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Sample records for hii region gum31

  1. Star forming regions towards Gum 31: distribution of the molecular gas

    NASA Astrophysics Data System (ADS)

    Vazzano, M. M.; Cappa, C. E.; Vasquez, J.; Rubio, M.

    2015-08-01

    We analyze the distribution of the molecular gas associated with IRAS and 2MASS sources, young stellar objects linked to the Hii region Gum31. We based our studies on observations obtained with the APEX telescope, located in the north of Chile. We used observations of different CO isotopologues, CS(7-6) and HCO(4-3) lines. The sources are located on the edge of the Gum31 Hii region, whose shock front substantially affects the morphology of their molecular environs. The observations revealed that in the surroundings of the sources there is molecular gas associated with the nebula, which is shown by the CO(3-2) emission, with small high density clumps detected in CO(3-2).

  2. The environs of the H II region Gum 31

    NASA Astrophysics Data System (ADS)

    Cappa, C.; Niemela, V. S.; Amorín, R.; Vasquez, J.

    2008-01-01

    Aims:We analyze the distribution of the interstellar matter in the environs of the H ii region Gum 31, excited by the open cluster NGC 3324, located in the complex Carina region, with the aim of investigating the action of the massive stars on the surrounding neutral material. Methods: We use neutral hydrogen 21-cm line data, radio continuum images at 0.843, 2.4 and 4.9 GHz, 12CO(1-0) observations, and IRAS and MSX infrared data. Results: Adopting a distance of 3 kpc for the H ii region and the ionizing cluster, we derived an electron density of 33±3 cm-3 and an ionized mass of (3.3±1.1)×103 M⊙ based on the radio continuum data at 4.9 GHz. The H i 21-cm line images revealed an H i shell surrounding the H ii region. The H i structure is 10.0 ± 1.7 pc in radius, has a neutral mass of 1500 ± 500 M⊙, and is expanding at 11 km s-1. The associated molecular gas amounts to (1.1 ± 0.5)×105 M⊙, being its volume density of about 350 cm-3. This molecular shell could represent the remains of the cloud where the young open cluster NGC 3324 was born or could have originated by the shock front associated with the H ii region. The difference between the ambient density and the electron density of the H ii region suggests that the H ii region is expanding. The distributions of the ionized and molecular material, along with that of the emission in the MSX band A, suggest that a photodissociation region has developed at the interface between the ionized and molecular gas. The copious UV photon flux from the early type stars in NGC 3324 keeps the H ii region ionized. The characteristics of a relatively large number of the IRAS, MSX, and 2MASS point sources projected onto the molecular envelope are compatible with protostellar candidates, showing the presence of active star forming regions. Very probably, the expansion of the H ii region has triggered stellar formation in the molecular shell.

  3. HRM: HII Region Models

    NASA Astrophysics Data System (ADS)

    Wenger, Trey V.; Kepley, Amanda K.; Balser, Dana S.

    2017-07-01

    HII Region Models fits HII region models to observed radio recombination line and radio continuum data. The algorithm includes the calculations of departure coefficients to correct for non-LTE effects. HII Region Models has been used to model star formation in the nucleus of IC 342.

  4. Turbulence in HII regions

    NASA Astrophysics Data System (ADS)

    O'dell, C. R.

    1986-10-01

    It has been known for many decades that the Reynolds number in HII regions must be very high and that the corresponding fine scale flow must be turbulent. Even though the theoretical relation between turbulent element separation and random velocity was derived by Kolmogoroff over forty years ago, there have been only a few attempts to test this theory and its corresponding assumptions. An attempt by Munch for M42 with marginal velocity resolution lead to ambiguous results, although more recent studies by Jean Rene Roy and his colleagues have been more credible. The internal velocities of a number of HII regions were systematically studied and the theory was tested with considerable certainty. The results should be important for the determination of the energy balance of HII regions and the relation of small scale motion to the process of star formation.

  5. General properties of HII regions in galaxies

    NASA Technical Reports Server (NTRS)

    Smirnov, M. A.; Komberg, B. V.

    1979-01-01

    The structure, electron density, and dimensions of HII regions in galaxies are discussed. These parameters are correlated to the chemical composition gradient along the galactic radius, the dimensions of the three largest HII regions in the galaxy, and the amount of hydrogen in the galaxy, as well as the mass, dimensions, and total optical luminosity of the galaxy. The relationships of HII regions to star formation and galactic nucleus activity are discussed and the kinematic properties of the SB and Sab galaxies are related to the size of HII regions.

  6. Turbulence in HII regions: New results

    NASA Astrophysics Data System (ADS)

    Joncas, Gilles

    HII regions were the first interstellar objects where scale dependant brightness and velocity fluctuations were indentified (von Hoerner 1951, Courtes 1955, Munch 1958). The study of turbulent motions in HII regions was then forgotten for many years until the work of Joncas and O'Dell which started in 1985. I will present my deductions stemming from the analysis of the velocity fields of 6 HII regions (Sh 142, M17, Sh 158, Sh 170 and Sh 212). New data from the radial velocity AND density fields of the HII region Sh 269 will also be shown. The analysis was done using the well known two-point correlation functions. However I innovated by using the higher order structure functions. PDF calculations were also done hinting at the presence of intermittency in Sh 269.

  7. From Ultracompact to Extended HII Regions

    NASA Astrophysics Data System (ADS)

    Franco, J.; Garcia-Segura, G.

    1996-05-01

    The dynamical evolution of HII regions and wind-driven bubbles in dense clouds is studied. In particular, we address two different issues: 1) the conditions in which ultracompact HII (UCHII) regions can reach pressure equilibrium with their surrounding medium (and thereby stall their expansion), and 2) the appearance of a powerful dynamic instability in expanding HII regions. At pressure equilibrium the ionized regions become static and, as long as the ionization sources and the ambient gas densities remain about constant, the resulting UCHII regions are stable and long lived. The equilibrium sizes and densities, R_{S,eq} ~ 3 x 10(-2) F48(1/3) T_{HII,4}(2/3) P_7(-2/3) pc and n_{i,eq} ~ 4 x 10(4) P_7 T(-1) _{HII,4} cm(-3) (where F48 is the photoionizing flux in units of 10(48) s(-1) , P_7 is the pressure in units of 10(-7) dyn cm(-2) , and T_{HII,4} is the ion temperature in units of 10(4) K), are similar to those actually observed in UCHII regions. Similarly, ultracompact wind-driven bubbles can reach pressure equilibrium and the resulting final sizes are similar to those of UCHIIs. The same is true for a combined ultracompact structure consisting of an interior wind-driven cavity and an external HII region. For non-moving stars in a constant density medium, the lifetimes for all types of ultracompact objects only depend on the stellar lifetimes. For cases with a density gradient, depending on the core size and slope of the density distribution, some regions never reach the static equilibrium condition. A powerful dynamic instability appears when cooling is included in the neutral gas swept up by an HII region, or a combined wind-HII region structure. This instability was first studied by Giuliani (1979), and is associated with the thin-shell instability described by Vishniac (1983). The internal ionization front exacerbates the growth of the thin-shell instability, creating a rapid shell fragmentation, and our numerical simulations confirm the linear analysis of

  8. Triggered star formation associated with HII regions

    NASA Astrophysics Data System (ADS)

    Ogura, Katsuo

    There are two known mechanisms of triggered star formation associated with HII regions. One is the collect-and-collapse process of the shell accumulated around an expanding HII region, and the other is radiation-driven implosion (RDI) of bright-rimmed clouds (BRCs) originated from pre-existing cloud clumps. They are very briefly reviewed first. We then present the main results of our recent observations on the RDI star formation in BRCs. Finally, a third possible mechanism of triggering is suggested, which is attributed to the formation of elephant trunk-like structures due to hydrodynamical instability of ionization/shock fronts.

  9. Candidate Molecular Outflows from UC HII Regions

    NASA Astrophysics Data System (ADS)

    Shepherd, D. S.; Churchwell, E. B.

    1994-05-01

    Ultracompact (UC) HII regions surrounding deeply embedded O and B stars represent the earliest stages of massive star formation and evolution. Although much has been learned about the global properties of these active objects, we are far from understanding how massive stars form and how they impact their environments. A key to the early stages of massive star formation during the accretion/outflow phase has been the discovery that several UC HII regions (i.e. G5.89-0.39, DR 21, and W49) are at the center of massive, luminous molecular outflows. To further our understanding of the global properties of massive star evolution during this phase we must identify additional sources that are undergoing bipolar outflow. To address this issue we have performed a survey of UC HII regions to search for high velocity (12) CO(J = 1 - 0) line wings with the NRAO 12m telescope. Our results are presented here. Most of the sources observed show evidence for some high velocity gas in the wing profiles indicating that these sources are candidates for massive stars with bipolar molecular outflows. Nearly 25% of the observed sources show extreme high velocity (EHV) wings with full width zero intensity (FWZI) > 100 km s(-1) at the 50 mK level.

  10. Finding Distant Galactic HII Regions

    NASA Astrophysics Data System (ADS)

    Anderson, L. D.; Armentrout, W. P.; Johnstone, B. M.; Bania, T. M.; Balser, Dana S.; Wenger, Trey V.; Cunningham, V.

    2015-12-01

    The WISE Catalog of Galactic H ii Regions contains ˜2000 H ii region candidates lacking ionized gas spectroscopic observations. All candidates have the characteristic H ii region mid-infrared morphology of WISE 12 μ {{m}} emission surrounding 22 μ {{m}} emission, and additionally have detected radio continuum emission. We here report Green Bank Telescope hydrogen radio recombination line and radio continuum detections in the X-band (9 GHz; 3 cm) of 302 WISE H ii region candidates (out of 324 targets observed) in the zone 225^\\circ ≥slant {\\ell }≥slant -20^\\circ , | {\\text{}}b| ≤slant 6^\\circ . Here we extend the sky coverage of our H ii region Discovery Survey, which now contains nearly 800 H ii regions distributed across the entire northern sky. We provide LSR velocities for the 302 detections and kinematic distances for 131 of these. Of the 302 new detections, 5 have ({\\ell },{\\text{}}b,v) coordinates consistent with the Outer Scutum-Centaurus Arm (OSC), the most distant molecular spiral arm of the Milky Way. Due to the Galactic warp, these nebulae are found at Galactic latitudes >1° in the first Galactic quadrant, and therefore were missed in previous surveys of the Galactic plane. One additional region has a longitude and velocity consistent with the OSC but lies at a negative Galactic latitude (G039.183-01.422 -54.9 {km} {{{s}}}-1). With Heliocentric distances >22 kpc and Galactocentric distances >16 kpc, the OSC H ii regions are the most distant known in the Galaxy. We detect an additional three H ii regions near {\\ell }≃ 150^\\circ whose LSR velocities place them at Galactocentric radii >19 kpc. If their distances are correct, these nebulae may represent the limit to Galactic massive star formation.

  11. The Southern HII Region Discovery Survey: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Shea, Jeanine; Wenger, Trey; Balser, Dana S.; Anderson, Loren D.; Armentrout, William P.; Bania, Thomas M.; Dawson, Joanne; Miller Dickey, John; Jordan, Christopher; McClure-Griffiths, Naomi M.

    2017-01-01

    HII regions are some of the brightest sources at radio frequencies in the Milky Way and are the sites of massive O and B-type star formation. They have relatively short (< 10 Myr) lifetimes compared to other Galactic objects and therefore reveal information about spiral structure and the chemical evolution of the Galaxy. The HII Region Discovery Surveys (HRDS) discovered about 800 new HII regions in the Galactic longitude range -20 degrees to 270 degrees using primarily the Green Bank Telescope. Candidate HII regions were selected from mid-infrared emission coincident with radio continuum emission, and confirmed as HII regions by the detection of radio recombination lines. Here we discuss the Southern HII Region Discovery Survey (SHRDS), a continuation of the HRDS using the Australia Telescope Compact Array over the Galactic longitude range 230 to 360 degrees. We have reduced and analyzed a small sub-set of the SHRDS sources and discuss preliminary results, including kinematic distances and metallicities.

  12. The Spatial Distribution of HII Regions in Irregular Galaxies

    NASA Astrophysics Data System (ADS)

    Roye, E. W.; Hunter, D. A.

    1999-12-01

    CCD Hα and V-band images were used to examine the distributions of star-forming regions in 34 irregular galaxies, 29 of which are normal Ims and 6 of which are Blue Compact Dwarf (BCD)/starburst irregulars. The V-band images were used to determine the center, position angle, and inclination of the galaxies. The Hα images were used to trace the star-formation through the HII regions. HII region distributions in the planes of the galaxies were compared to turnovers in the rotation curves, the sizes of the galaxies, and locations relative to stellar bars. The overall symmetry and concentration of the HII distributions were also determined. In general, the HII regions are concentrated towards the centers of the galaxies, with the giant HII regions and complexes being even more centrally concentrated. Furthermore, most of the HII regions and complexes are located within R25, the radius at a B surface brightness of 25 magnitudes per arcsec2, as well as within the radius at which the rotation curve turns over. The locations of HII regions, giant HII regions, and complexes are not otherwise correlated with these particular radii. There are no obvious differences in the distribution of HII regions in BCDs and starburst galaxies relative to that of typical irregulars. However, in the two BCD/starburst galaxies for which rotation curves are available, both had HII complexes located well beyond the turnover in the rotation curve. There appears to be no preferential location of giant HII regions or complexes relative to stellar bars. Finally, the overall distribution of HII regions tends to be symmetric. I would like to thank the National Science Foundation for providing funding for the Research Experiences for Undergraduates program at Northern Arizona University, and Kathy Eastwood for directing the program.

  13. The GBT HII Region Discovery Survey: Galactic Structure

    NASA Astrophysics Data System (ADS)

    Balser, Dana S.; Anderson, Loren D.; Bania, Thomas M.; Wenger, Trey

    2015-01-01

    The HII region discovery survey (HRDS) has significantly expanded the census of HII regions in the Galaxy using the Green Bank Telescope (GBT). HII regions are the formation sites of massive OB stars and reveal the locations of current Galactic star formation. They are the archetypical tracers of spiral arms since, unlike other tracers, the identification of an HII region unambiguously locates massive star formation. Their chemical abundances indicate the present state of the ISM and reveal the elemental enrichment caused by the nuclear processing of many stellar generations. We determine kinematic distances in a self consistent way and explore Galactic structure across the Milky Way disk. In thermal equilibrium metal abundances are expected to set the nebular electron temperature with high abundances producing low temperatures. We derive the electron temperature using the radio recombination line-to-continuum ratio and use these values to explore metallicity structure.

  14. HII regions in dwarf irregular galaxies of the local group

    NASA Technical Reports Server (NTRS)

    Hodge, Paul; Lee, Myung Gyoon

    1990-01-01

    Deep, narrowband H alpha Charge Coupled Device (CCD) surveys of HII regions were carried out in several dwarf irregular galaxies in and near the local group. Data are now complete for these galaxies: NGC 6822, GR 8, IC 10, IC 1613, Sextans A, Sextans B, and Sag Irr. Observations are complete for DDO 47, 53, 167, 168 and 187. Details of some of the results for the surveys completed so far are discussed. For NGC 6822, CCD survey at H alpha resulted in the detection of 145 HII regions in the local group irregular galaxy NGC 6822. Most of them are newly detected, faint surface-brightness objects. Positions, maps and dimensions are being published elsewhere. For GR 8, a deep narrowband H alpha imaging of the nearby dwarf irregular galaxy GR 8 revealed a total of 32 HII regions. Positions, H alpha luminosities, and sizes of these objects were determined. The H alpha luminosity function has the same shape as that for more luminous galaxies, except for size of sample effects. Most HII regions detected are at the very low luminosity end of the general luminosity function. For IC 10, a deep CCD narrowband H alpha imaging of the local group dwarf irregular galaxy IC 10 revealed a total of 144 HII regions. Positions, H alpha luminosities, and sizes of these objects were determined. The H alpha luminosity function has the same shape as that for more luminous galaxies.

  15. Nonlinear Dynamics of Ionization Fronts in HII Regions

    SciTech Connect

    Mizuta, A; Kane, J O; Pound, M W; Remington, B A; Ryutov, D D; Takabe, H

    2006-04-20

    Hydrodynamic instability of an accelerating ionization front (IF) is investigated with 2D hydrodynamic simulations, including absorption of incident photoionizing photons, recombination in the HII region, and radiative molecular cooling. When the amplitude of the perturbation is large enough, nonlinear dynamics of the IF triggered by the separation of the IF from the cloud surface is observed. This causes the second harmonic of the imposed perturbation to appear on the cloud surfaces, whereas the perturbation in density of ablated gas in the HII region remains largely single mode. This mismatch of modes between the IF and the density perturbation in the HII region prevents the strong stabilization effect seen in the linear regime. Large growth of the perturbation caused by Rayleigh-Taylor-like instability is observed late in time.

  16. Formation of IR emission in HII regions around young stars

    NASA Astrophysics Data System (ADS)

    Pavlyuchenkov, Yaroslav; Kirsanova, Maria; Akimkin, Vitaly; Wiebe, Dmitry

    2013-07-01

    We investigate the formation of IR emission and corresponding intensity distributions at 8, 24, and 100 micron in HII regions around young massive stars. The evolution of an HII region is simulated using an advanced chemo-dynamical model. Three dust components are included in the model: large silicate grains, very small graphite grains (VSG), and polycyclic aromatic hydrocarbon (PAH) particles. The emergent SED and intensity distributions are calculated using our RT model where stochastic heating of VSG and PAHs is taken into account. The efficiency of two processes for stochastic heating of VSG and PAHs is studied: the absorption of star emission and interaction with hot gas. We compare the synthetic maps with the observed maps from Spitzer and Herschel for the RCW 120 HII region. It is shown that the model with constant PAH abundance cannot reproduce the ring-like appearance of the observed intensity distribution at 8 micron. In order to explain the observed IR distributions we inspect two models of dust evolution. The first model assumes that PAHs are destroyed inside an HII region. In the second model the drift of the dust particles caused by radiation pressure is taken into account. We show that the model with PAH destruction is consistent with observed profiles given appropriate choice of the PAH destruction time. On the contrary, the model with the dust drift is not consistent with observations.

  17. Anatomy of Starbursts in Extragalactic Giant HII Regions

    NASA Astrophysics Data System (ADS)

    Evans, Jessica

    2011-10-01

    Extragalactic giant HII regions {EGHRs} are sites of active, concentrated star formation, and thus provide excellent labs to analyze starburst phenomenon. Although they have been known for a long time, ground-based observations cannot resolve the physical structures and stellar content of EGHRs. The high resolution and sensitivity of Hubble Space Telescope {HST} are ideal for detailed studies of EGHRs. We have searched the Hubble Legacy Archives {HLA} and found 17 nearby galaxies, within 15 Mpc, with H-alpha and continuum images. We propose to use these images to study the three top-ranking HII regions in each galaxy. While these 51 HII regions span a range in luminosity, most of them are bonafide EGHRs, with H-alpha luminosity greater than a few times 10^39 ergs/s. We will use the H-alpha image to study the distribution and physical structure of the gas in each HII region and determine its H-alpha luminosity and required ionizing flux. We will use the continuum images to determine whether concentrated clusters or distributed OB associations reside in these HII regions, and use photometric measurements to determine the mass and age spread of the resolved stellar population. These will then be compared with the interstellar structures. The results will help us understand the starburst phenomenon and answer questions such as: Are globular clusters formed in EGHRs? How does star formation proceed in an EGHR? How does the physical structure of an EGHR relate to the luminosity, physical location in the host galaxy, and the host galaxy type?

  18. The Ultraviolet Emission Spectra of AN HII Region

    NASA Astrophysics Data System (ADS)

    Cox, Nancy

    1991-07-01

    ONE OF THE ADVANTAGES OF THE NEW INSTRUMENTS SUCH AS THE HUBBLE SPACE TELESCOPE IS TO BE ABLE TO STUDY THE UNIVERSE AT WAVELENGTHS PREVIOUSLY UNOBSERVABLE FROM UNDER THE EARTH'S ATMOSPHERE. ONE THE THESE IS THE UV REGION OF THE STECTRUM. USING HST'S FOS, I WOULD LIKE TO TAKE A UV SPETRUM OF AN HII REGION, M8, THE LAGOON NEBULA (HOURGLASS REGION). HII REGIONS ARE AREAS OF STARBIRTH AND ARE SAMPLES OF THE INTERSTELLAR MATTER OUT OF WHICH STARS ARE BEING BORN. HOT, YOUNG O STARS WHICH RADIATE STRONGLY IN THE UV ARE EMBEDDED IN M8. MANY EMSSION LINES ARE EXPECTED BETWEEN 912-3300 ANGTROMS. USING WF/PC, AN IMAGE OF THE HOURGALSS WILL BE TAKEN LOOKING FOR FILIMENTARY STRUCTURE AND NEW BORN STARS.

  19. Drama of HII regions: Clustered and Triggered Star Formation

    NASA Astrophysics Data System (ADS)

    Li, Jinzeng; YUAN, Jinghua; LIU, Hongli; Wu, Yuefang; Huang, Yafang

    2015-08-01

    Intense ultraviolet radiation from young massive stars ionizes ambient material leading to the formation of HII regions which have keen impact upon the birth of new stars in the vicinities. The strong radiation may be responsible for the dispersal of molecular clouds to hinder star formation, while the expansion of HII regions would collect neutral material to form dense layers which may be gravitationally unstable to collapse to give birth to new stars.In order to understand the star formation process under the influence of HII regions, we have carried out extensive investigations to well selected star-forming regions which all have been profoundly affected by existing massive O type stars. On the basis of multi-wavelength data from mid-infrared to millimeter collected using Spitzer, Herschel, and ground based radio telescope, the physical status of interstellar medium and star formation in these regions have been revealed. Clustered and sequential star formation have been detected toward well known HII regions, such as IC1396 and Sh-155. In a relatively large infrared dust bubble, active star formation is undergoing and the shell is still expanding. Socked features and signs of triggered star formation have been tentatively detected in a relatively small bubble. The dense cores in the Rosette Molecular Complex detected at 1.1 mm using SMA have been speculated to have a likely triggered origin according to their spatial distribution. Although some observational results have been obtained, more efforts are necessary to reach trustworthy conclusions. And more regions will be extensively explored based on multi-wavelength observations, especially the data collected using the Herschel Space Observatory.

  20. Single Star HII Regions in nearby LEGUS Galaxies

    NASA Astrophysics Data System (ADS)

    Kayitesi, Bridget; Lee, Janice C.; Thilker, David A.; LEGUS Team

    2017-01-01

    It is believed that O stars typically form in clustered environments, however past observations have shown that there are a few O stars in the field that are fairly far from clusters and have low space velocities. The goal of this project is to determine whether these O stars can be born in situ or whether they are runaways ejected from their parent clusters due to binary supernova explosions or other dynamic interactions. To do this, we select candidate hot stars and compute an isolation metric based on distance from other hot stars and clusters. We then deploy Zooniverse citizen scientists to classify the isolated sources and their associated nebulae. The detected presence of an HII region allows us to confirm a candidate as a true O star. We use the Zooniverse classification system to study the morphology of these HII regions and determine the runaway status of the O stars.

  1. Realistic Models for Filling Factors in HII Regions

    NASA Astrophysics Data System (ADS)

    Spangler, Steven R.; Costa, Allison H.; Bergerud, Brandon M.; Beauchamp, Kara M.

    2017-01-01

    One of the parameters used to describe HII regions and other ionized parts of the interstellar medium is the filling factor, defined as the volume fraction of an HII region occupied by matter. The best observational evidence for the existence of a filling factor less than unity is a discrepancy between the electron density derived from density-sensitive line ratios and the root mean square density obtained from emission measure measurements. Following the early, influential study by Osterbrock and Flather (ApJ 129, 26, 1959), most investigations of HII regions envision these objects as a group of isolated cells of high gas density embedded in a vacuum. This picture is at serious odds with more direct measurements of other astrophysical plasmas like the solar wind, where the density follows a less extreme probability distribution function (pdf) such as an exponential or lognormal. We have carried out a set of simulations in which model HII regions are created with different density pdfs such as exponential and lognormal as well as the extreme case of two delta functions. We calculate the electron density as inferred from spectroscopic line ratios and emission measures for all lines of sight through the model nebulas. In the cases of exponential and lognormal pdfs, the spectroscopically derived densities are higher than those obtained by the emission measures by factors of 20 to 100 percent. These are considerably smaller than values often reported in the literature, which can be an order of magnitude or greater. We will discuss possible ways to reconcile realistic density pdfs such as measured in space and laboratory plasmas with the results from astronomical spectroscopic measurements. Finally, we point out that for the Orion Nebula, the density discrepancy is due to geometry, not filling factor (O'Dell, ARAA 39, 99, 2001).

  2. Anatomy of Starbursts in Extragalactic Giant HII Regions

    NASA Astrophysics Data System (ADS)

    Evans, Jessica Marie; Chu, You-Hua

    2013-06-01

    Extragalactic giant HII regions (EGHRs) are sites of active, concentrated star formation, and thus provide excellent labs to analyze the starburst phenomenon. Although they have been known for a long time, ground-based observations cannot resolve the physical structures and stellar content of EGHRs. The high resolution and sensitivity of Hubble Space Telescope (HST) are ideal for detailed studies of EGHRs. We have searched the Hubble Legacy Archives (HLA) and found > 10 nearby galaxies, within 20 Mpc, with H-α and continuum images. To determine the best methods for analyzing these data, we perform an in-depth analysis of the EGHRs in M51. M51 is a face-on spiral galaxy 8.4 Mpc away, with well-resolved multi-wavelength observations in the HLA. We sample the 20 most luminous HII regions in M51, and the top three in several other galaxies, many of which are bonafide EGHRs with an H-α luminosity > 10^{39} ergs s^{-1}. We use the H-α image to study the distribution and physical structure of the gas in each HII region and determine its H-α luminosity and required ionizing flux. We use the continuum images to determine whether super stellar clusters (SSCs) are found in these HII regions, and use photometric measurements to determine the mass and age spread of the resolved stellar population. These are then compared with the interstellar structures. The results help us provide the groundwork for studying EGHRs in multiple galaxies and elucidate the starburst phenomenon by investigating questions such as: What role does environment play in the formation of EGHRs? How do EGHRs evolve? How does star formation proceed in an EGHR?

  3. Revealing of HII-regions in Galaxies with Panoramic Spectroscopy

    NASA Astrophysics Data System (ADS)

    Hakopian, S. A.; Balayan, S. K.

    2016-06-01

    Observations intended to investigation and revealing of nodes of processes of nuclear and starforming activity in galaxies were performed via panoramic spectroscopy. Data obtained on Mrk 1050 revealed evidence of starforming activity also outside the central engine of high surface brightness. Two small HII-regions, being likely a part of the chain, are located in the part of the spiral branch coming from the nucleus part.

  4. Dust continuum spectra from model HII regions

    NASA Technical Reports Server (NTRS)

    Aannestad, P. A.; Emery, R. J.

    1989-01-01

    The infrared spectrum emitted by nebular dust, heated by the ionizing stars in H II blisters and spherical H II regions, is calculated for various model parameters. Absorption of the non-ionizing radiation in a neutral layer is included. Heating by the Lyman alpha photon field is taken into account. The dust is composed of silicate and graphite grains, and evaporation of the grains in the inner region is considered. The models are presented with a view to interpretation of infrared observations of dusty H II regions and can be applied directly to the infrared astronomy satellite survey data. The continuum emission is compared with calculated fine structure line emission.

  5. Dust continuum spectra from model HII regions

    NASA Technical Reports Server (NTRS)

    Aannestad, P. A.; Emery, R. J.

    1989-01-01

    The infrared spectrum emitted by nebular dust, heated by the ionizing stars in H II blisters and spherical H II regions, is calculated for various model parameters. Absorption of the non-ionizing radiation in a neutral layer is included. Heating by the Lyman alpha photon field is taken into account. The dust is composed of silicate and graphite grains, and evaporation of the grains in the inner region is considered. The models are presented with a view to interpretation of infrared observations of dusty H II regions and can be applied directly to the infrared astronomy satellite survey data. The continuum emission is compared with calculated fine structure line emission.

  6. Line Profile Shapes in Optical HII Regions

    NASA Astrophysics Data System (ADS)

    Yorke, H. W.

    1984-09-01

    Some of the most spectacular astronomical photographs and favourite subjects for popular astronomical slide shows are colour pictures of H 11 regions. Probably every astronomer, both amateur and professional, is familiar with the nebula in Orion, M 42. Shaped like an opened fan, this well-known H I1 region ("H II" is the technical term for ionized hydrogen) appears to be yellow in its bright core and fades out to red and then a faint bluish hue towards the outer perimeter. Of course, the exact colours and size of the Orion Nebula, M 42, is dependent on the type of colour film used and the amount of light gathered. Longer exposure times tend to make the nebula appear larger, expanding outward in the direction of the fan's perimeter. Short exposures of the nebula (or using the eye instead of film) reveal the presence of four bright stars in its core, the "Trapezium", so named because of their relative geometrical positions. These stars cannot be seen on longexposure pictures, because the light from the nebular core saturates the film.

  7. Relic HII regions and radiative feedback at high redshifts

    NASA Astrophysics Data System (ADS)

    Mesinger, Andrei; Bryan, Greg L.; Haiman, Zoltán

    2009-11-01

    Ultraviolet (UV) radiation from early astrophysical sources could have a large impact on subsequent star formation in nearby protogalaxies, and in general on the progress of cosmological reionization. Theoretical arguments based on the absence of metals in the early Universe suggest that the first stars were likely massive, bright, yet short-lived, with lifetimes of a few million years. Here we study the radiative feedback arising from such stars using hydrodynamical simulations with transient UV backgrounds (UVBs) and persistent Lyman-Werner backgrounds (LWBs) of varying intensity. We extend our prior work in Mesinger et al., by studying a more typical region whose protogalaxies form at lower redshifts, z ~ 13-20, in the epoch likely preceding the bulk of reionization. We confirm our previous results that feedback in the relic HII regions resulting from such transient radiation is itself transient. Feedback effects dwindle away after ~30 per cent of the Hubble time, and the same critical specific intensity of JUV ~ 0.1 × 10-21ergs-1cm-2Hz-1sr-1 separates positive and negative feedback regimes. This suggests that overall feedback is fairly insensitive to the large-scale environment, overdensity and redshift-dependent halo parameters, and can accurately be modelled in this regime with just the intensity of the impinging UVB. Additionally, we discover a second episode of eventual positive feedback in haloes which have not yet collapsed when their progenitor regions were exposed to the transient UVB. When exposed to the transient UVB, this gas suffers relatively little density depletion but a significant enhancement of the molecular hydrogen abundance, thus resulting in net positive feedback. This eventual positive feedback appears in all runs, regardless of the strength of the UVB. However, this feedback regime is very sensitive to the presence of Lyman-Werner radiation, and notable effects disappear under fairly modest background intensities of JLW >~ 10-3 × 10

  8. The Evolution of Dust and Infrared Radiation in HII Regions

    NASA Astrophysics Data System (ADS)

    Topchieva, A.; Wiebe, D.; Kirsanova, M.; Krushinsky, V.

    2017-06-01

    Regions of ionized hydrogen are often observed in infrared (IR) emission as ring-like nebulae. IR emission presumably comes from hot dust embedded in ionized gas and surrounding the ionized gas. The dust within these regions is believed to be partially blown away by the action of both the stellar wind and radiation pressure from young massive stars. We investigate trends in morphology of IR ring nebulae representing HII regions. Archival data from VLA New GPS 20 cm survey as well as from Spitzer GLIMPSE and MIPSGAL surveys at 8 and 24 micron are utilized to select visually objects with more or less regular shapes. We have identified 92 HII regions surrounded by closed or nearly closed IR rings. Shapes of these rings are characterized by fitting ellipses in order to estimate their orientation and oblateness. From our catalogue of 92 objects we have selected 27 objects with eccentricities of fitted ellipses less than 0.3. These objects are suggested as prototype targets for 1D hydrodynamic modeling.

  9. Measuring Magnetic Fields in Photoionized Interstellar Plasmas (HII Regions)

    NASA Astrophysics Data System (ADS)

    Spangler, Steven; Costa, Allison

    2015-11-01

    Hot luminous stars photoionize the interstellar gas around them, creating plasmas with a very high ionization fraction. In astronomical terminology, these are called HII regions. They are dynamic plasmas, expanding due to overpressure with respect to the interstellar medium. We are making diagnostic measurements to determine the strength and structure of magnetic fields in these objects. This paper presents our results on the Rosette Nebula. We diagnose the magnetic field in the Rosette by measurements of Faraday rotation on lines of sight passing through the nebula. These measurements are made with the Very Large Array radio telescope of the National Radio Astronomy Observatory. We have measurements of the rotation measure for 18 lines of sight. Values of the mean, line of sight component of the magnetic field range from about 3 to 5 microGauss. We will discuss comparison of these measurements with models for modification of the interstellar magnetic field by an HII region. This work was supported by grants AST09-07911 and ATM09-56901 from the National Science Foundation.

  10. VLBI astrometry toward Sgr D HII region with VERA

    NASA Astrophysics Data System (ADS)

    Sakai, Daisuke; Oyama, Tomoaki; Nagayama, Takumi; Honma, Mareki; Kobayashi, Hideyuki

    2017-01-01

    The Galactic centre region shows outstanding non-circular motion unlike the Galactic disk. As scenarios describing this non-circular motion, resonance orbits formed by the Galactic bar potential or expanding motion by past activity of the central BH are proposed. However, these both scenarios are based on line-of-sight velocities of molecular clouds in this region, and such one-dimension velocity information is insufficient to separate these scenarios. To reveal dynamics of the Galactic centre region, we conducted astromertic observations of 22 GHz water maser sources toward the Galactic centre direction. We conducted astrometric observations toward water maser source associated with Sgr D HII region. As a result, we succeeded to measure the parallax and proper motion of the maser source. The measured distance was 2.36(+0.58/-0.39) kpc. This result clearly indicates that this source is not associated with the Galactic centre, but located on the Galactic disk.

  11. Differences in the size-internal velocity relation of galactic and extragalactic HII regions

    NASA Technical Reports Server (NTRS)

    Odell, C. R.

    1990-01-01

    The nature of the size-internal velocity relation in extragalactic HII regions is examined in order to improve their use as distance determinants. The relation between the linear size and the internal velocity was compared for HII regions in the Galaxy and in external galaxies. Data for the former are from the researcher's own studies at high spatial resolution, while the latter have been the subject of spectroscopy that includes almost the entire objects. The Galactic HII regions are corrected to values of the internal velocity that would be observed if they were at extragalactic distances. A very different size-internal velocity relation was found for the two types of objects in the sense that the extragalactic objects are some ten times larger at the same internal velocity. This is interpreted to mean that the extragalactic HII regions are actually complexes of small HII regions comparable in size to their Galactic counterparts.

  12. HII regions evolution: by using POPSTAR evolutionary synthesis models

    NASA Astrophysics Data System (ADS)

    Mollá, M.; Martín-Manjón, M.; García-Vargas, M.

    2011-11-01

    We show the results from a series of papers where we present the POPSTAR evolutionary synthesis models. The ionizing Spectral Energy Distributions (SEDs) are those obtained by the POPSTAR code (Mollá et al. 2009, MNRAS, 398, 451) for 6 different metallicities, with a very low metallicity set, Z=0.0001, not included in previous similar works. We compute the synthetic emission line spectra of HII regions ionized by young star clusters by combining the cluster SEDs with the photoionization code CLOUDY, for 7 values of the cluster mass and ages ranging between 0.1 and 5.2 Myr (Martín-Manjón et al. 2010, MNRAS, 403, 2012). We assume that the radius of each HII region is the distance at which the ionized gas is deposited by the action of the mechanical energy of massive star winds and supernovae from the central ionizing young cluster. This allows us to eliminate the ionization parameter u as a free argument, since now its value is set from the cluster physical properties (mass, age and metallicity) and from the chemical gas properties (hydrogen density and abundances). Finally we calculate the contribution of these emission lines to the broad band colors (García-Vargas et al. 2010, in prep.). The color-color diagram are strongly affected, and consequently the interpretation of stellar properties from photometrical observations. All products are available in the VO, in the VizieR On-line Data Catalog: J/MNRAS/398/451 and in the FRACTAL web page http://www.fractal-es.com.

  13. Hydrodynamic Instability of Ionization Fronts in HII Regions

    NASA Astrophysics Data System (ADS)

    Mizuta, Akira; Kane, Jave; Remington, Bruce; Ryutov, Dmitri; Takabe, Hideaki

    2003-10-01

    The complex dynamics of an ionization front which is a surface of radiatively driven molecular cloud is a common feature of HII regions. We carried out two-dimensional numerical hydrodynamic simulations with a realistic initial density profile for a neutral gas region, and with perturbations at the ionization front considering detailed physics so far. The energy deposition and release due to the absorption of strong UV radiation from O-stars the recombination effects in the ionized region are included. The radiation loss from shocked molecular gas is also included. We introduce magnetic field's effect into the equation of state to prevent too high density because of radiative collapse in the molecular gas^a. The results are compared with recent detailed observational data of the Eagle Nebula by the Hubble Space Telescope (HST) and Berkeley-Illinois-Maryland Array (BIMA)^b,c. We also discuss the growth of the perturbations at the ionization front and the appropriateness of hydrodynamic instabilities on the ionized front. a. Ryutov, D, & Remington, B., Plasma Phys. Control. Fusion (2002) 44, B407, b. Hester, J. J, et al., AJ (1996) 111, 2349, c. Pound, M. W., et al., ApJ (1998) 493, L113

  14. 870 μm continuum observations of the bubble-shaped nebula Gum 31

    NASA Astrophysics Data System (ADS)

    Duronea, N. U.; Vasquez, J.; Gómez, L.; Cappa, C. E.; Firpo, V.; López-Caraballo, C. H.; Rubio, M.

    2015-10-01

    Aims: We present here a study of the cold dust in the close environs of the ring nebula Gum 31. We aim at deriving the physical properties of the molecular gas and dust associated with the nebula, and investigating its correlation with the star formation in the region, which was probably triggered by the expansion of the ionization front against its environment. Methods: We make use of 870 μm emission data obtained with the Large APEX Bolometer Camera (LABOCA) to map the dust emission. The 870 μm emission provides an excellent probe of mass and density of dense molecular clouds. The obtained LABOCA image was compared to archival infrared, radio continuum, and optical images. Results: The 870 μm emission follows the 8 μm (Spitzer), 250 μm, and 500 μm (Herschel) emission distributions showing the classical morphology of a two-dimensional projection of a spherical shell. We use the 870 μm and 250 μm images to identify 60 dust clumps in the collected layers of molecular gas using the Gaussclumps algorithm. The clumps have effective deconvolved radii between 0.16 pc and 1.35 pc, masses between 70 M⊙ and 2800 M⊙, and volume densities between 1.1 × 103 cm-3 and ~2.04 × 105 cm-3. The total mass of the clumps is ~37 600 M⊙. The dust temperature of the clumps is in the range from 21 K to 32 K, while inside the Hii region it reaches ~40 K. The clump mass distribution for the sample is fitted by a power law dN/dlog (M/M⊙) ∝ M- α, with α = 0.93 ± 0.28. The slope differs from those obtained for the stellar IMF in the solar neighborhood, suggesting that the clumps are not direct progenitors of single stars/protostars. The mass-radius relationship for the 41 clumps detected in the 870 μm emission shows that only 37% of them lie in or above the high-mass star formation threshold. Most of this 37% have candidate YSOs projected inside their limits. A comparison of the dynamical age of the Hii region with the fragmentation time, allowed us to conclude that the

  15. New Measurements of the ^4He Abundance in Galactic HII Regions

    NASA Astrophysics Data System (ADS)

    Cioni, M. R.; Cortiglioni, S.; Orsini, M.; Palazzi, E.; Palumbo, G. G. C.; Sorochenko, R. L.; Tsivilev, A. P.

    Preliminary results of the ^4He relative abundance determination from Radio Recombination Lines observations at different frequencies in the Orion, Rosette and W3 HII regions are presented. The Orion HII region has been mapped at both 22 GHz and 36 GHz with the same beamwidth (2 arcmin) using the Medicina and Puschino radio telescopes respectively. The RRLs parameters, together with their variation with frequency and with distance were determined by centering the map on the star theta^1Ori C. Three positions were observed in the Rosette HII region at 8.3 GHz leading to the first detection in this region of the transition He92alpha . The derived ^4He relative abundance is considerably greater than the ones obtained from previous measurements. The W3 HII region was observed at 36 GHz and the ^4He/H value derived was compared with previous measurements performed with higher spatial resolution.

  16. Hα line profiles for a sample of supergiant HII regions. II. Broad, low intensity components

    NASA Astrophysics Data System (ADS)

    Rozas, M.; Richer, M. G.; López, J. A.; Relaño, M.; Beckman, J. E.

    2006-08-01

    We analyze the broad, low intensity, high velocity components that are seen in the Hα line profiles for a sample of HII regions. These HII regions are chosen from among the brightest and most isolated in a sample of spiral galaxies for which we have photometric and spectroscopic data: NGC 157, NGC 3631, NGC 6764, NGC 3344, NGC 4321, NGC 5364, NGC 5055, NGC 5985, and NGC 7479. We confirm that the line profiles of most of these bright, giant extragalactic HII regions contain broad kinematic components of low intensity, but high velocity, that we denote as wings. We analyze these components, deriving emission measures, central velocities, and velocity dispersions of the blue and red features, which are similar. We interpret these components as expanding shells within the HII regions and produced by the stellar winds from the ionizing stars. We compare the kinetic energies of these expanding shells with the kinetic energy available from the stellar winds. If we allow for the hypothesis that the brightest HII regions are density bounded, we show that, for these HII regions, the stellar wind mechanism can explain the observed shell kinetic energies.

  17. An outflow linked to a YSO in Gum 31?

    NASA Astrophysics Data System (ADS)

    Vazzano, M. M.; Cappa, C. E.; Bosch, G.; Vásquez, J.

    2016-08-01

    We analyze the distribution of the molecular gas associated with 10349-5824, a young stellar object located on the edge of the H ii region Gum31, with the aim of investigating the existence of bipolar outflows. We use CO(2-1) line observations obtained with the APEX telescope, H line observations on the K band taken with Flamingos 2 in Gemini South and additional data from at 4.5, 8 and 24 m. J103648.97-584010.7 (1), classified as class II, coincides with extended emission in 4.5 m, suggesting the presence of bipolar flows, and with H emission at 2.12 m. Three extended sources detected in H at 0.5 and 1.5 of 1 could also suggest the presence of shocked gas. Additional evidence of bipolar outflows comes from CO(2-1) spectra.

  18. Deuteration around the ultracompact HII region Monoceros R2

    NASA Astrophysics Data System (ADS)

    Treviño-Morales, S. P.; Pilleri, P.; Fuente, A.; Kramer, C.; Roueff, E.; González-García, M.; Cernicharo, J.; Gerin, M.; Goicoechea, J. R.; Pety, J.; Berné, O.; Ossenkopf, V.; Ginard, D.; García-Burillo, S.; Rizzo, J. R.; Viti, S.

    2014-09-01

    Context. The massive star-forming region Monoceros R2 (Mon R2) hosts the closest ultra-compact Hii region, where the photon-dominated region (PDR) between the ionized and molecular gas can be spatially resolved with current single-dish telescopes. Aims: We aim at studying the chemistry of deuterated molecules toward Mon R2 to determine the deuterium fractions around a high-UV irradiated PDR and investigate the chemistry of these species. Methods: We used the IRAM-30 m telescope to carry out an unbiased spectral survey toward two important positions (namely IF and MP2) in Mon R2 at 1, 2, and 3 mm. This spectral survey is the observational basis of our study of the deuteration in this massive star-forming region. Our high spectral resolution observations (~0.25-0.65 km s-1) allowed us to resolve the line profiles of the different species detected. Results: We found a rich chemistry of deuterated species at both positions of Mon R2, with detections of C2D, DCN, DNC, DCO+, D2CO, HDCO, NH2D, and N2D+ and their corresponding hydrogenated species and rarer isotopologs. The high spectral resolution of our observations allowed us to resolve three velocity components: the component at 10 km s-1 is detected at both positions and seems associated with the layer most exposed to the UV radiation from IRS 1; the component at 12 km s-1 is found toward the IF position and seems related to the foreground molecular gas; finally, a component at 8.5 km s-1 is only detected toward the MP2 position, most likely related to a low-UV irradiated PDR. We derived the column density of the deuterated species (together with their hydrogenated counterparts), and determined the deuterium fractions as Dfrac = [XD]/[XH]. The values of Dfrac are around 0.01 for all the observed species, except for HCO+ and N2H+, which have values 10 times lower. The values found in Mon R2 are similar to those measured in the Orion Bar, and are well explained with a pseudo-time-dependent gas-phase model in which

  19. Extraplanar HII regions in the edge-on spiral galaxies NGC 3628 and NGC 4522

    NASA Astrophysics Data System (ADS)

    Stein, Y.; Bomans, D. J.; Ferguson, A. M. N.; Dettmar, R.-J.

    2017-08-01

    Context. Gas infall and outflow are critical for determining the star formation rate and chemical evolution of galaxies but direct measurements of gas flows are difficult to make. Young massive stars and Hii regions in the halos of galaxies are potential tracers for accretion and/or outflows of gas. Aims: Gas phase abundances of three Hii regions in the lower halos of the edge-on galaxies NGC 3628 and NGC 4522 are determined by analyzing optical long-slit spectra. The observed regions have projected distances to the midplane of their host from 1.4 to 3 kpc. Methods: With the measured flux densities of the optical nebular emission lines, we derived the oxygen abundance 12 + log(O/H) for the three extraplanar Hii regions. The analysis was based on one theoretical and two empirical strong-line calibration methods. Results: The resulting oxygen abundances of the extraplanar Hii regions are comparable to the disk Hii regions in one case and are a little lower in the other case. Since our results depend on the accuracy of the metallicity determinations, we critically discuss the difference of the calibration methods we applied and confirm previously noted offsets. From our measurements, we argue that these three extraplanar Hii regions were formed in the disk or at least from disk material. We discuss the processes that could transport disk material into the lower halo of these systems and conclude that gravitational interaction with a companion galaxy is most likely for NGC 3628 while ram pressure is favored in the case of NGC 4522. Based on observations gathered as part of observing program 64.N-0208(A), 3.6 m telescope with European Southern Observatory (ESO) Faint Object Spectrograph and Camera (EFOSC2) at ESO, La Silla observatory.

  20. Continuing the Search for Flickering Ultracompact HII Regions: EVLA Observations of W49A

    NASA Astrophysics Data System (ADS)

    De Pree, Christopher G.; Melo, Theresa; Mac Low, Mordecai-Mark; Wilner, David J.; Goss, Miller; Galvan-Madrid, Roberto

    2017-01-01

    Recent observations of the Galactic Center massive star forming region Sgr B2 indicate that approximately 5% of the ultracompact (UC) HII regions detected there have changed significantly in flux density over a 20 year period (De Pree et al. 2014, 2015). One explanation of these changes in flux density is provided by a massive star formation model in which accretion proceeds through the early formation of UC HII regions, causing the regions to change in brightness (“flicker”) on short timescales. To search for flickering in another Galactic star forming region, we have recently used the EVLA (2015-16) to make a multi-configuration image of the W49A region (D~11.5 kpc). We present 8.309 GHz images from the A+B+C configuration data to compare to images with the same frequency, bandwidth and resolution made with the VLA in 1996. We also present an A+B+C+D configuration image with higher spatial resolution and sensitivity than the 1996 data. We present these initial continuum images and H92α radio recombination line (RRL) spectra from selected UC HII regions. This study is part of an ongoing campaign to search for variability in UC HII regions, as predicted by models of unsteady accretion flows (Peters et al. 2010).

  1. VizieR Online Data Catalog: Emission lines from giant HII regions (Garcia Vargas+, 1995)

    NASA Astrophysics Data System (ADS)

    Garcia Vargas, M. L.; Bressan, A.; Diaz, A. I.

    1995-03-01

    We have computed theoretical models of the emission line spectra of giant extragalactic HII regions (GEHR) in which a single star cluster is assumed to be responsible for the ionization. In this paper we present the synthetic emission line spectra of the ionized regions. (1 data file).

  2. The Transition from Hot Cores to Ultracompact HII Regions: Results of Centim eter and Millimeter Interferometry

    NASA Astrophysics Data System (ADS)

    Kurtz, S.; Carral, P.; Shepherd, D.; Hofner, P.; Rodriguez, L. F.

    1998-11-01

    We present the results of continuum, molecular line, and radio recombination line studies of massive star-forming regions made with the VLA and OVRO interferometers. We discuss the results in terms of the early development of massive stars, in particular the hot core and ultracompact HII region phases, and the possible transition from one phase to the other.

  3. Molecular cloud/HII region interfaces in the star forming region NGC 6357.

    NASA Astrophysics Data System (ADS)

    Massi, F.; Brand, J.; Felli, M.

    1997-04-01

    We have performed ^12^CO(1-0), ^12^CO(2-1), ^13^CO(1-0), ^13^CO(2-1), C^18^O(1-0), C^18^O(2-1), HCO^+^(1-0) and H^13^CO^+^(1-0) observations towards two selected areas in the star forming complex NGC 6357 with angular resolutions from 21" to 55". In particular, we have mapped the molecular gas around the two HII regions G353.1+0.6 and G353.2+0.9 in the ^12^CO(1-0) and ^13^CO(1-0) transitions with a resolution of ~43". This improves on the coarser ^12^CO(1-0) observations previously carried out by others. We have also studied the physical properties of gas along strips through the molecular cloud/HII region interfaces. For G353.1+0.6, the observations confirm that an ionization front is eroding a warm, dense molecular cloud located to the north of the optical nebula. The molecular gas appears fragmented on a scale size >0.5pc and not all the components are related to the HII region. There is evidence of a density increase near the front and indications of temperature gradients toward the exciting stars. This is further suggested by the presence of ^12^CO(1-0) self-absorption produced by a cooler external layer. The isotopic ratio X(^13^CO)/X(C^18^O) decreases from the inner part of the clouds towards the front, contrary to what is theoretically predicted and observed in many other regions. This may be due to excitation or optical depths effects. An evolutionary scenario is proposed where the exciting stars form at the edge of a molecular cloud. The morphology of G353.2+0.9 is rather different from what previously believed. Only a weak "bar" of molecular material was found to the south of the sharp ionization front observed optically and in the radio-continuum, and most of the molecular emission arises from regions behind or to the north of the HII region. This indicates that we are viewing a late stage "blister" configuration face-on. This region is fragmented on a scale size >0.5pc, and a warm, dense and compact molecular fragment coincides with the elephant trunk

  4. Dust content in compact HII regions (NGC 7538-IRS1, IRS2, and IRS3)

    NASA Astrophysics Data System (ADS)

    Akabane, K.; Kuno, N.

    2005-02-01

    The luminosity of the central star of the compact HII regions of NGC 7538 was estimated from the solid angle of the IR sources subtended relative to the central star, and was found to be 5˜ 10 times as intense as that of IR sources. Under the single central star approximation, the luminosity gives a stellar UV photon rate NU(*) (s-1) of ˜3.0 × 1048, ˜1.5 × 1049, ˜5.1 × 1049, and ˜1.7 × 1047 for the compact HII regions of NGC 7538-IRS1(A/2), B, IRS2, and IRS3, respectively. NU (*) and the observed electron density, ne, provide the dust opacity of the ionizing photon, τSd, for the optical path out to the Strömgren sphere radius rS, assuming a gas with standard dust content. Ionizing photon opacity over the same optical path but with the actual dust content τSda is also derived from ri / rS, where ri is the radius of the ionized sphere, which is estimated from NU(*) and the observed volume emission measure ne2 (4 π ri3/3) (Spitzer \\cite{Spitzer1978}). An observational trend of γ NU(*) / 4π ri2 1/2 ˜ constant, where γ = τSda / τSd}, was obtained for the 4 compact HII regions of the NGC 7538(N). Fourteen selected compact HII regions from data catalogued by VLA observations were examined for this trend, and a similar result was obtained. A limit of γ as 15 ≥ γ ≥ 0.1 was given for the 14 selected sources. The size of the dust-depleted cavity of the NGC 7538(N) suggested by Chini et al. (\\cite{Chini1986}) coincides with that of the ionized sphere of the IRS2 of the region.

  5. Anomalous Microwave Emission in HII regions: is it really anomalous? The case of RCW 49

    NASA Astrophysics Data System (ADS)

    Paladini, Roberta; Ingallinera, A.; Agliozzo, C.; Tibbs, C.; Dickinson, C.; Trigiglio, C.; Umana, G.; Noriega-Crespo, A.; Flagey, N.

    2014-01-01

    The detection of an excess of emission at microwave frequencies with respect to the predicted free-free emission is reported for several Galactic HII regions. Here, we investigate the case of RCW 49, the brightest Galactic HII region of the Southern hemisphere, for which the Caltech Background Imager (CBI) tentatively 3 sigma) detected Anomalous Microwave Emission at 31 GHz. Using the Australia Telescope Compact Array (ATCA), we carried out continuum multi-frequency observations (5 GHz, 19 GHz and 34 GHz) of an area of 7.8' X 5.6' centered on the CBI 31-GHz peak of emission, complemented by observations of the H109alpha hydrogen Radio Recombination Line of the same region. The analysis of the continuum and line data show that: 1) the microwave-IR correlation found by the Caltech Background Imager on scales of ~ 6' appears to persist on arcsec angular scales (0.4'' - 1'); 2) there is evidence of rising spectral indices between 1.4 and 5 GHz and these are compatible with the presence of strong stellar winds, possibly generated by the Westerlund 2 cluster; 3) the anomalous emission in RCW 49 cannot be attributed to inverted free-free associated with Ultra Compact HII regions. Finally, we propose that what is observed in RCW 49 might not be specific of this HII region only, and that the excess of microwave emission in this type of sources might not have an "anomalous" origin, but rather simply be ascribed to stellar winds and/or shocks phenomena.

  6. The Radio and IR Luminosity Function of compact Galactic HII regions

    NASA Astrophysics Data System (ADS)

    Paladini, R.; De Zotti, G.; Noriega-Crespo, A.; Carey, S. J.

    2009-01-01

    We present the radio luminosity function (LF) of compact Galactic HII regions, derived by using ˜ 200 sources from the recombination line survey by Caswell & Haynes (1987). The data set is complete for Speak > 1.3 Jy at 5 GHz, corresponding to an integrated flux density of ˜ 3 Jy. The LF is reconstructed by means of a generalized Schmidt's estimator which takes into account the actual spatial distribution of the HII regions along the plane of the Galaxy. The resulting LF is described by a two-component power-law, with a cut-off at log L(α) = ˜ 38.3 erg/sec. This work will be complemented with the derivation, by means of the MIPSGAL data set, of the IR counterpart of the radio LF here presented. An extension of this work will consist in deriving the IR counterpart of the radio LF here obtained, by making use of the MIPSGAL data set.

  7. Identification and multi-filter photometry of HII regions from nearby galaxies with J-PLUS

    NASA Astrophysics Data System (ADS)

    Logroño-García, R.; Vilella-Rojo, G.; López-Sanjuan, C.; Varela, J.; Muniesa, D.; Lamadrid, J. L.; Cenarro, A. J.; J-PLUS, T.

    2017-03-01

    The Javalambre Photometric Local Universe Survey (J-PLUS) has already started the data acquisition phase at the Observatorio Astrofísico de Javalambre (OAJ) in Teruel, Spain. Benefiting from the large field of view (2 deg^2) and the 12 filters set of the T80Cam at the T80/JAST telescope, we aim to study the properties of HII regions in nearby galaxies (z < 0.015). In this poster, we apply our procedures to the galaxy Messier 101. We have developed a fully automatized pipeline to identify and characterize the nearby universe HII regions. This pipeline: (1) Homogenizes the PSF in the 12 images of the different filters. (2) Estimates realistic photometric errors following Labbé et al. (2003) method. (3) Constructs a detection image showing the excess of Hα+[NII], following Vilella-Rojo et al. (2015) prescriptions. (4) Performs the photometry in the 12 J-PLUS bands using as reference the Hα+NII detection image. (5) Constructs the photo-spectra for each identified HII region. We demonstrate the capabilities of this method by comparing synthetic aperture photometry from SDSS spectra with the Hα flux measured with J-PLUS data. Such comparison can be found in the poster by Vilella-Rojo et al. Once the pipeline is implemented, we will generate a catalog of nearby HII regions at z<0.015 in the 8500deg^2 of J-PLUS. With this catalog, we will study the impact of environment in the 2D star formation properties of nearby galaxies, taking advantage of the unprecedented large contiguous area that J-PLUS will offer.

  8. Anatomy of Starbursts in Extragalactic Giant HII Regions: M51 Case Study

    NASA Astrophysics Data System (ADS)

    Evans, Jessica Marie; Chu, You-Hua

    2013-03-01

    Extragalactic giant HII regions (EGHRs) are sites of active, concentrated star formation, and thus provide excellent labs to analyze the starburst phenomenon. Although they have been known for a long time, ground-based observations cannot resolve the physical structures and stellar content of EGHRs. The high resolution and sensitivity of Hubble Space Telescope (HST) are ideal for detailed studies of EGHRs. We have searched the Hubble Legacy Archives (HLA) and found 17 nearby galaxies, within ˜15 Mpc, with Hα and continuum images; to determine the best methods for analyzing these data, we perform an in-depth analysis of the EGHRs in M51. M51 is a face-on spiral galaxy ˜8.4 Mpc away, with well-resolved multi-wavelength observations in the HLA. We sample the 25 most luminous HII regions in M51, many of which are bonafide EGHRs with an H-alpha luminosity > 1039 ergs s-1. We use the Hα image to study the distribution and physical structure of the gas in each HII region and determine its Hα luminosity and required ionizing flux. We use the continuum images to determine whether super stellar clusters (SSCs) are found in these HII regions, and use photometric measurements to determine the mass and age spread of the resolved stellar population. These are then compared with the interstellar structures. The results help us provide the groundwork for studying EGHRs in multiple galaxies and elucidate the starburst phenomenon by investigating questions such as: What role does environment play in the formation of EGHRs? How do EGHRs evolve? How does star formation proceed in an EGHR?

  9. Single Star HII Regions as Diagnostics for the Shapes of Stellar Atmosphere Model SEDs

    NASA Astrophysics Data System (ADS)

    Zastrow, Jordan; Oey, M. S.; Pellegrini, E. W.

    2013-06-01

    To evaluate the predictions of widely used stellar atmosphere models (CoStar, TLUSTY & WM-basic), we compare emission-line strengths from long slit observations of single-star HII regions to the predictions of CLOUDY photoionization simulations that use appropriate stellar atmosphere models for the ionizing stars. Str{o}mgren spheres such as these simplify many of the free parameters that complicate HII region modeling. The simulations generally reproduce the observed emission lines with ionization potentials below 35 eV, provided that we use a clumpy gas distribution. However, the predictions show large scatter from the observations for [Ne III] λ3869, which has the highest ionization potential of all detected lines (41 eV). Even simulations that use WM-basic, which have the best overall agreement with the observations, range from over- to under-predicting [Ne III] by 70% across the sample. We additionally compare the rate of ionizing photons, Q_0 derived from the Hα luminosity to that of the best fitting models. There is a systematic offset between the predicted Q_0 of different atmosphere models that corresponds to systematic variations in hardness of the SEDs. Our work demonstrates that single-star HII regions can provide fundamental diagnostic constraints on the shapes of stellar atmosphere models.

  10. Hα line profiles for a sample of supergiant HII regions. I. The main spectral component

    NASA Astrophysics Data System (ADS)

    Rozas, M.; Richer, M. G.; López, J. A.; Relaño, M.; Beckman, J. E.

    2006-08-01

    We present an analysis of the Hα emission line profiles of a sample of giant extragalactic HII regions, selected from among the brightest and most isolated in a group of spiral galaxies for which we have photometric and spectroscopic data: NGC 157, NGC 3631, NGC 6764, NGC 3344, NGC 4321, NGC 5364, NGC 5055, NGC 5985, NGC 7479. Our study confirms that the majority of the line profiles are composed of a bright, main component and two fainter, high velocity components that we denominate wings. Here, we analyze the kinematics of the principal components, finding a relation between the Hα luminosity, L_Hα, and the turbulent velocity dispersion, σ_nt. A linear fit to the relation between these quantities yields log L_Hα = (35.6 ± 0.4) + (2.87 ± 0.2)log σ_nt, in agreement with previous studies. We compute the mass of each HII region using both the virial theorem and the Hα luminosity, confirming that, though these estimates do not coincide exactly, they are comparable within the uncertainties and consequently that the HII regions in our sample are approximately virialized.

  11. PAH 8μm Emission as a Diagnostic of HII Region Optical Depth

    NASA Astrophysics Data System (ADS)

    Oey, M. S.; Lopez-Hernandez, J.; Kellar, J. A.; Pellegrini, E. W.; Gordon, Karl D.; Jameson, Katherine; Li, Aigen; Madden, Suzanne C.; Meixner, Margaret; Roman-Duval, Julia; Bot, Caroline; Rubio, Monica; Tielens, A. G. G. M.

    2017-01-01

    PAHs are easily destroyed by Lyman continuum radiation and so in optically thick Stromgren spheres, they tend to be found only on the periphery of HII regions, rather than in the central volume. We therefore expect that in HII regions that are optically thin to ionizing radiation, PAHs would be destroyed beyond the primary nebular structure. Using data from the Spitzer SAGE survey of the Magellanic Clouds, we test whether 8 μm emission can serve as a diagnostic of optical depth in HII regions. We find that 8 μm emission does provide valuable constraints in the Large Magellanic Cloud, where objects identified as optically thick by their atomic ionization structure have 6 times higher median 8 μm surface brightness than optically thin objects. However, in the Small Magellanic Cloud, this differentiation is not observed. This appears to be caused by extremely low PAH production in this low-metallicity environment, such that any differentiation between optically thick and thin objects is washed out by stochastic variations, likely driven by the interplay between dust production and UV destruction. Thus, PAH emission is sensitive to nebular optical depth only at higher metallicities.

  12. Drama of HII regions: Clustered and Triggered Star Formation

    NASA Astrophysics Data System (ADS)

    Li, Jin-Zeng; Yuan, Jinghua; Liu, Hong-Li; Wu, Yuefang; Huang, Ya-Fang

    2017-03-01

    In order to understand the star formation process under the influence of H ii regions, we have carried out extensive investigations to well selected star-forming regions which all have been profoundly affected by existing massive O type stars. On the basis of multi-wavelength data from mid-infrared to millimeter collected using Spitzer, Herschel, and ground based radio telescopes, the physical status of interstellar medium and star formation in these regions have been revealed. In a relatively large infrared dust bubble, active star formation is undergoing and the shell is still expanding. Signs of compressed gas and triggered star formation have been tentatively detected in a relatively small bubble. The dense cores in the Rosette Molecular Complex detected at 1.1 mm using SMA have been speculated to have a likely triggered origin according to their spatial distribution. Although some observational results have been obtained, more efforts are necessary to reach trustworthy conclusions.

  13. The HII regions and the velocity field of NGC 7331

    NASA Astrophysics Data System (ADS)

    Marcelin, M.; Petrosian, A. R.; Amram, P.; Boulesteix, J.

    1994-02-01

    The galaxy NGC 7331 has been observed with an IPCS through an H alpha filter for direct imagery and through a scanning Fabry-Perot interferometer at H aplha wavelength with the 2.60 m Byurakan telescope to study the main physical parameters of 47 H II regions, diameter and luminosity, as well as their velocities. The cumulative diameter distribution of H II regions is well represented by an exponential function with the parameters N0 = 272 and D0 = 95 pc. The H alpha luminosity function is described by a power law with index - 1.6. The H alpha velocity field of the galaxy is in good agreement with radio observations. Much less extended but offering a higher spatial resolution, it reveals non-circular motions, like the classical wiggles of the isovelocity lines when crossing a spiral arm, or the Z shape distortions of the isovelocity lines in the center possibly revealing an unseen bar.

  14. Hydrodynamic Instability of Ionization Fronts in HII Regions

    SciTech Connect

    Mizuta, A; Kane, J; Ryutov, D; Remington, B; Takabe, H; Pound, M

    2003-08-21

    The authors investigate hydrodynamic instability of accelerating ionization fronts with two dimensional hydrodynamic simulations. When recombination in the ionized region is turned off, Rayleigh-Taylor instability is effective. Perturbation grows up with classical Rayleigh-Taylor growth rate. In the case with recombination, the local difference of absorption profile works to smooth the surface. The perturbation does not grow and the amplitude follows a damped oscillations with time.

  15. Gravity Binding and Pressure Bounding of Hii regions and Molecular Clouds in Interacting Galaxies

    NASA Astrophysics Data System (ADS)

    Zaragoza-Cardiel, J.; Beckman, J.; Font, J.; Camps-Fariña, A.; Garcìa-Lorenzo, B.; Serrano-Borlaff, A.

    We have observed 3 pairs of interacting galaxies (the Antennae, Arp 236, and NGC 1614) using the Fabry-Perot interferometer GHαFaS (Galaxy Hα Fabry-Perot system) on the 4.2m William Herschel Telescope (WHT) at the Observatorio del Roque de los Muchachos, La Palma. We have extracted the physical properties (sizes, Hα luminosity and velocity dispersion) of Hii regions. We have combined also these observations with ALMA archival observations of these interacting galaxies, finding that there is a set of brighter and denser star forming regions. We have been able to compare these properties with those of two SMGs at redshift ~ 2.

  16. Formation of structures around HII regions: ionization feedback from massive stars

    NASA Astrophysics Data System (ADS)

    Tremblin, P.; Audit, E.; Minier, V.; Schmidt, W.; Schneider, N.

    2015-03-01

    We present a new model for the formation of dense clumps and pillars around HII regions based on shocks curvature at the interface between a HII region and a molecular cloud. UV radiation leads to the formation of an ionization front and of a shock ahead. The gas is compressed between them forming a dense shell at the interface. This shell may be curved due to initial interface or density modulation caused by the turbulence of the molecular cloud. Low curvature leads to instabilities in the shell that form dense clumps while sufficiently curved shells collapse on itself to form pillars. When turbulence is high compared to the ionized-gas pressure, bubbles of cold gas have sufficient kinetic energy to penetrate into the HII region and detach themselves from the parent cloud, forming cometary globules. Using computational simulations, we show that these new models are extremely efficient to form dense clumps and stable and growing elongated structures, pillars, in which star formation might occur (see Tremblin et al. 2012a). The inclusion of turbulence in the model shows its importance in the formation of cometary globules (see Tremblin et al. 2012b). Globally, the density enhancement in the simulations is of one or two orders of magnitude higher than the density enhancement of the classical ``collect and collapse`` scenario. The code used for the simulation is the HERACLES code, that comprises hydrodynamics with various equation of state, radiative transfer, gravity, cooling and heating. Our recent observations with Herschel (see Schneider et al. 2012a) and SOFIA (see Schneider et al. 2012b) and additional Spitzer data archives revealed many more of these structures in regions where OB stars have already formed such as the Rosette Nebula, Cygnus X, M16 and Vela, suggesting that the UV radiation from massive stars plays an important role in their formation. We present a first comparison between the simulations described above and recent observations of these regions.

  17. Elemental Abundances from Very Low Abundance HII Regions

    NASA Astrophysics Data System (ADS)

    Skillman, Evan D.; Terlevich, Roberto J.; Terlevich, Elena

    1992-12-01

    In 1987 we initiated a program to mitigate the deficiency of known low metallicity galaxies. Following our discoveries of very low abundance H II regions in nearby dwarf galaxies (Skillman et al. 1988, 1989a,b), we used the IDS on the INT to to collect spectra of dwarf galaxies in the Second Byurakan Survey (SBS) of UV excess galaxies. Our survey of over 40 SBS galaxies was completed in January 1990 and we have identified roughly one dozen very low metallicity H II galaxies. Now, with a significant sample of these galaxies, several observational programs are possible; foremost of these is the measurement of the primordial helium abundance (eg., Pagel et al. 1992). We report here on observations from March 1991 and 1992 using the ISIS spectrograph on the WHT to obtain very high quality spectra of 8 of these newly discovered metal-poor galaxies. The ISIS double spectrograph allows simultaneous observations of the blue (3600 - 5100 Angstroms) and red (6300 - 6800 Angstroms). Thus, He, N, O, Ne and S abundances can be derived with relatively small observational uncertainties. We compare our new observations with those in the literature. Our preliminary analysis indicates a slightly larger scatter in He/H at low O/H than had been seen previously. The small scatter may have been due simply to the paucity of observations at low metallicity. References: Pagel, B.E.J., Simonson, E.A., Terlevich, R.J., & Edmunds, M.G. 1992, MNRAS, 255, 325 Skillman, E.D., Kennicutt, R.C., & Hodge, P.W. 1989a, ApJ, 347, 875 Skillman, E.D., Melnick, J., Terlevich, R., & Moles, M. 1988, A&A, 196, 31 Skillman, E.D., Terlevich, R., & Melnick, J. 1989b, MNRAS, 240, 563

  18. Toward unveiling internal properties of Hii regions and their connections at the cosmic noon era

    NASA Astrophysics Data System (ADS)

    Shimakawa, Rhythm; Kodama, Tadayuki; Hayashi, Masao; Tadaki, Ken-Ichi; Suzuki, Tomoko L.; Koyama, Yusei; Tanaka, Ichi; Yamamoto, Moegi

    The redshift interval z = 2-3 is known as the cosmic noon that is the most active era of star formation across the Universe (Hopkins & Beacom 2006). In the past decade, many authors have investigated global properties of star-forming (SF) galaxies in this turbulent era, such as gas fractions and gaseous metallicities (e.g. Erb et al. 2006). With those achievements, we are going on to the next stage to understand more details i.e. those physical parameters in star-forming regions. Recent advent of near-infrared instruments typified by MOSFIRE on the Keck telescope, enable us with identifying the physical parameters of Hii regions in `typical' SF galaxies individually (Steidel et al. 2014). Recent highlights suggest higher electron densities, higher ionization parameters, and harder UV radiation fields may be common. In order to know how galaxy evolution physically correlates with the natures of their star-forming regions, we have explored relationships between the electron density (ne ) of ionized gas from the oxygen line ratio and other physical properties, based on the deep spectra of Hα emitters at z = 2.5 by the MOSFIRE. MOSFIRE for the first time provides ne of the galaxies at high-z with a high level of confidence. The result shows the specific star formation rate (sSFR) and the SFR surface density (ΣSFR) are correlated with ne (Shimakawa et al. 2015). The ne -ΣSFR relation could be linked to the star formation law in Hii regions if we assume that hydrogen in Hii regions is fully-ionized. Otherwise, more active star formation per unit area (higher ΣSFRs), may cause higher ionization states. However, we need some specific concerns that obtained physical parameters should depend on the scale dependence, since typical size of Hii region is only <100 pc despite that we study physical states of entire galaxies. Thus we obtain surface-brightness-weighted and ensemble averaged line fluxes for the entire galaxy or the part that falls into the slit width (a few kpc

  19. Infrared emission of young HII regions: a Herschel/Hi-GAL study

    NASA Astrophysics Data System (ADS)

    Cesaroni, R.; Pestalozzi, M.; Beltrán, M. T.; Hoare, M. G.; Molinari, S.; Olmi, L.; Smith, M. D.; Stringfellow, G. S.; Testi, L.; Thompson, M. A.

    2015-07-01

    Context. Investigating the relationship between radio and infrared emission of Hii regions may help shed light on the nature of the ionizing stars and the formation mechanism of early-type stars in general. Aims: We have taken advantage of recent unbiased surveys of the Galactic plane such as Herschel/Hi-GAL and VLA/CORNISH to study a bona fide sample of young Hii regions located in the Galactic longitude range 10°-65° by comparing the mid- and far-IR continuum emission to the radio free-free emission at 5 GHz. Methods: We have identified the Hi-GAL counterparts of 230 CORNISH Hii regions and reconstructed the spectral energy distributions of 204 of these by complementing the Hi-GAL fluxes with ancillary data at longer and shorter wavelengths. Using literature data, we obtained a kinematical distance estimate for 200 Hii regions with Hi-GAL counterparts and determined their luminosities by integrating the emission of the corresponding spectral energy distributions. We have also estimated the mass of the associated molecular clumps from the (sub)millimeter flux densities. Results: Our main finding is that for ~1/3 of the Hii regions the Lyman continuum luminosity appears to be greater than the value expected for a zero-age main-sequence star with the same bolometric luminosity. This result indicates that a considerable fraction of young, embedded early-type stars presents a "Lyman excess" possibly due to UV photons emitted from shocked material infalling onto the star itself and/or a circumstellar disk. Finally, by comparing the bolometric and Lyman continuum luminosities with the mass of the associated clump, we derive a star formation efficiency of 5%. Conclusions: The results obtained suggest that accretion may still be present during the early stages of the evolution of Hii regions, with important effects on the production of ionizing photons and thus on the circumstellar environment. More reliable numerical models describing the accretion process onto massive

  20. Toward unveiling internal properties of HII regions and their connections at the cosmic noon era

    NASA Astrophysics Data System (ADS)

    Shimakawa, Rhythm; Kodama, Tadayuki; Hayashi, Masao; Tadaki, Ken-ichi; Suzuki, Tomoko L.; Koyama, Yusei; Tanaka, Ichi; Yamamoto, Moegi

    2015-08-01

    The redshift interval z=2-3 is known as the cosmic noon that is the most active era of star formation across the Universe. In the past decade, many authors have investigated global properties of star-forming (SF) galaxies in this turbulent era, such as gas fractions and gaseous metallicities.With these achievements, we are going on to the next stage to understand the internal details of star formation at the cosmic noon era on the scale from entire galaxy into SF regions. Recent advent of near-infrared instruments typified by MOSFIRE on the Keck telescope, enable us with identifying the physical parameters of HII regions in ‘typical’ SF galaxies for the first time. Recent highlights suggest higher electron densities, higher ionization parameters, and harder UV radiation fields may be common.In this poster, based on the spectra of Hα selected SF galaxies at z=2.5 derived from MOSFIRE, we measure electron densities (ne) using the oxygen line ratio, and investigate the relationships between the electron density of ionized gas and other physical properties. As a result, we find that the specific star formation rate (sSFR) and the SFR surface density (ΣSFR) are correlated with the electron density. The ne-ΣSFR relation is likely to be linked to the star formation law in HII regions if we assume that hydrogen in HII regions is fully-ionized. However, we need some specific concerns that obtained physical parameters may depend on the scale dependence, since typical size of HII region is only <100 pc despite that we study physical states of entire galaxies. Thus we obtain surface-brightness-weighted and ensemble averaged line fluxes for the entire galaxy or the part that falls into the slit width.The thirty meter telescope (TMT) is a powerful instrument to resolve such a difficulty, since its spatial resolution reaches <100 pc on the physical scale at z~2 by AO assistance. This poster also presents what TMT can do for SF galaxies at z~2 with AO-assisted IFU

  1. VizieR Online Data Catalog: Galactic HII regions. I. Stellar distances (Foster+, 2015)

    NASA Astrophysics Data System (ADS)

    Foster, T.; Brunt, C. M.

    2016-04-01

    The cornerstone of our catalog of HII regions is the new systemic velocity measurements (with respect to the LSR), which come from high-resolution (1arcmin) λ21cm HI data and λ2.6mm 12CO (J=1-0) data. The HI data are entirely from the Canadian Galactic Plane Survey (CGPS; Taylor et al. 2003, cat. VI/128), whereas CO data are from either CGPS or the Exeter Five College Radio Astronomy Observatory (FCRAO) CO Galactic Plane Survey (described in Mottram & Brunt, 2010ASPC..438...98M; C. M. Brunt et al. 2013, in preparation), depending on longitude. Our catalog covers HII regions in the outer Galaxy only (R>R0) in the longitude range 90°{<=}l{<=}193° and mainly within a latitude of -3.5°{<=}b{<=}+5.5°. A high-latitude extension was also observed as part of the CGPS (99.85°{<=}l{<=}116.96°) up to b=+17.56°. The complete CGPS data set of 21cm line and continuum from 50.2°{<=}l{<=}193.3° and -3.55°{<=}b{<=}+5.55° are available at the Canadian Astronomy Data Centre (CADC; http://cadc.hia.nrc.ca/). 21cm HI line observations used herein were carried out with the seven-element interferometer and 26m radio telescopes at the Dominion Radio Astrophysical Observatory for the CGPS (Taylor et al. 2033, cat. VI/128). To trace molecular material in the second quadrant, we make use of the FCRAO Outer Galaxy Survey (OGS; Heyer et al., 1998ApJS..115..241H). We present our full catalog of 355 stars found in and around Galactic HII regions in Table1. Table2 in this paper gives the final heliocentric stellar distance to each of 103 nebulae in the outer Galaxy. (3 data files).

  2. VizieR Online Data Catalog: SN II in host HII regions (Anderson+, 2016)

    NASA Astrophysics Data System (ADS)

    Anderson, J. P.; Gutierrez, C. P.; Dessart, L.; Hamuy, M.; Galbany, L.; Morrell, N. I.; Stritzinger, M. D.; Phillips, M. M.; Folatelli, G.; Boffin, H. M. J.; de Jaeger, T.; Kuncarayakti, H.; Prieto, J. L.

    2016-07-01

    The data analysed in this publication comprise two distinct types of observations. The first is of SN II optical spectroscopy obtained during their photospheric phases, i.e. from discovery to at most ~100 days post explosion. These data are used to extract absorption line pEW measurements. The second data set is emission line spectral observations of host HII regions of SNe II. These are used to estimate SN II environment oxygen abundances, which can be used as metallicity proxies. In the course of this work we compare our observational results with the predictions from the spectral models of Dessart et al. (2014MNRAS.440.1856D). (2 data files).

  3. The HII Regions and OB Stars of M33 and NCG 6822.

    NASA Astrophysics Data System (ADS)

    Patel, Kanan

    1995-01-01

    We have used Hα and photometric data for two morphologically distinct Local Group galaxies, the spiral M33 and dwarf irregular NGC 6822, to study the distribution of the luminous blue O and B (OB) stars and HII regions in the galaxies as well as to determine whether individual regions of the galaxies are separately and/or collectively in a state of ionization balance. In the case of M33, we have concentrated on the inner 1 kpc region of the galaxy. Using the H alpha data, three distinct ionized gas environments (bright, halo and field) defined by the surface brightness of the Hα emission have been identified. We find that ~50% of the OB stars are located in the field, so that 1/2 of the lifetime of OB stars must be spent outside recognizable HII regions. We show that a possible origin for the large field OB population is that they were born in and subsequently percolated out of the ~10 ^3 giant molecular clouds with masses _sp{~}>10 ^3Modot predicted to exist within the inner kpc of the galaxy. Using UBV photometry and stellar ionization models, we predict Hα fluxes in the bright, halo and field regions. Our findings suggest that star formation rates obtained from luminosities must underestimate the true star formation rate within the inner region of M33. In the case of NGC 6822, four distinct components of the Hα emission (bright, halo, diffuse and field) differentiated by their surface brightnesses have been identified. We find that only 1/4 of the OB stars are found in the combined bright halo regions, suggesting that OB stars spend roughly 3/4 of their lifetimes outside "classical" HII regions. Molecular cloud lifetimes after forming OB stars could be as low as ~1 -3 times 10^6 yrs or 1/4 the typical main sequence lifetimes of OB stars if stars escape from bright HII regions by destroying their parent clouds. Additionally, the field population of OB stars cannot have originated in and percolated out of existing HII regions. Comparing the observed H

  4. The Skeleton in the Closet: Testing the Effect of HII Region Self-Enrichment Using Archival STIS Data

    NASA Astrophysics Data System (ADS)

    Werk, Jessica

    2013-10-01

    The idea that massive stars self-enrich their immediate surroundings on very short timescales has haunted emission-line spectroscopists for the last 27 years. Kunth and Sargent {1986} were the first to draw attention to this potentially significant flaw in the common practice of using HII regions to trace galaxy metallicity. In the years since, we have made little progress observationally in understanding the impact of the metal-rich winds of massive stars on the derived chemical abundances of their HII regions. Nonetheless, metallicity, as determined from emission line nebulae, remains one of the most important diagnostic tools of the extragalactic astronomer. We propose an archival study using STIS FUV spectra {E140M and E140H} of numerous massive stars in the LMC {11 total} and SMC {37 total} to determine the neutral gas-phase abundances along these lines-of-sight. We will then compare these results for the metal content of the neutral ISM to the ionized gas metallicities along the same lines-of-sight determined from ground-based optical spectroscopy of the local HII regions. This proposed study represents the first direct observational test of HII region self-enrichment on parsec-sized scales. As such, it will be a large step forward in finally confronting the skeleton in the astronomer's closet that is HII region self-enrichment.

  5. Massive Stellar Content of Stellar Clusters in M 31's Giant HII Region Pellet 550

    NASA Astrophysics Data System (ADS)

    Brandner, W.; Bik, A.; Rochau, B.; Gennaro, M.; Kudryavtseva, N.; Stolte, A.; Hussmann, B.; Zinnecker, H.

    We report on the first set of LBT/LUCIFER near infrared observations of Pellet 550, one of the most massive star-forming regions in the disk of M 31. Compared to the Milky Way, M 31 offers a complete census of star-forming regions and starburst clusters, all located at virtually the same distance. The regions under study have been selected to include the most luminous HII regions as well as still partially embedded star-forming regions recently revealed by Spitzer. For the first time we are able to establish the massive stellar content, identify young, massive clusters, and study the nature of still partially embedded luminous infrared sources. The M 31 study is a first application of our previous studies to establish the properties of Milky Way starburst clusters as templates for extragalactic massive star-forming regions.

  6. S7 : Probing the physics of Seyfert Galaxies through their ENLR & HII Regions

    NASA Astrophysics Data System (ADS)

    Dopita, Michael A.; Shastri, Prajval; Scharwächter, Julia; Kewley, Lisa J.; Davies, Rebecca; Sutherland, Ralph; Kharb, Preeti; Jose, Jessy; Bhatt, Harish; Ramya, S.; Hampton, Elise; Jin, Chichuan; Banfield, Julie; Zaw, Ingyin; Srivastava, Shweta; James, Bethan

    2015-02-01

    Here we present the first results from the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) which aims to investigate the physics of ~140 radio-detected southern active Galaxies with z<0.02 through Integral Field Spectroscopy using the Wide Field Spectrograph (WiFeS). This instrument provides data cubes of the central 38×25 arc sec. of the target galaxies in the waveband 340-710nm with the unusually high resolution of R=7000 in the red (530-710nm), and R=3000 in the blue (340-560nm). These data provide the morphology, kinematics and the excitation structure of the extended narrow-line region, probe relationships with the black hole characteristics and the host galaxy, measures host galaxy abundance gradients and the determination of nuclear abundances from the HII regions. From photoionisation modelling, we may determine the shape of the ionising spectrum of the AGN, discover whether AGN metallicities differ from nuclear abundances determined from HII regions, and probe grain destruction in the vicinity of the AGN. Here we present some preliminary results and modelling of both Seyfert galaxies observed as part of the survey.

  7. A single HII region model of the strong interstellar scattering towards Sgr A*

    NASA Astrophysics Data System (ADS)

    Sicheneder, Egid; Dexter, Jason

    2017-01-01

    Until recently, the strong interstellar scattering observed towards the Galactic center (GC) black hole, Sgr A*, was thought to come from dense gas within the GC region. The pulse broadening towards the transient magnetar SGR J1745-2900 near Sgr A* has shown that the source of the scattering is instead located much closer to Earth, possibly in a nearby spiral arm. We show that a single HII region along the line of sight, 1.5 - 4.8 kpc away from Earth with density ne of a few ˜eq 100 cm^{-3} and radius R ≃ 1.8 - 3.2 pc can explain the observed angular broadening of Sgr A*. Clouds closer to the GC overproduce the observed DM, providing an independent location constraint that agrees with that from the magnetar pulse broadening. Our model predicts that sources within ≲ 10 pc should show the same scattering origin as the magnetar and Sgr A*, while the nearest known pulsars with separations >20 pc should not. The radio spectrum of Sgr A* should show a cutoff from free-free absorption at 0.2 ≲ ν ≲ 1 GHz. For a magnetic field strength B ˜eq 15 - 70 {μ}G, the HII region could produce the rotation measure of the magnetar, the largest of any known pulsar, without requiring the gas near Sgr A* to be strongly magnetised.

  8. Properties of compact HII regions and their host clumps in the inner vs outer Galaxy - early results from SASSy

    NASA Astrophysics Data System (ADS)

    Djordjevic, Julie; Thompson, Mark; Urquhart, James S.

    2017-01-01

    We present a catalog of compact and ultracompact HII regions for all Galactocentric radii. Previous catalogs focus on the inner Galaxy (Rgal ≤ 8 kpc) but the recent SASSy 870 µm survey allows us to identify regions out to ~20 kpc. Early samples are also filled with false classifications leading to uncertainty when deriving star formation efficiencies in Galactic models. These objects have similar mid-IR colours to HII regions. Urquhart et al. (2013) found that they could use mid-IR, submm, and radio data to identify the genuine compact HII regions, avoiding confusion. They used this method on a small portion of the Galaxy (10 < l < 60), identifying 213 HII regions embedded in 170 clumps. We use ATLASGAL and SASSy, crossmatched with RMS, to sample the remaining galactic longitudes out to Rgal = 20 kpc. We derive the properties of the identified compact HII regions and their host clumps while addressing the implications for recent massive star formation in the outer Galaxy. Observations towards nearby galaxies are biased towards massive stars, affecting simulations and overestimating models for galactic evolution and star formation rates. The Milky Way provides the ideal template for studying factors affecting massive star formation rates and efficiencies at high resolution, thus fine-tuning those models. We find that there is no significant change in the rate of massive star formation in the outer vs inner Galaxy. Despite some peaks in known complexes and possible correlation with spiral arms, the outer Galaxy appears to produce massive stars as efficiently as the inner regions. However, many of the potential star forming SASSy clumps have no available radio counterpart to confirm the presence of an HII region or other star formation tracer. Follow-up observations will be required to verify this conclusion and are currently in progress.

  9. Chemical self-enrichment of HII regions by the Wolf-Rayet phase of an 85 M⊙ star

    NASA Astrophysics Data System (ADS)

    Kröger, D.; Hensler, G.; Freyer, T.

    2006-04-01

    It is clear from stellar evolution and from observations of WR stars that massive stars are releasing metal-enriched gas through their stellar winds in the Wolf-Rayet phase. Although Hii region spectra serve as diagnostics to determine the present-day chemical composition of the interstellar medium, it is far from being understood to what extent the Hii gas is already contaminated by chemically processed stellar wind. Therefore, we analyzed our models of radiative and wind bubbles of an isolated 85 M⊙ star with solar metallicity (Kröger et al. 2006, A&A, in preparation) with respect to the chemical enrichment of the circumstellar Hii region. Plausibly, the hot stellar wind bubble (SWB) is enriched with 14N during the WN phase and even much higher with 12C and 16O during the WC phase of the star. During the short period that the 85 M⊙ star spends in the WC stage enriched SWB material mixes with warm Hii gas of solar abundances and thus enhances the metallicity in the Hii region. However, at the end of the stellar lifetime the mass ratios of the traced elements N and O in the warm ionized gas are insignificantly higher than solar, whereas an enrichment of 22% above solar is found for C. Important issues from the presented study comprise a steeper radial gradient of C than O and a decreasing effect of self-enrichment for metal-poor galaxies.

  10. A New Scheme of Radiation Transfer in HII Regions including Transient Heating of Grains

    NASA Astrophysics Data System (ADS)

    Ghosh, S. K.; Verma, R. P.

    2000-06-01

    A new scheme of radiation transfer for understanding the infrared spectra of HII regions, has been developed. This scheme considers non-equilibrium processes (e.g. transient heating of the very small grains, VSG; and the polycyclic aromatic hydrocarbon, PAH) also, in addition to the equilibrium thermal emission from normal dust grains (BG). The spherically symmetric interstellar dust cloud is segmented into a large number of "onion skin" shells in order to implement the non-equilibrium processes. The scheme attempts to fit the observed SED originating from the dust component, by exploring the following parameters : (i) geometrical details of the dust cloud, (ii) PAH size and abundance, (iii) composition of normal grains (BG), (iv) radial distribution of all dust (BG, VSG & PAH). The scheme has been applied to a set of five compact HII regions (IRAS 18116-1646, 18162-2048, 19442+2427, 22308+5812 & 18434-0242) whose spectra are available with adequate spectral resolution. The best fit models and inferences about the parameters for these sources are presented.

  11. Spitzer observations of M33 and the hot star, HII region connection

    NASA Astrophysics Data System (ADS)

    Rubin, Robert H.; Simpson, Janet P.; Colgan, Sean W. J.; Dufour, Reginald J.; Brunner, Gregory; McNabb, Ian A.; Pauldrach, Adalbert W. A.; Erickson, Edwin F.; Haas, Michael R.; Citron, Robert I.

    2008-06-01

    We have observed emission lines of [SIV] 10.51, H(7-6) 12.37, [NeII] 12.81, [NeIII] 15.56 and [SIII] 18.71 μm in a number of extragalactic HII regions with the Spitzer Space Telescope. A previous paper presented our data and analysis for the substantially face-on spiral galaxy M83. Here we report our results for the Local Group spiral galaxy M33. The nebulae selected cover a wide range of galactocentric radii (RG). The observations were made with the Infrared Spectrograph with the short wavelength, high-resolution module. The above set of five lines is observed cospatially, thus permitting a reliable comparison of the fluxes. From the measured fluxes, we determine the ionic abundance ratios including Ne++/Ne+, S3+/S++, and S++/Ne+ and find that there is a correlation of increasingly higher ionization with larger RG. By sampling the dominant ionization states of Ne (Ne+, Ne++) and S (S++, S3+) for HII regions, we can estimate the Ne/H, S/H and Ne/S ratios. We find from linear least-squares fits that there is a decrease in metallicity with increasing RG: dlog(Ne/H)/dRG = -0.058 +/- 0.014 and dlog(S/H)/dRG = -0.052 +/- 0.021 dex kpc-1. There is no apparent variation in the Ne/S ratio with RG. Unlike our previous similar study of M83, where we conjectured that this ratio was an upper limit, for M33 the derived ratios are likely a robust indication of Ne/S. This occurs because the HII regions have lower metallicity and higher ionization than those in M83. Both Ne and S are primary elements produced in α-chain reactions, following C and O burning in stars, making their yields depend very little on the stellar metallicity. Thus, it is expected that the Ne/S ratio remains relatively constant throughout a galaxy. The median (average) Ne/S ratio derived for HII regions in M33 is 16.3 (16.9), just slightly higher than the Orion Nebula value of 14.3. The same methodology is applied to Spitzer observations recently published for three massive HII regions: NGC 3603 (Milky Way

  12. The chemical composition of planetary nebulae and HII regions in NGC 3109

    NASA Astrophysics Data System (ADS)

    Peña, M.; Stasińska, G.; Richer, M. G.

    2007-12-01

    Aims:We present deep spectrophotometry for a sample of 8 planetary nebulae (PNe) and 12 HII regions distributed throughout the dwarf irregular galaxy NGC 3109, in order to analyze the chemical composition of both types of nebulae. Methods: We describe the observations and data reduction, and present line intensities for the nebular emission lines detected. The physical conditions and the abundances of He, O, Ne, N, S and Ar are derived, using the classical T_e-based method. We confirm our previous identification of PNe and HII regions based on photometry, except for one object, which we argue is a compact HII region rather than a planetary nebula. Results: We find that the chemical composition of the interstellar medium in NGC 3109, as sampled by its HII regions, is remarkably uniform. The oxygen abundance is log O/H + 12 = 7.77 ± 0.07 in this galaxy, as compared to 8.05 ± 0.09 for the Small Magellanic Cloud (for which we rederived the metallicity in a homogeneous way). PNe show significantly higher oxygen abundances in NGC 3109: log O/H + 12 = 8.16 ± 0.19. Similarly to what has been suggested for some of the PNe in the Magellanic Clouds and other metal-poor galaxies, we argue that oxygen in the PNe in NGC 3109 is affected by dredge up in their progenitors. This could also be the case for neon, although the uncertainties for this element are bigger. Conclusions: From our analysis, we conclude that oxygen and neon are not always a safe indicator of the chemical composition of the interstellar medium at low metallicities. An alternative to the O and Ne enrichment in PNe is that the low metallicity in HII regions has been caused by dilution of the interstellar medium due to an interaction with a neighboring galaxy about a Gyr ago. The excitation patterns of the PNe in NGC 3109 are very different from the excitation patterns of PNe in other galaxies. This issue needs to be investigated further, as it implies that the evolution of PNe depends upon the properties of

  13. El medio interestelar en los alrededores de la region HII Sh2-183

    NASA Astrophysics Data System (ADS)

    Cichowolski, S.; Cappa, C. E.; Blanco, A.; Eppens, L.; Ertini, K.; Leiva, M. M.

    2017-10-01

    We present a multiwavelength study of the HII region Sh2-183, located at (,) = (123.3,+3.0) at a distance of 7.0 1.5 kpc from the Sun. Based on the radio continuum data we estimated the amount of ionized gas, the electronic density, and the number of ionizing photons needed to keep the region ionized, which is important since the star/s responsible of the region was/were not detected yet. On the other hand, based on IRAS data we have analyzed the dust temperature and distribution. The Hi line data allowed the detection of a shell-like structure surrounding the ionized gas and the CO data revealed the presence of 6 molecular clouds probably related to Sh2-183, which harbor several young stellar object candidates.

  14. [Ar III]/[O III] and [S III]/[O III]: well-behaved oxygen abundance indicators for HII regions and star forming galaxies

    NASA Astrophysics Data System (ADS)

    Stasińska, G.

    2006-08-01

    We propose two statistical methods to derive oxygen abundances in HII regions and star forming galaxies and calibrate them with a sample of several hundred giant HII regions in spiral and blue compact galaxies as well as of galaxies from the Sloan Digital Sky Survey. We show the advantages of our new abundance indicators over previous ones.

  15. Redetermination of the Helium Abundances in HII Regions in Blue Compact Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Holovatyi, V. V.; Melekh, B. Ya.

    2005-09-01

    The He/H abundances in HII regions in Blue Compact Dwarf Galaxies are redetermined using the new recombination coefficients of Benjamin et al. The electron number density n e in the He+ region, optical depth τ 3889 in the HeI λ3889 Å line, and coefficient of underlying stellar absorption a HeI are determined using the self-consistent method of Olive and Skillman. The primordial helium abundance and its enrichment are found using the helium abundances obtained in this paper and heavy-element abundances from our recent paper I: Y p = 0.244 ± 0.004 and dY/dZ = 8.8 ± 4.6.

  16. Extinction and PAH intensity variations across the HII region IRAS 12063-6259

    NASA Astrophysics Data System (ADS)

    Stock, D.; Peeters, E.; Tielens, X.; Otaguro, J.; Bik, A.

    The spatial variations in polycyclic aromatic hydrocarbon (PAH) band intensities are generally attributed to variations of the physical conditions in the environment hosting the emitting PAH molecules. However, in recent years, it has been suggested that such variations are caused mainly by extinction. To resolve this question, we have obtained near-infrared (NIR), mid-infrared (MIR) and radio observations of the compact HII region IRAS 12063-6259. We use these data to construct multiple independent extinction maps and to measure the main PAH feature intensities (6.2, 7.7, 8.6 and 11.2 µ m). Three extinction maps are derived: the first using the NIR hydrogen lines and case B recombination theory; the second combining the NIR data, radio data and case B recombination; and the third making use of the Spitzer/IRS MIR observations to measure the 9.8 µ m silicate absorption feature intensity using the Spoon method and PAHFIT. We conclude that different areas of IRAS 12063-6259 possess markedly different extinction properties, with some regions displaying both silicate absorption and corresponding NIR extinction, and other regions displaying NIR extinction and no corresponding silicate absorption. While such breakdowns of the relationship between the NIR extinction and the silicate absorption strength have been observed in molecular clouds, they have never been observed for HII regions. We then compare the PAH intensity variations in the Spitzer/IRS data after dereddening to those found in the original data. Generally it was found that the PAH band intensity variations persist even after dereddening, implying that extinction is not the main cause of the PAH band intensity variations.

  17. VizieR Online Data Catalog: Compact HII regions IR photometry (Phillips+, 2008)

    NASA Astrophysics Data System (ADS)

    Phillips, J. P.; Ramos-Larios, G.

    2009-07-01

    We have surveyed the entire GLIMPSE Atlas for likely compact HII regions (see Benjamin et al., 2003PASP..115..953B for the seminal article on this Atlas). Specifically, the GLIMPSE team has provided individual, and slightly overlapping images of the ATLAS for each IRAC band, and for ranges of {Delta}l=1.1{deg} in galactic longitude, and {Delta}b=0.8{deg} in galactic latitude, leading to a total of 1344 plates for the four bands combined [the high resolution (0.6arcsec/pix) data version is available at http://data.spitzer.caltech.edu/popular/glimpse/20070416enhancedv2/ 1.1x0.8_mosaics/. (2 data files).

  18. Extragalactic Ultracompact HII Regions: Probing the Birth Environments of Super Star Clusters

    NASA Astrophysics Data System (ADS)

    Johnson, K. E.

    2004-12-01

    In recent years, a number of extragalactic massive star clusters that are still deeply embedded in their birth material have been discovered. These objects represent the youngest stage of massive star cluster evolution yet observed, and the most massive and dense of these may be proto globular clusters. Their properties appear to be similar to those of ultracompact HII regions in the Galaxy, but scaled up in total mass and luminosity. In many cases, these clusters are only visible at mid-IR to radio wavelengths, and they have typically been detected as ``inverted'' spectrum radio sources. However, the set of existing observations is anemic, and our current physical model for these natal clusters in simplistic. This article will overview what we think we know about these objects based on existing observations and outline some of the most significant gaps in our current understanding.

  19. The Violent Interstellar Medium in the Giant HII Region 30 Doradus

    NASA Astrophysics Data System (ADS)

    Chu, Y.-H.; Grebel, E. K.; Bomans, D. J.; Smith, R. C.; Yang, H.

    1996-08-01

    The giant HII region 30 Doradus shows prominent filaments of ionized gas, bright diffuse X-ray emission, and violent internal gas motions. These features indicate the prevalence of interstellar shocks produced by fast stellar winds and supernova blasts. 30 Dor contains two clusters: the populous young cluster R 136 and the older cluster Hodge 301. The R 136 cluster, being only 3-4 million years old, should still have all its massive stars. Its most massive stars would be interacting with the ambient interstellar medium via copious stellar winds. The Hodge 301 cluster, being nearly 20 million years old, has lost its most massive stars. The remaining stars are not powerful sources of stellar winds, so the cluster has been interacting with the ambient medium mostly through occasional supernova blasts. The interstellar gas around these two clusters offers a unique opportunity for us to study a wind-dominated interaction and a supernova-dominated interaction in a giant HII region. We have obtained proprietary and archival HST WFPC2 images, ROSAT X-ray observations, and high-resolution echelle spectra of 30 Dor in the vicinity of R 136 as well as Hodge 301. These data are used to map the distribution of high velocity gas and to determine the origin of interstellar shocks. We show that the kinematic signatures of wind-dominated shocks and supernova remnant shocks are distinctly different. The most violent motion in 30 Dor is associated with the older cluster Hodge 301. Clearly, star formation in 30 Dor is not coeval; while the younger cluster is responsible for the ionization of the interstellar gas, the older cluster is responsible for the violent interstellar motion. If 30 Dor represents a miniature but typical starburst situation, these results must be taken into account when studying distant, unresolved starburst phenomena.

  20. Spectral line survey of the ultracompact HII region Monoceros R2

    NASA Astrophysics Data System (ADS)

    Ginard, D.; González-García, M.; Fuente, A.; Cernicharo, J.; Alonso-Albi, T.; Pilleri, P.; Gerin, M.; García-Burillo, S.; Ossenkopf, V.; Rizzo, J. R.; Kramer, C.; Goicoechea, J. R.; Pety, J.; Berné, O.; Joblin, C.

    2012-07-01

    Context. Ultracompact (UC) Hii regions constitute one of the earliest phases in the formation of a massive star and are characterized by extreme physical conditions (G0 > 105 Habing field and n > 106 cm-3). The UC Hii Mon R2 is the closest example and an excellent target to study the chemistry in these complex regions. Aims: Our goal is to investigate the chemistry of the molecular gas around UC Hii Mon R2 and the variations caused by the different local physical conditions. Methods: We carried out 3 mm and 1 mm spectral surveys using the IRAM 30-m telescope towards three positions that represent different physical environments in Mon R2: (i) the ionization front (IF) at (0″, 0″), and two peaks in the molecular cloud; (ii) molecular Peak 1 (hereafter MP1) at the offset (+15″, -15″); and (iii) molecular Peak 2 (hereafter MP2) at the farther offset (0″, 40″). In addition, we carried out extensive modeling to explain the chemical differences between the three observed regions. Results: We detected more than 30 different species (including isotopologues and deuterated compounds). In particular, we detected SO+ and C4H confirming that ultraviolet (UV) radiation plays an important role in the molecular chemistry of this region. In agreement with this interpretation, we detected the typical photo-dissociation region (PDR) molecules CN, HCN, HCO, C2H, and c-C3H2. There are chemical differences between the observed positions. While the IF and the MP1 have a chemistry similar to that found in high UV field and dense PDRs such as the Orion Bar, the MP2 is similar to lower UV/density PDRs such as the Horsehead nebula. Our chemical modeling supports this interpretation. In addition to the PDR-like species, we detected complex molecules such as CH3CN, H2CO, HC3N, CH3OH, and CH3C2H that are not usually found in PDRs. The sulfur compounds CS, HCS+, C2S, H2CS, SO, and SO2 and the deuterated species DCN and C2D were also identified. The origin of these complex species

  1. Predicted emission lines from giant HII regions ionized by aging star clusters.

    NASA Astrophysics Data System (ADS)

    Garcia-Vargas, M. L.; Bressan, A.; Diaz, A. I.

    1995-07-01

    We have computed theoretical models of the emission line spectra of giant extragalactic HII regions (GEHR) in which a single star cluster is assumed to be responsible for the ionization. Ionizing clusters, of different masses and metallicities, were constructed assuming that they formed in a single burst and with a Salpeter Initial Mass Function. Their evolution was then followed in detail up to an age of 5.4Myr after which they lack the high energy photons needed to keep the regions ionized. The integrated spectral energy distribution of every cluster has been computed for a set of discrete ages representative of relevant phases of their evolution and have been processed by the photoionization code CLOUDY, in order to obtain the corresponding emission line spectra of the ionized gas at optical and infrared wavelengths. A wide range of initial compositions, spanning from about 1/20 (Z=0.001) to 2.5 solar (Z=0.05), and total masses, between about 1-6x10^4^Msun_ has been considered. Gas and stars are assumed to have the same metallicity and this has been taken into account both in the stellar evolution and atmosphere models and in the nebular gas producing a consistent set of models. In this paper we present the synthetic emission line spectra of the ionized regions which are discussed in detail in Garcia-Vargas et al. (1995).

  2. VizieR Online Data Catalog: VLA observations of ultracompact HII regions (Molinari+ 1998)

    NASA Astrophysics Data System (ADS)

    Molinari, S.; Brand, J.; Cesaroni, R.; Palla, F.; Palumbo, G. G. C.

    1998-05-01

    We have used the Very Large Array (VLA) to search for radio continuum emission towards a sample of 67 IRAS sources selected from a previous study. All observed sources are associated with high density molecular gas, exhibit an infrared spectral energy distribution characteristic of very cold young stellar objects and many of them are associated with H2O masers. The observed sample is divided into two groups of sources: High, with IRAS spectral energy distributions resembling those of ultracompact HII regions, and Low, for which previously collected evidence suggests that they may contain a higher fraction of protostellar objects than the High group; such objects might not have started hydrogen burning yet. Radio continuum emission was detected towards 37 sources (55%), although only in 22 cases an association with the IRAS source is established. Of the latter, 9 (24%) objects belong to the Low type and 13 (43%) to the High type. Thus, we find that 76% of Low and 57% of High sources are not associated with a radio counterpart. Because the majority of the sources have luminosities above ~104L⊙, corresponding to central stars of spectral type between B2 and O7, the lack of radio emission is interpreted as being due to the action of accreting matter that chokes off the expansion of the ionised gas. We show that this require s only moderate mass accretion rates, below ~10-4M⊙/yr. Alternatively, dust absorption can also effectively absorb UV photons and the gas column density implied by our observations indicates values in excess of 1022cm-2. The physical properties of IRAS sources with associated radio counterpa rt derived from the present observations do not distinguish between High and Low sources. These sources are likely to be ZAMS stars with variable amounts of dust within the ionised region which acts as UV field absorber. The large majority of detected sources (75%) have spherical or unresolved morphology, while 15% are irregular or multiply peaked and only

  3. Triggered massive star formation associated with the bubble Hii region Sh2-39 (N5)

    NASA Astrophysics Data System (ADS)

    Duronea, N. U.; Cappa, C. E.; Bronfman, L.; Borissova, J.; Gromadzki, M.; Kuhn, M. A.

    2017-09-01

    Aims: We perform a multiwavelength analysis of the bubble Hii region Sh2-39 (N5) and its environs with the aim of studying the physical properties of Galactic IR bubbles and exploring their impact in triggering massive star formation. Methods: To analyze the molecular gas, we used CO(3-2) and HCO+(4-3) line data obtained with the on-the-fly technique from the ASTE telescope. To study the distribution and physical characteristics of the dust, we made use of archival data from ATLASGAL, Herschel, and MSX, while the ionized gas was studied making use of an NVSS image. We used public WISE, Spitzer, and MSX point source catalogs to search for infrared candidate young stellar objects (YSOs) in the region. To investigate the stellar cluster [BDS2003]6 we used IR spectroscopic data obtained with the ARCoIRIS spectrograph, mounted on Blanco 4 m Telescope at CTIO, and new available IR Ks band observations from the VVVeXtended ESO Public Survey (VVVX). Results: The new ASTE observations allowed the molecular gas component in the velocity range from 30 km s-1 to 46 km s-1, associated with Sh2-39, to be studied in detail. The morphology of the molecular gas suggests that the ionized gas is expanding against its parental cloud. We identified four molecular clumps, which were likely formed by the expansion of the ionization front, and determined some of their physical and dynamical properties. Clumps with HCO+ and 870 μm counterparts show evidence of gravitational collapse. We identified several candidate YSOs across the molecular component. Their spatial distribution and the fragmentation time derived for the collected layers of the molecular gas suggest that massive star formation might have been triggered by the expansion of the nebula via the collect and collapse mechanism. The spectroscopical distance obtained for the stellar cluster [BDS2003]6, placed over one of the collapsing clumps in the border of the Hii region, reveals that this cluster is physically associated with

  4. Rotation curves and metallicity gradients from HII regions in spiral galaxies

    NASA Astrophysics Data System (ADS)

    Márquez, I.; Masegosa, J.; Moles, M.; Varela, J.; Bettoni, D.; Galletta, G.

    2002-10-01

    In this paper we study long slit spectra in the region of Hα emission line of a sample of 111 spiral galaxies with recognizable and well defined spiral morphology and with a well determined environmental status, ranging from isolation to non-disruptive interaction with satellites or companions. The form and properties of the rotation curves are considered as a function of the isolation degree, morphological type and luminosity. The line ratios are used to estimate the metallicity of all the detected HII regions, thus producing a composite metallicity profile for different types of spirals. We have found that isolated galaxies tend to be of later types and lower luminosity than the interacting galaxies. The outer parts of the rotation curves of isolated galaxies tend to be flatter than in interacting galaxies, but they show similar relations between global parameters. The scatter of the Tully-Fisher relation defined by isolated galaxies is significantly lower than that of interacting galaxies. The [NII]/Hα ratios, used as a metallicity indicator, show a clear trend between Z and morphological type, t, with earlier spirals showing higher ratios; this trend is tighter when instead of t the gradient of the inner rotation curve, G, is used; no trend is found with the change in interaction status. The Z-gradient of the disks depends on the type, being almost flat for early spirals, and increasing for later types. The [NII]/Hα ratios measured for disk HII regions of interacting galaxies are higher than for normal/isolated objects, even if all the galaxy families present similar distributions of Hα Equivalent Width. Tables 3 and 4 and Figs. 6, 7 and 21 are only available in electronic form at http://www.edpsciences.org. Table 5 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/393/389 Based on data obtained Asiago/Ekar Observatory. Also based on observations made

  5. Formation of Pillars at the Boundaries between HII Regions and Molecular Clouds

    SciTech Connect

    Mizuta, A; Kane, J O; Pound, M W; Remington, B A; Ryutov, D D; Takabe, H

    2006-04-20

    We investigate numerically the hydrodynamic instability of an ionization front (IF) accelerating into a molecular cloud, with imposed initial perturbations of different amplitudes. When the initial amplitude is small, the imposed perturbation is completely stabilized and does not grow. When the initial perturbation amplitude is large enough, roughly the ratio of the initial amplitude to wavelength is greater than 0.02, portions of the IF temporarily separate from the molecular cloud surface, locally decreasing the ablation pressure. This causes the appearance of a large, warm HI region and triggers nonlinear dynamics of the IF. The local difference of the ablation pressure and acceleration enhances the appearance and growth of a multimode perturbation. The stabilization usually seen at the IF in the linear regimes does not work due to the mismatch of the modes of the perturbations at the cloud surface and in density in HII region above the cloud surface. Molecular pillars are observed in the late stages of the large amplitude perturbation case. The velocity gradient in the pillars is in reasonably good agreement with that observed in the Eagle Nebula. The initial perturbation is imposed in three different ways: in density, in incident photon number flux, and in the surface shape. All cases show both stabilization for a small initial perturbation and large growth of the second harmonic by increasing amplitude of the initial perturbation above a critical value.

  6. LkHa101, an extreme emission line star with a disk and illuminating an HII region

    NASA Astrophysics Data System (ADS)

    Sandell, Goran H. L.; Vacca, William D.; Corder, Stuartt

    2016-01-01

    We present new results on LkHa101 based on the mid-infrared imaging with FORCAST on SOFIA, CARMA 3 mm imaging, IRTF SpeX medium resolution spectra from 0.8 - 5 micron, and Herschel PACS archive data. These observations, combined with published VLA data eveal that LkHa 101 is still surrounded by a face-on photo-evaporating accretion disk and is illuminating an HII region. The accretion disk is hot T > 1000 K) and mostly ionized. The FORCAST, PACS and CARMA CO(1-0) and 13CO(1-0) images show a strong interaction between the dense molecular cloud north of LkHa101 and the expanding HII region, but no interaction with the cold foreground cloud providing most of the extinction toward the star.

  7. Spectroscopy of Extragalactic HII Regions and Development of a Multi-Fiber Spectrograph for a Small Telescope.

    NASA Astrophysics Data System (ADS)

    Wang, Jianguo

    1992-01-01

    Nous avons obtenu des spectres optiques de la region HII geante CM 67 situee pres du centre de la galaxie NGC 4631. Des comparaisons ont ete faites avec des observations en continu radio, en emission CO et en HI. Nous suggerons que CM 67 represente l'extremite "proche" d'une barre mesurant quelques kpc. Nous presentons ensuite la spectrophotometrie optique detaillee pour deux positions de fente de la region HII geante NGC 604 situee dans la galaxie M33. Le comportement spatial des rapports de raies le long de la fente a ete etudie. Une region montrant un remarquable spectre a composantes multiples a ete mise en evidence et correspond a une etoile de type Of/WN. Enfin, nous presentons un spectrographe multi -objets a fibres optiques qui a ete developpe pour le telescope de 1.6 m de l'Observatoire du mont Megantic. Des observations de regions HII dans M31 ont ete menees a l'aide de ce nouveau MOS. Un nouveau type de MOS offrant la possibilite d'une spectroscopic multi-objets bidimensionnelle est aussi presente.

  8. Radiation-MHD models of elephant trunks and globules in HII regions

    NASA Astrophysics Data System (ADS)

    Mackey, Jonathan; Lim, Andrew J.

    2011-01-01

    We study the formation and evolution of pillars of dense gas, known as elephant trunks, at the boundaries of HII regions, formed by shadowing of ionising radiation by dense clumps. The effects of magnetic fields on this process are investigated using 3D radiation-magnetohydrodynamics simulations. For a simulation in which an initially uniform magnetic field of strength \\vert B\\vert≃50 μG is oriented perpendicular to the radiation propagation direction, the field is swept into alignment with the pillar during its dynamical evolution, in agreement with observations of the ``Pillars of Creation'' in M16, and of some cometary globules. This effect is significantly enhanced when the simulation is re-run with a weaker field of ≃18 μG. A stronger field with \\vert B\\vert≃ 160 μG is sufficient to prevent this evolution completely, also significantly affecting the photoionisation process. Using a larger simulation domain it is seen that the pillar formation models studied in Mackey & Lim (2010) ultimately evolve to cometary structures in the absence of dense gas further from the star.

  9. Dynamical models for the formation of elephant trunks in HII regions

    NASA Astrophysics Data System (ADS)

    Mackey, Jonathan; Lim, Andrew J.

    2010-04-01

    The formation of pillars of dense gas at the boundaries of HII regions is investigated with hydrodynamical numerical simulations including ionizing radiation from a point source. We show that shadowing of ionizing radiation by an inhomogeneous density field is capable of forming so-called elephant trunks (pillars of dense gas as in e.g. M16) without the assistance of self-gravity or of ionization front and cooling instabilities. A large simulation of a density field containing randomly generated clumps of gas is shown to naturally generate elephant trunks with certain clump configurations. These configurations are simulated in isolation and analysed in detail to show the formation mechanism and determine possible observational signatures. Pillars formed by the shadowing mechanism are shown to have rather different velocity profiles depending on the initial gas configuration, but asymmetries mean that the profiles also vary significantly with perspective, limiting their ability to discriminate between formation scenarios. Neutral and molecular gas cooling are shown to have a strong effect on these results.

  10. Ionizing Sources of Extragalactic HII Regions: Tight Clusters vs. Distributed OB Associations

    NASA Astrophysics Data System (ADS)

    Evans, Jessica Marie; Chu, Y.

    2011-01-01

    Extragalactic giant HII regions (EGHRs) are sites of active, concentrated star formation, providing ideal labs to analyze starburst phenomenon. The most interesting starburst issue is whether a tight cluster forms and later becomes a globular cluster or distributed OB associations form and later disperse. The two nearest EGHRs serve as standards for each; 30 Dor in the Large Magellanic Cloud hosts a dominant cluster and NGC 604 in M33 hosts multiple OB associations. To investigate the mode of star formation in EGHRs, we have searched the Hubble Legacy Archives (HLA) and identified a sample of >50 EGHRs in galaxies closer than 15 Mpc, limiting our selection by an H-alpha luminosity threshold of 1.5 x 1040 ergs s-1. Binned images of 30 Dor and NGC 604 in continuum bands are used to simulate clusters and distributed OB associations at distances of the EGHRs in our HLA sample. We have analyzed the continuum images of the EGHRs and compared them with the simulated images of 30 Dor and NGC 604 in order to assess whether the ionizing source is dominated by a tight cluster or distributed OB associations. We have also correlated the modes of star formation in EGHRs with the types of their host galaxies and their location within them. Implications of our results on starbursts and formation of EGHRs will be discussed.

  11. Objects earlier than precursors of UC HII regions: Inflow-signpost for a common way of star formation

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Zhu, M.; Xu, D.; Wei, Y.; Zhu, L.

    Searching for objects in the earliest phases of star formation, e.g sources at the beginning of a gravitational collapse, are essential to our understanding of massive star formation. Today a number of precursors of ultra compact HII regions (PUCHs) have been found. Embedded in dense gas and dust, these PUCHs have a high bolometric luminosity but little or no 6 cm radio continuum emission (Molinari, et al. 2000; Beuther, et al. 2002). Evidence for Collapse was found in ultra compact (UC) HII regions and 12 water maser sources (Zhang, et al. 1998; Wu & Evans II 2003). This paper presents the identification of massive cores with no detectable infrared and radio sources. These kinds of cores usually have strong sub-mm emission. A special case is the SCUBA core JCMT 18354-0649S which has both infall and outflow motions as indicated by the profiles of high excitation molecular lines. This core is at a stage earlier than PUCHs. Blue profiles are also found in UC HII region, which indicates that material is still infalling in this phase. Our observations suggest that infall exists in different evolutionary stages for high mass star formation, similar to the low mass cases.

  12. ISO Mid-Infrared Observations of Giant HII Regions in M33

    NASA Technical Reports Server (NTRS)

    Skelton, B. P.; Waller, W. H.; Hodge, P. W.; Boulanger, F.; Cornett, R. H.; Fanelli, M. N.; Lequeux, J.; Stecher, T. P.; Viallefond, F.; Hui, Y.

    1999-01-01

    We present Infrared Space Observatory Camera (ISOCAM) Circular Variable Filter scans of three giant HII regions in M33. IC 133, NGC 595, and CC 93 span a wide range of metallicity, luminosity, nebular excitation, and infrared excess; three other emission regions (CC 43, CC 99, and a region to the northeast of the core of NGC 595) are luminous enough in the mid-infrared to be detected in the observed fields. ISOCAM CVF observations provide spatially resolved observations (5'') of 151 wavelengths between 5.1 and 16.5 microns with a spectral resolution R = 35 to 50. We observe atomic emission lines ([Ne II], [Ne III], and [S IV]), several "unidentified infrared bands" (UIBs; 6.2, 7.7, 8.6, 11.3, 12.0, and 12.7 microns), and in some cases a continuum which rises steeply at longer wavelengths. We conclude that the spectra of these three GHRs are well explained by combinations of ionized gas, PAHs, and very small grains in various proportions and with different spatial distributions. Comparisons between observed ratios of the various UIBs with model ratios indicate that the PAHs in all three of the GHRs are dehydrogenated and that the small PAHs have been destroyed in IC 133 but have survived in NGC 595 and CC 93. The [Ne III]/[Ne II] ratios observed in IC 133 and NGC 595 are consistent with their ages of 5 and 4.5 Myr, respectively; the deduced ionization parameter is higher in IC 133, consistent with its more compact region of emission.

  13. ISO Mid-Infrared Observations of Giant HII Regions in M33

    NASA Technical Reports Server (NTRS)

    Skelton, B. P.; Waller, W. H.; Hodge, P. W.; Boulanger, F.; Cornett, R. H.; Fanelli, M. N.; Lequeux, J.; Stecher, T. P.; Viallefond, F.; Hui, Y.

    1999-01-01

    We present Infrared Space Observatory Camera (ISOCAM) Circular Variable Filter scans of three giant HII regions in M33. IC 133, NGC 595, and CC 93 span a wide range of metallicity, luminosity, nebular excitation, and infrared excess; three other emission regions (CC 43, CC 99, and a region to the northeast of the core of NGC 595) are luminous enough in the mid-infrared to be detected in the observed fields. ISOCAM CVF observations provide spatially resolved observations (5'') of 151 wavelengths between 5.1 and 16.5 microns with a spectral resolution R = 35 to 50. We observe atomic emission lines ([Ne II], [Ne III], and [S IV]), several "unidentified infrared bands" (UIBs; 6.2, 7.7, 8.6, 11.3, 12.0, and 12.7 microns), and in some cases a continuum which rises steeply at longer wavelengths. We conclude that the spectra of these three GHRs are well explained by combinations of ionized gas, PAHs, and very small grains in various proportions and with different spatial distributions. Comparisons between observed ratios of the various UIBs with model ratios indicate that the PAHs in all three of the GHRs are dehydrogenated and that the small PAHs have been destroyed in IC 133 but have survived in NGC 595 and CC 93. The [Ne III]/[Ne II] ratios observed in IC 133 and NGC 595 are consistent with their ages of 5 and 4.5 Myr, respectively; the deduced ionization parameter is higher in IC 133, consistent with its more compact region of emission.

  14. Massive Star Formation in NGC4038/4039: HII Regions and Supernova Remnants in "The Antennae"

    NASA Technical Reports Server (NTRS)

    Neff, S. G.; Ulvestad, J. S.; Fisher, Richard (Technical Monitor)

    2000-01-01

    The nearest merger, NGC4038/4039 ("The Antennae, Arp244), is undergoing a starburst apparently triggered and driven by the ongoing interaction. The system provides an excellent laboratory to study star formation processes because well-studied and nearby (21 Mpc assumed here). Models of the interaction suggest that the interaction's first periapse occurred 200 Myr ago, and that final coalescence will occur in another 100 Myr. Blue and H alpha images show a continuous loop of bright knots around the NGC4038 (northern) nucleus, continuing down through the NGC4039 (southern) nucleus. Recent HST V and I images resolve the star-forming knots into several thousand blue compact clusters, with ages 5Myr for the youngest clusters. Far Ultraviolet (lambda 1500A) observations directly detect O and B stars in regions of low extinction; the total mass of young stars so observed is approximately 8 x 10 (exp 5) solar mass. FIR observations imply a star formation rate of approximately 5 M (sub 0) dot yr (sup -1) or greater. We used the VLA at 6 and 4 cm to obtain high resolution radio images of the star-formation regions in NGC4038/4038. We used high resolution imaging to identify compact radio emitting regions and spectral indices of the compact regions to differentiate between thermal sources such as HII regions (flat spectra) and supernova, remnants (steep spectra). We found that compact radio sources produce approximately 12% and/sim 25 strongest radio emission occurs between the galaxies, at an optically unremarkable location near but not coincident with an extremely red cluster. The radio peak is at a location of intense star formation (as detected in the mid-IR, reference?) and of dense molecular gas. We identify 115 individual compact 6cm radio sources and 63 individual 4 cm sources in the system, to a limiting luminosity of approximately 2 x 10 (exp 1) 8 W Hz (sup -1) (or /sim4x the luminosity of Cas A). Of the strongest sources, for which the h flux densities are large

  15. Kinematic Study of Ionized and Molecular Gases in Ultracompact HII Region in Monoceros R2

    NASA Astrophysics Data System (ADS)

    Kim, Hwihyun; Lacy, John H.; Jaffe, Daniel Thomas

    2017-06-01

    Monoceros R2 (Mon R2) is an UltraCompact HII region (UCHII) surrounded by several PhotoDissociation Regions (PDRs). It is an excellent example to investigate the chemistry and physics of early stage of massive star formation due to its proximity (830pc) and brightness. Previous studies suggest that the wind from the star holds the ionized gas up against the dense molecular core and the higher pressure at the head drives the ionized gas along the shell. In order for the model to work, there should be evidence for dense molecular gas along the shell walls, irradiated by the UCHII region and perhaps entrained into the flow along the walls.We obtained the Immersion Grating INfrared Spectrograph (IGRINS) spectra of Mon R2 to study the kinematic patterns in the areas where ionized and molecular gases interact. The position-velocity maps from the high resolution (R~45,000) H- and K-band (1.4-2.5μm) IGRINS spectra demonstrate that the ionized gases (Brackett and Pfund series, He and Fe emission lines; Δv ≈ 40km/s) flow along the walls of the surrounding clouds. This is consistent with the model by Zhu et al. (2008). In the PV maps of the H2 emission lines there is no obvious motion (Δv ≈ 10km/s) of the molecular hydrogen right at the ionization boundary. This implies that the molecular gas is not taking part in the flow as the ionized gas is moving along the cavity walls.This work used the Immersion Grating Infrared Spectrograph (IGRINS) that was developed under a collaboration between the University of Texas at Austin and the Korea Astronomy and Space Science Institute (KASI) with the financial support of the US National Science Foundation (NSF; grant AST-1229522), of the University of Texas at Austin, and of the Korean GMTProject of KASI.

  16. Dusty Cradles in a Turbulent Nursery: The Sgr A East HII Region Complex at the Galactic Center

    NASA Astrophysics Data System (ADS)

    Lau, Ryan M.; Herter, Terry; Morris, Mark; Adams, Joseph

    2015-08-01

    We present high spatial resolution (FWHM ~ 3.2’’ - 3.8’’) imaging performed by the FORCAST instrument on SOFIA at 19, 25, 31, and 37 μm of the compact HII region complex G-0.02-0.07, the site of the most recent confirmed star formation within ~10 pc of the Galactic center. G-0.02-0.07 contains three compact HII regions (A, B, and C) and one ultra-compact HII region (D). Using this multiband imaging along with DustEM, we constrain the gas-to-dust mass ratios (~45 - 65) and the relative mass abundances of large grains, very small grains, and PAHs in the emitting dust from each region. Combining the inferred stellar luminosities, the expected and observed 1.90 μm fluxes and the observed dust thermal structure, the previously suggested heating sources for regions A, B, and C are confirmed. However, for region D, the observed fluxes at 1.87 and 1.90 μm of the previously proposed ionizing star are a factor of ~40 times too bright to be the heating source. We find that the location of the Region A heating source and the morphology of surrounding dust emission is consistent with that of a bow-shock, which suggests the heating source may have been ejected from its initial birth site rather than forming in-situ. In the ejection scenario for the Region A heating source, we estimate a lower limit on its age of ~104 yrs based on the size of the bow-shock.

  17. Physical Conditions of the Small Magellanic Cloud HII Region NGC 456 and the Underestimated Heavy Element Abundances of the Universe

    NASA Astrophysics Data System (ADS)

    Pena-Guerrero, Maria Angeles; Peimbert, A.

    2011-01-01

    We study the O/H abundance determinations in HII regions in the presence of temperature inhomogeneities (as proposed by Peimbert in 1967), t2. The first object of our study is NGC 456, which the second brightest HII region of the Small Magellanic Clouds (SMC); we find it has an abundance 1.75 times higher than previously determined. Traditionally it is assumed that these objects have the same temperature throughout the whole volume; this temperature is then used to calculate abundances. Our determination was done using Collisionally Excited Lines (CEL) and the t2 obtained from HeI lines; it is consistent with abundances determined with Recombination Lines (RL). The most well known strong-line ratio or metallicity indicator used to determine the O/H ratio is O23= ([OII]3727Å + [OIII]4959,5007Å) / Hβ introduced by Pagel et al. (1979). The log(O23) vs. 12+log(O/H) diagram constitutes an important tool in the study of objects with low intrinsecal brightness or high redshift. To account for the presence of thermal inhomogeneities, the upper branch of the O23-O/H diagram can be recalibrated using RLs whereas in the lower branch of the diagram RLs cannot be used due to their faintness. For low metallicity objects the formalism of t2 is applied to CELs to determine abundances and recalibrate the O23-O/H diagram. We find that the point corresponding to NGC 456 in the diagram shifts up by 0.24 dex in the 12+log(O/H) axis. This is consistent with preliminary results for the next 3 objects of our sample and with the behavior of other HII regions from the literature were t2 has been measured. The systematic shift in the curve of the O23-O/H diagram implies that abundances in the Universe need to be corrected by a factor of approximately 2.

  18. The first CO+ image: I. Probing the HI/H2 layer around the ultracompact HII region Mon R2

    PubMed Central

    Treviño-Morales, S. P.; Fuente, A.; Sánchez-Monge, Á.; Pilleri, P.; Goicoechea, J. R.; Ossenkopf-Okada, V.; Roueff, E.; Rizzo, J. R.; Gerin, M.; Berné, O.; Cernicharo, J.; Gónzalez-García, M.; Kramer, C.; García-Burillo, S.; Pety, J.

    2016-01-01

    The CO+ reactive ion is thought to be a tracer of the boundary between a HII region and the hot molecular gas. In this study, we present the spatial distribution of the CO+ rotational emission toward the Mon R2 star-forming region. The CO+ emission presents a clumpy ring-like morphology, arising from a narrow dense layer around the HII region. We compare the CO+ distribution with other species present in photon-dominated regions (PDR), such as [CII] 158 µm, H2 S(3) rotational line at 9.3 µm, polycyclic aromatic hydrocarbons (PAHs) and HCO+. We find that the CO+ emission is spatially coincident with the PAHs and [CII] emission. This confirms that the CO+ emission arises from a narrow dense layer of the HI/H2 interface. We have determined the CO+ fractional abundance, relative to C+ toward three positions. The abundances range from 0.1 to 1.9 ×10−10 and are in good agreement with previous chemical model, which predicts that the production of CO+ in PDRs only occurs in dense regions with high UV fields. The CO+ linewidth is larger than those found in molecular gas tracers, and their central velocity are blue-shifted with respect to the molecular gas velocity. We interpret this as a hint that the CO+ is probing photo-evaporating clump surfaces. PMID:27721515

  19. The first CO(+) image: I. Probing the HI/H2 layer around the ultracompact HII region Mon R2.

    PubMed

    Treviño-Morales, S P; Fuente, A; Sánchez-Monge, Á; Pilleri, P; Goicoechea, J R; Ossenkopf-Okada, V; Roueff, E; Rizzo, J R; Gerin, M; Berné, O; Cernicharo, J; Gónzalez-García, M; Kramer, C; García-Burillo, S; Pety, J

    2016-09-15

    The CO(+) reactive ion is thought to be a tracer of the boundary between a HII region and the hot molecular gas. In this study, we present the spatial distribution of the CO(+) rotational emission toward the Mon R2 star-forming region. The CO(+) emission presents a clumpy ring-like morphology, arising from a narrow dense layer around the HII region. We compare the CO(+) distribution with other species present in photon-dominated regions (PDR), such as [CII] 158 µm, H2 S(3) rotational line at 9.3 µm, polycyclic aromatic hydrocarbons (PAHs) and HCO(+). We find that the CO(+) emission is spatially coincident with the PAHs and [CII] emission. This confirms that the CO(+) emission arises from a narrow dense layer of the HI/H2 interface. We have determined the CO(+) fractional abundance, relative to C(+) toward three positions. The abundances range from 0.1 to 1.9 ×10(-10) and are in good agreement with previous chemical model, which predicts that the production of CO(+) in PDRs only occurs in dense regions with high UV fields. The CO(+) linewidth is larger than those found in molecular gas tracers, and their central velocity are blue-shifted with respect to the molecular gas velocity. We interpret this as a hint that the CO(+) is probing photo-evaporating clump surfaces.

  20. Chemical behavior of the dwarf irregular galaxy NGC6822. Its PN and HII region abundances

    NASA Astrophysics Data System (ADS)

    Hernández-Martínez, L.; Peña, M.; Carigi, L.; García-Rojas, J.

    2009-10-01

    Aims: We aim to derive the chemical behavior of a significant sample of PNe and HII regions in the irregular galaxy NGC 6822. The selected objects are distributed in different zones of the galaxy. Our purpose is to obtain the chemical abundances of the present interstellar medium (ISM), represented by H ii regions, and the corresponding values at the time of formation of PNe. With these data the chemical homogeneity of NGC 6822 were tested and the abundance pattern given by H ii regions and PNe used as an observational constraint for computing chemical evolution models to infer the chemical history of NGC 6822. Methods: Due to the faintness of PNe and H ii regions in NGC 6822, to gather spectroscopic data with large telescopes is necessary. We obtained a well suited sample of spectra by employing VLT-FORS 2 and Gemini-GMOS spectrographs. Ionic and total abundances were calculated for the objects where electron temperatures could determined through the detection of [O iii] λ4363 or/and [N ii] λ5755 lines. A “simple” chemical evolution model was developed and the observed data were used to compute a model for NGC 6822 in order to infer a preliminary chemical history in this galaxy. Results: Confident determinations of He, O, N, Ne, S and Ar abundances were derived for a sample of 11 PNe and one H ii region. We confirm that the present ISM is chemically homogeneous, at least in the central 2 kpc of the galaxy, showing a value 12 + log O/H = 8.06 ± 0.04. From the abundance pattern of PNe, we identified two populations: a group of young PNe with abundances similar to H ii regions and a group of older objects with abundances a factor of two lower. A pair of extreme Type I PNe were found. No third dredge-up O enrichement was detected in PNe of this galaxy. The abundance determinations allow us to discuss the chemical behavior of the present and past ISM in NGC 6822. Our preliminary chemical evolution model predicts that an important gas-mass loss occurred during

  1. The Carina Nebula and Gum 31 molecular complex - I. Molecular gas distribution, column densities, and dust temperatures

    NASA Astrophysics Data System (ADS)

    Rebolledo, David; Burton, Michael; Green, Anne; Braiding, Catherine; Molinari, Sergio; Wong, Graeme; Blackwell, Rebecca; Elia, Davide; Schisano, Eugenio

    2016-03-01

    We report high-resolution observations of the 12CO(1-0) and 13CO(1-0) molecular lines in the Carina Nebula and the Gum 31 region obtained with the 22-m Mopra telescope as part of The Mopra Southern Galactic Plane CO Survey. We cover 8 deg2 from l = 285° to 290°, and from b = -1.5° to +0.5°. The molecular gas column density distributions from both tracers have a similar range of values. By fitting a grey-body function to the observed infrared spectral energy distribution from Herschel maps, we derive gas column densities and dust temperatures. The gas column density has values in the range from 6.3 × 1020 to 1.4 × 1023 cm-2, while the dust temperature has values in the range from 17 to 43 K. The gas column density derived from the dust emission is approximately described by a lognormal function for a limited range of column densities. A high-column-density tail is clearly evident for the gas column density distribution, which appears to be a common feature in regions with active star formation. There are regional variations in the fraction of the mass recovered by the CO emission lines with respect to the total mass traced by the dust emission. These variations may be related to changes in the radiation field strength, variation of the atomic to molecular gas fraction across the observed region, differences in the CO molecule abundance with respect to H2, and evolutionary stage differences of the molecular clouds that compose the Carina Nebula-Gum 31 complex.

  2. Far-infrared emission, gas, and ultraluminous HII regions in M101

    NASA Astrophysics Data System (ADS)

    Kenney, J. D. P.; Scoville, N. Z.

    We have made deconvolved maps of M101 in each of the 4 IRAS bands using a new maximum-entropy based model for reconstructing distributions with correlated structure on multiple scales. This new deconvolution procedure, developed by Weir (1992, J.Opt.Soc.Am., submitted), is superior to other maximum entropy-based techniques for several reasons. For our purposes, an important advantage is that it has less artifacts and greatly reduced systematic biases compared with the 'HiRes' maps of M101 produced by Aumann, Fowler, and Melnyk (1990, AJ, 99, 1674), thus it is accurate enough to perform aperture photometry. The deconvolved maps have a maximum resolution of approximately 30 sec, sufficient to resolve the brightest HII complexes and much of the spiral structure. The new maps and our comparison of the far-infrared, gas, and optical distributions are being written up in Kenney, Weir & Scoville (1992, in preparation). The quality of the reconstructed far-infrared maps is good enough for us to carry out most of the analyses outlined in the original proposal. From a ratio of the 60 micron and 100 micron maps, we have found that the ultraluminous HII complexes in the outer galaxy have the hottest dust temperatures with T approximately 50-60 K, which is twice as hot as most of the disk. Their extraordinary luminosity in the far-infrared is due to a relatively small amount of dust being heated to high temperatures, rather than a large concentration of dust and gas. A map of the dust opacity at 60 microns shows good overall agreement with a map of cold gas (HI+H2), indicating that throughout most of the galaxy only approximately 20 percent of the dust is warm enough to be detected by IRAS. The ultraluminous HII complexes have a high luminosity-to-gas mass ratio, independent of whether the far-infrared or the H-alpha emission line is used to measure the luminosity, which implies that gas is being converted into high mass stars more rapidly in these complexes compared to other

  3. HI 21cm Observations of the Supernova Remnant PKS0607+17 and the HII Region S261

    NASA Astrophysics Data System (ADS)

    Chang, Myung Soon; Koo, Bon-Chul

    1997-12-01

    We carried out high-resolution(FWHM=3'.3) HI 21cm observations of the supernova remnant(SNR) PKS0607+17 and HII region S261 using Arecibo 305m telescope. The observation was to investigate whether the high-velocity(HV) gas detected in the southern area of PKS0607+17 by Koo & Heiles(1991) is physically associated with the SNR or not. The velocity of the HV gas ranges from +64km/s to +87km/s, which is difficult to result from the Galactic rotation. The HV gas could be the gas accelerated by supernova blast wave. However, because the observation of Koo and Heiles(1991) was carried out using Hat Creek radio telescope(FWHM=~ 36'), the association of the HV gas with the SNR could not be investigated. Using the Arecibo HI 21cm data, we have found that the HV gas appears in the southern part of the SNR and its velocity ranges from +61km/s to +77km/s. But the HV gas is scattered in the whole field, not only toward PKS0607+17 but also outside the SNR. Accordingly the HV gas is probably not associated with the SNR, but is accidentally aligned along the same line of sight toward the SNR. Instead we have found that HI clouds at low velocities could be possibly associated with the SNR. In Arecibo HI 21cm channel maps the HI gas seems to surround the southern boundary of the SNR at VLSR=+19.6~+40.2km/s. But because the region of the Arecibo HI 21cm observation is not wide enough to examine the HI gas distribution, we investigated this area using the Berkeley low-latitude HI survey data(Weaver & Williams 1974) too. There we found HI gas surrounding the radio continuum boundary of PKS0607+17 at VLSR= +21.6 - +25.8km/s. It is possible that this HI gas is associated with the SNR, in which case, the velocity of the SNR V_o =~ +26km/s, its distance d=~12.5kpc, and its radius R=~145pc. If we assume that the expansion velocity is ~10km/s, then the age of the SNR is ~4.4x10e6 years. PKS0607+17 could be one of the oldest SNRs in the Galaxy. We also studied HI properties of the HII region S

  4. The Lin-Shu type density wave structure of our Galaxy: line-of-sight velocities of 396 HII regions

    NASA Astrophysics Data System (ADS)

    Griv, E.; Hou, L.-G.; Jiang, I.-G.

    2015-11-01

    In this fifth paper in a series, we check again the Lin-Shu idea of small-amplitude density waves in our Galaxy. The updated catalogue of Galactic objects of Hou and Han (Hou and Han in Astron Astrophys 569:125-146, 2014), available in the literature, is used. The line-of-sight velocity field of 396 HII regions with known trigonometric or photometric distances and their uncertainties within 4 kpc from the Sun is investigated in terms of a wave perturbation. Our previous study is enlarged by examining the secondary minima of the residual sum of squares of the predicted and measured velocities of a sample of objects in a considerable region surrounding the Sun. Both the geometrical and physical parameters of the wave pattern are evaluated. Here we show, for the first time, that the local Cygnus-Orion spiral arm, where the Sun is located, does form a part of the major density wave structure of the system under the question but is not a spur originating at the inner Carina-Sagittarius arm or at the outer Perseus arm.

  5. Integral field spectroscopy of the two complexes of HII regions in the main galaxy of the minor merger AM2306-721

    NASA Astrophysics Data System (ADS)

    Hernandez-Jimenez, J. A.; Pastoriza, G.; Sanmartim, D.; Winge, C.; Bonatto, C.; Krabbe, A. C.; Rodrigues, I.

    2017-07-01

    We present a study of two complexes of HII regions in the main galaxy of minor merger AM 2306-721. The observations were obtained with the GMOS-IFU on the Gemini South telescope. By using different discrimination criteria, we determined that shock-ionized gas fraction ranges between 0% and 35%, which are in good agreement with numerical models. Thus, we conclude that almost all the mechanical energy from stellar winds and supernovae is being irradiated.

  6. VizieR Online Data Catalog: IRX-β relation of HII regions in NGC628 (Ye+, 2016)

    NASA Astrophysics Data System (ADS)

    Ye, C.; Zou, H.; Lin, L.; Lian, J.; Hu, N.; Kong, X.

    2016-10-01

    NGC 628 has been observed by the PPAK IFS Nearby Galaxies Survey (PINGS) performed by the 3.5m telescope of the Calar Alto Observatory. The IFU provides a sampling of 2.7", an optical wavelength range of 3700-7000Å with a spectral resolution of ~8Å. The final data set comprises 11094 individual spectra, and the typical spatial resolution is about 3.5"-4". The slice image at the Hα wavelength is used to determine HII regions. FUV and near-UV (NUV) images of NGC 628 were taken by the Galaxy Evolution Explorer (GALEX), which are centered at wavelengths of 1516 and 2267Å. IR images were taken by Spitzer IRAC (3.6um, 8.0um) and MIPS (24um). The spatial resolutions of UV and IR images are 4.3", 5.3", 1.9", 2.8", and 6.4", respectively. We obtain these images from the data release website of Local Volume Legacy (LVL) survey DR5 (Dale+, 2009, J/ApJ/703/517; http://irsa.ipac.caltech.edu/data/SPITZER/LVL/). (2 data files).

  7. Mapping of transfer and H pilus coding regions of the IncHII plasmid pHH1508a.

    PubMed

    Yan, W; Taylor, D E

    1989-02-01

    The IncHII plasmid pHH1508a (208 kilobases) encodes resistance to potassium tellurite, trimethoprim, and streptomycin. Conjugative pili encoded by pHH1508a were isolated, purified, and used for preparation of anti-H pilus antiserum. Immuno-gold labelling experiments using H pilus specific antiserum showed that antigenic determinants were located along the entire length of the H pilus. Immuno-gold labelling and lysis studies using pilH alpha, a bacteriophage specific for H pili, were used to investigate transfer-deficient mutants of pHH1508a obtained by Tn5 mutagenesis and an in vitro constructed derivative of 96 kilobases, pDT1178, which also conferred resistance to potassium tellurite, trimethoprim, and streptomycin. The transfer-deficient mutants did not specify H pili, whereas pDT1178, which transferred at low frequency (1 x 10(-4) transconjugants per recipient), specified a small number of H pili. A naturally occurring plasmid, pMG110, was found to encode the production of H pili, but was completely transfer deficient (less than 1 x 10(-7) transconjugants per recipient). This study suggests that genes required for H pilus production and assembly as well as low level transfer are located separately within the 96-kilobase fragment of pDT1178 and that other genes, located outside this region, are essential for the regulation and full expression of conjugative transfer.

  8. Narrow-band photographic observations of the HII Region S296 in Canis Major

    NASA Astrophysics Data System (ADS)

    Kogure, T.; Yoshida, S.; Wiramihardja, S. D.; Nakano, M.; Sakka, K.

    1988-03-01

    The monochromatic images of the H II region S296 taken with the UK Schmidt telescope at the emission lines Hα+[N II], [S II], [O III], and [O II] are presented, together with some composite images. Based on these photographic images, the overall ionization structure of the H II region is briefly considered.

  9. VizieR Online Data Catalog: Long slit spectroscopy of HII regions (Marquez+, 2004)

    NASA Astrophysics Data System (ADS)

    Marquez, I.; Durret, F.; Masegosa, J.; Moles, M.; Varela, J.; Gonzalez Delgado, R. M.; Maza, J.; Perez, E.; Roth, M.

    2003-11-01

    We present the kinematical data obtained for a sample of active (Seyfert) and non active isolated spiral galaxies, based on long slit spectra along several position angles in the Hα line region and, in some cases, in the Ca triplet region as well. Gas velocity distributions are presented, together with a simple circular rotation model that allows us to determine the kinematical major axes. Stellar velocity distributions are also shown. (1 data file).

  10. The Orion HII Region and the Orion Bar in the Mid-infrared

    NASA Astrophysics Data System (ADS)

    Salgado, F.; Berné, O.; Adams, J. D.; Herter, T. L.; Keller, L. D.; Tielens, A. G. G. M.

    2016-10-01

    We present mid-infrared photometry of the Orion bar obtained with the Faint Object infraRed Camera for the SOFIA Telescope (FORCAST) on board SOFIA at 6.4, 6.6, 7.7, 19.7, 31.5, and 37.1 μm. By complementing this observation with archival FORCAST and Herschel/PACS images, we are able to construct a complete infrared spectral energy distribution of the Huygens region in the Orion nebula. Comparing the infrared images with gas tracers, we find that PACS maps trace the molecular cloud, while the FORCAST data trace the photodissociation region (PDR) and the H ii region. Analysis of the energetics of the region reveal that the PDR extends for 0.28 pc along the line of sight and that the bar is inclined at an angle of 4°. The infrared and submillimeter images reveal that the Orion bar represents a swept-up shell with a thickness of 0.1 pc. The mass of the shell implies a shock velocity of ≃3 km s-1 and an age of ≃105 years for the H ii region. Our analysis shows that the UV and infrared dust opacities in the H ii region and the PDR are a factor 5 to 10 lower than in the diffuse interstellar medium. In the ionized gas, Lyα photons are a major source of dust heating at distances larger than ≃0.06 pc from θ 1 Ori C. Dust temperatures can be explained if the size of the grains is between 0.1 and 1 μm. We derive the photoelectric heating efficiency of the atomic gas in the Orion bar. The results are in good qualitative agreement with models and the quantitative differences indicate a decreased polycyclic aromatic hydrocarbon abundance in this region.

  11. The effect of massive stars on the ionized medium of extragalactic HII regions

    NASA Technical Reports Server (NTRS)

    Castaneda, Hector O.

    1993-01-01

    Giant extragalactic H2 regions (GEHR) are centers of active star formation, ionized by populous clusters of OB stars. These objects are characterized by their low electron density, linear dimensions of order of 10(exp 2) - 10(exp 3) pc, varied morphology, and inhomogeneous distribution of the gas. They are ideal laboratories to study the processes of interaction between the gas and the stars, that could then be extended to the study of H2 and starburst galaxies. An observational program on a selected group of giant H2 regions with the use of one- and two-dimensional spectroscopy is being conducted. Our aim is two-fold: to understand the internal structure of the regions and to study the kinematics and dynamics of the ionized gas. A short report of our ongoing research is presented.

  12. Populations of High-Luminosity Density-Bounded HII Regions in Spiral Galaxies? Evidence and Implications

    NASA Technical Reports Server (NTRS)

    Beckman, J. E.; Rozas, M.; Zurita, A.; Watson, R. A.; Knapen, J. H.

    2000-01-01

    In this paper we present evidence that the H II regions of high luminosity in disk galaxies may be density bounded, so that a significant fraction of the ionizing photons emitted by their exciting OB stars escape from the regions. The key piece of evidence is the presence, in the Ha luminosity functions (LFs) of the populations of H iI regions, of glitches, local sharp peaks at an apparently invariant luminosity, defined as the Stromgren luminosity Lstr), LH(sub alpha) = Lstr = 10(sup 38.6) (+/- 10(sup 0.1)) erg/ s (no other peaks are found in any of the LFs) accompanying a steepening of slope for LH(sub alpha) greater than Lstr This behavior is readily explicable via a physical model whose basic premises are: (a) the transition at LH(sub alpha) = Lstr marks a change from essentially ionization bounding at low luminosities to density bounding at higher values, (b) for this to occur the law relating stellar mass in massive star-forming clouds to the mass of the placental cloud must be such that the ionizing photon flux produced within the cloud is a function which rises more steeply than the mass of the cloud. Supporting evidence for the hypothesis of this transition is also presented: measurements of the central surface brightnesses of H II regions for LH(sub alpha) less than Lstr are proportional to L(sup 1/3, sub H(sub alpha)), expected for ionization bounding, but show a sharp trend to a steeper dependence for LH(sub alpha) greater than Lstr, and the observed relation between the internal turbulence velocity parameter, sigma, and the luminosity, L, at high luminosities, can be well explained if these regions are density bounded. If confirmed, the density-bounding hypothesis would have a number of interesting implications. It would imply that the density-bounded regions were the main sources of the photons which ionize the diffuse gas in disk galaxies. Our estimates, based on the hypothesis, indicate that these regions emit sufficient Lyman continuum not only to

  13. VizieR Online Data Catalog: Radio observations of Galactic WISE HII regions (Anderson+, 2015)

    NASA Astrophysics Data System (ADS)

    Anderson, L. D.; Armentrout, W. P.; Johnstone, B. M.; Bania, T. M.; Balser, D. S.; Wenger, T. V.; Cunningham, V.

    2016-01-01

    We draw our targets from the MIR objects in the WISE catalog of Anderson+, 2014, J/ApJS/212/1. We also include in our sample Sharpless H II regions (Sharpless 1959, VII/20). See section 2 for further details. Our observations were made with the GBT 100m telescope from 2012 July through 2014 August. There are seven radio recombination lines (RRLs) that can be cleanly observed simultaneously with the GBT in the X-band: H87α to H93α. We average these seven RRLs (each at two orthogonal polarizations) to create a single average RRL spectrum. We followed the same GBT observational procedure as in the original HRDS (Green Bank Telescope H II Region Discovery Survey (GBT HRDS; Bania et al. 2010ApJ...718L.106B). (3 data files).

  14. VizieR Online Data Catalog: Hα in HII regions in spiral galaxies (Marquez+, 2002)

    NASA Astrophysics Data System (ADS)

    Marquez, I.; Masegosa, J.; Moles, M.; Varela, J.; Bettoni, D.; Galletta, G.

    2002-07-01

    In this paper we study long slit spectra in the region of Hα emission line of a sample of 111 spiral galaxies with recognizable and well defined spiral morphology and with a well determined environmental status, ranging from isolation to non-disruptive interaction with satellites or companions. The form and properties of the rotation curves are considered as a function of the isolation degree, morphological type and luminosity. The line ratios are used to estimate the metallicity of all the detected H II regions, thus producing a composite metallicity profile for different types of spirals. We have found that isolated galaxies tend to be of later types and lower luminosity than the interacting galaxies. The outer parts of the rotation curves of isolated galaxies tend to be flatter than in interacting galaxies, but they show similar relations between global parameters. The scatter of the Tully-Fisher relation defined by isolated galaxies is significantly lower than that of interacting galaxies. The [NII]/Hα ratios, used as a metallicity indicator, show a clear trend between Z and morphological type, t, with earlier spirals showing higher ratios; this trend is tighter when instead of t the gradient of the inner rotation curve, G, is used; no trend is found with the change in interaction status. The Z-gradient of the disks depends on the type, being almost flat for early spirals, and increasing for later types. The [NII]/Hα ratios measured for disk H II regions of interacting galaxies are higher than for normal/isolated objects, even if all the galaxy families present similar distributions of Hα equivalent width. (1 data file).

  15. On the Relationship of UC HII Regions and Class II Methanol Masers. I. Source Catalogs

    NASA Astrophysics Data System (ADS)

    Hu, B.; Menten, K. M.; Wu, Y.; Bartkiewicz, A.; Rygl, K.; Reid, M. J.; Urquhart, J. S.; Zheng, X.

    2016-12-01

    We conducted Very Large Array C-configuration observations to measure positions and luminosities of Galactic Class II 6.7 GHz methanol masers and their associated ultra-compact H ii regions. The spectral resolution was 3.90625 kHz and the continuum sensitivity reached 45 μJy beam-1. We mapped 372 methanol masers with peak flux densities of more than 2 Jy selected from the literature. Absolute positions have nominal uncertainties of 0.″3. In this first paper on the data analysis, we present three catalogs; the first gives information on the strongest feature of 367 methanol maser sources, and the second provides information on all detected maser spots. The third catalog presents derived data of the 127 radio continuum counterparts associated with maser sources. Our detection rate of radio continuum counterparts toward methanol masers is approximately one-third. Our catalogs list properties including distance, flux density, luminosity, and the distribution in the Galactic plane. We found no significant relationship between luminosities of masers and their associated radio continuum counterparts, however, the detection rate of radio continuum emission toward maser sources increases statistically with the maser luminosities.

  16. The Herschel view of HII regions in M 33 (HERM33ES)

    NASA Astrophysics Data System (ADS)

    Verley, S.; Relaño, M.; Kramer, C.; Xilouris, E. M.; Boquien, M.; Calzetti, D.; Combes, F.; Buchbender, C.; Braine, J.; Quintana-Lacaci, G.; Tabatabaei, F. S.; Lord, S.; Israel, F.; Stacey, G.; van der Werf, P.

    2010-12-01

    Within the framework of the HERM33ES Key Project (Kramer et al. 2010), using the high resolution and sensitivity of the Herschel photometric data, we study the compact emission in the Local Group spiral galaxy M 33. We present a catalogue of 159 compact emission sources in M 33 identified by SExtractor in the 250 μm SPIRE band which is the one that provides the best spatial resolution. We measure fluxes at 24 μm and Hα for those 159 extracted sources. We find a very strong Pearson correlation coefficient with the MIPS 24 μm emission (r24 = 0.94) and a rather strong correlation with the Hα emission, although with more scatter (rHα = 0.83). Due to the very strong link between the 250 μm compact emission and the 24 μm and Hα emissions, by recovering the star formation rate from standard recipes for H II regions, we are able to provide star formation rate calibrations based on the 250 μm compact emission alone. Finally, the morphological study of a set of three Hα shells shows that there is a displacement between far-ultraviolet and the SPIRE bands, while the Hα structure is in general much more coincident with the cool dust.

  17. A Faraday Rotation Investigation to Probe the Shells of HII Regions with Associated Stellar Bubbles%A Costa, Allison H.; Spangler, Steven R.; Sink, Joseph R.

    NASA Astrophysics Data System (ADS)

    Costa, Allison H.; Spangler, Steven R.; Sink, Joseph R.

    2015-01-01

    We performed polarimetric observations with the Very Large Array of 11 extra-galactic radio sources with lines of sight through the shell of the Rosette Nebula (VLA project AS1110). This investigation supplements the study of the shell of the Rosette Nebula by Savage et al. (2013). We utilize two methods for calculating the rotation measure (RM) for the new lines of sight. The first is using the traditional method of least-squares fit to χ(λ2), and the second is using RM Synthesis (Brentjens & Bruyn 2005). We present a comparison of the two methods of obtaining RM values, and we find excellent agreement between the two methods. In addition, we discuss a plasma shell model, which is intended to reproduce the sign and magnitude of the observed RM due to the shell, with a new method of determining the model parameters, such as the inner and outer radii and the electron density, for specific lines of sight. This treatment of the model parameters allows us to extend our investigation to HII regions that do not have spherical symmetry, like the Heart Nebula/W4. We describe a new method of fitting a local shell model to specific lines of sight and then calculating the associated RM. By modeling the magnitude of the RM for specific lines of sight, we can better distinguish between a scenario where an observed excess in RM is due to an amplification of the magnetic field or one where it is exclusively due to an increase in the density of the shell. This research was supported at the University of Iowa by grant AST09-07911 and ATM09-56901 from the National Science Foundation.

  18. Evidence of Short Timescale Flux Density Variations of UC HII Regions in Sgr B2 Main and North

    NASA Astrophysics Data System (ADS)

    De Pree, C. G.; Peters, T.; Mac Low, M. M.; Wilner, D. J.; Goss, W. M.; Galván-Madrid, R.; Keto, E. R.; Klessen, R. S.; Monsrud, A.

    2015-12-01

    We have recently published observations of significant flux density variations at 1.3 cm in H ii regions in the star-forming regions Sgr B2 Main and North. To further study these variations, we have made new 7 mm continuum and recombination line observations of Sgr B2 at the highest possible angular resolution of the Karl G. Jansky Very Large Array (VLA). We have observed Sgr B2 Main and North at 42.9 GHz and at 45.4 GHz in the BnA configuration (Main) and the A configuration (North). We compare these new data to archival VLA 7 mm continuum data of Sgr B2 Main observed in 2003 and Sgr B2 North observed in 2001. We find that 1 of the 41 known ultracompact and hypercompact H ii regions in Sgr B2 (K2-North) has decreased ∼27% in flux density from 142 ± 14 to 103 ± 10 mJy (2.3σ) between 2001 and 2012. A second source, F3c-Main, has increased ∼30% in flux density from 82 ± 8 to 107 ± 11 mJy (1.8σ) between 2003 and 2012. F3c-Main was previously observed to increase in flux density at 1.3 cm over a longer time period between 1989 and 2012. An observation of decreasing flux density, such as that observed in K2-North, is particularly significant since such a change is not predicted by the classical hypothesis of steady expansion of H ii regions during massive star accretion. Our new observations at 7 mm, along with others in the literature, suggest that the formation of massive stars occurs through time-variable and violent accretion.

  19. Spitzer Space Telescope IRS Spectral Mapping of Photoionized Columns in M16 and the Carina HII Regions

    NASA Astrophysics Data System (ADS)

    Cotera, Angela; Simpson, J. P.; Sellgren, K.; Stolovy, S. R.

    2013-01-01

    Photoevaporated columns of dust and gas - also called elephant trunks, pillars or fingers - are found in the periphery of many H II regions. They have been observed within the Galaxy, the SMC and the LMC. These features are thought to be sites of current star formation, but the question remains whether the columns persist because stars formed in the denser regions prior to interactions with the UV radiation and stellar winds of nearby massive stars, or because of core collapse resulting from these interactions. We have obtained Spitzer IRS spectral maps of three columns within M 16 and three columns within the Carina nebula, to test our understanding of the impact on these transitory features of differing stellar populations and initial conditions. We use the wealth of molecular, atomic and PAH emission lines located within the spectral range of the high resolution IRS modes (9.9-37.2 micron) to determine the excitation state, dust and gas temperatures, and probe the shock characteristics within the columns as a function of location. Using the IRS spectral mapping mode, in conjunction with the CUBISM tool and the CLOUDY H II region model code, we have constructed detailed maps of the accessible emission lines and derived parameters for each column. Mapping the distribution of the physical states of the dust and gas in these columns is enhancing our understanding of the competing processes within these dynamic objects. The data presented here represent the only IRS spectral maps of photoionized pillars.

  20. VizieR Online Data Catalog: Bubble HII region Sh2-39 (N5) (Duronea+, 2017)

    NASA Astrophysics Data System (ADS)

    Duronea, N. U.; Cappa, C. E.; Bronfman, L.; Borissova, J.; Gromadzki, M.; Kuhn, M. A.

    2017-06-01

    The molecular observations were carried out in August 2015 with the 10m Atacama Submillimeter Telescope Experiment (ASTE). We used DASH345, a two sideband single-polarization heterodyne receiver, tunable in LO frequency range from 327GHz to 370GHz at observable frequency range from 321GHz to 376GHz. The XF digital spectrometer was set to a bandwidth and spectral resolution of 128MHz and 125KHz, respectively. The spectral velocity resolution was 0.11km/s, the half power beamwidth (HPBW) is ~22", and the main beam efficiency (mb) is 0.65. Observations were made using the on-the-fly (OTF) mode with two orthogonal scan directions along RA and Dec. (J2000) centered on RA, Dec.(J2000)= (18:17:02.1, -18:40:19). We observed simultaneously the lines CO(3-2) (345.796GHz) and HCO+(4-3) (356.734) in a region of ~17'x17' (see Fig. 1). The spectra were reduced with NOSTAR2 using the standard procedure. The brightest star projected at the center of [BDS2003] 6 (2MASS J18165113-1841488) was observed on August 2016 with Astronomy Research using the Cornell Infra Red Imaging Spectrograph (ARCoIRIS), a cross-dispersed, single-object, longslit, infrared imaging spectrograph,mounted on Blanco 4-m Telescope, CTIO. The spectra cover a simultaneous wavelength range of 0.80 to 2.47um, at a spectral resolution of about 3500 λ{δλ, encompassing the entire zYJHK photometric range. The spectrum was taken with 480 sec integration time, at 1.03 average airmass. The HD163336 telluric A0 V standard is observed immediately after target. The basic steps of the reduction procedure are described in Chene et al. (2012A&A...545A..54C, Cat. J/A+A/545/A54, 2013A&A...549A..98C). We used the corresponding pipeline. (3 data files).

  1. Heavy Ions In Space (HIIS) experiment

    NASA Technical Reports Server (NTRS)

    Adams, James H., Jr.; Beahm, Lorraine P.; Tylka, Allan J.

    1992-01-01

    The Heavy Ions In Space (HIIS) experiment has two primary objectives: (1) to measure the elemental composition of ultraheavy Galactic cosmic rays, beginning in the tin-barium region of the periodic table; and (2) to study heavy ions which arrive at LDEF below the geomagnetic cutoff, either because they are not fully stripped of electrons or because their source is within the magnetosphere. Both have practical as well as astrophysical consequences. The HIIS experiment used eight thick stacks of plastic track detectors mounted in two trays on the space facing end of LDEF. Since the last LDEF symposium, the statistics were increased of the observations and have extended the analysis to a second stack and to detector sheets near the top of a stack. New results are reported on the detector resolution and on the observations of both stopping and relativistic particles.

  2. The critical density for star formation in HII galaxies

    NASA Astrophysics Data System (ADS)

    Taylor, Christopher L.; Brinks, Elias; Skillman, Evan D.

    1993-01-01

    The star formation rate (SFR) in galaxies is believed to obey a power law relation with local gas density, first proposed by Schmidt (1959). Kennicutt (1989) has shown that there is a threshold density above which star formation occurs, and for densities at or near the threshold density, the DFR is highly non-linear, leading to bursts of star formation. Skillman (1987) empirically determined this threshold for dwarf galaxies to be approximately 1 x 10(exp 21) cm(exp -2), at a linear resolution of 500pc. During the course of our survey for HI companion clouds to HII galaxies, we obtained high resolution HI observations of five nearby HII galaxies. HII galaxies are low surface brightness, rich in HI, and contain one or a few high surface brightness knots whose optical spectra resemble those of HII regions. These knots are currently experiencing a burst of star formation. After Kennicutt (1989) we determine the critical density for star formation in the galaxies, and compare the predictions with radio and optical data.

  3. Progress report on the Heavy Ions in Space (HIIS) experiment

    NASA Technical Reports Server (NTRS)

    Adams, James H., Jr.; Beahm, Lorraine P.; Boberg, Paul R.; Tylka, Allan J.

    1993-01-01

    One of the objectives of the Heavy Ions In Space (HIIS) experiment is to investigate heavy ions which appear at Long Duration Exposure Facility (LDEF) below the geomagnetic cutoff for fully-ionized galactic cosmic rays. Possible sources of such 'below-cutoff' particles are partially-ionized solar energetic particles, the anomalous component of cosmic rays, and magnetospherically-trapped particles. In recent years, there have also been reports of below-cutoff ions which do not appear to be from any known source. Although most of these observations are based on only a handful of ions, they have led to speculation about 'partially-ionized galactic cosmic rays' and 'near-by cosmic ray sources'. The collecting power of HIIS is order of magnitude larger than that of the instruments which reported these results, so HIIS should be able to confirm these observations and perhaps discover the source of these particles. Preliminary results on below-cutoff heavy-ions are reported. Observations to possible known sources of such ions are compared. A second objective of the HIIS experiment is to measure the elemental composition of ultraheavy galactic cosmic rays, beginning in the tin-barium region of the periodic table. A report on the status of this analysis is presented.

  4. A Survey of a Complete Sample of HII Galaxies to Detect HI Companions

    NASA Astrophysics Data System (ADS)

    Taylor, C. L.; Brinks, E.; Skillman, E. D.

    1993-12-01

    \\HII\\ Galaxies are \\HI\\ rich galaxies which contain one or a few high surface brightness optical knots whose spectra resemble those of \\HII\\ regions. These knots are areas of intense star formation. The current star formation rates are too high to last a Hubble time, leading to the hypothesis that \\HII\\ galaxies undergo star formation in discrete bursts. (Searle & Sargent, 1972, ApJ 173, p. 25) One possible explanation for this phenomenon is that a gravitational interaction triggers the burst of star formation in an otherwise quiescent galaxy. Taylor, Brinks, & Skillman (1993, AJ 105, p. 128) mapped in \\HI\\ 9 isolated \\HII\\ galaxies with the VLA in its most compact configuration. Five \\HI\\ companions were discovered near four of the \\HII\\ galaxies. These \\HI\\ companions were within a radius of 30 arcmin and within 240 \\kms. The companions were typically one order of magnitude smaller than their parent galaxies in both neutral hydrogen and total mass. Motivated by this success, we have obtained 21-cm VLA observations of a complete, volume limited sample of \\HII\\ galaxies without obvious interaction partners. The current sample consists of nineteen members with velocities less than 2500 \\kms. From our observations we have positively identified 10 companions around 8 galaxies, plus a further four sample members which are gravitationaly interacting with nearby sample members, for a total of at least 12 interacting systems. A preliminary analysis of these objects and the statistical significance of the detection rate will be discussed.

  5. A Survey of a Complete Sample of HII Galaxies to Detect HI Companions

    NASA Astrophysics Data System (ADS)

    Taylor, C. L.; Skillman, E. D.; Brinks, E.

    1992-12-01

    HII Galaxies are HI rich galaxies which contain one or a few high surface brightness optical knots whose spectra resemble those of HII regions. These knots are areas of intense star formation. The current star formation rates are too high to last a Hubble time, leading to the hypothesis that HII galaxies undergo star formation in discrete bursts. One possible explanation for this phenomenon is that a gravitational interaction triggers the burst of star formation in an otherwise quiescent galaxy. Taylor, Brinks, and Skillman (1993, AJ in press) mapped in HI 9 isolated HII galaxies with the VLA in its most compact configuration. Five HI companions were discovered near four of the HII galaxies. These HI companions were within a radius of 30 arcmin and within 240 km/s. The companions were typically one order of magnitude smaller than their parent galaxies in both neutral hydrogen and total mass. Motivated by this success, we have obtained 21-cm VLA observations of a complete, volume limited sample of HII galaxies without obvious interaction partners. The current sample consists of nineteen members with velocities less than 2500 km/s. From our observations we have positively identified five companions, and are investigating seven more potential detections. A preliminary analysis of the these objects, and the statistical significance of the detection rate, are presented.

  6. The dielectric study of insulin-loaded reverse hexagonal (H(II)) liquid crystals.

    PubMed

    Mishraki-Berkowitz, T; Ben Ishai, P; Aserin, A; Feldman, Yu; Garti, N

    2015-04-14

    The dielectric behavior of the insulin-loaded HII mesophase (containing GMO-TAG-water-glycerol-insulin) was studied using two empty reference systems (GMO-TAG-water and GMO-TAG-water-glycerol) at a frequency range of 10(-2)-10(6) Hz, and a temperature range of 290-333 K. Three clearly defined relaxation processes were observed and assigned to the reorientation of GMO polar heads, the tangential movement of counterions at the interface, and the movements of TAGs through the lipid tail. Upon addition of glycerol, a heterogeneous inner structure was formed within the HII cylinders: the water-glycerol core surrounded by a water rigid layer. Upon heating, two critical points were detected referring to the dehydration of the GMO heads (at 304 K, similar to the water-filled HII system) and to energetic modifications (at 316 K), resulting in breaking of the water layer allowing on-demand controlled release. Insulin incorporation combined the features of both reference HII systems. Yet, unlike the empty HII systems, insulin perturbed the GMO-water interface while decreasing the movement of the GMO headgroup, and reducing T0 (296 K). No interactions were formed between the dipole of each counterion at the interface region and the matrix (the GMO), fitting the Debye process. Dynamic behavior was observed, pointing to mobility between the hexagonal rods themselves, enabling controlled release from the HII carrier.

  7. Solubilization of vitamin E into H(II) LLC mesophase in the presence and in the absence of vitamin C.

    PubMed

    Bitan-Cherbakovsky, Liron; Yuli-Amar, Idit; Aserin, Abraham; Garti, Nissim

    2010-03-02

    The synergistic solubilization of two major hydrophilic (vitamin C, ascorbic acid, AA) and lipophilic (vitamin E, D-alpha-tocopherol, VE) antioxidants within reverse hexagonal (H(II)) mesophases is reported. The H(II) mesophases are composed of monoolein (GMO)/VE/AA/water. A wide range of VE concentration was examined (on the expense of GMO concentrations) while the AA and water concentrations remained constant (4 and 12.5 wt %, respectively) in order to expand the H(II) mesophase. SAXS and DSC combined with ATR-FTIR techniques were utilized to study the interactions between each solubilizate and the H(II) component that enabled the synergistic accommodation of the hydrophilic and hydrophobic molecules. It was revealed that up to 27 wt % VE solubilized within the H(II) mesophase. This hydrophobic additive localized at the lipophilic GMO tail region solvating the surfactant tails, thereby enabling the formation of the H(II) structure. As a result, the lattice parameter and the melting point of the hydrophobic tails decreased. Above 27 wt % VE (up to 33 wt %), once the GMO lipophilic region was homogenously solvated, additional VE molecules located closer to the interface. At this range of concentrations, new hydrogen bonds between O-H groups of VE and O-H groups of GMO were formed. Once 35 wt % VE was introduced, the H(II) structure transformed to face-centered reverse micellar cubic phase (Fd3m, Q(227)).

  8. Sitios de formación estelar

    NASA Astrophysics Data System (ADS)

    Vasquez, J.

    The cold dust is one of the main components of the IR clumps; where the star formation is begining. In this work; we analized the emission distribution at 870 m of the IR clumps located in HII regions and giant molecular clouds (GMC); based on the HII region Gum31 and the GMCG345.5+1.0; respectively. FULL TEXT IN SPANISH

  9. The initial mass function in HII galaxies

    NASA Technical Reports Server (NTRS)

    Campbell, Alison W.

    1987-01-01

    Observation of a large sample of HII galaxies shows that the emission line ratios of the youngest objects change systematically with gaseous oxygen abundance, which was interpreted as resulting from changes in the initial mass function (IMF) of the ionizing cluster. Comparison with cluster/nebula models shows that both the slope and the upper mass limit of the cluster IMF vary with abundance. In HII galaxies with oxygen abundance about 1/10 that of Orion, the IMF for massive stars must have a slope which is about a factor of 2 smaller than in the Solar Neighborhood.

  10. Different structures formed at HII boundaries

    NASA Astrophysics Data System (ADS)

    Miao, Jingqi; Cornwall, Paul; Kinnear, Tim

    2015-03-01

    Hydrodynamic simulations on the evolution of molecular clouds (MCs) at HII boundaries are used to show that radiation driven implosion (RDI) model can create almost all of the different morphological structures, such as a single bright-rimmed cloud (BRC), fragment structure and multiple elephant trunk (ET) structures.

  11. The L-σ relation for HII galaxies in green

    NASA Astrophysics Data System (ADS)

    Melnick, J.; Telles, E.; Bordalo, V.; Chávez, R.; Fernández-Arenas, D.; Terlevich, E.; Terlevich, R.; Bresolin, F.; Plionis, M.; Basilakos, S.

    2017-03-01

    The correlation between emission-line luminosity (L) and profile-width (σ) for HII galaxies provides a powerful method to measure the distances to galaxies over a wide range of redshifts. In this paper, we use SDSS spectrophotometry to explore the systematics of the correlation using the [OIII]5007 lines instead of Hα or Hβ to measure luminosities and line widths. We also examine possible systematic effects involved in measuring the profile-widths and the luminosities through different apertures. We find that the green L-σ relation, defined using [OIII]5007 luminosities, is significantly more sensitive than Hβ to the effects of age and the physical conditions of the nebulae, which more than offsets the advantage of the higher strength of the [OIII]5007 lines. We then explore the possibility of mixing [OIII]5007 profile-widths with SDSS Hβ luminosities using the Hubble constant H0 to quantify the possible systematic effects. We find the mixed L(Hβ) - σ[OIII] relation to be at least as powerful as the canonical L-σ relation as a distance estimator, and we show that evolutionary corrections do not change the slope and the scatter of the correlation and, therefore, do not bias the L-σ distance indicator at high redshifts. Locally, however, the luminosities of the giant HII regions that provide the zero-point calibrators are sensitive to evolutionary corrections and may bias the Hubble constant if their mean ages, as measured by the equivalent widths of Hβ, are significantly different from the mean age of the HII galaxies. Using a small sample of 16 ad-hoc zero point calibrators we obtain a value of H0 = 66.4+ 5.0-4.5km s-1 Mpc-1 for the Hubble constant, which is fully consistent with the best modern determinations, and which is not biased by evolutionary corrections.

  12. Penetratin-induced transdermal delivery from H(II) mesophases of sodium diclofenac.

    PubMed

    Cohen-Avrahami, Marganit; Libster, Dima; Aserin, Abraham; Garti, Nissim

    2012-05-10

    Penetratin, a cell penetrating peptide is embedded within a reversed hexagonal (H(II)) mesophase for improved transdermal delivery of sodium diclofenac (Na-DFC). The H(II) mesophase serves as the solubilization reservoir and gel matrix whereas penetratin is the transdermal penetration enhancer for the drug. The systems were characterized and the interactions between the components were determined by SAXS, ATR-FTIR and SD-NMR. High affinity of Na-DFC to glycerol monooleate (GMO) was revealed, associated with increasing the order within the water channels. This affinity is enhanced upon heating and seems to be associated with GMO dehydration. Penetratin (PEN) is entrapped at the hydrophilic region of the H(II) mesophase, between the GMO headgroups, reducing the order of the system and decreasing the size of the hexagonal domains. The transdermal delivery rate of Na-DFC through porcine skin, from the H(II) mesophases, was enhanced by PEN and so also the cumulative transport crossing the skin. PEN induced accelerated drug diffusion through the stratum corneum, towards the different skin layers. The transdermal delivery enhancement is explained from the results of the ATR-FTIR analysis. It seems that PEN accelerates the structural transition of skin lipids from hexagonal to liquid. The disordering results in enhanced diffusion of Na-DFC through the stratum corneum, followed by enhanced overall penetration of the drug. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. VLT/NACO near-infrared imaging and spectroscopy of N159A in the LMC HII complex N159

    NASA Astrophysics Data System (ADS)

    Testor, G.; Lemaire, J. L.; Field, D.; Diana, S.

    2006-07-01

    We present near-infrared imaging and spectrocopic observations of the HII region N159A (~10 pc) in the giant star-forming region N159 (50 pc) in the LMC. N159A was observed in the J and Ks bands at high spatial resolution ~0.2 arcsec using the ESO Very Large Telescope UT4 (VLT), equipped with the NAOS adaptative optics system. Our data reveal the morphology of this region in unprecedented detail. The protostar P2, one of the first YSOs of Class I identified in the LMC is now resolved in two YSO candidates. The ultracompact HII region LI-LMC 1501W is found to be a tight cluster embedded in a compact HII region ionised by a late O source. A new multiple system composed of a tight star cluster and an YSO candidate, all embedded in a compact nebular region (0.4 pc) is also detected at the north-east edge of N159A. The stellar population of the whole N159A region appears composed of two main stellar populations, one with an age ≤3 Myr and the other one with a large range of age (300 Myr-10 Gyr). Using spectroscopy, one of the two exciting O stars in the HII region N159A is classified O5-O6.

  14. Direct measurement of lensing amplification in Abell S1063 using a strongly lensed high redshift HII galaxy

    NASA Astrophysics Data System (ADS)

    Terlevich, Roberto; Melnick, Jorge; Terlevich, Elena; Chávez, Ricardo; Telles, Eduardo; Bresolin, Fabio; Plionis, Manolis; Basilakos, Spyros; Fernández Arenas, David; González Morán, Ana Luisa; Díaz, Ángeles I.; Aretxaga, Itziar

    2016-08-01

    ID11 is an actively star-forming, extremely compact galaxy and Lyα emitter at z = 3.117 that is gravitationally magnified by a factor of ~17 by the cluster of galaxies Hubble Frontier Fields AS1063. The observed properties of this galaxy resemble those of low luminosity HII galaxies or giant HII regions such as 30 Doradus in the Large Magellanic Cloud. Using the tight correlation correlation between the Balmer-line luminosities and the width of the emission lines (typically L(Hβ) - σ(Hβ)), which are valid for HII galaxies and giant HII regions to estimate their total luminosity, we are able to measure the lensing amplification of ID11. We obtain an amplification of 23 ± 11 that is similar within errors to the value of ~17 estimated or predicted by the best lensing models of the massive cluster Abell S1063. We also compiled, from the literature, luminosities and velocity dispersions for a set of lensed compact star-forming regions. There is more scatter in the L-σ correlation for these lensed systems, but on the whole the results tend to support the lensing model estimates of the magnification. Our result indicates that the amplification can be independently measured using the L - σ relation in lensed giant HII regions or HII galaxies. It also supports the suggestion, even if lensing is model dependent, that the L - σ relation is valid for low luminosity high-z objects. Ad hoc observations of lensed star-forming systems are required to determine the lensing amplification accurately.

  15. Starburst in the Interacting HII Galaxy II Zw 40 and in Non-Interacting HII Galaxies

    NASA Astrophysics Data System (ADS)

    Telles, E.

    2010-06-01

    In this poster, I summarize the results of our integral field spectroscopic observations of the nearby prototype of HII galaxies, II Zw 40. Observations with GMOS-IFU on GEMINI-North in the optical allowed us to make a detailed kinematic picture of the central starburst, while SINFONI with adaptive optics on the ESO-VLT gave us a near-IR view of the interplay between the ISM phases. Here, I also address the question that not all starbursts require an external trigger such as a galaxy-galaxy encounter, as it seems to be the case for a fraction of low luminosity HII galaxies. We speculate that these may form stars spontaneously like "popcorn in a pan".

  16. ISS Update: H-II Transfer Vehicle Activities

    NASA Image and Video Library

    NASA Public Affairs Officer Josh Byerly talks with NASA astronaut Cady Coleman about the Japanese H-II Transfer Vehicle. Questions? Ask us on Twitter @NASA_Johnson and include the hashtag #askStati...

  17. Doppler Imaging of Young Late-Type Stars: HII 686, HII 3163, and P1724

    NASA Astrophysics Data System (ADS)

    Stout-Batalha, Natalie Marie

    Maximum entropy image reconstruction (Doppler imaging) is applied to HII 686 (K4V, v sin i=64 km s-1) and HII 3163 (K0, v sin i=70 km s-1), two zero-age main sequence stars of the Pleiades cluster, and the weak-lined T Tauri star Parenago 1724 (K0, v sin i=71 km s-1). Their surface temperature distributions are determined in order to study the nature of magnetic activity in young ultra-fast rotators. Specific intensity line profiles used in the DI algorithm are synthesized. The sensitivity of the reconstructions to the choice of input stellar and atomic data is investigated. The quality of the fit to the average disk integrated line profile is found to be more important to DI analysis than the exact parameters used to generate the fit when the shape of the disk integrated line profile is dominated by rotational broadening. Fifteen absorption lines are used to generate fifteen individual reconstructions of each Pleiades target. Averaging reduces noise in the reconstructions. However, spurious features can persist at sub-observer longitudes. Such 'phase-ghosting' can largely be eliminated by including broad-band photometric observations in the analysis. Using the large number of reconstructions for a given star, uncertainties in the images are estimated. HII 686 shows one predominant feature at 77o latitude which is 700 K cooler than the surrounding photosphere. HII 3163 also shows one predominant feature centered at approximately 70o latitude. A spot temperature 1000 K cooler than the photosphere best reproduces the observations. P1724 shows a predominant feature (or features) centered at 30o latitude which is 800 K cooler than its photosphere. These results are discussed in light of recent theoretical observations and existing image reconstructions of similar objects. No correlations are found among reconstructions which could be attributed to line characteristics: equivalent width, excitation potential or depth of formation. This is also true for the LiI and KI

  18. A Substellar Companion to Pleiades HII 3441

    NASA Technical Reports Server (NTRS)

    Konishi, Mihoko; Matsuo, Taro; Yamamoto, Kodai; Samland, Matthias; Sudo, Jun; Shibai, Hiroshi; Itoh, Yoichi; Fukagawa, Misato; Sumi, Takhiro; Kudo, Tomoyuki; hide

    2016-01-01

    We find a new substellar companion to the Pleiades member star, Pleiades HII 3441, using the Subaru telescope with adaptive optics. The discovery is made as part of the high-contrast imaging survey to search for planetary-mass and substellar companions in the Pleiades and young moving groups. The companion has a projected separation of 0". 49+/-0". 02 (66+/-2 au) and a mass of 68+/-5M(sub J) based on three observations in the J-, H-, and K(sub s)-bands. The spectral type is estimated to be M7 (approx. 2700 K), and thus no methane absorption is detected in the H band. Our Pleiades observations result in the detection of two substellar companions including one previously reported among 20 observed Pleiades stars, and indicate that the fraction of substellar companions in the Pleiades is about 10.0+26.1 -8.8 %. This is consistent with multiplicity studies of both the Pleiades stars and other open clusters.

  19. A substellar companion to Pleiades HII 3441

    NASA Astrophysics Data System (ADS)

    Konishi, Mihoko; Matsuo, Taro; Yamamoto, Kodai; Samland, Matthias; Sudo, Jun; Shibai, Hiroshi; Itoh, Yoichi; Fukagawa, Misato; Sumi, Takahiro; Kudo, Tomoyuki; Hashimoto, Jun; Kuzuhara, Masayuki; Kusakabe, Nobuhiko; Abe, Lyu; Akiyama, Eiji; Brandner, Wolfgang; Brandt, Timothy D.; Carson, Joseph C.; Feldt, Markus; Goto, Miwa; Grady, Carol A.; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko S.; Henning, Thomas; Hodapp, Klaus W.; Ishii, Miki; Iye, Masanori; Janson, Markus; Kandori, Ryo; Knapp, Gillian R.; Kwon, Jungmi; McElwain, Michael W.; Mede, Kyle; Miyama, Shoken; Morino, Jun-Ichi; Moro-Martín, Amaya; Nishimura, Tetsuo; Oh, Daehyeon; Pyo, Tae-Soo; Serabyn, Eugene; Schlieder, Joshua E.; Suenaga, Takuya; Suto, Hiroshi; Suzuki, Ryuji; Takahashi, Yasuhiro H.; Takami, Michihiro; Takato, Naruhisa; Terada, Hiroshi; Thalmann, Christian; Turner, Edwin L.; Watanabe, Makoto; Wisniewski, John P.; Yamada, Toru; Takami, Hideki; Usuda, Tomonori; Tamura, Motohide

    2016-12-01

    We find a new substellar companion to the Pleiades member star, Pleiades HII 3441, using the Subaru telescope with adaptive optics. The discovery is made as part of the high-contrast imaging survey to search for planetary-mass and substellar companions in the Pleiades and young moving groups. The companion has a projected separation of 0{^''.}49 ± 0{^''.}02 (66 ± 2 au) and a mass of 68 ± 5 MJ based on three observations in the J-, H-, and Ks-bands. The spectral type is estimated to be M7 (˜2700 K), and thus no methane absorption is detected in the H band. Our Pleiades observations result in the detection of two substellar companions including one previously reported among 20 observed Pleiades stars, and indicate that the fraction of substellar companions in the Pleiades is about 10.0^{+26.1}_{-8.8}%. This is consistent with multiplicity studies of both the Pleiades stars and other open clusters.

  20. Cloning of the BssHII restriction-modification system in Escherichia coli : BssHII methyltransferase contains circularly permuted cytosine-5 methyltransferase motifs.

    PubMed Central

    Xu, S; Xiao, J; Posfai, J; Maunus, R; Benner, J

    1997-01-01

    BssHII restriction endonuclease cleaves 5'-GCGCGC-3' on double-stranded DNA between the first and second bases to generate a four base 5'overhang. BssHII restriction endonuclease was purified from the native Bacillus stearothermophilus H3 cells and its N-terminal amino acid sequence was determined. Degenerate PCR primers were used to amplify the first 20 codons of the BssHII restriction endonuclease gene. The BssHII restriction endonuclease gene (bssHIIR) and the cognate BssHII methyltransferase gene (bssHIIM) were cloned in Escherichia coli by amplification of Bacillus stearothermophilus genomic DNA using PCR and inverse PCR. BssHII methyltransferase (M.BssHII) contains all 10 conserved cytosine-5 methyltransferase motifs, but motifs IX and X precede motifs I-VIII. Thus, the conserved motifs of M. BssHII are circularly permuted relative to the motif organizations of other cytosine-5 methyltransferases. M.BssHII and the non-cognate multi-specific phiBssHII methyltransferase, M.phiBss HII [Schumann,J. et al . (1995) Gene, 157, 103-104] share 34% identity in amino acid sequences from motifs I-VIII, and 40% identity in motifs IX-X. A conserved arginine is located upstream of a TV dipeptide in the N-terminus of M.BssHII that may be responsible for the recognition of the guanine 5' of the target cytosine. The BssHII restriction endonuclease gene was expressed in E.coli via a T7 expression vector. PMID:9321648

  1. Food volatile compounds facilitating HII mesophase formation: solubilization and stability.

    PubMed

    Amar-Zrihen, Natali; Aserin, Abraham; Garti, Nissim

    2011-05-25

    Four lipophilic food volatile molecules of different chemical characteristics, phenylacetaldehyde, 2,6-dimethyl-5-heptenal, linalool, and trans-4-decenal, were solubilized into binary mixtures of monoolein/water, facilitating the formation of reverse hexagonal (H(II)) mesophases at room temperature without the need of solvents or triglycerides. Some of the flavor compounds are important building blocks of the hexagonal mesostructure, preventing phase transition with aging. The solubilization loads were relatively high: 12.6, 10.0, 12.6, and 10.0 wt % for phenylacetaldehyde, 2,6-dimethyl-5-heptenal, linalool, and trans-4-decenal, respectively. Phenylacetaldehyde formed mixtures of lamellar and cubic phases. Linalool, 2,6-dimethyl-5-heptenal, and trans-4-decenal induced structural shift from lamellar directly to H(II) mesophase, remaining stable at room temperature. Lattice parameters were found to increase with water content and to decrease with temperature and/or food volatile content. trans-4-Decenal produces more stable H(II) mesophase compared to linalool-loaded mesophase. At 40-60 °C, depending on the chemical structure and on the solubilization location of the food volatile compounds, the H(II) mesophase transforms to isotropic micellar phase, facilitating the release of the food volatile compounds. Molecular interactions suggest the existence of two consecutive stages in the solubilization process.

  2. Nebular Spectroscopy: A Guide on Hii Regions and Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Peimbert, Manuel; Peimbert, Antonio; Delgado-Inglada, Gloria

    2017-08-01

    We present a tutorial on the determination of the physical conditions and chemical abundances in gaseous nebulae. We also include a brief review of recent results on the study of gaseous nebulae, their relevance for the study of stellar evolution, galactic chemical evolution, and the evolution of the universe. One of the most important problems in abundance determinations is the existence of a discrepancy between the abundances determined with collisionally excited lines and those determined by recombination lines: this is called abundance discrepancy factor (ADF) problem, and we review results related to it. Finally, we discuss the possible reasons for the large t 2 values observed in gaseous nebulae.

  3. The sulfur doublet in galactic H-II regions

    NASA Technical Reports Server (NTRS)

    Mccracken, C. W.

    1973-01-01

    Spectrographic scans for sulfur doublet intensity in the Orion nebula show that electron density decreases from about 15,000 down to about 1500 electrons per cubic centimeter within a few minutes of arc in both directions from the maximum. There appears to be small-scale structure in the electron density, with variations by a factor of two very common. Satisfactory agreement is obtained for electron density values derived from the oxygen doublet as well as from the sulfur doublet.

  4. Do HI Companions to HII Galaxies Have Optical Counterparts?

    NASA Astrophysics Data System (ADS)

    Taylor, C. L.; Skillman, E. D.; Brinks, E.

    1994-05-01

    Taylor, Brinks & Skillman (1993; AJ 105, 128 and 1994; BAAS 25, 1342) mapped thirty dwarf galaxies undergoing bursts of star formation (HII galaxies) in the 21--cm line with the VLA. They discovered an HI rich companion population in the vicinity of these otherwise isolated galaxies. Of the thirty HII galaxies observed, eighteen have a total of twenty-two confirmed companions and two more have unconfirmed candidate companions. Ten had no companions within the primary beam of the VLA (30(') ) and inside the velocity range covered (+/- 250 km/s of each galaxy). The high detection rate of companions near HII galaxies suggests that interactions may have a role in instigating their bursts of star formation. Seven of the companions have high surface brightness optical counterparts, easily seen in the POSS. A further three were detected in preliminary R band CCD follow--up observations, leaving eight undetected down to a limiting surface brightness of 23 magnitudes per square arcsecond. We will present new observations of these fields, which will push our limiting surface brightness down to 26 magnitudes per square arcsecond, in an effort to determine whether or not these objects are truly intergalactic HI clouds, or are extremely low surface brightness dwarf galaxies. If it can be shown that the companions have have no stars then the study of these galaxy--massed HI clouds will yield constraints on what conditions are necessary for star formation to take place.

  5. Thermally induced fluid reversed hexagonal (H(II)) mesophase.

    PubMed

    Amar-Yuli, Idit; Wachtel, Ellen; Shalev, Deborah E; Moshe, Hagai; Aserin, Abraham; Garti, Nissim

    2007-12-06

    In the present study we characterized the microstructures of the Lc and HII phases in a glycerol monooleate (GMO)/tricaprylin (TAG)/water mixture as a function of temperature. We studied the factors that govern the formation of a low-viscosity HII phase at relatively elevated temperatures (>35 degrees C). This phase has very valuable physical characteristics and properties. The techniques used were differential scanning calorimetry (DSC), wide- and small-angle X-ray scattering (WAXS and SAXS, respectively), NMR (self-diffusion and (2)H NMR), and Fourier transform infrared (FTIR) spectroscopies. The reverse hexagonal phase exhibited relatively rapid flow of water in the inner channels within the densely packed cylindrical aggregates of GMO with TAG molecules located in the interstices. The existence of two water diffusion peaks reflects the existence of both mobile water and hydration water at the GMO-water interface (hydrogen exchange between the GMO hydroxyls and water molecules). Above 35 degrees C, the sample became fluid yet hexagonal symmetry was maintained. The fluidity of the HII phase is explained by a significant reduction in the domain size and also perhaps cylinder length. This phenomenon was characterized by higher mobility of the GMO, lower mobility of the water, and a significant dehydration process.

  6. Exoplanet Photometry and Spectroscopy with HII/L2

    NASA Astrophysics Data System (ADS)

    Tamura, M.

    2000-12-01

    With the recent discovery of extrasolar planets (exoplanets) around nearby stars by indirect methods, one of the next goals of the exoplanet study is to directly detect the giant exoplanets and to make photometry and spectroscopy. The next decade will be the time to move from discovery to characterization of exoplanet systems. This, however, requires all of high sensitivity, high spatial resolution, and high dynamic range observations at infrared wavelengths, which will be difficult to achieve from the ground. In this paper, we describe a coronagraphic camera and spectrometer for the HII/L2 mission for mid- and far-infrared astronomy and show the photometry and spectroscopy of exoplanets to be one of the most important scientific aims for this mission. The proposed HII/L2 coronagraph will cover the wavelength between 4 and 27 micron, optimized at 5 micron. The plate scale is about 0.06 arcsec, covering a field-of-view of about 1 arcmin by 1 arcmin with a 1024x1024 array detector. Occulting masks of diameter greater than 0.72 arcsec will be available, which enables the observations of exoplanets beyond ~2 AU around nearby (d~5 pc) stars. The coronagraph greatly takes advantage of the single (non-segmented) mirror of the HII/L2 telescope design. A high-efficiency Ge or CdTe grism with a resolution of a few hundreds will be installed for the coronagraphic spectroscopy of the exoplanet atmosphere. Rich spectral features at mid-infrared wavelengths enable us to study various atmospheric components and to make a comparative study of the exoplanets and our solar system planets.

  7. Aerodynamic study of H-II Orbiting Plane, HOPE

    NASA Astrophysics Data System (ADS)

    Akimoto, Toshio; Ito, Tetsuichi; Suzuki, Norio; Hozumi, Kokuichi; Sakakibara, Seizou; Kawamoto, Iwao

    NASDA's HOPE will be launched by an H-II vehicle and inserted into 250-km altitude orbit; after four days in orbit either conducting experiments or Space Station rendezvous and docking missions, HOPE will deorbit and automatically land on a runway. An account is given of the results of a study of the aerodynamics of the HOPE vehicle which was conducted in cooperation with Japan's NAL. Wind tunnel test results show that the double-delta planform must have long wingtip fins in order to possess positive static directional stability at low speed, as well as the requisite viscous-interaction parameter effects at hypersonic speeds and better aerodynamic heating distribution.

  8. Doppler Imaging of Two Zero-Age Main-Sequence Stars in the Pleiades: HII 686 and HII 3163

    NASA Astrophysics Data System (ADS)

    Stout-Batalha, N. M.; Vogt, S. S.

    1999-07-01

    Maximum entropy image reconstruction (Doppler imaging) is applied to HII 686 (K4 V, vsini=64 km s-1) and HII 3163 (K0 V, vsini=70 km s-1), two zero-age main-sequence stars of the Pleiades cluster. Their surface temperature distributions are determined in order to study the nature of magnetic activity in ultrafast rotators of known evolutionary status. Specific intensity line profiles used in the Doppler imaging (DI) algorithm are synthesized. The sensitivity of the reconstructions to the choice of input stellar and atomic data is investigated. The quality of the fit to the average disk-integrated line profile is found to be more important to DI analysis than the exact parameters used to generate the fit when the shape of the disk-integrated line profile is dominated by rotational broadening. Fifteen absorption lines are used to generate 15 individual reconstructions of each Pleiades target. Averaging reduces noise in the reconstructions. However, simulations reveal that spurious features tend to cluster systematically at subobserver longitudes and can therefore persist in the images even after averaging several reconstruction together. Such ``phase-ghosting'' becomes more severe as the signal-to-noise ratio decreases and does not appear to depend on the spot morphology. HII 686 shows one predominant feature at 77° latitude, which is 860 K cooler than the surrounding photosphere. HII 3163 shows a predominant feature centered at approximately 70° latitude, which has two temperature minima (780 K cooler than the photosphere) separated by approximately 130° in longitude. However, photometric observations suggest that this double-lobed morphology is a consequence of poor phase sampling. One temperature minimum located midway in longitude better reproduces the observed light curve. We are unable to make any reliable detections of low-latitude features on the surface of either star. The results are discussed in light of recent theoretical observations and existing

  9. Observações em Radiofreqüências do complexo de Regiões HII Compactas RCW 95

    NASA Astrophysics Data System (ADS)

    Barres de Almeida, Ulisses

    2006-05-01

    In this work we studied the complex of compact HII (CHII) regions RCW 95. The cloud is about 10'x10' and was mapped on the radio continuum emission at 43 GHz; a survey of water lines was also conducted at 22.2 GHz, corresponding to the 616 - 523 rotational transition of this molecule. The observations were made with the 14-meter single-dish antennae of the Itaptinga radio observatory, in Atibaia, ruled by INPE (Nacional Institute for Space Research, Brazil). For the continuum observations we made several scans in right ascension throughout the whole of the source spaced by 1' in declination, that were following combined to produce a map of isotemperatures for the cloud. The study resulted on the identification of resolved radio continuum sources associated with all the three IRAS sources in the region: IRAS 15408-5356, 15411-5352 and 15412-5359, all with far-IR colours characteristics of CHII regions. The water line survey resulted on the positive identification of maser emission associated with the three IRAS sources, supporting the evidences for these regions to harbour massive young stars. Two other unresolved HII regions, unassociated with far-IR sources, were also discovered through detailed analyses of the profiles of the radio continuum scans. The regions associated to the IRAS sources 15408-5356 and 15411-5352 were already known to be regions of massive star formation, whilst the stellar population associated to IRAS 15412-5359 had not been studied before. The discovery of water lines and the presence of a thermal continuum source on this direction suggested that this region could also contain young stars. We then conducted a study of the stellar population inside a region of 2'2' around this IRAS source using near-IR (J, H and K) band images from 2MASS catalogue. Throught this we were able to identify a significant population of massive stars, including one O9V star and some early BV that were charged responsibility for the ionization of the gas in the

  10. Sodium diclofenac and cell-penetrating peptides embedded in H(II) mesophases: physical characterization and delivery.

    PubMed

    Cohen-Avrahami, Marganit; Libster, Dima; Aserin, Abraham; Garti, Nissim

    2011-09-01

    Glycerol monooleate (GMO)-based mesophases offer extensive prospects for incorporation of various bioactive molecules. This work deals with the solubilization of selected cell-penetrating peptides (CPPs) together with sodium diclofenac (Na-DFC) within the H(II) mesophase for transdermal applications. The effect of CPPs such as RALA (an amphipatic CPP), penetratin (PEN), and oligoarginine (NONA) on Na-DFC skin permeation kinetics to provide controlled release and tune the drug transdermal diffusion was studied. The location of the drug and the CPPs within the mesophase was probed by DSC and FTIR. Na-DFC was found to be located at the interfacial region between the surfactant chains, leading to denser H(II) mesophase. The hydrophilic NONA was intercalated into the aqueous cylinders and caused their swelling. It induced a significant decrease in the hydrogen binding between the GMO carbonyls and their surrounding. The amphiphilic PEN was entrapped within two different regions, depending on its concentration. PEN and NONA improved Na-DFC permeation by 100%, whereas RALA enhanced permeation by 50%. When estimating Na-DFC migration rate out of the mesophase toward surrounding aqueous media, it appeared to be slower with the CPPs. The peptides were not involved at this diffusion-controlled step. It seems that their effect on skin permeation is based on their specific interaction with the skin.

  11. The pH-dependence of the Escherichia coli RNase HII-catalysed reaction suggests that an active site carboxylate group participates directly in catalysis.

    PubMed

    Bastock, James A; Webb, Michelle; Grasby, Jane A

    2007-04-27

    RNase HII specifically catalyses the hydrolysis of phosphate diester linkages contained within the RNA portion of DNA/RNA hybrids. The catalytic parameters of the enzyme derived from Escherichia coli BL21 have been measured using 5'-fluorescent oligodeoxynucleotide substrates containing embedded ribonucleotides. The products of the reaction and the chemistry of phosphate diester hydrolysis were assigned unequivocally using mass spectrometry. The pH-dependence of the catalytic parameters was measured under conditions of optimal magnesium ion concentration. The logarithm of the turnover number of the enzyme increases steeply with pH until a pH-independent region is reached close to neutrality. The slope of the pH-dependent region is 2, indicating that the catalytically proficient form of RNase HII is di-anionic. The pH-dependence of log 1/K(M) is a sigmoidal curve reaching a maximal value at higher pH, suggesting deprotonation of a residue stabilises substrate binding. Possible mechanisms for the RNase HII-catalysed reaction consistent with the pH-dependent behaviour of the enzyme are discussed. The active sites of RNase H enzymes contain a cluster of four strictly conserved carboxylate groups. Together, the data suggest a requirement for ionisation of an active site carboxylic acid for metal ion binding or correct positioning of metal ion(s) in the enzyme-substrate complex and a role for a second active site carboxylate in general base catalysis.

  12. H-II - A new launch vehicle in the 1990's

    NASA Astrophysics Data System (ADS)

    Godai, T.

    1985-10-01

    The H-II rocket is being planned by NASDA to carry a two-ton satellite into GEO. This paper summarizes the requirements, current status of design and tests, development program, and growth potential of the H-II. Also included are discussions of the mission, the configuration tradeoff study, system and subsystem descriptions, trajectory and performance analysis, test and launching facilities, and the development schedule.

  13. HII mesophase as a drug delivery system for topical application of methyl salicylate.

    PubMed

    Liang, Xin; Chen, Yu-Lin; Jiang, Xiao-Jing; Wang, Sheng-Mei; Zhang, Ji-Wen; Gui, Shuang-Ying

    2017-03-30

    The main objective of this study was to develop reversed hexagonal (HII) mesophase for transdermal delivery of methyl salicylate. The formulation was prepared, characterized and evaluated for its skin penetration in vitro and skin retention in vivo. Preliminary pharmacodynamics and skin irritation were also investigated. The formulation was identified as hexagonal structure. In vitro study exhibited that HII mesophase enhanced the skin permeation by delivering 2.61 times more methyl salicylate than the commercially available cream. Meanwhile, HII mesophase presented higher bioavailability as AUC(0-24) and AUC(0-∞) were 32.894μg·mL(-1) and 32.935μg·mL(-1) respectively, while the cream were 12.791μg·mL(-1) and 12.970μg·mL(-1). Preliminary pharmacodynamics studies demonstrated that HII mesophase possessed anti-inflammatory and analgesic effects for inhibiting paw edema, granuloma and pain. MeSa HII mesophase showed no skin irritation on the normal rat skin. Thus, HII mesophase was considered as an effective delivery system for MeSa.

  14. Feasibility Study of Electrodynamic Tether Technology Demonstration on H-II Transfer Vehicle

    NASA Astrophysics Data System (ADS)

    Kasai, Toru; Tsuijita, Daisuke; Uchiyama, Takashi; Harada, Masayuki; Kawamoto, Satomi; Ohkawa, Yasushi; Inoue, Koichi

    2013-09-01

    Space debris has been steadily increasing. Cascading effect caused by the collision between the objects would worsen the situation further. To ensure the safety of future space activities, aggressive measures to reduce debris is needed. Since density of debris in the region of 800 km to 1500 km altitude is particularly high, the occurrence of cascade event can be a major obstacle for activities in Low Earth Orbit (LEO). To avoid this situation, JAXA is investigating a service system to capture a defunct satellite and remove it from this "crowded" orbit to waste orbit. Conventional propulsion system, which requires much propellant, is inefficient for this application. JAXA has been investigating to use of ElectroDynamic Tether (EDT) propulsion system. By using the interaction with the Earth magnetic field, EDT can generate a sufficient thrust for orbit transfer over a realistic time period. JAXA is now investigating to demonstrate EDT technology on-orbit and H-II Transfer Vehicle (HTV), JAXA's unmanned cargo transfer spacecraft to the International Space Station (ISS), is a potential candidate of hosted vehicle. This paper will present HTV's active deorbit design in first, and also present result of feasibility study of JAXA's first attempt of EDT on-orbit demonstration on the HTV.

  15. Statistics and properties of H II regions in a sample of grand-design galaxies. II. Physical properties.

    NASA Astrophysics Data System (ADS)

    Rozas, M.; Knapen, J. H.; Beckman, J. E.

    1996-08-01

    We describe statistical properties of complete samples of HII regions in the grand-design spiral galaxies NGC 157, NGC 3631, NGC 6764 and NGC 6951. We use the catalogues of HII regions obtained from high-quality Hα line images by Rozas et al. . Slopes and zero points of diameter distribution functions for these four galaxies coincide well with values published for other galaxies of similar morphological type. We also present density distributions and Hα scale lengths, as well as luminosity-volume and number-luminosity-size relations. The latter relations show evidence for the presence of a population of high luminosity density-bounded HII regions in the spiral arms. We see the change from ionization- to density-bounded HII regions occur clearly at a specific HII region flux level.

  16. The Green Bank Telescope Galactic H II Region Discovery Survey

    NASA Astrophysics Data System (ADS)

    Bania, Thomas M.; Anderson, L. D.; Balser, D. S.; Rood, R. T.

    2010-05-01

    We discovered a large population of previously unknown Galactic HII regions by using the NRAO Green Bank Telescope to detect hydrogen radio recombination line (RRL) emission from these nebulae. Since recombination lines are optically thin at 3 cm wavelength, we can detect HII regions across the entire Galactic disk. Our targets were selected based on spatially coincident 24µm (Spitzer/MIPSGAL) and 21 cm (either from the VLA Galactic Plane Survey or the NRAO NVSS) continuum emission. For the Galactic zone, -16° < Lgal < 67° and |Bgal|<1°, we detected 602 discrete RRL components from 95% of the sample targets, which more than doubles the number of known HII regions in this part of the Milky Way. We found 25 new first quadrant nebulae with negative RRL velocities, placing them beyond the Solar orbit in the Perseus arm. We plan to determine the distance to over 90% of our sources (for the region Lgal>18°) by using HI emission/absorption experiments to resolve the kinematic distance ambiguity. Because we can detect all nebulae inside the Solar orbit that are ionized by O-stars, the Discovery Survey targets, when combined with existing HII region catalogs, will give a more accurate census of Galactic HII regions and their properties. The distribution of HII regions across the Galactic disk shows strong, narrow ( 1 kpc wide) peaks at Galactic radii of 4.3 and 6.0 kpc. There is still an overall dearth of HII regions within 4 kpc radius. For the first time the longitude-velocity distribution of HII regions gives unambiguous evidence for Galactic structure, including the kinematic signatures of the radial peaks in the spatial distribution, a concentration of nebulae at the end of the Galactic Bar, and nebulae located in kinematic locus of the 3 kpc Arm.

  17. Results from the Heavy Ions In Space (HIIS) experiment on the ionic charge state of solar energetic particles

    NASA Technical Reports Server (NTRS)

    Tylka, Allan J.; Boberg, Paul R.; Adams, James H., Jr.; Beahm, Lorraine P.; Kleis, Thomas

    1995-01-01

    It has long been known that low-energy solar energetic particles (SEP's) are partially-ionized. For example, in large, so-called 'gradual' solar energetic particle events, at approximately 1 MeV/nucleon the measured mean ionic charge state, Q, of Fe ions is 14.1 +/- 0.2, corresponding to a plasma temperature of approximately 2 MK in the coronal or solar-wind source material. Recent studies, which have greatly clarified the origin of solar energetic particles and their relation to solar flares, suggest that ions in these SEP events are accelerated not at a flare site, but by shocks propagating through relatively low-density regions in the interplanetary medium. As a result, the partially-ionized states observed at low energies are expected to continue to higher energies. However, up to now there have been no high-energy measurements of ionic charge states to confirm this notion. We report here HIIS observations of Fe-group ions at 50-600 MeV/nucleon, at energies and fluences which cannot be explained by fully-ionized galactic cosmic rays, even in the presence of severe geomagnetic cutoff suppression. Above approximately 200 MeV/nucleon, all features of our data -- fluence, energy spectrum, elemental composition, and arrival directions -- can be explained by the large SEP events of October 1989, provided that the mean ionic charge state at these high energies is comparable to the measured value at approximately 1 MeV/nucleon. By comparing the HIIS observations with measurements in interplanetary space in October 1989, we determine the mean ionic charge state of SEP Fe ions at approximately 200-600 MeV/nucleon to be Q = 13.4 plus or minus 1.0, in good agreement with the observed value at approximately 1 MeV/nucleon. The source of the ions below approximately 200 MeV/nucleon is not yet clear. Partially-ionized ions are less effectively deflected by the Earth's magnetic field than fully-ionized cosmic rays and therefore have greatly enhanced access to low-Earth orbit

  18. Preliminary battleship tank firing test of H-II launch vehicle first stage

    NASA Astrophysics Data System (ADS)

    Mori, Masahiro; Kazama, Hiroo; Nakatsuji, Hiroyuki; Yamazaki, Isao; Maemura, Takashi; Atsumi, Masahiro

    The development, objectives, facilities, and results of a preliminary battleship tank firing test series of the first stage propulsion system of the H-II rocket are discussed. The test series included two engine chilldown tests and 12 short-duration hot firing tests. The results verify the basic compatibility of the tank system and the LE-7 engine.

  19. M.(phi)BssHII, a novel cytosine-C5-DNA-methyltransferase with target-recognizing domains at separated locations of the enzyme.

    PubMed Central

    Sethmann, S; Ceglowski, P; Willert, J; Iwanicka-Nowicka, R; Trautner, T A; Walter, J

    1999-01-01

    In all cytosine-C5-DNA-methyltransferases (MTases) from prokaryotes and eukaryotes, remarkably conserved amino acid sequence elements responsible for general enzymatic functions are arranged in the same canonical order. In addition, one variable region, which includes the target-recognizing domain(s) (TRDs) characteristic for each enzyme, has been localized in one region between the same blocks of these conserved elements. This conservation in the order of conserved and variable sequences suggests stringent structural constraints in the primary structure to obtain the correct folding of the enzymes. Here we report the characterization of a new type of a multispecific MTase, M.(phiphi)BssHII, which is expressed as two isoforms. Isoform I is an entirely novel type of MTase which has, in addition to the TRDs at the conventional location, one TRD located at a non-canonical position at its N-terminus. Isoform II is represented by the same MTase, but without the N-terminal TRD. The N-terminal TRD provides HaeII methylation specificity to isoform I. The TRD is fully functional when engineered into either the conventional variable region of M.(phiphi)BssHII or the related monospecific M.phi3TII MTase. The implications of this structural plasticity with respect to the evolution of MTases are discussed. PMID:10369689

  20. Análise da cinemática interna das regiões HII gigantes e das galáxias HII

    NASA Astrophysics Data System (ADS)

    Plana, H.; Telles, E.; Maíz-Apellániz, J.

    2003-08-01

    Neste trabalho nós mostramos os primeiros resultados de um estudo sobre a cinemática das Regiões HII Gigantes (GHIIRs) em galáxias próximas. Essas regiões HII têm um diâmetro médio entre 100 pc e 1000 pc e uma taxa de formação estelar de 106 M¤ / ano sendo equivalente à observada em galáxias de tipo tardio correspondendo a uma taxa de formação estelar por unidade de volume uma ordem de magnitude maior que a observada em regiões HII normais. Usando espectros de fenda longas em várias posições, nós construímos mapas de velocidades, de dispersão e de intensidade para várias linhas de emissão como Ha, Hb, [NII]6584 Å, [OIII]5007 Å e o doublet de [SII], para cinco regiões gigantes: NGC 2403 II e IV, NGC 595, NGC 5461, NGC 5471, NGC 5455. O estudo da cinemática (mapas de velocidades e da dispersão) mostrou, por exemplo, a presença de cascas em expansão em NGC 595 ou perfis de emissão com várias componentes em NGC 5461. Os perfis de emissão também mostram velocidades supersônicas. Os resultados são discutidos em comparação com os de estudos anteriores realizados.

  1. Condições físicas em galáxias HII

    NASA Astrophysics Data System (ADS)

    Kehrig, C.; Telles, E.; Cuisinier, F.

    2003-08-01

    Galáxias HII são galáxias anãs de baixa luminosidade que apresentam alta taxa de formação estelar. Seus espectros são dominados por intensas linhas de emissão devido à fotoionização pela presença de um grande número de estrelas do tipo O e B. Nós apresentamos um catálogo espectrofotométrico de 111 galáxias HII observadas no telescópio 1.52m do ESO com o espectrógrafo Boller & Chivens. Determinamos propriedades estatísticas da amostra e derivamos condições físicas (temperatura eletrônica, densidade eletrônica) e abundâncias químicas. Para algumas galáxias, fomos também capazes de resolver espacialmente regiões de formação estelar individuais e determinar propriedades espectroscópicas para estas regiões separadamente, o que nos permitiu avaliar as flutuações das condições físico-químicas dentro das galáxias HII. Em particular, vimos que apesar das galáxias HII apresentarem formação estelar espalhada ao longo do corpo da galáxia, são objetos quimicamente homogêneos. A fim de estudar a evolução temporal dos objetos durante o tempo de vida das estrelas ionizantes construimos também alguns diagramas relacionando razões de linhas de emissão com a largura equivalente de Hb (EW(Hb)). Para interpretar tais diagramas utilizamos modelos de fotoionização para populações estelares integradas. Concluímos que as galáxias HII não correspondem a simples idéia de um burst instantâneo envolvido por um gás opaco aos fótons ionizantes e com densidade constante. As relações observadas entre razões de linhas e EW(Hb) podem ser melhor compreendidas se as galáxias HII apresentarem populações estelares mais velhas, que contribuem para o contínuo óptico observado.

  2. The H-Impairment Index (HII): a standardized assessment of alcohol-induced impairment in the Emergency Department.

    PubMed

    Hack, Jason B; Goldlust, Eric J; Gibbs, Frantz; Zink, Brian

    2014-03-01

    Emergency Departments (EDs) care for thousands of alcohol-intoxicated patients annually. No clinically relevant bedside measures currently exist to describe degree of impairment. To assess a group of bedside tests ("Hack's Impairment Index [HII] score") that applies a numerical value to the degree of alcohol-induced impairment in ED patients. A six-month retrospective review of HII score data was performed in a convenience sample of 293 intoxicated ED patients. Patients were scored 0-4 on five tasks, divided by the maximum score (20 if all tasks completed), every 2 hours; and classified by the number of visits: Low-frequency (1 visit); Medium-frequency (2 visits); High-frequency (≥3 visits). Correlations were assessed between HII score, healthcare provider judgment of intoxication, and measured alcohol levels. Study patients had 513 visits; 236 were low-frequency, 26 middle-frequency and 31 high-frequency. Clinical assessment and HII score were strongly correlated (Spearman's rho = 0.82, p < 0.001); clinical assessment and alcohol level less strongly so (rho = 0.49, p < 0.001). Among low-frequency patients, HII score and alcohol level were weakly correlated (r = 0.324, p < 0.001), with no such correlation among high-frequency visitors (r = -0.04, p = 0.89). The mean decline between serial HII scores was 0.126 (95% CI: 0.098-0.154). This pilot study shows the HII score can be performed at the bedside of alcohol-intoxicated patients. The HII declines in a reasonably predictable manner over time; and applies a quantitative, objective assessment of alcohol impairment.

  3. Conceptual study of manned space transportation vehicle using laser thruster in combination with the H-II rocket

    NASA Astrophysics Data System (ADS)

    Minami, Yoshinari; Uchida, Shigeaki

    2013-02-01

    This paper describes the conceptual study of a Manned Space Transportation Vehicle (MSTV) using a laser thruster in combination with the H-II Rocket. By combining the use of a laser thruster and H-II Rocket, space trip to the International Space Station (ISS) or a round trip mission around the moon can be performed. Once MSTV with one crew achieves a circular orbit at an altitude of 200 km around the earth (parking orbit) by use of H-II Rocket, MSTV will then put into a circular orbit into an altitude of 400 km (ISS orbit) from 200 km circular orbit by use of the laser thruster. H-II Rocket has the following launch capability with payloads for LEO (300 km): 10 t (H-II A Rocket), 16.5 t (H-II B Rocket). Laser thruster using water propellant, power source for the laser, orbital transfer calculations (to ISS or the Moon) and other practical aspects are examined.

  4. Battleship tank firing test of H-II launch vehicle second stage

    NASA Astrophysics Data System (ADS)

    Mori, Masahiro; Kazama, Hiroo; Nakatsuji, Hiroyuki; Yamazaki, Isao; Maekawa, Hiroshi; Nakagawa, Toshihiko

    The objectives, facilities, articles, and results are presented of a series of battleship tank firing tests on the second stage propulsion systems of the H-II launch vehicle. The test series included 11 hot firing tests under first burn conditions, restart conditions, and idle mode conditions. Oscillatory perturbations were added to the LOX flow in some cases to obtain data concerning POGO oscillation. The results verify the functions of the second stage propulsion system.

  5. VLT/NACO near-infrared imaging and spectroscopy of N159-5 in the LMC HII complex N159

    NASA Astrophysics Data System (ADS)

    Testor, G.; Lemaire, J. L.; Kristensen, L. E.; Field, D.; Diana, S.

    2007-07-01

    We present high-resolution near-infrared imaging of the compact HII region N159-5 and its immediate environment in the giant-star forming region N159 in the LMC. N159-5 was observed at high spatial resolution 0.11-0.25 arcsec in the K-band using the ESO Very Large Telescope UT4 (VLT), equipped with the NAOS adaptive optics system. Our data reveal that N159-5 has a complex morphology formed mainly by two wings and probably a single central bright star, embedded in diffuse emission of 4.5 arcsec diameter. A remarkable embedded tight cluster of approximatively the same size, containing at least 38 faint stars coinciding with N159-5, is also detected. Such clusters can be found in galactic HII regions like the star-forming regions SH2 269 or M42. At the location of the radio peak, especially in the bright western wing, this cluster is rich in stars. Spectroscopic observations reveal that the diffuse region is constituted mainly of dust continuum and that the bright star #2-55 could be of type O8 V. A comparison with the radio observation flux of N159-5 published in the literature seems to show that the bright star #2-55 is not the only ionization source of N159-5. Towards N159-5 molecular H{2} emission is detected. A model of the region is proposed. Based on observations obtained at the European Southern Observatories, El Paranal, Chile. Table [see full text] is only available in electronic form at http://www.aanda.org

  6. Estudo da região HII galática NGC 2579

    NASA Astrophysics Data System (ADS)

    Riffel, R.; Copetti, M. V. F.

    2003-08-01

    Desde a descoberta dos gradientes de abundância química em galáxias espirais, as regiões HII galáticas têm sido intensamente estudadas com o objetivo de determinar a forma do gradiente de abundância química na Via-Láctea. Entretanto, a forma do gradiente galático continua controversa e existem muitas regiões HII que continuam inexploradas. A região HII galática NGC 2579 é um objeto que aparece em imagens Ha, como uma pequena mancha brilhante de aproximadamente 2 segundos de arco de diâmetro a 20 segundos de arco ao leste de RCW 20, sendo NGC 2579 muitas vezes confundida com esta última. Apesar de seu alto brilho superficial, NGC 2579 é um objeto pouco estudado provavelmente por problemas de identificação deste objeto. Como parte de um projeto de reavaliação dos gradientes de abundância química das regiões HII na Via-Láctea, estamos realizando um estudo extensivo das propriedades físicas básicas como temperatura eletrônica, densidade eletrônica e composição química da região HII galática NGC 2579. Analisamos dados espectrofotométricos de fenda longa na faixa de 3700Å a 7750Å obtidos com o telescópio de 1.52 m do ESO, Chile, em 2002. Determinamos a temperatura eletrônica usando a razão entre as linhas do [OIII] (l4959+l5007/l4363) e a densidade eletrônica pela razão entre as linhas do [SII] (l6716/l6731). As abundâncias químicas do O, N, Cl, S, Ne e He foram determinadas. Realizamos um estudo de imagens fotométricas nas bandas UBVRI obtidas em 2000 no observatório astronômico San Pedro Mártir, México, para identificar e classificar as estrelas ionizantes de NGC 2579 e determinar a distância deste objeto.

  7. VizieR Online Data Catalog: Star forming regions sulphur ICFs (Dors+, 2016)

    NASA Astrophysics Data System (ADS)

    Dors, O. L.; Perez-Montero, E.; Hagele, G. F.; Cardaci, M. V.; Krabbe, A. C.

    2016-10-01

    We compiled from the literature emission-line intensities of HII regions and star-forming galaxies obtained in the optical and infrared spectral ranges. These measurements were used to obtain sulphur and oxygen ionic abundances in order to verify if our photoionization models are representative of real HIi regions, to check if the theoretical ICFs are compatible with the ones derived directly from observations and investigating the S/O-O/H relation. (5 data files).

  8. Chandra observations of the HII complex G5.89-0.39 and TeV gamma-ray source HESSJ1800-240B

    NASA Astrophysics Data System (ADS)

    Hampton, E. J.; Rowell, G.; Hofmann, W.; Horns, D.; Uchiyama, Y.; Wagner, S.

    2016-09-01

    We present the results of our investigation, using a Chandra X-ray observation, into the stellar population of the massive star formation region G5.89-0.39, and its potential connection to the coincident TeV gamma-ray source HESSJ1800-240B. G5.89-0.39 comprises two separate HII regions G5.89-0.39A and G5.89-0.39B (an ultra-compact HII region). We identified 159 individual X-ray point sources in our observation using the source detection algorithm wavdetect. 35 X-ray sources are associated with the HII complex G5.89-0.39. The 35 X-ray sources represent an average unabsorbed luminosity (0.3-10 keV) of ∼1030.5erg /s, typical of B7-B5 type stars. The potential ionising source of G5.89-0.39B known as Feldt's star is possibly identified in our observation with an unabsorbed X-ray luminosity suggestive of a B7-B5 star. The stacked energy spectra of these sources is well-fitted with a single thermal plasma APEC model with kT ∼ 5 keV, and column density NH = 2.6 ×1022cm-2 (AV ∼ 10). The residual (source-subtracted) X-ray emission towards G5.89-0.39A and B is about 30% and 25% larger than their respective stacked source luminosities. Assuming this residual emission is from unresolved stellar sources, the total B-type-equivalent stellar content in G5.89-0.39A and B would be 75 stars, consistent with an earlier estimate of the total stellar mass of hot stars in G5.89-0.39. We have also looked at the variability of the 35 X-ray sources in G5.89-0.39. Ten of these sources are flagged as being variable. Further studies are needed to determine the exact causes of the variability, however the variability could point towards pre-main sequence stars. Such a stellar population could provide sufficient kinetic energy to account for a part of the GeV to TeV gamma-ray emission in the source HESSJ1800-240B. However, future arc-minute angular resolution gamma-ray imaging will be needed to disentangle the potential gamma-ray components powered by G5.89-0.39 from those powered by the

  9. Battleship tank firing test of H-II launch vehicle - First stage

    NASA Astrophysics Data System (ADS)

    Watanabe, Atsutaro; Endo, Mamoru; Yamazaki, Isao; Maemura, Takashi; Namikawa, Tatsuo

    1991-06-01

    The H-II launch vehicle capable of placing 2-ton-class payloads on geostationary orbits is outlined, and focus is placed on its propulsion system. The development status of the project, including component development, preliminary battleship tank firing test (BFT-1), battleship tank firing test (BFT-2), and flight-type tank firing test (CFT) is discussed. The configuration and schematic diagram of BFT-2 are presented, and the firing test results of BFT-2 first series are analyzed, including engine performance, interface compatibility, and pressurization of subsystems.

  10. Molecular theory of lipid-protein interaction and the Lalpha-HII transition.

    PubMed Central

    May, S; Ben-Shaul, A

    1999-01-01

    We present a molecular-level theory for lipid-protein interaction and apply it to the study of lipid-mediated interactions between proteins and the protein-induced transition from the planar bilayer (Lalpha) to the inverse-hexagonal (HII) phase. The proteins are treated as rigid, membrane-spanning, hydrophobic inclusions of different size and shape, e.g., "cylinder-like," "barrel-like," or "vase-like." We assume strong hydrophobic coupling between the protein and its neighbor lipids. This means that, if necessary, the flexible lipid chains surrounding the protein will stretch, compress, and/or tilt to bridge the hydrophobic thickness mismatch between the protein and the unperturbed bilayer. The system free energy is expressed as an integral over local molecular contributions, the latter accounting for interheadgroup repulsion, hydrocarbon-water surface energy, and chain stretching-tilting effects. We show that the molecular interaction constants are intimately related to familiar elastic (continuum) characteristics of the membrane, such as the bending rigidity and spontaneous curvature, as well as to the less familiar tilt modulus. The equilibrium configuration of the membrane is determined by minimizing the free energy functional, subject to boundary conditions dictated by the size, shape, and spatial distribution of inclusions. A similar procedure is used to calculate the free energy and structure of peptide-free and peptide-rich hexagonal phases. Two degrees of freedom are involved in the variational minimization procedure: the local length and local tilt angle of the lipid chains. The inclusion of chain tilt is particularly important for studying noncylindrical (for instance, barrel-like) inclusions and analyzing the structure of the HII lipid phase; e.g., we find that chain tilt relaxation implies strong faceting of the lipid monolayers in the hexagonal phase. Consistent with experiment, we find that only short peptides (large negative mismatch) can induce the

  11. Low energy ions in the heavy ions in space (HIIS) experiment on LDEF.

    PubMed

    Kleis, T; Tylka, A J; Boberg, P R; Adams, J H; Beahm, L P

    1996-01-01

    We present data from the Lexan top stacks in the Heavy Ions In Space (HIIS) experiment which was flown for six years (April 1984-Jan 1990) onboard the LDEF spacecraft in 28.5 degrees orbit at about 476 km altitude. HIIS was built of passive (i.e. no timing resolution) plastic track detectors which collected particles continuously over the entire mission. In this paper we present data on low energy heavy ions (10 < or = Z, 20MeV/nuc < E < 200 MeV/nuc). These ions are far below the geomagnetic cutoff for fully ionized ions in the LDEF orbit even after taking into account the severe cutoff suppression caused by occasional large geomagnetic storms during the LDEF mission. Our preliminary results indicate an unusual elemental composition of trapped particles in the inner magnetosphere during the LDEF mission, including both trapped anomalous cosmic ray species (Ne, Ar) and other elements (such as Mg and Fe) which are not found in the anomalous component of cosmic rays. The origin of the non-anomalous species is not understood, but they may be associated with the solar energetic particle events and geomagnetic disturbances of 1989.

  12. Populações estelares em galáxias HII

    NASA Astrophysics Data System (ADS)

    Westera, P.; Cuisinier, F.; Telles, E.; Kehrig, C.

    2003-08-01

    Analisamos o conteúdo estelar de 74 galáxias HII a partir do contínuo observado nos espectros ópticos dessas galáxias, utilizando métodos de síntese de população estelar. Descobrimos que todas as galáxias para as quais encontramos soluções contêm uma população estelar velha que domina a massa estelar, e numa maioria dessas também encontramos evidência de uma população de idade intermediaria além da geração jovem que está se formando agora. Concluímos que a formação estelar dessas galáxias se realiza em surtos individuais, Esses surtos são interrompidos por longos períodos de inatividade, com os primeiros consumindo a maior parte do gás. Sugerimos, portanto, que as galáxias HII sejam galáxias anãs normais flagradas em um período de surto.

  13. VizieR Online Data Catalog: Ultra-compact HII regions & methanol masers. I. (Hu+, 2016)

    NASA Astrophysics Data System (ADS)

    Hu, B.; Menten, K. M.; Wu, Y.; Bartkiewicz, A.; Rygl, K.; Reid, M. J.; Urquhart, J. S.; Zheng, X.

    2017-03-01

    372 unique targets were selected from the following methanol maser surveys: the Methanol Multi-Beam catalog (MMB; Caswell & Breen 2010MNRAS.407.2599C; Green+ 2010-2012, VIII/96), the Arecibo Methanol Maser Galactic Plane Survey (AMGPS; Pandian+ 2011ApJ...730...55P), the Torun catalog of 6.7GHz methanol masers (Szymczak+ 2012, J/AN/333/634), and other individual observations of known 6.7GHz methanol masers or MSFRs (Caswell+ 1995MNRAS.272...96C; Walsh+ 1997, J/MNRAS/291/261; 1998, J/MNRAS/301/640; Xu+ 2008A&A...485..729X; Caswell 2009, J/other/PASA/26.454). The observations were conducted with the VLA in C-configuration using five sessions from 2012 February 28 to April 16. Spectral line data used 2048 channels across 8MHz, yielding a channel spacing of 3.90625kHz at the central frequency of 6.6685192GHz and a velocity resolution of 0.176km/s. The continuum observations employed two 1GHz sub-bands from 4.9840 to 6.0080GHz (the low band) and from 6.6245 to 7.6485GHz (the high band) and each sub-band was divided into 16 channels. (4 data files).

  14. VizieR Online Data Catalog: M33 HII regions SED (Relano+, 2013)

    NASA Astrophysics Data System (ADS)

    Relano, M.; Verley, S.; Perez, I.; Kramer, C.; Calzetti, D.; Xilouris, E. M.; Boquien, M.; Abreu-Vicente, J.; Combes, F.; Israel, F.; Tabatabaei, F. S.; Braine, J.; Buchbender, C.; Gonzalez, M.; Gratier, P.; Lord, S.; Mookerjea, B.; Quintana-Lacaci, G.; van der Werf, P.

    2013-09-01

    To investigate the continuum UV emission of M 33, we used the data from GALEX, in particular the data distributed by de Paz et al. (2007, Cat. J/ApJS/173/185). To trace the ionised gas, we used the narrow-line Hα image of M 33 obtained by Greenawalt (1998, Ph.D. Thesis, New Mexico state University). Dust emission can be investigated through the mid-IR (MIR) and FIR data of M 33 obtained with the Spitzer Infrared Array Camera (IRAC) and Multiband Imaging Photometer (MIPS). (3 data files).

  15. VizieR Online Data Catalog: Galactic MCs associated with HII regions (Vutisalchavakul+, 2016)

    NASA Astrophysics Data System (ADS)

    Vutisalchavakul, N.; Evans, N. J., II; Heyer, M.

    2017-01-01

    In this paper, we collect data from surveys of radio recombination lines (RRLs), radio continuum emission, and MIR emission to measure SFR, from 13CO spectroscopy to evaluate molecular cloud (MC) properties, and from millimeter dust continuum emission to trace the dense gas component. See section 2 for the data sources. (4 data files).

  16. VizieR Online Data Catalog: MWA Survey of Galactic HII regions (Hindson+, 2016)

    NASA Astrophysics Data System (ADS)

    Hindson, L.; Johnston-Hollitt, M.; Hurley-Walker, N.; Callingham, J. R.; Su, H.; Morgan, J.; Bell, M.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Deshpande, A. A.; Dwarakanath, K. S.; For, B.-Q.; Gaensler, B. M.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Kapin, A. D.; Kaplan, D. L.; Lenc, E.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Offringa, A.; Ord, S. M.; Procopio, P.; Prabu, T.; Udaya Shankar, N.; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.; Wu, C.; Zheng, Q.

    2016-06-01

    We use observations that utilise the MWA interferometer, which is the low frequency precursor for the Square Kilometre Array (SKA), located at the Murchison Radio-astronomy Observatory in Western Australia. The observations presented in this study were obtained as part of the GLEAM survey (Wayth et al., 2015PASA...32...25W). (1 data file).

  17. VizieR Online Data Catalog: Interstellar reddening in 3 HII regions (Straizys+, 2008)

    NASA Astrophysics Data System (ADS)

    Straizys, V.; Corbally, C. J.; Laugalys, V.

    2008-11-01

    The slope of the interstellar reddening line in the J-H vs. H-Ks diagram of the 2MASS survey in the direction of the North America and Pelican nebulae, the L 935 dust cloud and the Cyg OB2 association is determined. The MK types were either classified by C.J. Corbally or collected from the literature. The ratio E(J-H)/E(H-Ks)=2.0 is obtained by taking the average for the four groups of spectral classes: O3-B1, B2-B6, B7-B9.5 and red clump giants. The obtained ratio is among the largest values of E(J-H)/E(H-Ks) determined till now. (2 data files).

  18. VizieR Online Data Catalog: The HII Region Discovery Survey (HRDS). II. (Anderson+, 2011)

    NASA Astrophysics Data System (ADS)

    Anderson, L. D.; Bania, T. M.; Balser, D. S.; Rood, R. T.

    2011-08-01

    Our observations were made with the Green Bank Telescope (GBT) 100m telescope from 2008 June through 2010 October. We assembled our target list from the following multi-frequency, large solid angle Galactic surveys: the NRAO Very Large Array (VLA) Galactic Plane Survey at 21cm HI and continuum (VGPS: Stil et al. 2006AJ....132.1158S), the NRAO VLA Sky Survey at 20cm continuum (NVSS: Condon et al. 1998, Cat. VIII/65), the Southern Galactic Plane Survey at 21cm HI and continuum (SGPS: Haverkorn et al. 2006ApJS..167..230H), the VLA MAGPIS at 20cm continuum (Helfand et al. 2006, Cat. J/AJ/131/2525), and the Spitzer 24um MIPSGAL survey (Carey et al. 2009PASP..121...76C). Our analysis here also uses 8.0um data from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE: Benjamin et al. 2003PASP..115..953B), which were obtained with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. (4 data files).

  19. Spatial and temporal variations of reddening parameters toward HII regions in the Milky Way galaxy

    NASA Astrophysics Data System (ADS)

    Vargas Alvarez, Carlos A.

    The purpose of this thesis is to determine if the value of the total-to-selective extinction ratio, RV, has spatial and temporal variations as dust is modified by UV photons. Historically this value has been assumed to be 3.1 after averaging the values along different sightlines in the Milky Way Galaxy. This work will also demonstrate, that for areas of recent star formation with heavy extinction a proper study can not be done when assuming the nominal value, but a local value of RV must first be determined. For this purpose I will analyze the reddening parameters RV and A V toward the massive cluster Westerlund 2 and several mid-IR bubbles located in the G38.91-0.42 complex. Three reddening laws that made different assumptions about RV are applied to the spectral energy distribution (SED) of the observed stars. These SEDs are compared to the available optical and IR photometry searching for the RV and AV that minimizes the chi 2 of the fit.

  20. VizieR Online Data Catalog: Long slit spectroscopy of HII regions (Marquez+, 2004)

    NASA Astrophysics Data System (ADS)

    Davoust, E.; Contini, T.

    2004-03-01

    The observations were obtained at the large decimetric radiotelescope of Nancay Observatory. Three runs (a total of 281h) were allocated for the barred subsample in 1993-94, and six runs (214h) for the unbarred subsample in 1996-99. We observed a total of 111 galaxies, and detected 80 (+ one companion), of which 64 are new detections. (3 data files).

  1. VizieR Online Data Catalog: HII region abundances in NGC 5457 (M101) (Croxall+, 2016)

    NASA Astrophysics Data System (ADS)

    Croxall, K. V.; Pogge, R. W.; Berg, D. A.; Skillman, E. D.; Moustakas, J.

    2017-01-01

    Optical spectra of NGC 5457 were taken using Multi-Object Double Spectrographs (MODS) on the Large Binocular Telescope (LBT) during the spring semester of 2015. We obtained simultaneous blue and red spectra using the G400L (R~1850) and G670L (R~2300) gratings, respectively. This setup provided broad spectral coverage extending from 3200 to 10000Å. (3 data files).

  2. The effect of bilayer and hexagonal H(II) phase lipid films on transepidermal water loss.

    PubMed

    Raney, Sameersingh G; Hope, Michael J

    2006-07-01

    The common membrane phospholipids tend to adopt either the familiar bilayer phase or the less familiar hexagonal H(II) phase when isolated and hydrated in excess water. The objective of this study was to compare the effects of these very different macroscopic lipid structures on transepidermal water loss (TEWL) when they are applied to the surface of pig skin mounted in Franz diffusion cells. First, a novel in vitro method for monitoring TEWL was developed and characterized in which the flux of water from the subphase through skin was measured through the absorption of (3H)-water by lyophilized polyethylene glycol (PEG) mounted above the skin surface. TEWL was varied by disrupting the skin barrier to different degrees by tape stripping or solvent extraction. Bilayer-forming egg phosphatidylcholine (EPC) or hexagonal H(II)-forming dioleoyl phosphatidylethanolamine (DOPE) were applied topically as solutions in ethanol and subsequently dried to films. The molecular configuration adopted by each lipid at the skin surface was confirmed by phosphorus NMR. TEWL for normal skin was approximately 2 g H2O/h/m2, increasing to a maximum of 80 g H2O/h/m2 after the stratum corneum was completely removed by tape stripping. On tape-stripped skin, films of lipid doses as low as 10 mg/cm2 significantly reduced TEWL, and DOPE (hexagonal H(II)) was approximately twofold more effective than EPC (bilayer). Furthermore, the effects of EPC and Vaseline on reducing TEWL from damaged skin were readily reversed by a simple aqueous wash, whereas the DOPE effect was unaltered even by vigorous washing. Similar results were obtained with lipid films applied to solvent-extracted skin. The data are consistent with the formation of extensive hydrophobic interactions between the skin and the outwardly facing acyl chains of the inverted, hexagonal H(II) phase adopted by DOPE. This results in the formation of a durable surface barrier capable of significantly reducing TEWL from damaged skin.

  3. Quasar H II Regions During Cosmic Reionization

    SciTech Connect

    Alvarez, Marcelo A.; Abel, Tom; /KIPAC, Menlo Park

    2007-03-30

    Cosmic reionization progresses as HII regions form around sources of ionizing radiation. Their average size grows continuously until they percolate and complete reionization. We demonstrate how this typical growth can be calculated around the largest, biased sources of UV emission such as quasars by further developing an analytical model based on the excursion set formalism. This approach allows us to calculate the sizes and growth of the HII regions created by the progenitors of any dark matter halo of given mass and redshift with a minimum of free parameters. Statistical variations in the size of these pre-existing HII regions are an additional source of uncertainty in the determination of very high redshift quasar properties from their observed HII region sizes. We use this model to demonstrate that the transmission gaps seen in very high redshift quasars can be understood from the radiation of only their progenitors and associated clustered small galaxies. The fit requires the epoch of overlap to be at z = 5.8 {+-} 0.1. This interpretation makes the transmission gaps independent of the age of the quasars observed. If this interpretation were correct it would raise the prospects of using radio interferometers currently under construction to detect the epoch of reionization.

  4. Spotted star light curve numerical modeling technique and its application to HII 1883 surface imaging

    NASA Astrophysics Data System (ADS)

    Kolbin, A. I.; Shimansky, V. V.

    2014-04-01

    We developed a code for imaging the surfaces of spotted stars by a set of circular spots with a uniform temperature distribution. The flux from the spotted surface is computed by partitioning the spots into elementary areas. The code takes into account the passing of spots behind the visible stellar limb, limb darkening, and overlapping of spots. Modeling of light curves includes the use of recent results of the theory of stellar atmospheres needed to take into account the temperature dependence of flux intensity and limb darkening coefficients. The search for spot parameters is based on the analysis of several light curves obtained in different photometric bands. We test our technique by applying it to HII 1883.

  5. HII 2407: AN ECLIPSING BINARY REVEALED BY K2 OBSERVATIONS OF THE PLEIADES

    SciTech Connect

    David, Trevor J.; Hillenbrand, Lynne A.; Zhang, Celia; Riddle, Reed L.; Stauffer, John; Rebull, L. M.; Cody, Ann Marie; Conroy, Kyle; Stassun, Keivan G.; Pope, Benjamin; Aigrain, Suzanne; Gillen, Ed; Cameron, Andrew Collier; Barrado, David; Isaacson, Howard; Marcy, Geoffrey W.; Ziegler, Carl; Law, Nicholas M.; Baranec, Christoph

    2015-11-20

    The star HII 2407 is a member of the relatively young Pleiades star cluster and was previously discovered to be a single-lined spectroscopic binary. It is newly identified here within Kepler/K2 photometric time series data as an eclipsing binary system. Mutual fitting of the radial velocity and photometric data leads to an orbital solution and constraints on fundamental stellar parameters. While the primary has arrived on the main sequence, the secondary is still pre-main sequence and we compare our results for the M/M{sub ⊙} and R/R{sub ⊙} values with stellar evolutionary models. We also demonstrate that the system is likely to be tidally synchronized. Follow-up infrared spectroscopy is likely to reveal the lines of the secondary, allowing for dynamically measured masses and elevating the system to benchmark eclipsing binary status.

  6. Perfis de temperatura eletrônica em regiões HII

    NASA Astrophysics Data System (ADS)

    Copetti, M. V. F.

    2003-08-01

    As flutuações de temperatura eletrônica em regiões HII, inicialmente propostas para explicar as discrepâncias entre os valores de temperatura obtidos por diferentes métodos, têm sido apontadas como a causa mais provável das enormes diferenças encontradas entre as abundâncias químicas medidas através de linhas excitadas colisionalmente e de linhas de recombinação. Recentemente têm sido reportadas tentativas de detecção e quantificação diretas das flutuações de temperatura eletrônica através de medidas ponto a ponto, obtidas por meio de espectroscopia de fenda longa, das razões de linhas [OIII]l4263/l5007 e [NII]l5755/l6584, principais sensores de temperatura. Neste trabalho, utilizamos o código numérico de fotoionização Cloudy para avaliar a confiabilidade desse procedimento. Concluímos que, para valores de densidade eletrônica e de temperatura efetiva da estrela ionizante típicos das regiões HII, os perfis superficiais de temperatura obtidos via medidas do sensor [OIII]l4263/l5007 são bons traçadores dos gradientes internos de temperatura eletrônica. Já os perfis de temperatura eletrônica medidos por meio da razão [NII]l5755/l6584 não reproduzem os gradientes verdadeiros de temperatura.

  7. T-cell compartment involvement in two high antibody responder lines of mice (HI and HII Biozzi mice) respectively susceptible and resistant to collagen-induced arthritis.

    PubMed

    Lima, G C; Zyad, A; Decreusefond, C; Mevel, J C; Stiffel, C; Mouton, D; Couderc, J

    1993-08-01

    The T-cell compartment was investigated in two high antibody responder lines of mice respectively susceptible (HI) and resistant (HII) to chicken collagen (CII)-induced arthritis (CIA). Previous data had shown that both lines were high anti-CII Ab producers, without any TCR V-beta gene defect or membrane expression impairment. The present studies demonstrate that anti-CII proliferation is much lower in HII than in HI. These results are confirmed by the limiting dilution analysis of anti-CII T-precursor frequencies (1/991 in HI and 1/12175 in HII). The percentage of CD8+ T cells is constitutively higher in HII mice, this difference increasing after CII immunization. This finding suggests a suppressive effect accounting for resistance to CIA. However, no restoration of specific response was achieved by in-vivo or in-vitro depletion of CD8+ T cells. T clones specific for Chicken CII could be obtained only from primed HI mice. Four of five clones with CD8+ phenotype proliferated in vitro to native and denatured CII and showed cytotoxic function in an anti-CD3 redirected assay. The CD4+ clone was shown to proliferate on both HI and HII-pulsed APC, which rules out a major CII processing/presentation defect in HII.

  8. RpoHII Activates Oxidative-Stress Defense Systems and Is Controlled by RpoE in the Singlet Oxygen-Dependent Response in Rhodobacter sphaeroides▿ †

    PubMed Central

    Nuss, Aaron M.; Glaeser, Jens; Klug, Gabriele

    2009-01-01

    Photosynthetic organisms need defense systems against photooxidative stress caused by the generation of highly reactive singlet oxygen (1O2). Here we show that the alternative sigma factor RpoHII is required for the expression of important defense factors and that deletion of rpoHII leads to increased sensitivity against exposure to 1O2 and methylglyoxal in Rhodobacter sphaeroides. The gene encoding RpoHII is controlled by RpoE, and thereby a sigma factor cascade is constituted. We provide the first in vivo study that identifies genes controlled by an RpoHII-type sigma factor, which is widely distributed in the Alphaproteobacteria. RpoHII-dependent genes encode oxidative-stress defense systems, including proteins for the degradation of methylglyoxal, detoxification of peroxides, 1O2 scavenging, and redox and iron homeostasis. Our experiments indicate that glutathione (GSH)-dependent mechanisms are involved in the defense against photooxidative stress in photosynthetic bacteria. Therefore, we conclude that systems pivotal for the organism's defense against photooxidative stress are strongly dependent on GSH and are specifically recognized by RpoHII in R. sphaeroides. PMID:18978062

  9. H-II Transfer Vehicle (HTV) and the Operations Concept for Extravehicular Activity (EVA) Hardware

    NASA Technical Reports Server (NTRS)

    Chullen, Cinda; Blome, Elizabeth; Tetsuya, Sakashita

    2011-01-01

    With the retirement of the Space Shuttle fleet imminent in 2011, a new operations concept will become reality to meet the transportation challenges of the International Space Station (ISS). The planning associated with the retirement of the Space Shuttle has been underway since the announcement in 2004. Since then, several companies and government entities have had to look for innovative low-cost commercial orbital transportation systems to continue to achieve the objectives of ISS delivery requirements. Several options have been assessed and appear ready to meet the large and demanding delivery requirements of the ISS. Options that have been identified that can facilitate the challenge include the Russian Federal Space Agency's Soyuz and Progress spacecraft, European Space Agency's Automated Transfer Vehicle (ATV), and the Japan Aerospace Exploration Agency's (JAXA s) H-II Transfer Vehicle (HTV). The newest of these options is the JAXA's HTV. This paper focuses on the HTV, mission architecture and operations concept for Extra-Vehicular Activities (EVA) hardware, the associated launch system, and details of the launch operations approach.

  10. Molecular dynamics approach to water structure of HII mesophase of monoolein

    NASA Astrophysics Data System (ADS)

    Kolev, Vesselin; Ivanova, Anela; Madjarova, Galia; Aserin, Abraham; Garti, Nissim

    2012-02-01

    The goal of the present work is to study theoretically the structure of water inside the water cylinder of the inverse hexagonal mesophase (HII) of glyceryl monooleate (monoolein, GMO), using the method of molecular dynamics. To simplify the computational model, a fixed structure of the GMO tube is maintained. The non-standard cylindrical geometry of the system required the development and application of a novel method for obtaining the starting distribution of water molecules. A predictor-corrector schema is employed for generation of the initial density of water. Molecular dynamics calculations are performed at constant volume and temperature (NVT ensemble) with 1D periodic boundary conditions applied. During the simulations the lipid structure is kept fixed, while the dynamics of water is unrestrained. Distribution of hydrogen bonds and density as well as radial distribution of water molecules across the water cylinder show the presence of water structure deep in the cylinder (about 6 Å below the GMO heads). The obtained results may help understanding the role of water structure in the processes of insertion of external molecules inside the GMO/water system. The present work has a semi-quantitative character and it should be considered as the initial stage of more comprehensive future theoretical studies.

  11. H-II Transfer Vehicle (HTV) and the Operations Concept for Extravehicular Activity (EVA) Hardware

    NASA Technical Reports Server (NTRS)

    Chullen, Cinda

    2010-01-01

    With the retirement of the Space Shuttle fleet imminent in 2011, a new concept of operations will become reality to meet the transportation challenges of the International Space Station (ISS). The planning associated with the retirement of the Space Shuttle has been underway since the announcement in 2004. Since then, several companies and government entities have had to look for innovative low-cost commercial orbital transportation systems to continue to achieve the objectives of ISS delivery requirements. Several options have been assessed and appear ready to meet the large and demanding delivery requirements of the ISS. Options that have been identified that can facilitate the challenge include the Russian Federal Space Agency's Soyuz and Progress spacecraft, European Space Agency's Automated Transfer Vehicle (ATV), the Japan Aerospace Exploration Agency's (JAXA's) H-II Transfer Vehicle (HTV) and the Boeing Delta IV Heavy (DIV-H). The newest of these options is the JAXA's HTV. This paper focuses on the HTV, mission architecture and operations concept for Extra-Vehicular Activities (EVA) hardware, the associated launch system, and details of the launch operations approach.

  12. The metal abundance of circumnuclear star-forming regions in early-type spirals. Spectrophotometric observations

    NASA Astrophysics Data System (ADS)

    Díaz, Ángeles I.; Terlevich, Elena; Castellanos, Marcelo; Hägele, Guillermo F.

    2007-11-01

    We have obtained long-slit observations in the optical and near-infrared of 12 circumnuclear HII regions [circumnuclear star-forming regions (CNSFR)] in the early-type spiral galaxies NGC2903, 3351 and 3504 with the aim of deriving their chemical abundances. Only for one of the regions, the [SIII] λ6312Å was detected providing, together with the nebular [SIII] lines at λλ9069, 9532Å, a value of the electron temperature of . A semi-empirical method for the derivation of abundances in the high metallicity regime is presented. We obtain abundances which are comparable to those found in high metallicity disc HII regions from direct measurements of electron temperatures and consistent with solar values within the errors. The region with the highest oxygen abundance is R3+R4 in NGC3504, 12 + log(O/H) = 8.85, about 1.5 solar if the solar oxygen abundance is set at the value derived by Asplund, Grevesse & Sauval, 12 + log(O/H)solar = 8.66 +/- 0.05. Region R7 in NGC3351 has the lowest oxygen abundance of the sample, about 0.6 times solar. In all the observed CNSFR the O/H abundance is dominated by the O+/H+ contribution, as is also the case for high metallicity disc HII regions. For our observed regions, however, also the S+/S2+ ratio is larger than one, contrary to what is found in high metallicity disc HII regions for which, in general, the sulphur abundances are dominated by S2+/H+. The derived N/O ratios are in average larger than those found in high metallicity disc HII regions and they do not seem to follow the trend of N/O versus O/H which marks the secondary behaviour of nitrogen. On the other hand, the S/O ratios span a very narrow range between 0.6 and 0.8 of the solar value. As compared to high metallicity disc HII regions, CNSFR show values of the O23 and the N2 parameters whose distributions are shifted to lower and higher values, respectively, hence, even though their derived oxygen and sulphur abundances are similar, higher values would in principle be

  13. Star forming regions in gas-rich SO galaxies

    NASA Technical Reports Server (NTRS)

    Pogge, Richard W.; Eskridge, Paul B.

    1987-01-01

    The first results of an H alpha imaging survey of HI rich SO galaxies, which were searched for HII regions and other sources of emission, are presented. The charge coupled device H alpha interference filter images were made of 16 galaxies. Eight of these galaxies show evidence for on-going star formation, one has nuclear emission but no HII regions, and the remaining seven have no emissions detected within well defined upper limits. With the exception of one notably peculiar galaxy in which the emission from HII regions appears pervasive, the HII regions are either organized into inner-disk rings or randomly distributed throughout the disk. A few of these galaxies are found to be clearly not SO's; or peculiar objects atypical of the SO class. Using simple models star formation rates (SFRs) and gas depletion times from the observed H alpha fluxes were estimated. In general, the derived SFRs are much lower than those found in isolated field spiral galaxies and the corresponding gas depletion time scales are also longer.

  14. Characteristics of low energy ions in the Heavy Ions In Space (HIIS) experiment

    NASA Technical Reports Server (NTRS)

    Kleis, Thomas; Tylka, Allan J.; Boberg, Paul R.; Adams, James H., Jr.; Beahm, Lorraine P.

    1995-01-01

    We present preliminary data on heavy ions (Z greater than or equal to 10) detected in the topmost Lexan sheets of the track detector stacks of the Heavy Ions in space (HIIS) experiment (M0001) on LDEF. The energy interval covered by these observations varies with the element, with (for example) Ne observable at 18-100 MeV nuc and Fe at 45-200 MeV/nuc. All of the observed ions are at energies far below the geomagnetic cutoff for fully-ionized particles at the LDEF orbit. Above 50 MeV/nuc (where most of our observed particles are Fe), the ions arrive primarily from the direction of lowest geomagnetic cutoff. This suggests that these particles originate outside the magnetosphere from a source with a steeply-falling spectrum and may therefore be associated with solar energetic particle (SEP) events. Below 50 MeV/nuc, the distribution of arrival directions suggests that most of the observed heavy ions are trapped in the Earth's magnetic field. Preliminary analysis, however, shows that these trapped heavy ions have a very surprising composition: they include not only Ne and Ar, which are expected from the trapping of anomalous cosmic rays (ACR's), but also Mg and Si, which are not part of the anomalous component. Our preliminary analysis shows that trapped heavy ions at 12 less than or equal to Zeta less than or equal to 14 have a steeply-falling spectrum, similar to that reported by the Kiel experiment (exp 1,2,3) on LDEF (M0002) for trapped Ar and Fe at E less than 50 MeV/nuc. The trapped Mg, Si, and Fe may also be associated with SEP events, but the mechanism by which they have appeared to deep in the inner magnetosphere requires further theoretical investigation.

  15. Characteristics of low energy ions in the Heavy Ions In Space (HIIS) experiment

    NASA Astrophysics Data System (ADS)

    Kleis, Thomas; Tylka, Allan J.; Boberg, Paul R.; Adams, James H., Jr.; Beahm, Lorraine P.

    1995-02-01

    We present preliminary data on heavy ions (Z greater than or equal to 10) detected in the topmost Lexan sheets of the track detector stacks of the Heavy Ions in space (HIIS) experiment (M0001) on LDEF. The energy interval covered by these observations varies with the element, with (for example) Ne observable at 18-100 MeV nuc and Fe at 45-200 MeV/nuc. All of the observed ions are at energies far below the geomagnetic cutoff for fully-ionized particles at the LDEF orbit. Above 50 MeV/nuc (where most of our observed particles are Fe), the ions arrive primarily from the direction of lowest geomagnetic cutoff. This suggests that these particles originate outside the magnetosphere from a source with a steeply-falling spectrum and may therefore be associated with solar energetic particle (SEP) events. Below 50 MeV/nuc, the distribution of arrival directions suggests that most of the observed heavy ions are trapped in the Earth's magnetic field. Preliminary analysis, however, shows that these trapped heavy ions have a very surprising composition: they include not only Ne and Ar, which are expected from the trapping of anomalous cosmic rays (ACR's), but also Mg and Si, which are not part of the anomalous component. Our preliminary analysis shows that trapped heavy ions at 12 less than or equal to Zeta less than or equal to 14 have a steeply-falling spectrum, similar to that reported by the Kiel experiment (exp 1,2,3) on LDEF (M0002) for trapped Ar and Fe at E less than 50 MeV/nuc. The trapped Mg, Si, and Fe may also be associated with SEP events, but the mechanism by which they have appeared to deep in the inner magnetosphere requires further theoretical investigation.

  16. MS_RHII-RSD, a Dual-Function RNase HII-(p)ppGpp Synthetase from Mycobacterium smegmatis

    PubMed Central

    Murdeshwar, Maya S.

    2012-01-01

    In the noninfectious soil saprophyte Mycobacterium smegmatis, intracellular levels of the stress alarmones guanosine tetraphosphate and guanosine pentaphosphate, together termed (p)ppGpp, are regulated by the enzyme RelMsm. This enzyme consists of a single, bifunctional polypeptide chain that is capable of both synthesizing and hydrolyzing (p)ppGpp. The relMsm knockout strain of M. smegmatis (ΔrelMsm) is expected to show a (p)ppGpp null [(p)ppGpp0] phenotype. Contrary to this expectation, the strain is capable of synthesizing (p)ppGpp in vivo. In this study, we identify and functionally characterize the open reading frame (ORF), MSMEG_5849, that encodes a second functional (p)ppGpp synthetase in M. smegmatis. In addition to (p)ppGpp synthesis, the 567-amino-acid-long protein encoded by this gene is capable of hydrolyzing RNA·DNA hybrids and bears similarity to the conventional RNase HII enzymes. We have classified this protein as actRelMsm in accordance with the recent nomenclature proposed and have named it MS_RHII-RSD, indicating the two enzymatic activities present [RHII, RNase HII domain, originally identified as domain of unknown function 429 (DUF429), and RSD, RelA_SpoT nucleotidyl transferase domain, the SYNTH domain responsible for (p)ppGpp synthesis activity]. MS_RHII-RSD is expressed and is constitutively active in vivo and behaves like a monofunctional (p)ppGpp synthetase in vitro. The occurrence of the RNase HII and (p)ppGpp synthetase domains together on the same polypeptide chain is suggestive of an in vivo role for this novel protein as a link connecting the essential life processes of DNA replication, repair, and transcription to the highly conserved stress survival pathway, the stringent response. PMID:22636779

  17. Statistics and properties of H II regions in a sample of grand design galaxies I. Luminosity functions.

    NASA Astrophysics Data System (ADS)

    Rozas, M.; Beckman, J. E.; Knapen, J. H.

    1996-03-01

    We present new high quality continuum-subtracted Hα images of the grand-design galaxies NGC 157, NGC 3631, NGC 6764 and NGC 6951. We have determined the positions, angular sizes, and fluxes of their individual HII regions, and describe statistical properties of the HII region samples. We construct luminosity functions for all the HII regions in the disc and separately for arm and interarm zones for each galaxy. The slopes of the luminosity functions for the complete sample agree well with values published for other spiral galaxies of comparable morphological type. For three galaxies we determined the slopes of the luminosity functions for the spiral arm and interarm zones separately. We find that for NGC 157, NGC 3631, and NGC 6951 these slopes are equal within the errors of determination. We compare our results to those found from earlier work, specifically for M51 and NGC 6814, and discuss implications for massive star forming processes.

  18. RNase HII Saves rnhA Mutant Escherichia coli from R-Loop-Associated Chromosomal Fragmentation.

    PubMed

    Kouzminova, Elena A; Kadyrov, Farid F; Kuzminov, Andrei

    2017-09-15

    The rnhAB mutant Escherichia coli, deficient in two RNase H enzymes that remove both R-loops and incorporated ribonucleotides (rNs) from DNA, grow slowly, suggesting accumulation of rN-containing DNA lesions (R-lesions). We report that the rnhAB mutants have reduced viability, form filaments with abnormal nucleoids, induce SOS, and fragment their chromosome, revealing replication and/or segregation stress. R-loops are known to interfere with replication forks, and sensitivity of the double rnhAB mutants to translation inhibition points to R-loops as precursors for R-lesions. However, the strict specificity of bacterial RNase HII for RNA-DNA junctions indicates that R-lesions have rNs integrated into DNA. Indeed, instead of relieving problems of rnhAB mutants, transient inhibition of replication from oriC kills them, suggesting that oriC-initiated replication removes R-loops instead of compounding them to R-lesions. Yet, replication from an R-loop-initiating plasmid origin kills the double rnhAB mutant, revealing generation of R-lesions by R-loop-primed DNA synthesis. These R-lesions could be R-tracts, contiguous runs of ≥4 RNA nucleotides within DNA strand and the only common substrate between the two bacterial RNase H enzymes. However, a plasmid relaxation test failed to detect R-tracts in DNA of the rnhAB mutants, although it readily detected R-patches (runs of 1-3 rNs). Instead, we detected R-gaps, single-strand gaps containing rNs, in the chromosomal DNA of the rnhAB mutant. Therefore, we propose that RNase H-deficient mutants convert some R-loops into R-tracts, which progress into R-gaps and then to double-strand breaks-explaining why R-tracts do not accumulate in RNase H-deficient cells, while double-strand breaks do. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. H(II) mesophase and peptide cell-penetrating enhancers for improved transdermal delivery of sodium diclofenac.

    PubMed

    Cohen-Avrahami, Marganit; Aserin, Abraham; Garti, Nissim

    2010-06-01

    This study develops a novel transdermal delivery vehicle for the enhanced delivery of sodium diclofenac (Na-DFC). The system utilizes the advantages of reversed hexagonal lyotropic liquid crystals (H(II)LC), combined with a peptide cell penetration enhancer (CPE), creating together an adaptable system that provides versatile options in the field of transdermal delivery. This enhancer peptide is based on a family of amphipatic peptides that exhibit improved membrane permeability. Franz permeation cell experiments revealed that the peptide enhancer (RALA) improved Na-DFC skin penetration of the liquid crystal 2.2-fold. We studied the structural effects of RALA solubilization on the H(II) mesophase. RALA acts as a chaotropic agent, interfering in the structure of the water, and causes a measurable swelling of the aqueous cylinders by 5A. Small angle X-ray scattering (SAXS) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) measurements reveal enhanced hydration of the glycerol monooleate (GMO) headgroups and a 6.5% increase in the fraction of non-freezable water resulting from RALA incorporation. RALA caused a gradual increase in the GMO effective headgroup area due to the hydration, leading eventually to a transform of the hexagonal structure towards a lamellar one. Circular dichroism and ATR-FTIR measurements showed a conservation of the peptide structure when incorporated into the H(II) mesophase. The combined H(II)LC-CPE systems can serve as high potential vehicles for a variety of drugs, as they can easily be modified by varying the composition and temperature, according to the required dose and delivery features.

  20. Structural rearrangements and interaction within H(II) mesophase induced by cosolubilization of vitamin E and ascorbic acid.

    PubMed

    Bitan-Cherbakovsky, Liron; Yuli-Amar, Idit; Aserin, Abraham; Garti, Nissim

    2009-11-17

    We investigated the effect of ascorbic acid (AA) cosolubilized with vitamin E (VE) on reverse hexagonal (H(II)) mesophase. The H(II) phase comprises monoolein (GMO)/d-alpha-tocopherol (VE) in a ratio of 90/10 by weight and 12.5 wt % water. The macrostructural characteristics of this system were determined by polarized light microscopy and small-angle X-ray scattering measurements. We used differential scanning calorimetry and attenuated total reflectance Fourier transform infrared to characterize the microstructure, the vibration of the functional groups, and the location of the AA guest molecule. AA was incorporated to the system in two steps: 1-4 wt % AA and 5-6 wt % AA. We compared this system to one containing tricaprylin as the oil phase, as previously reported. These measurements revealed that AA is localized first in the water rich-core and in the interface, and acts as a chaotropic molecule that decreases the water melting point. When a larger quantity of AA (5-6 wt %) is added, the system is saturated, and the AA is located in the inner cylinder and manifested by more moderate distortion. The addition of AA also causes alteration in the behavior of the GMO hydrocarbon chains and makes them more flexible. Further addition of AA caused the GMO hydrocarbon chain to be more solvated by the VE hydrocarbon chain and enabled additional migration of VE; hence a decrease in the hydrophobic melting temperature occurred (similar to tricaprylin). Increasing the amount of AA weakened the bonding between the GMO and water and created new bonds between AA and GMO and AA with water.

  1. VizieR Online Data Catalog: HII regions and GMC in the Antennae (Zaragoza-Cardiel+, 2014)

    NASA Astrophysics Data System (ADS)

    Zaragoza-Cardiel, J.; Font, J.; Beckman, J. E.; Garcia-Lorenzo, B.; Erroz-Ferrer, S.; Gutierrez, L.

    2014-10-01

    We present two sets of observations of the Antennae: data cubes of emission in Hα from the ionized component of the interstellar medium and of emission in the CO(3-2) line from the molecular component. (4 data files).

  2. VizieR Online Data Catalog: Deep Chandra obs. of the giant HII region N11 in LMC (Naze+, 2014)

    NASA Astrophysics Data System (ADS)

    Naze, Y.; Wang, Q. D.; Chu, Y.-H.; Gruendl, R.; Oskinova, L.

    2014-09-01

    The Chandra ACIS-I observations of N11 were made in six separate segments (ObsID 8210, 8469, 8468, 8467, 8470 and 8211) within two months (June-July) in 2007. We found 165 sources in N11: 43 of them were detected with the highest confidence or smallest P value in the S band (soft 0.5-2keV), 5 in the H band (hard 2-8keV), and 117 in the T band (total 0.5-8keV). We further used Hα, [OIII], and [SII] images taken with the MOSAIC camera on the Blanco 4m Telescope at the Cerro Tololo Inter-American Observatory. The [OIII]λ5007 observations and the [SII]6716,6731 observations consist of four dithered 450s exposures for each location; these images were obtained on 2011 October 31. We have also used infrared observations made with the Spitzer Space Telescope from Gruendl & Chu (2009, Cat. J/ApJS/184/172). (3 data files).

  3. VizieR Online Data Catalog: Infrared colors in HII region Sh2-173 (Cichowolski+, 2009)

    NASA Astrophysics Data System (ADS)

    Cichowolski, S.; Romero, G. A.; Ortega, M. E.; Cappa, C. E.; Vasquez, J.

    2009-10-01

    Radio continuum data at 408 and 1420MHz, as well as 21cm spectral line data, were obtained using the Dominion Radio Astrophysical Observatory (DRAO) interferometer as part of the Canadian Galactic Plane Survey (CGPS) (Taylor et al. 2003, Cat. ). Radio continuum surveys at 325MHz (WENSS) (Rengelink et al., 1997, Cat. ), 2695MHz (Fuerst et al., 1990A&AS...85..691F) and 4850MHz (Condon et al., 1994AJ....107.1829C) were also used in this work. Mid-IR data were taken from the Midcourse Space Experiment (MSX) Galactic Plane Survey (Price et al., 2001AJ....121.2819P), and near-IR data were obtained from the 2MASS All-Sky Point Source Catalog (Skrutskie et al. 2006, Cat. ). (1 data file).

  4. Mid-infrared observations of methanol maser sites and ultracompact H ii regions: signposts of high-mass star formation

    NASA Astrophysics Data System (ADS)

    Walsh, A. J.; Bertoldi, F.; Burton, M. G.; Nikola, T.

    2001-09-01

    N-band (10.5μm) and/or Q-band (20.0μm) images taken with MANIAC on the ESO/MPI 2.2-m telescope are presented for 31 methanol maser sites and 19 ultracompact (UC) Hii regions. Most of the maser sites and UC Hii regions are coincident with mid-infrared (MIR) sources to within the positional uncertainties of ~3arcsec, consistent with the maser emission being powered by the MIR source. The IRAS source positions, however, do not always coincide with the MIR sources. Based on an average infrared spectral energy distribution, we deduce that the MIR objects are luminous enough that they should also produce a strong ionizing radiation. Some sources are consistent with stars of later spectral type, but not all can be. A number of maser sites show no detectable radio continuum emission associated with MIR emission, despite a powering source luminous enough potentially to produce an UC Hii region. Since no signs of an UC Hii region are detected here, these maser sites might be produced during a very early stage of stellar evolution. We present objects that show evidence of outflow activity stemming from a maser site, exhibiting CO and/or CS line profiles indicative of outflows coincident with the MIR source. These cases are promising examples of maser sites signposting the earliest stages of high-mass star formation.

  5. Development of X-ray computed tomography inspection facility for the H-II solid rocket boosters

    NASA Astrophysics Data System (ADS)

    Sasaki, M.; Fujita, T.; Fukushima, Y.; Shimizu, M.; Itoh, S.; Satoh, A.; Miyamoto, H.

    The National Space Development Agency of Japan (NASDA) initiated the development of an X-ray computed tomography (CT) equipment for the H-II solid rocket boosters (SRBs) in 1987 for the purpose of minimizing inspection time and achieving high cost-effectiveness. The CT facility has been completed in Jan. 1991 in Tanegashima Space Center for the inspection of the SRBs transported from the manufacturer's factory to the launch site. It was first applied to the qualification model SRB from Feb. to Apr. in 1991. Through the CT inspection of the SRB, it has been confirmed that inspection time decreased significantly compared with the X-ray radiography method and that even an unskilled inspector could find various defects. As a result, the establishment of a new reliable inspection method for the SRB has been verified. In this paper, the following are discussed: (1) the defect detectability of the CT equipment using a dummy SRB with various artificial defects, (2) the performance comparison between the CT method and the X-ray radiography method, (3) the reliability of the CT equipment, and (4) the radiation shield design of the nondestructive test building.

  6. Physical conditions of a HII galaxy with extraordinarily dense nucleus: Mrk996

    NASA Astrophysics Data System (ADS)

    Telles, E.; Thuan, T. X.; Izotov, Y. I.; Carrasco, E. R.

    2014-10-01

    We present an integral field spectroscopic study with the Gemini Multi-Object Spectrograph (GMOS) of the unusual blue compact dwarf (BCD) galaxy Mrk 996. We show through velocity and dispersion maps, emission-line intensity and ratio maps, and by a new technique of electron density limit imaging that the ionization properties of different regions in Mrk 996 are correlated with their kinematic properties. From the maps, we can spatially distinguish a very dense high-ionization zone with broad lines in the nuclear region, and a less dense low-ionization zone with narrow lines in the circumnuclear region. Four kinematically distinct systems of lines are identified in the integrated spectrum of Mrk 996, suggesting stellar wind outflows from a population of Wolf-Rayet (WR) stars in the nuclear region, superposed on an underlying rotation pattern. From the intensities of the blue and red bumps, we derive a population of ˜ 473 late nitrogen (WNL) stars and ˜ 98 early carbon (WCE) stars in the nucleus of Mrk 996, resulting in a high N(WR)/N(O+WR) of 0.19. We derive, for the outer narrow-line region, an oxygen abundance 12+log(O/H)=7.94 ± 0.30 (˜ 0.2 Z_{odot}) by using the direct T_e method derived from the detected narrow [O III]λ 4363 line. The nucleus of Mrk 996 is, however, nitrogen-enhanced by a factor of ˜ 20, in agreement with previous CLOUDY modeling. This nitrogen enhancement is probably due to nitrogen-enriched WR ejecta, but also to enhanced nitrogen line emission in a high-density environment. Although we have made use here of two new methods - Principal Component Analysis (PCA) tomography and a method for mapping low- and high-density clouds - to analyze our data, new methodology is needed to further exploit the wealth of information provided by integral field spectroscopy.

  7. Synaptic Elements for GABAergic Feed-Forward Signaling between HII Horizontal Cells and Blue Cone Bipolar Cells Are Enriched beneath Primate S-Cones

    PubMed Central

    Puller, Christian; Haverkamp, Silke; Neitz, Maureen; Neitz, Jay

    2014-01-01

    The functional roles and synaptic features of horizontal cells in the mammalian retina are still controversial. Evidence exists for feedback signaling from horizontal cells to cones and feed-forward signaling from horizontal cells to bipolar cells, but the details of the latter remain elusive. Here, immunohistochemistry and confocal microscopy were used to analyze the expression patterns of the SNARE protein syntaxin-4, the GABA receptor subunits α1 and ρ, and the cation-chloride cotransporters NKCC and KCC2 in the outer plexiform layer of primate retina. In macaque retina, as observed previously in other species, syntaxin-4 was expressed on dendrites and axon terminals of horizontal cells at cone pedicles and rod spherules. At cones, syntaxin-4 appeared densely clustered in two bands, at horizontal cell dendritic tips and at the level of desmosome-like junctions. Interestingly, in the lower band where horizontal cells may synapse directly onto bipolar cells, syntaxin-4 was highly enriched beneath short-wavelength sensitive (S) cones and colocalized with calbindin, a marker for HII horizontal cells. The enrichment at S-cones was not observed in either mouse or ground squirrel. Furthermore, high amounts of both GABA receptor and cation-chloride cotransporter subunits were found beneath primate S-cones. Finally, while syntaxin-4 was expressed by both HI and HII horizontal cell types, the intense clustering and colocalization with calbindin at S-cones indicated an enhanced expression in HII cells. Taken together, GABA receptors beneath cone pedicles, chloride transporters, and syntaxin-4 are putative constituents of a synaptic set of proteins which would be required for a GABA-mediated feed-forward pathway via horizontal cells carrying signals directly from cones to bipolar cells. PMID:24586460

  8. Unit cell structure of water-filled monoolein into inverted hexagonal (H(II)) mesophase modeled by molecular dynamics.

    PubMed

    Kolev, Vesselin L; Ivanova, Anela N; Madjarova, Galia K; Aserin, Abraham; Garti, Nissim

    2014-05-22

    The study investigates the unit cell structure of inverted hexagonal (H(II)) mesophase composed of monoolein (1-monoolein, GMO) and water using atomistic molecular dynamics methods without imposing any restraints on lipid and water molecules. Statistically meaningful and very contrast images of the radial mass density distribution, scrutinizing also the separate components water, monoolein, the polar headgroups of the lipids, the double bond, and the termini of the hydrocarbon chain (the tail), are obtained. The lipid/water interface structure is analyzed based on the obtained water density distribution, on the estimated number of hydrogen bonds per monoolein headgroup, and on the headgroup-water radial distribution functions. The headgroup mass density distribution demonstrates hexagonal shape of the monoolein/water interface that is well-defined at higher water/monoolein ratios. Water interacts with the headgroups by forming a three-layer diffusive mass density distribution, and each layer's shape is close to hexagonal, which is an indication of long-range structural interactions. It is found that the monoolein headgroups form a constant number of hydrogen bonds leaving an excessive amount of water molecules outside the first lipid coordination sphere. Furthermore, the quantity of water at the monoolein/water interface increases steadily upon extension of the unit cell, so the interface should have a very dynamic structure. Investigation of the hydrocarbon residues reveals high compression and well-expressed structuring of the tails. The tails form a very compressed and constrained structure of defined layers across the unit cell with properties corresponding to a more densely packed nonpolar liquid (oil). Due to the hexagonal shape the 2D packing frustration is constant and does not depend on the water content. All reported structural features are based on averaging of the atomic coordinates over the time-length of the simulation trajectories. That kind of

  9. Evolução química de galáxias HII anãs

    NASA Astrophysics Data System (ADS)

    Ferraresi, M., Jr.; Cuisinier, F.; Telles, E.

    2003-08-01

    Galáxias HII anãs são galáxias de baixa massa, com alto conteúdo de gás, e se encontram em uma fase intensa de formação estelar. A taxa de formação estelar está tão alta nestas galáxias que não pode ter se mantido durante sua vida inteira. O tempo máximo de duração do episódio atual de formação estelar deve ser no máximo de algumas dezenas de milhões de anos, bem inferior à idade destas galáxias. Isto leva naturalmente a idéia de que já aconteceram surtos anteriores. Abundâncias químicas oferecem uma ferramenta poderosa para investigar a história evolutiva destas galáxias, porque aumentam de geração em geração estelar. O hidrogênio, o oxigênio, o nitrogênio produzem algumas das linhas mais importantes em um gás foto-ionizado, permitindo a determinação das abundâncias destes elementos facilmente. A dispersão das abundâncias em oxigênio e nitrogênio é significativa, sendo maior que os erros observacionais. O oxigênio é produzido em estrelas massivas, que explodem quase instâneamente, enquanto o nitrogênio é produzido em estrelas de massa intermediária, que só o liberam depois de um atraso de @ 500 mihões de anos. Construímos um modelo de evolução química semi-analítico, utilizando rendimentos empíricos baseados nas abundâncias observadas destes dois elementos. Conseguimos através deste modelo rudimentar explicar nas galáxias de mais baixas metalicidades as abundâncias de oxigênio e de nitrogênio, assim como a dispersão dos dados observacionais devida a formação estelar descontínua, e isto com um número baixo de surtos (1 ou 2, no máximo 3).

  10. An atlas of H-alpha-emitting regions in M33: A systematic search for SS433 star candidates

    NASA Technical Reports Server (NTRS)

    Calzetti, Daniela; Kinney, Anne L.; Ford, Holland; Doggett, Jesse; Long, Knox S.

    1995-01-01

    We report finding charts and accurate positions for 432 compact H-alpha emitting regions in the Local Group galaxy M 33 (NGC 598), in an effort to isolate candidates for an SS433-like stellar system. The objects were extracted from narrow band images, centered in the rest-frame H-alpha (lambda 6563 A) and in the red continuum at 6100 A. The atlas is complete down to V approximately equal to 20 and includes 279 compact HII regions and 153 line emitting point-like sources. The point-like sources undoubtedly include a variety of objects: very small HII regions, early type stars with intense stellar winds, and Wolf-Rayet stars, but should also contain objects with the characteristics of SS433. This extensive survey of compact H-alpha regions in M 33 is a first step towards the identification of peculiar stellar systems like SS433 in external galaxies.

  11. Characterization of the nonlamellar cubic and HII structures of lipid A from Salmonella enterica serovar Minnesota by X-ray diffraction and freeze-fracture electron microscopy.

    PubMed

    Brandenburg, K; Richter, W; Koch, M H; Meyer, H W; Seydel, U

    1998-01-01

    The aggregate structures of lipid A, the 'endotoxic principle' of bacterial lipopolysaccharide (LPS), from rough mutant Salmonella enterica sv. Minnesota R595 was analyzed at different water content, cation (Mg2+) concentration, and temperature applying synchrotron radiation X-ray diffraction and, in selected cases, freeze-fracture electron microscopy. The X-ray diffraction spectra prove the existence of different lamellar, mixed lamellar/cubic, various cubic, and inverted hexagonal (HII) structures depending on ambient conditions. The three mainly bicontinuous cubic phases Q224, Q229, and Q230 can be observed between 30 and 50 degrees C in narrow water and cation concentration ranges. Above 50 degrees C, Q212 an intermediate phase between bicontinuous and micellar is adopted. In freeze-fracture electron microscopic experiments, cubic structures of these symmetries are not readily detected, which can be understood in the light of changes in hydration during freezing and the metastability of these phases. However, 'lipidic particles' closely related to cubic phases are observed. Above 65-70 degrees C, the existence of the HII phase with hexagonal periodicities dH between 4.0 and 6.0 nm for different hydration states is shown using both techniques. Possible biological implications for the preference of lipid A for nonlamellar structures are discussed.

  12. Discovery of Very High Energy Gamma-Ray Emission in the W 28 (G6.4-0.1) Region and Multiwavelength Comparisons

    SciTech Connect

    Rowell, G.; Brion, E.; Reimer, O.; Moriguchi, Y.; Fukui, Yasuo; Djannati-Atai, A.; Funk, S.; /Stanford U., HEPL /KIPAC, Menlo Park

    2007-10-29

    H.E.S.S. observations of the old-age (>10{sup 4} yr; {approx} 0.5 degree diameter) composite supernova remnant (SNR)W28 reveal very high energy (VHE) {gamma}-ray emission situated at its northeastern and southern boundaries. The northeastern VHE source (HESS J1801-233) is in an area where W 28 is interacting with a dense molecular cloud, containing OH masers, local radio and X-ray peaks. The southern VHE sources (HESS J1800-240 with components labeled A, B and C) are found in a region occupied by several HII regions, including the ultracompact HII region W 28A2. Our analysis of NANTEN CO data reveals a dense molecular cloud enveloping this southern region, and our reanalysis of EGRET data reveals MeV/GeV emission centered on HESS J1801-233 and the northeastern interaction region.

  13. Disk Evaporation in Star Forming Regions

    NASA Technical Reports Server (NTRS)

    Hollenbach, David; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    Young stars produce sufficient ultraviolet photon luminosity and mechanical luminosity in their winds to significantly affect the structure and evolution of the accretion disks surrounding them. The Lyman continuum photons create a nearly static, ionized, isothermal 10(exp 4) K atmosphere forms above the neutral disk at small distances from the star. Further out, they create a photoevaporative flow which relatively rapidly destroys the disk. The resulting slow (10-50 km/s) ionized outflow, which persists for approx. greater than 10(exp 5) years for disk masses M(sub d) approx. 0.3M(sub *), may explain the observational characteristics of many ultracompact HII regions. We compare model results to the observed radio free-free spectra and luminosities of ultracompact HII regions and to the interesting source MWC349, which is observed to produce hydrogen masers. We apply the results to Ae and Be stars in order to determine the lifetimes of disks around such stars. We also apply the results to the early solar nebula to explain the the dispersal of the solar nebula and the differences in hydrogen content in the giant planets. Finally, we model the small bright objects ("proplyds") observed in the Orion Nebula as disks around young, low mass stars which are externally illuminated by the UV photons from the nearby massive star Theta(sup 1) C.

  14. Disk Evaporation in Star Forming Regions

    NASA Technical Reports Server (NTRS)

    Hollenbach, David; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    Young stars produce sufficient ultraviolet photon luminosity and mechanical luminosity in their winds to significantly affect the structure and evolution of the accretion disks surrounding them. The Lyman continuum photons create a nearly static, ionized, isothermal 10(exp 4) K atmosphere forms above the neutral disk at small distances from the star. Further out, they create a photoevaporative flow which relatively rapidly destroys the disk. The resulting slow (10-50 km/s) ionized outflow, which persists for approx. greater than 10(exp 5) years for disk masses M(sub d) approx. 0.3M(sub *), may explain the observational characteristics of many ultracompact HII regions. We compare model results to the observed radio free-free spectra and luminosities of ultracompact HII regions and to the interesting source MWC349, which is observed to produce hydrogen masers. We apply the results to Ae and Be stars in order to determine the lifetimes of disks around such stars. We also apply the results to the early solar nebula to explain the the dispersal of the solar nebula and the differences in hydrogen content in the giant planets. Finally, we model the small bright objects ("proplyds") observed in the Orion Nebula as disks around young, low mass stars which are externally illuminated by the UV photons from the nearby massive star Theta(sup 1) C.

  15. Discrepancies between the [O iii] and [S iii] temperatures in H ii regions

    NASA Astrophysics Data System (ADS)

    Binette, L.; Matadamas, R.; Hägele, G. F.; Nicholls, D. C.; Magris C., G.; Peña-Guerrero, M. Á.; Morisset, C.; Rodríguez-González, A.

    2012-11-01

    Context. Analysis of published [O iii] and [S iii] temperatures measurements of emission line objects consisting of Hii galaxies, giant extragalactic Hii regions, Galactic Hii regions, and Hii regions from the Magellanic Clouds reveal that the [O iii] temperatures are higher than the corresponding values from [S iii] in most objects with gas metallicities in excess of 0.2 solar. For the coolest nebulae (the highest metallicities), the [O iii] temperature excess can reach ~3000 K. Aims: We look for an explanation for these temperature differences and explore the parameter space of models with the aim of reproducing the observed trend of TO iii > TS iii in Hii regions with temperatures below 14 000 K. Methods: Using standard photoionization models, we varied the ionization parameter, the hardness of the ionizing continuum, and the gas metallicities in order to characterize how models behave with respect to the observations. We introduced temperature inhomogeneities and varied their mean squared amplitude t2 . We explored the possibility of inhomogeneities in abundances by combining two models of widely different metallicity. We calculated models that consider the possibility of a non-Maxwell-Boltzmann energy distribution (a κ-distribution) for the electron energies. We also considered shock heating within the photoionized nebula. Results: Simple photoionization calculations yield nearly equal [O iii] and [S iii] temperatures in the domain of interest. Hence these models fail to reproduce the [O iii] temperature excess. Models that consider temperature inhomogeneities, as measured by the mean squared amplitude t2 , also fail in the regime where TO iii < 14 000 K. Three options remain that can reproduce the observed excess in TO iii temperatures: (1) large metallicity inhomogeneities in the nebula; a (2) κ-distribution for the electron energies; and (3) shock waves that propagate in the photoionized plasma at velocities ~60 km s-1. Conclusions: The observed nebular

  16. Looking Closely at "Medusa": Star Forming Regions in NGC 4194

    NASA Technical Reports Server (NTRS)

    Weistrop, D.; Eggers, D.; Nelson, C. H.; Kaiser, M. E.

    2004-01-01

    The "Medusa" (NGC 4194, Mrk 201) is a blue compact galaxy, with strong far infrared and radio emission. Ground-based observations exhibit a distorted image with a tidal tail and regions of strong star formation. A population of massive O and early B stars is evident from the IUE spectra HST survey of Seyfert and starburst galaxies notes NCG 4194 is an HII galaxy with lumpy HII regions and knots. The central starburst is apparently produced by a galaxy merger. As part of an investigation of star formation in interacting galaxies, we have obtained ultraviolet and visible images of the central regions of NGC 4194 with the Space Telescope Imaging Spectrograph on HST. Imaging was obtained in two ultraviolet (FUV-MAMA+F25QTZ, NUV-MAMA+F25CN182) and one visible (CCD+F28X50LP) band. Individual star forming knots (at HST resolution) have been identified. We present sized and luminosities for the individual knots, and the knot luminosity function. We compare our data to current starburst models to constrain stellar ages and populations. Knot characteristics as a function of location in the galaxy will also be discussed.

  17. Looking Closely at "Medusa": Star Forming Regions in NGC 4194

    NASA Technical Reports Server (NTRS)

    Weistrop, D.; Eggers, D.; Nelson, C. H.; Kaiser, M. E.

    2004-01-01

    The "Medusa" (NGC 4194, Mrk 201) is a blue compact galaxy, with strong far infrared and radio emission. Ground-based observations exhibit a distorted image with a tidal tail and regions of strong star formation. A population of massive O and early B stars is evident from the IUE spectra HST survey of Seyfert and starburst galaxies notes NCG 4194 is an HII galaxy with lumpy HII regions and knots. The central starburst is apparently produced by a galaxy merger. As part of an investigation of star formation in interacting galaxies, we have obtained ultraviolet and visible images of the central regions of NGC 4194 with the Space Telescope Imaging Spectrograph on HST. Imaging was obtained in two ultraviolet (FUV-MAMA+F25QTZ, NUV-MAMA+F25CN182) and one visible (CCD+F28X50LP) band. Individual star forming knots (at HST resolution) have been identified. We present sized and luminosities for the individual knots, and the knot luminosity function. We compare our data to current starburst models to constrain stellar ages and populations. Knot characteristics as a function of location in the galaxy will also be discussed.

  18. Outflow activity in the UCHII region G045.47+0.05

    NASA Astrophysics Data System (ADS)

    Ortega, M. E.; Paron, S.; Cichowolski, S.; Rubio, M.; Dubner, G.

    2012-10-01

    Aims: This work aims at investigating the molecular gas in the surroundings of the ultra-compact HII region G045.47+0.05 looking for evidence of molecular outflows. Methods: We carried out observations towards a region of 2' × 2' centered at RA = 19h14m25.6s, Dec = +11°09'27.6''(J2000) using the Atacama Submillimeter Telescope Experiment (ASTE; Chile) in the 12CO J = 3-2, 13CO J = 3-2, HCO+J = 4-3, and CS J = 7-6 lines with an angular resolution of 22''. We complement these observations with public infrared data. Results: We characterize the physical parameters of the molecular clump where G045.47+0.0 is embedded. The detection of the CS J = 7-6 line emission in the region reveals that the ultra-compact HII region G045.47+0.0 has not completely disrupted the dense gas where it was born. The HCO+ abundance observed towards G045.47+0.0 suggests there is molecular outflow activity in the region. From the analysis of the 12CO J = 3-2 transition we report bipolar molecular outflows with a total mass of about 300 M⊙. We derive a dynamical time (flow's age) of about 105 yr for the outflow gas, in agreement with the presence of an ultra-compact HII region. We identify the source 2MASS 19142564+1109283 as the massive protostar candidate to drive the molecular outflows. Based on the analysis of its spectral energy distribution, we infer that it is an early B-type star of about 15 M⊙. The results of this work support the scenario where the formation of massive stars, at least up to early B-type stars, is similar to that of low-mass stars.

  19. UV extinction and IR emission in diffuse H2 regions

    NASA Technical Reports Server (NTRS)

    Aannestad, Per A.

    1994-01-01

    HII regions occupy a unique position in our understanding of the physical relationships between stars, the interstellar medium, and galactic structure. Observations show a complex interaction between a newly formed hot star and its surroundings. In particular, the ultraviolet radiation from the stars modifies the pre-existing dust, which again affects both the amount of ionizing radiation absorbed by the gas, and the infrared spectrum emitted by the heated dust. The aim of this project was to use UV and far-UV observations to gain information on the nebular dust, and to use this dust to model the far-IR emission, for a consistent picture of a few selected diffuse HII regions. Using archival data from the IUE and Voyager data banks and computed model atmospheres, we have deduced extinction curves for early-types stars. The requisite spectral resolution turned out to be a major task. We have successfully modelled these curves in terms of a multi-component, multi-size distribution of dust grains, and interpret the differences in the curves as primarily due to the presence or non-presence of intermediate size grains (0.01 to 0.04 micron). Much smaller (0.005 micron) grains must also be present. Finally, we have made calculations of the temperature fluctuations and the corresponding infra-red emission in such small grains.

  20. Hubble Space Telescope Hx Imaging of Star-forming Galaxies at z approximately equal to 1-1.5: Evolution in the Size and Luminosity of Giant H II Regions

    NASA Technical Reports Server (NTRS)

    Livermore, R. C.; Jones, T.; Richard, J.; Bower, R. G.; Ellis, R. S.; Swinbank, A. M.; Rigby, J. R.; Smail, Ian; Arribas, S.; Rodriguez-Zaurin, J.; hide

    2013-01-01

    We present Hubble Space Telescope/Wide Field Camera 3 narrow-band imaging of the Ha emission in a sample of eight gravitationally lensed galaxies at z = 1-1.5. The magnification caused by the foreground clusters enables us to obtain a median source plane spatial resolution of 360 pc, as well as providing magnifications in flux ranging from approximately 10× to approximately 50×. This enables us to identify resolved star-forming HII regions at this epoch and therefore study their Ha luminosity distributions for comparisons with equivalent samples at z approximately 2 and in the local Universe. We find evolution in the both luminosity and surface brightness of HII regions with redshift. The distribution of clump properties can be quantified with an HII region luminosity function, which can be fit by a power law with an exponential break at some cut-off, and we find that the cut-off evolves with redshift. We therefore conclude that 'clumpy' galaxies are seen at high redshift because of the evolution of the cut-off mass; the galaxies themselves follow similar scaling relations to those at z = 0, but their HII regions are larger and brighter and thus appear as clumps which dominate the morphology of the galaxy. A simple theoretical argument based on gas collapsing on scales of the Jeans mass in a marginally unstable disc shows that the clumpy morphologies of high-z galaxies are driven by the competing effects of higher gas fractions causing perturbations on larger scales, partially compensated by higher epicyclic frequencies which stabilize the disc.

  1. Spitzer Local Volume Legacy (LVL) Star-Forming Regions: Luminosity Functions

    NASA Astrophysics Data System (ADS)

    Cook, David O.; Dale, Daniel A.; Lee, Janice C.; LVL Team

    2015-01-01

    The conversion of gas into stars is one of the most fundamental processes in the universe, yet the effects of environmental conditions are poorly constrained. Observations of star-forming regions (young star clusters and HII regions) have shown evidence of a fractal pattern in their mass and luminosity distributions. The Mass Function (MF), and similarly the Luminosity Function (LF), of star-forming regions can be approximated as a power-law and is characterized by the power-law slope. A consistent slope of -2 has been observed across numerous galaxies, however, systematic deviations from this canonical slope have been measured across different environments. We present the LF slopes for 258 nearby galaxies in the Local Volume Legacy (LVL) sample utilizing tens of thousands of Hα- and FUV-selected sources. We test any relationships between LF slope and global galaxy properties to quantify the effect of environment on the star formation process. In addition, we combine the entire star-forming region sample in an attempt to characterize a previously proposed break in the HII region LF power-law at L˜38.6 erg/s.

  2. Molecular gas associated with IRAS 10361-5830

    NASA Astrophysics Data System (ADS)

    Vazzano, M. M.; Cappa, C. E.; Vasquez, J.; Rubio, M.; Romero, G. A.

    2014-10-01

    Aims: We analyze the distribution of the molecular gas and dust in the molecular clump linked to IRAS 10361-5830, located in the environs of the bubble-shaped Hii region Gum 31 in the Carina region, with the aim of determining the main parameters of the associated material and of investigating the evolutionary state of the young stellar objects identified there. Methods: Using the APEX telescope, we mapped the molecular emission in the J = 3-2 transition of three CO isotopologues, 12CO, 13CO and C18O, over a 1.´5 × 1.´5 region around the IRAS position. We also observed the high-density tracers CS and HCO+ toward the source. The cold- dust distribution was analyzed using submillimeter continuum data at 870 μm obtained with the APEX telescope. Complementary IR and radio data at different wavelengths were used to complete the study of the interstellar medium. Results: The molecular gas distribution reveals a cavity and a shell-like structure of ~0.32 pc in radius centered at the position of the IRAS source, with some young stellar objects projected onto the cavity. The total molecular mass in the shell and the mean H2volume density are ~40 M⊙ and ~(1-2) × 103 cm-3. The cold-dust counterpart of the molecular shell has been detected in the far-IR at 870 μm and in Herschel data at 350 μm. Weak extended emission at 24 μm from warm dust is projected onto the cavity, as well as weak radio continuum emission. Conclusions: A comparison of the distribution of cold and warm dust, and molecular and ionized gas allows us to conclude that a compact Hii region has developed in the molecular clump, indicating that this is an area of recent massive star formation. Probable exciting sources capable of creating the compact Hii region are investigated. The 2MASS source 10380461-5846233 (MSX G286.3773-00.2563) seems to be responsible for the formation of the Hii region. FITS files with datacubes corresponding to 12CO, 13CO, C180 maps are only available at the CDS via anonymous

  3. Star formation in the inner galaxy: A far-infrared and radio study of two H2 regions

    NASA Technical Reports Server (NTRS)

    Lester, D. F.; Dinerstein, H. L.; Werner, M. W.; Harvey, P. M.; Evans, N. J.; Brown, R. L.

    1985-01-01

    Far-infrared and radio continuum maps have been made of the central 6' of the inner-galaxy HII regions G30.8-0.0 (in the W43 complex) and G25.4-0.2, along with radio and molecular line measurements at selected positions. The purpose of this study is an effort to understand star formation in the molecular ring at 5 kpc in galactic radius. Measurements at several far infrared wavelengths allow the dust temperature structures and total far infrared fluxes to be determined. Comparison of the radio and infrared maps shows a close relationship between the ionized gas and the infrared-emitting material. There is evidence that parts of G30.8 are substantially affected by extinction, even at far-infrared wavelengths. Using radio recombination line and CO line data for G25.4-0.2, the distance ambiguity for this source is resolved. The large distance previously ascribed to the entire complex is found to apply to only one of the two main components. The confusion in distance determination is found to result from an extraordinary near-superposition of two bright HII regions. Using the revised distances of 4.3 kpc for G25.4SE and 12 kpc for G25.4NW, it is found that the latter, which is apparently the fainter of the two sources, is actually the more luminous. The ratio of total luminosity to ionizing luminosity is very similar to that of HII regions in the solar circle. Assuming a coeval population of ionizing stars, a normal initial mass function is indicated.

  4. Spitzer Follow-up of HST Observations of Star Formation in H II Regions

    NASA Astrophysics Data System (ADS)

    Hester, Jeff; Bally, John; Desch, Steve; Healy, Kevin; Snider, Keely

    2005-06-01

    Images of regions of star formation taken with HST have given us an extraordinary view of young stellar objects and their natal environments. These views differ tremendously between low-mass YSOs seen in regions of isolated low-mass star formation such as Taurus-Auriga, and the proplyds, EGGs, and other structures seen in regions of massive star formation. While YSOs in Taurus spend their adolescence buried in the dark interiors of molecular clouds, YSOs near massive stars quickly find themselves overrun by ionization fronts and exposed to the intense UV radiation from nearby massive stars. This difference in environment has a profound effect on the way in which the protoplanetary disk around a star evolves -- a fact that is of great importance to us, given the strength of the evidence suggesting that the Sun formed near a massive star. But HST while HST can inform us about the evolution of YSOs in HII region environments once they are overrun by ionization fronts, it cannot show us the birth of the stars themselves. These remain hidden in the dense molecular material beyond the ionized volumes of these regions. Only Spitzer can show us the properties of the YSOs that lie hidden in the dark shadows of HST images of HII regions, and only Spitzer can provide us with information about PDRs, warm dust, and other tracers of the interaction of massive stars with their surroundings. The combination of HST and Spitzer observations of star forming regions is far greater than the sum of its parts. If we are to build a complete picture of low-mass star formation and the evolution of disks near massive stars, we need to combine HST and Spitzer observations of the same regions. In this proposal we request time to obtain both IRAC and MIPS 24 micron images of each HII region that has been observed by HST, but has yet to be observed with Spitzer. Together with previous images obtained from the archives, this will comprise an indispensible data set for testing hypotheses about

  5. The Stellar Content of Intermediate-Mass Star-Forming Regions.

    NASA Astrophysics Data System (ADS)

    Lundquist, Michael; Kobulnicky, H.; Alexander, M.; Vargas Alvarez, C.; Arvidsson, K.; Kerton, C.

    2012-01-01

    In an effort to understand the factors that govern the transition from low- to high-mass star formation, we report near-infrared imaging and spectroscopy of stars within a sample of intermediate-mass star-forming regions (IMSFRs). Some IMSFRs appear to contain compact <1 pc embedded clusters at an early evolutionary stage similar to compact HII regions, but lacking the massive ionizing central star(s). The IMSFRs have photodissociation regions with diameters 1 pc powered by the equivalent of an early B star, but because all sources lack radio free-free emission, they must host a collection of less massive stars. These spectroscopic observations using FLAMINGOS on the Kitt Peak 4 m telescope, coupled with 2MASS and UKIDSS infrared imaging, identify which candidate IMSFRs host probable stellar clusters and address the nature of their most massive stellar constituents.

  6. The Density Structure of UCHII Regions: CS Observations

    NASA Astrophysics Data System (ADS)

    Butner, H. M.; Lauwers, T. L.

    2000-12-01

    Ultra-compact HII (UCHII) regions are sites of massive star formation. As yet, the physical conditions inside these regions are still poorly known. Submillimeter observations offer one way of probing the gas density and temperature. As part of an extensive study of the chemistry and physical conditions inside UCHII regions, we undertook a project to map several UCHII regions in CS. CS is an abundant molecule, and is an excellent density probe. Using the Submillimeter Telescope Observatory (SMTO), we are mapping ten UCHII regions in detail at a variety of CS transitions, including the CS 5-4, 7-6 and C34S 5-4 and 7-6 lines. The regions chosen also have far-infrared data and submm data available, so we will be able to compare the dust and gas properties. We report the first results of the CS mapping program for CS 5-4 and CS 7-6 lines. We compare our conclusions with other studies of these regions. T. L. Lauwers was supported by the University of Arizona/NASA Space Grant Undergraduate Research Internship Program.

  7. Star Clusters and Associations in the 30 Doradus Region: Tracing more than 25 Myr of Massive Star Formation in a Prototypical Starburst

    NASA Astrophysics Data System (ADS)

    Sabbi, Elena

    2015-08-01

    30 Doradus (a.k.a. Tarantula Nebula) is the closest extragalactic giant HII region. By virtue of its privileged position in the Large Magellanic Cloud 30 Doradus is the only starburst that can be studied down to the sub-solar mass regime.We will discuss the stellar content, the clustering properties, and the temporal and spatial impact of stellar feedback on the lifecycle of stars and clusters in an environment that resembles the extreme conditions found in the starburst knots observed in interacting galaxies in the Local Universe and in the young galaxies at high redshift.

  8. An accretion disks in the high-mass star forming region IRA 23151+5912

    NASA Astrophysics Data System (ADS)

    Migenes, Victor; Rodríguez-Esnard, T.; Trinidad, M. A.

    2014-01-01

    We present observations of radio continuum emission at 1.3 and 3.6 cm and H2O masers toward the high-mass star-forming regions IRA 23151+5912 carried out with the VLA-EVLA. We detected one continuum source at 1.3 cm and 13 water maser spots which are distributed in three groups aligned along the northeast-southwest direction. Our results suggest that the 1.3 cm emission is consistent with an HC HII region, probably with an embedded zero-age main sequence star of type B2. In particular, we find that this radio continuum source is probably associated with a circumstellar disk of about 68 AU, as traced by water masers. Furthermore, the masers of the second group are probably describing another circumstellar disk of about 86 AU, whose central protostar is still undetected. We discuss this results in the light of more recent high-resolution observations.

  9. Evolution and saturation of Autowaves in photodissociation regions

    NASA Astrophysics Data System (ADS)

    Krasnobaev, K. V.; Tagirova, R. R.; Arafailov, S. I.; Kotova, G. Yu.

    2016-07-01

    The propagation of plane, cylindrical, and spherical waves in a thermally unstable gas-dust medium has been simulated numerically. As applied to the photodissociation regions near O and B stars, we take into account the interaction of ultraviolet radiation with dust grains and large polycyclic aromatic hydrocarbon molecules as well as the gas cooling through the excitation of CII ions and OI atoms and the deexcitation of rotational levels of CO molecules. The instability regions have been determined. The perturbation growth times corresponding to them are ~103-105 yr. We show that wave breaking occurs irrespective of the geometry of motion, while a perturbation in the form of a single pulse gives rise to a sequence of shock waves. The post-shock gas velocity is approximately 0.1-0.5 of the sound velocity, so that the autowaves can contribute noticeably to the observed velocity dispersion of the gas near the boundaries of HII regions. Two-dimensional simulations suggest that the presence of multiple shocks in a thermally unstable medium can accelerate significantly the destruction of preexisting isolated condensations.

  10. New Eruptive Variable in the Massive Star-Forming Region Associated with IRAS 18507+0121 Source

    NASA Astrophysics Data System (ADS)

    Nikoghosyan, E. H.; Azatyan, N. M.; Khachatryan, K. G.

    2017-07-01

    We report the discovery of a strong outburst of the embedded young stellar object (YSO), namely UKIDSS-J185318.36+012454.5, located in the star-forming region associated with IRAS 18507+0121 source and GAL 034.4+00.23 HII region. According to the near and mid-infrared colors and spectral energy distribution (SED), we classify the object as an intermediate mass young stellar object (YSO) with Class 0/I evolution stage. The outburst occurred in the period of 2004-2006. The amplitude of brightness is at least Ks = 5.0 mag. The summation of the photometric and spectral data does not allow to classify UKIDSS-J185318.36+012454.5 as FUor or EXor. We can consider it as an eruptive variable with mixed characteristics or MNor type object.

  11. Spectroscopy of planetary nebulae in the region of Canis Major

    NASA Astrophysics Data System (ADS)

    Kniazev, A. Yu.

    2012-11-01

    We present the results of a pilot project of spectroscopic observations for planetary nebulae (PNe) and PN candidates in Canis Major, a sky region where the remnant of a disrupted dwarf galaxy cannibalized by the Milky Way may be located. The spectra of seven objects were taken while testing the SALT spectrograph (South African Astronomical Observatory). All elemental abundances have been obtained by the T e method, where the electron temperature is calculated directly using the measured weak auroral [OIII] λ 4363 Å and/or [NII] λ 5755 Å lines. We have measured the intensities of all the detected emission lines and determined the abundances of oxygen and several other elements (N, Ne, S, Cl, C, and He) in all PNe. The radial velocity for one PN has been measured for the first time and the velocities for all of the remaining PNe have been measured with a considerably better accuracy than that of the previously published ones. The elemental abundances for three PNe have been calculated for the first time and the accuracies of determining the abundances for three others have been improved. The measured heavy-element abundance ratios (S/O, Ne/O, Cl/O) are in good agreement with their typical values for HII regions. Among the PNe studied, ESO 428-05 is the first and so far the most likely candidate for belonging to the remnants of a possible dwarf galaxy disrupted by the tidal interaction with the Milky Way.

  12. Distribution of water in the G327.3-0.6 massive star-forming region

    NASA Astrophysics Data System (ADS)

    Leurini, S.; Herpin, F.; van der Tak, F.; Wyrowski, F.; Herczeg, G. J.; van Dishoeck, E. F.

    2017-06-01

    Aims: Following our past study of the distribution of warm gas in the G327.3-0.6 massive star-forming region, we aim here at characterizing the large-scale distribution of water in this active region of massive star formation made of individual objects in different evolutionary phases. We investigate possible variations of the water abundance as a function of evolution. Methods: We present Herschel/PACS (4'× 4') continuum maps at 89 and179 μm encompassing the whole region (Hii region and the infrared dark cloud, IRDC) and an APEX/SABOCA (2'× 2') map at 350 μm of the IRDC. New spectral Herschel/HIFI maps toward the IRDC region covering the low-energy water lines at 987 and 1113 GHz (and their H218O counterparts) are also presented and combined with HIFI pointed observations toward the G327 hot core region. We infer the physical properties of the gas through optical depth analysis and radiative transfer modeling of the HIFI lines. Results: The distribution of the continuum emission at 89 and 179 μm follows the thermal continuum emission observed at longer wavelengths, with a peak at the position of the hot core and a secondary peak in the Hii region, and an arch-like layer of hot gas west of this Hii region. The same morphology is observed in the p-H2O 111-000 line, in absorption toward all submillimeter dust condensations. Optical depths of approximately 80 and 15 are estimated and correspond to column densities of 1015 and 2 × 1014 cm-2, respectively, for the hot core and IRDC position. These values indicate an abundance of water relative to H2 of 3 × 10-8 toward the hot core, while the abundance of water does not change along the IRDC with values close to some 10-8. Infall (over at least 20″) is detected toward the hot core position with a rate of 1-1.3 × 10-2M⊙ /yr, high enough to overcome the radiation pressure that is due to the stellar luminosity. The source structure of the hot core region appears complex, with a cold outer gas envelope in

  13. Radial metallicity gradients in spiral galaxies from H II regions and planetary nebulae: probing galactic chemical evolution

    NASA Astrophysics Data System (ADS)

    Stanghellini, Letizia

    2015-08-01

    Radial metallicity gradients, typically observed in spiral galaxies, are excellent constraints for chemical evolution models. The contemporary studies of the two stellar populations, whose progenitors have formed at different times, yield to the chemical and time constraining of the models. In this context, planetary nebula and HII region analysis proved to be ideal two-epochs test populations. We present an assortment of galaxies whose oxygen abundances have been determined both with weak- and strong-line methods, and whose radial metallicity gradients and their evolution in time have disclosed very interesting correlations with the galaxy characteristics. New results from our Gemini/GMOS observations, and a review of the best literature data, set the stage for a better understanding of spiral galaxy evolution.

  14. Herschel far-infrared observations of the Carina Nebula complex - The embedded young stellar and protostellar population

    NASA Astrophysics Data System (ADS)

    Gaczkowski, Benjamin; Preibisch, Thomas; Ratzka, Thorsten; Roccatagliata, Veronica; Ohlendorf, Henrike; Pekruhl, Stephanie

    2013-07-01

    At a distance of 2.3 kpc, the Carina Nebula is the nearest southern region with a large enough massive stellar population to sample the top of the IMF and displays all phenomena of massive star formation. We have performed a 9 square-degree Herschel far-infrared survey of the Carina Nebula complex (CNC) which revealed, for the first time, the very complex and filamentary small-scale structure of the dense clouds. We discovered 642 objects that are independently detected as point-like sources in at least two of the five Herschel bands. About 75% of these are Class 0 protostars with masses between about one and ten solar masses estimated from radiative transfer modeling. Taking the observational limits into account and extrapolating the observed number of Herschel-detected protostars over the stellar initial mass function suggests that the star formation rate of the CNC is about 0.017 solar masses per year. The spatial distribution of the Herschel young stellar objects (YSO) candidates is highly inhomogeneous and does not follow the distribution of cloud mass. Rather, most Herschel YSO candidates are found at the irradiated edges of clouds and pillars. The currently ongoing star formation process forms only low-mass and intermediate-mass stars, but no massive stars. The characteristic spatial configuration of the YSOs provides support to the picture that the formation of this latest stellar generation is triggered by the advancing ionization fronts. Around the bubble-shaped HII region Gum 31 (containing the young stellar cluster NGC 3324) in the north-western part of the CNC we identified 752 candidate YSOs from Spitzer, WISE, and Herschel data and analyzed their spectral energy distributions. Their location in the rim of the bubble is suggestive of their being triggered by a 'collect and collapse' scenario, which agrees well with the observed parameters of the region which we obtained from density and temperature maps from our Herschel data.

  15. Fotometria WHBY |o lll|/HB de Regiones H 11 Y la HISTORIA de la Formacion ESTELAR Reciente EN la PEQUENA NUBE de Magallanes

    NASA Astrophysics Data System (ADS)

    Copetti, M. V. F.; Dottori, H. A.

    1987-05-01

    El ancho equivalente WHβ de la linea de Hβ en emisión y la razón [0 III]/Hβ del par λλ4959, 50 7 A del [0111], fueron medidos en 23 regiones HII de la Peque˜a Nube de Magallanes, por medio de la fotometría fotoeléctrica a través de un sistema de tres filtros interferenciales: dos Hβ , con bandas pasantes de 100 y 30 A, y un [0111] centrado en 5000 A y con banda pasante de 50 A. Las observaciones fueron realizadas con los telescopios de 1.60-m y 0.60-m del Laboratorio Nacional de Astrofísica, Brasópolis, Brasil. Fueron escogidos diafragmas suficientemente grandes para captar la radiación integrada de cada región HII. Las medidas fueron calibradas por comparación a un conjunto de nebulosas planetarias con flujos absolutos bien definidos. A través de la comparación entre los datos observacionales y modelos evolutivos de WHβ y [0 III] /Hβ (Copetti et al.1986', Astr. and Ap., 156, 111), las edades de las regiones HIl fueron estimadas. Basada en la distribución espacial de las edades de regiones HIl, la historia de la formación estelar reciente en la Pequeña Nube de Magallanes es analizada. La similitud de las medidas de WH&beta y [OIII]/WHβ entre las regiones H II observadas sugiere que hubo una explosión de formación estelar a 4±1 x106 años en la Pequeña Nube de Magallanes. (Parcialmente financiado por CNPq).

  16. Carbon gas in SMC low-metallicity star-forming regions

    NASA Astrophysics Data System (ADS)

    Requena-Torres, M. A.; Israel, F. P.; Okada, Y.; Güsten, R.; Stutzki, J.; Risacher, C.; Simon, R.; Zinnecker, H.

    2016-05-01

    This paper presents [ CII ], [ CI ] and CO emission line maps of the star-forming regions N 66, N 25+N 26, and N 88 in the metal-poor Local Group dwarf galaxy SMC. The spatial and velocity structure of the large HII region N 66 reveals an expanding ring of shocked molecular gas centered on the exciting star cluster NGC 346, whereas a more distant dense molecular cloud is being eroded by UV radiation from the same cluster. In the N 25+N 26 and N 88 maps, diffuse [ CII ] emission at a relatively low surface brightness extends well beyond the compact boundaries of the bright emission associated with the HII regions. In all regions, the distribution of this bright [ CII ] emission and the less prominent [ CI ] emission closely follows the outline of the CO complexes, but the intensity of the [ CII ] and [ CI ] emission is generally anticorrelated, which can be understood by the action of photodissociation and photoionization processes. Notwithstanding the overall similarity of CO and [ CII ] maps, the intensity ratio of these lines varies significantly, mostly due to changes in CO brightness. [ CII ] emission line profiles are up to 50% wider in velocity than corresponding CO profiles. A radiative transfer analysis shows that the [ CII ] line is the dominant tracer of (CO-dark) molecular hydrogen in the SMC. CO emission traces only a minor fraction of the total amount of gas. The similarity of the spatial distribution and line profile shape, and the dominance of molecular gas associated with [ CII ] rather than CO emission imply that in the low-metallicity environment of the SMC the small amount of dense molecular gas traced by CO is embedded in the much more extended molecular gas traced only by [ CII ] emission. The contribution from neutral atomic and ionized hydrogen zones is negligible in the star-forming regions observed. The reduced datacubes (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via

  17. Spatial distribution of star formation related to ionized regions throughout the inner Galactic plane

    NASA Astrophysics Data System (ADS)

    Palmeirim, P.; Zavagno, A.; Elia, D.; Moore, T. J. T.; Whitworth, A.; Tremblin, P.; Traficante, A.; Merello, M.; Russeil, D.; Pezzuto, S.; Cambrésy, L.; Baldeschi, A.; Bandieramonte, M.; Becciani, U.; Benedettini, M.; Buemi, C.; Bufano, F.; Bulpitt, A.; Butora, R.; Carey, D.; Costa, A.; Deharveng, L.; Di Giorgio, A.; Eden, D.; Hajnal, A.; Hoare, M.; Kacsuk, P.; Leto, P.; Marsh, K.; Mège, P.; Molinari, S.; Molinaro, M.; Noriega-Crespo, A.; Schisano, E.; Sciacca, E.; Trigilio, C.; Umana, G.; Vitello, F.

    2017-09-01

    We present a comprehensive statistical analysis of star-forming objects located in the vicinities of 1360 bubble structures throughout the Galactic plane and their local environments. The compilation of 70 000 star-forming sources, found in the proximity of the ionized (Hii) regions and detected in both Hi-GAL and GLIMPSE surveys, provided a broad overview of the different evolutionary stages of star-formation in bubbles, from prestellar objects to more evolved young stellar objects (YSOs). Surface density maps of star-forming objects clearly reveal an evolutionary trend where more evolved star-forming objects (Class II YSO candidates) are found spatially located near the center, while younger star-forming objects are found at the edge of the bubbles. We derived dynamic ages for a subsample of 182 H ii regions for which kinematic distances and radio continuum flux measurements were available. We detect approximately 80% more star-forming sources per unit area in the direction of bubbles than in the surrounding fields. We estimate the clump formation efficiency (CFE) of Hi-GAL clumps in the direction of the shell of the bubbles to be 15%, around twice the value of the CFE in fields that are not affected by feedback effects. We find that the higher values of CFE are mostly due to the higher CFE of protostellar clumps, in particular in younger bubbles, whose density of the bubble shells is higher. We argue that the formation rate from prestellar to protostellar phase is probably higher during the early stages of the (H ii ) bubble expansion. Furthermore, we also find a higher fraction of massive YSOs (MYSOs) in bubbles at the early stages of expansion (<2 Myr) than older bubbles. Evaluation of the fragmentation time inside the shell of bubbles advocates the preexistence of clumps in the medium before the bubble expansion in order to explain the formation of MYSOs in the youngest H ii regions (<1 Myr), as supported by numerical simulations. Approximately 23% of the Hi

  18. Molecular Outflows in Massive Star Forming Regions

    NASA Astrophysics Data System (ADS)

    Cunningham, Nichol

    2015-11-01

    This thesis presents millimetre continuum and molecular line observations exploring the properties of molecular outflows towards massive star forming regions. Massive stars produce some of the most energetic phenomena in the Galaxy, yet we still do not have a comprehensive understanding of how they actually form. Outflows are known to play a key role in this formation process and their properties, particularly how they change depending on the mass, luminosity and evolution of the driving source can shed light on how massive stars actually form. This thesis presents observations at both high (SMA 3 arcsecond) and low (JCMT 15 arcsecond) spatial resolution of the known jet/outflow tracers, SiO and 12CO, towards a sample massive star forming region drawn from the RMS survey. Furthermore, the presence of infall signatures is explored through observations of HCO+ and H13CO+, and the hot core nature of the regions is probed using tracers such as CH3CN, HC3N and CH3OH. SiO is detected towards approximately 50% of the massive young stellar objects and HII regions in the JCMT sample. The detection of SiO appears to be linked to the age of the RMS source, with the likely younger sources showing a stronger dependence with SiO. The presence of SiO also appears to be linked to the CO velocity, with SiO more efficiently tracing sources with higher velocity dispersions. In the MOPRA observations towards a sample of 33 RMS sources, CH3CN is detected towards 66% of the sources, with the redder likely younger sources having the largest rotational temperatures. This thesis presents the first interferometric SiO (5-4) and 12CO (2-1) observations, taken with the SMA, towards the massive star forming region G203.3166/NGC 2264-C. In this intermediate/massive star forming cluster, SiO is again tracing the youngest sources. Both the SiO and 12CO emission trace two bipolar, high velocity outflows towards the mm brightest, IR-dark, likely youngest sources in this reg! ion. In contrast the IR

  19. Structure of Bubbles in the South-East region of the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Oddone, M. A.; Ambrocio-Cruz, P.; LeCoarer, E.; Goldes, G. V.

    2014-10-01

    In this work we report the kinematical results of the structure located in the South-East region of the Large Magellanic Cloud, the Supershell LMC 9. The observations have been carried out in the frame of a Hα survey of the Magellanic Clouds and the Milky Way, carried out at ESO with a 36cm diameter telescope, equipped with a focal reducer, a scanning Fabry-Perot interferometer and a photon counting camera. The Supershell LMC 9 is composed of four giant shells DEM L 164 and DEM L 165, DEM L 208, DEM L 221, and several HII regions being the most notorious DEM L 202, DEM L206 and DEM L 207. By means of energy balance we determine the characteristics parameters of these structures (superficial brightness, electronic density, emission measure, mass, luminosity, ambient density, age), that would allow us to distinguish which is the origin (stellar wind, supernova explosion or other mechanism) of the different bubbles that compose the Supershell LMC 9. In this way we try to discern if the studied objects have kinematically some identity as an ensemble, or if they are relatively isolated objects over the diffuse general background to which they belong.

  20. A distância e o conteúdo estelar da região HII gigante G333.1-0.4 - vínculos para a taxa de formação estelar da galáxia

    NASA Astrophysics Data System (ADS)

    Figuerêdo, E.; Damineli, A.; Blum, R.; Conti, P.

    2003-08-01

    Neste trabalho apresentamos imagens de alta resolução angular da região HII gigante G333.1-0.4 obtidas através dos filtros J, H e K no telescópio de 4-m do CTIO. Este trabalho faz parte de um estudo de regiões HII gigantes no infravermelho próximo que tem por objetivo estudar a natureza da formação de estrelas massivas e traçar a estrutura espiral de nossa galáxia. Nossa determinação da distância é baseada no método da paralaxe espectroscópica de estrelas OB localizadas na seqüência principal de idade zero (ZAMS) do Diagrama HR. No caso de G333.1-0.4, a magnitude aparente das estrelas localizadas na ZAMS indica que a distância não pode ser maior do que o limite inferior determinado por técnica rádio (2,8 kpc). Resultados semelhantes foram encontrados para regiões estudadas anteriormente, reforçando a idéia de que a taxa de formação estelar na Via Láctea é menor do que o determinado a partir de dados rádio. Nossos resultados mais recentes sobre o conteúdo estelar de G333.1-0.4 revelaram vários objetos que possuem cores bastante avermelhadas (H-K > 2,0). Nós identificamos estes objetos usando os diagramas cor-cor e cor-magnitude dos aglomerados. Estes objetos apresentam um forte excesso em emissão na banda K e possivelmente se tratam de estrelas do tipo OB envolvidas por um disco/envelope circumestelar espesso. O estudo da função de massa inical desta região, em conjunto com resultados de nossos trabalhos anteriores, aponta para uma IMF independente da posição galática. A contagem de estrelas nos fornece um valor para o número de fótons no contínuo de Lyman que corrobora com a afirmação de que G333.1-0.4 se encontra mais próxima da menor distância determinada por rádio.

  1. Chaos Region

    NASA Image and Video Library

    2015-09-10

    In the center of this 300-mile (470-kilometer) wide image of Pluto from NASA's New Horizons spacecraft is a large region of jumbled, broken terrain on the northwestern edge of the vast, icy plain informally called Sputnik Planum, to the right. The smallest visible features are 0.5 miles (0.8 kilometers) in size. This image was taken as New Horizons flew past Pluto on July 14, 2015, from a distance of 50,000 miles (80,000 kilometers). http://photojournal.jpl.nasa.gov/catalog/PIA19934

  2. The Physical and Kinematic Structure of the DR 21 (OH) Star Formation Region

    NASA Astrophysics Data System (ADS)

    Kaleida, C. C.; Mangum, J. G.

    2003-12-01

    The DR 21 (OH) region is an area of dense molecular gas, which appears to contain a cluster of newly forming stars. DR 21 (OH) lies approximately 2.6 pc to the north of the DR 21 HII region, the strongest and best studied 5 GHz source in the Cygnus X molecular cloud complex (Mangum, Wootten, & Mundy 1992; Downes & Rinehart 1966; Harris 1973). Measurements of the H2CO, CS, and CO emission toward the DR 21 (OH) molecular cloud were made by Mangum using the VLA, the OVRO Millimeter Array, and the Caltech Submillimeter Observatory. CS and H2CO molecular emission from this region was examined to determine kinetic temperature and spatial density structure, while CS and CO emission was utilized to probe the outflow properties of the young stellar objects. For the DR 21 (OH) main region a third line component has been discerned in addition to the two previously detected line components, dubbed MM1 and MM2 (Mangum, Wootten, & Mundy 1992). This third component constitutes a newly resolved broad wing component indicating an outflow. Careful inspection of the CO and CS emission reveals what appears to be a bipolar outflow that is most likely associated with the MM1 source. Calibrated values for the radiative temperature of each emission line were input into a Large Velocity Gradient (LVG) model, which models the source radiative transfer mechanisms to estimate spatial density, kinetic temperature, and molecular abundance. The densities determined from LVG modeling of the wing component were used along with spectral observations of its spatial extent to determine the flux density of the outflow. Information gained from the analysis of the kinetic temperature, spatial density, and outflow structure has been used to derive the history of the star formation process in this region. Financial support provided by the NSF REU Program.

  3. Photodissociation Regions

    NASA Technical Reports Server (NTRS)

    Hollenbach, David J.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    The interstellar medium of galaxies is the reservoir out of which stars are born and into which stars inject newly created elements as they age. The physical properties of the interstellar medium are governed in part by the radiation emitted by these stars. Far-ultraviolet (6 eV< hNu < 13.6 eV) photons from massive stars dominate the heating and influence the chemistry of the neutral atomic gas and much of the molecular gas in galaxies. Predominantly neutral regions of the interstellar medium in which the heating and chemistry are regulated by far ultraviolet photons are termed Photodissociation Regions (PDRs). These regions are the origin of most of the non-stellar infrared (IR) and the millimeter and submillimeter CO emission from galaxies. The importance of PDRs has become increasingly apparent with the advances in IR and submillimeter astronomy. The IR emission from PDRs includes fine structure lines of C, C(+) and O; rovibrational lines of H2; rotational lines of CO; broad mid-IR features of polycyclic aromatic hydrocarbons; and a luminous underlying IR continuum from interstellar dust. The transition of H to H2 and C(+) to CO occurs within PDRs. Comparison of observations with theoretical models of PDRs enables one to determine the density and temperature structure, the elemental abundances, the level of ionization, and the radiation field. PDR models have been applied to interstellar clouds near massive stars, planetary nebulae, red giant outflows, photoevaporating planetary disks around newly formed stars, diffuse clouds, the neutral intercloud medium, and molecular clouds in the interstellar radiation field-in summary, much of the interstellar medium in galaxies. Theoretical PDR models explain the observed correlations of the [CII] 158, micrometers with the CO J=1-0 emission, the CO J=1-0 luminosity with the interstellar molecular mass, and the [CII] 158 micrometers plus [OI] 63 micrometers luminosity with the IR continuum luminosity. On a more global

  4. Gas versus solid-phase deuterated chemistry: HDCO and D2CO in massive star-forming regions

    NASA Astrophysics Data System (ADS)

    Zahorecz, S.; Jimenez-Serra, I.; Testi, L.; Immer, K.; Fontani, F.; Caselli, P.; Wang, K.; Toth, L. V.

    2017-06-01

    Context. The formation of deuterated molecules is favoured at low temperatures and high densities. Therefore, the deuteration fraction (Dfrac) is expected to be enhanced in cold, dense prestellar cores and to decrease after protostellar birth. Previous studies have shown that the deuterated forms of species such as N2H+ (formed in the gas phase) and CH3OH (formed on grain surfaces) can be used as evolutionary indicators and to constrain their dominant formation processes and timescales. Aims: Formaldehyde (H2CO) and its deuterated forms can be produced both in the gas phase and on grain surfaces. However, the relative importance of these two chemical pathways is unclear. Comparison of the deuteration fraction of H2CO with respect to that of N2H+, NH3, and CH3OH can help us to understand its formation processes and timescales. Methods: With the new SEPIA Band 5 receiver on APEX, we have observed the J = 3 → 2 rotational lines of HDCO and D2CO at 193 GHz and 175 GHz toward three massive star-forming regions hosting objects at different evolutionary stages: two high-mass starless cores (HMSC), two high-mass protostellar objects (HMPOs), and one ultracompact HII region (UC HII). By using previously obtained H2CO J = 3 → 2 data, the deuteration fractions HDCO/H2CO and D2CO/HDCO are estimated. Results: Our observations show that singly deuterated H2CO is detected toward all sources and that the deuteration fraction of H2CO increases from the HMSC to the HMPO phase and then sharply decreases in the latest evolutionary stage (UCHII). The doubly deuterated form of H2CO is detected only in the earlier evolutionary stages, with D2CO/H2CO showing a pattern that is qualitatively consistent with the pattern of HDCO/H2CO, within current uncertainties. Conclusions: Our initial results show that H2CO may display a similar Dfrac pattern as that of CH3OH in massive young stellar objects. This finding suggests that solid-state reactions dominate its formation.

  5. Deep optical survey of the stellar content of Sh2-311 region

    NASA Astrophysics Data System (ADS)

    Yadav, Ram Kesh; Pandey, A. K.; Sharma, Saurabh; Jose, J.; Ogura, K.; Kobayashi, N.; Samal, M. R.; Eswaraiah, C.; Chandola, H. C.

    2015-01-01

    The stellar content in and around Sh2-311 region have been studied using the deep optical observations as well as near-infrared (NIR) data from 2MASS. The region contains three clusters, viz. NGC 2467, Haffner 18 and Haffner 19. We have made an attempt to distinguish the stellar content of these individual regions as well as to re-determine their fundamental parameters such as distance, reddening, age, onto the basis of a new and more extended optical and infrared photometric data set. NGC 2467 and Haffner 19 are found to be located in the Perseus arm at the distances of 5.0 ± 0.4 kpc and 5.7 ± 0.4 kpc, respectively, whereas Haffner 18 is located at the distance of 11.2 ± 1.0 kpc. The clusters NGC 2467 and Haffner 19 might have formed from the same molecular cloud, whereas the cluster Haffner 18 is located in the outer galactic arm, i.e. the Norma-Cygnus arm. We identify 8 class II young stellar objects (YSOs) using the NIR (J-H)/(H-K) two colour diagram. We have estimated the age and mass of the YSOs identified in the present work and those by Snider et al. (2009) using the V/(V-I) colour-magnitude diagram. The estimated ages and mass range of the majority of the YSOs are ≲1 Myr and ∼0.4-3.5 M⊙, respectively, indicating that these sources could be T-Tauri stars or their siblings. Spatial distribution of the YSOs shows that some of the YSOs are distributed around the HII region Sh2-311, suggesting a triggered star formation at its periphery.

  6. Uncovering the monster stars in W49: the most luminous star-forming region in the Milky Way

    NASA Astrophysics Data System (ADS)

    Wu, Shiwei; Bik, Arjan; Henning, Thomas; Pasquali, Anna; Brandner, Wolfgang; Stolte, Andrea

    2015-08-01

    As a part of the LOBSTAR project (Luci OBservations of STARburst regions), which aims at understanding the stellar content of some of the most massive star-forming regions, we present our result on the high-mass stellar content of W49. K-band spectra of the candidate massive stars from VLT/ISAAC and LBT/LUCI provide us with reliable spectral types of dozens of massive stars in this HII region.The first results show that this region hosts several of the most massive stars in our galaxy. Two most brightest stars, one in the core of the central cluster and one in W49 South, were identified as very massive stars (M > 100 M⊙). Their K-band spectra exhibit strong stellar wind features, and they are classified as O2-3.5If* supergiant stars. After comparison to the Geneva evolutionary models, the mass range of W49nr1 was estimated to be between 100 M⊙ and 180 M⊙. Additionally we find 12 O stars with spectral types between O7V and O3V and masses from 25 M⊙ to 125 M⊙, respectively.These results allow us to derive the fundamental parameters of the cluster (mass, age) as well as the total energy output in the form of ionising photons. This will enable us to study the feedback effects of this extreme star forming region in great detail. To our surprise, two young stellar objects with infrared excess feature showing CO emission lines in their spectra are identified. This suggests that circumstellar disks can survive even in this extreme environment. Finally the spatial distribution of the massive stars is analysed to discuss the star formation history and identify potential runaway stars. The extreme properties of this region makes it a good template for more extreme star formation outside our galaxy.

  7. Karl G. Jansky VLA 3.6 cm Continuum and RRL Observations of the Galactic Massive Star Forming Region W49A

    NASA Astrophysics Data System (ADS)

    De Pree, Christopher G.; Wilner, David J.; Galvan-Madrid, Roberto; Goss, Miller; Klessen, Ralf; Mac Low, Mordecai-Mark; Peters, Thomas; Amason, Charlee

    2016-01-01

    We are using the VLA to make a multi-configuration study at 3.6 cm of the massive star forming region W49A. Using new observations from 2015, we have imaged W49A in the A, B, and D configurations in 3.6 cm continuum and H92α and H93α recombination line emission. We present initial continuum images, and selected line spectra of individual sources. This study is part of an ongoing campaign to search for variability in ultracompact HII regions, as predicted by models of unsteady accretion flows. Such variability has been detected in systematic searches of sources in the crowded Sgr B2 Main and North regions (De Pree et al., 2014, 2015). Deep VLA continuum and line observations were first made of W49A in 1993-94 in the B, C, and D configurations, and we will discuss preliminary comparisons of the new data with these 1993-94 archival data.

  8. Returning "Region" to World Regional Geography

    ERIC Educational Resources Information Center

    Rees, Peter W.; Legates, Margaret

    2013-01-01

    World regional geography textbooks rarely focus on the process of region formation, despite frequent calls to reincorporate a regional approach to teaching global geography. An instructional strategy using problem-based learning in a small honors section of a large world regional geography course is described. Using a hypothetical scenario…

  9. Ionospheric research. [E region, F region, D region

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Progress is reported in the following areas: D-region theory; E and F-region; wave propagation; mass spectrometer measurements; and atmospheric reactions. Various supporting operations are included: design and construction of instrumentation; and programming.

  10. Regional Sustainable Environmental Management

    EPA Science Inventory

    Regional sustainable environmental management is an interdisciplinary effort to develop a sufficient understanding of the interactions between ecosystems, the economy, law, and technology to formulate effective long-term management strategies on a regional scale. Regional sustai...

  11. Regional Sustainable Environmental Management

    EPA Science Inventory

    Regional sustainable environmental management is an interdisciplinary effort to develop a sufficient understanding of the interactions between ecosystems, the economy, law, and technology to formulate effective long-term management strategies on a regional scale. Regional sustai...

  12. VLA 7-mm Observations of Massive Star-forming Regions

    NASA Astrophysics Data System (ADS)

    Linz, Hendrik; Hofner, Peter; Araya, Esteban; Stecklum, Bringfried

    2003-07-01

    The early stages during the formation of massive stars are deeply enshrouded due to the presence of dense and dusty natal material. This prevents observations in the optical and often also in the near-infrared. The emission of the star-forming regions peaks in the far-infrared and sub-mm regime, but at these wavelengths, single-dish observations are restricted in spatial resolution and can give only upper limits on the energetics of the objects of interest. Interferometry at mm wavelengths is one appropriate technique to overcome these limitations. We have started an extensive programme to observe pre-selected massive star-forming regions. Our tool is the VLA and its 7-mm receiver system. The VLA can be operated in several antenna configurations delivering resolutions from 1.5 arcsec down to 0.05 arcsec, which is superior to other current mm-interferometers. Sub-arcsec resolution is strongly needed to disentangle the often crowded regions of high-mass star formation and to clearly separate our objects of interest from the adjacent ultracompact HII regions. At 7 mm we are on the save ground of the Rayleigh-Jeans limit even for emission of cold dust (a fact that is not always true for observations at smaller wavelengths). Almost all circumstellar density configurations are optically thin at 7 mm, thus, the observations will trace the total dust content. However, at 7 mm also the free-free emission from ionised gas (caused by the UV emission of the young massive stars) can contribute to the observed signal. Therefore, we have to identify and remove these "parasitic" constituents by extrapolating interferometric data obtained at cm-wavelengths. The targets are either taken from the list of Molinari (Molinari et al. 2000, A&A, 355, 617) or are well-known massive star-forming complexes, for which we have already acquired additional data at other wavelengths. We have started with observations at lower and medium resolution (1.5 - 0.5 arcsec) to distinguish candidates for

  13. Guidance and control of HOPE (H-II orbiting plane)

    NASA Astrophysics Data System (ADS)

    Mineno, Hitoshi; Suzuki, Takahiro; Takizawa, Yoshisada

    The National Space Development Agency of Japan (NASDA) has been studying HOPE. Guidance and control technology is one of the most critical technologies to realize HOPE. Studies on guidance and control of HOPE have been done focused on system design and management, navigation, guidance and control, and onboard equipment. The reference configuration and the algorithm of guidance and control system are almost fixed by navigation analyses. We show that the flight path of HOPE can be realized by guidance analyses. A trial model of GCC (Guidance Control Computer), GPSR (GPS Receiver) and MLS (Microwave Landing System) receiver are currently being developed. Several experiments are planned. The MLS flight experiment is explained by an example.

  14. Sulfur-bearing molecules observed in the massive star-forming regions, DR21(OH) and G33.92+0.11

    NASA Astrophysics Data System (ADS)

    Minh, Y. C.

    2016-07-01

    Recent high sensitive and high angular resolution observations are providing unprecedented amount of chemical data, especially, on the massive star-forming regions. It will greatly extend our understandings on the complicated star formation process, if we can digest those huge amount of information. We discuss here on the properties of the sulfurbearing species observed with high angular resolutions toward two massive star-forming regions, DR21(OH) and G33.92+0.11. H2S may not exist as a solid form in the grain mantles, but OCS is believed to be one of major solid sulfur species, as suggested before. In addition, the bipolar-like outflow of the H2CS emission observed in DR21(OH) may suggest that H2CS is also one of solid sulfur species on the grain mantles. Depending on the chemical environment, the competition between hydrogenation and oxidization on the grain surface may lead to formation of specific solid forms to dominate, which could be either H2CS or OCS. SO and SO2 are often observed to be associated with ionized gas, such as the UC HII regions. These species seem to be formed in the high temperature turbulent gas in a later stage of star formation after the hot core phase. Fractional abundances of these sulfur-bearing species appear to be consistent to a certain extent in several star-forming regions. The physical and chemical evolution of massive star formation seems to pass through very similar stages in most star-forming regions. Consequently, it may indicate that there exists a consistent and coherent pattern of processes experienced by the massive star formation, in spite of the large variations in small scale locational differences.

  15. Formulation and characterization of a liquid crystalline hexagonal mesophase region of phosphatidylcholine, sorbitan monooleate, and tocopherol acetate for sustained delivery of leuprolide acetate.

    PubMed

    Báez-Santos, Yahira M; Otte, Andrew; Mun, Ellina A; Soh, Bong-Kwan; Song, Chang-Geun; Lee, Young-Nam; Park, Kinam

    2016-11-30

    Although liquid crystal (LC) systems have been studied before, their utility in drug delivery applications has not been explored in depth. This study examined the development of a 1-month sustained release formulation of leuprolide acetate using an in situ-forming LC matrix. The phase progression upon water absorption was tested through construction of ternary phase diagrams of phosphatidylcholine, sorbitan monooleate, and tocopherol acetate (TA) at increasing water content. Small angle X-ray scattering revealed the presence of lamellar and hexagonal mesophases. The physicochemical characteristics and in vitro drug release were evaluated as a function of the ternary component ratio and its resultant phase behavior. Formulations with increased water uptake capacity displayed greater drug release and enhanced erodability. Removal of TA resulted in increased water uptake capacity and drug release, where 8% (w/w) TA was determined as the critical concentration threshold for divergence of release profiles. In conclusion, characterization of the resultant HII mesophase region provided information of the impact the individual components have on the physicochemical properties and potential drug release mechanisms. This high mitigating impact of TA on drug release indicates the use of TA as a tailoring agent, broadening the therapeutic applications of this LC system. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Formation of the twin galactic starburst regions NGC6334 and NGC6357

    NASA Astrophysics Data System (ADS)

    Torii, Kazufumi; Hasegawa, Keisuke; Ohama, Akio; Yamamoto, Hiroaki; Tachihara, Kengo; Fukui, Yasuo

    2015-08-01

    Since 2009, several molecular line observations toward the galactic high-mass star forming regions have indicated that cloud-cloud collisions (CCC) play an important role in forming high-mass stars; for example, super star clusters Westerlund2, NGC3603, and RCW38 (Furukawa et al. 2009; Fukui et al. 2014, 2015) and small galactic HII regions M20 and RCW120 which are each excited by a single O star (Torii et al. 2011, 2015). Using the NANTEN2 4-m telescope situated at Atacama, Chile, we have completed a large-scale molecular line mapping toward young galactic starburst regions NGC6334 and NGC6357. The two regions have several clusetrs which are rich in O stars having 30-100 MSun and are suggested to be physically connected with each other, although they are separated by 100 pc. Our new CO observations show that two molecular cloud complexes are distributed toward NGC6334 and NGC6357 at two different velocities, -3 km/s and -18 km/s. They have filamentary distributions elongated for over 100 pc nearly parallel to the galactic plane. The -3km/s complex apparently shows morphological agreements with the nebulosity in NGC6334 and NGC6357, and the -18km/s complex shows complementary distributions with the -3 km/s complex especially toward the O stars. Furthermore, intermediate velocity features which connect the two complexes are seen toward the same direction. These observational signatures indicate the physical association of the two cloud complexes with NGC6334 and NGC6357. We postulate a scenario that a collision between the two filamentary cloud complexes with a colliding velocity ~15 km/s triggered high-mass star formation in NGC6334 and NGC6357. The timescale of the collision, thus the high-mass star formation, is estimated to be less than 0.5 Myrs, which corresponds to a mass accretion rate up to 2×10-4 MSun/yr. Previous known CCC origin objects are the ones in which high-mass star were formed at a very limited volume less than 1pc3. In contrast, the CCC in NGC

  17. Regional Smart Growth Alliances

    EPA Pesticide Factsheets

    This page describes the Urban Land Institute regional smart growth alliances that received funding from EPA to help support economic development, accommodate growth, enhance quality of, and protect the environment in regions across the country.

  18. Region 9 Tribal Program

    EPA Pesticide Factsheets

    EPA Region 9 helps tribes strengthen management of environmental programs in Indian country, and ensure that tribes have a voice in decisions. The region serves 148 federally recognized tribes with the states of Arizona, California, and Nevada.

  19. ERLN Regional Support

    EPA Pesticide Factsheets

    Regional labs play important roles in the Environmental Response Laboratory Network. They can serve as point of contact; coordinate sample flow, special analytical service requests, or training exercises; and partner with regional emergency/disaster staff.

  20. Region 9 RTOC Charter

    EPA Pesticide Factsheets

    U.S. EPA Pacific Southwest (Region 9) Regional Tribal Operations Committee (RTOC) Charter as amended 11/13/2014: Mission, Goals, Scope, Structure & Membership, Meetings, Administration, Charter Amendment/Review, and Current Working Draft.

  1. [Regional aging in Germany].

    PubMed

    Bucher, H

    1996-01-01

    Elderly people in Germany have a specific regional distribution. Recent regional population projections show that these patterns will change. The most dynamic process of aging will take place in the suburban parts of the large western Germany agglomerations, whereas in eastern Germany aging concentrates in regions with a lower density. There will be a regional deconcentration of elderly people with consequences for the planning of infrastructure.

  2. Learning Regions in Germany

    ERIC Educational Resources Information Center

    Thinesse-Demel, Jutta

    2010-01-01

    In 2000, the German Federal Ministry of Education and Research (BMBF) launched the programme "Learning Regions--Providing Support for Networks'" in cooperation with the Lander. It was co-financed by the European Social Fund (ESF). Some 90 regions were selected and financially supported. After one year, 71 regions continued to build-up…

  3. Learning Regions in Germany

    ERIC Educational Resources Information Center

    Thinesse-Demel, Jutta

    2010-01-01

    In 2000, the German Federal Ministry of Education and Research (BMBF) launched the programme "Learning Regions--Providing Support for Networks'" in cooperation with the Lander. It was co-financed by the European Social Fund (ESF). Some 90 regions were selected and financially supported. After one year, 71 regions continued to build-up…

  4. The zitterbewegung region

    NASA Astrophysics Data System (ADS)

    Sidharth, B. G.; Das, Abhishek

    2017-07-01

    This paper deals with a precise description of the region of zitterbewegung below the Compton scale and the stochastic nature associated with it. We endeavor to delineate this particular region by means of Ito’s calculus and instigate certain features that are in sharp contrast with conventional physics. Interestingly, our work substantiates that the zitterbewegung region represents a pre-space-time region and from therein emerges the notion of our conventional space-time. Interestingly, this unique region engenders the relativistic and quantum mechanical aspects of space-time.

  5. Young open clusters in the Galactic star forming region NGC 6357

    NASA Astrophysics Data System (ADS)

    Massi, F.; Giannetti, A.; Di Carlo, E.; Brand, J.; Beltrán, M. T.; Marconi, G.

    2015-01-01

    Context. NGC 6357 is an active star forming region with very young massive open clusters. These clusters contain some of the most massive stars in the Galaxy and strongly interact with nearby giant molecular clouds. Aims: We study the young stellar populations of the region and of the open cluster Pismis 24, focusing on their relationship with the nearby giant molecular clouds. We seek evidence of triggered star formation "propagating" from the clusters. Methods: We used new deep JHKs photometry, along with unpublished deep Spitzer/IRAC mid-infrared photometry, complemented with optical HST/WFPC2 high spatial resolution photometry and X-ray Chandra observations, to constrain age, initial mass function, and star formation modes in progress. We carefully examine and discuss all sources of bias (saturation, confusion, different sensitivities, extinction). Results: NGC 6357 hosts three large young stellar clusters, of which Pismis 24 is the most prominent. We found that Pismis 24 is a very young (~1-3 Myr) open cluster with a Salpeter-like initial mass function and a few thousand members. A comparison between optical and infrared photometry indicates that the fraction of members with a near-infrared excess (i.e., with a circumstellar disk) is in the range 0.3-0.6, consistent with its photometrically derived age. We also find that Pismis 24 is likely subdivided into a few different subclusters, one of which contains almost all the massive members. There are indications of current star formation triggered by these massive stars, but clear age trends could not be derived (although the fraction of stars with a near-infrared excess does increase towards the Hii region associated with the cluster). The gas out of which Pismis 24 formed must have been distributed in dense clumps within a cloud of less dense gas ~1 pc in radius. Conclusions: Our findings provide some new insight into how young stellar populations and massive stars emerge, and evolve in the first few Myr after

  6. Reversed-polarity regions

    NASA Technical Reports Server (NTRS)

    Tang, F.

    1982-01-01

    It is found by a statistical study of 58 reversed-polarity regions (RPRs) covering the 11-year period 1969-1979 that RPRs (1) have a lifespan comparable to normal active regions, (2) do not show a tendency to rotate toward a more normal alignment, and (3) have stable configurations that do not suggest stress due to their anomalous magnetic alignment. As in normal regions, RPR magnetic complexity is found to be the primary factor in flare productivity. Weak-field RPRs produce no flares, and regions with complex spots produce more flares than regions with non-complex spots by a factor of five. The main difference between RPRs and normal regions lies in complex spot frequency, with less that 17% of normal active regions having such spots and fewer than 1.8% having long-lived complex ones, while 41% of RPRs have complex spots and 24% have long-lived complex spots.

  7. Reversed-polarity regions

    NASA Technical Reports Server (NTRS)

    Tang, F.

    1982-01-01

    It is found by a statistical study of 58 reversed-polarity regions (RPRs) covering the 11-year period 1969-1979 that RPRs (1) have a lifespan comparable to normal active regions, (2) do not show a tendency to rotate toward a more normal alignment, and (3) have stable configurations that do not suggest stress due to their anomalous magnetic alignment. As in normal regions, RPR magnetic complexity is found to be the primary factor in flare productivity. Weak-field RPRs produce no flares, and regions with complex spots produce more flares than regions with non-complex spots by a factor of five. The main difference between RPRs and normal regions lies in complex spot frequency, with less that 17% of normal active regions having such spots and fewer than 1.8% having long-lived complex ones, while 41% of RPRs have complex spots and 24% have long-lived complex spots.

  8. Spiral arms and massive star formation: Analysis of the CO face-on pictures of the galaxy

    NASA Technical Reports Server (NTRS)

    Clemens, D. P.; Sanders, D. B.; Scoville, N. Z.

    1986-01-01

    The face-on distribution of molecular gas in the first Galactic quadrant, derived from the Massachusetts-Stony Brook Galactic Plane CO Survey, was compared to the Galactic distribution of giant radio HII regions. The HII regions were found to preferentially select gas regions of higher than average density (more than twice the mean) and showed a strong correlation with the second power of the gas density. Systematic effects were tested with a Monte Carlo simulated HII region distribution and found to be negligible. The 135 HII regions were selected from the radio catalogs of Downes et at. (1980) and Wink et al. (1982). The HII regions were required to be within the CO survey 1 and b limits, within the solar circle, and not part of the 3 kpc expanding arm. The velocities of the HII regions were tabulated by the catalog authors and obvious associations with known objects and H2CO absorptions were used by them to assign distances. The distance assignments were here grouped into two categories; (1) those HII regions with definite distance assignments (85 objects); and (2) those HII regions with less secure distance assignments and those for which no near-far assignment was possible (50 objects).

  9. Robotics and regional anesthesia.

    PubMed

    Wehbe, Mohamad; Giacalone, Marilu; Hemmerling, Thomas M

    2014-10-01

    Robots in regional anesthesia are used as a tool to automate the performance of regional techniques reducing the anesthesiologist's workload and improving patient care. The purpose of this review is to show the latest findings in robotic regional anesthesia. The literature separates robots in anesthesia into two groups: pharmacological robots and manual robots. Pharmacological robots are mainly closed-loop systems that help in the titration of anesthetic drugs to patients undergoing surgery. Manual robots are mechanical robots that are used to support or replace the manual gestures performed by anesthesiologists. Although in the last decade researchers have focused on the development of decision support systems and closed-loop systems, more recent evidence supports the concept that robots can also be useful in performing regional anesthesia techniques. Robots can improve the performance and safety in regional anesthesia. In this review, we present the developments made in robotic and automated regional anesthesia, and discuss the current state of research in this field.

  10. Active Regions Blossoming

    NASA Image and Video Library

    2015-10-28

    As a pair of active regions began to rotate into view, their towering magnetic field lines above them bloomed into a dazzling display of twisting arches (Oct. 27-28, 2015). Some of the lines reached over and connected with the neighboring active region. Active regions are usually the source of solar storms. The images were taken in a wavelength of extreme ultraviolet light. http://photojournal.jpl.nasa.gov/catalog/PIA20048

  11. Transition Region Models

    NASA Astrophysics Data System (ADS)

    Hansteen, V.; Murdin, P.

    2000-11-01

    The SOLAR TRANSITION REGION comprises the PLASMA between the CHROMOSPHERE and the CORONA. In both of these regions the temperature is fairly uniform. The transition region, by contrast, is believed to be characterized by a very steep temperature rise from a chromospheric temperature of slightly less than 104 K to coronal temperatures on the order of 106 K. The goal of modeling the transition regi...

  12. Regions and Western Europe.

    ERIC Educational Resources Information Center

    Brunt, Barry M.

    1995-01-01

    Maintains that regional geography is undergoing important changes in its method of study to achieve a greater degree of relevancy in the context of a global system. Presents Western Europe as a case study to reflect this new approach. Includes 11 maps illustrating 6 generalizations applied to regional patterns. (CFR)

  13. MC-6 Casius Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-6 quadrangle, Casius region of Mars. Except for the highly dissected southwestern part, which contains faults, mesas, and buttes of Nilosyrtis Mensae, the Casius region is dominated by light-colored and dark, relatively smooth plains. Latitude range 30 to 65 degrees, longitude range -120 to -60 degrees.

  14. Ad Hoc Rural Regionalism

    ERIC Educational Resources Information Center

    Hamin, Elisabeth M.; Marcucci, Daniel J.

    2008-01-01

    A new regionalism has been much documented and researched for metropolitan areas; this article documents that there is a new rural regionalism as well. In the United States, these groups appear most likely to emerge in areas that are challenged by outcomes characterizing globalization's effects on the rural condition: namely, exurban or…

  15. The Regional Educational Laboratories.

    ERIC Educational Resources Information Center

    Office of Educational Research and Improvement (ED), Washington, DC. Office of Reform Assistance and Dissemination.

    The Regional Educational Laboratory Program is the U.S. Department of Education's largest research and development investment designed to help educators, policymakers, and communities improve schools and help all students attain their potential. The network of 10 regional laboratories works to ensure that those involved in education improvement at…

  16. Regionalism, Devolution and Education

    ERIC Educational Resources Information Center

    Bogdanor, Vernon

    1977-01-01

    Described are effects of political decentralization in the United Kingdom on political and social institutions, particularly education. The author concludes that regionalism could yield advantages of power decentralization, diversity of decision making, and educational systems which are more closely connected to regional and local traditions.…

  17. Forest regions of Montana

    Treesearch

    Stephen F. Arno

    1979-01-01

    In this paper, Montana is divided into eight geographic subdivisions called "forest regions," based on distributions of tree and undergrowth species and the relationship of these patterns to climate and topography. The regions serve as a geographic reference for describing patterns of forest vegetation across the State. Data on the distributions of plant...

  18. Politics, Planning and Regionalism.

    ERIC Educational Resources Information Center

    Zukosky, Jerome

    The concept of regionalism identifies the issues in public affairs pertaining to a region and develops structures through which citizens can participate in the decisionmaking process. This speech describes educational decisions in the State of New York as affected by local decentralization and by concentration of power at the State level. Relevant…

  19. Ad Hoc Rural Regionalism

    ERIC Educational Resources Information Center

    Hamin, Elisabeth M.; Marcucci, Daniel J.

    2008-01-01

    A new regionalism has been much documented and researched for metropolitan areas; this article documents that there is a new rural regionalism as well. In the United States, these groups appear most likely to emerge in areas that are challenged by outcomes characterizing globalization's effects on the rural condition: namely, exurban or…

  20. Introduction - regional monitoring programs

    Treesearch

    Richard L. Hutto; C. John Ralph

    2005-01-01

    There is increasing interest in the initiation of regional or statewide monitoring programs that are less extensive than national efforts such as the Breeding Bird Survey. A number of regional programs have been in existence for a decade or more, so the papers in this section represented an effort to bring together the collective experience of the people who had...

  1. REGIONAL EMAP PROPOSALS

    EPA Science Inventory

    The US EPA's Environmental Assessment and Monitoring Program (EMAP) annually funds regional EMAP (REMAP) projects through each of the regions to support the improvement of monitoring activities by the states. The last call for proposals emphasized the need to support biological m...

  2. REGIONAL EMAP PROPOSALS

    EPA Science Inventory

    The US EPA's Environmental Assessment and Monitoring Program (EMAP) annually funds regional EMAP (REMAP) projects through each of the regions to support the improvement of monitoring activities by the states. The last call for proposals emphasized the need to support biological m...

  3. Reversed-polarity regions

    NASA Technical Reports Server (NTRS)

    Tang, F.

    1980-01-01

    The 58 RPRS studied have a lifespan comparable to normal active regions and have no tendency to rotate toward a more normal alignment. They seem to have stable configurations with no apparent evidence suggesting stress due to their anomalous magnetic alignment. Magnetic complexity in RPRs is the key to flare productivity just as it is in normal regions - weak field RPRs produced no flares and regions with complex spots produced more flares than regions with noncomplex spots by a factor of 5. The RPRs however, differ from normal regions in the frequency of having complex spots, particularly the long lived complex spots, in them. Less than 17 percent of normal ARs have complex spots; less than 1.8 percent have long lived complex spots. In contrast, 41 percent of RPRs have complex spots and 24 percent have long lived complex spots.

  4. Metallicity Structure in the Milky Way Disk

    NASA Astrophysics Data System (ADS)

    Wenger, Trey; Balser, Dana S.; Anderson, Loren D.; Bania, Thomas M.

    2017-01-01

    Elemental abundances are an important constraint on theories of the formation and evolution of the Milky Way. We use HII regions as a probe of the Milky Way's metallicity structure. HII regions are the brightest objects in the Galaxy at radio wavelengths and are detected across the entire Galactic disk. In thermal equilibrium, metal abundances are expected to set the nebular electron temperature with high abundances producing low temperatures. We derive the metallicity of HII regions using an empirical relation between an HII region's radio recombination line-to-continuum ratio and nebular metallicity. Our previous studies have revealed azimuthal metallicity structure in the Galactic disk, indicating that the disk may not be as well mixed as expected. To extend this work, we obtained high quality radio recombination line and radio continuum measurements of 120 HII regions across the Galactic disk using the Jansky Very Large Array. Here we describe the observations, data reduction pipeline, and preliminary results from this study.

  5. Regional inequalities in mortality.

    PubMed Central

    Illsley, R; Le Grand, J

    1993-01-01

    STUDY OBJECTIVE--To examine the hypothesis of sustained and persistent inequalities in health between British regions and to ask how far they are a consequence of using standardised mortality ratios as the tool of measurement. DESIGN, SETTING AND PARTICIPANTS--Data are regional, age specific death rates at seven points in time from 1931 to 1987-89 for the British regions, reconstructed to make them comparable with the 1981 regional definitions. Log variance is used to measure inequality; regional rankings are also used. MEASUREMENTS AND MAIN RESULTS--There has been a substantial convergence in age specific death rates between regions in younger but not in older age groups. In younger age groups the historic north/south gradient has disappeared; it persists in older groups. CONCLUSIONS--Use of standardised mortality ratios obscures differences in the convergence rates of age specific death rates between regions. Simple conclusions about the persistence of a north/south divide are not justified. Different processes of change seem to be at work in different age groups. PMID:8120497

  6. Upper Extremity Regional Anesthesia

    PubMed Central

    Neal, Joseph M.; Gerancher, J.C.; Hebl, James R.; Ilfeld, Brian M.; McCartney, Colin J.L.; Franco, Carlo D.; Hogan, Quinn H.

    2009-01-01

    Brachial plexus blockade is the cornerstone of the peripheral nerve regional anesthesia practice of most anesthesiologists. As part of the American Society of Regional Anesthesia and Pain Medicine’s commitment to providing intensive evidence-based education related to regional anesthesia and analgesia, this article is a complete update of our 2002 comprehensive review of upper extremity anesthesia. The text of the review focuses on (1) pertinent anatomy, (2) approaches to the brachial plexus and techniques that optimize block quality, (4) local anesthetic and adjuvant pharmacology, (5) complications, (6) perioperative issues, and (6) challenges for future research. PMID:19282714

  7. Drycleaner Database - Region 7

    EPA Pesticide Factsheets

    THIS DATA ASSET NO LONGER ACTIVE: This is metadata documentation for the Region 7 Drycleaner Database (R7DryClnDB) which tracks all Region7 drycleaners who notify Region 7 subject to Maximum Achievable Control Technologiy (MACT) standards. The Air and Waste Management Division is the primary managing entity for this database. This work falls under objectives for EPA's 2003-2008 Strategic Plan (Goal 4) for Healthy Communities & Ecosystems, which are to reduce chemical and/or pesticide risks at facilities.

  8. Drycleaner Database - Region 7

    EPA Pesticide Factsheets

    THIS DATA ASSET NO LONGER ACTIVE: This is metadata documentation for the Region 7 Drycleaner Database (R7DryClnDB) which tracks all Region7 drycleaners who notify Region 7 subject to Maximum Achievable Control Technologiy (MACT) standards. The Air and Waste Management Division is the primary managing entity for this database. This work falls under objectives for EPA's 2003-2008 Strategic Plan (Goal 4) for Healthy Communities & Ecosystems, which are to reduce chemical and/or pesticide risks at facilities.

  9. Regional ocean data assimilation.

    PubMed

    Edwards, Christopher A; Moore, Andrew M; Hoteit, Ibrahim; Cornuelle, Bruce D

    2015-01-01

    This article reviews the past 15 years of developments in regional ocean data assimilation. A variety of scientific, management, and safety-related objectives motivate marine scientists to characterize many ocean environments, including coastal regions. As in weather prediction, the accurate representation of physical, chemical, and/or biological properties in the ocean is challenging. Models and observations alone provide imperfect representations of the ocean state, but together they can offer improved estimates. Variational and sequential methods are among the most widely used in regional ocean systems, and there have been exciting recent advances in ensemble and four-dimensional variational approaches. These techniques are increasingly being tested and adapted for biogeochemical applications.

  10. Energized Active Regions

    NASA Image and Video Library

    2017-06-02

    A pair of relatively small (but frenetic) active regions rotated into view, spouting off numerous small flares and sweeping loops of plasma (May 31-June 2, 2017). At first, only the one active region was observed, but mid-way though the video clip a second one behind the first can be picked out. The dynamic regions were easily the most remarkable areas on the sun during this 42-hour period. The images were taken in a wavelength of extreme ultraviolet light. Movies are available at https://photojournal.jpl.nasa.gov/catalog/PIA21756

  11. Regional Instrumentation Centers.

    ERIC Educational Resources Information Center

    Cromie, William J.

    1980-01-01

    Focuses on the activities of regional instrumentation centers that utilize the state-of-the-art instruments and methodology in basic scientific research. The emphasis is on the centers involved in mass spectroscopy, magnetic resonance spectroscopy, lasers, and accelerators. (SA)

  12. Complex Regional Pain Syndrome

    MedlinePlus

    ... regional pain syndrome is an uncommon form of chronic pain that usually affects an arm or a ... I need? Is my condition likely temporary or chronic? What types of treatments are available? Which do ...

  13. Complex Regional Pain Syndrome

    MedlinePlus

    Complex regional pain syndrome (CRPS) is a chronic pain condition. It causes intense pain, usually in the arms, hands, legs, or feet. ... in skin temperature, color, or texture Intense burning pain Extreme skin sensitivity Swelling and stiffness in affected ...

  14. Active Regions' Magnetic Connection

    NASA Image and Video Library

    2017-05-22

    Several bright bands of plasma connect from one active region to another, even though they are tens of thousands of miles away from each other (May 17-18, 2017). Active regions are, by their nature, strong magnetic areas with north and south poles. The plasma consists of charged particles that stream along the magnetic field lines between these two regions. These connecting lines are clearly visible in this wavelength of extreme ultraviolet light. Other loops and strands of bright plasma can be seen rising up and out of smaller active regions as well. The video covers about one day's worth of activity. Movies are available at https://photojournal.jpl.nasa.gov/catalog/PIA21638

  15. Regional Health Information Systems

    PubMed Central

    Fuller, Sherrilynne

    1997-01-01

    Abstract In general, there is agreement that robust integrated information systems are the foundation for building successful regional health care delivery systems. Integrated Advanced Information Management System (IAIMS) institutions that, over the years, have developed strategies for creating cohesive institutional information systems and services are finding that IAIMS strategies work well in the even more complex regional environment. The key elements of IAIMS planning are described and lessons learned are discussed in the context of regional health information systems developed. The challenges of aligning the various information agencies and agendas in support of a regional health information system are complex ; however, the potential rewards for health care in quality, efficacy, and cost savings are enormous. PMID:9067887

  16. Regional Screening Levels (RSLs)

    EPA Pesticide Factsheets

    Regional Screening Level RSL Home Page introduces risk assessors to Chemical Risk Assessment preliminary remediation goals PRG risk based concentration RBC and risk calculations for the assessment of human Health.

  17. Regional Response Teams

    EPA Pesticide Factsheets

    There are thirteen in the U.S., each representing a geographic region (including the Caribbean and the Pacific Basin). Composed of representatives from field offices of the agencies that make up the National Response Team, and state representatives.

  18. Regional Hearing Clerk

    EPA Pesticide Factsheets

    The Regional Hearing Clerk receives filings for proceedings under the Consolidated Rules of Practice Governing the Administrative Assessment of Civil Penalties and the Revocation/Termination or Suspension of Permits, 40 Code of Federal Regulations Part 22

  19. Regional Instrumentation Centers.

    ERIC Educational Resources Information Center

    Cromie, William J.

    1980-01-01

    Focuses on the activities of regional instrumentation centers that utilize the state-of-the-art instruments and methodology in basic scientific research. The emphasis is on the centers involved in mass spectroscopy, magnetic resonance spectroscopy, lasers, and accelerators. (SA)

  20. Mercury's South Polar Region

    NASA Image and Video Library

    This animation shows 89 wide-angle camera (WAC) images of Mercury’s south polar region acquired by the Mercury Dual Imaging System (MDIS) over one complete Mercury solar day (176 Earth days). Thi...

  1. First Detection of the [O(sub III)] 88 Micrometers Line at High Redshifts: Characterizing the Starburst and Narrow-Line Regions in Extreme Luminosity Systems

    NASA Technical Reports Server (NTRS)

    Ferkinhoff, C.; Hailey-Dunsheath, S.; Nikola, T.; Parshley, S. C.; Stacey, G. J.; Benford, D. J.; Staguhn, J. G.

    2010-01-01

    We have made the first detections of the 88 micrometers [O(sub III)] line from galaxies in the early universe, detecting the line from the lensed active galactic nucleus (AGN)/starburst composite systems APM 08279+5255 at z 3.911 and SMM J02399-0136 at z = 2.8076. The line is exceptionally bright from both systems, with apparent (lensed) luminosities approx.10(exp 11) Solar Luminosity, For APM 08279, the [O(sub III)] line flux can be modeled in a star formation paradigm, with the stellar radiation field dominated by stars with effective temperatures, T(sub eff) > 36,000 K, similar to the starburst found in M82. The model implies approx.35% of the total far-IR luminosity of the system is generated by the starburst, with the remainder arising from dust heated by the AGN. The 881,tm line can also be generated in the narrow-line region of the AGN if gas densities are around a few 1000 cu cm. For SMM J02399, the [O(sub III)] line likely arises from HII regions formed by hot (T(sub eff) > 40,000 K) young stars in a massive starburst that dominates the far-IR luminosity of the system. The present work demonstrates the utility of the [O(sub III)] line for characterizing starbursts and AGN within galaxies in the early universe. These are the first detections of this astrophysically important line from galaxies beyond a redshift of 0.05.s

  2. First Detection of the [O(sub III)] 88 Micrometers Line at High Redshifts: Characterizing the Starburst and Narrow-Line Regions in Extreme Luminosity Systems

    NASA Technical Reports Server (NTRS)

    Ferkinhoff, C.; Hailey-Dunsheath, S.; Nikola, T.; Parshley, S. C.; Stacey, G. J.; Benford, D. J.; Staguhn, J. G.

    2010-01-01

    We have made the first detections of the 88 micrometers [O(sub III)] line from galaxies in the early universe, detecting the line from the lensed active galactic nucleus (AGN)/starburst composite systems APM 08279+5255 at z 3.911 and SMM J02399-0136 at z = 2.8076. The line is exceptionally bright from both systems, with apparent (lensed) luminosities approx.10(exp 11) Solar Luminosity, For APM 08279, the [O(sub III)] line flux can be modeled in a star formation paradigm, with the stellar radiation field dominated by stars with effective temperatures, T(sub eff) > 36,000 K, similar to the starburst found in M82. The model implies approx.35% of the total far-IR luminosity of the system is generated by the starburst, with the remainder arising from dust heated by the AGN. The 881,tm line can also be generated in the narrow-line region of the AGN if gas densities are around a few 1000 cu cm. For SMM J02399, the [O(sub III)] line likely arises from HII regions formed by hot (T(sub eff) > 40,000 K) young stars in a massive starburst that dominates the far-IR luminosity of the system. The present work demonstrates the utility of the [O(sub III)] line for characterizing starbursts and AGN within galaxies in the early universe. These are the first detections of this astrophysically important line from galaxies beyond a redshift of 0.05.s

  3. Regional Discrimination Research

    DTIC Science & Technology

    1981-06-01

    regional phase amplitudes across southern Russia from earthquake sources in the Pamir Mountain region and Baikal area ....... .................. ... 11 7...and Southern Asia from explosions in east Kazakh .......... . 11. Comparison of peak L and maximum P amplitude measuremenZs for events in I. the...U.S.S.R. recorded outside the country ....... ................... ... 18 12. Comparison of peak amplitudes before and after Sn and in the Pn and Lg windows

  4. MC-16 Memnonia Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-16 quadrangle, Memnonia region of Mars. Heavily cratered highlands in the southern two-thirds are cut in the northeastern part by a large outflow channel, Mangala Vallis. The highlands are bounded to the north by undulating wind-eroded deposits and to the east by lava flows of the Tharsis region. Latitude range -30 to 0 degrees, longitude range 135 to 180 degrees.

  5. Gyrating Active Region

    NASA Image and Video Library

    2017-01-26

    On Jan. 20, 2017, NASA Solar Dynamics Observatory captured a small area of the sun highlighted three active region. Over half a day this active region sent dark swirls of plasma and bright magnetic arches twisting and turning above it. All the activity in the three areas was driven by competing magnetic forces. The dynamic action was observed in a wavelength of extreme ultraviolet light. Movies are available at http://photojournal.jpl.nasa.gov/catalog/PIA11703

  6. On regional geomagnetic charts

    USGS Publications Warehouse

    Alldredge, L.R.

    1987-01-01

    When regional geomagnetic charts for areas roughly the size of the US were compiled by hand, some large local anomalies were displayed in the isomagnetic lines. Since the late 1960s, when the compilation of charts using computers and mathematical models was started, most of the details available in the hand drawn regional charts have been lost. One exception to this is the Canadian magnetic declination chart for 1980. This chart was constructed using a 180 degrees spherical harmonic model. -from Author

  7. On the Measurement of Elemental Abundance Ratios in Inner Galaxy H II Regions

    NASA Technical Reports Server (NTRS)

    Simpson, Janet P.; Rubin, Robert H.; Colgan, Sean W. J.; Erickson, Edwin F.; Haas, Michael R.

    2004-01-01

    Although abundance gradients in the Milky Way Galaxy certainly exist, details remain uncertain, particularly in the inner Galaxy, where stars and H II regions in the Galactic plane are obscured optically. In this paper we revisit two previously studied, inner Galaxy H II regions: G333.6-0.2 and W43. We observed three new positions in G333.6-0.2 with the Kuiper Airborne Observatory and reobserved the central position with the Infrared Space Observatory's Long Wavelength Spectrometer in far-infrared lines of S++, N++, N+, and O++. We also added the N+ lines at 122 and 205 microns to the suite of lines measured in W43 by Simpson et al.. The measured electron densities range from approx. 40 to over 4000 per cu cm in a single HII region, indicating that abundance analyses must consider density variations, since the critical densities of the observed lines range from 40 to 9000 per cu cm. We propose a method to handle density variations and make new estimates of the S/H and N/H abundance ratios. We find that our sulfur abundance estimates for G333.6-0.2 and W43 agree with the S/H abundance ratios expected for the gradient previously reported by Simpson et al., with the S/H values revised to be smaller owing to changes in collisional excitation cross sections. The estimated N/H, S/H, and N/S ratios are the most reliable because of their small corrections for unseen ionization states (< or approx. 10%). The estimated N/S ratios for the two sources are smaller than what would be calculated from the N/H and S/H ratios in our previous paper. If all low excitation H II regions had similar changes to their N/S ratios as a result of adding measurements of N+ to previous measurements of N++, there would be no or only a very small gradient in N/S. This is interesting because nitrogen is considered to be a secondary element and sulfur is a primary element in galactic chemical evolution calculations. We compute models of the two H II regions to estimate corrections for the other

  8. Modeling the transition region

    NASA Astrophysics Data System (ADS)

    Singer, Bart A.

    1994-04-01

    The calculation of engineering flows undergoing laminar-turbulent transition presents special problems. Mean-flow quantities obey neither the fully laminar nor the fully turbulent correlations. In addition, local maxima in skin friction, wall temperature, and heat transfer often occur near the end of the transition region. Traditionally, modeling this region has been important for the design of turbine blades, where the transition region is long in relation to the chord length of the blade. More recently, the need for better transition-region models has been recognized by designers of hypersonic vehicles where the high Mach number, the low Reynolds number, and the low-disturbance flight environment emphasize the importance of the transition region. Needless to say, a model that might work well for the transitional flows typically found in gas turbines will not necessarily work well for the external surface of a hypersonic vehicle. In Section 2 of this report, some of the important flow features that control the transition region will be discussed. In Section 3, different approaches to the modeling problem will be summarized and cataloged. Fully turbulent flow models will be discussed in detail in Section 4; models specifically designed for transitional flow, in Section 5; and the evaluation of models, in Section 6.

  9. Northeast Regional Biomass Program

    SciTech Connect

    Lusk, P.D.

    1992-12-01

    The Northeast Regional Biomass Program has been in operation for a period of nine years. During this time, state managed programs and technical programs have been conducted covering a wide range of activities primarily aim at the use and applications of wood as a fuel. These activities include: assessments of available biomass resources; surveys to determine what industries, businesses, institutions, and utility companies use wood and wood waste for fuel; and workshops, seminars, and demonstrations to provide technical assistance. In the Northeast, an estimated 6.2 million tons of wood are used in the commercial and industrial sector, where 12.5 million cords are used for residential heating annually. Of this useage, 1504.7 mw of power has been generated from biomass. The use of wood energy products has had substantial employment and income benefits in the region. Although wood and woodwaste have received primary emphasis in the regional program, the use of municipal solid waste has received increased emphasis as an energy source. The energy contribution of biomass will increase as potentia users become more familiar with existing feedstocks, technologies, and applications. The Northeast Regional Biomass Program is designed to support region-specific to overcome near-term barriers to biomass energy use.

  10. Ultrasound in regional anaesthesia.

    PubMed

    Griffin, J; Nicholls, B

    2010-04-01

    Ultrasound guidance is rapidly becoming the gold standard for regional anaesthesia. There is an ever growing weight of evidence, matched with improving technology, to show that the use of ultrasound has significant benefits over conventional techniques, such as nerve stimulation and loss of resistance. The improved safety and efficacy that ultrasound brings to regional anaesthesia will help promote its use and realise the benefits that regional anaesthesia has over general anaesthesia, such as decreased morbidity and mortality, superior postoperative analgesia, cost-effectiveness, decreased postoperative complications and an improved postoperative course. In this review we consider the evidence behind the improved safety and efficacy of ultrasound-guided regional anaesthesia, before discussing its use in pain medicine, paediatrics and in the facilitation of neuraxial blockade. The Achilles' heel of ultrasound-guided regional anaesthesia is that anaesthetists are far more familiar with providing general anaesthesia, which in most cases requires skills that are achieved faster and more reliably. To this ends we go on to provide practical advice on ultrasound-guided techniques and the introduction of ultrasound into a department.

  11. NV PFA Regional Data

    SciTech Connect

    James Faulds

    2015-10-28

    This project focused on defining geothermal play fairways and development of a detailed geothermal potential map of a large transect across the Great Basin region (96,000 km2), with the primary objective of facilitating discovery of commercial-grade, blind geothermal fields (i.e. systems with no surface hot springs or fumaroles) and thereby accelerating geothermal development in this promising region. Data included in this submission consists of: structural settings (target areas, recency of faulting, slip and dilation potential, slip rates, quality), regional-scale strain rates, earthquake density and magnitude, gravity data, temperature at 3 km depth, permeability models, favorability models, degree of exploration and exploration opportunities, data from springs and wells, transmission lines and wilderness areas, and published maps and theses for the Nevada Play Fairway area.

  12. Regional anesthesia at home

    PubMed Central

    Cheng, Gloria S.; Choy, Lynna P.; Ilfeld, Brian M.

    2009-01-01

    Purpose of review To review the recently published peer-reviewed literature involving regional anesthesia and analgesia in patients at home. Recent findings The potential benefits and risks of regional anesthesia and analgesia at home are pertinent queries, and increased data regarding these topics are rapidly becoming available. Of particular interest is the use of continuous peripheral nerve blocks at home and their potential effect upon hospitalization duration and recovery profile. Summary Advantages of regional techniques include site-specific anesthesia and decreased postoperative opioid use. For shoulder surgeries, the interscalene block provides effective analgesia with minimal complications, whereas the impact and risks of intraarticular injections remain unclear. Perineural catheters are an analgesic option that offer improved pain relief among other benefits. They are now being used at home in both adult and pediatric populations. PMID:18660659

  13. Stability of regional configurations

    SciTech Connect

    Canavan, G.H.

    1998-08-13

    At moderate force levels the first strike stability index is proportional to the first strike cost, so as the attacker minimizes attack costs, he automatically minimizes stability. Weapons grow rapidly and saturate to levels comparable to the number of value targets held at risk. This growth could appear destabilizing to dominant regional powers, whose response could in turn appear threatening to the major nuclear powers, which could slow or halt efforts towards deep reductions. The fundamental way to alter these pressures appears to be through reducing the likelihood of regional crises by removing these fundamental antagonisms.

  14. Agitated Active Region

    NASA Image and Video Library

    2016-10-11

    An active region just rotating into view gave us a perfect view of the tussle of magnetic field lines above it (Oct. 10-11, 2016). The particles spiraling along the magnetic field lines become visible in extreme ultraviolet light, helping us to see the struggle going on. There were no eruptions during this period, although active regions are usually the source for solar storms. The video clip covers just one day's worth of activity. Movies are available at http://photojournal.jpl.nasa.gov/catalog/PIA21109

  15. 2011 Bayou Regional

    NASA Image and Video Library

    2011-03-19

    Students from 38 high school teams in seven states competed for top honors during the 2011 FIRST (For Inspiration and Recognition of Science and Technology) Robotics Bayou Regional competition held March 17-19 in the New Orleans area. In this photo, members of the robotics team from Gulfport High School guide their robot during the annual tournament. The robotics competition is designed to help encourage students to pursue studies and careers in the areas of science, technology, engineering and mathematics. John C. Stennis Space Center is a supporter of FIRST activities and the Bayou Regional tournament.

  16. Jumpy Active Region

    NASA Image and Video Library

    2017-01-03

    A close-up view of one day in the life of a rather small active region shows the agitation and dynamism of its magnetic field (Dec. 21, 2016). This wavelength of extreme ultraviolet light reveals particles as they spin along the cascading arches of magnetic field lines above the active region. Some darker plasma rises up and spins around at the edge of the sun near the end of the video clip also being pulled by unseen magnetic forces. Movies are available at http://photojournal.jpl.nasa.gov/catalog/PIA15032

  17. REGIONAL CONFERENCE SUMMARIES, 1966.

    ERIC Educational Resources Information Center

    Bureau of Adult, Vocational, and Technical Education (DHEW/OE), Washington, DC. Div. of Vocational and Technical Education.

    AN AVERAGE OF 200 TEACHER EDUCATORS, STATE DIRECTORS, LAYMEN, AND REPRESENTATIVES OF VARIOUS AGENCIES ATTENDED EACH OF NINE REGIONAL CONFERENCES CONDUCTED THROUGHOUT THE UNITED STATES TO DISCUSS THE INFLUENCE OF SOCIAL AND ECONOMIC CHANGES AND PROBLEMS IN PLANNING AND CONDUCTING VOCATIONAL AND TECHNICAL EDUCATION PROGRAMS. MAJOR SPEECHES PRESENTED…

  18. Regional Population Dynamics

    Treesearch

    Andrew Birt

    2011-01-01

    The population dynamics of the southern pine beetle (SPB) exhibit characteristic fluctuations between relatively long endemic and shorter outbreak periods. Populations exhibit complex and hierarchical spatial structure with beetles and larvae aggregating within individual trees, infestations with multiple infested trees, and regional outbreaks that comprise a large...

  19. Norway's Regional Colleges

    ERIC Educational Resources Information Center

    Kintzer, Frederick C.

    1974-01-01

    Created in 1969 as a 3-college system coordinated by the Regional College section of the Ministry of Education, the current 6 institutions represent Norway's attempt to extend equal opportunity and employment-oriented education to rural and remote areas. (Editor)

  20. TVA and regional development

    SciTech Connect

    Not Available

    1983-01-01

    Although TVA is best known as a producer of electric power, its mission, in the words of Franklin D. Roosevelt, called for a program that touches and gives life to all forms of human concerns. This booklet provides general information about the scores of ways - beyond the electric power generation - in which the agency serves the region and nation.

  1. Australia's Regional Youth Exodus.

    ERIC Educational Resources Information Center

    Gabriel, M.

    2002-01-01

    Examines media coverage of youth outmigration from Tasmania in the context of Australia's regional crisis. Focuses on how young people are constructed by others and positioned in others' visions of their rural home towns. Discusses two recurring narratives: strategies to keep youth at home, and preoccupation with the "best and brightest"…

  2. MC-24 Phaethontis Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-24 quadrangle, Phaethontis region of Mars. The Phaethontis quadrangle is dominated by heavily cratered highlands and low-lying areas forming relatively smooth plains. Latitude range -65 to -30 degrees, longitude range 120 to 180.

  3. MC-2 Diacria Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-2 quadrangle, Diacria region of Mars. The northern two-thirds is dominated by relatively smooth plains. The southeastern part is marked by aureole deposits of the largest known volcano in the solar system, Olympus Mons. Latitude range 30 to 65 degrees, longitude range 120 to 180.

  4. MC-14 Amenthes Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-14 quadrangle, Amenthes region of Mars. The southern part includes heavily cratered highlands. The northern part is dominated by relatively smooth plains of Elysium Planitia and the eastern half of the Isidis basin. Latitude range 0 to 30 degrees, longitude range -135 to -90 degrees.

  5. MC-3 Arcadia Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-3 quadrangle, Arcadia region of Mars. The southern part contains the large shield volcano, Alba Patera, and the highly faulted Tempe Terra province, which includes many small volcanoes. The northern part is dominated by relatively smooth plains. Latitude range 30 to 65 degrees, longitude range 60 to 120 degrees.

  6. Regional Norms for English.

    ERIC Educational Resources Information Center

    Kachru, Braj B.

    The debate continues about regional norms for English usage around the world, although the discussion has become more realistic and less didactic. Educated non-native varieties are increasingly accepted, distinctions are being made between national and international language uses, and localized varieties are no longer considered as necessarily…

  7. Australia's Regional Youth Exodus.

    ERIC Educational Resources Information Center

    Gabriel, M.

    2002-01-01

    Examines media coverage of youth outmigration from Tasmania in the context of Australia's regional crisis. Focuses on how young people are constructed by others and positioned in others' visions of their rural home towns. Discusses two recurring narratives: strategies to keep youth at home, and preoccupation with the "best and brightest"…

  8. Regionalism. Clip and Save.

    ERIC Educational Resources Information Center

    Hubbard, Guy

    2002-01-01

    Focuses on the art movement, called Regionalism, discussing the painters involved and describing the characteristics of the art movement. Provides a set of learning activities and background information on John Steuart Curry. Includes a discussion of Curry's painting, "Tornado Over Kansas," and a reproduction of the painting. (CMK)

  9. Regional cancer pain syndromes.

    PubMed

    Chang, Victor T; Janjan, Nora; Jain, Subash; Chau, Chi

    2006-12-01

    Cancer pain often presents in a body region. This review summarizes articles from 1999-2004 relevant to cancer pain syndromes in the head and neck, chest, back, abdomen, pelvis, and limbs. Although the evidence is limited, progress is being made in further development of the evidence base to support and guide current practice.

  10. Regional native plant strategies

    Treesearch

    Wendell G. Hassell

    1999-01-01

    Because of increasing public interest in native plants, regional groups have been cooperating to develop native species. The Federal Native Plants Initiative was formed in 1994 to coordinate and encourage the development and use of native plants. The program they developed includes public involvement, organizational structure, technical work groups, implementation...

  11. Climatic Concepts and Regions.

    ERIC Educational Resources Information Center

    Thomas, Paul F.

    Designed for students in grades 7 through 12, this teaching unit presents illustrative resource materials depicting concepts related to climate and geographic regions. Emphasis is on giving students an understanding of climatic elements and factors, not as isolated, disjointed entities, but as a dynamic interplay of forces having a very definite…

  12. Regionalism. Clip and Save.

    ERIC Educational Resources Information Center

    Hubbard, Guy

    2002-01-01

    Focuses on the art movement, called Regionalism, discussing the painters involved and describing the characteristics of the art movement. Provides a set of learning activities and background information on John Steuart Curry. Includes a discussion of Curry's painting, "Tornado Over Kansas," and a reproduction of the painting. (CMK)

  13. Regionalism in Scottish Universities

    ERIC Educational Resources Information Center

    Hutchison, Dougal

    1976-01-01

    It is well-known that Scottish universities are highly local institutions and that over two-fifth of Scottish university students live at home. Attempts to ascertain if this regionalism has relaxed over the past twenty years with student grant regulations, improvement in communications and the increasing affluence of today's society. (Author/RK)

  14. Neptune South Polar Region

    NASA Image and Video Library

    1999-07-25

    This image of Neptune south polar region was obtained by NASA Voyager on Aug. 23, 1989. The smallest cloud features are 45 kilometers 28 miles in diameter. The image shows the discovery of shadows in Neptune atmosphere, shadows cast onto a deep cl

  15. Recipe for Regional Development.

    ERIC Educational Resources Information Center

    Baldwin, Fred D.

    1994-01-01

    The Ceramics Corridor has created new jobs in New York's Appalachian region by fostering ceramics research and product development by small private companies. Corridor business incubators offer tenants low overhead costs, fiber-optic connections to Alfred University's mainframe computer, rental of lab space, and use of equipment small companies…

  16. Climatic Concepts and Regions.

    ERIC Educational Resources Information Center

    Thomas, Paul F.

    Designed for students in grades 7 through 12, this teaching unit presents illustrative resource materials depicting concepts related to climate and geographic regions. Emphasis is on giving students an understanding of climatic elements and factors, not as isolated, disjointed entities, but as a dynamic interplay of forces having a very definite…

  17. Venus - Lada Terra Region

    NASA Image and Video Library

    1996-02-01

    This NASA Magellan radar image mosaic is of part of Venus, centered at 51 degrees south latitude, 21 degrees east longitude. Running from west to east across the center of the image is part of a wide lava channel in the Lada Terra region of Venus. http://photojournal.jpl.nasa.gov/catalog/PIA00219

  18. Venus - Phoebe Region

    NASA Image and Video Library

    1996-02-05

    This radar image from NASA Magellan is of part of the Phoebe region of Venus. It is a mosaic of parts of revolutions 146 and 147 acquired in the first radar test on Aug. 16, 1990. http://photojournal.jpl.nasa.gov/catalog/PIA00211

  19. Benchmarks: WICHE Region 2012

    ERIC Educational Resources Information Center

    Western Interstate Commission for Higher Education, 2013

    2013-01-01

    Benchmarks: WICHE Region 2012 presents information on the West's progress in improving access to, success in, and financing of higher education. The information is updated annually to monitor change over time and encourage its use as a tool for informed discussion in policy and education communities. To establish a general context for the…

  20. Iapetus' Equatorial Region

    NASA Image and Video Library

    2007-10-09

    Cassini made a close flyby of Saturn's moon Iapetus on Sept. 10, 2007, and the visual and infrared mapping spectrometer obtained these images during that event. These two images show a higher resolution version of the equatorial region shown in PIA10010. The equatorial region includes the equatorial bulge which shows no differences in these compositions compared to surrounding regions. The color image on the right shows the results of mapping for three components of Iapetus' surface: carbon dioxide that is trapped or adsorbed in the surface (red), water in the form of ice (green), and a newly-discovered effect due to trace amount of dark particles in the ice creating what scientists call Rayleigh scattering (blue). The Rayleigh scattering effect is the main reason why the Earth's sky appears blue. There is a complex transition zone from the dark region, on the right, which is high in carbon dioxide, to the more ice-rich region on the left. Some crater floors are filled with carbon dioxide-rich dark material. As the ice becomes cleaner to the left, the small dark particles become more scattered and increase the Rayleigh scattering effect, again indicative of less than 2 percent dark sub-0.5-micron particles. The visual and infrared mapping spectrometer is like a digital camera, but instead of using three colors, it makes images in 352 colors, or wavelengths, from the ultraviolet to the near-infrared. The many wavelengths produce a continuous spectrum in each pixel, and these spectra measure how light is absorbed by different materials. By analyzing the absorptions expressed in each pixel, a map of the composition at each location on the moon can be constructed. http://photojournal.jpl.nasa.gov/catalog/PIA10011

  1. Hawaii Regional Sediment Management: Regional Sediment Budget for the Poipu Region of Kauai, HI

    DTIC Science & Technology

    2013-06-01

    originator. Hawaii Regional Sediment Management: Regional Sediment Budget for the Poipu Region of Kauai , HI Edited by Jessica H. Podoski PURPOSE...Island of Kauai , HI, as part of the Hawaii Regional Sediment Management (RSM) initiative funded by the US Army Corps of Engineers (USACE) RSM Program...POH), is to investigate RSM opportunities along all shoreline regions in Hawaii . Initial RSM regions on Kauai include the Kekaha Region and the

  2. Hawaii Regional Sediment Management: Regional Sediment Budget for the Kekaha Region of Kauai, HI

    DTIC Science & Technology

    2013-06-01

    originator. Hawaii Regional Sediment Management: Regional Sediment Budget for the Kekaha Region of Kauai , HI Edited by Jessica H. Podoski PURPOSE...Island of Kauai , HI, as part of the Hawaii Regional Sediment Management (RSM) initiative funded by the US Army Corps of Engineers (USACE) RSM Program...POH), is to investigate RSM opportunities along all shoreline regions in Hawaii . Initial RSM regions on Kauai include the Kekaha Region and the

  3. Active region seismology

    NASA Technical Reports Server (NTRS)

    Bogdan, Tom; Braun, D. C.

    1995-01-01

    Active region seismology is concerned with the determination and interpretation of the interaction of the solar acoustic oscillations with near-surface target structures, such as magnetic flux concentration, sunspots, and plage. Recent observations made with a high spatial resolution and a long temporal duration enabled measurements of the scattering matrix for sunspots and solar active regions to be carried out as a function of the mode properties. Based on this information, the amount of p-mode absorption, partial-wave phase shift, and mode mixing introduced by the sunspot, could be determined. In addition, the possibility of detecting the presence of completely submerged magnetic fields was raised, and new procedures for performing acoustic holography of the solar interior are being developed. The accumulating evidence points to the mode conversion of p-modes to various magneto-atmospheric waves within the magnetic flux concentration as being the unifying physical mechanism responsible for these diverse phenomena.

  4. Arctic region mapping tool

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2012-08-01

    An interactive online mapping tool is now available to assist with scientific, environmental, and emergency response needs in the Arctic region, the National Oceanic and Atmospheric Administration (NOAA) announced on 31 July. The Environmental Response Management Application (ERMA®) already has been used in other regions, including in the Gulf of Mexico, as part of the response to the Deepwater Horizon oil spill in 2010. The tool—which is a product of the combined work of NOAA, the U.S. Department of the Interior's Bureau of Safety and Environmental Enforcement (BSEE), the University of New Hampshire, and others—offers near-real time oceanographic observations, weather data, environmental and commercial information, and other data.

  5. Regional technology transfer program

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The continuing operation is reported of a jointly state- and NASA-sponsored Regional Dissemination Center serving the southeastern United States. The NC/STRC offers automated searching of large information collections, such as that assembled by NASA, with emphasis on textile-related files to serve regional industry. During this period, NC/STRC conducted an in-depth analysis of its marketing programs and prepared a series of brochures aimed at various segments of industry. Heavy emphasis was also placed on the Library Search Service inaugurated by NC/STRC, and a total of 32 universities now participate in this service. Smaller schools are served through the university network. Although the nationwide industrial recession caused a general drop in search requests, NC/STRC processed a total of 838 retrospective searches during this period: 39.97% for its industrial clients, 22.9% for university libraries, and 37.1% for other RDC's.

  6. MC-7 Cebrenia Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-7 quadrangle, Cebrenia region of Mars. The northwestern two-thirds is dominated by light-colored and dark, relatively smooth plains. The southeastern part is marked by one of three prominent Elysium shield volcanoes, Hecates Tholus, and the ridge system of Phlegra Montes. Latitude range 30 to 65 degrees, longitude range -180 to -120 degrees.

  7. MC-23 Aeolis Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-23 quadrangle, Aeolis region of Mars. The southern part is dominated by heavily cratered highlands that are cut by two large channels having features characteristic of terrestrial river beds. The highlands are separated from the northern plains of Elysium Planitia by a highly dissected, discontinuous northwest trending scarp. The northeastern part is marked by a large shield volcano, Apollinaris Patera. Latitude range - 30 to 0 degrees, longitude range -180 to -135 degrees.

  8. MC-12 Arabia Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-12 quadrangle, Arabia region of Mars. Heavily cratered highlands dominate the Arabia quadrangle. The northeastern part is marked by a large impact crater, Cassini. Cassini is an ancient remnant of the many large impact events that occurred during the period of heavy bombardment. Latitude range 0 to 30 degrees, longitude range -45 to 0 degrees.

  9. Mc-9 Tharsis Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-9 quadrangle, Tharsis region of Mars. Three of the four largest shield volcanoes on Mars--Olympus, Ascraeus, and Pavonis Montes--lie within the Tharsis quadrangle, together with several smaller shields. The north-central part is marked by highly faulted terrain of Ceraunius Fossae. Latitude range 0 to 30 degrees, longitude range 90 to 135 degrees.

  10. MC-26 Argyre Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-26 quadrangle, Argyre region of Mars. The west-central part is marked by the large Argyre impact basin, defined by a rim of rugged mountain blocks that surrounds a nearly circular expanse of light-colored plains 800 km across. The large basin is surrounded by heavily cratered highlands. Latitude range -65 to -30 degrees, longitude range 0 to 60 degrees.

  11. Regionalism and Secession

    DTIC Science & Technology

    2015-03-01

    integration. See Ramon Maiz , Francisco Caamaño, and Miguel Azpitarte, “The Hidden Counterpoint of Spanish Federalism: Recentralization and Resymmetrization...Sobre Cataluña (Madrid: Los Libros de la Catarata, 2014), 112. 269 Ibid. 60 autonomy and not independence.270 Catalan nationalists, aided by the media...de Escritos Sobre Cataluña. Madrid: Los Libros de la Catarata, 2014. Domorenok, Ekaterina,. “The Committee of the Regions: In Search of Identity

  12. Region 9 Tribal Lands

    EPA Pesticide Factsheets

    Dataset of all Indian Reservations in US EPA Region 9 (California, Arizona and Nevada) with some reservation border areas of adjacent states included (adjacent areas of Colorado, New Mexico and Utah). Reservation boundaries are compiled from multiple sources and are derived from several different source scales. Information such as reservation type, primary tribe name are included with the feature dataset. Public Domain Allotments are not included in this data set.

  13. Regional Seismic Wave Propagation

    DTIC Science & Technology

    1979-07-31

    Baikal to the Pamirs, earthquakes occuring in the Baikal region, Sinkiang , the Gobi desert, southwest China and the Himalayas generated Lg/P ratios...data were obtained from stations within the USSR from earthquake events occuring in Baikal, Sinkiang , the Gobi desert, Southwest China and the...earthquakes originating in the Sinkiang province and recorded by seismo- graphic stations along the Pamir-Lena River profile [25] 0 - recorded by short

  14. Transition Region Flows

    NASA Astrophysics Data System (ADS)

    Brekke, P.; Murdin, P.

    2000-11-01

    Ultraviolet emission lines emitted from the SOLAR TRANSITION REGION are often shifted from their expected rest wavelengths. Shifts of spectral lines are due to the so-called DOPPLER EFFECT, where the source of emission is moving either away from or towards the observer, causing a change in the apparent wavelength. The shifted emission lines are most often interpreted as a flow of plasma along ...

  15. Northwest Regional Climate Assessment

    NASA Technical Reports Server (NTRS)

    Lipschultz, Fred

    2011-01-01

    Objectives are to establish a continuing, inclusive National process that: 1) synthesizes relevant science and information 2) increases understanding of what is known & not known 3) identifies information needs related to preparing for climate variability and change, and reducing climate impacts and vulnerability 4) evaluates progress of adaptation & mitigation activities 5) informs science priorities 6) builds assessment capacity in regions and sectors 7) builds understanding & skilled use of findings

  16. Regional Renewable Energy Cooperatives

    NASA Astrophysics Data System (ADS)

    Hazendonk, P.; Brown, M. B.; Byrne, J. M.; Harrison, T.; Mueller, R.; Peacock, K.; Usher, J.; Yalamova, R.; Kroebel, R.; Larsen, J.; McNaughton, R.

    2014-12-01

    We are building a multidisciplinary research program linking researchers in agriculture, business, earth science, engineering, humanities and social science. Our goal is to match renewable energy supply and reformed energy demands. The program will be focused on (i) understanding and modifying energy demand, (ii) design and implementation of diverse renewable energy networks. Geomatics technology will be used to map existing energy and waste flows on a neighbourhood, municipal, and regional level. Optimal sites and combinations of sites for solar and wind electrical generation (ridges, rooftops, valley walls) will be identified. Geomatics based site and grid analyses will identify best locations for energy production based on efficient production and connectivity to regional grids and transportation. Design of networks for utilization of waste streams of heat, water, animal and human waste for energy production will be investigated. Agriculture, cities and industry produce many waste streams that are not well utilized. Therefore, establishing a renewable energy resource mapping and planning program for electrical generation, waste heat and energy recovery, biomass collection, and biochar, biodiesel and syngas production is critical to regional energy optimization. Electrical storage and demand management are two priorities that will be investigated. Regional scale cooperatives may use electric vehicle batteries and innovations such as pump storage and concentrated solar molten salt heat storage for steam turbine electrical generation. Energy demand management is poorly explored in Canada and elsewhere - our homes and businesses operate on an unrestricted demand. Simple monitoring and energy demand-ranking software can easily reduce peaks demands and move lower ranked uses to non-peak periods, thereby reducing the grid size needed to meet peak demands. Peak demand strains the current energy grid capacity and often requires demand balancing projects and

  17. Regional Shelter Analysis Methodology

    SciTech Connect

    Dillon, Michael B.; Dennison, Deborah; Kane, Jave; Walker, Hoyt; Miller, Paul

    2015-08-01

    The fallout from a nuclear explosion has the potential to injure or kill 100,000 or more people through exposure to external gamma (fallout) radiation. Existing buildings can reduce radiation exposure by placing material between fallout particles and exposed people. Lawrence Livermore National Laboratory was tasked with developing an operationally feasible methodology that could improve fallout casualty estimates. The methodology, called a Regional Shelter Analysis, combines the fallout protection that existing buildings provide civilian populations with the distribution of people in various locations. The Regional Shelter Analysis method allows the consideration of (a) multiple building types and locations within buildings, (b) country specific estimates, (c) population posture (e.g., unwarned vs. minimally warned), and (d) the time of day (e.g., night vs. day). The protection estimates can be combined with fallout predictions (or measurements) to (a) provide a more accurate assessment of exposure and injury and (b) evaluate the effectiveness of various casualty mitigation strategies. This report describes the Regional Shelter Analysis methodology, highlights key operational aspects (including demonstrating that the methodology is compatible with current tools), illustrates how to implement the methodology, and provides suggestions for future work.

  18. Tangled up Active Region

    NASA Image and Video Library

    2017-09-27

    This close-up image of the sun presents an active region in profile as it rotated out of view. We can observe both the bright arching field lines and smaller pieces of darker matter in their midst being pulled back and forth just above the Sun's surface over about 36 hours (July 20-22, 2011). Both of these physical responses were caused by strong, tangled magnetic forces that are constantly evolving and reorganizing within the active region. Other active regions can be seen in the foreground as well. The image and movie were taken in extreme ultraviolet light of ionized iron heated to one million degrees. To view a hd video of this event go here: www.flickr.com/photos/gsfc/6006013038 Credit: NASA/GSFC/SDO NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  19. Regional technical cooperation.

    PubMed

    Sullivan, P H

    1997-01-01

    The AIDS epidemic threatens economic development in Asia because Asia offers fertile conditions for unchecked transmission and because the epidemic has the most impact on young adults who make up a large sector of the work force. Prevention is still possible, however, and should be viewed as an investment in the future. Effective prevention strategies will have regional as well as domestic components and will recognize the hierarchy of interventions and spread the burden among the public sector, nongovernmental organizations (NGOs), and the private sector in each country. The public sector should 1) ensure that markets function well and do not discriminate against infected individuals; 2) provide a supportive macroeconomic framework of fiscal, trade, and credit policies; and 3) provide public and quasipublic goods, such as information and training. The contribution of NGOs should are vital for reducing the suffering involved with HIV/AIDS. Private sector contributions can include care facilities, research and development, and funding. The private sector must realize that the threat to the stock of human capital posed by HIV/AIDS will reduce profits. The regional dimensions of the HIV/AIDS epidemic relate 1) to factors that contribute to transmission and 2) to approaches that can be taken to prevent transmission and curb its impact. The Greater Mekong Subregion Work Program on HIV/AIDS is a good example of a cooperative regional effort to prevent and control HIV/AIDS. The epidemic requires cooperation among sectors and among countries.

  20. Jupiter Equatorial Region

    NASA Image and Video Library

    1998-03-06

    This photographic mosaic of images from NASA's Galileo spacecraft covers an area of 34,000 kilometers by 22,000 kilometers (about 21,100 by 13,600 miles) in Jupiter's equatorial region. The dark region near the center of the mosaic is an equatorial "hotspot" similar to the site where the Galileo Probe parachuted into Jupiter's atmosphere in December 1995. These features are holes in the bright, reflective, equatorial cloud layer where heat from Jupiter's deep atmosphere can pass through. The circulation patterns observed here along with the composition measurements from the Galileo Probe suggest that dry air may be converging and sinking over these regions, maintaining their cloud-free appearance. The bright oval in the upper right of the mosaic as well as the other smaller bright features are examples of upwelling of moist air and condensation. These images were taken on December 17, 1996, at a range of 1.5 million kilometers (about 930,000 miles) by the Solid State Imaging camera system aboard Galileo. North is at the top. The mosaic covers latitudes 1 to 19 degrees and is centered at longitude 336 degrees west. The smallest resolved features are tens of kilometers in size. http://photojournal.jpl.nasa.gov/catalog/PIA00604

  1. Regionalization Lessons from Denmark.

    PubMed

    Vrangbaek, Karsten

    2016-01-01

    Denmark is a small Northern European country with an extensive welfare state and a strong commitment to maintaining a universal healthcare system. Like the other countries in the Nordic region, Denmark has a long tradition of democratically governed local and regional governments with extensive responsibilities in organizing welfare state services. The Danish healthcare system has demonstrated an ability to increase productivity, while at the same time maintaining a high level of patient satisfaction. Ongoing reforms have contributed to these results, as well as a firm commitment to innovation and coordination. Regions and municipalities in Denmark are governed by directly elected democratic councils. The Danish case is thus an example of democratic decentralization, but within a framework of national coordination and fiscal control. In spite of the difference in size and historical traditions there are also many similarities between Canada and Denmark, particularly in terms of health and social policy goals and aspirations, and in terms of the commitment to a comprehensive, universal healthcare system. These similarities provide interesting opportunities for comparison.

  2. Region counting algorithm based on region labeling automaton

    NASA Astrophysics Data System (ADS)

    Yang, Sudi; Gu, Guoqing

    2007-12-01

    Region counting is a conception in computer graphics and image analysis, and it has many applications in medical area recently. The existing region-counting algorithms are almost based on filling method. Although filling algorithm has been improved well, the speed of these algorithms used to count regions is not satisfied. A region counting algorithm based on region labeling automaton is proposed in this paper. By tracing the boundaries of the regions, the number of the region can be obtained fast. And the proposed method was found to be fastest and requiring less memory.

  3. Star formation enhancement characteristics in interacting galaxies

    NASA Astrophysics Data System (ADS)

    Zaragoza-Cardiel, J.; Beckman, J. E.; Font, J.; Camps-Fariña, A.; García-Lorenzo, B.; Erroz-Ferrer, S.

    2015-02-01

    We have observed 12 interacting galaxies using the Fabry-Perot interferometer GHαFaS (Galaxy Hα Fabry-Perot system) on the 4.2m William Herschel Telescope (La Palma). We have extracted the physical properties (sizes, Hα luminosity and velocity dispersion) of 236 HII regions for the full sample of interacting galaxies. We have derived the physical properties of 664 HII regions for a sample of 28 isolated galaxies observed with the same instrument in order to compare both populations of HII regions, finding that there are brighter and denser star forming regions in the interacting galaxies compared with the isolated galaxies sample.

  4. [Ultrasound and regional anaesthesia].

    PubMed

    Delaunay, L; Plantet, F; Jochum, D

    2009-02-01

    The use of ultrasound is the latest major evolution in regional anaesthesia. Review of available literature shows significant changes in clinical practice. Ultrasound guidance allows the visualization of anatomical variations or unsuspected intraneural injections, reduces the volume of local anaesthetic injections and confirms correct local anaesthetic distribution or catheter placement. No study has found a statistical difference in success rates and safety because all studies were underpowered. However, the ability to visualize an invasive procedure that has been performed blindly in the past is an undeniable progress in terms of safety. The necessity to be familiar with the machine and the learning curve can be repulsive. The aim of this article is to demystify ultrasound guidance by explaining the fundamentals of the clinical use of ultrasound. With the help of different chapters, the authors explain the different adjustments and possible artefacts and give easy solutions for the use of bedside ultrasound. Training is essential and can be performed on manikins or training phantom. For each region the main anatomical landmarks are explained. One must be familiar with several imaging techniques: short axis (transverse) or long axis (longitudinal) nerve imaging, in-plane or out-of-plane imaging and hydrolocalization. Viewing the needle's tip position during its progression remains the main safety endpoint. Therefore, electrical nerve stimulation and ultrasound guidance should be combined, especially for beginners, to confirm proximity to neural structures and to help in case of difficulty. Optimizing safety and clinical results must remain a key priority in regional anaesthesia. Finally, specific regulations concerning the transducers are described. Paediatric specificities are also mentioned.

  5. Regional river sulfur runoff

    SciTech Connect

    Husar, R.B.; Husar, J.D.

    1985-01-20

    The water and sulfur runoff data for 54 large river basins were assembled, covering 65% of the nondesert land area of the world. The sulfur concentration ranges from 0.5 mg S/L for the West African rivers Niger and Volta to 100 mg S/L in the Colorado River; the world average is 3.2 mg S/L. The concentrations in central and eastern Europe as well as central and eastern North America exceed 8 mg S/L. The sulfur runoff density is also highest in the river basins over these industrialized regions, exceeding 2 g S/m/sup 2//yr. However, high sulfur runoff density in excess of 3 g S/m/sup 2//yr is also measured over the Pacific islands New Zealand and New Guinea and the archipelagos of Indonesia and the Philippines. The natural background sulfur runoff was estimated by assuming that South America, Africa, Australia, and the Pacific Islands are unperturbed by man and that the average river sulfur concentration is in the range 1--3 mg S/L. Taking these background concentration values, the man-induced sulfur runoff for Europe ranges between 2 and 8 times the natural flow, and over North America, man's contribution ranges between 1 and 5 times the natural runoff. The global sulfur flow from nondesert land to the oceans and the Caspian Sea is estimated as 131 Tg S/yr, of which 46--85 Tg S/yr is attributed to natural causes. The regional river sulfur runoff pattern discussed in this paper does not have enough spatial resolution to be directly applicable to studies of the environmental effects of man-induced sulfur flows. However, it points to the continental-size regions where those perturbations are most evident and to the magnitude of the perturbations as expressed in units of the natural flows.

  6. Regional river sulfur runoff

    NASA Astrophysics Data System (ADS)

    Husar, Rudolf B.; Husar, Janja Djukic

    1985-01-01

    The water and sulfur runoff data for 54 large river basins were assembled, covering 65% of the nondesert land area of the world. The sulfur concentration ranges from 0.5 mg S/L for the West African rivers Niger and Volta to 100 mg S/L in the Colorado River; the world average is 3.2 mg S/L. The concentrations in central and eastern Europe as well as central and eastern North America exceed 8 mg S/L. The sulfur runoff density is also highest in the river basins over these industrialized regions, exceeding 2 g S/m2/yr. However, high sulfur runoff density in excess of 3 g S/m2/yr is also measured over the Pacific islands New Zealand and New Guinea and the archipelagos of Indonesia and the Philippines. The natural background sulfur runoff was estimated by assuming that South America, Africa, Australia, and the Pacific Islands are unperturbed by man and that the average river sulfur concentration is in the range 1-3 mg S/L. Taking these background concentration values, the man-induced sulfur runoff for Europe ranges between 2 and 8 times the natural flow, and over North America, man's contribution ranges between 1 and 5 times the natural runoff. The global sulfur flow from nondesert land to the oceans and the Caspian Sea is estimated as 131 Tg S/yr, of which 46-85 Tg S/yr is attributed to natural causes. The regional river sulfur runoff pattern discussed in this paper does not have enough spatial resolution to be directly applicable to studies of the environmental effects of man-induced sulfur flows. However, it points to the continental-size regions where those perturbations are most evident and to the magnitude of the perturbations as expressed in units of the natural flows.

  7. Southeast Regional Experiment Station

    NASA Astrophysics Data System (ADS)

    1994-08-01

    This is the final report of the Southeast Regional Experiment Station project. The Florida Solar Energy Center (FSEC), a research institute of the University of Central Florida (UCF), has operated the Southeast Regional Experiment Station (SE RES) for the US Department of Energy (DOE) since September 1982. Sandia National Laboratories, Albuquerque (SNLA) provides technical program direction for both the SE RES and the Southwest Regional Experiment Station (SW RES) located at the Southwest Technology Development Institute at Las Cruces, New Mexico. This cooperative effort serves a critical role in the national photovoltaic program by conducting system evaluations, design assistance and technology transfer to enhance the cost-effective utilization and development of photovoltaic technology. Initially, the research focus of the SE RES program centered on utility-connected PV systems and associated issues. In 1987, the SE RES began evaluating amorphous silicon (a-Si) thin-film PV modules for application in utility-interactive systems. Stand-alone PV systems began receiving increased emphasis at the SE RES in 1986. Research projects were initiated that involved evaluation of vaccine refrigeration, water pumping and other stand-alone power systems. The results of this work have led to design optimization techniques and procedures for the sizing and modeling of PV water pumping systems. Later recent research at the SE RES included test and evaluation of batteries and charge controllers for stand-alone PV system applications. The SE RES project provided the foundation on which FSEC achieved national recognition for its expertise in PV systems research and related technology transfer programs. These synergistic products of the SE RES illustrate the high visibility and contributions the FSEC PV program offers to the DOE.

  8. Higher Education and Regional Development.

    ERIC Educational Resources Information Center

    Neave, Guy

    1979-01-01

    The effect that the university has upon its region and the issue of regional control of higher education are examined. A definition of regional development is offered and regional planning, relevant research, cultural mobilization, and the Jacobin university are described. (Author/MLW)

  9. MC-27 Noachis Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-27 quadrangle, Noachis region of Mars. Heavily cratered highlands dominate the Noachis quadrangle. The northeastern part is marked by the western half of the ancient large Hellas basin, defined by a rim of rugged mountain blocks that surrounds a nearly circular expanse of light-colored plains. The southeastern part is marked by the Peneus caldera and part of the Amphitrites shield volcano and associated ridged plains that may be basaltic flows. Latitude range -65 to -30 degrees, longitude range -60 to 0 degrees.

  10. MC-8 Amazonis Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-8 quadrangle, Amazonis region of Mars. The central part, which is dominated by light-colored, relatively smooth to hummocky plains of Amazonis Planitia, is partly bounded to the east by the western flank of the largest known volcano in the solar system, Olympus Mons, and its associated aureole deposits. Moderately cratered knobby terrain is west of the plains of Amazonis Planitia. Latitude range 0 to 30 degrees, longitude range 135 to 180 degrees.

  11. MC-15 Elysium Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-15 quadrangle, Elysium region of Mars. The Elysium quadrangle includes relatively smooth lowland plains immediately north of the more cratered highlands. The plains are interrupted on the northwest by two large shield volcanoes, Elysium Mons and Albor Tholus. The plains are also marked by an elongate crater, Orcus Patera, at the east boundary and a band of knobby terrain that extends northeastward through the eastern part. Latitude range 0 to 30 degrees, longitude range -180 to -135 degrees.

  12. MC-18 Coprates Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-18 quadrangle, Coprates region of Mars. Moderately cratered and faulted highland ridged plains in the northern and southern parts are cut by the prominent Valles Marineris chasma system, which reaches depths of 10 km and extends in an east-southeast direction for about 2,500 km across the quadrangle. The long, central canyons appear to be large, fault-bounded rifts, whereas some of the isolated, northern canyons are the sources of large outflow channels. Latitude range -30 to 0 degrees, longitude range 45 to 90 degrees.

  13. MC-21 Iapygia Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-21 quadrangle, Iapygia region of Mars. Heavily cratered and in places dissected highlands dominate the Iapygia quadrangle. The west-central part is marked by a large impact crater, Huygens. Huygens is an ancient remnant of the many large impact events that occurred during the period of heavy bombardment. The southern one-third is characterized by mountainous and knobby terrain of the northern rim of the enormous Hellas impact basin. Latitude range -30 to 0 degrees, longitude range -90 to -45 degrees.

  14. MC-29 Eridania Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-29 quadrangle, Eridania region of Mars. The quadrangle is dominated by heavily cratered highlands, with some moderately cratered plains in the central part and large ridge systems in the southern part. The west-central part is marked by a large impact crater, Kepler. Kepler is an ancient remnant of the many large impact events that occurred during the period of heavy bombardment. Latitude range -65 to 30 degrees, longitude range -180 to -120 degrees.

  15. Complex regional pain syndrome

    PubMed Central

    Sebastin, Sandeep J

    2011-01-01

    Complex regional pain syndrome (CRPS) previously known as reflex sympathetic dystrophy is a chronic neurological disorder involving the limbs characterized by disabling pain, swelling, vasomotor instability, sudomotor abnormality, and impairment of motor function. CRPS is not uncommon after hand surgery and may complicate post-operative care. There is no specific diagnostic test for CRPS and the diagnosis is based on history, clinical examination, and supportive laboratory findings. Recent modifications to diagnostic criteria have enabled clinicians to diagnose this disease more consistently. This review gives a synopsis of CRPS and discusses the diagnosis, pathophysiology, and treatment options based on the limited evidence in the literature. PMID:22022040

  16. Colorado Regional Faults

    SciTech Connect

    Hussein, Khalid

    2012-02-01

    Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Originator: Colorado Geological Survey (CGS) Publication Date: 2012 Title: Regional Faults Edition: First Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science, University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains the regional faults of Colorado Spatial Domain: Extent: Top: 4543192.100000 m Left: 144385.020000 m Right: 754585.020000 m Bottom: 4094592.100000 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal Code: 80309-0216 Country: USA Contact Telephone: 303-492-6782 Spatial Reference Information: Coordinate System: Universal Transverse Mercator (UTM) WGS’1984 Zone 13N False Easting: 500000.00000000 False Northing: 0.00000000 Central Meridian: -105.00000000 Scale Factor: 0.99960000 Latitude of Origin: 0.00000000 Linear Unit: Meter Datum: World Geodetic System 1984 (WGS ’984) Prime Meridian: Greenwich Angular Unit: Degree Digital Form: Format Name: Shape file

  17. Neptune's south polar region

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This image of Neptune's south polar region was obtained by the NASA Voyager narrow-angle camera on Aug. 23, 1989, when it was at a distance of 25 million kilometers (1.6 million miles). The smallest cloud features are 45 kilometers (28 miles) in diameter. The image shows the discovery of shadows in Neptune's atmosphere, shadows cast onto a deep cloud bank by small elevated clouds. Located at about 68 degrees south latitude, they are the first cloud shadows ever seen by the Voyager on any planet. The dark regions adjacent to the small bright clouds are believed to be shadows, because they are on the side of the cloud that is opposite to the incoming sunlight and because they lengthen in places where the sun lies closer to the horizon. Estimates of the height of these discrete clouds above the underlying cloud bank can be obtained by careful analysis of this data. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.

  18. Transient regional osteoporosis.

    PubMed

    Cano-Marquina, Antonio; Tarín, Juan J; García-Pérez, Miguel-Ángel; Cano, Antonio

    2014-04-01

    Transient regional osteoporosis (TRO) is a disease that predisposes to fragility fracture in weight bearing joints of mid-life women and men. Pregnant women may also suffer the process, usually at the hip. The prevalence of TRO is lower than the systemic form, associated with postmenopause and advanced age, but may be falsely diminished by under-diagnosis. The disease may be uni- or bilateral, and may migrate to distinct joints. One main feature of TRO is spontaneous recovery. Pain and progressive limitation in the functionality of the affected joint(s) are key symptoms. In the case of the form associated with pregnancy, difficulties in diagnosis derive from the relatively young age at presentation and from the clinical overlapping with the frequent aches during gestation. Densitometric osteoporosis in the affected region is not always present, but bone marrow edema, with or without joint effusion, is detected by magnetic resonance. There are not treatment guidelines, but the association of antiresorptives to symptomatic treatment seems to be beneficial. Surgery or other orthopedic interventions can be required for specific indications, like hip fracture, intra-medullary decompression, or other.

  19. Regional flood probabilities

    USGS Publications Warehouse

    Troutman, B.M.; Karlinger, M.R.

    2003-01-01

    The T-year annual maximum flood at a site is defined to be that streamflow, that has probability 1/T of being exceeded in any given year, and for a group of sites the corresponding regional flood probability (RFP) is the probability that at least one site will experience a T-year flood in any given year. The RFP depends on the number of sites of interest and on the spatial correlation of flows among the sites. We present a Monte Carlo method for obtaining the RFP and demonstrate that spatial correlation estimates used in this method may be obtained with rank transformed data and therefore that knowledge of the at-site peak flow distribution is not necessary. We examine the extent to which the estimates depend on specification of a parametric form for the spatial correlation function, which is known to be nonstationary for peak flows. It is shown in a simulation study that use of a stationary correlation function to compute RFPs yields satisfactory estimates for certain nonstationary processes. Application of asymptotic extreme value theory is examined, and a methodology for separating channel network and rainfall effects on RFPs is suggested. A case study is presented using peak flow data from the state of Washington. For 193 sites in the Puget Sound region it is estimated that a 100-year flood will occur on the average every 4,5 years.

  20. Warm and Dense Molecular Gas in the N 159 Region: 12CO J = 4-3 and 13CO J = 3-2 Observations with NANTEN2 and ASTE

    NASA Astrophysics Data System (ADS)

    Mizuno, Yoji; Kawamura, Akiko; Onishi, Toshikazu; Minamidani, Tetsuhiro; Muller, Erik; Yamamoto, Hiroaki; Hayakawa, Takahiro; Mizuno, Norikazu; Mizuno, Akira; Stutzki, Jürgen; Pineda, Jorge L.; Klein, Uli; Bertoldi, Frank; Koo, Bon-Chul; Rubio, Monica; Burton, Michael; Benz, Arnold; Ezawa, Hajime; Yamaguchi, Nobuyuki; Kohno, Kotaro; Hasegawa, Tetsuo; Tatematsu, Ken'ichi; Ikeda, Masafumi; Ott, Jürgen; Wong, Tony; Hughes, Annie; Meixner, Margaret; Indebetouw, Remy; Gordon, Karl D.; Whitney, Barbara; Bernard, Jean-Philippe; Fukui, Yasuo

    2010-02-01

    New 12CO J = 4-3 and 13CO J = 3-2 observations of the N 159 region, an active site of massive star formation in the Large Magellanic Cloud, have been made with the NANTEN2 and ASTE submillimeter telescopes, respectively. The 12CO J = 4-3 distribution is separated into three clumps, each associated with N 159 W, N 159 E, and N 159 S. These new measurements toward the three clumps are used in coupled calculations of molecular rotational excitation and line radiation transfer, along with other transitions of the 12CO J = 1-0, J = 2-1, J = 3-2, and J = 7-6 as well as the isotope transitions of 13CO J = 1-0, J = 2-1, J = 3-2, and J = 4-3. The 13CO J = 3-2 data were newly taken for the present work. The temperatures and densities were found to be ˜70-80 K and ˜3 × 10³ cm-3 in N 159 W and N 159 E, and ˜30 K and ˜1.6 × 10³ cm-3 in N 159 S. These results were compared with the star-formation activity based on data of young stellar clusters and HII regions as well as midinfrared emission obtained with the Spitzer MIPS. The N 159 E clump is associated with cluster(s) embedded, as observed at 24μm by the Spitzer MIPS, and the derived high temperature, 80 K, is interpreted as being heated by these sources. The N 159 E clump is likely to be responsible for a dark lane in a large HII region by dust extinction. On the other hand, the N 159 W clump is associated with clusters embedded mainly toward the eastern edge of the clump only. These clusters show offsets of 20''-40'' from the 12CO J = 4-3 peak, and are probably responsible for heating indicated by the derived high temperature, 70 K. The N 159 W clump exhibits no sign of star formation toward the 12CO J = 4-3 peak position and its western region that shows enhanced R4-3/1-0 and R3-2/1-0 ratios. We therefore suggest that the N 159 W peak represents a pre-star-cluster core of ˜105Modot which deserves further detailed studies. The N 159 S clump shows little sign of star formation, as is consistent with the lower

  1. MC-28 Hellas Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-28 quadrangle, Hellas region of Mars. The northwestern part includes the eastern half of the ancient large Hellas basin, defined by a rim of rugged mountain blocks that surrounds a nearly circular expanse of light-colored plains. The southwestern part is marked by part of the Amphitrites shield volcano and associated ridged plains that may be basaltic lava flows. The northern part includes a low, dissected shield volcano, Hadriaca Patera, and associated plains that may be basaltic lava flows. These plains are dissected in places by large sinuous channels. The eastern part is dominated by high-standing heavily cratered highlands, perhaps uplifted by the Hellas impact event. Latitude range -65 to -30 degrees, longitude range -120 to -60 degrees.

  2. MC-25 Thaumasia Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-25 quadrangle, Thaumasia region of Mars. In the northern part, a prominent physiographic feature, Thaumasia plateau, includes a complex array of small- and large-scale faults and ridges and ancient volcanoes. Channel systems, upturned beds, and large troughs occur in places along the southern edge of the plateau. In the southern part, the lowlands that surround the plateau include heavily cratered highland terrain and relatively smooth, low plains. The east-central part is marked by a relatively young large impact crater, Lowell. Lowell is one of several large, relatively young impact events on Mars that followed the period of heavy bombardment. Latitude range -65 to -30 degrees, longitude range 60 to 120 degrees.

  3. MC-17 Phoenicis Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-17 quadrangle, Phoenicis Lacus region of Mars. Two of the four largest shield volcanoes on Mars are within the northwestern part, the south half of Pavonis Mons and Arsia Mons. The eastern part includes Syria and Sinai Plana. Most of the quadrangle forms the Tharsis plateau--the highest plateau on Mars; its elevation, 10 km, is twice that of the Tibetan Plateau, the highest plateau on Earth. Also in the northeastern part is Noctis Labyrinthus, a complex system of fault valleys at the west end of Valles Marineris. The south-central part is marked by the large fault system, Claritas Fossae. Latitude range -30 to 0 degrees, longitude range 90 to 135 degrees.

  4. Strengthening regional safeguards

    SciTech Connect

    Palhares, L.; Almeida, G.; Mafra, O.

    1996-08-01

    Nuclear cooperation between Argentina and Brazil has been growing since the early 1980`s and as it grew, so did cooperation with the US Department of Energy (DOE). The Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) was formed in December 1991 to operate the Common System of Accounting and Control of Nuclear Materials (SCCC). In April 1994, ABACC and the DOE signed an Agreement of Cooperation in nuclear material safeguards. This cooperation has included training safeguards inspectors, exchanging nuclear material measurement and containment and surveillance technology, characterizing reference materials, and studying enrichment plant safeguards. The goal of the collaboration is to exchange technology, evaluate new technology in Latin American nuclear facilities, and strengthen regional safeguards. This paper describes the history of the cooperation, its recent activities, and future projects. The cooperation is strongly supported by all three governments: the Republics of Argentina and Brazil and the United States.

  5. Apsus Vallis Region

    NASA Technical Reports Server (NTRS)

    2004-01-01

    22 May 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows light-toned, windblown ripples on the floors of channels of the Apsus Vallis system. The fluid responsible for forming the valleys is unknown; it might have been water. No primary landforms, other than the channels themselves, have been preserved in a way that would indicate the nature of the fluid that carved the valleys. Apsus Vallis is located just west of the Elysium volcanic region; the area in the picture is located near 35.5oN, 225.6oW. The image covers an area about 3 km (1.9 mi) across and is illuminated by sunlight from the lower left.

  6. Mountain regions in peril

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    The United Nations has declared 2002 the International Year of Mountains (IYM) to bring attention to a number of threats that affect ecosystems and human populations in mountainous and highland regions around the world.“More than half of humanity—3 billion people—relies on mountains for safe, fresh water, water to grow food, to produce electricity to sustain industries and, most important, water to drink,“ said Jacques Diouf, director-general of the U.N. Food and Agriculture Organization, the primary IYM sponsor. “Yet, mountain glaciers, the source of water for many of the world's river systems and people, are melting at unprecedented rates.”

  7. Complex regional pain syndrome

    PubMed Central

    Carr, Emily S.; De La Cerda, Ashley

    2016-01-01

    Complex regional pain syndrome (CRPS) is a neurologic disorder that often results in debilitating chronic pain, but the diagnosis may elude providers as it is one of exclusion. A history of trauma may be elucidated. We report a case of CRPS and review the clinical findings, appropriate workup, and treatment options for the patient. The patient we describe went through an extensive workup before receiving the correct diagnosis. Delay in diagnosis leads to prolonged suffering for the patient and, at times, unnecessary invasive debridement procedures. Raising awareness of this entity may help physicians make the correct diagnosis early, as well as initiate a collaborative effort between neurology, anesthesiology, and dermatology to provide the patient the most favorable outcome. PMID:27365892

  8. Modeling Regional Seismic Waves

    DTIC Science & Technology

    1992-06-29

    AD-A264 002 PL-TR-92-2186 iIIiL NIl$111111IlIlIl DTIC 0i•ELECTE fl MODELING REGIONAL SEISMIC WAVES c U 19 Donald V . Heimberger David G. Harkrider...09 WU BA 6. AU~m~ri(ý) -Contract F19628-90-K-0049 Donald V . Helmberger David G. Harkrider .I. PLIFOitRNIhGI OACANIZATItO’ NANIL(ý.) ANO A;ýDOREý(eS...01731-5000 PL-TR-92-2186 Contract Manager: James Lewkowicz/GPEH 11. SUh1Lt 0 ’L.i..TAiY v ~u rLS 1 24. ULr r l,, 4 lI0NAVAIL/jILITY STArTMENT 12b

  9. Reull Vallis Source Region

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site] (Released 1 July 2002) The jumbled, chaotic terrain in this THEMIS image may represent a source region for the Reull Vallis, one of the larger channel systems in the southern hemisphere of Mars. Such regions of chaos are thought to form by the catastrophic release of groundwater. If this was the case, then the water would have flowed down gradient to the south and may have contributed to the formation of the Reull Vallis. The top of the image shows two short segments of channels that are interrupted by the chaos, demonstrating that there was a channel system in place before the ground foundered to produce the chaos. One of the more intriguing features seen among the jumbled blocks are narrow ledges that vaguely resemble bath tub rings in the way they conform to the topography. Two good examples are seen running roughly left-right across the image about a fourth of the way down. At first they appear to be layers protruding from the cliff faces, but upon closer inspection a more ledge-like character is evident. Note how they appear different between the south-facing and north facing cliffs. The occurrence of one of these features on the south-facing interior rim of the largest crater in the image but nowhere else around the rim argues against the idea that the ledges are due to a layer of rock cropping out throughout the landscape. Instead, they appear more like the edges of a layer of sediment that drapes the topography. It is possible that the sediment is mixed with ice and is best preserved in the shadowed portions of the terrain. There is no easy explanation for these unusual features. They represent one more Martian enigma.

  10. Reull Vallis Source Region

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site] (Released 1 July 2002) The jumbled, chaotic terrain in this THEMIS image may represent a source region for the Reull Vallis, one of the larger channel systems in the southern hemisphere of Mars. Such regions of chaos are thought to form by the catastrophic release of groundwater. If this was the case, then the water would have flowed down gradient to the south and may have contributed to the formation of the Reull Vallis. The top of the image shows two short segments of channels that are interrupted by the chaos, demonstrating that there was a channel system in place before the ground foundered to produce the chaos. One of the more intriguing features seen among the jumbled blocks are narrow ledges that vaguely resemble bath tub rings in the way they conform to the topography. Two good examples are seen running roughly left-right across the image about a fourth of the way down. At first they appear to be layers protruding from the cliff faces, but upon closer inspection a more ledge-like character is evident. Note how they appear different between the south-facing and north facing cliffs. The occurrence of one of these features on the south-facing interior rim of the largest crater in the image but nowhere else around the rim argues against the idea that the ledges are due to a layer of rock cropping out throughout the landscape. Instead, they appear more like the edges of a layer of sediment that drapes the topography. It is possible that the sediment is mixed with ice and is best preserved in the shadowed portions of the terrain. There is no easy explanation for these unusual features. They represent one more Martian enigma.

  11. The Massive Stellar Population in the Diffuse Ionized Gas of M33

    NASA Technical Reports Server (NTRS)

    Hoopes, Charles G.; Walterbos, Rene A. M.

    1995-01-01

    We compare Far-UV, H alpha, and optical broadband images of the nearby spiral galaxy M33, to investigate the massive stars associated with the diffuse ionized gas. The H-alpha/FUV ratio is higher in HII regions than in the DIG, possibly indicating that an older population ionizes the DIG. The broad-band colors support this conclusion. The HII region population is consistent with a young burst, while the DIG colors resemble an older population with constant star formation. Our results indicate that there may be enough massive field stars to ionize the DIG, without the need for photon leakage from HII regions.

  12. Lots of Small Stars Born in Starburst Region

    NASA Astrophysics Data System (ADS)

    1999-10-01

    will quickly affect their environment, but how much? At this moment, nobody knows for sure what determines the actual masses of individual stars that are formed in a very massive and turbulent gas cloud, although some ideas can now be tested with these new observations. The NGC 3603 region The new VLT observations are the key part of a larger research programme that also includes observations of the stellar cluster in the famous Tarantula Nebula in the Large Magellanic Cloud (LMC) with the NICMOS instrument on the Hubble Space Telescope (HST), as well as adaptive optics observations with ground-based telescopes of more quiescent, star-forming regions in the Galaxy. However, the team considered the starburst region NGC 3603 as the best target for this kind of investigation. It is situated in the far southern constellation Carina (The Keel) and can only be observed from the South. Moreover, such a study has to focus on the densest part of the cluster that can only be resolved with a very sensitive infrared (IR) instrument under the best seeing conditions. The VLT ANTU telescope and the multi-mode ISAAC facility are ideally suited for this purpose. NGC 3603 is located in the Carina spiral arm in the Milky Way galaxy at a distance of about 20,000 light-years (6 - 7 kpc). It is the only massive, galactic "HII-region" (so denoted by astronomers because part of its hydrogen is ionized) in which a central cluster of strongly UV-radiating stars of types "O" and "B" that ionize the nebula can be studied at visual and near-infrared wavelengths. This is because the line-of-sight is reasonably free of dust in this direction; the dimming in near-infrared radiation due to intervening matter between the nebula and us is only about a factor of 2 (contrary to 80 in visible light). The total mass of the hot O- and B-stars in NGC 3603 is over 2000 solar masses. Together, the more than fifty heavy and bright O-stars in NGC 3603 have about 100 times the ionizing power of the well

  13. Regional brain hypometabolism is unrelated to regional amyloid plaque burden

    PubMed Central

    Altmann, Andre; Ng, Bernard; Landau, Susan M.; Jagust, William J.

    2015-01-01

    See Sorg and Grothe (doi:10.1093/brain/awv302) for a scientific commentary on this article. In its original form, the amyloid cascade hypothesis of Alzheimer’s disease holds that fibrillar deposits of amyloid are an early, driving force in pathological events leading ultimately to neuronal death. Early clinicopathological investigations highlighted a number of inconsistencies leading to an updated hypothesis in which amyloid plaques give way to amyloid oligomers as the driving force in pathogenesis. Rather than focusing on the inconsistencies, amyloid imaging studies have tended to highlight the overlap between regions that show early amyloid plaque signal on positron emission tomography and that also happen to be affected early in Alzheimer’s disease. Recent imaging studies investigating the regional dependency between metabolism and amyloid plaque deposition have arrived at conflicting results, with some showing regional associations and other not. We extracted multimodal neuroimaging data from the Alzheimer’s disease neuroimaging database for 227 healthy controls and 434 subjects with mild cognitive impairment. We analysed regional patterns of amyloid deposition, regional glucose metabolism and regional atrophy using florbetapir (18F) positron emission tomography, 18F-fluordeoxyglucose positron emission tomography and T1-weighted magnetic resonance imaging, respectively. Specifically, we derived grey matter density and standardized uptake value ratios for both positron emission tomography tracers in 404 functionally defined regions of interest. We examined the relation between regional glucose metabolism and amyloid plaques using linear models. For each region of interest, correcting for regional grey matter density, age, education and disease status, we tested the association of regional glucose metabolism with (i) cortex-wide florbetapir uptake; (ii) regional (i.e. in the same region of interest) florbetapir uptake; and (iii) regional florbetapir uptake

  14. Regional brain hypometabolism is unrelated to regional amyloid plaque burden.

    PubMed

    Altmann, Andre; Ng, Bernard; Landau, Susan M; Jagust, William J; Greicius, Michael D

    2015-12-01

    In its original form, the amyloid cascade hypothesis of Alzheimer's disease holds that fibrillar deposits of amyloid are an early, driving force in pathological events leading ultimately to neuronal death. Early clinicopathological investigations highlighted a number of inconsistencies leading to an updated hypothesis in which amyloid plaques give way to amyloid oligomers as the driving force in pathogenesis. Rather than focusing on the inconsistencies, amyloid imaging studies have tended to highlight the overlap between regions that show early amyloid plaque signal on positron emission tomography and that also happen to be affected early in Alzheimer's disease. Recent imaging studies investigating the regional dependency between metabolism and amyloid plaque deposition have arrived at conflicting results, with some showing regional associations and other not. We extracted multimodal neuroimaging data from the Alzheimer's disease neuroimaging database for 227 healthy controls and 434 subjects with mild cognitive impairment. We analysed regional patterns of amyloid deposition, regional glucose metabolism and regional atrophy using florbetapir ((18)F) positron emission tomography, (18)F-fluordeoxyglucose positron emission tomography and T1-weighted magnetic resonance imaging, respectively. Specifically, we derived grey matter density and standardized uptake value ratios for both positron emission tomography tracers in 404 functionally defined regions of interest. We examined the relation between regional glucose metabolism and amyloid plaques using linear models. For each region of interest, correcting for regional grey matter density, age, education and disease status, we tested the association of regional glucose metabolism with (i) cortex-wide florbetapir uptake; (ii) regional (i.e. in the same region of interest) florbetapir uptake; and (iii) regional florbetapir uptake while correcting in addition for cortex-wide florbetapir uptake. P-values for each setting

  15. Landslides of Palestinian Region

    NASA Astrophysics Data System (ADS)

    Alwahsh, H.

    2013-12-01

    Natural disasters are extreme sudden events caused by environmental and natural actors that take away the lives of many thousands of people each year and damage large amount of properties. They strike anywhere on earth, often without any warning. A risk maps of natural disaster are very useful to identify the places that might be adversely affected in the event of natural disaster. The earthquakes are one of natural disaster that have the greatest hazards and will cause loss of life and properties due to damaging the structures of building, dams, bridges. In addition, it will affect local geology and soil conditions. The site effects play an important role in earthquake risk because of its amplification or damping simulation. Another parameter in developing risk map is landslide, which is also one of the most important topics in site effect hazards. Palestine region has been suffering landslide hazards because of the topographical and geological conditions of this region. Most Palestine consists of mountainous area, which has great steep slopes and the type of soil is mainly grayish to yellowish silty clay (Marl Soil). Due to the above mentioned factors many landslides have been occurred from Negev south to the northern borders of Palestine. An example of huge and destruction landslide in a Palestine authority is the landslide in the White Mountain area in the city of Nablus, which occurred in 1997. The geotechnical and geophysical investigation as well as slope stability analysis should be considered in making landslide maps that are necessary to develop risk levels of the natural disaster. Landslides occurred in slopes that are created naturally or by human beings. Failure of soil mass occurs, and hence landslide of soil mass happen due to sliding of soil mass along a plane or curved surface. In general, the slopes become unstable when the shear stresses (driving force) generated in the soil mass exceed the available shearing resistance on the rupture surface

  16. USArray Regional Phase Analysis

    NASA Astrophysics Data System (ADS)

    Buehler, J. S.; Shearer, P. M.

    2014-12-01

    The regional Pn and Sn phases, which are typically described as headwaves that propagate in the uppermost mantle, are sensitive to heterogeneities in the mantle lid and complement other seismic studies with poorer vertical resolution at this depth. We have experimented with a variety of approaches to image the velocity structure and anisotropy in the western U.S., starting with separate Pn and Sn time-term tomographies, but also localized cross-correlation and stacking approaches that benefit from the regular USArray station arrangement. Later we combined the data sets for joint Pn-Sn inversions and the resulting Vp/Vs maps provide further insight into the nature of the seismic anomalies. Now that USArray has reached the east coast, we are updating our models to include the cumulative station footprint. The sparser source distribution in the eastern U.S., and the resulting longer ray paths, provide new challenges and justify the inclusion of additional parameters that account for the velocity gradient in the mantle lid. Our results show generally higher Pn velocities in the eastern U.S., but we observe patches of lower velocities around the New Madrid seismic zone and below the eastern Appalachians. We find that the Pn fast axes generally do not agree with SKS splitting orientations, suggesting significant vertical changes in anisotropy in the upper mantle. For example, the circular pattern of the fast polarization direction of SKS in the western U.S. is much less pronounced in the Pn results, and in the eastern U.S. the dominant Pn fast direction is approximately north-south, whereas the SKS fast polarizations are oriented roughly parallel to the absolute plate motion direction. Since Pn and Sn travel through the crust, they can provide additional information on crustal thickness. In several regions our results and estimates from receiver function studies are inconsistent. For example, beneath the Colorado Plateau our crustal thickness estimates are about 35-40 km

  17. A Regional Resource: Appalachian Campuses

    ERIC Educational Resources Information Center

    Roesch, Harry

    1975-01-01

    An Appalachian Regional Commission survey of 180 institutions of higher education in the Appalachian Region pinpoints which institutions offer technical assistance to state and local governments and officals. (Author)

  18. Region 6 Targeted Brownfields Assessment

    EPA Pesticide Factsheets

    A Target Brownfields Assessment (TBA) is a free service the EPA Region 6 Brownfields Team provides to communities to support their eligible brownfields projects. Region 6 consists of Arkansas, Louisiana, new Mexico, Oklahoma, and Texas.

  19. A Regional Resource: Appalachian Campuses

    ERIC Educational Resources Information Center

    Roesch, Harry

    1975-01-01

    An Appalachian Regional Commission survey of 180 institutions of higher education in the Appalachian Region pinpoints which institutions offer technical assistance to state and local governments and officals. (Author)

  20. Sudurnes Regional Heating Corp.

    SciTech Connect

    Lienau, P.J.

    1996-11-01

    The Svartsengi geothermal area is close to the town of Grindavik on the Rekjanes peninsula and is part of an active fissure swarm, lined with crater-rows and open fissures and faults. The high-temperature area has an area of 2 sq. km and shows only limited signs of geothermal activity at the surface. The reservoir, however, contains lots of energy and at least 8 wells supply the Svartsengi Power Plant with steam. The steam is not useable for domestic heating purposes so that heat exchangers are used to heat cold groundwater with the steam. Some steam is also used for producing 16.4 MW{sub e} of electrical power. The article shows the distribution system piping hot water to nine towns and the Keflavik International Airport. The effluent brine from the Svartsengi Plant is disposed of into a surface pond, called the Blue Lagoon, popular to tourists and people suffering from psoriasis and other forms of eczema seeking therapeutic effects from the silica rich brine. This combined power plant and regional district heating system (cogeneration) is an interesting and unique design for the application of geothermal energy.

  1. Active region flows

    NASA Technical Reports Server (NTRS)

    Foukal, Peter

    1987-01-01

    A wide range of observations has shown that active region phenomena in the photospheric, chromospheric and coronal temperature regimes are dynamical in nature. At the photosphere, recent observations of full line profiles place an upper limit of about + or - 20/msec on any downflows at supergranule cell edges. Observations of the full Stokes 5 profiles in the network show no evidence for downflows in magnetic flux tubes. In the area of chromospheric dynamics, several models were put forward recently to reproduce the observed behavior of spicules. However, it is pointed out that these adiabatic models do not include the powerful radiative dissipation which tend to damp out the large amplitude disturbances that produce the spicular acceleration in the models. In the corona, loop flows along field lines clearly transport mass and energy at rates important for the dynamics of these structures. However, advances in understanding the heating and mass balance of the loop structures seem to require new kinds of observations. Some results are presented using a remote sensing diagnostic of the intensity and orientation of macroscopic plasma electric fields predicted by models of reconnective heating and also wave heating.

  2. On Titan's Xanadu region

    NASA Astrophysics Data System (ADS)

    Brown, Robert H.; Barnes, Jason W.; Melosh, H. Jay

    2011-08-01

    A large, circular marking ˜1800 km across is seen in near-infrared images of Titan. The feature is centered at 10°S, 120°W on Titan, encompasses much of Titan's western Xanadu region, and has an off-center, quasi-circular, inner margin about 700 km across, with lobate outer margins extending 200-500 km from the inner margin. On the feature's southern flank is Tui Regio, an area that has very high reflectivity at 5 μm, and is hypothesized to exhibit geologically recent cryovolcanic flows (Barnes, J.W. et al. [2006]. Geophys. Res. Lett. 33), similar to flows seen in Hotei Regio, a cryovolcanic area whose morphology may be controlled by pre-existing, crustal fractures resulting from an ancient impact (Soderblom, L.A. et al. [2009]. Icarus, 204). The spectral reflectivity of the large, circular feature is quite different than that of its surroundings, making it compositionally distinct, and radar measurements of its topography, brightness temperature and volume scattering also suggest that the feature is quite distinct from its surroundings. These and several other lines of evidence, in addition to the feature's morphology, suggest that it may occupy the site of an ancient impact.

  3. Teaching Regional Perspectives in Canada.

    ERIC Educational Resources Information Center

    McCreath, Peter

    1978-01-01

    Defines Canadian regionalism in terms of geographical features and their political, social, and economic implications, rather than in terms of political and provincial boundaries. The significance of regionalism is mentioned as an important topic for Canadian studies. Increasing awareness and acceptance of regional perspectives is presented as an…

  4. Europa Wedge Region

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This image shows an area of crustal separation on Jupiter's moon, Europa. Lower resolution pictures taken earlier in the tour of NASA's Galileo spacecraft revealed that dark wedge-shaped bands in this region are areas where the icy crust has completely pulled apart. Dark material has filled up from below and filled the void created by this separation.

    In the lower left corner of this image, taken by Galileo's onboard camera on December 16, 1997, a portion of one dark wedge area is visible, revealing a linear texture along the trend of the wedge. The lines of the texture change orientation slightly and reflect the fact that we are looking at a bend in the wedge. The older, bright background, visible on the right half of the image, is criss-crossed with ridges. A large, bright ridge runs east-west through the upper part of the image, cutting across both the older background plains and the wedge. This ridge is rough in texture, with numerous small terraces and troughs containing dark material.

    North is to the top of the picture and the sun illuminates the surface from the northwest. This image, centered at approximately 16.5 degrees south latitude and 196.5 degrees west longitude, covers an area approximately 10 kilometers square (about 6.5 miles square). The resolution of this image is about 26 meters per picture element. This image was taken by the solid state imaging system from a distance of 1250 kilometers (750 miles).

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  5. Europa Wedge Region

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This image shows an area of crustal separation on Jupiter's moon, Europa. Lower resolution pictures taken earlier in the tour of NASA's Galileo spacecraft revealed that dark wedge-shaped bands in this region are areas where the icy crust has completely pulled apart. Dark material has filled up from below and filled the void created by this separation.

    In the lower left corner of this image, taken by Galileo's onboard camera on December 16, 1997, a portion of one dark wedge area is visible, revealing a linear texture along the trend of the wedge. The lines of the texture change orientation slightly and reflect the fact that we are looking at a bend in the wedge. The older, bright background, visible on the right half of the image, is criss-crossed with ridges. A large, bright ridge runs east-west through the upper part of the image, cutting across both the older background plains and the wedge. This ridge is rough in texture, with numerous small terraces and troughs containing dark material.

    North is to the top of the picture and the sun illuminates the surface from the northwest. This image, centered at approximately 16.5 degrees south latitude and 196.5 degrees west longitude, covers an area approximately 10 kilometers square (about 6.5 miles square). The resolution of this image is about 26 meters per picture element. This image was taken by the solid state imaging system from a distance of 1250 kilometers (750 miles).

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  6. Venus - Lavinia Region

    NASA Image and Video Library

    1996-10-23

    This image from NASA Magellan spacecraft is centered at approximately 29.6 degrees south latitude and 341 degrees east longitude in the Lavinia Region of Venus. Volcanic vent areas in this part of the plains west of Alpha Regio consist of domes and pits up to nearly 3 kilometers across. Extending eastward these features are sinuous channels, most of which are about 10 kilometers or more long. The channels narrow away from the pits and for most of their lengths are about 1 kilometer in diameter. The nearest planetary analogues for these features are sinuous rilles on the moon. These have been explained as lava channels and/or the result of lava erosion. On Earth lava channels form by downhill drainage of a lava flow leaving a channel behind. Lava may continue to flow in the channel once it has formed. However, lava channels on Earth are normally only a few meters or tens of meters wide. On the other hand, they may be the result of lava erosion. This is a process that only normally occurs to a limited extent on Earth because melting is inhibited by the cool upper layers of the planet. Also, lavas rarely flow turbulently enough to cause mechanical erosion. On Venus the surface materials are already at high temperatures, thus assisting thermal erosion and it is possible that lavas which may flow turbulently are more readily available than on Earth. Resolution of the Magellan data is about 120 meters (400 feet). http://photojournal.jpl.nasa.gov/catalog/PIA00467

  7. Regions. [Africa, Middle East].

    PubMed

    1985-03-01

    This discussion of population focuses on the regions of Africa and the Middle East. In South Africa more white women are working but fewer black women work. The overall result is that the percentage of women who work is declining. Marita de Beer, research liaison executive at the South African Advertising Research Foundation, reports that the female population grew by 31% in the past 10 years while the number of working women has grown by only 11%. Among blacks the female population rose by 36%, but the number of workers among them declined by about 1%. Married women are among the fastest growing groups of working women in South Africa. The most recent estimate of the population of Nigeria is 92 million. According to Professor Vremudia Diejomaoh, Nigeria's population will probably reach 155 million by 2000 with 33% living in urban areas. In Saudi Arabia the Pan Arab Research Center recently completed a census of retail outlets in 3 metropolitan areas: Jeddah, Riyadh, and Dammam. The types of outlets surveyed include large supermarkets, small supermarkets, groceries with and without deep freeze, tobacco shops, meat shop/delis, small cafeterias, large restaurants/hotels, cosmetics shops or perfumeries, camera stores, toy shops, pharmacies, watch and gift shop, newsstands, department store, and appliance outlets. Using the Census of Retail Outlets as a base, Pan Arab Research Center also has a new distribution audit system that will cover 500 outlets. By plotting Arab countries according to their population policies and their current growth rates, it is possible to project where the middle class will grow fastest in the Arab world. The countries that have declining growth rates and strong population programs designed to encourage lower fertility rates among women are Egypt, Tunisia, Morocco, Algeria, and Lebanon. The countries most likely to have a better per capita distribution of resources within this decade are those where governments encourage reductions in

  8. Thinking regionally: narrative, the medical humanities and region.

    PubMed

    Waddington, Keir

    2015-06-01

    Drawing on multiple literatures from history, geography, anthropology, sociology and literature, this essay asks questions about what we mean by region and why narratives of region should matter to the medical humanities. The essay surveys how region can be used as a lens of analysis, exploring the various academic approaches to region and their limitations. It argues that regions are dynamic but also unstable as a category of analysis and are often used uncritically by scholars. In encouraging scholars working in the medical humanities to be aware that regions are not simple objective or analytical boxes, the essay shows how an awareness of region helps challenge metropolitan whiggism and ideas of core and periphery to give a more prominent place to hinterlands, market towns and rural environments. Furthermore, the essay considers how incorporating region into our understanding of illness can offer new insights. It demonstrates the need for scholars to be attuned to the narratives constructed around regions, suggesting that regions can be viewed as discursive formations that provide a frame for understanding both collective and personal ideas of, and responses to, health and illness, disease and healing, to create what Megan Davies calls a more nuanced 'intellectual cartography'. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  9. Emission measure distribution for diffuse regions in solar active regions

    SciTech Connect

    Subramanian, Srividya; Tripathi, Durgesh; Klimchuk, James A.; Mason, Helen E.

    2014-11-01

    Our knowledge of the diffuse emission that encompasses active regions is very limited. In this paper we investigate two off-limb active regions, namely, AR 10939 and AR 10961, to probe the underlying heating mechanisms. For this purpose, we have used spectral observations from Hinode/EIS and employed the emission measure (EM) technique to obtain the thermal structure of these diffuse regions. Our results show that the characteristic EM distributions of the diffuse emission regions peak at log T = 6.25 and the coolward slopes are in the range 1.4-3.3. This suggests that both low- as well as high-frequency nanoflare heating events are at work. Our results provide additional constraints on the properties of these diffuse emission regions and their contribution to the background/foreground when active region cores are observed on-disk.

  10. Near-Infrared spectroscopy of shocked molecular hydrogen in star formation regions

    NASA Astrophysics Data System (ADS)

    Fernandes, Amadeu J. L.

    1993-11-01

    -produced Lyα resonance pumping or by direct UV excitation of H2 from the central HII region and producing higher fluorescent fluxes. We show that the H2 emission can be explained in terms of a model consisting of a C-shock and a PDR. The H2 line ratios are best fitted with a PDR model with parameters: FUV field in the range 102 <= G0 <= 103 and densities n >= 3 × 103 cm-3. We show that the H2 fluorescent emission from both HH 7 and DR 21 is reproduced better with an ortho-to-para ratio of 1.8.

  11. Elementary bipoles of active regions and ephemeral active regions

    NASA Technical Reports Server (NTRS)

    Martin, Sara F.

    1990-01-01

    The general properties of elementary bipoles (EBs), the class of moving magnetic features identified by Frazier (1972) as building blocks of new solar active regions, are described, and variations in their characteristics are illustrated with extensive videomagnetograms obtained at Big Bear Solar Observatory during 1984-1989. Consideration is given to ephemeral active regions consisting of EBs with only one positive and one negative pole, multiple-pole ephemeral regions, reversed-polarity EBs, interactions among EBs and adjacent magnetic features, and the EBs of small and medium active regions. The detection of EBs prior to the appearance of arch filaments confirms the relationship found by Frazier.

  12. NGC 1976 in the Radio Range with the Green Bank Telescope

    NASA Astrophysics Data System (ADS)

    Wilson, Thomas L.; Bania, Thomas M.; Balser, Dana S.

    2015-01-01

    NGC 1976 (Orion A) is the best studied HII region in the Milky Way and therefore it is often used to test models of HII regions. In particular, the radial dependence of the electron temperature is able to distinguish between different models. Optical determinations of electron temperature in the outer regions are affected by scattered light from the center. We have observed the radio recombination line (RRL) and continuum emission near 5 GHz at 4 arc minutes East, West and South of the peak HII region emission in NGC 1976 using the Green Bank Telescope (GBT). The Full Width to Half Power at the observing frequency, 5 GHz, was 2 arc minutes. The result is that the average electron temperature for these offset positions is = 7200 ± 300 K, significantly lower than the electron temperature of the peak position = 8200 ± 300 K, consistent with the HII region model of Wilson et al. (2012).

  13. Regional governance: strategies and disputes in health region management

    PubMed Central

    dos Santos, Adriano Maia; Giovanella, Ligia

    2014-01-01

    OBJECTIVE To analyze the regional governance of the health systemin relation to management strategies and disputes. METHODOLOGICAL PROCEDURES A qualitative study with health managers from 19 municipalities in the health region of Bahia, Northeastern Brazil. Data were drawn from 17 semi-structured interviews of state, regional, and municipal health policymakers and managers; a focus group; observations of the regional interagency committee; and documents in 2012. The political-institutional and the organizational components were analyzed in the light of dialectical hermeneutics. RESULTS The regional interagency committee is the chief regional governance strategy/component and functions as a strategic tool for strengthening governance. It brings together a diversity of members responsible for decision making in the healthcare territories, who need to negotiate the allocation of funding and the distribution of facilities for common use in the region. The high turnover of health secretaries, their lack of autonomy from the local executive decisions, inadequate technical training to exercise their function, and the influence of party politics on decision making stand as obstacles to the regional interagency committee’s permeability to social demands. Funding is insufficient to enable the fulfillment of the officially integrated agreed-upon program or to boost public supply by the system, requiring that public managers procure services from the private market at values higher than the national health service price schedule (Brazilian Unified Health System Table). The study determined that “facilitators” under contract to health departments accelerated access to specialized (diagnostic, therapeutic and/or surgical) services in other municipalities by direct payment to physicians for procedure costs already covered by the Brazilian Unified Health System. CONCLUSIONS The characteristics identified a regionalized system with a conflictive pattern of governance and

  14. An interactive region merging method

    NASA Astrophysics Data System (ADS)

    Wu, Rongteng

    2011-11-01

    The paper presents a novel region merging method based on the interactive information from users. An image firstly is partitioned into homogeneous regions by using an initial segmentation and the regions will be label by taking an interactive scheme. In this scheme, the users only roughly specify the position and main features of the object and background, then any region will belong to non-label region or label region i.e. object or background. A similarity rule is used to guide the merging process with the help of the users' markers. And then the object of interest is extracted from the image. Experiment results show that the proposed method is efficient for us to extract the object of interest from the complex background.

  15. The structure and early evolution of massive star forming regions. Substructure in the infrared dark cloud SDC13

    NASA Astrophysics Data System (ADS)

    McGuire, C.; Fuller, G. A.; Peretto, N.; Zhang, Q.; Traficante, A.; Avison, A.; Jimenez-Serra, I.

    2016-10-01

    Context. Investigations into the substructure of massive star forming regions are essential for understanding the observed relationships between core mass distributions and mass distributions in stellar clusters, differentiating between proposed mechanisms of massive star formation. Aims: We study the substructure in the two largest fragments (i.e. cores) MM1 and MM2, in the infrared dark cloud complex SDC13. As MM1 appears to be in a later stage of evolution than MM2, comparing their substructure provides an insight in to the early evolution of massive clumps. Methods: We report the results of high resolution SMA dust continuum observations towards MM1 and MM2. Combining these data with Herschel observations, we carry out RADMC-3D radiative transfer modelling to characterise the observed substructure. Results: SMA continuum data indicates 4 sub-fragments in the SDC13 region. The nature of the second brightest sub-fragment (B) is uncertain as it does not appear as prominent at the lower MAMBO resolution or at radio wavelengths. Statistical analysis indicates that it is unlikely to be a background source, an AGB star, or the free-free emission of a HII region. It is plausible that B is a runaway object ejected from MM1. MM1, which is actively forming stars, consists of two sub-fragments A and C. This is confirmed by 70 μmHerschel data. While MM1 and MM2 appear quite similar in previous low resolution observations, at high resolution, the sub-fragment at the centre of MM2 (D) is much fainter than sub-fragment at the centre of MM1 (A). RADMC-3D models of MM1 and MM2 are able to reproduce these results, modelling MM2 with a steeper density profile and higher mass than is required for MM1. The relatively steep density profile of MM2 depends on a significant temperature decrease in its centre, justified by the lack of star formation in MM2. A final stellar population for MM1 was extrapolated, indicating a star formation efficiency typical of regions of core and cluster

  16. Regional Climate Tutorial: Assessing Regional Climate Change and Its Impacts

    NASA Astrophysics Data System (ADS)

    Barron, E.; Fisher, A.

    2002-05-01

    Recent scientific progress now enables credible projections of global changes in climate over long time periods. But people will experience global climate change where they live and work, and have difficulty thinking of a future beyond their grandchildren's lifetime. Although the task of projecting climate change and its impacts is far more challenging for regional and relatively near-term time scales, these are the scales at which actions most easily can be taken to moderate negative impacts. This tutorial will summarize what is known about projecting changes in regional climate, and about assessing the impacts for sectors such as forests, agriculture, fresh water quantity and quality, coastal zones, human health, and ecosystems. The Mid-Atlantic Regional Assessment (MARA) is used to provide context and illustrate how adaptation within the region and feedback from other regions influence the impacts that might be experienced.

  17. Global and regional air quality responses to regional CO reductions

    NASA Astrophysics Data System (ADS)

    Fry, M. M.; Adelman, Z.; Dolwick, P.; Jang, C.; West, J. J.

    2011-12-01

    Ozone (O3) precursor emissions influence global and regional air quality and climate through changes in the tropospheric concentrations of O3, methane (CH4), and aerosols. Here we examine the influence of regional carbon monoxide (CO) emissions on air quality by simulating 50% reductions in anthropogenic CO emissions from 10 world regions (Australia/New Zealand, Southeast Asia, East Asia, India, Southern Africa, Northern Africa/Middle East, Former Soviet Union, Europe, South America, and North America), using the global chemical transport model MOZART-4. The IPCC AR5 Representative Concentration Pathway 8.5 (RCP 8.5) emissions inventory for 2005 and global meteorology from the Goddard Earth Observing System Model, version 5 (GEOS-5) for 2004-2005 are used as inputs to MOZART-4, run at 1.9 x 2.5 degree horizontal resolution. Base case global air quality is first simulated for the year 2005, and the resulting distributions of tropospheric O3 and related species are compared with observations. Then CO emission reductions from each of the 10 regions are simulated individually. We quantify global and regional changes in O3 and PM2.5 at the surface and within the troposphere, including the influence of each regional reduction on long-term O3 concentrations via CH4 and the long-range transport of O3 and CO. This analysis shows the sensitivity of global and regional air quality to anthropogenic CO emissions from many world regions, in contrast to previous studies of only a few regions. Beyond this study, these simulations will be used to estimate the net radiative forcing due to CO emission reductions from these world regions.

  18. Eukaryotic ribonucleases HI and HII generate characteristic hydrolytic patterns on DNA–RNA hybrids: further evidence that mitochondrial RNase H is an RNase HII

    PubMed Central

    Pileur, Frédéric; Toulme, Jean-Jacques; Cazenave, Christian

    2000-01-01

    RNase H activities from HeLa cells (either of cytoplasmic or mitochondrial origin), and from mitochondria of beef heart and Xenopus ovaries, have been tested with RNA–DNA substrates of defined length (20 bp) and sequence. Substrates were either blunt-ended, or presented DNA or RNA overhangs. The hydrolysis profiles obtained at early times of the digestion showed a good correlation between the class of RNase H, either type I or II assigned according to biochemical parameters, whatever the organism. Consequently, the pattern of primary cuts can be considered as a signature of the predominant RNase H activity. For a given sequence, hydrolysis profiles obtained are similar, if not identical, for either blunt-ended substrates or those presenting overhangs. However, profiles showed variations depending on the sequence used. Of the three sequences tested, one appears very discriminatory, class I RNases H generating a unique primary cut 3 nt from the 3′ end of the RNA strand, whereas class II RNases H generated two simultaneous primary cuts at 6 and at 8 nt from the 5′ end of the RNA strand. Hydrolysis profiles further confirm the assignation of the mitochondrial RNase H activity from HeLa cells, beef heart and Xenopus oocytes to the class II. PMID:10982891

  19. Regional Hospital Input Price Indexes

    PubMed Central

    Freeland, Mark S.; Schendler, Carol Ellen; Anderson, Gerard

    1981-01-01

    This paper describes the development of regional hospital input price indexes that is consistent with the general methodology used for the National Hospital Input Price Index. The feasibility of developing regional indexes was investigated because individuals inquired whether different regions experienced different rates of increase in hospital input prices. The regional indexes incorporate variations in cost-share weights (the amount an expense category contributes to total spending) associated with hospital type and location, and variations in the rate of input price increases for various regions. We found that between 1972 and 1979 none of the regional price indexes increased at average annual rates significantly different from the national rate. For the more recent period 1977 through 1979, the increase in one Census Region was significantly below the national rate. Further analyses indicated that variations in cost-share weights for various types of hospitals produced no substantial variations in the regional price indexes relative to the national index. We consider these findings preliminary because of limitations in the availability of current, relevant, and reliable data, especially for local area wage rate increases. PMID:10309557

  20. East Texas post oak region

    Treesearch

    Herbert S. Sternitzke

    1967-01-01

    This report summarizes information on forest area and timber volume in a 26-county area designated as the post oak region of east Texas. These counties are on the western fringe of lands capable of supporting productive southern forests. The information here is from the first detailed forest inventory of the region, made during 1965 in cooperation with the Texas...

  1. REGIONAL VULNERABILITY: A CONCEPTUAL FRAMEWORK

    EPA Science Inventory

    Regional vulnerability assessment, or ReVA, is an approach to place-based ecological risk assessment that is currently under development by the Office of Research and Development of the U.S. Environmental Protection Agency (EPA). The assessment is done at the scale of EPA region...

  2. About the REL Pacific Region

    ERIC Educational Resources Information Center

    Regional Educational Laboratory Pacific, 2014

    2014-01-01

    REL Pacific is one of ten Regional Educational Laboratories established and funded by the U.S. Department of Education's Institute of Education Sciences. Their region encompasses approximately 4.9 million square miles and serves seven Pacific island entities, including American Samoa; the Commonwealth of the Northern Mariana Islands; the Federated…

  3. CLIMATE IMPACTS ON REGIONAL WATER

    EPA Science Inventory

    The New England region (including the 6 New England
    states plus upstate New York) offers a very diverse geography,
    matched by an equally diverse economy and human
    population. Livelihoods throughout the region are based
    on service industries that depend heavily on comm...

  4. Regional Early Childhood Policy Review

    ERIC Educational Resources Information Center

    Evans, Judith

    2008-01-01

    The UNESCO-UNICEF joint regional policy review project was launched in September 2006 with the aim to support the countries of Asia-Pacific region in meeting the first goal of Education For All (EFA) on Early Childhood Care and Education (ECCE) by identifying, documenting and sharing good practices as well as constraints and challenges in early…

  5. What's Happening to Regional Policy?

    ERIC Educational Resources Information Center

    Ravenhall, Mark

    2005-01-01

    Back in November, voters in the North East of England overwhelmingly rejected the move towards an elected regional assembly. The scale of the defeat (three to one) of a Government-backed scheme was a rude awakening for the Office of the Deputy Prime Minister and the range of regional agencies created since 1997. After all, it was felt that the…

  6. What's Happening to Regional Policy?

    ERIC Educational Resources Information Center

    Ravenhall, Mark

    2005-01-01

    Back in November, voters in the North East of England overwhelmingly rejected the move towards an elected regional assembly. The scale of the defeat (three to one) of a Government-backed scheme was a rude awakening for the Office of the Deputy Prime Minister and the range of regional agencies created since 1997. After all, it was felt that the…

  7. Training Teachers for Regional Colleges.

    ERIC Educational Resources Information Center

    Hla Myint; And Others

    This report presents alternative plans for training teachers for the newly-established Regional Colleges in Burma. The Regional Colleges are three-year postsecondary institutions designed to train middle level technicians to help increase the production of goods and services needed in the Burmese economy. Concentrating on the Hawaii Community…

  8. Regional Early Childhood Policy Review

    ERIC Educational Resources Information Center

    Evans, Judith

    2008-01-01

    The UNESCO-UNICEF joint regional policy review project was launched in September 2006 with the aim to support the countries of Asia-Pacific region in meeting the first goal of Education For All (EFA) on Early Childhood Care and Education (ECCE) by identifying, documenting and sharing good practices as well as constraints and challenges in early…

  9. MISR Regional VBBE Imagery Overview

    Atmospheric Science Data Center

    2016-08-24

    ... View Data  |  Download Data About this Web Site: Visualizations of select MISR Level 3 data for special regional ... in the northern hemisphere (see the table at right). By design, the images show data for a fixed geographical region, with a fixed ...

  10. MISR Regional SAMUM Imagery Overview

    Atmospheric Science Data Center

    2016-08-24

    ... View Data  |  Download Data About this Web Site: Visualizations of select MISR Level 3 data for special regional ... in the northern hemisphere (see the table at right). By design, the images show data for a fixed geographical region, with a fixed ...

  11. CLIMATE IMPACTS ON REGIONAL WATER

    EPA Science Inventory

    The New England region (including the 6 New England
    states plus upstate New York) offers a very diverse geography,
    matched by an equally diverse economy and human
    population. Livelihoods throughout the region are based
    on service industries that depend heavily on comm...

  12. Identification of USSR Indicator Regions

    NASA Technical Reports Server (NTRS)

    Disler, J.; Breigh, H. (Principal Investigator)

    1980-01-01

    Potential indicator regions were determined by comparing the statistics for barley and wheat at the lowest administrative levels for which published statistics were available. Fourteen were selected for review based on their relative abundances of wheat and barely. These potential indicator regions were grouped according to three conditions that could affect labeling and classification accuracies: (1) high-barley content; (2) presence of barley and spring wheat; and (3) presence of barley and winter wheat. Each region was further evaluated based on the availability of crop calendars, LANDSAT acquisitions, and ancillary data. Based on the relative abundance of wheat and barley and the availability of data, three indicator regions were recommended. Within each region, individual oblasts and/or krays were selected according to segment availability and segment acquisition histories for potential barley separation.

  13. Water deuteration in star-forming regions : Contribution of Herschel/HIFI spectroscopic data

    NASA Astrophysics Data System (ADS)

    Coutens, Audrey

    2012-11-01

    HDO/H2O ratios as well as the D2O/HDO ratios determined in IRAS 16293-2422 enable to constrain the conditions of water formation in this kind of objects and in particular suggest that water would be formed before the gravitational collapse of the cloud. This study was then extended to other solar-type protostars NGC1333 IRAS4A and NGC1333 IRAS4B, for which I estimated the abundances of deuterated water and noticed that an extended absorbing layer also surrounds these sources. The high HDO/H2O ratios determined in IRAS 16293-2422 suggest that mechanisms are required between the Class 0 stage and the comets formation to decrease these isotopic ratios. It is however necessary to study a larger sample of protostars to know if this trend is observed in most of the sources. The HDO abundances obtained in NGC1333 IRAS4A and NGC1333 IRAS4B will consequently be useful to estimate their HDO/H2O ratios. Finally, I also studied deuterated water in protostellar objects more massive and more luminous than solar-type protostars and show here the case of the ultra-compact HII region G34.26+0.15.

  14. About Region 8’s Central Regional Laboratory

    EPA Pesticide Factsheets

    The Region 8 laboratory plays a critical role in protecting people's health and the environment through the analysis of air, water, soil, and biota samples (plant, fish, and occasionally, mammalian tissue).

  15. Magnetic TRAnsition Region Probe (MTRAP)

    NASA Technical Reports Server (NTRS)

    Moore, R. L.; Davis, John; Hathaway, David; Six, N. Frank (Technical Monitor)

    2002-01-01

    MTRAP (Magnetic Transition Region Probe) will reveal the fine-scale physical processes in the Sun's magnetic transition region, the complex layer from the upper photosphere to the upper chromosphere/lower transition region. In the magnetic transition region plasma forces and magnetic forces are of comparable strength, which results in complex interplay of the two, which interplay governs the coupling of the convectively-driven deeper layers to the magnetically-driven upper transition region and inner corona. The fine-scale magnetic structure, processes, and events in the magnetic transition region are key to the genesis of the Sun's entire hot, dynamic outer atmosphere and to the initiation of large eruptive events. MTRAP will be a single spacecraft in Sun-synchronous Earth orbit. Because MTRAP will probe and measure the 3-D structure and dynamics of the magnetic field and plasma in the chromosphere and transition region with unprecedented resolution, the required telescope size and telemetry rates dictate that MTRAP be in Earth orbit, not in deep space. The observations will feature visible and infrared maps of vector magnetic and velocity fields in the magnetic transition region and photosphere. These will have large field of view (greater than 100,000 km), high resolution (greater than 100 km), and high sensitivity (greater than 30 G in transverse field). These observations of the lower atmosphere will be complemented by UV maps of the structure, velocity, and magnetic field (including the full vector field if technically feasible) higher up, in the upper chromosphere and lower transition region. MTRAP will also have an EUV imaging spectrograph observing coronal structure and dynamics in the same field of view with comparable resolution. Specific phenomena to be analyzed include spicules, bright points, jets, the base of plumes, and the triggering of eruptive flares and coronal mass ejections. Additional information is included in the original extended abstract.

  16. Regional strategies for global leadership.

    PubMed

    Ghemawat, Pankaj

    2005-12-01

    The leaders of such global powerhouses as GE, Wal-Mart, and Toyota seem to have grasped two crucial truths: First, far from becoming submerged by the rising tide of globalization, geographic and other regional distinctions may in fact be increasing in importance. Second, regionally focused strategies, used in conjunction with local and global initiatives, can significantly boost a company's performance. The business and economic data reveal a highly regionalized world. For example, trade within regions, rather than across them, drove the surge of international commerce in the second half of the twentieth century. Regionalization is also apparent in foreign direct investment, companies' international sales, and competition among the world's largest multinationals. Harvard Business School Professor Pankaj Ghemawat says that the most successful companies employ five types of regional strategies in addition to--or even instead of--global ones: home base, portfolio, hub, platform, and mandate. Some companies adopt the strategies in sequence, but the most nimble switch from one to another and combine approaches as their markets and businesses evolve. At Toyota, for example, exports from the home base continue to be substantial even as the company builds up an international manufacturing presence. And as Toyota achieves economies of scale and scope with a strong network of hubs, the company also pursues economies of specialization through interregional mandates. Embracing regional strategies requires flexibility and creativity. A company must decide what constitutes a region, choose the most appropriate strategies, and mesh those strategies with the organization's existing structures. In a world that is neither truly global nor truly local, finding ways of coordinating within and across regions can deliver a powerful competitive advantage.

  17. LLNL's Regional Seismic Discrimination Research

    SciTech Connect

    Hanley, W; Mayeda, K; Myers, S; Pasyanos, M; Rodgers, A; Sicherman, A; Walter, W

    1999-07-23

    As part of the Department of Energy's research and development effort to improve the monitoring capability of the planned Comprehensive Nuclear-Test-Ban Treaty international monitoring system, Lawrence Livermore Laboratory (LLNL) is testing and calibrating regional seismic discrimination algorithms in the Middle East, North Africa and Western Former Soviet Union. The calibration process consists of a number of steps: (1) populating the database with independently identified regional events; (2) developing regional boundaries and pre-identifying severe regional phase blockage zones; (3) measuring and calibrating coda based magnitude scales; (4a) measuring regional amplitudes and making magnitude and distance amplitude corrections (MDAC); (4b) applying the DOE modified kriging methodology to MDAC results using the regionalized background model; (5) determining the thresholds of detectability of regional phases as a function of phase type and frequency; (6) evaluating regional phase discriminant performance both singly and in combination; (7) combining steps 1-6 to create a calibrated discrimination surface for each stations; (8) assessing progress and iterating. We have now developed this calibration procedure to the point where it is fairly straightforward to apply earthquake-explosion discrimination in regions with ample empirical data. Several of the steps outlined above are discussed in greater detail in other DOE papers in this volume or in recent publications. Here we emphasize the results of the above process: station correction surfaces and their improvement to discrimination results compared with simpler calibration methods. Some of the outstanding discrimination research issues involve cases in which there is little or no empirical data. For example in many cases there is no regional nuclear explosion data at IMS stations or nearby surrogates. We have taken two approaches to this problem, first finding and using mining explosion data when available, and

  18. Monitoring of Polar Avalanche Region

    NASA Image and Video Library

    2010-03-03

    This image from NASA Mars Reconnaissance Orbiter shows the scarp that demarcates the boundary between layered deposits covering the north polar region and the lower surrounding terrain, which includes sand dunes. Original release date March 3, 2010.

  19. Conformity Adequacy Review: Region 8

    EPA Pesticide Factsheets

    Resources are for air quality and transportation government and community leaders. Information on the adequacy/inadequacy of state implementation plans (SIPs) in EPA Region 3 (CO, MT, ND, SD, UT, WY) is provided here.

  20. Region 9 RTOC Strategic Plan

    EPA Pesticide Factsheets

    The Regional Tribal Operations Committee (RTOC) has developed this Strategic Plan to address the issues the RTOC has identified and the activities the RTOC intends to carry out between October 1, 2015 and September 30, 2017.

  1. Boundary Preserving Dense Local Regions.

    PubMed

    Kim, Jaechul; Grauman, Kristen

    2015-05-01

    We propose a dense local region detector to extract features suitable for image matching and object recognition tasks. Whereas traditional local interest operators rely on repeatable structures that often cross object boundaries (e.g., corners, scale-space blobs), our sampling strategy is driven by segmentation, and thus preserves object boundaries and shape. At the same time, whereas existing region-based representations are sensitive to segmentation parameters and object deformations, our novel approach to robustly sample dense sites and determine their connectivity offers better repeatability. In extensive experiments, we find that the proposed region detector provides significantly better repeatability and localization accuracy for object matching compared to an array of existing feature detectors. In addition, we show our regions lead to excellent results on two benchmark tasks that require good feature matching: weakly supervised foreground discovery and nearest neighbor-based object recognition.

  2. Star Forming Regions in Cassiopeia

    NASA Astrophysics Data System (ADS)

    Kun, M.

    2008-12-01

    This chapter describes the Galactic star forming regions in the constellation Cassiopeia, in the Galactic coordinate range 120° ⪉ l ⪉ 130°, -5° ⪉ b ⪉ 15°. At |b| > 10° the nearby clouds L 1333 and L 1340 are found in this region. The local arm of the Galaxy in Cassiopeia contains only a few star forming regions, smaller and less active than the OB associations of the neighboring Cepheus. Five members of this system, LkHα 198 and its environment, L 1287, L 1293, L 1302/NGC 255, and S 187 are discussed. Several more distant OB associations and giant star forming regions in Cassiopeia are associated with the Perseus arm at 2.0--3.0 kpc. Among these, the Herbig Be star MWC 1080 is discussed in this chapter.

  3. Active Region Release Two CMEs

    NASA Image and Video Library

    Solar material can be seen blowing off the sun in this video captured by NASA’s Solar Dynamics Observatory (SDO) on the night of Feb. 5, 2013. This active region on the sun sent out two coronal ...

  4. A regional technology transfer program

    NASA Technical Reports Server (NTRS)

    Chenery, P. J.

    1972-01-01

    The activities of the NC/STRC are reported. The background and organization of the regional dissemination center, and marketing methods are discussed along with the services provided, and available information resources.

  5. Venus - Landslide in Navka Region

    NASA Image and Video Library

    1996-03-14

    NASA Magellan spacecraft observed remnant landslide deposits apparently resulting from the collapse of volcanic structures. This radar image is centered in the southwestern Navka Region of Venus. http://photojournal.jpl.nasa.gov/catalog/PIA00262

  6. Conformity Adequacy Review: Region 5

    EPA Pesticide Factsheets

    Resources are for air quality and transportation government and community leaders. Information on the conformity SIP adequacy/inadequacy of state implementation plans (SIPs) in EPA Region 5 (IL, IN, MI, OH, WI) is provided here.

  7. Conformity Adequacy Review: Region 2

    EPA Pesticide Factsheets

    Resources are for air quality and transportation government and community leaders. Information on the adequacy/inadequacy of state implementation plans (SIPs) in EPA Region 2 (NJ, NY, PR, VI) is provided here.

  8. Conformity Adequacy Review: Region 1

    EPA Pesticide Factsheets

    Resources are for air quality and transportation government and community leaders. Information on the adequacy/inadequacy of state implementation plans (SIPs) in EPA Region 1 (CT, ME, MA, NH, RI, VT) is provided here.

  9. Conformity Adequacy Review: Region 4

    EPA Pesticide Factsheets

    Resources are for air quality and transportation government and community leaders. Information on the adequacy/inadequacy of state implementation plans (SIPs) in EPA Region 4 (AL, FL, GA, KY, MS, NC, SC, TN) is provided here.

  10. Conformity Adequacy Review: Region 9

    EPA Pesticide Factsheets

    Resources are for air quality and transportation government and community leaders. Information on the adequacy/inadequacy of state implementation plans (SIPs) in EPA Region 9 (AZ, CA, HI, NV, AS, GU) is provided here.

  11. Conformity Adequacy Review: Region 3

    EPA Pesticide Factsheets

    Resources are for air quality and transportation government and community leaders. Information on the adequacy/inadequacy of state implementation plans (SIPs) in EPA Region 3 (DE, DC, MD, PA, VA, WV) is provided here.

  12. Conformity Adequacy Review: Region 6

    EPA Pesticide Factsheets

    Resources are for air quality and transportation government and community leaders. Information on the adequacy/inadequacy of state implementation plans (SIPs) in EPA Region 6 (AR, LA, NM, OK, TX) is provided here.

  13. Conformity Adequacy Review: Region 7

    EPA Pesticide Factsheets

    Resources are for air quality and transportation government and community leaders. Information on the adequacy/inadequacy of state implementation plans (SIPs) in EPA Region 7 (IA, KS, MO, NE) is provided here.

  14. Conformity Adequacy Review: Region 10

    EPA Pesticide Factsheets

    Resources are for air quality and transportation government and community leaders. Information on the adequacy/inadequacy of state implementation plans (SIPs) in EPA Region 10 (AK, ID, OR, WA) is provided here.

  15. MC-10 Lanae Palus Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-10 quadrangle, Lanae Palus region of Mars. The western part is dominated by lava flows of the Tharsis region. The central part includes ridged terrain of Lunae Planum. The west and north borders of Lunae Planum are dissected by the large, relatively young outflow channel, Kasei Vallis, which terminates in Chryse Planitia. Latitude range 0 to 30 degrees, longitude range 45 to 90 degrees.

  16. ESPC Regional Arctic Prediction System

    DTIC Science & Technology

    2014-09-30

    the Navy the capability to conduct short-term (1 week) to extended (2 weeks) coupled weather forecasts for the Arctic region. APPROACH To...sensitivity of the Arctic weather forecast to key numerical parameters; and 5) conduct extensive validation and verification of the coupled system and...SEP 2014 2. REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE ESPC Regional Arctic Prediction System 5a. CONTRACT

  17. Parallel Processing of Region Boundaries.

    DTIC Science & Technology

    1985-11-01

    from A is W, while in the other it is S: the region enclosed by the 40--------A curve AC belongs to includes the area above AC, while that cf C AB ...includes the area to the left of AB . The intersection of the iB regions is the one included by AC while the union is the one included by AB . Thus, C is the

  18. MC-13 Syrtis Major Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-13 quadrangle, Syrtis Major region of Mars. The central part is dominated by dark dust and lava flows of the Syrtis Major Planitia region. These lava flows are partly bounded to the east by a large depression, Isidis basin, which contains smooth plains, and to the west and north by heavily cratered and moderately faulted highlands. Latitude range 0 to 30 degrees, longitude range -90 to -45 degrees.

  19. Unexpected fireworks! Active region 808

    NASA Astrophysics Data System (ADS)

    Roberts, Harry

    2005-12-01

    The activity in 2005 September of the large sunspot group 10808 is discussed. This was the return of active region 10798 of the previous month. That such activity on the Sun continued despite the proximity of Solar Minimum adds to the excitement and interest of these regions. Observations in hydrogen alpha light enable detailed phenomenon to be followed both on and off the Sun's disc.

  20. Revisiting Health Regionalization in Canada.

    PubMed

    Barker, Paul; Church, John

    2017-04-01

    Twenty years ago, many of Canada's provinces began to introduce regional health authorities to address problems with their health care systems. With this action, the provinces sought to achieve advances in community decision-making, the integration of health services, and the provision of care in the home and community. The authorities were also to help restrict health care costs. An assessment of the authorities indicates, however, that over the past two decades they have been unable to meet their objectives. Community representatives continue to play little role in determining the appropriate health services for their regions. Gains have been made towards integrating health services, but the plan for a near seamless set of health services has not been realized. Funding for health services remains focused on hospital and physician care, and health care expenditures have until very recently been little affected by regional authorities. This disappointing performance has caused some provinces to abandon their regional authorities, but this article argues that the provision of greater autonomy and a better public appreciation of their role and potential may lead to more successful regional authorities. Accordingly, the objective of this article is to reveal the shortcomings of regional health authorities in Canada while at the same time arguing that changes can be made to increase the chances of more workable authorities.

  1. Probing Metallicity across the Milky Way Disk with the VLA

    NASA Astrophysics Data System (ADS)

    Barnes, Jonathan; Balser, Dana S.; Wenger, Trey

    2016-01-01

    HII regions are sites of recent star formation where massive stars have ionized the surrounding gas. They are bright at radio wavelengths and can be detected throughout the Galactic disk. The Green Bank Telescope (GBT) HII Region Discovery Survey (HRDS) doubled the number of known HII regions in the first Galactic quadrant using radio recombination line (RRL) and free-free radio continuum emission at 8-10 GHz. The physical (electron) temperature, a proxy for metallicity, is derived from the line-to-continuum ratio. The metallicity is the abundance of metals, elements heavier than helium, and their distribution in the Milky Way provides information about Galactic evolution. These metallicities correspond to present day values because HII regions are relatively young (< 10 Myr). Here we discuss Very Large Array (VLA) RRL and continuum observations of 21, distant HRDS HII regions. The VLA provides a more sensitive and accurate measure of the radio continuum and therefore better determination of the metallicity. The data were reduced both manually and via a pipeline using CASA. We compare our results with our GBT data in preparation for a larger VLA HII region survey.

  2. Regional sinkhole susceptibility maps: The Latium Region case (central Italy)

    NASA Astrophysics Data System (ADS)

    La Vigna, F.; Teoli, P.; Mazza, R.; Leoni, G.; Capelli, G.

    2012-04-01

    Several and frequent studies were internationally presented about landslide susceptibility, meanwhile in literature is missing a broad diffusion of studies regarding sinkhole susceptibility. That's why sinkhole recurrence depends on several geological conditions related to specific geological and hydrogeological context (sinkhole prone area) that vary case by case. Notwithstanding this regionalization problem of sinkhole recurrence, in the central Appenine sedimentary basins (Italy) a certain number of geological, geomorphologic and hydrogeological conditions (sinkhole predisposing issues) can be considered in common between the surveyed sinkholes. Eventually this could be compared with similar geological conditions and sinkhole occurrence in the rest of Italy or in other countries. In this case study is presented a probabilistic approach regarding the Latium Region deriving from the comparison between the regional sinkhole inventory realized during a precedent project and the dataset of the new Hydrogeological Map of Latium Region (scale 1:100.000). Indexed elements, chosen because associated to the majority of sinkhole phenomena, are: outcropping lithologies, water table depth, main faults (even if buried), hydrothermal springs, land use and the epicentres of recent earthquakes. These indexed elements were weighted and combined in a matrix which preliminary result is the sinkhole susceptibility map of Latium Region. When definitively validated, this approach could be suitable for local authorities to planning more targeted studies in major hazard areas.

  3. Regional Variations in Diagnostic Practices

    PubMed Central

    Song, Yunjie; Skinner, Jonathan; Bynum, Julie; Sutherland, Jason; Wennberg, John E.; Fisher, Elliott S.

    2010-01-01

    BACKGROUND Current methods of risk adjustment rely on diagnoses recorded in clinical and administrative records. Differences among providers in diagnostic practices could lead to bias. METHODS We used Medicare claims data from 1999 through 2006 to measure trends in diagnostic practices for Medicare beneficiaries. Regions were grouped into five quintiles according to the intensity of hospital and physician services that beneficiaries in the region received. We compared trends with respect to diagnoses, laboratory testing, imaging, and the assignment of Hierarchical Condition Categories (HCCs) among beneficiaries who moved to regions with a higher or lower intensity of practice. RESULTS Beneficiaries within each quintile who moved during the study period to regions with a higher or lower intensity of practice had similar numbers of diagnoses and similar HCC risk scores (as derived from HCC coding algorithms) before their move. The number of diagnoses and the HCC measures increased as the cohort aged, but they increased to a greater extent among beneficiaries who moved to regions with a higher intensity of practice than among those who moved to regions with the same or lower intensity of practice. For example, among beneficiaries who lived initially in regions in the lowest quintile, there was a greater increase in the average number of diagnoses among those who moved to regions in a higher quintile than among those who moved to regions within the lowest quintile (increase of 100.8%; 95% confidence interval [CI], 89.6 to 112.1; vs. increase of 61.7%; 95% CI, 55.8 to 67.4). Moving to each higher quintile of intensity was associated with an additional 5.9% increase (95% CI, 5.2 to 6.7) in HCC scores, and results were similar with respect to laboratory testing and imaging. CONCLUSIONS Substantial differences in diagnostic practices that are unlikely to be related to patient characteristics are observed across U.S. regions. The use of clinical or claims-based diagnoses in

  4. Ig Constant Region Effects on Variable Region Structure and Function

    PubMed Central

    Janda, Alena; Bowen, Anthony; Greenspan, Neil S.; Casadevall, Arturo

    2016-01-01

    The adaptive humoral immune response is responsible for the generation of antimicrobial proteins known as immunoglobulin molecules or antibodies. Immunoglobulins provide a defense system against pathogenic microbes and toxins by targeting them for removal and/or destruction. Historically, antibodies have been thought to be composed of distinct structural domains known as the variable and constant regions that are responsible for antigen binding and mediating effector functions such as opsonization and complement activation, respectively. These domains were thought to be structurally and functionally independent. Recent work has revealed however, that in some families of antibodies, the two regions can influence each other. We will discuss the body of work that led to these observations, as well as the mechanisms that have been proposed to explain how these two different antibody regions may interact in the function of antigen binding. PMID:26870003

  5. Regional waveform calibration in the Pamir-Hindu Kush region

    NASA Astrophysics Data System (ADS)

    Zhu, Lupei; Helmberger, Donald V.; Saikia, Chandan K.; Woods, Bradley B.

    1997-10-01

    Twelve moderate-magnitude earthquakes (mb 4-5.5) in the Pamir-Hindu Kush region are investigated to determine their focal mechanisms and to relocate them using their regional waveform records at two broadband arrays, the Kyrgyzstan Regional Network (KNET), and the 1992 Pakistan Himalayas seismic experiment array (PAKH) in northern Pakistan. We use the "cut-and-paste" source estimation technique to invert the whole broadband waveforms for mechanisms and depths, assuming a one-dimensional velocity model developed for the adjacent Tibetan plateau. For several large events the source mechanisms obtained agree with those available from the Harvard centroid moment tensor (CMT) solutions. An advantage of using regional broadband waveforms is that focal depths can be better constrained either from amplitude ratios of Pnl to surface waves for crustal events or from time separation between the direct P and the shear-coupled P wave (sPn + sPmP) for mantle events. All the crustal events are relocated at shallower depths compared with their International Seismological Centre bulletin or Harvard CMT depths. After the focal depths are established, the events are then relocated horizontally using their first-arrival times. Only minor offsets in epicentral location are found for all mantle events and the bigger crustal events, while rather large offsets (up to 30 km) occur for the smaller crustal events. We also tested the performance of waveform inversion using only two broadband stations, one from the KNET array in the north of the region and one from the PAKH array in the south. We found that this geometry is adequate for determining focal depths and mechanisms of moderate size earthquakes in the Pamir-Hindu Kush region.

  6. Regional Transmission Projects: Finding Solutions

    SciTech Connect

    The Keystone Center

    2005-06-15

    The Keystone Center convened and facilitated a year-long Dialogue on "Regional Transmission Projects: Finding Solutions" to develop recommendations that will help address the difficult and contentious issues related to expansions of regional electric transmission systems that are needed for reliable and economic transmission of power within and across regions. This effort brought together a cross-section of affected stakeholders and thought leaders to address the problem with the collective wisdom of their experience and interests. Transmission owners sat at the table with consumer advocates and environmental organizations. Representatives from regional transmission organizations exchanged ideas with state and federal regulators. Generation developers explored common interests with public power suppliers. Together, the Dialogue participants developed consensus solutions about how to begin unraveling some of the more intractable issues surrounding identification of need, allocation of costs, and reaching consensus on siting issues that can frustrate the development of regional transmission infrastructure. The recommendations fall into three broad categories: 1. Recommendations on appropriate institutional arrangements and processes for achieving regional consensus on the need for new or expanded transmission infrastructure 2. Recommendations on the process for siting of transmission lines 3. Recommendations on the tools needed to support regional planning, cost allocation, and siting efforts. List of Dialogue participants: List of Dialogue Participants: American Electric Power American Transmission Company American Wind Energy Association California ISO Calpine Corporation Cinergy Edison Electric Institute Environmental Defense Federal Energy Regulatory Commission Great River Energy International Transmission Company ISO-New England Iowa Public Utility Board Kanner & Associates Midwest ISO National Association of Regulatory Utility Commissioners National Association

  7. Regional desertification: A global synthesis

    NASA Astrophysics Data System (ADS)

    Helldén, Ulf; Tottrup, Christian

    2008-12-01

    The paper presents results on the use of NOAA AVHRR data for desertification monitoring on a regional-global level. It is based on processing of the GIMMS 8 km global NDVI data set. Time series of annually integrated and standardized annual NDVI anomalies were generated and compared with a corresponding rainfall data set (1981-2003). The regions studied include the Mediterranean basin, the Sahel from the Atlantic to the Red Sea, major parts of the drylands of Southern Africa, China-Mongolia and the drylands of South America, i.e. important parts of the desertification prone drylands of the world. It is concluded that the suggested methodology is a robust and reliable way to assess and monitor vegetation trends and related desertification on a regional-global scale. A strong general relationship between NDVI and rainfall over time is demonstrated for considerable parts of the drylands. The results of performed trend analysis cannot be used to verify any systematic generic land degradation/desertification trend at the regional-global level. On the contrary, a "greening-up" seems to be evident over large regions.

  8. [Nitrogen flow in Huizhou region].

    PubMed

    Ma, Xiaobo; Wang, Zhaoyin; Koenig, Albert; Deng, Jiaquan

    2006-06-01

    Eutrophication is a serious problem of water body pollution. By the method of material flow accounting, this paper studied the human activities- related nitrogen flow in the system of environment and anthroposphere in Huizhou region. The non-point source pollution was quantified by export coefficient method, and the domestic discharge was estimated by demand-supply method. The statistic and dynamic analyses based on the investigation data of 1998 showed that the major nitrogen flows in this region were river loads, fertilizer and feedstuff imports, atmospheric deposition, animal excretes' degradation and volatilization, and the processes relating to burning and other emissions. In 1998, about 40% of nitrogen was detained in the system, which could be accumulated and yield potential environmental problems. The nitrogen export in this region was mainly by rivers, accounted for about 57%. A comparison of Huizhou region with the Danube and Changjiang basins showed that the unit area nitrogen exports in these three regions were of the same magnitude, and the per capita nitrogen exports were comparable.

  9. Does regional anaesthesia improve outcome?

    PubMed

    Hopkins, P M

    2015-12-01

    This review examines the recent evidence of an impact of regional anaesthesia on important clinical outcomes. Evidence was obtained from a variety of studies, with increasing numbers of analyses of large databases being prominent. The benefits and limitations of these approaches are considered in order to provide a context for interpretation of the data they generate. There should be little argument that correctly performed and appropriately used regional anaesthetic techniques can provide the most effective postoperative analgesia for the duration of the block, but the majority of studies suggest that this does not translate into improved longer-term surgical outcomes. The evidence for reduced incidence of major complications when regional anaesthesia is compared with, or added to, general anaesthesia is mixed. There appears to be a small effect in reducing blood loss during major joint arthroplasty. Some, but not all, studies demonstrate a reduced incidence of respiratory and infective complications with regional anaesthesia, but the effect on cardiovascular complications is variable. There are even some data consistent with a hypothesis that general anaesthesia may be protective against postoperative cognitive dysfunction. In conclusion, there is probably no generally applicable benefit in long-term outcomes with regional anaesthesia. More likely is an interaction between patient factors, the surgical procedure, and the relative capability of the anaesthetist to manage different types of anaesthesia. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Extending Regional Seismic Travel Time (RSTT) Tomography to New Regions

    DTIC Science & Technology

    2011-09-01

    Seism . Soc. Am. 59, 1365–1398. Flanagan, M. P., D. A. Dodge, and S. C. Myers (2008). GT merge process: Version 2.0, LLNL technical report, LLNL-TR...Validation of regional and teleseismic travel-time models by relocating ground-truth events, Bull. Seism . Soc. Amer. 94: 897–919. Zhao, L.-S. (1993

  11. Regional climate services: A regional partnership between NOAA and USDA

    USDA-ARS?s Scientific Manuscript database

    Climate services in the Midwest and Northern Plains regions have been enhanced by a recent addition of the USDA Climate Hubs to NOAA’s existing network of partners. This new partnership stems from the intrinsic variability of intra and inter-annual climatic conditions, which makes decision-making fo...

  12. Correlation of regional breath sound with regional ventilation in emphysema

    SciTech Connect

    Ploysongsang, Y.; Pare, J.A.; Macklem, P.T.

    1982-09-01

    We measured regional breath sound intensities (Ib) by a microphone amplifier system in 8 subjects with emphysema. We also measured regional white noise transmissions (Tn) from the same areas in all subjects. The recorded areas were 5, 10, 15, and 20 cm from the apex of the lung just lateral to the right anterior midclavicular line. Xenon ventilation indexes (xenon tidal raw counts, an index of total regional ventilation; xenon equilibration raw counts, an index of ventilating lung volume; xenon ventilation per unit volume (Vr), an index of ventilation per unit volume) were also recorded from the same areas. The Ib, Tn, Ib/Tn (an index of sound generation), and xenon ventilation indexes were all expressed as a fraction of the mean value of all four recorded areas. The Ib and Ib/Tn correlated best with the xenon tidal raw counts, correlated well with the xenon equilibration raw counts, and correlated poorly with Vr. We conclude that Ib and Ib/Tn can be used to quantify regional ventilation in subjects with emphysema.

  13. Northeast Regional Biomass Energy Program

    SciTech Connect

    O'Connell, R.A.

    1992-02-01

    The Northeast Regional Biomass Program (NRBP) is entering its ninth year of operation. The management and the objectives have virtually remained unchanged and are stated as follows. The program conducted by NRBP has three basic features: (1) a state grant component that provides funds (with a 50 percent matching requirement) to each of the states in the region to strengthen and integrate the work of state agencies involved in biomass energy; (2) a series of technical reports and studies in areas that have been identified as being of critical importance to the development of biomass energy in the region; and (3) a continuous long range planning component with heavy private sector involvement that helps to identify activities necessary to spur greater development and use of biomass energy in the Northeast.

  14. Regional Cooperation to Strengthen Safeguards

    SciTech Connect

    Minnini, Margot; Elkhamri, Oksana O.

    2016-06-06

    President Obama’s decision over four years ago to ”pivot” toward Asia represented an important strategic shift in American foreign policy and a rebalancing of U.S. economic and security engagement in the Asia-Pacific countries. The United States has since supported a variety of regional initiatives aimed at promoting nuclear security and safeguards. When a new regional organization, the Asia-Pacific Safeguards Network (APSN) was established in 2010, DOE/NNSA became an early member and enthusiastic advocate. Launched on the initiative of Australia, Japan, Republic of Korea, and Indonesia, the APSN aims to strengthen the quality and effectiveness of safeguards implementation in the Asia-Pacific region.

  15. Northeast Regional Biomass Energy Program

    SciTech Connect

    O'Connell, R.A.

    1992-04-01

    The Northeast Regional Biomass Program (NRBP) is entering its ninth year of operation. The management and the objectives have virtually remained unchanged and are stated as follows. The program conducted by NRBP has three basic features: (1) a state grant component that provides funds (with a 50 percent matching requirement) to each of the states in the region to strengthen and integrate the work of state agencies involved in biomass energy; (2) a series of technical reports and studies in areas that have been identified as being of critical importance to the development of biomass energy in the region; and (3) a continuous long range planning component with heavy private sector involvement that helps to identify activities necessary to spur greater development and use of biomass energy in the Northeast.

  16. Satellites monitor Atlanta regional development

    USGS Publications Warehouse

    Todd, William J.; Blackmon, C.C.; Rudasill, R.G.

    1979-01-01

    Since the adoption of a Regional Development Plan in 1975, the Atlanta Regional Commission has investigated methods for monitoring regional development patterns in a periodic, efficient manner. A promising approach appears to be the use of Landsat satellite data. In cooperation with the Earth Resources Observation Systems (EROS) Data Center, the commission used machine processing of digital temporal overlays of Landsat data collected in 1972, 1974 and 1976 to detect land use and land cover changes in the Atlanta metropolitan area. Results of the analysis revealed the conversion of forested and open space areas to residential, commercial and industrial land use in the urban-rural fringe zone from 1972 to 1974 and from 1974 to 1976. The study indicated that a land use and land cover change-detection program may be used to revise small-area forecasts of land use, population and employment made by planning models.

  17. Regional sea level change in the Thailand-Indonesia region

    NASA Astrophysics Data System (ADS)

    Fenoglio-Marc, L.; Becker, M. H.; Buchhaupt, C.

    2013-12-01

    It is expected that the regional sea level rise will strongly affect particular regions with direct impacts including submergence of coastal zones, rising water tables and salt intrusion into groundwaters. It can possibly also exacerbate other factors as floodings, associated to storms and hurricanes, as well as ground subsidence of anthropogenic nature. The Thailand-Vietnam-Indonesian region is one of those zones. On land, the Chao-Praya and Mekong Delta are fertile alluvial zones. The potential for sea level increases and extreme floodings due to global warming makes the Deltas a place where local, regional, and global environmental changes are converging. We investigate the relative roles of regional and global mechanisms resulting in multidecadal variations and inflections in the rate of sea level change. Altimetry and GRACE data are used to investigate the variation of land floodings. The land surface water extent is evaluated at 25 km sampling intervals over fifteen years (1993-2007) using a multisatellite methodology which captures the extent of episodic and seasonal inundations, wetlands, rivers, lakes, and irrigated agriculture, using passive and active (microwaves and visible observations. The regional sea level change is analysed during the period 1993-2012 using satellite altimetry, wind and ocean model data, tide gauge data and GPS. The rates of absolute eustatic sea level rise derived from satellite altimetry through 19-year long precise altimeter observations are in average higher than the global mean rate. Several tide gauge records indicate an even higher sea level rise relative to land. We show that the sea level change is closely linked to the ENSO mode of variability and strongly affected by changes in wind forcing and ocean circulation. We have determined the vertical crustal motion at a given tide gauge location by differencing the tide gauge sea level time-series with an equivalent time-series derived from satellite altimetry and by computing

  18. Automatic thoracic body region localization

    NASA Astrophysics Data System (ADS)

    Bai, PeiRui; Udupa, Jayaram K.; Tong, YuBing; Xie, ShiPeng; Torigian, Drew A.

    2017-03-01

    Radiological imaging and image interpretation for clinical decision making are mostly specific to each body region such as head & neck, thorax, abdomen, pelvis, and extremities. For automating image analysis and consistency of results, standardizing definitions of body regions and the various anatomic objects, tissue regions, and zones in them becomes essential. Assuming that a standardized definition of body regions is available, a fundamental early step needed in automated image and object analytics is to automatically trim the given image stack into image volumes exactly satisfying the body region definition. This paper presents a solution to this problem based on the concept of virtual landmarks and evaluates it on whole-body positron emission tomography/computed tomography (PET/CT) scans. The method first selects a (set of) reference object(s), segments it (them) roughly, and identifies virtual landmarks for the object(s). The geometric relationship between these landmarks and the boundary locations of body regions in the craniocaudal direction is then learned through a neural network regressor, and the locations are predicted. Based on low-dose unenhanced CT images of 180 near whole-body PET/CT scans (which includes 34 whole-body PET/CT scans), the mean localization error for the boundaries of superior of thorax (TS) and inferior of thorax (TI), expressed as number of slices (slice spacing ≍ 4mm)), and using either the skeleton or the pleural spaces as reference objects, is found to be 3,2 (using skeleton) and 3, 5 (using pleural spaces) respectively, or in mm 13, 10 mm (using skeleton) and 10.5, 20 mm (using pleural spaces), respectively. Improvements of this performance via optimal selection of objects and virtual landmarks and other object analytics applications are currently being pursued. and the skeleton and pleural spaces used as a reference objects

  19. Solitary neurilemmoma in postaural region.

    PubMed

    Adhikary, Bivas; Sen, Indranil; Basu, Asim Jiban; Bandyopadhyay, Saumyendra Nath; Saha, Debdas; Basu, Sumit Kumar

    2007-05-01

    Neurilemmoma in postaural region arising from great auricular nerve is an extremely rare tumour. An 11 years boy presented with pain and swelling behind his left ear for last 3-4 years. The clinical examination revealed the swelling appeared to be diffuse with the margin being ill defined. On radiological examination a diffuse homogeneous mass was seen in the postaural region of the left side. The tumour was completely removed by an incision through postaural route. Histopathological study revealed neurilemmoma. Postoperative period was uneventful.

  20. Hydrodynamics of post CHF region

    SciTech Connect

    Ishii, M.; De Jarlais, G.

    1984-04-01

    Among various two-phase flow regimes, the inverted flow in the post-dryout region is relatively less well understood due to its special heat transfer conditions. The review of existing data indicates further research is needed in the areas of basic hydrodynamics related to liquid core disintegration mechanisms, slug and droplet formations, entrainment, and droplet size distributions. In view of this, the inverted flow is studied in detail both analytically and experimentally. Criteria for initial flow regimes in the post-dryout region are given. Preliminary models for subsequent flow regime transition criteria are derived together with correlations for a mean droplet diameter based on the adiabatic simulation data.

  1. Floristic study of Mirabad region.

    PubMed

    Hasanzadeh Gorttapeh, A; Panahy, J

    2007-10-15

    The study area (Mirabad) is located between 36 degrees, 55' to 37 degrees north latitude and 45 degrees, 05' to 55 degrees, 44' east longitude in west Azerbaijan province. In this study, Flora of this region was determined by using available references. We encountered 192 species that belongs to 126 genera and 41 families. The largest family of region is Asteraceae with 31 sp. and the largest Genera is Astragalus with 7 sp. The main life forms are: Hemicryptophyte with 30.2% and Therophyte with 28.1%. The most extended chorotype with 62.5% is related to: Irano_Turanian.

  2. Regional High School Senior Survey.

    ERIC Educational Resources Information Center

    Day, Philip R., Jr.

    In order to identify the educational needs and aspirations of graduating high school seniors in the service region of the University of Maine at Augusta, a survey instrument was designed and administered to 1,950 seniors at 19 institutions. In all, 1,744 completed surveys were returned, a 92 percent response rate. The data are sub-grouped into…

  3. Biocapacity optimization in regional planning

    PubMed Central

    Guo, Jianjun; Yue, Dongxia; Li, Kai; Hui, Cang

    2017-01-01

    Ecological overshoot has been accelerating across the globe. Optimizing biocapacity has become a key to resolve the overshoot of ecological demand in regional sustainable development. However, most literature has focused on reducing ecological footprint but ignores the potential of spatial optimization of biocapacity through regional planning of land use. Here we develop a spatial probability model and present four scenarios for optimizing biocapacity of a river basin in Northwest China. The potential of enhanced biocapacity and its effects on ecological overshoot and water consumption in the region were explored. Two scenarios with no restrictions on croplands and water use reduced the overshoot by 29 to 53%, and another two scenarios which do not allow croplands and water use to increase worsened the overshoot by 11 to 15%. More spatially flexible transition rules of land use led to higher magnitude of change after optimization. However, biocapacity optimization required a large amount of additional water resources, casting considerable pressure on the already water-scarce socio-ecological system. Our results highlight the potential for policy makers to manage/optimize regional land use which addresses ecological overshoot. Investigation on the feasibility of such spatial optimization complies with the forward-looking policies for sustainable development and deserves further attention. PMID:28112224

  4. Regional Highlights of Climate Change

    Treesearch

    David L. Peterson; J.M. Wolken; Teresa Hollingsworth; Christian Giardina; J.S. Littell; Linda Joyce; Chris Swanston; Stephen Handler; Lindsey Rustad; Steve McNulty

    2014-01-01

    Climatic extremes, ecological disturbance, and their interactions are expected to have major effects on ecosystems and social systems in most regions of the United States in the coming decades. In Alaska, where the largest temperature increases have occurred, permafrost is melting, carbon is being released, and fire regimes are changing, leading to a...

  5. MC-1 Mare Boreum Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-1 quadrangle, Mare Boreum region of Mars. The central part is covered by a residual ice cap that is cut by spiral-patterned troughs exposing layered terrain. The cap is surrounded by broad flat plains and large dune fields. Latitude range 65 to 90, longitude range -180 to 180.

  6. MC-5 Ismenius Lacus Region

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mars digital-image mosaic merged with color of the MC-5 quadrangle, Ismenius Lacus region of Mars. Heavily cratered highlands of the southern part are separated from the relatively smooth plains of the northern part by a belt of dissected terrain, containing mesas and buttes. Latitude range 30 to 65 degrees, longitude range -60 to 0 degrees.

  7. Jupiter Great Red Spot Region

    NASA Image and Video Library

    1996-09-26

    This mosaic of Jupiter Great Red Spot taken by NASA Voyager 1, shows the area around the northern boundary where a white cloud is seen which extends to east of the region. http://photojournal.jpl.nasa.gov/catalog/PIA00065

  8. Multimodal analgesia and regional anaesthesia.

    PubMed

    Tornero Tornero, C; Fernández Rodríguez, L E; Orduña Valls, J

    Multimodal analgesia provides quality analgesia, with fewer side effects due to the use of combined analgesics or analgesic techniques. Regional anaesthesia plays a fundamental role in achieving this goal. The different techniques of regional anaesthesia that include both peripheral and central blocks in either a single dose or in continuous infusion help to modulate the nociceptive stimuli that access the central level. The emergence of the ultrasound as an effective system to perform regional anaesthesia techniques has allowed the development of new regional anaesthesia techniques that formerly could not be carried out since only neurostimulation or skin references were used. It is essential to take into account that even with effective blocking it is advisable to associate other drugs by other routes, in this way we will be able to reduce the required doses individually and attempt to achieve a synergistic, not purely additive, effect. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. PREL Pacific Region Language Cards.

    ERIC Educational Resources Information Center

    Pacific Region Educational Lab., Honolulu, HI.

    This collection of 10 cue cards presents English translations of common English words and expressions into 10 Pacific Region languages: Palauan, Samoan, Chamorro, Hawaiian, Carolinian, Chuukese, Pohnpeian, Marshallese, Yapese, and Kosraean. The cards translate the following: hello, good morning, good afternoon, good night, thank you, you're…

  10. Biocapacity optimization in regional planning

    NASA Astrophysics Data System (ADS)

    Guo, Jianjun; Yue, Dongxia; Li, Kai; Hui, Cang

    2017-01-01

    Ecological overshoot has been accelerating across the globe. Optimizing biocapacity has become a key to resolve the overshoot of ecological demand in regional sustainable development. However, most literature has focused on reducing ecological footprint but ignores the potential of spatial optimization of biocapacity through regional planning of land use. Here we develop a spatial probability model and present four scenarios for optimizing biocapacity of a river basin in Northwest China. The potential of enhanced biocapacity and its effects on ecological overshoot and water consumption in the region were explored. Two scenarios with no restrictions on croplands and water use reduced the overshoot by 29 to 53%, and another two scenarios which do not allow croplands and water use to increase worsened the overshoot by 11 to 15%. More spatially flexible transition rules of land use led to higher magnitude of change after optimization. However, biocapacity optimization required a large amount of additional water resources, casting considerable pressure on the already water-scarce socio-ecological system. Our results highlight the potential for policy makers to manage/optimize regional land use which addresses ecological overshoot. Investigation on the feasibility of such spatial optimization complies with the forward-looking policies for sustainable development and deserves further attention.

  11. Regional Libraries Study, FY93.

    ERIC Educational Resources Information Center

    Vermont State Dept. of Libraries, Montpelier.

    The Vermont General Assembly mandated an evaluation of the regional library program of the Vermont State Department of Libraries. To carry out this charge, the department initiated a 14-month review of the program with three components: an internal review of library service, use, and costs; public library input derived from a detailed survey and…

  12. Regional Background Fine Particulate Matter

    EPA Science Inventory

    A modeling system composed of the global model GEOS-Chem providing hourly lateral boundary conditions to the regional model CMAQ was used to calculate the policy relevant background level of fine particulate: matter. Simulations were performed for the full year of 2004 over the d...

  13. SDO Sees Active Region Outbursts

    NASA Image and Video Library

    This close up video by NASA’s Solar Dynamics Observatory shows an active region near the right-hand edge of the sun’s disk, which erupted with at least a dozen minor events over a 30-hour period fr...

  14. Future and present regional wind

    NASA Astrophysics Data System (ADS)

    Salameh, T.; Vrac, M.; Drobinski, P.; Naveau, P.

    2009-04-01

    Accurate and rapid determination of near-surface wind fields in a complex area (orography, inhomogeneous surface properties) is a challenge for applications like the evaluation of wind energy production, the prediction of pollution transport and hazardous conditions for aeronautics and ship navigation, among others. This work presents a statistical downscaling approach for regional near-surface wind field in the region of southern France (characterized by the presence of major mountain ranges). It is based on generalized additive models (GAM, Salameh et al. 2008), relating large-scale upper air to local-scale surface atmospheric fields. We apply our statistical downscaling model conditionally on regional circulation patterns defined from measurements. Hence, near-surface wind components in southern France are simulated based on large-scale information from ERA-40 reanalyses (1991-2001) and from IPCC scenarios (1991-2001 and 2040-2050). The performances of our method are evaluated, (1) by comparing downscaled wind from ERA-40 and from IPCC, and (2) by comparing them with measurements, for the period 1991-2001. Then, we evaluate the change in regional atmospheric circulations in southern France, by comparing future and present downscaled wind.

  15. Microinstabilities in the pedestal region

    NASA Astrophysics Data System (ADS)

    Dickinson, David; Dudson, Benjamin; Wilson, Howard; Roach, Colin

    2014-10-01

    The regulation of transport at the pedestal top is important for the inter-ELM pedestal dynamics. Linear gyrokinetic analysis of the pedestal region during an ELM cycle on MAST has shown kinetic ballooning modes to be unstable at the knee of the pressure profile and in the steep pedestal region whilst microtearing modes (MTMs) dominate in the shallow gradient region inboard of the pedestal top. The transition between these instabilities at the pedestal knee has been observed in low and high collisionality MAST pedestals, and is likely to play an important role in the broadening of the pedestal. Nonlinear simulations are needed in this region to understand the microturbulence, the corresponding transport fluxes, and to gain further insight into the processes underlying the pedestal evolution. Such gyrokinetic simulations are numerically challenging and recent upgrades to the GS2 gyrokinetic code help improve their feasibility. We are also exploring reduced models that capture the relevant physics using the plasma simulation framework BOUT + + . An electromagnetic gyrofluid model has recently been implemented with BOUT + + that has significantly reduced computational cost compared to the gyrokinetic simulations against which it will be benchmarked. This work was funded by the RCUK Energy programme, EURATOM and a EUROFusion fellowship WP14-FRF-CCFE/Dickinson and was carried out using: HELIOS at IFERC, Japan; ARCHER (EPSRC Grant No. EP/L000237/1); HECToR (EPSRC Grant No. EP/H002081/1).

  16. Biocapacity optimization in regional planning.

    PubMed

    Guo, Jianjun; Yue, Dongxia; Li, Kai; Hui, Cang

    2017-01-23

    Ecological overshoot has been accelerating across the globe. Optimizing biocapacity has become a key to resolve the overshoot of ecological demand in regional sustainable development. However, most literature has focused on reducing ecological footprint but ignores the potential of spatial optimization of biocapacity through regional planning of land use. Here we develop a spatial probability model and present four scenarios for optimizing biocapacity of a river basin in Northwest China. The potential of enhanced biocapacity and its effects on ecological overshoot and water consumption in the region were explored. Two scenarios with no restrictions on croplands and water use reduced the overshoot by 29 to 53%, and another two scenarios which do not allow croplands and water use to increase worsened the overshoot by 11 to 15%. More spatially flexible transition rules of land use led to higher magnitude of change after optimization. However, biocapacity optimization required a large amount of additional water resources, casting considerable pressure on the already water-scarce socio-ecological system. Our results highlight the potential for policy makers to manage/optimize regional land use which addresses ecological overshoot. Investigation on the feasibility of such spatial optimization complies with the forward-looking policies for sustainable development and deserves further attention.

  17. PREL Pacific Region Language Cards.

    ERIC Educational Resources Information Center

    Pacific Region Educational Lab., Honolulu, HI.

    This collection of 10 cue cards presents English translations of common English words and expressions into 10 Pacific Region languages: Palauan, Samoan, Chamorro, Hawaiian, Carolinian, Chuukese, Pohnpeian, Marshallese, Yapese, and Kosraean. The cards translate the following: hello, good morning, good afternoon, good night, thank you, you're…

  18. Education and Italian Regional Development

    ERIC Educational Resources Information Center

    Di Liberto, Adriana

    2008-01-01

    In this paper, we study the connection between growth and human capital in a convergence regression for the panel of Italian regions. We include measures of average primary, secondary and tertiary education. We find that increased education seems to contribute to growth only in the South. Decomposing total schooling into its three constituent…

  19. Higher Education and European Regionalism.

    ERIC Educational Resources Information Center

    Paterson, Lindsay

    2001-01-01

    Speculates about the relationship between two fundamental social changes occurring in Europe: the development of a mass higher education system and the slow decay of the old states that were inherited from the 19th century, eroded from below by various movements for national and regional autonomy, and eroded from above by the growing power and…

  20. Regional Needs Analysis Report. 2011

    ERIC Educational Resources Information Center

    Washington Higher Education Coordinating Board, 2011

    2011-01-01

    The Higher Education Coordinating Board (HECB) is required to develop a comprehensive and ongoing needs assessment process to analyze demand for additional degrees and programs [RCW 28B.76.230 (1)]. This report fulfills a portion of that mandate by focusing on employer demand on the regional level, but also includes additional information on…