WorldWideScience

Sample records for red supergiants powered

  1. Astrophysics of Red Supergiants

    Science.gov (United States)

    Levesque, Emily M.

    2017-12-01

    'Astrophysics of Red Supergiants' is the first book of its kind devoted to our current knowledge of red supergiant stars, a key evolutionary phase that is critical to our larger understanding of massive stars. It provides a comprehensive overview of the fundamental physical properties of red supergiants, their evolution, and their extragalactic and cosmological applications. It serves as a reference for researchers from a broad range of fields (including stellar astrophysics, supernovae, and high-redshift galaxies) who are interested in red supergiants as extreme stages of stellar evolution, dust producers, supernova progenitors, extragalactic metallicity indicators, members of massive binaries and mergers, or simply as compelling objects in their own right. The book is accessible to a range of experience levels, from graduate students up to senior researchers.

  2. Infrared Model Spectra for Evolving Red Supergiants

    Directory of Open Access Journals (Sweden)

    Kyung-Won Suh

    1993-06-01

    Full Text Available The space and ground based infrared spectra of red supergiants are modeled and arranged in order of their evolutionary status with their theoretical model parameters. The chemical compositions of the dust shells around red supergiants are affected by the nuclear reaction and dredge-up processes of the cental stars. The processes are sensitively dependent on the initial mass, the initial chemical composition, and the evolutionary status. Miras, infrared carbon stars, and OH/IR stars have close link in their evolution in manu aspects, i,e., the chemical composition, the optical depths and the mass loss rates. The evolutionary tracks for the three classes of red supergiants on infrared two-color diagrams have been made from model calculations and IRAS observational data.

  3. The evolution of red supergiants to supernovae

    Science.gov (United States)

    Beasor, Emma R.; Davies, Ben

    2017-11-01

    With red supergiants (RSGs) predicted to end their lives as Type IIP core collapse supernova (CCSN), their behaviour before explosion needs to be fully understood. Mass loss rates govern RSG evolution towards SN and have strong implications on the appearance of the resulting explosion. To study how the mass-loss rates change with the evolution of the star, we have measured the amount of circumstellar material around 19 RSGs in a coeval cluster. Our study has shown that mass loss rates ramp up throughout the lifetime of an RSG, with more evolved stars having mass loss rates a factor of 40 higher than early stage RSGs. Interestingly, we have also found evidence for an increase in circumstellar extinction throughout the RSG lifetime, meaning the most evolved stars are most severely affected. We find that, were the most evolved RSGs in NGC2100 to go SN, this extra extinction would cause the progenitor's initial mass to be underestimated by up to 9M⊙.

  4. The red supergiant population in the Perseus arm

    Science.gov (United States)

    Dorda, R.; Negueruela, I.; González-Fernández, C.

    2018-04-01

    We present a new catalogue of cool supergiants in a section of the Perseus arm, most of which had not been previously identified. To generate it, we have used a set of well-defined photometric criteria to select a large number of candidates (637) that were later observed at intermediate resolution in the infrared calcium triplet spectral range, using a long-slit spectrograph. To separate red supergiants from luminous red giants, we used a statistical method, developed in previous works and improved in the present paper. We present a method to assign probabilities of being a red supergiant to a given spectrum and use the properties of a population to generate clean samples, without contamination from lower luminosity stars. We compare our identification with a classification done using classical criteria and discuss their respective efficiencies and contaminations as identification methods. We confirm that our method is as efficient at finding supergiants as the best classical methods, but with a far lower contamination by red giants than any other method. The result is a catalogue with 197 cool supergiants, 191 of which did not appear in previous lists of red supergiants. This is the largest coherent catalogue of cool supergiants in the Galaxy.

  5. Imaging Red Supergiants with VLT/SPHERE/ZIMPOL

    Science.gov (United States)

    Cannon, Emily

    2018-04-01

    In the red supergiant (RSG) phase of evolution massive stars show powerful stellar winds, which strongly influence the supernova (progenitor) properties and control the nature of the compact object that is left behind. Material that is lost in the stellar wind, together with that ejected in the final core collapse, contributes to the chemical enrichment of the local interstellar medium. The mass-loss properties of RSGs are however poorly constrained. Moreover, little is known about the wind driving mechanism. To provide better constraints on both mass-loss rates and physics, high angular resolution observations are needed to unveil the inner regions of the circumstellar environment, where the mass loss is triggered. Using the VLT-SPHERE/ZIMPOL adaptive optics imaging polarimeter, spatially resolved images of four nearby RSGs were obtained in four filters. From these data, we obtain information on geometrical structures in the inner wind, the onset radius and spatial distribution of dust grains, and dust properties such as grain size. As dust grains may play a role in initiating and/or driving the outflow, this could provide us with clues as to the wind driving mechanism.

  6. Astrometry of red supergiant VY Canis Majoris with VERA

    Science.gov (United States)

    Choi, Y. K.; Hirota, T.; Honma, M.; Kobayashi, H.

    2008-07-01

    We present observational results on the red supergiant VY Canis Majoris with VERA. We have observed 22 GHz H2O masers and 43 GHz SiO masers (v=1 and 2 J=1-0) around VY CMa for 13 months. We succesfully detected a parallax of 0.87 ± 0.08 mas, corresponding to the distance of 1.15 +0.10-0.09 kpc using H2O masers. As the result of phase-referencing analyses, we have measured absolute positions for both H2O masers and SiO masers. The H2O maser features show rapid expansion off the central star.

  7. Interacting supernovae from photoionization-confined shells around red supergiant stars

    Science.gov (United States)

    Mackey, Jonathan; Mohamed, Shazrene; Gvaramadze, Vasilii V.; Kotak, Rubina; Langer, Norbert; Meyer, Dominique M.-A.; Moriya, Takashi J.; Neilson, Hilding R.

    2014-08-01

    Betelgeuse, a nearby red supergiant, is a fast-moving star with a powerful stellar wind that drives a bow shock into its surroundings. This picture has been challenged by the discovery of a dense and almost static shell that is three times closer to the star than the bow shock and has been decelerated by some external force. The two physically distinct structures cannot both be formed by the hydrodynamic interaction of the wind with the interstellar medium. Here we report that a model in which Betelgeuse's wind is photoionized by radiation from external sources can explain the static shell without requiring a new understanding of the bow shock. Pressure from the photoionized wind generates a standing shock in the neutral part of the wind and forms an almost static, photoionization-confined shell. Other red supergiants should have much more massive shells than Betelgeuse, because the photoionization-confined shell traps up to 35 per cent of all mass lost during the red supergiant phase, confining this gas close to the star until it explodes. After the supernova explosion, massive shells dramatically affect the supernova light curve, providing a natural explanation for the many supernovae that have signatures of circumstellar interaction.

  8. IRC -10414: a bow-shock-producing red supergiant star

    Science.gov (United States)

    Gvaramadze, V. V.; Menten, K. M.; Kniazev, A. Y.; Langer, N.; Mackey, J.; Kraus, A.; Meyer, D. M.-A.; Kamiński, T.

    2014-01-01

    Most runaway OB stars, like the majority of massive stars residing in their parent clusters, go through the red supergiant (RSG) phase during their lifetimes. Nonetheless, although many dozens of massive runaways were found to be associated with bow shocks, only two RSG bow-shock-producing stars, Betelgeuse and μ Cep, are known to date. In this paper, we report the discovery of an arc-like nebula around the late M-type star IRC -10414 using the SuperCOSMOS H-alpha Survey. Our spectroscopic follow-up of IRC -10414 with the Southern African Large Telescope (SALT) showed that it is a M7 supergiant, which supports previous claims on the RSG nature of this star based on observations of its maser emission. This was reinforced by our new radio- and (sub)millimetre-wavelength molecular line observations made with the Atacama Pathfinder Experiment 12-m telescope and the Effelsberg 100-m radio telescope, respectively. The SALT spectrum of the nebula indicates that its emission is the result of shock excitation. This finding along with the arc-like shape of the nebula and an estimate of the space velocity of IRC -10414 (≈70 ± 20 km s-1) imply the bow shock interpretation for the nebula. Thus, IRC -10414 represents the third case of a bow-shock-producing RSG and the first one with a bow shock visible at optical wavelengths. We discuss the smooth appearance of the bow shocks around IRC -10414 and Betelgeuse and propose that one of the necessary conditions for stability of bow shocks generated by RSGs is the ionization of the stellar wind. Possible ionization sources of the wind of IRC -10414 are proposed and discussed.

  9. A period-luminosity relation for supergiant red variables in the Large Magellanic Cloud

    International Nuclear Information System (INIS)

    Feast, M.W.; Catchpole, R.M.; Carter, B.S.; Roberts, G.

    1980-01-01

    Infrared photometry for 24 red supergiant variables in the LMC is used to derive bolometric magnitudes. The existence of a period-luminosity relation for these stars is demonstrated and compared with theory. (author)

  10. Tests of two convection theories for red giant and red supergiant envelopes

    Science.gov (United States)

    Stothers, Richard B.; Chin, Chao-Wen

    1995-01-01

    Two theories of stellar envelope convection are considered here in the context of red giants and red supergiants of intermediate to high mass: Boehm-Vitense's standard mixing-length theory (MLT) and Canuto & Mazzitelli's new theory incorporating the full spectrum of turbulence (FST). Both theories assume incompressible convection. Two formulations of the convective mixing length are also evaluated: l proportional to the local pressure scale height (H(sub P)) and l proportional to the distance from the upper boundary of the convection zone (z). Applications to test both theories are made by calculating stellar evolutionary sequences into the red zone (z). Applications to test both theories are made by calculating stellar evolutionary sequences into the red phase of core helium burning. Since the theoretically predicted effective temperatures for cool stars are known to be sensitive to the assigned value of the mixing length, this quantity has been individually calibrated for each evolutionary sequence. The calibration is done in a composite Hertzsprung-Russell diagram for the red giant and red supergiant members of well-observed Galactic open clusters. The MLT model requires the constant of proportionality for the convective mixing length to vary by a small but statistically significant amount with stellar mass, whereas the FST model succeeds in all cases with the mixing lenghth simply set equal to z. The structure of the deep stellar interior, however, remains very nearly unaffected by the choices of convection theory and mixing lenghth. Inside the convective envelope itself, a density inversion always occurs, but is somewhat smaller for the convectively more efficient MLT model. On physical grounds the FST model is preferable, and seems to alleviate the problem of finding the proper mixing length.

  11. RED SUPERGIANTS AS COSMIC ABUNDANCE PROBES: THE SCULPTOR GALAXY NGC 300

    International Nuclear Information System (INIS)

    Gazak, J. Zachary; Kudritzki, Rolf; Bresolin, Fabio; Evans, Chris; Patrick, Lee; Davies, Ben; Bergemann, Maria; Plez, Bertrand; Bender, Ralf; Wegner, Michael; Bonanos, Alceste Z.; Williams, Stephen J.

    2015-01-01

    We present a quantitative spectroscopic study of 27 red supergiants (RSGs) in the Sculptor Galaxy NGC 300. J-band spectra were obtained using KMOS on the Very Large Telescope and studied with state of the art synthetic spectra including NLTE corrections for the strongest diagnostic lines. We report a central metallicity of [Z] = −0.03 ± 0.05 with a gradient of −0.083 ± 0.014 [dex/kpc], in agreement with previous studies of blue supergiants and H ii-region auroral line measurements. This result marks the first application of the J-band spectroscopic method to a population of individual RSG stars beyond the Local Group of galaxies and reveals the great potential of this technique

  12. Strong magnetic field generated by the extreme oxygen-rich red supergiant VY Canis Majoris

    Science.gov (United States)

    Shinnaga, Hiroko; Claussen, Mark J.; Yamamoto, Satoshi; Shimojo, Masumi

    2017-12-01

    Evolved stars experience high mass-loss rates forming thick circumstellar envelopes (CSEs). The circumstellar material is made of the result of stellar nucleosynthesis and, as such, plays a crucial role in the chemical evolution of galaxies and the universe. Since asymmetric geometries of CSEs are common, and with very complex structures for some cases, radiative pressure from the stars can explain only a small portion of the mass-loss processes; thus the essential driving mechanism is still unknown, particularly for high-mass stars. Here we report on magnetic field measurements associated with the well-known extreme red supergiant (RSG) VY Canis Majoris (VY CMa). We measured the linear polarization and the Zeeman splitting of the SiO v = 0, J = 1-0 transition using a sensitive radio interferometer. The measured magnetic field strengths are surprisingly high; their upper limits range between 150 and 650 G within 530 au (˜80 R*) of the star. The lower limit of the field strength is expected to be at least ˜10 G based on the high degree of linear polarization. Since the field strengths are very high, the magnetic field must be a key element in understanding the stellar evolution of VY CMa, as well as the dynamical and chemical evolution of the complex CSE of the star. M-type RSGs, with large stellar surface, were thought to be very slow rotators. This would seem to make a dynamo in operation difficult, and would also dilute any fossil magnetic field. At least for VY CMa, we expect that powerful dynamo processes must still be active to generate the intense magnetic field.

  13. Pulsating red giants and supergiants as probes of galaxy formation and evolution

    Science.gov (United States)

    Theodorus van Loon, Jacco; Javadi, Atefeh; Khosroshahi, Habib; Rezaei, Sara; Golshan, Roya; Saberi, Maryam

    2015-08-01

    We have developed new techniques to use pulsating red giant and supergiants stars to reconstruct the star formation history of galaxies over cosmological time, as well as using them to map the dust production across their host galaxies. We describe the large programme on the Local Group spiral galaxy Triangulum (M33), which we have monitored at near-infrared wavelengths for several years using the United Kingdom InfraRed Telescope in Hawai'i. We outline the methodology and present the results for the central square kiloparsec (Javadi et al. 2011a,b, 2013) and - fresh from the press - the disc of M33 (Javadi et al. 2015, and in preparation). We also describe the results from our application of this new technique to other nearby galaxies: the Magellanic Clouds (published in Rezaei et al. 2014), the dwarf galaxies NGC 147 and 185 (Golshan et al. in preparation), and Centaurus A.

  14. THE DISCOVERY OF A MASSIVE CLUSTER OF RED SUPERGIANTS WITH GLIMPSE

    International Nuclear Information System (INIS)

    Alexander, Michael J.; Kobulnicky, Henry A.; Clemens, Dan P.; Jameson, Katherine; Pinnick, April; Pavel, Michael

    2009-01-01

    We report the discovery of a previously unknown massive Galactic star cluster at l = 29. 0 22, b = -0. 0 20. Identified visually in mid-IR images from the Spitzer GLIMPSE survey, the cluster contains at least eight late-type supergiants, based on follow-up near-IR spectroscopy, and an additional 3-6 candidate supergiant members having IR photometry consistent with a similar distance and reddening. The cluster lies at a local minimum in the 13 CO column density and 8 μm emission. We interpret this feature as a hole carved by the energetic winds of the evolving massive stars. The 13 CO hole seen in molecular maps at V LSR ∼ 95 km s -1 corresponds to near/far kinematic distances of 6.1/8.7 ± 1 kpc. We calculate a mean spectrophotometric distance of 7.0 +3.7 -2.4 kpc, broadly consistent with the kinematic distances inferred. This location places it near the northern end of the Galactic bar. For the mean extinction of A V = 12.6 ± 0.5 mag (A K = 1.5 ± 0.1 mag), the color-magnitude diagram of probable cluster members is well fit by isochrones in the age range 18-24 Myr. The estimated cluster mass is ∼20,000 M sun . With the most massive original cluster stars likely deceased, no strong radio emission is detected in this vicinity. As such, this red supergiant (RSG) cluster is representative of adolescent massive Galactic clusters that lie hidden behind many magnitudes of dust obscuration. This cluster joins two similar RSG clusters as residents of the volatile region where the end of our Galaxy's bar joins the base of the Scutum-Crux spiral arm, suggesting a recent episode of widespread massive star formation there.

  15. ALMA observations of anisotropic dust mass loss in the inner circumstellar environment of the red supergiant VY Canis Majoris

    NARCIS (Netherlands)

    O'Gorman, E.; Vlemmings, W.; Richards, A.M.S.; Baudry, A.; De Beck, E.; Decin, L.; Harper, G.M.; Humphreys, E.M.; Kervella, P.; Khouri, T.; Muller, S.

    2015-01-01

    The processes leading to dust formation and the subsequent role it plays in driving mass loss in cool evolved stars is an area of intense study. Here we present high resolution ALMA Science Verification data of the continuum emission around the highly evolved oxygen-rich red supergiant VY CMa. These

  16. Submillimeter vibrationally excited water emission from the peculiar red supergiant VY Canis Majoris

    Science.gov (United States)

    Menten, K. M.; Philipp, S. D.; Güsten, R.; Alcolea, J.; Polehampton, E. T.; Brünken, S.

    2006-08-01

    Context: .Vibrationally excited emission from the SiO and H2O molecules probes the innermost circumstellar envelopes of oxygen-rich red giant and supergiant stars. VY CMa is the most prolific known emission source in these molecules. Aims: .Observations were made to search for rotational lines in the lowest vibrationally excited state of H2O. Methods: .The APEX telescope was used for observations of H2O lines at frequencies around 300 GHz. Results: .Two vibrationally excited H2O lines were detected, a third one could not be found. In one of the lines we find evidence for weak maser action, similar to known (sub)millimeter ν2 = 1 lines. We find that the other line's intensity is consistent with thermal excitation by the circumstellar infrared radiation field. Several SiO lines were detected together with the H2O lines.

  17. Unveiling the molecular bipolar outflow of the peculiar red supergiant VY Canis Majoris

    Science.gov (United States)

    Shinnaga, Hiroko; Claussen, Mark J.; Lim, Jeremy; Dinh-van-Trung; Tsuboi, Masato

    2003-04-01

    We carried out polarimetric spectral-line imaging of the molecular outflow of the peculiar red supergiant VY Canis Majoris in SiO J=1-0 line in the ground vibrational state, which contains highly linearly-polarized velocity components, using the Very Large Array. We succeeded in unveiling the highly linearly polarized bipolar outflow for the first time at subarcsecond spatial resolution. The results clearly show that the direction of linear polarization of the brightest maser components is parallel to the outflow axis. The results strongly suggest that the linear polarization of the SiO maser is closely related to the outflow phenomena of the star. Furthermore, the results indicate that the linear polarization observed in the optical and infrared also occur due to the outflow phenomena.

  18. Astrometry of the Red Supergiant Star VY Canis Majoris with VERA

    Science.gov (United States)

    Choi, Y. K.; Hirota, T.; Honma, M.; Kobayashi, H.

    2009-08-01

    We present observational results on the red supergiant VY Canis Majoris with VERA. We have observed 22 GHz H_2O masers and 43 GHz SiO masers (v=1 and 2 J=1-0) around VY CMa for 13 months. We successfully detected a parallax of 0.87 ± 0.08 mas, corresponding to 1.15 +0.10 -0.09 kpc of distance using H_2O masers. As results of phase--referencing analyses, we have measured absolute positions for both the H_2O masers and SiO masers. The proper motions of the H_2O masers show the tendency of expansion.

  19. RED SUPERGIANT STARS AS COSMIC ABUNDANCE PROBES: KMOS OBSERVATIONS IN NGC 6822

    International Nuclear Information System (INIS)

    Patrick, L. R.; Evans, C. J.; Ferguson, A. M. N.; Davies, B.; Kudritzki, R-P.; Gazak, J. Z.; Bergemann, M.; Plez, B.

    2015-01-01

    We present near-IR spectroscopy of red supergiant (RSG) stars in NGC 6822, obtained with the new K-band Multi-Object Spectrograph Very Large Telescope, Chile. From comparisons with model spectra in the J-band we determine the metallicity of 11 RSGs, finding a mean value of [Z] = −0.52 ± 0.21, which agrees well with previous abundance studies of young stars and H ii regions. We also find an indication for a low-significance abundance gradient within the central 1 kpc. We compare our results with those derived from older stellar populations and investigate the difference using a simple chemical evolution model. By comparing the physical properties determined for RSGs in NGC 6822 with those derived using the same technique in the Galaxy and the Magellanic Clouds, we show that there appears to be no significant temperature variation of RSGs with respect to metallicity, in contrast to recent evolutionary models

  20. The initial masses of the red supergiant progenitors to Type II supernovae

    Science.gov (United States)

    Davies, Ben; Beasor, Emma R.

    2018-02-01

    There are a growing number of nearby supernovae (SNe) for which the progenitor star is detected in archival pre-explosion imaging. From these images it is possible to measure the progenitor's brightness a few years before explosion, and ultimately estimate its initial mass. Previous work has shown that II-P and II-L SNe have red supergiant (RSG) progenitors, and that the range of initial masses for these progenitors seems to be limited to ≲ 17 M⊙. This is in contrast with the cut-off of 25-30 M⊙ predicted by evolutionary models, a result that is termed the `red supergiant problem'. Here we investigate one particular source of systematic error present in converting pre-explosion photometry into an initial mass, which of the bolometric correction (BC) used to convert a single-band flux into a bolometric luminosity. We show, using star clusters, that RSGs evolve to later spectral types as they approach SN, which in turn causes the BC to become larger. Failure to account for this results in a systematic underestimate of a star's luminosity, and hence its initial mass. Using our empirically motivated BCs we reappraise the II-P and II-L SNe that have their progenitors detected in pre-explosion imaging. Fitting an initial mass function to these updated masses results in an increased upper mass cut-off of Mhi = 19.0^{+2.5}_{-1.3} M⊙, with a 95 per cent upper confidence limit of <27 M⊙. Accounting for finite sample size effects and systematic uncertainties in the mass-luminosity relationship raises the cut-off to Mhi = 25 M⊙ (<33 M⊙, 95 per cent confidence). We therefore conclude that there is currently no strong evidence for `missing' high-mass progenitors to core-collapse SNe.

  1. Type IIP supernova light curves affected by the acceleration of red supergiant winds

    Science.gov (United States)

    Moriya, Takashi J.; Förster, Francisco; Yoon, Sung-Chul; Gräfener, Götz; Blinnikov, Sergei I.

    2018-05-01

    We introduce the first synthetic light-curve model set of Type IIP supernovae exploded within circumstellar media in which the acceleration of the red supergiant winds is taken into account. Because wind acceleration makes the wind velocities near the progenitors low, the density of the immediate vicinity of the red supergiant supernova progenitors can be higher than that extrapolated by using a constant terminal wind velocity. Therefore, even if the mass-loss rate of the progenitor is relatively low, it can have a dense circumstellar medium at the immediate stellar vicinity and the early light curves of Type IIP supernovae are significantly affected by it. We adopt a simple β velocity law to formulate the wind acceleration. We provide bolometric and multicolour light curves of Type IIP supernovae exploding within such accelerated winds from the combinations of three progenitors, 12-16 M⊙; five β, 1-5; seven mass-loss rates, 10-5-10-2 M⊙ yr-1; and four explosion energies, (0.5-2) × 1051 erg. All the light-curve models are available at https://goo.gl/o5phYb. When the circumstellar density is sufficiently high, our models do not show a classical shock breakout as a consequence of the interaction with the dense and optically thick circumstellar media. Instead, they show a delayed `wind breakout', substantially affecting early light curves of Type IIP supernovae. We find that the mass-loss rates of the progenitors need to be 10-3-10-2 M⊙ yr-1 to explain typical rise times of 5-10 d in Type IIP supernovae assuming a dense circumstellar radius of 1015 cm.

  2. Quantitative spectroscopic J-band study of red supergiants in Perseus OB-1

    International Nuclear Information System (INIS)

    Gazak, J. Zachary; Kudritzki, Rolf; Davies, Ben; Bergemann, Maria; Plez, Bertrand

    2014-01-01

    We demonstrate how the metallicities of red supergiant (RSG) stars can be measured from quantitative spectroscopy down to resolutions of ≈3000 in the J-band. We have obtained high resolution spectra on a sample of the RSG population of h and χ Persei, a double cluster in the solar neighborhood. We show that careful application of the MARCS model atmospheres returns measurements of Z consistent with solar metallicity. Using two grids of synthetic spectra–one in pure LTE and one with non-LTE (NLTE) calculations for the most important diagnostic lines–we measure Z = +0.04 ± 0.10 (LTE) and Z = –0.04 ± 0.08 (NLTE) for the sample of eleven RSGs in the cluster. We degrade the spectral resolution of our observations and find that those values remain consistent down to resolutions of less than λ/δλ of 3000. Using measurements of effective temperatures we compare our results with stellar evolution theory and find good agreement. We construct a synthetic cluster spectrum and find that analyzing this composite spectrum with single-star RSG models returns an accurate metallicity. We conclude that the RSGs make ideal targets in the near infrared for measuring the metallicities of star forming galaxies out to 7-10 Mpc and up to 10 times farther by observing the integrated light of unresolved super star clusters.

  3. An Interferometric 270--355 GHz Spectral Line Survey of the Red Supergiant VY CMa

    Science.gov (United States)

    Menten, K. M.; Young, K. H.; Patel, N. A.; Gottlieb, C. A.; Thaddeus, P.; McCarthy, M. C.; Gurwell, M. A.; Belloche, A.; Kaminski, T.; Verheyen, L.; Decin, L.; Brunken, S.; Holger, S. P. M.

    2011-05-01

    We have used the Submillimeter Array to image the molecular line emission in the circumstellar envelope of the peculiar red supergiant star VY Canis Majoris over the whole 870 μm atmospheric window. Employing adaptive calibration using the object's continuum emission we achieve high quality one arcsecond resolution imaging of the whole 280--355 GHz range within which we find 211 distinct spectral lines from 33 molecules (including isotopologues) plus 40 unidentified lines. From the distribution of molecules we are obtaining their abundances and isotopologic abundance ratios. Using data for multiple transitions in a number of molecules we are deriving the physical conditions in the circumstellar envelope to reach a picture of the star's chemistry that can be compared with models. Our legacy survey is accompanied by a strong laboratory effort that helps with the identification of possibly newly found molecules traced by unidentified lines. We shall create a publicly accessible database of spectral-line channel-maps of the emission from all the lines detected in the survey.

  4. On the stability of bow shocks generated by red supergiants: the case of IRC -10414

    Science.gov (United States)

    Meyer, D. M.-A.; Gvaramadze, V. V.; Langer, N.; Mackey, J.; Boumis, P.; Mohamed, S.

    2014-03-01

    In this Letter, we explore the hypothesis that the smooth appearance of bow shocks around some red supergiants (RSGs) might be caused by the ionization of their winds by external sources of radiation. Our numerical simulations of the bow shock generated by IRC -10414 (the first-ever RSG with an optically detected bow shock) show that the ionization of the wind results in its acceleration by a factor of 2, which reduces the difference between the wind and space velocities of the star and makes the contact discontinuity of the bow shock stable for a range of stellar space velocities and mass-loss rates. Our best-fitting model reproduces the overall shape and surface brightness of the observed bow shock and suggests that the space velocity and mass-loss rate of IRC -10414 are ≈50 km s-1 and ≈10-6 M⊙ yr-1, respectively, and that the number density of the local interstellar medium is ≈3 cm-3. It also shows that the bow shock emission comes mainly from the shocked stellar wind. This naturally explains the enhanced nitrogen abundance in the line-emitting material, derived from the spectroscopy of the bow shock. We found that photoionized bow shocks are ≈15-50 times brighter in optical line emission than their neutral counterparts, from which we conclude that the bow shock of IRC -10414 must be photoionized.

  5. X-ray observation of the shocked red supergiant wind of Cassiopeia A

    International Nuclear Information System (INIS)

    Lee, Jae-Joon; Park, Sangwook; Hughes, John P.; Slane, Patrick O.

    2014-01-01

    Cas A is a Galactic supernova remnant whose supernova explosion is observed to be of Type IIb from spectroscopy of its light echo. Having its SN type known, observational constraints on the mass-loss history of Cas A's progenitor can provide crucial information on the final fate of massive stars. In this paper, we study X-ray characteristics of the shocked ambient gas in Cas A using the 1 Ms observation carried out with the Chandra X-Ray Observatory and try to constrain the mass-loss history of the progenitor star. We identify thermal emission from the shocked ambient gas along the outer boundary of the remnant. Comparison of measured radial variations of spectroscopic parameters of the shocked ambient gas to the self-similar solutions of Chevalier show that Cas A is expanding into a circumstellar wind rather than into a uniform medium. We estimate a wind density n H ∼ 0.9 ± 0.3 cm –3 at the current outer radius of the remnant (∼3 pc), which we interpret as a dense slow wind from a red supergiant (RSG) star. Our results suggest that the progenitor star of Cas A had an initial mass around 16 M ☉ , and its mass before the explosion was about 5 M ☉ , with uncertainties of several tens of percent. Furthermore, the results suggest that, among the mass lost from the progenitor star (∼11 M ☉ ), a significant amount (more than 6 M ☉ ) could have been via its RSG wind.

  6. CHEMICAL ABUNDANCE PATTERNS IN THE INNER GALAXY: THE SCUTUM RED SUPERGIANT CLUSTERS

    International Nuclear Information System (INIS)

    Davies, Ben; Origlia, Livia; Kudritzki, Rolf-Peter; Figer, Don F.; Rich, R. Michael; Najarro, Francisco; Negueruela, Ignacio; Clark, J. Simon

    2009-01-01

    The location of the Scutum Red Supergiant (RSG) clusters at the end of the Galactic Bar makes them an excellent probe of the Galaxy's secular evolution, while the clusters themselves are ideal testbeds in which to study the predictions of stellar evolutionary theory. To this end, we present a study of the RSG's surface abundances using a combination of high-resolution Keck/NIRSPEC H-band spectroscopy and spectral synthesis analysis. We provide abundance measurements for elements C, O, Si, Mg, Ti, and Fe. We find that the surface abundances of the stars studied are consistent with CNO burning and deep, rotationally enhanced mixing. The average α/Fe ratios of the clusters are solar, consistent with a thin-disk population. However, we find significantly subsolar Fe/H ratios for each cluster, a result which strongly contradicts a simple extrapolation of the Galactic metallicity gradient to lower Galactocentric distances. We suggest that a simple one-dimensional parameterization of the Galaxy's abundance patterns is insufficient at low Galactocentric distances, as large azimuthal variations may be present. Indeed, we show that the abundances of O, Si, and Mg are consistent with independent measurements of objects in similar locations in the Galaxy. In combining our results with other data in the literature, we present evidence for large-scale (∼ kpc) azimuthal variations in abundances at Galactocentric distances of 3-5 kpc. While we cannot rule out that this observed behavior is due to systematic offsets between different measurement techniques, we do find evidence for similar behavior in a study of the barred spiral galaxy NGC 4736 which uses homogeneous methodology. We suggest that these azimuthal abundance variations could result from the intense but patchy star formation driven by the potential of the central bar.

  7. THE CHEMICAL ABUNDANCES IN THE GALACTIC CENTER FROM THE ATMOSPHERES OF RED SUPERGIANTS

    International Nuclear Information System (INIS)

    Davies, Ben; Figer, Don F.; Origlia, Livia; Kudritzki, Rolf-Peter; Rich, R. Michael; Najarro, Francisco

    2009-01-01

    The Galactic center (GC) has experienced a high degree of recent star-forming activity, as evidenced by the large number of massive stars currently residing there. The relative abundances of chemical elements in the GC may provide insights into the origins of this activity. Here, we present high-resolution H-band spectra of two red supergiants (RSGs) in the GC (IRS 7 and VR 5-7), and in combination with spectral synthesis we derive abundances for Fe and C, as well as other α-elements Ca, Si, Mg Ti, and O. We find that the C depletion in VR 5-7 is consistent with the predictions of evolutionary models of RSGs, while the heavy depletion of C and O in IRS 7's atmosphere is indicative of deep mixing, possibly due to fast initial rotation and/or enhanced mass loss. Our results indicate that the current surface Fe/H content of each star is slightly above solar. However, comparisons to evolutionary models indicate that the initial Fe-to-H ratio was likely closer to solar, and has been driven higher by H depletion at the stars' surface. Overall, we find α-to-Fe ratios for both stars, which are consistent with the thin Galactic disk. These results are consistent with other chemical studies of the GC, given the precision to which abundances can currently be determined. We argue that the GC abundances are consistent with a scenario in which the recent star-forming activity in the GC was fueled by either material traveling down the Bar from the inner disk, or from the winds of stars in the inner bulge-with no need to invoke top-heavy stellar initial mass functions to explain anomalous abundance ratios.

  8. HD 179821 (V1427 Aql, IRAS 19114+0002) - a massive post-red supergiant star?

    Science.gov (United States)

    Şahin, T.; Lambert, David L.; Klochkova, Valentina G.; Panchuk, Vladimir E.

    2016-10-01

    We have derived elemental abundances of a remarkable star, HD 179821, with unusual composition (e.g. [Na/Fe] = 1.0 ± 0.2 dex) and extra-ordinary spectral characteristics. Its metallicity at [Fe/H] = 0.4 dex places it among the most metal-rich stars yet analysed. The abundance analysis of this luminous star is based on high-resolution and high-quality (S/N ≈ 120-420) optical echelle spectra from McDonald Observatory and Special Astronomy Observatory. The data includes five years of observations over 21 epochs. Standard 1D local thermodynamic equilibrium analysis provides a fresh determination of the atmospheric parameters over all epochs: Teff = 7350 ± 200 K, log g= +0.6 ± 0.3, and a microturbulent velocity ξ = 6.6 ± 1.6 km s-1 and [Fe/H] = 0.4 ± 0.2, and a carbon abundance [C/Fe] = -0.19 ± 0.30. We find oxygen abundance [O/Fe] = -0.25 ± 0.28 and an enhancement of 0.9 dex in N. A supersonic macroturbulent velocity of 22.0 ± 2.0 km s-1 is determined from both strong and weak Fe I and Fe II lines. Elemental abundances are obtained for 22 elements. HD 179821 is not enriched in s-process products. Eu is overabundant relative to the anticipated [X/Fe] ≈ 0.0. Some peculiarities of its optical spectrum (e.g. variability in the spectral line shapes) is noticed. This includes the line profile variations for H α line. Based on its estimated luminosity, effective temperature and surface gravity, HD 179821 is a massive star evolving to become a red supergiant and finally a Type II supernova.

  9. The convective photosphere of the red supergiant CE Tauri. I. VLTI/PIONIER H-band interferometric imaging

    Science.gov (United States)

    Montargès, M.; Norris, R.; Chiavassa, A.; Tessore, B.; Lèbre, A.; Baron, F.

    2018-06-01

    Context. Red supergiant stars are one of the latest stages in the evolution of massive stars. Their photospheric convection may play an important role in the launching mechanism of their mass loss; however, its characteristics and dynamics are still poorly constrained. Aims: By observing red supergiant stars with near infrared interferometry at different epochs, we expect to reveal the evolution of bright convective features on their stellar surface. Methods: We observed the M2Iab-Ib red supergiant star CE Tau with the VLTI/PIONIER instrument in the H band at two different epochs separated by one month. Results: We derive the angular diameter of the star and basic stellar parameters, and reconstruct two reliable images of its H-band photosphere. The contrast of the convective pattern of the reconstructed images is 5 ± 1% and 6 ± 1% for our two epochs of observation. Conclusions: The stellar photosphere shows few changes between the two epochs. The contrast of the convective pattern is below the average contrast variations obtained on 30 randomly chosen snapshots of the best matching 3D radiative hydrodynamics simulation: 23 ± 1% for the original simulation images and 16 ± 1% for the maps degraded to the reconstruction resolution. We offer two hypotheses to explain this observation. CE Tau may be experiencing a quiet convective activity episode or it could be a consequence of its warmer effective temperature (hence its smaller radius) compared to the simulation. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programs 298.D-5005(A) and 298.D-5005(B).Reconstructed images as FITS files and basic stellar parameters are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/614/A12Animated gif of the two epochs is available at http://https://www.aanda.org

  10. Dynamical instability of the envelope of red supergiants and the lower mass limit for carbon detonation supernovae

    International Nuclear Information System (INIS)

    Fujimoto, M.Y.; Nomoto, K.; Sugimoto, D.

    1976-01-01

    The lower mass limit Msub(l) for the carbon detonation supernovae was investigated by testing the dynamical instability of the envelopes of red supergiants. It was found that the dependence of Msub(l) on the mixing length l of convection is appreciable. As a smaller value of l is assumed, Msub(l) becomes larger. It may be as large as 8 solar masses if l is a third of the pressure scale-height. This is one of the ways to remove the difficulty of overproduction of iron-peak elements involved in the model of the carbon detonation supernovae. (Auth.)

  11. Dynamical instability of the envelope of red supergiants and the lower mass limit for carbon detonation supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, M Y [Tokyo Univ. (Japan); Nomoto, K; Sugimoto, D [Tokyo Univ. (Japan). Coll. of General Education

    1976-11-01

    The lower mass limit Msub(l) for the carbon detonation supernovae was investigated by testing the dynamical instability of the envelopes of red supergiants. It was found that the dependence of Msub(l) on the mixing length l of convection is appreciable. As a smaller value of l is assumed, Msub(l) becomes larger. It may be as large as 8 solar masses if l is a third of the pressure scale-height. This is one of the ways to remove the difficulty of overproduction of iron-peak elements involved in the model of the carbon detonation supernovae.

  12. RED SUPERGIANTS AS COSMIC ABUNDANCE PROBES: THE FIRST DIRECT METALLICITY DETERMINATION OF NGC 4038 IN THE ANTENNAE

    International Nuclear Information System (INIS)

    Lardo, C.; Davies, B.; Kudritzki, R-P.; Gazak, J. Z.; Evans, C. J.; Patrick, L. R.; Bergemann, M.; Plez, B.

    2015-01-01

    We present a direct determination of the stellar metallicity in the close pair galaxy NGC 4038 (D = 20 Mpc) based on the quantitative analysis of moderate-resolution KMOS/Very Large Telescope spectra of three super star clusters. The method adopted in our analysis has been developed and optimized to measure accurate metallicities from atomic lines in the J-band of single red supergiant (RSG) or RSG-dominated star clusters. Hence, our metallicity measurements are not affected by the biases and poorly understood systematics inherent to strong line H ii methods, which are routinely applied to massive data sets of galaxies. We find [Z] = +0.07 ± 0.03 and compare our measurements to H ii strong line calibrations. Our abundances and literature data suggest the presence of a flat metallicity gradient, which can be explained as redistribution of metal-rich gas following the strong interaction

  13. An LTE effective temperature scale for red supergiants in the Magellanic clouds

    Science.gov (United States)

    Tabernero, H. M.; Dorda, R.; Negueruela, I.; González-Fernández, C.

    2018-05-01

    We present a self-consistent study of cool supergiants (CSGs) belonging to the Magellanic clouds. We calculated stellar atmospheric parameters using LTE KURUCZ and MARCS atmospheric models for more than 400 individual targets by fitting a careful selection of weak metallic lines. We explore the existence of a Teff scale and its implications in two different metallicity environments (each Magellanic cloud). Critical and in-depth tests have been performed to assess the reliability of our stellar parameters (i.e. internal error budget, NLTE systematics). In addition, several Monte Carlo tests have been carried out to infer the significance of the Teff scale found. Our findings point towards a unique Teff scale that seems to be independent of the environment.

  14. The vast population of Wolf-Rayet and red supergiant stars in M101. I. Motivation and first results

    Energy Technology Data Exchange (ETDEWEB)

    Shara, Michael M.; Bibby, Joanne L.; Zurek, David [Department of Astrophysics, American Museum of Natural History, Central Park West and 79th Street, New York, NY 10024-5192 (United States); Crowther, Paul A. [Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Moffat, Anthony F. J. [Département de Physique, Université de Montréal, CP 6128 Succ. C-V, Montréal, QC H3C 3J7 (Canada); Drissen, Laurent [Département de Physique, Université Laval, Pavillon Vachon, Quebec City, QC G1K 7P4 (Canada)

    2013-12-01

    Assembling a catalog of at least 10,000 Wolf-Rayet (W-R) stars is an essential step in proving (or disproving) that these stars are the progenitors of Type Ib and Type Ic supernovae. To this end, we have used the Hubble Space Telescope (HST) to carry out a deep, He II optical narrowband imaging survey of the ScI spiral galaxy M101. Almost the entire galaxy was imaged with the unprecedented depth and resolution that only the HST affords. Differenced with archival broadband images, the narrowband images allow us to detect much of the W-R star population of M101. We describe the extent of the survey and our images, as well as our data reduction procedures. A detailed broadband-narrowband imaging study of a field east of the center of M101, containing the giant star-forming region NGC 5462, demonstrates our completeness limits, how we find W-R candidates, their properties and spatial distribution, and how we rule out most contaminants. We use the broadband images to locate luminous red supergiant (RSG) candidates. The spatial distributions of the W-R and RSG stars near NGC 5462 are strikingly different. W-R stars dominate the complex core, while RSGs dominate the complex halo. Future papers in this series will describe and catalog more than a thousand W-R and RSG candidates that are detectable in our images, as well as spectra of many of those candidates.

  15. MASER OBSERVATIONS OF WESTERLUND 1 AND COMPREHENSIVE CONSIDERATIONS ON MASER PROPERTIES OF RED SUPERGIANTS ASSOCIATED WITH MASSIVE CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Fok, Thomas K. T.; Nakashima, Jun-ichi; Yung, Bosco H. K.; Hsia, Chih-Hao [Department of Physics, University of Hong Kong, Pokfulam Road (Hong Kong); Deguchi, Shuji, E-mail: junichi@hku.hk [Nobeyama Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Minamisaku, Nagano 384-1305 (Japan)

    2012-11-20

    We report the results of Australia Telescope Compact Array observations of the Westerlund 1 (Wd1) region in the SiO v = 1, J = 1-0, and H{sub 2}O 6{sub 16}-5{sub 23} maser lines, and we also report the analysis of maser properties of red supergiants (RSGs) associated with six massive clusters including Wd1. The primary purpose of this research is to explore possibilities of using maser emission for investigating the nature of massive clusters and associated RSGs. The SiO v = 1, J = 1-0, and H{sub 2}O 6{sub 16}-5{sub 23} maser lines are detected toward two of four known RSGs in Wd1. The large velocity ranges of maser emission are consistent with the RSG status. RSGs with maser emission tend to exhibit redder log (F {sub 21}/F {sub 12}) and [K-12.13] colors compared to RSGs with no maser emission. The mass-loss rates derived from dust radiative transfer modeling suggest that RSGs with maser emission tend to exhibit larger mass-loss rates compared to RSGs with no maser emission. In an extended sample of 57 RSGs in six massive clusters, detections in the SiO line tend to homogeneously distribute in absolute luminosity L, whereas those in the H{sub 2}O line tend to distribute in a region with large L values.

  16. Evolutionary Models of Red Supergiants: Evidence for A Metallicity-dependent Mixing Length and Implications for Type IIP Supernova Progenitors

    Science.gov (United States)

    Chun, Sang-Hyun; Yoon, Sung-Chul; Jung, Moo-Keon; Kim, Dong Uk; Kim, Jihoon

    2018-01-01

    Recent studies on the temperatures of red supergiants (RSGs) in the local universe provide us with an excellent observational constraint on RSG models. We calibrate the mixing length parameter by comparing model predictions with the empirical RSG temperatures in Small and Large Magellanic Clouds, Milky Way, and M31, which are inferred from the TiO band and the spectral energy distribution (SED). Although our RSG models are computed with the MESA code, our result may be applied to other stellar evolution codes, including the BEC and TWIN codes. We find evidence that the mixing length increases with increasing metallicity for both cases where the TiO and SED temperatures of RSGs are used for the calibration. Together with the recent finding of a similar correlation in low-mass red giants by Tayar et al., this implies that the metallicity dependence of the mixing length is a universal feature in post-main sequence stars of both low and high masses. Our result implies that typical Type IIP supernova (SN IIP) progenitors with initial masses of ∼ 10{--}16 {M}ȯ have a radius range of 400 {R}ȯ ≲ R≲ 800 {R}ȯ regardless of metallicity. As an auxiliary result of this study, we find that the hydrogen-rich envelope mass of SN IIP progenitors for a given initial mass is predicted to be largely independent of metallicity if the Ledoux criterion with slow semiconvection is adopted, while the Schwarzschild models predict systematically more massive hydrogen-rich envelopes for lower metallicity.

  17. Photometry of the Variable Bright Red Supergiant Betelgeuse from the Ground and from Space with the BRITE Nano-satellites

    Science.gov (United States)

    Minor, Robert; Guinan, Edward F.

    2016-01-01

    Robert B. Minor, Edward Guinan, Richard Wasatonic Betelgeuse (Alpha Orionis) is a large, luminous semi-regular red supergiant of spectral class M1.5-2Iab. It is the 8th brightest star in the night sky. Betelgeuse is 30,000 times more luminous than the Sun and 700 times larger. It has an estimated age of ~8 +/- 2 Myr. Betelgeuse explode in a Type II supernova (anytime within the next million years). When it explodes, it will shine with about the intensity of a full moon and may be visible during the day. However, it is too far away to cause any major damage to Earth. Photometry of this pre-supernova star has been ongoing at Villanova for nearly 45 years. These observations are being used to define the complex brightness variations of this star. Semi-regular periodic light variations have been found with periods of 385 days up to many years. These light variations are used to study its unstable atmosphere and resulting complex pulsations. Over the last 15 years, it has been observed by Wasatonic who has accumulated a large photometric database. The ground-based observations are limited to precisions of 1.5%, and due to poor weather, limit observations to about 1-2 times per week. However, with the recent successful launch of the BRITE Nano-satellites (http://www.brite-constellation.at) during 2013-14, it is possible to secure high precision photometry of bright stars, including Betelgeuse, continuously for up to 3 months. Villanova has participated in the BRITE guest investigators program and has been awarded observing time and data rights many bright stars, including Betelgeuse. BRITE blue and red observations of Betelgeuse were carried out during the Nov-Feb 2013-14 season and the 2014-15. These datasets were given to Villanova and have been combined with coexistent photometry from Wasatonic. Although BRITE's red data is saturated, the blue data is useable. The BRITE datasets were combined with our ground-based V, red, and near-IR photometry. Problems were

  18. ALMA observations of anisotropic dust mass loss in the inner circumstellar environment of the red supergiant VY Canis Majoris

    Science.gov (United States)

    O'Gorman, E.; Vlemmings, W.; Richards, A. M. S.; Baudry, A.; De Beck, E.; Decin, L.; Harper, G. M.; Humphreys, E. M.; Kervella, P.; Khouri, T.; Muller, S.

    2015-01-01

    The processes leading to dust formation and the subsequent role it plays in driving mass loss in cool evolved stars is an area of intense study. Here we present high resolution ALMA Science Verification data of the continuum emission around the highly evolved oxygen-rich red supergiant VY CMa. These data enable us to study the dust in its inner circumstellar environment at a spatial resolution of 129 mas at 321 GHz and 59 mas at 658 GHz, thus allowing us to trace dust on spatial scales down to 11 R⋆ (71 AU). Two prominent dust components are detected and resolved. The brightest dust component, C, is located 334 mas (61 R⋆) southeast of the star and has a dust mass of at least 2.5 × 10-4 M⊙. It has a dust emissivity spectral index of β = -0.1 at its peak, implying that it is optically thick at these frequencies with a cool core of Td ≲ 100 K. Interestingly, not a single molecule in the ALMA data has emission close to the peak of this massive dust clump. The other main dust component, VY, is located at the position of the star and contains a total dust mass of 4.0 × 10-5 M⊙. It also contains a weaker dust feature extending over 60 R⋆ to the north with the total component having a typical dust emissivity spectral index of β = 0.7. We find that at least 17% of the dust mass around VY CMa is located in clumps ejected within a more quiescent roughly spherical stellar wind, with a quiescent dust mass loss rate of 5 × 10-6 M⊙yr-1. The anisotropic morphology of the dust indicates a continuous, directed mass loss over a few decades, suggesting that this mass loss cannot be driven by large convection cells alone. Appendices are available in electronic form at http://www.aanda.org

  19. Fundamental properties and atmospheric structure of the red supergiant VY Canis Majoris based on VLTI/AMBER spectro-interferometry

    Science.gov (United States)

    Wittkowski, M.; Hauschildt, P. H.; Arroyo-Torres, B.; Marcaide, J. M.

    2012-04-01

    Aims: We investigate the atmospheric structure and fundamental properties of the red supergiant VY CMa. Methods: We obtained near-infrared spectro-interferometric observations of VY CMa with spectral resolutions of 35 and 1500 using the AMBER instrument at the VLTI. Results: The visibility data indicate the presence of molecular layers of water vapor and CO in the extended atmosphere with an asymmetric morphology. The uniform disk diameter in the water band around 2.0 μm is increased by ~20% compared to the near-continuum bandpass at 2.20-2.25 μm, and in the CO band at 2.3-2.5 μm it is increased by up to ~50%. The closure phases indicate relatively small deviations from point symmetry close to the photospheric layer, and stronger deviations in the extended H2O and CO layers. Making use of the high spatial and spectral resolution, a near-continuum bandpass can be isolated from contamination by molecular and dusty layers, and the Rosseland-mean photospheric angular diameter is estimated to 11.3 ± 0.3 mas based on a PHOENIX atmosphere model. Together with recent high-precision estimates of the distance and spectro-photometry, this estimate corresponds to a radius of 1420 ± 120 R⊙ and an effective temperature of 3490 ± 90 K. Conclusions: VY CMa exhibits asymmetric, possibly clumpy, atmospheric layers of H2O and CO, which are not co-spatial, within a larger elongated dusty envelope. Our revised fundamental parameters put VY CMa close to the Hayashi limit of recent evolutionary tracks of initial mass 25 M⊙ with rotation or 32 M⊙ without rotation, shortly before evolving blueward in the HR-diagram. Based on observations made with the VLT Interferometer (VLTI) at Paranal Observatory under programme ID 386.D-0012.Figures 2, 3 and 5 are available in electronic form at http://www.aanda.org

  20. VizieR Online Data Catalog: Observed red supergiants in the inner Galaxy (Messineo+, 2016)

    Science.gov (United States)

    Messineo, M.; Zhu, Q.; Menten, K. M.; Ivanov, V. D.; Figer, D. F.; Kudritzki, R.-P.; Rosie, Chen C.-H.

    2018-02-01

    Spectroscopic observations were carried out with the Son of ISAAC (SofI; Moorwood et al. 1998Msngr..91....9M) Spectrograph on the ESO/New Technology Telescope (NTT) 3.58 m telescope of the La Silla Observatory, on the three nights from UT 2015 June 16 to 19-program ID 095.D-0252(A). Spectra with the low-resolution red grism, and the 0.6" wide slit, delivering resolution R~980 over the wavelength range λ=1.53-2.52 μm were obtained for 94 targets. For each target a minimum number of four exposures, nodded along the slit, were taken in an ABBA sequence. Typical integration times per frame ranged from 2 to 100 s (DITsxNDITs). (1 data file).

  1. Magnetically aligned dust and SiO maser polarisation in the envelope of the red supergiant VY Canis Majoris

    Science.gov (United States)

    Vlemmings, W. H. T.; Khouri, T.; Martí-Vidal, I.; Tafoya, D.; Baudry, A.; Etoka, S.; Humphreys, E. M. L.; Jones, T. J.; Kemball, A.; O'Gorman, E.; Pérez-Sánchez, A. F.; Richards, A. M. S.

    2017-07-01

    Aims: Polarisation observations of circumstellar dust and molecular (thermal and maser) lines provide unique information about dust properties and magnetic fields in circumstellar envelopes of evolved stars. Methods: We use Atacama Large Millimeter/submillimeter Array (ALMA) Band 5 science verification observations of the red supergiant VY CMa to study the polarisation of SiO thermal/maser lines and dust continuum at 1.7 mm wavelength. We analyse both linear and circular polarisation and derive the magnetic field strength and structure, assuming the polarisation of the lines originates from the Zeeman effect, and that of the dust originates from aligned dust grains. We also discuss other effects that could give rise to the observed polarisation. Results: We detect, for the first time, significant polarisation ( 3%) of the circumstellar dust emission at millimeter wavelengths. The polarisation is uniform with an electric vector position angle of 8°. Varying levels of linear polarisation are detected for the J = 4 - 328SiO v = 0, 1, 2, and 29SiO v = 0, 1 lines, with the strongest polarisation fraction of 30% found for the 29SiO v = 1 maser. The linear polarisation vectors rotate with velocity, consistent with earlier observations. We also find significant (up to 1%) circular polarisation in several lines, consistent with previous measurements. We conclude that the detection is robust against calibration and regular instrumental errors, although we cannot yet fully rule out non-standard instrumental effects. Conclusions: Emission from magnetically aligned grains is the most likely origin of the observed continuum polarisation. This implies that the dust is embedded in a magnetic field >13 mG. The maser line polarisation traces the magnetic field structure. The magnetic field in the gas and dust is consistent with an approximately toroidal field configuration, but only higher angular resolution observations will be able to reveal more detailed field structure. If the

  2. SN 2016X: a type II-P supernova with a signature of shock breakout from explosion of a massive red supergiant

    Science.gov (United States)

    Huang, F.; Wang, X.-F.; Hosseinzadeh, G.; Brown, P. J.; Mo, J.; Zhang, J.-J.; Zhang, K.-C.; Zhang, T.-M.; Howell, D.-A.; Arcavi, I.; McCully, C.; Valenti, S.; Rui, L.-M.; Song, H.; Xiang, D.-F.; Li, W.-X.; Lin, H.; Wang, L.-F.

    2018-04-01

    We present extensive ultraviolet (UV) and optical photometry, as well as dense optical spectroscopy, for type II Plateau (IIP) supernova SN 2016X that exploded in the nearby (˜15 Mpc) spiral galaxy UGC 08041. The observations span the period from 2 to 180 d after the explosion; in particular, the Swift UV data probably captured the signature of shock breakout associated with the explosion of SN 2016X. It shows very strong UV emission during the first week after explosion, with a contribution of ˜20-30 per cent to the bolometric luminosity (versus ≲15 per cent for normal SNe IIP). Moreover, we found that this supernova has an unusually long rise time of about 12.6 ± 0.5 d in the R band (versus ˜7.0 d for typical SNe IIP). The optical light curves and spectral evolution are quite similar to the fast-declining type IIP object SN 2013ej, except that SN 2016X has a relatively brighter tail. Based on the evolution of photospheric temperature as inferred from the Swift data in the early phase, we derive that the progenitor of SN 2016X has a radius of about 930 ± 70 R⊙. This large-size star is expected to be a red supergiant star with an initial mass of ≳19-20 M⊙ based on the mass-radius relation of the Galactic red supergiants, and it represents one of the most largest and massive progenitors found for SNe IIP.

  3. Surface Magnetic Fields on Giants and Supergiants

    Science.gov (United States)

    Lebre, Agnès

    2018-04-01

    After a short introduction to spectropolarimetry and the tecnics allowing for the detection of surface fields, I will review the numerous and various detections of magnetic fields at the surface of giant and supergiant stars. On Betelgeuse, the prototype of Red Supergiants, I will present recent results collected after a 10 years long spectropolarimetric survey.

  4. Red Supergiants as Potential Type IIn Supernova Progenitors: Spatially Resolved 4.6 μm CO Emission Around VY CMa and Betelgeuse

    Science.gov (United States)

    Smith, Nathan; Hinkle, Kenneth H.; Ryde, Nils

    2009-03-01

    We present high-resolution 4.6 μm CO spectra of the circumstellar environments of two red supergiants (RSGs) that are potential supernova (SN) progenitors: Betelgeuse and VY Canis Majoris (VY CMa). Around Betelgeuse, 12CO emission within ±3'' (±12 km s-1) follows a mildly clumpy but otherwise spherical shell, smaller than its ~55'' shell in K I λ7699. In stark contrast, 4.6 μm CO emission around VY CMa is coincident with bright K I in its clumpy asymmetric reflection nebula, within ±5'' (±40 km s-1) of the star. Our CO data reveal redshifted features not seen in K I spectra of VY CMa, indicating a more isotropic distribution of gas punctuated by randomly distributed asymmetric clumps. The relative CO and K I distribution in Betelgeuse arises from ionization effects within a steady wind, whereas in VY CMa, K I is emitted from skins of CO cloudlets resulting from episodic mass ejections 500-1000 yr ago. In both cases, CO and K I trace potential pre-SN circumstellar matter: we conclude that an extreme RSG like VY CMa might produce a Type IIn event like SN 1988Z if it were to explode in its current state, but Betelgeuse will not. VY CMa demonstrates that luminous blue variables are not necessarily the only progenitors of SNe IIn, but it underscores the requirement that SNe IIn suffer enhanced episodic mass loss shortly before exploding. Based on observations obtained at the Gemini Observatory.

  5. THE MASS-LOSS RETURN FROM EVOLVED STARS TO THE LARGE MAGELLANIC CLOUD. IV. CONSTRUCTION AND VALIDATION OF A GRID OF MODELS FOR OXYGEN-RICH AGB STARS, RED SUPERGIANTS, AND EXTREME AGB STARS

    International Nuclear Information System (INIS)

    Sargent, Benjamin A.; Meixner, M.; Srinivasan, S.

    2011-01-01

    To measure the mass loss from dusty oxygen-rich (O-rich) evolved stars in the Large Magellanic Cloud (LMC), we have constructed a grid of models of spherically symmetric dust shells around stars with constant mass-loss rates using 2Dust. These models will constitute the O-rich model part of the 'Grid of Red supergiant and Asymptotic giant branch star ModelS' (GRAMS). This model grid explores four parameters-stellar effective temperature from 2100 K to 4700 K; luminosity from 10 3 to 10 6 L sun ; dust shell inner radii of 3, 7, 11, and 15 R star ; and 10.0 μm optical depth from 10 -4 to 26. From an initial grid of ∼1200 2Dust models, we create a larger grid of ∼69,000 models by scaling to cover the luminosity range required by the data. These models are available online to the public. The matching in color-magnitude diagrams and color-color diagrams to observed O-rich asymptotic giant branch (AGB) and red supergiant (RSG) candidate stars from the SAGE and SAGE-Spec LMC samples and a small sample of OH/IR stars is generally very good. The extreme AGB star candidates from SAGE are more consistent with carbon-rich (C-rich) than O-rich dust composition. Our model grid suggests lower limits to the mid-infrared colors of the dustiest AGB stars for which the chemistry could be O-rich. Finally, the fitting of GRAMS models to spectral energy distributions of sources fit by other studies provides additional verification of our grid and anticipates future, more expansive efforts.

  6. Red alert. The worldwide dangers of nuclear power

    Energy Technology Data Exchange (ETDEWEB)

    Cook, J

    1986-01-01

    The book 'Red Alert' considers the problems and hazards of nuclear power. The politics behind the nuclear power programmes in the United Kingdom and other countries are examined, along with the sequence of events in Britain which led to the building of the Magnox and Advanced Gas-Cooled nuclear reactors. Health hazards of radiation, radioactive waste management, nuclear weapons programmes, and radiation accidents including the Chernobyl accident, are also discussed. (U.K.).

  7. Long-period variables in the Magellanic Clouds: Supergiants, AGB stars, supernova precursors, planetary nebula precursors, and enrichment of the interstellar medium

    International Nuclear Information System (INIS)

    Wood, P.; Bessell, M.S.; Fox, M.W.

    1983-01-01

    Infrared JHK magnitudes and low-dispersion red spectra have been obtained for 90 long-period variables (LPVs) in the Small and Large Magellanic Clouds. The LPVs fall into two distinct groups, core helium (or carbon) burning supergiants and stars on the asymptotic giant branch (AGB). The supergiants have small pulsation amplitudes in K ( or approx. =5 M/sub sun/ produce supernovae while less massive stars produce planetary nebulae with nebula masses from approx.0.1--2.1 M/sub sun/. The coreburning red supergiants appear highly overluminous for their pulsation mass, indicating that they have lost up to half their mass since the main-sequence phase

  8. Yellow supergiants in open clusters

    International Nuclear Information System (INIS)

    Sowell, J.R.

    1986-01-01

    Superluminous giant stars (SLGs) have been reported in young globular clusters in the Large Magellanic Cloud (LMC). These stars appear to be in the post-asymptotic-giant-branch phase of evolution. This program was an investigation of galactic SLG candidates in open clusters, which are more like the LMC young globular clusters. These were chosen because luminosity, mass, and age determinations can be made for members since cluster distances and interstellar reddenings are known. Color magnitude diagrams were searched for candidates, using the same selection criteria as for SLGs in the LMC. Classification spectra were obtained of 115 program stars from McGraw-Hill Observatory and of 68 stars from Cerro Tololo Inter-American Observatory Chile. These stars were visually classified on the MK system using spectral scans of standard stars taken at the respective observations. Published information was combined with this program's data for 83 stars in 30 clusters. Membership probabilities were assigned to these stars, and the clusters were analyzed according to age. It was seen that the intrinsically brightest supergiants are found in the youngest clusters. With increasing cluster age, the absolute luminosities attained by the supergiants decline. Also, it appears that the evolutionary tracks of luminosity class II stars are more similar to those of class I than of class III

  9. Mass loss from OB supergiants in x-ray binary systems

    International Nuclear Information System (INIS)

    Alme, M.L.; Wilson, J.R.

    1975-01-01

    A study of the atmospheres of OB supergiants in x-ray binary systems indicates that when the stellar surface is close enough to the saddle in the gravitational potential to provide a mass transfer rate adequate to power a compact x-ray source, large-amplitude variations in the rate of mass flow occur. 9 references

  10. Line profile variability in B supergiants

    Czech Academy of Sciences Publication Activity Database

    Tomić, S.; Kraus, Michaela; Atanacković, O.

    2017-01-01

    Roč. 96, č. 1 (2017), s. 161-166 ISSN 0373-3742. [National Conference of Astronomers of Serbia /17./. Belgrade, 23.09.2014-27.09.2014] R&D Projects: GA ČR(CZ) GA14-21373S; GA MŠk LG14013 Institutional support: RVO:67985815 Keywords : supergiants * variability * macroturbulenc Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science)

  11. CNO abundances in Cepheids and supergiants: theoretical implications

    International Nuclear Information System (INIS)

    Becker, S.A.; Cox, A.N.

    1982-01-01

    Models of a 9 M/sub sun/ star have been evolved to see if the observed nitrogen enhancement and the carbon and oxygen depletions in yellow supergiants and Cepheids can be explained. In the standard (first dredge-up phase) evolutionary picture, the normal or near normal CNO abundances for the envelopes of stars on the main sequence are altered when such stars become red giants with deeply mixed convective envelopes prior to core He ignition. While this process does result in a noticeable nitrogen enhancement and a carbon reduction (oxygen is only slightly reduced), the observed changes in the CNO abundances are reported to be much larger. Consequently, other additional mechanisms need to be considered. The effects of primordial abundances, mass loss and transfer, convective overshoot, rotation, and magnetic fields are discussed. It is found that in order to explain the observed O depletion, there must be some form of mixing between the convective hydrogen-burning core and the inner part of the radiative envelope. This additional mixed material is then latter dredged up during the red giant phase. A simplified three-zone model is proposed. Finally, as a consequence of this additional mixing, longer main-sequence lifetimes and more luminous blue loops in the Cepheid region are predicted

  12. LBT Discovery of a Yellow Supergiant Eclipsing Binary in the Dwarf Galaxy Holmberg IX

    Science.gov (United States)

    Prieto, J. L.; Stanek, K. Z.; Kochanek, C. S.; Weisz, D. R.; Baruffolo, A.; Bechtold, J.; Burwitz, V.; De Santis, C.; Gallozzi, S.; Garnavich, P. M.; Giallongo, E.; Hill, J. M.; Pogge, R. W.; Ragazzoni, R.; Speziali, R.; Thompson, D. J.; Wagner, R. M.

    2008-01-01

    In a variability survey of M81 using the Large Binocular Telescope we have discovered a peculiar eclipsing binary (MV ~ - 7.1) in the field of the dwarf galaxy Holmberg IX. It has a period of 271 days, and the light curve is well fit by an overcontact model in which both stars are overflowing their Roche lobes. It is composed of two yellow supergiants (V - Isimeq 1 mag, Teffsimeq 4800 K), rather than the far more common red or blue supergiants. Such systems must be rare. While we failed to find any similar systems in the literature, we did, however, note a second example. The SMC F0 supergiant R47 is a bright (MV ~ - 7.5) periodic variable whose All Sky Automated Survey (ASAS) light curve is well fit as a contact binary with a 181 day period. We propose that these systems are the progenitors of supernovae like SN 2004et and SN 2006ov, which appeared to have yellow progenitors. The binary interactions (mass transfer, mass loss) limit the size of the supergiant to give it a higher surface temperature than an isolated star at the same core evolutionary stage. We also discuss the possibility of this variable being a long-period Cepheid. Based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in the United States, Italy and Germany. LBT Corporation partners are The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.

  13. Effect of Divalent Cations on RED Performance and Cation Exchange Membrane Selection to Enhance Power Densities.

    Science.gov (United States)

    Rijnaarts, Timon; Huerta, Elisa; van Baak, Willem; Nijmeijer, Kitty

    2017-11-07

    Reverse electrodialysis (RED) is a membrane-based renewable energy technology that can harvest energy from salinity gradients. The anticipated feed streams are natural river and seawater, both of which contain not only monovalent ions but also divalent ions. However, RED using feed streams containing divalent ions experiences lower power densities because of both uphill transport and increased membrane resistance. In this study, we investigate the effects of divalent cations (Mg 2+ and Ca 2+ ) on RED and demonstrate the mitigation of those effects using both novel and existing commercial cation exchange membranes (CEMs). Monovalent-selective Neosepta CMS is known to block divalent cations transport and can therefore mitigate reductions in stack voltage. The new multivalent-permeable Fuji T1 is able to transport divalent cations without a major increase in resistance. Both strategies significantly improve power densities compared to standard-grade CEMs when performing RED using streams containing divalent cations.

  14. Minimal RED Cell Pairs Markedly Improve Electrode Kinetics and Power Production in Microbial Reverse Electrodialysis Cells

    KAUST Repository

    Cusick, Roland D.

    2013-12-17

    Power production from microbial reverse electrodialysis cell (MRC) electrodes is substantially improved compared to microbial fuel cells (MFCs) by using ammonium bicarbonate (AmB) solutions in multiple RED cell pair stacks and the cathode chamber. Reducing the number of RED membranes pairs while maintaining enhanced electrode performance could help to reduce capital costs. We show here that using only a single RED cell pair (CP), created by operating the cathode in concentrated AmB, dramatically increased power production normalized to cathode area from both acetate (Acetate: from 0.9 to 3.1 W/m 2-cat) and wastewater (WW: 0.3 to 1.7 W/m2), by reducing solution and charge transfer resistances at the cathode. A second RED cell pair increased RED stack potential and reduced anode charge transfer resistance, further increasing power production (Acetate: 4.2 W/m2; WW: 1.9 W/m2). By maintaining near optimal electrode power production with fewer membranes, power densities normalized to total membrane area for the 1-CP (Acetate: 3.1 W/m2-mem; WW: 1.7 W/m2) and 2-CP (Acetate: 1.3 W/m2-mem; WW: 0.6 W/m2) reactors were much higher than previous MRCs (0.3-0.5 W/m2-mem with acetate). While operating at peak power, the rate of wastewater COD removal, normalized to reactor volume, was 30-50 times higher in 1-CP and 2-CP MRCs than that in a single chamber MFC. These findings show that even a single cell pair AmB RED stack can significantly enhance electrical power production and wastewater treatment. © 2013 American Chemical Society.

  15. Minimal RED Cell Pairs Markedly Improve Electrode Kinetics and Power Production in Microbial Reverse Electrodialysis Cells

    KAUST Repository

    Cusick, Roland D.; Hatzell, Marta; Zhang, Fang; Logan, Bruce E.

    2013-01-01

    Power production from microbial reverse electrodialysis cell (MRC) electrodes is substantially improved compared to microbial fuel cells (MFCs) by using ammonium bicarbonate (AmB) solutions in multiple RED cell pair stacks and the cathode chamber. Reducing the number of RED membranes pairs while maintaining enhanced electrode performance could help to reduce capital costs. We show here that using only a single RED cell pair (CP), created by operating the cathode in concentrated AmB, dramatically increased power production normalized to cathode area from both acetate (Acetate: from 0.9 to 3.1 W/m 2-cat) and wastewater (WW: 0.3 to 1.7 W/m2), by reducing solution and charge transfer resistances at the cathode. A second RED cell pair increased RED stack potential and reduced anode charge transfer resistance, further increasing power production (Acetate: 4.2 W/m2; WW: 1.9 W/m2). By maintaining near optimal electrode power production with fewer membranes, power densities normalized to total membrane area for the 1-CP (Acetate: 3.1 W/m2-mem; WW: 1.7 W/m2) and 2-CP (Acetate: 1.3 W/m2-mem; WW: 0.6 W/m2) reactors were much higher than previous MRCs (0.3-0.5 W/m2-mem with acetate). While operating at peak power, the rate of wastewater COD removal, normalized to reactor volume, was 30-50 times higher in 1-CP and 2-CP MRCs than that in a single chamber MFC. These findings show that even a single cell pair AmB RED stack can significantly enhance electrical power production and wastewater treatment. © 2013 American Chemical Society.

  16. BVR PHOTOMETRY OF SUPERGIANT STARS IN HOLMBERG II

    Directory of Open Access Journals (Sweden)

    Y.-J. Sohn

    2006-03-01

    Full Text Available We report the photometric properties in BVR bands for the resolved bright supergiant stars in the dwarf galaxy Holmberg II. The color-magnitude diagrams and color-color diagram of 374 resolved stars indicate that the majority of the member stars are supergiant stars with a wide range of spectral type between B-K. A comparison with theoretical evolutionary tracks indicates that the supergiant stars in the observed field have progenitor masses between ~10M_⨀ and 20M_⨀. The exponent of luminosity function in V is in good agreement with those of the Small and Large Magellanic Clouds.

  17. A DARK ENERGY CAMERA SEARCH FOR MISSING SUPERGIANTS IN THE LMC AFTER THE ADVANCED LIGO GRAVITATIONAL-WAVE EVENT GW150914

    Energy Technology Data Exchange (ETDEWEB)

    Annis, J.; Soares-Santos, M.; Diehl, H. T.; Drlica-Wagner, A.; Finley, D. A.; Flaugher, B.; Frieman, J.; Herner, K. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Berger, E.; Cowperthwaite, P. S.; Drout, M. R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Brout, D. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Chen, H.; Doctor, Z.; Farr, B.; Holz, D.; Kessler, R. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Chornock, R. [Astrophysical Institute, Department of Physics and Astronomy, Ohio University, 251B Clippinger Lab, Athens, OH 45701 (United States); Foley, R. J.; Gruendl, R. A. [Department of Astronomy, University of Illinois, 1002 W. Green Street, Urbana, IL 61801 (United States); Collaboration: DES Collaboration; and others

    2016-06-01

    The collapse of a stellar core is expected to produce gravitational waves (GWs), neutrinos, and in most cases a luminous supernova. Sometimes, however, the optical event could be significantly less luminous than a supernova and a direct collapse to a black hole, where the star just disappears, is possible. The GW event GW150914 was detected by the LIGO Virgo Collaboration via a burst analysis that gave localization contours enclosing the Large Magellanic Cloud (LMC). Shortly thereafter, we used DECam to observe 102 deg{sup 2} of the localization area, including 38 deg{sup 2} on the LMC for a missing supergiant search. We construct a complete catalog of LMC luminous red supergiants, the best candidates to undergo invisible core collapse, and collected catalogs of other candidates: less luminous red supergiants, yellow supergiants, blue supergiants, luminous blue variable stars, and Wolf–Rayet stars. Of the objects in the imaging region, all are recovered in the images. The timescale for stellar disappearance is set by the free-fall time, which is a function of the stellar radius. Our observations at 4 and 13 days after the event result in a search sensitive to objects of up to about 200 solar radii. We conclude that it is unlikely that GW150914 was caused by the core collapse of a relatively compact supergiant in the LMC, consistent with the LIGO Collaboration analyses of the gravitational waveform as best interpreted as a high mass binary black hole merger. We discuss how to generalize this search for future very nearby core-collapse candidates.

  18. A Dark Energy Camera Search for Missing Supergiants in the LMC After the Advanced LIGO Gravitational-Wave Event GW150914

    Science.gov (United States)

    Annis, J.; Soares-Santos, M.; Berger, E.; Brout, D.; Chen, H.; Chornock, R.; Cowperthwaite, P. S.; Diehl, H. T.; Doctor, Z.; Cenko, S. B.

    2016-01-01

    The collapse of a stellar core is expected to produce gravitational waves (GWs), neutrinos, and in most cases a luminous supernova. Sometimes, however, the optical event could be significantly less luminous than a supernova and a direct collapse to a black hole, where the star just disappears, is possible. The GW event GW150914 was detected by the LIGO Virgo Collaboration via a burst analysis that gave localization contours enclosing the Large Magellanic Cloud (LMC). Shortly thereafter, we used DECam to observe 102 deg(exp.2) of the localization area,including 38 deg(exp. 2) on the LMC for a missing supergiant search. We construct a complete catalog of LMC luminous red supergiants, the best candidates to undergo invisible core collapse, and collected catalogs of other candidates:less luminous red supergiants, yellow supergiants, blue supergiants, luminous blue variable stars, and Wolf-Rayet stars. Of the objects in the imaging region, all are recovered in the images. The timescale for stellar disappearance is set by the free-fall time, which is a function of the stellar radius. Our observations at 4 and 13 days after the event result in a search sensitive to objects of up to about 200 solar radii. We conclude that it is unlikely that GW150914 was caused by the core collapse of a relatively compact supergiant in the LMC, consistent with the LIGO Collaboration analyses of the gravitational waveform as best interpreted as a high mass binary black hole merger. We discuss how to generalize this search for future very nearby core-collapse candidates.

  19. PHOTOSPHERIC VARIATIONS OF THE SUPERGIANT γ Cyg

    International Nuclear Information System (INIS)

    Gray, David F.

    2010-01-01

    New high-resolution spectroscopic observations of the supergiant γ Cyg (F8 Iab) taken between 2000 and 2008 consistently show strongly reversed-C-shaped bisectors for all unblended spectral lines. Small-amplitude variations in radial velocity and line shapes occur in an irregular manner with time scales ∼100 days and longer. The radial velocities occasionally show changes as large as 2 km s -1 , but much smaller changes are going on continuously. Differential line bisectors show shape changes and Doppler displacement characteristic of radial expansion and contraction. These might arise from non-periodic radial pulsation-like motions or from the appearance of giant convection cells that occupy most of the visible hemisphere of the star. Line-depth ratios are correlated with the line shifts on a seasonal basis and indicate temperature changes ranging up to ∼15 K, with larger temperature occurring during times of most rapid contraction.

  20. Unveiling the evolutionary phase of B[e] supergiants

    Czech Academy of Sciences Publication Activity Database

    Muratore, M.F.; Kraus, Michaela; Liermann, A.; Schnurr, O.; Cidale, L.S.; Arias, M.L.

    2010-01-01

    Roč. 53, - (2010), s. 123-126 E-ISSN 1669-9521 Institutional research plan: CEZ:AV0Z10030501 Keywords : B[e] supergiants * K-band spectra Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  1. On minimally parametric primordial power spectrum reconstruction and the evidence for a red tilt

    International Nuclear Information System (INIS)

    Verde, Licia; Peiris, Hiranya

    2008-01-01

    The latest cosmological data seem to indicate a significant deviation from scale invariance of the primordial power spectrum when parameterized either by a power law or by a spectral index with non-zero 'running'. This deviation, by itself, serves as a powerful tool for discriminating among theories for the origin of cosmological structures such as inflationary models. Here, we use a minimally parametric smoothing spline technique to reconstruct the shape of the primordial power spectrum. This technique is well suited to searching for smooth features in the primordial power spectrum such as deviations from scale invariance or a running spectral index, although it would recover sharp features of high statistical significance. We use the WMAP three-year results in combination with data from a suite of higher resolution cosmic microwave background experiments (including the latest ACBAR 2008 release), as well as large-scale structure data from SDSS and 2dFGRS. We employ cross-validation to assess, using the data themselves, the optimal amount of smoothness in the primordial power spectrum consistent with the data. This minimally parametric reconstruction supports the evidence for a power law primordial power spectrum with a red tilt, but not for deviations from a power law power spectrum. Smooth variations in the primordial power spectrum are not significantly degenerate with the other cosmological parameters

  2. Self Powered Non-Dispersive Infra-Red CO{sub 2} Gas Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, D R; MacGregor, C, E-mail: des@gassensing.co.uk [Gas Sensing Solutions Ltd, 60 Grayshill Road, Westfield North Courtyard, Glasgow G68 9HQ (United Kingdom)

    2011-08-17

    This paper describes a non-dispersive infra-red CO{sub 2} gas sensor, incorporating a mid-infra-red solid state light source/ detector combination, tuned to match the spectral absorption characteristic of CO{sub 2} gas. Injection moulded optics provide low cost manufacture. Continuous operation power consumption is < 3.5mW and pulsed mode with energy per measurement < 6mJ. Self powered operation using a solar cell is demonstrated together with wireless capability. Performance of two path length variants (20mm and 70mm) is described. The sensor shows invariant temperature output characteristic from -25 to 50 deg. C. Accuracy level is typically {+-}3% of reading.

  3. Red, Straight, no bends: primordial power spectrum reconstruction from CMB and large-scale structure

    Energy Technology Data Exchange (ETDEWEB)

    Ravenni, Andrea [Dipartimento di Fisica e Astronomia ' ' G. Galilei' ' , Università degli Studi di Padova, via Marzolo 8, I-35131, Padova (Italy); Verde, Licia; Cuesta, Antonio J., E-mail: andrea.ravenni@pd.infn.it, E-mail: liciaverde@icc.ub.edu, E-mail: ajcuesta@icc.ub.edu [Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, E08028 Barcelona (Spain)

    2016-08-01

    We present a minimally parametric, model independent reconstruction of the shape of the primordial power spectrum. Our smoothing spline technique is well-suited to search for smooth features such as deviations from scale invariance, and deviations from a power law such as running of the spectral index or small-scale power suppression. We use a comprehensive set of the state-of the art cosmological data: Planck observations of the temperature and polarisation anisotropies of the cosmic microwave background, WiggleZ and Sloan Digital Sky Survey Data Release 7 galaxy power spectra and the Canada-France-Hawaii Lensing Survey correlation function. This reconstruction strongly supports the evidence for a power law primordial power spectrum with a red tilt and disfavours deviations from a power law power spectrum including small-scale power suppression such as that induced by significantly massive neutrinos. This offers a powerful confirmation of the inflationary paradigm, justifying the adoption of the inflationary prior in cosmological analyses.

  4. Understanding A-type supergiants. I. Ultraviolet and visible spectral atlas of A-type supergiants

    CERN Document Server

    Verdugo, E; Gómez de Castro, A I

    1999-01-01

    This paper is the first of a series whose aim is to perform a systematic study of A-type supergiant atmospheres and winds. Here we present a spectral atlas of 41 A-supergiants observed by us in high and medium resolution in the visible and ultraviolet. The atlas consists of profiles of the H alpha , H beta , H gamma , H delta , H epsilon , Ca II (H and K), Na I (D1 and D2), Mg II/sub 4481/, Mg II uv1 and Fe II uv1, uv2, uv3, uv62, uv63, uv161 lines for 41 stars with spectral types ranging from B9 to A9 and luminosity classes Ia, Iab and Ib, and provides the basic data for a thoughtful study of these stars. The overall characteristics of the sample as well as the data reduction procedures are described. We also present some examples of spectral variability. Figures 1-3 are only available in electronic form at http://www.edpsciences.com. (27 refs).

  5. Hubble Space Telescope Imaging of the Mass-losing Supergiant VY Canis Majoris

    Science.gov (United States)

    Kastner, Joel H.; Weintraub, David A.

    1998-04-01

    The highly luminous M supergiant VY CMa is a massive star that appears to be in its final death throes, losing mass at high rate en route to exploding as a supernova. Subarcsecond-resolution optical images of VY CMa, obtained with the Faint Object Camera (FOC) aboard the Hubble Space Telescope, vividly demonstrate that mass loss from VY CMa is highly anisotropic. In the FOC images, the optical ``star'' VY CMa constitutes the bright, well-resolved core of an elongated reflection nebula. The imaged nebula is ~3" (~4500 AU) in extent and is clumpy and highly asymmetric. The images indicate that the bright core, which lies near one edge of the nebula, is pure scattered starlight. We conclude that at optical wavelengths VY CMa is obscured from view along our line of sight by its own dusty envelope. The presence of the extended reflection nebula then suggests that this envelope is highly flattened and/or that the star is surrounded by a massive circumstellar disk. Such axisymmetric circumstellar density structure should have profound effects on post-red supergiant mass loss from VY CMa and, ultimately, on the shaping of the remnant of the supernova that will terminate its post-main-sequence evolution.

  6. ISO observations of far-infrared rotational emission lines of water vapor toward the supergiant star VY Canis Majoris

    OpenAIRE

    Neufeld, David A.; Feuchtgruber, Helmut; Harwit, Martin; Melnick, Gary J.

    1999-01-01

    We report the detection of numerous far-infrared emission lines of water vapor toward the supergiant star VY Canis Majoris. A 29.5 - 45 micron grating scan of VY CMa, obtained using the Short Wavelength Spectrometer (SWS) of the Infrared Space Observatory (ISO) at a spectral resolving power of approximately 2000, reveals at least 41 spectral features due to water vapor that together radiate a total luminosity ~ 25 solar luminosities. In addition to pure rotational transitions within the groun...

  7. Cracking the Conundrum of F-supergiant Coronae

    Science.gov (United States)

    Ayres, Thomas R.

    2018-02-01

    Chandra X-ray and HST far-ultraviolet (FUV) observations of three early-F supergiants have shed new light on a previous puzzle involving a prominent member of the class: α Persei (HD 20902: F5 Ib). The warm supergiant is a moderately strong, hard coronal (T∼ {10}7 K) X-ray source, but has 10 times weaker “subcoronal” Si IV 1393 Å (T∼ 8× {10}4 K) emissions than early-G supergiants of similar high-energy properties. The α Per X-ray excess was speculatively ascribed to a close-in hyperactive G-dwarf companion, which could have escaped previous notice, lost in the glare of the bright star. However, a subsequent dedicated multi-wavelength imaging campaign failed to find any evidence for a resolved secondary. The origin of the α Per high-energy dichotomy then devolved to (1) an unresolved companion or (2) intrinsic coronal behavior. Exploring the second possibility, the present program has found that early-F supergiants do appear to belong to a distinct coronal class, characterized by elevated X-ray/FUV ratios, although sharing some similarities with Cepheid variables in their transitory X-ray “high states.” Remarkably, the early-F supergiants now are seen to align with the low-activity end of the X-ray/FUV sequence defined by late-type dwarfs, suggesting that the disjoint behavior relative to the G supergiants might be attributed to thinner outer atmospheres on the F types, as in dwarfs, but in this case perhaps caused by a weakened “ionization valve” effect due to overly warm photospheres.

  8. Utilization of red mud for the purification of waste waters from nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Luka, Mikelic; Visnja, Orescanin; Stipe, Lulic [Rudjer Boskovic Institute, Lab. for radioecology, Zagreb (Croatia)

    2006-07-01

    Sorption of the radionuclides and heavy metals from low level liquid radioactive waste on the coagulant produced from bauxite waste (red mud and waste base) was presented. Research was conducted on composite annual samples of waste water collected in the Waste Monitor Tank (W.M.T.) from Kro Nuclear Power Plant during each month. Activities of radionuclide in W.M.T. were measured before and after purification using high purity germanium detector. Also, elemental concentrations in W.M.T. before and after purification were measured by source excited energy dispersive X-ray fluorescence (E.D.X.R.F.). It has been showed that activated red mud is excellent purification agent for the removal of radionuclides present in low level liquid radioactive waste. Removal efficiency was 100% for the radionuclides {sup 58}Co and {sup 60}Co 100%, and over 60% for {sup 134}Cs and {sup 137}Cs. (authors)

  9. Utilization of red mud for the purification of waste waters from nuclear power plants

    International Nuclear Information System (INIS)

    Luka, Mikelic; Visnja, Orescanin; Stipe, Lulic

    2006-01-01

    Sorption of the radionuclides and heavy metals from low level liquid radioactive waste on the coagulant produced from bauxite waste (red mud and waste base) was presented. Research was conducted on composite annual samples of waste water collected in the Waste Monitor Tank (W.M.T.) from Kro Nuclear Power Plant during each month. Activities of radionuclide in W.M.T. were measured before and after purification using high purity germanium detector. Also, elemental concentrations in W.M.T. before and after purification were measured by source excited energy dispersive X-ray fluorescence (E.D.X.R.F.). It has been showed that activated red mud is excellent purification agent for the removal of radionuclides present in low level liquid radioactive waste. Removal efficiency was 100% for the radionuclides 58 Co and 60 Co 100%, and over 60% for 134 Cs and 137 Cs. (authors)

  10. There Are (super)Giants in the Sky: Searching for Misidentified Massive Stars in Algorithmically-Selected Quasar Catalogs

    Science.gov (United States)

    Dorn-Wallenstein, Trevor Z.; Levesque, Emily

    2017-11-01

    Thanks to incredible advances in instrumentation, surveys like the Sloan Digital Sky Survey have been able to find and catalog billions of objects, ranging from local M dwarfs to distant quasars. Machine learning algorithms have greatly aided in the effort to classify these objects; however, there are regimes where these algorithms fail, where interesting oddities may be found. We present here an X-ray bright quasar misidentified as a red supergiant/X-ray binary, and a subsequent search of the SDSS quasar catalog for X-ray bright stars misidentified as quasars.

  11. Asymmetric ejecta of cool supergiants and hypergiants in the massive cluster Westerlund 1

    Science.gov (United States)

    Andrews, H.; Fenech, D.; Prinja, R. K.; Clark, J. S.; Hindson, L.

    2018-06-01

    We report new 5.5 GHz radio observations of the massive star cluster Westerlund 1, taken by the Australia Telescope Compact Array, detecting nine of the ten yellow hypergiants (YHGs) and red supergiants (RSGs) within the cluster. Eight of nine sources are spatially resolved. The nebulae associated with the YHGs Wd1-4a, -12a, and -265 demonstrate a cometary morphology - the first time this phenomenon has been observed for such stars. This structure is also echoed in the ejecta of the RSGs Wd1-20 and -26; in each case the cometary tails are directed away from the cluster core. The nebular emission around the RSG Wd1-237 is less collimated than these systems but once again appears more prominent in the hemisphere facing the cluster. Considered as a whole, the nebular morphologies provide compelling evidence for sculpting via a physical agent associated with Westerlund 1, such as a cluster wind.

  12. Kinematic properties of supergiants in the Perseus spiral arm

    Energy Technology Data Exchange (ETDEWEB)

    Gerasimenko, T P [Ural' skij Gosudarstvennyj Univ., Sverdlovsk (USSR)

    1963-05-01

    Large-scale inhomogeneity of the velocity field in the Perseus spiral arm region is found on the basis of the analysis of spatial motions of supergiants. The inhomogeneity seems to be connected with both presence of large groups of young stars and systematic motions in the arm predicted by the density wave theory. Proper motions of 78 stars are presented.

  13. Spectroscopic Variability of Supergiant Star HD14134, B3Ia

    Indian Academy of Sciences (India)

    Y. M. Maharramov

    2017-06-19

    Jun 19, 2017 ... the hot supergiant HD14134 studied in the present paper has a mass-loss rate of ...... tific program for the priority fields of research of the. National .... emission-line stars in the Large Magellanic Cloud, Astron. Astrophys., 158 ...

  14. Supergiants and the Galactic metallicity gradient. II. Spectroscopic abundances for 64 distant F- to M-type supergiants

    International Nuclear Information System (INIS)

    Luck, R.E.; Bond, H.E.

    1989-01-01

    The metallicity gradient in the Galactic disk from in situ stars with visual magnitude ranging from 6 to 10 is analyzed. Atmospheric parameters and detailed chemical abundances for 64 Population I supergiants of spectral types F through M and luminosity classes Ia through II have been determined. The derived Fe/H ratios ranging from -0.5 to + 0.7 show a mean value of +0.13 with an estimated uncertainty of + or - 0.2. A subset of 25 supergiants fainter than 7th magnitude lying in the direction of the Galactic center shows a Fe/H mean of +0.18 + or - 0.04, while a similar sample of 15 faint supergiants lying in the direction of the Galactic anticenter shows a lower Fe/H mean of +0.07 + or - 0.06. For a sample of bright supergiants analyzed by Luck and Lambert (1985), the mean abundance pattern for all 64 stars showed the following: deficient C and O along with enhancement of N, indicating mixing of CNO-cycled material to the stellar surfaces; an apparent Sr enhancement attributed to departures from LTE; and an essentially solar pattern of other chemical elements. 50 refs

  15. Quantitative spectroscopy of blue supergiants in metal-poor dwarf galaxy NGC 3109

    International Nuclear Information System (INIS)

    Hosek, Matthew W. Jr.; Kudritzki, Rolf-Peter; Bresolin, Fabio; Urbaneja, Miguel A.; Przybilla, Norbert; Evans, Christopher J.; Pietrzyński, Grzegorz; Gieren, Wolfgang; Carraro, Giovanni

    2014-01-01

    We present a quantitative analysis of the low-resolution (∼4.5 Å) spectra of 12 late-B and early-A blue supergiants (BSGs) in the metal-poor dwarf galaxy NGC 3109. A modified method of analysis is presented which does not require use of the Balmer jump as an independent T eff indicator, as used in previous studies. We determine stellar effective temperatures, gravities, metallicities, reddening, and luminosities, and combine our sample with the early-B-type BSGs analyzed by Evans et al. to derive the distance to NGC 3109 using the flux-weighted gravity-luminosity relation (FGLR). Using primarily Fe-group elements, we find an average metallicity of [ Z-bar ] = –0.67 ± 0.13, and no evidence of a metallicity gradient in the galaxy. Our metallicities are higher than those found by Evans et al. based on the oxygen abundances of early-B supergiants ([ Z-bar ] = –0.93 ± 0.07), suggesting a low α/Fe ratio for the galaxy. We adjust the position of NGC 3109 on the BSG-determined galaxy mass-metallicity relation accordingly and compare it to metallicity studies of H II regions in star-forming galaxies. We derive an FGLR distance modulus of 25.55 ± 0.09 (1.27 Mpc) that compares well with Cepheid and tip of the red giant branch distances. The FGLR itself is consistent with those found in other galaxies, demonstrating the reliability of this method as a measure of extragalactic distances.

  16. The Type IIb Supernova 2013df and its Cool Supergiant Progenitor

    Science.gov (United States)

    VanDyk, Schuyler D.; Zeng, Weikang; Fox, Ori D.; Cenko, S. Bradley; Clubb, Kelsey I.; Filippenko, Alexei; Foley, Ryan J.; Miller, Adam A.; Smith, Nathan; Kelly, Patrick L.; hide

    2014-01-01

    We have obtained early-time photometry and spectroscopy of supernova (SN) 2013df in NGC 4414. The SN is clearly of Type II b, with notable similarities to SN 1993J. From its luminosity at secondary maximum light, it appears that less Ni-56 (is approximately less than 0.06M) was synthesized in the SN 2013df explosion than was the case for the SNe II b 1993J, 2008ax, and 2011dh. Based on a comparison of the light curves, the SN 2013df progenitor must have been more extended in radius prior to explosion than the progenitor of SN 1993J. The total extinction for SN 2013dfis estimated to be A(sub V) = 0.30 mag. The metallicity at the SN location is likely to be solar. We have conducted Hubble Space Telescope(HST) Target of Opportunity observations of the SN with the Wide Field Camera 3, and from a precise comparison of these new observations to archival HST observations of the host galaxy obtained 14 yr prior to explosion, we have identified the progenitor of SN 2013df to be a yellow supergiant, somewhat hotter than a red supergiant progenitor for a normal Type II-Plateau SN. From its observed spectral energy distribution, assuming that the light is dominated by one star, the progenitor had effective temperature T(sub eff) = 4250+/-100 K and a bolometric luminosity L(sub bol) =10(exp 4.94+/-0.06) Solar Luminosity. This leads to an effective radius Reff = 545+/-65 Solar Radius. The star likely had an initial mass in the range of 13-17Solar Mass; however, if it was a member of an interacting binary system, detailed modeling of the system is required to estimate this mass more accurately. The progenitor star of SN 2013df appears to have been relatively similar to the progenitor of SN 1993J.

  17. The type IIb supernova 2013df and its cool supergiant progenitor

    Energy Technology Data Exchange (ETDEWEB)

    Van Dyk, Schuyler D. [Spitzer Science Center/Caltech, Mail Code 220-6, Pasadena, CA 91125 (United States); Zheng, WeiKang; Fox, Ori D.; Clubb, Kelsey I.; Filippenko, Alexei V.; Kelly, Patrick L. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Cenko, S. Bradley [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Foley, Ryan J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Miller, Adam A. [Jet Propulsion Laboratory, MS 169-506, Pasadena, CA 91109 (United States); Smith, Nathan [Steward Observatory, University of Arizona, Tucson, AZ 85720 (United States); Lee, William H. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 70-264, Cd. Universitaria, México DF 04510 (Mexico); Ben-Ami, Sagi; Gal-Yam, Avishay, E-mail: vandyk@ipac.caltech.edu [Benoziyo Center for Astrophysics, The Weizmann Institute of Science, Rehovot 76100 (Israel)

    2014-02-01

    We have obtained early-time photometry and spectroscopy of supernova (SN) 2013df in NGC 4414. The SN is clearly of Type IIb, with notable similarities to SN 1993J. From its luminosity at secondary maximum light, it appears that less {sup 56}Ni (≲ 0.06 M {sub ☉}) was synthesized in the SN 2013df explosion than was the case for the SNe IIb 1993J, 2008ax, and 2011dh. Based on a comparison of the light curves, the SN 2013df progenitor must have been more extended in radius prior to explosion than the progenitor of SN 1993J. The total extinction for SN 2013df is estimated to be A{sub V} = 0.30 mag. The metallicity at the SN location is likely to be solar. We have conducted Hubble Space Telescope (HST) Target of Opportunity observations of the SN with the Wide Field Camera 3, and from a precise comparison of these new observations to archival HST observations of the host galaxy obtained 14 yr prior to explosion, we have identified the progenitor of SN 2013df to be a yellow supergiant, somewhat hotter than a red supergiant progenitor for a normal Type II-Plateau SN. From its observed spectral energy distribution, assuming that the light is dominated by one star, the progenitor had effective temperature T {sub eff} = 4250 ± 100 K and a bolometric luminosity L {sub bol} = 10{sup 4.94±0.06} L {sub ☉}. This leads to an effective radius R {sub eff} = 545 ± 65 R {sub ☉}. The star likely had an initial mass in the range of 13-17 M {sub ☉}; however, if it was a member of an interacting binary system, detailed modeling of the system is required to estimate this mass more accurately. The progenitor star of SN 2013df appears to have been relatively similar to the progenitor of SN 1993J.

  18. Quantitative spectroscopy of blue supergiants in metal-poor dwarf galaxy NGC 3109

    Energy Technology Data Exchange (ETDEWEB)

    Hosek, Matthew W. Jr.; Kudritzki, Rolf-Peter; Bresolin, Fabio [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Urbaneja, Miguel A.; Przybilla, Norbert [Institute for Astro and Particle Physics, A-6020 Innsbruck University (Austria); Evans, Christopher J. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh (United Kingdom); Pietrzyński, Grzegorz; Gieren, Wolfgang [Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Carraro, Giovanni, E-mail: mwhosek@ifa.hawaii.edu, E-mail: kud@ifa.hawaii.edu, E-mail: bresolin@ifa.hawaii.edu, E-mail: Miguel.Urbaneja-Perez@uibk.ac.at, E-mail: Norbert.Przybilla@uibk.ac.at, E-mail: chris.evans@stfc.ac.uk, E-mail: pietrzyn@astrouw.edu.pl, E-mail: wgieren@astro-udec.cl, E-mail: gcarraro@eso.org [European Southern Observatory, La Silla Paranal Observatory (Chile)

    2014-04-20

    We present a quantitative analysis of the low-resolution (∼4.5 Å) spectra of 12 late-B and early-A blue supergiants (BSGs) in the metal-poor dwarf galaxy NGC 3109. A modified method of analysis is presented which does not require use of the Balmer jump as an independent T {sub eff} indicator, as used in previous studies. We determine stellar effective temperatures, gravities, metallicities, reddening, and luminosities, and combine our sample with the early-B-type BSGs analyzed by Evans et al. to derive the distance to NGC 3109 using the flux-weighted gravity-luminosity relation (FGLR). Using primarily Fe-group elements, we find an average metallicity of [ Z-bar ] = –0.67 ± 0.13, and no evidence of a metallicity gradient in the galaxy. Our metallicities are higher than those found by Evans et al. based on the oxygen abundances of early-B supergiants ([ Z-bar ] = –0.93 ± 0.07), suggesting a low α/Fe ratio for the galaxy. We adjust the position of NGC 3109 on the BSG-determined galaxy mass-metallicity relation accordingly and compare it to metallicity studies of H II regions in star-forming galaxies. We derive an FGLR distance modulus of 25.55 ± 0.09 (1.27 Mpc) that compares well with Cepheid and tip of the red giant branch distances. The FGLR itself is consistent with those found in other galaxies, demonstrating the reliability of this method as a measure of extragalactic distances.

  19. Large Magellanic Cloud helium-rich peculiar blue supergiants and SN 1987A

    International Nuclear Information System (INIS)

    Tuchman, Y.; Wheeler, J.C.

    1990-01-01

    The theoretical distribution of massive stars in the H-R diagram is compared to the revised data of Fitzpatrick and Garmany for the LMC. Preferred models of about 20 M solar masses undergo a thermal contraction at T(eff) about 35,000 K at the end of core hydrogen burning but reestablish thermal equilibrium to the red of the main sequence at T(eff) about 20,000 K after ignition of a hydrogen-burning shell. They then evolve on a nuclear time scale to T(eff) about 6000 K where they lose thermal equilibrium and jump to the Hayashi track. The theoretical and observed distributions agree with two significant exceptions: the blue thermal contraction gap is overpopulated compared to the theory, and there is a ledge crossing the center of the H-R diagram. The hypothesis that some of the observed stars in the blue gap are secondaries that have accreted helium-rich matter from deep within the hydrogen envelope of a red supergiant primary is explored. Some preliminary observational justification is given. 27 refs

  20. Chemical complexity in the winds of the oxygen-rich supergiant star VY Canis Majoris

    Science.gov (United States)

    Ziurys, L. M.; Milam, S. N.; Apponi, A. J.; Woolf, N. J.

    2007-06-01

    The interstellar medium is enriched primarily by matter ejected from old, evolved stars. The outflows from these stars create spherical envelopes, which foster gas-phase chemistry. The chemical complexity in circumstellar shells was originally thought to be dominated by the elemental carbon to oxygen ratio. Observations have suggested that envelopes with more carbon than oxygen have a significantly greater abundance of molecules than their oxygen-rich analogues. Here we report observations of molecules in the oxygen-rich shell of the red supergiant star VY Canis Majoris (VY CMa). A variety of unexpected chemical compounds have been identified, including NaCl, PN, HNC and HCO+. From the spectral line profiles, the molecules can be distinguished as arising from three distinct kinematic regions: a spherical outflow, a tightly collimated, blue-shifted expansion, and a directed, red-shifted flow. Certain species (SiO, PN and NaCl) exclusively trace the spherical flow, whereas HNC and sulphur-bearing molecules (amongst others) are selectively created in the two expansions, perhaps arising from shock waves. CO, HCN, CS and HCO+ exist in all three components. Despite the oxygen-rich environment, HCN seems to be as abundant as CO. These results suggest that oxygen-rich shells may be as chemically diverse as their carbon counterparts.

  1. Power output and force-velocity relationship of red and white muscle fibres from the Pacific blue marlin (Makaira nigricans).

    Science.gov (United States)

    Johnston, I A; Salamonski, J

    1984-07-01

    Single white fibres and small bundles (two to three) of red fibres were isolated from the trunk muscle of Pacific Blue Marlin (50-121 kg body weight). Fibres were chemically skinned with 1% Brij. Maximum Ca2+-activated force production (Po) was 57 kN m-2 for red fibres and 176 kN m-2 for white fibres at 25 degrees C. The force-velocity (P-V) characteristics of these fibres were determined at 15 and 25 degrees C. Points below 0.6 Po on the P-V curve could be fitted to a linear form of Hill's equation. The degree of curvature of the P-V curve was similar at 15 and 25 degrees C (Hill's constant a/Po = 0.24 and 0.12 for red and white fibres respectively). Extrapolated maximum contraction velocities (Vmax) were 2.5 muscle lengths s-1 (Lo S-1) (red fibres) and 5.3 Lo S-1 (white fibres) at 25 degrees C. Q10(15-25 degrees C) values for Vmax were 1.4 and 1.3 for red and white fibres respectively. Maximum power output had a similar low temperature dependence and amounted to 13 W kg-1 for red and 57 W kg-1 for white muscle at 25 degrees C. The results are briefly discussed in relation to the locomotion and ecology of marlin.

  2. The blue supergiant MN18 and its bipolar circumstellar nebula

    Science.gov (United States)

    Gvaramadze, V. V.; Kniazev, A. Y.; Bestenlehner, J. M.; Bodensteiner, J.; Langer, N.; Greiner, J.; Grebel, E. K.; Berdnikov, L. N.; Beletsky, Y.

    2015-11-01

    We report the results of spectrophotometric observations of the massive star MN18 revealed via discovery of a bipolar nebula around it with the Spitzer Space Telescope. Using the optical spectrum obtained with the Southern African Large Telescope, we classify this star as B1 Ia. The evolved status of MN18 is supported by the detection of nitrogen overabundance in the nebula, which implies that it is composed of processed material ejected by the star. We analysed the spectrum of MN18 by using the code CMFGEN, obtaining a stellar effective temperature of ≈21 kK. The star is highly reddened, E(B - V) ≈ 2 mag. Adopting an absolute visual magnitude of MV = -6.8 ± 0.5 (typical of B1 supergiants), MN18 has a luminosity of log L/L⊙ ≈ 5.42 ± 0.30, a mass-loss rate of ≈(2.8-4.5) × 10- 7 M⊙ yr- 1, and resides at a distance of ≈5.6^{+1.5} _{-1.2} kpc. We discuss the origin of the nebula around MN18 and compare it with similar nebulae produced by other blue supergiants in the Galaxy (Sher 25, HD 168625, [SBW2007] 1) and the Large Magellanic Cloud (Sk-69°202). The nitrogen abundances in these nebulae imply that blue supergiants can produce them from the main-sequence stage up to the pre-supernova stage. We also present a K-band spectrum of the candidate luminous blue variable MN56 (encircled by a ring-like nebula) and report the discovery of an OB star at ≈17 arcsec from MN18. The possible membership of MN18 and the OB star of the star cluster Lynga 3 is discussed.

  3. Clumpy wind accretion in Supergiant X-ray Binaries

    Science.gov (United States)

    El Mellah, I.; Sundqvist, J. O.; Keppens, R.

    2017-12-01

    Supergiant X-ray binaries (\\sgx) contain a neutron star (NS) orbiting a Supergiant O/B star. The fraction of the dense and fast line-driven wind from the stellar companion which is accreted by the NS is responsible for most of the X-ray emission from those system. Classic \\sgx display photometric variability of their hard X-ray emission, typically from a few 10^{35} to a few 10^{37}erg\\cdots^{-1}. Inhomogeneities (\\aka clumps) in the wind from the star are expected to play a role in this time variability. We run 3D hydrodynamical (HD) finite volume simulations to follow the accretion of the inhomogeneous stellar wind by the NS over almost 3 orders of magnitude. To model the unperturbed wind far upstream the NS, we use recent simulations which managed to resolve its micro-structure. We observe the formation of a Bondi-Hoyle-Lyttleton (BHL) like bow shock around the accretor and follow the clumps as they cross it, down to the NS magnetosphere. Compared to previous estimations discarding the HD effects, we measure lower time variability due to both the damping effect of the shock and the necessity to evacuate angular momentum to enable accretion. We also compute the associated time-variable column density and compare it to recent observations in Vela X-1.

  4. The Swift Supergiant Fast X-ray Transient Project

    Science.gov (United States)

    Romano, P.; Barthelmy, S.; Bozzo, E.; Burrows, D.; Ducci, L.; Esposito, P.; Evans, P.; Kennea, J.; Krimm, H.; Vercellone, S.

    2017-10-01

    We present the Swift Supergiant Fast X-ray Transients project, a systematic study of SFXTs and classical supergiant X-ray binaries (SGXBs) through efficient long-term monitoring of 17 sources including SFXTs and classical SGXBs across more than 4 orders of magnitude in X-ray luminosity on timescales from hundred seconds to years. We derived dynamic ranges, duty cycles, and luminosity distributions to highlight systematic differences that help discriminate between different theoretical models proposed to explain the differences between the wind accretion processes in SFXTs and classical SGXBs. Our follow-ups of the SFXT outbursts provide a steady advancement in the comprehension of the mechanisms triggering the high X-ray level emission of these sources. In particular, the observations of the outburst of the SFXT prototype IGR J17544-2619, when the source reached a peak X-ray luminosity of 3×10^{38} erg s^{-1}, challenged for the first time the maximum theoretical luminosity achievable by a wind-fed neutron star high mass X-ray binary. We propose that this giant outburst was due to the formation of a transient accretion disc around the compact object. We also created a catalogue of over 1000 BAT flares which we use to predict the observability and perspectives with future missions.

  5. Towards a Unified View of Inhomogeneous Stellar Winds in Isolated Supergiant Stars and Supergiant High Mass X-Ray Binaries

    Science.gov (United States)

    Martínez-Núñez, Silvia; Kretschmar, Peter; Bozzo, Enrico; Oskinova, Lidia M.; Puls, Joachim; Sidoli, Lara; Sundqvist, Jon Olof; Blay, Pere; Falanga, Maurizio; Fürst, Felix; Gímenez-García, Angel; Kreykenbohm, Ingo; Kühnel, Matthias; Sander, Andreas; Torrejón, José Miguel; Wilms, Jörn

    2017-10-01

    Massive stars, at least ˜10 times more massive than the Sun, have two key properties that make them the main drivers of evolution of star clusters, galaxies, and the Universe as a whole. On the one hand, the outer layers of massive stars are so hot that they produce most of the ionizing ultraviolet radiation of galaxies; in fact, the first massive stars helped to re-ionize the Universe after its Dark Ages. Another important property of massive stars are the strong stellar winds and outflows they produce. This mass loss, and finally the explosion of a massive star as a supernova or a gamma-ray burst, provide a significant input of mechanical and radiative energy into the interstellar space. These two properties together make massive stars one of the most important cosmic engines: they trigger the star formation and enrich the interstellar medium with heavy elements, that ultimately leads to formation of Earth-like rocky planets and the development of complex life. The study of massive star winds is thus a truly multidisciplinary field and has a wide impact on different areas of astronomy. In recent years observational and theoretical evidences have been growing that these winds are not smooth and homogeneous as previously assumed, but rather populated by dense "clumps". The presence of these structures dramatically affects the mass loss rates derived from the study of stellar winds. Clump properties in isolated stars are nowadays inferred mostly through indirect methods (i.e., spectroscopic observations of line profiles in various wavelength regimes, and their analysis based on tailored, inhomogeneous wind models). The limited characterization of the clump physical properties (mass, size) obtained so far have led to large uncertainties in the mass loss rates from massive stars. Such uncertainties limit our understanding of the role of massive star winds in galactic and cosmic evolution. Supergiant high mass X-ray binaries (SgXBs) are among the brightest X

  6. Chemical composition of late-type supergiants. IV. Homogeneous abundances and galactic metallicity trends

    International Nuclear Information System (INIS)

    Luck, R.E.

    1982-01-01

    In a recent series of papers by Luck and by Luck and Bond on the chemical composition of G and K lb supergiants, [Fe/H] ratios were determined from high-dispersion spectroscopic data for 54 stars. The main results were: (1) that supergiants in the solar neighborhood have about twice the iron content of the Sun ( = +0.3); and (2) that supergiants between 7.7 and 10.2 kpc from the galactic center show a steep radial metallicity gradient, d[Fe/H]/dR = -0.24 kpc -1

  7. A modern study of HD 166734: a massive supergiant system

    Science.gov (United States)

    Mahy, L.; Damerdji, Y.; Gosset, E.; Nitschelm, C.; Eenens, P.; Sana, H.; Klotz, A.

    2017-11-01

    Aims: HD 166734 is an eccentric eclipsing binary system composed of two supergiant O-type stars, orbiting with a 34.5-day period. In this rare configuration for such stars, the two objects mainly evolve independently, following single-star evolution so far. This system provides a chance to study the individual parameters of two supergiant massive stars and to derive their real masses. Methods: An intensive monitoring was dedicated to HD 166734. We analyzed mid- and high-resolution optical spectra to constrain the orbital parameters of this system. We also studied its light curve for the first time, obtained in the VRI filters. Finally, we disentangled the spectra of the two stars and modeled them with the CMFGEN atmosphere code in order to determine the individual physical parameters. Results: HD 166734 is a O7.5If+O9I(f) binary. We confirm its orbital period but we revise the other orbital parameters. In comparison to what we found in the literature, the system is more eccentric and, now, the hottest and the most luminous component is also the most massive one. The light curve exhibits only one eclipse and its analysis indicates an inclination of 63.0° ± 2.7°. The photometric analysis provides us with a good estimation of the luminosities of the stars, and therefore their exact positions in the Hertzsprung-Russell diagram. The evolutionary and the spectroscopic masses show good agreement with the dynamical masses of 39.5 M⊙ for the primary and 33.5 M⊙ for the secondary, within the uncertainties. The two components are both enriched in helium and in nitrogen and depleted in carbon. In addition, the primary also shows a depletion in oxygen. Their surface abundances are however not different from those derived from single supergiant stars, yielding, for both components, an evolution similar to that of single stars. Based on observations collected at the European Southern Observatory (La Silla, Chile) with FEROS and TAROT and on data collected at the San Pedro

  8. Magnetic field evidence for the supergiant ν Cep (HD 207260)

    International Nuclear Information System (INIS)

    Scholz, G.; Gerth, E.

    1981-01-01

    On the basis of 55 Zeeman spectrograms the effective magnetic fields and the radial velocities of the supergiant ν Cep (HD 207260) were determined. For the effective magnetic field a slow variation occurring on a time-scale of years was found. The spectrograms taken at the first epoch show only moderate effective magnetic field strengths of a few hundred Gauss but in 1978 values of + 2000 G were detected. The measured radial velocities show a long-term variability similar to that of the magnetic field as well as more rapid changes of approximately equal to 39.9 day. Not only the Balmer absorption lines Hβ, Hγ, and Hdelta but also the various elements and ions have different radial velocities. (author)

  9. Expanding chromospheres of late G and K supergiants

    Energy Technology Data Exchange (ETDEWEB)

    Mallik, S V

    1986-09-15

    The radiative transfer problem in non-LTE moving atmospheres has been explicitly solved for H..cap alpha.. line profiles. These computations have been done for a schematic model of the line-forming region over a wide range of optical depths and velocity gradients in order to cover the observed characteristics in 23 G and K supergiants. The best theoretical fits yield optical depths in the range 10-500 and velocity fields in the range 0.5-3 Doppler widths. The computed mass-flow rates lie in the range 10/sup -5/-10/sup -7/ Solar Mass yr/sup -1/; the higher the extent of the line-forming region, the lower the mass-loss rates. The effect of the extent on the H..cap alpha.. emission components has also been investigated in some detail.

  10. Additional radial velocities of supergiants in the Small Magellanic Cloud

    International Nuclear Information System (INIS)

    Thackeray, A.D.

    1978-01-01

    Additional radial velocities of 28 SMC supergiants determined in the years 1959-69 at the Radcliffe Observatory are presented. These and other measures from ESO and elsewhere are intercompared. The mean Radcliffe velocities have an internal standard error of +- 4.7 km/s and a systematic error exceeding 4 km/s is regarded as unlikely. Eight stars in the SMC core have a corrected velocity dispersion of only 6.9 km/s, similar to Feast's values for H II regions in the core. But the core H II regions have a velocity differential of -20 km/s relative to these stars. The velocity dispersion for stars in other parts of the Cloud is of the order 15 km/s as previously found. Two possibly variable-velocity stars are discussed, without reaching a satisfactory conclusion. (author)

  11. The effect of high power ultrasound on phenolic composition, chromatic characteristics, and aroma compounds of red wines

    Directory of Open Access Journals (Sweden)

    Natka Ćurko

    2017-01-01

    Full Text Available High power ultrasound (HPU is a novel, non-thermal technology the application of which has been primarily evaluated in managing food quality. The application of high power ultrasound in wine technology is therefore directed at modulating microbial activity during fermentation, extraction of phenolic and aroma compounds from grapes to must, as well as at accelerating aging reactions in wine. The main aim of this article was to evaluate the effect of different HPU process parameters on sustaining the phenolic and aroma composition of red wine and its colour characteristics. Three different red wines, including Cabernet Sauvignon, Merlot, and Plavac mali, were treated with high power ultrasound (20kHz, considering the variations in ultrasound probe diameter size (12.7 and 19 mm, amplitude level (20, 30, and 40 %, and processing time (2, 4, and 6 minutes. Total polyphenol content, total anthocyanin concentration, and chromatic characteristics were analyzed by spectrophotometry, free anthocyanins were analysed by high performance liquid chromatography, and wine aroma compounds were analyzed by gas chromatography combined with solid-phase microextraction. The obtained results show that ultrasonic irradiation induces chemical changes in phenolic composition, chromatic characteristics, and aroma compounds concentration, and accelerates chemical reactions responsible for wine aging. The intensity of the mentioned chemical changes depends on the selected processing parameters and on the treated variety. Among three different parameters, the selection of the probe diameter was showed to be most significant factor influencing chemical composition, followed by the amplitude level and processing time. The smaller diameter probe size (12.7 mm, lowest amplitude (20%, and a shorter processing time (2 minutes showed a more favourable and lighter effect on the chemical composition of the treated red wines.

  12. Resolving the clumpy circumstellar environment of the B[e] supergiant LHA 120-S 35

    Science.gov (United States)

    Torres, A. F.; Cidale, L. S.; Kraus, M.; Arias, M. L.; Barbá, R. H.; Maravelias, G.; Borges Fernandes, M.

    2018-05-01

    . The outermost regions show a complex structure, outlined by fragmented clumps or partial-ring features of Ca II and O I. Additionally, we observe variations in the profiles of the only visible absorption features, the He I lines. Conclusions: We suggest that LHA 120-S 35 has passed through the red-supergiant (RSG) phase and evolves back bluewards in the Hertzsprung-Russell diagram. In this scenario, the formation of the complex circumstellar structure could be the result of the wind-wind interactions of the post-RSG wind with the previously ejected material from the RSG. The accumulation of material in the circumstellar environment could be attributed to enhanced mass-loss, probably triggered by stellar pulsations. However, the presence of a binary companion cannot be excluded. Finally, we find that LHA 120-S 35 is the third B[e] supergiant belonging to a young stellar cluster. Based on data acquired using (1) the du Pont Telescope at Las Campanas Observatory, Chile, under the programme CNTAC 2008-02 (PI: Barbá), (2) the MPG 2.2-m Telescope at La Silla Observatory, Chile, under the programme ID.: 094.A-9029(D) and under the agreement MPI-Observatório Nacional/MCTIC, Prog. ID.: 096.A-9030(A), (3) the J. Sahade 2.15-m Telescope at Complejo Astronómico El Leoncito, operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba and San Juan, (4) the 8.1-m Telescope at Gemini South 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 Ciěncia, Tecnologia e Inovacão (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), under the programme

  13. THE TYPE IIb SUPERNOVA 2011dh FROM A SUPERGIANT PROGENITOR

    International Nuclear Information System (INIS)

    Bersten, Melina C.; Nomoto, Ken'ichi; Folatelli, Gastón; Maeda, Keiichi; Benvenuto, Omar G.; Ergon, Mattias; Sollerman, Jesper; Benetti, Stefano; Ochner, Paolo; Tomasella, Lina; Botticella, Maria Teresa; Fraser, Morgan; Kotak, Rubina

    2012-01-01

    A set of hydrodynamical models based on stellar evolutionary progenitors is used to study the nature of SN 2011dh. Our modeling suggests that a large progenitor star—with R ∼ 200 R ☉ —is needed to reproduce the early light curve (LC) of SN 2011dh. This is consistent with the suggestion that the yellow super-giant star detected at the location of the supernova (SN) in deep pre-explosion images is the progenitor star. From the main peak of the bolometric LC and expansion velocities, we constrain the mass of the ejecta to be ≈2 M ☉ , the explosion energy to be E = (6-10) × 10 50 erg, and the 56 Ni mass to be approximately 0.06 M ☉ . The progenitor star was composed of a helium core of 3-4 M ☉ and a thin hydrogen-rich envelope of ≈0.1M ☉ with a main-sequence mass estimated to be in the range of 12-15 M ☉ . Our models rule out progenitors with helium-core masses larger than 8 M ☉ , which correspond to M ZAMS ∼> 25M ☉ . This suggests that a single star evolutionary scenario for SN 2011dh is unlikely.

  14. Ultraviolet extinction in M-supergiant circumstellar envelopes

    International Nuclear Information System (INIS)

    Buss, R.H. Jr.; Snow, T.P. Jr.

    1986-01-01

    Using International Ultraviolet (IUS) archival low-dispersion spectra, ultraviolet spectral extinctions were derived for the circumstellar envelopes of two M supergiants: HD 60414 and HD 213310. The observed stellar systems belong to a class of widely-separated spectroscopic binaries that are called VV Cephei stars. The total extinction was calculated by dividing the reddened fluxes with unreddened comparison fluxes of similar stars (g B2.5 for HD 213310 and a normalized s+B3 for HD 60414) from the reference atlas. After substracting the interstellar extinctions, which were estimated from the E(B-V) reddening of nearby stars, the resultant circumstellar extinctions were normalized at about 3.5 inverse microns. Not only is the 2175 A extinction bump absent in the circumstellar extinctions, but the far-ultraviolet extinction rise is also absent. The rather flat, ultraviolet extinction curves were interpreted as signatures of a population of noncarbonaceous, oxygen-rich grains with diameters larger than the longest observed wavelength

  15. The RED (reduce everyone's dose) initiative at Hinkley Point Power Station

    International Nuclear Information System (INIS)

    Weston, J.

    1995-01-01

    This paper does not offer a universal solution to reducing doses nor does it claim to introduce radically new ideas. It is a summarised account of the successes achieved in reducing the collective dose at a 30 year old power station. The key areas identified are the rewards of teamwork, the need to challenge established practices and the benefit of a dosimetry database. (author)

  16. Seven years with the Swift Supergiant Fast X-ray Transients project

    Science.gov (United States)

    Romano, P.

    2015-09-01

    Supergiant Fast X-ray Transients (SFXTs) are HMXBs with OB supergiant companions. I review the results of the Swift SFXT project, which since 2007 has been exploiting Swift's capabilities in a systematic study of SFXTs and supergiant X-ray binaries (SGXBs) by combining follow-ups of outbursts, when detailed broad-band spectroscopy is possible, with long-term monitoring campaigns, when the out-of-outburst fainter states can be observed. This strategy has led us to measure their duty cycles as a function of luminosity, to extract their differential luminosity distributions in the soft X-ray domain, and to compare, with unprecedented detail, the X-ray variability in these different classes of sources. I also discuss the ;seventh year crisis;, the challenges that the recent Swift observations are making to the prevailing models attempting to explain the SFXT behavior.

  17. The 13Carbon footprint of B[e] supergiants

    Science.gov (United States)

    Liermann, A.; Kraus, M.; Schnurr, O.; Fernandes, M. Borges

    2010-10-01

    We report on the first detection of 13C enhancement in two B[e] supergiants (B[e]SGs) in the Large Magellanic Cloud. Stellar evolution models predict the surface abundance in 13C to strongly increase during main-sequence and post-main-sequence evolution of massive stars. However, direct identification of chemically processed material on the surface of B[e]SGs is hampered by their dense, disc-forming winds, hiding the stars. Recent theoretical computations predict the detectability of enhanced 13C via the molecular emission in 13CO arising in the circumstellar discs of B[e]SGs. To test this potential method and to unambiguously identify a post-main-sequence B[e] SG by its 13CO emission, we have obtained high-quality K-band spectra of two known B[e] SGs in the Large Magellanic Cloud, using the Very Large Telescope's Spectrograph for INtegral Field Observation in the Near-Infrared (VLT/SINFONI). Both stars clearly show the 13CO band emission, whose strength implies a strong enhancement of 13C, in agreement with theoretical predictions. This first ever direct confirmation of the evolved nature of B[e]SGs thus paves the way to the first identification of a Galactic B[e]SG. Based on observations collected with the ESO VLT Paranal Observatory under programme 384.D-1078(A). E-mail: liermann@mpifr-bonn.mpg.de (AL); kraus@sunstel.asu.cas.cz (MK); oschnurr@aip.de (OS); borges@on.br (MBF)

  18. A Runaway Yellow Supergiant Star in the Small Magellanic Cloud

    Science.gov (United States)

    Neugent, Kathryn F.; Massey, Philip; Morrell, Nidia I.; Skiff, Brian; Georgy, Cyril

    2018-05-01

    We recently discovered a yellow supergiant (YSG) in the Small Magellanic Cloud (SMC) with a heliocentric radial velocity of ∼300 km s‑1, which is much larger than expected for a star at its location in the SMC. This is the first runaway YSG ever discovered and only the second evolved runaway star discovered in a galaxy other than the Milky Way. We classify the star as G5-8 I and use de-reddened broad-band colors with model atmospheres to determine an effective temperature of 4700 ± 250 K, consistent with what is expected from its spectral type. The star’s luminosity is then log L/L ⊙ ∼ 4.2 ± 0.1, consistent with it being a ∼30 Myr 9 M ⊙ star according to the Geneva evolution models. The star is currently located in the outer portion of the SMC’s body, but if the star’s transverse peculiar velocity is similar to its peculiar radial velocity, in 10 Myr the star would have moved 1.°6 across the disk of the SMC and could easily have been born in one of the SMC’s star-forming regions. Based on its large radial velocity, we suggest it originated in a binary system where the primary exploded as a supernovae, thus flinging the runaway star out into space. Such stars may provide an important mechanism for the dispersal of heavier elements in galaxies given the large percentage of massive stars that are runaways. In the future, we hope to look into additional evolved runaway stars that were discovered as part of our other past surveys. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  19. Luminosities and mass-loss rates of Local Group AGB stars and red supergiants

    Science.gov (United States)

    Groenewegen, M. A. T.; Sloan, G. C.

    2018-01-01

    Context. Mass loss is one of the fundamental properties of asymptotic giant branch (AGB) stars, and through the enrichment of the interstellar medium, AGB stars are key players in the life cycle of dust and gas in the universe. However, a quantitative understanding of the mass-loss process is still largely lacking. Aims: We aim to investigate mass loss and luminosity in a large sample of evolved stars in several Local Group galaxies with a variety of metalliticies and star-formation histories: the Small and Large Magellanic Cloud, and the Fornax, Carina, and Sculptor dwarf spheroidal galaxies (dSphs). Methods: Dust radiative transfer models are presented for 225 carbon stars and 171 oxygen-rich evolved stars in several Local Group galaxies for which spectra from the Infrared Spectrograph on Spitzer are available. The spectra are complemented with available optical and infrared photometry to construct spectral energy distributions. A minimization procedure was used to determine luminosity and mass-loss rate (MLR). Pulsation periods were derived for a large fraction of the sample based on a re-analysis of existing data. Results: New deep K-band photometry from the VMC survey and multi-epoch data from IRAC (at 4.5 μm) and AllWISE and NEOWISE have allowed us to derive pulsation periods longer than 1000 days for some of the most heavily obscured and reddened objects. We derive (dust) MLRs and luminosities for the entire sample. The estimated MLRs can differ significantly from estimates for the same objects in the literature due to differences in adopted optical constants (up to factors of several) and details in the radiative transfer modelling. Updated parameters for the super-AGB candidate MSX SMC 055 (IRAS 00483-7347) are presented. Its current mass is estimated to be 8.5 ± 1.6 M⊙, suggesting an initial mass well above 8 M⊙ in agreement with estimates based on its large Rubidium abundance. Using synthetic photometry, we present and discuss colour-colour and colour-magnitude diagrams which can be expected from the James Webb Space Telescope. Tables A.1, A.2, B.1, B.2, and C.1 are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A114

  20. The Asymmetric Nebula Surrounding the Extreme Red Supergiant VY Canis Majoris

    Science.gov (United States)

    Smith, Nathan; Humphreys, Roberta M.; Davidson, Kris; Gehrz, Robert D.; Schuster, M. T.; Krautter, Joachim

    2001-02-01

    We present HST/WFPC2 images plus ground-based infrared images and photometry of the very luminous OH/IR star VY Canis Majoris. Our WFPC2 data show a complex distribution of knots and filamentary arcs in the asymmetric reflection nebula around the obscured central star. The reflection arcs may result from multiple, asymmetric ejection episodes due to localized events on VY CMa's surface. Such events probably involve magnetic fields and convection, by analogy with solar activity. Surface photometry indicates that the star may have experienced enhanced mass loss over the past 1000 yr. We also demonstrate that the apparent asymmetry of the nebula results from a combination of high extinction and backscattering by dust grains. Thermal-infrared images reveal a more symmetric distribution, elongated along a nearly east-west direction. VY CMa probably has a flattened disklike distribution of dust with a northeast-southwest polar axis and may be experiencing activity analogous to solar prominences. The presence of an axis of symmetry raises interesting questions for a star the size of Saturn's orbit. Magnetic fields and surface activity may play an important role in VY CMa's mass-loss history. Based on observations made with the NASA/ESA Hubble Space Telescope, 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.

  1. VizieR Online Data Catalog: Red supergiant population in Perseus arm (Dorda+, 2018)

    Science.gov (United States)

    Dorda, R.; Negueruela, I.; Gonzalez-Fernandez, C.

    2018-03-01

    The targets were observed during two different campaigns. The first one was done in 2011, on the nights of October 16-18. The second campaign was carried out in 2012, from September 3rd to 7th. We used the Intermediate Dispersion Spectrograph, mounted on the 2.5 m Isaac Newton Telescope (INT) in La Palma (Spain). In total, we observed 637 unique targets, 102 in 2011 and 535 in 2012, without any overlap between epochs. As discussed above, 43 of them are CSGs with well-determined SpTs (all but one observed in the 2012 run) that were included in the calibration sample of Paper III (see appendix B in that work). These objects are not considered part of the Perseus sample studied here. This leaves 594 targets in our sample, which are detailed in perseus.dat file. (1 data file).

  2. Red Cloud’s War: A Failure to Effectively Coordinate the Instruments of National Power

    Science.gov (United States)

    2016-06-10

    to the campaign and the political climate in the United States in 1868, and was facilitated by the progress of the transcontinental railroad. The...categorizing the instruments of national power that a state or government has at its disposal for the formulation, influence , and execution of its...and economic measures to influence and coerce both state and non-state actors is not new. Thucydides wrote about diplomacy, economics, and military

  3. Evolution of a blue supergiant with a neutron star companion immersed in its envelope

    International Nuclear Information System (INIS)

    Delgado, A.J.

    1980-01-01

    The evolution of a binary system consisting of 1 Msub(sun) neutron star and a 25 Msub(sun) blue supergiant through a phase of common envelope is investigated. We include the effects of an additional energy source on the supergiant's envelope, due to the presence of the neutron star, and variable mass loss from the system, taken as proportional to the total luminosity. The results indicate that, independently of the initial period, the system loses its whole envelope as a consequence of the common envelope phase, the final product of this being a detached system, consisting of a neutron star and a helium star. (orig.)

  4. Effect of low-power red light laser irradiation on the viability of human skin fibroblast

    Energy Technology Data Exchange (ETDEWEB)

    Bednarska, K.; Rozga, B.; Leyko, W.; Bryszewska, M. [Institute of Biophysics, University of Lodz (Poland); Kolodziejczyk, K.; Szosland, D. [Diabetological Clinic, Medical Academy of Lodz (Poland)

    1998-10-01

    Human skin fibroblast monolayers (S-126 cell line) were exposed to laser radiation (wavelength 670 nm, power density 40 mW/cm{sup 2}). The energy densities were 2 J/cm{sup 2} and 12 J/cm{sup 2}, respectively, and the irradiation was carried out at a temperature of 22 C. For fibroblast viability evaluation, the colorimetric assay (conversion of thiazolyl blue to formazan) was used. The experiments were carried out at 37 C, in the presence of 5% CO{sub 2}, and at different time periods of incubation after irradiation (2, 4, 8 h and 1, 2, 3, 4, 5 days). The results indicated that there was a certain stimulating effect on the long-term proliferation of skin fibroblasts and that the stimulation proceeded in two stages, the first one 2 h and the second one 3 days post-irradiation. (orig.) With 4 figs., 2 tabs., 13 refs.

  5. Inhomogeneous molecular ring around the B[e] supergiant LHA 120-S 73

    Czech Academy of Sciences Publication Activity Database

    Kraus, Michaela; Cidale, L.S.; Arias, M.L.; Maravelias, Grigorios; Nickeler, Dieter Horst; Torres, A.F.; Borges Fernandes, M.; Aret, A.; Curé, M.; Vallverdú, R.; Barbá, R.H.

    2016-01-01

    Roč. 593, September (2016), s. 1-14 ISSN 0004-6361 R&D Projects: GA ČR(CZ) GA14-21373S; GA MŠk(CZ) 7AMB14AR017 Institutional support: RVO:67985815 Keywords : circumstellar matter * early-type stars * supergiants Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  6. On the hydrogen neutral outflowing disks of B[e] supergiants

    Czech Academy of Sciences Publication Activity Database

    Kraus, Michaela; Borges Fernandes, M.; de Araújo, F. X.

    2007-01-01

    Roč. 463, č. 2 (2007), s. 627-634 ISSN 0004-6361 R&D Projects: GA ČR GA205/04/1267 Institutional research plan: CEZ:AV0Z10030501 Keywords : supergiants * winds * outflows Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.259, year: 2007

  7. ARE ULTRA-LONG GAMMA-RAY BURSTS CAUSED BY BLUE SUPERGIANT COLLAPSARS, NEWBORN MAGNETARS, OR WHITE DWARF TIDAL DISRUPTION EVENTS?

    Energy Technology Data Exchange (ETDEWEB)

    Ioka, Kunihito [Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Hotokezaka, Kenta; Piran, Tsvi, E-mail: kunihito.ioka@yukawa.kyoto-u.ac.jp [Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel)

    2016-12-10

    Ultra-long gamma-ray bursts (ulGRBs) are a new population of GRBs with extreme durations of ∼10{sup 4} s. Leading candidates for their origin are blue supergiant collapsars, magnetars, and white dwarf tidal disruption events (WD-TDEs) caused by massive black holes (BHs). Recent observations of supernova-like (SN-like) bumps associated with ulGRBs challenged both the WD-TDE and the blue supergiant models because of the detection of SNe and the absence of hydrogen lines, respectively. We propose that WD-TDEs can accommodate the observed SN-like bumps if the fallback WD matter releases energy into the unbound WD ejecta. The observed ejecta energy, luminosity, and velocity are explained by the gravitational energy, Eddington luminosity, and escape velocity of the formed accretion disk, respectively. We also show that the observed X-rays can ionize the ejecta, eliminating lines. The SN-like light curves (SN 2011kl) for the ulGRB 111209A are consistent with all three models, although a magnetar model is unnatural because the spin-down time required to power the SN-like bump is a hundred times longer than the GRB. Our results imply that TDEs are a possible energy source for SN-like events in general and for ulGRBs in particular.

  8. Bare face red-brown bricks manufactured with fly ash from the Narcea (Asturias Coal Power Plan

    Directory of Open Access Journals (Sweden)

    Ayesta, G.

    1999-12-01

    Full Text Available Fly ash, from the Coal Power Plant of Narcea (Asturias, has been used to determine its possible use as a raw material in the bare face red-brown brick manufacture. The correct mould of a ceramic material demands a paste with an adequate plasticity. So, the optimum compositions of humidity, lubricant (talc and binder (white dextrin have been investigated. The samples were made by compressing paste into a mould using varying values of pressure and boiling temperature once the cooling speed had been established. Finally, the cooked pieces were submitted to trials demanded by the Basic Construction Norm, to see if they met the required specifications concerning Water Absorption, Suction, Contraction, Resistance to Freezing, Efflorescence and Compressive Strength.

    Se caracterizan las cenizas volantes de la Central Térmica del Narcea (Asturias para determinar su utilización como materia prima en la obtención de ladrillos cara vista. El moldeo correcto de una pieza cerámica exige trabajar una pasta con una adecuada plasticidad, para ello se investiga cuál ha de ser la composición óptima de la misma, en cuanto a: humedad, cantidad de lubricante (talco y de ligante (dextrina blanca. El conformado de las piezas o ladrillos se realiza por prensado, utilizando distintos valores de presión, así como la temperatura de cocción, una vez establecida la velocidad de enfriamiento. Finalmente, las piezas cocidas se someten a los ensayos exigidos por la Norma Básica de Edificación, para ver si cumplen las especificaciones requeridas en cuanto a: Absorción de agua. Succión, Contracción, Heladicidad, Eflorescencia y Resistencia a la compresión.

  9. Training-induced annual changes in red blood cell profile in highly-trained endurance and speed-power athletes.

    Science.gov (United States)

    Ciekot-Sołtysiak, Monika; Kusy, Krzysztof; Podgórski, Tomasz; Zieliński, Jacek

    2017-10-24

    An extensive body of literature exists on the effects of training on haematological parameters, but the previous studies have not reported how hematological parameters respond to changes in training loads within consecutive phases of the training cycle in highly-trained athletes in extremely different sport disciplines. The aim of this study was to identify changes in red blood cell (RBC) profile in response to training loads in consecutive phases of the annual training cycle in highly-trained sprinters (8 men, aged 24 ± 3 years) and triathletes (6 men, aged 24 ± 4 years) who competed at the national and international level. Maximal oxygen uptake (VO2max), RBC, haemoglobin (Hb), haematocrit (Ht), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) and RBC distribution width (RDW) were determined in four characteristic training phases (transition, general subphase of the preparation phase, specific subphase of the preparation phase and competition phase). Our main findings are that (1) Hb, MCH and MCHC in triathletes and MCV in both triathletes and sprinters changed significantly over the annual training cycle, (2) triathletes had significantly higher values than sprinters only in case of MCH and MCHC after the transition and general preparation phases but not after the competition phase when MCH and MCHC were higher in sprinters and (3) in triathletes, Hb, MCH and MCHC substantially decreased after the competition phase, which was not observed in sprinters. The athletes maintained normal ranges of all haematological parameters in four characteristic training phases. Although highly-trained sprinters and triathletes do not significantly differ in their levels of most haematological parameters, these groups are characterized by different patterns of changes during the annual training cycle. Our results suggest that when interpreting the values of haematological parameters in speed-power and endurance

  10. Low-frequency photospheric and wind variability in the early-B supergiant HD2905

    DEFF Research Database (Denmark)

    Simon-Diaz, S.; Aerts, C.; Urbaneja, M. A.

    2018-01-01

    to the lack of adequate observations for a proper characterization of the complex spectroscopic and photometric variability occurring in these stars. Aims. Our goal is to detect, analyze, and interpret variability in the early-B-type supergiant HD2905 (kappa Cas, B1 Ia) using long-term, ground-based, high...... snapshot and time-dependent information about the stellar parameters and abundances by means of the FASTWIND stellar atmosphere code. Results. HD2905 is a spectroscopic variable with peak-to-peak amplitudes in the zero and first moments of the photospheric lines of up to 15% and 30 km s(-1), respectively....... Conclusions. Combined long-term uninterrupted space photometry with high-precision spectroscopy is the best strategy to unravel the complex low-frequency photospheric and wind variability of B supergiants. Three-dimensional (3D) simulations of waves and of convective motions in the sub-surface layers can shed...

  11. Semi-analytical Formulas for the Fundamental Parameters of Galactic Early B Supergiants

    Directory of Open Access Journals (Sweden)

    Zaninetti, L.

    2009-12-01

    Full Text Available The publication of new tables of calibration of some fundamental parameters of Galactic B0-B5 supergiants in the two classes $I_mathrm{a}$ and $I_mathrm{b} $ allows to particularize the eight parameters conjecture that model five fundamental parameters. The numerical expressions for visual magnitude, radius, mass, luminosity and surface gravity are derived for supergiants in the range of temperature between 29700 K and 15200 K. The availability of accurate tables of calibration allows us to estimate the efficiency of the derived formulas in reproducing the observed values. The average efficiency of the new formulas, expressed in percent, is 94 for the visual magnitude, 81 for the mass, 96 for the radius, 99 for the logarithm of the luminosity and 97 for the logarithm of the surface gravity.

  12. K2 photometry and HERMES spectroscopy of the blue supergiant rho Leo

    DEFF Research Database (Denmark)

    Aerts, C.; Bowman, D. M.; Simon-Diaz, S.

    2018-01-01

    We present an 80-d long uninterrupted high-cadence K2 light curve of the B1Iab supergiant rho Leo (HD91316), deduced with the method of halo photometry. This light curve reveals a dominant frequency of f(rot) = 0.0373 d(-1) and its harmonics. This dominant frequency corresponds with a rotation...... period of 26.8 d and is subject to amplitude and phase modulation. The K2 photometry additionally reveals multiperiodic low-frequency variability (

  13. Supergiant Fast X-ray Transients with Swift: spectroscopic and temporal properties

    OpenAIRE

    Romano, P.; Mangano, V.; Ducci, L.; Esposito, P.; Farinelli, R.; Ceccobello, C.; Vercellone, S.; Burrows, D. N.; Kennea, J. A.; Krimm, H. A.; Gehrels, N.

    2012-01-01

    Supergiant fast X-ray transients (SFXTs) are a class of high-mass X-ray binaries with possible counterparts in the high energy gamma rays. The Swift SFXT Project has conducted a systematic investigation of the properties of SFTXs on timescales ranging from minutes to years and in several intensity states (from bright flares, to intermediate intensity states, and down to almost quiescence). We also performed broad-band spectroscopy of outbursts, and intensity-selected spectroscopy outside of o...

  14. SUPERGIANT SHELLS AND MOLECULAR CLOUD FORMATION IN THE LARGE MAGELLANIC CLOUD

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, J. R.; Dickey, John M. [School of Mathematics and Physics, University of Tasmania, Sandy Bay Campus, Churchill Avenue, Sandy Bay, TAS 7005 (Australia); McClure-Griffiths, N. M. [Australia Telescope National Facility, CSIRO Astronomy and Space Science, Marsfield NSW 2122 (Australia); Wong, T. [Astronomy Department, University of Illinois, Urbana, IL 61801 (United States); Hughes, A. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117, Heidelberg (Germany); Fukui, Y. [Department of Physics and Astrophysics, Nagoya University, Chikusa-ku, Nagoya (Japan); Kawamura, A., E-mail: joanne.dawson@utas.edu.au [National Astronomical Observatory of Japan, Tokyo 181-8588 (Japan)

    2013-01-20

    We investigate the influence of large-scale stellar feedback on the formation of molecular clouds in the Large Magellanic Cloud (LMC). Examining the relationship between H I and {sup 12}CO(J = 1-0) in supergiant shells (SGSs), we find that the molecular fraction in the total volume occupied by SGSs is not enhanced with respect to the rest of the LMC disk. However, the majority of objects ({approx}70% by mass) are more molecular than their local surroundings, implying that the presence of a supergiant shell does on average have a positive effect on the molecular gas fraction. Averaged over the full SGS sample, our results suggest that {approx}12%-25% of the molecular mass in supergiant shell systems was formed as a direct result of the stellar feedback that created the shells. This corresponds to {approx}4%-11% of the total molecular mass of the galaxy. These figures are an approximate lower limit to the total contribution of stellar feedback to molecular cloud formation in the LMC, and constitute one of the first quantitative measurements of feedback-triggered molecular cloud formation in a galactic system.

  15. Quantitative spectroscopy of Galactic BA-type supergiants. I. Atmospheric parameters

    Science.gov (United States)

    Firnstein, M.; Przybilla, N.

    2012-07-01

    Context. BA-type supergiants show a high potential as versatile indicators for modern astronomy. This paper constitutes the first in a series that aims at a systematic spectroscopic study of Galactic BA-type supergiants. Various problems will be addressed, including in particular observational constraints on the evolution of massive stars and a determination of abundance gradients in the Milky Way. Aims: The focus here is on the determination of accurate and precise atmospheric parameters for a sample of Galactic BA-type supergiants as prerequisite for all further analysis. Some first applications include a recalibration of functional relationships between spectral-type, intrinsic colours, bolometric corrections and effective temperature, and an exploration of the reddening-free Johnson Q and Strömgren [c1] and β-indices as photometric indicators for effective temperatures and gravities of BA-type supergiants. Methods: An extensive grid of theoretical spectra is computed based on a hybrid non-LTE approach, covering the relevant parameter space in effective temperature, surface gravity, helium abundance, microturbulence and elemental abundances. The atmospheric parameters are derived spectroscopically by line-profile fits of our theoretical models to high-resolution and high-S/N spectra obtained at various observatories. Ionization equilibria of multiple metals and the Stark-broadened hydrogen and the neutral helium lines constitute our primary indicators for the parameter determination, supplemented by (spectro-)photometry from the UV to the near-IR. Results: We obtain accurate atmospheric parameters for 35 sample supergiants from a homogeneous analysis. Data on effective temperatures, surface gravities, helium abundances, microturbulence, macroturbulence and rotational velocities are presented. The interstellar reddening and the ratio of total-to-selective extinction towards the stars are determined. Our empirical spectral-type-Teff scale is steeper than

  16. The luminosities of cool supergiants in the Magellanic Clouds, and the Humphreys-Davidson limit revisited

    Science.gov (United States)

    Davies, Ben; Crowther, Paul A.; Beasor, Emma R.

    2018-05-01

    The empirical upper luminosity boundary Lmax of cool supergiants, often referred to as the Humphreys-Davidson limit, is thought to encode information on the general mass-loss behaviour of massive stars. Further, it delineates the boundary at which single stars will end their lives stripped of their hydrogen-rich envelope, which in turn is a key factor in the relative rates of Type-II to Type-Ibc supernovae from single star channels. In this paper we have revisited the issue of Lmax by studying the luminosity distributions of cool supergiants (SGs) in the Large and Small Magellanic Clouds (LMC/SMC). We assemble samples of cool SGs in each galaxy which are highly-complete above log L/L⊙=5.0, and determine their spectral energy distributions from the optical to the mid-infrared using modern multi-wavelength survey data. We show that in both cases Lmax appears to be lower than previously quoted, and is in the region of log L/L⊙=5.5. There is no evidence for Lmax being higher in the SMC than in the LMC, as would be expected if metallicity-dependent winds were the dominant factor in the stripping of stellar envelopes. We also show that Lmax aligns with the lowest luminosity of single nitrogen-rich Wolf-Rayet stars, indicating of a change in evolutionary sequence for stars above a critical mass. From population synthesis analysis we show that the Geneva evolutionary models greatly over-predict the numbers of cool SGs in the SMC. We also argue that the trend of earlier average spectral types of cool SGs in lower metallicity environments represents a genuine shift to hotter temperatures. Finally, we use our new bolometric luminosity measurements to provide updated bolometric corrections for cool supergiants.

  17. Light variations of the population II F-type supergiant HD 46703

    Science.gov (United States)

    Bond, H. E.; Carney, B. W.; Grauer, A. D.

    1984-01-01

    Photometric monitoring has revealed brightness variations of 0.1 m on a time scale of weeks for HD 46703, a metal-deficient F-type field analog of the stars lying above the horizontal branch in globular clusters. It is suggested that HD 46703 belongs to the '89 Her' class of luminous F-type variables. Since HD 46703 is unquestionably a halo object, it is almost certainly a low-mass star. It is suggested that it, and probably the other 89 Her variables, are masquerading as supergiants during their final evolution off the asymptotic giant branch.

  18. Effect of mass loss on the driving of g-modes in B supergiant stars

    Energy Technology Data Exchange (ETDEWEB)

    Godart, Melanie; Noels, Arlette [Institut d' Astrophysique et de Geophysique, Liege (Belgium); Dupret, Marc-Antoine [Observatoire de Paris-Meudon, LESIA (France)], E-mail: Helanie.Godart@ulg.ac.be, E-mail: Arlette.Noels@ulg.ac.be, E-mail: ma.dupret@obspm.fr

    2008-10-15

    MOST has detected p and g-modes in the B supergiant star HD163899. Saio et al. (2006) have explained the driving of g-modes in a post main sequence star by the presence of a convective shell which prevents some modes from entering the damping radiative core. We show that this scenario depends on the evolution of the star, with or without mass loss. If the mass loss rate is high enough, the convective shell disappears and all the g-modes are stable.

  19. The orbital period in the supergiant fast X-ray transient IGR J16465--4507

    OpenAIRE

    Clark, D. J.; Sguera, V.; Bird, A. J; McBride, V. A.; Hill, A. B.; Scaringi, S.; Drave, S.; Bazzano, A.; Dean, A. J

    2010-01-01

    Timing analysis of the INTEGRAL-IBIS and Swift-BAT light curves of the Supergiant Fast X-ray Transient (SFXT) IGR J16465-4507 has identified a period of 30.32+/-0.02 days which we interpret as the orbital period of the binary system. In addition 11 outbursts (9 of which are previously unpublished) have been found between MJD 52652 to MJD 54764, all of which occur close to the region of the orbit we regard as periastron. From the reported flux outbursts, we found a dynamical range in the inter...

  20. On the Disappearance of the Supergiant Progenitor of SN 2011dh in M51.

    Science.gov (United States)

    Ergon, Mattias; Sollerman, Jesper; Pursimo, Tapio; Augusteijn, Thomas; Telting, John; Smirnova, Olesja; Kankare, Erkki; Mattila, Seppo; Maund, Justyn; Fraser, Morgan

    2013-03-01

    We report on high quality pre- and post-explosion B, V and r band imaging obtained with the 2.56 m Nordic Optical Telescope (NOT). Difference imaging reveals a reduction of 45-60 percent in flux at the position of the yellow supergiant coincident with SN 2011dh and proposed as the progenitor by Maund et al. (2011, ApJ, 739, L37). The pre-explosion imaging was obtained on May 26 2008 (B) and May 29 2011 (V and r), the latter just 2 days before explosion.

  1. Disappearance of the Supergiant Progenitor of SN 2011dh in M51

    Science.gov (United States)

    Van Dyk, Schuyler D.; Filippenko, Alexei V.; Fox, Ori; Kelly, Patrick; Smith, Nathan

    2013-03-01

    We report that in Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) observations at F555W and F814W with the UVIS channel, conducted on 2013 March 2 UT as part of our Cycle 20 Snapshot program GO-13029 (PI: A. Filippenko), we have discovered that the yellow supergiant star, identified by Van Dyk et al. (2011, ApJ, 741, L28) and Maund et al. (2011, MNRAS, 739, L37) at the position of the Type IIb SN 2011dh in M51, has vanished.

  2. Effect of mass loss on the driving of g-modes in B supergiant stars

    International Nuclear Information System (INIS)

    Godart, Melanie; Noels, Arlette; Dupret, Marc-Antoine

    2008-01-01

    MOST has detected p and g-modes in the B supergiant star HD163899. Saio et al. (2006) have explained the driving of g-modes in a post main sequence star by the presence of a convective shell which prevents some modes from entering the damping radiative core. We show that this scenario depends on the evolution of the star, with or without mass loss. If the mass loss rate is high enough, the convective shell disappears and all the g-modes are stable.

  3. Red-light-controllable liquid-crystal soft actuators via low-power excited upconversion based on triplet-triplet annihilation.

    Science.gov (United States)

    Jiang, Zhen; Xu, Ming; Li, Fuyou; Yu, Yanlei

    2013-11-06

    A red-light-controllable soft actuator has been achieved, driven by low-power excited triplet-triplet annihilation-based upconversion luminescence (TTA-UCL). First, a red-to-blue TTA-based upconversion system with a high absolute quantum yield of 9.3 ± 0.5% was prepared by utilizing platinum(II) tetraphenyltetrabenzoporphyrin (PtTPBP) as the sensitizer and 9,10-bis(diphenylphosphoryl)anthracene (BDPPA) as the annihilator. In order to be employed as a highly effective phototrigger of photodeformable cross-linked liquid-crystal polymers (CLCPs), the PtTPBP&BDPPA system was incorporated into a rubbery polyurethane film and then assembled with an azotolane-containing CLCP film. The generating assembly film bent toward the light source when irradiated with a 635 nm laser at low power density of 200 mW cm(-2) because the TTA-UCL was effectively utilized by the azotolane moieties in the CLCP film, inducing their trans-cis photoisomerization and an alignment change of the mesogens via an emission-reabsorption process. It is the first example of a soft actuator in which the TTA-UCL is trapped and utilized to create photomechanical effect. Such advantages of using this novel red-light-controllable soft actuator in potential biological applications have also been demonstrated as negligible thermal effect and its excellent penetration ability into tissues. This work not only provides a novel photomanipulated soft actuation material system based on the TTA-UCL technology but also introduces a new technological application of the TTA-based upconversion system in photonic devices.

  4. An HST COS 'SNAPSHOT' spectrum of the K supergiant λ Vel (K4Ib-II)

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, Kenneth G. [NASA/GSFC Code 667, Greenbelt, MD 20771 (United States); Ayres, Thomas R. [University of Colorado, CASA, 389-UCB, Boulder, CO 80309 (United States); Harper, Graham M. [School of Physics, Trinity College, Dublin 2 (Ireland); Kober, Gladys; Nielsen, Krister E.; Wahlgren, Glenn M., E-mail: Kenneth.G.Carpenter@nasa.gov [Deptartment of Physics, Catholic University of America, Washington, DC 20064 (United States)

    2014-10-10

    We present a far-ultraviolet spectrum of the K4 Ib-II supergiant λ Vel obtained with the Hubble Space Telescope's Cosmic Origins Spectrograph (COS) as a part of the SNAPshot program 'SNAPing coronal iron' (GO 11687). The observation covers a wavelength region (1326-1467 Å) not previously recorded for λ Vel at a spectral resolving power of R ∼ 20,000 and displays strong emission and absorption features, superposed on a bright chromospheric continuum. Fluorescent excitation is responsible for much of the observed emission, mainly powered by strong H I Lyα and the O I (UV 2) triplet emission near λ1304. The molecular CO and H{sub 2} fluorescences are weaker than in the early-K giant α Boo while the Fe II and Cr II lines, also pumped by H I Lyα, are stronger in λ Vel. This pattern of relative line strengths between the two stars is explained by the lower iron-group element abundance in α Boo, which weakens that star's Fe II and Cr II emission without reducing the molecular fluorescences. The λ Vel spectrum shows fluorescent Fe II, Cr II, and H{sub 2} emission similar to that observed in the M supergiant α Ori, but more numerous well-defined narrow emissions from CO. The additional CO emissions are visible in the spectrum of λ Vel since that star does not have the cool, opaque circumstellar shells that surround α Ori and produce broad circumstellar CO (A-X) band absorptions that hide those emissions in the cooler star. The presence of Si IV emission in λ Vel indicates a ∼8 × 10{sup 4} K plasma that is mixed into the cooler chromosphere. Evidence of the stellar wind is seen in the C II λλ1334,1335 lines and in the blueshifted Fe II and Ni II wind absorption lines. Line modeling using Sobolev with Exact Integration for the C II lines indicates a larger terminal velocity (∼45 versus ∼30 km s{sup –1}) and turbulence (∼27 versus <21 km s{sup –1}) with a more quickly accelerating wind (β = 0.35 versus 0.7) at the time of

  5. THE YELLOW SUPERGIANT PROGENITOR OF THE TYPE II SUPERNOVA 2011dh IN M51

    International Nuclear Information System (INIS)

    Maund, J. R.; Fraser, M.; Smartt, S. J.; Kotak, R.; Magill, L.; Ergon, M.; Sollerman, J.; Pastorello, A.; Benetti, S.; Botticella, M.-T.; Valenti, S.; Bufano, F.; Danziger, I. J.; Stephens, A. W.

    2011-01-01

    We present the detection of the putative progenitor of the Type IIb SN 2011dh in archival pre-explosion Hubble Space Telescope images. Using post-explosion Adaptive Optics imaging with Gemini NIRI+ALTAIR, the position of the supernova (SN) in the pre-explosion images was determined to within 23 mas. The progenitor candidate is consistent with an F8 supergiant star (logL/L sun = 4.92 ± 0.20 and T eff = 6000 ± 280 K). Through comparison with stellar evolution tracks, this corresponds to a single star at the end of core C-burning with an initial mass of M ZAMS = 13 ± 3 M sun . The possibility of the progenitor source being a cluster is rejected, on the basis of: (1) the source not being spatially extended, (2) the absence of excess Hα emission, and (3) the poor fit to synthetic cluster spectral energy distributions (SEDs). It is unclear if a binary companion is contributing to the observed SED, although given the excellent correspondence of the observed photometry to a single star SED we suggest that the companion does not contribute significantly. Early photometric and spectroscopic observations show fast evolution similar to the transitional Type IIb SN 2008ax and suggest that a large amount of the progenitor's hydrogen envelope was removed before explosion. Late-time observations will reveal if the yellow supergiant or the putative companion star were responsible for this SN explosion.

  6. SPECTROSCOPIC AND PHOTOMETRIC VARIABILITY IN THE A0 SUPERGIANT HR 1040

    International Nuclear Information System (INIS)

    Corliss, David J.; Morrison, Nancy D.; Adelman, Saul J.

    2015-01-01

    A time-series analysis of spectroscopic and photometric observables of the A0 Ia supergiant HR 1040 has been performed, including equivalent widths, radial velocities, and Strömgren photometric indices. The data, obtained from 1993 through 2007, include 152 spectroscopic observations from the Ritter Observatory 1 m telescope and 269 Strömgren photometric observations from the Four College Automated Photoelectric Telescope. Typical of late B- and early A-type supergiants, HR 1040 has a highly variable Hα profile. The star was found to have an intermittent active phase marked by correlation between the Hα absorption equivalent width and blue-edge radial velocity and by photospheric connections observed in correlations to equivalent width, second moment and radial velocity in Si ii λλ6347, 6371. High-velocity absorption (HVA) events were observed only during this active phase. HVA events in the wind were preceded by photospheric activity, including Si ii radial velocity oscillations 19–42 days prior to onset of an HVA event and correlated increases in Si ii W λ and second moment from 13 to 23 days before the start of the HVA event. While increases in various line equivalent widths in the wind prior to HVA events have been reported in the past in other stars, our finding of precursors in enhanced radial velocity variations in the wind and at the photosphere is a new result

  7. Molecular Abundances in the Circumstellar Envelope of Oxygen-Rich Supergiant VY Canis Majoris

    Science.gov (United States)

    Edwards, Jessica L.; Ziurys, Lucy

    2014-06-01

    A complete set of molecular abundances have been established for the Oxygen-rich circumstellar envelope (CSE) surrounding the supergiant star VY Canis Majoris (VY CMa). These data were obtained from The Arizona Radio Observatory (ARO) 1-mm spectral line survey of this object using the ARO Sub-millimeter Telescope (SMT), as well as complimentary transitions taken with the ARO 12-meter. The non-LTE radiative transfer code ESCAPADE has been used to obtain the molecular abundances and distributions in VY CMa, including modeling of the various asymmetric outflow geometries in this source. For example, SO and SO2 were determined to arise from five distinct outflows, four of which are asymmetric with respect to the central star. Abundances of these two sulfur-bearing molecules range from 3 x 10-8 - 2.5 x 10-7 for the various outflows. Similar results will be presented for molecules like CS, SiS, HCN, and SiO, as well as more exotic species like NS, PO, AlO, and AlOH. The molecular abundances between the various outflows will be compared and implications for supergiant chemistry will be discussed.

  8. Clover, Red (Trifolium pretense)

    Science.gov (United States)

    Genetic modification of plants by the insertion of transgenes can be a powerful experimental approach to answer basic questions about gene product function. This technology can also be used to make improved crop varieties for use in the field. To apply this powerful tool to red clover, an important ...

  9. A new observational tracer for high-density disc-like structures around B[e] supergiants

    Czech Academy of Sciences Publication Activity Database

    Aret, Anna; Kraus, Michaela; Muratore, M.F.; Borges Fernandes, M.

    2012-01-01

    Roč. 423, č. 1 (2012), s. 284-293 ISSN 0035-8711 R&D Projects: GA ČR GA205/08/0003; GA ČR(CZ) GAP209/11/1198 Institutional support: RVO:67985815 Keywords : circumstellar matter * emission line * Be supergiants Subject RIV: BN - Astronomy , Celestial Mechanics, Astrophysics Impact factor: 5.521, year: 2012

  10. Estimation of Scatterer Diameter by Normalized Power Spectrum of High-Frequency Ultrasonic RF Echo for Assessment of Red Blood Cell Aggregation

    Science.gov (United States)

    Fukushima, Taku; Hasegawa, Hideyuki; Kanai, Hiroshi

    2011-07-01

    Red blood cell (RBC) aggregation, as one of the determinants of blood viscosity, plays an important role in blood rheology, including the condition of blood. RBC aggregation is induced by the adhesion of RBCs when the electrostatic repulsion between RBCs weakens owing to increases in protein and saturated fatty acid levels in blood, excessive RBC aggregation leads to various circulatory diseases. This study was conducted to establish a noninvasive quantitative method for assessment of RBC aggregation. The power spectrum of ultrasonic RF echoes from nonaggregating RBCs, which shows the frequency property of scattering, exhibits Rayleigh behavior. On the other hand, ultrasonic RF echoes from aggregating RBCs contain the components of reflection, which have no frequency dependence. By dividing the measured power spectrum of echoes from RBCs in the lumen by that of echoes from a posterior wall of the vein in the dorsum manus, the attenuation property of the propagating medium and the frequency responses of transmitting and receiving transducers are removed from the former spectrum. RBC aggregation was assessed by the diameter of a scatterer, which was estimated by minimizing the square difference between the measured normalized power spectrum and the theoretical power spectrum. In this study, spherical scatterers with diameters of 5, 11, 15, and 30 µm were measured in basic experiments. The estimated scatterer diameters were close to the actual diameters. Furthermore, the transient change of the scatterer diameters were measured in an in vivo experiment with respect to a 24-year-old healthy male during the avascularization using a cuff. The estimated diameters (12-22 µm) of RBCs during avascularization were larger than the diameters (4-8 µm) at rest and after recirculation. These results show the possibility of the use of the proposed method for noninvasive assessment of RBC aggregation.

  11. Terminal velocities for a large sample of O stars, B supergiants, and Wolf-Rayet stars

    International Nuclear Information System (INIS)

    Prinja, R.K.; Barlow, M.J.; Howarth, I.D.

    1990-01-01

    It is argued that easily measured, reliable estimates of terminal velocities for early-type stars are provided by the central velocity asymptotically approached by narrow absorption features and by the violet limit of zero residual intensity in saturated P Cygni profiles. These estimators are used to determine terminal velocities, v(infinity), for 181 O stars, 70 early B supergiants, and 35 Wolf-Rayet stars. For OB stars, the values are typically 15-20 percent smaller than the extreme violet edge velocities, v(edge), while for WR stars v(infinity) = 0.76 v(edge) on average. New mass-loss rates for WR stars which are thermal radio emitters are given, taking into account the new terminal velocities and recent revisions to estimates of distances and to the mean nuclear mass per electron. The relationships between v(infinity), the surface escape velocities, and effective temperatures are examined. 67 refs

  12. The early-type strong emission-line supergiants of the Magellanic Clouds - A spectroscopic zoology

    Science.gov (United States)

    Shore, S. N.; Sanduleak, N.

    1984-01-01

    The results of a spectroscopic survey of 21 early-type extreme emission line supergiants of the Large and Small Magellanic Clouds using IUE and optical spectra are presented. The combined observations are discussed and the literature on each star in the sample is summarized. The classification procedures and the methods by which effective temperatures, bolometric magnitudes, and reddenings were assigned are discussed. The derived reddening values are given along with some results concerning anomalous reddening among the sample stars. The derived mass, luminosity, and radius for each star are presented, and the ultraviolet emission lines are described. Mass-loss rates are derived and discussed, and the implications of these observations for the evolution of the most massive stars in the Local Group are addressed.

  13. The circumstellar envelopes of F and G type supergiants in the large magellanic cloud

    International Nuclear Information System (INIS)

    Hagen, W.; Humphreys, R.M.; Stencel, R.E.

    1981-01-01

    We have obtained high-dispersion echellograms at 2.5 and 5.1 A/mm of four F and G-type supergiants (Msub(V) approximately -9) in the large Magellanic Cloud for the purpose of studying their outer atmospheres as compared to their Milky Way counterparts. Line doubling at Na I D indicates extensive circumstellar envelopes and mass loss rates in excess of 10 -5 M . yr -1 with outflow velocities of 10-60 km s -1 . Deep exposures at Ca II H and K reveal new information about the chromospheres of extragalactic stars. The presence of H and K wing emission lines augments this, and also provides an independent way of estimating Msub(V). (author)

  14. Confirmation of Element Abundance Inhomogeneity in Interstellar Matter from a Study of the O-type Supergiants HDE 226868 (Cyg X-1) and α Cam

    Science.gov (United States)

    Karitskaya, E. A.; Bochkarev, N. G.; Shimansky, V. V.; Galazutdinov, G. A.

    2011-09-01

    Chemical abundances derived for two O-type supergiants with similar parameters confirm the inhomogeneity of heavy-element distribution on a scale of 2 kpc and a lifetime of ISM superclouds exceeding 1 Gyr.

  15. Infrared Space Observatory Observations of Far-Infrared Rotational Emission Lines of Water Vapor toward the Supergiant Star VY Canis Majoris

    Science.gov (United States)

    Neufeld, David A.; Feuchtgruber, Helmut; Harwit, Martin; Melnick, Gary J.

    1999-06-01

    We report the detection of numerous far-infrared emission lines of water vapor toward the supergiant star VY Canis Majoris. A 29.5-45 μm grating scan of VY CMa, obtained using the Short-Wavelength Spectrometer (SWS) of the Infrared Space Observatory at a spectral resolving power λ/Δλ of ~2000, reveals at least 41 spectral features due to water vapor that together radiate a total luminosity of ~25 Lsolar. In addition to pure rotational transitions within the ground vibrational state, these features include rotational transitions within the (010) excited vibrational state. The spectrum also shows the 2Π1/2(J=5/2)VY CMa were carried out in the instrument's Fabry-Perot mode for three water transitions: the 725-616 line at 29.8367 μm, the 441-312 line at 31.7721 μm, and the 432-303 line at 40.6909 μm. The higher spectral resolving power λ/Δλ of approximately 30,000 thereby obtained permits the line profiles to be resolved spectrally for the first time and reveals the ``P Cygni'' profiles that are characteristic of emission from an outflowing envelope. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands, and the UK) with the participation of ISAS and NASA.

  16. Effects of deviations from local thermodynamic equilibrium in the atmospheres of F supergiants. I. Overionization of Fe I atoms

    International Nuclear Information System (INIS)

    Boyarchuk, A.A.; Lyubimkov, L.S.; Sakhibullin, N.A.

    1985-01-01

    For a number of class F supergiants and dwarfs, non-LTE calculations have been made of the Fe I-Fe II ionization balance. It is shown that deviations from local thermodynamic equilibrium lead to a strong overionization of the Fe I atoms in the upper layers of the atmosphere. This confirms the conclusion obtained by Lyubimkov and Boyarchuk on the basis of an investigation of microturbulence in F supergiants. The reason for the overionization (compared with LTE) is the nonequality of the recombination and photoionization temperatures: To recombination processes there corresponds a local temperature T(/tau/), whereas the photoionization takes place under the influence of ultraviolet radiation from deeper and hotter layers of the atmosphere. The equivalent widths of some Fe I lines have been calculated. It is shown that neglect of the overionization in the analysis of sufficiently strong lines may lead to an underestimation of the iron abundance by an order of magnitude

  17. Low-frequency photospheric and wind variability in the early-B supergiant HD 2905

    Science.gov (United States)

    Simón-Díaz, S.; Aerts, C.; Urbaneja, M. A.; Camacho, I.; Antoci, V.; Fredslund Andersen, M.; Grundahl, F.; Pallé, P. L.

    2018-04-01

    Context. Despite important advances in space asteroseismology during the last decade, the early phases of evolution of stars with masses above 15 M⊙ (including the O stars and their evolved descendants, the B supergiants) have been only vaguely explored up to now. This is due to the lack of adequate observations for a proper characterization of the complex spectroscopic and photometric variability occurring in these stars. Aim. Our goal is to detect, analyze, and interpret variability in the early-B-type supergiant HD 2905 (κ Cas, B1 Ia) using long-term, ground-based, high-resolution spectroscopy. Methods: We gather a total of 1141 high-resolution spectra covering some 2900 days with three different high-performance spectrographs attached to 1-2.6m telescopes at the Canary Islands observatories. We complement these observations with the hipparcos light curve, which includes 160 data points obtained during a time span of 1200 days. We investigate spectroscopic variability of up to 12 diagnostic lines by using the zero and first moments of the line profiles. We perform a frequency analysis of both the spectroscopic and photometric dataset using Scargle periodograms. We obtain single snapshot and time-dependent information about the stellar parameters and abundances by means of the FASTWIND stellar atmosphere code. Results: HD 2905 is a spectroscopic variable with peak-to-peak amplitudes in the zero and first moments of the photospheric lines of up to 15% and 30 km s-1, respectively. The amplitude of the line-profile variability is correlated with the line formation depth in the photosphere and wind. All investigated lines present complex temporal behavior indicative of multi-periodic variability with timescales of a few days to several weeks. No short-period (hourly) variations are detected. The Scargle periodograms of the hipparcos light curve and the first moment of purely photospheric lines reveal a low-frequency amplitude excess and a clear dominant frequency

  18. Product (RED)

    DEFF Research Database (Denmark)

    Ponte, Stefano

    2011-01-01

    ) and the consumers who buy iconic brand products to help ‘distant others’. While in many other forms of causumerism, labels or certification systems ‘prove’ that a product is just, in RED, aid celebrities provide the proof. From the consumer point of view both labels and celebrities provide a similar simplification...... of complex social, economic, and environmental processes. At the same time, we argue that there are important distinctions as well—labels and certifications are ultimately about improving the conditions of production, whereas RED is about accepting existing production and trade systems and donating......(PRODUCT)RED™ (hereafter RED) is a cobranding initiative launched in 2006 by the aid celebrity Bono to raise money from product sales to support The Global Fund to Fight AIDS, Tuberculosis and Malaria. In this paper we argue that RED is shifting the boundaries of ‘causumerism’ (shopping...

  19. Star-formation complexes in the `galaxy-sized' supergiant shell of the galaxy Holmberg I

    Science.gov (United States)

    Egorov, Oleg V.; Lozinskaya, Tatiana A.; Moiseev, Alexei V.; Smirnov-Pinchukov, Grigory V.

    2018-05-01

    We present the results of observations of the galaxy Holmberg I carried out at the Russian 6-m telescope in the narrow-band imaging, long-slit spectroscopy, and scanning Fabry-Perot interferometer modes. A detailed analysis of gas kinematics, ionization conditions, and metallicity of star-forming regions in the galaxy is presented. The aim of the paper is to analyse the propagation of star formation in the galaxy and to understand the role of the ongoing star formation in the evolution of the central `galaxy-sized' supergiant H I shell (SGS), where all regions of star formation are observed. We show that star formation in the galaxy occurs in large unified complexes rather than in individual giant H II regions. Evidence of the triggered star formation is observed both on scales of individual complexes and of the whole galaxy. We identified two supernova-remnant candidates and one late-type WN star and analysed their spectrum and surrounding-gas kinematics. We provide arguments indicating that the SGS in Holmberg I is destructing by the influence of star formation occurring on its rims.

  20. THE FIRST SPECTROPOLARIMETRIC MONITORING OF THE PECULIAR O4 Ief SUPERGIANT ζ PUPPIS

    International Nuclear Information System (INIS)

    Hubrig, S.; Ilyin, I.; Kholtygin, A.; Schöller, M.; Oskinova, L. M.

    2016-01-01

    The origin of the magnetic field in massive O-type stars is still under debate. To model the physical processes responsible for the generation of O star magnetic fields, it is important to understand whether correlations between the presence of a magnetic field and stellar evolutionary state, rotation velocity, kinematical status, and surface composition can be identified. The O4 Ief supergiant ζ Pup is a fast rotator and a runaway star, which may be a product of a past binary interaction, possibly having had an encounter with the cluster Trumper 10 some 2 Myr ago. The currently available observational material suggests that certain observed phenomena in this star may be related to the presence of a magnetic field. We acquired spectropolarimetric observations of ζ Pup with FORS 2 mounted on the 8 m Antu telescope of the Very Large Telescope to investigate if a magnetic field is indeed present in this star. We show that many spectral lines are highly variable and probably vary with the recently detected period of 1.78 day. No magnetic field is detected in ζ Pup, as no magnetic field measurement has a significance level higher than 2.4 σ . Still, we studied the probability of a single sinusoidal explaining the variation of the longitudinal magnetic field measurements.

  1. THE FIRST SPECTROPOLARIMETRIC MONITORING OF THE PECULIAR O4 Ief SUPERGIANT ζ PUPPIS

    Energy Technology Data Exchange (ETDEWEB)

    Hubrig, S.; Ilyin, I. [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam (Germany); Kholtygin, A. [Astronomical Institute, St. Petersburg State University, Universitetski pr. 28, 198504, St. Petersburg (Russian Federation); Schöller, M. [European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching (Germany); Oskinova, L. M., E-mail: shubrig@aip.de [Universität Potsdam, Institut für Physik und Astronomie, 14476 Potsdam (Germany)

    2016-05-10

    The origin of the magnetic field in massive O-type stars is still under debate. To model the physical processes responsible for the generation of O star magnetic fields, it is important to understand whether correlations between the presence of a magnetic field and stellar evolutionary state, rotation velocity, kinematical status, and surface composition can be identified. The O4 Ief supergiant ζ Pup is a fast rotator and a runaway star, which may be a product of a past binary interaction, possibly having had an encounter with the cluster Trumper 10 some 2 Myr ago. The currently available observational material suggests that certain observed phenomena in this star may be related to the presence of a magnetic field. We acquired spectropolarimetric observations of ζ Pup with FORS 2 mounted on the 8 m Antu telescope of the Very Large Telescope to investigate if a magnetic field is indeed present in this star. We show that many spectral lines are highly variable and probably vary with the recently detected period of 1.78 day. No magnetic field is detected in ζ Pup, as no magnetic field measurement has a significance level higher than 2.4 σ . Still, we studied the probability of a single sinusoidal explaining the variation of the longitudinal magnetic field measurements.

  2. Supergiant fast X-ray transients with Swift: Spectroscopic and temporal properties

    Science.gov (United States)

    Romano, P.; Mangano, V.; Ducci, L.; Esposito, P.; Farinelli, R.; Ceccobello, C.; Vercellone, S.; Burrows, D. N.; Kennea, J. A.; Krimm, H. A.; Gehrels, N.

    2012-12-01

    Supergiant fast X-ray transients (SFXTs) are a class of high-mass X-ray binaries with possible counterparts in the high energy gamma rays. The Swift SFXT Project1 has conducted a systematic investigation of the properties of SFTXs on timescales ranging from minutes to years and in several intensity states (from bright flares, to intermediate intensity states, and down to almost quiescence). We also performed broad-band spectroscopy of outbursts, and intensity-selected spectroscopy outside of outbursts. We demonstrated that while the brightest phase of the outburst only lasts a few hours, further activity is observed at lower fluxes for a remarkably longer time, up to weeks. Furthermore, we assessed the fraction of the time these sources spend in each phase, and their duty cycle of inactivity. We present the most recent results from our investigation. The spectroscopic and, most importantly, timing properties of SFXTs we have uncovered with Swift will serve as a guide in search for the high energy emission from these enigmatic objects.

  3. Triggering the formation of the supergiant H II region NGC 604 in M 33

    Science.gov (United States)

    Tachihara, Kengo; Gratier, Pierre; Sano, Hidetoshi; Tsuge, Kisetsu; Miura, Rie E.; Muraoka, Kazuyuki; Fukui, Yasuo

    2018-05-01

    Formation mechanism of a supergiant H II region NGC 604 is discussed in terms of collision of H I clouds in M 33. An analysis of the archival H I data obtained with the Very Large Array (VLA) reveals complex velocity distributions around NGC 604. The H I clouds are composed of two velocity components separated by ˜20 km s-1 for an extent of ˜700 pc, beyond the size of the the H II region. Although the H I clouds are not easily separated in velocity with some mixed component represented by merged line profiles, the atomic gas mass amounts to 6 × 106 M_{⊙} and 9 × 106 M_{⊙} for each component. These characteristics of H I gas and the distributions of dense molecular gas in the overlapping regions of the two velocity components suggest that the formation of giant molecular clouds and the following massive cluster formation have been induced by the collision of H I clouds with different velocities. Referring to the existence of a gas bridging feature connecting M 33 with M 31 reported by large-scale H I surveys, the disturbed atomic gas possibly represents the result of past tidal interaction between the two galaxies, which is analogous to the formation of the R 136 cluster in the LMC.

  4. The circumstellar shells and mass loss rates of four M supergiants

    International Nuclear Information System (INIS)

    Bernat, A.P.

    1977-01-01

    A reanalysis of the physical structure of the circumstellar gas shells of four bright M supergiants, Betelgeuse, Antares, α Herculis, and μ Cephei, has been undertaken. The observational data include old Hale Observatories plates, recent McDonald Struve telescope plates, and McDonald 2.7 m photoelectric scans. These data are analyzed in the full expanding spherical geometry formulation of the radiative transfer equation.The results of the present analysis indicate that column densities in the gas shells must be revised downward compared with the previous plane-parallel results. However, the physical extents of the shells are considerably larger than previously assumed. These extents are inferred through ionization modeling, Weymann's Ca II technique, and direct observation. Also inferred are schematic wavelength-dependent chromospheric color temperatures. These results lead to much larger mass loss rates (in the range 6.7 x 10 -7 to 4.2 x 10 -4 M/sub sun/ yr -2 ) than previously inferred. The influence of these large rates of mass loss on the evolution of both stars and the Galaxy is briefly discussed

  5. Towards realistic modelling of spectral line formation - lessons learnt from red giants

    Science.gov (United States)

    Lind, Karin

    2015-08-01

    Many decades of quantitative spectroscopic studies of red giants have revealed much about the formation histories and interlinks between the main components of the Galaxy and its satellites. Telescopes and instrumentation are now able to deliver high-resolution data of superb quality for large stellar samples and Galactic archaeology has entered a new era. At the same time, we have learnt how simplifying physical assumptions in the modelling of spectroscopic data can bias the interpretations, in particular one-dimensional homogeneity and local thermodynamic equilibrium (LTE). I will present lessons learnt so far from non-LTE spectral line formation in 3D radiation-hydrodynamic atmospheres of red giants, the smaller siblings of red supergiants.

  6. Red Sirius

    Energy Technology Data Exchange (ETDEWEB)

    Martynov, D Ya

    1976-01-01

    A hypothesis is proposed explaining the assumption that Sirius changed its colour from red in the second century to pale blue in the tenth century A.D. The hypothesis is based on the possibility of transformation of a Sirius satellite (Sirius B) from a red giant in the past to a white dwarf in the present. Such a transformation would have been accompanied by an explosion of Sirius B, which is clearly visible from the Earth. The fact that the increase in Sirius brightness by 4-5 units is not reflected in historical chronicles is attributed to the degradation of sciences in Europe in 4-10 centuries.

  7. The VLT-FLAMES Tarantula Survey . XXIV. Stellar properties of the O-type giants and supergiants in 30 Doradus

    Science.gov (United States)

    Ramírez-Agudelo, O. H.; Sana, H.; de Koter, A.; Tramper, F.; Grin, N. J.; Schneider, F. R. N.; Langer, N.; Puls, J.; Markova, N.; Bestenlehner, J. M.; Castro, N.; Crowther, P. A.; Evans, C. J.; García, M.; Gräfener, G.; Herrero, A.; van Kempen, B.; Lennon, D. J.; Maíz Apellániz, J.; Najarro, F.; Sabín-Sanjulián, C.; Simón-Díaz, S.; Taylor, W. D.; Vink, J. S.

    2017-04-01

    Context. The Tarantula region in the Large Magellanic Cloud (LMC) contains the richest population of spatially resolved massive O-type stars known so far. This unmatched sample offers an opportunity to test models describing their main-sequence evolution and mass-loss properties. Aims: Using ground-based optical spectroscopy obtained in the framework of the VLT-FLAMES Tarantula Survey (VFTS), we aim to determine stellar, photospheric and wind properties of 72 presumably single O-type giants, bright giants and supergiants and to confront them with predictions of stellar evolution and of line-driven mass-loss theories. Methods: We apply an automated method for quantitative spectroscopic analysis of O stars combining the non-LTE stellar atmosphere model fastwind with the genetic fitting algorithm pikaia to determine the following stellar properties: effective temperature, surface gravity, mass-loss rate, helium abundance, and projected rotational velocity. The latter has been constrained without taking into account the contribution from macro-turbulent motions to the line broadening. Results: We present empirical effective temperature versus spectral subtype calibrations at LMC-metallicity for giants and supergiants. The calibration for giants shows a +1kK offset compared to similar Galactic calibrations; a shift of the same magnitude has been reported for dwarfs. The supergiant calibrations, though only based on a handful of stars, do not seem to indicate such an offset. The presence of a strong upturn at spectral type O3 and earlier can also not be confirmed by our data. In the spectroscopic and classical Hertzsprung-Russell diagrams, our sample O stars are found to occupy the region predicted to be the core hydrogen-burning phase by state-of-the-art models. For stars initially more massive than approximately 60 M⊙, the giant phase already appears relatively early on in the evolution; the supergiant phase develops later. Bright giants, however, are not

  8. ISOLATED WOLF-RAYET STARS AND O SUPERGIANTS IN THE GALACTIC CENTER REGION IDENTIFIED VIA PASCHEN-α EXCESS

    International Nuclear Information System (INIS)

    Mauerhan, J. C.; Stolovy, S. R.; Cotera, A.; Dong, H.; Wang, Q. D.; Morris, M. R.; Lang, C.

    2010-01-01

    We report the discovery of 19 hot, evolved, massive stars near the Galactic center region (GCR). These objects were selected for spectroscopy owing to their detection as strong sources of Paschen-α (Pα) emission-line excess, following a narrowband imaging survey of the central 0. 0 65 x 0. 0 25 (l, b) around Sgr A* with the Hubble Space Telescope. Discoveries include six carbon-type (WC) and five nitrogen-type (WN) Wolf-Rayet stars, six O supergiants, and two B supergiants. Two of the O supergiants have X-ray counterparts having properties consistent with solitary O stars and colliding-wind binaries. The infrared photometry of 17 stars is consistent with the Galactic center distance, but 2 of them are located in the foreground. Several WC stars exhibit a relatively large infrared excess, which is possibly thermal emission from hot dust. Most of the stars appear scattered throughout the GCR, with no relation to the three known massive young clusters; several others lie near the Arches and Quintuplet clusters and may have originated within one of these systems. The results of this work bring the total sample of Wolf-Rayet (WR) stars in the GCR to 88. All sources of strong Pα excess have been identified in the area surveyed with HST, which implies that the sample of WN stars in this region is near completion, and is dominated by late (WNL) types. The current WC sample, although probably not complete, is almost exclusively dominated by late (WCL) types. The observed WR subtype distribution in the GCR is a reflection of the intrinsic rarity of early subtypes (WNE and WCE) in the inner Galaxy, an effect that is driven by metallicity.

  9. Chemistry in the final stages of stellar evolution: Millimeter and submillimeter observations of supergiants and planetary nebulae

    Science.gov (United States)

    Edwards, Jessica Louise

    High mass loss rates in evolved stars make them the major contributors to recycling processed material back into the interstellar medium. This mass loss creates large circumstellar shells, rich in molecular material. This dissertation presents millimeter and submillimeter studies of the end stages of low mass and high mass stars in order to probe their molecular content in more detail. In low mass stars, the molecular material is carried on into the planetary nebula (PN) stage. Observations of CS, HCO+, and CO in planetary nebulae (PNe) of various post-asymptotic giant branch ages have shown that molecular abundances in these objects do not significantly vary with age, as previously thought. More detailed observations of the slightly oxygen-rich PN NGC 6537 resulted in the detection of CN, HCN, HNC, CCH, CS, SO, H 2CO, HCO+ and N2H+, as well as numerous 13C isotopologues. Observations of the middle-aged PN M2-48 showed the presence of CN, HCN, HNC, CS, SO, SO2, SiO, HCO+, N2H+, and several 13C isotopologues. These observations represent the first detections of CS, SO, SO2, and SiO in any planetary nebula. The implications of these observations are discussed. A 1 mm spectral survey of the supergiant star NML Cygni has been carried out with the Arizona Radio Observatory Submillimeter Telescope resulting in the observation of 102 emission features arising from 17 different molecules and 4 unidentified features. The line profiles observed in this circumstellar shell are asymmetric and vary between different molecules, akin to what has been seen in another supergiant, VY Canis Majoris. The non-LTE radiative transfer code ESCAPADE has been used to model molecular abundances in the various asymmetric outflows of VY Canis Majoris, showing just how chemically and kinematically complex these supergiant circumstellar envelopes really are.

  10. Dense molecular clumps associated with the Large Magellanic Cloud supergiant shells LMC 4 and LMC 5

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Kosuke; Mizuno, Norikazu [Department of Astronomy, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 133-0033 (Japan); Minamidani, Tetsuhiro [Nobeyama Radio Observatory, 462-2 Nobeyama Minamimaki-mura, Minamisaku-gun, Nagano 384-1305 (Japan); Onishi, Toshikazu; Muraoka, Kazuyuki [Department of Physical Science, Osaka Prefecture University, Gakuen 1-1, Sakai, Osaka 599-8531 (Japan); Kawamura, Akiko; Muller, Erik; Tatematsu, Ken' ichi; Hasegawa, Tetsuo; Miura, Rie E.; Ezawa, Hajime [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Dawson, Joanne [Australia Telescope National Facility, CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia); Tosaki, Tomoka [Joetsu University of Education, Yamayashiki-machi, Joetsu, Niigata 943-8512 (Japan); Sakai, Takeshi [Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu, Tokyo 182-8585 (Japan); Tsukagoshi, Takashi [College of Science, Ibaraki University, Bunkyo 2-1-1, Mito 310-8512 (Japan); Tanaka, Kunihiko [Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama, Kanagawa 223-8522 (Japan); Fukui, Yasuo, E-mail: kosuke.fujii@nao.ac.jp [Department of Astrophysics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan)

    2014-12-01

    We investigate the effects of supergiant shells (SGSs) and their interaction on dense molecular clumps by observing the Large Magellanic Cloud (LMC) star-forming regions N48 and N49, which are located between two SGSs, LMC 4 and LMC 5. {sup 12}CO (J = 3-2, 1-0) and {sup 13}CO(J = 1-0) observations with the ASTE and Mopra telescopes have been carried out toward these regions. A clumpy distribution of dense molecular clumps is revealed with 7 pc spatial resolution. Large velocity gradient analysis shows that the molecular hydrogen densities (n(H{sub 2})) of the clumps are distributed from low to high density (10{sup 3}-10{sup 5} cm{sup –3}) and their kinetic temperatures (T {sub kin}) are typically high (greater than 50 K). These clumps seem to be in the early stages of star formation, as also indicated from the distribution of Hα, young stellar object candidates, and IR emission. We found that the N48 region is located in the high column density H I envelope at the interface of the two SGSs and the star formation is relatively evolved, whereas the N49 region is associated with LMC 5 alone and the star formation is quiet. The clumps in the N48 region typically show high n(H{sub 2}) and T {sub kin}, which are as dense and warm as the clumps in LMC massive cluster-forming areas (30 Dor, N159). These results suggest that the large-scale structure of the SGSs, especially the interaction of two SGSs, works efficiently on the formation of dense molecular clumps and stars.

  11. DISCOVERY OF SiO BAND EMISSION FROM GALACTIC B[e] SUPERGIANTS

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, M. [Astronomický ústav, Akademie věd České republiky, Fričova 298, 251 65 Ondřejov (Czech Republic); Oksala, M. E. [LESIA, Observatoire de Paris, CNRS UMR 8109, UPMC, Université Paris Diderot, 5 place Jules Janssen, F-92190, Meudon (France); Cidale, L. S.; Arias, M. L.; Torres, A. F. [Departamento de Espectroscopía Estelar, Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata (Argentina); Fernandes, M. Borges, E-mail: michaela.kraus@asu.cas.cz [Observatório Nacional, Rua General José Cristino 77, 20921-400 São Cristovão, Rio de Janeiro (Brazil)

    2015-02-20

    B[e] supergiants (B[e]SGs) are evolved massive stars in a short-lived transition phase. During this phase, these objects eject large amounts of material, which accumulate in a circumstellar disk-like structure. The expelled material is typically dense and cool, providing the cradle for molecule and dust condensation and for a rich, ongoing chemistry. Very little is known about the chemical composition of these disks, beyond the emission from dust and CO revolving around the star on Keplerian orbits. As massive stars preserve an oxygen-rich surface composition throughout their life, other oxygen-based molecules can be expected to form. As SiO is the second most stable oxygen compound, we initiated an observing campaign to search for first-overtone SiO emission bands. We obtained high-resolution near-infrared L-band spectra for a sample of Galactic B[e]SGs with reported CO band emission. We clearly detect emission from the SiO first-overtone bands in CPD-52 9243 and indications for faint emission in HD 62623, HD 327083, and CPD-57 2874. From model fits, we find that in all these stars the SiO bands are rotationally broadened with a velocity lower than observed in the CO band forming regions, suggesting that SiO forms at larger distances from the star. Hence, searching for and analyzing these bands is crucial for studying the structure and kinematics of circumstellar disks, because they trace complementary regions to the CO band formation zone. Moreover, since SiO molecules are the building blocks for silicate dust, their study might provide insight in the early stage of dust formation.

  12. Accretion from a clumpy massive-star wind in supergiant X-ray binaries

    Science.gov (United States)

    El Mellah, I.; Sundqvist, J. O.; Keppens, R.

    2018-04-01

    Supergiant X-ray binaries (SgXB) host a compact object, often a neutron star (NS), orbiting an evolved O/B star. Mass transfer proceeds through the intense line-driven wind of the stellar donor, a fraction of which is captured by the gravitational field of the NS. The subsequent accretion process on to the NS is responsible for the abundant X-ray emission from SgXB. They also display peak-to-peak variability of the X-ray flux by a factor of a few 10-100, along with changes in the hardness ratios possibly due to varying absorption along the line of sight. We use recent radiation-hydrodynamic simulations of inhomogeneities (a.k.a. clumps) in the non-stationary wind of massive hot stars to evaluate their impact on the time-variable accretion process. For this, we run 3D hydrodynamic simulations of the wind in the vicinity of the accretor to investigate the formation of the bow shock and follow the inhomogeneous flow over several spatial orders of magnitude, down to the NS magnetosphere. In particular, we show that the impact of the wind clumps on the time variability of the intrinsic mass accretion rate is severely tempered by the crossing of the shock, compared to the purely ballistic Bondi-Hoyle-Lyttleton estimation. We also account for the variable absorption due to clumps passing by the line of sight and estimate the final effective variability of the column density and mass accretion rate for different orbital separations. Finally, we compare our results to the most recent analysis of the X-ray flux and the hardness ratio in Vela X-1.

  13. Radio continuum emission from winds, chromospheres, and coronae of cool giants and supergiants

    International Nuclear Information System (INIS)

    Drake, S.A.; Linsky, J.L.

    1986-01-01

    In this paper we present the results of a sensitive VLA radio continuum survey at 6 cm of 39 of the nearest, single cool giants and supergiants with spectral types in the range G0--M5. We discuss our findings in the context of the various mechanisms that might be producing radio emission in these cool stars. We have definitely detected four K and M giants (α 1 Her, α Boo, rho Per, and μ Gem) and probably detected a fifth ( β UMi) at flux levels of 0.1--1.0 mJy. We believe that in all five of these cases the radio emission is thermal emission from cool stellar winds. We have made additional 2 cm observations of several stars, including the four stars definitely detected at 6 cm. We have derived spectral indices for α Boo, α 1 Her, and rho Per of 0.80, 0.84, and 0.95, respectively, that are close to the 0.6 value predicted by standard stellar wind models in the optically thick regime. An additional cool giant (α Tau) was detected only at 2 cm, implying a spectral index of > or =0.87. None of the coronal or hybrid-chromosphere giants observed were detected in this study, with the exception of α Aur, a 0.2 mJy radio source at 6 cm, which is in fact a widely separated, long-period (P/sub orb/approx.104/sup d/) RS CVn system containing two cool giant stars. In this case, we believe that the 6 cm radio emission is optically thin, thermal emission from the corona(e) of one or both of the components, since the radio-emission measure is consistent with that of the observed x-ray emission

  14. DISCOVERY OF THE FIRST B[e] SUPERGIANTS IN M 31

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, M.; Oksala, M. E. [Astronomický ústav, Akademie věd České republiky, Fričova 298, 251 65 Ondřejov (Czech Republic); Cidale, L. S.; Arias, M. L. [Departamento de Espectroscopía Estelar, Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, B1900FWA La Plata (Argentina); Borges Fernandes, M., E-mail: kraus@sunstel.asu.cas.cz [Observatório Nacional, Rua General José Cristino 77, 20921-400 São Cristovão, Rio de Janeiro (Brazil)

    2014-01-01

    B[e] supergiants (B[e]SGs) are transitional objects in the post-main sequence evolution of massive stars. The small number of B[e]SGs known so far in the Galaxy and the Magellanic Clouds indicates that this evolutionary phase is short. Nevertheless, the strong aspherical mass loss occurring during this phase, which leads to the formation of rings or disk-like structures, and the similarity to possible progenitors of SN1987 A emphasize the importance of B[e]SGs for the dynamics of the interstellar medium as well as stellar and galactic chemical evolution. The number of objects and their mass-loss behavior at different metallicities are essential ingredients for accurate predictions from stellar and galactic evolution calculations. However, B[e]SGs are not easily identified, as they share many characteristics with luminous blue variables (LBVs) in their quiescent (hot) phase. We present medium-resolution near-infrared K-band spectra for four stars in M 31, which have been assigned a hot LBV (candidate) status. Applying diagnostics that were recently developed to distinguish B[e]SGs from hot LBVs, we classify two of the objects as bonafide LBVs; one of them currently in outburst. In addition, we firmly classify the two stars 2MASS J00441709+4119273 and 2MASS J00452257+4150346 as the first B[e]SGs in M 31 based on strong CO band emission detected in their spectra, and infrared colors typical for this class of stars.

  15. Optical spectroscopy of the blue supergiant Sk-69° 279 and its circumstellar shell with SALT

    Science.gov (United States)

    Gvaramadze, V. V.; Kniazev, A. Y.; Maryeva, O. V.; Berdnikov, L. N.

    2018-02-01

    We report the results of optical spectroscopy of the blue supergiant Sk-69° 279 and its circular shell in the Large Magellanic Cloud (LMC) with the Southern African Large Telescope (SALT). We classify Sk-69° 279 as an O9.2 Iaf star and analyse its spectrum by using the stellar atmosphere code CMFGEN, obtaining a stellar temperature of ≈30 kK, a luminosity of log (L*/ L⊙) = 5.54, a mass-loss rate of log (\\dot{M}/ M_{⊙} yr^{-1}) = -5.26, and a wind velocity of 800km s-1. We found also that Sk-69° 279 possesses an extended atmosphere with an effective temperature of ≈24 kK and that its surface helium and nitrogen abundances are enhanced, respectively, by factors of ≈2 and 20-30. This suggests that either Sk-69° 279 was initially a (single) fast-rotating ( ≳ 400 km s- 1) star, which only recently evolved off the main sequence, or that it is a product of close binary evolution. The long-slit spectroscopy of the shell around Sk-69° 279 revealed that its nitrogen abundance is enhanced by the same factor as the stellar atmosphere, which implies that the shell is composed mostly of the CNO processed material lost by the star. Our findings support previous propositions that some massive stars can produce compact circumstellar shells and, presumably, appear as luminous blue variables while they are still on the main sequence or have only recently left it.

  16. THE XMM-Newton and integral observations of the Supergiant Fast X-Ray Transient IGR J16328-4726

    OpenAIRE

    Fiocchi, M.; Bazzano, A.; Natalucci, L.; Ubertini, P.; Sguera, V.; Bird, A. J.; Boon, C.M.; Persi, P.; Piro, L.

    2016-01-01

    The accretion mechanism producing the short flares observed from the Supergiant Fast X-ray Transients (SFXT) is still highly debated and forms a major part in our attempts to place these X-ray binaries in the wider context of the High Mass X-ray Binaries. We report on a 216 ks INTEGRAL observation of the SFXT IGR J16328-4726 (2014 August 24–27) simultaneous with two fixed-time observations with XMM-Newton (33 and 20 ks) performed around the putative periastron passage, in order to investigate...

  17. Power

    DEFF Research Database (Denmark)

    Elmholdt, Claus Westergård; Fogsgaard, Morten

    2016-01-01

    and creativity suggests that when managers give people the opportunity to gain power and explicate that there is reason to be more creative, people will show a boost in creative behaviour. Moreover, this process works best in unstable power hierarchies, which implies that power is treated as a negotiable....... It is thus a central point that power is not necessarily something that breaks down and represses. On the contrary, an explicit focus on the dynamics of power in relation to creativity can be productive for the organisation. Our main focus is to elaborate the implications of this for practice and theory...

  18. A SPECTROSCOPIC STUDY OF BLUE SUPERGIANT STARS IN THE SCULPTOR GALAXY NGC 55: CHEMICAL EVOLUTION AND DISTANCE

    Energy Technology Data Exchange (ETDEWEB)

    Kudritzki, R. P.; Ho, I.-T.; Bresolin, F. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Castro, N. [Department of Astronomy, University of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109 (United States); Urbaneja, M. A.; Przybilla, N. [Institut für Astro- und Teilchenphysik, Universität Innsbruck, Technikerstr. 25/8, A-6020 Innsbruck (Austria); Gieren, W.; Pietrzyński, G. [Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción (Chile)

    2016-10-01

    Low-resolution (4.5–5 Å) spectra of 58 blue supergiant stars distributed over the disk of the Magellanic spiral galaxy NGC 55 in the Sculptor group are analyzed by means of non-LTE techniques to determine stellar temperatures, gravities, and metallicities (from iron peak and α -elements). A metallicity gradient of −0.22 ± 0.06 dex/ R {sub 25} is detected. The central metallicity on a logarithmic scale relative to the Sun is [ Z ] = −0.37 ± 0.03. A chemical evolution model using the observed distribution of column densities of the stellar and interstellar medium gas mass reproduces the observed metallicity distribution well and reveals a recent history of strong galactic mass accretion and wind outflows with accretion and mass-loss rates of the order of the star formation rate. There is an indication of spatial inhomogeneity in metallicity. In addition, the relatively high central metallicity of the disk confirms that two extraplanar metal-poor H ii regions detected in previous work 1.13 to 2.22 kpc above the galactic plane are ionized by massive stars formed in situ outside the disk. For a subsample of supergiants, for which Hubble Space Telescope photometry is available, the flux-weighted gravity–luminosity relationship is used to determine a distance modulus of 26.85 ± 0.10 mag.

  19. DISCOVERY OF A POSSIBLY SINGLE BLUE SUPERGIANT STAR IN THE INTRA-CLUSTER REGION OF VIRGO CLUSTER OF GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Ohyama, Youichi; Hota, Ananda [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China)

    2013-04-20

    IC 3418 is a dwarf irregular galaxy falling into the Virgo cluster, and a 17 kpc long trail is seen behind the galaxy, which is considered to have formed due to ram pressure stripping. The trail contains compact knots and diffuse blobs of ultraviolet and blue optical emission and, thus, it is a clear site of recent star formation but in an unusual environment, surrounded by a million degree intra-cluster medium. We report on our optical spectroscopy of a compact source in the trail, SDSS J122952.66+112227.8, and show that the optical spectrum is dominated by emission from a massive blue supergiant star. If confirmed, our report would mark the farthest star with spectroscopic observation. We interpret that a massive O-type star formed in situ in the trail has evolved recently out of the main sequence into this blue supergiant phase, and now lacks any detectable spectral sign of its associated H II region. We argue that turbulence within the ram pressure striped gaseous trail may play a dominant role for the star formation within such trails.

  20. DISCOVERY OF A POSSIBLY SINGLE BLUE SUPERGIANT STAR IN THE INTRA-CLUSTER REGION OF VIRGO CLUSTER OF GALAXIES

    International Nuclear Information System (INIS)

    Ohyama, Youichi; Hota, Ananda

    2013-01-01

    IC 3418 is a dwarf irregular galaxy falling into the Virgo cluster, and a 17 kpc long trail is seen behind the galaxy, which is considered to have formed due to ram pressure stripping. The trail contains compact knots and diffuse blobs of ultraviolet and blue optical emission and, thus, it is a clear site of recent star formation but in an unusual environment, surrounded by a million degree intra-cluster medium. We report on our optical spectroscopy of a compact source in the trail, SDSS J122952.66+112227.8, and show that the optical spectrum is dominated by emission from a massive blue supergiant star. If confirmed, our report would mark the farthest star with spectroscopic observation. We interpret that a massive O-type star formed in situ in the trail has evolved recently out of the main sequence into this blue supergiant phase, and now lacks any detectable spectral sign of its associated H II region. We argue that turbulence within the ram pressure striped gaseous trail may play a dominant role for the star formation within such trails.

  1. Long-lasting X-ray emission from type IIb supernova 2011dh and mass-loss history of the yellow supergiant progenitor

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Katsuda, Satoru [RIKEN (The Institute of Physical and Chemical Research) Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Bamba, Aya [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258 (Japan); Terada, Yukikatsu [Graduate School of Science and Engineering, Saitama University, Shimo-Okubo 255, Sakura, Saitama 338-8570 (Japan); Fukazawa, Yasushi, E-mail: keiichi.maeda@kusastro.kyoto-u.ac.jp [Department of Physical Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)

    2014-04-20

    Type IIb supernova (SN) 2011dh, with conclusive detection of an unprecedented yellow supergiant (YSG) progenitor, provides an excellent opportunity to deepen our understanding on the massive star evolution in the final centuries toward the SN explosion. In this paper, we report on detection and analyses of thermal X-ray emission from SN IIb 2011dh at ∼500 days after the explosion on Chandra archival data, providing a solidly derived mass-loss rate of a YSG progenitor for the first time. We find that the circumstellar media should be dense, more than that expected from a Wolf-Rayet (W-R) star by one order of magnitude. The emission is powered by a reverse shock penetrating into an outer envelope, fully consistent with the YSG progenitor but not with a W-R progenitor. The density distribution at the outermost ejecta is much steeper than that expected from a compact W-R star, and this finding must be taken into account in modeling the early UV/optical emission from SNe IIb. The derived mass-loss rate is ∼3 × 10{sup –6} M {sub ☉} yr{sup –1} for the mass-loss velocity of ∼20 km s{sup –1} in the final ∼1300 yr before the explosion. The derived mass-loss properties are largely consistent with the standard wind mass-loss expected for a giant star. This is not sufficient to be a main driver to expel nearly all the hydrogen envelope. Therefore, the binary interaction, with a huge mass transfer having taken place at ≳ 1300 yr before the explosion, is a likely scenario to produce the YSG progenitor.

  2. Toward connecting core-collapse supernova theory with observations. I. Shock revival in a 15 M ☉ blue supergiant progenitor with SN 1987A energetics

    International Nuclear Information System (INIS)

    Handy, Timothy; Plewa, Tomasz; Odrzywołek, Andrzej

    2014-01-01

    We study the evolution of the collapsing core of a 15 M ☉ blue supergiant supernova progenitor from the core bounce until 1.5 s later. We present a sample of hydrodynamic models parameterized to match the explosion energetics of SN 1987A. We find the spatial model dimensionality to be an important contributing factor in the explosion process. Compared to two-dimensional (2D) simulations, our three-dimensional (3D) models require lower neutrino luminosities to produce equally energetic explosions. We estimate that the convective engine in our models is 4% more efficient in 3D than in 2D. We propose that the greater efficiency of the convective engine found in 3D simulations might be due to the larger surface-to-volume ratio of convective plumes, which aids in distributing energy deposited by neutrinos. We do not find evidence of the standing accretion shock instability or turbulence being a key factor in powering the explosion in our models. Instead, the analysis of the energy transport in the post-shock region reveals characteristics of penetrative convection. The explosion energy decreases dramatically once the resolution is inadequate to capture the morphology of convection on large scales. This shows that the role of dimensionality is secondary to correctly accounting for the basic physics of the explosion. We also analyze information provided by particle tracers embedded in the flow and find that the unbound material has relatively long residency times in 2D models, while in 3D a significant fraction of the explosion energy is carried by particles with relatively short residency times.

  3. Neutral material around the B[e] supergiant star LHA115-S 65 An outflowing disk or a detached Keplerian rotating disk?

    Czech Academy of Sciences Publication Activity Database

    Kraus, Michaela; Borges Fernandes, M.; de Araújo, F. X.

    July, č. 517 (2010), A30/1-A30/13 ISSN 0004-6361 R&D Projects: GA AV ČR KJB300030701 Institutional research plan: CEZ:AV0Z10030501 Keywords : supergiants * circumstellar matter * outflows Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.410, year: 2010

  4. Inhomogeneous molecular ring around the B[e] supergiant LHA 120-S 73

    Science.gov (United States)

    Kraus, M.; Cidale, L. S.; Arias, M. L.; Maravelias, G.; Nickeler, D. H.; Torres, A. F.; Borges Fernandes, M.; Aret, A.; Curé, M.; Vallverdú, R.; Barbá, R. H.

    2016-10-01

    Context. B[e] supergiants are evolved massive stars, enshrouded in a dense wind and surrounded by a molecular and dusty disk. The mechanisms that drive phases of enhanced mass loss and mass ejections, responsible for the shaping of the circumstellar material of these objects, are still unclear. Aims: We aim to improve our knowledge on the structure and dynamics of the circumstellar disk of the Large Magellanic Cloud B[e] supergiant LHA 120-S 73. Methods: High-resolution optical and near-infrared spectroscopic data were obtained over a period of 16 and 7 yr, respectively. The spectra cover the diagnostic emission lines from [Ca II] and [O I], as well as the CO bands. These features trace the disk at different distances from the star. We analyzed the kinematics of the individual emission regions by modeling their emission profiles. A low-resolution mid-infrared spectrum was obtained as well, which provides information on the composition of the dusty disk. Results: All diagnostic emission features display double-peaked line profiles, which we interpret as due to Keplerian rotation. We find that the profile of each forbidden line contains contributions from two spatially clearly distinct rings. In total, we find that LHA 120-S 73 is surrounded by at least four individual rings of material with alternating densities (or by a disk with strongly non-monotonic radial density distribution). Moreover, we find that the molecular ring must have gaps or at least strong density inhomogeneities, or in other words, a clumpy structure. The optical spectra additionally display a broad emission feature at 6160-6180 Å, which we interpret as molecular emission from TiO. The mid-infrared spectrum displays features of oxygen- and carbon-rich grain species, which indicates a long-lived, stable dusty disk. We cannot confirm the previously reported high value for the stellar rotation velocity. He I λ 5876 is the only clearly detectable pure atmospheric absorption line in our data. Its

  5. Determination of electron temperature of the envelopes for the A2 Ia supergiants α Cyg and ν Cep

    International Nuclear Information System (INIS)

    Glushneva, I.N.

    1984-01-01

    On the basis of the analysis of the energy distribution data in the spectra of two bright A2 Ia supergiants, α Cyg and ω Cep, the electron temperature of the envelope and the contributions of the star and of the mantle in the continuum formation are determined. It is shown that the temperature obtained on the basis of the observations in the ultraviolet range lambda lambda 3200-3600 A is slightly higher that the effective temperature (Tsub(e) approximately 8500 K), being 12500 K in the case of α Cyg and 11000 K for ν Cep. The analysis of the α Cyg infrared excess shows that the regions with T approximately 10 4 K as well as with higher temperatures (about 2x10 4 K) exist in the envelope

  6. 2D RADIATION-HYDRODYNAMIC SIMULATIONS OF SUPERNOVA SHOCK BREAKOUT IN BIPOLAR EXPLOSIONS OF A BLUE SUPERGIANT PROGENITOR

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Akihiro; Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, 606-8502 (Japan); Shigeyama, Toshikazu [Research Center for the Early Universe, School of Science, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033 (Japan)

    2016-07-10

    A two-dimensional special relativistic radiation-hydrodynamics code is developed and applied to numerical simulations of supernova shock breakout in bipolar explosions of a blue supergiant. Our calculations successfully simulate the dynamical evolution of a blast wave in the star and its emergence from the surface. Results of the model with spherical energy deposition show a good agreement with previous simulations. Furthermore, we calculate several models with bipolar energy deposition and compare their results with the spherically symmetric model. The bolometric light curves of the shock breakout emission are calculated by a ray-tracing method. Our radiation-hydrodynamic models indicate that the early part of the shock breakout emission can be used to probe the geometry of the blast wave produced as a result of the gravitational collapse of the iron core.

  7. Einstein Observatory magnitude-limited X-ray survey of late-type giant and supergiant stars

    Science.gov (United States)

    Maggio, A.; Vaiana, G. S.; Haisch, B. M.; Stern, R. A.; Bookbinder, J.

    1990-01-01

    Results are presented of an extensive X-ray survey of 380 giant and supergiant stars of spectral types from F to M, carried out with the Einstein Observatory. It was found that the observed F giants or subgiants (slightly evolved stars with a mass M less than about 2 solar masses) are X-ray emitters at the same level of main-sequence stars of similar spectral type. The G giants show a range of emissions more than 3 orders of magnitude wide; some single G giants exist with X-ray luminosities comparable to RS CVn systems, while some nearby large G giants have upper limits on the X-ray emission below typical solar values. The K giants have an observed X-ray emission level significantly lower than F and F giants. None of the 29 M giants were detected, except for one spectroscopic binary.

  8. Moving Forward with Computational Red Teaming

    Science.gov (United States)

    2012-07-01

    Red Teaming is used across both public and private sectors and is not the sole domain of the military. Red Team Consulting (2011) notes that “the use...open for review. Consider also the context of application. Oh (2009) explains how globalisation , the rise of emerging powers, environmental

  9. BROAD BALMER WINGS IN BA HYPER/SUPERGIANTS DISTORTED BY DIFFUSE INTERSTELLAR BANDS: FIVE EXAMPLES IN THE 30 DORADUS REGION FROM THE VLT-FLAMES TARANTULA SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Walborn, Nolan R.; Sana, Hugues; Sabbi, Elena, E-mail: walborn@stsci.edu, E-mail: hsana@stsci.edu, E-mail: sabbi@stsci.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

    2015-08-10

    Extremely broad emission wings at Hβ and Hα have been found in VLT-FLAMES Tarantula Survey data for five very luminous BA supergiants in or near 30 Doradus in the Large Magellanic Cloud. The profiles of both lines are extremely asymmetrical, which we have found to be caused by very broad diffuse interstellar bands (DIBs) in the longward wing of Hβ and the shortward wing of Hα. These DIBs are well known to interstellar but not to many stellar specialists, so that the asymmetries may be mistaken for intrinsic features. The broad emission wings are generally ascribed to electron scattering, although we note difficulties for that interpretation in some objects. Such profiles are known in some Galactic hyper/supergiants and are also seen in both active and quiescent Luminous Blue Variables (LBVs). No prior or current LBV activity is known in these 30 Dor stars, although a generic relationship to LBVs is not excluded; subject to further observational and theoretical investigation, it is possible that these very luminous supergiants are approaching the LBV stage for the first time. Their locations in the HRD and presumed evolutionary tracks are consistent with that possibility. The available evidence for spectroscopic variations of these objects is reviewed, while recent photometric monitoring does not reveal variability. A search for circumstellar nebulae has been conducted, with an indeterminate result for one of them.

  10. Fuel saving and emissions cut through shore-side power concept for high-speed crafts at the red sea in egypt

    Science.gov (United States)

    Seddiek, Ibrahim S.; Mosleh, Mosaad A.; Banawan, Adel A.

    2013-12-01

    The progress of economic globalization, the rapid growth of international trade, and the maritime transportation has played an increasingly significant role in the international supply chain. As a result, worldwide seaports have suffered from a central problem, which appears in the form of massive amounts of fuel consumed and exhaust gas fumes emitted from the ships while berthed. Many ports have taken the necessary precautions to overcome this problem, while others still suffer due to the presence of technical and financial constraints. In this paper, the barriers, interconnection standards, rules, regulations, power sources, and economic and environmental analysis related to ships, shore-side power were studied in efforts to find a solution to overcome his problem. As a case study, this paper investigates the practicability, costs and benefits of switching from onboard ship auxiliary engines to shore-side power connection for high-speed crafts called Alkahera while berthed at the port of Safaga, Egypt. The results provide the national electricity grid concept as the best economical selection with 49.03 percent of annual cost saving. Moreover, environmentally, it could achieve an annual reduction in exhaust gas emissions of CO2, CO, NO x , P.M, and SO2 by 276, 2.32, 18.87, 0.825 and 3.84 tons, respectively.

  11. Power quality. Analysis of the losses related to the tension and current distortion in the electric network; Calidad de la energia electrica. Analisis de las perdidas relacionadas con la distorsion de la tension y corriente de la red electrica

    Energy Technology Data Exchange (ETDEWEB)

    Rauch Sitar, Vladimir [Universidad Autonoma de Queretaro, Facultad de Ingenieria, Queretaro (Mexico)

    1994-12-31

    In recent times every day one speaks more about power quality and about the losses produced by the tension and current distortion. The distortion in the electric network and the consumption tend to keep on increasing, and each day there will be the need of applying more resources to handle it inside a reasonable range. In this article the situation of the power quality is analyzed in the most general case and also simplified for special cases. On base on the distortion coefficients of tension and current a matrix is created where the harmonics coefficients of tension as well as the current appear in an organized form an all of the elements of that matrix are analyzed. Some topological rules are created in order to give the simplest orientation in the complex situation. The article is useful to supervise the power quality in all of the typical cases and establish a base for a more detailed analysis. [Espanol] En los ultimos tiempos cada dia mas se esta hablando sobre la calidad de la energia electrica (Power Quality) y sobre las perdidas provocadas con este factor. La distorsion de la red electrica y del consumo tiene la tendencia de seguir aumentando y cada dia mas habra que dedicar mas recursos para manejarla dentro de un rango razonable. En el articulo presentado se analiza la situacion de la calidad de energia en caso mas general y tambien simplificada para los casos especiales. A base de coeficientes de distorsion, de tension y corriente se crea una Matriz donde figuran tanto los coeficientes de armonicas de tension como de corriente en una forma ordenada y se analizan todos los elementos de esta matriz. Se crean algunas reglas topologicas para dar la orientacion mas simple en la situacion compleja. El articulo sirve para dar supervision a la calidad de energia en todos los casos tipicos y establecer una base para el analisis mas detallado.

  12. On the cosmic ray spectrum from type II Supernovae expanding in their red giant presupernova wind

    Science.gov (United States)

    Cardillo, Martina

    2015-12-01

    While from the energetic point of view SNRs are viable sources of Galactic CRs, the issue of whether they can accelerate protons up to PeV remains unsolved. Here we discuss particle acceleration at the forward shock of SN and discuss the possibility that the escaping particle current may excite a non-resonant instability that in turn leads to the formation of resonant modes confining particles close to the shock and increasing the maximum energy. This mechanism works throughout the expansion of the SN explosion, from the ejecta dominated (ED) to the Sedov-Taylor (ST) phase. Because of their higher explosion rate,we focus on type II SNae expanding in the slow, dense red supergiant wind. When the explosion occurs in such winds, the transition between the ED and the ST phase is likely to take place within a few tens of years. As a result, the spectrum of accelerated particles shows a break in the slope, at the maximum energy (EM) achieved at the beginning of the ST phase. Above this energy, the spectrum becomes steeper but remains a power law than developing an exponential cutoff. We show that for type II SNae typical parameters, proton EM can easily reach PeV energies, confirming that type II SNRs are the best candidate sources for CRs at the knee. We have tried to fit KASCADE-Grande, ARGO -YBJ and YAC1-Tibet Array data with our model but we could not find any parameter combination that could explain all data sets. Indeed the recent measurement of the proton and helium spectra in the knee region, with the ARGO-YBJ and YAC1-Tibet Array, has made the situation very confused. These measurements suggest that the knee in the light component is at 650 TeV, appreciably below the overall spectrum knee. This finding would resolve the problem of reaching very high energies in SNae, but, on the other hand, it would open a critical issue in the transition region between Galactic and extragalactic CRs.

  13. K2 photometry and HERMES spectroscopy of the blue supergiant ρ Leo: rotational wind modulation and low-frequency waves

    Science.gov (United States)

    Aerts, C.; Bowman, D. M.; Símon-Díaz, S.; Buysschaert, B.; Johnston, C.; Moravveji, E.; Beck, P. G.; De Cat, P.; Triana, S.; Aigrain, S.; Castro, N.; Huber, D.; White, T.

    2018-05-01

    We present an 80-d long uninterrupted high-cadence K2 light curve of the B1Iab supergiant ρ Leo (HD 91316), deduced with the method of halo photometry. This light curve reveals a dominant frequency of frot = 0.0373 d-1 and its harmonics. This dominant frequency corresponds with a rotation period of 26.8 d and is subject to amplitude and phase modulation. The K2 photometry additionally reveals multiperiodic low-frequency variability (<1.5 d-1) and is in full agreement with low-cadence high-resolution spectroscopy assembled during 1800 d. The spectroscopy reveals rotational modulation by a dynamic aspherical wind with an amplitude of about 20 km s-1 in the H α line, as well as photospheric velocity variations of a few km s-1 at frequencies in the range 0.2-0.6 d-1 in the Si III 4567 Å line. Given the large macroturbulence needed to explain the spectral line broadening of the star, we interpret the detected photospheric velocity as due to travelling superinertial low-degree large-scale gravity waves with dominant tangential amplitudes and discuss why ρ Leo is an excellent target to study how the observed photospheric variability propagates into the wind.

  14. Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles - I. Theoretical model - Mass-loss history unravelled in VYCMa

    NARCIS (Netherlands)

    Decin, L.; Hony, S.; de Koter, A.; Justtanont, K.; Tielens, A. G. G. M.; Waters, L. B. F. M.

    Context. Mass loss plays a dominant role in the evolution of low mass stars while they are on the Asymptotic Giant Branch (AGB). The gas and dust ejected during this phase are a major source in the mass budget of the interstellar medium. Recent studies have pointed towards the importance of

  15. Red blood cell production

    Science.gov (United States)

    ... bone marrow of bones. Stem cells in the red bone marrow called hemocytoblasts give rise to all of the formed elements in blood. If a hemocytoblast commits to becoming a cell called a proerythroblast, it will develop into a new red blood cell. The formation of a red blood ...

  16. Possible mechanism for mass transfer in X-ray binary systems with OB supergiant companions

    International Nuclear Information System (INIS)

    Alme, M.L.; Wilson, J.R.

    1976-01-01

    We have studied the ''beginning Roche lobe overflow'' phase of mass transfer. We find that before the primary fills its Roche lobe, radiation-driven density waves generated in the atmosphere produce a sufficient mass outflow rate to power a compact X-ray source. In particular, for a model of Cygnus X-1, if the radius of the photosphere is between 82 and 86 percent of the radius of the Roche equipotential, large-amplitude density waves with irregular periods of a few days are observed. These density waves, which are generated by radiation pressure effects, pass through the inner Lagrangian point with velocities approx.100 km s -1 , and can easily provide sufficient material to power the compact X-ray source

  17. Effects of coronal regions on the x-ray flux and ionization conditions in the winds of ob supergiants and of stars

    International Nuclear Information System (INIS)

    Cassinelli, J.P.; Olson, G.L.

    1979-01-01

    The anomalously strong O VI and N V lines in O stars and the C IV lines in B supergiants may be due to Auger ionization by X-rays from a thin coronal zone at the base of the cool stellar winds. We determine the size of a corona that is necessary to produce the overall ionization conditions in zeta Pup as has been deduced by Olson from line profile analysis. In the ionization balance calculations we account for diffuse radiation field in the wind and for the large optical depths in the He II continuum due to radiative and Auger ionization edges of abundant elements. The X-ray flux transmitted through the wind is calculated and compared with upper limits derived for upper limits derived for zeta Pup observations from ANS and Uhuru satellites. It is found that a coronal zone with a temperature of 5x10 6 K and a volume emission measure of 10 58 cm -3 can produce the required ionization in a wind having a temperature of 30,000--35,000 K. The emergent X-ray flux bears little resemblance to the coronal emissivity because of the opacity of the wind. The X-ray flux nearly reaches the upper limits derived from the ANS observations and, at several energy bands, should be detectable by the HEAO B satellite. A simplified analysis of the Auger ionization process is developed and applied to other Of and OB supergiants. We find that the model can explain the presence of C IV and Si IV in supergaints with effective temperatures as low as 12,000 K and can explain the appearance of O VI and N V lines in early type supergiants as late as BO.5 and B2, respectively

  18. Resolving the Circumstellar Environment of the Galactic B[e] Supergiant Star MWC 137 from Large to Small Scales

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, Michaela; Nickeler, Dieter H. [Astronomický ústav, Akademie věd České republiky, v.v.i., Fričova 298, 251 65 Ondřejov (Czech Republic); Liimets, Tiina [Tartu Observatory, 61602 Tõravere, Tartumaa (Estonia); Cappa, Cristina E.; Duronea, Nicolas U. [Instituto Argentino de Radioastronomía, CONICET, CCT-La Plata, C.C.5., 1894, Villa Elisa (Argentina); Cidale, Lydia S.; Arias, Maria L. [Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900, La Plata (Argentina); Gunawan, Diah S.; Maravelias, Grigoris; Curé, Michel [Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Av. Gran Bretaña 1111, Casilla 5030, Valparaíso (Chile); Oksala, Mary E. [California Lutheran University, Department of Physics, Thousand Oaks, CA 91360 (United States); Fernandes, Marcelo Borges [Observatório Nacional, Rua General José Cristino 77, 20921-400 São Cristovão, Rio de Janeiro (Brazil); Santander-García, Miguel, E-mail: michaela.kraus@asu.cas.cz [Observatorio Astronómico Nacional (IGN), C/Alfonso XII 3, E-28014, Madrid (Spain)

    2017-11-01

    The Galactic object MWC 137 has been suggested to belong to the group of B[e] supergiants. However, with its large-scale optical bipolar ring nebula and high-velocity jet and knots, it is a rather atypical representative of this class. We performed multiwavelength observations spreading from the optical to the radio regimes. Based on optical imaging and long-slit spectroscopic data, we found that the northern parts of the large-scale nebula are predominantly blueshifted, while the southern regions appear mostly redshifted. We developed a geometrical model consisting of two double cones. Although various observational features can be approximated with such a scenario, the observed velocity pattern is more complex. Using near-infrared integral-field unit spectroscopy, we studied the hot molecular gas in the vicinity of the star. The emission from the hot CO gas arises in a small-scale disk revolving around the star on Keplerian orbits. Although the disk itself cannot be spatially resolved, its emission is reflected by the dust arranged in arc-like structures and the clumps surrounding MWC 137 on small scales. In the radio regime, we mapped the cold molecular gas in the outskirts of the optical nebula. We found that large amounts of cool molecular gas and warm dust embrace the optical nebula in the east, south, and west. No cold gas or dust was detected in the north and northwestern regions. Despite the new insights into the nebula kinematics gained from our studies, the real formation scenario of the large-scale nebula remains an open issue.

  19. Ultraviolet spectroscopy of the blue supergiant SBW1: the remarkably weak wind of a SN 1987A analogue

    Science.gov (United States)

    Smith, Nathan; Groh, Jose H.; France, Kevin; McCray, Richard

    2017-06-01

    The Galactic blue supergiant SBW1 with its circumstellar ring nebula represents the best known analogue of the progenitor of SN 1987A. High-resolution imaging has shown Hα and infrared structures arising in an ionized flow that partly fills the ring's interior. To constrain the influence of the stellar wind on this structure, we obtained an ultraviolet (UV) spectrum of the central star of SBW1 with the Hubble Space Telescope Cosmic Origins Spectrograph. The UV spectrum shows none of the typical wind signatures, indicating a very low mass-loss rate. Radiative transfer models suggest an extremely low rate below 10-10 M⊙ yr-1, although we find that cooling time-scales probably become comparable to (or longer than) the flow time below 10-8 M⊙ yr-1. We therefore adopt this latter value as a conservative upper limit. For the central star, the model yields Teff = 21 000 ± 1000 K, log(geff) = 3.0, L ≃ 5 × 104 L⊙, and roughly Solar composition except for enhanced N abundance. SBW1's very low mass-loss rate may hinder the wind's ability to shape its nebula and to shed angular momentum. The spin-down time-scale for magnetic breaking is more than 500 times longer than the age of the ring. This, combined with the star's slow rotation rate, constrains merger scenarios to form ring nebulae. The mass-loss rate is at least 10 times lower than expected from mass-loss recipes, without any account of clumping. The physical explanation for why SBW1's wind is so weak presents an interesting mystery.

  20. Resolving the Circumstellar Environment of the Galactic B[e] Supergiant Star MWC 137 from Large to Small Scales

    International Nuclear Information System (INIS)

    Kraus, Michaela; Nickeler, Dieter H.; Liimets, Tiina; Cappa, Cristina E.; Duronea, Nicolas U.; Cidale, Lydia S.; Arias, Maria L.; Gunawan, Diah S.; Maravelias, Grigoris; Curé, Michel; Oksala, Mary E.; Fernandes, Marcelo Borges; Santander-García, Miguel

    2017-01-01

    The Galactic object MWC 137 has been suggested to belong to the group of B[e] supergiants. However, with its large-scale optical bipolar ring nebula and high-velocity jet and knots, it is a rather atypical representative of this class. We performed multiwavelength observations spreading from the optical to the radio regimes. Based on optical imaging and long-slit spectroscopic data, we found that the northern parts of the large-scale nebula are predominantly blueshifted, while the southern regions appear mostly redshifted. We developed a geometrical model consisting of two double cones. Although various observational features can be approximated with such a scenario, the observed velocity pattern is more complex. Using near-infrared integral-field unit spectroscopy, we studied the hot molecular gas in the vicinity of the star. The emission from the hot CO gas arises in a small-scale disk revolving around the star on Keplerian orbits. Although the disk itself cannot be spatially resolved, its emission is reflected by the dust arranged in arc-like structures and the clumps surrounding MWC 137 on small scales. In the radio regime, we mapped the cold molecular gas in the outskirts of the optical nebula. We found that large amounts of cool molecular gas and warm dust embrace the optical nebula in the east, south, and west. No cold gas or dust was detected in the north and northwestern regions. Despite the new insights into the nebula kinematics gained from our studies, the real formation scenario of the large-scale nebula remains an open issue.

  1. Magnetic confinement, Alfven wave reflection, and the origins of X-ray and mass-loss 'dividing lines' for late-type giants and supergiants

    Science.gov (United States)

    Rosner, R.; An, C.-H.; Musielak, Z. E.; Moore, R. L.; Suess, S. T.

    1991-01-01

    A simple qualitative model for the origin of the coronal and mass-loss dividing lines separating late-type giants and supergiants with and without hot, X-ray-emitting corona, and with and without significant mass loss is discussed. The basic physical effects considered are the necessity of magnetic confinement for hot coronal material on the surface of such stars and the large reflection efficiency for Alfven waves in cool exponential atmospheres. The model assumes that the magnetic field geometry of these stars changes across the observed 'dividing lines' from being mostly closed on the high effective temperature side to being mostly open on the low effective temperature side.

  2. IGR J17544-2619 IN DEPTH WITH SUZAKU: DIRECT EVIDENCE FOR CLUMPY WINDS IN A SUPERGIANT FAST X-RAY TRANSIENT

    International Nuclear Information System (INIS)

    Rampy, Rachel A.; Smith, David M.; Negueruela, Ignacio

    2009-01-01

    We present direct evidence for dense clumps of matter in the companion wind in a Supergiant Fast X-ray Transient (SFXT) binary. This is seen as a brief period of enhanced absorption during one of the bright, fast flares that distinguish these systems. The object under study was IGR J17544-2619, and a total of 236 ks of data were accumulated with the Japanese satellite Suzaku. The activity in this period spans a dynamic range of almost 10 4 in luminosity and gives a detailed look at SFXT behavior.

  3. Models for power transformers monitoring in the intelligent electrical network: humidity and temperature of bubble generation; Modelos para el monitoreo de transformadores de potencia en la red electrica inteligente: humedad y temperatura de generacion de burbujas

    Energy Technology Data Exchange (ETDEWEB)

    Linan Garcia, Roberto; Ponce Noyola, David; Guzman Lopez, Arali [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Betancourt Ramirez, Enrique; Tamez Torres, Gerardo [PROLEC GE, (Mexico)

    2013-03-01

    This paper presents the development of two experimental models in order to ensure reliable operation of power transformers under emergency overload conditions. The first model estimates the moisture distribution in the transformer windings, while the second model estimates the safe operating temperature and time before steam bubbles generation presents. Additionally, an electronic device was designed and built, using the models developed, in order to monitor in real time both parameters. This device allows a more reliable operation of the transmission network, considering the transformers condition. [Spanish] Este documento presenta el desarrollo de dos modelos experimentales para asegurar la operacion confiable de transformadores de potencia bajo condiciones de sobrecarga de emergencia. El primer modelo estima la temperatura de operacion segura y el tiempo antes de que ocurra la generacion de burbujas de vapor. Ademas, se diseno y construyo un dispositivo electronico, usando los modelos desarrollados, con el fin de monitorear en tiempo real ambos parametros. Este dispositivo permite una operacion mas confiable de la red de transmision, considerando la condicion de los transformadores.

  4. Red Wine Polyphenols for Cancer Prevention

    Science.gov (United States)

    He, Shan; Sun, Cuirong; Pan, Yuanjiang

    2008-01-01

    Conventional cancer therapies, the second leading cause of death worldwide, result in serious side effects and, at best, merely extend the patient's lifespan by a few years. Searching for effective prevention is of high priority in both basic and clinical sciences. In recent decades natural products have been considered to be an important source of cancer chemopreventive agents. Red wine polyphenols, which consisted of various powerful antioxidants such as flavonoids and stilbenes, have been implicated in cancer prevention and that promote human health without recognizable side effects. Since resveratrol, a major component of red wine polyphenols, has been studied and reviewed extensively for its chemopreventive activity to interfere with the multi-stage carcinogenesis, this review focuses on recent progress in studies on cancer chemopreventive activities of red wine polyphenol extracts and fractions as well as other red wine polyphenols, like procyanidin B5 analogues and myricetin. PMID:19325788

  5. Red Wine Polyphenols for Cancer Prevention

    Directory of Open Access Journals (Sweden)

    Yuanjiang Pan

    2008-05-01

    Full Text Available Conventional cancer therapies, the second leading cause of death worldwide, result in serious side effects and, at best, merely extend the patient's lifespan by a few years. Searching for effective prevention is of high priority in both basic and clinical sciences. In recent decades natural products have been considered to be an important source of cancer chemopreventive agents. Red wine polyphenols, which consisted of various powerful antioxidants such as flavonoids and stilbenes, have been implicated in cancer prevention and that promote human health without recognizable side effects. Since resveratrol, a major component of red wine polyphenols, has been studied and reviewed extensively for its chemopreventive activity to interfere with the multi-stage carcinogenesis, this review focuses on recent progress in studies on cancer chemopreventive activities of red wine polyphenol extracts and fractions as well as other red wine polyphenols, like procyanidin B5 analogues and myricetin.

  6. A FIVE-YEAR SPECTROSCOPIC AND PHOTOMETRIC CAMPAIGN ON THE PROTOTYPICAL α CYGNI VARIABLE AND A-TYPE SUPERGIANT STAR DENEB

    International Nuclear Information System (INIS)

    Richardson, N. D.; Morrison, N. D.; Kryukova, E. E.; Adelman, S. J.

    2011-01-01

    Deneb is often considered the prototypical A-type supergiant and is one of the visually most luminous stars in the Galaxy. A-type supergiants are potential extragalactic distance indicators, but the variability of these stars needs to be better characterized before this technique can be considered reliable. We analyzed 339 high-resolution echelle spectra of Deneb obtained over the five-year span of 1997 through 2001 as well as 370 Stroemgren photometric measurements obtained during the same time frame. Our spectroscopic analysis included dynamical spectra of the Hα profile, Hα equivalent widths, and radial velocities measured from Si II λλ 6347, 6371. Time-series analysis reveals no obvious cyclic behavior that proceeds through multiple observing seasons, although we found a suspected 40 day period in two, non-consecutive observing seasons. Some correlations are found between photometric and radial velocity data sets and suggest radial pulsations at two epochs. No correlation is found between the variability of the Hα profiles and that of the radial velocities or the photometry. Lucy found evidence that Deneb was a long-period single-lined spectroscopic binary star, but our data set shows no evidence for radial velocity variations caused by a binary companion.

  7. Inquiring into Red/Red Inquiring

    Directory of Open Access Journals (Sweden)

    Ken Gale

    2013-05-01

    Full Text Available This layered account of an inquiry into ‘red’ emerged out of a collective biography workshop. In the middle of the Wiltshire countryside, an international and interdisciplinary group of scholars gathered together to write and make other things and marks on paper that asked questions of, and into, the spaces between words, people, things and their environments. We did not set out to workshop or write into or paint ‘red’ but, rather, it was red that slipped in, uninvited, and painted and wrote us. Red arose as a blush or a stain seeping amongst us that became referenced obliquely by material objects, metaphors and fairytales. The stain spread, became noticeable through our weekend together and beyond it, creating another (bright red artery vein of connection to write with.

  8. Super-luminous Type II supernovae powered by magnetars

    Science.gov (United States)

    Dessart, Luc; Audit, Edouard

    2018-05-01

    Magnetar power is believed to be at the origin of numerous super-luminous supernovae (SNe) of Type Ic, arising from compact, hydrogen-deficient, Wolf-Rayet type stars. Here, we investigate the properties that magnetar power would have on standard-energy SNe associated with 15-20 M⊙ supergiant stars, either red (RSG; extended) or blue (BSG; more compact). We have used a combination of Eulerian gray radiation-hydrodynamics and non-LTE steady-state radiative transfer to study their dynamical, photometric, and spectroscopic properties. Adopting magnetar fields of 1, 3.5, 7 × 1014 G and rotational energies of 0.4, 1, and 3 × 1051 erg, we produce bolometric light curves with a broad maximum covering 50-150 d and a magnitude of 1043-1044 erg s-1. The spectra at maximum light are analogous to those of standard SNe II-P but bluer. Although the magnetar energy is channelled in equal proportion between SN kinetic energy and SN luminosity, the latter may be boosted by a factor of 10-100 compared to a standard SN II. This influence breaks the observed relation between brightness and ejecta expansion rate of standard Type II SNe. Magnetar energy injection also delays recombination and may even cause re-ionization, with a reversal in photospheric temperature and velocity. Depositing the magnetar energy in a narrow mass shell at the ejecta base leads to the formation of a dense shell at a few 1000 km s-1, which causes a light-curve bump at the end of the photospheric phase. Depositing this energy over a broad range of mass in the inner ejecta, to mimic the effect of multi-dimensional fluid instabilities, prevents the formation of a dense shell and produces an earlier-rising and smoother light curve. The magnetar influence on the SN radiation is generally not visible prior to 20-30 d, during which one may discern a BSG from a RSG progenitor. We propose a magnetar model for the super-luminous Type II SN OGLE-SN14-073.

  9. Asteroseismology of 16,000 Kepler Red Giants

    DEFF Research Database (Denmark)

    Yu, Jie; Huber, Daniel; Bedding, Timothy R.

    2018-01-01

    (sigma(M) = 7.8%), radius (sigma(R) = 2.9%), and thus surface gravity (sigma(log g) = 0.01 dex). Thanks to the large red giant sample, we confirm that red-giant-branch (RGB) and helium-core-burning (HeB) stars collectively differ in the distribution of oscillation amplitude, granulation power, and width...

  10. Seeing Red in NGC 1978, NGC 55, and NGC 3109

    Science.gov (United States)

    Davidge, T. J.

    2018-04-01

    red supergiants (RSGs) rather than C stars. The NGC 3109 observations sample three different parts of that galaxy but have a low signal-to-noise ratio. Comparisons with models suggest that the light from the NGC 3109 disk at red wavelengths is dominated by RSGs with ages of at most a few tens of Myr, in qualitative agreement with SFHs that are based on photometric measurements.

  11. Next generation red teaming

    CERN Document Server

    Dalziel, Henry

    2015-01-01

    Red Teaming is can be described as a type of wargaming.In private business, penetration testers audit and test organization security, often in a secretive setting. The entire point of the Red Team is to see how weak or otherwise the organization's security posture is. This course is particularly suited to CISO's and CTO's that need to learn how to build a successful Red Team, as well as budding cyber security professionals who would like to learn more about the world of information security. Teaches readers how to dentify systemic security issues based on the analysis of vulnerability and con

  12. Resolving the Circumstellar Environment of the Galactic B[e] Supergiant Star MWC 137 from Large to Small Scales

    Science.gov (United States)

    Kraus, Michaela; Liimets, Tiina; Cappa, Cristina E.; Cidale, Lydia S.; Nickeler, Dieter H.; Duronea, Nicolas U.; Arias, Maria L.; Gunawan, Diah S.; Oksala, Mary E.; Borges Fernandes, Marcelo; Maravelias, Grigoris; Curé, Michel; Santander-García, Miguel

    2017-11-01

    The Galactic object MWC 137 has been suggested to belong to the group of B[e] supergiants. However, with its large-scale optical bipolar ring nebula and high-velocity jet and knots, it is a rather atypical representative of this class. We performed multiwavelength observations spreading from the optical to the radio regimes. Based on optical imaging and long-slit spectroscopic data, we found that the northern parts of the large-scale nebula are predominantly blueshifted, while the southern regions appear mostly redshifted. We developed a geometrical model consisting of two double cones. Although various observational features can be approximated with such a scenario, the observed velocity pattern is more complex. Using near-infrared integral-field unit spectroscopy, we studied the hot molecular gas in the vicinity of the star. The emission from the hot CO gas arises in a small-scale disk revolving around the star on Keplerian orbits. Although the disk itself cannot be spatially resolved, its emission is reflected by the dust arranged in arc-like structures and the clumps surrounding MWC 137 on small scales. In the radio regime, we mapped the cold molecular gas in the outskirts of the optical nebula. We found that large amounts of cool molecular gas and warm dust embrace the optical nebula in the east, south, and west. No cold gas or dust was detected in the north and northwestern regions. Despite the new insights into the nebula kinematics gained from our studies, the real formation scenario of the large-scale nebula remains an open issue. Based on observations collected with (1) the ESO VLT Paranal Observatory under programs 094.D-0637(B) and 097.D-0033(A), (2) the MPG 2.2 m telescope at La Silla Observatory, Chile, under programs 096.A-9030(A) and 096.A-9039(A), (3) 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

  13. red flour beetle

    African Journals Online (AJOL)

    STORAGESEVER

    2009-12-01

    Dec 1, 2009 ... 2Institute of Biochemistry and Biotechnology, University of the Punjab, Lahore, Pakistan. 3Department of ... most important energy source around the globe ... T. castaneum (red flour beetle) samples were collected from rice.

  14. RED-ML

    DEFF Research Database (Denmark)

    Xiong, Heng; Liu, Dongbing; Li, Qiye

    2017-01-01

    using diverse RNA-seq datasets, we have developed a software tool, RED-ML: RNA Editing Detection based on Machine learning (pronounced as "red ML"). The input to RED-ML can be as simple as a single BAM file, while it can also take advantage of matched genomic variant information when available...... accurately detect novel RNA editing sites without relying on curated RNA editing databases. We have also made this tool freely available via GitHub . We have developed a highly accurate, speedy and general-purpose tool for RNA editing detection using RNA-seq data....... With the availability of RED-ML, it is now possible to conveniently make RNA editing a routine analysis of RNA-seq. We believe this can greatly benefit the RNA editing research community and has profound impact to accelerate our understanding of this intriguing posttranscriptional modification process....

  15. Alternate Explosions: Collapse and Accretion Events with Red Holes instead of Black Holes

    OpenAIRE

    Graber, James S.

    1999-01-01

    A red hole is "just like a black hole" except it lacks an event horizon and a singularity. As a result, a red hole emits much more energy than a black hole during a collapse or accretion event. We consider how a red hole solution can solve the "energy crisis" and power extremely energetic gamma ray bursts and hypernovae.

  16. On the Physical Significance of Infra-red Corrections to Inflationary Observables

    CERN Document Server

    Bartolo, N; Pietroni, M; Riotto, Antonio; Seery, D

    2008-01-01

    Inflationary observables, like the power spectrum, computed at one- and higher-order loop level seem to be plagued by large infra-red corrections. In this short note, we point out that these large infra-red corrections appear only in quantities which are not directly observable. This is in agreement with general expectations concerning infra-red effects.

  17. Diseño e implementación de un sistema de transferencias de datos a través de la red eléctrica de baja tensión con la interfaz Labview-arduino empleando la tecnología power line communications (PLC).

    OpenAIRE

    Ponce León, David; Santillán Aguirre, Sergio

    2016-01-01

    La propuesta del proyecto de titulación está basada en la implementación de un nuevo sistema de transferencia mediante tecnología Power Line Communications (PLC), Comunicación por la Red Eléctrica, que se fundamenta en la transmisión de información en diferentes puntos utilizando la red eléctrica ya existente de baja tensión en el Laboratorio de Telecomunicaciones, con la finalidad de contribuir con nuevas opciones de comunicación, de envío y recepción de información para aplicaciones tecnoló...

  18. Luminous and Variable Stars in M31 and M33. IV. Luminous Blue Variables, Candidate LBVs, B[e] Supergiants, and the Warm Hypergiants: How to Tell Them Apart

    Energy Technology Data Exchange (ETDEWEB)

    Humphreys, Roberta M.; Gordon, Michael S.; Hahn, David [Minnesota Institute for Astrophysics, 116 Church Street SE, University of Minnesota, Minneapolis, MN 55455 (United States); Martin, John C. [University of Illinois Springfield, Springfield, IL 62703 (United States); Weis, Kerstin, E-mail: roberta@umn.edu [Astronomical Institute, Ruhr-Universitaet Bochum (Germany)

    2017-02-10

    In this series of papers we have presented the results of a spectroscopic survey of luminous stars in the nearby spirals M31 and M33. Here, we present spectroscopy of 132 additional stars. Most have emission-line spectra, including luminous blue variables (LBVs) and candidate LBVs, Fe ii emission line stars, the B[e] supergiants, and the warm hypergiants. Many of these objects are spectroscopically similar and are often confused with each other. We examine their similarities and differences and propose the following guidelines that can be used to help distinguish these stars in future work. (1) The B[e] supergiants have emission lines of [O i] and [Fe ii] in their spectra. Most of the spectroscopically confirmed sgB[e] stars also have warm circumstellar dust in their spectral energy distributions (SEDs). (2) Confirmed LBVs do not have the [O i] emission lines in their spectra. Some LBVs have [Fe ii] emission lines, but not all. Their SEDs show free–free emission in the near-infrared but no evidence for warm dust . Their most important and defining characteristic is the S Dor-type variability. (3) The warm hypergiants spectroscopically resemble the LBVs in their dense wind state and the B[e] supergiants. However, they are very dusty. Some have [Fe ii] and [O i] emission in their spectra like the sgB[e] stars, but are distinguished by their A- and F-type absorption-line spectra. In contrast, the B[e] supergiant spectra have strong continua and few if any apparent absorption lines. Candidate LBVs should share the spectral characteristics of the confirmed LBVs with low outflow velocities and the lack of warm circumstellar dust.

  19. Red Wine Polyphenols for Cancer Prevention

    OpenAIRE

    He, Shan; Sun, Cuirong; Pan, Yuanjiang

    2008-01-01

    Conventional cancer therapies, the second leading cause of death worldwide, result in serious side effects and, at best, merely extend the patient's lifespan by a few years. Searching for effective prevention is of high priority in both basic and clinical sciences. In recent decades natural products have been considered to be an important source of cancer chemopreventive agents. Red wine polyphenols, which consisted of various powerful antioxidants such as flavonoids and stilbenes, have been ...

  20. Better to be red than blue in virtual competition

    DEFF Research Database (Denmark)

    Ilie, Andrei; Ioan, Silvia; Zagrean, Leon

    2008-01-01

    In the 2004 Olympic Games, opponents wearing red athletic uniforms were more likely to win against opponents wearing blue uniforms. To investigate whether this color bias extends to the world of virtual competition, we compared the performance of red and blue teams in a popular multiplayer first......-person-shooter (FPS) computer game. For 3 consecutive months, we collected data from a publicly available global statistics server. Outcomes from 1,347 matches played by the top 10 players on the same virtual arena were included. Red teams won 54.9% of matches, and this effect was highly significant. Our data suggest...... that joining the red team may offer a slight advantage over the blue team in virtual competition, and this should be accounted for when designing FPS games. It is likely that "seeing red" may trigger a powerful psychological distractor signal in human aggressive competition that can affect the outcome...

  1. Thermodynamic, energy efficiency, and power density analysis of reverse electrodialysis power generation with natural salinity gradients

    NARCIS (Netherlands)

    Yip, N.Y.; Vermaas, D.A.; Nijmeijer, K.; Elimelech, M.

    2014-01-01

    Reverse electrodialysis (RED) can harness the Gibbs free energy of mixing when fresh river water flows into the sea for sustainable power generation. In this study, we carry out a thermodynamic and energy efficiency analysis of RED power generation, and assess the membrane power density. First, we

  2. Skin quality in red potatoes

    Science.gov (United States)

    Attractive appearance is a highly desirable characteristic of fresh market red-skinned potatoes. The ideal red potato has a rich, uniform, deep red color. Color fading, netting, browning, and discoloration caused by skinning and disease decrease marketability and may reduce profits to growers and pa...

  3. Red alder potential in Alaska

    Science.gov (United States)

    Allen Brackley; David Nicholls; Mike Hannan

    2010-01-01

    Over the past several decades, red alder has established itself as a commercially important species in the Pacific Northwest. Once considered a weed species, red alder now commands respect within many markets, including furniture, architectural millwork, and other secondary manufactured products. Although red alder's natural range extends to southeast Alaska, an...

  4. Concentrating Solar Power Projects - Saguaro Power Plant | Concentrating

    Science.gov (United States)

    States Location: Red Rock, Arizona (Southwest USA) Owner(s): Arizona Public Service (100%) Technology Status: Currently Non-Operational Country: United States City: Red Rock State: Arizona County: Pinal : Organic Rankine Power Cycle Pressure: 323.0 psi Cooling Method: Wet cooling Turbine Efficiency: 20.7

  5. Red giants seismology

    Science.gov (United States)

    Mosser, B.; Samadi, R.; Belkacem, K.

    2013-11-01

    The space-borne missions CoRoT and Kepler are indiscreet. With their asteroseismic programs, they tell us what is hidden deep inside the stars. Waves excited just below the stellar surface travel throughout the stellar interior and unveil many secrets: how old is the star, how big, how massive, how fast (or slow) its core is dancing. This paper intends to paparazze the red giants according to the seismic pictures we have from their interiors.

  6. Multiplicar la red

    Directory of Open Access Journals (Sweden)

    John Young

    2015-01-01

    Full Text Available La tecnología comunicacional nos ha conducido precipitadamente a una existencia completamente nueva. En la carrera por crear una sociedad sustentable, una "red de redes mundiales" de computadoras personales que puedan ofrecer la primera esperanza real de acelerar ampliamente las comunicaciones. Las redes computacionales no solo sirven como un sistema de comunicación interactivo, rápido sino también como una herramienta de investigación de poderes insospechados.

  7. Asteroseismic Diagram for Subgiants and Red Giants

    Energy Technology Data Exchange (ETDEWEB)

    Gai, Ning; Tang, Yanke [College of Physics and Electronic information, Dezhou University, Dezhou 253023 (China); Yu, Peng [College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 401331 (China); Dou, Xianghua, E-mail: ning_gai@163.com, E-mail: tyk450@163.com [Shandong Provincial Key Laboratory of Biophysics, Dezhou University, Dezhou 253023 (China)

    2017-02-10

    Asteroseismology is a powerful tool for constraining stellar parameters. NASA’s Kepler mission is providing individual eigenfrequencies for a huge number of stars, including thousands of red giants. Besides the frequencies of acoustic modes, an important breakthrough of the Kepler mission is the detection of nonradial gravity-dominated mixed-mode oscillations in red giants. Unlike pure acoustic modes, mixed modes probe deeply into the interior of stars, allowing the stellar core properties and evolution of stars to be derived. In this work, using the gravity-mode period spacing and the large frequency separation, we construct the ΔΠ{sub 1}–Δ ν asteroseismic diagram from models of subgiants and red giants with various masses and metallicities. The relationship ΔΠ{sub 1}–Δ ν is able to constrain the ages and masses of the subgiants. Meanwhile, for red giants with masses above 1.5 M {sub ⊙}, the ΔΠ{sub 1}–Δ ν asteroseismic diagram can also work well to constrain the stellar age and mass. Additionally, we calculate the relative “isochrones” τ , which indicate similar evolution states especially for similar mass stars, on the ΔΠ{sub 1}–Δ ν diagram.

  8. The emission-line regions in the nucleus of NGC 1313 probed with GMOS-IFU: a supergiant/hypergiant candidate and a kinematically cold nucleus

    Science.gov (United States)

    Menezes, R. B.; Steiner, J. E.

    2017-04-01

    NGC 1313 is a bulgeless nearby galaxy, classified as SB(s)d. Its proximity allows high spatial resolution observations. We performed the first detailed analysis of the emission-line properties in the nuclear region of NGC 1313, using an optical data cube obtained with the Gemini Multi-object Spectrograph. We detected four main emitting areas, three of them (regions 1, 2 and 3) having spectra typical of H II regions. Region 1 is located very close to the stellar nucleus and shows broad spectral features characteristic of Wolf-Rayet stars. Our analysis revealed the presence of one or two WC4-5 stars in this region, which is compatible with results obtained by previous studies. Region 4 shows spectral features (as a strong Hα emission line, with a broad component) typical of a massive emission-line star, such as a luminous blue variable, a B[e] supergiant or a B hypergiant. The radial velocity map of the ionized gas shows a pattern consistent with rotation. A significant drop in the values of the gas velocity dispersion was detected very close to region 1, which suggests that the young stars there were formed from this cold gas, possibly keeping low values of velocity dispersion. Therefore, although detailed measurements of the stellar kinematics were not possible (due to the weak stellar absorption spectrum of this galaxy), we predict that NGC 1313 may also show a drop in the values of the stellar velocity dispersion in its nuclear region.

  9. Controller for the Machine-Side Power Converter of a 2kW Switched Reluctance Motor; Controlador del Convertidor Electronico de Potencia Lado Red de un Motor de Reluctancia Variable de 2kW

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, C.

    2006-12-19

    The ACE2 project deals with the development of a kynetic energy storage (KES) system for power peak shaving in high speed railway substations. This KES system consists in a double power converter which drives a switched reluctance machine (SRM) along with a flywheel operating in a wide speed range. This document presents from a technical point of view the features of the controller for the machine-side power converter of a 2kW SRM prototype. Hardware and software issues are treated in detail. (Author)

  10. Lower Red River Meadow Stream Restoration Project

    International Nuclear Information System (INIS)

    1996-05-01

    As part of a continuing effort to restore anadromous fish populations in the South Fork Clearwater River basin of Idaho, Bonneville Power Administration (BPA) proposes to fund the Lower Red River Meadow Restoration Project (Project). The Project is a cooperative effort with the Idaho Soil and Water Conservation District, Nez Perce National Forest, Idaho Department of Fish and Game (IDFG), and the Nez Perce Tribe of Idaho. The proposed action would allow the sponsors to perform stream bank stabilization, aquatic and riparian habitat improvement activities on IDFG's Red River Management Area and to secure long-term conservation contracts or agreements for conducting streambank and habitat improvement activities with participating private landowners located in the Idaho County, Idaho, study area. This preliminary Environmental Assessment (EA) examines the potential environmental effects of stabilizing the stream channel, restoring juvenile fish rearing habitat and reestablishing a riparian shrub community along the stream

  11. RedNemo

    DEFF Research Database (Denmark)

    Alkan, Ferhat; Erten, Cesim

    2017-01-01

    is their erroneous nature; they contain false-positive interactions and usually many more false-negatives. Recently, several computational methods have been proposed for network reconstruction based on topology, where given an input PPI network the goal is to reconstruct the network by identifying false...... material including source code, useful scripts, experimental data and the results are available at http://webprs.khas.edu.tr/∼cesim/Red Nemo. tar.gz CONTACT: cesim@khas.edu.tr Supplementary information: Supplementary data are available at Bioinformatics online....

  12. Deep Red (Profondo Rosso)

    CERN Multimedia

    Cine Club

    2015-01-01

    Wednesday 29 April 2015 at 20:00 CERN Council Chamber    Deep Red (Profondo Rosso) Directed by Dario Argento (Italy, 1975) 126 minutes A psychic who can read minds picks up the thoughts of a murderer in the audience and soon becomes a victim. An English pianist gets involved in solving the murders, but finds many of his avenues of inquiry cut off by new murders, and he begins to wonder how the murderer can track his movements so closely. Original version Italian; English subtitles

  13. Red DirCom

    Directory of Open Access Journals (Sweden)

    Joan Costa

    2007-01-01

    Full Text Available Catorce países congregados de manera activa, a través de una plataforma de encuentro donde se comparten conocimiento y experiencias en la gestión estratégica de la comunicación en las organizaciones. La red reconoce en el DirCom una figura clave del desarrollo corporativo en el nuevo contexto de los negocios, impulsa la exigencia ética a través de la formación y consolida la proyección profesional para posicionar la gestión integral del DirCom en Iberoamérica.

  14. Red - take a closer look.

    Directory of Open Access Journals (Sweden)

    Vanessa L Buechner

    Full Text Available Color research has shown that red is associated with avoidance of threat (e.g., failure or approach of reward (e.g., mating depending on the context in which it is perceived. In the present study we explored one central cognitive process that might be involved in the context dependency of red associations. According to our theory, red is supposed to highlight the relevance (importance of a goal-related stimulus and correspondingly intensifies the perceivers' attentional reaction to it. Angry and happy human compared to non-human facial expressions were used as goal-relevant stimuli. The data indicate that the color red leads to enhanced attentional engagement to angry and happy human facial expressions (compared to neutral ones - the use of non-human facial expressions does not bias attention. The results are discussed with regard to the idea that red induced attentional biases might explain the red-context effects on motivation.

  15. Listening to Red

    Directory of Open Access Journals (Sweden)

    Sinazo Mtshemla

    Full Text Available Following a distinction John Mowitt draws between hearing (and phonics, and listening (and sonics, this article argues that the dominant notion of listening to sound was determined by the disciplinary framework of South African history and by the deployment of a cinematic documentary apparatus, both of which have served to disable the act of listening. The conditions of this hearing, and a deafness to a reduced or bracketed listening (Chion via Schaeffer that would enable us to think the post in post-apartheid differently, is thus at the centre of our concerns here. We stage a series of screenings of expected possible soundtracks for Simon Gush's film and installation Red, simultaneously tracking the ways that sound - and particularly music and dialogue - can be shown to hold a certain way of thinking both the political history of South Africa and the politics of South African history. We conclude by listening more closely to hiss and murmur in the soundtrack to Red and suggest this has major implications for considering ways of thinking and knowing.

  16. Red Teaming: Past and Present

    National Research Council Canada - National Science Library

    Longbine, David F

    2008-01-01

    .... Key aspects of the Army red teaming definition are its emphasis on independent thinking, challenging organizational thinking, incorporating alternative perspectives, and incorporating alternative analysis...

  17. An Optical and Infrared Time-domain Study of the Supergiant Fast X-Ray Transient Candidate IC 10 X-2

    Science.gov (United States)

    Kwan, Stephanie; Lau, Ryan M.; Jencson, Jacob; Kasliwal, Mansi M.; Boyer, Martha L.; Ofek, Eran; Masci, Frank; Laher, Russ

    2018-03-01

    We present an optical and infrared (IR) study of IC 10 X-2, a high-mass X-ray binary in the galaxy IC 10. Previous optical and X-ray studies suggest that X-2 is a Supergiant Fast X-ray Transient: a large-amplitude (factor of ∼100), short-duration (hours to weeks) X-ray outburst on 2010 May 21. We analyze R- and g-band light curves of X-2 from the intermediate Palomar Transient Factory taken between 2013 July 15 and 2017 February 14 that show high-amplitude (≳1 mag), short-duration (≲8 days) flares and dips (≳0.5 mag). Near-IR spectroscopy of X-2 from Palomar/TripleSpec show He I, Paschen-γ, and Paschen-β emission lines with similar shapes and amplitudes as those of luminous blue variables (LBVs) and LBV candidates (LBVc). Mid-IR colors and magnitudes from Spitzer/Infrared Array Camera photometry of X-2 resemble those of known LBV/LBVcs. We suggest that the stellar companion in X-2 is an LBV/LBVc and discuss possible origins of the optical flares. Dips in the optical light curve are indicative of eclipses from optically thick clumps formed in the winds of the stellar counterpart. Given the constraints on the flare duration (0.02–0.8 days) and the time between flares (15.1 ± 7.8 days), we estimate the clump volume filling factor in the stellar winds, f V , to be 0.01interpret the origin of the optical flares as the accretion of clumps formed in the winds of an LBV/LBVc onto the compact object.

  18. International red meat trade.

    Science.gov (United States)

    Brester, Gary W; Marsh, John M; Plain, Ronald L

    2003-07-01

    The maturation of the US beef and pork markets and increasing consumer demands for convenience, safety, and nutrition suggests that the beef and pork industries must focus on product development and promotion. New marketing arrangements are developing that help coordinate production with consumer demands. The relative high levels of incomes in the United States are likely to increase the demands for branded products rather than increase total per capita consumption. Foreign markets represent the greatest opportunity for increased demand for commodity beef and pork products. Increasing incomes in developing countries will likely allow consumers to increase consumption of animal-source proteins. Real prices of beef and pork have declined substantially because of sagging domestic demand and increasing farm-level production technologies. Increasing US beef and pork exports have obviated some of the price declines. Pork attained a net export position from a quantity perspective in 1995. The United States continues to be a net importer of beef on a quantity basis but is close to becoming a net exporter in terms of value. By-products continue to play a critical role in determining the red meat trade balance and producer prices. The United States, however, must continue to become cost, price, and quality competitive with other suppliers and must secure additional market access if it is to sustain recent trade trends. Several trade tensions remain in the red meat industry. For example, mandated COOL will undoubtedly have domestic and international effects on the beef and pork sectors. Domestically, uncertainty regarding consumer demand responses or quality perceptions regarding product origin, as well as added processor-retailer costs will be nontrivial. How these factors balance out in terms of benefits versus costs to the industry is uncertain. From an international perspective, some beef and pork export suppliers to the United States could view required labeling as a

  19. RED AND DEAD: THE PROGENITOR OF SN 2012aw IN M95

    International Nuclear Information System (INIS)

    Fraser, M.; Maund, J. R.; Smartt, S. J.; Inserra, C.; Kotak, R.; Reilly, E.; Botticella, M.-T.; Dall'Ora, M.; Tomasella, L.; Benetti, S.; Ciroi, S.; Ochner, P.; Pastorello, A.; Valenti, S.; Eldridge, J. J.; Ergon, M.; Sollerman, J.; Taddia, F.; Mattila, S.; Stephens, A.

    2012-01-01

    Core-collapse supernovae (SNe) are the spectacular finale to massive stellar evolution. In this Letter, we identify a progenitor for the nearby core-collapse SN 2012aw in both ground-based near-infrared and space-based optical pre-explosion imaging. The SN itself appears to be a normal Type II Plateau event, reaching a bolometric luminosity of 10 42 erg s –1 and photospheric velocities of ∼11,000 km s –1 from the position of the Hβ P-Cygni minimum in the early SN spectra. We use an adaptive optics image to show that the SN is coincident to within 27 mas with a faint, red source in pre-explosion HST+WFPC2, VLT+ISAAC, and NTT+SOFI images. The source has magnitudes F555W = 26.70 ± 0.06, F814W = 23.39 ± 0.02, J = 21.1 ± 0.2, K = 19.1 ± 0.4, which, when compared to a grid of stellar models, best matches a red supergiant. Interestingly, the spectral energy distribution of the progenitor also implies an extinction of A V > 1.2 mag, whereas the SN itself does not appear to be significantly extinguished. We interpret this as evidence for the destruction of dust in the SN explosion. The progenitor candidate has a luminosity between 5.0 and 5.6 log L/L ☉ , corresponding to a zero-age main-sequence mass between 14 and 26 M ☉ (depending on A V ), which would make this one of the most massive progenitors found for a core-collapse SN to date.

  20. Pulsating red variables

    International Nuclear Information System (INIS)

    Whitelock, P.A.

    1990-01-01

    The observational characteristics of pulsating red variables are reviewed with particular emphasis on the Miras. These variables represent the last stage in the evolution of stars on the Asymptotic Giant Branch (AGB). A large fraction of the IRAS sources in the Bulge are Mira variables and a subset of these are also OH/IR sources. Their periods range up to 720 days, though most are between 360 and 560 days. At a given period those stars with the highest pulsation amplitudes have the highest mass-loss rates; this is interpreted as evidence for a causal connection between mass-loss and pulsation. It is suggested that once an AGB star has become a Mira it will evolve with increasing pulsation amplitude and mass-loss, but with very little change of luminosity or logarithmic period. 26 refs

  1. Red Dragon drill missions to Mars

    Science.gov (United States)

    Heldmann, Jennifer L.; Stoker, Carol R.; Gonzales, Andrew; McKay, Christopher P.; Davila, Alfonso; Glass, Brian J.; Lemke, Larry L.; Paulsen, Gale; Willson, David; Zacny, Kris

    2017-12-01

    We present the concept of using a variant of a Space Exploration Technologies Corporation (SpaceX) Dragon space capsule as a low-cost, large-capacity, near-term, Mars lander (dubbed ;Red Dragon;) for scientific and human precursor missions. SpaceX initially designed the Dragon capsule for flight near Earth, and Dragon has successfully flown many times to low-Earth orbit (LEO) and successfully returned the Dragon spacecraft to Earth. Here we present capsule hardware modifications that are required to enable flight to Mars and operations on the martian surface. We discuss the use of the Dragon system to support NASA Discovery class missions to Mars and focus in particular on Dragon's applications for drilling missions. We find that a Red Dragon platform is well suited for missions capable of drilling deeper on Mars (at least 2 m) than has been accomplished to date due to its ability to land in a powered controlled mode, accommodate a long drill string, and provide payload space for sample processing and analysis. We show that a Red Dragon drill lander could conduct surface missions at three possible targets including the ice-cemented ground at the Phoenix landing site (68 °N), the subsurface ice discovered near the Viking 2 (49 °N) site by fresh impact craters, and the dark sedimentary subsurface material at the Curiosity site (4.5 °S).

  2. Volume tables for red alder.

    Science.gov (United States)

    Floyd A. Johnson; R. M. Kallander; Paul G. Lauterbach

    1949-01-01

    The increasing importance of red alder as a commercial species in the Pacific Northwest has prompted the three agencies listed above to pool their tree measurement data for the construction of standard regional red alder volume tables. The tables included here were based on trees from a variety of sites and form classes. Approximately one quarter of the total number of...

  3. Skeleton decay in red cedar

    Science.gov (United States)

    Kevin T. Smith; Jessie A. Glaeser

    2013-01-01

    Eastern red cedar (Juniperus virginiana) is a common tree species throughout the eastern United States and the Great Plains. Although “cedar” is in the common name, the scientifc name shows a botanical kinship to the juniper species of the American southwest. Red cedar can survive and thrive within a broad range of soil conditions, seasonal...

  4. Argentina's nuclear red herring

    International Nuclear Information System (INIS)

    Perera, J.

    1983-01-01

    The article deals with Argentina's nuclear power programme over the last 30 years, including the country's efforts to be nuclear independent of the United States, as well as its aspirations to be a nuclear supplier to latin America. The latter policy on economic, rather than military grounds for nuclear weapons, has led to Argentina's decision to build a uranian enrichment plant. (U.K.)

  5. Romantic red: red enhances men's attraction to women.

    Science.gov (United States)

    Elliot, Andrew J; Niesta, Daniela

    2008-11-01

    In many nonhuman primates, the color red enhances males' attraction to females. In 5 experiments, the authors demonstrate a parallel effect in humans: Red, relative to other achromatic and chromatic colors, leads men to view women as more attractive and more sexually desirable. Men seem unaware of this red effect, and red does not influence women's perceptions of the attractiveness of other women, nor men's perceptions of women's overall likeability, kindness, or intelligence. The findings have clear practical implications for men and women in the mating game and, perhaps, for fashion consultants, product designers, and marketers. Furthermore, the findings document the value of extending research on signal coloration to humans and of considering color as something of a common language, both within and across species. (c) 2008 APA, all rights reserved.

  6. Red Yeast Rice: An Introduction

    Science.gov (United States)

    ... rice are used in food products in Chinese cuisine, including Peking duck. Others have been sold as ... Medicine . 2010;170(19):1722–1727. Halbert SC, French B, Gordon RY, et al. Tolerability of red ...

  7. "Congo" red: out of Africa?

    Science.gov (United States)

    Steensma, D P

    2001-02-01

    Congo red is the essential histologic stain for demonstrating the presence of amyloidosis in fixed tissues. To the best of my knowledge, nothing has been written about why the stain is named "Congo." To understand the etymology and history of the Congo red histologic stain. Primary sources were consulted extensively, including 19th-century corporate documents, newspapers, legal briefs, patents, memoirs, and scientific papers. Sources were obtained from multiple university libraries and German corporate archives. To Europeans in 1885, the word Congo evoked exotic images of far-off central Africa known as The Dark Continent. The African Congo was also a political flashpoint during the Age of Colonialism. "Congo" red was introduced in Berlin in 1885 as the first of the economically lucrative direct textile dyes. A patent on Congo red was filed by the AGFA Corporation of Berlin 3 weeks after the conclusion of the well-publicized Berlin West Africa Conference. During these important diplomatic talks, German Chancellor Otto von Bismarck presided over a discussion of free trade issues in the Congo River basin. A challenge to AGFA's Congo red patent led to a precedent-setting decision in intellectual property law. The Congo red stain was named "Congo" for marketing purposes by a German textile dyestuff company in 1885, reflecting geopolitical current events of that time.

  8. Habitability of planets around red dwarf stars.

    Science.gov (United States)

    Heath, M J; Doyle, L R; Joshi, M M; Haberle, R M

    1999-08-01

    Recent models indicate that relatively moderate climates could exist on Earth-sized planets in synchronous rotation around red dwarf stars. Investigation of the global water cycle, availability of photosynthetically active radiation in red dwarf sunlight, and the biological implications of stellar flares, which can be frequent for red dwarfs, suggests that higher plant habitability of red dwarf planets may be possible.

  9. Silvical characteristics of red maple (Acer rubrum)

    Science.gov (United States)

    Russell J. Hutnik; Harry W. Yawney

    1961-01-01

    Red maple (Acer rubrum L.) is also known as Carolina red maple, scarlet maple, soft maple, swamp maple, water maple, and white maple. Taxonomists recognize several varieties of red maple. The most common is Drummond red maple (Acer rubrum var. drummondii (Hook, & Arn.) Sarg.).

  10. Noninvasive optical inhibition with a red-shifted microbial rhodopsin

    DEFF Research Database (Denmark)

    Chuong, Amy S; Miri, Mitra L; Busskamp, Volker

    2014-01-01

    Optogenetic inhibition of the electrical activity of neurons enables the causal assessment of their contributions to brain functions. Red light penetrates deeper into tissue than other visible wavelengths. We present a red-shifted cruxhalorhodopsin, Jaws, derived from Haloarcula (Halobacterium......) salinarum (strain Shark) and engineered to result in red light-induced photocurrents three times those of earlier silencers. Jaws exhibits robust inhibition of sensory-evoked neural activity in the cortex and results in strong light responses when used in retinas of retinitis pigmentosa model mice. We also...... demonstrate that Jaws can noninvasively mediate transcranial optical inhibition of neurons deep in the brains of awake mice. The noninvasive optogenetic inhibition opened up by Jaws enables a variety of important neuroscience experiments and offers a powerful general-use chloride pump for basic and applied...

  11. Training system for the maintenance of power lines of the distribution network, ALEn3D; Sistema para la capacitacion y entrenamiento para el mantenimiento de lineas de la red de distribucion, ALEn3D

    Energy Technology Data Exchange (ETDEWEB)

    Galvan Bobadilla, Israel; Perez Ramirez, Miguel; Ayala Garcia, Andres; Munoz Roman, Jaime Javier; Rodriguez Gallegos, Eric; Salgado Martinez, Marco Antonio [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Sierra Rodriguez, Benjamin [Comision Federal de Electricidad (Mexico)

    2011-07-01

    The maintenance of power lines is a complex activity with many inherent risks. Therefore, training of personnel in this area is a priority for electric energy companies. This article presents a capacity-building system based on virtual reality developed by the Federal Electric Commission (CFE), called ALEn3D. This allows maintenance technicians to train in risk-free interactive 3D environments and to later use that knowledge with an actual installation. The work was validated by expert electricians and, therefore, the system represents a wealth of knowledge and best practices for the maintenance of distribution lines. ALEn3D was designed as a tool for self capacity-building for adults, and therefore includes usability and e-learning elements to facilitate learning and automate the students' ongoing progress. The system can be run by a personal computer, is low-cost, optimized and user friendly. It is being used in the 16 distribution divisions of the CFE. [Spanish] El mantenimiento en lineas energizadas es un actividad compleja y con muchos riesgos inherentes, por lo que la capacitacion del personal en esta area es una prioridad para las empresas de energia electrica. Este articulo presenta un sistema de capacitacion basado en realidad virtual desarrollado para la Comision Federal de Electricidad (CFE), denominado ALEn3D, el cual permite a los tecnicos de mantenimiento capacitarse en ambientes 3D interactivos libes de riesgos, para posteriormente usar esos conocimientos en una instalacion real. El trabajo fue validado por expertos electricistas, por lo tanto, el sistema es un acervo de conocimientos y mejores practicas del mantenimiento a lineas de distribucion. ALEn3D fue disenado como una herramienta de autocapacitacion para adultos, por lo que se incluyeron aspectos de usabilidad y e-learning que facilitan el aprendizaje y automatizan el seguimiento del estudiante. El sistema puede ser ejecutado en una computadora personal y es utilizado en las 16

  12. Eddy energy sources and flux in the Red Sea

    KAUST Repository

    Zhan, Peng

    2015-04-01

    In the Red Sea, eddies are reported to be one of the key features of hydrodynamics in the basin. They play a significant role in converting the energy among the large-scale circulation, the available potential energy (APE) and the eddy kinetic energy (EKE). Not only do eddies affect the horizontal circulation, deep-water formation and overturning circulation in the basin, but they also have a strong impact on the marine ecosystem by efficiently transporting heat, nutrients and carbon across the basin and by pumping the nutrient-enriched subsurface water to sustain the primary production. Previous observations and modeling work suggest that the Red Sea is rich of eddy activities. In this study, the eddy energy sources and sinks have been studied based on a high-resolution MITgcm. We have also investigated the possible mechanisms of eddy generation in the Red Sea. Eddies with high EKE are found more likely to appear in the central and northern Red Sea, with a significant seasonal variability. They are more inclined to occur during winter when they acquire their energy mainly from the conversion of APE. In winter, the central and especially the northern Red Sea are subject to important heat loss and extensive evaporation. The resultant densified upper-layer water tends to sink and release the APE through baroclinic instability, which is about one order larger than the barotropic instability contribution and is the largest source term for the EKE in the Red Sea. As a consequence, the eddy energy is confined to the upper layer but with a slope deepening from south to north. In summer, the positive surface heat flux helps maintain the stratification and impedes the gain of APE. The EKE is, therefore, much lower than that in winter despite a higher wind power input. Unlike many other seas, the wind energy is not the main source of energy to the eddies in the Red Sea.

  13. Purchasing power parity and interest parity in the laboratory

    OpenAIRE

    Fisher, Eric O'N.

    2001-01-01

    This paper analyzes purchasing power parity and uncovered interest parity in the laboratory. It finds strong evidence that purchasing power parity, covered interest parity, and uncovered interest parity hold. Subjects are endowed with an intrinsically useless (green) currency that can be used to purchase another useless (red) currency. Green goods can be bought only with green currency, and red goods can be bought only with red currency. The foreign exchange markets are organized as call mark...

  14. DAVs: Red Edge and Outbursts

    Science.gov (United States)

    Luan, Jing

    2018-04-01

    As established by ground based surveys, white dwarfs with hydrogen atmospheres pulsate as they cool across the temperature range, 12500Kred edge is a two-decade old puzzle. Recently, Kepler discovered a number of cool DAVs exhibiting sporadic outbursts separated by days, each lasting several hours, and releasing \\sim 10^{33}-10^{34} {erg}. We provide quantitative explanations for both the red edge and the outbursts. The minimal frequency for overstable modes rises abruptly near the red edge. Although high frequency overstable modes exist below the red edge, their photometric amplitudes are generally too small to be detected by ground based observations. Nevertheless, these overstable parent modes can manifest themselves through nonlinear mode couplings to damped daughter modes which generate limit cycles giving rise to photometric outbursts.

  15. Self-Oscillating Wireless Power Transfer Systems

    OpenAIRE

    Tretyakov, Sergei A.; Simovski, Constantin R.; Valagiannopoulos, Constantinos A.; Ra'di, Younes

    2017-01-01

    Conventional wireless power transfer systems consist of a microwave power generator and transmitter located at one place and a microwave power receiver located at a distance. Here we show that wireless power transfer can be realized as a single distributed microwave generator with an over-the-air feedback, so that the microwave power is generated directly at the place where the energy needs to be delivered. We demonstrate that the use of this paradigm increases efficiency and dramatically red...

  16. Red Plague Control Plan (RPCP)

    Science.gov (United States)

    Cooke, Robert W.

    2010-01-01

    SCOPE: Prescribes the minimum requirements for the control of cuprous / cupric oxide corrosion (a.k.a. Red Plague) of silver-coated copper wire, cable, and harness assemblies. PURPOSE: Targeted for applications where exposure to assembly processes, environmental conditions, and contamination may promote the development of cuprous / cupric oxide corrosion (a.k.a. Red Plague) in silver-coated copper wire, cable, and harness assemblies. Does not exclude any alternate or contractor-proprietary documents or processes that meet or exceed the baseline of requirements established by this document. Use of alternate or contractor-proprietary documents or processes shall require review and prior approval of the procuring NASA activity.

  17. Red de senderos universitarios inteligentes

    OpenAIRE

    Ibarra-Berrocal, I.J.; Romero, J.; Pérez, J.

    2017-01-01

    Introducción: El Proyecto de red de senderos universitarios inteligentes UR se inspira en tres realidades, la red de senderos europeos ya existentes y su importancia en el fomento de la actividad deportiva y los hábitos saludables, la creciente importancia de la implantación, intercambio y difusión de políticas y planes de acción en materia de sostenibilidad ambiental en el ámbito universitario europeo, y por último, el uso y desarrollo de infraestructuras y aplicaciones, cada vez más impresc...

  18. Seguridad en una red universitaria

    OpenAIRE

    Bernal España, Juan Antonio

    2014-01-01

    Las redes de comunicaciones son muy importantes para las empresas. Se solicita una red de altas prestaciones que pueda llevar muchos sistemas sobre ella (cámaras de seguridad, video, voz, datos, SCADA, wifi). Ahora también necesitamos que la red sea segura. Cuando hablamos de seguridad no solo nos referimos a evitar ataques o virus, también hablamos de cómo puede afectarnos el incendio de un centro de proceso de datos. Basándonos en la ISO 27001:2013 daremos las principales pau...

  19. Nonlinear analysis of RED - a comparative study

    International Nuclear Information System (INIS)

    Jiang Kai; Wang Xiaofan; Xi Yugeng

    2004-01-01

    Random Early Detection (RED) is an active queue management (AQM) mechanism for routers on the Internet. In this paper, performance of RED and Adaptive RED are compared from the viewpoint of nonlinear dynamics. In particular, we reveal the relationship between the performance of the network and its nonlinear dynamical behavior. We measure the maximal Lyapunov exponent and Hurst parameter of the average queue length of RED and Adaptive RED, as well as the throughput and packet loss rate of the aggregate traffic on the bottleneck link. Our simulation scenarios include FTP flows and Web flows, one-way and two-way traffic. In most situations, Adaptive RED has smaller maximal Lyapunov exponents, lower Hurst parameters, higher throughput and lower packet loss rate than that of RED. This confirms that Adaptive RED has better performance than RED

  20. Nonlinear analysis of RED - a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Kai; Wang Xiaofan E-mail: xfwang@sjtu.edu.cn; Xi Yugeng

    2004-09-01

    Random Early Detection (RED) is an active queue management (AQM) mechanism for routers on the Internet. In this paper, performance of RED and Adaptive RED are compared from the viewpoint of nonlinear dynamics. In particular, we reveal the relationship between the performance of the network and its nonlinear dynamical behavior. We measure the maximal Lyapunov exponent and Hurst parameter of the average queue length of RED and Adaptive RED, as well as the throughput and packet loss rate of the aggregate traffic on the bottleneck link. Our simulation scenarios include FTP flows and Web flows, one-way and two-way traffic. In most situations, Adaptive RED has smaller maximal Lyapunov exponents, lower Hurst parameters, higher throughput and lower packet loss rate than that of RED. This confirms that Adaptive RED has better performance than RED.

  1. Germination of red alder seed.

    Science.gov (United States)

    M.A. Radwan; D.S. DeBell

    1981-01-01

    Red alder seeds were collected from six locations throughout the natural range of the species. Each seed lot was obtained from a single tree, and the seeds were used to determine germination with and without stratification treatment. Irrespective of treatment, germination varied significantly (P

  2. Red light running camera assessment.

    Science.gov (United States)

    2011-04-01

    In the 2004-2007 period, the Mission Street SE and 25th Street SE intersection in Salem, Oregon showed relatively few crashes attributable to red light running (RLR) but, since a high number of RLR violations were observed, the intersection was ident...

  3. Red Teaming: Past and Present

    Science.gov (United States)

    2008-05-22

    cultural and ethnocentric bias, and a focus on fully exploring alternatives. The purpose of this monograph is to examine historical and...Planning and Orders Production, introduces red team principles into the army problem solving method.14 Additionally, TRADOC staffed and funded the...organization, incorporating alternative perspectives in an attempt to eliminate cultural and ethnocentric bias, and a focus on fully exploring

  4. The red-blue conundrum

    DEFF Research Database (Denmark)

    Nørtoft, Mikkel Johansen

    2017-01-01

    Plants from the Rubiaceae family (Rubia, Galium, and Asperula) are often grouped together as madder because they have been used for dyeing red since at least the Bronze Age. The English plant name madder can be traced through the Germanic language all the way back to Proto-Indo-European (PIE), as...

  5. Crossing Our Red Lines About Partner Engagement in Mexico

    Science.gov (United States)

    2013-03-01

    market prices. The Tijuana, Sinaloa, Juarez and Gulf Cartels, La Familia Michoacana/Los Caballeros Templarios and Los Zetas are loosely federated...Develop and employ soft power.  Law 5: Cultivate community support or acquiescence. Ibid., 25-32. 6 It is true that a few cartels (e.g., La Familia ...against the Iranian nuclear program: Presidents of the US… don’t have… a bunch of little red lines that determine their decisions. What they have

  6. Gravity modes as a way to distinguish between hydrogen- and helium-burning red giant stars

    DEFF Research Database (Denmark)

    Bedding, Timothy R.; Mosser, Benoit; Huber, Daniel

    2011-01-01

    Red giants are evolved stars that have exhausted the supply of hydrogen in their cores and instead burn hydrogen in a surrounding shell. Once a red giant is sufficiently evolved, the helium in the core also undergoes fusion. Outstanding issues in our understanding of red giants include...... uncertainties in the amount of mass lost at the surface before helium ignition and the amount of internal mixing from rotation and other processes. Progress is hampered by our inability to distinguish between red giants burning helium in the core and those still only burning hydrogen in a shell....... Asteroseismology offers a way forward, being a powerful tool for probing the internal structures of stars using their natural oscillation frequencies. Here we report observations of gravity-mode period spacings in red giants that permit a distinction between evolutionary stages to be made. We use high...

  7. Comportamiento de la Tecnología PLC en la Red Eléctrica

    OpenAIRE

    García Guibout, J.; García Garino, Carlos; Fusario, Rubén J.; Castro Lechtaler, Antonio; Sevilla, Guillermo

    2007-01-01

    La tecnología PLC1 - PowerLine Communications- está referida a la transmisión de datos utilizando la red eléctrica, tanto domiciliaria, como la red de distribución de baja tensión. Dependiendo del tipo de red que se utilice como soporte esta tecnología se divide en PLC indoor y outdoor. La primera se refiere a la utilización de la red domiciliaria y utiliza las frecuencias más altas de 5 MHz a 30 ó 40 MHz. La segunda, outdoor, usa la red de distribución y las frecuencias bajas de 1 MHz a 5 ó ...

  8. Thermodynamic, energy efficiency, and power density analysis of reverse electrodialysis power generation with natural salinity gradients.

    Science.gov (United States)

    Yip, Ngai Yin; Vermaas, David A; Nijmeijer, Kitty; Elimelech, Menachem

    2014-05-06

    Reverse electrodialysis (RED) can harness the Gibbs free energy of mixing when fresh river water flows into the sea for sustainable power generation. In this study, we carry out a thermodynamic and energy efficiency analysis of RED power generation, and assess the membrane power density. First, we present a reversible thermodynamic model for RED and verify that the theoretical maximum extractable work in a reversible RED process is identical to the Gibbs free energy of mixing. Work extraction in an irreversible process with maximized power density using a constant-resistance load is then examined to assess the energy conversion efficiency and power density. With equal volumes of seawater and river water, energy conversion efficiency of ∼ 33-44% can be obtained in RED, while the rest is lost through dissipation in the internal resistance of the ion-exchange membrane stack. We show that imperfections in the selectivity of typical ion exchange membranes (namely, co-ion transport, osmosis, and electro-osmosis) can detrimentally lower efficiency by up to 26%, with co-ion leakage being the dominant effect. Further inspection of the power density profile during RED revealed inherent ineffectiveness toward the end of the process. By judicious early discontinuation of the controlled mixing process, the overall power density performance can be considerably enhanced by up to 7-fold, without significant compromise to the energy efficiency. Additionally, membrane resistance was found to be an important factor in determining the power densities attainable. Lastly, the performance of an RED stack was examined for different membrane conductivities and intermembrane distances simulating high performance membranes and stack design. By thoughtful selection of the operating parameters, an efficiency of ∼ 37% and an overall gross power density of 3.5 W/m(2) represent the maximum performance that can potentially be achieved in a seawater-river water RED system with low

  9. Race, Feminine Power, and the Vietnam War in Philip Red Eagle's "Red Earth"

    Science.gov (United States)

    Andrews, Scott

    2004-01-01

    In her book "The Remasculinization of America," Susan Jeffords discusses the dynamics of how differences such as race and class are erased in filmic and literary representations of the Vietnam War. She asserts that one difference is not overcome by the battlefield: gender, a barrier that is depicted in the literature as natural and…

  10. Comparative metagenomics of the Red Sea

    KAUST Repository

    Mineta, Katsuhiko

    2016-01-01

    started monthly samplings of the metagenomes in the Red Sea under KAUST-CCF project. In collaboration with Kitasato University, we also collected the metagenome data from the ocean in Japan, which shows contrasting features to the Red Sea. Therefore

  11. Nutrient Limitation in Central Red Sea Mangroves

    KAUST Repository

    Almahasheer, Hanan; Duarte, Carlos M.; Irigoien, Xabier

    2016-01-01

    Red Sea have characteristic heights of ~2 m, suggesting nutrient limitation. We assessed the nutrient status of mangrove stands in the Central Red Sea and conducted a fertilization experiment (N, P and Fe and various combinations thereof) on 4-week

  12. Red Assembly: the work remains

    Directory of Open Access Journals (Sweden)

    Leslie Witz

    Full Text Available This issue of Kronos is dedicated to Terry Flynn, assistant curator at the Ann Bryant Art Gallery, who was instrumental in the successful installing of 'Red Assembly' there in 2015. Friend, colleague, artist and inspiration. Hamba Kahle. The work that emerged from the encounter with Red, an art installation by Simon Gush and his collaborators, in the workshop 'Red Assembly', held in East London in August 2015, is assembled here in Kronos, the journal of southern African histories based at the University of the Western Cape, and previously in parallax, the cultural studies journal based at the University of Leeds published in May 2016. What is presented there and here is not simply more work, work that follows, or even additional works. Rather, it is the work that arises as a response to a question that structured our entire project: does Red, now also installed in these two journals, have the potential to call the discourse of history into question? This article responds to this question through several pairings: theft - gift; copy - rights; time - history; kronos - chronos. Here we identify a reversal in this installation of the gift into the commodity, and another with regard to conventional historical narratives which privilege the search for sources and origins. A difference between (the historian's search for origination and (the artist's originality becomes visible in a conversation between and over the historic and the artistic that does not simply try to rescue History by means of the work of art. It is in this sense that we invite the displacements, detours, and paths made possible through Simon Gush's Red, the 'Red Assembly' workshop and the work/gift of installation and parallaxing. To gesture beyond 'histories' is the provocation to which art is neither cause nor effect. Thinking with the work of art, that is, grasping thought in the working of art, has extended the sense of history's limit and the way the limit of history is

  13. Red alder: a state of knowledge.

    Science.gov (United States)

    Robert L. Deal; Constance A. Harrington

    2006-01-01

    In March 23-25, 2005, an international symposium on red alder was held at the University of Washington Center for Urban Horticulture in Seattle, WA. The symposium was entitled "Red alder: A State of Knowledge" and brought together regional experts to critically examine the economic, ecological and social values of red alder. The primary goal of the symposium...

  14. Red and green fluorescence from oral biofilms

    NARCIS (Netherlands)

    Volgenant, C.M.C.; Hoogenkamp, M.A.; Krom, B.P.; Janus, M.M.; ten Cate, J.M.; de Soet, J.J.; Crielaard, W.; van der Veen, M.H.

    2016-01-01

    Red and green autofluorescence have been observed from dental plaque after excitation by blue light. It has been suggested that this red fluorescence is related to caries and the cariogenic potential of dental plaque. Recently, it was suggested that red fluorescence may be related to gingivitis.

  15. Effect of gamma radiation on physico-chemical characteristics of red gram (Cajanus cajan) starch

    International Nuclear Information System (INIS)

    Nene, S.P.; Vakil, U.K.; Sreenivasan, A.

    1975-01-01

    Total reducing and nonreducing sugars in red gram (Cajanus cajan) are not affected by radiation treatment (1 Mrad). Oligosaccharides, reported as flatulence factors in legumes, namely stachyose and raffinose, are slightly decreased on cooking the irradiated samples. Irradiated and cooked red gram starch is more susceptible to alpha-amylase action than the unirradiated sample. Rheological properties of red gram starch, such as gelatinization viscosity, swelling power and solubility improve on irradiation resulting in a final cooked product with better textural properties. (U.S.)

  16. Allergic reactions in red tattoos

    DEFF Research Database (Denmark)

    Hutton Carlsen, K; Køcks, M; Sepehri, M

    2016-01-01

    to be feasible for chemical analysis of red pigments in allergic reactions. Raman spectroscopy has a major potential for fingerprint screening of problematic tattoo pigments in situ in skin, ex vivo in skin biopsies and in tattoo ink stock products, thus, to eliminate unsafe ink products from markets.......AIM: The aim of this study was to assess the feasibility of Raman spectroscopy as a screening technique for chemical characterisation of tattoo pigments in pathologic reacting tattoos and tattoo ink stock products to depict unsafe pigments and metabolites of pigments. MATERIALS/METHODS: Twelve...... dermatome shave biopsies from allergic reactions in red tattoos were analysed with Raman spectroscopy (A 785-nm 300 mW diode laser). These were referenced to samples of 10 different standard tattoo ink stock products, three of these identified as the culprit inks used by the tattooist and thus by history...

  17. Red fox sightings in Rome

    Directory of Open Access Journals (Sweden)

    Bruno Cignini

    1997-12-01

    Full Text Available Abstract In this study preliminary data on the presence of Red fox in Rome (an area of 360 km² within the Rome ringroad. G.R.A. since 1980 are presented. The data were mapped on a UTM 1 sq. km. grid. Data were analysed and correlated, for each City district, with the prevalent environment (green, built-up, river-side areas and with the density of inhabitants.

  18. Resveratrol: Chemoprevention with red wine

    OpenAIRE

    Arısan, Elif Damla; Palavan-Ünsal, Narçin

    2007-01-01

    According to epidemiological studies, western diet has disadvantages because of cancer prevalence more than Mediterranean or Asia people who consume more vegetables and fruits. Resveratrol (trans-3,4,5-trihydroxystilbene) which is highly found in grapes, berries has received attention for its potential chemopreventive and antitumor effects in experimental systems. Because of high resveratrol content, researchers noted that red wine has multidimensional benefits for ...

  19. Drying hot red pepper using solar tunnel drier

    International Nuclear Information System (INIS)

    Hossain, M.A; Bala, B.K.

    2006-01-01

    A solar tunnel drier was used to dry red hot pepper under the tropical weather conditions of Bangladesh in order to investigate its performance and the quality of the drier product. The drier comprises a plastic sheet-covered flat plate collector and a drying tunnel. The drier is arranged to supply hot air to the drying tunnel using two small fans powered by a 40 watt PV module. Fresh red pepper was water blanched before drying. In each drying batch in the solar tunnel drier, 20 kg of dried red pepper with 4 to 6% moisture content (wb) was obtained from 80 kg of fresh red pepper with initial moisture content of 73 to 75% (wb) in 20 to 22 hours of drying while it took 32 to 34 hours to bring down the moisture content of similar sample to 8 to 10% (wb) in sun drying methods. The pepper dried in the solar tunnel drier was completely protected from dust, dirt, rain, insects, birds, rodents and microorganisms and it was a quality-dried product in term of colour and pungency. The solar tunnel drier is recommended for drying of pepper as well as vegetables and fruits in developing countries especially in Bangladesh

  20. Are some of the luminous high-latitude stars accretion-powered runaways?

    International Nuclear Information System (INIS)

    Leonard, P.J.T.; Hills, J.G.; Dewey, R.J.

    1992-01-01

    It is well known that (1) runaway stars can be produced via supernova explosions in close binary systems, (2) most of such runaways should possess neutron star companions, and (3) neutron stars receive randomly oriented kicks of ≅ 100 to 200 km s -1 at birth. We find that this kick sometimes has the right amplitude and direction to make the neutron star fall into the runaway. Accretion onto a neutron star is a source of energy that is roughly an order of magnitude more mass efficient than nuclear burning. Thus, runaways containing neutron stars may live much longer than would normally be expected, which would allow them to travel great distances from their birthplaces during their lifetimes. Some of the early B-type stars far from the Galactic plane and the high-latitude F and G-type supergiants may be accretion-powered runaway stars

  1. La red sobre trabajo infantil peligroso (Red Tip

    Directory of Open Access Journals (Sweden)

    Walter Varillas

    2003-01-01

    Full Text Available En el mundo, aproximadamente 351.7 millones de niños entre 5 y 17 años realizaban algún tipo de actividad económica, de ellos 170.5 millones (48.5% realizaban algún tipo de trabajo considerado peligroso. Un alto porcentaje se encuentra en la agricultura, otros en minas, manufacturas, ladrilleras, predominantemente en la economía informal. El Convenio 138 (cobre la edad mínima de admisión en el empleo de la OIT y el Convenio 182 (sobre las peores formas de trabajo infantil, definen como trabajo infantil peligroso el que puede afectar la salud, seguridad y moralidad de los menores. Estudios específicos sobre los menores muestran su susceptibilidad particular frente a los riesgos laborales, aumentando la peligrosidad para su normal desarrollo y crecimiento: "los niños no son adultos pequeños". Los profesionales de la seguridad y salud en el trabajo pueden colaborar con los profesionales y las organizaciones especializadas en el trabajo infantil, en la definición y caracterización de lo que significa el trabajo infantil peligroso. Para ello se ha conformado la Red sobre Trabajo Infantil Peligroso (Red TIP, con la finalidad de articular estos dos espacios, orientados a eliminar el trabajo infantil peligroso y rescatar al menor y devolverle la oportunidad de sonreír ahora y en el futuro.

  2. Red giants: then and now

    Science.gov (United States)

    Faulkner, John

    Fred Hoyle's work on the structure and evolution of red giants, particularly his pathbreaking contribution with Martin Schwarzschild (Hoyle and Schwarzschild 1955), is both lauded and critically assessed. In his later lectures and work with students in the early 1960s, Hoyle presented more physical ways of understanding some of the approximations used, and results obtained, in that seminal paper. Although later ideas by other investigators will be touched upon, Hoyle's viewpoint - that low-mass red giants are essentially white dwarfs with a serious mass-storage problem - is still extremely fruitful. Over the years, I have further developed his method of attack. Relatively recently, I have been able to deepen and broaden the approach, finally extending the theory to provide a unifying treatment of the structure of low-mass stars from the main sequence though both the red-giant and horizontal-branch phases of evolution. Many aspects of these stars that had remained puzzling, even mysterious, for decades have now fallen into place, and some questions have been answered that were not even posed before. With low-mass red giants as the simplest example, this recent work emphasizes that stars, in general, may have at least two distinct but very important centres: (I) a geometrical centre, and (II) a separate nuclear centre, residing in a shell outside a zero-luminosity dense core for example. This two-centre perspective leads to an explicit, analytical, asymptotic theory of low-mass red-giant structure. It enables one to appreciate that the problem of understanding why such stars become red giants is one of anticipating a remarkable yet natural structural bifurcation that occurs in them. This bifurcation occurs because of a combination of known and understandable facts just summarized namely that, following central hydrogen exhaustion, a thin nuclear-burning shell does develop outside a more-or-less dense core. In the resulting theory, both ρsh/ρolinec and

  3. Iridotomy with red krypton laser.

    Science.gov (United States)

    Yassur, Y; David, R; Rosenblatt, I; Marmour, U

    1986-01-01

    Iridotomy with red krypton laser instead of blue-green argon laser was performed on 68 eyes with various types of angle-closure glaucoma. Patent iridotomy was obtained in all the eyes, mostly in one working session. In eight eyes secondary closure by pigment needed reopening with a few applications at the iridotomy site. There were no immediate or late complications of importance, the main advantage of the technique being the avoidance of the corneal epithelial and endothelial burns which commonly occur during argon laser iridotomy, particularly when the anterior chamber is shallow. PMID:3964628

  4. Red is Romantic, but Only for Feminine Females: Sexual Dimorphism Moderates Red Effect on Sexual Attraction

    Directory of Open Access Journals (Sweden)

    Fangfang Wen

    2014-10-01

    Full Text Available Previous researchers have documented that the color red enhances one's sexual attraction to the opposite sex. The current study further examined the moderating role of sexual dimorphism in red effects. The results indicated that red enhanced men's sexual attraction to women with more feminine facial characteristics but had no effect on ratings of perceived general attractiveness. Red clothing also had a marginally significant effect on men's sexual attractiveness. In addition, regardless of sexual dimorphism cues, male participants rated women with red as warmer and more competent. The underlying mechanisms of the red effect, the limitations of the current study, and suggestions for future directions are discussed.

  5. Adsorption of procion red and congo red dyes using microalgae Spirulina sp

    Directory of Open Access Journals (Sweden)

    Risfidian Mohadi

    2017-10-01

    Full Text Available Adsorption of procion red and congo red dyes using microalgae Spirulina sp was conducted. Spirulina sp was obtained by cultivation and production in laboratory scale. Spirulina sp was used as adsorbent for adsorption of dyes. Adsorption process was studied by kinetic and thermodynamic in order to know the adsorption phenomena. The results showed that kinetically congo red is reactive than procion red on Spirulina sp. On the other hand, thermodynamically procion red was stable than congo red on Spirulina sp which was indicated by adsorption capacity, enthalpy, and entropy.

  6. Antibacterial Compounds from Red Seaweeds (Rhodophyta)

    OpenAIRE

    Noer Kasanah; Triyanto Triyanto; Drajad Sarwo Seto; Windi Amelia; Alim Isnansetyo

    2015-01-01

    Seaweeds produce great variety of metabolites benefit for human. Red seaweeds (Rhodophyta) are well known as producer of phycocolloids such agar, agarose, carragenan and great variety of secondary metabolites. This review discusses the red algal secondary metabolites with antibacterial activity. The chemical constituents of red algae are steroid, terpenoid, acetogenin and dominated by halogenated compounds mainly brominated compounds. Novel compounds with intriguing skeleton are also reported...

  7. Radiosensitivity of red flour beetle tribolium castaneum

    International Nuclear Information System (INIS)

    Sattar, A.; Khattak, S.; Hamed, M.

    1992-07-01

    In this report radiosensitivity of red beetle has been discussed. Red flour beetle is the most injurious pest causing great losses to stored grain. Radiation is one of the best tools of insect control. Different radiation doses (50 to 200 krads) were employed for different age groups from 1 to 60 days. It is concluded from these results that 200 krad radiation dose caused 100% mortality in red beetle in all age group. (A.B.)

  8. Antibacterial Compounds from Red Seaweeds (Rhodophyta

    Directory of Open Access Journals (Sweden)

    Noer Kasanah

    2015-07-01

    Full Text Available Seaweeds produce great variety of metabolites benefit for human. Red seaweeds (Rhodophyta are well known as producer of phycocolloids such agar, agarose, carragenan and great variety of secondary metabolites. This review discusses the red algal secondary metabolites with antibacterial activity. The chemical constituents of red algae are steroid, terpenoid, acetogenin and dominated by halogenated compounds mainly brominated compounds. Novel compounds with intriguing skeleton are also reported such as bromophycolides and neurymenolides. In summary, red seaweeds are potential sources for antibacterial agents and can serve as lead in synthesis of new natural medicines.

  9. Infra Red 3D Computer Mouse

    DEFF Research Database (Denmark)

    Harbo, Anders La-Cour; Stoustrup, Jakob

    2000-01-01

    The infra red 3D mouse is a three dimensional input device to a computer. It works by determining the position of an arbitrary object (like a hand) by emitting infra red signals from a number of locations and measuring the reflected intensities. To maximize stability, robustness, and use of bandw......The infra red 3D mouse is a three dimensional input device to a computer. It works by determining the position of an arbitrary object (like a hand) by emitting infra red signals from a number of locations and measuring the reflected intensities. To maximize stability, robustness, and use...

  10. Effects of red and blue LD lights on the growth of lettuce

    International Nuclear Information System (INIS)

    Mori, Y.; Takatsuji, M.; Yasuoka, T.

    2003-01-01

    In this study, Lactuca sativa L. cv. “Red Fire” was cultivated under visible laser diodes (LD) light alone, using red and blue LD for digital versatile discs (DVD). Relative growth rate, photosynthetic rate and vitamin C content were measured, and compared with those obtained using light emitting diodes (LED). When the lettuce was cultivated under LD light, the relative growth rate and net photosynthetic rate were decreased compared to those under LED light. The rates were decreased by 10% and 20% or more under red LD light and under a combination of red and blue LD lights, respectively. However, the vitamin C content was higher when grown under LD light than LED light. Considering the high output and high electrical-to-optical power conversion efficiency of LD, LD are potential light sources for plant cultivation when their prices decrease

  11. The acute stress response of red porgy, Pagrus pagrus, kept on a red or white background

    NARCIS (Netherlands)

    Salm, A.L. van der; Pavlidis, M; Flik, G.; Wendelaar Bonga, S.E.

    2005-01-01

    The skin colour of red porgy, Pagrus pagrus, can be modified by exposure to different background colours. Red and white background colours brighten the dark skin colour that develops under common culture conditions in red porgy. To assess whether skin colour is also modified by aquaculture related

  12. When red means go : non-normative effects of red under sensation seeking

    NARCIS (Netherlands)

    Mehta, R.; Demmers, J.; van Dolen, W.M.; Weinberg, C.B.

    Although previous research has identified red as the color of compliance, the current work proposes that this effect of red may not hold under high sensation-seeking propensity conditions. It is argued that the color red has the capability to induce arousal, which in turn has been shown to enhance a

  13. Control of poultry red mites

    DEFF Research Database (Denmark)

    Kilpinen, Ole; Steenberg, Tove

    2008-01-01

    The poultry red mite (PRM), Dermanyssus gallinae, is the most important ectoparasite in European egg production. The mites hide in cracks and crevices in the near vicinity of the resting places of the birds, coming out to feed mainly during the night. Under favourable conditions the population can...... grow rapidly, leading to serious problems. Large mite populations may cause anaemia or even death to the poultry, but also in lower numbers mites may be a nuisance to the birds causing decreased egg production and egg quality. Furthermore, they may have the potential of acting as reservoir......-pathogenic fungi and desiccant dust. The dust is diatomaceous earth (of natural origin), synthetic silica products or combinations of the two. The progress of the work with desiccant dusts will be reported. So far, 7 different products have been tested in the laboratory with regard to their efficacy, speed...

  14. Nitrogen depletion in field red giants

    DEFF Research Database (Denmark)

    Masseron, T.; Lagarde, N.; Miglio, A.

    2017-01-01

    , the behaviour of nitrogen data along the evolution confirms the existence of non-canonical extramixing on the red giant branch (RGB) for all low-mass stars in the field. But more surprisingly, the data indicate that nitrogen has been depleted between the RGB tip and the red clump. This may suggest that some...

  15. Mycobacterium bovis Infection of Red Fox, France.

    Science.gov (United States)

    Michelet, Lorraine; De Cruz, Krystel; Hénault, Sylvie; Tambosco, Jennifer; Richomme, Céline; Réveillaud, Édouard; Gares, Hélène; Moyen, Jean-Louis; Boschiroli, María Laura

    2018-06-01

    Mycobacterium bovis infection in wild red foxes was found in southern France, where livestock and other wildlife species are infected. Foxes frequently interact with cattle but have been underestimated as a reservoir of M. bovis. Our results suggest a possible role of the red fox in the epidemiology of bovine tuberculosis.

  16. Red blood cell alloimmunization after blood transfusion

    NARCIS (Netherlands)

    Schonewille, Henk

    2008-01-01

    Current pretransfusion policy requires the patients’ serum to be tested for the presence of irregular red blood cell antibodies. In case of an antibody, red blood cells lacking the corresponding antigen are transfused after an antiglobulin crossmatch. The aim of the studies in this thesis is

  17. Seeing red to being red: conserved genetic mechanism for red cone oil droplets and co-option for red coloration in birds and turtles.

    Science.gov (United States)

    Twyman, Hanlu; Valenzuela, Nicole; Literman, Robert; Andersson, Staffan; Mundy, Nicholas I

    2016-08-17

    Avian ketocarotenoid pigments occur in both the red retinal oil droplets that contribute to colour vision and bright red coloration used in signalling. Turtles are the only other tetrapods with red retinal oil droplets, and some also display red carotenoid-based coloration. Recently, the CYP2J19 gene was strongly implicated in ketocarotenoid synthesis in birds. Here, we investigate CYP2J19 evolution in relation to colour vision and red coloration in reptiles using genomic and expression data. We show that turtles, but not crocodiles or lepidosaurs, possess a CYP2J19 orthologue, which arose via gene duplication before turtles and archosaurs split, and which is strongly and specifically expressed in the ketocarotenoid-containing retina and red integument. We infer that CYP2J19 initially functioned in colour vision in archelosaurs and conclude that red ketocarotenoid-based coloration evolved independently in birds and turtles via gene regulatory changes of CYP2J19 Our results suggest that red oil droplets contributed to colour vision in dinosaurs and pterosaurs. © 2016 The Author(s).

  18. Improving Mineral Nutrition of Micropropagated Red Raspberry

    Science.gov (United States)

    In vitro propagation is important for fast multiplication of a wide range of nursery crops, including red raspberry. The variation in genetic background of the many red raspberry cultivars makes it difficult to successfully use one growth medium for all. Although most cultivars will grow on Murashig...

  19. Red Sea as a source for bioprospecting

    KAUST Repository

    Kodzius, Rimantas

    2015-01-01

    King-Abdullah University of Science and Technology (KAUST) is located on the shores of the Red Sea in Saudi Arabia. The Red Sea is well known for its unique environment, harboring various microbes capable of surviving in salty brines. We collected

  20. The Austrian x red pine hybrid

    Science.gov (United States)

    W. B. Critchfield

    1963-01-01

    The genetic improvement of red pine (Pinus resinosa Ait.) presents tree breeders with one of their most difficult problems. Not only is this valuable species remarkably uniform, but until 1955 it resisted all attempts to cross it with other pines. In that year red pine and Austrian pine (P. nigra var. austriaca [...

  1. Red Dirt Thinking on Aspiration and Success

    Science.gov (United States)

    Osborne, Sam; Guenther, John

    2013-01-01

    This article sets the scene for the series of five articles on "red dirt thinking". It first introduces the idea behind red dirt thinking as opposed to "blue sky thinking". Both accept that there are any number of creative and expansive solutions and possibilities to identified challenges--in this case, the challenge of…

  2. Human Red Cells With Paroxysmal Nocturnal Haemoglobinuria ...

    African Journals Online (AJOL)

    The purified cells were used as hosts for the culture of P.falciparum in vitro. Results show that GPI-linked molecules on the red cell surface are not required for the efficient entry of the parasites, and that the PNH red cells are competent to sustain the growth of P.falciparum. Nigerian Quarterly Journal of Hospital Medicine Vol ...

  3. La red sobre trabajo infantil peligroso (Red Tip The hazardous child labor network (Red Tip

    Directory of Open Access Journals (Sweden)

    Walter Varillas

    2003-01-01

    Full Text Available En el mundo, aproximadamente 351.7 millones de niños entre 5 y 17 años realizaban algún tipo de actividad económica, de ellos 170.5 millones (48.5% realizaban algún tipo de trabajo considerado peligroso. Un alto porcentaje se encuentra en la agricultura, otros en minas, manufacturas, ladrilleras, predominantemente en la economía informal. El Convenio 138 (cobre la edad mínima de admisión en el empleo de la OIT y el Convenio 182 (sobre las peores formas de trabajo infantil, definen como trabajo infantil peligroso el que puede afectar la salud, seguridad y moralidad de los menores. Estudios específicos sobre los menores muestran su susceptibilidad particular frente a los riesgos laborales, aumentando la peligrosidad para su normal desarrollo y crecimiento: "los niños no son adultos pequeños". Los profesionales de la seguridad y salud en el trabajo pueden colaborar con los profesionales y las organizaciones especializadas en el trabajo infantil, en la definición y caracterización de lo que significa el trabajo infantil peligroso. Para ello se ha conformado la Red sobre Trabajo Infantil Peligroso (Red TIP, con la finalidad de articular estos dos espacios, orientados a eliminar el trabajo infantil peligroso y rescatar al menor y devolverle la oportunidad de sonreír ahora y en el futuro.In the world, approximately 351.7 millions children between 5 and 17 years old work. Of them, 170,5 millions (48.5% work at the hazardous child labor forms. A high percentage is in agriculture, others in mines, manufactures, brick makers, predominantly in informal economy. The 138 Convention of ILO and the 182 Convention, define as hazardous child labor activities that can affect the health, safety and morality of the children. Studies on the children at work point out their particular susceptibility to some occupational risks, increasing the danger for their normal development and growth. "They are not little adults". The occupational health

  4. 21 CFR 640.10 - Red Blood Cells.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Red Blood Cells. 640.10 Section 640.10 Food and... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.10 Red Blood Cells. The proper name of this product shall be Red Blood Cells. The product is defined as red blood cells remaining...

  5. White dwarf-red dwarf binaries in the Galaxy

    NARCIS (Netherlands)

    Besselaar, E.J.M. van den

    2007-01-01

    This PhD thesis shows several studies on white dwarf - red dwarf binaries. White dwarfs are the end products of most stars and red dwarfs are normal hydrogen burning low-mass stars. White dwarf - red dwarf binaries are both blue (white dwarf) and red (red dwarf). Together with the fact that they are

  6. From red giants to planetary nebulae

    International Nuclear Information System (INIS)

    Kwok, S.

    1982-01-01

    The transition from red giants to planetary nebulae is studied by comparing the spectral characteristics of red giant envelopes and planetary nebulae. Observational and theoretical evidence both suggest that remnants of red giant envelopes may still be present in planetary nebula systems and should have significant effects on their formation. The dynamical effects of the interaction of stellar winds from central stars of planetary nebulae with the remnant red giant envelopes are evaluated and the mechanism found to be capable of producing the observed masses and momenta of planetary nebulae. The observed mass-radii relation of planetary nebulae may also be best explained by the interacting winds model. The possibility that red giant mass loss, and therefore the production of planetary nebulae, is different between Population I and II systems is also discussed

  7. Red algae and their use in papermaking.

    Science.gov (United States)

    Seo, Yung-Bum; Lee, Youn-Woo; Lee, Chun-Han; You, Hack-Chul

    2010-04-01

    Gelidialian red algae, that contain rhizoidal filaments, except the family Gelidiellaceae were processed to make bleached pulps, which can be used as raw materials for papermaking. Red algae consist of rhizoidal filaments, cortical cells usually reddish in color, and medullary cells filled with mucilaginous carbohydrates. Red algae pulp consists of mostly rhizoidal filaments. Red algae pulp of high brightness can be produced by extracting mucilaginous carbohydrates after heating the algae in an aqueous medium and subsequently treating the extracted with bleaching chemicals. In this study, we prepared paper samples from bleached pulps obtained from two red algae species (Gelidium amansii and Gelidium corneum) and compared their properties to those of bleached wood chemical pulps. Copyright 2009 Elsevier Ltd. All rights reserved.

  8. South Africa: time is ripe for independent power

    Energy Technology Data Exchange (ETDEWEB)

    Webb, C.

    2009-09-15

    Africa's biggest producer of electricity Eskom, is at a crossroad. Almost 90% of South Africa's electricity is generated by coal-fired power stations. On-off plans for nuclear power seem to be 'on' again and the regulatory red tape that has thwarted independent power producers could be cut. 3 photos.

  9. Red and Green Fluorescence from Oral Biofilms.

    Science.gov (United States)

    Volgenant, Catherine M C; Hoogenkamp, Michel A; Krom, Bastiaan P; Janus, Marleen M; Ten Cate, Jacob M; de Soet, Johannes J; Crielaard, Wim; van der Veen, Monique H

    2016-01-01

    Red and green autofluorescence have been observed from dental plaque after excitation by blue light. It has been suggested that this red fluorescence is related to caries and the cariogenic potential of dental plaque. Recently, it was suggested that red fluorescence may be related to gingivitis. Little is known about green fluorescence from biofilms. Therefore, we assessed the dynamics of red and green fluorescence in real-time during biofilm formation. In addition, the fluorescence patterns of biofilm formed from saliva of eight different donors are described under simulated gingivitis and caries conditions. Biofilm formation was analysed for 12 hours under flow conditions in a microfluidic BioFlux flow system with high performance microscopy using a camera to allow live cell imaging. For fluorescence images dedicated excitation and emission filters were used. Both green and red fluorescence were linearly related with the total biomass of the biofilms. All biofilms displayed to some extent green and red fluorescence, with higher red and green fluorescence intensities from biofilms grown in the presence of serum (gingivitis simulation) as compared to the sucrose grown biofilms (cariogenic simulation). Remarkably, cocci with long chain lengths, presumably streptococci, were observed in the biofilms. Green and red fluorescence were not found homogeneously distributed within the biofilms: highly fluorescent spots (both green and red) were visible throughout the biomass. An increase in red fluorescence from the in vitro biofilms appeared to be related to the clinical inflammatory response of the respective saliva donors, which was previously assessed during an in vivo period of performing no-oral hygiene. The BioFlux model proved to be a reliable model to assess biofilm fluorescence. With this model, a prediction can be made whether a patient will be prone to the development of gingivitis or caries.

  10. Red and Green Fluorescence from Oral Biofilms.

    Directory of Open Access Journals (Sweden)

    Catherine M C Volgenant

    Full Text Available Red and green autofluorescence have been observed from dental plaque after excitation by blue light. It has been suggested that this red fluorescence is related to caries and the cariogenic potential of dental plaque. Recently, it was suggested that red fluorescence may be related to gingivitis. Little is known about green fluorescence from biofilms. Therefore, we assessed the dynamics of red and green fluorescence in real-time during biofilm formation. In addition, the fluorescence patterns of biofilm formed from saliva of eight different donors are described under simulated gingivitis and caries conditions. Biofilm formation was analysed for 12 hours under flow conditions in a microfluidic BioFlux flow system with high performance microscopy using a camera to allow live cell imaging. For fluorescence images dedicated excitation and emission filters were used. Both green and red fluorescence were linearly related with the total biomass of the biofilms. All biofilms displayed to some extent green and red fluorescence, with higher red and green fluorescence intensities from biofilms grown in the presence of serum (gingivitis simulation as compared to the sucrose grown biofilms (cariogenic simulation. Remarkably, cocci with long chain lengths, presumably streptococci, were observed in the biofilms. Green and red fluorescence were not found homogeneously distributed within the biofilms: highly fluorescent spots (both green and red were visible throughout the biomass. An increase in red fluorescence from the in vitro biofilms appeared to be related to the clinical inflammatory response of the respective saliva donors, which was previously assessed during an in vivo period of performing no-oral hygiene. The BioFlux model proved to be a reliable model to assess biofilm fluorescence. With this model, a prediction can be made whether a patient will be prone to the development of gingivitis or caries.

  11. Effect of Plant Growth Regulator on Red Onion Cultivation from True Seed Shallot (TSS

    Directory of Open Access Journals (Sweden)

    Tri Sudaryono

    2018-01-01

    Full Text Available Red onion is one of the strategic horticultural commodities, considering this commodity is very high consumption as a daily spice and fluctuating price. Therefore is not surprising that these commodities are contributing to inflation. Efforts to meet increasing consumption needs, it is necessary to find the right strategy to increase domestic red onion production. One of the strategies considered to increase domestic red onion production is the use of botanical seed (TSS as a source of seed on shallot cultivation. There are 2 main weaknesses of red onion cultivation with TSS as a source of seeds. The two weaknesses are TSS low growing power, which is naturally only in the 50-60 % range and the number of tubers produced is less than 3 cloves per plant. In order to solve the problem, research has been done to know the effect of plant growth regulator on the growth and red onion production from TSS and also get the description of red onion farming from TSS and tuber as seed source. The research was conducted from June to November 2017 at BPP Pare, Kediri Regency, East Java. The results showed that the use of young coconut water on TSS obtained red onion plants are able to produce the number of tubers per plant more than 3 cloves. In detail as much as 22.22 % produces the number of tubers range 4-5 per plant; 56.56 % yields 5-6 bulb range; and as much as 22.22 % produces tubers > 6. As well, wet weight of tubers when harvested weighing more than 99 g per plant. If converted per hectare, TSS red onion plants treated with young coconut water can produce a range of 30 -35 tons of wet bulb. This production is doubled compared to the production of shallots grown from tubers. Based on the analysis of the farm, red onion from TSS treated with young coconut water gives a profit of Rp 224,860,000 per hectare with B/C ratio of 3.397. This profit is more than 1.75 times compared to the profit of red onion tuber farming which is only Rp 93.787.000, - with B

  12. Red Misfits in the Sloan Digital Sky Survey: properties of star-forming red galaxies

    Science.gov (United States)

    Evans, Fraser A.; Parker, Laura C.; Roberts, Ian D.

    2018-06-01

    We study Red Misfits, a population of red, star-forming galaxies in the local Universe. We classify galaxies based on inclination-corrected optical colours and specific star formation rates derived from the Sloan Digital Sky Survey Data Release 7. Although the majority of blue galaxies are star-forming and most red galaxies exhibit little to no ongoing star formation, a small but significant population of galaxies (˜11 per cent at all stellar masses) are classified as red in colour yet actively star-forming. We explore a number of properties of these galaxies and demonstrate that Red Misfits are not simply dusty or highly inclined blue cloud galaxies or quiescent red galaxies with poorly constrained star formation. The proportion of Red Misfits is nearly independent of environment, and this population exhibits both intermediate morphologies and an enhanced likelihood of hosting an active galactic nucleus. We conclude that Red Misfits are a transition population, gradually quenching on their way to the red sequence and this quenching is dominated by internal processes rather than environmentally driven processes. We discuss the connection between Red Misfits and other transition galaxy populations, namely S0s, red spirals, and green valley galaxies.

  13. Textural properties of infra red dried apple slices as affected by high ...

    African Journals Online (AJOL)

    treatment on drying rate and textural properties of the infra red dried apple slices. Ultrasound device working at a frequency of 24 kHz with a power capacity of 200 W was used for ultrasound pre-treatment. The amplitudes used for ultrasonic ...

  14. Red and Far-Red Solar-Induced Chlorophyll Fluorescence Observations in the Tropical Rain Forest of Costa Rica

    Science.gov (United States)

    Stutz, J.; Grossmann, K.; Seibt, U.; Dierick, D.; Magney, T. S.; Frankenberg, C.

    2017-12-01

    Solar-Induced Chlorophyll Fluorescence (SIF) is a powerful proxy for photosynthetic activity. SIF can be measured using remote sensing from the leaf to the global scale. However, the relationship between SIF, photosynthetic efficiencies, Gross Primary Productivity (GPP), and their response to environmental stress conditions remain poorly constrained. The impact of canopy radiative transfer and viewing geometry at the canopy scale also requires further study. In addition, there is an urgent need for the validation of space-borne SIF measurements, especially above the tropical rain forest where ground observations at the canopy scale are sparse. Here we present observations of SIF in the red and far-red wavelength range, as well various vegetation indices (NDVI, PRI, EVI), made by a novel ground-based spectrometer system, PhotoSpec, at La Selva Biological Station, Costa Rica. Measurements began in March 2017 and have continued ever since. PhotoSpec uses a narrow (0.7 degrees) field-of-view for the simultaneous co-aligned observations of all parameters at a time resolution of 30 seconds. The 2D scanning telescope unit of PhotoSpec was used for regular surveys of around 20 tree species, 2D-raster on canopies of individual trees, as well as elevation survey scans. SIF retrievals were performed using the in-filling of Fraunhofer lines, which allows the accurate observation of SIF under sunny as well as frequent cloudy conditions. The seasonal changes of SIF at La Selva, as well as the red / far-red SIF ratio, for different tree species are presented. 2D-raster scans allow an assessment of the representativeness of narrow field-of-view observations. We will also compare the PhotoSpec data with coincident satellite observations.

  15. Reaching for the red planet

    Science.gov (United States)

    David, L

    1996-05-01

    The distant shores of Mars were reached by numerous U.S. and Russian spacecraft throughout the 1960s to mid 1970s. Nearly 20 years have passed since those successful missions which orbited and landed on the Martian surface. Two Soviet probes headed for the planet in July, 1988, but later failed. In August 1993, the U.S. Mars Observer suddenly went silent just three days before it was to enter orbit around the planet and was never heard from again. In late 1996, there will be renewed activity on the launch pads with three probes departing for the red planet: 1) The U.S. Mars Global Surveyor will be launched in November on a Delta II rocket and will orbit the planet for global mapping purposes; 2) Russia's Mars '96 mission, scheduled to fly in November on a Proton launcher, consists of an orbiter, two small stations which will land on the Martian surface, and two penetrators that will plow into the terrain; and finally, 3) a U.S. Discovery-class spacecraft, the Mars Pathfinder, has a December launch date atop a Delta II booster. The mission features a lander and a microrover that will travel short distances over Martian territory. These missions usher in a new phase of Mars exploration, setting the stage for an unprecedented volley of spacecraft that will orbit around, land on, drive across, and perhaps fly at low altitudes over the planet.

  16. A red-letter day !

    CERN Multimedia

    2008-01-01

    Today is a red-letter day for the LHC and CERN as a beam of protons has travelled around the LHC ring for the very first time! The start of LHC operation marks the end of a long period in which you have given your all, and this first particle beam circulating in the accelerator now paves the way for discoveries that will open up a whole new field of knowledge. The history of the LHC began in 1984 with a debate on the possible objectives of a future accelerator, based on the state of our knowledge at that time. The CERN Council then approved the single-stage construction of the LHC in 1996, giving the go-ahead for the work that has now reached completion. For the past twelve years, physicists, engineers and technicians from CERN and its associated institutes have been engaged in constructing the three pillars of the LHC: the accelerator (including the upgrade of the existing accelerator chain), the four experiments, and the computing ...

  17. Red Shifts and Existing Speculations

    Science.gov (United States)

    Aisenberg, Sol

    2009-03-01

    There are many current flaws, mysteries, and errors in the standard model of the universe - all based upon speculative interpretation of many excellent and verified observations. The most serious cause of some errors is the speculation about the meaning of the redshifts observed in the 1930s by Hubble. He ascribed the redshifts as due to ``an apparent Doppler effect''. This led to speculation that the remote stars were receding, and the universe was expanding -- although without observational proof of the actual receding velocity of the stars. The age of the universe, based upon the Hubble constant is pure speculation because of lack of velocity demonstration. The belief in expansion, the big bang, and of inflation should be reexamined. Also, the redshift cannot always be used as a distance measure, particularly for photons from quasars containing massive black holes that can reduce photon energy through gravitational attraction. If the linear Hubble constant is extrapolated to the most remote super novae and beyond, it would eventually require that the corresponding photon energy go to zero or become negative -- according to Hubble linear relationship. This should require a reexamination of the meaning of the red shift and the speculative consequences and give a model with fewer mysteries.

  18. Red Blood Cell Storage Lesion

    Directory of Open Access Journals (Sweden)

    Daryl J. Kor

    2009-10-01

    Full Text Available The past two decades have witnessed increased scrutiny regarding efficacy and risk of the once unquestioned therapy of red blood cell (RBC transfusion. Simultaneously, a variety of changes have been identified within the RBC and storage media during RBC preservation that are correlated with reduced tissue oxygenation and transfusion-associated adverse effects. These alterations are collectively termed the storage lesion and include extensive biochemical, biomechanical, and immunologic changes involving cells of diverse origin. Time-dependent falls is 2,3-diphosphoglycerate, intracellular RBC adenosine triphosphate, and nitric oxide have been shown to impact RBC deformability and delivery of oxygen to the end-organ. The accumulation of biologic response modifiers such as soluble CD40 ligand (sCD40L, lysophosphatidylcholine (lyso-PC, and Regulated on Activation, Normal T-cell Expressed and Secreted (RANTES have been associated with altered recipient immune function as well. This review will address the alterations occurring within the RBC and storage media during RBC preservation and will address the potential clinical consequence thereof.

  19. Decadal Stability of Red Sea Mangroves

    KAUST Repository

    Almahasheer, Hanan; Aljowair, Abdulaziz; Duarte, Carlos M.; Irigoien, Xabier

    2015-01-01

    Across the Earth, mangroves play an important role in coastal protection, both as nurseries and carbon sinks. However, due to various human and environmental impacts, the coverage of mangroves is declining on a global scale. The Red Sea is in the northern-most area of the distribution range of mangroves. Little is known about the surface covered by mangroves at this northern limit or about the changes experienced by Red Sea mangroves. We sought to study changes in the coverage of Red Sea mangroves by using multi-temporal Landsat data (1972, 2000 and 2013). Interestingly, our results show that there has been no decline in mangrove stands in the Red Sea but rather a slight increase. The area covered by mangroves is about 69 Km2 along the African shore and 51 Km2 along the Arabian Peninsula shore. From 1972 to 2013, the area covered by mangroves increased by about 0.29% y-1. We conclude that the trend exhibited by Red Sea mangroves departs from the general global decline of mangroves. Along the Red Sea, mangroves expanded by 12% over the 41 years from 1972 to 2013. Losses to Red Sea mangroves, mostly due to coastal development, have been compensated by afforestation projects.

  20. Uptake of carnitine by red blood cells

    International Nuclear Information System (INIS)

    Campa, M.; Borum, P.

    1986-01-01

    A significant amount of blood carnitine (70% of cord blood and 40% of blood from healthy adults) is partitioned into the red blood cell compartment of whole blood. Data indicate that the plasma compartment and the red blood cell compartment of whole blood represent different metabolic pools of carnitine. There are no data to indicate that red blood cells synthesize carnitine, but our understanding of the uptake of carnitine by red blood cells is negligible. Red blood cells were obtained from healthy adults, washed twice with normal saline, and used for uptake experiments. When the cells were incubated at 37 0 C in the presence of 14 C-carnitine, radioactivity was found both in the soluble cytosolic and membrane fractions of the cells following lysis. The uptake was dependent upon the time of incubation, temperature of incubation, and carnitine concentration in the incubation medium. Washed red blood cell membranes incubated with 14 C-carnitine showed specific binding of radioactivity. These data are consistent with the hypothesis that red blood cells have an uptake mechanism for L-carnitine

  1. Decadal Stability of Red Sea Mangroves

    KAUST Repository

    Almahasheer, Hanan

    2015-12-15

    Across the Earth, mangroves play an important role in coastal protection, both as nurseries and carbon sinks. However, due to various human and environmental impacts, the coverage of mangroves is declining on a global scale. The Red Sea is in the northern-most area of the distribution range of mangroves. Little is known about the surface covered by mangroves at this northern limit or about the changes experienced by Red Sea mangroves. We sought to study changes in the coverage of Red Sea mangroves by using multi-temporal Landsat data (1972, 2000 and 2013). Interestingly, our results show that there has been no decline in mangrove stands in the Red Sea but rather a slight increase. The area covered by mangroves is about 69 Km2 along the African shore and 51 Km2 along the Arabian Peninsula shore. From 1972 to 2013, the area covered by mangroves increased by about 0.29% y-1. We conclude that the trend exhibited by Red Sea mangroves departs from the general global decline of mangroves. Along the Red Sea, mangroves expanded by 12% over the 41 years from 1972 to 2013. Losses to Red Sea mangroves, mostly due to coastal development, have been compensated by afforestation projects.

  2. Surface effects on the red giant branch

    Science.gov (United States)

    Ball, W. H.; Themeßl, N.; Hekker, S.

    2018-05-01

    Individual mode frequencies have been detected in thousands of individual solar-like oscillators on the red giant branch (RGB). Fitting stellar models to these mode frequencies, however, is more difficult than in main-sequence stars. This is partly because of the uncertain magnitude of the surface effect: the systematic difference between observed and modelled frequencies caused by poor modelling of the near-surface layers. We aim to study the magnitude of the surface effect in RGB stars. Surface effect corrections used for main-sequence targets are potentially large enough to put the non-radial mixed modes in RGB stars out of order, which is unphysical. Unless this can be circumvented, model-fitting of evolved RGB stars is restricted to the radial modes, which reduces the number of available modes. Here, we present a method to suppress gravity modes (g-modes) in the cores of our stellar models, so that they have only pure pressure modes (p-modes). We show that the method gives unbiased results and apply it to three RGB solar-like oscillators in double-lined eclipsing binaries: KIC 8410637, KIC 9540226 and KIC 5640750. In all three stars, the surface effect decreases the model frequencies consistently by about 0.1-0.3 μHz at the frequency of maximum oscillation power νmax, which agrees with existing predictions from three-dimensional radiation hydrodynamics simulations. Though our method in essence discards information about the stellar cores, it provides a useful step forward in understanding the surface effect in RGB stars.

  3. Single frequency Nd:YLF and Nd:YVO4 laser in the red emission

    International Nuclear Information System (INIS)

    Camargo, Fabiola de Almeida

    2010-01-01

    All solid-state continuous-wave (cw) narrow emission linewidth and tunable red lasers are convenient alternative sources to bulky and expensive dye-lasers for high precision laser spectroscopy. Single-frequency operation of diode-pumped Nd:YLiF 4 and Nd:YVO 4 cw ring lasers were investigated in the 1.32 - 1.34μm range, together with their intracavity second-harmonic generation (SHG) to the red spectral range (0.65 - 0.67μm) using either BiB 3 O 6 (BiBO) or periodically-poled KTiOPO 4 (ppKTP) crystals. We report on such a single-end diode-pumped Nd:YVO 4 unidirectional red ring laser containing a type-I cut BiBO nonlinear crystal, yielding a record of 680 mW of single-longitudinal mode (SLM) red output power at 671.1nm without any intra-cavity etalon. For smooth SLM wavelength tuning over the full gain bandwidth (∼4 nm), a partially-coated (R = 40%) 100μm-thin etalon was found necessary, reducing the maximum SLM power (at 671.15 nm) to 380 mW. At 1342.5nm and with a T = 2% transmission output coupler, the laser provided an optimal 1.5W of single-frequency power. We demonstrate also optimal intracavity SHG of a Nd:YLF ring laser in the π- polarization (λ = 1321.5nm) using a ppKTP. The laser yielded 1.4 W of single frequency red power at 660.5 nm, as much as the maximum fundamental power that can be extracted from the resonator using an optimal output coupler. With a partially coated (R = 25%) thin etalon, the laser was tunable over Δλ∼ 1.6nm. (author)

  4. RED ONE kuvaajan työkaluna

    OpenAIRE

    Käki, Ossi

    2010-01-01

    Opinnäytetyöni projektiosa, 30-minuuttinen lyhytelokuva Huomisen Muisto – Memory of Tomorrow kuvattiin RED ONE -kameralla vuosina 2008-2009. Opinnäytetyöni kirjallinen osuus tutkii miten RED ONE soveltuu kuvaajan työvälineeksi lyhytelokuvassa. Huomisen Muisto oli ensimmäinen Tampereen ammattikorkeakoulussa RED ONE:lla kuvattu elokuva ja koko tekninen workflow piti kehittää lähes nollasta. Paljon kuvan digitaalista jälkikäsittelyä sisältävänä science fiction -elokuvana Huomisen Muisto asetti i...

  5. Psychology: red enhances human performance in contests.

    Science.gov (United States)

    Hill, Russell A; Barton, Robert A

    2005-05-19

    Red coloration is a sexually selected, testosterone-dependent signal of male quality in a variety of animals, and in some non-human species a male's dominance can be experimentally increased by attaching artificial red stimuli. Here we show that a similar effect can influence the outcome of physical contests in humans--across a range of sports, we find that wearing red is consistently associated with a higher probability of winning. These results indicate not only that sexual selection may have influenced the evolution of human response to colours, but also that the colour of sportswear needs to be taken into account to ensure a level playing field in sport.

  6. Pragmatic power

    CERN Document Server

    Eccles, William

    2008-01-01

    Pragmatic Power is focused on just three aspects of the AC electrical power system that supplies and moves the vast majority of electrical energy nearly everywhere in the world: three-phase power systems, transformers, and induction motors. The reader needs to have had an introduction to electrical circuits and AC power, although the text begins with a review of the basics of AC power. Balanced three-phase systems are studied by developing their single-phase equivalents. The study includes a look at how the cost of ""power"" is affected by reactive power and power factor. Transformers are cons

  7. Synthetic biology as red herring.

    Science.gov (United States)

    Preston, Beth

    2013-12-01

    It has become commonplace to say that with the advent of technologies like synthetic biology the line between artifacts and living organisms, policed by metaphysicians since antiquity, is beginning to blur. But that line began to blur 10,000 years ago when plants and animals were first domesticated; and has been thoroughly blurred at least since agriculture became the dominant human subsistence pattern many millennia ago. Synthetic biology is ultimately only a late and unexceptional offshoot of this prehistoric development. From this perspective, then, synthetic biology is a red herring, distracting us from more thorough philosophical consideration of the most truly revolutionary human practice-agriculture. In the first section of this paper I will make this case with regard to ontology, arguing that synthetic biology crosses no ontological lines that were not crossed already in the Neolithic. In the second section I will construct a parallel case with regard to cognition, arguing that synthetic biology as biological engineering represents no cognitive advance over what was required for domestication and the new agricultural subsistence pattern it grounds. In the final section I will make the case with regard to human existence, arguing that synthetic biology, even if wildly successful, is not in a position to cause significant existential change in what it is to be human over and above the massive existential change caused by the transition to agriculture. I conclude that a longer historical perspective casts new light on some important issues in philosophy of technology and environmental philosophy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. sample data Red River_2011-2013

    Data.gov (United States)

    U.S. Environmental Protection Agency — OK Fish Kill data from Red River 2011-2013. This dataset is associated with the following publication: Jones-Lepp, T., V. Taguchi, W. Sovocool, D. Betowski, P....

  9. Raoul Kurvitz esitleb : "Armastusest" & "RED" / Heie Treier

    Index Scriptorium Estoniae

    Treier, Heie, 1963-

    2000-01-01

    Näitus "Armastusest" Vaal-galeriis, näituse avamine toimus kunstniku performance'iga. Sõnumina mainitakse Raoul Kurvitza kuraatoriprojekti "RED" Mustpeade Maja valges saalis, loetletud eksponeeritud kunstnikud

  10. Li'l Red Schoolhouse workshops

    Science.gov (United States)

    1993-01-01

    Education specialists at Stennis conduct staff development workshops for elementary and secondary teachers of math, science and technology and other subjects as well as specialized workshops conducted in the NASA Li'l Red Schoolhouse.

  11. Red in the Face: Understanding Rosacea

    Science.gov (United States)

    ... causing them to lose work or to have low self-esteem,” says Dr. Richard Gallo, a skin expert at the University of California, San Diego. “Many psychological problems are the consequence of having this red, puffy ...

  12. Doppler interpretation of quasar red shifts.

    Science.gov (United States)

    Zapolsky, H S

    1966-08-05

    The hypothesis that the quasistellar sources (quasars) are local objects moving with velocities close to the speed of light is examined. Provided there is no observational cutoff on apparent bolometric magnitude for the quasars, the transverse Doppler effect leads to the expectation of fewer blue shifts than red shifts for an isotropic distribution of velocities. Such a distribution also yields a function N(z), the number of objects with red shift less than z which is not inconsistent with the present data. On the basis of two extreme assumptions concerning the origin of such rapidly moving sources, we computed curves of red shift plotted against magnitude. In particular, the curve obtained on the assumption that the quasars originated from an explosion in or nearby our own galaxy is in as good agreement with the observations as the curve of cosmological red shift plotted against magnitude.

  13. NOAA NCCOS: New England Red Tide Research

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Alexandrium blooms are one of several algal bloom types often called "red tides," but more correctly referred to as Harmful Algal Blooms (HABs). Alexandrium produces...

  14. Avoiding Anemia: Boost Your Red Blood Cells

    Science.gov (United States)

    ... Issues Subscribe January 2014 Print this issue Avoiding Anemia Boost Your Red Blood Cells En español Send ... Disease When Blood Cells Bend Wise Choices Preventing Anemia To prevent or treat iron-deficiency anemia: Eat ...

  15. Comparative metagenomics of the Red Sea

    KAUST Repository

    Mineta, Katsuhiko

    2016-01-26

    Metagenome produces a tremendous amount of data that comes from the organisms living in the environments. This big data enables us to examine not only microbial genes but also the community structure, interaction and adaptation mechanisms at the specific location and condition. The Red Sea has several unique characteristics such as high salinity, high temperature and low nutrition. These features must contribute to form the unique microbial community during the evolutionary process. Since 2014, we started monthly samplings of the metagenomes in the Red Sea under KAUST-CCF project. In collaboration with Kitasato University, we also collected the metagenome data from the ocean in Japan, which shows contrasting features to the Red Sea. Therefore, the comparative metagenomics of those data provides a comprehensive view of the Red Sea microbes, leading to identify key microbes, genes and networks related to those environmental differences.

  16. Dipeptides from the red alga Acanthopora spicifera

    Digital Repository Service at National Institute of Oceanography (India)

    Wahidullah, S.; De; Kamat, S.Y.

    An investigation of red alga Acanthophora spicifera afforded the known peptide, aurantiamide acetate and a new diastereoisomer of this dipeptide (dia-aurantiamide acetate). This is a first report of aurantiamide acetate from a marine source...

  17. Metagenomic studies of the Red Sea.

    Science.gov (United States)

    Behzad, Hayedeh; Ibarra, Martin Augusto; Mineta, Katsuhiko; Gojobori, Takashi

    2016-02-01

    Metagenomics has significantly advanced the field of marine microbial ecology, revealing the vast diversity of previously unknown microbial life forms in different marine niches. The tremendous amount of data generated has enabled identification of a large number of microbial genes (metagenomes), their community interactions, adaptation mechanisms, and their potential applications in pharmaceutical and biotechnology-based industries. Comparative metagenomics reveals that microbial diversity is a function of the local environment, meaning that unique or unusual environments typically harbor novel microbial species with unique genes and metabolic pathways. The Red Sea has an abundance of unique characteristics; however, its microbiota is one of the least studied among marine environments. The Red Sea harbors approximately 25 hot anoxic brine pools, plus a vibrant coral reef ecosystem. Physiochemical studies describe the Red Sea as an oligotrophic environment that contains one of the warmest and saltiest waters in the world with year-round high UV radiations. These characteristics are believed to have shaped the evolution of microbial communities in the Red Sea. Over-representation of genes involved in DNA repair, high-intensity light responses, and osmoregulation were found in the Red Sea metagenomic databases suggesting acquisition of specific environmental adaptation by the Red Sea microbiota. The Red Sea brine pools harbor a diverse range of halophilic and thermophilic bacterial and archaeal communities, which are potential sources of enzymes for pharmaceutical and biotechnology-based application. Understanding the mechanisms of these adaptations and their function within the larger ecosystem could also prove useful in light of predicted global warming scenarios where global ocean temperatures are expected to rise by 1-3°C in the next few decades. In this review, we provide an overview of the published metagenomic studies that were conducted in the Red Sea, and

  18. Photometry of Southern Hemisphere red dwarf stars

    Science.gov (United States)

    Weistrop, D.

    1980-01-01

    Results are presented for a photometric investigation of a spectroscopically selected sample of red dwarf stars in the Southern Hemisphere. Absolute magnitudes and distances for the stars are estimated from broadband red colors. Three stars which may be subluminous are identified, as are several stars which may be within 25 pc. The tangential velocity and velocity dispersion of the sample are similar to values found in other studies of nearby late-type stars.

  19. Red Wine, Resveratrol and Atrial Fibrillation

    OpenAIRE

    Stephan, Laura Siga; Almeida, Eduardo Dytz; Markoski, Melissa Medeiros; Garavaglia, Juliano; Marcadenti, Aline

    2017-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as a...

  20. Causes of Red Eye-Uveitis

    OpenAIRE

    Selçuk Sızmaz

    2012-01-01

    Uveitis, being an important cause of ocular morbidity, must be taken into consideration in the differential diagnosis and the management of patients with red eye. Uveitis entities can demonstrate variable clinical features. Patients presenting with uveitis must undergo careful systemic evaluation for exact diagnosis and treatment. Studies for standardization of uveitis with variable clinical pictures are emerging. Acute anterior uveitis and panuveitis can cause red eye. The purpose o...

  1. Clinical implications of The Red Book.

    Science.gov (United States)

    Culliford, Penny

    2012-09-01

    This presentation stresses the uniqueness of both the therapist's and patient's personal experience in clinical work and relates this to the significance of The Red Book as Jung's personal odyssey and for me personally as an analyst. I consider The Red Book's enduring relevance alongside recent psychological theories, neuroscience and early mystical writings, and conclude with a clinical vignette of a patient's response to a piece of choral music and subsequent use of active imagination. © 2012, The Society of Analytical Psychology.

  2. Red Teaming of Advanced Information Assurance Concepts

    International Nuclear Information System (INIS)

    DUGGAN, RUTH A.; WOOD, BRADLEY

    1999-01-01

    Red Teaming is an advanced form of assessment that can be used to identify weaknesses in a variety of cyber systems. it is especially beneficial when the target system is still in development when designers can readily affect improvements. This paper discusses the red team analysis process and the author's experiences applying this process to five selected Information Technology Office (ITO) projects. Some detail of the overall methodology, summary results from the five projects, and lessons learned are contained within this paper

  3. The Red Book through the ages.

    Science.gov (United States)

    Pickering, Larry K; Peter, Georges; Shulman, Stanford T

    2013-11-01

    The first edition of the Red Book was published in 1938. Since then, there have been numerous advances in the fields of infectious diseases and public health that have decreased morbidity and mortality of infants, children, and adolescents. Over the years, emerging pathogens and disease complexes have been described, sophisticated diagnostic techniques developed, advances in antimicrobial therapy have occurred, and immunizations have been implemented to prevent previously deadly diseases. Of the 18 diseases or organisms in the 1938 edition, 13 are now vaccine-preventable. Since inception of the Red Book, the aims of the editors have been to keep pace with these innovations and to continue to inform the medical community. These goals have made the Red Book a fundamental resource for pediatricians and other health care professionals in terms of guiding diagnosis, therapy, and prevention of infectious diseases. The list of 18 diseases or organisms originally described in the 1938 Red Book has expanded to include over 160 diseases or organisms in the 2012 edition. The pace of biomedical discovery, as well as the amount of information available and the number of methods for its delivery, will continue to accelerate in the future. Integration of information into future editions of the Red Book will ensure that practitioners continue to rely on the Red Book in its various electronic formats for clinical guidance and support.

  4. Power corrupts

    International Nuclear Information System (INIS)

    Bacon, H.; Valentine, J.

    1981-01-01

    The subject is covered in chapters, entitled: radiation (hazards associated with nuclear power production); wastes (radioactive wastes); accidents (actual and postulated, resulting in the release of radiation); the FBR and the plutonium cycle; costs (economics of nuclear power); spent fuel transport; civil liberties; doing without nuclear power (UK power demand; low energy strategy; energy policy; government policies; alternative energy sources). (U.K.)

  5. A Review of Prevention, Diagnosis and Treatment of Relative Energy Deficiency in Sport (RED-S) in Artistic (Synchronized) Swimming.

    Science.gov (United States)

    Robertson, Sherry; Mountjoy, Margo

    2018-05-03

    The syndrome Relative Energy Deficiency in Sport (RED-S) is a clinical entity characterized by low energy availability (LEA), which can negatively affect the health and performance of both male and female athletes. The underlying mechanism of RED-S is an inadequacy of dietary energy to support optimal health and performance. This syndrome refers to impaired physiological function including metabolic rate, menstrual function, bone health, immunity, protein synthesis, and cardiovascular health, with psychological consequences which can either precede (through restrictive dietary habits) or result from RED-S. The term RED-S extends beyond the condition termed the "Female Athlete Triad". Formerly known as synchronized swimming, artistic swimming is an Olympic sport requiring a high level of fitness as well as technical skill and artistry. The risk of RED-S is high in artistic swimming as it is an aesthetic, judged sport with an emphasis on a lean physique. RED-S is of significant concern in the sport of artistic swimming because of the potential negative effects on physical and mental health as well as consequences on athletic performance. This paper reviews health and performance consequences associated with LEA resulting in RED-S in artistic swimming. Medical and nutritional considerations specific to artistic swimming are reviewed and methods to help detect and manage RED-S are discussed. Prevention and management of RED-S in this athlete population should be a priority for coaches and the sport medicine professionals working with artistic swimming athletes should utilize the RED-S CAT, a Clinical Assessment Tool for screening and managing RED-S.

  6. 27 CFR 9.190 - Red Hill Douglas County, Oregon.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Red Hill Douglas County... Areas § 9.190 Red Hill Douglas County, Oregon. (a) Name. The name of the viticultural area described in this section is “Red Hill Douglas County, Oregon”. For purposes of part 4 of this chapter, “Red Hill...

  7. What makes red quasars red?. Observational evidence for dust extinction from line ratio analysis

    Science.gov (United States)

    Kim, Dohyeong; Im, Myungshin

    2018-02-01

    Red quasars are very red in the optical through near-infrared (NIR) wavelengths, which is possibly due to dust extinction in their host galaxies as expected in a scenario in which red quasars are an intermediate population between merger-driven star-forming galaxies and unobscured type 1 quasars. However, alternative mechanisms also exist to explain their red colors: (i) an intrinsically red continuum; (ii) an unusual high covering factor of the hot dust component, that is, CFHD = LHD/Lbol, where the LHD is the luminosity from the hot dust component and the Lbol is the bolometric luminosity; and (iii) a moderate viewing angle. In order to investigate why red quasars are red, we studied optical and NIR spectra of 20 red quasars at z 0.3 and 0.7, where the usage of the NIR spectra allowed us to look into red quasar properties in ways that are little affected by dust extinction. The Paschen to Balmer line ratios were derived for 13 red quasars and the values were found to be 10 times higher than unobscured type 1 quasars, suggesting a heavy dust extinction with AV > 2.5 mag. Furthermore, the Paschen to Balmer line ratios of red quasars are difficult to explain with plausible physical conditions without adopting the concept of the dust extinction. The CFHD of red quasars are similar to, or marginally higher than, those of unobscured type 1 quasars. The Eddington ratios, computed for 19 out of 20 red quasars, are higher than those of unobscured type 1 quasars (by factors of 3-5), and hence the moderate viewing angle scenario is disfavored. Consequently, these results strongly suggest the dust extinction that is connected to an enhanced nuclear activity as the origin of the red color of red quasars, which is consistent with the merger-driven quasar evolution scenario. Full Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/610/A31

  8. The Red Sea Modeling and Forecasting System

    KAUST Repository

    Hoteit, Ibrahim

    2015-04-01

    Despite its importance for a variety of socio-economical and political reasons and the presence of extensive coral reef gardens along its shores, the Red Sea remains one of the most under-studied large marine physical and biological systems in the global ocean. This contribution will present our efforts to build advanced modeling and forecasting capabilities for the Red Sea, which is part of the newly established Saudi ARAMCO Marine Environmental Research Center at KAUST (SAMERCK). Our Red Sea modeling system compromises both regional and nested costal MIT general circulation models (MITgcm) with resolutions varying between 8 km and 250 m to simulate the general circulation and mesoscale dynamics at various spatial scales, a 10-km resolution Weather Research Forecasting (WRF) model to simulate the atmospheric conditions, a 4-km resolution European Regional Seas Ecosystem Model (ERSEM) to simulate the Red Sea ecosystem, and a 1-km resolution WAVEWATCH-III model to simulate the wind driven surface waves conditions. We have also implemented an oil spill model, and a probabilistic dispersion and larval connectivity modeling system (CMS) based on a stochastic Lagrangian framework and incorporating biological attributes. We are using the models outputs together with available observational data to study all aspects of the Red Sea circulations. Advanced monitoring capabilities are being deployed in the Red Sea as part of the SAMERCK, comprising multiple gliders equipped with hydrographical and biological sensors, high frequency (HF) surface current/wave mapping, buoys/ moorings, etc, complementing the available satellite ocean and atmospheric observations and Automatic Weather Stations (AWS). The Red Sea models have also been equipped with advanced data assimilation capabilities. Fully parallel ensemble-based Kalman filtering (EnKF) algorithms have been implemented with the MITgcm and ERSEM for assimilating all available multivariate satellite and in-situ data sets. We

  9. The Red Sea Modeling and Forecasting System

    KAUST Repository

    Hoteit, Ibrahim; Gopalakrishnan, Ganesh; Latif, Hatem; Toye, Habib; Zhan, Peng; Kartadikaria, Aditya R.; Viswanadhapalli, Yesubabu; Yao, Fengchao; Triantafyllou, George; Langodan, Sabique; Cavaleri, Luigi; Guo, Daquan; Johns, Burt

    2015-01-01

    Despite its importance for a variety of socio-economical and political reasons and the presence of extensive coral reef gardens along its shores, the Red Sea remains one of the most under-studied large marine physical and biological systems in the global ocean. This contribution will present our efforts to build advanced modeling and forecasting capabilities for the Red Sea, which is part of the newly established Saudi ARAMCO Marine Environmental Research Center at KAUST (SAMERCK). Our Red Sea modeling system compromises both regional and nested costal MIT general circulation models (MITgcm) with resolutions varying between 8 km and 250 m to simulate the general circulation and mesoscale dynamics at various spatial scales, a 10-km resolution Weather Research Forecasting (WRF) model to simulate the atmospheric conditions, a 4-km resolution European Regional Seas Ecosystem Model (ERSEM) to simulate the Red Sea ecosystem, and a 1-km resolution WAVEWATCH-III model to simulate the wind driven surface waves conditions. We have also implemented an oil spill model, and a probabilistic dispersion and larval connectivity modeling system (CMS) based on a stochastic Lagrangian framework and incorporating biological attributes. We are using the models outputs together with available observational data to study all aspects of the Red Sea circulations. Advanced monitoring capabilities are being deployed in the Red Sea as part of the SAMERCK, comprising multiple gliders equipped with hydrographical and biological sensors, high frequency (HF) surface current/wave mapping, buoys/ moorings, etc, complementing the available satellite ocean and atmospheric observations and Automatic Weather Stations (AWS). The Red Sea models have also been equipped with advanced data assimilation capabilities. Fully parallel ensemble-based Kalman filtering (EnKF) algorithms have been implemented with the MITgcm and ERSEM for assimilating all available multivariate satellite and in-situ data sets. We

  10. Amplitudes of solar-like oscillations in red giants: Departures from the quasi-adiabatic approximation

    Directory of Open Access Journals (Sweden)

    Barban C.

    2013-03-01

    Full Text Available CoRoT and Kepler measurements reveal us that the amplitudes of solar-like oscillations detected in red giant stars scale from stars to stars in a characteristic way. This observed scaling relation is not yet fully understood but constitutes potentially a powerful diagnostic about mode physics. Quasi-adiabatic theoretical scaling relations in terms of mode amplitudes result in systematic and large differences with the measurements performed for red giant stars. The use of a non-adiabatic intensity-velocity relation derived from a non-adiabatic pulsation code significantly reduces the discrepancy with the CoRoT measurements. The origin of the remaining difference is still unknown. Departure from adiabatic eigenfunction is a very likely explanation that is investigated in the present work using a 3D hydrodynamical model of the surface layers of a representative red giant star.

  11. Catalytic hydroliquefaction of biomass with red mud and CoO-MoO sub 3 catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Klopries, B.; Hodek, W.; Bandermann, F. (Universitaet-Gesamthochschule Essen, Essen (Germany, F.R.). Inst. fuer Technische Chemie)

    1990-04-01

    Rye straw was completely hydroliquefied, using red mud or CoO-MoO{sub 3} as the catalyst. Red mud catalyst exhibited a satisfactory activity only in the presence of sulphur at {approx} 673 K. Depending on reaction conditions, different amounts of gaseous and liquid products were formed. Their product distributions were comparable to those obtained in hydroliquefaction of cellulose and lignin. All results could be described by a model which assumed that: pyrolysis precedes hydrogenation of pyrolysis products; CO and CO{sub 2} are products of pyrolysis reaction; and hydrogen is consumed mainly in hydrodeoxygenation reactions. Therefore, from a practical point of view, red mud, which is known as a coal liquefaction catalyst, can also be recommended as a cheap and powerful catalyst in the hydroliquefaction of biomass. 29 refs., 6 figs., 11 tabs.

  12. 7X performance results - final report : ASCI Red vs Red Storm.

    Energy Technology Data Exchange (ETDEWEB)

    Dinge, Dennis C. (Cray Inc., Albuquerque, NM); Davis, Michael E. (Cray Inc., Albuquerque, NM); Haskell, Karen H.; Ballance, Robert A.; Gardiner, Thomas Anthony; Stevenson, Joel O.; Noe, John P.

    2011-04-01

    The goal of the 7X performance testing was to assure Sandia National Laboratories, Cray Inc., and the Department of Energy that Red Storm would achieve its performance requirements which were defined as a comparison between ASCI Red and Red Storm. Our approach was to identify one or more problems for each application in the 7X suite, run those problems at multiple processor sizes in the capability computing range, and compare the results between ASCI Red and Red Storm. The first part of this report describes the two computer systems, the applications in the 7X suite, the test problems, and the results of the performance tests on ASCI Red and Red Storm. During the course of the testing on Red Storm, we had the opportunity to run the test problems in both single-core mode and dual-core mode and the second part of this report describes those results. Finally, we reflect on lessons learned in undertaking a major head-to-head benchmark comparison.

  13. Constraining the red shifts of TeV BL Lac objects

    Science.gov (United States)

    Qin, Longhua; Wang, Jiancheng; Yan, Dahai; Yang, Chuyuan; Yuan, Zunli; Zhou, Ming

    2018-01-01

    We present a model-dependent method to estimate the red shifts of three TeV BL Lac objects (BL Lacs) through fitting their (quasi-)simultaneous multi-waveband spectral energy distributions (SEDs) with a one-zone leptonic synchrotron self-Compton model. Considering the impact of electron energy distributions (EEDs) on the results, we use three types of EEDs to fit the SEDs: a power-law EED with exponential cut-off (PLC), a log-parabola (PLLP) EED and the broken power-law (BPL) EED. We also use a parameter α to describe the uncertainties of the extragalactic background light models, as in Abdo et al. We then use a Markov chain Monte Carlo method to explore the multi-dimensional parameter space and obtain the uncertainties of the model parameters based on the observational data. We apply our method to obtain the red shifts of three TeV BL Lac objects in the marginalized 68 per cent confidence, and find that the PLC EED does not fit the SEDs. For 3C66A, the red shift is 0.14-0.31 and 0.16-0.32 in the BPL and PLLP EEDs. For PKS1424+240, the red shift is 0.55-0.68 and 0.55-0.67 in the BPL and PLLP EEDs. For PG1553+113, the red shift is 0.22-0.48 and 0.22-0.39 in the BPL and PLLP EEDs. We also estimate the red shift of PKS1424+240 in the high stage to be 0.46-0.67 in the PLLP EED, roughly consistent with that in the low stage.

  14. Red mud characterization using nuclear analytical techniques

    International Nuclear Information System (INIS)

    Obhodas, J.; Sudac, D.; Matjacic, L.; Valkovic, V.

    2011-01-01

    Red mud is a toxic waste left as a byproduct in aluminum production Bayer process. Since it contains significant concentrations of other chemical elements interesting for industry, including REE, it is also potential secondary ore source. Recent events in some countries have shown that red mud presents a serious environmental hazard if not properly stored. The subject of our study is the red mud from an ex-aluminum plant in Obrovac, Croatia, left from processing of bauxite mined during late 70's and early 80's at the eastern Adriatic coast and since than stored in open concrete basins for more than 30 years. We have used energy dispersive x-ray fluorescence analysis (both tube and radioactive source excitation), fast neutron activation analysis and passive gamma spectrometry to identify a number of elements present in the red mud, their concentration levels and radioactivity in the red mud. The high concentrations of Al, Si, Ca, Ti and Fe have been measured. Chemical elements Sc, Cr, Mn, Co, Ni, Cu, Zn, Ga, As, Se, Br, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Pb, Th and U were found in lower concentrations. No significant levels of radioactivity have been measured. (authors)

  15. Features of Red Sea Water Masses

    Science.gov (United States)

    Kartadikaria, Aditya; Hoteit, Ibrahim

    2015-04-01

    Features of Red Sea water mass can be divided into three types but best to be grouped into two different classes that are split at the potential density line σθ=27.4. The surface water (0-50 m) and the intermediate water (50-200 m) have nearly identical types of water mass. They appear as a maxima salinity layer for the water mass that has σθ > 26.0, and as a minimum salinity layer for water mass that has σθ water masses are strongly affected by mixing that is controlled by seasonal variability, fresh water intrusion of the Gulf of Aden Intermediate Water (GAIW), and eddies variability. Two types of mixing; isopycnal and diapycnal mixing are part of important physical phenomena that explain the change of water mass in the Red Sea. The isopycnal mixing occurs at the neutral potential density line, connecting the Red Sea with its adjacent channel, the Gulf of Aden. Diapycnal mixing is found as a dominant mixing mode in the surface of the Red Sea Water and mainly due to energetic eddy activity. Density gradients, across which diapycnal mixing occurs, in the Red Sea are mainly due to large variations in salinity. The isolation of an extreme haline water mass below the thermocline contributes to the generation of the latitudinal shift and low diapycnal mixing. This finding further explains the difference of spatial kinetic mixing between the RSW and the Indian Ocean basin.

  16. Shape memory of human red blood cells.

    Science.gov (United States)

    Fischer, Thomas M

    2004-05-01

    The human red cell can be deformed by external forces but returns to the biconcave resting shape after removal of the forces. If after such shape excursions the rim is always formed by the same part of the membrane, the cell is said to have a memory of its biconcave shape. If the rim can form anywhere on the membrane, the cell would have no shape memory. The shape memory was probed by an experiment called go-and-stop. Locations on the membrane were marked by spontaneously adhering latex spheres. Shape excursions were induced by shear flow. In virtually all red cells, a shape memory was found. After stop of flow and during the return of the latex spheres to the original location, the red cell shape was biconcave. The return occurred by a tank-tread motion of the membrane. The memory could not be eliminated by deforming the red cells in shear flow up to 4 h at room temperature as well as at 37 degrees C. It is suggested that 1). the characteristic time of stress relaxation is >80 min and 2). red cells in vivo also have a shape memory.

  17. Features of Red Sea Water Masses

    KAUST Repository

    Kartadikaria, Aditya R.

    2015-04-01

    Features of Red Sea water mass can be divided into three types but best to be grouped into two different classes that are split at the potential density line σθ=27.4. The surface water (0-50 m) and the intermediate water (50-200 m) have nearly identical types of water mass. They appear as a maxima salinity layer for the water mass that has σθ > 26.0, and as a minimum salinity layer for water mass that has σθ < 26.0. These types of water masses are strongly affected by mixing that is controlled by seasonal variability, fresh water intrusion of the Gulf of Aden Intermediate Water (GAIW), and eddies variability. Two types of mixing; isopycnal and diapycnal mixing are part of important physical phenomena that explain the change of water mass in the Red Sea. The isopycnal mixing occurs at the neutral potential density line, connecting the Red Sea with its adjacent channel, the Gulf of Aden. Diapycnal mixing is found as a dominant mixing mode in the surface of the Red Sea Water and mainly due to energetic eddy activity. Density gradients, across which diapycnal mixing occurs, in the Red Sea are mainly due to large variations in salinity. The isolation of an extreme haline water mass below the thermocline contributes to the generation of the latitudinal shift and low diapycnal mixing. This finding further explains the difference of spatial kinetic mixing between the RSW and the Indian Ocean basin.

  18. Male red ornamentation is associated with female red sensitivity in sticklebacks.

    Directory of Open Access Journals (Sweden)

    Ingolf P Rick

    Full Text Available Sexual selection theory proposes correlated evolutionary changes in mating preferences and secondary sexual characters based on a positive genetic correlation between preference and the preferred trait. Empirical work has provided support for a genetic covariation between female preference and male attractiveness in several taxa. Here, we study parent and offspring visual traits in threespine sticklebacks, Gasterosteus aculeatus. While focusing on the proximate basis of mating preferences, we compare the red breeding coloration of males, which strongly contributes to female choice, with their daughters' red sensitivity measured by optomotor response thresholds. We show that the red color expression of fathers correlates well with their daughters' red sensitivity. Given that a within-population genetic correlation between signal and preference was experimentally confirmed for the red coloration in sticklebacks, our results indicate a proximate mechanism in terms of perceptual sensitivity being involved in the co-evolution of female preferences and male mating signals.

  19. Fusion power

    International Nuclear Information System (INIS)

    Hancox, R.

    1981-01-01

    The principles of fusion power, and its advantages and disadvantages, are outlined. Present research programmes and future plans directed towards the development of a fusion power reactor, are summarized. (U.K.)

  20. Power Electronics

    DEFF Research Database (Denmark)

    Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

    2008-01-01

    is to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most...... emerging renewable energy sources, wind energy, which by means of power electronics are changing from being a minor energy source to be acting as an important power source in the energy system. Power electronics is the enabling technology and the presentation will cover the development in wind turbine...... technology from kW to MW, discuss which power electronic solutions are most feasible and used today....

  1. Normative Power

    DEFF Research Database (Denmark)

    's normative power than any other academic journal, including a special issue on "What Kind of Power?" in 2006. As the leading journal in the debate, this special issue brings together seven normative power articles published in JEPP since the 2006 special issue, together with Ian Manners' ‘Normative power......The social sciences have many different understandings of ‘normative power', but in European Union (EU) studies normative power has three particular meanings. The first meaning of normative power is its emphasis on normative theory, that is, how we judge and justify truth claims in social science...... effects of EU relations with the world in areas ranging from inter-regional relations, through traditional diplomacy, to environmental politics. Research areas of particular interest include the study of the interplay between physical, material and normative forms of power, as well as the constitutive...

  2. Limitations of red noise in analysing Dansgaard-Oeschger events

    Directory of Open Access Journals (Sweden)

    H. Braun

    2010-02-01

    Full Text Available During the last glacial period, climate records from the North Atlantic region exhibit a pronounced spectral component corresponding to a period of about 1470 years, which has attracted much attention. This spectral peak is closely related to the recurrence pattern of Dansgaard-Oeschger (DO events. In previous studies a red noise random process, more precisely a first-order autoregressive (AR1 process, was used to evaluate the statistical significance of this peak, with a reported significance of more than 99%. Here we use a simple mechanistic two-state model of DO events, which itself was derived from a much more sophisticated ocean-atmosphere model of intermediate complexity, to numerically evaluate the spectral properties of random (i.e., solely noise-driven events. This way we find that the power spectral density of random DO events differs fundamentally from a simple red noise random process. These results question the applicability of linear spectral analysis for estimating the statistical significance of highly non-linear processes such as DO events. More precisely, to enhance our scientific understanding about the trigger of DO events, we must not consider simple "straw men" as, for example, the AR1 random process, but rather test against realistic alternative descriptions.

  3. Red Indian Lake fishway, an innovative design for difficult conditions

    International Nuclear Information System (INIS)

    Helwig, P.C.; Goosney, R.; Smith, W.L.

    1993-01-01

    Red Indian Lake Dam is a large concrete gravity structure, 10-12 m high and 245 m long, in the Exploits River watershed in Newfoundland. The watershed is an ideal habitat for production of Atlantic salmon. Since 1985, the watershed above the dam has undergone an extensive stocking program to optimize the salmon production capacity of the upper reaches of the system. To sustain this development, a fishway was needed to permit returning salmon to bypass Red Indian Lake Dam, the last remaining migrational barrier. The difficulties with installing a fishway at the dam site included extreme variation in upstream water levels, the need to retrofit a fishway into an existing structure, and the necessity to attract fish into the fishway in competition with other flows from power plant, spillway, or waterfall. After examining several design approaches, an innovative design was developed incorporating two separate but interrelated flow ways: one to handle attraction water and the other for transportation water. The latter passage leads to a trap at the upper end of the fishway from which salmon are hoisted via a hopper/monorail system across the dam and into the lake. Construction of the fishway was staged over four phases between December 1985 and December 1988. 3 refs., 1 fig

  4. Genetic characterization of some Romanian red wine grapevine varieties

    Science.gov (United States)

    Ghetea, Ligia Gabriela; Motoc, Rozalia Magda; Niculescu, Ana-Maria; Litescu, Simona Carmen; Duma, Virgil-Florin; Popescu, Carmen Florentina

    2008-04-01

    In our study we have considered three of the most valuable Romanian red wine grapevine cultivars: Feteasca neagra, Feteasca alba and Novac. We have chosen to study grapevine because grapes and wine are an important part of a healthy diet, and because red grapes have the highest content of proanthocyanidins, that act as antioxidants (free radical scavengers) in the human body. Proanthocyanidins possess anti-mutagenic, anti-tumor, anti-viral activities and they present many other confirmed or potential benefits. Genotyping method was applied in order to asses the genetic profile at 14 microsatellite loci, for two cultivars: Feteasca neagra and Feteasca alba. In order to achieve this, the HPLC-DAD method was used. The content of anthocyans in grape skin from two cultivars - Feteasca neagra and Novac - was measured. Microsatellite markers have been certified as powerful tools for assessing genetic identities and genetic relationships between grapevine gene pools. Genetic characterization of grapevine cultivars can certify their authenticity and purity, two features that have a direct effect on the quality and value of the finished product, the wine. In our country, this is the first attempt in order to establish a genetic profile for valuable Romanian origin grapevine varieties. In some of the 14 microsatellitic loci, Feteasca neagra and Feteasca alba cultivars presented allele size variants different from the values cited in the literature, proving that these cultivars belong to a geographical distinct gene pool. The content of anthocyans in Feteasca neagra grape skin was significantly higher than in Novac.

  5. Empirically Calibrated Asteroseismic Masses and Radii for Red Giants in the Kepler Fields

    Science.gov (United States)

    Pinsonneault, Marc; Elsworth, Yvonne; Silva Aguirre, Victor; Chaplin, William J.; Garcia, Rafael A.; Hekker, Saskia; Holtzman, Jon; Huber, Daniel; Johnson, Jennifer; Kallinger, Thomas; Mosser, Benoit; Mathur, Savita; Serenelli, Aldo; Shetrone, Matthew; Stello, Dennis; Tayar, Jamie; Zinn, Joel; APOGEE Team, KASC Team, APOKASC Team

    2018-01-01

    We report on the joint asteroseismic and spectroscopic properties of a sample of 6048 evolved stars in the fields originally observed by the Kepler satellite. We use APOGEE spectroscopic data taken from Data Release 13 of the Sloan Digital Sky Survey, combined with asteroseismic data analyzed by members of the Kepler Asteroseismic Science Consortium. With high statistical significance, the different pipelines do not have relative zero points that are the same as the solar values, and red clump stars do not have the same empirical relative zero points as red giants. We employ theoretically motivated corrections to the scaling relation for the large frequency spacing, and adjust the zero point of the frequency of maximum power scaling relation to be consistent with masses and radii for members of star clusters. The scatter in calibrator masses is consistent with our error estimation. Systematic and random mass errors are explicitly separated and identified. The measurement scatter, and random uncertainties, are three times larger for red giants where one or more technique failed to return a value than for targets where all five methods could do so, and this is a substantial fraction of the sample (20% of red giants and 25% of red clump stars). Overall trends and future prospects are discussed.

  6. 2D fluorescence spectroscopy for monitoring ion-exchange membrane based technologies - Reverse electrodialysis (RED).

    Science.gov (United States)

    Pawlowski, Sylwin; Galinha, Claudia F; Crespo, João G; Velizarov, Svetlozar

    2016-01-01

    Reverse electrodialysis (RED) is one of the emerging, membrane-based technologies for harvesting salinity gradient energy. In RED process, fouling is an undesirable operation constraint since it leads to a decrease of the obtainable net power density due to increasing stack electric resistance and pressure drop. Therefore, early fouling detection is one of the main challenges for successful RED technology implementation. In the present study, two-dimensional (2D) fluorescence spectroscopy was used, for the first time, as a tool for fouling monitoring in RED. Fluorescence excitation-emission matrices (EEMs) of ion-exchange membrane surfaces and of natural aqueous streams were acquired during one month of a RED stack operation. Fouling evolvement on the ion-exchange membrane surfaces was successfully followed by 2D fluorescence spectroscopy and quantified using principal components analysis (PCA). Additionally, the efficiency of cleaning strategy was assessed by measuring the membrane fluorescence emission intensity before and after cleaning. The anion-exchange membrane (AEM) surface in contact with river water showed to be significantly affected due to fouling by humic compounds, which were found to cross through the membrane from the lower salinity (river water) to higher salinity (sea water) stream. The results obtained show that the combined approach of using 2D fluorescence spectroscopy and PCA has a high potential for studying fouling development and membrane cleaning efficiency in ion exchange membrane processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Fast and Simple Forensic Red Pen Ink Analysis Using Ultra-Performance Liquid Chromatography (UPLC)

    International Nuclear Information System (INIS)

    Lee, L.C.; Ying, S.L.; Wan Nur Syazwani Wan Mohamad Fuad; Ab Aziz Ishak; Khairul Osman

    2016-01-01

    Ultra-performance liquid chromatography (UPLC) is more effective than high performance liquid chromatography in terms of analysis speed and sensitivity. This paper presents a feasibility study on forensic red pen inks analysis using UPLC. A total of 12 varieties of red ball point pen inks were purchased from selected stationary shop. For each variety, four different individual pens were sampled to provide intra-variability within a particular variety of pen. The proposed approach is very simple that it only involved limited analysis step and chemicals. A total of 144 chromatograms were obtained from red ink entries extracted with 1.5 mL 80 % (v/v) acetonitrile. Peaks originated from pen inks were determined by comparing the chromatograms of both blank paper and blank solvent against that of ink samples. Subsequently, one-way ANOVA was conducted to discriminate all 66 possible pairs for red pen inks. Results showed that the proposed approach giving discriminating power of 95.45 %. The outcome of the study indicates that UPLC could be a fast and simple approach to red ball point pen inks analysis. (author)

  8. Power marketing

    International Nuclear Information System (INIS)

    Sioshansi, F.P.; Altman, A.M.

    1998-01-01

    One of the most significant developments in the US electric power industry in recent years has been the phenomenal growth of power marketing. What was barely a blimp on the radar screen in 1992 has turned out to be a jumbo jet. This article explains what is power marketing who are power marketers, what role play these players and what will be their longer-term impact on the traditional industry [it

  9. Power program and nuclear power

    International Nuclear Information System (INIS)

    Chernilin, Yu.F.

    1990-01-01

    Main points of the USSR power program and the role of nuclear power in fuel and power complex of the country are considered. Data on dynamics of economic indices of electric power generation at nuclear power plants during 1980-1988 and forecasts till 2000 are presented. It is shown that real cost of 1 kW/h of electric power is equal to 1.3-1.8 cop., and total reduced cost is equal to 1.8-2.4 cop

  10. Power Electronics

    Indian Academy of Sciences (India)

    They cover a wide spectrum of areas from power supplies to power system ... Ramanarayanan describe the modelling and design of a family of soft transition ... of power when the drive is operating in the braking mode and fast dynamic response. ... time models are extremely important, as they can be included in real time ...

  11. Power Outages

    Science.gov (United States)

    ... Publications Emergency Alerts Preparedness Portal Preparedness Messaging Calendar Social Media Preparedness Toolkits Preparedness News Languages About Us Build a Kit Close Search Enter Search Term(s): Main Content Home Be Informed Power Outages Power Outages Extended power outages may impact ...

  12. Great red spot dependence on solar activity

    International Nuclear Information System (INIS)

    Schatten, K.H.

    1979-01-01

    A new inquiry has been made into the question of whether Jupiter's Great Red Spot shows a solar activity dependence. From 1892 to 1947 a clear correlation was present. A dearth of sightings in the seventeenth century, along with the Maunder Minimum, further supports the relation. An anticorrelation, however, from l948 to l967 removed support for such an effect. The old observations have reexamined and recent observations have also been studied. The author reexamines this difficult question and suggests a possible physical mechanism for a Sun-Jovian weather relation. Prinn and Lewis' conversion reaction of Phosphine gas to triclinic red phosphorous crystals is a reaction dependent upon solar radiation. It may explain the dependence found, as well as the striking appearance of the Great Red Spot in the UV

  13. Seasonal Overturning Circulation in the Red Sea

    Science.gov (United States)

    Yao, F.; Hoteit, I.; Koehl, A.

    2010-12-01

    The Red Sea exhibits a distinct seasonal overturning circulation. In winter, a typical two-layer exchange structure, with a fresher inflow from the Gulf of Aden on top of an outflow from the Red Sea, is established. In summer months (June to September) this circulation pattern is changed to a three-layer structure: a surface outflow from the Red Sea on top of a subsurface intrusion of the Gulf of Aden Intermediate Water and a weakened deep outflow. This seasonal variability is studied using a general circulation model, MITgcm, with 6 hourly NCEP atmospheric forcing. The model is able to reproduce the observed seasonal variability very well. The forcing mechanisms of the seasonal variability related to seasonal surface wind stress and buoyancy flux, and water mass transformation processes associated with the seasonal overturning circulation are analyzed and presented.

  14. 'Rosy Red' Soil in Phoenix's Scoop

    Science.gov (United States)

    2008-01-01

    This image shows fine-grained material inside the Robotic Arm scoop as seen by the Robotic Arm Camera (RAC) aboard NASA's Phoenix Mars Lander on June 25, 2008, the 30th Martian day, or sol, of the mission. The image shows fine, fluffy, red soil particles collected in a sample called 'Rosy Red.' The sample was dug from the trench named 'Snow White' in the area called 'Wonderland.' Some of the Rosy Red sample was delivered to Phoenix's Optical Microscope and Wet Chemistry Laboratory for analysis. The RAC provides its own illumination, so the color seen in RAC images is color as seen on Earth, not color as it would appear on Mars. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  15. Red textures and the work of juxtaposition

    Directory of Open Access Journals (Sweden)

    Corinne A. Kratz

    Full Text Available Simon Gush's evocative work Red is an installation, an exhibit, a film, a website, and a provocation to think about what these different forms convey and do, and how they do so. What kinds of engagement, work and knowledge production are involved in curating, designing and creating work in different formats, each of which combines varied media and forms of expression? This article considers the design and interpretive possibilities of Red's different forms, paying particular attention to juxtaposition as a fundamental technique in designing and constructing exhibits, films and websites. The analysis examines the layerings, interactions, timings and textures involved and draws in other exhibitions to highlight the ways that Red and history museums approach their work and relations to time, history and historiography.

  16. Effects of He-Ne laser irradiation on red blood cells in vitro

    Science.gov (United States)

    Ghadage, Vijay H.; Kulkarni, Gauri R.

    2011-03-01

    Laser radiation has many applications in biomedical field, such as wound healing, tissue repairing, heating and ablation processes. Intravenous low power laser radiation is used clinically for skin and vascular disorders. Laser radiation improves microcirculation and modulates the rheological properties of blood. FTIR (Fourier Transform Infra Red Spectra) is used to see the structural changes in erythrocyte membrane. In the present work He Ne laser (λ= 632nm, power=2mW) is used to irradiate human Red blood cells. Red blood cells are separated from human whole blood using centrifugation method (time=10 min., temperature=15°C and RPM=3000) and then exposed to HeNe laser radiation. Laser exposure time is varied from 10 min. to 40min for Red blood cells. Absorption spectrum, FTIR and fluorescence spectra of RBC are compared before and after HeNe laser irradiation. The absorption spectrum of RBC after exposure to HeNe laser shows a significant decrease in absorbance. The FTIR spectrum of non irradiated RBC clearly show the peaks due to O-H (free group), C=O (amide I group), N=O (nitro group), C-O (anhydride group) and C-H (aromatic group). Laser radiation changes in transmittance in FTIR spectra related to C=O group and percentage of transmittance increases for O-H, C=C, N=O, C-O and C-H group.

  17. Lógicas para la red

    Directory of Open Access Journals (Sweden)

    Antonia HUERTAS

    2009-09-01

    Full Text Available RESUMEN: Tim Berners-Lee y sus colegas del World Wide Web Consortium (W3C llamaron «Semantic Web» al que sería el siguiente estadio de desarrollo de la red (inevitablemente traducido al castellano como Web Semántica. La idea detrás de esta evolución de la red es extender con metadatos y reglas lógicas la red basada en el lenguaje html, con el objetivo de que la infraestructura resultante permita a las máquinas entender los datos de la red de la misma forma que los entendemos los humanos. Así, añadir lógica a la red permitiría a los ordenadores tomar decisiones, hacer inferencias y responder preguntas. En este texto se pretende revisar las lógicas que han sido propuestas para permitir esta nueva web inteligente y repasar las cuestiones teóricas y pragmáticas más importantes de la corta pero intensa historia de las lógicas para la red.ABSTRACT: Tim Berners-Lee and their colleagues of the World Wide Web Consortium (W3C called «Semantic Web» the next development of the Web. The idea behind this evolution of the Web is to extend the present network based on the HTML language with metadata and logical rules, with the aim of the resulting infrastructure allowing machines to understand Web data in the same way that human beings understand them. Thus, adding logic to the Web would allow the computers to take decisions, to do inferences and to answer questions. In this paper it is intended to revise the logics that have been suggested to allow this new intelligent Web and to revise the most important theoretical and pragmatic questions of the short but intense history of logics for the Web.

  18. Radio universitaria: trabajo en red como imperativo

    Directory of Open Access Journals (Sweden)

    Tiziana Cavallo

    2014-01-01

    Full Text Available Trabajo en red es un concepto clave en la radio universitaria, tanto desde el punto de vista individual como del colectivo. A través de dos estudios de caso, enfocados en la radio universitaria de Italia y de Colombia, este artículo muestra cómo el trabajo en red ha sido decisivo para el fortalecimiento de su función, la ampliación de su impacto, la conformación de su identidad y el crecimiento de su visibilidad en las sociedades en las cuales desarrollan su labor.

  19. Oenology: red wine procyanidins and vascular health.

    Science.gov (United States)

    Corder, R; Mullen, W; Khan, N Q; Marks, S C; Wood, E G; Carrier, M J; Crozier, A

    2006-11-30

    Regular, moderate consumption of red wine is linked to a reduced risk of coronary heart disease and to lower overall mortality, but the relative contribution of wine's alcohol and polyphenol components to these effects is unclear. Here we identify procyanidins as the principal vasoactive polyphenols in red wine and show that they are present at higher concentrations in wines from areas of southwestern France and Sardinia, where traditional production methods ensure that these compounds are efficiently extracted during vinification. These regions also happen to be associated with increased longevity in the population.

  20. Causes of Red Eye-Uveitis

    Directory of Open Access Journals (Sweden)

    Selçuk Sızmaz

    2012-12-01

    Full Text Available Uveitis, being an important cause of ocular morbidity, must be taken into consideration in the differential diagnosis and the management of patients with red eye. Uveitis entities can demonstrate variable clinical features. Patients presenting with uveitis must undergo careful systemic evaluation for exact diagnosis and treatment. Studies for standardization of uveitis with variable clinical pictures are emerging. Acute anterior uveitis and panuveitis can cause red eye. The purpose of this current study is to summarize the clinical features and laboratory investigations that could help the differential diagnosis of acute anterior uveitis and panuveitis cases. (Turk J Ophthalmol 2012; 42: Supplement 57-62

  1. Incorporation of flat glass in red ceramic

    International Nuclear Information System (INIS)

    Caldas, T.C.C.; Morais, A.S.C.; Pereira, P.S.; Monteiro, S.N.; Vieira, C.M.F.

    2011-01-01

    This work have as objective evaluate the effect of incorporation of up to 10% by weight of powdered flat glass , from civil industry, in red ceramic. The bodies were obtained by uniaxial pressing at 20 MPa and fired at temperatures of 850 ° C and 1050 ° C. The parameters studied were linear firing shrinkage, apparent density, water absorption and flexural rupture stress for the evaluation of the mechanical physical properties. The microstructure was observed by scanning electron microscopy and phase identification was performed by X-ray diffraction. The results showed that the waste changes the microstructure and properties of red ceramics. (author)

  2. Pseudoepitheliomatous Hyperplasia in a Red Pigment Tattoo

    Science.gov (United States)

    Kazlouskaya, Viktoryia

    2015-01-01

    Red pigment tattoos are known to cause pseudoepitheliomatous hyperplasia in the skin, frequently simulating squamous cell carcinoma or keratoacanthoma. Herein, the authors present two additional cases of red pigment tattoo pseudoepitheliomatous hyperplasia in which they noted a lichenoid tissue reaction. They reviewed the previously published cases and observed a lichenoid reaction in the histopathological images similar to hypertrophic lichen planus. The authors suggest that these reactions might best be referred to as “lichenoid reaction with pseudoepitheliomatous hyperplasia” or “hypertrophic lichen planus-like reaction.” Accordingly, recognition of an inflammatory component may allow additional treatment options. PMID:26705448

  3. Recovery of rare earths from red mud

    International Nuclear Information System (INIS)

    Bautista, R.G.

    1992-01-01

    The prospect for the recovery of rare earths from red mud, the bauxite tailings from the production of alumina is examined. The Jamaican red mud by far has the higher trace concentrations of lanthanum, cerium, neodymium, and yttrium. Scandium is also present. The dissolution of the rare earth is a major extraction problem because of the large volume of other materials. The recovery processes that have been proposed include the production of co-products such as iron, alumina, and titanium concentrates, with the rare earths going with the titanium. In this paper a critical examination of the possible processes are presented with the recommended research projects to be carried out

  4. Nuclear Power

    International Nuclear Information System (INIS)

    Douglas-Hamilton, J.; Home Robertson, J.; Beith, A.J.

    1987-01-01

    In this debate the Government's policy on nuclear power is discussed. Government policy is that nuclear power is the safest and cleanest way of generating electricity and is cheap. Other political parties who do not endorse a nuclear energy policy are considered not to be acting in the people's best interests. The debate ranged over the risks from nuclear power, the UK safety record, safety regulations, and the environmental effects of nuclear power. The Torness nuclear power plant was mentioned specifically. The energy policy of the opposition parties is strongly criticised. The debate lasted just over an hour and is reported verbatim. (UK)

  5. Evaluation of Red Light Camera Enforcement at Signalized Intersections

    Directory of Open Access Journals (Sweden)

    Abdulrahman AlJanahi

    2007-12-01

    Full Text Available The study attempts to find the effectiveness of adopting red light cameras in reducing red light violators. An experimental approach was adopted to investigate the use of red light cameras at signalized intersections in the Kingdom of Bahrain. The study locations were divided into three groups. The first group was related to the approaches monitored with red light cameras. The second group was related to approaches without red light cameras, but located within an intersection that had one of its approaches monitored with red light cameras. The third group was related to intersection approaches located at intersection without red light cameras (controlled sites. A methodology was developed for data collection. The data were then tested statistically by Z-test using proportion methods to compare the proportion of red light violations occurring at different sites. The study found that the proportion of red light violators at approaches monitored with red light cameras was significantly less than those at the controlled sites for most of the time. Approaches without red light cameras located within intersections having red light cameras showed, in general, fewer violations than controlled sites, but the results were not significant for all times of the day. The study reveals that red light cameras have a positive effect on reducing red light violations. However, these conclusions need further evaluations to justify their safe and economic use.

  6. Power Talk

    DEFF Research Database (Denmark)

    Angjelichinoski, Marko; Stefanovic, Cedomir; Popovski, Petar

    2016-01-01

    A standard way to realize communication in microgrid control is to use an external communication network, such as modems for wireless or power-line communication, whose implementation may be inefficient in terms of deployment cost, complexity, and system stability. In this chapter we present......, while its reliability and availability draw on the reliability and availability of the microgrid power transmission system....... a communication solution, denoted as power talk, which is solely based on the use of the existing microgrid power equipment (i.e., power electronics and buses). The pivotal idea is to modulate information in the power-related parameters of the microgrid buses by use of the flexibility of power electronic...

  7. Nuclear power

    International Nuclear Information System (INIS)

    Porter, Arthur.

    1980-01-01

    This chapter of the final report of the Royal Commission on Electric Power Planning in Ontario updates its interim report on nuclear power in Ontario (1978) in the light of the Three Mile Island accident and presents the commission's general conclusions and recommendations relating to nuclear power. The risks of nuclear power, reactor safety with special reference to Three Mile Island and incidents at the Bruce generating station, the environmental effects of uranium mining and milling, waste management, nuclear power economics, uranium supplies, socio-political issues, and the regulation of nuclear power are discussed. Specific recommendations are made concerning the organization and public control of Ontario Hydro, but the commission concluded that nuclear power is acceptable in Ontario as long as satisfactory progress is made in the disposal of uranium mill tailings and spent fuel wastes. (LL)

  8. Study of ocean red tide multi-parameter monitoring technology based on double-wavelength airborne lidar system

    Science.gov (United States)

    Lin, Hong; Wang, Xinming; Liang, Kun

    2010-10-01

    For monitoring and forecasting of the ocean red tide in real time, a marine environment monitoring technology based on the double-wavelength airborne lidar system is proposed. An airborne lidar is father more efficient than the traditional measure technology by the boat. At the same time, this technology can detect multi-parameter about the ocean red tide by using the double-wavelength lidar.It not only can use the infrared laser to detect the scattering signal under the water and gain the information about the red tise's density and size, but also can use the blue-green laser to detect the Brillouin scattering signal and deduce the temperature and salinity of the seawater.The red tide's density detecting model is firstly established by introducing the concept about the red tide scattering coefficient based on the Mie scattering theory. From the Brillouin scattering theory, the relationship about the blue-green laser's Brillouin scattering frequency shift value and power value with the seawater temperature and salinity is found. Then, the detecting mode1 of the saewater temperature and salinity can be established. The value of the red tide infrared scattering signal is evaluated by the simulation, and therefore the red tide particles' density can be known. At the same time, the blue-green laser's Brillouin scattering frequency shift value and power value are evaluated by simulating, and the temperature and salinity of the seawater can be known. Baed on the multi-parameters, the ocean red tide's growth can be monitored and forecasted.

  9. Raman spectroscopic studies of optically trapped red blood cells

    International Nuclear Information System (INIS)

    Dasgupta, R.; Gupta, P.K.

    2010-01-01

    Raman spectroscopic studies were performed on optically trapped red blood cells (RBCs) collected from healthy volunteers and patients suffering from malaria (Plasmodium vivax infection) using near infrared (785 nm) laser source. The results show significant alteration in the spectra averaged over ∼ 50 non-parasitized RBCs per sample. As compared to RBCs from healthy donors, in cells collected from malaria patients, a significant decrease in the intensity of the low spin (oxygenated-haemoglobin) marker Raman band at 1223 cm -1 (υ 13 or υ 42 ) along with a concomitant increase in the high spin (deoxygenated-haemoglobin) marker bands at 1210 cm -1 (υ 5 + υ 18 ) and 1546 cm -1 (υ 11 ) was observed. The changes primarily suggest a reduced haemoglobin-oxygen affinity for the non-parasitized red cells in malaria patients. The possible causes include up regulation of intra-erythrocytic 2,3-diphosphoglycerate and/or ineffective erythropoiesis resulted from the disease. During the above study we also observed that significant photo-damage may results to the intracellular haemoglobin (Hb) if higher laser power is used. For a laser power above ∼ 5 mW the observed increase in intensity of the Raman bands at 975 cm -1 (υ 46 ), 1244 cm -1 (υ 42 ) and 1366 cm -1 (υ 4 ) with increasing exposure time suggests photo-denaturation of Hb and the concomitant decrease in intensity of the Raman band at 1544 cm -1 (υ 11 ) suggests photo induced methaemoglobin formation. The photo damage of intracellular haemoglobin by the above processes was also observed to result in intracellular heme aggregation. (author)

  10. ESR analysis of irradiated red peppers and commercial red peppers in Japan

    International Nuclear Information System (INIS)

    Kameya, Hiromi; Ukai, Mitsuko

    2011-01-01

    ESR analysis of γ-ray irradiated and being treated with different processing red pepper was studied. All the red peppers were commercial expect irradiated one. Processing treatment of red pepper was sun drying, mechanical processing (heating sterilization and powdering treatment). All the samples were weighted and analyzed. The ESR spectrum of the red pepper is composed of a singlet at g=2.00. This signal was originated from organic free radical. It is suggested the effect of heating treatment on the radical formation is not so large and powdering treatment will promote the radical formation of red pepper. ESR singlet signal of the irradiated red pepper showed the large signal intensity and the dose-dependence. The singlet signal intensity of irradiated powder sample showed the almost same value as compared with that of the powder sample with heating treatment. Relaxation times (T 1 and T 2 ) of the singlet signal were calculated. The relaxation behavior and relaxation times of the irradiated sample were different from that of the non-irradiated sample. The value of T 1 , the spin lattice relaxation time, of irradiated sample was increased and T 2 , the spin-spin relaxation time, of irradiated sample was decreased. We concluded that the radical formation of the red pepper is mainly depended on the powdering treatment and irradiation. (author)

  11. Stockholm Power Tech. Power systems

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    The proceedings from this symposium is presented in six volumes: Invited speakers` sessions; Power systems; Power electronics; High-voltage technology; Electrical machines and drives; and Information and control systems. This report covers the power systems volume. Separate abstracts have been prepared for 141 of the 145 papers in this volume

  12. Stockholm Power Tech. Power systems

    International Nuclear Information System (INIS)

    1995-01-01

    The proceedings from this symposium is presented in six volumes: Invited speakers' sessions; Power systems; Power electronics; High-voltage technology; Electrical machines and drives; and Information and control systems. This report covers the power systems volume. Separate abstracts have been prepared for 141 of the 145 papers in this volume

  13. RED Alert – Early warning or detection of global re-emerging infectious disease (RED)

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, Alina [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-07-13

    This is the PDF of a presentation for a webinar given by Los Alamos National Laboratory (LANL) on the early warning or detection of global re-emerging infectious disease (RED). First, there is an overview of LANL biosurveillance tools. Then, information is given about RED Alert. Next, a demonstration is given of a component prototype. RED Alert is an analysis tool that can provide early warning or detection of the re-emergence of an infectious disease at the global level, but through a local lens.

  14. Thermal degradation of glucosinolates in red cabbage

    NARCIS (Netherlands)

    Oerlemans, K.; Barrett, D.M.; Bosch Suades, C.; Verkerk, R.; Dekker, M.

    2006-01-01

    Thermal degradation of individual glucosinolates within the plant matrix was studied. Red cabbage samples were heated at different temperatures for various times. To rule out the influence of enzymatic breakdown and to focus entirely on the thermal degradation of glucosinolates, myrosinase was

  15. South African red data book - Aves

    CSIR Research Space (South Africa)

    Siegfried, WR

    1976-06-01

    Full Text Available Data sheets are provided on 101 South African bird species thought to be eligible for conservation attention. A list is also provided of 35 species which might qualify for inclusion in a revised South African Red Data Book....

  16. Red Wine, Resveratrol and Atrial Fibrillation

    Science.gov (United States)

    Garavaglia, Juliano; Marcadenti, Aline

    2017-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as an inhibitor of both intracellular calcium release and pathological signaling cascades in AF, eliminating calcium overload and preserving the cardiomyocyte contractile function. However, there are still no clinical trials at all that prove that resveratrol supplementation leads to improved outcomes. Besides, no observational study supports a beneficial effect of light or moderate alcohol intake and a lower risk of AF. The purpose of this review is to briefly describe possible beneficial effects of red wine and resveratrol in AF, and also present studies conducted in humans regarding chronic red wine consumption, resveratrol, and AF. PMID:29084143

  17. Red Wine, Resveratrol and Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Laura Siga Stephan

    2017-10-01

    Full Text Available Atrial fibrillation (AF is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as an inhibitor of both intracellular calcium release and pathological signaling cascades in AF, eliminating calcium overload and preserving the cardiomyocyte contractile function. However, there are still no clinical trials at all that prove that resveratrol supplementation leads to improved outcomes. Besides, no observational study supports a beneficial effect of light or moderate alcohol intake and a lower risk of AF. The purpose of this review is to briefly describe possible beneficial effects of red wine and resveratrol in AF, and also present studies conducted in humans regarding chronic red wine consumption, resveratrol, and AF.

  18. Chemical basal treatment to control red alder.

    Science.gov (United States)

    Robert H. Ruth; Carl M. Berntsen

    1956-01-01

    A key to better restocking of conifers on recently cutover forest land in the Oregon Coast Range is the elimination of competition from red alder (Alnus rubra Bong.). This can be readily accomplished with a foliage spray containing 2,4-dichlorophenoxyacetic acid (2.4-D). Tests in 1954 and 1955 on the Cascade Head Experimental Forest have shown that...

  19. Red Wine Polyphenols and Vascular Function

    NARCIS (Netherlands)

    I.P.G. Botden (Ilse)

    2012-01-01

    textabstractHippocrates, the father of modern medicine, said many centuries ago: “let food be your medicine.” Today, this quote still shows its value, amongst others by the !nding that red wine consumption attributes to a healthy life style, reducing the risk to develop cardiovascular diseases.

  20. Red Wine, Resveratrol and Atrial Fibrillation.

    Science.gov (United States)

    Stephan, Laura Siga; Almeida, Eduardo Dytz; Markoski, Melissa Medeiros; Garavaglia, Juliano; Marcadenti, Aline

    2017-10-30

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as an inhibitor of both intracellular calcium release and pathological signaling cascades in AF, eliminating calcium overload and preserving the cardiomyocyte contractile function. However, there are still no clinical trials at all that prove that resveratrol supplementation leads to improved outcomes. Besides, no observational study supports a beneficial effect of light or moderate alcohol intake and a lower risk of AF. The purpose of this review is to briefly describe possible beneficial effects of red wine and resveratrol in AF, and also present studies conducted in humans regarding chronic red wine consumption, resveratrol, and AF.

  1. Dramatic Change in Jupiter's Great Red Spot

    Science.gov (United States)

    Simon, A. A.; Wong, M. H.; Rogers, J. H.; Orton, G. S.; de Pater, I.; Asay-Davis, X.; Carlson, R. W.; Marcus, P. S.

    2015-01-01

    Jupiter's Great Red Spot (GRS) is one of its most distinct and enduring features, having been continuously observed since the 1800's. It currently spans the smallest latitude and longitude size ever recorded. Here we show analyses of 2014 Hubble spectral imaging data to study the color, structure and internal dynamics of this long-live storm.

  2. Swapping one red pigment for another.

    Science.gov (United States)

    Davies, Kevin M

    2015-01-01

    Betalains are bright red and yellow pigments, which are produced in only one order of plants, the Caryophyllales, and replace the more familiar anthocyanin pigments. The evolutionary origin of betalain production is a mystery, but a new study has identified the first regulator of betalain production and discovered a previously unknown link between the two pigment pathways.

  3. Registration of 'Prevail' hard red spring wheat

    Science.gov (United States)

    Grower and end-user acceptance of new Hard Red Spring Wheat (HRSW; Triticum aestivum L.) cultivars is largely contingent upon satisfactory agronomic performance, end-use quality potential, and disease resistance levels. Additional characteristics, such as desirable plant height, can also contribute...

  4. Nutrient Limitation in Central Red Sea Mangroves

    KAUST Repository

    Almahasheer, Hanan

    2016-12-24

    As coastal plants that can survive in salt water, mangroves play an essential role in large marine ecosystems (LMEs). The Red Sea, where the growth of mangroves is stunted, is one of the least studied LMEs in the world. Mangroves along the Central Red Sea have characteristic heights of ~2 m, suggesting nutrient limitation. We assessed the nutrient status of mangrove stands in the Central Red Sea and conducted a fertilization experiment (N, P and Fe and various combinations thereof) on 4-week-old seedlings of Avicennia marina to identify limiting nutrients and stoichiometric effects. We measured height, number of leaves, number of nodes and root development at different time periods as well as the leaf content of C, N, P, Fe, and Chl a in the experimental seedlings. Height, number of nodes and number of leaves differed significantly among treatments. Iron treatment resulted in significantly taller plants compared with other nutrients, demonstrating that iron is the primary limiting nutrient in the tested mangrove population and confirming Liebig\\'s law of the minimum: iron addition alone yielded results comparable to those using complete fertilizer. This result is consistent with the biogenic nature of the sediments in the Red Sea, which are dominated by carbonates, and the lack of riverine sources of iron.

  5. Science responses to IUCN Red Listing

    Czech Academy of Sciences Publication Activity Database

    Jaric, Ivan; Roberts, D.L.; Gessner, J.; Solow, A.R.; Courchamp, F.

    2017-01-01

    Roč. 5, NOV (2017), č. článku e4025. ISSN 2167-8359 Institutional support: RVO:60077344 Keywords : data deficient * critically endangered * IUCN Red List * endangered species * extinction risk Subject RIV: EG - Zoology OBOR OECD: Zoology Impact factor: 2.177, year: 2016

  6. Sowing pregerminated northern red oak acorns

    Science.gov (United States)

    Richard M. Godman; Gilbert A. Mattson

    1992-01-01

    Northern red oak is extremely difficult to regenerate, although it has produced good acorn crops nearly half of the last 32 years in northern Wisconsin. Field trials have shown that for successful seeding, you must protect acorns from predation by wildlife and sow them when temperatures are most favorable for germination.

  7. Kepler Asteroseismology of Red-giant Stars

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, J.

    2012-01-01

    The Kepler mission, launched in March 2009, has revolutionized asteroseismology, providing detailed observations of thousands of stars. This has allowed in-depth analyses of stars ranging from compact hot subdwarfs to red giants, and including the detection of solar-like oscillations in hundreds ...

  8. Field guide to red tree vole nests

    Science.gov (United States)

    Damon B. Lesmeister; James K. Swingle

    2017-01-01

    Surveys for red tree vole (Arborimus longicaudus) nests require tree climbing because the species is a highly specialized arboreal rodent that live in the tree canopy of coniferous forests in western Oregon and northwestern California. Tree voles are associated with old coniferous forest (≥80 years old) that are structurally complex, but are often...

  9. 39 CFR 259.2 - Red Cross.

    Science.gov (United States)

    2010-07-01

    ... each other, as follows: (1) The Red Cross will use Form 3575, Change of Address Order, as a standard... disaster relief efforts, the Postal Service will establish a separate file of change of address forms... and complete the forms, it will distribute the forms to disaster victims who need them, and it will...

  10. Virtualización en red

    OpenAIRE

    Pallàs Blanco, Leopoldo

    2010-01-01

    En el TFC titulado "Virtualización en Red (agregación de enlaces multichasis)" se realizará tanto el análisis como la comparativa de distintas tecnologías actuales centradas en la agregación de enlaces entre equipos de comunicación.

  11. 21 CFR 184.1121 - Red algae.

    Science.gov (United States)

    2010-04-01

    ... within the following specific limitations: Category of food Maximum level of use in food (as served... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN...

  12. The Red Shoes : Motion picture (1948)

    OpenAIRE

    Lauri Lucente, Gloria; Buhagiar, Celaine

    2011-01-01

    Black Swan : A ballet dancer wins the lead in "Swan Lake" and is perfect for the role of the delicate White Swan - Princess Odette - but slowly loses her mind as she becomes more and more like Odile, the Black Swan. The Red Shoes : A young ballet dancer is torn between the man she loves and her pursuit to become a prima ballerina.

  13. Book Review: Greening in the Red Zone

    Science.gov (United States)

    Nancy. Falxa-Raymond

    2013-01-01

    In the aftermath of a crisis, local, often spontaneous stewardship of nature provides a source of social-ecological resilience to individuals, communities, and ecosystems. This is the concept behind Greening in the Red Zone, and one that may be intuitive to many working in urban forestry, community greening, or any of the local nonprofits or...

  14. Biology and ecology of red alder.

    Science.gov (United States)

    Constance A. Harrington

    2006-01-01

    Red alder is the most common hardwood in the Pacific Northwest with a range stretching from coastal southeast Alaska to southern California and east to isolated populations in Idaho. Soil moisture during the growing season influences where it grows and its growth rates; it can tolerate poor drainage but not droughty, hot sites. Due to its tolerance of wet soil...

  15. Red alder: A bibliography with abstracts

    Science.gov (United States)

    Charles F. Heebner; Mary Jane Bergener

    1983-01-01

    This bibliography lists 661 references to world literature through Hay 1978 containing information about red alder (Alnus rubra Bong.). Included are publications about its taxonomy, biology and silvics, chemical and physical information about its wood and fiber, studies on its nitrogen fixing properties, and reports on industrial uses and economic...

  16. Artificial Red Cells with Polyhemoglobin Membranes.

    Science.gov (United States)

    1981-09-01

    Y. Reciprocal binding of oxygen and diphosphoglycerate by human hemoglobin. Proc. Natl. Acad. Sci. USA 59:526-532, 1968. 12. Bunn, H. F., Seal, U. S...and Scott, A. F. The role of 2,3- diphosphoglycerate in mediating hemoglobin function of mammalian red cells. Ann. N.Y. Acad. Sciences 241:498-519

  17. The FIRST-2MASS Red Quasar Survey

    International Nuclear Information System (INIS)

    Glikman, E; Helfand, D J; White, R L; Becker, R H; Gregg, M D; Lacy, M

    2007-01-01

    Combining radio observations with optical and infrared color selection--demonstrated in our pilot study to be an efficient selection algorithm for finding red quasars--we have obtained optical and infrared spectroscopy for 120 objects in a complete sample of 156 candidates from a sky area of 2716 square degrees. Consistent with our initial results, we find our selection criteria--J-K > 1.7,R-K > 4.0--yield a ∼ 50% success rate for discovering quasars substantially redder than those found in optical surveys. Comparison with UVX- and optical color-selected samples shows that ∼> 10% of the quasars are missed in a magnitude-limited survey. Simultaneous two-frequency radio observations for part of the sample indicate that a synchrotron continuum component is ruled out as a significant contributor to reddening the quasars spectra. We go on to estimate extinctions for our objects assuming their red colors are caused by dust. Continuum fits and Balmer decrements suggest E(B-V) values ranging from near zero to 2.5 magnitudes. Correcting the K-band magnitudes for these extinctions, we find that for K (le) 14.0, red quasars make up between 25% and 60% of the underlying quasar population; owing to the incompleteness of the 2MASS survey at fainter K-band magnitudes, we can only set a lower limit to the radio-detected red quasar population of > 20-30%

  18. Big Red: A Development Environment for Bigraphs

    DEFF Research Database (Denmark)

    Faithfull, Alexander John; Perrone, Gian David; Hildebrandt, Thomas

    2013-01-01

    We present Big Red, a visual editor for bigraphs and bigraphical reactive systems, based upon Eclipse. The editor integrates with several existing bigraph tools to permit simulation and model-checking of bigraphical models. We give a brief introduction to the bigraphs formalism, and show how...

  19. Amdoparvovirus Infection in Red Pandas ( Ailurus fulgens).

    Science.gov (United States)

    Alex, Charles E; Kubiski, Steven V; Li, Linlin; Sadeghi, Mohammadreza; Wack, Raymund F; McCarthy, Megan A; Pesavento, Joseph B; Delwart, Eric; Pesavento, Patricia A

    2018-01-01

    Aleutian mink disease virus is the type species in the genus Amdoparvovirus, and in mink and other Mustelidae can cause either subclinical disease or fatal chronic immune stimulation and immune complex disease. The authors describe a novel amdoparvovirus in the endangered red panda ( Ailurus fulgens), discovered using viral metagenomics. The authors analyzed the prevalence, tissue distribution, and disease association by PCR, in situ hybridization, electron microscopy, and histology in a group of 6 red pandas from a single zoological collection. The study incorporates a fecal shedding survey and analysis of tissues from 4 necropsied animals over a 12-year span. The tentatively named red panda amdoparvovirus (RpAPV) was detected in the feces and/or tissues of all animals tested. At necropsy of 1 geriatric animal, infection was associated with pyogranulomatous peritonitis, pancreatitis, and myocarditis. Other animals had detectable low-level viral nucleic acid in lymph nodes and both oral and intestinal epithelium at the time of necropsy. Full-length genome sequences of RpAPV strains from 2 animals had 12% sequence divergence, demonstrating genetic diversity even among in-contact animals. RpAPV is a persistent infection in this cohort of red pandas, and has variable clinical expression.

  20. Features of Red Sea Water Masses

    KAUST Repository

    Kartadikaria, Aditya R.; Hoteit, Ibrahim

    2015-01-01

    by seasonal variability, fresh water intrusion of the Gulf of Aden Intermediate Water (GAIW), and eddies variability. Two types of mixing; isopycnal and diapycnal mixing are part of important physical phenomena that explain the change of water mass in the Red

  1. Antiproliferative and antibacterial activity evaluation of red ...

    African Journals Online (AJOL)

    Antibacterial activity of these extracts was also tested against Salmonella choleraesuis, Listeria monocytogenes and Staphylococcus aureus. All extracts were obtained from lyophilized biomass of red microalgae. Extract A was obtained using 40% ammonium sulfate precipitation and gel filtration chromatography with G-25 ...

  2. In the Red Shadow of the Earth

    Science.gov (United States)

    Hughes, Stephen W.; Hosokawa, Kazuyuki; Carroll, Joshua; Sawell, David; Wilson, Colin

    2015-01-01

    A technique is described for calculating the brightness of the atmosphere of the Earth that shines into the Earth's umbra during a total lunar eclipse making the Moon red. This "Rim of Fire" is due to refracted unscattered light from all the sunrises and sunsets rimming the Earth. In this article, a photograph of the totally eclipsed…

  3. Why Rudolph's nose is red: Observational study

    NARCIS (Netherlands)

    C. Ince (Can); A.-M. van Kuijen (Anne-Marijevan); D.M.J. Milstein (Dan); K. Yuruk (Koray); L.P. Folkow (Lars P); W.J. Fokkens (Wytske); A.S. Blix (Arnoldus S)

    2012-01-01

    textabstractObjective: To characterise the functional morphology of the nasal microcirculation in humans in comparison with reindeer as a means of testing the hypothesis that the luminous red nose of Rudolph, one of the most well known reindeer pulling Santa Claus's sleigh, is due to the presence of

  4. Red refinements of simplices into congruent subsimplices

    Czech Academy of Sciences Publication Activity Database

    Korotov, S.; Křížek, Michal

    2014-01-01

    Roč. 67, č. 12 (2014), s. 2199-2204 ISSN 0898-1221 R&D Projects: GA ČR GA14-02067S Institutional support: RVO:67985840 Keywords : sommerville tetrahedron * red refinement * higher-dimensional simplex Subject RIV: BA - General Mathematics Impact factor: 1.697, year: 2014 http://www.sciencedirect.com/science/article/pii/S0898122114000662

  5. Simultaneous determination of size and refractive index of red blood cells by light scattering measurements

    International Nuclear Information System (INIS)

    Ghosh, N.; Buddhiwant, P.; Uppal, A.; Majumder, S.K.; Patel, H.S.; Gupta, P.K.

    2006-01-01

    We present a fast and accurate approach for simultaneous determination of both the mean diameter and refractive index of a collection of red blood cells (RBCs). The approach uses the peak frequency of the power spectrum and the corresponding phase angle obtained by performing Fourier transform on the measured angular distribution of scattered light to determine these parameters. Results on the measurement of two important clinical parameters, the mean cell volume and mean cell hemoglobin concentration of a collection of RBCs, are presented

  6. The Red Sea: An Arena for Wind-Wave Modeling in Enclosed Seas

    KAUST Repository

    Langodan, Sabique

    2016-12-01

    Wind and waves play a major role in important ocean dynamical processes, such as the exchange of heat, momentum and gases between atmosphere and ocean, that greatly contributes to the earth climate and marine lives. Knowledge on wind and wave weather and climate is crucial for a wide range of applications, including oceanographic studies, maritime activities and ocean engineering. Despite being one of the important world shipping routes, the wind-wave characteristics in the Red Sea are yet to be fully explored. Because of the scarcity of waves data in the Red Sea, numerical models become crucial and provide very powerful tools to extrapolate wind and wave data in space, and backward and forward in time. Unlike open oceans, enclosed basins wave have different characteristics, mainly because of their local generation processes. The complex orography on both sides of the Red Sea makes the local wind, and consequently wave, modeling very challenging. This thesis considers the modeling of wind-wave characteristics in the Red Sea, including their climate variability and trends using state-of-the-art numerical models and all available observations. Different approaches are investigated to model and understand the general and unusual wind and wave conditions in the basin using standard global meteorological products and customised regional wind and wave models. After studying and identifying the main characteristics of the wind-wave variability in the Red Sea, we demonstrate the importance of generating accurate atmospheric forcing through data assimilation for reliable wave simulations. In particular, we show that the state-of-the-art physical formulation of wave models is not suitable to model the unique situation of the two opposing wind-waves systems in the Red Sea Convergence Zone, and propose and successfully test a modification to the input and white-capping source functions to address this problem. We further investigate the climate variability and trends of wind

  7. Nuclear power

    International Nuclear Information System (INIS)

    King, P.

    1990-01-01

    Written from the basis of neutrality, neither for nor against nuclear power this book considers whether there are special features of nuclear power which mean that its development should be either promoted or restrained by the State. The author makes it dear that there are no easy answers to the questions raised by the intervention of nuclear power but calls for openness in the nuclear decision making process. First, the need for energy is considered; most people agree that energy is the power to progress. Then the historicalzed background to the current position of nuclear power is given. Further chapters consider the fuel cycle, environmental impacts including carbon dioxide emission and the greenhouse effect, the costs, safety and risks and waste disposal. No conclusion either for or against nuclear power is made. The various shades of opinion are outlined and the arguments presented so that readers can come to their own conclusions. (UK)

  8. Climatology of the autumn Red Sea trough

    Science.gov (United States)

    Awad, Adel M.; Mashat, Abdul-Wahab S.

    2018-03-01

    In this study, the Sudan low and the associated Red Sea trough (RST) are objectively identified using the mean sea level pressure (SLP) data from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis dataset covering the period 1955-2015. The Sudan low was detected in approximately 60.6% of the autumn periods, and approximately 83% of the detected low-pressure systems extended into RSTs, with most generated at night and during cold months. The distribution of the RSTs demonstrated that Sudan, South Sudan and Red Sea are the primary development areas of the RSTs, generating 97% of the RSTs in the study period. In addition, the outermost areas affected by RSTs, which include the southern, central and northern Red Sea areas, received approximately 91% of the RSTs originating from the primary generation areas. The synoptic features indicated that a Sudan low developed into an RST when the Sudan low deepened in the atmosphere, while the low pressures over the southern Arabian Peninsula are shallow and the anticyclonic systems are weakened over the northern Red Sea. Moreover, stabile areas over Africa and Arabian Peninsula form a high stability gradient around the Red Sea and the upper maximum winds weaken. The results of the case studies indicate that RSTs extend northward when the upper cyclonic and anticyclonic systems form a high geopotential gradient over Arabian Peninsula. Furthermore, the RST is oriented from the west to the east when the Azores high extends eastward and the Siberian high shrinks eastward or shifts northward.

  9. Observations of the summer Red Sea circulation

    Science.gov (United States)

    Sofianos, Sarantis S.; Johns, William E.

    2007-06-01

    Aiming at exploring and understanding the summer circulation in the Red Sea, a cruise was conducted in the basin during the summer of 2001 involving hydrographic, meteorological, and direct current observations. The most prominent feature, characteristic of the summer circulation and exchange with the Indian Ocean, is a temperature, salinity, and oxygen minimum located around a depth of 75 m at the southern end of the basin, associated with Gulf of Aden Intermediate Water inflowing from the Gulf of Aden during the summer season as an intruding subsurface layer. Stirring and mixing with ambient waters lead to marked increases in temperature (from 16.5 to almost 33°C) and salinity (from 35.7 to more than 38 psu) in this layer by the time it reaches midbasin. The observed circulation presents a very vigorous pattern with strong variability and intense features that extend the width of the basin. A permanent cyclone, detected in the northern Red Sea, verifies previous observations and modeling studies, while in the central sector of the basin a series of very strong anticyclones were observed with maximum velocities exceeding 1 m/s. The three-layer flow pattern, representative of the summer exchange between the Red Sea and the Gulf of Aden, is observed in the strait of Bab el Mandeb. In the southern part of the basin the layer flow is characterized by strong banking of the inflows and outflows against the coasts. Both surface and intermediate water masses involved in the summer Red Sea circulation present prominent spatial variability in their characteristics, indicating that the eddy field and mixing processes play an important role in the summer Red Sea circulation.

  10. Glacial conditions in the Red Sea

    Science.gov (United States)

    Rohling, Eelco J.

    1994-10-01

    In this paper, results from previous studies on planktonic foraminifera, δ18O, and global sea level are combined to discuss climatic conditions in the Red Sea during the last glacial maximum (18,000 B.P.). First, the influence of 120-m sea level lowering on the exchange transport through the strait of Bab-el-Mandab is considered. This strait is the only natural connection of the Red Sea to the open ocean. Next, glacial Red Sea outflow salinity is estimated (about 48 parts per thousand) from the foraminiferal record. Combined, these results yield an estimate of the glacial net water deficit, which appears to have been quite similar to the present (about 2 m yr-1). Finally, budget calculation of δ18O fluxes suggests that the glacial δ18O value of evaporation was about 50% of the present value. This is considered to have resulted from substantially increased mean wind speeds over the glacial Red Sea, which would have caused a rapid drop in the kinematic fractionation factor for 18O. The sensitivity of the calculated values for water deficit and isotopic fractionation to the various assumptions and estimates is evaluated in the discussion. Improvents are to be expected especially through research on the glacial salinity contrast between the Red Sea and Gulf of Aden. It is argued, however, that such future improvement will likely result in a worsening of the isotopic discrepancy, thus increasing the need for an additional mechanism that influenced fractionation (such as mean wind speed). This study demonstrates the need for caution when calculating paleosalinities from δ18O records under the assumption that the modern S∶δ18O relation has remained constant through time. Previously overlooked factors, such as mean wind speed, may have significantly altered that relation in the past.

  11. Cyber Power

    Science.gov (United States)

    2010-05-01

    government. Another way of looking at power in the cyber domain is to consider the three faces or aspects of relational power. 1st Face: (A induces B do...power. For example, on the February 2010 anniversary of the Iranian Revolution, the government slowed the internet to prevent protesters sending films ...all but a few government controlled Web sites. The damage to business and tourism was significant, but the Chinese government was more concerned

  12. Star power

    International Nuclear Information System (INIS)

    Kennedy, Tom

    2003-01-01

    Discusses the fight over the diminishing supply of fossil fuels and how there could be an unlimited, clean and politically free source of power just over the horizon. Fusion was discovered as a much better, inexhaustable supply of power, it only takes a few atoms to fuse for fusion to take off. Fusion once started will continue until all the fuel is exhausted. It is expected, that with the current rate of progess, in fifty years time scientists will achieve practical fusion power

  13. Chernobyl and nuclear power in the USSR

    International Nuclear Information System (INIS)

    Marples, D.R.

    1987-01-01

    Drawing extensively upon Soviet newspapers and journals, Soviet television and radio reports, records in the Krasnyi Arkhib (Red Archive) and contacts with workers involved in the building of the Chernobyl plant, the author provides the first detailed account of the Soviet nuclear power industry and of the nature, impact and consequences of the Chernobyl accident of late April 1986. The author raises the key questions: are Soviet nuclear power plants inherently unsafe, and what impact will the Chernobyl accident have on the Soviet nuclear energy program and on nuclear power development throughout the world?

  14. A review of elasmobranch research in the Red Sea

    KAUST Repository

    Spaet, Julia L.Y.; Thorrold, Simon R.; Berumen, Michael L.

    2012-01-01

    Given the global concern about the status of elasmobranch fishes, the paucity of information on elasmobranchs in the Red Sea is worrisome. Management of elasmobranchs in areas other than the Red Sea has been helped by research on population ecology

  15. Food composition and feeding ecology of the Red Fox Vulpes ...

    African Journals Online (AJOL)

    Food composition of the Red Fox Vulpes vulpes populations in different habitats in Egypt is ..... The dietary choices of small carnivores such as the Red Fox will depend primarily ... Similarly, feeding on carrion would be most cost effective. The.

  16. Red Rock Canyon National Conservation Area Transportation Feasibility Study

    Science.gov (United States)

    2012-07-31

    Red Rock Canyon National Conservation Area is a popular Bureau of Land Management natural area located near Las Vegas, Nevada. Red Rock Canyon experiences heavy congestion on its Scenic Drive and associated parking areas, due to high volumes of visit...

  17. Studies on cytotoxicity and antitumor screening of red and white ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-11-19

    Nov 19, 2008 ... 2Department of Botany, Government Arts College (Autonomous), Salem – 636 007, Tamilnadu, India. ... namely red and black coloured seeds (red form) and the ... development induced by Dalton's Lymphoma Ascites.

  18. Bioavailability and Biokinetics of Anthocyanins From Red Grape Juice and Red Wine

    Directory of Open Access Journals (Sweden)

    Roland Bitsch

    2004-01-01

    Full Text Available In a comparative study, 9 healthy volunteers ingested a single oral dose of 400 mL red grape juice or red wine with dose-adjusted anthocyanin content (283.5 mg or 279.6 mg, resp. in crossover. The content of anthocyanin glucosides was detected in plasma and urinary excretion. Additionally, the plasmatic antioxidant activity was assessed after intake. Based on the plasma content, biokinetic criteria of the single anthocyanins were calculated, such as AUC, cmax, tmax, and the elimination rate t1/2. The urinary excretion of total anthocyanins differed significantly and amounted to 0.18% (red wine and 0.23% (red grape juice of the administered dose. Additionally, the plasmatic antioxidant activity increased to higher levels after juice ingestion compared to wine. The intestinal absorption of the anthocyanins of red grape juice seemed to be improved compared to red wine, suggesting a possible synergistic effect of the glucose content of the juice. The improved absorption resulted in an enhanced plasmatic bioactivity.

  19. Growth and replication of red rain cells at 121°C and their red fluorescence

    Science.gov (United States)

    Gangappa, Rajkumar; Wickramasinghe, Chandra; Wainwright, Milton; Kumar, A. Santhosh; Louis, Godfrey

    2010-09-01

    We have shown that the red cells found in the Red Rain (which fell on Kerala, India, in 2001) survive and grow after incubation for periods of up to two hours at 121°C . Under these conditions daughter cells appear within the original mother cells and the number of cells in the samples increases with length of exposure to 121°C. No such increase in cells occurs at room temperature, suggesting that the increase in daughter cells is brought about by exposure of the Red Rain cells to high temperatures. This is an independent confirmation of results reported earlier by two of the present authors, claiming that the cells can replicate under high pressure at temperatures upto 300°C. The flourescence behaviour of the red cells is shown to be in remarkable correspondence with the extended red emission observed in the Red Rectagle planetary nebula and other galactic and extragalactic dust clouds, suggesting, though not proving an extraterrestrial origin.

  20. Seeing Red: Inside the Science and Politics of the IUCN Red List

    Directory of Open Access Journals (Sweden)

    Lisa M Campbell

    2012-01-01

    Full Text Available The Red List of Threatened Species™ (hereafter Red List is the International Union for the Conservation of Nature′s most recognisable product. The Red List categorises the conservation status of species on a global scale using ′the most objective, scientifically-based information′. Completing Red List assessments is the job of the Species Survival Commission (SSC, and assessments are most often conducted by species specialist groups within the SSC. In the SSC′s Marine Turtle Specialist Group (MTSG, assessments have been contested. Debate is often couched in scientific terms, focused on data availability and the relevance of Red List criteria for marine turtles. However, given the potential conservation impacts of such listings, much more is at stake. In this paper, I analyse an exchange among MTSG members that resulted when the draft Red List assessment for the hawksbill sea turtle was circulated to the group in June 2007. The suggested listing of hawksbill turtles as ′critically endangered′ sparked an email exchange that highlighted not only the scientific, but also the political, economic, and value-based dimensions of the debate. I draw on ideas of co-production and boundary work to analyse both the debate and the MTSG′s response to an associated crisis of legitimacy, and to provide insights into the science-policy interface in conservation.

  1. The effects of Red Bull energy drink compared with caffeine on cycling time-trial performance.

    Science.gov (United States)

    Quinlivan, Alannah; Irwin, Christopher; Grant, Gary D; Anoopkumar-Dukie, Sheilandra; Skinner, Tina; Leveritt, Michael; Desbrow, Ben

    2015-10-01

    This study investigated the ergogenic effects of a commercial energy drink (Red Bull) or an equivalent dose of anhydrous caffeine in comparison with a noncaffeinated control beverage on cycling performance. Eleven trained male cyclists (31.7 ± 5.9 y 82.3 ± 6.1 kg, VO2max = 60.3 ± 7.8 mL · kg-1 · min-1) participated in a double-blind, placebo-controlled, crossover-design study involving 3 experimental conditions. Participants were randomly administered Red Bull (9.4 mL/kg body mass [BM] containing 3 mg/kg BM caffeine), anhydrous caffeine (3 mg/kg BM given in capsule form), or a placebo 90 min before commencing a time trial equivalent to 1 h cycling at 75% peak power output. Carbohydrate and fluid volumes were matched across all trials. Performance improved by 109 ± 153 s (2.8%, P = .039) after Red Bull compared with placebo and by 120 ± 172 s (3.1%, P = .043) after caffeine compared with placebo. No significant difference (P > .05) in performance time was detected between Red Bull and caffeine treatments. There was no significant difference (P > .05) in mean heart rate or rating of perceived exertion among the 3 treatments. This study demonstrated that a moderate dose of caffeine consumed as either Red Bull or in anhydrous form enhanced cycling time-trial performance. The ergogenic benefits of Red Bull energy drink are therefore most likely due to the effects of caffeine, with the other ingredients not likely to offer additional benefit.

  2. Physical and Chemical Properties of Sintering Red Mud and Bayer Red Mud and the Implications for Beneficial Utilization

    Science.gov (United States)

    Wang, Ping; Liu, Dong-Yan

    2012-01-01

    Performances of two common types of red mud, Bayer red mud and Sintering red mud, were investigated in this research. Their compositions, mechanical properties and microstructure characterization were measured through XRD, TG and SEM analysis. Their shear strength, particle size, density and hydraulic characteristics also had been performed. Huge differences between the basic mineral types of these two kinds of red mud also can be found. The comparison of compositions shows that CaCO3 content in Sintering red mud is higher, Bayer red mud has more hazardous elements such as As, Pb and Hg and both have a high concentration of radioactivity. The micro particle of Bayer red mud is finer and more disperse, but the Sintering red mud has higher shear strength. Combining the TG and hydraulic characteristics analysis, it can be shown that Bayer red mud has higher value of water content and Sintering red mud has higher hydraulic conductivity. The paper then illustrates that Sintering red mud can become the main filling material of supporting structure of red mud stocking yard. Bayer red mud has a high reuse value and also can be used as a mixing material of masonry mortar.

  3. Comparative Study of Betacyanin Profile and Antimicrobial Activity of Red Pitahaya (Hylocereus polyrhizus) and Red Spinach (Amaranthus dubius).

    Science.gov (United States)

    Yong, Yi Yi; Dykes, Gary; Lee, Sui Mae; Choo, Wee Sim

    2017-03-01

    Betacyanins are reddish to violet pigments that can be found in red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius). This study investigated the impact of sub-fractionation (solvent partitioning) on betacyanin content in both plants. Characterization of betacyanins and evaluation of their antimicrobial activities were also carried out. Betanin was found in both plants. In addition, isobetanin, phyllocactin and hylocerenin were found in red pitahaya whereas amaranthine and decarboxy-amaranthine were found in red spinach. Sub-fractionated red pitahaya and red spinach had 23.5 and 121.5 % more betacyanin content, respectively, than those without sub-fractionation. Sub-fractionation increased the betanin and decarboxy-amaranthine content in red pitahaya and red spinach, respectively. The betacyanin fraction from red spinach (minimum inhibitory concentration [MIC] values: 0.78-3.13 mg/mL) demonstrated a better antimicrobial activity profile than that of red pitahaya (MIC values: 3.13-6.25 mg/mL) against nine Gram-positive bacterial strains. Similarly, the red spinach fraction (MIC values: 1.56-3.13 mg/mL) was more active than the red pitahaya fraction (MIC values: 3.13-6.25 mg/mL) against five Gram-negative bacterial strains. This could be because of a higher amount of betacyanin, particularly amaranthine in the red spinach.

  4. Seasonal variation in the structure of red reflectance of leaves from yellow poplar, red oak, and red maple

    Science.gov (United States)

    Brakke, Thomas W.; Wergin, William P.; Erbe, Eric F.; Harnden, Joann M.

    1993-01-01

    The light scattered from leaves was measured as a function of view angle in the principal plane for yellow poplar, red oak, and red maple. The source was a parallel-polarized helium-neon laser. Yellow poplar leaves had the highest reflectance of the three species, which may have been due to its shorter palisade cells and more extensive spongy mesophyll. Prior to senescence, there was a significant decrease, but not total extinction, in the reflectance of the beam incident at 60 deg from nadir on the adaxial side of the leaves of all three species. Low-temperature SEM observations showed differences in the surface wax patterns among the three species but did not indicate a cause of the reflectance changes other than possibly the accumulation and aging of the wax.

  5. Diseño de una red WAN

    OpenAIRE

    Labella Sanz, Gabriel

    2010-01-01

    Disseny d'una xarxa WAN, formada per una xarxa d'Accés HFC, una xarxa de Commutació ATM i una xarxa de Transport SDH. Diseño de una red WAN, formada por una red de Acceso HFC, una red de Conmutación ATM y una red de Transporte SDH. WAN network design consisting of a HFC access network, an ATM switching network and a SDH transport network.

  6. Experience Reverses the Red Effect among Chinese Stockbrokers

    OpenAIRE

    Zhang, Tengxiao; Han, Buxin

    2014-01-01

    Recent research has shown that the color red influences psychological functioning. Red is hypothesized to be linked to aggression and danger in evolution, and these links are enhanced by culture-specific uses of red. Thus, color meanings are thought to be grounded in biologically based proclivities and learned associations. However, to date, there has been no direct evidence for the influence of experience on the red effect. This study focused on whether experience could change the psychologi...

  7. Far red bioluminescence from two deep-sea fishes.

    Science.gov (United States)

    Widder, E A; Latz, M I; Herring, P J; Case, J F

    1984-08-03

    Spectral measurements of red bioluminescence were obtained from the deep-sea stomiatoid fishes Aristostomias scintillans (Gilbert) and Malacosteus niger (Ayres). Red luminescence from suborbital light organs extends to the near infrared, with peak emission at approximately 705 nanometers in the far red. These fishes also have postorbital light organs that emit blue luminescence with maxima between 470 and 480 nanometers. The red bioluminescence may be due to an energy transfer system and wavelength-selective filtering.

  8. Power Talk

    DEFF Research Database (Denmark)

    Liu, Hongpeng; Yang, Yongheng; Loh, Poh Chiang

    2016-01-01

    In this paper, a novel communication strategy called Power Talk is introduced to realize the power line communication among the Voltage Source Converters (VSC) of DC MicroGrids (MGs). Each VSC transmits information by changing the control parameters, and receives information by observing the local...

  9. Power Talk

    DEFF Research Database (Denmark)

    Stefanovic, Cedomir; Popovski, Petar; Angjelichinoski, Marko

    2015-01-01

    We introduce a novel communication strategy for DC Micro Grids (MGs), termed power talk, in which the devices communicate by modulating the power levels in the DC bus. The information is transmitted by varying the parameters that the MG units use to control the level of the common bus voltage...

  10. Nuclear power

    International Nuclear Information System (INIS)

    Abd Khalik Wood

    2003-01-01

    This chapter discuss on nuclear power and its advantages. The concept of nucleus fission, fusion, electric generation are discussed in this chapter. Nuclear power has big potential to become alternative energy to substitute current conventional energy from coal, oil and gas

  11. Power Electronics

    Indian Academy of Sciences (India)

    Such real time models are extremely important, as they can be included in real time simulation of sys- tems to evolve control schemes for the converters as well as to study the effect on the power system. In view of the control possibilities offered by the use of power converters and the newly emerging applications, there has ...

  12. Powering Mexico

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This article examines Mexico's demand for electricity and the market for independent power generation. The topics discussed in the article include the outlook for the 1990s for growth in Mexico's economy and energy demand, renewable energy, energy conservation, small-scale, off-grid renewable energy systems, and estimates of Mexico's market for electric power generating equipment

  13. Pulsed power

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The key element of our pulsed power program is concentration of power in time and space by suppression of breakdown in dielectrics and in vacuum. Magnetically insulated vacuum transmission lines and magnetic suppression of insulator flashover have continued as the main reserch directions. Vacuum insulated line studies at Physics International have been expanded and a test bed at Sandia, called MITE (Magnetically Insulated Transmission Experiment), is under development. The choice for the baseline EBFA design will depend on the outcome of these studies and should be made in July 1977. The slow and intermediate speed pulsed power approaches to EBFA will be based on Proto I and Proto II results and several of the projected EBFA subsystems are presently being tested in Proto II. A further stage of power concentration, within the vacuum diode itself, would considerably ease the burden on dielectrics; methods of power multiplication involving magnetically imploded plasmas are being considered and tests have begun using the Ripple III apparatus

  14. Maxillofacial and mandibular phenotypes in the skulls of red Sokoto ...

    African Journals Online (AJOL)

    This work examined phenotypic expressions in the anatomy of the mandible and maxillofacial region of the Red Sokoto and Sahel goats in Nigeria. The infraorbital foramen was placed above premolar two (PM2) in Red Sokoto but above premolar one (PM1) in Sahel. The Red Sokoto displayed interdigital septa (ruggae) ...

  15. EST data - RED | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available switchLanguage; BLAST Search Image Search Home About Archive Update History Data ...st.zip File URL: ftp://ftp.biosciencedbc.jp/archive/red/LATEST/red_est.zip File size: 629 KB Simple search U...ase Database Description Download License Update History of This Database Site Policy | Contact Us EST data - RED | LSDB Archive ...

  16. 7 CFR 29.3052 - Red color (R).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Red color (R). 29.3052 Section 29.3052 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Red color (R). A brownish red. [24 FR 8771, Oct. 29, 1959. Redesignated at 47 FR 51722, Nov. 17, 1982...

  17. 7 CFR 29.3068 - Tannish-red color (FR).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Tannish-red color (FR). 29.3068 Section 29.3068 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Type 93) § 29.3068 Tannish-red color (FR). A light red shaded toward tan. [24 FR 8771, Oct. 29, 1959...

  18. 7 CFR 29.1044 - Orange Red (FR).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Orange Red (FR). 29.1044 Section 29.1044 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1044 Orange Red (FR). A yellowish red. [42 FR 21092, Apr. 25, 1977. Redesignated at 47 FR...

  19. 21 CFR 660.30 - Reagent Red Blood Cells.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Reagent Red Blood Cells. 660.30 Section 660.30...) BIOLOGICS ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Reagent Red Blood Cells § 660.30 Reagent Red Blood Cells. (a) Proper name and definition. The proper name of the product shall be...

  20. Hidden values in bauxite residue (red mud): Recovery of metals

    International Nuclear Information System (INIS)

    Liu, Yanju; Naidu, Ravi

    2014-01-01

    Highlights: • Current iron recovery techniques using red mud are depicted. • Advantages and disadvantages exist in different recovering processes. • Economic and environmental friendly integrated usage of red mud is promising. - Abstract: Bauxite residue (red mud) is a hazardous waste generated from alumina refining industries. Unless managed properly, red mud poses significant risks to the local environment due to its extreme alkalinity and its potential impacts on surface and ground water quality. The ever-increasing generation of red mud poses significant challenges to the aluminium industries from management perspectives given the low proportion that are currently being utilized beneficially. Red mud, in most cases, contains elevated concentrations of iron in addition to aluminium, titanium, sodium and valuable rare earth elements. Given the scarcity of iron supply globally, the iron content of red mud has attracted increasing research interest. This paper presents a critical overview of the current techniques employed for iron recovery from red mud. Information on the recovery of other valuable metals is also reviewed to provide an insight into the full potential usage of red mud as an economic resource rather than a waste. Traditional hydrometallurgy and pyrometallurgy are being investigated continuously. However, in this review several new techniques are introduced that consider the process of iron recovery from red mud. An integrated process which can achieve multiple additional values from red mud is much preferred over the single process methods. The information provided here should help to improve the future management and utilization of red mud

  1. Hidden values in bauxite residue (red mud): Recovery of metals

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yanju; Naidu, Ravi, E-mail: ravi.naidu@unisa.edu.au

    2014-12-15

    Highlights: • Current iron recovery techniques using red mud are depicted. • Advantages and disadvantages exist in different recovering processes. • Economic and environmental friendly integrated usage of red mud is promising. - Abstract: Bauxite residue (red mud) is a hazardous waste generated from alumina refining industries. Unless managed properly, red mud poses significant risks to the local environment due to its extreme alkalinity and its potential impacts on surface and ground water quality. The ever-increasing generation of red mud poses significant challenges to the aluminium industries from management perspectives given the low proportion that are currently being utilized beneficially. Red mud, in most cases, contains elevated concentrations of iron in addition to aluminium, titanium, sodium and valuable rare earth elements. Given the scarcity of iron supply globally, the iron content of red mud has attracted increasing research interest. This paper presents a critical overview of the current techniques employed for iron recovery from red mud. Information on the recovery of other valuable metals is also reviewed to provide an insight into the full potential usage of red mud as an economic resource rather than a waste. Traditional hydrometallurgy and pyrometallurgy are being investigated continuously. However, in this review several new techniques are introduced that consider the process of iron recovery from red mud. An integrated process which can achieve multiple additional values from red mud is much preferred over the single process methods. The information provided here should help to improve the future management and utilization of red mud.

  2. Zonal surface wind jets across the Red Sea due to mountain gap forcing along both sides of the Red Sea

    KAUST Repository

    Jiang, Houshuo; Farrar, J. Thomas; Beardsley, Robert C.; Chen, Ru; Chen, Changsheng

    2009-01-01

    [1] Mesoscale atmospheric modeling over the Red Sea, validated by in-situ meteorological buoy data, identifies two types of coastal mountain gap wind jets that frequently blow across the longitudinal axis of the Red Sea: (1) an eastward

  3. Flaring red dwarf stars: news from Crimea

    International Nuclear Information System (INIS)

    Gershberg, Roald E

    1998-01-01

    Important phenomena are briefly described which have recently been discovered in the Crimean studies of flaring red dwarf stars believed to be the most common type of variable stars in the Galaxy. These phenomena include (i) long-lived radiation from a blueshifted component in the ionized-helium λ 4686 A emission line in the active state of one such star, (ii) a long-lived absorption component in the stellar flare light curves with a lifetime exceeding that of the conventional flare emission, and (iii) solarcycle-like activity periodicity of the star EV Lac, whose mass is only 0.3 solar masses. In theoretical terms, a red dwarf star spot model is constructed which, in contrast to the commonly accepted model, agrees well with the solar spot picture. (physics of our days)

  4. Flaring red dwarf stars: news from Crimea

    Energy Technology Data Exchange (ETDEWEB)

    Gershberg, Roald E [Crimean Astrophysical Observatory, Nauchnyi, Crimea (Ukraine)

    1998-08-31

    Important phenomena are briefly described which have recently been discovered in the Crimean studies of flaring red dwarf stars believed to be the most common type of variable stars in the Galaxy. These phenomena include (i) long-lived radiation from a blueshifted component in the ionized-helium {lambda} 4686 A emission line in the active state of one such star, (ii) a long-lived absorption component in the stellar flare light curves with a lifetime exceeding that of the conventional flare emission, and (iii) solarcycle-like activity periodicity of the star EV Lac, whose mass is only 0.3 solar masses. In theoretical terms, a red dwarf star spot model is constructed which, in contrast to the commonly accepted model, agrees well with the solar spot picture. (physics of our days)

  5. Molecular biodiversity of Red Sea demosponges.

    Science.gov (United States)

    Erpenbeck, Dirk; Voigt, Oliver; Al-Aidaroos, Ali M; Berumen, Michael L; Büttner, Gabriele; Catania, Daniela; Guirguis, Adel Naguib; Paulay, Gustav; Schätzle, Simone; Wörheide, Gert

    2016-04-30

    Sponges are important constituents of coral reef ecosystems, including those around the Arabian Peninsula. Despite their importance, our knowledge on demosponge diversity in this area is insufficient to recognize, for example, faunal changes caused by anthropogenic disturbances. We here report the first assessment of demosponge molecular biodiversity from Arabia, with focus on the Saudi Arabian Red Sea, based on mitochondrial and nuclear ribosomal molecular markers gathered in the framework of the Sponge Barcoding Project. We use a rapid molecular screening approach on Arabian demosponge collections and analyze results in comparison against published material in terms of biodiversity. We use a variable region of 28S rDNA, applied for the first time in the assessment of demosponge molecular diversity. Our data constitutes a solid foundation for a future more comprehensive understanding of sponge biodiversity of the Red Sea and adjacent waters. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Red wine: A drink to your heart

    Science.gov (United States)

    Saleem, T.S. Mohamed; Basha, S. Darbar

    2010-01-01

    Mortality and morbidity are still high in cardiovascular disease (CVD). Myocardial ischemia reperfusion injury leading to myocardial infarction is one of the most frequent causes of the death in humans. Atherosclerosis and generation of reactive oxygen species through oxidative stress is the major risk factor for CVD. From the literature collection, it has been identified that moderate consumption of red wine helps in preventing CVD through several mechanisms, including increasing the high-density lipoprotein cholesterol plasma levels, decreasing platelet aggregation, by antioxidant effects, and by restoration of endothelial function. The aim of this review is to discuss the accumulating evidence that suggests that red wine possesses a diverse range of biological actions and may be beneficial in the prevention of CVD. PMID:21264180

  7. Molecular biodiversity of Red Sea demosponges

    KAUST Repository

    Erpenbeck, Dirk; Voigt, Oliver; Al-Aidaroos, Ali M.; Berumen, Michael L.; Bü ttner, Gabriele; Catania, Daniela; Guirguis, Adel Naguib; Paulay, Gustav; Schä tzle, Simone; Wö rheide, Gert

    2016-01-01

    Sponges are important constituents of coral reef ecosystems, including those around the Arabian Peninsula. Despite their importance, our knowledge on demosponge diversity in this area is insufficient to recognize, for example, faunal changes caused by anthropogenic disturbances. We here report the first assessment of demosponge molecular biodiversity from Arabia, with focus on the Saudi Arabian Red Sea, based on mitochondrial and nuclear ribosomal molecular markers gathered in the framework of the Sponge Barcoding Project. We use a rapid molecular screening approach on Arabian demosponge collections and analyze results in comparison against published material in terms of biodiversity. We use a variable region of 28S rDNA, applied for the first time in the assessment of demosponge molecular diversity. Our data constitutes a solid foundation for a future more comprehensive understanding of sponge biodiversity of the Red Sea and adjacent waters.

  8. Molecular biodiversity of Red Sea demosponges

    KAUST Repository

    Erpenbeck, Dirk

    2016-01-07

    Sponges are important constituents of coral reef ecosystems, including those around the Arabian Peninsula. Despite their importance, our knowledge on demosponge diversity in this area is insufficient to recognize, for example, faunal changes caused by anthropogenic disturbances. We here report the first assessment of demosponge molecular biodiversity from Arabia, with focus on the Saudi Arabian Red Sea, based on mitochondrial and nuclear ribosomal molecular markers gathered in the framework of the Sponge Barcoding Project. We use a rapid molecular screening approach on Arabian demosponge collections and analyze results in comparison against published material in terms of biodiversity. We use a variable region of 28S rDNA, applied for the first time in the assessment of demosponge molecular diversity. Our data constitutes a solid foundation for a future more comprehensive understanding of sponge biodiversity of the Red Sea and adjacent waters.

  9. Improvements to the Red List Index.

    Directory of Open Access Journals (Sweden)

    Stuart H M Butchart

    Full Text Available The Red List Index uses information from the IUCN Red List to track trends in the projected overall extinction risk of sets of species. It has been widely recognised as an important component of the suite of indicators needed to measure progress towards the international target of significantly reducing the rate of biodiversity loss by 2010. However, further application of the RLI (to non-avian taxa in particular has revealed some shortcomings in the original formula and approach: It performs inappropriately when a value of zero is reached; RLI values are affected by the frequency of assessments; and newly evaluated species may introduce bias. Here we propose a revision to the formula, and recommend how it should be applied in order to overcome these shortcomings. Two additional advantages of the revisions are that assessment errors are not propagated through time, and the overall level extinction risk can be determined as well as trends in this over time.

  10. Mantle helium in the Red Sea brines

    International Nuclear Information System (INIS)

    Lupton, J.E.; Weiss, R.F.; Craig, H.

    1977-01-01

    It is stated that He isotope studies of terrestrial samples have shown the existence of two He components that are clearly distinct from atmospheric He. These are termed 'crustal' He and 'mantle' He; the latter was discovered as 'excess 3 He' in deep ocean water and attributed to a flux of primordial He from the mantle. Studies of the 3 He/ 4 He ratio in deep Pacific water and in He trapped in submarine basalt glasses showed that this 'mantle' component is characterised by ratios about ten times the atmospheric ratio and 100 times the ratio in 'crustal' He. Basalt glasses from other deep sea waters also showed similar ratios, and it is indicated that 'mantle' He in areas in which new lithosphere is being formed has a unique and uniform isotopic signature. Measurements of He and Ne are here reported that reveal additional information on the origin of Red Sea brines and their relationship to the Red Sea rifts. (U.K.)

  11. Nuclear power

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    The committee concludes that the nature of the proliferation problem is such that even stopping nuclear power completely could not stop proliferation completely. Countries can acquire nuclear weapons by means independent of commercial nuclear power. It is reasonable to suppose if a country is strongly motivated to acquire nuclear weapons, it will have them by 2010, or soon thereafter, no matter how nuclear power is managed in the meantime. Unilateral and international diplomatic measures to reduce the motivations that lead to proliferation should be high on the foreign policy agenda of the United States. A mimimum antiproliferation prescription for the management of nuclear power is to try to raise the political barriers against proliferation through misuse of nuclear power by strengthening the Non-Proliferation Treaty, and to seek to raise the technological barriers by placing fuel-cycle operations involving weapons-usable material under international control. Any such measures should be considered tactics to slow the spread of nuclear weapons and thus earn time for the exercise of statesmanship. The committee concludes the following about technical factors that should be considered in formulating nuclear policy: (1) rate of growth of electricity use is a primary factor; (2) growth of conventional nuclear power will be limited by producibility of domestic uranium sources; (3) greater contribution of nuclear power beyond 400 GWe past the year 2000 can only be supported by advanced reactor systems; and (4) several different breeder reactors could serve in principle as candidates for an indefinitely sustainable source of energy

  12. Power generation

    International Nuclear Information System (INIS)

    Nunez, Anibal D.

    2001-01-01

    In the second half of twentieth century, nuclear power became an industrial reality. Now the operating 433 power plants, the 37 plants under construction, near 9000 years/reactor with only one serious accident with emission of radioactive material to the environment (Chernobyl) show the maturity of this technology. Today nuclear power contribute a 17% to the global generation and an increase of 75 % of the demand of electricity is estimated for 2020 while this demand is expected to triplicate by 2050. How this requirement can be satisfied? All the indicators seems to demonstrate that nuclear power will be the solution because of the shortage of other sources, the increase of the prices of the non renewable fuels and the scarce contribution of the renewable ones. In addition, the climatic changes produced by the greenhouse effect make even more attractive nuclear power. The situation of Argentina is analyzed and compared with other countries. The convenience of an increase of nuclear power contribution to the total national generation seems clear and the conclusion of the construction of the Atucha II nuclear power plant is recommended

  13. [Red lip defects. Reconstructive techniques and indications].

    Science.gov (United States)

    Simon, E; Stricker, M; Duroure, F

    2002-10-01

    The attractive color of the red lip must be the object of very meticulous reconstruction in their form and pigmentation. This can be done only by using the buccal mucosa. The graf is less indicated. There are multiple local flaps that have been proposed using the same lip, the jugal mucosa and the tongue. The authors will show the principal procedures found in the literature.

  14. Red wine: A drink to your heart

    OpenAIRE

    Saleem, T.S. Mohamed; Basha, S. Darbar

    2010-01-01

    Mortality and morbidity are still high in cardiovascular disease (CVD). Myocardial ischemia reperfusion injury leading to myocardial infarction is one of the most frequent causes of the death in humans. Atherosclerosis and generation of reactive oxygen species through oxidative stress is the major risk factor for CVD. From the literature collection, it has been identified that moderate consumption of red wine helps in preventing CVD through several mechanisms, including increasing the high-de...

  15. Red Wine Polyphenols and Vascular Function

    OpenAIRE

    Botden, Ilse

    2012-01-01

    textabstractHippocrates, the father of modern medicine, said many centuries ago: “let food be your medicine.” Today, this quote still shows its value, amongst others by the !nding that red wine consumption attributes to a healthy life style, reducing the risk to develop cardiovascular diseases. Cardiovascular diseases are one of the leading causes of death in many economically developed countries as well as in emerging economies.1 It has become a global epidemic problem, with type 2 diabetes,...

  16. Quality Characteristics of Appalachian Red Oak Lumber

    Science.gov (United States)

    Janice K Wiedenbeck; Charles J. Gatchell; Elizabeth S. Walker

    1995-01-01

    Red oak lumber defect information derived from a well-constructed board data bank was analyzed. The potential utility of No. 1 Common and No. 2A Common lumber is indicated by the finding that 23 percent of the No. 1 Common boards and 35 percent of the No. 2A Common boards in the data bank contain clear-face cutting percentages that meet the minimum requirement for the...

  17. 1992 Data Bank for Red Oak Lumber

    Science.gov (United States)

    Charles J. Gatchell; Janice K. Wiedenbeck; Elizabeth S. Walker; Elizabeth S. Walker

    1992-01-01

    The 1992 Data Bank for Red Oak Lumber is a collection of fully described FAS, Selects, No. 1 Common, and No. 2A Common boards (a total of 1,578 at present). The data bank has two unique features to aid in sample selection. The first feature is the double grading of FAS, No. 1 Common, and No. 2A Common boards to reflect the surface area in grading cuttings when grading...

  18. Red junglefowl have individual body odors

    OpenAIRE

    Karlsson, Anna-Carin; Jensen, Per; Elgland, Mathias; Laur, Katriann; Fyrner, Timmy; Konradsson, Peter; Laska, Matthias

    2010-01-01

    Olfaction may play an important role in regulating bird behavior, and has been suggested to be involved in feather-pecking. We investigated possible differences in the body odors of red junglefowl females by using an automated olfactometer which assessed the ability of trained mice to discriminate between the odors of uropygial gland secretions (the main carrier of potential individual odors in chickens) of six feather-pecked and six non-pecked birds. All mice were clearly able to discriminat...

  19. Diseño de red WAN

    OpenAIRE

    Spadaro, Gustavo Fabián

    2012-01-01

    Diseño de una Red WAN, para un operador de nivel internacional, con cobertura mundial, para brindar servicios de VPN, internet para empresas. Disseny d'una Xarxa WAN, per a un operador de nivell internacional, amb cobertura mundial, per brindar serveis de VPN, internet per a empreses. WAN Network Design for an international operator with global coverage, to provide VPN services, Internet for companies.

  20. The Red Book and clinical practice.

    Science.gov (United States)

    Bygott, Catherine

    2012-09-01

    Jung's work is fundamentally an experience, not an idea. From this perspective, I attempt to bridge conference, consulting room and living psyche by considering the influence of the 'Red Book' on clinical practice through the subtle and imaginal. Jung's journey as a man broadens out to have relevance for women. His story is individual but its archetypal foundation finds parallel expression in analytic practice today. © 2012, The Society of Analytical Psychology.

  1. Formation and spreading of Red Sea Outflow Water in the Red Sea

    Science.gov (United States)

    Zhai, Ping; Bower, Amy S.; Smethie, William M.; Pratt, Larry J.

    2015-09-01

    Hydrographic data, chlorofluorocarbon-12 (CFC-12) and sulfur hexafluoride (SF6) measurements collected in March 2010 and September-October 2011 in the Red Sea, as well as an idealized numerical experiment are used to study the formation and spreading of Red Sea Outflow Water (RSOW) in the Red Sea. Analysis of inert tracers, potential vorticity distributions, and model results confirm that RSOW is formed through mixed-layer deepening caused by sea surface buoyancy loss in winter in the northern Red Sea and reveal more details on RSOW spreading rates, pathways, and vertical structure. The southward spreading of RSOW after its formation is identified as a layer with minimum potential vorticity and maximum CFC-12 and SF6. Ventilation ages of seawater within the RSOW layer, calculated from the partial pressure of SF6 (pSF6), range from 2 years in the northern Red Sea to 15 years at 17°N. The distribution of the tracer ages is in agreement with the model circulation field which shows a rapid transport of RSOW from its formation region to the southern Red Sea where there are longer circulation pathways and hence longer residence time due to basin wide eddies. The mean residence time of RSOW within the Red Sea estimated from the pSF6 age is 4.7 years. This time scale is very close to the mean transit time (4.8 years) for particles from the RSOW formation region to reach the exit at the Strait of Bab el Mandeb in the numerical experiment.

  2. The photovoltaic generators and the electric network; Los generadores fotovoltaicos y la red electrica

    Energy Technology Data Exchange (ETDEWEB)

    Arteaga Novoa, Oscar E.; Agredano Diaz, Jaime; Huacuz Villamar, Jorge M. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    The photovoltaic generators are analyzed as an option for the electricity supply. An analysis is made of the option that these systems be utilized in sites where it is difficult to extend the power lines an in sites where the electric service already exists, such as residences, commercial buildings, network support power stations, central power stations, all this in order that the photovoltaic systems interact with the electric network for the generation of part of the energy consumed in these sites. In order that the photovoltaic systems can be interconnected with the electric network it is required: energy quality, protection and safety of the systems and persons and normativity for the interconnection. Some of the national programs of countries like Japan, United States of America and some organs of the Commission of the European Community are described. In conclusion, it is expected that the costs of this technology decrease so these systems can be widely utilized [Espanol] Se analizan los generadores fotovoltaicos como una alternativa para el suministro electrico. Se analiza la opcion de que estos sistemas se utilicen en lugares en donde es dificil extender la red electrica y en sitios en donde el servicio electrico ya existe, tales como: residencias, edificios comerciales, estaciones de apoyo a la red, estaciones centrales, esto con la finalidad de que el sistema fotovoltaico interactue con la red electrica a fin de generar parte de la energia que se consume en estos sitios. Para que los sistemas fotovoltaicos puedan estar interconectados con la red electrica se requiere: calidad de la energia, proteccion y seguridad de los sistemas y personas, y normatividad para la interconexion. Se describen algunos programas nacionales de paises como Japon, Estados Unidos y algunos organismos de la Comision de Comunidades Europeas. En conclusion, se espera que los costos de esta tecnologia disminuyan para que estos sistemas puedan ser ampliamante utilizados

  3. The photovoltaic generators and the electric network; Los generadores fotovoltaicos y la red electrica

    Energy Technology Data Exchange (ETDEWEB)

    Arteaga Novoa, Oscar E; Agredano Diaz, Jaime; Huacuz Villamar, Jorge M [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1998-12-31

    The photovoltaic generators are analyzed as an option for the electricity supply. An analysis is made of the option that these systems be utilized in sites where it is difficult to extend the power lines an in sites where the electric service already exists, such as residences, commercial buildings, network support power stations, central power stations, all this in order that the photovoltaic systems interact with the electric network for the generation of part of the energy consumed in these sites. In order that the photovoltaic systems can be interconnected with the electric network it is required: energy quality, protection and safety of the systems and persons and normativity for the interconnection. Some of the national programs of countries like Japan, United States of America and some organs of the Commission of the European Community are described. In conclusion, it is expected that the costs of this technology decrease so these systems can be widely utilized [Espanol] Se analizan los generadores fotovoltaicos como una alternativa para el suministro electrico. Se analiza la opcion de que estos sistemas se utilicen en lugares en donde es dificil extender la red electrica y en sitios en donde el servicio electrico ya existe, tales como: residencias, edificios comerciales, estaciones de apoyo a la red, estaciones centrales, esto con la finalidad de que el sistema fotovoltaico interactue con la red electrica a fin de generar parte de la energia que se consume en estos sitios. Para que los sistemas fotovoltaicos puedan estar interconectados con la red electrica se requiere: calidad de la energia, proteccion y seguridad de los sistemas y personas, y normatividad para la interconexion. Se describen algunos programas nacionales de paises como Japon, Estados Unidos y algunos organismos de la Comision de Comunidades Europeas. En conclusion, se espera que los costos de esta tecnologia disminuyan para que estos sistemas puedan ser ampliamante utilizados

  4. Molecular biodiversity of Red Sea demosponges

    International Nuclear Information System (INIS)

    Erpenbeck, Dirk; Voigt, Oliver; Al-Aidaroos, Ali M.; Berumen, Michael L.; Büttner, Gabriele; Catania, Daniela; Guirguis, Adel Naguib; Paulay, Gustav; Schätzle, Simone

    2016-01-01

    Sponges are important constituents of coral reef ecosystems, including those around the Arabian Peninsula. Despite their importance, our knowledge on demosponge diversity in this area is insufficient to recognize, for example, faunal changes caused by anthropogenic disturbances. We here report the first assessment of demosponge molecular biodiversity from Arabia, with focus on the Saudi Arabian Red Sea, based on mitochondrial and nuclear ribosomal molecular markers gathered in the framework of the Sponge Barcoding Project. We use a rapid molecular screening approach on Arabian demosponge collections and analyze results in comparison against published material in terms of biodiversity. We use a variable region of 28S rDNA, applied for the first time in the assessment of demosponge molecular diversity. Our data constitutes a solid foundation for a future more comprehensive understanding of sponge biodiversity of the Red Sea and adjacent waters. - Highlights: •First assessment of demosponge molecular biodiversity from Arabia •Rapid molecular screening approach on Arabian demosponge collections •Assessment of 28S 'C-Region' for demosponge barcoding •Data for a future comprehensive understanding of sponge biodiversity of the Red Sea

  5. Alcohol, red wine and cardiovascular disease.

    Science.gov (United States)

    Wollin, S D; Jones, P J

    2001-05-01

    The objective of this article is to review the existing literature concerning the effects and mechanisms of action of red wine consumption vs. other alcoholic beverages on the risk of cardiovascular disease (CVD). Of particular interest is the form and quantity of alcohol consumed. This relationship between alcohol consumption and mortality is well supported by epidemiologic studies, which have suggested that different forms of alcohol alter the relative risk values for mortality from CVD. Although not without exception, current evidence from epidemiologic and experimental studies suggests a protective effect against the development of CVD with moderate consumption of red wine. The exact nature of the protective effect remains to be established. However, mechanisms including LDL oxidation and alterations in hemostatic variables are being increasingly recognized as contributory. Key components of red wine thought to be responsible for the protective effects include phenolic compounds and alcohol content. Despite the research presented, some questions relating to the current recommendations regarding moderate alcohol consumption and cardiovascular health remain. However, collectively, the literature aids in understanding some of the ways in which alcoholic beverages and their components affect the health of our population.

  6. Red Sea as a source for bioprospecting

    KAUST Repository

    Kodzius, Rimantas

    2015-12-12

    King-Abdullah University of Science and Technology (KAUST) is located on the shores of the Red Sea in Saudi Arabia. The Red Sea is well known for its unique environment, harboring various microbes capable of surviving in salty brines. We collected sediment samples from brine pool adjacent to the Thuwal cold seeps in the Red Sea. The taxonomic analysis showed the diversity and abundance of bacterial and archaeal operational taxonomic units (OUT). Recently we established in the laboratory a microdroplet technology to encapsulate single cells. This technology enables us to analyze single-cell genomes and perform the high-throughput screening. The genomes of both cultivable and uncultivable organisms can be analyzed. We envision the collection of complimentary data, obtained by various techniques, such as single-cell genomics, metagenomics, and transcriptomics. That will enable us not only to understand the environment and microorganism communities but also will allow to discover the previously unknown genes, pathways, and whole genomes. These data will facilitate the enhancement of biological and chemical producers, and pave the way for bioprospecting.

  7. Abrupt warming of the Red Sea

    KAUST Repository

    Raitsos, D. E.

    2011-07-19

    Coral reef ecosystems, often referred to as “marine rainforests,” concentrate the most diverse life in the oceans. Red Sea reef dwellers are adapted in a very warm environment, fact that makes them vulnerable to further and rapid warming. The detection and understanding of abrupt temperature changes is an important task, as ecosystems have more chances to adapt in a slowly rather than in a rapid changing environment. Using satellite derived sea surface and ground based air temperatures, it is shown that the Red Sea is going through an intense warming initiated in the mid-90s, with evidence for an abrupt increase after 1994 (0.7°C difference pre and post the shift). The air temperature is found to be a key parameter that influences the Red Sea marine temperature. The comparisons with Northern Hemisphere temperatures revealed that the observed warming is part of global climate change trends. The hitherto results also raise additional questions regarding other broader climatic impacts over the area.

  8. Red junglefowl have individual body odors.

    Science.gov (United States)

    Karlsson, Anna-Carin; Jensen, Per; Elgland, Mathias; Laur, Katriann; Fyrner, Timmy; Konradsson, Peter; Laska, Matthias

    2010-05-01

    Olfaction may play an important role in regulating bird behavior, and has been suggested to be involved in feather-pecking. We investigated possible differences in the body odors of red junglefowl females by using an automated olfactometer which assessed the ability of trained mice to discriminate between the odors of uropygial gland secretions (the main carrier of potential individual odors in chickens) of six feather-pecked and six non-pecked birds. All mice were clearly able to discriminate between all individual red junglefowl odors, showing that each bird has an individual body odor. We analyzed whether it was more difficult to discriminate between the odors of two feather-pecked, or two non-pecked birds, than it was to discriminate between the odors of two randomly selected birds. This was not the case, suggesting that feather-pecked birds did not share a common odor signature. Analyses using gas chromatography and mass spectrometry showed that the composition of aliphatic carboxylic acids in uropygial gland secretions differed consistently between individuals. However, chemical composition did not vary according to feather-pecking status. We conclude that red junglefowl have individual body odors which appear to be largely based on differences in the relative abundance of aliphatic carboxylic acids, but there is no evidence of systematic differences between the body odors of pecked and non-pecked birds.

  9. Energetic Efficiency of red palm oil

    Directory of Open Access Journals (Sweden)

    Byron Jiménez

    2013-11-01

    Full Text Available The main goal of this paper is to determine the energy efficiency in the production of red palm oil (Elaeis guineensis by using the biophysical indicator EROI, postulated by the Ecological Economics. This indicator is applied to compare the energy used in the preparation of synthetic fertilizers (to fill its nutritional demands versus the energy contained in the oil. In 2009, there were 195.550 hectares of land planted with African palm in Ecuador (INEC, 2011. In addition, between 2002 and 2009, there were 2,7 million tons of red oil (FEDEPAL, 2010. It is determined that for each unit of energy consumed, 4.82 units of energy are contained in the red oil. The energy used in making pesticides for cultivation, consumed in transportation, refining, and post harvest is excluded because this other energy would drastically reduce the absolute data of the indicator, which is already inefficient for the high energy consumption it requires to generate the energy contained in the oil. On the other hand, agroecology has proven to be more efficient in the generation of energy per unit of invested energy (Altieri et. al., 2010; Moore, 2004.

  10. Red mud flocculation process in alumina production

    Science.gov (United States)

    Fedorova, E. R.; Firsov, A. Yu

    2018-05-01

    The process of thickening and washing red mud is a gooseneck of alumina production. The existing automated systems of the thickening process control involve stabilizing the parameters of the primary technological circuits of the thickener. The actual direction of scientific research is the creation and improvement of models and systems of the thickening process control by model. But the known models do not fully consider the presence of perturbing effects, in particular the particle size distribution in the feed process, distribution of floccules by size after the aggregation process in the feed barrel. The article is devoted to the basic concepts and terms used in writing the population balance algorithm. The population balance model is implemented in the MatLab environment. The result of the simulation is the particle size distribution after the flocculation process. This model allows one to foreseen the distribution range of floccules after the process of aggregation of red mud in the feed barrel. The mud of Jamaican bauxite was acting as an industrial sample of red mud; Cytec Industries of HX-3000 series with a concentration of 0.5% was acting as a flocculant. When simulating, model constants obtained in a tubular tank in the laboratories of CSIRO (Australia) were used.

  11. Moisture sorption of Thai red curry powder

    Directory of Open Access Journals (Sweden)

    Sudathip Inchuen

    2009-12-01

    Full Text Available Moisture sorption study was conducted on Thai red curry powder prepared by two different drying methods, viz. microwave and hot-air drying. Moisture sorption isotherms of the red curry powder at 30 C and water activity in the range of 0.113-0.970 were determined by a static gravimetric method. The isotherms exhibited Type III behaviour. The moisture sorption data were fitted to several sorption models and a non-linear regression analysis method was used to evaluate the constants of the sorption equations. The fit was evaluated using the coefficient of determination (R2, the reduced chi-square (2 and the root mean square error (RMSE. The GAB model followed by the Lewiski-3 model gave the best fit to the experimental data. The monolayer moisture content, taken as the safe minimum moisture level in the red curry powder, was determined using the BET equation and was found to range between 0.080 - 0.085 gram water per gram dry matter.

  12. Abrupt warming of the Red Sea

    Science.gov (United States)

    Raitsos, D. E.; Hoteit, I.; Prihartato, P. K.; Chronis, T.; Triantafyllou, G.; Abualnaja, Y.

    2011-07-01

    Coral reef ecosystems, often referred to as “marine rainforests,” concentrate the most diverse life in the oceans. Red Sea reef dwellers are adapted in a very warm environment, fact that makes them vulnerable to further and rapid warming. The detection and understanding of abrupt temperature changes is an important task, as ecosystems have more chances to adapt in a slowly rather than in a rapid changing environment. Using satellite derived sea surface and ground based air temperatures, it is shown that the Red Sea is going through an intense warming initiated in the mid-90s, with evidence for an abrupt increase after 1994 (0.7°C difference pre and post the shift). The air temperature is found to be a key parameter that influences the Red Sea marine temperature. The comparisons with Northern Hemisphere temperatures revealed that the observed warming is part of global climate change trends. The hitherto results also raise additional questions regarding other broader climatic impacts over the area.

  13. Nuclear power

    International Nuclear Information System (INIS)

    Abd Khalik Wood

    2005-01-01

    This chapter discussed the following topics related to the nuclear power: nuclear reactions, nuclear reactors and its components - reactor fuel, fuel assembly, moderator, control system, coolants. The topics titled nuclear fuel cycle following subtopics are covered: , mining and milling, tailings, enrichment, fuel fabrication, reactor operations, radioactive waste and fuel reprocessing. Special topic on types of nuclear reactor highlighted the reactors for research, training, production, material testing and quite detail on reactors for electricity generation. Other related topics are also discussed: sustainability of nuclear power, renewable nuclear fuel, human capital, environmental friendly, emission free, impacts on global warming and air pollution, conservation and preservation, and future prospect of nuclear power

  14. Nuclear power

    International Nuclear Information System (INIS)

    Bupp, I.C.

    1991-01-01

    Is a nuclear power renaissance likely to occur in the United States? This paper investigates the many driving forces that will determine the answer to that question. This analysis reveals some frequently overlooked truths about the current state of nuclear technology: An examination of the issues also produces some noteworthy insights concerning government regulations and related technologies. Public opinion will play a major role in the unfolding story of the nuclear power renaissance. Some observers are betting that psychological, sociological, and political considerations will hod sway over public attitudes. Others wager that economic and technical concerns will prevail. The implications for the nuclear power renaissance are striking

  15. Mechanical Behavior of Red Sandstone under Incremental Uniaxial Cyclical Compressive and Tensile Loading

    Directory of Open Access Journals (Sweden)

    Baoyun Zhao

    2017-01-01

    Full Text Available Uniaxial experiments were carried out on red sandstone specimens to investigate their short-term and creep mechanical behavior under incremental cyclic compressive and tensile loading. First, based on the results of short-term uniaxial incremental cyclic compressive and tensile loading experiments, deformation characteristics and energy dissipation were analyzed. The results show that the stress-strain curve of red sandstone has an obvious memory effect in the compressive and tensile loading stages. The strains at peak stresses and residual strains increase with the cycle number. Energy dissipation, defined as the area of the hysteresis loop in the stress-strain curves, increases nearly in a power function with the cycle number. Creep test of the red sandstone was also conducted. Results show that the creep curve under each compressive or tensile stress level can be divided into decay and steady stages, which cannot be described by the conventional Burgers model. Therefore, an improved Burgers creep model of rock material is constructed through viscoplastic mechanics, which agrees very well with the experimental results and can describe the creep behavior of red sandstone better than the Burgers creep model.

  16. The color red reduces snack food and soft drink intake.

    Science.gov (United States)

    Genschow, Oliver; Reutner, Leonie; Wänke, Michaela

    2012-04-01

    Based on evidence that the color red elicits avoidance motivation across contexts (Mehta & Zhu, 2009), two studies investigated the effect of the color red on snack food and soft drink consumption. In line with our hypothesis, participants drank less from a red labeled cup than from a blue labeled cup (Study 1), and ate less snack food from a red plate than from a blue or white plate (Study 2). The results suggest that red functions as a subtle stop signal that works outside of focused awareness and thereby reduces incidental food and drink intake. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Nuclear power

    International Nuclear Information System (INIS)

    1987-01-01

    ''Nuclear Power'' describes how a reactor works and examines the different designs including Magnox, AGR, RBMK and PWR. It charts the growth of nuclear generation in the world and its contributions to world energy resources. (author)

  18. Power stations

    International Nuclear Information System (INIS)

    Cawte, H.; Philpott, E.F.

    1980-01-01

    The object is to provide a method of operating a dual purpose power station so that the steam supply system is operated at a high load factor. The available steam not required for electricity generation is used to provide process heat and the new feature is that the process plant capacity is determined to make the most economic use of the steam supply system, and not to match the passout capacity of the turbine of the turbogenerator. The product of the process plant should, therefore, be capable of being stored. A dual-purpose power station with a nuclear-powered steam source, turbogenerating means connected to the steam source and steam-powered process plant susceptible to wide variation in its rate of operation is described. (U.K.)

  19. Nutritional profile of edible red marine seaweeds

    Directory of Open Access Journals (Sweden)

    Catarina Guedes Costa

    2014-06-01

    Full Text Available Marine biodiversity represents an exceptional source of natural resources. Their use in a sustainable way may ensure alternative food sources for human consumption, which scarcity is anticipated. Macroalgae, also known as seaweed, are an outstanding example of this biodiversity and are considered an excellent source of a wide number of chemical compounds with beneficial health effects [1]. According to their pigmentation, they can be distinguished in green (Chlorophytaea, brown (Phaeophytaea and red (Rhodophytaea, showing differences in nutritional and chemical compositions [1]. Some macroalgae are widely used as food ingredients in oriental countries as a good source of fiber and protein. Alternatively, they are also considered a source of nutraceuticals, providing health benefits such as anti-inflamatory, anti-allergic, antimutagenic, antitumor, antidiabetic, antioxidant, antihyperthensive and neuroprotective properties [2]. Indeed, macroalgae are a very attractive material for the food, pharmaceutical and cosmetic industries. According to some studies red seaweeds seem to be the most suitable source of proteins for human nutrition [3]. The aim of this study was to evaluate the nutritional profile of the most consumed species of red seaweed that are commercially available in the market. Red species as Palmaria palmata (Dulse, Porphyra tenera (Nori and Eisenia bicyclis (Arame, were analyzed. Moisture determination was performed using a Scaltec SMO01 moisture analyzer. The ashes were obtained by incineration at 500ºC. The protein content was determined using the Kjeldahl procedure and total fat was measured through Soxhlet method. The carbohydrates were calculated indirectly by difference. In addition, chlorides were volumetrically determined and vitamin E profile was analysed by HPLC/DAD/FLD. The algae samples are commercialized dry, so the moisture content was very low, around 10%. The ash content was around 10-17%. Protein levels ranged from

  20. red - an R package to facilitate species red list assessments according to the IUCN criteria

    Directory of Open Access Journals (Sweden)

    Pedro Cardoso

    2017-10-01

    Full Text Available The International Union for the Conservation of Nature Red List is the most useful database of species that are at risk of extinction worldwide, as it relies on a number of objective criteria and is now widely adopted. The R package red – IUCN Redlisting Tools - performs a number of spatial analyses based on either observed occurrences or estimated ranges. Functions include calculating Extent of Occurrence (EOO, Area of Occupancy (AOO, mapping species ranges, species distribution modelling using climate and land cover and calculating the Red List Index for groups of species. The package allows the calculation of confidence limits for all measures. Spatial data of species occurrences, environmental or land cover variables can be either given by the user or automatically extracted from several online databases. It outputs geographical range, elevation and country values, maps in several formats and vectorial data for visualization in Google Earth. Several examples are shown demonstrating the usefulness of the different methods. The red package constitutes an open platform for further development of new tools to facilitate red list assessments.

  1. red - an R package to facilitate species red list assessments according to the IUCN criteria.

    Science.gov (United States)

    Cardoso, Pedro

    2017-01-01

    The International Union for the Conservation of Nature Red List is the most useful database of species that are at risk of extinction worldwide, as it relies on a number of objective criteria and is now widely adopted. The R package red - IUCN Redlisting Tools - performs a number of spatial analyses based on either observed occurrences or estimated ranges. Functions include calculating Extent of Occurrence (EOO), Area of Occupancy (AOO), mapping species ranges, species distribution modelling using climate and land cover and calculating the Red List Index for groups of species. The package allows the calculation of confidence limits for all measures. Spatial data of species occurrences, environmental or land cover variables can be either given by the user or automatically extracted from several online databases. It outputs geographical range, elevation and country values, maps in several formats and vectorial data for visualization in Google Earth. Several examples are shown demonstrating the usefulness of the different methods. The red package constitutes an open platform for further development of new tools to facilitate red list assessments.

  2. redMaGiC: selecting luminous red galaxies from the DES Science Verification data

    Energy Technology Data Exchange (ETDEWEB)

    Rozo, E. [Univ. of Arizona, Tucson, AZ (United States). et al.

    2016-05-30

    We introduce redMaGiC, an automated algorithm for selecting Luminous Red Galaxies (LRGs). The algorithm was developed to minimize photometric redshift uncertainties in photometric large-scale structure studies. redMaGiC achieves this by self-training the color-cuts necessary to produce a luminosity-thresholded LRG sam- ple of constant comoving density. Additionally, we demonstrate that redMaGiC photo-zs are very nearly as accurate as the best machine-learning based methods, yet they require minimal spectroscopic training, do not suffer from extrapolation biases, and are very nearly Gaussian. We apply our algorithm to Dark Energy Survey (DES) Science Verification (SV) data to produce a redMaGiC catalog sampling the redshift range z ϵ [0.2,0.8]. Our fiducial sample has a comoving space density of 10-3 (h-1Mpc)-3, and a median photo-z bias (zspec zphoto) and scatter (σz=(1 + z)) of 0.005 and 0.017 respectively.The corresponding 5σ outlier fraction is 1.4%. We also test our algorithm with Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8) and Stripe 82 data, and discuss how spectroscopic training can be used to control photo-z biases at the 0.1% level.

  3. Stockpiling and Comprehensive Utilization of Red Mud Research Progress

    Science.gov (United States)

    Liu, Dong-Yan; Wu, Chuan-Sheng

    2012-01-01

    With increasing production of red mud, the environmental problems caused by it are increasingly serious, and thus the integrated treatment of red mud is imminent. This article provides an overview of the composition and the basic characteristics of red mud. The research progress of safe stockpiling and comprehensive utilization of red mud is summarized. The safe stockpiling of red mud can be divided into two aspects: the design and safe operation of the stocking yard. The comprehensive utilization of red mud can be further divided into three aspects: the effective recycling of components, resource utilization and application in the field of environmental protection. This paper points out that the main focus of previous studies on red mud stockpiling is cost reproduction and land tenure. The recovery of resources from red mud has a high value-added, but low level industrialization. The use of red mud as a building material and filler material is the most effective way to reduce the stockpiling of red mud. Red mud used for environmental remediation materials is a new hotspot and worth promoting for its simple processing and low cost.

  4. Introduction to electrical power and power electronics

    CERN Document Server

    Patel, Mukund R

    2012-01-01

    Power Generation, Distribution, and Utilization AC Power Fundamentals Common Aspects of Power Equipments AC Generator AC and DC Motors Transformer Power Cable Power Distribution Fault Current Analysis System ProtectionEconomic Use of PowerElectrochemical BatteryPower Electronics and Motor Drives Power Electronics Devices DC-DC Converters AC-DC-AC Converters Variable-Frequency Drives Quality of Power Power Converter CoolingAppendixIndex

  5. Perceived Organizational Red Tape and Organizational Performance in Public Services

    DEFF Research Database (Denmark)

    Jacobsen, Christian Bøtcher; Jakobsen, Mads Leth

    2018-01-01

    The claim that perceived organizational red tape hampers public services has become a central theme in public administration research. Surprisingly, however, few scholars have empirically examined the impact of perceived red tape on organizational performance. This study empirically analyzes how...... perceived organizational red tape among managers and frontline staff relates to objectively measured performance. The data consists of survey responses from teachers and principals at Danish upper secondary schools combined with grade-level administrative performance data. Based on theories of red tape...... and motivation crowding, we hypothesize that perceived organizational red tape reduces performance within such organizations. The empirical result is a small, negative relationship between staff perception of red tape and performance, and no relationship between manager-perceived red tape and performance....

  6. Biological oceanography of the red oceanic system

    Science.gov (United States)

    Theil, Hjalmar; Weikert, Horst

    1. In 1977, 1979 and 1980-81, investigations were carried out which aimed at evaluating the potential risks from mining metalliferous muds precipating in the Atlantis II Deep of the central Red Sea. This environmental research was initiated by the Saudi Sudanese Red Sea Joint Commission in order to avoid any danger for the Red Sea ecosystem. The broad environmental research programme coherent studies in physical, chemical, biological, and geological oceanography as well as toxicological investigations in the oceanic and in reef zones. We summarise the results from our biological fiels studies in the open sea. 2. The biological investigations were concentrated on the area of the Atlantis II Deep. Benthos was sampled between 700-2000m. For comparison a few samples were also taken further north in the central Red Sea, and to east and west along the flanking deep terraces (500-1000m). Plankton studies covered the total water column above the Deep, and were extended along the axial through to north and south. 3. Benthos sampling was carried out using a heavy closing trawl, a large box grab (box size 50 × 50 cm), Van Veen grabs and traps; photographic surveys were made a phototrap and a photosled. Community respiration was measured with a ship-board method using grab subsamples. Nutrient concentrations, seston and phytoplankton standing stocks as well as in situ primary production were determined from hydrocast samples. Data on zooplankton and micronekton composition and standing stock were obtained from samples collected using different multiple opening-and-closing nets equipped with 100 μm, 300 μm, and 1000 μm mesh sizes. Daily and ontogenetical vertical migration patterns were studied by comparisons of data from midday and midnight tows. 4. Throughout the whole area the sediment is a pteropod ooze containing low contentrations of organic matter; measured organic carbon and nitrogen contents were 0.5 and 0.05% respectively, and chloroplastic pigment equivalents

  7. Solar-like oscillations in red giants observed with Kepler: comparison of global oscillation parameters from different methods

    DEFF Research Database (Denmark)

    Hekker, Saskia; Elsworth, Yvonne; De Ridder, Joris

    2011-01-01

    investigate the differences in results for global oscillation parameters of G and K red-giant stars due to different methods and definitions. We also investigate uncertainties originating from the stochastic nature of the oscillations. Methods: For this investigation we use Kepler data obtained during...... obtain results for the frequency of maximum oscillation power (ν_max) and the mean large separation () from different methods for over one thousand red-giant stars. The results for these parameters agree within a few percent and seem therefore robust to the different analysis methods and definitions...

  8. Photonic surfaces for designable nonlinear power shaping

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Roshni, E-mail: rbiswas@usc.edu; Povinelli, Michelle L. [Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States)

    2015-02-09

    We propose a method for designing nonlinear input-output power response based on absorptive resonances of nanostructured surfaces. We show that various power transmission trends can be obtained by placing a photonic resonance mode at the appropriate detuning from the laser wavelength. We demonstrate our results in a silicon photonic crystal slab at a laser wavelength of 808 nm. We quantify the overall spectral red shift as a function of laser power. The shift results from absorptive heating and the thermo-optic effect. We then demonstrate devices with increasing, decreasing, and non-monotonic transmission as a function of laser power. The transmission changes are up to 7.5 times larger than in unpatterned silicon. The strong nonlinear transmission is due to a combination of resonantly enhanced absorption, reduced thermal conductivity, and the resonant transmission lineshape. Our results illustrate the possibility of designing different nonlinear power trends within a single materials platform at a given wavelength of interest.

  9. Photonic surfaces for designable nonlinear power shaping

    International Nuclear Information System (INIS)

    Biswas, Roshni; Povinelli, Michelle L.

    2015-01-01

    We propose a method for designing nonlinear input-output power response based on absorptive resonances of nanostructured surfaces. We show that various power transmission trends can be obtained by placing a photonic resonance mode at the appropriate detuning from the laser wavelength. We demonstrate our results in a silicon photonic crystal slab at a laser wavelength of 808 nm. We quantify the overall spectral red shift as a function of laser power. The shift results from absorptive heating and the thermo-optic effect. We then demonstrate devices with increasing, decreasing, and non-monotonic transmission as a function of laser power. The transmission changes are up to 7.5 times larger than in unpatterned silicon. The strong nonlinear transmission is due to a combination of resonantly enhanced absorption, reduced thermal conductivity, and the resonant transmission lineshape. Our results illustrate the possibility of designing different nonlinear power trends within a single materials platform at a given wavelength of interest

  10. Wind power

    International Nuclear Information System (INIS)

    Gipe, P.

    2007-01-01

    This book is a translation of the edition published in the USA under the title of ''wind power: renewable energy for home, farm and business''. In the wake of mass blackouts and energy crises, wind power remains a largely untapped resource of renewable energy. It is a booming worldwide industry whose technology, under the collective wing of aficionados like author Paul Gipe, is coming of age. Wind Power guides us through the emergent, sometimes daunting discourse on wind technology, giving frank explanations of how to use wind technology wisely and sound advice on how to avoid common mistakes. Since the mid-1970's, Paul Gipe has played a part in nearly every aspect of wind energy development from installing small turbines to promoting wind energy worldwide. As an American proponent of renewable energy, Gipe has earned the acclaim and respect of European energy specialists for years, but his arguments have often fallen on deaf ears at home. Today, the topic of wind power is cropping up everywhere from the beaches of Cape Cod to the Oregon-Washington border, and one wind turbine is capable of producing enough electricity per year to run 200 average American households. Now, Paul Gipe is back to shed light on this increasingly important energy source with a revised edition of Wind Power. Over the course of his career, Paul Gipe has been a proponent, participant, observer, and critic of the wind industry. His experience with wind has given rise to two previous books on the subject, Wind Energy Basics and Wind Power for Home and Business, which have sold over 50,000 copies. Wind Power for Home and Business has become a staple for both homeowners and professionals interested in the subject, and now, with energy prices soaring, interest in wind power is hitting an all-time high. With chapters on output and economics, Wind Power discloses how much you can expect from each method of wind technology, both in terms of energy and financial savings. The book updated models

  11. Mechanisms of immune red cell destruction, and red cell compatibility testing

    International Nuclear Information System (INIS)

    Garratty, G.

    1983-01-01

    The immune destruction of red cells can occur as a complement-mediated intravascular process, or extravascularly, where the red cells are destroyed by macrophages following interaction with cell-bound IgG1, IgG3, and/or C3b. Many of the factors that affect this in vivo destruction are not taken into account during in vitro pretransfusion compatibility testing. At present, even by use of more elaborate tests, it is difficult to accurately predict the fate of a transfused unit of blood. By using some simple information, such as antibody specificity and thermal range, it is sometimes possible to predict the outcome of transfusing a unit of blood that is incompatible in vitro. At other times it may be necessary to utilize 51 Cr-labeled red cells to determine the risk of transfusing such units. Because of the paucity of reported clinical correlations, macrophage/monocyte monolayer assays are of little practical value at present

  12. Can Lutjanus purpureus (South red snapper be "legally" considered a red snapper (Lutjanus campechanus?

    Directory of Open Access Journals (Sweden)

    Grazielle Gomes

    2008-01-01

    Full Text Available Red snappers (Lutjanus purpureus in Brazil and Lutjanus campechanus in USA and Gulf of Mexico are both under clear effect of overfishing. Because of their high morphological similarity it has already been suggested that they could possibly be considered as a single species. To investigate the degree of similarity and the genetic structure of red snapper populations we constructed a common dataset of partial D-loop mtDNA sequences of L. purpureus from Brazil (Amapá, Pará and Maranhão and L. campechanus from the Atlantic coast of the USA (Florida, Louisiana and Mississippi. Phylogenetic and population genetic analyses surprisingly depicted high similarity between L. campechanus and L. purpureus, compatible with the hypothesis of a single species of red snapper for the Western Atlantic Ocean. These preliminary but very curious findings open an important discussion regarding the legislation involved on the capture of this overexploited fish resources as well as regarding their taxonomy.

  13. NMR water-proton spin-lattice relaxation time of human red blood cells and red blood cell suspensions

    International Nuclear Information System (INIS)

    Sullivan, S.G.; Rosenthal, J.S.; Winston, A.; Stern, A.

    1988-01-01

    NMR water-proton spin-lattice relaxation times were studied as probes of water structure in human red blood cells and red blood cell suspensions. Normal saline had a relaxation time of about 3000 ms while packed red blood cells had a relaxation time of about 500 ms. The relaxation time of a red blood cell suspension at 50% hematocrit was about 750 ms showing that surface charges and polar groups of the red cell membrane effectively structure extracellular water. Incubation of red cells in hypotonic saline increases relaxation time whereas hypertonic saline decreases relaxation time. Relaxation times varied independently of mean corpuscular volume and mean corpuscular hemoglobin concentration in a sample population. Studies with lysates and resealed membrane ghosts show that hemoglobin is very effective in lowering water-proton relaxation time whereas resealed membrane ghosts in the absence of hemoglobin are less effective than intact red cells. 9 refs.; 3 figs.; 1 table

  14. Malaysia power

    Energy Technology Data Exchange (ETDEWEB)

    Husin, Z.A. (Tenaga Nasional Berhad (Malaysia))

    1994-09-01

    Describes the organisation of the Malaysian electric power industry and the role of natural gas and coal in power generation in the country. At present, electricity is produced by three utilities: Tenaga Nasional Berhad (TNB) which was fully privatised in May 1992 with the Government holding about 73% of the equity, Sarawak Electricity Supply Corporation (SESCO) which the Government plans to privatise soon, and Sabah Electricity Board (SEB). These have installed capacities of 7000 MW, 400 MW and 350 MW, respectively. Five independent power producers have been given licences to build, own and operate power plants with a total installed capacity of 4000 MW. Natural gas is expected to account for about 72% of Malaysia's power generating fuel by the year 2010, compared to about 50% at present. Malaysia currently has only one coal-fired plant, but its expansion is in the final stage of contract awards. A number of small capacity coal-fired plants are being planned for Sabah and Sarawak where the bulk of Malaysia's coal resources are located. 3 figs., 1 photo.

  15. MONTE-CARLO Simulations ``QUANTUM''-``NOISE'' POWER-SPECTRUM 0 =(F =ma) =0 Uniform-Velocity Pareto/Red/Beethoven-Law VS 0 ≠(F =ma) ≠0 Uniform-Acceleration/Deceleration/Bremsstrahlung Archimedes-(Euclid-Descartes)-Zipf/Pink/Flicker/Bach-Law UNIVERSALITY INEVITABILITY!!!

    Science.gov (United States)

    Louis, T. T. L.; Siegel, Edward Carl-Ludwig; Young, Frederic; Smith, Adolph

    2013-03-01

    Dynamics vs usual by-rote kinematics treatment/lack of understanding, via Siegel[AIP Shock-Physics Confs. Chicago(2011); Seattle(2013)] simple classical-mechanics/dynamics simple-insights]-Panofsky-Phillips[E&M (1960s)],of Monte Carlo[Kaplan et.al.[PRL 107, 201601 (11)]:'''Noise', Sign-Problems & Statistics'']-simulations' {Hamersley-Handscombe, Monte Carlo Methods, Methuen(64-75)}``noises'' power-spectra{SEMINAL Montroll [(60s-80s)}-Boccara[ ``Modeling'' ``Complex''-Sys.(02)-ch.-8/p.-311]-West et.al.[Physics of Fractal-Operators, Springer(00)]-Shlesinger-Lindenberg-Handel-van Vliet-Jonscher-Ngai-...-Siegel[Schrodinger Symp., Imperial-College (1987);Copenhagen-Onterp. 50-Yrs. After Como-Lect.,Symp.Fdns.Mod.Phys., Joensu(87)]}, in the light of Siegel[MRS Fall-Mtgs. Boston: Symp. Fractals(89)-5-papers!!!; Symp. Scaling(90); Symp.Transport in Geometric-Constraints(90)] power-law decay algebraicity vs. white/flat/functionless [analogous to Fokker-Planck-eqn. two-terms Dichotomy, relatively: static/non-diffusive vs diffusive!!!] but dimensionality-dependence: first-odd-integer Z vs. first-even-integer Z: 2-D bulk-region -area - dominated constant

  16. Red wines good, white wines bad?

    International Nuclear Information System (INIS)

    Van Velden, D.P.; Mansvelt, E.P.G.; Troup, G.J.

    2002-01-01

    Full text: In 1994, free radicals were discovered in red wines, but only in whites exposed to skins and seeds, and/or oak. The radicals are on the phenolics, and therefore a measure of phenolic content. In 1995, Fuhrman, Levy and Aviram published a study showing antioxidant effects of red wine in the standard Israeli diet, but pro-oxidant effects of the white wine used. No phenolic analysis was done, but low or no phenolics were suspected. Letters to the winery used by Aviram proved fruitless. In 2001, Aviram admits that to see a significant antioxidant effect from white wine, he must make his own, giving it skin and seed contact, and adding alcohol to the fermenting stage, to leach out more tannin from the seeds. This would be unsaleable as a table wine, but not as a 'fortified' or 'dessert' wine. A completely independent study by van Velden in South Africa, with phenol analysis of wines, shows pro- oxidant behaviour of white wines low or lacking in phenolic content. This will be summarised. A Japanese study of the antioxidant properties of some wines shows none for wines low or lacking in catechin content. In the 1950's, two similar but independent studies on different laboratory animals showed no ill effects from 10% alcohol red wine in their diet, but serious effects from 10% pure alcohol - water mix. Conclusion. Drinking only of white wines lacking in phenols, either due to 'fining', or to deliberate avoidance in making, at the recommended 'moderate' drinking level, may be deleterious to cardiovascular health, because of their pro-oxidant action, now established

  17. Hidden values in bauxite residue (red mud): recovery of metals.

    Science.gov (United States)

    Liu, Yanju; Naidu, Ravi

    2014-12-01

    Bauxite residue (red mud) is a hazardous waste generated from alumina refining industries. Unless managed properly, red mud poses significant risks to the local environment due to its extreme alkalinity and its potential impacts on surface and ground water quality. The ever-increasing generation of red mud poses significant challenges to the aluminium industries from management perspectives given the low proportion that are currently being utilized beneficially. Red mud, in most cases, contains elevated concentrations of iron in addition to aluminium, titanium, sodium and valuable rare earth elements. Given the scarcity of iron supply globally, the iron content of red mud has attracted increasing research interest. This paper presents a critical overview of the current techniques employed for iron recovery from red mud. Information on the recovery of other valuable metals is also reviewed to provide an insight into the full potential usage of red mud as an economic resource rather than a waste. Traditional hydrometallurgy and pyrometallurgy are being investigated continuously. However, in this review several new techniques are introduced that consider the process of iron recovery from red mud. An integrated process which can achieve multiple additional values from red mud is much preferred over the single process methods. The information provided here should help to improve the future management and utilization of red mud. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Administration of red ginseng ameliorates memory decline in aged mice.

    Science.gov (United States)

    Lee, Yeonju; Oh, Seikwan

    2015-07-01

    It has been known that ginseng can be applied as a potential nutraceutical for memory impairment; however, experiments with animals of old age are few. To determine the memory enhancing effect of red ginseng, C57BL/6 mice (21 mo old) were given experimental diet pellets containing 0.12% red ginseng extract (approximately 200 mg/kg/d) for 3 mo. Young and old mice (4 mo and 21 mo old, respectively) were used as the control group. The effect of red ginseng, which ameliorated memory impairment in aged mice, was quantified using Y-maze test, novel objective test, and Morris water maze. Red ginseng ameliorated age-related declines in learning and memory in older mice. In addition, red ginseng's effect on the induction of inducible nitric oxide synthase and proinflammatory cytokines was investigated in the hippocampus of aged mice. Red ginseng treatment suppressed the production of age-processed inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor-α, and interleukin-1β expressions. Moreover, it was observed that red ginseng had an antioxidative effect on aged mice. The suppressed glutathione level in aged mice was restored with red ginseng treatment. The antioxidative-related enzymes Nrf2 and HO-1 were increased with red ginseng treatment. The results revealed that when red ginseng is administered over long periods, age-related decline of learning and memory is ameliorated through anti-inflammatory activity.

  19. Effects of Red Blood Cell Aggregation on the Apparent Viscosity of Blood Flow in Tubes.

    Science.gov (United States)

    Hitt, Darren L.; Lowe, Mary L.

    1996-11-01

    In arterioles and venules (20-200μ diameter), the low shear rates enable red blood cells to form aggregate structures of varying sizes and morphology. The size and distribution of the aggregates affect the flow impedance within a microvascular network; this effect may be characterized by an "apparent viscosity". In this study, we measure the apparent viscosity of blood flow in 50μ glass tubes as a function of shear rate and red blood cell volume fraction (hematocrit); for a fixed tube geometry and an imposed flow rate, the viscosity is determined by measuring the pressure drop across the tube. To correlate the apparent viscosity with the size and spatial distribution of the aggregates in the flow, video images of the flow are recorded and analyzed using power spectral techniques. Pig blood and sheep blood are used as the models for aggregating and non-aggregating blood, respectively. Supported by NSF PFF Award CTS-9253633

  20. Highly efficient red OLEDs using DCJTB as the dopant and delayed fluorescent exciplex as the host.

    Science.gov (United States)

    Zhao, Bo; Zhang, Tianyou; Chu, Bei; Li, Wenlian; Su, Zisheng; Wu, Hairuo; Yan, Xingwu; Jin, Fangming; Gao, Yuan; Liu, Chengyuan

    2015-05-29

    In this manuscript, we demonstrated a highly efficient DCJTB emission with delayed fluorescent exciplex TCTA:3P-T2T as the host. For the 1.0% DCJTB doped concentration, a maximum luminance, current efficiency, power efficiency and EQE of 22,767 cd m(-2), 22.7 cd A(-1), 21.5 lm W(-1) and 10.15% were achieved, respectively. The device performance is the best compared to either red OLEDs with traditional fluorescent emitter or traditional red phosphor of Ir(piq)3 doped into CBP host. The extraction of so high efficiency can be explained as the efficient triplet excitons up-conversion of TCTA:3P-T2T and the energy transfer from exciplex host singlet state to DCJTB singlet state.