusual: its combination of a several week long outburst (without evidence of repeated outbursts in the historical record), high absorption column (a large fraction of which is likely local to the system), and 11.82 s period does not fit neatly into existing X-ray binary categories.

  10. AGN - Dust-Obscured Galaxies at z~1-3 revealed by near-to-far infrared SED-fitting

    NASA Astrophysics Data System (ADS)

    Riguccini, Laurie

    Dust-Obscured galaxies (DOGs, Dey et al. 2008) are bright 24μm-selected sources with extreme obscuration at optical wavelengths (F24μ m /F R > 982). Recent studies (Dey et al. 2008, Bussmann et al. 2009) describe an evolutionary scenario in which the starbursting nature of submillimeter galaxies (SMGs) evolves into the composite nature of DOGs as an underlying AGN grows; this is followed by a quasar phase that terminates star formation (SF), leading to the formation of a passive, massive elliptical galaxy. Within this context, DOGs could provide a key insight to an extremely dusty stage in the evolution of galaxies at z ~ 2, where both AGN and SF activity coexist.

  11. ALMA observations of the host galaxy of GRB 090423 at z = 8.23: deep limits on obscured star formation 630 million years after the big bang

    SciTech Connect

    Berger, E.; Zauderer, B. A.; Chary, R.-R.; Laskar, T.; Chornock, R.; Davies, J. E.; Tanvir, N. R.; Stanway, E. R.; Levan, A. J.; Levesque, E. M.

    2014-12-01

    We present rest-frame far-infrared (FIR) and optical observations of the host galaxy of GRB 090423 at z = 8.23 from the Atacama Large Millimeter Array (ALMA) and the Spitzer Space Telescope, respectively. The host remains undetected to 3σ limits of F {sub ν}(222 GHz) ≲ 33 μJy and F {sub ν}(3.6 μm) ≲ 81 nJy. The FIR limit is about 20 times fainter than the luminosity of the local ULIRG Arp 220 and comparable to the local starburst M 82. Comparing this with model spectral energy distributions, we place a limit on the infrared (IR) luminosity of L {sub IR}(8-1000 μm) ≲ 3 × 10{sup 10} L {sub ☉}, corresponding to a limit on the obscured star formation rate of SFR{sub IR}≲5 M {sub ☉} yr{sup –1}. For comparison, the limit on the unobscured star formation rate from Hubble Space Telescope rest-frame ultraviolet (UV) observations is SFR{sub UV} ≲ 1 M {sub ☉} yr{sup –1}. We also place a limit on the host galaxy stellar mass of M {sub *} ≲ 5 × 10{sup 7} M {sub ☉} (for a stellar population age of 100 Myr and constant star formation rate). Finally, we compare our millimeter observations to those of field galaxies at z ≳ 4 (Lyman break galaxies, Lyα emitters, and submillimeter galaxies) and find that our limit on the FIR luminosity is the most constraining to date, although the field galaxies have much larger rest-frame UV/optical luminosities than the host of GRB 090423 by virtue of their selection techniques. We conclude that GRB host galaxies at z ≳ 4, especially those with measured interstellar medium metallicities from afterglow spectroscopy, are an attractive sample for future ALMA studies of high redshift obscured star formation.

  12. Chasing the association of single-pulse gamma-ray bursts and supernovae

    NASA Astrophysics Data System (ADS)

    Bonnell, J.; Norris, J.; Watanabe, K.

    1999-09-01

    We explore the hypothesis, similar to one recently suggested by Bloom and colleagues, that some nearby supernovae are associated with smooth, single-pulse gamma-ray bursts, possibly having no emission above 300 keV. We examine BATSE bursts with durations longer than 2 s, fitting those which can be visually characterized as single-pulse events with a lognormal pulse model. The fraction of events that can be reliably ascertained to be temporally and spectrally similar to the exemplar, GRB 980425 - possibly associated with SN 1998bw - is 4/1573 or 0.25%. This fraction could be as high as 8/1573 (0.5%) if the dimmest bursts are included. Approximately 2% of bursts are morphologically similar to GRB 980425 but have emission above 300 keV. A search of supernova catalogs containing 630 detections during BATSE's lifetime reveals only one burst (GRB 980425) within a 3-month time window and within the total 3 sigma BATSE error radius that could be associated with a type Ib/c supernova. Thus we find no further evidence to support a single-pulse GRB and SN Ib/c connection. We also find no tendency for any set of single-pulse GRBs to fall near the Supergalactic Plane, whereas SNe of type Ib/c do show this tendency - evidence that the two phenomena are not related.

  13. Tracking GPCR biosynthesis and degradation using a nonradioactive pulse chase methodology.

    PubMed

    Wargachuk, Richard; Devost, Dominic; Zhou, Cynthia; Hébert, Terence E

    2016-01-01

    The β2-adrenergic receptor (β2AR) is a prototypical member of the G protein-coupled receptor (GPCR) superfamily of proteins and is one of the best-characterized GPCRs due to its role in several important physiological systems. Because of limited availability of high quality antibodies against GPCRs, much of the work done on β2AR took advantage of heterologous expression systems. Overexpressed proteins may overwhelm the cellular regulatory machinery leading potentially to responses distinct from the native protein. To address this issue we generated a stable cell line with a tetracycline-inducible β2AR tagged with a FLAG epitope, such that we are able to control the quantity of receptor produced. This allows us to induce a discrete pulse of FLAG-β2AR transcription and translation allowing us to follow the complete life cycle of the protein from synthesis as an immature protein to degradation. We show that such limited pulses of receptor expression lead to signaling phenotypes that more closely reflect endogenous signaling events.

  14. Chasing Nonexistent Compounds with Lasers: Electronic Spectroscopy of Main Group Transient Molecules, Free Radicals, and Ions

    NASA Astrophysics Data System (ADS)

    Clouthier, Dennis J.

    2011-06-01

    One of the important contributions of the science of high resolution molecular spectroscopy has been the identification and characterization of new molecules in the gas phase, whether they exist in the laboratory, in extreme terrestrial environments, or in outer space. Despite the innovative efforts of many dedicated spectroscopists, one can still easily visualize a large number of novel small molecules that remain to be discovered and investigated. In this talk I will review the efforts of our group in recent years to study the electronic spectra of some new, and some not so new but still challenging species, concentrating primarily on those that are made up of main group elements. The target molecules have been produced in a pulsed electric discharge at the exit of a supersonic jet, often using novel precursors which we have had to synthesize in the laboratory. Conventional laser-induced fluorescence as well as wavelength resolved emission, stimulated emission pumping, fluorescence depletion and LIF sync-scan techniques have been used to detect the species of interest. Examples of diatomic and polyatomic transient molecules, free radicals, and ions that we have recently explored will be discussed.

  15. NUSTAR Unveils a Heavily Obscured Low-luminosity Active Galactic Nucleus in the Luminous Infrared Galaxy NGC 6286

    NASA Astrophysics Data System (ADS)

    Ricci, C.; Bauer, F. E.; Treister, E.; Romero-Cañizales, C.; Arevalo, P.; Iwasawa, K.; Privon, G. C.; Sanders, D. B.; Schawinski, K.; Stern, D.; Imanishi, M.

    2016-03-01

    We report the detection of a heavily obscured active galactic nucleus (AGN) in the luminous infrared galaxy (LIRG) NGC 6286 identified in a 17.5 ks Nuclear Spectroscopic Telescope Array observation. The source is in an early merging stage and was targeted as part of our ongoing NuSTAR campaign observing local luminous and ultra-luminous infrared galaxies in different merger stages. NGC 6286 is clearly detected above 10 keV and by including the quasi-simultaneous Swift/XRT and archival XMM-Newton and Chandra data, we find that the source is heavily obscured (NH ≃(0.95-1.32) × 1024 cm-2) with a column density consistent with being Compton-thick (CT, {log}({N}{{H}}/{{cm}}-2)≥slant 24). The AGN in NGC 6286 has a low absorption-corrected luminosity (L2-10 keV ˜ 3-20 × 1041 erg s-1) and contributes ≲1% to the energetics of the system. Because of its low luminosity, previous observations carried out in the soft X-ray band (<10 keV) and in the infrared did not notice the presence of a buried AGN. NGC 6286 has multiwavelength characteristics typical of objects with the same infrared luminosity and in the same merger stage, which might imply that there is a significant population of obscured low-luminosity AGNs in LIRGs that can only be detected by sensitive hard X-ray observations.

  16. Chasing Ghosts in Space Radiobiology Research: The Lost Focus on Non-Targeted Effects

    NASA Astrophysics Data System (ADS)

    Cucinotta, Francis; Saganti, Premkumar; Cacao, Eliedonna

    2016-07-01

    The doses and dose-rates of astronaut exposures to galactic cosmic rays (GCR) are accurately known, and lead to particle hits per cell nucleus from high charge and energy (HZE) particles of much less than one hit per cell per week. A large number of experiments have shown that additivity of biological effects is a valid assumption for space radiation exposures, while experiments at higher doses and dose-rates than occur in space continue to be a focus of the majority of space radiobiology research. Furthermore HZE particle exposures with mono-energetic particles manifest themselves as a mixed-radiation field due to the contributions of delta-rays and the random impact parameter of a particles track core to DNA and non-DNA targets in cells and tissues. The mixed-field manifestation of mono-energetic HZE particle exposures is well known from theoretical studies of microdosimetry and track structure. Additional mixed-field effects occur for single species experiments due to nuclear fragmentation in particle accelerator beam-lines and biological samples along with energy straggling. In contrast to these well known aspects of space radiobiology there are many open questions on the contribution of non-targeted effects to low dose and dose-rate exposures. Non-targeted effects (NTEs) include bystander effects and genomic instability, and have been shown to be the most important outstanding question for reducing uncertainties in space radiation cancer risk assessment. The dose-rate and radiation quality dependence of NTE's has not been established, while there is an over-arching need to develop 21st century experimental models of human cancer risk. We review possible mechanisms of NTE's and how new experiments to address these issues could be designed.

  17. Chasing Phosphoarginine Proteins: Development of a Selective Enrichment Method Using a Phosphatase Trap*

    PubMed Central

    Trentini, Débora Broch; Fuhrmann, Jakob; Mechtler, Karl; Clausen, Tim

    2014-01-01

    Arginine phosphorylation is an emerging post-translational protein modification implicated in the bacterial stress response. Although early reports suggested that arginine phosphorylation also occurs in higher eukaryotes, its overall prevalence was never studied using modern mass spectrometry methods, owing to technical difficulties arising from the acid lability of phosphoarginine. As shown recently, the McsB and YwlE proteins from Bacillus subtilis function as a highly specific protein arginine kinase and phosphatase couple, shaping the phosphoarginine proteome. Using a B. subtilis ΔywlE strain as a source for arginine-phosphorylated proteins, we were able to adapt mass spectrometry (MS) protocols to the special chemical properties of the arginine modification. Despite this progress, the analysis of protein arginine phosphorylation in eukaryotes is still challenging, given the great abundance of serine/threonine phosphorylations that would compete with phosphoarginine during the phosphopeptide enrichment procedure, as well as during data-dependent MS acquisition. We thus set out to establish a method for the selective enrichment of arginine-phosphorylated proteins as an initial step in the phosphoproteomic analysis. For this purpose, we developed a substrate-trapping mutant of the YwlE phosphatase that retains binding affinity toward arginine-phosphorylated proteins but cannot hydrolyze the captured substrates. By testing a number of active site substitutions, we identified a YwlE mutant (C9A) that stably binds to arginine-phosphorylated proteins. We further improved the substrate-trapping efficiency by impeding the oligomerization of the phosphatase mutant. The engineered YwlE trap efficiently captured arginine-phosphorylated proteins from complex B. subtilis ΔywlE cell extracts, thus facilitating identification of phosphoarginine sites in the large pool of cellular protein modifications. In conclusion, we present a novel tool for the selective enrichment and

  18. A REDSHIFT SURVEY OF HERSCHEL FAR-INFRARED SELECTED STARBURSTS AND IMPLICATIONS FOR OBSCURED STAR FORMATION

    SciTech Connect

    Casey, C. M.; Budynkiewicz, J.; Berta, S.; Lutz, D.; Magnelli, B.; Bethermin, M.; Le Floc'h, E.; Magdis, G.; Burgarella, D.; Chapin, E.; Chapman, S. C.; Clements, D. L.; Conley, A.; Conselice, C. J.; Cooray, A.; Farrah, D.; Hatziminaoglou, E.; Ivison, R. J.; and others

    2012-12-20

    We present Keck spectroscopic observations and redshifts for a sample of 767 Herschel-SPIRE selected galaxies (HSGs) at 250, 350, and 500 {mu}m, taken with the Keck I Low Resolution Imaging Spectrometer and the Keck II DEep Imaging Multi-Object Spectrograph. The redshift distribution of these SPIRE sources from the Herschel Multitiered Extragalactic Survey peaks at z = 0.85, with 731 sources at z < 2 and a tail of sources out to z {approx} 5. We measure more significant disagreement between photometric and spectroscopic redshifts (({Delta}z/(1 + z{sub spec})) = 0.29) than is seen in non-infrared selected samples, likely due to enhanced star formation rates and dust obscuration in infrared-selected galaxies. The infrared data are used to directly measure integrated infrared luminosities and dust temperatures independent of radio or 24 {mu}m flux densities. By probing the dust spectral energy distribution (SED) at its peak, we estimate that the vast majority (72%-83%) of z < 2 Herschel-selected galaxies would drop out of traditional submillimeter surveys at 0.85-1 mm. We find that dust temperature traces infrared luminosity, due in part to the SPIRE wavelength selection biases, and partially from physical effects. As a result, we measure no significant trend in SPIRE color with redshift; if dust temperature were independent of luminosity or redshift, a trend in SPIRE color would be expected. Composite infrared SEDs are constructed as a function of infrared luminosity, showing the increase in dust temperature with luminosity, and subtle change in near-infrared and mid-infrared spectral properties. Moderate evolution in the far-infrared (FIR)/radio correlation is measured for this partially radio-selected sample, with q{sub IR}{proportional_to}(1 + z){sup -0.30{+-}0.02} at z < 2. We estimate the luminosity function and implied star formation rate density contribution of HSGs at z < 1.6 and find overall agreement with work based on 24 {mu}m extrapolations of the LIRG

  19. New methods for reducing cloud obscuration based on combination products of MODIS and AMSR2

    NASA Astrophysics Data System (ADS)

    Li, Muyi; Pan, Yaozhong; Zhu, Xiufang; Yin, Heyang

    2016-04-01

    As one of the main sources for water availability in semi-arid mountain regions, snow melt provides runoff and water supply for the downstream population and is of great importance for both human and environmental systems. For this reason, snow data such as snow cover (SCA) and snow depth (SD) is especially important. Snow cover has been mapped using many remote sensors in the visible, near-infrared, thermal, and microwave wavelengths. Since 1966, optical remote sensors such as AVHRR, Landsat and MODIS have obtained critically important data for observing the earth's snow cover. The Moderate Resolution Imaging Spectroradiometer (MODIS) employed by Terra and Aqua satellites provides spatially snow covered data with 500 m and daily temporal resolution. However the utility of the MODIS snow-cover products is limited by cloud cover which causes gaps in the daily snow-cover map products. In this paper, we developed a new method in order to reduce cloud obscuration. This method includes four parts: A) Combining various MODIS Terra and Aqua products; B) Temporal and spatial filtering; C) Zonal snowline approach and D) Combining the product deriving from the above three parts and the AMSR2 passive microwave snow depth product (with a spatial resolution of 10 km). In part D, the consistency of two different data (optical remote sensing data with spatial resolution of 500 m and passive microwave remote sensing data with a spatial resolution of 10 km) was evaluated. This study was carried out for Qinghai Province located in northwestern part of China during 1st, October, 2013 to 31st, March, 2015. In order to evaluate the performance of the proposed methodology, 14 MODIS snow cover product tiles (with cloud coverage less than 10%) were selected as possible "ground truth" data and cloud mask was generated for each tile randomly. The results show successful performances arising from the methods applied, which resulted in all cloud coverage being removed. The overall accuracy of

  20. The Nature of Faint Spitzer-selected Dust-obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Pope, Alexandra; Bussmann, R. Shane; Dey, Arjun; Meger, Nicole; Alexander, David M.; Brodwin, Mark; Chary, Ranga-Ram; Dickinson, Mark E.; Frayer, David T.; Greve, Thomas R.; Huynh, Minh; Lin, Lihwai; Morrison, Glenn; Scott, Douglas; Yan, Chi-Hung

    2008-12-01

    We use deep far-IR, submillimeter, radio, and X-ray imaging and mid-IR spectroscopy to explore the nature of a sample of Spitzer-selected dust-obscured galaxies (DOGs) in GOODS-N. A sample of 79 galaxies satisfy the criteria R - [ 24] > 14 (Vega) down to S24 > 100 μJy (median flux density S24 = 180 μJy). Twelve of these galaxies have IRS spectra available, which we use to measure redshifts and classify these objects as being dominated by star formation or active galactic nucleus (AGN) activity in the mid-IR. The IRS spectra and Spitzer photometric redshifts confirm that the DOGs lie in a tight redshift distribution around z ~ 2. Based on mid-IR colors, 80% of DOGs are likely dominated by star formation; the stacked X-ray emission from this subsample of DOGs is also consistent with star formation. Since only a small number of DOGs are individually detected at far-IR and submillimeter wavelengths, we use a stacking analysis to determine the average flux from these objects and plot a composite IR (8-1000 μm) spectral energy distribution (SED). The average luminosity of these star-forming DOGs is LIR ~ 1 × 1012 L⊙. We compare the average star-forming DOG to the average bright (S850 > 5 mJy) submillimeter galaxy (SMG); the S24 > 100 μJy DOGs are 3 times more numerous but 8 times less luminous in the IR. The far-IR SED shape of DOGs is similar to that of SMGs (average dust temperature of around 30 K), but DOGs have a higher mid-IR-to-far-IR flux ratio. The average star formation-dominated DOG has a star formation rate of 200 M⊙ yr -1, which, given their space density, amounts to a contribution of 0.01 M⊙ yr-1 Mpc-3 (or 5%-10%) to the star formation rate density at z ~ 2.

  1. Capsule Endoscopy in the Assessment of Obscure Gastrointestinal Bleeding: An Economic Analysis

    PubMed Central

    Palimaka, S; Blackhouse, Gord; Goeree, Ron

    2015-01-01

    Background Small-bowel capsule endoscopy is a tool used to visualize the small bowel to identify the location of bleeds in obscure gastrointestinal bleeding (OGIB). Capsule endoscopy is currently funded in Ontario in cases where there has been a failure to identify a source of bleeding via conventional diagnostic procedures. In Ontario, capsule endoscopy is a diagnostic option for patients whose findings on esophagogastroduodenoscopy, colonoscopy, and push enteroscopy have been negative (i.e., the source of bleeding was not found). Objectives This economic analysis aims to estimate the budget impact of different rates of capsule endoscopy use as a complement to push enteroscopy procedures in patients aged 18 years and older. Data Sources Population-based administrative databases for Ontario were used to identify patients receiving push enteroscopy and small-bowel capsule endoscopy in the fiscal years 2008 to 2012. Review Methods A systematic literature search was performed to identify economic evaluations of capsule endoscopy for the investigation of OGIB. Studies were assessed for their methodological quality and their applicability to the Ontarian setting. An original budget impact analysis was performed using data from Ontarian administrative sources and published literature. The budget impact was estimated for different levels of use of capsule endoscopy as a complement to push enteroscopy due to the uncertain clinical utility of the capsule based on current clinical evidence. The analysis was conducted from the provincial public payer perspective. Results With varying rates of capsule endoscopy use, the budgetary impact spans from savings of $510,000,1 when no (0%) push enteroscopy procedures are complemented with capsule endoscopy, to $2,036,000, when all (100%) push enteroscopy procedures are complemented with capsule endoscopy. A scenario where 50% of push enteroscopy procedures are complemented with capsule endoscopy (expected use based on expert opinion

  2. Robust forecasts on fundamental physics from the foreground-obscured, gravitationally-lensed CMB polarization

    NASA Astrophysics Data System (ADS)

    Errard, Josquin; Feeney, Stephen M.; Peiris, Hiranya V.; Jaffe, Andrew H.

    2016-03-01

    Recent results from the BICEP, Keck Array and Planck Collaborations demonstrate that Galactic foregrounds are an unavoidable obstacle in the search for evidence of inflationary gravitational waves in the cosmic microwave background (CMB) polarization. Beyond the foregrounds, the effect of lensing by intervening large-scale structure further obscures all but the strongest inflationary signals permitted by current data. With a plethora of ongoing and upcoming experiments aiming to measure these signatures, careful and self-consistent consideration of experiments' foreground- and lensing-removal capabilities is critical in obtaining credible forecasts of their performance. We investigate the capabilities of instruments such as Advanced ACTPol, BICEP3 and Keck Array, CLASS, EBEX10K, PIPER, Simons Array, SPT-3G and SPIDER, and projects as COrE+, LiteBIRD-ext, PIXIE and Stage IV, to clean contamination due to polarized synchrotron and dust from raw multi-frequency data, and remove lensing from the resulting co-added CMB maps (either using iterative CMB-only techniques or through cross-correlation with external data). Incorporating these effects, we present forecasts for the constraining power of these experiments in terms of inflationary physics, the neutrino sector, and dark energy parameters. Made publicly available through an online interface, this tool enables the next generation of CMB experiments to foreground-proof their designs, optimize their frequency coverage to maximize scientific output, and determine where cross-experimental collaboration would be most beneficial. We find that analyzing data from ground, balloon and space instruments in complementary combinations can significantly improve component separation performance, delensing, and cosmological constraints over individual datasets. In particular, we find that a combination of post-2020 ground- and space-based experiments could achieve constraints such as σ(r)~1.3×10-4, σ(nt)~0.03, σ( ns )~1.8×10

  3. Capsule Endoscopy in the Assessment of Obscure Gastrointestinal Bleeding: An Evidence-Based Analysis

    PubMed Central

    2015-01-01

    Background Obscure gastrointestinal bleeding (OGIB) is defined as persistent or recurrent bleeding associated with negative findings on upper and lower gastrointestinal (GI) endoscopic evaluations. The diagnosis and management of patients with OGIB is particularly challenging because of the length and complex loops of the small intestine. Capsule endoscopy (CE) is 1 diagnostic modality that is used to determine the etiology of bleeding. Objectives The objective of this analysis was to review the diagnostic accuracy, safety, and impact on health outcomes of CE in patients with OGIB in comparison with other diagnostic modalities. Data Sources A literature search was performed using Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid Embase, the Wiley Cochrane Library, and the Centre for Reviews and Dissemination database, for studies published between 2007 and 2013. Review Methods Data on diagnostic accuracy, safety, and impact on health outcomes were abstracted from included studies. Quality of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Results The search yielded 1,189 citations, and 24 studies were included. Eight studies reported diagnostic accuracy comparing CE with other diagnostic modalities. Capsule endoscopy has a higher sensitivity and lower specificity than magnetic resonance enteroclysis, computed tomography, and push enteroscopy. Capsule endoscopy has a good safety profile with few adverse events, although comparative safety data with other diagnostic modalities are limited. Capsule endoscopy is associated with no difference in patient health-related outcomes such as rebleeding or follow-up treatment compared with push enteroscopy, small-bowel follow-through, and angiography. Limitations There was significant heterogeneity in estimates of diagnostic accuracy, which prohibited a statistical summary of findings. The analysis was also limited by the fact that there is no

  4. HerMES: The Far-infrared Emission from Dust-obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Calanog, J. A.; Wardlow, J.; Fu, Hai; Cooray, A.; Assef, R. J.; Bock, J.; Casey, C. M.; Conley, A.; Farrah, D.; Ibar, E.; Kartaltepe, J.; Magdis, G.; Marchetti, L.; Oliver, S. J.; Pérez-Fournon, I.; Riechers, D.; Rigopoulou, D.; Roseboom, I. G.; Schulz, B.; Scott, Douglas; Symeonidis, M.; Vaccari, M.; Viero, M.; Zemcov, M.

    2013-09-01

    Dust-obscured galaxies (DOGs) are an ultraviolet-faint, infrared-bright galaxy population that reside at z ~ 2 and are believed to be in a phase of dusty star-forming and active galactic nucleus (AGN) activity. We present far-infrared (far-IR) observations of a complete sample of DOGs in the 2 deg2 of the Cosmic Evolution Survey. The 3077 DOGs have langzrang = 1.9 ± 0.3 and are selected from 24 μm and r + observations using a color cut of r + - [24] >= 7.5 (AB mag) and S 24 >= 100 μJy. Based on the near-IR spectral energy distributions, 47% are bump DOGs (star formation dominated) and 10% are power-law DOGs (AGN-dominated). We use SPIRE far-IR photometry from the Herschel Multi-tiered Extragalactic Survey to calculate the IR luminosity and characteristic dust temperature for the 1572 (51%) DOGs that are detected at 250 μm (>=3σ). For the remaining 1505 (49%) that are undetected, we perform a median stacking analysis to probe fainter luminosities. Herschel-detected and undetected DOGs have average luminosities of (2.8 ± 0.4) × 1012 L ⊙ and (0.77 ± 0.08) × 1012 L ⊙, and dust temperatures of (33 ± 7) K and (37 ± 5) K, respectively. The IR luminosity function for DOGs with S 24 >= 100 μJy is calculated, using far-IR observations and stacking. DOGs contribute 10%-30% to the total star formation rate (SFR) density of the universe at z = 1.5-2.5, dominated by 250 μm detected and bump DOGs. For comparison, DOGs contribute 30% to the SFR density for all z = 1.5-2.5 galaxies with S 24 >= 100 μJy. DOGs have a large scatter about the star formation main sequence and their specific SFRs show that the observed phase of star formation could be responsible for their total observed stellar mass at z ~ 2.

  5. HerMES: THE FAR-INFRARED EMISSION FROM DUST-OBSCURED GALAXIES

    SciTech Connect

    Calanog, J. A.; Wardlow, J.; Fu, Hai; Cooray, A.; Assef, R. J.; Bock, J.; Riechers, D.; Schulz, B.; Casey, C. M.; Conley, A.; Farrah, D.; Oliver, S. J.; Roseboom, I. G.; Ibar, E.; Kartaltepe, J.; Magdis, G.; Rigopoulou, D.; Marchetti, L.; Pérez-Fournon, I.; Scott, Douglas; and others

    2013-09-20

    Dust-obscured galaxies (DOGs) are an ultraviolet-faint, infrared-bright galaxy population that reside at z ∼ 2 and are believed to be in a phase of dusty star-forming and active galactic nucleus (AGN) activity. We present far-infrared (far-IR) observations of a complete sample of DOGs in the 2 deg{sup 2} of the Cosmic Evolution Survey. The 3077 DOGs have (z) = 1.9 ± 0.3 and are selected from 24 μm and r {sup +} observations using a color cut of r {sup +} – [24] ≥ 7.5 (AB mag) and S{sub 24} ≥ 100 μJy. Based on the near-IR spectral energy distributions, 47% are bump DOGs (star formation dominated) and 10% are power-law DOGs (AGN-dominated). We use SPIRE far-IR photometry from the Herschel Multi-tiered Extragalactic Survey to calculate the IR luminosity and characteristic dust temperature for the 1572 (51%) DOGs that are detected at 250 μm (≥3σ). For the remaining 1505 (49%) that are undetected, we perform a median stacking analysis to probe fainter luminosities. Herschel-detected and undetected DOGs have average luminosities of (2.8 ± 0.4) × 10{sup 12} L{sub ☉} and (0.77 ± 0.08) × 10{sup 12} L{sub ☉}, and dust temperatures of (33 ± 7) K and (37 ± 5) K, respectively. The IR luminosity function for DOGs with S{sub 24} ≥ 100 μJy is calculated, using far-IR observations and stacking. DOGs contribute 10%-30% to the total star formation rate (SFR) density of the universe at z = 1.5-2.5, dominated by 250 μm detected and bump DOGs. For comparison, DOGs contribute 30% to the SFR density for all z = 1.5-2.5 galaxies with S{sub 24} ≥ 100 μJy. DOGs have a large scatter about the star formation main sequence and their specific SFRs show that the observed phase of star formation could be responsible for their total observed stellar mass at z ∼ 2.

  6. Chase the direct impact of rainfall into groundwater in Mt. Fuji from multiple analyses including microbial DNA

    NASA Astrophysics Data System (ADS)

    Kato, Kenji; Sugiyama, Ayumi; Nagaosa, Kazuyo; Tsujimura, Maki

    2016-04-01

    A huge amount of groundwater is stored in subsurface environment of Mt. Fuji, the largest volcanic mountain in Japan. Based on the concept of piston flow transport of groundwater an apparent residence time was estimated to ca. 30 years by 36Cl/Cl ratio (Tosaki et al., 2011). However, this number represents an averaged value of the residence time of groundwater which had been mixed before it flushes out. We chased signatures of direct impact of rainfall into groundwater to elucidate the routes of groundwater, employing three different tracers; stable isotopic analysis (delta 18O), chemical analysis (concentration of silica) and microbial DNA analysis. Though chemical analysis of groundwater shows an averaged value of the examined water which was blended by various water with different sources and routes in subsurface environment, microbial DNA analysis may suggest the place where they originated, which may give information of the source and transport routes of the water examined. Throughout the in situ observation of four rainfall events showed that stable oxygen isotopic ratio of spring water and shallow groundwater obtained from 726m a.s.l. where the average recharge height of rainfall was between 1500 and 1800 m became higher than the values before a torrential rainfall, and the concentration of silica decreased after this event when rainfall exceeded 300 mm in precipitation of an event. In addition, the density of Prokaryotes in spring water apparently increased. Those changes did not appear when rainfall did not exceed 100 mm per event. Thus, findings shown above indicated a direct impact of rainfall into shallow groundwater, which appeared within a few weeks of torrential rainfall in the studied geological setting. In addition, increase in the density of Archaea observed at deep groundwater after the torrential rainfall suggested an enlargement of the strength of piston flow transport through the penetration of rainfall into deep groundwater. This finding was

  7. In College Classrooms, the Problem Is High School Athletics

    ERIC Educational Resources Information Center

    Conn, Steven

    2012-01-01

    As professional sports grew into a multibillion-dollar enterprise, colleges followed suit. Small programs grew big; big programs grew huge, all chasing ESPN glory and cash. So, in turn, high school athletics programs grow, emulating their big siblings. There is a widespread consensus that the nation's public education systems are in serious…

  8. NuSTAR and XMM-Newton observations of luminous, heavily obscured, WISE-selected quasars at z ∼ 2

    SciTech Connect

    Stern, D.; Eisenhardt, P. R. M.; Lansbury, G. B.; Alexander, D. M.; Del Moro, A.; Gandhi, P.; Assef, R. J.; Brandt, W. N.; Griffith, R. L.; Ballantyne, D. R.; Baloković, M.; Bridge, C.; Bauer, F. E.; Benford, D.; Blain, A.; Boggs, S. E.; Craig, W. W.; Brightman, M.; Christensen, F. E.; Comastri, A.; and others

    2014-10-20

    We report on a NuSTAR and XMM-Newton program that has observed a sample of three extremely luminous, heavily obscured WISE-selected active galactic nuclei (AGNs) at z ∼ 2 across a broad X-ray band (0.1 – 79 keV). The parent sample, selected to be faint or undetected in the WISE 3.4 μm (W1) and 4.6 μm (W2) bands but bright at 12 μm (W3) and 22 μm (W4), are extremely rare, with only ∼1000 so-called 'W1W2-dropouts' across the extragalactic sky. Optical spectroscopy reveals typical redshifts of z ∼ 2 for this population, implying rest-frame mid-IR luminosities of νL {sub ν}(6 μm) ∼ 6 × 10{sup 46} erg s{sup –1} and bolometric luminosities that can exceed L {sub bol} ∼ 10{sup 14} L {sub ☉}. The corresponding intrinsic, unobscured hard X-ray luminosities are L(2-10 keV) ∼ 4 × 10{sup 45} erg s{sup –1} for typical quasar templates. These are among the most AGNs known, though the optical spectra rarely show evidence of a broad-line region and the selection criteria imply heavy obscuration even at rest-frame 1.5 μm. We designed our X-ray observations to obtain robust detections for gas column densities N {sub H} ≤ 10{sup 24} cm{sup –2}. In fact, the sources prove to be fainter than these predictions. Two of the sources were observed by both NuSTAR and XMM-Newton, with neither being detected by NuSTAR (f {sub 3-24} {sub keV} ≲ 10{sup –13} erg cm{sup –2} s{sup –1}), and one being faintly detected by XMM-Newton (f {sub 0.5-10} {sub keV} ∼ 5 × 10{sup –15} erg cm{sup –2} s{sup –1}). A third source was observed only with XMM-Newton, yielding a faint detection (f {sub 0.5-10} {sub keV} ∼ 7 × 10{sup –15} erg cm{sup –2} s{sup –1}). The X-ray data imply these sources are either X-ray weak, or are heavily obscured by column densities N {sub H} ≳ 10{sup 24} cm{sup –2}. The combined X-ray and mid-IR analysis seems to favor this second possibility, implying the sources are extremely obscured, consistent with Compton

  9. Real-time measurements of nitrogen oxide emissions from in-use New York City transit buses using a chase vehicle.

    PubMed

    Shorter, Joanne H; Herndon, Scott; Zahniser, Mark S; Nelson, David D; Wormhoudt, Joda; Demerjian, Kenneth L; Kolb, Charles E

    2005-10-15

    New diesel engine technologies and alternative fuel engines are being introduced into fleets of mass transit buses to try to meet stricter emission regulations of nitrogen oxides and particulates: Real-time instruments including an Aerodyne Research tunable infrared laser differential absorption spectrometer (TILDAS) were deployed in a mobile laboratory to assess the impact of the implementation of the new technologies on nitrogen oxide emissions in real world driving conditions. Using a "chase" vehicle sampling strategy, the mobile laboratory followed target vehicles, repeatedly sampling their exhaust. Nitrogen oxides from approximately 170 in-use New York City mass transit buses were sampled during the field campaigns. Emissions from conventional diesel buses, diesel buses with continuously regenerating technology (CRT), diesel hybrid electric buses, and compressed natural gas (CNG) buses were compared. The chase vehicle sampling method yields real world emissions that can be included in more realistic emission inventories. The NO, emissions from the diesel and CNG buses were comparable. The hybrid electric buses had approximately one-half the NOx emissions. In CRT diesels, NO2 accounts for about one-third of the NOx emitted in the exhaust, while for non-CRT buses the NO2 fraction is less than 10%.

  10. Chasing the Silver Dragon

    NASA Astrophysics Data System (ADS)

    Berry, Michael

    2015-07-01

    Occurring on only a few dozen rivers around the world, tidal bores are as rare as they are intriguing. Michael Berry outlines the science behind this natural phenomenon and describes his sighting in China of one of the most spectacular bores of them all.

  11. Chasing Ecological Interactions.

    PubMed

    Jordano, Pedro

    2016-09-01

    Basic research on biodiversity has concentrated on individual species-naming new species, studying distribution patterns, and analyzing their evolutionary relationships. Yet biodiversity is more than a collection of individual species; it is the combination of biological entities and processes that support life on Earth. To understand biodiversity we must catalog it, but we must also assess the ways species interact with other species to provide functional support for the Tree of Life. Ecological interactions may be lost well before the species involved in those interactions go extinct; their ecological functions disappear even though they remain. Here, I address the challenges in studying the functional aspects of species interactions and how basic research is helping us address the fast-paced extinction of species due to human activities.

  12. Chasing the Dream

    ERIC Educational Resources Information Center

    Gardezi, Aleena

    2012-01-01

    Community colleges are gearing up to play a greater role in providing open access and affordable education to undocumented immigrants since President Barack Obama's re-election, which ensured the continuance of his June 15th executive order offering deferred deportation to eligible young immigrants. That order provided an opportunity for children…

  13. Chasing Ecological Interactions.

    PubMed

    Jordano, Pedro

    2016-09-01

    Basic research on biodiversity has concentrated on individual species-naming new species, studying distribution patterns, and analyzing their evolutionary relationships. Yet biodiversity is more than a collection of individual species; it is the combination of biological entities and processes that support life on Earth. To understand biodiversity we must catalog it, but we must also assess the ways species interact with other species to provide functional support for the Tree of Life. Ecological interactions may be lost well before the species involved in those interactions go extinct; their ecological functions disappear even though they remain. Here, I address the challenges in studying the functional aspects of species interactions and how basic research is helping us address the fast-paced extinction of species due to human activities. PMID:27631692

  14. Chasing Unachievable Outcomes

    ERIC Educational Resources Information Center

    Pangrazi, Robert P.

    2010-01-01

    Today, teachers complain about the lack of physical education time and the lack of physical education programming. In addition, a great deal of time is spent advocating the relationship between "healthy mind-healthy body." Today's drive to show a relationship between physical fitness/activity and academic achievement is really not different than…

  15. Chasing the Moon's Shadow.

    ERIC Educational Resources Information Center

    Bell, Trudy E.

    1991-01-01

    Suggestions and tips for novice and experienced eclipse watchers are provided. Discussed are the mysterious shadow bands that occur just minutes before an eclipse. Directions for building a deluxe pinhole projector for observing the eclipse, a reading list, and a glossary of related terms are included. (KR)

  16. Infants' Perception of Chasing

    ERIC Educational Resources Information Center

    Frankenhuis, Willem E.; House, Bailey; Barrett, H. Clark; Johnson, Scott P.

    2013-01-01

    Two significant questions in cognitive and developmental science are first, whether objects and events are selected for attention based on their features (featural processing) or the configuration of their features (configural processing), and second, how these modes of processing develop. These questions have been addressed in part with…

  17. Chasing Ecological Interactions

    PubMed Central

    2016-01-01

    Basic research on biodiversity has concentrated on individual species—naming new species, studying distribution patterns, and analyzing their evolutionary relationships. Yet biodiversity is more than a collection of individual species; it is the combination of biological entities and processes that support life on Earth. To understand biodiversity we must catalog it, but we must also assess the ways species interact with other species to provide functional support for the Tree of Life. Ecological interactions may be lost well before the species involved in those interactions go extinct; their ecological functions disappear even though they remain. Here, I address the challenges in studying the functional aspects of species interactions and how basic research is helping us address the fast-paced extinction of species due to human activities. PMID:27631692

  18. The "Wild Goose" Chase

    ERIC Educational Resources Information Center

    Bright, Donald B.

    1973-01-01

    Describes a five-day, five-station oceanographic cruise off the coast of southern California designed to provide practical field experience for college students enrolled in marine science courses. (JR)

  19. The Spectral Energy Distributions and Infrared Luminosities of z ≈ 2 Dust-obscured Galaxies from Herschel and Spitzer

    NASA Astrophysics Data System (ADS)

    Melbourne, J.; Soifer, B. T.; Desai, Vandana; Pope, Alexandra; Armus, Lee; Dey, Arjun; Bussmann, R. S.; Jannuzi, B. T.; Alberts, Stacey

    2012-05-01

    Dust-obscured galaxies (DOGs) are a subset of high-redshift (z ≈ 2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L IR > 1012 L ⊙). We present new far-infrared photometry, at 250, 350, and 500 μm (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 1011.6 L ⊙ 1013 L ⊙. The rest-frame near-IR (1-3 μm) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths. DOGs with "power-law" SEDs in the rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to the QSO-like local ULIRG, Mrk 231. DOGs with a stellar "bump" in their rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to local star-bursting ULIRGs like NGC 6240. None show 250/24 μm flux density ratios similar to extreme local ULIRG, Arp 220; though three show 350/24 μm flux density ratios similar to Arp 220. For the Herschel-detected DOGs, accurate estimates (within ~25%) of total IR luminosity can be predicted from their rest-frame mid-IR data alone (e.g., from Spitzer observed-frame 24 μm luminosities). Herschel-detected DOGs tend to have a high ratio of infrared luminosity to rest-frame 8 μm luminosity (the IR8 = L IR(8-1000 μm)/νL ν(8 μm) parameter of Elbaz et al.). Instead of lying on the z = 1-2 "infrared main sequence" of star-forming galaxies (like typical LIRGs and ULIRGs at those epochs) the DOGs, especially large fractions of the bump sources, tend to lie in the starburst sequence. While, Herschel-detected DOGs are similar to scaled up

  20. OBSCURED GOODS ACTIVE GALACTIC NUCLEI AND THEIR HOST GALAXIES AT z < 1.25: THE SLOW BLACK HOLE GROWTH PHASE

    SciTech Connect

    Simmons, B. D.; Urry, C. M.; Van Duyne, J.; Treister, E.; Koekemoer, A. M.; Grogin, N. A.

    2011-06-20

    We compute black hole masses and bolometric luminosities for 87 obscured active galactic nuclei (AGNs) in the redshift range 0.25 {<=} z {<=} 1.25, selected from the GOODS deep multi-wavelength survey fields via their X-ray emission. We fit the optical images and obtain morphological parameters for the host galaxy, separating the galaxy from its central point source, thereby obtaining a four-band optical spectral energy distribution (SED) for each active nucleus. We calculate bolometric luminosities for these AGNs by reddening a normalized mean SED of GOODS broad-line AGNs to match the observed central point-source SED of each obscured AGN. This estimate of L{sub bol} has a smaller spread than simple bolometric corrections to the X-ray luminosity or direct integration of the observed multi-wavelength SED, suggesting it is a better measure. We estimate central black hole masses from the bulge luminosities. The black hole masses span a wide range, 7 x 10{sup 6} M{sub sun} to 6 x 10{sup 9} M{sub sun}; the median black hole mass is 5 x 10{sup 8} M{sub sun}. The majority of these AGNs have L/L{sub Edd} {<=} 0.01, and we detect no significant evolution of the mean Eddington ratio to z = 1.25. This implies that the bulk of black hole growth in these obscured AGNs must have occurred at z {approx}> 1 and that we are observing these AGNs in a slow- or no-growth state.

  1. Heavily reddened type 1 quasars at z > 2 - I. Evidence for significant obscured black hole growth at the highest quasar luminosities

    NASA Astrophysics Data System (ADS)

    Banerji, Manda; Alaghband-Zadeh, S.; Hewett, Paul C.; McMahon, Richard G.

    2015-03-01

    We present a new population of z > 2 dust-reddened, type 1 quasars with 0.5 ≲ E(B - V) ≲ 1.5, selected using near-infrared (NIR) imaging data from the UKIDSS-LAS (Large Area Survey), ESO-VHS (European Southern Obseratory-VISTA Hemisphere Survey) and WISE surveys. NIR spectra obtained using the Very Large Telescope for 24 new objects bring our total sample of spectroscopically confirmed hyperluminous (>1013 L⊙), high-redshift dusty quasars to 38. There is no evidence for reddened quasars having significantly different Hα equivalent widths relative to unobscured quasars. The average black hole masses (˜109-1010 M⊙) and bolometric luminosities (˜1047 erg s-1) are comparable to the most luminous unobscured quasars at the same redshift, but with a tail extending to very high luminosities of ˜1048 erg s-1. 66 per cent of the reddened quasars are detected at >3σ at 22 μm by WISE. The average 6-μm rest-frame luminosity is log10(L6 μm/ erg s-1) = 47.1 ± 0.4, making the objects among the mid-infrared brightest active galactic nuclei (AGN) currently known. The extinction-corrected space density estimate now extends over three magnitudes (-30 < Mi < -27) and demonstrates that the reddened quasar luminosity function is significantly flatter than that of the unobscured quasar population at z = 2-3. At the brightest magnitudes, Mi ≲ -29, the space density of our dust-reddened population exceeds that of unobscured quasars. A model where the probability that a quasar becomes dust reddened increases at high luminosity is consistent with the observations and such a dependence could be explained by an increase in luminosity and extinction during AGN-fuelling phases. The properties of our obscured type 1 quasars are distinct from the heavily obscured, Compton-thick AGN that have been identified at much fainter luminosities and we conclude that they likely correspond to a brief evolutionary phase in massive galaxy formation.

  2. Obscure phenomena in statistical analysis of quantitative structure-activity relationships. Part 1: Multicollinearity of physicochemical descriptors.

    PubMed

    Mager, P P; Rothe, H

    1990-10-01

    Multicollinearity of physicochemical descriptors leads to serious consequences in quantitative structure-activity relationship (QSAR) analysis, such as incorrect estimators and test statistics of regression coefficients of the ordinary least-squares (OLS) model applied usually to QSARs. Beside the diagnosis of the known simple collinearity, principal component regression analysis (PCRA) also allows the diagnosis of various types of multicollinearity. Only if the absolute values of PCRA estimators are order statistics that decrease monotonically, the effects of multicollinearity can be circumvented. Otherwise, obscure phenomena may be observed, such as good data recognition but low predictive model power of a QSAR model.

  3. Relative contributions of rhizosphere and microbial respiration to belowground and total ecosystem respiration in arctic tussock tundra: results of a 13C pulse-chase experiment

    NASA Astrophysics Data System (ADS)

    Segal, A. D.; Sullivan, P.; Weintraub, M. N.; Darrouzet-Nardi, A.; Steltzer, H.

    2011-12-01

    Many arctic ecosystems that have historically been strong carbon (C) sinks are becoming sources of C to the atmosphere. Although ecosystem respiration is the largest C flux out of ecosystems, our ability to model respiration lags considerably behind our ability to model photosynthesis in the Arctic. Understanding the controls on respiration is especially important for an ecosystem which appears to be experiencing the greatest climate warming and also contains large stores of soil C. Partitioning respiration into its component fluxes and identifying factors controlling respiration of each component is a critical first step towards improving our ability to model changes in respiration. However, partitioning belowground constituents has proven to be challenging in most ecosystems. Therefore, to accurately estimate rhizosphere respiration and bulk soil microbial respiration in moist acidic tussock tundra, we selected an isotopic method that results in minimal disturbance of belowground processes. In mid July of 2011, we introduced a 13CO2 label into a clear ecosystem CO2 flux chamber, allowed the vegetation to incorporate the label through photosynthesis and returned 2 days and 4 days after labeling to follow the movement of the 13C signal. A smaller CO2 flux chamber was used to chase the label separately in tussock and inter-tussock areas. All above ground plant tissue was clipped immediately before the chase measurements and soil cores were taken immediately after chasing the label. Syringe samples (n=5 or 6) were collected from the small flux chamber at regular intervals as CO2 concentrations were allowed to build, and Keeling plots were used to estimate δ13C of belowground respiration. After completing the field measurements, the soil cores were sorted into live roots and root free soil. Samples of each were incubated in mason jars placed in a 10°C water bath. The jars were scrubbed free of CO2 and syringe samples were collected from each jar after CO2

  4. PDR MODEL MAPPING OF OBSCURED H{sub 2} EMISSION AND THE LINE-OF-SIGHT STRUCTURE OF M17-SW

    SciTech Connect

    Sheffer, Y.; Wolfire, M. G.

    2013-09-01

    We observed H{sub 2} line emission with Spitzer-IRS toward M17-SW and modeled the data with our photon-dominated region (PDR) code. Derived gas density values of up to few times 10{sup 7} cm{sup -3} indicate that H{sub 2} emission originates in high-density clumps. We discover that the PDR code can be utilized to map the amount of intervening extinction obscuring the H{sub 2} emission layers, and thus we obtain the radial profile of A{sub V} relative to the central ionizing cluster NGC 6618. The extinction has a positive radial gradient, varying between 15-47 mag over the projected distance of 0.9-2.5 pc from the primary ionizer, CEN 1. These high extinction values are in good agreement with previous studies of A{sub V} toward stellar targets in M17-SW. The ratio of data to PDR model values is used to infer the global line-of-sight structure of the PDR surface, which is revealed to resemble a concave surface relative to NGC 6618. Such a configuration confirms that this PDR can be described as a bowl-shaped boundary of the central H II region in M17. The derived structure and physical conditions are important for interpreting the fine-structure and rotational line emission from the PDR.

  5. The hidden quasar nucleus of a WISE-selected, hyperluminous, dust-obscured galaxy at z ~ 2.3

    NASA Astrophysics Data System (ADS)

    Piconcelli, E.; Vignali, C.; Bianchi, S.; Zappacosta, L.; Fritz, J.; Lanzuisi, G.; Miniutti, G.; Bongiorno, A.; Feruglio, C.; Fiore, F.; Maiolino, R.

    2015-02-01

    We present the first X-ray spectrum of a hot dust-obscured galaxy (DOG), namely W1835+4355 at z ~ 2.3. Hot DOGs represent a very rare population of hyperluminous (≥1047 erg s-1), dust-enshrouded objects at z ≥ 2 recently discovered in the WISE All Sky Survey. The 40 ks XMM-Newton spectrum reveals a continuum as flat (Γ ~ 0.8) as typically seen in heavily obscured AGN. This, along with the presence of strong Fe Kα emission, clearly suggests a reflection-dominated spectrum due to Compton-thick absorption. In this scenario, the observed luminosity of L2-10~ 2 × 1044 erg s-1 is a fraction (<10%) of the intrinsic one, which is estimated to be ≳ 5 × 1045 erg s-1 by using several proxies. The Herschel data allow us to constrain the SED up to the sub-mm band, providing a reliable estimate of the quasar contribution (~75%) to the IR luminosity as well as the amount of star formation (~2100 M⊙ yr-1). Our results thus provide additional pieces of evidence that associate Hot DOGs with an exceptionally dusty phase during which luminous quasars and massive galaxies co-evolve and a very efficient and powerful AGN-driven feedback mechanism is predicted by models.

  6. The Far-Infrared Luminosity Function and Star Formation Rate Density for Dust Obscured Galaxies in the Bootes Field

    NASA Astrophysics Data System (ADS)

    Calanog, Jae Alyson; Wardlow, J. L.; Fu, H.; Cooray, A. R.; HerMES

    2013-01-01

    We present the far-Infrared (FIR) luminosity function (LF) and the star-formation rate density (SFRD) for dust-obscured galaxies (DOGs) in the Bootes field at redshift 2. These galaxies are selected by having a large rest frame mid-IR to UV flux density ratio ( > 1000) and are expected to be some of the most luminous and heavily obscured galaxies in the Universe at this epoch. Photometric redshifts for DOGs are estimated from optical and mid-IR data using empirically derived low resolution spectral templates for AGN and galaxies. We use HerMES Herschel-SPIRE data to fit a modified blackbody to calculate the FIR luminosity (LFIR) and dust temperature (Td) for all DOGs individually detected in SPIRE maps. A stacking analyses was implemented to measure a median sub-mm flux of undetected DOGs. We find that DOGs have LIR and Td that are similar with the sub-millimeter galaxy (SMG) population, suggesting these two populations are related. The DOG LF and SFRD at 2 are calculated and compared to SMGs.

  7. ACTIVE GALACTIC NUCLEUS OBSCURATION FROM WINDS: FROM DUSTY INFRARED-DRIVEN TO WARM AND X-RAY PHOTOIONIZED

    PubMed Central

    Dorodnitsyn, A.; Kallman, T.

    2016-01-01

    We present calculations of AGN winds at ~parsec scales, along with the associated obscuration. We take into account the pressure of infrared radiation on dust grains and the interaction of X-rays from a central black hole with hot and cold plasma. Infrared radiation (IR) is incorporated in radiation-hydrodynamic simulations adopting the flux-limited diffusion approximation. We find that in the range of X-ray luminosities L=0.05 – 0.6Ledd, the Compton-thick part of the flow (aka torus) has an opening angle of approximately 72° – 75° regardless of the luminosity. At L ≳ 0.1 the outflowing dusty wind provides the obscuration with IR pressure playing a major role. The global flow consists of two phases: the cold flow at inclinations θ ≳ 70° and a hot, ionized wind of lower density at lower inclinations. The dynamical pressure of the hot wind is important in shaping the denser IR supported flow. At luminosities ≤0.1Ledd episodes of outflow are followed by extended periods when the wind switches to slow accretion. PMID:27642184

  8. The American Society for Gastrointestinal Endoscopy (ASGE) diagnostic algorithm for obscure gastrointestinal bleeding: eight burning questions from everyday clinical practice.

    PubMed

    Rondonotti, Emanuele; Marmo, Riccardo; Petracchini, Massimo; de Franchis, Roberto; Pennazio, Marco

    2013-03-01

    The diagnosis and management of patients with obscure gastrointestinal bleeding are often long and challenging processes. Over the last 10 years the introduction in clinical practice of new diagnostic and therapeutic procedures (i.e. Capsule Endoscopy, Computed Tomographic Enterography, Magnetic Resonance Enterography, and Device Assisted Enteroscopy) has revolutionized the diagnostic/therapeutic work-up of these patients. Based on evidence published in the last 10 years, international scientific societies have proposed new practice guidelines for the management of obscure gastrointestinal bleeding, which include these techniques. However, although these algorithms (the most recent ones are endorsed by the American Society for Gastrointestinal Endoscopy - ASGE) allow the management of the large majority of patients, some issues still remain unsolved. The present paper reports the results of the discussion, based on the literature published up to September 2011, among a panel of experts and gastroenterologists, working with Capsule Endoscopy and with Device Assisted Enteroscopy, attending the 6th annual meeting of the Italian Club for Capsule Endoscopy and Enteroscopy. Eight unresolved issues were selected: each of them is presented as a "Burning question" and the "Answer" is the strategy proposed to manage it, according to both the available evidence and the discussion among participants.

  9. Active Galactic Nucleus Obscuration from Winds: From Dusty Infrared-Driven to Warm and X-Ray Photoionized

    NASA Technical Reports Server (NTRS)

    Dorodnitsyn, Anton V.; Kallman, Timothy R.

    2012-01-01

    We present calculations of active galactic nucleus winds at approx.parsec scales along with the associated obscuration. We take into account the pressure of infrared radiation on dust grains and the interaction of X-rays from a central black hole with hot and cold plasma. Infrared radiation (IR) is incorporated in radiation-hydrodynamic simulations adopting the flux-limited diffusion approximation. We find that in the range of X-ray luminosities L = 0.05-0.6 L(sub Edd), the Compton-thick part of the flow (aka torus) has an opening angle of approximately 72deg - 75deg regardless of the luminosity. At L > or approx. 0.1, the outflowing dusty wind provides the obscuration with IR pressure playing a major role. The global flow consists of two phases: the cold flow at inclinations (theta) > or approx.70deg and a hot, ionized wind of lower density at lower inclinations. The dynamical pressure of the hot wind is important in shaping the denser IR-supported flow. At luminosities < or = 0.1 L(sub Edd) episodes of outflow are followed by extended periods when the wind switches to slow accretion. Key words: acceleration of particles . galaxies: active . hydrodynamics . methods: numerical Online-only material: color figures

  10. Active Galactic Nucleus Obscuration from Winds: From Dusty Infrared-driven to Warm and X-Ray Photoionized.

    PubMed

    Dorodnitsyn, A; Kallman, T

    2012-12-10

    We present calculations of AGN winds at ~parsec scales, along with the associated obscuration. We take into account the pressure of infrared radiation on dust grains and the interaction of X-rays from a central black hole with hot and cold plasma. Infrared radiation (IR) is incorporated in radiation-hydrodynamic simulations adopting the flux-limited diffusion approximation. We find that in the range of X-ray luminosities L=0.05 - 0.6Ledd, the Compton-thick part of the flow (aka torus) has an opening angle of approximately 72° - 75° regardless of the luminosity. At L ≳ 0.1 the outflowing dusty wind provides the obscuration with IR pressure playing a major role. The global flow consists of two phases: the cold flow at inclinations θ ≳ 70° and a hot, ionized wind of lower density at lower inclinations. The dynamical pressure of the hot wind is important in shaping the denser IR supported flow. At luminosities ≤0.1Ledd episodes of outflow are followed by extended periods when the wind switches to slow accretion.

  11. X-ray spectral modelling of the AGN obscuring region in the CDFS: Bayesian model selection and catalogue

    NASA Astrophysics Data System (ADS)

    Buchner, J.; Georgakakis, A.; Nandra, K.; Hsu, L.; Rangel, C.; Brightman, M.; Merloni, A.; Salvato, M.; Donley, J.; Kocevski, D.

    2014-04-01

    Context. Aims: Active galactic nuclei are known to have complex X-ray spectra that depend on both the properties of the accreting super-massive black hole (e.g. mass, accretion rate) and the distribution of obscuring material in its vicinity (i.e. the "torus"). Often however, simple and even unphysical models are adopted to represent the X-ray spectra of AGN, which do not capture the complexity and diversity of the observations. In the case of blank field surveys in particular, this should have an impact on e.g. the determination of the AGN luminosity function, the inferred accretion history of the Universe and also on our understanding of the relation between AGN and their host galaxies. Methods: We develop a Bayesian framework for model comparison and parameter estimation of X-ray spectra. We take into account uncertainties associated with both the Poisson nature of X-ray data and the determination of source redshift using photometric methods. We also demonstrate how Bayesian model comparison can be used to select among ten different physically motivated X-ray spectral models the one that provides a better representation of the observations. This methodology is applied to X-ray AGN in the 4 Ms Chandra Deep Field South. Results: For the ~350 AGN in that field, our analysis identifies four components needed to represent the diversity of the observed X-ray spectra: (1) an intrinsic power law; (2) a cold obscurer which reprocesses the radiation due to photo-electric absorption, Compton scattering and Fe-K fluorescence; (3) an unabsorbed power law associated with Thomson scattering off ionised clouds; and (4) Compton reflection, most noticeable from a stronger-than-expected Fe-K line. Simpler models, such as a photo-electrically absorbed power law with a Thomson scattering component, are ruled out with decisive evidence (B > 100). We also find that ignoring the Thomson scattering component results in underestimation of the inferred column density, NH, of the obscurer

  12. THE SPITZER MID-INFRARED ACTIVE GALACTIC NUCLEUS SURVEY. I. OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF OBSCURED CANDIDATES AND NORMAL ACTIVE GALACTIC NUCLEI SELECTED IN THE MID-INFRARED

    SciTech Connect

    Lacy, M.; Ridgway, S. E.; Gates, E. L.; Petric, A. O.; Sajina, A.; Urrutia, T.; Cox Drews, S.; Harrison, C.; Seymour, N.; Storrie-Lombardi, L. J.

    2013-10-01

    We present the results of a program of optical and near-infrared spectroscopic follow-up of candidate active galactic nuclei (AGNs) selected in the mid-infrared. This survey selects both normal and obscured AGNs closely matched in luminosity across a wide range, from Seyfert galaxies with bolometric luminosities L {sub bol} ∼ 10{sup 10} L {sub ☉} to highly luminous quasars (L {sub bol} ∼ 10{sup 14} L {sub ☉}), all with redshifts ranging from 0 to 4.3. Samples of candidate AGNs were selected with mid-infrared color cuts at several different 24 μm flux density limits to ensure a range of luminosities at a given redshift. The survey consists of 786 candidate AGNs and quasars, of which 672 have spectroscopic redshifts and classifications. Of these, 137 (20%) are type 1 AGNs with blue continua, 294 (44%) are type 2 objects with extinctions A{sub V} ∼> 5 toward their AGNs, 96 (14%) are AGNs with lower extinctions (A{sub V} ∼ 1), and 145 (22%) have redshifts, but no clear signs of AGN activity in their spectra. Of the survey objects 50% have L {sub bol} > 10{sup 12} L {sub ☉}, in the quasar regime. We present composite spectra for type 2 quasars and objects with no signs of AGN activity in their spectra. We also discuss the mid-infrared—emission-line luminosity correlation and present the results of cross correlations with serendipitous X-ray and radio sources. The results show that: (1) obscured objects dominate the overall AGN population, (2) mid-infrared selected AGN candidates exist which lack AGN signatures in their optical spectra but have AGN-like X-ray or radio counterparts, and (3) X-ray and optical classifications of obscured and unobscured AGNs often differ.

  13. NuSTAR J033202-2746.8: Direct constraints on the Compton reflection in a heavily obscured quasar at z ≈ 2

    SciTech Connect

    Del Moro, A.; Mullaney, J. R.; Alexander, D. M.; Aird, J. A.; Gandhi, P.; Comastri, A.; Vignali, C.; Gilli, R.; Bauer, F. E.; Treister, E.; Stern, D.; Civano, F.; Ranalli, P.; Ballantyne, D. R.; Baloković, M.; Boggs, S. E.; Brandt, W. N.; Christensen, F. E.; Craig, W. W.; Hailey, C. J.; and others

    2014-05-01

    We report Nuclear Spectroscopic Telescope Array (NuSTAR) observations of NuSTAR J033202-2746.8, a heavily obscured, radio-loud quasar detected in the Extended Chandra Deep Field-South, the deepest layer of the NuSTAR extragalactic survey (∼400 ks, at its deepest). NuSTAR J033202-2746.8 is reliably detected by NuSTAR only at E > 8 keV and has a very flat spectral slope in the NuSTAR energy band (Γ=0.55{sub −0.64}{sup +0.62}; 3-30 keV). Combining the NuSTAR data with extremely deep observations by Chandra and XMM-Newton (4 Ms and 3 Ms, respectively), we constrain the broad-band X-ray spectrum of NuSTAR J033202-2746.8, indicating that this source is a heavily obscured quasar (N{sub H}=5.6{sub −0.8}{sup +0.9}×10{sup 23} cm{sup –2}) with luminosity L {sub 10-40} {sub keV} ≈ 6.4 × 10{sup 44} erg s{sup –1}. Although existing optical and near-infrared (near-IR) data, as well as follow-up spectroscopy with the Keck and VLT telescopes, failed to provide a secure redshift identification for NuSTAR J033202-2746.8, we reliably constrain the redshift z = 2.00 ± 0.04 from the X-ray spectral features (primarily from the iron K edge). The NuSTAR spectrum shows a significant reflection component (R=0.55{sub −0.37}{sup +0.44}), which was not constrained by previous analyses of Chandra and XMM-Newton data alone. The measured reflection fraction is higher than the R ∼ 0 typically observed in bright radio-loud quasars such as NuSTAR J033202-2746.8, which has L {sub 1.4} {sub GHz} ≈ 10{sup 27} W Hz{sup –1}. Constraining the spectral shape of active galactic nuclei (AGNs), including bright quasars, is very important for understanding the AGN population, and can have a strong impact on the modeling of the X-ray background. Our results show the importance of NuSTAR in investigating the broad-band spectral properties of quasars out to high redshift.

  14. NuSTAR J033202-2746.8: Direct Constraints on the Compton Reflection in a Heavily Obscured Quasar at z ≈ 2

    NASA Astrophysics Data System (ADS)

    Del Moro, A.; Mullaney, J. R.; Alexander, D. M.; Comastri, A.; Bauer, F. E.; Treister, E.; Stern, D.; Civano, F.; Ranalli, P.; Vignali, C.; Aird, J. A.; Ballantyne, D. R.; Baloković, M.; Boggs, S. E.; Brandt, W. N.; Christensen, F. E.; Craig, W. W.; Gandhi, P.; Gilli, R.; Hailey, C. J.; Harrison, F. A.; Hickox, R. C.; LaMassa, S. M.; Lansbury, G. B.; Luo, B.; Puccetti, S.; Urry, M.; Zhang, W. W.

    2014-05-01

    We report Nuclear Spectroscopic Telescope Array (NuSTAR) observations of NuSTAR J033202-2746.8, a heavily obscured, radio-loud quasar detected in the Extended Chandra Deep Field-South, the deepest layer of the NuSTAR extragalactic survey (~400 ks, at its deepest). NuSTAR J033202-2746.8 is reliably detected by NuSTAR only at E > 8 keV and has a very flat spectral slope in the NuSTAR energy band (\\Gamma =0.55^{+0.62}_{-0.64}; 3-30 keV). Combining the NuSTAR data with extremely deep observations by Chandra and XMM-Newton (4 Ms and 3 Ms, respectively), we constrain the broad-band X-ray spectrum of NuSTAR J033202-2746.8, indicating that this source is a heavily obscured quasar (N_H=5.6^{+0.9}_{-0.8}\\times 10^{23} cm-2) with luminosity L 10-40 keV ≈ 6.4 × 1044 erg s-1. Although existing optical and near-infrared (near-IR) data, as well as follow-up spectroscopy with the Keck and VLT telescopes, failed to provide a secure redshift identification for NuSTAR J033202-2746.8, we reliably constrain the redshift z = 2.00 ± 0.04 from the X-ray spectral features (primarily from the iron K edge). The NuSTAR spectrum shows a significant reflection component (R=0.55^{+0.44}_{-0.37}), which was not constrained by previous analyses of Chandra and XMM-Newton data alone. The measured reflection fraction is higher than the R ~ 0 typically observed in bright radio-loud quasars such as NuSTAR J033202-2746.8, which has L 1.4 GHz ≈ 1027 W Hz-1. Constraining the spectral shape of active galactic nuclei (AGNs), including bright quasars, is very important for understanding the AGN population, and can have a strong impact on the modeling of the X-ray background. Our results show the importance of NuSTAR in investigating the broad-band spectral properties of quasars out to high redshift.

  15. SR-71A Taking Off with Test Fixture Mounted Atop the Aft Section of the Aircraft and F-18 Chase Airc

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This photo shows a NASA's SR-71A Blackbird, followed by a NASA F/A-18 chase plane, taking off from the runway at the Dryden Flight Research Center, Edwards, California, on a 1999 flight. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward

  16. Another short-burst host galaxy with an optically obscured high star formation rate: The case of GRB 071227

    SciTech Connect

    Nicuesa Guelbenzu, A.; Klose, S.; Kann, D. A.; Rossi, A.; Schmidl, S.; Michałowski, M. J.; McKenzie, M. R. G.; Savaglio, S.; Greiner, J.; Hunt, L. K.; Gorosabel, J.

    2014-07-01

    We report on radio continuum observations of the host galaxy of the short gamma-ray burst 071227 (z = 0.381) with the Australia Telescope Compact Array. We detect the galaxy in the 5.5 GHz band with an integrated flux density of F {sub ν} = 43 ± 11 μJy, corresponding to an unobscured star-formation rate of about 24 M {sub ☉} yr{sup –1}, 40 times higher than what was found from optical emission lines. Among the ∼30 well-identified and studied host galaxies of short bursts this is the third case where the host is found to undergo an episode of intense star formation. This suggests that a fraction of all short-burst progenitors hosted in star-forming galaxies could be physically related to recent star formation activity, implying a relatively short merger timescale.

  17. Characterization of on-road vehicle emissions in the Mexico City Metropolitan Area using a mobile laboratory in chase and fleet average measurement modes during the MCMA-2003 field campaign

    NASA Astrophysics Data System (ADS)

    Zavala, M.; Herndon, S. C.; Slott, R. S.; Dunlea, E. J.; Marr, L. C.; Shorter, J. H.; Zahniser, M.; Knighton, W. B.; Rogers, T. M.; Kolb, C. E.; Molina, L. T.; Molina, M. J.

    2006-11-01

    A mobile laboratory was used to measure on-road vehicle emission ratios during the MCMA-2003 field campaign held during the spring of 2003 in the Mexico City Metropolitan Area (MCMA). The measured emission ratios represent a sample of emissions of in-use vehicles under real world driving conditions for the MCMA. From the relative amounts of NOx and selected VOC's sampled, the results indicate that the technique is capable of differentiating among vehicle categories and fuel type in real world driving conditions. Emission ratios for NOx, NOy, NH3, H2CO, CH3CHO, and other selected volatile organic compounds (VOCs) are presented for chase sampled vehicles in the form of frequency distributions as well as estimates for the fleet averaged emissions. Our measurements of emission ratios for both CNG and gasoline powered "colectivos" (public transportation buses that are intensively used in the MCMA) indicate that - in a mole per mole basis - have significantly larger NOx and aldehydes emissions ratios as compared to other sampled vehicles in the MCMA. Similarly, ratios of selected VOCs and NOy showed a strong dependence on traffic mode. These results are compared with the vehicle emissions inventory for the MCMA, other vehicle emissions measurements in the MCMA, and measurements of on-road emissions in U.S. cities. We estimate NOx emissions as 100 600±29 200 metric tons per year for light duty gasoline vehicles in the MCMA for 2003. According to these results, annual NOx emissions estimated in the emissions inventory for this category are within the range of our estimated NOx annual emissions. Our estimates for motor vehicle emissions of benzene, toluene, formaldehyde, and acetaldehyde in the MCMA indicate these species are present in concentrations higher than previously reported. The high motor vehicle aldehyde emissions may have an impact on the photochemistry of urban areas.

  18. Foliage penetration obscuration probability density function analysis from overhead canopy photos for gimbaled linear-mode and Geiger-mode airborne lidar

    NASA Astrophysics Data System (ADS)

    Burton, Robin R.

    2010-04-01

    Three-dimensional (3D) Light Detection And Ranging (LIDAR) systems designed for foliage penetration can produce good bare-earth products in medium to medium-heavy obscuration environments, but product creation becomes increasingly more difficult as the obscuration level increases. A prior knowledge of the obscuration environment over large areas is hard to obtain. The competing factors of area coverage rate and product quality are difficult to balance. Ground-based estimates of obscuration levels are labor intensive and only capture a small portion of the area of interest. Estimates of obscuration levels derived from airborne data require that the area of interest has been collected previously. Recently, there has been a focus on lacunarity (scale dependent measure of translational invariance) to quantify the gap structure of canopies. While this approach is useful, it needs to be evaluated relative to the size of the instantaneous field-of-view (IFOV) of the system under consideration. In this paper, the author reports on initial results to generate not just average obscuration values from overhead canopy photographs, but to generate obscuration probability density functions (PDFs) for both gimbaled linear-mode and geiger-mode airborne LIDAR. In general, gimbaled linear-mode (LM) LIDAR collects data with higher signal-to-noise (SNR), but is limited to smaller areas and cannot collect at higher altitudes. Conversely, geiger-mode (GM) LIDAR has a much lower SNR, but is capable of higher area rates and collecting data at higher altitudes. To date, geiger-mode LIDAR obscurant penetration theory has relied on a single obscuration value, but recent work has extended it to use PDFs1. Whether or not the inclusion of PDFs significantly changes predicted results and more closely matches actual results awaits the generation of PDFs over specific ground truth targets and comparison to actual collections of those ground truth targets. Ideally, examination of individual PDFs

  19. Revealing a Population of Heavily Obscured Active Galactic Nuclei at z ≈ 0.5-1 in the Chandra Deep Field-South

    NASA Astrophysics Data System (ADS)

    Luo, B.; Brandt, W. N.; Xue, Y. Q.; Alexander, D. M.; Brusa, M.; Bauer, F. E.; Comastri, A.; Fabian, A. C.; Gilli, R.; Lehmer, B. D.; Rafferty, D. A.; Schneider, D. P.; Vignali, C.

    2011-10-01

    Heavily obscured (N H >~ 3 × 1023 cm-2) active galactic nuclei (AGNs) not detected even in the deepest X-ray surveys are often considered to be comparably numerous to the unobscured and moderately obscured AGNs. Such sources are required to fit the cosmic X-ray background (XRB) emission in the 10-30 keV band. We identify a numerically significant population of heavily obscured AGNs at z ≈ 0.5-1 in the Chandra Deep Field-South (CDF-S) and Extended Chandra Deep Field-South by selecting 242 X-ray undetected objects with infrared-based star-formation rates (SFRs) substantially higher (a factor of 3.2 or more) than their SFRs determined from the UV after correcting for dust extinction. An X-ray stacking analysis of 23 candidates in the central CDF-S region using the 4 Ms Chandra data reveals a hard X-ray signal with an effective power-law photon index of Γ = 0.6+0.3 -0.4, indicating a significant contribution from obscured AGNs. Based on Monte Carlo simulations, we conclude that 74% ± 25% of the selected galaxies host obscured AGNs, within which ≈95% are heavily obscured and ≈80% are Compton-thick (CT; N H > 1.5 × 1024 cm-2). The heavily obscured objects in our sample are of moderate intrinsic X-ray luminosity (≈(0.9-4) × 1042 erg s-1 in the 2-10 keV band). The space density of the CT AGNs is (1.6 ± 0.5) × 10-4 Mpc-3. The z ≈ 0.5-1 CT objects studied here are expected to contribute ≈1% of the total XRB flux in the 10-30 keV band, and they account for ≈5%-15% of the emission in this energy band expected from all CT AGNs according to population-synthesis models. In the 6-8 keV band, the stacked signal of the 23 heavily obscured candidates accounts for <5% of the unresolved XRB flux, while the unresolved ≈25% of the XRB in this band can probably be explained by a stacking analysis of the X-ray undetected optical galaxies in the CDF-S (a 2.5σ stacked signal). We discuss prospects to identify such heavily obscured objects using future hard X

  20. Design of off-axis four-mirror optical system without obscuration based on free-form surface

    NASA Astrophysics Data System (ADS)

    Huang, Chenxu; Liu, Xin

    2015-11-01

    With the development of modern military technology, the requirements of airborne electro-optical search and tracking system are increasing on target detection and recognition. However, traditional off-axis three-mirror system couldn't meet the requirements for reducing weight and compacting size in some circumstances. Based on Seidel aberration theory, by restricting the aberration functions, the optical system could achieve initial construction parameters. During the designing process, decenters and tilts of mirrors were adjusted continuously to eliminate the obscurations. To balance off-axis aberration and increase angle of view, the free-form mirror was introduced into the optical system. Then an unobstructed optical system with effective focal length of 100 mm, FOV of 16°×16°, and relative aperture as F/7 is designed. The results show that the system structure is compact, with imaging qualities approaching diffraction limit.

  1. The nature of the torus in the heavily obscured AGN Markarian 3: an X-ray study

    NASA Astrophysics Data System (ADS)

    Guainazzi, M.; Risaliti, G.; Awaki, H.; Arevalo, P.; Bauer, F. E.; Bianchi, S.; Boggs, S. E.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Forster, K.; Hailey, C. J.; Harrison, F.; Koss, M.; Longinotti, A.; Markwardt, C.; Marinucci, A.; Matt, G.; Reynolds, C. S.; Ricci, C.; Stern, D.; Svoboda, J.; Walton, D.; Zhang, W.

    2016-08-01

    In this paper, we report the results of an X-ray monitoring campaign on the heavily obscured Seyfert galaxy, Markarian 3, carried out between the fall of 2014 and the spring of 2015 with NuSTAR, Suzaku and XMM-Newton. The hard X-ray spectrum of Markarian 3 is variable on all the time-scales probed by our campaign, down to a few days. The observed continuum variability is due to an intrinsically variable primary continuum seen in transmission through a large, but still Compton-thin column density (NH ˜ 0.8-1.1 × 1024 cm-2). If arranged in a spherical-toroidal geometry, the Compton scattering matter has an opening angle ≃66°, and is seen at a grazing angle through its upper rim (inclination angle ≃70°). We report a possible occultation event during the 2014 campaign. If the torus is constituted by a system of clouds sharing the same column density, this event allows us to constrain their number (17 ± 5) and individual column density, [≃ (4.9 ± 1.5) × 1022 cm-2]. The comparison of IR and X-ray spectroscopic results with state-of-the art `torus' models suggests that at least two-thirds of the X-ray obscuring gas volume might be located within the dust sublimation radius. We report also the discovery of an ionized absorber, characterized by variable resonant absorption lines due to He- and H-like iron. This discovery lends support to the idea that moderate column density absorbers could be due to clouds evaporated at the outer surface of the torus, possibly accelerated by the radiation pressure due to the central AGN emission leaking through the patchy absorber.

  2. Influence of weeds on Argentine ant (Hymenoptera: Formicidae) and obscure mealybug (Hemiptera: Pseudococcidae) in a central California vineyard.

    PubMed

    Costello, Michael J; Welch, Mark D

    2014-06-01

    Obscure mealybug is a pest of grapes in the cool climate regions of coastal California, is found on some vineyard weeds, and is tended by the Argentine ant. A study was conducted at a vineyard in Arroyo Grande, CA, to evaluate the impact of weeds on ant activity on grapevines, and the role that ants and weeds have on obscure mealybug infestation in grape clusters. The incidence of the fungus Botrytis cinerea was recorded as well. Treatments were weed exclusion versus the presence of weeds, and ant exclusion versus the presence of ants. Ant activity was evaluated weekly using sugar-based monitoring stations, and mealybug infestation and Botrytis incidence of clusters were evaluated at harvest. Ant exclusion reduced the overall number of ant visits by 82%, and ants increased mealybug infestation of clusters by 53%. Ant activity was 33% higher in the weeds treatment, but there was no impact of weeds on mealybug infestation. We suggest that the higher ant activity recorded in the weeds treatment may have been an artifact of the sugar-based sampling method. Botrytis incidence was three times higher with ants, but did not differ between weeds and weed exclusion treatments. The study supports other research showing a relationship between mealybug infestation and the presence of ants, as well as the lack of impact of floor vegetation on mealybug infestation of grape clusters. It is the first report of a relationship between ants and Botrytis, although it is more likely that the higher Botrytis incidence found here is a result of increased mealybug density than a direct effect by ants. PMID:25026682

  3. Influence of weeds on Argentine ant (Hymenoptera: Formicidae) and obscure mealybug (Hemiptera: Pseudococcidae) in a central California vineyard.

    PubMed

    Costello, Michael J; Welch, Mark D

    2014-06-01

    Obscure mealybug is a pest of grapes in the cool climate regions of coastal California, is found on some vineyard weeds, and is tended by the Argentine ant. A study was conducted at a vineyard in Arroyo Grande, CA, to evaluate the impact of weeds on ant activity on grapevines, and the role that ants and weeds have on obscure mealybug infestation in grape clusters. The incidence of the fungus Botrytis cinerea was recorded as well. Treatments were weed exclusion versus the presence of weeds, and ant exclusion versus the presence of ants. Ant activity was evaluated weekly using sugar-based monitoring stations, and mealybug infestation and Botrytis incidence of clusters were evaluated at harvest. Ant exclusion reduced the overall number of ant visits by 82%, and ants increased mealybug infestation of clusters by 53%. Ant activity was 33% higher in the weeds treatment, but there was no impact of weeds on mealybug infestation. We suggest that the higher ant activity recorded in the weeds treatment may have been an artifact of the sugar-based sampling method. Botrytis incidence was three times higher with ants, but did not differ between weeds and weed exclusion treatments. The study supports other research showing a relationship between mealybug infestation and the presence of ants, as well as the lack of impact of floor vegetation on mealybug infestation of grape clusters. It is the first report of a relationship between ants and Botrytis, although it is more likely that the higher Botrytis incidence found here is a result of increased mealybug density than a direct effect by ants.

  4. Low-frequency ultrawideband synthetic aperture radar: frequency subbanding for targets obscured by the ground

    NASA Astrophysics Data System (ADS)

    Happ, Lynn; Le, Francis; Ressler, Marc A.; Kappra, Karl A.

    1996-06-01

    The Army Research Laboratory (ARL) has been investigating the potential of ultra-wideband synthetic aperture radar (UWB SAR) technology to detect and classify targets concealed by subsurface targets and foliage. Our investigative approach is to collect high-quality precision data to support phenomenological investigations of electromagnetic wave propagation through dielectric media. These investigations, in turn, support the development of algorithms for automatic target recognition. In order to achieve these goals, ARL designed and built an impulse (very short pulse) radar to collect data at a variety of test sites to measure and analyze the responses from targets, clutter, and targets embedded in clutter. The UWB BoomSAR, mounted on a 150-foot-high mobile boom lift, collects the high-quality, precision data sets needed for understanding UWB SAR system requirements and foliage penetration and ground penetration phenomenology. The BoomSAR operates with over 1 gigahertz of bandwidth covering a spectrum from 40 MHz to 1 GHz and is fully polarimetric. This bandwidth contains low frequencies needed for ground penetration while also maintaining higher frequency coverage for high resolution imagery. This paper shows a GPEN target area from data collected at Yuma Proving Grounds, AZ in low- and high- frequency subbands.

  5. Constraining Properties of AGN Coronae with NuSTAR: the Case of the Obscured Seyfert 1.9 Nucleus MCG -05-23-016

    NASA Astrophysics Data System (ADS)

    Balokovic, Mislav; Harrison, Fiona

    2016-04-01

    Robust measurements of the high-energy cut-off in the coronal continuum of AGN have long been limited to a small set of the brightest examples and almost exclusively to unobscured nuclei. We report on a direct measurement of the cut-off energy in the nuclear continuum of the obscured Seyfert 1.9 nucleus MCG-05-23-016 with unprecedented precision. The high sensitivity of NuSTAR in the hard X-ray band allows us to clearly disentangle the spectral curvature of the primary continuum from that of the reprocessed component. Using a simple phenomenological spectral model, we measured the cut-off energy to be 116+/-6 keV, while more complex Comptonization models provided independent constraints on the kinetic temperature of the electrons in the corona and its optical depth. Similar to a number of such measurements perfomed with NuSTAR in the past few years, and consistent with analyses of relatively large samples of hard X-ray spectra from the NuSTAR survey of nearby AGN, the optical depth was found to be of order unity for a range of assumed simple geometries. This means that the data are pushing the currently available models to the limits of their validity. In combination with the observations of spectral signatures from the innermost region of the accretion disk, and the observed variability of the high-energy cut-off, these results allow us to constrain the spatial extent of the AGN corona, its inhomogeneity and physical conditions needed to maintain its structure.

  6. Obscuring Power Structures in the Physics Classroom: Linking Teacher Positioning, Student Engagement, and Physics Identity Development

    ERIC Educational Resources Information Center

    Hazari, Zahra; Cass, Cheryl; Beattie, Carrie

    2015-01-01

    In the process of reforming physics education over the last several decades, a tension has developed between engaging students with the content in more conceptually challenging ways and helping them identify with physics so they are personally motivated in their learning. Through comparative case studies of four high school physics teachers, we…

  7. Uncovering Learning Outcomes: Explicating Obscurity in Learning of Aesthetics in Design and Technology Education

    ERIC Educational Resources Information Center

    Haupt, Grietjie; Blignaut, Seugnet

    2008-01-01

    Education and training interventions can be evaluated through the success of learning outcomes. Kirkpatrick's four-level model is a widely accepted and highly popular evaluation tool. However, some criticise the model's shortcomings. This article will examine the extent to which the four-level model can evaluate design and technology students'…

  8. The triggering mechanism and properties of ionized outflows in the nearest obscured quasars

    NASA Astrophysics Data System (ADS)

    Villar Martín, M.; Emonts, B.; Humphrey, A.; Cabrera Lavers, A.; Binette, L.

    2014-06-01

    We have identified ionized outflows in the narrow-line region of all but one Sloan Digital Sky Survey type 2 quasars (QSO2) at z≲0.1 (20/21, detection rate 95 per cent), implying that this is a ubiquitous phenomenon in this object class also at the lowest z. The outflowing gas has high densities (ne≳1000 cm-3) and covers a region the size of a few kpc. This implies ionized outflow masses Moutf ˜ (0.3-2.4) × 106 M⊙ and mass outflow rates Ṁ< few M⊙ yr-1. The triggering mechanism of the outflows is related to the nuclear activity. The QSO2 can be classified into two groups according to the behaviour and properties of the outflowing gas. QSO2 in Group 1 (5/20 objects) show the most extreme turbulence; they have on average higher radio luminosities and higher excess of radio emission. QSO2 in Group 2 (15/20 objects) show less extreme turbulence; they have lower radio luminosities and, on average, lower or no radio excess. We propose that two competing outflow mechanisms are at work: radio jets and accretion disc winds. Radio jet induced outflows are dominant in Group 1, while disc winds dominate in Group 2. We find that the radio jet mode is capable of producing more extreme outflows. To test this interpretation, we predict that (1) high resolution radio imaging will reveal the presence of jets in Group 1 QSO2; (2) the morphology of their extended ionized nebulae must be more highly collimated and kinematically perturbed.

  9. The XMM deep survey in the CDF-S. IX. An X-ray outflow in a luminous obscured quasar at z ≈ 1.6

    NASA Astrophysics Data System (ADS)

    Vignali, C.; Iwasawa, K.; Comastri, A.; Gilli, R.; Lanzuisi, G.; Ranalli, P.; Cappelluti, N.; Mainieri, V.; Georgantopoulos, I.; Carrera, F. J.; Fritz, J.; Brusa, M.; Brandt, W. N.; Bauer, F. E.; Fiore, F.; Tombesi, F.

    2015-11-01

    In active galactic nuclei (AGN)-galaxy co-evolution models, AGN winds and outflows are often invoked to explain why super-massive black holes and galaxies stop growing efficiently at a certain phase of their lives. They are commonly referred to as the leading actors of feedback processes. Evidence of ultra-fast (v ≳ 0.05c) outflows in the innermost regions of AGN has been collected in the past decade by sensitive X-ray observations for sizable samples of AGN, mostly at low redshift. Here we present ultra-deep XMM-Newton and Chandra spectral data of an obscured (NH≈ 2 × 1023 cm-2), intrinsically luminous (L2-10 keV≈ 4 × 1044 erg s-1) quasar (named PID352) at z ≈ 1.6 (derived from the X-ray spectral analysis) in the Chandra Deep Field-South. The source is characterized by an iron emission and absorption line complex at observed energies of E ≈ 2-3 keV. While the emission line is interpreted as being due to neutral iron (consistent with the presence of cold absorption), the absorption feature is due to highly ionized iron transitions (FeXXV, FeXXVI) with an outflowing velocity of , as derived from photoionization models. The mass outflow rate - ~2 M⊙ yr-1 - is similar to the source accretion rate, and the derived mechanical energy rate is ~9.5 × 1044 erg s-1, corresponding to 9% of the source bolometric luminosity. PID352 represents one of the few cases where indications of X-ray outflowing gas have been observed at high redshift thus far. This wind is powerful enough to provide feedback on the host galaxy.

  10. SALT Long-slit Spectroscopy of Luminous Obscured Quasars: An Upper Limit on the Size of the Narrow-line Region?

    NASA Astrophysics Data System (ADS)

    Hainline, Kevin N.; Hickox, Ryan; Greene, Jenny E.; Myers, Adam D.; Zakamska, Nadia L.

    2013-09-01

    We present spatially resolved long-slit spectroscopy from the Southern African Large Telescope to examine the spatial extent of the narrow-line regions (NLRs) of a sample of eight luminous obscured quasars at 0.10 < z < 0.43. Our results are consistent with an observed shallow slope in the relationship between NLR size and L [O III], which has been interpreted to indicate that NLR size is limited by the density and ionization state of the NLR gas rather than the availability of ionizing photons. We also explore how the NLR size scales with a more direct measure of instantaneous active galactic nucleus power using mid-IR photometry from the Wide Field Infrared Explorer, which probes warm to hot dust near the central black hole and so, unlike [O III], does not depend on the properties of the NLR. Using our results as well as samples from the literature, we obtain a power-law relationship between NLR size and L 8 μm that is significantly steeper than that observed for NLR size and L [O III]. We find that the size of the NLR goes approximately as L^{1/2}_{8\\,\\mu {m}}, as expected from the simple scenario of constant-density clouds illuminated by a central ionizing source. We further see tentative evidence for a flattening of the relationship between NLR size and L 8 μm at the high-luminosity end, and propose that we are seeing a limiting NLR size of 10-20 kpc, beyond which the availability of gas to ionize becomes too low. We find that L_{[{O\\,{\\scriptsize {III}}}]} \\sim L_{8 \\,\\mu {m}}^{1.4}, consistent with a picture in which the L [O III] is dependent on the volume of the NLR. These results indicate that high-luminosity quasars have a strong effect in ionizing the available gas in a galaxy.

  11. A dust-obscured massive maximum-starburst galaxy at a redshift of 6.34.

    PubMed

    Riechers, Dominik A; Bradford, C M; Clements, D L; Dowell, C D; Pérez-Fournon, I; Ivison, R J; Bridge, C; Conley, A; Fu, Hai; Vieira, J D; Wardlow, J; Calanog, J; Cooray, A; Hurley, P; Neri, R; Kamenetzky, J; Aguirre, J E; Altieri, B; Arumugam, V; Benford, D J; Béthermin, M; Bock, J; Burgarella, D; Cabrera-Lavers, A; Chapman, S C; Cox, P; Dunlop, J S; Earle, L; Farrah, D; Ferrero, P; Franceschini, A; Gavazzi, R; Glenn, J; Solares, E A Gonzalez; Gurwell, M A; Halpern, M; Hatziminaoglou, E; Hyde, A; Ibar, E; Kovács, A; Krips, M; Lupu, R E; Maloney, P R; Martinez-Navajas, P; Matsuhara, H; Murphy, E J; Naylor, B J; Nguyen, H T; Oliver, S J; Omont, A; Page, M J; Petitpas, G; Rangwala, N; Roseboom, I G; Scott, D; Smith, A J; Staguhn, J G; Streblyanska, A; Thomson, A P; Valtchanov, I; Viero, M; Wang, L; Zemcov, M; Zmuidzinas, J

    2013-04-18

    Massive present-day early-type (elliptical and lenticular) galaxies probably gained the bulk of their stellar mass and heavy elements through intense, dust-enshrouded starbursts--that is, increased rates of star formation--in the most massive dark-matter haloes at early epochs. However, it remains unknown how soon after the Big Bang massive starburst progenitors exist. The measured redshift (z) distribution of dusty, massive starbursts has long been suspected to be biased low in z owing to selection effects, as confirmed by recent findings of systems with redshifts as high as ~5 (refs 2-4). Here we report the identification of a massive starburst galaxy at z = 6.34 through a submillimetre colour-selection technique. We unambiguously determined the redshift from a suite of molecular and atomic fine-structure cooling lines. These measurements reveal a hundred billion solar masses of highly excited, chemically evolved interstellar medium in this galaxy, which constitutes at least 40 per cent of the baryonic mass. A 'maximum starburst' converts the gas into stars at a rate more than 2,000 times that of the Milky Way, a rate among the highest observed at any epoch. Despite the overall downturn in cosmic star formation towards the highest redshifts, it seems that environments mature enough to form the most massive, intense starbursts existed at least as early as 880 million years after the Big Bang.

  12. A dust-obscured massive maximum-starburst galaxy at a redshift of 6.34.

    PubMed

    Riechers, Dominik A; Bradford, C M; Clements, D L; Dowell, C D; Pérez-Fournon, I; Ivison, R J; Bridge, C; Conley, A; Fu, Hai; Vieira, J D; Wardlow, J; Calanog, J; Cooray, A; Hurley, P; Neri, R; Kamenetzky, J; Aguirre, J E; Altieri, B; Arumugam, V; Benford, D J; Béthermin, M; Bock, J; Burgarella, D; Cabrera-Lavers, A; Chapman, S C; Cox, P; Dunlop, J S; Earle, L; Farrah, D; Ferrero, P; Franceschini, A; Gavazzi, R; Glenn, J; Solares, E A Gonzalez; Gurwell, M A; Halpern, M; Hatziminaoglou, E; Hyde, A; Ibar, E; Kovács, A; Krips, M; Lupu, R E; Maloney, P R; Martinez-Navajas, P; Matsuhara, H; Murphy, E J; Naylor, B J; Nguyen, H T; Oliver, S J; Omont, A; Page, M J; Petitpas, G; Rangwala, N; Roseboom, I G; Scott, D; Smith, A J; Staguhn, J G; Streblyanska, A; Thomson, A P; Valtchanov, I; Viero, M; Wang, L; Zemcov, M; Zmuidzinas, J

    2013-04-18

    Massive present-day early-type (elliptical and lenticular) galaxies probably gained the bulk of their stellar mass and heavy elements through intense, dust-enshrouded starbursts--that is, increased rates of star formation--in the most massive dark-matter haloes at early epochs. However, it remains unknown how soon after the Big Bang massive starburst progenitors exist. The measured redshift (z) distribution of dusty, massive starbursts has long been suspected to be biased low in z owing to selection effects, as confirmed by recent findings of systems with redshifts as high as ~5 (refs 2-4). Here we report the identification of a massive starburst galaxy at z = 6.34 through a submillimetre colour-selection technique. We unambiguously determined the redshift from a suite of molecular and atomic fine-structure cooling lines. These measurements reveal a hundred billion solar masses of highly excited, chemically evolved interstellar medium in this galaxy, which constitutes at least 40 per cent of the baryonic mass. A 'maximum starburst' converts the gas into stars at a rate more than 2,000 times that of the Milky Way, a rate among the highest observed at any epoch. Despite the overall downturn in cosmic star formation towards the highest redshifts, it seems that environments mature enough to form the most massive, intense starbursts existed at least as early as 880 million years after the Big Bang. PMID:23598341

  13. X-ray evidence of an obscured nucleus in the type 2 Seyfert galaxy Mkn3

    NASA Astrophysics Data System (ADS)

    Awaki, H.; Koyama, K.; Kunieda, H.; Tawara, Y.

    1990-08-01

    Seyfert galaxies are classified as type 1 or 2 according to the presence or absence of broad emission lines in the optical spectrum. The high velocities indicated by the broad lines in Seyfert 1 galaxies are taken to be good evidence of a compact, massive object, as are the strong and variable hard X-ray sources that are also generally observed in these objects. In contrast, Seyfert 2 galaxies possess neither of these characteristics, so the theory that they too have an accreting massive blackhole is less compelling. Since the discovery by spectropolarimetry of a 'hidden' Seyfert 1 nucleus in the prototypical Seyfert 2, NGC1068, the long-standing hope that the two classes may be unified has been revived. Here from observations by the Ginga satellite that another Seyfert 2, Mkn3, has the X-ray spectral signature of a hidden type 1 nucleus.

  14. A precessing molecular jet signaling an obscured, growing supermassive black hole in NGC 1377?

    NASA Astrophysics Data System (ADS)

    Aalto, S.; Costagliola, F.; Muller, S.; Sakamoto, K.; Gallagher, J. S.; Dasyra, K.; Wada, K.; Combes, F.; García-Burillo, S.; Kristensen, L. E.; Martín, S.; van der Werf, P.; Evans, A. S.; Kotilainen, J.

    2016-05-01

    With high resolution (0.̋25 × 0.̋18) ALMA CO 3-2 (345 GHz) observations of the nearby (D = 21 Mpc, 1'' = 102 pc), extremely radio-quiet galaxy NGC 1377, we have discovered a high-velocity, very collimated nuclear outflow which we interpret as a molecular jet with a projected length of ±150 pc. The launch region is unresolved and lies inside a radius r< 10 pc. Along the jet axis we find strong velocity reversals where the projected velocity swings from -150km s-1 to +150 km s-1. A simple model of a molecular jet precessing around an axis close to the plane of the sky can reproduce the observations. The velocity of the outflowing gas is difficult to constrain due to the velocity reversals but we estimate it to be between 240 and 850 km s-1 and the jet to precess with a period P = 0.3-1.1 Myr. The CO emission is clumpy along the jet and the total molecular mass in the high-velocity (±(60 to 150 km s-1)) gas lies between 2 × 106M⊙ (light jet) and 2 × 107M⊙ (massive jet). There is also CO emission extending along the minor axis of NGC 1377. It holds > 40% of the flux in NGC 1377 and may be a slower, wide-angle molecular outflow which is partially entrained by the molecular jet. We discuss the driving mechanism of the molecular jet and suggest that it is either powered by a (faint) radio jet or by an accretion disk-wind similar to those found towards protostars. It seems unlikely that a massive jet could have been driven out by the current level of nuclear activity which should then have undergone rapid quenching. The light jet would only have expelled 10% of the inner gas and may facilitate nuclear activity instead of suppressing it. The nucleus of NGC 1377 harbours intense embedded activity and we detect emission from vibrationally excited HCN J = 4-3ν2 = 1f which is consistent with hot gas and dust. We find large columns of H2 in the centre of NGC 1377 which may be a sign of a high rate of recent gas infall. The dynamical age ofthe molecular jet is short

  15. Infrared spectroscopy of Seyfert 2 galaxies: A look through the obscuring Torus?

    NASA Technical Reports Server (NTRS)

    Goodrich, Robert W.; Veilleux, Sylvain; Hill, Gary J.

    1994-01-01

    We present both high-resolution (R = 1260) and low-resolution (R = 345 and 425) J-band spectra of a sample of 15 Seyfert 2 galaxies. Our goal is to look for broad Pa beta lines, indicating broad-line regions which are hidden by dust from our view at optical wavelengths. Of the 15 objects studied here, three have broad Pa beta lines: MCG-05.23.16, Mrk 463E, and NGC 2992. Mrk 176 and NGC 5728 may also have weak broad lines. In NGC 5506, previously reported to have broad Pa beta and hydrogen alpha lines, we find that the Pa beta line profile is continuous and has the same shape as the nearby line (Fe II) lambda 1.2567, which should not have a broad component. We interpret these observations as gas from the narrow-line region (NLR) with no broad component. In NGC 5506, however, the NLR profiles become broader with increasing wavelength, indicating that highly reddened wings are becoming more readily visible at the longer wavelengths. We confirm the correlation of (O I) lambda 6300/hydrogen alpha and (Fe II) lambda 1.644/Br gamma (the latter transformed to (Fe II) lambda 1.2567/Pa beta to compare with our data) found by previous authors when comparing active galactic nuclei (AGNs), supernova remnants, starbursts, and H II regions. The correlation confirms that in all of these objects both (O I) lambda 6300 and the (Fe II) lines come from partially ionized regions in which hydrogen is mostly neutral. Comparison of the infrared optical depths with column depths determined from X-ray data show a general tendency for the objects with detected broad Pa beta to have lower X-ray columns.

  16. Particle-based labeling: Fast point-feature labeling without obscuring other visual features.

    PubMed

    Luboschik, Martin; Schumann, Heidrun; Cords, Hilko

    2008-01-01

    In many information visualization techniques, labels are an essential part to communicate the visualized data. To preserve the expressiveness of the visual representation, a placed label should neither occlude other labels nor visual representatives (e.g., icons, lines) that communicate crucial information. Optimal, non-overlapping labeling is an NP-hard problem. Thus, only a few approaches achieve a fast non-overlapping labeling in highly interactive scenarios like information visualization. These approaches generally target the point-feature label placement (PFLP) problem, solving only label-label conflicts. This paper presents a new, fast, solid and flexible 2D labeling approach for the PFLP problem that additionally respects other visual elements and the visual extent of labeled features. The results (number of placed labels, processing time) of our particle-based method compare favorably to those of existing techniques. Although the esthetic quality of non-real-time approaches may not be achieved with our method, it complies with practical demands and thus supports the interactive exploration of information spaces. In contrast to the known adjacent techniques, the flexibility of our technique enables labeling of dense point clouds by the use of non-occluding distant labels. Our approach is independent of the underlying visualization technique, which enables us to demonstrate the application of our labeling method within different information visualization scenarios.

  17. Hybridization among Arctic white-headed gulls (Larus spp.) obscures the genetic legacy of the Pleistocene

    USGS Publications Warehouse

    Sonsthagen, Sarah A.; Chesser, R. Terry; Bell, Douglas A.; Dove, Carla J.

    2012-01-01

    We studied the influence of glacial oscillations on the genetic structure of seven species of white-headed gull that breed at high latitudes (Larus argentatus, L. canus, L. glaucescens, L. glaucoides, L. hyperboreus, L. schistisagus, and L. thayeri). We evaluated localities hypothesized as ice-free areas or glacial refugia in other Arctic vertebrates using molecular data from 11 microsatellite loci, mitochondrial DNA (mtDNA) control region, and six nuclear introns for 32 populations across the Holarctic. Moderate levels of genetic structure were observed for microsatellites (FST= 0.129), introns (ΦST= 0.185), and mtDNA control region (ΦST= 0.461), with among-group variation maximized when populations were grouped based on subspecific classification. Two haplotype and at least two allele groups were observed across all loci. However, no haplotype/allele group was composed solely of individuals of a single species, a pattern consistent with recent divergence. Furthermore, northernmost populations were not well differentiated and among-group variation was maximized when L. argentatus and L. hyberboreus populations were grouped by locality rather than species, indicating recent hybridization. Four populations are located in putative Pleistocene glacial refugia and had larger t estimates than the other 28 populations. However, we were unable to substantiate these putative refugia using coalescent theory, as all populations had genetic signatures of stability based on mtDNA. The extent of haplotype and allele sharing among Arctic white-headed gull species is noteworthy. Studies of other Arctic taxa have generally revealed species-specific clusters as well as genetic structure within species, usually correlated with geography. Aspects of white-headed gull behavioral biology, such as colonization ability and propensity to hybridize, as well as their recent evolutionary history, have likely played a large role in the limited genetic structure observed.

  18. X-shooter reveals powerful outflows in z ˜ 1.5 X-ray selected obscured quasi-stellar objects

    NASA Astrophysics Data System (ADS)

    Brusa, M.; Bongiorno, A.; Cresci, G.; Perna, M.; Marconi, A.; Mainieri, V.; Maiolino, R.; Salvato, M.; Lusso, E.; Santini, P.; Comastri, A.; Fiore, F.; Gilli, R.; La Franca, F.; Lanzuisi, G.; Lutz, D.; Merloni, A.; Mignoli, M.; Onori, F.; Piconcelli, E.; Rosario, D.; Vignali, C.; Zamorani, G.

    2015-01-01

    We present X-shooter at Very Large Telescope observations of a sample of 10 luminous, X-ray obscured quasi-stellar objects (QSOs) at z ˜ 1.5 from the XMM-COSMOS survey, expected to be caught in the transitioning phase from starburst to active galactic nucleus (AGN)-dominated systems. The main selection criterion is X-ray detection at bright fluxes (LX ≳ 1044 erg s-1) coupled to red optical-to-near-infrared-to-mid-infrared colours. Thanks to its large wavelength coverage, X-shooter allowed us to determine accurate redshifts from the presence of multiple emission lines for five out of six targets for which we had only a photometric redshift estimate, with an 80 per cent success rate, significantly larger than what is observed in similar programs of spectroscopic follow-up of red QSOs. We report the detection of broad and shifted components in the [O III] λλ5007, 4959 complexes for six out of eight sources with these lines observable in regions free from strong atmospheric absorptions. The full width at half-maximum (FWHM) associated with the broad components are in the range FWHM ˜ 900-1600 km s-1, larger than the average value observed in Sloan Digital Sky Survey type 2 AGN samples at similar observed [O III] luminosity, but comparable to those observed for QSO/ultraluminous infrared galaxies systems for which the presence of kpc scale outflows has been revealed through integral field unit spectroscopy. Although the total outflow energetics (inferred under reasonable assumptions) may be consistent with winds accelerated by stellar processes, we favour an AGN origin for the outflows given the high outflow velocities observed (v > 1000 km s-1) and the presence of strong winds also in objects undetected in the far-infrared.

  19. Radio and Millimeter Properties of z~5.7 Lyα Emitters in the COSMOS Field: Limits on Radio AGNs, Submillimeter Galaxies, and Dust Obscuration

    NASA Astrophysics Data System (ADS)

    Carilli, C. L.; Murayama, T.; Wang, R.; Schinnerer, E.; Taniguchi, Y.; Smolčić, V.; Bertoldi, F.; Ajiki, M.; Nagao, T.; Sasaki, S. S.; Shioya, Y.; Aguirre, J. E.; Blain, A. W.; Scoville, N.; Sanders, D. B.

    2007-09-01

    We present observations at 1.4 and 250 GHz of the z~5.7 Lyα emitters (LAEs) in the COSMOS field found by Murayama et al. At 1.4 GHz there are 99 LAEs in the lower noise regions of the radio field. We do not detect any individual source down to 3 σ limits of ~30 μJy beam-1 at 1.4 GHz, nor do we detect a source in a stacking analysis, to a 2 σ limit of 2.5 μJy beam-1. At 250 GHz we do not detect any of the 10 LAEs that are located within the central regions of the COSMOS field covered by MAMBO (20'×20') to a typical 2 σ limit of S250<2 mJy. The radio data imply that there are no low-luminosity radio AGNs with L1.4>6×1024 W Hz-1 in the LAE sample. The radio and millimeter observations also rule out any highly obscured, extreme starbursts in the sample, i.e., any galaxies with massive star formation rates >1500 Msolar yr-1 in the full sample (based on the radio data), or 500 Msolar yr-1 for the 10% of the LAE sample that falls in the central MAMBO field. The stacking analysis implies an upper limit to the mean massive star formation rate of ~100 Msolar yr-1. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the National Radio Astronomy Observatory, which is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.; the IRAM 30 m telescope; and the Caltech Submillimeter Observatory.

  20. Gemini long-slit observations of luminous obscured quasars: Further evidence for an upper limit on the size of the narrow-line region

    SciTech Connect

    Hainline, Kevin N.; Hickox, Ryan C.; Greene, Jenny E.; Myers, Adam D.; Zakamska, Nadia L.; Liu, Guilin; Liu, Xin

    2014-05-20

    We examine the spatial extent of the narrow-line regions (NLRs) of a sample of 30 luminous obscured quasars at 0.4 < z < 0.7 observed with spatially resolved Gemini-N GMOS long-slit spectroscopy. Using the [O III] λ5007 emission feature, we estimate the size of the NLR using a cosmology-independent measurement: the radius where the surface brightness falls to 10{sup –15} erg s{sup –1} cm{sup –2} arcsec{sup –2}. We then explore the effects of atmospheric seeing on NLR size measurements and conclude that direct measurements of the NLR size from observed profiles are too large by 0.1-0.2 dex on average, as compared to measurements made to best-fit Sérsic or Voigt profiles convolved with the seeing. These data, which span a full order of magnitude in IR luminosity (log (L {sub 8} {sub μm}/erg s{sup –1}) = 44.4-45.4), also provide strong evidence that there is a flattening of the relationship between NLR size and active galactic nucleus luminosity at a seeing-corrected size of ∼7 kpc. The objects in this sample have high luminosities which place them in a previously under-explored portion of the size-luminosity relationship. These results support the existence of a maximal size of the NLR around luminous quasars; beyond this size, there is either not enough gas or the gas is over-ionized and does not produce enough [O III] λ5007 emission.

  1. New source and process apportionment method using a three-dimensional chemical transport model: Process, Age, and Source region Chasing ALgorithm (PASCAL)

    NASA Astrophysics Data System (ADS)

    Matsui, H.; Koike, M.

    2012-08-01

    We have developed a new source and process apportionment method, the Process, Age, and Source region Chasing ALgorithm (PASCAL), and implemented it in a three-dimensional chemical transport model, the Community Multiscale Air Quality (CMAQ) model. By adding new variables (tagged species), PASCAL traces 1) the source region of emissions (source apportionment), 2) the age of individual species (elapsed time from emissions), 3) net and gross production and loss amounts from individual physical and chemical processes during transport (Lagrangian way), and 4) local production and loss rates at individual grid cells (Eulerian way) for primary and secondary aerosols and their precursor gases. The main advantage of PASCAL is the third one, which can trace accumulated production and loss amounts of individual processes during transport from source regions to each grid cell (Lagrangian type of integration) for both gross (production and loss) and net (gross production - loss) concentrations. Currently the method is applied for mixing ratios of CO and SO2 and mass concentrations of black carbon and sulfate aerosols. This algorithm is not impacted by the non-linearity of chemical reactions and is computationally efficient. CMAQ/PASCAL model calculations were conducted over the East Asian region to test its performance. The overall validity of PASCAL calculations is confirmed for all species, periods, altitudes, and regions. This algorithm will be a useful tool in evaluating source regions as well as formation and loss processes of aerosols in the atmosphere in order to make effective strategies for emissions reduction.

  2. A randomized, double-blind trial of pegfilgrastim versus filgrastim for the management of neutropenia during CHASE(R) chemotherapy for malignant lymphoma.

    PubMed

    Kubo, Kohmei; Miyazaki, Yasuhiko; Murayama, Tohru; Shimazaki, Ryutaro; Usui, Noriko; Urabe, Akio; Hotta, Tomomitsu; Tamura, Kazuo

    2016-08-01

    Pegfilgrastim is a pegylated form of the granulocyte-colony stimulating factor, filgrastim. Herein, we report the results of a multicentre, randomized, double-blind phase III trial comparing the efficacy and safety of pegfilgrastim with filgrastim in patients with malignant lymphoma. Patients were randomized to receive either a single subcutaneous dose of pegfilgrastim or daily subcutaneous doses of filgrastim on day 4 after the completion of cyclophosphamide, cytarabine, etoposide and dexamethasone ± rituximab (CHASE(R); day 1-3) chemotherapy. The primary endpoint was the duration of severe neutropenia (DSN), defined as the number of days with neutrophil count <0·5 × 10(9) /l in the first cycle of chemotherapy. A total of 111 lymphoma patients were randomized to either the pegfilgrastim or filgrastim group. 109 patients received either pegfilgrastim (n = 54) or filgrastim (n = 55). Efficacy data were available for 107 patients (pegfilgrastim: n = 53, filgrastim: n = 54). Both groups were well balanced in terms of gender, age, performance status and other variables. The mean DSN (±S.D.) was 4·5 (±1·2) and 4·7 (±1·3) d in the pegfilgrastim and filgrastim groups. No significant difference in safety was observed. This trial verified the non-inferiority of a single subcutaneous dose of pegfilgrastim compared with daily subcutaneous doses of filgrastim, considering DSN as an indicator. PMID:27072050

  3. CLUSTERING OF OBSCURED AND UNOBSCURED QUASARS IN THE BOOeTES FIELD: PLACING RAPIDLY GROWING BLACK HOLES IN THE COSMIC WEB

    SciTech Connect

    Hickox, Ryan C.; Alexander, David M.; Goulding, Andrew D.; Myers, Adam D.; Brodwin, Mark; Forman, William R.; Jones, Christine; Murray, Stephen S.; Eisenstein, Daniel; Caldwell, Nelson; Brown, Michael J. I.; Cool, Richard J.; Kochanek, Christopher S.; Dey, Arjun; Jannuzi, Buell T.; Assef, Roberto J.; Eisenhardt, Peter R.; Gorjian, Varoujan; Stern, Daniel; Le Floc'h, Emeric

    2011-04-20

    We present the first measurement of the spatial clustering of mid-infrared-selected obscured and unobscured quasars, using a sample in the redshift range 0.7 < z < 1.8 selected from the 9 deg{sup 2} Booetes multiwavelength survey. Recently, the Spitzer Space Telescope and X-ray observations have revealed large populations of obscured quasars that have been inferred from models of the X-ray background and supermassive black hole evolution. To date, little is known about obscured quasar clustering, which allows us to measure the masses of their host dark matter halos and explore their role in the cosmic evolution of black holes and galaxies. In this study, we use a sample of 806 mid-infrared-selected quasars and {approx}250,000 galaxies to calculate the projected quasar-galaxy cross-correlation function w{sub p} (R). The observed clustering yields characteristic dark matter halo masses of log(M{sub halo} [h {sup -1} M{sub sun}]) = 12.7{sup +0.4}{sub -0.6} and 13.3{sup +0.3}{sub -0.4} for unobscured quasars (QSO-1s) and obscured quasars (Obs-QSOs), respectively. The results for QSO-1s are in excellent agreement with previous measurements for optically selected quasars, while we conclude that the Obs-QSOs are at least as strongly clustered as the QSO-1s. We test for the effects of photometric redshift errors on the optically faint Obs-QSOs, and find that our method yields a robust lower limit on the clustering; photo-z errors may cause us to underestimate the clustering amplitude of the Obs-QSOs by at most {approx}20%. We compare our results to previous studies, and speculate on physical implications of stronger clustering for obscured quasars.

  4. Complimentary Imaging Modalities for Investigating Obscure Gastrointestinal Bleeding: Capsule Endoscopy, Double-Balloon Enteroscopy, and Computed Tomographic Enterography.

    PubMed

    Chu, Ye; Wu, Sheng; Qian, Yuting; Wang, Qi; Li, Juanjuan; Tang, Yanping; Bai, Tingting; Wang, Lifu

    2016-01-01

    Objectives. The complimentary value of computed tomographic enterography (CTE) and double-balloon enteroscopy (DBE) combined with capsule endoscopy (CE) was evaluated in the diagnosis of obscure gastrointestinal bleeding (OGIB). Methods. Patients who received CE examinations at Ruijin Hospital between July 2007 and July 2014 with the indication of OGIB were identified, and those who also underwent DBE and/or CTE were included. Their clinical information was retrieved, and results from each test were compared with findings from the other two examinations. Results. The overall diagnostic yield of CE was comparable with DBE (73.9% versus 60.9%) but was significantly higher than the yield of CTE (87% versus 25%, p < 0.001). The diagnostic yield of angiodysplasia at CE was significantly higher than CTE (73% versus 8%, p < 0.001) and DBE (39.1% versus 17.4%, p = 0.013), while no significant difference was found between the three approaches for small bowel tumors. DBE and CTE identified small bowel diseases undetected or undetermined by CE. Conversely, CE improved diagnosis in the cases with negative CTE and DBE, and findings at initial CE directed further diagnosis made by DBE. Conclusions. Combination of the three diagnostic platforms provides complementary value in the diagnosis of OGIB. PMID:26858753

  5. Discovery of an obscured globular cluster associated with GX 354+0 /=4U/MXB 1728-34/

    NASA Astrophysics Data System (ADS)

    Grindlay, J. E.; Hertz, P.

    1981-07-01

    A diffuse infrared source identified as the most heavily obscured globular cluster yet found, was observed using the NASA 3m infrared telescope facility and Einstein positions for the X-ray source GX 354+0 (=4U/MXB 1728-34). Color excesses were measured to 1.4 + or - 0.3 for E(J-H) and 0.63 + or - 0.07 for E(H-K), and the visual extinction was determined at 10.6 + or - 1.3. The magnitude of several giant branch stars imply the cluster to be at a distance of 10.0 + or - 3.9 kpc, if metal rich, or 5.2 + or - 1.4 kpc, if metal poor. A single burst from MXB 1728-34 was observed with a blackbody temperature and cluster distance that indicated the luminosity to be not less than 10 times the Eddington limit for a neutron star model. This identification brings to 11 the number of compact X-ray sources in globular clusters, and reinforces the connection between GX sources, bursters, and globular clusters.

  6. SCATTERED X-RAYS IN OBSCURED ACTIVE GALACTIC NUCLEI AND THEIR IMPLICATIONS FOR GEOMETRICAL STRUCTURE AND EVOLUTION

    SciTech Connect

    Noguchi, Kazuhisa; Terashima, Yuichi; Awaki, Hisamitsu; Ishino, Yukiko; Ueda, Yoshihiro; Hashimoto, Yasuhiro; Koss, Michael

    2010-03-01

    We construct a new sample of 32 obscured active galactic nuclei (AGNs) selected from the Second XMM-Newton Serendipitous Source Catalogue to investigate their multiwavelength properties in relation to the 'scattering fraction', the ratio of the soft X-ray flux to the absorption-corrected direct emission. The sample covers a broad range of the scattering fraction ({approx}0.1%-10%). A quarter of the 32 AGNs have a very low scattering fraction (<= 0.5%), which suggests that they are buried in a geometrically thick torus with a very small opening angle. We investigate correlations between the scattering fraction and multiwavelength properties. We find that AGNs with a small scattering fraction tend to have low [O III]lambda5007/X-ray luminosity ratios. This result agrees with the expectation that the extent of the narrow-line region is small because of the small opening angle of the torus. There is no significant correlation between scattering fraction and far-infrared luminosity. This implies that a scale height of the torus is not primarily determined by starburst activity. We also compare scattering fraction with black hole mass or Eddington ratio and find a weak anti-correlation between the Eddington ratio and scattering fraction. This implies that more rapidly growing supermassive black holes tend to have thicker tori.

  7. White Hats Chasing Black Hats: Careers in IT and the Skills Required to Get There. Advisory from Professionals

    ERIC Educational Resources Information Center

    Fulton, Eric; Lawrence, Cameron; Clouse, Shawn

    2013-01-01

    The aim of this paper is to illuminate the exciting world in which "white hat crackers" operate and to suggest topics that can help prepare students to enter this high-demand field. While currently there is extraordinary demand for graduates to fill these positions that have relatively high starting salaries, employers find it difficult…

  8. Smog Obscures Chinese Coast

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Most of southeastern China has been covered by a thick greyish shroud of aerosol pollution over the last few weeks. The smog is so thick it is difficult to see the surface in some regions of this scene, acquired on January 7, 2002. The city of Hong Kong is the large brown cluster of pixels toward the lower lefthand corner of the image (indicated by the faint black box). The island of Taiwan, due east of mainland China, is also blanketed by the smog. This true-color image was captured by the Moderate-resolution Imaging Spectroradiometer (MODIS) sensor, flying aboard NASA's Terra satellite. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  9. Dust Obscures Korea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The dust cloud over eastern Asia was so thick on March 21, 2002, that the Korean Peninsula completely disappeared from view in this Sea-viewing Wide Field-of-view Sensor (SeaWiFS) image of the region. Parts of South Korea report that visibility at the surface is less than 50 m (165 feet). Airports throughout the region canceled flights due to the poor visibility. Eyewitnesses in China report that the dust was so thick in Beijing at times that visibility was limited to 100 m (330 feet), while in parts of the Gansu Province visibility was reported at less than 10 m (33 feet). Chinese officials say this is the worst dust storm to hit in more than 10 years. Dust from an earlier event still colors the air to the east of Japan. (The island of Honshu is just peeking out from under the cloud cover in these images.) Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  10. Mid-infrared luminous quasars in the GOODS-Herschel fields: a large population of heavily obscured, Compton-thick quasars at z ≈ 2

    NASA Astrophysics Data System (ADS)

    Del Moro, A.; Alexander, D. M.; Bauer, F. E.; Daddi, E.; Kocevski, D. D.; McIntosh, D. H.; Stanley, F.; Brandt, W. N.; Elbaz, D.; Harrison, C. M.; Luo, B.; Mullaney, J. R.; Xue, Y. Q.

    2016-02-01

    We present the infrared (IR) and X-ray properties of a sample of 33 mid-IR luminous quasars (νL6 μm ≥ 6 × 1044 erg s-1) at redshift z ≈ 1-3, identified through detailed spectral energy distribution analyses of distant star-forming galaxies, using the deepest IR data from Spitzer and Herschel in the GOODS-Herschel fields. The aim is to constrain the fraction of obscured, and Compton-thick (CT, NH > 1.5 × 1024 cm-2) quasars at the peak era of nuclear and star formation activities. Despite being very bright in the mid-IR band, ≈30 per cent of these quasars are not detected in the extremely deep 2 and 4 Ms Chandra X-ray data available in these fields. X-ray spectral analysis of the detected sources reveals that the majority (≈67 per cent) are obscured by column densities NH > 1022 cm-2; this fraction reaches ≈80 per cent when including the X-ray-undetected sources (9 out of 33), which are likely to be the most heavily obscured, CT quasars. We constrain the fraction of CT quasars in our sample to be ≈24-48 per cent, and their space density to be Φ = (6.7 ± 2.2) × 10-6 Mpc-3. From the investigation of the quasar host galaxies in terms of star formation rates (SFRs) and morphological distortions, as a sign of galaxy mergers/interactions, we do not find any direct relation between SFRs and quasar luminosity or X-ray obscuration. On the other hand, there is tentative evidence that the most heavily obscured quasars have, on average, more disturbed morphologies than the unobscured/moderately obscured quasar hosts, which preferentially live in undisturbed systems. However, the fraction of quasars with disturbed morphology amongst the whole sample is ≈40 per cent, suggesting that galaxy mergers are not the main fuelling mechanism of quasars at z ≈ 2.

  11. Historical collections reveal patterns of diffusion of sweet potato in Oceania obscured by modern plant movements and recombination.

    PubMed

    Roullier, Caroline; Benoit, Laure; McKey, Doyle B; Lebot, Vincent

    2013-02-01

    The history of sweet potato in the Pacific has long been an enigma. Archaeological, linguistic, and ethnobotanical data suggest that prehistoric human-mediated dispersal events contributed to the distribution in Oceania of this American domesticate. According to the "tripartite hypothesis," sweet potato was introduced into Oceania from South America in pre-Columbian times and was then later newly introduced, and diffused widely across the Pacific, by Europeans via two historically documented routes from Mexico and the Caribbean. Although sweet potato is the most convincing example of putative pre-Columbian connections between human occupants of Polynesia and South America, the search for genetic evidence of pre-Columbian dispersal of sweet potato into Oceania has been inconclusive. Our study attempts to fill this gap. Using complementary sets of markers (chloroplast and nuclear microsatellites) and both modern and herbarium samples, we test the tripartite hypothesis. Our results provide strong support for prehistoric transfer(s) of sweet potato from South America (Peru-Ecuador region) into Polynesia. Our results also document a temporal shift in the pattern of distribution of genetic variation in sweet potato in Oceania. Later reintroductions, accompanied by recombination between distinct sweet potato gene pools, have reshuffled the crop's initial genetic base, obscuring primary patterns of diffusion and, at the same time, giving rise to an impressive number of local variants. Moreover, our study shows that phenotypes, names, and neutral genes do not necessarily share completely parallel evolutionary histories. Multidisciplinary approaches, thus, appear necessary for accurate reconstruction of the intertwined histories of plants and humans.

  12. Urgent double balloon endoscopy provides higher yields than non-urgent double balloon endoscopy in overt obscure gastrointestinal bleeding

    PubMed Central

    Aniwan, Satimai; Viriyautsahakul, Vichai; Rerknimitr, Rungsun; Angsuwatcharakon, Phonthep; Kongkam, Pradermchai; Treeprasertsuk, Sombat; Kullavanijaya, Pinit

    2014-01-01

    Background and study aims: In overt obscure gastrointestinal bleeding (OV), double balloon endoscopy (DBE) is recommended as one of the most important investigations as it can provide both diagnosis and treatment. However, there is no set standard on the timing of DBE in OV. The aim of this study was to compare the diagnostic and therapeutic yields between urgent and non-urgent DBE in patients with OV. Patients and methods: Between January 2006 and February 2013, 120 patients with OV who underwent DBE were retrospectively reviewed. An urgent DBE was defined as DBE performed within 72 h from the last visible gastrointestinal bleeding (n = 74) whereas a non-urgent DBE was defined as DBE performed after 72 h (n = 46). Diagnostic yields, therapeutic impact and clinical outcomes were evaluated. Results: Diagnostic yield in urgent DBE was significantly higher than that in non-urgent DBE (70 % versus 30 %; P < 0.05). Urgent DBE offered significantly more therapies including endoscopic, angiographic embolization, and surgery than non-urgent DBE (54 % versus 15 %; P < 0.001). Endoscopic therapy was performed in 43 % of urgent-DBE patients whereas only 13 % of patients in the other group received endoscopic therapy (P < 0.01). In patients with identified bleeding sources, the rebleeding rate was lower in patients who underwent urgent DBE than in those who underwent non-urgent DBE (10 % versus 29 %, NS). Conclusions: Regarding diagnostic and therapeutic impacts in OV, our retrospective study showed that urgent DBE is better than non-urgent DBE. The recurrent bleeding rate in patients undergoing urgent DBE tended to be lower. PMID:26135267

  13. The relationship between cell proliferation and differentiation and mapping of putative dental pulp stem/progenitor cells during mouse molar development by chasing BrdU-labeling.

    PubMed

    Ishikawa, Yuko; Ida-Yonemochi, Hiroko; Nakakura-Ohshima, Kuniko; Ohshima, Hayato

    2012-04-01

    Human dental pulp contains adult stem cells. Our recent study demonstrated the localization of putative dental pulp stem/progenitor cells in the rat developing molar by chasing 5-bromo-2'-deoxyuridine (BrdU)-labeling. However, there are no available data on the localization of putative dental pulp stem/progenitor cells in the mouse molar. This study focuses on the mapping of putative dental pulp stem/progenitor cells in addition to the relationship between cell proliferation and differentiation in the developing molar using BrdU-labeling. Numerous proliferating cells appeared in the tooth germ and the most active cell proliferation in the mesenchymal cells occurred in the prenatal stages, especially on embryonic Day 15 (E15). Cell proliferation in the pulp tissue dramatically decreased in number by postnatal Day 3 (P3) when nestin-positive odontoblasts were arranged in the cusped areas and disappeared after postnatal Week 1 (P1W). Root dental papilla included numerous proliferating cells during P5 to P2W. Three to four intraperitoneal injections of BrdU were given to pregnant ICR mice and revealed slow-cycling long-term label-retaining cells (LRCs) in the mature tissues of postnatal animals. Numerous dense LRCs postnatally decreased in number and reached a plateau after P1W when they mainly resided in the center of the dental pulp, associating with blood vessels. Furthermore, numerous dense LRCs co-expressed mesenchymal stem cell markers such as STRO-1 and CD146. Thus, dense LRCs in mature pulp tissues were believed to be dental pulp stem/progenitor cells harboring in the perivascular niche surrounding the endothelium.

  14. A comparative study of the response to repeated chasing stress in Atlantic salmon (Salmo salar L.) parr and post-smolts.

    PubMed

    Madaro, Angelico; Olsen, Rolf Erik; Kristiansen, Tore S; Ebbesson, Lars O E; Flik, Gert; Gorissen, Marnix

    2016-02-01

    When Atlantic salmon parr migrate from fresh water towards the sea, they undergo extensive morphological, neural, physiological and behavioural changes. Such changes have the potential to affect their responsiveness to various environmental factors that impose stress. In this study we compared the stress responses in parr and post-smolt salmon following exposure to repeated chasing stress (RCS) for three weeks. At the end of this period, all fish were challenged with a novel stressor and sampled before (T0) and after 1h (T1). Parr had a higher growth rate than post-smolts. Plasma cortisol declined in the RCS groups within the first week suggesting a rapid habituation/desensitisation of the endocrine stress axis. As a result of the desensitised HPI axis, RCS groups showed a reduced cortisol response when exposed to the novel stressor. In preoptic area (POA) crf mRNA levels were higher in all post-smolt groups compared to parr. 11βhsd2 decreased by RCS and by the novel stressor in post-smolt controls (T1), whereas no effect of either stress was seen in parr. The grs were low in all groups except for parr controls. In pituitary, parr controls had higher levels of crf1r mRNA than the other parr and post-smolt groups, whilst pomcb was higher in post-smolt control groups. Overall, 11βhsd2 transcript abundance in parr was lower than post-smolt groups; after the novel stressor pomcs, grs and mr were up-regulated in parr control (T1). In summary, we highlight differences in the central stress response between parr and post-smolt salmon following RCS. PMID:26549876

  15. A comparative study of the response to repeated chasing stress in Atlantic salmon (Salmo salar L.) parr and post-smolts.

    PubMed

    Madaro, Angelico; Olsen, Rolf Erik; Kristiansen, Tore S; Ebbesson, Lars O E; Flik, Gert; Gorissen, Marnix

    2016-02-01

    When Atlantic salmon parr migrate from fresh water towards the sea, they undergo extensive morphological, neural, physiological and behavioural changes. Such changes have the potential to affect their responsiveness to various environmental factors that impose stress. In this study we compared the stress responses in parr and post-smolt salmon following exposure to repeated chasing stress (RCS) for three weeks. At the end of this period, all fish were challenged with a novel stressor and sampled before (T0) and after 1h (T1). Parr had a higher growth rate than post-smolts. Plasma cortisol declined in the RCS groups within the first week suggesting a rapid habituation/desensitisation of the endocrine stress axis. As a result of the desensitised HPI axis, RCS groups showed a reduced cortisol response when exposed to the novel stressor. In preoptic area (POA) crf mRNA levels were higher in all post-smolt groups compared to parr. 11βhsd2 decreased by RCS and by the novel stressor in post-smolt controls (T1), whereas no effect of either stress was seen in parr. The grs were low in all groups except for parr controls. In pituitary, parr controls had higher levels of crf1r mRNA than the other parr and post-smolt groups, whilst pomcb was higher in post-smolt control groups. Overall, 11βhsd2 transcript abundance in parr was lower than post-smolt groups; after the novel stressor pomcs, grs and mr were up-regulated in parr control (T1). In summary, we highlight differences in the central stress response between parr and post-smolt salmon following RCS.

  16. A Novel Pulse-Chase SILAC Strategy Measures Changes in Protein Decay and Synthesis Rates Induced by Perturbation of Proteostasis with an Hsp90 Inhibitor

    PubMed Central

    Fierro-Monti, Ivo; Racle, Julien; Hernandez, Celine; Waridel, Patrice; Hatzimanikatis, Vassily; Quadroni, Manfredo

    2013-01-01

    Standard proteomics methods allow the relative quantitation of levels of thousands of proteins in two or more samples. While such methods are invaluable for defining the variations in protein concentrations which follow the perturbation of a biological system, they do not offer information on the mechanisms underlying such changes. Expanding on previous work [1], we developed a pulse-chase (pc) variant of SILAC (stable isotope labeling by amino acids in cell culture). pcSILAC can quantitate in one experiment and for two conditions the relative levels of proteins newly synthesized in a given time as well as the relative levels of remaining preexisting proteins. We validated the method studying the drug-mediated inhibition of the Hsp90 molecular chaperone, which is known to lead to increased synthesis of stress response proteins as well as the increased decay of Hsp90 “clients”. We showed that pcSILAC can give information on changes in global cellular proteostasis induced by treatment with the inhibitor, which are normally not captured by standard relative quantitation techniques. Furthermore, we have developed a mathematical model and computational framework that uses pcSILAC data to determine degradation constants kd and synthesis rates Vs for proteins in both control and drug-treated cells. The results show that Hsp90 inhibition induced a generalized slowdown of protein synthesis and an increase in protein decay. Treatment with the inhibitor also resulted in widespread protein-specific changes in relative synthesis rates, together with variations in protein decay rates. The latter were more restricted to individual proteins or protein families than the variations in synthesis. Our results establish pcSILAC as a viable workflow for the mechanistic dissection of changes in the proteome which follow perturbations. Data are available via ProteomeXchange with identifier PXD000538. PMID:24312217

  17. SALT LONG-SLIT SPECTROSCOPY OF LUMINOUS OBSCURED QUASARS: AN UPPER LIMIT ON THE SIZE OF THE NARROW-LINE REGION?

    SciTech Connect

    Hainline, Kevin N.; Hickox, Ryan; Greene, Jenny E.; Myers, Adam D.; Zakamska, Nadia L.

    2013-09-10

    We present spatially resolved long-slit spectroscopy from the Southern African Large Telescope to examine the spatial extent of the narrow-line regions (NLRs) of a sample of eight luminous obscured quasars at 0.10 < z < 0.43. Our results are consistent with an observed shallow slope in the relationship between NLR size and L{sub [OIII]}, which has been interpreted to indicate that NLR size is limited by the density and ionization state of the NLR gas rather than the availability of ionizing photons. We also explore how the NLR size scales with a more direct measure of instantaneous active galactic nucleus power using mid-IR photometry from the Wide Field Infrared Explorer, which probes warm to hot dust near the central black hole and so, unlike [O III], does not depend on the properties of the NLR. Using our results as well as samples from the literature, we obtain a power-law relationship between NLR size and L{sub 8{mu}m} that is significantly steeper than that observed for NLR size and L{sub [OIII]}. We find that the size of the NLR goes approximately as L{sup 1/2}{sub 8{mu}m}, as expected from the simple scenario of constant-density clouds illuminated by a central ionizing source. We further see tentative evidence for a flattening of the relationship between NLR size and L{sub 8{mu}m} at the high-luminosity end, and propose that we are seeing a limiting NLR size of 10-20 kpc, beyond which the availability of gas to ionize becomes too low. We find that L{sub [OIII]}{approx}L{sub 8{mu}m}{sup 1.4}, consistent with a picture in which the L{sub [OIII]} is dependent on the volume of the NLR. These results indicate that high-luminosity quasars have a strong effect in ionizing the available gas in a galaxy.

  18. CENSUS OF SELF-OBSCURED MASSIVE STARS IN NEARBY GALAXIES WITH SPITZER: IMPLICATIONS FOR UNDERSTANDING THE PROGENITORS OF SN 2008S-LIKE TRANSIENTS

    SciTech Connect

    Khan, Rubab; Stanek, K. Z.; Kochanek, C. S.; Thompson, Todd A.; Beacom, J. F.; Prieto, J. L. E-mail: kstanek@astronomy.ohio-state.ed E-mail: thompson@astronomy.ohio-state.ed E-mail: beacom@mps.ohio-state.ed

    2010-06-01

    A new link in the causal mapping between massive stars and potentially fatal explosive transients opened with the 2008 discovery of the dust-obscured progenitors of the luminous outbursts in NGC 6946 and NGC 300. Here, we carry out a systematic mid-IR photometric search for massive, luminous, and self-obscured stars in four nearby galaxies: M33, NGC 300, M81, and NGC 6946. For detection, we use only the 3.6 {mu}m and 4.5 {mu}m IRAC bands, as these can still be used for multi-epoch Spitzer surveys of nearby galaxies ({approx}<10 Mpc). We combine familiar point-spread function and aperture photometry with an innovative application of image subtraction to catalog the self-obscured massive stars in these galaxies. In particular, we verify that stars analogous to the progenitors of the NGC 6946 (SN 2008S) and NGC 300 transients are truly rare in all four galaxies: their number may be as low as {approx}1 per galaxy at any given moment. This result empirically supports the idea that the dust-enshrouded phase is a very short lived phenomenon in the lives of many massive stars and that these objects constitute a natural extension of the asymptotic giant branch sequence. We also provide mid-IR catalogs of sources in NGC 300, M81, and NGC 6946.

  19. Hyper-luminous dust-obscured galaxies discovered by the Hyper Suprime-Cam on Subaru and WISE

    NASA Astrophysics Data System (ADS)

    Toba, Yoshiki; Nagao, Tohru; Strauss, Michael A.; Aoki, Kentaro; Goto, Tomotsugu; Imanishi, Masatoshi; Kawaguchi, Toshihiro; Terashima, Yuichi; Ueda, Yoshihiro; Bosch, James; Bundy, Kevin; Doi, Yoshiyuki; Inami, Hanae; Komiyama, Yutaka; Lupton, Robert H.; Matsuhara, Hideo; Matsuoka, Yoshiki; Miyazaki, Satoshi; Morokuma, Tomoki; Nakata, Fumiaki; Oi, Nagisa; Onoue, Masafusa; Oyabu, Shinki; Price, Paul; Tait, Philip J.; Takata, Tadafumi; Tanaka, Manobu M.; Terai, Tsuyoshi; Turner, Edwin L.; Uchida, Tomohisa; Usuda, Tomonori; Utsumi, Yousuke; Yamada, Yoshihiko; Wang, Shiang-Yu

    2015-10-01

    We present the photometric properties of a sample of infrared (IR) bright dust-obscured galaxies (DOGs). Combining wide and deep optical images obtained with the Hyper Suprime-Cam on the Subaru Telescope and all-sky mid-IR (MIR) images taken with Wide-Field Infrared Survey Explorer, we discovered 48 DOGs with i - Ks > 1.2 and i - [22] > 7.0, where i, Ks, and [22] represent AB magnitude in the i-band, Ks-band, and 22 μm, respectively, in the GAMA 14 hr field (˜ 9 deg2). Among these objects, 31 (˜ 65%) show power-law spectral energy distributions (SEDs) in the near-IR (NIR) and MIR regime, while the remainder show an NIR bump in their SEDs. Assuming that the redshift distribution for our DOGs sample is Gaussian, with mean and sigma z = 1.99 ± 0.45, we calculated their total IR luminosity using an empirical relation between 22 μm luminosity and total IR luminosity. The average value of the total IR luminosity is (3.5 ± 1.1) × 1013 L⊙, which classifies them as hyper-luminous infrared galaxies. We also derived the total IR luminosity function (LF) and IR luminosity density (LD) for a flux-limited subsample of 18 DOGs with 22 μm flux greater than 3.0 mJy and with i-band magnitude brighter than 24 AB magnitude. The derived space density for this subsample is log φ = -6.59 ± 0.11 [Mpc-3]. The IR LF for DOGs including data obtained from the literature is fitted well by a double-power law. The derived lower limit for the IR LD for our sample is ρIR ˜ 3.8 × 107 [L⊙ Mpc-3] and its contributions to the total IR LD, IR LD of all ultra-luminous infrared galaxies, and that of all DOGs are > 3%, > 9%, and > 15%, respectively.

  20. Comparison of irrigation pumpage with change in ground-water storage in the High Plains aquifer in Chase, Dundy, and Perkins counties, Nebraska, 1975-83

    USGS Publications Warehouse

    Heimes, F.J.; Ferrigno, C.F.; Gutentag, E.D.; Lucky, R.R.; Stephens, D.M.; Weeks, J.B.

    1987-01-01

    The relation between pumpage and change in storage was evaluated for most of a three-county area in southwestern Nebraska from 1975 through 1983. Initial comparison of the 1975-83 pumpage with change in storage in the study area indicated that the 1 ,042,300 acre-ft of change in storage was only about 30% of the 3,425,000 acre-ft of pumpage. An evaluation of the data used to calculate pumpage and change in storage indicated that there was a relatively large potential for error in estimates of specific yield. As a result, minimum and maximum values of specific yield were estimated and used to recalculate change in storage. Estimates also were derived for the minimum and maximum amounts of recharge that could occur as a result of cultivation practices. The minimum and maximum estimates for specific yield and for recharge from cultivation practices were used to compute a range of values for the potential amount of additional recharge that occurred as a result of irrigation. The minimum and maximum amounts of recharge that could be caused by irrigation in the study area were 953,200 acre-ft (28% of pumpage) and 2,611,200 acre-ft (76% of pumpage), respectively. These values indicate that a substantial percentage of the water pumped from the aquifer is resupplied to storage in the aquifer as a result of a combination of irrigation return flow and enhanced recharge from precipitation that results from cultivation and irrigation practices. (Author 's abstract)

  1. How low does iron go? Chasing the active species in fe-catalyzed cross-coupling reactions.

    PubMed

    Bedford, Robin B

    2015-05-19

    The catalytic cross-coupling reactions of organic halides or related substrates with organometallic nucleophiles form the cornerstone of many carbon-carbon bond-forming processes. While palladium-based catalysts typically mediate such reactions, there are increasing concerns about the long-term sustainability of palladium in synthesis. This is due to the high cost of palladium, coupled with its low natural abundance, environmentally deleterious extraction (∼6 g of metal are produced per ton of ore), toxicity, and competition for its use from the automotive and consumer electronics sectors. Therefore, there is a growing interest in replacing palladium-based catalysts with those incorporating more earth-abundant elements. With its low cost, high natural abundance, and low toxicity, iron makes a particularly appealing alternative, and accordingly, the development of iron-catalyzed cross-coupling is undergoing explosive growth. However, our understanding of the mechanisms that underpin the iron-based catalytic cycles is still very much in its infancy. Mechanistic insight into catalytic reactions is not only academically important but also allows us to maximize the efficiency of processes or even to develop entirely new transformations. Key to the development of robust mechanistic models for cross-coupling is knowing the lowest oxidation state in the cycle. Once this is established, we can explore subsequent redox processes and build the catalytic manifold. Until we know with confidence what the lowest oxidation state is, any cycles proposed are largely just guesswork. To date, Fe(-II), Fe(-I), Fe(0), Fe(I), and Fe(II) have been proposed as contenders for the lowest-oxidation-state species in the cycle in iron-catalyzed cross-coupling; the aim of this Account is to pull together the various pieces of evidence in support, or otherwise, of each of these suggestions in turn. There currently exists no direct evidence that oxidation states below Fe(0) are active in the

  2. How low does iron go? Chasing the active species in fe-catalyzed cross-coupling reactions.

    PubMed

    Bedford, Robin B

    2015-05-19

    The catalytic cross-coupling reactions of organic halides or related substrates with organometallic nucleophiles form the cornerstone of many carbon-carbon bond-forming processes. While palladium-based catalysts typically mediate such reactions, there are increasing concerns about the long-term sustainability of palladium in synthesis. This is due to the high cost of palladium, coupled with its low natural abundance, environmentally deleterious extraction (∼6 g of metal are produced per ton of ore), toxicity, and competition for its use from the automotive and consumer electronics sectors. Therefore, there is a growing interest in replacing palladium-based catalysts with those incorporating more earth-abundant elements. With its low cost, high natural abundance, and low toxicity, iron makes a particularly appealing alternative, and accordingly, the development of iron-catalyzed cross-coupling is undergoing explosive growth. However, our understanding of the mechanisms that underpin the iron-based catalytic cycles is still very much in its infancy. Mechanistic insight into catalytic reactions is not only academically important but also allows us to maximize the efficiency of processes or even to develop entirely new transformations. Key to the development of robust mechanistic models for cross-coupling is knowing the lowest oxidation state in the cycle. Once this is established, we can explore subsequent redox processes and build the catalytic manifold. Until we know with confidence what the lowest oxidation state is, any cycles proposed are largely just guesswork. To date, Fe(-II), Fe(-I), Fe(0), Fe(I), and Fe(II) have been proposed as contenders for the lowest-oxidation-state species in the cycle in iron-catalyzed cross-coupling; the aim of this Account is to pull together the various pieces of evidence in support, or otherwise, of each of these suggestions in turn. There currently exists no direct evidence that oxidation states below Fe(0) are active in the

  3. A study on a robot chasing a human using Kinect while identifying walking parameters using the back view

    NASA Astrophysics Data System (ADS)

    Konno, S.; Mita, A.

    2014-03-01

    Recently, the demand of the building spaces to respond to increase of single aged households and the diversification of life style is increasing. Smart house is one of them, but it is difficult for them to be changed and renovated. Therefore, we suggest Biofied builing. In biofied building, we use a mobile robot to get concious and unconcious information about residents and try to make it more secure and comfort builing spaces by realizing the intraction between residents and builing spaces. Walking parameters are one of the most important unconscious information about residents. They are an indicator of autonomy of elderly, and changes of stride length and walking speed may be pridictive of a future fall and a cognitive impairment. By observing their walking and informing residents their walking state, they can forestall such dangers and it helps them to live more securely and autonomously. Many methods to estimate walking parameters have been studied. The famous ones are to use accelerometers and a motion capture camera. Walking parameters estimated by them are high precise but the sensors are attached to a human body in these method and it can make human's walk different from the original walk. Furthermore, some elderly feel it to invade them. In this work, Kinect which can get information about human untouchably was used on the mobile robot. A stride time, stride length, and walking speed were estimated from the back view of human by following him or her. Evaluation was done for 10m, 5m, 4m, and 3m in whole walking. As a result, the proposal system can estimate walking parameters of the walk more than 3m.

  4. Dusty Quasars at High Redshifts

    NASA Astrophysics Data System (ADS)

    Weedman, Daniel; Sargsyan, Lusine

    2016-09-01

    A population of quasars at z ˜ 2 is determined based on dust luminosities νL ν (7.8 μm) that includes unobscured, partially obscured, and obscured quasars. Quasars are classified by the ratio νL ν (0.25 μm)/νL ν (7.8 μm) = UV/IR, assumed to measure obscuration of UV luminosity by the dust that produces IR luminosity. Quasar counts at rest-frame 7.8 μm are determined for quasars in the Boötes field of the NOAO Deep Wide Field Survey using 24 μm sources with optical redshifts from the AGN and Galaxy Evolution Survey (AGES) or infrared redshifts from the Spitzer Infrared Spectrograph. Spectral energy distributions are extended to far-infrared wavelengths using observations from the Herschel Space Observatory Spectral and Photometric Imaging Receiver (SPIRE), and new SPIRE photometry is presented for 77 high-redshift quasars from the Sloan Digital Sky Survey. It is found that unobscured and obscured quasars have similar space densities at rest-frame 7.8 μm, but the ratio L ν (100 μm)/L ν (7.8 μm) is about three times higher for obscured quasars than for unobscured, so that far-infrared or submillimeter quasar detections are dominated by obscured quasars. We find that only ˜5% of high-redshift submillimeter sources are quasars and that existing 850 μm surveys or 2 mm surveys should already have detected sources at z ˜ 10 if quasar and starburst luminosity functions remain the same from z = 2 until z = 10.

  5. Extrapolating Ground-Based Aircraft Engine Exhaust Emissions to Cruise Conditions: Lessons From the 2013 ACCESS Chase Plane Experiment

    NASA Astrophysics Data System (ADS)

    Moore, R.; Shook, M.; Thornhill, K. L.; Winstead, E.; Anderson, B. E.

    2011-12-01

    Aircraft engine emissions constitute a tiny fraction of the global black carbon mass, but can have a disproportionate climatic impact because they are emitted high in the troposphere and in remote regions with otherwise low aerosol concentrations. Consequently, these particles are likely to strongly influence cirrus and contrail formation by acting as ice nuclei (IN). However, the ice nucleating properties of aircraft exhaust at relevant atmospheric conditions are not well known, and thus, the overall impact of aviation on cloud formation remains very uncertain. While a number of aircraft engine emissions studies have previously been conducted at sea level temperature and pressure (e.g., APEX, AAFEX-1 and 2), it unclear the extent to which exhaust emissions on the ground translate to emissions at cruise conditions with much lower inlet gas temperatures and pressures. To address this need, the NASA Alternative Fuel Effects on Contrails and Cruise Emissions (ACCESS) was conducted in February-April, 2013 to examine the aerosol and gas emissions from the NASA DC-8 under a variety of different fuel types, engine power, and altitude/meteorological conditions. Two different fuel types were studied: a traditional JP-8 fuel and a 50:50 blend of JP-8 and a camelina-based hydro-treated renewable jet (HRJ) fuel. Emissions were sampled using a comprehensive suite of gas- and aerosol-phase instrumentation integrated on an HU-25 Falcon jet that was positioned in the DC-8 exhaust plume at approximately 100-500m distance behind the engines. In addition, a four-hour ground test was carried out with sample probes positioned at 30 m behind each of the inboard engines. Measurements of aerosol concentration, size distribution, soot mass, and hygroscopicity were carried out along with trace gas measurements of CO2, NO, NO2, O3, and water vapor. NOx emissions were reconciled by employing the well-established Boeing method for normalizing engine fuel flow rates to STP; however, comparison

  6. Extrapolating Ground-Based Aircraft Engine Exhaust Emissions to Cruise Conditions: Lessons From the 2013 ACCESS Chase Plane Experiment

    NASA Astrophysics Data System (ADS)

    Moore, R.; Shook, M.; Thornhill, K. L.; Winstead, E.; Anderson, B. E.

    2013-12-01

    Aircraft engine emissions constitute a tiny fraction of the global black carbon mass, but can have a disproportionate climatic impact because they are emitted high in the troposphere and in remote regions with otherwise low aerosol concentrations. Consequently, these particles are likely to strongly influence cirrus and contrail formation by acting as ice nuclei (IN). However, the ice nucleating properties of aircraft exhaust at relevant atmospheric conditions are not well known, and thus, the overall impact of aviation on cloud formation remains very uncertain. While a number of aircraft engine emissions studies have previously been conducted at sea level temperature and pressure (e.g., APEX, AAFEX-1 and 2), it unclear the extent to which exhaust emissions on the ground translate to emissions at cruise conditions with much lower inlet gas temperatures and pressures. To address this need, the NASA Alternative Fuel Effects on Contrails and Cruise Emissions (ACCESS) was conducted in February-April, 2013 to examine the aerosol and gas emissions from the NASA DC-8 under a variety of different fuel types, engine power, and altitude/meteorological conditions. Two different fuel types were studied: a traditional JP-8 fuel and a 50:50 blend of JP-8 and a camelina-based hydro-treated renewable jet (HRJ) fuel. Emissions were sampled using a comprehensive suite of gas- and aerosol-phase instrumentation integrated on an HU-25 Falcon jet that was positioned in the DC-8 exhaust plume at approximately 100-500m distance behind the engines. In addition, a four-hour ground test was carried out with sample probes positioned at 30 m behind each of the inboard engines. Measurements of aerosol concentration, size distribution, soot mass, and hygroscopicity were carried out along with trace gas measurements of CO2, NO, NO2, O3, and water vapor. NOx emissions were reconciled by employing the well-established Boeing method for normalizing engine fuel flow rates to STP; however, comparison

  7. Does the time of the sampling matter in 13C pulse labeling and chasing experiments? A case study on beech seedlings

    NASA Astrophysics Data System (ADS)

    Gavrichkova, Olga; Thoms, Ronny; Muhr, Jan; Karlowsky, Stefan; Keitel, Claudia; Kayler, Zachary; Calfapietra, Carlo; Gessler, Arthur; Brugnoli, Enrico; Gleixner, Gerd

    2016-04-01

    13C pulse labeling and chasing is a valuable and very popular tool for determination of the fate and turnover rates of C in plant-soil systems. Continuous isoflux measurements became an accessible reality allowing to cover completely the diurnal variation in label assimilation and respiration fluxes. Label turnover in multiple pools, especially of those located belowground, is more often assessed instead by isolated day-time samplings. By increasing the sampling frequency of belowground compartments we aimed to catch the short-term diurnal variations in label allocation and to link these processes with label dynamics in the aboveground biomass. For these purposes we labeled 3-m height soil-grown European beech seedlings with 13C enriched CO2 and traced the flow of 13C within belowground plant-soil continuum. Continuous soil isoflux measurements were accompanied by a 3-h-frequency sampling of root and soil material during the first 48 h, followed by a daily sampling in the successive 5 days. The amount of label found in microbial biomass depended partially on the amount of roots in the sample. Microbial biomass C (MBC) and microbial respiration showed very strong correlation, suggesting the possibility to use one as a proxy of the other. MBC enrichment showed a clear diurnal pattern with night-time and early morning peaks. These peaks were similar in shape and shifted by one sampling when compared to root sugars enrichment. Soil respiration showed instead a single bell-shape peak in 13C, likely due to a sequence of peaks of root and microbial origin. 13C flow into soil microbial functional groups was assessed less frequently through phospholipid fatty acid analyses (PLFA). The microorganisms were separated into two distinct groups by the time of the appearance of the label in the single PLFAs. The first group was characterized by a fast appearance of the label and higher enrichment and was composed of Gram negative bacteria and saprotrophic fungi likely living in

  8. Five-year Results of Whole Breast Intensity Modulated Radiation Therapy for the Treatment of Early Stage Breast Cancer: The Fox Chase Cancer Center Experience

    SciTech Connect

    Keller, Lanea M.M.; Sopka, Dennis M.; Li Tianyu; Klayton, Tracy; Li Jinsheng; Anderson, Penny R.; Bleicher, Richard J.; Sigurdson, Elin R.; Freedman, Gary M.

    2012-11-15

    Purpose: To report the 5-year outcomes using whole-breast intensity-modulated radiation therapy (IMRT) for the treatment of early-stage-breast cancer at the Fox Chase Cancer Center. Methods and Materials: A total of 946 women with early-stage breast cancer (stage 0, I, or II) were treated with IMRT after surgery with or without systemic therapy from 2003-2010. Whole-breast radiation was delivered via an IMRT technique with a median whole-breast radiation dose of 46 Gy and median tumor bed boost of 14 Gy. Endpoints included local-regional recurrence, cosmesis, and late complications. Results: With a median follow-up of 31 months (range, 1-97 months), there were 12 ipsilateral breast tumor recurrences (IBTR) and one locoregional recurrence. The 5-year actuarial IBTR and locoregional recurrence rates were 2.0% and 2.4%. Physician-reported cosmestic outcomes were available for 645 patients: 63% were considered 'excellent', 33% 'good', and <1.5% 'fair/poor'. For physician-reported cosmesis, boost doses {>=}16 Gy, breast size >900 cc, or boost volumes >34 cc were significantly associated with a 'fair/poor' cosmetic outcome. Fibrosis, edema, erythema, and telangectasia were also associated with 'fair/poor' physician-reported cosmesis; erythema and telangectasia remained significant on multivariate analysis. Patient-reported cosmesis was available for 548 patients, and 33%, 50%, and 17% of patients reported 'excellent', 'good', and 'fair/poor' cosmesis, respectively. The use of a boost and increased boost volume: breast volume ratio were significantly associated with 'fair/poor' outcomes. No parameter for patient-reported cosmesis was significant on multivariate analysis. The chances of experiencing a treatment related effect was significantly associated with a boost dose {>=}16 Gy, receipt of chemotherapy and endocrine therapy, large breast size, and electron boost energy. Conclusions: Whole-breast IMRT is associated with very low rates of local recurrence at 5 years, 83

  9. Chasing White-Light Flares

    NASA Astrophysics Data System (ADS)

    Hudson, H. S.

    2016-05-01

    In this memoir I describe my life in research, mostly in the area of solar physics. The recurring theme is "white-light flares," and several sections of this paper deal with this and related phenomena; I wind up describing how I see the state of the art in this still-interesting and crucially important (as it has been since 1859) area of flare research. I also describe my participation in two long-lived satellite programs dedicated to solar observations ( Yohkoh and RHESSI) and elaborate on their discoveries. These have both helped with white-light flares both directly and also with closely related X-ray and γ-ray emissions), with the result that this article leans heavily in that direction.

  10. Biological Collections: Chasing the Ideal

    PubMed Central

    Kamenski, P. A.; Sazonov, A. E.; Fedyanin, A. A.; Sadovnichy, V. A.

    2016-01-01

    This article is based on the results of an analysis of existing biological collections in Russia and abroad set up in the framework of the project “Scientific Basis of the National Biobank –Depository of Living Systems” by M.V. Lomonosov Moscow State University [1]. PMID:27437135

  11. Stateline: Chasing the Bullies Away

    ERIC Educational Resources Information Center

    Christie, Kathy

    2005-01-01

    In its 2003 report, School Survey on Crime and Safety, the National Center on Education Statistics (NCES) found that, during the 1999-2000 school year, 29% of schools reported having more difficulty with student bullying than with any other single discipline problem. A similar 2004 NCES report, Indicators of School Crime and Safety, found that, in…

  12. Running in Circles: Chasing Dewey

    ERIC Educational Resources Information Center

    Glassman, Michael

    2004-01-01

    This paper explores the impact of John Dewey on the field of educational psychology. Dewey raised issues and ideas, such as the role of context and the reapproximation of knowledge, that would come to haunt education and psychology for the next century. And yet soon after the turn of the twentieth century, Dewey abandoned psychology and redefined…

  13. Chasing Meteors With a Microscope.

    ERIC Educational Resources Information Center

    Jones, Richard C.

    1993-01-01

    Describes types of meteors and micrometeorites that enter the Earth's atmosphere. Presents an activity where students collect micrometeorites with a strip of tape in an undisturbed outdoor area. After 24 hours, they examine the tape by sandwiching it between 2 glass slides and view through a microscope at 100X. (PR)

  14. THE SPECTRAL ENERGY DISTRIBUTIONS AND INFRARED LUMINOSITIES OF z Almost-Equal-To 2 DUST-OBSCURED GALAXIES FROM Herschel AND Spitzer

    SciTech Connect

    Melbourne, J.; Soifer, B. T.; Desai, Vandana; Armus, Lee; Pope, Alexandra; Alberts, Stacey; Dey, Arjun; Jannuzi, B. T.; Bussmann, R. S. E-mail: bts@submm.caltech.edu E-mail: lee@ipac.caltech.edu E-mail: pope@astro.umass.edu E-mail: jannuzi@noao.edu

    2012-05-15

    Dust-obscured galaxies (DOGs) are a subset of high-redshift (z Almost-Equal-To 2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L{sub IR} > 10{sup 12} L{sub Sun} ). We present new far-infrared photometry, at 250, 350, and 500 {mu}m (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 10{sup 11.6} L{sub Sun} 10{sup 13} L{sub Sun }. The rest-frame near-IR (1-3 {mu}m) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths. DOGs with 'power-law' SEDs in the rest-frame near-IR show observed-frame 250/24 {mu}m flux density ratios similar to the QSO-like local ULIRG, Mrk 231. DOGs with a stellar 'bump' in their rest-frame near-IR show observed-frame 250/24 {mu}m flux density ratios similar to local star-bursting ULIRGs like NGC 6240. None show 250/24 {mu}m flux density ratios similar to extreme local ULIRG, Arp 220; though three show 350/24 {mu}m flux density ratios similar to Arp 220. For the Herschel-detected DOGs, accurate estimates (within {approx}25%) of total IR luminosity can be predicted from their rest-frame mid-IR data alone (e.g., from Spitzer observed-frame 24 {mu}m luminosities). Herschel-detected DOGs tend to have a high ratio of infrared luminosity to rest-frame 8 {mu}m luminosity (the IR8 = L{sub IR}(8-1000 {mu}m)/{nu}L{sub {nu}}(8 {mu}m) parameter of Elbaz et al.). Instead of lying on the z = 1-2 'infrared main sequence' of star-forming galaxies (like typical LIRGs and ULIRGs at those epochs) the DOGs, especially large fractions of

  15. The separation of two hymenopteran parasitoids, Tersilochus obscurator and Tersilochus microgaster (Ichneumonidae), of stem-mining pests of winter oilseed rape using DNA, morphometric and ecological data.

    PubMed

    Barari, H; Ferguson, A W; Piper, R W; Smith, E; Quicke, D L J; Williams, I H

    2005-08-01

    Tersilochus obscurator Aubert and Tersilochus microgaster (Szépligeti) are larval endoparasitoids of economically-important stem-mining pests of winter oilseed rape (Brassica napus L.) in Europe. They are difficult to separate morphologically. Their hosts are Ceutorhynchus pallidactylus (Marsham) and Psylliodes chrysocephala Linnaeus, respectively. The parasitoids' taxonomic status, identification, host range and phenology were studied using genetic, morphometric and ecological data. The study used 527 female parasitoids from the UK and Germany, either field-collected in emergence traps or reared from field-collected host larvae. Two morphometric characters, the ovipositor sheath to first metasomal tergite ratio and the percentage of the mesopleuron spanned by the sternaulus, were measured. A 440 bp section of mitochondrial DNA cytochrome oxidase subunit I (COI) gene was sequenced from 35 parasitoids reared from C. pallidactylus, 20 reared from P. chrysocephala and individuals from two outgroups, Tersilochus heterocerus Thomson and Phradis interstitialis Thomson. Distinct and invariable COI sequences corresponded exclusively to each parasitoid group, confirming that T. obscurator and T. microgaster are discrete species. Measurements of host-reared and COI-sequenced specimens indicated that the ranges of both morphometric characters overlapped between species. Using these ranges as criteria, all but 3.6% of UK specimens and 2% of German specimens were identifiable to species without reference to host or phenology. There were differences in emergence phenology in the UK, adult T. microgaster emerging from winter diapause by 29 March 2000, T. obscurator emerging between 12 April and 24 May 2000. The value of molecular techniques in the identification of closely-related parasitoid species is discussed.

  16. Chasing the Black Smoke: Building Software for CALIPSO Satellite Data to Aid in Tracking and Identifying Sources of Aerosols and their Impact on the Earth's Climate

    NASA Astrophysics Data System (ADS)

    Mercer, G. A.

    2015-12-01

    The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite is a NASA Earth observation that analyzes aerosol particles suspended in the Earth's atmosphere. Researchers use visualized CALIPSO data to track the global distribution, dispersion, and source of aerosols. There currently exists a tool for displaying CALIPSO data, but this tool does not support needed features for tracking aerosols such as selecting regions of data and sharing those selected regions, making tracking specific airborne objects difficult for researchers. Adding these necessary features to the current CALIPSO visualization tool is difficult, as the tool is written in Interactive Data Language (IDL), a proprietary and obscure language and writing additional features for the tool would require a specialized development team. This topic will focus on release of a new tool for visualization CALIPSO's atmospheric data, or the Visualization of CALIPSO (VOCAL) open source Python program. The talk will explain why VOCAL will serve as the successor to the current visualization tool for CALIPSO data, what new features VOCAL brings to the table for researchers, and how this new tool can further support the tracking and identification of aerosols in the Earth's atmosphere.

  17. On R-W1 as A Diagnostic to Discover Obscured Active Galactic Nuclei in Wide-area X-Ray Surveys

    NASA Astrophysics Data System (ADS)

    LaMassa, Stephanie M.; Civano, Francesca; Brusa, Marcella; Stern, Daniel; Glikman, Eilat; Gallagher, Sarah; Urry, C. Meg; Cales, Sabrina; Cappelluti, Nico; Cardamone, Carolin; Comastri, Andrea; Farrah, Duncan; Greene, Jenny E.; Komossa, S.; Merloni, Andrea; Mroczkowski, Tony; Natarajan, Priyamvada; Richards, Gordon; Salvato, Mara; Schawinski, Kevin; Treister, Ezequiel

    2016-02-01

    Capitalizing on the all-sky coverage of WISE and the 35% and 50% sky coverage from Sloan Digital Sky Survey and Pan-STARRS, respectively, we explore the efficacy of mR (optical) - {m}3.4μ {{m}} (mid-infrared), hereafter R-W1, as a color diagnostic to identify obscured supermassive black hole accretion in wide-area X-ray surveys. We use the ˜16.5 deg2 Stripe 82 X-ray survey data as a test bed to compare R-W1 with R - K, an oft-used obscured active galactic nucleus (AGN) selection criterion, and examine where different classes of objects lie in this parameter space. Most stars follow a well-defined path in R - K versus R-W1 space. We demonstrate that optically normal galaxies hosting X-ray AGNs at redshifts 0.5\\lt z\\lt 1 can be recovered with an R-W1\\gt 4 color cut, while they typically are not selected as AGNs based on their W1-W2 colors. Additionally, different observed X-ray luminosity bins favor different regions in R-W1 parameter space: moderate-luminosity AGNs (1043 erg {{{s}}}-1\\lt {L}0.5-10{keV}\\lt {10}44 erg s-1) tend to have red colors, while the highest-luminosity AGNs ({L}0.5-10{keV}\\gt {10}45 erg s-1) have bluer colors; higher spectroscopic completeness of the Stripe 82X sample is needed to determine whether this is a selection effect or an intrinsic property. Finally, we parameterize X-ray obscuration of Stripe 82X AGNs by calculating their hardness ratios (HRs) and find no clear trends between HR and optical reddening. Our results will help inform best-effort practices in following up obscured AGN candidates in current and future wide-area, shallow X-ray surveys, including the all-sky eROSITA mission.

  18. Exploring the molecular chemistry and excitation in obscured luminous infrared galaxies. An ALMA mm-wave spectral scan of NGC 4418

    NASA Astrophysics Data System (ADS)

    Costagliola, F.; Sakamoto, K.; Muller, S.; Martín, S.; Aalto, S.; Harada, N.; van der Werf, P.; Viti, S.; Garcia-Burillo, S.; Spaans, M.

    2015-10-01

    Context. Extragalactic observations allow the study of molecular chemistry and excitation under physical conditions which may differ greatly from those found in the Milky Way. The compact, obscured nuclei (CON) of luminous infrared galaxies (LIRG) combine large molecular columns with intense infrared (IR), ultra-violet (UV), and X- radiation and represent ideal laboratories for the study of the chemistry of the interstellar medium (ISM) under extreme conditions. Aims: Our aim was to obtain for the first time a multi-band spectral scan of a LIRG, and to derive molecular abundances and excitation to be compared to other Galactic and extragalactic environments. Methods: We obtained an ALMA Cycle 0 spectral scan of the dusty LIRG NGC 4418, spanning a total of 70.7 GHz in bands 3, 6, and 7. We use a combined local thermal equilibrium (LTE) and non-LTE (NLTE) fit of the spectrum in order to identify the molecular species and to derive column densities and excitation temperatures. We derive molecular abundances and compare them with other Galactic and extragalactic sources by means of a principal component analysis. Results: We detect 317 emission lines from a total of 45 molecular species, including 15 isotopic substitutions and 6 vibrationally excited variants. Our LTE/NLTE fit find kinetic temperatures from 20 to 350 K, and densities between 105 and 107 cm-3. The spectrum is dominated by vibrationally excited HC3N, HCN, and HNC, with vibrational temperatures from 300 to 450 K. We find that the chemistry of NCG 4418 is characterized by high abundances of HC3N, SiO, H2S, and c-HCCCH but a low CH3OH abundance. A principal component analysis shows that NGC 4418 and Arp 220 share very similar molecular abundances and excitation, which clearly set them apart from other Galactic and extragalactic environments. Conclusions: Our spectral scan confirms that the chemical complexity in the nucleus of NGC 4418 is one of the highest ever observed outside our Galaxy. The similar

  19. FINDING η CAR ANALOGS IN NEARBY GALAXIES USING Spitzer. II. IDENTIFICATION OF AN EMERGING CLASS OF EXTRAGALACTIC SELF-OBSCURED STARS

    SciTech Connect

    Khan, Rubab; Kochanek, C. S.; Stanek, K. Z.; Gerke, Jill

    2015-02-01

    Understanding the late-stage evolution of the most massive stars such as η Carinae is challenging because no true analogs of η Car have been clearly identified in the Milky Way or other galaxies. In Khan et al., we utilized Spitzer IRAC images of 7 nearby (≲ 4 Mpc) galaxies to search for such analogs, and found 34 candidates with flat or red mid-IR spectral energy distributions. Here, in Paper II, we present our characterization of these candidates using multi-wavelength data from the optical through the far-IR. Our search detected no true analogs of η Car, which implies an eruption rate that is a fraction 0.01 ≲ F ≲ 0.19 of the core-collapse supernova (ccSN) rate. This is roughly consistent with each M {sub ZAMS} ≳ 70 M {sub ☉} star undergoing one or two outbursts in its lifetime. However, we do identify a significant population of 18 lower luminosity (log (L/L {sub ☉}) ≅ 5.5-6.0) dusty stars. Stars enter this phase at a rate that is a fraction 0.09 ≲ F ≲ 0.55 of the ccSN rate, and this is consistent with all 25 < M {sub ZAMS} < 60 M {sub ☉} stars undergoing an obscured phase at most lasting a few thousand years once or twice. These phases constitute a negligible fraction of post-main-sequence lifetimes of massive stars, which implies that these events are likely to be associated with special periods in the evolution of the stars. The mass of the obscuring material is of order ∼M {sub ☉}, and we simply do not find enough heavily obscured stars for theses phases to represent more than a modest fraction (∼10% not ∼50%) of the total mass lost by these stars. In the long term, the sources that we identified will be prime candidates for detailed physical analysis with the James Webb Space Telescope.

  20. Synchrotron-based rotationally resolved high-resolution FTIR spectroscopy of azulene and the unidentified infrared bands of astronomy.

    PubMed

    Albert, Sieghard; Lerch, Philippe; Quack, Martin

    2013-10-01

    Chasing the unidentified IR bands: The first rotationally resolved high-resolution infrared spectrum of azulene is reported using synchrotron Fourier transform infrared spectroscopy including a rovibrational analysis of the out-of-plane fundamental ν44. Comparison of azulene, naphthalene, indole, and biphenyl infrared bands leads to coincidences with UIR bands at 12.8 μm with naphthalene and at 13.55 and 14.6 μm with biphenyl bands, but excluding azulene as a strong absorber.

  1. Black hole growth and starburst activity at z = 0.6-4 in the Chandra Deep Field South. Host galaxies properties of obscured AGN

    NASA Astrophysics Data System (ADS)

    Brusa, M.; Fiore, F.; Santini, P.; Grazian, A.; Comastri, A.; Zamorani, G.; Hasinger, G.; Merloni, A.; Civano, F.; Fontana, A.; Mainieri, V.

    2009-12-01

    Aims: The co-evolution of host galaxies and the active black holes which reside in their centre is one of the most important topics in modern observational cosmology. Here we present a study of the properties of obscured active galactic nuclei (AGN) detected in the CDFS 1 Ms observation and their host galaxies. Methods: We limited the analysis to the MUSIC area, for which deep K-band observations obtained with ISAAC@VLT are available, ensuring accurate identifications of the counterparts of the X-ray sources as well as reliable determination of photometric redshifts and galaxy parameters, such as stellar masses and star formation rates. In particular, we: 1) refined the X-ray/infrared/optical association of 179 sources in the MUSIC area detected in the Chandra observation; 2) studied the host galaxies observed and rest frame colors and properties. Results: We found that X-ray selected (LX ⪆ 1042 erg s-1) AGN show Spitzer colors consistent with both AGN and starburst dominated infrared continuum; the latter would not have been selected as AGN from infrared diagnostics. The host galaxies of X-ray selected obscured AGN are all massive (Mast > 1010 M_⊙) and, in 50% of the cases, are also actively forming stars (1/SSFR < tHubble) in dusty environments. The median L/LEdd value of the active nucleus is between 2% and 10% depending on the assumed MBH/Mast ratio. Finally, we found that the X-ray selected AGN fraction increases with the stellar mass up to a value of 30% at z > 1 and Mast > 3 × 1011 M_⊙, a fraction significantly higher than in the local Universe for AGN of similar luminosities. Tables [see full textsee full textsee full text] and [see full textsee full textsee full text] are only available in electronic form at http://www.aanda.org

  2. The composite nature of Dust-Obscured Galaxies (DOGs) at z ˜ 2-3 in the COSMOS field - I. A far-infrared view

    NASA Astrophysics Data System (ADS)

    Riguccini, L.; Le Floc'h, E.; Mullaney, J. R.; Menéndez-Delmestre, K.; Aussel, H.; Berta, S.; Calanog, J.; Capak, P.; Cooray, A.; Ilbert, O.; Kartaltepe, J.; Koekemoer, A.; Lutz, D.; Magnelli, B.; McCracken, H.; Oliver, S.; Roseboom, I.; Salvato, M.; Sanders, D.; Scoville, N.; Taniguchi, Y.; Treister, E.

    2015-09-01

    Dust-Obscured Galaxies (DOGs) are bright 24 μm-selected sources with extreme obscuration at optical wavelengths. They are typically characterized by a rising power-law continuum of hot dust (TD ˜ 200-1000 K) in the near-IR indicating that their mid-IR luminosity is dominated by an active galactic nucleus (AGN). DOGs with a fainter 24 μm flux display a stellar bump in the near-IR and their mid-IR luminosity appears to be mainly powered by dusty star formation. Alternatively, it may be that the mid-IR emission arising from AGN activity is dominant but the torus is sufficiently opaque to make the near-IR emission from the AGN negligible with respect to the emission from the host component. In an effort to characterize the astrophysical nature of the processes responsible for the IR emission in DOGs, this paper exploits Herschel data (PACS + SPIRE) on a sample of 95 DOGs within the COSMOS field. We derive a wealth of far-IR properties (e.g. total IR luminosities; mid-to-far-IR colours; dust temperatures and masses) based on spectral energy distribution fitting. Of particular interest are the 24 μm-bright DOGs (F24 μm > 1 mJy). They present bluer far-IR/mid-IR colours than the rest of the sample, unveiling the potential presence of an AGN. The AGN contribution to the total 8-1000 μm flux increases as a function of the rest-frame 8 μm-luminosity irrespective of the redshift. This confirms that faint DOGs (L8 μm < 1012 L⊙) are dominated by star formation while brighter DOGs show a larger contribution from an AGN.

  3. Evaluate and characterize mechanisms controlling transport, fate, and effects of army smokes in the aerosol wind tunnel: Transport, transformations, fate, and terrestrial ecological effects of hexachloroethane obscurant smokes

    SciTech Connect

    Cataldo, D.A.; Ligotke, M.W.; Bolton, H. Jr.; Fellows, R.J.; Van Voris, P.; McVeety, B.D.; Li, Shu-mei W.; McFadden, K.M.

    1989-09-01

    The terrestrial transport, chemical fate, and ecological effects of hexachloroethane (HC) smoke were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on exposure scenarios, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of HC smoke/obscurants is establishing the importance of environmental parameters such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and two soil types. HC aerosols were generated in a controlled atmosphere wind tunnel by combustion of hexachloroethane mixtures prepared to simulate normal pot burn rates and conditions. The aerosol was characterized and used to expose plant, soil, and other test systems. Particle sizes of airborne HC ranged from 1.3 to 2.1 {mu}m mass median aerodynamic diameter (MMAD), and particle size was affected by relative humidity over a range of 20% to 85%. Air concentrations employed ranged from 130 to 680 mg/m{sup 3}, depending on exposure scenario. Chlorocarbon concentrations within smokes, deposition rates for plant and soil surfaces, and persistence were determined. The fate of principal inorganic species (Zn, Al, and Cl) in a range of soils was assessed.

  4. Evaluate and characterize mechanisms controlling transport, fate and effects of army smokes in an aerosol wind tunnel: Transport, transformations, fate and terrestrial ecological effects of fog oil obscurant smokes: Final report

    SciTech Connect

    Cataldo, D.A.; Van Voris, P.; Ligotke, M.W.; Fellows, R.J.; McVeety, B.D.; Li, Shu-mei W.; Bolton, H. Jr.; Fredrickson, J.K.

    1989-01-01

    The terrestrial transport, chemical fate, and ecological effects of fog oil (FO) smoke obscurants were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on an exposure scenario, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of fog oil smoke/obscurants is establishing the importance of environmental parameters, such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and three soil types. 29 refs., 35 figs., 32 tabs.

  5. Infrared astronomy research and high altitude observations

    NASA Technical Reports Server (NTRS)

    Jones, B.; Stein, W. A.; Willner, S. P.; Soifer, B. T.

    1984-01-01

    Highlights are presented of studies of the emission mechanisms in the 4 to 8 micron region of the spectrum using a circular variable filter wheel spectrometer with a PbSnTe photovoltaic detector. Investigations covered include the spectroscopy of planets, stellar atmospheres, highly obscured objects in molecular clouds, planetary nebulae, H2 regions, and extragalactic objects.

  6. Tinea capitis caused by Trichophyton tonsurans presenting as an obscure patchy hair loss due to daily antifungal shampoo use.

    PubMed

    Sombatmaithai, Alita; Pattanaprichakul, Penvadee; Tuchinda, Papapit; Surawan, Theetat; Muanprasart, Chanai; Matthapan, Lalita; Bunyaratavej, Sumanas

    2015-04-01

    Tinea capitis is unusual and often misdiagnosed in healthy adults. We report a case of a healthy woman with a several-year history of asymptomatic, bizarre-shaped, non-scarring alopecia. She had used over-the-counter ketoconazole shampoo regularly for a long time. An initial potassium hydroxide preparation showed negative result for fungal organism. The scalp biopsy revealed endothrix infection, and dermoscopic examination demonstrated the comma hair and corkscrew hair signs. The fungal culture showed Trichophyton tonsurans. The daily use of antifungal shampoo could be the important factor to conceal clinical and laboratory findings for diagnosis of T. tonsurans tinea capitis in our case, which required high clinical suspicion and histopathology and dermoscopic examinations. PMID:26114071

  7. Tinea capitis caused by Trichophyton tonsurans presenting as an obscure patchy hair loss due to daily antifungal shampoo use

    PubMed Central

    Sombatmaithai, Alita; Pattanaprichakul, Penvadee; Tuchinda, Papapit; Surawan, Theetat; Muanprasart, Chanai; Matthapan, Lalita; Bunyaratavej, Sumanas

    2015-01-01

    Tinea capitis is unusual and often misdiagnosed in healthy adults. We report a case of a healthy woman with a several-year history of asymptomatic, bizarre-shaped, non-scarring alopecia. She had used over-the-counter ketoconazole shampoo regularly for a long time. An initial potassium hydroxide preparation showed negative result for fungal organism. The scalp biopsy revealed endothrix infection, and dermoscopic examination demonstrated the comma hair and corkscrew hair signs. The fungal culture showed Trichophyton tonsurans. The daily use of antifungal shampoo could be the important factor to conceal clinical and laboratory findings for diagnosis of T. tonsurans tinea capitis in our case, which required high clinical suspicion and histopathology and dermoscopic examinations. PMID:26114071

  8. Tinea capitis caused by Trichophyton tonsurans presenting as an obscure patchy hair loss due to daily antifungal shampoo use.

    PubMed

    Sombatmaithai, Alita; Pattanaprichakul, Penvadee; Tuchinda, Papapit; Surawan, Theetat; Muanprasart, Chanai; Matthapan, Lalita; Bunyaratavej, Sumanas

    2015-04-01

    Tinea capitis is unusual and often misdiagnosed in healthy adults. We report a case of a healthy woman with a several-year history of asymptomatic, bizarre-shaped, non-scarring alopecia. She had used over-the-counter ketoconazole shampoo regularly for a long time. An initial potassium hydroxide preparation showed negative result for fungal organism. The scalp biopsy revealed endothrix infection, and dermoscopic examination demonstrated the comma hair and corkscrew hair signs. The fungal culture showed Trichophyton tonsurans. The daily use of antifungal shampoo could be the important factor to conceal clinical and laboratory findings for diagnosis of T. tonsurans tinea capitis in our case, which required high clinical suspicion and histopathology and dermoscopic examinations.

  9. The obscure events contributing to the evolution of an incipient sex chromosome in Populus A retrospective working hypothesis.

    SciTech Connect

    Tuskan, Gerald A; Tschaplinski, Timothy J; Chen, Jay; Labbe, Jessy L; Ranjan, Priya; DiFazio, Steven P; Slavov, Goncho T.; Yin, Tongming

    2012-01-01

    Genetic determination of gender is a fundamental developmental and evolutionary process in plants. Although it appears that dioecy in Populus is partially genetically controlled, the precise gender-determining systems remain unclear. The recently-released second draft assembly and annotated gene set of the Populus genome provided an opportunity to re-visit this topic. We hypothesized that over evolutionary time, selective pressure has reformed the genome structure and gene composition in the peritelomeric region of the chromosome XIX which has resulted in a distinctive genome structure and cluster of genes contributing to gender determination in Populus. Multiple lines of evidence support this working hypothesis. First, the peritelomeric region of the chromosome XIX contains significantly fewer single nucleotide polymorphisms than the rest of Populus genome and has a distinct evolutionary history. Second, the peritelomeric end of chromosome XIX contains the largest cluster of the nucleotide-binding site-leucine-rich repeat (NBS-LRR) class of disease resistances genes in the entire Populus genome. Third, there is a high occurrence of small microRNAs on chromosome XIX coincident to the region containing the putative gender-determining locus and the major cluster of NBS-LRR genes. Further, by analyzing the metabolomic profiles of floral bud in male and female Populus trees using a gas chromatography-mass spectrometry, we found there are gender-specific accumulations of phenolic glycosides. Taken together, these findings provide new insights into the genetic control of gender determination in Populus.

  10. Spindle cell rhabdomyosarcoma of the retroperitoneum: an unusual case developed in a pregnant woman but obscured by pregnancy

    PubMed Central

    Yu, Lu; Yang, Shou Jing

    2014-01-01

    Spindle cell rhabdomyosarcoma (RMS) is an uncommon histiologic variant of RMS that has spindle cell morphology. This tumor occurs almost exclusively in childhood and more rarely in adults. Only a few adult cases, including two retroperitoneal cases in male patients, have been documented previously. We describe a rare case of spindle cell RMS of the retroperitoneum in a 37-year-old woman developed during pregnancy and incidentally discovered after vaginal delivery. Computed tomography showed a huge tumor mass, measured 20 × 20 × 15 cm in size, arising in retroperitoneal space. Histologically, the tumor consisted of spindle cells arranged in a fascicular or herringbone growth pattern, morphologically mimicking adult fibrosarcoma, intermingled with scattered rhabdomyoblasts. Mitotic activity ranged from 20 to 28 mitoses per 10 high-power fields and tumor necrosis was evident. Immunohistochemically, tumor cells were stained diffusely positive for muscle specific actin, desmin, and vimentin, scattered positive for myogenin, MyoD1 and myoglobin, with a Ki-67 (MIB-1) proliferative labeling index of 46.11%. This tumor also stains positively for CD99, strong cytoplasmic WT1, and nuclear p53. Other markers such as S100 protein, smooth muscle specific actin, CD34, cytokeratin, and epithelial membrane antigen were all negative in the tumor cells. On the basis of the findings, a spindle cell RMS was diagnosed. The neoplasm was incompletely excised because of encasement of major vessels and invasion to adjacent structures, and additional chemotherapy was given. PMID:25197361

  11. Recurrent hybridization and recent origin obscure phylogenetic relationships within the 'white-headed' gull (Larus sp.) complex.

    PubMed

    Sonsthagen, Sarah A; Wilson, Robert E; Chesser, R Terry; Pons, Jean-Marc; Crochet, Pierre-Andre; Driskell, Amy; Dove, Carla

    2016-10-01

    Species complexes that have undergone recent radiations are often characterized by extensive allele sharing due to recent ancestry and (or) introgressive hybridization. This can result in discordant evolutionary histories of genes and heterogeneous genomes, making delineating species limits difficult. Here we examine the phylogenetic relationships among a complex group of birds, the white-headed gulls (Aves: Laridae), which offer a unique window into the speciation process due to their recent evolutionary history and propensity to hybridize. Relationships were examined among 17 species (61 populations) using a multilocus approach, including mitochondrial and nuclear intron DNA sequences and microsatellite genotype information. Analyses of microsatellite and intron data resulted in some species-based groupings, although most species were not represented by a single cluster. Considerable allele and haplotype sharing among white-headed gull species was observed; no locus contained a species-specific clade. Despite this, our multilocus approach provided better resolution among some species than previous studies. Interestingly, most clades appear to correspond to geographic locality: our BEAST analysis recovered strong support for a northern European/Icelandic clade, a southern European/Russian clade, and a western North American/canus clade, with weak evidence for a high latitude clade spanning North America and northwestern Europe. This geographical structuring is concordant with behavioral observations of pervasive hybridization in areas of secondary contact. The extent of allele and haplotype sharing indicates that ecological and sexual selection are likely not strong enough to complete reproductive isolation within several species in the white-headed gull complex. This suggests that just a few genes are driving the speciation process. PMID:27369453

  12. Social Responsibility in Tobacco Production? Tobacco Companies Use of Green Supply Chains to Obscure the Real Costs of Tobacco Farming

    PubMed Central

    Otañez, Marty

    2011-01-01

    Background Tobacco companies have come under increased criticism because of environmental and labor practices related to growing tobacco in developing countries. Methods Analysis of tobacco industry documents, industry web sites and interviews with tobacco farmers in Tanzania and tobacco farm workers, farm authorities, trade unionists, government officials and corporate executives from global tobacco leaf companies in Malawi. Results British American Tobacco and Philip Morris created supply chains in the 1990s to improve production efficiency, control, access to markets, and profits. In the 2000s, the companies used their supply chains in an attempt to legitimize their portrayals of tobacco farming as socially and environmentally friendly, rather than take meaningful steps to eliminate child labor and reduce deforestation in developing countries. The tobacco companies used nominal self-evaluation (not truly independent evaluators) and public relations to create the impression of social responsibility. The companies benefit from $1.2 billion in unpaid labor costs due to child labor and more than $64 million annually in costs that would have been made to avoid tobacco related deforestation in the top twelve tobacco growing developing countries, far exceeding the money they spend nominally working to change these practices. Conclusions The tobacco industry uses green supply chains to make tobacco farming in developing countries appear sustainable while continuing to purchase leaf produced with child labor and high rates of deforestation. Strategies to counter green supply chain schemes include securing implementing protocols for the WHO Framework Convention on Tobacco Control to regulate the companies’ practices at the farm level. PMID:21504915

  13. Recurrent hybridization and recent origin obscure phylogenetic relationships within the 'white-headed' gull (Larus sp.) complex.

    PubMed

    Sonsthagen, Sarah A; Wilson, Robert E; Chesser, R Terry; Pons, Jean-Marc; Crochet, Pierre-Andre; Driskell, Amy; Dove, Carla

    2016-10-01

    Species complexes that have undergone recent radiations are often characterized by extensive allele sharing due to recent ancestry and (or) introgressive hybridization. This can result in discordant evolutionary histories of genes and heterogeneous genomes, making delineating species limits difficult. Here we examine the phylogenetic relationships among a complex group of birds, the white-headed gulls (Aves: Laridae), which offer a unique window into the speciation process due to their recent evolutionary history and propensity to hybridize. Relationships were examined among 17 species (61 populations) using a multilocus approach, including mitochondrial and nuclear intron DNA sequences and microsatellite genotype information. Analyses of microsatellite and intron data resulted in some species-based groupings, although most species were not represented by a single cluster. Considerable allele and haplotype sharing among white-headed gull species was observed; no locus contained a species-specific clade. Despite this, our multilocus approach provided better resolution among some species than previous studies. Interestingly, most clades appear to correspond to geographic locality: our BEAST analysis recovered strong support for a northern European/Icelandic clade, a southern European/Russian clade, and