WorldWideScience

Sample records for central massive objects

  1. Correlations Between Central Massive Objects And Their Host Galaxies: From Bulgeless Spirals to Ellipticals

    OpenAIRE

    Li, Yuexing; Haiman, Zoltán; Mac Low, Mordecai-Mark

    2006-01-01

    Recent observations by Ferrarese et al. (2006) and Wehner et al. (2006) reveal that a majority of galaxies contain a central massive object (CMO), either a supermassive black hole (SMBH) or a compact stellar nucleus, regardless of the galaxy mass or morphological type, and that there is a tight relation between the masses of CMOs and those of the host galaxies. Several recent studies show that feedback from black holes can successfully explain the $\\msigma$ correlation in massive elliptical g...

  2. SED Modeling of 20 Massive Young Stellar Objects

    Science.gov (United States)

    Tanti, Kamal Kumar

    In this paper, we present the spectral energy distributions (SEDs) modeling of twenty massive young stellar objects (MYSOs) and subsequently estimated different physical and structural/geometrical parameters for each of the twenty central YSO outflow candidates, along with their associated circumstellar disks and infalling envelopes. The SEDs for each of the MYSOs been reconstructed by using 2MASS, MSX, IRAS, IRAC & MIPS, SCUBA, WISE, SPIRE and IRAM data, with the help of a SED Fitting Tool, that uses a grid of 2D radiative transfer models. Using the detailed analysis of SEDs and subsequent estimation of physical and geometrical parameters for the central YSO sources along with its circumstellar disks and envelopes, the cumulative distribution of the stellar, disk and envelope parameters can be analyzed. This leads to a better understanding of massive star formation processes in their respective star forming regions in different molecular clouds.

  3. Near-infrared spectroscopic observations of massive young stellar object candidates in the central molecular zone

    Science.gov (United States)

    Nandakumar, G.; Schultheis, M.; Feldmeier-Krause, A.; Schödel, R.; Neumayer, N.; Matteucci, F.; Ryde, N.; Rojas-Arriagada, A.; Tej, A.

    2018-01-01

    Context. The central molecular zone (CMZ) is a 200 pc region around the Galactic centre. The study of star formation in the central part of the Milky Way is of great interest as it provides a template for the closest galactic nuclei. Aims: We present a spectroscopic follow-up of photometrically selected young stellar object (YSO) candidates in the CMZ of the Galactic centre. Our goal is to quantify the contamination of this YSO sample by reddened giant stars with circumstellar envelopes and to determine the star formation rate (SFR) in the CMZ. Methods: We obtained KMOS low-resolution near-infrared spectra (R 4000) between 2.0 and 2.5 μm of sources, many of which have been previously identified by mid-infrared photometric criteria as massive YSOs in the Galactic centre. Our final sample consists of 91 stars with good signal-to-noise ratio. We separated YSOs from cool late-type stars based on spectral features of CO and Brγ at 2.3 μm and 2.16 μm, respectively. We made use of spectral energy distribution (SED) model fits to the observed photometric data points from 1.25 to 24 μm to estimate approximate masses for the YSOs. Results: Using the spectroscopically identified YSOs in our sample, we confirm that existing colour-colour diagrams and colour-magnitude diagrams are unable to efficiently separate YSOs and cool late-type stars. In addition, we define a new colour-colour criterion that separates YSOs from cool late-type stars in the H-KS vs. H -[8.0] diagram. We use this new criterion to identify YSO candidates in the |l| rate than predicted by various star forming models. Based on observations collected at the European Southern Observatory, Chile, programme number 097.C-0208(A).

  4. On The Detachment of Massive Trans-Neptunian Objects

    Science.gov (United States)

    Fleisig, Jacob; Madigan, Ann-Marie; Zderic, Alexander

    2018-06-01

    Our Solar System contains a large population of icy bodies stretching well beyond the orbit of Neptune. These objects, known collectively as the Scattered Disk, are remnants from the early formation of the Solar System that were scattered outward from their birth location by Neptune. But not all fit the bill.Sedna, one particularly massive Trans-Neptunian Object (TNO), does not conform to the scattering pattern. Its orbital eccentricity (e) is much lower than expected for a scattered object. This means its perihelion distance (proportional to 1-e) is much larger than the orbit of Neptune, or that it is “detached” from the main Solar System. Many more TNOs share similarities with Sedna. These observations suggest that there is a large population of detached TNOs that have a dynamical history different than that of the objects scattered by Neptune.The physical mechanism by which these massive minor planets become detached is currently unknown. However, we have discovered a phenomenon, driven by differential precession between TNOs of different masses and mutual secular gravitational torques, that naturally detach massive minor planets. This mechanism could have notable consequences for the outer Solar System and may shed some light on the origin of the detached population of minor planets near the Scattered Disk.

  5. Massive Young Stellar Objects in the Galactic Center. 1; Spectroscopic Identification from Spitzer/IRS Observations

    Science.gov (United States)

    An, Deokkeun; Ramirez, Solange V.; Sellgren, Kris; Arendt, Richard G.; Boogert, A. C. Adwin; Robitaille, Thomas P.; Schultheis, Mathias; Cotera, Angela S.; Smith, Howard A.; Stolovy, Susan R.

    2011-01-01

    We present results from our spectroscopic study, using the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope, designed to identify massive young stellar objects (YSOs) in the Galactic Center (GC). Our sample of 107 YSO candidates was selected based on IRAC colors from the high spatial resolution, high sensitivity Spitzer/IRAC images in the Central Molecular Zone (CMZ), which spans the central approximately 300 pc region of the Milky Way Galaxy. We obtained IRS spectra over 5 micron to 35 micron using both high- and low-resolution IRS modules. We spectroscopically identify massive YSOs by the presence of a 15.4 micron shoulder on the absorption profile of 15 micron CO2 ice, suggestive of CO2 ice mixed with CH30H ice on grains. This 15.4 micron shoulder is clearly observed in 16 sources and possibly observed in an additional 19 sources. We show that 9 massive YSOs also reveal molecular gas-phase absorption from C02, C2H2, and/or HCN, which traces warm and dense gas in YSOs. Our results provide the first spectroscopic census of the massive YSO population in the GC. We fit YSO models to the observed spectral energy distributions and find YSO masses of 8 - 23 solar Mass, which generally agree with the masses derived from observed radio continuum emission. We find that about 50% of photometrically identified YSOs are confirmed with our spectroscopic study. This implies a preliminary star formation rate of approximately 0.07 solar mass/yr at the GC.

  6. Variability of Massive Young Stellar Objects in Cygnus-X

    Science.gov (United States)

    Thomas, Nancy H.; Hora, J. L.; Smith, H. A.

    2013-01-01

    Young stellar objects (YSOs) are stars in the process of formation. Several recent investigations have shown a high rate of photometric variability in YSOs at near- and mid-infrared wavelengths. Theoretical models for the formation of massive stars (1-10 solar masses) remain highly idealized, and little is known about the mechanisms that produce the variability. An ongoing Spitzer Space Telescope program is studying massive star formation in the Cygnus-X region. In conjunction with the Spitzer observations, we have conducted a ground-based near-infrared observing program of the Cygnus-X DR21 field using PAIRITEL, the automated infrared telescope at Whipple Observatory. Using the Stetson index for variability, we identified variable objects and a number of variable YSOs in our time-series PAIRITEL data of DR21. We have searched for periodicity among our variable objects using the Lomb-Scargle algorithm, and identified periodic variable objects with an average period of 8.07 days. Characterization of these variable and periodic objects will help constrain models of star formation present. This work is supported in part by the NSF REU and DOD ASSURE programs under NSF grant no. 0754568 and by the Smithsonian Institution.

  7. Hydrodynamic ejection of bipolar flows from objects undergoing disk accretion: T Tauri stars, massive pre-main-sequence objects, and cataclysmic variables

    International Nuclear Information System (INIS)

    Torbett, M.V.

    1984-01-01

    A general mechanism is presented for generating pressure-driven winds that are intrinsically bipolar from objects undergoing disk accretion. The energy librated in a boundary layer shock as the disk matter impacts the central object is shown to be sufficient to eject a fraction βapprox.10 -2 to 10 -3 of the accreted mass. These winds are driven by a mechanism that accelerates the flow perpendicular to the plane of the disk and can therefore account for the bipolar geometry of the mass loss observed near young stars. The mass loss contained in these winds is comparable to that inferred for young stars. Thus, disk accretion-driven winds may constitute the T Tauri phase of stellar evolution. This mechanism is generally applicable, and thus massive pre-main-sequence objects as well as cataclysmic variables at times of enhanced accretion are predicted to eject bipolar outflows as well. Unmagnetized accreting neutron stas are also expected to eject bipolar flows. Since this mechanism requires stellar surfaces, however, it will not operate in disk accretion onto black holes

  8. A STRING OF RADIO EMISSION ASSOCIATED WITH IRAS 16562-3959: A COLLIMATED JET EMANATING FROM A LUMINOUS MASSIVE YOUNG STELLAR OBJECT

    International Nuclear Information System (INIS)

    Guzman, Andres E.; Garay, Guido; Brooks, Kate J.

    2010-01-01

    We report the discovery, made using the Australia Telescope Compact Array, of a remarkable string of radio emission toward IRAS 16562-3959, a luminous infrared source with a bolometric luminosity of 7.0 x 10 4 L sun . The radio emission arises from a compact, bright central component, two inner lobes which are separated by about 7'' and symmetrically offset from the central source, and two outer lobes which are separated by about 45''. The emission from the central object has a spectral index between 1.4 and 8.6 GHz of 0.85 ± 0.15, consistent with free-free emission from a thermal jet. The radio emission from the lobes has spectral indices in the range characteristic of thermal emission. We suggest that the emission from the lobes arises in shocks resulting from the interaction of a collimated wind with the surrounding medium. The radio string is located within a massive dense molecular core, and is associated with extended green emission (Spitzer three-color), Herbig-Haro-type emission (2MASS K s band), and OH maser sites-all phenomena readily observed toward sites of massive star formation. We conclude that the massive core hosts a high-mass star in an early stage of evolution in which it is undergoing the ejection of a powerful collimated stellar wind, showing that jets found in the formation of low-mass stars are also produced in high-mass stars.

  9. Quantum superposition of massive objects and collapse models

    International Nuclear Information System (INIS)

    Romero-Isart, Oriol

    2011-01-01

    We analyze the requirements to test some of the most paradigmatic collapse models with a protocol that prepares quantum superpositions of massive objects. This consists of coherently expanding the wave function of a ground-state-cooled mechanical resonator, performing a squared position measurement that acts as a double slit, and observing interference after further evolution. The analysis is performed in a general framework and takes into account only unavoidable sources of decoherence: blackbody radiation and scattering of environmental particles. We also discuss the limitations imposed by the experimental implementation of this protocol using cavity quantum optomechanics with levitating dielectric nanospheres.

  10. Quantum superposition of massive objects and collapse models

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Isart, Oriol [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching (Germany)

    2011-11-15

    We analyze the requirements to test some of the most paradigmatic collapse models with a protocol that prepares quantum superpositions of massive objects. This consists of coherently expanding the wave function of a ground-state-cooled mechanical resonator, performing a squared position measurement that acts as a double slit, and observing interference after further evolution. The analysis is performed in a general framework and takes into account only unavoidable sources of decoherence: blackbody radiation and scattering of environmental particles. We also discuss the limitations imposed by the experimental implementation of this protocol using cavity quantum optomechanics with levitating dielectric nanospheres.

  11. YOUNG STELLAR OBJECTS IN THE MASSIVE STAR-FORMING REGION W49

    Energy Technology Data Exchange (ETDEWEB)

    Saral, G.; Hora, J. L.; Willis, S. E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Koenig, X. P. [Yale University, Department of Astronomy, 208101, New Haven, CT 06520-8101 (United States); Gutermuth, R. A. [University of Massachusetts, Department of Astronomy, Amherst, MA 01003 (United States); Saygac, A. T., E-mail: gsaral@cfa.harvard.edu [Istanbul University, Faculty of Science, Astronomy and Space Sciences Department, Istanbul-Turkey (Turkey)

    2015-11-01

    We present the initial results of our investigation of the star-forming complex W49, one of the youngest and most luminous massive star-forming regions in our Galaxy. We used Spitzer/Infrared Array Camera (IRAC) data to investigate massive star formation with the primary objective of locating a representative set of protostars and the clusters of young stars that are forming around them. We present our source catalog with the mosaics from the IRAC data. In this study we used a combination of IRAC, MIPS, Two Micron All Sky Survey, and UKIRT Deep Infrared Sky Survey (UKIDSS) data to identify and classify the young stellar objects (YSOs). We identified 232 Class 0/I YSOs, 907 Class II YSOs, and 74 transition disk candidate objects using color–color and color–magnitude diagrams. In addition, to understand the evolution of star formation in W49, we analyzed the distribution of YSOs in the region to identify clusters using a minimal spanning tree method. The fraction of YSOs that belong to clusters with ≥7 members is found to be 52% for a cutoff distance of 96″, and the ratio of Class II/I objects is 2.1. We compared the W49 region to the G305 and G333 star-forming regions and concluded that W49 has the richest population, with seven subclusters of YSOs.

  12. Medium-resolution near-infrared spectroscopy of massive young stellar objects

    Science.gov (United States)

    Pomohaci, R.; Oudmaijer, R. D.; Lumsden, S. L.; Hoare, M. G.; Mendigutía, I.

    2017-12-01

    We present medium-resolution (R ∼ 7000) near-infrared echelle spectroscopic data for 36 massive young stellar objects (MYSOs) drawn from the Red MSX Source survey. This is the largest sample observed at this resolution at these wavelengths of MYSOs to date. The spectra are characterized mostly by emission from hydrogen recombination lines and accretion diagnostic lines. One MYSO shows photospheric H I absorption, a comparison with spectral standards indicates that the star is an A-type star with a low surface gravity, implying that the MYSOs are probably swollen, as also suggested by evolutionary calculations. An investigation of the Brγ line profiles shows that most are in pure emission, while 13 ± 5 per cent display P Cygni profiles, indicative of outflow, while less than 8 ± 4 per cent have inverse P Cygni profiles, indicative of infall. These values are comparable with investigations into the optically bright Herbig Be stars, but not with those of Herbig Ae and T Tauri stars, consistent with the notion that the more massive stars undergo accretion in a different fashion than lower mass objects that are undergoing magnetospheric accretion. Accretion luminosities and rates as derived from the Br γ line luminosities agree with results for lower mass sources, providing tentative evidence for massive star formation theories based on scaling of low-mass scenarios. We present Br γ/Br12 line profile ratios exploiting the fact that optical depth effects can be traced as a function of Doppler shift across the lines. These show that the winds of MYSOs in this sample are nearly equally split between constant, accelerating and decelerating velocity structures. There are no trends between the types of features we see and bolometric luminosities or near-infrared colours.

  13. Thermal evolution of massive compact objects with dense quark cores

    International Nuclear Information System (INIS)

    Hess, Daniel; Sedrakian, Armen

    2011-01-01

    We examine the thermal evolution of a sequence of compact objects containing low-mass hadronic and high-mass quark-hadronic stars constructed from a microscopically motivated equation of state. The dependence of the cooling tracks in the temperature versus age plane is studied on the variations of the gaplessness parameter (the ratio of the pairing gap for red-green quarks to the electron chemical potential) and the magnitude of blue quark gap. The pairing in the red-green channel is modeled assuming an inhomogeneous superconducting phase to avoid tachionic instabilities and anomalies in the specific heat; the blue colored condensate is modeled as a Bardeen-Cooper-Schrieffer (BCS)-type color superconductor. We find that massive stars containing quark matter cool faster in the neutrino-cooling era if one of the colors (blue) is unpaired and/or the remaining colors (red-green) are paired in a inhomogeneous gapless superconducting state. The cooling curves show significant variations along the sequence, as the mass (or the central density) of the models is varied. This feature provides a handle for fine-tuning the models to fit the data on the surface temperatures of same-age neutron stars. In the late-time photon cooling era we observe inversion in the temperature arrangement of models, i.e., stars experiencing fast neutrino cooling are asymptotically hotter than their slowly cooling counterparts.

  14. Manycore processing of repeated range queries over massive moving objects observations

    DEFF Research Database (Denmark)

    Lettich, Francesco; Orlando, Salvatore; Silvestri, Claudio

    2014-01-01

    decomposition and allows to tackle effectively a broad range of spatial object distributions, even those very skewed. Also, to deal with the architectural peculiarities and limitations of the GPUs, we adopt non-trivial GPU data structures that avoid the need of locked memory accesses and favour coalesced memory...... accesses, thus enhancing the overall memory throughput. To the best of our knowledge this is the first work that exploits GPUs to efficiently solve repeated range queries over massive sets of continuously moving objects, characterized by highly skewed spatial distributions. In comparison with state...

  15. SALT Spectroscopy of Evolved Massive Stars

    Science.gov (United States)

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

    2017-06-01

    Long-slit spectroscopy with the Southern African Large Telescope (SALT) of central stars of mid-infrared nebulae detected with the Spitzer Space Telescope and Wide-Field Infrared Survey Explorer (WISE) led to the discovery of numerous candidate luminous blue variables (cLBVs) and other rare evolved massive stars. With the recent advent of the SALT fiber-fed high-resolution echelle spectrograph (HRS), a new perspective for the study of these interesting objects is appeared. Using the HRS we obtained spectra of a dozen newly identified massive stars. Some results on the recently identified cLBV Hen 3-729 are presented.

  16. A different method for calculation of the deflection angle of light passing close to a massive object by Fermat's principle

    Science.gov (United States)

    Akkus, Harun

    2013-12-01

    We introduce a method for calculating the amount of deflection angle of light passing close to a massive object. It is based on Fermat's principle. The varying refractive index of medium around the massive object is obtained from the Buckingham pi-theorem.

  17. Visual long-term memory has a massive storage capacity for object details

    OpenAIRE

    Brady, Timothy F.; Konkle, Talia; Alvarez, George A.; Oliva, Aude

    2008-01-01

    One of the major lessons of memory research has been that human memory is fallible, imprecise, and subject to interference. Thus, although observers can remember thousands of images, it is widely assumed that these memories lack detail. Contrary to this assumption, here we show that long-term memory is capable of storing a massive number of objects with details from the image. Participants viewed pictures of 2,500 objects over the course of 5.5 h. Afterward, they were shown pairs of images an...

  18. Luminous Herbig-Haro objects from a massive protostar: The unique case of HH 80/81

    Science.gov (United States)

    Reipurth, Bo

    2017-08-01

    Herbig-Haro (HH) objects are the optical manifestations of shock waves excited by outflows from young stars. They represent one of the few classes of spatially extended astronomical objects where both structural changes and proper motions can be measured on time scales of years to decades. HH 80/81 is a pair of HH objects in Sagittarius which are the intrinsically most luminous HH objects known. The driving source of HH 80/81 is the embedded star IRAS 18162-2048, which has a luminosity of 20,000 Lsun and excites a compact HII region, suggesting that it is a newborn massive star. HH objects associated with massive young stars are very rare, only a handful of cases are known, but what makes the HH 80/81 source unique among massive protostars is that it produces a finely collimated bipolar radio jet with extremely high velocity and pointing straight to HH 80/81. We propose to observe the HH 80/81 complex with WFC3 and the following four filters: Halpha 6563, Hbeta 4861, [SII] 6717/31, and [OIII] 5007. First epoch HST images were obtained 22 years ago, which now allows a very precise determination of proper motions. Groundbased optical and radio proper motions are not only uncertain, but actually contradict each other, a controversy that will be resolved by HST. The fine resolution of WFC3 allows a study of both fine structural details and structural changes of the shocks. Finally we will use a sophisticated adaptive grid code to interpret the (de-reddened) line ratios across the shocks.

  19. A LARGE, MASSIVE, ROTATING DISK AROUND AN ISOLATED YOUNG STELLAR OBJECT

    International Nuclear Information System (INIS)

    Quanz, Sascha P.; Beuther, Henrik; Steinacker, Juergen; Linz, Hendrik; Krause, Oliver; Henning, Thomas; Birkmann, Stephan M.; Zhang Qizhou

    2010-01-01

    We present multi-wavelength observations and a radiative transfer model of a newly discovered massive circumstellar disk of gas and dust which is one of the largest disks known today. Seen almost edge-on, the disk is resolved in high-resolution near-infrared (NIR) images and appears as a dark lane of high opacity intersecting a bipolar reflection nebula. Based on molecular line observations, we estimate the distance to the object to be 3.5 kpc. This leads to a size for the dark lane of ∼10,500 AU but due to shadowing effects the true disk size could be smaller. In Spitzer/IRAC 3.6 μm images, the elongated shape of the bipolar reflection nebula is still preserved and the bulk of the flux seems to come from disk regions that can be detected due to the slight inclination of the disk. At longer IRAC wavelengths, the flux is mainly coming from the central regions penetrating directly through the dust lane. Interferometric observations of the dust continuum emission at millimeter wavelengths with the Submillimeter Array confirm this finding as the peak of the unresolved millimeter-emission coincides perfectly with the peak of the Spitzer/IRAC 5.8 μm flux and the center of the dark lane seen in the NIR images. Simultaneously acquired CO data reveal a molecular outflow along the northern part of the reflection nebula which seems to be the outflow cavity. An elongated gaseous disk component is also detected and shows signs of rotation. The emission is perpendicular to the molecular outflow and thus parallel to but even more extended than the dark lane in the NIR images. Based on the dust continuum and the CO observations, we estimate a disk mass of up to a few solar masses depending on the underlying assumptions. Whether the disk-like structure is an actual accretion disk or rather a larger-scale flattened envelope or pseudodisk is difficult to discriminate with the current data set. The existence of HCO + /H 13 CO + emission proves the presence of dense gas in the disk

  20. Irradiation as a Method of Salvation of Cultural Heritage Objects Under Massive Jeopardy

    International Nuclear Information System (INIS)

    Katusin-Razem, B.; Braun, M.; Jagic, R.

    2013-01-01

    Cultural heritage artefacts made of organic materials are susceptible to deterioration caused by the action of insects, moulds, fungi and bacteria. The problem of biodeterioration becomes especially acute after natural catastrophes and weather inclemencies, or after human activities conducive to an abrupt development of pests. Usually a large number of objects are imperilled at the same time and their sheer number aggravates any organized preservation effort. Irradiation has proven an effective method of preservation under the circumstances, e.g. for the prevention of massive proliferation of fungal infestation of books wetted by flood. War destructions in Croatia 1991 - 1995 seriously jeopardized many cultural objects. Their treatment by 60Co gamma rays in the Radiation Chemistry and Dosimetry Laboratory of the Ruðer Boškoviæ Institute played a significant role in the prevention of massive biodeterioration. In co-operation with the Croatian Conservation Institute, one third of 5000 evacuated objects, mostly polychromic wooden sculptures, were irradiated for desinsection and disinfection, enabling their joint accommodation in depots until restoration. This contribution to the preservation of jeopardized cultural heritage objects has been recognized internationally as a specially significant and successful case of the application of irradiation to cultural heritage. The presentation describes in more detail the preservation and restoration of the altar of the Holy Cross from the church of the Blessed Virgin Mary of the Snow in Kamensko.(author)

  1. Ionised Jets Associated With Massive Young Stellar Objects

    Science.gov (United States)

    Purser, Simon John Derek

    2017-09-01

    This thesis focuses on the phenomena of ionised jets associated with massive young stellar objects. Firstly a study was conducted with the aim to establish a statistical sample of such objects. Radio observations towards a sample of 49 MYSOs resulted in the detection of 28 objects classified as ionised jets. The jets’ radio luminosities scaled with their MYSOs’ bolometric luminosities in the same way as for low-mass examples. This infers that the jet launching and collimation mechanisms of high-mass jets are very similar to that in their low-mass counterparts and they are ejected for the last ≤65000 yr of the MYSO phase. Interestingly non-thermal emission was regularly detected towards spatially distinct radio lobes (associated with ˜50% of the jets), suggesting the presence of synchrotron emission and therefore, magnetic fields. With an average spectral index of ¯α=‑0. 55 (indicative of the 1st order Fermi acceleration mechanism) it is concluded these lobes are the result of shocks in the jets’ stream. My second science chapter is a study of radio variability, precession and proper motions towards a subset of objects from the first chapter. Over a two year time period, no significant variability and only one example of proper motion (1800±600 km s‑1) was detected. Precession was found to be commonplace however and if it arises as the result of binary interactions, we infer orbital radii between 30 and 1800 au for the binary companions. Lastly, high-resolution, VLA observations at C and Q-bands were analysed to extend the known sample of MYSOs harbouring ionised jets into the northern hemisphere. Only 3 radio sources were detected possessing jet-like characteristics towards the work’s sub-sample of 8 IRDCs containing 44 mm-cores (in our field of view), highlighting the radio-quiet (≳30μJy) nature of this early phase in massive star formation. Towards the RMS survey derived sample of 48 MYSOs, a total of 38 radio sources with jet

  2. A Faster Parallel Algorithm and Efficient Multithreaded Implementations for Evaluating Betweenness Centrality on Massive Datasets

    Energy Technology Data Exchange (ETDEWEB)

    Madduri, Kamesh; Ediger, David; Jiang, Karl; Bader, David A.; Chavarria-Miranda, Daniel

    2009-02-15

    We present a new lock-free parallel algorithm for computing betweenness centralityof massive small-world networks. With minor changes to the data structures, ouralgorithm also achieves better spatial cache locality compared to previous approaches. Betweenness centrality is a key algorithm kernel in HPCS SSCA#2, a benchmark extensively used to evaluate the performance of emerging high-performance computing architectures for graph-theoretic computations. We design optimized implementations of betweenness centrality and the SSCA#2 benchmark for two hardware multithreaded systems: a Cray XMT system with the Threadstorm processor, and a single-socket Sun multicore server with the UltraSPARC T2 processor. For a small-world network of 134 million vertices and 1.073 billion edges, the 16-processor XMT system and the 8-core Sun Fire T5120 server achieve TEPS scores (an algorithmic performance count for the SSCA#2 benchmark) of 160 million and 90 million respectively, which corresponds to more than a 2X performance improvement over the previous parallel implementations. To better characterize the performance of these multithreaded systems, we correlate the SSCA#2 performance results with data from the memory-intensive STREAM and RandomAccess benchmarks. Finally, we demonstrate the applicability of our implementation to analyze massive real-world datasets by computing approximate betweenness centrality for a large-scale IMDb movie-actor network.

  3. Growth of a Massive Young Stellar Object Fed by a Gas Flow from a Companion Gas Clump

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xi; Shen, Zhiqiang [Shanghai Astronomical Observatories, Chinese Academy of Science, Nandan Rd. 80, Shanghai (China); Ren, Zhiyuan [National Astronomical Observatories, Chinese Academy of Science, Chaoyang District Datun Rd. A20, Beijing (China); Zhang, Qizhou [Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138 (United States); Qiu, Keping [School of Astronomy and Space Science, Nanjing University, 22 Hankou Rd., Nanjing, Jiangsu 210093 (China)

    2017-02-01

    We present a Submillimeter Array (SMA) observation toward the young massive double-core system G350.69-0.49. This system consists of a northeast (NE) diffuse gas bubble and a southwest (SW) massive young stellar object (MYSO), both clearly seen in the Spitzer images. The SMA observations reveal a gas flow between the NE bubble and the SW MYSO in a broad velocity range from 5 to 30 km s{sup −1} with respect to the system velocity. The gas flow is well confined within the interval between the two objects and traces a significant mass transfer from the NE gas bubble to the SW massive core. The transfer flow can supply the material accreted onto the SW MYSO at a rate of 4.2×10{sup −4} M{sub ⊙} yr{sup −1}. The whole system therefore suggests a mode for the mass growth in the MYSO from a gas transfer flow launched from its companion gas clump, despite the driving mechanism of the transfer flow not being fully determined from the current data.

  4. Very massive runaway stars from three-body encounters

    Science.gov (United States)

    Gvaramadze, Vasilii V.; Gualandris, Alessia

    2011-01-01

    Very massive stars preferentially reside in the cores of their parent clusters and form binary or multiple systems. We study the role of tight very massive binaries in the origin of the field population of very massive stars. We performed numerical simulations of dynamical encounters between single (massive) stars and a very massive binary with parameters similar to those of the most massive known Galactic binaries, WR 20a and NGC 3603-A1. We found that these three-body encounters could be responsible for the origin of high peculiar velocities (≥70 km s-1) observed for some very massive (≥60-70 M⊙) runaway stars in the Milky Way and the Large Magellanic Cloud (e.g. λ Cep, BD+43°3654, Sk -67°22, BI 237, 30 Dor 016), which can hardly be explained within the framework of the binary-supernova scenario. The production of high-velocity massive stars via three-body encounters is accompanied by the recoil of the binary in the opposite direction to the ejected star. We show that the relative position of the very massive binary R145 and the runaway early B-type star Sk-69°206 on the sky is consistent with the possibility that both objects were ejected from the central cluster, R136, of the star-forming region 30 Doradus via the same dynamical event - a three-body encounter.

  5. Visual long-term memory has a massive storage capacity for object details.

    Science.gov (United States)

    Brady, Timothy F; Konkle, Talia; Alvarez, George A; Oliva, Aude

    2008-09-23

    One of the major lessons of memory research has been that human memory is fallible, imprecise, and subject to interference. Thus, although observers can remember thousands of images, it is widely assumed that these memories lack detail. Contrary to this assumption, here we show that long-term memory is capable of storing a massive number of objects with details from the image. Participants viewed pictures of 2,500 objects over the course of 5.5 h. Afterward, they were shown pairs of images and indicated which of the two they had seen. The previously viewed item could be paired with either an object from a novel category, an object of the same basic-level category, or the same object in a different state or pose. Performance in each of these conditions was remarkably high (92%, 88%, and 87%, respectively), suggesting that participants successfully maintained detailed representations of thousands of images. These results have implications for cognitive models, in which capacity limitations impose a primary computational constraint (e.g., models of object recognition), and pose a challenge to neural models of memory storage and retrieval, which must be able to account for such a large and detailed storage capacity.

  6. Central charges, S-duality and massive vacua of N=1* super-Yang-Mills

    International Nuclear Information System (INIS)

    Ritz, Adam

    2006-01-01

    We provide a simple derivation of the extremal values of the superpotential in massive vacua of N=1* SYM, making use of the required modular weight for the central charge of BPS walls interpolating between these vacua. This modular weight descends from the action of S-duality on the N=4 superalgebra which in turn is inherited from its classical action on the dyon spectrum. We show that this kinematic information, combined with minimal knowledge of the weak coupling asymptotics, is sufficient to determine the exact vacuum superpotentials in terms of Eisenstein series

  7. Minimal massive 3D gravity

    International Nuclear Information System (INIS)

    Bergshoeff, Eric; Merbis, Wout; Hohm, Olaf; Routh, Alasdair J; Townsend, Paul K

    2014-01-01

    We present an alternative to topologically massive gravity (TMG) with the same ‘minimal’ bulk properties; i.e. a single local degree of freedom that is realized as a massive graviton in linearization about an anti-de Sitter (AdS) vacuum. However, in contrast to TMG, the new ‘minimal massive gravity’ has both a positive energy graviton and positive central charges for the asymptotic AdS-boundary conformal algebra. (paper)

  8. Evolution and alteration in situ of a massive iron duricrust in Central Africa

    Science.gov (United States)

    Bitom, Dieudonné; Volkoff, Boris; Abossolo-Angue, Monique

    2003-08-01

    A soil sequence with iron duricrust is described in an area covered by tropical rain forest in South Cameroon. The dismantling of the iron duricrust is documented through a close observation of a soft duricrust, which corresponds to a transitional stage in the degradation of a massive iron duricrust into a loose nodular horizon. In the initial massive and hematitic duricrust, nodular shapes are progressively formed. The nodules and the internodular matrix remain hematitic. The internodular matrix undergoes goethitization and a pronounced deferruginisation before loosening; the primary structure of the iron duricrust is maintained, however, due to internodular bridges, relics of internodular matrix which escaped the process of goethitization. The iron is gradually released from these hematitic bridges, which become softer. This leads to the collapse of the initial structures of the iron duricrust and to the formation of a loose nodular material with a clayey matrix containing kaolinite and goethite. Many loose nodular horizons, which are found all over Central Africa, may have been formed by such alteration of a former iron duricrust.

  9. Generalized status epilepticus associated with massive pulmonary aspiration and transient central diabetes insipidus: case report

    Directory of Open Access Journals (Sweden)

    CARVALHO MAURICIO

    2000-01-01

    Full Text Available Status epilepticus causes significant morbidity and mortality. A case of generalized status epilepticus followed by massive pulmonary aspiration, acute respiratory failure and transient central diabetes insipidus is presented. Seizures were promptly controlled, but the patient required mechanical ventilation and correction of polyuria with desmopressin acetate. During hospitalization mental status improved, diabetes insipidus spontaneously remitted and he was discharged without neurologic sequelae. The clinical and pathophysiological features of this case are discussed.

  10. Einstein-Podolsky-Rosen-entangled motion of two massive objects

    Science.gov (United States)

    Schnabel, Roman

    2015-07-01

    In 1935, Einstein, Podolsky, and Rosen (EPR) considered two particles in an entangled state of motion to illustrate why they questioned the completeness of quantum theory. In past decades, microscopic systems with entanglement in various degrees of freedom have successfully been generated, representing compelling evidence to support the completeness of quantum theory. Today, the generation of an EPR-entangled state of motion of two massive objects of up to the kilogram scale seems feasible with state-of-the-art technology. Recently, the generation and verification of EPR-entangled mirror motion in interferometric gravitational wave detectors was proposed, with the aim of testing quantum theory in the regime of macroscopic objects, and to make available nonclassical probe systems for future tests of modified quantum theories that include (nonrelativistic) gravity. The work presented here builds on these earlier results and proposes a specific Michelson interferometer that includes two high-quality laser mirrors of about 0.1 kg mass each. The mirrors are individually suspended as pendula and located close to each other, and cooled to about 4 K. The physical concepts for the generation of the EPR-entangled center-of-mass motion of these two mirrors are described. Apart from a test of quantum mechanics in the macroscopic world, the setup is envisioned to test predictions of yet-to-be-elaborated modified quantum theories that include gravitational effects.

  11. A different method for calculation of the deflection angle of light passing close to a massive object by Fermat’s principle

    Energy Technology Data Exchange (ETDEWEB)

    Akkus, Harun, E-mail: physicisthakkus@gmail.com

    2013-12-15

    We introduce a method for calculating the amount of deflection angle of light passing close to a massive object. It is based on Fermat’s principle. The varying refractive index of medium around the massive object is obtained from the Buckingham pi-theorem. Highlights: •A different and simpler method for the calculation of deflection angle of light. •Not a curved space, only 2-D Euclidean space. •Getting a varying refractive index from the Buckingham pi-theorem. •Obtaining the some results of general relativity from Fermat’s principle.

  12. A different method for calculation of the deflection angle of light passing close to a massive object by Fermat’s principle

    International Nuclear Information System (INIS)

    Akkus, Harun

    2013-01-01

    We introduce a method for calculating the amount of deflection angle of light passing close to a massive object. It is based on Fermat’s principle. The varying refractive index of medium around the massive object is obtained from the Buckingham pi-theorem. Highlights: •A different and simpler method for the calculation of deflection angle of light. •Not a curved space, only 2-D Euclidean space. •Getting a varying refractive index from the Buckingham pi-theorem. •Obtaining the some results of general relativity from Fermat’s principle

  13. Complex organic molecules in organic-poor massive young stellar objects

    DEFF Research Database (Denmark)

    Fayolle, Edith C.; Öberg, Karin I.; Garrod, Robin T.

    2015-01-01

    to search for complex organic molecules over 8-16 GHz in the 1 mm atmospheric window toward three MYSOs with known ice abundances, but without luminous molecular hot cores. Results. Complex molecules are detected toward all three sources at comparable abundances with respect to CH3OH to classical hot core......Context. Massive young stellar objects (MYSOs) with hot cores are classic sources of complex organic molecules. The origins of these molecules in such sources, as well as the small-and large-scale differentiation between nitrogen-and oxygen-bearing complex species, are poorly understood. Aims. We...... aim to use complex molecule abundances toward a chemically less explored class of MYSOs with weak hot organic emission lines to constrain the impact of hot molecular cores and initial ice conditions on the chemical composition toward MYSOs. Methods. We use the IRAM 30 m and the Submillimeter Array...

  14. The establishment of animal model of acute massive pulmonary embolism

    International Nuclear Information System (INIS)

    Lu Junliang; Yang Ning; Yang Jianping; Ma Junshan; Zhao Shijun

    2008-01-01

    Objective: To find a way of establishing the model of acute massive pulmonary embolism in dog. Methods: Seven dogs were selected with self-clots made outside the body transferring through a 10 F guiding catheter into the central branch of pulmonary artery via the femoral vein approach on one side and then under pressure monitor of pulmonary artery until the very branch of pulmonary artery was occluded. Blood gas and pulmonary arterial pressure were tested before and after the embolization, Pulmonary artery pressure was continuously monitored together with the examinations of angiography. The bilateral lung specimens were resected for histological examination 12 hours in average after the embolization for comparative study. Results: One animal died of cardiogenic shock after clots injection; the other one presented with tachycardia and premature ventricular beat causing partial recanalization 12 h later. The others were occluded successfully in central branch of pulmonary artery and the pulmonary arterial pressure reached above 50 mmHg after occlusion. Pathologic examination showed the formation of red and mix thrombi within the vascular lumens. Conclusions: This method for making acute massive pulmonary embolism animal model was reliable, feasible and reproducible, and could provide an animal model of acute massive pulmonary embolism for other correlative experiments. (authors)

  15. Oscillating shells: A model for a variable cosmic object

    OpenAIRE

    Nunez, Dario

    1997-01-01

    A model for a possible variable cosmic object is presented. The model consists of a massive shell surrounding a compact object. The gravitational and self-gravitational forces tend to collapse the shell, but the internal tangential stresses oppose the collapse. The combined action of the two types of forces is studied and several cases are presented. In particular, we investigate the spherically symmetric case in which the shell oscillates radially around a central compact object.

  16. Topological massive sigma models

    International Nuclear Information System (INIS)

    Lambert, N.D.

    1995-01-01

    In this paper we construct topological sigma models which include a potential and are related to twisted massive supersymmetric sigma models. Contrary to a previous construction these models have no central charge and do not require the manifold to admit a Killing vector. We use the topological massive sigma model constructed here to simplify the calculation of the observables. Lastly it is noted that this model can be viewed as interpolating between topological massless sigma models and topological Landau-Ginzburg models. ((orig.))

  17. Resolved 24.5 micron emission from massive young stellar objects

    Science.gov (United States)

    de Wit, W. J.; Hoare, M. G.; Fujiyoshi, T.; Oudmaijer, R. D.; Honda, M.; Kataza, H.; Miyata, T.; Okamoto, Y. K.; Onaka, T.; Sako, S.; Yamashita, T.

    2009-01-01

    Context: Massive young stellar objects (MYSO) are surrounded by massive dusty envelopes, whose physical structure and geometry are determined by the star formation process. Aims: Our principal aim is to establish the density structure of MYSO envelopes on scales of ~1000 AU. This constitutes an increase of a factor ~10 in angular resolution compared to similar studies performed in the (sub)mm. Methods: We have obtained diffraction-limited (0.6´´) 24.5 μm images (field of view of 40 arcsec×30 arcsec) of 14 well-known massive star formation regions with the COMICS instrument mounted on the 8.2 m Subaru telescope. We construct azimuthally averaged intensity profiles of the resolved MYSO envelopes and build spectral energy distributions (SEDs) from archival data and the COMICS 24.5 μm flux density. The SEDs range from near-infrared to millimeter wavelengths. Self-consistent 1-D radiative transfer models described by a density dependence of the form n(r) ∝ r-p are used to simultaneously compare the intensity profiles and SEDs to model predictions. Results: The images reveal the presence of discrete MYSO sources which are resolved on arcsecond scales, and, to first-order, the observed emission is circular on the sky. For many sources, the spherical models are capable of satisfactorily reproducing the 24.5 μm intensity profile, the 24.5 μm flux density, the 9.7 μm silicate absorption feature, and the submm emission. They are described by density distributions with p =1.0±0.25. Such distributions are shallower than those found on larger scales probed with single-dish (sub)mm studies. Other sources have density laws that are shallower/steeper than p=1.0 and there is evidence that these are viewed near edge-on or near face-on respectively. In these cases spherical models fail to provide good fits to the data. The images also reveal a diffuse component tracing somewhat larger scale structures, particularly visible in the regions S 140, AFGL 2136, IRAS 20126

  18. Revealing evolved massive stars with Spitzer

    Science.gov (United States)

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

    2010-06-01

    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 24-μm 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). We interpret this similarity as an indication that the central stars of detected nebulae are either LBVs or related evolved massive stars. Our interpretation is supported by follow-up spectroscopy of two dozen of these central stars, most of which turn out to be either candidate LBVs (cLBVs), blue supergiants or WNL stars. We expect that the forthcoming spectroscopy of the remaining objects from our list, accompanied by the spectrophotometric monitoring of the already discovered cLBVs, will further increase the known population of Galactic LBVs. This, in turn, will have profound consequences for better understanding the LBV phenomenon and its role in the transition between hydrogen-burning O stars and helium-burning WR stars. We also report on the detection of an arc-like structure attached to the cLBV HD 326823 and an arc associated with the LBV R99 (HD 269445) in the LMC. Partially based on observations collected at the German-Spanish Astronomical Centre, Calar Alto, jointly operated by the Max-Planck-Institut für Astronomie Heidelberg and the Instituto de Astrofísica de Andalucía (CSIC). E-mail: vgvaram@mx.iki.rssi.ru (VVG); akniazev@saao.ac.za (AYK); fabrika@sao.ru (SF)

  19. The fate of high redshift massive compact galaxies in dense environments

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, Tobias; /Zurich, ETH; Mayer, Lucio; /Zurich U.; Carollo, Marcella; /Zurich, ETH; Feldmann, Robert; /Fermilab /Chicago U., KICP

    2012-01-01

    Massive compact galaxies seem to be more common at high redshift than in the local universe, especially in denser environments. To investigate the fate of such massive galaxies identified at z {approx} 2 we analyse the evolution of their properties in three cosmological hydrodynamical simulations that form virialized galaxy groups of mass {approx} 10{sup 13} M{sub {circle_dot}} hosting a central massive elliptical/S0 galaxy by redshift zero. We find that at redshift {approx} 2 the population of galaxies with M{sub *} > 2 x 10{sup 10} M{sub {circle_dot}} is diverse in terms of mass, velocity dispersion, star formation and effective radius, containing both very compact and relatively extended objects. In each simulation all the compact satellite galaxies have merged into the central galaxy by redshift 0 (with the exception of one simulation where one of such satellite galaxy survives). Satellites of similar mass at z = 0 are all less compact than their high redshift counterparts. They form later than the galaxies in the z = 2 sample and enter the group potential at z < 1, when dynamical friction times are longer than the Hubble time. Also, by z = 0 the central galaxies have increased substantially their characteristic radius via a combination of in situ star formation and mergers. Hence in a group environment descendants of compact galaxies either evolve towards larger sizes or they disappear before the present time as a result of the environment in which they evolve. Since the group-sized halos that we consider are representative of dense environments in the {Lambda}CDM cosmology, we conclude that the majority of high redshift compact massive galaxies do not survive until today as a result of the environment.

  20. Towards a formalism for mapping the spacetimes of massive compact objects: Bumpy black holes and their orbits

    International Nuclear Information System (INIS)

    Collins, Nathan A.; Hughes, Scott A.

    2004-01-01

    Astronomical observations have established that extremely compact, massive objects are common in the Universe. It is generally accepted that these objects are, in all likelihood, black holes. As observational technology has improved, it has become possible to test this hypothesis in ever greater detail. In particular, it is or will be possible to measure the properties of orbits deep in the strong field of a black hole candidate (using x-ray timing or future gravitational-wave measurements) and to test whether they have the characteristics of black hole orbits in general relativity. Past work has shown that, in principle, such measurements can be used to map the spacetime of a massive compact object, testing in particular whether the object's multipolar structure satisfies the rather strict constraints imposed by the black hole hypothesis. Performing such a test in practice requires that we be able to compare against objects with the 'wrong' multipole structure. In this paper, we present tools for constructing the spacetimes of bumpy black holes: objects that are almost black holes, but that have some multipoles with the wrong value. In this first analysis, we focus on objects with no angular momentum. Generalization to bumpy Kerr black holes should be straightforward, albeit labor intensive. Our construction has two particularly desirable properties. First, the spacetimes which we present are good deep into the strong field of the object--we do not use a 'large r' expansion (except to make contact with weak field intuition). Second, our spacetimes reduce to the exact black hole spacetimes of general relativity in a natural way, by dialing the 'bumpiness' of the black hole to zero. We propose that bumpy black holes can be used as the foundation for a null experiment: if black hole candidates are indeed the black holes of general relativity, their bumpiness should be zero. By comparing the properties of orbits in a bumpy spacetime with those measured from an

  1. Young Stellar Objects in the Massive Star-forming Regions W51 and W43

    Energy Technology Data Exchange (ETDEWEB)

    Saral, G.; Audard, M. [Department of Astronomy, University of Geneva, Ch. d’Ecogia 16, 1290 Versoix (Switzerland); Hora, J. L.; Martínez-Galarza, J. R.; Smith, H. A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Koenig, X. P. [Yale University, Department of Astronomy, 208101, New Haven, CT 06520-8101 (United States); Motte, F. [Institut de Plantologie et d’Astrophysique de Grenoble, Univ. Grenoble Alpes—CNRS-INSU, BP 53, F-38041 Grenoble Cedex 9 (France); Nguyen-Luong, Q. [National Astronomical Observatory of Japan, Chile Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Saygac, A. T. [Istanbul University, Faculty of Science, Astronomy and Space Sciences Department, Istanbul-Turkey (Turkey)

    2017-04-20

    We present the results of our investigation of the star-forming complexes W51 and W43, two of the brightest in the first Galactic quadrant. In order to determine the young stellar object (YSO) populations in W51 and W43 we used color–magnitude relations based on Spitzer mid-infrared and 2MASS/UKIDSS near-infrared data. We identified 302 Class I YSOs and 1178 Class II/transition disk candidates in W51, and 917 Class I YSOs and 5187 Class II/transition disk candidates in W43. We also identified tens of groups of YSOs in both regions using the Minimal Spanning Tree (MST) method. We found similar cluster densities in both regions, even though Spitzer was not able to probe the densest part of W43. By using the Class II/I ratios, we traced the relative ages within the regions and, based on the morphology of the clusters, we argue that several sites of star formation are independent of one another in terms of their ages and physical conditions. We used spectral energy distribution-fitting to identify the massive YSO (MYSO) candidates since they play a vital role in the star formation process, and then examined them to see if they are related to any massive star formation tracers such as UCH ii regions, masers, or dense fragments. We identified 17 MYSO candidates in W51, and 14 in W43, respectively, and found that groups of YSOs hosting MYSO candidates are positionally associated with H ii regions in W51, though we do not see any MYSO candidates associated with previously identified massive dense fragments in W43.

  2. Growing massive black holes in a Local Group environment: the central supermassive, slowly sinking and ejected populations

    Science.gov (United States)

    Micic, Miroslav; Holley-Bockelmann, Kelly; Sigurdsson, Steinn

    2011-06-01

    We explore the growth of ≤107 M⊙ black holes that reside at the centres of spiral and field dwarf galaxies in a Local Group type of environment. We use merger trees from a cosmological N-body simulation known as Via Lactea 2 (VL-2) as a framework to test two merger-driven semi-analytic recipes for black hole growth that include dynamical friction, tidal stripping and gravitational wave recoil in over 20 000 merger tree realizations. First, we apply a Fundamental Plane limited (FPL) model to the growth of Sgr A*, which drives the central black hole to a maximum mass limited by the black hole Fundamental Plane after every merger. Next, we present a new model that allows for low-level prolonged gas accretion (PGA) during the merger. We find that both models can generate an Sgr A* mass black hole. We predict a population of massive black holes in local field dwarf galaxies - if the VL-2 simulation is representative of the growth of the Local Group, we predict up to 35 massive black holes (≤106 M⊙) in Local Group field dwarfs. We also predict that hundreds of ≤105 M⊙ black holes fail to merge, and instead populate the Milky Way halo, with the most massive of them at roughly the virial radius. In addition, we find that there may be hundreds of massive black holes ejected from their hosts into the nearby intergalactic medium due to gravitational wave recoil. We discuss how the black hole population in the Local Group field dwarfs may help to constrain the growth mechanism for Sgr A*.

  3. Explosions of Thorne-Żytkow objects

    Science.gov (United States)

    Moriya, Takashi J.

    2018-03-01

    We propose that massive Thorne-Żytkow objects can explode. A Thorne-Żytkow object is a theoretically predicted star that has a neutron core. When nuclear reactions supporting a massive Thorne-Żytkow object terminate, a strong accretion occurs towards the central neutron core. The accretion rate is large enough to sustain a super-Eddington accretion towards the neutron core. The neutron core may collapse to a black hole after a while. A strong large-scale outflow or a jet can be launched from the super-Eddington accretion disc and the collapsing Thorne-Żytkow object can be turned into an explosion. The ejecta have about 10 M⊙ but the explosion energy depends on when the accretion is suppressed. We presume that the explosion energy could be as low as ˜1047 erg and such a low-energy explosion could be observed like a failed supernova. The maximum possible explosion energy is ˜1052 erg and such a high-energy explosion could be observed as an energetic Type II supernova or a superluminous supernova. Explosions of Thorne-Żytkow objects may provide a new path to spread lithium and other heavy elements produced through the irp process such as molybdenum in the Universe.

  4. Impact of morphologic characteristics of central pulmonary thromboemboli in massive pulmonary embolism.

    Science.gov (United States)

    Podbregar, Matej; Krivec, Bojan; Voga, Gorazd

    2002-09-01

    To assess the impact of morphologically different central pulmonary artery thromboemboli in patients with massive pulmonary emboli (MPEs) on short-term outcome. A prospective registry of consecutive patients. An 11-bed closed medical ICU at a 860-bed community general hospital Forty-seven patients with shock or hypotension due to MPE and central pulmonary thromboemboli detected by transesophageal echocardiography who were treated with thrombolysis between January 1994 and April 2000. Patients were divided into two groups according to the following characteristics of the detected thromboemboli: group 1, thrombi with one or more long, mobile parts; and group 2, immobile thrombi. Right heart catheterization was performed. The incidence of both types of thromboemboli was comparable. Groups 1 and 2 showed no differences in demographic data, risk factors for pulmonary embolism, length of preceding clinical symptoms, percentage of patients in shock, hemodynamic variables, serum lactate levels on hospital admission, and treatment. Seven fatal cases due to obstructive shock and right heart failure were present in group 2, but none were present in group 1 (7 of 23 patients vs 0 of 24 patients, respectively; p < 0.05). At 12 h, the cardiac index was lower in group 2 than in group 1 (2.6 +/- 1.0 vs 3.1 +/- 0.9 L/min/m(2), respectively; p < 0.05), and the central venous pressure (15.0 +/- 6.2 vs 12.5 +/- 3.7 mm Hg, respectively; p < 0.05) and total pulmonary resistance (12.9 +/- 5.9 vs 8.6 +/- 2.7 mm Hg/L/min/m(2), respectively; p < 0.001) were higher in group 2 compared to group 1. On hospital admission, inclusion in group 2 (p < 0.03; hazard ratio, 9.53; 95% confidence interval [CI], 1.19 to 76.47) and preexisting chronic medical or neurologic disease (p < 0.01; hazard ratio, 16.4; 95% CI, 1.97 to 136.3) were independent predictors of 30-day mortality. On hospital admission, morphology of the thromboemboli and the presence of pre-existing chronic medical or neurologic disease

  5. Morphologic characteristics of central pulmonary thromboemboli predict haemodynamic response in massive pulmonary embolism.

    Science.gov (United States)

    Podbregar, Matej; Voga, Gorazd; Krivec, Bojan

    2004-08-01

    On hospital admission, the morphology of the central pulmonary artery thromboemboli is an independent predictor of 30-day mortality in patients with massive pulmonary embolism (MPE). This may be due to the differential susceptibility of thromboemboli to thrombolysis. The aim of this study was to assess haemodynamic response to treatment in patients with MPE and morphologically different thromboemboli. Prospective observational study. An 11-bed closed medical ICU at a 860-bed community general hospital. Twelve consecutive patients with shock or hypotension due to MPE and central pulmonary thromboemboli detected by transesophageal echocardiography who were treated with thrombolysis between January 2000 through April 2002. Patients were divided into two groups according to the characteristics of detected central pulmonary thromboemboli: group 1, thrombi with one or more long, mobile parts; and group 2, immobile thrombi. Urokinase infusion was terminated when mixed venous oxygen saturation was stabilized above 60% for 15 min. At 2 h, the total pulmonary vascular resistance index was reduced more in group 1 than group 2 [from 27+/-12 mmHg/(l.min.m(2)) to 14+/-6 mmHg/(l.min.m(2)) (-52%) vs 27+/-8 mmHg/(l.min.m(2)) to 23+/-10 mmHg/(l.min.m(2)) (-15%), respectively, P=0.04]. In group 1 thrombolysis was terminated earlier than group 2 (89+/-40 min vs 210+/-62 min, respectively, P= 0.0024). The cumulative dose of urokinase used in group 1 was lower than group 2 (1.7+/-0.3 M i.u. vs 2.7+/-0.5 M i.u., respectively, P= 0.023). Haemodynamic stabilization is achieved faster in patients with mobile central thromboemboli detected by transesophageal echocardiography during MPE.

  6. HUBBLE SPACE TELESCOPE NICMOS POLARIZATION OBSERVATIONS OF THREE EDGE-ON MASSIVE YOUNG STELLAR OBJECTS

    International Nuclear Information System (INIS)

    Simpson, Janet P.; Colgan, Sean W. J.; Erickson, Edwin F.; Burton, Michael G.; Cotera, Angela S.; Hines, Dean C.; Whitney, Barbara A.

    2009-01-01

    Massive young stellar objects (YSOs), like low-mass YSOs, appear to be surrounded by optically thick envelopes and/or disks and have regions, often bipolar, that are seen in polarized scattered light at near-infrared wavelengths. We are using the 0.''2 spatial resolution of the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on Hubble Space Telescope to examine the structure of the disks and outflow regions of massive YSOs in star-forming regions within a few kpc of the Sun. Here we report on 2 μm polarimetry of NGC 6334 V and S255 IRS1. NGC 6334 V consists of a double-lobed bright reflection nebula seen against a dark region, probably an optically thick molecular cloud. Our polarization measurements show that the illuminating star lies ∼2'' south of the line connecting the two lobes; we do not detect this star at 2 μm, but there are a small radio source and a mid-infrared source at this location. S255 IRS1 consists of two YSOs (NIRS1 and NIRS3) with overlapping scattered light lobes and luminosities corresponding to early B stars. Included in IRS1 is a cluster of stars from whose polarization we determine the local magnetic field direction. Neither of the YSOs has its scattered light lobes aligned with this magnetic field. The line connecting the scattered light lobes of NIRS1 is twisted symmetrically around the star; the best explanation is that the star is part of a close binary and the outflow axis of NIRS1 is precessing as a result of non-coplanar disk and orbit. The star NIRS3 is also offset from the line connecting its two scattered light lobes. We suggest that all three YSOs show evidence of episodic ejection of material as they accrete from dense, optically thick envelopes.

  7. Evaluating the environmental criticality of massive objects in LEO for debris mitigation and remediation

    Science.gov (United States)

    Pardini, Carmen; Anselmo, Luciano

    2018-04-01

    Approximately 95% of the mass in Earth orbit is currently concentrated in about 6700 intact objects, of which nearly 80% are abandoned and more than 90% cannot be maneuvered. The intact objects abandoned in low Earth orbit (LEO) above 650 km, i.e. with an average residual lifetime of more than 25 years, represent the main potential mass reservoir for the generation of new detrimental orbital debris in case of mutual collisions with the existing debris environment, taking into account that an 800 g impactor may be sufficient, in principle, to shatter a 1000 kg spacecraft or rocket stage. Since the 1980's, several mitigation measures were promoted and agreed at the international level in order to prevent the occurrence of new breakups in space and put under control the accumulation of mass abandoned in orbit, but unfortunately the level of compliance with such guidelines, requirements or standards is still far from satisfactory. Moreover, the appearance on the scene of space activity of new private and government actors from a growing number of countries makes the proper management of the circumterrestrial space a task of increasing complexity, taking also into account the rapid emerging of new potential applications, disrupting technologies and operational approaches quite different from the past. In this rapidly evolving environment, it might be useful to have a simple and flexible instrument for evaluating the potential criticality for the environment of massive objects placed or abandoned in LEO. With this goal, in the last few years, a particular effort was devoted to the development of various "criticality indexes", then applied for evaluating many families of rocket bodies and selected spacecraft. In this paper, with the underlining ambition to be simple, intuitive and relevant, from an environmental point of view, a couple of the most complete indexes were coherently applied in order to assess the potential criticality of the most massive objects abandoned in

  8. ON THE NATURE OF THE ENIGMATIC OBJECT IRAS 19312+1950: A RARE PHASE OF MASSIVE STAR FORMATION?

    Energy Technology Data Exchange (ETDEWEB)

    Cordiner, M. A.; Charnley, S. B.; Milam, S. N. [Astrochemistry Laboratory, NASA Goddard Space Flight Center, Code 691, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Boogert, A. C. A. [Universities Space Research Association, Stratospheric Observatory for Infrared Astronomy, NASA Ames Research Center, MS 232-11, Moffett Field, CA 94035 (United States); Justtanont, K.; Wirström, E. S. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92, Onsala (Sweden); Cox, N. L. J. [Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, bus 2401, B-3001, Leuven (Belgium); Smith, R. G. [School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, Australian Defence Force Academy, Canberra ACT 2600 (Australia); Tielens, A. G. G. M. [Leiden Observatory, University of Leiden, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Keane, J. V., E-mail: martin.cordiner@nasa.gov [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)

    2016-09-01

    IRAS 19312+1950 is a peculiar object that has eluded firm characterization since its discovery, with combined maser properties similar to an evolved star and a young stellar object (YSO). To help determine its true nature, we obtained infrared spectra of IRAS 19312+1950 in the range 5–550 μ m using the Herschel and Spitzer space observatories. The Herschel PACS maps exhibit a compact, slightly asymmetric continuum source at 170 μ m, indicative of a large, dusty circumstellar envelope. The far-IR CO emission line spectrum reveals two gas temperature components: ≈0.22 M {sub ⊙} of material at 280 ± 18 K, and ≈1.6 M {sub ⊙} of material at 157 ± 3 K. The O i 63 μ m line is detected on-source but no significant emission from atomic ions was found. The HIFI observations display shocked, high-velocity gas with outflow speeds up to 90 km s{sup −1} along the line of sight. From Spitzer spectroscopy, we identify ice absorption bands due to H{sub 2}O at 5.8 μ m and CO{sub 2} at 15 μ m. The spectral energy distribution is consistent with a massive, luminous (∼2 × 10{sup 4} L {sub ⊙}) central source surrounded by a dense, warm circumstellar disk and envelope of total mass ∼500–700 M {sub ⊙}, with large bipolar outflow cavities. The combination of distinctive far-IR spectral features suggest that IRAS 19312+1950 should be classified as an accreting, high-mass YSO rather than an evolved star. In light of this reclassification, IRAS 19312+1950 becomes only the fifth high-mass protostar known to exhibit SiO maser activity, and demonstrates that 18 cm OH maser line ratios may not be reliable observational discriminators between evolved stars and YSOs.

  9. On the Nature of the Enigmatic Object IRAS 19312+1950: A Rare Phase of Massive Star Formation?

    Science.gov (United States)

    Cordiner, M. A.; Boogert, A. C. A.; Charnley, S. B.; Justtanont, K.; Cox, N. L. J.; Smith, R. G.; Tielens, A. G. G. M.; Wirstrom, E. S.; Milam, S. N.; Keane, J. V.

    2016-01-01

    IRAS?19312+1950 is a peculiar object that has eluded firm characterization since its discovery, with combined maser properties similar to an evolved star and a young stellar object (YSO). To help determine its true nature, we obtained infrared spectra of IRAS?19312+1950 in the range 5-550 microns using the Herschel and Spitzer space observatories. The Herschel PACS maps exhibit a compact, slightly asymmetric continuum source at 170 microns, indicative of a large, dusty circumstellar envelope. The far-IR CO emission line spectrum reveals two gas temperature components: approx. = 0.22 Stellar Mass of material at 280+/-18 K, and ˜1.6 Me of material at 157+/-3 K. The OI 63 micron line is detected on-source but no significant emission from atomic ions was found. The HIFI observations display shocked, high-velocity gas with outflow speeds up to 90 km/s along the line of sight. From Spitzer spectroscopy, we identify ice absorption bands due to H2O at 5.8 microns and CO2 at 15 microns. The spectral energy distribution is consistent with a massive, luminous (approx. 2 × 10(exp 4) Stellar Luminosity) central source surrounded by a dense, warm circumstellar disk and envelope of total mass approx. 500-700 Stellar Mass with large bipolar outflow cavities. The combination of distinctive far-IR spectral features suggest that IRAS19312+1950 should be classified as an accreting, high-mass YSO rather than an evolved star. In light of this reclassification, IRAS19312+1950 becomes only the fifth high-mass protostar known to exhibit SiO maser activity, and demonstrates that 18 cm OH maser line ratios may not be reliable observational discriminators between evolved stars and YSOs.

  10. SECULAR EVOLUTION OF BINARIES NEAR MASSIVE BLACK HOLES: FORMATION OF COMPACT BINARIES, MERGER/COLLISION PRODUCTS AND G2-LIKE OBJECTS

    International Nuclear Information System (INIS)

    Prodan, Snezana; Antonini, Fabio; Perets, Hagai B.

    2015-01-01

    Here we discuss the evolution of binaries around massive black holes (MBHs) in nuclear stellar clusters. We focus on their secular evolution due to the perturbation by the MBHs, while simplistically accounting for their collisional evolution. Binaries with highly inclined orbits with respect to their orbits around MBHs are strongly affected by secular processes, which periodically change their eccentricities and inclinations (e.g., Kozai-Lidov cycles). During periapsis approach, dissipative processes such as tidal friction may become highly efficient, and may lead to shrinkage of a binary orbit and even to its merger. Binaries in this environment can therefore significantly change their orbital evolution due to the MBH third-body perturbative effects. Such orbital evolution may impinge on their later stellar evolution. Here we follow the secular dynamics of such binaries and its coupling to tidal evolution, as well as the stellar evolution of such binaries on longer timescales. We find that stellar binaries in the central parts of nuclear stellar clusters (NSCs) are highly likely to evolve into eccentric and/or short-period binaries, and become strongly interacting binaries either on the main sequence (at which point they may even merge), or through their later binary stellar evolution. The central parts of NSCs therefore catalyze the formation and evolution of strongly interacting binaries, and lead to the enhanced formation of blue stragglers, X-ray binaries, gravitational wave sources, and possible supernova progenitors. Induced mergers/collisions may also lead to the formation of G2-like cloud-like objects such as the one recently observed in the Galactic center

  11. Examining the Center: Positions, Dominance, and Star Formation Rates of Most Massive Group Galaxies at Intermediate Redshift

    Science.gov (United States)

    Connelly, Jennifer L.; Parker, Laura C.; McGee, Sean; Mulchaey, John S.; Finoguenov, Alexis; Balogh, Michael; Wilman, David; Group Environment Evolution Collaboration

    2015-01-01

    The group environment is believed to be the stage for many galaxy transformations, helping evolve blue star-forming galaxies to red passive ones. In local studies of galaxy clusters, the central member is usually a single dominant giant galaxy at the center of the potential with little star formation thought to be the result of galaxy mergers. In nearby groups, a range of morphologies and star formation rates are observed and the formation history is less clear. Further, the position and dominance of the central galaxy cannot be assumed in groups, which are less massive and evolved than clusters. To understand the connections between global group properties and properties of the central group galaxy at intermediate redshift, we examine galaxy groups from the Group Environment and Evolution Collaboration (GEEC) catalog, including both optically- and X-ray-selected groups at redshift z~0.4. The sample is diverse, containing a range in overall mass and evolutionary state. The number of groups is significant, membership is notably complete, and measurements span the IR to the UV allowing the properties of the members to be connected to those of the host groups. Having investigated trends in the global group properties previously, including mass and velocity substructure, we turn our attention now to the galaxy populations, focusing on the central regions of these systems. The most massive and second most massive group galaxies are identified by their stellar mass. The positions of the most massive galaxies (MMGs) are determined with respect to both the luminosity-weighted and X-ray center. Star formation rates are used to explore the fraction of passive/quiescent versus star-forming MMGs and the dominance of the MMGs in our group sample is also tested. Determinations of these characteristics and trends constitute the important first steps toward a detailed understanding of the relationships between the properties of host groups and their most massive galaxies and the

  12. Massive graviton geons

    Science.gov (United States)

    Aoki, Katsuki; Maeda, Kei-ichi; Misonoh, Yosuke; Okawa, Hirotada

    2018-02-01

    We find vacuum solutions such that massive gravitons are confined in a local spacetime region by their gravitational energy in asymptotically flat spacetimes in the context of the bigravity theory. We call such self-gravitating objects massive graviton geons. The basic equations can be reduced to the Schrödinger-Poisson equations with the tensor "wave function" in the Newtonian limit. We obtain a nonspherically symmetric solution with j =2 , ℓ=0 as well as a spherically symmetric solution with j =0 , ℓ=2 in this system where j is the total angular momentum quantum number and ℓ is the orbital angular momentum quantum number, respectively. The energy eigenvalue of the Schrödinger equation in the nonspherical solution is smaller than that in the spherical solution. We then study the perturbative stability of the spherical solution and find that there is an unstable mode in the quadrupole mode perturbations which may be interpreted as the transition mode to the nonspherical solution. The results suggest that the nonspherically symmetric solution is the ground state of the massive graviton geon. The massive graviton geons may decay in time due to emissions of gravitational waves but this timescale can be quite long when the massive gravitons are nonrelativistic and then the geons can be long-lived. We also argue possible prospects of the massive graviton geons: applications to the ultralight dark matter scenario, nonlinear (in)stability of the Minkowski spacetime, and a quantum transition of the spacetime.

  13. Molecular line study of massive star-forming regions from the Red MSX Source survey

    Science.gov (United States)

    Yu, Naiping; Wang, Jun-Jie

    2014-05-01

    In this paper, we have selected a sample of massive star-forming regions from the Red MSX Source survey, in order to study star formation activities (mainly outflow and inflow signatures). We have focused on three molecular lines from the Millimeter Astronomy Legacy Team Survey at 90 GHz: HCO+(1-0), H13CO+(1-0) and SiO(2-1). According to previous observations, our sources can be divided into two groups: nine massive young stellar object candidates (radio-quiet) and 10 H II regions (which have spherical or unresolved radio emissions). Outflow activities have been found in 11 sources, while only three show inflow signatures in all. The high outflow detection rate means that outflows are common in massive star-forming regions. The inflow detection rate was relatively low. We suggest that this was because of the beam dilution of the telescope. All three inflow candidates have outflow(s). The outward radiation and thermal pressure from the central massive star(s) do not seem to be strong enough to halt accretion in G345.0034-00.2240. Our simple model of G318.9480-00.1969 shows that it has an infall velocity of about 1.8 km s-1. The spectral energy distribution analysis agrees our sources are massive and intermediate-massive star formation regions.

  14. The central image of a gravitationally lensed quasar.

    Science.gov (United States)

    Winn, Joshua N; Rusin, David; Kochanek, Christopher S

    2004-02-12

    A galaxy can act as a gravitational lens, producing multiple images of a background object. Theory predicts that there should be an odd number of images produced by the lens, but hitherto almost all lensed objects have two or four images. The missing 'central' images, which should be faint and appear near the centre of the lensing galaxy, have long been sought as probes of galactic cores too distant to resolve with ordinary observations. There are five candidates for central images, but in one case the third image is not necessarily the central one, and in the others the putative central images might be foreground sources. Here we report a secure identification of a central image, based on radio observations of one of the candidates. Lens models using the central image reveal that the massive black hole at the centre of the lensing galaxy has a mass of 20,000M(o) pc(-2), which is in agreement with expections based on observations of galaxies that are much closer to the Earth.

  15. Population and Habitat Objectives for Avian Conservation in California's Central Valley Riparian Ecosystems

    Directory of Open Access Journals (Sweden)

    Kristen E. Dybala

    2017-03-01

    Full Text Available https://doi.org/10.15447/sfews.2017v15iss1art5Riparian ecosystems provide important ecosystem services and recreational opportunities for people, and habitat for wildlife. In California’s Central Valley, government agencies and private organizations are working together to protect and restore riparian ecosystems, and the Central Valley Joint Venture provides leadership in the formulation of goals and objectives for avian conservation in riparian ecosystems. We defined a long-term conservation goal as the establishment of riparian ecosystems that provide sufficient habitat to support genetically robust, self-sustaining, and resilient bird populations. To achieve this goal, we selected a suite of 12 breeding riparian landbird focal species as indicators of the state of riparian ecosystems in each of four major Central Valley planning regions. Using recent bird survey data, we estimated that over half of the regional focal species populations are currently small (< 10,000 and may be vulnerable to extirpation, and two species have steeply declining population trends. For each focal species in each region, we defined long-term (100-year population objectives that are intended to be conservation endpoints that we expect to meet the goal of genetically robust, self-sustaining, and resilient populations. We then estimated the long-term species density and riparian restoration objectives required to achieve the long-term population objectives. To track progress toward the long-term objectives, we propose short-term (10- year objectives, including the addition of 12,919 ha (31,923 ac of riparian vegetation in the Central Valley (by planning region: 3,390 ha in Sacramento, 2,390 ha in Yolo–Delta, 3,386 ha in San Joaquin, and 3,753 ha in Tulare. We expect that reaching these population, density, and habitat objectives through threat abatement, habitat restoration, and habitat enhancement will result in improvements to riparian ecosystem function and

  16. The Fate of Massive Black Holes in Gas-Rich Galaxy Mergers

    Science.gov (United States)

    Escala, A.; Larson, R. B.; Coppi, P. S.; Mardones, D.

    2006-06-01

    Using SPH numerical simulations, we investigate the effects of gas on the inspiral and merger of a massive black hole binary. This study is motivated by the very massive nuclear gas disks observed in the central regions of merging galaxies. Here we present results that expand on the treatment in previous works (Escala et al. 2004, 2005), by studying the evolution of a binary with different black holes masses in a massive gas disk.

  17. Upper Limits on the Presence of Central Massive Black Holes in Two Ultra-compact Dwarf Galaxies in Centaurus A

    Science.gov (United States)

    Voggel, Karina T.; Seth, Anil C.; Neumayer, Nadine; Mieske, Steffen; Chilingarian, Igor; Ahn, Christopher; Baumgardt, Holger; Hilker, Michael; Nguyen, Dieu D.; Romanowsky, Aaron J.; Walsh, Jonelle L.; den Brok, Mark; Strader, Jay

    2018-05-01

    The recent discovery of massive black holes (BHs) in the centers of high-mass ultra-compact dwarf galaxies (UCDs) suggests that at least some are the stripped nuclear star clusters of dwarf galaxies. We present the first study that investigates whether such massive BHs, and therefore stripped nuclei, also exist in low-mass (M < 107 M ⊙) UCDs. We constrain the BH masses of two UCDs located in Centaurus A (UCD 320 and UCD 330) using Jeans modeling of the resolved stellar kinematics from adaptive optics data obtained with the SINFONI integral field spectrograph at the Very Large Telescope (VLT/SINFONI). No massive BHs are found in either UCD. We find a 3σ upper limit on the central BH mass in UCD 330 of M • < 1.0 × 105 M ⊙, which corresponds to 1.7% of the total mass. This excludes a high-mass fraction BH and would only allow low-mass BHs similar to those claimed to be detected in Local Group globular clusters. For UCD 320, poorer data quality results in a less constraining 3σ upper limit of M • < 1 × 106 M ⊙, which is equal to 37.7% of the total mass. The dynamical mass-to-light ratios of UCD 320 and UCD 330 are not inflated compared to predictions from stellar population models. The non-detection of BHs in these low-mass UCDs is consistent with the idea that elevated dynamical mass-to-light ratios do indicate the presence of a substantial BH. Although no massive BHs are detected, these systems could still be stripped nuclei. The strong rotation (v/σ of 0.3–0.4) in both UCDs and the two-component light profile in UCD 330 support the idea that these UCDs may be stripped nuclei of low-mass galaxies whose BH occupation fraction is not yet known.

  18. Data Rods: High Speed, Time-Series Analysis of Massive Cryospheric Data Sets Using Object-Oriented Database Methods

    Science.gov (United States)

    Liang, Y.; Gallaher, D. W.; Grant, G.; Lv, Q.

    2011-12-01

    Change over time, is the central driver of climate change detection. The goal is to diagnose the underlying causes, and make projections into the future. In an effort to optimize this process we have developed the Data Rod model, an object-oriented approach that provides the ability to query grid cell changes and their relationships to neighboring grid cells through time. The time series data is organized in time-centric structures called "data rods." A single data rod can be pictured as the multi-spectral data history at one grid cell: a vertical column of data through time. This resolves the long-standing problem of managing time-series data and opens new possibilities for temporal data analysis. This structure enables rapid time- centric analysis at any grid cell across multiple sensors and satellite platforms. Collections of data rods can be spatially and temporally filtered, statistically analyzed, and aggregated for use with pattern matching algorithms. Likewise, individual image pixels can be extracted to generate multi-spectral imagery at any spatial and temporal location. The Data Rods project has created a series of prototype databases to store and analyze massive datasets containing multi-modality remote sensing data. Using object-oriented technology, this method overcomes the operational limitations of traditional relational databases. To demonstrate the speed and efficiency of time-centric analysis using the Data Rods model, we have developed a sea ice detection algorithm. This application determines the concentration of sea ice in a small spatial region across a long temporal window. If performed using traditional analytical techniques, this task would typically require extensive data downloads and spatial filtering. Using Data Rods databases, the exact spatio-temporal data set is immediately available No extraneous data is downloaded, and all selected data querying occurs transparently on the server side. Moreover, fundamental statistical

  19. Radiative transfer modelling of W33A MM1: 3-D structure and dynamics of a complex massive star forming region

    Science.gov (United States)

    Izquierdo, Andrés F.; Galván-Madrid, Roberto; Maud, Luke T.; Hoare, Melvin G.; Johnston, Katharine G.; Keto, Eric R.; Zhang, Qizhou; de Wit, Willem-Jan

    2018-05-01

    We present a composite model and radiative transfer simulations of the massive star forming core W33A MM1. The model was tailored to reproduce the complex features observed with ALMA at ≈0.2 arcsec resolution in CH3CN and dust emission. The MM1 core is fragmented into six compact sources coexisting within ˜1000 au. In our models, three of these compact sources are better represented as disc-envelope systems around a central (proto)star, two as envelopes with a central object, and one as a pure envelope. The model of the most prominent object (Main) contains the most massive (proto)star (M⋆ ≈ 7 M⊙) and disc+envelope (Mgas ≈ 0.4 M⊙), and is the most luminous (LMain ˜ 104 L⊙). The model discs are small (a few hundred au) for all sources. The composite model shows that the elongated spiral-like feature converging to the MM1 core can be convincingly interpreted as a filamentary accretion flow that feeds the rising stellar system. The kinematics of this filament is reproduced by a parabolic trajectory with focus at the center of mass of the region. Radial collapse and fragmentation within this filament, as well as smaller filamentary flows between pairs of sources are proposed to exist. Our modelling supports an interpretation where what was once considered as a single massive star with a ˜103 au disc and envelope, is instead a forming stellar association which appears to be virialized and to form several low-mass stars per high-mass object.

  20. Massive Splenomegaly in Children: Laparoscopic Versus Open Splenectomy

    OpenAIRE

    Hassan, Mohamed E.; Al Ali, Khalid

    2014-01-01

    Background and Objectives: Laparoscopic splenectomy for massive splenomegaly is still a controversial procedure as compared with open splenectomy. We aimed to compare the feasibility of laparoscopic splenectomy versus open splenectomy for massive splenomegaly from different surgical aspects in children. Methods: The data of children aged

  1. Dynamics of massive black holes as a possible candidate of Galactic dark matter

    Science.gov (United States)

    Xu, Guohong; Ostriker, Jeremiah P.

    1994-01-01

    If the dark halo of the Galaxy is comprised of massive black holes (MBHs), then those within approximately 1 kpc will spiral to the center, where they will interact with one another, forming binaries which contract, owing to further dynamical friction, and then possibly merge to become more massive objects by emission of gravitational radiation. If successive mergers would invariably lead, as has been proposed by various authors, to the formation of a very massive nucleus of 10(exp 8) solar mass, then the idea of MBHs as a dark matter candidate could be excluded on observational grounds, since the observed limit (or value) for a Galactic central black hole is approximately 10(exp 6.5) solar mass. But, if successive mergers are delayed or prevented by other processes, such as the gravitational slingshot or rocket effect of gravitational radiation, then a large mass accumulation will not occur. In order to resolve this issue, we perform detailed N-body simulations using a modfied Aarseth code to explore the dynamical behavior of the MBHs, and we find that for a 'best estimate' model of the Galaxy a runaway does not occur. The code treates the MBHs as subject to the primary gravitational forces of one another and to the smooth stellar distribution, as well as the secondary perturbations in their orbits due to another and to the smooth stellar distribution, as well as the secondary perturbations in their orbits due to dynamical friction and gravitational radiation. Instead of a runaway, three-body interactions between hard binaries and single MBHs eject massive objects before accumulation of more than a few units, so that typically the center will contain zero, one, or two MBHs. We study how the situation depends in detail on the mass per MBH, the rotation of the halo, the mass distribution within the Galaxy, and other parameters. A runaway will most sensitively depend on the ratio of initial (spheroid/halo) central mass densities and secondarily on the typical values

  2. Population and Habitat Objectives for Breeding Shorebirds in California’s Central Valley

    Directory of Open Access Journals (Sweden)

    Khara M. Strum

    2017-03-01

    Full Text Available http://escholarship.org/uc/item/2836q0qgThe Central Valley of California provides important breeding habitat to numerous species of wetland-dependent birds, despite the loss of over 90% of naturally occurring wetlands. A majority of shorebirds breeding in this region rely on shallow-flooded habitat adjacent to sparsely vegetated uplands as provided by rice (Oryza sativa, managed wetlands, and other habitats. We estimated the current extent of potential breeding shorebird habitat provided by rice and managed permanent and semi-permanent wetlands in each of four major planning regions of the Central Valley, and estimated the average breeding densities and current population sizes of two species of shorebirds: the Black-Necked Stilt (Himantopus mexicanus and American Avocet (Recurvirostra americana. Using a population status framework based on principles of conservation biology, we estimated that stilt populations are small (<10,000 individuals or very small (<1,000 individuals in three of the four planning regions, and avocet populations are small or very small in all four planning regions. We then used the framework to define long-term (100-year population objectives for stilts, avocets, and a third species, Killdeer (Charadrius vociferous, designed to meet our long-term conservation goal of supporting self-sustaining, genetically robust, and resilient populations of breeding shorebirds in the Central Valley. We also estimated the long-term species’ density and wetland habitat objectives necessary to achieve the population objectives for all three species. The corresponding short-term (10-year conservation objectives are to restore semi-permanent wetlands to provide an additional 11,537 ha (28,508 ac of habitat for breeding shorebirds (by planning region: 2,842 ha in Sacramento, 2,897 ha in Yolo–Delta, 2,943 ha in San Joaquin, and 2,855 ha in Tulare, and to enhance existing habitat to support density objectives. Our approach provides a

  3. X-RAY AND RADIO OBSERVATIONS OF THE MASSIVE STAR-FORMING REGION IRAS 20126+4104

    Energy Technology Data Exchange (ETDEWEB)

    Montes, V. A.; Hofner, P.; Anderson, C.; Rosero, V. [Physics Department, New Mexico Tech, 801 Leroy Place, Socorro, NM 87801 (United States)

    2015-08-15

    We present results from Chandra ACIS-I and Karl G. Jansky Very Large Array 6 cm continuum observations of the IRAS 20126+4104 massive star-forming region. We detect 150 X-ray sources within the 17′ × 17′ ACIS-I field, and a total of 13 radio sources within the 9.′2 primary beam at 4.9 GHz. Among these observtions are the first 6 cm detections of the central sources reported by Hofner et al., namely, I20N1, I20S, and I20var. A new variable radio source is also reported. Searching the 2MASS archive, we identified 88 near-infrared (NIR) counterparts to the X-ray sources. Only four of the X-ray sources had 6 cm counterparts. Based on an NIR color–color analysis and on the Besançon simulation of Galactic stellar populations, we estimate that approximately 80 X-ray sources are associated with this massive star-forming region. We detect an increasing surface density of X-ray sources toward the massive protostar and infer the presence of a cluster of at least 43 young stellar objects within a distance of 1.2 pc from the massive protostar.

  4. The dynamical fingerprint of core scouring in massive elliptical galaxies

    International Nuclear Information System (INIS)

    Thomas, J.; Saglia, R. P.; Bender, R.; Erwin, P.; Fabricius, M.

    2014-01-01

    The most massive elliptical galaxies have low-density centers or cores that differ dramatically from the high-density centers of less massive ellipticals and bulges of disk galaxies. These cores have been interpreted as the result of mergers of supermassive black hole binaries, which depopulate galaxy centers by gravitationally slingshotting central stars toward large radii. Such binaries naturally form in mergers of luminous galaxies. Here, we analyze the population of central stellar orbits in 11 massive elliptical galaxies that we observed with the integral field spectrograph SINFONI at the European Southern Observatory Very Large Telescope. Our dynamical analysis is orbit-based and includes the effects of a central black hole, the mass distribution of the stars, and a dark matter halo. We show that the use of integral field kinematics and the inclusion of dark matter is important to conclude on the distribution of stellar orbits in galaxy centers. Six of our galaxies are core galaxies. In these six galaxies, but not in the galaxies without cores, we detect a coherent lack of stars on radial orbits in the core region and a uniform excess of radial orbits outside of it: when scaled by the core radius r b , the radial profiles of the classical anisotropy parameter β(r) are nearly identical in core galaxies. Moreover, they quantitatively match the predictions of black hole binary simulations, providing the first convincing dynamical evidence for core scouring in the most massive elliptical galaxies.

  5. The efficiency of seismic attributes to differentiate between massive and non-massive carbonate successions for hydrocarbon exploration activity

    Science.gov (United States)

    Sarhan, Mohammad Abdelfattah

    2017-12-01

    The present work investigates the efficiency of applying volume seismic attributes to differentiate between massive and non-massive carbonate sedimentary successions on using seismic data. The main objective of this work is to provide a pre-drilling technique to recognize the porous carbonate section (probable hydrocarbon reservoirs) based on seismic data. A case study from the Upper Cretaceous - Eocene carbonate successions of Abu Gharadig Basin, northern Western Desert of Egypt has been tested in this work. The qualitative interpretations of the well-log data of four available wells distributed in the study area, namely; AG-2, AG-5, AG-6 and AG-15 wells, has confirmed that the Upper Cretaceous Khoman A Member represents the massive carbonate section whereas the Eocene Apollonia Formation represents the non-massive carbonate unit. The present work have proved that the most promising seismic attributes capable of differentiating between massive and non-massive carbonate sequences are; Root Mean Square (RMS) Amplitude, Envelope (Reflection Strength), Instantaneous Frequency, Chaos, Local Flatness and Relative Acoustic Impedance.

  6. Black-hole-regulated star formation in massive galaxies

    Science.gov (United States)

    Martín-Navarro, Ignacio; Brodie, Jean P.; Romanowsky, Aaron J.; Ruiz-Lara, Tomás; van de Ven, Glenn

    2018-01-01

    Supermassive black holes, with masses more than a million times that of the Sun, seem to inhabit the centres of all massive galaxies. Cosmologically motivated theories of galaxy formation require feedback from these supermassive black holes to regulate star formation. In the absence of such feedback, state-of-the-art numerical simulations fail to reproduce the number density and properties of massive galaxies in the local Universe. There is, however, no observational evidence of this strongly coupled coevolution between supermassive black holes and star formation, impeding our understanding of baryonic processes within galaxies. Here we report that the star formation histories of nearby massive galaxies, as measured from their integrated optical spectra, depend on the mass of the central supermassive black hole. Our results indicate that the black-hole mass scales with the gas cooling rate in the early Universe. The subsequent quenching of star formation takes place earlier and more efficiently in galaxies that host higher-mass central black holes. The observed relation between black-hole mass and star formation efficiency applies to all generations of stars formed throughout the life of a galaxy, revealing a continuous interplay between black-hole activity and baryon cooling.

  7. Black-hole-regulated star formation in massive galaxies.

    Science.gov (United States)

    Martín-Navarro, Ignacio; Brodie, Jean P; Romanowsky, Aaron J; Ruiz-Lara, Tomás; van de Ven, Glenn

    2018-01-18

    Supermassive black holes, with masses more than a million times that of the Sun, seem to inhabit the centres of all massive galaxies. Cosmologically motivated theories of galaxy formation require feedback from these supermassive black holes to regulate star formation. In the absence of such feedback, state-of-the-art numerical simulations fail to reproduce the number density and properties of massive galaxies in the local Universe. There is, however, no observational evidence of this strongly coupled coevolution between supermassive black holes and star formation, impeding our understanding of baryonic processes within galaxies. Here we report that the star formation histories of nearby massive galaxies, as measured from their integrated optical spectra, depend on the mass of the central supermassive black hole. Our results indicate that the black-hole mass scales with the gas cooling rate in the early Universe. The subsequent quenching of star formation takes place earlier and more efficiently in galaxies that host higher-mass central black holes. The observed relation between black-hole mass and star formation efficiency applies to all generations of stars formed throughout the life of a galaxy, revealing a continuous interplay between black-hole activity and baryon cooling.

  8. Formation of massive seed black holes via collisions and accretion

    Science.gov (United States)

    Boekholt, T. C. N.; Schleicher, D. R. G.; Fellhauer, M.; Klessen, R. S.; Reinoso, B.; Stutz, A. M.; Haemmerlé, L.

    2018-05-01

    Models aiming to explain the formation of massive black hole seeds, and in particular the direct collapse scenario, face substantial difficulties. These are rooted in rather ad hoc and fine-tuned initial conditions, such as the simultaneous requirements of extremely low metallicities and strong radiation backgrounds. Here, we explore a modification of such scenarios where a massive primordial star cluster is initially produced. Subsequent stellar collisions give rise to the formation of massive (104-105 M⊙) objects. Our calculations demonstrate that the interplay among stellar dynamics, gas accretion, and protostellar evolution is particularly relevant. Gas accretion on to the protostars enhances their radii, resulting in an enhanced collisional cross-section. We show that the fraction of collisions can increase from 0.1 to 1 per cent of the initial population to about 10 per cent when compared to gas-free models or models of protostellar clusters in the local Universe. We conclude that very massive objects can form in spite of initial fragmentation, making the first massive protostellar clusters viable candidate birth places for observed supermassive black holes.

  9. Conservation Objectives for Wintering and Breeding Waterbirds in California’s Central Valley

    Directory of Open Access Journals (Sweden)

    W. David Shuford

    2017-03-01

    Full Text Available http://escholarship.org/uc/item/5tp5m718Birds associated with wetlands have declined historically across North America from extensive habitat loss and degradation. Among the regions most affected is California’s Central Valley, where over 90% of the wetland base has been lost. Still, this region remains of continental importance to waterbirds. On-the-ground conservation efforts for all bird groups are the focus of the Central Valley Joint Venture, guided by a periodically updated implementation plan. To track progress toward goal attainment, that plan sets time-bound, quantitative conservation goals. Lacking robust data on the size and trends of populations of most species of waterbirds in the Central Valley, we set conservation goals for this group by selecting 10 focal species. These species are of heightened conservation concern or are otherwise representative of the habitat needs of Central Valley waterbirds. Given the great loss of historical habitat, we assumed focal species populations have declined by ≥ 50%. Hence, we defined population objectives for most focal species as increasing their current populations by 10% over 10 years and doubling them in 100 years. The corresponding habitat objectives are to increase wetlands or enhance suitable crops for waterbirds in proportion to the population objectives. These include an increase over 10 years of 7,948 ha (19,641 acres of winter seasonal wetlands, 921 ha (2,276 acres each of semi-permanent and summer seasonal wetlands, and 573 ha (1,416 acres of strategically placed riparian forest. Agricultural needs include additional winter flooding of 15,160 ha (37,461 acres of rice and 2,137 ha (5,281 acres of corn. We distributed the habitat objectives across five planning regions, in some cases favoring proportionally larger increases in those regions with the greatest need. To maximize success, however, conservationists must take into account the specific needs of individual waterbird

  10. YOUNG STELLAR CLUSTERS CONTAINING MASSIVE YOUNG STELLAR OBJECTS IN THE VVV SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Borissova, J.; Alegría, S. Ramírez; Kurtev, R.; Medina, N.; Navarro, C.; Kuhn, M.; Gromadzki, M.; Retamales, G.; Fernandez, M. A.; Agurto-Gangas, C.; Amigo, P. [Instituto de Física y Astronomía, Universidad de Valparaíso, Av. Gran Bretaña 1111, Playa Ancha, Casilla 5030 (Chile); Alonso, J.; Decany, I. [Millennium Institute of Astrophysics (MAS), Santiago (Chile); Lucas, P. W.; Pena, C. Contreras; Thompson, M. A. [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Chené, A.-N. [Gemini Observatory, Northern Operations Center, 670 N. A’ohoku Place, Hilo, HI 96720 (United States); Minniti, D. [Departamento de Ciencias Físicas, Universidad Andres Bello, Republica 220, Santiago (Chile); Catelan, M. [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile); Morales, E. F. E., E-mail: jura.borissova@uv.cl [Max-Planck-Institute for Astronomy (Germany)

    2016-09-01

    The purpose of this research is to study the connections of the global properties of eight young stellar clusters projected in the Vista Variables in the Via Lactea (VVV) ESO Large Public Survey disk area and their young stellar object (YSO) populations. The analysis is based on the combination of spectroscopic parallax-based reddening and distance determinations with main-sequence and pre-main-sequence ishochrone fitting to determine the basic parameters (reddening, age, distance) of the sample clusters. The lower mass limit estimations show that all clusters are low or intermediate mass (between 110 and 1800  M {sub ⊙}), the slope Γ of the obtained present-day mass functions of the clusters is close to the Kroupa initial mass function. The YSOs in the cluster’s surrounding fields are classified using low resolution spectra, spectral energy distribution fits with theoretical predictions, and variability, taking advantage of multi-epoch VVV observations. All spectroscopically confirmed YSOs (except one) are found to be massive (more than 8 M {sub ⊙}). Using VVV and GLIMPSE color–color cuts we have selected a large number of new YSO candidates, which are checked for variability and 57% are found to show at least low-amplitude variations. In few cases it was possible to distinguish between YSO and AGB classifications on the basis of light curves.

  11. Massive (p,q)-supersymmetric sigma models revisited

    International Nuclear Information System (INIS)

    Papadopoulos, G.

    1994-06-01

    We recently obtained the conditions on the couplings of the general two-dimensional massive sigma-model required by (p,q)-supersymmetry. Here wer compute the Poisson bracket algebra of the supersymmetry and central Noether charges, and show that the action is invariant under the automorphism group of this algebra. Surprisingly, for the (4,4) case the automorphism group is always a subgroup of SO(3), rather than SO(4). We also re-analyse the conditions for (2,2) and 4,4) supersymmetry of the zero torsion models without assumptions about the central charge matrix. (orig.)

  12. EARLY-STAGE MASSIVE STAR FORMATION NEAR THE GALACTIC CENTER: Sgr C

    Energy Technology Data Exchange (ETDEWEB)

    Kendrew, S.; Johnston, K.; Beuther, H. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Ginsburg, A.; Bally, J.; Battersby, C. [CASA, University of Colorado at Boulder, UCB 389, Boulder, CO 80309 (United States); Cyganowski, C. J., E-mail: kendrew@mpia.de [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

    2013-10-01

    We present near-infrared spectroscopy and 1 mm line and continuum observations of a recently identified site of high mass star formation likely to be located in the Central Molecular Zone (CMZ) near Sgr C. Located on the outskirts of the massive evolved H II region associated with Sgr C, the area is characterized by an Extended Green Object (EGO) measuring ∼10'' in size (0.4 pc), whose observational characteristics suggest the presence of an embedded massive protostar driving an outflow. Our data confirm that early-stage star formation is taking place on the periphery of the Sgr C H II region, with detections of two protostellar cores and several knots of H{sub 2} and Brackett γ emission alongside a previously detected compact radio source. We calculate the cores' joint mass to be ∼10{sup 3} M {sub ☉}, with column densities of 1-2 × 10{sup 24} cm{sup –2}. We show the host molecular cloud to hold ∼10{sup 5} M {sub ☉} of gas and dust with temperatures and column densities favorable for massive star formation to occur, however, there is no evidence of star formation outside of the EGO, indicating that the cloud is predominantly quiescent. Given its mass, density, and temperature, the cloud is comparable to other remarkable non-star-forming clouds such as G0.253 in the eastern CMZ.

  13. Spin-3 topologically massive gravity

    Energy Technology Data Exchange (ETDEWEB)

    Chen Bin, E-mail: bchen01@pku.edu.cn [Department of Physics, and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Center for High Energy Physics, Peking University, Beijing 100871 (China); Long Jiang, E-mail: longjiang0301@gmail.com [Department of Physics, and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Wu Junbao, E-mail: wujb@ihep.ac.cn [Institute of High Energy Physics, and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing 100049 (China)

    2011-11-24

    In this Letter, we study the spin-3 topologically massive gravity (TMG), paying special attention to its properties at the chiral point. We propose an action describing the higher spin fields coupled to TMG. We discuss the traceless spin-3 fluctuations around the AdS{sub 3} vacuum and find that there is an extra local massive mode, besides the left-moving and right-moving boundary massless modes. At the chiral point, such extra mode becomes massless and degenerates with the left-moving mode. We show that at the chiral point the only degrees of freedom in the theory are the boundary right-moving graviton and spin-3 field. We conjecture that spin-3 chiral gravity with generalized Brown-Henneaux boundary condition is holographically dual to 2D chiral CFT with classical W{sub 3} algebra and central charge c{sub R}=3l/G.

  14. Neutron stars structure in the context of massive gravity

    Energy Technology Data Exchange (ETDEWEB)

    Hendi, S.H.; Bordbar, G.H.; Panah, B. Eslam; Panahiyan, S., E-mail: hendi@shirazu.ac.ir, E-mail: ghbordbar@shirazu.ac.ir, E-mail: behzad.eslampanah@gmail.com, E-mail: sh.panahiyan@gmail.com [Physics Department and Biruni Observatory, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of)

    2017-07-01

    Motivated by the recent interests in spin−2 massive gravitons, we study the structure of neutron star in the context of massive gravity. The modifications of TOV equation in the presence of massive gravity are explored in 4 and higher dimensions. Next, by considering the modern equation of state for the neutron star matter (which is extracted by the lowest order constrained variational (LOCV) method with the AV18 potential), different physical properties of the neutron star (such as Le Chatelier's principle, stability and energy conditions) are investigated. It is shown that consideration of the massive gravity has specific contributions into the structure of neutron star and introduces new prescriptions for the massive astrophysical objects. The mass-radius relation is examined and the effects of massive gravity on the Schwarzschild radius, average density, compactness, gravitational redshift and dynamical stability are studied. Finally, a relation between mass and radius of neutron star versus the Planck mass is extracted.

  15. Neutron stars structure in the context of massive gravity

    Science.gov (United States)

    Hendi, S. H.; Bordbar, G. H.; Eslam Panah, B.; Panahiyan, S.

    2017-07-01

    Motivated by the recent interests in spin-2 massive gravitons, we study the structure of neutron star in the context of massive gravity. The modifications of TOV equation in the presence of massive gravity are explored in 4 and higher dimensions. Next, by considering the modern equation of state for the neutron star matter (which is extracted by the lowest order constrained variational (LOCV) method with the AV18 potential), different physical properties of the neutron star (such as Le Chatelier's principle, stability and energy conditions) are investigated. It is shown that consideration of the massive gravity has specific contributions into the structure of neutron star and introduces new prescriptions for the massive astrophysical objects. The mass-radius relation is examined and the effects of massive gravity on the Schwarzschild radius, average density, compactness, gravitational redshift and dynamical stability are studied. Finally, a relation between mass and radius of neutron star versus the Planck mass is extracted.

  16. Neutron stars structure in the context of massive gravity

    International Nuclear Information System (INIS)

    Hendi, S.H.; Bordbar, G.H.; Panah, B. Eslam; Panahiyan, S.

    2017-01-01

    Motivated by the recent interests in spin−2 massive gravitons, we study the structure of neutron star in the context of massive gravity. The modifications of TOV equation in the presence of massive gravity are explored in 4 and higher dimensions. Next, by considering the modern equation of state for the neutron star matter (which is extracted by the lowest order constrained variational (LOCV) method with the AV18 potential), different physical properties of the neutron star (such as Le Chatelier's principle, stability and energy conditions) are investigated. It is shown that consideration of the massive gravity has specific contributions into the structure of neutron star and introduces new prescriptions for the massive astrophysical objects. The mass-radius relation is examined and the effects of massive gravity on the Schwarzschild radius, average density, compactness, gravitational redshift and dynamical stability are studied. Finally, a relation between mass and radius of neutron star versus the Planck mass is extracted.

  17. Population and Habitat Objectives for Avian Conservation in California’s Central Valley Grassland–Oak Savannah Ecosystems

    Directory of Open Access Journals (Sweden)

    Ryan T. DiGaudio

    2017-03-01

    Full Text Available http://escholarship.org/uc/item/0dn9f9b4In California’s Central Valley, grassland and oak savannah ecosystems provide multiple economic and social benefits, ecosystem services, and vital bird habitat. There is a growing interest in protecting, restoring, and managing these ecosystems, and the Central Valley Joint Venture (CVJV provides leadership in the formulation of conservation goals and objectives. We defined a long-term goal of protecting, restoring, and managing Central Valley grassland and oak savannah ecosystems so that they are capable of supporting genetically robust, self-sustaining, and resilient wildlife populations. To measure progress toward this goal, we selected a suite of 12 landbird focal species that primarily breed in grasslands and oak savannahs as indicators of the state of these ecosystems on the Central Valley floor (primary focus area and in the Central Valley’s surrounding foothills (secondary focus area. Using data on current densities and habitat extent, we estimated that at least three of the focal species populations in the primary focus area and at least two of the focal species populations in the secondary focus area are currently small (<10,000 individuals and may be vulnerable to extirpation. Furthermore, at least two species appear to have steeply declining population trends. We defined long-term (100-year population objectives for each focal species that we expect to meet the goal of genetically robust, self-sustaining, and resilient populations. We then estimated corresponding short-term (10-year habitat objectives of 4,183 ha of additional grassland and 3,433 ha of additional oak savannah that will be required to make progress toward the long-term objectives. We expect that habitat restoration and enhancement efforts aimed at reaching these long-term conservation objectives will result in improvements to the function of Central Valley grassland and oak savannah ecosystems.

  18. Magnetic fields and massive star formation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qizhou; Keto, Eric; Ho, Paul T. P.; Ching, Tao-Chung; Chen, How-Huan [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Qiu, Keping [School of Astronomy and Space Science, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Girart, Josep M.; Juárez, Carmen [Institut de Ciències de l' Espai, (CSIC-IEEC), Campus UAB, Facultat de Ciències, C5p 2, E-08193 Bellaterra, Catalonia (Spain); Liu, Hauyu; Tang, Ya-Wen; Koch, Patrick M.; Rao, Ramprasad; Lai, Shih-Ping [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan (China); Li, Zhi-Yun [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States); Frau, Pau [Observatorio Astronómico Nacional, Alfonso XII, 3 E-28014 Madrid (Spain); Li, Hua-Bai [Department of Physics, The Chinese University of Hong Kong, Hong Kong (China); Padovani, Marco [Laboratoire de Radioastronomie Millimétrique, UMR 8112 du CNRS, École Normale Supérieure et Observatoire de Paris, 24 rue Lhomond, F-75231 Paris Cedex 05 (France); Bontemps, Sylvain [OASU/LAB-UMR5804, CNRS, Université Bordeaux 1, F-33270 Floirac (France); Csengeri, Timea, E-mail: qzhang@cfa.harvard.edu [Max Planck Institute for Radioastronomy, Auf dem Hügel 69, D-53121 Bonn (Germany)

    2014-09-10

    Massive stars (M > 8 M {sub ☉}) typically form in parsec-scale molecular clumps that collapse and fragment, leading to the birth of a cluster of stellar objects. We investigate the role of magnetic fields in this process through dust polarization at 870 μm obtained with the Submillimeter Array (SMA). The SMA observations reveal polarization at scales of ≲0.1 pc. The polarization pattern in these objects ranges from ordered hour-glass configurations to more chaotic distributions. By comparing the SMA data with the single dish data at parsec scales, we found that magnetic fields at dense core scales are either aligned within 40° of or perpendicular to the parsec-scale magnetic fields. This finding indicates that magnetic fields play an important role during the collapse and fragmentation of massive molecular clumps and the formation of dense cores. We further compare magnetic fields in dense cores with the major axis of molecular outflows. Despite a limited number of outflows, we found that the outflow axis appears to be randomly oriented with respect to the magnetic field in the core. This result suggests that at the scale of accretion disks (≲ 10{sup 3} AU), angular momentum and dynamic interactions possibly due to close binary or multiple systems dominate over magnetic fields. With this unprecedentedly large sample of massive clumps, we argue on a statistical basis that magnetic fields play an important role during the formation of dense cores at spatial scales of 0.01-0.1 pc in the context of massive star and cluster star formation.

  19. Where Have All the Central Compact Objects Gone?

    Science.gov (United States)

    Gotthelf, Eric

    2017-09-01

    The central compact object (CCO) class of young neutron stars in supernova remnants (SNRs) are detected only as thermal X-ray sources. Characterized by weak magnetic fields, a fundamental puzzle of their evolution is the absence of any evidence for their numerous descendants in X-ray or radio surveys. We know that their true ages are much younger than their inferred timing ages, which implies that some apparently old radio pulsars may actually be evolved CCOs in dispersed SNRs, young enough to be detected as still hot thermal X-ray sources. Here we propose a complete volume limited survey of apparently old radio pulsars to search for descendants of CCOs, providing important constraints on neutron star evolution.

  20. One of the most massive stars in the Galaxy may have formed in isolation

    OpenAIRE

    Oskinova, L. M.; Steinke, M.; Hamann, W. -R.; Sander, A.; Todt, H.; Liermann, A.

    2013-01-01

    Very massive stars, 100 times heavier than the sun, are rare. It is not yet known whether such stars can form in isolation or only in star clusters. The answer to this question is of fundamental importance. The central region of our Galaxy is ideal for investigating very massive stars and clusters located in the same environment. We used archival infrared images to investigate the surroundings of apparently isolated massive stars presently known in the Galactic Center. We find that two such i...

  1. Collisions Between Single Stars in Dense Clusters: Runaway Formation of a Massive Object

    NARCIS (Netherlands)

    Freitag, M.; Gürkan, M.A.; Rasio, F.A.

    2007-01-01

    Using Monte Carlo codes, we follow the collisional evolution of clusters in a variety of scenarios. We consider the conditions under which a cluster of main-sequence stars may undergo rapid core collapse due to mass segregation, thus entering a phase of runaway collisions, forming a very massive

  2. HII regions in collapsing massive molecular clouds

    International Nuclear Information System (INIS)

    Yorke, H.W.; Bodenheimer, P.; Tenorio-Tagle, G.

    1982-01-01

    Results of two-dimensional numerical calculations of the evolution of HII regions associated with self-gravitating, massive molecular clouds are presented. Depending on the location of the exciting star, a champagne flow can occur concurrently with the central collapse of a nonrotating cloud. Partial evaporation of the cloud at a rate of about 0.005 solar masses/yr results. When 100 O-stars are placed at the center of a freely falling cloud of 3x10 5 solar masses no evaporation takes place. Rotating clouds collapse to disks and the champagne flow can evaporate the cloud at a higher rate (0.01 solar masses/yr). It is concluded that massive clouds containing OB-stars have lifetimes of no more than 10 7 yr. (Auth.)

  3. A Massive Star Census of the Starburst Cluster R136

    Science.gov (United States)

    Crowther, Paul

    2012-10-01

    We propose to carry out a comprehensive census of the most massive stars in the central parsec {4"} of the starburst cluster, R136, which powers the Tarantula Nebula in the LMC. R136 is both sufficiently massive that the upper mass function is richly populated and young enough that its most massive stars have yet to explode as supernovae. The identification of very massive stars in R136, up to 300 solar masses, raises general questions of star formation, binarity and feedback in young massive clusters. The proposed STIS spectral survey of 36 stars more massive than 50 solar masses within R136 is ground-breaking, of legacy value, and is specifically tailored to a} yield physical properties; b} detect the majority of binaries by splitting observations between Cycles 19 and 20; c} measure rotational velocities, relevant for predictions of rotational mixing; d} quantify mass-loss properties for very massive stars; e} determine surface compositions; f} measure radial velocities, relevant for runaway stars and cluster dynamics; g} quantify radiative and mechanical feedback. This census will enable the mass function of very massive stars to be measured for the first time, as a result of incomplete and inadequate spectroscopy to date. It will also perfectly complement our Tarantula Survey, a ground-based VLT Large Programme, by including the most massive stars that are inaccessible to ground-based visual spectroscopy due to severe crowding. These surveys, together with existing integrated UV and optical studies will enable 30 Doradus to serve as a bona-fide template for unresolved extragalactic starburst regions.

  4. A dearth of short-period massive binaries in the young massive star forming region M 17. Evidence for a large orbital separation at birth?

    Science.gov (United States)

    Sana, H.; Ramírez-Tannus, M. C.; de Koter, A.; Kaper, L.; Tramper, F.; Bik, A.

    2017-03-01

    Aims: The formation of massive stars remains poorly understood and little is known about their birth multiplicity properties. Here, we aim to quantitatively investigate the strikingly low radial-velocity dispersion measured for a sample of 11 massive pre- and near-main-sequence stars (σ1D= 5.6 ± 0.2 km s-1) in the very young massive star forming region M 17, in order to obtain first constraints on the multiplicity properties of young massive stellar objects. Methods: We compute the radial-velocity dispersion of synthetic populations of massive stars for various multiplicity properties and we compare the obtained σ1D distributions to the observed value. We specifically investigate two scenarios: a low binary fraction and a dearth of short-period binary systems. Results: Simulated populations with low binary fractions () or with truncated period distributions (Pcutoff > 9 months) are able to reproduce the low σ1D observed within their 68%-confidence intervals. Furthermore, parent populations with fbin > 0.42 or Pcutoff < 47 d can be rejected at the 5%-significance level. Both constraints are in stark contrast with the high binary fraction and plethora of short-period systems in few Myr-old, well characterized OB-type populations. To explain the difference in the context of the first scenario would require a variation of the outcome of the massive star formation process. In the context of the second scenario, compact binaries must form later on, and the cut-off period may be related to physical length-scales representative of the bloated pre-main-sequence stellar radii or of their accretion disks. Conclusions: If the obtained constraints for the M 17's massive-star population are representative of the multiplicity properties of massive young stellar objects, our results may provide support to a massive star formation process in which binaries are initially formed at larger separations, then harden or migrate to produce the typical (untruncated) power-law period

  5. Massive branes

    International Nuclear Information System (INIS)

    Bergshoeff, E.; Ortin, T.

    1998-01-01

    We investigate the effective world-volume theories of branes in a background given by (the bosonic sector of) 10-dimensional massive IIA supergravity (''''massive branes'''') and their M-theoretic origin. In the case of the solitonic 5-brane of type IIA superstring theory the construction of the Wess-Zumino term in the world-volume action requires a dualization of the massive Neveu-Schwarz/Neveu-Schwarz target space 2-form field. We find that, in general, the effective world-volume theory of massive branes contains new world-volume fields that are absent in the massless case, i.e. when the mass parameter m of massive IIA supergravity is set to zero. We show how these new world-volume fields can be introduced in a systematic way. (orig.)

  6. LiNbO3: A photovoltaic substrate for massive parallel manipulation and patterning of nano-objects

    International Nuclear Information System (INIS)

    Carrascosa, M.; García-Cabañes, A.; Jubera, M.; Ramiro, J. B.; Agulló-López, F.

    2015-01-01

    The application of evanescent photovoltaic (PV) fields, generated by visible illumination of Fe:LiNbO 3 substrates, for parallel massive trapping and manipulation of micro- and nano-objects is critically reviewed. The technique has been often referred to as photovoltaic or photorefractive tweezers. The main advantage of the new method is that the involved electrophoretic and/or dielectrophoretic forces do not require any electrodes and large scale manipulation of nano-objects can be easily achieved using the patterning capabilities of light. The paper describes the experimental techniques for particle trapping and the main reported experimental results obtained with a variety of micro- and nano-particles (dielectric and conductive) and different illumination configurations (single beam, holographic geometry, and spatial light modulator projection). The report also pays attention to the physical basis of the method, namely, the coupling of the evanescent photorefractive fields to the dielectric response of the nano-particles. The role of a number of physical parameters such as the contrast and spatial periodicities of the illumination pattern or the particle deposition method is discussed. Moreover, the main properties of the obtained particle patterns in relation to potential applications are summarized, and first demonstrations reviewed. Finally, the PV method is discussed in comparison to other patterning strategies, such as those based on the pyroelectric response and the electric fields associated to domain poling of ferroelectric materials

  7. Massive Star Formation: Accreting from Companion X. Chen1 ...

    Indian Academy of Sciences (India)

    Abstract. We report the possible accretion from companion in the mas- sive star forming region (G350.69–0.49). This region seems to be a binary system composed of a diffuse object (possible nebulae or UC HII region) and a Massive Young Stellar Object (MYSO) seen in Spitzer IRAC image. The diffuse object and MYSO ...

  8. EVIDENCE THAT GAMMA-RAY BURST 130702A EXPLODED IN A DWARF SATELLITE OF A MASSIVE GALAXY

    International Nuclear Information System (INIS)

    Kelly, Patrick L.; Filippenko, Alexei V.; Fox, Ori D.; Zheng Weikang; Clubb, Kelsey I.

    2013-01-01

    GRB 130702A is a nearby long-duration gamma-ray burst (LGRB) discovered by the Fermi satellite whose associated afterglow was detected by the Palomar Transient Factory. Subsequent photometric and spectroscopic monitoring has identified a coincident broad-lined Type Ic supernova (SN), and nebular emission detected near the explosion site is consistent with a redshift of z = 0.145. The SN-GRB exploded at an offset of ∼7.''6 from the center of an inclined r = 18.1 mag red disk-dominated galaxy, and ∼0.''6 from the center of a much fainter r = 23 mag object. We obtained Keck-II DEIMOS spectra of the two objects and find a 2σ upper limit on their line-of-sight velocity offset of ∼ –1 . If we calculate the inclination angle of the massive red galaxy from its axis ratio and assume that its light is dominated by a very thin disk, the explosion would have a ∼60 kpc central offset, or ∼9 times the galaxy's half-light radius. A significant bulge or a thicker disk would imply a higher inclination angle and greater central offset. The substantial offset suggests that the faint source is a separate dwarf galaxy. The star-formation rate of the dwarf galaxy is ∼0.05 M ☉ yr –1 , and we place an upper limit on its oxygen abundance of 12 + log(O/H) < 8.16 dex. The identification of an LGRB in a dwarf satellite of a massive, metal-rich primary galaxy suggests that recent detections of LGRBs spatially coincident with metal-rich galaxies may be, in some cases, superpositions

  9. THERE ARE NO STARLESS MASSIVE PROTO-CLUSTERS IN THE FIRST QUADRANT OF THE GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Ginsburg, A.; Bally, J.; Battersby, C. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); Bressert, E. [European Southern Observatory, Karl Schwarzschild str. 2, D-85748 Garching bei Muenchen (Germany)

    2012-10-20

    We search the {lambda} = 1.1 mm Bolocam Galactic Plane Survey for clumps containing sufficient mass to form {approx}10{sup 4} M{sub Sun} star clusters. Eighteen candidate massive proto-clusters are identified in the first Galactic quadrant outside of the central kiloparsec. This sample is complete to clumps with mass M{sub clump} > 10{sup 4} M{sub Sun} and radius r {approx}< 2.5 pc. The overall Galactic massive cluster formation rate is CFR(M{sub cluster} > 10{sup 4}) {approx}<5 Myr{sup -1}, which is in agreement with the rates inferred from Galactic open clusters and M31 massive clusters. We find that all massive proto-clusters in the first quadrant are actively forming massive stars and place an upper limit of {tau}{sub starless} < 0.5 Myr on the lifetime of the starless phase of massive cluster formation. If massive clusters go through a starless phase with all of their mass in a single clump, the lifetime of this phase is very short.

  10. The Evolution of Low-Metallicity Massive Stars

    Science.gov (United States)

    Szécsi, Dorottya

    2016-07-01

    Massive star evolution taking place in astrophysical environments consisting almost entirely of hydrogen and helium - in other words, low-metallicity environments - is responsible for some of the most intriguing and energetic cosmic phenomena, including supernovae, gamma-ray bursts and gravitational waves. This thesis aims to investigate the life and death of metal-poor massive stars, using theoretical simulations of the stellar structure and evolution. Evolutionary models of rotating, massive stars (9-600 Msun) with an initial metal composition appropriate for the low-metallicity dwarf galaxy I Zwicky 18 are presented and analyzed. We find that the fast rotating models (300 km/s) become a particular type of objects predicted only at low-metallicity: the so-called Transparent Wind Ultraviolet INtense (TWUIN) stars. TWUIN stars are fast rotating massive stars that are extremely hot (90 kK), very bright and as compact as Wolf-Rayet stars. However, as opposed to Wolf-Rayet stars, their stellar winds are optically thin. As these hot objects emit intense UV radiation, we show that they can explain the unusually high number of ionizing photons of the dwarf galaxy I Zwicky 18, an observational quantity that cannot be understood solely based on the normal stellar population of this galaxy. On the other hand, we find that the most massive, slowly rotating models become another special type of object predicted only at low-metallicity: core-hydrogen-burning cool supergiant stars. Having a slow but strong stellar wind, these supergiants may be important contributors in the chemical evolution of young galactic globular clusters. In particular, we suggest that the low mass stars observed today could form in a dense, massive and cool shell around these, now dead, supergiants. This scenario is shown to explain the anomalous surface abundances observed in these low mass stars, since the shell itself, having been made of the mass ejected by the supergiant’s wind, contains nuclear

  11. Management of foreign object in the root canal of central incisor tooth

    Directory of Open Access Journals (Sweden)

    Mothanna Alrahabi

    2014-01-01

    Full Text Available There are several reports describing the impaction of foreign objects into the exposed pulp chambers and canals by patients, especially children as they often have the habit of inserting foreign objects in the oral cavity. These objects will become a potent source of infection.This case report describes the retrieval of a foreign object impacted into the root canal of a 12-year-old male patient who was referred to the endodontic specialty clinic at Taibah University College of Dentistry. The patient′s chief complaint was a pain in the upper left central tooth. Clinical examination revealed a complicated enamel-dentin fracture with a large caries cavity. A periapical radiographic image showed a radiopaque object in the root canal system. Stainless steel Hedstrom files were used to retrieve the object from the canal. Following a proper cleaning and shaping of the root canal system, an intra-canal calcium hydroxide dressing was placed for 1 week. The root canal system was then filled with sealer and gutta-percha using the lateral compaction technique and the tooth received an aesthetic restoration.

  12. The Destructive Birth of Massive Stars and Massive Star Clusters

    Science.gov (United States)

    Rosen, Anna; Krumholz, Mark; McKee, Christopher F.; Klein, Richard I.; Ramirez-Ruiz, Enrico

    2017-01-01

    Massive stars play an essential role in the Universe. They are rare, yet the energy and momentum they inject into the interstellar medium with their intense radiation fields dwarfs the contribution by their vastly more numerous low-mass cousins. Previous theoretical and observational studies have concluded that the feedback associated with massive stars' radiation fields is the dominant mechanism regulating massive star and massive star cluster (MSC) formation. Therefore detailed simulation of the formation of massive stars and MSCs, which host hundreds to thousands of massive stars, requires an accurate treatment of radiation. For this purpose, we have developed a new, highly accurate hybrid radiation algorithm that properly treats the absorption of the direct radiation field from stars and the re-emission and processing by interstellar dust. We use our new tool to perform a suite of three-dimensional radiation-hydrodynamic simulations of the formation of massive stars and MSCs. For individual massive stellar systems, we simulate the collapse of massive pre-stellar cores with laminar and turbulent initial conditions and properly resolve regions where we expect instabilities to grow. We find that mass is channeled to the massive stellar system via gravitational and Rayleigh-Taylor (RT) instabilities. For laminar initial conditions, proper treatment of the direct radiation field produces later onset of RT instability, but does not suppress it entirely provided the edges of the radiation-dominated bubbles are adequately resolved. RT instabilities arise immediately for turbulent pre-stellar cores because the initial turbulence seeds the instabilities. To model MSC formation, we simulate the collapse of a dense, turbulent, magnetized Mcl = 106 M⊙ molecular cloud. We find that the influence of the magnetic pressure and radiative feedback slows down star formation. Furthermore, we find that star formation is suppressed along dense filaments where the magnetic field is

  13. The Formation and Early Evolution of Embedded Massive Star Clusters

    Science.gov (United States)

    Barnes, Peter

    We propose to combine Spitzer, WISE, Herschel, and other archival spacecraft data with an existing ground- and space-based mm-wave to near-IR survey of molecular clouds over a large portion of the Milky Way, in order to systematically study the formation and early evolution of massive stars and star clusters, and provide new observational calibrations for a theoretical paradigm of this key astrophysical problem. Central Objectives: The Galactic Census of High- and Medium-mass Protostars (CHaMP) is a large, unbiased, uniform, and panchromatic survey of massive star and cluster formation and early evolution, covering 20°x6° of the Galactic Plane. Its uniqueness lies in the comprehensive molecular spectroscopy of 303 massive dense clumps, which have also been included in several archival spacecraft surveys. Our objective is a systematic demographic analysis of massive star and cluster formation, one which has not been possible without knowledge of our CHaMP cloud sample, including all clouds with embedded clusters as well as those that have not yet formed massive stars. For proto-clusters deeply embedded within dense molecular clouds, analysis of these space-based data will: 1. Yield a complete census of Young Stellar Objects in each cluster. 2. Allow systematic measurements of embedded cluster properties: spectral energy distributions, luminosity functions, protostellar and disk fractions, and how these vary with cluster mass, age, and density. Combined with other, similarly complete and unbiased infrared and mm data, CHaMP's goals include: 3. A detailed comparison of the embedded stellar populations with their natal dense gas to derive extinction maps, star formation efficiencies and feedback effects, and the kinematics, physics, and chemistry of the gas in and around the clusters. 4. Tying the demographics, age spreads, and timescales of the clusters, based on pre-Main Sequence evolution, to that of the dense gas clumps and Giant Molecular Clouds. 5. A

  14. Massive hydrothorax with malpositioned central venous catheter – Ultrasound detection

    Directory of Open Access Journals (Sweden)

    Neha Hasija

    2016-04-01

    Full Text Available Radioimaging is the gold standard for confirmation of the position of central venous catheter as well as its related complications. Use of ultrasound has been proven in guiding central venous cannulations, and it can also be used in detecting related complications. We report a case of a 2 year old child with hydrothorax causing desaturation due to malpositioned central venous catheter diagnosed by ultrasound in the delay for getting a radiograph.

  15. Star clusters containing massive, central black holes: evolution calculations

    International Nuclear Information System (INIS)

    Marchant, A.B.

    1980-01-01

    This dissertation presents a detailed, two-dimensional simulations of star cluster evolution. A Monte-Carlo method is adapted to simulate the development with time of isolated star clusters. Clusters which evolve on relaxation timescales with and without central black holes are treated. The method is flexible and rugged, rather than highly accurate. It treats the boundary conditions of stellar evaporation and tidal disruption by a central black hole in a precise, stochastic fashion. Dynamical cloning and renormalization and the use of a time-step adjustment algorithm enhance the feasibility of the method which simulates systems with wide ranges of intrinsic length and time scales. First, the method is applied to follow the development and core collapse of an initial Plummer-model cluster without a central black hole. Agreement of these results for early times with the results of previous authors serves as a verification of this method. Three calculations of cluster re-expansion, each beginning with the insertion of a black hole at the center of a highly collapsed cluster core is presented. Each case is characterized by a different value of initial black hole mass or black hole accretion efficiency for the consumption of debris from disrupted stars. It is found that for the special cases examined here substantial, but not catastrophic, growth of the central black hole may accompany core re-expansion. Also, the observability of the evolutionary phases associated with core collapse and re-expansion, constraints on x-ray sources which could be associated with growing black holes, and the observable signature of the cusp of stars surrounding a central black hole are discussed

  16. Massive Gravity

    OpenAIRE

    de Rham, Claudia

    2014-01-01

    We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali–Gabadadze–Porrati model (DGP), cascading gravity, and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware–Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally, we present alt...

  17. The central object R 136 in the gas nebula 30 Doradus - Structure, color, mass and excitation parameter

    Science.gov (United States)

    Feitzinger, J. V.; Schlosser, W.; Schmidt-Kaler, T.; Winkler, C.

    1980-04-01

    Photographic observations with the 3,6 m ESO and 0,61 m Bochum telescopes in different colours of the central part of the 30 Doradus Nebula are presented. The structure of the central object R 136 is studied by image analysis methods, i.e. digitalisation and contrast enhancement. The central object R 136 of the supergiant gas nebula 30 Doradus consists of three components; the main component covers an area of (0.7 pc)2. The components show a colour gradient, R 136a being much bluer than R 136c. This composite structure is seen in photographic IR, U and V likewise. A plot of the spectral intensity distribution from λ = 73 cm to 1550 Å of the central 2'.5 × 2'.5 region of 30 Doradus is given. The main contribution in the UV can be attributed to R 136. This object dominates the of the central part of 30 Doradus. It determines together with 16 other bright stars in the center the excitation parameter of the nebula. Its effective temperature lies between 50000 and 55000K and the tipper and lower mass values are 250 and 103 solar masses. The bolometric magnitude is brighter than -l4m. The inner structure of 30 Doradus can be explained as the result of the stellar-wind of R 136.

  18. Observations of Bright Massive Stars Using Small Size Telescopes

    Science.gov (United States)

    Beradze, Sopia; Kochiashvili, Nino

    2017-11-01

    The size of a telescope determines goals and objects of observations. During the latest decades it becomes more and more difficult to get photometric data of bright stars because most of telescopes of small sizes do not operate already. But there are rather interesting questions connected to the properties and evolution ties between different types of massive stars. Multi-wavelength photometric data are needed for solution of some of them. We are presenting our observational plans of bright Massive X-ray binaries, WR and LBV stars using a small size telescope. All these stars, which are presented in the poster are observational targets of Sopia Beradze's future PhD thesis. We already have got very interesting results on the reddening and possible future eruption of the massive hypergiant star P Cygni. Therefore, we decided to choose some additional interesting massive stars of different type for future observations. All Massive stars play an important role in the chemical evolution of galaxies because of they have very high mass loss - up to 10-4M⊙/a year. Our targets are on different evolutionary stages and three of them are the members of massive binaries. We plan to do UBVRI photometric observations of these stars using the 48 cm Cassegrain telescope of the Abastumani Astrophisical Observatory.

  19. Newly diagnosed primary hypothyroidism applicant with massive pericardial effusion and acute renal failure

    Directory of Open Access Journals (Sweden)

    Ates I

    2016-01-01

    Full Text Available Objective. While non-symptomatic pericardial effusion is seen in primary hypothyroidism, massive pericardial effusion is a very rare finding. In the literature, newly diagnosed primary hypothyroidism cases presenting with massive pericardial effusion or acute renal failure are present, but we did not encounter any case first presenting with combination of two signs. In this case report, primary hypothyroidism case that presenting with massive pericardial effusion and acute renal failure will be discussed.

  20. EVIDENCE THAT GAMMA-RAY BURST 130702A EXPLODED IN A DWARF SATELLITE OF A MASSIVE GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Patrick L.; Filippenko, Alexei V.; Fox, Ori D.; Zheng Weikang; Clubb, Kelsey I., E-mail: pkelly@astro.berkeley.edu [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

    2013-09-20

    GRB 130702A is a nearby long-duration gamma-ray burst (LGRB) discovered by the Fermi satellite whose associated afterglow was detected by the Palomar Transient Factory. Subsequent photometric and spectroscopic monitoring has identified a coincident broad-lined Type Ic supernova (SN), and nebular emission detected near the explosion site is consistent with a redshift of z = 0.145. The SN-GRB exploded at an offset of {approx}7.''6 from the center of an inclined r = 18.1 mag red disk-dominated galaxy, and {approx}0.''6 from the center of a much fainter r = 23 mag object. We obtained Keck-II DEIMOS spectra of the two objects and find a 2{sigma} upper limit on their line-of-sight velocity offset of {approx}<60 km s{sup -1}. If we calculate the inclination angle of the massive red galaxy from its axis ratio and assume that its light is dominated by a very thin disk, the explosion would have a {approx}60 kpc central offset, or {approx}9 times the galaxy's half-light radius. A significant bulge or a thicker disk would imply a higher inclination angle and greater central offset. The substantial offset suggests that the faint source is a separate dwarf galaxy. The star-formation rate of the dwarf galaxy is {approx}0.05 M{sub Sun} yr{sup -1}, and we place an upper limit on its oxygen abundance of 12 + log(O/H) < 8.16 dex. The identification of an LGRB in a dwarf satellite of a massive, metal-rich primary galaxy suggests that recent detections of LGRBs spatially coincident with metal-rich galaxies may be, in some cases, superpositions.

  1. The VLT-FLAMES Tarantula Survey. III. A very massive star in apparent isolation from the massive cluster R136

    NARCIS (Netherlands)

    Bestenlehner, J.M.; Vink, J.S.; Gräfener, G.; Najarro, F.; Evans, C.J.; Bastian, N.; Bonanos, A.Z.; Bressert, E.; Crowther, P.A.; Doran, E.; Friedrich, K.; Hénault-Brunet, V.; Herrero, A.; de Koter, A.; Langer, N.; Lennon, D.J.; Maíz Apellániz, J.; Sana, H.; Soszynski, I.; Taylor, W.D.

    2011-01-01

    VFTS 682 is located in an active star-forming region, at a projected distance of 29 pc from the young massive cluster R136 in the Tarantula Nebula of the Large Magellanic Cloud. It was previously reported as a candidate young stellar object, and more recently spectroscopically revealed as a

  2. The Black Hole Safari: Big Game Hunting in 30+ Massive Galaxies

    Science.gov (United States)

    McConnell, Nicholas J.; Ma, Chung-Pei; Janish, Ryan; Gebhardt, Karl; Lauer, Tod R.; Graham, James R.

    2015-01-01

    The current census of the most massive black holes in the local universe turns up an odd variety of galaxy hosts: central galaxies in rich clusters, second- or lower-ranked cluster members, and compact relics from the early universe. More extensive campaigns are required to explore the number density and environmental distribution of these monsters. Over the past three years we have collected a large set of stellar kinematic data with sufficient resolution to detect the gravitational signatures of supermassive black holes with MBH > 109 MSun. This Black Hole Safari targets enormous galaxies at the centers of nearby galaxy clusters, as well as their similarly luminous counterparts in weaker galaxy groups. To date we have observed more than 30 early-type galaxies with integral-field spectrographs on the Keck, Gemini North, and Gemini South telescopes. Here I present preliminary stellar kinematics from 10 objects.

  3. Fueling-Controlled the Growth of Massive Black Holes

    Science.gov (United States)

    Escala, A.

    2009-05-01

    We study the relation between nuclear massive black holes and their host spheroid gravitational potential. Using AMR numerical simulations, we analyze how gas is transported into the nuclear (central kpc) regions of galaxies. We study gas fueling onto the inner accretion disk (sub-pc scale) and star formation in a massive nuclear disk like those generally found in proto-spheroids (ULIRGs, SCUBA Galaxies). These sub-pc resolution simulations of gas fueling, which is mainly depleted by star formation, naturally satisfy the `M_BH-M_{virial}' relation, with a scatter considerably less than that observed. We find that a generalized version of the Kennicutt-Schmidt Law for starbursts is satisfied, in which the total gas depletion rate (dot M_gas=dot M_BH + M_SF scales as M_gas/t_orbital. See Escala (2007) for more details about this work.

  4. The MASSIVE survey. I. A volume-limited integral-field spectroscopic study of the most massive early-type galaxies within 108 Mpc

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Chung-Pei [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Greene, Jenny E.; Murphy, Jeremy D. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); McConnell, Nicholas [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Janish, Ryan [Department of Physics, University of California, Berkeley, CA 94720 (United States); Blakeslee, John P. [Dominion Astrophysical Observatory, NRC Herzberg Institute of Astrophysics, Victoria, BC V9E 2E7 (Canada); Thomas, Jens, E-mail: cpma@berkeley.edu [Max Planck-Institute for Extraterrestrial Physics, Giessenbachstr. 1, D-85741 Garching (Germany)

    2014-11-10

    Massive early-type galaxies represent the modern day remnants of the earliest major star formation episodes in the history of the universe. These galaxies are central to our understanding of the evolution of cosmic structure, stellar populations, and supermassive black holes, but the details of their complex formation histories remain uncertain. To address this situation, we have initiated the MASSIVE Survey, a volume-limited, multi-wavelength, integral-field spectroscopic (IFS) and photometric survey of the structure and dynamics of the ∼100 most massive early-type galaxies within a distance of 108 Mpc. This survey probes a stellar mass range M* ≳ 10{sup 11.5} M {sub ☉} and diverse galaxy environments that have not been systematically studied to date. Our wide-field IFS data cover about two effective radii of individual galaxies, and for a subset of them, we are acquiring additional IFS observations on sub-arcsecond scales with adaptive optics. We are also acquiring deep K-band imaging to trace the extended halos of the galaxies and measure accurate total magnitudes. Dynamical orbit modeling of the combined data will allow us to simultaneously determine the stellar, black hole, and dark matter halo masses. The primary goals of the project are to constrain the black hole scaling relations at high masses, investigate systematically the stellar initial mass function and dark matter distribution in massive galaxies, and probe the late-time assembly of ellipticals through stellar population and kinematical gradients. In this paper, we describe the MASSIVE sample selection, discuss the distinct demographics and structural and environmental properties of the selected galaxies, and provide an overview of our basic observational program, science goals and early survey results.

  5. GRAVITATIONAL SLINGSHOT OF YOUNG MASSIVE STARS IN ORION

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Sourav; Tan, Jonathan C., E-mail: s.chatterjee@astro.ufl.edu, E-mail: jt@astro.ufl.edu [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States)

    2012-08-01

    The Orion Nebula Cluster (ONC) is the nearest region of massive star formation and thus a crucial testing ground for theoretical models. Of particular interest among the ONC's {approx}1000 members are: {theta}{sup 1} Ori C, the most massive binary in the cluster with stars of masses 38 and 9 M{sub Sun }; the Becklin-Neugebauer (BN) object, a 30 km s{sup -1} runaway star of {approx}8 M{sub Sun }; and the Kleinmann-Low (KL) nebula protostar, a highly obscured, {approx}15 M{sub Sun} object still accreting gas while also driving a powerful, apparently 'explosive' outflow. The unusual behavior of BN and KL is much debated: How did BN acquire its high velocity? How is this related to massive star formation in the KL nebula? Here, we report the results of a systematic survey using {approx}10{sup 7} numerical experiments of gravitational interactions of the {theta}{sup 1}C and BN stars. We show that dynamical ejection of BN from this triple system at its observed velocity leaves behind a binary with total energy and eccentricity matching those observed for {theta}{sup 1}C. Five other observed properties of {theta}{sup 1}C are also consistent with it having ejected BN and altogether we estimate that there is only a {approx}< 10{sup -5} probability that {theta}{sup 1}C has these properties by chance. We conclude that BN was dynamically ejected from the {theta}{sup 1}C system about 4500 years ago. BN then plowed through the KL massive star-forming core within the last 1000 years causing its recently enhanced accretion and outflow activity.

  6. Effects of massive transfusion on oxygen availability

    Directory of Open Access Journals (Sweden)

    José Otávio Costa Auler Jr

    Full Text Available OBJECTIVE: To determine oxygen derived parameters, hemodynamic and biochemical laboratory data (2,3 Diphosphoglycerate, lactate and blood gases analysis in patients after cardiac surgery who received massive blood replacement. DESIGN: Prospective study. SETTING: Heart Institute (Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, Brazil. PARTICIPANTS: Twelve patients after cardiac surgery who received massive transfusion replacement; six of them evolved to a fatal outcome within the three-day postoperative follow-up. MEASUREMENTS AND MAIN RESULTS: The non-survivors group (n=6 presented high lactate levels and low P50 levels, when compared to the survivors group (p<0.05. Both groups presented an increase in oxygen consumption and O2 extraction, and there were no significant differences between them regarding these parameters. The 2,3 DPG levels were slightly reduced in both groups. CONCLUSIONS: This study shows that patients who are massively transfused following cardiovascular surgery present cell oxygenation disturbances probably as a result of O2 transport inadequacy.

  7. An infrared view of (candidate accretion) disks around massive young stars

    NARCIS (Netherlands)

    Bik, A.; Lenorzer, A.; Thi, W.F.; Puga Antolín, E.; Waters, L.B.F.M.; Kaper, L.; Martín-Hernández, L.N.

    2008-01-01

    Near-infrared surveys of high-mass star-forming regions start to shed light onto their stellar content. A particular class of objects found in these regions, the so-called massive Young Stellar Objects (YSOs) are surrounded by dense circumstellar material. Several near- and mid-infrared diagnostic

  8. The Evolution of Massive Stars: a Selection of Facts and Questions

    Science.gov (United States)

    Vanbeveren, D.

    In the present paper we discuss a selection of facts and questions related to observations and evolutionary calculations of massive single stars and massive stars in interacting binaries. We focus on the surface chemical abundances, the role of stellar winds, the early Be-stars, the high mass X-ray binaries and the effects of rotation on stellar evolution. Finally, we present an unconventionally formed object scenario (UFO-scenario) of WR binaries in dense stellar environments.

  9. Digging for red nuggets: discovery of hot halos surrounding massive, compact, relic galaxies

    Science.gov (United States)

    Werner, N.; Lakhchaura, K.; Canning, R. E. A.; Gaspari, M.; Simionescu, A.

    2018-04-01

    We present the results of Chandra X-ray observations of the isolated, massive, compact, relic galaxies MRK 1216 and PGC 032873. Compact massive galaxies observed at z > 2, also called red nuggets, formed in quick dissipative events and later grew by dry mergers into the local giant ellipticals. Due to the stochastic nature of mergers, a few of the primordial massive galaxies avoided the mergers and remained untouched over cosmic time. We find that the hot atmosphere surrounding MRK 1216 extends far beyond the stellar population and has an 0.5-7 keV X-ray luminosity of LX = (7.0 ± 0.2) × 1041 erg s-1, which is similar to the nearby X-ray bright giant ellipticals. The hot gas has a short central cooling time of ˜50 Myr and the galaxy has a ˜13 Gyr old stellar population. The presence of an X-ray atmosphere with a short nominal cooling time and the lack of young stars indicate the presence of a sustained heating source, which prevented star formation since the dissipative origin of the galaxy 13 Gyrs ago. The central temperature peak and the presence of radio emission in the core of the galaxy indicate that the heating source is radio-mechanical AGN feedback. Given that both MRK 1216 and PGC 032873 appear to have evolved in isolation, the order of magnitude difference in their current X-ray luminosity could be traced back to a difference in the ferocity of the AGN outbursts in these systems. Finally, we discuss the potential connection between the presence of hot halos around such massive galaxies and the growth of super/over-massive black holes via chaotic cold accretion.

  10. Theories of central engine for long gamma-ray bursts

    Science.gov (United States)

    Nagataki, Shigehiro

    2018-02-01

    Long GRBs are the most powerful explosions in the universe since the Big Bang. At least, some fraction of long GRBs are born from the death of massive stars. Likewise, only some fraction of massive stars that satisfy additional special conditions explode as long GRBs associated with supernovae/hypernovae. In this paper, we discuss the explosion mechanism of long GRBs associated with hypernovae: ‘the central engine of long GRBs’. The central engine of long GRBs is very different from that of core-collapse supernovae, although the mechanism of the engine is still not firmly established. In this paper, we review theoretical studies of the central engine of long GRBs. First, we discuss possible progenitor stars. Then several promising mechanisms of the central engine—such as black hole and magnetar formation—will be reviewed. We will also mention some more exotic models. Finally, we describe prospects for future studies of the central engine of long GRBs.

  11. Massive Memory Revisited: Limitations on Storage Capacity for Object Details in Visual Long-Term Memory

    Science.gov (United States)

    Cunningham, Corbin A.; Yassa, Michael A.; Egeth, Howard E.

    2015-01-01

    Previous work suggests that visual long-term memory (VLTM) is highly detailed and has a massive capacity. However, memory performance is subject to the effects of the type of testing procedure used. The current study examines detail memory performance by probing the same memories within the same subjects, but using divergent probing methods. The…

  12. Proxy-equation paradigm: A strategy for massively parallel asynchronous computations

    Science.gov (United States)

    Mittal, Ankita; Girimaji, Sharath

    2017-09-01

    Massively parallel simulations of transport equation systems call for a paradigm change in algorithm development to achieve efficient scalability. Traditional approaches require time synchronization of processing elements (PEs), which severely restricts scalability. Relaxing synchronization requirement introduces error and slows down convergence. In this paper, we propose and develop a novel "proxy equation" concept for a general transport equation that (i) tolerates asynchrony with minimal added error, (ii) preserves convergence order and thus, (iii) expected to scale efficiently on massively parallel machines. The central idea is to modify a priori the transport equation at the PE boundaries to offset asynchrony errors. Proof-of-concept computations are performed using a one-dimensional advection (convection) diffusion equation. The results demonstrate the promise and advantages of the present strategy.

  13. A single population of red globular clusters around the massive compact galaxy NGC 1277

    Science.gov (United States)

    Beasley, Michael A.; Trujillo, Ignacio; Leaman, Ryan; Montes, Mireia

    2018-03-01

    Massive galaxies are thought to form in two phases: an initial collapse of gas and giant burst of central star formation, followed by the later accretion of material that builds up their stellar and dark-matter haloes. The systems of globular clusters within such galaxies are believed to form in a similar manner. The initial central burst forms metal-rich (spectrally red) clusters, whereas more metal-poor (spectrally blue) clusters are brought in by the later accretion of less-massive satellites. This formation process is thought to result in the multimodal optical colour distributions that are seen in the globular cluster systems of massive galaxies. Here we report optical observations of the massive relic-galaxy candidate NGC 1277—a nearby, un-evolved example of a high-redshift ‘red nugget’ galaxy. We find that the optical colour distribution of the cluster system of NGC 1277 is unimodal and entirely red. This finding is in strong contrast to other galaxies of similar and larger stellar mass, the cluster systems of which always exhibit (and are generally dominated by) blue clusters. We argue that the colour distribution of the cluster system of NGC 1277 indicates that the galaxy has undergone little (if any) mass accretion after its initial collapse, and use simulations of possible merger histories to show that the stellar mass due to accretion is probably at most ten per cent of the total stellar mass of the galaxy. These results confirm that NGC 1277 is a genuine relic galaxy and demonstrate that blue clusters constitute an accreted population in present-day massive galaxies.

  14. Peering to the Heart of Massive Star Birth

    Science.gov (United States)

    Tan, Jonathan

    2015-10-01

    We propose a small survey of massive/intermediate-mass protostars with WFC3/IR to probe J and H band continuum emission, the Pa-beta and the [FeII] emission. The protostar sample is already the subject of approved SOFIA-FORCAST observations from 10-40 microns. Combined with sophisticated radiative transfer models, these observations are providing the most detailed constraints on the nature of massive protostars, their luminosities, outflow cavity structures and orientations, and distribution of surrounding dense core gas and dust. Recently, we were also awarded ALMA Cycle 3 time to study these sources at up to 0.14 resolution. The proposed HST observations, with very similar resolution, have three main goals: 1) Detect and characterize J and H band continuum emission from the massive/intermediate-mass protostars, which is expected to arise from jet and outflow knot features and from scattered light emerging from the outflow cavities; 2) Detect and characterize Pa-beta and [FeII] line emission tracing ionized and FUV-illuminated regions around the massive protostars, important diagnostics of the protostellar source and its outflow structure; 3) Search for lower-mass protostars that may be clustered around the forming massive protostar. All of these objectives will help test massive star formation theories. The high sensitivity and angular resolution of WFC3/IR enables these observations to be carried out efficiently in a timely fashion. Mid-Cycle observations are critical for near contemporaneous observation with ALMA, since jet/outflow knots may have large proper motions, and to maximize the potential time baseline for a future HST study of jet/outflow proper motions.

  15. MASSIVE PROTOPLANETARY DISKS IN ORION BEYOND THE TRAPEZIUM CLUSTER

    International Nuclear Information System (INIS)

    Mann, Rita K.; Williams, Jonathan P.

    2009-01-01

    We present Submillimeter Array 1 The Submillimeter Array is a joint project between the Submillimeter Astrophysical Observatory and the Academica Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academica Sinica. observations of the 880 μm continuum emission from three circumstellar disks around young stars in Orion that lie several arcminutes (∼> 1 pc) north of the Trapezium cluster. Two of the three disks are in the binary system 253-1536. Silhouette disks 216-0939 and 253-1536a are found to be more massive than any previously observed Orion disks, with dust masses derived from their submillimeter emission of 0.045 M sun and 0.066 M sun , respectively. The existence of these massive disks reveals that the disk mass distribution in Orion does extend to high masses, and that the truncation observed in the central Trapezium cluster is a result of photoevaporation due to the proximity of O-stars. 253-1536b has a disk mass of 0.018 M sun , making the 253-1536 system the first optical binary in which each protoplanetary disk is massive enough to potentially form solar systems.

  16. Reliable Reporting for Massive M2M Communications with Periodic Resource Pooling

    DEFF Research Database (Denmark)

    Madueño, Germán Corrales; Stefanovic, Cedomir; Popovski, Petar

    2014-01-01

    This letter considers a wireless M2M communication scenario with a massive number of M2M devices. Each device needs to send its reports within a given deadline and with certain reliability, e.g., 99.99%. A pool of resources available to all M2M devices is periodically available for transmission...... to guarantee the desired reliability of the report delivery within the deadline. The fact that the pool of resources is used by a massive number of devices allows to base the dimensioning on the central limit theorem. The results are interpreted in the context of LTE, but they are applicable to any M2M...

  17. Spinning Kerr black holes with stationary massive scalar clouds: the large-coupling regime

    Energy Technology Data Exchange (ETDEWEB)

    Hod, Shahar [Marine sciences, The Ruppin Academic Center,Ruppin, Emeq Hefer 40250 (Israel); Biotechnology, The Hadassah Academic College,37 Hanevi’im St., Jerusalem 9101001 (Israel)

    2017-01-09

    We study analytically the Klein-Gordon wave equation for stationary massive scalar fields linearly coupled to spinning Kerr black holes. In particular, using the WKB approximation, we derive a compact formula for the discrete spectrum of scalar field masses which characterize the stationary composed Kerr-black-hole-massive-scalar-field configurations in the large-coupling regime Mμ≫1 (here M and μ are respectively the mass of the central black hole and the proper mass of the scalar field). We confirm our analytically derived formula for the Kerr-scalar-field mass spectrum with numerical data that recently appeared in the literature.

  18. Massive Submucosal Ganglia in Colonic Inertia.

    Science.gov (United States)

    Naemi, Kaveh; Stamos, Michael J; Wu, Mark Li-Cheng

    2018-02-01

    - Colonic inertia is a debilitating form of primary chronic constipation with unknown etiology and diagnostic criteria, often requiring pancolectomy. We have occasionally observed massively enlarged submucosal ganglia containing at least 20 perikarya, in addition to previously described giant ganglia with greater than 8 perikarya, in cases of colonic inertia. These massively enlarged ganglia have yet to be formally recognized. - To determine whether such "massive submucosal ganglia," defined as ganglia harboring at least 20 perikarya, characterize colonic inertia. - We retrospectively reviewed specimens from colectomies of patients with colonic inertia and compared the prevalence of massive submucosal ganglia occurring in this setting to the prevalence of massive submucosal ganglia occurring in a set of control specimens from patients lacking chronic constipation. - Seven of 8 specimens affected by colonic inertia harbored 1 to 4 massive ganglia, for a total of 11 massive ganglia. One specimen lacked massive ganglia but had limited sampling and nearly massive ganglia. Massive ganglia occupied both superficial and deep submucosal plexus. The patient with 4 massive ganglia also had 1 mitotically active giant ganglion. Only 1 massive ganglion occupied the entire set of 10 specimens from patients lacking chronic constipation. - We performed the first, albeit distinctly small, study of massive submucosal ganglia and showed that massive ganglia may be linked to colonic inertia. Further, larger studies are necessary to determine whether massive ganglia are pathogenetic or secondary phenomena, and whether massive ganglia or mitotically active ganglia distinguish colonic inertia from other types of chronic constipation.

  19. New massive gravity

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Hohm, Olaf; Townsend, Paul K.

    2012-01-01

    We present a brief review of New Massive Gravity, which is a unitary theory of massive gravitons in three dimensions obtained by considering a particular combination of the Einstein-Hilbert and curvature squared terms.

  20. THE MASSIVE SATELLITE POPULATION OF MILKY-WAY-SIZED GALAXIES

    International Nuclear Information System (INIS)

    Rodríguez-Puebla, Aldo; Avila-Reese, Vladimir; Drory, Niv

    2013-01-01

    Several occupational distributions for satellite galaxies more massive than m * ≈ 4 × 10 7 M ☉ around Milky-Way (MW)-sized hosts are presented and used to predict the internal dynamics of these satellites as a function of m * . For the analysis, a large galaxy group mock catalog is constructed on the basis of (sub)halo-to-stellar mass relations fully constrained with currently available observations, namely the galaxy stellar mass function decomposed into centrals and satellites, and the two-point correlation functions at different masses. We find that 6.6% of MW-sized galaxies host two satellites in the mass range of the Small and Large Magellanic Clouds (SMC and LMC, respectively). The probabilities of the MW-sized galaxies having one satellite equal to or larger than the LMC, two satellites equal to or larger than the SMC, or three satellites equal to or larger than Sagittarius (Sgr) are ≈0.26, 0.14, and 0.14, respectively. The cumulative satellite mass function of the MW, N s (≥m * ) , down to the mass of the Fornax dwarf is within the 1σ distribution of all the MW-sized galaxies. We find that MW-sized hosts with three satellites more massive than Sgr (as the MW) are among the most common cases. However, the most and second most massive satellites in these systems are smaller than the LMC and SMC by roughly 0.7 and 0.8 dex, respectively. We conclude that the distribution N s (≥m * ) for MW-sized galaxies is quite broad, the particular case of the MW being of low frequency but not an outlier. The halo mass of MW-sized galaxies correlates only weakly with N s (≥m * ). Then, it is not possible to accurately determine the MW halo mass by means of its N s (≥m * ); from our catalog, we constrain a lower limit of 1.38 × 10 12 M ☉ at the 1σ level. Our analysis strongly suggests that the abundance of massive subhalos should agree with the abundance of massive satellites in all MW-sized hosts, i.e., there is not a missing (massive) satellite problem

  1. Transarterial embolization for postoperative massive hemorrhage in patients with abdominal tumors

    International Nuclear Information System (INIS)

    Wang Zhiwei; Shi Haifeng; Sun Hao; Zhou Kang; Li Xiaoguang; Pan Jie; Zhang Xiaobo; Liu Wei; Yang Ning; Jin Zhengyu

    2010-01-01

    Objective: To discuss the feasibility and effectiveness of transarterial embolization for the management of postoperative massive hemorrhage in patients with abdominal tumors. Methods: Between January 2004 and December 2009 in authors' hospital transarterial embolization for postoperative massive hemorrhage was performed in thirteen patients with abdominal tumors. The clinical data and the technical points were retrospectively analyzed. Results: Of 13 patients,the bleeding was completely controlled in 10 after single embolization procedure. Re-bleeding occurred in the other 3 patients, and angiography showed the new bleeding arteries. Trans arterial embolization was carried out again, and the bleeding was successfully stopped in 2 patients. The remaining one patient had to be treated with surgery as the microcatheter could not be super-selectively placed into the bleeding vessel. The overall clinical success rate of trans arterial embolization for postoperative massive hemorrhage was 92% (12 /13). No severe complications occurred. Conclusion: Trans arterial embolization is a safe and effective treatment for postoperative massive hemorrhage in patients with abdominal tumors. (authors)

  2. STABLE ISOTOPE GEOCHEMISTRY OF MASSIVE ICE

    Directory of Open Access Journals (Sweden)

    Yurij K. Vasil’chuk

    2016-01-01

    Full Text Available The paper summarises stable-isotope research on massive ice in the Russian and North American Arctic, and includes the latest understanding of massive-ice formation. A new classification of massive-ice complexes is proposed, encompassing the range and variabilityof massive ice. It distinguishes two new categories of massive-ice complexes: homogeneousmassive-ice complexes have a similar structure, properties and genesis throughout, whereasheterogeneous massive-ice complexes vary spatially (in their structure and properties andgenetically within a locality and consist of two or more homogeneous massive-ice bodies.Analysis of pollen and spores in massive ice from Subarctic regions and from ice and snow cover of Arctic ice caps assists with interpretation of the origin of massive ice. Radiocarbon ages of massive ice and host sediments are considered together with isotope values of heavy oxygen and deuterium from massive ice plotted at a uniform scale in order to assist interpretation and correlation of the ice.

  3. Hyper-massive cloud, shock and stellar formation efficiency

    International Nuclear Information System (INIS)

    Louvet, Fabien

    2014-01-01

    O and B types stars are of paramount importance in the energy budget of galaxies and play a crucial role enriching the interstellar medium. However, their formation, unlike that of solar-type stars, is still subject to debate, if not an enigma. The earliest stages of massive star formation and the formation of their parent cloud are still crucial astrophysical questions that drew a lot of attention in the community, both from the theoretical and observational perspective, during the last decade. It has been proposed that massive stars are born in massive dense cores that form through very dynamic processes, such as converging flows of gas. During my PhD, I conducted a thorough study of the formation of dense cores and massive stars in the W43-MM1 supermassive structure, located at 6 kpc from the sun. At first, I showed a direct correlation between the star formation efficiency and the volume gas density of molecular clouds, in contrast with scenarios suggested by previous studies. Indeed, the spatial distribution and mass function of the massive dense cores currently forming in W43-MM1 suggests that this supermassive filament is undergoing a star formation burst, increasing as one approaches its center. I compared these observational results with the most recent numerical and analytical models of star formation. This comparison not only provides new constraints on the formation of supermassive filaments, but also suggests that understanding star formation in high density, extreme ridges requires a detailed portrait of the structure of these exceptional objects. Second, having shown that the formation of massive stars depends strongly on the properties of the ridges where they form, I studied the formation processes of these filaments, thanks of the characterization of their global dynamics. Specifically, I used a tracer of shocks (SiO molecule) to disentangle the feedback of local star formation processes (bipolar jets and outflows) from shocks tracing the pristine

  4. The Cosmogony of Super-Massive Black Holes

    International Nuclear Information System (INIS)

    Duschl, Wolfgang J; Strittmatter, Peter A

    2012-01-01

    We summarize our recent results on the evolution of super-massive black holes in the cores of galaxies. Our models are based on the viscous, Eddington-limited evolution of self-gravitating accretion disks. We find that, within this framework, one can explain the growth time scales and the luminosities of individual objects as well as the variation of these quantities for AGN with different black hole masses.

  5. A GIANT RADIO HALO IN THE MASSIVE AND MERGING CLUSTER ABELL 1351

    International Nuclear Information System (INIS)

    Giacintucci, S.; Venturi, T.; Cassano, R.; Dallacasa, D.; Brunetti, G.

    2009-01-01

    We report on the detection of diffuse radio emission in the X-ray luminous and massive galaxy cluster A 1351 (z = 0.322) using archival Very Large Array data at 1.4 GHz. Given its central location, morphology, and Mpc-scale extent, we classify the diffuse source as a giant radio halo. X-ray and weak lensing studies show A 1351 to be a system undergoing a major merger. The halo is associated with the most massive substructure. The presence of this source is explained assuming that merger-driven turbulence may re-accelerate high-energy particles in the intracluster medium and generate diffuse radio emission on the cluster scale. The position of A 1351 in the log P 1.4GHz -log L X plane is consistent with that of all other radio-halo clusters known to date, supporting a causal connection between the unrelaxed dynamical state of massive (>10 15 M sun ) clusters and the presence of giant radio halos.

  6. Network Analysis of an Emergent Massively Collaborative Creation on Video Sharing Website

    Science.gov (United States)

    Hamasaki, Masahiro; Takeda, Hideaki; Nishimura, Takuichi

    The Web technology enables numerous people to collaborate in creation. We designate it as massively collaborative creation via the Web. As an example of massively collaborative creation, we particularly examine video development on Nico Nico Douga, which is a video sharing website that is popular in Japan. We specifically examine videos on Hatsune Miku, a version of a singing synthesizer application software that has inspired not only song creation but also songwriting, illustration, and video editing. As described herein, creators of interact to create new contents through their social network. In this paper, we analyzed the process of developing thousands of videos based on creators' social networks and investigate relationships among creation activity and social networks. The social network reveals interesting features. Creators generate large and sparse social networks including some centralized communities, and such centralized community's members shared special tags. Different categories of creators have different roles in evolving the network, e.g., songwriters gather more links than other categories, implying that they are triggers to network evolution.

  7. A visualization of null geodesics for the bonnor massive dipole

    Directory of Open Access Journals (Sweden)

    G. Andree Oliva Mercado

    2015-08-01

    Full Text Available In this work we simulate null geodesics for the Bonnor massive dipole metric by implementing a symbolic-numerical algorithm in Sage and Python. This program is also capable of visualizing in 3D, in principle, the geodesics for any given metric. Geodesics are launched from a common point, collectively forming a cone of light beams, simulating a solid-angle section of a point source in front of a massive object with a magnetic field. Parallel light beams also were considered, and their bending due to the curvature of the space-time was simulated.

  8. Recent Results on Central Compact Objects

    Science.gov (United States)

    Halpern, Jules P.; Gotthelf, E. V.

    2011-09-01

    We will review the latest observational results and theoretical puzzles about the class of central compact objects (CCOs) in supernova remnants (SNRs), 10 isolated neutron stars (NSs) with steady, thermal X-ray emission and absence of a surrounding pulsar wind nebula. Three CCOs have detected X-ray pulsations, with periods of 0.105, 0.112, and 0.424 s. X-ray timing studies reveal that their spin-down rates are extremely small, implying dipole magnetic fields of only 3.e10-1.e11 G, which is unprecedented among the population of young pulsars. In the absence of a stronger magnetic field, it is difficult to explain the high temperatures of their surface hot spots, which may instead require a magnetic field configuration that is different from a centered dipole. While CCOs are inconspicuous relative to ordinary young pulsars and active magnetars, that they are found in SNRs in comparable numbers to other classes of NSs implies that they must represent a significant fraction of NS births. Nevertheless, they fall in a region of the P,P-dot diagram for radio pulsars that is underpopulated, so it is not clear if CCOs are intrinsically radio quiet, and what happens to their descendants, the "orphaned CCOs" whose SNRs have dissipated. It has been speculated that if their magnetic fields were initially strong but were buried by prompt fall-back of supernova debris, then the dipole field may eventually diffuse back to the surface, and CCOs could join the main population of ordinary pulsars. We will also discuss how the absence of detected pulsations from the majority of CCOs makes them difficult to distinguish from magnetars in quiescence, which have X-ray spectra and luminosities similar to those of CCOs. However, they can be distinguished with long-term monitoring, since magnetars are eventually variable, while CCOs are steady X-ray emitters.

  9. Stratigraphic setting and mineralogy of the Arctic volcanogenic massive sulfide prospect, Ambler district, Alaska.

    Science.gov (United States)

    Schmidt, J.M.

    1986-01-01

    The Arctic prospect, south central Brooks Range, is among the 30 largest of 508 volcanic-hosted massive sulphide deposits in the world. The massive sulphide lenses are interlayered with graphitic schist between metamorphosed rhyolite porphyries in Middle Devonian to early Mississippian metamorphosed volcanic, volcaniclastic and sedimentary rocks. Hydrothermal alteration is of three types: chloritic, phyllic s.l., and pyrite-phengite, each type strata-distinctively and respectively below, in, and above the sulphides. Maximum alteration conforms with metal zoning in the sulfides to suggest predominantly northwestward dispersal from a linear vent area in the elongate basin containing the deposit.-G.J.N.

  10. Dissolved Massive Metal-rich Globular Clusters Can Cause the Range of UV Upturn Strengths Found among Early-type Galaxies

    Science.gov (United States)

    Goudfrooij, Paul

    2018-04-01

    I discuss a scenario in which the ultraviolet (UV) upturn of giant early-type galaxies (ETGs) is primarily due to helium-rich stellar populations that formed in massive metal-rich globular clusters (GCs), which subsequently dissolved in the strong tidal field in the central regions of the massive host galaxy. These massive GCs are assumed to show UV upturns similar to those observed recently in M87, the central giant elliptical galaxy in the Virgo cluster of galaxies. Data taken from the literature reveal a strong correlation between the strength of the UV upturn and the specific frequency of metal-rich GCs in ETGs. Adopting a Schechter function parameterization of GC mass functions, simulations of long-term dynamical evolution of GC systems show that the observed correlation between UV upturn strength and GC specific frequency can be explained by variations in the characteristic truncation mass {{ \\mathcal M }}{{c}} such that {{ \\mathcal M }}{{c}} increases with ETG luminosity in a way that is consistent with observed GC luminosity functions in ETGs. These findings suggest that the nature of the UV upturn in ETGs and the variation of its strength among ETGs are causally related to that of helium-rich populations in massive GCs, rather than intrinsic properties of field stars in massive galactic spheroids. With this in mind, I predict that future studies will find that [N/Fe] decreases with increasing galactocentric radius in massive ETGs, and that such gradients have the largest amplitudes in ETGs with the strongest UV upturns.

  11. Multi-wavelength investigations on feedback of massive star formation

    Science.gov (United States)

    Yuan, Jinghua

    2014-05-01

    In the course of massive star formation, outflows, ionizing radiation and intense stellar winds could heavily affect their adjacent environs and natal clouds. There are several outstanding open questions related to these processes: i) whether they can drive turbulence in molecular clouds; ii) whether they are able to trigger star formation; iii) whether they can destroy natal clouds to terminate star formation at low efficiencies. This thesis investigates feedback in different stages of massive star formation. Influence of such feedback to the ambient medium has been revealed. A new type of millimeter methanol maser is detected for the first time. An uncommon bipolar outflow prominent in the mid-infrared is discovered. And features of triggered star formation are found on the border of an infrared bubble and in the surroundings of a Herbig Be star. Extended green objects (EGOs) are massive outflow candidates showing prominent shocked features in the mid-infrared. We have carried out a high resolution study of the EGO G22.04+0.22 (hereafter, G22) based on archived SMA data. Continuum and molecular lines at 1.3 mm reveal that G22 is still at a hot molecular core stage. A very young multi-polar outflow system is detected, which is interacting with the adjacent dense gas. Anomalous emission features from CH3OH (8,-1,8 - 7,0,7) and CH3OH (4,2,2 - 3,1,2) are proven to be millimeter masers. It is the first time that maser emission of CH3OH (8,-1,8 - 7,0,7) at 218.440 GHz is detected in a massive star-forming region. Bipolar outflows have been revealed and investigated almost always in the microwave or radio domain. It's sort of rare that hourglass-shaped morphology be discovered in the mid-infrared. Based on GLIMPSE data, we have discovered a bipolar object resembling an hourglass at 8.0 um. It is found to be associated with IRAS 18114-1825. Analysis based on fitted SED, optical spectroscopy, and infrared color indices suggests IRAS 18114-1825 is an uncommon bipolar

  12. Magnetic resonance imaging of massive bone allografts with histologic correlation

    International Nuclear Information System (INIS)

    Hoeffner, E.G.; Soulen, R.L.; Ryan, J.R.; Qureshi, F.

    1996-01-01

    The objective of this study was to better understand the MRI appearance of massive bone allografts. The MRI findings of three massive bone allografts imaged in vivo were correlated with the histologic findings following removal of the allografts. A fourth allograft, never implanted, was imaged and evaluated histologically. Allografts were placed for the treatment of primary or recurrent osteosarcoma. The in-vivo allografts have a heterogeneous appearance on MRI which we attribute to the revascularization process. Fibrovascular connective tissue grows into the graft in a patchy, focal fashion, down the medullary canal from the graft-host junction and adjacent to the periosteum. The marrow spaces are initially devoid of normal cellular elements and occupied by fat and gelatinous material. This normal postoperative appearance of massive bone allografts must not be interpreted as recurrent neoplasm or infection in the allograft. Recognition of these complications rests on features outside the marrow. (orig./MG)

  13. Massive memory revisited: Limitations on storage capacity for object details in visual long-term memory

    OpenAIRE

    Cunningham, Corbin A.; Yassa, Michael A.; Egeth, Howard E.

    2015-01-01

    Previous work suggests that visual long-term memory (VLTM) is highly detailed and has a massive capacity. However, memory performance is subject to the effects of the type of testing procedure used. The current study examines detail memory performance by probing the same memories within the same subjects, but using divergent probing methods. The results reveal that while VLTM representations are typically sufficient to support performance when the procedure probes gist-based information, they...

  14. HALO EXPANSION IN COSMOLOGICAL HYDRO SIMULATIONS: TOWARD A BARYONIC SOLUTION OF THE CUSP/CORE PROBLEM IN MASSIVE SPIRALS

    Energy Technology Data Exchange (ETDEWEB)

    Maccio, A. V.; Stinson, G. [Max-Planck-Institut fuer Astronomie, 69117 Heidelberg (Germany); Brook, C. B.; Gibson, B. K. [University of Central Lancashire, Jeremiah Horrocks Institute for Astrophysics and Supercomputing, Preston PR1 2HE (United Kingdom); Wadsley, J.; Couchman, H. M. P. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Shen, S. [Department of Astronomy and Astrophysics, University of California Santa Cruz, Santa Cruz, CA 95064 (United States); Quinn, T., E-mail: maccio@mpia.de, E-mail: stinson@mpia.de [Astronomy Department, University of Washington, Seattle, WA 98195-1580 (United States)

    2012-01-15

    A clear prediction of the cold dark matter (CDM) model is the existence of cuspy dark matter halo density profiles on all mass scales. This is not in agreement with the observed rotation curves of spiral galaxies, challenging on small scales the otherwise successful CDM paradigm. In this work we employ high-resolution cosmological hydrodynamical simulations to study the effects of dissipative processes on the inner distribution of dark matter in Milky Way like objects (M Almost-Equal-To 10{sup 12} M{sub Sun }). Our simulations include supernova feedback, and the effects of the radiation pressure of massive stars before they explode as supernovae. The increased stellar feedback results in the expansion of the dark matter halo instead of contraction with respect to N-body simulations. Baryons are able to erase the dark matter cuspy distribution, creating a flat, cored, dark matter density profile in the central several kiloparsecs of a massive Milky-Way-like halo. The profile is well fit by a Burkert profile, with fitting parameters consistent with the observations. In addition, we obtain flat rotation curves as well as extended, exponential stellar disk profiles. While the stellar disk we obtain is still partially too thick to resemble the Milky Way thin disk, this pilot study shows that there is enough energy available in the baryonic component to alter the dark matter distribution even in massive disk galaxies, providing a possible solution to the long-standing problem of cusps versus cores.

  15. Compact objects and accretion disks

    NARCIS (Netherlands)

    Blandford, Roger; Agol, Eric; Broderick, Avery; Heyl, Jeremy; Koopmans, Leon; Lee, Hee-Won

    2002-01-01

    Recent developments in the spectropolarimetric study of compact objects, specifically black holes (stellar and massive) and neutron stars are reviewed. The lectures are organized around five topics: disks, jets, outflows, neutron stars and black holes. They emphasize physical mechanisms and are

  16. Objective Lightning Probability Forecasts for East-Central Florida Airports

    Science.gov (United States)

    Crawford, Winfred C.

    2013-01-01

    The forecasters at the National Weather Service in Melbourne, FL, (NWS MLB) identified a need to make more accurate lightning forecasts to help alleviate delays due to thunderstorms in the vicinity of several commercial airports in central Florida at which they are responsible for issuing terminal aerodrome forecasts. Such forecasts would also provide safer ground operations around terminals, and would be of value to Center Weather Service Units serving air traffic controllers in Florida. To improve the forecast, the AMU was tasked to develop an objective lightning probability forecast tool for the airports using data from the National Lightning Detection Network (NLDN). The resulting forecast tool is similar to that developed by the AMU to support space launch operations at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) for use by the 45th Weather Squadron (45 WS) in previous tasks (Lambert and Wheeler 2005, Lambert 2007). The lightning probability forecasts are valid for the time periods and areas needed by the NWS MLB forecasters in the warm season months, defined in this task as May-September.

  17. The dynamics of massive starless cores with ALMA

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Jonathan C. [Departments of Astronomy and Physics, University of Florida, Gainesville, FL 32611 (United States); Kong, Shuo; Butler, Michael J. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Caselli, Paola [School of Physics and Astronomy, The University of Leeds, Leeds LS2 9JT (United Kingdom); Fontani, Francesco [INAF-Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze (Italy)

    2013-12-20

    How do stars that are more massive than the Sun form, and thus how is the stellar initial mass function (IMF) established? Such intermediate- and high-mass stars may be born from relatively massive pre-stellar gas cores, which are more massive than the thermal Jeans mass. The turbulent core accretion model invokes such cores as being in approximate virial equilibrium and in approximate pressure equilibrium with their surrounding clump medium. Their internal pressure is provided by a combination of turbulence and magnetic fields. Alternatively, the competitive accretion model requires strongly sub-virial initial conditions that then lead to extensive fragmentation to the thermal Jeans scale, with intermediate- and high-mass stars later forming by competitive Bondi-Hoyle accretion. To test these models, we have identified four prime examples of massive (∼100 M {sub ☉}) clumps from mid-infrared extinction mapping of infrared dark clouds. Fontani et al. found high deuteration fractions of N{sub 2}H{sup +} in these objects, which are consistent with them being starless. Here we present ALMA observations of these four clumps that probe the N{sub 2}D{sup +} (3-2) line at 2.''3 resolution. We find six N{sub 2}D{sup +} cores and determine their dynamical state. Their observed velocity dispersions and sizes are broadly consistent with the predictions of the turbulent core model of self-gravitating, magnetized (with Alfvén Mach number m{sub A} ∼ 1) and virialized cores that are bounded by the high pressures of their surrounding clumps. However, in the most massive cores, with masses up to ∼60 M {sub ☉}, our results suggest that moderately enhanced magnetic fields (so that m{sub A} ≅ 0.3) may be needed for the structures to be in virial and pressure equilibrium. Magnetically regulated core formation may thus be important in controlling the formation of massive cores, inhibiting their fragmentation, and thus helping to establish the stellar IMF.

  18. Massive Conformal Gravity

    International Nuclear Information System (INIS)

    Faria, F. F.

    2014-01-01

    We construct a massive theory of gravity that is invariant under conformal transformations. The massive action of the theory depends on the metric tensor and a scalar field, which are considered the only field variables. We find the vacuum field equations of the theory and analyze its weak-field approximation and Newtonian limit.

  19. On the Ultimate Fate of Massive Neutron Stars in an Ever Expanding Universe

    Science.gov (United States)

    Hujeirat, Ahmad A.

    2018-01-01

    General theory of relativity predicts the central densities of massive neutron stars (-MANs) to be much larger than the nuclear density. In the absence of energy production, the lifetimes of MANs should be shorter that their low-mass counterparts. Yet neither black holes nor neutron stars, whose masses are between two and five solar masses have ever been observed. Also, it is not clear what happened to the old MANs that were created through the collapse of first generation of stars shortly after the Big Bang. In this article, it is argued that MANs must end as completely invisible objects, whose cores are made of incompressible quark-gluon-superfluids and that their effective masses must have doubled through the injection of dark energy by a universal scalar field at the background of supranuclear density. It turns out that recent glitch observations of pulsars and young neutron star systems and data from particle collisions at the LHC and RHIC are in line with the presen! t scenario.

  20. Complications of cesarean delivery in the massively obese parturient.

    Science.gov (United States)

    Alanis, Mark C; Villers, Margaret S; Law, Tameeka L; Steadman, Elizabeth M; Robinson, Christopher J

    2010-09-01

    The objective of the study was to determine predictors of cesarean delivery morbidity associated with massive obesity. This was an institutional review board-approved retrospective study of massively obese women (body mass index, > or = 50 kg/m(2)) undergoing cesarean delivery. Bivariable and multivariable analyses were used to assess the strength of association between wound complication and various predictors. Fifty-eight of 194 patients (30%) had a wound complication. Most (90%) were wound disruptions, and 86% were diagnosed after hospital discharge (median postoperative day, 8.5; interquartile range, 6-12). Subcutaneous drains and smoking, but not labor or ruptured membranes, were independently associated with wound complication after controlling for various confounders. Vertical abdominal incisions were associated with increased operative time, blood loss, and vertical hysterotomy. Women with a body mass index > or = 50 kg/m(2) have a much greater risk for cesarean wound complications than previously reported. Avoidance of subcutaneous drains and increased use of transverse abdominal wall incisions should be considered in massively obese parturients to reduce operative morbidity. Published by Mosby, Inc.

  1. The Red MSX Source Survey: The Massive Young Stellar Population of Our Galaxy

    Science.gov (United States)

    Lumsden, S. L.; Hoare, M. G.; Urquhart, J. S.; Oudmaijer, R. D.; Davies, B.; Mottram, J. C.; Cooper, H. D. B.; Moore, T. J. T.

    2013-09-01

    We present the Red MSX Source survey, the largest statistically selected catalog of young massive protostars and H II regions to date. We outline the construction of the catalog using mid- and near-infrared color selection. We also discuss the detailed follow up work at other wavelengths, including higher spatial resolution data in the infrared. We show that within the adopted selection bounds we are more than 90% complete for the massive protostellar population, with a positional accuracy of the exciting source of better than 2 arcsec. We briefly summarize some of the results that can be obtained from studying the properties of the objects in the catalog as a whole; we find evidence that the most massive stars form: (1) preferentially nearer the Galactic center than the anti-center; (2) in the most heavily reddened environments, suggestive of high accretion rates; and (3) from the most massive cloud cores.

  2. THE RED MSX SOURCE SURVEY: THE MASSIVE YOUNG STELLAR POPULATION OF OUR GALAXY

    International Nuclear Information System (INIS)

    Lumsden, S. L.; Hoare, M. G.; Oudmaijer, R. D.; Cooper, H. D. B.; Urquhart, J. S.; Davies, B.; Moore, T. J. T.; Mottram, J. C.

    2013-01-01

    We present the Red MSX Source survey, the largest statistically selected catalog of young massive protostars and H II regions to date. We outline the construction of the catalog using mid- and near-infrared color selection. We also discuss the detailed follow up work at other wavelengths, including higher spatial resolution data in the infrared. We show that within the adopted selection bounds we are more than 90% complete for the massive protostellar population, with a positional accuracy of the exciting source of better than 2 arcsec. We briefly summarize some of the results that can be obtained from studying the properties of the objects in the catalog as a whole; we find evidence that the most massive stars form: (1) preferentially nearer the Galactic center than the anti-center; (2) in the most heavily reddened environments, suggestive of high accretion rates; and (3) from the most massive cloud cores

  3. THE RED MSX SOURCE SURVEY: THE MASSIVE YOUNG STELLAR POPULATION OF OUR GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Lumsden, S. L.; Hoare, M. G.; Oudmaijer, R. D.; Cooper, H. D. B. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Urquhart, J. S. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, Bonn (Germany); Davies, B.; Moore, T. J. T. [Astrophysics Research Institute, Liverpool John Moores University, Liverpool L3 5RF (United Kingdom); Mottram, J. C. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)

    2013-09-01

    We present the Red MSX Source survey, the largest statistically selected catalog of young massive protostars and H II regions to date. We outline the construction of the catalog using mid- and near-infrared color selection. We also discuss the detailed follow up work at other wavelengths, including higher spatial resolution data in the infrared. We show that within the adopted selection bounds we are more than 90% complete for the massive protostellar population, with a positional accuracy of the exciting source of better than 2 arcsec. We briefly summarize some of the results that can be obtained from studying the properties of the objects in the catalog as a whole; we find evidence that the most massive stars form: (1) preferentially nearer the Galactic center than the anti-center; (2) in the most heavily reddened environments, suggestive of high accretion rates; and (3) from the most massive cloud cores.

  4. Signature of a Newborn Black Hole from the Collapse of a Supra-massive Millisecond Magnetar

    Science.gov (United States)

    Chen, Wei; Xie, Wei; Lei, Wei-Hua; Zou, Yuan-Chuan; Lü, Hou-Jun; Liang, En-Wei; Gao, He; Wang, Ding-Xiong

    2017-11-01

    An X-ray plateau followed by a steep decay (“internal plateau”) has been observed in both long and short gamma-ray burst (GRBs), implying that a millisecond magnetar operates in some GRBs. The sharp decay at the end of the plateau, marking the abrupt cessation of the magnetar’s central engine, has been considered the collapse of a supra-massive magnetar into a black hole (BH) when it spins down. If this “internal plateau” is indeed evidence of a magnetar central engine, the natural expectation in some candidates would be a signature from the newborn BH. In this work, we find that GRB 070110 is a particular case which shows a small X-ray bump following its “internal plateau.” We interpret the plateau as a spin-down supra-massive magnetar and the X-ray bump as fallback BH accretion. This indicates that a newborn BH is likely active in some GRBs. Therefore, GRB 070110-like events may provide further support to the magnetar central engine model and enable us to investigate the properties of the magnetar as well as the newborn BH.

  5. Massive gravity from bimetric gravity

    International Nuclear Information System (INIS)

    Baccetti, Valentina; Martín-Moruno, Prado; Visser, Matt

    2013-01-01

    We discuss the subtle relationship between massive gravity and bimetric gravity, focusing particularly on the manner in which massive gravity may be viewed as a suitable limit of bimetric gravity. The limiting procedure is more delicate than currently appreciated. Specifically, this limiting procedure should not unnecessarily constrain the background metric, which must be externally specified by the theory of massive gravity itself. The fact that in bimetric theories one always has two sets of metric equations of motion continues to have an effect even in the massive gravity limit, leading to additional constraints besides the one set of equations of motion naively expected. Thus, since solutions of bimetric gravity in the limit of vanishing kinetic term are also solutions of massive gravity, but the contrary statement is not necessarily true, there is no complete continuity in the parameter space of the theory. In particular, we study the massive cosmological solutions which are continuous in the parameter space, showing that many interesting cosmologies belong to this class. (paper)

  6. A FEATURE MOVIE OF SiO EMISSION 20-100 AU FROM THE MASSIVE YOUNG STELLAR OBJECT ORION SOURCE I

    International Nuclear Information System (INIS)

    Matthews, L. D.; Greenhill, L. J.; Goddi, C.; Humphreys, E. M. L.; Chandler, C. J.; Kunz, M. W.

    2010-01-01

    We present multi-epoch Very Long Baseline Array imaging of the 28 SiO v = 1 and v = 2, J = 1-0 maser emission toward the massive young stellar object (YSO) Orion Source I. Both SiO transitions were observed simultaneously with an angular resolution of ∼0.5 mas (∼0.2 AU for d = 414 pc) and a spectral resolution of ∼0.2 km s -1 . Here we explore the global properties and kinematics of the emission through two 19-epoch animated movies spanning 21 months (from 2001 March 19 to 2002 December 10). These movies provide the most detailed view to date of the dynamics and temporal evolution of molecular material within ∼20-100 AU of a massive (∼>8 M sun ) YSO. As in previous studies, we find that the bulk of the SiO masers surrounding Source I lie in an X-shaped locus; the emission in the south and east arms is predominantly blueshifted, and emission in the north and west is predominantly redshifted. In addition, bridges of intermediate-velocity emission are observed connecting the red and blue sides of the emission distribution. We have measured proper motions of over 1000 individual maser features and found that these motions are characterized by a combination of radially outward migrations along the four main maser-emitting arms and motions tangent to the intermediate-velocity bridges. We interpret the SiO masers as arising from a wide-angle bipolar wind emanating from a rotating, edge-on disk. The detection of maser features along extended, curved filaments suggests that magnetic fields may play a role in launching and/or shaping the wind. Our observations appear to support a picture in which stars with masses as high as at least 8 M sun form via disk-mediated accretion. However, we cannot yet rule out that the Source I disk may have been formed or altered following a recent close encounter.

  7. The evolution of massive stars

    International Nuclear Information System (INIS)

    Loore, C. de

    1980-01-01

    The evolution of stars with masses between 15 M 0 and 100 M 0 is considered. Stars in this mass range lose a considerable fraction of their matter during their evolution. The treatment of convection, semi-convection and the influence of mass loss by stellar winds at different evolutionary phases are analysed as well as the adopted opacities. Evolutionary sequences computed by various groups are examined and compared with observations, and the advanced evolution of a 15 M 0 and a 25 M 0 star from zero-age main sequence (ZAMS) through iron collapse is discussed. The effect of centrifugal forces on stellar wind mass loss and the influence of rotation on evolutionary models is examined. As a consequence of the outflow of matter deeper layers show up and when the mass loss rates are large enough layers with changed composition, due to interior nuclear reactions, appear on the surface. The evolution of massive close binaries as well during the phase of mass loss by stellar wind as during the mass exchange and mass loss phase due to Roche lobe overflow is treated in detail, and the value of the parameters governing mass and angular momentum losses are discussed. The problem of the Wolf-Rayet stars, their origin and the possibilities of their production either as single stars or as massive binaries is examined. Finally, the origin of X-ray binaries is discussed and the scenario for the formation of these objects (starting from massive ZAMS close binaries, through Wolf-Rayet binaries leading to OB-stars with a compact companion after a supernova explosion) is reviewed and completed, including stellar wind mass loss. (orig.)

  8. Massively parallel red-black algorithms for x-y-z response matrix equations

    International Nuclear Information System (INIS)

    Hanebutte, U.R.; Laurin-Kovitz, K.; Lewis, E.E.

    1992-01-01

    Recently, both discrete ordinates and spherical harmonic (S n and P n ) methods have been cast in the form of response matrices. In x-y geometry, massively parallel algorithms have been developed to solve the resulting response matrix equations on the Connection Machine family of parallel computers, the CM-2, CM-200, and CM-5. These algorithms utilize two-cycle iteration on a red-black checkerboard. In this work we examine the use of massively parallel red-black algorithms to solve response matric equations in three dimensions. This longer term objective is to utilize massively parallel algorithms to solve S n and/or P n response matrix problems. In this exploratory examination, however, we consider the simple 6 x 6 response matrices that are derivable from fine-mesh diffusion approximations in three dimensions

  9. DETECTION OF BROWN DWARF LIKE OBJECTS IN THE CORE OF NGC 3603

    International Nuclear Information System (INIS)

    Spezzi, Loredana; Beccari, Giacomo; De Marchi, Guido; Andersen, Morten; Young, Erick T.; Paresce, Francesco; Dopita, Michael A.; Panagia, Nino; Bond, Howard E.; Balick, Bruce; Calzetti, Daniela; Carollo, C. Marcella; Disney, Michael J.; Frogel, Jay A.; Hall, Donald N. B.; Holtzman, Jon A.; Kimble, Randy A.; McCarthy, Patrick J.; O'Connell, Robert W.; Ryan, Russell E. Jr

    2011-01-01

    We used near-infrared data obtained with the Wide Field Camera 3 on the Hubble Space Telescope to identify objects having the colors of brown dwarfs (BDs) in the field of the massive galactic cluster NGC 3603. These are identified through a combination of narrow- and medium-band filters which span the J and H bands and are particularly sensitive to the presence of the 1.3-1.5 μm H 2 O molecular band unique to BDs. We provide a calibration of the relationship between effective temperature and color for both field stars and BDs. This photometric method provides effective temperatures for BDs to an accuracy of ±350 K relative to spectroscopic techniques. This accuracy is shown to be not significantly affected by either stellar surface gravity or uncertainties in the interstellar extinction. We identify nine objects having effective temperatures between 1700 and 2200 K, typical of BDs, observed J-band magnitudes in the range 19.5-21.5, and that are strongly clustered toward the luminous core of NGC 3603. However, if these are located at the distance of the cluster, they are far too luminous to be normal BDs. We argue that it is unlikely that these objects are either artifacts of our data set, normal field BDs/M-type giants, or extragalactic contaminants and, therefore, might represent a new class of stars having the effective temperatures of BDs but with luminosities of more massive stars. We explore the interesting scenario in which these objects would be normal stars that have recently tidally ingested a hot Jupiter, the remnants of which are providing a short-lived extended photosphere to the central star. In this case, we would expect them to show the signature of fast rotation.

  10. Gravitational lens effect and pregalactic halo objects

    International Nuclear Information System (INIS)

    Bontz, R.J.

    1979-01-01

    The changes in flux, position, and size of a distant extended (galaxy, etc.) source that result from the gravitational lens action of a massive opaque object are discussed. The flux increase is described by a single function of two parameters. One of these parameters characterizes the strength of the gravitational lens, the other describes the alignment of source and lens object. This function also describes the relative intensity of the images formed by lens. ( A similar formalism is discussed by Bourassa et al. for a point source). The formalism is applied to the problem of the galactic halo. It appears that a massive (10 1 2 M/sub sun/) spherical halo surrounding the visible part of the galaxy is consistent with the observable properties of extragalactic sources

  11. Investigation of the current situation of massive blood transfusion in different surgical departments: a large multicenter study in China

    OpenAIRE

    Sun, Yang; Jin, Zhan-Kui; Xu, Cui-Xiang; Dang, Qian-Li; Zhang, Li-Jie; Chen, Hong-Nan; Song, Yao-Jun; Yang, Jiang-Cun

    2015-01-01

    Objective: This study aims to learn about the current situation of surgical massive blood transfusion of different surgical departments in China’s Tertiary hospitals, which could provide the basis for the formulation of guidelines on massive blood transfusion. Method: A multicenter retrospective research on the application status of blood constituents during massive blood transfusion was conducted and a comparative analyses of survival and length of hospitalization in patients from different ...

  12. Vaidya spacetime in massive gravity's rainbow

    Directory of Open Access Journals (Sweden)

    Yaghoub Heydarzade

    2017-11-01

    Full Text Available In this paper, we will analyze the energy dependent deformation of massive gravity using the formalism of massive gravity's rainbow. So, we will use the Vainshtein mechanism and the dRGT mechanism for the energy dependent massive gravity, and thus analyze a ghost free theory of massive gravity's rainbow. We study the energy dependence of a time-dependent geometry, by analyzing the radiating Vaidya solution in this theory of massive gravity's rainbow. The energy dependent deformation of this Vaidya metric will be performed using suitable rainbow functions.

  13. A circumstellar molecular gas structure associated with the massive young star Cepheus A-HW 2

    Science.gov (United States)

    Torrelles, Jose M.; Rodriguez, Luis F.; Canto, Jorge; Ho, Paul T. P.

    1993-01-01

    We report the detection via VLA-D observations of ammonia of a circumstellar high-density molecular gas structure toward the massive young star related to the object Cepheus A-HW 2, a firm candidate for the powering source of the high-velocity molecular outflow in the region. We suggest that the circumstellar molecular gas structure could be related to the circumstellar disk previously suggested from infrared, H2O, and OH maser observations. We consider as a plausible scenario that the double radio continuum source of HW 2 could represent the ionized inner part of the circumstellar disk, in the same way as proposed to explain the double radio source in L1551. The observed motions in the circumstellar molecular gas can be produced by bound motions (e.g., infall or rotation) around a central mass of about 10-20 solar masses (B0.5 V star or earlier).

  14. MassiveNuS: cosmological massive neutrino simulations

    Science.gov (United States)

    Liu, Jia; Bird, Simeon; Zorrilla Matilla, José Manuel; Hill, J. Colin; Haiman, Zoltán; Madhavacheril, Mathew S.; Petri, Andrea; Spergel, David N.

    2018-03-01

    The non-zero mass of neutrinos suppresses the growth of cosmic structure on small scales. Since the level of suppression depends on the sum of the masses of the three active neutrino species, the evolution of large-scale structure is a promising tool to constrain the total mass of neutrinos and possibly shed light on the mass hierarchy. In this work, we investigate these effects via a large suite of N-body simulations that include massive neutrinos using an analytic linear-response approximation: the Cosmological Massive Neutrino Simulations (MassiveNuS). The simulations include the effects of radiation on the background expansion, as well as the clustering of neutrinos in response to the nonlinear dark matter evolution. We allow three cosmological parameters to vary: the neutrino mass sum Mν in the range of 0–0.6 eV, the total matter density Ωm, and the primordial power spectrum amplitude As. The rms density fluctuation in spheres of 8 comoving Mpc/h (σ8) is a derived parameter as a result. Our data products include N-body snapshots, halo catalogues, merger trees, ray-traced galaxy lensing convergence maps for four source redshift planes between zs=1–2.5, and ray-traced cosmic microwave background lensing convergence maps. We describe the simulation procedures and code validation in this paper. The data are publicly available at http://columbialensing.org.

  15. Asymptotically warped anti-de Sitter spacetimes in topologically massive gravity

    International Nuclear Information System (INIS)

    Henneaux, Marc; Martinez, Cristian; Troncoso, Ricardo

    2011-01-01

    Asymptotically warped AdS spacetimes in topologically massive gravity with negative cosmological constant are considered in the case of spacelike stretched warping, where black holes have been shown to exist. We provide a set of asymptotic conditions that accommodate solutions in which the local degree of freedom (the ''massive graviton'') is switched on. An exact solution with this property is explicitly exhibited and possesses a slower falloff than the warped AdS black hole. The boundary conditions are invariant under the semidirect product of the Virasoro algebra with a u(1) current algebra. We show that the canonical generators are integrable and finite. When the graviton is not excited, our analysis is compared and contrasted with earlier results obtained through the covariant approach to conserved charges. In particular, we find agreement with the conserved charges of the warped AdS black holes as well as with the central charges in the algebra.

  16. Holographically viable extensions of topologically massive and minimal massive gravity?

    Science.gov (United States)

    Altas, Emel; Tekin, Bayram

    2016-01-01

    Recently [E. Bergshoeff et al., Classical Quantum Gravity 31, 145008 (2014)], an extension of the topologically massive gravity (TMG) in 2 +1 dimensions, dubbed as minimal massive gravity (MMG), which is free of the bulk-boundary unitarity clash that inflicts the former theory and all the other known three-dimensional theories, was found. Field equations of MMG differ from those of TMG at quadratic terms in the curvature that do not come from the variation of an action depending on the metric alone. Here we show that MMG is a unique theory and there does not exist a deformation of TMG or MMG at the cubic and quartic order (and beyond) in the curvature that is consistent at the level of the field equations. The only extension of TMG with the desired bulk and boundary properties having a single massive degree of freedom is MMG.

  17. Molecular Cloud Structures and Massive Star Formation in N159

    Science.gov (United States)

    Nayak, O.; Meixner, M.; Fukui, Y.; Tachihara, K.; Onishi, T.; Saigo, K.; Tokuda, K.; Harada, R.

    2018-02-01

    The N159 star-forming region is one of the most massive giant molecular clouds (GMCs) in the Large Magellanic Cloud (LMC). We show the 12CO, 13CO, CS molecular gas lines observed with ALMA in N159 west (N159W) and N159 east (N159E). We relate the structure of the gas clumps to the properties of 24 massive young stellar objects (YSOs) that include 10 newly identified YSOs based on our search. We use dendrogram analysis to identify properties of the molecular clumps, such as flux, mass, linewidth, size, and virial parameter. We relate the YSO properties to the molecular gas properties. We find that the CS gas clumps have a steeper size–linewidth relation than the 12CO or 13CO gas clumps. This larger slope could potentially occur if the CS gas is tracing shocks. The virial parameters of the 13CO gas clumps in N159W and N159E are low (<1). The threshold for massive star formation in N159W is 501 M ⊙ pc‑2, and the threshold for massive star formation in N159E is 794 M ⊙ pc‑2. We find that 13CO is more photodissociated in N159E than N159W. The most massive YSO in N159E has cleared out a molecular gas hole in its vicinity. All the massive YSO candidates in N159E have a more evolved spectral energy distribution type in comparison to the YSO candidates in N159W. These differences lead us to conclude that the giant molecular cloud complex in N159E is more evolved than the giant molecular cloud complex in N159W.

  18. Cardiopulmonary Exercise Testing in Patients Following Massive and Submassive Pulmonary Embolism.

    Science.gov (United States)

    Albaghdadi, Mazen S; Dudzinski, David M; Giordano, Nicholas; Kabrhel, Christopher; Ghoshhajra, Brian; Jaff, Michael R; Weinberg, Ido; Baggish, Aaron

    2018-03-03

    Little data exist regarding the functional capacity of patients following acute pulmonary embolism. We sought to characterize the natural history of symptom burden, right ventricular (RV) structure and function, and exercise capacity among survivors of massive and submassive pulmonary embolism. Survivors of submassive or massive pulmonary embolism (n=20, age 57±13.3 years, 8/20 female) underwent clinical evaluation, transthoracic echocardiography, and cardiopulmonary exercise testing at 1 and 6 months following hospital discharge. At 1 month, 9/20 (45%) patients had New York Heart Association II or greater symptoms, 13/20 (65%) demonstrated either persistent RV dilation or systolic dysfunction, and 14/20 (70%) had objective exercise impairment as defined by a peak oxygen consumption (V˙O 2 ) of 33, or a pulmonary mechanical limit to exercise at either time point. Similarly, persistent RV dilation or dysfunction was not significantly related to symptom burden or peak V˙O 2 at either time point. Persistent symptoms, abnormalities of RV structure and function, and objective exercise limitation are common among survivors of massive and submassive pulmonary embolism. Functional impairment appears to be attributable to general deconditioning rather than intrinsic cardiopulmonary limitation, suggesting an important role for prescribed exercise rehabilitation as a means toward improved patient outcomes and quality of life. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  19. THE MILKY WAY PROJECT: A STATISTICAL STUDY OF MASSIVE STAR FORMATION ASSOCIATED WITH INFRARED BUBBLES

    International Nuclear Information System (INIS)

    Kendrew, S.; Robitaille, T. P.; Simpson, R.; Lintott, C. J.; Bressert, E.; Povich, M. S.; Sherman, R.; Schawinski, K.; Wolf-Chase, G.

    2012-01-01

    The Milky Way Project citizen science initiative recently increased the number of known infrared bubbles in the inner Galactic plane by an order of magnitude compared to previous studies. We present a detailed statistical analysis of this data set with the Red MSX Source (RMS) catalog of massive young stellar sources to investigate the association of these bubbles with massive star formation. We particularly address the question of massive triggered star formation near infrared bubbles. We find a strong positional correlation of massive young stellar objects (MYSOs) and H II regions with Milky Way Project bubbles at separations of <2 bubble radii. As bubble sizes increase, a statistically significant overdensity of massive young sources emerges in the region of the bubble rims, possibly indicating the occurrence of triggered star formation. Based on numbers of bubble-associated RMS sources, we find that 67% ± 3% of MYSOs and (ultra-)compact H II regions appear to be associated with a bubble. We estimate that approximately 22% ± 2% of massive young stars may have formed as a result of feedback from expanding H II regions. Using MYSO-bubble correlations, we serendipitously recovered the location of the recently discovered massive cluster Mercer 81, suggesting the potential of such analyses for discovery of heavily extincted distant clusters.

  20. THE MILKY WAY PROJECT: A STATISTICAL STUDY OF MASSIVE STAR FORMATION ASSOCIATED WITH INFRARED BUBBLES

    Energy Technology Data Exchange (ETDEWEB)

    Kendrew, S.; Robitaille, T. P. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Simpson, R.; Lintott, C. J. [Department of Astrophysics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Bressert, E. [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Povich, M. S. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Sherman, R. [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Avenue, Chicago, IL 60637 (United States); Schawinski, K. [Yale Center for Astronomy and Astrophysics, Yale University, P.O. Box 208121, New Haven, CT 06520 (United States); Wolf-Chase, G., E-mail: kendrew@mpia.de [Astronomy Department, Adler Planetarium, 1300 S. Lake Shore Drive, Chicago, IL 60605 (United States)

    2012-08-10

    The Milky Way Project citizen science initiative recently increased the number of known infrared bubbles in the inner Galactic plane by an order of magnitude compared to previous studies. We present a detailed statistical analysis of this data set with the Red MSX Source (RMS) catalog of massive young stellar sources to investigate the association of these bubbles with massive star formation. We particularly address the question of massive triggered star formation near infrared bubbles. We find a strong positional correlation of massive young stellar objects (MYSOs) and H II regions with Milky Way Project bubbles at separations of <2 bubble radii. As bubble sizes increase, a statistically significant overdensity of massive young sources emerges in the region of the bubble rims, possibly indicating the occurrence of triggered star formation. Based on numbers of bubble-associated RMS sources, we find that 67% {+-} 3% of MYSOs and (ultra-)compact H II regions appear to be associated with a bubble. We estimate that approximately 22% {+-} 2% of massive young stars may have formed as a result of feedback from expanding H II regions. Using MYSO-bubble correlations, we serendipitously recovered the location of the recently discovered massive cluster Mercer 81, suggesting the potential of such analyses for discovery of heavily extincted distant clusters.

  1. Vector dark energy and high-z massive clusters

    Science.gov (United States)

    Carlesi, Edoardo; Knebe, Alexander; Yepes, Gustavo; Gottlöber, Stefan; Jiménez, Jose Beltrán.; Maroto, Antonio L.

    2011-12-01

    The detection of extremely massive clusters at z > 1 such as SPT-CL J0546-5345, SPT-CL J2106-5844 and XMMU J2235.3-2557 has been considered by some authors as a challenge to the standard Λ cold dark matter cosmology. In fact, assuming Gaussian initial conditions, the theoretical expectation of detecting such objects is as low as ≤1 per cent. In this paper we discuss the probability of the existence of such objects in the light of the vector dark energy paradigm, showing by means of a series of N-body simulations that chances of detection are substantially enhanced in this non-standard framework.

  2. The Final Stages of Massive Star Evolution and Their Supernovae

    Science.gov (United States)

    Heger, Alexander

    In this chapter I discuss the final stages in the evolution of massive stars - stars that are massive enough to burn nuclear fuel all the way to iron group elements in their core. The core eventually collapses to form a neutron star or a black hole when electron captures and photo-disintegration reduce the pressure support to an extent that it no longer can hold up against gravity. The late burning stages of massive stars are a rich subject by themselves, and in them many of the heavy elements in the universe are first generated. The late evolution of massive stars strongly depends on their mass, and hence can be significantly effected by mass loss due to stellar winds and episodic mass loss events - a critical ingredient that we do not know as well as we would like. If the star loses all the hydrogen envelope, a Type I supernova results, if it does not, a Type II supernova is observed. Whether the star makes neutron star or a black hole, or a neutron star at first and a black hole later, and how fast they spin largely affects the energetics and asymmetry of the observed supernova explosion. Beyond photon-based astronomy, other than the sun, a supernova (SN 1987) has been the only object in the sky we ever observed in neutrinos, and supernovae may also be the first thing we will ever see in gravitational wave detectors like LIGO. I conclude this chapter reviewing the deaths of the most massive stars and of Population III stars.

  3. The TESIS Project: Revealing Massive Early-Type Galaxies at z > 1

    Science.gov (United States)

    Saracco, P.; Longhetti, M.; Severgnini, P.; Della Ceca, R.; Braito, V.; Bender, R.; Drory, N.; Feulner, G.; Hopp, U.; Mannucci, F.; Maraston, C.

    How and when present-day massive early-type galaxies built up and what type of evolution has characterized their growth (star formation and/or merging) still remain open issues. The different competing scenarios of galaxy formation predict much different properties of early-type galaxies at z > 1. The "monolithic" collapse predicts that massive spheroids formed at high redshift (z > 2.5-3) and that their comoving density is constant at z 1, their comoving density decreases from z = 0 to z ~ 1.5 and they should experience their last burst of star formation at z 1 can be probed observationally once a well defined sample of massive early-types at z > 1 is available. We are constructing such a sample through a dedicated near-IR very low resolution (λ/Δλ≃50) spectroscopic survey (TNG EROs Spectroscopic Identification Survey, TESIS, [6]) of a complete sample of 30 bright (K < 18.5) Extremely Red Objects (EROs).

  4. How practitioners approach gameplay requirements? An exploration into the context of massive multiplayer online role-playing games

    NARCIS (Netherlands)

    Daneva, Maia; Lutz, Robyn

    2014-01-01

    Gameplay requirements are central to game development. In the business context of massive multiplayer online role-playing games (MMOGs) where game companies' revenues rely on players' monthly subscriptions, gameplay is also recognized as the key to player retention. However, information on what

  5. Temporary interventional pneumonectomy used as an emergency treatment for acute massive pulmonary embolism: the initial experimental results

    International Nuclear Information System (INIS)

    Fan Yong; Liu Yang; Wu Qi; Li Ping; Tian Jing; Bao Guijun; He Nengshu

    2009-01-01

    Objective: To evaluate regional airway obstruction with balloon catheter in stabilizing the vital signs in experimental animals suffered from acute massive pulmonary embolism. Methods: Pulmonary embolism of right lung artery by using auto-blood clots or detachable latex balloons was established in 27 healthy sheep. When the blood oxygen saturation decreased by 25% compared to that before the procedure, the placement of balloon catheter in corresponding right main bronchus was carried out in 18 sheep (study group). Five sheep were used as control group. The blood oxygen saturation in the remaining four sheep did not reach the intervention level. The pulmonary arterial pressure, the peripheral arterial pressure, the central venous pressure, the heart rate, the blood oxygen saturation, the arterial partial pressure of oxygen as well as of carbon dioxide were invasively determined. Results: The experimental model of acute massive pulmonary embolism was successfully established in 23 sheep. After the establishment of pulmonary embolism, increased heart rate, tachypnea, a decrease of ≥ 25% in blood oxygen saturation within 30 minutes and a rise in pulmonary arterial pressure were detected. After the placement of balloon catheter in study group, a reduction of the pulmonary arterial pressure and an elevation of the blood oxygen saturation as well as the arterial partial pressure of oxygen rose were observed.The difference between study group and control group was statistically significant (P<0.05). Conclusion: The result of this animal experiment indicates that obstruction of airway with balloon can be served as a first aid for acute massive pulmonary embolism, which can stabilizes the animal's vital signs and, therefore, can help gain precious time for the follow-up thrombolysis treatment. (authors)

  6. Massive Supergravity and Deconstruction

    CERN Document Server

    Gregoire, T; Shadmi, Y; Gregoire, Thomas; Schwartz, Matthew D; Shadmi, Yael

    2004-01-01

    We present a simple superfield Lagrangian for massive supergravity. It comprises the minimal supergravity Lagrangian with interactions as well as mass terms for the metric superfield and the chiral compensator. This is the natural generalization of the Fierz-Pauli Lagrangian for massive gravity which comprises mass terms for the metric and its trace. We show that the on-shell bosonic and fermionic fields are degenerate and have the appropriate spins: 2, 3/2, 3/2 and 1. We then study this interacting Lagrangian using goldstone superfields. We find that a chiral multiplet of goldstones gets a kinetic term through mixing, just as the scalar goldstone does in the non-supersymmetric case. This produces Planck scale (Mpl) interactions with matter and all the discontinuities and unitarity bounds associated with massive gravity. In particular, the scale of strong coupling is (Mpl m^4)^1/5, where m is the multiplet's mass. Next, we consider applications of massive supergravity to deconstruction. We estimate various qu...

  7. COLA with massive neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Bill S.; Winther, Hans A.; Koyama, Kazuya, E-mail: bill.wright@port.ac.uk, E-mail: hans.winther@port.ac.uk, E-mail: kazuya.koyama@port.ac.uk [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, Hampshire, PO1 3FX (United Kingdom)

    2017-10-01

    The effect of massive neutrinos on the growth of cold dark matter perturbations acts as a scale-dependent Newton's constant and leads to scale-dependent growth factors just as we often find in models of gravity beyond General Relativity. We show how to compute growth factors for ΛCDM and general modified gravity cosmologies combined with massive neutrinos in Lagrangian perturbation theory for use in COLA and extensions thereof. We implement this together with the grid-based massive neutrino method of Brandbyge and Hannestad in MG-PICOLA and compare COLA simulations to full N -body simulations of ΛCDM and f ( R ) gravity with massive neutrinos. Our implementation is computationally cheap if the underlying cosmology already has scale-dependent growth factors and it is shown to be able to produce results that match N -body to percent level accuracy for both the total and CDM matter power-spectra up to k ∼< 1 h /Mpc.

  8. Polarized bow shocks reveal features of the winds and environments of massive stars

    Science.gov (United States)

    Shrestha, Manisha

    2018-01-01

    Massive stars strongly affect their surroundings through their energetic stellar winds and deaths as supernovae. The bow shock structures created by fast-moving massive stars contain important information about the winds and ultimate fates of these stars as well as their local interstellar medium (ISM). Since bow shocks are aspherical, the light scattered in the dense shock material becomes polarized. Analyzing this polarization reveals details of the bow shock geometry as well as the composition, velocity, density, and albedo of the scattering material. With these quantities, we can constrain the properties of the stellar wind and thus the evolutionary state of the star, as well as the dust composition of the local ISM.In my dissertation research, I use a Monte Carlo radiative transfer code that I optimized to simulate the polarization signatures produced by both resolved and unresolved stellar wind bow shocks (SWBS) illuminated by a central star and by shock emission. I derive bow shock shapes and densities from published analytical calculations and smooth particle hydrodynamic (SPH) models. In the case of the analytical SWBS and electron scattering, I find that higher optical depths produce higher polarization and position angle rotations at specific viewing angles compared to theoretical predictions for low optical depths. This is due to the geometrical properties of the bow shock combined with multiple scattering effects. For dust scattering, the polarization signature is strongly affected by wavelength, dust grain properties, and viewing angle. The behavior of the polarization as a function of wavelength in these cases can distinguish among different dust models for the local ISM. In the case of SPH density structures, I investigate how the polarization changes as a function of the evolutionary phase of the SWBS. My dissertation compares these simulations with polarization data from Betelgeuse and other massive stars with bow shocks. I discuss the

  9. Can we constrain the maximum value for the spin parameter of the super-massive objects in galactic nuclei without knowing their actual nature?

    International Nuclear Information System (INIS)

    Bambi, Cosimo

    2011-01-01

    In 4-dimensional General Relativity, black holes are described by the Kerr solution and are subject to the bound |a * |≤1, where a * is the black hole spin parameter. If current black hole candidates are not the black holes predicted in General Relativity, this bound does not hold and a * might exceed 1. In this Letter, I relax the Kerr black hole hypothesis and I find that the value of the spin parameter of the super-massive black hole candidates in galactic nuclei cannot be higher than about 1.2. A higher spin parameter would not be consistent with a radiative efficiency η>0.15, as observed at least for the most luminous AGN. While a rigorous proof is lacking, I conjecture that the bound |a * |≤1.2 is independent of the exact nature of these objects.

  10. ON THE DEARTH OF COMPACT, MASSIVE, RED SEQUENCE GALAXIES IN THE LOCAL UNIVERSE

    International Nuclear Information System (INIS)

    Taylor, Edward N.; Franx, Marijn; Brinchmann, Jarle; Glazebrook, Karl; Van der Wel, Arjen; Van Dokkum, Pieter G

    2010-01-01

    We set out to test the claim that the recently identified population of compact, massive, and quiescent galaxies at z ∼ 2.3 must undergo significant size evolution to match the properties of galaxies found in the local universe. Using data from the Sloan Digital Sky Survey (SDSS; Data Release 7), we have conducted a search for local red sequence galaxies with sizes and masses comparable to those found at z ∼ 2.3. The SDSS spectroscopic target selection algorithm excludes high surface brightness objects; we show that this makes incompleteness a concern for such massive, compact galaxies, particularly for low redshifts (z ∼ * >10 10.7 M sun (∼5 x 10 10 M sun ) red sequence galaxies at 0.066 spec 5000. This result cannot be explained by incompleteness: in the 0.066 75% complete for galaxies with the sizes and masses seen at high redshift, although for the very smallest galaxies it may be as low as ∼20%. In order to confirm that the absence of such compact massive galaxies in SDSS is not produced by spectroscopic selection effects, we have also looked for such galaxies in the basic SDSS photometric catalog, using photometric redshifts. While we do find signs of a slight bias against massive, compact galaxies, this analysis suggests that the SDSS spectroscopic sample is missing at most a few objects in the regime we consider. Accepting the high-redshift results, it is clear that massive galaxies must undergo significant structural evolution over z ∼< 2 in order to match the population seen in the local universe. Our results suggest that a highly stochastic mechanism (e.g., major mergers) cannot be the primary driver of this strong size evolution.

  11. Measurement and Analysis of Olfactory Responses with the Aim of Establishing an Objective Diagnostic Method for Central Olfactory Disorders

    Science.gov (United States)

    Uno, Tominori; Wang, Li-Qun; Miwakeichi, Fumikazu; Tonoike, Mitsuo; Kaneda, Teruo

    In order to establish a new diagnostic method for central olfactory disorders and to identify objective indicators, we measured and analyzed brain activities in the parahippocampal gyrus and uncus, region of responsibility for central olfactory disorders. The relationship between olfactory stimulation and brain response at region of responsibility can be examined in terms of fitted responses (FR). FR in these regions may be individual indicators of changes in brain olfactory responses. In the present study, in order to non-invasively and objectively measure olfactory responses, an odor oddball task was conducted on four healthy volunteers using functional magnetic resonance imaging (fMRI) and a odorant stimulator with blast-method. The results showed favorable FR and activation in the parahippocampal gyrus or uncus in all subjects. In some subjects, both the parahippocampal gyrus and uncus were activated. Furthermore, activation was also confirmed in the cingulate gyrus, middle frontal gyrus, precentral gyrus, postcentral gyrus, superior temporal gyrus and insula. The hippocampus and uncus are known to be involved in the olfactory disorders associated with early-stage Alzheimer's disease and other olfactory disorders. In the future, it will be necessary to further develop the present measurement and analysis method to clarify the relationship between central olfactory disorders and brain activities and establish objective indicators that are useful for diagnosis.

  12. A parsec-scale optical jet from a massive young star in the Large Magellanic Cloud.

    Science.gov (United States)

    McLeod, Anna F; Reiter, Megan; Kuiper, Rolf; Klaassen, Pamela D; Evans, Christopher J

    2018-02-15

    Highly collimated parsec-scale jets, which are generally linked to the presence of an accretion disk, are commonly observed in low-mass young stellar objects. In the past two decades, a few of these jets have been directly (or indirectly) observed from higher-mass (larger than eight solar masses) young stellar objects, adding to the growing evidence that disk-mediated accretion also occurs in high-mass stars, the formation mechanism of which is still poorly understood. Of the observed jets from massive young stars, none is in the optical regime (massive young stars are typically highly obscured by their natal material), and none is found outside of the Milky Way. Here we report observations of HH 1177, an optical ionized jet that originates from a massive young stellar object located in the Large Magellanic Cloud. The jet is highly collimated over its entire measured length of at least ten parsecs and has a bipolar geometry. The presence of a jet indicates ongoing, disk-mediated accretion and, together with the high degree of collimation, implies that this system is probably formed through a scaled-up version of the formation mechanism of low-mass stars. We conclude that the physics that govern jet launching and collimation is independent of stellar mass.

  13. A parsec-scale optical jet from a massive young star in the Large Magellanic Cloud

    Science.gov (United States)

    McLeod, Anna F.; Reiter, Megan; Kuiper, Rolf; Klaassen, Pamela D.; Evans, Christopher J.

    2018-02-01

    Highly collimated parsec-scale jets, which are generally linked to the presence of an accretion disk, are commonly observed in low-mass young stellar objects. In the past two decades, a few of these jets have been directly (or indirectly) observed from higher-mass (larger than eight solar masses) young stellar objects, adding to the growing evidence that disk-mediated accretion also occurs in high-mass stars, the formation mechanism of which is still poorly understood. Of the observed jets from massive young stars, none is in the optical regime (massive young stars are typically highly obscured by their natal material), and none is found outside of the Milky Way. Here we report observations of HH 1177, an optical ionized jet that originates from a massive young stellar object located in the Large Magellanic Cloud. The jet is highly collimated over its entire measured length of at least ten parsecs and has a bipolar geometry. The presence of a jet indicates ongoing, disk-mediated accretion and, together with the high degree of collimation, implies that this system is probably formed through a scaled-up version of the formation mechanism of low-mass stars. We conclude that the physics that govern jet launching and collimation is independent of stellar mass.

  14. Massive Black Holes and Galaxies

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Evidence has been accumulating for several decades that many galaxies harbor central mass concentrations that may be in the form of black holes with masses between a few million to a few billion time the mass of the Sun. I will discuss measurements over the last two decades, employing adaptive optics imaging and spectroscopy on large ground-based telescopes that prove the existence of such a massive black hole in the Center of our Milky Way, beyond any reasonable doubt. These data also provide key insights into its properties and environment. Most recently, a tidally disrupting cloud of gas has been discovered on an almost radial orbit that reached its peri-distance of ~2000 Schwarzschild radii in 2014, promising to be a valuable tool for exploring the innermost accretion zone. Future interferometric studies of the Galactic Center Black hole promise to be able to test gravity in its strong field limit.

  15. Hot stars in young massive clusters: Mapping the current Galactic metallicity

    Science.gov (United States)

    de la Fuente, Diego; Najarro, Francisco; Davies, Ben; Trombley, Christine; Figer, Donald F.; Herrero, Artemio

    2013-06-01

    Young Massive Clusters (YMCs) with ages guarantee that these objects present the same chemical composition than the surrounding environment where they are recently born. Finally, the YMCs host very massive stars whose extreme luminosities allow to accomplish detailed spectroscopic analyses even in the most distant regions of the Milky Way. Our group has carried out ISAAC/VLT spectroscopic observations of hot massive stars belonging to several YMCs in different locations around the Galactic disk. As a result, high signal-to-noise, near-infrared spectra of dozens of blue massive stars (including many OB supergiants, Wolf-Rayet stars and a B hypergiant) have been obtained. These data are fully reduced, and NLTE spherical atmosphere modeling is in process. Several line diagnostics will be combined in order to calculate metal abundances accurately for each cluster. The diverse locations of the clusters will allow us to draw a two-dimensional chemical map of the Galactic disk for the first time. The study of the radial and azimuthal variations of elemental abundances will be crucial for understanding the chemical evolution of the Milky Way. Particularly, the ratio between Fe-peak and alpha elements will constitute a powerful tool to investigate the past stellar populations that originated the current Galactic chemistry.

  16. Multiscale analyses on a massive immigration process of Sogatella furcifera (Horváth) in south-central China: influences of synoptic-scale meteorological conditions and topography

    Science.gov (United States)

    Wu, Qiu-Lin; Westbrook, John K.; Hu, Gao; Lu, Ming-Hong; Liu, Wan-Cai; Sword, Gregory A.; Zhai, Bao-Ping

    2018-04-01

    Mass landings of migrating white-backed planthopper, Sogatella furcifera (Horváth), can lead to severe outbreaks that cause heavy losses for rice production in East Asia. South-central China is the main infestation area on the annual migration loop of S. furcifera between the northern Indo-China Peninsula and mainland China; however, rice planthopper species are not able to survive in this region over winter. In this study, a trajectory analysis of movements from population source areas and a spatiotemporal dynamic analysis of mesoscale and synoptic weather conditions from 7 to 10 May 2012 were conducted using the weather research and forecasting (WRF) model to identify source areas of immigrants and determine how weather and topographic terrain influence insect landing. A sensitivity experiment was conducted with reduced topography using the WRF model to explain the associations among rainfall, topography, and light-trap catches of S. furcifera. The trajectory modeling results suggest that the source areas of S. furcifera immigrants into south-central China from 8 to 10 May were mainly southern Guangxi, northern Vietnam, and north-central Vietnam. The appearance of enormous catches of immigrant S. furcifera coincided with a period of rainstorms. The formation of transporting southerly winds was strongly associated with the topographic terrain. Additionally, the rainfall distribution and intensity over south-central China significantly decreased when topography was reduced in the model and were directly affected by wind circulation, which was associated with mountainous terrain that caused strong convection. This study indicates that migrating populations of S. furcifera were carried by the southwesterly low-level jets and that topographically induced convergent winds, precipitation, low temperatures, and wind shear acted as key factors that led to massive landings.

  17. Multiscale analyses on a massive immigration process of Sogatella furcifera (Horváth) in south-central China: influences of synoptic-scale meteorological conditions and topography.

    Science.gov (United States)

    Wu, Qiu-Lin; Westbrook, John K; Hu, Gao; Lu, Ming-Hong; Liu, Wan-Cai; Sword, Gregory A; Zhai, Bao-Ping

    2018-04-30

    Mass landings of migrating white-backed planthopper, Sogatella furcifera (Horváth), can lead to severe outbreaks that cause heavy losses for rice production in East Asia. South-central China is the main infestation area on the annual migration loop of S. furcifera between the northern Indo-China Peninsula and mainland China; however, rice planthopper species are not able to survive in this region over winter. In this study, a trajectory analysis of movements from population source areas and a spatiotemporal dynamic analysis of mesoscale and synoptic weather conditions from 7 to 10 May 2012 were conducted using the weather research and forecasting (WRF) model to identify source areas of immigrants and determine how weather and topographic terrain influence insect landing. A sensitivity experiment was conducted with reduced topography using the WRF model to explain the associations among rainfall, topography, and light-trap catches of S. furcifera. The trajectory modeling results suggest that the source areas of S. furcifera immigrants into south-central China from 8 to 10 May were mainly southern Guangxi, northern Vietnam, and north-central Vietnam. The appearance of enormous catches of immigrant S. furcifera coincided with a period of rainstorms. The formation of transporting southerly winds was strongly associated with the topographic terrain. Additionally, the rainfall distribution and intensity over south-central China significantly decreased when topography was reduced in the model and were directly affected by wind circulation, which was associated with mountainous terrain that caused strong convection. This study indicates that migrating populations of S. furcifera were carried by the southwesterly low-level jets and that topographically induced convergent winds, precipitation, low temperatures, and wind shear acted as key factors that led to massive landings.

  18. Acute fasting inhibits central caspase-1 activity reducing anxiety-like behavior and increasing novel object and object location recognition.

    Science.gov (United States)

    Towers, Albert E; Oelschlager, Maci L; Patel, Jay; Gainey, Stephen J; McCusker, Robert H; Freund, Gregory G

    2017-06-01

    Inflammation within the central nervous system (CNS) is frequently comorbid with anxiety. Importantly, the pro-inflammatory cytokine most commonly associated with anxiety is IL-1β. The bioavailability and activity of IL-1β are regulated by caspase-1-dependent proteolysis vis-a-vis the inflammasome. Thus, interventions regulating the activation or activity of caspase-1 should reduce anxiety especially in states that foster IL-1β maturation. Male C57BL/6j, C57BL/6j mice treated with the capase-1 inhibitor biotin-YVAD-cmk, caspase-1 knockout (KO) mice and IL-1R1 KO mice were fasted for 24h or allowed ad libitum access to food. Immediately after fasting, caspase-1 activity was measured in brain region homogenates while activated caspase-1 was localized in the brain by immunohistochemistry. Mouse anxiety-like behavior and cognition were tested using the elevated zero maze and novel object/object location tasks, respectively. A 24h fast in mice reduced the activity of caspase-1 in whole brain and in the prefrontal cortex, amygdala, hippocampus, and hypothalamus by 35%, 25%, 40%, 40%, and 40% respectively. A 24h fast also reduced anxiety-like behavior by 40% and increased novel object and object location recognition by 21% and 31%, respectively. IL-1β protein, however, was not reduced in the brain by fasting. ICV administration of YVAD decreased caspase-1 activity in the prefrontal cortex and amygdala by 55%, respectively leading to a 64% reduction in anxiety like behavior. Importantly, when caspase-1 KO or IL1-R1 KO mice are fasted, no fasting-dependent reduction in anxiety-like behavior was observed. Results indicate that fasting decrease anxiety-like behavior and improves memory by a mechanism tied to reducing caspase-1 activity throughout the brain. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Inelastic surface collisions and the desorption of massive molecular ions

    Energy Technology Data Exchange (ETDEWEB)

    Macfarlane, R D [Texas A and M Univ., College Station (USA). Dept. of Chemistry

    1983-01-01

    The interaction of high energy ions in the region of electronic stopping (1 MeV u/sup -1/) stimulates the desorption of massive molecular ions of biomolecules such as insulin. The experimental details of the measurements are given with some examples of application for analytical mass spectrometry. Studies on the role of the incident ion (accelerator beam experiments) are reviewed as well as the contribution of the matrix to the desorption-ionization process. How the electronic relaxation process couples to desorption-ionization is a central question in understanding the overall mechanism of the process.

  20. NGC 1277: A MASSIVE COMPACT RELIC GALAXY IN THE NEARBY UNIVERSE

    Energy Technology Data Exchange (ETDEWEB)

    Trujillo, Ignacio; Vazdekis, Alexandre [Instituto de Astrofísica de Canarias, c/Vía Láctea s/n, E-38205-La Laguna, Tenerife (Spain); Ferré-Mateu, Anna [Subaru Telescope, 650 North A' ohoku Place, Hilo, HI 96720 (United States); Balcells, Marc [Isaac Newton Group of Telescopes, E-38700 Santa Cruz de La Palma, Canary Islands (Spain); Sánchez-Blázquez, Patricia, E-mail: trujillo@iac.es [Departamento de Física Teórica, Universidad Autónoma de Madrid, E-28049, Cantoblanco, Madrid (Spain)

    2014-01-10

    As early as 10 Gyr ago, galaxies with more than 10{sup 11} M {sub ☉} of stars already existed. While most of these massive galaxies must have subsequently transformed through on-going star formation and mergers with other galaxies, a small fraction (≲0.1%) may have survived untouched until today. Searches for such relic galaxies, useful windows to explore the early universe, have been inconclusive to date: galaxies with masses and sizes like those observed at high redshift (M {sub *} ≳ 10{sup 11} M {sub ☉}; R{sub e} ≲ 1.5 kpc) have been found in the local universe, but their stars are far too young for the galaxy to be a relic galaxy. This paper explores the first case of a nearby galaxy, NGC 1277 (at a distance of 73 Mpc in the Perseus galaxy cluster), which fulfills many criteria to be considered a relic galaxy. Using deep optical spectroscopy, we derive the star formation history along the structure of the galaxy: the stellar populations are uniformly old (>10 Gyr) with no evidence for more recent star formation episodes. The metallicity of their stars is super-solar ([Fe/H] = 0.20 ± 0.04 with a smooth decline toward the outer regions) and α-enriched ([α/Fe] = 0.4 ± 0.1). This suggests a very short formation time scale for the bulk of the stars in this galaxy. This object also rotates very fast (V {sub rot} ∼ 300 km s{sup –1}) and has a large central velocity dispersion (σ > 300 km s{sup –1}). NGC 1277 allows the exploration in full detail of properties such as the structure, internal dynamics, metallicity, and initial mass function as they were at ∼10-12 Gyr ago when the first massive galaxies were built.

  1. METHYL CYANIDE OBSERVATIONS TOWARD MASSIVE PROTOSTARS

    Energy Technology Data Exchange (ETDEWEB)

    Rosero, V.; Hofner, P. [Physics Department, New Mexico Tech, 801 Leroy Place, Socorro, NM 87801 (United States); Kurtz, S. [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, Morelia 58090 (Mexico); Bieging, J. [Department of Astronomy and Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Araya, E. D. [Physics Department, Western Illinois University, 1 University Circle, Macomb, IL 61455 (United States)

    2013-07-01

    We report the results of a survey in the CH{sub 3}CN J = 12 {yields} 11 transition toward a sample of massive proto-stellar candidates. The observations were carried out with the 10 m Submillimeter Telescope on Mount Graham, AZ. We detected this molecular line in 9 out of 21 observed sources. In six cases this is the first detection of this transition. We also obtained full beam sampled cross-scans for five sources which show that the lower K-components can be extended on the arcminute angular scale. The higher K-components, however, are always found to be compact with respect to our 36'' beam. A Boltzmann population diagram analysis of the central spectra indicates CH{sub 3}CN column densities of about 10{sup 14} cm{sup -2}, and rotational temperatures above 50 K, which confirms these sources as hot molecular cores. Independent fits to line velocity and width for the individual K-components resulted in the detection of an increasing blueshift with increasing line excitation for four sources. Comparison with mid-infrared (mid-IR) images from the SPITZER GLIMPSE/IRAC archive for six sources show that the CH{sub 3}CN emission is generally coincident with a bright mid-IR source. Our data clearly show that the CH{sub 3}CN J = 12 {yields} 11 transition is a good probe of the hot molecular gas near massive protostars, and provide the basis for future interferometric studies.

  2. Analysis of massive data streams using R and AMIDST

    DEFF Research Database (Denmark)

    Madsen, Anders Læsø; Salmerón, Antonio

    methods able to handle massive data streams based on Bayesian networks technology. All of the developed methods are available through the AMIDST toolbox, implemented in Java 8. We show how the functionality of the AMIDST toolbox can be accessed from R. Available AMIDST objects include variables......, distributions and Bayesian networks, as well as those devoted to inference and learning. The interaction between both platforms relies on the rJava package....

  3. Nonsingular universe in massive gravity's rainbow

    Science.gov (United States)

    Hendi, S. H.; Momennia, M.; Eslam Panah, B.; Panahiyan, S.

    2017-06-01

    One of the fundamental open questions in cosmology is whether we can regard the universe evolution without singularity like a Big Bang or a Big Rip. This challenging subject stimulates one to regard a nonsingular universe in the far past with an arbitrarily large vacuum energy. Considering the high energy regime in the cosmic history, it is believed that Einstein gravity should be corrected to an effective energy dependent theory which could be acquired by gravity's rainbow. On the other hand, employing massive gravity provided us with solutions to some of the long standing fundamental problems of cosmology such as cosmological constant problem and self acceleration of the universe. Considering these aspects of gravity's rainbow and massive gravity, in this paper, we initiate studying FRW cosmology in the massive gravity's rainbow formalism. At first, we show that although massive gravity modifies the FRW cosmology, but it does not itself remove the big bang singularity. Then, we generalize the massive gravity to the case of energy dependent spacetime and find that massive gravity's rainbow can remove the early universe singularity. We bring together all the essential conditions for having a nonsingular universe and the effects of both gravity's rainbow and massive gravity generalizations on such criteria are determined.

  4. Massive propagators in instanton fields

    International Nuclear Information System (INIS)

    Brown, L.S.; Lee, C.

    1978-01-01

    Green's functions for massive spinor and vector particles propagating in a self-dual but otherwise arbitrary non-Abelian gauge field are shown to be completely determined by the corresponding Green's functions of massive scalar particles

  5. Topologically massive supergravity

    Directory of Open Access Journals (Sweden)

    S. Deser

    1983-01-01

    Full Text Available The locally supersymmetric extension of three-dimensional topologically massive gravity is constructed. Its fermionic part is the sum of the (dynamically trivial Rarita-Schwinger action and a gauge-invariant topological term, of second derivative order, analogous to the gravitational one. It is ghost free and represents a single massive spin 3/2 excitation. The fermion-gravity coupling is minimal and the invariance is under the usual supergravity transformations. The system's energy, as well as that of the original topological gravity, is therefore positive.

  6. Blinded by the light: on the relationship between CO first overtone emission and mass accretion rate in massive young stellar objects

    Science.gov (United States)

    Ilee, J. D.; Oudmaijer, R. D.; Wheelwright, H. E.; Pomohaci, R.

    2018-04-01

    To date, there is no explanation as to why disc-tracing CO first overtone (or `bandhead') emission is not a ubiquitous feature in low- to medium-resolution spectra of massive young stellar objects, but instead is only detected toward approximately 25 per cent of their spectra. In this paper, we investigate the hypothesis that only certain mass accretion rates result in detectable bandhead emission in the near infrared spectra of MYSOs. Using an analytic disc model combined with an LTE model of the CO emission, we find that high accretion rates (≳ 10-4 M⊙yr-1) result in large dust sublimation radii, a larger contribution to the K-band continuum from hot dust at the dust sublimation radius, and therefore correspondingly lower CO emission with respect to the continuum. On the other hand, low accretion rates (≲ 10-6 M⊙yr-1) result in smaller dust sublimation radii, a correspondingly smaller emitting area of CO, and thus also lower CO emission with respect to the continuum. In general, moderate accretion rates produce the most prominent, and therefore detectable, CO first overtone emission. We compare our findings to a recent near-infrared spectroscopic survey of MYSOs, finding results consistent with our hypothesis. We conclude that the detection rate of CO bandhead emission in the spectra of MYSOs could be the result of MYSOs exhibiting a range of mass accretion rates, perhaps due to the variable accretion suggested by recent multi-epoch observations of these objects.

  7. Spacetime structure of massive Majorana particles and massive gravitino

    Energy Technology Data Exchange (ETDEWEB)

    Ahluwalia, D.V.; Kirchbach, M. [Theoretical Physics Group, Facultad de Fisica, Universidad Autonoma de Zacatecas, A.P. 600, 98062 Zacatecas (Mexico)

    2003-07-01

    The profound difference between Dirac and Majorana particles is traced back to the possibility of having physically different constructs in the (1/2, 0) 0 (0,1/2) representation space. Contrary to Dirac particles, Majorana-particle propagators are shown to differ from the simple linear {gamma} {mu} p{sub {mu}}, structure. Furthermore, neither Majorana particles, nor their antiparticles can be associated with a well defined arrow of time. The inevitable consequence of this peculiarity is the particle-antiparticle metamorphosis giving rise to neutrinoless double beta decay, on the one side, and enabling spin-1/2 fields to act as gauge fields, gauginos, on the other side. The second part of the lecture notes is devoted to massive gravitino. We argue that a spin measurement in the rest frame for an unpolarized ensemble of massive gravitino, associated with the spinor-vector [(1/2, 0) 0 (0,1/2)] 0 (1/2,1/2) representation space, would yield the results 3/2 with probability one half, and 1/2 with probability one half. The latter is distributed uniformly, i.e. as 1/4, among the two spin-1/2+ and spin-1/2- states of opposite parities. From that we draw the conclusion that the massive gravitino should be interpreted as a particle of multiple spin. (Author)

  8. Search of massive star formation with COMICS

    Science.gov (United States)

    Okamoto, Yoshiko K.

    2004-04-01

    Mid-infrared observations is useful for studies of massive star formation. Especially COMICS offers powerful tools: imaging survey of the circumstellar structures of forming massive stars such as massive disks and cavity structures, mass estimate from spectroscopy of fine structure lines, and high dispersion spectroscopy to census gas motion around formed stars. COMICS will open the next generation infrared studies of massive star formation.

  9. India's manganese nodule mine site in the Central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Banakar, V.K.

    This commentary highlights the activities of massive exploration programme for manganese nodule deposits in the Central Indian Basin located 5 km below the ocean surface and India's claim for mine site development and registration with UNCLOS...

  10. Centrally-administered oxytocin promotes preference for familiar objects at a short delay in ovariectomized female rats.

    Science.gov (United States)

    Madularu, Dan; Athanassiou, Maria; Yee, Jason R; Mumby, Dave G

    2014-11-01

    Oxytocin has been previously associated with social attachment behaviors in various species, however, most studies focused on partner preference in the socially-monogamous prairie vole. In these, oxytocin treatment was shown to promote partner preference, such that females receiving either central or pulsatile peripheral administration would spend more time with a familiar male. This behavioral outcome was blocked by oxytocin receptor antagonist treatment. The aim of the current study was to further explore the preference-inducing properties of oxytocin by examining its effects on object preference on ovariectomized female rats. In other words, we assessed whether these effects would apply to objects and if they would be persistent across species. Eight rats were infused with oxytocin into the left ventricle and object preference was assessed at two delays: 30min and 4h. At the 30min delay, oxytocin-treated animals showed preference for the familiar object, whereas saline-treated controls exhibited preference for the novel object. At the 4h delay, both groups showed novel-object preference. Our findings show that oxytocin modulates object preference in the female rat at a shorter delay, similar to the findings from partner-preference studies in the prairie vole, suggesting that the mechanisms driving object preference might be in part similar to those responsible for partner preference. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Galaxy growth in a massive halo in the first billion years of cosmic history

    Science.gov (United States)

    Marrone, D. P.; Spilker, J. S.; Hayward, C. C.; Vieira, J. D.; Aravena, M.; Ashby, M. L. N.; Bayliss, M. B.; Béthermin, M.; Brodwin, M.; Bothwell, M. S.; Carlstrom, J. E.; Chapman, S. C.; Chen, Chian-Chou; Crawford, T. M.; Cunningham, D. J. M.; De Breuck, C.; Fassnacht, C. D.; Gonzalez, A. H.; Greve, T. R.; Hezaveh, Y. D.; Lacaille, K.; Litke, K. C.; Lower, S.; Ma, J.; Malkan, M.; Miller, T. B.; Morningstar, W. R.; Murphy, E. J.; Narayanan, D.; Phadke, K. A.; Rotermund, K. M.; Sreevani, J.; Stalder, B.; Stark, A. A.; Strandet, M. L.; Tang, M.; Weiß, A.

    2018-01-01

    According to the current understanding of cosmic structure formation, the precursors of the most massive structures in the Universe began to form shortly after the Big Bang, in regions corresponding to the largest fluctuations in the cosmic density field. Observing these structures during their period of active growth and assembly—the first few hundred million years of the Universe—is challenging because it requires surveys that are sensitive enough to detect the distant galaxies that act as signposts for these structures and wide enough to capture the rarest objects. As a result, very few such objects have been detected so far. Here we report observations of a far-infrared-luminous object at redshift 6.900 (less than 800 million years after the Big Bang) that was discovered in a wide-field survey. High-resolution imaging shows it to be a pair of extremely massive star-forming galaxies. The larger is forming stars at a rate of 2,900 solar masses per year, contains 270 billion solar masses of gas and 2.5 billion solar masses of dust, and is more massive than any other known object at a redshift of more than 6. Its rapid star formation is probably triggered by its companion galaxy at a projected separation of 8 kiloparsecs. This merging companion hosts 35 billion solar masses of stars and has a star-formation rate of 540 solar masses per year, but has an order of magnitude less gas and dust than its neighbour and physical conditions akin to those observed in lower-metallicity galaxies in the nearby Universe. These objects suggest the presence of a dark-matter halo with a mass of more than 100 billion solar masses, making it among the rarest dark-matter haloes that should exist in the Universe at this epoch.

  12. The distribution of satellites around massive galaxies at 1 < z < 3 in ZFOURGE/CANDELS: Dependence on star formation activity

    Energy Technology Data Exchange (ETDEWEB)

    Kawinwanichakij, Lalitwadee; Papovich, Casey; Quadri, Ryan F.; Tran, Kim-Vy H.; Mehrtens, Nicola [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Spitler, Lee R.; Cowley, Michael [Department of Physics and Astronomy, Faculty of Sciences, Macquarie University, Sydney, NSW 2109 (Australia); Kacprzak, Glenn G.; Glazebrook, Karl; Nanayakkara, Themiya [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Labbé, Ivo; Straatman, Caroline M. S. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Allen, Rebecca [Australian Astronomical Observatories, P.O. Box 915, North Ryde, NSW 1670 (Australia); Davé, Romeel [University of the Western Cape, Bellville, Cape Town 7535 (South Africa); Dekel, Avishai [Center for Astrophysics and Planetary Science, Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Ferguson, Henry C.; Koekemoer, Anton M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Hartley, W. G. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Koo, David C. [University of California Observatories/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Lu, Yu, E-mail: kawinwanichakij@physics.tamu.edu [Kavli Institute for Particle Astrophysics and Cosmology, 452 Lomita Mall, Stanford, CA 94305 (United States); and others

    2014-09-10

    We study the statistical distribution of satellites around star-forming and quiescent central galaxies at 1 < z < 3 using imaging from the FourStar Galaxy Evolution Survey and the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey. The deep near-IR data select satellites down to log (M/M {sub ☉}) > 9 at z < 3. The radial satellite distribution around centrals is consistent with a projected Navarro-Frenk-White profile. Massive quiescent centrals, log (M/M {sub ☉}) > 10.78, have ∼2 times the number of satellites compared to star-forming centrals with a significance of 2.7σ even after accounting for differences in the centrals' stellar-mass distributions. We find no statistical difference in the satellite distributions of intermediate-mass quiescent and star-forming centrals, 10.48 < log (M/M {sub ☉}) < 10.78. Compared to the Guo et al. semi-analytic model, the excess number of satellites indicates that quiescent centrals have halo masses 0.3 dex larger than star-forming centrals, even when the stellar-mass distributions are fixed. We use a simple toy model that relates halo mass and quenching, which roughly reproduces the observed quenched fractions and the differences in halo mass between star-forming and quenched galaxies only if galaxies have a quenching probability that increases with halo mass from ∼0 for log (M{sub h} /M {sub ☉}) ∼ 11 to ∼1 for log (M{sub h} /M {sub ☉}) ∼ 13.5. A single halo-mass quenching threshold is unable to reproduce the quiescent fraction and satellite distribution of centrals. Therefore, while halo quenching may be an important mechanism, it is unlikely to be the only factor driving quenching. It remains unclear why a high fraction of centrals remain star-forming even in relatively massive halos.

  13. Curtain-Lifting Winds Allow Rare Glimpse into Massive Star Factory

    Science.gov (United States)

    2003-06-01

    of the Swedish-ESO Submillimeter Telescpe (SEST) at the La Silla Observatory. Large-scale mapping of the distribution of the CS-molecule showed the structure and motions of the dense gas in the giant molecular cloud, from which the young stars in NGC 3603 originate. A total of 13 molecular clumps were detected and their sizes, masses and densities were determined. These observations also showed that the intense radiation and strong stellar winds from the hot stars in the central cluster have "carved a cavity" in the molecular cloud; this comparatively empty and transparent region now measures about 8 light-years across. Mid-infrared imaging (at wavelengths 11.9 and 18 µm) was made of selected regions in NGC 3603 with the TIMMI 2 instrument mounted on the ESO 3.6-m telescope. This constitutes the first sub-arcsec resolution mid-IR survey of NGC 3603 and serves in particular to show the warm dust distribution in the region. The survey gives a clear indication of intense, on-going star formation processes. Many different types of objects were detected, including extremely hot Wolf-Rayet stars and protostars; altogether 36 mid-IR point sources and 42 knots of diffuse emission were identified. In the area surveyed, the protostar IRS 9A is found to be the most luminous point source at both wavelengths; two other sources, designated IRS 9B and IRS 9C in the immediate vicinity are also very bright on the TIMMI 2 images, providing further indication that this is the site of an association of protostars in its own right. The collection of high-quality images of the IRS 9 area shown in PR Photo 16b/03 is well suited to investigate the nature and the evolutionary status of the highly obscured objects located there, IRS 9A-C. They are situated on the side of the massive molecular cloud core NGC 3603 MM 2 that faces the central cluster of young stars (PR Photo 16a/03) and were apparently only recently "liberated" from most of their natal gas and dust environment by strong stellar

  14. On maximal massive 3D supergravity

    OpenAIRE

    Bergshoeff , Eric A; Hohm , Olaf; Rosseel , Jan; Townsend , Paul K

    2010-01-01

    ABSTRACT We construct, at the linearized level, the three-dimensional (3D) N = 4 supersymmetric " general massive supergravity " and the maximally supersymmetric N = 8 " new massive supergravity ". We also construct the maximally supersymmetric linearized N = 7 topologically massive supergravity, although we expect N = 6 to be maximal at the non-linear level. (Bergshoeff, Eric A) (Hohm, Olaf) (Rosseel, Jan) P.K.Townsend@da...

  15. EVOLUTION OF MASSIVE PROTOSTARS VIA DISK ACCRETION

    International Nuclear Information System (INIS)

    Hosokawa, Takashi; Omukai, Kazuyuki; Yorke, Harold W.

    2010-01-01

    Mass accretion onto (proto-)stars at high accretion rates M-dot * > 10 -4 M sun yr -1 is expected in massive star formation. We study the evolution of massive protostars at such high rates by numerically solving the stellar structure equations. In this paper, we examine the evolution via disk accretion. We consider a limiting case of 'cold' disk accretion, whereby most of the stellar photosphere can radiate freely with negligible backwarming from the accretion flow, and the accreting material settles onto the star with the same specific entropy as the photosphere. We compare our results to the calculated evolution via spherically symmetric accretion, the opposite limit, whereby the material accreting onto the star contains the entropy produced in the accretion shock front. We examine how different accretion geometries affect the evolution of massive protostars. For cold disk accretion at 10 -3 M sun yr -1 , the radius of a protostar is initially small, R * ≅ a few R sun . After several solar masses have accreted, the protostar begins to bloat up and for M * ≅ 10 M sun the stellar radius attains its maximum of 30-400 R sun . The large radius ∼100 R sun is also a feature of spherically symmetric accretion at the same accreted mass and accretion rate. Hence, expansion to a large radius is a robust feature of accreting massive protostars. At later times, the protostar eventually begins to contract and reaches the zero-age main sequence (ZAMS) for M * ≅ 30 M sun , independent of the accretion geometry. For accretion rates exceeding several 10 -3 M sun yr -1 , the protostar never contracts to the ZAMS. The very large radius of several hundreds R sun results in the low effective temperature and low UV luminosity of the protostar. Such bloated protostars could well explain the existence of bright high-mass protostellar objects, which lack detectable H II regions.

  16. Monitoring mixed venous oxygen saturation in patients with obstructive shock after massive pulmonary embolism.

    Science.gov (United States)

    Krivec, Bojan; Voga, Gorazd; Podbregar, Matej

    2004-05-31

    Patients with massive pulmonary embolism and obstructive shock usually require hemodynamic stabilization and thrombolysis. Little is known about the optimal and proper use of volume infusion and vasoactive drugs, or about the titration of thrombolytic agents in patients with relative contraindication for such treatment. The aim of the study was to find the most rapidly changing hemodynamic variable to monitor and optimize the treatment of patients with obstructive shock following massive pulmonary embolism. Ten consecutive patients hospitalized in the medical intensive care unit in the community General Hospital with obstructive shock following massive pulmonary embolism were included in the prospective observational study. Heart rate, systolic arterial pressure, central venous pressure, mean pulmonary-artery pressure, cardiac index, total pulmonary vascular-resistance index, mixed venous oxygen saturation, and urine output were measured on admission and at 1, 2, 3, 4, 8, 12, and 16 hours. Patients were treated with urokinase through the distal port of a pulmonary-artery catheter. At 1 hour, mixed venous oxygen saturation, systolic arterial pressure and cardiac index were higher than their admission values (31+/-10 vs. 49+/-12%, p<0.0001; 86+/-12 vs. 105+/-17 mmHg, p<0.01; 1.5+/-0.4 vs. 1.9+/-0.7 L/min/m2, p<0.05; respectively), whereas heart rate, central venous pressure, mean pulmonary-artery pressure and urine output remained unchanged. Total pulmonary vascular-resistance index was lower than at admission (29+/-10 vs. 21+/-12 mmHg/L/min/m2, p<0.05). The relative change of mixed venous oxygen saturation at hour 1 was higher than the relative changes of all other studied variables (p<0.05). Serum lactate on admission and at 12 hours correlated to mixed venous oxygen saturation (r=-0.855, p<0.001). In obstructive shock after massive pulmonary embolism, mixed venous oxygen saturation changes more rapidly than other standard hemodynamic variables.

  17. GRay: A MASSIVELY PARALLEL GPU-BASED CODE FOR RAY TRACING IN RELATIVISTIC SPACETIMES

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Chi-kwan; Psaltis, Dimitrios; Özel, Feryal [Department of Astronomy, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States)

    2013-11-01

    We introduce GRay, a massively parallel integrator designed to trace the trajectories of billions of photons in a curved spacetime. This graphics-processing-unit (GPU)-based integrator employs the stream processing paradigm, is implemented in CUDA C/C++, and runs on nVidia graphics cards. The peak performance of GRay using single-precision floating-point arithmetic on a single GPU exceeds 300 GFLOP (or 1 ns per photon per time step). For a realistic problem, where the peak performance cannot be reached, GRay is two orders of magnitude faster than existing central-processing-unit-based ray-tracing codes. This performance enhancement allows more effective searches of large parameter spaces when comparing theoretical predictions of images, spectra, and light curves from the vicinities of compact objects to observations. GRay can also perform on-the-fly ray tracing within general relativistic magnetohydrodynamic algorithms that simulate accretion flows around compact objects. Making use of this algorithm, we calculate the properties of the shadows of Kerr black holes and the photon rings that surround them. We also provide accurate fitting formulae of their dependencies on black hole spin and observer inclination, which can be used to interpret upcoming observations of the black holes at the center of the Milky Way, as well as M87, with the Event Horizon Telescope.

  18. ON THE SIMULTANEOUS EVOLUTION OF MASSIVE PROTOSTARS AND THEIR HOST CORES

    International Nuclear Information System (INIS)

    Kuiper, R.; Yorke, H. W.

    2013-01-01

    Studies of the evolution of massive protostars and the evolution of their host molecular cloud cores are commonly treated as separate problems. However, interdependencies between the two can be significant. Here, we study the simultaneous evolution of massive protostars and their host molecular cores using a multi-dimensional radiation hydrodynamics code that incorporates the effects of the thermal pressure and radiative acceleration feedback of the centrally forming protostar. The evolution of the massive protostar is computed simultaneously using the stellar evolution code STELLAR, modified to include the effects of variable accretion. The interdependencies are studied in three different collapse scenarios. For comparison, stellar evolutionary tracks at constant accretion rates and the evolution of the host cores using pre-computed stellar evolutionary tracks are computed. The resulting interdependencies of the protostellar evolution and the evolution of the environment are extremely diverse and depend on the order of events, in particular the time of circumstellar accretion disk formation with respect to the onset of the bloating phase of the star. Feedback mechanisms affect the instantaneous accretion rate and the protostar's radius, temperature, and luminosity on timescales t ≤ 5 kyr, corresponding to the accretion timescale and Kelvin-Helmholtz contraction timescale, respectively. Nevertheless, it is possible to approximate the overall protostellar evolution in many cases by pre-computed stellar evolutionary tracks assuming appropriate constant average accretion rates

  19. Massive neutrinos in astrophysics

    International Nuclear Information System (INIS)

    Qadir, A.

    1982-08-01

    Massive neutrinos are among the big hopes of cosmologists. If they happen to have the right mass they can close the Universe, explain the motion of galaxies in clusters, provide galactic halos and even, possibly, explain galaxy formation. Tremaine and Gunn have argued that massive neutrinos cannot do all these things. I will explain, here, what some of us believe is wrong with their arguments. (author)

  20. The cosmic evolution of massive black holes in the Horizon-AGN simulation

    Science.gov (United States)

    Volonteri, M.; Dubois, Y.; Pichon, C.; Devriendt, J.

    2016-08-01

    We analyse the demographics of black holes (BHs) in the large-volume cosmological hydrodynamical simulation Horizon-AGN. This simulation statistically models how much gas is accreted on to BHs, traces the energy deposited into their environment and, consequently, the back-reaction of the ambient medium on BH growth. The synthetic BHs reproduce a variety of observational constraints such as the redshift evolution of the BH mass density and the mass function. Strong self-regulation via AGN feedback, weak supernova feedback, and unresolved internal processes result in a tight BH-galaxy mass correlation. Starting at z ˜ 2, tidal stripping creates a small population of BHs over-massive with respect to the halo. The fraction of galaxies hosting a central BH or an AGN increases with stellar mass. The AGN fraction agrees better with multi-wavelength studies, than single-wavelength ones, unless obscuration is taken into account. The most massive haloes present BH multiplicity, with additional BHs gained by ongoing or past mergers. In some cases, both a central and an off-centre AGN shine concurrently, producing a dual AGN. This dual AGN population dwindles with decreasing redshift, as found in observations. Specific accretion rate and Eddington ratio distributions are in good agreement with observational estimates. The BH population is dominated in turn by fast, slow, and very slow accretors, with transitions occurring at z = 3 and z = 2, respectively.

  1. Bronchial artery embolization by using permanent particles for the treatment of massive hemoptysis

    International Nuclear Information System (INIS)

    Zu Qingquan; Shi Haibin; Yang Zhengqiang; Liu Sheng; Zhou Chungao; Xia Jinguo; Zhao Linbo; Li Linsun

    2011-01-01

    Objective: Massive hemoptysis is always a life-threatening respiratory disease and requires emergency management. This study is to evaluate the clinical efficacy and safety of bronchial artery embolization (BAE) by using permanent particles in the management of massive hemoptysis. Methods: Thirty-three patients with massive hemoptysis who had failed to respond to medical management received BAE. The causative diseases included bronchiectasis (n = 24), bronchogenic carcinoma (n = 4), bronchiectasis complicated with tuberculosis (n = 2), bronchial disease (n = 2) and traumatic destroyed lung (n = 1). Embolization with sodium alginate microspheres (KMG) was performed in all patients, and additional use of microcoils was carried out in patients complicated with bronchial-pulmonary fistulae. All patients were followed up for at least 3 months. Results: BAE was successfully accomplished in all patients. The cessation of hemoptysis was immediately obtained in all patients, with a success rate of 100%. Recurrence of hemoptysis within one month after BAE was seen in 3 patients (9.1%, 3/33). No serious complications occurred and the mean postoperative hospitalization days of the patients were 10 days. Conclusion: With satisfactory instant clinical results, BAE by using permanent particles is a safe, effective treatment for the massive hemoptysis. (authors)

  2. X-RAY EMISSION FROM MAGNETIC MASSIVE STARS

    International Nuclear Information System (INIS)

    Nazé, Yaël; Petit, Véronique; Rinbrand, Melanie; Owocki, Stan; Cohen, David; Ud-Doula, Asif; Wade, Gregg A.

    2014-01-01

    Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering ∼60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower- M-dot B stars and flattens for the more luminous, higher- M-dot O stars. As the winds are radiatively driven, these scalings can be equivalently written as relations with the bolometric luminosity. The observed X-ray luminosities, and their trend with mass-loss rates, are well reproduced by new MHD models, although a few overluminous stars (mostly rapidly rotating objects) exist. No relation is found between other X-ray properties (plasma temperature, absorption) and stellar or magnetic parameters, contrary to expectations (e.g., higher temperature for stronger mass-loss rate). This suggests that the main driver for the plasma properties is different from the main determinant of the X-ray luminosity. Finally, variations of the X-ray hardnesses and luminosities, in phase with the stellar rotation period, are detected for some objects and they suggest that some temperature stratification exists in massive stars' magnetospheres

  3. Gauge invariant Lagrangian formulation of massive higher spin fields in (A)dS3 space

    International Nuclear Information System (INIS)

    Buchbinder, I.L.; Snegirev, T.V.; Zinoviev, Yu.M.

    2012-01-01

    We develop the frame-like formulation of massive bosonic higher spin fields in the case of three-dimensional (A)dS space with the arbitrary cosmological constant. The formulation is based on gauge invariant description by involving the Stueckelberg auxiliary fields. The explicit form of the Lagrangians and the gauge transformation laws are found. The theory can be written in terms of gauge invariant objects similar to the massless theories, thus allowing us to hope to use the same methods for investigation of interactions. In the massive spin 3 field example we are able to rewrite the Lagrangian using the new the so-called separated variables, so that the study of Lagrangian formulation reduces to finding the Lagrangian containing only half of the fields. The same construction takes places for arbitrary integer spin field as well. Further working in terms of separated variables, we build Lagrangian for arbitrary integer spin and write it in terms of gauge invariant objects. Also, we demonstrate how to restore the full set of variables, thus receiving Lagrangian for the massive fields of arbitrary spin in the terms of initial fields.

  4. Economic opportunities and challenges posed by China for Mexico and Central America

    OpenAIRE

    Dussel Peters, Enrique

    2005-01-01

    "This study offers a basis for understanding China's performance from a Latin American perspective, and stressing the massive economic opportunities and challenges, and particularly for Central America and Mexico. Moreover, the document assesses in detail the macroeconomic, trade and employment policy and institutional changes in China and its potential effects in Central America and Mexico. These effects are analyzed in the Chinese, Central American, Mexican and US market in general, but als...

  5. Astrophysics of Super-Massive Black Hole Mergers

    Science.gov (United States)

    Schnittman, Jeremy D.

    2013-01-01

    We present here an overview of recent work in the subject of astrophysical manifestations of super-massive black hole (SMBH) mergers. This is a field that has been traditionally driven by theoretical work, but in recent years has also generated a great deal of interest and excitement in the observational astronomy community. In particular, the electromagnetic (EM) counterparts to SMBH mergers provide the means to detect and characterize these highly energetic events at cosmological distances, even in the absence of a space-based gravitational-wave observatory. In addition to providing a mechanism for observing SMBH mergers, EM counterparts also give important information about the environments in which these remarkable events take place, thus teaching us about the mechanisms through which galaxies form and evolve symbiotically with their central black holes.

  6. Massive intracranial calcifications in a patient with systemic lupus erythematosus

    International Nuclear Information System (INIS)

    Gasparetto, Emerson L.; Carvalho Neto, Arnolfo de; Ono, Sergio E.

    2004-01-01

    Central nervous system involvement is frequently reported in patients with systemic lupus erythematosus. Computed tomography and magnetic resonance imaging studies usually show brain atrophy, cerebral infarction and/or intracranial bleeding. Extensive intracranial calcification in patients with systemic lupus erythematosus is rare. We report a case of a patient with systemic lupus erythematosus who presented with seizures and massive basal ganglia calcification and mild calcifications in the frontal lobes, seen on the brain computed tomography scan. Magnetic resonance imaging showed hyperintensity on FLAIR images and hypointense signals on T2 * gradient echo images in the basal ganglia. (author)

  7. MASSIVE INFANT STARS ROCK THEIR CRADLE

    Science.gov (United States)

    2002-01-01

    that are responsible for lighting up this cloud of gas. The apparently innocuous-looking star at the very center of the nebula, just below the brightest region, is actually about 30 times more massive and almost 200,000 times brighter than our Sun. The intense light and powerful stellar 'winds' from this ultra-bright star have cleared away the surrounding gas to form a large cavity. The bubble is approximately 25 light-years in diameter - about the same size as the famous star-forming Orion Nebula. The Orion Nebula is sculpted by intense radiation from newly born stars in the same way as N83B. Astronomers estimate that the spherical void in N83B must have been carved out of the nebula very recently - in astronomical terms - maybe as little as 30,000 years ago. The hottest star in N83B is 45 times more massive than the Sun and is embedded in the brightest region in the nebula. This bright region, situated just above the center, is only about 2 light-years across. The region's small size and its intense glow are telltale signs of a very young, massive star. This star is the youngest newcomer to this part of the Large Magellanic Cloud. The Hubble image shows a bright arc structure just below the luminous star. This impressive ridge may have been created in the glowing gas by the hot star's powerful wind. Measurements of the age of this star and neighboring stars in the nebula show that they are younger than the nebula's central star. Their formation may have been 'triggered' by the violent wind from the central star. This 'chain-reaction' of stellar births seems to be common in the Universe. About 20 young and luminous stars have been identified in the region, but it may well be that many more massive stars remain undetected in other areas of the Large Magellanic Cloud, hidden by dust in small clusters like N83B. To the right of the glowing N83B is a much larger diffuse nebula, known as DEM22d, which is partly obscured by an extended lane of dust and gas. This image is

  8. Dominant object detection for autonomous vision-based surveillance

    NARCIS (Netherlands)

    Celik, H.

    2010-01-01

    The deployment of visual surveillance and monitoring systems has reached massive proportions. Consequently, a need to automate the processes involved in retrieving useful information from surveillance videos, such as detecting and counting objects, and interpreting their individual and joint

  9. Photometric Selection of a Massive Galaxy Catalog with z ≥ 0.55

    Science.gov (United States)

    Núñez, Carolina; Spergel, David N.; Ho, Shirley

    2017-02-01

    We present the development of a photometrically selected massive galaxy catalog, targeting Luminous Red Galaxies (LRGs) and massive blue galaxies at redshifts of z≥slant 0.55. Massive galaxy candidates are selected using infrared/optical color-color cuts, with optical data from the Sloan Digital Sky Survey (SDSS) and infrared data from “unWISE” forced photometry derived from the Wide-field Infrared Survey Explorer (WISE). The selection method is based on previously developed techniques to select LRGs with z> 0.5, and is optimized using receiver operating characteristic curves. The catalog contains 16,191,145 objects, selected over the full SDSS DR10 footprint. The redshift distribution of the resulting catalog is estimated using spectroscopic redshifts from the DEEP2 Galaxy Redshift Survey and photometric redshifts from COSMOS. Restframe U - B colors from DEEP2 are used to estimate LRG selection efficiency. Using DEEP2, the resulting catalog has an average redshift of z = 0.65, with a standard deviation of σ =2.0, and an average restframe of U-B=1.0, with a standard deviation of σ =0.27. Using COSMOS, the resulting catalog has an average redshift of z = 0.60, with a standard deviation of σ =1.8. We estimate 34 % of the catalog to be blue galaxies with z≥slant 0.55. An estimated 9.6 % of selected objects are blue sources with redshift z0.55. Stellar contamination is estimated to be 1.8%.

  10. A RING/DISK/OUTFLOW SYSTEM ASSOCIATED WITH W51 NORTH: A VERY MASSIVE STAR IN THE MAKING

    International Nuclear Information System (INIS)

    Zapata, Luis A.; Schilke, Peter; Menten, Karl; Ho, Paul T. P.; Rodriguez, Luis F.; Palau, Aina; Garrod, Robin T.

    2009-01-01

    Sensitive and high angular resolution (∼0.''4) SO 2 [22 2,20 → 22 1,21 ] and SiO[5 → 4] line and 1.3 and 7 mm continuum observations made with the Submillimeter Array (SMA) and the Very Large Array (VLA) toward the young massive cluster W51 IRS2 are presented. We report the presence of a large (of about 3000 AU) and massive (40 M sun ) dusty circumstellar disk and a hot gas molecular ring around a high-mass protostar or a compact small stellar system associated with W51 North. The simultaneous observations of the silicon monoxide molecule, an outflow gas tracer, further revealed a massive (200 M sun ) and collimated (∼14 0 ) outflow nearly perpendicular to the dusty and molecular structures suggesting thus the presence of a single very massive protostar with a bolometric luminosity on the order of 10 5 L sun . A molecular hybrid local thermodynamic equilibrium model of a Keplerian and infalling disk with an inner cavity and a central stellar mass of more than 60 M sun agrees well with the SO 2 [22 2,20 → 22 1,21 ] line observations. Finally, these results suggest that mechanisms, such as mergers of low- and intermediate-mass stars, might not be necessary for forming very massive stars.

  11. Spitzer view of massive star formation in the tidally stripped Magellanic Bridge

    International Nuclear Information System (INIS)

    Chen, C.-H. Rosie; Indebetouw, Remy; Muller, Erik; Kawamura, Akiko; Gordon, Karl D.; Meixner, Margaret; Seale, Jonathan P.; Shiao, Bernie; Sewiło, Marta; Whitney, Barbara A.; Meade, Marilyn R.; Fukui, Yasuo; Madden, Suzanne C.; Oliveira, Joana M.; Van Loon, Jacco Th.; Robitaille, Thomas P.

    2014-01-01

    The Magellanic Bridge is the nearest low-metallicity, tidally stripped environment, offering a unique high-resolution view of physical conditions in merging and forming galaxies. In this paper, we present an analysis of candidate massive young stellar objects (YSOs), i.e., in situ, current massive star formation (MSF) in the Bridge using Spitzer mid-IR and complementary optical and near-IR photometry. While we definitely find YSOs in the Bridge, the most massive are ∼10 M ☉ , <<45 M ☉ found in the LMC. The intensity of MSF in the Bridge also appears to be decreasing, as the most massive YSOs are less massive than those formed in the past. To investigate environmental effects on MSF, we have compared properties of massive YSOs in the Bridge to those in the LMC. First, YSOs in the Bridge are apparently less embedded than in the LMC: 81% of Bridge YSOs show optical counterparts, compared to only 56% of LMC sources with the same range of mass, circumstellar dust mass, and line-of-sight extinction. Circumstellar envelopes are evidently more porous or clumpy in the Bridge's low-metallicity environment. Second, we have used whole samples of YSOs in the LMC and the Bridge to estimate the probability of finding YSOs at a given H I column density, N(H I). We found that the LMC has ∼3 × higher probability than the Bridge for N(H I) >12 × 10 20 cm –2 , but the trend reverses at lower N(H I). Investigating whether this lower efficiency relative to H I is due to less efficient molecular cloud formation or to less efficient cloud collapse, or to both, will require sensitive molecular gas observations.

  12. Spitzer view of massive star formation in the tidally stripped Magellanic Bridge

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.-H. Rosie; Indebetouw, Remy [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Muller, Erik; Kawamura, Akiko [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Gordon, Karl D.; Meixner, Margaret; Seale, Jonathan P.; Shiao, Bernie [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Sewiło, Marta [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Whitney, Barbara A.; Meade, Marilyn R. [Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States); Fukui, Yasuo [Department of Astrophysics, Nagoya University, Furocho, Chikusaku, Nagoya 464-8602 (Japan); Madden, Suzanne C. [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Oliveira, Joana M.; Van Loon, Jacco Th. [Astrophysics Group, Lennard-Jones Laboratories, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Robitaille, Thomas P., E-mail: rchen@mpifr-bonn.mpg.de [Max Planck Institute for Astronomy, D-69117 Heidelberg (Germany)

    2014-04-20

    The Magellanic Bridge is the nearest low-metallicity, tidally stripped environment, offering a unique high-resolution view of physical conditions in merging and forming galaxies. In this paper, we present an analysis of candidate massive young stellar objects (YSOs), i.e., in situ, current massive star formation (MSF) in the Bridge using Spitzer mid-IR and complementary optical and near-IR photometry. While we definitely find YSOs in the Bridge, the most massive are ∼10 M {sub ☉}, <<45 M {sub ☉} found in the LMC. The intensity of MSF in the Bridge also appears to be decreasing, as the most massive YSOs are less massive than those formed in the past. To investigate environmental effects on MSF, we have compared properties of massive YSOs in the Bridge to those in the LMC. First, YSOs in the Bridge are apparently less embedded than in the LMC: 81% of Bridge YSOs show optical counterparts, compared to only 56% of LMC sources with the same range of mass, circumstellar dust mass, and line-of-sight extinction. Circumstellar envelopes are evidently more porous or clumpy in the Bridge's low-metallicity environment. Second, we have used whole samples of YSOs in the LMC and the Bridge to estimate the probability of finding YSOs at a given H I column density, N(H I). We found that the LMC has ∼3 × higher probability than the Bridge for N(H I) >12 × 10{sup 20} cm{sup –2}, but the trend reverses at lower N(H I). Investigating whether this lower efficiency relative to H I is due to less efficient molecular cloud formation or to less efficient cloud collapse, or to both, will require sensitive molecular gas observations.

  13. Massive Born--Infeld and Other Dual Pairs

    CERN Document Server

    Ferrara, S

    2015-01-01

    We consider massive dual pairs of p-forms and (D-p-1)-forms described by non-linear Lagrangians, where non-linear curvature terms in one theory translate into non-linear mass-like terms in the dual theory. In particular, for D=2p and p even the two non-linear structures coincide when the non-linear massless theory is self-dual. This state of affairs finds a natural realization in the four-dimensional massive N=1 supersymmetric Born-Infeld action, which describes either a massive vector multiplet or a massive linear (tensor) multiplet with a Born-Infeld mass-like term. These systems should play a role for the massive gravitino multiplet obtained from a partial super-Higgs in N=2 Supergravity.

  14. MASSIVE+: The Growth Histories of MASSIVE Survey Galaxies from their Globular Cluster Colors

    Science.gov (United States)

    Blakeslee, John

    2017-08-01

    The MASSIVE survey is targeting the 100 most massive galaxies within 108 Mpc that are visible in the northern sky. These most massive galaxies in the present-day universe reside in a surprisingly wide variety of environments, from rich clusters to fossil groups to near isolation. We propose to use WFC3/UVIS and ACS to carry out a deep imaging study of the globular cluster populations around a selected subset of the MASSIVE targets. Though much is known about GC systems of bright galaxies in rich clusters, we know surprisingly little about the effects of environment on these systems. The MASSIVE sample provides a golden opportunity to learn about the systematics of GC systems and what they can tell us about environmental drivers on the evolution of the highest mass galaxies. The most pressing questions to be addressed include: (1) Do isolated giants have the same constant mass fraction of GCs to total halo mass as BCGs of similar luminosity? (2) Do their GC systems show the same color (metallicity) distribution, which is an outcome of the mass spectrum of gas-rich halos during hierarchical growth? (3) Do the GCs in isolated high-mass galaxies follow the same radial distribution versus metallicity as in rich environments (a test of the relative importance of growth by accretion)? (4) Do the GCs of galaxies in sparse environments follow the same mass function? Our proposed second-band imaging will enable us to secure answers to these questions and add enormously to the legacy value of existing HST imaging of the highest mass galaxies in the universe.

  15. Massive Sensor Array Fault Tolerance: Tolerance Mechanism and Fault Injection for Validation

    Directory of Open Access Journals (Sweden)

    Dugan Um

    2010-01-01

    Full Text Available As today's machines become increasingly complex in order to handle intricate tasks, the number of sensors must increase for intelligent operations. Given the large number of sensors, detecting, isolating, and then tolerating faulty sensors is especially important. In this paper, we propose fault tolerance architecture suitable for a massive sensor array often found in highly advanced systems such as autonomous robots. One example is the sensitive skin, a type of massive sensor array. The objective of the sensitive skin is autonomous guidance of machines in unknown environments, requiring elongated operations in a remote site. The entirety of such a system needs to be able to work remotely without human attendance for an extended period of time. To that end, we propose a fault-tolerant architecture whereby component and analytical redundancies are integrated cohesively for effective failure tolerance of a massive array type sensor or sensor system. In addition, we discuss the evaluation results of the proposed tolerance scheme by means of fault injection and validation analysis as a measure of system reliability and performance.

  16. NGC 346: Looking in the Cradle of a Massive Star Cluster

    Science.gov (United States)

    Gouliermis, Dimitrios A.; Hony, Sacha

    2017-03-01

    two parameters with a considerable scatter. The fraction of stellar over the total (gas plus young stars) mass is found to be systematically higher within the central 15 pc (where the young massive cluster is located) than outside, which suggests variations in the star formation efficiency within the same star-forming complex. This trend possibly reflects a change of star formation efficiency in N66 between clustered and non-clustered star formation. Our findings suggest that the formation of NGC 346 is the combined result of star formation regulated by turbulence and of early dynamical evolution induced by the gravitational potential of the dense interstellar medium.

  17. Diagnosis and treatment of shock due to massive pulmonary embolism: approach with transesophageal echocardiography and intrapulmonary thrombolysis.

    Science.gov (United States)

    Krivec, B; Voga, G; Zuran, I; Skale, R; Pareznik, R; Podbregar, M; Noc, M

    1997-11-05

    To evaluate the diagnostic value of transesophageal echocardiography (TEE) as an initial diagnostic tool in shocked patients. The second objective was to study therapeutic impact of intrapulmonary thrombolysis in patients with diagnosed massive pulmonary embolism. Prospective observational study. Medical ICU in 800-bed general hospital. Twenty-four consecutive patients with unexplained shock and distended jugular veins. In 18 patients, right ventricular dilatation with global or segmental hypokinesis was documented. In addition, central pulmonary thromboemboli (12 patients), reduced contrast flow in right pulmonary artery (one patient), and right ventricular free wall akinesis (one patient) were found. No additional echocardiographic findings were apparent in four patients. According to pulmonary scintigraphy or autopsy, sensitivity of TEE for diagnosis of massive pulmonary embolism (MPE) in patients with right ventricular dilatation was 92% and specificity was 100%. In patients without right ventricular dilatation, left ventricular dysfunction (four patients) or cardiac tamponade (two patients) was confirmed. Intrapulmonary thrombolysis was evaluated in 11 of 13 patients with MPE. Two patients died prior to attempted thrombolysis. Three patients received streptokinase and eight received urokinase. Twenty-four hours after beginning of treatment, total pulmonary resistance index significantly decreased for 59% and mean pulmonary artery pressure for 31%. Cardiac index increased for 74%. Nine of 11 patients receiving thrombolysis survived to hospital discharge. Bedside TEE is a valuable tool for diagnosis of MPE. It enables immediate intrapulmonary thrombolysis, which seems to be an effective therapeutic alternative in our group of patients with obstructive shock.

  18. The central uplift of Ritchey crater, Mars

    Science.gov (United States)

    Ding, Ning; Bray, Veronica J.; McEwen, Alfred S.; Mattson, Sarah S.; Okubo, Chris H.; Chojnacki, Matthew; Tornabene, Livio L.

    2015-01-01

    Ritchey crater is a ∼79 km diameter complex crater near the boundary between Hesperian ridged plains and Noachian highland terrain on Mars (28.8°S, 309.0°E) that formed after the Noachian. High Resolution Imaging Science Experiment (HiRISE) images of the central peak reveal fractured massive bedrock and megabreccia with large clasts. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral analysis reveals low calcium pyroxene (LCP), olivine (OL), hydrated silicates (phyllosilicates) and a possible identification of plagioclase bedrock. We mapped the Ritchey crater central uplift into ten units, with 4 main groups from oldest and originally deepest to youngest: (1) megabreccia with large clasts rich in LCP and OL, and with alteration to phyllosilicates; (2) massive bedrock with bright and dark regions rich in LCP or OL, respectively; (3) LCP and OL-rich impactites draped over the central uplift; and (4) aeolian deposits. We interpret the primitive martian crust as igneous rocks rich in LCP, OL, and probably plagioclase, as previously observed in eastern Valles Marineris. We do not observe high-calcium pyroxene (HCP) rich bedrock as seen in Argyre or western Valles Marineris. The association of phyllosilicates with deep megabreccia could be from impact-induced alteration, either as a result of the Richey impact, or alteration of pre-existing impactites from Argyre basin and other large impacts that preceded the Ritchey impact, or both.

  19. The central uplift of Ritchey crater, Mars

    Science.gov (United States)

    Ding, Ning; Bray, Veronica J.; McEwen, Alfred S.; Mattson, Sarah S.; Okubo, Chris H.; Chojnacki, Matthew; Tornabene, Livio L.

    2015-05-01

    Ritchey crater is a ∼79 km diameter complex crater near the boundary between Hesperian ridged plains and Noachian highland terrain on Mars (28.8°S, 309.0°E) that formed after the Noachian. High Resolution Imaging Science Experiment (HiRISE) images of the central peak reveal fractured massive bedrock and megabreccia with large clasts. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral analysis reveals low calcium pyroxene (LCP), olivine (OL), hydrated silicates (phyllosilicates) and a possible identification of plagioclase bedrock. We mapped the Ritchey crater central uplift into ten units, with 4 main groups from oldest and originally deepest to youngest: (1) megabreccia with large clasts rich in LCP and OL, and with alteration to phyllosilicates; (2) massive bedrock with bright and dark regions rich in LCP or OL, respectively; (3) LCP and OL-rich impactites draped over the central uplift; and (4) aeolian deposits. We interpret the primitive martian crust as igneous rocks rich in LCP, OL, and probably plagioclase, as previously observed in eastern Valles Marineris. We do not observe high-calcium pyroxene (HCP) rich bedrock as seen in Argyre or western Valles Marineris. The association of phyllosilicates with deep megabreccia could be from impact-induced alteration, either as a result of the Richey impact, or alteration of pre-existing impactites from Argyre basin and other large impacts that preceded the Ritchey impact, or both.

  20. A CANDIDATE PLANETARY-MASS OBJECT WITH A PHOTOEVAPORATING DISK IN ORION

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Min; Kim, Jinyoung Serena; Apai, Dániel [Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Pascucci, Ilaria [Department of Planetary Sciences, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721 (United States); Manara, Carlo Felice [Scientific Support Office, Directorate of Science, European Space Research and Technology Centre (ESA/ESTEC), Keplerlaan 1, 2201 AZ Noordwijk (Netherlands)

    2016-12-20

    In this work, we report the discovery of a candidate planetary-mass object with a photoevaporating protoplanetary disk, Proplyd 133-353, which is near the massive star θ {sup 1} Ori C at the center of the Orion Nebula Cluster (ONC). The object was known to have extended emission pointing away from θ {sup 1} Ori C, indicating ongoing external photoevaporation. Our near-infrared spectroscopic data and the location on the H–R diagram suggest that the central source of Proplyd 133-353 is substellar (∼M9.5) and has a mass probably less than 13 Jupiter mass and an age younger than 0.5 Myr. Proplyd 133-353 shows a similar ratio of X-ray luminosity to stellar luminosity to other young stars in the ONC with a similar stellar luminosity and has a similar proper motion to the mean one of confirmed ONC members. We propose that Proplyd 133-353 formed in a very low-mass dusty cloud or an evaporating gas globule near θ {sup 1} Ori C as a second generation of star formation, which can explain both its young age and the presence of its disk.

  1. Environomic multi-objective optimisation of a district heating network considering centralized and decentralized heat pumps

    International Nuclear Information System (INIS)

    Molyneaux, A.; Leyland, G.; Favrat, D.

    2010-01-01

    Concern for the environment has been steadily growing in recent years, and it is becoming more common to include environmental impact and pollution costs in the design problem along with construction, investment and operating costs. To economically respond to the global environmental problems ahead, progress must be made both on more sustainable technologies and on the design methodology, which needs to adopt a more holistic approach. Heat pumps and, in particular systems integrating heat pumps and cogeneration units, offer a significant potential for greenhouse gas reduction. This paper illustrates the application of a multi-objective and multi-modal evolutionary algorithm to facilitate the design and planning of a district heating network based on a combination of centralized and decentralized heat pumps combined with on-site cogeneration. Comparisons are made with an earlier study based on a single objective environomic optimisation of the same overall model.

  2. Wide-Field Infrared Survey Explorer Observations of the Evolution of Massive Star-Forming Regions

    Science.gov (United States)

    Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Rebull, L. M.; Padgett, D. L.; Asslef, R. J.

    2012-01-01

    We present the results of a mid-infrared survey of II outer Galaxy massive star-forming regions and 3 open clusters with data from the Wide-field Infrared Survey Explorer (WISE). Using a newly developed photometric scheme to identify young stellar objects and exclude extragalactic contamination, we have studied the distribution of young stars within each region. These data tend to support the hypothesis that latter generations may be triggered by the interaction of winds and radiation from the first burst of massive star formation with the molecular cloud material leftover from that earlier generation of stars. We dub this process the "fireworks hypothesis" since star formation by this mechanism would proceed rapidly and resemble a burst of fireworks. We have also analyzed small cutout WISE images of the structures around the edges of these massive star-forming regions. We observe large (1-3 pc size) pillar and trunk-like structures of diffuse emission nebulosity tracing excited polycyclic aromatic hydrocarbon molecules and small dust grains at the perimeter of the massive star-forming regions. These structures contain small clusters of emerging Class I and Class II sources, but some are forming only a single to a few new stars.

  3. WIDE-FIELD INFRARED SURVEY EXPLORER OBSERVATIONS OF THE EVOLUTION OF MASSIVE STAR-FORMING REGIONS

    International Nuclear Information System (INIS)

    Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Padgett, D. L.; Rebull, L. M.; Assef, R. J.

    2012-01-01

    We present the results of a mid-infrared survey of 11 outer Galaxy massive star-forming regions and 3 open clusters with data from the Wide-field Infrared Survey Explorer (WISE). Using a newly developed photometric scheme to identify young stellar objects and exclude extragalactic contamination, we have studied the distribution of young stars within each region. These data tend to support the hypothesis that latter generations may be triggered by the interaction of winds and radiation from the first burst of massive star formation with the molecular cloud material leftover from that earlier generation of stars. We dub this process the 'fireworks hypothesis' since star formation by this mechanism would proceed rapidly and resemble a burst of fireworks. We have also analyzed small cutout WISE images of the structures around the edges of these massive star-forming regions. We observe large (1-3 pc size) pillar and trunk-like structures of diffuse emission nebulosity tracing excited polycyclic aromatic hydrocarbon molecules and small dust grains at the perimeter of the massive star-forming regions. These structures contain small clusters of emerging Class I and Class II sources, but some are forming only a single to a few new stars.

  4. Thermodynamics inducing massive particles' tunneling and cosmic censorship

    International Nuclear Information System (INIS)

    Zhang, Baocheng; Cai, Qing-yu; Zhan, Ming-sheng

    2010-01-01

    By calculating the change of entropy, we prove that the first law of black hole thermodynamics leads to the tunneling probability of massive particles through the horizon, including the tunneling probability of massive charged particles from the Reissner-Nordstroem black hole and the Kerr-Newman black hole. Novelly, we find the trajectories of massive particles are close to that of massless particles near the horizon, although the trajectories of massive charged particles may be affected by electromagnetic forces. We show that Hawking radiation as massive particles tunneling does not lead to violation of the weak cosmic-censorship conjecture. (orig.)

  5. Peralkaline- and calc-alkaline-hosted volcanogenic massive sulfide deposits of the Bonnifield District, East-Central Alaska

    Science.gov (United States)

    Dusel-Bacon, Cynthia; Foley, Nora K.; Slack, John E.; Koenig, Alan E.; Oscarson, Robert L.

    2012-01-01

    Volcanogenic massive sulfide (VMS) Zn-Pb-Cu-Ag-Au deposits of the Bonnifield mining district formed during Late Devonian-Early Mississippian magmatism along the western edge of Laurentia. The largest deposits, Dry Creek and WTF, have a combined resource of 5.7 million tonnes at 10% Zn, 4% Pb, 0.3% Cu, 300 grams per tonne (g/t) Ag, and 1.6 g/t Au. These polymetallic deposits are hosted in high field strength element (HFSE)- and rare-earth element (REE)-rich peralkaline (pantelleritic) metarhyolite, and interlayered pyritic argillite and mudstone of the Mystic Creek Member of the Totatlanika Schist Formation. Mystic Creek metarhyolite and alkali basalt (Chute Creek Member) constitute a bimodal pair that formed in an extensional environment. A synvolcanic peralkaline quartz porphyry containing veins of fluorite, sphalerite, pyrite, and quartz intrudes the central footwall at Dry Creek. The Anderson Mountain deposit, located ~32 km to the southwest, occurs within calc-alkaline felsic to intermediate-composition metavolcanic rocks and associated graphitic argillite of the Wood River assemblage. Felsic metavolcanic rocks there have only slightly elevated HFSEs and REEs. The association of abundant graphitic and siliceous argillite with the felsic volcanic rocks together with low Cu contents in the Bonnifield deposits suggests classification as a siliciclastic-felsic type of VMS deposit. Bonnifield massive sulfides and host rocks were metamorphosed and deformed under greenschist-facies conditions in the Mesozoic. Primary depositional textures, generally uncommon, consist of framboids, framboidal aggregates, and spongy masses of pyrite. Sphalerite, the predominant base metal sulfide, encloses early pyrite framboids. Galena and chalcopyrite accompanied early pyrite formation but primarily formed late in the paragenetic sequence. Silver-rich tetrahedrite is a minor late phase at the Dry Creek deposit. Gold and Ag are present in low to moderate amounts in pyrite from all of

  6. The formation of massive molecular filaments and massive stars triggered by a magnetohydrodynamic shock wave

    Science.gov (United States)

    Inoue, Tsuyoshi; Hennebelle, Patrick; Fukui, Yasuo; Matsumoto, Tomoaki; Iwasaki, Kazunari; Inutsuka, Shu-ichiro

    2018-05-01

    Recent observations suggest an that intensive molecular cloud collision can trigger massive star/cluster formation. The most important physical process caused by the collision is a shock compression. In this paper, the influence of a shock wave on the evolution of a molecular cloud is studied numerically by using isothermal magnetohydrodynamics simulations with the effect of self-gravity. Adaptive mesh refinement and sink particle techniques are used to follow the long-time evolution of the shocked cloud. We find that the shock compression of a turbulent inhomogeneous molecular cloud creates massive filaments, which lie perpendicularly to the background magnetic field, as we have pointed out in a previous paper. The massive filament shows global collapse along the filament, which feeds a sink particle located at the collapse center. We observe a high accretion rate \\dot{M}_acc> 10^{-4} M_{⊙}yr-1 that is high enough to allow the formation of even O-type stars. The most massive sink particle achieves M > 50 M_{⊙} in a few times 105 yr after the onset of the filament collapse.

  7. Supervised detection of anomalous light curves in massive astronomical catalogs

    International Nuclear Information System (INIS)

    Nun, Isadora; Pichara, Karim; Protopapas, Pavlos; Kim, Dae-Won

    2014-01-01

    The development of synoptic sky surveys has led to a massive amount of data for which resources needed for analysis are beyond human capabilities. In order to process this information and to extract all possible knowledge, machine learning techniques become necessary. Here we present a new methodology to automatically discover unknown variable objects in large astronomical catalogs. With the aim of taking full advantage of all information we have about known objects, our method is based on a supervised algorithm. In particular, we train a random forest classifier using known variability classes of objects and obtain votes for each of the objects in the training set. We then model this voting distribution with a Bayesian network and obtain the joint voting distribution among the training objects. Consequently, an unknown object is considered as an outlier insofar it has a low joint probability. By leaving out one of the classes on the training set, we perform a validity test and show that when the random forest classifier attempts to classify unknown light curves (the class left out), it votes with an unusual distribution among the classes. This rare voting is detected by the Bayesian network and expressed as a low joint probability. Our method is suitable for exploring massive data sets given that the training process is performed offline. We tested our algorithm on 20 million light curves from the MACHO catalog and generated a list of anomalous candidates. After analysis, we divided the candidates into two main classes of outliers: artifacts and intrinsic outliers. Artifacts were principally due to air mass variation, seasonal variation, bad calibration, or instrumental errors and were consequently removed from our outlier list and added to the training set. After retraining, we selected about 4000 objects, which we passed to a post-analysis stage by performing a cross-match with all publicly available catalogs. Within these candidates we identified certain known

  8. Supervised Detection of Anomalous Light Curves in Massive Astronomical Catalogs

    Science.gov (United States)

    Nun, Isadora; Pichara, Karim; Protopapas, Pavlos; Kim, Dae-Won

    2014-09-01

    The development of synoptic sky surveys has led to a massive amount of data for which resources needed for analysis are beyond human capabilities. In order to process this information and to extract all possible knowledge, machine learning techniques become necessary. Here we present a new methodology to automatically discover unknown variable objects in large astronomical catalogs. With the aim of taking full advantage of all information we have about known objects, our method is based on a supervised algorithm. In particular, we train a random forest classifier using known variability classes of objects and obtain votes for each of the objects in the training set. We then model this voting distribution with a Bayesian network and obtain the joint voting distribution among the training objects. Consequently, an unknown object is considered as an outlier insofar it has a low joint probability. By leaving out one of the classes on the training set, we perform a validity test and show that when the random forest classifier attempts to classify unknown light curves (the class left out), it votes with an unusual distribution among the classes. This rare voting is detected by the Bayesian network and expressed as a low joint probability. Our method is suitable for exploring massive data sets given that the training process is performed offline. We tested our algorithm on 20 million light curves from the MACHO catalog and generated a list of anomalous candidates. After analysis, we divided the candidates into two main classes of outliers: artifacts and intrinsic outliers. Artifacts were principally due to air mass variation, seasonal variation, bad calibration, or instrumental errors and were consequently removed from our outlier list and added to the training set. After retraining, we selected about 4000 objects, which we passed to a post-analysis stage by performing a cross-match with all publicly available catalogs. Within these candidates we identified certain known

  9. Association between birth weight and objectively measured sedentary time is mediated by central adiposity

    DEFF Research Database (Denmark)

    Hildebrand, Maria; Kolle, Elin; Hansen, Bjørge H

    2015-01-01

    BACKGROUND: Birth weight is an early correlate of disease later in life, and animal studies suggest that low birth weight is associated with reduced activity and increased sedentary time. Whether birth weight predicts later sedentary time in humans is uncertain. OBJECTIVES: We examined the relation...... between birth weight and sedentary time in youth and examined whether this association was mediated by central adiposity. DESIGN: We used pooled cross-sectional data from 8 observational studies conducted between 1997 and 2007 that consisted of 10,793 youth (boys: 47%) aged 6-18 y from the International...... Children's Accelerometry Database. Birth weight was measured in hospitals or maternally reported, sedentary time was assessed by using accelerometry (

  10. Epidemiology of massive transfusion

    DEFF Research Database (Denmark)

    Halmin, M A; Chiesa, F; Vasan, S K

    2015-01-01

    and to describe characteristics and mortality of massively transfused patients. Methods: We performed a retrospective cohort study based on the Scandinavian Donations and Transfusions (SCANDAT2) database, linking data on blood donation, blood components and transfused patients with inpatient- and population.......4% among women transfused for obstetrical bleeding. Mortality increased gradually with age and among all patients massively transfused at age 80 years, only 26% were alive [TABLE PRESENTED] after 5 years. The relative mortality, early after transfusion, was high and decreased with time since transfusion...

  11. Reappraising the concept of massive transfusion in trauma

    DEFF Research Database (Denmark)

    Stanworth, Simon J; Morris, Timothy P; Gaarder, Christine

    2010-01-01

    ABSTRACT : INTRODUCTION : The massive-transfusion concept was introduced to recognize the dilutional complications resulting from large volumes of packed red blood cells (PRBCs). Definitions of massive transfusion vary and lack supporting clinical evidence. Damage-control resuscitation regimens...... of modern trauma care are targeted to the early correction of acute traumatic coagulopathy. The aim of this study was to identify a clinically relevant definition of trauma massive transfusion based on clinical outcomes. We also examined whether the concept was useful in that early prediction of massive...... transfusion as a concept in trauma has limited utility, and emphasis should be placed on identifying patients with massive hemorrhage and acute traumatic coagulopathy....

  12. SPITZER VIEW OF YOUNG MASSIVE STARS IN THE LARGE MAGELLANIC CLOUD H II COMPLEXES. II. N 159

    International Nuclear Information System (INIS)

    Chen, C.-H. Rosie; Indebetouw, Remy; Chu, You-Hua; Gruendl, Robert A.; Seale, Jonathan P.; Testor, Gerard; Heitsch, Fabian; Meixner, Margaret; Sewilo, Marta

    2010-01-01

    The H II complex N 159 in the Large Magellanic Cloud is used to study massive star formation in different environments, as it contains three giant molecular clouds (GMCs) that have similar sizes and masses but exhibit different intensities of star formation. We identify candidate massive young stellar objects (YSOs) using infrared photometry, and model their spectral energy distributions to constrain mass and evolutionary state. Good fits are obtained for less evolved Type I, I/II, and II sources. Our analysis suggests that there are massive embedded YSOs in N 159B, a maser source, and several ultracompact H II regions. Massive O-type YSOs are found in GMCs N 159-E and N 159-W, which are associated with ionized gas, i.e., where massive stars formed a few Myr ago. The third GMC, N 159-S, has neither O-type YSOs nor evidence of previous massive star formation. This correlation between current and antecedent formation of massive stars suggests that energy feedback is relevant. We present evidence that N 159-W is forming YSOs spontaneously, while collapse in N 159-E may be triggered. Finally, we compare star formation rates determined from YSO counts with those from integrated Hα and 24 μm luminosities and expected from gas surface densities. Detailed dissection of extragalactic GMCs like the one presented here is key to revealing the physics underlying commonly used star formation scaling laws.

  13. MASSIVE STARS IN THE Cl 1813-178 CLUSTER: AN EPISODE OF MASSIVE STAR FORMATION IN THE W33 COMPLEX

    International Nuclear Information System (INIS)

    Messineo, Maria; Davies, Ben; Figer, Donald F.; Trombley, Christine; Kudritzki, R. P.; Valenti, Elena; Najarro, F.; Michael Rich, R.

    2011-01-01

    Young massive (M > 10 4 M sun ) stellar clusters are a good laboratory to study the evolution of massive stars. Only a dozen of such clusters are known in the Galaxy. Here, we report about a new young massive stellar cluster in the Milky Way. Near-infrared medium-resolution spectroscopy with UIST on the UKIRT telescope and NIRSPEC on the Keck telescope, and X-ray observations with the Chandra and XMM satellites, of the Cl 1813-178 cluster confirm a large number of massive stars. We detected 1 red supergiant, 2 Wolf-Rayet stars, 1 candidate luminous blue variable, 2 OIf, and 19 OB stars. Among the latter, twelve are likely supergiants, four giants, and the faintest three dwarf stars. We detected post-main-sequence stars with masses between 25 and 100 M sun . A population with age of 4-4.5 Myr and a mass of ∼10, 000 M sun can reproduce such a mixture of massive evolved stars. This massive stellar cluster is the first detection of a cluster in the W33 complex. Six supernova remnants and several other candidate clusters are found in the direction of the same complex.

  14. Conflicts between Fulani Herders and Farmers in Central and ...

    African Journals Online (AJOL)

    Due to climate change, to massive land acquisitions by capitalist farmers, and mainly, to the perpetuation of the pastoral way of life in Nigeria, there has been a great increase in the presence of Fulani herders in central and southern Nigeria. This has resulted in frequent conflicts between the herders and farming ...

  15. Traumatic pseudoaneurysm of the intracavernous ICA presenting with massive epistaxis: imaging diagnosis and endovascular treatment.

    Science.gov (United States)

    Han, M H; Sung, M W; Chang, K H; Min, Y G; Han, D H; Han, M C

    1994-03-01

    Traumatic pseudoaneurysm of the intracavernous internal carotid artery (ICA) is a very rare cause of epistaxis but is a life-threatening clinical situation when left untreated. The authors have experienced four cases of traumatic pseudoaneurysm involving the intracavernous ICA. Delayed massive epistaxes developed 1 to 8 months after trauma and initial transient epistaxis in all four patients. Three of the cases were successfully managed by the detachable balloon occlusion (DBO) of the ICA along with the aneurysm openings. In one case, a large pseudoaneurysm destroying a large area of the central skull base with peripheral blood clot was demonstrated on computed tomography, magnetic resonance imaging, and angiography; this patient died due to massive epistaxis before the trial of DBO. Imaging findings of pseudoaneurysms involving the intracavernous ICA in the four cases are described, and the role of endovascular treatment is discussed.

  16. LINEAR POLARIZATION OF CLASS I METHANOL MASERS IN MASSIVE STAR-FORMING REGIONS

    International Nuclear Information System (INIS)

    Kang, Ji-hyun; Byun, Do-Young; Kim, Kee-Tae; Kim, Jongsoo; Lyo, A-Ran; Vlemmings, W. H. T.

    2016-01-01

    Class I methanol masers are found to be good tracers of the interaction between outflows from massive young stellar objects with their surrounding media. Although polarization observations of Class II methanol masers have been able to provide information about magnetic fields close to the central (proto)stars, polarization observations of Class I methanol masers are rare, especially at 44 and 95 GHz. We present the results of linear polarization observations of 39 Class I methanol maser sources at 44 and 95 GHz. These two lines are observed simultaneously with one of the 21 m Korean VLBI Network telescopes in single-dish mode. Approximately 60% of the observed sources have fractional polarizations of a few percent in at least one transition. This is the first reported detection of linear polarization of the 44 GHz methanol maser. The two maser transitions show similar polarization properties, indicating that they trace similar magnetic environments, although the fraction of the linear polarization is slightly higher at 95 GHz. We discuss the association between the directions of polarization angles and outflows. We also discuss some targets having different polarization properties at both lines, including DR21(OH) and G82.58+0.20, which show the 90° polarization angle flip at 44 GHz.

  17. Massive target nuclei as disc-shaped slabs and spherical objects of intranuclear matter in high-energy nuclear collisions

    International Nuclear Information System (INIS)

    Zewislawski, Z.; Strugalski, Z.; Mausa, M.

    1990-01-01

    It has been found experimentally that a definite number of emitted nucleons corresponds to a definite impact parameter in hadron-nucleus collisions. This finding allows one: to treat the massive target nucleus as a piece of intranuclear matter of a definite thickness; to treat a numerous sample of collisions of monoenergetic identical hadrons with the nucleus as collection of interactions of a homogeneous beam of hadrons with disc-shaped slabs of intranuclear matter of definite thicknesses. 17 refs.; 1 fig

  18. How I treat patients with massive hemorrhage

    DEFF Research Database (Denmark)

    Johansson, Pär I; Stensballe, Jakob; Oliveri, Roberto

    2014-01-01

    Massive hemorrhage is associated with coagulopathy and high mortality. The transfusion guidelines up to 2006 recommended that resuscitation of massive hemorrhage should occur in successive steps using crystalloids, colloids and red blood cells (RBC) in the early phase, and plasma and platelets...... in the late phase. With the introduction of the cell-based model of hemostasis in the mid 1990ties, our understanding of the hemostatic process and of coagulopathy has improved. This has contributed to a change in resuscitation strategy and transfusion therapy of massive hemorrhage along with an acceptance...... outcome, although final evidence on outcome from randomized controlled trials are lacking. We here present how we in Copenhagen and Houston, today, manage patients with massive hemorrhage....

  19. Massive star formation by accretion. II. Rotation: how to circumvent the angular momentum barrier?

    Science.gov (United States)

    Haemmerlé, L.; Eggenberger, P.; Meynet, G.; Maeder, A.; Charbonnel, C.; Klessen, R. S.

    2017-06-01

    Context. Rotation plays a key role in the star-formation process, from pre-stellar cores to pre-main-sequence (PMS) objects. Understanding the formation of massive stars requires taking into account the accretion of angular momentum during their PMS phase. Aims: We study the PMS evolution of objects destined to become massive stars by accretion, focusing on the links between the physical conditions of the environment and the rotational properties of young stars. In particular, we look at the physical conditions that allow the production of massive stars by accretion. Methods: We present PMS models computed with a new version of the Geneva Stellar Evolution code self-consistently including accretion and rotation according to various accretion scenarios for mass and angular momentum. We describe the internal distribution of angular momentum in PMS stars accreting at high rates and we show how the various physical conditions impact their internal structures, evolutionary tracks, and rotation velocities during the PMS and the early main sequence. Results: We find that the smooth angular momentum accretion considered in previous studies leads to an angular momentum barrier and does not allow the formation of massive stars by accretion. A braking mechanism is needed in order to circumvent this angular momentum barrier. This mechanism has to be efficient enough to remove more than two thirds of the angular momentum from the inner accretion disc. Due to the weak efficiency of angular momentum transport by shear instability and meridional circulation during the accretion phase, the internal rotation profiles of accreting stars reflect essentially the angular momentum accretion history. As a consequence, careful choice of the angular momentum accretion history allows circumvention of any limitation in mass and velocity, and production of stars of any mass and velocity compatible with structure equations.

  20. Effect of Haemostatic Control Resuscitation on mortality in massively bleeding patients: a before and after study

    DEFF Research Database (Denmark)

    Johansson, P I; Stensballe, J

    2009-01-01

    BACKGROUND AND OBJECTIVES: Evidence supporting the use of platelets and plasma in resuscitation of massive bleedings is questionable. Current consensus guidelines recommend restrictive use. Our aim was to determine the effect of changing the transfusion practice on 30-day survival in massively...... bleeding patients. MATERIALS AND METHODS: Consecutive adult patients receiving more than 10 units of red blood cells (RBC) within 24 h 2 years prior to (2002-2003) and 2 years after (2005-2006) a change in transfusion practice were included. In 2004, we implemented Haemostatic Control Resuscitation (HCR......) with preemptive use of platelets and plasma, administered in transfusion packages, comprising 5 units of RBCs, 5 units of fresh-frozen plasma and 2 units of platelet concentrates (PC), when massive bleeding occurred or upon arrival at the emergency room and thereafter directed by thrombelastography throughout...

  1. On the singularities of massive superstring amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Foda, O.

    1987-06-04

    Superstring one-loop amplitudes with massive external states are shown to be in general ill-defined due to internal on-shell propagators. However, we argue that since any massive string state (in the uncompactified theory) has a finite lifetime to decay into massless particles, such amplitudes are not terms in the perturbative expansion of physical S-matrix elements: These can be defined only with massless external states. Consistent massive amplitudes repuire an off-shell formalism.

  2. Massive supermultiplets in four-dimensional superstring theory

    International Nuclear Information System (INIS)

    Feng Wanzhe; Lüst, Dieter; Schlotterer, Oliver

    2012-01-01

    We extend the discussion of Feng et al. (2011) on massive Regge excitations on the first mass level of four-dimensional superstring theory. For the lightest massive modes of the open string sector, universal supermultiplets common to all four-dimensional compactifications with N=1,2 and N=4 spacetime supersymmetry are constructed respectively - both their vertex operators and their supersymmetry variations. Massive spinor helicity methods shed light on the interplay between individual polarization states.

  3. Super selective transcatheter angiographic embolization: an effective and prophylactic treatment for massive obstetric haemorrhage

    International Nuclear Information System (INIS)

    Zhou Yiming; Zhai Renyou; Qian Xiaojun; Wei Baojie; Gao Kun; Zhang Shilong; Liu Jinmei; Zhang Qiuhong; Jiang Lei

    2008-01-01

    Objective: To discuss the effect and safety of transcatheter angiographic embolization (TAE)for managing massive obstetric haemorrhage. Methods: 17 cases of obstetric massive haemorrhage or with haemorrhage tendency were treated with TAE. Among them 14 cases had haemorrhage already, including 10 cases after abortion, caesarean section or normal labor and other 4 of hydatidiform mole. 3 cases with obstetric haemorrhage tendency included 2 cases of placenta praevia and 1 case of cervical pregnancy. Selective catheterization into bilateral uterine arteries or internal iliac arteries for DSA, showed the cause and location of the haemorrhage and then embolized with gelfoam sponge chips (1-3 mm) or Polyvinyl Alcohol(PVA); and part of the cases with MTX through uterine arterial perfusion. Results: The successful rate of catheterization was 100%. The achievement in 14 cases showed no active haemorrhage immediately after the procedure and no vaginal bleeding after 1-5 days. In 3 prophylactic cases before abortion or uterine curettage, obstetric massive haemorrhage occurred in 1 case, but not so in other 2 cases. Conclusions: TAE is an effective treatment for obstetric massive haemorrhage, with the advantages of minimal trauma, fast and definite treating effect and less complications. Prophylactical application for high risk patients can reduce the bleeding and mortality. (authors)

  4. The HST/ACS Coma Cluster Survey - VII. Structure and assembly of massive galaxies in the centre of the Coma cluster

    NARCIS (Netherlands)

    Weinzirl, Tim; Jogee, Shardha; Neistein, Eyal; Khochfar, Sadegh; Kormendy, John; Marinova, Irina; Hoyos, Carlos; Balcells, Marc; den Brok, Mark; Hammer, Derek; Peletier, Reynier F.; Kleijn, Gijs Verdoes; Carter, David; Goudfrooij, Paul; Lucey, John R.; Mobasher, Bahram; Trentham, Neil; Erwin, Peter; Puzia, Thomas

    2014-01-01

    We constrain the assembly history of galaxies in the projected central 0.5 Mpc of the Coma cluster by performing structural decomposition on 69 massive (M⋆ ≥ 109 M⊙) galaxies using high-resolution F814W images from the Hubble Space Telescope (HST) Treasury Survey of Coma. Each galaxy is modelled

  5. Update on massive transfusion.

    Science.gov (United States)

    Pham, H P; Shaz, B H

    2013-12-01

    Massive haemorrhage requires massive transfusion (MT) to maintain adequate circulation and haemostasis. For optimal management of massively bleeding patients, regardless of aetiology (trauma, obstetrical, surgical), effective preparation and communication between transfusion and other laboratory services and clinical teams are essential. A well-defined MT protocol is a valuable tool to delineate how blood products are ordered, prepared, and delivered; determine laboratory algorithms to use as transfusion guidelines; and outline duties and facilitate communication between involved personnel. In MT patients, it is crucial to practice damage control resuscitation and to administer blood products early in the resuscitation. Trauma patients are often admitted with early trauma-induced coagulopathy (ETIC), which is associated with mortality; the aetiology of ETIC is likely multifactorial. Current data support that trauma patients treated with higher ratios of plasma and platelet to red blood cell transfusions have improved outcomes, but further clinical investigation is needed. Additionally, tranexamic acid has been shown to decrease the mortality in trauma patients requiring MT. Greater use of cryoprecipitate or fibrinogen concentrate might be beneficial in MT patients from obstetrical causes. The risks and benefits for other therapies (prothrombin complex concentrate, recombinant activated factor VII, or whole blood) are not clearly defined in MT patients. Throughout the resuscitation, the patient should be closely monitored and both metabolic and coagulation abnormalities corrected. Further studies are needed to clarify the optimal ratios of blood products, treatment based on underlying clinical disorder, use of alternative therapies, and integration of laboratory testing results in the management of massively bleeding patients.

  6. The internal/external issue what is an outer object? Another person as object and as separate other in object relations models.

    Science.gov (United States)

    Zachrisson, Anders

    2013-01-01

    The question of what we mean by the term outer object has its roots in the epistemological foundation of psychoanalysis. From the very beginning, Freud's view was Kantian, and psychoanalysis has kept that stance, as it seems. The author reviews the internal/external issue in Freud's thinking and in the central object relations theories (Klein, Winnicott, and Bion). On this background he proposes a simple model to differentiate the concept of object along one central dimension: internal object, external object, and actual person. The main arguments are: (1) there is no direct, unmediated perception of the actual person--the experience of the other is always affected by the perceiver's subjectivity; (2) in intense transference reactions and projections, the perception of the person is dominated by the qualities of an inner object--and the other person "becomes" an external object for the perceiver; (3) when this distortion is less dominating, the other person to a higher degree remains a separate other--a person in his or her own right. Clinical material illustrates these phenomena, and a graphical picture of the model is presented. Finally with the model as background, the author comments on a selection of phenomena and concepts such as unobjectionable transference, "the third position," mourning and loneliness. The way that the internal colours and distorts the external is of course a central preoccupation of psychoanalysis generally. (Spillius et al., 2011, p. 326)

  7. Massive lepton pair production in massive quantum electrodynamics

    International Nuclear Information System (INIS)

    Raychaudhuri, P.

    1976-01-01

    The pp → l + +l - +x inclusive interaction has been studied at high energies in terms of the massive quantum electrodynamics. The differential cross-section (dsigma/dQ 2 ) is derived and proves to be proportional to Q -4 , where Q-mass of the lepton pair. Basic features of the cross-section are demonstrated to be consistent with the Drell-Yan model

  8. THE EUROPEAN CENTRAL BANK AND THE EUROZONE CRISIS MANAGEMENT

    Directory of Open Access Journals (Sweden)

    MONICA ŞAGUNA

    2013-05-01

    Full Text Available The Euro is the single currency shared by 17 of the European Union's Member States, which together make up the Euro area. Since its introduction, in January 2002, it became the second most traded currency in the world after the United States dollar. With the launch of the Euro, the monetary policy became the responsibility of the independent European Central Bank, which was created for that purpose, and of the national central banks of the Member States, having adopted the Euro. However, the accumulation of massive and unsustainable deficits and public debt levels in a number of peripheral economies threatened the Eurozone's viability by the end of its first decade, triggering a Eurozone sovereign debt crisis. The institutional mechanisms surrounding the Euro have also been an integral part of the crisis. On this line, the European Monetary Union is supported on one side by treaties and multilateral agreements including the Maastricht Treaty, the Stability and Growth Pact and the Lisbon Strategy and, on the other side, by the European Central Bank. The combination of these institutions has produced a mix of monetary, fiscal and labour market policies with powerful social implications. And, what started as a debt crisis in Greece in late 2009 has evolved into a broader economic and political crisis in the Eurozone and European Union. In this framework, the purpose of my paper is to analyze the roots of the Eurozone crisis, as the biggest challenge since the Euro adoption and the European Central Bank’s response to it. Therefore the objectives are: identification of the reasons that stand behind the crisis, then observing how the crisis has affected the functioning of the European Central Bank and the Euro, and how it was forced to respond and, finally, focusing on the future and the challenges that lie ahead.

  9. Intelligent trigger by massively parallel processors for high energy physics experiments

    International Nuclear Information System (INIS)

    Rohrbach, F.; Vesztergombi, G.

    1992-01-01

    The CERN-MPPC collaboration concentrates its effort on the development of machines based on massive parallelism with thousands of integrated processing elements, arranged in a string. Seven applications are under detailed studies within the collaboration: three for LHC, one for SSC, two for fixed target high energy physics at CERN and one for HDTV. Preliminary results are presented. They show that the objectives should be reached with the use of the ASP architecture. (author)

  10. Epidemiology of Massive Transfusion

    DEFF Research Database (Denmark)

    Halmin, Märit; Chiesa, Flaminia; Vasan, Senthil K

    2016-01-01

    in Sweden from 1987 and in Denmark from 1996. A total of 92,057 patients were included. Patients were followed until the end of 2012. MEASUREMENTS AND MAIN RESULTS: Descriptive statistics were used to characterize the patients and indications. Post transfusion mortality was expressed as crude 30-day...... mortality and as long-term mortality using the Kaplan-Meier method and using standardized mortality ratios. The incidence of massive transfusion was higher in Denmark (4.5 per 10,000) than in Sweden (2.5 per 10,000). The most common indication for massive transfusion was major surgery (61.2%) followed...

  11. On the singularities of massive superstring amplitudes

    International Nuclear Information System (INIS)

    Foda, O.

    1987-01-01

    Superstring one-loop amplitudes with massive external states are shown to be in general ill-defined due to internal on-shell propagators. However, we argue that since any massive string state (in the uncompactified theory) has a finite lifetime to decay into massless particles, such amplitudes are not terms in the perturbative expansion of physical S-matrix elements: These can be defined only with massless external states. Consistent massive amplitudes repuire an off-shell formalism. (orig.)

  12. Starbursts triggered by central overpressure in interacting galaxies

    Science.gov (United States)

    Jog, Chanda J.; Das, Mousumi

    1993-01-01

    A triggering mechanism for the origin of enhanced, massive-star formation in the central regions of interacting spiral galaxy pairs is proposed. Our mechanism is based on the detailed evolution of a realistic interstellar medium in a galaxy following an encounter. As a disk giant molecular cloud (GMC) tumbles into the central region following a galaxy encounter, it undergoes a radiative shock compression via the pre-existing high pressure of the central intercloud medium. The shocked outer shell of a GMC becomes gravitationally unstable and begins to fragment thus resulting in a burst of star formation, when the growth time for the gravitational instabilities in the shell becomes smaller than the crossing time of the shock. The resulting values of typical infrared luminosity agree with observations.

  13. Developing a Massively Parallel Forward Projection Radiography Model for Large-Scale Industrial Applications

    Energy Technology Data Exchange (ETDEWEB)

    Bauerle, Matthew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-08-01

    This project utilizes Graphics Processing Units (GPUs) to compute radiograph simulations for arbitrary objects. The generation of radiographs, also known as the forward projection imaging model, is computationally intensive and not widely utilized. The goal of this research is to develop a massively parallel algorithm that can compute forward projections for objects with a trillion voxels (3D pixels). To achieve this end, the data are divided into blocks that can each t into GPU memory. The forward projected image is also divided into segments to allow for future parallelization and to avoid needless computations.

  14. Thermodynamics inducing massive particles' tunneling and cosmic censorship

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Baocheng [Chinese Academy of Sciences, State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Wuhan (China); Graduate University of Chinese Academy of Sciences, Beijing (China); Cai, Qing-yu [Chinese Academy of Sciences, State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Wuhan (China); Zhan, Ming-sheng [Chinese Academy of Sciences, State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Wuhan (China); Chinese Academy of Sciences, Center for Cold Atom Physics, Wuhan (China)

    2010-08-15

    By calculating the change of entropy, we prove that the first law of black hole thermodynamics leads to the tunneling probability of massive particles through the horizon, including the tunneling probability of massive charged particles from the Reissner-Nordstroem black hole and the Kerr-Newman black hole. Novelly, we find the trajectories of massive particles are close to that of massless particles near the horizon, although the trajectories of massive charged particles may be affected by electromagnetic forces. We show that Hawking radiation as massive particles tunneling does not lead to violation of the weak cosmic-censorship conjecture. (orig.)

  15. 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

  16. Bronchial artery embolization in the treatment of massive hemoptysis

    International Nuclear Information System (INIS)

    Zubairi, Ali Bin Sarwar; Zubairi, M.A.; Irfan, M.; Tanveer-ul-Haq; Fatima, K.; Azeemuddin, M.

    2007-01-01

    Objective was to evaluate the efficacy of bronchial arteriography and bronchial artery embolization (BAE) in the management of massive hemoptysis in a developing Asian country. A retrospective review was carried out from March 2000 to March 2005 to evaluate the demographics, clinical presentation, radiographic studies, bronchoscopy results, and complications of bronchial arteriography and BAE at a tertiary care hospital in Pakistan. Fourteen patients (9males, 5 females) with a mean age of 49 years underwent bronchial arteriography and BAE for massive hemoptysis. Hemoptysis was caused by bronchiectasis (10 patients), active pulmonary tuberculosis (3 patients), and lung malignancy (one patient). A CT scan of the chest was carried out in 11 patients, which revealed bronchiectasis (8 patients), cavity with infiltrates (3 patients), and mass lesion (one patient). Bronchoscopy was performed in all patients. Bleeding lobe or segment was identified in 12 patients. Bronchial arteriography revealed hypervascularity (13 patients), bronchial artery hypertrophy (5 patients), hypervascularity with shunting (one patient), dense soft tissue staining (7 patients), extravasation of contrast (one patient) pseudoaneurysm (one patient). Bronchial artery embolization was carried out in all patients. Rebleeding occurred within 24 hours in 2 patients who underwent surgery and within one week another 2 patients who were managed with repeat BAE. The complication of embolization occurred in one patient (transverse myelitis). Thirteen patients improved and were discharged home. One patient with terminal lung carcinoma died due to cardiogenic shock secondary to acute myocardial infarction. Bronchial artery embolization is an effective method for management of massive hemoptysis in developing countries and has a low complication rate. (author)

  17. Radiotherapy in massive angiomatous osteolysis (Gorham-Stout's syndrome)

    International Nuclear Information System (INIS)

    Bek, V.; Haicl, Z.; Kolar, J.; Bednar, B.; Karlova Universita, Prague; Institute for Postgraduate Medical and Pharmaceutical Studies, Prague; Karlova Universita, Prague

    1981-01-01

    The cases of two young men with the Gorham-Stout's syndrome of massive angiomatous osteolysis are presented. Attempted surgical removal of the pathological angiomatous tissue proved unsuccessful. Telegammatherapy with each patient receiving total focal dose of 40.0 Gy fractionated over a period of 4 weeks resulted in speedy and complete arrest of osteolysis, and in partial recalcification of the bone tissue destroyed. In one patient the favourable condition has been lasting for 9 years, in the other for 8 months from the end of the course of radiotherapy. The authors discuss the cause of a central fracture of the first patient's left acetabulum which was noted 5 years after the radiotherapy. Proceeding from their experience so far, the authors describe radiotherapy in the Gorham-Stout's syndrome as a method of choice, and give a list of the therapeutical principles. (orig.) [de

  18. Exact Solutions in 3D New Massive Gravity

    Science.gov (United States)

    Ahmedov, Haji; Aliev, Alikram N.

    2011-01-01

    We show that the field equations of new massive gravity (NMG) consist of a massive (tensorial) Klein-Gordon-type equation with a curvature-squared source term and a constraint equation. We also show that, for algebraic type D and N spacetimes, the field equations of topologically massive gravity (TMG) can be thought of as the “square root” of the massive Klein-Gordon-type equation. Using this fact, we establish a simple framework for mapping all types D and N solutions of TMG into NMG. Finally, we present new examples of types D and N solutions to NMG.

  19. Caught in the rhythm. I. How satellites settle into a plane around their central galaxy

    Science.gov (United States)

    Welker, C.; Dubois, Y.; Pichon, C.; Devriendt, J.; Chisari, N. E.

    2018-05-01

    Context. The anisotropic distribution of satellites around the central galaxy of their host halo is both well-documented in observations and predicted by the ΛCDM model. However its amplitude, direction and possible biases associated to the specific dynamics of such satellite galaxies are still highly debated. Aims: Using the cosmological hydrodynamics simulation Horizon-AGN, we aim to quantify the anisotropy of the spatial distribution of satellite galaxies relative to their central counterpart and explore its connexion to the local cosmic web, in the redshift range between 0.3 and 0.8. Methods: Haloes and galaxies were identified and their kinematics computed using their dark matter and stellar particles respectively. Sub-haloes were discarded and galaxies lying within 5 Rvir of a given halo are matched to it. The filamentary structure of the cosmic web was extracted from the density field - smoothed over a 3 h-1 Mpc typical scale - as a network of contiguous segments. We then investigated the distribution function of relevant angles, most importantly the angle α between the central-to-satellite separation vector and the group's nearest filament, aside with the angle between this same separation and the central minor axis. This allowed us to explore the correlations between filamentary infall, intra-cluster inspiralling and the resulting distribution of satellites around their central counterpart. Results: We find that, on average, satellites tend to be located on the galactic plane of the central object. This effect is detected for central galaxies with a stellar mass larger than 1010 M⊙ and found to be strongest for red passive galaxies, while blue galaxies exhibit a weaker trend. For galaxies with a minor axis parallel to the direction of the nearest filament, we find that the coplanarity is stronger in the vicinity of the central galaxy, and decreases when moving towards the outskirts of the host halo. By contrast, the spatial distribution of satellite

  20. Spacetime structure of massive Majorana particles and massive gravitino

    CERN Document Server

    Ahluwalia, D V

    2003-01-01

    The profound difference between Dirac and Majorana particles is traced back to the possibility of having physically different constructs in the (1/2, 0) 0 (0,1/2) representation space. Contrary to Dirac particles, Majorana-particle propagators are shown to differ from the simple linear gamma mu p submu, structure. Furthermore, neither Majorana particles, nor their antiparticles can be associated with a well defined arrow of time. The inevitable consequence of this peculiarity is the particle-antiparticle metamorphosis giving rise to neutrinoless double beta decay, on the one side, and enabling spin-1/2 fields to act as gauge fields, gauginos, on the other side. The second part of the lecture notes is devoted to massive gravitino. We argue that a spin measurement in the rest frame for an unpolarized ensemble of massive gravitino, associated with the spinor-vector [(1/2, 0) 0 (0,1/2)] 0 (1/2,1/2) representation space, would yield the results 3/2 with probability one half, and 1/2 with probability one half. The ...

  1. Conceptual Distinctiveness Supports Detailed Visual Long-Term Memory for Real-World Objects

    Science.gov (United States)

    Konkle, Talia; Brady, Timothy F.; Alvarez, George A.; Oliva, Aude

    2010-01-01

    Humans have a massive capacity to store detailed information in visual long-term memory. The present studies explored the fidelity of these visual long-term memory representations and examined how conceptual and perceptual features of object categories support this capacity. Observers viewed 2,800 object images with a different number of exemplars…

  2. Massive vector fields and black holes

    International Nuclear Information System (INIS)

    Frolov, V.P.

    1977-04-01

    A massive vector field inside the event horizon created by the static sources located outside the black hole is investigated. It is shown that the back reaction of such a field on the metric near r = 0 cannot be neglected. The possibility of the space-time structure changing near r = 0 due to the external massive field is discussed

  3. Optimizing mission critical data dissemination in massive IoT networks

    KAUST Repository

    Farooq, Muhammad Junaid

    2017-06-29

    Mission critical data dissemination in massive Internet of things (IoT) networks imposes constraints on the message transfer delay between devices. Due to low power and communication range of IoT devices, data is foreseen to be relayed over multiple device-to-device (D2D) links before reaching the destination. The coexistence of a massive number of IoT devices poses a challenge in maximizing the successful transmission capacity of the overall network alongside reducing the multi-hop transmission delay in order to support mission critical applications. There is a delicate interplay between the carrier sensing threshold of the contention based medium access protocol and the choice of packet forwarding strategy selected at each hop by the devices. The fundamental problem in optimizing the performance of such networks is to balance the tradeoff between conflicting performance objectives such as the spatial frequency reuse, transmission quality, and packet progress towards the destination. In this paper, we use a stochastic geometry approach to quantify the performance of multi-hop massive IoT networks in terms of the spatial frequency reuse and the transmission quality under different packet forwarding schemes. We also develop a comprehensive performance metric that can be used to optimize the system to achieve the best performance. The results can be used to select the best forwarding scheme and tune the carrier sensing threshold to optimize the performance of the network according to the delay constraints and transmission quality requirements.

  4. Collapsing supra-massive magnetars: FRBs, the repeating FRB121102 and GRBs

    Science.gov (United States)

    Gupta, Patrick Das; Saini, Nidhi

    2018-02-01

    Fast Radio Bursts (FRBs) last for ˜ few milli-seconds and, hence, are likely to arise from the gravitational collapse of supra-massive, spinning neutron stars after they lose the centrifugal support (Falcke & Rezzolla 2014). In this paper, we provide arguments to show that the repeating burst, FRB 121102, can also be modeled in the collapse framework provided the supra-massive object implodes either into a Kerr black hole surrounded by highly magnetized plasma or into a strange quark star. Since the estimated rates of FRBs and SN Ib/c are comparable, we put forward a common progenitor scenario for FRBs and long GRBs in which only those compact remnants entail prompt γ -emission whose kick velocities are almost aligned or anti-aligned with the stellar spin axes. In such a scenario, emission of detectable gravitational radiation and, possibly, of neutrinos are expected to occur during the SN Ib/c explosion as well as, later, at the time of magnetar implosion.

  5. Trees or Grids? Indexing Moving Objects in Main Memory

    DEFF Research Database (Denmark)

    Sidlauskas, Darius; Saltenis, Simonas; Christiansen, Christian Winther

    2009-01-01

    New application areas, such as location-based services, rely on the efficient management of large collections of mobile objects. Maintaining accurate, up-to-date positions of these objects results in massive update loads that must be supported by spatial indexing structures and main-memory indexes...... are usually necessary to provide high update performance. Traditionally, the R-tree and its variants were used for indexing spatial data, but most of the recent research assumes that a simple, uniform grid is the best choice for managing moving objects in main memory. We perform an extensive experimental...

  6. Abell 48 - a rare WN-type central star of a planetary nebula

    Science.gov (United States)

    Todt, H.; Kniazev, A. Y.; Gvaramadze, V. V.; Hamann, W.-R.; Buckley, D.; Crause, L.; Crawford, S. M.; Gulbis, A. A. S.; Hettlage, C.; Hooper, E.; Husser, T.-O.; Kotze, P.; Loaring, N.; Nordsieck, K. H.; O'Donoghue, D.; Pickering, T.; Potter, S.; Romero-Colmenero, E.; Vaisanen, P.; Williams, T.; Wolf, M.

    2013-04-01

    A considerable fraction of the central stars of planetary nebulae (CSPNe) are hydrogen-deficient. Almost all of these H-deficient central stars (CSs) display spectra with strong carbon and helium lines. Most of them exhibit emission-line spectra resembling those of massive WC stars. Therefore these stars are classed as CSPNe of spectral type [WC]. Recently, quantitative spectral analysis of two emission-line CSs, PB 8 and IC 4663, revealed that these stars do not belong to the [WC] class. Instead PB 8 has been classified as [WN/WC] type and IC 4663 as [WN] type. In this work we report the spectroscopic identification of another rare [WN] star, the CS of Abell 48. We performed a spectral analysis of Abell 48 with the Potsdam Wolf-Rayet (PoWR) models for expanding atmospheres. We find that the expanding atmosphere of Abell 48 is mainly composed of helium (85 per cent by mass), hydrogen (10 per cent) and nitrogen (5 per cent). The residual hydrogen and the enhanced nitrogen abundance make this object different from the other [WN] star IC 4663. We discuss the possible origin of this atmospheric composition.

  7. Emergency transcatheter arterial embolization for critical massive bleeding due to duodenal bulb ulcer

    International Nuclear Information System (INIS)

    Li Qiang; Li Yiyun; Zhao Chunmei

    2011-01-01

    Objective: To evaluate the efficacy and feasibility of emergency transcatheter arterial embolization (ETAE) in treating critical massive bleeding due to duodenal bulb ulcer. Methods: ETAE was carried out in seven patients with acute massive bleeding due to endoscopically-proved duodenal bulb ulcer, who failed to respond conservative measures and were critically ill clinically. Super-selective catheterization of gastroduodenal artery or right gastroepiploic artery was performed, which was followed by arterial angiography to identify the bleeding site. According to the angiographic findings, ETAE with Gelfoam particles and coils was carried out. After the operation medical management was given and endoscopy re-examination was conducted. All the patients were follow up for 3∼6 months. Results: Angiographically, gastroduodenal artery bleeding was detected in all seven patients. ETAE was successfully accomplished in all cases. Complete clinical effectiveness was obtained in six patients while partial effectiveness in one case. No procedure-related complications occurred. Conclusion: For critical massive bleeding due to duodenal bulb ulcer ETAE is a highly effective and safe treatment, which can be regarded as an alternative to surgery. It is worth popularizing this technique in clinical practice. (authors)

  8. DSA findings and bronchial arterial embolization of bronchiectasis with massive hemoptysis

    International Nuclear Information System (INIS)

    Xu Guobin; Liu Junfang; Hu Jinxiang; Long Qingyun

    2008-01-01

    Objective: To explore DSA findings curative measures and effects of bronchial arterial embolization (BAE)of bronchiectasis with massive hemoptysis. Methods: 35 patients with massive hemoptysis due to bronchiectasis were performed selective bronchial arterial DSA and BAE referring to image data of chest plain film and CT. Embolic materials were polyvinyl alcohol (PVA)and/or gelatinum sponge particles. Curative effects were followed-up for 3 months to 3 years. Results: (1)DSA revealed bronchial artery as being the only abnormal vessel accounted for 74.3%, bronchial artry combined with nonbronchial systemic artery as 22.9% and only non-bronchial artery involved 2.9%. Abnormal vessel number was 1-5 (mean 1.8) per case; Direct and indirect bleeding sign was displayed as 25.7% and 100% respectively. (2)Curative and embolization effects were shown as 61 target vessels of 34 patients being embolized and total effective rate reaching 85.3%; of which 16 cases were adopted super-selective technique, 1 case was failure of stopping bleeding for two times within 3 days, 4 cases recurred within 3 months and 2 cases recurred over 3 months; with recurrent rate of 20.6%, but no serious complications such as spinal cord injury. Conclusions: DSA examination and selective BAE of bronchiectasis with massive hemoptysis could provide high positive angiographic features and reliable curative effect. (authors)

  9. Demonstration of massive hydraulic fracturing Piceance Basin, Rio Blanco County, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Fitch, J L; Medlin, W L; Strubhar, M K

    1979-08-01

    Demonstration of massive fracturing to provide gas production from tight gas sands in the Piceance Basin was the objective of this jointly funded Mobil DOE project. This effort has been at least partially successful. The uppermost interval fractured, the Ohio Creek formation at 7324 to 7476 ft, appears to be commercially viable. The remaining sequence to total depth of 10,800 ft may also be commercially attractive, depending on fractured well costs, gas prices and the risk of failure to achieve production capacity equal to, or greater than, that achieved in the present well. Prior work was performed by Mobil in the Brush Creek Unit, Mesa County, Colorado. One well, Brush Creek 1-25, was drilled to 10,330 ft and given two massive fracturing treatments before the well was plugged and abandoned as noncommercial. It was concluded that formation permeability was too low to justify additional work in the Brush Creek Unit. Piceance Creek well F31-13G was drilled to 10,800 ft. Nine zones were tested in the Mesaverde and Ohio Creek formations between 7324 to 10,680 ft. Six massive fracturing treatments were performed covering 7 of the 9 intervals. Average first-year flow potential of the well is estimated at 2.9 MMCF/day with 1.1 MMCF/day of this amount attributed to the uppermost zone.

  10. Investigation of the status quo of massive blood transfusion in China and a synopsis of the proposed guidelines for massive blood transfusion.

    Science.gov (United States)

    Yang, Jiang-Cun; Wang, Qiu-Shi; Dang, Qian-Li; Sun, Yang; Xu, Cui-Xiang; Jin, Zhan-Kui; Ma, Ting; Liu, Jing

    2017-08-01

    The aim of this study was to provide an overview of massive transfusion in Chinese hospitals, identify the important indications for massive transfusion and corrective therapies based on clinical evidence and supporting experimental studies, and propose guidelines for the management of massive transfusion. This multiregion, multicenter retrospective study involved a Massive Blood Transfusion Coordination Group composed of 50 clinical experts specializing in blood transfusion, cardiac surgery, anesthesiology, obstetrics, general surgery, and medical statistics from 20 tertiary general hospitals across 5 regions in China. Data were collected for all patients who received ≥10 U red blood cell transfusion within 24 hours in the participating hospitals from January 1 2009 to December 31 2010, including patient demographics, pre-, peri-, and post-operative clinical characteristics, laboratory test results before, during, and after transfusion, and patient mortality at post-transfusion and discharge. We also designed an in vitro hemodilution model to investigate the changes of blood coagulation indices during massive transfusion and the correction of coagulopathy through supplement blood components under different hemodilutions. The experimental data in combination with the clinical evidence were used to determine the optimal proportion and timing for blood component supplementation during massive transfusion. Based on the findings from the present study, together with an extensive review of domestic and international transfusion-related literature and consensus feedback from the 50 experts, we drafted the guidelines on massive blood transfusion that will help Chinese hospitals to develop standardized protocols for massive blood transfusion.

  11. Evolution of a massive binary in a star field

    International Nuclear Information System (INIS)

    Baranov, A.S.

    1984-01-01

    The orbital evolution of a massive binary system interacting with a background field of single stars whose phase density is homogeneous in configuration space is considered. The velocity distribution is assumed isotropic up to some limiting value, and a typical field star is regarded as having a velocity much higher than the orbital speed of the pair components. An expression is derived for the transfer of energy from the binary to the field stars. The time evolution of the orbit parameters a, e is established, and the evolution rate is estimated for Kardashev's (1983) model galactic nucleus containing a central black-hole binary. On the above assumptions the components should become twice as close together within only a few tens of millennia, although the picture may change fundamentally if the nucleus is rotating. 13 references

  12. Evolution of massive stars with mass loss: surface abundances

    International Nuclear Information System (INIS)

    Greggio, L.

    1984-01-01

    The location of theoretical stellar models in the upper part of the Hertzsprung-Russell diagram depends on a variety of poorly understood physical processes which may occur during the evolution of massive stars. The comparison between theoretical predictions and observations of the surface chemical composition of these objects can help in understanding their evolution and to set more stringent limits to the mentioned parameters. To this end, evolutionary sequences corresponding to 20, 40 and 60 solar masses have been computed up to core He exhaustion, following in detail the abundance variations of CNO, Ne and Mg isotopes. (Auth.)

  13. Management of massive haemoptysis | Adegboye | Nigerian Journal ...

    African Journals Online (AJOL)

    Background: This study compares two management techniques in the treatment of massive haemotysis. Method: All patients with massive haemoptysis treated between January 1969 and December 1980 (group 1) were retrospectively reviewed and those prospectively treated between January 1981 and August 1999 ...

  14. Topologically massive gravity and Ricci-Cotton flow

    Energy Technology Data Exchange (ETDEWEB)

    Lashkari, Nima; Maloney, Alexander, E-mail: lashkari@physics.mcgill.ca, E-mail: maloney@physics.mcgill.ca [McGill Physics Department, 3600 rue University, Montreal, QC H3A 2T8 (Canada)

    2011-05-21

    We consider topologically massive gravity (TMG), which is three-dimensional general relativity with a cosmological constant and a gravitational Chern-Simons term. When the cosmological constant is negative the theory has two potential vacuum solutions: anti-de Sitter space and warped anti-de Sitter space. The theory also contains a massive graviton state which renders these solutions unstable for certain values of the parameters and boundary conditions. We study the decay of these solutions due to the condensation of the massive graviton mode using Ricci-Cotton flow, which is the appropriate generalization of Ricci flow to TMG. When the Chern-Simons coupling is small the AdS solution flows to warped AdS by the condensation of the massive graviton mode. When the coupling is large the situation is reversed, and warped AdS flows to AdS. Minisuperspace models are constructed where these flows are studied explicitly.

  15. Topologically massive gravity and Ricci-Cotton flow

    International Nuclear Information System (INIS)

    Lashkari, Nima; Maloney, Alexander

    2011-01-01

    We consider topologically massive gravity (TMG), which is three-dimensional general relativity with a cosmological constant and a gravitational Chern-Simons term. When the cosmological constant is negative the theory has two potential vacuum solutions: anti-de Sitter space and warped anti-de Sitter space. The theory also contains a massive graviton state which renders these solutions unstable for certain values of the parameters and boundary conditions. We study the decay of these solutions due to the condensation of the massive graviton mode using Ricci-Cotton flow, which is the appropriate generalization of Ricci flow to TMG. When the Chern-Simons coupling is small the AdS solution flows to warped AdS by the condensation of the massive graviton mode. When the coupling is large the situation is reversed, and warped AdS flows to AdS. Minisuperspace models are constructed where these flows are studied explicitly.

  16. Central Hypothyroidism in Miniature Schnauzers

    NARCIS (Netherlands)

    Voorbij, Annemarie M W Y; Leegwater, Peter A J; Buijtels, Jenny J C W M; Daminet, Sylvie; Kooistra, Hans S

    2016-01-01

    BACKGROUND: Primary hypothyroidism is a common endocrinopathy in dogs. In contrast, central hypothyroidism is rare in this species. OBJECTIVES: The objective of this article is to describe the occurrence and clinical presentation of central hypothyroidism in Miniature Schnauzers. Additionally, the

  17. Permutations of massive vacua

    Energy Technology Data Exchange (ETDEWEB)

    Bourget, Antoine [Department of Physics, Universidad de Oviedo, Avenida Calvo Sotelo 18, 33007 Oviedo (Spain); Troost, Jan [Laboratoire de Physique Théorique de l’É cole Normale Supérieure, CNRS,PSL Research University, Sorbonne Universités, 75005 Paris (France)

    2017-05-09

    We discuss the permutation group G of massive vacua of four-dimensional gauge theories with N=1 supersymmetry that arises upon tracing loops in the space of couplings. We concentrate on superconformal N=4 and N=2 theories with N=1 supersymmetry preserving mass deformations. The permutation group G of massive vacua is the Galois group of characteristic polynomials for the vacuum expectation values of chiral observables. We provide various techniques to effectively compute characteristic polynomials in given theories, and we deduce the existence of varying symmetry breaking patterns of the duality group depending on the gauge algebra and matter content of the theory. Our examples give rise to interesting field extensions of spaces of modular forms.

  18. Massive stars in galaxies

    International Nuclear Information System (INIS)

    Humphreys, R.M.

    1987-01-01

    The relationship between the morphologic type of a galaxy and the evolution of its massive stars is explored, reviewing observational results for nearby galaxies. The data are presented in diagrams, and it is found that the massive-star populations of most Sc spiral galaxies and irregular galaxies are similar, while those of Sb spirals such as M 31 and M 81 may be affected by morphology (via differences in the initial mass function or star-formation rate). Consideration is also given to the stability-related upper luminosity limit in the H-R diagram of hypergiant stars (attributed to radiation pressure in hot stars and turbulence in cool stars) and the goals of future observation campaigns. 88 references

  19. EVALUATION OF AN ENTERPRISE - CENTRAL OBJECT FOR ROMANIAN SPECIALISTS FROM VARIOUS FIELDS OF ACTIVITY

    Directory of Open Access Journals (Sweden)

    ENEA CONSTANTIN

    2017-12-01

    Full Text Available An enterprise evaluation is a central object for Romanian specialists from various fields of activity, not only needed in privatization of commercial companies, but also in the process of transition to market economy. Thus, the problem of knowing the most accurate value a company is placed when a securities issue takes place, o sale of assets or when the reorganization process is triggered legal liquidation of an enterprise; in these situations it is necessary to establish the value of the firm not only in terms of the value of fixed assets and but also depending on the future capacity of the enterprise to generate profit. The case study refers to the evaluation of the Gorj Hotel in Targu Jiu, where the financial situations were relevant and underpinned by the correct evaluation of the SC Gorjul SA patrimony.

  20. Multi-wavelength study of young and massive galaxy clusters

    International Nuclear Information System (INIS)

    Lemonon, Ludovic

    1999-01-01

    Clusters of galaxies are the most massive objects gravitationally bound observed. They are the consequence of the evolution of most important perturbations in the cosmological microwave background. Their formation depends strongly of the cosmology, so they represent key objects to understand the Universe. The aim of this thesis is to study the processes of formation in clusters of galaxies well far away than previous studies clone, by high-resolution observations obtained by using most powerful telescope in each studied wavelength: X-ray, visible, infrared and radio. After data reductions of 12 clusters located at 0.1; z; 0.3, I was able to classified them in three categories: dynamically perturbed clusters, with substructures in their X-ray/optical image or velocity distribution of galaxies; cooling flows clusters, more relaxed than previous, with huge amount of gas cooling in their center; AGN contaminated, where the central dominant galaxy is an AGN which contaminate considerably the X-ray emission. I have obtained a measurement of the baryonic fraction of the Universe mass, and an estimation of the Universe matter density parameter at the mega-parsec scale, claiming for a low density universe. The ISOCAM data showed the effect of the ICM interactions on the star formation in cluster galaxies, and demonstrated that optical and mid-IR deduced star-formation are not basically compatible. They also showed how IR-emitting galaxies distribute in clusters, most noticeably how 15 um galaxies are located preferably on the edge of clusters. X-ray and radio data showed that clusters at z 0.25 could be find in several dynamical state, similarly with nearby ones, from relaxed to severely perturbed. All clusters present signs of past or present merging, in agreement with hierarchical structure formation scenario. This clusters database is an excellent starting point to study process of merging in clusters since they showed different aspect of this evolution. (author) [fr

  1. Nitrogen chronology of massive main sequence stars

    NARCIS (Netherlands)

    Köhler, K.; Borzyszkowski, M.; Brott, I.; Langer, N.; de Koter, A.

    2012-01-01

    Context. Rotational mixing in massive main sequence stars is predicted to monotonically increase their surface nitrogen abundance with time. Aims. We use this effect to design a method for constraining the age and the inclination angle of massive main sequence stars, given their observed luminosity,

  2. An over-massive black hole in the compact lenticular galaxy NGC 1277.

    Science.gov (United States)

    van den Bosch, Remco C E; Gebhardt, Karl; Gültekin, Kayhan; van de Ven, Glenn; van der Wel, Arjen; Walsh, Jonelle L

    2012-11-29

    Most massive galaxies have supermassive black holes at their centres, and the masses of the black holes are believed to correlate with properties of the host-galaxy bulge component. Several explanations have been proposed for the existence of these locally established empirical relationships, including the non-causal, statistical process of galaxy-galaxy merging, direct feedback between the black hole and its host galaxy, and galaxy-galaxy merging and the subsequent violent relaxation and dissipation. The empirical scaling relations are therefore important for distinguishing between various theoretical models of galaxy evolution, and they furthermore form the basis for all black-hole mass measurements at large distances. Observations have shown that the mass of the black hole is typically 0.1 per cent of the mass of the stellar bulge of the galaxy. Until now, the galaxy with the largest known fraction of its mass in its central black hole (11 per cent) was the small galaxy NGC 4486B. Here we report observations of the stellar kinematics of NGC 1277, which is a compact, lenticular galaxy with a mass of 1.2 × 10(11) solar masses. From the data, we determine that the mass of the central black hole is 1.7 × 10(10) solar masses, or 59 per cent of its bulge mass. We also show observations of five other compact galaxies that have properties similar to NGC 1277 and therefore may also contain over-massive black holes. It is not yet known if these galaxies represent a tail of a distribution, or if disk-dominated galaxies fail to follow the usual black-hole mass scaling relations.

  3. Using massive digital libraries a LITA guide

    CERN Document Server

    Weiss, Andrew

    2014-01-01

    Some have viewed the ascendance of the digital library as some kind of existential apocalypse, nothing less than the beginning of the end for the traditional library. But Weiss, recognizing the concept of the library as a ""big idea"" that has been implemented in many ways over thousands of years, is not so gloomy. In this thought-provoking and unabashedly optimistic book, he explores how massive digital libraries are already adapting to society's needs, and looks ahead to the massive digital libraries of tomorrow, coveringThe author's criteria for defining massive digital librariesA history o

  4. Two-dimensional thermofield bosonization II: Massive fermions

    International Nuclear Information System (INIS)

    Amaral, R.L.P.G.; Belvedere, L.V.; Rothe, K.D.

    2008-01-01

    We consider the perturbative computation of the N-point function of chiral densities of massive free fermions at finite temperature within the thermofield dynamics approach. The infinite series in the mass parameter for the N-point functions are computed in the fermionic formulation and compared with the corresponding perturbative series in the interaction parameter in the bosonized thermofield formulation. Thereby we establish in thermofield dynamics the formal equivalence of the massive free fermion theory with the sine-Gordon thermofield model for a particular value of the sine-Gordon parameter. We extend the thermofield bosonization to include the massive Thirring model

  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. Limiting Accretion onto Massive Stars by Fragmentation-Induced Starvation

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Thomas; /ZAH, Heidelberg; Klessen, Ralf S.; /ZAH, Heidelberg /KIPAC, Menlo Park; Mac Low, Mordecai-Mark; /Amer. Museum Natural Hist.; Banerjee, Robi; /ZAH, Heidelberg

    2010-08-25

    Massive stars influence their surroundings through radiation, winds, and supernova explosions far out of proportion to their small numbers. However, the physical processes that initiate and govern the birth of massive stars remain poorly understood. Two widely discussed models are monolithic collapse of molecular cloud cores and competitive accretion. To learn more about massive star formation, we perform simulations of the collapse of rotating, massive, cloud cores including radiative heating by both non-ionizing and ionizing radiation using the FLASH adaptive mesh refinement code. These simulations show fragmentation from gravitational instability in the enormously dense accretion flows required to build up massive stars. Secondary stars form rapidly in these flows and accrete mass that would have otherwise been consumed by the massive star in the center, in a process that we term fragmentation-induced starvation. This explains why massive stars are usually found as members of high-order stellar systems that themselves belong to large clusters containing stars of all masses. The radiative heating does not prevent fragmentation, but does lead to a higher Jeans mass, resulting in fewer and more massive stars than would form without the heating. This mechanism reproduces the observed relation between the total stellar mass in the cluster and the mass of the largest star. It predicts strong clumping and filamentary structure in the center of collapsing cores, as has recently been observed. We speculate that a similar mechanism will act during primordial star formation.

  7. Management of massive hemoptysis in pulmonary tuberculosis and bronchiectasis by bronchial arterial embolization

    International Nuclear Information System (INIS)

    Fan Yong; Yin Baoquan; Han Bingsen; He Nengshu

    2005-01-01

    Objective: To probe into the angiographic signs and the variations of bronchial arteries for pulmonary tuberculosis or bronchiectasis with massive hemoptysis. Methods: 25 patients with pulmonary tuberculosis and 15 patients suffered from bronchiectasis accompanied by massive hemoptysis were undertaken bronchial arterial embolization (BAE). All patients were embolized with gelfoam including 32 with spring coils in addition. Results: 63 arteries demonstrated angiographic signs of hemoptysis in 40 patients. The immediate stanching rate was 92.5%(37/40). The bronchopulmonary shunt formation sign shown by angiograph was the major feature of tuberculosis (P=0.0528) and the enlarged tortuous arteries in bronchiectasis were more to be demonstrated than in tuberculosis (P<0.05). Conclusions: The BAE for patients with tuberculosis ought to be performed in the smaller arteries. BAE for patients with bronchiectasis should to be taken in the trunk of arteries. (authors)

  8. Hunting for a massive neutrino

    CERN Document Server

    AUTHOR|(CDS)2108802

    1997-01-01

    A great effort is devoted by many groups of physicists all over the world to give an answer to the following question: Is the neutrino massive ? This question has profound implications with particle physics, astrophysics and cosmology, in relation to the so-called Dark Matter puzzle. The neutrino oscillation process, in particular, can only occur if the neutrino is massive. An overview of the neutrino mass measurements, of the oscillation formalism and experiments will be given, also in connection with the present experimental programme at CERN with the two experiments CHORUS and NOMAD.

  9. THE FRAGMENTATION OF MAGNETIZED, MASSIVE STAR-FORMING CORES WITH RADIATIVE FEEDBACK

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Andrew T.; McKee, Christopher F. [Department of Physics, University of California, Berkeley, Berkeley, CA 94720 (United States); Cunningham, Andrew J. [Lawrence Livermore National Laboratory, P.O. Box 808, L-23, Livermore, CA 94550 (United States); Klein, Richard I. [Department of Astronomy, University of California, Berkeley, Berkeley, CA 94720 (United States); Krumholz, Mark R., E-mail: atmyers@berkeley.edu [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2013-04-01

    We present a set of three-dimensional, radiation-magnetohydrodynamic calculations of the gravitational collapse of massive (300 M{sub Sun }), star-forming molecular cloud cores. We show that the combined effects of magnetic fields and radiative feedback strongly suppress core fragmentation, leading to the production of single-star systems rather than small clusters. We find that the two processes are efficient at suppressing fragmentation in different regimes, with the feedback most effective in the dense, central region and the magnetic field most effective in more diffuse, outer regions. Thus, the combination of the two is much more effective at suppressing fragmentation than either one considered in isolation. Our work suggests that typical massive cores, which have mass-to-flux ratios of about 2 relative to critical, likely form a single-star system, but that cores with weaker fields may form a small star cluster. This result helps us understand why the observed relationship between the core mass function and the stellar initial mass function holds even for {approx}100 M{sub Sun} cores with many thermal Jeans masses of material. We also demonstrate that a {approx}40 AU Keplerian disk is able to form in our simulations, despite the braking effect caused by the strong magnetic field.

  10. On the singularities of massive superstring amplitudes

    NARCIS (Netherlands)

    Foda, O.

    1987-01-01

    Superstring one-loop amplitudes with massive external states are shown to be in general ill-defined due to internal on-shell propagators. However, we argue that since any massive string state (in the uncompactified theory) has a finite lifetime to decay into massless particles, such amplitudes are

  11. Delayed Presentation of an Extracranial Internal Carotid Artery Pseudoaneurysm and Massive Epistaxis Secondary to a Nasal Foreign Body: Case Report and Review of the Literature.

    Science.gov (United States)

    Katsevman, Gennadiy A; Braca, John A; Welch, Kevin C; Ashley, William W

    2016-08-01

    Epistaxis is a very common medical condition and can often be controlled with conservative measures. Rarely, uncontrolled and life-threatening epistaxis can occur. We present the case of a 58-year-old man who developed delayed, massive epistaxis caused by an extracranial left internal carotid artery pseudoaneurysm caused by an intranasal foreign object without apparent recent trauma. The patient was successfully treated with endovascular stenting of the affected vessel segment. Massive epistaxis is a potentially lethal condition. Although the source uncommonly originates from the internal carotid artery, pseudoaneurysm rupture needs to be considered on the differential diagnosis in selected patients. This case illustrates the need for vigilance for the presence of foreign objects and/or vessel injuries in the setting of acute, massive epistaxis. Additionally, we describe treatment options and review the literature. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Black holes in massive gravity as heat engines

    Science.gov (United States)

    Hendi, S. H.; Eslam Panah, B.; Panahiyan, S.; Liu, H.; Meng, X.-H.

    2018-06-01

    The paper at hand studies the heat engine provided by black holes in the presence of massive gravity. The main motivation is to investigate the effects of massive gravity on different properties of the heat engine. It will be shown that massive gravity parameters modify the efficiency of engine on a significant level. Furthermore, it will be pointed out that it is possible to have a heat engine for non-spherical black holes in massive gravity, and therefore, we will study the effects of horizon topology on the properties of heat engine. Surprisingly, it will be shown that the highest efficiency for the heat engine belongs to black holes with the hyperbolic horizon, while the lowest one belongs to the spherical black holes.

  13. The VLT-FLAMES survey of massive stars

    NARCIS (Netherlands)

    Evans, C.; Langer, N.; Brott, I.; Hunter, I.; Smartt, S.J.; Lennon, D.J.

    2008-01-01

    The VLT-FLAMES Survey of Massive Stars was an ESO Large Programme to understand rotational mixing and stellar mass loss in different metallicity environments, in order to better constrain massive star evolution. We gathered high-quality spectra of over 800 stars in the Galaxy and in the Magellanic

  14. Massive cerebellar infarction: a neurosurgical approach

    Directory of Open Access Journals (Sweden)

    Salazar Luis Rafael Moscote

    2015-12-01

    Full Text Available Cerebellar infarction is a challenge for the neurosurgeon. The rapid recognition will crucial to avoid devastating consequences. The massive cerebellar infarction has pseudotumoral behavior, should affect at least one third of the volume of the cerebellum. The irrigation of the cerebellum presents anatomical diversity, favoring the appearance of atypical infarcts. The neurosurgical management is critical for massive cerebellar infarction. We present a review of the literature.

  15. A plausible energy source and structure for quasi-stellar objects

    Science.gov (United States)

    Daltabuit, E.; Cox, D.

    1972-01-01

    If a collision of two large, massive, fast gas clouds occurs, their kinetic energy is converted to radiation in a pair of shock fronts at their interface. The resulting structure is described, and the relevance of this as a radiation source for quasi-stellar objects is considered.

  16. Dusty supernovae running the thermodynamics of the matter reinserted within young and massive super stellar clusters

    Energy Technology Data Exchange (ETDEWEB)

    Tenorio-Tagle, Guillermo; Silich, Sergiy; Martínez-González, Sergio [Instituto Nacional de Astrofísica Óptica y Electrónica, AP 51, 72000 Puebla (Mexico); Muñoz-Tuñón, Casiana [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Palouš, Jan; Wünsch, Richard, E-mail: gtt@inaoep.mx, E-mail: cmt@ll.iac.es [Astronomical Institute, Academy of Sciences of the Czech Republic, Boční II 1401, 141 31 Prague (Czech Republic)

    2013-12-01

    Following the observational and theoretical evidence that points at core-collapse supernovae (SNe) as major producers of dust, here we calculate the hydrodynamics of the matter reinserted within young and massive super stellar clusters under the assumption of gas and dust radiative cooling. The large SN rate expected in massive clusters allows for a continuous replenishment of dust immersed in the high temperature thermalized reinserted matter and warrants a stationary presence of dust within the cluster volume during the type II SN era. We first show that such a balance determines the range of the dust-to-gas-mass ratio, and thus the dust cooling law. We then search for the critical line that separates stationary cluster winds from the bimodal cases in the cluster mechanical luminosity (or cluster mass) versus cluster size parameter space. In the latter, strong radiative cooling reduces considerably the cluster wind mechanical energy output and affects particularly the cluster central regions, leading to frequent thermal instabilities that diminish the pressure and inhibit the exit of the reinserted matter. Instead, matter accumulates there and is expected to eventually lead to gravitational instabilities and to further stellar formation with the matter reinserted by former massive stars. The main outcome of the calculations is that the critical line is almost two orders of magnitude or more, depending on the assumed value of V {sub A∞}, lower than when only gas radiative cooling is applied. And thus, many massive clusters are predicted to enter the bimodal regime.

  17. On massive gravitons in 2+1 dimensions

    NARCIS (Netherlands)

    Bergshoeff, Eric; Hohm, Olaf; Townsend, Paul; Lazkoz, R; Vera, R

    2010-01-01

    The Fierz-Pauli (FP) free field theory for massive spin-2 particles can be extended, in a spacetime of (1+2) dimensions (3D), to a generally covariant parity-preserving interacting field theory, in at least two ways. One is "new massive gravity" (NMG), with an action that involves curvature-squared

  18. Asymptotically anti-de Sitter spacetimes in topologically massive gravity

    International Nuclear Information System (INIS)

    Henneaux, Marc; Martinez, Cristian; Troncoso, Ricardo

    2009-01-01

    We consider asymptotically anti-de Sitter spacetimes in three-dimensional topologically massive gravity with a negative cosmological constant, for all values of the mass parameter μ (μ≠0). We provide consistent boundary conditions that accommodate the recent solutions considered in the literature, which may have a slower falloff than the one relevant for general relativity. These conditions are such that the asymptotic symmetry is in all cases the conformal group, in the sense that they are invariant under asymptotic conformal transformations and that the corresponding Virasoro generators are finite. It is found that, at the chiral point |μl|=1 (where l is the anti-de Sitter radius), allowing for logarithmic terms (absent for general relativity) in the asymptotic behavior of the metric makes both sets of Virasoro generators nonzero even though one of the central charges vanishes.

  19. Holographic heat engine within the framework of massive gravity

    Science.gov (United States)

    Mo, Jie-Xiong; Li, Gu-Qiang

    2018-05-01

    Heat engine models are constructed within the framework of massive gravity in this paper. For the four-dimensional charged black holes in massive gravity, it is shown that the existence of graviton mass improves the heat engine efficiency significantly. The situation is more complicated for the five-dimensional neutral black holes since the constant which corresponds to the third massive potential also contributes to the efficiency. It is also shown that the existence of graviton mass can improve the heat engine efficiency. Moreover, we probe how the massive gravity influences the behavior of the heat engine efficiency approaching the Carnot efficiency.

  20. Detection of water masers toward young stellar objects in the Large Magellanic Cloud

    International Nuclear Information System (INIS)

    Johanson, A. K.; Migenes, V.; Breen, S. L.

    2014-01-01

    We present results from a search for water maser emission toward N4A, N190, and N206, three regions of massive star formation in the Large Magellanic Cloud (LMC). Four water masers were detected; two toward N4A, and two toward N190. In the latter region, no previously known maser emission has been reported. Future studies of maser proper motion to determine the galactic dynamics of the LMC will benefit from the independent data points the new masers in N190 provide. Two of these masers are associated with previously identified massive young stellar objects (YSOs), which strongly supports the authenticity of the classification. We argue that the other two masers identify previously unknown YSOs. No masers were detected toward N206, but it does host a newly discovered 22 GHz continuum source, also associated with a massive YSO. We suggest that future surveys for water maser emission in the LMC be targeted toward the more luminous, massive YSOs.

  1. High molecular gas fractions in normal massive star-forming galaxies in the young Universe.

    Science.gov (United States)

    Tacconi, L J; Genzel, R; Neri, R; Cox, P; Cooper, M C; Shapiro, K; Bolatto, A; Bouché, N; Bournaud, F; Burkert, A; Combes, F; Comerford, J; Davis, M; Schreiber, N M Förster; Garcia-Burillo, S; Gracia-Carpio, J; Lutz, D; Naab, T; Omont, A; Shapley, A; Sternberg, A; Weiner, B

    2010-02-11

    Stars form from cold molecular interstellar gas. As this is relatively rare in the local Universe, galaxies like the Milky Way form only a few new stars per year. Typical massive galaxies in the distant Universe formed stars an order of magnitude more rapidly. Unless star formation was significantly more efficient, this difference suggests that young galaxies were much more molecular-gas rich. Molecular gas observations in the distant Universe have so far largely been restricted to very luminous, rare objects, including mergers and quasars, and accordingly we do not yet have a clear idea about the gas content of more normal (albeit massive) galaxies. Here we report the results of a survey of molecular gas in samples of typical massive-star-forming galaxies at mean redshifts of about 1.2 and 2.3, when the Universe was respectively 40% and 24% of its current age. Our measurements reveal that distant star forming galaxies were indeed gas rich, and that the star formation efficiency is not strongly dependent on cosmic epoch. The average fraction of cold gas relative to total galaxy baryonic mass at z = 2.3 and z = 1.2 is respectively about 44% and 34%, three to ten times higher than in today's massive spiral galaxies. The slow decrease between z approximately 2 and z approximately 1 probably requires a mechanism of semi-continuous replenishment of fresh gas to the young galaxies.

  2. Formation of Massive Molecular Cloud Cores by Cloud-cloud Collision

    OpenAIRE

    Inoue, Tsuyoshi; Fukui, Yasuo

    2013-01-01

    Recent observations of molecular clouds around rich massive star clusters including NGC3603, Westerlund 2, and M20 revealed that the formation of massive stars could be triggered by a cloud-cloud collision. By using three-dimensional, isothermal, magnetohydrodynamics simulations with the effect of self-gravity, we demonstrate that massive, gravitationally unstable, molecular cloud cores are formed behind the strong shock waves induced by the cloud-cloud collision. We find that the massive mol...

  3. Massively Parallel Algorithms for Solution of Schrodinger Equation

    Science.gov (United States)

    Fijany, Amir; Barhen, Jacob; Toomerian, Nikzad

    1994-01-01

    In this paper massively parallel algorithms for solution of Schrodinger equation are developed. Our results clearly indicate that the Crank-Nicolson method, in addition to its excellent numerical properties, is also highly suitable for massively parallel computation.

  4. Critical N = (1, 1) general massive supergravity

    Science.gov (United States)

    Deger, Nihat Sadik; Moutsopoulos, George; Rosseel, Jan

    2018-04-01

    In this paper we study the supermultiplet structure of N = (1, 1) General Massive Supergravity at non-critical and critical points of its parameter space. To do this, we first linearize the theory around its maximally supersymmetric AdS3 vacuum and obtain the full linearized Lagrangian including fermionic terms. At generic values, linearized modes can be organized as two massless and 2 massive multiplets where supersymmetry relates them in the standard way. At critical points logarithmic modes appear and we find that in three of such points some of the supersymmetry transformations are non-invertible in logarithmic multiplets. However, in the fourth critical point, there is a massive logarithmic multiplet with invertible supersymmetry transformations.

  5. HOW TO FIND YOUNG MASSIVE CLUSTER PROGENITORS

    Energy Technology Data Exchange (ETDEWEB)

    Bressert, E.; Longmore, S.; Testi, L. [European Southern Observatory, Karl Schwarzschild Str. 2, D-85748 Garching bei Muenchen (Germany); Ginsburg, A.; Bally, J.; Battersby, C. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States)

    2012-10-20

    We propose that bound, young massive stellar clusters form from dense clouds that have escape speeds greater than the sound speed in photo-ionized gas. In these clumps, radiative feedback in the form of gas ionization is bottled up, enabling star formation to proceed to sufficiently high efficiency so that the resulting star cluster remains bound even after gas removal. We estimate the observable properties of the massive proto-clusters (MPCs) for existing Galactic plane surveys and suggest how they may be sought in recent and upcoming extragalactic observations. These surveys will potentially provide a significant sample of MPC candidates that will allow us to better understand extreme star-formation and massive cluster formation in the Local Universe.

  6. Massive type IIA supergravity and E10

    International Nuclear Information System (INIS)

    Henneaux, M.; Kleinschmidt, A.; Persson, D.; Jamsin, E.

    2009-01-01

    In this talk we investigate the symmetry under E 10 of Romans' massive type IIA supergravity. We show that the dynamics of a spinning particle in a non-linear sigma model on the coset space E 10 /K(E 10 ) reproduces the bosonic and fermionic dynamics of massive IIA supergravity, in the standard truncation. In particular, we identify Romans' mass with a generator of E 10 that is beyond the realm of the generators of E 10 considered in the eleven-dimensional analysis, but using the same, underformed sigma model. As a consequence, this work provides a dynamical unification of the massless and massive versions of type IIA supergravity inside E 10 . (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  7. Reappraising the concept of massive transfusion in trauma

    DEFF Research Database (Denmark)

    Stanworth, Simon J; Morris, Timothy P; Gaarder, Christine

    2010-01-01

    ABSTRACT : INTRODUCTION : The massive-transfusion concept was introduced to recognize the dilutional complications resulting from large volumes of packed red blood cells (PRBCs). Definitions of massive transfusion vary and lack supporting clinical evidence. Damage-control resuscitation regimens o...

  8. Massive stars and X-ray pulsars

    International Nuclear Information System (INIS)

    Henrichs, H.

    1982-01-01

    This thesis is a collection of 7 separate articles entitled: long term changes in ultraviolet lines in γ CAS, UV observations of γ CAS: intermittent mass-loss enhancement, episodic mass loss in γ CAS and in other early-type stars, spin-up and spin-down of accreting neutron stars, an excentric close binary model for the X Persei system, has a 97 minute periodicity in 4U 1700-37/HD 153919 really been discovered, and, mass loss and stellar wind in massive X-ray binaries. (Articles 1, 2, 5, 6 and 7 have been previously published). The first three articles are concerned with the irregular mass loss in massive stars. The fourth critically reviews thoughts since 1972 on the origin of the changes in periodicity shown by X-ray pulsars. The last articles indicate the relation between massive stars and X-ray pulsars. (C.F.)

  9. An effective theory of massive gauge bosons

    International Nuclear Information System (INIS)

    Doria, R.M.; Helayel Neto, J.A.

    1986-01-01

    The coupling of a group-valued massive scalar field to a gauge field through a symmetric rank-2 field strenght is studied. By considering energies very small compared with the mass of the scalar and invoking the decoupling theorem, one is left with a low-energy effective theory describing a dynamics of massive vector fields. (Author) [pt

  10. Massive gravity with mass term in three dimensions

    International Nuclear Information System (INIS)

    Nakasone, Masashi; Oda, Ichiro

    2009-01-01

    We analyze the effect of the Pauli-Fierz mass term on a recently established, new massive gravity theory in three space-time dimensions. We show that the Pauli-Fierz mass term makes the new massive gravity theory nonunitary. Moreover, although we add the gravitational Chern-Simons term to this model, the situation remains unchanged and the theory stays nonunitary despite that the structure of the graviton propagator is greatly changed. Thus, the Pauli-Fierz mass term is not allowed to coexist with mass-generating higher-derivative terms in the new massive gravity.

  11. Reappraising the concept of massive transfusion in trauma

    NARCIS (Netherlands)

    Stanworth, Simon J.; Morris, Timothy P.; Gaarder, Christine; Goslings, J. Carel; Maegele, Marc; Cohen, Mitchell J.; König, Thomas C.; Davenport, Ross A.; Pittet, Jean-Francois; Johansson, Pär I.; Allard, Shubha; Johnson, Tony; Brohi, Karim

    2010-01-01

    The massive-transfusion concept was introduced to recognize the dilutional complications resulting from large volumes of packed red blood cells (PRBCs). Definitions of massive transfusion vary and lack supporting clinical evidence. Damage-control resuscitation regimens of modern trauma care are

  12. Massive hybrid parallelism for fully implicit multiphysics

    International Nuclear Information System (INIS)

    Gaston, D. R.; Permann, C. J.; Andrs, D.; Peterson, J. W.

    2013-01-01

    As hardware advances continue to modify the supercomputing landscape, traditional scientific software development practices will become more outdated, ineffective, and inefficient. The process of rewriting/retooling existing software for new architectures is a Sisyphean task, and results in substantial hours of development time, effort, and money. Software libraries which provide an abstraction of the resources provided by such architectures are therefore essential if the computational engineering and science communities are to continue to flourish in this modern computing environment. The Multiphysics Object Oriented Simulation Environment (MOOSE) framework enables complex multiphysics analysis tools to be built rapidly by scientists, engineers, and domain specialists, while also allowing them to both take advantage of current HPC architectures, and efficiently prepare for future supercomputer designs. MOOSE employs a hybrid shared-memory and distributed-memory parallel model and provides a complete and consistent interface for creating multiphysics analysis tools. In this paper, a brief discussion of the mathematical algorithms underlying the framework and the internal object-oriented hybrid parallel design are given. Representative massively parallel results from several applications areas are presented, and a brief discussion of future areas of research for the framework are provided. (authors)

  13. Massive hybrid parallelism for fully implicit multiphysics

    Energy Technology Data Exchange (ETDEWEB)

    Gaston, D. R.; Permann, C. J.; Andrs, D.; Peterson, J. W. [Idaho National Laboratory, 2525 N. Fremont Ave., Idaho Falls, ID 83415 (United States)

    2013-07-01

    As hardware advances continue to modify the supercomputing landscape, traditional scientific software development practices will become more outdated, ineffective, and inefficient. The process of rewriting/retooling existing software for new architectures is a Sisyphean task, and results in substantial hours of development time, effort, and money. Software libraries which provide an abstraction of the resources provided by such architectures are therefore essential if the computational engineering and science communities are to continue to flourish in this modern computing environment. The Multiphysics Object Oriented Simulation Environment (MOOSE) framework enables complex multiphysics analysis tools to be built rapidly by scientists, engineers, and domain specialists, while also allowing them to both take advantage of current HPC architectures, and efficiently prepare for future supercomputer designs. MOOSE employs a hybrid shared-memory and distributed-memory parallel model and provides a complete and consistent interface for creating multiphysics analysis tools. In this paper, a brief discussion of the mathematical algorithms underlying the framework and the internal object-oriented hybrid parallel design are given. Representative massively parallel results from several applications areas are presented, and a brief discussion of future areas of research for the framework are provided. (authors)

  14. MASSIVE HYBRID PARALLELISM FOR FULLY IMPLICIT MULTIPHYSICS

    Energy Technology Data Exchange (ETDEWEB)

    Cody J. Permann; David Andrs; John W. Peterson; Derek R. Gaston

    2013-05-01

    As hardware advances continue to modify the supercomputing landscape, traditional scientific software development practices will become more outdated, ineffective, and inefficient. The process of rewriting/retooling existing software for new architectures is a Sisyphean task, and results in substantial hours of development time, effort, and money. Software libraries which provide an abstraction of the resources provided by such architectures are therefore essential if the computational engineering and science communities are to continue to flourish in this modern computing environment. The Multiphysics Object Oriented Simulation Environment (MOOSE) framework enables complex multiphysics analysis tools to be built rapidly by scientists, engineers, and domain specialists, while also allowing them to both take advantage of current HPC architectures, and efficiently prepare for future supercomputer designs. MOOSE employs a hybrid shared-memory and distributed-memory parallel model and provides a complete and consistent interface for creating multiphysics analysis tools. In this paper, a brief discussion of the mathematical algorithms underlying the framework and the internal object-oriented hybrid parallel design are given. Representative massively parallel results from several applications areas are presented, and a brief discussion of future areas of research for the framework are provided.

  15. Massive-Star Magnetospheres: Now in 3-D!

    Science.gov (United States)

    Townsend, Richard

    Magnetic fields are unexpected in massive stars, due to the absence of a dynamo convection zone beneath their surface layers. Nevertheless, kilogauss-strength, ordered fields were detected in a small subset of these stars over three decades ago, and the intervening years have witnessed the steady expansion of this subset. A distinctive feature of magnetic massive stars is that they harbor magnetospheres --- circumstellar environments where the magnetic field interacts strongly with the star's radiation-driven wind, confining it and channelling it into energetic shocks. A wide range of observational signatures are associated with these magnetospheres, in diagnostics ranging from X-rays all the way through to radio emission. Moreover, these magnetospheres can play an important role in massive-star evolution, by amplifying angular momentum loss in the wind. Recent progress in understanding massive-star magnetospheres has largely been driven by magnetohydrodynamical (MHD) simulations. However, these have been restricted to two- dimensional axisymmetric configurations, with three-dimensional configurations possible only in certain special cases. These restrictions are limiting further progress; we therefore propose to develop completely general three-dimensional models for the magnetospheres of massive stars, on the one hand to understand their observational properties and exploit them as plasma-physics laboratories, and on the other to gain a comprehensive understanding of how they influence the evolution of their host star. For weak- and intermediate-field stars, the models will be based on 3-D MHD simulations using a modified version of the ZEUS-MP code. For strong-field stars, we will extend our existing Rigid Field Hydrodynamics (RFHD) code to handle completely arbitrary field topologies. To explore a putative 'photoionization-moderated mass loss' mechanism for massive-star magnetospheres, we will also further develop a photoionization code we have recently

  16. Key Technologies in Massive MIMO

    Directory of Open Access Journals (Sweden)

    Hu Qiang

    2018-01-01

    Full Text Available The explosive growth of wireless data traffic in the future fifth generation mobile communication system (5G has led researchers to develop new disruptive technologies. As an extension of traditional MIMO technology, massive MIMO can greatly improve the throughput rate and energy efficiency, and can effectively improve the link reliability and data transmission rate, which is an important research direction of 5G wireless communication. Massive MIMO technology is nearly three years to get a new technology of rapid development and it through a lot of increasing the number of antenna communication, using very duplex communication mode, make the system spectrum efficiency to an unprecedented height.

  17. Super massive black hole in galactic nuclei with tidal disruption of stars

    International Nuclear Information System (INIS)

    Zhong, Shiyan; Berczik, Peter; Spurzem, Rainer

    2014-01-01

    Tidal disruption of stars by super massive central black holes from dense star clusters is modeled by high-accuracy direct N-body simulation. The time evolution of the stellar tidal disruption rate, the effect of tidal disruption on the stellar density profile, and, for the first time, the detailed origin of tidally disrupted stars are carefully examined and compared with classic papers in the field. Up to 128k particles are used in simulation to model the star cluster around a super massive black hole, and we use the particle number and the tidal radius of the black hole as free parameters for a scaling analysis. The transition from full to empty loss-cone is analyzed in our data, and the tidal disruption rate scales with the particle number, N, in the expected way for both cases. For the first time in numerical simulations (under certain conditions) we can support the concept of a critical radius of Frank and Rees, which claims that most stars are tidally accreted on highly eccentric orbits originating from regions far outside the tidal radius. Due to the consumption of stars moving on radial orbits, a velocity anisotropy is found inside the cluster. Finally we estimate the real galactic center based on our simulation results and the scaling analysis.

  18. Super Massive Black Hole in Galactic Nuclei with Tidal Disruption of Stars

    Science.gov (United States)

    Zhong, Shiyan; Berczik, Peter; Spurzem, Rainer

    2014-09-01

    Tidal disruption of stars by super massive central black holes from dense star clusters is modeled by high-accuracy direct N-body simulation. The time evolution of the stellar tidal disruption rate, the effect of tidal disruption on the stellar density profile, and, for the first time, the detailed origin of tidally disrupted stars are carefully examined and compared with classic papers in the field. Up to 128k particles are used in simulation to model the star cluster around a super massive black hole, and we use the particle number and the tidal radius of the black hole as free parameters for a scaling analysis. The transition from full to empty loss-cone is analyzed in our data, and the tidal disruption rate scales with the particle number, N, in the expected way for both cases. For the first time in numerical simulations (under certain conditions) we can support the concept of a critical radius of Frank & Rees, which claims that most stars are tidally accreted on highly eccentric orbits originating from regions far outside the tidal radius. Due to the consumption of stars moving on radial orbits, a velocity anisotropy is found inside the cluster. Finally we estimate the real galactic center based on our simulation results and the scaling analysis.

  19. Complicated Massive Choledochal Cyst: A Case Report | Okoromah ...

    African Journals Online (AJOL)

    Choledochal cysts are rare congenital anomalies resulting from congenital dilatations of the common bile duct (CBD) and usually they present during infancy with cholestatic jaundice. This report is on a massive-sized choledochal cyst associated with massive abdominal distention, respiratory embarrassment, postprandial ...

  20. Extensive tumor reconstruction with massive allograft

    International Nuclear Information System (INIS)

    Zulmi Wan

    1999-01-01

    Massive deep-frozen bone allografts were implanted in four patients after wide tumor resection. Two cases were solitary proximal femur metastases, secondary to Thyroid cancer and breast cancer respectively; while the other two cases were primary in nature i.e. Chondrosarcoma proximal humerus and Osteosarcoma proximal femur. All were treated with a cemented alloprosthesis except in the upper limb where shoulder fusion was performed. Augmentation of these techniques were done with a segment 1 free vascularised fibular composite graft to the proximal femur of breast secondaries and proximal humerus Chondrosarcoma. Coverage of the wound of the latter was also contributed by lattisimus dorsi flap. The present investigations demonstrated the massive bone allografts were intimately anchored by host bone and there had been no evidence of aseptic loosening at the graft-cement interface. This study showed that with good effective tumor control, reconstructive surgery with massive allografts represented a good alternative to prosthetic implants in tumors of the limbs. No infection was seen in all four cases

  1. Stellar Feedback in Massive Star-Forming Regions

    Science.gov (United States)

    Baldwin, Jack; Pellegrini, Eric; Ferland, Gary; Murray, Norm; Hanson, Margaret

    2008-02-01

    Star formation rates and chemical evolution are controlled in part by the interaction of stellar radiation and winds with the remnant molecular gas from which the stars have formed. We are carrying out a detailed, panchromatic study in the two nearest giant star-forming regions to nail down the physics that produces the 10-20 parsec bubbles seen to surround young massive clusters in the Milky Way. This will determine if and how the clusters disrupt their natal giant molecular clouds (GMCs). Here we request 4 nights on the Blanco telescope to obtain dense grids of optical long-slit spectra criss-crossing each nebula. These will cover the [S II] doublet (to measure N_e) and also [O III], H(beta), [O I], H(alpha) and [N II] to measure the ionization mechanism and ionization parameter, at ~3000 different spots in each nebula. From this we can determine a number of dynamically important quantities, such as the gas density and temperature, hence pressure in and around these bubbles. These quantities can be compared to the dynamical (gravitationally induced) pressure, and the radiation pressure. All can be employed in dynamical models for the evolution of a GMC under the influence of an embedded massive star cluster. This research will elucidate the detailed workings of the star-forming regions which dominate the star formation rate in the Milky Way, and also will steadily improve our calibration and understanding of more distant, less well-resolved objects such as ULIRGS, Lyman break, and submillimeter galaxies.

  2. From Lorentz-Chern-Simons to Massive Gravity in 2+1 dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Pino, Simón del [Instituto de Física, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso,Av. Universidad 330, Curauma, Valparaíso (Chile); Giribet, Gaston [Physique Théorique et Mathématique, Université Libre de Bruxelles andInternational Solvay Institutes,Campus Plaine C.P. 231, Bruxelles, B-1050 (Belgium); Departamento de Física, Universidad de Buenos Aires and IFIBA-CONICET,Ciudad Universitaria, Pabellón I, Buenos Aires, 1428 (Argentina); Instituto de Física, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso,Av. Universidad 330, Curauma, Valparaíso (Chile); Toloza, Adolfo [Instituto de Física, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso,Av. Universidad 330, Curauma, Valparaíso (Chile); Centro de Estudios Científicos CECs,Arturo Prat 514, Valdivia (Chile); Zanelli, Jorge [Centro de Estudios Científicos CECs,Arturo Prat 514, Valdivia (Chile)

    2015-06-17

    We propose a generalization of Chiral Gravity, which follows from considering a Chern-Simons action for the spin connection with anti-symmetric contorsion. The theory corresponds to Topologically Massive Gravity at the chiral point non-minimally coupled to an additional scalar mode that gathers the torsion degree of freedom. In this setup, the effective cosmological constant (the inverse of the curvature radius of maximally symmetric solutions) is either negative or zero, and it enters as an integration constant associated to the value of the contorsion at infinity. We explain how this is not in conflict with the Zamolodchikov’s c-theorem holding in the dual boundary theory. In fact, we conjecture that the theory formulated about three-dimensional Anti-de Sitter space is dual to a two-dimensional conformal field theory whose right- and left-moving central charges are given by c{sub R}=24k and c{sub L}=0, respectively, being k the level of the Chern-Simons action. We study the classical theory both at the linear and non-linear level. In particular, we show how Chiral Gravity is included as a special sector. In addition, the theory has other sectors, which we explore; we exhibit analytic exact solutions that are not solutions of Topologically Massive Gravity (and, consequently, neither of General Relativity) and still satisfy Brown-Henneaux asymptotically AdS{sub 3} boundary conditions.

  3. The multi-messenger approach to particle acceleration by massive stars: a science case for optical, radio and X-ray observatories

    Science.gov (United States)

    De Becker, Michaël

    2018-04-01

    Massive stars are extreme stellar objects whose properties allow for the study of some interesting physical processes, including particle acceleration up to relativistic velocities. In particular, the collisions of massive star winds in binary systems lead notably to acceleration of electrons involved in synchrotron emission, hence their identification as non-thermal radio emitters. This has been demonstrated for about 40 objects so far. The relativistic electrons are also expected to produce non-thermal high-energy radiation through inverse Compton scattering. This class of objects permits thus to investigate non-thermal physics through observations in the radio and high energy spectral domains. However, the binary nature of these sources introduces some stringent requirements to adequately interpret their behavior and model non-thermal processes. In particular, these objects are well-established variable stellar sources on the orbital time-scale. The stellar and orbital parameters need to be determined, and this is notably achieved through studies in the optical domain. The combination of observations in the visible domain (including e.g. 3.6-m DOT) with radio measurements using notably GMRT and X-ray observations constitutes thus a promising strategy to investigate particle-accelerating colliding-wind binaries in the forthcoming decade.

  4. Clinical application of bilateral uterine arterial chemoembolization in the treatment of massive hemorrhage due to cesarean scar pregnancy

    International Nuclear Information System (INIS)

    Wan Jun; Gu Weijin; Wang Haiyun; Ye Lei; Wang Wei; Zhang Lei; Ji Lihua

    2009-01-01

    Objective: To investigate the clinical application of bilateral uterine arterial chemoembolization in treating massive hemorrhage due to uterine scar pregnancy after cesarean section. Methods: Sixteen patients with massive hemorrhage due to cesarean scar pregnancy were enrolled in the study, the mean blood loss was (2 200 ± 1 400) ml. With Seldinger technique, abdominal angiography by using a pig-tail catheter was carried out. When bilateral uterine arterial bleeding was confirmed, selective or super-selective catheterization was employed and bilateral uterine arterial chemoembolization with infusion of 5-Fu or methotrexate (MTX) together with gelatin sponge via the catheters was conducted. The clinical results were observed. Results: The technical success was achieved in all 16 patients. No recurrent bleeding occurred during a follow-up of 3-6 months. Conclusion: The emergency bilateral uterine arterial chemoembolization is a safe and effective treatment for massive hemorrhage due to cesarean scar pregnancy with no serious complications, therefore, this technique is worth being used in clinical practice. (authors)

  5. A Massively Parallel Face Recognition System

    Directory of Open Access Journals (Sweden)

    Lahdenoja Olli

    2007-01-01

    Full Text Available We present methods for processing the LBPs (local binary patterns with a massively parallel hardware, especially with CNN-UM (cellular nonlinear network-universal machine. In particular, we present a framework for implementing a massively parallel face recognition system, including a dedicated highly accurate algorithm suitable for various types of platforms (e.g., CNN-UM and digital FPGA. We study in detail a dedicated mixed-mode implementation of the algorithm and estimate its implementation cost in the view of its performance and accuracy restrictions.

  6. A Massively Parallel Face Recognition System

    Directory of Open Access Journals (Sweden)

    Ari Paasio

    2006-12-01

    Full Text Available We present methods for processing the LBPs (local binary patterns with a massively parallel hardware, especially with CNN-UM (cellular nonlinear network-universal machine. In particular, we present a framework for implementing a massively parallel face recognition system, including a dedicated highly accurate algorithm suitable for various types of platforms (e.g., CNN-UM and digital FPGA. We study in detail a dedicated mixed-mode implementation of the algorithm and estimate its implementation cost in the view of its performance and accuracy restrictions.

  7. EVIDENCE FOR DELAYED MASSIVE STAR FORMATION IN THE M17 PROTO-OB ASSOCIATION

    International Nuclear Information System (INIS)

    Povich, Matthew S.; Whitney, Barbara A.

    2010-01-01

    Through analysis of archival images and photometry from the Spitzer GLIMPSE and MIPSGAL surveys combined with Two Micron All Sky Survey and MSX data, we have identified 488 candidate young stellar objects (YSOs) in the giant molecular cloud M17 SWex, which extends ∼50 pc southwest from the prominent Galactic H II region M17. Our sample includes >200 YSOs with masses >3 M sun that will become B-type stars on the main sequence. Extrapolating over the stellar initial mass function (IMF), we find that M17 SWex contains >1.3 x 10 4 young stars, representing a proto-OB association. The YSO mass function is significantly steeper than the Salpeter IMF, and early O stars are conspicuously absent from M17 SWex. Assuming M17 SWex will form an OB association with a Salpeter IMF, these results reveal the combined effects of (1) more rapid circumstellar disk evolution in more massive YSOs and (2) delayed onset of massive star formation.

  8. Primordial inhomogeneities from massive defects during inflation

    Energy Technology Data Exchange (ETDEWEB)

    Firouzjahi, Hassan; Karami, Asieh; Rostami, Tahereh, E-mail: firouz@ipm.ir, E-mail: karami@ipm.ir, E-mail: t.rostami@ipm.ir [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

    2016-10-01

    We consider the imprints of local massive defects, such as a black hole or a massive monopole, during inflation. The massive defect breaks the background homogeneity. We consider the limit that the physical Schwarzschild radius of the defect is much smaller than the inflationary Hubble radius so a perturbative analysis is allowed. The inhomogeneities induced in scalar and gravitational wave power spectrum are calculated. We obtain the amplitudes of dipole, quadrupole and octupole anisotropies in curvature perturbation power spectrum and identify the relative configuration of the defect to CMB sphere in which large observable dipole asymmetry can be generated. We observe a curious reflection symmetry in which the configuration where the defect is inside the CMB comoving sphere has the same inhomogeneous variance as its mirror configuration where the defect is outside the CMB sphere.

  9. The Galactic Distribution of Massive Star Formation from the Red MSX Source Survey

    Science.gov (United States)

    Figura, Charles C.; Urquhart, J. S.

    2013-01-01

    Massive stars inject enormous amounts of energy into their environments in the form of UV radiation and molecular outflows, creating HII regions and enriching local chemistry. These effects provide feedback mechanisms that aid in regulating star formation in the region, and may trigger the formation of subsequent generations of stars. Understanding the mechanics of massive star formation presents an important key to understanding this process and its role in shaping the dynamics of galactic structure. The Red MSX Source (RMS) survey is a multi-wavelength investigation of ~1200 massive young stellar objects (MYSO) and ultra-compact HII (UCHII) regions identified from a sample of colour-selected sources from the Midcourse Space Experiment (MSX) point source catalog and Two Micron All Sky Survey. We present a study of over 900 MYSO and UCHII regions investigated by the RMS survey. We review the methods used to determine distances, and investigate the radial galactocentric distribution of these sources in context with the observed structure of the galaxy. The distribution of MYSO and UCHII regions is found to be spatially correlated with the spiral arms and galactic bar. We examine the radial distribution of MYSOs and UCHII regions and find variations in the star formation rate between the inner and outer Galaxy and discuss the implications for star formation throughout the galactic disc.

  10. Reduction mammoplasty as a treatment for symptomatic central venous stenosis

    Directory of Open Access Journals (Sweden)

    Denise Seok Fun Fok

    2018-03-01

    Full Text Available Central venous stenosis is a rare cause of unilateral breast edema occurring in hemodialysis patients that needs to be differentiated from other differential diagnoses, including, but not limited to, inflammatory breast carcinoma, mastitis, lymphedema, and congestive heart failure. All reports of similar cases in the available literature have described improvement or resolution of the edema after treatment. Herein, we report and discuss the pathophysiology of breast edema formation in a patient who presented with massive left-sided breast edema 7 years after being diagnosed with central venous stenosis. Medical and minimally invasive therapy had not been successful, so she underwent reduction mammoplasty to relieve the symptoms.

  11. On the Masses of the quasi-stellar objects

    International Nuclear Information System (INIS)

    Burbidge, G.; Perry, J.

    1976-01-01

    If it is assumed that the gas giving rise to the emission and absorption lines in quasi-stellar objects has been driven out of the central object by radiation pressure, arguments based on the dynamics of radiation-driven gas flows enable us to establish limits on the central masses and the rates of mass loss. For QSOs at cosmological distances it is found that the masses of the central objects must lie in the range 5 x 10 7 M/sub sun/approximately-less-thanMapproximately-less-than2 x 10 9 m/sub sun/ and that the mass loss rates should be M/Mapprox. =10 -7 yr -1 . If the QSOs are local objects, the upper limits to the masses are about 2 x 10 7 M/sub sun/

  12. Geology, lithogeochemistry and paleotectonic setting of the host sequence to the Kangasjärvi Zn-Cu deposit, central Finland: implications for volcanogenic massive sulphide exploration in the Vihanti-Pyhäsalmi district

    Directory of Open Access Journals (Sweden)

    Michael D. Roberts

    2004-01-01

    Full Text Available The Kangasjärvi Zn-Cu deposit is a highly deformed and metamorphosed Paleoproterozoic volcanogenic massive sulphide (VMS deposit located in the Vihanti-Pyhäsalmi base metal mining district of central Finland. The host sequence to the deposit, referred to as the Inner Volcanic Sequence (IVS, is comprised of a bimodal suite of metavolcanic rocks and a regionally extensive tonalite-trondhjemite gneiss (sub-volcanic intrusions?. A separate and perhaps younger sequence of mafic volcanic rocks, with irregular intervals of undifferentiated intermediate to felsic schists and metalimestones, referred to as the Outer Volcanic Sequence (OVS, are separated from the IVS sequence by intervals of metagreywacke and U-P-bearing graphitic schists. A stratigraphic scheme for rocks within the IVS is proposed based on outcrop observations, locally preserved volcanic textures, aspects of seafloor-related hydrothermal alteration and lithogeochemistry. In this scheme, rare andesites form the lowermostvolcanic stratigraphy and are overlain by typical island-arc basalts that were erupted in a subaqueous setting. Tonalite-trondhjemite subvolcanic intrusions were locally emplaced within andesites and coeval rhyolites were extruded on the basaltic substrate. The extrusion of rhyolites, including high-silica rhyolites, was coeval with regional-scale, pre-metamorphic seafloor hydrothermal alteration and local sulphide mineralization. Extensively altered rhyolites envelope massive sulphides and are underlain by altered basalts. The latter rocks are now characterized by a variety of low-variance metamorphic mineral assemblages (e.g. orthoamphibole-cordierite rocks and define a domain of intense pre-metamorphic chlorite ± sericite alteration in the stratigraphic footwall of the deposit. The altered nature of these rocks is attributed to reaction with seawater-related hydrothermal fluids within a zone of upflow at or near the seafloor. The fundamental controls on convective

  13. MASSIVE BLACK HOLES IN STELLAR SYSTEMS: 'QUIESCENT' ACCRETION AND LUMINOSITY

    International Nuclear Information System (INIS)

    Volonteri, M.; Campbell, D.; Mateo, M.; Dotti, M.

    2011-01-01

    Only a small fraction of local galaxies harbor an accreting black hole, classified as an active galactic nucleus. However, many stellar systems are plausibly expected to host black holes, from globular clusters to nuclear star clusters, to massive galaxies. The mere presence of stars in the vicinity of a black hole provides a source of fuel via mass loss of evolved stars. In this paper, we assess the expected luminosities of black holes embedded in stellar systems of different sizes and properties, spanning a large range of masses. We model the distribution of stars and derive the amount of gas available to a central black hole through a geometrical model. We estimate the luminosity of the black holes under simple, but physically grounded, assumptions on the accretion flow. Finally, we discuss the detectability of 'quiescent' black holes in the local universe.

  14. Massive stars in the Sagittarius Dwarf Irregular Galaxy

    Science.gov (United States)

    Garcia, Miriam

    2018-02-01

    Low metallicity massive stars hold the key to interpret numerous processes in the past Universe including re-ionization, starburst galaxies, high-redshift supernovae, and γ-ray bursts. The Sagittarius Dwarf Irregular Galaxy [SagDIG, 12+log(O/H) = 7.37] represents an important landmark in the quest for analogues accessible with 10-m class telescopes. This Letter presents low-resolution spectroscopy executed with the Gran Telescopio Canarias that confirms that SagDIG hosts massive stars. The observations unveiled three OBA-type stars and one red supergiant candidate. Pending confirmation from high-resolution follow-up studies, these could be the most metal-poor massive stars of the Local Group.

  15. Massive IIA string theory and Matrix theory compactification

    International Nuclear Information System (INIS)

    Lowe, David A.; Nastase, Horatiu; Ramgoolam, Sanjaye

    2003-01-01

    We propose a Matrix theory approach to Romans' massive Type IIA supergravity. It is obtained by applying the procedure of Matrix theory compactifications to Hull's proposal of the massive Type IIA string theory as M-theory on a twisted torus. The resulting Matrix theory is a super-Yang-Mills theory on large N three-branes with a space-dependent noncommutativity parameter, which is also independently derived by a T-duality approach. We give evidence showing that the energies of a class of physical excitations of the super-Yang-Mills theory show the correct symmetry expected from massive Type IIA string theory in a lightcone quantization

  16. Conserved charges of minimal massive gravity coupled to scalar field

    Science.gov (United States)

    Setare, M. R.; Adami, H.

    2018-02-01

    Recently, the theory of topologically massive gravity non-minimally coupled to a scalar field has been proposed, which comes from the Lorentz-Chern-Simons theory (JHEP 06, 113, 2015), a torsion-free theory. We extend this theory by adding an extra term which makes the torsion to be non-zero. We show that the BTZ spacetime is a particular solution to this theory in the case where the scalar field is constant. The quasi-local conserved charge is defined by the concept of the generalized off-shell ADT current. Also a general formula is found for the entropy of the stationary black hole solution in context of the considered theory. The obtained formulas are applied to the BTZ black hole solution in order to obtain the energy, the angular momentum and the entropy of this solution. The central extension term, the central charges and the eigenvalues of the Virasoro algebra generators for the BTZ black hole solution are thus obtained. The energy and the angular momentum of the BTZ black hole using the eigenvalues of the Virasoro algebra generators are calculated. Also, using the Cardy formula, the entropy of the BTZ black hole is found. It is found that the results obtained in two different ways exactly match, just as expected.

  17. Conserved charges of minimal massive gravity coupled to scalar field

    International Nuclear Information System (INIS)

    Setare, M.R.; Adami, H.

    2018-01-01

    Recently, the theory of topologically massive gravity non-minimally coupled to a scalar field has been proposed, which comes from the Lorentz-Chern-Simons theory (JHEP 06, 113, 2015), a torsion-free theory. We extend this theory by adding an extra term which makes the torsion to be non-zero. We show that the BTZ spacetime is a particular solution to this theory in the case where the scalar field is constant. The quasi-local conserved charge is defined by the concept of the generalized off-shell ADT current. Also a general formula is found for the entropy of the stationary black hole solution in context of the considered theory. The obtained formulas are applied to the BTZ black hole solution in order to obtain the energy, the angular momentum and the entropy of this solution. The central extension term, the central charges and the eigenvalues of the Virasoro algebra generators for the BTZ black hole solution are thus obtained. The energy and the angular momentum of the BTZ black hole using the eigenvalues of the Virasoro algebra generators are calculated. Also, using the Cardy formula, the entropy of the BTZ black hole is found. It is found that the results obtained in two different ways exactly match, just as expected. (orig.)

  18. Conserved charges of minimal massive gravity coupled to scalar field

    Energy Technology Data Exchange (ETDEWEB)

    Setare, M.R.; Adami, H. [University of Kurdistan, Department of Science, Sanandaj (Iran, Islamic Republic of)

    2018-02-15

    Recently, the theory of topologically massive gravity non-minimally coupled to a scalar field has been proposed, which comes from the Lorentz-Chern-Simons theory (JHEP 06, 113, 2015), a torsion-free theory. We extend this theory by adding an extra term which makes the torsion to be non-zero. We show that the BTZ spacetime is a particular solution to this theory in the case where the scalar field is constant. The quasi-local conserved charge is defined by the concept of the generalized off-shell ADT current. Also a general formula is found for the entropy of the stationary black hole solution in context of the considered theory. The obtained formulas are applied to the BTZ black hole solution in order to obtain the energy, the angular momentum and the entropy of this solution. The central extension term, the central charges and the eigenvalues of the Virasoro algebra generators for the BTZ black hole solution are thus obtained. The energy and the angular momentum of the BTZ black hole using the eigenvalues of the Virasoro algebra generators are calculated. Also, using the Cardy formula, the entropy of the BTZ black hole is found. It is found that the results obtained in two different ways exactly match, just as expected. (orig.)

  19. THE HST/ACS COMA CLUSTER SURVEY. IV. INTERGALACTIC GLOBULAR CLUSTERS AND THE MASSIVE GLOBULAR CLUSTER SYSTEM AT THE CORE OF THE COMA GALAXY CLUSTER

    International Nuclear Information System (INIS)

    Peng, Eric W.; Ferguson, Henry C.; Goudfrooij, Paul; Hammer, Derek; Lucey, John R.; Marzke, Ronald O.; Puzia, Thomas H.; Carter, David; Balcells, Marc; Bridges, Terry; Chiboucas, Kristin; Del Burgo, Carlos; Graham, Alister W.; Guzman, Rafael; Hudson, Michael J.; Matkovic, Ana

    2011-01-01

    Intracluster stellar populations are a natural result of tidal interactions in galaxy clusters. Measuring these populations is difficult, but important for understanding the assembly of the most massive galaxies. The Coma cluster of galaxies is one of the nearest truly massive galaxy clusters and is host to a correspondingly large system of globular clusters (GCs). We use imaging from the HST/ACS Coma Cluster Survey to present the first definitive detection of a large population of intracluster GCs (IGCs) that fills the Coma cluster core and is not associated with individual galaxies. The GC surface density profile around the central massive elliptical galaxy, NGC 4874, is dominated at large radii by a population of IGCs that extend to the limit of our data (R +4000 -5000 (systematic) IGCs out to this radius, and that they make up ∼70% of the central GC system, making this the largest GC system in the nearby universe. Even including the GC systems of other cluster galaxies, the IGCs still make up ∼30%-45% of the GCs in the cluster core. Observational limits from previous studies of the intracluster light (ICL) suggest that the IGC population has a high specific frequency. If the IGC population has a specific frequency similar to high-S N dwarf galaxies, then the ICL has a mean surface brightness of μ V ∼ 27 mag arcsec -2 and a total stellar mass of roughly 10 12 M sun within the cluster core. The ICL makes up approximately half of the stellar luminosity and one-third of the stellar mass of the central (NGC 4874+ICL) system. The color distribution of the IGC population is bimodal, with blue, metal-poor GCs outnumbering red, metal-rich GCs by a ratio of 4:1. The inner GCs associated with NGC 4874 also have a bimodal distribution in color, but with a redder metal-poor population. The fraction of red IGCs (20%), and the red color of those GCs, implies that IGCs can originate from the halos of relatively massive, L* galaxies, and not solely from the disruption of

  20. Massively Parallel QCD

    International Nuclear Information System (INIS)

    Soltz, R; Vranas, P; Blumrich, M; Chen, D; Gara, A; Giampap, M; Heidelberger, P; Salapura, V; Sexton, J; Bhanot, G

    2007-01-01

    The theory of the strong nuclear force, Quantum Chromodynamics (QCD), can be numerically simulated from first principles on massively-parallel supercomputers using the method of Lattice Gauge Theory. We describe the special programming requirements of lattice QCD (LQCD) as well as the optimal supercomputer hardware architectures that it suggests. We demonstrate these methods on the BlueGene massively-parallel supercomputer and argue that LQCD and the BlueGene architecture are a natural match. This can be traced to the simple fact that LQCD is a regular lattice discretization of space into lattice sites while the BlueGene supercomputer is a discretization of space into compute nodes, and that both are constrained by requirements of locality. This simple relation is both technologically important and theoretically intriguing. The main result of this paper is the speedup of LQCD using up to 131,072 CPUs on the largest BlueGene/L supercomputer. The speedup is perfect with sustained performance of about 20% of peak. This corresponds to a maximum of 70.5 sustained TFlop/s. At these speeds LQCD and BlueGene are poised to produce the next generation of strong interaction physics theoretical results

  1. Measuring the total and baryonic mass profiles of the very massive CASSOWARY 31 strong lens

    DEFF Research Database (Denmark)

    Grillo, Claudio; Christensen, L.; Gallazzi, A.

    2013-01-01

    We investigate the total and baryonic mass distributions in deflector number 31 (CSWA 31) of the Cambridge And Sloan Survey Of Wide ARcs in the skY (CASSOWARY). We confirm spectroscopically a four-image lensing system at redshift 1.4870 with Very Large Telescope/X-shooter observations. The lensed...... find that the CSWA 31 deflector has properties suggesting it to be among the most distant and massive fossil systems studied so far. The unusually strong central dark matter dominance and the possible fossil nature of this system render it an interesting target for detailed tests of cosmological models...

  2. Interactions between massive dark halos and warped disks

    NARCIS (Netherlands)

    Kuijken, K; Persic, M; Salucci, P

    1997-01-01

    The normal mode theory for warping of galaxy disks, in which disks are assumed to be tilted with respect to the equator of a massive, flattened dark halo, assumes a rigid, fixed halo. However, consideration of the back-reaction by a misaligned disk on a massive particle halo shows there to be strong

  3. Reconstructing the massive black hole cosmic history through gravitational waves

    International Nuclear Information System (INIS)

    Sesana, Alberto; Gair, Jonathan; Berti, Emanuele; Volonteri, Marta

    2011-01-01

    The massive black holes we observe in galaxies today are the natural end-product of a complex evolutionary path, in which black holes seeded in proto-galaxies at high redshift grow through cosmic history via a sequence of mergers and accretion episodes. Electromagnetic observations probe a small subset of the population of massive black holes (namely, those that are active or those that are very close to us), but planned space-based gravitational wave observatories such as the Laser Interferometer Space Antenna (LISA) can measure the parameters of 'electromagnetically invisible' massive black holes out to high redshift. In this paper we introduce a Bayesian framework to analyze the information that can be gathered from a set of such measurements. Our goal is to connect a set of massive black hole binary merger observations to the underlying model of massive black hole formation. In other words, given a set of observed massive black hole coalescences, we assess what information can be extracted about the underlying massive black hole population model. For concreteness we consider ten specific models of massive black hole formation, chosen to probe four important (and largely unconstrained) aspects of the input physics used in structure formation simulations: seed formation, metallicity ''feedback'', accretion efficiency and accretion geometry. For the first time we allow for the possibility of 'model mixing', by drawing the observed population from some combination of the 'pure' models that have been simulated. A Bayesian analysis allows us to recover a posterior probability distribution for the ''mixing parameters'' that characterize the fractions of each model represented in the observed distribution. Our work shows that LISA has enormous potential to probe the underlying physics of structure formation.

  4. Massive vulval oedema in multiple pregnancies at Bugando Medical ...

    African Journals Online (AJOL)

    In this report we describe two cases of massive vulval oedema seen in two ... passage of yellow-whitish discharge per vagina (Figure 1). Examination revealed massive oedema, and digital vaginal examination was difficult due to tenderness.

  5. Remarks on search methods for stable, massive, elementary particles

    International Nuclear Information System (INIS)

    Perl, Martin L.

    2001-01-01

    This paper was presented at the 69th birthday celebration of Professor Eugene Commins, honoring his research achievements. These remarks are about the experimental techniques used in the search for new stable, massive particles, particles at least as massive as the electron. A variety of experimental methods such as accelerator experiments, cosmic ray studies, searches for halo particles in the galaxy and searches for exotic particles in bulk matter are described. A summary is presented of the measured limits on the existence of new stable, massive particle

  6. Dual descriptions of massive spin-2 particles in D=3+1

    International Nuclear Information System (INIS)

    Dalmazi, Denis

    2013-01-01

    Full text: Since the sixties (last century) one speculates on the effects of a possible (tiny) mass for the graviton. One expects a decrease in the gravitational interaction at large distances which comes handy regarding the experimental data of the last 15 years on the accelerated expansion of the universe. There has been a growing interest in massive quantum gravity in the last years. Almost all recent works are built up on the top of a free (quadratic) action for a massive spin-2 particle known as massive Fierz-Pauli (FP) theory which has first appeared in 1939. In this theory the basic field is a symmetric rank-2 tensor. It is a common belief in the massive gravity community that the massive FP theory is the unique self-consistent (ghost free, Poincare covariant, correct number of degrees of freedom) description of massive spin-2 particles in terms of a rank-2 tensor. We have shown recently that there are other possibilities if we start with a general (non-symmetric) rank-2 tensor. Here we show how our previous work is related with the well known massive FP theory via the introduction of spectators fields of rank-0 (scalar) and rank-1 (vector). We comment on the introduction of interacting vertices and how they affect the free duality with the massive FP theory (author)

  7. Quark–hadron phase transition in massive gravity

    Energy Technology Data Exchange (ETDEWEB)

    Atazadeh, K., E-mail: atazadeh@azaruniv.ac.ir

    2016-11-15

    We study the quark–hadron phase transition in the framework of massive gravity. We show that the modification of the FRW cosmological equations leads to the quark–hadron phase transition in the early massive Universe. Using numerical analysis, we consider that a phase transition based on the chiral symmetry breaking after the electroweak transition, occurred at approximately 10 μs after the Big Bang to convert a plasma of free quarks and gluons into hadrons.

  8. A rare case of massive hepatosplenomegaly due to acute ...

    African Journals Online (AJOL)

    massive hepatosplenomegaly include chronic lymphoproliferative malignancies, infections (malaria, leishmaniasis) and glycogen storage diseases (Gaucher's disease).[4] In our case the probable causes of the massive hepatosplenomegaly were a combination of late presentation after symptom onset, leukaemic infiltration.

  9. A Novel Technique for Time-Centric Analysis of Massive Remotely-Sensed Datasets

    Directory of Open Access Journals (Sweden)

    Glenn E. Grant

    2015-04-01

    Full Text Available Analyzing massive remotely-sensed datasets presents formidable challenges. The volume of satellite imagery collected often outpaces analytical capabilities, however thorough analyses of complete datasets may provide new insights into processes that would otherwise be unseen. In this study we present a novel, object-oriented approach to storing, retrieving, and analyzing large remotely-sensed datasets. The objective is to provide a new structure for scalable storage and rapid, Internet-based analysis of climatology data. The concept of a “data rod” is introduced, a conceptual data object that organizes time-series information into a temporally-oriented vertical column at any given location. To demonstrate one possible use, we ingest 25 years of Greenland imagery into a series of pure-object databases, then retrieve and analyze the data. The results provide a basis for evaluating the database performance and scientific analysis capabilities. The project succeeds in demonstrating the effectiveness of the prototype database architecture and analysis approach, not because new scientific information is discovered, but because quality control issues are revealed in the source data that had gone undetected for years.

  10. The SINS/zC-SINF survey of z ∼ 2 galaxy kinematics: Evidence for powerful active galactic nucleus-driven nuclear outflows in massive star-forming galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Förster Schreiber, N. M.; Genzel, R.; Kurk, J. D.; Lutz, D.; Tacconi, L. J.; Wuyts, S.; Bandara, K.; Buschkamp, P.; Davies, R.; Eisenhauer, F.; Lang, P. [Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Newman, S. F. [Department of Astronomy, Hearst Field Annex, University of California, Berkeley, CA 94720 (United States); Burkert, A. [Universitäts-Sternwarte, Ludwig-Maximilians-Universität, Scheinerstrasse 1, D-81679 München (Germany); Carollo, C. M.; Lilly, S. J. [Institute for Astronomy, Department of Physics, Eidgenössische Technische Hochschule, 8093-CH Zürich (Switzerland); Cresci, G. [Istituto Nazionale di Astrofisica—Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Daddi, E. [CEA Saclay, DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); Hicks, E. K. S. [Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195-1580 (United States); Mainieri, V. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Mancini, C. [Istituto Nazionale di Astrofisica—Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); and others

    2014-05-20

    We report the detection of ubiquitous powerful nuclear outflows in massive (≥10{sup 11} M {sub ☉}) z ∼ 2 star-forming galaxies (SFGs), which are plausibly driven by an active galactic nucleus (AGN). The sample consists of the eight most massive SFGs from our SINS/zC-SINF survey of galaxy kinematics with the imaging spectrometer SINFONI, six of which have sensitive high-resolution adaptive optics-assisted observations. All of the objects are disks hosting a significant stellar bulge. The spectra in their central regions exhibit a broad component in Hα and forbidden [N II] and [S II] line emission, with typical velocity FWHM ∼ 1500 km s{sup –1}, [N II]/Hα ratio ≈ 0.6, and intrinsic extent of 2-3 kpc. These properties are consistent with warm ionized gas outflows associated with Type 2 AGN, the presence of which is confirmed via independent diagnostics in half the galaxies. The data imply a median ionized gas mass outflow rate of ∼60 M {sub ☉} yr{sup –1} and mass loading of ∼3. At larger radii, a weaker broad component is detected but with lower FWHM ∼485 km s{sup –1} and [N II]/Hα ≈ 0.35, characteristic for star formation-driven outflows as found in the lower-mass SINS/zC-SINF galaxies. The high inferred mass outflow rates and frequent occurrence suggest that the nuclear outflows efficiently expel gas out of the centers of the galaxies with high duty cycles and may thus contribute to the process of star formation quenching in massive galaxies. Larger samples at high masses will be crucial in confirming the importance and energetics of the nuclear outflow phenomenon and its connection to AGN activity and bulge growth.

  11. Constraints on Massive Axion-Like Particles from X-ray Observations of NGC1275

    Science.gov (United States)

    Chen, Linhan; Conlon, Joseph P.

    2018-06-01

    If axion-like particles (ALPs) exist, photons can convert to ALPs on passage through regions containing magnetic fields. The magnetised intracluster medium of large galaxy clusters provides a region that is highly efficient at ALP-photon conversion. X-ray observations of Active Galactic Nuclei (AGNs) located within galaxy clusters can be used to search for and constrain ALPs, as photon-ALP conversion would lead to energy-dependent quasi-sinusoidal modulations in the X-ray spectrum of an AGN. We use Chandra observations of the central AGN of the Perseus Cluster, NGC1275, to place bounds on massive ALPs up to ma ˜ 10-11eV, extending previous work that used this dataset to constrain massless ALPs.

  12. Massive vector particles tunneling from black holes influenced by the generalized uncertainty principle

    Directory of Open Access Journals (Sweden)

    Xiang-Qian Li

    2016-12-01

    Full Text Available This study considers the generalized uncertainty principle, which incorporates the central idea of large extra dimensions, to investigate the processes involved when massive spin-1 particles tunnel from Reissner–Nordstrom and Kerr black holes under the effects of quantum gravity. For the black hole, the quantum gravity correction decelerates the increase in temperature. Up to O(1Mf2, the corrected temperatures are affected by the mass and angular momentum of the emitted vector bosons. In addition, the temperature of the Kerr black hole becomes uneven due to rotation. When the mass of the black hole approaches the order of the higher dimensional Planck mass Mf, it stops radiating and yields a black hole remnant.

  13. Scalable and massively parallel Monte Carlo photon transport simulations for heterogeneous computing platforms.

    Science.gov (United States)

    Yu, Leiming; Nina-Paravecino, Fanny; Kaeli, David; Fang, Qianqian

    2018-01-01

    We present a highly scalable Monte Carlo (MC) three-dimensional photon transport simulation platform designed for heterogeneous computing systems. Through the development of a massively parallel MC algorithm using the Open Computing Language framework, this research extends our existing graphics processing unit (GPU)-accelerated MC technique to a highly scalable vendor-independent heterogeneous computing environment, achieving significantly improved performance and software portability. A number of parallel computing techniques are investigated to achieve portable performance over a wide range of computing hardware. Furthermore, multiple thread-level and device-level load-balancing strategies are developed to obtain efficient simulations using multiple central processing units and GPUs. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  14. Massive antenatal fetomaternal hemorrhage

    DEFF Research Database (Denmark)

    Dziegiel, Morten Hanefeld; Koldkjaer, Ole; Berkowicz, Adela

    2005-01-01

    Massive fetomaternal hemorrhage (FMH) can lead to life-threatening anemia. Quantification based on flow cytometry with anti-hemoglobin F (HbF) is applicable in all cases but underestimation of large fetal bleeds has been reported. A large FMH from an ABO-compatible fetus allows an estimation...

  15. Central venous stenosis in haemodialysis patients without a previous history of catheter placement

    International Nuclear Information System (INIS)

    Oguzkurt, Levent; Tercan, Fahri; Yildirim, Sedat; Torun, Dilek

    2005-01-01

    Objective: To evaluate dialysis history, imaging findings and outcome of endovascular treatment in six patients with central venous stenosis without a history of previous catheter placement. Material and methods: Between April 2000 and June 2004, six (10%) of 57 haemodialysis patients had stenosis of a central vein without a previous central catheter placement. Venography findings and outcome of endovascular treatment in these six patients were retrospectively evaluated. Patients were three women (50%) and three men aged 32-60 years (mean age: 45 years) and all had massive arm swelling as the main complaint. The vascular accesses were located at the elbow in five patients and at the wrist in one patient. Results: Three patients had stenosis of the left subclavian vein and three patients had stenosis of the left brachiocephalic vein. The mean duration of the vascular accesses from the time of creation was 25.1 months. Flow volumes of the vascular access were very high in four patients who had flow volume measurement. The mean flow volume was 2347 ml/min. One of three patients with brachiocephalic vein stenosis had compression of the vein by the brachiocephalic artery. All the lesions were first treated with balloon angioplasty and two patients required stent placement on long term. Number of interventions ranged from 1 to 4 (mean: 2.1). Symptoms resolved in five patients and improved in one patient who had a stent placed in the left BCV. Conclusion: Central venous stenosis in haemodialysis patients without a history of central venous catheterization tends to occur or be manifested in patients with a proximal permanent vascular access with high flow rates. Balloon angioplasty with or without stent placement offers good secondary patency rates in mid-term

  16. WHAT SETS THE INITIAL ROTATION RATES OF MASSIVE STARS?

    International Nuclear Information System (INIS)

    Rosen, Anna L.; Krumholz, Mark R.; Ramirez-Ruiz, Enrico

    2012-01-01

    The physical mechanisms that set the initial rotation rates in massive stars are a crucial unknown in current star formation theory. Observations of young, massive stars provide evidence that they form in a similar fashion to their low-mass counterparts. The magnetic coupling between a star and its accretion disk may be sufficient to spin down low-mass pre-main-sequence (PMS) stars to well below breakup at the end stage of their formation when the accretion rate is low. However, we show that these magnetic torques are insufficient to spin down massive PMS stars due to their short formation times and high accretion rates. We develop a model for the angular momentum evolution of stars over a wide range in mass, considering both magnetic and gravitational torques. We find that magnetic torques are unable to spin down either low-mass or high-mass stars during the main accretion phase, and that massive stars cannot be spun down significantly by magnetic torques during the end stage of their formation either. Spin-down occurs only if massive stars' disk lifetimes are substantially longer or their magnetic fields are much stronger than current observations suggest.

  17. A new direction for dark matter research: intermediate-mass compact halo objects

    Energy Technology Data Exchange (ETDEWEB)

    Chapline, George F. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA (United States); Frampton, Paul H., E-mail: george.chapline@gmail.com, E-mail: paul.h.frampton@gmail.com [15 Summerheights, 29 Water Eaton Road, Oxford OX2 7PG (United Kingdom)

    2016-11-01

    The failure to find evidence for elementary particles that could serve as the constituents of dark matter brings to mind suggestions that dark matter might consist of massive compact objects (MACHOs). In particular, it has recently been argued that MACHOs with masses > 15 M {sub ⊙} may have been prolifically produced at the onset of the big bang. Although a variety of astrophysical signatures for primordial MACHOs with masses in this range have been discussed in the literature, we favor a strategy that uses the potential for magnification of stars outside our galaxy due to gravitational microlensing of these stars by MACHOs in the halo of our galaxy. We point out that the effect of the motion of the Earth on the shape of the micro-lensing brightening curves provides a promising approach to testing over the course of next several years the hypothesis that dark matter consists of massive compact objects.

  18. Wolf-Rayet stars in the central region of the Milky Way

    Science.gov (United States)

    Hamann, Wolf-Rainer; Graefener, Goetz; Oskinova, Lidia; Zinnecker, Hans

    2004-09-01

    We propose to take mid-IR spectra of two Wolf-Rayet stars in the inner part of our Galaxy, within 30pc projected distance from the central Black Hole. Massive stars dominate the central galactic region by their mass-loss and ionizing radiation. A quantitative analysis of this stellar inventory is essential for understanding the energy, momentum and mass budget, for instance with respect to the feeding of the central black hole. Our group developed a highly advanced model code for the expanding atmospheres of WR stars. Recently we extended the spectrum synthesis to IR wavelengths. These models will be applied for the analysis of the Spitzer IRS data. The proposed mid-IR observations will provide a wide spectral range with many lines which are needed to determine the stellar parameters, such as stellar luminosity, effective temperature, mass-loss rate and chemical composition. Near-IR spectra of the program stars are available and will augment the analysis. The capability of our code to reproduce the observed mid-IR spectrum of a WN star has been demonstrated. The two targets we selected are sufficiently isolated, while the Galactic center cluster is too crowded for the size of Spitzer's spectrograph slit. As estimated from the K-band spectra, one of the stars (WR102ka) is of very late subtype (WN9), while the other star (WR102c) has the early subtype WN6. Hence they represent different stages in the evolutionary sequence of massive stars, the late-WN just having entered the Wolf-Rayet phase and the early WN being further evolved. We expect that the parameters of massive stars in the inner galaxy differ from the usual Galactic population. One reason is that higher metallicity should lead to stronger mass-loss, which affects the stellar evolution. The Spitzer IRS, with its high sensitivity, provides a unique opportunity to study representative members of the stellar population in the vicinity of the Galactic center.

  19. GIVETIAN–FRASNIAN BOUNDARY CONODONTS FROM KERMAN PROVINCE, CENTRAL IRAN

    OpenAIRE

    GHOLAMALIAN, HOSSEIN; HAIRAPETIAN, VACHIK; BARFEHEI, NAHID; MANGELIAN, SOHEYLA; FARIDI, PARVANEH

    2013-01-01

    The Middle - Late Devonian boundary is investigated based on twenty-two conodont species and subspecies from three sections in the north and west of Kerman, southeastern central Iran. Upper Givetian - lower Frasnian carbonates of the basal part of the Bahram Formation transgressively overlie the sandstone beds of the top of (?) Early - Middle Devonian Padeha Formation. These massive skeletal limestones encompass the G-F boundary. The base of Frasnian is identified by the appearance of early f...

  20. Phases of massive gravity

    CERN Document Server

    Dubovsky, S L

    2004-01-01

    We systematically study the most general Lorentz-violating graviton mass invariant under three-dimensional Eucledian group using the explicitly covariant language. We find that at general values of mass parameters the massive graviton has six propagating degrees of freedom, and some of them are ghosts or lead to rapid classical instabilities. However, there is a number of different regions in the mass parameter space where massive gravity can be described by a consistent low-energy effective theory with cutoff $\\sim\\sqrt{mM_{Pl}}$ free of rapid instabilities and vDVZ discontinuity. Each of these regions is characterized by certain fine-tuning relations between mass parameters, generalizing the Fierz--Pauli condition. In some cases the required fine-tunings are consequences of the existence of the subgroups of the diffeomorphism group that are left unbroken by the graviton mass. We found two new cases, when the resulting theories have a property of UV insensitivity, i.e. remain well behaved after inclusion of ...

  1. Central station market development strategies for photovoltaics

    Science.gov (United States)

    1980-01-01

    Federal market development strategies designed to accelerate the market penetration of central station applications of photovoltaic energy system are analyzed. Since no specific goals were set for the commercialization of central station applications, strategic principles are explored which, when coupled with specific objectives for central stations, can produce a market development implementation plan. The study includes (1) background information on the National Photovoltaic Program, photovoltaic technology, and central stations; (2) a brief market assessment; (3) a discussion of the viewpoints of the electric utility industry with respect to solar energy; (4) a discussion of commercialization issues; and (5) strategy principles. It is recommended that a set of specific goals and objectives be defined for the photovoltaic central station program, and that these goals and objectives evolve into an implementation plan that identifies the appropriate federal role.

  2. Massive Multiplayer Online Gaming: A Research Framework for Military Training and Education

    Science.gov (United States)

    2005-03-01

    Effects of violent video games on aggressive behavior, aggressive cognition, physiological arousal, and prosocial behavior: A meta...Massive Multiplayer Online Games 2.1 Massive Multiplayer Online Games Defined Massive multiplayer online games (MMOGs) allow users to interact ...2002) suggested various principles for group design and interactions in “massively multiplayer games ” (p. 1). In particular, he agued that it

  3. [The Object Permanence Fallacy.] Commentary.

    Science.gov (United States)

    Bradley, Ben S.

    1996-01-01

    Suggests that Greenberg's challenge to the centrality of object permanence in developmental thinking reveals that developmentalists' theories about childhood speak about their own self-images. Notes that developmentalists have been guilty of not only the object permanence fallacy but also the genetic fallacy, or the mistaken belief that describing…

  4. The diversity of neutron stars: Nearby thermally emitting neutron stars and the compact central objects in supernova remnants

    Science.gov (United States)

    Kaplan, David L.

    Neutron stars are invaluable tools for exploring stellar death, the physics of ultra-dense matter, and the effects of extremely strong magnetic fields. The observed population of neutron stars is dominated by the > 1000 radio pulsars, but there are distinct sub-populations that, while fewer in number, can have significant impact on our understanding of the issues mentioned above. These populations are the nearby isolated neutron stars discovered by ROSAT, and the central compact objects in supernova remnants. The studies of both of these populations have been greatly accelerated in recent years through observations with the Chandra X-ray Observatory and the XMM-Newton telescope. First, we discuss radio, optical, and X-ray observations of the nearby neutron stars aimed at determining their relation to the Galactic neutron star population and at unraveling their complex physical processes by determining the basic astronomical parameters that define the population -- instances, ages, and magnetic fields -- the uncertainties in which limit any attempt to derive basic physical parameters for these objects. We conclude that these sources are 10^6 year-old cooling neutron stars with magnetic fields above 10^13 G. Second, we describe the hollow supernova remnant problem: why many of the supernova remnants in the Galaxy have no indication central neutron stars. We have undertaken an X-ray census of neutron stars in a volume-limited sample of Galactic supernova remnants, and from it conclude that either many supernovae do not produce neutron stars contrary to expectation, or that neutron stars can have a wide range in cooling behavior that makes many sources disappear from the X-ray sky.

  5. Massive coordination of dispersed generation using PowerMatcher based software agents

    International Nuclear Information System (INIS)

    Kamphuis, I.G.; Hommelberg, M.P.F.; Warmer, C.J.; Kok, J.K.

    2007-01-01

    One of the outcomes of the EU-Fifth framework CRISP-project (http://crisp.ecn.nl/), has been the development of a real-time control strategy based on the application of distributed intelligence (ICT) to coordinate demand and supply in electricity grids. This PowerMatcher approach has been validated in two real-life and real-time field tests. The experiments aimed at controlled coordination of dispersed electricity suppliers (DG-RES) and demanders in distributed grids enabled by ICT-networks. Optimization objectives for the technology in the tests were minimization of imbalance in a commercial portfolio and mitigation of strong load variations in a distribution network with residential micro-CHPs. With respect to the number of ICT-nodes, the field tests were on a relatively small-scale. However, application of the technology has yielded some very encouraging results in both occasions. In the present paper, lessons learned from the field experiments are discussed. Furthermore, it contains an account of the roadmap for scaling up these field-tests with a larger number of nodes and with more diverse appliance/installation types. Due to its autonomous decision making agent-paradigm, the PowerMatcher software technology is expected to be widely more scaleable than central coordination approaches. Indeed, it is based on microeconomic theory and is expected to work best if it is applied on a massive scale in transparent market settings. A set of various types of supply and demand appliances was defined and implemented in a PowerMatcher software simulation environment. A massive amount of these PowerMatcher node-agents each representing such a devicetype was utilized in a number of scenario calculations. As the production of DG-RES-resources and the demand profiles are strongly dependent on the time-of-year, climate scenarios leading to operational snapshots of the cluster were taken for a number of representative periods. The results of these larger scale simulations as

  6. Cosmological stability bound in massive gravity and bigravity

    International Nuclear Information System (INIS)

    Fasiello, Matteo; Tolley, Andrew J.

    2013-01-01

    We give a simple derivation of a cosmological bound on the graviton mass for spatially flat FRW solutions in massive gravity with an FRW reference metric and for bigravity theories. This bound comes from the requirement that the kinetic term of the helicity zero mode of the graviton is positive definite. The bound is dependent only on the parameters in the massive gravity potential and the Hubble expansion rate for the two metrics. We derive the decoupling limit of bigravity and FRW massive gravity, and use this to give an independent derivation of the cosmological bound. We recover our previous results that the tension between satisfying the Friedmann equation and the cosmological bound is sufficient to rule out all observationally relevant FRW solutions for massive gravity with an FRW reference metric. In contrast, in bigravity this tension is resolved due to different nature of the Vainshtein mechanism. We find that in bigravity theories there exists an FRW solution with late-time self-acceleration for which the kinetic terms for the helicity-2, helicity-1 and helicity-0 are generically nonzero and positive making this a compelling candidate for a model of cosmic acceleration. We confirm that the generalized bound is saturated for the candidate partially massless (bi)gravity theories but the existence of helicity-1/helicity-0 interactions implies the absence of the conjectured partially massless symmetry for both massive gravity and bigravity

  7. STRONG GRAVITATIONAL LENSING BY THE SUPER-MASSIVE cD GALAXY IN ABELL 3827

    International Nuclear Information System (INIS)

    Carrasco, E. R.; Gomez, P. L.; Lee, H.; Diaz, R.; Bergmann, M.; Turner, J. E. H.; Miller, B. W.; West, M. J.; Verdugo, T.

    2010-01-01

    We have discovered strong gravitational lensing features in the core of the nearby cluster Abell 3827 by analyzing Gemini South GMOS images. The most prominent strong lensing feature is a highly magnified, ring-shaped configuration of four images around the central cD galaxy. GMOS spectroscopic analysis puts this source at z ∼ 0.2. Located ∼20'' away from the central galaxy is a secondary tangential arc feature which has been identified as a background galaxy with z ∼ 0.4. We have modeled the gravitational potential of the cluster core, taking into account the mass from the cluster, the brightest cluster galaxy (BCG), and other galaxies. We derive a total mass of (2.7 ± 0.4) x 10 13 M sun within 37 h -1 kpc. This mass is an order of magnitude larger than that derived from X-ray observations. The total mass derived from lensing data suggests that the BCG in this cluster is perhaps the most massive galaxy in the nearby universe.

  8. The diverse lives of massive protoplanets in self-gravitating discs

    Science.gov (United States)

    Stamatellos, Dimitris; Inutsuka, Shu-ichiro

    2018-04-01

    Gas giant planets may form early-on during the evolution of protostellar discs, while these are relatively massive. We study how Jupiter-mass planet-seeds (termed protoplanets) evolve in massive, but gravitationally stable (Q≳1.5), discs using radiative hydrodynamic simulations. We find that the protoplanet initially migrates inwards rapidly, until it opens up a gap in the disc. Thereafter, it either continues to migrate inwards on a much longer timescale or starts migrating outwards. Outward migration occurs when the protoplanet resides within a gap with gravitationally unstable edges, as a high fraction of the accreted gas is high angular momentum gas from outside the protoplanet's orbit. The effect of radiative heating from the protoplanet is critical in determining the direction of the migration and the eccentricity of the protoplanet. Gap opening is facilitated by efficient cooling that may not be captured by the commonly used β-cooling approximation. The protoplanet initially accretes at a high rate (˜10-3MJ yr-1), and its accretion luminosity could be a few tenths of the host star's luminosity, making the protoplanet easily observable (albeit only for a short time). Due to the high gas accretion rate, the protoplanet generally grows above the deuterium-burning mass-limit. Protoplanet radiative feedback reduces its mass growth so that its final mass is near the brown dwarf-planet boundary. The fate of a young planet-seed is diverse and could vary from a gas giant planet on a circular orbit at a few AU from the central star to a brown dwarf on an eccentric, wide orbit.

  9. Wide-field Infrared Survey Explorer Observations of the Evolution of Massive Star-forming Regions

    OpenAIRE

    Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Rebull, L. M.; Padgett, D. L.; Assef, R. J.

    2012-01-01

    We present the results of a mid-infrared survey of 11 outer Galaxy massive star-forming regions and 3 open clusters with data from the Wide-field Infrared Survey Explorer (WISE). Using a newly developed photometric scheme to identify young stellar objects and exclude extragalactic contamination, we have studied the distribution of young stars within each region. These data tend to support the hypothesis that latter generations may be triggered by the interaction of winds and radiation from th...

  10. Central Park Water - a league of its own

    International Nuclear Information System (INIS)

    Wallace, Paula

    2013-01-01

    Central Park Water (CPW) is leading Australia with a unique water re-use approach at the massive Central Park mixed-use development on the Sydney CBD fringe. It is an integrated water cycle management solution, harvesting multiple water sources (from residential and commercial customers) and purifying these using world's best technologies. The eight-step purification process includes anaerobic and aerobic processes, chemical addition, membrane bioreactors, reverse osmosis, ultraviolet and chlorine addition. It meets the highest Australian standards and the recycled water is sold to customers within the precinct and outside to neighbouring communities. It results in an increased efficiency of infrastructure and easy management of peak or unexpected water demands. CPW is the first private utility to supply drinking water to commercial and residential customers under an agreement with Sydney Water.

  11. Star-disc interaction in galactic nuclei: formation of a central stellar disc

    Science.gov (United States)

    Panamarev, Taras; Shukirgaliyev, Bekdaulet; Meiron, Yohai; Berczik, Peter; Just, Andreas; Spurzem, Rainer; Omarov, Chingis; Vilkoviskij, Emmanuil

    2018-05-01

    We perform high-resolution direct N-body simulations to study the effect of an accretion disc on stellar dynamics in an active galactic nucleus (AGN). We show that the interaction of the nuclear stellar cluster (NSC) with the gaseous accretion disc (AD) leads to formation of a stellar disc in the central part of the NSC. The accretion of stars from the stellar disc on to the super-massive black hole is balanced by the capture of stars from the NSC into the stellar disc, yielding a stationary density profile. We derive the migration time through the AD to be 3 per cent of the half-mass relaxation time of the NSC. The mass and size of the stellar disc are 0.7 per cent of the mass and 5 per cent of the influence radius of the super-massive black hole. An AD lifetime shorter than the migration time would result in a less massive nuclear stellar disc. The detection of such a stellar disc could point to past activity of the hosting galactic nucleus.

  12. Fragmentation of massive dense cores down to ≲ 1000 AU: Relation between fragmentation and density structure

    International Nuclear Information System (INIS)

    Palau, Aina; Girart, Josep M.; Estalella, Robert; Fuente, Asunción; Fontani, Francesco; Sánchez-Monge, Álvaro; Commerçon, Benoit; Hennebelle, Patrick; Busquet, Gemma; Bontemps, Sylvain; Zapata, Luis A.; Zhang, Qizhou; Di Francesco, James

    2014-01-01

    In order to shed light on the main physical processes controlling fragmentation of massive dense cores, we present a uniform study of the density structure of 19 massive dense cores, selected to be at similar evolutionary stages, for which their relative fragmentation level was assessed in a previous work. We inferred the density structure of the 19 cores through a simultaneous fit of the radial intensity profiles at 450 and 850 μm (or 1.2 mm in two cases) and the spectral energy distribution, assuming spherical symmetry and that the density and temperature of the cores decrease with radius following power-laws. Even though the estimated fragmentation level is strictly speaking a lower limit, its relative value is significant and several trends could be explored with our data. We find a weak (inverse) trend of fragmentation level and density power-law index, with steeper density profiles tending to show lower fragmentation, and vice versa. In addition, we find a trend of fragmentation increasing with density within a given radius, which arises from a combination of flat density profile and high central density and is consistent with Jeans fragmentation. We considered the effects of rotational-to-gravitational energy ratio, non-thermal velocity dispersion, and turbulence mode on the density structure of the cores, and found that compressive turbulence seems to yield higher central densities. Finally, a possible explanation for the origin of cores with concentrated density profiles, which are the cores showing no fragmentation, could be related with a strong magnetic field, consistent with the outcome of radiation magnetohydrodynamic simulations.

  13. Fragmentation of massive dense cores down to ≲ 1000 AU: Relation between fragmentation and density structure

    Energy Technology Data Exchange (ETDEWEB)

    Palau, Aina; Girart, Josep M. [Institut de Ciències de l' Espai (CSIC-IEEC), Campus UAB-Facultat de Ciències, Torre C5-parell 2, E-08193 Bellaterra, Catalunya (Spain); Estalella, Robert [Departament d' Astronomia i Meteorologia (IEEC-UB), Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès, 1, E-08028 Barcelona (Spain); Fuente, Asunción [Observatorio Astronómico Nacional, P.O. Box 112, E-28803 Alcalá de Henares, Madrid (Spain); Fontani, Francesco; Sánchez-Monge, Álvaro [Osservatorio Astrofisico di Arcetri, INAF, Lago E. Fermi 5, I-50125 Firenze (Italy); Commerçon, Benoit; Hennebelle, Patrick [Laboratoire de Radioastronomie, UMR CNRS 8112, École Normale Supérieure et Observatoire de Paris, 24 rue Lhomond, F-75231 Paris Cedex 05 (France); Busquet, Gemma [INAF-Istituto di Astrofisica e Planetologia Spaziali, Area di Recerca di Tor Vergata, Via Fosso Cavaliere 100, I-00133 Roma (Italy); Bontemps, Sylvain [Université de Bordeaux, LAB, UMR 5804, F-33270 Floirac (France); Zapata, Luis A. [Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, P.O. Box 3-72, 58090 Morelia, Michoacán (Mexico); Zhang, Qizhou [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Di Francesco, James, E-mail: palau@ieec.uab.es [Department of Physics and Astronomy, University of Victoria, P.O. Box 355, STN CSC, Victoria, BC, V8W 3P6 (Canada)

    2014-04-10

    In order to shed light on the main physical processes controlling fragmentation of massive dense cores, we present a uniform study of the density structure of 19 massive dense cores, selected to be at similar evolutionary stages, for which their relative fragmentation level was assessed in a previous work. We inferred the density structure of the 19 cores through a simultaneous fit of the radial intensity profiles at 450 and 850 μm (or 1.2 mm in two cases) and the spectral energy distribution, assuming spherical symmetry and that the density and temperature of the cores decrease with radius following power-laws. Even though the estimated fragmentation level is strictly speaking a lower limit, its relative value is significant and several trends could be explored with our data. We find a weak (inverse) trend of fragmentation level and density power-law index, with steeper density profiles tending to show lower fragmentation, and vice versa. In addition, we find a trend of fragmentation increasing with density within a given radius, which arises from a combination of flat density profile and high central density and is consistent with Jeans fragmentation. We considered the effects of rotational-to-gravitational energy ratio, non-thermal velocity dispersion, and turbulence mode on the density structure of the cores, and found that compressive turbulence seems to yield higher central densities. Finally, a possible explanation for the origin of cores with concentrated density profiles, which are the cores showing no fragmentation, could be related with a strong magnetic field, consistent with the outcome of radiation magnetohydrodynamic simulations.

  14. Chronic massive rotator cuff tear in rats: in vivo evaluation of muscle force and three-dimensional histologic analysis.

    Science.gov (United States)

    Ditsios, Konstantinos; Boutsiadis, Achilleas; Kapoukranidou, Dorothea; Chatzisotiriou, Athanasios; Kalpidis, Ioannis; Albani, Maria; Christodoulou, Anastasios

    2014-12-01

    Massive rotator cuff tear repair is frequently complicated by unsatisfactory clinical results due to possible tendon retraction, muscle atrophy, and fatty degeneration. The objective of this study was the development of a chronic massive tear in a rat model and the evaluation of the muscle force in vivo and of the histologic changes in a 3- dimensional manner. To simulate massive rotator cuff tears, both the supraspinatus (SS) and the infraspinatus (IS) tendons were surgically detached from the right humerus of 15 male adult Sprague-Dawley rats. Twelve weeks postoperatively, all animals underwent isometric tension recordings of both the SS and IS muscles. Histologic analysis and image deconvolution processing were performed to estimate the presence and the distribution of atrophy in 3 dimensions. An overall 30% and 35% reduction in muscle force of the SS and IS muscles, respectively, was observed compared with the left uninjured shoulder (P muscle groups. These results show that functional impairment of SS and IS muscles after chronic massive tendon tears could be attributed to the decrease in muscle force production during their repair on the greater tuberosity and, second, to the comparatively greater degeneration of their dorsal part. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  15. Massive gravity and Fierz-Pauli theory

    Energy Technology Data Exchange (ETDEWEB)

    Blasi, Alberto [Universita di Genova, Dipartimento di Fisica, Genova (Italy); Maggiore, Nicola [I.N.F.N.-Sezione di Genova, Genoa (Italy)

    2017-09-15

    Linearized gravity is considered as an ordinary gauge field theory. This implies the need for gauge fixing in order to have well-defined propagators. Only after having achieved this, the most general mass term is added. The aim of this paper is to study of the degrees of freedom of the gauge fixed theory of linearized gravity with mass term. The main result is that, even outside the usual Fierz-Pauli constraint on the mass term, it is possible to choose a gauge fixing belonging to the Landau class, which leads to a massive theory of gravity with the five degrees of freedom of a spin-2 massive particle. (orig.)

  16. Massive gravity and Fierz-Pauli theory

    International Nuclear Information System (INIS)

    Blasi, Alberto; Maggiore, Nicola

    2017-01-01

    Linearized gravity is considered as an ordinary gauge field theory. This implies the need for gauge fixing in order to have well-defined propagators. Only after having achieved this, the most general mass term is added. The aim of this paper is to study of the degrees of freedom of the gauge fixed theory of linearized gravity with mass term. The main result is that, even outside the usual Fierz-Pauli constraint on the mass term, it is possible to choose a gauge fixing belonging to the Landau class, which leads to a massive theory of gravity with the five degrees of freedom of a spin-2 massive particle. (orig.)

  17. SOUTHERN MASSIVE STARS AT HIGH ANGULAR RESOLUTION: OBSERVATIONAL CAMPAIGN AND COMPANION DETECTION

    Energy Technology Data Exchange (ETDEWEB)

    Sana, H. [European Space Agency/Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Le Bouquin, J.-B.; Duvert, G.; Zins, G. [Université Grenoble Alpes, IPAG, F-38000 Grenoble (France); Lacour, S.; Gauchet, L.; Pickel, D. [LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, Paris Sciences et Lettres, 5 Place Jules Janssen, F-92195 Meudon (France); Berger, J.-P. [European Southern Observatory, Schwarzschild-Str. 2, D-85748 Garching bei München (Germany); Norris, B. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Olofsson, J. [Max-Planck-Institut für Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Absil, O. [Département d' Astrophysique, Géophysique et Océanographie, Université de Liège, 17 Allée du Six Août, B-4000 Liège (Belgium); De Koter, A. [Astrophysical Institute Anton Pannekoek, Universiteit van Amsterdam, Science Park 904, 1098XH Amsterdam (Netherlands); Kratter, K. [JILA, 440 UCB, University of Colorado, Boulder, CO 80309-0440 (United States); Schnurr, O. [Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany); Zinnecker, H., E-mail: hsana@stsci.edu [Deutsches SOFIA Instituut, SOFIA Science Center, NASA Ames Research Center, Mail Stop N232-12, Moffett Field, CA 94035 (United States)

    2014-11-01

    Multiplicity is one of the most fundamental observable properties of massive O-type stars and offers a promising way to discriminate between massive star formation theories. Nevertheless, companions at separations between 1 and 100 milliarcsec (mas) remain mostly unknown due to intrinsic observational limitations. At a typical distance of 2 kpc, this corresponds to projected physical separations of 2-200 AU. The Southern MAssive Stars at High angular resolution survey (SMaSH+) was designed to fill this gap by providing the first systematic interferometric survey of Galactic massive stars. We observed 117 O-type stars with VLTI/PIONIER and 162 O-type stars with NACO/Sparse Aperture Masking (SAM), probing the separation ranges 1-45 and 30-250 mas and brightness contrasts of ΔH < 4 and ΔH < 5, respectively. Taking advantage of NACO's field of view, we further uniformly searched for visual companions in an 8'' radius down to ΔH = 8. This paper describes observations and data analysis, reports the discovery of almost 200 new companions in the separation range from 1 mas to 8'' and presents a catalog of detections, including the first resolved measurements of over a dozen known long-period spectroscopic binaries. Excluding known runaway stars for which no companions are detected, 96 objects in our main sample (δ < 0°; H < 7.5) were observed both with PIONIER and NACO/SAM. The fraction of these stars with at least one resolved companion within 200 mas is 0.53. Accounting for known but unresolved spectroscopic or eclipsing companions, the multiplicity fraction at separation ρ < 8'' increases to f {sub m} = 0.91 ± 0.03. The fraction of luminosity class V stars that have a bound companion reaches 100% at 30 mas while their average number of physically connected companions within 8'' is f {sub c} = 2.2 ± 0.3. This demonstrates that massive stars form nearly exclusively in multiple systems. The nine non-thermal radio

  18. On the spontaneous breakdown of massive gravities in 2 + 1 dimension

    International Nuclear Information System (INIS)

    Aragone, C.; Aria, P.J.; Andes Merida, Univ.; Khoudeir, A.

    1997-01-01

    This paper shows that locally Lorentz-invariant, third-order, topological massive gravity cannot be broken down either to the local diffeomorphism subgroup or to the rigid Poincare' group. On the other hand, the recently formulated, locally diffeomorphism-invariant, second order massive tradic (translational) Chern-Simons gravity breaks down on rigid Minkowski space to a double massive spin-two system. This flat double massive action is the uniform spin-two generalization of the Maxwell-Chern-Simons-Proca system which one is left with after U(1) Abelian gauge invariance breaks down in the presence of a sextic Higgs potential

  19. Luminous Infrared Galaxies. III. Multiple Merger, Extended Massive Star Formation, Galactic Wind, and Nuclear Inflow in NGC 3256

    Science.gov (United States)

    Lípari, S.; Díaz, R.; Taniguchi, Y.; Terlevich, R.; Dottori, H.; Carranza, G.

    2000-08-01

    We report detailed evidence for multiple merger, extended massive star formation, galactic wind, and circular/noncircular motions in the luminous infrared galaxy NGC 3256, based on observations of high-resolution imaging (Hubble Space Telescope, ESO NTT), and extensive spectroscopic data (more than 1000 spectra, collected at Estación Astrofísica de Bosque Alegre, Complejo Astronómico el Leoncito, Cerro Tololo InterAmerican Observatory, and IUE observatories). We find in a detailed morphological study (resolution ~15 pc) that the extended massive star formation process detected previously in NGC 3256 shows extended triple asymmetrical spiral arms (r~5 kpc), emanating from three different nuclei. The main optical nucleus shows a small spiral disk (r~500 pc), which is a continuation of the external one and reaches the very nucleus. The core shows blue elongated structure (50 pc×25 pc) and harbors a blue stellar cluster candidate (r~8 pc). We discuss this complex morphology in the framework of an extended massive star formation driven by a multiple merger process (models of Hernquist et al. and Taniguchi et al.). We study the kinematics of this system and present a detailed Hα velocity field for the central region (40''×40'' rmax~30''~5 kpc), with a spatial resolution of 1" and errors of +/-15 km s-1. The color and isovelocity maps show mainly (1) a kinematic center of circular motion with ``spider'' shape, located between the main optical nucleus and the close (5") mid-IR nucleus and (2) noncircular motions in the external parts. We obtained three ``sinusoidal rotation curves'' (from the Hα velocity field) around position angle (P.A.) ~55°, ~90°, and ~130°. In the main optical nucleus we found a clear ``outflow component'' associated with galactic winds plus an ``inflow radial motion.'' The outflow component was also detected in the central and external regions (rstandard models of photoionization, shocks, and starbursts). We present four detailed emission

  20. The nature of the central parsec of the Galaxy

    Science.gov (United States)

    Lacy, J. H.; Townes, C. H.; Hollenbach, D. J.

    1982-01-01

    Observations of infrared fine-structure line emission from compact clouds of ionized gas in the galactic center have been reported by Lacy et al (1979, 1980). These observations suggest the existence of a central black hole of nearly 3,000,000 solar masses and require mechanisms to generate, ionize, and dispose of the gas clouds. It is found that the best model to fulfill these requirements involves cloud generation through disruption of red giants by stellar collisions, ionization by a population of stars which is affected either by enhanced metal abundances or the death of the most massive stars, and gas disposal by star formation. Although the existence of a massive black hole cannot be ruled out, it would play no necessary role in this model and may cause the tidal disruption of stars at a rate such that their accretion into the black hole would produce more radiation than is observed.

  1. Massive and mass-less Yang-Mills and gravitational fields

    NARCIS (Netherlands)

    Veltman, M.J.G.; Dam, H. van

    1970-01-01

    Massive and mass-less Yang-Mills and gravitational fields are considered. It is found that there is a discrete difference between the zero-mass theories and the very small, but non-zero mass theories. In the case of gravitation, comparison of massive and mass-less theories with experiment, in

  2. Massive weight loss-induced mechanical plasticity in obese gait

    NARCIS (Netherlands)

    Hortobagyi, Tibor; Herring, Cortney; Pories, Walter J.; Rider, Patrick; DeVita, Paul

    2011-01-01

    Hortobagyi T, Herring C, Pories WJ, Rider P, DeVita P. Massive weight loss-induced mechanical plasticity in obese gait. J Appl Physiol 111: 1391-1399, 2011. First published August 18, 2011; doi:10.1152/japplphysiol.00291.2011.-We examined the hypothesis that metabolic surgery-induced massive weight

  3. Security and privacy in massively-multiplayer online games and social and corporate virtual worlds

    OpenAIRE

    Hogben, G.; Barosso, D.; Bartle, R.; Chazeran, C.; de Zwart, M.; Doumen, J.M.; Gorniak, S.; Kaźmierczak, M.; Kaskenmaa, M.; Benavente López, D.; Martin, A.; Naumann, I.; Reynolds, R.; Richardson, J; Rossow, C.

    2008-01-01

    2007 was the year of online gaming fraud - with malicious programs that specifically target online games and virtual worlds increasing by 145% and the emergence of over 30,000 new programs aimed at stealing online game passwords. Such malware is invariably aimed at the theft of virtual property accumulated in a user’s account and its sale for real money. With 217 million regular users of MMO/VWs (Massively Multiplayer Online Games and Virtual Worlds) and real-money sales of virtual objects es...

  4. Simulating nonlinear cosmological structure formation with massive neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Arka; Dalal, Neal, E-mail: abanerj6@illinois.edu, E-mail: dalaln@illinois.edu [Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801-3080 (United States)

    2016-11-01

    We present a new method for simulating cosmologies that contain massive particles with thermal free streaming motion, such as massive neutrinos or warm/hot dark matter. This method combines particle and fluid descriptions of the thermal species to eliminate the shot noise known to plague conventional N-body simulations. We describe this method in detail, along with results for a number of test cases to validate our method, and check its range of applicability. Using this method, we demonstrate that massive neutrinos can produce a significant scale-dependence in the large-scale biasing of deep voids in the matter field. We show that this scale-dependence may be quantitatively understood using an extremely simple spherical expansion model which reproduces the behavior of the void bias for different neutrino parameters.

  5. Simulating nonlinear cosmological structure formation with massive neutrinos

    International Nuclear Information System (INIS)

    Banerjee, Arka; Dalal, Neal

    2016-01-01

    We present a new method for simulating cosmologies that contain massive particles with thermal free streaming motion, such as massive neutrinos or warm/hot dark matter. This method combines particle and fluid descriptions of the thermal species to eliminate the shot noise known to plague conventional N-body simulations. We describe this method in detail, along with results for a number of test cases to validate our method, and check its range of applicability. Using this method, we demonstrate that massive neutrinos can produce a significant scale-dependence in the large-scale biasing of deep voids in the matter field. We show that this scale-dependence may be quantitatively understood using an extremely simple spherical expansion model which reproduces the behavior of the void bias for different neutrino parameters.

  6. Comparison between the fragmentation processes in central Pb + Ag and Pb + Au collisions

    International Nuclear Information System (INIS)

    Jouault, B.; Royer, G.; Sebille, F.; Haddad, F.; Lecolley, J.F.

    1996-01-01

    The fragmentation processes of a medium mass system and of a very massive one formed in central collisions are compared within the Landau-Vlasov model taking into account both the isospin dependence and the two-body residual interactions. The simulations predict the formation of a roughly ellipsoidal source in the central Pb + Ag reactions while, for the Pb + Au system, the fragmentation occurs from an hollow source, the configuration of which being intermediate between bubble-like and toroidal shapes. This difference shapes explain and allow to reproduce semi-quantitatively the two different profiles of the experimental kinetic energy spectra. (authors)

  7. Stochastic spin-one massive field

    International Nuclear Information System (INIS)

    Lim, S.C.

    1984-01-01

    Stochastic quantization schemes of Nelson and Parisi and Wu are applied to a spin-one massive field. Unlike the scalar case Nelson's stochastic spin-one massive field cannot be identified with the corresponding euclidean field even if the fourth component of the euclidean coordinate is taken as equal to the real physical time. In the Parisi-Wu quantization scheme the stochastic Proca vector field has a similar property as the scalar field; which has an asymptotically stationary part and a transient part. The large equal-time limit of the expectation values of the stochastic Proca field are equal to the expectation values of the corresponding euclidean field. In the Stueckelberg formalism the Parisi-Wu scheme gives rise to a stochastic vector field which differs from the massless gauge field in that the gauge cannot be fixed by the choice of boundary condition. (orig.)

  8. Minimal theory of massive gravity

    International Nuclear Information System (INIS)

    De Felice, Antonio; Mukohyama, Shinji

    2016-01-01

    We propose a new theory of massive gravity with only two propagating degrees of freedom. While the homogeneous and isotropic background cosmology and the tensor linear perturbations around it are described by exactly the same equations as those in the de Rham–Gabadadze–Tolley (dRGT) massive gravity, the scalar and vector gravitational degrees of freedom are absent in the new theory at the fully nonlinear level. Hence the new theory provides a stable nonlinear completion of the self-accelerating cosmological solution that was originally found in the dRGT theory. The cosmological solution in the other branch, often called the normal branch, is also rendered stable in the new theory and, for the first time, makes it possible to realize an effective equation-of-state parameter different from (either larger or smaller than) −1 without introducing any extra degrees of freedom.

  9. Generalized massive gravity in arbitrary dimensions and its Hamiltonian formulation

    International Nuclear Information System (INIS)

    Huang, Qing-Guo; Zhang, Ke-Chao; Zhou, Shuang-Yong

    2013-01-01

    We extend the four-dimensional de Rham-Gabadadze-Tolley (dRGT) massive gravity model to a general scalar massive-tensor theory in arbitrary dimensions, coupling a dRGT massive graviton to multiple scalars and allowing for generic kinetic and mass matrix mixing between the massive graviton and the scalars, and derive its Hamiltonian formulation and associated constraint system. When passing to the Hamiltonian formulation, two different sectors arise: a general sector and a special sector. Although obtained via different ways, there are two second class constraints in either of the two sectors, eliminating the BD ghost. However, for the special sector, there are still ghost instabilities except for the case of two dimensions. In particular, for the special sector with one scalar, there is a ''second BD ghost''

  10. Massive Black Hole Binaries: Dynamical Evolution and Observational Signatures

    Directory of Open Access Journals (Sweden)

    M. Dotti

    2012-01-01

    Full Text Available The study of the dynamical evolution of massive black hole pairs in mergers is crucial in the context of a hierarchical galaxy formation scenario. The timescales for the formation and the coalescence of black hole binaries are still poorly constrained, resulting in large uncertainties in the expected rate of massive black hole binaries detectable in the electromagnetic and gravitational wave spectra. Here, we review the current theoretical understanding of the black hole pairing in galaxy mergers, with a particular attention to recent developments and open issues. We conclude with a review of the expected observational signatures of massive binaries and of the candidates discussed in literature to date.

  11. QUALITY OF LIFE IN PATIENTS AFTER MASSIVE PULMONARY EMBOLISM

    Directory of Open Access Journals (Sweden)

    Dragan Kovačić

    2004-04-01

    Full Text Available Background. Pulmonary embolism is a disease, which has a 30% mortality if untreated, while an early diagnosis and treatment lowers it to 2–8%. Health related quality of life (HRQL of patients who survived massive pulmonary embolism is unknown in published literature. In our research we tried to apply experience of foreign experts in estimation of quality of life in some other diseases to the field of massive pulmonary embolism.Patients and methods. Eighteen patients with shock or hypotension due to massive pulmonary embolism, treated with thrombolysis, between July 1993 and November 2000, were prospectively included in the study. Control group included 18 gender and age matched persons. There were no significant differences regarding demographic data between the groups. The HRQL and aerobic capacity of patients and control group were tested with short questions and questionnaires (Veterans brief, self administered questionnaire (VSAQ, EuroQuality questionnaire (EQ, Living with heart failure questionnaire (LlhHF. With LlhHF physical (F-LlhHF and emotional (E-LlhHF HRQL was assessed at hospitalization and 12 months later.Results. One year after massive pulmonary embolism aerobic capacity (–9.5%, p < 0.017 and HRQL (EQ (–34.5%, F-LlhHF (–85.4%, E-LlhHF (–48.7% decreased in massive pulmonary embolism group compared to aerobic capacity 6 months before massive pulmonary embolism and HRQL. Heart rate before thrombolysis correlated with aerobic capacity (r = 0.627, p < 0.01, EQ (r = 0.479, p < 0.01 and F-LlhHF (r = 0.479, p = 0.04 1 year after massive pulmonary embolism. Total pulmonary resistance at 12 hours after start of treatment correlated with aerobic capacity at 1 year (r = 0.354, p < 0.01.With short question (»Did you need any help in everyday activities in last 2 weeks?« we successfully separated patients with decreased HRQL in EQ (74.3 ± 20.8 vs. 24.5 ± 20.7, p < 0.001 and F-LlhHF (21.7 ± 6.7 vs. 32.8 ± 4.3, p < 0.01, but we

  12. An actively accreting massive black hole in the dwarf starburst galaxy Henize 2-10.

    Science.gov (United States)

    Reines, Amy E; Sivakoff, Gregory R; Johnson, Kelsey E; Brogan, Crystal L

    2011-02-03

    Supermassive black holes are now thought to lie at the heart of every giant galaxy with a spheroidal component, including our own Milky Way. The birth and growth of the first 'seed' black holes in the earlier Universe, however, is observationally unconstrained and we are only beginning to piece together a scenario for their subsequent evolution. Here we report that the nearby dwarf starburst galaxy Henize 2-10 (refs 5 and 6) contains a compact radio source at the dynamical centre of the galaxy that is spatially coincident with a hard X-ray source. From these observations, we conclude that Henize 2-10 harbours an actively accreting central black hole with a mass of approximately one million solar masses. This nearby dwarf galaxy, simultaneously hosting a massive black hole and an extreme burst of star formation, is analogous in many ways to galaxies in the infant Universe during the early stages of black-hole growth and galaxy mass assembly. Our results confirm that nearby star-forming dwarf galaxies can indeed form massive black holes, and that by implication so can their primordial counterparts. Moreover, the lack of a substantial spheroidal component in Henize 2-10 indicates that supermassive black-hole growth may precede the build-up of galaxy spheroids.

  13. Collaborative Calibrated Peer Assessment in Massive Open Online Courses

    Science.gov (United States)

    Boudria, Asma; Lafifi, Yacine; Bordjiba, Yamina

    2018-01-01

    The free nature and open access courses in the Massive Open Online Courses (MOOC) allow the facilities of disseminating information for a large number of participants. However, the "massive" propriety can generate many pedagogical problems, such as the assessment of learners, which is considered as the major difficulty facing in the…

  14. Do massive compact objects without event horizon exist in infinite derivative gravity?

    Science.gov (United States)

    Koshelev, Alexey S.; Mazumdar, Anupam

    2017-10-01

    Einstein's general theory of relativity is plagued by cosmological and black-hole type singularities Recently, it has been shown that infinite derivative, ghost free, gravity can yield nonsingular cosmological and mini-black hole solutions. In particular, the theory possesses a mass-gap determined by the scale of new physics. This paper provides a plausible argument, not a no-go theorem, based on the Area-law of gravitational entropy that within infinite derivative, ghost free, gravity nonsingular compact objects in the static limit need not have horizons.

  15. Radiology in massive hemoptysis

    International Nuclear Information System (INIS)

    Marini, M.; Castro, J.M.; Gayol, A.; Aguilera, C.; Blanco, M.; Beraza, A.; Torres, J.

    1995-01-01

    We have reviewed our experience in diseases involving massive hemoptysis, systematizing the most common causes which include tuberculosis, bronchiectasis and cancer of the lung. Other less frequent causes, such as arteriovenous fistula, Aspergilloma, aneurysm, etc.; are also evaluated, and the most demonstrative images of each produced by the most precise imaging methods for their assessment are presented

  16. Massively Parallel Computing: A Sandia Perspective

    Energy Technology Data Exchange (ETDEWEB)

    Dosanjh, Sudip S.; Greenberg, David S.; Hendrickson, Bruce; Heroux, Michael A.; Plimpton, Steve J.; Tomkins, James L.; Womble, David E.

    1999-05-06

    The computing power available to scientists and engineers has increased dramatically in the past decade, due in part to progress in making massively parallel computing practical and available. The expectation for these machines has been great. The reality is that progress has been slower than expected. Nevertheless, massively parallel computing is beginning to realize its potential for enabling significant break-throughs in science and engineering. This paper provides a perspective on the state of the field, colored by the authors' experiences using large scale parallel machines at Sandia National Laboratories. We address trends in hardware, system software and algorithms, and we also offer our view of the forces shaping the parallel computing industry.

  17. A spin-4 analog of 3D massive gravity

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Kovacevic, Marija; Rosseel, Jan; Townsend, Paul K.; Yin, Yihao

    2011-01-01

    A sixth-order, but ghost-free, gauge-invariant action is found for a fourth-rank symmetric tensor potential in a three-dimensional (3D) Minkowski spacetime. It propagates two massive modes of spin 4 that are interchanged by parity and is thus a spin-4 analog of linearized 'new massive gravity'. Also

  18. Galaxy evolution. Quasar quartet embedded in giant nebula reveals rare massive structure in distant universe.

    Science.gov (United States)

    Hennawi, Joseph F; Prochaska, J Xavier; Cantalupo, Sebastiano; Arrigoni-Battaia, Fabrizio

    2015-05-15

    All galaxies once passed through a hyperluminous quasar phase powered by accretion onto a supermassive black hole. But because these episodes are brief, quasars are rare objects typically separated by cosmological distances. In a survey for Lyman-α emission at redshift z ≈ 2, we discovered a physical association of four quasars embedded in a giant nebula. Located within a substantial overdensity of galaxies, this system is probably the progenitor of a massive galaxy cluster. The chance probability of finding a quadruple quasar is estimated to be ∼10(-7), implying a physical connection between Lyman-α nebulae and the locations of rare protoclusters. Our findings imply that the most massive structures in the distant universe have a tremendous supply (≃10(11) solar masses) of cool dense (volume density ≃ 1 cm(-3)) gas, which is in conflict with current cosmological simulations. Copyright © 2015, American Association for the Advancement of Science.

  19. NEW APPROACHES TO EFFICIENCY OF MASSIVE ONLINE COURSE

    Directory of Open Access Journals (Sweden)

    Liubov S. Lysitsina

    2014-09-01

    Full Text Available This paper is focused on efficiency of e-learning, in general, and massive online course in programming and information technology, in particular. Several innovative approaches and scenarios have been proposed, developed, implemented and verified by the authors, including 1 a new approach to organize and use automatic immediate feedback that significantly helps a learner to verify developed code and increases an efficiency of learning, 2 a new approach to construct learning interfaces – it is based on “develop a code – get a result – validate a code” technique, 3 three scenarios of visualization and verification of developed code, 4 a new multi-stage approach to solve complex programming assignments, 5 a new implementation of “perfectionism” game mechanics in a massive online course. Overall, due to implementation of proposed and developed approaches, the efficiency of massive online course has been considerably increased, particularly 1 the additional 27.9 % of students were able to complete successfully “Web design and development using HTML5 and CSS3” massive online course at ITMO University, and 2 based on feedback from 5588 students a “perfectionism” game mechanics noticeably improves students’ involvement into course activities and retention factor.

  20. Photon emission from massive projectile impacts on solids.

    Science.gov (United States)

    Fernandez-Lima, F A; Pinnick, V T; Della-Negra, S; Schweikert, E A

    2011-01-01

    First evidence of photon emission from individual impacts of massive gold projectiles on solids for a number of projectile-target combinations is reported. Photon emission from individual impacts of massive Au(n) (+q) (1 ≤ n ≤ 400; q = 1-4) projectiles with impact energies in the range of 28-136 keV occurs in less than 10 ns after the projectile impact. Experimental observations show an increase in the photon yield from individual impacts with the projectile size and velocity. Concurrently with the photon emission, electron emission from the impact area has been observed below the kinetic emission threshold and under unlikely conditions for potential electron emission. We interpret the puzzling electron emission and correlated luminescence observation as evidence of the electronic excitation resulting from the high-energy density deposited by massive cluster projectiles during the impact.

  1. ALFIL: A Crowd Simulation Serious Game for Massive Evacuation Training and Awareness

    Science.gov (United States)

    García-García, César; Fernández-Robles, José Luis; Larios-Rosillo, Victor; Luga, Hervé

    2012-01-01

    This article presents the current development of a serious game for the simulation of massive evacuations. The purpose of this project is to promote self-protection through awareness of the procedures and different possible scenarios during the evacuation of a massive event. Sophisticated behaviors require massive computational power and it has…

  2. Transcatheter emboilization therapy of massive colonic bleeding

    International Nuclear Information System (INIS)

    Shin, G. H.; Oh, J. H.; Yoon, Y.

    1996-01-01

    To evaulate the efficacy and safety of emergent superselective transcatheter embolization for controlling massive colonic bleeding. Six of the seven patients who had symptom of massive gastrointestinal bleeding underwent emergent transcatheter embolization for control of the bleeding. Gastrointestinal bleeding in these patients was originated from various colonic diseases: rectal cancer(n=1), proctitis(n=1), benign ulcer(n=1), mucosal injury by ventriculoperitoneal shunt(n=1), and unknown(n=2). All patients except one with rectal cancer were critically ill. Superselective embolization were done by using Gelfoam particles and/or coils. The vessels embolized were ileocolic artery(n=1). superior rectal artery(n=2), inferior rectal artery (n=1), and middle and inferior rectal arteries(n=1). Hemostasis was successful immediately in all patients. Two underwnet surgery due to recurrent bleeding developed 3 days after the procedure(n=1) or in associalion with underlying rectal cancer(n=1). On surgical specimen of two cases, there was no mucosal ischemic change. Transcatheter embolization is a safe and effective treatment of method for the control of massive colonic bleeding

  3. Relativistic N-body simulations with massive neutrinos

    Science.gov (United States)

    Adamek, Julian; Durrer, Ruth; Kunz, Martin

    2017-11-01

    Some of the dark matter in the Universe is made up of massive neutrinos. Their impact on the formation of large scale structure can be used to determine their absolute mass scale from cosmology, but to this end accurate numerical simulations have to be developed. Due to their relativistic nature, neutrinos pose additional challenges when one tries to include them in N-body simulations that are traditionally based on Newtonian physics. Here we present the first numerical study of massive neutrinos that uses a fully relativistic approach. Our N-body code, gevolution, is based on a weak-field formulation of general relativity that naturally provides a self-consistent framework for relativistic particle species. This allows us to model neutrinos from first principles, without invoking any ad-hoc recipes. Our simulation suite comprises some of the largest neutrino simulations performed to date. We study the effect of massive neutrinos on the nonlinear power spectra and the halo mass function, focusing on the interesting mass range between 0.06 eV and 0.3 eV and including a case for an inverted mass hierarchy.

  4. IRAS colors of VLA identified objects in the galaxy

    International Nuclear Information System (INIS)

    Fich, M.; Terebey, S.

    1987-01-01

    Infrared Astronomy Satellite (IRAS) sources found within 4 degrees of l = 125 deg, b = 2 deg on the 3rd HCON 60 micron Sky Brightness Images were observed at the Very Large Array (VLA). Regions were to be identified where massive stars are forming by looking for small areas of radio continuum emissions. The IRAS sources could be divided into three groups by their IRAS 12 micron/25 micron and 60 micron/100 micron color. The group identified with star forming regions contained essentially all of the objects with extended radio emission. In all of these cases the extended radio emission showed a morphology consistent with the identification of these objects as HII regions. The conclusion drawn is that star formation regions can be distinguished from other objects by their infrared colors

  5. Satisfying the Einstein-Podolsky-Rosen criterion with massive particles

    Science.gov (United States)

    Peise, J.; Kruse, I.; Lange, K.; Lücke, B.; Pezzè, L.; Arlt, J.; Ertmer, W.; Hammerer, K.; Santos, L.; Smerzi, A.; Klempt, C.

    2016-03-01

    In 1935, Einstein, Podolsky and Rosen (EPR) questioned the completeness of quantum mechanics by devising a quantum state of two massive particles with maximally correlated space and momentum coordinates. The EPR criterion qualifies such continuous-variable entangled states, as shown successfully with light fields. Here, we report on the production of massive particles which meet the EPR criterion for continuous phase/amplitude variables. The created quantum state of ultracold atoms shows an EPR parameter of 0.18(3), which is 2.4 standard deviations below the threshold of 1/4. Our state presents a resource for tests of quantum nonlocality with massive particles and a wide variety of applications in the field of continuous-variable quantum information and metrology.

  6. Minimal theory of massive gravity

    Directory of Open Access Journals (Sweden)

    Antonio De Felice

    2016-01-01

    Full Text Available We propose a new theory of massive gravity with only two propagating degrees of freedom. While the homogeneous and isotropic background cosmology and the tensor linear perturbations around it are described by exactly the same equations as those in the de Rham–Gabadadze–Tolley (dRGT massive gravity, the scalar and vector gravitational degrees of freedom are absent in the new theory at the fully nonlinear level. Hence the new theory provides a stable nonlinear completion of the self-accelerating cosmological solution that was originally found in the dRGT theory. The cosmological solution in the other branch, often called the normal branch, is also rendered stable in the new theory and, for the first time, makes it possible to realize an effective equation-of-state parameter different from (either larger or smaller than −1 without introducing any extra degrees of freedom.

  7. CENTRAL BANKING IN THE NEW ERA

    Directory of Open Access Journals (Sweden)

    Bilal Bagis

    2017-12-01

    Full Text Available This paper analyzes the evolution of central banking, and in particular the American experience of central banking. It provides projections for the future of central banking in the new era of post 2008. The paper initially demonstrates recent improvements in the financial and banking sectors, regulations and different measures of monetary and financial rules both in the USA and the rest of the advanced economies. Then, it claims institutions, such as central banks, will gain new objectives and more significance in this new era and thus will be given new roles, over time and along with the improvements and deepening in the financial system. The paper argues centuries long central bank evolution is not complete yet and that more objectives should be expected to come forward. In that line, there is need for a shift in the conventional policy measures. New trends in central banking such as the helicopter money, popular nominal GDP targeting regime and the retro developmental central banking are all critically analyzed. The paper provides a breakdown of financial development and central banking activities in a historical context and provides a rationale and a new basis for possible future innovations.

  8. Object-oriented programming with gradual abstraction

    DEFF Research Database (Denmark)

    Nørmark, Kurt; Thomsen, Lone Leth; Thomsen, Bent

    2013-01-01

    We describe an experimental object-oriented programming language, ASL2, that supports program development by means of a series of abstraction steps. The language allows immediate object construction, and it is possible to use the constructed objects for concrete problem solving tasks. Classes...... restrictive. As a central mechanism, weakly classified objects are allowed to borrow methods from each other. ASL2 supports class generalization, as a counterpart to class specialization and inheritance in mainstream object-oriented programming languages. The final abstraction step discussed in this paper...

  9. AVL and Monitoring for Massive Traffic Control System over DDS

    Directory of Open Access Journals (Sweden)

    Basem Almadani

    2015-01-01

    Full Text Available This paper proposes a real-time Automatic Vehicle Location (AVL and monitoring system for traffic control of pilgrims coming towards the city of Makkah in Saudi Arabia based on Data Distribution Service (DDS specified by the Object Management Group (OMG. DDS based middleware employs Real-Time Publish/Subscribe (RTPS protocol that implements many-to-many communication paradigm suitable in massive traffic control applications. Using this middleware approach, we are able to locate and track huge number of mobile vehicles and identify all passengers in real-time who are coming to perform annual Hajj. For validation of our proposed framework, various performance matrices are examined over WLAN using DDS. Results show that DDS based middleware can meet real-time requirements in large-scale AVL environment.

  10. Objective Analysis of Performance of Activities of Daily Living in People With Central Field Loss.

    Science.gov (United States)

    Pardhan, Shahina; Latham, Keziah; Tabrett, Daryl; Timmis, Matthew A

    2015-11-01

    People with central visual field loss (CFL) adopt various strategies to complete activities of daily living (ADL). Using objective movement analysis, we compared how three ADLs were completed by people with CFL compared with age-matched, visually healthy individuals. Fourteen participants with CFL (age 81 ± 10 years) and 10 age-matched, visually healthy (age 75 ± 5 years) participated. Three ADLs were assessed: pick up food from a plate, pour liquid from a bottle, and insert a key in a lock. Participants with CFL completed each ADL habitually (as they would in their home). Data were compared with visually healthy participants who were asked to complete the tasks as they would normally, but under specified experimental conditions. Movement kinematics were compared using three-dimension motion analysis (Vicon). Visual functions (distance and near acuities, contrast sensitivity, visual fields) were recorded. All CFL participants were able to complete each ADL. However, participants with CFL demonstrated significantly (P approach. Various kinematic indices correlated significantly to visual function parameters including visual acuity and midperipheral visual field loss.

  11. Diagnosis and Management of Combined Central Diabetes Insipidus and Cerebral Salt Wasting Syndrome After Traumatic Brain Injury.

    Science.gov (United States)

    Wu, Xuehai; Zhou, Xiaolan; Gao, Liang; Wu, Xing; Fei, Li; Mao, Ying; Hu, Jin; Zhou, Liangfu

    2016-04-01

    Combined central diabetes insipidus and cerebral salt wasting syndrome after traumatic brain injury (TBI) is rare, is characterized by massive polyuria leading to severe water and electrolyte disturbances, and usually is associated with very high mortality mainly as a result of delayed diagnosis and improper management. We retrospectively reviewed the clinical presentation, management, and outcomes of 11 patients who developed combined central diabetes insipidus and cerebral salt wasting syndrome after traumatic brain injury to define distinctive features for timely diagnosis and proper management. The most typical clinical presentation was massive polyuria (10,000 mL/24 hours or >1000 mL/hour) refractory to vasopressin alone but responsive to vasopressin plus cortisone acetate. Other characteristic presentations included low central venous pressure, high brain natriuretic peptide precursor level without cardiac dysfunction, high 24-hour urine sodium excretion and hypovolemia, and much higher urine than serum osmolarity; normal serum sodium level and urine specific gravity can also be present. Timely and adequate infusion of sodium chloride was key in treatment. Of 11 patients, 5 had a good prognosis 3 months later (Extended Glasgow Outcome Scale score ≥6), 1 had an Extended Glasgow Outcome Scale score of 4, 2 died in the hospital of brain hernia, and 3 developed a vegetative state. For combined diabetes insipidus and cerebral salt wasting syndrome after traumatic brain injury, massive polyuria is a major typical presentation, and intensive monitoring of fluid and sodium status is key for timely diagnosis. To achieve a favorable outcome, proper sodium chloride supplementation and cortisone acetate and vasopressin coadministration are key. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Multimodality imaging findings of massive ovarian edema in children

    Energy Technology Data Exchange (ETDEWEB)

    Dahmoush, Hisham [Stanford University Medical Center, Department of Radiology, Neuroradiology Division, Stanford, CA (United States); Anupindi, Sudha A.; Chauvin, Nancy A. [University of Pennsylvania, The Children' s Hospital of Philadelphia, Department of Radiology, Perelman School of Medicine, Philadelphia, PA (United States); Pawel, Bruce R. [University of Pennsylvania, The Children' s Hospital of Philadelphia, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, Philadelphia, PA (United States)

    2017-05-15

    Massive ovarian edema is a rare benign condition that predominantly affects childbearing women as well as preadolescent girls. It is thought to result from intermittent or partial torsion of the ovary compromising the venous and lymphatic drainage but with preserved arterial supply. The clinical features of massive ovarian edema are nonspecific and can simulate tumors, leading to unnecessary oophorectomy. To demonstrate imaging features that should alert radiologists to consider the diagnosis of massive ovarian edema preoperatively so that fertility-sparing surgery may be considered. We identified five girls diagnosed with massive ovarian edema at pathology. Presenting symptoms, sidedness, imaging appearance, preoperative diagnosis, and operative and histopathological findings were reviewed. Age range was 9.6-14.3 years (mean age: 12.5 years). Common imaging findings included ovarian enlargement with edema of the stroma, peripherally placed follicles, isointense signal on T1-W MRI and markedly hyperintense signal on T2-W MRI, preservation of color Doppler flow by US, and CT Hounsfield units below 40. The uterus was deviated to the affected side in all patients. Two of the five patients had small to moderate amounts of free pelvic fluid. Mean ovarian volume on imaging was 560 mL (range: 108-1,361 mL). While the clinical presentation of massive ovarian edema is nonspecific, an enlarged ovary with stromal edema, peripherally placed follicles and preservation of blood flow may be suggestive and wedge biopsy should be considered intraoperatively to avoid unnecessary removal of the ovary. (orig.)

  13. Spontaneous Lorentz and diffeomorphism violation, massive modes, and gravity

    International Nuclear Information System (INIS)

    Bluhm, Robert; Fung Shuhong; Kostelecky, V. Alan

    2008-01-01

    Theories with spontaneous local Lorentz and diffeomorphism violation contain massless Nambu-Goldstone modes, which arise as field excitations in the minimum of the symmetry-breaking potential. If the shape of the potential also allows excitations above the minimum, then an alternative gravitational Higgs mechanism can occur in which massive modes involving the metric appear. The origin and basic properties of the massive modes are addressed in the general context involving an arbitrary tensor vacuum value. Special attention is given to the case of bumblebee models, which are gravitationally coupled vector theories with spontaneous local Lorentz and diffeomorphism violation. Mode expansions are presented in both local and spacetime frames, revealing the Nambu-Goldstone and massive modes via decomposition of the metric and bumblebee fields, and the associated symmetry properties and gauge fixing are discussed. The class of bumblebee models with kinetic terms of the Maxwell form is used as a focus for more detailed study. The nature of the associated conservation laws and the interpretation as a candidate alternative to Einstein-Maxwell theory are investigated. Explicit examples involving smooth and Lagrange-multiplier potentials are studied to illustrate features of the massive modes, including their origin, nature, dispersion laws, and effects on gravitational interactions. In the weak static limit, the massive mode and Lagrange-multiplier fields are found to modify the Newton and Coulomb potentials. The nature and implications of these modifications are examined.

  14. Multimodality imaging findings of massive ovarian edema in children

    International Nuclear Information System (INIS)

    Dahmoush, Hisham; Anupindi, Sudha A.; Chauvin, Nancy A.; Pawel, Bruce R.

    2017-01-01

    Massive ovarian edema is a rare benign condition that predominantly affects childbearing women as well as preadolescent girls. It is thought to result from intermittent or partial torsion of the ovary compromising the venous and lymphatic drainage but with preserved arterial supply. The clinical features of massive ovarian edema are nonspecific and can simulate tumors, leading to unnecessary oophorectomy. To demonstrate imaging features that should alert radiologists to consider the diagnosis of massive ovarian edema preoperatively so that fertility-sparing surgery may be considered. We identified five girls diagnosed with massive ovarian edema at pathology. Presenting symptoms, sidedness, imaging appearance, preoperative diagnosis, and operative and histopathological findings were reviewed. Age range was 9.6-14.3 years (mean age: 12.5 years). Common imaging findings included ovarian enlargement with edema of the stroma, peripherally placed follicles, isointense signal on T1-W MRI and markedly hyperintense signal on T2-W MRI, preservation of color Doppler flow by US, and CT Hounsfield units below 40. The uterus was deviated to the affected side in all patients. Two of the five patients had small to moderate amounts of free pelvic fluid. Mean ovarian volume on imaging was 560 mL (range: 108-1,361 mL). While the clinical presentation of massive ovarian edema is nonspecific, an enlarged ovary with stromal edema, peripherally placed follicles and preservation of blood flow may be suggestive and wedge biopsy should be considered intraoperatively to avoid unnecessary removal of the ovary. (orig.)

  15. A Massive-born Neutron Star with a Massive White Dwarf Companion

    Energy Technology Data Exchange (ETDEWEB)

    Cognard, Ismaël; Guillemot, Lucas; Theureau, Gilles [Laboratoire de Physique et Chimie de l’Environnement et de l’Espace, Université d’Orléans/CNRS, F-45071 Orléans Cedex 02 (France); Freire, Paulo C. C. [Station de radioastronomie de Nançay, Observatoire de Paris, CNRS/INSU, F-18330 Nançay (France); Tauris, Thomas M.; Wex, Norbert; Graikou, Eleni; Kramer, Michael; Desvignes, Gregory; Lazarus, Patrick [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Stappers, Benjamin; Lyne, Andrew G. [Jodrell Bank Center for Astrophysics, School of Physics and Astronomy, The University of Manchester, M13 9PL (United Kingdom); Bassa, Cees [ASTRON, The Netherlands Institute for Radioastronomy, Postbus 2, 7900 AA, Dwingeloo (Netherlands)

    2017-08-01

    We report on the results of a 4 year timing campaign of PSR J2222−0137, a 2.44 day binary pulsar with a massive white dwarf (WD) companion, with the Nançay, Effelsberg, and Lovell radio telescopes. Using the Shapiro delay for this system, we find a pulsar mass m {sub p} = 1.76 ± 0.06 M {sub ⊙} and a WD mass m {sub c} = 1.293 ± 0.025 M {sub ⊙}. We also measure the rate of advance of periastron for this system, which is marginally consistent with the general relativity prediction for these masses. The short lifetime of the massive WD progenitor star led to a rapid X-ray binary phase with little (< 10{sup −2} M {sub ⊙}) mass accretion onto the neutron star; hence, the current pulsar mass is, within uncertainties, its birth mass, which is the largest measured to date. We discuss the discrepancy with previous mass measurements for this system; we conclude that the measurements presented here are likely to be more accurate. Finally, we highlight the usefulness of this system for testing alternative theories of gravity by tightly constraining the presence of dipolar radiation. This is of particular importance for certain aspects of strong-field gravity, like spontaneous scalarization, since the mass of PSR J2222−0137 puts that system into a poorly tested parameter range.

  16. ARTS - adaptive runtime system for massively parallel systems. Final report; ARTS - optimale Ausfuehrungsunterstuetzung fuer komplexe Anwendungen auf massiv parallelen Systemen. Teilprojekt: Parallele Stroemungsmechanik. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Gentzsch, W.; Ferstl, F.; Paap, H.G.; Riedel, E.

    1998-03-20

    In the ARTS project, system software has been developed to support smog and fluid dynamic applications on massively parallel systems. The aim is to implement and test specific software structures within an adaptive run-time system to separate the parallel core algorithms of the applications from the platform independent runtime aspects. Only slight modifications is existing Fortran and C code are necessary to integrate the application code into the new object oriented parallel integrated ARTS framework. The OO-design offers easy control, re-use and adaptation of the system services, resulting in a dramatic decrease in development time of the application and in ease of maintainability of the application software in the future. (orig.) [Deutsch] Im Projekt ARTS wird Basissoftware zur Unterstuetzung von Anwendungen aus den Bereichen Smoganalyse und Stroemungsmechanik auf massiv parallelen Systemen entwickelt und optimiert. Im Vordergrund steht die Erprobung geeigneter Strukturen, um systemnahe Funktionalitaeten in einer Laufzeitumgebung anzusiedeln und dadurch die parallelen Kernalgorithmen der Anwendungsprogramme von den plattformunabhaengigen Laufzeitaspekten zu trennen. Es handelt sich dabei um herkoemmlich strukturierten Fortran-Code, der unter minimalen Aenderungen auch weiterhin nutzbar sein muss, sowie um objektbasiert entworfenen C-Code, der die volle Funktionalitaet der ARTS-Plattform ausnutzen kann. Ein objektorientiertes Design erlaubt eine einfache Kontrolle, Wiederverwendung und Adaption der vom System vorgegebenen Basisdienste. Daraus resultiert ein deutlich reduzierter Entwicklungs- und Laufzeitaufwand fuer die Anwendung. ARTS schafft eine integrierende Plattform, die moderne Technologien aus dem Bereich objektorientierter Laufzeitsysteme mit praxisrelevanten Anforderungen aus dem Bereich des wissenschaftlichen Hoechstleistungsrechnens kombiniert. (orig.)

  17. Are the good functional results from arthroscopic repair of massive rotator cuff injuries maintained over the long term?

    Directory of Open Access Journals (Sweden)

    Alberto Naoki Miyazaki

    2016-02-01

    Full Text Available ABSTRACT OBJECTIVE: To evaluate whether the good and excellent functional results from arthroscopic repair of massive rotator cuff tears are maintained over the long term. METHODS: From the sample of the study conducted by our group in 2006, in which we evaluated the functional results from arthroscopic repair of massive rotator cuff tears, 35 patients were reassessed, 8 years after the first evaluation. The inclusion criteria were that these patients with massive rotator cuff tears operated by means of an arthroscopic technique, who participated in the previous study and achieved good or excellent outcomes according to the UCLA criteria. Patients whose results were not good or excellent in the first evaluation according to the UCLA criteria were excluded. RESULTS: Among the 35 patients reassessed, 91% of them continued to present good and excellent results (40% excellent and 51% good, while 3% presented fair results and 6% poor results. The time interval between the first and second evaluations was 8 years and the minimum length of follow-up since the immediate postoperative period was 9 years (range: 9-17 years, with an average of 11.4 years. CONCLUSION: The good and excellent results from arthroscopic repair of massive rotator cuff tears were mostly maintained (91%, with the same level of function and satisfaction, even though 8 years had passed since the first assessment, with a follow-up period averaging 11.4 years.

  18. The formation and gravitational-wave detection of massive stellar black hole binaries

    International Nuclear Information System (INIS)

    Belczynski, Krzysztof; Walczak, Marek; Buonanno, Alessandra; Cantiello, Matteo; Fryer, Chris L.; Holz, Daniel E.; Mandel, Ilya; Miller, M. Coleman

    2014-01-01

    If binaries consisting of two ∼100 M ☉ black holes exist, they would serve as extraordinarily powerful gravitational-wave sources, detectable to redshifts of z ∼ 2 with the advanced LIGO/Virgo ground-based detectors. Large uncertainties about the evolution of massive stars preclude definitive rate predictions for mergers of these massive black holes. We show that rates as high as hundreds of detections per year, or as low as no detections whatsoever, are both possible. It was thought that the only way to produce these massive binaries was via dynamical interactions in dense stellar systems. This view has been challenged by the recent discovery of several ≳ 150 M ☉ stars in the R136 region of the Large Magellanic Cloud. Current models predict that when stars of this mass leave the main sequence, their expansion is insufficient to allow common envelope evolution to efficiently reduce the orbital separation. The resulting black hole-black hole binary remains too wide to be able to coalesce within a Hubble time. If this assessment is correct, isolated very massive binaries do not evolve to be gravitational-wave sources. However, other formation channels exist. For example, the high multiplicity of massive stars, and their common formation in relatively dense stellar associations, opens up dynamical channels for massive black hole mergers (e.g., via Kozai cycles or repeated binary-single interactions). We identify key physical factors that shape the population of very massive black hole-black hole binaries. Advanced gravitational-wave detectors will provide important constraints on the formation and evolution of very massive stars.

  19. Open Issues in Object-Oriented Programming

    DEFF Research Database (Denmark)

    Madsen, Ole Lehrmann

    1995-01-01

    We discuss a number of open issues within object-oriented programming. The central mechanisms of object-oriented programming appeared with Simula, developed more than 30 years ago; these include class, subclass, virtual function, active object and the first application framework, Class Simulation....... The core parts of object-oriented programming should be well understood, but there are still a large number of issues where there is no consensus. The term object-orientation has been applied to many subjects, such as analysis, design implementation, data modeling in databases, and distribution...

  20. f (T) Non-linear Massive Gravity and the Cosmic Acceleration

    International Nuclear Information System (INIS)

    Wu You; Chen Zu-Cheng; Wei Hao; Wang Jia-Xin

    2015-01-01

    Inspired by the f (R) non-linear massive gravity, we propose a new kind of modified gravity model, namely f (T) non-linear massive gravity, by adding the dRGT mass term reformulated in the vierbein formalism, to the f (T) theory. We then investigate the cosmological evolution of f (T) massive gravity, and constrain it by using the latest observational data. We find that it slightly favors a crossing of the phantom divide line from the quintessence-like phase (w_d_e > −1) to the phantom-like one (w_d_e < −1) as redshift decreases. (paper)

  1. Deployment and Implementation Strategies for Massive MIMO in 5G

    DEFF Research Database (Denmark)

    Panzner, Berthold; Zirwas, Wolfgang; Dierks, Stefan

    2015-01-01

    for 5G is a successful and cost-efficient integration in the overall network concept. This work highlights deployment and implementation strategies for massive MIMO in the context of 5G indoor small cell scenarios. Different massive MIMO deployment scenarios are analyzed for a standard 3GPP indoor...... to spatial streams is varied stepwise from equality to a factor of ten. For implementation of massive MIMO in 5G networks trends in beamforming techniques, mutually coupled subarrays, over the calibration procedure and estimated ADC performance in 2020 time-frame are discussed. Based on the debate the paper...

  2. A dynamical theory for linearized massive superspin 3/2

    International Nuclear Information System (INIS)

    Gates, James S. Jr.; Koutrolikos, Konstantinos

    2014-01-01

    We present a new theory of free massive superspin Y=3/2 irreducible representation of the 4D, N=1 Super-Poincaré group, which has linearized non-minimal supergravity (superhelicity Y=3/2) as it’s massless limit. The new results will illuminate the underlying structure of auxiliary superfields required for the description of higher massive superspin systems

  3. Cleaning Massive Sonar Point Clouds

    DEFF Research Database (Denmark)

    Arge, Lars Allan; Larsen, Kasper Green; Mølhave, Thomas

    2010-01-01

    We consider the problem of automatically cleaning massive sonar data point clouds, that is, the problem of automatically removing noisy points that for example appear as a result of scans of (shoals of) fish, multiple reflections, scanner self-reflections, refraction in gas bubbles, and so on. We...

  4. Classical and quantum cosmology of minimal massive bigravity

    Energy Technology Data Exchange (ETDEWEB)

    Darabi, F., E-mail: f.darabi@azaruniv.edu; Mousavi, M., E-mail: mousavi@azaruniv.edu

    2016-10-10

    In a Friedmann–Robertson–Walker (FRW) space–time background we study the classical cosmological models in the context of recently proposed theory of nonlinear minimal massive bigravity. We show that in the presence of perfect fluid the classical field equations acquire contribution from the massive graviton as a cosmological term which is positive or negative depending on the dynamical competition between two scale factors of bigravity metrics. We obtain the classical field equations for flat and open universes in the ordinary and Schutz representation of perfect fluid. Focusing on the Schutz representation for flat universe, we find classical solutions exhibiting singularities at early universe with vacuum equation of state. Then, in the Schutz representation, we study the quantum cosmology for flat universe and derive the Schrodinger–Wheeler–DeWitt equation. We find its exact and wave packet solutions and discuss on their properties to show that the initial singularity in the classical solutions can be avoided by quantum cosmology. Similar to the study of Hartle–Hawking no-boundary proposal in the quantum cosmology of de Rham, Gabadadze and Tolley (dRGT) massive gravity, it turns out that the mass of graviton predicted by quantum cosmology of the minimal massive bigravity is large at early universe. This is in agreement with the fact that at early universe the cosmological constant should be large.

  5. Classical and quantum cosmology of minimal massive bigravity

    International Nuclear Information System (INIS)

    Darabi, F.; Mousavi, M.

    2016-01-01

    In a Friedmann–Robertson–Walker (FRW) space–time background we study the classical cosmological models in the context of recently proposed theory of nonlinear minimal massive bigravity. We show that in the presence of perfect fluid the classical field equations acquire contribution from the massive graviton as a cosmological term which is positive or negative depending on the dynamical competition between two scale factors of bigravity metrics. We obtain the classical field equations for flat and open universes in the ordinary and Schutz representation of perfect fluid. Focusing on the Schutz representation for flat universe, we find classical solutions exhibiting singularities at early universe with vacuum equation of state. Then, in the Schutz representation, we study the quantum cosmology for flat universe and derive the Schrodinger–Wheeler–DeWitt equation. We find its exact and wave packet solutions and discuss on their properties to show that the initial singularity in the classical solutions can be avoided by quantum cosmology. Similar to the study of Hartle–Hawking no-boundary proposal in the quantum cosmology of de Rham, Gabadadze and Tolley (dRGT) massive gravity, it turns out that the mass of graviton predicted by quantum cosmology of the minimal massive bigravity is large at early universe. This is in agreement with the fact that at early universe the cosmological constant should be large.

  6. Cosmology in general massive gravity theories

    International Nuclear Information System (INIS)

    Comelli, D.; Nesti, F.; Pilo, L.

    2014-01-01

    We study the cosmological FRW flat solutions generated in general massive gravity theories. Such a model are obtained adding to the Einstein General Relativity action a peculiar non derivative potentials, function of the metric components, that induce the propagation of five gravitational degrees of freedom. This large class of theories includes both the case with a residual Lorentz invariance as well as the case with rotational invariance only. It turns out that the Lorentz-breaking case is selected as the only possibility. Moreover it turns out that that perturbations around strict Minkowski or dS space are strongly coupled. The upshot is that even though dark energy can be simply accounted by massive gravity modifications, its equation of state w eff has to deviate from -1. Indeed, there is an explicit relation between the strong coupling scale of perturbations and the deviation of w eff from -1. Taking into account current limits on w eff and submillimiter tests of the Newton's law as a limit on the possible strong coupling scale, we find that it is still possible to have a weakly coupled theory in a quasi dS background. Future experimental improvements on short distance tests of the Newton's law may be used to tighten the deviation of w eff form -1 in a weakly coupled massive gravity theory

  7. Proliferation of massive destruction weapons: fantasy or reality?

    International Nuclear Information System (INIS)

    Duval, M.

    2001-01-01

    This article evaluates the threat of massive destruction weapons (nuclear, chemical, biological) for Europe and recalls the existing safeguards against the different forms of nuclear proliferation: legal (non-proliferation treaty (NPT), comprehensive nuclear test ban treaty (CTBT), fissile material cut off treaty (FMCT) etc..), technical (fabrication of fissile materials, delays). However, all these safeguards can be overcome as proven by the activities of some countries. The situation of proliferation for the other type of massive destruction weapons is presented too. (J.S.)

  8. Kundt solutions of minimal massive 3D gravity

    Science.gov (United States)

    Deger, Nihat Sadik; Sarıoǧlu, Ã.-zgür

    2015-11-01

    We construct Kundt solutions of minimal massive gravity theory and show that, similar to topologically massive gravity (TMG), most of them are constant scalar invariant (CSI) spacetimes that correspond to deformations of round and warped (A)dS. We also find an explicit non-CSI Kundt solution at the merger point. Finally, we give their algebraic classification with respect to the traceless Ricci tensor (Segre classification) and show that their Segre types match with the types of their counterparts in TMG.

  9. Complexity growth in minimal massive 3D gravity

    Science.gov (United States)

    Qaemmaqami, Mohammad M.

    2018-01-01

    We study the complexity growth by using "complexity =action " (CA) proposal in the minimal massive 3D gravity (MMG) model which is proposed for resolving the bulk-boundary clash problem of topologically massive gravity (TMG). We observe that the rate of the complexity growth for Banados-Teitelboim-Zanelli (BTZ) black hole saturates the proposed bound by physical mass of the BTZ black hole in the MMG model, when the angular momentum parameter and the inner horizon of black hole goes to zero.

  10. Volcanogenic massive sulfide occurrence model: Chapter C in Mineral deposit models for resource assessment

    Science.gov (United States)

    Shanks, W.C. Pat; Koski, Randolph A.; Mosier, Dan L.; Schulz, Klaus J.; Morgan, Lisa A.; Slack, John F.; Ridley, W. Ian; Dusel-Bacon, Cynthia; Seal, Robert R.; Piatak, Nadine M.; Shanks, W.C. Pat; Thurston, Roland

    2012-01-01

    Volcanogenic massive sulfide deposits, also known as volcanic-hosted massive sulfide, volcanic-associated massive sulfide, or seafloor massive sulfide deposits, are important sources of copper, zinc, lead, gold, and silver (Cu, Zn, Pb, Au, and Ag). These deposits form at or near the seafloor where circulating hydrothermal fluids driven by magmatic heat are quenched through mixing with bottom waters or porewaters in near-seafloor lithologies. Massive sulfide lenses vary widely in shape and size and may be podlike or sheetlike. They are generally stratiform and may occur as multiple lenses.

  11. Massive Neurofibroma of the Breast

    African Journals Online (AJOL)

    Valued eMachines Customer

    Neurofibromas are benign nerve sheath tumors that are extremely rare in the breast. We report a massive ... plexiform breast neurofibromas may transform into a malignant peripheral nerve sheath tumor1. We present a case .... Breast neurofibroma. http://www.breast-cancer.ca/type/breast-neurofibroma.htm. August 2011. 2.

  12. SUPERDENSE MASSIVE GALAXIES IN WINGS LOCAL CLUSTERS

    International Nuclear Information System (INIS)

    Valentinuzzi, T.; D'Onofrio, M.; Fritz, J.; Poggianti, B. M.; Bettoni, D.; Fasano, G.; Moretti, A.; Omizzolo, A.; Varela, J.; Cava, A.; Couch, W. J.; Dressler, A.; Moles, M.; Kjaergaard, P.; Vanzella, E.

    2010-01-01

    Massive quiescent galaxies at z > 1 have been found to have small physical sizes, and hence to be superdense. Several mechanisms, including minor mergers, have been proposed for increasing galaxy sizes from high- to low-z. We search for superdense massive galaxies in the WIde-field Nearby Galaxy-cluster Survey (WINGS) of X-ray selected galaxy clusters at 0.04 10 M sun , are mostly S0 galaxies, have a median effective radius (R e ) = 1.61 ± 0.29 kpc, a median Sersic index (n) = 3.0 ± 0.6, and very old stellar populations with a median mass-weighted age of 12.1 ± 1.3 Gyr. We calculate a number density of 2.9 x 10 -2 Mpc -3 for superdense galaxies in local clusters, and a hard lower limit of 1.3 x 10 -5 Mpc -3 in the whole comoving volume between z = 0.04 and z = 0.07. We find a relation between mass, effective radius, and luminosity-weighted age in our cluster galaxies, which can mimic the claimed evolution of the radius with redshift, if not properly taken into account. We compare our data with spectroscopic high-z surveys and find that-when stellar masses are considered-there is consistency with the local WINGS galaxy sizes out to z ∼ 2, while a discrepancy of a factor of 3 exists with the only spectroscopic z > 2 study. In contrast, there is strong evidence for a large evolution in radius for the most massive galaxies with M * > 4 x 10 11 M sun compared to similarly massive galaxies in WINGS, i.e., the brightest cluster galaxies.

  13. The Massive Yang-Mills Model and Diffractive Scattering

    CERN Document Server

    Forshaw, J R; Parrinello, C

    1999-01-01

    We argue that the massive Yang-Mills model of Kunimasa and Goto, Slavnov, and Cornwall, in which massive gauge vector bosons are introduced in a gauge-invariant way without resorting to the Higgs mechanism, may be useful for studying diffractive scattering of strongly interacting particles. With this motivation, we perform in this model explicit calculations of S-matrix elements between quark states, at tree level, one loop, and two loops, and discuss issues of renormalisability and unitarity. In particular, it is shown that the S-matrix element for quark scattering is renormalisable at one-loop order and is only logarithmically non-renormalisable at two loops. The discrepancies in the ultraviolet regime between the one-loop predictions of this model and those of massless QCD are discussed in detail. In addition, some of the similarities and differences between the massive Yang-Mills model and theories with a Higgs mechanism are analysed at the level of the S-matrix. As an elementary application of the model ...

  14. Massive fields as systematics for single field inflation

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Hongliang; Wang, Yi, E-mail: hjiangag@connect.ust.hk, E-mail: phyw@ust.hk [Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)

    2017-06-01

    During inflation, massive fields can contribute to the power spectrum of curvature perturbation via a dimension-5 operator. This contribution can be considered as a bias for the program of using n {sub s} and r to select inflation models. Even the dimension-5 operator is suppressed by Λ = M {sub p} , there is still a significant shift on the n {sub s} - r diagram if the massive fields have m ∼ H . On the other hand, if the heavy degree of freedom appears only at the same energy scale as the suppression scale of the dimension-5 operator, then significant shift on the n {sub s} - r diagram takes place at m =Λ ∼ 70 H , which is around the inflationary time-translation symmetry breaking scale. Hence, the systematics from massive fields pose a greater challenge for future high precision experiments for inflationary model selection. This result can be thought of as the impact of UV sensitivity to inflationary observables.

  15. Massive MIMO meets small cell backhaul and cooperation

    CERN Document Server

    Yang, Howard H

    2017-01-01

    This brief explores the utilization of large antenna arrays in massive multiple-input-multiple-output (MIMO) for both interference suppression, where it can improve cell-edge user rates, and for wireless backhaul in small cell networks, where macro base stations can forward data to small access points in an energy efficient way. Massive MIMO is deemed as a critical technology for next generation wireless technology. By deploying an antenna array that has active elements in excess of the number of users, massive MIMO not only provides tremendous diversity gain but also powers new aspects for network design to improve performance. This brief investigates a better utilization of the excessive spatial dimensions to improve network performance. It combines random matrix theory and stochastic geometry to develop an analytical framework that accounts for all the key features of a network, including number of antenna array, base station density, inter-cell interference, random base station deployment, and network tra...

  16. Scattering of massive open strings in pure spinor

    International Nuclear Information System (INIS)

    Park, I.Y.

    2011-01-01

    In Park (2008) , it was proposed that the D-brane geometry could be produced by open string quantum effects. In an effort to verify the proposal, we consider scattering amplitudes involving massive open superstrings. The main goal of this paper is to set the ground for two-loop 'renormalization' of an oriented open superstring on a D-brane and to strengthen our skill in the pure spinor formulation of a superstring, an effective tool for multi-loop string diagrams. We start by reviewing scattering amplitudes of massless states in the 2D component method of the NSR formulation. A few examples of massive string scattering are worked out. The NSR results are then reproduced in the pure spinor formulation. We compute the amplitudes using the unintegrated form of the massive vertex operator constructed by Berkovits and Chandia (2002) . We point out that it may be possible to discover new Riemann type identities involving Jacobi θ-functions by comparing a NSR computation and the corresponding pure spinor computation.

  17. Four new massive pulsating white dwarfs including an ultramassive DAV

    Science.gov (United States)

    Curd, Brandon; Gianninas, A.; Bell, Keaton J.; Kilic, Mukremin; Romero, A. D.; Allende Prieto, Carlos; Winget, D. E.; Winget, K. I.

    2017-06-01

    We report the discovery of four massive (M > 0.8 M⊙) ZZ Ceti white dwarfs, including an ultramassive 1.16 M⊙ star. We obtained ground-based, time series photometry for 13 white dwarfs from the Sloan Digital Sky Survey Data Release 7 and Data Release 10 whose atmospheric parameters place them within the ZZ Ceti instability strip. We detect monoperiodic pulsations in three of our targets (J1015, J1554 and J2038) and identify three periods of pulsation in J0840 (173, 327 and 797 s). Fourier analysis of the remaining nine objects does not indicate variability above the 4 detection threshold. Our preliminary asteroseismic analysis of J0840 yields a stellar mass M = 1.14 ± 0.01 M⊙, hydrogen and helium envelope masses of MH = 5.8 × 10-7 M⊙ and MHe = 4.5 × 10-4 M⊙ and an expected core crystallized mass ratio of 50-70 per cent. J1015, J1554 and J2038 have masses in the range 0.84-0.91 M⊙ and are expected to have a CO core; however, the core of J0840 could consist of highly crystallized CO or ONeMg given its high mass. These newly discovered massive pulsators represent a significant increase in the number of known ZZ Ceti white dwarfs with mass M > 0.85 M⊙, and detailed asteroseismic modelling of J0840 will allow for significant tests of crystallization theory in CO and ONeMg core white dwarfs.

  18. Three-dimensional massive gravity and the bigravity black hole

    International Nuclear Information System (INIS)

    Banados, Maximo; Theisen, Stefan

    2009-01-01

    We study three-dimensional massive gravity formulated as a theory with two dynamical metrics, like the f-g theories of Isham-Salam and Strathdee. The action is parity preserving and has no higher derivative terms. The spectrum contains a single massive graviton. This theory has several features discussed recently in TMG and NMG. We find warped black holes, a critical point, and generalized Brown-Henneaux boundary conditions.

  19. Classical dynamics of brane-world extended objects

    International Nuclear Information System (INIS)

    Vasilic, Milovan

    2010-01-01

    We make use of the universally valid stress-energy conservation law to study the motion of various branelike extended objects in a generic brane-world. Without specifying any particular action, we are able to derive the world-sheet equations that govern the dynamics of brane-world test branes. In particular, the brane-world test particles are shown to follow geodesics with respect to the brane-world induced metric. At the same time, the presence of extended objects is shown to influence the brane-world geometry. It is demonstrated that codimension-1 branes necessarily violate the brane-world smooth structure, while lower-dimensional branes violate the very continuity. In particular, the truly zero-size massive particles are shown not to exist in a continuous brane-world. As an example, static, axially symmetric membrane-world in 4d Minkowski background is analyzed.

  20. Massive graviton and determination of cosmological constant from gauge theory of gravity

    International Nuclear Information System (INIS)

    Mitrut, Alexandru

    2002-01-01

    The universe contains a lot more than the eye meets . Sophisticated experiments search diligently for this invisible dark matter. Here we will describe some theoretical implications of the gravitational gauge theory recently proposed by Ning Wu (hep-th/0112062), namely the possibility of the existence of massive gravitons which fill the intergalactic space. Dark matter is an important problem in cosmology. In gravitational gauge field theory, the following effects should be taken into account to solve this problem: 1) The existence of massive graviton will have some contribution to the dark matter; 2) If the gravitational magnetic field is strong inside a celestial system, the gravitational Lorentz force will provide additional centripetal force for circular motion of a celestial object; 3) The existence of a factor which violate inverse square law of classical gravity. Combining general relativity and gravitational gauge theory the cosmological constant is determined theoretically. The cosmological constant is related to the average vacuum energy of the gravitational gauge field. Because the vacuum energy of the gravitational gauge field is negative, the cosmological constant is positive what generates repulsive force on stars to make the expansion rate of the Universe accelerated. A rough estimation of it gives out its magnitude order 10 -52 m -2 , which is well consistent with experimental results. (authors)

  1. Frontiers of massively parallel scientific computation

    International Nuclear Information System (INIS)

    Fischer, J.R.

    1987-07-01

    Practical applications using massively parallel computer hardware first appeared during the 1980s. Their development was motivated by the need for computing power orders of magnitude beyond that available today for tasks such as numerical simulation of complex physical and biological processes, generation of interactive visual displays, satellite image analysis, and knowledge based systems. Representative of the first generation of this new class of computers is the Massively Parallel Processor (MPP). A team of scientists was provided the opportunity to test and implement their algorithms on the MPP. The first results are presented. The research spans a broad variety of applications including Earth sciences, physics, signal and image processing, computer science, and graphics. The performance of the MPP was very good. Results obtained using the Connection Machine and the Distributed Array Processor (DAP) are presented

  2. Adapting algorithms to massively parallel hardware

    CERN Document Server

    Sioulas, Panagiotis

    2016-01-01

    In the recent years, the trend in computing has shifted from delivering processors with faster clock speeds to increasing the number of cores per processor. This marks a paradigm shift towards parallel programming in which applications are programmed to exploit the power provided by multi-cores. Usually there is gain in terms of the time-to-solution and the memory footprint. Specifically, this trend has sparked an interest towards massively parallel systems that can provide a large number of processors, and possibly computing nodes, as in the GPUs and MPPAs (Massively Parallel Processor Arrays). In this project, the focus was on two distinct computing problems: k-d tree searches and track seeding cellular automata. The goal was to adapt the algorithms to parallel systems and evaluate their performance in different cases.

  3. M2M massive wireless access

    DEFF Research Database (Denmark)

    Zanella, Andrea; Zorzi, Michele; Santos, André F.

    2013-01-01

    In order to make the Internet of Things a reality, ubiquitous coverage and low-complexity connectivity are required. Cellular networks are hence the most straightforward and realistic solution to enable a massive deployment of always connected Machines around the globe. Nevertheless, a paradigm...... shift in the conception and design of future cellular networks is called for. Massive access attempts, low-complexity and cheap machines, sporadic transmission and correlated signals are among the main properties of this new reality, whose main consequence is the disruption of the development...... Access Reservation, Coded Random Access and the exploitation of multiuser detection in random access. Additionally, we will show how the properties of machine originated signals, such as sparsity and spatial/time correlation can be exploited. The end goal of this paper is to provide motivation...

  4. Nonperturbative construction of massive Yang-Mills fields without the Higgs field

    Science.gov (United States)

    Kondo, Kei-Ichi

    2013-01-01

    In order to understand the so-called decoupling solution for gluon and ghost propagators in QCD, we give a nonperturbative construction of a massive vector field describing a non-Abelian massive spin-one particle, which has the correct physical degrees of freedom and is invariant under a modified Becchi-Rouet-Stora-Tyutin transformation, in a massive Yang-Mills model without the Higgs field, i.e., the Curci-Ferrari model. The resulting non-Abelian massive vector boson field is written by using a nonlinear but local transformation from the original fields in the Curci-Ferrari model. As an application, we write down a local mass term for the Yang-Mills field and a dimension-two condensate, which are exactly invariant under the modified Becchi-Rouet-Stora-Tyutin transformation, Lorentz transformation, and color rotation.

  5. Efficient linear precoding for massive MIMO systems using truncated polynomial expansion

    KAUST Repository

    Mü ller, Axel; Kammoun, Abla; Bjö rnson, Emil; Debbah, Mé roú ane

    2014-01-01

    Massive multiple-input multiple-output (MIMO) techniques have been proposed as a solution to satisfy many requirements of next generation cellular systems. One downside of massive MIMO is the increased complexity of computing the precoding

  6. The 2nd Symposium on the Frontiers of Massively Parallel Computations

    Science.gov (United States)

    Mills, Ronnie (Editor)

    1988-01-01

    Programming languages, computer graphics, neural networks, massively parallel computers, SIMD architecture, algorithms, digital terrain models, sort computation, simulation of charged particle transport on the massively parallel processor and image processing are among the topics discussed.

  7. Massive stars in colliding wind systems: the GLAST perspective

    International Nuclear Information System (INIS)

    Reimer, Anita; Reimer, Olaf

    2007-01-01

    Colliding winds of massive stars in binary systems arc considered as candidate sites of high-energy non-thermal photon emission. They are already among the suggested counterparts for a few individual unidentified EGRET sources, but may constitute a detectable source population for the GLAST observatory.The present work investigates such population study of massive colliding wind systems at high-energy gamma-rays. Based on the recent detailed model (Reimer et al. 2006) for non-thermal photon production in prime candidate systems, we unveil the expected characteristics of this source class in the observables accessible at LAT energies. Combining the broadband emission model with the presently cataloged distribution of such systems and their individual parameters allows us to conclude on the expected maximum number of LAT-detections among massive stars in colliding wind binary systems

  8. Geometric approach to a massive p form duality

    International Nuclear Information System (INIS)

    Arias, Pio J.; Leal, Lorenzo; Perez-Mosquera, J. C.

    2003-01-01

    Massive theories of Abelian p forms are quantized in a generalized path representation that leads to a description of the phase space in terms of a pair of dual nonlocal operators analogous to the Wilson loop and the 't Hooft disorder operators. Special attention is devoted to the study of the duality between the topologically massive and self-dual models in 2+1 dimensions. It is shown that these models share a geometric representation in which just one nonlocal operator suffices to describe the observables

  9. Supernovae from massive AGB stars

    NARCIS (Netherlands)

    Poelarends, A.J.T.; Izzard, R.G.; Herwig, F.; Langer, N.; Heger, A.

    2006-01-01

    We present new computations of the final fate of massive AGB-stars. These stars form ONeMg cores after a phase of carbon burning and are called Super AGB stars (SAGB). Detailed stellar evolutionary models until the thermally pulsing AGB were computed using three di erent stellar evolution codes. The

  10. Topologically Massive Higher Spin Gravity

    NARCIS (Netherlands)

    Bagchi, A.; Lal, S.; Saha, A.; Sahoo, B.

    2011-01-01

    We look at the generalisation of topologically massive gravity (TMG) to higher spins, specifically spin-3. We find a special "chiral" point for the spin-three, analogous to the spin-two example, which actually coincides with the usual spin-two chiral point. But in contrast to usual TMG, there is the

  11. Massively parallel quantum computer simulator

    NARCIS (Netherlands)

    De Raedt, K.; Michielsen, K.; De Raedt, H.; Trieu, B.; Arnold, G.; Richter, M.; Lippert, Th.; Watanabe, H.; Ito, N.

    2007-01-01

    We describe portable software to simulate universal quantum computers on massive parallel Computers. We illustrate the use of the simulation software by running various quantum algorithms on different computer architectures, such as a IBM BlueGene/L, a IBM Regatta p690+, a Hitachi SR11000/J1, a Cray

  12. Using Massively Multiplayer Online Role-Playing Games for Online Learning

    Science.gov (United States)

    Childress, Marcus D.; Braswell, Ray

    2006-01-01

    This article addresses the use of a massively multiplayer online role-playing game (MMORPG) to foster communication and interaction and to facilitate cooperative learning in an online course. The authors delineate the definition and history of massively multiplayer online games (MMOGs), and describe current uses of MMORPGs in education, including…

  13. An Alternative Technique in the Control of Massive Presacral Rectal ...

    African Journals Online (AJOL)

    Bleeding control was provided by GORE‑TEX® graft. We conclude that fıxatıon of GORE‑TEX® aortic patch should be kept in mind for uncontrolled massive presacral bleeding. KEYWORDS: GORE‑TEX® graft, presacral bleeding, rectal cancer. An Alternative Technique in the Control of Massive Presacral Rectal. Bleeding: ...

  14. ATLAS searches for New Physics with Boosted Objects

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    With the increase of energy and luminosity at the LHC, searches for new physics are focusing on the multi-TeV mass range. Decays of heavy resonances associated with new physics in this mass range often result in highly boosted very massive objects such as W/Z bosons or Top quarks. New reconstruction techniques, based on jet sub-structure algorithms, are needed to efficiently reconstruct such decay signatures. We will review recent ATLAS developments of jet sub-structure reconstruction tools, and their application to searches for physics beyond the Standard Model.

  15. MAGNETAR-LIKE ACTIVITY FROM THE CENTRAL COMPACT OBJECT IN THE SNR RCW103

    Energy Technology Data Exchange (ETDEWEB)

    Rea, N.; Borghese, A.; Esposito, P.; Zelati, F. Coti [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Postbus 94249, NL-1090 GE Amsterdam (Netherlands); Bachetti, M. [INAF-Osservatorio Astronomico di Cagliari, via della Scienza 5, I-09047 Selargius (Italy); Israel, G. L. [INAF-Osservatorio Astronomico di Roma, via Frascati 33, I-00040, Monteporzio Catone (Italy); De Luca, A., E-mail: rea@ice.csic.es [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, Via E. Bassini 15, I-20133 Milano (Italy)

    2016-09-01

    The 6.67 hr periodicity and the variable X-ray flux of the central compact object (CCO) at the center of the supernova remnant RCW 103, named 1E 161348–5055, have been always difficult to interpret within the standard scenarios of an isolated neutron star (NS) or a binary system. On 2016 June 22, the Burst Alert Telescope (BAT) on board Swift detected a magnetar-like short X-ray burst from the direction of 1E 161348–5055, also coincident with a large long-term X-ray outburst. Here, we report on Chandra , Nuclear Spectroscopic Telescope Array , and Swift (BAT and XRT) observations of this peculiar source during its 2016 outburst peak. In particular, we study the properties of this magnetar-like burst, we discover a hard X-ray tail in the CCO spectrum during outburst, and we study its long-term outburst history (from 1999 to 2016 July). We find the emission properties of 1E 161348–5055 consistent with it being a magnetar. However, in this scenario, the 6.67 hr periodicity can only be interpreted as the rotation period of this strongly magnetized NS, which therefore represents the slowest pulsar ever detected, by orders of magnitude. We briefly discuss the viable slow-down scenarios, favoring a picture involving a period of fall-back accretion after the supernova explosion, similarly to what is invoked (although in a different regime) to explain the “anti-magnetar” scenario for other CCOs.

  16. Massive Open Online Courses on Health and Medicine: Review

    Science.gov (United States)

    2014-01-01

    Background Massive open online courses (MOOCs) have become immensely popular in a short span of time. However, there is very little research exploring MOOCs in the discipline of health and medicine. Objective We aim to provide a review of MOOCs related to health and medicine offered by various MOOC platforms in 2013, by analyzing and comparing the various offerings, their target audience, typical length of course, and credentials offered. We also discuss opportunities and challenges presented by MOOCs in health and medicine. Methods Health and medicine–related MOOCs were gathered using several methods to ensure the richness and completeness of data. Identified MOOC platform websites were used to gather the lists of offerings. In parallel, these MOOC platforms were contacted to access official data on their offerings. Two MOOC aggregator sites (Class Central and MOOC List) were also consulted to gather data on MOOC offerings. Eligibility criteria were defined to concentrate on the courses that were offered in 2013 and primarily on the subject of health and medicine. All language translations in this paper were done using Google Translate. Results The search identified 225 courses, of which 98 were eligible for the review. Over half (58%, 57/98) of the MOOCs considered were offered on the Coursera platform, and 94% (92/98) of all the MOOCs were offered in English. Universities offered 90 MOOCs, and the John Hopkins University offered the largest number of MOOCs (12/90). Only three MOOCs were offered by developing countries (China, West Indies, and Saudi Arabia). The duration of MOOCs varied from 3-20 weeks with an average length of 6.7 weeks. On average, MOOCs expected a participant to work on the material for 4.2 hours a week. Verified certificates were offered by 14 MOOCs, while three others offered other professional recognition. Conclusions The review presents evidence to suggest that MOOCs can be used as a way to provide continuous medical education. It also

  17. How the Monte Carlo production of a wide variety of different samples is centrally handled in the LHCb experiment

    CERN Document Server

    Corti, G; Clemencic, M; Closier, J; Couturier, B; Kreps, M; Mathe, Z; O'Hanlon, D; Robbe, P; Romanovsky, V; Stagni, F; Zhelezov, A

    2015-01-01

    In the LHCb experiment a wide variety of Monte Carlo simulated samples needs to be produced for the experiment's physics program. Monte Carlo productions are handled centrally similarly to all massive processing of data in the experiment. In order to cope with the large set of different types of simulation samples, necessary procedures based on common infrastructures have been set up with a numerical event type identification code used throughout. The various elements in the procedure, from writing a configuration for an event type to deploying them on the production environment, from submitting and processing a request to retrieving the sample produced as well as the conventions established to allow their interplay will be described. The choices made have allowed a high level of automation of Monte Carlo productions that are handled centrally in a transparent way with experts concentrating on their specific tasks. As a result the massive Monte Carlo production of the experiment is efficiently processed on a ...

  18. On the inflationary perturbations of massive higher-spin fields

    Energy Technology Data Exchange (ETDEWEB)

    Kehagias, Alex [Physics Division, National Technical University of Athens, 15780 Zografou Campus, Athens (Greece); Riotto, Antonio, E-mail: kehagias@central.ntua.gr, E-mail: Antonio.Riotto@unige.ch [Department of Theoretical Physics and Center for Astroparticle Physics (CAP), 24 quai E. Ansermet, CH-1211 Geneva 4 (Switzerland)

    2017-07-01

    Cosmological perturbations of massive higher-spin fields are generated during inflation, but they decay on scales larger than the Hubble radius as a consequence of the Higuchi bound. By introducing suitable couplings to the inflaton field, we show that one can obtain statistical correlators of massive higher-spin fields which remain constant or decay very slowly outside the Hubble radius. This opens up the possibility of new observational signatures from inflation.

  19. Long-term outcomes of patients receiving a massive transfusion after trauma.

    Science.gov (United States)

    Mitra, Biswadev; Gabbe, Belinda J; Kaukonen, Kirsi-Maija; Olaussen, Alexander; Cooper, David J; Cameron, Peter A

    2014-10-01

    Resuscitation of patients presenting with hemorrhagic shock after major trauma has evolved to incorporate multiple strategies to maintain tissue perfusion and oxygenation while managing coagulation disorders. We aimed to study changes across time in long-term outcomes in patients with major trauma. A retrospective observational study in a single major trauma center in Australia was conducted. We included all patients with major trauma and massive blood transfusion within the first 24 h during a 6-year period (from 2006 to 2011). The main outcome measures were Glasgow Outcome Score-Extended (GOSE) and work capacity at 6 and 12 months. There were 5,915 patients with major trauma of which 365 (6.2%; 95% confidence interval [95% CI], 5.6 - 6.8) received a massive transfusion. The proportion of major trauma patients receiving a massive transfusion decreased across time from 8.2% to 4.4% (P GOSE at 6 months, and 44% unfavorable GOSE at 12 months. Massive transfusion was independently associated with unfavorable outcomes at 6 months after injury (adjusted odds ratio, 1.56; 95% CI, 1.05 - 2.31) but not at 12 months (adjusted odds ratio, 0.85; 95% CI, 0.72 - 1.01). A significant reduction in massive transfusion rates was observed. Unfavorable long-term outcomes among patients receiving a massive transfusion after trauma were frequent with a substantial proportion of survivors experiencing poor functional status 1 year after injury.

  20. No Evidence for a Fixed Object Limit in Working Memory: Spatial Ensemble Representations Inflate Estimates of Working Memory Capacity for Complex Objects

    Science.gov (United States)

    Brady, Timothy F.; Alvarez, George A.

    2015-01-01

    A central question for models of visual working memory is whether the number of objects people can remember depends on object complexity. Some influential "slot" models of working memory capacity suggest that people always represent 3-4 objects and that only the fidelity with which these objects are represented is affected by object…

  1. RAMA: A file system for massively parallel computers

    Science.gov (United States)

    Miller, Ethan L.; Katz, Randy H.

    1993-01-01

    This paper describes a file system design for massively parallel computers which makes very efficient use of a few disks per processor. This overcomes the traditional I/O bottleneck of massively parallel machines by storing the data on disks within the high-speed interconnection network. In addition, the file system, called RAMA, requires little inter-node synchronization, removing another common bottleneck in parallel processor file systems. Support for a large tertiary storage system can easily be integrated in lo the file system; in fact, RAMA runs most efficiently when tertiary storage is used.

  2. 69 Hotspot Advance Speed - Hotspot Size/Core-Hotspot distance ...

    African Journals Online (AJOL)

    kagoyire

    produced through accretion of matter onto a central object possibly a super massive black hole. The activity of the central engine is often accompanied by highly-relativistic collimated jets/beams (e.g. Begelman et al. 1984) of plasma material formed and accelerated in the vicinity of the black hole (Blandford & Konigl 1979), ...

  3. Massive transfusion protocols: current best practice

    Directory of Open Access Journals (Sweden)

    Hsu YM

    2016-03-01

    Full Text Available Yen-Michael S Hsu,1 Thorsten Haas,2 Melissa M Cushing1 1Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY, USA; 2Department of Anesthesia, University Children's Hospital Zurich, Zurich, Switzerland Abstract: Massive transfusion protocols (MTPs are established to provide rapid blood replacement in a setting of severe hemorrhage. Early optimal blood transfusion is essential to sustain organ perfusion and oxygenation. There are many variables to consider when establishing an MTP, and studies have prospectively evaluated different scenarios and patient populations to establish the best practices to attain improved patient outcomes. The establishment and utilization of an optimal MTP is challenging given the ever-changing patient status during resuscitation efforts. Much of the MTP literature comes from the trauma population, due to the fact that massive hemorrhage is the leading cause of preventable trauma-related death. As we come to further understand the positive and negative clinical impacts of transfusion-related factors, massive transfusion practice can be further refined. This article will first discuss specific MTPs targeting different patient populations and current relevant international guidelines. Then, we will examine a wide selection of therapeutic products to support MTPs, including newly available products and the most suitable of the traditional products. Lastly, we will discuss the best design for an MTP, including ratio-based MTPs and MTPs based on the use of point-of-care coagulation diagnostic tools. Keywords: hemorrhage, MTP, antifibrinolytics, coagulopathy, trauma, ratio, logistics, guidelines, hemostatic

  4. Galaxy bispectrum from massive spinning particles

    Science.gov (United States)

    Moradinezhad Dizgah, Azadeh; Lee, Hayden; Muñoz, Julian B.; Dvorkin, Cora

    2018-05-01

    Massive spinning particles, if present during inflation, lead to a distinctive bispectrum of primordial perturbations, the shape and amplitude of which depend on the masses and spins of the extra particles. This signal, in turn, leaves an imprint in the statistical distribution of galaxies; in particular, as a non-vanishing galaxy bispectrum, which can be used to probe the masses and spins of these particles. In this paper, we present for the first time a new theoretical template for the bispectrum generated by massive spinning particles, valid for a general triangle configuration. We then proceed to perform a Fisher-matrix forecast to assess the potential of two next-generation spectroscopic galaxy surveys, EUCLID and DESI, to constrain the primordial non-Gaussianity sourced by these extra particles. We model the galaxy bispectrum using tree-level perturbation theory, accounting for redshift-space distortions and the Alcock-Paczynski effect, and forecast constraints on the primordial non-Gaussianity parameters marginalizing over all relevant biases and cosmological parameters. Our results suggest that these surveys would potentially be sensitive to any primordial non-Gaussianity with an amplitude larger than fNL≈ 1, for massive particles with spins 2, 3, and 4. Interestingly, if non-Gaussianities are present at that level, these surveys will be able to infer the masses of these spinning particles to within tens of percent. If detected, this would provide a very clear window into the particle content of our Universe during inflation.

  5. Bronchial Artery Embolization for Massive Hemoptysis: a Retrospective Study

    Directory of Open Access Journals (Sweden)

    Ali Fani

    2013-05-01

    Full Text Available   Introduction: To assess the efficacy and safety of bronchial artery embolization in the treatment of massive hemoptysis.   Materials and Methods: A retrospective study on 46 patients (26 males and 20 females who were referred to the Razavi Hospital from April 2009 to May 2012 with massive hemoptysis and had bronchial artery embolization procedures. General characteristics of the patients including age, gender, etiology, and thorax computed tomograms, findings of bronchial angiographic, results of the embolization, complications related to bronchial artery embolization and clinical outcome during follow-up were reviewed. Results: The etiology included previous pulmonary tuberculosis in 20 cases, previous tuberculosis with bronchiectasis in 16 cases, bronchiectasis in 6 cases, and active pulmonary tuberculosis in one case. No identifiable causes could be detected in three patients. Moreover, massive hemoptysis was successfully and immediately controlled following the embolization procedure in all patients. One patient developed recurrent hemoptysis during one month following the procedure and was treated by re-embolization. No major procedure–related complication such as bronchial infarction was identified However none of the patientsexperienced neurological complications. Conclusion: Bronchial artery embolization is a safe and effective means of controlling massive hemoptysis and should be regarded as the first-line treatment for this condition.

  6. On the equivalence of massive qed with renormalizable and in unitary gauge

    International Nuclear Information System (INIS)

    Abdalla, E.

    1978-03-01

    In the framework of BPHZ renormalization procedure, we discuss the equivalence between 4-dimensional renormalizable massive quantum electrodynamics (Stueckelberg lagrangian), and massive QED in the unitary gauge

  7. Cosmological viability of theories with massive spin-2 fields

    Energy Technology Data Exchange (ETDEWEB)

    Koennig, Frank

    2017-03-30

    Theories of spin-2 fields take on a particular role in modern physics. They do not only describe the mediation of gravity, the only theory of fundamental interactions of which no quantum field theoretical description exists, it furthermore was thought that they necessarily predict massless gauge bosons. Just recently, a consistent theory of a massive graviton was constructed and, subsequently, generalized to a bimetric theory of two interacting spin-2 fields. This thesis studies both the viability and consequences at cosmological scales in massive gravity as well as bimetric theories. We show that all consistent models that are free of gradient and ghost instabilities behave like the cosmological standard model, LCDM. In addition, we construct a new theory of massive gravity which is stable at both classical background and quantum level, even though it suffers from the Boulware-Deser ghost.

  8. Impact analysis on a massively parallel computer

    International Nuclear Information System (INIS)

    Zacharia, T.; Aramayo, G.A.

    1994-01-01

    Advanced mathematical techniques and computer simulation play a major role in evaluating and enhancing the design of beverage cans, industrial, and transportation containers for improved performance. Numerical models are used to evaluate the impact requirements of containers used by the Department of Energy (DOE) for transporting radioactive materials. Many of these models are highly compute-intensive. An analysis may require several hours of computational time on current supercomputers despite the simplicity of the models being studied. As computer simulations and materials databases grow in complexity, massively parallel computers have become important tools. Massively parallel computational research at the Oak Ridge National Laboratory (ORNL) and its application to the impact analysis of shipping containers is briefly described in this paper

  9. Classification of Variable Objects in Massive Sky Monitoring Surveys

    Science.gov (United States)

    Woźniak, Przemek; Wyrzykowski, Łukasz; Belokurov, Vasily

    2012-03-01

    The era of great sky surveys is upon us. Over the past decade we have seen rapid progress toward a continuous photometric record of the optical sky. Numerous sky surveys are discovering and monitoring variable objects by hundreds of thousands. Advances in detector, computing, and networking technology are driving applications of all shapes and sizes ranging from small all sky monitors, through networks of robotic telescopes of modest size, to big glass facilities equipped with giga-pixel CCD mosaics. The Large Synoptic Survey Telescope will be the first peta-scale astronomical survey [18]. It will expand the volume of the parameter space available to us by three orders of magnitude and explore the mutable heavens down to an unprecedented level of sensitivity. Proliferation of large, multidimensional astronomical data sets is stimulating the work on new methods and tools to handle the identification and classification challenge [3]. Given exponentially growing data rates, automated classification of variability types is quickly becoming a necessity. Taking humans out of the loop not only eliminates the subjective nature of visual classification, but is also an enabling factor for time-critical applications. Full automation is especially important for studies of explosive phenomena such as γ-ray bursts that require rapid follow-up observations before the event is over. While there is a general consensus that machine learning will provide a viable solution, the available algorithmic toolbox remains underutilized in astronomy by comparison with other fields such as genomics or market research. Part of the problem is the nature of astronomical data sets that tend to be dominated by a variety of irregularities. Not all algorithms can handle gracefully uneven time sampling, missing features, or sparsely populated high-dimensional spaces. More sophisticated algorithms and better tools available in standard software packages are required to facilitate the adoption of

  10. The Intermediate-mass Young Stellar Object 08576nr292: Discovery of A Disk-Jet System

    NARCIS (Netherlands)

    Ellerbroek, L.E.; Kaper, L.; Bik, A.; de Koter, A.; Horrobin, M.; Puga, E.; Sana, H.; Waters, L.B.F.M.

    2011-01-01

    We present observations of the embedded massive young stellar object (YSO) candidate 08576nr292, obtained with X-shooter and SINFONI on the ESO Very Large Telescope (VLT). The flux-calibrated, medium-resolution X-shooter spectrum (300–2500 nm) includes over 300 emission lines, but no (photospheric)

  11. Multi-mode sensor processing on a dynamically reconfigurable massively parallel processor array

    Science.gov (United States)

    Chen, Paul; Butts, Mike; Budlong, Brad; Wasson, Paul

    2008-04-01

    This paper introduces a novel computing architecture that can be reconfigured in real time to adapt on demand to multi-mode sensor platforms' dynamic computational and functional requirements. This 1 teraOPS reconfigurable Massively Parallel Processor Array (MPPA) has 336 32-bit processors. The programmable 32-bit communication fabric provides streamlined inter-processor connections with deterministically high performance. Software programmability, scalability, ease of use, and fast reconfiguration time (ranging from microseconds to milliseconds) are the most significant advantages over FPGAs and DSPs. This paper introduces the MPPA architecture, its programming model, and methods of reconfigurability. An MPPA platform for reconfigurable computing is based on a structural object programming model. Objects are software programs running concurrently on hundreds of 32-bit RISC processors and memories. They exchange data and control through a network of self-synchronizing channels. A common application design pattern on this platform, called a work farm, is a parallel set of worker objects, with one input and one output stream. Statically configured work farms with homogeneous and heterogeneous sets of workers have been used in video compression and decompression, network processing, and graphics applications.

  12. THE ELM SURVEY. V. MERGING MASSIVE WHITE DWARF BINARIES

    International Nuclear Information System (INIS)

    Brown, Warren R.; Kenyon, Scott J.; Kilic, Mukremin; Gianninas, A.; Allende Prieto, Carlos

    2013-01-01

    We present the discovery of 17 low-mass white dwarfs (WDs) in short-period (P ≤ 1 day) binaries. Our sample includes four objects with remarkable log g ≅ 5 surface gravities and orbital solutions that require them to be double degenerate binaries. All of the lowest surface gravity WDs have metal lines in their spectra implying long gravitational settling times or ongoing accretion. Notably, six of the WDs in our sample have binary merger times 0.9 M ☉ companions. If the companions are massive WDs, these four binaries will evolve into stable mass transfer AM CVn systems and possibly explode as underluminous supernovae. If the companions are neutron stars, then these may be millisecond pulsar binaries. These discoveries increase the number of detached, double degenerate binaries in the ELM Survey to 54; 31 of these binaries will merge within a Hubble time.

  13. THE ELM SURVEY. V. MERGING MASSIVE WHITE DWARF BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Warren R.; Kenyon, Scott J. [Smithsonian Astrophysical Observatory, 60 Garden St, Cambridge, MA 02138 (United States); Kilic, Mukremin; Gianninas, A. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK, 73019 (United States); Allende Prieto, Carlos, E-mail: wbrown@cfa.harvard.edu, E-mail: skenyon@cfa.harvard.edu, E-mail: kilic@ou.edu, E-mail: alexg@nhn.ou.edu, E-mail: callende@iac.es [Instituto de Astrofisica de Canarias, E-38205, La Laguna, Tenerife (Spain)

    2013-05-20

    We present the discovery of 17 low-mass white dwarfs (WDs) in short-period (P {<=} 1 day) binaries. Our sample includes four objects with remarkable log g {approx_equal} 5 surface gravities and orbital solutions that require them to be double degenerate binaries. All of the lowest surface gravity WDs have metal lines in their spectra implying long gravitational settling times or ongoing accretion. Notably, six of the WDs in our sample have binary merger times <10 Gyr. Four have {approx}>0.9 M{sub Sun} companions. If the companions are massive WDs, these four binaries will evolve into stable mass transfer AM CVn systems and possibly explode as underluminous supernovae. If the companions are neutron stars, then these may be millisecond pulsar binaries. These discoveries increase the number of detached, double degenerate binaries in the ELM Survey to 54; 31 of these binaries will merge within a Hubble time.

  14. THE PREVALENCE AND IMPACT OF WOLF–RAYET STARS IN EMERGING MASSIVE STAR CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Sokal, Kimberly R.; Johnson, Kelsey E.; Indebetouw, Rémy [Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903 (United States); Massey, Philip, E-mail: krs9tb@virginia.edu [Lowell Observatory, 1400 W Mars Hill Road, Flagstaff, AZ 86001 (United States)

    2016-08-01

    We investigate Wolf–Rayet (WR) stars as a source of feedback contributing to the removal of natal material in the early evolution of massive star clusters. Despite previous work suggesting that massive star clusters clear out their natal material before the massive stars evolve into the WR phase, WR stars have been detected in several emerging massive star clusters. These detections suggest that the timescale for clusters to emerge can be at least as long as the time required to produce WR stars (a few million years), and could also indicate that WR stars may be providing the tipping point in the combined feedback processes that drive a massive star cluster to emerge. We explore the potential overlap between the emerging phase and the WR phase with an observational survey to search for WR stars in emerging massive star clusters hosting WR stars. We select candidate emerging massive star clusters from known radio continuum sources with thermal emission and obtain optical spectra with the 4 m Mayall Telescope at Kitt Peak National Observatory and the 6.5 m MMT.{sup 4} We identify 21 sources with significantly detected WR signatures, which we term “emerging WR clusters.” WR features are detected in ∼50% of the radio-selected sample, and thus we find that WR stars are commonly present in currently emerging massive star clusters. The observed extinctions and ages suggest that clusters without WR detections remain embedded for longer periods of time, and may indicate that WR stars can aid, and therefore accelerate, the emergence process.

  15. MAX-SLNR Precoding Algorithm for Massive MIMO System

    Directory of Open Access Journals (Sweden)

    Jiang Jing

    2016-01-01

    Full Text Available Pilot Contamination obviously degrades the system performance of Massive MIMO systems. In this paper, a downlink precoding algorithm based on the Signal-to- Leakage-plus-Noise-Ratio (SLNR criterion is put forward. First, the impact of Pilot Contamination on SLNR is analyzed,then the precoding matrix is calculated with the eigenvalues decomposition of SLNR, which not only maximize the array gains of the target user, but also minimize the impact of Pilot Contamination and the leak to the users of other cells. Further, a simplified solution is derived, in which the impact of Pilot Contamination can be suppressed only with the large-scale fading coefficients. Simulation results reveal that: in the scenario of the serious pilot contamination, the proposed algorithm can avoid the performance loss caused by the pilot contamination compared with the conventional Massive MIMO precoding algorithm. Thus the proposed algorithm can acquire the perfect performance gains of Massive MIMO system and has better practical value since the large-scale fading coefficients are easy to measure and feedback.

  16. Non-thermal Processes in Colliding-wind Massive Binaries: the Contribution of Simbol-X to a Multiwavelength Investigation

    Science.gov (United States)

    De Becker, Michaël; Blomme, Ronny; Micela, Giusi; Pittard, Julian M.; Rauw, Gregor; Romero, Gustavo E.; Sana, Hugues; Stevens, Ian R.

    2009-05-01

    Several colliding-wind massive binaries are known to be non-thermal emitters in the radio domain. This constitutes strong evidence for the fact that an efficient particle acceleration process is at work in these objects. The acceleration mechanism is most probably the Diffusive Shock Acceleration (DSA) process in the presence of strong hydrodynamic shocks due to the colliding-winds. In order to investigate the physics of this particle acceleration, we initiated a multiwavelength campaign covering a large part of the electromagnetic spectrum. In this context, the detailed study of the hard X-ray emission from these sources in the SIMBOL-X bandpass constitutes a crucial element in order to probe this still poorly known topic of astrophysics. It should be noted that colliding-wind massive binaries should be considered as very valuable targets for the investigation of particle acceleration in a similar way as supernova remnants, but in a different region of the parameter space.

  17. Central bank independence and financial instability

    NARCIS (Netherlands)

    Klomp, J.G.; de Haan, J.

    2009-01-01

    It has been argued that central bank independence (CBI) may not only be beneficial for reaching the objective of price stability, but also for maintaining financial stability. Greater independence from external pressure implies that central banks are less politically constrained in acting to prevent

  18. Central Nervous System Symptoms Due to Transient Methemoglobinemia in a Child With G6PD Deficiency.

    Science.gov (United States)

    Sharma, Shreya; Srinivasaraghavan, Rangan; Krishnamurthy, Sriram

    2017-01-01

    The authors herein report a 5-year-old child who presented with massive hemolysis, irritability, and cyanosis. The final diagnosis was glucose-6-phosphate dehydrogenase deficiency with associated central nervous system symptoms probably because of concomitantly acquired methemoglobinemia following oxidant drug exposure. The associated acute-onset anemia would have contributed to the development of cerebral anoxia-related seizures and encephalopathy.

  19. A Massive, Cooling-Flow-Induced Starburst in the Core of a Highly Luminous Galaxy Cluster

    Science.gov (United States)

    McDonald, M.; Bayliss, M.; Benson, B. A.; Foley, R. J.; Ruel, J.; Sullivan, P.; Veilleux, S.; Aird, K. A.; Ashby, M. L. N.; Bautz, M.; hide

    2012-01-01

    In the cores of some galaxy clusters the hot intracluster plasma is dense enough that it should cool radiatively in the cluster s lifetime, leading to continuous "cooling flows" of gas sinking towards the cluster center, yet no such cooling flow has been observed. The low observed star formation rates and cool gas masses for these "cool core" clusters suggest that much of the cooling must be offset by astrophysical feedback to prevent the formation of a runaway cooling flow. Here we report X-ray, optical, and infrared observations of the galaxy cluster SPT-CLJ2344-4243 at z = 0.596. These observations reveal an exceptionally luminous (L(sub 2-10 keV) = 8.2 10(exp 45) erg/s) galaxy cluster which hosts an extremely strong cooling flow (M(sub cool) = 3820 +/- 530 Stellar Mass/yr). Further, the central galaxy in this cluster appears to be experiencing a massive starburst (740 +/- 160 Stellar Mass/ yr), which suggests that the feedback source responsible for preventing runaway cooling in nearby cool core clusters may not yet be fully established in SPT-CLJ2344-4243. This large star formation rate implies that a significant fraction of the stars in the central galaxy of this cluster may form via accretion of the intracluster medium, rather than the current picture of central galaxies assembling entirely via mergers.

  20. The relationships into the video games massively multiplayer online role-playing game (MMORPG

    Directory of Open Access Journals (Sweden)

    Alvaro Alfonso Acevedo

    2016-11-01

    Full Text Available This paper is about the relationships dynamics in the virtuality of the gamers into the massively multiplayer online role-playing game “Perfect World” in the not ocifial latinamerican server “Comunidad Zero”. The main objective of this study is to describe the dynamics of the relationships, analyzing them from the context of the game using the virtual ethnography, understanding the emotional interactions between couples, through a case study. During the development of research, were found several categories related to affective interactions of pre-attachment, manifested in virtual environments of the game and that ultimately manage to simulate the engagement dynamics of the physical contexts.

  1. A RAPIDLY EVOLVING REGION IN THE GALACTIC CENTER: WHY S-STARS THERMALIZE AND MORE MASSIVE STARS ARE MISSING

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xian; Amaro-Seoane, Pau, E-mail: Xian.Chen@aei.mpg.de, E-mail: Pau.Amaro-Seoane@aei.mpg.de [Max Planck Institut für Gravitationsphysik (Albert-Einstein-Institut), D-14476 Potsdam (Germany)

    2014-05-10

    The existence of ''S-stars'' within a distance of 1'' from Sgr A* contradicts our understanding of star formation, due to Sgr A* 's forbiddingly violent environment. A suggested possibility is that they form far away and were brought in by some fast dynamical process, since they are young. Nonetheless, all conjectured mechanisms either fail to reproduce their eccentricities—without violating their young age—or cannot explain the problem of {sup i}nverse mass segregation{sup :} the fact that lighter stars (the S-stars) are closer to Sgr A* and more massive ones, Wolf-Rayet (WR) and O-stars, are farther out. In this Letter we propose that the mechanism responsible for both the distribution of the eccentricities and the paucity of massive stars is the Kozai-Lidov-like resonance induced by a sub-parsec disk recently discovered in the Galactic center. Considering that the disk probably extended to a smaller radius in the past, we show that in as short as (a few) 10{sup 6} yr, the stars populating the innermost 1'' region would redistribute in angular-momentum space and recover the observed ''super-thermal'' distribution. Meanwhile, WR and O-stars in the same region intermittently attain ample eccentricities that will lead to their tidal disruptions by the central massive black hole. Our results provide new evidences that Sgr A* was powered several millions years ago by an accretion disk as well as by tidal stellar disruptions.

  2. Acute tryptophan depletion dose dependently impairs object memory in serotonin transporter knockout rats

    NARCIS (Netherlands)

    Olivier, J D A; Jans, L A W; Korte-Bouws, G A H; Korte, S M; Deen, P M T; Cools, A R; Ellenbroek, B A; Blokland, A

    2008-01-01

    RATIONALE: Acute tryptophan depletion (ATD) transiently lowers central serotonin levels and can induce depressive mood states and cognitive defects. Previous studies have shown that ATD impairs object recognition in rats. OBJECTIVES: As individual differences exist in central serotonin

  3. ADDITIONAL MASSIVE BINARIES IN THE CYGNUS OB2 ASSOCIATION

    International Nuclear Information System (INIS)

    Kiminki, Daniel C.; Kobulnicky, Henry A.; Ewing, Ian; Lundquist, Michael; Alexander, Michael; Vargas-Alvarez, Carlos; Choi, Heather; Bagley Kiminki, Megan M.; Henderson, C. B.

    2012-01-01

    We report the discovery and orbital solutions for two new OB binaries in the Cygnus OB2 Association, MT311 (B2V + B3V) and MT605 (B0.5V + B2.5:V). We also identify the system MT429 as a probable triple system consisting of a tight eclipsing 2.97 day B3V+B6V pair and a B0V at a projected separation of 138 AU. We further provide the first spectroscopic orbital solutions to the eclipsing, double-lined, O-star binary MT696 (O9.5V + B1:V), the double-lined, early B binary MT720 (B0-1V + B1-2V), and the double-lined, O-star binary MT771 (O7V + O9V). These systems exhibit orbital periods between 1.5 days and 12.3 days, with the majority having P <6 days. The two new binary discoveries and six spectroscopic solutions bring the total number of known massive binaries in the central region of the Cygnus OB2 Association to 20, with all but two having full orbital solutions.

  4. ADDITIONAL MASSIVE BINARIES IN THE CYGNUS OB2 ASSOCIATION

    Energy Technology Data Exchange (ETDEWEB)

    Kiminki, Daniel C.; Kobulnicky, Henry A.; Ewing, Ian; Lundquist, Michael; Alexander, Michael; Vargas-Alvarez, Carlos; Choi, Heather [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82070 (United States); Bagley Kiminki, Megan M. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Henderson, C. B. [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States)

    2012-03-01

    We report the discovery and orbital solutions for two new OB binaries in the Cygnus OB2 Association, MT311 (B2V + B3V) and MT605 (B0.5V + B2.5:V). We also identify the system MT429 as a probable triple system consisting of a tight eclipsing 2.97 day B3V+B6V pair and a B0V at a projected separation of 138 AU. We further provide the first spectroscopic orbital solutions to the eclipsing, double-lined, O-star binary MT696 (O9.5V + B1:V), the double-lined, early B binary MT720 (B0-1V + B1-2V), and the double-lined, O-star binary MT771 (O7V + O9V). These systems exhibit orbital periods between 1.5 days and 12.3 days, with the majority having P <6 days. The two new binary discoveries and six spectroscopic solutions bring the total number of known massive binaries in the central region of the Cygnus OB2 Association to 20, with all but two having full orbital solutions.

  5. Objects of Worship in South Asian Religions

    DEFF Research Database (Denmark)

    Objects of worship are an aspect of the material dimension of lived religion in South Asia. The omnipresence of these objects and their use is a theme which cuts across the religious traditions in the pluralistic religious culture of the region. Divine power becomes manifest in the objects and fo...... objects of worship, the book contributes to an understanding of the central significance of these objects in the religious and social life of South Asia. It will be of interest to students and scholars of Religious Studies and South Asian Religion, Culture and Society....

  6. The coupling between pulsation and mass loss in massive stars

    OpenAIRE

    Townsend, Rich

    2007-01-01

    To what extent can pulsational instabilities resolve the mass-loss problem of massive stars? How important is pulsation in structuring and modulating the winds of these stars? What role does pulsation play in redistributing angular momentum in massive stars? Although I cannot offer answers to these questions, I hope at the very least to explain how they come to be asked.

  7. Accountability of central banks: aspects and quantification

    Directory of Open Access Journals (Sweden)

    J. DE HAAN

    1999-06-01

    Full Text Available The work examines the relationship between central bank independence and accountability. The authors do this by using an indicator for central bank accountability based on the laws of 16 central banks. Central bank accountability is identified as having three distinct features, namely, the explicit definition and ranking of the objectives of monetary policy, the transparency of the actual monetary policy, and the final responsibility to monetary policy.

  8. Evolution of massive stars

    International Nuclear Information System (INIS)

    Loore, C. de

    1984-01-01

    The evolution of stars with masses larger than 15 sun masses is reviewed. These stars have large convective cores and lose a substantial fraction of their matter by stellar wind. The treatment of convection and the parameterisation of the stellar wind mass loss are analysed within the context of existing disagreements between theory and observation. The evolution of massive close binaries and the origin of Wolf-Rayet Stars and X-ray binaries is also sketched. (author)

  9. PARALLEL SPATIOTEMPORAL SPECTRAL CLUSTERING WITH MASSIVE TRAJECTORY DATA

    Directory of Open Access Journals (Sweden)

    Y. Z. Gu

    2017-09-01

    Full Text Available Massive trajectory data contains wealth useful information and knowledge. Spectral clustering, which has been shown to be effective in finding clusters, becomes an important clustering approaches in the trajectory data mining. However, the traditional spectral clustering lacks the temporal expansion on the algorithm and limited in its applicability to large-scale problems due to its high computational complexity. This paper presents a parallel spatiotemporal spectral clustering based on multiple acceleration solutions to make the algorithm more effective and efficient, the performance is proved due to the experiment carried out on the massive taxi trajectory dataset in Wuhan city, China.

  10. A discrete ordinate response matrix method for massively parallel computers

    International Nuclear Information System (INIS)

    Hanebutte, U.R.; Lewis, E.E.

    1991-01-01

    A discrete ordinate response matrix method is formulated for the solution of neutron transport problems on massively parallel computers. The response matrix formulation eliminates iteration on the scattering source. The nodal matrices which result from the diamond-differenced equations are utilized in a factored form which minimizes memory requirements and significantly reduces the required number of algorithm utilizes massive parallelism by assigning each spatial node to a processor. The algorithm is accelerated effectively by a synthetic method in which the low-order diffusion equations are also solved by massively parallel red/black iterations. The method has been implemented on a 16k Connection Machine-2, and S 8 and S 16 solutions have been obtained for fixed-source benchmark problems in X--Y geometry

  11. CENTRAL ENGINE MEMORY OF GAMMA-RAY BURSTS AND SOFT GAMMA-RAY REPEATERS

    International Nuclear Information System (INIS)

    Zhang, Bin-Bin; Castro-Tirado, Alberto J.; Zhang, Bing

    2016-01-01

    Gamma-ray bursts (GRBs) are bursts of γ-rays generated from relativistic jets launched from catastrophic events such as massive star core collapse or binary compact star coalescence. Previous studies suggested that GRB emission is erratic, with no noticeable memory in the central engine. Here we report a discovery that similar light curve patterns exist within individual bursts for at least some GRBs. Applying the Dynamic Time Warping method, we show that similarity of light curve patterns between pulses of a single burst or between the light curves of a GRB and its X-ray flare can be identified. This suggests that the central engine of at least some GRBs carries “memory” of its activities. We also show that the same technique can identify memory-like emission episodes in the flaring emission in soft gamma-ray repeaters (SGRs), which are believed to be Galactic, highly magnetized neutron stars named magnetars. Such a phenomenon challenges the standard black hole central engine models for GRBs, and suggest a common physical mechanism behind GRBs and SGRs, which points toward a magnetar central engine of GRBs

  12. Massive Open Online Courses (MOOCs, embedded systems, blended courses, sentiment analysis.

    Directory of Open Access Journals (Sweden)

    Ciprian Bogdan Chirila

    2017-04-01

    Full Text Available Nowadays, regional IT industry lacks human resources because of the pressure created on the labor market by the high-value economic projects. Tutors tend to be more and more loaded with teaching, research, and administrative tasks. Students tend to use more and more electronically devices like laptops, tablets, and mobile phones in their learning sessions. In this context, universities should rely more on technologies like: LMSs (Learning Management Systems, MOOCs (Massive Open Online Courses, and why not GLOs (Generative Learning Objects or evenAGLOs (Auto-generative Learning Objects. Auto-generative learning objects are reusable pedagogical patterns to be instantiated with generated content based on random numbers to fulfill the learning objectives. Many online e-learning resources are available containing interactive presentations, gamifications of several learning objectives. Such e-learning resources are hard to reuse and even harder to modify and adapt to; each discipline needs this because it needs access to the source code, programming knowledge to change, test and deploy etc. In this paper, we will focus on computer science disciplines needed in the regional IT industry, namely data structures and algorithms. We will show how a tutor can build several auto-generative learning objects in order to assess the knowledge of a class of students. We will start with the design of the generic models, then we will assess the generated content created with the help of a tool based on meta-programming, afterwards, we will deploy the content to a webserver to be consumed by the students. Finally, we will evaluate the assessed results and discuss the approach both from the student’s and the tutor’s perspective.

  13. Has Research on Collaborative Learning Technologies Addressed Massiveness? A Literature Review

    Science.gov (United States)

    Manathunga, Kalpani; Hernández-Leo, Davinia

    2015-01-01

    There is a growing interest in understanding to what extent innovative educational technologies can be used to support massive courses. Collaboration is one of the main desired elements in massive learning actions involving large communities of participants. Accumulated research in collaborative learning technologies has proposed and evaluated…

  14. Massive vulvar edema in a woman with preeclampsia: a case report.

    Science.gov (United States)

    Daponte, Alexandros; Skentou, Hara; Dimopoulos, Konstantinos D; Kallitsaris, Athanasios; Messinis, Ioannis E

    2007-11-01

    Massive vulvar edema in a woman with preeclampsia preceded the development of massive ascites and impending eclampsia. A 17-year-old preeclamptic, primiparous woman was admitted with preeclampsia and massive vulvar edema. Other causes were excluded. The vulvar edema increased as the blood pressure and ascites increased, and a severe headache developed. Cesarean section for increasing preclampsia was performed. In the puerperium, the blood pressure improved and vulvar edema resolved. The clinical picture of the vulvar edema correlated with the severity of the preeclampsia. The presence of vulvar edema in women with preeclampsia should indicate immediate admission to the hospital. These patients must be considered as at high risk, and close monitoring must be instituted. In our case, vulvar edema preceded massive ascites development. We assume a common development mechanism for these signs in preeclampsia, due mainly to increased capillary permeability and hypoalbuminemia. The attending physician must be prepared for immediate delivery and possible preeclampsia complications in these patients.

  15. EVIDENCE FOR REDUCED SPECIFIC STAR FORMATION RATES IN THE CENTERS OF MASSIVE GALAXIES AT z  = 4

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Intae; Finkelstein, Steven L. [Department of Astronomy, The University of Texas at Austin, Austin, TX 78712 (United States); Song, Mimi; Straughn, Amber N. [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Dickinson, Mark [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Dekel, Avishai [Center for Astrophysics and Planetary Science, Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Ferguson, Henry C.; Koekemoer, Anton M.; Ryan, Russell E. Jr.; Salmon, Brett [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Fontana, Adriano [INAF—Osservatorio Astronomico di Roma, via di Frascati 33, I-00040, Monte Porzio Catone (Italy); Lu, Yu [The Observatories, The Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Mobasher, Bahram [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Papovich, Casey, E-mail: itjung@astro.as.utexas.edu [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States)

    2017-01-01

    We perform the first spatially resolved stellar population study of galaxies in the early universe ( z = 3.5–6.5), utilizing the Hubble Space Telescope Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey imaging data set over the GOODS-S field. We select a sample of 418 bright and extended galaxies at z  = 3.5–6.5 from a parent sample of ∼8000 photometric-redshift-selected galaxies from Finkelstein et al. We first examine galaxies at 3.5 ≲ z ≲ 4.0 using additional deep K -band survey data from the HAWK-I UDS and GOODS Survey which covers the 4000 Å break at these redshifts. We measure the stellar mass, star formation rate, and dust extinction for galaxy inner and outer regions via spatially resolved spectral energy distribution fitting based on a Markov Chain Monte Carlo algorithm. By comparing specific star formation rates (sSFRs) between inner and outer parts of the galaxies we find that the majority of galaxies with high central mass densities show evidence for a preferentially lower sSFR in their centers than in their outer regions, indicative of reduced sSFRs in their central regions. We also study galaxies at z ∼ 5 and 6 (here limited to high spatial resolution in the rest-frame ultraviolet only), finding that they show sSFRs which are generally independent of radial distance from the center of the galaxies. This indicates that stars are formed uniformly at all radii in massive galaxies at z  ∼ 5–6, contrary to massive galaxies at z ≲ 4.

  16. Mechanical Thrombectomy for Early Treatment of Massive Pulmonary Embolism

    International Nuclear Information System (INIS)

    Reekers, Jim A.; Baarslag, Henk Jan; Koolen, Maria G.J.; Delden, Otto van; Beek, Edwin J.R. van

    2003-01-01

    We report our technique and results of percutaneous mechanical thrombectomy in a consecutive series of eight patients with massive PE. We also discuss the possible role of mechanical PE thrombectomy. Eight consecutive patients with acute massive PE, with or without hemodynamic impairment, were treated with mechanical thrombectomy. We used a modified 7-fr hydrolyzer catheter. The treatment was combined with systemic fibrinolysis. From the logistic and technical point we encountered no problems. All patients showed significant improvement while still in the angiography suite. There were no bleeding complications and no other events related to the procedure. Despite the clinical improvement, one patient died shortly after the procedure from cardiac failure. In all patients there was an acute increase in PO2 to normal values. Only a mean of about 50% of all local thrombus could be removed (range 30-80%). The mean PAP pre-intervention decreased only minimally from 42.5 mmHg to 36.3 mm Hg post-intervention (not significant). In three patients, the PAP continues to remain high at follow-up. The most important feature of mechanical thrombectomy for massive PE is the immediate improvement of the cardiac output, PO2, and clinical situation, overcoming the first critical hours after massive PE. The amount of thrombus reduction seems not to be an important parameter

  17. Massive ovarian edema, due to adjacent appendicitis.

    Science.gov (United States)

    Callen, Andrew L; Illangasekare, Tushani; Poder, Liina

    2017-04-01

    Massive ovarian edema is a benign clinical entity, the imaging findings of which can mimic an adnexal mass or ovarian torsion. In the setting of acute abdominal pain, identifying massive ovarian edema is a key in avoiding potential fertility-threatening surgery in young women. In addition, it is important to consider other contributing pathology when ovarian edema is secondary to another process. We present a case of a young woman presenting with subacute abdominal pain, whose initial workup revealed marked enlarged right ovary. Further imaging, diagnostic tests, and eventually diagnostic laparoscopy revealed that the ovarian enlargement was secondary to subacute appendicitis, rather than a primary adnexal process. We review the classic ultrasound and MRI imaging findings and pitfalls that relate to this diagnosis.

  18. Close entrainment of massive molecular gas flows by radio bubbles in the central galaxy of Abell 1795

    Science.gov (United States)

    Russell, H. R.; McNamara, B. R.; Fabian, A. C.; Nulsen, P. E. J.; Combes, F.; Edge, A. C.; Hogan, M. T.; McDonald, M.; Salomé, P.; Tremblay, G.; Vantyghem, A. N.

    2017-12-01

    We present new ALMA observations tracing the morphology and velocity structure of the molecular gas in the central galaxy of the cluster Abell 1795. The molecular gas lies in two filaments that extend 5-7 kpc to the N and S from the nucleus and project exclusively around the outer edges of two inner radio bubbles. Radio jets launched by the central active galactic nucleus have inflated bubbles filled with relativistic plasma into the hot atmosphere surrounding the central galaxy. The N filament has a smoothly increasing velocity gradient along its length from the central galaxy's systemic velocity at the nucleus to -370 km s^{-1}, the average velocity of the surrounding galaxies, at the furthest extent. The S filament has a similarly smooth but shallower velocity gradient and appears to have partially collapsed in a burst of star formation. The close spatial association with the radio lobes, together with the ordered velocity gradients and narrow velocity dispersions, shows that the molecular filaments are gas flows entrained by the expanding radio bubbles. Assuming a Galactic XCO factor, the total molecular gas mass is 3.2 ± 0.2 × 109 M⊙. More than half lies above the N radio bubble. Lifting the molecular clouds appears to require an infeasibly efficient coupling between the molecular gas and the radio bubble. The energy required also exceeds the mechanical power of the N radio bubble by a factor of 2. Stimulated feedback, where the radio bubbles lift low-entropy X-ray gas that becomes thermally unstable and rapidly cools in situ, provides a plausible model. Multiple generations of radio bubbles are required to lift this substantial gas mass. The close morphological association then indicates that the cold gas either moulds the newly expanding bubbles or is itself pushed aside and shaped as they inflate.

  19. Massive and massless supersymmetry: Multiplet structure and unitary irreducible representations

    International Nuclear Information System (INIS)

    Jarvis, P.D.

    1976-01-01

    UIR's of the supersymmetry algebra for the massive and massless cases are analyzed covariantly (without the use of induced representations) in terms of their component spins. For the massive case normalized basis vectors vertical-barp 2 >0, j 0 ; sigma; pjlambda> are constructed, where j 0 is the ''superspin'' and sigma is an additional quantum number serving to distinguish the different vertical-barpjlambda>, the constituent p 2 >0, spin-j UIR's of the Poincare group. For the massless case, normalized basis vectors vertical-barp 2 =0, lambda 0 ; plambda> are similarly constructed, where lambda 0 is the ''superhelicity.'' Matrix elements of the supersymmetry generators, in these bases, are explicitly given. The ''sigma basis'' is used to define weight diagrams for the massive UIR's of supersymmetry, and their properties are briefly described. Eigenfunctions ω/sub sigma/(theta) are also defined, and their connection with the reduction of higher spin massive superfields PHI/subJ/(x,theta) is discussed. Finally, it is shown how gauge dependence necessarily arises with certain massless superfields. The massless scalar superfield, both gauge-dependent and gauge-independent, is discussed as an example

  20. Massive rectal bleeding from colonic diverticulosis

    African Journals Online (AJOL)

    ABEOLUGBENGAS

    Rapport De Cas: Nous mettons un cas d'un homme de 79 ans quiàprésente une hémorragie rectal massive ... cause of overt lower gastrointestinal (GI) ... vessels into the intestinal lumen results in ... placed on a high fibre diet, and intravenous.