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Sample records for bipolar proto-planetary nebula

  1. Proto-planetary nebulae

    International Nuclear Information System (INIS)

    Zuckerman, B.

    1978-01-01

    A 'proto-planetary nebula' or a 'planetary nebula progenitor' is the term used to describe those objects that are losing mass at a rate >approximately 10 -5 Msolar masses/year (i.e. comparable to mass loss rates in planetary nebulae with ionized masses >approximately 0.2 Msolar masses) and which, it is believed, will become planetary nebulae themselves within 5 years. It is shown that most proto-planetary nebulae appear as very red objects although a few have been 'caught' near the middle of the Hertzsprung-Russell diagram. The precursors of these proto-planetaries are the general red giant population, more specifically probably Mira and semi-regular variables. (Auth.)end

  2. Proto-planetary nebulae. I. The extreme bipolar nebulae M2-9 and M1-91

    International Nuclear Information System (INIS)

    Goodrich, R.W.

    1991-01-01

    Results are presented on a long-slit optical spectroscopy measurements of the prototype bipolar planetary nebula M2-9 and the M1-91 bipolar nebula, performed in order to determine the nature of the morphology of the wings of these two nebulae. It is concluded that the overall bipolar morphologies of these nebulae might be due to the orbital motions of binaries, with the orbital angular momentum vector defining the axis of the nebula. Secondary symmetries in the nebulae, such as the point-symmetric knots in M1-91, could be due to other symmetries, such as the rotation axis of one of the individual stars or the polar axis of the accretion disk. 39 refs

  3. ISO Spectroscopy of Proto-Planetary Nebulae

    Science.gov (United States)

    Hrivnak, Bruce J.

    2000-01-01

    The goal of this program was to determine the chemical properties of the dust shells around protoplanetary nebulae (PPNs) through a study of their short-wavelength (6-45 micron) infrared spectra. PPNs are evolved stars in transition from the asymptotic giant branch to the planetary nebula stages. Spectral features in the 10 to 20 gm region indicate the chemical nature (oxygen- or carbon-rich), and the strengths of the features relate to the physical properties of the shells. A few bright carbon-rich PPNs have been observed to show PAH features and an unidentified 21 micron emission feature. We used the Infrared Space Observatory (ISO) to observe a sample of IRAS sources that have the expected properties of PPNs and for which we have accurate positions. Some of these have optical counterparts (proposal SWSPPN01) and some do not (SWSPPN02). We had previously observed these from the ground with near-infrared photometry and, for those with visible counterparts, visible photometry and spectroscopy, which we have combined with these new ISO data in the interpretation of the spectra. We have completed a study of the unidentified emission feature at 21 micron in eight sources. We find the shape of the feature to be the same in all of the sources, with no evidence of any substructure. The ratio of the emission peak to continuum ranges from 0.13 to 1.30. We have completed a study of seven PPNs and two other carbon-rich objects for which we had obtained ISO 2-45 micron observations. The unidentified emission features at 21 and 30 micron were detected in six sources, including four new detections of the 30 micron feature. This previously unresolved 30 micron feature was resolved and found to consist of a broad feature peaking at 27.2 micron (the "30 micron" feature) and a narrower feature peaking at 25.5 micron (the "26 micron" feature). This new 26 micron feature is detected in eight sources and is particularly strong in IRAS Z02229+6208 and 16594-4656. The unidentified

  4. Classification of ISO SWS 01 spectra of proto-planetary nebulae: a search for precursors of planetary nebulae with [WR] central stars

    OpenAIRE

    Szczerba, R.; Stasi{ń}ska, G.; Siódmiak, N.; Górny, S. K.

    2002-01-01

    We have analyzed ISO SWS 01 observations for 61 proto-planetary nebulae candidates and classified their spectra according to their dominant chemistry. On the basis of our classification and the more general classification of SWS 01 spectra by Kraemer et al. (2002) we discuss the connection between proto-planetary nebulae candidates and planetary nebulae, with emphasis on possible precursors of planetary nebulae with [WR] central stars.

  5. He 2-104 - A symbiotic proto-planetary nebula?

    International Nuclear Information System (INIS)

    Schwarz, H.E.; Aspin, C.; Lutz, J.H.

    1989-01-01

    CCD observations are presented for He 2-104, an object previously classified as both PN and symbiotic star, which show that this is in fact a protoplanetary nebula (PPN) with a dynamical age of about 800 yr. The presence of highly collimated jets, extending over 75 arcsec on the sky, combined with an energy distribution showing a hot as well as a cool component, indicates that He 2-104 is a binary PPN. Since the primary is probably a Mira with a 400-d period (as reported by Whitelock, 1988), it is proposed that the system is a symbiotic PPN. 16 refs

  6. The offset dependent behavior of narrow optical emission features in the Red Rectangle proto-planetary nebula

    NARCIS (Netherlands)

    Wehres, N.; Linnartz, H.; Van Winckel, H.; Tielens, A. G. G. M.

    Context. The Red Rectangle proto-planetary nebula provides a unique laboratory to study the physical conditions and chemical processes in stellar outflows. Snapshots of the ongoing chemical evolution are obtained by monitoring spectra as function of the offset from the central star. Aims. The focus

  7. Where are the Binaries? Results of a Long-term Search for Radial Velocity Binaries in Proto-planetary Nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Hrivnak, Bruce J.; Lu, Wenxian [Department of Physics and Astronomy, Valparaiso University, Valparaiso, IN 46383 (United States); Steene, Griet Van de [Royal Observatory of Belgium, Astronomy and Astrophysics, Ringlaan 3, Brussels (Belgium); Winckel, Hans Van [Instituut voor Sterrenkunde, K.U. Leuven University, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Sperauskas, Julius [Vilnius University Observatory, Ciurlionio 29 Vilnius 2009 (Lithuania); Bohlender, David, E-mail: bruce.hrivnak@valpo.edu, E-mail: wen.lu@valpo.edu, E-mail: g.vandesteene@oma.be, E-mail: Hans.VanWinckel@ster.kuleuven.be, E-mail: julius.sperauskas@ff.vu.lt, E-mail: David.Bohlender@nrc-cnrc.gc.ca [National Research Council of Canada, Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada)

    2017-09-10

    We present the results of an expanded, long-term radial velocity search (25 years) for evidence of binarity in a sample of seven bright proto-planetary nebulae (PPNe). The goal is to investigate the widely held view that the bipolar or point-symmetric shapes of planetary nebulae (PNe) and PPNe are due to binary interactions. Observations from three observatories were combined from 2007 to 2015 to search for variations on the order of a few years and then combined with earlier observations from 1991 to 1995 to search for variations on the order of decades. All seven show velocity variations due to periodic pulsation in the range of 35–135 days. However, in only one PPN, IRAS 22272+5435, did we find even marginal evidence for multi-year variations that might be due to a binary companion. This object shows marginally significant evidence of a two-year period of low semi-amplitude, which could be due to a low-mass companion, and it also displays some evidence of a much longer period of >30 years. The absence of evidence in the other six objects for long-period radial velocity variations due to a binary companion sets significant constraints on the properties of any undetected binary companions: they must be of low mass, ≤0.2 M {sub ⊙}, or long period, >30 years. Thus the present observations do not provide direct support for the binary hypothesis to explain the shapes of PNe and PPNe and severely constrains the properties of any such undetected companions.

  8. Roberts 22: a bipolar nebula with OH emission

    International Nuclear Information System (INIS)

    Allen, D.A.; Hyland, A.R.; Caswell, J.L.

    1980-01-01

    Roberts 22 is a bipolar reflection nebula illuminated by a hidden A2 Ie star. Most of its energy is radiated at infrared wavelengths. It also shows strong OH maser emission (OH 284.18 - 0.79) on the 1612 and 1665 MHz transitions, generally similar to the masers associated with M stars having infrared excesses. But the system contains no late-type star. This remarkable assemblage of attributes makes Roberts 22 unique; however, it is probably a key member of the newly-recognized population of bipolar nebulae. From an analysis of the properties of Roberts 22 some published interpretations of other bipolar nebulae are questioned, in particular the derivation of spectral types for their underlying stars by the assumption of photo-ionization of the gas, and their evolutionary description as proto-planetary nebulae. (author)

  9. A Study of the 3.3 and 3.4 μm Emission Features in Proto-Planetary Nebulae

    Science.gov (United States)

    Hrivnak, Bruce J.; Geballe, T. R.; Kwok, Sun

    2007-06-01

    Medium-resolution spectra have been obtained of seven carbon-rich proto-planetary nebulae (PPNs) and one young planetary nebula from 3.2 to 3.8 μm, an interval containing the prominent hydrocarbon CH stretches at 3.3 and 3.4 μm due to aromatic and aliphatic structures, respectively. The 3.3 μm feature is newly identified in IRAS 23304+6147, 22223+4327, and 06530-0213 and is confirmed in Z02229+6208. Three of the PPNs emit in the 3.4 μm feature, two of these being new identifications, IRAS 20000+3239 and 01005+7910, with two others showing possible detections. The 3.3 and 3.4 μm emission features in IRAS 22272+5435 are seen in the nebula offset from the star but not at the position of the central star, consistent with the 2003 results of Goto et al. A similar distribution is seen for the 3.3 μm feature in IRAS 22223+4327. All of the PPNs except IRAS 22272+5435 show Class A 3 μm emission features. These observations, when combined with those of the approximately equal number of other carbon-rich PPNs previously observed, demonstrate that there are large differences in the 3 μm emission bands, even for PPNs with central stars of similar spectral type, and thus that the behavior of the bands does not depend solely on spectral type. We also investigated other possible correlations to help explain these differences. These differences do not depend on the C/O value, since the Class B sources fall within the C/O range found for Class A. All of these 3.3 μm sources also show C2 absorption and 21 μm emission features, except IRAS 01005+7910, which is the hottest source at B0. This research is based on observations made at the W. M. Keck Observatory by Gemini staff, supported by the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., on behalf of the international Gemini partnership of Argentina, Australia, Brazil, Canada, Chile, the United Kingdom, and the United States of America. The W. M. Keck Observatory is

  10. Bipolar nebulae and type I planetary nebulae

    International Nuclear Information System (INIS)

    Calvet, N.; Peimbert, M.

    1983-01-01

    It is suggested that the bipolar nature of PN of type I can be explained in terms of their relatively massive progenitors (Msub(i) 2.4 Msub(o)), that had to lose an appreciable fraction of their mass and angular momentum during their planetary nebulae stage. The following objects are discussed in relation with this suggestion: NGC 6302, NGC 2346, NGC 2440, CRL 618, Mz-3 and M2-9. It is found that CRL 618 is overbundant in N/O by a factor of 5-10 relative to the Orion Nebula. (author)

  11. A SOFIA FORCAST Grism Study of the Mineralogy of Dust in the Winds of Proto-planetary Nebulae: RV Tauri Stars and SRd Variables

    Energy Technology Data Exchange (ETDEWEB)

    Arneson, R. A.; Gehrz, R. D.; Woodward, C. E.; Shenoy, D. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, 106 Pleasant Street S.E., Minneapolis, MN 55455 (United States); Helton, L. A. [USRA-SOFIA Science Center, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Evans, A. [Astrophysics Group, Lennard Jones Laboratory, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Keller, L. D. [Department of Physics and Astronomy, 264 Center for Natural Sciences, Ithaca College, Ithaca, NY 14850 (United States); Hinkle, K. H. [National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726 (United States); Jura, M. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Lebzelter, T. [Institute for Astrophysics (IfA), University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria); Lisse, C. M. [Solar System Exploration Branch, Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723 (United States); Rushton, M. T. [Astronomical Institute of the Romanian Academy, Str. Cutitul de Argint 5, Bucharest, 040557 (Romania); Mizrachi, J., E-mail: arneson@astro.umn.edu [Biomedical Engineering Department, Stony Brook University, Stony Brook, NY 11794 (United States)

    2017-07-01

    We present a SOFIA FORCAST grism spectroscopic survey to examine the mineralogy of the circumstellar dust in a sample of post-asymptotic giant branch (post-AGB) yellow supergiants that are believed to be the precursors of planetary nebulae. Our mineralogical model of each star indicates the presence of both carbon-rich and oxygen-rich dust species—contrary to simple dredge-up models—with a majority of the dust in the form of amorphous carbon and graphite. The oxygen-rich dust is primarily in the form of amorphous silicates. The spectra do not exhibit any prominent crystalline silicate emission features. For most of the systems, our analysis suggests that the grains are relatively large and have undergone significant processing, supporting the hypothesis that the dust is confined to a Keplerian disk and that we are viewing the heavily processed, central regions of the disk from a nearly face-on orientation. These results help to determine the physical properties of the post-AGB circumstellar environment and to constrain models of post-AGB mass loss and planetary nebula formation.

  12. The Boomerang Nebula: a highly polarized bipolar

    International Nuclear Information System (INIS)

    Taylor, K.N.R.; Scarrott, S.M.

    1980-01-01

    An optical linear polarization map of a bipolar nebula is presented. Polarizations of approximately 60 per cent are observed in the optically thin lobes. The map leads to a geometry of the object consisting of a central star with an equatorial disc of dust and optically thin lobes illuminated by the central star. The grains in the disc are aligned. The object is a protoplanetary nebula. (author)

  13. A new bipolar nebula in Centaurus

    International Nuclear Information System (INIS)

    Wegner, G.; Glass, I.S.

    1979-01-01

    A new bipolar or butterfly-shaped nebula has been discovered and shown to have an infrared excess. The spectra of the central object and wings are of similar type, around G0. No emission lines are apparent. The infrared excess appears to be due to thermal emission from dust. (U.K.)

  14. The Toby Jug nebula (IC 2220): a bipolar and biconical nebula

    International Nuclear Information System (INIS)

    Perkins, H.G.; King, D.J.; Scarrott, S.M.

    1981-01-01

    An optical linear polarization map of IC 2220, the nebula surrounding the cool red giant HD 65750, is presented. The nebula appears to be bipolar and biconical in structure. The mass of the nebula is estimated to be 0.01 solar mass and is consistent with the nebula being formed from the current mass loss stage of the central star. (author)

  15. Models for the structure and origin of bipolar nebulae

    International Nuclear Information System (INIS)

    Morris, M.

    1981-01-01

    The appearance of bipolar nebulae-symmetric reflection nebulae centered on evolved, mass-losing stars-can most simply be accounted for in terms of an axisymmetric distribution of outflowing dust in which the dust is concentrated towards an equatorial plane and declines monotonically with latitude above that plane. The symmetrically placed ''horns'' that can be seen radiating out of some bipolar nebulae, notably GL 2688, are a natural consequence of such a dust distribution if, at some latitude, the radial optical depth to starlight falls rapidly below unity. Several models of bipolar nebulae are presented. These structural models for bipolar nebulae lead in turn to an investigation of how such a geometry might arise. Although nonradial pulsation, rotationally forced mass ejection by a single star, and mass loss from a common envelope binary are all considered, the most attractive origin for bipolar nebulae is a binary star system in which the primary is evolving up the red giant branch to the point at which its radius approaches its tidal radius. If this occurs before corotation of the primary with the secondary's orbit can be achieved, then matter from the primary's enveloped can be gravitationally ejected from the system by the secondary, the ejected material being concentrated toward the system's equatorial plane. Numerical models of this phenomenon show that gravitational ejection from an asynchronous binary system easily leads to terminal outflow velocities in the observed range (20--50 km s -1 ), and that the rate of mass loss and the time scale over which the mass ejection takes place are consistent with observations if the particle density in the outer layers of the primary's atmosphere from which the material is extracted is in the range 10 14 --10 15 cm -3 . If this hypothesis is applicable, bipolar nebulae will probably become planetary nebulae, as previously suggested on observational grounds

  16. Morphology of bipolar planetary nebulae. I. Two-dimensional spectrophotometry

    International Nuclear Information System (INIS)

    Pascoli, G.

    1990-01-01

    Two-dimensional spectrophotometric observations of bipolar planetary nebulae were performed by using a CCD detector mounted at the Cassegrain focus of either 1.54 m Danish Telescope or 2.2 m German Telescope at La Silla (ESO) in Chile. Emission lines have been selected with the help of narrow band-pass interference filters (Δλ∼ 10 - 20 A). Isophotal maps in various lines Hα, [NII] λ 6584, [OIII] λ 5007 and [SII] λλ 6717-6731 are presented. Particular attention has been given to scrutinize the symmetries inside a few bipolar planetary nebulae, in order to subsequently investigate their space structure

  17. Radiative Transfer Modeling in Proto-planetary Disks

    Science.gov (United States)

    Kasper, David; Jang-Condell, Hannah; Kloster, Dylan

    2016-01-01

    Young Stellar Objects (YSOs) are rich astronomical research environments. Planets form in circumstellar disks of gas and dust around YSOs. With ever increasing capabilities of the observational instruments designed to look at these proto-planetary disks, most notably GPI, SPHERE, and ALMA, more accurate interfaces must be made to connect modeling of the disks with observation. PaRTY (Parallel Radiative Transfer in YSOs) is a code developed previously to model the observable density and temperature structure of such a disk by self-consistently calculating the structure of the disk based on radiative transfer physics. We present upgrades we are implementing to the PaRTY code to improve its accuracy and flexibility. These upgrades include: creating a two-sided disk model, implementing a spherical coordinate system, and implementing wavelength-dependent opacities. These upgrades will address problems in the PaRTY code of infinite optical thickness, calculation under/over-resolution, and wavelength-independent photon penetration depths, respectively. The upgraded code will be used to better model disk perturbations resulting from planet formation.

  18. Spectrum and the structure of the bipolar nebula S 106

    Energy Technology Data Exchange (ETDEWEB)

    Solf, J [Max-Planck-Institut fuer Astronomie, Heidelberg (Germany, F.R.)

    1980-12-01

    Optically the compact region S 106 appears as a bipolar nebula with the exciting stellar source located between the lobes and embedded in a flat disk of material of high visual extinction. Associated with the nebula is a massive molecular cloud exhibiting a rotating disk-like structure, the axis of rotation being observed in the same direction as the bipolar axis of the nebula. We analyse new optical and near-infrared spectra obtained with an image-tube spectrograph. The emission line spectrum of both lobes resembles that of the Orion nebula and indicates high electron density throughout. The nebular continuum discovered in both lobes is interpreted as originating from an early-type stellar source between the lobes, and scattered by dust particles coexisting with the ionized gas within the lobes. The Hsub(..cap alpha..) radial velocity field indicates supersonic motion of ionized material flowing radially outward through the lobes. The shape and kinematic structure of the lobes are in qualitative agreement with the predictions of the champagne model of Tenorio-Tagle (1979) applied to the case of star formation near the center of a disk-shaped dense cloud.

  19. POST ASYMPTOTIC GIANT BRANCH BIPOLAR REFLECTION NEBULAE: RESULT OF DYNAMICAL EJECTION OR SELECTIVE ILLUMINATION?

    International Nuclear Information System (INIS)

    Koning, N.; Kwok, Sun; Steffen, W.

    2013-01-01

    A model for post asymptotic giant branch bipolar reflection nebulae has been constructed based on a pair of evacuated cavities in a spherical dust envelope. Many of the observed features of bipolar nebulae, including filled bipolar lobes, an equatorial torus, searchlight beams, and a bright central light source, can be reproduced. The effects on orientation and dust densities are studied and comparisons with some observed examples are offered. We suggest that many observed properties of bipolar nebulae are the result of optical effects and any physical modeling of these nebulae has to take these factors into consideration.

  20. The discovery of a highly polarized bipolar nebula

    International Nuclear Information System (INIS)

    Wolstencroft, R.D.; Scarrott, S.M.; Menzies, J.

    1989-01-01

    During a search for the optical counterparts of IRAS sources whose flux peaks at 25 microns, a small faint bipolar nebula was discovered in Monoceros at the position of IRAS 07131-0147. The CCD images display the object's considerable structure. The central star seems relatively free of closeby nebulosity: the two lobes have a bow-tie structure with those parts nearest to the star consisting of series of small knots. The outer parts of the lobes seem to be made up of filaments streaming away from knots. On the basis of its optical spectrum, the central star was classified as a M5-6 giant. In the IRAS color classification scheme of Van der Veen and Habing (1988), the central star is VIb which indicates that there are distinct hot and cold components of circumstellar dust and that the mass loss process may have temporarily abated. Therefore, it is proposed that the object is in the post main sequence stage of evolution and is a protoplanetary nebulae. Young protoplanetary nebulae have totally obscured central stars illuminating reflective lobes whereas older ones such as M2-9 have lobes seen in emission from gas ionized by the central hot star which is clearly visible. Since the central object of IRAS07131-0147 is a relatively unobscured late type star and the lobes are seen only by reflection, it is suggested that this nebula is a protoplanetary nebula in an evolutionary stage intermediate between that of CRL2688 and M2-9

  1. A symmetric bipolar nebula around MWC 922.

    Science.gov (United States)

    Tuthill, P G; Lloyd, J P

    2007-04-13

    We report regular and symmetric structure around dust-enshrouded Be star MWC 922 obtained with infrared imaging. Biconical lobes that appear nearly square in aspect, forming this "Red Square" nebula, are crossed by a series of rungs that terminate in bright knots or "vortices," and an equatorial dark band crossing the core delimits twin hyperbolic arcs. The intricate yet cleanly constructed forms that comprise the skeleton of the object argue for minimal perturbation from global turbulent or chaotic effects. We also report the presence of a linear comb structure, which may arise from optically projected shadows of a periodic feature in the inner regions, such as corrugations in the rim of a circumstellar disk. The sequence of nested polar rings draws comparison with the triple-ring system seen around the only naked-eye supernova in recent history: SN1987A.

  2. The blue supergiant MN18 and its bipolar circumstellar nebula

    Science.gov (United States)

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

    2015-11-01

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

  3. New and misclassified planetary nebulae

    International Nuclear Information System (INIS)

    Kohoutek, L.

    1978-01-01

    Since the 'Catalogue of Galactic Planetary Nebulae' 226 new objects have been classified as planetary nebulae. They are summarized in the form of designations, names, coordinates and the references to the discovery. Further 9 new objects have been added and called 'proto-planetary nebulae', but their status is still uncertain. Only 34 objects have been included in the present list of misclassified planetary nebulae although the number of doubtful cases is much larger. (Auth.)

  4. Single rotating stars and the formation of bipolar planetary nebula

    Energy Technology Data Exchange (ETDEWEB)

    García-Segura, G. [Instituto de Astronomía, Universidad Nacional Autónoma de Mexico, Km. 103 Carr. Tijuana-Ensenada, 22860 Ensenada, B. C. (Mexico); Villaver, E. [Departamento de Física Teórica, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Langer, N. [Argelander-Institut für Astronomie, Universität Bonn, D-53121 Bonn (Germany); Yoon, S.-C. [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul, 151-747 (Korea, Republic of); Manchado, A., E-mail: ggs@astrosen.unam.mx [Instituto de Astrofísica de Canarias, Via Láctea s/n, E-38200 La Laguna, Tenerife (Spain)

    2014-03-10

    We have computed new stellar evolution models that include the effects of rotation and magnetic torques under different hypotheses. The goal is to test whether a single star can sustain the rotational velocities needed in the envelope for magnetohydrodynamical(MHD) simulations to shape bipolar planetary nebulae (PNe) when high mass-loss rates take place. Stellar evolution models with main sequence masses of 2.5 and 5 M {sub ☉} and initial rotational velocities of 250 km s{sup –1} have been followed through the PNe formation phase. We find that stellar cores have to be spun down using magnetic torques in order to reproduce the rotation rates observed for white dwarfs. During the asymptotic giant branch phase and beyond, the magnetic braking of the core has a practically null effect on increasing the rotational velocity of the envelope since the stellar angular momentum is efficiently removed by the wind. We have also tested the best possible case scenarios in rather non-physical contexts to give enough angular momentum to the envelope. We find that we cannot get the envelope of a single star to rotate at the speeds needed for MHD simulations to form bipolar PNe. We conclude that single stellar rotators are unlikely to be the progenitors of bipolar PNe under the current MHD model paradigm.

  5. VLA observations of a highly symmetric OH maser in a bipolar nebula

    International Nuclear Information System (INIS)

    Morris, M.; Bowers, P.F.; Turner, B.E.

    1982-01-01

    The Very Large Array was used to map 1667 MHz OH maser emission from the bipolar nebula OH 231.8+4.2 at 23 distinct velocities within the unusual, 100 km s -1 wide profile. The source is large (approx.10''equivalent3 x 10 17 cm) and well resolved, and displays ordered large-scale velocity gradients. At most velocities, the maser maps display an unmistakable symmetry about the bipolar axis defined by the optical and infrared reflection nebulae. Most of the data can be accounted for by an axisymmetric model in which the measuring OH is concentrated toward the system's equatorial plane and is expanding radially away from the central star. The observation of complete rings of maser emission at some velocities, however, shows that the maser is also present at high latitudes above the equatorial plane. A model which incorporates these features plus other known aspects of bipolar nebulae is presented and discussed

  6. From red giants to planetary nebulae: Asymmetries, dust, and polarization

    International Nuclear Information System (INIS)

    Johnson, J.J.

    1990-01-01

    In order to investigate the development of aspherical planetary nebulae, polarimetry was obtained for a group of planetary nebulae and for objects that will evolve into planetary nebulae, i.e., red giants, late asymptotic giant branch (AGB) objects, proto-planetary nebulae, and young planetary nebulae. To study the dust around the objects in our sample, we also used data from the Infrared Astronomy Satellite (IRAS) mission. The youngest objects in our survey, red giants, had the hottest dust temperatures while planetary nebulae had the coolest. Most of the objects were intrinsically polarized, including the red giants. This indicated that the circumstellar dust shells of these objects were aspherical. Both carbon- and oxygen-rich objects could be intrinsically polarized. The intrinsic polarizations of a sample of our objects were modeled using an ellipsoidal circumstellar dust shell. The findings of this study suggest that the asphericities that lead to an aspherical planetary nebula originate when a red giant begins to undergo mass loss. The polarization and thus the asphericity as the star evolves, with both reaching a maximum during the proto-planetary nebula stage. The circumstellar dust shell will dissipate after the proto-planetary nebulae stage since no new material is being added. The polarization of planetary nebulae will thus be low. In the most evolved planetary nebulae, the dust has either been destroyed or dissipated into the interstellar medium. In these objects no polarization was observed

  7. Discovery of a parsec-scale bipolar nebula around MWC 349A

    Science.gov (United States)

    Gvaramadze, V. V.; Menten, K. M.

    2012-05-01

    We report the discovery of a bipolar nebula around the peculiar emission-line star MWC 349A using archival Spitzer Space Telescope 24 μm data. The nebula extends over several arcminutes (up to 5 pc) and has the same orientation and geometry as the well-known subarcsecond-scale (~400 times smaller) bipolar radio nebula associated with this star. We discuss the physical relationship between MWC 349A and the nearby B0 III star MWC 349B and propose that both stars were members of a hierarchical triple system, which was ejected from the core of the Cyg OB2 association several Myr ago and recently was dissolved into a binary system (now MWC 349A) and a single unbound star (MWC 349B). Our proposal implies that MWC 349A is an evolved massive star (likely a luminous blue variable) in a binary system with a low-mass star. A possible origin of the bipolar nebula around MWC 349A is discussed.

  8. Near-infrared imaging polarimetry of bipolar nebulae: Pt. 1

    International Nuclear Information System (INIS)

    Minchin, N.R.; Hough, J.H.; McCall, A.; Burton, M.G.; McCaughrean, M.J.; Aspin, C.; Bailey, J.A.; Axon, D.J.; Sato, Shuji

    1991-01-01

    New high-spatial-resolution polarization images of the BN-KL region of OMC-1 from 1.25-3.6 μm are presented. At the longer wavelengths these show a centro-symmetric polarization vector pattern, centred mainly on IRc2, and high degrees of polarization across the nebula, confirming that the diffuse nebulosity is dominated by the scattering of radiation, mainly from IRc2. Degrees of polarization, position angles and magnitudes are given for the observable IRc sources. These are discussed. (author)

  9. PROTO-PLANETARY DISK CHEMISTRY RECORDED BY D-RICH ORGANIC RADICALS IN CARBONACEOUS CHONDRITES

    International Nuclear Information System (INIS)

    Remusat, Laurent; Robert, Francois; Meibom, Anders; Mostefaoui, Smail; Delpoux, Olivier; Binet, Laurent; Gourier, Didier; Derenne, Sylvie

    2009-01-01

    Insoluble organic matter (IOM) in primitive carbonaceous meteorites has preserved its chemical composition and isotopic heterogeneity since the solar system formed ∼4.567 billion years ago. We have identified the carrier moieties of isotopically anomalous hydrogen in IOM isolated from the Orgueil carbonaceous chondrite. Data from high spatial resolution, quantitative isotopic NanoSIMS mapping of Orgueil IOM combined with data from electron paramagnetic resonance spectroscopy reveals that organic radicals hold all the deuterium excess (relative to the bulk IOM) in distinct, micrometer-sized, D-rich hotspots. Taken together with previous work, the results indicate that an isotopic exchange reaction took place between pre-existing organic compounds characterized by low D/H ratios and D-rich gaseous molecules, such as H 2 D + or HD 2 + . This exchange reaction most likely took place in the diffuse outer regions of the proto-planetary disk around the young Sun, offering a model that reconciles meteoritic and cometary isotopic compositions of organic molecules.

  10. Proto-Planetary Disk Chemistry Recorded by D-Rich Organic Radicals in Carbonaceous Chondrites

    Science.gov (United States)

    Remusat, Laurent; Robert, François; Meibom, Anders; Mostefaoui, Smail; Delpoux, Olivier; Binet, Laurent; Gourier, Didier; Derenne, Sylvie

    2009-06-01

    Insoluble organic matter (IOM) in primitive carbonaceous meteorites has preserved its chemical composition and isotopic heterogeneity since the solar system formed ~4.567 billion years ago. We have identified the carrier moieties of isotopically anomalous hydrogen in IOM isolated from the Orgueil carbonaceous chondrite. Data from high spatial resolution, quantitative isotopic NanoSIMS mapping of Orgueil IOM combined with data from electron paramagnetic resonance spectroscopy reveals that organic radicals hold all the deuterium excess (relative to the bulk IOM) in distinct, micrometer-sized, D-rich hotspots. Taken together with previous work, the results indicate that an isotopic exchange reaction took place between pre-existing organic compounds characterized by low D/H ratios and D-rich gaseous molecules, such as H2D+ or HD2 +. This exchange reaction most likely took place in the diffuse outer regions of the proto-planetary disk around the young Sun, offering a model that reconciles meteoritic and cometary isotopic compositions of organic molecules.

  11. Mass outflow in the nearby proto-planetary system, Beta Pictoris

    International Nuclear Information System (INIS)

    Bruhweiler, F.C.; Grady, C.A.; Kondo, Yoji

    1991-01-01

    Previous spectral studies of circumstallar dust around the nearby, candidate proto-planetary system, Beta Pictoris, has detected only infalling gas. The lack of detectable mass outflow has been critical in the interpretation of the origin of the circumstellar gas and in our understanding of the evolutionary status of the Beta Pictoris system. IUE high-dispersion spectra are presented which show, in addition to infall, the presence of mass outflow, with a maximum observed outflow velocity of -60 km/s, and a corresponding instantaneous outflow rate of 1.1 x 10 to the -14th solar mass/yr, or 1.1 x 10 to the -11th Jupiter mass/yr. This mass outflow rate and terminal velocity are comparable to the magnitudes of mass infall rates and terminal velocities observed from late 1986 through early 1988. The implications of these observations on our understanding of the mechanisms producing infall from the surrounding circumstellar disk are discussed, as are the implications for our understanding of the evolutionary status of the Beta Pic system. 23 refs

  12. Pushing the limits: detecting H2 emission from faint bipolar planetary nebulae in the IPHAS sample

    Science.gov (United States)

    Ramos-Larios, G.; Guerrero, M. A.; Sabin, L.; Santamaría, E.

    2017-09-01

    We have obtained deep narrowband images in the near-infrared H2 λ2.122 μm emission line for a sample of 15 faint Isaac Newton Telescope Photometric H α Survey (IPHAS) bipolar planetary nebulae (PNe) to search for molecular material. H2 emission is found in most of them (14 out of 15), mostly associated with rings at their equatorial regions and with their bipolar lobes. These detections add to the high occurrence of H2 emission among bipolar PNe reported in previous works, resulting from the large reservoir of molecular material in these sources and the suitable excitation conditions for H2 emission. The correlation between detailed bipolar morphology and H2 luminosity is also confirmed: bipolar PNe with broad equatorial rings (R-BPNe) have almost no continuum emission, are H2 brighter and have larger H2/Br γ line ratio than bipolar PNe with pinched equatorial waists (W-BPNe). The origin of this dichotomy is unclear. The larger size and age of R-BPNe are consistent with shock excitation of H2, whereas ultraviolet pumping is most likely the excitation mechanism in the smaller and younger W-BPNe, which would explain their lower H2 luminosity. Although both types of bipolar PNe seem to proceed from the same progenitor population, this does not imply that R-BPNe descend from W-BPNe. Otherwise, we note that some of the H2-weak bipolar PNe harbor post-common envelope binary systems and symbiotic stars. Finally, we suggest that the long-living H2 emission from R-BPNe arises from a discrete distribution of compact knots embedded within the ionized gas at the equatorial region.

  13. DISCOVERY OF COLLIMATED BIPOLAR OUTFLOWS IN THE PLANETARY NEBULA TH 2-A

    Energy Technology Data Exchange (ETDEWEB)

    Danehkar, A., E-mail: ashkbiz.danehkar@cfa.harvard.edu [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia)

    2015-12-10

    We present a comprehensive set of spatially resolved, integral field spectroscopic mapping of the Wolf–Rayet planetary nebula Th 2-A, obtained using the Wide Field Spectrograph on the Australian National University 2.3-m telescope. Velocity-resolved Hα channel maps with a resolution of 20 km s{sup −1} allow us to identify different kinematic components within the nebula. This information is used to develop a three-dimensional morpho-kinematic model of the nebula using the interactive kinematic modeling tool shape. These results suggest that Th 2-A has a thick toroidal shell with an expansion velocity of 40 ± 10 km s{sup −1}, and a thin prolate ellipsoid with collimated bipolar outflows toward its axis reaching velocities in the range of 70–110 km s{sup −1}, with respect to the central star. The relationship between its morpho-kinematic structure and peculiar [WO]-type stellar characteristics deserves further investigation.

  14. Morphology of the bipolar planetary nebula NGC 2346 from emission line profile studies

    Energy Technology Data Exchange (ETDEWEB)

    Anandarao, B G; Banerjee, D P.K.; Desai, J N; Jain, S K; Mallik, D C.V.

    1988-11-01

    High resolution observations of H..cap alpha.. 6563 A, (O III) 5007 A and (N II) 6583 A emission lines in the bipolar planetary nebula NGC 2346 are presented. Expansion velocities (V/sub exp/) of 8 +- 1 km s/sup -1/ in the :O III: line and 11 +- 1 km s/sup -1/ in the :N II: line are observed in the central region. An expansion velocity of 7.5 +- 1.0 km s/sup -1/ in the (O III) line is observed in a position 10 arcsec away from the centre, in the NE lobe of the nebula. From the widths of the H..cap alpha.. and (N II) lines, an ion temperature of T=10 650 +- 2950 K and a turbulent velocity V/sub T/ = 16 +- 2 km s/sup -1/ are derived. Using the detailed radial velocity mapping done by a previous author, a morphological model for the nebula is presented.

  15. BUBBLES AND KNOTS IN THE KINEMATICAL STRUCTURE OF THE BIPOLAR PLANETARY NEBULA NGC 2818

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, Roberto, E-mail: vazquez@astro.unam.mx [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Km 103 Carretera Tijuana-Ensenada, 22860 Ensenada, BC (Mexico)

    2012-06-01

    High-resolution Hubble Space Telescope archive imaging and high-dispersion spectroscopy are used to study the complex morphological and kinematical structure of the planetary nebula, NGC 2818. We analyze narrowband H{alpha}, [O III], [N II], [S II], and He II images, addressing important morphological features. Ground-based long-slit echelle spectra were obtained crossing NGC 2818 at five different positions to precisely determine kinematical features in the structure of the nebula. A distance of 2.5 kpc was used to determine physical scales. Constructing models to fit the data with modern computational tools, we find NGC 2818 is composed of (1) a non-uniform bipolar structure with a semimajor axis of 0.92 pc (75''), possibly deformed by the stellar wind, (2) a 0.17 pc (14'') diameter central region, which is potentially the remnant of an equatorial enhancement, and (3) a great number of cometary knots. These knots are preferentially located inside a radius of 0.24 pc (20'') around the central star. The major axis of the main structure is oriented at i {approx_equal} 60 Degree-Sign with respect to the line of sight and at P.A. = +89 Degree-Sign on the plane of the sky. Expansion velocities of this nebula are V{sub pol} = 105 km s{sup -1} and V{sub eq} = 20 km s{sup -1}, which lead to our estimate of the kinematical age of {tau}{sub k} {approx_equal} 8400 {+-} 3400 yr (assuming homologous expansion). Our observations do not support the idea that high-velocity collimated ejections are responsible for the formation of microstructures inside the nebula. We determine the systemic velocity of NGC 2818 to be V{sub HEL} = +26 {+-} 2 km s{sup -1}.

  16. Mid-infrared imaging of the bipolar planetary nebula M2-9 from SOFIA

    Energy Technology Data Exchange (ETDEWEB)

    Werner, M. W.; Sahai, R.; Davis, J.; Livingston, J. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91107 (United States); Lykou, F. [Institute for Astronomy, University of Vienna, Turkenschanzstrasse 17, A-1180, Vienna (Austria); DE Buizer, J. [USRA SOFIA Science Center, M/S 211-3, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Morris, M. R. [Division of Astronomy, P.O. Box 951547, UCLA, Los Angeles, CA 90095 (United States); Keller, L. [Department of Physics, Ithaca College, Ithaca, NY 14850 (United States); Adams, J.; Gull, G.; Henderson, C.; Herter, T.; Schoenwald, J., E-mail: Michael.W.Werner@jpl.nasa.gov [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States)

    2014-01-10

    We have imaged the bipolar planetary nebula M2-9 using SOFIA's FORCAST instrument in six wavelength bands between 6.6 and 37.1 μm. A bright central point source, unresolved with SOFIA's ∼4''-5'' beam, is seen at each wavelength, and the extended bipolar lobes are clearly seen at 19.7 μm and beyond. The photometry between 10 and 25 μm is well fit by the emission predicted from a stratified disk seen at large inclination, as has been proposed for this source by Lykou et al. and by Smith and Gehrz. The principal new results in this paper relate to the distribution and properties of the dust that emits the infrared radiation. In particular, a considerable fraction of this material is spread uniformly through the lobes, although the dust density does increase at the sharp outer edge seen in higher resolution optical images of M2-9. The dust grain population in the lobes shows that small (<0.1 μm) and large (>1 μm) particles appear to be present in roughly equal amounts by mass. We suggest that collisional processing within the bipolar outflow plays an important role in establishing the particle size distribution.

  17. Mid-infrared imaging of the bipolar planetary nebula M2-9 from SOFIA

    International Nuclear Information System (INIS)

    Werner, M. W.; Sahai, R.; Davis, J.; Livingston, J.; Lykou, F.; DE Buizer, J.; Morris, M. R.; Keller, L.; Adams, J.; Gull, G.; Henderson, C.; Herter, T.; Schoenwald, J.

    2014-01-01

    We have imaged the bipolar planetary nebula M2-9 using SOFIA's FORCAST instrument in six wavelength bands between 6.6 and 37.1 μm. A bright central point source, unresolved with SOFIA's ∼4''-5'' beam, is seen at each wavelength, and the extended bipolar lobes are clearly seen at 19.7 μm and beyond. The photometry between 10 and 25 μm is well fit by the emission predicted from a stratified disk seen at large inclination, as has been proposed for this source by Lykou et al. and by Smith and Gehrz. The principal new results in this paper relate to the distribution and properties of the dust that emits the infrared radiation. In particular, a considerable fraction of this material is spread uniformly through the lobes, although the dust density does increase at the sharp outer edge seen in higher resolution optical images of M2-9. The dust grain population in the lobes shows that small (<0.1 μm) and large (>1 μm) particles appear to be present in roughly equal amounts by mass. We suggest that collisional processing within the bipolar outflow plays an important role in establishing the particle size distribution.

  18. IUE observations of new A star candidate proto-planetary systems

    Science.gov (United States)

    Grady, Carol A.

    1994-01-01

    As a result of the detection of accreting gas in the A5e PMS Herbig Ae star, HR 5999, most of the observations for this IUE program were devoted to Herbig Ae stars rather than to main sequence A stars. Mid-UV emission at optical minimum light was detected for UX Ori (A1e), BF Ori (A5e), and CQ Tau (F2e). The presence of accreting gas in HD 45677 and HD 50138 prompted reclassification of these stars as Herbig Be stars rather than as protoplanetary nebulae. Detailed results are discussed.

  19. Nature vs. Nurture: The influence of OB star environments on proto-planetary disk evolution

    Science.gov (United States)

    Bouwman, Jeroen

    2006-09-01

    We propose a combined IRAC/IRS study of a large, well-defined and unbiased X-ray selected sample of pre-main-sequence stars in three OB associations: Pismis 24 in NGC 6357, NGC 2244 in the Rosette Nebula, and IC 1795 in the W3 complex. The samples are based on recent Chandra X-ray Observatory studies which reliably identify hundreds of cluster members and were carefully chosen to avoid high infrared nebular background. A new Chandra exposure of IC 1795 is requested, and an optical followup to characterise the host stars is planned.

  20. ROTATING STARS AND THE FORMATION OF BIPOLAR PLANETARY NEBULAE. II. TIDAL SPIN-UP

    Energy Technology Data Exchange (ETDEWEB)

    García-Segura, G. [Instituto de Astronomía, Universidad Nacional Autónoma de Mexico, Km. 103 Carr. Tijuana-Ensenada, 22860, Ensenada, B. C. (Mexico); Villaver, E. [Departamento de Física Teórica, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Manchado, A. [Instituto de Astrofísica de Canarias, Via Láctea s/n, E-38200 La Laguna, Tenerife (Spain); Langer, N. [Argelander-Institut für Astronomie, Universität Bonn, D-53121 Bonn (Germany); Yoon, S.-C., E-mail: ggs@astrosen.unam.mx [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul, 151-747 (Korea, Republic of)

    2016-06-01

    We present new binary stellar evolution models that include the effects of tidal forces, rotation, and magnetic torques with the goal of testing planetary nebulae (PNs) shaping via binary interaction. We explore whether tidal interaction with a companion can spin-up the asymptotic giant brach (AGB) envelope. To do so, we have selected binary systems with main-sequence masses of 2.5 M {sub ⊙} and 0.8 M {sub ⊙} and evolve them allowing initial separations of 5, 6, 7, and 8 au. The binary stellar evolution models have been computed all the way to the PNs formation phase or until Roche lobe overflow (RLOF) is reached, whatever happens first. We show that with initial separations of 7 and 8 au, the binary avoids entering into RLOF, and the AGB star reaches moderate rotational velocities at the surface (∼3.5 and ∼2 km s{sup −1}, respectively) during the inter-pulse phases, but after the thermal pulses it drops to a final rotational velocity of only ∼0.03 km s{sup −1}. For the closest binary separations explored, 5 and 6 au, the AGB star reaches rotational velocities of ∼6 and ∼4 km s{sup −1}, respectively, when the RLOF is initiated. We conclude that the detached binary models that avoid entering the RLOF phase during the AGB will not shape bipolar PNs, since the acquired angular momentum is lost via the wind during the last two thermal pulses. This study rules out tidal spin-up in non-contact binaries as a sufficient condition to form bipolar PNs.

  1. THE PHYSICAL ENVIRONMENT AROUND IRAS 17599–2148: INFRARED DARK CLOUD AND BIPOLAR NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    Dewangan, L. K.; Janardhan, P. [Physical Research Laboratory, Navrangpura, Ahmedabad 380 009 (India); Ojha, D. K. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005 (India); Zinchenko, I. [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov st., Nizhny Novgorod 603950 (Russian Federation); Ghosh, S. K. [National Centre for Radio Astrophysics, Ganeshkhind, Pune 411 007 (India); Luna, A., E-mail: lokeshd@prl.res.in [Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis Enrique Erro # 1, Tonantzintla, Puebla, C.P. 72840 (Mexico)

    2016-12-20

    We present a multiscale and multiwavelength study to investigate the star formation process around IRAS 17599–2148, which is part of an elongated filamentary structure (EFS) (extension ∼21 pc) seen in the Herschel maps. Using the Herschel data analysis, at least six massive clumps (M {sub clump} ∼ 777–7024 M {sub ⊙}) are found in the EFS with a range of temperature and column density of ∼16–39 K and ∼(0.6–11) × 10{sup 22} cm{sup −2} (A {sub V}  ∼ 7–117 mag), respectively. The EFS hosts cold gas regions (i.e., infrared dark cloud) without any radio detection and a bipolar nebula (BN) linked with the H ii region IRAS 17599–2148, tracing two distinct environments inferred through the temperature distribution and ionized emission. Based on virial analysis and higher values of self-gravitating pressure, the clumps are found unstable against gravitational collapse. We find 474 young stellar objects (YSOs) in the selected region, and ∼72% of these YSOs are found in the clusters distributed mainly toward the clumps in the EFS. These YSOs might have spontaneously formed due to processes not related to the expanding H ii region. At the edges of BN, four additional clumps are also associated with YSO clusters, which appear to be influenced by the expanding H ii region. The most massive clump in the EFS contains two compact radio sources traced in the Giant Metre-wave Radio Telescope 1.28 GHz map and a massive protostar candidate, IRS 1, prior to an ultracompact H ii phase. Using the Very Large Telescope/NACO near-infrared images, IRS 1 is resolved with a jet-like feature within a 4200 au scale.

  2. The spectrophotometry and chemical composition of the oxygen-poor bipolar nebula NGC 6164-5

    Science.gov (United States)

    Dufour, Reginald J.; Parker, Robert A. R.; Henize, Karl G.

    1988-01-01

    The paper presents new ground-based and IUE spectrophotometry of several positions in NGC 6164-5 surrounding the Population I Of star HD 148937. Electron temperatures, densities, and abundances are derived for the various positions in the nebula using spectral line information. For all of the regions observed, Ne/H is depleted by an amount comparable to O/H, while S/H and Ar/H have normal values. The results suggest that the nebula consists partly of material ejected from inner shell-burning regions of the Of star. In effect, HD 148937 is older and more advanced than what was previously thought.

  3. Spectrophotometry and chemical composition of the oxygen-poor bipolar nebula NGC 6164-5

    International Nuclear Information System (INIS)

    Dufour, R.J.; Parker, R.A.R.; Henize, K.G.

    1988-01-01

    The paper presents new ground-based and IUE spectrophotometry of several positions in NGC 6164-5 surrounding the Population I Of star HD 148937. Electron temperatures, densities, and abundances are derived for the various positions in the nebula using spectral line information. For all of the regions observed, Ne/H is depleted by an amount comparable to O/H, while S/H and Ar/H have normal values. The results suggest that the nebula consists partly of material ejected from inner shell-burning regions of the Of star. In effect, HD 148937 is older and more advanced than what was previously thought. 34 references

  4. He II Raman Scattered Line by Neutral Hydrogen in the Bipolar Platenary Nebula M2-9

    Directory of Open Access Journals (Sweden)

    Hee-Won Lee

    2001-06-01

    Full Text Available In the spectrum of the young bipolar planetary nebula M2-9 obtained from the 1.5 m telescope at the Cerro Tololo Inter-American Observatory, we detected the He~II feature at 6545 Å that are proposed to be formed via Raman scattering by atomic hydrogen. However, in the same spectrum, the He~II emission lines at 6527 Å and 6560 Å are absent, which implies that the He~II emission region is hidden from our line of sight and that the H~I scattering region is pretty much extended not to be obscured entirely. We performed photoionization computations to estimate the physical size of the He~II emission line region to be 1016 cm, from which the location and dimension of the obscuring circumstellar region are inferred and the temperature of the central star must exceed 105 K. The angular size of the circumstellar region responsible for the obscuration of the He~II emission region is ~ 1'' with the assumption of the distance 01 kpc to M2-9, which is consistent with the recent image of M2-9 obtained with the Hubble Space Telescope.

  5. AN EXTREME HIGH-VELOCITY BIPOLAR OUTFLOW IN THE PRE-PLANETARY NEBULA IRAS 08005-2356

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, R. [Jet Propulsion Laboratory, California Institute of Technology, MS 183-900, Pasadena, CA 91109 (United States); Patel, N. A., E-mail: raghvendra.sahai@jpl.nasa.gov [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

    2015-09-01

    We report interferometric mapping of the bipolar pre-planetary nebula IRAS 08005-2356 (I 08005) with an angular resolution of ∼1″–5″, using the Submillimeter Array, in the {sup 12}CO J = 2–1, 3–2, {sup 13}CO J = 2–1, and SiO J = 5–4 (v = 0) lines. Single-dish observations, using the SMT 10 m, were made in these lines as well as in the CO J = 4–3 and SiO J = 6–5 (v = 0) lines. The line profiles are very broad, showing the presence of a massive (>0.1 M{sub ⊙}), extreme high velocity outflow (V ∼ 200 km s{sup −1}) directed along the nebular symmetry axis derived from the Hubble Space Telescope imaging of this object. The outflow's scalar momentum far exceeds that available from radiation pressure of the central post-AGB star, and it may be launched from an accretion disk around a main-sequence companion. We provide indirect evidence for such a disk from its previously published, broad Hα emission profile, which we propose results from Lyβ emission generated in the disk followed by Raman-scattering in the innermost regions of a fast, neutral wind.

  6. Theoretical investigation into the existence of molecules in planetary nebulae

    International Nuclear Information System (INIS)

    Carlson, W.J.

    1980-01-01

    Calculations of chemical kinetic equilibrium molecular abundances in the neutral regions of planetary nebulae are presented. The development of these abundances during the expansion of the nebula is calculated. The physical parameters in the neutral regions following the formation of the nebula by the ejection of the envelope of a long peiod variable star have been taken from available dynamical models. Similarly, the temperature and luminosity of the central star as a function of time have been taken from available theoretical calculations. The thermal equilibrium has been solved independently. The temperatures in the shell and later in the condensations which develop are in the range from 30 to 250 K. Number densities range from 10 7 for the youngest model calculated to 2 x 10 4 for neutral condensations in a 10,000 year old nebula. It is shown that, for a typical nebula containing 0.2 Msub solar, molecules are expected to be the dominant form for only a short period early in the expansion phase. Subsequently, the condensations are not sufficiently optically thick to permit the continued existence of a preponderance of molecules. The molecular abundances in the later models are similar to those in diffuse interstellar clouds. The expectation arising from those results is that little molecular material will be injected into the interstellar medium by planetary nebulae. There is, however, a remarkable resemblance between the conditions in the model calculated at very early stages of the expansion and conditions deduced from observations for proto-planetary nebulae

  7. Infrared nebula in the Chamaeleon T association

    International Nuclear Information System (INIS)

    Schwartz, R.D.; Henize, K.G.

    1983-01-01

    Data are tabulated for seven nebulae in the Chamaeleon T association. Three, which are large and clearly related to illuminating stars, appear to be typical reflection nebulae. Three are small wisps attached to stars and are probably cometary-type reflection nebulae. The remaining nebula is a triangular wisp having an unusually red spectral energy distribution and showing no illuminating star on visual wavelength photographs. The western tip of this nebula coincides closely with the position of a recently reported infrared source. The nebula is probably one lobe of a bipolar nebula

  8. A Shocking Solar Nebula?

    OpenAIRE

    Liffman, Kurt

    2009-01-01

    It has been suggested that shock waves in the solar nebula formed the high temperature materials observed in meteorites and comets. It is shown that the temperatures at the inner rim of the solar nebula could have been high enough over a sufficient length of time to produce chondrules, CAIs, refractory dust grains and other high-temperature materials observed in comets and meteorites. The solar bipolar jet flow may have produced an enrichment of 16O in the solar nebula over time and the chond...

  9. ALMA Observations of the Water Fountain Pre-Planetary Nebula IRAS 16342-3814: High-Velocity Bipolar Jets and an Expanding Torus.

    Science.gov (United States)

    Sahai, R; Vlemmings, W H T; Gledhill, T; Sánchez Contreras, C; Lagadec, E; Nyman, L-Å; Quintana-Lacaci, G

    2017-01-20

    We have mapped 12 CO J=3-2 and other molecular lines from the "water-fountain" bipolar pre-planetary nebula (PPN) IRAS 16342-3814 with [Formula: see text] resolution using ALMA. We find (i) two very high-speed knotty, jet-like molecular outflows, (ii) a central high-density (> few × 10 6 cm -3 ), expanding torus of diameter 1300 AU, and (iii) the circumstellar envelope of the progenitor AGB, generated by a sudden, very large increase in the mass-loss rate to > 3.5 × 10 -4 M ⊙ yr -1 in the past ~455 yr. Strong continuum emission at 0.89 mm from a central source (690 mJy), if due to thermally-emitting dust, implies a substantial mass (0.017 M ⊙ ) of very large (~mm-sized) grains. The measured expansion ages of the above structural components imply that the torus (age~160 yr) and the younger high-velocity outflow (age~110 yr) were formed soon after the sharp increase in the AGB mass-loss rate. Assuming a binary model for the jets in IRAS 16342, the high momentum rate for the dominant jet-outflow in IRAS 16342 implies a high minimum accretion rate, ruling out standard Bondi-Hoyle-Lyttleton wind accretion and wind Roche lobe overflow (RLOF) models with white-dwarf or main-sequence companions. Most likely, enhanced RLOF from the primary or accretion modes operating within common envelope evolution are needed.

  10. Registration of H2O and SiO masers in the Calabash Nebula to confirm the planetary nebula paradigm

    Science.gov (United States)

    Dodson, R.; Rioja, M.; Bujarrabal, V.; Kim, J.; Cho, S. H.; Choi, Y. K.; Youngjoo, Y.

    2018-05-01

    We report on the astrometric registration of very long baseline interferometry images of the SiO and H2O masers in OH 231.8+4.2, the iconic proto-planetary nebula also known as the Calabash nebula, using the Korean VLBI Network and source frequency phase referencing. This, for the first time, robustly confirms the alignment of the SiO masers, close to the asymptotic giant branch star, driving the bilobe structure with the water masers in the outflow. We are able to trace the bulk motions for the H2O masers over the last few decades to be 19 km s-1 and deduce that the age of this expansion stage is 38 ± 2 yr. The combination of this result with the distance allows a full 3D reconstruction and confirms that the H2O masers lie on and expand along the known large-scale symmetry axis and that the outflow is only a few decades old, so mass loss is almost certainly ongoing. Therefore, we conclude that the SiO emission marks the stellar core of the nebular, the H2O emission traces the expansion, and there must be multiple epochs of ejection to drive the macro-scale structure.

  11. Planetary nebulae

    International Nuclear Information System (INIS)

    Amnuehl', P.R.

    1985-01-01

    The history of planetary nebulae discovery and their origin and evolution studies is discussed in a popular way. The problem of planetary nebulae central star is considered. The connection between the white-draft star and the planetary nebulae formulation is shown. The experimental data available acknowledge the hypothesis of red giant - planetary nebula nucleus - white-draft star transition process. Masses of planetary nebulae white-draft stars and central stars are distributed practically similarly: the medium mass is close to 0.6Msub(Sun) (Msub(Sun) - is the mass of the Sun)

  12. Gaseous nebulae

    International Nuclear Information System (INIS)

    Williams, R.E.

    1976-01-01

    Gaseous nebulae are large, tenuous clouds of ionized gas that are associated with hot stars and that emit visible light because of the energy that they receive from the ultraviolet radiation of the stars. Examples include H II regions, planetary nebulae, and nova/supernova remnants. The emphasis is on the physical processes that occur in gaseous nebulae as opposed to a study of the objects themselves. The introduction discusses thermodynamic vs. steady-state equilibrium and excitation conditions in a dilute radiation field. Subsequent sections take up important atomic processes in gaseous nebulae (particle--particle collision rates, radiative interaction rates, cross sections), the ionization equilibrium (sizes of H II regions, ionization of the heavier elements), kinetic temperature and energy balance (heating of the electrons, cooling of the electrons), and the spectra of gaseous nebulae (line fluxes in nebulae). 7 figures, 5 tables

  13. Proto-planetary disc evolution and dispersal

    Science.gov (United States)

    Rosotti, Giovanni Pietro

    2015-05-01

    Planets form from gas and dust discs in orbit around young stars. The timescale for planet formation is constrained by the lifetime of these discs. The properties of the formed planetary systems depend thus on the evolution and final dispersal of the discs, which is the main topic of this thesis. Observations reveal the existence of a class of discs called "transitional", which lack dust in their inner regions. They are thought to be the last stage before the complete disc dispersal, and hence they may provide the key to understanding the mechanisms behind disc evolution. X-ray photoevaporation and planet formation have been studied as possible physical mechanisms responsible for the final dispersal of discs. However up to now, these two phenomena have been studied separately, neglecting any possible feedback or interaction. In this thesis we have investigated what is the interplay between these two processes. We show that the presence of a giant planet in a photo-evaporating disc can significantly shorten its lifetime, by cutting the inner regions from the mass reservoir in the exterior of the disc. This mechanism produces transition discs that for a given mass accretion rate have larger holes than in models considering only X-ray photo-evaporation, constituting a possible route to the formation of accreting transition discs with large holes. These discs are found in observations and still constitute a puzzle for the theory. Inclusion of the phenomenon called "thermal sweeping", a violent instability that can destroy a whole disc in as little as 10 4 years, shows that the outer disc left can be very short-lived (depending on the X-ray luminosity of the star), possibly explaining why very few non accreting transition discs are observed. However the mechanism does not seem to be efficient enough to reconcile with observations. In this thesis we also show that X-ray photo-evaporation naturally explains the observed correlation between stellar masses and accretion rates and is therefore the ideal candidate for driving disc evolution. Another process that can influence discs is a close encounter with another star. In this thesis we develop a model to study the effect of stellar dynamics in the natal stellar cluster on the discs, following for the first time at the same time the stellar dynamics together with the evolution of the discs. We find that, although close encounters with stars are unlikely to change significantly the mass of a disc, they can change substantially its size, hence imposing an upper limit on the observed disc radii. Finally, we investigated in this thesis whether discs can be reformed after their dispersal. If a star happens to be in a region that is currently forming stars, it can accrete material from the interstellar medium. This mechanism may result in the production of "second generation" discs such that in a given star forming region a few percent of stars may still possess a disc, in tentative agreement with observations of so called "old accretors", which are difficult to explain within the current paradigm of disc evolution and dispersal.

  14. Observing nebulae

    CERN Document Server

    Griffiths, Martin

    2016-01-01

    This book enables anyone with suitable instruments to undertake an examination of nebulae and see or photograph them in detail. Nebulae, ethereal clouds of gas and dust, are among the most beautiful objects to view in the night sky. These star-forming regions are a common target for observers and photographers. Griffiths describes many of the brightest and best nebulae and includes some challenges for the more experienced observer. Readers learn the many interesting astrophysical properties of these clouds, which are an important subject of study in astronomy and astrobiology. Non-mathematical in approach, the text is easily accessible to anyone with an interest in the subject. A special feature is the inclusion of an observational guide to 70 objects personally observed or imaged by the author. The guide also includes photographs of each object for ease of identification along with their celestial coordinates, magnitudes and other pertinent information. Observing Nebulae provides a ready resource to allow an...

  15. Abundance in the planetary nebulae NGC 6537 and He2-111

    NARCIS (Netherlands)

    Pottasch, [No Value; Beintema, DA; Feibelman, WA

    2000-01-01

    The ISO and IUE spectra of the bipolar planetary nebulae NGC 6537 and He2-111 are presented. These spectra are combined with the spectrum in the visual wavelength region from the nebulae to obtain a complete spectrum that is corrected for extinction. The chemical abundance of the nebulae is then

  16. Influence of stellar duplicity on the form of planetary nebulae

    International Nuclear Information System (INIS)

    Kolesnik, I.G.; Pilyugin, L.S.

    1986-01-01

    Formation of planetary nebulae's spatial structures is considered. Simple expression for angular distribution of density in planetary nebulae is obtained. Bipolar structures are formed effectively in binary systems in which the velocity of the expanding shell around the main star is smaller than the orbital velocity of the satellite. Masses of satellites lie in the range 0.1-0.4Msub(sun). Theoretical isophotal contour map for the model of the planetary nebula NGC 3587 is consistent with observational data. It is shown that central stars of planetary nebulae are usually binary systems

  17. THE SHAPING EFFECT OF COLLIMATED FAST OUTFLOWS IN THE EGG NEBULA

    International Nuclear Information System (INIS)

    Dinh-V-Trung; Lim, Jeremy

    2009-01-01

    We present high angular resolution observations of the HC 3 N J = 5-4 line from the Egg nebula, which is the archetype of proto-planetary nebulae (PPNs). We find that the HC 3 N emission in the approaching and receding portion of the envelope traces a clumpy hollow shell, similar to that seen in normal carbon-rich envelopes. Near the systemic velocity, the hollow shell is fragmented into several large blobs or arcs with missing portions correspond spatially to locations of previously reported high-velocity outflows in the Egg nebula. This provides direct evidence for the disruption of the slowly expanding envelope ejected during the AGB phase by the collimated fast outflows initiated during the transition to the PPN phase. From modeling the HC 3 N distribution, we could reproduce qualitatively the spatial kinematics of the HC 3 N J = 5-4 emission using a HC 3 N shell with two pairs of cavities cleared by the collimated high-velocity outflows along the polar direction and in the equatorial plane. We infer a relatively high abundance of HC 3 N/H 2 ∼ 3 x 10 -6 for an estimated mass-loss rate of 3 x 10 -5 M sun yr -1 in the HC 3 N shell. The high abundance of HC 3 N and the presence of some weaker J = 5-4 emission in the vicinity of the central post-AGB star suggest an unusually efficient formation of this molecule in the Egg nebula.

  18. The Search for Binaries in Post-Asymptotic Giant Branch Stars: Do Binary Companions Shape the Nebulae?

    Directory of Open Access Journals (Sweden)

    Bruce J. Hrivnak

    2012-03-01

    Full Text Available Binary companions are often invoked to explain the axial and point symmetry seen in the majority of planetary nebulae and proto-planetary nebulae (PPNs. To explore this hypothesis, we have undertaken a long-term (20 year study of light and velocity variations in PPNs. From the photometric study of 24 PPNs, we find that all vary in brightness, and from a subset of 12 carbon-rich PPNs of F-G spectral type we find periods of 35-155 days, with the cooler having the longer periods. The variations are seen to be due to pulsation; no photometric evidence for binarity is seen. A radial velocity study of a sub-sample of seven of the brightest of these shows that they all vary with the pulsation periods. Only one shows evidence of a longer-term variation that we tentatively identify as being due to a binary companion. We conclude that the present evidence for the binary nature of these PPNs is meager and that any undetected companions of these PPNs must be of low mass ( 30 years.

  19. Shaping of planetary nebulae

    International Nuclear Information System (INIS)

    Balick, B.

    1987-01-01

    The phases of stellar evolution and the development of planetary nebulae are examined. The relation between planetary nebulae and red giants is studied. Spherical and nonspherical cases of shaping planetaries with stellar winds are described. CCD images of nebulae are analyzed, and it is determined that the shape of planetary nebulae depends on ionization levels. Consideration is given to calculating the distances of planetaries using radio images, and molecular hydrogen envelopes which support the wind-shaping model of planetary nebulae

  20. Three-Dimensional Adaptive Mesh Refinement Simulations of Point-Symmetric Nebulae

    NARCIS (Netherlands)

    Rijkhorst, E.-J.; Icke, V.; Mellema, G.; Meixner, M.; Kastner, J.H.; Balick, B.; Soker, N.

    2004-01-01

    Previous analytical and numerical work shows that the generalized interacting stellar winds model can explain the observed bipolar shapes of planetary nebulae very well. However, many circumstellar nebulae have a multipolar or point-symmetric shape. With two-dimensional calculations, Icke showed

  1. The Crab Nebula

    International Nuclear Information System (INIS)

    Mitton, S.

    1979-01-01

    The subject is covered in chapters, as follows: A.D.1054, a star explodes (historical account of observations of the supernova of which the Crab Nebula is the remnant); the telescope takes over (discovery and subsequent observation of the Crab Nebula); the message of the fiery remnant (detailed structure and its interpretation); the invisible nebula (electromagnetic radiation from the Crab Nebula and its interpretation); a beacon in the night (the discovery of pulsars, with special reference to the pulsar in the Crab Nebula; observation and theory); the strange world of a neutron star (theory, prediction and observation); magnetic fields and energy flow from the pulsar (stellar magnetosphere; luminosity of the nebula); how does the pulsar pulse (observation; models to explain beaming); outburst and aftermath (types of supernovae and their evolution; nucleosynthesis); supernovae and their remnants (account of observations since early records); the Crab Nebula and modern astronomy. (U.K.)

  2. Dust in planetary nebulae

    International Nuclear Information System (INIS)

    Kwok, S.

    1980-01-01

    A two-component dust model is suggested to explain the infrared emission from planetary nebulae. A cold dust component located in the extensive remnant of the red-giant envelope exterior to the visible nebula is responsible for the far-infrared emission. A ward dust component, which is condensed after the formation of the planetary nebula and confined within the ionized gas shell, emits most of the near- and mid-infrared radiation. The observations of NGC 7027 are shown to be consisten with such a model. The correlation of silicate emission in several planetary nebulae with an approximately +1 spectral index at low radio frequencies suggests that both the silicate and radio emissions originate from the remnant of the circumstellar envelope of th precursor star and are observable only while the planetary nebula is young. It is argued that oxygen-rich stars as well as carbon-rich stars can be progenitors of planetary nebulae

  3. Dust in planetary nebulae

    International Nuclear Information System (INIS)

    Mathis, J.S.

    1978-01-01

    The author's review concentrates on theoretical aspects of dust in planetary nebulae (PN). He considers the questions: how much dust is there is PN; what is its composition; what effects does it have on the ionization structure, on the dynamics of the nebula. (Auth.)

  4. Nebulae and interstellar matter

    International Nuclear Information System (INIS)

    1987-01-01

    The South African Astronomical Observatory (SAAO) has investigated the IRAS source 1912+172. This source appears to be a young planetary nebula with a binary central star. During 1986 SAAO has also studied the following: hydrogen deficient planetary nebulae; high speed flows in HII regions, and the wavelength dependence of interstellar polarization. 2 figs

  5. Dust in Proto-Planetary Disks: Properties and Evolution

    OpenAIRE

    Natta, A.; Testi, L.; Calvet, N.; Henning, Th.; Waters, R.; Wilner, D.

    2006-01-01

    We review the properties of dust in protoplanetary disks around optically visible pre-main sequence stars obtained with a variety of observational techniques, from measurements of scattered light at visual and infrared wavelengths to mid-infrared spectroscopy and millimeter interferometry. A general result is that grains in disks are on average much larger than in the diffuse interstellar medium (ISM). In many disks, there is evidence that a large mass of dust is in grains with millimeter and...

  6. Charge transfer in astrophysical nebulae

    International Nuclear Information System (INIS)

    Shields, G.A.

    1990-01-01

    Charge transfer has become a standard ingredient in models of ionized nebulae, supernovae remnants and active galactic nuclei. Charge transfer rate coefficients and the physics of ionized nebulae are considered. Charge transfer is applied to the ionization structure and line emission of ionized nebulae. Photoionized nebulae observations are used to test theoretical predictions of charge transfer rates. (author)

  7. Wolf-Rayet nebulae

    International Nuclear Information System (INIS)

    Chu, You-Hua

    2016-01-01

    Since the discovery of nebulae around Wolf-Rayet (WR) stars in the 1960s, it has been established that WR stars are massive stars at advanced evolutionary stages and that their surrounding nebulae result from the interactions between the stellar mass loss and the ambient interstellar medium. Surveys of WR nebulae have been made in the Galaxy, Magellanic Clouds, and other nearby galaxies in the Local Group. Some WR nebulae exhibit He II λ4686 line emission, indicating stellar effective temperatures of 90 — 100 x 10 3 K. The shocked fast stellar winds from WR nebulae have been detected in soft X-rays, but theoretical models have not been able to reproduce the observed X-ray spectral properties. Elemental abundances of WR nebulae consisting of synthesized stellar material can constrain stellar evolution models, but high-dispersion spectra are needed to kinematically separate the expanding shell of a WR nebula and the background interstellar medium for accurate abundance analyses. (paper)

  8. Bipolar Disorder

    Science.gov (United States)

    Bipolar disorder is a serious mental illness. People who have it go through unusual mood changes. They go ... The down feeling is depression. The causes of bipolar disorder aren't always clear. It runs in families. ...

  9. Structure of planetary nebulae

    International Nuclear Information System (INIS)

    Goad, L.E.

    1975-01-01

    Image-tube photographs of planetary nebulae taken through narrow-band interference filters are used to map the surface brightness of these nebulae in their most prominent emission lines. These observations are best understood in terms of a two-component model consisting of a tenuous diffuse nebular medium and a network of dense knots and filaments with neutral cores. The observations of the diffuse component indicate that the inner regions of these nebulae are hollow shells. This suggests that steady stellar winds are the dominant factor in determining the structure of the central regions of planetary nebulae. The observations of the filamentary components of NGC 40 and NGC 6720 show that the observed nebular features can result from the illumination of the inner edges of dense fragmentary neutral filaments by the central stars of these nebulae. From the analysis of the observations of the low-excitation lines in NGC 2392, it is concluded that the rate constant for the N + --H charge transfer reaction is less than 10 -12 cm 3 sec -1

  10. A Tactile Carina Nebula

    Science.gov (United States)

    Grice, Noreen A.; Mutchler, M.

    2010-01-01

    Astronomy was once considered a science restricted to fully sighted participants. But in the past two decades, accessible books with large print/Braille and touchable pictures have brought astronomy and space science to the hands and mind's eye of students, regardless of their visual ability. A new universally-designed tactile image featuring the Hubble mosaic of the Carina Nebula is being presented at this conference. The original dataset was obtained with Hubble's Advanced Camera for Surveys (ACS) hydrogen-alpha filter in 2005. It became an instant icon after being infused with additional color information from ground-based CTIO data, and released as Hubble's 17th anniversary image. Our tactile Carina Nebula promotes multi-mode learning about the entire life-cycle of stars, which is dramatically illustrated in this Hubble mosaic. When combined with descriptive text in print and Braille, the visual and tactile components seamlessly reach both sighted and blind populations. Specific touchable features of the tactile image identify the shapes and orientations of objects in the Carina Nebula that include star-forming regions, jets, pillars, dark and light globules, star clusters, shocks/bubbles, the Keyhole Nebula, and stellar death (Eta Carinae). Visit our poster paper to touch the Carina Nebula!

  11. The filamentary nebulae S 188

    International Nuclear Information System (INIS)

    Rosado, M.; Kwitter, K.B.

    1982-01-01

    The crescent shaped nebula S 188 is identified as a planetary nebula (PN) of Peimbert's Type I on the basis of its observed nebula spectrum. New FP interferometric work allows to determine the systemic motion of this nebula. The derived kinematical distance exceeds Cudworth's distance estimate supporting the idea that Peimbert's Type I PNs have larger ejected masses than typical PNs. A discussion about the origin of its non-spherical shape is also given. (author)

  12. Bipolar disorders

    DEFF Research Database (Denmark)

    Vieta, Eduard; Berk, Michael; Schulze, Thomas G

    2018-01-01

    Bipolar disorders are chronic and recurrent disorders that affect >1% of the global population. Bipolar disorders are leading causes of disability in young people as they can lead to cognitive and functional impairment and increased mortality, particularly from suicide and cardiovascular disease...... and accurate diagnosis is difficult in clinical practice as the onset of bipolar disorder is commonly characterized by nonspecific symptoms, mood lability or a depressive episode, which can be similar in presentation to unipolar depression. Moreover, patients and their families do not always understand...... a bipolar disorder from other conditions. Optimal early treatment of patients with evidence-based medication (typically mood stabilizers and antipsychotics) and psychosocial strategies is necessary....

  13. Dynamos in asymptotic-giant-branch stars as the origin of magnetic fields shaping planetary nebulae.

    Science.gov (United States)

    Blackman, E G; Frank, A; Markiel, J A; Thomas, J H; Van Horn, H M

    2001-01-25

    Planetary nebulae are thought to be formed when a slow wind from the progenitor giant star is overtaken by a subsequent fast wind generated as the star enters its white dwarf stage. A shock forms near the boundary between the winds, creating the relatively dense shell characteristic of a planetary nebula. A spherically symmetric wind will produce a spherically symmetric shell, yet over half of known planetary nebulae are not spherical; rather, they are elliptical or bipolar in shape. A magnetic field could launch and collimate a bipolar outflow, but the origin of such a field has hitherto been unclear, and some previous work has even suggested that a field could not be generated. Here we show that an asymptotic-giant-branch (AGB) star can indeed generate a strong magnetic field, having as its origin a dynamo at the interface between the rapidly rotating core and the more slowly rotating envelope of the star. The fields are strong enough to shape the bipolar outflows that produce the observed bipolar planetary nebulae. Magnetic braking of the stellar core during this process may also explain the puzzlingly slow rotation of most white dwarf stars.

  14. Bipolar Disorder.

    Science.gov (United States)

    Spearing, Melissa

    Bipolar disorder, a brain disorder that causes unusual shifts in a person's mood, affects approximately one percent of the population. It commonly occurs in late adolescence and is often unrecognized. The diagnosis of bipolar disorder is made on the basis of symptoms, course of illness, and when possible, family history. Thoughts of suicide are…

  15. Polarization due to dust scattering in the planetary nebula Cn1-1

    International Nuclear Information System (INIS)

    Bhatt, H.C.

    1989-01-01

    The peculiar emission-line object Cn1-1 (=HDE330036=PK330+4 degrees 1), classified both as a symbiotic star and as a planetary nebula, was detected by the Infrared Astronomical Satellite (IRAS) as a strong source of far-infrared dust in the system. Bhatt and Mallik (1986) discussed the nature of the dust in Cn1-1 and argued that the object is a Type I protoplanetary nebula in a binary system. The argument presented here is that the polarization is intrinsic to Cn1-1 and is due to scattering by large (compared to interstellar) dust grains in the protoplanetary nebula that are asymmetrically distributed around the central star. The large degree of polarization (approximately 3 percent for the Cn1-1 distance of approximately 450 pc) with a large lambda(sub max) is naturally explained if it is caused by scattering by large dust grains in the Cn1-1 nebula. Since the H(sub alpha) line is also polarized at the same level and position angle as the continuum, the dust must be asymmetrically distributed around the central star. The morphology of the protoplanetary nebula in Cn1-1 may be bipolar. Thus, the polarization observations support the suggestion that Cn1-1 is a bipolar Type I planetary nebula

  16. Modelling pulsar wind nebulae

    CERN Document Server

    2017-01-01

    In view of the current and forthcoming observational data on pulsar wind nebulae, this book offers an assessment of the theoretical state of the art of modelling them. The expert authors also review the observational status of the field and provide an outlook for future developments. During the last few years, significant progress on the study of pulsar wind nebulae (PWNe) has been attained both from a theoretical and an observational perspective, perhaps focusing on the closest, more energetic, and best studied nebula: the Crab, which appears in the cover. Now, the number of TeV detected PWNe is similar to the number of characterized nebulae observed at other frequencies over decades of observations. And in just a few years, the Cherenkov Telescope Array will increase this number to several hundreds, actually providing an essentially complete account of TeV emitting PWNe in the Galaxy. At the other end of the multi-frequency spectrum, the SKA and its pathfinder instruments, will reveal thousands of new pulsa...

  17. Can planetary nebulae rotate

    International Nuclear Information System (INIS)

    Grinin, V.P.

    1982-01-01

    It is shown that the inclination of spectral lines observed in a number of planetary nebulae when the spectrograph slit is placed along the major axis, which is presently ascribed to nonuniform expansion of the shells, actually may be due to rotation of the nebulae about their minor axes, as Campbell and Moore have suggested in their reports. It is assumed that the rotation of the central star (or, if the core is a binary system, circular motions of gas along quasi-Keplerian orbits) serves as the source of the original rotation of a protoplanetary nebula. The mechanism providing for strengthening of the original rotation in the process of expansion of the shell is the tangential pressure of L/sub α/ radiation due to the anisotropic properties of the medium and radiation field. The dynamic effect produced by them is evidently greatest in the epoch when the optical depth of the nebula in the L/sub c/ continuum becomes on the order of unity in the course of its expansion

  18. Large-Scale Structure of the Carina Nebula.

    Science.gov (United States)

    Smith; Egan; Carey; Price; Morse; Price

    2000-04-01

    Observations obtained with the Midcourse Space Experiment (MSX) satellite reveal for the first time the complex mid-infrared morphology of the entire Carina Nebula (NGC 3372). On the largest size scale of approximately 100 pc, the thermal infrared emission from the giant H ii region delineates one coherent structure: a (somewhat distorted) bipolar nebula with the major axis perpendicular to the Galactic plane. The Carina Nebula is usually described as an evolved H ii region that is no longer actively forming stars, clearing away the last vestiges of its natal molecular cloud. However, the MSX observations presented here reveal numerous embedded infrared sources that are good candidates for sites of current star formation. Several compact infrared sources are located at the heads of dust pillars or in dark globules behind ionization fronts. Because their morphology suggests a strong interaction with the peculiar collection of massive stars in the nebula, we speculate that these new infrared sources may be sites of triggered star formation in NGC 3372.

  19. Millimeter-wave molecular line observations of the Tornado nebula

    International Nuclear Information System (INIS)

    Sakai, D.; Oka, T.; Tanaka, K.; Matsumura, S.; Miura, K.; Takekawa, S.

    2014-01-01

    We report the results of millimeter-wave molecular line observations of the Tornado Nebula (G357.7-0.1), which is a bright radio source behind the Galactic center region. A 15' × 15' area was mapped in the J = 1-0 lines of CO, 13 CO, and HCO + with the Nobeyama Radio Observatory 45 m telescope. The Very Large Array archival data of OH at 1720 MHz were also reanalyzed. We found two molecular clouds with separate velocities, V LSR = –14 km s –1 and +5 km s –1 . These clouds show rough spatial anti-correlation. Both clouds are associated with OH 1720 MHz emissions in the area overlapping with the Tornado Nebula. The spatial and velocity coincidence indicates violent interaction between the clouds and the Tornado Nebula. Modestly excited gas prefers the position of the Tornado 'head' in the –14 km s –1 cloud, also suggesting the interaction. Virial analysis shows that the +5 km s –1 cloud is more tightly bound by self-gravity than the –14 km s –1 cloud. We propose a formation scenario for the Tornado Nebula; the +5 km s –1 cloud collided into the –14 km s –1 cloud, generating a high-density layer behind the shock front, which activates a putative compact object by Bondi-Hoyle-Lyttleton accretion to eject a pair of bipolar jets.

  20. SHAPING THE GLOWING EYE PLANETARY NEBULA, NGC 6751

    International Nuclear Information System (INIS)

    Clark, D. M.; Garcia-Diaz, Ma. T.; Lopez, J. A.; Steffen, W. G.; Richer, M. G.

    2010-01-01

    NGC 6751 is a highly structured multiple-shell planetary nebula (PN) with a bipolar outflow. In this work, we present a comprehensive set of spatially resolved, high spectral resolution, long-slit spectra and deep imaging from San Pedro Martir, Gemini, the Hα composite full sky survey and archive images from the Hubble Space Telescope and Spitzer. This material allows us to identify all the main morphological components and study their detailed kinematics. We find a thick equatorial structure fragmented into multiple knots that enclose a fast expanding bubble with a filamentary surface structure. The knotty ring is surrounded by faint emission from a disk-like envelope. Lobes with embedded filaments form a bipolar outflow. The equatorial ring is tilted with respect to the line of sight and with respect to the bipolar outflow. A spherical halo surrounds the PN and there is material further out identified as a fragmented outer halo. This information is used to derive a three-dimensional morpho-kinematic model using the code SHAPE that closely replicates the observed image and long-slit spectra of the nebula, providing a fair representation of its complex structure. NGC 6751 is located close to the galactic plane and its large-scale surrounding environment is shown to be a gas-rich region. We find indications that the PN is interacting with the interstellar medium. Emission components from an extended nebulosity located a couple of arcminutes away from the nebula have radial velocities that are inconsistent with the rest of NGC 6751 and are confirmed as originating from the ambient material, not related to the PN, in agreement with a previous suggestion.

  1. Hydrodynamics of Antisymmetric Nebulae

    NARCIS (Netherlands)

    Icke, V.; Meixner, M.; Kastner, J.H.; Balick, B.; Soker, N.

    2004-01-01

    Balick's `generalized interacting stellar winds' model posits that the bipolar shape of most PNe is due to the interaction between a very fast tenuous outflow, and a disk-shaped denser atmosphere left over from an earlier slow phase of mass loss. Analytical and numerical work shows that this

  2. Review of solar nebula models

    International Nuclear Information System (INIS)

    Wood, J.A.; Morfill, G.E.

    1988-01-01

    The major changes that have occurred in thinking about protosolar nebula models are discussed. The concept favored by astrophysicists for the last decade, that of a viscous accretion-disk nebula, is examined. The properties of recent accretion-disk models that are most relevant to chondrite-forming processes are noted. 27 references

  3. Magnetic fields and star formation: evidence from imaging polarimetry of the Serpens Reflection Nebula

    Energy Technology Data Exchange (ETDEWEB)

    Warren-Smith, R F; Draper, P W; Scarrott, S M

    1987-08-01

    CCD imaging of the Serpens bipolar reflection nebula shows it to be surrounded by dark material having spiral density structure. Multi-colour polarization mapping also reveals details of the surrounding magnetic field, indicating that this also has spiral structure. These observations are discussed along with current ideas about the role of magnetic fields during star formation. An interpretation involving the non-axisymmetric magnetically braked collapse of a protostellar cloud is proposed and a resulting magnetic field configuration is described which can account for the observations. Evidence is also discussed for the formation of a binary star system within the nebula, resulting from the fragmentation of a magnetized protostellar disc.

  4. Ghost Head Nebula

    Science.gov (United States)

    1999-01-01

    Looking like a colorful holiday card, a new image from NASA's Hubble Space Telescope reveals a vibrant green and red nebula far from Earth. The image of NGC 2080, taken by Hubble's Wide Field and Planetary Camera 2, designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif., is available online at http://www.jpl.nasa.gov/images/wfpc . Images like this help astronomers investigate star formation in nebulas. NGC 2080, nicknamed 'The Ghost Head Nebula,' is one of a chain of star-forming regions lying south of the 30 Doradus nebula in the Large Magellanic Cloud. 30 Doradus is the largest star-forming complex in the local group of galaxies. This 'enhanced color' picture is composed of three narrow-band-filter images obtained by Hubble on March 28, 2000. The red and blue light come from regions of hydrogen gas heated by nearby stars. The green light on the left comes from glowing oxygen. The energy to illuminate the green light is supplied by a powerful stellar wind, a stream of high-speed particles coming from a massive star just outside the image. The central white region is a combination of all three emissions and indicates a core of hot, massive stars in this star-formation region. Intense emission from these stars has carved a bowl-shaped cavity in surrounding gas. In the white region, the two bright areas (the 'eyes of the ghost') - named A1 (left) and A2 (right) -- are very hot, glowing 'blobs' of hydrogen and oxygen. The bubble in A1 is produced by the hot, intense radiation and powerful stellar wind from one massive star. A2 contains more dust and several hidden, massive stars. The massive stars in A1 and A2 must have formed within the last 10,000 years, since their natal gas shrouds are not yet disrupted by the powerful radiation of the newborn stars. The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract with the Goddard Space Flight Center, Greenbelt, Md. The

  5. Bipolar Disorder

    Science.gov (United States)

    ... one or other traumatic event Drug or alcohol abuse Complications Left untreated, bipolar disorder can result in serious problems that affect every area of your life, such as: Problems related to drug and alcohol use Suicide or suicide attempts Legal or financial problems Damaged ...

  6. Observations of the planetary nebula RWT 152 with OSIRIS/GTC

    Science.gov (United States)

    Aller, A.; Miranda, L. F.; Olguín, L.; Solano, E.; Ulla, A.

    2016-11-01

    RWT 152 is one of the few known planetary nebulae with an sdO central star. We present subarcsecond red tunable filter Hα imaging and intermediate-resolution, long-slit spectroscopy of RWT 152 obtained with OSIRIS/GTC (Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy/Gran Telescopio Canarias) with the goal of analysing its properties. The Hα image reveals a bipolar nebula with a bright equatorial region and multiple bubbles in the main lobes. A faint circular halo surrounds the main nebula. The nebular spectra reveal a very low excitation nebula with weak emission lines from H+, He+ and double-ionized metals, and absence of emission lines from neutral and single-ionized metals, except for an extremely faint [N II] λ6584 emission line. These spectra may be explained if RWT 152 is a density-bounded planetary nebula. Low nebular chemical abundances of S, O, Ar, N and Ne are obtained in RWT 152, which, together with the derived high peculiar velocity (˜ 92-131 km s-1), indicate that this object is a halo planetary nebula. The available data are consistent with RWT 152 evolving from a low-mass progenitor (˜1 M⊙) formed in a metal-poor environment.

  7. Neutrality in bipolar structures

    DEFF Research Database (Denmark)

    Montero, Javier; Rodríguez, J. Tinguaro; Franco, Camilo

    2014-01-01

    In this paper, we want to stress that bipolar knowledge representation naturally allows a family of middle states which define as a consequence different kinds of bipolar structures. These bipolar structures are deeply related to the three types of bipolarity introduced by Dubois and Prade, but our...... approach offers a systematic explanation of how such bipolar structures appear and can be identified....

  8. Bipolar Treatment: Are Bipolar I and Bipolar II Treated Differently?

    Science.gov (United States)

    ... The diagnosis and management of bipolar I and bipolar II disorders: Clinical practice update. Mayo Clinic Proceedings. 2017;92:1532. Haynes PL, et al. Social rhythm therapies for mood disorders: An update. Current Psychiatry Reports. ...

  9. ALMA OBSERVATIONS OF THE COLDEST PLACE IN THE UNIVERSE: THE BOOMERANG NEBULA

    International Nuclear Information System (INIS)

    Sahai, R.; Vlemmings, W. H. T.; Huggins, P. J.; Nyman, L.-Å.; Gonidakis, I.

    2013-01-01

    The Boomerang Nebula is the coldest known object in the universe, and an extreme member of the class of pre-planetary nebulae, objects which represent a short-lived transitional phase between the asymptotic giant branch and planetary nebula evolutionary stages. Previous single-dish CO (J = 1-0) observations (with a 45'' beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang Nebula with ALMA in the CO J = 2-1 and J = 1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with the Hubble Space Telescope and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter and visible wavelengths. The large diffuse biconical shape of the nebula seen in the visible wavelength range is likely due to preferential illumination of the cold, high-velocity outflow. We find a compact source of millimeter-wave continuum in the nebular waist—these data, together with sensitive upper limits on the radio continuum using observations with ATCA, indicate the presence of a substantial mass of very large (millimeter-sized) grains in the waist of the nebula. Another unanticipated result is the detection of CO emission regions beyond the ultra-cold region which indicate the re-warming of the cold gas, most likely due to photoelectric grain heating

  10. ALMA Observations of the Coldest Place in the Universe: The Boomerang Nebula

    Science.gov (United States)

    Sahai, R.; Vlemmings, W. H. T.; Huggins, P. J.; Nyman, L.-Å.; Gonidakis, I.

    2013-11-01

    The Boomerang Nebula is the coldest known object in the universe, and an extreme member of the class of pre-planetary nebulae, objects which represent a short-lived transitional phase between the asymptotic giant branch and planetary nebula evolutionary stages. Previous single-dish CO (J = 1-0) observations (with a 45'' beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang Nebula with ALMA in the CO J = 2-1 and J = 1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with the Hubble Space Telescope and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter and visible wavelengths. The large diffuse biconical shape of the nebula seen in the visible wavelength range is likely due to preferential illumination of the cold, high-velocity outflow. We find a compact source of millimeter-wave continuum in the nebular waist—these data, together with sensitive upper limits on the radio continuum using observations with ATCA, indicate the presence of a substantial mass of very large (millimeter-sized) grains in the waist of the nebula. Another unanticipated result is the detection of CO emission regions beyond the ultra-cold region which indicate the re-warming of the cold gas, most likely due to photoelectric grain heating.

  11. ALMA OBSERVATIONS OF THE COLDEST PLACE IN THE UNIVERSE: THE BOOMERANG NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, R. [Jet Propulsion Laboratory, MS 183-900, California Institute of Technology, Pasadena, CA 91109 (United States); Vlemmings, W. H. T. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala (Sweden); Huggins, P. J. [Physics Department, New York University, 4 Washington Place, New York, NY 10003 (United States); Nyman, L.-Å. [Joint ALMA Observatory (JAO), Alonso de Cordova 3107, Vitacura, Santiago de Chile (Chile); Gonidakis, I., E-mail: raghvendra.sahai@jpl.nasa.gov [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Marsfield NSW 2122 (Australia)

    2013-11-10

    The Boomerang Nebula is the coldest known object in the universe, and an extreme member of the class of pre-planetary nebulae, objects which represent a short-lived transitional phase between the asymptotic giant branch and planetary nebula evolutionary stages. Previous single-dish CO (J = 1-0) observations (with a 45'' beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang Nebula with ALMA in the CO J = 2-1 and J = 1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with the Hubble Space Telescope and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter and visible wavelengths. The large diffuse biconical shape of the nebula seen in the visible wavelength range is likely due to preferential illumination of the cold, high-velocity outflow. We find a compact source of millimeter-wave continuum in the nebular waist—these data, together with sensitive upper limits on the radio continuum using observations with ATCA, indicate the presence of a substantial mass of very large (millimeter-sized) grains in the waist of the nebula. Another unanticipated result is the detection of CO emission regions beyond the ultra-cold region which indicate the re-warming of the cold gas, most likely due to photoelectric grain heating.

  12. Bipolar electrochemistry.

    Science.gov (United States)

    Fosdick, Stephen E; Knust, Kyle N; Scida, Karen; Crooks, Richard M

    2013-09-27

    A bipolar electrode (BPE) is an electrically conductive material that promotes electrochemical reactions at its extremities (poles) even in the absence of a direct ohmic contact. More specifically, when sufficient voltage is applied to an electrolyte solution in which a BPE is immersed, the potential difference between the BPE and the solution drives oxidation and reduction reactions. Because no direct electrical connection is required to activate redox reactions, large arrays of electrodes can be controlled with just a single DC power supply or even a battery. The wireless aspect of BPEs also makes it possible to electrosynthesize and screen novel materials for a wide variety of applications. Finally, bipolar electrochemistry enables mobile electrodes, dubbed microswimmers, that are able to move freely in solution. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Transtorno bipolar

    Directory of Open Access Journals (Sweden)

    Alda Martin

    1999-01-01

    Full Text Available Os resultados de estudos de famílias sugerem que o transtorno bipolar tenha uma base genética. Essa hipótese foi reforçada em estudos de adoção e de gêmeos. A herança do transtorno bipolar é complexa, envolve vários genes, além de apresentar heterogeneidade e interação entre fatores genéticos e não-genéticos. Achados, que já foram replicados, já implicaram os cromossomos 4, 12, 18 e 21, entre outros, na busca por genes de suscetibilidade. Os resultados mais promissores foram obtidos através de estudos de ligação. Por outro lado, os estudos de associação geraram dados interessantes, mas ainda vagos. Os estudos de populações de pacientes homogêneos e a melhor definição do fenótipo deverão contribuir para avanços futuros. A identificação dos genes relacionados ao transtorno bipolar irá permitir o melhor entendimento e tratamento dessa doença.

  14. The Orion Nebula: The Jewel in the Sword

    Science.gov (United States)

    2001-01-01

    -Res - JPEG: 2273 x 2784 pix - 976k] Caption : PR Photo 03d/01 shows a small section of the observational data (in one infrared spectral band only, here reproduced in B/W) on which PR Photo 03a/01 is based. The field is centred on one of the famous Orion silhouette disks (Orion 114-426) (it is located approximately halfway between the centre and the right edge of PR Photo 03c/01 ). The dusty disk itself is seen edge-on as a dark streak against the background emission of the Orion Nebula, while the bright fuzzy patches on either side betray the presence of the embedded parent star that illuminates tenuous collections of dust above its north and south poles to create these small reflection nebulae. Recent HST studies suggest that the very young Orion 114-426 disk - that is thirty times bigger than our present-day Solar System - may already be showing signs of forming its own proto-planetary system. Technical information about this photo is available below. It is even possible to see disks of dust and gas surrounding a few of the young stars, as silhouettes in projection against the bright background of the nebula. Many of these disks are very small and usually only seen on images obtained with the Hubble Space Telescope (HST) [2]. However, under the best seeing conditions on Paranal, the sharpness of VLT images at infrared wavelengths approaches that of the HST in this spectral band, revealing some of these disks, as shown in PR Photo 03d/01 . Indeed, the theoretical image sharpness of the 8.2-m VLT is more than three times better than that of the 2.4-m HST. Thus, the VLT will soon yield images of small regions with even higher resolution by means of the High-Resolution Near-Infrared Camera (CONICA) and the Nasmyth Adaptive Optics System (NAOS) that will compensate the smearing effect introduced by the turbulence in the atmosphere. Later on, extremely sharp images will be obtained when all four VLT telescopes are combined to form the Very Large Telescope Interferometer (VLTI

  15. DIFFERENTIAL PROPER-MOTION MEASUREMENTS OF THE CYGNUS EGG NEBULA: THE PRESENCE OF EQUATORIAL OUTFLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Ueta, Toshiya; Tomasino, Rachael L. [Department of Physics and Astronomy, MS 6900, University of Denver, Denver, CO 80208 (United States); Ferguson, Brian A. [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

    2013-08-01

    We present the results of differential proper-motion analyses of the Egg Nebula (RAFGL 2688, V1610 Cyg) based on the archived two-epoch optical data taken with the Hubble Space Telescope. First, we determined that the polarization characteristics of the Egg Nebula are influenced by the higher optical depth of the central regions of the nebula (i.e., the 'dustsphere' of {approx}10{sup 3} AU radius), causing the nebula to illuminate in two steps-the direct starlight is first channeled into bipolar cavities and then scattered off to the rest of the nebula. We then measured the amount of motion of local structures and the signature concentric arcs by determining their relative shifts over the 7.25 yr interval. Based on our analysis, which does not rely on the single-scattering assumption, we concluded that the lobes have been excavated by a linear expansion along the bipolar axis for the past {approx}400 yr, while the concentric arcs have been generated continuously and moving out radially at about 10 km s{sup -1} for the past {approx}5500 yr, and there appears to be a colatitudinally increasing trend in the radial expansion velocity field of the concentric arcs. Numerical investigations into the mass-loss modulation by the central binary system exist, which predict such a colatitudinally increasing expansion velocity field in the spiral-shock trails of the mass-loss ejecta. Therefore, the Egg Nebula may represent a rare edge-on case of the binary-modulated circumstellar environs, corroborating the previous theoretical predictions.

  16. Millimeter-wave molecular line observations of the Tornado nebula

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, D. [Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Oka, T.; Tanaka, K.; Matsumura, S.; Miura, K.; Takekawa, S., E-mail: sakai.daisuke@nao.ac.jp [Department of Physics, Institute of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama, Kanagawa 223-8522 (Japan)

    2014-08-10

    We report the results of millimeter-wave molecular line observations of the Tornado Nebula (G357.7-0.1), which is a bright radio source behind the Galactic center region. A 15' × 15' area was mapped in the J = 1-0 lines of CO, {sup 13}CO, and HCO{sup +} with the Nobeyama Radio Observatory 45 m telescope. The Very Large Array archival data of OH at 1720 MHz were also reanalyzed. We found two molecular clouds with separate velocities, V{sub LSR} = –14 km s{sup –1} and +5 km s{sup –1}. These clouds show rough spatial anti-correlation. Both clouds are associated with OH 1720 MHz emissions in the area overlapping with the Tornado Nebula. The spatial and velocity coincidence indicates violent interaction between the clouds and the Tornado Nebula. Modestly excited gas prefers the position of the Tornado 'head' in the –14 km s{sup –1} cloud, also suggesting the interaction. Virial analysis shows that the +5 km s{sup –1} cloud is more tightly bound by self-gravity than the –14 km s{sup –1} cloud. We propose a formation scenario for the Tornado Nebula; the +5 km s{sup –1} cloud collided into the –14 km s{sup –1} cloud, generating a high-density layer behind the shock front, which activates a putative compact object by Bondi-Hoyle-Lyttleton accretion to eject a pair of bipolar jets.

  17. Red giants as precursors of planetary nebulae

    International Nuclear Information System (INIS)

    Renzini, A.

    1981-01-01

    It is generally accepted that Planetary Nebulae are produced by asymptotic giant-branch stars. Therefore, several properties of planetary nebulae are discussed in the framework of the current theory of stellar evolution. (Auth.)

  18. A Study of Planetary Nebulae using the Faint Object Infrared Camera for the SOFIA Telescope

    Science.gov (United States)

    Davis, Jessica

    2012-01-01

    A planetary nebula is formed following an intermediate-mass (1-8 solar M) star's evolution off of the main sequence; it undergoes a phase of mass loss whereby the stellar envelope is ejected and the core is converted into a white dwarf. Planetary nebulae often display complex morphologies such as waists or torii, rings, collimated jet-like outflows, and bipolar symmetry, but exactly how these features form is unclear. To study how the distribution of dust in the interstellar medium affects their morphology, we utilize the Faint Object InfraRed CAmera for the SOFIA Telescope (FORCAST) to obtain well-resolved images of four planetary nebulae--NGC 7027, NGC 6543, M2-9, and the Frosty Leo Nebula--at wavelengths where they radiate most of their energy. We retrieve mid infrared images at wavelengths ranging from 6.3 to 37.1 micron for each of our targets. IDL (Interactive Data Language) is used to perform basic analysis. We select M2-9 to investigate further; analyzing cross sections of the southern lobe reveals a slight limb brightening effect. Modeling the dust distribution within the lobes reveals that the thickness of the lobe walls is higher than anticipated, or rather than surrounding a vacuum surrounds a low density region of tenuous dust. Further analysis of this and other planetary nebulae is needed before drawing more specific conclusions.

  19. Number of planetary nebulae in our galaxy

    International Nuclear Information System (INIS)

    Alloin, D.; Cruz-Gonzalez, C.; Peimbert, M.

    1976-01-01

    It is found that the contribution to the ionization of the interstellar medium due to planetary nebulae is from one or two orders of magnitude smaller than that due to O stars. The mass return to the interstellar medium due to planetary nebulae is investigated, and the birth rate of white dwarfs and planetary nebulae are compared. Several arguments are given against the possibility that the infrared sources detected by Becklin and Neugebauer in the direction of the galactic center are planetary nebulae

  20. The Formation of a Planetary Nebula.

    Science.gov (United States)

    Harpaz, Amos

    1991-01-01

    Proposes a scenario to describe the formation of a planetary nebula, a cloud of gas surrounding a very hot compact star. Describes the nature of a planetary nebula, the number observed to date in the Milky Way Galaxy, and the results of research on a specific nebula. (MDH)

  1. The Trifid Nebula: Stellar Sibling Rivalry

    Science.gov (United States)

    2001-01-01

    A zoom into the Trifid Nebula starts with ground-based observations and ends with a Hubble Space Telescope (HST) image. Another HST image shows star formation in the nebula and the video concludes with a ground-based image of the Trifid Nebula.

  2. Kinematics of galactic planetary nebulae

    International Nuclear Information System (INIS)

    Kiosa, M.I.; Khromov, G.S.

    1979-01-01

    The classical method of determining the components of the solar motion relative to the centroid of the system of planetary nebulae with known radial velocities is investigated. It is shown that this method is insensitive to random errors in the radial velocities and that low accuracy in determining the coordinates of the solar apex and motion results from the insufficient number of planetaries with measured radial velocities. The planetary nebulae are found not to satisfy well the law of differential galactic rotation with circular orbits. This is attributed to the elongation of their galactic orbits. A method for obtaining the statistical parallax of planetary nebulae is considered, and the parallax calculated from the tau components of their proper motion is shown to be the most reliable

  3. Contraction of the solar nebula

    International Nuclear Information System (INIS)

    Rawal, J.J.

    1984-01-01

    The concept of Roche limit is applied to the Laplacian theory of the origin of the solar system to study the contraction of a spherical gas cloud (solar nebula). In the process of contraction of the solar nebula, it is assumed that the phenomenon of supersonic turbulent convection is operative and brings about the halt at various stages of contraction. It is found that the radius of the contracting solar nebula follows the Titius-Bode law. The consequences of the relation are also discussed. The aim is to attempt to explain, on the basis of the concept of Roche limit, the distribution of planets in the solar system and try to understand the physics underlying it. (Auth.)

  4. Ultraviolet spectra of planetary nebulae

    International Nuclear Information System (INIS)

    Adams, S.; Seaton, M.J.

    1982-01-01

    Features observed in infrared spectra suggest that certain very low excitation (VLE) nebulae have low C/O abundance ratios (Cohen and Barlow 1980; Aitken and Roche 1982). Fluxes in the multiplets [O II] lambda 2470 and C II] lambda 2326 have been measured for the VLE nebula He He 2-131 = HD 138403 using IUE high-dispersion spectra. An analysis similar to that of Harrington et al. (1980) for IC 418 gives C/O = 0.3 for He 2-131, compared with C/O = 1.3 for IC 418 and 0.6 for the Sun. (author)

  5. Circumnebular neutral hydrogen in planetary nebulae

    International Nuclear Information System (INIS)

    Taylor, A.R.; Gussie, G.T.; Pottasch, S.R.

    1990-01-01

    Centimeter line observations of six compact planetary nebulae are reported. Circumnebular atomic hydrogen absorption has been observed in NGC 6790, NGC 6886, IC 418, IC 5117, and BD +30 deg 3639, while H I was not observed to a high upper limit in NGC 6741. Hydrogen was also detected in emission from BD +30 deg 3639. The expansion velocities of the circumnebular envelopes are similar to the expansion velocities observed for the ionized nebula. The optical depth of circumnebular H I appears to decrease with increasing linear radius of the ionized nebulae, indicating that these nebulae are ionization bounded and that the amount of atomic hydrogen decreases as young nebulas evolve. 28 refs

  6. From red giants to planetary nebulae

    International Nuclear Information System (INIS)

    Kwok, S.

    1982-01-01

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

  7. WR stars with ring nebulae

    International Nuclear Information System (INIS)

    Tutukov, A.

    1982-01-01

    It is shown that most of usually apparently single nitrogen WR stars with ring emission nebulae around them (WN + Neb) are a probable product of the evolution of a massive close binary with initial masses of components exceeding approximately 20 solar masses. (Auth.)

  8. Bipolar disorder in adolescence.

    Science.gov (United States)

    DeFilippis, Melissa; Wagner, Karen Dineen

    2013-08-01

    Bipolar disorder is a serious psychiatric condition that may have onset in childhood. It is important for physicians to recognize the symptoms of bipolar disorder in children and adolescents in order to accurately diagnose this illness early in its course. Evidence regarding the efficacy of various treatments is necessary to guide the management of bipolar disorder in youth. For example, several medications commonly used for adults with bipolar disorder have not shown efficacy for children and adolescents with bipolar disorder. This article reviews the prevalence, diagnosis, course, and treatment of bipolar disorder in children and adolescents and provides physicians with information that will aid in diagnosis and treatment.

  9. Evolution of planetary nebulae. III. Position-velocity images of butterfly-type nebulae

    International Nuclear Information System (INIS)

    Icke, V.; Preston, H.L.; Balick, B.

    1989-01-01

    Observations of the motions of the shells of the planetary nebulae NGC 2346, NGC 2371-2, NGC 2440, NGC 6058, NGC 6210, IC 1747, IC 5217, J-320, and M2-9 are presented. These are all 'butterfly' type PNs, and show evidence for bipolar shocks. The observations are interpreted in terms of a fast spherical wind, driven by the central star into a quasi-toroidal envelope deposited earlier by the star, during its slow-wind phase on the asymptotic giant branch. It is shown that this model, which is a straightforward extension of a mechanism previously invoked to account for elliptical PNs, reproduces the essential kinematic features of butterfly PNs. It is inferred that the envelopes of butterflies must have a considerable equator-to-pole density gradient, and it is suggested that the origin of this asphericity must be sought in an as yet unknown mechanism during the AGB, Mira, or OH/IR phases of late stellar evolution. 28 references

  10. Cytokines in bipolar disorder

    DEFF Research Database (Denmark)

    Munkholm, Klaus; Vinberg, Maj; Vedel Kessing, Lars

    2012-01-01

    BACKGROUND: Current research and hypothesis regarding the pathophysiology of bipolar disorder suggests the involvement of immune system dysfunction that is possibly related to disease activity. Our objective was to systematically review evidence of cytokine alterations in bipolar disorder according...... to affective state. METHODS: We conducted a systemtic review of studies measuring endogenous cytokine concentrations in patients with bipolar disorder and a meta-analysis, reporting results according to the PRISMA statement. RESULTS: Thirteen studies were included, comprising 556 bipolar disorder patients...

  11. (C III lambda 1909/Si III lambda 1892) ratio as a diagnostic for planetary nebulae and symbiotic stars

    International Nuclear Information System (INIS)

    Feibelman, W.A.; Aller, L.H.; California Univ., Los Angeles)

    1987-01-01

    Suitable IUE archival material on planetary nebulae has been examined to determine the log R /F(lambda 1909 C III)/F(lambda 1892 Si III)/ as a discriminant for distinguishing planetary nebulae from symbiotic stars and related objects. The mean value of log R for 73 galactic planetaries is 1.4, while that of extragalactic planetaries appears to be slightly lower, and that for symbiotics is 0.3. The lower value of log R for symbiotics is easily understood as a consequence of their higher densities. A plot of log R versus N-epsilon indicates that 80 percent of the planetaries fall into the range of log R between 1.2 and 1.8, but some of the peculiar and bipolar nebulae fall below log R = 1.2. The corresponding N(C++)/N(Si++) ionic ratio varies over a large range. 53 references

  12. A detailed study of the structure of the nested planetary nebula, Hb 12, the Matryoshka nebula

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D. M.; López, J. A. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Campus Ensenada, Ensenada, Baja California, 22860 (Mexico); Edwards, M. L. [LBT Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Winge, C., E-mail: dmclark@astrosen.unam.mx, E-mail: jal@astrosen.unam.mx, E-mail: medwards@lbto.org, E-mail: cwinge@gemini.edu [Gemini Observatory, Southern Operations Center, c/o AURA Inc., Casilla 603, La Serena (Chile)

    2014-11-01

    We present near-IR, integral field spectroscopic observations of the planetary nebula (PN) Hb 12 using Near-infrared Integral Field Spectrograph (NIFS) on Gemini-North. Combining NIFS with the adaptive optics system Altair, we provide a detailed study of the core and inner structure of this PN. We focus the analysis in the prominent emission lines [Fe II] (1.6436 μm), He I (2.0585 μm), H{sub 2} (2.1214 μm), and Br{sub γ} (2.16553 μm). We find that the [Fe II] emission traces a tilted system of bipolar lobes, with the northern lobe being redshifted and the southern lobe blueshifted. The [Fe II] emission is very faint at the core and only present close to the systemic velocity. There is no H{sub 2} emission in the core, whereas the core is prominent in the He I and Br{sub γ} recombination lines. The H{sub 2} emission is concentrated in equatorial arcs of emission surrounding the core and expanding at ∼30 km s{sup –1}. These arcs are compared with Hubble Space Telescope images and shown to represent nested loops belonging to the inner sections of a much larger bipolar structure that replicates the inner one. The He I and Br{sub γ} emission from the core clearly show a cylindrical central cavity that seems to represent the inner walls of an equatorial density enhancement or torus. The torus is 0.''2 wide (≡200 AU radius at a distance of 2000 pc) and expanding at ≤30 km s{sup –1}. The eastern wall of the inner torus is consistently more intense than the western wall, which could indicate the presence of an off-center star, such as is observed in the similar hourglass PN, MyCn 18. A bipolar outflow is also detected in Br{sub γ} emerging within 0.''1 from the core at ∼ ± 40 km s{sup –1}.

  13. Formation of Bipolar Lobes by Jets

    Science.gov (United States)

    Soker, Noam

    2002-04-01

    I conduct an analytical study of the interaction of jets, or a collimated fast wind (CFW), with a previously blown asymptotic giant branch (AGB) slow wind. Such jets (or CFWs) are supposedly formed when a compact companion, a main-sequence star, or a white dwarf accretes mass from the AGB star, forms an accretion disk, and blows two jets. This type of flow, which I think shapes bipolar planetary nebulae (PNs), requires three-dimensional gasdynamical simulations, which are limited in the parameter space they can cover. By imposing several simplifying assumptions, I derive simple expressions which reproduce some basic properties of lobes in bipolar PNs and which can be used to guide future numerical simulations. I quantitatively apply the results to two proto-PNs. I show that the jet interaction with the slow wind can form lobes which are narrow close to, and far away from, the central binary system, and which are wider somewhere in between. Jets that are recollimated and have constant cross section can form cylindrical lobes with constant diameter, as observed in several bipolar PNs. Close to their source, jets blown by main-sequence companions are radiative; only further out they become adiabatic, i.e., they form high-temperature, low-density bubbles that inflate the lobes.

  14. THE VARIABLE REFLECTION NEBULA CEPHEUS A EAST

    International Nuclear Information System (INIS)

    Hodapp, Klaus W.; Bressert, Eli

    2009-01-01

    We report K'-band imaging observations of the reflection nebula associated with Cepheus A East covering the time interval from 1990 to 2004. Over this time the reflection nebula shows variations of flux distribution, which we interpret as the effect of inhomogeneous and varying extinction in the light path from the illuminating source HW2 to the reflection nebula. The obscuring material is located within typical distances of ∼ 10 AU from the illuminating source.

  15. PC 11: Symbiotic star or planetary nebulae?

    International Nuclear Information System (INIS)

    Gutierrez-Moreno, A.; Moreno, H.; Cortes, G.

    1987-01-01

    PC 11 is an object listed in Perek and Kohoutek (1967) Catalogue of Galactic Planetary Nebulae as PK 331 -5 0 1. Some authors suggest that it is not a planetary nebula, but that it has some characteristics (though not all) of symbiotic stars. We have made photographic, spectrophotometric and spectroscopic observations of PC 11. The analysis of the results suggests that it is a young planetary nebula. (Author)

  16. The western Veil nebula (Image)

    Science.gov (United States)

    Glenny, M.

    2009-12-01

    The western Veil nebula in Cygnus. 15-part mosaic by Mike Glenny, Gloucestershire, taken over several months mostly in the autumn of 2008. 200mm LX90/f10 autoguided, Meade UHC filter, 0.3xFR/FF, Canon 20Da DSLR. Exposures each typically 10x360 secs at ISO1600, processed in Registax4, PixInsight (for flat field correction) & Photoshop CS.

  17. Nutrition and Bipolar Depression.

    Science.gov (United States)

    Beyer, John L; Payne, Martha E

    2016-03-01

    As with physical conditions, bipolar disorder is likely to be impacted by diet and nutrition. Patients with bipolar disorder have been noted to have relatively unhealthy diets, which may in part be the reason they also have an elevated risk of metabolic syndrome and obesity. An improvement in the quality of the diet should improve a bipolar patient's overall health risk profile, but it may also improve their psychiatric outcomes. New insights into biological dysfunctions that may be present in bipolar disorder have presented new theoretic frameworks for understanding the relationship between diet and bipolar disorder. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Electron densities in planetary nebulae

    International Nuclear Information System (INIS)

    Stanghellini, L.; Kaler, J.B.

    1989-01-01

    Electron densities for 146 planetary nebulae have been obtained for analyzing a large sample of forbidden lines by interpolating theoretical curves obtained from solutions of the five-level atoms using up-to-date collision strengths and transition probabilities. Electron temperatures were derived from forbidden N II and/or forbidden O III lines or were estimated from the He II 4686 A line strengths. The forbidden O II densities are generally lower than those from forbidden Cl III by an average factor of 0.65. For data sets in which forbidden O II and forbidden S II were observed in common, the forbidden O II values drop to 0.84 that of the forbidden S II, implying that the outermost parts of the nebulae might have elevated densities. The forbidden Cl II and forbidden Ar IV densities show the best correlation, especially where they have been obtained from common data sets. The data give results within 30 percent of one another, assuming homogeneous nebulae. 106 refs

  19. Evolution of planetary nebula nuclei

    International Nuclear Information System (INIS)

    Shaw, R.A.

    1985-01-01

    The evolution of planetary nebula nuclei (PNNs) is examined with the aid of the most recent available stellar evolution calculations and new observations of these objects. Their expected distribution in the log L-log T plane is calculated based upon the stellar evolutionary models of Paczynski, Schoenberner and Iben, the initial mass function derived by Miller and Scalo, and various assumptions concerning mass loss during post-main sequence evolution. The distribution is found to be insensitive both to the assumed range of main-sequence progenitor mass and to reasonable variations in the age and the star forming history of the galactic disk. Rather, the distribution is determined by the strong dependence of the rate of stellar evolution upon core mass, the steepness of the initial mass function, and to a lesser extent the finite lifetime of an observable planetary nebula. The theoretical distributions are rather different than any of those inferred from earlier observations. Possible observational selection effects that may be responsible are examined, as well as the intrinsic uncertainties associated with the theoretical model predictions. An extensive photometric and smaller photographic survey of southern hemisphere planetary nebulae (PNs) is presented

  20. X-ray observations of planetary nebulae

    International Nuclear Information System (INIS)

    Apparao, K.M.V.; Tarafdar, S.P.

    1990-01-01

    The Einstein satellite was used to observe 19 planetary nebulae and X-ray emission was detected from four planetary nebulae. The EXOSAT satellite observed 12 planetary nebulae and five new sources were detected. An Einstein HRI observation shows that NGC 246 is a point source, implying that the X-rays are from the central star. Most of the detected planetary nebulae are old and the X-rays are observed during the later stage of planetary nebulae/central star evolution, when the nebula has dispersed sufficiently and/or when the central star gets old and the heavy elements in the atmosphere settle down due to gravitation. However in two cases where the central star is sufficiently luminous X-rays were observed, even though they were young nebulae; the X-radiation ionizes the nebula to a degree, to allow negligible absorption in the nebula. Temperature T x is obtained using X-ray flux and optical magnitude and assuming the spectrum is blackbody. T x agrees with Zanstra temperature obtained from optical Helium lines. (author)

  1. Medium-resolution échelle spectroscopy of the Red Square Nebula, MWC 922

    Science.gov (United States)

    Wehres, N.; Ochsendorf, B. B.; Tielens, A. G. G. M.; Cox, N. L. J.; Kaper, L.; Bally, J.; Snow, T. P.

    2017-05-01

    Context. Medium-resolution échelle spectra of the Red Square Nebula surrounding the star MWC 922 are presented. The spectra have been obtained in 2010 and 2012 using the X-shooter spectrograph mounted on the Very Large Telescope (VLT) in Paranal, Chile. The spectrum covers a wavelength range between 300 nm-2.5 μm and shows that the nebula is rich in emission lines. Aims: We aim to identify the emission lines and use them as a tool to determine the physical and chemical characteristics of the nebula. The emission lines are also used to put constraints on the structure of the nebula and on the nature of the central stars. Methods: We analyzed and identified emission lines that indicated that the Red Square Nebula consists of a low density bipolar outflow, eminent in the broad emission component seen in [Fe II], as well as in P Cygni line profiles indicative of fast outflowing material. The narrow component in the [Fe II] lines is most likely formed in the photosphere of a surrounding disk. Some of the emission lines show a pronounced double peaked profile, such as Ca II, indicating an accretion disk in Keplerian rotation around the central star. [O I] emission lines are formed in the neutral atomic zone separating the ionized disk photosphere from the molecular gas in the interior of the disk, which is prominent in molecular CO emission in the near-IR. [N II] and [S II] emission clearly originates in a low density but fairly hot (7 000-10 000 K) nebular environment. H I recombination lines trace the extended nebula as well as the photosphere of the disk. Results: These findings put constraints on the evolution of the central objects in MWC 922. The Red Square shows strong similarities to the Red Rectangle Nebula, both in morphology and in its mid-IR spectroscopic characteristics. As for the Red Rectangle, the observed morphology of the nebula reflects mass-loss in a binary system. Specifically, we attribute the biconical morphology and the associated rung

  2. Bipolar soft connected, bipolar soft disconnected and bipolar soft compact spaces

    Directory of Open Access Journals (Sweden)

    Muhammad Shabir

    2017-06-01

    Full Text Available Bipolar soft topological spaces are mathematical expressions to estimate interpretation of data frameworks. Bipolar soft theory considers the core features of data granules. Bipolarity is important to distinguish between positive information which is guaranteed to be possible and negative information which is forbidden or surely false. Connectedness and compactness are the most important fundamental topological properties. These properties highlight the main features of topological spaces and distinguish one topology from another. Taking this into account, we explore the bipolar soft connectedness, bipolar soft disconnectedness and bipolar soft compactness properties for bipolar soft topological spaces. Moreover, we introduce the notion of bipolar soft disjoint sets, bipolar soft separation, and bipolar soft hereditary property and study on bipolar soft connected and disconnected spaces. By giving the detailed picture of bipolar soft connected and disconnected spaces we investigate bipolar soft compact spaces and derive some results related to this concept.

  3. Luminosity function for planetary nebulae and the number of planetary nebulae in local group galaxies

    International Nuclear Information System (INIS)

    Jacoby, G.H.

    1980-01-01

    Identifications of 19 and 34 faint planetary nebulae have been made in the central regions of the SMC and LMC, respectively, using on-line/off-line filter photography at [O III] and Hα. The previously known brighter planetary nebulae in these fields, eight in both the SMC and the LMC, were also identified. On the basis of the ratio of the numbers of faint to bright planetary nebulae in these fields and the numbers of bright planetary nebulae in the surrounding fields, the total numbers of planetary nebulae in the SMC and LMC are estimated to be 285 +- 78 and 996 +- 253, respectively. Corrections have been applied to account for omissions due to crowding confusion in previous surveys, spatial and detectability incompleteness, and obscuration by dust.Equatorial coordinates and finding charts are presented for all the identified planetary nebulae. The coordinates have uncertainties smaller than 0.''6 relative to nearby bright stars, thereby allowing acquisition of the planetary nebulae by bling offsetting.Monochromatic fluxes are derived photographically and used to determine the luminosity function for Magellanic Cloud planetary nebulae as faint as 6 mag below the brightest. The luminosity function is used to estimate the total numbers of planetary nebulae in eight Local Group galaxies in which only bright planetary nebulae have been identified. The dervied luminosity specific number of planetary nebulae per unit luminosity is nearly constant for all eight galaxies, having a value of 6.1 x 10 -7 planetary nebulae L -1 /sub sun/. The mass specific number, based on the three galaxies with well-determined masses, is 2.1 x 10 -7 planetary nebulae M -1 /sub sun/. With estimates for the luminosity and mass of our Galaxy, its total number of planetary nebulae is calculated to be 10,000 +- 4000, in support of the Cudworth distance scale

  4. Optical observations of southern planetary nebula candidates

    NARCIS (Netherlands)

    VandeSteene, GC; Sahu, KC; Pottasch, [No Value

    1996-01-01

    We present H alpha+[NII] images and low resolution spectra of 16 IRAS-selected, southern planetary nebula candidates previously detected in the radio continuum. The H alpha+[NII] images are presented as finding charts. Contour plots are shown for the resolved planetary nebulae. From these images

  5. Abundances of planetary nebula NGC 5315

    NARCIS (Netherlands)

    Pottasch, [No Value; Beintema, DA; Salas, JB; Koornneef, J; Feibelman, WA

    2002-01-01

    The ISO and IUE spectra of the elliptical nebula NGC 5315 is presented. These spectra are combined with the spectra in the visual wavelength region to obtain a complete, extinction corrected, spectrum. The chemical composition of the nebulae is then calculated and compared to previous

  6. Plerions and pulsar-powered nebulae

    OpenAIRE

    Gaensler, Bryan

    2000-01-01

    In this brief review, I discuss recent developments in the study of pulsar-powered nebulae ("plerions"). The large volume of data which has been acquired in recent years reveals a diverse range of observational properties, demonstrating how differing environmental and pulsar properties manifest themselves in the resulting nebulae.

  7. A Smoking Gun in the Carina Nebula

    Science.gov (United States)

    Hamaguchi, Kenji; Corcoran, Michael F.; Ezoe, Yuichiro; Townsley, Leisa; Broos, Patrick; Gruendl, Robert; Vaidya, Kaushar; White, Stephen M.; Petre, Rob; Chu, You-Hua

    2009-01-01

    The Carina Nebula is one of thc youngest, most active sites of massive star formation in our Galaxy. In this nebula, we have discovered a bright X-ray source that has persisted for approx.30 years. The soft X-ray spectrum. consistent with kT approx.130 eV blackbody radiation with mild extinction, and no counterpart in the near- and mid-infrared wavelengths indicate that it is a, approx. 10(exp 6)-year-old neutron star housed in the Carina Nebula. Current star formation theory does not suggest that the progenitor of the neutron star and massive stars in the Carina Nebula, in particular (eta)Car, are coeval. This result demonstrates that the Carina Nebula experienced at least two major episodes of massive star formation. The neutron star would be responsible for remnants of high energy activity seen in multiple wavelengths.

  8. A SMOKING GUN IN THE CARINA NEBULA

    International Nuclear Information System (INIS)

    Hamaguchi, Kenji; Corcoran, Michael F.; Ezoe, Yuichiro; Townsley, Leisa; Broos, Patrick; Gruendl, Robert; Vaidya, Kaushar; Chu, You-Hua; White, Stephen M.; Strohmayer, Tod; Petre, Rob

    2009-01-01

    The Carina Nebula is one of the youngest, most active sites of massive star formation in our Galaxy. In this nebula, we have discovered a bright X-ray source that has persisted for ∼30 years. The soft X-ray spectrum, consistent with kT ∼ 128 eV blackbody radiation with mild extinction, and no counterpart in the near- and mid-infrared wavelengths indicates that it is a ∼10 6 year old neutron star housed in the Carina Nebula. Current star formation theory does not suggest that the progenitors of the neutron star and massive stars in the Carina Nebula, in particular η Car, are coeval. This result suggests that the Carina Nebula experienced at least two major episodes of massive star formation. The neutron star may be responsible for remnants of high-energy activity seen in multiple wavelengths.

  9. Genetics Home Reference: bipolar disorder

    Science.gov (United States)

    ... Email Facebook Twitter Home Health Conditions Bipolar disorder Bipolar disorder Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Bipolar disorder is a mental health condition that causes extreme ...

  10. BIPOLAR DISORDER: A REVIEW

    OpenAIRE

    Pathan Dilnawaz N; Ziyaurrahaman A.R; Bhise K.S.

    2010-01-01

    Bipolar disorder (BD) is a severe psychiatric disorder that results in poor global functioning, reduced quality of life and high relapse rates. Research finds that many adults with bipolar disorder identify the onset of symptoms in childhood and adolescence, indicating the importance of early accurate diagnosis and treatment. Accurate diagnosis of mood disorders is critical for treatment to be effective. Distinguishing between major depression and bipolar disorders, especially the depressed p...

  11. Bipolar Disorder in Women

    Directory of Open Access Journals (Sweden)

    Sermin Kesebir

    2013-06-01

    Full Text Available The research on gender's role in bipolar disorders has drawn significant interest recently. The presentation and course of bipolar disorder differs between women and men. Women experience depressive episodes, dysphoric mood, mixed states, rapid cycling and seasonal patterns more often than men. Comorbidity, particularly thyroid disease, migraine, obesity, and anxiety disorders laso occur more frequently in women than men. On the other hand men with bipolar disorder are also more likely than women to have problems with drug or alcohol abuse. The pregnancy and postpartum period is a time of high risk for onset and recurrence of bipolar disorder in women.

  12. Proto-Planetary Disk Chemistry Recorded by D-Rich Organic Radicals in Carbonaceous Chondrites

    OpenAIRE

    Remusat, Laurent; Robert, François; Meibom, Anders; Mostefaoui, Smail; Delpoux, Olivier; Binet, Laurent; Gourier, Didier; Derenne, Sylvie

    2009-01-01

    Insoluble organic matter (IOM) in primitive carbonaceous meteorites has preserved its chemical composition and isotopic heterogeneity since the solar system formed ~4.567 billion years ago. We have identified the carrier moieties of isotopically anomalous hydrogen in IOM isolated from the Orgueil carbonaceous chondrite. Data from high spatial resolution, quantitative isotopic NanoSIMS mapping of Orgueil IOM combined with data from electron paramagnetic resonance spectroscopy reveals that orga...

  13. SHORT DISSIPATION TIMES OF PROTO-PLANETARY DISKS: AN ARTIFACT OF SELECTION EFFECTS?

    International Nuclear Information System (INIS)

    Pfalzner, Susanne; Steinhausen, Manuel; Menten, Karl

    2014-01-01

    The frequency of disks around young stars, a key parameter for understanding planet formation, is most readily determined in young stellar clusters where many relatively coeval stars are located in close proximity. Observational studies seem to show that the disk frequency decreases rapidly with cluster age with <10% of cluster stars retaining their disks for longer than 2-6 Myr. Given that at least half of all stars in the field seem to harbor one or more planets, this would imply extremely fast disk dispersal and rapid planet growth. Here we question the validity of this constraint by demonstrating that the short disk dissipation times inferred to date might have been heavily underestimated by selection effects. Critically, for ages >3 Myr only stars that originally populated the densest areas of very populous clusters, which are prone to disk erosion, are actually considered. This tiny sample may not be representative of the majority of stars. In fact, the higher disk fractions in co-moving groups indicate that it is likely that over 30% of all field stars retain their disks well beyond 10 Myr, leaving ample time for planet growth. Equally, our solar system, with a likely formation time >10 Myr, need no longer be an exception but in fact typical of planetary systems

  14. Planet gaps in the dust layer of 3D proto-planetary disks: Observability with ALMA

    OpenAIRE

    Gonzalez, Jean-François; Pinte, Christophe; Maddison, Sarah T.; Ménard, François

    2013-01-01

    2 pages, 2 figures, to appear in the Proceedings of IAU Symp. 299: Exploring the Formation and Evolution of Planetary Systems (Victoria, Canada); International audience; Among the numerous known extrasolar planets, only a handful have been imaged directly so far, at large orbital radii and in rather evolved systems. The Atacama Large Millimeter/submillimeter Array (ALMA) will have the capacity to observe these wide planetary systems at a younger age, thus bringing a better understanding of th...

  15. NIF Discovery Science Eagle Nebula

    Science.gov (United States)

    Kane, Jave; Martinez, David; Pound, Marc; Heeter, Robert; Casner, Alexis; Villette, Bruno; Mancini, Roberto

    2017-10-01

    The University of Maryland and and LLNL are investigating the origin and dynamics of the famous Pillars of the Eagle Nebula and similar parsec-scale structures at the boundaries of HII regions in molecular hydrogen clouds. The National Ignition Facility (NIF) Discovery Science program Eagle Nebula has performed NIF shots to study models of pillar formation. The shots feature a new long-duration x-ray source, in which multiple hohlraums mimicking a cluster of stars are driven with UV light in series for 10 to 15 ns each to create a 30 to 60 ns output x-ray pulse. The source generates deeply nonlinear hydrodynamics in the Eagle science package, a structure of dense plastic and foam mocking up a molecular cloud containing a dense core. Omega EP and NIF shots have validated the source concept, showing that earlier hohlraums do not compromise later ones by preheat or by ejecting ablated plumes that deflect later beams. The NIF shots generated radiographs of shadowing-model pillars, and also showed evidence that cometary structures can be generated. The velocity and column density profiles of the NIF shadowing and cometary pillars have been compared with observations of the Eagle Pillars made at the millimeter-wave BIMA and CARMA observatories. Prepared by LLNL under Contract DE-AC52-07NA27344.

  16. A DETAILED MORPHO-KINEMATIC MODEL OF THE ESKIMO, NGC 2392: A UNIFYING VIEW WITH THE CAT'S EYE AND SATURN PLANETARY NEBULAE

    International Nuclear Information System (INIS)

    García-Díaz, Ma. T.; López, J. A.; Steffen, W.; Richer, M. G.

    2012-01-01

    The three-dimensional and kinematic structure of the Eskimo nebula, NGC 2392, has been notoriously difficult to interpret in detail given its complex morphology, multiple kinematic components and its nearly pole-on orientation along the line of sight. We present a comprehensive, spatially resolved, high-resolution, long-slit spectroscopic mapping of the Eskimo planetary nebula. The data consist of 21 spatially resolved, long-slit echelle spectra tightly spaced over the Eskimo and along its bipolar jets. This data set allows us to construct a velocity-resolved [N II] channel map of the nebula with a resolution of 10 km s –1 that disentangles its different kinematic components. The spectroscopic information is combined with Hubble Space Telescope images to construct a detailed three-dimensional morpho-kinematic model of the Eskimo using the code SHAPE. With this model we demonstrate that the Eskimo is a close analog to the Saturn and the Cat's Eye nebulae, but rotated 90° to the line of sight. Furthermore, we show that the main characteristics of our model apply to the general properties of the group of elliptical planetary nebulae with ansae or FLIERS, once the orientation is considered. We conclude that this kind of nebula belongs to a class with a complex common evolutionary sequence of events.

  17. Reconstruction and visualization of planetary nebulae.

    Science.gov (United States)

    Magnor, Marcus; Kindlmann, Gordon; Hansen, Charles; Duric, Neb

    2005-01-01

    From our terrestrially confined viewpoint, the actual three-dimensional shape of distant astronomical objects is, in general, very challenging to determine. For one class of astronomical objects, however, spatial structure can be recovered from conventional 2D images alone. So-called planetary nebulae (PNe) exhibit pronounced symmetry characteristics that come about due to fundamental physical processes. Making use of this symmetry constraint, we present a technique to automatically recover the axisymmetric structure of many planetary nebulae from photographs. With GPU-based volume rendering driving a nonlinear optimization, we estimate the nebula's local emission density as a function of its radial and axial coordinates and we recover the orientation of the nebula relative to Earth. The optimization refines the nebula model and its orientation by minimizing the differences between the rendered image and the original astronomical image. The resulting model allows creating realistic 3D visualizations of these nebulae, for example, for planetarium shows and other educational purposes. In addition, the recovered spatial distribution of the emissive gas can help astrophysicists gain deeper insight into the formation processes of planetary nebulae.

  18. Processing NASA Earth Science Data on Nebula Cloud

    Science.gov (United States)

    Chen, Aijun; Pham, Long; Kempler, Steven

    2012-01-01

    Three applications were successfully migrated to Nebula, including S4PM, AIRS L1/L2 algorithms, and Giovanni MAPSS. Nebula has some advantages compared with local machines (e.g. performance, cost, scalability, bundling, etc.). Nebula still faces some challenges (e.g. stability, object storage, networking, etc.). Migrating applications to Nebula is feasible but time consuming. Lessons learned from our Nebula experience will benefit future Cloud Computing efforts at GES DISC.

  19. Planetary nebulae and the interstellar magnetic field

    International Nuclear Information System (INIS)

    Heiligman, G.M.

    1980-01-01

    Previous workers have found a statistical correlation between the projected directions of the interstellar magnetic field and the major axes of planetary nebulae. This result has been examined theoretically using a numerical hydromagnetic model of a cold plasma nebula expanding into a uniform vacuum magnetic field, with nebular gas accreting on the surface. It is found that magnetic pressure alone is probably not sufficient to shape most planetary nebulae to the observed degree. Phenomena are discussed which could amplify simple magnetic pressure, alter nebular morphology and account for the observed correlation. (author)

  20. Spatiokinematical models of five planetary nebulae

    International Nuclear Information System (INIS)

    Sabbadin, F.

    1984-01-01

    The [OOOI] and Hα expansion velocity fields in the planetary nebulae NGC6058 and 6804 and the [OIII], Hα and [NII] expansion velocity fields in NGC6309, 6751 and 6818, were obtained from high dispersion spectra. Spatiokinematical models of the nebulae were derived assuming an expansion velocity of the gas proportional to the distance from the central star and using the expansion velocity-radius correlation previously given. The observational parameters of the nebulae (radius, mass and expansion velocity) and of the exciting stars (temperature, radius and luminosity) closely fit the suggested evolutionary model for this class of objects. (author)

  1. Comparative familial aggregation of bipolar disorder in patients with bipolar I and bipolar II disorders.

    Science.gov (United States)

    Parker, Gordon B; Romano, Mia; Graham, Rebecca K; Ricciardi, Tahlia

    2018-05-01

    We sought to quantify the prevalence and differential prevalence of a bipolar disorder among family members of patients with a bipolar I or II disorder. The sample comprised 1165 bipolar and 1041 unipolar patients, with the former then sub-typed as having either a bipolar I or II condition. Family history data was obtained via an online self-report tool. Prevalence of a family member having a bipolar disorder (of either sub-type) was distinctive (36.8%). Patients with a bipolar I disorder reported a slightly higher family history (41.2%) compared to patients with a bipolar II disorder (36.3%), and with both significantly higher than the rate of bipolar disorder in family members of unipolar depressed patients (18.5%). Findings support the view that bipolar disorder is heritable. The comparable rates in the two bipolar sub-types support the positioning of bipolar II disorder as a valid condition with strong genetic underpinnings.

  2. Properties of Bipolar Fuzzy Hypergraphs

    OpenAIRE

    Akram, M.; Dudek, W. A.; Sarwar, S.

    2013-01-01

    In this article, we apply the concept of bipolar fuzzy sets to hypergraphs and investigate some properties of bipolar fuzzy hypergraphs. We introduce the notion of $A-$ tempered bipolar fuzzy hypergraphs and present some of their properties. We also present application examples of bipolar fuzzy hypergraphs.

  3. FAST, LOW-IONIZATION EMISSION REGIONS OF THE PLANETARY NEBULA M2-42

    Energy Technology Data Exchange (ETDEWEB)

    Danehkar, A.; Parker, Q. A. [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia); Steffen, W., E-mail: ashkbiz.danehkar@cfa.harvard.edu [Instituto de Astronomía, Universidad Nacional Autónoma de México, C.P.22860, Ensenada (Mexico)

    2016-02-15

    Spatially resolved observations of the planetary nebula M2-42 (PN G008.2−04.8) obtained with the Wide Field Spectrograph on the Australian National University 2.3 m telescope have revealed the remarkable features of bipolar collimated jets emerging from its main structure. Velocity-resolved channel maps derived from the [N ii] λ6584 emission line disentangle different morphological components of the nebula. This information is used to develop a three-dimensional morpho-kinematic model, which consists of an equatorial dense torus and a pair of asymmetric bipolar outflows. The expansion velocity of about 20 km s{sup −1} is measured from the spectrum integrated over the main shell. However, the deprojected velocities of the jets are found to be in the range of 80–160 km s{sup −1} with respect to the nebular center. It is found that the mean density of the collimated outflows, 595 ± 125 cm{sup −3}, is five times lower than that of the main shell, 3150 cm{sup −3}, whereas their singly ionized nitrogen and sulfur abundances are about three times higher than those determined from the dense shell. The results indicate that the features of the collimated jets are typical of fast, low-ionization emission regions.

  4. Nebulae and how to observe them

    CERN Document Server

    Coe, Steven

    2007-01-01

    This "Astronomers' Observing Guides" are designed for practical amateur astronomers who not only want to observe, but want to know the details of exactly what they are looking at. Nebulae are the places where the stars are born. For amateur astronomers, the many different kinds of nebulae vary from "easy" targets that can be seen with modest equipment under mediocre skies, to "challenging" objects that require experienced observers, large telescopes and excellent seeing. The concept of the book - and of the series - is to present an up-to-date detailed description and categorisation (part one); and then (part two) to consider how best to successfully observe and record the large range of astronomical objects that fall under the general heading of "nebulae". "Nebulae, and How to Observe Them" is a mine of information for all levels of amateur observers, from the beginner to the experienced.

  5. Hot relativistic winds and the Crab nebula

    International Nuclear Information System (INIS)

    Fujimura, F.S.; Kennel, C.F.

    1981-01-01

    Efforts are reviewed to construct a self-consistent model of pulsar magnetospheres that links the particle source near the pulsar to the outflowing relativistic wind and couples the wind to the surrounding nebula. (Auth.)

  6. Is gas in the Orion nebula depleted

    International Nuclear Information System (INIS)

    Aiello, S.; Guidi, I.

    1978-01-01

    Depletion of heavy elements has been recognized to be important in the understanding of the chemical composition of the interstellar medium. This problem is also relevant to the study of H II regions. In this paper the gaseous depletion in the physical conditions of the Orion nebula is investigated. The authors reach the conclusion that very probably no depletion of heavy elements, due to sticking on dust grains, took place during the lifetime of the Orion nebula. (Auth.)

  7. Bipolar Disorder in Children

    Science.gov (United States)

    2014-01-01

    Although bipolar disorder historically was thought to only occur rarely in children and adolescents, there has been a significant increase in children and adolescents who are receiving this diagnosis more recently (Carlson, 2005). Nonetheless, the applicability of the current bipolar disorder diagnostic criteria for children, particularly preschool children, remains unclear, even though much work has been focused on this area. As a result, more work needs to be done to further the understanding of bipolar symptoms in children. It is hoped that this paper can assist psychologists and other health service providers in gleaning a snapshot of the literature in this area so that they can gain an understanding of the diagnostic criteria and other behaviors that may be relevant and be informed about potential approaches for assessment and treatment with children who meet bipolar disorder criteria. First, the history of bipolar symptoms and current diagnostic criteria will be discussed. Next, assessment strategies that may prove helpful for identifying bipolar disorder will be discussed. Then, treatments that may have relevance to children and their families will be discussed. Finally, conclusions regarding work with children who may have a bipolar disorder diagnosis will be offered. PMID:24800202

  8. Evolutionary sequence of models of planetary nebulae

    International Nuclear Information System (INIS)

    Vil'koviskij, Eh.Ya.; Kondrat'eva, L.N.; Tambovtseva, L.V.

    1983-01-01

    The evolutionary sequences of model planetary nebulae of different masses have been calculated. The computed emission line intensities are compared with the observed ones by means of the parameter ''reduced size of the nebula'', Rsub(n). It is shown that the evolution tracks of Schonberner for the central stars are consistent with the observed data. Part of ionized mass Mi in any nebulae does not not exceed 0.3 b and in the average Msu(i) 3 years at actual values of radius Rsub(i) <0.025 ps. Then the luminosity growth slows down to the maximum temperature which central star reaches and decreases with sharp decrease of the star luminosity. At that, the radius of ionized zone of greater mass nebulae can even decrease, inspite of the constant expansion of the nebula. As a result nebulae of great masses having undergone the evolution can be included in the number of observed compact objects (Rsub(n) < 0.1 ps)

  9. Photoionization modelling of planetary nebulae - II. Galactic bulge nebulae, a comparison with literature results

    NARCIS (Netherlands)

    van Hoof, PAM; Van de Steene, GC

    1999-01-01

    We have constructed photoionization models of five galactic bulge planetary nebulae using our automatic method, which enables a fully self-consistent determination of the physical parameters of a planetary nebula. The models are constrained using the spectrum, the IRAS and radio fluxes and the

  10. High-resolution 8-13 micron imaging of the planetary nebulae BD + 30 deg 3639 and NGC 6572

    International Nuclear Information System (INIS)

    Hora, J.L.; Hoffmann, W.F.; Deutsch, L.K.; Fazio, G.G.

    1990-01-01

    High-resolution midinfrared images of the planetary nebulae BD + 30 deg 3639 and NGC 6572 are presented at 8.3, 8.7, 9.8, 11.2, and 12.4 microns. Analysis of the maps of BD + 30 deg 3639 supports a model in which the infrared emission originates from two spatially distinct components, one which is responsible for the continuum radiation at 8-12 microns and the other which produces the emission-line features. The NGC 6572 images provides evidence for a previously undetected 11.2 micron UIR emission feature. Comparison with radio continuum maps indicates that the distribution of dust is similar to the distribution of ionized gas in each nebula. Various models of source morphology are also investigated. The planetary nebulae DB + 30 deg 3639 and NGC 6572 can be modeled by an optically thin cylinder or a prolate ellipsoid with enhanced equatorial emission. These models reproduce well the general features of the nebula, such as the bipolar lobes of emission and the ring structure. 67 refs

  11. What is Bipolar Disorder?

    Science.gov (United States)

    ... down” Have trouble sleeping Think about death or suicide Can someone have bipolar disorder along with other problems? Yes. Sometimes people having very strong mood episodes may have psychotic symptoms. Psychosis affects thoughts ...

  12. The Crab Nebula flaring activity

    Energy Technology Data Exchange (ETDEWEB)

    Montani, G., E-mail: giovanni.montani@frascati.enea.it [ENEA – C.R, UTFUS-MAG, via Enrico Fermi 45, I-00044 Frascati (RM) (Italy); Dipartimento di Fisica, Università di Roma “Sapienza”, p.le Aldo Moro 5, I-00185 Roma (Italy); Bernardini, M.G. [INAF – Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (Italy)

    2014-12-12

    The discovery made by AGILE and Fermi of a short time scale flaring activity in the gamma-ray energy emission of the Crab Nebula is a puzzling and unexpected feature, challenging particle acceleration theory. In the present work we propose the shock-induced magnetic reconnection as a viable mechanism to explain the Crab flares. We postulate that the emitting region is located at ∼10{sup 15} cm from the central pulsar, well inside the termination shock, which is exactly the emitting region size as estimated by the overall duration of the phenomenon ∼1 day. We find that this location corresponds to the radial distance at which the shock-induced magnetic reconnection process is able to accelerate the electrons up to a Lorentz factor ∼10{sup 9}, as required by the spectral fit of the observed Crab flare spectrum. The main merit of the present analysis is to highlight the relation between the observational constraints to the flare emission and the radius at which the reconnection can trigger the required Lorentz factor. We also discuss different scenarios that can induce the reconnection. We conclude that the existence of a plasma instability affecting the wind itself as the Weibel instability is the privileged scenario in our framework.

  13. Mass Transfer in Mira-Type Binaries

    Directory of Open Access Journals (Sweden)

    Mohamed S.

    2012-06-01

    Full Text Available Detached, symbiotic binaries are generally assumed to interact via Bondi-Hoyle-Littleton (BHL wind accretion. However, the accretion rates and outflow geometries that result from this mass-transfer mechanism cannot adequately explain the observations of the nearest and best studied symbiotic binary, Mira, or the formation of some post-AGB binaries, e.g. barium stars. We propose a new mass-transfer mode for Mira-type binaries, which we call ‘wind Roche-lobe overflow’ (WRLOF, and which we demonstrate with 3D hydrodynamic simulations. Importantly, we show that the circumstellar outflows which result from WRLOF tend to be highly aspherical and strongly focused towards the binary orbital plane. Furthermore, the subsequent mass-transfer rates are at least an order of magnitude greater than the analogous BHL values. We discuss the implications of these results for the shaping of bipolar (proto-planetary nebulae and other related systems.

  14. Abundance determinations in HII regions and planetary nebulae

    OpenAIRE

    Stasinska, Grazyna

    2002-01-01

    The methods of abundance determinations in HII regions and planetary nebulae are described, with emphasis on the underlying assumptions and inherent problems. Recent results on abundances in Galactic HII regions and in Galactic and extragalactic Planetary Nebulae are reviewed.

  15. The simplest models of the reflection nebulae

    International Nuclear Information System (INIS)

    Voshchinnikov, N.V.

    1977-01-01

    Some models of the reflection nebulue have been considered. The (U-B), (B-V) and (V-R) colors and the U, B, V and R polarization have been calculated for a model of a reflection nebula associated with a large dust cloud. For the cases in which the illuminating star is far from the surface of the cloud, the form of the nebula has been considered to be spherical. If the star is close to the surface of the cloud, a part of the nebura boundary has been considered to be flat. Single scattering within the homogeneous nebula has been assumed. All the calculations use the scattering by spheres as given by the Mie's theory. The effect of variations of chemical composition and size distribution function of the grains and the position of the illuminating star has been examined. Comparison of the theoretical results with the observations of the Merope nebula shows that the dirty ice grains with the refraction index m=1.30-0.02i and size parameter asub(o)=0.5μ represent satisfactorily the observation if the star is embedded 0.7 pc behind the front surface of the nebula

  16. Properties of interstellar dust in reflection nebulae

    International Nuclear Information System (INIS)

    Sellgren, K.

    1988-01-01

    Observations of interstellar dust in reflection nebulae are the closest analog in the interstellar medium to studies of cometary dust in our solar system. The presence of a bright star near the reflection nebula dust provides the opportunity to study both the reflection and emission characteristics of interstellar dust. At 0.1 to 1 micrometer, the reflection nebula emission is due to starlight scattered by dust. The albedo and scattering phase function of the dust is determined from observations of the scattered light. At 50 to 200 micrometers, thermal emission from the dust in equilibrium with the stellar radiation field is observed. The derived dust temperature determines the relative values of the absorption coefficient of the dust at wavelengths where the stellar energy is absorbed and at far infrared wavelengths where the absorbed energy is reradiated. These emission mechanisms directly relate to those seen in the near and mid infrared spectra of comets. In a reflection nebula the dust is observed at much larger distances from the star than in our solar system, so that the equilibrium dust temperature is 50 K rather than 300 K. Thus, in reflection nebulae, thermal emission from dust is emitted at 50 to 200 micrometer

  17. Lunar occultation observations of the Crab Nebula

    International Nuclear Information System (INIS)

    Maloney, F.P.

    1977-01-01

    Three lunar of occultations of the Crab Nebula were observed, two at 114 MHz and one at 26.3 MHz, during the 1974 series of events. The higher frequency observations were deconvolved of diffraction effects to yield four strip integrated brightness profiles of the Nebula, with an effective resolution of 30 arc-seconds. These four profiles were Fourier inverted and cleaned of sidelobe structure to synthesize a two-dimensional map of the Nebula. At 114 MHz, the Nebula is composed of a broad envelope of emission which contains several smaller sources. The attenuation of the low radio frequency radiation by the thermal hydrogen in the filaments is considered as a possible mechanism to explain these new data. The 26.3 MHz observations indicate the presence of a bright, localized source containing greater than 80% of the flux of the Nebula. The position of the source is confined by the data to a narrow strip centered at the pulsar position. Both sets of data are compared with past occultation observations

  18. Ring nebulae associated with Wolf-Rayet stars

    International Nuclear Information System (INIS)

    Chu, Y.-H.

    1982-01-01

    Using strict selection criteria, the author and colleagues have searched for ring nebulae associated with Wolf-Rayet stars in the Galaxy and the Magellanic Clouds. 15 WR ring nebulae are identified in the Galaxy, 9 in the Large Magellanic Cloud, and none in the small Magellanic Cloud. The morphology and kinematics of these 24 nebulae have subsequently been observed to study their nature. These nebulae and their references are listed and a correlation between spectral and nebular types is presented. (Auth.)

  19. Modelling the structure and kinematics of the Firework nebula: The nature of the GK Persei nova shell and its jet-like feature

    Science.gov (United States)

    Harvey, E.; Redman, M. P.; Boumis, P.; Akras, S.

    2016-10-01

    Aims: The shaping mechanisms of old nova remnants are probes for several important and unexplained processes, such as dust formation and the structure of evolved star nebulae. To gain a more complete understanding of the dynamics of the GK Per (1901) remnant, an examination of symmetry of the nova shell is explored, followed by a kinematical analysis of the previously detected jet-like feature in the context of the surrounding fossil planetary nebula. Methods: Faint-object high-resolution echelle spectroscopic observations and imaging were undertaken covering the knots which comprise the nova shell and the surrounding nebulosity. New imaging from the Aristarchos telescope in Greece and long-slit spectra from the Manchester Echelle Spectrometer instrument at the San Pedro Mártir observatory in Mexico were obtained, supplemented with archival observations from several other optical telescopes. Position-velocity arrays are produced of the shell, and also individual knots, and are then used for morpho-kinematic modelling with the shape code. The overall structure of the old knotty nova shell of GK Per and the planetary nebula in which it is embedded is then analysed. Results: Evidence is found for the interaction of knots with each other and with a wind component, most likely the periodic fast wind emanating from the central binary system. We find that a cylindrical shell with a lower velocity polar structure gives the best model fit to the spectroscopy and imaging. We show in this work that the previously seen jet-like feature is of low velocity. Conclusions: The individual knots have irregular tail shapes; we propose here that they emanate from episodic winds from ongoing dwarf nova outbursts by the central system. The nova shell is cylindrical, not spherical, and the symmetry axis relates to the inclination of the central binary system. Furthermore, the cylinder axis is aligned with the long axis of the bipolar planetary nebula in which it is embedded. Thus, the

  20. Monitoring the Crab Nebula with LOFT

    Science.gov (United States)

    Wilson-Hodge, Colleen A.

    2012-01-01

    From 2008-2010, the Crab Nebula was found to decline by 7% in the 15-50 keV band, consistently in Fermi GBM, INTEGRAL IBIS, SPI, and JEMX, RXTE PCA, and Swift BAT. From 2001-2010, the 15-50 keV flux from the Crab Nebula typically varied by about 3.5% per year. Analysis of RXTE PCA data suggests possible spectral variations correlated with the flux variations. I will present estimates of the LOFT sensitivity to these variations. Prior to 2001 and since 2010, the observed flux variations have been much smaller. Monitoring the Crab with the LOFT WFM and LAD will provide precise measurements of flux variations in the Crab Nebula if it undergoes a similarly active episode.

  1. Infrared reflection nebulae in Orion Molecular Cloud

    International Nuclear Information System (INIS)

    Pendleton, Y.; Werner, M.W.; Capps, R.; Lester, D.; Hawaii Univ., Honolulu; Texas Univ., Austin)

    1986-01-01

    New observations of Orion Molecular Cloud 2 have been made from 1 to 100 microns using the NASA Infrared Telescope Facility and the Kuiper Airborne Observatory. An extensive program of polarimetry, photometry, and spectrophotometry has shown that the extended emission regions associated with two of the previously known near-infrared sources, IRS 1 and IRS 4, are infrared reflection nebulae, and that the compact sources IRS 1 and IRS 4 are the main luminosity sources in the cloud. The constraints from the far-infrared observations and an analysis of the scattered light from the IRS 1 nebula show that OMC-2/IRS 1 can be characterized by L of 500 solar luminosities or less and T of roughly 1000 K. The near-infrared albedo of the grains in the IRS 1 nebula is greater than 0.08. 27 references

  2. Bipolar Affective Disorder and Migraine

    Directory of Open Access Journals (Sweden)

    Birk Engmann

    2012-01-01

    Full Text Available This paper consists of a case history and an overview of the relationship, aetiology, and treatment of comorbid bipolar disorder migraine patients. A MEDLINE literature search was used. Terms for the search were bipolar disorder bipolar depression, mania, migraine, mood stabilizer. Bipolar disorder and migraine cooccur at a relatively high rate. Bipolar II patients seem to have a higher risk of comorbid migraine than bipolar I patients have. The literature on the common roots of migraine and bipolar disorder, including both genetic and neuropathological approaches, is broadly discussed. Moreover, bipolar disorder and migraine are often combined with a variety of other affective disorders, and, furthermore, behavioural factors also play a role in the origin and course of the diseases. Approach to treatment options is also difficult. Several papers point out possible remedies, for example, valproate, topiramate, which acts on both diseases, but no first-choice treatments have been agreed upon yet.

  3. Depression and Bipolar Support Alliance

    Science.gov (United States)

    Depression and Bipolar Support Alliance Crisis Hotline Information Coping with a Crisis Suicide Prevention Information Psychiatric Hospitalization ... sign-up Education info, training, events Mood Disorders Depression Bipolar Disorder Anxiety Screening Center Co-occurring Illnesses/ ...

  4. Hubble Space Telescope Image of Omega Nebula

    Science.gov (United States)

    2002-01-01

    This sturning image, taken by the newly installed Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope (HST), is an image of the center of the Omega Nebula. It is a hotbed of newly born stars wrapped in colorful blankets of glowing gas and cradled in an enormous cold, dark hydrogen cloud. The region of nebula shown in this photograph is about 3,500 times wider than our solar system. The nebula, also called M17 and the Swan Nebula, resides 5,500 light-years away in the constellation Sagittarius. The Swan Nebula is illuminated by ultraviolet radiation from young, massive stars, located just beyond the upper-right corner of the image. The powerful radiation from these stars evaporates and erodes the dense cloud of cold gas within which the stars formed. The blistered walls of the hollow cloud shine primarily in the blue, green, and red light emitted by excited atoms of hydrogen, nitrogen, oxygen, and sulfur. Particularly striking is the rose-like feature, seen to the right of center, which glows in the red light emitted by hydrogen and sulfur. As the infant stars evaporate the surrounding cloud, they expose dense pockets of gas that may contain developing stars. One isolated pocket is seen at the center of the brightest region of the nebula. Other dense pockets of gas have formed the remarkable feature jutting inward from the left edge of the image. The color image is constructed from four separate images taken in these filters: blue, near infrared, hydrogen alpha, and doubly ionized oxygen. Credit: NASA, H. Ford (JHU), G. Illingworth (USCS/LO), M. Clampin (STScI), G. Hartig (STScI), the ACS Science Team, and ESA.

  5. Bipolar Disorder and Cancer

    Directory of Open Access Journals (Sweden)

    Sermin Kesebir

    2012-06-01

    Full Text Available Prevalence studies and studies on causation relations have shown that the relation between psychiatric disorders and chronic physical diseases is neglected. For heterogeneous diseases an increasing number of susceptibility variants are being defined. Alzheimer disease, bipolar disorder, breast and prostate cancer, coronary artery disease, Chron's disease, systemic lupus eritematosus, type 1 and type 2 diabetes mellitus are mentioned together with epigenetic concept. In acrocentric zone of chromosome 13, breast cancer, retinoblastoma, chronic Iymphocytic leukemia genes with B cells, dopamin loci of bipolar disorder are found together. Among bipolar and healthy individuals, an increase risk of breast cancer in female cases has been resported. On the other hand, psychosocial factors that affect stress and response to stress itself may be important variables in prognosis and progression of different cancer types. During the course of many cancer types –especially brain tumors- and during treatment of chemotherapeutic agents, bipolar symptomatology may appear. In this article, it is reviewed with relevant literature that whether an etiological relation between bipolar disorder and cancer exist and how both diseases affect each other's course and treatment.

  6. The interaction of the halo around the butterfly planetary nebula NGC 650-1 with the interstellar medium

    Science.gov (United States)

    Ramos-Larios, G.; Guerrero, M. A.; Nigoche-Netro, A.; Olguín, L.; Gómez-Muñoz, M. A.; Sabin, L.; Vázquez, R.; Akras, S.; Ramírez Vélez, J. C.; Chávez, M.

    2018-03-01

    With its bright and wide equatorial waist seen almost edge-on (`the butterfly body') and the faint and broad bipolar extensions (`the butterfly wings'), NGC 650-1 is the archetypical example of bipolar planetary nebula (PN) with butterfly morphology. We present here deep high-resolution broad- and narrow-band optical images that expose the rich and intricate fine structure of this bipolar PN, with small-scale bubble-like features and collimated outflows. A SHAPE spatio-kinematic model indicates that NGC 650-1 has a broad central torus with an inclination angle of 75° with respect to the line of sight, whereas that of the bipolar lobes, which are clearly seen in the position-velocity maps, is 85°. Large field of view deep images show, for first time, an arc-like diffuse envelope in low- and high-excitation emission lines located up to 180 arcsec towards the east-south-east of the central star, well outside the main nebula. This morphological component is confirmed by Spitzer MIPS and WISE infrared imaging, as well as by long-slit low- and high-dispersion optical spectroscopic observations. Hubble Space Telescope images of NGC 650-1 obtained at two different epochs ˜14 yr apart reveal the proper motion of the central star along this direction. We propose that this motion of the star through the interstellar medium compresses the remnant material of a slow asymptotic giant branch wind, producing this bow-shock-like feature.

  7. An IFU-view of Planetary Nebulae: Exploring NGC 6720 (Ring Nebula) with KCWI

    Science.gov (United States)

    Hoadley, Keri; Matuszewski, Matt; Hamden, Erika; Martin, Christopher; Neill, Don; Kyne, Gillian

    2018-01-01

    Studying the interaction between the ejected stellar material and interstellar clouds is important for understanding how stellar deaths influences the pollution of matter that will later form other stars. Planetary nebulae provide ideal laboratories to study such interactions. I will present on a case study of one close-by planetary nebula, the Ring Nebula (M 57, NGC 6720), to infer the abundances, temperatures, structures, and dynamics of important atomic and ionic species in two distinct regions of the nebula using a newly-commissioned integral field spectrograph (IFS) on Keck: the Keck Cosmic Web Imager (KCWI). The advantage of an IFS over traditional filter-imaging techniques is the ability to simultaneously observe the spectrum of any given pixel in the imaging area, which provides crucial information about the dynamics of the observed region. This technique is powerful for diffuse or extended astrophysical objects, and I will demonstrate the different imaging and spectral modes of KCWI used to observe the Ring Nebula.KCWI observations of the Ring Nebula focused mainly on the innermost region of the nebula, with a little coverage of the Inner Ring. We also observed the length of the Ring in one set of observations, for which we will estimate the elemental abundances, temperatures, and dynamics of the region. KCWI observations also capture an inner arc and blob that have distinctly difference characteristics than the Ring itself and may be a direct observation of either the planetary nebula ramming into an interstellar cloud projected onto the sightline or a dense interstellar cloud being illuminated by the stellar continuum from the hot central white dwarf.

  8. Angular diameters of Magellanic Cloud plantary nebulae. I. Speckle interferometry

    International Nuclear Information System (INIS)

    Wood, P.R.; Bessell, M.S.; Dopita, M.A.

    1986-01-01

    Speckle interferometric angular diameters of Magellanic Cloud planetary nebulae are presented. The mass of ionized gas in each nebula has been derived from the angular diameter and published H-beta line fluxes; the derives masses range from less than 0.006 to more than 0.19 solar mass. The planetary nebulae observed were the brightest in the Magellanic Clouds; consequently, they are all relatively small, young, bright, and dense. They are almost certainly only partially ionized, so that the masses derived for the ionized parts of the nebula are lower limits to the total nebula mass. The properties of the Magellanic Cloud nebulae are compared with those of planetary nebulae at the galactic center. 27 references

  9. HM Sagittae as a young planetary nebula

    International Nuclear Information System (INIS)

    Kwok, S.; Purton, C.R.

    1979-01-01

    HM Sagittae is suggested to be a very young planetary nebula recently transformed from a red-giant star through continuous mass loss. The observational data for HM Sge have been analyzed in terms of the interacting stellar wind model of planetary nebula formation. The model is in accord with virtually all the spectral data available--radio, optical, and infrared--as well as with the remarkable brightening of HM Sge observed in 1975. In particular, all three gaseous components predicted by the model are observed in the optical spectrum. The density in the newly formed shell is found to be at least 5 x 10 7 cm -3 , a value considerably higher than that found by the conventional analysis, which assumes a single-component homogeneous nebula. The radio spectrum is dominated by free-free emission from the remnant red-giant wind. The infrared spectrum suggests the presence of two dust components, one consisting of silicate grains left over from the red-giant stage and the other of grains newly formed after the 1975 brightening. The low observed shell mass is consistent with the interacting stellar wind model but is not consistent with the conventional sudden-ejection model of planetary nebula formation

  10. Turbulent Magnetic Relaxation in Pulsar Wind Nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Zrake, Jonathan [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Arons, Jonathan [Astronomy Department and Theoretical Astrophysics Center, University of California, Berkeley, 601 Campbell Hall, Berkeley, CA 94720 (United States)

    2017-09-20

    We present a model for magnetic energy dissipation in a pulsar wind nebula. A better understanding of this process is required to assess the likelihood that certain astrophysical transients may be powered by the spin-down of a “millisecond magnetar.” Examples include superluminous supernovae, gamma-ray bursts, and anticipated electromagnetic counterparts to gravitational wave detections of binary neutron star coalescence. Our model leverages recent progress in the theory of turbulent magnetic relaxation to specify a dissipative closure of the stationary magnetohydrodynamic (MHD) wind equations, yielding predictions of the magnetic energy dissipation rate throughout the nebula. Synchrotron losses are self-consistently treated. To demonstrate the model’s efficacy, we show that it can reproduce many features of the Crab Nebula, including its expansion speed, radiative efficiency, peak photon energy, and mean magnetic field strength. Unlike ideal MHD models of the Crab (which lead to the so-called σ -problem), our model accounts for the transition from ultra to weakly magnetized plasma flow and for the associated heating of relativistic electrons. We discuss how the predicted heating rates may be utilized to improve upon models of particle transport and acceleration in pulsar wind nebulae. We also discuss implications for the Crab Nebula’s γ -ray flares, and point out potential modifications to models of astrophysical transients invoking the spin-down of a millisecond magnetar.

  11. Turbulent Magnetic Relaxation in Pulsar Wind Nebulae

    Science.gov (United States)

    Zrake, Jonathan; Arons, Jonathan

    2017-09-01

    We present a model for magnetic energy dissipation in a pulsar wind nebula. A better understanding of this process is required to assess the likelihood that certain astrophysical transients may be powered by the spin-down of a “millisecond magnetar.” Examples include superluminous supernovae, gamma-ray bursts, and anticipated electromagnetic counterparts to gravitational wave detections of binary neutron star coalescence. Our model leverages recent progress in the theory of turbulent magnetic relaxation to specify a dissipative closure of the stationary magnetohydrodynamic (MHD) wind equations, yielding predictions of the magnetic energy dissipation rate throughout the nebula. Synchrotron losses are self-consistently treated. To demonstrate the model’s efficacy, we show that it can reproduce many features of the Crab Nebula, including its expansion speed, radiative efficiency, peak photon energy, and mean magnetic field strength. Unlike ideal MHD models of the Crab (which lead to the so-called σ-problem), our model accounts for the transition from ultra to weakly magnetized plasma flow and for the associated heating of relativistic electrons. We discuss how the predicted heating rates may be utilized to improve upon models of particle transport and acceleration in pulsar wind nebulae. We also discuss implications for the Crab Nebula’s γ-ray flares, and point out potential modifications to models of astrophysical transients invoking the spin-down of a millisecond magnetar.

  12. Large proper motions in the Orion nebula

    International Nuclear Information System (INIS)

    Cudworth, K.M.; Stone, R.C.

    1977-01-01

    Several nebular features, as well as one faint star, with large proper motions were identified within the Orion nebula. The measured proper motions correspond to tangential velocities of up to approximately 70 km sec -1 . One new probable variable star was also found

  13. INTERNAL PROPER MOTIONS IN THE ESKIMO NEBULA

    International Nuclear Information System (INIS)

    García-Díaz, Ma. T.; Gutiérrez, L.; Steffen, W.; López, J. A.; Beckman, J.

    2015-01-01

    We present measurements of internal proper motions at more than 500 positions of NGC 2392, the Eskimo Nebula, based on images acquired with WFPC2 on board the Hubble Space Telescope at two epochs separated by 7.695 yr. Comparisons of the two observations clearly show the expansion of the nebula. We measured the amplitude and direction of the motion of local structures in the nebula by determining their relative shift during that interval. In order to assess the potential uncertainties in the determination of proper motions in this object, in general, the measurements were performed using two different methods, used previously in the literature. We compare the results from the two methods, and to perform the scientific analysis of the results we choose one, the cross-correlation method, because it is more reliable. We go on to perform a ''criss-cross'' mapping analysis on the proper motion vectors, which helps in the interpretation of the velocity pattern. By combining our results of the proper motions with radial velocity measurements obtained from high resolution spectroscopic observations, and employing an existing 3D model, we estimate the distance to the nebula to be 1.3 kpc

  14. INTERNAL PROPER MOTIONS IN THE ESKIMO NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    García-Díaz, Ma. T.; Gutiérrez, L.; Steffen, W.; López, J. A. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Km 103 Carretera Tijuana-Ensenada, 22860 Ensenada, B.C. (Mexico); Beckman, J., E-mail: tere@astro.unam.mx, E-mail: leonel@astro.unam.mx, E-mail: wsteffen@astro.unam.mx, E-mail: jal@astro.unam.mx, E-mail: jeb@iac.es [Instituto de Astrofísica de Canarias, La Laguna, Tenerife (Spain)

    2015-01-10

    We present measurements of internal proper motions at more than 500 positions of NGC 2392, the Eskimo Nebula, based on images acquired with WFPC2 on board the Hubble Space Telescope at two epochs separated by 7.695 yr. Comparisons of the two observations clearly show the expansion of the nebula. We measured the amplitude and direction of the motion of local structures in the nebula by determining their relative shift during that interval. In order to assess the potential uncertainties in the determination of proper motions in this object, in general, the measurements were performed using two different methods, used previously in the literature. We compare the results from the two methods, and to perform the scientific analysis of the results we choose one, the cross-correlation method, because it is more reliable. We go on to perform a ''criss-cross'' mapping analysis on the proper motion vectors, which helps in the interpretation of the velocity pattern. By combining our results of the proper motions with radial velocity measurements obtained from high resolution spectroscopic observations, and employing an existing 3D model, we estimate the distance to the nebula to be 1.3 kpc.

  15. THE CHANDRA X-RAY SURVEY OF PLANETARY NEBULAE (CHANPLANS): PROBING BINARITY, MAGNETIC FIELDS, AND WIND COLLISIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kastner, J. H.; Montez, R. Jr.; Rapson, V. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA (United States); Frew, D. J.; De Marco, O.; Parker, Q. A. [Department of Physics and Astronomy and Macquarie Research Centre for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, NSW 2109 (Australia); Miszalski, B. [South African Astronomical Observatory, P.O. Box 9, Observatory, 7935 (South Africa); Sahai, R. [Jet Propulsion Laboratory, California Institute of Technology, MS 183-900, Pasadena, CA 91109 (United States); Blackman, E.; Frank, A. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Chu, Y.-H. [Department of Astronomy, University of Illinois, Champagne-Urbana, IL (United States); Guerrero, M. A. [Instituto de Astrofisica de Astronomia, Glorieta de la Astronomia s/n, Granada 18008 (Spain); Lopez, J. A. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Campus Ensenada, Apdo. Postal 22860, Ensenada, B. C. (Mexico); Zijlstra, A. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Behar, E. [Department of Physics, Technion (Israel); Bujarrabal, V. [Observatorio Astronomico Nacional, Apartado 112, E-28803, Alcala de Henares (Spain); Corradi, R. L. M. [Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain); Nordhaus, J. [Center for Computational Relativity and Gravitation, Rochester Institute of Technology, Rochester, NY 14623 (United States); Sandin, C., E-mail: jhk@cis.rit.edu, E-mail: soker@physics.technion.ac.il, E-mail: eva.villaver@uam.es [Leibniz Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); and others

    2012-08-15

    We present an overview of the initial results from the Chandra Planetary Nebula Survey (CHANPLANS), the first systematic (volume-limited) Chandra X-Ray Observatory survey of planetary nebulae (PNe) in the solar neighborhood. The first phase of CHANPLANS targeted 21 mostly high-excitation PNe within {approx}1.5 kpc of Earth, yielding four detections of diffuse X-ray emission and nine detections of X-ray-luminous point sources at the central stars (CSPNe) of these objects. Combining these results with those obtained from Chandra archival data for all (14) other PNe within {approx}1.5 kpc that have been observed to date, we find an overall X-ray detection rate of {approx}70% for the 35 sample objects. Roughly 50% of the PNe observed by Chandra harbor X-ray-luminous CSPNe, while soft, diffuse X-ray emission tracing shocks-in most cases, 'hot bubbles'-formed by energetic wind collisions is detected in {approx}30%; five objects display both diffuse and point-like emission components. The presence (or absence) of X-ray sources appears correlated with PN density structure, in that molecule-poor, elliptical nebulae are more likely to display X-ray emission (either point-like or diffuse) than molecule-rich, bipolar, or Ring-like nebulae. All but one of the point-like CSPNe X-ray sources display X-ray spectra that are harder than expected from hot ({approx}100 kK) central stars emitting as simple blackbodies; the lone apparent exception is the central star of the Dumbbell nebula, NGC 6853. These hard X-ray excesses may suggest a high frequency of binary companions to CSPNe. Other potential explanations include self-shocking winds or PN mass fallback. Most PNe detected as diffuse X-ray sources are elliptical nebulae that display a nested shell/halo structure and bright ansae; the diffuse X-ray emission regions are confined within inner, sharp-rimmed shells. All sample PNe that display diffuse X-ray emission have inner shell dynamical ages {approx}< 5 Multiplication

  16. Types of Bipolar Disorder

    Science.gov (United States)

    ... Events Home Science News Meetings and Events Multimedia Social Media Press Resources Newsletters NIMH News Feeds About Us ... has a lot of money, or has special powers. Someone having psychotic symptoms ... Substance Abuse: People with bipolar disorder may also misuse alcohol ...

  17. Discrete bipolar universal integrals

    Czech Academy of Sciences Publication Activity Database

    Greco, S.; Mesiar, Radko; Rindone, F.

    2014-01-01

    Roč. 252, č. 1 (2014), s. 55-65 ISSN 0165-0114 R&D Projects: GA ČR GAP402/11/0378 Institutional support: RVO:67985556 Keywords : bipolar integral * universal integral * Choquet integral Subject RIV: BA - General Mathematics Impact factor: 1.986, year: 2014 http://library.utia.cas.cz/separaty/2014/E/mesiar-0432224.pdf

  18. El trastorno bipolar

    OpenAIRE

    Freaza Rodríguez, Paula

    2014-01-01

    Se exponen los aspectos más relevantes del trastorno bipolar, entender qué significa este concepto, conocer los tipos que existen, qué otros trastornos suelen aparecer al mismo tiempo y qué tratamientos son los que dan mejores resultados

  19. ON BIPOLAR SINGLE VALUED NEUTROSOPHIC GRAPHS

    OpenAIRE

    Said Broumi; Mohamed Talea; Assia Bakali; Florentin Smarandache

    2016-01-01

    In this article, we combine the concept of bipolar neutrosophic set and graph theory. We introduce the notions of bipolar single valued neutrosophic graphs, strong bipolar single valued neutrosophic graphs, complete bipolar single valued neutrosophic graphs, regular bipolar single valued neutrosophic graphs and investigate some of their related properties.

  20. Starlight excitation of permitted lines in gaseous nebulae

    International Nuclear Information System (INIS)

    Grandi, S.A.

    1975-01-01

    The weak heavy element permitted lines observed in the spectra of gaseous nebula have, with only a few exceptions, been thought to be excited only by recombination. The accuracy of this assumption for individual lines in nebula spectra is investigated in detail via model nebula calculations. First, approximations and techniques of calculation are considered for the three possible excitation mechanisms: recombination, resonance fluorescence by the starlight continuum, and resonance fluorescence by other nebular emission lines. Next, the permitted lines of O I as observed in gaseous nebulae are discussed. Thirdly, it is shown that varying combinations of recombination, resonance fluorescence by starlight, and resonance fluorescence by other nebula lines can successfully account for the observed strengths in the Orion Nebula of lines of the following ions: C II, N I, N II, N III, O II, Ne II, Si II, Si III, and S III. A similar analysis is performed for the lines in the spectra of the planetary nebulae NGC7662 and NGC7027, and, with some exceptions, satisfactory agreement between the observed and predicted line strengths is found. Finally, observations of the far red spectra of the Orion Nebula, the planetary nebulae NGC3242, NGC6210, NGC2392, IC3568, IC4997, NGC7027, and MGC7662, and the reflection nebulae IC431 and NGC2068 are reported

  1. The double-degenerate, super-Chandrasekhar nucleus of the planetary nebula Henize 2-428.

    Science.gov (United States)

    Santander-García, M; Rodríguez-Gil, P; Corradi, R L M; Jones, D; Miszalski, B; Boffin, H M J; Rubio-Díez, M M; Kotze, M M

    2015-03-05

    The planetary nebula stage is the ultimate fate of stars with masses one to eight times that of the Sun (M(⊙)). The origin of their complex morphologies is poorly understood, although several mechanisms involving binary interaction have been proposed. In close binary systems, the orbital separation is short enough for the primary star to overfill its Roche lobe as the star expands during the asymptotic giant branch phase. The excess gas eventually forms a common envelope surrounding both stars. Drag forces then result in the envelope being ejected into a bipolar planetary nebula whose equator is coincident with the orbital plane of the system. Systems in which both stars have ejected their envelopes and are evolving towards the white dwarf stage are said to be double degenerate. Here we report that Henize 2-428 has a double-degenerate core with a combined mass of ∼1.76M(⊙), which is above the Chandrasekhar limit (the maximum mass of a stable white dwarf) of 1.4M(⊙). This, together with its short orbital period (4.2 hours), suggests that the system should merge in 700 million years, triggering a type Ia supernova event. This supports the hypothesis of the double-degenerate, super-Chandrasekhar evolutionary pathway for the formation of type Ia supernovae.

  2. Extended Structures of Planetary Nebulae Detected in H2 Emission

    Science.gov (United States)

    Fang, Xuan; Zhang, Yong; Kwok, Sun; Hsia, Chih-Hao; Chau, Wayne; Ramos-Larios, Gerardo; Guerrero, Martín A.

    2018-06-01

    We present narrowband near-infrared images of a sample of 11 Galactic planetary nebulae (PNe) obtained in the H2 2.122 μm and Brγ 2.166 μm emission lines and the K c 2.218 μm continuum. These images were collected with the Wide-field Infrared Camera on the 3.6 m Canada–France–Hawaii Telescope (CFHT); their unprecedented depth and wide field of view allow us to find extended nebular structures in H2 emission in several PNe, some of these being the first detection. The nebular morphologies in H2 emission are studied in analogy with the optical images, and indication of stellar wind interactions is discussed. In particular, the complete structure of the highly asymmetric halo in NGC 6772 is witnessed in H2, which strongly suggests interaction with the interstellar medium. Our sample confirms the general correlation between H2 emission and the bipolarity of PNe. The knotty or filamentary fine structures of the H2 gas are resolved in the inner regions of several ring-like PNe, also confirming the previous argument that H2 emission mostly comes from knots or clumps embedded within fully ionized material at the equatorial regions. Moreover, the H2 image of the butterfly-shaped Sh 1-89, after removal of field stars, clearly reveals a tilted ring structure at the waist. These high-quality CFHT images justify follow-up detailed morphokinematic studies that are desired in order to deduce the true physical structures of a few PNe in the sample. Based on observations obtained with WIRCam, a joint project of CFHT, Taiwan, Korea, Canada, and France, at the Canada–France–Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

  3. The evolution of meteorites and planets from a hot nebula

    Directory of Open Access Journals (Sweden)

    Donald H. Tarling

    2015-06-01

    Full Text Available Meteorites have a hot origin as planetary materials derive from a supernova, similar to SN1987A, and were acquired by a nearby nova, the Sun. The supernova plasmas became zoned around the nova, mainly by their electromagnetic properties. Carbon and carbide dusts condensed first, followed, within the Inner Planetary Zone, by Ca–Mg–Al oxides and then by iron and nickel metal droplets. In the inner Asteroid Belt, the metals aggregated into clumps as they solidified but over a much longer time in the Inner Zone. ‘Soft’ collisions formed larger (<∼20 km objects in the Asteroid Belt; in the Inner Zone these aggregated forming proto-planetary cores during inwards orbital migration. In the Asteroid Belt, glassy olivines condensed, followed more open lattice minerals growing grew primarily by diffusion. Brittle silicate crystals were comminuted and only aggregated into the carbonaceous meteorites when water–ices formed. The inner planets differentiated by at least 4.4 Ga. Jupiter and the outer planets grew on asteroidal bodies thrown out into freezing water vapours and only formed by 4.1 Ga, resulting in the Late Heavy Bombardment, initially by meteoritic materials and later supplemented by ices from, and beyond, the Asteroid Belt. Critical factors are the properties of very high temperature supernova plasmas, the duration of the molten iron phase in the inner zone. Evidence usually quoted for a cold origin derives from late stage processes in hot meteorite evolution. While highly speculative, it is shown that meteorites and planets can be formed by known processes as supernova plasmas cool.

  4. Gamma-rays and neutrinos from the pulsar wind nebulae

    International Nuclear Information System (INIS)

    Bednarek, W.; Bartosik, M.

    2005-01-01

    We construct the time-dependent radiation model for the pulsar wind nebulae (PWNe), assuming that leptons are accelerated in resonant scattering with heavy nuclei, which are injected into the nebula by the pulsar. The equilibrium spectra of these particles inside the nebula are calculated taking into account their radiation and adiabatic energy losses. The spectra of γ-rays produced by these particles are compared with the observations of the PWNe emitting TeV γ-rays and predictions are made for the expected γ-ray fluxes from other PWNe. Expected neutrino fluxes and neutrino event rates in a 1 km 2 neutrino detector from these nebulae are also calculated. It is concluded that only the Crab Nebula can produce a detectable neutrino event rate in the 1 km 2 neutrino detector. Other PWNe can emit TeV γ-rays on the level of a few percent of that observed from the Crab Nebula

  5. Life expectancy in bipolar disorder

    DEFF Research Database (Denmark)

    Kessing, Lars Vedel; Vradi, Eleni; Andersen, Per Kragh

    2015-01-01

    OBJECTIVE: Life expectancy in patients with bipolar disorder has been reported to be decreased by 11 to 20 years. These calculations are based on data for individuals at the age of 15 years. However, this may be misleading for patients with bipolar disorder in general as most patients have a later...... onset of illness. The aim of the present study was to calculate the remaining life expectancy for patients of different ages with a diagnosis of bipolar disorder. METHODS: Using nationwide registers of all inpatient and outpatient contacts to all psychiatric hospitals in Denmark from 1970 to 2012 we...... remaining life expectancy in bipolar disorder and that of the general population decreased with age, indicating that patients with bipolar disorder start losing life-years during early and mid-adulthood. CONCLUSIONS: Life expectancy in bipolar disorder is decreased substantially, but less so than previously...

  6. FACT. Energy spectrum of the Crab Nebula

    Energy Technology Data Exchange (ETDEWEB)

    Temme, Fabian; Einecke, Sabrina; Buss, Jens [TU Dortmund, Experimental Physics 5, Otto-Hahn-Str.4, 44221 Dortmund (Germany); Collaboration: FACT-Collaboration

    2016-07-01

    The First G-APD Cherenkov Telescope is the first Imaging Air Cherenkov Telescope which uses silicon photon detectors (G-APDs aka SiPM) as photo sensors. With more than four years of operation, FACT proved an application of SiPMs is suitable for the field of ground-based gamma-ray astronomy. Due to the stable flux at TeV energies, the Crab Nebula is handled as a ''standard candle'' in Cherenkov astronomy. The analysis of its energy spectrum and comparison with other experiments, allows to evaluate the performance of FACT. A modern analysis chain, based on data stream handling and multivariate analysis methods was developed in close cooperation with the department of computer science at the TU Dortmund. In this talk, this analysis chain and its application are presented. Further to this, results, including the energy spectrum of the Crab Nebula, measured with FACT, are shown.

  7. [Bipolar disorder in adolescence].

    Science.gov (United States)

    Brunelle, Julie; Milhet, Vanessa; Consoli, Angèle; Cohen, David

    2014-04-01

    Juvenile mania is a concept widely developed but also highly debated since the 1990s. In the heart of this debate, Severe Mood Dysregulation (SMD) and "Temper Dysregulation disorder with Dysphoria" (recently integrated in DSM-5) showed their interest. Actually, the objective is to distinguish two clinical phenotypes in order to avoid confusion between (1) what would raise more of mood dysregulation with chronic manic like symptoms, and (2) bipolar disorder type I with episodic and acute manic episodes. Therapeutic stakes are major. In adolescents, even if DSM adult diagnostic criteria can be used and bipolar disorder type I clearly established, differential diagnostic at onset between acute manic episode and schizophrenia onset remain sometimes difficult to assess. Furthermore, it is crucial to better assess outcome of these adolescents, in terms of morbidity and potential prognosis factors, knowing that a younger age at onset is associated with a poorer outcome according to several adult studies. Therapeutic implications could then be drawn.

  8. Depressive and bipolar disorders

    DEFF Research Database (Denmark)

    Kessing, Lars Vedel; Hansen, Hanne Vibe; Demyttenaere, Koen

    2005-01-01

    of the patients (40-80%) had erroneous views as to the effect of antidepressants. Older patients (over 40 years of age) consistently had a more negative view of the doctor-patient relationship, more erroneous ideas concerning the effect of antidepressants and a more negative view of antidepressants in general....... Moreover, their partners agreed on these negative views. Women had a more negative view of the doctor-patient relationship than men, and patients with a depressive disorder had a more negative view of antidepressants than patients with bipolar disorder. The number of psychiatric hospitalizations......BACKGROUND: There is increasing evidence that attitudes and beliefs are important in predicting adherence to treatment and medication in depressive and bipolar disorders. However, these attitudes have received little study in patients whose disorders were sufficiently severe to require...

  9. Nebulae at keratoconus--the result after excimer laser removal.

    Science.gov (United States)

    Fagerholm, P; Fitzsimmons, T; Ohman, L; Orndahl, M

    1993-12-01

    Ten patients underwent excimer laser ablation due to nebula formation at keratoconus. The nebulae interfered significantly with contact lens fit or wearing time. The mean follow-up time in these patients was 16.5 months. Following surgery all patients could be successfully fitted with a contact lens and thereby obtain good visual acuity. Furthermore, contact lens wearing time was 8 hours or more in all cases. In 2 patients the nebulae recurred but were successfully retreated.

  10. Astrophysics of gaseous nebulae and active galactic nuclei

    International Nuclear Information System (INIS)

    Osterbrock, D.E.

    1989-01-01

    A graduate-level text and reference book on gaseous nebulae and the emission regions in Seyfert galaxies, quasars, and other types of active galactic nuclei (AGN) is presented. The topics discussed include: photoionization equilibrium, thermal equilibrium, calculation of emitted spectrum, comparison of theory with observations, internal dynamics of gaseous nebulae, interstellar dust, regions in the galactic context, planetary nebulae, nova and supernova remnants, diagnostics and physics of AGN, observational results on AGN

  11. Bipolar Plates for PEM Systems

    OpenAIRE

    Lædre, Sigrid

    2016-01-01

    Summary of thesis: The Bipolar Plate (BPP) is an important component in both Proton Exchange Membrane Fuel Cells (PEMFCs) and Proton Exchange Membrane Water Electrolyzers (PEMWEs). Bipolar plate material and processing constitutes for a large fraction of the cost and weight of a PEM cell stack. The main tasks for the bipolar plates in both systems are to separate single cell in a stack, conduct current between single cells and remove heat from active areas. In addition, the BPPs distribu...

  12. Nebula observations. Catalogues and archive of photoplates

    Science.gov (United States)

    Shlyapnikov, A. A.; Smirnova, M. A.; Elizarova, N. V.

    2017-12-01

    A process of data systematization based on "Academician G.A. Shajn's Plan" for studying the Galaxy structure related to nebula observations is considered. The creation of digital versions of catalogues of observations and publications is described, as well as their presentation in HTML, VOTable and AJS formats and basic principles of work in the interactive application of International Virtual Observatory the Aladin Sky Atlas.

  13. Multiband observations of the Crab Nebula

    International Nuclear Information System (INIS)

    Krassilchtchikov, A M; Bykov, A M; Castelletti, G M; Dubner, G M; Kargaltsev, O Yu; Pavlov, G G

    2017-01-01

    Results of simultaneous imaging of the Crab Nebula in the radio (JVLA), optical ( HST ), and X-ray ( Chandra ) bands are presented. The images show a variety of small-scale structures, including wisps mainly located to the north-west of the pulsar and knots forming a ring-like structure associated with the termination shock of the pulsar wind. The locations of the structures in different bands do not coincide with each other. (paper)

  14. [Creativity and bipolar disorder].

    Science.gov (United States)

    Maçkalı, Zeynep; Gülöksüz, Sinan; Oral, Timuçin

    2014-01-01

    The relationship between creativity and bipolar disorder has been an intriguing topic since ancient times. Early studies focused on describing characteristics of creative people. From the last quarter of the twentieth century, researchers began to focus on the relationship between mood disorders and creativity. Initially, the studies were based on biographical texts and the obtained results indicated a relationship between these two concepts. The limitations of the retrospective studies led the researchers to develop systematic investigations into this area. The systematic studies that have focused on artistic creativity have examined both the prevalence of mood disorders and the creative process. In addition, a group of researchers addressed the relationship in terms of affective temperaments. Through the end of the 90's, the scope of creativity was widened and the notion of everyday creativity was proposed. The emergence of this notion led researchers to investigate the associations of the creative process in ordinary (non-artist) individuals. In this review, the descriptions of creativity and creative process are mentioned. Also, the creative process is addressed with regards to bipolar disorder. Then, the relationship between creativity and bipolar disorder are evaluated in terms of aforementioned studies (biographical, systematic, psychobiographical, affective temperaments). In addition, a new model, the "Shared Vulnerability Model" which was developed to explain the relationship between creativity and psychopathology is introduced. Finally, the methodological limitations and the suggestions for resolving these limitations are included.

  15. Reviewing metallic PEMFC bipolar plates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.; Turner, J.A. [National Renewable Energy Laboratory, Golden, CO (United States)

    2010-08-15

    A bipolar plate is one of the most important components in a polymer exchange membrane fuel cell (PEMFC) stack and has multiple functions. Metallic bipolar plate candidates have advantages over composite rivals in excellent electrical and thermal conductivity, good mechanical strength, high chemical stability, very wide alloy choices, low cost and, most importantly, existing pathways for high-volume, high-speed mass production. The challenges with metallic bipolar plates are the higher contact resistance and possible corrosion products, which may contaminate the membrane electrode assembly. This review evaluates the candidate metallic and coating materials for bipolar plates and gives the perspective of the research trends. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  16. Environmental impact study of Orion Nebula dust

    International Nuclear Information System (INIS)

    Cardelli, J.A.; Clayton, G.C.

    1988-01-01

    In this paper, new high-quality extinction curves are presented for Theta-1 Ori A, C, and D, and Theta-2 Ori A and B, over the wavelength range 3300-6000 A. These are coupled with near-infrared and ultraviolet data to produce extinction curves from 0.12 to 3.5 microns. The Orion Nebula region is interesting in that most of the known processes of dust-grain growth, processing, and destruction may be operating nearly simultaneously in close proximity to one another. Each of these processes is considered with respect to the observed extinction curves and environmental conditions in the Orion Nebula and its associated molecular cloud. Plausible grain populations are fit to the observed extinction curves. A good fit to the average Theta Ori extinction curve can be obtained with: (1) a combination of larger than normal silicate grains produced through coagulation and accretion; (2) evaporation of volatile mantles; and (3) a reduction in the column density of small (smaller than 0.01 micron) grains responsible for the bump and far-ultraviolet extinction through differential acceleration due to radiation pressure and possible evaporation. It seems plausible to explain the observed peculiar extinction in the Orion Nebula simply by environmental effects on otherwise normal grains. 59 references

  17. of Planetary Nebulae III. NGC 6781

    Directory of Open Access Journals (Sweden)

    Hugo E. Schwarz

    2006-01-01

    Full Text Available Continuing our series of papers on the three-dimensional (3D structures and accurate distances to Planetary Nebulae (PNe, we present our study of the planetary nebula NGC6781. For this object we construct a 3D photoionization model and, using the constraints provided by observational data from the literature we determine the detailed 3D structure of the nebula, the physical parameters of the ionizing source and the first precise distance. The procedure consists in simultaneously fitting all the observed emission line morphologies, integrated intensities and the two-dimensional (2D density map from the [SII] (sulfur II line ratios to the parameters generated by the model, and in an iterative way obtain the best fit for the central star parameters and the distance to NGC6781, obtaining values of 950±143 pc (parsec – astronomic distance unit and 385 LΘ (solar luminosity for the distance and luminosity of the central star respectively. Using theoretical evolutionary tracks of intermediate and low mass stars, we derive the mass of the central star of NGC6781 and its progenitor to be 0.60±0.03MΘ (solar mass and 1.5±0.5MΘ respectively.

  18. 3He Abundances in Planetary Nebulae

    Science.gov (United States)

    Guzman-Ramirez, Lizette

    2017-10-01

    Determination of the 3He isotope is important to many fields of astrophysics, including stellar evolution, chemical evolution, and cosmology. The isotope is produced in stars which evolve through the planetary nebula phase. Planetary nebulae are the final evolutionary phase of low- and intermediate-mass stars, where the extensive mass lost by the star on the asymptotic giant branch is ionised by the emerging white dwarf. This ejecta quickly disperses and merges with the surrounding ISM. 3He abundances in planetary nebulae have been derived from the hyperfine transition of the ionised 3He, 3He+, at the radio rest frequency 8.665 GHz. 3He abundances in PNe can help test models of the chemical evolution of the Galaxy. Many hours have been put into trying to detect this line, using telescopes like the Effelsberg 100m dish of the Max Planck Institute for Radio Astronomy, the National Radio Astronomy Observatory (NRAO) 140-foot telescope, the NRAO Very Large Array, the Arecibo antenna, the Green Bank Telescope, and only just recently, the Deep Space Station 63 antenna from the Madrid Deep Space Communications Complex.

  19. A PHOTOMETRICALLY AND MORPHOLOGICALLY VARIABLE INFRARED NEBULA IN L483

    International Nuclear Information System (INIS)

    Connelley, Michael S.; Hodapp, Klaus W.; Fuller, Gary A.

    2009-01-01

    We present narrow and broad K-band observations of the Class 0/I source IRAS 18148-0440 that span 17 years. The infrared nebula associated with this protostar in the L483 dark cloud is both morphologically and photometrically variable on a timescale of only a few months. This nebula appears to be an infrared analog to other well known optically visible variable nebulae associated with young stars, such as Hubble's Variable Nebula. Along with Cepheus A, this is one of the first large variable nebulae to be found that is only visible in the infrared. The variability of this nebula is most likely due to changing illumination of the cloud rather than any motion of the structure in the nebula. Both morphological and photometric changes are observed on a timescale only a few times longer than the light crossing time of the nebula, suggesting very rapid intrinsic changes in the illumination of the nebula. Our narrowband observations also found that H 2 knots are found nearly twice as far to the east of the source as to its west, and that H 2 emission extends farther east of the source than the previously known CO outflow.

  20. A BUTTERFLY-SHAPED 'PAPILLON' NEBULA YIELDS SECRETS OF MASSIVE STAR BIRTH

    Science.gov (United States)

    2002-01-01

    A NASA Hubble Space Telescope view of a turbulent cauldron of starbirth, called N159, taking place 170,000 light-years away in our satellite galaxy, the Large Magellanic Cloud (LMC). Torrential stellar winds from hot newborn massive stars within the nebula sculpt ridges, arcs, and filaments in the vast cloud, which is over 150 light-years across. A rare type of compact ionized 'blob' is resolved for the first time to be a butterfly-shaped or 'Papillon' (French for 'butterfly') nebula, buried in the center of the maelstrom of glowing gases and dark dust. The unprecedented details of the structure of the Papillon, itself less than 2 light-years in size (about 2 arcseconds in the sky), are seen in the inset. A possible explanation of this bipolar shape is the outflow of gas from massive stars (over 10 times the mass of our sun) hidden in the central absorption zone. Such stars are so hot that their radiation pressure halts the infall of gas and directs it away from the stars in two opposite directions. Presumably, a dense equatorial disk formed by matter still trying to fall in onto the stars focuses the outstreaming matter into the bipolar directions. This observation is part of a search for young massive stars in the LMC. Rare are the cases where we can see massive stars so early after their birth. The red in this true-color image is from the emission of hydrogen and the yellow from high excitation ionized oxygen. The picture was taken on September 5, 1998 with the Wide Field Planetary Camera 2. The Hubble observations of the Papillon nebula were conducted by the European astronomers Mohammad Heydari-Malayeri (Paris Observatory, France) and co-investigators Michael Rosa (Space Telescope-European Coordinating Facility, European Southern Observatory, Germany), Vassilis Charmandaris (Paris Observatory), Lise Deharveng (Marseille Observatory, France), and Hans Zinnecker (Astrophysical Institute, Potsdam, Germany). Their work is submitted for publication in the European

  1. M2-9 - a planetary nebula with an eruptive nucleus?

    International Nuclear Information System (INIS)

    Balick, B.

    1989-01-01

    M2-9 is a striking bipolar, or butterfly, planetary nebula (PN) whose nuclear spectrum is uncharacteristic of PN nuclei. Narrow lines ranging in ionization from O I, Fe II, forbidden Fe II, and Si II through forbidden O III are observed in the stellar spectrum. The H-alpha emission line has wings extending nearly 11,000 km/s at the base, and there is a deep self-absorption feature near the H-alpha line peak at the same velocity as nebular gas observed in one of the two bipolar lobes. The spectrum of M2-9's nucleus is more similar to the slow nova RR Tel, some symbiotic stars, and Seyfert (type 1.9) galactic nuclei than the central stars of most other PNs. Although its morphology, size, and nebular spectrum share many similarities with other PNs, M2-9 may not share a common evolutionary history with that class of objects. 31 references

  2. Scientific attitudes towards bipolar disorders

    Directory of Open Access Journals (Sweden)

    Mohammad-Hossein Biglu

    2014-02-01

    Full Text Available Introduction: Bipolar disorder is a psychiatric condition that is also called manic-depressive disease. It causes unusual changes in mood, energy, activity levels, and the ability to carry out day-to-day tasks. In the present study, 3 sets of data were considered and analyzed: first, all papers categorized under Bipolar Disorders in Science Citation Index Expanded (SCI-E database through 2001-2011; second, papers published by the international journal of Bipolar Disorders indexed in SCI-E during a period of 11 years; and third, all papers distributed by the international journal of Bipolar Disorders indexed in MEDLINE during the period of study. Methods: The SCI-E database was used to extract all papers indexed with the topic of Bipolar Disorders as well as all papers published by The International Journal of Bipolar Disorders. Extraction of data from MEDLINE was restricted to the journals name from setting menu. The Science of Science Tool was used to map the co-authorship network of papers published by The International Journal of Bipolar Disorders through 2009-2011. Results: Analysis of data showed that the majority of publications in the subject area of bipolar disorders indexed in SCI-E were published by The International Journal of Bipolar Disorders. Although journal articles consisted of 59% of the total publication type in SCI-E, 65% of publications distributed by The Journal of Bipolar Disorders were in the form of meetingabstracts. Journal articles consisted of only 23% of the total publications. USA was the leading country regarding sharing data in the field of bipolar disorders followed by England, Canada, and Germany. Conclusion: The editorial policy of The International Journal of Bipolar Disorders has been focused on new themes and new ways of researching in the subject area of bipolar disorder. Regarding the selection of papers for indexing, the SCI-E database selects data more comprehensively than MEDLINE. The number of papers

  3. Epidemiology in Pediatric Bipolar Disorder

    Directory of Open Access Journals (Sweden)

    Caner Mutlu

    2015-12-01

    Full Text Available Childhood and adolescent bipolar disorder diagnosis has been increasing recently. Since studies evaluating attempted suicide rates in children and adolescents have shown bipolarity to be a significant risk factor, diagnosis and treatment of bipolarity has become a very important issue. Since there is a lack of specific diagnostic criteria for especially preadolescent samples and evaluations are made mostly symptomatically, suspicions about false true diagnosis and increased prevalence rates have emerged. This situation leads to controversial data about the prevalence rates of bipolar disorder in children and adolescents. The aim of this article is to review the prevalence of childhood and adolescent bipolar disorder in community, inpatient and outpatient based samples in literature.

  4. Genetics of bipolar disorder

    Directory of Open Access Journals (Sweden)

    Kerner B

    2014-02-01

    Full Text Available Berit Kerner Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA Abstract: Bipolar disorder is a common, complex genetic disorder, but the mode of transmission remains to be discovered. Many researchers assume that common genomic variants carry some risk for manifesting the disease. The research community has celebrated the first genome-wide significant associations between common single nucleotide polymorphisms (SNPs and bipolar disorder. Currently, attempts are under way to translate these findings into clinical practice, genetic counseling, and predictive testing. However, some experts remain cautious. After all, common variants explain only a very small percentage of the genetic risk, and functional consequences of the discovered SNPs are inconclusive. Furthermore, the associated SNPs are not disease specific, and the majority of individuals with a “risk” allele are healthy. On the other hand, population-based genome-wide studies in psychiatric disorders have rediscovered rare structural variants and mutations in genes, which were previously known to cause genetic syndromes and monogenic Mendelian disorders. In many Mendelian syndromes, psychiatric symptoms are prevalent. Although these conditions do not fit the classic description of any specific psychiatric disorder, they often show nonspecific psychiatric symptoms that cross diagnostic boundaries, including intellectual disability, behavioral abnormalities, mood disorders, anxiety disorders, attention deficit, impulse control deficit, and psychosis. Although testing for chromosomal disorders and monogenic Mendelian disorders is well established, testing for common variants is still controversial. The standard concept of genetic testing includes at least three broad criteria that need to be fulfilled before new genetic tests should be introduced: analytical validity, clinical validity, and clinical utility. These criteria are

  5. Abundances of the planetary nebula Hu 1-2

    NARCIS (Netherlands)

    Pottasch, [No Value; Hyung, S; Aller, LH; Beintema, DA; Bernard-Salas, J; Feibelman, WA; Klockner, HR

    The ISO and IUE spectra of the "elliptical" nebula Hu 1-2 are presented. These spectra are combined with new, high resolution spectra in the visual wavelength region to obtain a complete, extinction corrected, spectrum. The chemical composition of the nebula is then calculated and compared to

  6. Abundances of planetary nebulae NGC 7662 and NGC 6741

    NARCIS (Netherlands)

    Pottasch, [No Value; Beintema, DA; Salas, JB; Feibelman, WA

    2001-01-01

    The ISO and IUE spectra of the elliptical nebulae NGC7662 and NGC6741 are presented. These spectra are combined with the spectra in the visual wavelength region to obtain a complete, extinction corrected, spectrum. The chemical composition of the nebulae is then calculated and compared to previous

  7. Starlight excitation of permitted lines in the Orion Nebula

    International Nuclear Information System (INIS)

    Grandi, S.A.

    1975-01-01

    From an idealized model of the Orion Nebula and from an analysis of line ratios it is shown that direct starlight excitation of the permitted O I line dominates over recombination and Lyman line fluorescence. The line strengths predicted by this mechanism agree reasonably well with those observed in the Orion Nebula. The application of direct starlight excitation to other ions is also discussed

  8. A comparison of Hipparcos parallaxes with planetary nebulae spectroscopic distances

    NARCIS (Netherlands)

    Pottasch, [No Value; Acker, A

    1998-01-01

    The Hipparcos satellite has measured the parallax of a small sample of planetary nebulae. In this paper we consider the results for 3 planetary nebulae (PN) for which spectroscopic distances have also been determined from stellar gravities. These gravities in turn have been derived from profile

  9. Abundances of neon, sulfur, and argon in planetary nebulae

    International Nuclear Information System (INIS)

    Beck, S.C.; Lacy, J.H.; Townes, C.H.; Geballe, T.R.; Baas, F.

    1981-01-01

    Infrared observations of [Ne II], [S IV], and [Ar III] are used with optical observations to discuss the abundances of Ne, S, and Ar in 18 planetary nebulae. In addition, infrared observations of 18 other nebulae are presented. The derived abundances of S and Ar are each slightly enhanced relative to previous studies

  10. The Planetary Nebula Spectrograph : The green light for galaxy kinematics

    NARCIS (Netherlands)

    Douglas, NG; Arnaboldi, M; Freeman, KC; Kuijken, K; Merrifield, MR; Romanowsky, AJ; Taylor, K; Capaccioli, M; Axelrod, T; Gilmozzi, R; Hart, J; Bloxham, G; Jones, D

    2002-01-01

    Planetary nebulae (PNe) are now well established as probes of galaxy dynamics and as standard candles in distance determinations. Motivated by the need to improve the efficiency of planetary nebulae searches and the speed with which their radial velocities are determined, a dedicated instrument-the

  11. Early Intervention in Bipolar Disorder.

    Science.gov (United States)

    Vieta, Eduard; Salagre, Estela; Grande, Iria; Carvalho, André F; Fernandes, Brisa S; Berk, Michael; Birmaher, Boris; Tohen, Mauricio; Suppes, Trisha

    2018-05-01

    Bipolar disorder is a recurrent disorder that affects more than 1% of the world population and usually has its onset during youth. Its chronic course is associated with high rates of morbidity and mortality, making bipolar disorder one of the main causes of disability among young and working-age people. The implementation of early intervention strategies may help to change the outcome of the illness and avert potentially irreversible harm to patients with bipolar disorder, as early phases may be more responsive to treatment and may need less aggressive therapies. Early intervention in bipolar disorder is gaining momentum. Current evidence emerging from longitudinal studies indicates that parental early-onset bipolar disorder is the most consistent risk factor for bipolar disorder. Longitudinal studies also indicate that a full-blown manic episode is often preceded by a variety of prodromal symptoms, particularly subsyndromal manic symptoms, therefore supporting the existence of an at-risk state in bipolar disorder that could be targeted through early intervention. There are also identifiable risk factors that influence the course of bipolar disorder, some of them potentially modifiable. Valid biomarkers or diagnosis tools to help clinicians identify individuals at high risk of conversion to bipolar disorder are still lacking, although there are some promising early results. Pending more solid evidence on the best treatment strategy in early phases of bipolar disorder, physicians should carefully weigh the risks and benefits of each intervention. Further studies will provide the evidence needed to finish shaping the concept of early intervention. AJP AT 175 Remembering Our Past As We Envision Our Future April 1925: Interpretations of Manic-Depressive Phases Earl Bond and G.E. Partridge reviewed a number of patients with manic-depressive illness in search of a unifying endo-psychic conflict. They concluded that understanding either phase of illness was "elusive" and

  12. Novel multiple criteria decision making methods based on bipolar neutrosophic sets and bipolar neutrosophic graphs

    OpenAIRE

    Muhammad, Akram; Musavarah, Sarwar

    2016-01-01

    In this research study, we introduce the concept of bipolar neutrosophic graphs. We present the dominating and independent sets of bipolar neutrosophic graphs. We describe novel multiple criteria decision making methods based on bipolar neutrosophic sets and bipolar neutrosophic graphs. We also develop an algorithm for computing domination in bipolar neutrosophic graphs.

  13. Galactic planetary nebulae and evolution of their nuclei

    International Nuclear Information System (INIS)

    Khromov, G.S.

    1980-01-01

    The galactic system of planetary nebulae is investigated using previously constructed distance scale and kinematics data. A strong effect of observational selection is established, which has the consequence that with increasing distance, ever brighter and younger objects are observed. More accurate determinations of the spatial and surface densities of the planetary nebulae system are obtained as well as a new estimate of their total number in the Galaxy, which is approximately 200,000. New estimates are also made of the masses of the nebulae, the absolute magnitudes of the nebulae and their nuclei, and other physical parameters of these objects. The spatial and kinematic characteristics of the planetary nebulae indicate that they are objects of the old type I population. It is possible that their remote ancestors are main sequence stars of the type B8-A5-F or as yet unidentified objects of the same galactic subsystem

  14. Young planetary nebula with OH molecules - NGC 6302

    International Nuclear Information System (INIS)

    Payne, H.E.; Phillips, J.A.; Terzian, Y.

    1988-01-01

    The results of a sensitive survey of planetary nebulae in all four ground-state OH lines are reported. The results confirm that evolved planetary nebulas are not OH sources in general. However, one interesting object was not detected: an OH 1612 MHz maser in the young planetary nebula NGC 6302. This nebula may be in a brief evolutionary stage, similar to the young and compact planetary nebula Vy 2-2, where OH has already been detected. In addition, the results of further observations of NGC 6302 are reported, including VLA observations of the 1612 MHz line and continuum emission and detections of rotationally excited OH lines at 5-cm wavelength in absorption. 28 references

  15. Effects of mass and metallicity upon planetary nebula formation

    International Nuclear Information System (INIS)

    Papp, K.A.; Purton, C.R.; Kwok, S.

    1983-01-01

    We construct a parameterized function which describes the possible dependence of planetary nebula formation upon metal abundance and stellar mass. Data on galaxies in the Local Group compared with predictions made from the parameterized function indicate that heavy element abundance is the principal agent influencing the formation of planetary nebulae; stars which are rich in heavy elements are the progenitors of planetary nebulae. Our analysis, when compared with the observations, argues for a modest degree of pre-enrichment in a few of the sample galaxies. The heavy element dependence of planetary nebula formation also accounts for the deficit of planetary nebula in the nuclei of NGC 221 and NGC 224, and in the bulge of our Galaxy

  16. The effects of mass and metallicity upon planetary nebula formation

    Science.gov (United States)

    Papp, K. A.; Purton, C. R.; Kwok, S.

    1983-05-01

    A parameterized function is constructed which describes the possible dependence of planetary nebula formation upon metal abundance and stellar mass. Data on galaxies in the Local Group compared with predictions made from the parameterized function indicate that heavy element abundance is the principal agent influencing the formation of planetary nebulae; stars which are rich in heavy elements are the progenitors of planetary nebulae. This analysis, when compared with the observations, argues for a modest degree of pre-enrichment in a few of the sample galaxies. The heavy element dependence of planetary nebula formation also accounts for the deficit of planetary nebulae in the nuclei of NGC 221 and NGC 224, and in the bulge of our Galaxy.

  17. Aerodynamics of solid bodies in the solar nebula

    Energy Technology Data Exchange (ETDEWEB)

    Weidenschilling, S J [Carnegie Institution of Washington, D.C. (USA). Dept. of Terrestrial Magnetism

    1977-07-01

    On a centrally condensed solar nebula, the pressure gradient in the gas causes the nebula to rotate more slowly than the free orbital velocity. Drag forces cause the orbits of solid bodies to decay. Their motions have been investigated analytically and numerically for all applicable drag laws. The maximum radial velocity developed is independent of the drag law, and insensitive to the nebular mass. Results are presented for a variety of model nebulae. Radial velocities depend strongly on particle size, reaching values of the order of 10/sup 4/ cm/s for metre-sized objects. Possible consequences include: mixing of solid matter with the solar nebula on short timescales, collisions leading to rapid accumulation of planetesimals, fractionation of bodies by size or density, and production of regions of anomalous composition in the solar nebula.

  18. Relation between radius and expansion velocity in planetary nebulae

    International Nuclear Information System (INIS)

    Chu, Y.H.; Kwitter, K.B.; Kaler, J.B.

    1984-01-01

    The expansion velocity-radius (R-V) relation for planetary nebulae is examined using the existing measurements of expansion velocities and recent calculations of radii. It is found that some of the previously alleged R-V relations for PN are not convincingly established. The scatter in the R-V plots may be due largely to stratification of ions in individual nebulae and to heterogeneity in the planetary nebula population. In addition, from new echelle/CCD observations of planetary nebulae, it is found that spatial information is essential in deriving the internal kinematic properties. Future investigations of R-V relations should be pursued separately for groups of planetaries with similar physical properties, and they should employ observations of appropriate low excitation lines in order to measure the expansion velocity at the surface of the nebula. 26 references

  19. A large bubble around the Crab Nebula

    Science.gov (United States)

    Romani, Roger W.; Reach, William T.; Koo, Bon Chul; Heiles, Carl

    1990-01-01

    IRAS and 21 cm observations of the interstellar medium around the Crab nebula show evidence of a large bubble surrounded by a partial shell. If located at the canonical 2 kpc distance of the Crab pulsar, the shell is estimated to have a radius of about 90 pc and to contain about 50,000 solar masses of swept-up gas. The way in which interior conditions of this bubble can have important implications for observations of the Crab are described, and the fashion in which presupernova evolution of the pulsar progenitor has affected its local environment is described.

  20. Electrodynamic coupling between pulsars and surrounding nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Dobrowolny, M [Consiglio Nazionale delle Ricerche, Frascati (Italy). Lab. per il Plasma nello Spazio; L' Aquila Univ. (Italy). Istituto di Fisica); Ferrari, A [Cambridge Univ. (UK). Inst. of Astronomy; Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Turin Univ. (Italy). Istituto di Fisica)

    1976-02-01

    In this work a study is presented of collective plasma processes by which pulsars can energetically support young supernova remnants. We show that many of the observed features of the Crab Nebula can be adequately interpreted in terms of a parametric interaction between the low-frequency electromagnetic wave emitted by the pulsar in the oblique rotator model and a relativistic wind of charged particle leaking from the pulsar's inner magnetosphere. In particular we show that there is a relativistic parametric resonant coupling of the strong wave with electrostatic and electromagnetic modes.

  1. ELEMENT MASSES IN THE CRAB NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    Sibley, Adam R.; Katz, Andrea M.; Satterfield, Timothy J.; Vanderveer, Steven J.; MacAlpine, Gordon M. [Department of Physics and Astronomy, Trinity University, San Antonio, TX 78212 (United States)

    2016-10-01

    Using our previously published element abundance or mass-fraction distributions in the Crab Nebula, we derived actual mass distributions and estimates for overall nebular masses of hydrogen, helium, carbon, nitrogen, oxygen and sulfur. As with the previous work, computations were carried out for photoionization models involving constant hydrogen density and also constant nuclear density. In addition, employing new flux measurements for [Ni ii]  λ 7378, along with combined photoionization models and analytic computations, a nickel abundance distribution was mapped and a nebular stable nickel mass estimate was derived.

  2. Planetary nebulae and the interstellar medium

    Science.gov (United States)

    Aller, L. H.

    1986-01-01

    In addition to available published data on planetary nebulae (PN), some 40 objects largely concentrated towards the galactic center and anticenter regions were included. All were observed with the Lick 3(sup m) telescope and image tube scanner. Abundances of C, N, O, Ne, Cl, and Ar were determined by a procedure in which theoretical models were used to obtain ionization correction factors (ICF). Of the 106 PN, 66 are N-rich and 40 are N-poor. There appear to be no significant differences between the average compositions in the solar neighborhood and the average taken over the entire observable portion of the galaxy.

  3. Orion infrared nebula/molecular cloud

    International Nuclear Information System (INIS)

    Zuckerman, B.; Palmer, P.

    1975-01-01

    Observational and theoretical studies of the Orion Nebula and the associated molecular clouds have greatly increased our understanding of this and other regions in which star formation is taking place. Fundamental questions remain unanswered; and in this Letter we address three of them: (1) the chemical composition of the molecular cloud, (2) its internal motions, and (3) the role of magnetic fields in its evolution. We show that the gas phase chemistry and internal motions in one part of the cloud are distinctly different from those in the rest of the cloud, and two recent estimates of the magnetic field strengths are very uncertain. (auth)

  4. Bipolar pulse forming line

    Science.gov (United States)

    Rhodes, Mark A.

    2008-10-21

    A bipolar pulse forming transmission line module for linear induction accelerators having first, second, third, fourth, and fifth planar conductors which form an interleaved stack with dielectric layers between the conductors. Each conductor has a first end, and a second end adjacent an acceleration axis. The first and second planar conductors are connected to each other at the second ends, the fourth and fifth planar conductors are connected to each other at the second ends, and the first and fifth planar conductors are connected to each other at the first ends via a shorting plate adjacent the first ends. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short a high voltage from the first end of the third planar conductor to the first end of the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  5. On planetary nebulae as sources of carbon dust: Infrared emission from planetary nebulae of the galactic halo

    International Nuclear Information System (INIS)

    Dinerstein, H.L.; Lester, D.F.

    1990-01-01

    Researchers examine here the characteristics of the infrared emission from the four planetary nebulae which are believed on the basis of their low overall metallicities to belong to the halo population. These nebulae are of particular interest because they are the most metal-poor ionized nebulae known in our Galaxy, and offer the opportunity to probe possible dependences of the dust properties on nebular composition. Researchers present fluxes extracted from co-addition of the IRAS data, as well as ground-based near infrared measurements. Each of the four halo objects, including the planetary nebula in the globular cluster M15, is detected in at least one infrared band. Researchers compare the estimated infrared excesses of these nebulae (IRE, the ratio of measured infrared power to the power available in the form of resonantly-trapped Lyman alpha photons) to those of disk planetary nebulae with similar densities but more normal abundances. Three of the halo planetaries have IRE values similar to those of the disk nebulae, despite the fact that their Fe- and Si-peak gas phase abundances are factors of 10 to 100 lower. However, these halo nebulae have normal or elevated C/H ratios, due to nuclear processing and mixing in their red giant progenitors. Unlike the other halo planetaries, DDDM1 is deficient in carbon as well as in the other light metals. This nebula has a substantially lower IRE than the other halo planetaries, and may be truly dust efficient. Researchers suggest that the deficiency is due to a lack of the raw material for producing carbon-based grains, and that the main bulk constituent of the dust in these planetary nebulae is carbon

  6. Confronting Standard Models of Proto-planetary Disks with New Mid-infrared Sizes from the Keck Interferometer

    Science.gov (United States)

    Millan-Gabet, Rafael; Che, Xiao; Monnier, John D.; Sitko, Michael L.; Russell, Ray W.; Grady, Carol A.; Day, Amanda N.; Perry, R. B.; Harries, Tim J.; Aarnio, Alicia N.; Colavita, Mark M.; Wizinowich, Peter L.; Ragland, Sam; Woillez, Julien

    2016-08-01

    We present near- and mid-infrared (MIR) interferometric observations made with the Keck Interferometer Nuller and near-contemporaneous spectro-photometry from the infrared telescope facilities (IRTFs) of 11 well-known young stellar objects, several of which were observed for the first time in these spectral and spatial resolution regimes. With au-level spatial resolution, we first establish characteristic sizes of the infrared emission using a simple geometrical model consisting of a hot inner rim and MIR disk emission. We find a high degree of correlation between the stellar luminosity and the MIR disk sizes after using near-infrared data to remove the contribution from the inner rim. We then use a semi-analytical physical model to also find that the very widely used “star + inner dust rim + flared disk” class of models strongly fails to reproduce the spectral energy distribution (SED) and spatially resolved MIR data simultaneously; specifically a more compact source of MIR emission is required than results from the standard flared disk model. We explore the viability of a modification to the model whereby a second dust rim containing smaller dust grains is added, and find that the 2-rim model leads to significantly improved fits in most cases. This complexity is largely missed when carrying out SED modeling alone, although detailed silicate feature fitting by McClure et al. recently came to a similar conclusion. As has been suggested recently by Menu et al., the difficulty in predicting MIR sizes from the SED alone might hint at “transition disk”-like gaps in the inner au; however, the relatively high correlation found in our MIR disk size versus stellar luminosity relation favors layered disk morphologies and points to missing disk model ingredients instead.

  7. Confronting Standard Models of Proto-planetary Disks with New Mid-infrared Sizes from the Keck Interferometer

    OpenAIRE

    Millan-Gabet, Rafael; Che, Xiao; Monnier, John D.; Sitko, Michael L.; Russell, Ray W.; Grady, Carol A.; Day, Amanda N.; Perry, R. B.; Harries, Tim J.; Aarnio, Alicia N.; Colavita, Mark M.; Wizinowich, Peter L.; Ragland, Sam; Woillez, Julien

    2016-01-01

    We present near- and mid-infrared (MIR) interferometric observations made with the Keck Interferometer Nuller and near-contemporaneous spectro-photometry from the infrared telescope facilities (IRTFs) of 11 well-known young stellar objects, several of which were observed for the first time in these spectral and spatial resolution regimes. With au-level spatial resolution, we first establish characteristic sizes of the infrared emission using a simple geometrical model consisting of a hot inne...

  8. CONFRONTING STANDARD MODELS OF PROTO-PLANETARY DISKS WITH NEW MID-INFRARED SIZES FROM THE KECK INTERFEROMETER

    Energy Technology Data Exchange (ETDEWEB)

    Millan-Gabet, Rafael [California Institute of Technology, NASA Exoplanet Science Institute, Pasadena, CA 91125 (United States); Che, Xiao; Monnier, John D.; Aarnio, Alicia N. [University of Michigan Astronomy Department, 1085 S. University Avenue 303B West Hall University of Michigan, Ann Arbor, MI 48109-1107 (United States); Sitko, Michael L.; Day, Amanda N. [Department of Physics, University of Cincinnati, Cincinnati OH 45221 (United States); Russell, Ray W. [The Aerospace Corporation, Los Angeles, CA 90009 (United States); Grady, Carol A. [Eureka Scientific, 2452 Delmer, Suite 100, Oakland, CA 96002 (United States); Perry, R. B. [NASA Langley Research Center, MS 160, Hampton, VA 23681 (United States); Harries, Tim J. [Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Colavita, Mark M. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Wizinowich, Peter L.; Ragland, Sam; Woillez, Julien, E-mail: R.Millan-Gabet@caltech.edu [Keck Observatory, 65-1120 Mamalahoa Hwy, Kamuela, HI 96743 (United States)

    2016-08-01

    We present near- and mid-infrared (MIR) interferometric observations made with the Keck Interferometer Nuller and near-contemporaneous spectro-photometry from the infrared telescope facilities (IRTFs) of 11 well-known young stellar objects, several of which were observed for the first time in these spectral and spatial resolution regimes. With au-level spatial resolution, we first establish characteristic sizes of the infrared emission using a simple geometrical model consisting of a hot inner rim and MIR disk emission. We find a high degree of correlation between the stellar luminosity and the MIR disk sizes after using near-infrared data to remove the contribution from the inner rim. We then use a semi-analytical physical model to also find that the very widely used “star + inner dust rim + flared disk” class of models strongly fails to reproduce the spectral energy distribution (SED) and spatially resolved MIR data simultaneously; specifically a more compact source of MIR emission is required than results from the standard flared disk model. We explore the viability of a modification to the model whereby a second dust rim containing smaller dust grains is added, and find that the 2-rim model leads to significantly improved fits in most cases. This complexity is largely missed when carrying out SED modeling alone, although detailed silicate feature fitting by McClure et al. recently came to a similar conclusion. As has been suggested recently by Menu et al., the difficulty in predicting MIR sizes from the SED alone might hint at “transition disk”-like gaps in the inner au; however, the relatively high correlation found in our MIR disk size versus stellar luminosity relation favors layered disk morphologies and points to missing disk model ingredients instead.

  9. CONFRONTING STANDARD MODELS OF PROTO-PLANETARY DISKS WITH NEW MID-INFRARED SIZES FROM THE KECK INTERFEROMETER

    International Nuclear Information System (INIS)

    Millan-Gabet, Rafael; Che, Xiao; Monnier, John D.; Aarnio, Alicia N.; Sitko, Michael L.; Day, Amanda N.; Russell, Ray W.; Grady, Carol A.; Perry, R. B.; Harries, Tim J.; Colavita, Mark M.; Wizinowich, Peter L.; Ragland, Sam; Woillez, Julien

    2016-01-01

    We present near- and mid-infrared (MIR) interferometric observations made with the Keck Interferometer Nuller and near-contemporaneous spectro-photometry from the infrared telescope facilities (IRTFs) of 11 well-known young stellar objects, several of which were observed for the first time in these spectral and spatial resolution regimes. With au-level spatial resolution, we first establish characteristic sizes of the infrared emission using a simple geometrical model consisting of a hot inner rim and MIR disk emission. We find a high degree of correlation between the stellar luminosity and the MIR disk sizes after using near-infrared data to remove the contribution from the inner rim. We then use a semi-analytical physical model to also find that the very widely used “star + inner dust rim + flared disk” class of models strongly fails to reproduce the spectral energy distribution (SED) and spatially resolved MIR data simultaneously; specifically a more compact source of MIR emission is required than results from the standard flared disk model. We explore the viability of a modification to the model whereby a second dust rim containing smaller dust grains is added, and find that the 2-rim model leads to significantly improved fits in most cases. This complexity is largely missed when carrying out SED modeling alone, although detailed silicate feature fitting by McClure et al. recently came to a similar conclusion. As has been suggested recently by Menu et al., the difficulty in predicting MIR sizes from the SED alone might hint at “transition disk”-like gaps in the inner au; however, the relatively high correlation found in our MIR disk size versus stellar luminosity relation favors layered disk morphologies and points to missing disk model ingredients instead.

  10. Physics and chemistry of the solar nebula.

    Science.gov (United States)

    Lunine, J I

    1997-06-01

    The solar system is thought to have begun in a flattened disk of gas and dust referred to traditionally as the solar nebula. Such a construct seems to be a natural product of the collapse of dense parts of giant molecular clouds, the vast star-forming regions that pepper the Milky Way and other galaxies. Gravitational, magnetic and thermal forces within the solar nebula forced a gradual evolution of mass toward the center (where the sun formed) and angular momentum (borne by a small fraction of the mass) toward the outer more distant regions of the disk. This evolution was accompanied by heating and a strong temperature contrast from the hot, inner regions to the cold, more remote parts of the disk. The resulting chemistry in the disk determined the initial distribution of organic matter in the planets; most of the reduced carbon species, in condensed form, were located beyond the asteroid belt (the 'outer' solar system). The Earth could have received much of its inventory of pre-biological material from comets and other icy fragments of the process of planetary formation in the outer solar system.

  11. Dark nebulae, dark lanes, and dust belts

    CERN Document Server

    Cooke, Antony

    2012-01-01

    As probably the only book of its type, this work is aimed at the observer who wants to spend time with something less conventional than the usual fare. Because we usually see objects in space by means of illumination of one kind or another, it has become routine to see them only in these terms. However, part of almost everything that we see is the defining dimension of dark shading, or even the complete obscuration of entire regions in space. Thus this book is focused on everything dark in space: those dark voids in the stellar fabric that mystified astronomers of old; the dark lanes reported in many star clusters; the magical dust belts or dusty regions that have given so many galaxies their identities; the great swirling 'folds' that we associate with bright nebulae; the small dark feature detectable even in some planetary nebulae; and more. Many observers pay scant attention to dark objects and details. Perhaps they are insufficiently aware of them or of the viewing potential they hold, but also it may be...

  12. Asenapine for bipolar disorder

    Directory of Open Access Journals (Sweden)

    Scheidemantel T

    2015-12-01

    Full Text Available Thomas Scheidemantel,1 Irina Korobkova,2 Soham Rej,3,4 Martha Sajatovic1,2 1University Hospitals Case Medical Center, 2Case Western Reserve University School of Medicine, Cleveland, OH, USA; 3Department of Psychiatry, University of Toronto, Toronto, ON, 4Geri PARTy Research Group, Jewish General Hospital, Montreal, QC, Canada Abstract: Asenapine (Saphris® is an atypical antipsychotic drug which has been approved by the US Food and Drug Administration for the treatment of schizophrenia in adults, as well as the treatment of acute manic or mixed episodes of bipolar I in both adult and pediatric populations. Asenapine is a tetracyclic drug with antidopaminergic and antiserotonergic activity with a unique sublingual route of administration. In this review, we examine and summarize the available literature on the safety, efficacy, and tolerability of asenapine in the treatment of bipolar disorder (BD. Data from randomized, double-blind trials comparing asenapine to placebo or olanzapine in the treatment of acute manic or mixed episodes showed asenapine to be an effective monotherapy treatment in clinical settings; asenapine outperformed placebo and showed noninferior performance to olanzapine based on improvement in the Young Mania Rating Scale scores. There are limited data available on the use of asenapine in the treatment of depressive symptoms of BD, or in the maintenance phase of BD. The available data are inconclusive, suggesting the need for more robust data from prospective trials in these clinical domains. The most commonly reported adverse effect associated with use of asenapine is somnolence. However, the somnolence associated with asenapine use did not cause significant rates of discontinuation. While asenapine was associated with weight gain when compared to placebo, it appeared to be modest when compared to other atypical antipsychotics, and its propensity to cause increases in hemoglobin A1c or serum lipid levels appeared to be

  13. Spectrophotometry of ring nebulae around Wolf-Rayet stars

    International Nuclear Information System (INIS)

    Kwitter, K.B.

    1979-01-01

    Spectrophotometric observations of four ring nebulae surrounding population I Wolf-Rayet (WN) stars have been obtained, and four additional filamentary nebulae in order to determine the physical conditions and chemical abundances in these objects. It was concluded that the ring nebulae are enriched in nitrogen and helium as a result of contamination of the ambient interstellar medium by the helium- and nitrogen-rich wind from the central Wolf-Rayet star. Of the additional nebulae studied, two were found to be Peimbert Type I planetary nebulae, overabundant in nitrogen and helium due to mixing of CNO processed material into the parent envelope prior to ejection. One of the remaining objects, a shell around an Oef star, is found to have normal abundances; the other, a small H II region around an early Be star, also exhibits normal abundances. It was attempted to interpret the ring nebulae and the Oef shell as interstellar bubbles, according to recent theory; it met with varying degrees of success. For two of the ring nebulae, the fraction of nebular mass contributed by the central star can be estimated from published stellar abundances. It was found that in these two cases, the stellar wind has provided less than 10% of the observed nebular mass

  14. C2 emission features in the Red Rectangle : A combined observational laboratory study

    NARCIS (Netherlands)

    Wehres, N.; Romanzin, C.; Linnartz, H.; van Winckel, H.; Tielens, A. G. G. M.

    Context. The Red Rectangle proto-planetary nebula (HD 44179) is known for a number of rather narrow emission features superimposed on a broad extended red emission (ERE) covering the 5000-7500 angstrom regime. The origin of these emission features is unknown. Aims. The aim of the present work is to

  15. Induced massive star formation in the trifid nebula?

    Science.gov (United States)

    Cernicharo; Lefloch; Cox; Cesarsky; Esteban; Yusef-Zadeh; Mendez; Acosta-Pulido; Garcia Lopez RJ; Heras

    1998-10-16

    The Trifid nebula is a young (10(5) years) galactic HII region where several protostellar sources have been detected with the infrared space observatory. The sources are massive (17 to 60 solar masses) and are associated with molecular gas condensations at the edges or inside the nebula. They appear to be in an early evolutionary stage and may represent the most recent generation of stars in the Trifid. These sources range from dense, apparently still inactive cores to more evolved sources, undergoing violent mass ejection episodes, including a source that powers an optical jet. These observations suggest that the protostellar sources may have evolved by induced star formation in the Trifid nebula.

  16. X-ray Emission from the Guitar Nebula

    OpenAIRE

    Romani, Roger W.; Cordes, James M.; Yadigaroglu, I. -A.

    1997-01-01

    We have detected weak soft X-ray emission from the Pulsar Wind Nebula trailing the high velocity star PSR 2224+65 (the `Guitar Nebula'). This X-ray flux gives evidence of \\gamma~10^7 eV particles in the pulsar wind and constrains the properties of the post-shock flow. The X-ray emission is most easily understood if the shocked pulsar wind is partly confined in the nebula and if magnetic fields in this zone can grow to near equipartition values.

  17. X-Ray Emission from the Guitar Nebula

    Science.gov (United States)

    Romani, Roger W.; Cordes, James M.; Yadigaroglu, I.-A.

    1997-01-01

    We have detected weak soft X-ray emission from the pulsar wind nebula trailing the high-velocity star PSR 2224+65 (the "Guitar Nebula"). This X-ray flux gives evidence of gamma approximately 10(exp 7) eV particles in the pulsar wind and constrains the properties of the postshock flow. The X-ray emission is most easily understood if the shocked pulsar wind is partly confined in the nebula and if magnetic fields in this zone can grow to near-equipartition values.

  18. Modeling suicide in bipolar disorders.

    Science.gov (United States)

    Malhi, Gin S; Outhred, Tim; Das, Pritha; Morris, Grace; Hamilton, Amber; Mannie, Zola

    2018-02-19

    Suicide is a multicausal human behavior, with devastating and immensely distressing consequences. Its prevalence is estimated to be 20-30 times greater in patients with bipolar disorders than in the general population. The burden of suicide and its high prevalence in bipolar disorders make it imperative that our current understanding be improved to facilitate prediction of suicide and its prevention. In this review, we provide a new perspective on the process of suicide in bipolar disorder, in the form of a novel integrated model that is derived from extant knowledge and recent evidence. A literature search of articles on suicide in bipolar disorder was conducted in recognized databases such as Scopus, PubMed, and PsycINFO using the keywords "suicide", "suicide in bipolar disorders", "suicide process", "suicide risk", "neurobiology of suicide" and "suicide models". Bibliographies of identified articles were further scrutinized for papers and book chapters of relevance. Risk factors for suicide in bipolar disorders are well described, and provide a basis for a framework of epigenetic mechanisms, moderated by neurobiological substrates, neurocognitive functioning, and social inferences within the environment. Relevant models and theories include the diathesis-stress model, the bipolar model of suicide and the ideation-to-action models, the interpersonal theory of suicide, the integrated motivational-volitional model, and the three-step theory. Together, these models provide a basis for the generation of an integrated model that illuminates the suicidal process, from ideation to action. Suicide is complex, and it is evident that a multidimensional and integrated approach is required to reduce its prevalence. The proposed model exposes and provides access to components of the suicide process that are potentially measurable and may serve as novel and specific therapeutic targets for interventions in the context of bipolar disorder. Thus, this model is useful not only

  19. Bipolar explosion models for hypernovae

    International Nuclear Information System (INIS)

    Maeda, Keiichi; Nomoto, Ken'ichi

    2003-01-01

    Bipolar explosion models for hypernovae (very energetic supernovae) are presented. These models provide a favorable situation to explain some unexpected features in observations of hypernovae, e.g., high velocity matter dominated by Fe and low velocity matter dominated by O. The overall abundance of these models gives a good fit, at least qualitatively, to abundances in extremely metal-poor stars. We suggest hypernovae be driven by bipolar jets and contribute significantly to the early Galactic chemical evolution

  20. Functional remediation for bipolar disorder

    OpenAIRE

    Martínez-Arán, Anabel, 1971-; Torrent, C.; Solé, B.; Bonnín, C.M.; Rosa, A.R.; Sánchez-Moreno, J.; Vieta i Pascual, Eduard, 1963-

    2014-01-01

    Neurocognitive impairment constitutes a core feature of bipolar illness. The main domains affected are verbal memory, attention, and executive functions. Deficits in these areas as well as difficulties to get functional remission seem to be increased associated with illness progression. Several studies have found a strong relationship between neurocognitive impairment and low functioning in bipolar disorder, as previously reported in other illnesses such as schizophrenia. Cognitive remediatio...

  1. The emerging planetary nebula CRL 618 and its unsettled central star(s)

    Energy Technology Data Exchange (ETDEWEB)

    Balick, B. [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Riera, A. [Departament de Física I Enginyeria Nuclear, EUETIB, Universitat Politècnica de Catalunya, Comte d' Urgell 187, E-08036 Barcelona (Spain); Raga, A.; Velázquez, P. F. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, 04510 D.F. (Mexico); Kwitter, K. B., E-mail: balick@uw.edu, E-mail: angels.riera@upc.edu, E-mail: raga@nucleares.unam.mx, E-mail: pablo@nucleares.unam.mx, E-mail: kkwitter@williams.edu [Department of Astronomy, Williams College, Williamstown, MA 01267 (United States)

    2014-11-01

    We report deep long-slit emission-line spectra, the line flux ratios, and Doppler profile shapes of various bright optical lines. The low-ionization lines (primarily [N I], [O I], [S II], and [N II]) originate in shocked knots, as reported by many previous observers. Dust-scattered lines of higher ionization are seen throughout the lobes but do not peak in the knots. Our analysis of these line profiles and the readily discernible stellar continuum shows that (1) the central star is an active symbiotic (whose spectrum resembles the central stars of highly bipolar and young planetary nebulae such as M2-9 and Hen2-437) whose compact companion shows a WC8-type spectrum, (2) extended nebular lines of [O III] and He I originate in the heavily obscured nuclear H II region, and (3) the Balmer lines observed throughout the lobes are dominated by reflected Hα emission from the symbiotic star. Comparing our line ratios with those observed historically shows that (1) the [O III]/Hβ and He I/Hβ ratios have been steadily rising by large amounts throughout the nebula, (2) the Hα/Hβ ratio is steadily decreasing while Hγ/Hβ remains nearly constant, and (3) the low-ionization line ratios formed in the shocked knots have been in decline in different ways at various locations. We show that the first two of these results might be expected if the symbiotic central star has been active and if its bright Hα line has faded significantly in the past 20 years.

  2. New Identifications of the CCH Radical in Planetary Nebulae: A Connection to C60?

    Science.gov (United States)

    Schmidt, D. R.; Ziurys, L. M.

    2017-12-01

    New detections of CCH have been made toward nine planetary nebulae (PNe), including K4-47, K3-58, K3-17, M3-28, and M4-14. Measurements of the N = 1 → 0 and N = 3 → 2 transitions of this radical near 87 and 262 GHz were carried out using the new 12 m and the Sub-Millimeter Telescope (SMT) of the Arizona Radio Observatory (ARO). The presence of fine and/or hyperfine structure in the spectra aided in the identification. CCH was not observed in two PNe which are sources of C60. The planetary nebulae with positive detections represent a wide range of ages and morphologies, and all had previously been observed in HCN and HNC. Column densities for CCH in the PNe, determined from radiative transfer modeling, were N tot(CCH) ˜ 0.2-3.3 × 1015 cm-2, corresponding to fractional abundances with respect to H2 of f ˜ 0.2-47 × 10-7. The abundance of CCH was found to not vary significantly with kinematic age across a time span of ˜10,000 years, in contrast to predictions of chemical models. CCH appears to be a fairly common constituent of PNe that are carbon-rich, and its distribution may anti-correlate with that of C60. These results suggest that CCH may be a product of C60 photodestruction, which is known to create C2 units. The molecule may subsequently survive the PN stage and populate diffuse clouds. The distinct, double-horned line profiles for CCH observed in K3-45 and M3-28 indicate the possible presence of a bipolar flow oriented at least partially toward the line of sight.

  3. An investigation of the Carina Nebula

    Science.gov (United States)

    Brooks, Kate J.

    2000-10-01

    It is well known that the radiation fields and stellar winds of massive stars can drastically affect the physical conditions, structure and chemistry of the giant molecular cloud (GMC) from which they formed. It is also thought that massive stars are at least partly responsible for triggering further star formation within a GMC. The details of this interaction, however, are not well understood and additional detailed study of massive star-forming regions is needed. This study has focused on a multi-wavelength investigation of the Carina Nebula. This is a spectacular massive star-forming region that contains two of the most massive star clusters in our galaxy, Trumpler 14 and Trumpler 16, and one of the most massive stars known -- η Car. The goal of this study has been to obtain information on the molecular gas, ionized gas and photodissociation regions (PDRs) from a collection of instruments which have the highest angular resolution and sensitivity available to date. The Mopra Telescope and the Swedish-ESO Submillimeter Telescope (SEST) were used to obtain a series of molecular line observations of the GMC between 150 and 230 GHz. Observations of H110α recombination-line emission at 4.874 GHz and the related continuum emission were obtained with the Australia Telescope Compact Array and used to study the ionized gas associated with the two HII regions, Car I and Car II. H2 1--0 S(1) (2.12 microns) and Brγ (2.16 microns) observations using the University of New South Wales Infrared Fabry-Perot (UNSWIRF) and 3.29 micron narrow-band observations obtained with the SPIREX/Abu thermal infrared camera were used to study the PDRs on the surface of molecular clumps in the Keyhole region, a dark optical feature in the vicinity of η Car. The results of these observations provide detailed information on the excitation conditions, kinematics and morphology of regions within the HII region/molecular cloud complex of the Carina Nebula. In addition, the results confirm that

  4. Chemical enrichment in halo planetary nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Peimbert, S; Rayo, J F; Peimbert, M [Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Astronomia

    1981-01-01

    Photoelectric spectrophotometry of emission lines in the 3400-7400 A region is presented for the planetary nebulae 108-76/sup 0/1(BB1). From these observations the relative abundances of H, He, C, N, O and Ne are derived. The abundances of the halo PN (BB1, H4-1 and K648) are compared to those predicted by stellar evolution theory under the assumption that the envelope has the chemical composition of the matter located between the H burning shell and the surface. The observed He/H and C/O values are higher than predicted which implies that halo PN contain matter from deeper layers than the H burning shell. Furthermore, the O/Ar, N/Ar and Ne/Ar values in halo PN are higher than in the solar neighbourhood, at least part of this enrichment is produced by the PN progenitors.

  5. The Helix Nebula Viewed in HCO+: Large-scale Mapping of the J = 1 → 0 Transition

    Science.gov (United States)

    Zeigler, N. R.; Zack, L. N.; Woolf, N. J.; Ziurys, L. M.

    2013-11-01

    The J = 1 → 0 transition of HCO+ at 89 GHz has been mapped across the Helix Nebula (NGC 7293) with 70'' spatial resolution (1.68 km s-1 velocity resolution) using the Arizona Radio Observatory 12 m telescope. This work is the first large-scale mapping project of a dense gas tracer (n(H2) ~ 105 cm-3) in old planetary nebulae. Observations of over 200 positions encompassing the classical optical image were conducted with a 3σ noise level of ~20 mK. HCO+ was detected at most positions, often exhibiting multiple velocity components indicative of complex kinematic structures in dense gas. The HCO+ spectra suggest that the Helix is composed of a bipolar, barrel-like structure with red- and blue-shifted halves, symmetric with respect to the central star and oriented ~10° east from the line of sight. A second bipolar, higher velocity outflow exists as well, situated along the direction of the Helix "plumes." The column density of HCO+ across the Helix is N tot ~ 1.5 × 1010-5.0 × 1011 cm-2, with an average value N ave ~ 1 × 1011 cm-2, corresponding to an abundance, relative to H2, of f ~ 1.4 × 10-8. This value is similar to that observed in young PN, and contradicts chemical models, which predict that the abundance of HCO+ decreases with nebular age. This study indicates that polyatomic molecules readily survive the ultraviolet field of the central white dwarf, and can be useful in tracing nebular morphology in the very late stages of stellar evolution.

  6. Distinguishing between symbiotic stars and planetary nebulae

    Science.gov (United States)

    Iłkiewicz, K.; Mikołajewska, J.

    2017-10-01

    Context. The number of known symbiotic stars (SySt) is still significantly lower than their predicted population. One of the main problems in finding the total population of SySt is the fact that their spectrum can be confused with other objects, such as planetary nebulae (PNe) or dense H II regions. This problem is reinforced by the fact that in a significant fraction of established SySt the emission lines used to distinguish them from other objects are not present. Aims: We aim at finding new diagnostic diagrams that could help separate SySt from PNe. Additionally, we examine a known sample of extragalactic PNe for candidate SySt. Methods: We employed emission line fluxes of known SySt and PNe from the literature. Results: We found that among the forbidden lines in the optical region of spectrum, only the [O III] and [N II] lines can be used as a tool for distinguishing between SySt and PNe, which is consistent with the fact that they have the highest critical densities. The most useful diagnostic that we propose is based on He I lines, which are more common and stronger in SySt than forbidden lines. All these useful diagnostic diagrams are electron density indicators that better distinguish PNe and ionized symbiotic nebulae. Moreover, we found six new candidate SySt in the Large Magellanic Cloud and one in M 81. If confirmed, the candidate in M 81 would be the farthest known SySt thus far.

  7. Quetiapine monotherapy for bipolar depression

    Directory of Open Access Journals (Sweden)

    Michael E Thase

    2008-03-01

    Full Text Available Michael E ThaseDepartments of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA, USA; the Philadelphia Veterans Affairs Medical Center, Philadelphia, PA, USA; and the University of Pittsburgh Medical Center, Pittsburgh, PA, USAAbstract: Bipolar depression is more common, disabling, and difficult-to-treat than the manic and hypomanic phases that define bipolar disorder. Unlike the treatment of so-called “unipolar” depressions, antidepressants generally are not indicated as monotherapies for bipolar depressions and recent studies suggest that - even when used in combination with traditional mood stabilizers – antidepressants may have questionable value for bipolar depression. The current practice is that mood stabilizers are initiated first as monotherapies; however, the antidepressant efficacy of lithium and valproate is modest at best. Within this context the role of atypical antipsychotics is being evaluated. The combination of olanzapine and the antidepressant fluoxetine was the first treatment to receive regulatory approval in the US specifically for bipolar I depression. Quetiapine was the second medication to be approved for this indication, largely as the result of two pivotal trials known by the acronyms of BOLDER (BipOLar DEpRession I and II. Both studies demonstrated that two doses of quetiapine (300 mg and 600 mg given once daily at bedtime were significantly more effective than placebo, with no increased risk of patients switching into mania. Pooling the two studies, quetiapine was effective for both bipolar I and bipolar II depressions and for patients with (and without a history of rapid cycling. The two doses were comparably effective in both studies. Although the efficacy of quetiapine monotherapy has been established, much additional research is necessary. Further studies are needed to more fully investigate dose-response relationships and comparing quetiapine monotherapy to other mood stabilizers

  8. The Coldest Object in the Universe: Probing the Mass Distribution of the Ultra-Cold Outflow and Dusty Disk in the Boomerang Nebula

    Science.gov (United States)

    Sahai, R.; Vlemmings, W.; Nyman, L.

    2015-12-01

    Our Cycle 0 ALMA observations confirmed that the Boomerang Nebula is the coldest known object in the Universe, with a massive high-speed outflow that has cooled significantly below the temperature of the cosmic background (CMB). The Boomerang's prodigious mass-loss rate (0.001M⊙) and low-luminosity (300L⊙) make it a key object for understanding the remarkable transition of the circumstellar envelopes of AGB stars into bipolar planetary nebulae. We have obtained new ACA CO 1-0 data that recover much of the flux lost in the Cycle 0 data, and reveal heretofore unseen distant regions of the ultra-cold outflow re-heated to temperatures above the CMB. Our CO J=3-2 data reveal the precise, highly collimated shape of an inner bipolar structure and its dense central waist, with unprecedented angular resolution (0.4”). The waist shows a core-halo structure in the thermal dust emission at 0.88 mm, and its derived flux at this wavelength, compared with the 3.3, 2.6, and 1.3 mm fluxes support the presence of about 5×10-4 M⊙ of very large (˜mm-sized), cold (˜30K) grains. We also find the unexpected presence of weak SO emission, possibly resulting from the release of S from grains due to high-speed shocks.

  9. The Coldest Object in the Universe: Probing the Mass Distribution of the Ultra-Cold Outflow and Dusty Disk in the Boomerang Nebula

    Science.gov (United States)

    Sahai, R.; Vlemmings, W.; Nyman, L. A.

    2014-01-01

    Our Cycle 0 ALMA observations confirmed that the Boomerang Nebula is the coldest known object in the universe, with a massive high-speed outflow that has cooled significantly below the temperature of the cosmic background (CMB). The Boomerang's prodigious mass-loss rate (0.001 solar mass M yr (exp -1) and low-luminosity (300L ) make it a key object for understanding the remarkable transition of the circumstellar envelopes of AGB stars into bipolar planetary nebulae. We have obtained new ACA CO 1-0 data that recover much of the flux lost in the Cycle O data, and reveal heretofore unseen distant regions of the ultra-cold outflow reheated to temperatures above the CMB. Our CO J=3-2 data reveal the precise, highly collimated shape of an inner bipolar structure and its dense central waist, with unprecedented angular resolution (0.4 in). The waist shows a core-halo structure in the thermal dust emission at 0.88 millimeter, and its derived flux at this wavelength, compared with the 3.3, 2.6, and 1.3 millimeter fluxes support the presence of about 5 x 10 (exp -4) solar mass of very large (approximately millimeter-sized), cold (approximately 30K) grains. We also find the unexpected presence of weak SO emission, possibly resulting from the release of S from grains due to high-speed shocks.

  10. SULFUR- AND SILICON-BEARING MOLECULES IN PLANETARY NEBULAE: THE CASE OF M2-48

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, J. L.; Ziurys, L. M., E-mail: lziurys@email.arizona.edu [Department of Chemistry, The University of Arizona, P.O. Box 210041, Tucson, AZ 85721 (United States)

    2014-10-20

    Molecular-line observations of the bipolar planetary nebula (PN) M2-48 have been conducted using the Sub-Millimeter Telescope and the 12 m antenna of the Arizona Radio Observatory at 1, 2, and 3 mm. M2-48 is estimated to be ∼4800 yr old, midway through the PN evolutionary track. SiO and SO{sub 2} were detected in this source—the first identification of either molecule in a PN. CN, HCN, HNC, CS, SO, HCO{sup +}, N{sub 2}H{sup +}, and several {sup 13}C isotopologues such as {sup 13}CN, H{sup 13}CN, and H{sup 13}CO{sup +} were also observed toward this object. A radiative transfer analysis of multiple SiO transitions indicates a gas kinetic temperature of T {sub K} ∼ 55 K and a density of n(H{sub 2}) ∼ 9 × 10{sup 5} cm{sup –3} in M2-48, in agreement with previous CS and CO modeling. After CO, CN, and SO were found to be the most prevalent molecules in this nebula, with fractional abundances, relative to H{sub 2}, of f ∼ 3.8 × 10{sup –7} and 2.4 × 10{sup –7}, respectively. SO{sub 2} and HCN are also abundant, with f ∼ 1.2 × 10{sup –7}, indicating an [SO]/[SO{sub 2}] ratio of ∼2. Relatively high ion abundances were measured in M2-48 as well, with f ∼ 10{sup –7} for both HCO{sup +} and N{sub 2}H{sup +}. An [HCN]/[HNC] ratio of ∼2 was determined, as typically observed in other PNe, independent of age. The high abundances of SO and SO{sub 2}, along with the presence of SiO with f ∼ 2.9 × 10{sup –8}, suggest O/C > 1 in this source; furthermore, the prevalence of CN and N{sub 2}H{sup +} indicates nitrogen enrichment. The {sup 12}C/{sup 13}C ratio of ∼3 in the nebula was also established. These factors indicate hot-bottom burning occurred in the progenitor star of M2-48, suggesting an initial mass > 4 M {sub ☉}.

  11. Nucleation and condensation in the primitive solar nebula

    International Nuclear Information System (INIS)

    Cameron, A.G.W.; Fegley, M.B.

    1982-01-01

    It is pointed out that the primitive solar nebula may be modeled using the frictionally induced transport theory of Lynden-Bell and Pringle (1974) if the principal frictional mechanism within the nebula is turbulent viscosity. The present investigation is concerned with the construction of a model of a section of the primitive solar nebula as a basis for the study of nucleation and condensation processes within this section. The construction involves a relatively simple application of the Lynden-Bell and Pringle theory subject to steady mass flow conditions. The calculations which are conducted in connection with the investigation indicate that by the time the gas in the primitive solar nebula has become sufficiently supercooled to nucleate condensation centers, several different compounds, including the magnesium silicates forsterite and enstatite (MgSiO 3 ), will probably be able to condense on the growing condensation center

  12. The carbon budget in the outer solar nebula

    International Nuclear Information System (INIS)

    Simonelli, D.P.; Pollack, J.B.; Mckay, C.P.; Reynolds, R.T.; Summers, A.L.

    1989-01-01

    The compositional contrast between the giant-planet satellites and the significantly rockier Pluto/Charon system is indicative of different formation mechanisms; cosmic abundance calculations, in conjunction with an assumption of the Pluto/Charon system's direct formation from solar nebula condensates, strongly suggest that most of the carbon in the outer solar nebula was in CO form, in keeping with both the inheritance from the dense molecular clouds in the interstellar medium, and/or the Lewis and Prinn (1980) kinetic-inhibition model of solar nebula chemistry. Laboratory studies of carbonaceous chondrites and Comet Halley flyby studies suggest that condensed organic material, rather than elemental carbon, is the most likely candidate for the small percentage of the carbon-bearing solid in the outer solar nebula. 71 refs

  13. From red giant to planetary nebula - Dust, asymmetry, and polarization

    International Nuclear Information System (INIS)

    Johnson, J.J.; Jones, T.J.

    1991-01-01

    The polarization characteristics of stars in the stages of evolution from red giant to planetary nebula are investigated. Polarization is found to be a characteristic of the majority of these stars. The maximum observed polarization increases with age as the star evolves up the asymptotic giant branch (AGB) to the protoplanetary nebula phase, where the polarization reaches a maximum. The polarization then decreases as the star further evolves into a planetary nebula. These results indicate that aspherical mass loss is likely to be a continual feature of the late stages of stellar evolution, maintaining a clear continuity throughout the life of a star from the moment it first develops a measurable dust shell. The aspherical morphology seen in planetary nebulae has its origin in an intrinsic property of the star that is present at least as early as its arrival at the base of the AGB. 77 refs

  14. The [NeIV] Lines in High Excitation Gaseous Nebulae.

    Science.gov (United States)

    Aller, L H

    1970-04-01

    The "forbidden" lines of three times ionized neon are among the most precious indicators of electron temperature and excitation. They are also predicted to be among the strongest lines observed in the far ultraviolet spectra of high excitation nebulae.

  15. Possible mass distributions in the nebulae of other solar systems

    International Nuclear Information System (INIS)

    Brown, W.K.

    1987-01-01

    The supernova shell fragmentation model of solar system formation - previously shown to be successful in describing the mass distribution of our solar system - is used to calculate the mass distributions of other solar nebulae. (Auth.)

  16. Pulsar Wind Nebulae and Cosmic Rays: A Bedtime Story

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, A.

    2014-11-15

    The role pulsar wind nebulae play in producing our locally observed cosmic ray spectrum remains murky, yet intriguing. Pulsar wind nebulae are born and evolve in conjunction with SNRs, which are favored sites of Galactic cosmic ray acceleration. As a result they frequently complicate interpretation of the gamma-ray emission seen from SNRs. However, pulsar wind nebulae may also contribute directly to the local cosmic ray spectrum, particularly the leptonic component. This paper reviews the current thinking on pulsar wind nebulae and their connection to cosmic ray production from an observational perspective. It also considers how both future technologies and new ways of analyzing existing data can help us to better address the relevant theoretical questions. A number of key points will be illustrated with recent results from the VHE (E > 100 GeV) gamma-ray observatory VERITAS.

  17. Statistical and physical study of one-sided planetary nebulae.

    Science.gov (United States)

    Ali, A.; El-Nawawy, M. S.; Pfleiderer, J.

    The authors have investigated the spatial orientation of one-sided planetary nebulae. Most of them if not all are interacting with the interstellar medium. Seventy percent of the nebulae in the sample have inclination angles larger than 45° to the Galactic plane and 30% of the inclination angles are less than 45°. Most of the selected objects are old, evolved planetary nebulae with large dimensions, and not far away from the Galactic plane. Seventy-five percent of the objects are within 160 pc from the Galactic plane. The enhanced concavity arc can be explained physically as a result of the 'planetary nebulae-interstellar matter' interaction. The authors discuss the possible effect of the interstellar magnetic field in the concavity regions.

  18. On the evolution of central stars of planetary nebulae

    International Nuclear Information System (INIS)

    Yahel, R.Z.

    1977-01-01

    The evolution of nuclei of planetary nebulae has been calculated from the end of the ejection stage that produces the nebulae to the white dwarf stage. The structure of the central star is in agreement with the general picture of Finzi (1973) about the mass ejection from the progenitors of planetary nebulae. It has been found that in order to obtain evolutionary track consistent with the Harman-Seaton track (O'Dell, 1968) one has to assume that the masses of the nuclei stars are less than approximately 0.7 solar masses. The calculated evolutionary time scale of the central stars of planetary nebulae is approximately 2 x 10 4 yr. This time scale is negatively correlated with the stellar mass: the heavier the stellar mass, the shorter the evolutionary time scale. (Auth.)

  19. Chemical composition of planetary nebulae : Including ISO results

    NARCIS (Netherlands)

    Pottasch, [No Value; Beintema, DA; Salas, JB; Feibelman, WA; Henney, WJ; Franco, J; Martos, M; Pena, M

    2002-01-01

    The method of determining abundances using Infrared Space Observatory spectra is discussed. The results for seven planetary nebula are given. Using these data, a preliminary discussion of their evolution is given.

  20. Polarimetric evidence against a collimated outflow in the Horsehead Nebula

    Energy Technology Data Exchange (ETDEWEB)

    Warren-Smith, R F; Gledhill, T M; Scarrott, S M

    1985-08-01

    Imaging polarimetry of the Horsehead Nebula in Orion shows that the 'jaw' region of the nebula, which includes a proposed collimated flow from a highly reddened star B33-6, is illuminated by a distant source, sigma Orionis, and not by B33-6. The polarization pattern also shows features which suggest the presence of magnetically aligned dust grains in the surrounding medium. The possible structure of the aligning field is discussed.

  1. Complex molecules in the Orion Kleinmann-Low nebula

    Directory of Open Access Journals (Sweden)

    Despois D.

    2014-02-01

    Full Text Available In the framework of the delivery to the early Earth of extraterrestrial molecules, we have studied complex molecular species toward the Orion Kleinmann-Low nebula. This nebula is rich in molecules as well as in nascent stars and planetary systems. We focus here on HCOOCH3, CH3OCH3 and deuterated methanol. Upper limits on species of prebiotic interest like glycine were also obtained.

  2. Interpretation of the [ClIII] Lines in Gaseous Nebulae.

    Science.gov (United States)

    Aller, L H; Czyzak, S J; Walker, M F; Krueger, T K

    1970-05-01

    The intensity ratio of the green lambdalambda5517 and 5537 lines of [ClIII] serves as an indicatrix of the electron density in many gaseous nebulae whose spectra can be observed with an image converter. Quantitative interpretation of the line ratio requires accurate values of the collisional strengths and transition probabilities. With improved values of these parameters we have revised electron densities for a number of nebulae; the results seem to be in good accord with those derived from other criteria.

  3. The Boomerang Nebula - The Coldest Region of the Universe

    Science.gov (United States)

    Sahai, Raghvendra; Nyman, Lars-Ake

    1997-01-01

    In this letter, we report such observations of the Boomerang Nebula which show it to be a unique object, consisiting of an ultra-cold and extremely massive molecular envolope, expanding at very high speed. The extreeme physical characteristics of the Boomerang Nebula reported here have never been seen before in any AGB or post-AGB object, and should spur new theoretical and obesrvational efforts to understand the nature of the mass-loss processes occurring during later stellar evolution.

  4. Distribution of mass in the planetary system and solar nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Weidenschilling, S J [Carnegie Institution of Washington, D.C. (USA). Dept. of Terrestrial Magnetism

    1977-09-01

    A model 'solar nebula' is constructed by adding the solar complement of light elements to each planet, using recent models of planetary compositions. Uncertainties in this approach are estimated. The computed surface density varies approximately as rsup(-3/2). Mercury, Mars and the asteroid belt are anomalously low in mass, but processes exist which would preferentially remove matter from these regions. Planetary masses and compositions are generally consistent with a monotonic density distribution in the primordial solar nebula.

  5. Pulsar Wind Nebulae Created by Fast-Moving Pulsars

    OpenAIRE

    Kargaltsev, Oleg; Pavlov, George G.; Klingler, Noel; Rangelov, Blagoy

    2017-01-01

    We review multiwavelength properties of pulsar wind nebulae (PWNe) created by supersonically moving pulsars and the effects of pulsar motion on the PWN morphologies and the ambient medium. Supersonic pulsar wind nebulae (SPWNe) are characterized by bow-shaped shocks around the pulsar and/or cometary tails filled with the shocked pulsar wind. In the past several years significant advances in SPWN studies have been made in deep observations with the Chandra and XMM-Newton X-ray Observatories as...

  6. Integrated neurobiology of bipolar disorder

    Directory of Open Access Journals (Sweden)

    Vladimir eMaletic

    2014-08-01

    Full Text Available From a neurobiological perspective there is no such thing as bipolar disorder. Rather, it is almost certainly the case that many somewhat similar, but subtly different, pathological conditions produce a disease state that we currently diagnose as bipolarity. This heterogeneity—reflected in the lack of synergy between our current diagnostic schema and our rapidly advancing scientific understanding of the condition—limits attempts to articulate an integrated perspective on bipolar disorder. However, despite these challenges, scientific findings in recent years are beginning to offer a provisional unified field theory of the disease. This theory sees bipolar disorder as a suite of related neurodevelopmental conditions with interconnected functional abnormalities that often appear early in life and worsen over time. In addition to accelerated loss of volume in brain areas known to be essential for mood regulation and cognitive function, consistent findings have emerged at a cellular level, providing evidence that bipolar disorder is reliably associated with dysregulation of glial-neuronal interactions. Among these glial elements are microglia—the brain’s primary immune elements, which appear to be overactive in the context of bipolarity. Multiple studies now indicate that inflammation is also increased in the periphery of the body in both the depressive and manic phases of the illness, with at least some return to normality in the euthymic state. These findings are consistent with changes in the HPA axis, which are known to drive inflammatory activation. In summary, the very fact that no single gene, pathway or brain abnormality is likely to ever account for the condition is itself an extremely important first step in better articulating an integrated perspective on both its ontological status and pathogenesis. Whether this perspective will translate into the discovery of innumerable more homogeneous forms of bipolarity is one of the great

  7. Planetary Nebulae with H2 Emission

    OpenAIRE

    Margarita Rosado; Lorena Arias

    2003-01-01

    Hacemos una revisión de la emisión en hidrogeno molecular (H2) de las nebulosas planetarias (NPs). Vemos como esta emisión se encuentra asociada a objetos de forma bipolar. Describimos los niveles de energía de la molécula de hidrogeno, los principales mecanismos para poblarlos (choques y fluorescencia) y las formas en que se puede discriminar que mecanismo opera. Proponemos que la cinemática del H2 también puede ser usada para discriminar el mecanismo de excitación de sus líneas de emisión. ...

  8. PROBING THE ROSETTE NEBULA STELLAR BUBBLE WITH FARADAY ROTATION

    Energy Technology Data Exchange (ETDEWEB)

    Savage, Allison H.; Spangler, Steven R.; Fischer, Patrick D. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States)

    2013-03-01

    We report the results of Faraday rotation measurements of 23 background radio sources whose lines of sight pass through or close to the Rosette Nebula. We made linear polarization measurements with the Karl G. Jansky Very Large Array (VLA) at frequencies of 4.4 GHz, 4.9 GHz, and 7.6 GHz. We find the background Galactic contribution to the rotation measure in this part of the sky to be +147 rad m{sup -2}. Sources whose lines of sight pass through the nebula have an excess rotation measure of 50-750 rad m{sup -2}, which we attribute to the plasma shell of the Rosette Nebula. We consider two simple plasma shell models and how they reproduce the magnitude and sign of the rotation measure, and its dependence on distance from the center of the nebula. These two models represent different modes of interaction of the Rosette Nebula star cluster with the surrounding interstellar medium. Both can reproduce the magnitude and spatial extent of the rotation measure enhancement, given plausible free parameters. We contend that the model based on a stellar bubble more closely reproduces the observed dependence of rotation measure on distance from the center of the nebula.

  9. The Nature of the Stingray Nebula from Radio Observations

    Science.gov (United States)

    Harvey-Smith, Lisa; Hardwick, Jennifer A.; De Marco, Orsola; Parthasarathy, Mudumba; Gonidakis, Ioannis; Akhter, Shaila; Cunningham, Maria; Green, James A.

    2018-06-01

    We have analysed the full suite of Australia Telescope Compact Array data for the Stingray planetary nebula. Data were taken in the 4- to 23-GHz range of radio frequencies between 1991 and 2016. The radio flux density of the nebula generally declined during that period, but between 2013 and 2016 it shows signs of halting that decline. We produced the first spatially resolved radio images of the Stingray nebula from data taken in 2005. A ring structure, which appears to be associated with the ring seen in HST images, was visible. In addition, we found a narrow extension to the radio emission towards the eastern and western edges of the nebula. We derived the emission measure of the nebula - this decreased between 1992 and 2011, suggesting that the nebula is undergoing recombination. The radio spectral index is broadly consistent with a free-free emission mechanism, however a single data point hints that a steeper spectral index has possibly emerged since 2013, which could indicate the presence of synchrotron emission. If a non-thermal component component has emerged, such as one associated with a region that is launching a jet or outflow, we predict that it would intensify in the years to come.

  10. Featured Image: A Detailed Look at the Crab Nebula

    Science.gov (United States)

    Kohler, Susanna

    2017-07-01

    Planning on watching fireworks tomorrow? Heres an astronomical firework to help you start the celebrations! A new study has stunningly detailed the Crab Nebula (click for a closer look), a nebula 6,500 light-years away thought to have been formedby a supernova explosion and the subsequent ultrarelativistic wind emitted by the pulsar at its heart. Led by Gloria Dubner (University of Buenos Aires), the authors of this study obtained new observations of the Crab Nebula from five different telescopes. They compiled these observations to compare the details of the nebulas structure across different wavelengths, which allowedthem to learnabout the sources of various features within the nebula. In the images above, thetop left shows the 3 GHz data from the Very Large Array (radio). Moving clockise, the radio data (shown in red) is composited with: infrared data from Spitzer Space Telescope, optical continuum from Hubble Space Telescope, 500-nm optical datafrom Hubble, and ultraviolet data from XMM-Newton. The final two images are of the nebula center, and they are composites of the radio imagewith X-ray data from Chandra and near-infrared data from Hubble. To read more about what Dubner and collaborators learned (and to see more spectacular images!), check out the paper below.CitationG. Dubner et al 2017 ApJ 840 82. doi:10.3847/1538-4357/aa6983

  11. Bipolar Disorder and Alcoholism: Are They Related?

    Science.gov (United States)

    ... Are they related? Is there a connection between bipolar disorder and alcoholism? Answers from Daniel K. Hall-Flavin, M.D. Bipolar disorder and alcoholism often occur together. Although the association ...

  12. Bipolar outflow in B335

    International Nuclear Information System (INIS)

    Hirano, N.; Kameya, O.; Nakayama, M.; Takakubo, K.

    1988-01-01

    The high-velocity (C-12)O (J = 1-0) emission in B335 with a high angular resolution of 16 arcsec has been mapped. The high-velocity emission shows distinct bipolar pattern centered at IRAS 19345+0727, toward which a strong high-velocity (C-12)O emission has been detected. The bipolar lobes delineate remarkable collimation toward the IRAS source, indicating that the flow is focused within 0.02 pc of the driving source. Each lobe is accompanied by significant wing emission with the opposite velocity shift, which clearly shows the association with IRAS 19345+0727. This feature is well explained as a bipolar flow the axis of which is nearly perpendicular to the line of sight. There is no evidence of another evolved bipolar flow which does not associate with any dense core as previously suggested. This suggests that B335 is a site of very recent star formation, containing a single bipolar flow with an age of about 30,000 yr. 15 references

  13. Exercising control over bipolar disorder.

    Science.gov (United States)

    Malhi, Gin S; Byrow, Yulisha

    2016-11-01

    Following extensive research exercise has emerged as an effective treatment for major depressive disorder, and it is now a recognised therapy alongside other interventions. In contrast, there is a paucity of research examining the therapeutic effects of exercise for those with bipolar disorder. Given that dysfunctional reward processing is central to bipolar disorder, research suggests that exercise can perhaps be framed as a reward-related event that may have the potential to precipitate a manic episode. The behavioural activation system (BAS) is a neurobehavioural system that is associated with responding to reward and provides an appropriate framework to theoretically examine and better understand the effects of exercise treatment on bipolar disorder. This article discusses recent research findings and provides an overview of the extant literature related to the neurobiological underpinnings of BAS and exercise as they relate to bipolar disorder. This is important clinically because depending on mood state in bipolar disorder, we postulate that exercise could be either beneficial or deleterious with positive or negative effects on the illness. Clearly, this complicates the evaluation of exercise as a potential treatment in terms of identifying its optimal characteristics in this population. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  14. Late Onset Bipolar Disorder: Case Report

    OpenAIRE

    Filipa Araújo; Adriana Horta

    2016-01-01

    Background: Bipolar disorder affects approximately 1% of the population, with diagnosis often being made during late adolescence and early adulthood, and only rarely (0.1%) in the elderly. Late onset bipolar disorder in the elderly has a impact on the nature and course of bipolar disorder. Aims: The authors report a case of bipolar disorder emerging in late life  (76years old) with no cleary identified organic cause. Conclusion: This case highlights the importance of a broad different...

  15. Imunologia do transtorno bipolar Immunology of bipolar disorder

    Directory of Open Access Journals (Sweden)

    Izabela Guimarães Barbosa

    2009-01-01

    Full Text Available OBJETIVO: Pesquisas recentes têm implicado fatores imunes na patogênese de diversos transtornos neuropsiquiátricos. O objetivo do presente trabalho é revisar os trabalhos que investigaram a associação entre transtorno bipolar e alterações em parâmetros imunes. MÉTODOS: Artigos que incluíam as palavras-chave: "bipolar disorder", "mania", "immunology", "cytokines", "chemokines", "interleukins", "interferon" e "tumor necrosis factor" foram selecionados em uma revisão sistemática da literatura. As bases de dados avaliadas foram MedLine e Scopus, entre os anos de 1980 e 2008. RESULTADOS: Foram identificados 28 trabalhos que estudaram alterações imunes em pacientes com transtorno bipolar. Seis artigos investigaram genes relacionados à resposta imune; cinco, autoanticorpos; quatro, populações leucocitárias; 13, citocinas e/ou moléculas relacionadas à resposta imune e seis, leucócitos de pacientes in vitro. CONCLUSÕES: Embora haja evidências na literatura correlacionando o transtorno bipolar a alterações imunes, os dados não são conclusivos. O transtorno bipolar parece estar associado a níveis mais elevados de autoanticorpos circulantes, assim como à tendência à ativação imune com produção de citocinas pró-inflamatórias e redução de parâmetros anti-inflamatórios.OBJECTIVE: Emerging research has implicated immune factors in the pathogenesis of a variety of neuropsychiatric disorders. The objective of the present paper is to review the studies that investigated the association between bipolar disorder and immune parameters. METHODS: Papers that included the keywords "bipolar to disorder", "mania", "immunology", "cytokines", "chemokines", "interleukins", "interferon" and "tumor necrosis factor" were selected in a systematic review of the literature. The evaluated databases were MedLine and Scopus in the period between 1980 and 2008. RESULTS: Twenty eight works were found. Six studies investigated immune response

  16. The carbon budget in the outer solar nebula.

    Science.gov (United States)

    Simonelli, D P; Pollack, J B; McKay, C P; Reynolds, R T; Summers, A L

    1989-01-01

    Detailed models of the internal structures of Pluto and Charon, assuming rock and water ice as the only constituents, indicate that the mean silicate mass fraction of this two-body system is on the order of 0.7; thus the Pluto/Charon system is significantly "rockier" than the satellites of the giant planets (silicate mass fraction approximately 0.55). This compositional contrast reflects different formation mechanisms: it is likely that Pluto and Charon formed directly from the solar nebula, while the circumplanetary nebulae that produced the giant planet satellites were derived from envelopes that surrounded the forming giant planets (envelopes in which icy planetesimals dissolved more readily than rocky planetesimals). Simple cosmic abundance calculations, and the assumption that the Pluto/Charon system formed directly from solar nebula condensates, strongly suggest that the majority of the carbon in the outer solar nebula was in the form of carbon monoxide; these results are consistent with (1) inheritance from the dense molecular clouds in the interstellar medium (where CH4/CO nebula chemistry. Theoretical predictions of the C/H enhancements in the atmospheres of the giant planets, when compared to the actual observed enhancements, suggest that 10%, or slightly more, of the carbon in the outer solar nebula was in the form of condensed materials (although the amount of condensed C may have dropped slightly with increasing heliocentric distance). Strict compositional limits computed for the Pluto/Charon system using the densities of CH4 and CO ices indicate that these pure ices are at best minor components in the interiors of these bodies, and imply that CH4 and CO ices were not the dominant C-bearing solids in the outer nebula. Clathrate-hydrates could not have appropriated enough CH4 or CO to be the major form of condensed carbon, although such clathrates may be necessary to explain the presence of methane on Pluto after its formation from a CO-rich nebula

  17. Mixing and Transport in the Solar Nebula

    Science.gov (United States)

    Boss, Alan P.

    2003-01-01

    Boss & Vanhala (2000, 2001) prepared reviews of triggered collapse and injection models, using Prudence Foster's finite differences code at very high spatial resolution (440 x 1440 cells) to demonstrate the convergence of the R-T fingers in triggered injection models. A two dimensional hydrodynamical calculation with unprecedentedly high spatial resolution (960 x 2880 zones, or almost 3 million grid points) demonstrated that it suitable shock front can both trigger the collapse of an otherwise stable presolar cloud, and inject shock front particles into the collapsing cloud through the formation of what become Rayleigh-Taylor fingers of compressed fluid layers falling into the gravitational potential well of the growing protostar. These calculations suggest that heterogeneity derived from these R-T fingers will persist down to the scale of their injection onto the surface of the solar nebula. Haghighipour developed a numerical code capable of calculating the orbital evolution of dust grains of varied sizes in a gaseous nebula, subject to Epstein and Stokes drag as well as the self-gravity of the disk. In collaboration with the PI and George W. Wetherill, Haghighipour has been involved in development of a new idea on the possibility of rapid formation of ice giant planets via the disk instability mechanism. Haghighipour studied the stability of a five-body system consisting of the Sun and four protoplanets by numerically integrating their equations of motions. Using Levison and Duncan s SWIFT integrator, Haghighipour showed that, depending on the orbital parameters of the bodies, such a system can be stable for 0.1-10 Myr. Time periods of 1 Myr or more are long enough to be consistent with the time scale proposed for the formation of giant planets by the disk instability mechanism and the photoevaporation of the gaseous envelopes of the outermost protoplanets by a nearby OB star, resulting in the formation of ice giant planets. The PI has used his three dimensional

  18. Mathematical models of bipolar disorder

    Science.gov (United States)

    Daugherty, Darryl; Roque-Urrea, Tairi; Urrea-Roque, John; Troyer, Jessica; Wirkus, Stephen; Porter, Mason A.

    2009-07-01

    We use limit cycle oscillators to model bipolar II disorder, which is characterized by alternating hypomanic and depressive episodes and afflicts about 1% of the United States adult population. We consider two non-linear oscillator models of a single bipolar patient. In both frameworks, we begin with an untreated individual and examine the mathematical effects and resulting biological consequences of treatment. We also briefly consider the dynamics of interacting bipolar II individuals using weakly-coupled, weakly-damped harmonic oscillators. We discuss how the proposed models can be used as a framework for refined models that incorporate additional biological data. We conclude with a discussion of possible generalizations of our work, as there are several biologically-motivated extensions that can be readily incorporated into the series of models presented here.

  19. Signatures of Chemical Evolution in Protostellar Nebulae

    Science.gov (United States)

    Nuth, Joseph A., III; Johnson, Natasha

    2011-01-01

    A decade ago observers began to take serious notice of the presence of crystalline silicate grains in the dust flowing away from some comets. While crystallinity had been seen in such objects previously, starting with the recognitions by Campins and Ryan (1990) that the 10 micron feature of Comet Halley resembled that of the mineral forsterite, most such observations were either ignored or dismissed as no path to explain such crystalline grains was available in the literature. When it was first suggested that an outward flow must be present to carry annealed silicate grains from the innermost regions of the Solar Nebula out to the regions where comets could form (Nuth, 1999; 2001) this suggestion was also dismissed because no such transport mechanism was known at the time. Since then not only have new models of nebular dynamics demonstrated the reality of long distance outward transport (Ciesla, 2007; 2008; 2009) but examination of older models (Boss, 2004) showed that such transport had been present but had gone unrecognized for many years. The most unassailable evidence for outward nebular transport came with the return of the Stardust samples from Comet Wild2, a Kuiper-belt comet that contained micron-scale grains of high temperature minerals resembling the Calcium-Aluminum Inclusions found in primitive meteorites (Zolensky et aI., 2006) that formed at T > 1400K. Now that outward transport in protostellar nebulae has been firmly established, a re-examination of its consequences for nebular gas is in order that takes into account both the factors that regulate both the outward flow as well as those that likely control the chemical composition of the gas. Laboratory studies of surface catalyzed reactions suggest that a trend toward more highly reduced carbon and nitrogen compounds in the gas phase should be correlated with a general increase in the crystallinity of the dust (Nuth et aI., 2000), but is such a trend actually observable? Unlike the Fischer-Tropsch or

  20. Star Formation in the Orion Nebula Cluster

    Science.gov (United States)

    Palla, Francesco; Stahler, Steven W.

    1999-11-01

    We study the record of star formation activity within the dense cluster associated with the Orion Nebula. The bolometric luminosity function of 900 visible members is well matched by a simplified theoretical model for cluster formation. This model assumes that stars are produced at a constant rate and distributed according to the field-star initial mass function. Our best-fit age for the system, within this framework, is 2×106 yr. To undertake a more detailed analysis, we present a new set of theoretical pre-main-sequence tracks. These cover all masses from 0.1 to 6.0 Msolar, and start from a realistic stellar birthline. The tracks end along a zero-age main-sequence that is in excellent agreement with the empirical one. As a further aid to cluster studies, we offer an heuristic procedure for the correction of pre-main-sequence luminosities and ages to account for the effects of unresolved binary companions. The Orion Nebula stars fall neatly between our birthline and zero-age main-sequence in the H-R diagram. All those more massive than about 8 Msolar lie close to the main sequence, as also predicted by theory. After accounting for the finite sensitivity of the underlying observations, we confirm that the population between 0.4 and 6.0 Msolar roughly follows a standard initial mass function. We see no evidence for a turnover at lower masses. We next use our tracks to compile stellar ages, also between 0.4 and 6.0 Msolar. Our age histogram reveals that star formation began at a low level some 107 yr ago and has gradually accelerated to the present epoch. The period of most active formation is indeed confined to a few×106 yr, and has recently ended with gas dispersal from the Trapezium. We argue that the acceleration in stellar births, which extends over a wide range in mass, reflects the gravitational contraction of the parent cloud spawning this cluster.

  1. Is bipolar always bipolar? Understanding the controversy on bipolar disorder in children

    Science.gov (United States)

    Grimmer, Yvonne; Hohmann, Sarah

    2014-01-01

    Dramatically increasing prevalence rates of bipolar disorder in children and adolescents in the United States have provoked controversy regarding the boundaries of manic symptoms in child and adolescent psychiatry. The serious impact of this ongoing debate on the treatment of affected children is reflected in the concomitant increase in prescription rates for antipsychotic medication. A key question in the debate is whether this increase in bipolar disorder in children and adolescents is based on a better detection of early-onset bipolar disorder—which can present differently in children and adolescents—or whether it is caused by an incorrect assignment of symptoms which overlap with other widely known disorders. So far, most findings suggest that the suspected symptoms, in particular chronic, non-episodic irritability (a mood symptom presenting with easy annoyance, temper tantrums and anger) do not constitute a developmental presentation of childhood bipolar disorder. Additional research based on prospective, longitudinal studies is needed to further clarify the developmental trajectories of bipolar disorder and the diagnostic status of chronic, non-episodic irritability. PMID:25580265

  2. Bipolar dislocation of the clavicle

    Directory of Open Access Journals (Sweden)

    Wei Jiang

    2012-01-01

    Full Text Available Bipolar dislocation of the clavicle at acromioclavicular and sternoclavicular joint is an uncommon traumatic injury. The conservative treatments adopted in the past is associated with redislocation dysfunction and deformity. A 41 years old lady with bipolar dislocation of right shoulder is treated surgically by open reduction and internal fixation by oblique T-plate at sternoclavicular joint and Kirschner wire stabilization at acromioclavicular joint. The patient showed satisfactory recovery with full range of motion of the right shoulder and normal muscular strength. The case reported in view of rarity and at 2 years followup.

  3. Transcultural aspects of bipolar disorder

    OpenAIRE

    Sanches, Marsal; Jorge, Miguel Roberto

    2004-01-01

    Considerando-se que existem diferenças importantes na maneira como as emoções são vivenciadas e expressas em diferentes culturas, a apresentação e o manejo do transtorno afetivo bipolar sofrem influência de fatores culturais. O presente artigo realiza uma breve revisão da evidência referente aos aspectos transculturais do transtorno bipolar.Cultural variations in the expression of emotions have been described. Consequently, there are cross-cultural influences on the diagnosis and management o...

  4. The central star candidate of the planetary nebula Sh2-71: photometric and spectroscopic variability

    Science.gov (United States)

    Močnik, T.; Lloyd, M.; Pollacco, D.; Street, R. A.

    2015-07-01

    We present the analysis of several newly obtained and archived photometric and spectroscopic data sets of the intriguing and yet poorly understood 13.5 mag central star candidate of the bipolar planetary nebula Sh2-71. Photometric observations confirmed the previously determined quasi-sinusoidal light curve with a period of 68 d and also indicated periodic sharp brightness dips, possibly eclipses, with a period of 17.2 d. In addition, the comparison between U and V light curves revealed that the 68 d brightness variations are accompanied by a variable reddening effect of ΔE(U - V) = 0.38. Spectroscopic data sets demonstrated pronounced variations in spectral profiles of Balmer, helium and singly ionized metal lines and indicated that these variations occur on a time-scale of a few days. The most accurate verification to date revealed that spectral variability is not correlated with the 68 d brightness variations. The mean radial velocity of the observed star was measured to be ˜26 km s-1 with an amplitude of ±40 km s-1. The spectral type was determined to be B8V through spectral comparison with synthetic and standard spectra. The newly proposed model for the central star candidate is a Be binary with a misaligned precessing disc.

  5. An analytical model for the evolution of the coldest component of the Boomerang Nebula

    Science.gov (United States)

    Bohigas, J.

    2017-04-01

    The most striking feature of the Boomerang Nebula is a large nearly spherical cloud where the temperature is close to 2 K. At its inner and outer boundaries, this cloud is expanding at velocities close to 35 and 180 km s-1. The cloud surrounds an asymptotic giant branch (AGB) star and a smaller bipolar molecular cloud, expanding much more slowly. The ultracold spherical cloud has been and still is expanding into a rarefied medium, since there is no trace of a shock wave. This ultracold cloud is modelled using the analytical solution for a power-driven expansion of a spherically symmetric cloud, followed by an adiabatic expansion phase, both into a vacuum. Assuming that the cloud is at a distance of 1500 pc, the present temperature and velocity profile are reproduced with a model where the cloud has an energy close to 8.5 × 1046 erg per solar mass and was ejected 1000 yr ago. In this model, the power-driven phase lasts for ˜10 yr and half of the energy is injected in less than a year. The general features of this model, are amenable with what is found in other spherical shells surrounding AGB stars, the small amount of mass lost by massive OH/IR stars and evolutionary models indicating that there may be extremely high and abrupt mass-loss phases in AGB stars. The energy and time-scale suggest that the ejection of the cold spherical cloud was an intermediate luminosity transient.

  6. Electronic monitoring in bipolar disorder.

    Science.gov (United States)

    Faurholt-Jepsen, Maria

    2018-03-01

    Major reasons for the insufficient effects of current treatment options in bipolar disorder include delayed intervention for prodromal depressive and manic symptoms and decreased adherence to psychopharmacological treatment. The reliance on subjective information and clinical evaluations when diagnosing and assessing the severity of depressive and manic symptoms calls for less biased and more objective markers. By using electronic devices, fine-grained data on complex psychopathological aspects of bipolar disorder can be evaluated unobtrusively over the long term. Moreover, electronic data could possibly represent candidate markers of diagnosis and illness activity in bipolar disorder and allow for early and individualized intervention for prodromal symptoms outside clinical settings. 
The present dissertation concerns the use of electronic monitoring as a marker and treatment intervention in bipolar disorder and investigated the scientific literature and body of evidence within the area, which includes ten original study reports and two systematic reviews, one of which included a meta-analysis, conducted by the author of the dissertation. 
Taken together, the literature presented in this dissertation illustrates that 1) smartphone-based electronic self-monitoring of mood seems to reflect clinically assessed depressive and manic symptoms and enables the long-term characterization of mood

instability in bipolar disorder; 2) preliminary results suggest that smartphone-based automatically generated data (e.g. the number of text messages sent/day; the number of incoming and outgoing calls/day; the number of changes in cell tower IDs/day; and voice features) seem to reflect clinically assessed depressive and manic symptoms in bipolar disorder; 3) smartphone-based electronic self-monitoring had no effects on the severity of depressive and manic symptoms in bipolar disorder, according to a randomized controlled trial; and 4) electronic monitoring of psychomotor

  7. Pinwheel Nebula around WR 98a.

    Science.gov (United States)

    Monnier; Tuthill; Danchi

    1999-11-10

    We present the first near-infrared images of the dusty Wolf-Rayet star WR 98a. Aperture-masking interferometry has been utilized to recover images at the diffraction limit of the Keck I telescope, less, similar50 mas at 2.2 µm. Multiepoch observations spanning about 1 yr have resolved the dust shell into a "pinwheel" nebula, the second example of a new class of dust shell first discovered around WR 104 by Tuthill, Monnier, & Danchi. Interpreting the collimated dust outflow in terms of an interacting winds model, the binary orbital parameters and apparent wind speed are derived: a period of 565+/-50 days, a viewing angle of 35&j0;+/-6 degrees from the pole, and a wind speed of 99+/-23 mas yr-1. This period is consistent with a possible approximately 588 day periodicity in the infrared light curve, linking the photometric variation to the binary orbit. Important implications for binary stellar evolution are discussed by identifying WR 104 and WR 98a as members of a class of massive, short-period binaries whose orbits were circularized during a previous red supergiant phase. The current component separation in each system is similar to the diameter of a red supergiant, which indicates that the supergiant phase was likely terminated by Roche lobe overflow, leading to the present Wolf-Rayet stage.

  8. Planetary Nebulae and How to Observe Them

    CERN Document Server

    Griffiths, Martin

    2012-01-01

    Astronomers' Observing Guides provide up-to-date information for amateur astronomers who want to know all about what is it they are observing. This is the basis of the first part of the book. The second part details observing techniques for practical astronomers, working with a range of different instruments. Planetary Nebulae and How to Observe Them is intended for amateur astronomers who want to concentrate on one of the most beautiful classes of astronomical objects in the sky. This book will help the observer to see these celestial phenomena using telescopes of various apertures. As a Sun-like star reaches the end of its life, its hydrogen fuel starts to run out. It collapses until helium nuclei begin nuclear fusion, whereupon the star begins to pulsate, each pulsation throwing off a layer of the star's atmosphere. Eventually the atmosphere has all been ejected as an expanding cloud of gas, the star's core is exposed and ultraviolet photons cause the shell of gas to glow brilliantly - that's planetary ...

  9. Radio Observations of Elongated Pulsar Wind Nebulae

    Science.gov (United States)

    Ng, Stephen C.-Y.

    2015-08-01

    The majority of pulsars' rotational energy is carried away by relativistic winds, which are energetic particles accelerated in the magnetosphere. The confinement of the winds by the ambient medium result in synchrotron bubbles with broad-band emission, which are commonly referred to as pulsar wind nebulae (PWNe). Due to long synchrotron cooling time, a radio PWN reflects the integrated history of the system, complementing information obtained from the X-ray and higher energy bands. In addition, radio polarization measurements can offer a powerful probe of the PWN magnetic field structure. Altogether these can reveal the physical conditions and evolutionary history of a system.I report on preliminary results from high-resolution radio observations of PWNe associated with G327.1-1.1, PSRs J1015-5719, B1509-58, and J1549-4848 taken with the Australia Telescope Compact Array (ATCA). Their magnetic field structure and multiwavelength comparison with other observations are discussed.This work is supported by a ECS grant of the Hong Kong Government under HKU 709713P. The Australia Telescope is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO.

  10. Scaled Eagle Nebula Experiments on NIF

    Energy Technology Data Exchange (ETDEWEB)

    Pound, Marc W. [Univ. of Maryland, College Park, MD (United States)

    2017-03-28

    We performed scaled laboratory experiments at the National Ignition Facility laser to assess models for the creation of pillar structures in star-forming clouds of molecular hydrogen, in particular the famous Pillars of the Eagle Nebula. Because pillars typically point towards nearby bright ultraviolet stars, sustained directional illumination appears to be critical to pillar formation. The experiments mock up illumination from a cluster of ultraviolet-emitting stars, using a novel long duration (30--60 ns), directional, laser-driven x-ray source consisting of multiple radiation cavities illuminated in series. Our pillar models are assessed using the morphology of the Eagle Pillars observed with the Hubble Space Telescope, and measurements of column density and velocity in Eagle Pillar II obtained at the BIMA and CARMA millimeter wave facilities. In the first experiments we assess a shielding model for pillar formation. The experimental data suggest that a shielding pillar can match the observed morphology of Eagle Pillar II, and the observed Pillar II column density and velocity, if augmented by late time cometary growth.

  11. Planetary nebulae: 20 years of Hubble inquiry

    Science.gov (United States)

    Balick, Bruce

    2012-08-01

    The Hubble Space Telescope has served the critical roles of microscope and movie camera in the past 20 years of research on planetary nebulae (``PNe''). We have glimpsed the details of the evolving structures of neutral and ionized post-AGB objects, built ingenious heuristic models that mimic these structures, and constrained most of the relevant physical processes with careful observations and interpretation. We have searched for close physical binary stars with spatial resolution ~50 AU at 1 AU, located jets emerging from the nucleus at speeds up to 2000 km s-1 and matched newly discovered molecular and X-ray emission regions to physical substructures in order to better understand how stellar winds and ionizing radiation interact to form the lovely symmetries that are observed. Ultraviolet spectra of CNO in PNe help to uncover how stars process deep inside AGB stars with unstable nuclear burning zones. HST broadband imaging has been at the forefront of uncovering surprisingly complex wind morphologies produced at the tip of the AGB, and has led to an increasing realization of the potentially vital roles of close binary stars and emerging magnetic fields in shaping stellar winds.

  12. Continuous emission from the gaseous nebula beyond the Lyman limit

    International Nuclear Information System (INIS)

    Bolgova, G.T.; Khromov, G.S.

    1975-01-01

    Models of spherically-symmetric isothermic hydrogen nebula with an exciting star in the centre are considered. Spectra and energies of diffuse radiation of nebula and of direct radiation of its kernel are calculated in the Lyman continuum for the external boundary of the object. The spectrum of the diffuse radiation is shown to be to a great extent invariant in relation to all parameters of models except for Tsub(e). The total loss in energy of Lsub(c)-radiation of kernel through the external border of the ionized nebula, amounts to 20-30% in the average even at a considerable optical thickness of the object tausub(0). The greater part of this energy is transferred via direct ionizing radiation, though the relative contribution of the diffuse Lsub(c)-radiation of nebula reaches 30% at low temperatures of the exciting star and at large tausub(0). The results of this work may be applied to calculating the energy balance of the star-nebula system, the heating of dust particles and ionization of the neighbouring interstellar medium, and also for determining the conditions of observation of the far ultra-violet radiation of similar objects

  13. A turbulent two-phase flow model for nebula flows

    International Nuclear Information System (INIS)

    Champney, J.M.; Cuzzi, J.N.

    1990-01-01

    A new and very efficient turbulent two-phase flow numericaly model is described to analyze the environment of a protoplanetary nebula at a stage prior to the formation of planets. Focus is on settling processes of dust particles in flattened gaseous nebulae. The model employs a perturbation technique to improve the accuracy of the numerical simulations of such flows where small variations of physical quantities occur over large distance ranges. The particles are allowed to be diffused by gas turbulence in addition to settling under gravity. Their diffusion coefficients is related to the gas turbulent viscosity by the non-dimensional Schmidt number. The gas turbulent viscosity is determined by the means of the eddy viscosity hypothesis that assumes the Reynolds stress tensor proportional to the mean strain rate tensor. Zero- and two-equation turbulence models are employed. Modeling assumptions are detailed and discussed. The numerical model is shown to reproduce an existing analytical solution for the settling process of particles in an inviscid nebula. Results of nebula flows are presented taking into account turbulence effects of nebula flows. Diffusion processes are found to control the settling of particles. 24 refs

  14. Spectral and interferometric observation of four emission nebulas

    International Nuclear Information System (INIS)

    Lozinskaya, T.A.; Klement'eva, A.Yu.; Zhukov, G.V.; Shenavrin, V.I.

    1975-01-01

    Results of spectrophotometric and interferometric observations of four emission nebulae are presented; electron temperature Te and electron density Ne are estimated; mean beam velocities and parameters of the internal motion in the nebylae are determined. The following objects have been investigated: 1) a bright compact nebulae of unknown nature 2.5 in size which is identified with the non-thermal radiosource G6.4-0.5 in the region W28; 2) nebulae RCW171 5' in size which is identified with the radiosource G23.1+0.6; 3) the nebulae Simeiz 34/Sharpless 261/d 1950 =6sup(h)05sup(m), sigma 1950 =+15 deg 49'; its diameter is approximately 30 an extensive complex of bright emission fibres in the nebulae Swan, which are partially projected into a possible remainder of the outburst of a supernova W63; L 1950 =20sup(h)17sup(m); S 1950 =45 deg 30' its diameter is approximately 1 deg 5

  15. On the injection of relativistic particles into the Crab Nebula

    International Nuclear Information System (INIS)

    Shklovskij, I.S.

    1977-01-01

    It is shown that a flux of relativistic electrons from the NP 0532 pulsar magnetosphere, responsible for its synchrotron emission, cannot provide the necessary energy pumping to the Crab Nebula. A conclusion is reached that such a pumping can be effectuated by a flow of relativistic electrons leaving the NP 0532 magnetosphere at small pitch angles and giving therefore no appreciable contribution to the synchrotron emission of the pulsar. An interpretation of the Crab Nebula synchrotron spectrum is given on the assumption of secular ''softening'' of the energy spectrum of the relativistic electrons injected into the Nebula. A possibility of explanation of the observed rapid variability of some features in the central part of the Nebula by ejection of free - neutron - rich dense gas clouds from the pulsar surface during ''starquakes'' is discussed. The clouds of rather dense (nsub(e) approximately 10 7 cm -3 ) plasma, thus formed at about 10 13 cm from pulsar, will be accelerated up to relativistic velocities by the pressure of the magneto-dipole radiation of NP 0532 and will deform the magnetic field in the inner part (R 17 cm) of the Crab Nebula, that is the cause of the variability observed. In this case, favourable conditions for the acceleration of the particles in the cloud up to relativistic energies are realized; that may be an additional source of injection

  16. The spatial distribution of infrared radiation from visible reflection nebulae

    Science.gov (United States)

    Luan, Ling; Werner, Michael W.; Dwek, Eli; Sellgren, Kris

    1989-01-01

    The emission at IRAS 12 and 25 micron bands of reflection nebulae is far in excess of that expected from the longer wavelength equilibrium thermal emission. The excess emission in the IRAS 12 micron band is a general phenomenon, seen in various components of interstellar medium such as IR cirrus clouds, H II regions, atomic and molecular clouds, and also normal spiral galaxies. This excess emission has been attributed to UV excited fluorescence in polycyclic aromatic hydrocarbon (PAH) molecules or to the effect of temperature fluctuations in very small grains. Results are presented of studies of IRAS data on reflection nebulae selected from the van den Bergh reflection nebulae sample. Detailed scans of flux ratio and color temperature across the nebulae were obtained in order to study the spatial distribution of IR emission. A model was used to predict the spatial distribution of IR emission from dust grains illuminated by a B type star. The model was also used to explore the excitation of the IRAS 12 micron band emission as a function of stellar temperature. The model predictions are in good agreement with the analysis of reflection nebulae, illuminated by stars with stellar temperature ranging from 21,000 down to 3,000 K.

  17. Gamma rays and neutrinos from the Crab Nebula produced by pulsar accelerated nuclei

    OpenAIRE

    Bednarek, W.; Protheroe, R. J.

    1997-01-01

    We investigate the consequences of the acceleration of heavy nuclei (e.g. iron nuclei) by the Crab pulsar. Accelerated nuclei can photodisintegrate in collisions with soft photons produced in the pulsar's outer gap, injecting energetic neutrons which decay either inside or outside the Crab Nebula. The protons from neutron decay inside the nebula are trapped by the Crab Nebula magnetic field, and accumulate inside the nebula producing gamma-rays and neutrinos in collisions with the matter in t...

  18. Social support and bipolar disorder

    Directory of Open Access Journals (Sweden)

    Paula Mendonça Studart

    2015-08-01

    Full Text Available Background Bipolar disorder is a chronic condition that affects the functioning of its carriers in many different ways, even when treated properly. Therefore, it’s also important to identify the psychosocial aspects that could contribute to an improvement of this population’s quality of life.Objective Carry out a literature review on the role of social support in cases of bipolar disorder.Method A research on the following online databases PubMed, Lilacs and SciELO was conducted by using the keywords “social support” or “social networks” and “mood disorders” or “bipolar disorder” or “affective disorder,” with no defined timeline.Results Only 13 studies concerning the topic of social support and BD were found in the search for related articles. Generally speaking, the results show low rates of social support for BD patients.Discussion Despite the growing interest in the overall functioning of patients with bipolar disorder, studies on social support are still rare. Besides, the existing studies on the subject use different methodologies, making it difficult to establish data comparisons.

  19. Electronic monitoring in bipolar disorder

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria

    2018-01-01

    generated data (e.g. the number of text messages sent/day; the number of incoming and outgoing calls/day; the number of changes in cell tower IDs/day; and voice features) seem to reflect clinically assessed depressive and manic symptoms in bipolar disorder; 3) smartphone-based electronic self-monitoring had...

  20. Integrated Neurobiology of Bipolar Disorder

    Science.gov (United States)

    Maletic, Vladimir; Raison, Charles

    2014-01-01

    From a neurobiological perspective there is no such thing as bipolar disorder. Rather, it is almost certainly the case that many somewhat similar, but subtly different, pathological conditions produce a disease state that we currently diagnose as bipolarity. This heterogeneity – reflected in the lack of synergy between our current diagnostic schema and our rapidly advancing scientific understanding of the condition – limits attempts to articulate an integrated perspective on bipolar disorder. However, despite these challenges, scientific findings in recent years are beginning to offer a provisional “unified field theory” of the disease. This theory sees bipolar disorder as a suite of related neurodevelopmental conditions with interconnected functional abnormalities that often appear early in life and worsen over time. In addition to accelerated loss of volume in brain areas known to be essential for mood regulation and cognitive function, consistent findings have emerged at a cellular level, providing evidence that bipolar disorder is reliably associated with dysregulation of glial–neuronal interactions. Among these glial elements are microglia – the brain’s primary immune elements, which appear to be overactive in the context of bipolarity. Multiple studies now indicate that inflammation is also increased in the periphery of the body in both the depressive and manic phases of the illness, with at least some return to normality in the euthymic state. These findings are consistent with changes in the hypothalamic–pituitary–adrenal axis, which are known to drive inflammatory activation. In summary, the very fact that no single gene, pathway, or brain abnormality is likely to ever account for the condition is itself an extremely important first step in better articulating an integrated perspective on both its ontological status and pathogenesis. Whether this perspective will translate into the discovery of innumerable more homogeneous forms of

  1. Lifetime of the solar nebula constrained by meteorite paleomagnetism.

    Science.gov (United States)

    Wang, Huapei; Weiss, Benjamin P; Bai, Xue-Ning; Downey, Brynna G; Wang, Jun; Wang, Jiajun; Suavet, Clément; Fu, Roger R; Zucolotto, Maria E

    2017-02-10

    A key stage in planet formation is the evolution of a gaseous and magnetized solar nebula. However, the lifetime of the nebular magnetic field and nebula are poorly constrained. We present paleomagnetic analyses of volcanic angrites demonstrating that they formed in a near-zero magnetic field (nebula field, and likely the nebular gas, had dispersed by this time. This sets the time scale for formation of the gas giants and planet migration. Furthermore, it supports formation of chondrules after 4563.5 million years ago by non-nebular processes like planetesimal collisions. The core dynamo on the angrite parent body did not initiate until about 4 to 11 million years after solar system formation. Copyright © 2017, American Association for the Advancement of Science.

  2. Abundance of carbon and magnesium in the Orion nebula

    International Nuclear Information System (INIS)

    Perinotto, M.; Patriarchi, P.

    1980-01-01

    The Orion nebula has been observed in two positions with IUE (International Ultraviolet Explorer) in the low-resolution mode (approx.7 A) and in the spectral range 1150--3200 A. Emission lines of C II], C III], [O II], and He I have been measured and used to determine what is probably the first reliable abundance of carbon in H II regions. The logarithmic total abundance of carbon is found to be 8.4 close to the solar value. In contrast with the situation in the planetary nebula of similar excitation, IC 418, where the resonance Mg II lambda2800 line is observed to be relatively strong, in the Orion nebula the lambda2800 line is not detectable. an upper limit for the magnesium abundance of the order of 10 times smaller than in the Sun is suggested

  3. Ring-shaped nebulae around FU Orionis stars

    International Nuclear Information System (INIS)

    Goodrich, R.W.

    1987-01-01

    Observational data on the morphology and spectra of the nebulae surrounding V1057 Cyg, V1515 Cyg, and V1735 Cyg stars are presented and studied. The data reveal that V1735 Cyg is more highly reddened than the nebula and the spectra of all three nebulae are from reflection. A simple model for the dust shell is proposed and it is argued that the shells may indicate a relatively advanced evolutionary state for the FU Orionis star. The relation between the shells and the evolution of the stars is examined. The models of Herbig (1977), Mould et al. (1978), Larson (1980), and Hartmann and Kenyon (1985), which are utilized to analyze the FU Orionis outburst phenomenon, are tested. 23 references

  4. The surprising Crab pulsar and its nebula: a review.

    Science.gov (United States)

    Bühler, R; Blandford, R

    2014-06-01

    The Crab nebula and its pulsar (referred to together as 'the Crab') have historically played a central role in astrophysics. True to this legacy, several unique discoveries have been made recently. The Crab was found to emit gamma-ray pulsations up to energies of 400 GeV, beyond what was previously expected from pulsars. Strong gamma-ray flares, of durations of a few days, were discovered from within the nebula, while the source was previously expected to be stable in flux on these time scales. Here we review these intriguing and suggestive developments. In this context we give an overview of the observational properties of the Crab and our current understanding of pulsars and their nebulae.

  5. Facilitating NASA Earth Science Data Processing Using Nebula Cloud Computing

    Science.gov (United States)

    Chen, A.; Pham, L.; Kempler, S.; Theobald, M.; Esfandiari, A.; Campino, J.; Vollmer, B.; Lynnes, C.

    2011-12-01

    Cloud Computing technology has been used to offer high-performance and low-cost computing and storage resources for both scientific problems and business services. Several cloud computing services have been implemented in the commercial arena, e.g. Amazon's EC2 & S3, Microsoft's Azure, and Google App Engine. There are also some research and application programs being launched in academia and governments to utilize Cloud Computing. NASA launched the Nebula Cloud Computing platform in 2008, which is an Infrastructure as a Service (IaaS) to deliver on-demand distributed virtual computers. Nebula users can receive required computing resources as a fully outsourced service. NASA Goddard Earth Science Data and Information Service Center (GES DISC) migrated several GES DISC's applications to the Nebula as a proof of concept, including: a) The Simple, Scalable, Script-based Science Processor for Measurements (S4PM) for processing scientific data; b) the Atmospheric Infrared Sounder (AIRS) data process workflow for processing AIRS raw data; and c) the GES-DISC Interactive Online Visualization ANd aNalysis Infrastructure (GIOVANNI) for online access to, analysis, and visualization of Earth science data. This work aims to evaluate the practicability and adaptability of the Nebula. The initial work focused on the AIRS data process workflow to evaluate the Nebula. The AIRS data process workflow consists of a series of algorithms being used to process raw AIRS level 0 data and output AIRS level 2 geophysical retrievals. Migrating the entire workflow to the Nebula platform is challenging, but practicable. After installing several supporting libraries and the processing code itself, the workflow is able to process AIRS data in a similar fashion to its current (non-cloud) configuration. We compared the performance of processing 2 days of AIRS level 0 data through level 2 using a Nebula virtual computer and a local Linux computer. The result shows that Nebula has significantly

  6. Layers in the Central Orion Nebula

    Science.gov (United States)

    O'Dell, C. R.

    2018-04-01

    The existence of multiple layers in the inner Orion Nebula has been revealed using data from an Atlas of spectra at 2″ and 12 km s-1 resolution. These data were sometimes grouped over Samples of 10″×10″ to produce high Signal to Noise spectra and sometimes grouped into sequences of pseudo-slit Spectra of 12{^''.}8 - 39″width for high spatial resolution studies. Multiple velocity systems were found: V_{MIF} traces the Main Ionization Front (MIF), V_{scat} arises from back-scattering of V_{MIF} emission by particles in the background Photon Dissociation Region (PDR), V_{low} is an ionized layer in front of the MIF and if it is the source of the stellar absorption lines seen in the Trapezium stars, it must lie between the foreground Veil and those stars, V_{new,[O III]} may represent ionized gas evaporating from the Veil away from the observer. There are features such as the Bright Bar where variations of velocities are due to changing tilts of the MIF, but velocity changes above about 25″ arise from variations in velocity of the background PDR. In a region 25″ ENE of the Orion-S Cloud one finds dramatic changes in the [O III] components, including the signals from the V_{low,[O III]} and V_{MIF,[O III]} becoming equal, indicating shadowing of gas from stellar photons of >24.6 eV. This feature is also seen in areas to the west and south of the Orion-S Cloud.

  7. Ultraviolet imaging of planetary nebulae with GALEX

    Science.gov (United States)

    Bianchi, Luciana; Thilker, David

    2018-05-01

    Over four hundred Galactic Planetary Nebulae (PNe) have been imaged by GALEX in two ultraviolet (UV) bands, far-UV (FUV, 1344-1786 Å, λ _{eff}= 1528 Å) and near-NUV (NUV, 1771-2831 Å, λ _{eff} = 2271 Å). We present examples of extended PNe, for which UV spectroscopy is also available, to illustrate the variety in UV morphology and color, which reflects ionization conditions. The depth of the GALEX imaging varies from flux ≈ 0.4/5× 10 ^{-18} ergs cm^{-2} s^{-1} Å^{-1} \\square ^'' -1} (FUV/NUV) for exposures of the order of ˜ 100 seconds, typical of the survey with the largest area coverage, to ˜ 0.3/8.3× 10^{-19} ergs cm^{-2} s^{-1} Å^{-1} \\square ^'' -1} (FUV/NUV) for ˜ 1500 sec exposures, typical of the second largest survey (see Bianchi in Astrophys. Space Sci. 320:11, 2009; Bianchi et al. in Adv. Space Res. 53:900, 2014). GALEX broad-band FUV and NUV fluxes include nebular emission lines and in some cases nebular continuum emission. The sensitivity of the GALEX instrument and the low sky background, especially in FUV, enable detection and mapping of very faint ionization regions and fronts, including outermost wisps and bow shocks. The FUV-NUV color of the central star provides a good indication of its T_{eff}, because the GALEX FUV-NUV color is almost reddening-free for Milky Way type dust (Bianchi et al. in Astrophys. J. Suppl. Ser. 230:24, 2017; Bianchi in Astrophys. Space Sci. 335:51, 2011, Bianchi in Astrophys. Space Sci. 354:103, 2014) and it is more sensitive to hot temperatures than optical colors.

  8. Asymmetric Planetary Nebulae VI: the conference summary

    Science.gov (United States)

    De Marco, O.

    2014-04-01

    The Asymmetric Planetary Nebulae conference series, now in its sixth edition, aims to resolve the shaping mechanism of PN. Eighty percent of PN have non spherical shapes and during this conference the last nails in the coffin of single stars models for non spherical PN have been put. Binary theories abound but observational tests are lagging. The highlight of APN6 has been the arrival of ALMA which allowed us to measure magnetic fields on AGB stars systematically. AGB star halos, with their spiral patterns are now connected to PPN and PN halos. New models give us hope that binary parameters may be decoded from these images. In the post-AGB and pre-PN evolutionary phase the naked post-AGB stars present us with an increasingly curious puzzle as complexity is added to the phenomenologies of objects in transition between the AGB and the central star regimes. Binary central stars continue to be detected, including the first detection of longer period binaries, however a binary fraction is still at large. Hydro models of binary interactions still fail to give us results, if we make an exception for the wider types of binary interactions. More promise is shown by analytical considerations and models driven by simpler, 1D simulations such as those carried out with the code MESA. Large community efforts have given us more homogeneous datasets which will yield results for years to come. Examples are the ChanPlaN and HerPlaNe collaborations that have been working with the Chandra and Herschel space telescopes, respectively. Finally, the new kid in town is the intermediate-luminosity optical transient, a new class of events that may have contributed to forming several peculiar PN and pre-PN.

  9. Do stellar and nebular abundances in the Cocoon nebula agree?

    Science.gov (United States)

    García-Rojas, J.; Simón-Díaz, S.; Esteban, C.

    2015-05-01

    The Cocoon nebula is an apparently spherical Galactic HII region ionized by a single star (BD+46 3474). This nebula seems to be appropriate to investigate the chemical behavior of oxygen and other heavy elements from two different points of view: a detailed analysis of the chemical content of the ionized gas through nebular spectrophotometry and a detailed spectroscopic analysis of the spectrum of the ionizing star using the state-of-the-art stellar atmosphere modelling. In this poster we present the results from a set of high-quality observations, from 2m-4m class telescopes, including the optical spectrum of the ionizing star BD+46 3474, along with long-slit spatially resolved spectroscopy of the nebula. We have used state-of-the-art stellar atmosphere codes to determine stellar parameters and the chemical content of several heavy elements. Traditional nebular techniques along with updated atomic data have been used to compute gaseous abundances of O, N and S in the Cocoon nebula. Thanks to the low ionization degree of the nebula, we could determine total abundances directly from observable ions (no ionization correction factors were needed) for three of the analyzed elements (O, S, and N). The derived stellar and nebular abundances are compared and the influence of the possible presence of the so-called temperature fluctuations on the nebula is discussed. The results of this study are presented in more detail in García-Rojas, Simón-Díaz & Esteban 2014, A&A, 571, A93.

  10. Binarity and the Abundance Discrepancy Problem in Planetary Nebulae

    Science.gov (United States)

    Corradi, Romano L. M.; García-Rojas, Jorge; Jones, David; Rodríguez-Gil, Pablo

    2015-04-01

    The discrepancy between abundances computed using optical recombination lines and collisionally excited lines is a major unresolved problem in nebular astrophysics. Here, we show that the largest abundance discrepancies are reached in planetary nebulae with close binary central stars. We illustrate this using deep spectroscopy of three nebulae with a post common-envelope (CE) binary star. Abell 46 and Ou 5 have O2+/H+ abundance discrepancy factors larger than 50, and as high as 300 in the inner regions of Abell 46. Abell 63 has a smaller discrepancy factor around 10, which is still above the typical values in ionized nebulae. Our spectroscopic analysis supports previous conclusions that, in addition to “standard” hot ({{T}e} ˜ 104 K) gas, there exists a colder ({{T}e} ˜ 103 K), ionized component that is highly enriched in heavy elements. These nebulae have low ionized masses, between 10-3 and 10-1 M⊙ depending on the adopted electron densities and temperatures. Since the much more massive red giant envelope is expected to be entirely ejected in the CE phase, the currently observed nebulae would be produced much later, during post-CE mass loss episodes when the envelope has already dispersed. These observations add constraints to the abundance discrepancy problem. We revise possible explanations. Some explanations are naturally linked to binarity such as, for instance, high-metallicity nova ejecta, but it is difficult at this stage to depict an evolutionary scenario consistent with all of the observed properties. We also introduce the hypothesis that these nebulae are the result of tidal destruction, accretion, and ejection of Jupiter-like planets.

  11. Excimer laser superficial keratectomy for proud nebulae in keratoconus.

    Science.gov (United States)

    Moodaley, L; Liu, C; Woodward, E G; O'Brart, D; Muir, M K; Buckley, R

    1994-06-01

    Contact lens intolerance in keratoconus may be due to the formation of a proud nebula at or near the apex of the cone. Excimer laser superficial keratectomy was performed as an outpatients with proud nebulae as treatment patients with proud nebulae as treatment for their contact lens intolerance. The mean period of contact lens wear before the development of intolerance was 13.4 years (range 2 to 27 years). Following the development of intolerance, three patients abandoned contact lens wear in the affected eye while the remainder experienced a reduction in comfortable wearing time (mean = 3.75 hours; range: 0-14 hours). All patients had good potential Snellen visual acuity with a contact lens of 6/9 (nine eyes) and 6/12 (one eye). The proud nebulae were directly ablated with a 193 nm ArF excimer laser using a 1 mm diameter beam. Between 100-150 pulses were sufficient to ablate the raised area. Patients experienced no pain during the procedure and reported minimal discomfort postoperatively. In all cases flattening of the proud nebulae was achieved. Seven patients were able to resume regular contact lens wear (mean wearing time = 10.17 hours; range 8 to 16 hours). In three patients, resumption of contact lens wear was unsuccessful because of cone steepness. All patients achieved postoperative Snellen visual acuity of 6/12 or better with a contact lens. Four patients experienced a loss of one line in Snellen acuity. The mean follow up period was 8.3 months (range 2 to 17 months). Excimer laser superficial keratectomy is a useful technique for the treatment of contact lens intolerance caused by proud nebulae in patients with keratoconus. Penetrating keratoplasty is thus avoided.

  12. Experimental simulations of sulfide formation in the solar nebula.

    Science.gov (United States)

    Lauretta, D S; Lodders, K; Fegley, B

    1997-07-18

    Sulfurization of meteoritic metal in H2S-H2 gas produced three different sulfides: monosulfide solid solution [(Fe,Ni)1-xS], pentlandite [(Fe,Ni)9-xS8], and a phosphorus-rich sulfide. The composition of the remnant metal was unchanged. These results are contrary to theoretical predictions that sulfide formation in the solar nebula produced troilite (FeS) and enriched the remaining metal in nickel. The experimental sulfides are chemically and morphologically similar to sulfide grains in the matrix of the Alais (class CI) carbonaceous chondrite, suggesting that these meteoritic sulfides may be condensates from the solar nebula.

  13. Particle Acceleration in Pulsar Wind Nebulae: PIC Modelling

    Science.gov (United States)

    Sironi, Lorenzo; Cerutti, Benoît

    We discuss the role of PIC simulations in unveiling the origin of the emitting particles in PWNe. After describing the basics of the PIC technique, we summarize its implications for the quiescent and the flaring emission of the Crab Nebula, as a prototype of PWNe. A consensus seems to be emerging that, in addition to the standard scenario of particle acceleration via the Fermi process at the termination shock of the pulsar wind, magnetic reconnection in the wind, at the termination shock and in the Nebula plays a major role in powering the multi-wavelength signatures of PWNe.

  14. A radio search for planetary nebulae near the galactic center

    International Nuclear Information System (INIS)

    Isaacman, R.B.

    1980-01-01

    Because of galactic center is a hostile environment, and because planetaries are weak radio emitters, it is not clear a priori that one expects to detect any planetary nebulae at all in the nuclear region of the Galaxy. Therefore the expected lifetime and flux density distribution of galactic center nebulae is considered. The principal observational results from the Westerbork data, and the results of some pilot observations with the Very Large Array, which were intended to distinguish planetaries from other radio sources on an individual basis are given. (Auth.)

  15. Facilitating NASA Earth Science Data Processing Using Nebula Cloud Computing

    Science.gov (United States)

    Pham, Long; Chen, Aijun; Kempler, Steven; Lynnes, Christopher; Theobald, Michael; Asghar, Esfandiari; Campino, Jane; Vollmer, Bruce

    2011-01-01

    Cloud Computing has been implemented in several commercial arenas. The NASA Nebula Cloud Computing platform is an Infrastructure as a Service (IaaS) built in 2008 at NASA Ames Research Center and 2010 at GSFC. Nebula is an open source Cloud platform intended to: a) Make NASA realize significant cost savings through efficient resource utilization, reduced energy consumption, and reduced labor costs. b) Provide an easier way for NASA scientists and researchers to efficiently explore and share large and complex data sets. c) Allow customers to provision, manage, and decommission computing capabilities on an as-needed bases

  16. Infrared studies of galactic nebulae. IV - Continuum and line radiation from planetary nebulae.

    Science.gov (United States)

    Gillett, F. C.; Merrill, K. M.; Stein, W. A.

    1972-01-01

    Observations are reported of the detection of IR radiation from several planetary nebulae not previously known to be radiating at these wavelengths. Broad spectral bandwidth observations indicate that ir radiation in excess of that expected from atomic processes is a common phenomenon among these objects. Investigations with narrow spectral bandwidth show that in a few cases the energy in the 10.52-micron line is a significant fraction of the total energy observed in the broad-band measurements and in other cases a relatively small fraction of the total radiation. Other observations on two sources with narrow spectral bandwidth adjacent to the 10.52-micron line indicate that at these wavelengths a true continuum of radiation exists as well as lines. The results are discussed in relation to visual and radio-wavelength data.

  17. Bipolar polygenic loading and bipolar spectrum features in major depressive disorder

    NARCIS (Netherlands)

    Wiste, Anna; Robinson, Elise B.; Milaneschi, Yuri; Meier, Sandra; Ripke, Stephan; Clements, Caitlin C.; Fitzmaurice, Garrett M.; Rietschel, Marcella; Penninx, Brenda W.; Smoller, Jordan W.; Perlis, Roy H.

    Objectives Family and genetic studies indicate overlapping liability for major depressive disorder and bipolar disorder. The purpose of the present study was to determine whether this shared genetic liability influences clinical presentation. Methods A polygenic risk score for bipolar disorder,

  18. International Ultraviolet Explorer satellite observations of seven high-excitation planetary nebulae.

    Science.gov (United States)

    Aller, L H; Keyes, C D

    1980-03-01

    Observations of seven high-excitation planetary nebulae secured with the International Ultraviolet Explorer (IUE) satellite were combined with extensive ground-based data to obtain electron densities, gas kinetic temperatures, and ionic concentrations. We then employed a network of theoretical model nebulae to estimate the factors by which observed ionic concentrations must be multiplied to obtain elemental abundances. Comparison with a large sample of nebulae for which extensive ground-based observations have been obtained shows nitrogen to be markedly enhanced in some of these objects. Possibly most, if not all, high-excitation nebulae evolve from stars that have higher masses than progenitors of nebulae of low-to-moderate excitation.

  19. A new survey of nebulae around Galactic Wolf-Rayet stars in the northern sky

    Science.gov (United States)

    Miller, Grant J.; Chu, You-Hua

    1993-01-01

    Interference filter CCD images have been obtained in H-alpha and forbidden O III 5007 A for 62 Wolf-Rayet (W-R) stars, representing a complete survey of nebulae around Galactic W-R stars in the northern sky. We find probable new ring nebulae around W-R stars number 113, 116 and 132, and possible new ring nebulae around W-R stars number 133 and 153. All survey images showing nebulosities around W-R stars are presented in this paper. New physical information is derived from the improved images of known ring nebulae. The absence of ring nebulae around most W-R stars is discussed.

  20. A new planetary nebula in the outer reaches of the Galaxy

    DEFF Research Database (Denmark)

    Viironen, K.; Mampaso, A.; L. M. Corradi, R.

    2011-01-01

    of a new planetary nebula towards the Anticentre direction, IPHASX J052531.19+281945.1 (PNG 178.1-04.0), is presented. The planetary nebula was discovered from the IPHAS survey. Long-slit follow-up spectroscopy was carried out to confirm its planetary nebula nature and to calculate its physical...... and chemical characteristics. The newly discovered planetary nebula turned out to be located at a very large galactocentric distance (D_GC=20.8+-3.8 kpc), larger than any previously known planetary nebula with measured abundances. Its relatively high oxygen abundance (12+log(O/H) = 8.36+-0.03) supports...

  1. VizieR Online Data Catalog: MIPS 24um nebulae (Gvaramadze+, 2010)

    Science.gov (United States)

    Gvaramadze, V. V.; Kniazev, A. Y.; Fabrika, S.

    2011-03-01

    Massive evolved stars lose a large fraction of their mass via copious stellar wind or instant outbursts. During certain evolutionary phases, they can be identified by the presence of their circumstellar nebulae. In this paper, we present the results of a search for compact nebulae (reminiscent of circumstellar nebulae around evolved massive stars) using archival 24um data obtained with the Multiband Imaging Photometer for Spitzer. We have discovered 115 nebulae, most of which bear a striking resemblance to the circumstellar nebulae associated with luminous blue variables (LBVs) and late WN-type (WNL) Wolf-Rayet (WR) stars in the Milky Way and the Large Magellanic Cloud (LMC). (1 data file).

  2. Planetary Nebulae in the Solar Neighbourhood: Statistics, Distance Scale and Luminosity Function

    Science.gov (United States)

    Frew, David J.

    2008-07-01

    An accurate census of the nearest planetary nebulae (PNe) is needed for calculations of the total number, space density, scale height, and birth rate of PNe in the Galaxy, to understand the dynamics of an evolving nebula and its relationship to the cooling history of the central star, and also to provide an unbiased sample to investigate the frequency of binary central stars and their role in the formation and shaping of these objects. This study presents the most refined volume-limited survey of PNe known to date. Integrated H-alpha fluxes for over 400 mostly evolved PNe are presented, based primarily on data from the Southern H-alpha Sky Survey Atlas (SHASSA) and the Virginia Tech Spectral-Line Survey (VTSS). Aperture photometry on the digital images was performed to extract H-alpha+[NII] fluxes. The [NII] contribution was then de-convolved using literature data, new data from slit spectra, or spectrophotometric data from the Wisconsin H-Alpha Mapper (WHAM) also obtained as part of this project. Comparison with previous work shows that the flux scale presented here has no significant zero-point error. The H-alpha fluxes are used to determine new Zanstra temperatures for those PNe with accurate central star photometry, calculating surface-brightness distances for each PN in the sample, and in conjunction with accurate [OIII] fluxes, new absolute PN magnitudes for delineating the faint end of the PN luminosity function. A spectroscopic survey of a range of MASH PNe is also presented. New emission-line intensities for 60 PNe are given, including a preliminary discussion of the chemical abundances of this sample. New distances have been determined for a large number of PNe, by either critically examining the literature, or by deriving new extinction and kinematic distances where suitable. For all PNe not amenable to these approaches, distances were estimated from a new H-alpha surface brightness-radius (SB-r) relation. The Hα SB-r relation covers >6 dex in SB, and

  3. A 'FIREWORK' OF H2 KNOTS IN THE PLANETARY NEBULA NGC 7293 (THE HELIX NEBULA)

    International Nuclear Information System (INIS)

    Matsuura, M.; Speck, A. K.; McHunu, B. M.; Tanaka, I.; Wright, N. J.; Viti, S.; Wesson, R.; Smith, M. D.; Zijlstra, A. A.

    2009-01-01

    We present a deep and wide field-of-view (4' x 7') image of the planetary nebula (PN) NGC 7293 (the Helix Nebula) in the 2.12 μm H 2 v = 1 → 0 S(1) line. The excellent seeing (0.''4) at the Subaru Telescope, allows the details of cometary knots to be examined. The knots are found at distances of 2.'2-6.'4 from the central star (CS). At the inner edge and in the inner ring (up to 4.'5 from the CS), the knot often show a 'tadpole' shape, an elliptical head with a bright crescent inside and a long tail opposite to the CS. In detail, there are variations in the tadpole shapes, such as narrowing tails, widening tails, meandering tails, or multipeaks within a tail. In the outer ring (4.'5-6.'4 from the CS), the shapes are more fractured, and the tails do not collimate into a single direction. The transition in knot morphology from the inner edge to the outer ring is clearly seen. The number density of knots governs the H 2 surface brightness in the inner ring: H 2 exists only within the knots. Possible mechanisms which contribute to the shaping of the knots are discussed, including photoionization and streaming motions. A plausible interpretation of our images is that inner knots are being overrun by a faster wind, but that this has not (yet) reached the outer knots. Based on H 2 formation and destruction rates, H 2 gas can survive in knots from formation during the late asymptotic giant branch phase throughout the PN phase. These observations provide new constraints on the formation and evolution of knots, and on the physics of molecular gas embedded within ionized gas.

  4. A "Firework" of H2 Knots in the Planetary Nebula NGC 7293 (The Helix Nebula)

    Science.gov (United States)

    Matsuura, M.; Speck, A. K.; McHunu, B. M.; Tanaka, I.; Wright, N. J.; Smith, M. D.; Zijlstra, A. A.; Viti, S.; Wesson, R.

    2009-08-01

    We present a deep and wide field-of-view (4' × 7') image of the planetary nebula (PN) NGC 7293 (the Helix Nebula) in the 2.12 μm H2 v = 1 → 0 S(1) line. The excellent seeing (0farcs4) at the Subaru Telescope, allows the details of cometary knots to be examined. The knots are found at distances of 2farcm2-6farcm4 from the central star (CS). At the inner edge and in the inner ring (up to 4farcm5 from the CS), the knot often show a "tadpole" shape, an elliptical head with a bright crescent inside and a long tail opposite to the CS. In detail, there are variations in the tadpole shapes, such as narrowing tails, widening tails, meandering tails, or multipeaks within a tail. In the outer ring (4farcm5-6farcm4 from the CS), the shapes are more fractured, and the tails do not collimate into a single direction. The transition in knot morphology from the inner edge to the outer ring is clearly seen. The number density of knots governs the H2 surface brightness in the inner ring: H2 exists only within the knots. Possible mechanisms which contribute to the shaping of the knots are discussed, including photoionization and streaming motions. A plausible interpretation of our images is that inner knots are being overrun by a faster wind, but that this has not (yet) reached the outer knots. Based on H2 formation and destruction rates, H2 gas can survive in knots from formation during the late asymptotic giant branch phase throughout the PN phase. These observations provide new constraints on the formation and evolution of knots, and on the physics of molecular gas embedded within ionized gas. Based on data taken with the Subaru Telescope, National Astronomical Observatory of Japan (proposal ID S07B-054).

  5. Unsplit bipolar pulse forming line

    Science.gov (United States)

    Rhodes, Mark A [Pleasanton, CA

    2011-05-24

    A bipolar pulse forming transmission line module and system for linear induction accelerators having first, second, third, and fourth planar conductors which form a sequentially arranged interleaved stack having opposing first and second ends, with dielectric layers between the conductors. The first and second planar conductors are connected to each other at the first end, and the first and fourth planar conductors are connected to each other at the second end via a shorting plate. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short at the first end a high voltage from the third planar conductor to the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  6. Course of Subthreshold Bipolar Disorder in Youth: Diagnostic Progression from Bipolar Disorder Not Otherwise Specified

    Science.gov (United States)

    Axelson, David A.; Birmaher, Boris; Strober, Michael A.; Goldstein, Benjamin I.; Ha, Wonho; Gill, Mary Kay; Goldstein, Tina R.; Yen, Shirley; Hower, Heather; Hunt, Jeffrey I.; Liao, Fangzi; Iyengar, Satish; Dickstein, Daniel; Kim, Eunice; Ryan, Neal D.; Frankel, Erica; Keller, Martin B.

    2011-01-01

    Objective: To determine the rate of diagnostic conversion from an operationalized diagnosis of bipolar disorder not otherwise specified (BP-NOS) to bipolar I disorder (BP-I) or bipolar II disorder (BP-II) in youth over prospective follow-up and to identify factors associated with conversion. Method: Subjects were 140 children and adolescents…

  7. Expansion patterns and parallaxes for planetary nebulae

    Science.gov (United States)

    Schönberner, D.; Balick, B.; Jacob, R.

    2018-02-01

    Aims: We aim to determine individual distances to a small number of rather round, quite regularly shaped planetary nebulae by combining their angular expansion in the plane of the sky with a spectroscopically measured expansion along the line of sight. Methods: We combined up to three epochs of Hubble Space Telescope imaging data and determined the angular proper motions of rim and shell edges and of other features. These results are combined with measured expansion speeds to determine individual distances by assuming that line of sight and sky-plane expansions are equal. We employed 1D radiation-hydrodynamics simulations of nebular evolution to correct for the difference between the spectroscopically measured expansion velocities of rim and shell and of their respective shock fronts. Results: Rim and shell are two independently expanding entities, driven by different physical mechanisms, although their model-based expansion timescales are quite similar. We derive good individual distances for 15 objects, and the main results are as follows: (i) distances derived from rim and shell agree well; (ii) comparison with the statistical distances in the literature gives reasonable agreement; (iii) our distances disagree with those derived by spectroscopic methods; (iv) central-star "plateau" luminosities range from about 2000 L⊙ to well below 10 000 L⊙, with a mean value at about 5000 L⊙, in excellent agreement with other samples of known distance (Galactic bulge, Magellanic Clouds, and K648 in the globular cluster M 15); (v) the central-star mass range is rather restricted: from about 0.53 to about 0.56 M⊙, with a mean value of 0.55 M⊙. Conclusions: The expansion measurements of nebular rim and shell edges confirm the predictions of radiation-hydrodynamics simulations and offer a reliable method for the evaluation of distances to suited objects. Results of this paper are based on observations made with the NASA/ESA Hubble Space Telescope in Cycle 16 (GO11122

  8. Abundant Solar Nebula Solids in Comets

    Science.gov (United States)

    Messenger, S.; Keller, L. P.; Nakamura-Messenger, K.; Nguyen, A. N.; Clemett, S.

    2016-01-01

    Comets have been proposed to consist of unprocessed interstellar materials together with a variable amount of thermally annealed interstellar grains. Recent studies of cometary solids in the laboratory have shown that comets instead consist of a wide range of materials from across the protoplanetary disk, in addition to a minor complement of interstellar materials. These advances were made possible by the return of direct samples of comet 81P/Wild 2 coma dust by the NASA Stardust mission and recent advances in microscale analytical techniques. Isotopic studies of 'cometary' chondritic porous interplanetary dust particles (CP-IDPs) and comet 81P/Wild 2 Stardust samples show that preserved interstellar materials are more abundant in comets than in any class of meteorite. Identified interstellar materials include sub-micron-sized presolar silicates, oxides, and SiC dust grains and some fraction of the organic material that binds the samples together. Presolar grain abundances reach 1 weight percentage in the most stardust-rich CP-IDPs, 50 times greater than in meteorites. Yet, order of magnitude variations in presolar grain abundances among CP-IDPs suggest cometary solids experienced significant variations in the degree of processing in the solar nebula. Comets contain a surprisingly high abundance of nebular solids formed or altered at high temperatures. Comet 81P/Wild 2 samples include 10-40 micron-sized, refractory Ca- Al-rich inclusion (CAI)-, chondrule-, and ameboid olivine aggregate (AOA)-like materials. The O isotopic compositions of these refractory materials are remarkably similar to their meteoritic counterparts, ranging from 5 percent enrichments in (sup 16) O to near-terrestrial values. Comet 81P/Wild 2 and CP-IDPs also contain abundant Mg-Fe crystalline and amorphous silicates whose O isotopic compositions are also consistent with Solar System origins. Unlike meteorites, that are dominated by locally-produced materials, comets appear to be composed of

  9. The first frost in the Pipe Nebula

    Science.gov (United States)

    Goto, Miwa; Bailey, Jeffrey D.; Hocuk, Seyit; Caselli, Paola; Esplugues, Gisela B.; Cazaux, Stephanie; Spaans, Marco

    2018-02-01

    Context. Spectroscopic studies of ices in nearby star-forming regions indicate that ice mantles form on dust grains in two distinct steps, starting with polar ice formation (H2O rich) and switching to apolar ice (CO rich). Aims: We test how well the picture applies to more diffuse and quiescent clouds where the formation of the first layers of ice mantles can be witnessed. Methods: Medium-resolution near-infrared spectra are obtained toward background field stars behind the Pipe Nebula. Results: The water ice absorption is positively detected at 3.0 μm in seven lines of sight out of 21 sources for which observed spectra are successfully reduced. The peak optical depth of the water ice is significantly lower than those in Taurus with the same AV. The source with the highest water-ice optical depth shows CO ice absorption at 4.7 μm as well. The fractional abundance of CO ice with respect to water ice is 16-6+7%, and about half as much as the values typically seen in low-mass star-forming regions. Conclusions: A small fractional abundance of CO ice is consistent with some of the existing simulations. Observations of CO2 ice in the early diffuse phase of a cloud play a decisive role in understanding the switching mechanism between polar and apolar ice formation. Based on data collected by SpeX at the Infrared Telescope Facility, which is operated by the University of Hawaii under contract NNH14CK55B with the National Aeronautics and Space Administration.Based also on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.The final reduced spectra (FITS format) are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/610

  10. INFRARED STUDY OF FULLERENE PLANETARY NEBULAE

    International Nuclear Information System (INIS)

    García-Hernández, D. A.; Acosta-Pulido, J. A.; Manchado, A.; Villaver, E.; García-Lario, P.; Stanghellini, L.; Shaw, R. A.; Cataldo, F.

    2012-01-01

    We present a study of 16 planetary nebulae (PNe) where fullerenes have been detected in their Spitzer Space Telescope spectra. This large sample of objects offers a unique opportunity to test conditions of fullerene formation and survival under different metallicity environments because we are analyzing five sources in our own Galaxy, four in the Large Magellanic Cloud (LMC), and seven in the Small Magellanic Cloud (SMC). Among the 16 PNe studied, we present the first detection of C 60 (and possibly also C 70 ) fullerenes in the PN M 1–60 as well as of the unusual ∼6.6, 9.8, and 20 μm features (attributed to possible planar C 24 ) in the PN K 3–54. Although selection effects in the original samples of PNe observed with Spitzer may play a potentially significant role in the statistics, we find that the detection rate of fullerenes in C-rich PNe increases with decreasing metallicity (∼5% in the Galaxy, ∼20% in the LMC, and ∼44% in the SMC) and we interpret this as a possible consequence of the limited dust processing occurring in Magellanic Cloud (MC) PNe. CLOUDY photoionization modeling matches the observed IR fluxes with central stars that display a rather narrow range in effective temperature (∼30,000-45,000 K), suggesting a common evolutionary status of the objects and similar fullerene formation conditions. Furthermore, the data suggest that fullerene PNe likely evolve from low-mass progenitors and are usually of low excitation. We do not find a metallicity dependence on the estimated fullerene abundances. The observed C 60 intensity ratios in the Galactic sources confirm our previous finding in the MCs that the fullerene emission is not excited by the UV radiation from the central star. CLOUDY models also show that line- and wind-blanketed model atmospheres can explain many of the observed [Ne III]/[Ne II] ratios using photoionization, suggesting that possibly the UV radiation from the central star, and not shocks, is triggering the decomposition

  11. Observational study of Herbig-Haro nebulae

    International Nuclear Information System (INIS)

    Brugel, E.W.

    1981-01-01

    Spectrophotometric data have been obtained for twelve Herbig-Haro nebulae with the multichannel spectrometer on the Mt. Palomar 5.08 meter telescope and with the image intensified dissector scanner on the Kitt Peak 2.13 meter telescope. Energy distributions of the continuous spectra of the Herbig-Haro objects H-H 1 (NW), H-H 2A, H-H 2G, H-H 2H, H-H 24A and H-H 32 have been determined in the wavelength range 3300 to 8000A. The signal-to-noise ratio has been improved in comparison to an earlier attempt to measure the continuum in H-H 1 and H-H 2H. Reddening corrections are based on Miller's [SII] method. The [FeII] emission line spectra have also been utilized as a secondary method for determining the interstellar reddening. In all continua the flux F/sub lambda/ increases rapidly with decreasing wavelength after the small scale structure has been averaged out. A power law interpolation F/sub lambda/ proportional lambda/sup -n/ demonstrates that for all observed H-H objects n lies in the range between 2.04 (H-H 2A, H-H 2H) and 2.92 (H-H 32). The relation of these results to recent I.U.E. observations of H-H 1 is discussed. It is also found that the ratio of the total optical continuum flux to Hβ flux is almost the same for all observed H-H objects with the sole exception of H-H 24A in which the continuum is considerably stronger than in other objects. This fact leads to difficulties in the usual dust scattering hypothesis for the interpretation of H-H continua. It is argued, if these energy distributions are really due to dust scattering in stellar continua as has been usually assumed, the original source must be a hot object and cannot be a T Tauri star.An interpretation in terms of transition radiation (as suggested by Gurzadyan) does not seem to be possible because the observed rise of F/sub lambda/ towards the ultraviolet is too steep

  12. Bipolar (spectrum) disorder and mood stabilization: standing at the crossroads?

    OpenAIRE

    De Fruyt, Jurgen; Demyttenaere, Koen

    2007-01-01

    Diagnosis and treatment of bipolar disorder has long been a neglected discipline. Recent years have shown an upsurge in bipolar research. When compared to major depressive disorder, bipolar research still remains limited and more expert based than evidence based. In bipolar diagnosis the focus is shifting from classic mania to bipolar depression and hypomania. There is a search for bipolar signatures in symptoms and course of major depressive episodes. The criteria for hypomania are softened,...

  13. [Bipolar disorders in DSM-5].

    Science.gov (United States)

    Severus, E; Bauer, M

    2014-05-01

    In spring 2013 the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) edited by the American Psychiatric Association was published. The DSM-5 has also brought some important changes regarding bipolar disorders. The goal of this manuscript is to review the novelties in DSM-5 and to evaluate the implications of these changes. The diagnostic criteria as well as the additional remarks provided in the running text of DSM-5 were carefully appraised. For the first time diagnostic criteria are provided for disorders which up to now have been considered as subthreshold bipolar disorders. Furthermore, mixed episodes were eliminated and instead a mixed specifier was introduced. An increase in goal-directed activity/energy is now one of the obligatory symptoms for a (hypo)manic episode. Diagnostic guidance is provided as to when a (hypo)manic episode that has developed during treatment with an antidepressant has to be judged to be causally related to antidepressants and when this episode has only occurred coincidentally with antidepressant use. While some of the novelties are clearly useful, e.g. addition of increased goal-directed activity/energy as obligatory symptom for (hypo)manic episodes, this remains to be demonstrated for others, such as the definition of various subthreshold bipolar disorders.

  14. Virginia Woolf, neuroprogression, and bipolar disorder

    Directory of Open Access Journals (Sweden)

    Manuela V. Boeira

    2016-01-01

    Full Text Available Family history and traumatic experiences are factors linked to bipolar disorder. It is known that the lifetime risk of bipolar disorder in relatives of a bipolar proband are 5-10% for first degree relatives and 40-70% for monozygotic co-twins. It is also known that patients with early childhood trauma present earlier onset of bipolar disorder, increased number of manic episodes, and more suicide attempts. We have recently reported that childhood trauma partly mediates the effect of family history on bipolar disorder diagnosis. In light of these findings from the scientific literature, we reviewed the work of British writer Virginia Woolf, who allegedly suffered from bipolar disorder. Her disorder was strongly related to her family background. Moreover, Virginia Woolf was sexually molested by her half siblings for nine years. Her bipolar disorder symptoms presented a pernicious course, associated with hospitalizations, suicidal behavioral, and functional impairment. The concept of neuroprogression has been used to explain the clinical deterioration that takes places in a subgroup of bipolar disorder patients. The examination of Virgina Woolf’s biography and art can provide clinicians with important insights about the course of bipolar disorder.

  15. Bipolar Disorder and Obsessive Compulsive Disorder Comorbidity

    Directory of Open Access Journals (Sweden)

    Necla Keskin

    2014-08-01

    Full Text Available The comorbidity of bipolar disorder and anxiety disorders is a well known concept. Obsessive-compulsive disorder is the most commonly seen comorbid anxiety disorder in bipolar patients. Some genetic variants, neurotransmitters especially serotonergic systems and second-messenger systems are thought to be responsible for its etiology. Bipolar disorder alters the clinical aspects of obsessive compulsive disorder and is associated with poorer outcome. The determination of comorbidity between bipolar disorder and obsessive compulsive disorder is quite important for appropriate clinical management and treatment. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2014; 6(4.000: 429-437

  16. [Lithium and anticonvulsants in bipolar depression].

    Science.gov (United States)

    Samalin, L; Nourry, A; Llorca, P-M

    2011-12-01

    For decades, lithium and anticonvulsants have been widely used in the treatment of bipolar disorder. Their efficacy in the treatment of mania is recognized. These drugs have been initially evaluated in old and methodologically heterogeneous studies. Their efficacy in bipolar depression has not always been confirmed in more recent and methodologically more reliable studies. Thus, lithium's efficacy as monotherapy was challenged by the study of Young (2008) that showed a lack of efficacy compared with placebo in the treatment of bipolar depression. In two recent meta-analyses, valproate has shown a modest efficacy in the treatment of bipolar depression. As for lithium, valproate appeared to have a larger antimanic effect for acute phase and prophylaxis of bipolar disorder. In contrast, lamotrigine is more effective on the depressive pole of bipolar disorder with better evidence for the prevention of depressive recurrences. The guidelines include these recent studies and recommend lamotrigine as a first-line treatment of bipolar depression and for maintenance treatment. Because of more discordant data concerning lithium and valproate, these two drugs are placed either as first or as second line treatment of bipolar depression. The different safety/efficacy ratios of mood stabilizers underlie the complementarity and the importance of combination between them, or with some second-generation antipsychotics, in the treatment of patients with bipolar disorder. Copyright © 2011 L’Encéphale. Published by Elsevier Masson SAS.. All rights reserved.

  17. Late Onset Bipolar Disorder: Case Report

    Directory of Open Access Journals (Sweden)

    Filipa Araújo

    2016-07-01

    Full Text Available Background: Bipolar disorder affects approximately 1% of the population, with diagnosis often being made during late adolescence and early adulthood, and only rarely (0.1% in the elderly. Late onset bipolar disorder in the elderly has a impact on the nature and course of bipolar disorder. Aims: The authors report a case of bipolar disorder emerging in late life  (76years old with no cleary identified organic cause. Conclusion: This case highlights the importance of a broad differential diagnosis and pharmacologic management when approaching new-onset manic/depressive symptoms among geriatric patients.

  18. Dysfunctional gaze processing in bipolar disorder

    Directory of Open Access Journals (Sweden)

    Cristina Berchio

    2017-01-01

    The present study provides neurophysiological evidence for abnormal gaze processing in BP and suggests dysfunctional processing of direct eye contact as a prominent characteristic of bipolar disorder.

  19. The central star of the Planetary Nebula NGC 6537

    NARCIS (Netherlands)

    Pottasch, [No Value

    2000-01-01

    The fact that Space Telescope WFPC2 images of the planetary nebula NGC 6537 fail to show the central star is used to derive a limit to its magnitude: it is fainter than a magnitude of 22.4 in the visible. This is used to derive a lower limit to the temperature of the star. The Zanstra temperature is

  20. Ultraviolet spectroscopy of planetary nebulae in the Magellanic Clouds

    International Nuclear Information System (INIS)

    Maran, S.P.; Aller, L.H.; Gull, T.R.; Stecher, T.P.

    1982-01-01

    Ultraviolet spectra of three high excitation planetary nebulae in the Magellanic Clouds (LMC P40, SMC N2, SMC N5) were obtained with the International Ultraviolet Explorer. The results are analyzed together with new visual wavelength spectrophotometry of LMC P40 and published data on SMC N2 and SMC N5 to investigate chemical composition and in particular to make the first reliable estimates of the carbon abundance in extragalactic planetary nebulae. Although carbon is at most only slightly less abundant in the LMC and SMC planetary nebulae than in galactic planetaries, it is almost 40 times more abundant in the SMC planetaries than in the SMC interstellar medium, and is about 6 times more abundant in the LMC planetary than in the LMC interstellar medium. According to our limited sample, the net result of carbon synthesis and convective dredgeup in the progenitors of planetary nebulae, as reflected in the nebular carbon abundance, is roughly the same in the Galaxy, the LMC, and the SMC

  1. Preferrential Concentration of Particles in Protoplanetary Nebula Turbulence

    Science.gov (United States)

    Hartlep, Thomas; Cuzzi, Jeffrey N.

    2015-01-01

    Preferential concentration in turbulence is a process that causes inertial particles to cluster in regions of high strain (in-between high vorticity regions), with specifics depending on their stopping time or Stokes number. This process is thought to be of importance in various problems including cloud droplet formation and aerosol transport in the atmosphere, sprays, and also in the formation of asteroids and comets in protoplanetary nebulae. In protoplanetary nebulae, the initial accretion of primitive bodies from freely-floating particles remains a problematic subject. Traditional growth-by-sticking models encounter a formidable "meter-size barrier" [1] in turbulent nebulae. One scenario that can lead directly from independent nebula particulates to large objects, avoiding the problematic m-km size range, involves formation of dense clumps of aerodynamically selected, typically mm-size particles in protoplanetary turbulence. There is evidence that at least the ordinary chondrite parent bodies were initially composed entirely of a homogeneous mix of such particles generally known as "chondrules" [2]. Thus, while it is arcane, turbulent preferential concentration acting directly on chondrule size particles are worthy of deeper study. Here, we present the statistical determination of particle multiplier distributions from numerical simulations of particle-laden isotopic turbulence, and a cascade model for modeling turbulent concentration at lengthscales and Reynolds numbers not accessible by numerical simulations. We find that the multiplier distributions are scale dependent at the very largest scales but have scale-invariant properties under a particular variable normalization at smaller scales.

  2. Hard X-ray Variations in the Crab Nebula

    Science.gov (United States)

    Wilson-Hodge, Colleen A.; Cherry, M. L.; Case, G. L.; Baumgartner, W. H.; Beklen, E.; Bhat, P. N.; Briggs, M. S.; Camero-Arranz, A.; Connaughton, V.; Finger, M. H.; hide

    2013-01-01

    In the first two years of science operations of the Fermi Gamma-ray Burst Monitor (GBM), August 2008 to August 2010, approximately 7% (70 mcrab) decline was discovered in the overall Crab Nebula flux in the 15 - 50 keV band, measured with the Earth occultation technique. This decline was independently confirmed with four other instruments: the RXTE/PCA, Swift/BAT, INTEGRAL/IBIS, and INTEGRAL/SPI. The pulsed flux measured with RXTE/PCA from 1999-2010 was consistent with the pulsar spin-down, indicating that the observed changes were nebular. From 2001 to 2010, the Crab nebula flux measured with RXTE/ PCA was particularly variable, changing by up to approximately 3.5% per year in the 15-50 keV band. These variations were confirmed with INTEGRAL/SPI starting in 2003, Swift/BAT starting in 2005, and Fermi GBM starting in 2008. Before 2001 and since 2010, the Crab nebula flux has appeared more stable, varying by less than 2% per year. I will present updated light curves in multiple energy bands for the Crab Nebula, including recent data from Fermi GBM, Swift/BAT, INTEGRAL and MAXI, and a 16-year long light curve from RXTE/PCA.

  3. Unusual motions in the Wolf-Rayet nebula NGC 6888

    International Nuclear Information System (INIS)

    Johnson, P.G.; Songsathaporn, R.

    1981-01-01

    A systematic survey of the velocity structure within the Wolf-Rayet ring nebula NGC 6888 has been undertaken by making observations of the [N II] line profiles. They reveal a hitherto undetected and particularly unusual velocity structure with three of the brightest portions of the circumference of this ring exhibiting triple line components. Possible models to explain these observations are discussed. (author)

  4. Multibaseline Observations of the Occultation of Crab Nebula by the ...

    Indian Academy of Sciences (India)

    tribpo

    Observations of the radio source Crab Nebula were made at the time of transit during. June 1986 and 1987. The fringe amplitude V(S) for a baseline S was calibrated using the corresponding baseline fringe amplitude of radio source 3C123 or 3C134 and normalised to the preoccultation value V(O). Normalised fringe ...

  5. Crab Nebula Variations in Hard X-rays

    Science.gov (United States)

    Wilson-Hodge, Colleen A.

    2012-01-01

    The Crab Nebula was surprisingly variable from 2001-2010, with less variability before 2001 and since mid-2010. We presented evidence for spectral softening from RXTE, Swift/BAT, and Fermi GBM during the mid-2008-2010 flux decline. We see no clear connections between the hard X-ray variations and the GeV flares

  6. OpenNebula KVM SR-IOV driver

    CSIR Research Space (South Africa)

    Macleod, D

    2013-05-01

    Full Text Available With the recent release of an OFED which supports SR-IOV on Infiniband HCAs it is now possible to use verbs from inside a VM. This VMM driver supports these Infiniband HCAs, and any other SR-IOV network device, in OpenNebula....

  7. Modern techniques in galaxy kinematics : Results from planetary nebula spectroscopy

    NARCIS (Netherlands)

    Romanowsky, AJ; Douglas, NG; Kuijken, K; Arnaboldi, M; Gerssen, J; Merrifield, MR; Kwok, S; Dopita, M; Sutherland, R

    2003-01-01

    We have observed planetary nebulae (PNe) in several early-type galaxies using new techniques on 4- to 8-meter-class telescopes. We obtain the first large data sets (greater than or similar to 100 velocities each) of PN kinematics in galaxies at greater than or similar to 15 Mpc, and present some

  8. Protostar Evolution in the Orion Nebula Cluster (ONC)

    Science.gov (United States)

    Sanchez, Michael Allan

    2018-01-01

    We present our preliminary analysis of the protostars within the Orion Nebula Cluster (ONC). We developed a pipeline to identify protostars in the ONC using the IRAC instrument aboard Spitzer. We verified our photometric measurements with the catalog provided by Megeath et al. (2012). We then classified the protostar evolution stages (0/I, Flatt, II, and III) based on their spectral slope.

  9. Probing AGB nucleosynthesis via accurate Planetary Nebula abundances

    NARCIS (Netherlands)

    Marigo, P; Bernard-Salas, J; Pottasch, S. R.; Tielens, A. G. G. M.; Wesselius, P. R.

    2003-01-01

    The elemental abundances of ten planetary nebulae, derived with high accuracy including ISO and IUE spectra, are analysed with the aid of synthetic evolutionary models for the TP-AGB phase. The accuracy on the observed abundances is essential in order to make a reliable comparison with the models.

  10. Formation of planetary nebulae with close binary nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Livio, M; Salzman, J; Shaviv, G [Tel Aviv Univ. (Israel). Dept. of Physics and Astronomy

    1979-07-01

    A model for the formation of planetary nebulae with a close binary as a nucleus is presented. The model is based on mass loss instability at L/sub 2/. The instability is demonstrated. The conditions on the mass loss are formulated and analysed. The observational consequence of the model is described briefly and its relation to symbiotic stars and cataclysmic binaries discussed.

  11. Modelling the ArH+ emission from the Crab nebula

    Science.gov (United States)

    Priestley, F. D.; Barlow, M. J.; Viti, S.

    2017-12-01

    We have performed combined photoionization and photodissociation region (PDR) modelling of a Crab nebula filament subjected to the synchrotron radiation from the central pulsar wind nebula, and to a high flux of charged particles; a greatly enhanced cosmic-ray ionization rate over the standard interstellar value, ζ0, is required to account for the lack of detected [C I] emission in published Herschel SPIRE FTS observations of the Crab nebula. The observed line surface brightness ratios of the OH+ and ArH+ transitions seen in the SPIRE FTS frequency range can only be explained with both a high cosmic-ray ionization rate and a reduced ArH+ dissociative recombination rate compared to that used by previous authors, although consistent with experimental upper limits. We find that the ArH+/OH+ line strengths and the observed H2 vibration-rotation emission can be reproduced by model filaments with nH = 2 × 104 cm-3, ζ = 107ζ0 and visual extinctions within the range found for dusty globules in the Crab nebula, although far-infrared emission from [O I] and [C II] is higher than the observational constraints. Models with nH = 1900 cm-3 underpredict the H2 surface brightness, but agree with the ArH+ and OH+ surface brightnesses and predict [O I] and [C II] line ratios consistent with observations. These models predict HeH+ rotational emission above detection thresholds, but consideration of the formation time-scale suggests that the abundance of this molecule in the Crab nebula should be lower than the equilibrium values obtained in our analysis.

  12. Studies of dust grain properties in infrared reflection nebulae.

    Science.gov (United States)

    Pendleton, Y J; Tielens, A G; Werner, M W

    1990-01-20

    We have developed a model for reflection nebulae around luminous infrared sources embedded in dense dust clouds. The aim of this study is to determine the sizes of the scattering grains. In our analysis, we have adopted an MRN-like power-law size distribution (Mathis, Rumpl, and Nordsieck) of graphite and silicate grains, but other current dust models would give results which were substantially the same. In the optically thin limit, the intensity of the scattered light is proportional to the dust column density, while in the optically thick limit, it reflects the grain albedo. The results show that the shape of the infrared spectrum is the result of a combination of the scattering properties of the dust, the spectrum of the illuminating source, and foreground extinction, while geometry plays a minor role. Comparison of our model results with infrared observations of the reflection nebula surrounding OMC-2/IRS 1 shows that either a grain size distribution like that found in the diffuse interstellar medium, or one consisting of larger grains, can explain the observed shape of the spectrum. However, the absolute intensity level of the scattered light, as well as the observed polarization, requires large grains (approximately 5000 angstroms). By adding water ice mantles to the silicate and graphite cores, we have modeled the 3.08 micrometers ice band feature, which has been observed in the spectra of several infrared reflection nebulae. We show that this ice band arises naturally in optically thick reflection nebulae containing ice-coated grains. We show that the shape of the ice band is diagnostic of the presence of large grains, as previously suggested by Knacke and McCorkle. Comparison with observations of the BN/KL reflection nebula in the OMC-1 cloud shows that large ice grains (approximately 5000 angstroms) contribute substantially to the scattered light.

  13. Super-Acceleration in the Flaring Crab Nebula

    Energy Technology Data Exchange (ETDEWEB)

    Tavani, Marco, E-mail: marco.tavani@inaf.it

    2013-10-15

    The Crab Nebula continues to surprise us. The Crab system (energized by a very powerful pulsar at the center of the Supernova Remnant SN1054) is known to be a very efficient particle “accelerator” which can reach PeV energies. Today, new surprising data concerning the gamma-ray flares produced by the Crab Nebula challenge models of particle acceleration. The total energy flux from the Crab has been considered for many decades substantially stable at X-ray and gamma-ray energies. However, this paradigm was shattered by the AGILE discovery and Fermi confirmation in September 2010 of transient gamma-ray emission from the Crab. Indeed, we can state that four major flaring gamma-ray episodes have been detected by AGILE and Fermi during the period mid-2007/2012. During these events, transient particle acceleration occurs in a regime which apparently violates the MHD conditions and synchrotron cooling constraints. This fact justifies calling “super-acceleration” the mechanism which produces the “flaring Crab phenomenon”. Radiation between 50 MeV and a few GeV is emitted with a quite hard spectrum within a short timescale (hours-days), with no obvious relation with simultaneous optical and X-ray emissions in the inner Nebula. “Super-acceleration” implies overcoming synchrotron cooling by strong (and “parallel”) electric fields most likely produced by magnetic field reconnection within the pulsar wind outflow. This acceleration appears to be very efficient and, remarkably, limited by radiation reaction. It is not clear at the moment where in the Nebula this phenomenon occurs. An intense observational program is now focused on the Crab Nebula to resolve its most challenging mystery.

  14. Bipolar mixed features - Results from the comparative effectiveness for bipolar disorder (Bipolar CHOICE) study.

    Science.gov (United States)

    Tohen, Mauricio; Gold, Alexandra K; Sylvia, Louisa G; Montana, Rebecca E; McElroy, Susan L; Thase, Michael E; Rabideau, Dustin J; Nierenberg, Andrew A; Reilly-Harrington, Noreen A; Friedman, Edward S; Shelton, Richard C; Bowden, Charles L; Singh, Vivek; Deckersbach, Thilo; Ketter, Terence A; Calabrese, Joseph R; Bobo, William V; McInnis, Melvin G

    2017-08-01

    DSM-5 changed the criteria from DSM-IV for mixed features in mood disorder episodes to include non-overlapping symptoms of depression and hypomania/mania. It is unknown if, by changing these criteria, the same group would qualify for mixed features. We assessed how those meeting DSM-5 criteria for mixed features compare to those meeting DSM-IV criteria. We analyzed data from 482 adult bipolar patients in Bipolar CHOICE, a randomized comparative effectiveness trial. Bipolar diagnoses were confirmed through the MINI International Neuropsychiatric Interview (MINI). Presence and severity of mood symptoms were collected with the Bipolar Inventory of Symptoms Scale (BISS) and linked to DSM-5 and DSM-IV mixed features criteria. Baseline demographics and clinical variables were compared between mood episode groups using ANOVA for continuous variables and chi-square tests for categorical variables. At baseline, the frequency of DSM-IV mixed episodes diagnoses obtained with the MINI was 17% and with the BISS was 20%. Using DSM-5 criteria, 9% of participants met criteria for hypomania/mania with mixed features and 12% met criteria for a depressive episode with mixed features. Symptom severity was also associated with increased mixed features with a high rate of mixed features in patients with mania/hypomania (63.8%) relative to those with depression (8.0%). Data on mixed features were collected at baseline only and thus do not reflect potential patterns in mixed features within this sample across the study duration. The DSM-5 narrower, non-overlapping definition of mixed episodes resulted in fewer patients who met mixed criteria compared to DSM-IV. Copyright © 2017. Published by Elsevier B.V.

  15. The Chandra planetary nebula survey (CHANPLANS). II. X-ray emission from compact planetary nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, M.; Kastner, J. H. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Montez, R. Jr. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA (United States); Frew, D. J.; De Marco, O.; Parker, Q. A. [Department of Physics and Astronomy and Macquarie Research Centre for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, NSW 2109 (Australia); Jones, D. [Departamento de Física, Universidad de Atacama, Copayapu 485, Copiapó (Chile); Miszalski, B. [South African Astronomical Observatory, P.O. Box 9, Observatory, 7935 (South Africa); Sahai, R. [Jet Propulsion Laboratory, MS 183-900, California Institute of Technology, Pasadena, CA 91109 (United States); Blackman, E.; Frank, A. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Chu, Y.-H. [Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL (United States); Guerrero, M. A. [Instituto de Astrofísica de Andalucía, IAA-CSIC, Glorieta de la Astronomía s/n, Granada, E-18008 (Spain); Lopez, J. A. [Instituto de Astronomía, Universidad Nacional Autonoma de Mexico, Campus Ensenada, Apdo. Postal 22860, Ensenada, B. C. (Mexico); Zijlstra, A. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Bujarrabal, V. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Corradi, R. L. M. [Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain); Nordhaus, J. [NSF Astronomy and Astrophysics Fellow, Center for Computational Relativity and Gravitation, Rochester Institute of Technology, Rochester, NY 14623 (United States); and others

    2014-10-20

    We present results from the most recent set of observations obtained as part of the Chandra X-ray observatory Planetary Nebula Survey (CHANPLANS), the first comprehensive X-ray survey of planetary nebulae (PNe) in the solar neighborhood (i.e., within ∼1.5 kpc of the Sun). The survey is designed to place constraints on the frequency of appearance and range of X-ray spectral characteristics of X-ray-emitting PN central stars and the evolutionary timescales of wind-shock-heated bubbles within PNe. CHANPLANS began with a combined Cycle 12 and archive Chandra survey of 35 PNe. CHANPLANS continued via a Chandra Cycle 14 Large Program which targeted all (24) remaining known compact (R {sub neb} ≲ 0.4 pc), young PNe that lie within ∼1.5 kpc. Results from these Cycle 14 observations include first-time X-ray detections of hot bubbles within NGC 1501, 3918, 6153, and 6369, and point sources in HbDs 1, NGC 6337, and Sp 1. The addition of the Cycle 14 results brings the overall CHANPLANS diffuse X-ray detection rate to ∼27% and the point source detection rate to ∼36%. It has become clearer that diffuse X-ray emission is associated with young (≲ 5 × 10{sup 3} yr), and likewise compact (R {sub neb} ≲ 0.15 pc), PNe with closed structures and high central electron densities (n{sub e} ≳ 1000 cm{sup –3}), and is rarely associated with PNe that show H{sub 2} emission and/or pronounced butterfly structures. Hb 5 is one such exception of a PN with a butterfly structure that hosts diffuse X-ray emission. Additionally, two of the five new diffuse X-ray detections (NGC 1501 and NGC 6369) host [WR]-type central stars, supporting the hypothesis that PNe with central stars of [WR]-type are likely to display diffuse X-ray emission.

  16. Transient Stuttering in Catatonic Bipolar Patients

    Directory of Open Access Journals (Sweden)

    Anthony B. Joseph

    1991-01-01

    Full Text Available Two cases of transient stuttering occurring in association with catatonia and bipolar disorder are described. Affective decompensation has been associated with lateralized cerebral dysfunction, and it is hypothesized that in some bipolar catatonic patients a concomitant disorder of the lateralization of language function may lead to a variety of clinical presentations including aphasia, mutism, and stuttering.

  17. Swimming in Deep Water: Childhood Bipolar Disorder

    Science.gov (United States)

    Senokossoff, Gwyn W.; Stoddard, Kim

    2009-01-01

    The authors focused on one parent's struggles in finding a diagnosis and intervention for a child who had bipolar disorder. The authors explain the process of identification, diagnosis, and intervention of a child who had bipolar disorder. In addition to the personal story, the authors provide information on the disorder and outline strategies…

  18. Bipolar disorder diagnosis: challenges and future directions

    Science.gov (United States)

    Phillips, Mary L; Kupfer, David J

    2018-01-01

    Bipolar disorder refers to a group of affective disorders, which together are characterised by depressive and manic or hypomanic episodes. These disorders include: bipolar disorder type I (depressive and manic episodes: this disorder can be diagnosed on the basis of one manic episode); bipolar disorder type II (depressive and hypomanic episodes); cyclothymic disorder (hypomanic and depressive symptoms that do not meet criteria for depressive episodes); and bipolar disorder not otherwise specified (depressive and hypomanic-like symptoms that do not meet the diagnostic criteria for any of the aforementioned disorders). Bipolar disorder type II is especially difficult to diagnose accurately because of the difficulty in differentiation of this disorder from recurrent unipolar depression (recurrent depressive episodes) in depressed patients. The identification of objective biomarkers that represent pathophysiologic processes that differ between bipolar disorder and unipolar depression can both inform bipolar disorder diagnosis and provide biological targets for the development of new and personalised treatments. Neuroimaging studies could help the identification of biomarkers that differentiate bipolar disorder from unipolar depression, but the problem in detection of a clear boundary between these disorders suggests that they might be better represented as a continuum of affective disorders. Innovative combinations of neuroimaging and pattern recognition approaches can identify individual patterns of neural structure and function that accurately ascertain where a patient might lie on a behavioural scale. Ultimately, an integrative approach, with several biological measurements using different scales, could yield patterns of biomarkers (biosignatures) to help identify biological targets for personalised and new treatments for all affective disorders. PMID:23663952

  19. Bipolar Disorder and Cognitive Therapy: A Commentary

    Science.gov (United States)

    Riskind, John H.

    2005-01-01

    This article comments on the three articles (Leahy, 2005; Newman, 2005; and Reilly-Harrington & Knauz, 2005) that deal with the applications of cognitive therapy to treatment of bipolar disorder. They focus on the uses of cognitive therapy in treating three important facets of the special problems of bipolar patients: rapid cycling, severe…

  20. Perceived parental rearing of bipolar offspring

    NARCIS (Netherlands)

    Reichart, C. G.; van der Ende, J.; Hillegers, M. H. J.; Wals, M.; Bongers, I. L.; Nolen, W. A.; Ormel, J.; Verhulst, F. C.

    Objective: To explore the impact of growing up with a parent with a bipolar disorder. First, we compared parental rearing behavior perceived by young adult offspring of bipolar parents with parental rearing behavior perceived by same aged young adults from the general population. Secondly, we

  1. Cognitive behavioral therapy for bipolar disorders

    OpenAIRE

    Lotufo Neto, Francisco

    2004-01-01

    Descrição dos objetivos e principais técnicas da terapia comportamental cognitiva usadas para a psicoterapia das pessoas com transtorno bipolar.Objectives and main techniques of cognitive behavior therapy for the treatment of bipolar disorder patients are described.

  2. 2017 Bipolar Plate Workshop Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Kopasz, John P. [Argonne National Lab. (ANL), Argonne, IL (United States); Benjamin, Thomas G. [Argonne National Lab. (ANL), Argonne, IL (United States); Schenck, Deanna [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-08-17

    The Bipolar Plate (BP) Workshop was held at USCAR1 in Southfield, Michigan on February 14, 2017 and included 63 participants from industry, government agencies, universities, and national laboratories with expertise in the relevant fields. The objective of the workshop was to identify research and development (R&D) needs, in particular early-stage R&D, for bipolar plates for polymer electrolyte membrane (PEM) fuel cells for transportation applications. The focus of the workshop was on materials, manufacturing, and design aspects of bipolar plates with the goal of meeting DOE’s 2020 bipolar plate targets. Of special interest was the cost target of ≤$3/kW for the bipolar plate.

  3. PLANETARY NEBULAE IN FACE-ON SPIRAL GALAXIES. II. PLANETARY NEBULA SPECTROSCOPY

    International Nuclear Information System (INIS)

    Herrmann, Kimberly A.; Ciardullo, Robin

    2009-01-01

    As the second step in our investigation of the mass-to-light ratio of spiral disks, we present the results of a spectroscopic survey of planetary nebulae (PNe) in five nearby, low-inclination galaxies: IC 342, M74 (NGC 628), M83 (NGC 5236), M94 (NGC 4736), and M101 (NGC 5457). Using 50 setups of the WIYN/Hydra and Blanco/Hydra spectrographs, and 25 observations with the Hobby-Eberly Telescope's Medium Resolution Spectrograph, we determine the radial velocities of 99, 102, 162, 127, and 48 PNe, respectively, to a precision better than 15 km s -1 . Although the main purpose of this data set is to facilitate dynamical mass measurements throughout the inner and outer disks of large spiral galaxies, our spectroscopy has other uses as well. Here, we co-add these spectra to show that, to first order, the [O III] and Balmer line ratios of PNe vary little over the top ∼1.5 mag of the PN luminosity function. The only obvious spectral change occurs with [N II], which increases in strength as one proceeds down the luminosity function. We also show that typical [O III]-bright planetaries have E(B - V) ∼ 0.2 of circumstellar extinction, and that this value is virtually independent of [O III] luminosity. We discuss the implications this has for understanding the population of PN progenitors.

  4. The Making of a Pre-Planetary Nebula

    Science.gov (United States)

    Kohler, Susanna

    2017-07-01

    The gas expelled by dying stars gets twisted into intricate shapes and patterns as nebulae form. Now a team of researchers might have some answers about how this happens.Whats a Pre-Planetary Nebula?This H-R diagram for the globular cluster M5 shows where AGB stars lie: they are represented by blue markers here. The AGB is one of the final stages in a low- to intermediate-mass stars lifetime. [Lithopsian]When a low- to intermediate-mass star approaches the end of its lifetime, it moves onto the Asymptotic Giant Branch (AGB) in the Herzsprung-Russell diagram. As the star exhausts its fuel here, it shrugs off its outer layers. These layers of gas then encase the stars core, which is not yet hot enough to ionize the gas and cause it to glow.Instead, during this time the gas is relatively cool and dark, faintly reflecting light from the star and emitting only very dim infrared emission of its own. At this stage, the gas represents a pre-planetary nebula. Only later when the stellar core contracts enough to heat up and emit ionizing radiation does the nebula begin to properly glow, at which point it qualifies as a full planetary nebula.Images of OH231 in optical light (top) and 12CO (bottom) taken from the literature. [See Balick et al. 2017 for full credit]Unexpected ShapesPre-planetary nebulae are a very short-lived evolutionary stage, so weve observed only a few hundred of them which has left many unanswered questions about these objects.One particular mystery is that of their shapes: if these nebulae are formed by stars expelling their outer layers, we would naively expect them to be simple spherical shells and yet we observe pre-planetary nebulae to have intricate shapes and patterns. How does the star create these asymmetric shapes? A team of scientists led by Bruce Balick (University of Washington, Seattle) has now used simulations to address this question.Injecting MassBalick and collaborators use 3D hydrodynamic simulations to model one particular pre

  5. DeepBipolar: Identifying genomic mutations for bipolar disorder via deep learning.

    Science.gov (United States)

    Laksshman, Sundaram; Bhat, Rajendra Rana; Viswanath, Vivek; Li, Xiaolin

    2017-09-01

    Bipolar disorder, also known as manic depression, is a brain disorder that affects the brain structure of a patient. It results in extreme mood swings, severe states of depression, and overexcitement simultaneously. It is estimated that roughly 3% of the population of the United States (about 5.3 million adults) suffers from bipolar disorder. Recent research efforts like the Twin studies have demonstrated a high heritability factor for the disorder, making genomics a viable alternative for detecting and treating bipolar disorder, in addition to the conventional lengthy and costly postsymptom clinical diagnosis. Motivated by this study, leveraging several emerging deep learning algorithms, we design an end-to-end deep learning architecture (called DeepBipolar) to predict bipolar disorder based on limited genomic data. DeepBipolar adopts the Deep Convolutional Neural Network (DCNN) architecture that automatically extracts features from genotype information to predict the bipolar phenotype. We participated in the Critical Assessment of Genome Interpretation (CAGI) bipolar disorder challenge and DeepBipolar was considered the most successful by the independent assessor. In this work, we thoroughly evaluate the performance of DeepBipolar and analyze the type of signals we believe could have affected the classifier in distinguishing the case samples from the control set. © 2017 Wiley Periodicals, Inc.

  6. A YinYang bipolar fuzzy cognitive TOPSIS method to bipolar disorder diagnosis.

    Science.gov (United States)

    Han, Ying; Lu, Zhenyu; Du, Zhenguang; Luo, Qi; Chen, Sheng

    2018-05-01

    Bipolar disorder is often mis-diagnosed as unipolar depression in the clinical diagnosis. The main reason is that, different from other diseases, bipolarity is the norm rather than exception in bipolar disorder diagnosis. YinYang bipolar fuzzy set captures bipolarity and has been successfully used to construct a unified inference mathematical modeling method to bipolar disorder clinical diagnosis. Nevertheless, symptoms and their interrelationships are not considered in the existing method, circumventing its ability to describe complexity of bipolar disorder. Thus, in this paper, a YinYang bipolar fuzzy multi-criteria group decision making method to bipolar disorder clinical diagnosis is developed. Comparing with the existing method, the new one is more comprehensive. The merits of the new method are listed as follows: First of all, multi-criteria group decision making method is introduced into bipolar disorder diagnosis for considering different symptoms and multiple doctors' opinions. Secondly, the discreet diagnosis principle is adopted by the revised TOPSIS method. Last but not the least, YinYang bipolar fuzzy cognitive map is provided for the understanding of interrelations among symptoms. The illustrated case demonstrates the feasibility, validity, and necessity of the theoretical results obtained. Moreover, the comparison analysis demonstrates that the diagnosis result is more accurate, when interrelations about symptoms are considered in the proposed method. In a conclusion, the main contribution of this paper is to provide a comprehensive mathematical approach to improve the accuracy of bipolar disorder clinical diagnosis, in which both bipolarity and complexity are considered. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Gamma-ray flares from the Crab Nebula.

    Science.gov (United States)

    Abdo, A A; Ackermann, M; Ajello, M; Allafort, A; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bouvier, A; Brandt, T J; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Cannon, A; Caraveo, P A; Casandjian, J M; Çelik, Ö; Charles, E; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Costamante, L; Cutini, S; D'Ammando, F; Dermer, C D; de Angelis, A; de Luca, A; de Palma, F; Digel, S W; do Couto e Silva, E; Drell, P S; Drlica-Wagner, A; Dubois, R; Dumora, D; Favuzzi, C; Fegan, S J; Ferrara, E C; Focke, W B; Fortin, P; Frailis, M; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; Hayashi, K; Hayashida, M; Hays, E; Horan, D; Itoh, R; Jóhannesson, G; Johnson, A S; Johnson, T J; Khangulyan, D; Kamae, T; Katagiri, H; Kataoka, J; Kerr, M; Knödlseder, J; Kuss, M; Lande, J; Latronico, L; Lee, S-H; Lemoine-Goumard, M; Longo, F; Loparco, F; Lubrano, P; Madejski, G M; Makeev, A; Marelli, M; Mazziotta, M N; McEnery, J E; Michelson, P F; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Naumann-Godo, M; Nolan, P L; Norris, J P; Nuss, E; Ohsugi, T; Okumura, A; Omodei, N; Ormes, J F; Ozaki, M; Paneque, D; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Pierbattista, M; Piron, F; Porter, T A; Rainò, S; Rando, R; Ray, P S; Razzano, M; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Romani, R W; Sadrozinski, H F-W; Sanchez, D; Saz Parkinson, P M; Scargle, J D; Schalk, T L; Sgrò, C; Siskind, E J; Smith, P D; Spandre, G; Spinelli, P; Strickman, M S; Suson, D J; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, J B; Thompson, D J; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Troja, E; Uchiyama, Y; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Wang, P; Wood, K S; Yang, Z; Ziegler, M

    2011-02-11

    A young and energetic pulsar powers the well-known Crab Nebula. Here, we describe two separate gamma-ray (photon energy greater than 100 mega-electron volts) flares from this source detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The first flare occurred in February 2009 and lasted approximately 16 days. The second flare was detected in September 2010 and lasted approximately 4 days. During these outbursts, the gamma-ray flux from the nebula increased by factors of four and six, respectively. The brevity of the flares implies that the gamma rays were emitted via synchrotron radiation from peta-electron-volt (10(15) electron volts) electrons in a region smaller than 1.4 × 10(-2) parsecs. These are the highest-energy particles that can be associated with a discrete astronomical source, and they pose challenges to particle acceleration theory.

  8. Million-degree plasma pervading the extended Orion Nebula.

    Science.gov (United States)

    Güdel, Manuel; Briggs, Kevin R; Montmerle, Thierry; Audard, Marc; Rebull, Luisa; Skinner, Stephen L

    2008-01-18

    Most stars form as members of large associations within dense, very cold (10 to 100 kelvin) molecular clouds. The nearby giant molecular cloud in Orion hosts several thousand stars of ages less than a few million years, many of which are located in or around the famous Orion Nebula, a prominent gas structure illuminated and ionized by a small group of massive stars (the Trapezium). We present x-ray observations obtained with the X-ray Multi-Mirror satellite XMM-Newton, revealing that a hot plasma with a temperature of 1.7 to 2.1 million kelvin pervades the southwest extension of the nebula. The plasma flows into the adjacent interstellar medium. This x-ray outflow phenomenon must be widespread throughout our Galaxy.

  9. Spectrophotometry of Bowen resonance fluorescence lines in three planetary nebulae

    Science.gov (United States)

    O'Dell, C. R.; Miller, Christopher O.

    1992-01-01

    The results are presented of a uniquely complete, carefully reduced set of observations of the O III Bowen fluorescence lines in the planetary nebulae NGC 6210, NGC 7027, and NGC 7662. A detailed comparison with the predictions of radiative excitation verify that some secondary lines are enhanced by selective population by the charge exchange mechanism involving O IV. Charge exchange is most important in NGC 6210, which is of significantly lower ionization than the other nebulae. In addition to the principal Bowen lines arising from Ly-alpha pumping of the O III O1 line, lines arising from pumping of the O3 line are also observed. Comparison of lines produced by O1 and O3 with the theoretical predictions of Neufeld indicate poor agreement; comparison with the theoretical predictions of Harrington show agreement with NGC 7027 and NGC 7662.

  10. Catalysis by Dust Grains in the Solar Nebula

    Science.gov (United States)

    Kress, Monika E.; Tielens, Alexander G. G. M.

    1996-01-01

    In order to determine whether grain-catalyzed reactions played an important role in the chemistry of the solar nebula, we have applied our time-dependent model of methane formation via Fischer-Tropsch catalysis to pressures from 10(exp -5) to 1 bar and temperatures from 450 to 650 K. Under these physical conditions, the reaction 3H2 + CO yields CH4 + H2O is readily catalyzed by an iron or nickel surface, whereas the same reaction is kinetically inhibited in the gas phase. Our model results indicate that under certain nebular conditions, conversion of CO to methane could be extremely efficient in the presence of iron-nickel dust grains over timescales very short compared to the lifetime of the solar nebula.

  11. The gas-to-dust ratio in the Orion nebula

    International Nuclear Information System (INIS)

    Perinotto, M.; Patriarchi, P.

    1974-01-01

    About sixty spectra have been obtained using an image tube with the nebular spectrograph of the Asiago 122cm reflector, in a position W-E from north of the Trapezium across the star P 1925 into the bay area of the Orion Nebula. Twenty-five spectra have been selected for accurate measurements of the Hβ intensity and of the electron density by the [S II] 6730/6716 intensity line ratio. The results are interpreted in terms of well-mixed gas and dust, not only in the central bright regions, but even in the bay area, where the coefficient of dust extinction counted per electron is found to be larger than in the bright centre of the nebula

  12. Gamma-ray flares from the Crab nebula

    International Nuclear Information System (INIS)

    Abdo, A.A.; Ackermann, M.; Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Casandjian, J.M.; Grenier, I.A.; Naumann-Godo, M.; Pierbattista, M.; Tibaldo, L.

    2011-01-01

    A young and energetic pulsar powers the well-known Crab Nebula. Here, we describe two separate gamma-ray (photon energy greater than 100 mega-electron volts) flares from this source detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The first flare occurred in February 2009 and lasted approximately 16 days. The second flare was detected in September 2010 and lasted approximately 4 days. During these outbursts, the gamma-ray flux from the nebula increased by factors of four and six, respectively. The brevity of the flares implies that the gamma rays were emitted via synchrotron radiation from peta-electron-volt (10 15 electron volts) electrons in a region smaller than 1.4 * 10 -2 parsecs. These are the highest-energy particles that can be associated with a discrete astronomical source, and they pose challenges to particle acceleration theory. (authors)

  13. Probing Shocks of the Young Planetary Nebula NGC 7027

    Science.gov (United States)

    Montez, Rodolfo

    2013-09-01

    The rapid evolution of the planetary nebula NGC 7027 provides a rare glimpse at the evolution of the shocks. We propose a detailed spatial and spectroscopic study of the shock conditions in NGC 7027 that will enhance and bridge our understanding of the shocks seen in other planetary nebula. Comparison between the Cycle 1 observation and a new Cycle 15 observation will (i) confirm the presence of the two components in the extended X-ray emission, (ii) measure the changes (spatial and spectral) in the components, and, (iii) provide a valuable trove of tests and inputs for shock conditions and hydrodynamical simulations. We rely on the unprecedented spatial resolution and soft-sensitivity of Chandra.

  14. Identification of faint central stars in extended, low-surface-brightness planetary nebulae

    International Nuclear Information System (INIS)

    Kwitter, K.B.; Lydon, T.J.; Jacoby, G.H.

    1988-01-01

    As part of a larger program to study the properties of planetary nebula central stars, a search for faint central stars in extended, low-surface-brightness planetary nebulae using CCD imaging is performed. Of 25 target nebulae, central star candidates have been identified in 17, with certainties ranging from extremely probable to possible. Observed V values in the central star candidates extend to fainter than 23 mag. The identifications are presented along with the resulting photometric measurements. 24 references

  15. Variation of the extinction law in the Trifid nebula

    OpenAIRE

    Cambrésy, L.; Rho, J.; Marshall, D. J.; Reach, W. T.

    2011-01-01

    Context. In the past few years, the extinction law has been measured in the infrared wavelengths for various molecular clouds and different laws have been obtained. Aims. In this paper we seek variations of the extinction law within the Trifid nebula region. Such variations would demonstrate local dust evolution linked to variation of the environment parameters such as the density or the interstellar radiation field. Methods. The extinction values, A_λ/A_v, are obtained using the 2MASS, UKIDS...

  16. Very bright optical transient near the Trifid and Lagoon Nebulae

    Science.gov (United States)

    Dunsby, Peter

    2018-03-01

    Peter Dunsby (University of Cape Town) reports the detection of a very bright optical transient in the region between the Lagoon and Trifid Nebulae based on observations obtained from Cape Town on 20 March 2018, between 01:00 and 03:45 UT. The object was visible throughout the full duration of the observations and not seen when this field was observed previously (08 March 2018).

  17. YOUNG STARLESS CORES EMBEDDED IN THE MAGNETICALLY DOMINATED PIPE NEBULA

    International Nuclear Information System (INIS)

    Frau, P.; Girart, J. M.; Alves, F. O.; Beltran, M. T.; Morata, O.; Masque, J. M.; Busquet, G.; Sanchez-Monge, A.; Estalella, R.; Franco, G. A. P.

    2010-01-01

    The Pipe Nebula is a massive, nearby dark molecular cloud with a low star formation efficiency which makes it a good laboratory in which to study the very early stages of the star formation process. The Pipe Nebula is largely filamentary and appears to be threaded by a uniform magnetic field at scales of a few parsecs, perpendicular to its main axis. The field is only locally perturbed in a few regions, such as the only active cluster-forming core B59. The aim of this study is to investigate primordial conditions in low-mass pre-stellar cores and how they relate to the local magnetic field in the cloud. We used the IRAM 30 m telescope to carry out a continuum and molecular survey at 3 and 1 mm of early- and late-time molecules toward four selected starless cores inside the Pipe Nebula. We found that the dust continuum emission maps trace the densest regions better than previous Two Micron All Sky Survey (2MASS) extinction maps, while 2MASS extinction maps trace the diffuse gas better. The properties of the cores derived from dust emission show average radii of ∼0.09 pc, densities of ∼1.3x10 5 cm -3 , and core masses of ∼2.5 M sun . Our results confirm that the Pipe Nebula starless cores studied are in a very early evolutionary stage and present a very young chemistry with different properties that allow us to propose an evolutionary sequence. All of the cores present early-time molecular emission with CS detections in the whole sample. Two of them, cores 40 and 109, present strong late-time molecular emission. There seems to be a correlation between the chemical evolutionary stage of the cores and the local magnetic properties that suggests that the evolution of the cores is ruled by a local competition between the magnetic energy and other mechanisms, such as turbulence.

  18. THE LINE POLARIZATION WITHIN A GIANT Lyα NEBULA

    International Nuclear Information System (INIS)

    Prescott, Moire K. M.; Smith, Paul S.; Schmidt, Gary D.; Dey, Arjun

    2011-01-01

    Recent theoretical work has suggested that Lyα nebulae could be substantially polarized in the Lyα emission line, depending on the geometry, kinematics, and powering mechanism at work. Polarization observations can therefore provide a useful constraint on the source of ionization in these systems. In this Letter, we present the first Lyα polarization measurements for a giant Lyα nebula at z∼ 2.656. We do not detect any significant linear polarization of the Lyα emission: P Lyα = 2.6% ± 2.8% (corrected for statistical bias) within a single large aperture. The current data also do not show evidence for the radial polarization gradient predicted by some theoretical models. These results rule out singly scattered Lyα (e.g., from the nearby active galactic nucleus, AGN) and may be inconsistent with some models of backscattering in a spherical outflow. However, the effects of seeing, diminished signal-to-noise ratio, and angle averaging within radial bins make it difficult to put strong constraints on the radial polarization profile. The current constraints may be consistent with higher density outflow models, spherically symmetric infall models, photoionization by star formation within the nebula or the nearby AGN, resonant scattering, or non-spherically symmetric cold accretion (i.e., along filaments). Higher signal-to-noise ratio data probing to higher spatial resolution will allow us to harness the full diagnostic power of polarization observations in distinguishing between theoretical models of giant Lyα nebulae.

  19. Helix Nebula Science Cloud pilot phase open session

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    This Helix Nebula Science Cloud (HNSciCloud) public session is open to everyone and will be webcast. The session will provide the audience with an overview of the HNSciCloud pre-commercial procurement project and the innovative cloud platforms that have been developed. A number of practical use-cases from the physics community will be presented as well as the next steps to be undertaken.

  20. Lower switch rate in depressed patients with bipolar II than bipolar I disorder treated adjunctively with second-generation antidepressants

    NARCIS (Netherlands)

    Altshuler, LL; Suppes, T; Nolen, WA; Leverich, G; Keck, PE; Frye, MA; Kupka, R; McElroy, SL; Grunze, H; Kitchen, CMR; Post, R; Black, D.O.

    Objectives: The authors compared the switch rate into hypomania/mania in depressed patients treated with second-generation antidepressants who had either bipolar I or bipolar II disorder. Method: In a 10-week trial, 184 outpatients with bipolar depression (134 with bipolar I disorder, 48 with

  1. Brief Report: A Family Risk Study Exploring Bipolar Spectrum Problems and Cognitive Biases in Adolescent Children of Bipolar Parents

    Science.gov (United States)

    Espie, Jonathan; Jones, Steven H.; Vance, Yvonne H.; Tai, Sara J.

    2012-01-01

    Children of parents with bipolar disorder are at increased risk of bipolar spectrum diagnoses. This cross-sectional study explores cognitive factors in the prediction of vulnerability to bipolar disorder. Adolescents at high-risk (with a parent with bipolar disorder; n = 23) and age and gender matched adolescents (n = 24) were recruited. Parent…

  2. Isotopic homogeneity of iron in the early solar nebula.

    Science.gov (United States)

    Zhu, X K; Guo, Y; O'Nions, R K; Young, E D; Ash, R D

    2001-07-19

    The chemical and isotopic homogeneity of the early solar nebula, and the processes producing fractionation during its evolution, are central issues of cosmochemistry. Studies of the relative abundance variations of three or more isotopes of an element can in principle determine if the initial reservoir of material was a homogeneous mixture or if it contained several distinct sources of precursor material. For example, widespread anomalies observed in the oxygen isotopes of meteorites have been interpreted as resulting from the mixing of a solid phase that was enriched in 16O with a gas phase in which 16O was depleted, or as an isotopic 'memory' of Galactic evolution. In either case, these anomalies are regarded as strong evidence that the early solar nebula was not initially homogeneous. Here we present measurements of the relative abundances of three iron isotopes in meteoritic and terrestrial samples. We show that significant variations of iron isotopes exist in both terrestrial and extraterrestrial materials. But when plotted in a three-isotope diagram, all of the data for these Solar System materials fall on a single mass-fractionation line, showing that homogenization of iron isotopes occurred in the solar nebula before both planetesimal accretion and chondrule formation.

  3. Modeling radio circular polarization in the Crab nebula

    Science.gov (United States)

    Bucciantini, N.; Olmi, B.

    2018-03-01

    In this paper, we present, for the first time, simulated maps of the circularly polarized synchrotron emission from the Crab nebula, using multidimensional state of the art models for the magnetic field geometry. Synchrotron emission is the signature of non-thermal emitting particles, typical of many high-energy astrophysical sources, both Galactic and extragalactic ones. Its spectral and polarization properties allow us to infer key information on the particles distribution function and magnetic field geometry. In recent years, our understanding of pulsar wind nebulae has improved substantially thanks to a combination of observations and numerical models. A robust detection or non-detection of circular polarization will enable us to discriminate between an electron-proton plasma and a pair plasma, clarifying once for all the origin of the radio emitting particles, setting strong constraints on the pair production in pulsar magnetosphere, and the role of turbulence in the nebula. Previous attempts at measuring the circular polarization have only provided upper limits, but the lack of accurate estimates, based on reliable models, makes their interpretation ambiguous. We show here that those results are above the expected values, and that current polarimetric techniques are not robust enough for conclusive result, suggesting that improvements in construction and calibration of next generation radio facilities are necessary to achieve the desired sensitivity.

  4. The Formation of Graphite Whiskers in the Primitive Solar Nebula

    Science.gov (United States)

    Nuth, Joseph A., III; Kimura, Yuki; Lucas, Christopher; Ferguson, Frank; Johnson, Natasha M.

    2010-01-01

    It has been suggested that carbonaceous grains are efficiently destroyed in the interstellar medium and must either reform in situ at very low pressures and temperatures or in an alternative environment more conducive to grain growth. Graphite whiskers have been discovered associated with high-temperature phases in meteorites such as calcium aluminum inclusions and chondrules, and it has been suggested that the expulsion of such material from proto stellar nebulae could significantly affect the optical properties of the average interstellar grain population. We have experimentally studied the potential for Fischer-Tropsch and Haber-Bosch type reactions to produce organic materials in protostellar systems from the abundant H2, CO, and N2 reacting on the surfaces of available silicate grains. When graphite grains are repeatedly exposed to H2, CO, and N2 at 875 K abundant graphite whiskers are observed to form on or from the surfaces of the graphite grains. In a dense, turbulent nebula, such extended whiskers are very likely to be broken off, and fragments could be ejected either in polar jets or by photon pressure after transport to the outer reaches of the nebula.

  5. CO survey of the dark nebulae in Taurus and Perseus

    International Nuclear Information System (INIS)

    Baran, G.P.

    1986-01-01

    The thesis reports a large-scale survey of carbon monoxide ( 12 CO) emission (at λ = 2.6 mm) from dark nebulae in Taurus and Perseus. CO spectra at 4395 points were obtained within an area of about 800 square degrees generally west of the galactic anti-center. The spatial resolution of the instrument was eight arcminutes and velocity resolution was 2.6 km s -1 /. CO emission is strongest wherever extinction by dust is greatest, spilling over the apparent outer boundaries of the dust clouds observed optically. Combining CO velocity for the nebulae with optically determined distances shows that the clouds in the survey area form several layers. The molecular cloud mass closest to the sun is the Taurus and Auriga complex about 150 +/- 50 pc). Nearer to the Per )B2 OB association (at 350 +/- 100 pc) than the Taurus clouds are the Per OB2 molecular cloud (350 +/- 100 pc) and the California Nebula = NGC15979 molecular clouds (at 400 +/- 150 pc). Cloud masses were determined from integrated CO emission intensity alone by assuming that γ-ray emission intensities can be used to relate H 2 column densities to CO emission intensities

  6. He I lambda 584 in quasars and gaseous nebulae

    International Nuclear Information System (INIS)

    Ferland, G.J.

    1980-01-01

    The He I Lα lambda 584 transfer problem for gaseous nebulae is investigated. Realistic photo-ionization models of quasar clouds and planetary nebulae are combined with the Monte Carlo line transfer technique to determine both the efficiency of destruction of lambda 584 by photo-ionization of hydrogen and the mean number of scatterings undergone before destruction. It is found that large fractions (approximately > 90 per cent) of the lambda 584 photons are destroyed before escaping in all cases considered. Nonetheless, the He I lambda lambda 584, 626 doublet should be present in high redshift quasars with an observed equivalent width of approximately 1 A. Detection of this doublet would provide the only clear indication of the presence or absence of a low density narrow line region for objects in which optical forbidden lines have been redshifted beyond the optical window. The strength of the He I 2 1 S-2 1 P 2.0 μm line is predicted to be approximately 4 times stronger than is actually observed in the planetary nebulae NGC 7027. This suggests that dust is embedded in the ionized gas and causes additional destruction of lambda 584. Finally, the calculations show that photo-ionization model calculations can safely assume nearly complete on-the-spot destruction of lambda 584. The common assumption that the He I singlets are formed in case B conditions is examined in an appendix. (author)

  7. Collisional effects in He I lines and helium abundances in planetary nebulae

    International Nuclear Information System (INIS)

    Clegg, R.E.S.

    1987-01-01

    Attention is drawn to new, 19-state quantal calculations for collisional excitation by electron impact in neutral helium. Recommended empirical formulae are given for the collisional contribution to HeI recombination lines such as λλ4471, 5876 A in gaseous nebulae. Collisional ionization of metastable (2 3 S) He I is significant for high-temperature nebulae. Collisional transfers provide significant cooling in nebulae with low heavy-element abundances. Revised mean He/H ratios for three large samples of planetary nebulae are given. (author)

  8. The internal kinematics of the planetary nebula NGC 650/1

    International Nuclear Information System (INIS)

    Taylor, K.

    1979-01-01

    Hα and [N II], lambda 6584 line profiles from the bright lobes of planetary nebula NGC 650/1 have been obtained. These emission lines show a very strong symmetrical triple-peak velocity structure, not observed previously to the author's knowledge in planetary nebulae. Models are tentatively proposed to explain both the velocity data and the nebula's optical appearance. The velocity splitting amounts to approximately 62 km/s and the rest frame of the nebula is found to have a heliocentric radial velocity of -19 +- 2 km/s. (author)

  9. The nature of the nebula associated with the luminous blue variable star WRA 751

    OpenAIRE

    Hutsemekers, Damien; van Drom, E.

    1991-01-01

    Narrow-band filter imagery as well as medium to high resolution spectroscopy of the nebula surrounding the luminous blue variable (LBV) star WRA 751 are presented. The nebula appears as a slowly expanding H II region of low excitation characterized by a significant N/O overabundance which may be due to the presence in the nebula of nuclear processed material ejected by the star. With the recent discovery of a nebula around HR Car, all but one known galactic LBVs are now shown to be associated...

  10. VALPROATE, BIPOLAR DISORDER AND POLYCYSTIC OVARIAN SYNDROME.

    Science.gov (United States)

    Okanović, Milana; Zivanović, Olga

    2016-01-01

    Polycystic ovarian syndrome is a syndrome of ovarian dysfunction with the principal features of hyperandrogenism and polycystic ovary morphology. A large number of studies conducted on this topic have suggested a possible role of anticonvulsants, particularly valproate, in the pathogenesis or risk factors associated with polycystic ovarian syndrome. Bipolar treatment guidelines from Canada and the United States of America recommend valproate as the first line strategy in the acute treatment of bipolar disorder. Most persons with bipolar disorder require maintenance treatment. Long-term administration of valproate in women with bipolar disorder or epilepsy is believed to result in the increased risk of hyperandrogenism, menstrual abnormalities and polycystic ovaries. Valproate may also increase the risk of infertility and other associated symptoms of polycystic ovarian syndrome. Therefore, particular caution is indicated in the use of valproate in women of reproductive age. The treatment of the female patients with bipolar disorder presents various challenges for the clinician. Every woman of reproductive age needs to know the risk and benefits of her pharmacologic treatment options. Bipolar disorder should be considered chronic disorder, whose development is largely affected by hormonal changes and reproductive cycle in women. These issues should be researched more thoroughly in order to opt for the most appropriate treatment in women with bipolar disorder.

  11. Bipolar plates for PEM fuel cells

    Science.gov (United States)

    Middelman, E.; Kout, W.; Vogelaar, B.; Lenssen, J.; de Waal, E.

    The bipolar plates are in weight and volume the major part of the PEM fuel cell stack, and are also a significant contributor to the stack costs. The bipolar plate is therefore a key component if power density has to increase and costs must come down. Three cell plate technologies are expected to reach targeted cost price levels, all having specific advantages and drawbacks. NedStack has developed a conductive composite materials and a production process for fuel cell plates (bipolar and mono-polar). The material has a high electric and thermal conductivity, and can be processed into bipolar plates by a proprietary molding process. Process cycle time has been reduced to less than 10 s, making the material and process suitable for economical mass production. Other development work to increase material efficiency resulted in thin bipolar plates with integrated cooling channels, and integrated seals, and in two-component bipolar plates. Total thickness of the bipolar plates is now less than 3 mm, and will be reduced to 2 mm in the near future. With these thin integrated plates it is possible to increase power density up to 2 kW/l and 2 kW/kg, while at the same time reducing cost by integrating other functions and less material use.

  12. Distinctions of bipolar disorder symptoms in adolescence.

    Science.gov (United States)

    Gudiene, Devika; Leskauskas, Darius; Markeviciūte, Aurelija; Klimavicius, Dalius; Adomaitiene, Virginija

    2008-01-01

    Bipolar disorder in adolescents is a serious mental illness with problematic diagnosis that adversely affects social, academic, emotional, and family functioning. The objective of this study was to analyze features of premorbid and clinical symptoms, comorbidity, and course of bipolar disorder in adolescence. Data for analysis were collected from all case histories (N=6) of 14-18-year-old patients, hospitalized with diagnosis of bipolar disorder in the Unit of Children's and Adolescents' Psychiatry, Department of Psychiatry, Hospital of Kaunas University of Medicine, during the period from 2000 to 2005. Analysis of bipolar disorder course showed that five patients previously had been diagnosed with an episode of depression. The most frequent symptoms typical to bipolar disorder were disobedience and impulsive behavior, rapid changes of mood. The most common premorbid features were frequent changes of mood, being active in communication, hyperactive behavior. Adolescence-onset bipolar disorder was frequently comorbid with emotionally instable personality disorder, borderline type. Findings of the study confirm the notion that oppositional or impulsive behavior, rapid changes of mood without any reason, dysphoric mood and euphoric mood episodes with increased energy were cardinal symptoms of bipolar disorder with mania in adolescents. Most frequent premorbid features of these patients were quite similar to attention-deficit/hyperactivity disorder making differential diagnosis problematic.

  13. Evidence for Widespread 26Al in the Solar Nebula and Constraints for Nebula Time Scales

    Science.gov (United States)

    Russell; Srinivasan; Huss; Wasserburg; MacPherson

    1996-08-09

    A search was made for 26Mg (26Mg*) from the decay of 26Al (half-life = 0.73 million years) in Al-rich objects from unequilibrated ordinary chondrites. Two Ca-Al-rich inclusions (CAIs) and two Al-rich chondrules (not CAIs) were found that contained 26Al when they formed. Internal isochrons for the CAIs yielded an initial 26Al/27Al ratio [(26Al/27Al)0] of 5 x 10(-5), indistinguishable from most CAIs in carbonaceous chondrites. This result shows that CAIs with this level of 26Al are present throughout the classes of chondrites and strengthens the notion that 26Al was widespread in the early solar system. The two Al-rich chondrules have lower 26Mg*, corresponding to a (26Al/27Al)0 ratio of approximately 9 x 10(-6). Five other Al-rich chondrules contain no resolvable 26Mg*. If chondrules and CAIs formed from an isotopically homogeneous reservoir, then the chondrules with 26Al must have formed or been last altered approximately2 million years after CAIs formed; the 26Mg*-free chondrules formed >1 to 3 million years later still. Because 26Mg*-containing and 26Mg*-free chondrules are both found in Chainpur, which was not heated to more than approximately400°C, it follows that parent body metamorphism cannot explain the absence of 26Mg* in some of these chondrules. Rather, its absence indicates that the lifetime of the solar nebula over which CAIs and chondrules formed extended over approximately5 million years.

  14. Paired structures and bipolar knowledge representation

    DEFF Research Database (Denmark)

    Montero, Javier; Bustince, Humberto; Franco, Camilo

    In this strictly positional paper we propose a general approach to bipolar knowledge representation, where the meaning of concepts can be modelled by examining their decomposition into opposite and neutral categories. In particular, it is the semantic relationship between the opposite categories...... and at the same time the type of neutrality rising in between opposites. Based on this first level of bipolar knowledge representation, paired structures in fact offer the means to characterize a specific bipolar valuation scale depending on the meaning of the concept that has to be verified. In this sense...

  15. Bipolar Disorder and Early Affective Trauma.

    Science.gov (United States)

    de Codt, Aloise; Monhonval, Pauline; Bongaerts, Xavier; Belkacemi, Ikram; Tecco, Juan Martin

    2016-09-01

    Bipolar disorder is a chronic psychiatric disease with a high prevalence and is a major psychosocial and medical burden. The exact etiological pathways of bipolar disorder are not fully understood. Genetic factors are known to play an important role in the etiology of bipolar disorder. However, high rates of discordance among identical twins and a growing body of evidence that environmental factors such as early stress can influence the onset and course of psychiatric diseases underline the importance of additional etiological mechanisms of bipolar disorders. There has been little investigation about early trauma in bipolar disorder. The aim of this study was to review the literature on the association between early traumatic interactions like child neglect, mistreatment, abuse or early parental separation and the occurrence of bipolar disorder in adulthood or impact on the course of the disease. Studies investigating associations between child neglect, mistreatment, abuse or early parental separation and occurrence of bipolar disorder in adulthood or impact on the course of the disease were searched in the Pubmed database. More than 700 articles were sorted independently by two of the authors using predefined criteria. Only research articles, reviews and meta-analyses were selected for this review. 53 articles met the inclusion criteria. To date, four systematic reviews partially addressed our research question. Early trauma is more frequently found in the past of bipolar patients than in the general population. Studies support a harmful effect of childhood trauma on the course of bipolar disease, with more anxious, depressive or psychotic symptoms, an early age of onset and a worse prognosis. Early trauma is more often found in the past of bipolar adult patients than the general population and studies support a harmful effect of childhood trauma on the course of bipolar disease, with more anxious, depressive or psychotic symptoms, an early age of onset and a

  16. Ionizing radiations simulation on bipolar components

    International Nuclear Information System (INIS)

    Montagner, X.

    1999-01-01

    This thesis presents the ionizing radiation effects on bipolar components and more specially their behavior facing the total dose. The first part is devoted to the radiation environments with a special attention to the spatial environments and new emergent environments. The specificities of bipolar components are then presented and their behavior facing the interactions. The physical mechanisms bound to the dose rate are also discussed. The second part presents a physical analysis of degradations induced by the cumulated dosimetry on bipolar components and simulation with the ATLAS code. The third part exposes an electric empirical simulation induced by the cumulated dose in static conditions. (A.L.B.)

  17. The Charge State of Polycyclic Aromatic Hydrocarbons across a Reflection Nebula, an H II Region, and a Planetary Nebula

    Science.gov (United States)

    Boersma, C.; Bregman, J.; Allamandola, L. J.

    2018-05-01

    Low-resolution Spitzer-IRS spectral map data of a reflection nebula (NGC 7023), H II region (M17), and planetary nebula (NGC 40), totaling 1417 spectra, are analyzed using the data and tools available through the NASA Ames PAH IR Spectroscopic Database. The polycyclic aromatic hydrocarbon (PAH) emission is broken down into PAH charge and size subclass contributions using a database-fitting approach. The resulting charge breakdown results are combined with those derived using the traditional PAH band strength ratio approach, which interprets particular PAH band strength ratios as proxies for PAH charge. Here the 6.2/11.2 μm PAH band strength ratio is successfully calibrated against its database equivalent: the {n}PAH}+}/{n}PAH}0} ratio. In turn, this ratio is converted into the PAH ionization parameter, which relates it to the strength of the radiation field, gas temperature, and electron density. Population diagrams are used to derive the {{{H}}}2 density and temperature. The bifurcated plot of the 8.6 versus 11.2 μm PAH band strength for the northwest photo dissociation region in NGC 7023 is shown to be a robust diagnostic template for the {n}PAH}+}/{n}PAH}0} ratio in all three objects. Template spectra for the PAH charge and size subclasses are determined for each object and shown to favorably compare. Using the determined template spectra from NGC 7023 to fit the emission in all three objects yields, upon inspection of the Structure SIMilarity maps, satisfactory results. The choice of extinction curve proves to be critical. Concluding, the distinctly different astronomical environments of a reflection nebula, H II region, and planetary nebula are reflected in their PAH emission spectra.

  18. Progression along the Bipolar Spectrum: A Longitudinal Study of Predictors of Conversion from Bipolar Spectrum Conditions to Bipolar I and II Disorders

    Science.gov (United States)

    Alloy, Lauren B.; Urošević, Snežana; Abramson, Lyn Y.; Jager-Hyman, Shari; Nusslock, Robin; Whitehouse, Wayne G.; Hogan, Michael

    2011-01-01

    Little longitudinal research has examined progression to more severe bipolar disorders in individuals with “soft” bipolar spectrum conditions. We examine rates and predictors of progression to bipolar I and II diagnoses in a non-patient sample of college-age participants (n = 201) with high General Behavior Inventory scores and childhood or adolescent onset of “soft” bipolar spectrum disorders followed longitudinally for 4.5 years from the Longitudinal Investigation of Bipolar Spectrum (LIBS) project. Of 57 individuals with initial cyclothymia or bipolar disorder not otherwise specified (BiNOS) diagnoses, 42.1% progressed to a bipolar II diagnosis and 10.5% progressed to a bipolar I diagnosis. Of 144 individuals with initial bipolar II diagnoses, 17.4% progressed to a bipolar I diagnosis. Consistent with hypotheses derived from the clinical literature and the Behavioral Approach System (BAS) model of bipolar disorder, and controlling for relevant variables (length of follow-up, initial depressive and hypomanic symptoms, treatment-seeking, and family history), high BAS sensitivity (especially BAS Fun Seeking) predicted a greater likelihood of progression to bipolar II disorder, whereas early age of onset and high impulsivity predicted a greater likelihood of progression to bipolar I (high BAS sensitivity and Fun-Seeking also predicted progression to bipolar I when family history was not controlled). The interaction of high BAS and high Behavioral Inhibition System (BIS) sensitivities also predicted greater likelihood of progression to bipolar I. We discuss implications of the findings for the bipolar spectrum concept, the BAS model of bipolar disorder, and early intervention efforts. PMID:21668080

  19. The thermodynamics of bipolarity: a bifurcation model of bipolar illness and bipolar character and its psychotherapeutic applications.

    Science.gov (United States)

    Sabelli, H C; Carlson-Sabelli, L; Javaid, J I

    1990-11-01

    Two models dominate current formulations of bipolar illness: the homeostatic model implicit in Freud's psychodynamics and most neuroamine deficit/excess theories; and the oscillatory model of exaggerated biological rhythms. The homeostatic model is based on the closed systems approach of classic thermodynamics, while the oscillatory model requires the open systems approach of modern thermodynamics. Here we present a thermodynamic model of bipolarity that includes both homeostatic and oscillatory features and adds the most important feature of open systems thermodynamics: the creation of novel structures in bifurcation processes. According to the proposed model, bipolarity is the result of exaggerated biological energy that augments homeostatic, oscillatory and creative psychological processes. Only low-energy closed systems tend to rest ("point attractor") and entropic disorder. Open processes containing and exchanging energy fluctuate between opposite states ("periodic attractors"); they are characteristic of most physiological rhythms and are exaggerated in bipolar subjects. At higher energies, their strong fluctuations destroy pre-existing patterns and structures, produce turbulence ("chaotic attractors"), which sudden switches between opposite states, and create new and more complex structures. Likewise, high-energy bipolars develop high spontaneity, great fluctuations between opposite moods, internal and interpersonal chaos, and enhanced creativity (personal, artistic, professional) as well as psychopathology (personality deviations, psychotic delusions). Offered here is a theoretical explanation of the dual--creative and destructive--nature of bipolarity in terms of the new enantiodromic concept of entropy generalized by process theory. Clinically, this article offers an integrative model of bipolarity that accounts for many clinical features and contributes to a definition of the bipolar personality.

  20. Bipolar Electrode Sample Preparation Devices

    Science.gov (United States)

    Wang, Yi (Inventor); Song, Hongjun (Inventor); Pant, Kapil (Inventor)

    2017-01-01

    An analyte selection device can include: a body defining a fluid channel having a channel inlet and channel outlet; a bipolar electrode (BPE) between the inlet and outlet; one of an anode or cathode electrically coupled with the BPE on a channel inlet side of the BPE and the other of the anode or cathode electrically coupled with the BPE on a channel outlet side of the BPE; and an electronic system operably coupled with the anode and cathode so as to polarize the BPE. The fluid channel can have any shape or dimension. The channel inlet and channel outlet can be longitudinal or lateral with respect to the longitudinal axis of the channel. The BPE can be any metallic member, such as a flat plate on a wall or mesh as a barrier BPE. The anode and cathode can be located at a position that polarizes the BPE.

  1. Climatic factors and bipolar affective disorder

    DEFF Research Database (Denmark)

    Christensen, Ellen Margrethe; Larsen, Jens Knud; Gjerris, Annette

    2008-01-01

    In bipolar disorder, the factors provoking a new episode are unknown. As a seasonal variation has been noticed, it has been suggested that weather conditions may play a role. The aim of the study was to elucidate whether meteorological parameters influence the development of new bipolar phases....... A group of patients with at least three previous hospitalizations for bipolar disorder was examined every 3 months for up to 3 years. At each examination an evaluation of the affective phase was made according to the Hamilton Depression Scale (HAM-D(17)), and the Bech-Rafaelsen Mania Rating Scale (MAS......). In the same period, daily recordings from the Danish Meteorological Institute were received. We found no correlations between onset of bipolar episodes [defined as MAS score of 11 or more (mania) and as HAM-D(17) score of 12 or more (depression)] and any meteorological parameters. We found a statistical...

  2. Bipolar or unipolar? : A brain teasing question

    NARCIS (Netherlands)

    Rive, M.M.

    2017-01-01

    During the depressed or remitted states, major depressive disorder (MDD) and bipolar disorder (BD) are difficult to distinguish clinically. Treatments for both disorders differ, and inadequate treatment may lead to chronicity, poor psychosocial functioning, or even suicide. Although early

  3. Internet use by patients with bipolar disorder

    DEFF Research Database (Denmark)

    Bauer, Rita; Conell, Jörn; Glenn, Tasha

    2016-01-01

    There is considerable international interest in online education of patients with bipolar disorder, yet little understanding of how patients use the Internet and other sources to seek information. 1171 patients with a diagnosis of bipolar disorder in 17 countries completed a paper-based, anonymous...... survey. 81% of the patients used the Internet, a percentage similar to the general public. Older age, less education, and challenges in country telecommunications infrastructure and demographics decreased the odds of using the Internet. About 78% of the Internet users looked online for information...... on bipolar disorder or 63% of the total sample. More years of education in relation to the country mean, and feeling very confident about managing life decreased the odds of seeking information on bipolar disorder online, while having attended support groups increased the odds. Patients who looked online...

  4. Are rates of pediatric bipolar disorder increasing?

    DEFF Research Database (Denmark)

    Kessing, Lars Vedel; Vradi, Eleni; Andersen, Per Kragh

    2014-01-01

    Studies from the USA suggest that rates of pediatric bipolar disorder have increased since the mid-90s, but no study outside the USA has been published on the rates of pediatric bipolar disorder. Further, it is unclear whether an increase in rates reflects a true increase in the illness or more...... diagnostic attention. Using nationwide registers of all inpatients and outpatients contacts to all psychiatric hospitals in Denmark, we investigated (1) gender-specific rates of incident pediatric mania/bipolar disorder during a period from 1995 to 2012, (2) whether age and other characteristics...... for pediatric mania/bipolar disorder changed during the calendar period (1995 to 2003 versus 2004 to 2012), and (3) whether the diagnosis is more often made at first psychiatric contact in recent time compared to earlier according to gender. Totally, 346 patients got a main diagnosis of a manic episode (F30...

  5. Biological dysrhythm in remitted bipolar I disorder.

    Science.gov (United States)

    Iyer, Aishwarya; Palaniappan, Pradeep

    2017-12-01

    Recent treatment guidelines support treatment of biological rhythm abnormalities as a part of treatment of bipolar disorder, but still, literature examining various domains (Sleep, Activity, Social, and Eating) of biological rhythm and its clinical predictors are less. The main aim of our study is to compare various domains of biological rhythm among remitted bipolar I subjects and healthy controls. We also explored for any association between clinical variables and biological rhythm among bipolar subjects. 40 subjects with Bipolar I disorder and 40 healthy controls who met inclusion and exclusion criteria were recruited for the study. Diagnoses were ascertained by a qualified psychiatrist using MINI 5.0. Sociodemographic details, biological rhythm (BRIAN-Biological Rhythm Interview of assessment in Neuropsychiatry) and Sleep functioning (PSQI- Pittsburgh Sleep Quality Index) were assessed in all subjects. Mean age of the Bipolar subjects and controls were 41.25±11.84years and 38.25±11.25 years respectively. Bipolar subjects experienced more biological rhythm disturbance when compared to healthy controls (total BRIAN score being 34.25±9.36 vs 28.2±6.53) (p=0.002). Subsyndromal depressive symptoms (HDRS) had significant positive correlation with BRIAN global scores(r=0.368, p=0.02). Linear regression analysis showed that number of episodes which required hospitalization (β=0.601, t=3.106, P=0.004), PSQI (β=0.394, t=2.609, p=0.014), HDRS (β=0.376, t=2.34, t=0.036) explained 31% of variance in BRIAN scores in remitted bipolar subjects. Biological rhythm disturbances seem to persist even after clinical remission of bipolar illness. More studies to look into the impact of subsyndromal depressive symptoms on biological rhythm are needed. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Suicide in bipolar disorder: a review.

    Science.gov (United States)

    Latalova, Klara; Kamaradova, Dana; Prasko, Jan

    2014-06-01

    Suicide is a leading cause of death in patients with bipolar disorder. Risk factors and prevention of suicide in this illness are the focus of considerable current research. MEDLINE data base was searched for the key words "bipolar disorder" with "suicide", "lithium" with "suicide", "anticonvulsants" with "bipolar disorder", and "anticonvulsants" with "bipolar disorder" and with "suicide". No language or time constraints were applied. The lists of references were searched manually to find additional articles. It is estimated that 25% to 50% of patients with bipolar disorder will attempt suicide at least once over their lifetime, and that 8% to 19% will complete suicide. Mortality rates from cardiovascular diseases are elevated in bipolar disorder. Risk factors for suicide include younger age of onset of the illness, history of past suicidal behavior, family history of suicide acts, comorbid borderline personality disorder and substance use disorders, and hopelessness. The warning signs calling for immediate action include the patients threatening to harm themselves, or looking for ways to kill themselves (seeking access to pills or weapons), or the patient talking or writing about death. Robust evidence supports the effects of lithium treatment in reducing suicidal attempts and completions in bipolar disorder. The evidence for antisuicidal effects of anticonvulsants is weaker. Nevertheless, valproate and other anticonvulsants are frequently prescribed as mood stabilizers. There have been controversial suggestions that this treatment may elevate the risk of suicide, but the data supporting this are not convincing. Psychoeducation can reduce the number of suicide attempts and completions. Suicide in bipolar disorder is a major public health problem. Recent research has expanded our knowledge of risk factors and warning signs. Nevertheless, it appears that the introduction of lithium treatment in the 1970s was the most recent important breakthrough in the prevention

  7. Preparation of bipolar membranes by electrospinning

    International Nuclear Information System (INIS)

    Pan, Jiefeng; Hou, Linxiao; Wang, Qiuyue; He, Yubin; Wu, Liang; Mondal, Abhishek N.; Xu, Tongwen

    2017-01-01

    A new preparative pathway for the bipolar membranes was initiated via the electrospinning and hot-press process. The prepared bipolar membrane was consisting of sulfonated poly (phenylene oxide), polyethylene glycol, and quaternized poly (phenylene oxide). The above mentioned membrane was fabricated by the continuous electrospinning of the respective layer, followed by the solvent atmosphere treatment and hot-pressing, to obtain a transparent and dense structure. The thickness of each layer can be easily tuned by controlling the electrospinning parameters. The clear interfacial structure was observed and confirmed by the scanning electron microscope. The bipolar performance is evaluated by the current–voltage curves and production yield of acid and base. The final optimized bipolar membrane had similar yield of acid and base as the casting membrane. However, extremely lower potential drop value was observed when they are applied for the production of acid and base. The experimental results showed that, electrospinning is an effective and well controlled way to fabricate bipolar membranes, in which anion or cation exchange layer as well as interfacial layer can be easily changed or added as requested. - Highlights: • Bipolar membranes were prepared through electrospinning followed by post-treatment. • As-prepared membranes were successfully applied in electrodialysis for production of acid and base. • Electrospun membranes exhibit better performance than the casting ones.

  8. Preparation of bipolar membranes by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Jiefeng; Hou, Linxiao; Wang, Qiuyue; He, Yubin; Wu, Liang; Mondal, Abhishek N.; Xu, Tongwen, E-mail: twxu@ustc.edu.cn

    2017-01-15

    A new preparative pathway for the bipolar membranes was initiated via the electrospinning and hot-press process. The prepared bipolar membrane was consisting of sulfonated poly (phenylene oxide), polyethylene glycol, and quaternized poly (phenylene oxide). The above mentioned membrane was fabricated by the continuous electrospinning of the respective layer, followed by the solvent atmosphere treatment and hot-pressing, to obtain a transparent and dense structure. The thickness of each layer can be easily tuned by controlling the electrospinning parameters. The clear interfacial structure was observed and confirmed by the scanning electron microscope. The bipolar performance is evaluated by the current–voltage curves and production yield of acid and base. The final optimized bipolar membrane had similar yield of acid and base as the casting membrane. However, extremely lower potential drop value was observed when they are applied for the production of acid and base. The experimental results showed that, electrospinning is an effective and well controlled way to fabricate bipolar membranes, in which anion or cation exchange layer as well as interfacial layer can be easily changed or added as requested. - Highlights: • Bipolar membranes were prepared through electrospinning followed by post-treatment. • As-prepared membranes were successfully applied in electrodialysis for production of acid and base. • Electrospun membranes exhibit better performance than the casting ones.

  9. Comorbidity bipolar disorder and personality disorders.

    Science.gov (United States)

    Latalova, Klara; Prasko, Jan; Kamaradova, Dana; Sedlackova, Jana; Ociskova, Marie

    2013-01-01

    Outcome in bipolar patients can be affected by comorbidity of other psychiatric disorders. Comorbid personality disorders are frequent and may complicate the course of bipolar illness. We have much information about treating patients with uncomplicated bipolar disorder (BD) but much less knowledge about possibilities for patients with the comorbidity of BD and personality disorder. We conducted a series of literature searches using, as key words or as items in indexed fields, bipolar disorder and personality disorder or personality traits. Articles were obtained by searching MEDLINE from 1970 to 2012. In addition, we used other papers cited in articles from these searches, or cited in articles used in our own work. Tests of personality traits indicated that euthymic bipolar patients have higher scores on harm avoidance, reward dependence, and novelty seeking than controls. Elevation of novelty seeking in bipolar patients is associated with substance abuse comorbidity. Comorbidity with personality disorders in BD patients is associated with a more difficult course of illness (such as longer episodes, shorter time euthymic, and earlier age at onset) and an increase in comorbid substance abuse, suicidality and aggression. These problems are particularly pronounced in comorbidity with borderline personality disorder. Comorbidity with antisocial personality disorder elicits a similar spectrum of difficulties; some of the antisocial behavior exhibited by patients with this comorbidity is mediated by increased impulsivity.

  10. The role of sleep in bipolar disorder

    Directory of Open Access Journals (Sweden)

    Gold AK

    2016-06-01

    Full Text Available Alexandra K Gold,1 Louisa G Sylvia,1,2 1Department of Psychiatry, Massachusetts General Hospital, 2Harvard Medical School, Boston, MA, USA Abstract: Bipolar disorder is a serious mental illness characterized by alternating periods of elevated and depressed mood. Sleep disturbances in bipolar disorder are present during all stages of the condition and exert a negative impact on overall course, quality of life, and treatment outcomes. We examine the partnership between circadian system (process C functioning and sleep–wake homeostasis (process S on optimal sleep functioning and explore the role of disruptions in both systems on sleep disturbances in bipolar disorder. A convergence of evidence suggests that sleep problems in bipolar disorder result from dysregulation across both process C and process S systems. Biomarkers of depressive episodes include heightened fragmentation of rapid eye movement (REM sleep, reduced REM latency, increased REM density, and a greater percentage of awakenings, while biomarkers of manic episodes include reduced REM latency, greater percentage of stage I sleep, increased REM density, discontinuous sleep patterns, shortened total sleep time, and a greater time awake in bed. These findings highlight the importance of targeting novel treatments for sleep disturbance in bipolar disorder. Keywords: bipolar disorder, circadian rhythms, sleep–wake homeostasis

  11. Classification of cognitive performance in bipolar disorder.

    Science.gov (United States)

    Sparding, Timea; Silander, Katja; Pålsson, Erik; Östlind, Josefin; Ekman, Carl Johan; Sellgren, Carl M; Joas, Erik; Hansen, Stefan; Landén, Mikael

    2017-09-01

    To understand the etiology of cognitive impairment associated with bipolar disorder, we need to clarify potential heterogeneity in cognitive functioning. To this end, we used multivariate techniques to study if the correlation structure of cognitive abilities differs between persons with bipolar disorder and controls. Clinically stable patients with bipolar disorder (type I: n = 64; type II: n = 44) and healthy controls (n = 86) were assessed with a wide range of cognitive tests measuring executive function, speed, memory, and verbal skills. Data were analysed with multivariate techniques. A distinct subgroup (∼30%) could be identified that performed significantly poorer on tests concerning memory function. This cognitive phenotype subgroup did not differ from the majority of bipolar disorder patients with respect to other demographic or clinical characteristics. Whereas the majority of patients performed similar to controls, a subgroup of patients with bipolar disorder differed substantially from healthy controls in the correlation pattern of low-level cognitive abilities. This suggests that cognitive impairment is not a general trait in bipolar disorder but characteristic of a cognitive subgroup. This has important clinical implications for cognitive rehabilitation and remediation.

  12. O transtorno bipolar na mulher Bipolar disorder in women

    Directory of Open Access Journals (Sweden)

    Alexandro de Borja Gonçalves Guerra

    2005-01-01

    Full Text Available Diferenças sexuais, descritas em vários transtornos psiquiátricos, também parecem estar presentes no transtorno afetivo bipolar (TAB. A prevalência do TAB tipo I se distribui igualmente entre mulheres e homens. Mulheres parecem estar sujeitas a um risco maior de ciclagem rápida e mania mista, condições que fariam do TAB um transtorno com curso mais prejudicial no sexo feminino. Uma diátese depressiva mais marcante, uso excessivo de antidepressivos e diferenças hormonais surgem como hipóteses para explicar essas diferenças fenomenológicas, apesar das quais, mulheres e homens parecem responder igualmente ao tratamento medicamentoso. A indicação de anticonvulsivantes como primeira escolha em mulheres é controversa, a não ser para o tratamento da mania mista e, talvez, da ciclagem rápida. O tratamento do TAB na gravidez deve levar em conta tanto os riscos de exposição aos medicamentos quanto à doença materna. A profilaxia do TAB no puerpério está fortemente indicada em decorrência do grande risco de recorrência da doença nesse período. Embora, de modo geral, as medicações psicotrópicas estejam contra-indicadas durante a amamentação, entre os estabilizadores do humor, a carbamazepina e o valproato são mais seguros do que o lítio. Mais estudos são necessários para a confirmação das diferenças de curso do TAB entre mulheres e homens e a investigação de possíveis diferenças na efetividade dos tratamentos.Gender differences, described in several psychiatric disorders, seem to be also present in bipolar disorder (BD. The prevalence of bipolar I disorder is equally distributed between women and men. Women seem to be at higher risk for rapid cycling and mixed mania, conditions that could make BD a disorder with a more severe course in the female sex. A marked depressive diathesis among women, greatest use of antidepressants and hormonal differences have been mentioned as hypotheses to explain these

  13. Nebula--a web-server for advanced ChIP-seq data analysis.

    Science.gov (United States)

    Boeva, Valentina; Lermine, Alban; Barette, Camille; Guillouf, Christel; Barillot, Emmanuel

    2012-10-01

    ChIP-seq consists of chromatin immunoprecipitation and deep sequencing of the extracted DNA fragments. It is the technique of choice for accurate characterization of the binding sites of transcription factors and other DNA-associated proteins. We present a web service, Nebula, which allows inexperienced users to perform a complete bioinformatics analysis of ChIP-seq data. Nebula was designed for both bioinformaticians and biologists. It is based on the Galaxy open source framework. Galaxy already includes a large number of functionalities for mapping reads and peak calling. We added the following to Galaxy: (i) peak calling with FindPeaks and a module for immunoprecipitation quality control, (ii) de novo motif discovery with ChIPMunk, (iii) calculation of the density and the cumulative distribution of peak locations relative to gene transcription start sites, (iv) annotation of peaks with genomic features and (v) annotation of genes with peak information. Nebula generates the graphs and the enrichment statistics at each step of the process. During Steps 3-5, Nebula optionally repeats the analysis on a control dataset and compares these results with those from the main dataset. Nebula can also incorporate gene expression (or gene modulation) data during these steps. In summary, Nebula is an innovative web service that provides an advanced ChIP-seq analysis pipeline providing ready-to-publish results. Nebula is available at http://nebula.curie.fr/ Supplementary data are available at Bioinformatics online.

  14. A 'variable' stellar object in a variable blue nebula V-V 1-7

    International Nuclear Information System (INIS)

    Rao, N.K.; Gilra, D.P.

    1981-01-01

    V-V 1-7 is supposed to be one of the few planetary nebulae with Ao central stars and was included in the planetary-nebula catalogue as PK 235 + 1 0 1. The nebula was seen on the blue Palomar Observatory Sky Survey (POSS) print but not on the red print; as a result it was thought that it might be a reflection nebula. However, the symmetry of the nebula around the central star (HD 62001), and also the ultraviolet photometric variability of this central star led others to suggest that the nebula might be a nova shell. Subsequently it was found that the nebula V-V 1-7 has disappeared. It is not seen on any direct plate known to us except the POSS blue plate. In this paper the disappearance is reported (along with the nebula) of a stellar object, which appears within the 'nebular shell' of V-V 1-7 on the POSS blue plate, but not on the red plate. (author)

  15. Evolution of extra-galactic nebulae and the origin of metagalactic radio noise

    International Nuclear Information System (INIS)

    Bruce, C.E.R.

    1975-01-01

    It is pointed out that the discovery of the 'jet' in the radio source NGC 4486 fulfils a prediction made many years ago that such 'jets' would exist in some globular or elliptical nebulae. They are the channels of electrical discharges on a nebular scale then postulated, which will last for about 10 million years. It is emphasized that the discharge hypothesis would account for - 1. the existence of irregular nebulae; 2. the 'cataclysmic action' which Hubble regarded as required to account for the transition from nebulae of Type E to Type Sa; 3. the fact that the arms of spiral nebulae are never seen in process of formation; 4. the gathering of the matter towards the discharge channels by magnetic pinch effect; 5. the frequent occurrence of two diametrically opposed major arms; 6. the origin of radio waves throughout an extensive volume of space surrounding the 'jet' or discharge channel in NGC 4486; 7. the effect of one extra galactic nebula, NGC 3187, on another, NGC 3190; 8. the existence of diffuse patches of luminosity, 'emission nebulae', in the spiral arms of our own galaxy and in those of the 'Andromeda Nebula'. On the discharge theory about one per cent of all nebulae will be passing through the discharge phase at any one time, i.e., the number required to account for the observed intensity of metagalactic radio noise. (author)

  16. On planetary nebulae and Wolf-Rayet stars in the galactic-centre field

    International Nuclear Information System (INIS)

    Allen, D.A.

    1979-01-01

    A UK Schmidt objective-prism plate of the Galactic-centre field has been examined. Of the 74 objects in the field which have been catalogued as planetary nebulae, only half appear correctly classified; the others include Be stars, symbiotic stars, and stars without emission lines. A further 19 planetary nebulae and two Wolf-Rayet stars have been discovered. (author)

  17. Abundances of Planetary Nebulae IC 418, IC 2165 and NGC 5882

    NARCIS (Netherlands)

    Pottasch, [No Value; Bernard-Salas, J; Beintema, DA; Feibelman, WA

    The ISO and IUE spectra of the elliptical nebulae NGC 5882, IC 418 and IC 2165 are presented. These spectra are combined with the spectra in the visual wavelength region to obtain a complete, extinction corrected, spectrum. The chemical composition of the nebulae is then calculated and compared to

  18. Dark-Matter Content of Early-Type Galaxies with Planetary Nebulae

    NARCIS (Netherlands)

    Napolitano, N.R.; Romanowsky, A.J.; Coccato, L; Capaccioli, M.; Douglas, N.G.; Noordermeer, E.; Merrifield, M.R.; Kuijken, K.; Arnaboldi, M.; Gerhard, O.; Freeman, K.C.; De Lorenzi, F.; Das, P.

    2007-01-01

    Abstract. We examine the dark matter properties of nearby early-type galaxies using plane- tary nebulae (PNe) as mass probes. We have designed a specialised instrument, the Planetary Nebula Spectrograph (PN.S) operating at the William Herschel telescope, with the purpose of measuring PN velocities

  19. Characteristics of planetary nebulae and H II regions based on lambda = 1. 35 cm continuum measurements

    Energy Technology Data Exchange (ETDEWEB)

    Braz, M A; Jardim, J O; Kaufmann, P [Universidade Mackenzie, Sao Paulo (Brazil). Centro de Radio-Astronomia et Astrofisica

    1975-11-01

    Physical parameters are derived and discussed for stronger H II regions and planetary nebulae for which continuum radio data at lambda = 1.35 cm was obtained. The study includes southern hemisphere planetary nebulae IC-418, NGC-6,302, NGC-6,369, and H II regions RCW-65, RCW-87, RCW-99, H 2-3 and H 2-6.

  20. PPAK integral field spectroscopy survey of the Orion nebula. Data release

    NARCIS (Netherlands)

    Sánchez, S. F.; Cardiel, N.; Verheijen, M. A. W.; Martín-Gordón, D.; Vilchez, J. M.; Alves, J.

    2007-01-01

    Aims:We present a low-resolution spectroscopic survey of the Orion nebula. The data are released for public use. We show the possible applications of this dataset analyzing some of the main properties of the nebula. Methods: We perform an integral field spectroscopy mosaic of an area of ~5 arcmin× 6

  1. Planetary nebulae and Wolf-Rayet stars in the galactic-centre field

    Energy Technology Data Exchange (ETDEWEB)

    Allen, D A [Anglo-Australian Observatory, Epping (Australia)

    1979-06-01

    A UK Schmidt objective-prism plate of the Galactic-centre field has been examined. Of the 74 objects in the field which have been catalogued as planetary nebulae, only half appear correctly classified; the others include Be stars, symbiotic stars, and stars without emission lines. A further 19 planetary nebulae and two Wolf-Rayet stars have been discovered.

  2. Radio synthesis observations of planetary nebulae. II. A search for sub-arcsecond structure

    International Nuclear Information System (INIS)

    Balick, B.; Terzian, Y.

    1976-01-01

    Observations of 11 planetary nebulae with spatial resolutions from 0''.2 to 2'' at 2695 and 8085 MHz failed to show any very bright structure smaller than about 2''. The observations are shown to be consistent with the present understanding of the temperatures and density distributions thought to typify most planetary nebulae

  3. Broadband x-ray imaging and spectroscopy of the crab nebula and pulsar with NuSTAR

    DEFF Research Database (Denmark)

    Madsen, Kristin K.; Reynolds, Stephen; Harrison, Fiona

    2015-01-01

    We present broadband (3-78 keV) NuSTAR X-ray imaging and spectroscopy of the Crab nebula and pulsar. We show that while the phase-averaged and spatially integrated nebula + pulsar spectrum is a power law in this energy band, spatially resolved spectroscopy of the nebula finds a break at ~9 ke...

  4. Clinical, Demographic, and Familial Correlates of Bipolar Spectrum Disorders among Offspring of Parents with Bipolar Disorder

    Science.gov (United States)

    Goldstein, Benjamin I.; Shamseddeen, Wael; Axelson, David A.; Kalas, Cathy; Monk, Kelly; Brent, David A.; Kupfer, David J.; Birmaher, Boris

    2010-01-01

    Objective: Despite increased risk, most offspring of parents with bipolar disorder (BP) do not manifest BP. The identification of risk factors for BP among offspring could improve preventive and treatment strategies. We examined this topic in the Pittsburgh Bipolar Offspring Study (BIOS). Method: Subjects included 388 offspring, ages 7-17 years,…

  5. Cooling and quasi-static contraction of the primitive solar nebula after gas accretion

    International Nuclear Information System (INIS)

    Watanabe, Seichiro; Nakagawa, Yoshitsugu; Nakazawa, Kiyoshi

    1990-01-01

    The evolution of the primitive solar nebula in the quasi-static contraction phase where the nebula cools down toward the thermal steady state is studied. The solar irradiation onto the nebula keeps the surface temperature constant, so that the convective ozone retreats from the surface as the nebula cools. Thus if thermal convection is the only source of turbulence, convection will quiet down in an early time of the cooling. Afterward, the nebula evolves toward an isothermal structure in a time scale of 1000 yr. The cooling rates in the vicinity of the midplate at 1 AU are 0.003 K/hr at T(c) = 1000 K and 3 x 10 to the -5th K/hr at T(c) = 300 K for the standard model. If some turbulence exists irrespective of convection, convection may continue for sufficiently strong turbulent heating. 39 refs

  6. Helium shell flashes and ionization of planetary nebulae. Pt. 2. FG Sge

    International Nuclear Information System (INIS)

    Tylenda, R.

    1980-01-01

    Theoretical models have been constructed to study time-dependent effects in the nebulae (He 1-5) associated with FG Sge. Two cases have been considered: recombination of an initially stationary nebula of moderate excitation (Case A), and nonequilibrium ionization (and subsequent recombination) of an initially neutral nebula by a thermal pulse in the central star (Case B). Comparison with the observed spectrum does not allow to distinguish definitely between both cases. There are slight indications that the present state of He 1-5 is better reproduced in Case B which is also preferable from the point of view of the present theoretical knowledge of observational appearances of helium shell flashes in planetary nebula nuclei. The nebula has a normal chemical composition. (author)

  7. Emission lines of Mg2 and Ca2 in planetary nebulae

    International Nuclear Information System (INIS)

    Gurzadyan, G.A.

    1979-01-01

    Conditions of exciting resonance lines in the emission of ionized magnesium (lambda lambda 2796+2803 Mg2) and calcium (lambda lambda 3934+3968 Ca2) in planetary nebulae have been analyzed. It is shown that the allowed lines are excited with the same mechanism, as the forbidden lines, i.e. inelastic electron collisions, but not with common fluorescence. The emission line lambda 2800 Mg2 of enough force can be observed only in the spectra of planetary nebulae with mean excitation (IC 2149) as well as in the spectra of diffuse nebulae. The line must not be observed in high-excited planetary nebulae (NGC 7026, 7662). The absence of emission lines H and K Ca2 in planetary nebulae spectra results from the fact, that their expected intensity is by 3-4 orders less than the intensity of the line lambda 2800 Mg2 or Hsub(β) hydrogen

  8. [Circadian markers and genes in bipolar disorder].

    Science.gov (United States)

    Yeim, S; Boudebesse, C; Etain, B; Belliviera, F

    2015-09-01

    Bipolar disorder is a severe and complex multifactorial disease, characterized by alternance of acute episodes of depression and mania/hypomania, interspaced by euthymic periods. The etiological determinants of bipolar disorder yet, are still poorly understood. For the last 30 years, chronobiology is an important field of investigation to better understand the pathophysiology of bipolar disorder. We conducted a review using Medline, ISI Database, EMBase, PsyInfo up to January 2015, using the following keywords combinations: "mood disorder", "bipolar disorder", "depression", "unipolar disorder", "major depressive disorder", "affective disorder", for psychiatric conditions; and "circadian rhythms", "circadian markers", "circadian gene", "clock gene", "melatonin" for circadian rhythms. The search critera was presence of word in any field of the article. Quantitative and qualitative circadian abnormalities are associated with bipolar disorders both during acute episodes and euthymic periods, suggesting that these altered circadian rhythms may represent biological trait markers of the disorder. These circadian dysfunctions were assessed by various validated tools including polysomnography, actigraphy, sleep diaries, chronotype assessments and blood melatonin/cortisol measures. Other altered endogenous circadian activities have also been reported in bipolar patients, such as hormones secretion, core body temperature or fibroblasts activity. Moreover, these markers were also altered in healthy relatives of bipolar patients, suggesting a degree of heritability. Several genetic association studies have also showed associations between multiple circadian genes and bipolar disorder, such as CLOCK, ARTNL1, GSK3β, PER3, NPAS2, NR1D1, TIMELESS, RORA, RORB, and CSNK1ε. Thus, these circadian gene variants may contribute to the genetic susceptibility of the disease. Furthermore, the study of the clock system may help to better understand some phenotypic aspects like the

  9. Decision making in euthymic bipolar I and bipolar II disorders.

    Science.gov (United States)

    Martino, D J; Strejilevich, S A; Torralva, T; Manes, F

    2011-06-01

    The main aim of this study was to compare a large population of patients with bipolar disorder (BD) types I and II strictly defined as euthymic with healthy controls on measures of decision making. An additional aim was to compare performance on a decision-making task between patients with and without a history of suicide attempt. Eighty-five euthymic patients with BD-I or BD-II and 34 healthy controls were included. All subjects completed tests to assess verbal memory, attention and executive functions, and a decision-making paradigm (the Iowa Gambling Task, IGT). Both groups of patients had worse performance than healthy controls on measures of verbal memory, attention and executive function. No significant differences were found between BD-I, BD-II and healthy controls on measures of decision making. By contrast, patients with a history of suicide attempt had lower performance in the IGT than patients without a history of suicide attempt. Patients with euthymic BD-I and BD-II had intact decision-making abilities, suggesting that this does not represent a reliable trait marker of the disorder. In addition, our results provide further evidence of an association between impairments in decision making and vulnerability to suicidal behavior.

  10. Nebula: reconstruction and visualization of scattering data in reciprocal space.

    Science.gov (United States)

    Reiten, Andreas; Chernyshov, Dmitry; Mathiesen, Ragnvald H

    2015-04-01

    Two-dimensional solid-state X-ray detectors can now operate at considerable data throughput rates that allow full three-dimensional sampling of scattering data from extended volumes of reciprocal space within second to minute time-scales. For such experiments, simultaneous analysis and visualization allows for remeasurements and a more dynamic measurement strategy. A new software, Nebula , is presented. It efficiently reconstructs X-ray scattering data, generates three-dimensional reciprocal space data sets that can be visualized interactively, and aims to enable real-time processing in high-throughput measurements by employing parallel computing on commodity hardware.

  11. Interstellar Organics, the Solar Nebula, and Saturn's Satellite Phoebe

    Science.gov (United States)

    Pendleton, Y. J.; Cruikshank, D. P.

    2014-01-01

    The diffuse interstellar medium inventory of organic material (Pendleton et al. 1994, Pendleton & Allamandola 2002) was likely incorporated into the molecular cloud in which the solar nebula condensed. This provided the feedstock for the formation of the Sun, major planets, and the smaller icy bodies in the region outside Neptune's orbit (transneptunian objects, or TNOs). Saturn's satellites Phoebe, Iapetus, and Hyperion open a window to the composition of one class of TNO as revealed by the near-infrared mapping spectrometer (VIMS) on the Cassini spacecraft at Saturn. Phoebe (mean diameter 213 km) is a former TNO now orbiting Saurn. VIMS spaectral maps of PHoebe's surface reveal a complex organic spectral signature consisting of prominent aromatic (CH) and alophatic hydrocarbon (CH2, CH3) absorption bands (3.2-3.6 micrometers). Phoebe is the source of a huge debris ring encircling Saturn, and from which particles (approximately 5-20 micrometer size) spiral inward toward Saturn. They encounter Iapetus and Hperion where they mix with and blanket the native H2O ice of those two bodies. Quantitative analysis of the hydrocarbon bands on Iapetus demonstrates that aromatic CH is approximately 10 times as abundant as aliphatic CH2+CH3, significantly exceeding the strength of the aromatic signature in interplanetary dust particles, comet particles, ad in carbonaceous meteorites (Cruikshank et al. 2013). A similar excess of aromatics over aliphatics is seen in the qualitative analysis of Hyperion and Phoebe itself (Dalle Ore et al. 2012). The Iapetus aliphatic hydrocarbons show CH2/CH3 approximately 4, which is larger than the value found in the diffuse ISM (approximately 2-2.5). In so far as Phoebe is a primitive body that formed in the outer regions of the solar nebula and has preserved some of the original nebula inventory, it can be key to understanding the content and degree of procesing of the nebular material. There are other Phoebe-like TNOs that are presently

  12. Stellar outflow: relative motions of nebulae and Of stars

    International Nuclear Information System (INIS)

    Lynds, B.T.

    1979-01-01

    On the basis of arguments presented by Roberts (1972) and of Shu et al. (1972), Minn and Greenberg (1973) argued that the velocity differences between newly formed hot stars and the surrounding interstellar medium are sufficiently different so that typical H II regions should consist of material which is continually being replaced by the ambient medium and which should therefore possess the velocity of the medium rather than that of the star. The critical test of this hypothesis will be a comparison of nebular velocities with the velocities of the exciting stars. This is performed for Of stars and nebulae. (Auth.)

  13. Pulsating stars in the region of Carina Nebula

    Energy Technology Data Exchange (ETDEWEB)

    Steslicki, Marek [Astronomical Institute, University of Wroclaw (Poland)], E-mail: steslicki@astro.uni.wroc.p1

    2008-10-15

    We present the results of a search for pulsating stars in the region of Carina Nebula which includes three very young open clusters: Trumpler 14, 15 and 16. The search was made with the Wide Field Imager (WFI) on the MPG/ESO 2.2-m telescope in La Silla (Chile). In total, about 16,000 stars have been analyzed using classical Fourier techniques. We found over 20 pulsating {delta}-Scuti type stars in this region. Most of them are probable members of open clusters at the pre-main sequence evolutionary stage.

  14. Model atmospheres and parameters of central stars of planetary nebulae

    International Nuclear Information System (INIS)

    Patriarchi, P.; Cerruti-sola, M.; Perinotto, M.

    1989-01-01

    Non-LTE hydrogen and helium model atmospheres have been obtained for temperatures and gravities relevant to the central stars of planetary nebulae. Low-resolution and high-resolution observations obtained by the IUE satellite have been used along with optical data to determine Zanstra temperatures of the central stars of NGC 1535, NGC 6210, NGC 7009, IC 418, and IC 4593. Comparison of the observed stellar continuum of these stars with theoretical results allowed further information on the stellar temperature to be derived. The final temperatures are used to calculate accurate stellar parameters. 62 refs

  15. Flare stars of the Orion Nebula - spectra of an outburst

    International Nuclear Information System (INIS)

    Carter, B.D.; O'Mara, B.J.; Ross, J.E.

    1988-01-01

    For the first time, detailed, time-resolved spectra of a flare event of an Orion cluster flare star are presented. These spectra, covering ∼ λλ3600-4600, were obtained by using the Anglo-Australian Telescope with a fibre coupler to simultaneously monitor 23 flare stars in the region of the Orion Nebula. The flare spectra reveal continuous emission which filled in the photospheric Ca I 4226 A absorption, and hydrogen Balmer, Ca II H and K, He I 4026 A and He I 4471 A line emission. Overall, the spectral behaviour indicates similarities to strong outbursts of the classical dMe flare stars. (author)

  16. Bi-Abundance Ionisation Structure of the Wolf-Rayet Planetary Nebula PB 8

    Science.gov (United States)

    Danehkar, A.

    2018-01-01

    The planetary nebula PB 8 around a [WN/WC]-hybrid central star is one of planetary nebulae with moderate abundance discrepancy factors (ADFs 2-3), which could be an indication of a tiny fraction of metal-rich inclusions embedded in the nebula (bi-abundance). In this work, we have constructed photoionisation models to reproduce the optical and infrared observations of the planetary nebula PB 8 using a non-LTE stellar model atmosphere ionising source. A chemically homogeneous model initially used cannot predict the optical recombination lines. However, a bi-abundance model provides a better fit to most of the observed optical recombination lines from N and O ions. The metal-rich inclusions in the bi-abundance model occupy 5.6% of the total volume of the nebula, and are roughly 1.7 times cooler and denser than the mean values of the surrounding nebula. The N/H and O/H abundance ratios in the metal-rich inclusions are 1.0 and 1.7 dex larger than the diffuse warm nebula, respectively. To reproduce the Spitzer spectral energy distribution of PB 8, dust grains with a dust-to-gas ratio of 0.01 (by mass) were also included. It is found that the presence of metal-rich inclusions can explain the heavy element optical recombination lines, while a dual-dust chemistry with different grain species and discrete grain sizes likely produces the infrared continuum of this planetary nebula. This study demonstrates that the bi-abundance hypothesis, which was examined in a few planetary nebulae with large abundance discrepancies (ADFs > 10), could also be applied to those typical planetary nebulae with moderate abundance discrepancies.

  17. The International Society for Bipolar Disorders (ISBD) Task Force Report on Antidepressant Use in Bipolar Disorders

    Science.gov (United States)

    Pacchiarotti, Isabella; Bond, David J.; Baldessarini, Ross J.; Nolen, Willem A.; Grunze, Heinz; Licht, Rasmus W.; Post, Robert M.; Berk, Michael; Goodwin, Guy M.; Sachs, Gary S.; Tondo, Leonardo; Findling, Robert L.; Youngstrom, Eric A.; Tohen, Mauricio; Undurraga, Juan; González-Pinto, Ana; Goldberg, Joseph F.; Yildiz, Ayşegül; Altshuler, Lori L.; Calabrese, Joseph R.; Mitchell, Philip B.; Thase, Michael E.; Koukopoulos, Athanasios; Colom, Francesc; Frye, Mark A.; Malhi, Gin S.; Fountoulakis, Konstantinos N.; Vázquez, Gustavo; Perlis, Roy H.; Ketter, Terence A.; Cassidy, Frederick; Akiskal, Hagop; Azorin, Jean-Michel; Valentí, Marc; Mazzei, Diego Hidalgo; Lafer, Beny; Kato, Tadafumi; Mazzarini, Lorenzo; Martínez-Aran, Anabel; Parker, Gordon; Souery, Daniel; Özerdem, Ayşegül; McElroy, Susan L.; Girardi, Paolo; Bauer, Michael; Yatham, Lakshmi N.; Zarate, Carlos A.; Nierenberg, Andrew A.; Birmaher, Boris; Kanba, Shigenobu; El-Mallakh, Rif S.; Serretti, Alessandro; Rihmer, Zoltan; Young, Allan H.; Kotzalidis, Georgios D.; MacQueen, Glenda M.; Bowden, Charles L.; Ghaemi, S. Nassir; Lopez-Jaramillo, Carlos; Rybakowski, Janusz; Ha, Kyooseob; Perugi, Giulio; Kasper, Siegfried; Amsterdam, Jay D.; Hirschfeld, Robert M.; Kapczinski, Flávio; Vieta, Eduard

    2014-01-01

    Objective The risk-benefit profile of antidepressant medications in bipolar disorder is controversial. When conclusive evidence is lacking, expert consensus can guide treatment decisions. The International Society for Bipolar Disorders (ISBD) convened a task force to seek consensus recommendations on the use of antidepressants in bipolar disorders. Method An expert task force iteratively developed consensus through serial consensus-based revisions using the Delphi method. Initial survey items were based on systematic review of the literature. Subsequent surveys included new or reworded items and items that needed to be rerated. This process resulted in the final ISBD Task Force clinical recommendations on antidepressant use in bipolar disorder. Results There is striking incongruity between the wide use of and the weak evidence base for the efficacy and safety of antidepressant drugs in bipolar disorder. Few well-designed, long-term trials of prophylactic benefits have been conducted, and there is insufficient evidence for treatment benefits with antidepressants combined with mood stabilizers. A major concern is the risk for mood switch to hypomania, mania, and mixed states. Integrating the evidence and the experience of the task force members, a consensus was reached on 12 statements on the use of antidepressants in bipolar disorder. Conclusions Because of limited data, the task force could not make broad statements endorsing antidepressant use but acknowledged that individual bipolar patients may benefit from antidepressants. Regarding safety, serotonin reuptake inhibitors and bupropion may have lower rates of manic switch than tricyclic and tetracyclic antidepressants and norepinephrine-serotonin reuptake inhibitors. The frequency and severity of antidepressant-associated mood elevations appear to be greater in bipolar I than bipolar II disorder. Hence, in bipolar I patients antidepressants should be prescribed only as an adjunct to mood-stabilizing medications

  18. Bipolar postpartum depression: An update and recommendations.

    Science.gov (United States)

    Sharma, Verinder; Doobay, Minakshi; Baczynski, Christine

    2017-09-01

    Over the past few years there has been a surge of interest in the study of bipolar postpartum depression (PPD); however, questions remain about its prevalence, screening, clinical features, and treatment. Three electronic databases, MEDLINE/PubMed (1966-2016), PsycINFO (1806-2016), and the Cochrane Database of Systematic Reviews, were searched using a combination of the keywords bipolar, depression, postpartum, peripartum, prevalence, screening, diagnosis, treatment, drugs, and psychotherapy. The reference lists of articles identified were also searched. All relevant articles published in English were included. Depending on the population studied, 21.4-54% of women with PPD have a diagnosis of bipolar disorder (BD). Characteristic clinical features include younger age at illness onset, first onset of depression after childbirth, onset immediately after delivery, atypical depressive symptoms, psychotic features, mixed features, and history of BD in first-degree family members. Treatment should be guided by symptom acuity, safety concerns, the patient's response to past treatments, drug tolerability, and breastfeeding preference. In the absence of controlled treatment data, preference should be given to drugs normally indicated for bipolar depression including lithium, quetiapine and lamotrigine. Although antidepressants have been studied in combination with mood stabilizers in bipolar depression, these drugs should be avoided due to likelihood of elevated risk of induction of manic symptoms in the postpartum period. In the postpartum period, bipolar PPD is common, can be differentiated from unipolar PPD, and needs to be identified promptly in order to expedite appropriate treatment. Future studies on pharmacotherapy and psychotherapy should focus on the acute and preventative treatment of bipolar PPD. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Anxiety, stress and perfectionism in bipolar disorder.

    Science.gov (United States)

    Corry, Justine; Green, Melissa; Roberts, Gloria; Frankland, Andrew; Wright, Adam; Lau, Phoebe; Loo, Colleen; Breakspear, Michael; Mitchell, Philip B

    2013-12-01

    Previous reports have highlighted perfectionism and related cognitive styles as a psychological risk factor for stress and anxiety symptoms as well as for the development of bipolar disorder symptoms. The anxiety disorders are highly comorbid with bipolar disorder but the mechanisms that underpin this comorbidity are yet to be determined. Measures of depressive, (hypo)manic, anxiety and stress symptoms and perfectionistic cognitive style were completed by a sample of 142 patients with bipolar disorder. Mediation models were used to explore the hypotheses that anxiety and stress symptoms would mediate relationships between perfectionistic cognitive styles, and bipolar disorder symptoms. Stress and anxiety both significantly mediated the relationship between both self-critical perfectionism and goal attainment values and bipolar depressive symptoms. Goal attainment values were not significantly related to hypomanic symptoms. Stress and anxiety symptoms did not significantly mediate the relationship between self-critical perfectionism and (hypo)manic symptoms. 1. These data are cross-sectional; hence the causality implied in the mediation models can only be inferred. 2. The clinic patients were less likely to present with (hypo)manic symptoms and therefore the reduced variability in the data may have contributed to the null findings for the mediation models with (hypo) manic symptoms. 3. Those patients who were experiencing current (hypo)manic symptoms may have answered the cognitive styles questionnaires differently than when euthymic. These findings highlight a plausible mechanism to understand the relationship between bipolar disorder and the anxiety disorders. Targeting self-critical perfectionism in the psychological treatment of bipolar disorder when there is anxiety comorbidity may result in more parsimonious treatments. © 2013 Published by Elsevier B.V.

  20. Big data for bipolar disorder.

    Science.gov (United States)

    Monteith, Scott; Glenn, Tasha; Geddes, John; Whybrow, Peter C; Bauer, Michael

    2016-12-01

    The delivery of psychiatric care is changing with a new emphasis on integrated care, preventative measures, population health, and the biological basis of disease. Fundamental to this transformation are big data and advances in the ability to analyze these data. The impact of big data on the routine treatment of bipolar disorder today and in the near future is discussed, with examples that relate to health policy, the discovery of new associations, and the study of rare events. The primary sources of big data today are electronic medical records (EMR), claims, and registry data from providers and payers. In the near future, data created by patients from active monitoring, passive monitoring of Internet and smartphone activities, and from sensors may be integrated with the EMR. Diverse data sources from outside of medicine, such as government financial data, will be linked for research. Over the long term, genetic and imaging data will be integrated with the EMR, and there will be more emphasis on predictive models. Many technical challenges remain when analyzing big data that relates to size, heterogeneity, complexity, and unstructured text data in the EMR. Human judgement and subject matter expertise are critical parts of big data analysis, and the active participation of psychiatrists is needed throughout the analytical process.

  1. Bipolar pulse generator for intense pulsed ion beam accelerator

    International Nuclear Information System (INIS)

    Ito, H.; Igawa, K.; Kitamura, I.; Masugata, K.

    2007-01-01

    A new type of pulsed ion beam accelerator named ''bipolar pulse accelerator'' (BPA) has been proposed in order to improve the purity of intense pulsed ion beams. To confirm the principle of the BPA, we developed a bipolar pulse generator for the bipolar pulse experiment, which consists of a Marx generator and a pulse forming line (PFL) with a rail gap switch on its end. In this article, we report the first experimental result of the bipolar pulse and evaluate the electrical characteristics of the bipolar pulse generator. When the bipolar pulse generator was operated at 70% of the full charge condition of the PFL, the bipolar pulse with the first (-138 kV, 72 ns) and the second pulse (+130 kV, 70 ns) was successfully obtained. The evaluation of the electrical characteristics indicates that the developed generator can produce the bipolar pulse with fast rise time and sharp reversing time

  2. Application of Bipolar Fuzzy Sets in Graph Structures

    Directory of Open Access Journals (Sweden)

    Muhammad Akram

    2016-01-01

    Full Text Available A graph structure is a useful tool in solving the combinatorial problems in different areas of computer science and computational intelligence systems. In this paper, we apply the concept of bipolar fuzzy sets to graph structures. We introduce certain notions, including bipolar fuzzy graph structure (BFGS, strong bipolar fuzzy graph structure, bipolar fuzzy Ni-cycle, bipolar fuzzy Ni-tree, bipolar fuzzy Ni-cut vertex, and bipolar fuzzy Ni-bridge, and illustrate these notions by several examples. We study ϕ-complement, self-complement, strong self-complement, and totally strong self-complement in bipolar fuzzy graph structures, and we investigate some of their interesting properties.

  3. Cardiovascular risk factors in outpatients with bipolar disorder

    NARCIS (Netherlands)

    Klumpers, U.M.H.; Boom, K.; Janssen, F.M.G.; Tulen, J.H.M.; Loonen, Anton J. M.

    2004-01-01

    Background: The mortality due to cardiovascular diseases in bipolar patients is much higher than in the general population. It is unclear whether lithium treatment contributes to this cardiovascular morbidity. Methods: The cardiovascular risk factors in outpatients with bipolar disorder on

  4. Cytokines in bipolar disorder vs. healthy control subjects

    DEFF Research Database (Denmark)

    Munkholm, Klaus; Braüner, Julie Vestergaard; Kessing, Lars Vedel

    2013-01-01

    Bipolar disorder may be associated with peripheral immune system dysfunction; however, results in individual studies are conflicting. Our aim was to systematically review evidence of peripheral cytokine alterations in bipolar disorder integrating findings from various affective states....

  5. Assessment of subjective and objective cognitive function in bipolar disorder

    DEFF Research Database (Denmark)

    Demant, Kirsa M; Vinberg, Maj; Kessing, Lars V

    2015-01-01

    Cognitive dysfunction is prevalent in bipolar disorder (BD). However, the evidence regarding the association between subjective cognitive complaints, objective cognitive performance and psychosocial function is sparse and inconsistent. Seventy seven patients with bipolar disorder who presented...

  6. Smartphone-based objective monitoring in bipolar disorder

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria; Bauer, Michael; Kessing, Lars Vedel

    2018-01-01

    , anxiety, substance abuse, eating disorder, schizophrenia and bipolar disorder have been developed and used. The present paper presents the status and findings from studies using automatically generated objective smartphone data in the monitoring of bipolar disorder, and addresses considerations...

  7. Immune activation by casein dietary antigens in bipolar disorder

    NARCIS (Netherlands)

    Severance, E.G.; Dupont, D.; Dickerson, F.B.; Stallings, C.R.; Origoni, A.E.; Krivogorsky, B.; Yang, S.; Haasnoot, W.; Yolken, R.H.

    2010-01-01

    Objectives: Inflammation and other immune processes are increasingly linked to psychiatric diseases. Antigenic triggers specific to bipolar disorder are not yet defined. We tested whether antibodies to bovine milk caseins were associated with bipolar disorder, and whether patients recognized

  8. Bipolar disorder: an update | Outhoff | South African Family Practice

    African Journals Online (AJOL)

    Bipolar disorder, characterised by alternating discrete episodes of (hypo)mania and depression, provides unique diagnostic and treatment challenges. Updated diagnostic (DSM-5) and current pharmacological treatment recommendations are briefly reviewed here. Keywords: bipolar disorder; diagnosis; evidence-based ...

  9. Ionization structure of planetary nebulae. Part 8: NGC 6826

    International Nuclear Information System (INIS)

    Barker, T.

    1987-01-01

    Spectrophotometric observations of emission-line intensities over the spectral range 1400 to 1700 A were made in seven positions in the planetary nebulae NCG 6826. The O(++) electron temperature varies little from 8900 K throughout the nebula; the Balmer continuum electron temperature averages 1500 K higher. The wavelength 4267 C II line intensities imply C(++) abundances that are systematically higher than those determined from the wavelength 1906, 1909 C III lines, but because of uncertainties in the intensities of the ultraviolet lines relative to the optical ones, this discrepancy is less conclusively demonstrated in NGC 6826 than in other planetaries in this series. Standard equations used to correct for the existence of elements in other than the optically observable ionization stages give results that are consistent and also in approximate agreement with abundances calculated using ultraviolet lines in the few cases where the relevant ultraviolet lines are measurable. The results of the logarithmic abundances differ somewhat from the recent study by Aller and Czyzak, in part because their measured electron temperatures are somewhat higher. The Ar, Ne, and, to some extent, O and S abundances appear to be somewhat low, suggesting that the progenitor to NGC 6826 like that to NGC 7662, may have formed out of somewhat metal-poor material

  10. Broad Halpha Wing Formation in the Planetary Nebula IC 4997.

    Science.gov (United States)

    Lee; Hyung

    2000-02-10

    The young and compact planetary nebula IC 4997 is known to exhibit very broad wings with a width exceeding 5000 km s-1 around Halpha. We propose that the broad wings are formed through Rayleigh-Raman scattering that involves atomic hydrogen, by which Lybeta photons with a velocity width of a few 102 km s-1 are converted to optical photons and fill the Halpha broad wing region. The conversion efficiency reaches 0.6 near the line center, where the scattering optical depth is much larger than 1, and rapidly decreases in the far wings. Assuming that close to the central star there exists an unresolved inner compact core of high density, nH approximately 109-1010 cm-3, we use the photoionization code "CLOUDY" to show that sufficient Lybeta photons for scattering are produced. Using a top-hat-incident profile for the Lybeta flux and a scattering region with a H i column density NHi=2x1020 cm-2 and a substantial covering factor, we perform a profile-fitting analysis in order to obtain a satisfactory fit to the observed flux. We briefly discuss the astrophysical implications of the Rayleigh-Raman processes in planetary nebulae and other emission objects.

  11. The remarkably high excitation planetary nebula GC 6537.

    Science.gov (United States)

    Aller, L H; Hung, S; Feibelman, W A

    1999-05-11

    NGC 6537 is an unusually high excitation point symmetric planetary nebula with a rich spectrum. Its kinematical structures are of special interest. We are here primarily concerned with the high resolution spectrum as revealed by the Hamilton echelle Spectrograph at Lick Observatory (resolution approximately 0.2 A) and supplemented by UV and near-UV data. These extensive data permit a determination of interstellar extinction, plasma diagnostics, and ionic concentrations. The photoionization models that have been used successfully for many planetary nebulae are not entirely satisfactory here. The plasma electron temperature of a photoionization model cannot much exceed 20,000 K, but plasma diagnostics show that regions emitting radiation of highly ionized atoms such as [NeIV] and [NeV] are much hotter, showing that shock excitation must be important, as suggested by the remarkable kinematics of this object. Hence, instead of employing a strict photoionization model, we are guided by the nebular diagnostics, which reveal how electron temperature varies with ionization potential and accommodates density effects. The predictions of the photoionization model may be useful in estimating ionization correction factor. In effect, we have estimated the chemical composition by using both photoionization and shock considerations.

  12. Planetesimal Sizes and Mars Formation in the Magnetized Solar Nebula

    Science.gov (United States)

    Hasegawa, Yasuhiro; Morishima, Ryuji

    2017-10-01

    The Hf-W chronology inferred from Martian meteorites suggests that Mars should be a stranded planetary embryo formed within a very short (about 2 Myr) accretion timescale. Previous studies show that such rapid growth can be realized when small (nebular evolution. Under this circumstance, impact velocity of planetesimals can be very high due to nebular density fluctuations caused by turbulence, and hence collisions between small planetesimals can become destructive, rather than mergers. Here, we investigate how Mars formed in the magnetized solar nebula, focusing on MHD turbulence. We demonstrate what mass of planetesimals can contribute to Mars formation and what value of the nebular mass is needed to satisfy the rapid accretion timescale. We therefore derive a more realistic condition of the solar nebula under which Mars formation took place. While this study is based on the standard picture of runaway and oligarchic growth, we also discuss other formation mechanisms in order to compare how our results would be consistent with the properties of the solar system. These mechanisms are a hypothesis that Mars formed from a narrow ring of planetesimals, and the pebble accretion scenario.

  13. The Crab nebula's ''wisps'' as shocked pulsar wind

    International Nuclear Information System (INIS)

    Gallant, Y.A.; Arons, J.; Langdon, A.B.

    1992-01-01

    The Crab synchrotron nebula has been successfully modelled as the post-shock region of a relativistic, magnetized wind carrying most of the spindown luminosity from the central pulsar. While the Crab is the best-studied example, most of the highest spindown luminosity pulsars are also surrounded by extended synchrotron nebulae, and several additional supernova remnants with ''plerionic'' morphologies similar to the Crab are known where the central object is not seen. All these objects have nonthermal, power-law spectra attributable to accelerated high-energy particles thought to originate in a Crab-like relativistic pulsar wind. However, proposed models have so far treated the wind shock as an infinitesimally thin discontinuity, with an arbitrarily ascribed particle acceleration efficiency. To make further progress, investigations resolving the shock structure seemed in order. Motivated by these considerations, we have performed ''particle-in-cell (PIC) simulations of perpendicularly magnetized shocks in electron-positron and electron-positron-ion plasmas. The shocks in pure electron-positron plasmas were found to produce only thermal distributions downstream, and are thus poor candidates as particle acceleration sites. When the upstream plasma flow also contained a smaller population of positive ions, however, efficient acceleration of positrons, and to a lesser extent of electrons, was observed in the simulations

  14. Photoionization modeling of Magellanic Cloud planetary nebulae. I

    Science.gov (United States)

    Dopita, M. A.; Meatheringham, S. J.

    1991-01-01

    The results of self-consistent photoionization modeling of 38 Magellanic Cloud PNe are presented and used to construct an H-R diagram for the central stars and to obtain both the nebular chemical abundances and the physical parameters of the nebulae. T(eff)s derived from nebular excitation analysis are in agreement with temperatures derived by the classical Zanstra method. There is a linear correlation between log T(eff) and the excitation class. The majority of the central stars in the sample with optically thick nebulae have masses between 0.55 and 0.7 solar mass and are observed during their hydrogen-burning excursion toward high temperatures. Optically thin objects are found scattered throughout the H-R diagram, but tend to have a somewhat smaller mean mass. Type I PN are found to have high core masses and to lie on the descending branch of the evolutionary tracks. The nebular mass of the optically thick objects is closely related to the nebular radius, and PN with nebular masses over one solar are observed.

  15. Version 2000 of the Catalogue of Galactic Planetary Nebulae

    Science.gov (United States)

    Kohoutek, L.

    2001-11-01

    The ``Catalogue of Galactic Planetary Nebulae (Version 2000)'' appears in Abhandlungen aus der Hamburger Sternwarte, Band XII in the year 2001. It is a continuation of CGPN(1967) and contains 1510 objects classified as galactic PNe up to the end of 1999. The lists of possible pre-PNe and possible post-PNe are also given. The catalogue is restricted only to the data belonging to the location and identification of the objects. It gives identification charts of PNe discovered since 1965 (published in the supplements to CGPN) and those charts of objects discovered earlier, which have wrong or uncertain identification. The question ``what is a planetary nebula'' is discussed and the typical values of PNe and of their central stars are summarized. Short statistics about the discoveries of PNe are given. The catalogue is also available in the Centre de Données, Strasbourg and at Hamburg Observatory via internet. The Catalogue 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/378/843

  16. The Integral Field View of the Orion Nebula

    Directory of Open Access Journals (Sweden)

    Adal Mesa-Delgado

    2014-01-01

    Full Text Available This paper reviews the major advances achieved in the Orion Nebula through the use of integral field spectroscopy (IFS. Since the early work of Vasconcelos and collaborators in 2005, this technique has facilitated the investigation of global properties of the nebula and its morphology, providing new clues to better constrain its 3D structure. IFS has led to the discovery of shock-heated zones at the leading working surfaces of prominent Herbig-Haro objects as well as the first attempt to determine the chemical composition of Orion protoplanetary disks, also known as proplyds. The analysis of these morphologies using IFS has given us new insights into the abundance discrepancy problem, a long-standing and unresolved issue that casts doubt on the reliability of current methods used for the determination of metallicities in the universe from the analysis of H II regions. Results imply that high-density clumps and high-velocity flows may play an active role in the production of such discrepancies. Future investigations based on the large-scale IFS mosaic of Orion will be very valuable for exploring how the integrated effect of small-scale structures may have impact at larger scales in the framework of star-forming regions.

  17. GRAVITATIONAL COLLAPSE AND FILAMENT FORMATION: COMPARISON WITH THE PIPE NEBULA

    International Nuclear Information System (INIS)

    Heitsch, Fabian; Ballesteros-Paredes, Javier; Hartmann, Lee

    2009-01-01

    Recent models of molecular cloud formation and evolution suggest that such clouds are dynamic and generally exhibit gravitational collapse. We present a simple analytic model of global collapse onto a filament and compare this with our numerical simulations of the flow-driven formation of an isolated molecular cloud to illustrate the supersonic motions and infall ram pressures expected in models of gravity-driven cloud evolution. We compare our results with observations of the Pipe Nebula, an especially suitable object for our purposes as its low star formation activity implies insignificant perturbations from stellar feedback. We show that our collapsing cloud model can explain the magnitude of the velocity dispersions seen in the 13 CO filamentary structure by Onishi et al. and the ram pressures required by Lada et al. to confine the lower-mass cores in the Pipe Nebula. We further conjecture that higher-resolution simulations will show small velocity dispersions in the densest core gas, as observed, but which are infall motions and not supporting turbulence. Our results point out the inevitability of ram pressures as boundary conditions for molecular cloud filaments, and the possibility that especially lower-mass cores still can be accreting mass at significant rates, as suggested by observations.

  18. IRAS surface brightness maps of reflection nebulae in the Pleiades

    Science.gov (United States)

    Castelaz, Michael W.; Werner, M. W.; Sellgren, K.

    1987-01-01

    Surface brightness maps at 12, 25, 60, and 100 microns were made of a 2.5 deg x 2.5 deg area of the reflection nebulae in the Pleiades by coadding IRAS scans of this region. Emission is seen surrounding 17 Tau, 20 Tau, 23 Tau, and 25 Tau in all four bands, coextensive with the visible reflection nebulosity, and extending as far as 30 arcminutes from the illuminating stars. The infrared energy distributions of the nebulae peak in the 100 micron band, but up to 40 percent of the total infrared power lies in the 12 and 25 micron bands. The brightness of the 12 and 25 micron emission and the absence of temperature gradients at these wavelengths are inconsistent with the predictions of equilibrium thermal emission models. The emission at these wavelengths appears to be the result of micron nonequilibrium emission from very small grains, or from molecules consisting of 10-100 carbon atoms, which have been excited by ultraviolet radiation from the illuminating stars.

  19. Gigahertz-peaked spectra pulsars in Pulsar Wind Nebulae

    Science.gov (United States)

    Basu, R.; RoŻko, K.; Kijak, J.; Lewandowski, W.

    2018-04-01

    We have carried out a detailed study of the spectral nature of six pulsars surrounded by pulsar wind nebulae (PWNe). The pulsar flux density was estimated using the interferometric imaging technique of the Giant Metrewave Radio Telescope at three frequencies 325, 610, and 1280 MHz. The spectra showed a turnover around gigahertz frequency in four out of six pulsars. It has been suggested that the gigahertz-peaked spectrum (GPS) in pulsars arises due to thermal absorption of the pulsar emission in surrounding medium like PWNe, H II regions, supernova remnants, etc. The relatively high incidence of GPS behaviour in pulsars surrounded by PWNe imparts further credence to this view. The pulsar J1747-2958 associated with the well-known Mouse nebula was also observed in our sample and exhibited GPS behaviour. The pulsar was detected as a point source in the high-resolution images. However, the pulsed emission was not seen in the phased-array mode. It is possible that the pulsed emission was affected by extreme scattering causing considerable smearing of the emission at low radio frequencies. The GPS spectra were modelled using the thermal free-free absorption and the estimated absorber properties were largely consistent with PWNe. The spatial resolution of the images made it unlikely that the point source associated with J1747-2958 was the compact head of the PWNe, but the synchrotron self-absorption seen in such sources was a better fit to the estimated spectral shape.

  20. Two different sources of water for the early solar nebula.

    Science.gov (United States)

    Kupper, Stefan; Tornow, Carmen; Gast, Philipp

    2012-06-01

    Water is essential for life. This is a trivial fact but has profound implications since the forming of life on the early Earth required water. The sources of water and the related amount of delivery depend not only on the conditions on the early Earth itself but also on the evolutionary history of the solar system. Thus we ask where and when water formed in the solar nebula-the precursor of the solar system. In this paper we explore the chemical mechanics for water formation and its expected abundance. This is achieved by studying the parental cloud core of the solar nebula and its gravitational collapse. We have identified two different sources of water for the region of Earth's accretion. The first being the sublimation of the icy mantles of dust grains formed in the parental cloud. The second source is located in the inner region of the collapsing cloud core - the so-called hot corino with a temperature of several hundred Kelvin. There, water is produced efficiently in the gas phase by reactions between neutral molecules. Additionally, we analyse the dependence of the production of water on the initial abundance ratio between carbon and oxygen.

  1. Nickel hydrogen bipolar battery electrode design

    Science.gov (United States)

    Puglisi, V. J.; Russell, P.; Verrier, D.; Hall, A.

    1985-01-01

    The preferred approach of the NASA development effort in nickel hydrogen battery design utilizes a bipolar plate stacking arrangement to obtain the required voltage-capacity configuration. In a bipolar stack, component designs must take into account not only the typical design considerations such as voltage, capacity and gas management, but also conductivity to the bipolar (i.e., intercell) plate. The nickel and hydrogen electrode development specifically relevant to bipolar cell operation is discussed. Nickel oxide electrodes, having variable type grids and in thicknesses up to .085 inch are being fabricated and characterized to provide a data base. A selection will be made based upon a system level tradeoff. Negative (hydrpogen) electrodes are being screened to select a high performance electrode which can function as a bipolar electrode. Present nickel hydrogen negative electrodes are not capable of conducting current through their cross-section. An electrode was tested which exhibits low charge and discharge polarization voltages and at the same time is conductive. Test data is presented.

  2. Comorbid medical illness in bipolar disorder.

    Science.gov (United States)

    Forty, Liz; Ulanova, Anna; Jones, Lisa; Jones, Ian; Gordon-Smith, Katherine; Fraser, Christine; Farmer, Anne; McGuffin, Peter; Lewis, Cathryn M; Hosang, Georgina M; Rivera, Margarita; Craddock, Nick

    2014-12-01

    Individuals with a mental health disorder appear to be at increased risk of medical illness. To examine rates of medical illnesses in patients with bipolar disorder (n = 1720) and to examine the clinical course of the bipolar illness according to lifetime medical illness burden. Participants recruited within the UK were asked about the lifetime occurrence of 20 medical illnesses, interviewed using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and diagnosed according to DSM-IV criteria. We found significantly increased rates of several medical illnesses in our bipolar sample. A high medical illness burden was associated with a history of anxiety disorder, rapid cycling mood episodes, suicide attempts and mood episodes with a typically acute onset. Bipolar disorder is associated with high rates of medical illness. This comorbidity needs to be taken into account by services in order to improve outcomes for patients with bipolar disorder and also in research investigating the aetiology of affective disorder where shared biological pathways may play a role. Royal College of Psychiatrists.

  3. Bipolar magnetic semiconductor in silicene nanoribbons

    International Nuclear Information System (INIS)

    Farghadan, Rouhollah

    2017-01-01

    Highlights: • A new electronic phase for silicene nanoribbon in the presence of electric and magnetic fields. • Bipolar magnetic semiconductor with controllable spin-flip and spin-conserved gaps in silicene. • Robust bipolar magnetic semiconductor features in a rough silicene. • Perfect and reversible spin polarization in silicene nanoribbon junctions. - Abstract: A theoretical study was presented on generation of spin polarization in silicene nanoribbons using the single-band tight-binding approximation and the non-equilibrium Green’s function formalism. We focused on the effect of electric and exchange magnetic fields on the spin-filter capabilities of zigzag-edge silicene nanoribbons in the presence of the intrinsic spin-orbit interaction. The results show that a robust bipolar magnetic semiconductor with controllable spin-flip and spin-conserved gaps can be obtained when exchange magnetic and electric field strengths are both larger than the intrinsic spin-orbit interaction. Therefore, zigzag silicene nanoribbons could act as bipolar and perfect spin filter devices with a large spin-polarized current and a reversible spin polarization in the vicinity of the Fermi energy. We also investigated the effect of edge roughness and found that the bipolar magnetic semiconductor features are robust against edge disorder in silicene nanoribbon junctions. These results may be useful in multifunctional spin devices based on silicene nanoribbons.

  4. [Drug Abuse Comorbidity in Bipolar Disorder].

    Science.gov (United States)

    Ortiz, Óscar Medina

    2012-06-01

    Drug use among patients with bipolar disorder is greater than the one observed in the general population; psychotic episodes are likely to occur after consumption. This has implications in the prevention, etiology, management, and treatment of the disease. Bipolar disorder pathology is likely to have positive response to pharmacological treatment. Therefore, identifying the strategies with better results to be applied in these patients is fundamental for psychiatrists and primary care physicians. Review literature in order to determine the prevalence and characteristics of drug abuse in patients with bipolar disorder and establish the pharmacological strategies that have produced better results. Literature review. A great variety of studies demonstrate the relationship between bipolar disorder and drug use disorder. These patients are hospitalized more frequently, have an earlier onset of the disease, and present a larger number of depressive episodes and suicide attempts which affect the course of the disease. The drug with better results in the treatment of these patients is Divalproate. Satisfactory results have been also obtained with other mood stabilizers such as carbamazepine, lamotrigine, and the antipsychotic aripiprazole. Substance abuse is present in a large number of patients with bipolar disorder. The Divalproate is the drug that has shown better results in the studies. Copyright © 2012 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

  5. Family History in Patients with Bipolar Disorder.

    Science.gov (United States)

    Özdemir, Osman; Coşkun, Salih; Aktan Mutlu, Elif; Özdemir, Pınar Güzel; Atli, Abdullah; Yilmaz, Ekrem; Keskin, Sıddık

    2016-09-01

    In this study, we aimed to better understand the genetic transmission of bipolar disorder by examining the family history of patients. Sixty-three patients with bipolar disorder and their families were included. The final sample comprised 156 bipolar patients and their family members. An inclusion criterion was the presence of bipolar disorder history in the family. The diagnosis of other family members was confirmed by analyzing their files, hospital records, and by calling them to the hospital. Sixty-five patients were women (41.6%) and 91 were men (58.3%) (ratio of men/women: 1.40). When analyzing the results in terms of the transition of disease from the mother's or father's side, similar results were obtained: 25 patients were from the mother's side and 25 patients were from the father's side in 63 cases. The results of our study support the fact that a significant relationship exists between the degree of kinship and the heritability of bipolar disorder and, furthermore, that the effect of the maternal and paternal sides is similar on the transmission of genetic susceptibility.

  6. Bipolar magnetic semiconductor in silicene nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Farghadan, Rouhollah, E-mail: rfarghadan@kashanu.ac.ir

    2017-08-01

    Highlights: • A new electronic phase for silicene nanoribbon in the presence of electric and magnetic fields. • Bipolar magnetic semiconductor with controllable spin-flip and spin-conserved gaps in silicene. • Robust bipolar magnetic semiconductor features in a rough silicene. • Perfect and reversible spin polarization in silicene nanoribbon junctions. - Abstract: A theoretical study was presented on generation of spin polarization in silicene nanoribbons using the single-band tight-binding approximation and the non-equilibrium Green’s function formalism. We focused on the effect of electric and exchange magnetic fields on the spin-filter capabilities of zigzag-edge silicene nanoribbons in the presence of the intrinsic spin-orbit interaction. The results show that a robust bipolar magnetic semiconductor with controllable spin-flip and spin-conserved gaps can be obtained when exchange magnetic and electric field strengths are both larger than the intrinsic spin-orbit interaction. Therefore, zigzag silicene nanoribbons could act as bipolar and perfect spin filter devices with a large spin-polarized current and a reversible spin polarization in the vicinity of the Fermi energy. We also investigated the effect of edge roughness and found that the bipolar magnetic semiconductor features are robust against edge disorder in silicene nanoribbon junctions. These results may be useful in multifunctional spin devices based on silicene nanoribbons.

  7. The Dutch Bipolar Offspring Study: 12-Year Follow-Up

    OpenAIRE

    Mesman, Esther; Nolen, Willem A.; Reichart, Catrien G.; Wals, Marjolein; Hillegers, Manon N. J.

    2013-01-01

    Objective: Offspring of bipolar parents have a genetically increased risk of developing mood disorders. In a longitudinal study, the authors followed a bipolar offspring cohort from adolescence into adulthood to determine the onset, prevalence, and early course of mood disorders and other psychopathology. Method: The Dutch bipolar offspring cohort is a fixed cohort initiated in 1997 (N=140; age range at baseline, 12-21 years). Bipolar offspring were psychiatrically evaluated at baseline and a...

  8. Rumination in bipolar disorder: evidence for an unquiet mind

    OpenAIRE

    Ghaznavi, Sharmin; Deckersbach, Thilo

    2012-01-01

    Abstract Depression in bipolar disorder has long been thought to be a state characterized by mental inactivity. However, recent research demonstrates that patients with bipolar disorder engage in rumination, a form of self-focused repetitive cognitive activity, in depressed as well as in manic states. While rumination has long been associated with depressed states in major depressive disorder, the finding that patients with bipolar disorder ruminate in manic states is unique to bipolar disord...

  9. Risk factors for suicide among children and youths with bipolar spectrum and early bipolar disorder.

    Science.gov (United States)

    Rajewska-Rager, Aleksandra; Sibilski, Piotr; Lepczyńska, Natalia

    2015-01-01

    In recent years much attention has been given to determine risk factors for suicide among adults with bipolar disorder. Such studies concerning children and youths, which would also take into account the specificity of the developmental age, are still too few. The ability to identify risk factors for children and youths with mood disorders, as well as the possibility to monitor them, is an essential element in preventing suicidal behaviours. Previous studies have clearly indicated that in the group of patients with an early onset of the bipolar disorder the occurrence of suicidal thoughts and intentions were significantly increased. Identifying the risk of suicide is hindered further by the complexity of the phenomenon, which is a compound interaction of various factors: biological, environmental, sociological, psychological and clinical. This is especially true with young adults suffering from mental illness and presenting a number of other psychopathological symptoms. The following paper introduces and reviews the results of current studies, which analysed the risk factors for suicide among children and youths with bipolar spectrum or already diagnosed with bipolar disorder. For this purpose we conducted the overview of recent years literature available in PubMed/MEDLINE database, including the following search criteria: early onset bipolar disorder, bipolar disorder in children and young people, the spectrum of bipolar disorder, and suicidal ideation, suicidal intent, suicide.

  10. The chemical composition of three planetary nebulae in the Magellanic clouds

    International Nuclear Information System (INIS)

    Dufour, R.J.; Killen, R.M.

    1977-01-01

    Emission-line intensities in the planetary nebulae Henize 67 in the Small Magellanic Cloud (SMC) and Henize 97 and 153 in the LMC along with the small SMC H II regions Henize 9, 61, and 81 were measured from photographic image-tube spectra taken with the 1.5 m telescope at Cerro Tololo. The relative abundances of H, He, N, O, Ne, S, and Ar in the nebulae were estimated and compared with the compositions of galactic planetary nebulae and previously studied H II regions in the Clouds. The results show that (1) the N/O ratios in the planetary nebulae are substantially higher than found in the H II regions of each Cloud; (2) He/H approx. = 0.18 in the SMC planetary nebula, but seems normal (approx.0.10) in the two LMC planetaries; and (3) the compositions of the three small SMC H II regions are similar to that of larger SMC H II regions studied previously. It is concluded that the N/H values in the shells of planetary nebulae may not depend on the metal content of the progenitor star as much as recent theoretical models suggest and that the N content of the gas in the Magellanic Clouds arises primarily from sources other than planetary nebulae

  11. Model planetary nebulae: the effect of shadowed filaments on low ionization potential ion radiation

    International Nuclear Information System (INIS)

    Katz, A.

    1977-01-01

    Previous homogeneous model planetary nebulae calculations No. 4 have yielded emission strengths for low ionization potential No. 4 ions which are considerably lower than those observed. Several attempts were to correct this problem by the inclusion of optically thin condensations, the use of energy flux distributions from stellar model calculations instead of blackbody spectrum stars, and the inclusion of dust in the nebulae. The effect that shadowed filaments have on the ionization and thermal structure of model nebulae and the resultant line strengths are considered. These radial filaments are shielded from the direct stellar ionizing radiation by optically thick condensations in the nebula. Theoretical observational evidence exists for the presence of condensations and filaments. Since the only source of ionizing photons in the shadowed filaments is due to diffuse photons produced by recombination, ions of lower ionization potential are expected to exist there in greater numbers than those found in the rest of the nebula. This leads to increased line strengths from these ions and increases their values to match the observational values. It is shown that these line strengths in the filaments increase by over one to two orders of magnitude relative to values found in homogeneous models. This results in an increase of approximately one order of magnitude for these lines when contributions from both components of the nebula are considered. The parameters that determine the exact value of the increase are the radial location of the filaments in the nebula and the fraction of the nebular volume occupied by the filaments

  12. A Self-Perpetuating Catalyst for the Production of Complex Organic Molecules in Protostellar Nebulae

    Science.gov (United States)

    Nuth, Joseph A.; Johnson, N. M.

    2010-01-01

    The formation of abundant carbonaceous material in meteorites is a long standing problem and an important factor in the debate on the potential for the origin of life in other stellar systems. Many mechanisms may contribute to the total organic content in protostellar nebulae, ranging from organics formed via ion-molecule and atom-molecule reactions in the cold dark clouds from which such nebulae collapse, to similar ion-molecule and atom-molecule reactions in the dark regions of the nebula far from the proto star, to gas phase reactions in sub-nebulae around growing giant planets and in the nebulae themselves. The Fischer-Tropsch-type (FTT) catalytic reduction of CO by hydrogen was once the preferred model for production of organic materials in the primitive solar nebula. The Haber-Bosch catalytic reduction of N2 by hydrogen was thought to produce the reduced nitrogen found in meteorites. However, the clean iron metal surfaces that catalyze these reactions are easily poisoned via reaction with any number of molecules, including the very same complex organics that they produce and both reactions work more efficiently in the hot regions of the nebula. We have demonstrated that many grain surfaces can catalyze both FTT and HB-type reactions, including amorphous iron and magnesium silicates, pure silica smokes as well as several minerals. Although none work as well as pure iron grains, and all produce a wide range of organic products rather than just pure methane, these materials are not truly catalysts.

  13. On Bipolar Valued Fuzzy k-Ideals in Hermirings

    International Nuclear Information System (INIS)

    Mahmood, T.; Ejaz, A.

    2015-01-01

    In this paper we discuss some results associated with bipolar valued fuzzy k -ideals of hermirings. We also define bipolar valued fuzzy k-intrinsic product and characterize k-hemiregular hermirings by using their bipolar valued fuzzy k -ideals. (author)

  14. Dose enhancement effects of X ray radiation in bipolar transistors

    International Nuclear Information System (INIS)

    Chen Panxun

    1997-01-01

    The author has presented behaviour degradation and dose enhancement effects of bipolar transistors in X ray irradiation environment. The relative dose enhancement factors of X ray radiation were measured in bipolar transistors by the experiment methods. The mechanism of bipolar device dose enhancement was investigated

  15. Family Functioning and the Course of Adolescent Bipolar Disorder

    Science.gov (United States)

    Sullivan, Aimee E.; Judd, Charles M.; Axelson, David A.; Miklowitz, David J.

    2012-01-01

    The symptoms of bipolar disorder affect and are affected by the functioning of family environments. Little is known, however, about the stability of family functioning among youth with bipolar disorder as they cycle in and out of mood episodes. This study examined family functioning and its relationship to symptoms of adolescent bipolar disorder,…

  16. Structure of the solar nebula, growth and decay of magnetic fields and effects of magnetic and turbulent viscosities on the nebula

    International Nuclear Information System (INIS)

    Hayashi, Chushiro

    1982-01-01

    First, distributions of surface densities of dust materials and gases in a preplanetary solar nebula, which give a good fit to the distribution of the planetary mass, are presented and the over-all structure of this nebula, which is in thermal and gravitational equilibrium, is studied. Second, in order to see magnetic effect on the structure, electric conductivity of a gas ionized by cosmic rays and radioactivities contained in dust grains is estimated for each region of the nebula and, then, the growth and decay of seed magnetic fields, which are due to differential rotation of the nebula and to the Joule dissipation, respectively, are calculated. The results indicate that, in regions of the terrestrial planets, magnetic fields decay much faster than they grow and magnetic effects can be ignored, except for the outermost layers of very low density. This is not the case for regions of Uranus and Neptune where magnetic fields can be amplified to considerable extents. Third, the transport of angular momentum due to magnetic and mechanical turbulent viscosities and the resultant redistribution of surface density in the nebula are investigated. The results show that the density redistribution occurs, in general, in a direction to attain a distribution of surface density which has nearly the same ν-dependence as that obtained from the present distribution of the planetary mass. This redistribution seems to be possible if it occurs at a formation stage of the nebula where the presence of large viscosities is expected. Finally, a comment is given on the initial condition of a collapsing interstellar cloud from which the solar nebula is formed at the end of the collapse. (author)

  17. Ion transport Modeling in a Bipolar Membrane

    International Nuclear Information System (INIS)

    Kim, Jung Soo; Park, Kwang Heon; Kim, Kwang Wook

    2010-01-01

    The COL(Carbonate-based Oxidative Leaching) process is an environmentally-friendly technique for collecting only uranium from spent fuel with oxidation leaching/ precipitation of carbonate solution. The bipolar membrane used for the electrolyte circulation of the salt used in the COL process is a special form of ion exchange membrane which combines CEM(cation exchange membrane) and AEM(anion exchange membrane). After arranging positive ion exchange layer toward negative terminal and positive ion exchange layer toward positive terminal, then supply electricity, water molecules are decomposed into protons and hydroxyl ions by a strong electric field in the transition region inside bipolar membrane.1) In this study, a theoretical approach to increase the efficiency of Na + and NO3 - ion collecting device using bipolar membrane was taken and simulating using the COMSOL program was tried. The details of results are also discussed

  18. Neuronal migration, apoptosis and bipolar disorder.

    Science.gov (United States)

    Uribe, Ezequiel; Wix, Richard

    2012-01-01

    Bipolar disorder, like the majority of psychiatric disorders, is considered a neurodevelopment disease of neurodevelopment. There is an increased rate of neuronal birth and death during this development period. In the particular case of the processes that determine neuronal death, it is known that those neurons that establish connections have to be removed from the central nervous system. There is a deficit of GABAergic interneurons in the cerebral cortex in bipolar disorder, accompanied by overexpression of proapoptic genes. There is also an alteration in the expression of molecules that mediate in the migration of these neurons and their inclusion in functional synapsis during the foetal stage. The role of these molecules in the neuronal death pathways by apoptosis will be reviewed here in an attempt to establish biological hypotheses of the genesis of bipolar disorder. Copyright © 2011 SEP y SEPB. Published by Elsevier Espana. All rights reserved.

  19. Concurrent hypokalemic periodic paralysis and bipolar disorder

    Directory of Open Access Journals (Sweden)

    Chia-Lin Lin

    2015-01-01

    Full Text Available Primary periodic paralysis is a rare autosomal dominant disorder of ion-channel dysfunction, manifested by episodic flaccid paresis secondary to abnormal sarcolemma excitability. Membrane destabilization involving Na, K-ATPase has been hypothesized to be a biological etiology of the bipolar disorder (BD and the mechanisms underlying lithium therapy have been linked to it. To date, there has been only one reported case of BD comorbid with periodic paralysis. Herein, we reported another case of concurrent bipolar mania and hypokalemic periodic paralysis (HPP, one special form of periodic paralysis. Consistent with the previous case, our patient responded well to lithium treatment for both bipolar mania and HPP. This might provide some support to the hypothesis that the therapeutic effects of lithium in both BD and HPP could be due to the correction of the underlying common pathophysiology.

  20. Fenomenologia do tempo vivido no transtorno bipolar

    Directory of Open Access Journals (Sweden)

    Virginia Moreira

    Full Text Available Com base na tradição da psicopatologia fenomenológica, este artigo se propõe a contribuir para a compreensão do mundo vivido do paciente bipolar, marcado por uma forte alteração do tempo vivido. Realizamos uma descrição deste tempo vivido significado de forma diferente nas oscilações de humor chamadas de fase maníaca e fase melancólica. Pensado a partir da temporalidade, na fase melancólica, o bipolar parece parar no tempo, não se lança em um devir. Na fase maníaca, o sujeito vive demasiadamente um agora como se tivesse explodido sua biografia. Concluímos que estas fases, ou dois pólos opostos no funcionamento temporal patológico do sofrimento bipolar, constituem fundamentalmente um mesmo mundo vivido.

  1. Genetic structure of personality factors and bipolar disorder in families segregating bipolar disorder.

    Science.gov (United States)

    Hare, Elizabeth; Contreras, Javier; Raventos, Henriette; Flores, Deborah; Jerez, Alvaro; Nicolini, Humberto; Ontiveros, Alfonso; Almasy, Laura; Escamilla, Michael

    2012-02-01

    Bipolar disorder (BPD) has been associated with variations in personality dimensions, but the nature of this relationship has been unclear. In this study, the heritabilities of BPD and the Big Five personality factors and the genetic correlations between BPD and personality factors are reported. The participants in this study were 1073 individuals from 172 families of Mexican or Central American ancestry. Heritabilities and genetic correlations were calculated under a polygenic model using the maximum-likelihood method of obtaining variance components implemented in the SOLAR software package. Heritabilities of 0.49, 0.43, and 0.43 were found for the narrowest phenotype (schizoaffective bipolar and bipolar I), the intermediate phenotype (schizoaffective bipolar, bipolar I, and bipolar II), and the broadest phenotype (schizoaffective bipolar, bipolar I, bipolar II, and recurrent depression), respectively. For the Big Five personality factors, heritabilities were 0.25 for agreeableness, 0.24 for conscientiousness, 0.24 for extraversion, 0.23 for neuroticism, and 0.32 for openness to experience. For the narrowest phenotype, a significant negative correlation (-0.32) with extraversion was found. For the broadest phenotype, negative correlations were found for agreeableness (-0.35), conscientiousness (-0.39), and extraversion (-0.44). A positive correlation (0.37) was found with neuroticism. It is not possible to determine whether aspects of personality are factors in the development of bipolar disorder or vice versa. The short form of the NEO does not provide the ability to examine in detail which facets of extraversion are most closely related to bipolar disorder or to compare our results with studies that have used the long version of the scale. This study establishes a partial genetic basis for the Big Five personality factors in this set of families, while the environmental variances demonstrate that non-genetic factors are also important in their influence on

  2. Nanosecond bipolar pulse generators for bioelectrics.

    Science.gov (United States)

    Xiao, Shu; Zhou, Chunrong; Yang, Enbo; Rajulapati, Sambasiva R

    2018-04-26

    Biological effects caused by a nanosecond pulse, such as cell membrane permeabilization, peripheral nerve excitation and cell blebbing, can be reduced or cancelled by applying another pulse of reversed polarity. Depending on the degree of cancellation, the pulse interval of these two pulses can be as long as dozens of microseconds. The cancellation effect diminishes as the pulse duration increases. To study the cancellation effect and potentially utilize it in electrotherapy, nanosecond bipolar pulse generators must be made available. An overview of the generators is given in this paper. A pulse forming line (PFL) that is matched at one end and shorted at the other end allows a bipolar pulse to be produced, but no delay can be inserted between the phases. Another generator employs a combination of a resistor, an inductor and a capacitor to form an RLC resonant circuit so that a bipolar pulse with a decaying magnitude can be generated. A third generator is a converter, which converts an existing unipolar pulse to a bipolar pulse. This is done by inserting an inductor in a transmission line. The first phase of the bipolar pulse is provided by the unipolar pulse's rising phase. The second phase is formed during the fall time of the unipolar pulse, when the inductor, which was previously charged during the flat part of the unipolar pulse, discharges its current to the load. The fourth type of generator uses multiple MOSFET switches stacked to turn on a pre-charged, bipolar RC network. This approach is the most flexible in that it can generate multiphasic pulses that have different amplitudes, delays, and durations. However, it may not be suitable for producing short nanosecond pulses (<100 ns), whereas the PFL approach and the RLC approach with gas switches are used for this range. Thus, each generator has its own advantages and applicable range. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Planetary nebulae: understanding the physical and chemical evolution of dying stars.

    Science.gov (United States)

    Weinberger, R; Kerber, F

    1997-05-30

    Planetary nebulae are one of the few classes of celestial objects that are active in every part of the electromagnetic spectrum. These fluorescing and often dusty expanding gaseous envelopes were recently found to be quite complex in their dynamics and morphology, but refined theoretical models can account for these discoveries. Great progress was also made in understanding the mechanisms that shape the nebulae and the spectra of their central stars. In addition, applications for planetary nebulae have been worked out; for example, they have been used as standard candles for long-range distances and as tracers of the enigmatic dark matter.

  4. The colorimetry of the nebulae NGC 6914b and Parsamian 22

    International Nuclear Information System (INIS)

    Khachikyan, Eh.E.; Ehjnatyan, D.A.

    1975-01-01

    Given in the paper are the results of colorimetry of two diffuse nebulae: NGC 6914b and Parsamian 22. Use was made of pictures obtained on the one-meter Schmidt telescope of the Byurakan Observatory. The surface brightness of certain regions of the nebulae and their colors (U-B) and (B-V) have been determined. Although these nebulae are seen in the same sky region, they differ sharply in color: NGC 6914b is intensely blue, while Parsamian 22 is intensely red

  5. Central Stars of Mid-Infrared Nebulae Discovered with Spitzer and WISE

    Science.gov (United States)

    Gvaramadze, V. V.; Kniazev, A. Y.

    2017-02-01

    Searches for compact mid-IR nebulae with the Spitzer Space Telescope and the Wide-field Infrared Survey Explorer (WISE), accompanied by spectroscopic observations of central stars of these nebulae led to the discovery of many dozens of massive stars at different evolutionary stages, of which the most numerous are candidate luminous blue variables (LBVs). In this paper, we give a census of candidate and confirmed Galactic LBVs revealed with Spitzer and WISE, and present some new results of spectroscopic observations of central stars of mid-IR nebulae.

  6. Three times more days depressed than manic or hypomanic in both bipolar I and bipolar II disorder

    NARCIS (Netherlands)

    Kupka, Ralph W.; Altshuler, Lori L.; Nolen, Willem A.; Suppes, Trisha; Luckenbaugh, David A.; Leverich, Gabriele S.; Frye, Mark A.; Keck, Paul E.; McElroy, Susan L.; Grunze, Heinz; Post, Robert M.

    Objectives: To assess the proportion of time spent in mania, depression and euthymia in a large cohort of bipolar subjects studied longitudinally, and to investigate depression/mania ratios in patients with bipolar I versus bipolar II disorder. Methods: Clinician-adjusted self-ratings of mood were

  7. Alcoholism and anxiety in bipolar illness : Differential lifetime anxiety comorbidity in bipolar I women with and without alcoholism

    NARCIS (Netherlands)

    Levander, Eric; Frye, Mark A.; McElroy, Susan; Suppes, Trisha; Grunze, Heinz; Nolen, Willem A.; Kupka, Ralph; Keck, Paul E.; Leverich, Gabriele S.; Altshuler, Lori L.; Hwang, Sun; Mintz, Jim; Post, Robert M.

    Introduction: This study was undertaken to evaluate the prevalence rate of anxiety comorbidity in bipolar subjects with and without alcohol use disorders (AUD). Methods: Bipolar men and women who entered the Stanley Foundation Bipolar Network (SFBN) underwent a Structured Clinical Interview for

  8. Prediction of transition from common adolescent bipolar experiences to bipolar disorder: 10-year study.

    Science.gov (United States)

    Tijssen, Marijn J A; van Os, Jim; Wittchen, Hans-Ulrich; Lieb, Roselind; Beesdo, Katja; Mengelers, Ron; Wichers, Marieke

    2010-02-01

    Although (hypo)manic symptoms are common in adolescence, transition to adult bipolar disorder is infrequent. To examine whether the risk of transition to bipolar disorder is conditional on the extent of persistence of subthreshold affective phenotypes. In a 10-year prospective community cohort study of 3021 adolescents and young adults, the association between persistence of affective symptoms over 3 years and the 10-year clinical outcomes of incident DSM-IV (hypo)manic episodes and incident use of mental healthcare was assessed. Transition to clinical outcome was associated with persistence of symptoms in a dose-dependent manner. Around 30-40% of clinical outcomes could be traced to prior persistence of affective symptoms. In a substantial proportion of individuals, onset of clinical bipolar disorder may be seen as the poor outcome of a developmentally common and usually transitory non-clinical bipolar phenotype.

  9. The Coldest Place in the Universe: Probing the Ultra-cold Outflow and Dusty Disk in the Boomerang Nebula

    Science.gov (United States)

    Sahai, R.; Vlemmings, W. H. T.; Nyman, L.-Å.

    2017-06-01

    Our Cycle 0 ALMA observations confirmed that the Boomerang Nebula is the coldest known object in the universe, with a massive high-speed outflow that has cooled significantly below the cosmic background temperature. Our new CO 1-0 data reveal heretofore unseen distant regions of this ultra-cold outflow, out to ≳120,000 au. We find that in the ultra-cold outflow, the mass-loss rate (\\dot{M}) increases with radius, similar to its expansion velocity (V)—taking V\\propto r, we find \\dot{M}\\propto {r}0.9{--2.2}. The mass in the ultra-cold outflow is ≳ 3.3 M ⊙, and the Boomerang’s main-sequence progenitor mass is ≳ 4 M ⊙. Our high angular resolution (˜ 0\\buildrel{\\prime\\prime}\\over{.} 3) CO J = 3-2 map shows the inner bipolar nebula’s precise, highly collimated shape, and a dense central waist of size (FWHM) ˜1740 au × 275 au. The molecular gas and the dust as seen in scattered light via optical Hubble Space Telescope imaging show a detailed correspondence. The waist shows a compact core in thermal dust emission at 0.87-3.3 mm, which harbors (4{--}7)× {10}-4 M ⊙ of very large (˜millimeter-to-centimeter sized), cold (˜ 20{--}30 K) grains. The central waist (assuming its outer regions to be expanding) and fast bipolar outflow have expansion ages of ≲ 1925 {years} and ≤slant 1050 {years}: the “jet-lag” (I.e., torus age minus the fast-outflow age) in the Boomerang supports models in which the primary star interacts directly with a binary companion. We argue that this interaction resulted in a common-envelope configuration, while the Boomerang’s primary was an RGB or early-AGB star, with the companion finally merging into the primary’s core, and ejecting the primary’s envelope that now forms the ultra-cold outflow.

  10. Ionization structure of planetary nebulae. 4. NGC 6853

    International Nuclear Information System (INIS)

    Barker, T.

    1983-01-01

    Spectrophotometric observations of emission line intensities were made in seven positions in the planetary nebula NGC 6853. For five of the positions, coverage is across the entire spectral range 1400A to 9600A. Standard equations used to correct for the existence of elements in other than the optically-observable ionization stages give results over a wide range of ionization that are generally consistent and in agreement with abundances calculated using ultraviolet lines. As in the previous studies in this series, the lambda 4267 CII line implies a c(2+) abundance that is higher than that determined from UV lines. Although this effect is much smaller than in NGC 6720 and NGC 7009, it is again largest nearest the central star, giving more evidence that the excitation mechanism for the lambda 4267 line is not understood

  11. An earlier explosion date for the Crab Nebula supernova

    Science.gov (United States)

    Abt, Helmut A.; Fountain, John W.

    2018-04-01

    The Chinese first reported the Crab Nebula supernova on 1054 July 5. Ecclesiastical documents from the near east reported it in April and May of 1054. More than 33 petroglyphs made by Native Americans in the US and Mexico are consistent with sightings both before and after conjunction with the Sun on 1054 May 27. We found a petroglyph showing the new star close to Venus and the Moon, which occurred on 1054 April 12 and April 13, respectively. Collins et al., using the four historical dates, derived a light curve that is like that of a Type Ia supernova. The only remaining problem with this identification is that this supernova was near maximum light for 85 d, which is unlike the behavior of any known supernova.

  12. Volatile inventories in clathrate hydrates formed in the primordial nebula.

    Science.gov (United States)

    Mousis, Olivier; Lunine, Jonathan I; Picaud, Sylvain; Cordier, Daniel

    2010-01-01

    The examination of ambient thermodynamic conditions suggests that clathrate hydrates could exist in the Martian permafrost, on the surface and in the interior of Titan, as well as in other icy satellites. Clathrate hydrates are probably formed in a significant fraction of planetesimals in the solar system. Thus, these crystalline solids may have been accreted in comets, in the forming giant planets and in their surrounding satellite systems. In this work, we use a statistical thermodynamic model to investigate the composition of clathrate hydrates that may have formed in the primordial nebula. In our approach, we consider the formation sequence of the different ices occurring during the cooling of the nebula, a reasonable idealization of the process by which volatiles are trapped in planetesimals. We then determine the fractional occupancies of guests in each clathrate hydrate formed at a given temperature. The major ingredient of our model is the description of the guest-clathrate hydrate interaction by a spherically averaged Kihara potential with a nominal set of parameters, most of which are fitted to experimental equilibrium data. Our model allows us to find that Kr, Ar and N2 can be efficiently encaged in clathrate hydrates formed at temperatures higher than approximately 48.5 K in the primitive nebula, instead of forming pure condensates below 30 K. However, we find at the same time that the determination of the relative abundances of guest species incorporated in these clathrate hydrates strongly depends on the choice of the parameters of the Kihara potential and also on the adopted size of cages. Indeed, by testing different potential parameters, we have noted that even minor dispersions between the different existing sets can lead to non-negligible variations in the determination of the volatiles trapped in clathrate hydrates formed in the primordial nebula. However, these variations are not found to be strong enough to reverse the relative abundances

  13. Two-dimensional spectrophotometry of planetary nebulae by CCD imaging

    International Nuclear Information System (INIS)

    Jacoby, G.H.; Africano, J.L.; Quigley, R.J.; Western Washington Univ., Bellingham, WA)

    1987-01-01

    The spatial distribution of the electron temperature and density and the ionic abundances of O(+), O(2+), N(+), and S(+) have been derived from CCD images of the planetary nebulae NGC 40 and NGC 6826 taken in the important emission lines of forbidden O II, forbidden O III, H-beta, forbidden N II, and forbidden S II. The steps required in the derivation of the absolute fluxes, line, ratios, and ionic abundances are outlined and then discussed in greater detail. The results show that the CCD imaging technique for two-dimensional spectrophotometry can effectively compete with classical spectrophotometry, providing the added benefits of complete spatial coverage at seeing-disk spatial resolution. The multiplexing in the spatial dimension, however, results in a loss of spectral information, since only one emission line is observed at any one time. 37 references

  14. The ultraviolet extinction properties of the 30 Dor Nebula

    Science.gov (United States)

    De Marchi, Guido; Panagia, Nino

    2018-01-01

    Recent investigation of the extinction law in 30 Dor and the Tarantula Nebula, at optical and near infrared wavelengths, has revealed a ratio of total to selective extinction RV=AV/E(B-V) of about 4.5. This indicates a larger proportion of large grains than in the Galactic diffuse interstellar medium. Possible origins include coalescence of small grains, grain growth, selective destruction of small grains, and fresh injection of large grains. From a study of the ultraviolet extinction properties of three Wolf-Rayet stars in 30 Dor (R 139, R 140, R 145), observed with the International Ultraviolet Explorer, we show that the excess of large grains does not come at the expense of small grains, which are still present. Fresh injection of large grains by supernova explosions appears to be the dominant mechanism.

  15. Discovery of new planetary nebulae in the Small Magellanic Cloud

    International Nuclear Information System (INIS)

    Drašković, D.; Reid, W. A.; Parker, Q. A.; Stupar, M.

    2016-01-01

    We present six new planetary nebulae (PNe) discovered in the Small Magellanic Cloud (SMC) from deep UK Schmidt telescope (UKST) narrow band Ha and broad-band short- red “SR” continuum images and confirmed spectroscopically. These 6 preliminary discoveries provide a 6% increase to the previously known SMC PN population of ∼⃒100. Once spectroscopic follow-up of all our newly identified candidates is complete, we expect to increase the total number of known SMC PNe by up to 50%. This will permit a significant improvement to determination of the SMC PN luminosity function (PNLF) and enable further insights into the chemical evolution and kinematics of the SMC PN population. (paper)

  16. The Σ − D relation for planetary nebulae: Preliminary analysis

    Directory of Open Access Journals (Sweden)

    Urošević D.

    2007-01-01

    Full Text Available An analysis of the relation between radio surface brightness and diameter, so-called Σ − D relation, for planetary nebulae (PNe is presented: i the theoretical Σ − D relation for the evolution of bremsstrahlung surface brightness is derived; ii contrary to the results obtained earlier for the Galactic supernova remnant (SNR samples, our results show that the updated sample of Galactic PNe does not severely suffer from volume selection effect - Malmquist bias (same as for the extragalactic SNR samples and; iii we conclude that the empirical S − D relation for PNe derived in this paper is not useful for valid determination of distances for all observed PNe with unknown distances. .

  17. The radial velocities of planetary nebulae in NGC 3379

    Science.gov (United States)

    Ciardullo, Robin; Jacoby, George H.; Dejonghe, Herwig B.

    1993-09-01

    We present the results of a radial velocity survey of planetary nebulae (PNs) in the normal elliptical galaxy NGC 3379 performed with the Kitt Peak 4 m telescope and the NESSIE multifiber spectrograph. In two half-nights, we measured 29 PNs with projected galactocentric distances between 0.4 and 3.8 effective radii with an observational uncertainty of about 7 km/s. These data extend three times farther into the halo than any previous absorption-line velocity study. The velocity dispersion and photometric profile of the galaxy agrees extremely well with that expected from a constant mass-to-light ratio, isotropic orbit Jaffe model with M/L(B) about 7; the best-fitting anisotropic models from a quadratic programming algorithm also give M/L(B) about 7. The data are consistent with models that contain no dark matter within 3.5 effective radii of the galaxy's nucleus.

  18. Herbig-Haro objects and T Tauri nebulae

    International Nuclear Information System (INIS)

    Boehm, K.H.

    1975-01-01

    The empirical information about Herbig-Haro objects and T Tauri nebulae is summarized. We emphasize especially the importance of the spectroscopic and spectrophotometric data. Relative and (preliminary) absolute emission line fluxes are presented and discussed. We consider the radial velocity data and the detection of a faint blue continuum in Herbig-Haro objects as important from a theoretical point of view. The direct interpretation of the emission line spectra is simple and leads to values of the electron temperature, electron density, density inhomogeneities, filling factors, degree of ionization and chemical abundances. The relevant procedures are discussed in some detail. The possible role of the Herbig-Haro objects in the early phases of stellar evolution is discussed. (orig./BJ) [de

  19. BIPOLAR DISORDER AND METABOLIC SYNDROME: COMORBIDITY OR SIDE EFFECTS OF TREATMENT OF BIPOLAR DISORDER

    OpenAIRE

    Babić, Dragan; Maslov, Boris; Nikolić, Katica; Martinac, Marko; Uzun, Suzana; Kozumplik, Oliver

    2010-01-01

    Objective: There is evidence that people with mental disorders are more likely to suffer from metabolic syndrome. In the last decades there has been an increase in interest for researching metabolic syndrome in psychiatric patients and plenty of evidence about their association. However, investigations on the prevalence of metabolic syndrome in patients with bipolar disorder are still surprisingly rare. The aim of this paper is to analyze comorbidity of bipolar disorder and metabolic syndrome...

  20. Synthesis of Organics in the Early Solar Nebula

    Science.gov (United States)

    Johnson, Natasha M.; Manning, S.; Nuth, J. A., III

    2007-10-01

    It is unknown what process or processes made the organics that are found or detected in extraterrestrial materials. One process that forms organics are Fischer-Tropsch type (FTT) reactions. Fischer-Tropsch type synthesis produces complex hydrocarbons by hydrogenating carbon monoxide via surface mediated reactions. The products of these reactions have been well-studied using `natural’ catalysts [1] and calculations of the efficiency of FTT synthesis in the Solar Nebula suggest that these types of reactions could make significant contributions to material near three AU [2]. We use FTT synthesis to coat Fe-silicate amorphous grains with organic material to simulate the chemistry in the early Solar Nebula. These coatings are composed of macromolecular organic phases [3]. Previous work also showed that as the grains became coated, Haber-Bosch type reactions took place resulting in nitrogen-bearing organics [4]. Our experiments consist of circulating CO, N2, and H2 gas through Fe- amorphous silicate grains that are maintained at a specific temperature in a closed system. The gases are passed through an FTIR spectrometer and are measured to monitor the reaction progress. Samples are analyzed using FTIR, and GCMS (including pyrolysis) and extraction techniques are used to analyze the organic coatings. These experiments show that these types of reactions are an effective means to produce complex hydrocarbons. We present the analysis of the produced organics (solid and gas phase) and the change in the production rate of several compounds as the grains become coated. Organics generated by this technique could represent the carbonaceous material incorporated in comets and meteorites. References: [1] Hayatsu and Anders 1981. Topics in Current Chemistry 99:1-37. [2] Kress and Tielens 2001. MAPS 36:75-91. [3] Johnson et al. 2004. #1876. 35th LPSC. [4] Hill and Nuth 2003. Astrobiology 3:291-304. This work was supported by a grant from NASA.