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Sample records for blue hook stars

  1. Spectroscopic analyses of the blue hook stars in NGC 2808:A more stringent test of the late hot flasher scenario

    OpenAIRE

    Moehler, S.; Sweigart, A. V.; Landsman, W. B.; Hammer, N. J.; Dreizler, S.

    2004-01-01

    Recent UV observations of the globular cluster NGC 2808 (Brown et al. 2001) show a significant population of hot stars fainter than the zero-age horizontal branch ("blue hook" stars), which cannot be explained by canonical stellar evolution. Their results suggest that stars which experience unusually large mass loss on the red giant branch and which subsequently undergo the helium core flash while descending the white dwarf cooling curve could populate this region. Theory predicts that these ...

  2. A possible formation channel for blue hook stars in globular cluster

    CERN Document Server

    Lei, Zhenxin; Zhang, Fenghui; Han, Zhanwen

    2015-01-01

    The formation mechanism for blue hook (BHk) stars in globular clusters (GCs) is still unclear. Following one of the possible scenario, named late hot flash scenario, we proposed that tidally enhanced stellar wind in binary evolution may provide the huge mass loss on the red giant branch (RGB) and produce BHk stars. Employing the detailed stellar evolution code, Modules for Experiments in Stellar Astrophysics (MESA), we investigated the contributions of tidally enhanced stellar wind as a possible formation channel for BHk stars in GCs. We evolved the primary stars with different initial orbital periods using the binary module in MESA (version 6208) from zero age main-sequence (ZAMS) to post horizontal branch (HB) stage, and obtained their evolution parameters which are compared with the observation. The results are consistent with observation in the color-magnitude diagram (CMD) and the logg-Teff plane for NGC 2808, which is an example GC hosting BHk stars. However, the helium abundance in the surface for our ...

  3. A possible formation channel for blue hook stars in globular clusters

    Science.gov (United States)

    Lei, Zhenxin; Chen, Xuemei; Zhang, Fenghui; Han, Zhanwen

    2015-05-01

    The formation mechanism for blue hook (BHk) stars in globular clusters (GCs) is still unclear. Following one of the possible scenarios, called the late hot flash scenario, we propose that a tidally enhanced stellar wind in binary evolution might provide the huge mass loss on the red giant branch (RGB) and produce BHk stars. Employing the detailed stellar evolution code MESA (Modules for Experiments in Stellar Astrophysics), we have investigated the contributions of tidally enhanced stellar wind as a possible formation channel for BHk stars in GCs. We evolved the primary stars with different initial orbital periods using the binary module in MESA (version 6208) from the zero-age main-sequence (ZAMS) to the post-horizontal branch (HB) stage, and obtained their evolution parameters, which are compared with the observation. The results are consistent with observations in the colour-magnitude diagram and the log g-Teff plane for NGC 2808, which is an example GC hosting BHk stars. However, the helium abundance in the surface for our models is higher than the one obtained in BHk stars. This discrepancy between our models and observations is possibly due to the fact that gravitational settling and radiative levitation, which are common processes in hot HB stars, are not considered in the models as well as the fact that the flash mixing efficiency might be overestimated in the calculations. Our results suggest that tidally enhanced stellar wind in binary evolution is able to naturally provide the huge mass loss on the RGB needed for the late hot flash scenario, and it is a possible and reasonable formation channel for BHk stars in GCs.

  4. A possible formation channel for blue hook stars in globular cluster - II. Effects of metallicity, mass ratio, tidal enhancement efficiency and helium abundance

    CERN Document Server

    Lei, Zhenxin; Zeng, Aihua; Shen, Lihua; Lan, Zhongjian; Jiang, Dengkai; Han, Zhanwen

    2016-01-01

    Employing tidally enhanced stellar wind, we studied in binaries the effects of metallicity, mass ratio of primary to secondary, tidal enhancement efficiency and helium abundance on the formation of blue hook (BHk) stars in globular clusters (GCs). A total of 28 sets of binary models combined with different input parameters are studied. For each set of binary model, we presented a range of initial orbital periods that is needed to produce BHk stars in binaries. All the binary models could produce BHk stars within different range of initial orbital periods. We also compared our results with the observation in the Teff-logg diagram of GC NGC 2808 and {\\omega} Cen. Most of the BHk stars in these two GCs locate well in the region predicted by our theoretical models, especially when C/N-enhanced model atmospheres are considered. We found that mass ratio of primary to secondary and tidal enhancement efficiency have little effects on the formation of BHk stars in binaries, while metallicity and helium abundance would...

  5. Ecology of blue straggler stars

    CERN Document Server

    Carraro, Giovanni; Beccari, Giacomo

    2015-01-01

    The existence of blue straggler stars, which appear younger, hotter, and more massive than their siblings, is at odds with a simple picture of stellar evolution. Such stars should have exhausted their nuclear fuel and evolved long ago to become cooling white dwarfs. They are found to exist in globular clusters, open clusters, dwarf spheroidal galaxies of the Local Group, OB associations and as field stars. This book summarises the many advances in observational and theoretical work dedicated to blue straggler stars. Carefully edited extended contributions by well-known experts in the field cover all the relevant aspects of blue straggler stars research: Observations of blue straggler stars in their various environments; Binary stars and formation channels; Dynamics of globular clusters; Interpretation of observational data and comparison with models. The book also offers an introductory chapter on stellar evolution written by the editors of the book.

  6. Variable blue straggler stars in NGC 5466

    International Nuclear Information System (INIS)

    Nine variable blue stragglers have been found in the globular cluster NGC 5466. The six dwarf Cepheids in this cluster coexist in the instability strip with other nonvariable stars. The three eclipsing binaries are among the hottest of the blue stragglers. The hypothesis is discussed that all blue stragglers in this cluster have undergone mass transfer in close binaries. Under this hypothesis, rotation and spin-down play important roles in controlling the evolution of blue stragglers in old clusters and in affecting some of their observational properties. 14 refs

  7. Blue Horizontal Branch Stars in M92

    CERN Document Server

    Cohen, J G

    1997-01-01

    We have analyzed high dispersion and high precision spectra of 5 blue horizontal branch stars in the globular cluster M92 to establish that the projected rotational velocity for these stars ranges from 15 to 40 \\kms. This is larger than that expected based on the rotation of their main sequence progenitors, the spin down of rotation with age, and the conservation of angular momentum. Possible explanations include a rapidly rotating stellar core. An abundance analysis of these spectra of these blue HB stars in M92 yields the same results as have been obtained from the giants in this cluster. There is a hint of a trend of higher abundance as the projected surface rotational velocity increases, which could be chance and requires confirmation.

  8. CENSUS OF BLUE STARS IN SDSS DR8

    Energy Technology Data Exchange (ETDEWEB)

    Scibelli, Samantha [Burnt Hills-Ballston Lake High School, 88 Lake Hill Road, Ballston, NY 12027 (United States); Newberg, Heidi Jo; Carlin, Jeffrey L. [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180 (United States); Yanny, Brian, E-mail: heidi@rpi.edu [Experimental Astrophysics Group, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)

    2015-01-01

    We present a census of the 12,060 spectra of blue objects ((g – r){sub 0} < –0.25) in the Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8). As part of the data release, all of the spectra were cross-correlated with 48 template spectra of stars, galaxies, and QSOs to determine the best match. We compared the blue spectra by eye to the templates assigned in SDSS DR8. 10,856 of the objects matched their assigned template, 170 could not be classified due to low signal-to-noise ratio, and 1034 were given new classifications. We identify 7458 DA white dwarfs, 1145 DB white dwarfs, 273 rarer white dwarfs (including carbon, DZ, DQ, and magnetic), 294 subdwarf O stars, 648 subdwarf B stars, 679 blue horizontal branch stars, 1026 blue stragglers, 13 cataclysmic variables, 129 white dwarf-M dwarf binaries, 36 objects with spectra similar to DO white dwarfs, 179, quasi-stellar objects (QSOs), and 10 galaxies. We provide two tables of these objects, sample spectra that match the templates, figures showing all of the spectra that were grouped by eye, and diagnostic plots that show the positions, colors, apparent magnitudes, proper motions, etc., for each classification. Future surveys will be able to use templates similar to stars in each of the classes we identify to automatically classify blue stars, including rare types.

  9. Census of blue stars in SDSS DR8

    CERN Document Server

    Scibelli, Samantha; Carlin, Jeffrey L; Yanny, Brian

    2014-01-01

    We present a census of the 12,060 spectra of blue objects ($(g-r)_0<-0.25$) in the Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8). As part of the data release, all of the spectra were cross-correlated with 48 template spectra of stars, galaxies and QSOs to determine the best match. We compared the blue spectra by eye to the templates assigned in SDSS DR8. 10,856 of the objects matched their assigned template, 170 could not be classified due to low signal-to-noise (S/N), and 1034 were given new classifications. We identify 7458 DA white dwarfs, 1145 DB white dwarfs, 273 rarer white dwarfs (including carbon, DZ, DQ, and magnetic), 294 subdwarf O stars, 648 subdwarf B stars, 679 blue horizontal branch stars, 1026 blue stragglers, 13 cataclysmic variables, 129 white dwarf - M dwarf binaries, 36 objects with spectra similar to DO white dwarfs, 179 QSOs, and 10 galaxies. We provide two tables of these objects, sample spectra that match the templates, figures showing all of the spectra that were grouped by ...

  10. Characterizing Pale Blue Dots Around FGKM Stars

    Science.gov (United States)

    Rugheimer, Sarah; Kaltenegger, Lisa; Sasselov, Dimitar; Segura, Antigona

    2015-12-01

    Exoplanet characterization of small rocky worlds will be a main focus in the coming decades. For future telescopes like JWST and UVOIR/HDST, an exoplanet’s host star will influence our ability to detect and interpret spectral features, including biosignatures. We present a complete suit of stellar models and a grid of model atmospheres for Earth-like planets at equivalent stages of geological evolution in their HZ for stellar effective temperature from Teff = 2300K to 7000K, sampling the entire FGKM stellar type range. Since M dwarfs are simultaneously the most numerous in the universe, the most active, and the most likely stars to host terrestrial exoplanets, we focus in particular on the range of UV emission possible in each sub M spectral class. The UV emission from a planet's host star dominates the photochemistry and thus the resultant observable spectral features of the planet. Using the latest UV spectra obtained by HST and IUE we model the effect of stellar activity on Earth-like planets. We also model the amount of UV flux reaching the surface for Earth-like planets at various geological epochs ranging from a pre-biotic world through the rise of oxygen and for Earth-like planets orbiting FGKM stars at equivalent stages of evolution. When modeling the remotely detectable spectra of these planets we focus on the primary detectable atmospheric features that indicate habitability on Earth, namely: H2O, CO2, O3, CH4, N2O and CH3Cl. We model spectra of Earth-like planets orbiting our grid of FGKM stars in the VIS/NIR (0.4 - 4 μm) and the IR (5 - 20 μm) range as input for future missions and concepts like UVOIR/HDST and JWST.

  11. First Evidence of Circumstellar Disks around Blue Straggler Stars

    CERN Document Server

    De Marco, O; Ouellette, J A; Zurek, D R; Shara, M M; Marco, Orsola De; Lanz, Thierry; Ouellette, John A.; Zurek, David; Shara, Michael M.

    2004-01-01

    We present an analysis of optical HST/STIS and HST/FOS spectroscopy of 6 blue stragglers found in the globular clusters M3, NGC6752 and NGC6397. These stars are a subsample of a set of ~50 blue stragglers and stars above the main sequence turn-off in four globular clusters which will be presented in an forthcoming paper. All but the 6 stars presented here can be well fitted with non-LTE model atmospheres. The 6 misfits, on the other hand, possess Balmer jumps which are too large for the effective temperatures implied by their Paschen continua. We find that our data for these stars are consistent with models only if we account for extra absorption of stellar Balmer photons by an ionized circumstellar disk. Column densities of HI and CaII are derived as are the the disks' thicknesses. This is the first time that a circumstellar disk is detected around blue stragglers. The presence of magnetically-locked disks attached to the stars has been suggested as a mechanism to lose the large angular momentum imparted by ...

  12. Super Star Clusters in the Blue Dwarf Galaxy UM 462

    OpenAIRE

    Vanzi, Leonardo

    2003-01-01

    I present optical observations of the Blue Compact Dwarf Galaxy UM 462. The images of this galaxy show several bright compact sources. A careful study of these sources has revealed their nature of young Super Star Clusters. The ages determined from the analysis of the stellar continuum and $H\\alpha$ are between few and few tens Myr. The total star formation taking place into the clusters is about 0.05 $\\mathrm{M_{\\odot}/yr}$. The clusters seem to be located at the edges of two large round-lik...

  13. Chemical abundances of blue straggler stars in Galactic Globular Clusters

    CERN Document Server

    Lovisi, L

    2014-01-01

    By using the high resolution spectrograph FLAMES@VLT we performed the first systematic campaign devoted to measure chemical abundances of blue straggler stars (BSSs). These stars, whose existence is not predicted by the canonical stellar evolutionary theory, are likely the product of the interactions between stars in the dense environment of Globular Clusters. Two main scenarios for BSS formation (mass transfer in binary systems and stellar collisions) have been proposed and hydrodynamical simulations predict different chemical patterns in the two cases, in particular C and O depletion for mass transfer BSSs. In this contribution, the main results for BSS samples in 6 Globular Clusters and their interpretation in terms of BSS formation processes are discussed. For the first time, evidence of radiative levitation in the shallow envelopes of BSSs hotter than $\\sim$8000 K has been found. C and O depletion for some BSSs has been detected in 47 Tucanae, M30 and $\\omega$ Centauri thus suggesting a mass transfer ori...

  14. Blue supergiants as descendants of magnetic main sequence stars

    Science.gov (United States)

    Petermann, I.; Langer, N.; Castro, N.; Fossati, L.

    2015-12-01

    About 10% of the massive main sequence stars have recently been found to host a strong, large scale magnetic field. Both, the origin and the evolutionary consequences of these fields are largely unknown. We argue that these fields may be sufficiently strong in the deep interior of the stars to suppress convection near the outer edge of their convective core. We performed parametrised stellar evolution calculations and assumed a reduced size of the convective core for stars in the mass range 16M⊙ to 28M⊙ from the zero age main sequence until core carbon depletion. We find that such models avoid the coolest part of the main sequence band, which is usually filled by evolutionary models that include convective core overshooting. Furthermore, our "magnetic" models populate the blue supergiant region during core helium burning, i.e., the post-main sequence gap left by ordinary single star models, and some of them end their life in a position near that of the progenitor of Supernova 1987A in the Hertzsprung-Russell diagram. Further effects include a strongly reduced luminosity during the red supergiant stage, and downward shift of the limiting initial mass for white dwarf and neutron star formation.

  15. On the Blue Loops of Intermediate-Mass Stars

    CERN Document Server

    Walmswell, J J; Eldridge, J J

    2015-01-01

    We consider the blue loops in the Hertzsprung-Russell diagram that occur when intermediate-mass stars begin core helium burning. It has long been known that the excess of helium above the burning shell, the result of the contraction of the convective core during core hydrogen burning, has the effect of making such stars redder and larger than they would be otherwise. The outward motion of the burning shell in mass removes this excess and triggers the loop. Hitherto nobody has attempted to demonstrate why the excess helium has this effect. We consider the effect of the local opacity, which is reduced by excess helium, the shell fuel supply, which is also reduced, and the local mean molecular weight, which is increased. We demonstrate that the mean molecular weight is the decisive reddening factor. The opacity has a much smaller effect and a reduced fuel supply actually favours blueward motion.

  16. Blue supergiants as descendants of magnetic main sequence stars

    CERN Document Server

    Petermann, I; Castro, N; Fossati, L

    2015-01-01

    About 10$\\%$ of the massive main sequence stars have recently been found to host a strong, large scale magnetic field. Both, the origin and the evolutionary consequences of these fields are largely unknown. We argue that these fields may be sufficiently strong in the deep interior of the stars to suppress convection near the outer edge of their convective core. We performed parametrised stellar evolution calculations and assumed a reduced size of the convective core for stars in the mass range 16 M$_{\\odot}$ to 28 M$_{\\odot}$ from the zero age main sequence until core carbon depletion. We find that such models avoid the coolest part of the main sequence band, which is usually filled by evolutionary models that include convective core overshooting. Furthermore, our `magnetic' models populate the blue supergiant region during core helium burning, i.e., the post-main sequence gap left by ordinary single star models, and some of them end their life in a position near that of the progenitor of Supernova 1987A in t...

  17. Spinning like a blue straggler: the population of fast rotating blue straggler stars in ω Centauri

    Energy Technology Data Exchange (ETDEWEB)

    Mucciarelli, A.; Lovisi, L.; Ferraro, F. R.; Dalessandro, E.; Lanzoni, B. [Dipartimento di Fisica and Astronomia, Università degli Studi di Bologna, Viale Berti Pichat 6/2, I-40127 Bologna (Italy); Monaco, L. [European Southern Observatory, Casilla 19001, Santiago (Chile)

    2014-12-10

    By using high-resolution spectra acquired with FLAMES-GIRAFFE at the ESO/VLT, we measured the radial and rotational velocities for 110 blue straggler stars (BSSs) in ω Centauri, the globular cluster-like stellar system harboring the largest known BSS population. According to their radial velocities, 109 BSSs are members of the system. The rotational velocity distribution is very broad, with the bulk of BSSs spinning at less than ∼40 km s{sup –1} (in agreement with the majority of such stars observed in other globular clusters) and a long tail reaching ∼200 km s{sup –1}. About 40% of the sample has v{sub e} sin i > 40 km s{sup –1} and about 20% has v{sub e} sin i > 70 km s{sup –1}. Such a large fraction is very similar to the percentage of fast rotating BSSs observed in M4. Thus, ω Centauri is the second stellar cluster, beyond M4, with a surprisingly high population of fast spinning BSSs. We found a hint of radial behavior for a fraction of fast rotating BSSs, with a mild peak within one core radius, and a possible rise in the external regions (beyond four core radii). This may suggest that recent formation episodes of mass transfer BSSs occurred preferentially in the outskirts of ω Centauri, or that braking mechanisms able to slow down these stars are least efficient in the lowest density environments.

  18. Weighing stars: the identification of an Evolved Blue Straggler Star in the globular cluster 47 Tucanae

    CERN Document Server

    Ferraro, F R; Mucciarelli, A; Lanzoni, B; Dalessandro, E; Pallanca, C; Massari, D

    2015-01-01

    Globular clusters are known to host peculiar objects, named Blue Straggler Stars (BSSs), significantly heavier than the normal stellar population. While these stars can be easily identified during their core hydrogen-burning phase, they are photometrically indistinguishable from their low-mass sisters in advanced stages of the subsequent evolution. A clear-cut identification of these objects would require the direct measurement of the stellar mass. We used the detailed comparison between chemical abundances derived from neutral and from ionized spectral lines as a powerful stellar "weighing device" to measure stellar mass and to identify an evolved BSS in 47 Tucanae. In particular, high-resolution spectra of three bright stars located slightly above the level of the "canonical" horizontal branch sequence in the color-magnitude diagram of 47 Tucanae, have been obtained with UVES spectrograph. The measurements of iron and titanium abundances performed separately from neutral and ionized lines reveal that two ta...

  19. Spectroscopy of Blue Stragglers and Turnoff Stars in M67 (NGC 2682)

    CERN Document Server

    Shetrone, M; Shetrone, Matthew; Sandquist, Eric

    2000-01-01

    We have analyzed high-resolution spectra of relatively cool blue stragglers and main sequence turnoff stars in the old open cluster M67 (NGC 2682). We attempt to identify blue stragglers whose spectra are least contaminated by binary effects (contamination by a binary companion or absorption by circumstellar material). These ``best'' stragglers have metallicities ([Fe/H] = -0.05) and abundance ratios of the blue stragglers are not significantly different from those of the turnoff stars. Based on arguments from hydrodynamical models of stellar collisions, we assert that the current upper limits for the lithium abundances of all blue stragglers observed in M67 (by us and others) are consistent with no mixing during the formation process, assuming pre-main sequence and main sequence depletion patterns observed for M67 main sequence stars. We discuss composition signatures that could more definitively distinguish between blue straggler formation mechanisms in open cluster stars. We confirm the spectroscopic detec...

  20. Spinning like a Blue Straggler: the population of fast rotating Blue Straggler stars in Omega Centauri

    CERN Document Server

    Mucciarelli, A; Ferraro, F R; Dalessandro, E; Lanzoni, B; Monaco, L

    2014-01-01

    By using high-resolution spectra acquired with FLAMES-GIRAFFE at the ESO/VLT, we measured radial and rotational velocities for 110 Blue Straggler stars (BSSs) in Omega Centauri, the globular cluster-like stellar system harboring the largest known BSS population. According to their radial velocities, 109 BSSs are members of the system. The rotational velocity distribution is very broad, with the bulk of BSSs spinning at less than ~40 km/s (in agreement with the majority of such stars observed in other globular clusters) and a long tail reaching ~200 km/s. About 40% of the sample has vsini >40 km/s and about 20% has vsini >70 km/s. Such a large fraction is very similar to the percentage of of fast rotating BSSs observed in M4. Thus, Omega Centauri is the second stellar cluster, beyond M4, with a surprisingly high population of fast spinning BSSs. We found a hint of a radial behaviour of the fraction of fast rotating BSSs, with a mild peak within one core radius, and a possibile rise in the external regions (bey...

  1. Revealing the nature of star forming blue early-type galaxies at low redshift

    CERN Document Server

    George, Koshy

    2015-01-01

    Context: Star forming early-type galaxies with blue optical colours at low redshift can be used to test our current understanding of galaxy formation and evolution. Aims: We want to reveal the fuel and triggering mechanism for star formation in these otherwise passively evolving red and dead stellar systems. Methods: We undertook an optical and ultraviolet study of 55 star forming blue early-type galaxies, searching for signatures of recent interactions that could be driving the molecular gas into the galaxy and potentially triggering the star formation. Results: We report here our results on star forming blue early-type galaxies with tidal trails and in close proximity to neighbouring galaxies that are evidence of ongoing or recent interactions between galaxies. There are 12 galaxies with close companions with similar redshifts, among which two galaxies are having ongoing interactions that potentially trigger the star formation. Two galaxies show a jet feature that could be due to the complete tidal disrupti...

  2. Revealing the nature of star forming blue early-type galaxies at low redshift

    Science.gov (United States)

    George, Koshy; Zingade, Kshama

    2015-11-01

    Context. Star forming early-type galaxies with blue optical colours at low redshift can be used to test our current understanding of galaxy formation and evolution. Aims: We want to reveal the fuel and triggering mechanism for star formation in these otherwise passively evolving red and dead stellar systems. Methods: We undertook an optical and ultraviolet study of 55 star forming blue early-type galaxies, searching for signatures of recent interactions that could be driving the molecular gas into the galaxy and potentially triggering the star formation. Results: We report here our results on star forming blue early-type galaxies with tidal trails and in close proximity to neighbouring galaxies that are evidence of ongoing or recent interactions between galaxies. There are 12 galaxies with close companions with similar redshifts, among which two galaxies are having ongoing interactions that potentially trigger the star formation. Two galaxies show a jet feature that could be due to the complete tidal disruption of the companion galaxy. The interacting galaxies have high star formation rates and very blue optical colours. Galaxies with no companion could have undergone a minor merger in the recent past. Conclusions: The recent or ongoing interaction with a gas-rich neighbouring galaxy could be responsible for bringing cold gas to an otherwise passively evolving early-type galaxy. The sudden gas supply could trigger the star formation, eventually creating a blue early-type galaxy. The galaxies with ongoing tidal interaction are blue and star forming, thereby implying that blue early-type galaxies can exist even when the companion is on flyby so does not end up in a merger. Based on data compiled from Galaxy Zoo project, and the volunteers contribution are acknowledged at http://www.galaxyzoo.org/Volunteers.aspx

  3. Tracing the star formation history of three Blue Compact galaxies through the analysis of their star clusters

    CERN Document Server

    Adamo, Angela; Zackrisson, Erik; Hayes, Matthew

    2009-01-01

    We present preliminary results from a study of the compact star cluster populations in three local luminous blue compact galaxies: ESO 185-IG 013, ESO 350-IG 038 (a.k.a. Haro 11), and MRK 930. These systems show peculiar morphologies and the presence of hundreds of SCs that have been produced by the past, recent, and/or current starburst phases. We use a complete set of HST images ranging from the UV to IR for each galaxy. Deep images in V (WFPC2/f606w) and I (WFPC2/f814w) are used to capture most of the star cluster candidates up to the old ones (fainter) which have had, in the past, less possibility to be detected. The other bands are used in the SED fitting technique for constraining ages and masses. Our goals are to investigate the evolution of these three blue compact galaxies and the star cluster formation impact on their star formation history.

  4. Weighing Stars: The Identification of an Evolved Blue Straggler Star in the Globular Cluster 47 Tucanae

    Science.gov (United States)

    Ferraro, F. R.; Lapenna, E.; Mucciarelli, A.; Lanzoni, B.; Dalessandro, E.; Pallanca, C.; Massari, D.

    2016-01-01

    Globular clusters are known to host peculiar objects named blue straggler stars (BSSs), significantly heavier than the normal stellar population. While these stars can be easily identified during their core hydrogen-burning phase, they are photometrically indistinguishable from their low-mass sisters in advanced stages of the subsequent evolution. A clear-cut identification of these objects would require the direct measurement of the stellar mass. We used the detailed comparison between chemical abundances derived from neutral and from ionized spectral lines as a powerful stellar “weighing device” to measure stellar mass and to identify an evolved BSS in 47 Tucanae. In particular, high-resolution spectra of three bright stars, located slightly above the level of the “canonical” horizontal branch (HB) sequence in the color-magnitude diagram of 47 Tucanae, have been obtained with the UVES spectrograph. The measurements of iron and titanium abundances performed separately from neutral and ionized lines reveal that two targets have stellar parameters fully consistent with those expected for low-mass post-HB objects, while for the other target the elemental ionization balance is obtained only by assuming a mass of ˜ 1.4{M}⊙ , which is significantly larger than the main sequence turn-off mass of the cluster (˜ 0.85{M}⊙ ). The comparison with theoretical stellar tracks suggests that this is a BSS descendant possibly experiencing its core helium-burning phase. The large applicability of the proposed method to most of the globular clusters in our Galaxy opens the possibility to initiate systematic searches for evolved BSSs, thus giving access to still unexplored phases of their evolution. Based on UVES-FLAMES observations collected under Program 193.D-0232.

  5. Ultra-Lithium-Deficient Halo Stars and Blue Stragglers A Common Origin?

    CERN Document Server

    Ryan, S G; Kajino, T; Rosolankova, K; Ryan, Sean G.; Beers, Timothy C.; Kajino, Toshitaka; Rosolankova, Katarina

    2000-01-01

    We present data for four ultra-Li-deficient, warm, halo stars. The Li deficiency of two of these is a new discovery. Three of the four stars have effective temperatures Teff ~ 6300 K, in contrast to previously known Li-deficient halo stars which spanned the temperature range of the Spite Plateau. In this paper we propose that these, and previously known ultra-Li-deficient halo stars, may have had their surface lithium abundances reduced by the same mechanism as produces halo field blue stragglers. Even though these stars have yet to reveal themselves as blue stragglers, they might be regarded as "blue-stragglers-to-be." In our proposed scenario, the surface abundance of Li in these stars could be destroyed (a) during the normal pre-main-sequence single star evolution of their low mass precursors, (b) during the post-main-sequence evolution of a evolved mass donor, and/or (c) via mixing during a mass-transfer event or stellar merger. The warmest Li-deficient stars at the turnoff would be regarded as emerging "...

  6. BLUE LUMINOUS STARS IN NEARBY GALAXIES-UIT 005: A POSSIBLE LINK TO THE LUMINOUS BLUE VARIABLE STAGE

    International Nuclear Information System (INIS)

    A detailed study of the blue supergiant UIT 005 (B2-2.5Ia+) in M 33 is presented. The results of our quantitative spectral analysis indicate that the star is a very luminous (log L/Lsun ∼ 5.9 dex) and massive (M ∼ 50 Msun) object, showing a very high nitrogen-to-oxygen ratio in its surface (N/O∼8, by mass). Based on the derived Mg and Si abundances, we argue that this high N/O ratio cannot be the result of an initial low O content due to its location on the disk of M 33, a galaxy known to present a steep metallicity gradient. In combination with the He abundance, the most plausible interpretation is that UIT 005 is in an advanced stage of evolution, showing in its surface N enrichment and O depletion resulting from mixing with CNO processed material from the stellar interior. A comparison with the predictions of current stellar evolutionary models indicates that there are significant discrepancies, in particular with regard to the degree of chemical processing, with the models predicting a much lower degree of O depletion than observed. At the same time, the mass-loss rate derived in our analysis is an order of magnitude lower than the values considered in the evolutionary calculations. Based on a study of the surrounding stellar population and the nearby cluster, NGC 588, using Hubble Space Telescope/WFPC2 photometry, we suggest that UIT 005 could be in fact a runaway star from this cluster. Regardless of its origin, the derived parameters place the star in a region of the Hertzsprung-Russell diagram where luminous blue variables (LBVs) are usually found, but we find no evidence supporting photometric or spectroscopic variability, except for small Hα changes, otherwise observed in Galactic B-type supergiants. Whether UIT 005 is an LBV in a dormant state or a regular blue supergiant could not be discerned in this study. Subsequent monitoring would help us to improve our knowledge of the more massive stars, bridging the gap between regular and more exotic

  7. Cannibals in the thick disk: the young $\\alpha-$rich stars as evolved blue stragglers

    CERN Document Server

    Jofre, P; Izzard, R G; Van Eck, S; Hawkins, K; Jorissen, A; Gilmore, G; Paladini, C

    2016-01-01

    Spectro-seismic measurements of red giant stars enabled the recent discovery of giant stars in the thick disk that are more massive than 1.4 M_sun (Martig et al 2015, Chiappini et al 2015). While it has been claimed that most of these stars are younger than the rest of the typical thick disk stars, we show evidence that they might be products of mass transfer in binary evolution, notably evolved blue stragglers. We took new measurements of the radial velocities in a sample of 26 stars from APOKASC, including 13 of the "young" stars of Martig et al (2015) and 13 "old" stars with similar stellar parameters but with masses below 1 M_sun and found that some stars are in binary systems, contrary to what has been claimed before. Furthermore, with a population synthesis of only low-mass stars but including binary evolution and mass transfer, we can reproduce the masses and the [C/N] ratios of the 26 stars. Our study shows how asteroseismology of solar-type red giants provides us with a unique opportunity to study th...

  8. The different star-formation histories of blue and red spiral and elliptical galaxies

    CERN Document Server

    Tojeiro, Rita; Richards, Joshua; Percival, Will J; Bamford, Steven P; Maraston, Claudia; Nichol, Robert C; Skibba, Ramin; Thomas, Daniel

    2013-01-01

    [Abridged] We study the spectral properties of intermediate mass galaxies as a function of colour and morphology. We use Galaxy Zoo to define three morphological classes of galaxies, namely early-types (ellipticals), late-type (disk-dominated) face-on spirals and early-type (bulge-dominated) face-on spirals. We classify these galaxies as blue or red according to their SDSS g-r colour and use the spectral fitting code VESPA to calculate time-resolved star-formation histories, metallicity and total starlight dust extinction from their SDSS fibre spectra. We find that red late-type spirals show less star-formation in the last 500 Myr than blue late-type spirals by up to a factor of three, but share similar star-formation histories at earlier times. This decline in recent star-formation explains their redder colour: their chemical and dust content are the same. We postulate that red late-type spirals are recent descendants of blue late-type spirals, with their star-formation curtailed in the last 500 Myrs. The re...

  9. Spectroscopy of blue horizontal branch stars in NGC 6656 (M22)

    CERN Document Server

    Salgado, C; Villanova, S; Geisler, D; Catelan, M

    2013-01-01

    Recent investigations revealed very peculiar properties of blue horizontal branch (HB) stars in \\omega Centauri, which show anomalously low surface gravity and mass compared to other clusters and to theoretical models. \\omega Centauri, however, is a very unusual object, hosting a complex mix of multiple stellar populations with different metallicity and chemical abundances. We measured the fundamental parameters (temperature, gravity, and surface helium abundance) of a sample of 71 blue HB stars in M22, with the aim of clarifying if the peculiar results found in \\omega Cen are unique to this cluster. M22 also hosts multiple sub-populations of stars with a spread in metallicity, analogous to \\omega Cen. The stellar parameters were measured on low-resolution spectra fitting the Balmer and helium lines with a grid of synthetic spectra. From these parameters, the mass and reddening were estimated. Our results on the gravities and masses agree well with theoretical expectations, matching the previous measurements ...

  10. Two distinct sequences of blue straggler stars in the globular cluster M30

    CERN Document Server

    Ferraro, F R; Dalessandro, E; Lanzoni, B; Sills, A; Rood, R T; Pecci, F Fusi; Karakas, A I; Miocchi, P; Bovinelli, S; 10.1038/nature08607

    2010-01-01

    Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history. 'Blue stragglers' are stars massive enough that they should have evolved into white dwarfs long ago. Two possible mechanisms have been proposed for their formation: mass transfer between binary companions and stellar mergers resulting from direct collisions between two stars. Recently, the binary explanation was claimed to be dominant. Here we report that there are two distinct parallel sequences of blue stragglers in M30. This globular cluster is thought to have undergone 'core collapse', during which both the collision rate and the mass transfer activity in binary systems would have been enhanced. We suggest that the two observed sequences arise from the cluster core collapse, with the bluer population arising from direct stellar collisions and the redder one arising from the evolution of close binaries that are probably still experiencing an active phase of mass transfer.

  11. GAS MASS FRACTIONS AND STAR FORMATION IN BLUE-SEQUENCE E/S0 GALAXIES

    International Nuclear Information System (INIS)

    Recent work has identified a population of low-redshift E/S0 galaxies that lie on the blue sequence in color versus stellar mass parameter space, where spiral galaxies typically reside. While high-mass blue-sequence E/S0s often resemble young merger or interaction remnants likely to fade to the red sequence, we focus on blue-sequence E/S0s with lower stellar masses (M*10 Msun), which are characterized by fairly regular morphologies and low-density field environments where fresh gas infall is possible. This population may provide an evolutionary link between early-type galaxies and spirals through disk regrowth. Focusing on atomic gas reservoirs, we present new GBT H I data for 27 E/S0s on both sequences as well as a complete tabulation of archival H I data for other galaxies in the Nearby Field Galaxy Survey. Normalized to stellar mass, the atomic gas masses for 12 of the 14 blue-sequence E/S0s range from 0.1 to >1.0, demonstrating that morphological transformation is possible if the detected gas can be converted into stars. These gas-to-stellar mass ratios are comparable to those of spiral and irregular galaxies and have a similar dependence on stellar mass. Assuming that the H I is accessible for star formation, we find that many of our blue-sequence E/S0s can increase in stellar mass by 10%-60% in 3 Gyr in both of two limiting scenarios, exponentially declining star formation (i.e., closed box) and constant star formation (i.e., allowing gas infall). In a constant star formation scenario, about half of the blue-sequence E/S0s require fresh gas infall on a timescale of ∼<3 Gyr to avoid exhausting their atomic gas reservoirs and evolving to the red sequence. We present evidence that star formation in these galaxies is bursty and likely involves externally triggered gas inflows. Our analysis suggests that most blue-sequence E/S0s are indeed capable of substantial stellar disk growth on relatively short timescales.

  12. Spectroscopic observations of blue stars with infrared excesses in NGC 6611

    CERN Document Server

    Bonito, R; Guarcello, M G; Micela, G

    2013-01-01

    The young open cluster NGC 6611 includes among its candidate members a class of peculiar objects with interesting properties: blue stars with infrared IR excesses. These stars show excesses in IR bands, signature of the presence of a circumstellar disk, but optical colors typical of older field stars. In order to confirm their membership to the cluster, it is therefore important to use new spectroscopic observations, together with previous photometric data. We aim at confirming the membership of these objects and at investigating their physical properties to verify whether the observed colors are intrinsic or altered by the presence of the disk or by the accretion processes. We analyze the intermediate resolution spectroscopic data obtained for a subsample of blue stars in NGC 6611 with FLAMES. In particular, we focus on the study of: 1) the profile of the Ha emission line, to select stars with accretion and outflow activity; 2) the Li absorption line, used as a youth indicator; 3) the radial velocity. Using ...

  13. Hyperbranched polymer-cored star polyfluorenes as blue light-emitting materials

    Institute of Scientific and Technical Information of China (English)

    HAN Yang; SUN MingHao; FEI ZhuPing; BO ZhiShan

    2008-01-01

    Hyperbranched polymer-cored star polyfluorenes with high molecular weights and narrow molecular weight distribution were prepared by palladium-catalyzed one-pot Suzuki polycondensation of multi-functional cores and an AB-type monomer. The optical, electrochemical and thermal properties of the hyperbranched polymer-cored star polymers were investigated. These polymers exhibited good ther-mal and color stability in solid state, and there was no significant blue-green emission after the poly-mers had been annealed in air for 2.5 h. Their three-dimensional hyperbranched structures could ef-fectively reduce the aggregation of the peripheral rigid linear conjugated polyfluorene chains.

  14. The Chemical Compositions of Non-Variable Red and Blue Field Horizontal Branch Stars

    CERN Document Server

    For, Bi-Qing

    2010-01-01

    We present a new detailed abundance study of field red horizontal branch (RHB) and blue horizontal branch (BHB) non-variable stars. High resolution and high S/N echelle spectra of 11 RHB and 12 BHB were obtained with the McDonald 2.7 m telescope, and the RHB sample was augmented by reanalysis of spectra of 25 stars from a recent survey. We derived stellar atmospheric parameters based on spectroscopic constraints, and computed relative abundance ratios for 24 species of 19 elements. The species include Si II and Ca II, which have not been previously studied in RHB and BHB (Teff ~ [Fe/H] >~ -2.5. This yielded effective temperatures estimates of 5900K and 7400 K for the red and blue edges of the RR Lyrae instability strip.

  15. Striking Photospheric Abundance Anomalies in Blue Horizontal-Branch Stars in Globular Cluster M13

    CERN Document Server

    Behr, B B; McCarthy, J K; Djorgovski, S G; Behr, Bradford B.; Cohen, Judith G.; Carthy, James K. Mc

    1999-01-01

    High-resolution optical spectra of thirteen blue horizontal-branch (BHB) stars in the globular cluster M13 show enormous deviations in element abundances from the expected cluster metallicity. In the hotter stars (T_eff > 12000 K), helium is depleted by factors of 10 to 100 below solar, while iron is enhanced to three times the solar abundance, two orders of magnitude above the canonical metallicity [Fe/H] ~= -1.5 dex for this globular cluster. Nitrogen, phosphorus, and chromium exhibit even more pronounced enhancements, and other metals are also mildly overabundant, with the exception of magnesium, which stays very near the expected cluster metallicity. These photospheric anomalies are most likely due to diffusion --- gravitational settling of helium, and radiative levitation of the other elements --- in the stable radiative atmospheres of these hot stars. The effects of these mechanisms may have some impact on the photometric morphology of the cluster's horizontal branch and on estimates of its age and dist...

  16. Investigating mass segregation process in globular clusters with Blue Straggler Stars: the impact of dark remnants

    CERN Document Server

    Alessandrini, Emiliano; Ferraro, Francesco Rosario; Miocchi, Paolo; Vesperini, Enrico

    2016-01-01

    We present the results of a set of N-body simulations aimed at exploring how the process of mass segregation (as traced by the spatial distribution of blue straggler stars, BSSs) is affected by the presence of a population of heavy dark remnants (as neutron stars and black holes). To this end, clusters characterized by different initial concentrations and different fractions of dark remnants have been modeled. We find that an increasing fraction of stellar-mass black holes significantly delays the mass segregation of BSSs and the visible stellar component. In order to trace the evolution of BSS segregation, we introduce a new parameter ($A^+$) that can be easily measured when the cumulative radial distribution of these stars and a reference population are available. Our simulations show that $A^+$ might also be used as an approximate indicator of the time remaining to the core collapse of the visible component.

  17. Chemical Abundances and Rotation Velocities of Blue Horizontal-Branch Stars in Six Globular Clusters

    CERN Document Server

    Behr, B B

    2003-01-01

    High-resolution spectroscopic measurements of blue horizontal-branch stars in six metal-poor globular clusters -- M3, M13, M15, M68, M92, and NGC 288 -- reveal remarkable variations in photospheric composition and rotation velocity as a function of a star's position along the horizontal branch. For the cooler stars (Teff < 11200 K), the derived abundances are in good agreement with the canonical cluster metallicities, and we find a wide range of v sin i rotation velocities, some as high as 40 km/s. In the hotter stars, however, most metal species are strongly enhanced, by as much as 3 dex, relative to the expected cluster metallicity, while helium is depleted by 2 dex or more. In addition, the hot stars all rotate slowly, with v sin i < 8 km/s. The anomalous abundances appear to be due to atomic diffusion mechanisms -- gravitational settling of helium, and radiative levitation of metals -- in the non-convective atmospheres of these hot stars. We discuss the influence of these photospheric metal enhancem...

  18. Chronography of the Milky Way's Halo System with Field Blue Horizontal-Branch Stars

    CERN Document Server

    Santucci, R M; Placco, V M; Carollo, D; Rossi, S; Lee, Y S; Denissenkov, P; Tumlinson, J; Tissera, P B

    2015-01-01

    In a pioneering effort, Preston et al. reported that the colors of blue horizontal-branch (BHB) stars in the halo of the Galaxy shift with distance, from regions near the Galactic center to about 12 kpc away, and interpreted this as a correlated variation in the ages of halo stars, from older to younger, spanning a range of a few Gyrs. We have applied this approach to a sample of some 4700 spectroscopically confirmed BHB stars selected from the Sloan Digital Sky Survey to produce the first "chronographic map" of the halo of the Galaxy. We demonstrate that the mean de-reddened g$-$r color, , increases outward in the Galaxy from $-$0.22 to $-$0.08 (over a color window spanning [$-$0.3:0.0]) from regions close to the Galactic center to ~40 kpc, independent of the metallicity of the stars. Models of the expected shift in the color of the field BHB stars based on modern stellar evolutionary codes confirm that this color gradient can be associated with an age difference of roughly 2-2.5 Gyrs, with the oldest stars ...

  19. Vertical stratification of iron in atmospheres of blue horizontal-branch stars

    CERN Document Server

    Khalack, V; Behr, B B

    2010-01-01

    The aim of this study is to search for observational evidence of vertical iron stratification in the atmosphere of fourteen blue horizontal-branch (BHB) stars. We have found from our numerical simulations that five BHB stars: B22, B186 in the globular cluster NGC 288, WF2-820, WF2-2692 in M13 and B203 in M15 show clear signatures of the vertical stratification of iron whose abundance increases toward the lower atmosphere. Two other BHB stars (B334 in M15 and B176 in M92) also show possible iron stratification in their atmosphere. A dependence of the slope of iron stratification on the effective temperature was also discovered. It is found that the vertical stratification of iron is strongest in BHB stars with Teff around 11,500K. The slope of iron abundance decreases as Teff increases and becomes negligible for the BHB stars with Teff= 14,000K. These results support the hypothesis regarding the efficiency of atomic diffusion in the stellar atmospheres of BHB stars with Teff > 11,500K.

  20. FROM BLUE STAR-FORMING TO RED PASSIVE: GALAXIES IN TRANSITION IN DIFFERENT ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Vulcani, Benedetta [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, the University of Tokyo, Kashiwa 277-8582 (Japan); Poggianti, Bianca M.; Fasano, Giovanni; Moretti, Alessia [INAF-Astronomical Observatory of Padova, I-35122 Padova (Italy); Fritz, Jacopo [Sterrenkundig Observatorium Vakgroep Fysica en Sterrenkunde Universiteit Gent, Krijgslaan 281, S9 B-9000 Gent (Belgium); Calvi, Rosa; Paccagnella, Angela [Dipartimento di Fisica e Astronomia, Universitá degli Studi di Padova, vicolo Osservatorio 2, I-35122 Padova (Italy)

    2015-01-01

    Exploiting a mass-complete (M {sub *} > 10{sup 10.25} M {sub ☉}) sample at 0.03 star-formation activity and/or morphology: green galaxies, red passive late types, and blue star-forming early types. Color fractions depend on mass and only for M {sub *} < 10{sup 10.7} M {sub ☉} on environment. The incidence of red galaxies increases with increasing mass, and, for M {sub *} < 10{sup 10.7} M {sub ☉}, decreases toward the group outskirts and in binary and single galaxies. The relative abundance of green and blue galaxies is independent of environment and increases monotonically with galaxy mass. We also inspect galaxy structural parameters, star-formation properties, histories, and ages and propose an evolutionary scenario for the different subpopulations. Color transformations are due to a reduction and suppression of the star-formation rate in both bulges and disks that does not noticeably affect galaxy structure. Morphological transitions are linked to an enhanced bulge-to-disk ratio that is due to the removal of the disk, not to an increase of the bulge. Our modeling suggests that green colors might be due to star-formation histories declining with long timescales, as an alternative scenario to the classical ''quenching'' processes. Our results suggest that galaxy transformations in star-formation activity and morphology depend neither on the environment nor on being a satellite or the most massive galaxy of a halo. The only environmental dependence we find is the higher fast quenching efficiency in groups giving origin to poststarburst signatures.

  1. The Stellar Population and Star Formation Properties of Blue Compact Dwarf Galaxies

    CERN Document Server

    Zhao, Yinghe; Gao, Yu

    2010-01-01

    We study the stellar populations, star formation histories and star formation properties for a sample of blue compact dwarf galaxies (BCDs) selected by cross-correlating the Gil de Paz et al. (2003) sample with the Sloan Digital Sky Survey Data Release 6 (SDSS DR6). The sample includes 31 BCDs, which span a large range in galactic parameters. Using a stellar population synthesis method, we derive the stellar populations and reconstruct the star formation histories for these BCDs. Our studies confirm that BCDs are not young systems experiencing their first star formation but old systems undergoing a starburst activity. The stellar mass-weighted ages can be as old as 10 Gyr while the luminosity-weighted ages might be up to $\\sim 3$ orders of magnitude younger ($\\sim 10$ Myr) for most galaxies. Based on multi-wavelength data, we also study the integrated star formation properties. The SFR for our sample galaxies spans nearly 3 orders of magnitude, from a few $10^{-3}$ to $\\sim1\\,M_\\odot$ yr$^{-1}$, with the medi...

  2. THE STELLAR POPULATION AND STAR FORMATION PROPERTIES OF BLUE COMPACT DWARF GALAXIES

    International Nuclear Information System (INIS)

    We study stellar populations, star formation histories (SFHs), and star formation properties for a sample of blue compact dwarf galaxies (BCDs) selected by cross-correlating the Gil de Paz et al. sample with the Sloan Digital Sky Survey Data Release 6. The sample includes 31 BCDs, which span a large range of galactic parameters. Using a stellar population synthesis method, we derive stellar populations and reconstruct SFHs for these BCDs. Our studies confirm that BCDs are not young systems experiencing their first star formation, but old systems undergoing a starburst activity. The stellar mass-weighted ages can be up to 10 Gyr, while the luminosity-weighted ages might be up to approximately three orders of magnitude younger (∼10 Myr) for most galaxies. Based on multiwavelength data, we also study the integrated star formation properties. The star formation rate (SFR) for our sample galaxies spans nearly three orders of magnitude, from a few 10-3 to ∼1 Msun yr-1, with a median value of ∼0.1 Msun yr-1. We find that about 90% of BCDs in our sample have their birthrate parameter (the ratio of the current SFR to the averaged past SFR) b>2-3. We further discuss correlations of the current SFR with the integrated galactic stellar mass and explore the connection between SFR and metallicity.

  3. From blue star-forming to red passive: galaxies in transition in different environments

    CERN Document Server

    Vulcani, Benedetta; Fritz, Jacopo; Fasano, Giovanni; Moretti, Alessia; Calvi, Rosa; Paccagnella, Angela

    2014-01-01

    Exploiting a mass complete (M_*>10^(10.25)M_sun) sample at 0.03star formation activity and/or morphology - green galaxies, red passive late types, and blue star-forming early types. Color fractions depend on mass and only for M_*<10^(10.7)M_sun on environment. The incidence of red galaxies increases with increasing mass, and, for M_*<10^(10.7)M_sun, decreases toward the group outskirts and in binary and single galaxies. The relative abundance of green and blue galaxies is independent of environment, and increases monotonically with galaxy mass. We also inspect galaxy structural parameters, star-formation properties, histories and ages and propose an evolutionary scenario for the different subpopulations. Color transformations are due to a reduction and suppression of SFR in bot...

  4. Blue straggler star populations in globular clusters. I. Dynamical properties of blue straggler stars in NGC 3201, NGC 6218, and ω Centauri

    Energy Technology Data Exchange (ETDEWEB)

    Simunovic, Mirko; Puzia, Thomas H., E-mail: msimunov@astro.puc.cl, E-mail: tpuzia@astro.puc.cl [Institute of Astrophysics, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago (Chile)

    2014-02-10

    We present the first dynamical study of blue straggler stars (BSSs) in three Galactic globular clusters, NGC 3201, NGC 5139 (ω Cen), and NGC 6218, based on medium-resolution spectroscopy (R ≈ 10, 000) obtained with the Inamori-Magellan Areal Camera and Spectrograph mounted at the 6.5 m Baade Magellan telescope. Our BSS candidate selection technique uses HST/ACS and ESO/WFI photometric data out to >4.5 r{sub c} . We use radial velocity measurements to discard non-members and achieve a success rate of ∼93%, which yields a sample of 116 confirmed BSSs. Using the penalized pixel-fitting method (pPXF), we measure the vsin (i) values of the sample BSSs and find their distribution functions peaked at slow velocities with a long tail toward fast velocities in each globular cluster. About 90% of the BSS population in NGC 3201 and NGC 6218 exhibits values in the range 10-50 km s{sup –1}, while about 80% of the BSSs in ω Cen show vsin (i) values between 20 and 70 km s{sup –1}. We find that the BSSs in NGC 3201 and NGC 6218 that show vsin (i) > 50 km s{sup –1} are all found in the central cluster regions, inside a projected 2r{sub c} , of their parent clusters. We find a similar result in ω Cen for BSSs with vsin (i) > 70 km s{sup –1}, which are all, except for two, concentrated inside 2r{sub c} . In all globular clusters, we find rapidly rotating BSSs that have relatively high differential radial velocities that likely put them on hyperbolic orbits, suggestive of strong dynamical interactions in the past. Based on stellar spin-down and dynamical crossing timescales, we estimate that all the observed rapidly rotating BSSs are likely to form in their central cluster regions no longer than ∼300 Myr ago and may be subsequently ejected from their host globular clusters. Using dereddened V – I colors of our photometric selection, we show that blue BSSs in ω Cen with (V – I){sub 0} ≲ 0.25 mag show a significantly increased vsin (i) dispersion compared with

  5. Study of the luminous blue variable star candidate G26.47+0.02 and its environment

    OpenAIRE

    Paron, S.; Combi, J. A.; Petriella, A.; Giacani, E.

    2012-01-01

    The luminous blue variable (LBV) stars are peculiar very massive stars. The study of these stellar objects and their surroundings is important for understanding the evolution of massive stars and its effects on the interstellar medium. We study the LBV star candidate G26.47+0.02. Using several large-scale surveys in different frequencies we performed a multiwavelength study of G26.47+0.02 and its surroundings. We found a molecular shell (seen in the 13CO J=1-0 line) that partially surrounds t...

  6. Stellar Encounters with Multiple Star Systems and the Blue Straggler Problem

    CERN Document Server

    Leigh, Nathan

    2010-01-01

    We present a technique to identify the most probable dynamical formation scenario for an observed binary or triple system containing one or more merger products or, alternatively, to rule out the possibility of a dynamical origin. Our method relies on an analytic prescription for energy conservation during stellar encounters. With this, observations of the multiple star system containing the merger product(s) can be used to work backwards in order to constrain the initial orbital energies of any single, binary or triple systems that went into the encounter. The initial semi-major axes of the orbits provide an estimate for the collisional cross section and therefore the time-scale for the encounter to occur in its host cluster. We have applied our analytic prescription to observed binary and triple systems containing blue stragglers, in particular the triple system S1082 in M67 and the period distribution of the blue straggler binaries in NGC 188. We have shown that both S1082 and most of the blue straggler bi...

  7. Blue Straggler Star Populations in Globular Clusters: I. Dynamical Properties of Blue Straggler Stars in NGC 3201, NGC 6218 and $\\omega$ Centauri

    CERN Document Server

    Simunovic, Mirko

    2013-01-01

    We present the first dynamical study of Blue Straggler Stars (BSSs) in three Galactic globular clusters, NGC\\,3201, NGC\\,5139 ($\\omega$Cen), and NGC\\,6218, based on medium-resolution spectroscopy (R 10000) obtained with IMACS. Our BSS candidate selection technique uses HST/ACS and ESO/WFI photometric data out to $>\\!4.5\\,r_c$. We use radial velocity measurements to discard non-members and achieve a success rate of $\\sim93\\%$, which yields a sample of 116 confirmed BSSs. Using the penalized pixel fitting method (pPXF) we measure the $v\\sin(i)$ values of the sample BSSs and find their distribution functions peaked at slow velocities with a long tail towards fast velocities in each globular cluster. We find that the BSSs in NGC\\,3201 and NGC\\,6218 which show $v\\sin(i)\\!>\\!50$ km s$^{-1}$ are all found in the central cluster regions, inside a projected $2\\,r_c$, of their parent clusters. We find a similar result in $\\omega$Cen for BSSs with $v\\sin(i)\\!>\\!70$ km s$^{-1}$ which are all, except for two, concentrated...

  8. Vertical abundance stratification in the blue horizontal branch star HD135485

    CERN Document Server

    Khalack, V R; Bohlender, D A; Wade, G A; Behr, B B

    2007-01-01

    It is commonly believed that the observed overabundances of many chemical species relative to the expected cluster metallicity in blue horizontal branch (BHB) stars appear as a result of atomic diffusion in the photosphere. The slow rotation of BHB stars (with T_eff > 11,500K), typically v sin{i} < 10 km/s, is consistent with this idea. In this work we search for observational evidence of vertical chemical stratification in the atmosphere of HD135485. If this evidence exists, it will demonstrate the importance of atomic diffusion processes in the atmospheres of BHB stars. We undertake an extensive abundance stratification analysis of the atmosphere of HD135485, based on recently acquired high resolution and S/N CFHT ESPaDOnS spectra and a McDonald-CE spectrum. Our numerical simulations show that nitrogen and sulfur reveal signatures of vertical abundance stratification in the stellar atmosphere. It appears that the abundances of these elements increase toward the upper atmosphere. This fact cannot be expla...

  9. Characterizing stellar halo populations II: The age gradient in blue horizontal-branch stars

    CERN Document Server

    Das, Payel; Binney, James

    2016-01-01

    The distribution of Milky Way halo blue horizontal-branch (BHB) stars is examined using action-based extended distribution functions (EDFs) that describe the locations of stars in phase space, metallicity, and age. The parameters of the EDFs are fitted using stars observed in the Sloan Extension for Galactic Understanding and Exploration-II (SEGUE-II) survey that trace the phase-space kinematics and chemistry out to ~70 kpc. A maximum a posteriori probability (MAP) estimate method and a Markov Chain Monte Carlo method are applied, taking into account the selection function in positions, distance, and metallicity for the survey. The best-fit EDF declines with actions less steeply at actions characteristic of the inner halo than at the larger actions characteristic of the outer halo, and older ages are found at smaller actions than at larger actions. In real space, the radial density profile steepens smoothly from -2 at ~2 kpc to -4 in the outer halo, with an axis ratio ~0.7 throughout. There is no indication f...

  10. Cosmic-Lab: Chemical and kinematical properties of Blue Straggler stars in Galactic Globular Clusters

    CERN Document Server

    Lovisi, L

    2014-01-01

    Blue straggler stars (BSSs) are brighter and bluer than the main-sequence (MS) turnoff and more massive than MS stars.Two scenarios for their formation have been proposed: collision-induced stellar mergers (COL-BSSs),or mass-transfer in binary systems (MT-BSSs).Depleted surface abundances of C and O are expected for MT-BSSs,whereas no chemical anomalies are predicted for COL-BSSs. Both MT and COL-BSSs should rotate fast,but braking mechanisms may intervene with efficiencies and time-scales unknown,thus preventing a clear prediction of the expected rotational velocities. In this context,an extensive survey is ongoing by using FLAMES@VLT, with the aim to obtain abundance patterns and rotational velocities for representative samples of BSSs in Galactic GCs.A sub-population of CO-depleted BSSs has been identified in 47 Tuc,with only one fast rotating star detected (Ferraro et al.2006). For this PhD Thesis work I analyzed FLAMES spectra of more than 130 BSSs in 4 GCs:M4,NGC 6397,M30 and {\\omega}Centauri.This is th...

  11. The supergiant B[e] star LHA 115-S 18 - binary and/or luminous blue variable?

    CERN Document Server

    Clark, J S; Coe, M J; Dorda, R; Haberl, F; Lamb, J B; Negueruela, I; Udalski, A

    2013-01-01

    The mechanism by which supergiant (sg)B[e] stars support cool, dense dusty discs/tori and their physical relationship with other evolved, massive stars such as luminous blue variables is uncertain. In order to investigate both issues we have analysed the long term behaviour of the canonical sgB[e] star LHA 115-S 18. We employed the OGLE II-IV lightcurve to search for (a-)periodic variability and supplemented these data with new and historic spectroscopy. In contrast to historical expectations for sgB[e] stars, S18 is both photometrically and spectroscopically highly variable. The lightcurve is characterised by rapid aperiodic `flaring' throughout the 16 years of observations. Changes in the high excitation emission line component of the spectrum imply evolution in the stellar temperature - as expected for luminous blue variables - although somewhat surprisingly, spectroscopic and photometric variability appears not to be correlated. Characterised by emission in low excitation metallic species, the cool circum...

  12. First results from the Edinburgh-Cape faint blue object survey - Normal stars at high galactic latitudes

    Science.gov (United States)

    Kilkenny, D.; O'Donoghue, D.; Stobie, R. S.

    1991-02-01

    A simple analysis using low-dispersion Reticon spectroscopy and Stromgren photometry is presented for a sample of 20 apparently normal early-type stars detected in the Edinburgh-Cape faint blue object survey of high galactic latitudes. Four stars are not normal, showing high gravity or helium abundance anomalies; 12 stars appear to be at moderate distances from the galactic plane and four stars have derived z-distances greater than about 5 kpc. The sample was selected from 33 survey fields completed to B = 16.5 mag and indicates that the total galactic population of 'very high-z' B stars is only of the order 100-1000. The Dyson and Hartquist (1983) model for the formation of such objects by cloudlet-cloudlet collisions within high-velocity clouds cannot therefore be ruled out on the basis of star formation rates.

  13. Atmospheric NLTE-models for the spectroscopic analysis of luminous blue stars with winds.

    Science.gov (United States)

    Santolaya-Rey, A. E.; Puls, J.; Herrero, A.

    1997-07-01

    We present a new, fast and easy to use NLTE line formation code for ``unified atmospheres'' with spherical extension and stellar winds, developed for the (routine) spectroscopic analysis of luminous blue stars, covering the spectral range from ``A'' to ``O'' and including central stars of planetary nebulae. The major features of our code are: Data driven input of atomic models; consistent photospheric stratification including continuum radiative acceleration and photospheric extension; ``β-velocity law'' for the wind; comoving frame or Sobolev plus continuum line transfer; fast solution algorithm for calculating line profiles, allowing for a consistent treatment of incoherent electron scattering. We describe the code and perform thorough tests for models with H/He opacity, especially with respect to a comparison with plane-parallel, hydrostatic models in cases of thin winds. Our conclusions are: Due in particular to our numerical treatment of the radiative transfer in the ionization and recombination integrals, the convergence rate of the solution algorithm is fast. The flux conservation is good, (maximum flux errors of order 2 to 3%), unless the atmospheric conditions are extreme, either with respect to mass-loss or to a large extension of the photosphere. (In these cases, our treatment of the temperature structure has to be improved). A comparison with plane-parallel results shows perfect agreement with the thin wind case. However, this comparison also reveals two interesting effects: First, the strength of the Hei lines in hot O-stars is very sensitive to the treatment of electron scattering in the EUV. This might affect the effective temperature scale of early O spectral types. Second, the effects of photospheric extension become decisive for the gravity determination of stars close to the Eddington limit. Finally, we demonstrate the differences in using the Sobolev vs. the comoving line transfer in the rate equations. We conclude that, in cases of moderate

  14. MOCCA code for star cluster simulations - V. Initial globular cluster conditions influence on blue stragglers

    CERN Document Server

    Hypki, Arkadiusz

    2016-01-01

    The paper presents an analysis of properties of populations of blue stragglers (BSs) in evolving globular clusters, based on numerical simulations done with the MOCCA code for various initial globular clusters conditions. We find that various populations of BSs strongly depend on the initial semi-major axes distributions. With a significant number of compact binaries, the number of evolutionary BSs can be also significant. In turn, for semi-major axes distributions preferring binaries with wider orbits, dynamical BSs are the dominant ones. Their formation scenario is very distinct: for wide binaries the number of dynamical interactions is significantly larger. Most interactions are weak and increase only slightly the eccentricities. However, due to a large number of such interactions, the eccentricities of a number of binaries finally get so large that the stars collide. We study how larger initial clusters' concentrations influence the BSs. Besides the expected increase of the number of dynamically created B...

  15. Model computations of blue stragglers and W UMa-type stars in globular clusters

    CERN Document Server

    Stepien, Kazimierz

    2015-01-01

    It was recently demonstrated that contact binaries occur in globular clusters (GCs) only immediately below turn-off point and in the region of blue straggler stars (BSs). In addition, observations indicate that at least a significant fraction of BSs in these clusters was formed by the binary mass-transfer mechanism. The aim of our present investigation is to obtain and analyze a set of evolutionary models of cool, close detached binaries with a low metal abundance, which are characteristic of GC. We computed the evolution of 975 models of initially detached, cool close binaries with different initial parameters. The models include mass exchange between components as well as mass and angular momentum loss due to the magnetized winds for very low-metallicity binaries with Z = 0.001. The models are interpreted in the context of existing data on contact binary and blue straggler members of GCs. The model parameters agree well with the observed positions of the GC contact binaries in the Hertzsprung-Russell diagra...

  16. Blue Straggler Stars a direct comparison of Star counts and population ratios in six Galactic Globular Clusters

    CERN Document Server

    Ferraro, F R; Rood, R T; Paltrinieri, B; Buonanno, R; Ferraro, Francesco R.; Sills, Alison; Rood, Robert T.; Paltrinieri, Barbara; Buonanno, Roberto

    2003-01-01

    The central regions of six Galactic Globular Clusters (GGCs) (M3, M80, M10, M13, M92 and NGC 288) have been imaged using HST-WFPC2 and the ultraviolet (UV) filters (F255W, F336W). The selected sample covers a large range in both central density and metallicity ([Fe/H]). In this paper, we present a direct cluster-to-cluster comparison of the Blue Stragglers Stars (BSS) population as selected from (m_{255},m_{255}-m_{336}) Color Magnitude Diagrams (CMDs). We have found:(a) BSS in three of the clusters (M3, M80, M92) are much more concentrated toward the center of the cluster than the red giants; because of the smaller BSS samples for the other clusters we can only note that the BSS radial distributions are consistent with central concentration; (b) the specific frequency of BSS varies greatly from cluster to cluster. The most interesting result is that the two clusters with largest BSS specific frequency are at the central density extremes of our sample: NGC 288 (lowest central density) and M80 (highest). This ...

  17. Characterizing stellar halo populations II: The age gradient in blue horizontal-branch stars

    Science.gov (United States)

    Das, Payel; Williams, Angus; Binney, James

    2016-08-01

    The distribution of Milky Way halo blue horizontal-branch (BHB) stars is examined using action-based extended distribution functions (EDFs) that describe the locations of stars in phase space, metallicity, and age. The parameters of the EDFs are fitted using stars observed in the Sloan Extension for Galactic Understanding and Exploration-II (SEGUE-II) survey that trace the phase-space kinematics and chemistry out to ˜70 kpc. A maximum a posteriori probability (MAP) estimate method and a Markov Chain Monte Carlo method are applied, taking into account the selection function in positions, distance, and metallicity for the survey. The best-fit EDF declines with actions less steeply at actions characteristic of the inner halo than at the larger actions characteristic of the outer halo, and older ages are found at smaller actions than at larger actions. In real space, the radial density profile steepens smoothly from -2 at ˜2 kpc to -4 in the outer halo, with an axis ratio ˜0.7 throughout. There is no indication for rotation in the BHBs, although this is highly uncertain. A moderate level of radial anisotropy is detected, with βs varying from isotropic to between ˜0.1 and ˜0.3 in the outer halo depending on latitude. The BHB data are consistent with an age gradient of -0.03 Gyr kpc-1, with some uncertainty in the distribution of the larger ages. These results are consistent with a scenario in which older, larger systems contribute to the inner halo, whilst the outer halo is primarily comprised of younger, smaller systems.

  18. Luminous and variable stars in M31 and M33. II. Luminous blue variables, candidate LBVs, Fe II emission line stars, and other supergiants

    Energy Technology Data Exchange (ETDEWEB)

    Humphreys, Roberta M.; Davidson, Kris [Minnesota Institute for Astrophysics, 116 Church Street SE, University of Minnesota, Minneapolis, MN 55455 (United States); Weis, Kerstin; Bomans, D. J.; Burggraf, Birgitta, E-mail: roberta@umn.edu, E-mail: kweis@astro.rub.de [Astronomical Institute, Ruhr-Universitaet Bochum (Germany)

    2014-07-20

    An increasing number of non-terminal eruptions are being found in the numerous surveys for optical transients. Very little is known about these giant eruptions, their progenitors and their evolutionary state. A greatly improved census of the likely progenitor class, including the most luminous evolved stars, the luminous blue variables (LBVs), and the warm and cool hypergiants is now needed for a complete picture of the final pre-supernova stages of very massive stars. We have begun a survey of the evolved and unstable luminous star populations in several nearby resolved galaxies. In this second paper on M31 and M33, we review the spectral characteristics, spectral energy distributions, circumstellar ejecta, and evidence for mass loss for 82 luminous and variable stars. We show that many of these stars have warm circumstellar dust including several of the Fe II emission line stars, but conclude that the confirmed LBVs in M31 and M33 do not. The confirmed LBVs have relatively low wind speeds even in their hot, quiescent or visual minimum state compared to the B-type supergiants and Of/WN stars which they spectroscopically resemble. The nature of the Fe II emission line stars and their relation to the LBV state remains uncertain, but some have properties in common with the warm hypergiants and the sgB[e] stars. Several individual stars are discussed in detail. We identify three possible candidate LBVs and three additional post-red supergiant candidates. We suggest that M33-013406.63 (UIT301,B416) is not an LBV/S Dor variable, but is a very luminous late O-type supergiant and one of the most luminous stars or pair of stars in M33.

  19. The ages of young star clusters, massive blue stragglers and the upper mass limit of stars: analysing age dependent stellar mass functions

    CERN Document Server

    Schneider, Fabian R N; de Mink, Selma E; Langer, Norbert; Stolte, Andrea; de Koter, Alex; Gvaramadze, Vasilii V; Hußmann, Benjamin; Liermann, Adriane; Sana, Hugues

    2013-01-01

    Massive stars rapidly change their masses through strong stellar winds and mass transfer in binary systems. We show that such mass changes leave characteristic signatures in stellar mass functions of young star clusters which can be used to infer their ages and to identify products of binary evolution. We model the observed present day mass functions of the young Galactic Arches and Quintuplet star clusters using our rapid binary evolution code. We find that shaping of the mass function by stellar wind mass loss allows us to determine the cluster ages to 3.5$\\pm$0.7 Myr and 4.8$\\pm$1.1 Myr, respectively. Exploiting the effects of binary mass exchange on the cluster mass function, we find that the most massive stars in both clusters are rejuvenated products of binary mass transfer, i.e. the massive counterpart of classical blue straggler stars. This resolves the problem of an apparent age spread among the most luminous stars exceeding the expected duration of star formation in these clusters. We perform Monte ...

  20. The Century Survey Galactic Halo Project II: Global Properties and the Luminosity Function of Field Blue Horizontal Branch Stars

    CERN Document Server

    Brown, W R; Kenyon, S J; Kurtz, M J; Allende-Prieto, C; Beers, T C; Wilhelm, R; Brown, Warren R.; Geller, Margaret J.; Kenyon, Scott J.; Kurtz, Michael J.; Prieto, Carlos Allende; Beers, Timothy C.; Wilhelm, Ronald

    2005-01-01

    We discuss a 175 deg^2 spectroscopic survey for blue horizontal branch (BHB) stars in the Galactic halo. We use the Two Micron All Sky Survey (2MASS) and the Sloan Digital Sky Survey (SDSS) to select BHB candidates, and find that the 2MASS and SDSS color-selection is 38% and 50% efficient, respectively, for BHB stars. Our samples include one likely run-away B7 star 6 kpc below the Galactic plane. The global properties of the BHB samples are consistent with membership in the halo population: the median metallicity is [Fe/H]=-1.7, the velocity dispersion is 108 km/s, and the mean Galactic rotation of the BHB stars 3<|z|<15 kpc is -4 +- 30 km/s. We discuss the theoretical basis of the Preston, Shectman & Beers M_V-color relation for BHB stars, and conclude that intrinsic shape of the BHB M_V-color relation results from the physics of stars on the horizontal branch. We calculate the luminosity function for the field BHB star samples using the Efstathiou, Ellis, & Peterson maximum-likelihood method w...

  1. DNA Sampling Hook

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The DNA Sampling Hook is a significant improvement on a method of obtaining a tissue sample from a live fish in situ from an aquatic environment. A tissue sample...

  2. Bending of Light Near a Star and Gravitational Red/Blue Shift Alternative Explanation Based on Refraction of Light

    CERN Document Server

    Gupta, D R C

    2004-01-01

    Many of the general-relativity-tests such as bending of light near a star and gravitational red/blue shift are explained without general-relativity and without Newtonian-approach. The author first casts doubts on both, the Newtonian and the relativistic approach; and proposes a novel alternative-explanation. The new alternative-explanation is based on refraction-phenomenon of optics. It predicts that as the ray passes through/near the stars atmospheric-medium, it bends due to refraction-phenomenon towards star-core, like a ray bends while passing through a prism or water-drop. A semi-empirical estimation of the atmospheric-height and its refractive-index are made to find the refraction-results. The refraction-based theory also suggests new explanation for gravitational red/blue shift; it tells that frequency remains constant (as it is so in refraction-phenomenon) and the red/blue shift is due to change in wavelength due to change in velocity of light in the medium . Estimated results for bending of light and ...

  3. The Type IIn Supernova 2002kg: The Outburst of a Luminous Blue Variable Star in NGC 2403

    CERN Document Server

    Van Dyk, S D; Chornock, R; Filippenko, A V; Foley, R; Humphreys, R M; Li, W; Challis, Peter M.; Chornock, Ryan; Dyk, Schuyler D. Van; Filippenko, Alexei V.; Foley, Ryan; Humphreys, Roberta M.; Li, Weidong

    2006-01-01

    We show that Supernova (SN) 2002kg in NGC 2403, initially classified as Type II-narrow (IIn), has photometric and spectroscopic properties unlike those of normal SNe. Its behavior, instead, is more typical of highly massive stars which experience the short-lived luminous blue variable (LBV) phase toward the end of their lives. The star, in fact, most resembles the LBV S Doradus in outburst. The precursor of SN 2002kg is the irregular, bright blue variable star 37 (V37), catalogued by Tammann & Sandage in 1968. Using high-quality ground-based, multi-band images we can constrain the initial mass of V37 to be M_ini >~ 40 M_sun. We find that, although the spectra indicate a nitrogen enhancement, possibly revealing the products of CNO processing by V37 in the ejecta, the star lacks a substantial LBV nebula. The outburst from SN 2002kg/V37 is not nearly as energetic as the giant eruptions of the eta Carinae-like variables, such as SN 1954J/V12, also in NGC 2403. SN 2002kg/V37, however, is among a growing number...

  4. Blue straggler star populations in globular clusters - II. Proper-motion cleaned HST catalogues of BSSs in 38 Galactic GCs

    Science.gov (United States)

    Simunovic, Mirko; Puzia, Thomas H.

    2016-11-01

    We present new blue straggler star (BSS) catalogues in 38 Milky Way globular clusters (GCs) based on multipassband and multi-epoch treasury survey data from the Hubble Space Telescope. We measure precise astrometry and relative proper motions of stars in all target clusters and performed a subsequent cluster membership selection. We study the accuracy of our proper-motion measurements using estimates of central velocity dispersions and find very good agreement with previous studies in the literature. Finally, we present a homogeneous BSS selection method, that expands the classic BSS selection parameter space to more evolved BSS evolutionary stages. We apply this method to the proper-motion cleaned GC star catalogues in order to define proper-motion cleaned BSS catalogues in all 38 GCs, which we make publicly available to enable further study and follow-up observations.

  5. Blue Straggler Star Populations in Globular Clusters: II. Proper-Motion Cleaned HST Catalogs of BSSs in 38 Galactic GCs

    CERN Document Server

    Simunovic, Mirko

    2016-01-01

    We present new Blue Straggler Star (BSS) catalogs in 38 Milky Way globular clusters (GCs) based on multi-passband and multi-epoch treasury survey data from the Hubble Space Telescope. We measure precise astrometry and relative proper motions of stars in all target clusters and performed a subsequent cluster membership selection. We study the accuracy of our proper motion measurements using estimates of central velocity dispersions and find very good agreement with previous studies in the literature. Finally, we present a homogeneous BSS selection method, that expands the classic BSS selection parameter space to more evolved BSS evolutionary stages. We apply this method to the proper-motion cleaned GC star catalogs in order to define proper-motion cleaned BSS catalogs in all 38 GCs, which we make publicly available to enable further study and follow-up observations.

  6. The Rise and Fall of Star Formation Histories of Blue Galaxies at Redshifts 0.2 < z < 1.4

    Science.gov (United States)

    Pacifici, Camilla; Kassin, Susan A.; Weiner, Benjamin; Charlot, Stephane; Gardner, Jonathan P.

    2012-01-01

    Popular cosmological scenarios predict that galaxies form hierarchically from the merger of many progenitor, each with their own unique star formation history (SFH). We use the approach recently developed by Pacifici et al. to constrain the SFHs of 4517 blue (presumably star-forming) galaxies with spectroscopic redshifts in the range O.2 star formation and chemical enrichment histories, stellar population synthesis, nebular emission and attenuation by dust. We constrain the SFH of each galaxy in our sample by comparing the observed fluxes in the B, R,l and K(sub s) bands and rest-frame optical emission-line luminosities with those of one million model spectral energy distributions. We explore the dependence of the resulting SFH on galaxy stellar mass and redshift. We find that the average SFHs of high-mass galaxies rise and fall in a roughly symmetric bell-shaped manner, while those of low-mass galaxies rise progressively in time, consistent with the typically stronger activity of star formation in low-mass compared to high-mass galaxies. For galaxies of all masses, the star formation activity rises more rapidly at high than at low redshift. These findings imply that the standard approximation of exponentially declining SFHs wIdely used to interpret observed galaxy spectral energy distributions is not appropriate to constrain the physical parameters of star-forming galaxies at intermediate redshifts.

  7. Liquid-Crystalline Star-Shaped Supergelator Exhibiting Aggregation-Induced Blue Light Emission.

    Science.gov (United States)

    Pathak, Suraj Kumar; Pradhan, Balaram; Gupta, Monika; Pal, Santanu Kumar; Sudhakar, Achalkumar Ammathnadu

    2016-09-13

    A family of closely related star-shaped stilbene-based molecules containing an amide linkage are synthesized, and their self-assembly in liquid-crystalline and gel states was investigated. The number and position of the peripheral alkyl tails were systematically varied to understand the structure-property relation. Interestingly, one of the molecules with seven peripheral chains was bimesomorphic, exhibiting columnar hexagonal and columnar rectangular phases, whereas the rest of them stabilized the room-temperature columnar hexagonal phase. The self-assembly of these molecules in liquid-crystalline and organogel states is extremely sensitive to the position and number of alkoxy tails in the periphery. Two of the compounds with six and seven peripheral tails exhibited supergelation behavior in long-chain hydrocarbon solvents. One of these compounds with seven alkyl chains was investigated further, and it has shown higher stability and moldability in the gel state. The xerogel of the same compound was characterized with the help of extensive microscopic and X-ray diffraction studies. The nanofibers in the xerogel are found to consist of molecules arranged in a lamellar fashion. Furthermore, this compound shows very weak emission in solution but an aggregation-induced emission property in the gel state. Considering the dearth of solid-state blue-light-emitting organic materials, this molecular design is promising where the self-assembly and emission in the aggregated state can be preserved. The nonsymmetric design lowers the phase-transition temperatures.The presence of an amide bond helps to stabilize columnar packing over a long range because of its polarity and intermolecular hydrogen bonding in addition to promoting organogelation.

  8. Metallicity estimates for A-, F-, and G-type stars from the Edinburgh-Cape blue object survey

    CERN Document Server

    Beers, T C; O'Donoghue, D; Kilkenny, D; Stobie, R S; Koen, C; Wilhelm, R

    2000-01-01

    The Edinburgh-Cape Blue Object Survey is an ongoing project to identify and analyse a large sample of hot stars selected initially on the basis of photographic colours (down to a magnitude limit B~18.0) over the entire high-Galactic-latitude southern sky, then studied with broadband UBV photometry and medium-resolution spectroscopy. Due to unavoidable errors in the initial candidate selection, stars that are likely metal-deficient dwarfs and giants of the halo and thick-disk populations are inadvertently included, yet are of interest in their own right. In this paper we discuss a total of 206 candidate metal-deficient dwarfs, subgiants, giants, and horizontal-branch stars with photoelectric colours redder than (B-V)o = 0.3, and with available spectroscopy. Radial velocities, accurate to ~10-15 km/s, are presented for all of these stars. Spectroscopic metallicity estimates for these stars are obtained using a recently re-calibrated relation between Ca II K-line strength and (B-V)o colour. The identification of...

  9. The Frequency of Field Blue-Straggler Stars in the Thick Disk and Halo System of the Galaxy

    CERN Document Server

    Santucci, Rafael M; Rossi, Silvia; Beers, Timothy C; Reggiani, Henrique M; Lee, Young Sun; Xue, Xiang-Xiang; Carollo, Daniela

    2015-01-01

    We present an analysis of a new, large sample of field blue-straggler stars (BSSs) in the thick disk and halo system of the Galaxy, based on stellar spectra obtained during the Sloan Digital Sky Survey (SDSS) and the Sloan Extension for Galactic Understanding and Exploration (SEGUE). Using estimates of stellar atmospheric parameters obtained from application of the SEGUE Stellar Parameter Pipeline, we obtain a sample of some 8000 BSSs, which are considered along with a previously selected sample of some 4800 blue horizontal-branch (BHB) stars. We derive the ratio of BSSs to BHB stars, F$_{\\rm BSS/BHB}$, as a function of Galactocentric distance and distance from the Galactic plane. The maximum value found for F$_{\\rm BSS/BHB}$ is $\\sim~$4.0 in the thick disk (at 3 kpc $<$ $|$Z$|$ $<$ 4 kpc), declining to on the order of $\\sim~1.5-2.0$ in the inner-halo region; this ratio continues to decline to $\\sim~$1.0 in the outer-halo region. We associate a minority of field BSSs with a likely extragalactic origin; ...

  10. Blue Straggler Stars in Globular Clusters: a powerful tool to probe the internal dynamical evolution of stellar systems

    CERN Document Server

    Ferraro, Francesco R; Dalessandro, Emanuele; Mucciarelli, Alessio; Lovisi, Loredana

    2014-01-01

    This chapter presents an overview of the main observational results obtained to date about Blue Straggler Stars (BSSs) in Galactic Globular Clusters (GCs). The BSS specific frequency, radial distribution, chemical composition and rotational properties are presented and discussed in the framework of using this stellar population as probe of GC internal dynamics. In particular, the shape of the BSS radial distribution has been found to be a powerful tracer of the dynamical age of stellar systems, thus allowing the definition of the first empirical "dynamical clock".

  11. Mapping the Galactic Halo with blue horizontal branch stars from the 2dF quasar redshift survey

    CERN Document Server

    De Propris, Roberto; Mares, Peter J; CTIO,; University, Cornell

    2010-01-01

    We use 666 blue horizontal branch (BHB) stars from the 2Qz redshift survey to map the Galactic halo in four dimensions (position, distance and velocity). We find that the halo extends to at least 100 kpc in Galactocentric distance, and obeys a single power-law density profile of index ~-2.5 in two different directions separated by 150 degrees on the sky. This suggests that the halo is spherical. Our map shows no large kinematically coherent structures (streams, clouds or plumes) and appears homogeneous. However, we find that at least 20% of the stars in the halo reside in substructures and that these substructures are dynamically young. The velocity dispersion profile of the halo appears to increase towards large radii while the stellar velocity distribution is non Gaussian beyond 60 kpc. We argue that the outer halo consists of a multitude of low luminosity overlapping tidal streams from recently accreted objects.

  12. The Nature of Faint Blue Stars in the PHL and Ton Catalogues based on Digital Sky Surveys

    CERN Document Server

    Andernach, H; W., W Copo Cordova; Santiago-Bautista, I del C

    2015-01-01

    We determined accurate positions for 3000 of the "faint blue stars" in the PHL (Palomar-Haro-Luyten) and Ton/TonS catalogues. These were published from 1957 to 1962, and, aimed at finding new white dwarfs, provide approximate positions for about 10750 blue stellar objects. Some of these "stars" had become known as quasars, a type of objects unheard-of before 1963. We derived subarcsec positions from a comparison of published finding charts with images from the first-epoch Digitized Sky Survey. Numerous objects are now well known, but unfortunately neither their PHL or Ton numbers, nor their discoverers, are recognized in current databases. A comparison with modern radio, IR, UV and X-ray surveys leads us to suggest that the fraction of extragalactic objects in the PHL and Ton catalogues is at least 15 per cent. However, because we failed to locate the original PHL plates or finding charts, it may be impossible to correctly identify the remaining 7726 PHL objects.

  13. Two bi-stability jumps in theoretical wind models for massive stars and the implications for Luminous Blue Variable supernovae

    CERN Document Server

    Petrov, Blagovest; Gräfener, Götz

    2016-01-01

    Luminous Blue Variables have been suggested to be the direct progenitors of supernova types IIb and IIn, with enhanced mass loss prior to explosion. However, the mechanism of this mass loss is not yet known. Here, we investigate the qualitative behaviour of theoretical stellar wind mass-loss as a function of Teff across two bi-stability jumps in blue supergiant regime and also in proximity to the Eddington limit, relevant for LBVs. To investigate the physical ingredients that play a role in the radiative acceleration we calculate blue supergiant wind models with the CMFGEN non-LTE model atmosphere code over an effective temperature range between 30000 and 8800 K. Although our aim is not to provide new mass-loss rates for BA supergiants, we study and confirm the existence of two bi-stability jumps in mass-loss rates predicted by Vink, de Koter, & Lamers (1999). However, they are found to occur at somewhat lower Teff (20000 and 9000 K, respectively) than found previously, which would imply that stars may ev...

  14. A Spectroscopic Study of Blue Supergiant Stars in the Sculptor Galaxy NGC 55: Chemical Evolution and Distance

    Science.gov (United States)

    Kudritzki, R. P.; Castro, N.; Urbaneja, M. A.; Ho, I.-T.; Bresolin, F.; Gieren, W.; Pietrzyński, G.; Przybilla, N.

    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 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.

  15. Herschel imaging and spectroscopy of the nebula around the luminous blue variable star WRAY 15-751

    CERN Document Server

    Vamvatira-Nakou, C; Royer, P; Naze, Y; Magain, P; Exter, K; Waelkens, C; Groenewegen, M A T

    2013-01-01

    We have obtained far-infrared Herschel PACS imaging and spectroscopic observations of the nebular environment of the luminous blue variable WRAY 15-751. These images clearly show that the main, dusty nebula is a shell of radius 0.5 pc and width 0.35 pc extending outside the H-alpha nebula. They also reveal a second, bigger and fainter dust nebula, observed for the first time. Both nebulae lie in an empty cavity, likely the remnant of the O-star wind bubble formed when the star was on the main sequence. The kinematic ages of the nebulae are about 20000 and 80000 years and each nebula contains about 0.05 Msun of dust. Modeling of the inner nebula indicates a Fe-rich dust. The far-infrared spectrum of the main nebula revealed forbidden emission lines coming from ionized and neutral gas. Our study shows that the main nebula consists of a shell of ionized gas surrounded by a thin photodissociation region illuminated by an "average" early-B star. The derived abundance ratios N/O=1.0+/-0.4 and C/O=0.4+/-0.2 indicate...

  16. Clathrin-Mediated Auxin Efflux and Maxima Regulate Hypocotyl Hook Formation and Light-Stimulated Hook Opening in Arabidopsis.

    Science.gov (United States)

    Yu, Qinqin; Zhang, Ying; Wang, Juan; Yan, Xu; Wang, Chao; Xu, Jian; Pan, Jianwei

    2016-01-01

    The establishment of auxin maxima by PIN-FORMED 3 (PIN3)- and AUXIN RESISTANT 1/LIKE AUX1 (LAX) 3 (AUX1/LAX3)-mediated auxin transport is essential for hook formation in Arabidopsis hypocotyls. Until now, however, the underlying regulatory mechanism has remained poorly understood. Here, we show that loss of function of clathrin light chain CLC2 and CLC3 genes enhanced auxin maxima and thereby hook curvature, alleviated the inhibitory effect of auxin overproduction on auxin maxima and hook curvature, and delayed blue light-stimulated auxin maxima reduction and hook opening. Moreover, pharmacological experiments revealed that auxin maxima formation and hook curvature in clc2 clc3 were sensitive to auxin efflux inhibitors 1-naphthylphthalamic acid and 2,3,5-triiodobenzoic acid but not to the auxin influx inhibitor 1-naphthoxyacetic acid. Live-cell imaging analysis further uncovered that loss of CLC2 and CLC3 function impaired PIN3 endocytosis and promoted its lateralization in the cortical cells but did not affect AUX1 localization. Taken together, these results suggest that clathrin regulates auxin maxima and thereby hook formation through modulating PIN3 localization and auxin efflux, providing a novel mechanism that integrates developmental signals and environmental cues to regulate plant skotomorphogenesis and photomorphogenesis.

  17. Herschel imaging and spectroscopy of the nebula around the luminous blue variable star WRAY 15-751

    Science.gov (United States)

    Vamvatira-Nakou, C.; Hutsemékers, D.; Royer, P.; Nazé, Y.; Magain, P.; Exter, K.; Waelkens, C.; Groenewegen, M. A. T.

    2013-09-01

    We have obtained far-infrared Herschel-PACS imaging and spectroscopic observations of the nebular environment of the luminous blue variable (LBV) WRAY 15-751. The far-infrared images clearly show that the main, dusty nebula is a shell of radius 0.5 pc and width 0.35 pc extending outside the Hα nebula. Furthermore, these images reveal a second, bigger and fainter dust nebula that is observed for the first time. Both nebulae lie in an empty cavity, very likely the remnant of the O-star wind bubble formed when the star was on the main sequence. The kinematic ages of the nebulae are calculated to be about 2 × 104 and 8 × 104 years, and we estimated that each nebula contains ~0.05 M⊙ of dust. Modeling of the inner nebula indicates a Fe-rich dust. The far-infrared spectrum of the main nebula revealed forbidden emission lines coming from ionized and neutral gas. Our study shows that the main nebula consists of a shell of ionized gas surrounded by a thin photodissociation region illuminated by an "average" early-B star. We derive the abundance ratios N/O = 1.0 ± 0.4 and C/O = 0.4 ± 0.2, which indicate a mild N/O enrichment. From both the ionized and neutral gas components we estimate that the inner shell contains 1.7 ± 0.6 M⊙ of gas. Assuming a similar dust-to-gas ratio for the outer nebula, the total mass ejected by WRAY 15-751 amounts to 4 ± 2 M⊙. The measured abundances, masses and kinematic ages of the nebulae were used to constrain the evolution of the star and the epoch at which the nebulae were ejected. Our results point to an ejection of the nebulae during the red super-giant (RSG) evolutionary phase of an ~40 M⊙ star. The multiple shells around the star suggest that the mass-loss was not a continuous ejection but rather a series of episodes of extreme mass-loss. Our measurements are compatible with the recent evolutionary tracks computed for an ~40 M⊙ star with little rotation. They support the O-BSG-RSG-YSG-LBV filiation and the idea that high

  18. Blue Horizontal-Branch Stars The "Jump" in Strömgren u, Low Gravities, and Radiative Levitation of Metals

    CERN Document Server

    Grundahl, F; Landsman, W B; Stetson, P B; Andersen, M I

    1999-01-01

    We study the ``jump'' in the blue horizontal--branch (BHB) distribution first detected by Grundahl et al. (1998) in the Galactic globular cluster (GC) M13. On the basis of Stromgren photometry for a sample of fourteen GC's we show that: 1) The jump is best characterized as a systematic shift, on a (u, u-y) color-magnitude diagram, from canonical zero-age HB (ZAHB) models, in the sense that the stars appear brighter and/or hotter than the models; 2) the jump is a ubiquitous phenomenon, ocurring over the temperature range 11,500 < Teff < 20,000K; 3) An analogous feature is present in (log g, log Teff) diagrams -- indicating a common physical origin for the two phenomena; 4) The physical mechanism responsible for the jump phenomenon is most likely radiative levitation of iron and other

  19. Two bi-stability jumps in theoretical wind models for massive stars and the implications for luminous blue variable supernovae

    Science.gov (United States)

    Petrov, Blagovest; Vink, Jorick S.; Gräfener, Götz

    2016-05-01

    Luminous blue variables (LBVs) have been suggested to be the direct progenitors of supernova Types IIb and IIn, with enhanced mass loss prior to explosion. However, the mechanism of this mass loss is not yet known. Here, we investigate the qualitative behaviour of theoretical stellar wind mass loss as a function of Teff across two bi-stability jumps in blue supergiant regime and also in proximity to the Eddington limit, relevant for LBVs. To investigate the physical ingredients that play a role in the radiative acceleration we calculate blue supergiant wind models with the CMFGEN non-local thermodynamic equilibrium model atmosphere code over an effective temperature range between 30 000 and 8800 K. Although our aim is not to provide new mass-loss rates for BA supergiants, we study and confirm the existence of two bi-stability jumps in mass-loss rates predicted by Vink et al. However, they are found to occur at somewhat lower Teff (20 000 and 9000 K, respectively) than found previously, which would imply that stars may evolve towards lower Teff before strong mass loss is induced by the bi-stability jumps. When the combined effects of the second bi-stability jump and the proximity to Eddington limit are accounted for, we find a dramatic increase in the mass-loss rate by up to a factor of 30. Further investigation of both bi-stability jumps is expected to lead to a better understanding of discrepancies between empirical modelling and theoretical mass-loss rates reported in the literature, and to provide key inputs for the evolution of both normal AB supergiants and LBVs, as well as their subsequent supernova Type II explosions.

  20. Auto-consistent metallicity and star formation history of the nearest blue compact dwarf galaxy NGC 6789

    CERN Document Server

    García-Benito, Rubén

    2012-01-01

    We present a detailed auto-consistent study of the nearest blue compact dwarf galaxy NGC 6789 by means of optical and UV archive photometry data and optical long-slit ISIS-WHT spectroscopy observations of the five brightest star-forming knots. The analysis of the spectra in all knots allowed the derivation of ionic chemical abundances of oxygen, nitrogen, sulphur, argon and neon using measures of both the high- and low-excitation electron temperatures, leading to the conclusion that NGC 6789 is chemically homogeneous with low values of the abundance of oxygen in the range 12+log(O/H) = 7.80-7.93, but presenting at the same time higher values of the nitrogen-to-oxygen ratio than expected for its metal regime. We used archival HST/WFPC2 F555W and F814W observations of NGC 6789 to perform a photometric study of the colour-magnitude diagram (CMD) of the resolved stellar populations and derive its star formation history (SFH), which is compatible with the presence of different young and old stellar populations who...

  1. A spectroscopic study of blue supergiant stars in the Sculptor galaxy NGC 55: chemical evolution and distance

    CERN Document Server

    Kudritzki, Rolf; Castro, Norberto; Ho, I-Ting; Bresolin, Fabio; Gieren, Wolfgang; Pietrzynski, Grzegorz; Przybilla, Norbert

    2016-01-01

    Low resolution (4.5 to 5 Angstroem) 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 alpha-elements). A metallicity gradient of -0.22 +/- 0.06$ dex/R_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 stellar and interstellar medium gas mass column densities 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 extra-planar metal poor HII regions detected in previous work 1.13 to 2.22 kpc above th...

  2. The flux-weighted gravity-luminosity relationship of blue supergiant stars as a constraint for stellar evolution

    CERN Document Server

    Meynet, Georges; Georgy, Cyril

    2015-01-01

    (abridged) The flux-weighted gravity-luminosity relationship (FGLR) of blue supergiant stars (BSG) links their absolute magnitude to the spectroscopically determined flux-weighted gravity log g = Teff^4. BSG are the brightest stars in the universe at visual light and the application of the FGLR has become a powerful tool to determine extragalactic distances. Observationally, the FGLR is a tight relationship with only small scatter. It is, therefore, ideal to be used as a constraint for stellar evolution models. The goal of this work is to investigate whether stellar evolution can reproduce the observed FGLR and to develop an improved foundation of the FGLR as an extragalactic distance indicator. We use different grids of stellar models for initial masses between 9 and 40 Msun, for metallicities between Z = 0.002 and 0.014, with and without rotation, computed with various mass loss rates during the red supergiant phase. For each of these models we discuss the details of post-main sequence evolution and constru...

  3. MOST satellite photometry of stars in the M67 field: Eclipsing binaries, blue stragglers and delta-Scuti variables

    CERN Document Server

    Pribulla, Theodor; Matthews, Jaymie M; Kuschnig, Rainer; Rowe, Jason F; Guenther, David B; Moffat, Anthony F J; Sasselov, Dimitar; Walker, Gordon A H; Weiss, Werner W

    2008-01-01

    We present two series of MOST (Microvariability & Oscillations of STars) space-based photometry, covering nearly continuously 10 days in 2004 and 30 days in 2007, of selected variable stars in the upper Main Sequence of the old open cluster M67. New high-precision light curves were obtained for the blue-straggler binary/triple systems AH Cnc, ES Cnc and EV Cnc. The precision and phase coverage of ES Cnc and EV Cnc is by far superior to any previous observations. The light curve of ES Cnc is modelled in detail, assuming two dark photospheric spots and Roche geometry. An analysis of the light curve of AH Cnc indicates a low mass ratio (q about 0.13) and a high inclination angle for this system. Two new long-period eclipsing binaries, GSC 814-323 and HD75638 (non-members of M67) were discovered. We also present ground-based DDO spectroscopy of ES Cnc and of the newly found eclipsing binaries. Especially interesting is HD75638, a member of a visual binary, which must itself be a triple or a higher-multiplicit...

  4. Continuum and line emission of flares on red dwarf stars: origin of the blue continuum radiation

    CERN Document Server

    Morchenko, E S

    2016-01-01

    There are two types of models that explain the appearance of the blue continuum radiation during the impulsive phase of stellar flares. Grinin and Sobolev (Astrophysics, vol. 13, 348, 1977) argue that this component of the optical continuum is formed in "the transition layer between the chromosphere and the photosphere". Katsova et al. (Astrophysics, vol. 17, 156, 1981) have "raised" the source of the white-light continuum up to the dense region in the perturbed chromosphere. In the present contribution (the main paper was submitted to journal "Astrophysics"), we show that the statement by Katsova et al. is erroneous.

  5. Radio detection of nebulae around four luminous blue variable stars in the Large Magellanic Cloud

    OpenAIRE

    Agliozzo, C.; Umana, G.; Trigilio, C.; Buemi, C; Leto, P.; Ingallinera, A.; T. Franzen; Noriega-Crespo, A.

    2012-01-01

    The nebulae associated with four luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC) have been observed at 5.5 and 9 GHz using the Australia Telescope Compact Array, and radio emission has been detected for first time in sources R127, R143, S61 and S119. The radio maps of the nebulae have an angular resolution of ∼1.5 arcsec and a sensitivity of 1.5–3.0 × 10^(−2)  mJy  beam^(−1) and show a very similar morphology to that observed in Hα. This similarity permits us to assume that...

  6. MOCCA code for star cluster simulations - VI. Bimodal spatial distribution of blue stragglers

    CERN Document Server

    Hypki, Arkadiusz

    2016-01-01

    The paper presents an analysis of formation mechanism and properties of spatial distributions of blue stragglers in evolving globular clusters, based on numerical simulations done with the MOCCA code. First, there are presented N-body and MOCCA simulations which try to reproduce the simulations presented by Ferraro (2012). Then, the agreement between N-body and the MOCCA code is shown. Finally, we discuss the formation process of the bimodal distribution. We report that so-called bimodal spatial distribution of blue stragglers is a very transient feature. It is formed for one snapshot in time and it can easily vanish in the next one. Moreover, we show that the radius of avoidance proposed by Ferraro (2012) goes out of sync with the apparent minimum of the bimodal distribution after about two half-mass relaxation times. This finding creates a real challenge for the dynamical clock, which uses this radius to determine the dynamical age of globular clusters. Additionally, the paper discusses a few important prob...

  7. Deep multiband surface photometry on star forming galaxies: I. A sample of 24 blue compact galaxies

    CERN Document Server

    Micheva, Genoveva; Bergvall, Nils; Zackrisson, Erik; Masegosa, Josefa; Marquez, Isabel; Marquart, Thomas; Durret, Florence

    2012-01-01

    [Abridged] We present deep optical and near-infrared UBVRIHKs imaging data for 24 blue compact galaxies (BCGs). The sample contains luminous dwarf and intermediate-mass BCGs which are predominantly metal-poor, although a few have near-solar metallicities. We have analyzed isophotal and elliptical integration surface brightness and color profiles, extremely deep (mu_B<29 mag arcsec^{-2}) contour maps and RGB images for each galaxy in the sample. The colors are compared to different spectral evolutionary models. We detect extremely extended low surface brightness (LSB) components dominant beyond the Holmberg radius as well as optical bridges between companion galaxies at the mu_V~28th mag arcsec^{-2} isophotal level. The central surface brightness mu_0 and scale length h_r are derived from two radial ranges typically assumed to be dominated by the underlying host galaxy. We find that mu_0 and h_r of the BCGs host deviate from those of dwarf ellipticals (dE) and dwarf irregulars (dI) solely due to a strong bu...

  8. The Hottest Horizontal-Branch Stars in Omega Centauri: Late Hot Flasher vs. Helium Enrichment

    Science.gov (United States)

    Moehler, S.; Dreizler, S.; Lanz, T.; Bono, G.; Sweigart, A V.; Calamida, A.; Monelli, M.; Nonino, M.

    2007-01-01

    UV observations of some massive globular clusters uncovered a significant population of very hot stars below the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either by the late hot flasher scenario here stars experience the helium flash while on the white dwarf cooling curve or by the helium-rich sub-population recently postulated to exist in some clusters. Spectroscopic analyses of blue hook stars in omega Cen and NGC 2808 support the late hot flasher scenario, but the stars contain much less helium than expected and the predicted C, N enrichment could not be verified from existing data. We want to determine effective temperatures, surface gravities and abundances of He, C, N in blue hook and canonical extreme horizontal branch (EHB) star candidates. Moderately high resolution spectra of stars at the hot end of the blue horizontal branch in the globular cluster omega Cen were analysed for atmospheric parameters (T(sub eff), log g) and abundances using LTE and Non-LTE model atmospheres. In the temperature range 30,000 K to 50,000 K we find that 37% of our stars are helium-poor (log nHe/nH less than -2), 49% have solar helium abundance within a factor of 3 (-1.5 less than or equal to log nHe/nH less than or equal to -0.5) and 14% are helium rich (log nHe/nH greater than -0.4). We also find carbon enrichment in step with helium enrichment, with a maximum carbon enrichment of 3% by mass. At least 30% of the hottest HB stars in omega Centauri show helium abundances well above the predictions from the helium enrichment scenario (Y = 0.42 corresponding to log nHe/nH approximately equal to -0.74). In addition the most helium-rich stars show strong carbon enrichment as predicted by the late hot flasher scenario. We conclude that the helium-rich HB stars in omega Cen cannot be explained solely by the helium-enrichment scenario invoked to explain the blue main sequence.

  9. KINEMATICS OF THE STELLAR HALO AND THE MASS DISTRIBUTION OF THE MILKY WAY USING BLUE HORIZONTAL BRANCH STARS

    International Nuclear Information System (INIS)

    Here, we present a kinematic study of the Galactic halo out to a radius of ∼60 kpc, using 4664 blue horizontal branch stars selected from the SDSS/SEGUE survey to determine key dynamical properties. Using a maximum likelihood analysis, we determine the velocity dispersion profiles in spherical coordinates (σr, σθ, σφ) and the anisotropy profile (β). The radial velocity dispersion profile (σr) is measured out to a galactocentric radius of r ∼ 60 kpc, but due to the lack of proper-motion information, σθ, σφ, and β could only be derived directly out to r ∼ 25 kpc. From a starting value of β ≈ 0.5 in the inner parts (9 circ) of the Galaxy out to r ∼ 25 kpc. The mass of the Galaxy within r ∼11 M☉, and with a three-component fit to vcirc(r), we determine the virial mass of the Milky Way dark matter halo to be Mvir = 0.9+0.4–0.3 × 1012 M☉ (Rvir = 249+34–31 kpc).

  10. The Century Survey Galactic Halo Project III: A Complete 4300 deg^2 Survey of Blue Horizontal Branch Stars in the Metal-Weak Thick Disk and Inner Halo

    CERN Document Server

    Brown, Warren R; Wilhelm, Ronald; Prieto, Carlos Allende; Geller, Margaret J; Kenyon, Scott J; Kurtz, Michael J

    2007-01-01

    We present a complete spectroscopic survey of 2414 2MASS-selected blue horizontal branch (BHB) candidates selected over 4300 deg^2 of the sky. We identify 655 BHB stars in this non-kinematically selected sample. We calculate the luminosity function of field BHB stars and find evidence for very few hot BHB stars in the field. The BHB stars located at a distance from the Galactic plane |Z|<4 kpc trace what is clearly a metal-weak thick disk population, with a mean metallicity of [Fe/H]= -1.7, a rotation velocity gradient of dv_{rot}/d|Z|= -28+-3.4 km/s in the region |Z|<6 kpc, and a density scale height of h_Z= 1.26+-0.1 kpc. The BHB stars located at 5<|Z|<9 kpc are a predominantly inner-halo population, with a mean metallicity of [Fe/H]= -2.0 and a mean Galactic rotation of -4+-31 km/s. We infer the density of halo and thick disk BHB stars is 104+-37 kpc^-3 near the Sun, and the relative normalization of halo to thick-disk BHB stars is 4+-1% near the Sun.

  11. Blue and IR Light Curves of the Mysterious Pre-Main Sequence Star V582 Mon (KH 15D) from 1955 to 1970

    CERN Document Server

    Maffei, P; Tosti, G; Maffei, Paolo; Ciprini, Stefano; Tosti, Gino

    2004-01-01

    In recent years, an increasing number of publications have been addressed to the peculiar and mysterious pre-main sequence star V582 Mon, also known as KH 15D. This extraordinary T Tauri star, located in the young star cluster NGC 2264, appears as to be an eclipsing variable. In the present paper, we report a unique and self-consistent set of light curves in the blue and near-infrared bands, spanning a 15-year interval (epoch 1955-1970). Our photometric data show clearly the beginning of the eclipse stage occurred in early 1958 in the blue, and perhaps around four years later in the infrared. The light curve period turns out to be the same reported by recent observations (about 48.3 days), so that no evidence for a period change results. On the other hand, in our data the light curve shape appears as sinusoidal and is therefore different from the one displayed today. The photometric behaviour, determined with time-series and colour-index analysis, suggests that V582 Mon (KH 15D) could be initially surrounded ...

  12. Hooke, Robert (1635-1703)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    Scientist, born in Freshwater, Isle of Wight, England, educated at Christ Church College, Oxford where he met Boyle and was employed by him to construct his air pump, became professor of geometry at Gresham College, London. Discovered Hooke's law of elasticity. Worked on optics, simple harmonic motion and elasticity in strings. Published a monograph called Micrographia, containing beautiful pict...

  13. KINEMATICS OF THE STELLAR HALO AND THE MASS DISTRIBUTION OF THE MILKY WAY USING BLUE HORIZONTAL BRANCH STARS

    Energy Technology Data Exchange (ETDEWEB)

    Kafle, Prajwal R.; Sharma, Sanjib; Lewis, Geraint F.; Bland-Hawthorn, Joss, E-mail: p.kafle@physics.usyd.edu.au [Sydney Institute for Astronomy, School of Physics, A28, University of Sydney, NSW 2006 (Australia)

    2012-12-20

    Here, we present a kinematic study of the Galactic halo out to a radius of {approx}60 kpc, using 4664 blue horizontal branch stars selected from the SDSS/SEGUE survey to determine key dynamical properties. Using a maximum likelihood analysis, we determine the velocity dispersion profiles in spherical coordinates ({sigma}{sub r}, {sigma}{sub {theta}}, {sigma}{sub {phi}}) and the anisotropy profile ({beta}). The radial velocity dispersion profile ({sigma}{sub r}) is measured out to a galactocentric radius of r {approx} 60 kpc, but due to the lack of proper-motion information, {sigma}{sub {theta}}, {sigma}{sub {phi}}, and {beta} could only be derived directly out to r {approx} 25 kpc. From a starting value of {beta} Almost-Equal-To 0.5 in the inner parts (9 < r/kpc < 12), the profile falls sharply in the range r Almost-Equal-To 13-18 kpc, with a minimum value of {beta} = -1.2 at r = 17 kpc, rising sharply at larger radius. In the outer parts, in the range 25 < r/kpc < 56, we predict the profile to be roughly constant with a value of {beta} Almost-Equal-To 0.5. The newly discovered kinematic anomalies are shown not to arise from halo substructures. We also studied the anisotropy profile of simulated stellar halos formed purely by accretion and found that they cannot reproduce the sharp dip seen in the data. From the Jeans equation, we compute the stellar rotation curve (v{sub circ}) of the Galaxy out to r {approx} 25 kpc. The mass of the Galaxy within r {approx}< 25 kpc is determined to be 2.1 Multiplication-Sign 10{sup 11} M{sub Sun }, and with a three-component fit to v{sub circ}(r), we determine the virial mass of the Milky Way dark matter halo to be M{sub vir} = 0.9{sup +0.4}{sub -0.3} Multiplication-Sign 10{sup 12} M{sub Sun} (R{sub vir} = 249{sup +34}{sub -31} kpc).

  14. 2,4-Dicyano-3-diethylamino-9,9-diethylfluorene Based Blue Light-emitting Star-shaped Compounds: Synthesis and Properties

    Institute of Scientific and Technical Information of China (English)

    CHEN,Xiaohang; CHEN,Xiaopeng; ZHAO,Zujin; L(U),Ping; WANG,Yanguang

    2009-01-01

    Two new star-shaped molecules 1 and 2 containing a triphenylamine/benzene moiety as the central core and three 2,4-dicyano-3-diethylamino-9,9-diethylfluorene moieties as the peripheral functional groups were synthesized and characterized. Charge transfer properties for these compounds were observed in photophysical experiments due to their D-A molecular structure. Compound 1 presented dual fluorescence in high polar solvents. Moreover, these compounds exhibited moderate fluorescence and high thermal stabilities, indicating their potential application to blue light emitting materials.

  15. Statistical Properties of Blue Horizontal Branch Stars in the Spheroid: Detection of a Moving Group approximately 50 kpc from the Sun

    CERN Document Server

    Harrigan, Matthew J; Newberg, Lee A; Yanny, Brian; Beers, Timothy C; Lee, Young Sun; Fiorentin, Paola Re

    2010-01-01

    A new moving group comprising at least four Blue Horizontal Branch (BHB) stars is identified at (l,b) = (65 deg, 48 deg). The horizontal branch at g0=18.9 magnitude implies a distance of 50 kpc from the Sun. The heliocentric radial velocity is RV = -157 +/- 4 km/s, corresponding to V(gsr) = -10 km/s; the dispersion in line-of-sight velocity is consistent with the instrumental errors for these stars. The mean metallicity of the moving group is [Fe/H] approximately -2.4, which is significantly more metal poor than the stellar spheroid. We estimate that the BHB stars in the outer halo have a mean metallicity of [Fe/H] = -2.0, with a wide scatter and a distribution that does not change much as a function of distance from the Sun. We explore the systematics of SDSS DR7 surface gravity metallicity determinations for faint BHB stars, and present a technique for estimating the significance of clumps discovered in multidimensional data. This moving group cannot be distinguished in density, and highlights the need to c...

  16. SN 2015bh: NGC 2770's 4th supernova or a luminous blue variable on its way to a Wolf-Rayet star?

    CERN Document Server

    Thöne, C C; Leloudas, G; Gall, C; Cano, Z; Maeda, K; Schulze, S; Campana, S; Wiersema, K; Groh, J; de la Rosa, J; Bauer, F E; Malesani, D; Maund, J; Morrell, N; Beletsky, Y

    2016-01-01

    Very massive stars in the final phases of their lives often show unpredictable outbursts that can mimic supernovae, so-called, "SN impostors", but the distinction is not always straigthforward. Here we present observations of a luminous blue variable (LBV) in NGC 2770 in outburst over more than 20 years that experienced a possible terminal explosion as type IIn SN in 2015, named SN 2015bh. This possible SN or "main event" was preceded by a precursor peaking $\\sim$ 40 days before maximum. The total energy release of the main event is $\\sim$1.8$\\times$10$^{49}$ erg, which can be modeled by a $<$ 0.5 M$_\\odot$ shell plunging into a dense CSM. All emission lines show a single narrow P-Cygni profile during the LBV phase and a double P-Cygni profile post maximum suggesting an association of this second component with the possible SN. Since 1994 the star has been redder than during a typical S-Dor like outburst. SN 2015bh lies within a spiral arm of NGC 2770 next to a number of small star-forming regions with a m...

  17. Hubble Space Telescope proper motion (HSTPROMO) catalogs of Galactic globular clusters. IV. Kinematic profiles and average masses of blue straggler stars

    CERN Document Server

    Baldwin, A T; van der Marel, R P; Bianchini, P; Bellini, A; Anderson, J

    2016-01-01

    We make use of the Hubble Space Telescope proper-motion catalogs derived by Bellini et al. (2014) to produce the first radial velocity-dispersion profiles sigma(R) for blue straggler stars (BSSs) in Galactic globular clusters (GCs), as well as the first dynamical estimates for the average mass of the entire BSS population. We show that BSSs typically have lower velocity dispersions than stars with mass equal to the main-sequence turnoff mass, as one would expect for a more massive population of stars. Since GCs are expected to experience some degree of energy equipartition, we use the relation sigma~M^-eta, where eta is related to the degree of energy equipartition, along with our velocity-dispersion profiles to estimate BSS masses. We estimate eta as a function of cluster relaxation from recent Monte Carlo cluster simulations by Bianchini et al. (2016b) and then derive an average mass ratio M_BSS /M_MSTO=1.50+/-0.14 and an average mass M_BSS=1.22+/-0.12 M_Sun from 598 BSSs across 19 GCs. The final error bars...

  18. Stellar envelope inflation near the Eddington limit. Implications for the radii of Wolf-Rayet stars and luminous blue variables

    CERN Document Server

    Gräfener, G; Vink, J S

    2011-01-01

    (shortened) It has been proposed that the envelopes of luminous stars may be subject to substantial radius inflation. The inflation effect has been discussed in relation to the radius problem of WR stars, but has yet failed to explain the large observed radii of Galactic WR stars. We wish to obtain a physical perspective of the inflation effect, and study the consequences for the radii of WR stars, and LBVs. For WR stars the observed radii are up to an order of magnitude larger than predicted by theory, whilst S Doradus-type LBVs are subject to humongous radius variations, which remain as yet ill-explained. We use a dual approach to investigate the envelope inflation, based on numerical models for stars near the Eddington limit, and a new analytic formalism to describe the effect. An additional new aspect is that we take the effect of density inhomogeneities (clumping) within the outer stellar envelopes into account. Due to the effect of clumping we are able to bring the observed WR radii in agreement with th...

  19. Selectivity of hook type on hooking species for the tuna longline fishery in the Southern and Central Indian Ocean%印度洋中南部水域金枪鱼延绳钓钓钩钩型对钓获对象的选择性

    Institute of Scientific and Technical Information of China (English)

    朱国平; 陈锦淘; 许柳雄; 李攀

    2011-01-01

    Based on the data collected from the fishing ground of tuna longliners in the Southern-central Indian Ocean during September 2008 to April 2009, the present study compares and analyzes the catchability and selectivity to hooking species for 3 hook types(traditional tuna hook, "J"-type hook and circle hook).The results show that (1) for traditional tuna hook, the proportion of bigeye tuna( Thunnus obesus, BET)and blue shark( Prionace glauca,BLS)is higher than other species in the catch composition and "J"-type hook and circle hook have a similar hooking proportion for the above two species, however, for albacore ( Thunnus alalunga, ALB), the traditional tuna hook has the highest hooking proportion and followed by "J"-type hook and circle hook.(2) the traditional tuna hook has the highest survival rate and the "J"-type is lowest for BET, the survival rate of "J"-type hook is slightly higher than that of circle hook and the traditional tuna hook is the lowest for ALB, the survival rate of circle hook is highest and followed by traditional tuna hook and "J"-type hook for BLS.(3) the average fork length(FL) of ALB for "J"-type hook is slightly larger than that of traditional tuna hook and circle hook, traditional tuna hook is larger than circle hook and "J"-type hook for BET and "J"-type is larger than circle hook and traditional tuna hook for BLS.(4) significant difference has not been found for the FL distribution of ALB, BET and BLS for 3 hook types.%基于2008年9月至2009年4月在印度洋中南部水域金枪鱼延绳钓渔场收集的数据,研究分析和比较了3种钓钩钩型(传统金枪鱼钩、"J"形钩和圆形钩)的渔获效益及对钓捕对象的选择性.结果表明:(1)从渔获种类上看,大眼金枪鱼和大青鲨金枪鱼钩钓获比例最高,"J"形钩和圆形钩的钓获比例相当;而长鳍金枪鱼则为金枪鱼钩钓获比例最高,其次为"J"形钩和圆形钩.(2)大眼金枪鱼存活率以金枪鱼钩最高,"J"形钩最低;长鳍

  20. The Galactic O-Star Spectroscopic Survey. I. Classification System and Bright Northern Stars in the Blue-Violet at R~2500

    CERN Document Server

    Sota, A; Walborn, N R; Alfaro, E J; Barbá, R H; Morrell, N I; Gamen, R C; Arias, J I

    2011-01-01

    We present the first installment of a massive spectroscopic survey of Galactic O stars, based on new, high signal-to-noise ratio, R~2500 digital observations from both hemispheres selected from the Galactic O-Star Catalog of Ma\\'iz Apell\\'aniz et al. (2004) and Sota et al. (2008). The spectral classification system is rediscussed and a new atlas is presented, which supersedes previous versions. Extensive sequences of exceptional objects are given, including types Ofc, ON/OC, Onfp, Of?p, Oe, and double-lined spectroscopic binaries. The remaining normal spectra bring this first sample to 184 stars, which is close to complete to B=8 and north of delta = -20 and includes all of the northern objects in Ma\\'iz Apell\\'aniz et al. (2004) that are still classified as O stars. The systematic and random accuracies of these classifications are substantially higher than previously attainable, because of the quality, quantity, and homogeneity of the data and analysis procedures. These results will enhance subsequent invest...

  1. Engineering the Interconnecting Position of Star-Shaped Donor-π-Acceptor Molecules Based on Triazine, Spirofluorene, and Triphenylamine Moieties for Color Tuning from Deep Blue to Green.

    Science.gov (United States)

    Wang, Yafei; Liu, Wanhui; Deng, Jiyong; Xie, Guohua; Liao, Yuanwei; Qu, Zuoming; Tan, Hua; Liu, Yu; Zhu, Weiguo

    2016-09-20

    Pi-conjugated organic molecules featuring the donor-bridge-acceptor (D-π-A) structure have been widely used in semiconducting materials owing to their rigid structure, good thermal stability, excellent charge transfer, and high emission efficiency. To investigate the effect of the D-π-A molecular structure on the photophysical properties, in this contribution, three star-shaped D-π-A isomers based on the 2,4,6-triphenyl-1,3,5-triazine, spirofluorene, and triphenylamine moieties, that is, p-TFTPA, mp-TFTPA, and m-TFTPA, were synthesized by elaborately engineering the interconnecting position in the building-block units. The optophysical properties of these compounds were systematically explored by experiments and theory calculations. Definitively, changing the interconnecting position in these molecules played a significant role in the degree of π conjugation, which resulted in tunable emission colors from deep blue to green. Moreover, these isomers were employed as emissive dopants in organic light-emitting diodes. The highest external quantum efficiency of 2.3 % and current efficiency of 6.2 cd A(-1) were achieved by using the p-TFTPA based device. This research demonstrates a feasible way to realize blue emitters by engineering D-π-A conjugation.

  2. Designing physics video hooks for science students

    Science.gov (United States)

    McHugh, M.; McCauley, V.

    2016-01-01

    This paper offers an insight into the design structure of physics video hooks that were developed by the Science Education Resource design team in the school of education (SOE) in National University of Ireland, Galway (NUI Galway). A hook, is an instructional technique used to stimulate student attention (Hunter 1994, Lemov 2010), interest (Jewett 2013) and engagement (McCrory 2011, Riendeau 2013). The physics video hooks followed a design framework that is illustrated below by breaking down the centre of gravity (COG) hook. Various design principles and elements embedded within the COG hook are presented with examples and the time they occur within the video. The intention of this article is that the design can be replicated and modified to aid teachers and designers in the development of a multitude of classroom based multimedia resources.

  3. Hubble Space Telescope Proper Motion (HSTPROMO) Catalogs of Galactic Globular Clusters. IV. Kinematic Profiles and Average Masses of Blue Straggler Stars

    Science.gov (United States)

    Baldwin, A. T.; Watkins, L. L.; van der Marel, R. P.; Bianchini, P.; Bellini, A.; Anderson, J.

    2016-08-01

    We make use of the Hubble Space Telescope proper-motion catalogs derived by Bellini et al. to produce the first radial velocity dispersion profiles σ (R) for blue straggler stars (BSSs) in Galactic globular clusters (GCs), as well as the first dynamical estimates for the average mass of the entire BSS population. We show that BSSs typically have lower velocity dispersions than stars with mass equal to the main-sequence turnoff mass, as one would expect for a more massive population of stars. Since GCs are expected to experience some degree of energy equipartition, we use the relation σ \\propto {M}-η , where η is related to the degree of energy equipartition, along with our velocity dispersion profiles to estimate BSS masses. We estimate η as a function of cluster relaxation from recent Monte Carlo cluster simulations by Bianchini et al. and then derive an average mass ratio {M}{BSS}/{M}{MSTO}=1.50+/- 0.14 and an average mass {M}{BSS}=1.22+/- 0.12 M ⊙ from 598 BSSs across 19 GCs. The final error bars include any systematic errors that are random between different clusters, but not any potential biases inherent to our methodology. Our results are in good agreement with the average mass of {M}{BSS}=1.22+/- 0.06 M ⊙ for the 35 BSSs in Galactic GCs in the literature with properties that have allowed individual mass determination. Based on proprietary and archival observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.

  4. When stars collide

    NARCIS (Netherlands)

    Glebbeek, E.; Pols, O.R.

    2007-01-01

    When two stars collide and merge they form a new star that can stand out against the background population in a star cluster as a blue straggler. In so called collision runaways many stars can merge and may form a very massive star that eventually forms an intermediate mass blackhole. We have perfor

  5. ANALYSIS OF TOWING HOOKS OF CARS

    Directory of Open Access Journals (Sweden)

    K. Turgut YÜKSEL

    2005-02-01

    Full Text Available Towing hooks generally are assembled to vehicles as accessory. They are used to tow caravans and trailers having no engine, which provide accommodation and haulage of loads, respectively. So, the transport capacity of cars is increased safely. Towing hooks require different constructive structures due to different chassis or monocoque body of each car type; hence they are to be manufactured and assembled in small- or middle-size factories as per order. In this study, three different constructions of towing hook are modelled and structurally analysed. The results obtained are compared with each other to improve the structural strength.

  6. Homage to Robert Hooke (1635-1703): new insights from the recently discovered Hooke Folio.

    Science.gov (United States)

    Gest, Howard

    2009-01-01

    Microorganisms were first observed by Robert Hooke and Antoni van Leeuwenhoek between 1665 and 1678. In 1665, Hooke published Micrographia, which depicted the details of 60 objects as seen in the microscope. One chapter was devoted to the microfungus Mucor, the first microbe observed by the human eye. Leeuwenhoek, despite having no scientific training, became the first to observe protozoa, red blood cells, the sperm cells of animals, and bacteria, which he described in numerous letters to the Royal Society of London. In 1677, Hooke became Secretary of the Royal Society and, in the same year, confirmed some of Leeuwenhoek's discoveries. The discovery in 2006 of more than 650 pages of Hooke's missing records (the "Hooke Folio") allows us to verify the proceedings of Royal Society meetings and promises to be an important new source of Hooke's views on the renaissance of science in the 17th century. PMID:19684374

  7. Red or blue? A potential kilonova imprint of the delay until black hole formation following a neutron star merger

    CERN Document Server

    Metzger, Brian D

    2014-01-01

    Mergers of binary neutron stars (NSs) usually result in the formation of a hypermassive neutron star (HMNS). Whether- and when this remnant collapses to a black hole (BH) depends primarily on the equation of state and on angular momentum transport processes, both of which are uncertain. Here we show that the lifetime of the merger remnant may be directly imprinted in the radioactively powered kilonova emission following the merger. We employ axisymmetric, time-dependent hydrodynamic simulations of remnant accretion disks orbiting a HMNS of variable lifetime, and characterize the effect of this delay to BH formation on the disk wind ejecta. Our models follow the system evolution over several seconds, and include the effect of nuclear recombination, viscous heating, and neutrino irradiation by both the HMNS and the disk. When BH formation is relatively prompt ( 140, resulting in ~week-long emission with a spectral peak in the near-infrared (NIR), similar to that produced by the dynamical ejecta. In contrast, de...

  8. AKNA: Another AT-hook transcription factor"hooking-up"with inflammation

    Institute of Scientific and Technical Information of China (English)

    Alison R Moliterno; Linda MS Resar

    2011-01-01

    Previous studies highlight a key role for AT-hook transcription factors as master regulators of fundamental cellular processes involved in development,immune function,cancer,diabetes and other human diseases [1,2].The high mobility group A (HMGA) proteins are an important family of AT-hook chromatin remodeling proteins that orchestrate transcriptional complexes to regulate gene expression [ 1 ].Recent studies have uncovered links between HMG AT-hook transcription factors and inflammation [1-8].

  9. EAARL Coastal Topography-Sandy Hook 2007

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A first surface/bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the Gateway National Recreation Area's Sandy Hook Unit in New Jersey...

  10. cry1 and GPA1 signaling genetically interact in hook opening and anthocyanin synthesis in Arabidopsis

    OpenAIRE

    Fox, Ana R.; Soto, Gabriela C.; Jones, Alan M.; Casal, Jorge J.; Muschietti, Jorge P.; Mazzella, María A

    2012-01-01

    While studying blue light-independent effects of cryptochrome 1 (cry1) photoreceptor, we observed premature opening of the hook in cry1 mutants grown in complete darkness, a phenotype that resembles the one described for the heterotrimeric G-protein α subunit (GPA1) null mutant gpa1. Both cry1 and gpa1 also showed reduced accumulation of anthocyanin under blue light. These convergent gpa1 and cry1 phenotypes required the presence of sucrose in the growth media and were not additive in the cry...

  11. Bona-fide, strong-variable galactic Luminous Blue Variable stars are fast rotators: detection of a high rotational velocity in HR Carinae

    CERN Document Server

    Groh, Jose H; Hillier, D John; Barba, Rodolfo; Fernandez-Lajus, Eduardo; Gamen, Roberto C; Moises, Alessandro; Solivella, Gladys; Teodoro, Mairan

    2009-01-01

    We report optical observations of the Luminous Blue Variable (LBV) HR Carinae which show that the star has reached a visual minimum phase in 2009. More importantly, we detected absorptions due to Si IV 4088-4116 Angstroms. To match their observed line profiles from 2009 May, a high rotational velocity of vrot=150 +- 20 km/s is needed (assuming an inclination angle of 30 degrees), implying that HR Car rotates at ~0.88 +- 0.2 of its critical velocity for break-up (vcrit). Our results suggest that fast rotation is typical in all strong-variable, bona-fide galactic LBVs, which present S Dor-type variability. Strong-variable LBVs are located in a well-defined region of the HR diagram during visual minimum (the "LBV minimum instability strip"). We suggest this region corresponds to where vcrit is reached. To the left of this strip, a forbidden zone with vrot/vcrit>1 is present, explaining why no LBVs are detected in this zone. Since dormant/ex LBVs like P Cygni and HD 168625 have low vrot, we propose that LBVs can ...

  12. Postpartum Blues

    Medline Plus

    Full Text Available ... blues The postpartum blues E-mail to a friend Please fill in all fields. Please enter a ... blues: Talk to your partner or a good friend about how you feel Get plenty of rest ...

  13. EAARL Coastal Topography - Sandy Hook 2007

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Stevens, Sara; Yates, Xan; Bonisteel, Jamie M.

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Northeast Coastal and Barrier Network, Kingston, RI; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of Gateway National Recreation Area's Sandy Hook Unit in New Jersey, acquired on May 16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL) was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then

  14. Oscillating Rim Hook Tableaux and Colored Matchings

    CERN Document Server

    Chen, William Y C

    2011-01-01

    Motivated by the question of finding a type B analogue of the bijection between oscillating tableaux and matchings, we find a correspondence between oscillating m-rim hook tableaux and m-colored matchings, where m is a positive integer. An oscillating m-rim hook tableau is defined as a sequence $(\\lambda^0,\\lambda^1,...,\\lambda^{2n})$ of Young diagrams starting with the empty shape and ending with the empty shape such that $\\lambda^{i}$ is obtained from $\\lambda^{i-1}$ by adding an m-rim hook or by deleting an m-rim hook. Our bijection relies on the generalized Schensted algorithm due to White. An oscillating 2-rim hook tableau is also called an oscillating domino tableau. When we restrict our attention to two column oscillating domino tableaux of length 2n, we are led to a bijection between such tableaux and noncrossing 2-colored matchings on $\\{1, 2,..., 2n\\}$, which are counted by the product $C_nC_{n+1}$ of two consecutive Catalan numbers. A 2-colored matching is noncrossing if there are no two arcs of th...

  15. Hooking Up and Identity Development of Female College Students

    Science.gov (United States)

    Kooyman, Leslie; Pierce, Gloria; Zavadil, Amy

    2011-01-01

    Hooking up generally involves casual sex with noncommittal partners. Hooking up is prevalent on college campuses today and can negatively affect the identity development of female students. The authors examined this phenomenon with a feminist developmental perspective, evaluating hooking up in the context of sexual risk taking with physical and…

  16. Double-hook retractor for microlumbar discectomy and foraminotomy

    Directory of Open Access Journals (Sweden)

    Parthiban J

    2004-01-01

    Full Text Available Aiming to achieve better results in microlumbar discectomy and foraminotomy, a double-hook retractor has been designed to retract lumbar paraspinal muscles away from the spinous process. A double-hook retractor obviates the limitations of single-hook systems.

  17. Education as a Practice of Freedom: Reflections on bell hooks

    Science.gov (United States)

    Specia, Akello; Osman, Ahmed A.

    2015-01-01

    This paper critically analyses the conceptions of bell hooks on education. It focuses on the relevance of hook's ideas to the classroom. It is a theoretical paper based on secondary data that seeks to contribute to the growing body of knowledge in education. The paper is a reflection of hook's reaction to education as a practice of freedom, the…

  18. Postpartum Blues

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    Full Text Available ... Quality Collaboratives Launch Prematurity research centers What is team science? More than 75 years of solving problems ... delivery cause the postpartum blues. How can you manage the baby blues? The American College of Obstetricians ...

  19. Postpartum Blues

    Medline Plus

    Full Text Available ... with this condition are happy most of the time. But compared to how she usually feels, the ... the "blues" usually lessens and goes away over time. What causes the baby blues? Medical experts believe ...

  20. Postpartum Blues

    Medline Plus

    Full Text Available ... Postpartum care > The postpartum blues The postpartum blues E-mail to a friend Please fill in all fields. Please enter a valid e-mail address. Your information: Your recipient's information: Your ...

  1. Postpartum Blues

    Medline Plus

    Full Text Available ... can you manage the baby blues? The American College of Obstetricians and Gynecologists recommends that women do ... can you manage the baby blues? The American College of Obstetricians and Gynecologists recommends that women do ...

  2. Postpartum Blues

    Medline Plus

    Full Text Available ... Feels sad Feels confused The postpartum blues peak three to five days after delivery. They usually end ... Feels sad Feels confused The postpartum blues peak three to five days after delivery. They usually end ...

  3. Postpartum Blues

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    Full Text Available ... postpartum blues The postpartum blues E-mail to a friend Please fill in all fields. Please enter ... hear about breakthroughs for babies and families. Ask a question Our health experts can answer questions about ...

  4. Postpartum Blues

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    Full Text Available ... Medical experts believe that changes in the woman's hormones after delivery cause the postpartum blues. How can ... Medical experts believe that changes in the woman's hormones after delivery cause the postpartum blues. How can ...

  5. CARMA Survey Toward Infrared-bright Nearby Galaxies (STING) II: Molecular Gas Star Formation Law and Depletion Time Across the Blue Sequence

    CERN Document Server

    Rahman, Nurur; Xue, Rui; Wong, Tony; Leroy, Adam K; Walter, Fabian; Bigiel, Frank; Rosolowsky, Erik; Fisher, David B; Vogel, Stuart N; Blitz, Leo; West, Andrew A; Ott, Juergen

    2011-01-01

    We present an analysis of the relationship between molecular gas and current star formation rate surface density at sub-kpc and kpc scales in a sample of 14 nearby star-forming galaxies. Measuring the relationship in the bright, high molecular gas surface density ($\\Shtwo\\gtrsim$20 \\msunpc) regions of the disks to minimize the contribution from diffuse extended emission, we find an approximately linear relation between molecular gas and star formation rate surface density, $\

  6. cptnHook - Summer Student Project Report

    CERN Document Server

    Asimakopoulou, Eleni - Myrto

    2015-01-01

    The present is a report of the work that was conducted during my 8-week summer school internship at CERN. The project was centered on the development of an instrumentation tool for the usage of mathematical functions in a scientific application. More specifically, $\\textbf{cptnHook}$ addresses a current issue that arises from the the extensive use of very time-consuming mathematical functions (such as transcendental functions) that results in them accounting for a big portion of their run-time. It is believed that the problem can be addressed with ad-hoc approximations of mathematical functions, for which a clear overview of the usage of the functions in the program is required. $\\textbf{cptnHook}$ approaches this problem by providing a measurement of the use of mathematical functions in a program by hooking into the machine code and probing the arguments of the functions, without modifying the application's source code. The outputs of the tool are provided in ROOT format for further on analysis.

  7. 基于ITIL标准的移动变更与配置管理系统研究与实现%ITIL-Compliant Mobility Change and Configuration Management in BlueStar

    Institute of Scientific and Technical Information of China (English)

    刘培妮; 刘亮; 陈杨; 王浩

    2009-01-01

    With the rapid growth of powerful mobile devices.to improve the speed and quality of customer service,mobilizing their workforce became more and more important tO many companies.Consequently,all kinds of enterprise applications,policies and data access ale enabled through mobile platforms.However,how to manage such various mobile types and mobile applications and to integrate them with existing enterprise IT infrastructure becomes a great challenge.In this paper,we propose a novel approach to manage the enterprise mobiles through IT service management by using standard ITIL processes.Motivated by real cases of insurance industry mobile solution,firstly,a system architecture named BlueStar iS designed which integrated ITIL-compliant mobile management and enterprise IT service management into a uniform platform.Secondly,typical ITIL processes and best practices:Change and configuration workflow ale introduced for mobility management.Thirdly,the BlueStar system included device management component is implemented and evaluated by the motivating cases.

  8. Hook-Up Sexual Experiences and Problem Behaviors among Adolescents

    Science.gov (United States)

    Fortunato, Leanna; Young, Amy M.; Boyd, Carol J.; Fons, Courtney E.

    2010-01-01

    This study focuses on the sexual phenomenon of "hooking up." A hook-up is defined as a single sexual encounter that may or may not include sexual intercourse with someone who is a stranger, brief acquaintance, or friend. The aim of this study was to document the prevalence of hook-ups in a sample of 1,011 urban middle and high school students and…

  9. KELT-2Ab: A Hot Jupiter Transiting the Bright (V=8.77) Primary Star of a Binary System

    CERN Document Server

    Beatty, Thomas G; Siverd, Robert J; Eastman, Jason D; Bieryla, Allyson; Latham, David W; Buchhave, Lars A; Jensen, Eric L N; Manner, Mark; Stassun, Keivan G; Gaudi, B Scott; Berlind, Perry; Calkins, Michael L; Collins, Karen; DePoy, Darren L; Esquerdo, Gilbert A; Fulton, Benjamin J; Fűrész, Gábor; Geary, John C; Gould, Andrew; Hebb, Leslie; Kielkopf, John F; Marshall, Jennifer L; Pogge, Richard; Stanek, K Z; Stefanik, Robert P; Street, Rachel; Szentgyorgyi, Andrew H; Trueblood, Mark; Trueblood, Patricia; Stutz, Amelia M

    2012-01-01

    We report the discovery of KELT-2Ab, a hot Jupiter transiting the bright (V=8.77) primary star of the HD 42176 binary system. The host is a slightly evolved late F-star likely in the very short-lived "blue-hook" stage of evolution, with $\\teff=6151\\pm50{\\rm K}$, $\\log{g_*}=4.030_{-0.028}^{+0.013}$ and $\\feh=-0.018\\pm0.069$. The inferred stellar mass is $M_*=1.308_{-0.025}^{+0.028}$\\msun\\ and the star has a relatively large radius of $R_*=1.828_{-0.034}^{+0.070}$\\rsun. The planet is a typical hot Jupiter with period $4.113791\\pm0.00001$ days and a mass of $M_P=1.522\\pm0.078$\\mj\\ and radius of $R_P=1.286_{-0.047}^{+0.065}$\\rj. This is mildly inflated as compared to models of irradiated giant planets at the $\\sim$4 Gyr age of the system. KELT-2A is the third brightest star with a transiting planet identified by ground-based transit surveys, and the ninth brightest star overall with a transiting planet. KELT-2Ab's mass and radius are unique among the subset of planets with $V<9$ host stars, and therefore incre...

  10. Hook nozzle arrangement for supporting airfoil vanes

    Science.gov (United States)

    Shaffer, James E.; Norton, Paul F.

    1996-01-01

    A gas turbine engine's nozzle structure includes a nozzle support ring, a plurality of shroud segments, and a plurality of airfoil vanes. The plurality of shroud segments are distributed around the nozzle support ring. Each airfoil vane is connected to a corresponding shroud segment so that the airfoil vanes are also distributed around the nozzle support ring. Each shroud segment has a hook engaging the nozzle support ring so that the shroud segments and corresponding airfoil vanes are supported by the nozzle support ring. The nozzle support ring, the shroud segments, and the airfoil vanes may be ceramic.

  11. Kind of Blue - Europa Blues

    DEFF Research Database (Denmark)

    Mortensen, Tore; Kirkegaard, Peter

    2009-01-01

    Bidraget reflekterer over sammenhænge mellem to værker fra det musikalske og litterære område. Det drejer sig om Miles Davis' Kind of Blue fra 1959 og Arne Dahls krimi, Europa Blues fra 2001. Den grundlæggende indfaldsvinkel er det performative, den frie, men samtidigt disciplinerede musikalske...

  12. Canine retraction with J hook headgear.

    Science.gov (United States)

    Ayala Perez, C; de Alba, J A; Caputo, A A; Chaconas, S J

    1980-11-01

    Several methods have been described for accomplishing distal movement of canines without losing posterior anchorage. An accepted method in canine retraction is the use of headgear with J hooks. Since it incorporates extraoral anchorage, it is most effective in maximum-anchorage cases. It was the purpose of this study to analyze the distribution of force transmitted to the alveolus and surrounding structures by means of photoelastic visualization, utilizing J hook headgear for maxillary canine retraction. A three-dimensional model representing a human skull was used. This model was constructed with different birefringent materials to simulate bone, teeth, and periodontal membranes. Three different vectors of force were applied representing high-, medium-, and low-pull headgear, which were placed at angles of 40, 20, and 0 degrees to the occlusal plane. The photoelastic analysis was made by means of a circular-transmission polariscope arrangement, and the photoelastic data were recorded photographically. The stress areas created by the three different vectors of force were associated with various degrees of canine tipping. This effect was greater with the low-pull force component than with the medium-pull traction. The high-pull headgear produced the least tipping tendency, being closer to a bodily movemment effect. Further, stresses were transmitted to deeper structures of the simulated facial bones; these regions were the frontozygomatic, zygomaticomaxillary, and zygomaticotemporal sutures.

  13. Postpartum Blues

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    Full Text Available ... leader Partner Spotlight Become a partner World Prematurity Day Your support helps babies We are determined to ... confused The postpartum blues peak three to five days after delivery. They usually end by the tenth ...

  14. Postpartum Blues

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    Full Text Available ... Saving Just a moment, please. You've saved this page It's been added to your dashboard . After ... blues" is not really correct since women with this condition are happy most of the time. But ...

  15. Postpartum Blues

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    Full Text Available ... dashboard . After the baby is born, many new mothers have the postpartum blues (also called the baby ... compared to how she usually feels, the new mother: Is more irritable Cries more easily Feels sad ...

  16. Postpartum Blues

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    Full Text Available ... for your baby Feeding your baby Common illnesses New parents Family health & safety Complications & Loss Pregnancy complications ... your dashboard . After the baby is born, many new mothers have the postpartum blues (also called the ...

  17. Star formation and the interstellar medium in low surface brightness galaxies III. Why they are blue, thin and poor in molecular gas

    NARCIS (Netherlands)

    Gerritsen, JPE; de Blok, WJG

    1999-01-01

    We present N-body simulations of Low Surface Brightness (LSB) galaxies and their Interstellar Medium to investigate the cause for their low star formation rates (SFR). Due to their massive halos, stellar disks of LSB galaxies are very stable and thin. Lack of dust makes the projected edge-on surface

  18. KELT-2Ab: A HOT JUPITER TRANSITING THE BRIGHT (V = 8.77) PRIMARY STAR OF A BINARY SYSTEM

    International Nuclear Information System (INIS)

    We report the discovery of KELT-2Ab, a hot Jupiter transiting the bright (V = 8.77) primary star of the HD 42176 binary system. The host is a slightly evolved late F-star likely in the very short-lived 'blue-hook' stage of evolution, with Teff = 6148 ± 48 K, log g = 4.030+0.015–0.026 and [Fe/H] = 0.034 ± 0.78. The inferred stellar mass is M* = 1.314+0.063–0.060 M☉ and the star has a relatively large radius of R* = 1.836+0.066–0.046 R☉. The planet is a typical hot Jupiter with period 4.1137913 ± 0.00001 days and a mass of MP = 1.524 ± 0.088 MJ and radius of RP = 1.290+0.064–0.050 RJ. This is mildly inflated as compared to models of irradiated giant planets at the ∼4 Gyr age of the system. KELT-2A is the third brightest star with a transiting planet identified by ground-based transit surveys, and the ninth brightest star overall with a transiting planet. KELT-2Ab's mass and radius are unique among the subset of planets with V –1.

  19. Globular clusters in the blue compact galaxy ESO 338-IG04 (Tol 1924-416), as tracers of the star formation history. Results from HST/WFPC2 observations

    CERN Document Server

    Östlin, G A; Rönnback, J; Bergvall, Nils; Rönnback, Jari

    1998-01-01

    Multicolour images of the starbursting metal poor blue compact galaxy ESO338-IG04 have been obtained with WFPC2/HST. In the images we find numerous point-like sources concentrated towards the main body of the galaxy, which we identify as globular cluster candidates. We show that these objects are physically associated with the galaxy and that they are spatially extended. Given their high intrinsic luminosities, these objects cannot be individual stars. Using photometric evolution models we show that the objects constitute a rich population of massive star clusters with ages ranging from a few Myr to 10 Gyr, and masses ranging from 10^4 to more than 10^7 solar masses. We show that these objects are most likely globular clusters of varying age. There are peaks in the age distribution of the clusters: at <30 Myr, ~100 Myr, ~600 Myr, 2.5-5 Gyr and ~10 Gyr. The youngest objects are found in the crowded starburst region. The galaxy presently appears to be involved in a merger, which is the probable cause of the ...

  20. Structural insights into bacterial flagellar hooks similarities and specificities

    Science.gov (United States)

    Yoon, Young-Ho; Barker, Clive S.; Bulieris, Paula V.; Matsunami, Hideyuki; Samatey, Fadel A.

    2016-01-01

    Across bacteria, the protein that makes the flagellar hook, FlgE, has a high variability in amino acid residue composition and sequence length. We hereby present the structure of two fragments of FlgE protein from Campylobacter jejuni and from Caulobacter crescentus, which were obtained by X-ray crystallography, and a high-resolution model of the hook from Caulobacter. By comparing these new structures of FlgE proteins, we show that bacterial hook can be divided in two distinct parts. The first part comprises domains that are found in all FlgE proteins and that will make the basic structure of the hook that is common to all flagellated bacteria. The second part, hyper-variable both in size and structure, will be bacteria dependent. To have a better understanding of the C. jejuni hook, we show that a special strain of Salmonella enterica, which was designed to encode a gene of flgE that has the extra domains found in FlgE from C. jejuni, is fully motile. It seems that no matter the size of the hook protein, the hook will always have a structure made of 11 protofilaments. PMID:27759043

  1. Hooked: Habits of the Chinese Permian gigantopterid Gigantonoclea

    Science.gov (United States)

    Seyfullah, Leyla J.; Glasspool, Ian J.; Hilton, Jason

    2014-04-01

    Based upon anatomical evidence, Permian aged gigantopterid fossils are in general reconstructed as climbing or scrambling plants. Gigantonoclea, a genus of adpressed gigantopterid foliage from the Permian of northern China, has been reported to co-occur with hook-like organs that were interpreted as indicating a scrambling/climbing habit. We reinvestigated these hook-like structures and re-evaluated the nature of the co-occurrences in context with the flora preserved in each plant-bearing fossil 'bed' in the North China sedimentary succession. New findings show that the species Gigantonoclea hallei probably climbed using specially adapted clusters of compound grappling hook-like shoots borne on the stems. This structural arrangement comprising shoots of hooks is new to the scrambling/climbing concept in gigantopterids. However, a key figured specimen previously reported as showing intermediate hook-tipped leaf morphology on a sole pinnule tip is discounted as such and is reinterpreted as a 'normal' pinnule partially hidden under sediment that results in an unusual appearance to this pinnule tip. Adaptations for climbing or scrambling based upon 'hooked leaves' observed in Gigantonoclea lagrelii are no longer supported and are reinterpreted as incompletely expanded leaves where the vernation process was interrupted. These data weaken prior interpretations of G. lagrelii as a climber/scrambler and raise doubts about the ubiquity of hooks amongst the gigantopterids as structures enabling them to climb or scramble their way through the Permian world.

  2. Robert Hooke's Seminal Contribution to Orbital Dynamics

    Science.gov (United States)

    Nauenberg, Michael

    2005-03-01

    During the second half of the seventeenth century, the outstanding problem in astronomy was to understand the physical basis for Kepler’s laws describing the observed orbital motion of a planet around the Sun. In the middle 1660s,Robert Hooke (1635 1703) proposed that a planet’s motion is determined by compounding its tangential velocity with the change in radial velocity impressed by the gravitational attraction of the Sun, and he described his physical concept to Isaac Newton (1642 1726) in correspondence in 1679. Newton denied having heard of Hooke’s novel concept of orbital motion, but shortly after their correspondence he implemented it by a geometric construction from which he deduced the physical origin of Kepler’s area law,which later became Proposition I, Book I, of his Principia in 1687.Three years earlier, Newton had deposited a preliminary draft of it, his De Motu Corporum in Gyrum (On the Motion of Bodies), at the Royal Society of London, which Hooke apparently was able to examine a few months later, because shortly there-after he applied Newton’s construction in a novel way to obtain the path of a body under the action of an attractive central force that varies linearly with the distance from its center of motion (Hooke’s law). I show that Hooke’s construction corresponds to Newton’s for his proof of Kepler’s area law in his De Motu. Hooke’s understanding of planetary motion was based on his observations with mechanical analogs. I repeated two of his experiments and demonstrated the accuracy of his observations.My results thus cast new light on the significance of Hooke’s contributions to the development of orbital dynamics, which in the past have either been neglected or misunderstood.

  3. CARMA SURVEY TOWARD INFRARED-BRIGHT NEARBY GALAXIES (STING). II. MOLECULAR GAS STAR FORMATION LAW AND DEPLETION TIME ACROSS THE BLUE SEQUENCE

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Nurur; Bolatto, Alberto D.; Fisher, David B.; Vogel, Stuart N. [Department of Astronomy, University of Maryland, College Park, MD (United States); Xue Rui; Wong, Tony [Department of Astronomy, University of Illinois, Urbana-Champaign, IL (United States); Leroy, Adam K. [National Radio Astronomy Observatory, Charlottesville, VA (United States); Walter, Fabian [Max-Planck-Institute fur Astronomie, Heidelberg (Germany); Bigiel, Frank [Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, D-69120 Heidelberg (Germany); Rosolowsky, Erik [I. K. Barber School of the Arts and Science, University of British-Columbia, Kelowna, BC (Canada); Blitz, Leo [Department of Astronomy, University of California, Berkeley, CA (United States); West, Andrew A. [Department of Astronomy, Boston University, Boston, MA (United States); Ott, Juergen, E-mail: nurur@astro.umd.edu [National Radio Astronomy Observatory, Socorro, NM (United States)

    2012-02-01

    We present an analysis of the relationship between molecular gas and current star formation rate surface density at sub-kiloparsec and kiloparsec scales in a sample of 14 nearby star-forming galaxies. Measuring the relationship in the bright, high molecular gas surface density ({Sigma}{sub H{sub 2}}{approx}>20 M{sub Sun} pc{sup -2}) regions of the disks to minimize the contribution from diffuse extended emission, we find an approximately linear relation between molecular gas and star formation rate surface density, N{sub mol} {approx} 0.96 {+-} 0.16, with a molecular gas depletion time, {tau}{sup mol}{sub dep} {approx} 2.30 {+-} 1.32 Gyr. We show that in the molecular regions of our galaxies there are no clear correlations between {tau}{sup mol}{sub dep} and the free-fall and effective Jeans dynamical times throughout the sample. We do not find strong trends in the power-law index of the spatially resolved molecular gas star formation law or the molecular gas depletion time across the range of galactic stellar masses sampled (M{sub *} {approx} 10{sup 9.7}-10{sup 11.5} M{sub Sun }). There is a trend, however, in global measurements that is particularly marked for low-mass galaxies. We suggest that this trend is probably due to the low surface brightness CO J = 1-0, and it is likely associated with changes in CO-to-H{sub 2} conversion factor.

  4. Ionized Gas Kinematics at High Resolution V: [NeII], Multiple Clusters, High Efficiency Star Formation and Blue Flows in He 2-10

    CERN Document Server

    Beck, Sara C; Lacy, John; Greathouse, Thomas

    2015-01-01

    We measured the $12.8\\mu$m [NeII] line in the dwarf starburst galaxy He 2-10 with the high-resolution spectrometer TeXeS on the NASA IRTF. The data cube has diffraction-limited spatial resolution $\\sim1^{\\prime\\prime}$ and total velocity resolution including thermal broadening of $\\sim5$km/s. This makes it possible to compare the kinematics of individual star-forming clumps and molecular clouds in the three dimensions of space and velocity, and allows us to determine star formation efficiencies. The kinematics of the ionized gas confirm that the starburst contains multiple dense clusters. From the $M/R$ of the clusters and the $\\simeq30-40$% star formation efficiencies the clusters are likely to be bound and long lived, like globulars. Non-gravitational features in the line profiles show how the ionized gas flows through the ambient molecular material, as well as a narrow velocity feature which we identify with the interface of the HII region and a cold dense clump. These data offer an unprecedented view of t...

  5. IONIZED GAS KINEMATICS AT HIGH RESOLUTION. V. [Ne ii], MULTIPLE CLUSTERS, HIGH EFFICIENCY STAR FORMATION, AND BLUE FLOWS IN HE 2–10

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Sara [School of Physics and Astronomy, Tel Aviv University, Ramat Aviv 69978 (Israel); Turner, Jean [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095-1547 (United States); Lacy, John [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Greathouse, Thomas [Southwest Research Institute, San Antonio, TX 78228-0510 (United States)

    2015-11-20

    We measured the 12.8 μm [Ne ii] line in the dwarf starburst galaxy He 2–10 with the high-resolution spectrometer TEXES on the NASA IRTF. The data cube has a diffraction-limited spatial resolution of ∼1″ and a total velocity resolution, including thermal broadening, of ∼5 km s{sup −1}. This makes it possible to compare the kinematics of individual star-forming clumps and molecular clouds in the three dimensions of space and velocity, and allows us to determine star formation efficiencies. The kinematics of the ionized gas confirm that the starburst contains multiple dense clusters. From the M/R of the clusters and the ≃30%–40% star formation efficiencies, the clusters are likely to be bound and long lived, like globulars. Non-gravitational features in the line profiles show how the ionized gas flows through the ambient molecular material, as well as a narrow velocity feature, which we identify with the interface of the H ii region and a cold dense clump. These data offer an unprecedented view of the interaction of embedded H ii regions with their environment.

  6. High velocity blue-shifted FeII absorption in the dwarf star-forming galaxy PHL293B: Evidence for a wind driven supershell?

    CERN Document Server

    Terlevich, R; Bosch, G; Diaz, A I; Hagele, G; Cardaci, M; Firpo, V

    2014-01-01

    X-shooter and ISIS WHT spectra of the starforming galaxy PHL 293B also known as A2228-00 and SDSS J223036.79-000636.9 are presented in this paper. We find broad (FWHM = 1000km/s) and very broad (FWZI = 4000km/s) components in the Balmer lines, narrow absorption components in the Balmer series blueshifted by 800km/s, previously undetected FeII multiplet (42) absorptions also blueshifted by 800km/s, IR CaII triplet stellar absorptions consistent with [Fe/H] < -2.0 and no broad components or blushifted absorptions in the HeI lines. Based on historical records, we found no optical variability at the 5 sigma level of 0.02 mag between 2005 and 2013 and no optical variability at the level of 0.1mag for the past 24 years. The lack of variability rules out transient phenomena like luminous blue variables or SN IIn as the origin of the blue shifted absorptions of HI and FeII. The evidence points to either a young and dense expanding supershell or a stationary cooling wind, in both cases driven by the young cluster w...

  7. Ring on the hook: placing a ring on a moving and pendulating hook based on visual input

    DEFF Research Database (Denmark)

    Kjær-Nielsen, Anders; Buch, Anders Glent; Jensen, Andreas Kryger;

    2011-01-01

    Purpose – The purpose of this paper is to describe a robot vision system which put rings on hooks that are moving freely on a conveyor belt. The hook can show a significant swinging which can be well approximated by a pendulum movement. The problem is of large relevance for many industrial...... robot action. Findings – The authors achieve this through a precise pose estimation in a high-resolution stereo setup, as well as a modeling of the hook movement as a combination of a translational and a pendulum movement. Originality/value – The paper shows that under normal conditions close to 100...

  8. Blue gods, blue oil, and blue people.

    Science.gov (United States)

    Fairbanks, V F

    1994-09-01

    Studies of the composition of coal tar, which began in Prussia in 1834, profoundly affected the economies of Germany, Great Britain, India, and the rest of the world, as well as medicine and surgery. Such effects include the collapse of the profits of the British indigo monopoly, the growth in economic power of Germany based on coal tar chemistry, and an economic crisis in India that led to more humane tax laws and, ultimately, the independence of India and the end of the British Empire. Additional consequences were the development of antiseptic surgery and the synthesis of a wide variety of useful drugs that have eradicated infections and alleviated pain. Many of these drugs, particularly the commonly used analgesics, sulfonamides, sulfones, and local anesthetics, are derivatives of aniline, originally called "blue oil" or "kyanol." Some of these aniline derivatives, however, have also caused aplastic anemia, agranulocytosis, and methemoglobinemia (that is, "blue people"). Exposure to aniline drugs, particularly when two or three aniline drugs are taken concurrently, seems to be the commonest cause of methemoglobinemia today. PMID:8065194

  9. Prime Hook NWR Marsh Restoration Project Summary & Monitoring Plan 2015

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This living document provides a condensed explanation of wetland management history and a large-scale tidal marsh restoration project at Prime Hook NWR in Delaware....

  10. Narrative Report: Bombay Hook National Wildlife Refuge 1975

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Bombay Hook National Wildlife Refuge outlines Refuge accomplishments during the 1975 fiscal year. The report begins by summarizing...

  11. Narrative report : Bombay Hook National Wildlife Refuge : September - December 1953

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Bombay Hook NWR outlines Refuge accomplishments from September through December of 1953. The report begins by summarizing the weather...

  12. Post-hooking survival of loggerheads in the NED

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We deployed pop-off archival transmitting tags on 15 loggerhead turtles that had been hooked in the U.S. pelagic longline fishery and on 10 loggerheads that had...

  13. Narrative report Prime Hook National Wildlife Refuge: January - December, 1971

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Prime Hook National Wildlife Refuge outlines Refuge accomplishments during the 1971 calendar year. The report begins by summarizing...

  14. Water Management Plan: Bombay Hook National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Bombay Hook National Wildlife Refuge Water Management Plan has been developed to meet the station objectives set forth in the Master Plan. The purpose of this...

  15. Kolmanda aastatuhande piraadid / kommenteerinud Peter Chalk ja Gordan Van Hook

    Index Scriptorium Estoniae

    2009-01-01

    Piraatlusest Somaalia piirkonnas ja rahvusvahelistest dokumentidest piraatluse vastu võitlemiseks 21. sajandil. Kommenteerivad uurimiskeskuse RAND Corporation vanempoliitanalüütik Peter Chalk ja transpordikompanii Maersk Line innovatsiooni ja arenduse vanemdirektor Gordan Van Hook

  16. Prime Hook National Wildife Refuge Annual Narrative 1972

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Prime Hook National Wildlife Refuge outlines Refuge accomplishments during the 1972 calendar year. The report begins by summarizing...

  17. De Novo Synthesis of Phytochrome in Pumpkin Hooks 1

    Science.gov (United States)

    Quail, P. H.; Schäfer, E.; Marmé, D.

    1973-01-01

    Phytochrome becomes density labeled in the hook of pumpkin (Cucurbita pepo L.) seedlings grown in the dark on D2O, indicating that the protein moiety of the pigment is synthesized de novo during development. Red light causes a rapid decline of the total phytochrome level in the hook of etiolated seedlings but upon return to the dark, phytochrome again accumulates. These newly appearing molecules are also synthesized de novo. Newly synthesized phytochrome in both dark-grown and red-irradiated seedlings is in the red-absorbing form. Turnover of the red-absorbing form is indicated by the density labeling of phytochrome during a period when the total phytochrome level in the hook of dark-grown seedlings remains constant. However, it was not possible to determine whether this results from intracellular turnover or turnover of the whole cell population during hook growth. PMID:16658511

  18. James J. Howard Marine Sciences Laboratory @ Sandy Hook

    Data.gov (United States)

    Federal Laboratory Consortium — The James J. Howard Marine Sciences Laboratory, located on the New Jersey shore at Sandy Hook, is a state-of-the-art marine research facility shared by the National...

  19. Water Management Program Report 1980 Bombay Hook National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual program describes the results of the 1979 water management program at Bombay Hook National Wildlife Refuge and outlines the water regimen plan for 1980....

  20. Water Management Program Report 1979 Bombay Hook National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual program describes the results of the 1978 water management program at Bombay Hook National Wildlife Refuge and outlines the water regimen plan for 1979....

  1. Relationship between tornadoes and hook echoes on April 3, 1974

    Science.gov (United States)

    Forbes, G. S.

    1975-01-01

    Radar observations of tornado families occurring on April 3, 1974 are discussed. Of the 93 tornadoes included in the sample, 81% were associated with hook-like echoes with appendages at least 40 deg to the south of the echo movement. At least one tornado was associated with 62% of the hook-like echoes observed. All of the tornadoes with intensities of F 4 and F 5 were produced by hook-like echoes; the mean intensity of all tornadoes associated with this type of echo was F 3, while the mean intensity of the remaining tornadoes was F1. The tornadic hook-like echoes moved to the right of the non-tornadic echoes forming a tornado line in advance of the squall line. Some tornadoes were associated with 'spiral' echoes.

  2. Animal Control Plan Prime Hook National Wildlife Refuge 1987

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document contains a discussion of programs of the refuge as they relate to animal control and plans for managing these resources at Prime Hook National...

  3. Introduction Management Plan Prime Hook National Wildlife Refuge 1987

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a detailed outline of the Prime Hook National Wildlife Refuge that includes information on the following topics: Location, History of the Refuge,...

  4. General wilderness correspondence [Bombay Hook National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a collection of correspondence pertaining to the Bombay Hook National Wildlife Refuge Wilderness proposal. Many of the letters concern mosquito...

  5. Prime Hook National Wildlife Refuge Annual Narrative Fiscal Year 1974

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Prime Hook National Wildlife Refuge outlines Refuge accomplishments during the 1974 fiscal year. The report begins by summarizing...

  6. Narrative report : Bombay Hook National Wildlife Refuge : May - August 1961

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Bombay Hook NWR outlines Refuge accomplishments from May through August of 1961. The report begins by summarizing the weather conditions,...

  7. Narrative report : Bombay Hook National Wildlife Refuge : May - August 1959

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Bombay Hook NWR outlines Refuge accomplishments from May through August of 1959. The report begins by summarizing the weather conditions,...

  8. Narrative report : Bombay Hook National Wildlife Refuge : May - August 1958

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Bombay Hook NWR outlines Refuge accomplishments from May through August of 1958. The report begins by summarizing the weather conditions,...

  9. Narrative report : Bombay Hook National Wildlife Refuge : May - August 1960

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Bombay Hook NWR outlines Refuge accomplishments from May through August of 1960. The report begins by summarizing the weather conditions,...

  10. Narrative report : Bombay Hook National Wildlife Refuge : May - August 1962

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Bombay Hook NWR outlines Refuge accomplishments from May through August of 1962. The report begins by summarizing the weather conditions,...

  11. Narrative report : Bombay Hook National Wildlife Refuge : January - December, 1965

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Bombay Hook NWR outlines Refuge accomplishments during the 1965 calendar year. The report begins by summarizing the weather...

  12. Annual Narrative Report: Bombay Hook National Wildlife Refuge 1992

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Bombay Hook National Wildlife Refuge outlines Refuge accomplishments during the 1992 calendar year. The report begins with a...

  13. Sleep Loses Out for Many Hooked on Video Games

    Science.gov (United States)

    ... html Sleep Loses Out for Many Hooked on Video Games Willingness to delay bedtime may point to addiction, ... 2016 FRIDAY, June 17, 2016 (HealthDay News) -- Are video games like "Bloodborne," "Fallout" and "Call of Duty" worth ...

  14. Topology of the elliptical billiard with the Hooke's potential

    Directory of Open Access Journals (Sweden)

    Radnović Milena

    2015-01-01

    Full Text Available Using Fomenko graphs, we present a topological description of the elliptical billiard with Hooke's potential. [Projekat Ministarstva nauke Republike Srbije, br. 174020: Geometry and Topology of Manifolds and Integrable Dynamical Systems

  15. Water Management Program Report 1981 Bombay Hook National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual program describes the results of the 1980 water management program at Bombay Hook National Wildlife Refuge and outlines the water regimen plan for 1981....

  16. Fire Management Plan: Bombay Hook National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan considers fire on Bombay Hook National Wildlife Refuge as a tool for management and as a potential problem to be dealt with. This document discusses...

  17. Prescribed Fire Plan: Bombay Hook National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan considers fire on Bombay Hook National Wildlife Refuge as a tool for management and as a potential problem to be dealt with. This document discusses...

  18. Interim Land Use Plan Prime Hook National Wildlife Refuge 1967

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The continued grazing of cattle on grasslands and marsh acquired by the Prime Hook National Wildlife Refuge will be designed to retard the development of...

  19. Bohlin transformation: the hidden symmetry that connects Hooke to Newton

    Science.gov (United States)

    Saggio, Maria Luisa

    2013-01-01

    Hooke's name is familiar to students of mechanics thanks to the law of force that bears his name. Less well-known is the influence his findings had on the founder of mechanics, Isaac Newton. In a lecture given some twenty years ago, W Arnol'd pointed out the outstanding contribution to science made by Hooke, and also noted the controversial issue of the attribution of important discoveries to Newton that were actually inspired by Hooke. It therefore seems ironic that the two most famous force laws, named after Hooke and Newton, are two geometrical aspects of the same law. This relationship, together with other illuminating aspects of Newtonian mechanics, is described in Arnol'd's book and is worth remembering in standard physics courses. In this didactical paper the duality of the two forces is expounded and an account of the more recent contributions to the subject is given.

  20. Wildlife Inventory Plan Bombay Hook National Wildlife Refuge 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Bombay Hook National Wildlife Refuge was established for the preservation of the waterfowl resource. The refuge is still managed principally for the benefit of...

  1. Wildlife Inventory Plan Bombay Hook National Wildlife Refuge 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Bombay Hook National Wildlife Refuge was established for the preservation of the waterfowl resource. The refuge is still managed principally for the benefit of...

  2. Wildlife Inventory Plan Bombay Hook National Wildlife Refuge 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Bombay Hook National Wildlife Refuge was established for the preservation of the waterfowl resource. The refuge is still managed principally for the benefit of...

  3. Atmospheric NLTE-Models for the Spectroscopic Analysis of Blue Stars with Winds. III. X-ray emission from wind-embedded shocks

    CERN Document Server

    Carneiro, Luiz P; Sundqvist, J O; Hoffmann, T L

    2016-01-01

    X-rays/EUV radiation emitted from wind-embedded shocks in hot, massive stars can affect the ionization balance in their outer atmospheres, and can be the mechanism responsible for the production of highly ionized species. To allow for these processes in the context of spectral analysis, we have implemented such emission into our unified, NLTE model atmosphere/spectrum synthesis code FASTWIND. The shock structure and corresponding emission is calculated as a function of user-supplied parameters. We account for a temperature and density stratification inside the post-shock cooling zones, calculated for radiative and adiabatic cooling in the inner and outer wind, respectively. The high-energy absorption of the cool wind is considered by adding important K-shell opacities, and corresponding Auger ionization rates have been included into the NLTE network. We tested and verified our implementation carefully against corresponding results from various alternative model atmosphere codes, and studied the effects from s...

  4. Atmospheric NLTE models for the spectroscopic analysis of blue stars with winds. III. X-ray emission from wind-embedded shocks

    Science.gov (United States)

    Carneiro, L. P.; Puls, J.; Sundqvist, J. O.; Hoffmann, T. L.

    2016-05-01

    Context. Extreme ultraviolet (EUV) and X-ray radiation emitted from wind-embedded shocks in hot, massive stars can affect the ionization balance in their outer atmospheres and can be the mechanism responsible for producing highly ionized atomic species detected in stellar wind UV spectra. Aims: To allow for these processes in the context of spectral analysis, we have implemented the emission from wind-embedded shocks and related physics into our unified, NLTE model atmosphere/spectrum synthesis code FASTWIND. Methods: The shock structure and corresponding emission is calculated as a function of user-supplied parameters (volume filling factor, radial stratification of shock strength, and radial onset of emission). We account for a temperature and density stratification inside the postshock cooling zones, calculated for radiative and adiabatic cooling in the inner and outer wind, respectively. The high-energy absorption of the cool wind is considered by adding important K-shell opacities, and corresponding Auger ionization rates have been included in the NLTE network. To test our implementation and to check the resulting effects, we calculated a comprehensive model grid with a variety of X-ray emission parameters. Results: We tested and verified our implementation carefully against corresponding results from various alternative model atmosphere codes, and studied the effects from shock emission for important ions from He, C, N, O, Si, and P. Surprisingly, dielectronic recombination turned out to play an essential role for the ionization balance of O iv/O v (particularly in dwarfs with Teff~ 45 000 K). Finally, we investigated the frequency dependence and radial behavior of the mass absorption coefficient, κν(r), which is important in the context of X-ray line formation in massive star winds. Conclusions: In almost all of the cases considered, direct ionization is of major influence because of the enhanced EUV radiation field, and Auger ionization only affects N vi

  5. Ecological adaptations of Hypocyrta glabra Hook. flowers

    Directory of Open Access Journals (Sweden)

    Mychajło Czernećkyj

    2012-12-01

    Full Text Available The research on the blooming ecology and the flower morphology of Hypocyrta glabra Hook. (Gesneriaceae cultivated in laboratories and outdoors have been carried out. The life span of flowers and morphological changes in successive phases of the blooming period have been observed. The H. glabra flowers are protandrous and the stamens translocate during the flowering process. The macro- and microstructure of calyx, corolla, androecium, gynoecium and nectaries have been analyzed. The size, shape and viability of pollen grains have been designated and their number per stamen head has been calculated. The location of nectaries in H. glabra flowers has suggested that they stem from the 5th stamen during phylogenesis. It has been proved that the nectaries are provided by numerous vascular bundles and that the nectar is secreted by stomata. The stomatal field comprises 2/5 of nectary height and is situated on the abaxial side of the apix part. The average number of stomata is 63.2 per 1 mm2. The average amount of nectar produced by 10 flowers in their fourth day of life reached 223.7 mg. The sugar concentration was 32.7%. Numerous glandular and non-glandular trichomes have been noticed on the surface of calyx, corolla and gynoecium, which indicate the xeromorphic adaptation of the flower. It has been observed that the numbers of glandular and non-glandular trichomes per unit of the external surface of corolla are similar. Outdoors the secretion produced by calyx and corolla glands was willingly collected by wasps. It seems that such features of H. glabra flowers as position, shape and colour of corolla, the abundance of the nectar and pollen produced are connected with their adaptation to pollination by humming-birds in the species natural environment.

  6. Posthuman blues

    CERN Document Server

    Tonnies, Mac

    2013-01-01

    Posthuman Blues, Vol. I is first volume of the edited version of the popular weblog maintained by author Mac Tonnies from 2003 until his tragic death in 2009. Tonnies' blog was a pastiche of his original fiction, reflections on his day-to-day life, trenchant observations of current events, and thoughts on an eclectic range of material he culled from the Internet. What resulted was a remarkably broad portrait of a thoughtful man and the complex times in which he lived, rendered with intellige...

  7. Hook whistlers observed at low latitude ground station Varanasi

    International Nuclear Information System (INIS)

    Employing the Haselgrove ray tracing equations and a diffusive equilibrium model of the ionosphere, the propagation characteristics of hook whistlers recorded at low-latitude ground station Varanasi (geomag. lat., 1606'N) are discussed. It is shown that the two traces of the hook whistlers are caused by the VLF waves radiated from the return stroke of a lightning discharge which after penetrating the ionosphere at two different entry points, propagated to the opposite hemisphere in the whistler mode and were received at 16 geomagnetic latitude. Further the crossing of ray paths for the same frequency leads to the explanation of the hook whistler. The lower and higher cut-off frequencies are explained in terms of their deviating away from the bunch of the recorded whistler waves and crossing of ray paths for the same frequency. (Auth.)

  8. NOAA orthorectified Digital Elevation Model (DEM) image tiles, Bombay Hook, Delaware, 2011 (NODC Accession 0112173)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Bombay Hook Project covers 177 square kilometers of the Bombay Hook National Wildlife Refuge and surrounding areas in Kent County, Delaware. The Dewberry...

  9. Hook or hatchet – Lover 's Lane, love scene epilogue

    OpenAIRE

    Ivan Kovačević

    2016-01-01

    Myth of a couple who escape death in a chance encounter with the psychopath with a hook instead of a hand, is one of the ten classic urban legends that have been brought to public attention by folklorists during the sixth and seventh decade of the twentieth century. Eminent Anglo-American folklorists dedicated entire papers, or significant portion in their works to this tale, as a contribution to the study of urban legends as a folk genre. In this essay, the legend of the hook is closely link...

  10. Grindr, hook-up apps, og medialiseringen as offentlig sexkultur

    OpenAIRE

    Jørgensen, Kristian Møller

    2016-01-01

    The mediatization of public sex cultures in the case of the hook-up app Grindr Along with the normalisation of geo-locative dating and hook-up practices in mainstream publics – through apps like Tinder, Bumble and Happn – imaginations of sexual privacy and indeed publicness seem to be changing. This paper focuses on the interplay between media and public sex cultures in the case of the Grindr app use in gay male intimacy cultures. Though gay men’s sex practices, vis-à-vis cruising, have histo...

  11. Problem in Two Unknowns: Robert Hooke and a Worm in Newton's Apple.

    Science.gov (United States)

    Weinstock, Robert

    1992-01-01

    Discusses the place that Robert Hooke has in science history versus the scientific contributions he made. Examines the relationship between Hooke and his contemporary, Isaac Newton, and Hooke's claims that Newton built on his ideas without receiving Newton's recognition. (26 references) (MDH)

  12. Color vision: retinal blues.

    Science.gov (United States)

    Johnston, Jamie; Esposti, Federico; Lagnado, Leon

    2012-08-21

    Two complementary studies have resolved the circuitry underlying green-blue color discrimination in the retina. A blue-sensitive interneuron provides the inhibitory signal required for computing green-blue color opponency.

  13. Galanthus elwesii Hook. f. in de provincie Utrecht

    NARCIS (Netherlands)

    Raamsdonk, van L.W.D.

    1982-01-01

    Galanthus elwesii Hook. f. was first found in the Netherlands in 1941. Up to now only two country seats are known where G. elwesii is still growing, one of them being in the province of Utrecht. This paper deals with the occurrence of four new localities in the province of Utrecht, where O. elwesii

  14. Demo 34. Ley de Hooke con dinamómetros

    OpenAIRE

    Martínez Tomás, María del Carmen

    2013-01-01

    Objetivo: Comprobar la ley de Hooke cuando se alarga un muelle por el efecto de una fuerza (elasticidad por tracción). Comprobar que cuando se calibra este desplazamiento, un muelle puede servir como dinamómetro (se pueden medir directamente fuerzas).

  15. School Safety in a Post-Sandy Hook World

    Science.gov (United States)

    Trump, Kenneth S.

    2014-01-01

    In this report the author, who is a school safety expert, provides information about school safety in a post-Sandy Hook world. He presents the following: (1) Continuum of Threats and Responses; (2) The role social media plays; (3) Reliable Best Practices; (4) Policy and Funding--Climate and Context; (5) Policy and Funding--Things to Avoid; and (6)…

  16. Hooking up: gender differences, evolution, and pluralistic ignorance.

    Science.gov (United States)

    Reiber, Chris; Garcia, Justin R

    2010-01-01

    "Hooking-up"--engaging in no-strings-attached sexual behaviors with uncommitted partners--has become a norm on college campuses, and raises the potential for disease, unintended pregnancy, and physical and psychological trauma. The primacy of sex in the evolutionary process suggests that predictions derived from evolutionary theory may be a useful first step toward understanding these contemporary behaviors. This study assessed the hook-up behaviors and attitudes of 507 college students. As predicted by behavioral-evolutionary theory: men were more comfortable than women with all types of sexual behaviors; women correctly attributed higher comfort levels to men, but overestimated men's actual comfort levels; and men correctly attributed lower comfort levels to women, but still overestimated women's actual comfort levels. Both genders attributed higher comfort levels to same-gendered others, reinforcing a pluralistic ignorance effect that might contribute to the high frequency of hook-up behaviors in spite of the low comfort levels reported and suggesting that hooking up may be a modern form of intrasexual competition between females for potential mates. PMID:22947808

  17. Analytical Model for Hook Anchor Pull-out

    DEFF Research Database (Denmark)

    Brincker, Rune; Ulfkjær, J. P.; Adamsen, P.;

    A simple analytical model for the pull-out of a hook anchor is presented. The model is based on a simplified version of the fictitious crack model. It is assumed that the fracture process is the pull-off of a cone shaped concrete part, simplifying the problem by assuming pure rigid body motions...

  18. Analytical Model for Hook Anchor Pull-Out

    DEFF Research Database (Denmark)

    Brincker, Rune; Ulfkjær, J. P.; Adamsen, P.;

    1995-01-01

    A simple analytical model for the pull-out of a hook anchor is presented. The model is based on a simplified version of the fictitious crack model. It is assume that the fracture process is the pull-off of a cone shaped concrete part, simplifying the problem by assuming pure rigid body motions...

  19. Usefulness of Kent retractor and lifting hook for Nuss procedure.

    Science.gov (United States)

    Takahashi, Tsubasa; Okazaki, Tadaharu; Yamataka, Atsuyuki; Uchida, Eiji

    2015-11-01

    Although the Nuss procedure for pectus excavatum has been widely employed, a variety of complications have been reported. The most dangerous complication is cardiac injury from the insertion of the introducer. To eliminate these complications, we present a sternum elevating technique using a Kent retractor and a lifting hook.

  20. Ureteral stent retrieval using the crochet hook technique in females.

    Directory of Open Access Journals (Sweden)

    Takashi Kawahara

    Full Text Available INTRODUCTION: We developed a method for ureteral stent removal in female patients that requires no cystoscopy or fluoroscopic guidance using a crochet hook. In addition, we also investigated the success rate, complications and pain associated with this procedure. METHODS: A total of 40 female patients (56 stents underwent the removal of ureteral stents. All procedures were carried out with the patients either under anesthesia, conscious sedation, or analgesic suppositories as deemed appropriate for each procedure including Shock Wave Lithotripsy (SWL, Ureteroscopy (URS, Percutaneous Nephrolithotomy (PCNL, and ureteral stent removal. At the time of these procedures, fluoroscopy and/or cystoscopy were prepared, but they were not used unless we failed to successfully remove the ureteral stent using the crochet hook. In addition, matched controls (comprising 50 stents which were removed by standard ureteral stent removal using cystoscopy were used for comparison purposes. RESULTS: A total of 47 of the 56 stents (83.9% were successfully removed. In addition, 47 of 52 (90.4% were successfully removed except for two migrated stents and two heavily encrusted stents which could not be removed using cystoscopy. Ureteral stent removal using the crochet hook technique was unsuccessful in nine patients, including two encrustations and two migrations. Concerning pain, ureteral stent removal using the crochet hook technique showed a lower visual analogue pain scale (VAPS score than for the standard technique using cystoscopy. CONCLUSIONS: Ureteral stent removal using a crochet hook is considered to be easy, safe, and cost effective. This technique is also easy to learn and is therefore considered to be suitable for use on an outpatient basis.

  1. Modeling the Hook Depth Distribution of Pelagic Longlining in the Equatorial Area of Indian Ocean

    Institute of Scientific and Technical Information of China (English)

    SONG Liming; LI Jie; GAO Panfeng; ZHOU Ji; XU Liuxiong

    2012-01-01

    A survey was conducted in the equatorial area of Indian Ocean for a better understanding of the dynamics of hook depth distribution of pelagic longline fishery.We determined the relationship between hook depth and vertical shear of current coefficiency,wind speed,hook position code,sine of wind angle,sine of angle of attack and weight of messenger weight.We identified the hook depth models by the analysis of covariance with a general linear model.The results showed that the wind effect on the hook depth can be ignored from October to November in the survey area; the surface current effect on the hook depth can be ignored; the equatorial undercurrent is the key factor for the hook depth in Indian Ocean; and there is a negative correlation between the hook depth and vertical shear of current and angle of attack.It was also found that the deeper the hook was set,the higher hook depth shoaling was.The proposed model improves the accuracy of the prediction of hook depth,which can be used to estimate the vertical distribution of pelagic fish in water column.

  2. P Cygni: An Extraordinary Luminous Blue Variable

    OpenAIRE

    Israelian, G.; de Groot, M

    1999-01-01

    P Cygni is a prototype for understanding mass loss from massive stars. This textbook star is known first of all because of two great eruptions in the 17th century. In the first half of this century it has given its name to a class of stars which are characterized by spectral lines consisting of nearly undisplaced emissions accompanied by a blue-displaced absorption component. This characteristic P Cygni-type profile betrays the presence of a stellar wind, but P Cygni's wind is quite unlike th...

  3. Review: Derek Hook, A Critical Psychology of the Postcolonial: The Mind of Apartheid (2012 Buchbesprechung: Derek Hook, A Critical Psychology of the Postcolonial: The Mind of Apartheid (2012

    Directory of Open Access Journals (Sweden)

    Danielle Faye Tran

    2013-01-01

    Full Text Available Review of the monograph:Derek Hook, A Critical Psychology of the Postcolonial: The Mind of Apartheid, London: Routledge, 2012, ISBN 978-0-415-58757-0, 251 pagesBesprechung der Monographie:Derek Hook, A Critical Psychology of the Postcolonial: The Mind of Apartheid, London: Routledge, 2012, ISBN 978-0-415-58757-0, 251 Seiten

  4. Review: Derek Hook, A Critical Psychology of the Postcolonial: The Mind of Apartheid (2012) Buchbesprechung: Derek Hook, A Critical Psychology of the Postcolonial: The Mind of Apartheid (2012)

    OpenAIRE

    Danielle Faye Tran

    2013-01-01

    Review of the monograph:Derek Hook, A Critical Psychology of the Postcolonial: The Mind of Apartheid, London: Routledge, 2012, ISBN 978-0-415-58757-0, 251 pagesBesprechung der Monographie:Derek Hook, A Critical Psychology of the Postcolonial: The Mind of Apartheid, London: Routledge, 2012, ISBN 978-0-415-58757-0, 251 Seiten

  5. The effects of flagellar hook compliance on motility of monotrichous bacteria: A modeling study

    Science.gov (United States)

    Shum, H.; Gaffney, E. A.

    2012-06-01

    A crucial structure in the motility of flagellated bacteria is the hook, which connects the flagellum filament to the motor in the cell body. Early mathematical models of swimming bacteria assume that the helically shaped flagellum rotates rigidly about its axis, which coincides with the axis of the cell body. Motivated by evidence that the hook is much more flexible than the rest of the flagellum, we develop a new model that allows a naturally straight hook to bend. Hook dynamics are based on the Kirchhoff rod model, which is combined with a boundary element method for solving viscous interactions between the bacterium and the surrounding fluid. For swimming in unbounded fluid, we find good support for using a rigid model since the hook reaches an equilibrium configuration within several revolutions of the motor. However, for effective swimming, there are constraints on the hook stiffness relative to the scale set by the product of the motor torque with the hook length. When the hook is too flexible, its shape cannot be maintained and large deformations and stresses build up. When the hook is too rigid, the flagellum does not align with the cell body axis and the cell "wobbles" with little net forward motion. We also examine the attraction of swimmers to no-slip surfaces and find that the tendency to swim steadily close to a surface can be very sensitive to the combination of the hook rigidity and the precise shape of the cell and flagellum.

  6. Hook or hatchet – Lover 's Lane, love scene epilogue

    Directory of Open Access Journals (Sweden)

    Ivan Kovačević

    2016-02-01

    Full Text Available Myth of a couple who escape death in a chance encounter with the psychopath with a hook instead of a hand, is one of the ten classic urban legends that have been brought to public attention by folklorists during the sixth and seventh decade of the twentieth century. Eminent Anglo-American folklorists dedicated entire papers, or significant portion in their works to this tale, as a contribution to the study of urban legends as a folk genre. In this essay, the legend of the hook is closely linked with the boyfriend's' death legend, its hermetic interpretation, and contextualization in the social reality of sexual relations at the time in which it occurs.

  7. Information Entropy and Correlation of the Hooke's Atom

    CERN Document Server

    Atre, R; Panigrahi, P K; Atre, Rajneesh; Mohapatra, Chandra Shekhar; Panigrahi, Prasanta K.

    2004-01-01

    We provide an algebraic procedure to find the eigenstates of two-charged particles in an oscillator potential, known as {\\it{Hooke's}} atom. For the planar Hooke's atom, the exact eigenstates and single particle densities for arbitrary azimuthal quantum number, are obtained analytically. Information entropies associated with the wave functions for the relative motion are then studied systematically, since the same incorporates the effect of the Coulomb interaction. The {\\it{quantum pottery}} of the information entropy density reveals a number of intricate structures, which differ significantly for the attractive and repulsive cases. We indicate the procedure to obtain the approximate eigen states. Making use of the relationship of this dynamical system with the quasi-exactly solvable systems, one can also develop a suitable perturbation theory, involving the Coulomb coupling $Z$, for the approximate wave functions.

  8. Comparative HPTLC fingerprint profile of Illicium verum Hook.f. and Illicium griffithii Hook.f. & Thoms fruits

    Directory of Open Access Journals (Sweden)

    Saraswathy A

    2013-01-01

    Full Text Available Objective: To establish the fingerprint profile of two Illicium species namely Illicium verum Hook.f. and Illicium griffithii Hook.f. & Thoms using high performace thin layer chromatography (HPTLC technique. Methods: CAMAG HPTLC system equipped with TLC autosampler 4 applicator, TLC scanner 3 and win CATS 1.4.4. software was used. n-hexane, chloroform and ethyl acetate extracts of the fruits were developed in suitable mobile phase using standard procedures and scanned under UV at 254nm, 366 nm and under visible light. Results: The HPTLC fingerprinting of the n-hexane, chloroform and ethyl acetate extracts showed several peaks with different Rf values. Conclusion: HPTLC fingerprint profile of two Illicium species may be useful in differentiating the species and also helpful in the identification and authentication of these species

  9. A novel approach for removing the hook effect artefact from Electrical Bioimpedance spectroscopy measurements

    OpenAIRE

    Buendia, Ruben; Seoane, Fernando; Gil-Pita, Roberto

    2010-01-01

    Very often in Electrical Bioimpedance (EBI) spectroscopy measurements the presence of stray capacitances creates a measurement artefact commonly known as Hook Effect . Such an artefact creates a hook-alike deviation of the EBI data noticeable when representing the measurement on the impedance plane. Such Hook Effect is noticeable at high frequencies but it also causes a data deviation at lower measurement frequencies. In order to perform any accurate analysis of the EBI spectroscopy data, the...

  10. Blue cures blue but be cautious

    Directory of Open Access Journals (Sweden)

    Pranav Sikka

    2011-01-01

    Full Text Available Methemoglobinemia is a disorder characterized by the presence of >1% methemoglobin (metHb in the blood. Spontaneous formation of methemoglobin is normally counteracted by protective enzyme systems, for example, nicotinamide adenine dinucleotide phosphate (NADPH methemoglobin reductase. Methemoglobinemia is treated with supplemental oxygen and methylene blue (1-2 mg/kg administered slow intravenously, which acts by providing an artificial electron acceptor for NADPH methemoglobin reductase. But known or suspected glucose-6-phosphate dehydrogenase (G6PD deficiency is a relative contraindication to the use of methylene blue because G6PD is the key enzyme in the formation of NADPH through pentose phosphate pathway and G6PD-deficient individuals generate insufficient NADPH to efficiently reduce methylene blue to leukomethylene blue, which is necessary for the activation of the NADPH-dependent methemoglobin reductase system. So, we should be careful using methylene blue in methemoglobinemia patient before G6PD levels.

  11. A Comparative Study of Hooks in the Ya Rns Produced by Different Spinning Technologies

    Directory of Open Access Journals (Sweden)

    Ghosh Anindya

    2015-12-01

    Full Text Available This article presents a comparative study of hooks’ characteristics of ring, rotor, air-jet and open-end friction spun yarns. Hook types and their extent, spinning in-coefficient and mean fibre extent in the yarns produced on different spinning technologies are investigated. The results show that the hook extents for open-end friction spun yarn are the highest followed by rotor, ring and air-jet spun yarns. Ring and air-jet spun yarns have higher percentage and extent of trailing hook as compared with leading hook, whereas, rotor and friction spun yarns show the reverse trend.

  12. The evolution of circumstellar medium around rotating massive stars

    NARCIS (Netherlands)

    Chita, S.M.; Marle, A.J.; Langer, N.; García-Segura, G.

    2007-01-01

    A rotating 12Mȯ star, after its main-sequence evolution, becomes a redsupergiant when it starts core He burning. During core helium burning, as consequence of a variation of the hydrogen shell burning efficiency, the star undergoes a so called ``blue loop'', i.e. it evolves into a blue supergiant st

  13. Star Formation Regions in LDN 1667

    Science.gov (United States)

    Gyulbudaghian, A. L.

    2015-09-01

    A group of three star formation regions in the dark cloud LDN 1667 is examined. All three of these regions contain Trapezium type systems. 12C(1-0) observations are made of the part of the molecular cloud LDN 1667 associated with one of the star formation regions. Three molecular clouds were detected, one of which (the main cloud) has a red and a blue outflow. Three stars from the star formation regions are found to have annular nebulae and one star has a conical nebula. The dark cloud LDN 1667 is associated with a radial system of dark globules which is formed by the star HD 57061.

  14. Robert Hooke: early respiratory physiologist, polymath, and mechanical genius.

    Science.gov (United States)

    West, John B

    2014-07-01

    Robert Hooke (1635-1703) was a polymath who made important contributions to respiratory physiology and many other scientific areas. With Robert Boyle, he constructed the first air pump that allowed measurements on small animals at a reduced atmospheric pressure, and this started the discipline of high-altitude physiology. He also built the first human low-pressure chamber and described his experiences when the pressure was reduced to the equivalent of an altitude of ∼2,400 m. Using artificial ventilation in an animal preparation, he demonstrated that movement of the lung was not essential for life. His book Micrographia describing early studies with a microscope remains a classic. He produced an exquisite drawing of the head of a fly, showing the elaborate compound eye. There is also a detailed drawing of a flea, and Hooke noted how the long, many-jointed legs enable the insect to jump so high. For 40 years, he was the curator of experiments for the newly founded Royal Society in London and contributed greatly to its intellectual ferment. His mechanical inventions covered an enormous range, including the watch spring, the wheel barometer, and the universal joint. Following the Great Fire of London in 1666, he designed many of the new buildings in conjunction with Christopher Wren. Unfortunately, Hooke had an abrasive personality, which was partly responsible for a lack of recognition of his work for many years. However, during the last 25 years, there has been renewed interest, and he is now recognized as a brilliant scientist and innovator.

  15. An experimental 'Life' for an experimental life: Richard Waller's biography of Robert Hooke (1705).

    Science.gov (United States)

    Moxham, Noah

    2016-03-01

    Richard Waller's 'Life of Dr Robert Hooke', prefixed to his edition of Hooke's Posthumous Works (1705), is an important source for the life of one of the most eminent members of the early Royal Society. It also has the distinction of being one of the earliest biographies of a man of science to be published in English. I argue that it is in fact the first biography to embrace the subject's natural-philosophical work as the centre of his life, and I investigate Waller's reasons for adopting this strategy and his struggle with the problem of how to represent an early experimental philosopher in print. I suggest that Waller eschews the 'Christian philosopher' tradition of contemporary biography - partly because of the unusually diverse and fragmentary nature of Hooke's intellectual output - and draws instead upon the structure of the Royal Society's archive as a means of organizing and understanding Hooke's life. The most quoted phrase from Waller's biography is that Hooke became 'to a crime close and reserved' in later life; this essay argues that Waller's biographical sketch was fashioned in order to undo the effects of that reserve. In modelling his approach very closely on the structure of the society's records he was principally concerned with making Hooke's work and biography accessible, intelligible and useful to the fellowship in a context familiar to them, a context which had provided the institutional framework for most of Hooke's adult life. I argue that Waller's 'Life' was also intended to make the largest claims for Hooke's intellectual standing that the author dared in the context of the enmity between Hooke and Isaac Newton once the latter became president of the Royal Society. However, I also adduce fresh manuscript evidence that Waller actually compiled, but did not publish, a defence of Hooke's claim to have discovered the inverse square law of gravity, allowing us to glimpse a much more assertive biography of Hooke than the published version. PMID

  16. The influence of hook type, angler experience, and fish size on injury rates and the duration of capture in an Alaskan catch-and-release rainbow trout fishery

    Science.gov (United States)

    Meka, J.M.

    2004-01-01

    Owing to concerns about the high incidence of past hooking injuries in Alagnak River rainbow trout Oncorhynchus mykiss, fish were captured with spin- and fly-fishing gear with barbed and barbless circle and "J" hooks to determine gear types contributing to injury. Landing and hook removal times were measured for a portion of fish captured, and the anatomical hooking location, hooking scar locations, bleeding intensity, angler experience, and fish size were recorded for all captured fish. Approximately 62% of fish captured experienced at least one new hooking injury, and 29% of fish had at least one past hooking injury. Small fish sustained higher new injury and bleeding rates, but large fish had higher past injury rates. Injury rates were higher for barbed J hooks, barbed J hooks took longer to remove, and fish caught by spin-fishing were injured more frequently than fish caught by fly-fishing. Fewer fly-fishing-caught fish were injured using circle hooks, and circle hooks tended to hook fish in only one location, generally in the jaw. Barbed J hooks were more efficient at landing fish, and J hooks were more efficient at landing fish than circle hooks. Novice anglers injured proportionally more fish than experienced anglers, primarily during hook removal. Landing time was positively correlated with fish size, and experienced anglers took longer to land fish than novices because they captured larger fish. These results suggest that a reduction in hooking injuries may be achieved by using circle hooks as an alternative to J hooks and barbless J hooks to reduce injury and handling time, yet catch efficiency for both methods would be reduced. Although fish captured with barbless J hooks and circle hooks had fewer injuries, it is important to note that each hook type also caused significant injury, and angler education is recommended to promote proper hook removal techniques.

  17. VOLATILE OIL COMPOSITION OF THE LEAVES OF EUCALYPTUS CITRIODORA HOOK.

    Directory of Open Access Journals (Sweden)

    Mittal Abhilasha

    2011-02-01

    Full Text Available The leaves of Eucalyptus citriodora Hook. (Myrtaceae of Delhi region yielded 0.22 % of the volatile oil which was analyzed by GC and GC-MS techniques. Fifteen components comprising 100 % of the total volatiles were identified which consisted of five monoterpenes (96.3 % and ten aliphatic components (3.7 %. The major monoterpenes characterized included α- pinene (38.6 %, β -.pinene (25.7%, sabinene (19.6% and α-thujene (11.9%. Among the aliphatic constituents, there were six hydrocarbons (2.3 % and four aliphatic alcohols (1.4 %. Myrcene and all aliphatic constituents were present in trace amounts.

  18. VOLATILE OIL COMPOSITION OF THE LEAVES OF EUCALYPTUS CITRIODORA HOOK.

    OpenAIRE

    Mittal Abhilasha; Ali Mohammed

    2011-01-01

    The leaves of Eucalyptus citriodora Hook. (Myrtaceae) of Delhi region yielded 0.22 % of the volatile oil which was analyzed by GC and GC-MS techniques. Fifteen components comprising 100 % of the total volatiles were identified which consisted of five monoterpenes (96.3 %) and ten aliphatic components (3.7 %). The major monoterpenes characterized included α- pinene (38.6 %), β -.pinene (25.7%), sabinene (19.6%) and α-thujene (11.9%). Among the aliphatic constituents, there were six hydrocarbo...

  19. The Star Formation Camera

    OpenAIRE

    Scowen, Paul A.; Jansen, Rolf; Beasley, Matthew; Calzetti, Daniela; Desch, Steven; Fullerton, Alex; Gallagher, John; Lisman, Doug; Macenka, Steve; Malhotra, Sangeeta; McCaughrean, Mark; Nikzad, Shouleh; O'Connell, Robert; Oey, Sally; Padgett, Deborah

    2009-01-01

    The Star Formation Camera (SFC) is a wide-field (~15'x19, >280 arcmin^2), high-resolution (18x18 mas pixels) UV/optical dichroic camera designed for the Theia 4-m space-borne space telescope concept. SFC will deliver diffraction-limited images at lambda > 300 nm in both a blue (190-517nm) and a red (517-1075nm) channel simultaneously. Our aim is to conduct a comprehensive and systematic study of the astrophysical processes and environments relevant for the births and life cycles of stars and ...

  20. 75 FR 4265 - Airworthiness Directives; Lifesavings Systems Corp., D-Lok Hook Assembly

    Science.gov (United States)

    2010-01-27

    ... 12866; 2. Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034... Corp., D-Lok Hook Assembly AGENCY: Federal Aviation Administration (FAA), Department of Transportation... (AD) for the Lifesavings Systems Corp., D-Lok Hook assembly installed on certain rescue...

  1. A Novel Diterpenoid,11-O-β-D-glucopyranosylneo-triptophenolide, from Tripterygium wilfordii Hook. f

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new diterpenoid was isolated from the ethanolic extract of the dried root bark of Tripterygium wilfordii Hook.f. It is the first example of abietane diterpenoid glycoside isolated from Tripterygium wilfordii Hook.f. Its structure was identified to be 11-O-β-D-glucopyranosyl neotriptophenolide based on spectral methods.

  2. Does Subacromial Osteolysis Affect Shoulder Function after Clavicle Hook Plating?

    Science.gov (United States)

    Sun, Siwei; Gan, Minfeng; Sun, Han; Wu, Guizhong; Yang, Huilin; Zhou, Feng

    2016-01-01

    Purpose. To evaluate whether subacromial osteolysis, one of the major complications of the clavicle hook plate procedure, affects shoulder function. Methods. We had performed a retrospective study of 72 patients diagnosed with a Neer II lateral clavicle fracture or Degree-III acromioclavicular joint dislocation in our hospital from July 2012 to December 2013. All these patients had undergone surgery with clavicle hook plate and were divided into two groups based on the occurrence of subacromial osteolysis. By using the Constant-Murley at the first follow-up visit after plates removal, we evaluated patients' shoulder function to judge if it has been affected by subacromial osteolysis. Results. We have analyzed clinical data for these 72 patients, which shows that there is no significant difference between group A (39 patients) and group B (33 patients) in age, gender, injury types or side, and shoulder function (the Constant-Murley scores are 93.38 ± 3.56 versus 94.24 ± 3.60, P > 0.05). Conclusion. The occurrence of subacromial osteolysis is not rare, and also it does not significantly affect shoulder function. PMID:27034937

  3. Capsular hook-assisted implantation of modified capsular tension ring.

    Science.gov (United States)

    Khokhar, Sudarshan; Gupta, Shikha; Nayak, Bhagabat; Gogia, Varun

    2016-01-01

    A 16-year-old boy presented with decrease of vision over a period of 2 years. On examination, he was diagnosed to have microspherophakia with lenticular myopia with secondary glaucoma in both eyes. He was treated by lens aspiration and two-point capsular support using a modified capsular tension ring (M-CTR) and capsular tension segment (CTS) sutured to the sclera along with implantation of a foldable intraocular lens inside the bag. Lens aspiration was performed without artificial capsular hook support of the bag, as the lens was soft and vitreous was formed. However, M-CTR rotation into the bag was fraught with repeated adherence of the advancing end of the M-CTR into the loose bag causing simultaneous rotation of the bag with the rotation of the ring resulting in transient increase in bag subluxation. Capsular hooks provided appropriate countertraction to the unsupported bag, thus facilitating easy insertion and rotation of the ring into the bag. PMID:27048263

  4. Hooking tomorrow's geoscientists: Authentic field inquiry as a compelling pedagogy

    Science.gov (United States)

    Wallstrom, Erica

    2015-04-01

    Engaging high school students in the geosciences without providing them with opportunities to directly explore, understand, and question the natural world is like trying to catch a fish without a hook. How can educators hope to inspire youth to pursue a career in the geosciences when the subject is first introduced to teenagers within the confines of a classroom? Regardless of the content and activities employed by the teacher, the synthetic classroom setting is unable to recreate the organic richness of an authentic outdoor learning environment. A new course offering at Rutland High School in Rutland, Vermont, USA shifts away from the traditional classroom based pedagogy by focusing the learning on exploring the temporal changes occurring in the region's geologic features. Numerous visits to local quarries, outcrops, overlooks, and universities guide the course curriculum. Students use their new understandings and personal observations to complete a culminating independent investigation. This alternate learning model is made possible through collaboration with local universities, businesses, and government agencies. If the geosciences is to remain competitive in the recruitment of exemplary STEM candidates, than the focus of high school earth science programs must be considered. This course offers one alternative to improve engagement and understanding of the geoscience standards. While not the only option, it offers one possibility for hooking students on geosciences.

  5. The Hook: Getting your grounded theory research published

    Directory of Open Access Journals (Sweden)

    Phyllis Noerager Stern, DNS, LLD (hon., FAAN

    2009-01-01

    Full Text Available I learned about the hook as a fledgling writer back in the late 70’s, and early 80s. I wrote about stepfamilies when almost nobody else did (Stern, 1978, 1982a, 1982b. My big break came when I published an English-language version on how to do grounded theory. In my field, nursing, grounded theory was the buzz word of the day, but few nurses had a sociological background, and thus the vocabulary to be able to understand the Glaser and Straus description (Stern, 1980. That article kick started my career as a writer and researcher. There was a time when it was required reading for graduate students in nursing around the world. Twenty-nine years after its publication, I got a request for a reprint from a doctoral student in New Zealand. What the hook consists of then is timing, a subject that has impact, and a title that sparks the interest of a potential reader. A classic example of all three is The Discovery of Grounded Theory (Glaser and Straus, 1967, a then new approach to sociological research. Sociologists were interested, but as the authors were based at the University of California, San Francisco School of Nursing, they had an eager audience in the nursing community who were looking for a research method to formalize what they did as nurses.

  6. Does Subacromial Osteolysis Affect Shoulder Function after Clavicle Hook Plating?

    Directory of Open Access Journals (Sweden)

    Siwei Sun

    2016-01-01

    Full Text Available Purpose. To evaluate whether subacromial osteolysis, one of the major complications of the clavicle hook plate procedure, affects shoulder function. Methods. We had performed a retrospective study of 72 patients diagnosed with a Neer II lateral clavicle fracture or Degree-III acromioclavicular joint dislocation in our hospital from July 2012 to December 2013. All these patients had undergone surgery with clavicle hook plate and were divided into two groups based on the occurrence of subacromial osteolysis. By using the Constant-Murley at the first follow-up visit after plates removal, we evaluated patients’ shoulder function to judge if it has been affected by subacromial osteolysis. Results. We have analyzed clinical data for these 72 patients, which shows that there is no significant difference between group A (39 patients and group B (33 patients in age, gender, injury types or side, and shoulder function (the Constant-Murley scores are 93.38±3.56 versus 94.24±3.60, P>0.05. Conclusion. The occurrence of subacromial osteolysis is not rare, and also it does not significantly affect shoulder function.

  7. A novel approach for removing the hook effect artefact from Electrical Bioimpedance spectroscopy measurements

    Science.gov (United States)

    Buendia, R.; Seoane, F.; Gil-Pita, R.

    2010-04-01

    Very often in Electrical Bioimpedance (EBI) spectroscopy measurements the presence of stray capacitances creates a measurement artefact commonly known as Hook Effect. Such an artefact creates a hook-alike deviation of the EBI data noticeable when representing the measurement on the impedance plane. Such Hook Effect is noticeable at high frequencies but it also causes a data deviation at lower measurement frequencies. In order to perform any accurate analysis of the EBI spectroscopy data, the influence of the Hook Effect must be removed. An established method to compensate the hook effect is the well known Td compensation, which consists on multiplying the obtained spectrum, Zmeas(ω) by a complex exponential in the form of exp[jωTd]. Such a method cannot correct entirely the Hook Effect since the hook-alike deviation occurs a broad frequency range in both magnitude and phase of the measured impedance, and by using a scalar value for Td. First a scalar only modifies the phase of the measured impedance and second, a single value can truly corrects the Hook Effect only at a single frequency. In addition, the process to select a value for the scalar Td by an iterative process with the aim to obtain the best Cole fitting lacks solid scientific grounds. In this work the Td compensation method is revisited and a modified approach for correcting the Hook Effect including a novel method for selecting the correcting values is proposed. The initial validation results confirm that the proposed method entirely corrects the Hook Effect at all frequencies.

  8. Sesquiterpenoids of Senecio bonariensis Hook. & Arn., Asteraceae Sesquiterpenóides de Senecio bonariensis Hook. & Arn., Asteraceae

    Directory of Open Access Journals (Sweden)

    Chana de Medeiros da Silva

    2010-03-01

    Full Text Available From the leaves of Senecio bonariensis Hook. & Arn. three sesquiterpenoids were isolated. β-caryophyllene (1, β-caryophyllene oxide (2 and germacrene D (3 were characterized by GC-EI-MS, IR, ¹H and 13C-NMR data. Their ecological and chemotaxonomical significance for the genus Senecio are discussed, as well as the biosynthetic correlation between the isolated substances. The antimicrobial activity of substances 1 and 2 were evaluated by the microdilution method against bacterial and fungal strains. Both compounds did not inhibit the microorganism growth at the tested concentrations.Das folhas de Senecio bonariensis Hook. & Arn. foram isolados três sesquiterpenóides. β-Cariofileno (1, óxido de β-cariofileno (2 e germacreno D (3 foram identificados por CG-IE-EM, IV, ¹H and 13C-RMN. A importância ecológica e quimiotaxionômica para o gênero Senecio é discutida, assim como a correlação biossintética entre as substâncias isoladas. As substâncias 1 e 2 tiveram sua atividade antimicrobiana avaliada pelo método de microdiluição em caldo contra cepas bacterianas e fúngicas. Ambas não inibiram o crescimento microbiano nas concentrações testadas.

  9. Blue and White Pot

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    Many recent archaeological studies have proven that the earliest blue and white porcelain was produced from the kiln in Gongxian County, Henan Province in the Tang Dynasty (618-907). It was an important variety of porcelain available for export then. The early blue and white porcelain in the Yuan Dynasty appeared dark and gray. During the reign of Zhizheng, clear blue and white porcelain was produced, indicating

  10. DETECTION OF WHITE DWARF COMPANIONS TO BLUE STRAGGLERS IN THE OPEN CLUSTER NGC 188: DIRECT EVIDENCE FOR RECENT MASS TRANSFER

    Energy Technology Data Exchange (ETDEWEB)

    Gosnell, Natalie M.; Mathieu, Robert D. [Department of Astronomy, University of Wisconsin - Madison, 475 N. Charter St., Madison, WI 53706 (United States); Geller, Aaron M. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208 (United States); Sills, Alison [Department of Physics and Astronomy, McMaster University, 1280 Main St. W, Hamilton, ON L8S 4M1 (Canada); Leigh, Nathan [Department of Physics, University of Alberta, CCIS 4-183, Edmonton, AB T6G 2E1 (Canada); Knigge, Christian, E-mail: gosnell@astro.wisc.edu [School of Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 IBJ (United Kingdom)

    2014-03-01

    Several possible formation pathways for blue straggler stars have been developed recently, but no one pathway has yet been observationally confirmed for a specific blue straggler. Here we report the first findings from a Hubble Space Telescope Advanced Camera for Surveys/Solar Blind Channel far-UV photometric program to search for white dwarf companions to blue straggler stars. We find three hot and young white dwarf companions to blue straggler stars in the 7 Gyr open cluster NGC 188, indicating that mass transfer in these systems ended less than 300 Myr ago. These companions are direct and secure observational evidence that these blue straggler stars were formed through mass transfer in binary stars. Their existence in a well-studied cluster environment allows for observational constraints of both the current binary system and the progenitor binary system, mapping the entire mass transfer history.

  11. Feeling blue? Blue phosphors for OLEDs

    Directory of Open Access Journals (Sweden)

    Hungshin Fu

    2011-10-01

    Full Text Available Research on organic light emitting diodes (OLEDs has been revitalized, partly due to the debut of the OLED TV by SONY in 2008. While there is still plenty of room for improvement in efficiency, cost-effectiveness and longevity, it is timely to report on the advances of light emitting materials, the core of OLEDs, and their future perspectives. The focus of this account is primarily to chronicle the blue phosphors developed in our laboratory. Special attention is paid to the design strategy, synthetic novelty, and their OLED performance. The report also underscores the importance of the interplay between chemistry and photophysics en route to true-blue phosphors.

  12. Efficiency of voluntary opening hand and hook prosthetic devices: 24 years of development?

    Directory of Open Access Journals (Sweden)

    Gerwin Smit, MSc

    2012-06-01

    Full Text Available Quantitative data on the mechanical performance of upper-limb prostheses are very important in prostheses development and selection. The primary goal of this study was to objectively evaluate the mechanical performance of adult-size voluntary opening (VO prosthetic terminal devices and select the best tested device. A second goal was to see whether VO devices have improved in the last two decades. Nine devices (four hooks and five hands were quantitatively tested (Hosmer model 5XA hook, Hosmer Sierra 2 Load VO hook, RSL Steeper Carbon Gripper, Otto Bock model 10A60 hook, Becker Imperial hand, Hosmer Sierra VO hand, Hosmer Soft VO hand, RSL Steeper VO hand, Otto Bock VO hand. We measured the pinch forces, activation forces, cable displacements, mass, and opening span and calculated the work and hysteresis. We compared the results with data from 1987. Hooks required lower activation forces and delivered higher pinch forces than hands. The activation forces of several devices were very high. The pinch forces of all tested hands were too low. The Hosmer model 5XA hook with three bands was the best tested hook. The Hosmer Sierra VO hand was the best tested hand. We found no improvements in VO devices compared with the data from 1987.

  13. Cryopreservation of Galanthus elwesii Hook. apical meristems by droplet vitrification.

    Science.gov (United States)

    Maslanka, M; Panis, B; Bach, A

    2013-01-01

    The aim of this study was to develop an efficient cryopreservation protocol for the geophyte giant snowdrop (Galanthus elwesii Hook.) that guarantees a high rate of survival and plant regeneration after cryopreservation. The excised apical meristems were obtained from cultures of in vitro grown bulb scales. Using a vitrification procedure and optimizing the duration of the exposure to the loading solution (LS), meristem post-rewarm survival rates higher than 90 percent were achieved. Also regrowth percentages were very high, ranging from 87 to 91 percent. After optimizing the time of exposure to the plant vitrification solution (PVS2), the survival rate was between 83 and 97 percent. During post-rewarm regeneration, good growth recovery was as high as 76 percent; however, hyperhydration and callusing were also observed. The results demonstrate that cryopreservation of Galanthus elwesii germplasm seems to be feasible. PMID:23435704

  14. New steroidal saponin from Antigonon leptopus Hook. and Arn.

    Directory of Open Access Journals (Sweden)

    Maria Karmella L Apaya

    2014-01-01

    Full Text Available Background: Antigonon leptopus Hook. and Arn., Polygonaceae (cadena de amor, is a herbal remedy for pain and gout-like symptoms in the Philippines. The methanol extract of A. leptopus have shown strong inhibitory action against xanthine oxidase. Objective: To isolate and identify the compound responsible for the xanthine oxidase inhibitory action. Materials and Methods: A bioassay-guided isolation scheme using an in vitro assay for the inhibition of xanthine oxidase was employed. The structure was established using spectroscopic analysis and chemical methods. Results: The isolated compound was determined to be a noncompetitive inhibitor of xanthine with an IC50 of 1.79 μg/mL. Conclusion: The isolated compound may represent a new class of xanthine oxidase inhibitors.

  15. Cryopreservation of Galanthus elwesii Hook. apical meristems by droplet vitrification.

    Science.gov (United States)

    Maslanka, M; Panis, B; Bach, A

    2013-01-01

    The aim of this study was to develop an efficient cryopreservation protocol for the geophyte giant snowdrop (Galanthus elwesii Hook.) that guarantees a high rate of survival and plant regeneration after cryopreservation. The excised apical meristems were obtained from cultures of in vitro grown bulb scales. Using a vitrification procedure and optimizing the duration of the exposure to the loading solution (LS), meristem post-rewarm survival rates higher than 90 percent were achieved. Also regrowth percentages were very high, ranging from 87 to 91 percent. After optimizing the time of exposure to the plant vitrification solution (PVS2), the survival rate was between 83 and 97 percent. During post-rewarm regeneration, good growth recovery was as high as 76 percent; however, hyperhydration and callusing were also observed. The results demonstrate that cryopreservation of Galanthus elwesii germplasm seems to be feasible.

  16. Ultrastructure and oil secretion in Hiptage sericea Hook

    Directory of Open Access Journals (Sweden)

    K. Arumugasamy

    2014-02-01

    Full Text Available The oil secreting glands of Hiptage sericea Hook. consist of three regions: epithelial, sub-epithelial and sub-glandular. In early stages, the oil secreting cells are characterized by the presence of plastids with starch grains and electron translucent vesicles, mitochondria, rER, polysomes, small vacuoles, numerous lipid bodies and well-defined nucleus with nucleolus. Later, the accumulation of plastoglobuli and inclusion bodies occur in the matrix of the plastid. Tubular, smooth endoplasmic reticulum begins to appear in the cytoplasm. With the onset of secretion, the osmiophilic contents of plastids which appear as electron dense, round droplets move-into cytoplasm and often occur in the region of the plasmalemma invaginations. However, in matured glands the lipid bodies disappear from the cytoplasm. The size of the vacuoles increases and are filled with electron opaque substance. Similar substances are also found in the sub-cuticular spaces as well as outside the cuticle.

  17. Coordinated regulation of apical hook development by gibberellins and ethylene in etiolated Arabidopsis seedlings

    Institute of Scientific and Technical Information of China (English)

    Fengying An; Xing Zhang; Ziqiang Zhu; Yusi Ji; Wenrong He; Zhiqiang Jiang; Mingzhe Li; Hongwei Guo

    2012-01-01

    Dark-grown Arabidopsis seedlings develop an apical hook when germinating in soil,which protects the cotyledons and apical meristematic tissues when protruding through the soil.Several hormones are reported to distinctly modulate this process.Previous studies have shown that ethylene and gibberellins (GAs) coordinately regulate the hook development,although the underlying molecular mechanism is largely unknown.Here we showed that GA3 enhanced while paclobutrazol repressed ethylene- and EIN3-overexpression (EIN3ox)-induced hook curvature,and della mutant exhibited exaggerated hook curvature,which required an intact ethylene signaling pathway.Genetic study revealed that GA-enhanced hook development was dependent on HOOKLESS 1 (HLS1),a central regulator mediating the input of the multiple signaling pathways during apical hook development.We further found that GA3 induced (and DELLA proteins repressed) HLS1 expression in an ETHYLENE INSENSITIVE 3/EIN3-LIKE 1 (EIN3/EIL1)-dependent manner,whereby EIN3/EIL1 activated HLS1 transcription by directly binding to its promoter.Additionally,DELLA proteins were found to interact with the DNA-binding domains of EIN3/EIL1 and repress EIN3/EIL1-regulated HLS1 expression.Treatment with naphthylphthalamic acid,a polar auxin transport inhibitor,repressed the constitutively exaggerated hook curvature of EIN3ox line and della mutant,supporting that auxin functions downstream of the ethylene and GA pathways in hook development.Taken together,our results identify EIN3/EIL1 as a new class of DELLA-associated transcription factors and demonstrate that GA promotes apical hook formation in cooperation with ethylene partly by inducing the expression of HLS1 via derepression of EIN3/EIL1 functions.

  18. Blue Willow Story Plates

    Science.gov (United States)

    Fontes, Kris

    2009-01-01

    In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made.

  19. From blue jeans to blue genes.

    Science.gov (United States)

    Boon, Laurence M; Vikkula, Miikka

    2009-03-01

    Cutaneous venous anomalies are common. They are blue and vary in size, number, and location and account for most consultations at specialized interdisciplinary clinics for vascular anomalies. Venous lesions are clinically important because they cause pain, dysfunction, destruction of adjacent tissues, and esthetic concern. Only resection and sclerotherapy are helpful, although not always curative. Understanding etiopathogenesis could help design animal models and develop novel therapeutic approaches. John B. Mulliken, MD, envisioned a project to uncover the genetic basis of an inherited form of venous malformation in a large New England family. Recruitment of 2 young fellows resulted in a collaborative project that unraveled the searched-for gene and its mutation. This was an opening for a new era in vascular anomalies. Two blue genes' mutations were discovered, which account for most, if not all, of the inherited forms of venous anomalies, but other genes as well, for rheologically diverse lesions. Differential diagnosis and management has improved, and animal models are being made. This was achieved through the help of Dr Mulliken, who inspired 2 young investigators in blue jeans to find 2 blue genes.

  20. Blue ocean strategy.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2004-10-01

    Despite a long-term decline in the circus industry, Cirque du Soleil profitably increased revenue 22-fold over the last ten years by reinventing the circus. Rather than competing within the confines of the existing industry or trying to steal customers from rivals, Cirque developed uncontested market space that made the competition irrelevant. Cirque created what the authors call a blue ocean, a previously unknown market space. In blue oceans, demand is created rather than fought over. There is ample opportunity for growth that is both profitable and rapid. In red oceans--that is, in all the industries already existing--companies compete by grabbing for a greater share of limited demand. As the market space gets more crowded, prospects for profits and growth decline. Products turn into commodities, and increasing competition turns the water bloody. There are two ways to create blue oceans. One is to launch completely new industries, as eBay did with online auctions. But it's much more common for a blue ocean to be created from within a red ocean when a company expands the boundaries of an existing industry. In studying more than 150 blue ocean creations in over 30 industries, the authors observed that the traditional units of strategic analysis--company and industry--are of limited use in explaining how and why blue oceans are created. The most appropriate unit of analysis is the strategic move, the set of managerial actions and decisions involved in making a major market-creating business offering. Creating blue oceans builds brands. So powerful is blue ocean strategy, in fact, that a blue ocean strategic move can create brand equity that lasts for decades. PMID:15559577

  1. Blue ocean strategy.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2004-10-01

    Despite a long-term decline in the circus industry, Cirque du Soleil profitably increased revenue 22-fold over the last ten years by reinventing the circus. Rather than competing within the confines of the existing industry or trying to steal customers from rivals, Cirque developed uncontested market space that made the competition irrelevant. Cirque created what the authors call a blue ocean, a previously unknown market space. In blue oceans, demand is created rather than fought over. There is ample opportunity for growth that is both profitable and rapid. In red oceans--that is, in all the industries already existing--companies compete by grabbing for a greater share of limited demand. As the market space gets more crowded, prospects for profits and growth decline. Products turn into commodities, and increasing competition turns the water bloody. There are two ways to create blue oceans. One is to launch completely new industries, as eBay did with online auctions. But it's much more common for a blue ocean to be created from within a red ocean when a company expands the boundaries of an existing industry. In studying more than 150 blue ocean creations in over 30 industries, the authors observed that the traditional units of strategic analysis--company and industry--are of limited use in explaining how and why blue oceans are created. The most appropriate unit of analysis is the strategic move, the set of managerial actions and decisions involved in making a major market-creating business offering. Creating blue oceans builds brands. So powerful is blue ocean strategy, in fact, that a blue ocean strategic move can create brand equity that lasts for decades.

  2. 2011 Delaware Department of Natural Resources and Environmental Control (DNREC) Lidar: Bombay Hook National Wildlife Refuge

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Terrapoint collected LiDAR for over 177 square kilometers of the Bombay Hook National Wildlife Refuge in Kent County, Delaware. The nominal pulse spacing for this...

  3. Response of Greater Snow Geese to Hunting at Bombay Hook NWR and Related Wetland Changes.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Wintering snow goose populations have increased dramatically in the vicinity of Bombay Hook National Wildlife Refuge during the last 20 years. Peak populations have...

  4. Annual Water Management Program Report Prime Hook National Wildlife Refuge 1995

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report describes the results of Prime Hook's 1994 Water Management. Program and delineates plans for 1995. 1994 marked the third year that asynchronous...

  5. Annual Water Management Program Report Prime Hook National Wildlife Refuge 1998

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The main goal of Prime Hook's water management program is to increase the carrying capacity of the refuge's marshes by maximizing the annual production of diverse...

  6. Prime Hook National Wildlife Refuge Annual narrative report: Calendar year 1979

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Prime Hook National Wildlife Refuge outlines Refuge accomplishments during the 1979 calendar year. The report begins with an introduction...

  7. Effects of Proposed Water Control Structure at Prime Hook National Wildlife Refuge 1981

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The United States Fish and Wildlife Service is studying the feasibility of constructing a water control structure on the Prime Hook National Wildlife Refuge. The...

  8. Annual Hunting Program for Prime Hook National Wildlife Refuge 1987-88

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report outlines the results of the 198687 hunting season and lays out estimates for the 198788 season at Prime Hook National Wildlife Refuge. It details the...

  9. Assessment of Fishery Resources at Prime Hook National Wildlife Refuge 1994

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Baseline information on the abundance, distribution and species diversity of fishes and general water quality parameters at the Prime Hook National Wildlife Refuge...

  10. Fire Management Plan for Prime Hook National Wildlife Refuge Fiscal Year 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — If habitat conditions permit, prescribed burning will be used for management in eight areas totaling 1685 acres at Prime Hook National Wildlife Refuge in the fiscal...

  11. Prime Hook National Wildlife Refuge : Annual narrative report : Calendar year 1985

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Prime Hook National Wildlife Refuge outlines Refuge accomplishments during the 1985 calendar year. The report begins with a summary...

  12. COMPARATIVE ANALYSIS OF AUTOGRAFT TECHNIQUE AND CLAVICULAR HOOK PLATE IN GRADE 3 ACROMIOCLAVICULAR DISLOCATIONS

    Directory of Open Access Journals (Sweden)

    Rahul Narayan

    2016-04-01

    Full Text Available OBJECTIVE To evaluate clinical outcome of clavicular hook plate and autograft technique in the surgical treatment of Rockwood Grade-III acromioclavicular joint dislocation. METHODS Fifteen patients were operated using standard clavicular hook plate and another fifteen patients were operated using autograft technique. After a minimum follow-up of one year, clinical assessment was done using Constant-Murley Score. Statistical evaluation was done using SPSS ver. 21.0. RESULTS Mean age group was 31.44±7.8 years. Average constant shoulder score for the hook plate group was 81.3 (Range 74–89 and that for autograft technique group was 91.7 (Range 88–97. CONCLUSION Autograft technique was found to be superior in terms of functional outcome when compared to clavicular hook plate. Such superiority can be attributed to the biologic nature of coracoclavicular ligament reconstruction in the autograft technique.

  13. Visitor and community survey results for Prime Hook National Wildlife Refuge : Completion report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report provides a summary of results for the community and visitor surveys conducted at Prime Hook NWR from the fall of 2004 through fall of 2005. The purpose...

  14. Summary of recreational hook and line caught sea turtles documented by the NOAA Galveston Laboratory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The database is a summary of sea turtles that are hook and line captured by recreational anglers in the region covered by the NOAA Galveston Laboratory through its...

  15. Annual Water Management Program Report Prime Hook National Wildlife Refuge 1994

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This program describes the results of the marsh and water level management actions of Prime Hook National Wildlife Refuge in 1993 and outlines the planned...

  16. Cultural Resources Survey for Additional Work at Prime Hook National Wildlife Refuge 1981

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A cultural resources survey was conducted at Prime Hook National Wildlife Refuge, Sussex County, during the late summer of 1981. This work concentrated on the...

  17. Annual Marsh and Water Management Program Report Prime Hook National Wildlife Refuge 2000

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This program describes the results of the marsh and water level management actions of Prime Hook National Wildlife Refuge in 1999 and outlines the planned...

  18. Annual Water Management Program Report Prime Hook National Wildlife Refuge 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report outlines current and past water management efforts at Prime Hook National Wildlife Refuge. It starts with the history of water management, including the...

  19. Environmental Assessment Rehabilitation and Maintenance of Wetlands Unit 3 Prime Hook National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — For management purposes, Prime Hook is divided into four units using highways which transect the refuge. This proposal concerns the rehabilitation of wetlands...

  20. Annual Water Management Program Report Prime Hook National Wildlife Refuge 1991

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report outlines current and past water management efforts at Prime Hook National Wildlife Refuge. It starts with the history of water management, including the...

  1. Environmental Assessment for the Reestablishment of Water Control Unit 2: Prime Hook National Wildlife Refuge: 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — An environmental assessment for reestablishment of water control in Unit II of the Prime Hook National Wildlife Refuge was prepared in November, 1985. The Fish and...

  2. Annual Water Management Program Report Prime Hook National Wildlife Refuge 1992

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report outlines current and past water management efforts at Prime Hook National Wildlife Refuge. It starts with the history of water management, including the...

  3. Comprehensive Conservation Plan for Prime Hook National Wildlife Refuge March 2013

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) was written to guide management on Prime Hook National Wildlife Refuge for the next 15 years. This plan outlines the...

  4. Annual Water Management Program Report Prime Hook National Wildlife Refuge 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report outlines current and past water management efforts at Prime Hook National Wildlife Refuge. It starts with the history of water management, including the...

  5. Advance of the Research on Tripterygium wilfordii Hook f. to A New Height

    Institute of Scientific and Technical Information of China (English)

    QIN Wan-zhang; LIN Jian

    2005-01-01

    @@ Tripterygium wilfordii Hook f. (TW) has long been a treasure among Chinese traditional herbs. As a prospective drug, it has been used widely in recent 20 years, and has aroused extensive attention at home and abroad.

  6. Annual Water Management Program Report Prime Hook National Wildlife Refuge 1988

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Approximately 77% of Prime Hook National Wildlife Refuge’s 8818 acres consists of wetlands types, both salt and fresh marsh, and brackish and fresh water. Water...

  7. Annual Water Management Program Report Prime Hook National Wildlife Refuge 1997

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the results of Prime Hook National Wildlife Refuge’s 1996 annual water management program and describes plans for 1997. The main objective of...

  8. Annual Marsh and Water Management Program Report Prime Hook National Wildlife Refuge 2003

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report describes the results of the 2002 marsh and water level management actions and summarizes the planned strategies for calendar year 2003 at Prime Hook...

  9. Prime Hook National Wildlife Refuge : Annual narrative report : Calendar year 1995

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Prime Hook National Wildlife Refuge outlines Refuge accomplishments during the 1995 calendar year. The report begins with a summary...

  10. Annual Water Management Program Report Prime Hook National Wildlife Refuge 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Approximately 77% of Prime Hook National Wildlife Refuge’s 8818 acres consists of wetlands types, both salt and fresh marsh, and brackish and fresh water. Water...

  11. Cropland and Grassland Management Plan Prime Hook National Wildlife Refuge 1987

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A major wildlife objective for the Prime Hook National Wildlife Refuge is the production of food for Canada geese during the fall migration, winter and spring...

  12. Environmental Assessment for the Establishment of a Trapping Program at Prime Hook National Wildlife Refuge 1987

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Prior to ownership of the Prime Hook marshes by the Fish and Wildlife Service, records show as many as 25,000 muskrats were harvested annually. Deterioration of the...

  13. 76 FR 26751 - Prime Hook National Wildlife Refuge, Sussex County, DE; Comprehensive Conservation Plan and...

    Science.gov (United States)

    2011-05-09

    ... the planting of genetically modified organisms until the refuge completed compatibility determinations... 17, 2005 (70 FR 60365) stating we intended to prepare a CCP and EA for Prime Hook NWR. We held...

  14. Development and impact of hooks of high droplet concentration on remote southeast Pacific stratocumulus

    Directory of Open Access Journals (Sweden)

    R. C. George

    2013-07-01

    Full Text Available Over the southeastern Pacific (SEP, droplet concentration (Nd in the typically unpolluted marine stratocumulus west of 80° W (> 1000 km offshore is periodically strongly enhanced in zonally elongated "hook"-shaped features that increase albedo. Here, we examine three hook events using the chemistry version of the Weather Research and Forecasting model (WRF-Chem with 14 km horizontal resolution, satellite data, and aircraft data from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx. A particularly strong hook yields insights into the development, decay, and radiative impact of these features. Hook development occurs with Nd increasing to polluted levels over the remote ocean primarily due to entrainment of cloud condensation nuclei (CCN from the lower free troposphere (FT. The feature advects northwestward until the FT CCN source is depleted, after which Nd decreases over a few days due to precipitation and dilution. The model suggests that the FT CCN source supplying the hook consists of high concentrations of small accumulation-mode aerosols that contribute a relatively small amount of aerosol mass to the MBL, in agreement with near-coast VOCALS measurements of polluted layers in the FT. The aerosol particles in this hook originate mainly from a pulse of offshore flow that transports Santiago-region (33–35° S emissions to the remote marine FT. To provide pollution CCN that can sustain hooks, the FT transport of pollution plumes to the remote ocean requires strong, deep offshore flow. Such flow is favored by a trough approaching the South American coast and a southeastward shift of the climatological subtropical high-pressure system. The model simulations show precipitation suppression in the hook and a corresponding increase in liquid water path (LWP compared with a simulation without anthropogenic sources. LWP also increases as the hook evolves over time due to increasing stability and decreasing subsidence. WRF

  15. Comprehensive Plan to Resolve Resource Problems at Prime Hook National Wildlife Refuge 1984

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In October of 1981, Prime Hook National Wildlife Refuge completed a questionnaire that helped to define possible threats and conflicts to the refuge. Through this...

  16. By Hook or by Crook? Morphometry, Competition and Cooperation in Rodent Sperm

    OpenAIRE

    Simone Immler; Harry D M Moore; Breed, William G.; Tim R Birkhead

    2007-01-01

    Background Sperm design varies enormously across species and sperm competition is thought to be a major factor influencing this variation. However, the functional significance of many sperm traits is still poorly understood. The sperm of most murid rodents are characterised by an apical hook of the sperm head that varies markedly in extent across species. In the European woodmouse Apodemus sylvaticus (Muridae), the highly reflected apical hook of sperm is used to form sperm groups, or “tr...

  17. COMPARATIVE ANALYSIS OF AUTOGRAFT TECHNIQUE AND CLAVICULAR HOOK PLATE IN GRADE 3 ACROMIOCLAVICULAR DISLOCATIONS

    OpenAIRE

    Rahul Narayan; Ojas

    2016-01-01

    OBJECTIVE To evaluate clinical outcome of clavicular hook plate and autograft technique in the surgical treatment of Rockwood Grade-III acromioclavicular joint dislocation. METHODS Fifteen patients were operated using standard clavicular hook plate and another fifteen patients were operated using autograft technique. After a minimum follow-up of one year, clinical assessment was done using Constant-Murley Score. Statistical evaluation was done using SPSS ver. 21.0. RES...

  18. Efficiency of voluntary opening hand and hook prosthetic devices: 24 years of development?

    OpenAIRE

    Gerwin Smit, MSc; Raoul M. Bongers, MSc, PhD; Corry K. van der Sluis, MD, PhD; Dick H. Plettenburg, MSc, PhD

    2012-01-01

    Quantitative data on the mechanical performance of upper-limb prostheses are very important in prostheses development and selection. The primary goal of this study was to objectively evaluate the mechanical performance of adult-size voluntary opening (VO) prosthetic terminal devices and select the best tested device. A second goal was to see whether VO devices have improved in the last two decades. Nine devices (four hooks and five hands) were quantitatively tested (Hosmer model 5XA hook, Hos...

  19. Structural study and geochronology in the Hook Batholith, Central Zambia

    Science.gov (United States)

    Naydenov, K.; Lehmann, J.; Saalmann, K.; Milani, L.; Kinnaird, J.; Charlesworth, G.; Frei, D.

    2013-12-01

    The Pan-African Hook batholith is emplaced N of the Mwembeshi dislocation, a regional scale structure at the contact between Zambezi Belt and Lufilian Arc in Central Zambia. Exposed over 12000 km2 the batholith is composed mainly of fine-grained and coarse-grained porphyritic granites and leucogranites affected by solid-state deformation along high-strain zones. Two main zones of deformation were investigated - the Itezhi-Tezhi Zone (ITZ) in the SW part of the batholith and the Nalusanga Zone (NZ) to the NE. The 2.5 km wide, N-S trending, subvertical ITZ is a medium-grade, pure shear dominated structure, reflecting probably regional scale E-W shortening. In the central part of the zone, augen-gneiss textures developed. Mineral lineations plunging ~40° S are recorded occasionally. The deformed feldspar porphyroclasts show symmetrical tails and rarely sinistral stair-stepping. In the SE part of the Hook batholith the continuation of the ITZ trends E-W. This orientation can be explained by rotation of the original ITZ trend by N-S shortening that also has been recorded in the siliciclastic metasediments S of the contact. S dipping, up to 15 cm wide thrust zones observed in the ITZ area were probably formed during this tectonic event. The 3 km wide NZ is a subvertical to steeply SSW dipping structure, parallel to the NE contact of the batholith, with well-developed foliation and mineral stretching lineations. Field and microstructural analyses defined the NZ as a medium-grade, non-coaxial, sinistral strike-slip shear zone. The transition from weak foliated granite to S-C mylonites and ultramylonites was observed. The sinistral shearing is consistent with E-W shortening in agreement with the tectonic framework of the ITZ. The low grade metasediments to the E of the granite are folded in N to NNW trending structures also implying E-W shortening. Temperature conditions during the deformation in ITZ and NZ inferred from microstructural analyses are about 500°-550°C. The

  20. Hot subluminous stars

    CERN Document Server

    Heber, Ulrich

    2016-01-01

    Hot subluminous stars of spectral type B and O are core helium-burning stars at the blue end of the horizontal branch or have evolved even beyond that stage. Strikingly, the distribution in the Hertzsprung-Russell diagram of He-rich vs. He-poor hot subdwarf stars of the globular clusters omega Cen and NGC~2808 differ from that of their field counterparts. The metal-abundance patterns of hot subdwarfs are typically characterized by strong deficiencies of some lighter elements as well as large enrichments of heavy elements. A large fraction of sdB stars are found in close binaries with white dwarf or very low-mass main sequence companions, which must have gone through a common-envelope phase of evolution.They provide a clean-cut laboratory to study this important but yet purely understood phase of stellar evolution. Substellar companions to sdB stars have also been found. For HW~Vir systems the companion mass distribution extends from the stellar into the brown dwarf regime. A giant planet to the pulsator V391 ...

  1. Blue Ribbon Panel Report

    Science.gov (United States)

    An NCI Cancer Currents blog by the NCI acting director thanking the cancer community for contributing to the Cancer Moonshot Blue Ribbon Panel report, which was presented to the National Cancer Advisory Board on September 7.

  2. New York Blue

    Data.gov (United States)

    Federal Laboratory Consortium — New York Blue is used cooperatively by the Laboratory and Stony Brook University as part of the New York Center for Computation Sciences. Ranked as the 28th fastest...

  3. Hormonal networks involved in apical hook development in darkness and their response to light

    Directory of Open Access Journals (Sweden)

    Maria Agustina Mazzella

    2014-02-01

    Full Text Available In darkness, the dicot seedlings produces an apical hook as result of differential cell division and extension at opposite sides of the hypocotyl. This hook protects the apical meristem from mechanical damage during seedling emergence from the soil. In darkness, gibberellins act via the DELLA-PIF (PHYTOCHROME INTERACTING FACTORs pathway, and ethylene acts via the EIN3/EIL1 (ETHYLENE INSENSITIE 3/EIN3 like 1-HLS1 (HOOKLESS 1 pathway to control the asymmetric accumulation of auxin required for apical hook formation and maintenance. These core pathways form a network with multiple points of connection. Light perception by phytochromes and cryptochromes reduces the activity of PIFs and CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1 --both required for hook formation in darkness--, lowers the levels of gibberellins, and triggers hook opening as a component of the switch between heterotrophic and photoautotrophic development. Apical hook opening is thus a suitable model to study the convergence of endogenous and exogenous signals on the control of cell division and cell growth.

  4. Stars and Star Myths.

    Science.gov (United States)

    Eason, Oliver

    Myths and tales from around the world about constellations and facts about stars in the constellations are presented. Most of the stories are from Greek and Roman mythology; however, a few Chinese, Japanese, Polynesian, Arabian, Jewish, and American Indian tales are also included. Following an introduction, myths are presented for the following 32…

  5. Star Product and Star Exponential

    OpenAIRE

    Tomihisa, Toshio; Yoshioka, Akira

    2010-01-01

    Here we extend the star products by means of complex symmetric matrices. In this way we obtain a family of star products. Next we consider the star exponentials with respect to these star products, and finally we obtain several interesting identities.

  6. Life Cycle of Stars

    Science.gov (United States)

    1999-01-01

    In this stunning picture of the giant galactic nebula NGC 3603, the crisp resolution of NASA's Hubble Space Telescope captures various stages of the life cycle of stars in one single view. To the upper left of center is the evolved blue supergiant called Sher 25. The star has a unique circumstellar ring of glowing gas that is a galactic twin to the famous ring around the supernova 1987A. The grayish-bluish color of the ring and the bipolar outflows (blobs to the upper right and lower left of the star) indicates the presence of processed (chemically enriched) material. Near the center of the view is a so-called starburst cluster dominated by young, hot Wolf-Rayet stars and early O-type stars. A torrent of ionizing radiation and fast stellar winds from these massive stars has blown a large cavity around the cluster. The most spectacular evidence for the interaction of ionizing radiation with cold molecular-hydrogen cloud material are the giant gaseous pillars to the right of the cluster. These pillars are sculptured by the same physical processes as the famous pillars Hubble photographed in the M16 Eagle Nebula. Dark clouds at the upper right are so-called Bok globules, which are probably in an earlier stage of star formation. To the lower left of the cluster are two compact, tadpole-shaped emission nebulae. Similar structures were found by Hubble in Orion, and have been interpreted as gas and dust evaporation from possibly protoplanetary disks (proplyds). This true-color picture was taken on March 5, 1999 with the Wide Field Planetary Camera 2.

  7. Quantum Hooke's law to classify pulse laser induced ultrafast melting.

    Science.gov (United States)

    Hu, Hao; Ding, Hepeng; Liu, Feng

    2015-02-03

    Ultrafast crystal-to-liquid phase transition induced by femtosecond pulse laser excitation is an interesting material's behavior manifesting the complexity of light-matter interaction. There exist two types of such phase transitions: one occurs at a time scale shorter than a picosecond via a nonthermal process mediated by electron-hole plasma formation; the other at a longer time scale via a thermal melting process mediated by electron-phonon interaction. However, it remains unclear what material would undergo which process and why? Here, by exploiting the property of quantum electronic stress (QES) governed by quantum Hooke's law, we classify the transitions by two distinct classes of materials: the faster nonthermal process can only occur in materials like ice having an anomalous phase diagram characterized with dTm/dP melting temperature and P is pressure, above a high threshold laser fluence; while the slower thermal process may occur in all materials. Especially, the nonthermal transition is shown to be induced by the QES, acting like a negative internal pressure, which drives the crystal into a "super pressing" state to spontaneously transform into a higher-density liquid phase. Our findings significantly advance fundamental understanding of ultrafast crystal-to-liquid phase transitions, enabling quantitative a priori predictions.

  8. Hooked flare ribbons and flux-rope related QSL footprints

    CERN Document Server

    Zhao, Jie; Aulanier, Guillaume; Schmieder, Brigitte; Pariat, Etienne; Li, Hui

    2016-01-01

    We studied the magnetic topology of active region 12158 on 2014 September 10 and compared it with the observations before and early in the flare which begins at 17:21 UT (SOL2014-09-10T17:45:00). Our results show that the sigmoidal structure and flare ribbons of this active region observed by SDO/AIA can be well reproduced from a Grad-Rubin non linear force free field extrapolation method. Various inverse-S and -J shaped magnetic field lines, that surround a coronal flux rope, coincide with the sigmoid as observed in different extreme ultraviolet wavelengths, including its multi-threaded curved ends. Also, the observed distribution of surface currents in the magnetic polarity where it was not prescribed is well reproduced. This validates our numerical implementation and set-up of the Grad-Rubin method. The modeled double inverse-J shaped Quasi-Separatrix Layer (QSL) footprints match the observed flare ribbons during the rising phase of the flare, including their hooked parts. The spiral-like shape of the latt...

  9. Automation Hooks Architecture Trade Study for Flexible Test Orchestration

    Science.gov (United States)

    Lansdowne, Chatwin A.; Maclean, John R.; Graffagnino, Frank J.; McCartney, Patrick A.

    2010-01-01

    We describe the conclusions of a technology and communities survey supported by concurrent and follow-on proof-of-concept prototyping to evaluate feasibility of defining a durable, versatile, reliable, visible software interface to support strategic modularization of test software development. The objective is that test sets and support software with diverse origins, ages, and abilities can be reliably integrated into test configurations that assemble and tear down and reassemble with scalable complexity in order to conduct both parametric tests and monitored trial runs. The resulting approach is based on integration of three recognized technologies that are currently gaining acceptance within the test industry and when combined provide a simple, open and scalable test orchestration architecture that addresses the objectives of the Automation Hooks task. The technologies are automated discovery using multicast DNS Zero Configuration Networking (zeroconf), commanding and data retrieval using resource-oriented Restful Web Services, and XML data transfer formats based on Automatic Test Markup Language (ATML). This open-source standards-based approach provides direct integration with existing commercial off-the-shelf (COTS) analysis software tools.

  10. VizieR Online Data Catalog: Young star groups in NGC 300 (Rodriguez+, 2016)

    Science.gov (United States)

    Rodriguez, M. J.; Baume, G.; Feinstein, C.

    2016-08-01

    Fundamental characteristics of 1147 young star groups identified in 6 ACS/WFC fields of the galaxy NGC 300. For each group: field of the ACS/WFC, equatorial coordinates, radius, number of stars (the suffix bri indicates bright stars with F555W<25, the suffix dct indicate stars belonging to the decontaminated region, the suffixes blue and red refer to blue and red stars respectively), the magnitude of the brightest star in the group, PDMF slope with its error, and galactocentric distance. (1 data file).

  11. The Blues of David Lynch

    OpenAIRE

    Roche, David

    2009-01-01

    This article is an attempt to elaborate a typology of the color blue in the color films of David Lynch up to and including Mulholland Drive (2001). The color blue is considered alternately as light, matter or verbal language. The author studies the use, function, value and meaning of blue lighting, divided into static and flashing light, and of the blue objects in Blue Velvet (1986) and Mulholland Drive. The author shows how Lynch appropriates connotations Western culture, under the influence...

  12. Hook and Roll Technique” Using an Articulating Hook Cautery to Provide a Critical View during Single-incision Laparoscopic Cholecystectomy

    Directory of Open Access Journals (Sweden)

    Kin,Hitoshi

    2013-08-01

    Full Text Available We describe a new simple and easy technique called the "Hook and roll technique" (HRT that uses an articulating hook cautery to provide a critical view during single incision laparoscopic cholecystectomy (SILC. A 2-cm incision is made at the umbilicus to insert three 5-mm trocars or a multichannel port. After dissection of the serosa of the dorsal and ventral sides of the gall bladder, including Calot's triangle, the angled tip of the hook cautery is inserted between the cystic artery and duct with its tip placed dorsally. The tip is then rotated in a clockwise manner to avoid bile duct injury, allowing the connective tissue between them to be hooked, coagulated and cut. This procedure is repeated several times, followed by dissection between the cystic artery and the liver bed to achieve a critical view. From December 2008 to May 2011, 121 patients underwent SILC using HRT in our hospital without any serious complications. This technique is suitable for SILC, as it is consists of simple procedures that can be performed safely and easily, even by left hand in a cross-over approach, and it allows complete dissection of Calot's triangle to achieve a critical view without using any dissector under dangerous in-line viewing.

  13. Case report of right hamate hook fracture in a patient with previous fracture history of left hamate hook: is it hamate bipartite?

    Directory of Open Access Journals (Sweden)

    Norton Sandra

    2006-10-01

    Full Text Available Abstract Background Hamate hook fracture is a common fracture in golfers and others who play sports that involve rackets or sticks such as tennis or hockey. This patient had a previous hamate fracture in the opposing wrist along with potential features of hamate bipartite. Case presentation A 19 year old male presented with a complaint of right wrist pain on the ulnar side of the wrist with no apparent mechanism of injury. The pain came on gradually one week before being seen in the office and he reported no prior care for the complaint. His history includes traumatic left hamate hook fracture with surgical excision. Conclusion The patient was found to have marked tenderness over the hamate and with a prior fracture to the other wrist, computed tomography of the wrist was ordered revealing a fracture to the hamate hook in the right wrist. He was referred for surgical evaluation and the hook of the hamate was excised. Post-surgically, the patient was able to return to normal activity within eight weeks. This case is indicative of fracture rather than hamate bipartite. This fracture should be considered in a case of ulnar sided wrist pain where marked tenderness is noted over the hamate, especially after participation in club or racket sports.

  14. Clavicle hook plate fixation for displaced lateral-third clavicle fractures (Neer type II): a functional outcome study.

    LENUS (Irish Health Repository)

    Good, Daniel W

    2012-08-01

    Controversy exists with the use of the acromioclavicular hook plate for the treatment of lateral-third clavicle fractures (Neer type II). This is thought to stem from problems associated with the hook plate causing impingement symptoms, which can cause long-term limitation of movement and pain. Our aim was to evaluate the functional outcomes of patients with lateral-third clavicle fractures treated with the hook plate.

  15. Stellar science from a blue wavelength range - A possible design for the blue arm of 4MOST

    CERN Document Server

    Hansen, C J; Seifert, W; Koch, A; Xu, W; Caffau, E; Christlieb, N; Korn, A J; Lind, K; Sbordone, L; Ruchti, G; Feltzing, S; de Jong, R S; Barden, S; Schnurr, O

    2015-01-01

    From stellar spectra, a variety of physical properties of stars can be derived. In particular, the chemical composition of stellar atmospheres can be inferred from absorption line analyses. These provide key information on large scales, such as the formation of our Galaxy, down to the small-scale nucleosynthesis processes that take place in stars and supernovae. By extending the observed wavelength range toward bluer wavelengths, we optimize such studies to also include critical absorption lines in metal-poor stars, and allow for studies of heavy elements (Z>38) whose formation processes remain poorly constrained. In this context, spectrographs optimized for observing blue wavelength ranges are essential, since many absorption lines at redder wavelengths are too weak to be detected in metal-poor stars. This means that some elements cannot be studied in the visual-redder regions, and important scientific tracers and science cases are lost. The present era of large public surveys will target millions of stars. ...

  16. ANALISA KEKUATAN KONSTRUKSI BRACKET TOWING HOOK PADA TB. BONTANG DENGAN METODE ELEMEN HINGGA DAN RULES BKI

    Directory of Open Access Journals (Sweden)

    Imam Pujo Mulyatno

    2013-01-01

    Full Text Available Bracket towing hook construction planning is to make a construction that has the stress level of the allowable limit and can be accepted by the construction. Requirements for towing hook are structural strength if the stress levels that occur below the elastic region. By calculating the value of the maximum load, maximum stress, von mises stress and deflection (displasment that occur in the construction of bracket towing hook, so that known security level of construction that has been designed. Research on construction of the strength bracket towing hook need to be considered and carried out, where the stress caused by load about them should not exceed the maximum limit σyield materials and σallow based on the rules from the class. The reference to rules used in this research is based on the rules of Bureau Classification Indonesia. Analysis of the strength bracket towing hook construction is done by using finite element methode. The analysis used is a static load analysis to determine the characteristics and location of greatest stress on the construction bracket towing hook based on three variations of loading. Analysis results obtained using finite element methode based program of greatest stress maximum occurs in the condition of the bracket towing hook  with maximum horse power load that is equal to 44,2 N/mm2 where the most critical area occurs at node 457 which is located at frame number 23 lengthwise section and stiffener number 7 cross section. This stress is still in a safe condition because after compared with material σyield of 400 N/mm2 and σallow based BKI rules of 178,12 N/mm2 produce safety factor value of 9,05 and 4,03

  17. Where the Blue Stragglers Roam: Searching for a Link Between Formation and Environment

    CERN Document Server

    Leigh, N; Knigge, C; Leigh, Nathan; Sills, Alison; Knigge, Christian

    2007-01-01

    The formation of blue stragglers is still not completely understood, particularly the relationship between formation environment and mechanism. We use a large, homogeneous sample of blue stragglers in the cores of 57 globular clusters to investigate the relationships between blue straggler populations and their environments. We use a consistent definition of ``blue straggler'' based on position in the color-magnitude diagram, and normalize the population relative to the number of red giant branch stars in the core. We find that the previously determined anti-correlation between blue straggler frequency and total cluster mass is present in the purely core population. We find some weak correlations with central velocity dispersion and with half-mass relaxation time. The blue straggler frequency does not show any trend with any other cluster parameter. Even though collisions may be expected to be a dominant blue straggler formation process in globular cluster cores, we find no correlation between the frequency o...

  18. Assessing the Personal Negative Impacts of Hooking Up Experienced by College Students: Gender Differences and Mental Health.

    Science.gov (United States)

    Napper, Lucy E; Montes, Kevin S; Kenney, Shannon R; LaBrie, Joseph W

    2016-09-01

    Hooking up is a normative behavior among college students that is associated with a range of positive and negative consequences. While previous research has primarily focused on women's negative experiences of hooking up, the current study explored the relationships among hooking up behaviors, psychological distress, and a broad range of negative effects of hooking up in both male and female college students. Using a multisite sample of college students, we developed the 14-item Negative Impact of Hookups Inventory (NIHI) to assess negative health outcomes, emotional responses, and social consequences associated with hooking up. Unprotected sex and having more hookup partners were associated with greater negative experiences of hooking up. Contrary to expectations, there were no gender differences in the total number of negative hookup effects, although men reported more frequent hookups. In addition, negative impacts of hooking up were positively associated with psychological distress regardless of gender. The NIHI may offer a useful tool to assess the negative impacts of hooking up. Understanding students' hookup experiences is an important step toward developing targeted health interventions related to hooking up behavior in young adult populations. PMID:26445346

  19. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star.......Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star....

  20. Beyond Deep Blue

    CERN Document Server

    Newborn, Monty

    2011-01-01

    More than a decade has passed since IBM's Deep Blue computer stunned the world by defeating Garry Kasparov, the world chess champion at that time. Beyond Deep Blue tells the continuing story of the chess engine and its steady improvement. The book provides analysis of the games alongside a detailed examination of the remarkable technological progress made by the engines - asking which one is best, how good is it, and how much better can it get. Features: presents a total of 118 games, played by 17 different chess engines, collected together for the first time in a single reference; details the

  1. A Blue Lagoon Function

    DEFF Research Database (Denmark)

    Markvorsen, Steen

    2007-01-01

    We consider a specific function of two variables whose graph surface resembles a blue lagoon. The function has a saddle point $p$, but when the function is restricted to any given straight line through $p$ it has a {\\em{strict local minimum}} along that line at $p$.......We consider a specific function of two variables whose graph surface resembles a blue lagoon. The function has a saddle point $p$, but when the function is restricted to any given straight line through $p$ it has a {\\em{strict local minimum}} along that line at $p$....

  2. The Blue Collar Brain

    Directory of Open Access Journals (Sweden)

    Guy eVan Orden

    2012-06-01

    Full Text Available Much effort has gone into elucidating control of the body by the brain, less so the role of the body in controlling the brain. This essay develops the idea that the brain does a great deal of work in the service of behavior that is controlled by the body, a blue collar role compared to the white collar control exercised by the body. The argument that supports a blue collar role for the brain is also consistent with recent discoveries clarifying the white collar role of synergies across the body's tensegrity structure, and the evidence of critical phenomena in brain and behavior.

  3. The Star Formation Camera

    CERN Document Server

    Scowen, Paul A; Beasley, Matthew; Calzetti, Daniela; Desch, Steven; Fullerton, Alex; Gallagher, John; Lisman, Doug; Macenka, Steve; Malhotra, Sangeeta; McCaughrean, Mark; Nikzad, Shouleh; O'Connell, Robert; Oey, Sally; Padgett, Deborah; Rhoads, James; Roberge, Aki; Siegmund, Oswald; Shaklan, Stuart; Smith, Nathan; Stern, Daniel; Tumlinson, Jason; Windhorst, Rogier; Woodruff, Robert

    2009-01-01

    The Star Formation Camera (SFC) is a wide-field (~15'x19, >280 arcmin^2), high-resolution (18x18 mas pixels) UV/optical dichroic camera designed for the Theia 4-m space-borne space telescope concept. SFC will deliver diffraction-limited images at lambda > 300 nm in both a blue (190-517nm) and a red (517-1075nm) channel simultaneously. Our aim is to conduct a comprehensive and systematic study of the astrophysical processes and environments relevant for the births and life cycles of stars and their planetary systems, and to investigate and understand the range of environments, feedback mechanisms, and other factors that most affect the outcome of the star and planet formation process. This program addresses the origins and evolution of stars, galaxies, and cosmic structure and has direct relevance for the formation and survival of planetary systems like our Solar System and planets like Earth. We present the design and performance specifications resulting from the implementation study of the camera, conducted ...

  4. Massive Stars

    Science.gov (United States)

    Livio, Mario; Villaver, Eva

    2009-11-01

    Participants; Preface Mario Livio and Eva Villaver; 1. High-mass star formation by gravitational collapse of massive cores M. R. Krumholz; 2. Observations of massive star formation N. A. Patel; 3. Massive star formation in the Galactic center D. F. Figer; 4. An X-ray tour of massive star-forming regions with Chandra L. K. Townsley; 5. Massive stars: feedback effects in the local universe M. S. Oey and C. J. Clarke; 6. The initial mass function in clusters B. G. Elmegreen; 7. Massive stars and star clusters in the Antennae galaxies B. C. Whitmore; 8. On the binarity of Eta Carinae T. R. Gull; 9. Parameters and winds of hot massive stars R. P. Kudritzki and M. A. Urbaneja; 10. Unraveling the Galaxy to find the first stars J. Tumlinson; 11. Optically observable zero-age main-sequence O stars N. R. Walborn; 12. Metallicity-dependent Wolf-Raynet winds P. A. Crowther; 13. Eruptive mass loss in very massive stars and Population III stars N. Smith; 14. From progenitor to afterlife R. A. Chevalier; 15. Pair-production supernovae: theory and observation E. Scannapieco; 16. Cosmic infrared background and Population III: an overview A. Kashlinsky.

  5. Maglev self-excited vibration suppression with a virtual sky-hooked damper

    Institute of Scientific and Technical Information of China (English)

    李金辉; 李杰; 周丹峰; 王连春

    2016-01-01

    This work addresses the problem of self-excited vibration, which degrades the stability of the levitation control, decreases the ride comfort, and restricts the construction cost of maglev system. Firstly, a minimum model containing a flexible bridge and a single levitation unit is presented. Based on the simplified model, the principle underlying the self-excited vibration is explored. After investigations about the energy transmission between the levitation system and bridge, it is concluded that the increment of modal damping can dissipate the accumulated energy by the bridge and the self-excited vibration may be avoided. To enlarge the equivalent modal damping of bridge, the sky-hooked damper is adopted. Furthermore, to avoid the hardware addition of real sky-hooked damper, considering the fact that the electromagnet itself is an excellent actuator that is capable of providing sufficiently fast and large force acting on the bridge to emulate the influence of the real sky-hooked damper, the technique of the virtual sky-hooked damper is proposed. The principle underlying the virtual sky-hooked damper by electromagnet is explored and the vertical velocity of bridge is estimated. Finally, numerical and experimental results illustrating the stability improvement of the vehicle-bridge interaction system are provided.

  6. The influence of pornography on sexual scripts and hooking up among emerging adults in college.

    Science.gov (United States)

    Braithwaite, Scott R; Coulson, Gwen; Keddington, Krista; Fincham, Frank D

    2015-01-01

    The explosive growth in access to the Internet has led to a commensurate increase in the availability, anonymity, and affordability of pornography. An emerging body of research has shown associations between pornography and certain behaviors and attitudes; yet, how pornography actually influences these outcomes has not been documented. In two studies (Study 1 N = 969; Study 2 N = 992) we examined the hypothesis that pornography influences potentially risky sexual behavior (hooking up) among emerging adults via sexual scripts. Our results demonstrate that more frequent viewing of pornography is associated with a higher incidence of hooking up and a higher number of unique hook up partners. We replicated these effects both cross-sectionally and longitudinally while accounting for the stability of hook ups over the course of an academic semester. We also demonstrated that more frequent viewing of pornography is associated with having had more previous sexual partners of all types, more one occasion sexual partners ("one night stands"), and plans to have a higher number of sexual partners in the future. Finally, we provided evidence that more permissive sexual scripts mediated the association between more frequent pornography viewing and hooking up. We discuss these findings with an eye toward mitigating potential personal and public health risks among emerging adults. PMID:25239659

  7. Grasp and force based taxonomy of split-hook prosthetic terminal devices.

    Science.gov (United States)

    Belter, Joseph T; Reynolds, Bo C; Dollar, Aaron M

    2014-01-01

    In this paper, we analyze the use of the body-powered split-hook prosthetic terminal device, which is the most commonly used upper-limb prosthesis. We developed two taxonomies of split-hook use, one on grasp shape and one on force exertion, illustrating the functional capabilities and use cases of the device. Video captured from an amputee using a body-powered split-hook during a number of common activities was used to lend weight to the completeness of the classifications. These taxonomies serve to establish a common language and means of comparing the types of grasps achievable by simple terminal devices to those of advanced myoelectric terminal devices or even human hands. The first taxonomy categorizes the grasp type based on the contacts with the environment while the second is categorized by the method and limitation of force exertion. We discuss the difference between grasps capable of holding objects compared to those that are capable of acquiring objects and the importance of non-prehensile uses of the split-hook. The classification schemes lay the groundwork for further detailed study of split-hook use, and the discussion of the use cases described may help guide terminal device developers to create improved prostheses. PMID:25571512

  8. Star Card:Blue Ocean of Fans Interest Export and Sports Collection%球星卡:球迷的“兴趣出口”与体育藏品的另类蓝海

    Institute of Scientific and Technical Information of China (English)

    杜恺

    2014-01-01

    体育藏品一直是宣传与弘扬体育文化的一个重要载体。从我国古代体育的蹴鞠到现代奥林匹克运动的器械,这些承载着历史价值的收藏品正不断地将体育的核心价值传递给世人。本文通过研究分析篮球球星卡的收藏价值和文化内涵,得出该类收藏的前景可观,意义深远,在我国篮球迷中具有可观的推广价值,并对推动篮球运动,加深篮球文化能够起到举足轻重的作用。%sports collections isan important carrier of publicity and promotion of sports culture .From Cuju ball sports in ancient China to the modern Olympic movement device , which carry the historical value of the collections are the core value of sports to the world .Through analysis and research of basketball star card collection value and cultural connotation, the author of this collectionis promising , far-reaching, and has considerable application value in theChinesebasketball fans , and to promote basketball sport , deepen thebasketball culture can play a deci-sive role.

  9. A MEGACAM SURVEY OF OUTER HALO SATELLITES. II. BLUE STRAGGLERS IN THE LOWEST STELLAR DENSITY SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Santana, Felipe A.; Munoz, Ricardo R. [Departamento de Astronomia, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago (Chile); Geha, Marla [Astronomy Department, Yale University, New Haven, CT 06520 (United States); Cote, Patrick; Stetson, Peter [Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, BC, V9E 2E7 (Canada); Simon, Joshua D. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Djorgovski, S. G., E-mail: fsantana@das.uchile.cl, E-mail: rmunoz@das.uchile.cl [Astronomy Department, California Institute of Technology, Pasadena, CA, 91125 (United States)

    2013-09-10

    We present a homogeneous study of blue straggler stars across 10 outer halo globular clusters, 3 classical dwarf spheroidal galaxies, and 9 ultra-faint galaxies based on deep and wide-field photometric data taken with MegaCam on the Canada-France-Hawaii Telescope. We find blue straggler stars to be ubiquitous among these Milky Way satellites. Based on these data, we can test the importance of primordial binaries or multiple systems on blue straggler star formation in low-density environments. For the outer halo globular clusters, we find an anti-correlation between the specific frequency of blue stragglers and absolute magnitude, similar to that previously observed for inner halo clusters. When plotted against density and encounter rate, the frequency of blue stragglers is well fit by a single trend with a smooth transition between dwarf galaxies and globular clusters; this result points to a common origin for these satellites' blue stragglers. The fraction of blue stragglers stays constant and high in the low encounter rate regime spanned by our dwarf galaxies, and decreases with density and encounter rate in the range spanned by our globular clusters. We find that young stars can mimic blue stragglers in dwarf galaxies only if their ages are 2.5 {+-} 0.5 Gyr and they represent {approx}1%-7% of the total number of stars, which we deem highly unlikely. These results point to mass-transfer or mergers of primordial binaries or multiple systems as the dominant blue straggler formation mechanism in low-density systems.

  10. Infrared properties of Active OB stars in the Magellanic Clouds from the Spitzer SAGE Survey

    OpenAIRE

    Bonanos, A. Z.; Lennon, D.J.; Massa, D. L.; Sewilo, M.; Köhlinger, F.; Panagia, N.; van Loon, J. Th.; Evans, C. J.; Smith, L J; Meixner, M.; Gordon, K; teams, the SAGE

    2010-01-01

    We present a study of the infrared properties of 4922 spectroscopically confirmed massive stars in the Large and Small Magellanic Clouds, focusing on the active OB star population. Besides OB stars, our sample includes yellow and red supergiants, Wolf-Rayet stars, Luminous Blue Variables (LBVs) and supergiant B[e] stars. We detect a distinct Be star sequence, displaced to the red, and find a higher fraction of Oe and Be stars among O and early-B stars in the SMC, respectively, when compared t...

  11. Blue-green algae

    Science.gov (United States)

    ... for 6 months relieves allergy symptoms in adults. Arsenic poisoning. Early research shows that taking a combination of blue-green algae and zinc by mouth twice daily for 12 weeks reduces arsenic levels and its effects on the skin in ...

  12. The Blue Denmark

    DEFF Research Database (Denmark)

    Hansen, Carsten Ørts; Sornn-Friese, Henrik

    This paper makes an important contribution to the discussion about knowledge based localised externalities in the context of shipping and the maritime sector in Denmark. In the paper we ask if there is a national, knowledge‐based maritime cluster configured around the shipowners in Denmark. This ...... talk about The Blue Denmark....

  13. The "Blue Banana" Revisited

    NARCIS (Netherlands)

    Faludi, A.K.F.

    2015-01-01

    This essay is about the “Blue Banana”. Banana is the name given subsequently by others to a Dorsale européenne (European backbone) identified empirically by Roger Brunet. In a background study to the Communication of the European Commission ‘Europe 2000’, Klaus Kunzmann and Michael Wegener put forwa

  14. The BlueTides Simulation: First Galaxies and Reionization

    CERN Document Server

    Feng, Yu; Croft, Rupert A; Bird, Simeon; Battaglia, Nicholas; Wilkins, Stephen

    2015-01-01

    We introduce the BlueTides simulation and report initial results for the luminosity functions of the first galaxies and AGN, and their contribution to reionization. BlueTides was run on the BlueWaters cluster at NCSA from $z=99$ to $z=8.0$ and includes 2$\\times$7040$^3$ particles in a $400$Mpc/h per side box, making it the largest hydrodynamic simulation ever performed at high redshift. BlueTides includes a pressure-entropy formulation of smoothed particle hydrodynamics, gas cooling, star formation (including molecular hydrogen), black hole growth and models for stellar and AGN feedback processes. The star formation rate density in the simulation is a good match to current observational data at $z\\sim 8-10$. We find good agreement between observations and the predicted galaxy luminosity function in the currently observable range $-18\\le M_{\\mathrm UV} \\le -22.5$ with some dust extinction required to match the abundance of brighter objects. BlueTides implements a patchy reionization model that produces a fluct...

  15. Hadron star models. [neutron stars

    Science.gov (United States)

    Cohen, J. M.; Boerner, G.

    1974-01-01

    The properties of fully relativistic rotating hadron star models are discussed using models based on recently developed equations of state. All of these stable neutron star models are bound with binding energies as high as about 25%. During hadron star formation, much of this energy will be released. The consequences, resulting from the release of this energy, are examined.

  16. CRAFTING THE MICROWORLD: HOW ROBERT HOOKE CONSTRUCTED KNOWLEDGE ABOUT SMALL THINGS.

    Science.gov (United States)

    Lawson, Ian

    2016-03-20

    This paper investigates the way in which Robert Hooke constructed his microscopical observations. His Micrographia is justifiably famous for its detailed engravings, which communicated Hooke's observations of tiny nature to his readers, but less attention has been paid to how he went about making the observations themselves. In this paper I explore the relationship between the materiality of his instrument and the epistemic images he produced. Behind the pictures lies an array of hidden materials, and the craft knowledge it took to manipulate them. By investigating the often counter-theoretical and conflicting practices of his ingenious microscope use, I demonstrate the way in which Hooke crafted the microworld for his readers, giving insight into how early modern microscopy was understood by its practitioners and audience.

  17. Repositioning of premaxilla in bilateral cleft lip and palate using a "J-hook headgear".

    Science.gov (United States)

    Kecik, Defne; Enacar, Ayhan

    2006-11-01

    The purpose of this clinical approach is to present the successful treatment of the severely protruded and extruded premaxilla with high-pull J-hook headgear. Two patients with bilateral cleft lip and palate deformity and a protruding and extruding premaxilla causing a deep bite were treated with high-pull J-hook headgear and fixed orthodontic appliances. The lateral cephalometric measurements before and after orthodontic treatment were evaluated with Ricketts analysis. The premaxillae of the two patients were repositioned, correcting the deep overbite and overjet and a well-functioning occlusion was attained. The repositioning of an inferiorly positioned and protruded premaxilla with J-hook headgear is an alternative treatment approach compared to other treatment modalities.

  18. Classification of O Stars in the Yellow-Green: The Exciting Star VES 735

    OpenAIRE

    Kerton, C. R.; Ballantyne, D. R.; Martin, P. G.

    1999-01-01

    Acquiring data for spectral classification of heavily reddened stars using traditional criteria in the blue-violet region of the spectrum can be prohibitively time consuming using small to medium sized telescopes. One such star is the Vatican Observatory emission-line star VES 735, which we have found excites the HII region KR140. In order to classify VES 735, we have constructed an atlas of stellar spectra of O stars in the yellow-green (4800 - 5420 A). We calibrate spectral type versus the ...

  19. Biomechanical and clinical study on screw hook fixation after direct repair of lumbar spondylolysis

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jian; LIU Fan; SHI Hong-guang; FAN Jian; ZHAO Wei-dong; WANG You-hua; CAI Yu-hui

    2006-01-01

    Objective: To evaluate the biomechanical effect and clinical results of hook screw fixation after direct repair of lumbar spondylous defects in the pars interarticularis.Methods: L2-L6 spines of 8 fresh-frozen and thawed calf cadavers were used for mechanical testing. Bilateral spondylous defects were created in the L4 vertebra. The intervertebral rotation ranges between L4 and Ls were scanned and computerized in various states of motion, such as flexion/extension, lateral bending and torsional loadings applied on the intact spine and the spondylous spine when the spondylous spine was fixed with modified Scott's fixation, hook screw fixation and Buck's fixation sequentially and respectively. Between July 2002 and February 2004, 14 young male patients (aged 15-31 years)suffering from symptomatic lumbar spondylolysis were treated with TSRH hook screw fixation after direct repair of the defects. MacNab criteria1 were used to assess their preand post-operative status.Results: Each fixation technique could significantly increase the intervertebral rotational stiffness and made the stiffness return to nearly the intact level. Hook screw technique provided more rotational stability than the others. Hook screw and Buck's techniques provided more flexion/extension stability than modified Scott's technique.Neither complication nor instrumental failure was observed in this study. The mean follow-up period was 21 months.All the patients except one acquired union during the follow-up period. Thirteen patients had a "good" or "excellent" result according to MacNab criteria.Conclusions: Hook screw fixation shows biomechanical advantages and is safe and effective for young patients with lumbar spondylolysis.

  20. Simultaneous Multiple Preoperative Localizations of Small Pulmonary Lesions Using a Short Hook Wire and Suture System

    Energy Technology Data Exchange (ETDEWEB)

    Iguchi, Toshihiro, E-mail: iguchi@ba2.so-net.ne.jp; Hiraki, Takao, E-mail: takaoh@tc4.so-net.ne.jp; Gobara, Hideo, E-mail: gobara@cc.okayama-u.ac.jp; Fujiwara, Hiroyasu, E-mail: hirofujiwar@gmail.com; Matsui, Yusuke, E-mail: wckyh140@yahoo.co.jp [Okayama University Medical School, Department of Radiology (Japan); Sugimoto, Seiichiro, E-mail: sei1675sugi@yahoo.co.jp; Toyooka, Shinichi, E-mail: shintoyooka@gmail.com; Oto, Takahiro, E-mail: yellowpeachoto@hotmail.com; Miyoshi, Shinichiro, E-mail: smiyoshi@md.okayama-u.ac.jp [Okayama University Medical School, Department of General Thoracic Surgery (Japan); Kanazawa, Susumu, E-mail: susumu@cc.okayama-u.ac.jp [Okayama University Medical School, Department of Radiology (Japan)

    2015-08-15

    PurposeThe aim of the study was to retrospectively evaluate simultaneous multiple hook wire placement outcomes before video-assisted thoracoscopic surgery (VATS).Materials and MethodsThirty-eight procedures were performed on 35 patients (13 men and 22 women; mean age, 59.9 years) with 80 lung lesions (mean diameter 7.9 mm) who underwent simultaneous multiple hook wire placements for preoperative localizations. The primary endpoints were technical success, complications, procedure duration, and VATS outcome; secondary endpoints included comparisons between technical success rates, complication rates, and procedure durations of the 238 single-placement procedures performed. Complications were also evaluated.ResultsIn 35 procedures including 74 lesions, multiple hook wire placements were technically successful; in the remaining three procedures, the second target placement was aborted because of massive pneumothorax after the first placement. Although complications occurred in 34 procedures, no grade 3 or above adverse event was observed. The mean procedure duration was 36.4 ± 11.8 min. Three hook wires dislodged during patient transport to the surgical suite. Seventy-four successfully marked lesions were resected. Six lesions without hook wires were successfully resected after detection by palpation with an additional mini-thoracotomy or using subtle pleural changes as a guide. The complication rates and procedure durations of multiple-placement procedures were significantly higher (P = 0.04) and longer (P < 0.001) than those in the single-placement group, respectively, while the technical success rate was not significantly different (P = 0.051).ConclusionsSimultaneous multiple hook wire placements before VATS were clinically feasible, but increased the complication rate and lengthened the procedure time.

  1. Subsurface macro-inclusions and solidified hook character in aluminum-killed deep-drawing steel slabs

    Institute of Scientific and Technical Information of China (English)

    Xiao-xuan Deng; Lin-ping Li; Xin-hua Wang; Yun-qing Ji; Chen-xi Ji; Guo-sen Zhu

    2014-01-01

    Subsurface macro-inclusions and hooks are detrimental to the surface quality of deep-drawing steel sheets. However, little is known about the relationship between macro-inclusions and hooks. Thus, in this work, two ultralow carbon (ULC) steel slabs and two low carbon (LC) aluminum-killed steel slabs were sampled to study the relationship between hooks and subsurface macro-inclusions, which were detected on the cross-sections of steel samples with an area of 56058 mm2 using an automated scanning electron microscopy/energy-disper-sive X-ray spectroscopy system. Results show that subsurface inclusions larger than 200 μm were almost entrapped by hook structures, whereas the location of other inclusions smaller than 200μm had no obvious dependence on the location of solidified hooks. Furthermore, the number density (ND) of subsurface inclusions larger than 200μm decreased from 0.02 to 0 cm-2 in ULC steel as the mean hook depth decreased from 1.57 to 1.01 mm. Similar trends were also observed in LC steel. In addition, the detected inclusions larger than 200μm were concentrated in the region near the slab center (3/8 width-5/8 width), where hook depths were also larger than those at any other locations. Therefore, minimizing the hook depth is an effective way to reduce inclusion-induced sliver defects in deep-drawing steels.

  2. A Novel Diterpenoid,11—O—β—D—glucopyranosylneo—triptophenolide, from Tripterygium wilfordii Hook.f

    Institute of Scientific and Technical Information of China (English)

    SongZhao; GuangZhongYANG; 等

    2002-01-01

    A new diterpenoid was isolated from the ethanolic extract of the dried root bark of Tripterygium wilfordii Hook.f. It is the first example of abietane diterpenoid glycoside isolated from Tripterygium wilfordii Hook.f.Its structure was identified to be 11-0-β-D-glucopyranosyl-neotriptophenolide based on spectral methods.

  3. The ′hook effect′ on serum prolactin estimation in a patient with macroprolactinoma.

    Directory of Open Access Journals (Sweden)

    Unnikrishnan A

    2001-01-01

    Full Text Available Large quantities of antigen in an immunoassay system impair antigen-antibody binding, resulting in low antigen determination. This is called the ′high dose hook effect′. We report this phenomenon in a patient with a large macroprolactinoma. In this patient, the correct estimate of serum prolactin (PRL was obtained only after appropriate dilution of serum. We suggest that in order to avoid the high dose hook effect, the serum PRL be estimated in appropriate dilution in all patients with large pituitary tumours. This is particularly important when the clinical suspicion of high PRL is strong, as in women with amenorrhoea-galactorrhoea and men with long standing hypogonadism.

  4. Automation Hooks Architecture for Flexible Test Orchestration - Concept Development and Validation

    Science.gov (United States)

    Lansdowne, C. A.; Maclean, John R.; Winton, Chris; McCartney, Pat

    2011-01-01

    The Automation Hooks Architecture Trade Study for Flexible Test Orchestration sought a standardized data-driven alternative to conventional automated test programming interfaces. The study recommended composing the interface using multicast DNS (mDNS/SD) service discovery, Representational State Transfer (Restful) Web Services, and Automatic Test Markup Language (ATML). We describe additional efforts to rapidly mature the Automation Hooks Architecture candidate interface definition by validating it in a broad spectrum of applications. These activities have allowed us to further refine our concepts and provide observations directed toward objectives of economy, scalability, versatility, performance, severability, maintainability, scriptability and others.

  5. High-angular resolution observations of the Pistol Star

    CERN Document Server

    Martayan, Christophe; Bouquin, Jean-Baptiste Le; Merand, Antoine; Montagnier, Guillaume; Selman, Fernando; Girard, Julien; Fox, Andrew; Baade, Dietrich; Fremat, Yves; Lobel, Alex; Martins, Fabrice; Patru, Fabien; Rivinius, Thomas; Sana, Hugues; Stefl, Stan; Zorec, Jean; Semaan, Thierry

    2010-01-01

    First results of near-IR adaptive optics (AO)-assisted imaging, interferometry, and spectroscopy of this Luminous Blue Variable (LBV) are presented. They suggest that the Pistol Star is at least double. If the association is physical, it would reinforce questions concerning the importance of multiplicity for the formation and evolution of extremely massive stars.

  6. Anatomia da madeira de Acacia bonariensis Gill. ex Hook. et Arn. Wood anatomy of Acacia bonariensis Gill. ex Hook. et Arn.

    Directory of Open Access Journals (Sweden)

    José Newton Cardoso Marchiori

    1996-08-01

    Full Text Available O objetivo do presente trabalho é a descrição anatômica da madeira de Acacia bonariensis Gill. Hook. et Arn. A estrutura anatômica é comparada com outras espécies sul-brasileiras do mesmo gênero. A presença de raios multisseriados estreitos e fibras septadas permitem classificar a espécie na série Vulgares Bentham ou sub-gênero Aculeiferum Vassal.The wood anatomy of Acacia bonariensis Gill. ex Hook. et Arn. is described and compared with other south-american Acacias. The presence of narrow multisseriate rays and libriform fibres, observed in the wood, are commonly found among species of the series Vulgares Benth. or sub-genus Aculeiferum Vassal.

  7. Hot Subluminous Stars

    Science.gov (United States)

    Heber, U.

    2016-08-01

    Hot subluminous stars of spectral type B and O are core helium-burning stars at the blue end of the horizontal branch or have evolved even beyond that stage. Most hot subdwarf stars are chemically highly peculiar and provide a laboratory to study diffusion processes that cause these anomalies. The most obvious anomaly lies with helium, which may be a trace element in the atmosphere of some stars (sdB, sdO) while it may be the dominant species in others (He-sdB, He-sdO). Strikingly, the distribution in the Hertzsprung–Russell diagram of He-rich versus He-poor hot subdwarf stars of the globular clusters ω Cen and NGC 2808 differ from that of their field counterparts. The metal-abundance patterns of hot subdwarfs are typically characterized by strong deficiencies of some lighter elements as well as large enrichments of heavy elements. A large fraction of sdB stars are found in close binaries with white dwarf or very low-mass main sequence companions, which must have gone through a common-envelope (CE) phase of evolution. Because the binaries are detached they provide a clean-cut laboratory to study this important but yet poorly understood phase of stellar evolution. Hot subdwarf binaries with sufficiently massive white dwarf companions are viable candidate progenitors of type Ia supernovae both in the double degenerate as well as in the single degenerate scenario as helium donors for double detonation supernovae. The hyper-velocity He-sdO star US 708 may be the surviving donor of such a double detonation supernova. Substellar companions to sdB stars have also been found. For HW Vir systems the companion mass distribution extends from the stellar into the brown dwarf regime. A giant planet to the acoustic-mode pulsator V391 Peg was the first discovery of a planet that survived the red giant evolution of its host star. Evidence for Earth-size planets to two pulsating sdB stars have been reported and circumbinary giant planets or brown dwarfs have been found around HW

  8. Hot Subluminous Stars

    Science.gov (United States)

    Heber, U.

    2016-08-01

    Hot subluminous stars of spectral type B and O are core helium-burning stars at the blue end of the horizontal branch or have evolved even beyond that stage. Most hot subdwarf stars are chemically highly peculiar and provide a laboratory to study diffusion processes that cause these anomalies. The most obvious anomaly lies with helium, which may be a trace element in the atmosphere of some stars (sdB, sdO) while it may be the dominant species in others (He-sdB, He-sdO). Strikingly, the distribution in the Hertzsprung-Russell diagram of He-rich versus He-poor hot subdwarf stars of the globular clusters ω Cen and NGC 2808 differ from that of their field counterparts. The metal-abundance patterns of hot subdwarfs are typically characterized by strong deficiencies of some lighter elements as well as large enrichments of heavy elements. A large fraction of sdB stars are found in close binaries with white dwarf or very low-mass main sequence companions, which must have gone through a common-envelope (CE) phase of evolution. Because the binaries are detached they provide a clean-cut laboratory to study this important but yet poorly understood phase of stellar evolution. Hot subdwarf binaries with sufficiently massive white dwarf companions are viable candidate progenitors of type Ia supernovae both in the double degenerate as well as in the single degenerate scenario as helium donors for double detonation supernovae. The hyper-velocity He-sdO star US 708 may be the surviving donor of such a double detonation supernova. Substellar companions to sdB stars have also been found. For HW Vir systems the companion mass distribution extends from the stellar into the brown dwarf regime. A giant planet to the acoustic-mode pulsator V391 Peg was the first discovery of a planet that survived the red giant evolution of its host star. Evidence for Earth-size planets to two pulsating sdB stars have been reported and circumbinary giant planets or brown dwarfs have been found around HW

  9. The Blue Emu

    Science.gov (United States)

    Descalzi, Doug; Gillett, John; Gordon, Carlton; Keener, ED; Novak, Ken; Puente, Laura

    1993-01-01

    The primary goal in designing the Blue Emu was to provide an airline with a cost efficient and profitable means of transporting passengers between the major cities in Aeroworld. The design attacks the market where a demand for inexpensive transportation exists and for this reason the Blue Emu is an attractive investment for any airline. In order to provide a profitable aircraft, special attention was paid to cost and economics. For example, in manufacturing, simplicity was stressed in structural design to reduce construction time and cost. Aerodynamic design employed a tapered wing which reduced the induced drag coefficient while also reducing the weight of the wing. Even the propulsion system was selected with cost effectiveness in mind, yet also to maintain the marketability of the aircraft. Thus, in every aspect of the design, consideration was given to economics and marketability of the final product.

  10. Morphometric Analysis of Larval Rostellar Hooks in Taenia multiceps of Sheep in Iran and Its Association with Mitochondrial Gene Variability.

    Directory of Open Access Journals (Sweden)

    Sima Rostami

    2013-12-01

    Full Text Available The purposes of the present study were morphometric characterization of rostellar hooks of Taenia multiceps and to investigate the association of hook length variation and the variability within two mitochondrial genes of sheep isolates of the parasite.Up to 4500 sheep brains were examined for the presence of C. cerebralis. Biometric characters based on the larval rostellar hook size were measured for each individual isolate. Representative mitochondrial CO1 and 12S rRNA gene sequences for each of the isolates were obtained from NCBI GenBank. Morphometric and genetic data were analyzed using cluster analysis, Interclass Correlation Coefficient (ICC and random effects model.One hundred and fourteen sheep (2.5% were found infected with the coenuri. The minimum and maximum number of scoleces per cyst was 40 and 550 respectively. Each scolex contained 22-27 hooks arranged in two rows of large and small hooks. The average total length of the large and small hooks was 158.9 and 112.1 μm, respectively. Using ICC, statistically significant clusters of different hook sizes were identified within the isolates. The length of the large and small hooks was significantly associated with the variability in mitochondrial 12S rRNA gene.Taenia multiceps, is a relatively important zoonotic infection in Iranian sheep with the prevalence rate of 2.5%. Hook length analysis revealed statistically significant difference among individual isolates. Associations between the rostellar hook length and variability in the mitochondrial 12S rRNA was documented.

  11. Descriptive and injunctive social norm overestimation in hooking up and their role as predictors of hook-up activity in a college student sample.

    Science.gov (United States)

    Barriger, Megan; Vélez-Blasini, Carlos J

    2013-01-01

    This study examined the presence of norm overestimation in both injunctive and descriptive norms about hooking up. An online survey was completed by 186 college students (127 women). Overestimation was examined for hooking up as a global category, as well as for six specific behaviors. The role of norms in predicting hooking up was also examined using hierarchical multiple regression analyses. The predictive role of sensation-seeking, sociosexual orientation, self-esteem, and alcohol drinking status was also examined. Injunctive norm overestimation was present for less intimate behaviors (kissing and non-genital touching); only women showed overestimation for more intimate behaviors (genital touching, receiving oral sex, giving oral sex, and intercourse). Descriptive norms were overestimated across the board. Injunctive norms were poor predictors of behavior. Descriptive norms were good predictors only for less intimate behaviors, a pattern similar to that observed for drinking status. Ultimately, participants' level of personal comfort was the best predictor of participation in the most intimate behaviors, including oral sex and sexual intercourse. PMID:21919644

  12. Synthesizing a Blue Ocean

    OpenAIRE

    Vester, Daniel

    2012-01-01

    The purpose of this Master thesis was to determine how electronic musical instrument companies could utilize innovation strategies to add value to their products and create new business markets beyond their core. The theoretical framework was established by outlining competitive strategies suitable for adoption by electronic musical instrument companies. The Blue Ocean Strategy was compared to traditional competitive strategies such as Porter’s Five Forces, and subsequently chosen because of ...

  13. Star Formation and the Growth of Stellar Mass

    CERN Document Server

    Bell, Eric F; Papovich, Casey; Borch, Andrea; Wolf, Christian; Meisenheimer, Klaus

    2007-01-01

    Recent observations have demonstrated a significant growth in the integrated stellar mass of the red sequence since z=1, dominated by a steadily increasing number of galaxies with stellar masses M* 3x10^10 M_sun blue galaxies would also be overproduced; i.e., most of the new stars formed in blue cloud galaxies are in the massive galaxies. We explore a simple truncation scenario in which these `extra' blue galaxies have their star formation suppressed by an unspecified mechanism or mechanisms; simple cessation of star formation in these extra blue galaxies is approximately sufficient to build up the red seq uence at M*<10^11 M_sun.

  14. Shooting stars

    Energy Technology Data Exchange (ETDEWEB)

    Maurette, M.; Hammer, C.

    A shooting star passage -even a star shower- can be sometimes easily seen during moonless black night. They represent the partial volatilization in earth atmosphere of meteorites or micrometeorites reduced in cosmic dusts. Everywhere on earth, these star dusts are searched to be gathered. This research made one year ago on the Greenland ice-cap is the object of this article; orbit gathering projects are also presented.

  15. A Megacam Survey of Outer Halo Satellites. II. Blue Stragglers in the Lowest Stellar Density Systems

    CERN Document Server

    Santana, Felipe A; Geha, Marla; Cote, Patrick; Stetson, Peter; Simon, Joshua D; Djorgovski, S G

    2013-01-01

    We present a homogeneous study of blue straggler stars across ten outer halo globular clusters, three classical dwarf spheroidal and nine ultra-faint galaxies based on deep and wide-field photometric data taken with MegaCam on the Canada-France-Hawaii Telescope. We find blue straggler stars to be ubiquitous among these Milky Way satellites. Based on these data, we can test the importance of primordial binaries or multiple systems on blue straggler star formation in low density environments. For the outer halo globular clusters we find an anti-correlation between the specific frequency of blue straggler and absolute magnitude, similar to that previously observed for inner halo clusters. When plotted against density and encounter rate, the frequency of blue stragglers are well fitted by single trends with smooth transitions between dwarf galaxies and globular clusters, which points to a common origin for their blue stragglers. The fraction of blue stragglers stays constant and high in the low encounter rate reg...

  16. Constraining the Axion-Photon Coupling with Massive Stars

    CERN Document Server

    Friedland, Alexander; Wise, Michael

    2012-01-01

    We point out that stars in the mass window ~ 8-12 Msun can serve as sensitive probes of the axion-photon interaction, g_{A\\gamma\\gamma}. Specifically, for these stars axion energy losses from the helium-burning core would shorten and eventually eliminate the blue loop phase of the evolution. This would contradict observational data, since the blue loops are required, e.g., to account for the existence of Cepheid stars. Using the MESA stellar evolution code, modified to include the extra cooling, we conservatively find g_{A\\gamma\\gamma} <~ 0.8 * 10^{-10} GeV^{-1}, which compares favorably with the existing bounds.

  17. Visual Distortions Near a Neutron Star and Black Hole

    OpenAIRE

    Nemiroff, Robert J.

    1993-01-01

    The visual distortion effects visible to an observer traveling around and descending to the surface of an extremely compact star are described. Specifically, trips to a ``normal" neutron star, a black hole, and an ultracompact neutron star with extremely high surface gravity, are described. Concepts such as multiple imaging, red- and blue-shifting, conservation of surface brightness, the photon sphere, and the existence of multiple Einstein rings are discussed in terms of what the viewer woul...

  18. Pre-supernova mass loss predictions for massive stars

    OpenAIRE

    Vink, Jorick S.; de Koter, Alex; Kotak, Rubina

    2006-01-01

    Massive stars and supernovae (SNe) have a huge impact on their environment. Despite their importance, a comprehensive knowledge of which massive stars produce which SNe is hitherto lacking. We use a Monte Carlo method to predict the mass-loss rates of massive stars in the Hertzsprung-Russell Diagram (HRD) covering all phases from the OB main sequence, the unstable Luminous Blue Variable (LBV) stage, to the final Wolf-Rayet (WR) phase. Although WR produce their own metals, a strong dependence ...

  19. The Gaia Attitude Star Catalog

    Science.gov (United States)

    Smart, R. L.

    2016-04-01

    We describe the Attitude Star Catalog produced for the Gaia mission. This catalog is being used by Gaia for the first on-ground attitude reconstruction. Originally it was simply a subset of the Initial Gaia Source List but this subset did not meet the isolation requirements and it contained a significant number of double entries. As a result during the commissioning phase of Gaia a new generation of this catalog, that better fulfills the attitude reconstruction requirements, was requested. Here we describe the production and properties of this new Attitude Star Catalog. The Attitude Star Catalog was made by combining 7 all sky catalogs and selecting entries based on magnitude, isolation and astrometric precision criteria. The catalog has 8173331 entries with estimates of the positions at 2000, proper motions and magnitudes (Gaia G, Gaia Grvs, red RF & blue BJ) in the magnitude range 7.0 publically available from the CDS Strasbourg and the IGSL web-site.

  20. Massive Stars in the Quintuplet Cluster

    CERN Document Server

    Figer, D F; Morris, M; Figer, Donald F.; Lean, Ian S. Mc

    1999-01-01

    We present near-infrared photometry and K-band spectra of newly-identified massive stars in the Quintuplet Cluster, one of the three massive clusters projected within 50 pc of the Galactic Center. We find that the cluster contains a variety of massive stars, including more unambiguously identified Wolf-Rayet stars than any cluster in the Galaxy, and over a dozen stars in earlier stages of evolution, i.e., LBV, Ofpe/WN9, and OB supergiants. One newly identified star is the second ``Luminous Blue Variable'' in the cluster, after the ``Pistol Star.'' Given the evolutionary stages of the identified stars, the cluster appears to be about 4 \\pm 1 Myr old, assuming coeval formation. The total mass in observed stars is $\\sim 10^3 \\Msun$, and the implied mass is initial mass function. The implied mass density in stars is at least a few thousand $\\Msun pc^{-3}$. The newly-identified stars increase the estimated ionizing flux from this cluster by about an order of magnitude with respect to earlier estimates, to 10^{50.9...

  1. Bromus carinatus Hook. et Arn. en Puccinellia distans (L.) Parl. in Midden-Nederland

    NARCIS (Netherlands)

    Floristenclub Gelderse Vallei,

    1979-01-01

    The authors mention the occurrence of two grasses, Bromus carinatus Hook, et Arn. (fig. 1) and Puccinellia distans (L.) Parl. (fig. 2) in the central part of the Netherlands. The first is a naturalised adventitious plant, the other a species of saline habitats and is spreading through this part of o

  2. Cheating, Hooking Up, and Attention to Romantic Alternatives among College Students

    Science.gov (United States)

    Buri, John R.; Cromett, Cristina E.; Pappas, Sarah J.

    2014-01-01

    While numerous studies have emphasized more situational factors related to cheating, hooking up, and attention to romantic alternatives (e.g., alcohol use, need fulfillment, opportunity), the present findings support Finkel el al.'s (2012) argument for greater attentiveness to personal factors intrinsic to the individual that may influence…

  3. The mediatization of public sex cultures in the case of the hook-up app Grindr

    DEFF Research Database (Denmark)

    Jørgensen, Kristian Møller

    of mediatization” (Jansson, 2015) by looking at how personal biographies partake in the understanding and use of hook-up apps as social techniques and/or cultural properties. References Hollister, J. W. (2002). Reconstructing Social Theory at a Cruising Site. Dissertation Abstracts International, A: The Humanities...

  4. An Effective Method for Protecting Native API Hook Attacks in User-mode

    Directory of Open Access Journals (Sweden)

    K. Muthumanickam

    2015-01-01

    Full Text Available Today, many modern malware developers is taking the advantage of Application Programming Interface (API hook technique to take the control of the victim computer which making it difficult to detect their presence. Because of the sophistication of rootkit tools, a remote attacker can use native API to compromise any computer which can later be used for many illegal activities such as sniffing network lines, capturing passwords, sending spam and DDoS attack, etc. Thus to protect end-system by identifying and preventing native API malicious code hooking is a challenging problem to the defenders. Today, many different malware-analysis tools incur specific features against malwares but manual and error-prone. In this study, we proposed a behavior-based monitoring detection system to effectively deal native API hooks in user-mode. Unlike other malware identification techniques, our approach involved dynamically analyzing the behavior of native API call hooking malwares. Comparing our experimental evaluation results with existing tools show better performance with no false positive.

  5. Leakage of Oil Following Rupture of Pipeline P/15-4 to Hook of Holland

    NARCIS (Netherlands)

    Kranenburg, C.

    1983-01-01

    This report presents computational results concerning the buoyancy-driven leakage of oil resulting from a possible rupture of the planned pipeline P/15-4 to Hook of Holland. The computations were commissioned by R.J. Brown and Associates (Netherlands) b.v. (RJBA Job No. 7004.02). The specifications

  6. Expression and functional characterization of Xhmg-at-hook genes in Xenopus laevis.

    Directory of Open Access Journals (Sweden)

    Simone Macrì

    Full Text Available High Mobility Group A proteins (HMGA1 and HMGA2 are architectural nuclear factors involved in development, cell differentiation, and cancer formation and progression. Here we report the cloning, developmental expression and functional analysis of a new multi-AT-hook factor in Xenopus laevis (XHMG-AT-hook that exists in three different isoforms. Xhmg-at-hook1 and 3 isoforms, but not isoform 2, are expressed throughout the entire development of Xenopus, both in the maternal and zygotic phase. Localized transcripts are present in the animal pole in the early maternal phase; during the zygotic phase, mRNA can be detected in the developing central nervous system (CNS, including the eye, and in the neural crest. We show evidence that XHMG-AT-hook proteins differ from typical HMGA proteins in terms of their properties in DNA binding and in protein/protein interaction. Finally, we provide evidence that they are involved in early CNS development and in neural crest differentiation.

  7. Ensuring Privacy in the Android OS by Hooking Methods in Its API

    Directory of Open Access Journals (Sweden)

    Andrei Stefan Constantinescu

    2015-09-01

    Full Text Available The paper presents a mean to ensure security and privacy on Android devices available at the moment by applying a need to know principle for information that the installed applications can access. The presented method requires root access and an Open Source framework that allows hooking functions in the Android system, called Xposed, to be installed.

  8. Symposium of Hope: Recovery and Resiliency after the Sandy Hook Tragedy. Crisis Management

    Science.gov (United States)

    Zenere, Frank J.

    2013-01-01

    On February 27 and 28, 2013, The Symposium of Hope: Recovery and Resilience after the Sandy Hook Tragedy, was held in Danbury, Connecticut. The event was hosted by the United Way of Western Connecticut and Western Connecticut State University. Frank J. Zenere, school psychologist and crisis team member in the Division of Student Services of the…

  9. 78 FR 60018 - Requested Administrative Waiver of the Coastwise Trade Laws: Vessel HOOKED FOR REEL; Invitation...

    Science.gov (United States)

    2013-09-30

    ... association, business, labor union, etc.). You may review DOT's complete Privacy Act Statement in the Federal... TRANSPORTATION Maritime Administration Requested Administrative Waiver of the Coastwise Trade Laws: Vessel HOOKED... address the waiver criteria given in Sec. 388.4 of MARAD's regulations at 46 CFR part 388. Privacy...

  10. Radio continuum detection in blue early-type weak-emission-line galaxies

    Science.gov (United States)

    Paswan, A.; Omar, A.

    2016-06-01

    The star formation rates (SFRs) in weak-emission-line (WEL) galaxies in a volume-limited (0.02 Hz-1, respectively. The radio far-infrared correlation in four WEL galaxies suggests that the radio continuum emission from WEL galaxies is most likely a result of star formation activities. The median SFR for WEL galaxies is estimated as 0.23 ± 0.06 M⊙ yr-1, which is much less than SFRs (0.5-50 M⊙ yr-1) in purely star-forming blue ETGs. The SFRs in blue ETGs are found to be correlated with their stellar velocity dispersions (σ) and decreasing gradually beyond σ of ˜100 km s-1. This effect is most likely linked to the growth of a black hole and the suppression of star formation via active galactic nucleus (AGN) feedback. The colour differences between star-forming and WEL subtypes of blue ETGs appear to be driven to a large extent by the level of current star formation activities. In a likely scenario of an evolutionary sequence between subtypes, the observed colour distribution in blue ETGs can be explained best in terms of fast evolution through AGN feedback.

  11. Nonradial pulsations of hot evolved stars

    International Nuclear Information System (INIS)

    There are three classes of faint blue variable stars: the ZZ Ceti variables (DAV degenerate dwarfs), the DBV variables (DB degenerate dwarfs), and the GW Vir variables (DOV degenerate dwarfs). None of these classes of variable stars were known at the time of the last blue star meeting. Observational and theoretical studies of the ZZ Ceti variables, the DBV variables, and the GW Vir variables have shown them to be pulsating in nonradial g-modes. The cause of the pulsation has been determined for each class of variable star and, in all cases, also involves predictions of the stars envelope composition. The predictions are that the ZZ Ceti variables must have pure hydrogen surface layers, the DBV stars must have pure helium surface layers, and the GW Vir stars must have carbon and oxygen rich surface layers with less than 30% (by mass) of helium. Given these compositions, it is found that pulsation driving occurs as a result of the kappa and gamma effects operating in the partial ionization zones of either hydrogen or helium. In addition, a new driving mechanism, called convection blocking, also occurs in these variables. For the GW Vir variables, it is the kappa and gamma effects in the partial ionization regions of carbon and oxygen. 45 refs

  12. IN-SPIRALING CLUMPS IN BLUE COMPACT DWARF GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Elmegreen, Bruce G. [IBM Research Division, T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States); Zhang Hongxin; Hunter, Deidre A., E-mail: bge@watson.ibm.com [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)

    2012-03-10

    Giant star formation clumps in dwarf irregular galaxies can have masses exceeding a few percent of the galaxy mass enclosed inside their orbital radii. They can produce sufficient torques on dark matter halo particles, halo stars, and the surrounding disk to lose their angular momentum and spiral into the central region in 1 Gyr. Pairs of giant clumps with similarly large relative masses can interact and exchange angular momentum to the same degree. The result of this angular momentum loss is a growing central concentration of old stars, gas, and star formation that can produce a long-lived starburst in the inner region, identified with the blue compact dwarf (BCD) phase. This central concentration is proposed to be analogous to the bulge in a young spiral galaxy. Observations of star complexes in five local BCDs confirm the relatively large clump masses that are expected for this process. The observed clumps also seem to contain old field stars, even after background light subtraction, in which case the clumps may be long-lived. The two examples with clumps closest to the center have the largest relative clump masses and the greatest contributions from old stars. An additional indication that the dense central regions of BCDs are like bulges is the high ratio of the inner disk scale height to the scale length, which is comparable to 1 for four of the galaxies.

  13. Radio stars.

    Science.gov (United States)

    Hjellming, R M; Wade, C M

    1971-09-17

    Up to the present time six classes of radio stars have been established. The signals are almost always very faint and drastically variable. Hence their discovery has owed as much to serendipity as to the highly sophisticated equipment and techniques that have been used. When the variations are regular, as with the pulsars, this characteristic can be exploited very successfully in the search for new objects as well as in the detailed study of those that are already known. The detection of the most erratically variable radio stars, the flare stars and the x-ray stars, is primarily a matter of luck and patience. In the case of the novas, one at least knows where and oughly when to look for radio emission. A very sensitive interferometer is clearly the best instrument to use in the initial detection of a radio star. The fact that weak background sources are frequently present makes it essential to prove that the position of a radio source agrees with that of a star to within a few arc seconds. The potential of radio astronomy for the study of radio stars will not be realized until more powerful instruments than those that are available today can be utilized. So far, we have been able to see only the most luminous of the radio stars. PMID:17836594

  14. Star Imager

    DEFF Research Database (Denmark)

    Madsen, Peter Buch; Jørgensen, John Leif; Thuesen, Gøsta;

    1997-01-01

    The version of the star imager developed for Astrid II is described. All functions and features are described as well as the operations and the software protocol.......The version of the star imager developed for Astrid II is described. All functions and features are described as well as the operations and the software protocol....

  15. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star.......Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star....

  16. The growth of the central region by acquisition of counter-rotating gas in star-forming galaxies

    CERN Document Server

    Chen, Yan-Mei; Tremonti, Christy A; Bershady, Matt; Merrifield, Michael; Emsellem, Eric; Jin, Yi-Fei; Huang, Song; Fu, Hai; Wake, David A; Bundy, Kevin; Stark, David; Lin, Lihwai; Argudo-Fernandez, Maria; Bergmann, Thaisa Storchi; Bizyaev, Dmitry; Brownstein, Joel; Bureau, Martin; Chisholm, John; Drory, Niv; Guo, Qi; Hao, Lei; Hu, Jian; Li, Cheng; Li, Ran; Lopes, Alexandre Roman; Pan, Kai-Ke; Riffel, Rogemar A; Thomas, Daniel; Wang, Lan; Westfall, Kyle; Yan, Ren-Bin

    2016-01-01

    Galaxies grow through both internal and external processes. In about 10% of nearby red galaxies with little star formation, gas and stars are counter-rotating, demonstrating the importance of external gas acquisition in these galaxies. However, systematic studies of such phenomena in blue, star-forming galaxies are rare, leaving uncertain the role of external gas acquisition in driving evolution of blue galaxies. Based on new measurements with integral field spectroscopy of a large representative galaxy sample, we find an appreciable fraction of counter-rotators among blue galaxies (9 out of 489 galaxies). The central regions of blue counter-rotators show younger stellar populations and more intense, ongoing star formation than their outer parts, indicating ongoing growth of the central regions. The result offers observational evidence that the acquisition of external gas in blue galaxies is possible; the interaction with pre-existing gas funnels the gas into nuclear regions (< 1 kpc) to form new stars.

  17. Rose Prickles and Asparagus Spines--Different Hook Structures as Attachment Devices in Climbing Plants.

    Directory of Open Access Journals (Sweden)

    Friederike Gallenmüller

    Full Text Available Functional morphology and biomechanical properties of hook structures functioning as attachment devices in the leaning climbers Rosa arvensis, Rosa arvensis 'Splendens', Asparagus falcatus and Asparagus setaceus are analysed in order to investigate the variability in closely related species as well as convergent developments of hook structure and properties in distant systematic lineages (monocots and dicots. Prickles and spines were characterised by their size, orientation and the maximum force measured at failure in mechanical tests performed with traction forces applied at different angles. In Rosa arvensis and Rosa arvensis 'Splendens' three types of prickles differing largely in geometrical and mechanical properties are identified (prickles of the wild species and two types of prickles in the cultivar. In prickles of Rosa arvensis no particular orientation of the prickle tip is found whereas in the cultivar Rosa arvensis 'Splendens' prickles gradually gain a downward-orientation due to differential growth in the first weeks of their development. Differences in mechanical properties and modes of failure are correlated to geometrical parameters. In Asparagus falcatus and Asparagus setaceus spines are composed of leaf tissue, stem tissue and tissue of the axillary bud. Between species spines differ in size, orientation, distribution along the stem, tissue contributions and mechanical properties. The prickles of Rosa arvensis and its cultivar and the spines of the studied Asparagus species have several traits in common: (1 a gradual change of cell size and cell wall thickness, with larger cells in the centre and smaller thick-walled cells at the periphery of the hooks, (2 occurrence of a diversity of shape and geometry within one individual, (3 failure of single hooks when submitted to moderate mechanical stresses (Fmax/basal area < 35 N/mm² and (4 failure of the hooks without severe stem damage (at least in the tested wild species.

  18. Rose Prickles and Asparagus Spines--Different Hook Structures as Attachment Devices in Climbing Plants.

    Science.gov (United States)

    Gallenmüller, Friederike; Feus, Amélie; Fiedler, Kathrin; Speck, Thomas

    2015-01-01

    Functional morphology and biomechanical properties of hook structures functioning as attachment devices in the leaning climbers Rosa arvensis, Rosa arvensis 'Splendens', Asparagus falcatus and Asparagus setaceus are analysed in order to investigate the variability in closely related species as well as convergent developments of hook structure and properties in distant systematic lineages (monocots and dicots). Prickles and spines were characterised by their size, orientation and the maximum force measured at failure in mechanical tests performed with traction forces applied at different angles. In Rosa arvensis and Rosa arvensis 'Splendens' three types of prickles differing largely in geometrical and mechanical properties are identified (prickles of the wild species and two types of prickles in the cultivar). In prickles of Rosa arvensis no particular orientation of the prickle tip is found whereas in the cultivar Rosa arvensis 'Splendens' prickles gradually gain a downward-orientation due to differential growth in the first weeks of their development. Differences in mechanical properties and modes of failure are correlated to geometrical parameters. In Asparagus falcatus and Asparagus setaceus spines are composed of leaf tissue, stem tissue and tissue of the axillary bud. Between species spines differ in size, orientation, distribution along the stem, tissue contributions and mechanical properties. The prickles of Rosa arvensis and its cultivar and the spines of the studied Asparagus species have several traits in common: (1) a gradual change of cell size and cell wall thickness, with larger cells in the centre and smaller thick-walled cells at the periphery of the hooks, (2) occurrence of a diversity of shape and geometry within one individual, (3) failure of single hooks when submitted to moderate mechanical stresses (Fmax/basal area < 35 N/mm²) and (4) failure of the hooks without severe stem damage (at least in the tested wild species).

  19. Rose Prickles and Asparagus Spines--Different Hook Structures as Attachment Devices in Climbing Plants.

    Science.gov (United States)

    Gallenmüller, Friederike; Feus, Amélie; Fiedler, Kathrin; Speck, Thomas

    2015-01-01

    Functional morphology and biomechanical properties of hook structures functioning as attachment devices in the leaning climbers Rosa arvensis, Rosa arvensis 'Splendens', Asparagus falcatus and Asparagus setaceus are analysed in order to investigate the variability in closely related species as well as convergent developments of hook structure and properties in distant systematic lineages (monocots and dicots). Prickles and spines were characterised by their size, orientation and the maximum force measured at failure in mechanical tests performed with traction forces applied at different angles. In Rosa arvensis and Rosa arvensis 'Splendens' three types of prickles differing largely in geometrical and mechanical properties are identified (prickles of the wild species and two types of prickles in the cultivar). In prickles of Rosa arvensis no particular orientation of the prickle tip is found whereas in the cultivar Rosa arvensis 'Splendens' prickles gradually gain a downward-orientation due to differential growth in the first weeks of their development. Differences in mechanical properties and modes of failure are correlated to geometrical parameters. In Asparagus falcatus and Asparagus setaceus spines are composed of leaf tissue, stem tissue and tissue of the axillary bud. Between species spines differ in size, orientation, distribution along the stem, tissue contributions and mechanical properties. The prickles of Rosa arvensis and its cultivar and the spines of the studied Asparagus species have several traits in common: (1) a gradual change of cell size and cell wall thickness, with larger cells in the centre and smaller thick-walled cells at the periphery of the hooks, (2) occurrence of a diversity of shape and geometry within one individual, (3) failure of single hooks when submitted to moderate mechanical stresses (Fmax/basal area < 35 N/mm²) and (4) failure of the hooks without severe stem damage (at least in the tested wild species). PMID:26629690

  20. Estruturas fundamentais no blues

    OpenAIRE

    Silva, Rafael Palmeira da

    2012-01-01

    Resumo: Esta pesquisa tem como objeto de estudo a aplicação e adaptação da teoria de Schenker como ferramenta analítica aplicada ao jazz, tendo em vista a possibilidade de encontrar estruturas fundamentais distintas na música popular. Tendo como base as análises feitas por Larson (1998; 2009), Forte (2011) e Stock (1993) a pesquisa abordará, em um primeiro momento, as origens do jazz (blues e ragtime) como parte essencial para sua abordagem analítica, através da ótica etno-schenkeriana propos...

  1. SHP2 positively regulates TGFβ1-induced epithelial-mesenchymal transition modulated by its novel interacting protein Hook1.

    Science.gov (United States)

    Li, Shuomin; Wang, Linrun; Zhao, Qingwei; Liu, Yu; He, Lingjuan; Xu, Qinqin; Sun, Xu; Teng, Li; Cheng, Hongqiang; Ke, Yuehai

    2014-12-01

    The epithelial-mesenchymal transition (EMT) is an essential process for embryogenesis. It also plays a critical role in the initiation of tumor metastasis. Src homology 2 (SH2)-domain containing protein-tyrosine phosphatase-2 (SHP2) is a ubiquitously expressed protein-tyrosine phosphatase and is mutated in many tumors. However, its functional role in tumor metastasis remains largely unknown. We found that TGFβ1-induced EMT in lung epithelial A549 cells was partially blocked when SHP2 was decreased by transfected siRNA. The constitutively active form (E76V) promoted EMT while the phosphatase-dead mutation (C459S) and the SHP2 inhibitor PHPS1 blocked EMT, which further demonstrated that the phosphatase activity of SHP2 was required for promoting TGFβ1-induced EMT. Using the protein-tyrosine phosphatase domain of SHP2 as bait, we identified a novel SHP2-interacting protein Hook1. Hook1 was down-regulated during EMT in A549 cells. Overexpression of Hook1 inhibited EMT while knockdown of Hook1 promoted EMT. Moreover, both the protein-tyrosine phosphatase domain and N-terminal SH2 domain of SHP2 directly interacted with Hook1. Down-regulation of Hook1 increased SHP2 activity. These results suggested that Hook1 was an endogenous negative regulator of SHP2 phosphatase activity. Our data showed that the protein-tyrosine phosphatase SHP2 was involved in the process of EMT and Hook1 repressed EMT by regulating the activation of SHP2. SHP2-Hook1 complex may play important roles in tumor metastases by regulating EMT in cancer cells.

  2. Second Record Of Blue-Nosed Grubfish, Parapercis Albogutta(Günther, 1872 (Perciformes: Penguipedidae From Bitung,North Sulawesi.

    Directory of Open Access Journals (Sweden)

    Fasmi Achmad

    2009-04-01

    Full Text Available A specimens of Blue-nosed Grubfish, Parapercis alboguttata (Günther, 1872 were collected from reef flat of RonBolaan, Lembeh Island, North Sulawesi on 21 July 2008. It was caught by hook and line from a depths of about 10 - 20m. First record of this specimen found in Makassar Strait and deposited at the Bishop Museum (BPBM in Honolulu,USA. P. alboguttata has been found in many scattered locations in the Indo-West Pacific, from north western Australia,Indonesia, Philippines, Singapore, Malaysia, Oman and Somalia. Morphological features of the Indonesian specimenare reported.

  3. Blue ocean leadership.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2014-05-01

    Ten years ago, two INSEAD professors broke ground by introducing "blue ocean strategy," a new model for discovering uncontested markets that are ripe for growth. In this article, they apply their concepts and tools to what is perhaps the greatest challenge of leadership: closing the gulf between the potential and the realized talent and energy of employees. Research indicates that this gulf is vast: According to Gallup, 70% of workers are disengaged from their jobs. If companies could find a way to convert them into engaged employees, the results could be transformative. The trouble is, managers lack a clear understanding of what changes they could make to bring out the best in everyone. Here, Kim and Mauborgne offer a solution to that problem: a systematic approach to uncovering, at each level of the organization, which leadership acts and activities will inspire employees to give their all, and a process for getting managers throughout the company to start doing them. Blue ocean leadership works because the managers' "customers"-that is, the people managers oversee and report to-are involved in identifying what's effective and what isn't. Moreover, the approach doesn't require leaders to alter who they are, just to undertake a different set of tasks. And that kind of change is much easier to implement and track than changes to values and mind-sets. PMID:24956870

  4. Blue ocean leadership.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2014-05-01

    Ten years ago, two INSEAD professors broke ground by introducing "blue ocean strategy," a new model for discovering uncontested markets that are ripe for growth. In this article, they apply their concepts and tools to what is perhaps the greatest challenge of leadership: closing the gulf between the potential and the realized talent and energy of employees. Research indicates that this gulf is vast: According to Gallup, 70% of workers are disengaged from their jobs. If companies could find a way to convert them into engaged employees, the results could be transformative. The trouble is, managers lack a clear understanding of what changes they could make to bring out the best in everyone. Here, Kim and Mauborgne offer a solution to that problem: a systematic approach to uncovering, at each level of the organization, which leadership acts and activities will inspire employees to give their all, and a process for getting managers throughout the company to start doing them. Blue ocean leadership works because the managers' "customers"-that is, the people managers oversee and report to-are involved in identifying what's effective and what isn't. Moreover, the approach doesn't require leaders to alter who they are, just to undertake a different set of tasks. And that kind of change is much easier to implement and track than changes to values and mind-sets.

  5. Blue emitting undecaplatinum clusters

    Science.gov (United States)

    Chakraborty, Indranath; Bhuin, Radha Gobinda; Bhat, Shridevi; Pradeep, T.

    2014-07-01

    A blue luminescent 11-atom platinum cluster showing step-like optical features and the absence of plasmon absorption was synthesized. The cluster was purified using high performance liquid chromatography (HPLC). Electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS) suggest a composition, Pt11(BBS)8, which was confirmed by a range of other experimental tools. The cluster is highly stable and compatible with many organic solvents.A blue luminescent 11-atom platinum cluster showing step-like optical features and the absence of plasmon absorption was synthesized. The cluster was purified using high performance liquid chromatography (HPLC). Electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS) suggest a composition, Pt11(BBS)8, which was confirmed by a range of other experimental tools. The cluster is highly stable and compatible with many organic solvents. Electronic supplementary information (ESI) available: Details of experimental procedures, instrumentation, chromatogram of the crude cluster; SEM/EDAX, DLS, PXRD, TEM, FT-IR, and XPS of the isolated Pt11 cluster; UV/Vis, MALDI MS and SEM/EDAX of isolated 2 and 3; and 195Pt NMR of the K2PtCl6 standard. See DOI: 10.1039/c4nr02778g

  6. Postpartum Blues and Postpartum Depression

    Directory of Open Access Journals (Sweden)

    Erdem Ö et al.

    2009-09-01

    Full Text Available Postpartum blues which is seen during the postpartum period is a transient psychological state. Most of the mothers experience maternity blues in postpartum period. It remains usually unrecognized by the others. Some sensitive families can misattribute these feelings as depression. In this article, we tried to review the characteristics of maternity blues and its differences from depression. We defined depression and presented the incidence and diagnostic criteria, of major depression as well as the risk factors and clinic findings of postpartum depression. Thus, especially at primary care we aimed to prevent misdiagnosis of both maternity blues and depression

  7. Horndeski's Stars

    CERN Document Server

    Cisterna, Adolfo; Rinaldi, Massimiliano

    2015-01-01

    We consider the sector of Horndeski's gravity characterized by a coupling between the kinetic scalar field term and the Einstein tensor. Our goal is to find realistic neutron star configurations in this framework. We show that, in a certain limit, there exist solutions that are identical to the Schwarzschild metric outside the star but change considerably inside, where the scalar field is not trivial. We study numerically the equations and find the region of the parameter space where neutron stars exist. We determine their internal pressure and mass-radius relation, and we compare them with standard general relativity models.

  8. An interferometric view of binary stars

    CERN Document Server

    Boffin, Henri M J

    2016-01-01

    The study of binary stars is critical to apprehend many of the most interesting classes of stars. Moreover, quite often, the study of stars in binary systems is our only mean to constrain stellar properties, such as masses and radii. Unfortunately, a great fraction of the most interesting binaries are so compact that they can only be apprehended by high-resolution techniques, mostly by interferometry. I present some results highlighting the use of interferometry in the study of binary stars, from finding companions and deriving orbits, determining the mass and radius of stars, to studying mass transfer in symbiotic stars, and tackling luminous blue variables. In particular, I show how interferometric studies using the PIONIER instrument have allowed us to confirm a dichotomy within symbiotic stars, obtain masses of stars with a precision better than 1%, and help us find a new Eta Carinae-like system. I will also illustrate the benefits for the study of binary stars one would get from upgrading the VLT Interfe...

  9. What are the Luminous Compact Blue Galaxies?

    CERN Document Server

    Pisano, D J; Guzmán, R; Gallego, J Perez; Castander, F J; Gruel, N

    2007-01-01

    Luminous Compact Blue Galaxies (LCBGs) are common at z~1, contributing significantly to the total star formation rate density. By z~0, they are a factor of ten rarer. While we know that LCBGs evolve rapidly, we do not know what drives their evolution nor into what types of galaxies they evolve. We present the results of a single-dish HI survey of local LCBGs undertaken to address these questions. Our results indicate that LCBGs have M(HI) and M(DYN) consistent with low-mass spirals, but typically exhaust their gas reservoirs in less than 2 Gyr. Overall, the properties of LCBGs are consistent with them evolving into high-mass dwarf elliptical or dwarf irregular galaxies or low-mass, late-type spiral galaxies.

  10. A Sparkling Spray of Stars

    Science.gov (United States)

    2008-12-01

    The festive season has arrived for astronomers at the European Southern Observatory (ESO) in the form of this dramatic new image. It shows the swirling gas around the region known as NGC 2264 -- an area of sky that includes the sparkling blue baubles of the Christmas Tree star cluster. Omega Centauri ESO PR Photo 48/08 NGC 2264 and the Christmas Tree cluster NGC 2264 lies about 2600 light-years from Earth in the obscure constellation of Monoceros, the Unicorn, not far from the more familiar figure of Orion, the Hunter. The image shows a region of space about 30 light-years across. William Herschel discovered this fascinating object during his great sky surveys in the late 18th century. He first noticed the bright cluster in January 1784 and the brightest part of the visually more elusive smudge of the glowing gas clouds at Christmas nearly two years later. The cluster is very bright and can easily be seen with binoculars. With a small telescope (whose lenses will turn the view upside down) the stars resemble the glittering lights on a Christmas tree. The dazzling star at the top is even bright enough to be seen with the unaided eye. It is a massive multiple star system that only emerged from the dust and gas a few million years ago. As well as the cluster there are many interesting and curious structures in the gas and dust. At the bottom of the frame, the dark triangular feature is the evocative Cone Nebula, a region of molecular gas flooded by the harsh light of the brightest cluster members. The region to the right of the brightest star has a curious, fur-like texture that has led to the name Fox Fur Nebula. Much of the image appears red because the huge gas clouds are glowing under the intense ultra-violet light coming from the energetic hot young stars. The stars themselves appear blue as they are hotter, younger and more massive than our own Sun. Some of this blue light is scattered by dust, as can be seen occurring in the upper part of the image. This

  11. Bursts of star formation in computer simulations of dwarf galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Comins, N.F.

    1984-09-01

    A three-dimensional Stochastic Self-Propagating Star Formation (SSPSF) model of compact galacies is presented. Two phases of gas, active and inactive, are present, and permanent depletion of gas in the form of long lived, low mass stars and remnants occurs. Similarly, global infall of gas from a galactic halo or through galactic cannibalism is permitted. We base our parameters on the observed properties of the compact blue galaxy I Zw 36. Our results are that bursts of star formation occur much more frequently in these runs than continuous nonbursting star formation, suggesting that the blue compact galaxies are probably undergoing bursts rather than continuous, nonbursting low-level star formation activity.

  12. Star formation

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, P.R.

    1978-09-27

    Theoretical models of star formation are discussed beginning with the earliest stages and ending in the formation of rotating, self-gravitating disks or rings. First a model of the implosion of very diffuse gas clouds is presented which relies upon a shock at the edge of a galactic spiral arm to drive the implosion. Second, models are presented for the formation of a second generation of massive stars in such a cloud once a first generation has formed. These models rely on the ionizing radiation from massive stars or on the supernova shocks produced when these stars explode. Finally, calculations of the gravitational collapse of rotating clouds are discussed with special focus on the question of whether rotating disks or rings are the result of such a collapse. 65 references.

  13. Star formation

    International Nuclear Information System (INIS)

    Theoretical models of star formation are discussed beginning with the earliest stages and ending in the formation of rotating, self-gravitating disks or rings. First a model of the implosion of very diffuse gas clouds is presented which relies upon a shock at the edge of a galactic spiral arm to drive the implosion. Second, models are presented for the formation of a second generation of massive stars in such a cloud once a first generation has formed. These models rely on the ionizing radiation from massive stars or on the supernova shocks produced when these stars explode. Finally, calculations of the gravitational collapse of rotating clouds are discussed with special focus on the question of whether rotating disks or rings are the result of such a collapse. 65 references

  14. Carbon Stars

    Indian Academy of Sciences (India)

    T. Lloyd Evans

    2010-12-01

    In this paper, the present state of knowledge of the carbon stars is discussed. Particular attention is given to issues of classification, evolution, variability, populations in our own and other galaxies, and circumstellar material.

  15. Rock Stars

    Institute of Scientific and Technical Information of China (English)

    张国平

    2000-01-01

    Around the world young people are spending unbelievable sums of money to listen to rock music. Forbes Magazine reports that at least fifty rock stars have incomes between two million and six million dollars per year.

  16. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Frigaard, Peter

    Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star....

  17. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Andersen, Thomas Lykke

    Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star....

  18. Instant BlueStacks

    CERN Document Server

    Judge, Gary

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. A fast-paced, example-based approach guide for learning BlueStacks.This book is for anyone with a Mac or PC who wants to run Android apps on their computer. Whether you want to play games that are freely available for Android but not your computer, or you want to try apps before you install them on a physical device or use it as a development tool, this book will show you how. No previous experience is needed as this is written in plain English

  19. National Wildlife Refuge Visitor Survey 2010/2011 : Individual refuge results for Bombay Hook National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the National Wildlife Refuge Visitor Survey for Bombay Hook NWR and is part of the USGS Data Series 643. The survey was conducted to better...

  20. SPECTROSCOPIC ANALYSES OF MASSIVE BLUE STARS (GALACTIC OR EXTRAGALACTIC

    Directory of Open Access Journals (Sweden)

    A. Herrero

    2008-01-01

    Full Text Available Repasamos los recientes avances en nuestro conocimiento de las estrellas masivas a través del análisis de sus espectros. Discutimos brevemente las mejoras en los modelos de atmósfera y en los métodos de análisis. Se comparan los resultados obtenidos en estrellas del Grupo Local y se describe el estado actual de diferentes cuestiones que permanecen abiertas, como la escala de temperaturas de las estrellas OB, la Relación entre el Momento del Viento y la Luminosidad o la rotación estelar.

  1. Direct manipulation of intracellular stress fibres using a hook-shaped AFM probe

    Energy Technology Data Exchange (ETDEWEB)

    Machida, Shinichi; Watanabe-Nakayama, Takahiro; Harada, Ichiro; Afrin, Rehana [Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-S2-8, Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Nakayama, Tomonobu [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Ikai, Atsushi, E-mail: smachida@bio.titech.ac.jp [Innovation Laboratory, Tokyo Institute of Technology, 4259-S2-8, Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan)

    2010-09-24

    Atomic force microscopy (AFM) is a highly successful technique for imaging nanometre-sized samples and measuring pico- to nano-newton forces acting between atoms and molecules. When it comes to the manipulation of larger samples with forces of tens and hundreds of nano-newtons, however, the present chemistry-based modification protocols for functionalizing AFM cantilevers to achieve the formation of covalent/non-covalent linkages between the AFM probe and the sample surface do not produce strong enough bonds. For the purpose of measuring the fracture strength and other mechanical properties of stress fibres (SFs) in living as well as semi-intact fibroblast cells, we fabricated an AFM probe with a hooking function by focused ion beam technology and used the AFM probe hook to capture, pull and eventually sever a chosen SF labelled with green or red fluorescent protein.

  2. Hooked on the nicotine addiction thesis: a response to DiFranza.

    Science.gov (United States)

    Dar, Reuven; Frenk, Hanan

    2013-11-18

    DiFranza's rebuttal to our critique of the "Hooked on Nicotine" research program misconstrues our arguments beyond recognition. The grossest misrepresentation of our critique by DiFranza is that we devise (by thwarting science) to rescue "the conventional wisdom" of the "threshold model of nicotine addiction." In fact, the difference between our positions lies elsewhere: We believe that nicotine is not an addictive drug and that its contribution to the smoking habit is secondary; DiFranza believes that nicotine is so powerfully addictive that novice smokers can lose autonomy over their smoking behavior after one cigarette or even following a single puff. Our review aimed to critically examine the empirical basis of this extreme version of the nicotine "addiction" model. In this brief commentary we illustrate how the commitment to the nicotine "addiction" theory has biased the methodology and the interpretation of the data in "Hooked on Nicotine" research program.

  3. The evolutionary status of the UX Orionis star RZ Piscium

    CERN Document Server

    Grinin, V P; Musaev, F A; 10.1051/0004-6361/201014889

    2011-01-01

    The star RZ Psc is one of the most enigmatic members of the UX Ori star family. It shows all properties that are typical for these stars (the light variability, high linear polarization in deep minima, the blueing effect) except for one: it lacks any signatures of youth. With the Li I line, as a rough estimate for the stellar age, we show that the "lithium" age of RZ Psc lies between the age of stars in the Pleiades (approximately 70 Myr) and the Orion (approximately 10 Myr) clusters. We also roughly estimated the age of RZ Psc based on the proper motion of the star using the Tycho-2 catalog. We found that the star has escaped from its assumed birthplace near to the Galactic plane about 30-40 Myr ago. We conclude that RZ Psc is a post-UXOr star, and its sporadic eclipses are caused by material from the debris disk.

  4. Stars Just Got Bigger - A 300 Solar Mass Star Uncovered

    Science.gov (United States)

    2010-07-01

    raises the challenge to theorists still further. "Either they were born so big or smaller stars merged together to produce them," explains Crowther. Stars between about 8 and 150 solar masses explode at the end of their short lives as supernovae, leaving behind exotic remnants, either neutron stars or black holes. Having now established the existence of stars weighing between 150 and 300 solar masses, the astronomers' findings raise the prospect of the existence of exceptionally bright, "pair instability supernovae" that completely blow themselves apart, failing to leave behind any remnant and dispersing up to ten solar masses of iron into their surroundings. A few candidates for such explosions have already been proposed in recent years. Not only is R136a1 the most massive star ever found, but it also has the highest luminosity too, close to 10 million times greater than the Sun. "Owing to the rarity of these monsters, I think it is unlikely that this new record will be broken any time soon," concludes Crowther. Notes [1] The star A1 in NGC 3603 is a double star, with an orbital period of 3.77 days. The two stars in the system have, respectively, 120 and 92 times the mass of the Sun, which means that they have formed as stars weighing, respectively, 148 and 106 solar masses. [2] The team used the SINFONI, ISAAC and MAD instruments, all attached to ESO's Very Large Telescope at Paranal, Chile. [3] (note added on 26 July 2010) The "bigger" in the title does not imply that these stars are the biggest observed. Such stars, called red supergiants, can have radii up to about a thousand solar radii, while R136a1, which is blue, is about 35 times as large as the Sun. However, R136a1 is the star with the greatest mass known to date. More information This work is presented in an article published in the Monthly Notices of the Royal Astronomical Society ("The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 Msun stellar mass limit", by

  5. Chemical and anti-ulcer evaluation of Jodina rhombifolia (Hook. & Arn.) Reissek extracts

    OpenAIRE

    Jarbas A. Montanha; Eloir P. Schenkel; Alexandre T. Cardoso-Taketa; Ana P. Dresch; Augusto Langeloh; Eliane Dallegrave

    2009-01-01

    Jodina rhombifolia (Hook. & Arn.) Reissek (Santalaceae) is a medicinal plant popularly used as an anti-ulcer medicine. The plant native from Southern Brazil was chemically investigated and tested for its in vivo gastric anti-ulcer property by chloride acid/ethanol model. The chromatographic analysis of the hydroethanol extract of its leaves revealed the presence of C-glycosylflavonoids. From the n-butanol fraction of the hydroethanol extract of its aerial parts, vicenin-2 was isolated as the ...

  6. Tinospora crispa (L.) Hook. f. & Thomson: A Review of Its Ethnobotanical, Phytochemical, and Pharmacological Aspects

    OpenAIRE

    Ahmad, Waqas; Jantan, Ibrahim; Bukhari, Syed N. A.

    2016-01-01

    Tinospora crispa (L.) Hook. f. & Thomson (Menispermaceae), found in the rainforests or mixed deciduous forests in Asia and Africa, is used in traditional medicines to treat numerous health conditions. This review summarizes the up-to-date reports about the ethnobotany, phytochemistry, pharmacological activities, toxicology, and clinical trials of the plant. It also provides critical assessment about the present knowledge of the plant which could contribute toward improving its prospect as a s...

  7. Tinospora crispa (L.) Hook. f. & Thomson: A review of its ethnobotanical, phytochemical and pharmacological aspects

    OpenAIRE

    Ibrahim eJantan; Waqas eAhmad; SYED NASIR ABBAS eBUKHARI

    2016-01-01

    Tinospora crispa (L.) Hook. f. & Thomson (Menispermaceae), found in the rainforests or mixed deciduous forests in Asia and Africa, is used in traditional medicines to treat numerous health conditions. This review summarizes the up-to-date reports about the ethnobotany, phytochemistry, pharmacological activities, toxicology and clinical trials of the plant. It also provides critical assessment about the present knowledge of the plant which could contribute towards improving its prospect as a ...

  8. Fruit and seed discoveries in Stichoneuron membranaceum Hook. f. (Stemonaceae: an endemic to Indo-Myanmar

    Directory of Open Access Journals (Sweden)

    Koushik Majumdar

    2013-04-01

    Full Text Available Stichoneuron membranaceum Hook. f. is an endemic species of Indo-Myanmar hotspot whose fruit and seed remained unknown to science since 1850, until they were collected from Tripura, Northeast India. Based on these gatherings, this study is the first report about the development and morphological features of fruit and seed. Earlier historical collections of this species were discussed. Its preferred habitat, possible pollinating agents and seed dispersal mechanism were also investigated.

  9. A viral suppressor protein inhibits host RNA silencing by hooking up with Argonautes

    OpenAIRE

    Jin, Hailing; Zhu, Jian-Kang

    2010-01-01

    RNA viruses are particularly vulnerable to RNAi-based defenses in the host, and thus have evolved specific proteins, known as viral suppressors of RNA silencing (VSRs), as a counterdefense. In this issue of Genes & Development, Azevedo and colleagues (pp. 904–915) discovered that P38, the VSR of Turnip crinkle virus, uses its glycine/tryptophane (GW) motifs as an ARGONAUTE (AGO) hook to attract and disarm the host's essential effector of RNA silencing. Several GW motif-containing cellular pro...

  10. PHARMACOGNOSTIC AND ANATOMICAL STUDIES OF ANTIGONON LEPTOPUS HOOK. AND ARN.: A PROMISING MEDICINAL CLIMBER

    OpenAIRE

    Rahaman Chowdhury Habibur; Saha Sathi

    2013-01-01

    The evaluation of quality and purity of crude drugs by means of various parameters is the most important aspect of pharmacognosy. The present study deals with pharmacognostic characterization of Antigonon leptopus Hook. and Arn. of the family Polygonaceae. The tubers of it are used by the tribal people as tonic and nutritious food. The parameters like micromorphological, anatomical, phytochemical and physical constants have been employed for the pharmacognostical evaluation of different parts...

  11. Exposure of the mitral valve using flexible self-retaining retractors and an atrial hook.

    Science.gov (United States)

    Shibata, Toshihiko; Yasuoka, Takashi; Inoue, Kazushige; Ikuta, Takeshi; Bito, Yasuyuki

    2007-10-01

    We hereby present our technique for using the self-retaining flexible arm retractor and its attachments for mitral valve exposure. The Aortic Valve Assistant, which was developed for aortic valve exposure, is also very useful for exposure of the inferior wall of the left atrium. Our modified atrial hook provides excellent exposure of the anterior mitral annulus. Extensive dissection and the combined use of the flexible arm and attachments allows us comfortable access for mitral valve operations.

  12. Blue straggler formation at core collapse

    CERN Document Server

    Banerjee, Sambaran

    2016-01-01

    Among the most striking feature of blue straggler stars (BSS) is the presence of multiple sequences of BSSs in the colour-magnitude diagrams (CMDs) of several globular clusters. It is often envisaged that such a multiple BSS sequence would arise due a recent core collapse of the host cluster, triggering a number of stellar collisions and binary mass transfers simultaneously over a brief episode of time. Here we examine this scenario using direct N-body computations of moderately massive star clusters (of order 10^4 Msun ). As a preliminary attempt, these models are initiated with approx. 8-10 Gyr old stellar population and King profiles of high concentrations, being "tuned" to undergo core collapse quickly. BSSs are indeed found to form in a "burst" at the onset of the core collapse and several of such BS-bursts occur during the post-core-collapse phase. In those models that include a few percent primordial binaries, both collisional and binary BSSs form after the onset of the (near) core-collapse. However, t...

  13. Blue Stragglers in Clusters and Integrated Spectral Properties of Stellar Populations

    CERN Document Server

    Xin, Yu

    2014-01-01

    Blue straggler stars are the most prominent bright objects in the colour-magnitude diagram of a star cluster that challenges the theory of stellar evolution. Star clusters are the closest counterparts of the theoretical concept of simple stellar populations (SSPs) in the Universe. SSPs are widely used as the basic building blocks to interpret stellar contents in galaxies. The concept of an SSP is a group of coeval stars which follows a given distribution in mass, and has the same chemical property and age. In practice, SSPs are more conveniently made by the latest stellar evolutionary models of single stars. In reality, however, stars can be more complicated than just single either at birth time or during the course of evolution in a typical environment. Observations of star clusters show that there are always exotic objects which do not follow the predictions of standard theory of stellar evolution. Blue straggler stars (BSSs), as discussed intensively in this book both observationally and theoretically, are...

  14. Luminous Blue Variables are Antisocial: Their Isolation Implies they are Kicked Mass Gainers in Binary Evolution

    Science.gov (United States)

    Tombleson, Ryan; Smith, Nathan

    2015-01-01

    Based on their relatively isolated environments, we argue that luminous blue variables (LBVs) must be primarily the product of binary evolution, challenging the traditional single-star view wherein LBVs mark a brief transition between massive O-type stars and Wolf-Rayet (WR) stars. If the latter were true, then LBVs should be concentrated in young massive clusters like early O-type stars. This is decidedly not the case. Examining locations of LBVs in our Galaxy and the Magellanic Clouds reveals that, with few exceptions, LBVs systematically avoid clusters of O-type stars. In the Large Magellanic Cloud, LBVs are statistically much more isolated than O-type stars, and (perhaps most surprisingly) even more isolated than WR stars. This makes it impossible for LBVs to be single 'massive stars in transition' to WR stars. Instead, we propose that massive stars and supernova (SN) subtypes are dominated by bifurcated evolutionary paths in interacting binaries, wherein most WR stars and SNe Ibc correspond to the mass donors, while LBVs (and their lower-mass analogs like B[e] supergiants, which are even more isolated) are the mass gainers. In this view, LBVs are evolved massive blue stragglers. Through binary mass transfer, rejuvinated mass gainers get enriched, spun up, and sometimes kicked far from their clustered birthsites by their companion's SN. This scenario agrees better with LBVs exploding as Type IIn SNe in isolation, and it predicts that many massive runaway stars may be rapid rotators. Mergers or Thorne-Zykow objects might also give rise to LBVs, but these scenarios may have a harder time explaining why LBVs avoid clusters.

  15. Indications of Inflow Motions in Regions Forming Massive Stars

    CERN Document Server

    Wu, J

    2003-01-01

    Observational evidence for inflowing motions in massive star forming regions has been extremely rare. We have made a spectroscopic survey of a sample of 28 massive star forming cores associated with water masers. An optically thick line of HCN (3-2) was used in combination with optically thin lines [H^{13}CN (3-2) or C^{34}S (5-4), (3-2), and (2-1)], to identify ``blue'' line profiles that can indicate inflow. Comparing intensities for 18 double-peaked line profiles yields 11 blue and 3 red profiles that are statistically significant. In the full sample of 28 sources, 12 show blue profiles and 6 show red profiles that are statistically significant based on the velocity offsets of lines that are optically thick from those that are optically thin. These results indicate that HCN (3-2) emission may trace inflow in regions forming high-mass stars.

  16. NoSOCS in SDSS - V. Red disc and blue bulge galaxies across different environments

    Science.gov (United States)

    Lopes, P. A. A.; Rembold, S. B.; Ribeiro, A. L. B.; Nascimento, R. S.; Vajgel, B.

    2016-09-01

    We investigated the typical environment and physical properties of `red discs' and `blue bulges', comparing those to the `normal' objects in the blue cloud and red sequence. Our sample is composed of cluster members and field galaxies at z ≤ 0.1, so that we can assess the impact of the local and global environment. We find that disc galaxies display a strong dependence on environment, becoming redder for higher densities. This effect is more pronounced for objects within the virial radius, being also strong related to the stellar mass. We find that local and global environment affect galaxy properties, but the most effective parameter is stellar mass. We find evidence for a scenario where `blue discs' are transformed into `red discs' as they grow in mass and move to the inner parts of clusters. From the metallicity differences of red and blue discs, and the analysis of their star formation histories, we suggest the quenching process is slow. We estimate a quenching time-scale of ˜2-3 Gyr. We also find from the sSFR-M* plane that `red discs' gradually change as they move into clusters. The `blue bulges' have many similar properties than `blue discs', but some of the former show strong signs of asymmetry. The high asymmetry `blue bulges' display enhanced recent star formation compared to their regular counterparts. That indicates some of these systems may have increased their star formation due to mergers. None the less, there may not be a single evolutionary path for these blue early-type objects.

  17. Blue-sky thinking

    International Nuclear Information System (INIS)

    Global environmental problems - such as the greenhouse effect, the depletion of natural resources and the accumulation of wastes - have been recognized as common international issues affecting humanity since the 1990s. Sustainable development on a global scale is now sought, for instance, with the establishment of the targets for greenhouse gas reduction in the 1997 Kyoto Protocol, and with the adoption of the Declaration on Sustainable Development at the 2002 Johannesburg Summit. Honda launched the slogan 'Blue Sky for Children' in the 1960s when environmental pollution became a highly visible issue. During that decade we started an aggressive approach aimed at substantial environmental improvement, and unveiled the Compound Vortex Controlled Combustion (CVCC) engine - which used unique low-emission technology - in the United States and Japan. Since then, we have developed the Variable Valve Timing and Lift Electric Control System (VTEC) and the i-VTEC series with innovative engine technology, permitting global production of vehicles that combine high performance with state-of-the-art low-emission technologies. And we continued to work to preserve the global environment by releasing a hybrid vehicle, the Insight, which achieved the most efficient fuel consumption in the world at the time of its introduction in 1998

  18. Blue Man袭东京

    Institute of Scientific and Technical Information of China (English)

    Naomi Saeki; 李宝怡

    2008-01-01

    <正>20年前在美国曼克顿风靡一时的Blue Man Group,最近在东京出现,马上成为城中话题。在东京,每年有不少舞台剧演出,但是像Blue Man Group这样备受注目的,近年罕见。Blue Man Group in Tokyo于上年12月开始公演·1个月的门票早在9月中旬

  19. Blue Angel for green electronics

    Energy Technology Data Exchange (ETDEWEB)

    Boettcher-Tiedemann, C.; Jacobs, B. [Federal Environmental Agency, Berlin (Germany)

    2004-07-01

    The Blue Angel was the first eco-label worldwide. It has been in existence for 26 years. For the last 12 years, modern electronic office and communications equipment has been among the products that are eligible for award of the Blue Angel. The Blue Angel eco-label is an important element of integrated product policy and is aimed towards environmentally sound product design. In addition, health aspects are increasingly being taken into account in criteria development. The use of the label gives innovative companies better market opportunities for products so labelled. For consumers and for purchasers in businesses and public administrations, it gives valuable guidance for product purchase. (orig.)

  20. The hot Gamma-Doradus and Maia stars

    CERN Document Server

    Balona, L A; Joshi, Yogesh C; Joshi, S; Sharma, K; Semenko, E; Pandey, G; Chakradhari, N K; Mkrtichian, David; Hema, B P; Nemec, J M

    2016-01-01

    The hot $\\gamma$~Doradus stars have multiple low frequencies characteristic of $\\gamma$~Dor or SPB variables, but are located between the red edge of the SPB and the blue edge of the $\\gamma$~Dor instability strips where all low-frequency modes are stable in current models of these stars. Though $\\delta$~Sct stars also have low frequencies, there is no sign of high frequencies in hot $\\gamma$~Dor stars. We obtained spectra to refine the locations of some of these stars in the H-R diagram and conclude that these are, indeed, anomalous pulsating stars. The Maia variables have multiple high frequencies characteristic of $\\beta$~Cep and $\\delta$~Sct stars, but lie between the red edge of the $\\beta$~Cep and the blue edge of the $\\delta$~Sct instability strips. We compile a list of all Maia candidates and obtain spectra of two of these stars. Again, it seems likely that these are anomalous pulsating stars which are currently not understood.

  1. The advanced stages of stellar evolution: impact of mass loss, rotation, and link with B[e] stars

    CERN Document Server

    Georgy, Cyril; Ekström, Sylvia; Meynet, Georges

    2016-01-01

    In this paper, we discuss some consequences of rotation and mass loss on the evolved stages of massive star evolution. The physical reasons of the time evolution of the surface velocity are explained, and then we show how the late-time evolution of massive stars are impacted in combination with the effects of mass loss. The most interesting result is that in some cases, a massive star can have a blue-red-blue evolution, opening the possibility that Blue Supergiants are composed by two distinct populations of stars: one just leaving the main sequence and crossing the HRD for the first time, and the other one evolving back to the blue side of the HRD after a Red Supergiant phase. We discuss a few possible observational tests that can allow to distinguish these two populations, and how supergiant B[e] stars fit in this context.

  2. Rainbow's Stars

    CERN Document Server

    Garattini, Remo

    2016-01-01

    In recent years, a growing interest on the equilibrium of compact astrophysical objects like white dwarf and neutron stars has been manifested. In particular, various modifications due to Planck scale energy effects have been considered. In this paper we analyze the modification induced by Gravity's Rainbow on the equilibrium configurations described by the Tolman-Oppenheimer-Volkoff (TOV) equation. Our purpose is to explore the possibility that the Rainbow Planck-scale deformation of space-time could support the existence of different compact stars.

  3. MN112: a new Galactic candidate Luminous Blue Variable

    CERN Document Server

    Gvaramadze, V V; Fabrika, S; Sholukhova, O; Berdnikov, L N; Cherepashchuk, A M; Zharova, A V

    2009-01-01

    We report the discovery of a new Galactic candidate Luminous Blue Variable (cLBV) via detection of an infrared circular nebula and follow-up spectroscopy of its central star. The nebula, MN112, is one of many dozens of circular nebulae detected at 24 $\\mu$m the Spitzer Space Telescope archival data, whose morphology is similar to that of nebulae associated with known (c)LBVs and related evolved massive stars. Specifically, the core-halo morphology of MN112 bears a striking resemblance to the circumstellar nebula associated with the Galactic cLBV GAL 079.29+00.46, which suggests that both nebulae might have a similar origin and that the central star of MN112 is a LBV. The spectroscopy of the central star showed that its spectrum is almost identical to that of the bona fide LBV P Cygni, which also supports the LBV classification of the object. To further constrain the nature of MN112, we searched for signatures of possible high-amplitude ($\\ga 1$ mag) photometric variability of the central star using archival a...

  4. Karner Blue Butterfly Recovery Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This recovery plan has been prepared by the Karner Blue Butterfly Recovery Team under the leadership of Dr. David Andow, University of Minnesota-St. Paul. Dr. John...

  5. China Mobile: Expanding "Blue Ocean"

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Driving force is crucial for realizing high-speed growth. The strong driving force from "Blue Ocean Strategy" is an important advantage for China Mobile to realize harmonious and leap-forward development.

  6. Star Product and Applications

    OpenAIRE

    Iida, Mari; Yoshioka, Akira

    2011-01-01

    A family of star products parametrized by complex matrices is defined. Especially commutative associative star products are treated, and star exponentials with respect to these star products are considered. Jacobi's theta functions are given as infinite sums of star exponentials. As application, several concrete identities are obtained by properties of the star exponentials.

  7. Stars Underground

    CERN Multimedia

    Jean Leyder

    1996-01-01

    An imaginary voyage in time where we were witness of the birth of the universe itself, the time of the Big-Bang 15 billion years ago. Particules from the very first moments of time : protons, neutrons and electrons, and also much more energetic one. These particules are preparing to interact collider and generating others which will be the birth to the stars ........

  8. Pulsating stars

    CERN Document Server

    Catelan, M?rcio

    2014-01-01

    The most recent and comprehensive book on pulsating stars which ties the observations to our present understanding of stellar pulsation and evolution theory.  Written by experienced researchers and authors in the field, this book includes the latest observational results and is valuable reading for astronomers, graduate students, nuclear physicists and high energy physicists.

  9. Blue Ocean vs. Five Forces

    OpenAIRE

    Burke, Andrew; Stel, André; Thurik, Roy

    2010-01-01

    textabstractThe article reports on the authors' research in the Netherlands which focused on a profit model in Dutch retail stores and a so-called blue-ocean approach which requires a new market that attracts consumers and increases profits. Topics include the competitive strategy approach to increasing profits. The authors conclude that the blue-ocean strategy or innovation approach is sustainable.

  10. Space-time modelling of lightning-caused ignitions in the Blue Mountains, Oregon

    Science.gov (United States)

    Diaz-Avalos, Carlos; Peterson, D.L.; Alvarado, Ernesto; Ferguson, Sue A.; Besag, Julian E.

    2001-01-01

    Generalized linear mixed models (GLMM) were used to study the effect of vegetation cover, elevation, slope, and precipitation on the probability of ignition in the Blue Mountains, Oregon, and to estimate the probability of ignition occurrence at different locations in space and in time. Data on starting location of lightning-caused ignitions in the Blue Mountains between April 1986 and September 1993 constituted the base for the analysis. The study area was divided into a pixela??time array. For each pixela??time location we associated a value of 1 if at least one ignition occurred and 0 otherwise. Covariate information for each pixel was obtained using a geographic information system. The GLMMs were fitted in a Bayesian framework. Higher ignition probabilities were associated with the following cover types: subalpine herbaceous, alpine tundra, lodgepole pine (Pinus contorta Dougl. ex Loud.), whitebark pine (Pinus albicaulis Engelm.), Engelmann spruce (Picea engelmannii Parry ex Engelm.), subalpine fir (Abies lasiocarpa (Hook.) Nutt.), and grand fir (Abies grandis (Dougl.) Lindl.). Within each vegetation type, higher ignition probabilities occurred at lower elevations. Additionally, ignition probabilities are lower in the northern and southern extremes of the Blue Mountains. The GLMM procedure used here is suitable for analysing ignition occurrence in other forested regions where probabilities of ignition are highly variable because of a spatially complex biophysical environment.

  11. Luminous blue variables are antisocial: their isolation implies that they are kicked mass gainers in binary evolution

    Science.gov (United States)

    Smith, Nathan; Tombleson, Ryan

    2015-02-01

    Based on their relatively isolated environments, we argue that luminous blue variables (LBVs) must be primarily the product of binary evolution, challenging the traditional single-star view wherein LBVs mark a brief transition between massive O-type stars and Wolf-Rayet (WR) stars. If the latter were true, then LBVs should be concentrated in young massive clusters like early O-type stars. This is decidedly not the case. Examining locations of LBVs in our Galaxy and the Magellanic Clouds reveals that, with only a few exceptions, LBVs systematically avoid clusters of O-type stars. In the Large Magellanic Cloud, LBVs are statistically much more isolated than O-type stars, and (perhaps most surprisingly) even more isolated than WR stars. This makes it impossible for LBVs to be single `massive stars in transition' to WR stars. Instead, we propose that massive stars and supernova (SN) subtypes are dominated by bifurcated evolutionary paths in interacting binaries, wherein most WR stars and Type Ibc supernovae (SNe Ibc) correspond to the mass donors, while LBVs (and their lower mass analogues like B[e] supergiants, which are even more isolated) are the mass gainers. In this view, LBVs are evolved massive blue stragglers. Through binary mass transfer, rejuvinated mass gainers get enriched, spun up, and sometimes kicked far from their clustered birth sites by their companion's SN. This scenario agrees better with LBVs exploding as SNe IIn in isolation, and it predicts that many massive runaway stars may be rapid rotators. Mergers or blue Thorne-Zytkow-like objects might also give rise to LBVs, but these scenarios may have a harder time explaining why LBVs avoid clusters.

  12. The Stars behind the Curtain

    Science.gov (United States)

    2010-02-01

    ESO is releasing a magnificent VLT image of the giant stellar nursery surrounding NGC 3603, in which stars are continuously being born. Embedded in this scenic nebula is one of the most luminous and most compact clusters of young, massive stars in our Milky Way, which therefore serves as an excellent "local" analogue of very active star-forming regions in other galaxies. The cluster also hosts the most massive star to be "weighed" so far. NGC 3603 is a starburst region: a cosmic factory where stars form frantically from the nebula's extended clouds of gas and dust. Located 22 000 light-years away from the Sun, it is the closest region of this kind known in our galaxy, providing astronomers with a local test bed for studying intense star formation processes, very common in other galaxies, but hard to observe in detail because of their great distance from us. The nebula owes its shape to the intense light and winds coming from the young, massive stars which lift the curtains of gas and clouds revealing a multitude of glowing suns. The central cluster of stars inside NGC 3603 harbours thousands of stars of all sorts (eso9946): the majority have masses similar to or less than that of our Sun, but most spectacular are several of the very massive stars that are close to the end of their lives. Several blue supergiant stars crowd into a volume of less than a cubic light-year, along with three so-called Wolf-Rayet stars - extremely bright and massive stars that are ejecting vast amounts of material before finishing off in glorious explosions known as supernovae. Using another recent set of observations performed with the SINFONI instrument on ESO's Very Large Telescope (VLT), astronomers have confirmed that one of these stars is about 120 times more massive than our Sun, standing out as the most massive star known so far in the Milky Way [1]. The clouds of NGC 3603 provide us with a family picture of stars in different stages of their life, with gaseous structures that are

  13. Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way

    International Nuclear Information System (INIS)

    In this paper the fundamental properties of the brightest known stars in our Galaxy are determined for future comparison with results for the most luminous stars in other galaxies. The H-R diagrams (M/sub v/ versus spectral type and M/sub bol/ versus log T/sub e/), the luminosities of the brightest stars, and the ratios of blue to red supergiants are all discussed, and a catalog of over 1000 supergiants and O stars in associations and clusters is included at the end of the paper.The ''theoretical'' H-R diagram (M/sub bol/ versus log T/sub e/) reveals a group of superluminous O stars with M/sub bol/ between -12 mag, a lack of evolved supergiants at these very high luminosities, and an apparent upper limit to the luminosities of the later-type supergiants (>B5) near M/sub bol/=-9.5 mag.The most luminous red supergiants have a maximum visual luminosity near M/sub v/approx. =-8 mag, supporting the suggestion by Sandage and Tammann that they are good distance indicators. Excluding the superluminous star Cyg OB 2 No. 12 (M/sub v/approx. =-9.9 mag), the brightest blue stars are found at M/sub v/approx. =-8.5 mag.The variation of the ratio of blue to red supergiants with luminosity is discussed. There is also evidence for a gradient in this ratio with distance from the galactic center, although the results are limited by the incompleteness of the data

  14. EAARL Coastal Topography-Sandy Hook Unit, Gateway National Recreation Area, New Jersey, Post-Nor'Ida, 2009

    Science.gov (United States)

    Nayegandhi, Amar; Vivekanandan, Saisudha; Brock, J.C.; Wright, C.W.; Bonisteel-Cormier, J.M.; Nagle, D.B.; Klipp, E.S.; Stevens, Sara

    2010-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived bare-earth (BE) and first-surface (FS) topography datasets were produced collaboratively by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL, and the National Park Service (NPS), Northeast Coastal and Barrier Network, Kingston, RI. This project provides highly detailed and accurate datasets of a portion of the Sandy Hook Unit of Gateway National Recreation Area in New Jersey, acquired post-Nor'Ida (November 2009 nor'easter) on December 4, 2009. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine aircraft, but the instrument was deployed on a Pilatus PC-6. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then

  15. Observational Constraints on Red and Blue Helium Burning Sequences

    CERN Document Server

    McQuinn, Kristen B W; Dalcanton, Julianne J; Dolphin, Andrew E; Holtzman, Jon; Weisz, Daniel R; Williams, Benjamin F

    2011-01-01

    We derive the optical luminosity, colors, and ratios of the blue and red helium burning (HeB) stellar populations from archival Hubble Space Telescope observations of nineteen starburst dwarf galaxies and compare them with theoretical isochrones from Padova stellar evolution models across metallicities from Z=0.001 to 0.009. We find that the observational data and the theoretical isochrones for both blue and red HeB populations overlap in optical luminosities and colors and the observed and predicted blue to red HeB ratios agree for stars older than 50 Myr over the time bins studied. These findings confirm the usefulness of applying isochrones to interpret observations of HeB populations. However, there are significant differences, especially for the red HeB population. Specifically we find: (1) offsets in color between the observations and theoretical isochrones of order 0.15 mag (0.5 mag) for the blue (red) HeB populations brighter than M_V ~ -4 mag, which cannot be solely due to differential extinction; (2...

  16. The Nebula around the Luminous Blue Variable WRAY 15-751 as seen by Herschel

    Science.gov (United States)

    Vamvatira-Nakou, C.; Hutsemekers, D.; Royer, P.; Naze, Y.; Magain, P.; Exter, K.; Waelkens, C.; Groenewegen, M.

    2013-06-01

    To understand the evolution of massive stars it is crucial to study the nebulae associated to Luminous Blue Variables which can reveal the star mass-loss history. We obtained far-infrared Herschel PACS imaging and spectroscopic observations of the nebula associated with the Luminous Blue Variable star WRAY 15-751. These images revealed a second nebula, bigger and cooler, lying in an empty cavity that probably delineates the remnant of the O-star bubble formed when the star was on the Main Sequence. The dust mass and temperature were derived from the modeling of the far-infrared SED. The analysis of the emission line spectrum revealed that the main nebula consists of a region of photoionised gas surrounded by a thin photodissociation region. Both regions are mixed with dust. The calculated C, N, O abundances, together with the estimated mass-loss rate, show that the nebula was ejected from the star during a Red Supergiant phase. This is compatible with the latest evolutionary tracks for a ~40 Mo star with little rotation.

  17. Cold Gas in Blue-Sequence E/S0s: Galaxies in Transition

    CERN Document Server

    Wei, Lisa H; Vogel, Stuart N; Baker, Andrew J

    2009-01-01

    We examine the HI+H_2 content of blue-sequence E/S0s -- a recently identified population of galaxies that are morphologically early type, but reside alongside spiral galaxies in color vs. stellar mass space. We test the idea that the majority of low-to-intermediate mass blue-sequence E/S0s may be settled products of past mergers evolving toward later-type morphology via disk regrowth. We find that blue-sequence E/S0s with stellar masses 1.0, comparable to those of spiral galaxies. Preliminary CO(1-0) maps reveal disk-like rotation of molecular gas in the inner regions of several of our blue-sequence E/S0s, which suggests that they may have gas disks suitable for stellar disk regrowth. At the current rate of star formation, many of our blue-sequence E/S0s will exhaust their atomic gas reservoirs in <~ 3 Gyr. Over the same time period, most of these galaxies are capable of substantial growth in the stellar component. Star formation in blue-sequence E/S0s appears to be bursty, and likely involves inflow trig...

  18. Bipolar Outflows and the Evolution of Stars

    OpenAIRE

    Frank, Adam

    1998-01-01

    Hypersonic bipolar outflows are a ubiquitous phenomena associated with both young and highly evolved stars. Observations of Planetary Nebulae, the nebulae surrounding Luminous Blue Variables such as $\\eta$ Carinae, Wolf Rayet bubbles, the circumstellar environment of SN 1987A and Young Stellar Objects all revealed high velocity outflows with a wide range of shapes. In this paper I review the current state of our theoretical understanding of these outflows. Beginning with Planetary Nebulae con...

  19. An Atlas of Spectrophotometric Landolt Standard Stars

    OpenAIRE

    Stritzinger, Maximilian; Suntzeff, Nicholas B.; Hamuy, Mario; Challis, Peter; Demarco, Ricardo; Germany, Lisa; Soderberg, A. M.

    2005-01-01

    We present CCD observations of 102 Landolt standard stars obtained with the R-C spectrograph on the CTIO 1.5 m telescope. Using stellar atmosphere models we have extended the flux points to our six spectrophotometric secondary standards, in both the blue and the red, allowing us to produce flux-calibrated spectra that span a wavelength range from 3050 \\AA to 1.1 \\micron. Mean differences between UBVRI spectrophotometry computed using Bessell's standard passbands and Landolt's published photom...

  20. 21 CFR 73.50 - Ultramarine blue.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ultramarine blue. 73.50 Section 73.50 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.50 Ultramarine blue. (a) Identity. The color additive ultramarine blue is a blue pigment obtained...

  1. Cold Dust in Three Massive Evolved Stars in the LMC

    CERN Document Server

    Boyer, M L; van Loon, J Th; Srinivasan, S; Clayton, G C; Kemper, F; Smith, L J; Matsuura, M; Woods, Paul M; Marengo, M; Meixner, M; Engelbracht, C; Gordon, K D; Hony, S; Indebetouw, R; Misselt, K; Okumura, K; Panuzzo, P; Riebel, D; Roman-Duval, J; Sauvage, M; Sloan, G C

    2010-01-01

    Massive evolved stars can produce large amounts of dust, and far-infrared (IR) data are essential for determining the contribution of cold dust to the total dust mass. Using Herschel, we search for cold dust in three very dusty massive evolved stars in the Large Magellanic Cloud: R71 is a Luminous Blue Variable, HD36402 is a Wolf-Rayet triple system, and IRAS05280-6910 is a red supergiant. We model the spectral energy distributions using radiative transfer codes and find that these three stars have mass-loss rates up to 10^-3 solar masses/year, suggesting that high-mass stars are important contributors to the life-cycle of dust. We found far-IR excesses in two objects, but these excesses appear to be associated with ISM and star-forming regions. Cold dust (T < 100 K) may thus not be an important contributor to the dust masses of evolved stars.

  2. Hypervelocity stars from young stellar clusters in the Galactic Centre

    CERN Document Server

    Fragione, Giacomo; Kroupa, Pavel

    2016-01-01

    The enormous velocities of the so called hypervelocity stars (HVSs) derive, likely, from close interactions with massive black holes, binary stars encounters or supernova explosions. In this paper, we investigate the origin of hypervelocity stars as consequence of the close interaction between the Milky Way central massive black hole and a passing-by young stellar cluster. We found that both single and binary HVSs may be generated in a burst-like event, as the cluster passes near the orbital pericentre. High velocity stars will move close to the initial cluster orbital plane and in the direction of the cluster orbital motion at the pericentre. The binary fraction of these HVS jets depends on the primordial binary fraction in the young cluster. The level of initial mass segregation determines the value of the average mass of the ejected stars. Some binary stars will merge, continuing their travel across and out of the Galaxy as blue stragglers.

  3. The half-century history of studies of Romano's star

    CERN Document Server

    Olga, Maryeva

    2014-01-01

    Luminous blue variables (LBVs) are rare objects of very high luminosity and mass loss rates, low wind velocities, exhibiting strong irregular photometric and spectral variability. They are generally believed to be a relatively short evolutionary stage in the life of a massive star, marking the transition from the Main Sequence toward Wolf-Rayet (WR) stars. However, recent studies indicate that progenitors of several supernovae underwent LBV-like eruptions. These studies support the view that at least some LBV stars are the end point of the evolution but not a transition phase. LBVs are rare objects, observations of whose in the Galaxy are inevitably connected with difficulties in determination of the distance and interstellar extinction. Hence, studying these rare objects in nearby galaxies is potentially more prospective. Therefore, investigation of the extragalactic star Romano's star (V532 or GR290) which is now classified as LBV/post-LBV star and shows late-WN spectrum, is very important for our understan...

  4. The Circumstellar Medium of Massive Stars in Motion

    CERN Document Server

    Mackey, Jonathan; Meyer, Dominique M -A; Gvaramadze, Vasilii V; Mohamed, Shazrene; Neilson, Hilding R; Mignone, Andrea

    2014-01-01

    The circumstellar medium around massive stars is strongly impacted by stellar winds, radiation, and explosions. We use numerical simulations of these interactions to constrain the current properties and evolutionary history of various stars by comparison with observed circumstellar structures. Two- and three-dimensional simulations of bow shocks around red supergiant stars have shown that Betelgeuse has probably only recently evolved from a blue supergiant to a red supergiant, and hence its bow shock is very young and has not yet reached a steady state. We have also for the first time investigated the magnetohydrodynamics of the photoionised H II region around the nearby runaway O star Zeta Oph. Finally, we have calculated a grid of models of bow shocks around main sequence and evolved massive stars that has general application to many observed bow shocks, and which forms the basis of future work to model the explosions of these stars into their pre-shaped circumstellar medium.

  5. Evaluation of dredged material proposed for ocean disposal from Red Hook/Bay Ridge project areas, New York

    Energy Technology Data Exchange (ETDEWEB)

    Pinza, M.R.; Barrows, E.S.; Borde, A.B. [Battelle/Marine Sciences Lab., Sequim, WA (United States)

    1996-09-01

    The objective of the Red HookIBay Ridge project was to evaluate proposed dredged material from these two areas to determine its suitability for unconfined ocean disposal at the Mud Dump Site. Sediment samples were collected from the Red Hook/Bay Ridge project areas. Tests and analyses were conducted. The evaluation of proposed dredged material from the Red Hook/Bay Ridge project areas consisted of bulk sediment chemical analyses, chemical analyses of dredging site water and elutriate, water-column and benthic acute toxicity tests. Twenty-four individual sediment core samples were collected from these two areas and analyzed for grain size, moisture content, and total organic carbon (TOC). Three composite sediment samples, representing Red Hook Channel and the two Bay Ridge Reaches to be dredged, were analyzed for bulk density, specific gravity, metals, chlorinated pesticides, polychlorinated biphenyl (PCB) congeners, polynuclear aromatic hydrocarbons (PAH), and 1,4-dichlorobenzene. Dredging site water and elutriate water, which is prepared from the suspended-particulate phase (SPP) of the three Red Hook Bay Ridge sediment composites, were analyzed for metals, pesticides, and PCBS. Benthic acute toxicity tests were performed. Water-column or SPP toxicity tests were performed. Bioaccumulation tests were also conducted.

  6. Meanest foundations and nobler superstructures: Hooke, Newton and the "compounding of the celestiall motions of the planets

    Science.gov (United States)

    Gal, Ofer

    This book is a historical-epistemological study of one the most consequential idea of early modern celestial mechanics: Robert Hooke's proposal to "compoun[d] the celestial motions of the planets of a direct motion by the tangent & an attractive motion towards a central body," a proposal which Isaac Newton adopted and realized in his Principia. Hooke's Programme was revolutionary both cosmologically and mathematically. It presented "the celestial motions," the proverbial symbol of stability and immutability, as a process of continuous change, and prescribed only parameters of rectilinear motions and rectilinear attractions for calculating their closed curved orbits. Yet the traces of Hooke's construction of his Programme for the heavens lead through his investigations in such earthly disciplines as microscopy, practical optics and horology, and the mathematical tools developed by Newton to accomplish it appear no less local and goal-oriented than Hooke's lenses and springs. This transgression of the boundaries between the theoretical, experimental and technological realms is reminiscent of Hooke's own free excursions in and out of the circles occupied by gentlemen-philosophers, university mathematicians, instrument makers, technicians and servants. It presents an opportunity to examine the social and epistemological distinctions, relations and hierarchies between those realms and their inhabitants, and compels a critical assessment of the philosophical categories they embody.

  7. "Hook"-calibration of GeneChip-microarrays: Chip characteristics and expression measures

    Directory of Open Access Journals (Sweden)

    Krohn Knut

    2008-08-01

    Full Text Available Abstract Background Microarray experiments rely on several critical steps that may introduce biases and uncertainty in downstream analyses. These steps include mRNA sample extraction, amplification and labelling, hybridization, and scanning causing chip-specific systematic variations on the raw intensity level. Also the chosen array-type and the up-to-dateness of the genomic information probed on the chip affect the quality of the expression measures. In the accompanying publication we presented theory and algorithm of the so-called hook method which aims at correcting expression data for systematic biases using a series of new chip characteristics. Results In this publication we summarize the essential chip characteristics provided by this method, analyze special benchmark experiments to estimate transcript related expression measures and illustrate the potency of the method to detect and to quantify the quality of a particular hybridization. It is shown that our single-chip approach provides expression measures responding linearly on changes of the transcript concentration over three orders of magnitude. In addition, the method calculates a detection call judging the relation between the signal and the detection limit of the particular measurement. The performance of the method in the context of different chip generations and probe set assignments is illustrated. The hook method characterizes the RNA-quality in terms of the 3'/5'-amplification bias and the sample-specific calling rate. We show that the proper judgement of these effects requires the disentanglement of non-specific and specific hybridization which, otherwise, can lead to misinterpretations of expression changes. The consequences of modifying probe/target interactions by either changing the labelling protocol or by substituting RNA by DNA targets are demonstrated. Conclusion The single-chip based hook-method provides accurate expression estimates and chip-summary characteristics

  8. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Frigaard, Peter; Brorsen, Michael

    Nærværende rapport beskriver foreløbige hovedkonklusioner på modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star i perioden 13/9 2004 til 12/11 2004.......Nærværende rapport beskriver foreløbige hovedkonklusioner på modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star i perioden 13/9 2004 til 12/11 2004....

  9. The nature of hypervelocity stars as inferred from their galactic trajectories

    CERN Document Server

    Svensson, Karl M; Davies, Melvyn B

    2007-01-01

    We have computed the galactic trajectories of twelve hypervelocity stars (HVSs) under the assumption that they originated in the Galactic Centre. We show that eight of these twelve stars are bound to the Galaxy. We consider the subsequent trajectories of the bound stars to compute their characteristic orbital period, which is 2 Gyr. All eight bound stars are moving away from the centre of the Galaxy, which implies that the stars' lifetimes are less than 2 Gyr. We thus infer that the observed HVSs are massive main sequence stars, rather than blue horizontal branch stars. The observations suggest that blue HVSs are ejected from the Galactic Centre roughly every 15 Myr. This is consistent with the observed population of blue stars in extremely tight orbits round the central super-massive black hole (SMBH), the so-called S-stars, if we assume that the HVSs are produced by the breakup of binaries. One of the stars in such a binary is ejected at high velocities to form a HVS; the other remains bound to the SMBH as ...

  10. Philosophy of experiment in early modern England: the case of Bacon, Boyle and Hooke.

    Science.gov (United States)

    Anstey, Peter R

    2014-01-01

    Serious philosophical reflection on the nature of experiment began in earnest in the seventeenth century. This paper expounds the most influential philosophy of experiment in seventeenth-century England, the Bacon-Boyle-Hooke view of experiment. It is argued that this can only be understood in the context of the new experimental philosophy practised according to the Baconian theory of natural history. The distinctive typology of experiments of this view is discussed, as well as its account of the relation between experiment and theory. This leads into an assessment of other recent discussions of early modern experiment, namely, those of David Gooding, Thomas Kuhn, J.E. Tiles and Peter Dear.

  11. Leakage of Oil Following Rupture of Pipeline P/15-4 to Hook of Holland

    OpenAIRE

    Kranenburg, C.

    1983-01-01

    This report presents computational results concerning the buoyancy-driven leakage of oil resulting from a possible rupture of the planned pipeline P/15-4 to Hook of Holland. The computations were commissioned by R.J. Brown and Associates (Netherlands) b.v. (RJBA Job No. 7004.02). The specifications of the pipeline and oil as made available by RJBA are listed in Table 1. Assumed properties of seawater are also listed. Leak volumes up to 400 m were calculated as functions of time after rupture ...

  12. The effects of different substrates on flowering of kohleria (Kohleria amabilis Hook.

    Directory of Open Access Journals (Sweden)

    Jerzy Hetman

    2012-12-01

    Full Text Available The aim of the study was to test the effects of different substrates on flowering of Kohleria amabilis Hook. belonging to Gesneriaceae family. Substrates used were: white peat, white peat + bark (1:1, white peat +perlite (1:1, white peat + sand (1:1, coir, low-bog peat, low-bog peat + bark (1:1. Substrates caused effects on flowering of a kohleria. The best of them occured low-bog peat + bark (1:1. Plants bloomed the earliest, for the longest time and plentyfully. Moreover they were hight and nicely leafy. The least useful was white peat.

  13. Delaware River water quality Bristol to Marcus Hook, Pennsylvania, August 1949 to December 1963

    Science.gov (United States)

    Keighton, Walter B.

    1965-01-01

    During the 14-year period from August 1949 to July 1963, the U.S. Geological Survey, in cooperation with the city of Philadelphia, collected samples of river water once each month in the 43-mile reach of the Delaware River from Bristol to Marcus Hook, Pa., and daily at Trenton, 10 miles upstream from Bristol. This part of the Delaware is an estuary into which salt water is brought by tides; fresh water flows into the estuary at Trenton, NJ, and farther downstream from the Schuylkill River and other tributaries of the Delaware. In March, April, and May, when fresh-water flow is high, the average concentration of dissolved solids in the water at Bristol was 76 ppm (parts per million), and at Marcus Hook 112 PPM In August and September, streamflow is lower, and the average concentration of dissolved solids increased to 117 PPM at Bristol and 804 PPM at Marcus Hook. Major salinity invasions of the Delaware River occurred in 1949, 1953, 1954, 1957, and 1963. In each of these years the fresh-water flow into the tidal river at Trenton was low during the period from July to October. The greatest dissolved-solids concentrations in these monthly samples were 160 PPM at Bristol and 4,000 PPM at Marcus Hook. At times the dissolved-oxygen concentration of the river water has become dangerously low, especially in that reach of the river between Wharton Street and League Island. At the Benjamin Franklin Bridge, one-third of the samples of river water were less than 30 percent saturated with oxygen; however, no trend, either for better or for worse, was apparent during the 14-year period. It is useful now to summarize these monthly analyses for the period 1949-63 even though a much more detailed description of water quality in this reach of the estuary will soon become available through the use of recording instrumental conditions. This compendium of water-quality data is useful as an explicit statement of water quality during the 14-year study period and is valuable for directing

  14. Flavonoids from the Stems of Croton caudatus Geisel. var. tomentosus Hook

    OpenAIRE

    Zhong-Mei Zou; Jun-Shan Yang; Yuan Wang; Hong-Wu Zhang; Zhi-Heng Su; Guo-An Zou

    2010-01-01

    A new flavone, named crotoncaudatin (1), was isolated from the stems of Croton caudatus Geisel. var. tomentosus Hook., together with nine known analogues: 3,5,6,7,8,3′,4′-heptamethoxyflavone (2), tangeretin (3), nobiletin (4), 5,6,7,4′-tetramethoxy-flavone (5), sinensetin (6), kaempferol (7), tiliroside (8), kaempferol-3-O-rutinoside (9) and rutin (10). The structures of the above compounds were established by a combination of spectroscopic methods, including HR-ESI-MS, 1H-NMR, 13C-NMR, HMQC ...

  15. Lateral malleolus hook plate for comminuted Weber A and B fractures: A retrospective study

    Directory of Open Access Journals (Sweden)

    Fang Zhenhua

    2013-01-01

    Full Text Available Background: The goal of managing the comminuted fracture of lateral malleolus is to restore length, rotation and alignment which might be more challenging with extensive comminution around the area of the distal tip. The common osteosynthesis techniques such as the one-third tubular plate, tension band wiring, K-wires, screws, or intramedullary nail may be insufficient in cases with a comminuted lateral malleolus. The anatomical hook plate is an alternative implant in such cases. We present our results of the comminuted lateral malleolar fractures (Weber A, B, managed by open reduction and internal fixation (ORIF with an anatomical hook plate of lateral malleolus (Königsee Implant Company, Germany. Materials and Methods: We retrospectively reviewed 20 patients of comminuted fracture of distal lateral malleolus between 2008 and 2010. There were 12 males and 8 females, right side was involved in 18 patients and left in 2. The mean age was 51.9 years (range 18-75 years. The fractures were categorized by Denis-Weber classification type A (n=1, B1 (n=1, B2 (n=13 and B3 (n=5. Nineteen cases were of closed injury and one of open injury (Gustilo Anderson type II. These patients underwent ORIF with a lateral malleolus anatomical hook plate. Followup including radiographs and clinical examinations were performed. The American Orthopedic Foot and Ankle Society (AOFAS ankle hindfoot scores were documented at followups. Results: The mean followup was 21.4 months (range 16-27 months. The average AOFAS score was 94.3 (range 78-100 points. A stable anatomic reduction and bony union were obtained in all the cases. The average time was 3.1 months (range 2.5-4 months. Four cases had complications like posttraumatic osteoarthritis, hardware impingement and superficial wound infection. Conclusion: A reasonably good stability can be obtained in distal most comminuted fractures of lateral malleolus with a lateral malleolus anatomical hook plate. We believe this

  16. Chemical constituents from Eucalyptus citriodora Hook leaves and their glucose transporter 4 translocation activities.

    Science.gov (United States)

    Wang, Chao; Yang, Jing; Zhao, Ping; Zhou, Qi; Mei, Zhinan; Yang, Guangzhong; Yang, Xinzhou; Feng, Yunjiang

    2014-07-15

    Bioassay-guided phytochemical investigation of the EtOAc fraction from the leaves of a Chinese medicinal herb, Eucalyptus citriodora Hook, resulted in the isolation of a new compound rhodomyrtosone E (1), along with 12 known compounds (2-13). The structure of the new compound was established by 1D and 2D NMR, MS data and X-ray crystallographic analysis. Betulinic acid (2) and corosolic acid (5) increased glucose transporter 4 (GLUT-4) translocation by 2.38 and 1.78-fold, respectively. PMID:24894556

  17. Aportación a la óptica de Robert Hooke

    OpenAIRE

    Urtubia Vicario, César

    1988-01-01

    La figura de Robert Hooke se nos ofrece como la personificación del espíritu de investigación y la fidelidad al método científico experimental del siglo XVII. Vinculado a los más sobresalientes hombres de ciencia ingleses de su época, contribuyó con aportaciones propias a la ciencias físicas, sobre todo a la mecánica y la óptica, la química y la biología Peer Reviewed

  18. Goniothalamin, a cytotoxic compound, isolated from Goniothalamus macrophyllus (Blume) Hook. f. & Thomson var. macrophyllus

    OpenAIRE

    Niwat Keawpradub; Arunporn Itharat; Chatchai Wattanapiromsakul; Puttachat Sangprapan; Boonsong Wangsintaweekul

    2005-01-01

    Bioassay guided fractionation by brine shrimp lethality test led to isolation of a cytotoxic compound, goniothalamin, from the root and stem of Goniothalamus macrophyllus (Blume) Hook. f. & Thomson var. macrophyllus. Goniothalamin showed a promising cytotoxicity (SRB assay) against colon cancer cell line (IC50 = 0.51±0.02 μg/ml), breast cancer cell lines (IC50= 0.95±0.02 μg/ml) and lung carcinoma (IC50 = 3.51± 0.03 μg/ml). LDH assay of goniothalamin suggested that it had no toxicity on cell m...

  19. Two New Phorbol-Type Diterpene Esters from Synadenium grantii Hook F. Leaves

    Directory of Open Access Journals (Sweden)

    Emad M. Hassan

    2012-03-01

    Full Text Available Two new phorbol-type diterpene esters has been isolated from the chloroform extract of the leaves of Synadenium grantii Hook F. and identified as 3,4,12,13-tetraacetylphorbol-20-phenylacetate and 4-deoxyphor bol-12,13-ditiglate for which the trivial names Synagrantol A & B respectively, were adopted. Furthermore, two known triterpenes were isolated. The structures of all isolated compounds were established by 1D and 2D NMR spectroscopy including 1H and 13C NMR, HSQC and HMBC techniques. The cytotoxicity as well as the antiparasitic activity of the chloroform extract was performed and proved to be active.

  20. "Clothed in triple blues": sorting out the Italian blues.

    Science.gov (United States)

    Bimler, David; Uusküla, Mari

    2014-04-01

    Cross-cultural comparisons of color perception and cognition often feature versions of the "similarity sorting" procedure. By interpreting the assignment of two color samples to different groups as an indication that the dissimilarity between them exceeds some threshold, sorting data can be regarded as low-resolution similarity judgments. Here we analyze sorting data from speakers of Italian, Russian, and English, applying multidimensional scaling to delineate the boundaries between perceptual categories while highlighting differences between the three populations. Stimuli were 55 color swatches, predominantly from the blue region. Results suggest that at least two Italian words for "blue" are basic, a similar situation to Russian, in contrast to English where a single "blue" term is basic.

  1. Extreme Star Formation

    OpenAIRE

    Turner, JL

    2010-01-01

    Extreme star formation includes star formation in starbursts and regions forming super star clusters. We survey the current problems in our understanding of the star formation process in starbursts and super star clusters - initial mass functions, cluster mass functions, star formation efficiencies, and radiative feedback into molecular clouds - that are critical to our understanding of the formation and survival of large star clusters, topics that will be the drivers of the observations of t...

  2. Planck stars

    CERN Document Server

    Rovelli, Carlo

    2014-01-01

    A star that collapses gravitationally can reach a further stage of its life, where quantum-gravitational pressure counteracts weight. The duration of this stage is very short in the star proper time, yielding a bounce, but extremely long seen from the outside, because of the huge gravitational time dilation. Since the onset of quantum-gravitational effects is governed by energy density --not by size-- the star can be much larger than planckian in this phase. The object emerging at the end of the Hawking evaporation of a black hole can can then be larger than planckian by a factor $(m/m_{\\scriptscriptstyle P})^n$, where $m$ is the mass fallen into the hole, $m_{\\scriptscriptstyle P}$ is the Planck mass, and $n$ is positive. The existence of these objects alleviates the black-hole information paradox. More interestingly, these objects could have astrophysical and cosmological interest: they produce a detectable signal, of quantum gravitational origin, around the $10^{-14} cm$ wavelength.

  3. Essential oil of Origanum majorana L., Illicium verum Hook. f. and Cinnamomum zeylanicum Blume: chemical and antimicrobial characterization Óleos essenciais de Origanum majorana L., Illicium verum Hook. f. e Cinnamomum zeylanicum Blume: caracterização química e antimicrobiana

    Directory of Open Access Journals (Sweden)

    J.M Freire

    2011-01-01

    Full Text Available Essential oils of Origanum majorana L. (marjoram, Illicium verum Hook. f. (star-anise and Cinnamomum zeylanicum Blume (cinnamon were obtained by steam distillation using a modified Clevenger device. The antimicrobial activity of each oil was evaluated against the bacteria Staphylococcus aureus, Escherichia coli and the fungi Aspergillus flavus and Aspergillus parasiticus by observing their growth and/or mycelial inhibition through comparison with the standard dish (without oil. The essential oils were analyzed using a gas chromatograph coupled to a mass spectrometer for identification and coupled to a flame ionization detector for quantification. The major constituents of marjoram, star-anise and cinnamon essential oils were 4-terpineol, trans-anetole and cinnamic aldehyde, respectively. In in vitro tests, essential oils of marjoram and cinnamon promoted an inhibitory effect on the bacteria S. aureus and E. coli, while the essential oil of star-anise presented activity only against E. coli. Marjoram, star-anise and cinnamon oils were effective against the studied fungi, presenting an inhibitory effect. The minimal inhibitory concentration for the mycelial growth of A. parasiticus was 1 and 0.01 µL mL-1 for star-anise and cinnamon oils, respectively. The minimal inhibitory concentration for A. parasiticus was 0.25, 2 and 2 µL mL-1 for cinnamon, star-anise and marjoram oils, respectively.Óleos essenciais de Origanum majorana L. (manjerona, Illicium verum Hook. f. (anis estrelado e Cinnamomum zeylanicum Blume (canela foram obtidos pela técnica de arraste a vapor d'água com aparelho de Clevenger modificado. Foram avaliadas as atividades antimicrobianas de cada um sobre as bactérias Staphylococcus aureus, Escherichia coli e para os fungos Aspergillus flavus e Aspergillus parasiticus, observando o crescimento e/ou inibição micelial, comparando-se estes com a placa-padrão (sem óleo. Os óleos essenciais foram analisados em cromat

  4. The Fate of Luminous Compact Blue Galaxies: An Environmental Approach

    CERN Document Server

    Crawford, S M; Glenn, A; Hössel, J G

    2004-01-01

    Luminous Compact Blue Galaxies (LCBGs) are a heterogeneous class which dominate an intermediate phase of galaxy evolution. These sources account for the majority of the star formation between 0.3star formation rates (SFR) and metallicities from low dispersion Mulit-Object Spectroscopy (MOS); (2) dynamical masses from line-widths measured via high dispersion MOS; and (3) cluster velocity dispersions of LCBGs relative to other cluster em...

  5. Nickel allergy in patch-tested female hairdressers and assessment of nickel release from hairdressers' scissors and crochet hooks

    DEFF Research Database (Denmark)

    Thyssen, Jacob Pontoppidan; Milting, Kristina; Bregnhøj, Anne;

    2009-01-01

    BACKGROUND: Hand eczema as well as nickel contact allergy is prevalent among hairdressers. Recently, two female hairdressers were diagnosed with nickel contact allergy-related hand eczema following prolonged skin contact with scissors and crochet hooks used during work. OBJECTIVES: To determine...... the proportion of hairdressers' scissors and crochet hooks that released an excessive amount of nickel and to determine the prevalence of nickel allergy among patch-tested female hairdressers. MATERIALS: Random hairdressers' stores in Copenhagen were visited. The dimethylglyoxime (DMG) test was used to assess...... of scissors and 7 (53.8%; 95% CI = 26.0 - 82.0) of 13 crochet hooks released an excessive amount of nickel. The prevalence of nickel allergy was higher among middle-aged and older female hairdressers than among young female hairdressers. CONCLUSIONS: The prevalence of nickel allergy was lower among young...

  6. [Surgical technique of displacement and retraction of the heart with a pigtail shaped hook and Tentacles Heart Positioner].

    Science.gov (United States)

    Shimamura, Yoshiei; Mochizuki, Y; Yamada, Y; Eda, K; Shibasaki, I; Inoue, Y; Miyoshi, S

    2007-07-01

    We describe a novel heart retracting system with Tentacles Heart Positioner (Sumitomo Bakelite, Tokyo) during off-pump coronary artery bypass grafting (OPCAB). The heart retracting system is composed of a pigtail shaped hook attached to a flexible Universal Stabilizer Arm (Estech, Minneapolis). After Tentacles suction device is applied on the surface of the heart, the retracting system is fixed on the sternal retracter so that the hook can hang and support the retracting tubes of the sucker. By regulating the shape of the Universal Stabilizer Arm and the position of the hook, the retracting system can lift the heart sufficiently and maintain the optimal position of the heart during OPCAB procedure. Together with Tentacles Heart Positioner, the heart retracting system provides excellent exposure of target coronary arteries with minimal effect on hemodynamics.

  7. Transfissural Route Used for Preoperative Localization of Small Pulmonary Lesions with a Short Hook Wire and Suture System

    Energy Technology Data Exchange (ETDEWEB)

    Iguchi, Toshihiro, E-mail: iguchi@ba2.so-net.ne.jp; Hiraki, Takao, E-mail: takaoh@tc4.so-net.ne.jp; Gobara, Hideo, E-mail: gobara@cc.okayama-u.ac.jp; Fujiwara, Hiroyasu, E-mail: hirofujiwar@gmail.com; Matsui, Yusuke, E-mail: wckyh140@yahoo.co.jp [Okayama University Medical School, Department of Radiology (Japan); Sugimoto, Seiichiro, E-mail: sei1675sugi@yahoo.co.jp; Toyooka, Shinichi, E-mail: shintoyooka@gmail.com; Oto, Takahiro, E-mail: yellowpeachoto@hotmail.com; Miyoshi, Shinichiro, E-mail: smiyoshi@md.okayama-u.ac.jp [Okayama University Medical School, Department of General Thoracic Surgery (Japan); Kanazawa, Susumu, E-mail: susumu@cc.okayama-u.ac.jp [Okayama University Medical School, Department of Radiology (Japan)

    2015-02-15

    PurposeWe retrospectively evaluated the results of the transfissural route for preoperative localization with a short hook wire and suture system for video-assisted thoracoscopic surgery (VATS).MethodsEleven patients with 11 tumors underwent CT-guided transfissural placement of a hook wire before VATS. This route was selected for all patients, because the distance between the tumor and interlobar fissure was much shorter than the required distance traversed using the conventional approach. Complications were evaluated using the National Cancer Institute Common Terminology Criteria for Adverse Events Version 4.0.ResultsThe hook wire was successfully placed using the transfissural route in all but one case. Of these ten successful placements, two tumors needed a second puncture for optimal placement, because the CT scan showed that the first hook wire was not properly placed in the lung. In one patient, we did not attempt replacement after the first placement was incorrect. In ten successful procedures, the mean distance traversed in the parenchyma of the unaffected lung lobe was 27.9 mm. The distance between the pleura and placed hook wire was significantly shorter than the estimated distance between the pleura and hook wire using the conventional route (mean 16.3 vs. 40.9 mm; P = 0.0002). Grade 1 adverse events occurred (11 pneumothoraxes and 4 pulmonary hemorrhages). No grade 2 or higher adverse event was observed.ConclusionsThe transfissural route used for preoperative localization before VATS is useful for selected patients because this route may allow for more limited lung parenchyma resection.

  8. Temporal hooking variability among sharks on south-eastern Australian demersal longlines and implications for their management

    Directory of Open Access Journals (Sweden)

    Matt K. Broadhurst

    2014-12-01

    Full Text Available An experiment was done to quantify species-specific variation in temporal hooking rates from demersal longlines targeting various carcharhinids off south eastern Australia, with a view to reducing the incidental catches of protected species, including the scalloped hammerhead Sphyrna lewini, great hammerhead Sphyrna mokarran and grey nurse Carcharias taurus. The longline comprised a 9600 m mainline, separated into four sections (termed lines each with 120 gangions (20 m apart rigged with hook timers and 16/0 circle hooks baited with either sea mullet Mugil cephalus or eastern Australian salmon Arripis trutta. The mainline was deployed on each of 17 nights (between 19:30 and 23:30 h, with two lines retrieved after 7 and 14 h respectively. From a total of 8160 hooks, 246 timers were activated without hooking fish. Twenty-two species comprising 684 individuals were caught, including 52 S. lewini, 12 C. taurus, 11 S. mokarran and 1 loggerhead turtle Caretta caretta. Several environmental factors, including water temperature, moon phase and depth had mostly homogeneous, positive effects on catches. The only identified variables that might be used to considerably reduce the catches of Sphyrna were soak time and/or diurnal gear retrieval, with most individuals hooked during daylight. Simply mandating shorter deployments and within nocturnal retrieval might limit exploitation, especially among juveniles (<150cm total length. For the studied fishery to approach sustainability, future research is required to investigate other gear modifications for improving size and species selectivity, and/or operational procedures for mitigating discard and escape mortalities.

  9. Why Do Proteins Glow Blue?

    CERN Document Server

    Sarkar, Sohini; Hazra, Partha; Mandal, Pankaj

    2014-01-01

    Recent literatures reported blue-green emission from amyloid fibril as exclusive signature of fibril formation. This unusual visible luminescence is regularly used to monitor fibril growth. Blue-green emission has also been observed in crystalline protein and in solution. However, the origin of this emission is not known exactly. Our spectroscopic study of serum proteins reveals that the blue-green emission is a property of protein monomer. Evidences suggest that semiconductor-like band structure of proteins with the optical band-gap in the visible region is possibly the origin of this phenomenon. We show here that the band structure of proteins is primarily the result of electron delocalization through the peptide chain, rather than through the hydrogen bond network in secondary structure.

  10. Hook removal from a loggerhead sea turtle (Caretta caretta: Report of a tricky surgery under difficult conditions

    Directory of Open Access Journals (Sweden)

    João Pedro Barreiros

    2015-08-01

    Full Text Available A sub adult Caretta caretta was found on the 23rd August, 2014 ca. 16 nautical miles south off S. Miguel Island, Azores (Northeast Atlantic, with a large pelagic trawl hook inside its mouth. The individual was kept in a basin of sea water and sent by boat to Terceira Island following instructions by the Azores Regional Government via the Environmental Authority in order to be examined by the author and, if possible, undergo the necessary hook removal procedures. In this note, we describe the surgical procedures and how the turtle was evaluated both pre- and post-surgery.

  11. Hook removal from a loggerhead sea turtle (Caretta caretta):Report of a tricky surgery under difficult conditions

    Institute of Scientific and Technical Information of China (English)

    João Pedro Barreiros

    2015-01-01

    A sub adult Caretta caretta was found on the 23rd August, 2014 ca. 16 nautical miles south off S. Miguel Island, Azores (Northeast Atlantic), with a large pelagic trawl hook inside its mouth. The individual was kept in a basin of sea water and sent by boat to Terceira Island following instructions by the Azores Regional Government via the Environmental Authority in order to be examined by the author and, if possible, undergo the necessary hook removal procedures. In this note, we describe the surgical procedures and how the turtle was evaluated both pre- and post-surgery.

  12. Measure of the stars

    Energy Technology Data Exchange (ETDEWEB)

    Henbest, N.

    1984-12-13

    The paper concerns the Hertzsprung-Russel (H-R) diagram, which is graph relating the brightness to the surface temperature of the stars. The diagram provides a deep insight into the fundamental properties of the stars. Evolution of the stars; the death of a star; distances; and dating star clusters, are all briefly discussed with reference to the H-R diagram.

  13. The blue-collar brain.

    Science.gov (United States)

    Van Orden, Guy; Hollis, Geoff; Wallot, Sebastian

    2012-01-01

    Much effort has gone into elucidating control of the body by the brain, less so the role of the body in controlling the brain. This essay develops the idea that the brain does a great deal of work in the service of behavior that is controlled by the body, a blue-collar role compared to the white-collar control exercised by the body. The argument that supports a blue-collar role for the brain is also consistent with recent discoveries clarifying the white-collar role of synergies across the body's tensegrity structure, and the evidence of critical phenomena in brain and behavior. PMID:22719730

  14. A survey of small RNA population during FR-induced apical hook opening

    Directory of Open Access Journals (Sweden)

    Ying eLi

    2014-04-01

    Full Text Available Photomorphogenesis is a mechanism employed by plants to regulate their architecture and developmental program in response to light conditions. As they emerge into light for the first time, dark-grown seedlings employ a rapid and finely-controlled photomorphogenic signaling network. Small RNAs have increasingly been revealed to play an important role in regulating multiple aspects of plant development, by modulating the stability of mRNAs. The rapid alteration of the mRNA transcriptome is a known hallmark of the de-etiolation response, thus we investigated the small RNA transcriptome during this process in specific seedling tissues. Here we describe a survey of the small RNA expression profile in four tissues of etiolated soybean seedlings, the cotyledons, hypocotyl and the convex and concave sides of the apical hook. We also investigate how this profile responds to a one-hour far-red light treatment. Our data suggests that miRNAs show a different global profile between these tissues and treatments, suggesting a possible role for tissue- and treatment-specific expression in the differential morphology of the seedling on de-etiolation. Further evidence for the role of miRNA in light-regulated development is given by the de-etiolation responses of a hypomorphic ago1 mutant, which displays reduced and delayed photomorphogenic responses in apical hook and cotyledon angle to far-red light.

  15. A Segunda Lei da Termodinamica na formulacao da Lei de Hooke

    CERN Document Server

    De Abreu, R

    2002-01-01

    Hooke's Law is analyzed taking the Second Law of Thermodynamics into consideration. It is shown that the energy of a spring isn't always 1/2 k xx - this value is actually the energy of the spring plus the energy of the atmosphere that surrounds it. On a quasi-isentropic aproximation in which the dynamic force is approximately the same as the static force, k is not a constant. Only by considering an ideal spring where k is constant and only on a static regime, can we say the energy is 1/2 k xx. For any dynamic regime of such an ideal spring, the energy of the spring is a function of its temperature and therefore is different from 1/2 k xx. If any given mass is moving attached to an ideal spring, the movement will eventually cease even if such movement occurs in vacuum. The dynamic force is not the static force kx. The Second Law of Thermodynamics is essential in order to formulate Hooke's Law.

  16. US-guided preoperative hook-wire localization of nonpalpable breast lesions

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Tae Beom; Lee, Sang Kwon; Kim, Hye Jung; Ryeom, Hun Kyu; Kim, Tae Hun; Kim, Yong Ju; Kang, Duk Sik; Lee, Young Ha; Park, Ho Yong [Kyungpook National University College of Medicine, Taegu (Korea, Republic of)

    2000-12-15

    To evaluate the feasibility and efficacy of US-guided preoperative wire localization of nonpalpable breast lesions. US-guided preoperative wire localization was performed upon 45 nonpalpable breast lesions including 14 nonpalpable masses, 11 nonpalpable masses with microcalcifications, 11 ductal lesions, 9 with microcalcifications. No local anesthesia was performed during the localization procedure. Under the US-guidance, the needle with the hook-wire was inserted into the lesion until the hook of the wire reached 1 cm beyond the posterior margin of the lesion. Precise wire positioning was confirmed by mammography. Specimen radiography or specimen ultrasonography was performed in all cases. US-guided preoperative wire localization was successfully achieved in all cases. The time required for US-guided wire localization was less than five minutes. All lesions were successfully removed by surgical excision. Successful removal was confirmed by specimen radiography or specimen ultrasonography, gross findings of the specimen and consistency between radiographic and pathologic findings. The histologic diagnosis of 45 lesions were 7 ductal carcinoma in situ, 8 invasive ductal carcinoma, 6 fibroadenoma, 8 intraductal papilloma, 2 atypical ductal hyperplasia, and 14 fibrocystic changes. No complications were occurred during and after the procedure. US-guided preoperative wire localization for excisional biopsy is simple, safe, and accurate method in the histologic diagnosis of nonpalpable breast lesions detectable with ultrasonography.

  17. Speculative pragmatism and intimate arrangements: online hook-up devices in gay life.

    Science.gov (United States)

    Race, Kane

    2015-01-01

    This paper considers how certain functions of online hook-up devices are participating in the emergence of new forms of sexual relation, new distributions of intimacy and new sexual arrangements. Though not without precedent, it argues that online hook-up devices generally act in gay culture as 'framing devices', framing sex as a 'no-strings' encounter via their default application. These frames are variously rejected, reconfigured, re-embedded or confounded by participants; they become subject to various forms of overflowing. Understanding this dynamic, its typical forms of connection and estrangement, is pivotal for grasping the emergence of new forms of sexual community and new sexual publics among gay men--and/or 'un-community', as some have put it. My analysis prompts a series of methodological reflections wrought from the encounter it stages between queer theory and Science and Technology Studies. At a time when marriage and monogamy are increasingly monopolising the public discourse of gay life, digital devices are affording novel ways of arranging sex, intimacy and sexual community, with their own qualities and limitations. PMID:24992161

  18. Studies on mosquito larvicidal properties of Eucalyptus citriodora Hook (family-Myrtaceae).

    Science.gov (United States)

    Singh, R K; Dhiman, R C; Mittal, P K

    2007-12-01

    Hexane extract obtained from leaves of Eucalyptus citriodora Hook was tested against larvae of Anopheles stephensi Liston, Culex quinquefasciatus Say and Aedes aegypti Linn to assess its toxicity and growth inhibiting activity. The results showed better activity of hexane extract against larvae of An. stephensi Liston as compared to the larvae of Cx. quinquefasciatus Say and Ae. aegypti Linn. The LC50 values against IVth instar larvae of three species were 69.86, 81.12 & 91.76 ppm respectively after 24 hours and 26.7, 29.9 & 38.8 ppm respectively after 72 hours. At lowest concentration viz. 10 ppm, 73% larvae of An. stephensi Liston failed to emergence as adult mosquito while in Cx. quinquefasciatus Say and Ae. aegypti Linn only 10 & 6% larvae failed to emerge. Further observations showed some morphological abnormalities in same pupae which could not moult normally. These results clearly indicated growth inhibition effect of the hexane extract of Eucalyptus against mosquito larvae, particularly Anopheles species. Thus Eucalyptus citriodora Hook, which is commonly found in Northern India, has a great potential for the development of an eco-friendly herbal insecticidal product for control of mosquito breeding. PMID:18697593

  19. Drosophila Hook-Related Protein (Girdin) Is Essential for Sensory Dendrite Formation.

    Science.gov (United States)

    Ha, Andrew; Polyanovsky, Andrey; Avidor-Reiss, Tomer

    2015-08-01

    The dendrite of the sensory neuron is surrounded by support cells and is composed of two specialized compartments: the inner segment and the sensory cilium. How the sensory dendrite is formed and maintained is not well understood. Hook-related proteins (HkRP) like Girdin, DAPLE, and Gipie are actin-binding proteins, implicated in actin organization and in cell motility. Here, we show that the Drosophila melanogaster single member of the Hook-related protein family, Girdin, is essential for sensory dendrite formation and function. Mutations in girdin were identified during a screen for fly mutants with no mechanosensory function. Physiological, morphological, and ultrastructural studies of girdin mutant flies indicate that the mechanosensory neurons innervating external sensory organs (bristles) initially form a ciliated dendrite that degenerates shortly after, followed by the clustering of their cell bodies. Importantly, we observed that Girdin is expressed transiently during dendrite morphogenesis in three previously unidentified actin-based structures surrounding the inner segment tip and the sensory cilium. These actin structures are largely missing in girdin mutant. Defects in cilia are observed in other sensory organs such as those mediating olfaction and taste, suggesting that Girdin has a general role in forming sensory dendrites in Drosophila. These suggest that Girdin functions temporarily within the sensory organ and that this function is essential for the formation of the sensory dendrites via actin structures.

  20. The blue supergiant MN18 and its bipolar circumstellar nebula

    CERN Document Server

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

    2015-01-01

    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 \\approx 21 kK. The star is highly reddened, E(B-V)\\approx 2 mag. Adopting an absolute visual magnitude of M_V=-6.8\\pm0.5 (typical of B1 supergiants), MN18 has a luminosity of log L/Lsun \\approx 5.42\\pm0.30, a mass-loss rate of \\approx (2.8-4.5)\\times10^{-7} Msun/yr, and resides at a distance of \\approx 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 (She...

  1. Hook Benefit Evaluation on the Increase of Urban Construction Land and the Decrease of Rural Construction Land in the Suburbs of Chongqing City,China

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    According to the socio-economic statistical data and the land use data of Jingguan Town in the year 2008,hook benefit evaluation index system suitable for the actual situation of research region is determined,based on the systematic analyses of the basic data of current status and the related information of hook in research region.Fuzzy Comprehensive Evaluation Method is adopted to evaluate the increase of construction land of Jingguan Town before and after the hook.Result shows that the economic,social and ecological benefits of research region have significantly improved after the hook.And the fuzzy comprehensive evaluation index system and evaluation methods established in this research can provide references for the hook benefit evaluation in the suburbs of Chongqing City,China.

  2. Star Formation Rates in Low Surface Brightness Galaxies

    NARCIS (Netherlands)

    Pickering, T. E.; Impey, C. D.; van Gorkom, J.; Bothun, G. D.

    1994-01-01

    The low surface brightness (LSB) disk galaxies found in recent surveys (e.g.,\\ Schombert et al. 1992, AJ, 103, 1107) tend to be blue and gas rich. These properties along with their low mean surface luminosity and H i densities imply an inefficient mode of star formation. The Hα images that we presen

  3. Modeling blue stragglers in young clusters

    Institute of Scientific and Technical Information of China (English)

    Pin Lu; Li-Cai Deng; Xiao-Bin Zhang

    2011-01-01

    A grid of binary evolution models are calculated for the study of a blue straggler (BS) population in intermediate age (log Age =7.85 - 8.95) star clusters.The BS formation via mass transfer and merging is studied systematically using our models.Both Case A and B close binary evolutionary tracks are calculated for a large range of parameters.The results show that BSs formed via Case B are generally bluer and even more luminous than those produced by Case A.Furthermore,the larger range in orbital separations of Case B models provides a probability of producing more BSs than in Case A.Based on the grid of models,several Monte-Carlo simulations of BS populations in the clusters in the age range are carried out.The results show that BSs formed via different channels populate different areas in the color magnitude diagram (CMD).The locations of BSs in CMD for a number of clusters are compared to our simulations as well.In order to investigate the influence of mass transfer efficiency in the models and simulations,a set of models is also calculated by implementing a constant mass transfer efficiency,β =0.5,during Roche lobe overflow (Case A binary evolution excluded).The result shows BSs can be formed via mass transfer at any given age in both cases.However,the distributions of the BS populations on CMD are different.

  4. Chemical Evolution of Blue Compact Galaxies

    Institute of Scientific and Technical Information of China (English)

    Fei Shi; Xu Kong; Fu-Zhen Cheng

    2006-01-01

    Based on a sample of 72 Blue Compact Galaxies (BCGs) observed with the 2.16 m telescope of the National Astronomical Observatories, Chinese Academy of Sciences (NAOC) and about 4000 strong emission line galaxies from the Sloan Digital Sky Survey,we analyzed their chemical evolution history using the revised chemical evolution model of Larsen et al. Our sample covers a much larger metallicity range (7.2<12+log(O/H) <9.0). We found that, in order to reproduce the observed abundance pattern and gas fraction over the whole metallicity range, a relatively continuous star formation history is needed for high metallicity galaxies, while assuming a series of instantaneous bursts with long quiescent periods (some Gyrs) for low metallicity galaxies. Model calculations also show that only the closed-box model is capable of reproducing the observational data over the whole metallicity range. Models that consider the ordinary winds and/or inflow can only fit the observations in the low metallicity range, and a model with enriched wind cannot fit the data in the whole metallicity range. This implies that the current adopted simple wind and inflow models are not applicable to massive galaxies, where the underlying physics of galactic winds or inflow could be more complicated.

  5. The Star Formation History of LGS 3

    CERN Document Server

    Miller, B W; Lee, M G; Kim, S C; Hodge, P

    2001-01-01

    We have determined the distance and star formation history of the Local Group dwarf galaxy LGS 3 from deep Hubble Space Telescope WFPC2 observations. LGS 3 is intriguing because ground-based observations showed that, while its stellar population is dominated by old, metal-poor stars, there is a handful of young, blue stars. Also, the presence of HI gas makes this a possible ``transition object'' between dwarf spheroidal and dwarf irregular galaxies. The HST data are deep enough to detect the horizontal branch and young main sequence for the first time. A new distance of D=620+/-20 kpc has been measured from the positions of the TRGB, the red clump, and the horizontal branch. The mean metallicity of the stars older than 8 Gyr is Fe/H = -1.5 +/- 0.3. The most recent generation of stars has Fe/H ~ -1. For the first few Gyr the global star formation rate was several times higher than the historical average and has been fairly constant since then. However, we do see significant changes in stellar populations and s...

  6. SPITZER SAGE-SMC INFRARED PHOTOMETRY OF MASSIVE STARS IN THE SMALL MAGELLANIC CLOUD

    International Nuclear Information System (INIS)

    We present a catalog of 5324 massive stars in the Small Magellanic Cloud (SMC), with accurate spectral types compiled from the literature, and a photometric catalog for a subset of 3654 of these stars, with the goal of exploring their infrared properties. The photometric catalog consists of stars with infrared counterparts in the Spitzer SAGE-SMC survey database, for which we present uniform photometry from 0.3to24 μm in the UBVIJHKs +IRAC+MIPS24 bands. We compare the color-magnitude diagrams and color-color diagrams to those of stars in the Large Magellanic Cloud (LMC), finding that the brightest infrared sources in the SMC are also the red supergiants, supergiant B[e] (sgB[e]) stars, luminous blue variables, and Wolf-Rayet stars, with the latter exhibiting less infrared excess, the red supergiants being less dusty and the sgB[e] stars being on average less luminous. Among the objects detected at 24 μm in the SMC are a few very luminous hypergiants, four B-type stars with peculiar, flat spectral energy distributions, and all three known luminous blue variables. We detect a distinct Be star sequence, displaced to the red, and suggest a novel method of confirming Be star candidates photometrically. We find a higher fraction of Oe and Be stars among O and early-B stars in our SMC catalog, respectively, when compared to the LMC catalog, and that the SMC Be stars occur at higher luminosities. We estimate mass-loss rates for the red supergiants, confirming the correlation with luminosity even at the metallicity of the SMC. Finally, we confirm the new class of stars displaying composite A and F type spectra, the sgB[e] nature of 2dFS1804 and find the F0 supergiant 2dFS3528 to be a candidate luminous blue variable with cold dust.

  7. Tight LMC massive star clusters R 127 and R 128

    CERN Document Server

    Heydari-Malayeri, M; Walborn, N R; Walborn, Nolan R.

    2003-01-01

    We study the Large Magellanic Cloud (LMC) star clusters R 127 and R 128 using imaging and spectroscopy obtained at the ESO NTT telescope. An advanced image restoration technique allows us to resolve these two clusters into at least 14 and 33 stars respectively and obtain their photometry. In particular, we show that the core of R 127 is composed of at least four stars and identify the Luminous Blue Variable (LBV) component. The closest neighbor of the LBV (star #8) is 1".5 away. Moreover, from medium dispersion spectroscopy we determine the spectral types for 19 stars in and near both clusters, and in particular present the first spatially resolved observation of the second brightest component of the R 127 cluster (star #3) situated 3".3 from the LBV. By comparing with evolutionary models we also look into the stellar ages. The oldest stars of the cluster are ~ 6-8 Myr old, whereas the most massive star of the region (#7), formed ~ 3 Myr ago as an 80 solar mass star, has turned into an LBV, the ``R 127'' star...

  8. The Blue Revolution in Asia

    DEFF Research Database (Denmark)

    Ponte, Stefano; Kelling, Ingrid; Jespersen, Karen Sau;

    2014-01-01

    In this article, we examine the upgrading trajectories of selected aquaculture value chains in four Asian countries and the links between upgrading and three factors of value chain governance: coordination mechanisms; types of drivers; and domestic regulation. We find instances of improving produ...... of upgrading the "blue revolution" in Asia...

  9. Liquid biofuels from blue biomass

    DEFF Research Database (Denmark)

    Kádár, Zsófia; Jensen, Annette Eva; Bangsø Nielsen, Henrik;

    2011-01-01

    Marine (blue) biomasses, such as macroalgaes, represent a huge unexploited amount of biomass. With their various chemical compositions, macroalgaes can be a potential substrate for food, feed, biomaterials, pharmaceuticals, health care products and also for bioenergy. Algae use seawater as a growth...

  10. Nobel Prize for blue LEDs

    Science.gov (United States)

    Kraftmakher, Yaakov

    2015-05-01

    A brief review of lighting technologies is presented. Unavoidable restrictions for incandescent light bulbs caused by the Planck distribution and properties of the human eye are illustrated. The efficiency and luminous efficacy of thermal radiation are calculated for various temperatures; the results clearly show the limitations for thermal radiators. The only way to overcome these limitations is using non-thermal radiators, such as fluorescent lamps and light-emitting diodes (LEDs). Unique advantages of LEDs undoubtedly made a revolution in this field. A crucial element of this progress is the blue LEDs (Nobel Prize 2014). Some experiments with a blue and a green LED are described: (i) the luminescence triggered in a green-yellow phosphor inside a white LED by the blue LED; (ii) radiant spectra and ‘efficiency droop’ in the LEDs; (iii) modulation of the blue LED up to 4 MHz; and (iv) the h/e ratio from the turn-on voltage of the green LED. The experiments are suitable for undergraduate laboratories and usable as classroom demonstrations.

  11. Blue Ocean vs. Five Forces

    NARCIS (Netherlands)

    A.E. Burke (Andrew); A.J. van Stel (André); A.R. Thurik (Roy)

    2010-01-01

    textabstractThe article reports on the authors' research in the Netherlands which focused on a profit model in Dutch retail stores and a so-called blue-ocean approach which requires a new market that attracts consumers and increases profits. Topics include the competitive strategy approach to increa

  12. Discovery of an opportunistic starfish pathogen, Orchitophrya stellarum, in captive blue crabs, Callinectes sapidus.

    Science.gov (United States)

    Small, H J; Miller, T L; Coffey, A H; Delaney, K L; Schott, E; Shields, J D

    2013-10-01

    Histophagous scuticociliate infections were discovered in blue crabs, Callinectes sapidus, held in research facilities at the Virginia Institute of Marine Science. Ciliates were observed infecting every tissue examined including the gills, heart, muscle, hepatopancreas, and epidermis. Hemolymph smears and histological tissue sections indicated a morphological similarity to Mesanophrys chesapeakensis, the only recorded histophagous ciliate infecting blue crabs. However, subsequent analysis of the ribosomal ITS region (ITS1-5.8S-ITS2) of the ciliate indicated the parasite was Orchitophrya stellarum, a parasitic ciliate previously reported infecting sea stars from Europe, Australia, and North America. A simple Polymerase Chain Reaction (PCR-RFLP) assay was developed to detect and differentiate between O. stellarum and M. chesapeakensis. Its application confirmed the presence of O. stellarum infecting blue crabs held in an additional research facility in Maryland. For growth studies, cultures of O. stellarum grew optimally on 10% blue crab serum in crustacean saline held at 10-20°C. A field survey of blue crabs collected during the winters of 2011-2012 and sea stars (Asterias forbesi) during the winter of 2010 from the Chesapeake Bay and eastern shore of Virginia did not identify additional infected individuals.

  13. Supernovae from yellow, blue supergiants: origin and consequences for stellar evolution

    Science.gov (United States)

    Meynet, Georges; Georgy, Cyril; Saio, Hideyuki; Kudritzki, Rolf-Peter; Groh, Jose

    2015-08-01

    A few core collapse supernovae progenitors have been found to be yellow or blue supergiants. We shall discuss possible scenarios involving single and close binary evolution allowing to explain this kind of core collapse supernova progenitors. According to stellar models for both single and close binaries, blue supergiants, at the end of their nuclear lifetimes and thus progenitors of core collapse supernovae, present very different characteristics for what concerns their surface compositions, rotational surface velocities and pulsational properties with respect to blue supergiants in their core helium burning phase. We discuss how the small observed scatter of the flux-weighted gravity-luminosity (FWGL) relation of blue supergiants constrains the evolution of massive stars after the Main-Sequence phase and the nature of the progenitors of supernovae in the mass range between 12 and 40 solar masses. The present day observed surface abundances of blue supergiants, of their pulsational properties, as well as the small scatter of the FWGL relation provide strong constraints on both internal mixing and mass loss in massive stars and therefore on the end point of their evolution.

  14. Blue lobes in the Hydra A cluster central galaxy

    Science.gov (United States)

    Mcnamara, Brian R.

    1995-01-01

    We present new U- and I-band images of the centrally dominant galaxy in the Hydra A cluster, obtained with the 2.5 m Isaac Newton Telescope at La Palma. The galaxy is centered in a poor, X-ray-luminous cluster whose gaseous intracluster medium is apparently cooling at a rate of m-dot(sub CF) approximately 3000 solar masses/yr. The galaxy's structure is that of a normal giant elliptical galaxy, apart from the central approximately 8 x 6 arcsec (approximately 12 x 9 kpc) region which contains an unusually blue, lobelike structure that is spatially coincident with a luminous emission-line nebula in rotation about the nucleus. Based on near spatial coincidence of the central continuum structure and the emission-line nebula, we suggest that the blue continuum is due to a warm stellar population in a central disk. In order to isolate and study the structure of the disk, we have subtracted a smooth galactic background model from the U-band image. The disk's surface brightness profiles along its major and minor axes decline roughly exponentially with radius. The disk's axial ratio is consistent with a nearly edge-on thick disk or a thin disk that is inclined with respect to the line of sight. The bluest regions, located a few arcsec on either side of the nucleus (giving the lobelike appearance), may be due to locally enhanced star formation or a seeing-blurred ring of young stars embedded in the disk observed nearly edge-on. If star-formation is occurring with the local initial mass function, the central color, surface brightness, and dynamical mass would be consistent with models for star formation at a rate of less than and approximately 1 solar masses/yr which has persisted for the past approximately 10(exp 9) yr, a short burst (10(exp 7) yr) of star formation at a rate of approximately 30 solar masses/yr which occurred less than and approximately 10(exp 8) yr ago, or an instantaneous burst of star formation which occurred approximately 5 x 10(exp 7) yr ago. While the

  15. The Neutral ISM in Nearby Luminous Compact Blue Galaxies

    CERN Document Server

    Garland, C A; Williams, J P; Guzmán, R; Castander, F J

    2003-01-01

    We observed 20 nearby Luminous Compact Blue Galaxies (LCBGs) in HI and CO(J=2-1) with the GBT and JCMT. These ~L^star galaxies are blue, high surface brightness, starbursting, high metallicity galaxies with an underlying older stellar population. They are common at z~1, but rare in the local Universe. It has been proposed that intermediate redshift LCBGs may be the progenitors of local dwarf ellipticals or low luminosity spirals, or that they may be more massive disks forming from the center outward to become L^star galaxies. To discriminate among various possible evolutionary scenarios, we have measured the dynamical masses and gas depletion time scales of this sample of nearby LCBGs. We find that local LCBGs span a wide range of dynamical masses, from 4 x 10^9 to 1 x 10^11 M_solar (measured within R_25). Molecular gas in local LCBGs is depleted quite quickly, in 30 to 200 million years. The molecular plus atomic gas is depleted in 30 million to 10 billion years; however, ~80% of the local LCBGs deplete thei...

  16. Peculiar early-type galaxies with central star formation

    Institute of Scientific and Technical Information of China (English)

    Chong Ge; Qiu-Sheng Gu

    2012-01-01

    Early-type galaxies (ETGs) are very important for understanding the formation and evolution of galaxies.Recent observations suggest that ETGs are not simply old stellar spheroids as we previously thought.Widespread recent star formation,cool gas and dust have been detected in a substantial fraction of ETGs.We make use of the radial profiles of g - r color and the concentration index from the Sloan Digital Sky Survey database to pick out 31 peculiar ETGs with central blue cores.By analyzing the photometric and spectroscopic data,we suggest that the blue cores are caused by star formation activities rather than the central weak active galactic nucleus.From the results of stellar population synthesis,we find that the stellar population of the blue cores is relatively young,spreading from several Myr to less than one Gyr.In 14 galaxies with H I observations,we find that the average gas fraction of these galaxies is about 0.55.The bluer galaxies show a higher gas fraction,and the total star formation rate (SFR) correlates very well with the H l gas mass.The star formation history of these ETGs is affected by the environment,e.g.in the denser environment the H 1 gas is less and the total SFR is lower.We also discuss the origin of the central star formation of these early-type galaxies.

  17. An Unwelcome Place for New Stars (artist concept)

    Science.gov (United States)

    2006-01-01

    [figure removed for brevity, see original site] Poster Version Suppression of Star Formation from Supermassive Black Holes This artist's concept depicts a supermassive black hole at the center of a galaxy. NASA's Galaxy Evolution Explorer found evidence that black holes -- once they grow to a critical size -- stifle the formation of new stars in elliptical galaxies. Black holes are thought to do this by heating up and blasting away the gas that fuels star formation. The blue color here represents radiation pouring out from material very close to the black hole. The grayish structure surrounding the black hole, called a torus, is made up of gas and dust. Beyond the torus, only the old red-colored stars that make up the galaxy can be seen. There are no new stars in the galaxy.

  18. Variable stars in the open cluster NGC 2141

    CERN Document Server

    Luo, Yanping

    2014-01-01

    We report the results of a search for variable stars in the open cluster NGC 2141. Ten variable stars are detected, among which nine are new variable stars and they are classified as three short period W UMa type eclipsing binaries, two EA type eclipsing binaries, one EB type eclipsing binary, one very short period RS CVn type eclipsing binary, one d type RR Lyrae variable star, and one unknown type variable star. The membership and physical properties are discussed, based on their light curves, positions in the CMDs, spatial locations and periods. A known EB type eclipsing binary is also identified as a blue struggler candidate of the cluster. Furthermore, we find that all eclipsing contact binaries have prominently asymmetric eclipses and O Connell effect (O Connell 1951) which increases with the decrease of the orbital periods. This suggests that the O Connell effect is probably related to the evolution of the orbital period in short period eclipsing binary systems.

  19. EAARL Coastal Topography--Sandy Hook Unit, Gateway National Recreation Area, New Jersey, Post-Nor'Ida, 2009

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A digital elevation model (DEM) of a portion of the Sandy Hook Unit of the Gateway National Recreation Area in New Jersey, post-Nor'Ida (November 2009 nor'easter)...

  20. 33 CFR 334.102 - Sandy Hook Bay, Naval Weapons Station EARLE, Piers and Terminal Channel, restricted area...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Sandy Hook Bay, Naval Weapons Station EARLE, Piers and Terminal Channel, restricted area, Middletown, New Jersey. 334.102 Section 334.102 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS...

  1. The Evolution of Luminous Compact Blue Galaxies: Disks or Spheroids?

    CERN Document Server

    Pisano, D J; Garland, C A; Guzman, R; Castander, F J; Perez-Gallego, J

    2011-01-01

    Luminous compact blue galaxies (LCBGs) are a diverse class of galaxies characterized by high luminosity, blue color, and high surface brightness that sit at the critical juncture of galaxies evolving from the blue to the red sequence. As part of our multi-wavelength survey of local LCBGs, we have been studying the HI content of these galaxies using both single-dish telescopes and interferometers. Our goals are to determine if single-dish HI observations represent a true measure of the dynamical mass of LCBGs and to look for signatures of recent interactions that may be triggering star formation in LCBGs. Our data show that while some LCBGs are undergoing interactions, many appear isolated. While all LCBGs contain HI and show signatures of rotation, the population does not lie on the Tully-Fisher relation nor can it evolve onto it. Furthermore, the HI maps of many LCBGs show signatures of dynamically hot components, suggesting that we are seeing the formation of a thick disk or spheroid in at least some LCBGs....

  2. "Hook"-calibration of GeneChip-microarrays: Theory and algorithm

    Directory of Open Access Journals (Sweden)

    Preibisch Stephan

    2008-08-01

    Full Text Available Abstract Background: The improvement of microarray calibration methods is an essential prerequisite for quantitative expression analysis. This issue requires the formulation of an appropriate model describing the basic relationship between the probe intensity and the specific transcript concentration in a complex environment of competing interactions, the estimation of the magnitude these effects and their correction using the intensity information of a given chip and, finally the development of practicable algorithms which judge the quality of a particular hybridization and estimate the expression degree from the intensity values. Results: We present the so-called hook-calibration method which co-processes the log-difference (delta and -sum (sigma of the perfect match (PM and mismatch (MM probe-intensities. The MM probes are utilized as an internal reference which is subjected to the same hybridization law as the PM, however with modified characteristics. After sequence-specific affinity correction the method fits the Langmuir-adsorption model to the smoothed delta-versus-sigma plot. The geometrical dimensions of this so-called hook-curve characterize the particular hybridization in terms of simple geometric parameters which provide information about the mean non-specific background intensity, the saturation value, the mean PM/MM-sensitivity gain and the fraction of absent probes. This graphical summary spans a metrics system for expression estimates in natural units such as the mean binding constants and the occupancy of the probe spots. The method is single-chip based, i.e. it separately uses the intensities for each selected chip. Conclusion: The hook-method corrects the raw intensities for the non-specific background hybridization in a sequence-specific manner, for the potential saturation of the probe-spots with bound transcripts and for the sequence-specific binding of specific transcripts. The obtained chip characteristics in combination

  3. Possible Local Spiral Counterparts to Compact Blue Galaxies at Intermediate Redshift

    CERN Document Server

    Barton, E J; Barton, Elizabeth J.; Zee, Liese van

    2001-01-01

    We identify nearby disk galaxies with optical structural parameters similar to those of intermediate-redshift compact blue galaxies. By comparing HI and optical emission-line widths, we show that the optical widths substantially underestimate the true kinematic widths of the local galaxies. By analogy, optical emission-line widths may underrepresent the masses of intermediate-z compact objects. For the nearby galaxies, the compact blue morphology is the result of tidally-triggered central star formation: we argue that interactions and minor mergers may cause apparently compact morphology at higher redshift.

  4. Flavour production of Stilton blue cheese microflora

    OpenAIRE

    Gkatzionis, Konstantinos

    2010-01-01

    In the blue cheese Stilton the starter mould Penicillium roqueforti grows and sporulates during the ripening period and is considered to be responsible for the unique blue cheese aroma. However, the sporulation of the mould, which results in the formation of blue veins, takes place in a fraction of the Stilton matrix which overall is very heterogeneous. Most blue cheeses develop a secondary microflora of yeasts which may affect their aroma. The aim of this study was to investigate the yeast f...

  5. Bio-synthesis of silver nanoparticles using Potentilla fulgens Wall. ex Hook. and its therapeutic evaluation as anticancer and antimicrobial agent

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, Amit Kumar [Department of Pharmaceutical Technology Biotechnology, National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, 160062 Punjab (India); Tripathy, Debabrata [Department of Biotechnology and Bioinformatics, North Eastern Hill University, Shillong, 793002 Meghalaya (India); Choudhary, Alka [Department of Natural Products, National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, 160062 Punjab (India); Aili, Pavan Kumar [Department of Pharmaceutical Technology Biotechnology, National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, 160062 Punjab (India); Chatterjee, Anupam [Department of Biotechnology and Bioinformatics, North Eastern Hill University, Shillong, 793002 Meghalaya (India); Singh, Inder Pal [Department of Natural Products, National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, 160062 Punjab (India); Banerjee, Uttam Chand, E-mail: ucbanerjee@niper.ac.in [Department of Pharmaceutical Technology Biotechnology, National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, 160062 Punjab (India)

    2015-08-01

    The present study aims to develop an easy and eco-friendly method for the synthesis of silver nanoparticles using extracts from the medicinal plant, Potentilla fulgens and evaluation of its anticancer and antimicrobial properties. The various parts of P. fulgens were screened and the root extract was found to have the highest potential for the synthesis of nanoparticles. The root extracts were able to quickly reduce Ag{sup +} to Ag{sup 0} and stabilized the nanoparticles. The synthesis of nanoparticles was confirmed by UV–Visible spectrophotometry and further characterized using Zeta sizer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). Electron microscopic study showed that the size of the nanoparticle was in the range of 10 to 15 nm and spherical in shape. The studies of phytochemical analysis of nanoparticles indicated that the adsorbed components on the surface of nanoparticles were mainly flavonoid in nature. Furthermore, nanoparticles were evaluated as cytotoxic against various cancer cell lines and 0.2 to 12 μg/mL nanoparticles showed good toxicity. The IC{sub 50} value of nanoparticles was found to be 4.91 and 8.23 μg/mL against MCF-7 and U-87 cell lines, respectively. Additionally, the apoptotic effect of synthesized nanoparticles on normal and cancer cells was studied using trypan blue assay and flow-cytometric analysis. The results indicate the synthesized nanoparticle ability to kill cancer cells compared to normal cells. The nanoparticles also exhibited comparable antimicrobial activity against both Gram-positive and Gram-negative bacteria. - Highlights: • Bio-synthesis of AgNPs using a medicinal plant Potentilla fulgens Wall. ex Hook. • Optimization of NP synthesis and its characterization using various techniques • Determination of therapeutic potential in terms of anticancer and antimicrobial properties • To know the mechanistic

  6. Bio-synthesis of silver nanoparticles using Potentilla fulgens Wall. ex Hook. and its therapeutic evaluation as anticancer and antimicrobial agent

    International Nuclear Information System (INIS)

    The present study aims to develop an easy and eco-friendly method for the synthesis of silver nanoparticles using extracts from the medicinal plant, Potentilla fulgens and evaluation of its anticancer and antimicrobial properties. The various parts of P. fulgens were screened and the root extract was found to have the highest potential for the synthesis of nanoparticles. The root extracts were able to quickly reduce Ag+ to Ag0 and stabilized the nanoparticles. The synthesis of nanoparticles was confirmed by UV–Visible spectrophotometry and further characterized using Zeta sizer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). Electron microscopic study showed that the size of the nanoparticle was in the range of 10 to 15 nm and spherical in shape. The studies of phytochemical analysis of nanoparticles indicated that the adsorbed components on the surface of nanoparticles were mainly flavonoid in nature. Furthermore, nanoparticles were evaluated as cytotoxic against various cancer cell lines and 0.2 to 12 μg/mL nanoparticles showed good toxicity. The IC50 value of nanoparticles was found to be 4.91 and 8.23 μg/mL against MCF-7 and U-87 cell lines, respectively. Additionally, the apoptotic effect of synthesized nanoparticles on normal and cancer cells was studied using trypan blue assay and flow-cytometric analysis. The results indicate the synthesized nanoparticle ability to kill cancer cells compared to normal cells. The nanoparticles also exhibited comparable antimicrobial activity against both Gram-positive and Gram-negative bacteria. - Highlights: • Bio-synthesis of AgNPs using a medicinal plant Potentilla fulgens Wall. ex Hook. • Optimization of NP synthesis and its characterization using various techniques • Determination of therapeutic potential in terms of anticancer and antimicrobial properties • To know the mechanistic apoptosis effect of AgNPs

  7. Biomechanical Analysis of the Proximal Adjacent Segment after Multilevel Instrumentation of the Thoracic Spine: Do Hooks Ease the Transition?

    Science.gov (United States)

    Metzger, Melodie F; Robinson, Samuel T; Svet, Mark T; Liu, John C; Acosta, Frank L

    2016-06-01

    Study Design Biomechanical cadaveric study. Objective Clinical studies indicate that using less-rigid fixation techniques in place of the standard all-pedicle screw construct when correcting for scoliosis may reduce the incidence of proximal junctional kyphosis and improve patient outcomes. The purpose of this study is to investigate whether there is a biomechanical advantage to using supralaminar hooks in place of pedicle screws at the upper-instrumented vertebrae in a multilevel thoracic construct. Methods T7-T12 spines were biomechanically tested: (1) intact; (2) following a two-level pedicles screw fusion from T9 to T11; and after proximal extension of the fusion to T8-T9 with (3) bilateral supra-laminar hooks, (4) a unilateral hook + unilateral screw hybrid, or (5) bilateral pedicle screws. Specimens were nondestructively loaded while three-dimensional kinematics and intradiscal pressure at the supra-adjacent level were recorded. Results Supra-adjacent hypermobility was reduced when bilateral hooks were used in place of pedicle screws at the upper-instrumented level, with statistically significant differences in lateral bending and torsion (p < 0.05 and p < 0.001, respectively). Disk pressures in the supra-adjacent segment were not statistically different among top-off techniques. Conclusions The use of supralaminar hooks at the top of a multilevel posterior fusion construct reduces the stress at the proximal uninstrumented motion segment. Although further data is needed to provide a definitive link to the clinical occurrence of PJK, this in vitro study demonstrates the potential benefit of "easing" the transition between the stiff instrumented spine and the flexible native spine and is the first to demonstrate these results with laminar hooks. PMID:27190735

  8. Chemical and anti-ulcer evaluation of Jodina rhombifolia (Hook. & Arn. Reissek extracts

    Directory of Open Access Journals (Sweden)

    Jarbas A. Montanha

    2009-03-01

    Full Text Available Jodina rhombifolia (Hook. & Arn. Reissek (Santalaceae is a medicinal plant popularly used as an anti-ulcer medicine. The plant native from Southern Brazil was chemically investigated and tested for its in vivo gastric anti-ulcer property by chloride acid/ethanol model. The chromatographic analysis of the hydroethanol extract of its leaves revealed the presence of C-glycosylflavonoids. From the n-butanol fraction of the hydroethanol extract of its aerial parts, vicenin-2 was isolated as the main component and identified by spectroscopic methods; and, a direct comparison with authentic samples was made. This fraction afforded three other C-glycosylflavonoids: vitexin, orientin and swertisin; all of them identified by direct comparison with authentic samples. We found that the oral administration of aqueous and hydroethanolic extracts led to a significant decrease in the ulcer index.

  9. Concentric ring flywheel with hooked ring carbon fiber separator/torque coupler

    Science.gov (United States)

    Kuklo, Thomas C.

    1999-01-01

    A concentric ring flywheel with expandable separators, which function as torque couplers, between the rings to take up the gap formed between adjacent rings due to differential expansion between different radius rings during rotation of the flywheel. The expandable separators or torque couplers include a hook-like section at an upper end which is positioned over an inner ring and a shelf-like or flange section at a lower end onto which the next adjacent outer ring is positioned. As the concentric rings are rotated the gap formed by the differential expansion there between is partially taken up by the expandable separators or torque couplers to maintain torque and centering attachment of the concentric rings.

  10. Incising the thick retrolental fibrovascular tissue with a hooked sclerotome in persistent hyperplastic primary vitreous.

    Science.gov (United States)

    Shiraki, K; Moriwaki, M; Kohno, T; Yanagihara, N; Miki, T

    1999-01-01

    A technique for incising thick retrolental fibrovascular tissue and extensive cyclitic membrane is reported in a case of anterior persistent hyperplastic primary vitreous. A membranectomy was performed in a 1-month-old post-lensectomy baby via a limbal approach. A sclerotome tip was hooked to cut through an extremely thick fibrovascular tissue by rotating the sclerotome by its grip. Sutherland microscissors (Grieshaber, Switzerland) and a vitrectomy cutter were used for further membranectomy. The baby was followed-up until age 18 months. A total of 3 membranectomy sessions were required because of rapid cyclitic membrane formation, severe centripetal retraction of the membrane on the ciliary processes, and posterior synechia. Thorough membranectomy and cutting the iris edge maintained a clear pupillary area during the 13-month postoperative period. Extremely thick retrolental fibrovascular tissue is a challenging condition that can be dealt with by delicate instrumentation. PMID:10574499

  11. Flavonoids from the Stems of Croton caudatus Geisel. var. tomentosus Hook

    Directory of Open Access Journals (Sweden)

    Zhong-Mei Zou

    2010-02-01

    Full Text Available A new flavone, named crotoncaudatin (1, was isolated from the stems of Croton caudatus Geisel. var. tomentosus Hook., together with nine known analogues: 3,5,6,7,8,3′,4′-heptamethoxyflavone (2, tangeretin (3, nobiletin (4, 5,6,7,4′-tetramethoxy-flavone (5, sinensetin (6, kaempferol (7, tiliroside (8, kaempferol-3-O-rutinoside (9 and rutin (10. The structures of the above compounds were established by a combination of spectroscopic methods, including HR-ESI-MS, 1H-NMR, 13C-NMR, HMQC and HMBC spectra. All compounds were isolated from and identified in this species for the first time and compounds 1-6 are new for the genus Croton.

  12. Flavonoids from the stems of Croton caudatus Geisel. var. tomentosus Hook.

    Science.gov (United States)

    Zou, Guo-An; Su, Zhi-Heng; Zhang, Hong-Wu; Wang, Yuan; Yang, Jun-Shan; Zou, Zhong-Mei

    2010-02-26

    A new flavone, named crotoncaudatin (1), was isolated from the stems of Croton caudatus Geisel. var. tomentosus Hook., together with nine known analogues: 3,5,6,7,8,3',4'-heptamethoxyflavone (2), tangeretin (3), nobiletin (4), 5,6,7,4'-tetramethoxy-flavone (5), sinensetin (6), kaempferol (7), tiliroside (8), kaempferol-3-O-rutinoside (9) and rutin (10). The structures of the above compounds were established by a combination of spectroscopic methods, including HR-ESI-MS, 1H-NMR, 13C-NMR, HMQC and HMBC spectra. All compounds were isolated from and identified in this species for the first time and compounds 1-6 are new for the genus Croton.

  13. A viral suppressor protein inhibits host RNA silencing by hooking up with Argonautes

    KAUST Repository

    Jin, Hailing

    2010-05-01

    RNA viruses are particularly vulnerable to RNAi-based defenses in the host, and thus have evolved specific proteins, known as viral suppressors of RNA silencing (VSRs), as a counterdefense. In this issue of Genes & Development, Azevedo and colleagues (pp. 904-915) discovered that P38, the VSR of Turnip crinkle virus, uses its glycine/tryptophane (GW) motifs as an ARGONAUTE (AGO) hook to attract and disarm the host\\'s essential effector of RNA silencing. Several GW motif-containing cellular proteins are known to be important partners of AGOs in RNA silencing effector complexes in yeast, plants, and animals. The GW motif appears to be a versatile and effective tool for regulating the activities of RNA silencing pathways, and the use of GW mimicry to compete for and inhibit host AGOs may be a strategy used by many pathogens to counteract host RNAi-based defenses. © 2010 by Cold Spring Harbor Laboratory Press.

  14. A BIOMECHANICAL ANALYSIS OF UNILATERAL HOOKED-SULCATED EXTERNAL FIXATOR ON OSTEOMINED TIBIA

    Institute of Scientific and Technical Information of China (English)

    段德宇; 刘国平; 杜靖远; 饶振玉

    1998-01-01

    Four tibiae removed from 30~40 years males, who died of accidents in less than 12 hour, were osteomized at medium part. Then these tibiae were fixed by an unilateral hooked-sulcated external fixator (UHSEF), and the hone-fixator system was used as a model of external fixatitm of tibial fracture. The axial compression, distraction, torsion, antero-posterior and lateral bending rigidly and the strain of the pins were determined in this system, Based on the results, we found that compared with the configuration of four paralled pins,the rigidity of the fan-like configuratoa didn't decrease significantly if the angle between lateral and medium pins was less than 45°. But the reverse was true when the frame separation increased from 5 to 8 can. What'more, the pin strain decreased if the rigidity of the system was improved. These data provided a theoretical basis of biomechanies for the improvement of UHSEF.

  15. Determination of organochlorine pesticides in water using dynamic hook-type liquid-phase microextraction

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pai-Shan; Huang, Shih-Pin [Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Fuh, Ming-Ren, E-mail: msfuh@mail.scu.edu.tw [Department of Chemistry, Soochow University, Taipei, Taiwan (China); Huang, Shang-Da, E-mail: sdhuang@mx.nthu.edu.tw [Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2009-08-11

    We developed a simple and efficient headspace liquid-phase microextraction (LPME) technique named dynamic hook-type liquid-phase microextraction (DHT-LPME) and used it in combination with gas chromatography-mass spectrometry (GC-MS) and an electron capture detector (ECD). Aqueous specimens of organochlorine pesticides (OCPs) were used as model compounds to demonstrate the effectiveness of the technique. In the present study, the calibration curves were linear over at least 2 orders of magnitude with R{sup 2} values of 0.997. The method detection limits (MDLs) varied from 2 to 44.0 ng L{sup -1}. The precision of DHT-LPME ranged from 6.5 to 14.4%. The relative recoveries of OCPs in rainwater were more than 84.2%. Enrichment factors (EF) in the range 275-1127 were obtained using DHT-LPME.

  16. Goniothalamin, a cytotoxic compound, isolated from Goniothalamus macrophyllus (Blume Hook. f. & Thomson var. macrophyllus

    Directory of Open Access Journals (Sweden)

    Niwat Keawpradub

    2005-08-01

    Full Text Available Bioassay guided fractionation by brine shrimp lethality test led to isolation of a cytotoxic compound, goniothalamin, from the root and stem of Goniothalamus macrophyllus (Blume Hook. f. & Thomson var. macrophyllus. Goniothalamin showed a promising cytotoxicity (SRB assay against colon cancer cell line (IC50 = 0.51±0.02 μg/ml, breast cancer cell lines (IC50= 0.95±0.02 μg/ml and lung carcinoma (IC50 = 3.51± 0.03 μg/ml. LDH assay of goniothalamin suggested that it had no toxicity on cell membrane. Cytotoxic evaluation of goniothalamin to normal cell revealed moderate toxicity against skin fibroblast (IC50 = 26.73± 1.92 μg/ml and human fibroblast (IC50 = 11.99±0.15 μg/ml.

  17. Numerical Analysis Of Hooke Jeeves-Runge Kutta To Determine Reaction Rate Equation In Pyrrole Polymerization

    International Nuclear Information System (INIS)

    The numerical analysis of Hooke Jeeves Methods combined with Runge Kutta Methods is used to determine the exact model of reaction rate equation of pyrrole polymerization. Chemical polymerization of pyrrole was conducted with FeCI3 / pyrrole solution at concentration ratio of 1.62 mole / mole and 2.18 mole / mole with varrying temperature of 28, 40, 50, and 60 oC. FeCl3 acts as an oxidation agent to form pyrrole cation that will polymerize. The numerical analysis was done to examine the exact model of reaction rate equation which is derived from reaction equation of initiation, propagation, and termination. From its numerical analysis, it is found that the pyrrole polymerization follows third order of pyrrole cation concentration

  18. Triggered Star Formation by Massive Stars

    OpenAIRE

    Lee, Hsu-Tai; Chen, W. P.

    2005-01-01

    We present our diagnosis of the role that massive stars play in the formation of low- and intermediate-mass stars in OB associations (the Lambda Ori region, Ori OB1, and Lac OB1 associations). We find that the classical T Tauri stars and Herbig Ae/Be stars tend to line up between luminous O stars and bright-rimmed or comet-shaped clouds; the closer to a cloud the progressively younger they are. Our positional and chronological study lends support to the validity of the radiation-driven implos...

  19. Scaling of precipitation extremes with temperature in the French Mediterranean region: What explains the hook shape?

    Science.gov (United States)

    Drobinski, P.; Alonzo, B.; Bastin, S.; Silva, N. Da; Muller, C.

    2016-04-01

    Expected changes to future extreme precipitation remain a key uncertainty associated with anthropogenic climate change. Extreme precipitation has been proposed to scale with the precipitable water content in the atmosphere. Assuming constant relative humidity, this implies an increase of precipitation extremes at a rate of about 7% °C-1 globally as indicated by the Clausius-Clapeyron relationship. Increases faster and slower than Clausius-Clapeyron have also been reported. In this work, we examine the scaling between precipitation extremes and temperature in the present climate using simulations and measurements from surface weather stations collected in the frame of the HyMeX and MED-CORDEX programs in Southern France. Of particular interest are departures from the Clausius-Clapeyron thermodynamic expectation, their spatial and temporal distribution, and their origin. Looking at the scaling of precipitation extreme with temperature, two regimes emerge which form a hook shape: one at low temperatures (cooler than around 15°C) with rates of increase close to the Clausius-Clapeyron rate and one at high temperatures (warmer than about 15°C) with sub-Clausius-Clapeyron rates and most often negative rates. On average, the region of focus does not seem to exhibit super Clausius-Clapeyron behavior except at some stations, in contrast to earlier studies. Many factors can contribute to departure from Clausius-Clapeyron scaling: time and spatial averaging, choice of scaling temperature (surface versus condensation level), and precipitation efficiency and vertical velocity in updrafts that are not necessarily constant with temperature. But most importantly, the dynamical contribution of orography to precipitation in the fall over this area during the so-called "Cevenoles" events, explains the hook shape of the scaling of precipitation extremes.

  20. Food habits of blue grouse

    Science.gov (United States)

    Stewart, R.E.

    1944-01-01

    The food habits of Blue Grouse vary from a simple winter diet that is made up predominantly of coniferous needles to a complex diet during the summer months, characterized by great variety of foods including green leaves, fruits and seeds, flowers, animal matter and coniferous needles. The spring and fall, which represent the transition periods between these two, are characterized by feeding habits that are generally intermediate. The diets of the two species of Blue Grouse, Dendrugapus obscurus and Dendragapus juliginosus, are quite similar as far as major types of food are concerned, but they differ considerably in the species that are taken. Such differences reflect differences in the vegetation within the ecologic and geographic ranges occupied by the two species.